MiR-125a-3p negatively regulates osteoblastic differentiation of human adipose derived mesenchymal stem cells by targeting Smad4 and Jak1

Osteogenesis is a complex process which relies on the coordination of signals and transcription factors. Recent evidence indicates that microRNAs (miRNAs) act as important post-transcriptional regulators in a large number of biological processes including osteoblast differentiation. In this study, we investigated the expression and biological effect of miR-125a-3p during osteogenic differentiation of human adipose derived mesenchymal stem cells (hADSCs). We observed an obvious decrease in miR-125a-3p level during osteogenic differentiation. By using gain- and loss-of function experiments, we noticed that miR-125a-3p could suppress the osteogenic differentiation of hADSCs. Moreover, miR-125a-3p over-expression in hADSCs by transfection with miR-125a-3p mimics significantly inhibited cell proliferation by MTT. Flow cytometry analysis further demonstrated that forced expression of miR-125a-3p induced cell cycle G₁/S phase arrest and apoptosis. In addition, we performed bioinformatic analysis, luciferase reporter assay and western blot to confirm that miR-125a-3p could regulate Smad4 and Jak1 expression negatively. Meanwhile, Smad4 and Jak1 were up-regulated after osteogenic differentiation and the down-regulation of endogenous Smad4 and Jak1 suppressed the osteogenic differentiation of hADSCs. Taken together, these data indicated that miR-125a-3p is Smad4 and Jak1 regulator, and it has a crucially physiological function in osteogenic differentiation of hADSCs.

The therapeutic potential of human adipose-derived mesenchymal stem cells producing CXCL10 in a mouse melanoma lung metastasis model

Interferon γ-induced protein 10 kDa (IP-10) is a potent chemoattractant and has been suggested to enhance antitumor activity and mediate tumor regression through multiple mechanisms of action. Multiple lines of evidence have indicated that genetically-modified adult stem cells represent a potential source for cell-based cancer therapy. In the current study, we assessed therapeutic potential of human adipose derived mesenchymal stem cells (hADSC) genetically-modified to express IP-10 for the treatment of lung metastasis in an immunocompetent mouse model of metastatic melanoma. A Piggybac vector encoding IP-10 was employed to transfect hADSC ex vivo. Expression and bioactivity of the transgenic protein from hADSCs expressing IP-10 were confirmed prior to in vivo studies. Our results indicated that hADSCs expressing IP-10 could inhibit the growth of B16F10 melanoma cells and significantly prolonged survival. Immunohistochemistry analysis, TUNEL assay and western blot analysis indicated that hADSCs expressing IP-10 inhibited tumor cell growth, hindered tumor infiltration of Tregs, restricted angiogenesis and significantly prolonged survival. In conclusion, our results demonstrated that targeting metastatic tumor sites by hADSC expressing IP-10 could reduce melanoma tumor growth and lung metastasis.