Department of Pharmacy, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
Fundam Clin Pharmacol. 2021 Aug;35(4):690-699. doi: 10.1111/fcp.12608. Epub 2020 Dec 5.
Hepatocellular carcinoma (HCC) is one of the most common lethal human malignancies worldwide. Sorafenib is the first-line drug approved by the United States Food and Drug Administration for HCC. However, the acquired resistance to sorafenib reduces its beneficial effects and limits clinical use. In this study, we established a sorafenib-resistant HCC cell line HepG2-SR by low-concentration gradient induction. Compared with the parental cell HepG2, the proliferation and anti-apoptosis were increased in drug-resistant cell HepG2-SR. Thorough comparisons of the molecular changes between parental HepG2 and sorafenib-resistant HepG2-SR cells indicated that the Notch signaling pathway and PI3K/Akt signaling pathway were associated with sorafenib resistance mechanisms. Notch1 and Akt were upregulated in sorafenib-resistant cells. However, we surprisingly found that valproic acid (VPA) combined with sorafenib could enhance the sensitivity of drug-resistant cells and reverse the increased levels of Notch1 and Akt in sorafenib-resistant HCC cells. Moreover, Akt inhibitor could suppress Notch1 expression, whereas the level of Akt phosphorylation decreased along with increasing dose of Notch inhibitor. Besides, we found that knockdown of Akt resulted in Notch1 reduction, whereas Notch1 reduction also led to a significant reduction in the phosphorylation of Akt. Collectively, our results indicated that Notch1 and Akt might play vital roles in sorafenib resistance in HCC cells and VPA might overcome the drug resistance to enhance the sensitivity of HCC cells to sorafenib through suppressing Notch/Akt signaling pathway. VPA combined with sorafenib may provide a potential targeting therapeutic regimen for clinically to solve the problem of sorafenib resistance.
肝细胞癌（HCC）是全球最常见的致命人类恶性肿瘤之一。索拉非尼是美国食品和药物管理局批准用于 HCC 的一线药物。然而，对索拉非尼的获得性耐药降低了其有益效果并限制了临床应用。在这项研究中，我们通过低浓度梯度诱导建立了索拉非尼耐药 HCC 细胞系 HepG2-SR。与亲本细胞 HepG2 相比，耐药细胞 HepG2-SR 的增殖和抗凋亡能力增强。亲本 HepG2 和索拉非尼耐药 HepG2-SR 细胞之间的分子变化的彻底比较表明，Notch 信号通路和 PI3K/Akt 信号通路与索拉非尼耐药机制有关。Notch1 和 Akt 在耐药细胞中上调。然而，我们惊讶地发现，丙戊酸（VPA）与索拉非尼联合使用可以增强耐药细胞的敏感性，并逆转索拉非尼耐药 HCC 细胞中 Notch1 和 Akt 的增加水平。此外，Akt 抑制剂可以抑制 Notch1 的表达，而 Notch 抑制剂剂量增加时，Akt 磷酸化水平降低。此外，我们发现 Akt 的敲低导致 Notch1 的减少，而 Notch1 的减少也导致 Akt 磷酸化的显著减少。总之，我们的结果表明，Notch1 和 Akt 可能在 HCC 细胞中对索拉非尼耐药起关键作用，VPA 可能通过抑制 Notch/Akt 信号通路克服耐药性，从而增强 HCC 细胞对索拉非尼的敏感性。VPA 联合索拉非尼可能为临床上解决索拉非尼耐药问题提供一种潜在的靶向治疗方案。
