Institute Du Cancer Of Montreal
Institute Du Cancer Of Montreal
Baruah P.S.,Center Hospitalier Of Luniversite Of Montreal Crchum |
Beauchemin M.,Institute Du Cancer Of Montreal |
Parker J.A.,University of Montréal |
Bertrand R.,University of Montréal
PLoS ONE | Year: 2017
An interesting feature of Bcl-xL protein is the presence of an unstructured loop domain between α1 and α2 helices, a domain not essential for its anti-apoptotic function and absent in CED-9 protein. Within this domain, Bcl-xL undergoes dynamic phosphorylation and dephosphorylation at Ser49 and Ser62 during G2 and mitosis in human cells. Studies have revealed that when these residues are mutated, cells harbour mitotic defects, including chromosome mis-attachment, lagging, bridging and mis-segregation with, ultimately, chromosome instability and aneuploidy. We undertook genetic experiments in Caenorhabditis elegans to understand the importance of Bcl-xL (Ser49) and (Ser62) in vivo. Transgenic worms carrying single-site S49A, S62A, S49D, S62D and dual site S49/62A mutants were generated and their effects were analyzed in germlines of young adult worms. Worms expressing Bcl-xL variants showed decreased egg-laying and hatching potency, variations in the length of their mitotic regions but not of their transition zones, appearance of chromosomal abnormalities at their diplotene stages, and increased germline apoptosis, with the exception of the S62D variants. Some of these transgenic strains, particularly the Ser to Ala variants, also showed slight modulations of lifespan compared to their controls. In addition, RNAi experiments silencing expression of the various Bcl-xL variants reversed their effects in vivo. Our in vivo observations confirmed the importance of Ser49 and Ser62 within Bcl-xL loop domain in maintaining chromosome stability. © 2017 Baruah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Layoun A.,Institute Du Cancer Of Montreal |
Santos M.M.,Institute Du Cancer Of Montreal |
Santos M.M.,University of Montréal
Inflammation | Year: 2012
Abstract-Hepcidin is a key regulator of iron recycling by macrophages that is synthesized mainly by hepatocytes but also by macrophages. However, very little is known about the molecular regulation of hepcidin in macrophages. In the present study, we investigated hepcidin regulation in the RAW264.7 macrophage cell line and in murine peritoneal macrophages stimulated with different Toll-like receptor (TLR) ligands. We found that TLR-2 and TLR-4 ligands activated hepcidin expression in RAW264.7 cells and inwild-typemurine peritoneal macrophages, but not in murine peritoneal macrophages isolated from TLR2-/-, TLR-4-deficient orMyD88-/- mice. IL-6 production by RAW264.7 cells stimulated with lipopolysaccharide (LPS, TLR4 ligand) was enhanced by high amounts of iron present in the culture medium.We conclude that hepcidin expression in macrophages is regulated mainly through TLR2 and TLR4 receptors via the MyD88-dependent signaling pathway and that autocrine regulation of iron accumulation in macrophages by hepcidin may affect the levels of proinflammatory cytokine production. © 2012 Springer Science+Business Media, LLC.
Meunier L.,Institute Du Cancer Of Montreal |
Madore J.,Institute Du Cancer Of Montreal |
Provencher D.,Institute Du Cancer Of Montreal |
Mes-Masson A.-M.,Institute Du Cancer Of Montreal
BMC Cancer | Year: 2013
Background: The X-linked ribosomal protein S4 (RPS4X), which is involved in cellular translation and proliferation, has previously been identified as a partner of the overexpressed multifunctional protein YB-1 in several breast cancer cells. Depletion of RPS4X results in consistent resistance to cisplatin in such cell lines.Methods: As platinum-based chemotherapy is a standard first line therapy used to treat patients with ovarian cancer, we evaluated the prognostic value of RPS4X and YB-1 at the protein level in specimen from 192 high-grade serous epithelial ovarian cancer patients.Results: Immunohistochemistry studies indicated that high expression of RPS4X was associated with a lower risk of death and later disease progression (HR = 0.713, P = 0.001 and HR = 0.761, P = 0.001, respectively) as compared to low expression of RPS4X. In contrast, YB-1 was not significantly associated with either recurrence or survival time in this cohort. Finally, the depletion of RPS4X with different siRNAs in two different ovarian cancer cell lines reduced their proliferative growth rate but more importantly increased their resistance to cisplatin.Conclusion: Altogether, these results suggest that the levels of RPS4X could be a good indicator for resistance to platinum-based therapy and a prognostic marker for ovarian cancer. Our study also showed that RPS4X is an independent prognostic factor in patients with serous epithelial ovarian cancer. © 2013 Tsofack et al.; licensee BioMed Central Ltd.
PubMed | Université de Sherbrooke and Institute Du Cancer Of Montreal
Type: Journal Article | Journal: Oncotarget | Year: 2016
Chromosomal and genome abnormalities at the 3p21.3 locus are frequent events linked to epithelial cancers, including ovarian and breast cancers. Genes encoded in the 3p21.3 cluster include HYAL1, HYAL2 and HYAL3 members of hyaluronidases involved in the breakdown of hyaluronan, an abundant component of the vertebrate extracellular matrix. However, the transcriptional regulation of HYAL genes is poorly defined. Here, we identified the estrogen receptor ER as a negative regulator of HYAL1 expression in breast cancer cells. Integrative data mining using METABRIC dataset revealed a significant inverse correlation between ER and HYAL1 gene expression in human breast tumors. ChIP-Seq analysis identified several ER binding sites within the 3p21.3 locus, supporting the role of estrogen as an upstream signal that diversely regulates the expression of 3p21.3 genes at both proximal and distal locations. Of these, HYAL1 was repressed by estrogen through ER binding to a consensus estrogen response element (ERE) located in the proximal promoter of HYAL1 and flanked by an Sp1 binding site, required to achieve optimal estrogen repression. The repressive chromatin mark H3K27me3 was increased at the proximal HYAL1 ERE but not at other EREs contained in the cluster, providing a mechanism to selectively downregulate HYAL1. The HYAL1 repression was also specific to ER and not to ER, whose expression did not correlate with HYAL1 in human breast tumors. This study identifies HYAL1 as an ER target gene and provides a functional framework for the direct effect of estrogen on 3p21.3 genes in breast cancer cells.
Parent N.,Institute Du Cancer Of Montreal |
Scherer M.,University of Regensburg |
Liebisch G.,University of Regensburg |
Schmitz G.,University of Regensburg |
And 2 more authors.
International Journal of Oncology | Year: 2011
A lysosomal pathway, characterized by the partial rupture or labilization of lysosomal membranes (LLM) and cathepsin release into the cytosol, is evoked during the early events of 20-S-camptothecin lactone (CPT)-induced apoptosis in human cancer cells, including human histiocytic lymphoma U-937 cells. These lysosomal events begin rapidly and simultaneously with mitochondrial permeabilization and caspase activation within 3 h after drug treatment. Recently, in a comparative proteomics analysis performed on highlyenriched lysosomal extracts, we identified proteins whose translocation to lysosomes correlated with LLM induction after CPT treatment, including protein kinase C-δ (PKC-δ). In this study, we show that the PKC-δ translocation to lysosomes is required for LLM, as silencing its expression with RNA interference or suppressing its activity with the inhibitor, rottlerin, prevents CPT-induced LLM. PKC-δ translocation to lysosomes is associated with lysosomal acidic sphingomyelinase (ASM) phosphorylation and activation, which in turn leads to an increase in ceramide (CER) content in lysosomes. The accumulation of endogenous CER in lysosomes is a critical event for CPT-induced LLM as suppressing PKC-δ or ASM activity reduces both the CPT-mediated CER generation in lysosomes and CPT-induced LLM. These findings reveal a novel mechanism by which PKC-δ mediates ASM phosphorylation/activation and CER accumulation in lysosomes in CPT-induced LLM, rapidly activating the lysosomal pathway of apoptosis after CPT treatment.
Lessard L.,McGill University |
Labbe D.P.,McGill University |
Deblois G.,McGill University |
Begin L.R.,Service dAnatomopathologie |
And 8 more authors.
Cancer Research | Year: 2012
The androgen receptor (AR) signaling axis plays a key role in the pathogenesis of prostate cancer. In this study, we found that the protein tyrosine phosphatase PTP1B, a well-established regulator of metabolic signaling, was induced after androgen stimulation of AR-expressing prostate cancer cells. PTP1B induction by androgen occurred at the mRNA and protein levels to increase PTP1B activity. High-resolution chromosome mapping revealed AR recruitment to two response elements within the first intron of the PTP1B encoding gene PTPN1, correlating with an AR-mediated increase in RNA polymerase II recruitment to the PTPN1 transcriptional start site. We found that PTPN1 and AR genes were coamplified in metastatic tumors and that PTPN1 amplification was associated with a subset of high-risk primary tumors. Functionally, PTP1B depletion delayed the growth of androgen-dependent human prostate tumors and impaired androgen-induced cell migration and invasion in vitro. However, PTP1B was also required for optimal cell migration of androgen-independent cells. Collectively, our results established the AR as a transcriptional regulator of PTPN1 transcription and implicated PTP1B in a tumor-promoting role in prostate cancer. Our findings support the preclinical testing of PTP1B inhibitors for prostate cancer treatment. ©2012 AACR.
Saad F.,University of Montréal |
Saad F.,Institute Du Cancer Of Montreal |
Pantel K.,University of Hamburg
Future Oncology | Year: 2012
Prostate-specific antigen (PSA) has been used for over two decades as a serum marker for adenocarcinoma of the prostate. Although PSA screening remains an important part of disease screening and monitoring in early prostate cancer (PC), its utility in monitoring disease progression in advanced PC is undetermined. Furthermore, the role of PSA monitoring in the management of patients with PC and bone metastases appears limited. The purpose of this review is to evaluate the role of circulating tumor cells (CTCs) as potential novel biomarkers in advanced PC. We present a review of CTC testing and the clinical data supporting the prognostic potential of CTCs in this setting. We propose that combination of CTCs and PSA velocity or doubling-time assessments may offer insights into the prognosis and management of advanced PC. © 2012 Future Medicine Ltd.
Rodier F.,Institute Du Cancer Of Montreal
Methods in Molecular Biology | Year: 2013
Cellular senescence suppresses cancer by eliminating potentially oncogenic cells, participates in tissue repair, contributes to cancer therapy, and promotes organismal aging. Numerous activities of senescent cells depend on the aptitude of these cells to secrete myriads of bioactive molecules, a behavior termed the senescence-associated secretory phenotype (SASP). The SASP supports cell-autonomous functions like the senescence-associated growth arrest, and mediates paracrine interactions between senescent cells and their surrounding microenvironment. The biological functions and the regulation of the SASP are beginning to emerge, and current SASP assessment techniques include the analysis of SASP factors at the mRNA level, the direct measurement of factors inside or outside the cell (i.e., secreted), and the detection of SASPprovoked cellular responses. Here, we focus on a simple approach to collect SASP-conditioned media in order to directly measure secreted SASP factors using sandwich enzyme-linked immunosorbent assay. As an example, we discuss the assessment of the major SASP factor interleukin-6 in senescent human fibroblasts. Supplemental notes are provided to easily adapt this procedure to other SASP factors, change cell types, or scale the techniques for different volumes or high-throughput measurements. These techniques should facilitate the discovery of novel functions and regulators of the SASP. © Springer Science+Business Media New York 2013.
Brissette M.-J.,University of Montréal |
Brissette M.-J.,Institute Du Cancer Of Montreal |
Lepage S.,University of Montréal |
Lepage S.,Institute Du Cancer Of Montreal |
And 7 more authors.
PLoS ONE | Year: 2012
Apoptotic endothelial cells are an important component of the "response to injury" process. Several atherosclerosis risk factors such as hyperglycemia and oxidized low-density lipoproteins, and immune injuries, such as antibodies and complement, induce endothelial cell apoptosis. While endothelial cell apoptosis is known to affect neighboring vascular wall cell biology, its consequences on macrophage reprogramming are ill defined. In this study, we report that apoptosis of human and mouse endothelial cells triggers the release of milk fat globule-epidermal growth factor 8 (MFG-E8) and reprograms macrophages into an anti-inflammatory cells. We demonstrated that MFG-E8 is released by apoptotic endothelial cells in a caspase-3-dependent manner. When macrophages were exposed to conditioned media from serum-starved apoptotic endothelial cells, they adopt a high anti-inflammatory, low pro-inflammatory cytokine/chemokine secreting phenotype that is lost if MFG-E8 is absent from the media. Macrophage treatment with recombinant MFG-E8 recapitulates the effect of conditioned media. Finally, we showed that MFG-E8-mediated reprogramming of macrophages occurs through increased phosphorylation of signal transducer and activator of transcription-3 (STAT-3). Taken together, our study suggests a key role of MFG-E8 release from apoptotic endothelial cells in macrophage reprogramming and demonstrates the importance of the apoptotic microenvironment in anti-inflammatory macrophage responses. © 2012 Brissette et al.
Cousineau I.,University of Montréal |
Cousineau I.,Institute Du Cancer Of Montreal |
Belmaaza A.,University of Montréal |
Belmaaza A.,Institute Du Cancer Of Montreal
Molecular Genetics and Genomics | Year: 2011
EMSY links the BRCA2 pathway to sporadic breast/ovarian cancer. It encodes a nuclear protein that binds to the BRCA2 N-terminal domain implicated in chromatin/transcription regulation, but when sporadically amplified/ overexpressed, increased EMSY level represses BRCA2 transactivation potential and induces chromosomal instability, mimicking the activity of BRCA2 mutations in the development of hereditary breast/ovarian cancer. In addition to chromatin/transcription regulation, EMSY may also play a role in the DNA-damage response, suggested by its ability to localize at chromatin sites of DNA damage/repair. This implies that EMSY overexpression may also repress BRCA2 in DNA-damage replication/checkpoint and recombination/repair, coordinated processes that also require its interacting proteins: PALB2, the partner and localizer of BRCA2; RPA, replication/checkpoint protein A; and RAD51, the inseparable recombination/repair enzyme. Here, using a well-characterized recombination/repair assay system, we demonstrate that a slight increase in EMSY level can indeed repress these two processes independently of transcriptional interference/repression. Since EMSY, RPA and PALB2 all bind to the same BRCA2 region, these findings further support a scenario wherein: (a) EMSY amplification may mimic BRCA2 deficiency, at least by overriding RPA and PALB2, crippling the BRCA2/RAD51 complex at DNA-damage and replication/transcription sites; and (b) BRCA2/RAD51 may coordinate these processes by employing at least EMSY, PALB2 and RPA. We extensively discuss the molecular details of how this can happen to ascertain its implications for a novel recombination mechanism apparently conceived as checkpoint rather than a DNA repair system for cell division, survival, death, and human diseases, including the tissue specificity of cancer predisposition, which may renew our thinking about targeted therapy and prevention. © The Author(s) 2011.