165 research outputs found
Modeling the paleogeography of north-western Palaeotethys across the Permian-Triassic boundary: constraints and possible solutions
We simulated for the first time the paleogeographicevolution of three thin depositional sequences of the shallowmarinewestern Palaeotethys, deposited in the Southern Alps (SA,Italy) during the devastating Permian-Triassic extinction. Thesimulation is calibrated by a rich set of published field data,measured in the uppermost Bellerophon Formation - lowermostWerfen Fm. Data and paleogeographic maps are located in theSA area palinspastically restored. The employed software is apreliminary version of SIMSAFADIM-CLASTIC, that simulates:a) the spatial distribution of terrigenous and clastic carbonate, b)the fossil content, c) the microbial content. The models (maps)were realized as a back-analysis, by calibration on the 3Darchitecture of the real sedimentary sequences, particularly onthe spatial distribution of terrigenous-clastic carbonate ratio. Thesimulation covers a period of about 70 kyr, whereas eachsedimentary sequence corresponds to a time span of 15-20 kyr;the low stand tract spans 5-6 kyr. The models that best match thereality was achieved by using a curve of sea level changesobtained empirically, by subsequent attempts. The maximum sealevel change is about a dozen meters, and the study areaunderwent locally short periods of emersion, with soil orintertidal carbonates, followed by shallow marine, foreshorefacies. This sea level changes curve is likely to represent theglobal reference. We interpret the model results in light of thehypothesis that the curve of sea level change presented here couldwere produced by alternating global warming and cooling of theoceans. This curve, obtained by an independent method, wouldbe utilized as an important constraint of the global atmospheric,coupled with oceanic circulation, numerical models. On thecontrary, the disappearence of Permian-type taxa (fusulinids,forams, bivalves and algae) pre-dating the P-T boundary does notmatch the field data, because the software is lacking a fewspecific functions; these biologic carbonate components seems tohave beeen substituted by, for a still unknown environmentalcause, the production of oolites and of carbonate of microbialiticorigin
Organic carbon content and carbon isotope variations across the Permo-Triassic boundary in the Gartnerkofel-1 borehole, Carnic Alps, Austria
The Gartnerkofel borehole is one of the most thoroughly studied and described Permo-Triassic sections in the world. Detailed bulk organic carbon isotope studies show a negative base shift from − 24‰ to − 28‰ in the Latest Permian which latter value persists into the Earliest Triassic after which it decreases slightly to − 26‰. Two strongly negative peaks of > − 38‰ in the Latest Permian and a lesser peak of − 31‰ in the Early Triassic are too negative to be due to a greater proportion of more negative organic matter and must be due to very negative methane effects. The overall change to more negative values across the Bulla/Tesero boundary fits the relative rise in sea level for this transition based on the facies changes. A positive shift in organic carbon isotope values at the Late Permian Event Horizon may be due to an increase in land-derived organic detritus at this level—a feature shown by all Tethyan Permo-Triassic boundary sections though these other sections do not have the same values. Carbonate carbon isotope trends are similar in all sections dropping by 2–3 units across the Permo-Triassic boundary. Gartnerkofel carbonate oxygen values are surprisingly, considering the ubiquitous dolomitization, compatible with values elsewhere and indicate reasonable tropical temperatures of 60 °C in the Latest Permian sabkhas to 20–40 °C in the overlying marine transition beds. Increased land-derived input at the Late Permian Event Horizon may be due to offshore transport by tsunamis whose deposits have been recognized in India at this level
Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds
The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting
HER2/neu overexpression in the development of muscle-invasive transitional cell carcinoma of the bladder
The mortality from transitional cell carcinoma (TCC) of the urinary bladder increases significantly with the progression of superficial or locally invasive disease (pTa/pT1) to detrusor muscle-invasive disease (pT2+). The most common prognostic markers in clinical use are tumour stage and grade, which are subject to considerable intra- and interobserver variation. Polysomy 17 and HER2/neu gene amplification and protein overexpression have been associated with more advanced disease. Standardised techniques of fluorescence in situ hybridisation and immunohistochemistry, which are currently applied to other cancers with a view to offering anti-HER2/neu therapies, were applied to tumour pairs comprising pre- and postinvasive disease from 25 patients undergoing treatment for bladder cancer. In the preinvasive tumours, increased HER2/neu copy number was observed in 76% of cases and increased chromosome 17 copy number in 88% of cases, and in the postinvasive group these values were 92 and 96%, respectively (not significantly different P=0.09 and 0.07, respectively). HER2 gene amplification rates were 8% in both groups. Protein overexpression rates were 76 and 52%, respectively, in the pre- and postinvasive groups (P=0.06). These results suggest that HER2/neu abnormalities occur prior to and persist with the onset of muscle-invasive disease. Gene amplification is uncommon and other molecular mechanisms must account for the high rates of protein overexpression. Anti-HER2/neu therapy might be of use in the treatment of TCC
Higher expression levels of SOCS 1,3,4,7 are associated with earlier tumour stage and better clinical outcome in human breast cancer
Background
Suppressors of cytokine signaling (SOCS) are important negative feedback regulators of the JAK/STAT signaling pathway, and have been recently investigated for their role in the development of different cancers. In this study, we examined the expression of SOCS1-7 genes in normal and breast cancer tissue and correlated this with several clinico-pathological and prognostic factors.
Methods
SOCS1-7 mRNA extraction and reverse transcription were performed on fresh frozen breast cancer tissue samples (n = 127) and normal background breast tissue (n = 31). Transcript levels of expression were determined using real-time PCR and analyzed against TNM stage, tumour grade and clinical outcome over a 10 year follow-up period.
Results
SOCS1,4,5,6 and 7 expression decreased with increased TNM stage (TNM1 vs. TNM3 p = 0.039, TNM1 vs. TNM4 p = 0.016, TNM2 vs. TNM4 p = 0.025, TNM1 vs. TNM3 p = 0.012, and TNM1 vs. TNM3 p = 0.044 respectively). SOCS2 and 3 expression decreased with increased Nottingham Prognostic Index (NPI) (NPI1 vs. NPI3 p = 0.033, and NPI2 vs. NPI3 p = 0.041 respectively). SOCS7 expression decreased with higher tumour grade (Grade 3 vs. Grade 2 p = 0.037). After a median follow up period of 10 years, we found higher levels of SOCS1,2 and 7 expression among those patients who remained disease-free compared to those who developed local recurrence (p = 0.0073, p = 0.021, and p = 0.039 respectively). Similarly, we found higher levels of SOCS 2,4, and 7 expression in those who remained disease-free compared to those who developed distant recurrence (p = 0.022, p = 0.024, and p = 0.033 respectively). Patients who remained disease-free had higher levels of SOCS1 and 2 expression compared to those who died from breast cancer (p = 0.02 and p = 0.033 respectively). The disease free survival (DFS) and overall survival (OS) curves showed that higher levels of SOCS1, 3 and 7 were significant predictors of higher DFS (p = 0.015, p = 0.024 and 0.03 respectively) and OS (p = 0.005, p = 0.013 and p = 0.035 respectively). Higher levels of SOCS 4 were significant in predicting better OS (p = 0.007) but not DFS. Immunohistochemical staining of representative samples showed a correlation between SOCS1, 3, 7 protein staining and the SOCS1, 3, 7 mRNA expression.
Conclusion
Higher mRNA expression levels of SOCS1, 3, 4 and 7 are significantly associated with earlier tumour stage and better clinical outcome in human breast cancer
Favorable prognostic value of SOCS2 and IGF-I in breast cancer
<p>Abstract</p> <p>Background</p> <p>Suppressor of cytokine signaling (SOCS) proteins comprise a protein family, which has initially been described as STAT induced inhibitors of the Jak/Stat pathway. Recent in vivo and in vitro studies suggest that SOCS proteins are also implicated in cancer. The STAT5 induced IGF-I acts as an endocrine and para/autocrine growth and differentiation factor in mammary gland development. Whereas high levels of circulating IGF-I have been associated with increased cancer risk, the role of autocrine acting IGF-I is less clear. The present study is aimed to elucidate the clinicopathological features associated with SOCS1, SOCS2, SOCS3, CIS and IGF-I expression in breast cancer.</p> <p>Methods</p> <p>We determined the mRNA expression levels of SOCS1, SOCS2, SOCS3, CIS and IGF-I in 89 primary breast cancers by reverse transcriptase PCR. SOCS2 protein expression was further evaluated by immuno-blot and immunohistochemistry.</p> <p>Results</p> <p>SOCS2 expression inversely correlated with histopathological grade and ER positive tumors exhibited higher SOCS2 levels. Patients with high SOCS2 expression lived significantly longer (108.7 vs. 77.7 months; P = 0.015) and high SOCS2 expression proved to be an independent predictor for good prognosis (HR = 0.45, 95% CI 0.23 – 0.91, P = 0.026). In analogy to SOCS2, high IGF-I expression was an independent predictor for good prognosis in the entire patient cohort. In the subgroup of patients with lymph-node negative disease, high IGF-I was a strong predictor for favorable outcome in terms of overall survival and relapse free survival (HR = 0.075, 95% CI 0.014 – 0.388, P = 0.002).</p> <p>Conclusion</p> <p>This is the first report on the favorable prognostic value of high SOCS2 expression in primary mammary carcinomas. Furthermore a strong association of high IGF-I expression levels with good prognosis was observed especially in lymph-node negative patients. Our results suggest that high expression of the STAT5 target genes SOCS2 and IGF-I is a feature of differentiated and less malignant tumors.</p
BRCA1-mutated and basal-like breast cancers have similar aCGH profiles and a high incidence of protein truncating TP53 mutations
<p>Abstract</p> <p>Background</p> <p>Basal-like breast cancers (BLBC) are aggressive breast cancers for which, so far, no targeted therapy is available because they typically lack expression of hormone receptors and HER2. Phenotypic features of BLBCs, such as clinical presentation and early age of onset, resemble those of breast tumors from <it>BRCA1</it>-mutation carriers. The genomic instability of <it>BRCA1</it>-mutated tumors can be effectively targeted with DNA-damaging agents and poly-(ADP-ribose) polymerase 1 (PARP1) inhibitors. Molecular similarities between BLBCs and <it>BRCA1</it>-mutated tumors may therefore provide predictive markers for therapeutic response of BLBCs.</p> <p>Methods</p> <p>There are several known molecular features characteristic for <it>BRCA1</it>-mutated breast tumors: 1) increased numbers of genomic aberrations, 2) a distinct pattern of genomic aberrations, 3) a high frequency of <it>TP53 </it>mutations and 4) a high incidence of complex, protein-truncating <it>TP53 </it>mutations. We compared the frequency of <it>TP53 </it>mutations and the pattern and amount of genomic aberrations between <it>BRCA1</it>-mutated breast tumors, BLBCs and luminal breast tumors by <it>TP53 </it>gene sequencing and array-based comparative genomics hybridization (aCGH) analysis.</p> <p>Results</p> <p>We found that the high incidence of protein truncating <it>TP53 </it>mutations and the pattern and amount of genomic aberrations specific for BRCA1-mutated breast tumors are also characteristic for BLBCs and different from luminal breast tumors.</p> <p>Conclusions</p> <p>Complex, protein truncating TP53 mutations in BRCA1-mutated tumors may be a direct consequence of genomic instability caused by BRCA1 loss, therefore, the presence of these types of TP53 mutations in sporadic BLBCs might be a hallmark of BRCAness and a potential biomarker for sensitivity to PARP inhibition. Also, our data suggest that a small subset of genomic regions may be used to identify BRCA1-like BLBCs. BLBCs share molecular features that were previously found to be specific for BRCA1-mutated breast tumors. These features might be useful for the identification of tumors with increased sensitivity to (high-dose or dose-dense) alkylating agents and PARP inhibitors.</p
Adaptive strategies and environmental significance of lingulid brachiopods across the late Permian extinction
Approccio multidisciplinare allo studio delle variazioni ambientali: simulazioni numeriche dell'evoluzione di prismi sedimentari durante i due eventi di estinzione globale ai limiti Permiano-Triassico e Frasniano-Famenniano, temporalmente vincolate e calibrate dalla dinamica faunistica.
L\u2019obiettivo principale di questa ricerca multidisciplinare \ue8 di fornire, per la prima volta, una valutazione quantitativa di alcuni parametri dipendenti dal clima in corrispondenza di due dei \u201cCinque Grandi\u201d eventi di estinzione globale: le crisi al limite Permiano\u2013Triassico (P\u2013T) e Frasniano\u2013Famenniano (Fr\u2013Fm). Entrambe sono espresse in successioni stratigrafiche in Alpi Meridionali. Per simulare la complessa architettura dei prismi sedimentari al limite P\u2013T e Fr\u2013Fm, verr\ue0 usato il software \u201cBasin\u201d, un modellatore in grado di controllare un elevato numero di parametri che sar\ue0 calibrato coi dati stratigrafici regionali di estremo dettaglio.
Lo studio pilota sar\ue0 quello al limite P\u2013T in Alpi Meridionali, per la ricca quantit\ue0 di dati a disposizione sulla litostratigrafia e sulle facies, distribuite quasi in continuit\ue0 su di una vasta area e ben rappresentate dalla sezione di Bulla.
In questo lavoro utilizzeremo i conodonti e gruppi di fossili in associazione quali i palinomorfi, per analizzare in dettaglio le modalit\ue0 evolutive dei conodonti e degli altri fossili ai cambiamenti ambientali. L\u2019interpretazione della dinamica faunistica nelle sequenze studiate sar\ue0 basata sui dati tassonomici, biostratigrafici e sedimentologici. I dati isotopici su matrice carbonatica e sostanza organica, saranno utili a riconoscere le variazioni del chimismo oceanico e forniranno una dimensione addizionale ai dati paleontologici e sedimentologici.
La simulazione sar\ue0 vincolata con dati cronostratigrafici (datazioni radiometriche) e paleomagnetici ottenuti da altre sezioni coeve, come quella dello stratotipo in Cina. Questi saranno usati per svolgere le simulazioni di analisi retrograde vincolate dalle architetture delle litofacies osservate e dalle geometrie. Queste simulazioni forniranno stime calibrate di parametri come il flusso di calore, la geometria della superficie trasgressiva di base, tassi di subsidenza tettonica e compattazione-dissoluzione di sedimenti, variazione della falda e fluttuazioni eustatiche.
Uguale metodo di studio sar\ue0 applicato al limite Fr\u2013Fm a partire da due sezioni (di mare basso e bacinale) delle Alpi Carniche
Ancient and modern stratigraphical methods put to the crucial test of the end\u2013Permian biological crisis
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