肝素酶非酶活性增强TFEB介导的自噬途径促胃癌细胞增殖的作用及分子机制研究

Literature and previous studies have confirmed that heparanase (HPA) was closely associated with invasion and metastasis and proliferation of gastric cancer via enzymatic degradation of heparan sulfate proteoglycan (HSPG) in extracellular matrix (ECM) and releasing biological active factors. We also found that HPA can promote the proliferation of gastric cancer cells via its non-enzymatic activity, but the mechanism is unknown. Our previous preliminary experiments have demonstrated that HPA can promote autophagy by promoting autophagosome and lysosome formation, thereby enhancing the proliferation of gastric cancer cells, and the process does not depend on its enzymatic activity; Transcription factor EB (TFEB) is an important transcription factor that regulates autophagy-lysosomal signaling, HPA can be combined with TFEB under the guidance of its nuclear localization sequence (NLS) and enhance the transcriptional activity of TFEB, thus promoting autophagy. Therefore, we hypothesize that “HPA can be used as an auxiliary transcription factor to promote the autophagy-lysosomal signaling mediated by TFEB, thus enhancing the proliferation capacity of gastric cancer cells, and the process is independent of HPA enzymatic activity”. This project intends to further clarify the role and mechanism of HPA non-enzymatic activity in TFEB-mediated autophagy pathway and gastric cancer proliferation using molecular biology technology and animal experiments, which will provide a new strategy for the design of HPA non-enzymatic activity targeting drugs.

文献及课题组前期研究均证实肝素酶（Heparanase, HPA）可通过酶促作用破坏细胞外基质（ECM）,并释放HSPG侧链锚定的生物活性因子，促进胃癌细胞侵袭、转移及增殖。我们前期研究还发现HPA非酶活性亦可促进胃癌细胞增殖，但其机制不明。预实验发现HPA可通过促进自噬小体和溶酶体生成增强自噬，进而促进胃癌细胞增殖能力，此过程可不依赖其酶活性；TFEB作为调控自噬-溶酶体信号重要的转录因子，HPA可在其核定位序列（NLS）引导下在核内与TFEB结合，并增强TFEB的转录活性，进而促进细胞自噬。据此我们提出“HPA可作为辅助转录分子促进TFEB介导的自噬-溶酶体信号，从而增强胃癌细胞增殖能力，并且此过程可不依赖其酶促活性”的假说。本课题拟采用分子生物学技术及动物实验，阐明HPA非酶活性在TFEB介导的自噬途径及胃癌增殖中的作用及其机制，旨在为HPA非酶活性靶向药物的研发提供新的理论依据。

文献及课题组前期研究均证实肝素酶（Heparanase, HPA）可通过酶促作用破坏细胞外基质（ECM）,并释放HSPG侧链锚定的生物活性因子，促进胃癌细胞侵袭、转移及增殖。我们前期研究还发现HPA非酶活性亦可促进胃癌细胞增殖，但其机制不明。预实验发现HPA可通过促进自噬小体和溶酶体生成增强自噬，进而促进胃癌细胞增殖能力，此过程可不依赖其酶活性；TFEB作为调控自噬-溶酶体信号重要的转录因子，HPA可在其核定位序列（NLS）引导下在核内与TFEB结合，并增强TFEB的转录活性，进而促进细胞自噬。据此我们提出“HPA可作为辅助转录分子促进TFEB介导的自噬-溶酶体信号，从而增强胃癌细胞增殖能力，并且此过程可不依赖其酶促活性”的假说。本课题拟采用分子生物学技术及动物实验，阐明HPA非酶活性在TFEB介导的自噬途径及胃癌增殖中的作用及其机制，旨在为HPA非酶活性靶向药物的研发提供新的理论依据。