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G-protein-coupled receptor 40 (GPR40) and GPR120 mediate a variety of biological functions by the binding of long and medium chain free fatty acids. In the present study, we investigated a role of GPR40 in the pathogenesis of fibrosarcoma HT1080 cells. The GPR40 gene expression was detected in HT1080 cells, but not the GPR120 gene. The cell motile and invasive activities were markedly enhanced by GPR40 knockdown, compared with control cells. To evaluate whether GPR40 is involved in the cellular functions of HT1080 cells during anticancer drug treatment, HT1080 cells were maintained in condition medium containing cisplatin (CDDP) (0.01-1.0 μM) for 6 mo. The expression levels of the GPR40 gene was elevated by the long-term CDDP treatment in HT1080 cells, while the GPR120 gene expression remained unchanged. The cell motile and invasive activities of HT1080 cells treated with CDDP were significantly lower than those of untreated cells. In gelatin zymography, the activities of matrix metalloproteinase-2 (MMP-2) and MMP-9 of HT1080 cells were enhanced by the long-term CDDP treatment. In addition, GW9508 which is an agonist of GPR40 and GPR120 suppressed the cell motile and invasive activities of HT1080 cells treated with CDDP as well as the MMP activation. These results suggest that GPR40 negatively regulates the tumor progression of fibrosarcoma cells. © 2015 Wiley Periodicals, Inc.

Summary Embryonic vascular development is achieved through the complex arrays of differentiation, proliferation, migration and mutual interaction of different cell types, and visualization as well as purification of unique cell populations are fundamental in studying its detailed mechanisms using in vivo experimental models. We previously demonstrated that Tmem100 was a novel endothelial gene encoding a small transmembrane protein, and that Tmem100 null mice showed embryonic lethality due to severe impairment of vascular formation. In the present study, we generated an EGFP reporter mouse line using a 216 kb genomic region containing mouse Tmem100 gene. A novel line designated as Tmem100‐BAC‐EGFP mice precisely recapitulated the Tmem100 expression profile at the mid‐gestational stage, which was highly enriched in endothelial cells of large caliber arteries in mouse embryos. FACS experiments demonstrated that Tmem100‐BAC‐EGFP mice served to selectively purify a specific population of arterial endothelial cells, indicating their usefulness not only for the research concerning Tmem100 expression and function but also for comparative analysis of multiple endothelial cell subgroups in embryonic vascular development.

Lysophosphatidic acid (LPA) signaling via LPA receptors provides a variety of cellular functions, including angiogenesis. In this study, to assess an involvement of LPA receptors in cell motile activities of endothelial cells during chemotherapy, F-2 cells were treated with cisplatin (CDDP) and doxorubicin (DOX) at a concentration of 0.01 μM every 24 h for at least 1 month. The treatment of CDDP and DOX inhibited the expression levels of the LPA receptor-1 (Lpar1), Lpar2, and Lpar3 genes in F-2 cells. The cell motile activities of CDDP and DOX treated cells were relatively lower than those of untreated cells. Next, we investigated whether cancer cells could stimulate the cell motile activities of F-2 cells treated with CDDP and DOX. For cell motility assay, CDDP- and DOX-treated cells were co-cultured with pancreatic cancer PANC-1 cells. The cell motile activities of CDDP- and DOX-treated cells were significantly enhanced by the existence of PANC-1 cells, correlating with the LPA receptor expressions. In addition, the elevated cell motile activities were suppressed by the pretreatment of an autotaxin inhibitor S32826. These results suggest that LPA signaling via LPA receptors may regulate the cell motile activities of F-2 cells treated with anticancer drugs.