HCE萃取物對癌細胞侵襲能力以及血管新生的影響

Abstract

在台灣癌症死亡率排名已三十多年蟬聯冠軍。其中，這十年來，攝護腺癌和胰腺癌死亡增加率，遠高於其他癌症。大多數癌症患者在確診為癌症初期，其治癒率很高，但一旦癌症發生局部浸潤或轉移，發展成晚期癌症時，患者的預後往往極差。其中，癌細胞的侵襲以及血管新生是促使腫瘤由良性轉變成惡性的兩大關鍵步驟，包含組織重塑以及促使腫瘤進展。雖然對於癌症治療的相關研究不斷在進行，直至今日仍尚未出現對轉移性癌症具效用的療法。針對轉移性癌症，化學治療是普遍常用的療法之一，但大多數化療藥物有嚴重的副作用，使患者疲勞、噁心、嘔吐以及造成身體虛弱。雖然已有標靶藥物的出現，大多只限於某些階段或特定類型的癌症。因此針對此癌症開發具療效且低毒性的新藥物，有迫切性的需要。天然植物萃取物一般具低毒性且草藥原料被使用於保健已有長期的經驗。因此從天然植物萃取物找出有效成份作為治療癌症的輔助療法或者替代療法，是一種潛力相對較高的方式。其中，HC已被廣泛應用在台灣和中國，用於抗病毒、抗菌、抗發炎及對抗癌症等方面。雖然HC已用於抑制癌症病程，但其有效成分尚不清楚。在本篇研究中，我想釐清HC萃取物是否具有療效成分能夠抑制人類腫瘤細胞的侵襲和血管生成，並且探討HCE抑制癌細胞侵襲力的作用機制。與中研院農生中心蕭培文老師及生物技術開發中心賴宗賢、錢瑤珍老師合作，HC酒精萃取物經高效能液相層析法分離出最有效的區分(命名為HCE)。結果顯示HCE能夠有效地抑制多種癌細胞的侵襲能力。這些癌細胞包括前列腺癌細胞(PC-3)以及胰腺癌細胞（Capan-1和PANC-1），有趣的是對低侵入性的MIAPaCa-2細胞的侵襲能力卻較不具影響力。在PC-3、PANC-1和Capan-1細胞中，發現HCE可經由調降第九型基質金屬蛋白酶九號(MMP9)和uPA的細胞表現量，降低其活性。同時HCE也透過降低FAK、Src的磷酸化，以及paxillin蛋白質的量，進而抑制癌細胞侵襲力。此外，HCE也可以減少HUVEC細胞的管狀構造形成以及雞胚絨毛尿囊血管的形成，顯示HCE也能夠抑制血管新生。總結以上的結果，HCE可以透過抑制FAK / Src的訊息傳遞以及MMP9、uPA的表達，進而有效地抑制癌細胞的侵襲能力。因此，HCE具有應用於腫瘤治療的相當潛力。

Cancer has been the leading cause of death in Taiwan for over thirty years. In the latest ten years, the mortality of both prostate and pancreatic cancers accelerates more rapidly than the other types of cancer in Taiwanese population. Most of the cancer patients diagnosed at early stages often have a well treatment with a high cure rate. However, once cancer progresses to an advanced stage with local invasion or metastasis, the prognosis of patients becomes poor. Two crucial steps that allow benign tumors to go malignant are cancer cell invasion and angiogenesis. Angiogenesis, sprouting of blood vessels from existing vasculature, is an important process involved in tissue remodeling and tumor progression. Although chemotherapy is often used to treat cancer, most of chemotherapeutic drugs have severe side effects and make the patients painful and weakening. Less toxic therapeutics are needed to improve the outcomes of cancer treatment. Although there are numerous target therapies available, they are all limited to use in certain stages or specific types of cancer. Therefore, to discover a new drug with low toxicity and high efficacy is imperative for cancer therapy. Herbal medicine has been evolved as preferred alternative treatments by patients with malignancies for many years, due to its low toxicity. Among them, HC has been wildly used in Taiwan and Eastern counties as a medicine for anti-virus, anti-bacteria, anti-cancer and anti-inflammation. In this study, I examined whether HC herbal extracts had effective ingredients to inhibit human cancer cell invasion and angiogenesis, as well as the underlying molecular mechanisms. Through collaborations with Drs. Pei-Wen Hsiao, Tzung-Hsein Lai and Yau-Jan Chyan, dry HC was extracted with ethanol and fractioned by HPLC. In cell invasion assays, the results showed that the most effective fraction, called HCE, could inhibit prostate cancer (PC-3) and pancreatic cancer (Capan-1 and PANC-1) cell invasion in a dose-response manner, however its effect on the poorly invasive MIAPaCa-2 cells was insignificant. Moreover, we identify that HCE was able to inhibit the expression levels of matrix metalloprotease-2, -3, -9, and uPA and decrease the phosphorylation levels of FAK, Src and paxillin. In addition, the effect of HCE on angiogenesis was further quested by the tube formation of HUVEC cells and CAM assays. The results suggest that HCE were able to suppress angiogenesis. In conclusion, the data indicate that HCE can effectually inhibit prostate and pancreatic cancer cell invasion, via down-regulation of pericellular proteolysis and FAK/Src signaling. The promising effects merit further study to identify the effective components of HCE and their therapeutic potentials.