A TTRAP adaptor molekula szerepének vizsgálata a TGF-beta ligand család szignalizációs mechanizmusában = Role of the TTRAP adaptor molecule in the signaling mechanisms of TGF-beta family ligands

A TGF-β fehérje egy esszenciális növekedési faktor, amely fontos szabályzó szerepet tölt be a sejtek életének szinte minden mozzanatában. Mindezek mellett kiemelkedő szereppel bír a daganatos betegségek elleni védelemben is, gátolva a szervezetben a sejtek kontrollálatlan burjánzását. Tumor fejlődés során a TGF-β jelátviteli útvonal komponenseiben mutációk és epigenetikai változások halmozódnak fel, amelyek nem csak a citokin sejtosztódást gátló hatásaival szembeni rezisztencia kialakulását eredményezik, hanem gyakran paradox módon azt a tumorok progresszióját elősegítő tényezővé változtatják. Kutatásaink során ennek a fontos biológiai jelenségnek a jobb megértését tűztük célul. Figyelmüket döntően egy új adaptor fehérjére, TTRAP-re összpontosítottuk. Megállapítottuk, hogy TTRAP fontos szerepet tölt be mind a Smad függő mind a Smad független TGF-β jelátviteli folyamatokban. Kifejlesztettünk egy egér emlő epiteliáls sejtvonalon (NMuMG) alapuló modell rendszert amelynek felhasználásával bizonyítottuk, hogy a molekula fontos komponense a TGF-β indukálta programozott sejthalál (apoptózis) folyamatának. Kutatásaink a rákellenes szerek egy olyan új osztályának a kifejlesztéséhez teremthetik meg az alapot, amelyek specifikusan gátolják TGF-β tumor fejlődést elősegítő hatásait előrehaladott rák betegségekben. | TGF-β is a pleiotropic cytokine that regulates mammalian development, differentiation, and homeostasis. It is also a potent anticancer agent that prohibits the uncontrolled proliferation of epithelial, endothelial, and hematopoietic cells. Aberrations in the TGF-β pathway bring about resistance to TGF-β-mediated growth arrest and thus give rise to human malignances. Paradoxically, these genetic and epigenetic aberrations also conspire to convert TGF-β from a suppressor of tumor formation to a promoter of their growth, survival and metastasis. Our main objective was to better understand the mechanisms that underlie the ability of TGF-β to mediate tumor suppression in normal cells, and conversely, to facilitate cancer progression in malignant cells. We focused our attention on elucidating the role of the TTRAP adaptor molecule in TGF-β signaling. We have shown that TTRAP is an important component of both Smad-dependent and Smad-independent branches of TGF-β signaling. In addition, we have developed a murine mammary epithelial cell line (NMuMG) based model system for studying TTRAP's role in various TGF-β dependent biological responses. Using this model, we have demonstrated that TTRAP is a critical component of TGF-β induced apoptosis. In summary, our results may open up new avenues for developing drugs capable of selectively negating TGF-β's pro-oncogenic effects in late stage malignances

Integrative Genomic Analyses of Patient-Matched Intracranial and Extracranial Metastases Reveal a Novel Brain-Specific Landscape of Genetic Variants in Driver Genes of Malignant Melanoma

Background: Development of brain metastases in advanced melanoma patients is a frequent event that limits patients’ quality of life and survival. Despite recent insights into melanoma genetics, systematic analyses of genetic alterations in melanoma brain metastasis formation are lacking. Moreover, whether brain metastases harbor distinct genetic alterations beyond those observed at different anatomic sites of the same patient remains unknown. Experimental Design and Results: In our study, 54 intracranial and 18 corresponding extracranial melanoma metastases were analyzed for mutations using targeted next generation sequencing of 29 recurrently mutated driver genes in melanoma. In 11 of 16 paired samples, we detected nucleotide modifications in brain metastases that were absent in matched metastases at extracranial sites. Moreover, we identified novel genetic variants in ARID1A, ARID2, SMARCA4 and BAP1, genes that have not been linked to brain metastases before; albeit most frequent mutations were found in ARID1A, ARID2 and BRAF. Conclusion: Our data provide new insights into the genetic landscape of intracranial melanoma metastases supporting a branched evolution model of metastasis formation

Increased mitochondrial function downstream from KDM5A histone demethylase rescues differentiation in pRB-deficient cells

The retinoblastoma tumor suppressor protein pRb restricts cell growth through inhibition of cell cycle progression. Increasing evidence suggests that pRb also promotes differentiation, but the mechanisms are poorly understood, and the key question remains as to how differentiation in tumor cells can be enhanced in order to diminish their aggressive potential. Previously, we identified the histone demethylase KDM5A (lysine [K]-specific demethylase 5A), which demethylates histone H3 on Lys4 (H3K4), as a pRB-interacting protein counteracting pRB's role in promoting differentiation. Here we show that loss of Kdm5a restores differentiation through increasing mitochondrial respiration. This metabolic effect is both necessary and sufficient to induce the expression of a network of cell type-specific signaling and structural genes. Importantly, the regulatory functions of pRB in the cell cycle and differentiation are distinct because although restoring differentiation requires intact mitochondrial function, it does not necessitate cell cycle exit. Cells lacking Rb1 exhibit defective mitochondria and decreased oxygen consumption. Kdm5a is a direct repressor of metabolic regulatory genes, thus explaining the compensatory role of Kdm5a deletion in restoring mitochondrial function and differentiation. Significantly, activation of mitochondrial function by the mitochondrial biogenesis regulator Pgc-1α (peroxisome proliferator-activated receptor γ-coactivator 1α; also called PPARGC1A) a coactivator of the Kdm5a target genes, is sufficient to override the differentiation block. Overexpression of Pgc-1α, like KDM5A deletion, inhibits cell growth in RB-negative human cancer cell lines. The rescue of differentiation by loss of KDM5A or by activation of mitochondrial biogenesis reveals the switch to oxidative phosphorylation as an essential step in restoring differentiation and a less aggressive cancer phenotype.This work was supported by R01CA138631 (to E.V.B.) and R01GM094220 (to J.R.) from the National Institutes of Health, educational grant SAF2009-06954 (to N.L.-B.) from the Spanish Ministry of Science, and a fellowship from the Agencia de Gestió d'Ajuts Universitaris i de Recerca of the Catalonian Government, Spain (to A.B.M.M.K.I.

Increased mitochondrial function downstream from KDM5A histone demethylase rescues differentiation in pRB-deficient cells

The retinoblastoma tumor suppressor protein pRb restricts cell growth through inhibition of cell cycle progression. Increasing evidence suggests that pRb also promotes differentiation, but the mechanisms are poorly understood, and the key question remains as to how differentiation in tumor cells can be enhanced in order to diminish their aggressive potential. Previously, we identified the histone demethylase KDM5A (lysine [K]-specific demethylase 5A), which demethylates histone H3 on Lys4 (H3K4), as a pRB-interacting protein counteracting pRB's role in promoting differentiation. Here we show that loss of Kdm5a restores differentiation through increasing mitochondrial respiration. This metabolic effect is both necessary and sufficient to induce the expression of a network of cell type-specific signaling and structural genes. Importantly, the regulatory functions of pRB in the cell cycle and differentiation are distinct because although restoring differentiation requires intact mitochondrial function, it does not necessitate cell cycle exit. Cells lacking Rb1 exhibit defective mitochondria and decreased oxygen consumption. Kdm5a is a direct repressor of metabolic regulatory genes, thus explaining the compensatory role of Kdm5a deletion in restoring mitochondrial function and differentiation. Significantly, activation of mitochondrial function by the mitochondrial biogenesis regulator Pgc-1α (peroxisome proliferator-activated receptor γ-coactivator 1α; also called PPARGC1A) a coactivator of the Kdm5a target genes, is sufficient to override the differentiation block. Overexpression of Pgc-1α, like KDM5A deletion, inhibits cell growth in RB-negative human cancer cell lines. The rescue of differentiation by loss of KDM5A or by activation of mitochondrial biogenesis reveals the switch to oxidative phosphorylation as an essential step in restoring differentiation and a less aggressive cancer phenotype.This work was supported by R01CA138631 (to E.V.B.) and R01GM094220 (to J.R.) from the National Institutes of Health, educational grant SAF2009-06954 (to N.L.-B.) from the Spanish Ministry of Science, and a fellowship from the Agencia de Gestió d'Ajuts Universitaris i de Recerca of the Catalonian Government, Spain (to A.B.M.M.K.I.

Integrative Genomic Analyses of Patient-Matched Intracranial and Extracranial Metastases Reveal a Novel Brain-Specific Landscape of Genetic Variants in Driver Genes of Malignant Melanoma

Background: Development of brain metastases in advanced melanoma patients is a frequent event that limits patients’ quality of life and survival. Despite recent insights into melanoma genetics, systematic analyses of genetic alterations in melanoma brain metastasis formation are lacking. Moreover, whether brain metastases harbor distinct genetic alterations beyond those observed at different anatomic sites of the same patient remains unknown. Experimental Design and Results: In our study, 54 intracranial and 18 corresponding extracranial melanoma metastases were analyzed for mutations using targeted next generation sequencing of 29 recurrently mutated driver genes in melanoma. In 11 of 16 paired samples, we detected nucleotide modifications in brain metastases that were absent in matched metastases at extracranial sites. Moreover, we identified novel genetic variants in ARID1A, ARID2, SMARCA4 and BAP1, genes that have not been linked to brain metastases before; albeit most frequent mutations were found in ARID1A, ARID2 and BRAF. Conclusion: Our data provide new insights into the genetic landscape of intracranial melanoma metastases supporting a branched evolution model of metastasis formation

Integrative Genomic Analyses of Patient-Matched Intracranial and Extracranial Metastases Reveal a Novel Brain-Specific Landscape of Genetic Variants in Driver Genes of Malignant Melanoma

Background: Development of brain metastases in advanced melanoma patients is a frequent event that limits patients’ quality of life and survival. Despite recent insights into melanoma genetics, systematic analyses of genetic alterations in melanoma brain metastasis formation are lacking. Moreover, whether brain metastases harbor distinct genetic alterations beyond those observed at different anatomic sites of the same patient remains unknown. Experimental Design and Results: In our study, 54 intracranial and 18 corresponding extracranial melanoma metastases were analyzed for mutations using targeted next generation sequencing of 29 recurrently mutated driver genes in melanoma. In 11 of 16 paired samples, we detected nucleotide modifications in brain metastases that were absent in matched metastases at extracranial sites. Moreover, we identified novel genetic variants in ARID1A, ARID2, SMARCA4 and BAP1, genes that have not been linked to brain metastases before; albeit most frequent mutations were found in ARID1A, ARID2 and BRAF. Conclusion: Our data provide new insights into the genetic landscape of intracranial melanoma metastases supporting a branched evolution model of metastasis formation

Integrative Genomic Analyses of Patient-Matched Intracranial and Extracranial Metastases Reveal a Novel Brain-Specific Landscape of Genetic Variants in Driver Genes of Malignant Melanoma

Background: Development of brain metastases in advanced melanoma patients is a frequent event that limits patients’ quality of life and survival. Despite recent insights into melanoma genetics, systematic analyses of genetic alterations in melanoma brain metastasis formation are lacking. Moreover, whether brain metastases harbor distinct genetic alterations beyond those observed at different anatomic sites of the same patient remains unknown. Experimental Design and Results: In our study, 54 intracranial and 18 corresponding extracranial melanoma metastases were analyzed for mutations using targeted next generation sequencing of 29 recurrently mutated driver genes in melanoma. In 11 of 16 paired samples, we detected nucleotide modifications in brain metastases that were absent in matched metastases at extracranial sites. Moreover, we identified novel genetic variants in ARID1A, ARID2, SMARCA4 and BAP1, genes that have not been linked to brain metastases before; albeit most frequent mutations were found in ARID1A, ARID2 and BRAF. Conclusion: Our data provide new insights into the genetic landscape of intracranial melanoma metastases supporting a branched evolution model of metastasis formation

The Prognostic Relevance of PMCA4 Expression in Melanoma : Gender Specificity and Implications for Immune Checkpoint Inhibition

PMCA4 is a critical regulator of Ca2+ homeostasis in mammalian cells. While its biological and prognostic relevance in several cancer types has already been demonstrated, only preclinical investigations suggested a metastasis suppressor function in melanoma. Therefore, we studied the expression pattern of PMCA4 in human skin, nevus, as well as in primary and metastatic melanoma using immunohistochemistry. Furthermore, we analyzed the prognostic power of PMCA4 mRNA levels in cutaneous melanoma both at the non-metastatic stage as well as after PD-1 blockade in advanced disease. PMCA4 localizes to the plasma membrane in a differentiation dependent manner in human skin and mucosa, while nevus cells showed no plasma membrane staining. In contrast, primary cutaneous, choroidal and conjunctival melanoma cells showed specific plasma membrane localization of PMCA4 with a wide range of intensities. Analyzing the TCGA cohort, PMCA4 mRNA levels showed a gender specific prognostic impact in stage I–III melanoma. Female patients with high transcript levels had a significantly longer progression-free survival. Melanoma cell specific PMCA4 protein expression is associated with anaplasticity in melanoma lung metastasis but had no impact on survival after lung metastasectomy. Importantly, high PMCA4 transcript levels derived from RNA-seq of cutaneous melanoma are associated with significantly longer overall survival after PD-1 blockade. In summary, we demonstrated that human melanoma cells express PMCA4 and PMCA4 transcript levels carry prognostic information in a gender specific manner