Suppression of metastatic hemangiosarcoma by a parvovirus MVMp vector transducing the IP-10 chemokine into immunocompetent mice

We have previously shown that the growth of human tumor xenografts in immunodeficient mice can be efficiently suppressed upon infection with the autonomous parvovirus H-1 or with cytokine-transducing derivatives thereof. To further evaluate the benefits of implementing parvoviruses in cancer gene therapy, we have created a new recombinant vector, MVMp/IP-10, transducing the immunoactive, antiangiogenic chemokine IP-10, and used this virus to treat syngeneic tumors grown in immunocompetent mice. Intratumoral/intraperitoneal administration of only 3 x 10(7) replication units of MVMp/IP-10 per animal strongly inhibited the progression of established H5V cell-induced vascular tumors, a highly malignant mouse model for human cavernous hemangioma and Kaposi's sarcoma. Retardation of recurrent tumor growth and suppression of life-threatening metastatic dissemination to internal organs were accompanied by a striking delay in hemangioma-associated mortality. Parental MVMp did not have a significant effect under these conditions up to the dose of 10(10) infectious units/animal, but had strong antihemangiosarcoma activity when used to infect H5V cells ex vivo prior to implantation. In all cases, virus therapy was very well tolerated. Virus-induced suppression of hemangiosarcoma was dependent on host T cells and associated with intratumoral persistence of IFN gamma-expressing cytotoxic lymphocytes, and led to the reduced expression of hepatic plasminogen activator inhibitor-1 (PAI-1), a metastasis-linked marker. This proof of principle study demonstrates that MVMp/IP-10 can aid the treatment of vascular tumors and that autonomous parvovirus-based vectors can be considered potent tools for cancer gene therapy purposes.     

The possible role of fungal infections in AIDS

The acquired immunodefficiency syndrome (AIDS) is characterized by a gross defect in the cell-mediated immune response. However, infection with human immunodeficiency virus (HIV), which is the generally accepted etiological factor of AIDS, cannot explain by itself the following problems: why do not some of the seropositive subjects develop AIDS or AIDS-related complex; why are some of the patients with AIDS seronegative for HIV and its corresponding antibodies; what is the reason why some of the healthy seronegative subjects from groups at a high risk for AIDS (homosexuals, hemophiliacs and drug abusers) have low T-helper to T-suppressor ratios. We suggest that some additional factor is necessary for the development of AIDS. We propose that the factor needed is a 'partial functional thymectomy'. We suspect that slow fungal infections, producing thymotoxic metabolites, may be a major cause for the latter.     

Immune cells participate in the oncosuppressive activity of parvovirus H-1PV and are activated as a result of their abortive infection with this agent

Treatment of cancers by means of viruses, that specifically replicate in (oncotropism) and kill (oncolysis) neoplastic cells, is increasingly gaining acceptance in the clinic. Among these agents, parvoviruses have been shown to possess not only direct oncolytic but also immunomodulating properties, serving as an adjuvant to prime the immune system to react against infected tumors. Here, we aimed to establish whether immunomodulating mechanisms participate in the recently reported therapeutic potential of parvoviruses against pancreatic carcinoma. Using adoptive transfer experiments we discovered that the transfer of splenocytes of donor rats harboring H-1PV-treated orthotopic PDAC tumors could significantly prolong the survival of na?ve tumor-bearing recipients, compared to those receiving cells from mock-treated donors. Closer investigation of immunological parameters in infected donor rats revealed that virus-induced interferon gamma production and cellular immune response played an important role in this effect. These data have also preclinical relevance since abortive H-1PV infection of human peripheral blood mononuclear cells or cocultivation of these cells with H-1PV-preinfected pancreatic cancer cells, resulted in enhancement of innate and adaptive immune reactivity. Taken together our data reveal that oncolytic H-1PV modulates the immune system into an anticancer state, and further support the concept of using parvoviruses in the fight against pancreatic cancer.     

Potential of tumour cells for delivering oncolytic viruses

Autologous or allogenic tumour cells have long been used in the fight against cancer as vaccines to awaken the patient's immune system. On the other hand, oncolytic viruses have emerged in recent years as powerful therapeutic tools for selectively killing tumour cells. Yet despite recent improvements in virus production, administration and targeting, the latter strategy remains limited by poor access of oncolytic viruses to primary and metastatic tumour cells. The present review focuses on how to overcome these limitations on oncolytic virus delivery, at least in part, through the use of tumour-derived or in vitro transformed carrier cells. On the basis of existing evidence, novel strategies are proposed for using such cell vehicles, alone or in combination, both as virus factories and as anticancer vaccines.     

Spin-labeled rifamycin: biological activity

3-[(2,2,6,6-Tetramethylpiperidine-4-ylimino)methyl]rifamycin (4) and spin-labeled rifamycin-3-[(2,2,6,6- tetramethyl-1-oxyl-piperidine-4-ylimino)methyl]rifamycin (1) were prepared. The structures of these compounds were determined by IR, UV, MS and 1H NMR of 4. The ESR-spectrum of 1 is a symmetric triplet signal, characteristic of nitroxyl radicals, g = 2.0025. An in vitro comparative study of the cytotoxicity and antitumor activity of 1, 4 and the initial 3-formyl-rifamycin was carried out in concentrations from 0.1 to 0.001 mM on cells before and after oxidative stress (preliminary irradiation 7Gy) on MH3924A-hepatoma rat cells, 293 transformed human fibroblasts, NBK transformed human fibroblasts and HT 1080 human fibrosarcoma. The compounds showed a cytostatic effect to 85%, with 1 being less toxic in the hepatoma cell line. In human melanoma cell lines 1 showed a higher toxicity than 4. All the derivatives (1 and 4) have in vitro antibacterial activity comparable with that of rifampicin.     

Activation of a glioma-specific immune response by oncolytic parvovirus Minute Virus of Mice infection

Rodent autonomous parvoviruses (PVs) are endowed with oncotropic properties and represent virotherapeutics with inherent oncolytic features. This work aimed to evaluate the capacity of Minute Virus of Mice (MVMp) to act as an adjuvant stimulating a mouse glioblastoma-specific immune response. MVMp was shown to induce cell death through apoptosis in glioma GL261 cells. Antigen-presenting cells (APCs) provide the initial cue for innate and adaptive immune responses, and thus MVMp-infected GL261 cells were tested for their ability to activate dendritic cells (DCs) and microglia (MG), two distinct cell types that are able to act as APCs. MG and discrete DC subsets were activated after co-culture with MVMp-infected glioma GL261 cells, as evidenced by upregulation of specific activation markers (CD80, CD86) and release of proinflammatory cytokines (tumor necrosis factor-α and interleukin-6). The in vivo analysis of immunodeficient and immunocompetent mice revealed a clear difference in their susceptibility to MVMp-mediated tumor suppression. Immunocompetent mice were fully protected from tumor outgrowth of GL261 cells infected ex vivo with MVMp. In contrast, immunodeficient animals were less competent for MVMp-dependent tumor inhibition, with only 20% of the recipients being protected, arguing for an additional immune component to allow full tumor suppression. In keeping with this conclusion, immunocompetent mice engrafted with MVMp-infected glioma cells developed a level of anti-tumor immunity with isolated splenocytes producing elevated levels of interferon-γ. In rechallenge experiments using uninfected GL261 cells, we could show complete protection against the tumor, arguing for the induction of a T-cell-mediated, tumor-specific, long-term memory response. These findings indicate that the anticancer effect of PVs can be traced back not only for their direct oncolytic effect, but also to their ability to break tumor tolerance.     

Myo‐inositol trispyrophosphate‐mediated hypoxia reversion controls pancreatic cancer in rodents and enhances gemcitabine efficacy

Hypoxia and dysfunctional tumor vessels represent a prominent feature of pancreatic cancer, being, at least in part, responsible for chemotherapy resistance and immune suppression in these tumors. We tested whether the increase of oxygen delivery induced in vivo by myo‐inositol trispyrophosphate (ITPP) can reverse hypoxia, control tumor growth and improve chemotherapy response. Tumor size, metastatic development (microcomputed tomography scan follow‐up) and the survival of rats and nude or NOD.SCID mice, (bearing syngenic rat and MiaPaCa2‐ or patient‐derived pancreatic tumors), were determined on ITPP and/or gemcitabine treatment. Partial oxygen pressure, expression of angiogenic factors and tumor histology were evaluated. Infiltration and oxidative status of immune cells, as well as chemotherapy penetration in tumors, were determined by fluorescence‐activated cell sorting, fluorometry, nitric oxide release assays, Western blot and confocal microscopy. Weekly intravenous ITPP application resulted in the inhibition of metastasis development and restricted primary tumor growth, showing a superior effect on the rats' survival compared with gemcitabine. ITPP treatment restored tumor normoxia and caused a reduction in hypoxia inducible factor‐1α levels, with subsequent VEGF and Lox downregulation, resulting in improved vessel structure and decreased desmoplasia. The latter effects translated into elevated immune cells influx and improved susceptibility to gemcitabine treatment. Growth of human pancreatic tumor xenografts was strongly inhibited by administration of ITPP. ITPP exploits a two‐stage mechanism causing rapid, early and sustainable late stage normoxia. This is due to the angiogenic factor modulation and vascular normalization, leading to enhanced chemotherapy delivery and synergistic life prolongation, on combination with low doses of gemcitabine.     

Oncolytic Rat Parvovirus H-1PV, a Candidate for the Treatment of Human Lymphoma: In Vitro and In Vivo Studies

The incidence of lymphomas developing in both immunocompetent and immunosuppressed patients continues to steadily increase worldwide. Current chemotherapy and immunotherapy approaches have several limitations, such as severe side toxicity and selection of resistant cell variants. Autonomous parvoviruses (PVs), in particular the rat parvovirus H-1PV, have emerged as promising anticancer agents. Although it is apathogenic in humans, H-1PV has been shown to infect and suppress various rat and human tumors in animal models. In this study, we demonstrate the capacity of H-1PV for efficiently killing, through necrosis, cell cultures originating from Burkitt''s lymphoma (BL), while sparing normal B lymphocytes. The cytotoxic effect was generally accompanied by a productive H-1PV infection. Remarkably, parvovirus-based monotherapy efficiently suppressed established BL at an advanced stage in a severe combined immunodeficient (SCID) mouse model of the disease. The data show for the first time that an oncolytic parvovirus deserves further consideration as a potential tool for the treatment of some non-Hodgkin B-cell lymphomas, including those resistant to apoptosis induction by rituximab.     

Correlates of change in functional status of institutionalized geriatric schizophrenic patients: focus on medical comorbidity

OBJECTIVE: Impairment in basic self-care skills is common in patients with schizophrenia and is even more severe in elderly patients with a chronic course of institutional care. While cognitive impairment has proven to be a major predictor of overall functional deficit in schizophrenia, other potential factors, such as medical comorbidity, need to be considered. METHOD: Geriatric institutionalized schizophrenic patients (N=124) were assessed three times over 4 years to determine levels of positive and negative symptoms, impairment in activities of daily living, impairment in cognitive functioning, and medical problems. Path analysis was used to determine which variables best predicted changes in self-care functions. RESULTS: Functional status, negative symptoms, cognitive functions, and health status all significantly worsened during the follow-up. The path analyses showed that change in health status did not predict change in activities of daily living after the analysis accounted for negative symptoms and cognitive functions. DISCUSSION: The results highlight the relative importance of cognitive impairments in the functional impairments of older schizophrenic patients with increased medical burden.     

Behavior problems at ages 6 and 11 and high school academic achievement: Longitudinal latent variable modeling

Previous studies documented long-run effects of behavior problems at the start of school on academic achievement. However, these studies did not examine whether the observed effects of early behavior problems are explained by more proximate behavior problems, given the tendency of children's behavior problems to persist. Latent variable modeling was applied to estimate the effects of behavior problems at ages 6 and 11 on academic achievement at age 17, using data from a longitudinal study (n = 823). Behavior problems at ages 6 and 11, each stage independently of the other, predicted lower math and reading test scores at age 17, controlling for intelligence quotient (IQ), birth weight, maternal characteristics, family and community environment, and taking into account behavior problems at age 17. Behavior problems at the start of school, independent of later behavior problems, exert lingering effects on achievement by impeding the acquisition of cognitive skills that are the foundation for later academic progress.