BACKGROUND Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Phloretin (PH) possesses anticancer, antitumor, and hepatoprotective effects, however, the effects and potential mechanisms of phloretin remain elusive. METHODS Five HCC cells were tested in vitro for sensitivity to PH, Sorafenib (Sor) or both and the apoptosis, signal transduction and phosphatase activity were analyzed. To validate the role of SHP-1, we used PTP inhibitor III and SHP-1 siRNA. Further, we used purified SHP-1 proteins or HCC cells expressing deletion N-SH2 domain or D61A point mutants to study the PH efficacy on SHP-1. The `in vivo studies were conducted using HepG2 and SK-Hep1 and Sor resistant HepG2SR and Huh7SR xenografts. Molecular docking was done with Swiss dock and Auto Dock Vina. RESULTS PH inhibited cell growth and induced apoptosis in all HCC cells by upregulating SHP-1 expression and downregulating STAT3 expression and further inhibited pAKT/pERK signaling. PH activated SHP-1 by disruption of autoinhibition of SHP-1, leading to reduced p-STAT3Tyr705 level. PH induced apoptosis in two Sor-resistant cell lines and overcome STAT3, AKT, MAPK and VEGFR2 dependent Sor resistance in HCCs. PH potently inhibited tumor growth in both Sor-sensitive and Sor-resistant xenografts in vivo by impairing angiogenesis, cell proliferation and inducing apoptosis via targeting the SHP-1/STAT3 signaling pathway. CONCLUSION Our data suggest that PH inhibits STAT3 activity in Sor-sensitive and -resistant HCCs via SHP-1-mediated inhibition of STAT3 and AKT/mTOR/JAK2/VEGFR2 pathway. Our results clearly indicate that PH may be a potent reagent for hepatocellular carcinoma and a noveltargeted therapy for further clinical investigations.

中文翻译：

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荧光素减弱肝细胞癌中STAT-3的活性并克服针对SHP-1介导的STAT3和Akt / VEGFR2途径抑制作用的索拉非尼耐药。

背景技术肝细胞癌（HCC）是最常见的原发性肝恶性肿瘤。Phloretin（PH）具有抗癌，抗肿瘤和肝保护作用，但是，phloretin的作用和潜在机制仍然难以捉摸。方法在体外测试五种HCC细胞对PH，索拉非尼（Sor）或两者的敏感性，并分析其凋亡，信号转导和磷酸酶活性。为了验证SHP-1的作用，我们使用了PTP抑制剂III和SHP-1 siRNA。此外，我们使用表达缺失N-SH2结构域或D61A点突变体的纯化SHP-1蛋白或HCC细胞来研究PH对SHP-1的功效。使用HepG2和SK-Hep1以及耐Sor的HepG2SR和Huh7SR异种移植进行了体内研究。分子对接是通过Swiss Dock和Auto Dock Vina完成的。结果PH通过上调SHP-1表达和下调STAT3表达来抑制所有HCC细胞的生长并诱导其凋亡，并进一步抑制pAKT / pERK信号传导。PH通过破坏SHP-1的自抑制作用激活SHP-1，从而导致p-STAT3Tyr705水平降低。PH诱导了两种Sor抗性细胞系的凋亡，并克服了HCC中STAT3，AKT，MAPK和VEGFR2依赖性Sor抗性。PH通过靶向SHP-1 / STAT3信号通路来削弱血管生成，细胞增殖并诱导凋亡，从而在体内对Sor敏感和Sor耐药的异种移植物中均有效地抑制了肿瘤的生长。结论我们的数据表明PH通过SHP-1介导的STAT3和AKT / mTOR / JAK2 / VEGFR2途径的抑制作用来抑制Sor敏感和耐药HCC中的STAT3活性。