调控HO-1表达对肿瘤耐药的逆转作用及机理研究

Resistance toward anti-cancer drugs in tumor is usually accompany with up-regulation of Heme Oxygenase-1 （HO-1）. In this study, various tumor cells lines resisted to chemotherapy, primary tumor stem cells and tumor-bearing mice were employed as research targets. lentivirus and the RNA interference technology plus inducer/inhibitor strategy combined with the gene transfer were used for the regulation of HO-1 expression. The primary results of our in-vitro study demonstrated that HO-1 was closely correlated with tumor drug-resistance in which multiple pathways were involved, and the down-regulation of HO-1 in ex-vivo experiment increased the sensitivity to chemotherapy. Then, gene-sequencing, protein-chip, real-time PCR high-throughput screening technology will be used in our following in-vitro study on the relationship between HO-1 and drug-resistance and also on the underlying mechanisms. In animal experiments, ELISA analysis will be taken for the detection of inflammatory molecule in tumor micro-environment, Hoechst tracing technology be used for chemotherapy sensitivity analysis, and immunohistochemistry be used for the expression analysis of HO-1 related pathways involved in drug-resistance, trying to elucidate the role of HO-1 as a potential therapeutic target for drug-resistance,down-regulating HO-1 might be able to reverse the drug-resistance,and to disclose the underlying mechanism. Accumulating experimental evidence for the study on drug-resistance in tumor therapy.

HO-1在肿瘤组织中多呈高表达常伴随化疗耐药。本项目以多种肿瘤耐药细胞株及肿瘤干细胞和荷瘤小鼠为研究对象。采用慢病毒介导转基因手段和RNA沉默并结合诱导剂/抑制剂靶向调控HO-1表达。体内外实验初步结果显示，HO-1与肿瘤耐药呈高度相关，其机制涉及多条通路，下调HO-1可在体内外实验中增强肿瘤化疗敏感性。下一步拟将采用基因测序，蛋白芯片和real-time PCR高通量筛选通路等手段在体外探索HO-1与耐药的关系及其发生机制；动物实验中采用ELISA分析体内肿瘤微环境中炎性因子的变化，Hoechst示踪肿瘤化疗敏感性，免疫组化分析与HO-1耐药相关通路蛋白表达情况，试证实HO-1可作为肿瘤耐药相关的潜在靶点，下调HO-1可以逆转耐药，并阐明其耐药机制，为临床克服肿瘤耐药提供实验依据。

肿瘤耐药的普遍存在是导致化疗失败，癌症死亡率高居不下的重要原因之一。而血红素加氧酶-1（HO-1）在多种肿瘤组织中的异常高表达，已成为目前抗肿瘤的研究热点之一。本课题组对调控HO-1表达对肿瘤耐药的逆转作用及机理研究进行了深入的研究。其相关内容包括：.1.抑制HO-1增加骨髓增生异常综合症（MDS）细胞增加地西他滨对P15的去甲基化水平。从而增加MDS的凋亡率，增加MDS细胞对地西他滨的敏感性。.2.HO-1通过影响ROS-线粒体-钙离子通道，导致急性髓系白血病细胞Kasumi-1对柔红霉素耐药。.3.小干扰RNA沉默HO-1增强低浓度5-氮杂胞苷，影响AZA对SKM-1细胞p16的去甲基化作用从而诱导SKM-1细胞凋亡。.4.HO-1通过 JNK/c-JUN 信号通路抑制急性髓系白血病（AML）细胞凋亡。.5.细胞钠-氢离子泵通过激活PKC-β/p38MAPK/HO-1信号转导通路促使慢性粒细胞白血病（CML）发生耐药。.6.HO-1通过抑制mTOR信号转导通路诱导自噬的发生，从而导致CML对伊马替.尼耐药。.7.IL-6-HO-1信号之间的相互作用与多发性骨髓瘤细胞（MM）对来那度胺耐药相关。.8.抑制HO-1增加弥漫大B细胞淋巴瘤对长春新碱敏感性。.9.缺氧诱导因子-1a（HIF-1a）靶基因VEGF，GLUT1和HO-1的表达与耐药性，肿瘤血管生成和转移相关。.综上所述，HO-1 是肿瘤耐药的潜在靶点，下调HO-1 及其耐药相关转导通路能够实现逆转耐药，为临床克服肿瘤耐药和研发靶点抑制剂或信号通路阻断剂提供理论依据。