Combination of anlotinib and gemcitabine promotes the G0/G1 cell cycle arrest and apoptosis of intrahepatic cholangiocarcinoma in vitro

Background Intrahepatic cholangiocarcinoma (ICC) is a malignant carcinoma with high rate of mortality. The current treatment is ineffective with poor survival time. Therefore, there is an urgent need for effective therapeutic drug regimens. The multi-target tyrosine kinase inhibitor (TKI) anlotinib has been approved for treating non-small cell lung cancer (NSCLC); however, the combined therapeutic regimen of anlotinib for ICC has not been investigated yet. This study aims to investigate the inhibitory effect of anlotinib and the mechanism of gemcitabine combination for ICC treatment. Methods Two ICC cell lines, HCCC-9810 and RBE cells, were used in this study. Cell Counting Kit-8 (CCK-8) was used to study the cell viability, and flow cytometry (FCM) was used to evaluate the apoptosis and cell cycle arrest. Compusyn software was used to calculate the combination index (CI) of anlotinib and gemcitabine. The protein expression rate of cleaved PARP/PARP and cleaved caspase-3/caspase-3 was detected by Western blotting. Results Our result showed that the anlotinib and gemcitabine combination significantly inhibits the growth of ICC cell lines. Compusyn software results showed that the combination regimen had an anti-tumor synergistic effect. FCM results showed that it promoted apoptosis. Moreover, it increased the protein expression rate of cleaved PARP/PARP and cleaved caspase-3/caspase-3. Finally, we found a synergistic anti-tumor effect by increasing G0/G1 cell cycle arrest. Conclusion The combination of anlotinib and gemcitabine can increase the anti-tumor effect and may be a potential therapeutic drug regimen in a clinical setting.