第二型轉麩胺酶促進肺癌細胞的移行及侵入

Transglutaminase 2 Promotes Cell Migration and Invasion in Lung Cancer Cells

黃晟協(Cheng-Hsieh Huang)

指導教授 ： 李宜儒 ； 許國堂

中山醫學大學/醫學院/醫學分子毒理學研究所/碩士(2008年)

摘要

第二型轉麩胺酶（transglutaminase 2，TG2）催化蛋白質的cross-linking、G蛋白的活性以及雙硫鍵異構酶的活性。此外，TG2可與integrin 及fibronectin 作用進而幫助細胞的黏附。近年來發現，TG2也影響癌細胞的抗藥性以及轉移。在此，我們使用低轉移性的肺癌細胞株CL1-0及高轉移性的CL1-5檢測TG2在肺癌轉移上所扮演的角色。我們的結果顯示，CL1-5的TG2的表現量高於CL1-0，而在CL1-0大量表現TG2能增加CL1-0細胞的移行及侵入，但不影響MMP-2及MMP-9的活性。然而TG2的轉麩胺酶活性非癌細胞轉移所必需，因為在CL1-0大量表現缺乏轉麩胺酶的TG2亦可提高細胞的移行及侵入，且在CL1-5或CL1-0/TG2加入TG2抑制劑monodansylcadaverine及cystamine並不會影響其能力。另外，CL1-5在conditioned medium中的TG2含量也高於CL1-0，若以CL1-5的conditioned medium或重組TG2蛋白加入CL1-0，可提高CL1-0的移行，但對CL1-0的侵入能力則因Boyden Chamber中覆蓋Matrigel的劑量而異。劑量低時，重組TG2可增加CL1-0侵入能力；劑量高時，則無法達成。為了進一步證明TG2的角色，我們利用antisense RNA以及RNA interference的技術降低CL1-5的TG2表現量，並發現CL1-5的轉移能力也隨之下降。由此得知，TG2在細胞移行及侵入方面扮演一正向之角色，可能因此而得以促進肺癌細胞的轉移。

關鍵字

第二型轉麩胺酶移行 ； 侵入

並列摘要

Transglutamianse 2 (TG2) catalyzes protein cross-linking and possesses activity of G-protein, kinase and protein disulphide isomerase. Moreover, TG2 has been shown to associate with integrin, thereby facilitating cell adhesion to fibronectin. Recent findings further reveal that TG2 plays roles in drug resistance and tumor metastasis. Here we investigate the involvement of TG2 in metastasis of lung cancer cells. Our results show that the highly invasive lung cancer cells CL1-5 exhibit higher levels of TG2 expression and transglutaminase activity than CL1-0, a lung cancer cell line displaying low potency of invasion. Over-expression of TG2 in CL1-0 enhances cell migration and invasion to a level comparable to CL1-5, but exerts no effect on morphology, cell growth and the secretion of matrix metalloproteinase 2 and matrix metalloproteinase 9. Over-expression of an inactive transglutaminase mutant TG2(C277S) in CL1-0 also augments cell migration and invasion, suggesting that TG activity is not required for promoting these cellular behavior. This notion is further supported by other observation that application of TG inhibitor, monodansylcadaverine and cystamine, into CL1-5 does not affect cell migration and invasion. Examination of the amount of TG2 in conditioned medium reveals that CL1-5 has more extracelluar TG2 than CL1-0. Furthermore, exogenous addition of the conditioned medium of CL1-5 or recombinant human TG2 increases the extent of cell migration in CL1-0, but their effect on invasion varies upon the amount of Matrigel coated on the membrane of the Boyden chamber. The amount of Matrigel is lower; the extent of cell invasion is higher in response to conditioned medium and recombinant TG2. By contrast, no obvious effect was observed when the amount of Matrigel is higher. To further confirm the role of TG2 in cell migration and invasion, expression of TG2 in CL1-5 is reduced by RNA interference and antisense RNA technique, and this leads to a decrease in cell migration and invasion. Thus, TG2 plays a positive role in cell migration and invasion, and this might confer the metastatic capacity of lung cancer cells.

並列關鍵字

TG2 ； migration ； invasion

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