Constitutively Activated PI3K Accelerates Tumor Initiation and Modifies Histopathology of Breast Cancer

The gene encoding phosphatidylinositol 3-kinase catalytic subunit α-isoform (PIK3CA, p110α) is frequently activated by mutation in human cancers. Based on detection in some breast cancer precursors, PIK3CA mutations have been proposed to have a role in tumor initiation. To investigate this hypothesis, we generated a novel mouse model with a Cre-recombinase regulated allele of p110α (myristoylated-p110α, myr-p110α) along with p53fl/fl deletion and KrasG12D also regulated by Cre-recombinase. After instillation of adenovirus-expressing Cre-recombinase into mammary ducts, we found that myr-p110α accelerated breast tumor initiation in a copy number-dependent manner. Breast tumors induced by p53fl/fl;KrasG12D with no or one copy of myr-p110α had predominantly sarcomatoid features, whereas two copies of myr-p110α resulted in tumors with a carcinoma phenotype. This novel model provides experimental support for importance of active p110α in breast tumor initiation, and shows that the amount of PI3K activity can affect the rate of tumor initiation and modify the histological phenotype of breast cancer

Satb1 overexpression drives tumor-promoting activities in cancer-associated dendritic cells

Special AT-rich sequence-binding protein 1 (Satb1) governs genome-wide transcriptional programs. Using a conditional knockout mouse, we find that Satb1 is required for normal differentiation of conventional dendritic cells (DCs). Furthermore, Satb1 governs the differentiation of inflammatory DCs by regulating major histocompatibility complex class II (MHC II) expression through Notch1 signaling. Mechanistically, Satb1 binds to the Notch1 promoter, activating Notch expression and driving RBPJ occupancy of the H2-Ab1 promoter, which activates MHC II transcription. However, tumor-driven, unremitting expression of Satb1 in activated Zbtb46(+) inflammatory DCs that infiltrate ovarian tumors results in an immunosuppressive phenotype characterized by increased secretion of tumor-promoting Galectin-1 and IL-6. In vivo silencing of Satb1 in tumor-associated DCs reverses their tumorigenic activity and boosts protective immunity. Therefore, dynamic fluctuations in Satb1 expression govern the generation and immunostimulatory activity of steady-state and inflammatory DCs, but continuous Satb1 overexpression in differentiated DCs converts them into tolerogenic/pro-inflammatory cells that contribute to malignant progression.Fil: Tesone, Amelia J.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Rutkowski, Melanie R.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Brencicova, Eva. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Svoronos, Nikolaos. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Perales Puchal, Alfredo. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Stephen, Tom L.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Allegrezza, Michael J.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Payne, Kyle K.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Nguyen, Jenny M.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados UnidosFil: Wickramasinghe, Jayamanna. The Wistar Institute. Center for Systems and Computational Biology; Estados UnidosFil: Tchou, Julia. University of Pennsylvania; Estados UnidosFil: Borowsky, Mark E.. Christiana Care Health System. Helen F. Graham Cancer Center; Estados UnidosFil: Rabinovich, Gabriel Adrián. 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: Kossenkov, Andrew V.. The Wistar Institute. Center for Systems and Computational Biology; Estados UnidosFil: Conejo Garcia, José R.. The Wistar Institute. Tumor Microenvironment and Metastasis Program; Estados Unido

Identifying alemtuzumab as an anti-myeloid cell antiangiogenic therapy for the treatment of ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Murine studies suggest that myeloid cells such as vascular leukocytes (VLC) and Tie2⁺monocytes play a critical role in tumor angiogenesis and vasculogenesis. Myeloid cells are a primary cause of resistance to anti-VEGF therapy. The elimination of these cells from the tumor microenvironment significantly restricts tumor growth in both spontaneous and xenograft murine tumor models. Thus animal studies indicate that myeloid cells are potential therapeutic targets for solid tumor therapy. Abundant VLC and Tie2⁺monocytes have been reported in human cancer. Unfortunately, the importance of VLC in human cancer growth remains untested as there are no confirmed therapeutics to target human VLC.</p> <p>Methods</p> <p>We used FACS to analyze VLC in ovarian and non-ovarian tumors, and characterize the relationship of VLC and Tie2-monocytes. We performed qRT-PCR and FACS on human VLC to assess the expression of the CD52 antigen, the target of the immunotherapeutic Alemtuzumab. We assessed Alemtuzumab's ability to induce complement-mediated VLC killing in vitro and in human tumor ascites. Finally we assessed the impact of anti-CD52 immuno-toxin therapy on murine ovarian tumor growth.</p> <p>Results</p> <p>Human VLC are present in ovarian and non-ovarian tumors. The majority of VLC appear to be Tie2+ monocytes. VLC and Tie2+ monocytes express high levels of CD52, the target of the immunotherapeutic Alemtuzumab. Alemtuzumab potently induces complement-mediated lysis of VLC in vitro and ex-vivo in ovarian tumor ascites. Anti-CD52 immunotherapy targeting VLC restricts tumor angiogenesis and growth in murine ovarian cancer.</p> <p>Conclusion</p> <p>These studies confirm VLC/myeloid cells as therapeutic targets in ovarian cancer. Our data provide critical pre-clinical evidence supporting the use of Alemtuzumab in clinical trials to test its efficacy as an anti-myeloid cell antiangiogenic therapeutic in ovarian cancer. The identification of an FDA approved anti-VLC agent with a history of clinical use will allow immediate proof-of-principle clinical trials in patients with ovarian cancer.</p

The role of dendritic cell precursors in tumour vasculogenesis

In this review, we discuss the recent identification in vivo of a population of CD11c+ cells exhibiting simultaneous expression of both endothelial and dendritic cell markers, termed vascular leukocytes (VLCs). VLCs are highly represented in human ovarian carcinomas and, depending on the milieu, can assemble into functional blood vessels or act as antigen-presenting cells. The identification of dendritic cell precursors as bipotent cells has important implications for the physiopathology and therapy of tumours. VLCs emerge as a novel therapeutic target against tumour vascularisation

A randomized phase II trial of platinum salts in basal-like breast cancer patients in the neoadjuvant setting. Results from the GEICAM/2006-03, multicenter study

Este artículo ha sido publicado en Breast Cancer Research and Treatment Siguiendo las instruciones y dado que la revista dice que el artículo fue publicado tal cual se envió, hacemos un postprint copiando dicho texto enviado por la revista en un documento Word y luego convertido a PDF para así respetar el contenido, y sin dar acceso a los "extras" de la versión publicada. Esta versión tiene Licencia Creative Commons CC-BY-NC-NDAbstract Chemotherapy remains as the only systemic treatment option available for basal-like breast cancer (BC) patients. Preclinical models and several phase II studies suggested that platinum salts are active drugs in this BC subtype though there is no randomized study supporting this hypothesis. This study investigates if the addition of carboplatin to a combination of an alkylating agent together with anthracyclines and taxanes is able to increase the efficacy in the neoadjuvant treatment context. Patients with operable breast cancer and immunophenotypically defined basal-like disease (ER-/PR-/HER2- and cytokeratin 5/6? or EGFR?) were recruited. Patients were randomized to receive EC (epirubicin 90 mg/m2 plus cyclophosphamide 600 mg/m2 for 4 cycles) followed either by D (docetaxel 100 mg/m2 9 4 cycles; EC–D) or DCb (docetaxel 75 mg/ m2 plus carboplatin AUC 6 9 4 cycles; EC–DCb). The primary end point was pathological complete response (pCR) in the breast following the Miller and Payne criteria. Ninety-four patients were randomized (46 EC–D, 48 EC– DCb). pCR rate in the breast was seen in 16 patients (35 %) with EC–D and 14 patients (30 %) with EC–DCb (P value = 0.61). pCR in the breast and axilla was seen in 30 % of patients in both arms. The overall clinical response rate was 70 % (95 % CI 56–83) in the EC–D arm and 77 % (95 % CI 65–87) in the EC–DCb arm. Grade 3/4 toxicity was similar in both arms. The addition of carboplatin to conventional chemotherapy with EC–D in basal-like breast cancer patients did not improve the efficacy probably because they had already received an alkylating agent. These findings should be taken into consideration when developing new agents for this disease.This trial was partially supported by Pfizer S.L.U

IRE1α–XBP1 controls T cell function in ovarian cancer by regulating mitochondrial activity

Tumours evade immune control by creating hostile microenvironments that perturb T cell metabolism and effector function 1?4 . However, it remains unclear how intra-tumoral T cells integrate and interpret metabolic stress signals. Here we report that ovarian cancer?an aggressive malignancy that is refractory to standard treatments and current immunotherapies 5?8 ?induces endoplasmic reticulum stress and activates the IRE1α?XBP1 arm of the unfolded protein response 9,10 in T cells to control their mitochondrial respiration and anti-tumour function. In T cells isolated from specimens collected from patients with ovarian cancer, upregulation of XBP1 was associated with decreased infiltration of T cells into tumours and with reduced IFNG mRNA expression. Malignant ascites fluid obtained from patients with ovarian cancer inhibited glucose uptake and caused N-linked protein glycosylation defects in T cells, which triggered IRE1α?XBP1 activation that suppressed mitochondrial activity and IFNγ production. Mechanistically, induction of XBP1 regulated the abundance of glutamine carriers and thus limited the influx of glutamine that is necessary to sustain mitochondrial respiration in T cells under glucose-deprived conditions. Restoring N-linked protein glycosylation, abrogating IRE1α?XBP1 activation or enforcing expression of glutamine transporters enhanced mitochondrial respiration in human T cells exposed to ovarian cancer ascites. XBP1-deficient T cells in the metastatic ovarian cancer milieu exhibited global transcriptional reprogramming and improved effector capacity. Accordingly, mice that bear ovarian cancer and lack XBP1 selectively in T cells demonstrate superior anti-tumour immunity, delayed malignant progression and increased overall survival. Controlling endoplasmic reticulum stress or targeting IRE1α?XBP1 signalling may help to restore the metabolic fitness and anti-tumour capacity of T cells in cancer hosts.Fil: Song, Minkyung. Weill Cornell Medicine; Estados UnidosFil: Sandoval, Tito A.. Weill Cornell Medicine; Estados UnidosFil: Chae, Chang-Suk. Weill Cornell Medicine; Estados UnidosFil: Chopra, Sahil. Weill Cornell Medicine; Estados UnidosFil: Tan, Chen. Weill Cornell Medicine; Estados UnidosFil: Rutkowski, Melanie R.. University of Virginia; Estados UnidosFil: Raundhal, Mahesh. Dana Farber Cancer Institute; Estados Unidos. Harvard Medical School; Estados UnidosFil: Chaurio, Ricardo A.. H. Lee Moffitt Cancer Center & Research Institute; Estados UnidosFil: Payne, Kyle K.. H. Lee Moffitt Cancer Center & Research Institute; Estados UnidosFil: Konrad, Csaba. Weill Cornell Medicine; Estados UnidosFil: Bettigole, Sarah E.. Quentis Therapeutics Inc.; Estados UnidosFil: Shin, Hee Rae. Quentis Therapeutics Inc.; Estados UnidosFil: Crowley, Michael J. P.. Weill Cornell Graduate School of Medical Sciences; Estados UnidosFil: Cerliani, Juan Pablo. 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: Kossenkov, Andrew V.. The Wistar Institute; Estados UnidosFil: Motorykin, Ievgen. Weill Cornell Medicine,; Estados UnidosFil: Zhang, Sheng. Weill Cornell Medicine,; Estados UnidosFil: Manfredi, Giovanni. Weill Cornell Medicine,; Estados UnidosFil: Zamarin, Dmitriy. Memorial Sloan Kettering Cancer Center; Estados UnidosFil: Holcomb, Kevin. Weill Cornell Medicine,; Estados UnidosFil: Rodriguez, Paulo C.. H. Lee Moffitt Cancer Center & Research Institute; Estados UnidosFil: Rabinovich, Gabriel Adrián. 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; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Conejo Garcia, Jose R.. H. Lee Moffitt Cancer Center & Research Institute; Estados UnidosFil: Glimcher, Laurie H.. Dana Farber Cancer Institute; Estados Unidos. Harvard Medical School; Estados UnidosFil: Cubillos-Ruiz, Juan R.. Weill Graduate School Of Medical Sciences; Estados Unidos. Weill Graduate School Of Medical Sciences; Estados Unido

X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients

Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern

Anti-angiogenic effect of high doses of ascorbic acid

Pharmaceutical doses of ascorbic acid (AA, vitamin C, or its salts) have been reported to exert anticancer activity in vitro and in vivo. One proposed mechanism involves direct cytotoxicity mediated by accumulation of ascorbic acid radicals and hydrogen peroxide in the extracellular environment of tumor cells. However, therapeutic effects have been reported at concentrations insufficient to induce direct tumor cell death. We hypothesized that AA may exert anti-angiogenic effects. To test this, we expanded endothelial progenitor cells (EPCs) from peripheral blood and assessed, whether or not high dose AA would inhibit EPC ability to migrate, change energy metabolism, and tube formation ability. We also evaluated the effects of high dose AA on angiogenic activities of HUVECs (human umbilical vein endothelial cells) and HUAECs (human umbilical arterial endothelial cells). According to our data, concentrations of AA higher than 100 mg/dl suppressed capillary-like tube formation on Matrigel for all cells tested and the effect was more pronounced for progenitor cells in comparison with mature cells. Co-culture of differentiated endothelial cells with progenitor cells showed that there was incorporation of EPCs in vessels formed by HUVECs and HUAECs. Cell migration was assessed using an in vitro wound healing model. The results of these experiments showed an inverse correlation between AA concentrations relative to both cell migration and gap filling capacity. Suppression of NO (nitric oxide) generation appeared to be one of the mechanisms by which AA mediated angiostatic effects. This study supports further investigation into non-cytotoxic antitumor activities of AA

Mycobacterium tuberculosis infection induces il12rb1 splicing to generate a novel IL-12Rβ1 isoform that enhances DC migration

RNA splicing is an increasingly recognized regulator of immunity. Here, we demonstrate that after Mycobacterium tuberculosis infection (mRNA) il12rb1 is spliced by dendritic cells (DCs) to form an alternative (mRNA) il12rb1Deltatm that encodes the protein IL-12Rbeta1DeltaTM. Compared with IL-12Rbeta1, IL-12Rbeta1DeltaTM contains an altered C-terminal sequence and lacks a transmembrane domain. Expression of IL-12Rbeta1DeltaTM occurs in CD11c(+) cells in the lungs during M. tuberculosis infection. Selective reconstitution of il12rb1(-/-) DCs with (mRNA) il12rb1 and/or (mRNA) il12rb1Deltatm demonstrates that IL-12Rbeta1DeltaTM augments IL-12Rbeta1-dependent DC migration and activation of M. tuberculosis-specific T cells. It cannot mediate these activities independently of IL12Rbeta1. We hypothesize that M. tuberculosis-exposed DCs express IL-12Rbeta1DeltaTM to enhance IL-12Rbeta1-dependent migration and promote M. tuberculosis-specific T cell activation. IL-12Rbeta1DeltaTM thus represents a novel positive-regulator of IL12Rbeta1-dependent DC function and of the immune response to M. tuberculosis.This work was supported by the Trudeau Institute and the National Institutes of Health (AI067723 to A. M. Cooper; AI49823 to D. L. Woodland [trainee: R. T. Robinson] and AI084397 to R. T. Robinson)