Functional interdependence of NHE1 and merlin in human melanoma cells

2014 ◽  
Vol 92 (6) ◽  
pp. 530-540 ◽  
Author(s):  
Fabian Frontzek ◽  
Svenja Nitzlaff ◽  
Malte Horstmann ◽  
Albrecht Schwab ◽  
Christian Stock
Keyword(s):  
Tumor Suppressor ◽  
Rho Gtpases ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Tumor Suppressor Function ◽  
Functional Link ◽  
Downstream Signaling ◽  
Nhe1 Activity ◽  
Cytosolic Acidification ◽  
Expression And Activity

Upregulation of the Na+/H+ exchanger isoform 1 (NHE1) has been correlated with tumor malignancy. In contrast, moesin-radixin-ezrin–like protein (merlin) is a tumor suppressor that protects from cancerogenesis. Merlin is highly related to the members of the ezrin, radixin, and moesin (ERM) protein family that are directly attached to and functionally linked with NHE1. In addition, merlin inhibits the MAPK cascade and the Rho-GTPases known to activate NHE1 activity. The present study investigates whether NHE1 expression and activity affect merlin or, conversely, whether merlin has an impact on NHE1 in human melanoma (MV3) cells. Indeed, features of merlin-deficient MV3 cells point to a functional link: merlin-deficient cells showed a decreased NHE1 expression and, paradoxically, an increase in NHE1 activity as measured upon cytosolic acidification (NH4Cl prepulse method). Loss of merlin also led to an elevated cell motility that could be further increased by NHE1 overexpression, whereas NHE1 overexpression alone had no effect on migration. In contrast, neither NHE1 expression nor its activity had an impact on merlin expression. These results suggest a novel tumor suppressor function of merlin in melanoma cells: the inhibition of the proto-oncogenic NHE1 activity, possibly including its downstream signaling pathways.

Effect of small inhibitors of nuclear export (SINE) on growth inhibition and apoptosis of human melanoma cells.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e13549-e13549
Author(s):  
Gregory B. Lesinski ◽  
Jennifer Yang ◽  
Matthew A Bill ◽  
Yosef Landesman ◽  
Sharon Shacham ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Cell Lines ◽  
Melanoma Cell ◽  
Nuclear Export ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Human Melanoma Cell ◽  
Nuclear Accumulation ◽  
Dependent Manner ◽  
Melanoma Cell Lines

e13549 Background: Inhibition of nuclear export can promote re-activation of tumor suppressor pathways. CRM1 (chromosomal regional maintenance 1) or XPO1 (exportin 1) is the major protein that mediates nuclear export. We hypothesized that CRM1 mediated nuclear export represents a novel therapeutic target that can be manipulated to inhibit melanoma cell survival. Methods: The growth inhibitory and pro-apoptotic effects of KPT-185, KPT-276 and KPT-330, small molecules selective inhibitor of nuclear export (SINE) were evaluated in human melanoma cell lines using an MTT assay and Annexin V/PI staining, respectively. Fluorescence microscopy and immunoblots were used to assess nuclear accumulation of tumor suppressor proteins. The trans-isomer of KPT-185 and DMSO (vehicle) were used as a negative controls in all assays. The pharmacokinetic (PK) profile of all compounds was evaluated in mice. Results: CRM1 protein was highly expressed in human melanoma cell lines with diverse molecular profiles (i.e., B-Raf, NRAS, p53). KPT-SINE inhibited melanoma cell growth in a concentration-dependent manner and induced apoptosis at nanomolar concentrations. Importantly, there was no evidence that B-Raf V600 mutational status influenced melanoma cell response to these agents. Nuclear accumulation and/or induction of p53, p21, FOXO3a, STAT1 and BAD, and reduction of MCL-1 occurred in melanoma cells at time points prior to apoptosis as shown by increase in cleaved PARP and caspase 3 levels. PK studies were conducted in mice following oral administration of 10 mg/kg, to guide drug selection for our ongoing efficacy studies in murine melanoma models. KPT-185 showed limited bioavailability and systemic exposure, while KPT-276 and KPT-330 showed >50% bioavailability reaching Cmax >5µM. Conclusions: This study represents the first report of CRM1 inhibition in melanoma. These data indicate that the novel SINE compounds can effectively inhibit CRM1-mediated nuclear export and induce apoptosis in melanoma cells. KPT-330 is currently under development as orally bioavailable, small molecule inhibitors for a human clinical trial.

scholarly journals Insulin-like growth factor binding protein 5 (IGFBP5) functions as a tumor suppressor in human melanoma cells

Oncotarget ◽  
2015 ◽  
Vol 6 (24) ◽  
pp. 20636-20649 ◽  
Author(s):  
Junyun Wang ◽  
Nan Ding ◽  
Yongjun Li ◽  
Hua Cheng ◽  
Dong Wang ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tumor Suppressor ◽  
Binding Protein ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Human Melanoma Cells

scholarly journals MicroRNA 211 Functions as a Metabolic Switch in Human Melanoma Cells

2016 ◽  
Vol 36 (7) ◽  
pp. 1090-1108 ◽  
Author(s):  
Joseph Mazar ◽  
Feng Qi ◽  
Bongyong Lee ◽  
John Marchica ◽  
Subramaniam Govindarajan ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Noncoding Rna ◽  
Ectopic Expression ◽  
The United States ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Pyruvate Dehydrogenase Kinase ◽  
Low Oxygen ◽  
Protein Loss ◽  
Metabolic Switch

MicroRNA 211 (miR-211) negatively regulates genes that drive invasion of metastatic melanoma. Compared to normal human melanocytes, miR-211 expression is significantly reduced or absent in nonpigmented melanoma cells and lost during human melanoma progression. To investigate the molecular mechanism of its tumor suppressor function, miR-211 was ectopically expressed in nonpigmented melanoma cells. Ectopic expression of miR-211 reduced hypoxia-inducible factor 1α (HIF-1α) protein levels and decreased cell growth during hypoxia. HIF-1α protein loss was correlated with the downregulation of a miR-211 target gene, pyruvate dehydrogenase kinase 4 (PDK4). We present evidence that resumption of miR-211-mediated downregulation ofPDK4in melanoma cells causes inhibition of invasion by nonpigmented melanomas via HIF-1α protein destabilization. Thus, the tumor suppressor miR-211 acts as a metabolic switch, and its loss is expected to promote cancer hallmarks in human melanomas. Melanoma, one of the deadliest forms of skin cancer, kills nearly 10,000 people in the United States per year. We had previously shown that a small noncoding RNA, termed miR-211, suppresses invasion and the growth of aggressive melanoma cells. The results presented here support the hypothesis that miR-211 loss in melanoma cells causes abnormal regulation of energy metabolism, which in turn allows cancer cells to survive under low oxygen concentrations—a condition that generally kills normal cells. These findings highlight a novel mechanism of melanoma formation: miR-211 is a molecular switch that is turned off in melanoma cells, raising the hope that in the future we might be able to turn the switch back on, thus providing a better treatment option for melanoma.

Abstract A06: MicroRNA-195 acts as a tumor suppressor miRNA in human melanoma cells by targeting Prohibitin 1

2018 ◽  
Author(s):  
Priscila D. R. Cirilo ◽  
Bruna R. S. Côrrea ◽  
Mei Qiao ◽  
Luciana N. S. Andrade ◽  
Roger Chammas ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Human Melanoma Cells ◽  
Prohibitin 1

Sequential detection of mRNA for the chemokine IL-8 and macrophages (F4/80) in human melanoma

1995 ◽  
Vol 53 ◽  
pp. 1008-1009
Author(s):  
C.D. Bucana ◽  
R. Sanchez ◽  
R. Singh ◽  
I.J. Fidler
Keyword(s):  
Tumor Cells ◽  
Nude Mice ◽  
Constitutive Expression ◽  
Metastatic Potential ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Angiogenic Factor ◽  
Infiltrating Cells ◽  
Immunoperoxidase Assay ◽  
Multifunctional Cytokine

The purpose of this study was to demonstrate by ISH the presence of IL-8 mRNA, and by immunohistochemistry (IHC) the presence of the chemokine IL-8 and the distribution of infiltrating macrophages in subcutaneous melanomas in the same tumor. IL-8 is a multifunctional cytokine produced by melanoma cells, activated macrophages and monocytes and it has been shown to be a growth and angiogenic factor for tumor cells. More recently it was shown that constitutive expression of IL-8 correlated directly with metastatic potential of human melanoma cells in nude mice. IL-8 content of a solid tumor as determined by Western blot analysis does not take into account the contribution of macrophages. Previous studies showed that murine tumors contain many infiltrating cells interspersed among tumor cells whereas human tumors growing in nude mice exhibit macrophages at the periphery or between tumor islands. In this study we demonstrate the expression of IL-8 and the distribution of macrophages by immunoperoxidase assay and IL-8 mRNA by ISH.

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