結論：
我們的結果指出ADAM9會與半橋粒的組成元件如BP180、Integrin β4與plectin相互作用，並已觀察到調控Integrin β4的內吞與降解。攝護腺癌細胞在抑制BP180的表現量後亦影響半橋粒構成進而影響整體細胞移行能力。
因此，我們將來可藉由阻斷ADAM9和BP180的相互作用或直接抑制BP180之表現以達到抑制攝護腺癌細胞的轉移趨勢。
Backgrounds:
Collagen XVII (BP180), a major component of the hemidesmosome is critical in the maintenance of cell adhesion. Clinical evidences indicated mutation or loss of BP180 leaded to subepidermal tissue separation. In addition, BP180 has been shown to play an important role of cancer migration and metastasis. However, the detail mechanism is still not clear. Hence, we aimed to investigate the mechanisms of BP1 80 in regulation of cancer migration and invasion.
Materials and Methods:
We first knockdown the expression levels of BP180 in PC3 cell lines. Lentiviral knockdown of BP180 was constructed. Real-time PCR was used to confirm knockdown efficiency. Cell adhesion, spreading and migration assay was performed. ADAM9 followed by analysis of BP180, expression was performed. Protein Integrin β4 degradation of hemidesmosome components after knockdown of ADAM9 was determined by cycloheximide treated prostate cancer cells.
Results:
We noticed the differential expression pattern of BP180 across different cell lines, with strong expression in prostate cancer cells and lowest in lung cancer carcinoma, especially in PC3 cell. Inhibition of cell migration activities can be detected in prostate cancer cell line, PC3 after knockdown of BP180 expression. In addition, we also observed decreased cell spreading, as well as haptotactic migration activities on matrices. Furthermore, we confirmed the interaction of ADAM9 and Integrin β4 and observed the endocytosis and degradation. Furthermore, shedding of BP180 by ADAM9 reversed had been observed. But MMP inhibitor treated resulted in BP180 expression decreased.
Conclusion:
Our results indicated ADAM9 regulated hemidesmosome endocytosis and degradation by direct interaction with BP180. And knockdown of BP180 inhibited cell migration and spreading activities by upholding constitutive expression levels of hemidesmosome complex in prostate cancer cells.
Therefore, it is plausible to hypothesize the therapeutic strategy by blocking ADAM9-BP180 interaction could inhibit cancer cell metastasis activities.
