黃連素(berberine)，屬於異奎碄類(isoquinoline)植物性生物鹼(alkaloid），已在生物及藥理活性上廣泛被研究。黃連素可藉由抑制腫瘤細胞的生長週期，DNA和蛋白質的合成和降低拓撲異構?(topoisomerase)的活性，而抑制許多癌細胞的生長，近年來也有文獻指出，黃連素能通過調節凋亡基因的表達以及降低粒線體跨膜電位而促進腫瘤細胞凋亡。但對於黃連素抑制由腫瘤所誘導的血管新生作用，目前還不是很清楚。在本篇我們發現人類子宮頸癌細胞SiHa處理黃連素之後可以抑制血管新生情形。我們分析了在腫瘤微環境的影響下所產生HIF-1α與大量分泌血管生長因子 (VEGF)，在處理了黃連素利用ELISA、 Western blot分析發現隨者藥物濃度的增加明顯抑制了HIF-1α蛋白表現量、進而使VEGF分泌與蛋白表現量減少，並抑制了血管管柱的形成。另外我們又單獨分析人類血管內皮細胞 (HUVECs) 在黃連素處理下，利用gelatin zymography與casein zymography進行實驗發現黃連素可以有效的抑制MMP-2、u-PA的分泌量以及蛋白表現量。接著利用Western blot 實驗來分析黃連素抑制血管新生之路徑，在p38、Erk1/2的磷酸化程度受到明顯的抑制，因此可知黃連素可能透過抑制MAPK pathway 導致MMP-2與u-PA的表現減少及抑制血管新生的能力。接著利用雞胚絨毛尿囊膜體內試驗證實，在黃連素的處理下明顯抑制血管新生的現象。綜合以上結論，黃連素是一種具有預防或輔助治療上抑制癌症血管新生與在未來發展為抗人類子宮頸癌抗癌藥物的潛力。 Berberine is a medically important isoquinoline alkaloid which exists in a number of medicinal plants and displays a broad array of pharmacological effects. Studies have indicated that berberine could inhibit the growth of various cancer cell lines. It is due to suppression of the cell cycles, inhibition of DNA, protein synthesis of tumor cells and repression of the topoisomerase activities. In order to obtain more specific understandings of those consequences of berberine on SiHa cell (cervical cancer cells line) and the microenvironment of tumor cells, we conducted in vitro experiments to investigate the inhibitory effects of berberine on tumor-induced angiogenesis using SiHa cell and human umbilical vein endothelial cells (HUVECs). Using ELISA analysis found that berberine could reduce secretion of VEGF in SiHa cells. Parallel Western blot analyses revealed that berberine prevented SiHa cultures from expressing vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1, two key factors in mediating tumor angiogenesis. Berberine inhibited the capacity of SiHa cell to stimulate HUVEC’s invasion and endothelial tube formation. We further analyzed the inhibition effects of berberine on HUVECs. We assayed matrix metalloproteinases (MMPs) and urokinase-plasminogen activator (u-PA) activities of HUVECs via Western blotting, RT-PCR, gelatin zymography, and casein zymography. Berberine significantly inhibited the secretion, and the expression of mRNA and protein levels of MMP-2 and u-PA. Berberine inhibited phosphorylation of ERK1/2 and p38 by Western blot analysis. Berberine also suppressed the cell invasion on HUVECs. The chick chorioallantoic membrane in vivo tests confirmed that berberine treatment significantly inhibited the angiogenesis phenomenon. In conclusion, these findings strongly suggest that berberine is a potential antiangiogenic agent and a promising antitumor drug for cervical cancer.
