Carvacrol promotes angiogenic paracrine potential and endothelial differentiation of human mesenchymal stem cells at low concentrations.

OBJECTIVES: Phenolic monoterpene compound, named Carvacrol, has been found to exert different biological outcomes. It has been accepted that the angiogenic activity of human mesenchymal stem cells was crucial in the pursuit of appropriate regeneration. In the current experiment, we investigated the contribution of Carvacrol on the angiogenic behavior of primary human mesenchymal stem cells. METHODS: Mesenchymal stem cells were exposed to Carvacrol in a dose ranging from 25 to 200µM for 48h. We measured cell survival rate by MTT assay and migration rate by a scratch test. The oxidative status was monitored by measuring SOD, GPx activity. The endothelial differentiation was studied by evaluating the level of VE-cadherin and vWF by real-time PCR and ELISA analyses. The content of VEGF and tubulogenesis behavior was monitored in vitro. We also conducted Matrigel plug in vivo CAM assay to assess the angiogenic potential of conditioned media from human mesenchymal stem cells after exposure to Carvacrol. RESULTS: Carvacrol was able to increase mesenchymal stem cell survival and migration rate (p<0.05). An increased activity of SOD was obtained while GPx activity unchanged or reduced. We confirmed the endothelial differentiation of stem cells by detecting vWF and VE-cadherin expression (p<0.05). The VEGF expression was increased and mesenchymal stem cells conditioned media improved angiogenesis tube formation in vitro (p<0.05). Moreover, histological analysis revealed an enhanced microvascular density at the site of Matrigel plug in CAM assay. CONCLUSIONS: Our data shed lights on the possibility of a Carvacrol to induce angiogenesis in human mesenchymal stem cells by modulating cell differentiation and paracrine angiogenic response.

The impact of different extracellular matrices on melatonin effect in proliferation and stemness properties of ovarian cancer cells.

AIM: Endogenous melatonin has numerous physiological roles on modulating the function of different organs. Recent studies revealed oncostatic and protective effects of this molecule on tumor development. In this study, we examined the impact of melatonin and key underlying mechanisms on stemness, morphology, invasiveness and viability of SKOV3 ovarian cancer cells in different types of extracellular matrix. METHODS: Cell viability was evaluated by MTT Assay. Colony-forming assay was performed by seeding 4×103 cells on different matrices in six well-plate. The percentage of cancer stem like cells was determined by flow cytometric assay after applying antibodies against stemness markers, CD133 and CD44. Different types of extracellular matrix including fibronectin, gelatin, collagen and matrigel were applied to incubate the cells in the presence of melatonin. Downstream gene expressions including VEGF and E-cadherin were determined by Real-time PCR. RESULTS: Melatonin (0.1mM) decreased the percentage of viable cells up to 61.79±8.2% (p<0.05). Colony formation assay revealed the significant impact of melatonin in inhibition of colony formation in these cells. The maximum effect was shown in the cells incubated with melatonin on gelatin (p<0.05). Identification of stemness markers showed that applying matrigel caused significant increase in the percentage of cancer stem like cells compared to other types of extracellular matrix (p<0.05). However melatonin slightly diminished the number of stem cell like cells in all incubated matrices. Our results from gene expression assays revealed that melatonin induced a marked increase in E-cadherin along with decrease in VEGF expression levels (p<0.05). CONCLUSION: Our results suggest that interaction between ovarian cancer cells and neighboring matrices determines the subsequent anti invasive activities of melatonin.