| 摘要: | 傳統中草藥中的七葉一枝花 (Paris polyphylla) 及北蟲草 (Cordyceps militaris) 均被認為具有抑制癌細胞增生及誘導凋亡的能力，但對癌細胞衍生的抗藥性及對癌幹細胞特性之影響仍缺乏相關機制探討。蟲草素 (3’-deoxyadenosine) 是一個可分離自北蟲草且具有抗癌活性的分子，已被知道可展現抑制血管新生、抑制轉移、抑制細胞增生的能力，並能誘導癌細胞凋亡。然而，蟲草素處理卵巢癌細胞對轉移/侵襲與粒線體活性的相關性仍不清楚。本研究進一步評估七葉一枝花的水萃取物 (aqueous extract of Paris polyphylla; AEPP) 及蟲草素對於人類卵巢癌細胞發生上皮-間質轉換 (epithelial-mesenchymal transition; EMT) 及粒線體活性的抑制能力；粒線體型態 (活性) 以 MitoTracker Deep Red FM 進行染色評估。
本研究結果發現蟲草素在對卵巢癌細胞不會發生細胞毒性的濃度下 (50及100 μM) 具有抑制 mitochondrial fusion 並促進 mitochondrial fission 的能力。此外，在經過 24 小時處理後，蟲草素可透過抑制 estrogen-related receptor (ERR)-alpha避免卵巢癌細胞發生 EMT 的情況。本研究第一次確認蟲草素處理可藉由調控粒線體活性來抑制卵巢癌細胞發生轉移，顯示蟲草素具有開發做為治療卵巢癌並抑制癌細胞轉移的藥物。最後，本研究探討蟲草素對於卵巢癌幹細胞之影響，Transforming growth factor-beta (TGF-beta) 則被用來處理 SKOV-3 卵巢癌細胞以誘導對 cisplatin 化療藥物發生治療抗性。結果顯示，SKOV-3 細胞存活率、癌幹細胞數量、matrix metalloproteinases (MMPs) 的表現量會因為 TGF-beta 誘導而增加，而蟲草素則對這些情況具有抑制能力。此外，TGF-beta 誘導則會影響與 EMT 有關的分子之蛋白質表現，包括抑制 E-cadherin 及增加 vimentin、peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1alpha) 表現量，而蟲草素的處理則能透過恢復 E-cadherin 及抑制 vimentin、PGC-1alpha 的表現量以調節 EMT 並抑制 SKOV-3 卵巢癌幹細胞的特性；此外，本研究也發現蟲草素可減弱因為 TGF-beta 處理 SKOV-3 卵巢癌幹細胞而誘導出對 cisplatin 衍生的化療抗性。另外，本研究也發現 AEPP 可降低 OVCAR-3 卵巢癌細胞的存活率並誘導凋亡。然而 AEPP 對 OVCAR-3 卵巢癌細胞的抑制能力會因為高糖誘導而被減弱；此外，estrogen-related receptor (ERR)-alpha 及 PGC-1alpha 的表現量則會因為高糖誘導而增加，但 AEPP 則能抑制這兩個參與粒線體活化的分子表現。綜合以上結果可知 AEPP 可降低 OVCAR-3 卵巢癌細胞中的 PGC-1alpha 表現以抑制細胞存活與 EMT 現象。這些現象同樣可在 PGC-1alpha knockdown 的 OVCAR-3 卵巢癌細胞中發生同樣結果，顯示 AEPP 具有開發做為協同治療卵巢癌細胞增生與轉移的潛力。
The current chemotherapy is the main approach to deal with advanced ovarian cancer but the limitations includes drug insensitive and resistance on individuals and undesired adverse effects which worsen life quality of patients resulted in the poor clinical outcomes in practice. Cancer stem cells (CSCs) escape chemotherapy and lead to chemoresistance. The cancer therapies include surgery, chemotherapy, radiation therapy and immunotherapy. However, patients would have a great burden on the body and must endure pains from side effects of drugs during therapies. To improve patient’s living quality, many efforts are focused on searching alternative therapies or synergy with drugs that can reduce the patient’s suffering.
Traditional Chinese medicine such as Paris polyphylla and Cordyceps militaris have been found to suppress proliferation and induce apoptosis in cancer cells, but the development of drug ressitance and cancer stemness in ovarian carcinoma cells treatedy by Paris polyphylla and Cordyceps militaris are unclear. Cordycepin (3′-deoxyadenosine) is an antitumor compound that has been found to exert antiangiogenic, antimetastatic, and antiproliferative effects in addition to inducing apoptosis. However, the association between migration and mitochondrial function in cordycepin-treated ovarian carcinoma cells is unknown. We investigated the suppressions of epithelial-mesenchymal transition (EMT) and mitochondrial function in human ovarian carcinoma cell lines treated by AEPP or cordycepin. The mitochondrial morphology was investigated using MitoTracker Deep Red FM staining. We found that cordycepin (noncytotoxic concentrations at 50 and 100 μM) potentially lowered mitochondrial fusion and induces mitochondrial fission, suggesting that cordycepin inhibits EMT and migration in ovarian carcinoma cells. Moreover, we evaluated that these effects contributed to the inhibition of estrogen-related receptor (ERR)-alpha by cordycepin treatment. This is the first study to figure out the inhibition of metastasis and migration in ovarian carcinoma cells through the downregulation of mitochondrial activity mediated by cordycepin induction. Finally, we evaluated the benefit effects of cordycepin on antimetastasis and antimigration in ovarian cancer therapy. We previously demonstrated that cordycepin suppressed metastasis in human ovarian carcinoma cells, the aim of this study is further to evaluate the effects of cordycepin on ovarian cancer stemness. Currently, TGF-beta was used to induce chemoresistance against chemotherapeutic agent cisplatin in SKOV-3 ovarian cancer cells. We found that the cell viability, the percentage of cancer stem cells, and the levels of matrix metalloproteinases (MMPs) were decreased in TGF-beta-induced SKOV-3 cells after treating with 100 M of cordycepin. Moreover, TGF-beta induction significantly elevated the expression of vimentin and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1alpha), and decreased E-cadherin levels in SKOV-3 cells, but cordycepin recovered E-cadherin and inhibited vimentin, indicating that the down-regulation of cancer stmness by cordycepin may be contributed to the EMT suppression.
On the other hand, we alos found AEPP reduced OVCAR-3 cell viability considerably through induction of apoptosis, but this inhibitory potential of AEPP was attenuated by high glucose (HG) induction in OVCAR-3 cells. Results demonstrated that the levels of ERR-alpha activator and PGC-1alpha were elevated by HG induction, but were inhibited by AEPP. Due to down-regulations of cell survival and EMT were oberved in OVCAR-3 cells through suppression of PGC-1alpha by AEPP treatment; therefore, this result was confirmed through PGC-1alpha knockdown and overexpression in OVCAR-3 cells. Taken together, AEPP can be beneficial for treating ovarian cancer and has potential for development of an integrative cancer therapy against ovarian cancer proliferation, metastasis, and migration. Similarly, cordycepin efficiently attenuated chemoresistance caused by TGF-beta in SKOV-3 cancer stem cells to promote the cytotoxicity of cisplatin. |
