Showing papers by "Robert L. Martuza published in 2013"

Multifaceted oncolytic virus therapy for glioblastoma in an immunocompetent cancer stem cell model.

Abstract: Glioblastoma (World Health Organization grade IV) is an aggressive adult brain tumor that is inevitably fatal despite surgery, radiation, and chemotherapy. Treatment failures are attributed to combinations of cellular heterogeneity, including a subpopulation of often-resistant cancer stem cells, aberrant vasculature, and noteworthy immune suppression. Current preclinical models and treatment strategies do not incorporate or address all these features satisfactorily. Herein, we describe a murine glioblastoma stem cell (GSC) model that recapitulates tumor heterogeneity, invasiveness, vascularity, and immunosuppressive microenvironment in syngeneic immunocompetent mice and should prove useful for a range of therapeutic studies. Using this model, we tested a genetically engineered oncolytic herpes simplex virus that is armed with an immunomodulatory cytokine, interleukin 12 (G47-mIL12). G47Δ-mIL12 infects and replicates similarly to its unarmed oncolytic herpes simplex virus counterpart in mouse 005 GSCs in vitro, whereas in vivo, it significantly enhances survival in syngeneic mice bearing intracerebral 005 tumors. Mechanistically, G47-mIL12 targets not only GSCs but also increases IFN-γ release, inhibits angiogenesis, and reduces the number of regulatory T cells in the tumor. The increased efficacy is dependent upon T cells, but not natural killer cells. Taken together, our findings demonstrate that G47Δ-mIL12 provides a multifaceted approach to targeting GSCs, tumor microenvironment, and the immune system, with resultant therapeutic benefit in a stringent glioblastoma model.

Combination of vinblastine and oncolytic herpes simplex virus vector expressing IL-12 therapy increases antitumor and antiangiogenic effects in prostate cancer models.

Abstract: Oncolytic herpes simplex virus-1 (oHSV)–based vectors selectively replicate in tumor cells causing direct killing, ie., oncolysis, while sparing normal cells. oHSV’sare promising anticancer agents, but their efficacy, when used as single agents, leaves room for improvement. We hypothesized that combining the direct oncolytic and antiangiogenic activities of the IL-12 secreting NV1042 oHSV with microtubule disrupting agents (MDA’s) would be an effective means to enhance antitumor efficacy. Vinblastine (VB) was identified among several MDA’s screened that displayed consistent and potent cytotoxic killing of both prostate cancer and endothelial cell lines. In matrigel tube forming assays, VB was found to be highly effective at inhibiting tube formation of HUVEC cells. The combination of VB with NV1023 (the parental virus lacking IL-12) or NV1042 showed additive or synergistic activity against prostate cancer cell lines and was not due to increased oHSV replication by VB. In athymic mice bearing CWR22 prostate tumors, VB in combination with NV1042 was superior to the combination of VB plus NV1023 in reducing tumor burden, appeared to be nontoxic and resulted in a statistically significant diminution in the number of CD31 + cells as compared to other treatment groups. In human organotypic cultures using surgical samples from radical prostatectomies, both NV1023 and NV1042 were localized specifically to the epithelial cells of prostatic glands but not to the surrounding stroma. These data highlight the therapeutic advantage of combining the dual-acting anti-tumor and anti-angiogenic activities of oHSV’s and MDA’s.

24-Year-Old Woman with An Internal Auditory Canal Mass

Abstract: Benign peripheral nerve sheath tumors are divided into schwannomas, neurofibromas and perineuriomas. In recent years, tumors with hybrid features, composed of multiple, discrete areas of different histological types, were described. These tumors may represent a diagnostic challenge. A 24-year-old woman with multiple sclerosis was found to have a 1.3 cm TV × 0.7 cm AP T2 intermediate lesion within the left internal auditory canal. Gross examination revealed a tan-white, well circumscribed mass. Histologic examination demonstrated a well demarcated, cellular, solid neoplasm with a biphasic pattern. Most of the tumor was composed of spindle cells arranged in fascicles with focal Verocay body formation and diffuse S100 positivity. A second, minor area showed concentric proliferation of neoplastic spindle cells around one or more axons. Tumor cells in this area were positive for perineurial markers, claudin-1 and Glut-1, and focally immunopositive for CD34.We present here a case of a benign peripheral nerve sheath tumor with histological and immunohistochemical features consistent with a dual pattern of differentiation of schwannoma and perineurioma, in the VIIIth cranial nerve. This is, to our knowledge, the first case of a hybrid perineurioma/schwannoma reported in a cranial nerve.