The metastasis inducer CCN1 (CYR61) activates the fatty acid synthase (FASN)-driven lipogenic phenotype in breast cancer cells

The angiogenic inducer CCN1 (Cysteine-rich 61, CYR61) is differentially activated in metastatic breast carcinomas. However, little is known about the precise mechanisms that underlie the pro-metastatic actions of CCN1. Here, we investigated the impact of CCN1 expression on fatty acid synthase (FASN), a metabolic oncogene thought to provide cancer cells with proliferative and survival advantages. Forced expression of CCN1 in MCF-7 cells robustly up-regulated FASN protein expression and also significantly increased FASN gene promoter activity 2- to 3-fold, whereas deletion of the sterol response element-binding protein (SREBP) binding site in the FASN promoter completely abrogated CCN1-driven transcriptional activation. Pharmacological blockade of MAPK or PI-3´K activation similarly prevented the ability of CCN1 to induce FASN gene activation. Pharmacological inhibition of FASN activity with the mycotoxin cerulenin or the small compound C75 reversed CCN1-induced acquisition of estrogen independence and resistance to hormone therapies such as tamoxifen and fulvestrant in anchorage-independent growth assays. This study uncovers FASNdependent endogenous lipogenesis as a new mechanism controlling the metastatic phenotype promoted by CCN1. Because estrogen independence and progression to a metastatic phenotype are hallmarks of therapeutic resistance and mortality in breast cancer, this previously unrecognized CCN1-driven lipogenic phenotype represents a novel metabolic target to clinically manage metastatic disease progression.Fil: Menendez, Javier A.. Instituto Catalán de Oncología; España. Institut d; EspañaFil: Vellón, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Espinoza, Ingrid. University Of Mississippi; Estados UnidosFil: Lupu, Ruth. Mayo Clinic Cancer Center; Estados Unido

Heregulin drives endocrine resistance by altering il-8 expression in er-positive breast cancer

Sustained HER2/HER3 signaling due to the overproduction of the HER3 ligand heregulin (HRG) is proposed as a key contributor to endocrine resistance in estrogen receptor-positive (ER+) breast cancer. The molecular mechanisms linking HER2 transactivation by HRG-bound HER3 to the acquisition of a hormone-independent phenotype in ER+ breast cancer is, however, largely unknown. Here, we explored the possibility that autocrine HRG signaling drives cytokine-related endocrine resistance in ER+ breast cancer cells. We used human cytokine antibody arrays to semi-quantitatively measure the expression level of 60 cytokines and growth factors in the extracellular milieu of MCF-7 cells engineered to overexpress full-length HRGβ2 (MCF-7/HRG cells). Interleukin-8 (IL-8), a chemokine closely linked to ER inaction, emerged as one the most differentially expressed cytokines. Cytokine profiling using structural deletion mutants lacking both the N-terminus and the cytoplasmic-transmembrane region of HRGβ2—which is not secreted and cannot transactivate HER2—or lacking a nuclear localization signal at the N-terminus—which cannot localize at the nucleus but is actively secreted and transactivates HER2—revealed that the HRG-driven activation of IL-8 expression in ER+ cells required HRG secretion and transactivation of HER2 but not HRG nuclear localization. The functional blockade of IL-8 with a specific antibody inversely regulated ERα-driven transcriptional activation in endocrine-sensitive MCF-7 cells and endocrine-resistant MCF-7/HRG cells. Overall, these findings suggest that IL-8 participates in the HRG-driven endocrine resistance program in ER+/HER2- breast cancer and might illuminate a potential clinical setting for IL8- or CXCR1/2-neutralizing antibodies.Fil: Papadimitropoulou, Adriana. Academy of Athens; GreciaFil: Vellón, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Atlas, Ella. University of Ottawa; CanadáFil: Steen, Travis Vander. Mayo Clinic; Estados UnidosFil: Cuyàs, Elisabet. Institut D'investigació Biomèdica de Girona Dr. Josep Trueta; España. Institut Català d'Oncologia; EspañaFil: Verdura, Sara. Institut Català d'Oncologia; España. Institut D'investigació Biomèdica de Girona Dr. Josep Trueta; EspañaFil: Espinoza, Ingrid. University of Mississippi; Estados UnidosFil: Menendez, Javier A.. Institut Català d'Oncologia; España. Institut D'investigació Biomèdica de Girona Dr. Josep Trueta; EspañaFil: Lupu, Ruth. Mayo Clinic; Estados Unidos. University of Ottawa; Canadá. Mayo Clinic Cancer Center; Estados Unido

Binding of the angiogenic/senescence inducer CCN1/CYR61 to integrin α6β1 drives endocrine resistance in breast cancer cells

CCN1/CYR61 promotes angiogenesis, tumor growth and chemoresistance by binding to its integrin receptor αvβ3 in endothelial and breast cancer (BC) cells. CCN1 controls also tissue regeneration by engaging its integrin receptorα6β1 to induce fibroblast senescence. Here, we explored if the ability of CCN1 to drive an endocrine resistancephenotype in estrogen receptor-positive BC cells relies on interactions with either αvβ3 or α6β1. First, we tookadvantage of site-specific mutagenesis abolishing the CCN1 receptor-binding sites to αvβ3 and α6β1 to determine theintegrin partner responsible for CCN1-driven endocrine resistance. Second, we explored a putative nuclear role ofCCN1 in regulating ERα-driven transcriptional responses. Retroviral forced expression of a CCN1 derivative with asingle amino acid change (D125A) that abrogates binding to αvβ3 partially phenocopied the endocrine resistancephenotype induced upon overexpression of wild-type (WT) CCN1. Forced expression of the CCN1 mutant TM,which abrogates all the T1, H1, and H2 binding sites to α6β1, failed to bypass the estrogen requirement foranchorage-independent growth or to promote resistance to tamoxifen. Wild-type CCN1 promoted estradiol-independent transcriptional activity of ERα and enhanced ERα agonist response to tamoxifen. The α6β1-binding-defective TM-CCN1 mutant lost the ERα co-activator-like behavior of WT-CCN1. Co-immunoprecipitation assaysrevealed a direct interaction between endogenous CCN1 and ERα, and in vitro approaches confirmed the ability ofrecombinant CCN1 to bind ERα. CCN1 signaling via α6β1, but not via αvβ3, drives an endocrine resistance phenotypethat involves a direct binding of CCN1 to ERα to regulate itstranscriptional activity in ER+ BC cells.Fil: Espinoza, Ingrid. University of Mississippi; Estados Unidos. Mayo Clinic ; Estados UnidosFil: Yang, Lin. Mayo Clinic ; Estados UnidosFil: Steen, Travis Vander. Mayo Clinic ; Estados UnidosFil: Vellón, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cuyàs, Elisabet. Institut D`investigació Biomedica de Girona Dr. Josep Trueta (idib`gi); EspañaFil: Verdura, Sara. Institut D`investigació Biomedica de Girona Dr. Josep Trueta (idib`gi); EspañaFil: Lau, Lester. Institut D`investigació Biomedica de Girona Dr. Josep Trueta (idib`gi); España. University of Illinois; Estados UnidosFil: Menendez, Javier A.. Institut D`investigació Biomedica de Girona Dr. Josep Trueta (idib`gi); EspañaFil: Lupu, Ruth. Institut D`investigació Biomedica de Girona Dr. Josep Trueta (idib`gi); Españ

Progesterone receptor isoform-dependent cross-talk between prolactin and fatty acid synthase in breast cancer

Progesterone receptor (PR) isoforms can drive unique phenotypes in luminal breast cancer (BC). Here, we hypothesized that PR-B and PR-A isoforms differentially modify the cross-talk between prolactin and fatty acid synthase (FASN) in BC. We profiled the responsiveness of the FASN gene promoter to prolactin in T47Dco BC cells constitutively expressing PR-A and PR-B, in the PR-null variant T47D-Y cell line, and in PR-null T47D-Y cells engineered to stably re-express PR-A (T47D-YA) or PR-B (T47D-YB). The capacity of prolactin to up-regulate FASN gene promoter activity in T47Dco cells was lost in T47D-Y and TD47-YA cells. Constitutively up-regulated FASN gene expression in T47-YB cells and its further stimulation by prolactin were both suppressed by the prolactin receptor antagonist hPRL-G129R. The ability of the FASN inhibitor C75 to decrease prolactin secretion was more conspicuous in T47-YB cells. In T47D-Y cells, which secreted notably less prolactin and downregulated prolactin receptor expression relative to T47Dco cells, FASN blockade resulted in an augmented secretion of prolactin and up-regulation of prolactin receptor expression. Our data reveal unforeseen PR-B isoform-specific regulatory actions in the cross-talk between prolactin and FASN signaling in BC. These findings might provide new PR-B/FASN-centered predictive and therapeutic modalities in luminal intrinsic BC subtypesFil: Menendez, Javier A.. Institut Català d'Oncologia; España. Institut d’Investigació Biomèdica de Girona; EspañaFil: Peirce, Susan K.. Clemson University. Pearce Center Professional Communication; Estados UnidosFil: Papadimitropoulou, Adriana. Biomedical Research Foundation Academy of Athens; GreciaFil: Cuyàs, Elisabet. Institut Català d'Oncologia; España. Institut d’Investigació Biomèdica de Girona; EspañaFil: Steen, Travis Vander. Mayo Foundation for Medical Education and Research. Mayo Clinic; Estados UnidosFil: Verdura, Sara. Institut Català d'Oncologia; España. Institut d’Investigació Biomèdica de Girona; EspañaFil: Vellón, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Chen, Wen Y.. Clemson University; Estados UnidosFil: Lupu, Ruth. Mayo Foundation for Medical Education and Research. Mayo Clinic; Estados Unidos. Clemson University; Estados Unidos. Mayo Clinic Cancer Center; Estados Unido

Characterization of Mycobacterium chelonae-like strains by comparative genomics

Isolates of the Mycobacterium chelonae-M. abscessus complex are subdivided into four clusters (CHI to CHIV) in the INNO-LiPA (R) Mycobacterium spp DNA strip assay. A considerable phenotypic variability was observed among isolates of the CHII cluster. In this study, we examined the diversity of 26 CHII cluster isolates by phenotypic analysis, drug susceptibility testing, whole genome sequencing and single-gene analysis. Pairwise genome comparisons were performed using several approaches, including average nucleotide identity (ANI) and genome-to-genome distance (GGD) among others. Based on ANI and GGD the isolates were identified as M. chelonae (14 isolates), M. franklinii (2 isolates) and M. salmoniphium (1 isolate). The remaining 9 isolates were subdivided into three novel putative genomospecies. Phenotypic analyses including drug susceptibility testing, as well as whole genome comparison by TETRA and delta differences, were not helpful in separating the groups revealed by ANI and GGD. The analysis of standard four conserved genomic regions showed that rpoB alone and the concatenated sequences clearly distinguished the taxonomic groups delimited by whole genome analyses. In conclusion, the CHII INNO-LiPa is not a homogeneous cluster; on the contrary, it is composed of closely related different species belonging to the M. chelonae-M. abscessus complex and also several unidentified isolates. The detection of these isolates, putatively novel species, indicates a wider inner variability than the presently known in this complex

GATA2 Promotes Hematopoietic Development and Represses Cardiac Differentiation of Human Mesoderm.

In vertebrates, GATA2 is a master regulator of hematopoiesis and is expressed throughout embryo development and in adult life. Although the essential role of GATA2 in mouse hematopoiesis is well established, its involvement during early human hematopoietic development is not clear. By combining time-controlled overexpression of GATA2 with genetic knockout experiments, we found that GATA2, at the mesoderm specification stage, promotes the generation of hemogenic endothelial progenitors and their further differentiation to hematopoietic progenitor cells, and negatively regulates cardiac differentiation. Surprisingly, genome-wide transcriptional and chromatin immunoprecipitation analysis showed that GATA2 bound to regulatory regions, and repressed the expression of cardiac development-related genes. Moreover, genes important for hematopoietic differentiation were upregulated by GATA2 in a mostly indirect manner. Collectively, our data reveal a hitherto unrecognized role of GATA2 as a repressor of cardiac fates, and highlight the importance of coordinating the specification and repression of alternative cell fates.Ramón y Cajal Program, Spanish Ministry of Economy, Industry, and Competitiveness, Spanish Cancer Association, FERO, Instituto de Salud Carlos III, European Social Fund, MINECO, PERIS Program of the Generalitat de Catalunya, Obra Social la Caixa-Fundacion Josep Carreras, Spanish Institute of Health Carlos III, Wellcome Trust, MRC, CRUK, NIH-NIDD