熊果酸对卵巢癌干细胞荷瘤裸鼠耐药的逆转作用

Reversing effects of ursolic acid on drug resistance in nude mice bearing ovarian cancer stem cells

目的探讨熊果酸对于卵巢癌干细胞荷瘤裸鼠耐药的逆转作用。方法选用人卵巢癌Skov3细胞通过无血清悬浮培养法富集干细胞,接种于裸鼠皮下,建立裸鼠人卵巢癌干细胞皮下移植瘤耐药模型。随机分为Skov3贴壁细胞组、干细胞组,熊果酸高、中、低剂量组,顺铂组,顺铂联合熊果酸组。连续给药14天,空白组给予0.9%Na Cl溶液。每天测量瘤体积,绘制肿瘤生长曲线,计算抑瘤率。给药结束后,取肿瘤组织,HE染色观察肿瘤细胞形态、结构,免疫组化检测ABCG2的表达,TUNEL法检测凋亡细胞。结果熊果酸可以抑制肿瘤组织生长,并且抑瘤率随剂量增加而上升,熊果酸与顺铂联用明显优于顺铂(P<0.01)。不同剂量的熊果酸干预后,ABCG2的表达下调,肿瘤干细胞凋亡增多,均具有剂量依赖性。并且熊果酸联合顺铂组较单用顺铂组,ABCG2的表达明显被抑制,细胞凋亡数明显升高。结论熊果酸可以抑制卵巢癌干细胞荷瘤裸鼠的瘤体生长,通过下调耐药指标ABCG2,促进细胞凋亡,提高顺铂诱导的细胞凋亡来达到逆转耐药的作用。

Objective To investigate the reversing effects and mechanism of ursolic acid on drug resistance in nude mice bearing ovarian cancer stem cel}s. Methods The human ovarian cancer stem cells were enriched and collected from serum free cells suspension of Skov3 cells. Then the cells were inoculated subcutaneously into nude mice. The nude mice were treated with ursolic acid （high, medium and low dose）, cisplatin, andcisplatin plus ursolic acid respectively for 14 continuous days. Tumor growth curve and inhibitory rate were calculated by daily t of tumor volume. Cell morphology and structure were observed by HE staining; ABCG2 expression was detected by immunohistochemistry and cell apoptosis was detected by the TUNEL method. Results Ursolic acid inhibited tumor growth in a dose-dependent manner, and nrsolic acid plus cisplatin group was superior to cisplatin group. Ursolic acid inhibited the expression of ABCG2, a drug rsisitance index, and promoted apoptosis of cancer stem cells, improved the ability of cisplatin-induced apoptosis. Conclusion Ursolic acid can inhibit the tumor growth in nude mice transplanted with ovarian cancer stem cells by decreasing ABCG2 expression, promoting cell apoptosis, enhancing cisplatin- induced apoptosis.