Abstract 1495: Role of stromal fibroblasts in the progression of esophageal squamous cell carcinoma
Authors: Saito Shin , Morishima Kazue , Matsubara Daisuke , Hosoya Yoshinori , Sata Naohiro , Yasuda Yoshikazu , Niki Toshiro 
Published: August 2012

Objectives: The prevalence of esophageal squamous-cell carcinoma (ESCC) is high in Asia, including Japan. Cancer results from the accumulated effects of many genetic alterations. However, the microenvironment of cancer cells has recently been shown to strongly influence the biologic properties of cancer. In this study, we focused on interrelations between cancer and fibroblasts, the main component of cancer stroma. Methods: We purchased 22 cell lines of esophageal squamous-cell carcinoma from RIKEN Cell Bank and the Japanese Collection of Research Bioresources. For fibroblasts we used human esophageal fibroblasts isolated from surgical specimens. To examine interactions between esophageal squamous-cell carcinoma and fibroblasts, the following in vitro experiments were performed: 1) cell proliferation assays; 2) cell migration assays; 3) 3-dimensional organotypic culture; and 4) time-lapse cinematography of 3-dimentional culture. For in vivo experiments, cancer cells and fibroblasts were co-transplanted subcutaneously in NOD/SCID mice to assess the effects of fibroblasts on tumorigenicity. We also retrospectively analyzed 97 ESCC patients to study the relationship between tumor stroma and pathological findings. Results: Fibroblast culture supernatant increased the cell count in 14 of 22 cell lines. The stimulating effect of fibroblast supernatant could be explained by various growth factors and cytokines; HGF and IL-6 stimulated the proliferation of 6 and 5 cancer cell lines, respectively, while FGF1, FGF7, and FGF10 increased cell proliferation of 7, 6, and 6 cancer cell lines, respectively. When the MET inhibitor PHA-665752 was added to the fibroblast culture supernatant, the culture supernatant-induced proliferation of was abrogated in 2 cell lines. Among 10 cell lines whose proliferation was induced by FGFs, addition of FGFR inhibitor PD-173074 to the fibroblast culture supernatant abrogated the effect of the culture supernatant in 4 cell lines. In migration assays, the presence of fibroblasts significantly increased the migration of cancer cells in 3 of 6 representative cell lines. In organotypic culture, stromal invasion was seen only in presence of fibroblasts. Time-lapse cinematography confirmed that clusters of cancer cells progressively migrated towards the fibroblast meshwork. In vivo tumor growth was promoted by co-injection of fibroblasts in 13 of 22 cancer cell lines. In clinicopathological study, the extent of stromal fibrosis was significantly related to depth of invasion and venous invasion of tumor cells. Conclusion: In many esophageal cancer cell lines, cell proliferation was promoted by the presence of fibroblasts both in vivo and in vitro. The stimulatory effect of fibroblast could be accounted for by various growth factors and cytokines, such as HGF, interleukin-6 and/or FGFs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1495. doi:1538-7445.AM2012-1495