Huang Lu, Xu Shanshan, Hu Dongxiao, Lu Weiguo, Xie Xing, Cheng Xiaodong
*Women's Reproductive Health Laboratory of Zhejiang Province, and †Department of Gynecologic Oncology, Women's Hospital School of Medicine, Zhejiang University, Hangzhou, China.
Int J Gynecol Cancer. 2015 May;25(4):559-65. doi: 10.1097/IGC.0000000000000394.
Wide metastasis is one of characteristics of ovarian cancer. Cancer stem cells, as a source in cancer invasion and metastasis, possess powerful potential of differentiation. Scaffolding IQ domain GTPase-activating protein 1 (IQGAP1) plays a key role in the invasion and metastasis of cancer cells, but IQGAP1's role in cancer stem cells including ovarian cancer was unclear.
Spheroid culture with serum-free medium was used for enriching ovarian cancer stem cell-like cells (CSC-LCs) from 3AO cell line, and a medium with 10% fetal bovine serum was used to induce the differentiation of CSC-LCs. Immunofluorescence was for detecting the stem markers OCT4 and SOX2. The quantitative real-time-polymerase chain reaction and Western blotting were performed to determine the messenger RNA and protein expression of IQGAP1, respectively. The capacity of cell invasion was evaluated by transwell chamber assay.
Ovarian CSC-LCs obtained through spheroid culture showed irregularly elongated appearance, CD24 negative, and OCT4 and SOX2 positive. IQGAP1 expression was decreased in ovarian CSC-LCs compared with parental 3AO cells, but increased de novo during the differentiation of CSC-LCs. Knockdown of IQGAP1 by specific small interfering RNA remarkably weakened invasion capacity of 2-day differentiated ovarian CSC-LCs.
Increased IQGAP1 expression during the differentiation of CSC-LCs is involved in an aggressive cell behavior, which may contribute to metastasis of ovarian cancer.
广泛转移是卵巢癌的特征之一。癌症干细胞作为癌症侵袭和转移的根源，具有强大的分化潜能。支架IQ结构域GTP酶激活蛋白1（IQGAP1）在癌细胞的侵袭和转移中起关键作用，但IQGAP1在包括卵巢癌在内的癌症干细胞中的作用尚不清楚。
采用无血清培养基进行球状体培养，从3AO细胞系中富集卵巢癌干细胞样细胞（CSC-LCs），并用含10%胎牛血清的培养基诱导CSC-LCs分化。免疫荧光法检测干细胞标志物OCT4和SOX2。分别采用定量实时聚合酶链反应和蛋白质印迹法测定IQGAP1的信使核糖核酸和蛋白表达。通过Transwell小室实验评估细胞侵袭能力。
通过球状体培养获得的卵巢CSC-LCs呈不规则细长外观，CD24阴性，OCT4和SOX2阳性。与亲代3AO细胞相比，卵巢CSC-LCs中IQGAP1表达降低，但在CSC-LCs分化过程中重新升高。用特异性小干扰RNA敲低IQGAP1可显著削弱2天分化的卵巢CSC-LCs的侵袭能力。
CSC-LCs分化过程中IQGAP1表达增加与侵袭性细胞行为有关，这可能促进卵巢癌转移。
