acyclovir and Glioblastoma

Herpes simplex virus encephalitis (HSE) is the most common cause of letal encephalitis and its prevalence appears higher among oncologic patients who undergo brain radiotherapy (RT). We describe a case of 76-year-old woman with glioblastoma multiforme (GBM) who developed HSE shortly after brain RT. Cerebrospinal fluid analysis (CSF) was normal and the diagnosis was driven by brain MRI and EEG. Prompt introduction of antiviral therapy improved the clinical picture. We highlight the importance of EEG and brain MRI for the diagnosis and suggest the possibility of antiviral profilaxys in oncologic patients who undergo brain RT.

Topics: Acyclovir; Aged; Brain Neoplasms; Cranial Irradiation; Electroencephalography; Encephalitis, Herpes Simplex; Female; Glioblastoma; Herpesvirus 1, Human; Humans; Magnetic Resonance Imaging; Prognosis; Risk Assessment; Treatment Outcome

Glioblastoma multiforme (GBM) is the most common primary malignant tumor of the central nervous system (CNS) and one of the most lethal cancers in adults and children. Despite aggressive treatment with surgery, radiation, and chemotherapy, median survival is less than 15 months and overall survival is less than 10 % at 5 years. Development of therapeutics for malignant gliomas has been hampered by their natural complexity as well as protective mechanisms unique to the CNS. Better understanding of the pathogenesis of GBM is opening the path to novel, specific-targeted therapies. Recently, multiple immunotherapy approaches have been acquiring substantial indication of therapeutic efficacy with a very safe profile. Examples of the leading clinical approaches for GBM will be discussed in detail in this review.

Topics: Acyclovir; Autoantigens; Central Nervous System Neoplasms; Combined Modality Therapy; Dacarbazine; Dendritic Cells; Glioblastoma; Humans; Immunotherapy; Immunotherapy, Active; Signal Transduction; Temozolomide; Valacyclovir; Valine

We have previously demonstrated safety of G207, a doubly mutated (deletion of both gamma(1)34.5 loci, insertional inactivation of U(L)39) herpes simplex virus (HSV) for patients stereotactically inoculated in enhancing portions of recurrent malignant gliomas. We have now determined safety of two inoculations of G207, before and after tumor resection. Inclusion criteria were histologically proven recurrent malignant glioma, Karnofsky score >or=70, and ability to resect the tumor without ventricular system breach. Patients received two doses of G207 totaling 1.15 x 10(9) plaque-forming units with 13% of this total injected via a catheter placed stereotactically in the tumor. Two or five days later, tumor was resected en bloc with catheter in place. The balance of G207 dose was injected into brain surrounding the resection cavity. Six patients with recurrent glioblastoma multiforme were enrolled. Two days after the second G207 inoculation, one patient experienced transient fever, delirium, and hemiparesis, which entirely resolved on high-dose dexamethasone. No patient developed HSV encephalitis or required treatment with acyclovir. Radiographic and neuropathologic evidence suggestive of antitumor activity is reported. Evidence of viral replication was demonstrated. G207 appears safe for multiple dose delivery, including direct inoculation into the brain surrounding tumor resection cavity.

Topics: Acyclovir; Adult; Aged; Antibodies, Viral; Brain Neoplasms; Female; Glioblastoma; Humans; Male; Middle Aged; Neoplasm Recurrence, Local; Simplexvirus; Treatment Outcome; Virus Replication

Human cytomegalovirus (HCMV) is a beta herpesvirus which large amount of people in world has interacted with. Recent studies indicated that CMV DNA is associated with several cancer types including "Glioblastoma (GBM)" which is the most common and aggressive type of primary brain cancer. In clinical studies it was shown that several antiviral medicines prolonged life span of glioblastoma patients. One of them is Acyclovir (ACV) which is a type of nucleoside analog, used to cure viral infections and might be a potential treatment supplement for Glioblastoma. In this study we aimed to investigate if ACV had cytotoxic effect on glioblastoma cell line U87 MG and also the effect of ACV on healthy cells. Furthermore it was aimed to search the effect of Rosmarinus Officinalis also known as rosemary which is an aromatic, perennial plant concurrent with ACV on glioblastoma and healthy cells.

Topics: Acyclovir; Animals; Cell Survival; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Mice; Plant Extracts; Rosmarinus; Survivin; Tumor Cells, Cultured

Regulatory T cells, Tregs, are a subset of lymphocytes that have immunosuppressive attributes. They are elevated in blood of glioblastoma patients and within this tumor's tissue itself. Indoleamine 2,3-dioxygenase, IDO, converts tryptophan to kynurenine. IDO activity enhances Treg formation by pathways that are unknown. Experimentally, inhibition of IDO decreases Treg function and number in rodents. The common anti-viral agent acyclovir inhibits IDO. Acyclovir may thereby decrease Treg function in glioblastoma. If it can be confirmed that Treg counts are elevated in glioblastoma patients' tumor tissue, and if we can document acyclovir's lowering of tissue Treg counts by a small trial of acyclovir in pre-operative glioblastoma patients, a trial of acyclovir effect on survival should be done given the current poor prognosis of glioblastoma and the well-established safety and low side effect burden of acyclovir.

Topics: Acyclovir; Glioblastoma; Humans; Indoleamine-Pyrrole 2,3,-Dioxygenase; T-Lymphocytes, Regulatory

Topics: Acyclovir; Antibodies, Viral; Brain Neoplasms; Clinical Trials as Topic; Glioblastoma; Humans; Neoplasm Recurrence, Local; Simplexvirus; Treatment Outcome; Virus Replication

The most extensively investigated strategy of suicide gene therapy for treatment of cancer is the transfer of the herpes simplex virus thymidine kinase (HSV-TK) gene followed by administration of antiviral prodrugs such as acyclovir (ACV) and ganciclovir (GCV). The choice of the agent that can stimulate HSV-TK enzymatic activity is one of the determinants of the usefulness of this strategy. Previously, we found that a diterpenoid, scopadulciol (SDC), produced a significant increase in the active metabolite of ACV. This suggests that SDC may play a role in the HSV-TK/prodrug administration system.. The anticancer effect of SDC was evaluated in HSV-TK-expressing (TK+) cancer cells and nude mice bearing TK+ tumors. In vitro and in vivo enzyme assays were performed using TK+ cells and tumors. The phosphorylation of ACV monophosphate (ACV-MP) was measured in TK- cell lysates. The pharmacokinetics of prodrugs was evaluated by calculating area-under-the-concentration-time-curve values.. SDC stimulated HSV-TK activity in TK+ cells and tumors, and increased GCV-TP levels, while no effect of SDC was observed on the phosphorylation of ACV-MP to ACV-TP by cellular kinases. The SDC/prodrug combination altered the pharmacokinetics of the prodrugs. In accord with these findings, SDC enhanced significantly the cell-killing activity of prodrugs. The bystander effect was also significantly augmented by the combined treatment of ACV/GCV and SDC.. SDC was shown to be effective in the HSV-TK/prodrug administration system and improved the efficiency of the bystander effect of ACV and GCV. The findings will be considerably valuable with respect to the use of GCV in lower doses and less toxic ACV. This novel strategy of drug combination could provide benefit to HSV-TK/prodrug gene therapy.

Topics: Abietanes; Acyclovir; Animals; Antiviral Agents; Biological Availability; Carcinoma; Cell Line, Tumor; Female; Ganciclovir; Genes, Neoplasm; Genetic Therapy; Glioblastoma; HeLa Cells; Herpes Simplex; Herpesvirus 1, Human; Humans; Laryngeal Neoplasms; Mice; Mice, Nude; Molecular Structure; Plasmids; Prodrugs; Thymidine Kinase; Transfection; Urinary Bladder Neoplasms; Xenograft Model Antitumor Assays

Glioblastoma multiforme is one of the most aggressive and frequently occurring forms of brain cancer. It originates from astrocytes and is characterized by a loss of cell cycle control frequently involving mutations in tumor suppressor genes, such as p53 and p16. Nucleoside analogs, such as acyclovir (ACV), are currently being used in the treatment of viral diseases, such as those caused by members of the herpes family. Further, ACV in combination with type I interferons (IFN) has been shown to be more effective at lower doses in treatment of viral diseases. We show here that ACV at high concentrations (up to 500 microg/ml) inhibited growth in tissue culture of the human glioblastoma cell lines T98G, SNB-19, and U-373 by as much as 68.3% while inhibiting normal human astrocytes by only 38.3%. Related to this, the tumor cells were more than sevenfold more efficient in phosphorylation of ACV to the active phosphate form than normal human astrocytes. Analogous to treatment of virus-infected cells, suboptimal concentrations of ACV were as effective as high concentrations when used in conjunction with low concentrations of IFN-gamma in inhibition of tumor cell growth. At the cellular level, ACV and IFN-gamma inhibited the cell cycle in both the G1 and S phases. The cooperative effect of ACV and IFN-gamma against the glioblastomas appears to be due to direct inhibition of DNA synthesis by ACV in the S phase of the cell cycle and induction by IFN-gamma of the tumor suppressor gene p21wAF1/CIP1, which in turn acts at the level of proliferating cell nuclear antigen (PCNA) and cyclin E/cyclin-dependent kinase 2 (Cdk2) binding and inhibition of function. These studies show that the combination of IFN-gamma and ACV at suboptimal concentrations elicits significant antiproliferative effects on the glioblastoma cell lines T98G, SNB-19, and U-373 while having very little effect on normal human astrocyte cell proliferation.

Topics: Acyclovir; Antiviral Agents; Astrocytes; Brain Neoplasms; CDC2-CDC28 Kinases; Cell Cycle; Cell Division; Cell Line; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinases; Cyclins; Drug Synergism; Glioblastoma; Humans; Interferon-gamma; Proliferating Cell Nuclear Antigen; Protein Serine-Threonine Kinases; Recombinant Proteins; Tumor Cells, Cultured