Fig. 6
Inhibition of miR-365-3p/KRT16/β5-integrin/c-Met signaling pathway in OSCC cells enhances chemosensitivity towards 5-FU treatment. a OC-3-IV cells were transfected with indicated plasmids for 48 h, and then were treated with various concentrations of 5-FU continuously for an additional 18 h. MTT assay was conducted to measure cell growth after 72 h. b Dose-dependent growth inhibitory effect on OC-3-IV cells or KRT16-depleted OC-3-IV cells upon continuous exposure to 5-FU as indicated concentration through MTT assay. c Top, dose-dependent growth inhibitory effect in OC-3-IV cells or KRT16-depleted OC-3-IV cells after continuous exposure to foretinib (a c-Met inhibitor) as indicated concentration through MTT assay. Bottom, KRT16 knockdown further sensitized OC-3-IV cells toward combined 5-FU and foretinib treatment. d Top, dose-dependent growth inhibitory effect in OC-3-IV cells or KRT16-depleted OC-3-IV cells after continuous exposure to genistein as indicated concentration through MTT assay. Bottom, KRT16 knockdown further sensitized OC-3-IV cells toward combined 5-FU and genistein treatment. e Combination treatment of 5-FU, foretinib, and ITGB5-ab markedly reduced tumor size in vivo. Left, CB17-SCID mice were categorized into five groups according to the treatment of compounds as indicated. In each group, 1 × 106 OC-3-IV cells were subcutaneously implanted into CB17-SCID mice separately. Right, tumor growth was monitored. All mice were sacrificed on day 56 after implantation. All the in vitro experiments were performed in triplicates and repeated three times (*P < 0.05, **P < 0.01). f The model of a novel miR-365-3p/EHF/KRT16/β5-integrin/c-Met cascade signaling pathway. KRT16 is associated with β5-integrin and c-Met with stabilization leading to enhanced c-Met signaling as well as activation of Src/STAT3 signaling to promote metastasis, cancer stemness, and drug resistance in OSCC cells. The dotted lines represent the protein degradation