Human Adipose Tissue-derived Mesenchymal Stem Cells Inhibit Melanoma Growth In Vitro and In Vivo

Background/Aim: The effects of adipose tissue- derived mesenchymal stem cells (AT-MSCs) on the growth of human malignancies, including melanoma, are controversial and the underlying mechanisms are not yet-well understood. The aim of the present study was to investigate the in vitro and in vivo anti-tumor effects of human AT-MSCs on human melanoma. Materials and Methods: The inhibitory effect of AT-MSC-conditioned medium (AT-MSC-CM) on the growth of A375SM and A375P (human melanoma) cells was evaluated using a cell viability assay. Cell-cycle arrest and apoptosis in melanoma cells were investigated by flow cytometry and western blot analysis. To evaluate the in vivo anti-tumor effect of AT-MSCs, CM-DiI-labeled AT-MSCs were circumtumorally injected in tumor-bearing athymic mice and tumor size was measured. Results: AT-MSC-CM inhibited melanoma growth by altering cell-cycle distribution and inducing apoptosis in vitro. AT-MSCs suppressed tumor growth in tumor-bearing athymic mice and fluorescence analysis showed that AT-MSCs migrated efficiently to tumor tissues. Conclusion: AT-MSCs inhibit the growth of melanoma suggesting promise as a novel therapeutic agent for melanoma. Although melanoma accounts for less than 10% of all skin cancers, malignant melanoma is an aggressive disease that accounts for 75% of skin cancer-related deaths (1). The incidence rates of melanoma in the USA have been continuously increasing in the last few decades, with the incidence estimated to be 76,690 new melanoma cases and