miR-203在卵巢癌细胞转移中的功能研究

Ovarian cancer is one of the most common malignant tumors for women in China. The metastasis and recurrence of tumor is the main cause of death in patients suffered from ovarian cancer. In our previous study, we found that the expression of miR-203 was up-regulated in ovarian cancer samples. And the expression level of miR-203 was significant correlated with the metastasis and hierarchical of tumor. Further studies showed that expression of miR-203 targeted SPARC may play an important role in promoting tumor metastasis. But the specific mechanism that expression of miR-203 and SPARC promoting the metastasis of ovarian cancer is still unclear. In this study, ovarian cancer specimens will be firstly collected to verify the relationship between miR-203, SPARC and metastasis of ovarian cancer at tissue level. Secondly, a variety of ovarian cancer cells will be cultivated, the miR-203 and SPARC genes will be silenced or overexpressed by RNAi and gene transfection at the cellular level. The changes of expression of its downstream genes will be detected by Western blot, fluorescence quantitative RT-PCR and gene chip technology. The invasion and metastasis ability of cancer cells will be detected by Transwell and cell migration experiment. The role of miR-203 target to SPARC to promote the metastasis of ovarian cancer will be proved by tumor formation experiment in nude mice. The study will further elucidate the metastasis mechanism of ovarian cancer and can provide a new therapeutic target for ovarian cancer.

卵巢癌是我国女性常见的恶性肿瘤之一，转移、复发是卵巢癌病人死亡的主要原因。在前期的研究中，我们发现miR-203在卵巢癌样品中表达上调，并且miR-203的表达水平与肿瘤的转移和分级显著相关。进一步的研究显示miR-203的表达靶向SPARC发挥其促肿瘤转移的作用，但两者促卵巢癌转移的具体机制尚不清楚。本研究中，首先收集卵巢癌标本在组织水平上求证miR-203、SPARC与卵巢癌转移的关系。其次培养多种卵巢癌细胞，应用RNAi及基因转染技术在细胞水平上沉默或过表达miR-203、SPARC基因；应用Western blot、荧光定量RT-PCR和基因芯片等技术检测其下游基因的表达变化；应用Transwell和裸鼠尾静脉技术检测癌细胞转移侵袭能力的改变；利用MIR-203基因敲除小鼠模型研究其靶向SPARC对卵巢癌发生和转移的影响，以进一步阐明卵巢癌转移机制，且为其治疗提供新的靶点。

衰老对肿瘤发生具有重要的负调控作用。以前已有报道，miR-203在细胞衰老中具有重要功能，但是机制不明。在本研究中，我们发现激酶ITPKA在卵巢癌中表达下调，其表达水平与卵巢癌病人的生存显著正相关。在细胞生物学功能上，我们发现在卵巢癌细胞中过表达ITPKA促进肿瘤细胞衰老，抑制肿瘤细胞非锚定性生长及其在体内的成瘤能力。干扰ITPKA在卵巢癌细胞中的表达抑制肿瘤细胞衰老，促进肿瘤细胞在软琼脂上的集落能力。在分子机制研究中，我们发现ITPKA与MDM2相互作用，稳定了p53的蛋白水平。此外， miR-203在卵巢癌中抑制ITPKA的表达，过表达ITPKA解除miR-203对卵巢癌细胞克隆集落能力的促进作用。综上所述，本研究揭示了miR-203的下游基因ITPKA在卵巢癌发生发展中的重要作用，为卵巢癌的治疗提供了新的靶点。