环状RNA001380通过miR-30b诱导KRAS野生型结直肠癌患者西妥昔耐药的机制研究

Previous studies showed that miR-30b could inhibit the proliferation of colorectal cancer cells by combining with KRAS. Pre-experiment suggested that circ-001380 could bind to miR-30b. The expression of circ-001380 in tissue samples was opposite to that of miR-30b.While the expression of circ001380 is consistent with KRAS’s expression. In order to demonstrate that circ-001380 could induce wild-type KRAS patients cetuximab-resistant by targeting miR-30b.We further constructed cell models in EGFR-positive and wild-type KRAS colorectal cancer cell lines. The mechanism of circ-001380 and miR-30b was studied by molecular experiments, cell experiments and visualization of colon cancer in situ transplantation in EGFR-positive and wild-type KRAS colorectal cancer cell lines. Meanwhile, we will detect the expression of KRAS, the KRAS signal pathway and the Cetuxine resistance on colon cancer cells. We will explore the mechanism of Cetuxine resistance on wild-type KRAS colorectal cancer cells by circ-001380 and miR-30b. Finally find the effective molecular marker for wild-type KRAS CRC patients with cetirizine resistance.

前期研究发现miR-30b通过与KRAS结合可以抑制结直肠癌细胞的增殖能力，预实验提示circ-001380与miR-30b可结合，组织标本中circ-001380的表达与miR-30b表达趋势相反，与KRAS表达趋势一致；为了证实circ-001380通过miR-30b诱导KRAS野生型细胞西妥昔耐药，我们将在EGFR阳性且KRAS野生型的细胞中构建模型，结合分子、细胞及动物原位移植模型研究circ-001380及miR-30b的作用机制及二者对细胞功能的影响，对KRAS基因表达的影响、对KRAS下游信号通路的影响以及对结直肠癌细胞西妥昔耐药的影响；为结直肠癌KRAS野生型患者西妥耐药寻找有效的分子标志物及治疗靶标。

结直肠癌严重威胁着人类生命健康，在精准医学的时代背景下，分子靶向治疗已经成为肿瘤治疗的重要手段，结直肠癌的"精准医学"就是在癌症基因组测序和信息分析基础上,解析结直肠癌发生、发展、侵袭、转移和复发的机制,有针对性地实施个体化治疗。作为第一个全球多个国家获准上市的靶向药物西妥昔单抗，在分子水平干预肿瘤细胞的生长，它特异性高，副作用小，与传统化疗药物连用少有毒性叠加，在临床上得到了广泛的应用，但是部分患者对西妥昔产生耐药。本项目研究发现circ_IFNGR2可以通过miR-30b诱导野生型KRAS结直肠癌患者出现西妥昔耐药。我们在组织标本中检测发circ_IFNGR2的表达与miR-30b表达趋势相反，与KRAS表达趋势一致；荧光定量PCR、双荧光素酶报告实验及FISH试验证实了circ_IFNGR2可以与miR-30b结合，进一步上调野生型KRAS的表达；细胞功能实验证实circ_IFNGR2可以促进结直肠癌细胞增殖及迁移，并且circ_IFNGR2通过与miR-30b结合，诱导KRAS野生型细胞西妥昔耐药。通过这一系列的实验，我们明确了circ_IFNGR2可以促进结直肠癌细胞的增殖及侵袭；circ_IFNGR2可以通过miR-30b“释放”KRAS，从而激活KRAS相关信号通路；进一步介导结直肠癌细胞发生西妥昔耐药；临床标本中初步提示circ_IFNGR2可以作为西妥昔耐药的分子指标。本项目积极探索结直肠癌患者对西妥昔耐药的分子机制，寻找西妥昔治疗有效的分子标志物，以期为患者的"个体化"精准医疗提供新思路及新靶标。