缺氧微环境中衰老细胞上调SerpinB3表达促进黑色素瘤细胞生存的作用和机制研究

转移是影响黑色素瘤预后的重要因素，肿瘤细胞在转移部位的生存能力是转移形成的基础。丝氨酸蛋白酶抑制剂SerpinB3（SB3）能抑制溶酶体内参与细胞凋亡和抗原加工的半胱氨酸蛋白酶（Cath）活性，但SB3在细胞适应性生存中的作用机制不明确。申请人前期研究发现转移性黑色素瘤SB3高表达的患者生存率低，缺氧诱导的衰老细胞促进邻近细胞SB3表达及耐药性增加。在此基础上，我们拟以SB3对Cath活性的抑制作用为切入点，研究SB3的表达调控及其对细胞生存的影响。通过构建体内外缺氧-细胞衰老微环境，阐明衰老相关分泌因子IL-6通过Ras-MAPK和JAK-STAT3信号转导途径调控SB3表达的分子机制；观察SB3表达对细胞溶酶体功能及生存的影响；揭示SB3抑制线粒体途径凋亡及抗原加工的作用底物和机制。研究黑色素瘤微环境中SB3参与适应性生存的作用机制预期将为转移性黑色素瘤的治疗及药物研发提供新策略。

Metastasis is the most important factor affecting the prognosis of melanoma. Adaptation to the dynamic microenvironment is important for the survival of melanoma cells. Serine protease inhibitor, SerpinB3 (SB3) inhibits activity of cathepsin/cysteine protease (Cath), which is involved in cell apoptosis and antigen processing. However, mechanism of the adaptive regulation by SB3 remains unclear. Analysis of TCGA melanoma dataset showed that in metastatic melanoma group, the overall survival of patients with high SB3 expression was poor. In vitro studies showed that levels of SB3 and ability of drug-resistance were increased when co-cultured with hypoxia-induced senescent cells. Based on the inhibition of Cath activity by SB3, we propose to study the regulation of SB3 expression and its effects on melanoma cell survival via the model of hypoxia-induced senescence microenvironment. We aim to (1) elucidate molecular mechanism of up-regulation of SB3 by senescence-associated secretory factor IL-6 through Ras-MAPK and JAK-STAT3 signaling transduction pathways; (2) determine the effect of SB3 expression on lysosome function and melanoma survival; (3) explore the substrate and mechanism, by which SB3 inhibits apoptosis and attenuates immune recognition. In summary, the research of SB3-mediated adaptive survival of melanoma cells in dynamic microenvironment may contribute to novel strategy and drug development in metastatic melanoma.