基于氟维司群耐药细胞筛选ER特异相互作用蛋白谱探究雌激素受体阳性乳腺癌氟维司群耐药机制

Hormone receptor-positive breast cancer accounts for approximately 70% of all breast cancer subtypes, of which endocrine therapy has played an important role. However, endocrine resistance has seriously affected the treatment effect. Fulvestrant, as a new generation of selective estrogen receptor (ER) downregulation, still can not avoid the drug resistance problem even though it has an increasingly significant therapeutic status. Solving the dilemma of resistance to fulvestrant can bring new prospects for breast cancer endocrine therapy. Previous studies have demonstrated the dysfunction of coactivators’ recruitment of ER protein induced by fulvestrant which would result in an anti-estrogenic effect at the genomic level by inhibiting gene expression. It is speculated that the tumor cells would retain proliferation through combining specific protein to ER to resist the anti-tumor effect of fulvestrant. We plan to explore the mechanism of fulvestrant resistance from the level of protein by screening fulvestrant-resistant cell line specific ER interaction protein. And we will explore whether inhibiting specific ER binding protein of the resistant cell line could reverse the drug resistance and provide new clues for clinical transformation research.

激素受体阳性乳腺癌约占全部乳腺癌分型的70%，内分泌治疗在其治疗中占据重要地位，然而内分泌耐药严重影响了治疗效果。氟维司群作为新一代选择性雌激素受体（ER）下调剂发挥重要治疗作用，但仍然无法避免耐药问题，解决氟维司群耐药问题将为乳腺癌内分泌治疗带来新的前景。既往研究已发现氟维司群引起ERα蛋白招募共激活因子功能障碍从而抑制基因表达，从基因层面发挥抗雌激素作用。据此我们推测在发生氟维司群耐药后，肿瘤细胞ER可能通过结合特异蛋白促进细胞增殖抵抗氟维司群抗肿瘤作用。因此本研究立足于蛋白研究层面，通过筛选氟维司群耐药细胞株中特异ER相互作用蛋白探索其耐药机制，发掘ERα在结合氟维司群后是否有新的获得性功能，并初步探究改变耐药细胞株特异ER结合蛋白是否可逆转耐药，为临床转化研究提供新的线索。

氟维司群作为新一代选择性雌激素受体（ER）下调剂，在激素受体阳性乳腺癌病人治疗中发挥重要治疗作用，但仍然无法避免耐药问题，解决氟维司群耐药问题将为乳腺癌内分泌治疗带来新的前景。既往研究已发现氟维司群引起ERα蛋白招募共激活因子功能障碍从而抑制基因表达，从基因层面发挥抗雌激素作用。据此我们推测在发生氟维司群耐药后，肿瘤细胞ER可能通过结合特异蛋白促进细胞增殖抵抗氟维司群抗肿瘤作用。本研究通过建立氟维司群耐药细胞，再经由蛋白免疫沉淀并结合质谱鉴定技术，鉴定出雌激素受体ER新的结合蛋白：90KD热休克蛋白AB1（HSP90AB1）。通过外源性和内源性相互作用鉴定了两者的相互结合。我们还发现，氟维司群能促进雌激素受体ER与HSP90AB1蛋白的结合。而在野生型MCF-7细胞中，HSP90AB1表达较氟维司群耐药MCF-F细胞表达低。在MCF-7细胞过表达HSP90AB1基因后，我们发现MCF-7细胞显著增加了对氟维司群耐受。本研究发现了热休克蛋白HSP90AB1通过加强与雌激素受体结合，发挥乳腺癌细胞氟维司群耐药的作用，HSP90AB1抑制剂可能作为潜在的，解决乳腺癌细胞氟维司群耐药的新途径。