Eicosapentaenoic acid enhances the sensitivity of bladder cancer cell line T24 to cisplatin via inhibiting autophagy reaction

Objective To investigate the effect and underlying mechanism of eicosapentaenoic acid (EPA) on the sensitivity of bladder cancer cell line T24 to cisplatin. Methods T24 cells were randomly divided into five groups: control group, EPA group, cisplatin group (group DDP), EPA+ DDP group and rapamycin group (group EPA+ Rapa+ DDP). Cell counting Kit-8 (CCK-8) method was used to evaluate inhibition ratio of cell proliferation. The apoptotic ratio was examined by flow eytometry (FCM). The protein expressions of apoptosis cytokines [cysteine-containing aspartate-specific proteases (Cleaved Caspase)-3, B cell lymphoma/leukemia-2 associated X protein (bax), B cell lymphoma/leukemia-2 (bcl-2)] and autophagy reaction cytokines (LC3-Ⅱ, Beclin-1) were detected by Western blotting. Results Compared to DDP treatment alone, the proliferation inhibition ratio and apoptotic ratio of T24 cells were enhanced by EPA+ DDP treatment [(73.19±6.92)% vs. (48.62±4.80)%, P=0.000; (64.30±6.53)% vs. (35.90±4.21)%, P=0.010, respectively]; Western blotting showed that the expressions of apoptotic factors were increased by EPA+ DDP treatment. Meanwhile, the protein expressions of bcl-2, LC3-Ⅱ and Beclin-1 were significantly inhibited by EPA+ DDP treatment (P=0.000). However, the salutary effects of EPA would been reversed by autophagy reaction activation rapamycin. Conclusion EPA enhances the sensitivity of bladder cancer cell line T24 to cisplatin, which may suppress activation of autophagy reaction. Key words: Bladder cancer cells; Eicosapentaenoic acid; Cisplatin; Autophagy reaction