RASSF6逆转肾透明细胞癌细胞对索拉非尼治疗耐受的现象及分子机制

Clear cell renal cell carcinoma (ccRCC) is a highly aggressive and common pathological subtype of renal cancer. This cancer is characterized by biallelic inactivation of the von Hippel–Lindau (VHL) tumor suppressor gene, which leads to the accumulation of hypoxia-inducible factors (HIFs). Sorafenib that target at VHL-HIFs is commonly used as first/second-line treatment in advanced ccRCC. It is not rare patients eventually succumb to the disease owing to sorafenib resistance. Studies are urgently needed to elucidate the mechanism of sorafenib resistance in ccRCC. Our previous study has confirmed RASSF6 was a novel tumor suppressor that played an important role in the pathogenesis of ccRCC. Further study suggested RASSF6 regulated sorafenib sensitivity in both VHL-mutant and -wide-type ccRCC cells by triggering JNK and HIPPO pathways. Our proposal will be to identify the role and mechanisms of RASSF6 in reversing resistance to sorafenib in ccRCC. The role of RASSF6 in cell survival, cell cycle arrest and apoptosis with sorafenib treatment will be investigated in vitro and in vivo. Moreover, the relationship between RASSF6 and sorafenib treatment response will also be evaluated in clinical ccRCC samples. Mechanism analysis will confirm whether RASSF6 regulate JNK and HIPPO pathways; determine whether the role of RASSF6 is VHL-independent. Our proposal will define a central role for RASSF6 in sorafenib resistance and suggest its use in predicting sorafenib treatment response in ccRCC.

索拉非尼是肾透明细胞癌的重要一/二线靶向药物，然而，绝大多数患者最终都出现对索拉非尼的耐药，其机制未明。我们已证实RASSF6抑制肾透明细胞癌发生，成果已发表SCI论文。进一步研究提示RASSF6瞬时表达影响VHL突变/野生型肾癌细胞对索拉非尼的反应，并调控JNK及HIPPO信号通路活性。我们因此提出一个科学假说：RASSF6通过调控JNK及HIPPO信号通路逆转肾透明细胞癌对索拉非尼的耐药，且不依赖VHL基因突变。本研究将从多个层面阐明该假说：在体内、外实验中验证RASSF6调控索拉非尼处理的生物学效应，并评价人体肾癌标本中RASSF6与索拉非尼临床敏感性相关。机制研究利用通路分析明确JNK及HIPPO通路激活情况，利用VHL野生/突变型细胞探索RASSF6作用是否依赖于VHL。本项目的完成将为临床上预测索拉非尼治疗肾癌的疗效提供新的分子靶标，为实现索拉非尼的个体化治疗奠定基础。

肿瘤耐药及肿瘤转移等恶性行为的分子机制尚未充分明了。前期发现RASSF6抑制肾透明细胞癌发生，RASSF6过表达增加肾癌细胞对索拉非尼的反应，抑制RASSF6表达则减轻索拉非尼在肾癌细胞中的杀伤作用，体外诱导的索拉非尼耐药细胞株中RASSF6的表达也明显上调。RASSF6通过激活JNK信号通路活性抑制MCL-1蛋白表达，从而增加细胞凋亡。同时动物体内实验中也进一步验证RASSF6调控索拉非尼治疗的生物学效应，并评价人体肾癌标本中RASSF6与索拉非尼临床敏感性正相关并且MCL-1表达负相关。本项目的完成提示RASSF6为临床上预测索拉非尼治疗肾癌的疗效提供新的分子靶标，为实现索拉非尼的个体化治疗奠定基础。与此同时发现RASSF6通过ＪＮＫ／ＳＡＰＫ 通路增加干扰素引起的凋亡激活逆转肾癌细胞对干扰素的抵抗，Ras相关区域家族1A(RASSF1A) 逆转鼻咽癌细胞对顺铂的抵抗。全基因组 cDNA 表达谱芯片筛选CLCA2在鼻咽癌标本表达下降。是鼻咽癌不良预后指标。miR-381 在肾细胞癌( 肾癌) 细胞系中的表达变化，及其对肾癌细胞增殖、迁移、侵袭能力的影响。项目资助发表SCI论文2篇，在投SCI文章2篇，中文核心论文3篇，培养研究生1名，已经取得硕士学位。项目投入经费18万元，支出17.99万元，各项支出基本与预算相符。