P16 Hydrogen sulfide stimulates colorectal cancer-associated fibroblast proliferation and migration

Cells in the stromal microenvironment facilitate colorectal cancer progression and “co-evolve” with the malignant epithelial cells. It is well established that the tumor stroma contributes to the growth and metastatic spread of colorectal cancer. We have recently reported that colorectal cancer cells (CRC) express high levels of cystathionine-β-synthetase (CBS) and produce high amounts of hydrogen sulfide (H2S) when compared to the normal adjacent colonic epithelium. However, the effects of CRC-derived H2S on CRC-associated fibroblast (CAF) activity are unknown. The aim of this study was to determine whether H2S stimulates CAF proliferation and/or migration. Human CAFs from CRC were collected under an IRB-approved protocol and cultured. The xCELLigence system was used to assess cell proliferation for 144 h. For migration assays, 10[5] CAFs were suspended in serum-free media containing 0.1% BSA and added to 8 μm pore Transwell chambers. Cells were allowed to migrate toward the bottom chamber containing tumor cell conditioned media (CM) either with or without the slow-release H2S donor GYY4137. Migrated cells were quantified by visual counting. The results showed that GYY4137 (30 μM–3 mM) significantly increased CAF proliferation. Moreover, GYY4137 (1 mM) enhanced the migration of CAFs toward tumor-conditioned medium. Thus, the data demonstrate that H2S enhances CAF cell proliferation and migration in vitro. We hypothesize that cancer cell-derived H2S may play a role in promoting CAF proliferation and this effect may be part of a complex system of reciprocal interactions between fibroblasts and cancer cells important for tumor progression and spread.