Background

Sorafenib is an oral multi-kinase inhibitor that was approved by the US Food and Drug Administration for the treatment of patients with advanced hepatocellular carcinoma (HCC). However, resistance to sorafenib is an urgent problem to be resolved to improve the therapeutic efficacy of sorafenib. As the activation of AKT/mTOR played a pivotal role in sorafenib resistance, we evaluated the effect of a dual mTOR complex 1/2 inhibitor Torin2 on overcoming the sorafenib resistance in HCC cells.

Methods

The sorafenib-resistant Huh7 and Hep3B cell lines were established from their parental cell lines. The synergistic effect of sorafenib and Torin2 on these cells was measured by cell viability assay and quantified using the Chou-Talalay method. Apoptosis induced by the combination of sorafenib and Torin2 and the alteration in the specific signaling pathways of interest were detected by Western blotting.

Results

Sorafenib treatment inversely inhibited AKT in parental but activated AKT in sorafenib-resistant Huh7 and Hep3B HCC cells, which underscores the significance of AKT activation. Torin2 and sorafenib synergistically suppressed the viability of sorafenib-resistant cells via apoptosis induction. Torin2 successfully suppressed the sorafenib-activated mTORC2-AKT axis, leading to the dephosphorylation of Ser136 in BAD protein, and increased the expression of total BAD, which contributed to the apoptosis in sorafenib-resistant HCC cells.

Conclusions

In this study, Torin2 and sorafenib showed synergistic cytostatic capacity in sorafenib-resistant HCC cells, via the suppression of mTORC2-AKT-BAD pathway. Our results suggest a novel strategy of drug combination for overcoming sorafenib resistance in HCC.

中文翻译：

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Torin2通过抑制肝细胞癌细胞中的mTORC2-AKT-BAD通路克服索拉非尼耐药

背景

索拉非尼是一种口服多激酶抑制剂，已被美国食品和药物管理局批准用于治疗晚期肝细胞癌 (HCC) 患者。然而，索拉非尼耐药是提高索拉非尼疗效亟待解决的问题。由于 AKT/mTOR 的激活在索拉非尼耐药中起关键作用，我们评估了双重 mTOR 复合物 1/2 抑制剂 Torin2 对克服 HCC 细胞索拉非尼耐药的影响。

方法

索拉非尼抗性 Huh7 和 Hep3B 细胞系是从它们的亲代细胞系建立的。索拉非尼和 Torin2 对这些细胞的协同作用通过细胞活力测定进行测量，并使用 Chou-Talalay 方法进行量化。通过蛋白质印迹检测由索拉非尼和 Torin2 组合诱导的细胞凋亡以及感兴趣的特定信号通路的改变。

结果

索拉非尼治疗反向抑制亲本中的 AKT，但在索拉非尼抗性 Huh7 和 Hep3B HCC 细胞中激活 AKT，这强调了 AKT 激活的重要性。Torin2 和索拉非尼通过诱导凋亡协同抑制索拉非尼耐药细胞的活力。Torin2 成功抑制了索拉非尼激活的 mTORC2-AKT 轴，导致 BAD 蛋白中 Ser136 的去磷酸化，并增加了总 BAD 的表达，这有助于索拉非尼耐药 HCC 细胞的凋亡。

结论

在这项研究中，Torin2 和索拉非尼通过抑制 mTORC2-AKT-BAD 通路，在索拉非尼耐药的 HCC 细胞中显示出协同的细胞抑制能力。我们的结果提出了一种新的药物组合策略，用于克服 HCC 中的索拉非尼耐药性。