Wild type Kirsten rat sarcoma is a novel microRNA-622-regulated therapeutic target for hepatocellular carcinoma and contributes to sorafenib resistance
Wild type Kirsten rat sarcoma is a novel microRNA-622-regulated therapeutic target for hepatocellular carcinoma and contributes to sorafenib resistance
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DOI：
10.1136/gutjnl-2017-315402
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发表时间：
2018-07-01
期刊：
影响因子：
24.5
通讯作者：
Hellerbrand, Claus
中科院分区：
文献类型：
--
作者：
Dietrich, Peter;Koch, Andreas;Hellerbrand, Claus
目的索拉非尼是治疗晚期肝细胞癌的唯一有效方法。针对丝裂原活化蛋白激酶/细胞外信号调节激酶和phosphatidylinositol-4，5-bisphosphate-3-kinase(PI3K)/蛋白激酶B(AKT)信号的联合方法产生了重大的治疗改进。RAS蛋白调节RAF/MAPK和PI3K/AKT信号转导。然而，在致癌过程中最重要的RAS亚型Kirsten鼠肉瘤(KRAS)在肝癌中仍未被探索。设计采用人类肝癌组织和细胞系进行表达和功能分析。新生的肝癌细胞对索拉非尼耐药。结果野生型KRAS信使RNA和蛋白在肝癌组织中的表达增加，并与细胞外信号调节激酶(ERK)的激活、增殖率、肿瘤的进展和患者的生存不良有关。生物信息学分析和报告分析表明，KRAS是microRNA-622的直接靶标。这种microRNA在肝细胞癌中表达下调，功能分析表明KRAS抑制是其抑制肝细胞癌增殖作用的主要介质。KRAS抑制明显抑制RAF/ERK和PI3K/AKT信号转导和增殖，促进体内外肝癌细胞的凋亡。联合应用KRAS抑制和索拉非尼治疗显示出协同抗肝癌作用。对索拉非尼耐药的肝癌细胞显示KRAS表达升高，抑制KRAS使耐药细胞对抑制增殖和诱导细胞凋亡变得更加敏感。结论KRAS在肝细胞癌中通过丢失抑瘤基因microRNA-622而失控，参与了肿瘤的进展、对索拉非尼的敏感性和耐药性。单独或与索拉非尼联合抑制KRAS似乎是治疗肝癌的新的有希望的治疗策略。
Objective Sorafenib is the only effective therapy for advanced hepatocellular carcinoma (HCC). Combinatory approaches targeting mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK)-and phosphatidylinositol-4,5-bisphosphate-3-kinase (PI3K)/protein-kinase B(AKT) signalling yield major therapeutic improvements. RAS proteins regulate both RAF/MAPK and PI3K/AKT signalling. However, the most important RAS isoform in carcinogenesis, Kirsten rat sarcoma (KRAS), remains unexplored in HCC.Design Human HCC tissues and cell lines were used for expression and functional analysis. Sorafenib-resistant HCC cells were newly generated. RNA interference and the novel small molecule deltarasin were used for KRAS inhibition both in vitro and in a murine syngeneic orthotopic HCC model.Results E xpression of wild type KRAS messenger RNA and protein was increased in HCC and correlated with extracellular-signal regulated kinase (ERK) activation, proliferation rate, advanced tumour size and poor patient survival. Bioinformatic analysis and reporter assays revealed that KRAS is a direct target of microRNA-622. This microRNA was downregulated in HCC, and functional analysis demonstrated that KRAS-suppression is the major mediator of its inhibitory effect on HCC proliferation. KRAS inhibition markedly suppressed RAF/ERK and PI3K/AKT signalling and proliferation and enhanced apoptosis of HCC cells in vitro and in vivo. Combinatory KRAS inhibition and sorafenib treatment revealed synergistic antitumorigenic effects in HCC. Sorafenib-resistant HCC cells showed elevated KRAS expression, and KRAS inhibition resensitised sorafenibresistant cells to suppression of proliferation and induction of apoptosis.Conclusions KRAS is dysregulated in HCC by loss of tumour-suppressive microRNA-622, contributing to tumour progression, sorafenib sensitivity and resistance. KRAS inhibition alone or in combination with sorafenib appears as novel promising therapeutic strategy for HCC.