Department of Surgical Oncology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, Japan.
Int J Cancer. 2014 Apr 15;134(8):1785-95. doi: 10.1002/ijc.28520. Epub 2013 Oct 24.
Cancer-associated fibroblasts (CAFs) have recently been implicated in tumor growth and metastasis in gastric cancer. Cancer stem cells (CSCs) have been proposed to have an important role in cancer progression. The aim of this study was to clarify the effect of CAFs on CSCs characteristics in gastric carcinoma. Scirrhous gastric cancer cell lines, OCUM-12 and OCUM-2MD3, and non-scirrhous gastric cancer cell lines, MKN-45 and MKN-74, were used. OCUM-12/side population (SP) cells and OCUM-2MD3/SP cells were sorted by flow cytometry as CSC-rich cells from the parent cells. CaF-37 was established from the tumoral gastric specimens as CAFs. Flow cytometric analysis of SP fraction, spheroid colony assay, and RT-PCR analysis of CSC markers were performed to identify CSCs properties. Effect of CAFs on the tumorigenicity by OCUM-12/SP cells was examined using nude mice. CAF CM significantly increased the percentages of the SP fraction of OCUM-12/SP and OCUM-2MD3/SP cells, but not that of MKN-45/SP and MKN-74/SP cells. Taken together, CM from CaF-37 significantly increased the number of spheroid colonies and the expression level of CSC markers of OCUM-12/SP and OCUM-2MD3/SP cells. These stimulating-activities by CM were significantly decreased by TGFβ inhibitors, but not FGFR and cMet inhibitor. Tumorigenicity by subcutaneous coinoculation of OCUM-12/SP cells with CAFs was significantly high in comparison with that by OCUM-12/SP cells alone. Phospho-Smad2 expression level was significantly increased by co-inoculation with CAFs. These findings suggested that CAFs might regulate the stemness of CSCs in scirrhous gastric cancer by TGFβ signaling.
癌症相关成纤维细胞 (CAFs) 最近被认为与胃癌的肿瘤生长和转移有关。癌症干细胞 (CSCs) 被认为在癌症进展中起着重要作用。本研究旨在阐明 CAFs 对胃癌中 CSCs 特征的影响。使用了弥漫型胃癌细胞系 OCUM-12 和 OCUM-2MD3 以及非弥漫型胃癌细胞系 MKN-45 和 MKN-74。通过流式细胞术从亲本细胞中对 OCUM-12/侧群 (SP) 细胞和 OCUM-2MD3/SP 细胞进行分选，作为富含 CSC 的细胞。从肿瘤性胃标本中建立了 CaF-37 作为 CAFs。通过 SP 分数的流式细胞分析、球体集落形成测定和 CSC 标志物的 RT-PCR 分析来鉴定 CSCs 特性。使用裸鼠检查 CAFs 对 OCUM-12/SP 细胞的致瘤性的影响。CAF CM 显著增加了 OCUM-12/SP 和 OCUM-2MD3/SP 细胞的 SP 分数百分比，但对 MKN-45/SP 和 MKN-74/SP 细胞没有影响。总之，CaF-37 的 CM 显著增加了 OCUM-12/SP 和 OCUM-2MD3/SP 细胞的球体集落数量和 CSC 标志物的表达水平。这些由 CM 引起的刺激活性通过 TGFβ 抑制剂显著降低，但 FGFR 和 cMet 抑制剂没有降低。与 OCUM-12/SP 细胞单独接种相比，OCUM-12/SP 细胞与 CAFs 皮下共接种的致瘤性显著升高。共接种 CAFs 后磷酸化 Smad2 的表达水平显著增加。这些发现表明，CAFs 可能通过 TGFβ 信号调节弥漫型胃癌中 CSCs 的干性。
