Intra-host diversity of drug-resistant cytomegalovirus: A case report of cytomegalovirus infection after allogeneic hematopoietic cell transplantation.

Cytomegalovirus (CMV) is a major infectious agent causing severe complications in allogeneic hematopoietic cell transplantation (HCT) recipients, thereby warranting the need for aggressive preemptive or targeted antiviral therapy. However, prolonged or repeated use of antiviral agents, such as ganciclovir (GCV), foscarnet (FOS), and cidofovir (CDV), can result in drug-resistant CMV infection, posing challenges to successful outcomes. Here, we report a case of a patient with acute myeloid leukemia and drug-resistant CMV infection who presented with persistent CMV DNAemia, colitis, pneumonia, and encephalitis. An intra-host diversity of UL97 and UL54 mutations were detected through the genotypic resistance testing conducted on two blood samples (D+199 and D+224) and a cerebrospinal fluid (CSF) specimen (D+260) collected from the patient. UL97 L595W/L595F and L595W mutations were detected in the blood and CSF samples, respectively, that conferred GCV resistance. UL54 F412L mutation detected in all three samples conferred GCV/CDV resistance. However, the V787L mutation of UL54, conferring GCV/FOS resistance, was observed only in the D+224 blood sample. Despite combination therapy with FOS and high dose GCV and adjunctive therapy with leflunomide, the patient died from CMV infection and multiple organ failure on D+279. Further data on resistant mutations and intra-host diversity of CMV should be accumulated to elucidate the antiviral resistance and related outcomes.

Dioscin potentiates the antitumor effect of suicide gene therapy in melanoma by gap junction intercellular communication-mediated antigen cross-presentation.

Dioscin (Dio), steroid saponin, exists in several medicinal herbs with potent anticancer efficacy. This study aimed to explore the effect of Dio on the immune-related modulation and synergistic therapeutic effects of the herpes simplex virus thymidine kinase/ganciclovir (HSV-Tk/GCV) suicide gene therapy system in murine melanoma, thereby providing a research basis to improve the potential immunomodulatory mechanism underlying combination therapy. Using both in vitro and in vivo experiments, we confirmed the immunocidal effect of Dio-potentiated suicide gene therapy on melanoma. The results showed that Dio upregulated connexin 43 (Cx43) expression and improved gap junction intercellular communication (GJIC) in B16 cells while increasing the cross-presentation of antigens by dendritic cells (DCs), eventually promoting the activation and antitumor immune killing effects of CD8+ T lymphocytes. In contrast, inhibition or blockade of the GJIC function (overexpression of mutant Cx43 tumor cells/Gap26) partially reversed the potentiating effect. The significant synergistic effect of Dio on HSV-Tk/GCV suicide gene therapy was further investigated in a B16 xenograft mouse model. The increased number and activation ratio of CD8+ T lymphocytes and the levels of Gzms-B, IFN-γ, and TNF-α in mice reconfirmed the potential modulatory effects of Dio on the immune system. Taken together, Dio targets Cx43 to enhance GJIC function, improve the antigens cross-presentation of DCs, and activate the antitumor immune effect of CD8+ T lymphocytes, thereby providing insights into the potential immunomodulatory mechanism underlying combination therapy.

Therapeutic Effects of Mesenchymal Stem Cells Expressing Erythropoietin on Cancer-Related Anemia in Mice Model.

BACKGROUND: Cancer-related anemia (CRA) negatively influences cancer patients' survival, disease progression, treatment efficacy, and quality of life (QOL). Current treatments such as iron therapy, red cell transfusion, and erythropoietin-stimulating agents (ESAs) may cause severe adverse effects. Therefore, the development of long-lasting and curative therapies is urgently required. OBJECTIVE: In this study, a cell and gene therapy strategy was developed for in vivo delivery of EPO cDNA by way of genetic engineering of human Wharton's jelly mesenchymal stem cells (hWJMSCs) to produce and secrete human EPO protein for extended periods after transplantation into the mice model of CRA. METHODS: To evaluate CRA's treatment in cancer-free and cancerous conditions, first, a recombinant breast cancer cell line 4T1 which expressed herpes simplex virus type 1 thymidine kinase (HSV1-TK) by a lentiviral vector encoding HSV1-TK was developed and injected into mice. After three weeks, all mice developed metastatic breast cancer associated with acute anemia. Then, ganciclovir (GCV) was administered for ten days in half of the mice to clear cancer cells. Meanwhile, another lentiviral vector encoding EPO to transduce hWJMSCs was developed. Following implantation of rhWJMSCs-EPO in the second group of mice, peripheral blood samples were collected once a week for ten weeks from both groups. RESULTS: Analysis of peripheral blood samples showed that plasma EPO, hemoglobin (Hb), and hematocrit (Hct) concentrations significantly increased and remained at therapeutic for >10 weeks in both treatment groups. CONCLUSION: Data indicated that rhWJMSCs-EPO increased the circulating level of EPO, Hb, and Hct in both mouse subject groups and improved the anemia of cancer in both cancer-free and cancerous mice.

NUDT15 polymorphism influences the metabolism and therapeutic effects of acyclovir and ganciclovir.

Nucleobase and nucleoside analogs (NNA) are widely used as anti-viral and anti-cancer agents, and NNA phosphorylation is essential for the activity of this class of drugs. Recently, diphosphatase NUDT15 was linked to thiopurine metabolism with NUDT15 polymorphism associated with drug toxicity in patients. Profiling NNA drugs, we identify acyclovir (ACV) and ganciclovir (GCV) as two new NNAs metabolized by NUDT15. NUDT15 hydrolyzes ACV and GCV triphosphate metabolites, reducing their effects against cytomegalovirus (CMV) in vitro. Loss of NUDT15 potentiates cytotoxicity of ACV and GCV in host cells. In hematopoietic stem cell transplant patients, the risk of CMV viremia following ACV prophylaxis is associated with NUDT15 genotype (P = 0.015). Donor NUDT15 deficiency is linked to graft failure in patients receiving CMV-seropositive stem cells (P = 0.047). In conclusion, NUDT15 is an important metabolizing enzyme for ACV and GCV, and NUDT15 variation contributes to inter-patient variability in their therapeutic effects.

Inhibition of Cytomegalovirus Replication with Extended-Half-Life Synthetic Ozonides.

Artesunate (AS), a semisynthetic artemisinin approved for malaria therapy, inhibits human cytomegalovirus (HCMV) replication in vitro, but therapeutic success in humans has been variable. We hypothesized that the short in vivo half-life of AS may contribute to the different treatment outcomes. We tested novel synthetic ozonides with longer half-lives against HCMV in vitro and mouse cytomegalovirus (MCMV) in vivo Screening of the activities of four ozonides against a pp28-luciferase-expressing HCMV Towne recombinant identified OZ418 to have the best selectivity; its effective concentration inhibiting viral growth by 50% (EC50) was 9.8 ± 0.2 µM, and cytotoxicity in noninfected human fibroblasts (the concentration inhibiting cell growth by 50% [CC50]) was 128.1 ± 8.0 µM. In plaque reduction assays, OZ418 inhibited HCMV TB40 in a concentration-dependent manner as well as a ganciclovir (GCV)-resistant HCMV isolate. The combination of OZ418 and GCV was synergistic in HCMV inhibition in vitro Virus inhibition by OZ418 occurred at an early stage and was dependent on the cell density at the time of infection. OZ418 treatment reversed HCMV-mediated cell cycle progression and correlated with the reduction of HCMV-induced expression of pRb, E2F1, and cyclin-dependent kinases 1, 2, 4, and 6. In an MCMV model, once-daily oral administration of OZ418 had significantly improved efficacy against MCMV compared to that of twice-daily oral AS. A parallel pharmacokinetic study with a single oral dose of OZ418 or AS showed a prolonged plasma half-life and higher unbound concentrations of OZ418 than unbound concentrations of AS. In summary, ozonides are proposed to be potential therapeutics, alone or in combination with GCV, for HCMV infection in humans.

The Possible Mechanisms of HSV-TK/Hyperthermia Combined with 131I-antiAFPMcAb-GCV Nanospheres to Treat Hepatoma.

Our previous findings showed a good therapeutic effect of the combination of suicide gene HSV-TK, nuclide 131I, and magnetic fluid hyperthermia (MFH) on hepatoma by using magnetic nanoparticles as linkers, far better than any monotherapy involved, with no adverse effects. This combination therapy might be an eligible strategy to treat hepatic cancer. However, it is not clear how the combination regimen took the therapeutic effects. In the current study, to explore the possible mechanisms of radionuclide-gene therapy combined with MFH to treat hepatoma at tissue, cellular, and molecular levels and to provide theoretical and experimental data for its clinical application, we examined the apoptosis induction of the combination therapy and investigated the expression of the proteins related to apoptosis such as survivin, livin, bcl-2, p53, and nucleus protein Ki67 involved in cell proliferation, detected VEGF, and MVD involved in angiogenesis of tumor tissues and analyzed the pathologic changes after treatment. The results showed that the combination therapy significantly induced the hepatoma cell apoptosis. The expression of survivin, VEGF, bcl-2, p53, livin, Ki67, and VEGF proteins and microvascular density (MVD) were all decreased after treatment. The therapeutic mechanisms may be involved in the downregulation of Ki67 expression leading to tumor cell proliferation repression and inhibition of survivin, bcl-2, p53, and livin protein expression inducing tumor cell apoptosis, negatively regulating VEGF protein expression, and reducing vascular endothelial cells, which results in tumor angiogenesis inhibition and microvascular density decrease and tumor cell necrosis. These findings offer another basic data support and theoretical foundation for the clinical application of the combination therapy.

Hyperjaponol H, A New Bioactive Filicinic Acid-Based Meroterpenoid from Hypericum japonicum Thunb. ex Murray.

Hyperjaponol H (1), a new filicinic acid-based meroterpenoid, with a 6/6/10 ring system trans-fused by hetero-Diels-Alder cycloaddition between a germacrane sesquiterpenoid and a filicinic acid moiety, was isolated from aerial parts of Hypericum japonicum. The elucidation of its structure and absolute configuration were accomplished by the analyses of extensive spectroscopic data and the comparison of Cotton effects of electron circular dichroism (ECD) with previously reported ones. The bioactivity assay showed that hyperjaponol H exhibited a moderate inhibitory efficacy on lytic Epstein-Barr virus (EBV) DNA replication in B95-8 cells.

A combination hepatoma-targeted therapy based on nanotechnology: pHRE-Egr1-HSV-TK/(131)I-antiAFPMcAb-GCV/MFH.

Combination targeted therapy is a promising cancer therapeutic strategy. Here, using PEI-Mn0.5Zn0.5Fe2O4 nanoparticles (PEI-MZF-NPs) as magnetic media for MFH (magnetic fluid hyperthermia) and gene transfer vector for gene-therapy, a combined therapy, pHRE-Egr1-HSV-TK/(131)I-antiAFPMcAb-GCV/MFH, for hepatoma is developed. AntiAFPMcAb (Monoclonal antibody AFP) is exploited for targeting. The plasmids pHRE-Egr1-HSV-TK are achieved by incorporation of pEgr1-HSV-TK and pHRE-Egr1-EGFP. Restriction enzyme digestion and PCR confirm the recombinant plasmids pHRE-Egr1-HSV-TK are successfully constructed. After exposure to the magnetic field, PEI-MZF-NPs/pHRE-Egr1-EGFP fluid is warmed rapidly and then the temperature is maintained at 43 °C or so, which is quite appropriate for cancer treatment. The gene expression reaches the peak when treated with 200 µCi (131)I for 24 hours, indicating that the dose of 200 µCi might be the optimal dose for irradiation and 24 h irradiation later is the best time to initiate MFH. The in vitro and in vivo experiments demonstrate that pHRE-Egr1-HSV-TK/(131)I-antiAFPMcAb-GCV/MFH can greatly suppress hepatic tumor cell proliferation and induce cell apoptosis and necrosis and effectively inhibit the tumor growth, much better than any monotherapy does alone. Furthermore, the combination therapy has few or no adverse effects. It might be applicable as a strategy to treat hepatic cancer.

Icaritin induces lytic cytotoxicity in extranodal NK/T-cell lymphoma.

BACKGROUND: Extranodal NK/T-cell lymphoma (ENKL) is an aggressive hematological malignancy associated with Epstein-Barr virus (EBV) infection. It is often resistant to conventional chemotherapy and has a poor prognosis. Icaritin, a compound derived from Chinese herbal medicine, Herba Epimedii, has been reported to exert antitumor effects on a variety of cancer cell lines. In the present study, we investigated the cytotoxic effects of Icaritin on the two EBV-positive ENKL cell lines SNK-10 and SNT-8, along with the underlying molecular mechanisms. METHODS: ENKL cell lines SNK-10 and SNT-8 were exposed to different concentrations of Icaritin for the indicated time. Treated cells were analyzed for cell proliferation, cell cycle, and cell apoptosis. Phosphorylation of Stat3 and Akt proteins in signaling pathways and the EBV-encoded LMP1 proteins were measured by Western blot. Expression of EBV genes was assessed by Real-Time PCR. RESULTS: Our results showed that Icaritin dose-dependently inhibits ENKL cell proliferation and induces apoptosis and cell cycle arrest at G2/M phase. Additionally, Icaritin upregulates Bax, downregulates Bcl-2 and pBad, and activates caspase-3 and caspase-9. The anti-proliferative and pro-apoptotic effects of Icaritin are likely mediated by inhibition of Stat3 and Akt pathways through LMP1 downregulation. Importantly, Icaritin induces EBV lytic gene expression in ENKL cells, and the combination of Icaritin and the antiviral drug ganciclovir (GCV) is more effective in inducing ENKL cells apoptosis than Icaritin or GCV alone. CONCLUSIONS: These findings indicate that EBV-targeted approaches may have significant therapeutic potential for ENKL treatment.

Chimeric TK-NOG mice: a predictive model for cholestatic human liver toxicity.

Due to the substantial interspecies differences in drug metabolism and disposition, drug-induced liver injury (DILI) in humans is often not predicted by studies performed in animal species. For example, a drug (bosentan) used to treat pulmonary artery hypertension caused unexpected cholestatic liver toxicity in humans, which was not predicted by preclinical toxicology studies in multiple animal species. In this study, we demonstrate that NOG mice expressing a thymidine kinase transgene (TK-NOG) with humanized livers have a humanized profile of biliary excretion of a test (cefmetazole) drug, which was shown by an in situ perfusion study to result from interspecies differences in the rate of biliary transport and in liver retention of this drug. We also found that readily detectable cholestatic liver injury develops in TK-NOG mice with humanized livers after 1 week of treatment with bosentan (160, 32, or 6 mg/kg per day by mouth), whereas liver toxicity did not develop in control mice after 1 month of treatment. The laboratory and histologic features of bosentan-induced liver toxicity in humanized mice mirrored that of human subjects. Because DILI has become a significant public health problem, drug safety could be improved if preclinical toxicology studies were performed using humanized TK-NOG.

A continuous enzyme-coupled assay for triphosphohydrolase activity of HIV-1 restriction factor SAMHD1.

The development of deoxynucleoside triphosphate (dNTP)-based drugs requires a quantitative understanding of any inhibition, activation, or hydrolysis by off-target cellular enzymes. SAMHD1 is a regulatory dNTP-triphosphohydrolase that inhibits HIV-1 replication in human myeloid cells. We describe here an enzyme-coupled assay for quantifying the activation, inhibition, and hydrolysis of dNTPs, nucleotide analogues, and nucleotide analogue inhibitors by triphosphohydrolase enzymes. The assay facilitates mechanistic studies of triphosphohydrolase enzymes and the quantification of off-target effects of nucleotide-based antiviral and chemotherapeutic agents.

Assessment of drug candidates for broad-spectrum antiviral therapy targeting cellular pyrimidine biosynthesis.

Currently available antiviral drugs frequently induce side-effects or selection of drug-resistant viruses. We describe a novel antiviral principle based on targeting the cellular enzyme dihydroorotate dehydrogenase (DHODH). In silico drug design and biochemical evaluation identified Compound 1 (Cmp1) as a selective inhibitor of human DHODH in vitro (IC50 1.5±0.2nM). Crystallization data specified the mode of drug-target interaction. Importantly, Cmp1 displayed a very potent antiviral activity that could be reversed by co-application of uridine or other pyrimidine precursors, underlining the postulated DHODH-directed mode of activity. Human and animal cytomegaloviruses as well as adenoviruses showed strong sensitivity towards Cmp1 in cell culture-based infection systems with IC50 values in the low micromolar to nanomolar range. Particularly, broad inhibitory activity was demonstrated for various types of laboratory and clinically relevant adenoviruses. For replication of human cytomegalovirus in primary fibroblasts, antiviral mode of activity was attributed to the early stage of gene expression. A mouse in vivo model proved reduced replication of murine cytomegalovirus in various organs upon Cmp1 treatment. These findings suggested Cmp1 as drug candidate and validated DHODH as a promising cellular target for antiviral therapy.

Ganciclovir ophthalmic gel 0.15%: safety and efficacy of a new treatment for herpes simplex keratitis.

BACKGROUND: Until the availability of ganciclovir ophthalmic gel in 2009, the only option for treating herpes simplex (HSV) keratitis in the USA has been trifluridine (TFT), a compound with tolerability issues related to its nonselective inhibition of DNA replication in both normal cells and virus-infected cells. Ganciclovir has selective pharmacologic activity on viral thymidine kinase and a lower potential for toxicity to healthy human cells. Our objective was to evaluate safety and efficacy findings reported with the use of ganciclovir ophthalmic gel, both for HSV keratitis and other potential clinical indications. METHODS: Clinical and preclinical data with ganciclovir were identified through a comprehensive electronic search of PubMed and Medline, using the search terms ganciclovir, ganciclovir 0.15% ophthalmic gel, acyclovir, acyclovir ointment 3%, herpes simplex keratitis, treatment of herpes simplex keratitis, and adenoviral keratoconjunctivitis. The authors were also granted access to previously unpublished ganciclovir surveillance safety data from Bausch & Lomb, Inc. RESULTS: No clinical data comparing ganciclovir ophthalmic gel to 1% trifluorothymidine (TFT) for HSV keratitis could be identified. Four international, randomized, multicenter clinical trials have demonstrated that ganciclovir gel is at least as effective as acyclovir ointment for the treatment of HSV keratitis. Ganciclovir gel was better tolerated, with lower rates of blurred vision, eye irritation, and punctate keratitis. Recent data also indicate it may hold promise as a treatment for adenoviral keratoconjunctivitis. Worldwide safety surveillance data collected over the past 10-15 years in over 30 countries suggests an extremely low rate of spontaneously reported adverse events with ganciclovir ophthalmic gel. CONCLUSIONS: Current data suggest that ganciclovir ophthalmic gel has similar efficacy as acyclovir ointment for the treatment of HSV keratitis and is better tolerated. Clinical head-to-head studies comparing ganciclovir and TFT would be of great interest, especially for US physicians.

[Mechanism of DADS in the bystander effect of HSV-tk/GCV suicide gene therapy system in lens epithelial cells].

OBJECTIVE: To investigate the mechanism and effect of diallyl disulfide (DADS) on the bystander effect of herpes simplex virus kinase/ganciclovir (HSV-tk/GCV) suicide gene therapy system which was mediated by recombinant adeno-associated virus (rAAV) in lens epithelial cells. METHODS: Immunohistochemistry method was used to determine the distribution of connexin 43 (Cx43) protein in cultured rabbit lens epithelial cells and rabbit lens epithelial cells transfected by HSV-tk suicide gene. Cx43 protein was measured and analyzed in cultured rabbit lens epithelial cells and rabbit lens epithelial cells transfected by HSV-tk suicide gene that was induced by various DADS. Cell survival was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. RESULTS: DADS increased the Cx43 protein expression in cultured rabbit lens epithelial cells and rabbit lens epithelial cells transfected by HSV-tk suicide gene, and especially in 50 µmol/L DADS. After combining with DADS, the bystander effect was significantly improved (P<0.05). CONCLUSION: DADS can elevate the expression of Cx43 protein and enhance the bystander effect of HSV-tk/GCV suicide gene therapy system.

Oral maribavir for treatment of refractory or resistant cytomegalovirus infections in transplant recipients.

BACKGROUND: Despite advances in cytomegalovirus (CMV) prophylaxis and therapy, some transplant recipients still develop refractory CMV infections. Maribavir (MBV), an investigational benzimidazole antiviral agent, acts by a mechanism different from that of existing anti-CMV drugs. Previous Phase I and II studies have demonstrated a favorable safety profile for MBV, but its utility in treatment of complex CMV syndromes is unknown. METHODS: Between June and December 2008, MBV was released for use under individual emergency investigational new drug applications requested by treating physicians and approved by the US Food and Drug Administration and local institutional review boards. Six patients (5 solid organ transplant recipients and 1 hematopoietic stem cell transplant recipient) who had failed to respond to other therapies and/or had known ganciclovir-resistant CMV were treated with MBV at a starting oral dose of 400 mg twice daily. RESULTS: Patients were treated for a median of 207 days (range, 15-376). Four of 6 patients had no detectable CMV DNAemia within 6 weeks of starting MBV therapy. One patient, who had an initial viral load of 1.8 million copies/mL, developed MBV resistance mutations. One patient, who had low serum levels of MBV, had persistent CMV DNAemia and viruria without developing genotypic or phenotypic resistance to MBV. One patient cleared CMV DNAemia, but died of pneumonia and multiorgan failure. No significant adverse effects attributable to MBV were observed. CONCLUSIONS: MBV deserves further systematic evaluation as treatment for CMV infection that is resistant and/or refractory to standard therapies, but its optimal dose, duration of therapy, and use in combinations versus as a single agent have yet to be determined.

Human cytomegaloviruses expressing yellow fluorescent fusion proteins--characterization and use in antiviral screening.

Recombinant viruses labelled with fluorescent proteins are useful tools in molecular virology with multiple applications (e.g., studies on intracellular trafficking, protein localization, or gene activity). We generated by homologous recombination three recombinant cytomegaloviruses carrying the enhanced yellow fluorescent protein (EYFP) fused with the viral proteins IE-2, ppUL32 (pp150), and ppUL83 (pp65). In growth kinetics, the three viruses behaved all like wild type, even at low multiplicity of infection (MOI). The expression of all three fusion proteins was detected, and their respective localizations were the same as for the unmodified proteins in wild-type virus-infected cells. We established the in vivo measurement of fluorescence intensity and used the recombinant viruses to measure inhibition of viral replication by neutralizing antibodies or antiviral substances. The use of these viruses in a pilot screen based on fluorescence intensity and high-content analysis identified cellular kinase inhibitors that block viral replication. In summary, these viruses with individually EYFP-tagged proteins will be useful to study antiviral substances and the dynamics of viral infection in cell culture.

[Studies on evaluation of natural products for antiviral effects and their applications].

In the search for novel antiviral molecules from natural products, we have discovered various antiviral molecules with characteristic mechanisms of action. Scopadulciol (SDC), isolated from the tropical medicinal plant Scoparia dulcis L., showed stimulatory effects on the antiviral potency of acyclovir (ACV) or ganciclovir (GCV). This effect of SDC was exerted via the activation of viral thymidine kinase (HSV-1 TK) and, as a result, an increase in the cellular concentration of the active form of ACV/GCV, i.e., the triphosphate of ACV or GCV. On the basis of these experimental results, cancer gene therapy using the HSV-1 tk gene and ACV/GCV together with SDC was found to be effective in suppressing the growth of cancer cells in animals. Acidic polysaccharides such as calcium spirulan (Ca-SP) from Spirulina platensis, nostoflan from Nostoc flagelliforme, and a fucoidan from the sporophyll of Undaria pinnatifida (mekabu fucoidan) were also found to be potent inhibitors against several enveloped viruses. Their antiviral potency was dependent on molecular weight and content of the sulfate or carboxyl group as well as counterion species chelating with sulfate groups, indicating the importance of the three-dimensional structure of the molecules. In addition, unlike dextran sulfate, Ca-SP was shown to target not only viral absorption/penetration stages but also some replication stages of progeny viruses after penetration into cells. When mekabu fucoidan or nostoflan was administered with oseltamivir phosphate, their synergistic antiviral effects on influenza A virus were confirmed in vitro as well as in vivo.

Effectiveness of ganciclovir against human herpesvirus-6 excreted in saliva in stem cell transplant recipients.

The aim of this study was to evaluate the effect of ganciclovir on human herpesvirus-6 (HHV)-6. Forty allogeneic stem cell transplant recipients were prospectively studied by repeated sampling of the saliva. The saliva samples were assayed for HHV-6 by quantitative polymerase chain reaction. HHV-6 was detected in 33 patients. Ganciclovir was given as preemptive therapy for cytomegalovirus infection during 15 episodes that were compared to 18 episodes without any concomitant antiviral therapy. The mean HHV-6 load decreased 0.49 (s.e. 0.31) log(10)/week in patients receiving ganciclovir whereas it increased 0.15 (s.e. 0.17) log(10)/week in episodes without antiviral therapy (P=0.04). We conclude that ganciclovir can decrease the HHV-6 viral load in saliva.

Inhibition of ganciclovir-resistant human cytomegalovirus replication by Kampo (Japanese herbal medicine).

We examined the effect of Kampo on the replication of ganciclovir (GCV)-resistant human cytomegalovirus (HCMV) in the human embryonic fibroblast cell line MRC-5. Treatment of HCMV-infected cells with Sho-seiryu-to (SST; Xiao-Qing-Long-Tang in Chinese) resulted in the inhibition of viral replication without affecting the cell growth. SST treatment decreased the synthesis of viral DNA, but had no virucidal effect on cell-free HCMV. However, the inhibitory effect of SST on HCMV replication was ablated by anti-interferon-beta (IFN-beta) antibody suggesting that SST inhibits the replication of GCV-resistant HCMV through the induction of IFN-beta. These results suggest that SST is a novel compund with potential as an anti-HCMV.

Heat-directed suicide gene therapy mediated by heat shock protein promoter for gastric cancer.

The prognosis of patients with metastatic gastric cancer, particularly peritoneal carcinomatosis, remains poor despite intensive interventions. Gene therapy and hyperthermia can be promising strategies for such advanced disease. The study was conducted to explore the possible effective therapeutic approach of suicide gene therapy with herpes simplex virus thymidine kinase (HSV-tk) in combination with hyperthermia for advanced gastric cancer. The heat shock protein (hsp) 70B gene promoter-oriented HSV-tk (HSP-tk)/ganciclovir (GCV) system directed by heat shock was developed. Hsp promoter activity under the control of heating was assessed by dual luciferase assay in gastric cancer cell lines and implanted tumors of nude mice. In vitro cytotoxic assay was performed using the HSP-tk/GCV delivered by the hemagglutinating virus of Japan (HVJ) liposome, with or without heating. Mice with subcutaneously xenografted tumors and peritoneal carcinomatosis were treated with hyperthermia and gene therapy using the HVJ-liposome-carrying HSP-tk. Assessment by luciferase assay demonstrated highly inducible and tumor-specific promoter activity in vitro and in vivo. Cytotoxic assays showed that cells transfected with HSP-tk became more sensitive to GCV with heating. A synergistic effect was also observed when treated with a non-heat-inducible cytomegalovirus (CMV) promoter-mediated HSV-tk/GCV and heating, indicating bystander killing. The HVJ-liposome-carrying HSP-tk/GCV combined with hyperthermia significantly inhibited the growth of subcutaneous tumors and prolonged survival of mice with peritoneal carcinomatosis. We conclude that the combination of suicide gene therapy with hyperthermia can provide a promising treatment modality for advanced gastric cancer.