| Abstract: | 臟癌 (Renal Cell Carcinoma, RCC)在世界排行為第七大癌症，其癌細胞轉移為最大的死亡原因之一。由於腎臟癌初期並無明顯病徵，因此大多病患發現時，癌細胞大多已轉移，目前最主要的治療方式為外科手術切除腫瘤合併使用化學療法，但仍存在預後不佳以及產生不良副作用，因此尋找轉移標靶分子及標靶治療是刻不容緩的課題。MTA2為MTA家族成員之一，主要參與NuRD (nucleosome remodeling and histone deacetylation) 複合體的調控機轉，目前已知MTA2調控許多癌細胞的生長及轉移，包括：乳癌、大腸直腸癌、胃癌、非小細胞肺癌以及肝癌等等，但MTA2在腎臟癌細胞中的角色，至今仍不清楚。因此本研究目的是釐清MTA2在腎臟癌細胞中所扮演的角色。 首先，本研究利用免疫組織化學染色法 ( Immunohistochemistry stain)證明人類腎臟癌組織中的MTA2蛋白表現量比正常腎組織高，並且利用西方墨點法以及Reverse Transcriptase Polymerase Chain Reaction發現腎臟癌細胞株A498、786-O、Achn以及Caki-1中的MTA2 蛋白質和mRNA表現量皆比正常腎小管HK2細胞株還高。為了進一步證實MTA2在腎臟癌細胞的生物功能，我們利用shRNA慢病毒系統載體抑制786-O內生性MTA2的表現。利用細胞生長速率實驗、流式細胞儀和西方墨點法證實抑制MTA2不影響人類腎臟癌786-O細胞的生長和細胞週期相關蛋白的表現。此外，細胞移動和侵襲實驗證實抑制MTA2後會抑制786-O細胞移動和侵襲能力，同時也會抑制MMP-1以及MMP-9蛋白表現，但不影響MMP-2蛋白表現。進一步分析MAPK相關蛋白 (ERK, JNK以及p38)和Akt途徑證實抑制MTA2會抑制ERK磷酸化，但不影響JNK及p38磷酸化。 綜合以上實驗結果，顯示MTA2在人類腎臟癌的轉移中扮演重要的調控角色，但是其相關分子作用機制仍需更進一步的實驗來證明。希望MTA2在人類腎臟癌轉移相關基因的治療上可以成為新穎靶基因的角色，對臨床上可以有更重要的應用。
MTA2 is a critical composition of the Mi2/Nucleosome remodeling and histone deacetylase (NuRD) complex, which contributed to the epigenetic silencing genes. More and more studies demonstrated MTA2 was associated with tumor cells proliferation, migration and invasion. In the previous studies it is shown MTA2 highly expressed in several tumors, including hepatocellular carcinoma, gastric cancer, glioma and breast cancer. However, the role of MTA2 of renal cell carcinoma is still unclear. Therefore, the aim of the study was to clear the biological function of MTA2 in renal cell carcinoma cells. At first, the renal carcinoma tissue array by immunohistochemistry staining suggest the MTA2 levels were positively associated with tumor grade, The MTA2 protein in four renal carcinoma cells (A498, 786-O, Achn and Caki-1) were higher expressed than in normal renal tubular HK2 cells. Following, the 786-O cells transfected by MTA2 shRNA was used for biological function investigation. MTT assay and Propidium iodide staining assay indicated knockdown of MTA2 had no effect on cells growth rate and cell cycle distribution, but inhibited the migration and invasion capacity of 786-O cells. In addition, knockdown of MTA2 in 786-O cells inhibited the protein expression of MMP-1 and MMP-9, but not MMP-2 protein. Moreover, knockdown of MTA2 might down-regulate ERK phosphoylation to inhibit cells migration and invasion. Based on the above evidence, MTA2 is important for renal cell carcinoma migration and invasion, and provides a potential target for clinical cancer metastasis research, and may open interesting perspectives to the strategy for human renal cell carcinoma therapy. |
