TEMs调控上皮性卵巢癌lnc-CTSLP8-PKM2通路异常激活促进腹膜转移的机制研究

Most patients of epithelial ovarian cancer (EOC) is diagnosed at advanced stage with widely peritoneal metastasis and poor prognosis. Our early study has confirmed that the infiltration of Tie2+ monocytes/macrophages (TEMs) in EOC peritoneum was increased, and IGF1 derived from TEMs could directly increase the expression of lnc-RNA CTSLP8 (lnc-CTSLP8), and significantly promote EOC proliferation and peritoneal metastasis. Then RNA-pull-down combined with mass spectrometry detection confirmed that lnc-CTSLP8 could specifically combined to the M2-type pyruvate kinase (PKM2). By promoting the transformation of PKM2 to the tetrameric form, lnc-CTSLP8 significantly enhancing the aerobic glycolysis (Warburg effect) in EOC. Therefore, the applicant presumes that, TEMs could promote tumor metastasis by impacting metabolism after crosstalk with EOC. This study aims to elucidate the specific molecular mechanism of EOC metastasis promoted by TEMs through activating the lnc-CTSLP8-PKM2 pathway in EOC cells. Furthermore, we will clarify the specific binding sites between lnc-CTSLP8 and PKM2. And the relevant pathways blocking will be explored as an intervention. The expected results of the project will provide new targets for the diagnosis and treatment of EOC, and provide a theoretical basis for the study of the novel mechanism of molecular interaction between lncRNA and the key enzyme in tumor glucose metabolism pathway.

上皮性卵巢癌（EOC）确诊多为晚期，腹膜广泛转移，患者生存预后差。申请者前期研究证实，EOC腹膜内Tie2+单核巨噬细胞（TEMs）浸润增加，通过分泌IGF1上调EOC中长链非编码RNA（lnc-CTSLP8）表达，显著提高EOC增殖及转移能力；RNA-pull-down联合质谱证实，lnc-CTSLP8与M2型丙酮酸激酶（PKM2）特异性结合最强，促进PKM2形成四聚体，加强EOC有氧糖酵解（Warburg效应）。故提出科学问题，TEMs与EOC发生交叉对话，通过影响代谢通路促进肿瘤转移。本项目重点揭示腹膜微环境TEMs激活EOC中lnc-CTSLP8-PKM2通路，促进转移的分子机制，解析lnc-CTSLP8与PKM2具体结合位点，进一步探索相关通路分子阻断能否作为干预疾病进展的手段，期望建立EOC诊治新策略，并为阐明“lncRNA-肿瘤代谢关键酶”这一新的分子机理提供理论依据。

近70%的上皮性卵巢癌（EOC）患者在确诊时表现为腹膜表面的广泛转移种植。腹膜肿瘤微环境是个肿瘤细胞、免疫细胞和肿瘤相关基质细胞共同调控和作用的复杂网络，了解腹膜微环境中的细胞互作是探索EOC腹膜转移过程的关键。近年来研究表明，非编码RNA-lncRNA可以调控肿瘤细胞及微环境中相关基质细胞的基因表达，从而促进卵巢癌的转移进展。课题组前期研究发现，腹膜富集的Tie2+单核巨噬细胞能通过分泌IGF1分子从而使肿瘤细胞上调组织蛋白酶 L 假基因 8 （lnc-CTSLP8）的表达，最终促进卵巢癌的进展。通过对临床样本的原位杂交及组织化学染色分析，课题组成员发现，lnc-CTSLP8在EOC转移组织的表达显著高于原位灶，且与EOC患者的生存率呈负相关关系。我们进一步研究发现，增高EOC细胞内增高的lnc-CTSLP8能够增强肿瘤细胞的有氧糖酵解，上调肿瘤细胞促癌因子半胱氨酸组织蛋白酶 L（CTSL1）的表达，并提高肿瘤细胞的自噬水平，从而促进EOC细胞的增殖、侵袭转移及化疗耐药。此外，我们还发现lnc-CTSLP8能够通过与糖酵解途径的关键酶，即丙酮酸激酶M2（PKM2）结合，形成转录调控复合物，促进致癌基因c-MYC的表达。本研究证实了腹膜微环境能通过调控EOC细胞内的lnc-CTSLP8从而调控细胞侵袭转移、代谢及耐药，并阐明了其中的分子机制，为EOC提供了新的潜在治疗靶点和预后评估指标。