Epithelial Carcinoma Cell Proliferation Research Articles

LncRNA TONSL-AS1 regulates miR-490-3p/CDK1 to affect ovarian epithelial carcinoma cell proliferation

BackgroundLncRNA TONSL-AS1 has been characterized as a critical player in gastric cancer. By analyze the TCGA dataset, we observed the upregulation of TONSL-AS1 in ovarian epithelial carcinoma (EOC). We therefore investigated the involvement of TONSL-AS1 in EOC.MethodsThe differential expression of TONSL-AS1 in EOC was first explored by analyzing the TCGA dataset. The effects of overexpression of TONSL-AS1 and miR-490-3p on the expression of CDK1 mRNA and protein in OVCAR3 cells were evaluated by qPCR and western blot, respectively. CCK-8 assay was performed to investigate the effects of overexpression of TONSL-AS1, miR-490-3p and CDK1 on proliferation of OVCAR3 cells.ResultsWe observed that TONSL-AS1 was upregulated in EOC tumor tissues from EOC patients, and its high expression level was correlated with poor survival. Dual luciferase assay and RNA interaction prediction showed the direct interaction between TONSL-AS1 and miR-490-3p. However, overexpression of miR-490-3p did not affect the expression of TONSL-AS1. Instead, overexpression of TONSL-AS1 resulted in the upregulation of CDK1, a target of miR-490-3p, in EOC cells. Overexpression of TONSL-AS1 and CDK1 resulted in increased proliferation rate of EOC cells. Overexpression of miR-490-3p played an opposite role and reduced the effects of overexpression of TONSL -AS1 and CDK1.ConclusionsTherefore, TONSL-AS1 may regulate miR-490-3p/CDK1 to affect EOC cell proliferation.

Dipeptidyl peptidase 9 (DPP9) in human skin cells

BackgroundDipeptidyl peptidase 9 (DPP9) is a relatively new member of the DPPIV family of prolyl dipeptidases which is ubiquitously expressed. Its role in regulation of immune responses and proliferation of epithelial carcinoma cells was reported. There is no data on possible role of DPP9 expressed in skin epithelial cells (keratinocytes) and in dermal fibroblasts. Materials and methodsTranscriptional and protein expression of DPP9 and DPPIV was examined in fibroblasts and keratinocytes isolated from normal human skin. Localization of DPP9 and its sub-localization in Golgi were determined by immunocytochemistry staining. DPPIV-like enzyme activity was determined in cell lysates and in isolated cell fractions containing membranes (M), cytosol (C) and content of organelles/endosomes/vesicles (V). Relative contribution of DPPIV and DPP8/9 enzyme activity in these fractions was determined by using selective inhibitors: sitagliptin (selective for DPPIV) and 1G244 (selective for DPP9 and a highly homologous DPP8). Possible roles of DPP8/9 via its enzyme activity were analysed by assessment of survival and proliferative capacity of fibroblasts and HaCaT cells of keratinocyte origin in the presence of the inhibitors. Possible role of DPP9 in cell migration and/or adhesion was analysed in fibroblasts and HaCaT cells after DPP9 gene silencing. ResultsFibroblasts and keratinocytes exerted comparable level of DPP9 both at transcriptional and protein level. Fibroblasts strongly expressed DPPIV, whereas in keratinocytes DPPIV expression was low. DPP9 expression was found in cytosol and in perinuclear area of some fibroblasts, or in scattered pattern of keratinocytes, as well as in nuclei of some cells. Only low level of DPP9 sub-localization within Golgi was observed in fibroblasts and keratinocytes. DPPIV-like enzyme activity was about 5 times higher in lysates of fibroblasts than of HaCaT cells. In fibroblasts DPPIV-like enzyme activity was mainly (65%) found in the fraction containing cell membranes (M) and was predominantly (86.9%) due to DPPIV. In contrast, in HaCaT cells the DPPIV-like enzyme activity was mainly (84.2%) found in cytosol (C) and was predominantly (95.6%) due to DPP8/9. Survival and the proliferative capacity were significantly diminished in the presence of 10μM 1G244, both in fibroblasts and in HaCaT cells, suggesting possible role of DPP8/9 enzyme activity in regulation of survival and proliferation of these cells. DPP9 gene silencing resulted in decreased adhesion of fibroblasts, as well as in decreased migration of fibroblasts and HaCaT cells. Accumulation of DPP9 on the edges of plasma membranes of fibroblasts and keratinocytes adhering to surface supports the idea of possible role of DPP9 in cell adhesion. ConclusionsThis is the first study showing protein expression, sub-localization and possible biological roles of DPP9 expressed in isolated human skin cells. The data may be relevant for development of new drugs against skin diseases by targeting DPP9 expressed in the skin cells.

Loss of the desmosomal cadherin desmoglein-2 suppresses colon cancer cell proliferation through EGFR signaling

Desmosomal cadherins mediate cell-cell adhesion in epithelial tissues and have been known to be altered in cancer. We have previously shown that one of the two intestinal epithelial desmosomal cadherins, desmocollin-2 (Dsc2) loss promotes colonic epithelial carcinoma cell proliferation and tumor formation. In this study we show that loss of the other intestinal desmosomal cadherin, desmoglein-2 (Dsg2) that pairs with Dsc2, results in decreased epithelial cell proliferation and suppressed xenograft tumor growth in mice. Dsg2-deficient cells demonstrated a compensatory increase in Dsc2 expression, and small interfering RNA-mediated loss of Dsc2 restored proliferation in Dsg2-deficient cells. Dsg2 downregulation inhibited epidermal growth factor receptor (EGFR) signaling and cell proliferation through altered phosphorylation of EGFR and downstream extracellular signal-regulated kinase activation in parallel with inhibited EGFR receptor internalization. Additionally, we demonstrated a central role of Dsc2 in controlling EGFR signaling and cell proliferation in intestinal epithelial cells. Consistent with these findings, analyses of human colon cancers demonstrated increased Dsg2 protein expression. Taken together, these data demonstrate that partner desmosomal cadherins Dsg2 and Dsc2 play opposing roles in controlling colonic carcinoma cell proliferation through differential effects on EGFR signaling.

Ghrelin inhibits ovarian epithelial carcinoma cell proliferation in vitro

The only orexigenic peptide, ghrelin, which is primarily produced by the gastrointestinal tract, has been implicated in malignant cell proliferation and invasion. Ghrelin is a natural ligand of the growth hormone secretagogue receptor 1a (GHSR1a). However, the role of ghrelin in ovarian epithelial carcinoma remains unknown since the expression of GHSR1a in ovary is not confirmed. The aim of the present study was to assess expression of ghrelin and its receptor in human ovarian epithelial carcinoma and to examine the effect of ghrelin on carcinoma cell proliferation. Frozen sections of ovarian samples and the human ovarian epithelial carcinoma cell line, HO-8910, were used to characterize the expression of ghrelin/GHSR1a axis and the effect of ghrelin on proliferation. We found that ghrelin and GHSR1a are expressed in ovarian epithelial carcinoma in vivo and in vitro. Ghrelin inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest, and this inhibition may be abolished by the ghrelin receptor antagonist D-Lys-3-GH-releasing peptide-6 and ghrelin neutralizing antibody. Ghrelin enhances HO-8910 cell apoptosis and autophagy. The activation of mammalian target of rapamycin (mTOR) signaling pathway blocks the effects of ghrelin-induced autophagy and apoptosis, therefore reverses the inhibition of HO-8910 cell proliferation induced by ghrelin. In conclusion, the present study demonstrates that ghrelin inhibits the proliferation of human HO-8910 ovarian epithelial carcinoma cells by inducing apoptosis and autophagy via the mTOR signaling pathway. This study provides a novel regulatory signaling pathway of ghrelin-regulated ovarian epithelial carcinoma growth and may contribute to ovarian cancer prevention and therapy.

PTPN12 inhibits oral squamous epithelial carcinoma cell proliferation and invasion and can be used as a prognostic marker

Protein tyrosine phosphatase nonreceptor type 12 (PTPN12) has been recognized as a tumor suppressor gene that may inhibit tumor growth. However, PTPN12 expression in oral squamous carcinoma (OSCC) has not been studied. We showed reduced expression of PTPN12 in OSCC tissues. Decreased PTPN12 expression was significantly associated with clinical stage of the disease (P < 0.01). Moreover, reduction in PTPN12 correlated with the overactivation of STAT3. PTPRD negatively related to STAT3 phosphorylation (R = -0.535). Low expression of PTPN12 and high level of phosphorylation of STAT3 correlated with poor prognosis. Overexpression of PTPN12 inhibited proliferation and migration in OSCC cells. PTPN12 was associated with STAT3 and induced STAT3 dephosphorylation. Moreover, our results suggested that PTPN12 might function through binding and dephosphorylation of STAT3. Therefore, PTPN12 is a potential marker for prognosis of OSCC.

Mithramycin inhibits human epithelial carcinoma cell proliferation and migration involving downregulation of Eps8 expression

Mithramycin is an inhibitor of the binding of the Sp-family transcription factor to the GC box. Many studies show that mithramycin may reduce the expression of many oncogenes by inhibiting the mRNA and protein synthesis and it has been used as an antibiotic chemotherapy drug for a long time. Recently, Eps8 (EGFR pathway substrate 8) has been revealed to be a novel proto-oncogene related to cellular transformation, Rac activation and actin barbed-end-capping activity. Therefore, the aim of this study was to verify whether Eps8 might be regulated by mithramycin. Results showed that mithramycin could reduce the mRNA and protein levels of Eps8 in dose- and time-dependent manners in several cancer cell lines. Furthermore, cell growth and migration ability were also reduced significantly by mithramycin treatment. Since Src is a well-known Eps8 activity enhancer, a v-Src transfected IV5 cell line was subjected to mithramycin treatment and then analyzed to show that Src expression was unable to restore the mithramycin-induced decrease in Eps8 expression, cell growth, and migration ability. To further confirm the above mentioned results, the expression of Eps8 was eliminated by a transient transfection with siRNA and subsequent analysis showed that silencing of Eps8 might also lead to a reduced growth and migration ability of cancer cells. These findings suggested that Eps8 was involved in the regulation of growth and motility of cancer cells and mithramycin might exert its anticancer ability via a pathway involving the downregulation of Eps8.

P2X and P2Y purinergic receptors on human intestinal epithelial carcinoma cells: effects of extracellular nucleotides on apoptosis and cell proliferation

Extracellular nucleotides interact with purinergic receptors, which regulate ion transport in a variety of epithelia. With the use of two different human epithelial carcinoma cell lines (HCT8 and Caco-2), we have shown by RT-PCR that the cells express mRNA for P2X1, P2X3, P2X4, P2X5, P2X6, P2X7, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, and P2Y12 receptors. Protein expression for P2Y1 and P2Y2 receptors was also demonstrated immunohistochemically, and P2X receptor subtype protein was present in the following decreasing order: P2X4 > P2X7 > P2X1 > P2X3 > P2X6 > P2X5 >> P2X2. The functional presence of P2X7, P2Y1, P2Y2, and P2Y4 receptors was shown based on the effect of extracellular nucleotides on apoptosis or cell proliferation, and measurement of nucleotide-dependent calcium fluxes using a fluorometric imaging plate reader in the presence of different selective agonists and antagonists. ATP, at high concentrations, induced apoptosis through ligation of P2X7 and P2Y1 receptors; conversely, ATP, at lower concentrations, and UTP stimulated proliferation, probably acting via P2Y2 receptors. We therefore propose that stimulation or dysfunction of purinergic receptors may contribute at least partially to modulation of epithelial carcinoma cell proliferation and apoptosis.