2型丙酮酸激酶调控胰腺癌肿瘤相关巨噬细胞亚型转变的分子机制

The relationship between Pyruvate kinase -2 and carcinogenesis as well as pancreatic cancer progression is intimate but poorly defined. Meanwhile, tumor-associated macrophages (TAM) increase significantly in pancreatic cancer. TAMs often express an M2-like phenotype, promoting tumor growth through secreted immunosuppressive factors. Our group found that pancreatic cancer has high expression of Pyruvate kinase -2, which modulates TAM subtype transition in pancreatic cancer microenvironment, and further promote pancreatic carcinogenesis and progression. In this project, we will focus on whether Pyruvate kinase -2 can regulate TAM subtype transition or not and further investigate the molecular mechanism underway. The following projects will be studied in this proposal: 1) To observe the expression of Pyruvate kinase -2 and TAM in pancreatic cancer; 2) To explore the mechanism that Pyruvate kinase -2 regulates TAM subtype transition in pancreatic cancer; 3) To investigate the effect of Pyruvate kinase -2 through regulating TAM subtype transition in animal model; 4) Interference of critical pathways involved in the induction of macrophage M2 polarization by Pyruvate kinase -2 to investigate how they affect the tumor growth and tumor microenvironment. This research will be significant for learning of Pyruvate kinase -2 in the carcinogenesis and cancer progression of pancreatic cancer.

2型丙酮酸激酶与胰腺癌发生发展密切相关，但其具体生物学机制尚不清楚。胰腺癌组织中存在大量的肿瘤相关巨噬细胞，多为M2型，通过分泌免疫抑制因子等途径促进肿瘤生长。我们的前期研究观察到：肿瘤细胞2型丙酮酸激酶表达增加，后者可能促使胰腺癌肿瘤微环境的肿瘤相关巨噬细胞发生M2亚型转变，进而促进肿瘤的发生发展。本研究拟从四个方面研究2型丙酮酸激酶诱导胰腺癌肿瘤相关巨噬细胞亚型转变及其分子机理:1) 明确胰腺癌2型丙酮酸激酶与肿瘤相关巨噬细胞的表达；2) 2型丙酮酸激酶促进肿瘤相关巨噬细胞极化的分子机制研究；3) 动物模型验证2型丙酮酸激酶促进肿瘤相关巨噬细胞极化的分子机理；4）阻断2型丙酮酸激酶诱导肿瘤相关巨噬细胞M2型极化的相关通路对肿瘤生长及其微环境的影响。本课题的研究对于更好地认识2型丙酮酸激酶与肿瘤发生发展的关系及探讨其临床应对策略具有重要的意义。

胰腺癌组织中存在大量M2型肿瘤相关巨噬细胞(Tumor-associated macrophage，TAM)，通过分泌免疫抑制因子等途径促进肿瘤生长。2型丙酮酸激酶(Pyruvate kinase -2，PKM2)与胰腺癌发生发展密切相关，但其具体生物学机制尚不明确。我们的前期研究观察到：构建sh RNA干扰PKM2表达的胰腺癌细胞，其肿瘤微环境的M2水平明显下降。提示PKM2可能促进TAM由M1向M2亚型转化。流式检测发现抑制PKM2入核后，M2巨噬细胞极化比例下调，说明PKM2入核能够促进M2巨噬细胞极化。通过进一步的分子生物学实验，我们的研究还显示：胰腺癌肿瘤微环境的M2型肿瘤相关巨噬细胞促进肿瘤细胞2型丙酮酸激酶由四聚体转化为二聚体入核，引起肿瘤细胞PD-L1转录增加,高表达的PD-L1与NK细胞膜上的PD-1结合，抑制后者活化及杀伤功能，促进肿瘤发生发展。本研究深入探索了2型丙酮酸激酶促进肿瘤相关巨噬细胞M2极化，以及M2型肿瘤相关巨噬细胞调控2型丙酮酸激酶并进一步影响肿瘤细胞PD-L1表达，而后影响NK细胞活化及杀伤功能。深入理解肿瘤相关巨噬细胞调控2型丙酮酸激酶入核而后进一步调控NK细胞功能的分子机制，对于更好地认识肿瘤相关巨噬细胞与肿瘤发生发展的关系及探讨其临床应对策略具有重要意义。