Publications by authors named "Krishna C Vallabhaneni"

Mesenchymal stromal cells (hMSCs) have been used to understand the stromal cell properties in solid tumors because of their ablity to differentiate into most cell types. We investigated the role of EVs from hMSCs (hMSC-EVs) in breast cancer metastasis using MDA-MB-231 parental cell line and organotropic sub-lines. We demonstrated that hMSC-EVs significantly suppressed the metastatic potential of the parental cell line when compared to their organotropic sublines.

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It is well recognized that one of the major drawbacks of using traditional two dimensional cultures to model the living systems is inaccurately reflecting the physiological manner in which modulators, nutrients, oxygen, and metabolites are applied and removed. Moreover, the two dimensional culture system poorly reflects how different cell types interact with each other in the same microenvironment. Since the first global development of three dimensional (3D) cell culture techniques in the late 1960s, this last decade has seen an explosion of studies to promote 3D models in the fields of regenerative medicine and cancer.

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Studies have shown that mesenchymal stem/stromal cells (MSCs) from bone marrow are involved in the growth and metastasis of solid tumors but the mechanism remains unclear in osteosarcoma (OS). Previous studies have raised the possibility that OS cells may receive support from associated MSCs in the nutrient deprived core of the tumors through the release of supportive macromolecules and growth factors either in vesicular or non-vesicular forms. In the present study, we used stressed mesenchymal stem cells (SD-MSCs), control MSCs and OS cells to examine the hypothesis that tumor-associated MSCs in nutrient deprived core provide pro-proliferative, anti-apoptotic, and metastatic support to nearby tumor cells.

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Stem cells are proposed to continuously secrete trophic factors that potentially serve as mediators of autocrine and paracrine activities, associated with reprogramming of the tumor microenvironment, tissue regeneration, and repair. Hitherto, significant efforts have been made to understand the level of underlying paracrine activities influenced by stem cell secreted trophic factors, as little is known about these interactions. Recent findings, however, elucidate this role by reporting the effects of stem cell derived extracellular vesicles (EVs) that mimic the phenotypes of the cells from which they originate.

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Mesenchymal Stem/stromal cell (MSCs) transplantation procedures have been used since the 1960's to treat leukemia and other diseases, but due to the risks involved only patients with life threatening illnesses were typically subjected to the transplantation procedure until the last decade. Recent advancements in transplantation techniques have made it more feasible to use it for non-life-threatening diseases. However, the potential uses for stem cells are still limited by their rarity, and, in the case of allogeneic transplants, graft-vs.

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Mutant p53 (mtp53) is an oncogene that drives cancer cell proliferation. Here we report that mtp53 associates with the promoters of numerous nucleotide metabolism genes (NMG). Mtp53 knockdown reduces NMG expression and substantially depletes nucleotide pools, which attenuates GTP-dependent protein activity and cell invasion.

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Human mesenchymal stem/stromal cells (hMSCs) have been shown to support breast cancer cell proliferation and metastasis, partly through their secretome. hMSCs have a remarkable ability to survive for long periods under stress, and their secretome is tumor supportive. In this study, we have characterized the cargo of extracellular vesicular (EV) fraction (that is in the size range of 40-150nm) of serum deprived hMSCs (SD-MSCs).

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In recent years, the knowledge about the control of tumor microenvironment has increased and emerged as an important player in tumorigenesis. The role of normal stromal cells in the tumor initiation and progression has brought our vision in to the forefront of cell-to-cell communication. In this review, we focus on the mechanism of communication between stromal and tumor cells, which is based on the exchange of extracellular vesicles (EVs).

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Multipotent mesenchymal stem cells (MSCs) are promising candidates for regenerative cell-based therapy. The mechanisms underlying MSC differentiation and other functions relevant to therapeutic avenues remain however a matter of debate. Recent reports imply a critical role for intercellular contacts in MSC differentiation.

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Aims: Multipotent mesenchymal stem cells (MSCs) have regenerative properties and are recognized as putative players in the pathogenesis of cardiovascular diseases. The underlying molecular mechanisms remain, however, sparsely explored. Our study was designed to elucidate a probable role for the multifunctional urokinase (uPA)/urokinase receptor (uPAR) system in MSC regulation.

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