咖啡酸苯乙酯 (caffeic acid phenethyl ester, CAPE)是一種從蜂膠中萃取出的生物活性成分。本實驗室先前研究指出，不論是細胞實驗或是動物實驗，CAPE處理均能抑制男性賀爾蒙依賴型LNCaP 104-S 前列腺癌細胞生長。其分子機轉是透過抑制Akt與c-Myc的訊息傳遞路徑，因而導致細胞週期停滯在G1階段。目前轉移性前列腺癌最主要的治療方法是賀爾蒙療法 (Androgen ablation therapy)，但是大多數接受賀爾蒙療法的前列腺癌患者一至三年後，最終進展復發成非賀爾蒙依賴型前列腺癌 (CRPC)，復發後患者平均存活時間約一至兩年。目前仍然缺乏有效的治療方法，所以極需發展出新的治療方法。
LNCaP癌細胞株是從轉移到淋巴結的人類前列腺癌細胞中所產生。將男性賀爾蒙依賴型LNAaP 104-S癌細胞持續培養在缺乏男性賀爾蒙的環境下，能獲得非男性賀爾蒙依賴型的 LNCaP 104-R1 癌細胞株， LNCaP 104-R1癌細胞能模擬非賀爾蒙依賴型前列腺病患的情況。
我們發現CAPE處理能使LNCaP 104-R1癌細胞的細胞週期停滯在G1階段，進而抑制癌細胞增生，並能抑制裸鼠腫瘤生長。Micro-Western Array (MWA) 是種高通量西方點墨微陣列，能夠同時檢測6~15種樣品的96~384支抗體表現。藉由高通量西方點墨微陣列，我們發現CAPE處理在LNCaP 104-R1癌細胞中只是輕微抑制Akt訊息傳遞，卻能顯著抑制Skp2表現量。這也許可以解釋為何LNCaP 104-R1癌細胞相較於LNAaP 104-S癌細胞對於CAPE具有較大的耐受能力。Skp2過量表現能夠阻斷CAPE的抑制效果。CAPE與PI3K抑制劑-LY294002及B-cl2抑制劑ABT-737共同處理下都具有加乘效果。我們的發現指出CAPE具有潛力能做為非賀爾蒙依賴型前列腺癌的輔助治療。

Caffeic acid phenethyl ester (CAPE) is a bioactive component derived from honeybee hive propolis. We previously showed that treatment with CAPE suppresses growth of androgen-dependent AR-positive LNCaP 104-S cells both in vitro and in vivo via inhibition of Akt and c-Myc signaling, thus causes G1 cell cycle arrest. Androgen ablation therapy is the primary treatment for metastatic prostate cancer (PCa). However, a majority of PCa patients receiving the androgen ablation therapy will ultimately develop recurrent castration-resistant prostate cancer (CRPC) within 1-3 years after treatment with a median overall survival time of 1-2 years after relapse. There is currently no effective therapy and new therapeutic targets are needed. The LNCaP cancer cell line was established from a human lymph node metastatic lesion of prostatic adenocarcinoma. We have established AR-rich androgen-independent LNCaP 104-R1 cells derived from parental androgen-dependent LNCaP 104-S cells under androgen depleted condition. LNCaP 104-R1 cells mimic CRPC in patients. CAPE treatment caused G1 cell cycle arrest in 104-R1 cells and thus suppressed cell proliferation and tumor growth in nude mice. Micro-Western Array (MWA) is an antibody-based modified reverse phase array, which allows detecting protein expression level or phosphorylation status change of 96-384 different antibodies in 6-15 samples simultaneously. Using MWA platform, we found that CAPE reduced Akt-related proteins expression slightly, but decrease Skp2 abundance significantly, which may explain its larger resistance to CAPE treatment than 104-S cells. Overexpression of Skp2 blocked suppressive effect of CAPE. Co-treatment of CAPE with PI3K inhibitor LY294002 or Bcl-2 inhibitor ABT-737 both showed synergistic suppressive effects. Our finding suggested that CAPE treatment is a potential therapy for CRPC.

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