Timp1 Promotes Cell Survival by Activating the PDK1 Signaling Pathway in Melanoma

High TIMP1 expression is associated with poor prognosis in melanoma, where it can bind to CD63 and beta 1 integrin, inducing PI3-kinase pathway and cell survival. Phosphatidylinositol (3,4,5)-trisphosphate (PIP3), generated under phosphatidylinositol-3-kinase (PI3K) activation, enables the recruitment and activation of protein kinase B (PKB/AKT) and phosphoinositide-dependent kinase 1 (PDK1) at the membrane, resulting in the phosphorylation of a host of other proteins. Using a melanoma progression model, we evaluated the impact of Timp1 and AKT silencing, as well as PI3K, PDK1, and protein kinase C (PKC) inhibitors on aggressiveness characteristics. Timp1 downregulation resulted in decreased anoikis resistance, clonogenicity, dacarbazine resistance, and in vivo tumor growth and lung colonization. In metastatic cells, pAKT(Thr308) is highly expressed, contributing to anoikis resistance. We showed that PDK1(Ser241) and PKC beta IISer660 are activated by Timp1 in different stages of melanoma progression, contributing to colony formation and anoikis resistance. Moreover, simultaneous inhibition of Timp1 and AKT in metastatic cells resulted in more effective anoikis inhibition. Our findings demonstrate that Timp1 promotes cell survival with the participation of PDK1 and PKC in melanoma. In addition, Timp1 and AKT act synergistically to confer anoikis resistance in advanced tumor stages. This study brings new insights about the mechanisms by which Timp1 promotes cell survival in melanoma, and points to novel perspectives for therapeutic approaches.Fundacao de Amparo a Pesquisa do Estado de Sao PauloConselho Nacional de Desenvolvimento Cientifico e TecnologicoUniv Fed Sao Paulo, Dept Pharmacol, BR-04039032 Sao Paulo, BrazilUniv Sao Paulo, Sch Med, Canc Inst Sao Paulo, Ctr Translat Invest Oncol LIM 24, BR-01246000 Sao Paulo, BrazilFac Med Santa Casa Sao Paulo, BR-01221020 Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Pharmacol, BR-04039032 Sao Paulo, Brazil|FAPESP: 2010/18715-8FAPESP: 2011/12306-1FAPESP: 2014/13663-0CNPq: 470681/2012-8Web of Scienc

Immediate increase in isotopic enrichment in small mammals following the expansion of a great cormorant colony

Colonies of great cormorants (Phalacrocorax carbo) impact terrestrial ecosystems through the transport of nutrients from aquatic to terrestrial ecosystems. Deposited guano overload the ecosystem with N and P, change soil pH and damage vegetation. The ways in which small mammals are impacted, however, are little known. We aimed to evaluate the effects of an expanding great cormorant colony, testing if the expansion immediately increased the input of biogens into the forest ecosystem and, further, if the growing influence of the colony was reflected in basal resources (plants and invertebrates) and the hair of small mammals. δ15N and δ13C signatures were analyzed in granivorous yellow-necked mice (Apodemus flavicollis), omnivorous bank voles (Myodes glareolus) and basal resources of animal and plant origin from the territory of a colony of great cormorants situated near the Baltic Sea in west Lithuania. We found that biogens transferred by great cormorants to the terrestrial ecosystem affected the potential foods of the small mammals and led to highly elevated and variable δ15N values. An increase of the size of the colony in 2015 resulted in isotopic enrichment of the small mammals in the zone of expansion in comparison to levels in 2014. The increase of δ15N in A. flavicollis was 7.5 % (p < 0.05) in the ecotone and 5.7 % in the expansion zone. The decrease in δ13C signatures in A. flavicollis was 4.5 % (p < 0.1) in the expansion zone and 3.1 % (p < 0.001) in the colony. In M. glareolus, the decrease in δ13C signatures was 8.5 % in the expansion zone, 3.3 % (p < 0.1) in the control zone and 2.6 % in the ecotone. Isotopic niches (central ellipses) of A. flavicollis in the colony and between the control and expansion zones were separated in 2014 and 2015, while they partially overlapped in the ecotone. The isotopic niches of M. glareolus in 2014 and 2015 were separated in the ecotone and had a small overlap in the colony. For most of the resources tested, the isotopic signatures in the established colony area were significantly higher than in the rest of cormorant-inhabited area. In the colony, the δ15N values in plants (16.9 ± 1.1 ‰) were higher than in invertebrates (13.6 ± 0.4 ‰). In the ecotone, the δ15N values were 12.0 ± 1.4 in plants and 14.7 ± 0.04 ‰ in invertebrates, while in the expansion zone they were 7.2 ± 3.0 and 9.9 ± 3.8 ‰, respectively. δ15N-rich resources led to increased δ15N values in the hair of A. flavicollis and M. glareolus. Thus, biogens from the great cormorant colony immediately affected small mammals through their food sources

SIRT1 regulates Mxd1 during malignant melanoma progression

In a murine melanoma model, malignant transformation promoted by a sustained stress condition was causally related to increased levels of reactive oxygen species resulting in DNA damage and massive epigenetic alterations. Since the chromatin modifier Sirtuin-1 (SIRT1) is a protein attracted to double-stranded DNA break (DSB) sites and can recruit other components of the epigenetic machinery, we aimed to define the role of SIRT1 in melanomagenesis through our melanoma model. The DNA damage marker, gamma H2AX was found increased in melanocytes after 24 hours of deadhesion, accompanied by increased SIRT1 expression and decreased levels of its target, H4K16ac. Moreover, SIRT1 started to be associated to DNMT3B during the stress condition, and this complex was maintained along malignant progression. Mxd1 was identified by ChIP-seq among the DNA sequences differentially associated with SIRT1 during deadhesion and was shown to be a common target of both, SIRT1 and DNMT3B. In addition, Mxd1 was found downregulated from pre-malignant melanocytes to metastatic melanoma cells. Treatment with DNMT inhibitor 5AzaCdR reversed the Mxd1 expression. Sirt1 stable silencing increased Mxd1 mRNA expression and led to down-regulation of MYC targets, such as Cdkn1a, Bcl2 and Psen2, whose upregulation is associated with human melanoma aggressiveness and poor prognosis. We demonstrated a novel role of the stress responsive protein SIRT1 in malignant transformation of melanocytes associated with deadhesion. Mxd1 was identified as a new SIRT1 target gene. SIRT1 promoted Mxd1 silencing, which led to increased activity of MYC oncogene contributing to melanoma progression.FAPESP [2011/0166-38, 2011/12306-1, 2014/13663-0, 2015/07925-5, 2016/06488-3]DAAD [PKZ A/12/79134]FAPESP/BAYLAT [2012/51300-7]Univ Fed Sao Paulo UNIFESP, Dept Pharmacol, Ontogeny & Epigenet Lab, Sao Paulo, SP, BrazilUniv Sao Paulo, Ribeirao Preto Med Sch, Dept Genet, Ribeirao Preto, SP, BrazilFriedrich Alexander Univ Erlangen Nurnberg FAU, Inst Pathol, Expt Tumorpathol, Erlangen, GermanyFriedrich Alexander Univ Erlangen Nurnberg FAU, Dept Pediat & Adolescent Med, Erlangen, GermanyUniv Fed Sao Paulo UNIFESP, Dept Pharmacol, Ontogeny & Epigenet Lab, Sao Paulo, SP, BrazilFAPESP [2011/0166-38, 2011/12306-1, 2014/13663-0, 2015/07925-5, 2016/06488-3]DAAD [PKZ A/12/79134]FAPESP/BAYLAT [2012/51300-7]Web of Scienc

Morte súbita e angina vasoespástica

Variant angina is defined by chest pain occurring at rest associated with transitory ST segment elevation on ECG, and is caused by a spasm of a coronary artery. Frequently, variant angina is associated with atherosclerotic coronary obstruction and patients with normal coronary arteries are rare. Patients with variant angina and normal coronary arteries have good prognosis, and the development of ventricular arrhythmias or sudden death is rare. The authors present two cases of sudden cardiac death in patients with variant angina and normal coronary arteries

Timp1 interacts with beta-1 integrin and CD63 along melanoma genesis and confers anoikis resistance by activating PI3-K signaling pathway independently of Akt phosphorylation

Background: Anoikis resistance is one of the abilities acquired along tumor progression. This characteristic is associated with metastasis development, since tumorigenic cells must survive independently of cell-matrix interactions in this process. in our laboratory, it was developed a murine melanocyte malignant transformation model associated with a sustained stressful condition. After subjecting melan-a melanocytes to 1, 2, 3 and 4 cycles of anchorage impediment, anoikis resistant cells were established and named 1C, 2C, 3C and 4C, respectively. These cells showed altered morphology and PMA independent cell growth, but were not tumorigenic, corresponding to pre-malignant cells. After limiting dilution of 4C pre-malignant cells, melanoma cell lines with different characteristics were obtained. Previous data from our group showed that increased Timp1 expression correlated with anoikis-resistant phenotype. Timp1 was shown to confer anchorage-independent growth capability to melan-a melanocytes and render melanoma cells more aggressive when injected into mice. However, the mechanisms involved in anoikis regulation by Timp1 in tumorigenic cells are not clear yet.Methods: the beta 1-integrin and Timp1 expression were evaluated by Western blotting and CD63 protein expression by flow cytometry using specific antibodies. To analyze the interaction among Timp1, CD63 and beta 1-integrin, immunoprecipitation assays were performed, anoikis resistance capability was evaluated in the presence or not of the PI3-K inhibitors, Wortmannin and LY294002. Relative expression of TIMP1 and CD63 in human metastatic melanoma cells was analyzed by real time PCR.Results: Differential association among Timp1, CD63 and beta 1-integrins was observed in melan-a melanocytes, 4C pre-malignant melanocytes and 4C11- and 4C11+ melanoma cells. Timp1 present in conditioned medium of melanoma cells rendered melan-a melanocytes anoikis-resistant through PI3-K signaling pathway independently of Akt activation. in human melanoma cell lines, in which TIMP1 and beta-1 integrin were also found to be interacting, TIMP1 and CD63 levels together was shown to correlate significantly with colony formation capacity.Conclusions: Our results show that Timp1 is assembled in a supramolecular complex containing CD63 and beta 1-integrins along melanoma genesis and confers anoikis resistance by activating PI3-K signaling pathway, independently of Akt phosphorylation. in addition, our data point TIMP1, mainly together with CD63, as a potential biomarker of melanoma.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Pharmacol, São Paulo, BrazilUniversidade Federal de São Paulo, Microbiol Immunol & Parasitol Dept, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biochem, São Paulo, BrazilLudwig Inst Canc Res, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pharmacol, São Paulo, BrazilUniversidade Federal de São Paulo, Microbiol Immunol & Parasitol Dept, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biochem, São Paulo, BrazilFAPESP: 2011/12306-1FAPESP: 2010/18715-8CAPES: 2867/10Web of Scienc

The Promigratory Activity of the Matricellular Protein Galectin-3 Depends on the Activation of PI-3 Kinase

Expression of galectin-3 is associated with sarcoma progression, invasion and metastasis. Here we determined the role of extracellular galectin-3 on migration of sarcoma cells on laminin-111. Cell lines from methylcholanthrene-induced sarcomas from both wild type and galectin-3−/− mice were established. Despite the presence of similar levels of laminin-binding integrins on the cell surface, galectin-3−/− sarcoma cells were more adherent and less migratory than galectin-3+/+ sarcoma cells on laminin-111. When galectin-3 was transiently expressed in galectin-3−/− sarcoma cells, it inhibited cell adhesion and stimulated the migratory response to laminin in a carbohydrate-dependent manner. Extracellular galectin-3 led to the recruitment of SHP-2 phosphatase to focal adhesion plaques, followed by a decrease in the amount of phosphorylated FAK and phospho-paxillin in the lamellipodia of migrating cells. The promigratory activity of extracellular galectin-3 was inhibitable by wortmannin, implicating the activation of a PI-3 kinase dependent pathway in the galectin-3 triggered disruption of adhesion plaques, leading to sarcoma cell migration on laminin-111