第二型膜上絲胺酸蛋白酶II在攝護腺癌細胞扮演的角色

Role of TMPRSS2 in the progression of prostate cancer cells

黃正忠(Cheng-Chung Huang)

指導教授 ： 李明學

國立臺灣大學/醫學院/生物化學暨分子生物學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01479

摘要

攝護腺癌是西方男性最常發生的癌症之一。在台灣，因為生活飲食習慣逐漸地西化，攝護腺癌有逐年上升的趨勢，其死亡率在癌症死亡中排名第七位。目前對於人類攝護腺癌在轉變成為較惡化或具高度轉移的分子機制，尚未十分明瞭。近年來，有相關報告提出細胞表層蛋白分解反應的失調被認為與癌症的侵襲及轉移有直接的相關性。
因此，在本篇研究中，我們想探討可受雄性荷爾蒙調控的嵌膜絲胺酸蛋白酶:第二型膜上絲胺酸蛋白酶II (TMPRSS2)，在攝護腺癌細胞演進過程中所扮演的角色。首先我們將可表現此蛋白酶膜外區域的DNA片段建構在一個帶有組胺酸標記的哺乳動物分泌載體內，利用HEK293T細胞株進行蛋白表達並純化此蛋白做為抗原，以製作抗體。與林陳鏞博士合作下，我們成功地獲得一株可專一辨認第二型膜上絲胺酸蛋白酶II的單株抗體。在三株雄性荷爾蒙非依賴型細胞株 (DU145、PC-3 及 LNCaP C-81) 及一株雄性荷爾蒙依賴型細胞株LNCaP C-33中，第二型膜上絲胺酸蛋白酶II主要表現在荷爾蒙依賴型的細胞，其表現量會隨著細胞對雄性賀爾蒙非依賴的程度及高度侵襲能力的上升而下降。當使用核糖核酸干擾技術專一地將第二型膜上絲胺酸蛋白酶II的表現抑制時，會提升細胞生長的能力，但卻會使雄性荷爾蒙接收體以及攝護腺特異性抗原 (PSA) 的表現量減低。同時，我們也發現第二型膜上絲胺酸蛋白酶II對雄性荷爾蒙所調控的間質蛋白酶 (matriptase) 活化、攝護腺特異抗原的產生以及攝護腺癌細胞的生長，都扮演著重要的角色。另一方面，在攝護腺癌細胞演進的過程中，當第二型膜上絲胺酸蛋白酶II表現受到抑制時，會促使上皮細胞生長因子接受體表現上升，進而增強細胞對上皮細胞生長因子的敏感性，易於反應生長刺激。總歸上述，本篇研究結果顯示當減少或失去第二型膜上絲胺酸蛋白酶II的表現時，會促進細胞生長以及對上皮細胞生長因子的敏感度，進而在攝護腺癌細胞演進的過程中扮演一個重要的角色。

關鍵詞: 第二型膜上絲胺酸蛋白酶II；攝護腺癌；雄性荷爾蒙接受體；上皮細胞生長因子接受體；間質蛋白酶；前列腺蛋白酶。

關鍵字

第二型膜上絲胺酸蛋白酶II ； 攝護腺癌 ； 雄性荷爾蒙接受體 ； 上皮細胞生長因子接受體 ； 間質蛋白酶前列腺蛋白酶

並列摘要

Prostate cancer is one of the most common cancers among men in the western countries. In Taiwan, the incidence of prostate cancer has been rising to the seventh leading cause of cancer-related death, partly due to westernized life style and diets. Human prostate cancer usually undergoes several alterations to progress to advanced stages with androgen-independence and/or high metastasis. The molecular mechanisms for the progression are still not well understood. Recently, it has been proposed that deregulation of cell surface proteolysis is strongly involved in cancer cell invasion and metastasis.
In this study, we are interested in addressing the role of an androgen-regulated, membrane-anchored serine protease TMPRSS2 in the progression of prostate cancer cells, since a decreased expression of TMPRSS2 was shown in advanced prostate cancer. To explore the role of TMPRSS2 in prostate cancer, a monoclonal antibody (AL-20) against the protease was successfully generated by constructing the cDNA fragment encoding the extracellular region of TMPRSS2 inserted into a mammalian secretory vector with a His tag and purifying the fusion proteins as an antigen. With three androgen-independent prostate cancer cells (DU145, PC-3 and LNCaP C-81 cells) and an androgen-sensitive LNCaP C-33 cell, our data showed that the protein levels of TMPRSS2 were decreased in those cells with androgen-independence and highly invasive potentials. Moreover, a reduction of TMPRSS2 expression by shRNA approaches increased prostate cancer cell proliferation, but decreased the expression of androgen receptor (AR) and prostate-specific antigen (PSA). Furthermore, our data showed that TMPRSS2 was important for Dihydrotestosterone (DHT) -induced matriptase activation, PSA production and prostate cancer cell growth. On the other hand, down regulation of TMPRSS2 during the progression of prostate cancer cells decreased matriptase activation and increased the protein level of EGFR, leading to enhancement of EGF sensitivity for growth stimulation. Taken together, this study indicates that a decrease/loss of TMPRSS2 expression may play a role in the progression of prostate cancer cells, at least in part via increasing cell growth and EGF sensitivity.

Key words: TMPRSS2; prostate cancer; androgen receptor; EGFR; matriptase; prostasin.

並列關鍵字

TMPRSS2 ； prostate cancer ； androgen receptor ； EGFR ； matriptase ； prostasin

參考文獻

1. Jemal A, Siegel R, Ward E, Hao Y, Xu J, Thun MJ. Cancer statistics, 2009. CA Cancer J Clin 2009;59:225-49.

2. Cheung WL, Turner FB, Krishnamoorthy T, Wolner B, Ahn SH, Foley M, Dorsey JA, Peterson CL, Berger SL, Allis CD. Phosphorylation of histone H4 serine 1 during DNA damage requires casein kinase II in S. cerevisiae. Curr Biol 2005;15:656-60.

3. Agarwal DK, Costello AJ, Peters J, Sikaris K, Crowe H. Differential response of prostate specific antigen to testosterone surge after luteinizing hormone-releasing hormone analogue in prostate cancer and benign prostatic hyperplasia. BJU Int 2000;85:690-5.

4. Chen CD, Welsbie DS, Tran C, Baek SH, Chen R, Vessella R, Rosenfeld MG, Sawyers CL. Molecular determinants of resistance to antiandrogen therapy. Nat Med 2004;10:33-9.

5. Hsieh AC, Small EJ, Ryan CJ. Androgen-response elements in hormone-refractory prostate cancer: implications for treatment development. Lancet Oncol 2007;8:933-9.