Suppression of Ca2+ signaling enhances melanoma progression
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ABSTRACT: The role of store-operated Ca2+ entry (SOCE) in melanoma metastasis is highly controversial. To address this, we here examined UV-dependent metastasis, revealing a critical role for SOCE suppression in melanoma progression. UV-induced cholesterol biosynthesis was critical for UV-induced SOCE suppression and subsequent metastasis, although SOCE suppression alone was both necessary and sufficient for metastasis to occur. Further, SOCE suppression was responsible for UV-dependent differences in gene expression associated with both increased invasion and reduced glucose metabolism. Functional analyses further established that increased glucose uptake leads to a metabolic shift towards biosynthetic pathways critical for melanoma metastasis. Finally, examination of fresh surgically isolated human melanoma explants revealed cholesterol biosynthesis-dependent reduced SOCE. Invasiveness could be reversed with either cholesterol biosynthesis inhibitors or pharmacological SOCE potentiation. Collectively, we provide evidence that, contrary to current thinking, Ca2+ signals can block invasive behavior, and suppression of these signals promotes invasion and metastasis.
Project description:To investigate the effect of UV on SOCE suppression in melanoma progression We performed gene expression analysis of cells exhibiting SOCE suppression and cells not exhibiting SOCE suppression compared to control
Project description:The role of store-operated Ca2+ entry (SOCE) in melanoma metastasis is highly controversial. To address this, we here examined UV-dependent metastasis, revealing a critical role for SOCE suppression in melanoma progression. UV-induced cholesterol biosynthesis was critical for UV-induced SOCE suppression and subsequent metastasis, although SOCE suppression alone was both necessary and sufficient for metastasis to occur. Further, SOCE suppression was responsible for UV-dependent differences in gene expression associated with both increased invasion and reduced glucose metabolism. Functional analyses further established that increased glucose uptake leads to a metabolic shift towards biosynthetic pathways critical for melanoma metastasis. Finally, examination of fresh surgically isolated human melanoma explants revealed cholesterol biosynthesis-dependent reduced SOCE. Invasiveness could be reversed with either cholesterol biosynthesis inhibitors or pharmacological SOCE potentiation. Collectively, we provide evidence that, contrary to current thinking, Ca2+ signals can block invasive behavior, and suppression of these signals promotes invasion and metastasis.
Project description:Soft tissue sarcomas (STS) are a heterogeneous group of tumors associated with poor clinical outcome. While a subset of STS are characterized by simple karyotypes and recurrent chromosomal translocations, the mechanisms driving cytogenetically complex sarcomas are largely unknown. Clinical evidence led us to partially inactivate Pten and p53 in the smooth muscle lineage of mice, which developed high-grade undifferentiated pleomorphic sarcomas (HGUPS), leiomyosarcomas (LMS) and carcinosarcomas (CS) that widely recapitulate the human disease, including the aberrant karyotype and metastatic behavior. Pten was found haploinsufficient whereas the wild-type allele of p53 invariably gained point mutations. Gene expression profile showed upregulated Notch signaling in PtenM-bM-^HM-^F/+p53M-bM-^HM-^F/+ tumors compared to Pten+/+p53M-bM-^HM-^F/+. Consistently, Pten silencing exacerbated the clonogenic and invasive potential of p53-deficient bone marrow-derived mouse mesenchymal stem cells and tumor cells, while activating the Notch pathway. Moreover, the increased oncogenic behavior of PtenM-bM-^HM-^F/+p53M-bM-^HM-^F/+ and shPten-transduced Pten+/+p53M-bM-^HM-^F/+ tumor cells was counteracted by treatment with a gamma secretase inhibitor (GSI), suggesting that the aggressiveness of those tumors can be attributed, at least in part, to enhanced Notch signaling. This study demonstrates a cooperative role for Pten and p53 suppression in complex karyotype sarcomas while establishing Notch as an important functional player in the crosstalk of these pathways during tumor progression. Our results highlight the importance of molecularly subclassifying high-grade sarcoma patients for targeted treatments. Compare PtenM-bM-^HM-^F/+p53M-bM-^HM-^F/+ to Pten+/+p53M-bM-^HM-^F/+ high-grade undifferentiated pleomorphic sarcomas (HGUPS) 4 PtenM-bM-^HM-^F/+p53M-bM-^HM-^F/+ were compared to 5 Pten+/+p53M-bM-^HM-^F/+ Keywords: Differential gene expression.
Project description:Soft tissue sarcomas (STS) are a heterogeneous group of tumors associated with poor clinical outcome. While a subset of STS are characterized by simple karyotypes and recurrent chromosomal translocations, the mechanisms driving cytogenetically complex sarcomas are largely unknown. Clinical evidence led us to partially inactivate Pten and p53 in the smooth muscle lineage of mice, which developed high-grade undifferentiated pleomorphic sarcomas (HGUPS), leiomyosarcomas (LMS) and carcinosarcomas (CS) that widely recapitulate the human disease, including the aberrant karyotype and metastatic behavior. Pten was found haploinsufficient whereas the wild-type allele of p53 invariably gained point mutations. Gene expression profile showed upregulated Notch signaling in Pten∆/+p53∆/+ tumors compared to Pten+/+p53∆/+. Consistently, Pten silencing exacerbated the clonogenic and invasive potential of p53-deficient bone marrow-derived mouse mesenchymal stem cells and tumor cells, while activating the Notch pathway. Moreover, the increased oncogenic behavior of Pten∆/+p53∆/+ and shPten-transduced Pten+/+p53∆/+ tumor cells was counteracted by treatment with a gamma secretase inhibitor (GSI), suggesting that the aggressiveness of those tumors can be attributed, at least in part, to enhanced Notch signaling. This study demonstrates a cooperative role for Pten and p53 suppression in complex karyotype sarcomas while establishing Notch as an important functional player in the crosstalk of these pathways during tumor progression. Our results highlight the importance of molecularly subclassifying high-grade sarcoma patients for targeted treatments. Compare Pten∆/+p53∆/+ to Pten+/+p53∆/+ high-grade undifferentiated pleomorphic sarcomas (HGUPS)
Project description:Glutamate-triggered signal transduction is thought to contribute widely to cancer pathogenesis. In melanoma, overexpression of the metabotropic glutamate receptor (GRM)-1 occurs frequently and its ectopic expression in melanocytes is sufficient for neoplastic transformation. Clinical evaluation of the GRM1 signaling inhibitor riluzole in patients with advanced melanoma has demonstrated tumor regressions that are associated with a suppression of the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathways. Together, these results prompted us to investigate the downstream consequences of GRM1 signaling and its disruption in more detail. We found that melanoma cells with enhanced GRM1 expression generated larger tumors in vivo marked by more abundant blood vessels. Media conditioned by these cells in vitro contained relatively higher concentrations of interleukin-8 and VEGF due to GRM1-mediated activation of the AKT-mTOR-HIF1 pathway. In clinical specimens from patients receiving riluzole, we confirmed an inhibition of MAPK and PI3K/AKT activation in posttreatment as compared with pretreatment tumor specimens, which exhibited a decreased density of blood vessels. Together, our results demonstrate that GRM1 activation triggers proangiogenic signaling in melanoma, offering a mechanistic rationale to design treatment strategies for the most suitable combinatorial use of GRM1 inhibitors in patients.
Project description:Oncogene activation induces DNA damage responses and cell senescence. We report a key role of type I interferons (IFNs) in oncogene-induced senescence. IFN signaling-deficient melanocytes expressing activated Braf do not exhibit senescence and develop aggressive melanomas. Restoration of IFN signaling in IFN-deficient melanoma cells induces senescence and suppresses melanoma progression. Additional data from human melanoma patients and mouse transplanted tumor models suggest the importance of non-cell-autonomous IFN signaling. Inactivation of the IFN pathway is mediated by the IFN receptor IFNAR1 downregulation that invariably occurs during melanoma development. Mice harboring an IFNAR1 mutant, which is partially resistant to downregulation, delay melanoma development, suppress metastatic disease, and better respond to BRAF or PD-1 inhibitors. These results suggest that IFN signaling is an important tumor-suppressive pathway that inhibits melanoma development and progression and argue for targeting IFNAR1 downregulation to prevent metastatic disease and improve the efficacy of molecularly target and immune-targeted melanoma therapies.
Project description:The molecular mechanisms mediating cylindromatosis (CYLD) tumor suppressor function appear to be manifold. Here, we demonstrate that, in contrast to the increased levels of phosphorylated c-Jun NH(2)-terminal kinase (pJNK), CYLD was decreased in a majority of the melanoma cell lines and tissues examined. Exogenous expression of CYLD but not its catalytically deficient mutant markedly inhibited melanoma cell proliferation and migration in vitro and subcutaneous tumor growth in vivo. In addition, the melanoma cells expressing exogenous CYLD were unable to form pulmonary tumor nodules following tail-vein injection. At the molecular level, CYLD decreased ?1-integrin and inhibited pJNK induction by tumor necrosis factor-? or cell attachment to collagen IV. Moreover, CYLD induced an array of other molecular changes associated with modulation of the "malignant" phenotype, including a decreased expression of cyclin D1, N-cadherin, and nuclear Bcl3, and an increased expression of p53 and E-cadherin. Most interestingly, coexpression of the constitutively active MKK7 or c-Jun mutants with CYLD prevented the above molecular changes, and fully restored melanoma growth and metastatic potential in vivo. Our findings demonstrate that the JNK/activator protein 1 signaling pathway underlies the melanoma growth and metastasis that are associated with CYLD loss of function. Thus, restoration of CYLD and inhibition of JNK and ?1-integrin function represent potential therapeutic strategies for treatment of malignant melanoma.
Project description:Despite large cell-to-cell variations in the concentrations of individual signaling proteins, cells transmit signals correctly. This phenomenon raises the question of what signaling systems do to prevent a predicted high failure rate. Here we combine quantitative modeling, RNA interference, and targeted selective reaction monitoring (SRM) mass spectrometry, and we show for the ubiquitous and fundamental calcium signaling system that cells monitor cytosolic and endoplasmic reticulum (ER) Ca(2+) levels and adjust in parallel the concentrations of the store-operated Ca(2+) influx mediator stromal interaction molecule (STIM), the plasma membrane Ca(2+) pump plasma membrane Ca-ATPase (PMCA), and the ER Ca(2+) pump sarco/ER Ca(2+)-ATPase (SERCA). Model calculations show that this combined parallel regulation in protein expression levels effectively stabilizes basal cytosolic and ER Ca(2+) levels and preserves receptor signaling. Our results demonstrate that, rather than directly controlling the relative level of signaling proteins in a forward regulation strategy, cells prevent transmission failure by sensing the state of the signaling pathway and using multiple parallel adaptive feedbacks.
Project description:The overall survival remains undesirable in clinical glioma treatment. Inhibition of DNA-PKcs activity by its inhibitors suppresses tumor growth and enhances chemosensitivity of several tumors to chemotherapy. However, whether DNA-PKcs could be a potential target in glioma therapy remains unknown. In this study, we reported that the hyperactivated DNA-PKcs was profoundly correlated with glioma malignancy and observe a significant association between DNA-PKcs activation and survival of the glioma patients. Our data also found that inhibition of DNA-PKcs by its inhibitor KU0060648 sensitized glioma cells to TMZ in vitro. Specifically, we demonstrated that KU0060648 interrupted the formation of DNA-PKcs/AKT complex, leading to suppression of AKT signaling and resultantly enhanced TMZ efficacy. Combination of KU0060648 and TMZ substantially inhibited downstream effectors of AKT. The in vivo results were similar to those obtained in vitro. In conclusion, this study indicated that inhibition of DNA-PKcs activity could suppress glioma malignancies and increase TMZ efficacy, which was mainly through regulation of the of AKT signaling. Therefore, DNA-PKcs/AKT axis may be a promising target for improving current glioma therapy.