Spheroid colony formation is a typically method to identify cancer stem cells (CSC). The growth of spherical colonies is considered indicative of self-renewal ability, and is consistent with a CSC phenotype. However, mechanism of spheroid formation remains unclear in gastric cancer (GC). In the present study, we analyzed spheroid formation associated genes in GC. Comprehensive gene expression profile of MKN-45 and MKN-74 GC cell lines that were grown as monolayers or spheroids was obtained by Affymetrix GeneChip, and we found several kinds of genes whose expression was up-regulated or down-regulated in cells that were grown as spheroids. Among these, 10 kinds of kinesin genes were up-regulated in both MKN-45 and MKN-74 cells that were grown as spheroids. Kinesins are categorized into 14 subfamilies and classified as mitotic kinesins, which are involved in cell division, and non-mitotic kinesins, which are principally involved in intracellular transport. In spheroids, mitotic kinesins were up-regulated. In the present study, we focused on KIFC1, because antibody against KIFC1 is available. qRT-PCR analysis revealed that up-regulation of KIFC1 in both MKN-45 and MKN-74 cells that were grown as spheroids. Immunohistochemical analysis of KIFC1 was performed in 20 GC cases. Expression of KIFC1 was up-regulated in GC tissues in comparison with corresponding non-neoplastic mucosa. These results suggest that KIFC1 plays an important role in gastric carcinogenesis and may be a therapeutic target of GC.

Citation Format: Naohide Oue, Shoichiro Mukai, Trang Pham T.B., Kazuhiro Sentani, Reiko Ito, Wataru Yasui. Significance of KIFC1 in spheroid formation of gastric cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1413. doi:10.1158/1538-7445.AM2015-1413