Heat shock proteins in cancer therapy

Expression Profiling of Hspb1 and Tp53 Genes through RT-qPCR in Different Cancer Types of Canis familiaris

Background: Diagnostic molecular marker studies are in vogue to have insight of most prevalent animal diseases including cancer. Objectives: Gene expression profiling of pro and anti-apoptotic genes was conducted in dog Lymphoma, CTVT, SCC, granuloma, perianal adenocarcinoma and mammary tumors. Materials and Methods: Cancerous tissues of 21 affected animals were obtained. Total RNA was extracted followed by cDNA synthesis. Comparative Ct method via Taqman assay (RT-qPCR) was used to quantify corresponding mRNA molecules, Tp53 and Hspb1, as normalized by GAPDH as the reference gene . Results:Hspb1 showed ectopic expression in lymphoma, CTVT and mammary tumors; its down-regulation was observed in granuloma and oral SCC with fold difference (FD) of ±35. Similarly, Tp53 as the tumor suppressor gene with pro-apoptotic properties, showed up-regulation in all tumor types, notably 80% of mammary tumors and 60% of CTVT. The FD values were 33.31 and 2.27, respectively. Conclusion: Altered transcriptomic response of Hspb1 and Tp53 was observed in all cancer types of Canis familiaris. The resulting profile depicts the involvement of the genes in cancer pathways. Thus, the data might be helpful for diagnosis, prognosis, identification and classification of these widespread neoplasms in this species.

Heat shock does not induce γH2AX foci formation but protects cells from N-methyl-N′-nitro-N-nitrosoguanidine-induced genotoxicity

The involvement of DNA damage in heat shock-induced cell death remains controversial. To investigate whether heat shock can induce DNA damage, we tested the induction of gammaH2AX foci formation, a sensitive indicator for DNA double strand breaks (DSBs), by heat shock treatment in several cell lines including HeLa, CHL, HepG2, and 293 cells, as well as human spermatozoa. Although heat shock treatment can decrease cell viability, no induction of gammaH2AX foci formation was observed in any of these cells. In addition, a p53-deficient cell line (U2OSE6tet24) and a flap endonuclease 1 (FEN1)-deficient cell line (FL-FEN1(-)) also did not show induction of gammaH2AX foci after heat shock treatment. Finally, it was found that 30min of pre-heat shock can inhibit gammaH2AX foci formation induced by an alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which is known to induce gammaH2AX foci formation. On the other hand, heat shock after MNNG treatment did not affect the gammaH2AX foci formation induced by MNNG. Taken together, these data suggest that although heat shock might influence the gammaH2AX foci formation process, it does not induce DNA damage in the cells tested in this study.

New approaches for mesothelioma: biologics, vaccines, gene therapy, and other novel agents

Although malignant mesothelioma is not a classically immunogenic cancer, there is abundant evidence for immune recognition. The relative ease of obtaining tumor tissue makes mesothelioma ideal for studying surrogate biomarkers such as lymphocytic infiltration or expression of transduced genes. There is evidence that malignant mesothelioma patients as well as asbestos-exposed persons without mesothelioma have impaired immune responsiveness. Substantial progress has been made in animal models using several biological and immunological techniques, but clinical application has been problematic. Systems studied have included lysis by interleukin-2 (IL-2)-activated lymphokine-activated killer (LAK) cells, tumor necrosis factor-alpha (TNF-alpha), a p16-expressing adenovirus vector, suicide gene therapy using the herpes simplex virus-tyrosine kinase (HSV-tk) followed by ganciclovir, and immunomodulatory gene therapy with IL-2, IL-4, interferon-gamma (IFN-gamma), IFN-alpha, TNF-alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, and IL-1beta transfected into tumors. Vaccinia virus has been studied as a vector for cytokine gene transfer. Suicide gene therapy has been combined with a tumor vaccine. The University of Western Australia is initiating a pilot study of autologous vaccination in malignant mesothelioma. Novel agents under study include the angiogenesis inhibitors SU5416, bevacizumab, and thalidomide. ZD1839, an orally administered, highly selective inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, is being tested in a phase II trial. Since platelet-derived growth factor (PDGF) is thought to be an autocrine growth factor for mesothelioma STI-571 (Gleevec; Novartis, Basel, Switzerland), a highly selective inhibitor of the PDGF receptor tyrosine kinase, is being tested in a phase II trial. The development of more active cytotoxic combinations in this disease should facilitate further studies of chemoimmunotherapy. It seems likely that no single treatment modality will be effective by itself.