Rho/MRTF-A-Induced Integrin Expression Regulates Angiogenesis in Differentiated Multipotent Mesenchymal Stem Cells

MiR-17-5p and MKL-1 modulate stem cell characteristics of gastric cancer cells

Effectively targeting cancer stem cells to treat cancer has great therapeutic prospects. However, the effect of microRNA miR-17/MKL-1 on gastric cancer stem cells has not been studied yet. This study preliminarily explored the mechanism of miR-17/MKL-1 in gastric cancer stem cells. Many previous reports have indicated that microRNA and EMT regulated cancer stem cell characteristics, and miR-17 and MKL-1 were involved as a critical gene in migration and invasion in the EMT pathway. Through RT-PCR, Western Blot, flow cytometry, immunofluorescence, sphere formation xenograft tumor assays and drug resistance, the role of miR-17-5p and MKL-1 on promoting stem cell-like properties of gastric cancer were verified in vivo and vitro. Next, MKL-1 targets CD44, EpCAM, and miR -17-5p promoter verified by luciferase assay and ChIP. Besides, the TCGA database analysis found that both miR-17-5p and MKL-1 increased in gastric cancer, and the prognostic survival of the MKL-1 high expression group was reduced. It is found that MKL-1 promotes expression by targeting miR-17, CD44 and EpCAM promoters. Besides, the TCGA database analysis found that both miR-17-5p and MKL-1 increased in gastric cancer, and the prognostic survival of the MKL-1 high expression group was reduced. These findings reveal new regulatory signaling pathways for gastric cancer stem cells, thus it give new insights on potential early diagnosis and/or molecular therapy for gastric cancer.

TWIST1-Reprogrammed Endothelial Cell Transplantation Potentiates Neovascularization-Mediated Diabetic Wound Tissue Regeneration

Hypovascularized diabetic nonhealing wounds are due to reduced number and impaired physiology of endogenous endothelial progenitor cell (EPC) population that limits their recruitment and mobilization at the wound site. For enrichment of the EPC repertoire from nonendothelial precursors, abundantly available mesenchymal stromal cells (MSC) were reprogrammed into induced endothelial cells (iEC). We identified cell signaling molecular targets by meta-analysis of microarray data sets. BMP-2 induction leads to the expression of inhibitory Smad 6/7-dependent negative transcriptional regulation of ID1, rendering the latter's reduced binding to TWIST1 during transdifferentiation of Wharton jelly-derived MSC (WJ-MSC) into iEC. TWIST1, in turn, regulates endothelial gene transcription, positively of proangiogenic KDR and negatively, in part, of antiangiogenic SFRP4 Twist1 reprogramming enhanced the endothelial lineage commitment of WJ-MSC and increased the vasculogenic potential of reprogrammed endothelial cells (rEC). Transplantation of stable TWIST1 rEC into a type 1 and 2 diabetic full-thickness splinted wound healing murine model enhanced the microcirculatory blood flow and accelerated the wound tissue regeneration. An increased or decreased colocalization of GFP with KDR/SFRP4 and CD31 in the regenerated diabetic wound bed with TWIST1 overexpression or silencing (piLenti-TWIST1-shRNA-GFP), respectively, further confirmed improved neovascularization. This study depicted the reprogramming of WJ-MSC into rEC using unique transcription factor TWIST1 for an efficacious cell transplantation therapy to induce neovascularization-mediated diabetic wound tissue regeneration.

Endothelial progenitor cell therapy for chronic wound tissue regeneration

Despite advancements in wound care, healing of chronic diabetic wounds remains a great challenge for the clinical fraternity because of the intricacies of the healing process. Due to the limitations of existing treatment strategies for chronic wounds, stem/progenitor cell transplantation therapies have been explored as an alternative for tissue regeneration at the wound site. The non-healing phenotype of chronic wounds is directly associated with lack of vascularization. Therefore, endothelial progenitor cell (EPC) transplantation is proving to be a promising approach for the treatment of hypo-vascular chronic wounds. With the existing knowledge in EPC biology, significant efforts have been made to enrich EPCs at the chronic wound site, generating EPCs from somatic cells, induced pluripotent stem cells (iPSCs) using transcription factors, or from adult stem cells using chemicals/drugs for use in transplantation, as well as modulating the endogenous dysfunctional/compromised EPCs under diabetic conditions. This review mainly focuses on the pre-clinical and clinical approaches undertaken to date with EPC-based translational therapy for chronic diabetic as well as non-diabetic wounds to evaluate their vascularity-mediated regeneration potential.

Rho-Associated Coiled-Coil Kinase (ROCK) in Molecular Regulation of Angiogenesis

Identified as a major downstream effector of the small GTPase RhoA, Rho-associated coiled-coil kinase (ROCK) is a versatile regulator of multiple cellular processes. Angiogenesis, the process of generating new capillaries from the pre-existing ones, is required for the development of various diseases such as cancer, diabetes and rheumatoid arthritis. Recently, ROCK has attracted attention for its crucial role in angiogenesis, making it a promising target for new therapeutic approaches. In this review, we summarize recent advances in understanding the role of ROCK signaling in regulating the permeability, migration, proliferation and tubulogenesis of endothelial cells (ECs), as well as its functions in non-ECs which constitute the pro-angiogenic microenvironment. The therapeutic potential of ROCK inhibitors in angiogenesis-related diseases is also discussed.

Pharmacological intervention of MKL/SRF signaling by CCG-1423 impedes endothelial cell migration and angiogenesis

De novo synthesis of cytoskeleton-regulatory proteins triggered by the megakaryoblastic leukemia (MKL)/serum response factor (SRF) transcriptional system in response to pro-angiogenic growth factors lies at the heart of endothelial cell (EC) migration (a critical element of angiogenesis) and neovascularization. This study explores whether pharmacological intervention of MKL/SRF signaling axis by CCG-1423 is able to suppress angiogenesis. Our studies show that CCG-1423 inhibits migration and cord morphogenesis of EC in vitro and sprouting angiogenesis ex vivo and in vivo, suggesting CCG-1423 could be a novel anti-angiogenic agent. Kymography analyses of membrane dynamics of EC revealed that CCG-1423 treatment causes a major defect in membrane protrusion. CCG-1423 treatment led to attenuated expression of several actin-binding proteins that are important for driving membrane protrusion including ArpC2, VASP, and profilin1 (Pfn1) with the most drastic effect seen on the expression of Pfn1. Finally, depletion of Pfn1 alone is also sufficient for a dramatic decrease in sprouting angiogenesis of EC in vitro and ex vivo, further suggesting that Pfn1 depletion may be one of the mechanisms of the anti-angiogenic action of CCG-1423.

Derivate Isocorydine (d-ICD) Suppresses Migration and Invasion of Hepatocellular Carcinoma Cell by Downregulating ITGA1 Expression

In our previous studies, we found that isocorydine (ICD) could be a potential antitumor agent in hepatocellular carcinoma (HCC). Derivate isocorydine (d-ICD), a more effective antitumor agent, has been demonstrated to inhibit proliferation and drug resistance in HCC. In order to investigate the potential role of d-ICD on HCC cell migration and its possible mechanism, wound healing assay, trans-well invasion assay, western blot analysis, and qRT-PCR were performed to study the migration and invasion ability of HCC cells as well as relevant molecular alteration following d-ICD treatment. Results indicated that the migration and invasion ability of HCC cells were suppressed when cultured with d-ICD. Meanwhile, the expression level of ITGA1 was markedly reduced. Furthermore, we found that ITGA1 promotes HCC cell migration and invasion in vitro, and that ITGA1 can partly reverse the effect of d-ICD-induced migration and invasion suppression in HCC cells. In addition, dual luciferase reporter assay and chromatin immunoprecipitation assay were used to study the expression regulation of ITGA1, and found that E2F1 directly upregulates ITGA1 expression and d-ICD inhibits E2F1 expression. Taken together, these results reveal that d-ICD inhibits HCC cell migration and invasion may partly by downregulating E2F1/ITGA1 expression.

Sphingosine 1-phosphate elicits RhoA-dependent proliferation and MRTF-A mediated gene induction in CPCs

Although c-kit(+) cardiac progenitor cells (CPCs) are currently used in clinical trials there remain considerable gaps in our understanding of the molecular mechanisms underlying their proliferation and differentiation. G-protein coupled receptors (GPCRs) play an important role in regulating these processes in mammalian cell types thus we assessed GPCR mRNA expression in c-kit(+) cells isolated from adult mouse hearts. Our data provide the first comprehensive overview of the distribution of this fundamental class of cardiac receptors in CPCs and reveal notable distinctions from that of adult cardiomyocytes. We focused on GPCRs that couple to RhoA activation in particular those for sphingosine-1-phosphate (S1P). The S1P2 and S1P3 receptors are the most abundant S1P receptor subtypes in mouse and human CPCs while cardiomyocytes express predominantly S1P1 receptors. Treatment of CPCs with S1P, as with thrombin and serum, increased proliferation through a pathway requiring RhoA signaling, as evidenced by significant attenuation when Rho was inhibited by treatment with C3 toxin. Further analysis demonstrated that both S1P- and serum-induced proliferation are regulated through the S1P2 and S1P3 receptor subtypes which couple to Gα12/13 to elicit RhoA activation. The transcriptional co-activator MRTF-A was activated by S1P as assessed by its nuclear accumulation and induction of a RhoA/MRTF-A luciferase reporter. In addition S1P treatment increased expression of cardiac lineage markers Mef2C and GATA4 and the smooth muscle marker GATA6 through activation of MRTF-A. In conclusion, we delineate an S1P-regulated signaling pathway in CPCs that introduces the possibility of targeting S1P2/3 receptors, Gα12/13 or RhoA to influence the proliferation and commitment of c-kit(+) CPCs and improve the response of the myocardium following injury.