LXR 致效劑對於男性賀爾蒙非依賴型人類前列腺癌細胞 PC- 3 和 DU- 145的遷移、侵入及散佈抑制作用之探討

Effect of LXR Agonist on Migration, Invasion, and Progression of Androgen-Independent PC3 and DU-145 Human Prostate Cancer Cells

洪于雯(Hung, Yuwen)

指導教授 ： 楊孝德 ； 褚志斌

國立清華大學/生命科學院/分子與細胞生物研究所/碩士(2014年)

摘要

根據美國癌症協會2013年的估計，前列腺癌(prostate cancer)是男性最常罹患的癌症，每7人就會有一位被診斷出患有前列腺癌；且前列腺癌在美國男性癌症死亡排名第二。亞洲國家男性罹患前列腺癌的比率比西方國家低很多，但在台灣也是男性十大癌症之一（7. 3 %；台灣登記中心）。由此可知，前列腺癌治療的相關研究是有其重要且必要性的。
前列腺癌的治療方式是由芝加哥大學的查理哈更斯(Charles Huggins)教授在1941年提出。哈更斯發現前列腺癌細胞的生長需要倚賴男性荷爾蒙(androgen)，稱為男性荷爾蒙依賴型前列腺癌 (androgen- dependent prostate cancer)。他證明以手術去勢抑制病患體內男性荷爾蒙，可以讓前列腺腫瘤萎縮而治癒；目前臨床上醫生使用促性腺釋放激素(luteinizing hormone-releasing hormone，LHRH) 類似物(analogue) 抑制病患體內的男性荷爾蒙。然而，80-90%的前列腺癌病患經過男性荷爾蒙抑制治療2- 3年後，消失的腫瘤會再度復發(relapse)；復發的腫瘤不再倚賴男性荷爾蒙，成為非男性荷爾蒙依賴型前列腺癌(androgen- independent prostate cancer)。攝護腺癌症復發後病人約可再存活2- 3年，這種復發的癌症至今仍沒有有效的治療方式。
LXR (liver X receptor) 調節著體內膽固醇、脂肪酸以及葡萄糖的恆定，而人工合成的T0901317 LXR致效劑對於促進LXR活性有很好的效果。最近的研究顯示T0901317可以有效地降低前列腺癌細胞PC- 3 和DU145 的增生及細胞週期的發展；本實驗利用LXR致效劑 T0901317 (LXR agonist) 對非男性荷爾蒙依賴型前列腺癌細胞PC- 3及DU145進行處理，從細胞遷移(migration)、侵入(invasion) 等細胞實驗及利用體內成像系統(in vivo imaging system)判斷並推論LXR致效劑 T0901317 是否能有效的抑制前列腺癌細胞的轉移(metastasis)。經過T0901317 96小時投藥過後，PC- 3與DU145前列腺癌細胞的遷移（migration）和侵入（invasion）能力有大幅的下降；除此之外，相同的結果也在動物實驗中得到應証，經過10 週T0901317餵食（gavage）之裸鼠其體內PC- 3轉移訊號相較於未治療組小鼠明顯降低。此外，進一步的利用高通量西方點墨微陣列(Micro-Western Array)及免疫組織染色(immunohistochemistry) 確定細胞內與轉移相關之蛋白質變化量；我們發現T0901317的作用會降低與細胞增生以及 EMT(epithelial- to -mesenchymal transition) 相關蛋白質的活性，像是Akt、NFκB、 c-Myc和snail。從細胞及動物實驗中的結果顯示出T0901317其有效的轉移抑制能力；未來將會進一步的分析癌症指標中與癌症轉移（metastasis）相關的因子，以期得到T0901317作用機制，並提供進一步開發腫瘤藥物的重要資訊。

關鍵字

LXR致效劑 ； 前列腺癌 ； 轉移

並列摘要

Prostate cancer (PCa) is the second most frequently diagnosed cancer of men and the fifth most common cancer overall in the world. Surgeries, such as radical prostatectomy or transurethral resection of the prostate (TURP), are often successful for organ-confined prostate cancer. However, approximately 15% to 30% of patients with localized disease receiving surgery develop relapsed tumors within 5 to 10 years. Most of these patients subsequently show poor therapeutic outcome. More than 80% of patients died from PCa developed bone metastases. Liver X receptors (LXRs) belong to the nuclear receptor superfamily and LXR regulates the homeostasis of cholesterol, fatty acids and glucose. We previously reported that LXR agonist treatment suppresses proliferation of PCa cells via induction of G1 cell cycle arrest. In this study, we demonstrated that LXR agonist T0901317 treatment suppressed migration and invasion of PC-3 and DU-145 human prostate cancer cells. Metastasis of PC-3 xenografts in nude mice was reduced by oral administration of T0901317. Micro-Western Array (MWA) is an antibody-based modified reverse phase array composes of a GeSim Nanoplotter arrayer, a GE multiphor, and a Licor Odyssey scanner. Micro-Western Array allows detecting protein expression level or phosphorylation status change of 96-384 different antibodies in 6-15 samples simultaneously. Micro-Western Array study and immunohistochemistry (IHC) staining indicated that T0901317 treatment reduced signaling proteins involved in regulation of cell proliferation and epithelial-to-mesenchymal transition (EMT), including Akt, NFκB, c-Myc, and snail. Our observations suggested that LXR agonists may be a potential candidate for prevention and inhibition of prostate cancer metastasis.

並列關鍵字

Liver X receptor ； Prostate cancer ； EMT

參考文獻

1. Huggins, C. and C.V. Hodges, Studies on prostatic cancer. The Journal of Urology. 167(2): p. 948-951.

2. Debes, J.D. and D.J. Tindall, Mechanisms of androgen-refractory prostate cancer. N Engl J Med, 2004. 351(15): p. 1488-90.

3. Petrylak, D.P., et al., Docetaxel and estramustine compared with mitoxantrone and prednisone for advanced refractory prostate cancer. N Engl J Med, 2004. 351(15): p. 1513-20.

4. Chuu, C.P., et al., Inhibition of tumor growth and progression of LNCaP prostate cancer cells in athymic mice by androgen and liver X receptor agonist. Cancer Res, 2006. 66(13): p. 6482-6.

5. Zelcer, N. and P. Tontonoz, Liver X receptors as integrators of metabolic and inflammatory signaling. J Clin Invest, 2006. 116(3): p. 607-14.