Fig. 1

High expression of CDA and TYMP associates with chemoresistance and sensitivity to 5′-DFCR. a Pyrimidine pathway, CDA (cytidine deaminase) and TYMP (thymidine phosphorylase) are key enzymes in pyrimidine salvage pathway; b High expression of CDA and TYMP sensitized A549 paraclone cells to 5′-DFCR. Left, APH cell viability assay, right, colony formation assay; c CDA inhibition rescued A549 para clone cells from the sensitivity to 5′-DFCR, left APH cell viability assay; right, colony formation assay. d Immunoblotting of CDA and TYMP in different A549 subpopulations P: parental A549; Holo, Mero and Para represent A549 holo, mero and para clone cells, respectively. Ordinary two-way ANOVA was used for significance anlysis of drug response curves (Fig. 1b/e/j/k, ****P < .0001). A two-sided t-test was used for the significance anlysis of the CDA activity assay (Fig. 1h, **P < .01)