Matriptase表达上调在慢性淋巴细胞白血病中的作用机制及治疗靶点价值研究

Matriptase, also called membrane-type serine protease 1 or epithin, is a member of the type II transmembrane serine protease family. Studies have indicated that matriptase plays an important role in epithelium-derived solid tumors. To date, however, little is known about the biological function of matriptase in blood. In our preliminary studies, we found that matriptase mRNA and protein were highly up-regulated in bone marrow cells from patients with chronic lymphocytic leukemia (CLL). The expression appeared to be specific because high matriptase mRNA and protein expression was not detected in peripheral blood cells from normal individuals or from patients with acute lymphocytic leukemia (ALL) or acute/chronic myelocytic leukemia (AML/CML). By confocal immunofluorescent microscopy, we found that matriptase was expressed on the CLL cell surface. Most importantly, we showed that silencing the matriptase gene in B-cell-derived lymphoma cells markedly inhibited the cancer cells in invading Matrigels. These data indicate that matriptase may play an important role in the pathogenesis of CLL. In this proposed study, we plan to conduct in vitro and in vivo experiments to study the mechanisms underlying matriptase expression and function in CLL. Our results may help to determine if matriptase could be used as a biomarker or therapeutic target in the diagnosis and treatment of CLL.

Matriptase是一种II型跨膜丝氨酸蛋白酶。大量研究已证实该酶与多种实体肿瘤密切相关，但迄今它在血液中的生物学功能尚未报道。我们的前期研究结果显示matriptase在慢性淋巴细胞白血病（CLL）患者骨髓细胞中表达明显增高，而在正常人或急性淋巴细胞白血病（ALL）和急/慢性粒细胞白血病（AML/CML）患者的骨髓细胞中基本不表达。免疫荧光实验证实matriptase定位于细胞膜表面；RNAi沉默matriptase的表达能够明显抑制肿瘤细胞的侵袭能力，从而提示matriptase在CLL发生发展过程中起到重要作用。本研究将通过检测matriptase在CLL中的异常表达，采用分子生物学和细胞生物学技术，从体内外角度探讨matriptase在CLL病程进展中所发挥的生物学功能及其作用机制。研究结果将为CLL疾病特点及机制研究提供基础依据，并可能为CLL提供新的诊的诊断指标及治疗靶点。

Matriptase作为一种II型跨膜丝氨酸蛋白酶，在正常生理条件及肿瘤中起着广泛而重要的作用，但是它在血液中的生物学功能尚无相关研究。通过本项目的研究，我们发现matriptase在慢性淋巴白细胞白血病（CLL）患者的骨髓细胞中特异性表达明显增高。免疫荧光实验证实matriptase定位于细胞膜表面；RNAi沉默matriptase的表达后，能够明显抑制肿瘤细胞的侵袭能力。RNAi沉默matriptase的表达或者抑制剂抑制matriptase的活性后，对细胞增殖影响不明显。通过对其内在的分子机制进行研究，发现matriptase在B细胞来源的淋巴瘤细胞系Namalwa高表达，其分子机制不同于以往研究的pro-HGF/c-Met通路，在沉默matriptase表达后，Namalwa细胞表面的PAR mRNA水平明显增高，意味着在Namalwa这个细胞系中，matriptase可能是通过另外的方式发挥其生理功能。此外，通过Annexin V/7-AAD标记实验，发现，matriptase表达被抑制后，Namalwa细胞的早期凋亡也明显受到抑制。体内研究也发现，matriptase表达被沉默后，裸鼠皮下肿瘤细胞的生长明显得到抑制。综上，我们的研究提示，matriptase参与了B淋巴细胞疾病的发生发展过程，研究结果将为CLL疾病特点及机制研究提供基础依据，并为CLL提供新的诊断指标及治疗靶点。