Cancer immunotherapy using irradiated tumor cells secreting heat shock protein 70

Ovarian cancer is responsible for the highest mortality rate among patients with gynecologic malignancies. Therefore, there is an emerging need for innovative therapies for the control of advanced ovarian cancer. Immunotherapy has emerged as a potentially plausible approach for the control of ovarian cancer. In the current study, we have generated heat shock protein 70 (Hsp70)-secreting murine ovarian cancer cells that express luciferase (MOSEC/luc). Hsp70 has been shown to target and concentrate antigenic peptides in dendritic cells and is also able to activate dendritic cells. We characterized the antigen-specific immune response and the antitumor effect of the MOSEC/luc cells expressing Hsp70 using noninvasive luminescence images to measure the amount of ovarian tumors in the peritoneal cavity of mice. We found that mice challenged with MOSEC/luc cells expressing Hsp70 generate significant antigen-specific CD8+ T-cell immune responses. Furthermore, we also found that mice vaccinated with irradiated MOSEC/luc cells expressing Hsp70 generate significant therapeutic effect against MOSEC/luc cells. In addition, we have shown that CD8+, natural killer, and CD4+ cells are important for protective antitumor effect generated by irradiated tumor cell-based vaccines expressing Hsp70. Moreover, we also found that CD40 receptor is most important, followed by Toll-like receptor 4 receptor, for inhibiting in vivo tumor growth of the viable MOSEC/luc expressing Hsp70. Thus, the use of Hsp70-secreting ovarian tumor cells represents a potentially effective therapy for the control of lethal ovarian cancer.     

Essential role of the histone lysine demethylase KDM4A in the biology of malignant pleural mesothelioma (MPM)

Background Malignant pleural mesothelioma (MPM) is a highly aggressive cancer with a dismal prognosis. There is increasing interest in targeting chromatin regulatory pathways in difficult-to-treat cancers. In preliminary studies, we found that KDM4A (lysine-specific histone demethylase 4) was overexpressed in MPM.Methods KDM4A protein expression was determined by immunohistochemistry or immunoblotting. Functional inhibition of KDM4A by targeted knockdown and small molecule drugs was correlated to cell growth using cell lines and a xenograft mouse model. Gene expression profiling was performed to identify KDM4A-dependent signature pathways.Results Levels of KDM4A were found to be significantly elevated in MPM patients compared to normal mesothelial tissue. Inhibiting the enzyme activity efficiently reduced cell growth in vitro and reduced tumour growth in vivo. KDM4A inhibitor-induced apoptosis was further enhanced by the BH3 mimetic navitoclax. KDM4A expression was associated with pathways involved in cell growth and DNA repair. Interestingly, inhibitors of the DNA damage and replication checkpoint regulators CHK1 (prexasertib) and WEE1 (adavosertib) within the DNA double-strand break repair pathway, cooperated in the inhibition of cell growth.Conclusions The results establish a novel and essential role for KDM4A in growth in preclinical models of MPM and identify potential therapeutic approaches to target KDM4A-dependent vulnerabilities.Subject terms: Mesothelioma, Biochemistry, Cell biology     

Bench-to-bedside review: Diaphragm muscle function in disuse and acute high-dose corticosteroid treatment

Critically ill patients may require mechanical ventilatory support and short-term high-dose corticosteroid to treat some specific underlying disease processes. Diaphragm muscle inactivity induced by controlled mechanical ventilation produces dramatic alterations in diaphragm muscle structure and significant losses in function. Although the exact mechanisms responsible for losses in diaphragm muscle function are still unknown, recent studies have highlighted the importance of proteolysis and oxidative stress. In experimental animals, short-term strategies that maintain partial diaphragm muscle neuromechanical activation mitigate diaphragmatic force loss. In animal models, studies on the influence of combined controlled mechanical ventilation and short-term high-dose methylprednisolone have given inconsistent results in regard to the effects on diaphragm muscle function. In the critically ill patient, further research is needed to establish the prevalence and mechanisms of ventilator-induced diaphragm muscle dysfunction, and the possible interaction between mechanical ventilation and the administration of high-dose corticosteroid. Until then, in caring for these patients, it is imperative to allow partial activation of the diaphragm, and to administer the lowest dose of corticosteroid for the shortest duration possible.     

Immunoglobulin M and G immunoblots in the diagnosis of parvovirus B19 infection.

BACKGROUND AND PURPOSE: To identify parvovirus B19 infection by means of immunoglobulin (Ig) G and IgM immunoblots among immunocompetent patients who tested negative or had low-titer B19 IgM antibodies in enzyme-linked immunosorbent assays (ELISA). METHODS: Serum samples were obtained from 20 patients with parvovirus B19 infection. Another 130 study subjects presumed to be without B19 infection (40 medical personnel and 90 prisoners) were also included. All sera from the patient and study groups tested positive for IgG or IgM with ELISA and were further evaluated using the immunoblot method. Detection of B19 DNA by nested polymerase chain reaction (PCR) was also performed on IgG and IgM positive sera. RESULTS: IgM immunoblots disclosed one false positive IgM ELISA result in the patient group and three false positive results in the study group. In the patient group, four patients were in the latter stage of antibody response to B19 infection as suggested by the low titer of anti-B19 IgM, incomplete IgM immunoblots, with only a weak viral capsid protein VP-N reaction band, and fading but still strong reaction bands on IgG immunoblots. Strong reaction bands on IgG immunoblots comparable to these four patients were found in three of the 130 study group sera. Furthermore, B19 DNA was detected in three of the four patients and one of the three study subjects by means of nested-PCR. A serum sample from one study subject showed strong IgG but no IgM reactivity to viral capsid protein VP2; nested PCR identified B19 DNA in this serum sample. CONCLUSIONS: Immunoblots and nested PCR should be applied in the diagnosis of B19 infection for patients with low-titer anti-B19 IgM tested by means of ELISA. For diagnosis of B19 infections in certain clinical entities such as chronic arthritis of recent onset and hydrops fetalis, B19 IgM antibodies may have disappeared but B19 infection can still be recognized by the intensity of the reaction bands on IgG immunoblots. The correlation between chronic B19 infection and persistence of antilinear VP2 epitopes requires further study.