Latin America multidisciplinary research on heat shock proteins and cell stress: proceedings of the first conference of the Latin America Chapter of the Cell Stress Society International.

The First Conference of the Latin America Chapter of the Cell Stress Society International (CSSI) organized by CSSI was held in Montevideo, Uruguay, on March 11-14, 2014. The Latin America Chapter of the CSSI (LAC-CSSI) was established at the Workshop on the Molecular Biology of the Stress Response, Porto Alegre, Brazil, May 2012. The chapter's first meeting took place in the beautiful city of Montevideo and was chaired by the first (LAC-CSSI) elected president Professor María Bausero.

Silencing Hsp25/Hsp27 gene expression augments proteasome activity and increases CD8+ T-cell-mediated tumor killing and memory responses.

Relatively high expression of Hsp27 in breast and prostate cancer is a predictor of poor clinical outcome. This study elucidates a hitherto unknown mechanism by which Hsp27 regulates proteasome function and modulates tumor-specific T-cell responses. Here, we showed that short-term silencing of Hsp25 or Hsp27 using siRNA or permanent silencing of Hsp25 using lentivirus RNA interference technology enhanced PA28α mRNA expression, PA28α protein expression, and proteasome activity; abrogated metastatic potential; induced the regression of established breast tumors by tumor-specific CD8(+) T cells; and stimulated long-lasting memory responses.

Radiation therapy induces circulating serum Hsp72 in patients with prostate cancer.

Background And Purpose: Hsp72 found in the extracellular milieu has been shown to play an important role in immune regulation. The impact of common cancer therapies on extracellular release of Hsp72 however, has been to date undefined.

Materials And Methods: Serum from 13 patients undergoing radiation therapy (XRT) for prostate cancer with or without hormonal therapy (ADT) was measured for levels of circulating serum Hsp72 and pro-inflammatory cytokines (IL-6 and TNF-alpha) using the classical sandwich ELISA technique and the relative expression of CD8(+) T lymphocytes and natural killer (NK) cells was measured using flow cytometry.

P-cadherin and beta-catenin are useful prognostic markers in breast cancer patients; beta-catenin interacts with heat shock protein Hsp27.

The cadherin-catenin proteins have in common with heat shock proteins (HSP) the capacity to bind/interact proteins of other classes. Moreover, there are common molecular pathways that connect the HSP response and the cadherin-catenin protein system. In the present study, we have explored whether in breast cancer the HSP might interact functionally with the cadherin-catenin cell adhesion system.

Silencing the hsp25 gene eliminates migration capability of the highly metastatic murine 4T1 breast adenocarcinoma cell.

The 25-kDa heat shock protein (Hsp25) is associated with various malignancies and is expressed at high levels in biopsies as well as circulating in the serum of breast cancer patients. In this study, we used RNA interference technology to silence the hsp25 gene in 4T1 breast adenocarcinoma cells, known as a poorly immunogenic, highly metastatic cell line. We demonstrate that transfection of 4T1 cells with short interference RNA-Hsp25 dramatically inhibits proliferation as compared with control transfected cells.

Alternative mechanism by which IFN-gamma enhances tumor recognition: active release of heat shock protein 72.

IFN-gamma exhibits differential effects depending on the target and can induce cellular activation and enhance survival or mediate cell death via activation of apoptotic pathways. In this study, we demonstrate an alternative mechanism by which IFN-gamma enhances tumor recognition, mediated by the active release of Hsp72. We demonstrate that stimulation of 4T1 breast adenocarcinoma cells and K562 erythroleukemic cells with IFN-gamma triggers the cellular stress response, which results in the enhanced expression of total Hsp72 expression without a significant increase in cell death.

Major role of HSP70 as a paracrine inducer of cytokine production in human oxidized LDL treated macrophages.

Lipid accumulation and inflammation are key hallmarks of the atherosclerotic plaque and macrophage uptake of oxidized low-density lipoprotein (oxLDL) is believed to drive these processes. Initial experiments show that supernatants from oxLDL treated macrophages could induce IL-1beta production in naïve macrophages. To search for potential paracrine mediators that could mediate this effect a DNA microarray scan of oxLDL treated human macrophages was performed.

Heat shock protein 70 surface-positive tumor exosomes stimulate migratory and cytolytic activity of natural killer cells.

Detergent-soluble membrane vesicles are actively released by human pancreas (Colo-/Colo+) and colon (CX-/CX+) carcinoma sublines, differing in their capacity to present heat shock protein 70 (Hsp70)/Bag-4 on their plasma membranes. Floating properties, acetylcholine esterase activity, and protein composition characterized them as exosomes. An enrichment of Rab-4 documented their intracellular transport route from early endosomes to the plasma membrane.

Sickle cell vaso-occlusive crisis induces the release of circulating serum heat shock protein-70.

Inflammation may play an important role in the pathophysiology of sickle cell disease (SCD), and recent studies have identified the 70-kDa heat shock protein (Hsp70) as an important mediator of inflammatory responses. Here we demonstrate a significant increase in circulating serum Hsp70 level in SCD during vaso-occlusive crisis (VOC) as compared with baseline steady-state levels (P <0.05) and a significant increase in Hsp70 levels in SCD at baseline compared with normal controls (P <0.

Surface expression of Hsp25 and Hsp72 differentially regulates tumor growth and metastasis.

The expression of unique surface structures on tumors that allow for recognition and activation of host immunocompetent cells plays an important role in determining tumor growth and/or metastasis. Recent studies have identified an important role for heat shock proteins (Hsp) in antitumor surveillance; however, the exact role of Hsp expressed on the surface of tumors has not been fully addressed. In this study, we show that 4T1 mammary adenocarcinoma cells sorted for high Hsp25 surface expression (Hsp25(high)) grow significantly faster than cells sorted for intermediate Hsp25 surface expression (Hsp25(intermediate)) or wild-type 4T1 cells implanted into the abdominal breast gland of female BALB/c mice (p < 0.

Cardiovascular disease delay in centenarian offspring: role of heat shock proteins.

Cardiovascular disease is a major cause of morbidity and mortality of older Americans. We have demonstrated recently that centenarian offspring, when compared with age-matched controls, avoid and/or delay cardiovascular disease and cardiovascular risk factors. Given recent evidence suggesting that higher circulating levels of HSP70 predict the future development of cardiovascular disease in established hypertensives and a recent study demonstrating a decrease in HSP60 and HSP70 with advancing age, we hypothesized that HSP70 levels would be lower in centenarian offspring compared with controls.

Immunobiological characterization of N -nitrosomethylurea-induced rat breast carcinomas: tumoral IL-10 expression as a possible immune escape mechanism.

Improvement of immunotherapy-based protocols in cancer requires a better understanding of tumor microenvironment and tumor-host interaction. Stromal and immune cells and molecules such as cytokines, chemokines, growth factors and metalloproteases mediate tumor-host interaction determining, at least in part, tumor development. In the present study, we used an immunohistochemical approach to explore leukocyte sub-populations, cytokine profiles and costimulatory molecule expression in rat N -Nitrosomethylurea (NMU)-induced breast tumors.

Effective immunization against neuroblastoma using double-transduced tumor cells secreting GM-CSF and interferon-gamma.

Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector MFG-granulocyte-macrophage colony-stimulating factor (GM-CSF), to examine immune stimulation conferred by localized GM-CSF production. Expression of murine GM-CSF by neuro-2a (N-2a/GM) significantly reduced its tumorigenicity. Moreover, immunization of mice with irradiated N-2a/GM cells resulted in a significant protective effect against live tumor challenge 14 days later.

Irradiation of singly and doubly transduced murine neuroblastoma cells expressing B7-1 and producing interferon-gamma reduces their capacity to induce systemic immunity.

We have previously reported that immunization with low major histocompatibility complex (MHC) class I expressing murine neuroblastoma (neuro-2a) transduced with B7-1 fails to induce significant protection to wild-type tumor challenge. In this study we investigated whether B7-1 expressing neuro-2a cells can stimulate an effective T-cell response if they were cotransduced with the interferon-gamma (IFN-gamma) gene to upregulate MHC class I. Transfer of both the IFN-gamma and B7-1 genes into neuro-2a (N-2a/B7-1/IFN) almost completely abrogated the tumorigenic potential of this tumor and improved survival when compared with mice receiving the single transductants, N-2a/IFN and N-2a/B7-1.

B7-1 expression decreases tumorigenicity and induces partial systemic immunity to murine neuroblastoma deficient in major histocompatibility complex and costimulatory molecules.

Neuroblastoma may escape an immune attack by virtue of its low expression of surface accessory molecules essential in the antitumor response. Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector LB7-1SN to examine the influence of B7-1 expression on the immune response directed against a low major histocompatibility class (MHC) I and class II negative, B7-2, and ICAM-1 negative tumor. Using a retroperitoneal model for implantation of neuroblastoma in its natural site, we demonstrated that expression of B7-1 by neuro-2a reduces its tumorigenicity.

Short-term ex vivo activation of splenocytes with anti-CD3 plus IL-2 and infusion post-BMT into mice results in in vivo expansion of effector cells with potent anti-lymphoma activity.

We investigated the proliferation and therapeutic utility of anti-CD3 activated splenocytes infused into mice following BMT. Using congenic mouse strains we demonstrated that splenocytes activated briefly ex vivo with anti-CD3 plus IL-2 (T-activated killer cells or T-AK) and infused intravenously following BMT had a greater expansion in blood, spleen and BM compared with splenocytes stimulated with IL-2 alone. T-AK cells recovered from blood, spleen and BM consisted predominantly of CD8+ T cells.

Retroperitoneal inoculation of murine neuroblastoma results in a reliable model for evaluation of the antitumor immune response.

To more closely mimic the natural site of human neuroblastoma and the original spontaneous arising paraspinal murine tumor, the authors developed a new model system in which murine neuroblastoma cells (neuro-2a) are implanted directly into the retroperitoneal space. This method of administration resulted in an aggressive and reproducible neuroblastoma model, with death occurring at a median of 20.3 days after tumor implantation using 1 x 10(6) neuro-2a cells, compared with the intraperitoneal (median, 31 days) and subcutaneous routes (median, 35.

Interleukin-2 gene transfer into murine neuroblastoma decreases tumorigenicity and enhances systemic immunity causing regression of preestablished retroperitoneal tumors.

Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector LIL-2SN in order to examine the influence of localized interleukin (IL)-2 production on the immune response against a low major histocompatibility complex (MHC) class I, class II-negative, and intercellular adhesion molecule (ICAM)-1-negative tumor. Two neomycin-resistant (neo R) clones, N-2a/IL-2/L (2.5 +/- 0.

Transfection of the mouse ICAM-1 gene into murine neuroblastoma enhances susceptibility to lysis, reduces in vivo tumorigenicity and decreases ICAM-2-dependent killing.

We determined the expression of intercellular adhesion molecules (ICAM) on neuro-2a cells in order to evaluate whether they were involved in cytolysis of murine neuroblastoma. Fluorescence-activated cell sorting analysis revealed that the control neomycin-resistance-gene-transduced line (neuro-2a/LN) had poor expression of ICAM-1 (mean channel fluorescence, MCF = 3.7).

Importance in timing of cyclophosphamide on the enhancement of interleukin-2-induced cytolysis.

We investigated the in vivo effects of cyclophosphamide (CY) on interleukin-2(IL-2)-induced cytolytic function and spleen cell immunophenotype. Pretreatment of A/J mice with CY (25 mg/kg or 75 mg/kg) i.p.