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The efficiency of cell reprogramming in two-dimensional (2D) cultures is limited. Given that cellular stemness is intimately related to microenvironmental changes, 3D cell cultures have the potential of overcoming this limited capacity by allowing cells to self-organize by aggregation. In 3D space, cells interact more efficiently, modify their cellular topology, gene expression, signaling, and metabolism. It is yet not clear as how 3D culture environments modify the reprogramming potential of fibroblasts. We demonstrate that 3D spheroids from dermal fibroblasts formed under ultra-low attachment conditions showed increased lactate production. This is a requisite for cell reprogramming, increase their expression of pluripotency genes, such as OCT4, NANOG and SOX2, and display upregulated cystathionine-β-synthase (CBS) and hydrogen sulfide (H2S) production. Knockdown of CBS by RNAi suppresses lactic acid and H2S production and concomitantly decreases the expression of OCT4 and NANOG. On the contrary, H2S donors, NaHS and garlic-derived diallyl trisulfide (DATS), promote the expression of OCT4, and support osteogenic trans-differentiation of fibroblasts. These results demonstrate that CBS mediated release of H2S regulates the reprogramming of dermal fibroblasts grown in 3D cultures and supports their trans-differentiation. [ABSTRACT FROM AUTHOR]

We recently demonstrated that cancer cells that recover from damage exhibit increased aerobic glycolysis, however, the molecular mechanism by which cancer cells survive the damage and show increased aerobic glycolysis remains unknown. Here, we demonstrate that diverse cancer cells that survive hypoxic or oxidative damage show rapid cell proliferation, and develop tolerance to damage associated with increased production of hydrogen sulfide (H2S) which drives up-regulation of nicotinamide phosphoribosyltransferase (Nampt). Consistent with existence of a H2S-Nampt energetic circuit, in damage recovered cancer cells, H2S, Nampt and ATP production exhibit a significant correlation. Moreover, the treatment of cancer cells with H2S donor, NaHS, coordinately increases Nampt and ATP levels, and protects cells from drug induced damage. Inhibition of cystathionine beta synthase (CBS) or cystathionase (CTH), enzymes which drive generation of H2S, decreases Nampt production while suppression of Nampt pathway by FK866, decreases H2S and ATP levels. Damage recovered cells isolated from tumors grown subcutaneously in athymic mice also show increased production of H2S, Nampt and ATP levels, associated with increased glycolysis and rapid proliferation. Together, these data show that upon recovery from potential lethal damage, H2S-Nampt directs energy expenditure and aerobic glycolysis in cancer cells, leads to their exponential growth, and causes a high degree of tolerance to damage. Identification of H2S-Nampt as a pathway responsible for induction of damage tolerance in cancer cells may underlie resistance to therapy and offers the opportunity to target this pathway as a means in treatment of cancer. [ABSTRACT FROM AUTHOR]

DUOXA1/NIP1, originally identified as a Numb-interacting protein, was recently shown to function as a maturation factor for the dual oxidase 1(DUOX1). In this study, we identified DUOXA1/NIP1 expression in breast cancer cells, observed high expression of DUOXA1 in non-invasive MCF7 cells and low expression in highly metastatic cells with impaired p53 functions linking the expression of DUOXA1 with p53. An inhibition of cell proliferation associated with upregulation of p21Cip1/WAF1 was observed in MDA-MB-231 cells following transfection of DUOXA1. The transient DUOXA1 overexpression also inhibited expression of cell-surface integrin αVβ5 and CD9, which is associated with impaired spreading ability. However, there was no difference in expression of these proteins in DUOX1-depleted cells. The observed effects coincided with an increase in reactive oxygen species (ROS) generation. Our data also demonstrate that DUOXA1 transient overexpression affected the cell–cell adhesion by modulating the actin cytoskeleton, and sensitized cells to doxorubicin. [ABSTRACT FROM AUTHOR]

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Abstract: Previous reports have shown that metallothionein (MT) may modulate p53 activity through zinc exchange. However, little is known on a direct interaction between MT and p53 in cells. The results demonstrate an interaction between MT and p53 can occur in vitro. The complex between MT and p53 was observed in breast cancer epithelial cells with both wild and inactive type of p53. Furthermore, it was shown that wt-p53 was preferentially associated with Apo-MT. Our data suggest that co-expression of MT and p53 and their complex formation in tumor cells may be involved in regulation of apoptosis in these cells. [Copyright &y& Elsevier]