Combination Of Ganciclovir Research Articles

Can Ganciclovir and Quercetin-P188 Ameliorate Cytomegalovirus Induced Hearing Loss?

Determine whether combination therapy with ganciclovir (GCV) and a Quercetin-P188 solution improves hearing outcomes in a murine cytomegalovirus (CMV) model. BALB/c mice were infected with murine CMV on postnatal day 3 (p3). Quercetin was solubilized in saline using P188 (QP188). Treatment groups received either GCV, QP188, GCV and QP188, or P188 delivery vehicle BID at 12-hour intervals via intraperitoneal injection. All treatment groups were treated for 14 days starting at p3. Uninfected controls were treated with the combined regimen, saline or P188 delivery vehicle. Auditory thresholds were assessed using distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) testing at 4, 6, and 8 weeks of age. Temporal bones from separate CMV-infected groups were harvested at p10, and viral load was determined by quantitative polymerase chain reaction. CMV-infected mice receiving combination therapy GCV+QP188 demonstrated statistically significant lower ABR (p < 0.001) and DPOAE thresholds (p < 0.001) compared with mice treated with GCV monotherapy, QP188 monotherapy, and P188 delivery vehicle at 4, 6, and 8 weeks of age. GCV+QP188 combination therapy, GCV monotherapy, and QP188 monotherapy resulted in a nonsignificant reduction in mean viral titers compared to P188 monotherapy (p = 0.08). Combining GCV with the excipients quercetin and P188 effectively ameliorated CMV-induced sensorineural hearing loss in a murine model. This result may be partially explained by a reduction in viral titers in mouse temporal bones that correlate with in vitro studies demonstrating additive antiviral effect in cell culture. NA Laryngoscope, 134:1457-1463, 2024.

Heterogeneity and viral replication fitness of HSV-1 clinical isolates with mutations in the thymidine kinase and DNA polymerase.

Prolonged antiviral therapy in immunocompromised individuals can result in the emergence of (multi)drug-resistant herpes simplex virus 1 (HSV-1) infections, forming a therapeutic challenge. To evaluate spatial and temporal differences in drug resistance of HSV-1 samples from a HSCT recipient and to determine the effect of resistance mutations on viral replication fitness. Five HSV-1 isolates were recovered from a HSCT recipient who suffered from persistent HSV-1 lesions, consecutively treated with aciclovir, foscarnet, cidofovir and a combination of ganciclovir and cidofovir. Spatial and temporal differences in HSV-1 drug resistance were evaluated genotypically [Sanger sequencing and next-generation sequencing (NGS) of the viral thymidine kinase (TK) and DNA polymerase (DP)] and phenotypically (plaque reduction assay). Viral replication fitness was determined by dual infection competition assays. Rapid evolution to aciclovir and foscarnet resistance was observed due to acquisition of TK (A189V and R222H) and DP (L778M and L802F) mutations. Virus isolates showed heterogeneous populations, spatial virus compartmentalization and minor viral variants in three out of five isolates (detectable by NGS but not by Sanger sequencing). Mutations in the TK and DP genes did not alter replication fitness without drug pressure. TK and/or DP mutants influenced replication fitness under antiviral pressure and showed increased fitness under pressure of the drug they showed resistance to. The use of NGS and dual infection competition assays revealed rapid evolution of HSV-1 drug resistance in a HSCT recipient with spatial and temporal compartmentalization of viral variants that had altered replication fitness under antiviral pressure.

Clinical Study of Modified Sub-Hibernation Therapy Combined with Ganciclovir on Patients with Viral Encephalitis

Viral encephalitis is an infectious disease of the nervous system caused by multiple viruses entering the brain. This disease is extremely harmful to the human body and has a high mortality rate. Modified sub-hibernation therapy and ganciclovir are the most commonly used treatments for viral encephalitis. The purpose of this article is to further explore the clinical effect of modified sub-hibernation therapy combined with ganciclovir on patients with viral encephalitis. Thirty viral encephalitis patients with severe illness and long-term illness were taken as the research object, and the patients were divided into three groups according to the condition and their own conditions, a control group, a ganciclovir treatment group and a modified sub-hibernation therapy combined ganciclovir observation group. The control group did not receive any treatment, the treatment group was treated with ganciclovir alone, and the observation group was treated with modified sub-hibernation therapy combined with ganciclovir. The diagnosis and prognosis of all patients were analyzed and studied. The results of the study showed that the treatment effective rate of the ganciclovir treatment group was 85.7%, and three patients relapsed after discharge from the hospital. The recurrence rate was 30%. The total effective rate of the modified sub-hibernation therapy combined with the ganciclovir observation group was 95.3%, only one person relapsed after discharge, the recurrence rate was 10%. It can be seen that the treatment of viral encephalitis with modified sub-hibernation therapy combined with ganciclovir has a very good therapeutic effect and the disease recurrence rate is low. It is the first choice for the treatment of viral encephalitis.

Ganciclovir and Its Hemocompatible More Lipophilic Derivative Can Enhance the Apoptotic Effects of Methotrexate by Inhibiting Breast Cancer Resistance Protein (BCRP)

Efflux transporters, namely ATP-binding cassette (ABC), are one of the primary reasons for cancer chemoresistance and the clinical failure of chemotherapy. Ganciclovir (GCV) is an antiviral agent used in herpes simplex virus thymidine kinase (HSV-TK) gene therapy. In this therapy, HSV-TK gene is delivered together with GCV into cancer cells to activate the phosphorylation process of GCV to active GCV-triphosphate, a DNA polymerase inhibitor. However, GCV interacts with efflux transporters that are responsible for the resistance of HSV-TK/GCV therapy. In the present study, it was explored whether GCV and its more lipophilic derivative (1) could inhibit effluxing of another chemotherapeutic, methotrexate (MTX), out of the human breast cancer cells. Firstly, it was found that the combination of GCV and MTX was more hemocompatible than the corresponding combination with compound 1. Secondly, both GCV and compound 1 enhanced the cellular accumulation of MTX in MCF-7 cells, the MTX exposure being 13–21 times greater compared to the MTX uptake alone. Subsequently, this also reduced the number of viable cells (41–56%) and increased the number of late apoptotic cells (46–55%). Moreover, both GCV and compound 1 were found to interact with breast cancer resistant protein (BCRP) more effectively than multidrug-resistant proteins (MRPs) in these cells. Since the expression of BCRP was higher in MCF-7 cells than in MDA-MB-231 cells, and the cellular uptake of GCV and compound 1 was smaller but increased in the presence of BCRP-selective inhibitor (Fumitremorgin C) in MCF-7 cells, we concluded that the improved apoptotic effects of higher MTX exposure were raised mainly from the inhibition of BCRP-mediated efflux of MTX. However, the effects of GCV and its derivatives on MTX metabolism and the quantitative expression of MTX metabolizing enzymes in various cancer cells need to be studied more thoroughly in the future.

THE METHOD OF TREATMENT OF GENERALIZED CYTOMEGALOVIRUS INFECTION IN INFANTS

Purpose of the study. Evaluation of the effectiveness of treatment of generalized cytomegalovirus infection (CMVI) in infants with a combination of ganciclovir and VIFERON®. Materials and methods. 52 children of the first months of life were treated with generalized CMV. Patients are divided into 3 groups: the first included 25 children who received ganciclovir for 14—21 days, then — IFN-α-2b in combination with antioxidants vitamins E and C (VIFERON®); The second group consisted of 17 patients receiving only ganciclovir; in the third group included 10 children who had only symptomatic treatment of CMVI: hepatoprotectors, broad-spectrum antibiotics (ceftriaxone, ampicillins) at age dosages. Therapy was carried out under the control of viral load in the blood serum on the 14th and 21st day from the start of treatment. Patients of the 1st group with a decrease in the clinical manifestations of CMV and a decrease in the viral load to 104—103 copies/ml on the 14—21 day were prescribed rectal suppositories of IFN-α-2b (VIFERON®) 150 000 IU according to the original scheme. Results. In the 1st group, all children during 3—6 months had an elimination of the virus from the blood and liquor. Relapse of CMV was not observed. Children of the second group had a decrease in the viral load was observed, but the elimination of the virus from the blood, the cerebrospinal fluid did not occur. Patients of the 3rd group had the viral load remained at the same level, it increased by 102 copies/ml at one patient. The conclusion. Using of combined antiviral therapy with ganciclovir and IFN-α-2b in combination with antioxidants vitamins E and C (VIFERON®) promotes elimination of the virus from blood and liquor, transferring and keeping it in an inactive state, which prevents the development of complications. The proposed method for treatment of CMV can be successfully used in inpatient and outpatient settings.

Arsenic trioxide inhibits EBV reactivation and promotes cell death in EBV-positive lymphoma cells

BackgroundEpstein-Barr Virus (EBV) is associated with hematopoietic malignancies, such as Burkitt’s lymphoma, post-transplantation lymphoproliferative disorder, and diffuse large B-cell lymphoma. The current approach for EBV-associated lymphoma involves chemotherapy to eradicate cancer cells, however, normal cells may be injured and organ dysfunction may occur with currently employed regimens. This research is focused on employing arsenic trioxide (ATO) as EBV-specific cancer therapy takes advantage of the fact the EBV resides within the malignant cells.Methods and resultsOur research reveals that low ATO inhibits EBV gene expression and genome replication. EBV spontaneous reactivation starts as early as 6 h after re-suspending EBV-positive Mutu cells in RPMI media in the absence of ATO, however this does not occur in Mutu cells cultured with ATO. ATO’s inhibition of EBV spontaneous reactivation is dose dependent. The expression of the EBV immediate early gene Zta and early gene BMRF1 is blocked with low concentrations of ATO (0.5 nM – 2 nM) in EBV latency type I cells and EBV-infected PBMC cells. The combination of ATO and ganciclovir further diminishes EBV gene expression. ATO-mediated reduction of EBV gene expression can be rescued by co-treatment with the proteasome inhibitor MG132, indicating that ATO promotes ubiquitin conjugation and proteasomal degradation of EBV genes. Co-immunoprecipitation assays with antibodies against Zta pulls down more ubiquitin in ATO treated cell lysates. Furthermore, MG132 reverses the inhibitory effect of ATO on anti-IgM-, PMA- and TGF-β-mediated EBV reactivation. Thus, mechanistically ATO’s inhibition of EBV gene expression occurs via the ubiquitin pathway. Moreover, ATO treatment results in increased cell death in EBV-positive cells compared to EBV-negative cells, as demonstrated by both MTT and trypan blue assays. ATO-induced cell death in EBV-positive cells is dose dependent. ATO and ganciclovir in combination further enhances cell death specifically in EBV-positive cells.ConclusionATO-mediated inhibition of EBV lytic gene expression results in cell death selectively in EBV-positive lymphocytes, suggesting that ATO may potentially serve as a drug to treat EBV-related lymphomas in the clinical setting.

Ganciclovir and Foscarnet Therapy of Cytomegalovirus-Associated Meningoencephalitis in a Hemodialysis Patient With Liver Transplantation: Case Report

Cytomegalovirus (CMV) infection in patients with liver transplantation (LT) remains a highly prevalent complication with a significant increase in morbidity and mortality. However, CMV-associated meningoencephalitis is rarely diagnosed, and treatment is very difficult. The aim of the present report is to review the experience of successful treatment with combined ganciclovir and foscarnet of CMV-associated meningoencephalitis refractory to ganciclovir alone in a hemodialysis (HD) patient after LT. A 54-year-old woman with end-stage renal disease on HD developed a seizure with loss of consciousness. She had received a liver transplant 4 months before. Blood CMV polymerase chain reaction was positive, and cerebrospinal fluid (CSF) analysis was compatible with viral meningitis. Brain magnetic resonance imaging (MRI) showed extensive dural thickening with enhancement and a round ring-like enhancement in the left centrum semiovale. She was diagnosed with CMV-associated meningoencephalitis. At that time, ganciclovir was started intravenously. After that, there were no improvements in mental state, CSF analysis, or brain MRI. Intravenous foscarnet at reduced dose was added to ganciclovir therapy. With combined ganciclovir and foscarnet, there was a slight improvement in her mental state and brain MRI.

Synergistic effects by combination of ganciclovir and tricin on human cytomegalovirus replication in vitro

It has been demonstrated as the first report that combination treatment with ganciclovir (GCV) and tricin (4′,5,7-trihydroxy-3′,5′ -dimethoxyflavone), a derivative of Sasa albo-marginata, after human cytomegalovirus (HCMV) infection has synergistic effects on both infectious virus production and HCMV DNA synthesis in the human embryonic fibroblast cell line MRC-5. In this paper, we examined the anti-HCMV effects of GCV plus various concentrations of tricin, and tricin plus various concentrations of GCV in MRC-5 cells. We found that expression of the HCMV UL54 gene was significantly inhibited by combination of GCV with tricin when compared with GCV mono-treatment. These results suggest that tricin is a novel compound for combination therapy with GCV against HCMV replication. In addition, reduced-dose combination therapy may provide a direction for treatment in patients with HCMV infection while reducing drug toxicity.

In Vitro Combination of Anti-Cytomegalovirus Compounds Acting through Different Targets: Role of the Slope Parameter and Insights into Mechanisms of Action

Conventional therapy for human cytomegalovirus (CMV) relies on inhibition of the viral DNA polymerase. Ganciclovir (GCV) is the first-line therapy, but when GCV-resistant strains emerge, alternative therapies are extremely limited and are associated with significant toxicities. Combination of anti-CMV agents that act on different targets or stages of virus replication has not been well studied, mostly because of the limited number of anti-CMV agents. We report our investigation of combinations of agents that inhibit CMV by targeting the viral DNA polymerase, cellular kinases, or other cell/virus mechanisms yet to be discovered. The selected compounds differed by the slopes of their dose-response curve: compounds with a slope of 1 (GCV) representing one target or noncooperativity and compounds with high slopes indicating positive cooperativity. Analysis of anti-CMV drug combinations using the Bliss model (which accounts for the slope parameter) distinguished between combinations with synergistic, antagonistic, and additive activities. The combination of GCV and foscarnet was slightly synergistic; strong synergism was found when GCV was used with artemisinin-derived monomers or dimers or the MEK inhibitor U0126. The combination of GCV and cardiac glycosides (digoxin, digitoxin, and ouabain) was additive. The monomeric artemisinin artesunate was synergistic when combined with U0126 or the multikinase inhibitor sunitinib. However, the combination of artemisinin-derived dimers (molecular weights, 606 and 838) and U0126 or sunitinib was antagonistic. These results demonstrate that members of a specific drug class show similar patterns of combination with GCV and that the slope parameter plays an important role in the evaluation of drug combinations. Lastly, antagonism between different classes of CMV inhibitors may assist in target identification and improve the understanding of CMV inhibition by novel compounds.

Combined RNA interference of adenine nucleotide translocase-2 and ganciclovir therapy in hepatocellular carcinoma

The purpose of this study was to investigate the anticancer effects of combined RNA interference (RNAi) of the adenine nucleotide translocase-2 (ANT2) gene and ganciclovir (GCV) therapy for treatment of hepatocellular carcinoma cells (Huh 7) in an animal model. The Huh 7/NTG stable cell line was established by transfection of a vector with the human sodium iodide symporter (hNIS), HSV1-sr39 thymidine kinase (tk), and enhanced green florescent protein (EGFP) fusion gene into Huh 7 cells. mRNA expressions of these genes were evaluated by RT-PCR analysis. The functions of hNIS and HSV1-sr39tk were verified with (125)I uptake and (3)H-penciclovir (PCV) uptake tests. EGFP and hNIS expression was confirmed with confocal microscopy after immunocytochemical staining. We treated the tumor cells with ANT2 shRNA or GCV or both ANT2 shRNA and GCV and treated the in vivo mouse model with a Huh 7/NTG tumor xenograft. The therapeutic effects of the in vivo study were assessed with caliper measurements and gamma camera imaging using (99m)Tc-pertechnetate. Huh 7/NTG cells showed a cell number-dependent increase in (125)I uptake and a 24-fold higher (3)H-PCV uptake compared to parent Huh 7 cells. Huh 7/NTG cells transfected with ANT2 shRNA had lower ANT2 mRNA expression and more impaired proliferation activity than cells transfected with scramble shRNA. Proliferation of Huh 7/NTG cells was also inhibited by GCV treatment. Combined GCV and ANT2 shRNA therapy further inhibited cell proliferation in the in vitro study. The combined therapy with GCV and ANT2 shRNA showed a further decrease in tumor growth in the mouse model. Our results suggest that the combined RNA interference with ANT2 and GCV therapy inhibited hepatocellular carcinoma cell proliferation more than single GCV therapy or ANT2 shRNA therapy in vitro and in vivo. Therefore it could be applied treating incurable hepatocellular carcinoma.

Reduction of Transplant Arteriosclerosis After Treatment With Mycophenolate Mofetil and Ganciclovir in a Mouse Aortic Allograft Model

Transplant arteriosclerosis is a major obstacle for long-term allograft survival in heart transplant. The aim of this study was to investigate potential synergistic effects of combined treatment with mycophenolate mofetil and ganciclovir on the development of transplant arteriosclerosis, presence of regulatory T cells, and expression of donor specific alloantibodies. Donor aortas from C57BL/6 (H2b) mice that were fully mismatched to the major histocompatibility complex were transplanted into CBA (H2k) mouse recipients. Groups of mice received mycophenolate mofetil (100 or 300 mg/kg, oral), ganciclovir (10 or 72 mg/kg, intraperitoneal), or a mycophenolate mofetil and ganciclovir combination. Grafts were analyzed by histology and morphometry on day 30 after transplant. Numbers of regulatory T cells and donor-specific alloantibodies were examined by fluorescence-activated cell sorting analysis of splenic tissue and peripheral blood. Mycophenolate mofetil (100 mg/kg) and ganciclovir (10 mg/kg and 72 mg/kg) did not show effects on transplant arteriosclerosis formation or alloantibody production. However, groups treated with mycophenolate mofetil (300 mg/kg) or a low- or high-dose mycophenolate mofetil and ganciclovir combination had significantly reduced transplant arteriosclerosis and alloantibody levels. Expression of regulatory T cells within the spleen was similar between all experimental groups and untreated controls. The combination of mycophenolate mofetil and ganciclovir significantly reduced the development of transplant arteriosclerosis in a mouse abdominal aortic allograft model. This effect may be a result of decreased alloantibody production.

Synergistic effect of scopadulciol in treating human prostate cancer by TK-dependent ganciclovir

Objective To investigate the synergistic efect of scopadulciol (SDC) on the killing effect on antitumor actions by Ad-hTERT-HSV-tk/ganciclovir (GCV) suicide gene system on prostate cancer cells in vitro.Methods To clarify the mechanism of enhanced effect of SDC in the gene therapy of human prostate cancer by TK-dependent GCV in molecular level,the TK enzyme activity and the concentration of GCV-TP in the tumor cells were measured by using high performance liquid chromatography (HPLC).The prostate cancer cells,respectively,were treated with Ad-hTERT-HSV-tk or GCV in combination with SDC with different doses and different concentrations.The killing effect and the bystander effect of these drugs in the therapy of human prostate cancer cells were observed.Results SDC had slightly effect on the TK enzyme activity of LNCaP and PC3 cells that were transduced by Ad-hTERT-HSV-tk.The GCV-TP concentration in the GCV treatment group was 100％.The GCV-TP concentration was ( 101.0 ± 1.5) ％ when 0.04 μmol/L SDC was added,but there was no significant difference.The GCV-TP concentration was up to ( 106.0 ± 4.5) ％ when adding 0.20 μmol/L SDC that was 5-fold higher for the dose of the therapy,and there was significant difference campared to the GCV treatment group (P＜0.05).It was confirmed that SDC had strong bystander effect and weak killing effect on the prostate cancer cells by conbination of Ad-hTERT-HSV-tk and GCV.Conclusion The synergistic effect of SDC is significantly shown in the therapy of human prostate cancer cells by TK-dependent GCV.SDC is effective in the Ad-hTERT-HSV-tk/GCV administration system in killing prostate cancer cells. Key words: Prostate cancer; Gene therapy; Recombinant adenovirus; Telomerase reverse transcriptase

Abstract 2760: Gemcitabine induced lytic EBV replication and confers ganciclovir susceptibility to EBV-positive gastric cancer

Abstract Epstein-Barr virus (EBV) is a dsDNA human gamma herpes virus which infects more than 90% of human populations. It is associated with the development of malignancies such as Burkitt's lymphoma, nasopharyngeal carcinoma, and EBV-associated gastric carcinoma. Gastric cancer is the second most common cancer in the world and the highest incidence is in Korea. The constant presence of the viral genome in EBV associated gastric cancer tissue offers the potential for novel EBV targeted therapies using antiviral nucleoside drug. Ganciclovir (GCV) is the drug of choice in herpes virus infection, however, GCV alone have been unsuccessful in the treatment of EBV associated malignancies because the virus maintains a latent state of replication in tumor, and thymidine kinase (BXLF1) and protein transferase (BGLF4), express only during lytic state of replication. In recent years, novel treatment strategies are being investigated where in lytic replication of the virus in EBV associated cancer is induced prior to the use of GCV. We investigate Gemcitabine (Gem), which is one of newly discovered potential lytic inducers found from FDA approved drug library screen using BZLF1 promoter reporter system. We examined whether the combination of GCV and Gem is more effective than Gem alone for killing EBV-positive gastric cancer cells. We found GCV significantly enhanced the ability of Gem to kill EBV-positive, but not EBV negative, gastric carcinoma cells in vitro. Also we found that low dose (2.5ng/ml) and short term exposures (24hr) of the EBV positive gastric cancer cell line SNU719 to Gem induced expression of the EBV lytic phase proteins. Viral kinases were also induced by short term and low dose exposure. Short term and low dose exposure to Gem in combination with GCV induced tumor cell death and cell proliferation inhibition. In conclusion, pharmacologic induction of the lytic viral kinases in tumor cells using Gem, followed by treatment with GCV is useful in EBV associated gastric cancer in vitro. And this virus-targeted antitumor strategy may provide a new therapeutic approach to EBV-associated gastric cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2760. doi:1538-7445.AM2012-2760

Investigation of Anti-EBV Activity of Ganciclovir in Combination with Antiflogistics

Investigation of Anti-EBV Activity of Ganciclovir in Combination with Antiflogistics

Abstract 5374: Synergistic tumor cell killing with ganciclovir and vorinostat is due to inhibition of homologous recombination

Abstract The indiscriminate nature of traditional cancer chemotherapy, which targets all dividing cells, has initiated a search for more selective approaches such as suicide gene therapy. With this strategy, only the cells containing the suicide gene are capable of activating a prodrug to a toxic metabolite, thus conferring selectivity for tumor cells while sparing normally dividing tissues. One of the most commonly used suicide gene therapy strategies transfers the cDNA for herpes simplex virus thymidine kinase (HSV-TK) into tumor cells followed by treatment with the antiviral drug ganciclovir (GCV). GCV is phosphorylated initially by HSV-TK, and after further phosphorylation by cellular kinases the active triphosphate is incorporated into the DNA of dividing cells. Recently, we have demonstrated a role for homologous recombination (HR) repair in promoting survival after treatment of GCV in HSV-TK containing cells. Based on these findings, we hypothesize that pharmacologic inhibition of HR will result in synergistic cell kill when combined with GCV. Previous reports have demonstrated that inhibition of lysine deacetylases (KDACs) can inhibit HR. KDACs can also increase the expression of the cell receptor utilized by adenoviruses for infection, thus making this class of drugs a potentially beneficial addition to gene therapy with HSV-TK/GCV. Therefore we evaluated the effect of the KDAC inhibitor Vorinostat (SAHA) on HR and cytotoxicity with HSV-TK/GCV. The ability of SAHA to inhibit HR was evaluated in a cell based recombination reporter assay. SAHA (1 to 10µM) produced increasing inhibition (51 to 85%) of HR. Western blot analysis demonstrated that these concentrations of SAHA produced a dose-dependent decrease in Rad51, an essential protein for HR. HR can be visualized in intact cells by the formation of Rad51 foci at sites of DNA damage. In U251tk cells (stably expressing HSV-TK), GCV produced a time-dependent increase in Rad51 foci, demonstrating a role for HR in repair of GCV-induced DNA damage. At concentrations that inhibited HR and decreased Rad51 expression, SAHA completely blocked Rad51 foci formation with GCV treatment. Together, these data demonstrate that SAHA inhibits HR in response to GCV. We then evaluated cytotoxicity with the combination of GCV and SAHA and observed a synergistic increase in cell kill. To further assess the role of HR in the synergistic cytotoxicity with SAHA and GCV, we evaluated the drug combination in HR proficient and deficient CHO cells stably expressing HSV-TK. The results demonstrated that the combination of SAHA and GCV produced synergistic cell kill in HR proficient cells but only additive cell kill in HR deficient cells. Collectively, these data demonstrate that inhibition of HR by SAHA can account, at least in part, for the synergistic cytotoxicity with GCV. These data suggest that the combination of SAHA and HSV-TK/GCV merits further evaluation in vivo. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5374. doi:10.1158/1538-7445.AM2011-5374

Reduced transplant arteriosclerosis after treatment with MMF and MMF in combination with ganciclovir in a mouse aortic transplant model

Objectives: The aim of this study was to investigate whether Ganciclovir and Mycophenolate Mofetil (MMF), alone and in combination, have a beneficial influence on the development of transplant arteriosclerosis (TxA). Methods: Fully allogeneic C57BL/6 (H2b) donor aortas were transplanted into CBA (H2k) recipients. Recipient mice were treated with a single medication of MMF (100mg/kg or 300mg/kg) or a combination of MMF and Ganciclovir (10mg/kg Ganciclovir and 100mg/kg MMF or 72mg/kg Ganciclovir and 300mg/kg MMF) per day. Grafts were analysed by histology and morphometry on day 30 after transplantation. A potential effect of MMF or Ganciclovir on Tregs was investigated by FACS analysis. Results: Two doses of 150mg/kg MMF per day significantly reduced the development of TxA compared to untreated controls (intima proliferation of 23%±8% vs. 68%±7% [control]). 50mg/kg of MMF did not have any effect on the development of TxA. Strikingly, combination of Ganciclovir and low-dose MMF reduced the formation of TxA (intima proliferation of 27%±2% vs. 68%±7% [control]). The high-dose combination group (300mg MMF/72mg Ganciclovir) showed an intima proliferation of 24%±4%. FACS analysis of the spleen within this group revealed 12.73% CD4+cells with 14.70% CD4+CD25+FoxP3+cells. As compared to 17.5% CD4+cells with 11.1% CD4+CD25+FoxP3+cells in the control group. Single treatment with MMF (300mg) showed 10.55% CD4+ cells and 10.87% CD4+CD25+FoxP3+ cells within the analysed spleens. Conclusion: Our results demonstrate a dose-dependent positive effect of MMF on the development of TxA and a synergistic effect of Ganciclovir in combination with MMF.

Ganciclovir and Leflunomide Combination Therapy for a Patient with Cytomegalovirus Pneumonia after Unrelated Allogenic Stem Cell Transplantation

Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality among transplant recipients. The first line standard therapy for CMV pneumonia is treatment with a combination of ganciclovir and immunoglobulin. Nevertheless, the mortality of CMV pneumonia is 30-70%. Leflunomide has been recently reported to have novel anti-CMV activity by inhibiting viron assembly. It is also cheaper and is more easily given orally as compared to ganciclovir. We report here on an allogenic stem cell transplant recipient who developed CMV pneumonia that was refractory to ganciclovir and immunoglobulin. The patient was successfully treated with a combination of leflunomide and ganciclovir.

Interfering with cellular signaling pathways enhances sensitization to combined sodium butyrate and GCV treatment in EBV-positive tumor cells

The combination of sodium butyrate (NaB) and ganciclovir (GCV) was considered to be a noteworthy therapeutic strategy in Epstein-Barr virus (EBV)-associated cancers. However, clinical studies have indicated that an extremely high dose of NaB is required to obtain the expected curative efficacy. This obviously limits the practical clinical application of the two drugs combined. In this study, we investigated the possibility of sensitizing tumor cells to NaB and GCV mediated cytotoxicity by modulating intracellular signal pathways. The results showed that the disruption of Ras/Raf activity by expressing dominant negative forms of both Ras and Raf-1 did not alter the potency of the NaB and GCV combination in the EBV-positive cell line, B95-8. However, blocking Akt activity by expressing its dominant negative form remarkably promoted NaB and GCV-mediated cytotoxicity via a thymidine kinase (TK)-independent mechanism. Interestingly, it was found that the constitutive activation of mitogen-activated protein kinase kinase kinase 1 (MEKK1) dramatically enhanced the sensitization of the cells to the combination of NaB and GCV, accompanied with an increase in TK expression in B95-8 cells. These results suggest that interfering with either the Akt or MEKK1 signaling pathway may be a useful therapeutic strategy to increase the sensitivity of EBV-positive tumor cells to the combination of NaB and GCV.

Adenovirus-mediated herpes simplex virus thymidine kinase gene transfer driver by KDR promoter in treatment of experimental human hepatocelLular carcinoma in nude mice

To investigate the therapeutic efficacy of adenovirus-mediated herpes simplex virus thymidine kinase (HSV-tk) gene transfer under the driving of KDR promoter (AdKDR-tk) in combination of ganciclovir (GCV) against human hepatocellular carcinoma in nude mice. HepG2 cell line was implanted subcutaneously into 32 nude mice, which were subsequently divided into 4 groups (n=8 each group): Ganciclovir group (I), Ad group (II), AdCMV-tk/GCV group (under the driving of CMV promoter) (III) and AdKDR-tk/GCV group (IV). Then intratumoral injection of recombinant adenovirus or Ad was performed in all nude mice, and repeated 24 h later. For the following 10 d GCV was given at a dose of 100 mg/(kg·d), ip. All the treated animals were killed to evaluate the tumor weight and the histopathological changes and the microvessel density of tumors after the treatment was determined. Compared with group I, the tumor inhibitory rate was 12.3% in group III and 24.5% in group IV; the inhibition rates were significantly different between group III and IV (P<0.05). The mean MVDs in group I, II, III and IV were 37.4±8.6, 30.6±7.8, 27.6±7.1, and 10.7±4.1 (microvessels/mm2), respectively. Significant differences were found between group III and II (P<0.05), IV and II (P<0.01), and IV and III (P<0.01). Intratumoral injection of AdKDR-tk results in marked inhibition of HCC growth through inhibition angiogenesis in nude mice. It may be a new treatment approach for human HCC.

Leflunomide failure to control recurrent cytomegalovirus infection in the setting of renal failure after allogeneic stem cell transplantation

Cytomegalovirus (CMV) reactivation is common in the allogeneic stem cell transplant setting but the incidence of CMV organ disease and mortality has been dramatically reduced by prophylactic or preemptive antiviral therapy. We report the case of a CMV-seropositive 46-year-old man with non-Hodgkin's lymphoma who underwent an unrelated allogeneic stem cell transplant from a CMV-seronegative HLA-matched unrelated donor. CMV encephalitis and colitis developed that was refractory to single-agent therapy. The CMV isolate demonstrated genotypic resistance to both ganciclovir and foscarnet. CMV disease was controlled by prolonged combination ganciclovir and cidofovir therapy, but severe renal dysfunction developed. Leflunomide was selected as a last resort to avoid the nephrotoxicity of cidofovir. CMV antigenemia rapidly increased following leflunomide administration, necessitating discontinuing this agent and resuming prior antiviral therapy. The pharmacokinetics of leflunomide in the setting of renal insufficiency is presented. Options for salvage therapy in refractory CMV disease in allogeneic stem cell transplant recipients are briefly reviewed.