1-methylnicotinamide and its structural analog 1,4-dimethylpyridine for the prevention of cancer metastasis
© The Author(s). 2016
Received: 26 April 2016
Accepted: 28 June 2016
Published: 13 July 2016
1-methylnicotinamide (1-MNA), an endogenous metabolite of nicotinamide, has recently gained interest due to its anti-inflammatory and anti-thrombotic activities linked to the COX-2/PGI2 pathway. Given the previously reported anti-metastatic activity of prostacyclin (PGI2), we aimed to assess the effects of 1-MNA and its structurally related analog, 1,4-dimethylpyridine (1,4-DMP), in the prevention of cancer metastasis.
All the studies on the anti-tumor and anti-metastatic activity of 1-MNA and 1,4-DMP were conducted using the model of murine mammary gland cancer (4T1) transplanted either orthotopically or intravenously into female BALB/c mouse. Additionally, the effect of the investigated molecules on cancer cell-induced angiogenesis was estimated using the matrigel plug assay utilizing 4T1 cells as a source of pro-angiogenic factors.
Neither 1-MNA nor 1,4-DMP, when given in a monotherapy of metastatic cancer, influenced the growth of 4T1 primary tumors transplanted orthotopically; however, both compounds tended to inhibit 4T1 metastases formation in lungs of mice that were orthotopically or intravenously inoculated with 4T1 or 4T1-luc2-tdTomato cells, respectively. Additionally, while 1-MNA enhanced tumor vasculature formation and markedly increased PGI2 generation, 1,4-DMP did not have such an effect. The anti-metastatic activity of 1-MNA and 1,4-DMP was further confirmed when both agents were applied with a cytostatic drug in a combined treatment of 4T1 murine mammary gland cancer what resulted in up to 80 % diminution of lung metastases formation.
The results of the studies presented below indicate that 1-MNA and its structural analog 1,4-DMP prevent metastasis and might be beneficially implemented into the treatment of metastatic breast cancer to ensure a comprehensive strategy of metastasis control.
Keywords1-methylnicotinaimide chloride 1,4-dimethylpyridinium chloride Metastasis Angiogenesis Combined therapy Breast cancer
1-methylnicotinamide (1-MNA), an endogenous metabolite of nicotinamide (NA), is synthetized in the reaction of nicotinamide N-methyltransferase (NNMT), an enzyme expressed predominantly in the liver, where it plays a pivotal role in the N-methylation of NA and possibly other pyridine compounds . However, NNMT expression has also been reported in a number of other types of cells and organs, including rapidly proliferating cancer cells [2–4] or the brains of the patients suffering from Parkinson’s disease . For decades it has been nicotinamide, a substrate for the NNMT reaction that has attracted attention as a possible therapeutic agent endowed with pharmacological activities [6–9]. Meanwhile, 1-MNA has been considered an inactive metabolite . Only recently has some evidence for the possible therapeutic application of 1-MNA emerged. The first signals for its pharmacological potential date back to 2003, when Gebicki et al. described its anti-inflammatory activity in skin disorders such as acne or contact dermatitis , which was further confirmed in an additional study involving patients with rosacea . In turn, studies by Chlopicki et al. demonstrated that the mechanisms of action of 1-MNA involve the activation of PGI2 release driven by cyclooxygenase 2 (COX-2) . PGI2 releasing capacity of 1-MNA was later shown to afford not only anti-thrombotic  but also fibrinolytic , anti-inflammatory [11, 15] and gastroprotective  effects. Interestingly, 1-MNA did not directly either affect the activity of leucocytes [15, 17] or release PGI2 in the perfused rat hindquarters model . Still, 1-MNA, due to its PGI2 releasing capacity, might serve as a hepatoprotective agent that protects against concanavalin A induced liver injury  through the downregulation of interleukin-4 (IL-4) and tumor necrosis factor-α signalization (TNF-α) . In addition to its anti-platelet, anti-thrombotic and anti-inflammatory activities, 1-MNA has also been shown to restore endothelial function in diabetic hypertriglycemic rats , as well as to improve endothelial function in humans .
Given the reports demonstrating that PGI2 displays anti-metastatic activity [23, 24], and the PGI2 releasing activity of 1-MNA , the potential application of exogenous 1-MNA to prevent metastatic cancer seems to be justified. However, currently only limited reports on the in vivo anti-cancer activity of 1-MNA are available, including the daily use of 1-MNA in mice bearing murine leukemia L1210 that resulted in about a 50 % lifespan increase  or the disclosure of the use of 1-MNA in the prevention of experimental metastases formation .
In his patent application Gebicki et al.  discloses also the use of the 1-MNA’s analog, 1,4-dimethylpyridine (1,4-DMP), another pyridine compound naturally occurring in roasted coffee seeds. 1,4-DMP is believed to be at least partially responsible for health-beneficial effects of coffee and as such has been shown to inhibit thrombus formation in vivo. As it has been observed for 1-MNA, the antihrombotic activity of 1,4-DMP depends on the prostacyclin-related mechanisms . What is more, results of our preliminary studies have shown that 1,4-DMP inhibits metastases formation in the model of spontaneously metastasizing murine mammary gland cancer (4T1) . Nevertheless, none of the mentioned reports provide any detailed evidence of the impact revealed by 1-MNA or 1,4-DMP on the growth and metastasis of solid tumors.
Metastasis is a complex process comprising several discrete steps that result in the formation of secondary lesions localized at a distance from the primary tumor. Due to their characteristics, metastases often fail to respond to standard chemotherapy and appear to be inaccessible for irradiation or surgical treatment. Therefore, their development usually leads to a dramatic deterioration in survival prognosis, which, in turn, justifies the common urge for modern therapeutic regimes enabling the control of metastatic dissemination. Since it is undeniable that successful metastasis relies on the complex interactions between cancer cells and host body tissues, one can expect that selective interference with such an interaction would reduce metastatic potential. The phenomena occurring in a host body tissues that have been suggested to beneficially influence cancer progression comprise, for example, tumor vessel formation, tumor immune editing and also tumor cell induced platelet aggregation (TCIPA). The latter seems to be of particular interest, as it not only promotes cancer metastasis but also increases patients mortality due to cardiovascular incidents . Nevertheless, platelets undoubtedly contribute to metastasis efficiency as they physically shield migrating cancer cells in the bloodstream, facilitate immune evasion [30, 31], and promote cancer cell adhesion to the endothelium of the microvasculature in a target tissue [32, 33]. Thus, platelets appear to be a promising alternative target for metastasis prevention. Inhibition of metastases development by anti-platelet pharmacotherapy has been previously studied, and to date multiple data on the anti-metastatic potential of anti-platelet agents have been reported [34–37]. PGI2is the most potent endogenous anti-platelet agent that, together with its analogs, has been shown to prevent cancer metastasis [23, 38–42]; however, the unfavorable short lifetime of the parent molecule and the hypotensive action of its potent analogs limit their application.
Given the PGI2-related mechanism of action of 1-MNA and 1,4-DMP, we decided to investigate whether these compounds may possess any significant anti-cancer activity in the model of highly metastatic murine mammary gland cancer (4T1). The secondary aim of the presented study was to determine the possibility to utilize both of the compounds in a therapeutic regimen additionally comprising cyclophosphamide.
Drugs, doses and therapeutic regimens applied in the presented studies
Route of administration
Experimental metastasis (Fig. 1)
Per os in drinking water
Treatment initiated 7 days prior cancer transplantation and continued to the end of the experiment
Spontaneous metastasis (single drug treatment) (Fig. 2)
Per os in drinking water
Continuously from the 7th day of the experiment to the end of the experiment
Matrigel plugs (Fig. 3)
Per os in drinking water
Continuously starting from the day of matrigel plugs transplantation
On days 0, 3, 5
Per os in drinking water
Continuously from the 1st day of the experiment to the end of the experiment
From the 7th day of the experiment, 3 times each week
Strains and number of mice used in the experiments
Cell culture and transplantation
The mouse mammary adenocarcinoma 4T1 cells were obtained from the American Type Culture Collection (ATCC, USA). Cells were cultured in RPMI 1640 (IIET, Poland) with Opti-MEM® (Life Technologies, USA) (1:1 v/v) medium with 5 % fetal bovine serum (HyClone, Thermo Fisher Scientific Inc. UK), supplemented with 4.5 g/L glucose, 2 mM glutamine, 1.0 mM sodium pyruvate (all from Sigma-Aldrich, Germany) and antibiotics (penicillin and streptomycin – Polfa Tarchomin, Poland). The mouse mammary adenocarcinoma 4T1-luc2-tdTomato cell line stably expressing the firefly luciferase gene and tdTomato fluorescent protein was obtained from Caliper Life Sciences Inc. (USA). Cells were cultured in RPMI 1640 + Gluta-MAX™ medium (Life Technologies, USA) supplemented with 10 % fetal bovine serum (Sigma-Aldrich, Germany) and antibiotics (penicillin and streptomycin – Polfa Tarchomin, Poland). Both cell line cultures were maintained at 37 °C in a humidified atmosphere with 5 % CO2.
Irrespective of the tumor model applied prior to the transplantations, all cells were trypsinized (IIET, Poland), centrifuged (200 g, 4 °C, 5 min) and counted. For the model of spontaneous metastasis, 4T1 cells were resuspended in Hank’s Balanced Salt Solution (HBSS; IIET, Poland) such that a suspension of 3 × 105 4T1 cells in 0.05 ml of HBSS was inoculated into the mammary gland of female BALB/c mice. For the model of experimental metastasis, 4T1-luc2-tdTomato cells were resuspended in HBSS such that a suspension of 3 × 105 4T1-luc2-tdTomato cells in 0.1 ml HBSS was injected into the tail vein of each female BALB/c Nude mice. For the model of matrigel plugs, 4T1 cells were resuspended in the mixture of matrigel (BD Matrigel Basement Matrix High Concentration, Becton, Dickinson and Company, USA) and HBSS (5:1) such that 1 × 104 cells suspended in 0.3 ml mixture was injected subcutaneously on the right flank of each female BALB/c mice.
Estimation of the anti-tumor activity
Where TGI is the tumor growth inhibition value, TVN is the mean tumor volume calculated for the studied experimental group and TVC is the mean tumor volume calculated for the control group of animals.
Evaluation of the anti-metastatic effect
To determine the anti-metastatic activity of the compounds, the lungs of tumor bearing mice were excised, weighed and transferred into 5 % solution of buffered formalin. After tissue fixation, metastatic foci were counted visually. In the model of experimental metastasis, in vivo visualizations of the metastatic foci localized in lungs were performed every third day, starting from the tenth day of the experiment using an In vivo MS FX PRO system (Carestream Health INC., USA). In brief, about ten minutes before imaging, D-luciferine potassium salt (Synchem INC., Germany) was administered to each mouse intraperitoneally at the dose of 150 mg/kg. Then, animals were anesthetized with a 3–5 % (v/v) mixture of isoflurane (Forane, Abbott Laboratories, USA) in synthetic air (200 ml/min). Anesthesia was maintained by means of individual masks providing a 1.5–2 % (v/v) mixture of isoflurane and synthetic air. Visualization was carried out using the following settings: for X-Ray t = 2 min, f-stop = 5.57, FOV = 198.6; for luminescence capture t = 3 min, binning 2 × 2, f-stop = 5.57, FOV = 198.6. Images were analyzed with Carestream MI SE software (Carestream Health INC., USA). The intensity of the luminescent signal is presented as the sum intensity of the region of interest and expressed in arbitrary units [a.u.].
Evaluation of tumor angiogenesis
The influence of 1-MNA and 1,4-DMP on tumor angiogenesis was evaluated in the model of spontaneously metastasizing 4T1 tumors and confirmed in the model of matrigel plugs. Analyzes were performed by means of ultrasound imaging of tumor perfusion or immunohistochemistry staining of platelet endothelial cell adhesion molecules (PECAM-1; CD31) in the matrigel matrix, respectively. For the ultrasound imaging, the MicroMarker™ Contrast Agent (VisualSonics, Canada) was prepared according to the manufacturer’s instructions. Animals were anesthetized with the 3–5 % (v/v) mixture of isoflurane (Forane, Abbott Laboratories, USA) in synthetic air (200 ml/min) and placed on an animal handling station equipped with an individual mask providing a 1.5–2 % (v/v) mixture of isoflurane and synthetic air. The position of the handling station was adjusted so that the central section of the tumor was being visualized and the contrast agent was injected into the tail vein of the animal. The signal of the contrast marker accumulating in the tumor mass was recorded using a probe of 13–24 Mhz frequency (MS250, VisualSonics, Canada). Next, the wash-in rate was calculated using Vevo LAB 1.7.1. Software (VisualSonics, Ontario, Canada).
Immunohistochemistry was performed in matrigel plugs (isolated from mice on the 7th day after the transplantation) which were fixed in buffered formalin and then cut into 4-μm-thick sections that were subsequently dewaxed with xylene and rehydrated in a gradient of ethanol. For antigen retrieval, sections were heated in a water bath at 96 °C for 20 min with EnVision™ FLEX Target Retrieval Solution, High pH (Dako®, Carpinteria, USA). Endogenous peroxidase activity was quenched in EnVision™ FLEX Peroxidase-Blocking Reagent for 5 min. Thereafter, sections were incubated with primary antibody against PECAM-1 (diluted in 1:50 ratio). Subsequently, sections were washed in EnVision™ FLEX Wash Buffer and detection system EnVision™ FLEX/HR SM802 was added for 30 min at room temperature. The reaction was developed using 3,3-diaminebezidine tetrahydrochloride solution (DAB, EnVision™ FLEX DAB+ Chromogen (DAKO®, Carpinteria, USA). Finally, sections were washed in distilled water and nuclei were counterstained in hematoxylin, preparations were dehydrated in an alcohol gradient and coverslip mounted. Mean vessel density was evaluated by counting PECAM-1-positive vessels in 5 different fields of view at 200× magnitude.
Platelet activation status
Blood samples from the experimental animals were collected on the last day of the experiments. Samples were collected into tubes containing 0.05 ml of 5 % ethylenediaminetetraacetic acid (EDTA) solution (Sigma-Aldrich, Germany). Then, blood plasma was obtained by centrifugation (2000 g, 15 min, 4 °C) and stored at −80 °C until further analyzed. Prostacyclin generation in the treated mice was determined by the quantification of plasma 6-keto-prostaglandin F1α (6-keto-PGF1α) levels. Platelet activation status was estimated on the basis of thromboxane B2 (TXB2), von Willebrand factor (vWF) and soluble P-selectin plasma concentrations. All analyzes were conducted using commercial ELISA kits available from Cusabio Biotech CO., Ltd (Wuhan, China), according to the manufacturer’s instructions.
E-cadherin/N-cadherin expression in tumor tissue
Protein expression in 4T1 tumor tissue was analyzed according to the standard Western blot procedure . In brief, samples of tumor tissue collected and immediately frozen on the last day of the experiments were homogenized in RIPA Buffer (Sigma-Aldrich, Germany) using a FastPrep®-24 MP Bio device (Mp Biomedicals LLC., USA) with the following settings: CP 24x2, 6 m/s, 40 s. Protein content in all samples was analyzed using a Bio-Rad Protein Assay (Bio-Rad Laboratories Inc., USA) according to the manufacturer’s protocol. Samples containing 100 μg of protein were separated on the pre-cast 4–20 % gradient gels (Bio-Rad Laboratories, Inc., USA) and transferred onto 0.45 μm polyvinylidene fluoride (PVDF) membranes (Merck Millipore, USA). Next the membranes were probed with primary rabbit polyclonal anti-E-cadherin, anti-N-cadherin antibodies (1:1000, both from Proteintech Group, USA) or rabbit anti-β-actin (1:1000, Sigma-Aldrich, Germany) antibody. Finally, analyzed proteins were detected with secondary anti-rabbit antibody conjugated with alkaline phosphatase (ECF Western Blotting Reagent Pack, GE Healthcare, Great Britain) and the signal was developed according to manufacturer’s instruction. Blots were visualized in Image Station 4000MM (Carestream Healthcare Inc., USA) and analyzed with ImageJ Software, as follows. The total E-cadherin cellular content comprising mature and unprocessed E-cadherin (with a molecular weight of approximately 100 and 130 kDa, respectively) was calculated. Then, E-cadherin and N-cadherin contents were normalized to β-actin. Finally, E-cadherin to N-cadherin ratios in individual samples were calculated and presented as median values.
Systemic toxicity of the anti-cancer treatment
where: WN is the mean body weight of the animals on each successive day of the experiment; W0 is the mean body weight of the animals calculated for day 0 of the experiment.
Data normality was estimated using the Shapiro-Wilk test with a predetermined p < 0.05 value. The Tukey-Kramer multiple comparisons test for parametric data or the Kruskal Walis Test for non-parametric data were applied; p values lower than 0.05 were considered significant. All calculations were performed using STATISTICA 10 (StatSoft Inc., USA) or GraphPad Prism 6 (GraphPad Software, Inc., USA) software.
Unless stated otherwise all data presented on graphs correspond to median values ± min/max.
Anti-cancer activity of 1-MNA and 1,4-DMP in a single drug therapy
Anti-cancer activity of 1-MNA and 1,4-DMP in a combined treatment with cyclophosphamide
Interestingly, in tumor tissue isolated from mice treated with 1-MNA alone or in combination with cyclophosphamide, a higher E-cadherin expression that was accompanied with the lower N-cadherin levels was observed. The estimated E-cadherin to N-cadherin ratio in the tissue was more than twice as high as in the control untreated animals. On the other hand, such phenomena did not occur in mice receiving 1,4-DMP either in a single or combined treatment regime (Fig. 4j–k).
Toxicity of the anti-cancer treatment
Anti-thrombotic, anti-inflammatory, and vasoprotective properties of 1-MNA ascribed to its contribution to PGI2 release have been proposed to have therapeutic significance, for example, in atherosclerosis . On the other hand, when studied for its anti-metastatic properties, PGI2, which is the most potent endogenous inhibitor of platelet aggregation, has proven to be an efficient metastasis inhibitor [23, 45]. Stable analogs of PGI2 also displayed anti-cancer activity [38, 40–42]. However, the short lifetime of PGI2 and the side effects of its analogs when given systemically may limit their therapeutic application in oncology. Therefore, a PGI2-releasing agent, such as 1-MNA or its structural analog 1,4-DMP, might become an interesting alternative to the use of PGI2 in the treatment of metastatic cancer. Here, we have demonstrated that in the murine model of metastatic breast cancer 1-MNA and 1,4-DMP both display anti-metastatic activity, particularly during the vascular phase of metastasis and if combined with cyclophosphamide may ensure an efficient strategy for the prevention of mammary gland tumor’s metastases formation.
In two separate in vivo studies, both 1-MNA and 1,4-DMP inhibited to some degree the spontaneous formation of 4T1 tumor lung metastases while neither of them influenced the growth of 4T1 primary tumors. Moreover, the observed anti-metastatic effect was strongly related to the time of therapy initiation, being more pronounced while 1-MNA and 1,4-DMP were administrated from the time of 4T1 cells orthotopic transplantation. This, in turn, suggests that the activity of both compounds results in the prevention of early 4T1 tumor’s metastases formation rather than in any direct influence on established lesions. Such anti-metastatic activity of 1-MNA and 1,4-DMP was further confirmed in the model of experimental metastasis of 4T1-luc2-tdTomato cells that stably express red fluorescent protein and the gene for firefly luciferase. In the study, mice pretreated with either 1-MNA or 1,4-DMP revealed less pronounced metastatic disease characterized by a delayed onset indicating impaired 4T1 cells homing in the lungs. Such results remain in agreement with the previously disclosed anti-metastatic activity of 1-MNA and 1,4-DMP  and other published studies suggesting that drugs affecting platelet aggregation or endothelial inflammation might beneficially influence the vascular stage of metastatic dissemination, including adhesion of migrating cancer cells to the vessel wall and subsequent extravasation to the lungs [46, 47].
Possible implementation of 1-MNA and 1,4-DMP in the therapy of metastatic breast cancer was further confirmed when both compounds were administrated with cyclophosphamide to 4T1 tumor-bearing mice. Interestingly, in the applied tumor model not only did 1-MNA and 1,4-DMP inhibit lung metastases formation but also they beneficially influenced the anti-tumor activity of the cytostatic drug. Pronounced tumor growth inhibition in mice receiving the combined treatments was associated with diminished TXB2 plasma levels suggesting potential involvement of platelet-related mechanisms in the anti-cancer activity of both investigated molecules. Moreover, when given with cyclophosphamide, 1,4-DMP further improved the anti-metastatic efficacy of the chemotherapeutic.
Since metastases formation strongly depends on angiogenesis yield , we additionally decided to estimate the influence of 1-MNA and 1,4-DMP on vessel formation in either mammary gland tumor mass or matrigel plugs. The results of the studies revealed surprisingly distinct effects of 1-MNA and 1,4-DMP on vasculature development. While 1-MNA stimulated the formation of blood vessels in both angiogenesis models employed, 1,4-DMP did not affect vasculature formation when compared to the control group of animals. Such an observation is not surprising in terms of the proven PGI2-dependent activity of 1-MNA; however, it might indicate that either the PGI2 releasing capacity of 1,4-DMP is lower as compared with 1-MNA, or there is another anti-metastatic mechanism of action that could be featured by this compound. Such an assumption is further supported by the observation that, while both agents seemed to inhibit platelet activity as manifested by the reduced plasma level of TXB2, only 1-MNA induced a profound increase in PGI2 concentration, as reflected in elevated 6-keto-PGF1α levels. It is known that PGI2 displays pro-angiogenic activity that has been previously shown both in vitro and in vivo, in tumor as well as in ischemia models [49, 50–52]. In fact, Osawa et al. has shown that in tumor endothelial cells (TECs) the expression of the receptor for PGI2 is upregulated, but also that TECs secrete higher levels of PGI2, which in turn stimulates angiogenesis in an autocrine manner . Accordingly, we suspect that observed in our study increased capillary formation, induced in response to the treatment with 1-MNA, resulted from PGI2-releasing activity of the compound. In case of our studies, however, such enhanced tumor angiogenesis did not lead to enhanced tumor growth or metastatic dissemination, but contrarily to lesser number of diagnosed metastases and increased efficacy of the applied chemotherapeutic. Possibly, such effect emerged from the phenomena of tumor vessels normalization that could occur in response to 1-MNA. Such effect is not unparalleled as the relation between vascular permeability and the drug transport efficiency into tumors has been previously described . Also, Li et al. shows that the prevention of VEGF-A induced tumor vasculature leakage increase chemotherapy efficacy and what is even more important the number of distant metastases .
It has been previously described that in order to form distant metastasis immobile tumor cells undergo epithelial to mesenchymal transition (EMT), a process in which non-invasive cells loose their epithelial character and develop mesenchymal features to eventually acquire more invasive potential. It has been shown that on the molecular level, EMT is driven by phosphatidylinositol-3-kinase/Akt (PI3K/Akt)  and extracellular signal regulated kinase 1/2 (ERK1/2)  signaling pathways that when activated contributed to an enhanced metastasis . Activation of PI3K/Akt and ERK1/2 in cancer cells eventually leads to the down-regulated E-cadherin and up-regulated N-cadherin expression, among others. Accordingly, decreased E-cadherin cellular content was shown to promote cancer cells motility and invasiveness in vitro and consequently to correlate with worsened survival prognosis in patients [58, 59]. In our study, however, enhanced E-cadherin to N-cadherin expression ratio was observed in mammary gland tumor tissue isolated only from mice treated with 1-MNA or 1-MNA given with cyclophosphamide. It seems probable that 1-MNA exerted its anti-metastatic activity on the primary mammary gland tumor level leading to diminished metastatic potential of 4T1 cells, while the activity of 1,4-DMP is not directly related to the tumor tissue. Such observation further supports the idea that 1-MNA and 1,4-DMP affect malignant breast cancer progression in different manners.
Besides the undeniable beneficial anti-metastatic activity of the combined treatment comprising either 1-MNA or 1,4-DMP and cyclophosphamide, its sustained low toxicity comparable to that revealed by the cytostatic drug given alone is probably the most crucial factor from the clinical point of view. The most undesirable side effect of a treatment implementing anti-platelet drugs is bleeding [60–62]. However, in our study we have not observed any incidence of treatment-related deaths. Moreover, the body weight of the treated animals was constantly increasing throughout the study. This might be a consequence of the PGI2 releasing activity of the employed agents. PGI2 has been shown to be a more potent inhibitor of platelet-platelet interactions than an inhibitor of platelet adhesion to damaged endothelium ; therefore, it seems to constitute a safe alternative for other non-selective platelet inhibitors. Moreover, the recently described beneficial hepatoprotective activity of 1-MNA and NMMT  might suggest its potential preventive activity also against liver damages induced by chemotherapy.
On the other hand, recently published data showing an elevated expression of NMMT in a number of human tumor types and its possible involvement in proliferation, tumorogenic capacity and invasiveness of cancer cells [2, 3, 52, 65] may cause major concerns when considering implementation of 1-MNA and its analogs into the anti-cancer therapeutic regimes. Not only NMMT but also 1-MNA itself was shown to promote cellular growth what in a study of Parsons et al. resulted in the prolonged survival and enhanced proliferation of neurobastoma cells in vitro . However, in our preliminary studies we have established that neither 1-MNA nor 1,4-DMP promote the proliferation of breast, prostate or colon cancer cells in vitro, even at the concentrations up to 1000 μg/ml. On the contrary, we have observed that while 1-MNA at such concentration did not reveal any influence on the growth of tested cells, 1,4-DMP actually inhibited it in 20 % to almost 50 %, depending on the cell line tested (Additional file 1: Table S1). Additionally, as evidenced by the results presented above neither of studied pyridine compounds enhanced the growth of 4T1 primary tumors in vivo. Such discrepancy observed between the experimental results regarding the activity of NMMT in tumor cells is not uncommon. For example, while a number of reports indicate the correlation between the NMMT expression and the degree of malignancy  other suggest that tumors express high levels of NMMT that promotes early phase of tumorogenicity, but has to be down-regulated to enable metastasis. In fact, these reports attribute NNMT’s high expression to the prolonged patients’ survival [67–69]. The exact mechanisms involved in the effects of NNMT in cancer cells are not entirely clear, however, it is suspected that they depend on the regulation of the processes based on the availability of NA and methyl groups . Accordingly, down-regulation of NMMT was shown to induce apoptosis in human breast cancer cells . It was reported that 1-MNA might act as NMMT inhibitor  what at least in theory could increase the bioavailability of intracellular NA and thus endure the NMMT effect leading to the induced apoptosis and chemosensitization of cancer cells [72, 73]. However, in the light of the results presented here, it seems that a possible direct effect of 1-MNA on 4T1 murine mammary gland cells, if any, is neglectable as it did not result in an enhanced tumorogenesis or chemoresistance development. On the contrary, implementation of 1-MNA and its analogue 1,4-DMP to the treatment of metastatic mammary gland cancer has proven beneficial. Therefore, concerns regarding the use of 1-MNA in the anticancer therapies that may arise on the basis of recently published NMMT activity in cancer cells seem to be unjustified as pro-metastatic activity of NNMT seems to be related to the intracellular methylation status in cancer cells, while exogenous 1-MNA exerts its anti-inflammatory and anti-thrombotic properties in circulation and thus indirectly affect cancer cells metastasis.
The results of the studies presented above indicate that 1-MNA and its analog, 1,4-DMP, might be beneficially implemented into the treatment of metastatic breast cancer to ensure a more comprehensive strategy of metastasis control than that based on chemotherapy alone. However, additional studies should be performed to explain their mechanism of action in more detail and to establish whether the observed anti-metastatic activity of both compounds is restricted only to breast cancer or whether it is applicable to a broader range of malignant tumors.
%BW, % of body weight; 1,4-DMP, dimethylpyridinium chloride; 1-MNA, 1-methylnicotinamide chloride; 6-keto-PGF1α, 6-keto-prostaglandin F1α; AU, arbitrary units; CLO, clopidogrel; COX-2, cyclooxygenase 2; CP, cyclophosphamide; EDTA, ethylenediaminetetraacetic acid; EMT, epithelial to mesenchymal transition; ERK1/2, extracellular signal regulated kinase 1/2; HBSS, Hanks Balanced Salt Solution; IL-4, interleukin 4; NA, nicotinamide; NADH, nicotinamide adenine dinucleotide; NADPH, nicotinamide adenine dinucleotide phosphate; NNMT, nicotinamide N-methyltransferase; PI3K/Akt, phosphatidylinositol-3-kinase/Akt; PS, pyridinium salts; PVDF, polyvinylidene fluoride; ROS, reactive oxygen species; rpm, round per minute; SDS, sodium dodecylosulphate; TCIPA, tumor cell induced platelet; TECs, tumor endothelial cells; TGI, tumor growth inhibition; TNF-α, tumor necrosis factor α; TV, tumor volume; TXB2, thromboxane B2; VCAM-1, vascular cell adhesion molecule 1; vWF, von Willebrand Factor
Availability of data and material
All data are presented as calculated mean with SD or median with min- max values, moreover, the data concerning lung metastases count are presented as values (dots) for individual mice.
The data which are not shown in the main body of manuscript are presented in supplementary file.
AB, JW and SC conceived and designed the experiments; AM and JG synthetized and provided pyridinium salts; AB, MS, ANG and MN performed the experiments; AB analyzed the data and wrote the paper. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Consent for publication
Ethics approval and consent to participate
All animal experiments were performed according to the Interdisciplinary Principles and Guidelines for the Use of Animals in Research, Marketing and Education issued by the New York Academy of Sciences’ Ad Hoc Committee on Animal Research and were approved by the 1st Local Committee for Experiments with the Use of Laboratory Animals, Wroclaw, Poland.
This study was supported by the European Union from the resources of the European Regional Development Fund within the Innovative Economy Program (grant coordinated by the JCET-UJ, No POIG.01.01.02–00–069/09) and The National Center for Research and Development under the Polish Strategic Framework Program STRATEGMED (grant coordinated by JCET-UJ No STRATEGMED1/233226/11/NCBR/2015). Publication was supported by Wroclaw Centre of Biotechnology within a Program The Leading National Research Centre (KNOW) for years 2014–2018.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- Alston TA, Abeles RH. Substrate specificity of nicotinamide methyltransferase isolated from porcine liver. Arch Biochem Biophys. 1988;260:601–8.View ArticlePubMedGoogle Scholar
- Yu T, Wang YT, Chen P, Li YH, Chen YX, Zeng H, Yu AM, Huang M, Bi HC. Effects of nicotinamide N-methyltransferase on PANC-1 cells proliferation, metastatic potential and survival under metabolic stress. Cell Physiol Biochem. 2015;35:710–21.View ArticlePubMedGoogle Scholar
- Zhang J, Wang Y, Li G, Yu H, Xie X. Down-regulation of nicotinamide N-methyltransferase induces apoptosis in human breast cancer cells via the mitochondria-mediated pathway. PLoS One. 2014;9:e89202.View ArticlePubMedPubMed CentralGoogle Scholar
- Pozzi V, Sartini D, Morganti S, Giuliante R, Di Ruscio G, Santarelli A, Rocchetti R, Rubini C, Tomasetti M, Giannatempo G, et al. RNA-mediated gene silencing of nicotinamide N-methyltransferase is associated with decreased tumorigenicity in human oral carcinoma cells. PLoS One. 2013;8:e71272.View ArticlePubMedPubMed CentralGoogle Scholar
- Parsons RB, Smith ML, Williams AC, Waring RH, Ramsden DB. Expression of nicotinamide N-methyltransferase (E.C. 22.214.171.124) in the Parkinsonian brain. J Neuropathol Exp Neurol. 2002;61:111–24.View ArticlePubMedGoogle Scholar
- Crino A, Schiaffini R, Manfrini S, Mesturino C, Visalli N, Beretta Anguissola G, Suraci C, Pitocco D, Spera S, Corbi S, et al. A randomized trial of nicotinamide and vitamin E in children with recent onset type 1 diabetes (IMDIAB IX). Eur J Endocrinol. 2004;150:719–24.View ArticlePubMedGoogle Scholar
- Chen AC, Martin AJ, Choy B, Fernandez-Penas P, Dalziell RA, McKenzie CA, Scolyer RA, Dhillon HM, Vardy JL, Kricker A, et al. A Phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention. N Engl J Med. 2015;373:1618–26.View ArticlePubMedGoogle Scholar
- Maiese K, Chong ZZ. Nicotinamide: necessary nutrient emerges as a novel cytoprotectant for the brain. Trends Pharmacol Sci. 2003;24:228–32.View ArticlePubMedGoogle Scholar
- Hiromatsu Y, Sato M, Yamada K, Nonaka K. Inhibitory effects of nicotinamide on recombinant human interferon-gamma-induced intercellular adhesion molecule-1 (ICAM-1) and HLA-DR antigen expression on cultured human endothelial cells. Immunol Lett. 1992;31:35–9.View ArticlePubMedGoogle Scholar
- Surjana D, Halliday GM, Damian DL. Role of nicotinamide in DNA damage, mutagenesis, and DNA repair. J Nucleic Acids. 2010; 2010:Article ID 157591.Google Scholar
- Gebicki J, Sysa-Jedrzejowska A, Adamus J, Wozniacka A, Rybak M, Zielonka J. 1-Methylnicotinamide: a potent anti-inflammatory agent of vitamin origin. Pol J Pharmacol. 2003;55:109–12.View ArticlePubMedGoogle Scholar
- Wozniacka A, Wieczorkowska M, Gebicki J, Sysa-Jedrzejowska A. Topical application of 1-methylnicotinamide in the treatment of rosacea: a pilot study. Clin Exp Dermatol. 2005;30:632–5.View ArticlePubMedGoogle Scholar
- Chlopicki S, Swies J, Mogielnicki A, Buczko W, Bartus M, Lomnicka M, Adamus J, Gebicki J. 1-Methylnicotinamide (MNA), a primary metabolite of nicotinamide, exerts anti-thrombotic activity mediated by a cyclooxygenase-2/prostacyclin pathway. Br J Pharmacol. 2007;152:230–9.View ArticlePubMedPubMed CentralGoogle Scholar
- Mogielnicki A, Kramkowski K, Pietrzak L, Buczko W. N-methylnicotinamide inhibits arterial thrombosis in hypertensive rats. J Physiol Pharmacol. 2007;58:515–27.PubMedGoogle Scholar
- Bryniarski K, Biedron R, Jakubowski A, Chlopicki S, Marcinkiewicz J. Anti-inflammatory effect of 1-methylnicotinamide in contact hypersensitivity to oxazolone in mice; involvement of prostacyclin. Eur J Pharmacol. 2008;578:332–8.View ArticlePubMedGoogle Scholar
- Brzozowski T, Konturek PC, Chlopicki S, Sliwowski Z, Pawlik M, Ptak-Belowska A, Kwiecien S, Drozdowicz D, Pajdo R, Slonimska E, et al. Therapeutic potential of 1-methylnicotinamide against acute gastric lesions induced by stress: role of endogenous prostacyclin and sensory nerves. J Pharmacol Exp Ther. 2008;326:105–16.View ArticlePubMedGoogle Scholar
- Biedron R, Ciszek M, Tokarczyk M, Bobek M, Kurnyta M, Slominska EM, Smolenski RT, Marcinkiewicz J. 1-Methylnicotinamide and nicotinamide: two related anti-inflammatory agents that differentially affect the functions of activated macrophages. Arch Immunol Ther Exp (Warsz). 2008;56:127–34.View ArticleGoogle Scholar
- Mogielnicki A, Kramkowski K, Hermanowicz JM, Buczko W. N-methylnicotinamide failed to induce endothelial prostacyclin release in perfused rat hindquarters. Pharmacol Rep. 2008;60:1025–9.PubMedGoogle Scholar
- Sternak M, Khomich TI, Jakubowski A, Szafarz M, Szczepanski W, Bialas M, Stojak M, Szymura-Oleksiak J, Chlopicki S. Nicotinamide N-methyltransferase (NNMT) and 1-methylnicotinamide (MNA) in experimental hepatitis induced by concanavalin A in the mouse. Pharmacol Rep. 2010;62:483–93.View ArticlePubMedGoogle Scholar
- Jakubowski A, Sternak M, Jablonski K, Ciszek-Lenda M, Marcinkiewicz J, Chlopicki S. 1-Methylnicotinamide protects against liver injury induced by concanavalin A via a prostacyclin-dependent mechanism: A possible involvement of IL-4 and TNF-alpha. Int Immunopharmacol. 2016;31:98–104.View ArticlePubMedGoogle Scholar
- Bartus M, Lomnicka M, Kostogrys RB, Kazmierczak P, Watala C, Slominska EM, Smolenski RT, Pisulewski PM, Adamus J, Gebicki J, Chlopicki S. 1-Methylnicotinamide (MNA) prevents endothelial dysfunction in hypertriglyceridemic and diabetic rats. Pharmacol Rep. 2008;60:127–38.PubMedGoogle Scholar
- Domagala TB, Szeffler A, Dobrucki LW, Dropinski J, Polanski S, Leszczynska-Wiloch M, Kotula-Horowitz K, Wojciechowski J, Wojnowski L, Szczeklik A, Kalinowski L. Nitric oxide production and endothelium-dependent vasorelaxation ameliorated by N1-methylnicotinamide in human blood vessels. Hypertension. 2012;59:825–32.View ArticlePubMedGoogle Scholar
- Honn KV. Inhibition of tumor cell metastasis by modulation of the vascular prostacyclin/thromboxane A2 system. Clin Exp Metastasis. 1983;1:103–14.View ArticlePubMedGoogle Scholar
- Honn KV, Cicone B, Skoff A. Prostacyclin: a potent antimetastatic agent. Science. 1981;212(4500):1270–2.Google Scholar
- Wieczorkowska M, Szajerski P, Michalski R, Adamus J, Marciniak A, Gebicki J, Ciesielska E, Szmigiero L, Lech-Maranda E, Szmigielska-Kaplon A, Robak T. Cytotoxic activity of the selected pyridinium salts against murine leukemia L1210. Pharmacol Rep. 2007;59:216–23.PubMedGoogle Scholar
- Gebicki J, Marcinek A, Chlopicki S. Use of quaternary pyridinium salts for inhibiting cancer metastases. European patent EP 2 211 858, 2015.23.Google Scholar
- Kalaska B, Piotrowski L, Leszczynska A, Michalowski B, Kramkowski K, Kaminski T, Adamus J, Marcinek A, Gebicki J, Mogielnicki A, Buczko W. Antithrombotic effects of pyridinium compounds formed from trigonelline upon coffee roasting. J Agric Food Chem. 2014;62:2853–60.View ArticlePubMedGoogle Scholar
- Blazejczyk A, Papiernik D, Porshneva K, Sadowska J, Wietrzyk J. Endothelium and cancer metastasis: Perspectives for antimetastatic therapy. Pharmacol Rep. 2015;67:711–8.View ArticlePubMedGoogle Scholar
- Khorana AA. Cancer-associated thrombosis: updates and controversies. Hematology Am Soc Hematol Educ Program. 2012;2012:626–30.PubMedGoogle Scholar
- Placke T, Orgel M, Schaller M, Jung G, Rammensee HG, Kopp HG, Salih HR. Platelet-derived MHC class I confers a pseudonormal phenotype to cancer cells that subverts the antitumor reactivity of natural killer immune cells. Cancer Res. 2012;72:440–8.View ArticlePubMedGoogle Scholar
- Palumbo JS, Talmage KE, Massari JV, La Jeunesse CM, Flick MJ, Kombrinck KW, Jirouskova M, Degen JL. Platelets and fibrin(ogen) increase metastatic potential by impeding natural killer cell-mediated elimination of tumor cells. Blood. 2005;105:178–85.View ArticlePubMedGoogle Scholar
- Bendas G, Borsig L. Cancer cell adhesion and metastasis: selectins, integrins, and the inhibitory potential of heparins. Int J Cell Biol. 2012;2012:676731.View ArticlePubMedPubMed CentralGoogle Scholar
- Kispert SE, Marentette JO, McHowat J. Enhanced breast cancer cell adherence to the lung endothelium via PAF acetylhydrolase inhibition: a potential mechanism for enhanced metastasis in smokers. Am J Physiol Cell Physiol. 2014;307:C951–6.View ArticlePubMedPubMed CentralGoogle Scholar
- Gebremeskel S, LeVatte T, Liwski RS, Johnston B, Bezuhly M. The reversible P2Y12 inhibitor ticagrelor inhibits metastasis and improves survival in mouse models of cancer. Int J Cancer. 2015;136:234–40.View ArticlePubMedGoogle Scholar
- Toliopoulos IK, Simos YV, Daskalou TA, Verginadis II, Evangelou AM, Karkabounas SC. Inhibition of platelet aggregation and immunomodulation of NK lymphocytes by administration of ascorbic acid. Indian J Exp Biol. 2011;49:904–8.PubMedGoogle Scholar
- Algra AM, Rothwell PM. Effects of regular aspirin on long-term cancer incidence and metastasis: a systematic comparison of evidence from observational studies versus randomised trials. Lancet Oncol. 2012;13:518–27.View ArticlePubMedGoogle Scholar
- Mezouar S, Darbousset R, Dignat-George F, Panicot-Dubois L, Dubois C. Inhibition of platelet activation prevents the P-selectin and integrin-dependent accumulation of cancer cell microparticles and reduces tumor growth and metastasis in vivo. Int J Cancer. 2015;136:462–75.View ArticlePubMedGoogle Scholar
- Yoshida N, Yoshikawa T, Nakagawa S, Sakamoto K, Nakamura Y, Naito Y, Kondo M. Effect of shear stress and a stable prostaglandin I2 analogue on adhesive interactions of colon cancer cells and endothelial cells. Clin Exp Immunol. 1999;117:430–4.View ArticlePubMedPubMed CentralGoogle Scholar
- Daneker GW, Lund SA, Caughman SW, Staley CA, Wood WC. Anti-metastatic prostacyclins inhibit the adhesion of colon carcinoma to endothelial cells by blocking E-selectin expression. Clin Exp Metastasis. 1996;14:230–8.PubMedGoogle Scholar
- Schirner M, Schneider MR. Cicaprost inhibits metastases of animal tumors. Prostaglandins. 1991;42:451–61.View ArticlePubMedGoogle Scholar
- Schirner M, Schneider MR. The prostacyclin analogue cicaprost inhibits metastasis of tumours of R 3327 MAT Lu prostate carcinoma and SMT 2A mammary carcinoma. J Cancer Res Clin Oncol. 1992;118:497–501.View ArticlePubMedGoogle Scholar
- Sava G, Perissin L, Zorzet S, Piccini P, Giraldi T. Antimetastatic action of the prostacyclin analog iloprost in the mouse. Clin Exp Metastasis. 1989;7:671–8.View ArticlePubMedGoogle Scholar
- Milczarek M, Filip-Psurska B, Swietnicki W, Kutner A, Wietrzyk J. Vitamin D analogs combined with 5-fluorouracil in human HT-29 colon cancer treatment. Oncol Rep. 2014;32:491–504.PubMedPubMed CentralGoogle Scholar
- Mateuszuk L, Jasztal A, Maslak E, Gasior-Glogowska M, Baranska M, Sitek B, Kostogrys R, Zakrzewska A, Kij A, Walczak M, Chlopicki S. Antiatherosclerotic Effects of 1-Methylnicotinamide in Apolipoprotein E/Low-Density Lipoprotein Receptor-Deficient Mice: A Comparison with Nicotinic Acid. J Pharmacol Exp Ther. 2016;356:514–24.View ArticlePubMedGoogle Scholar
- Tzanakakis GN, Agarwal KC, Vezeridis MP. Inhibition of hepatic metastasis from a human pancreatic adenocarcinoma (RWP-2) in the nude mouse by prostacyclin, forskolin, and ketoconazole. Cancer. 1990;65:446–51.View ArticlePubMedGoogle Scholar
- Nojiri T, Hosoda H, Tokudome T, Miura K, Ishikane S, Otani K, Kishimoto I, Shintani Y, Inoue M, Kimura T, et al. Atrial natriuretic peptide prevents cancer metastasis through vascular endothelial cells. Proc Natl Acad Sci U S A. 2015;112:4086–91.View ArticlePubMedPubMed CentralGoogle Scholar
- Yoshitomi Y, Nakanishi H, Kusano Y, Munesue S, Oguri K, Tatematsu M, Yamashina I, Okayama M. Inhibition of experimental lung metastases of Lewis lung carcinoma cells by chemically modified heparin with reduced anticoagulant activity. Cancer Lett. 2004;207:165–74.View ArticlePubMedGoogle Scholar
- Weidner N, Semple JP, Welch WR, Folkman J. Tumor angiogenesis and metastasis--correlation in invasive breast carcinoma. N Engl J Med. 1991;324:1–8.View ArticlePubMedGoogle Scholar
- Aburakawa Y, Kawabe J, Okada M, Yamauchi A, Asanome A, Kabara M, Matsuki M, Takehara N, Nakagawa N, Okumura S, et al. Prostacyclin stimulated integrin-dependent angiogenic effects of endothelial progenitor cells and mediated potent circulation recovery in ischemic hind limb model. Circ J. 2013;77:1053–62.View ArticlePubMedGoogle Scholar
- Limjeerajarus CN, Osathanon T, Manokawinchoke J, Pavasant P. Iloprost up-regulates vascular endothelial growth factor expression in human dental pulp cells in vitro and enhances pulpal blood flow in vivo. J Endod. 2014;40:925–30.View ArticlePubMedGoogle Scholar
- Peshavariya HM, Liu GS, Chang CW, Jiang F, Chan EC, Dusting GJ. Prostacyclin signaling boosts NADPH oxidase 4 in the endothelium promoting cytoprotection and angiogenesis. Antioxid Redox Signal. 2014;20:2710–25.View ArticlePubMedGoogle Scholar
- Osawa T, Ohga N, Hida Y, Kitayama K, Akiyama K, Onodera Y, Fujie M, Shinohara N, Shindoh M, Nonomura K, Hida K. Prostacyclin receptor in tumor endothelial cells promotes angiogenesis in an autocrine manner. Cancer Sci. 2012;103:1038–44.View ArticlePubMedGoogle Scholar
- Chauhan VP, Stylianopoulos T, Martin JD, Popović Z, Chen O, Kamoun WS, Bawendi MG, Fukumura D, Jain RK. Normalization of tumour blood vessels improves the delivery of nanomedicines in a size-dependent manner. Nat Nanotechnol. 2012;7:383–8.View ArticlePubMedPubMed CentralGoogle Scholar
- Li X, Padhan N, Sjostrom EO, Roche FP, Testini C, Honkura N, Sainz-Jaspeado M, Gordon E, Bentley K, Philippides A, et al. VEGFR2 pY949 signalling regulates adherens junction integrity and metastatic spread. Nat Commun. 2016;7:11017.View ArticlePubMedGoogle Scholar
- Larue L, Bellacosa A. Epithelial-mesenchymal transition in development and cancer: role of phosphatidylinositol 3' kinase/AKT pathways. Oncogene. 2005;24:7443–54.View ArticlePubMedGoogle Scholar
- Buonato JM, Lazzara MJ. ERK1/2 blockade prevents epithelial-mesenchymal transition in lung cancer cells and promotes their sensitivity to EGFR inhibition. Cancer Res. 2014;74:309–19.View ArticlePubMedGoogle Scholar
- Shi M, Chen D, Yang D, Liu XY. CCL21-CCR7 promotes the lymph node metastasis of esophageal squamous cell carcinoma by up-regulating MUC1. J Exp Clin Cancer Res. 2015;34:149.View ArticlePubMedPubMed CentralGoogle Scholar
- Fei F, Zhang D, Yang Z, Wang S, Wang X, Wu Z, Wu Q, Zhang S. The number of polyploid giant cancer cells and epithelial-mesenchymal transition-related proteins are associated with invasion and metastasis in human breast cancer. J Exp Clin Cancer Res. 2015;34:158.View ArticlePubMedPubMed CentralGoogle Scholar
- Xu C, Hua F, Chen Y, Huang H, Ye W, Yu Y, Shen Z. MTA1 promotes metastasis of MPM via suppression of E-cadherin. J Exp Clin Cancer Res. 2015;34:151.View ArticlePubMedPubMed CentralGoogle Scholar
- Masclee GM, Valkhoff VE, Coloma PM, de Ridder M, Romio S, Schuemie MJ, Herings R, Gini R, Mazzaglia G, Picelli G, et al. Risk of upper gastrointestinal bleeding from different drug combinations. Gastroenterology. 2014;147:784–92.View ArticlePubMedGoogle Scholar
- Naruse Y, Sato A, Hoshi T, Takeyasu N, Kakefuda Y, Ishibashi M, Misaki M, Abe D, Aonuma K. Triple antithrombotic therapy is the independent predictor for the occurrence of major bleeding complications: analysis of percent time in therapeutic range. Circ Cardiovasc Interv. 2013;6:444–51.View ArticlePubMedGoogle Scholar
- Yasuda H, Matsuo Y, Sato Y, Ozawa S-i, Ishigooka S, Yamashita M, Yamamoto H, Itoh F. Treatment and prevention of gastrointestinal bleeding in patients receiving antiplatelet therapy. World J Crit Care Med. 2015;4:40–6.View ArticlePubMedPubMed CentralGoogle Scholar
- Majed BH, Khalil RA. Molecular mechanisms regulating the vascular prostacyclin pathways and their adaptation during pregnancy and in the newborn. Pharmacol Rev. 2012;64:540–82.View ArticlePubMedPubMed CentralGoogle Scholar
- Hong S, Moreno-Navarrete JM, Wei X, Kikukawa Y, Tzameli I, Prasad D, Lee Y, Asara JM, Fernandez-Real JM, Maratos-Flier E, Pissios P. Nicotinamide N-methyltransferase regulates hepatic nutrient metabolism through Sirt1 protein stabilization. Nat Med. 2015;21:887–94.View ArticlePubMedPubMed CentralGoogle Scholar
- Chen C, Wang X, Huang X, Yong H, Shen J, Tang Q, Zhu J, Ni J, Feng Z. Nicotinamide N-methyltransferase: a potential biomarker for worse prognosis in gastric carcinoma. Am J Cancer Res. 2016;6:649–63.PubMedPubMed CentralGoogle Scholar
- Parsons RB, Aravindan S, Kadampeswaran A, Evans EA, Sandhu KK, Levy ER, Thomas MG, Austen BM, Ramsden DB. The expression of nicotinamide N-methyltransferase increases ATP synthesis and protects SH-SY5Y neuroblastoma cells against the toxicity of Complex I inhibitors. Biochem J. 2011;436:145–55.View ArticlePubMedGoogle Scholar
- Bi HC, Pan YZ, Qiu JX, Krausz KW, Li F, Johnson CH, Jiang CT, Gonzalez FJ, Yu AM. N-methylnicotinamide and nicotinamide N-methyltransferase are associated with microRNA-1291-altered pancreatic carcinoma cell metabolome and suppressed tumorigenesis. Carcinogenesis. 2014;35:2264–72.View ArticlePubMedPubMed CentralGoogle Scholar
- Sartini D, Santarelli A, Rossi V, Goteri G, Rubini C, Ciavarella D, Lo Muzio L, Emanuelli M. Nicotinamide N-methyltransferase upregulation inversely correlates with lymph node metastasis in oral squamous cell carcinoma. Mol Med. 2007;13:415–21.View ArticlePubMedPubMed CentralGoogle Scholar
- Zhou W, Gui M, Zhu M, Long Z, Huang L, Zhou J, He L, Zhong K. Nicotinamide -methyltransferase is overexpressed in prostate cancer and correlates with prolonged progression-free and overall survival times. Oncol Lett. 2014;8:1175–80.PubMedPubMed CentralGoogle Scholar
- Ulanovskaya OA, Zuhl AM, Cravatt BF. NNMT promotes epigenetic remodeling in cancer by creating a metabolic methylation sink. Nat Chem Biol. 2013;9:300–6.View ArticlePubMedPubMed CentralGoogle Scholar
- Aksoy S, Szumlanski CL, Weinshilboum RM. Human liver nicotinamide N-methyltransferase. cDNA cloning, expression, and biochemical characterization. J Biol Chem. 1994;269:14835–40.PubMedGoogle Scholar
- Wang T, Cui H, Ma N, Jiang Y. Nicotinamide-mediated inhibition of SIRT1 deacetylase is associated with the viability of cancer cells exposed to antitumor agents and apoptosis. Oncol Lett. 2013;6:600–4.PubMedPubMed CentralGoogle Scholar
- Audrito V, Vaisitti T, Rossi D, Gottardi D, D'Arena G, Laurenti L, Gaidano G, Malavasi F, Deaglio S. Nicotinamide blocks proliferation and induces apoptosis of chronic lymphocytic leukemia cells through activation of the p53/miR-34a/SIRT1 tumor suppressor network. Cancer Res. 2011;71:4473–83.View ArticlePubMedGoogle Scholar