Massachusetts General Hospital Cancer Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
PLoS One. 2012;7(1):e29079. doi: 10.1371/journal.pone.0029079. Epub 2012 Jan 17.
Identification of gene expression profiles of cancer stem cells may have significant implications in the understanding of tumor biology and for the design of novel treatments targeted toward these cells. Here we report a potential ovarian cancer stem cell gene expression profile from isolated side population of fresh ascites obtained from women with high-grade advanced stage papillary serous ovarian adenocarcinoma. Affymetrix U133 Plus 2.0 microarrays were used to interrogate the differentially expressed genes between side population (SP) and main population (MP), and the results were analyzed by paired T-test using BRB-ArrayTools. We identified 138 up-regulated and 302 down-regulated genes that were differentially expressed between all 10 SP/MP pairs. Microarray data was validated using qRT-PCR and17/19 (89.5%) genes showed robust correlations between microarray and qRT-PCR expression data. The Pathway Studio analysis identified several genes involved in cell survival, differentiation, proliferation, and apoptosis which are unique to SP cells and a mechanism for the activation of Notch signaling is identified. To validate these findings, we have identified and isolated SP cells enriched for cancer stem cells from human ovarian cancer cell lines. The SP populations were having a higher colony forming efficiency in comparison to its MP counterpart and also capable of sustained expansion and differentiation in to SP and MP phenotypes. 50,000 SP cells produced tumor in nude mice whereas the same number of MP cells failed to give any tumor at 8 weeks after injection. The SP cells demonstrated a dose dependent sensitivity to specific γ-secretase inhibitors implicating the role of Notch signaling pathway in SP cell survival. Further the generated SP gene list was found to be enriched in recurrent ovarian cancer tumors.
鉴定癌症干细胞的基因表达谱可能对理解肿瘤生物学具有重要意义，并为针对这些细胞的新型治疗方法的设计提供依据。本研究报告了从高级别晚期乳头状浆液性卵巢腺癌患者的新鲜腹水分离的侧群中鉴定出的潜在卵巢癌干细胞基因表达谱。使用 Affymetrix U133 Plus 2.0 微阵列来检测侧群（SP）和主群（MP）之间差异表达的基因，使用 BRB-ArrayTools 对配对 T 检验的结果进行分析。我们鉴定了 10 对 SP/MP 之间差异表达的 138 个上调基因和 302 个下调基因。使用 qRT-PCR 对微阵列数据进行验证，17/19（89.5%）个基因的微阵列和 qRT-PCR 表达数据之间具有很强的相关性。Pathway Studio 分析鉴定了一些涉及细胞存活、分化、增殖和凋亡的基因，这些基因是 SP 细胞所特有的，并且鉴定出 Notch 信号通路的激活机制。为了验证这些发现，我们已经从人卵巢癌细胞系中鉴定和分离了富含癌症干细胞的 SP 细胞。与 MP 相比，SP 群体的集落形成效率更高，并且能够持续扩增和分化为 SP 和 MP 表型。50,000 个 SP 细胞在裸鼠中产生肿瘤，而相同数量的 MP 细胞在注射后 8 周内未能产生任何肿瘤。SP 细胞对特定 γ-分泌酶抑制剂表现出剂量依赖性敏感性，表明 Notch 信号通路在 SP 细胞存活中起作用。进一步发现生成的 SP 基因列表在复发性卵巢癌肿瘤中富集。
