TLR3 stimulation improves the migratory potency of adipose-derived mesenchymal stem cells through the stress response pathway in the melanoma mouse model.

BACKGROUND: Mesenchymal stem cells (MSCs) are utilized as a carrier of anti-tumor agents in targeted anti-cancer therapy. Despite the improvements in this area, there are still some unsolved issues in determining the appropriate dose, method of administration and biodistribution of MSCs. The current study aimed to determine the influence of toll-like receptor 3 (TLR3) stimulation on the potential of MSCs migration to the neoplasm environment in the mouse melanoma model. METHODS AND RESULTS: Adipose-derived MSCs (ADMSCs) were isolated from the GFP+ transgenic C57BL/6 mouse and treated with different doses (1 µg/ml and 10 µg/ml) of polyinosinic-polycytidylic acid, the related TLR3 agonist, at various time points (1 and 4 h). Following the treatment, the expression of targeted genes such as α4, α5, and ß1 integrins and TGF-ß and IL-10 anti-inflammatory cytokines was determined using real-time PCR. In vivo live imaging evaluated the migration index of the intraperitoneally (IP) injected treated ADMSCs in a lung tumor-bearing mouse (C57BL/6) melanoma model (n = 5). The presented findings demonstrated that TLR3 stimulation enhanced both migration of ADMSCs to the tumor area compared with control group (n = 5) and expression of α4, α5, and ß1 integrins. It was also detected that the engagement of TLR3 resulted in the anti-inflammatory behavior of the cells, which might influence the directed movement of ADMSCs. CONCLUSION: This research identified that TLR3 activation might improve the migration via the stimulation of stress response in the cells and depending on the agonist concentration and time exposure, this activated pathway drives the migratory behavior of MSCs.

The effect of poly I:C or LPS priming on the therapeutic efficacy of mesenchymal stem cells in an adjuvant-induced arthritis rat model.

BACKGROUND: The immunomodulatory properties of mesenchymal stem cells (MSCs) have made them a prospective treatment option for inflammatory and autoimmune disorders. Recent studies have found an association between the immunomodulatory function of MSCs and Toll-like receptors (TLRs). Here, we investigated the effect of priming with lipopolysaccharide (LPS) as TLR4 ligand or polyinosinic:polycytidylic acid (poly I:C) as TLR3 ligand on the immunomodulatory function of adipose-derived MSCs (ADMSCs) in vitro and for the first time in an adjuvant-induced arthritis model (AIA). METHODS: ADMSCs were treated with LPS or poly I:C for 1 h. Splenocyte proliferation in the presence of primed ADMSCs was assessed in vitro using an MTT assay. Next, we investigated the therapeutic effect of primed ADMSCs in vivo. Male Wistar rats were infused with complete Freund's adjuvant (CFA) to develop arthritis and then intraperitoneally treated with not-primed, poly I:C- or LPS-primed ADMSCs. Clinical signs, histopathological alteration, and serum and spleen cytokine levels were analyzed. RESULTS: Poly I:C-primed ADMSCs significantly reduced splenocytes proliferation, while ADMSCs primed with LPS increased splenocytes proliferation. Furthermore, poly I:C-primed ADMSCs significantly alleviated the clinical and histopathological severity and the secretion of inflammatory cytokines associated with Th17/Th1 such as IL-17 and IFN-γ. Poly I:C-primed ADMSCs also increased cytokines IL-10 and TGF-ß. TNF-α and IL-6 Levels were also markedly diminished in the serum of AIA animals treated with poly I:C-primed ADMSCs. In contrast, priming ADMSCs with LPS significantly reduced the therapeutic effect of ADMSCs in AIA animals. CONCLUSION: As a result of these findings, poly I:C priming may be a new technique for improving the therapeutic effects of MSCs in arthritic disorders.

Comparative gene-expression profiling of CD133(+) and CD133(-) D10 melanoma cells.

AIMS: The present study aimed to compare the gene-expression profiling of CD133(+) and CD133(-) D10 cells. MATERIALS & METHODS: Cancer stem cell-like properties and gene-expression profiling of CD133(+) D10 cells versus CD133(-) cells were evaluated. RESULTS: The CD133(+) D10 cells showed significantly higher clonogenic and spheroid forming potential, also higher expression of stemness genes NANOG and OCT4A compared with the CD133(-) cells. Gene-expression profiling of CD133(+) versus CD133(-) D10 cells revealed that 130 genes including ABC transporter superfamily (ABCC1, ABCG2 and ABCC6) were upregulated, while 61 genes including apoptosis modifying genes (CASP8 and TNFRSF4) were downregulated. CONCLUSION: We conclude that many genes involved in drug resistance and tumor aggressiveness are upregulated in CD133(+) D10 cells and targeting them might be an efficient strategy for treatment of melanoma.

Evaluation of the expressions pattern of miR-10b, 21, 200c, 373 and 520c to find the correlation between epithelial-to-mesenchymal transition and melanoma stem cell potential in isolated cancer stem cells.

Small non-coding RNAs named microRNAs (miRNAs) modulate some functions and signaling pathways in skin epithelial cells and melanocytes. They also function as oncogenes or tumor suppressors in malignancies and tumor metastasis. We investigated the expression patterns of miRNAs, including miR-10b, 21, 200c, 373 and 520c, which regulate epithelial-to-mesenchymal transition (EMT) and metastasis in isolated cancer stem cells (CSCs) and non- CSCs. Six melanoma cell lines were tested for the expressions of stem cell markers. Melanoma stem cells were enriched via fluorescence-activated cell sorting (FACS) using the CD133 cell surface marker or spheroid culture. They were then characterized based on colony and sphere formation, and the expressions of stemness and EMT regulator genes and their invasion potential were assessed using real-time qRT-PCR and invasion assay. Our results indicate that cells enriched via sphere formation expressed all the stemness-related genes and had an enhanced number of colonies, spheres and invaded cells compared to cells enriched using the CD133 cell surface marker. Moreover, miRNAs controlling metastasis increased in the melanospheres. This may be related to the involvement of CSCs in the metastatic process. However, this must be further confirmed through the application of knockdown experiments. The results show that sphere formation is a useful method for enriching melanoma stem cells. Melanospheres were found to upregulate miR-10b, 21, 200c, 373 and 520c, so we suggest that they may control both metastasis and stemness potential.