TMTC1透過integrins β1和β4促進卵巢癌細胞侵襲

Abstract

研究目的:卵巢癌是目前最致命的婦科惡性腫瘤。儘管O型甘露醣基轉移酶TMTC1在卵巢癌中有過度表現的情形，在卵巢癌中所扮演的角色仍然是未知的。 研究方法:透過免疫組織化學染色方法分析檢體中TMTC1的表現。經由卵巢癌細胞生長、移動、侵襲能力以及貼附的實驗，評估體外環境中的惡性特質。體內環境中的惡性特質則是藉由腹膜轉移測定。ConA的pull-down以及醣蛋白質體技術則是用於鑑定TMTC1的受體。 研究結果:與鄰近的正常卵巢組織相比，TMTC1在卵巢癌組織中有過度表現的狀況，且TMTC1過度表現與卵巢癌患者的不良預後明顯相關。降低TMTC1在卵巢癌細胞中的表現量，能夠抑制卵巢癌細胞的生長、移動、侵襲能力以及貼附。裸鼠的腹膜轉移測定中我們發現降低TMTC1的表現量，能夠抑制腹膜腫瘤的生長和轉移。另一方面，增加TMTC1在卵巢癌細胞中的表現量則是促進這些惡性特質。integrin β1以及β4是TMTC1的受體，TMTC1造成的移動與侵襲能力會被integrin β1或β4的siRNA阻斷。 研究結論: TMTC1主要是透過調控integrins β1和β4的O型甘露醣基化而促進卵巢癌的細胞侵襲且是具有潛力的卵巢癌症治療分子標靶。

Objective. Among gynecological malignancies, the most lethal tumor is ovarian cancer. Although O-mannosyltransferase transmembrane and tetratricopeptide repeat containing 1 (TMTC1) exhibits high expression levels in ovarian cancer, no studies have investigated its precise role in ovarian cancer. Methods. TMTC1 expression levels in clinical samples were examined by immunohistochemistry. Malignant properties of ovarian cancer cells were evaluated by MTT, transwell migration, Matrigel invasion, and adhesion assays in vitro and peritoneal xenograft assay in vivo. Protein substrates of TMTC1 were identified using Concanavalin A (ConA) pull-down assay and glycoproteomic analysis. Results. In ovarian cancer patients, the expression of TMTC1 was found to be higher in the cancerous tissue specimens compared to the corresponding adjacent normal tissues. The high expression level of TMTC1 was significantly correlated with a poor prognosis among patients diagnosed with ovarian cancer. Knockdown of TMTC1 inhibited ovarian cancer cell viability, migration, invasion, and cell-laminin adhesion in vitro, in addition to inhibiting peritoneal tumor growth and metastasis in vivo. Conversely, TMTC1 overexpression promoted these malignant properties. Through mass spectrometry, integrins β1 and β4 were identified as new protein substrates of TMTC1. Notably, knockdown of integrin β1 or β4 was sufficient to reverse the TMTC1-induced migration and invasion. Conclusions. TMTC1 facilitates the invasive behaviors of ovarian cancer cells mainly via integrins β1 and β4, making it a promising and potential target for therapeutic interventions in ovarian cancer.