Fig. 2

Circ-MTHFD1L is crucial for maintaining gemcitabine resistance. A Quantitative RT-PCR (qRT-PCR) analysis of circ-MTHFD1L in the two gemcitabine-resistant cell lines compared with their parental cells. B Three knockdown sequences were designed to target the circ-MTHFD1L junction site C-D The overexpression and knockdown efficiency of circ-MTHFD1L were confirmed by qRT-PCR analysis of circ-MTHFD1L and MTHFD1L mRNA in PANC-1-GR. E-H The proliferative ability of stably transfected PANC-1-GR or BxPC-3-GR cells dealing with gemcitabine was investigated via colony formation assays (E, F) and CCK-8 assays (cell viability and IC50) (G, H). Representative colony formation images are shown (E), and the numbers of colonies were summarized (F). I Flow cytometry analysis of the cell cycle progression of stably transfected PANC-1-GR or BxPC-3-GR cells dealing with gemcitabine was performed. Representative images and quantification of the results are presented. Data are shown as mean ± SD. *P < 0.05; **P < 0.01; ***P < 0.001, between the indicated groups