Heat shock protein 72 supports extracellular matrix production in metastatic mammary tumors.

This study identified tumorigenic processes most dependent on murine heat shock protein 72 (HSP72) in the mouse mammary tumor virus-PyMT mammary tumor model, which give rise to spontaneous mammary tumors that exhibit HSP72-dependent metastasis to the lung. RNA-seq expression profiling of Hspa1a/Hspa1b (Hsp72) WT and Hsp72-/- primary mammary tumors discovered significantly lower expression of genes encoding components of the extracellular matrix (ECM) in Hsp72 knockout mammary tumors compared to WT controls. In vitro studies found that genetic or chemical inhibition of HSP72 activity in cultured collagen-expressing human or murine cells also reduces mRNA and protein levels of COL1A1 and several other ECM-encoding genes. In search of a possible mechanistic basis for this relationship, we found HSP72 to support the activation of the tumor growth factor-ß-suppressor of mothers against decapentaplegic-3 signaling pathway and evidence of suppressor of mothers against decapentaplegic-3 and HSP72 coprecipitation, suggesting potential complex formation. Human COL1A1 mRNA expression was found to have prognostic value for HER2+ breast tumors over other breast cancer subtypes, suggesting a possible human disease context where targeting HSP72 may have a therapeutic rationale. Analysis of human HER2+ breast tumor gene expression data using a gene set comprising ECM-related gene and protein folding-related gene as an input to the statistical learning algorithm, Galgo, found a subset of these genes that can collectively stratify patients by relapse-free survival, further suggesting a potential interplay between the ECM and protein-folding genes may contribute to tumor progression.

MicroRNA-570 targets the HSP chaperone network, increases proteotoxic stress and inhibits mammary tumor cell migration.

The dynamic network of chaperone interactions known as the chaperome contributes significantly to the proteotoxic cell response and the malignant phenotype. To bypass the inherent redundancy in the network, we have used a microRNA (mir) approach to target multiple members of the chaperome simultaneously. We identified a potent microRNA, miR-570 that could bind the 3'untranslated regions of multiple HSP mRNAs and inhibit HSP synthesis. Transfection of cells with this miR species reduced expression of multiple HSPs, inhibited the heat shock response and reduced tumor cell growth while acted additively in combination with cytotoxic drugs. As overexpression of miR-570 elicited tumor suppressive effects, we inferred that this miR could play a potential role in inhibiting tumorigenesis and cancer cell growth. In accordance with this hypothesis, we determined a significant role for miR-570 in regulating markers of mammary tumor progression, including cell motility and invasion. Our data provide a proof of the principle that the tumor chaperome can be targeted by microRNAs suggesting a potential therapeutic avenue towards cancer therapy.

Carbonic anhydrase IX and hypoxia-inducible factor 1 attenuate cardiac dysfunction after myocardial infarction.

Myocardial infarction (MI) is one of the leading causes of death worldwide. Prognosis and mortality rate are directly related to infarct size and post-infarction pathological heart remodeling, which can lead to heart failure. Hypoxic MI-affected areas increase the expression of hypoxia-inducible factor (HIF-1), inducing infarct size reduction and improving cardiac function. Hypoxia translocates HIF-1 to the nucleus, activating carbonic anhydrase IX (CAIX) transcription. CAIX regulates myocardial intracellular pH, critical for heart performance. Our objective was to investigate CAIX participation and relation with sodium bicarbonate transporters 1 (NBC1) and HIF-1 in cardiac remodeling after MI. We analyzed this pathway in an "in vivo" rat coronary artery ligation model and isolated cardiomyocytes maintained under hypoxia. Immunohistochemical studies revealed an increase in HIF-1 levels after 2 h of infarction. Similar results were observed in 2-h infarcted cardiac tissue (immunoblotting) and in hypoxic cardiomyocytes with a nuclear distribution (confocal microscopy). Immunohistochemical studies showed an increase CAIX in the infarcted area at 2 h, mainly distributed throughout the cell and localized in the plasma membrane at 24 h. Similar results were observed in 2 h in infarcted cardiac tissue (immunoblotting) and in hypoxic cardiomyocytes (confocal microscopy). NBC1 expression increased in cardiac tissue after 2 h of infarction (immunoblotting). CAIX and NBC1 interaction increases in cardiac tissue subjected to MI for 2h when CAIX is present (immunoprecipitation). These results suggest that CAIX interacts with NBC1 in our infarct model as a mechanism to prevent acidic damage in hypoxic tissue, making it a promising therapeutic target.

Changes in prolactin receptor location in prostate tumors. / Cambios en la localización del receptor prolactina en tumores prostáticos.

INTRODUCTION: Prolactin (PRL) binds its receptor (PRLR) and stimulates cell proliferation, differentiation and survival in prostate cancer (PCa) cell lines via STAT5a, MAPK and AKT. OBJECTIVE: To evaluate the expression of PRL and PRLR in normal and tumor prostate tissues with different Gleason patterns. METHODS: Samples of normal, benign prostatic hyperplasia and PCa with different Gleason patterns were selected from radical prostatectomy. The intensity, location and percentage of stained cells for PRL and PRLR were evaluated by Immunohistochemistry. Co-localization was observed by confocal microscopy. RESULTS: PRL was expressed diffusely and with a mild intensity in the cytoplasm of normal and tumor prostate luminal cells. Its expression only augmented in the Gleason 3 pattern (p< 0.0001). The immunostaining intensity and the percentage of positive cells for PRLR did not vary between normal and tumor tissues. However, the location of the PRLR was modified by the tumorigenic process.In non-tumor tissues, PRLR expression was mostly in plasma membrane in the apical zone of epithelial cells. In tumor tissues, it was expressed in intracellular vesicles.The co-localization of PRL and PRLR was demonstrated in normal and tumor tissues suggesting that PRL could be acting in an autocrine and paracrine manner. CONCLUSION: PRL and its receptor were present in the cytoplasm of the epithelial cells of the normal and tumor prostate gland. In tumor tissues, the change in the location and appearance of cryptic PRLRs that store PRL may keep active the different signaling pathways related to cell proliferation and survival.

INTRODUCCIÓN: La prolactina (PRL) se une a su receptor (PRLR) y estimula la proliferación celular, la diferenciación y la supervivencia de la líneas celulares de cáncer de próstata vía STAT5a, MAPK y AKT.OBJETIVO: Evaluar la expresión de la PRL y PRLR en tejido normal y tejido de cáncer de próstata con varios patrones de Gleason.MÉTODOS: Se seleccionaron muestras de tejido benigno, hiperplasia y cáncer de próstata con diferentes patrones de Gleason de prostatectomías radicales. La intensidad, localización y porcentaje de células teñidas por PRL y PRLR fueron evaluadas por immunohistoquimica. La co-localización se observó con microscopio confocal.RESULTADOS: PRL se presentó de forma difusa y con intensidad media en el citoplasma de células luminales normales y de tumor prostático. La expresión solamente aumentó en patrón Gleason 3 (p<0,0001). La intensidad de la tinción immunohistoquímica y el porcentaje de células positivas para PRLR no varió entre células normales y tejidos tumorales. Pero, la localización del PRLR fue modificada por el proceso generador del tumor. En tejidos no-tumorales, la expresión de PRLR fue sobre todo en la membrana plasmática en la zona apical de las células epiteliales. En tejidos tumorales, se presentó en las vesículas intracelulares. La co-localizacion de la PRL y PRLR se demostró en tejido normal y tumoral sugeriendo que la PRL funciona con un efecto autocrino y paracrino.CONCLUSIÓN: La PRL y su receptor estuvieron presentes en el citoplasma de células epiteliales de tejido normal y glándula prostática tumoral. En tejidos tumorales, el cambio de localización y la apariencia cripticas del PRLR que guarda la PRL debe mantener activos los diferentes caminos de señalización relacionados con la proliferación celular y la supervivencia.

Changes in prolactin receptor location in prostate tumors / Cambios en la ubicación del receptor de prolactina en tumores de próstata

Introduction: Prolactin (PRL) binds its receptor (PRLR) and stimulates cell proliferation, differentiation and survival in prostate cancer (PCa) cell lines via STAT5a, MAPK and AKT. Objetive: To evaluate the expression of PRL and PRLR in normal and tumor prostate tissues with different Gleason patterns. Methos: Samples of normal, benign prostatic hyperplasia and PCa with different Gleason patterns were selected from radical prostatectomy. The intensity, location and percentage of stained cells for PRL and PRLR were evaluated by Immunohistochemistry. Co-localization was observed by confocal microscopy. Results: PRL was expressed diffusely and with a mild intensity in the cytoplasm of normal and tumor prostate luminal cells. Its expression only augmented in the Gleason 3 pattern (p 0.0001). The immunostaining intensity and the percentage of positive cells for PRLR did not vary between normal and tumor tissues. However, the location of the PRLR was modified by the tumorigenic process. In non-tumor tissues, PRLR expression was mostly in plasma membrane in the apical zone of epithelial cells. In tumor tissues, it was expressed in intracellular vesicles. The co-localization of PRL and PRLR was demonstrated in normal and tumor tissues suggesting that PRL could be acting in an autocrine and paracrine manner. Conclusion: PRL and its receptor were present in the cytoplasm of the epithelial cells of the normal and tumor prostate gland. In tumor tissues, the change in the location and appearance of cryptic PRLRs that store PRL may keep active the different signaling pathways related to cell proliferation and survival.(AU)

Introducción: La prolactina (PRL) se une a su receptor (PRLR) y estimula la proliferación celular, la diferenciación y la supervivencia de la líneas celulares de cáncer de próstata vía STAT5a, MAPK y AKT. Objetivo: Evaluar la expresión de la PRL y PRLR en tejido normal y tejido de cáncer de próstata con varios patrones de Gleason.MÉTODOS: Se seleccionaron muestras de tejido benigno, hiperplasia y cáncer de próstata con diferentes patrones de Gleason de prostatectomías radicales. La intensidad, localización y porcentaje de células teñidas por PRL y PRLR fueron evaluadas por immunohistoquimica. La co-localización se observó con microscopioconfocal. Resultados: PRL se presentó de forma difusa y con intensidad media en el citoplasma de células luminales normales y de tumor prostático. La expresión solamente aumentó en patrón Gleason 3 (p<0,0001). La intensidad de la tinción immunohistoquímica y el porcentajede células positivas para PRLR no varió entre células normales y tejidos tumorales. Pero, la localización del PRLR fue modificada por el proceso generador del tumor. En tejidos no-tumorales, la expresión de PRLR fue sobre todo en la membrana plasmática en la zona apical de las células epiteliales. En tejidos tumorales, se presentó en las vesículas intracelulares. La co-localizacion de la PRL y PRLR se demostró en tejido normal y tumoral sugeriendo que la PRL funciona con un efecto autocrino y paracrino. Conclusión: La PRL y su receptor estuvieron presentes en el citoplasma de células epiteliales de tejido normal y glándula prostática tumoral. En tejidos tumorales, el cambio de localización y la apariencia cripticas del PRLR que guarda la PRL debe mantener activos los diferentes caminos de señalización relacionados con laproliferación celular y la supervivencia.(AU)

HSF1: Primary Factor in Molecular Chaperone Expression and a Major Contributor to Cancer Morbidity.

Heat shock factor 1 (HSF1) is the primary component for initiation of the powerful heat shock response (HSR) in eukaryotes. The HSR is an evolutionarily conserved mechanism for responding to proteotoxic stress and involves the rapid expression of heat shock protein (HSP) molecular chaperones that promote cell viability by facilitating proteostasis. HSF1 activity is amplified in many tumor contexts in a manner that resembles a chronic state of stress, characterized by high levels of HSP gene expression as well as HSF1-mediated non-HSP gene regulation. HSF1 and its gene targets are essential for tumorigenesis across several experimental tumor models, and facilitate metastatic and resistant properties within cancer cells. Recent studies have suggested the significant potential of HSF1 as a therapeutic target and have motivated research efforts to understand the mechanisms of HSF1 regulation and develop methods for pharmacological intervention. We review what is currently known regarding the contribution of HSF1 activity to cancer pathology, its regulation and expression across human cancers, and strategies to target HSF1 for cancer therapy.

Comprehensive transcriptomic analysis of heat shock proteins in the molecular subtypes of human breast cancer.

BACKGROUND: Heat Shock Proteins (HSPs), a family of genes with key roles in proteostasis, have been extensively associated with cancer behaviour. However, the HSP family is quite large and many of its members have not been investigated in breast cancer (BRCA), particularly in relation with the current molecular BRCA classification. In this work, we performed a comprehensive transcriptomic study of the HSP gene family in BRCA patients from both The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) cohorts discriminating the BRCA intrinsic molecular subtypes. METHODS: We examined gene expression levels of 1097 BRCA tissue samples retrieved from TCGA and 1981 samples of METABRIC, focusing mainly on the HSP family (95 genes). Data were stratified according to the PAM50 gene expression (Luminal A, Luminal B, HER2, Basal, and Normal-like). Transcriptomic analyses include several statistical approaches: differential gene expression, hierarchical clustering and survival analysis. RESULTS: Of the 20,531 analysed genes we found that in BRCA almost 30% presented deregulated expression (19% upregulated and 10% downregulated), while of the HSP family 25% appeared deregulated (14% upregulated and 11% downregulated) (|fold change| > 2 comparing BRCA with normal breast tissues). The study revealed the existence of shared HSP genes deregulated in all subtypes of BRCA while other HSPs were deregulated in specific subtypes. Many members of the Chaperonin subfamily were found upregulated while three members (BBS10, BBS12 and CCTB6) were found downregulated. HSPC subfamily had moderate increments of transcripts levels. Various genes of the HSP70 subfamily were upregulated; meanwhile, HSPA12A and HSPA12B appeared strongly downregulated. The strongest downregulation was observed in several HSPB members except for HSPB1. DNAJ members showed heterogeneous expression pattern. We found that 23 HSP genes correlated with overall survival and three HSP-based transcriptional profiles with impact on disease outcome were recognized. CONCLUSIONS: We identified shared and specific HSP genes deregulated in BRCA subtypes. This study allowed the recognition of HSP genes not previously associated with BRCA and/or any cancer type, and the identification of three clinically relevant clusters based on HSPs expression patterns with influence on overall survival.

Manipulating the Alpha Level Cannot Cure Significance Testing.

We argue that making accept/reject decisions on scientific hypotheses, including a recent call for changing the canonical alpha level from p = 0.05 to p = 0.005, is deleterious for the finding of new discoveries and the progress of science. Given that blanket and variable alpha levels both are problematic, it is sensible to dispense with significance testing altogether. There are alternatives that address study design and sample size much more directly than significance testing does; but none of the statistical tools should be taken as the new magic method giving clear-cut mechanical answers. Inference should not be based on single studies at all, but on cumulative evidence from multiple independent studies. When evaluating the strength of the evidence, we should consider, for example, auxiliary assumptions, the strength of the experimental design, and implications for applications. To boil all this down to a binary decision based on a p-value threshold of 0.05, 0.01, 0.005, or anything else, is not acceptable.

Inorganic mercury in mammary cells: viability, metal uptake but efflux?

The viability, cellular uptake and subcellular distribution of heavy metal Hg, were determined in human mammary cell lines (MCF-7, MDA-MB-231 and MCF-10A). It was observed that Hg had the capacity of being excluded from the cells with a different type of possible transporters. MCF-7 cells showed the lowest viability, while the other two cell lines were much more resistant to Hg treatments. The intracellular concentration of Hg was higher at lower exposure times in MCF-10A cells and MCF-7 cells; but as the time was increased only MDA-MB-231 showed the capacity to continue introducing the metal. In MCF-7 and MCF-10A cells the subcellular distribution of Hg was higher in cytosolic fraction than nucleus and membrane, but MDA-MB-231 showed membrane and nucleus fraction as the enriched one. The analysis of RNA-seq about the genes or family of genes that encode proteins which are related to cytotoxicity of Hg evidenced that MCF-10A cells and MCF-7 cells could have an active transport to efflux the metal. On the contrary, in MDA-MB-231 no genes that could encode active transporters have been found.

TP73 DNA methylation and upregulation of ΔNp73 are associated with an adverse prognosis in breast cancer.

AIM: Accumulated evidence suggests that aberrant methylation of the TP73 gene and increased levels of ΔNp73 in primary tumours correlate with poor prognosis. However, little is known regarding the transcriptional and functional regulation of the TP73 gene in breast cancer. The aim of the present study was to determine the expression of the ΔNp73 isoform, its relationship with DNA methylation of TP73 and their clinical prognostic significance in breast cancer patients. METHODS: TP73 gene methylation was studied in TCGA datasets and in 70 invasive ductal breast carcinomas (IDCs). The expression of p73 isoforms was evaluated by immunohistochemistry (IHC) and Western blot and correlated with clinicopathological variables and clinical outcome. RESULTS: We observed that the methylation of diverse CpG islands of TP73 differed significantly between molecular subtypes. An inverse correlation was found between p73 protein expression and the methylation status of the TP73 gene. The expression of exon 3' of p73 (only expressed in ΔNp73) was significantly higher in patients with wild-type p53. Immunohistochemical analysis revealed that all p73 isoforms were localised in both the nuclear and cytoplasmic compartments. We confirmed a positive association between the expression of ∆Np73 and high histological grade. CONCLUSIONS: Our findings suggest that high expression of ΔNp73 could be used to determine the aggressiveness of IDCs and could be incorporated in the pathologist's report.

Molecular markers of DNA damage and repair in cervical cancer patients treated with cisplatin neoadjuvant chemotherapy: an exploratory study.

Neoadjuvant (or induction) chemotherapy can be used for cervical cancer patients with locally advanced disease; this treatment is followed by radical surgery and/or radiation therapy. Cisplatin is considered to be the most active platinum agent drug for this cancer, with a response rate of 20%. In order to understand how the cisplatin treatment affects the stress response, in this work, we performed an exploratory study to analyze a number of stress proteins before and after cisplatin neoadjuvant chemotherapy. The study involved 14 patients; the pre- and post-chemotherapy paired biopsies were examined by hematoxylin and eosin staining and by immunohistochemistry. The proteins evaluated were p53, P16/INK4A, MSH2, nuclear protein transcriptional regulator 1 (NUPR1), and HSPB1 (total: HSPB1/t and phosphorylated: HSPB1/p). These proteins were selected because there is previous evidence of their relationship with drug resistance. The formation of platinum-DNA adducts was also studied. There was a great variation in the expression levels of the mentioned proteins in the pre-chemotherapy biopsies. After chemotherapy, p53 was not significantly affected by cisplatin, as well as P16/INK4A and MSH2 while nuclear NUPR1 content tended to decrease (p = 0.056). Cytoplasmic HSPB1/t expression levels decreased significantly following cisplatin therapy while nuclear HSPB1/t and HSPB1/p tended to increase. Since the most significant changes following chemotherapy appeared in the HSPB1 expression levels, the changes were confirmed by Western blot. The platinum-DNA adducts were observed in HeLa cell in apoptosis; however, in the tumor samples, the platinum-DNA adducts were observed in morphologically healthy tumor cells; these cells displayed nuclear HSPB1/p. Further mechanistic studies should be performed to reveal how HSPB1/p is related with drug resistance. When the correlations of the markers with the response to neoadjuvant chemotherapy were examined, only high pre-chemotherapy levels of cytoplasmic HSPB1/p correlated with a poor clinical and pathological response to neoadjuvant cisplatin chemotherapy (p = 0.056) suggesting that this marker could be useful opening its study in a larger number of cases.