Oncolytic adenoviruses for treatment of ovarian cancer

Virotherapy, the use of oncolytic properties of viruses for eradication of tumor cells, is an attractive strategy for treating cancers resistant to traditional modalities. Adenoviruses can be genetically modified to selectively replicate in and destroy tumor cells through exploitation of molecular differences between normal and cancer cells. The lytic life cycle of adenoviruses results in oncolysis of infected cells and spreading of virus progeny to surrounding cells. In this study, we evaluated different strategies for improving safety and efficacy of oncolytic virotherapy against human ovarian adenocarcinoma. We examined the antitumor efficacy of Ad5/3-Δ24, a serotype 3 receptor-targeted pRb-p16 pathway-selective oncolytic adenovirus, in combination with conventional chemotherapeutic agents. We observed synergistic activity in ovarian cancer cells when Ad5/3-Δ24 was given with either gemcitabine or epirubicin, common second-line treatment options for ovarian cancer. Our results also indicate that gemcitabine reduces the initial rate of Ad5/3-Δ24 replication without affecting the total amount of virus produced. In an orthotopic murine model of peritoneally disseminated ovarian cancer, combining Ad5/3-Δ24 with either gemcitabine or epirubicin resulted in greater therapeutic benefit than either agent alone. Another useful approach for increasing the efficacy of oncolytic agents is to arm viruses with therapeutic transgenes such as genes encoding prodrug-converting enzymes. We constructed Ad5/3-Δ24-TK-GFP, an oncolytic adenovirus encoding the thymidine kinase (TK) green fluorescent protein (GFP) fusion protein. This novel virus replicated efficiently on ovarian cancer cells, which correlated with increased GFP expression. Delivery of prodrug ganciclovir (GCV) immediately after infection abrogated viral replication, which might have utility as a safety switch mechanism. Oncolytic potency in vitro was enhanced by GCV in one cell line, and the interaction was not dependent on scheduling of the treatments. However, in murine models of metastatic ovarian cancer, administration of GCV did not add therapeutic benefit to this highly potent oncolytic agent. Detection of tumor progression and virus replication with bioluminescence and fluorescence imaging provided insight into the in vivo kinetics of oncolysis in living mice. For optimizing protocols for upcoming clinical trials, we utilized orthotopic murine models of ovarian cancer to analyze the effect of dose and scheduling of intraperitoneally delivered Ad5/3-Δ24. Weekly administration of Ad5/3-Δ24 did not significantly enhance antitumor efficacy over a single treatment. Our results also demonstrate that even a single intraperitoneal injection of only 100 viral particles significantly increased the survival of mice compared with untreated animals. Improved knowledge of adenovirus biology has resulted in creation of more effective oncolytic agents. However, with more potent therapy regimens an increase in unwanted side-effects is also possible. Therefore, inhibiting viral replication when necessary would be beneficial. We evaluated the antiviral activity of chlorpromazine and apigenin on adenovirus replication and associated toxicity in fresh human liver samples, normal cells, and ovarian cancer cells. Further, human xenografts in mice were utilized to evaluate antitumor efficacy, viral replication, and liver toxicity. Our data suggest that these agents can reduce replication of adenoviruses, which could provide a safety switch in case of replication-associated side-effects. In conclusion, we demonstrate that Ad5/3-Δ24 is a useful oncolytic agent for treatment of ovarian cancer either alone or in combination with conventional chemotherapeutic drugs. Insertion of genes encoding prodrug-converting enzymes into the genome of Ad5/3-Δ24 might not lead to enhanced antitumor efficacy with this highly potent oncolytic virus. As a safety feature, viral activity can be inhibited with pharmacological substances. Clinical trials are however needed to confirm if these preclinical results can be translated into efficacy in humans. Promising safety data seen here, and in previous publications suggest that clinical evaluation of the agent is feasible.Ei saatavill

Technetium-99m-labeled nanofibrillar cellulose hydrogel for in vivo drug release

Peer reviewe

Subacute administration of both methcathinone and manganese causes basal ganglia damage in mice resembling that in methcathinone abusers

An irreversible extrapyramidal syndrome occurs in man after intravenous abuse of "homemade" methcathinone (ephedrone, Mcat) that is contaminated with manganese (Mn) and is accompanied by altered basal ganglia function. Both Mcat and Mn can cause alterations in nigrostriatal function but it remains unknown whether the effects of the 'homemade' drug seen in man are due to Mcat or to Mn or to a combination of both. To determine how toxicity occurs, we have investigated the effects of 4-week intraperitoneal administration of Mn (30 mg/kg t.i.d) and Mcat (100 mg/kg t.i.d.) given alone, on the nigrostriatal function in male C57BL6 mice. The effects were compared to those of the 'homemade' mixture which contained about 7 mg/kg of Mn and 100 mg/kg of Mcat. Motor function, nigral dopaminergic cell number and markers of pre- and postsynaptic dopaminergic neuronal integrity including SPECT analysis were assessed. All three treatments had similar effects on motor behavior and neuronal markers. All decreased motor activity and induced tyrosine hydroxylase positive cell loss in the substantia nigra. All reduced I-123-epidepride binding to D2 receptors in the striatum. Vesicular monoamine transporter 2 (VMAT2) binding was not altered by any drug treatment. However, Mcat treatment alone decreased levels of the dopamine transporter (DAT) and Mn alone reduced GAD immunoreactivity in the striatum. These data suggest that both Mcat and Mn alone could contribute to the neuronal damage caused by the 'homemade' mixture but that both produce additional changes that contribute to the extrapyramidal syndrome seen in man.Peer reviewe

Pre-Targeting and Direct Immunotargeting of Liposomal Drug Carriers to Ovarian Carcinoma

Peer reviewe

Systemic therapy for cervical cancer with potentially regulatable oncolytic adenoviruses

Peer reviewe

Regulation of Cox-2 and VEGF promoter activity with anti-inflammatory reagents.

<p>Monolayers were preincubated with reagents, and C33A (a, b), SiHa (c, d), Caski (e, f) and HeLa (g, h) cells were infected with 1 000 viral particles (vp)/cell of Ad5luc1 (with the CMV controlling luciferase), Adcox-2Mluc or AdVEGFluc, and luciferase expression was analyzed. Transgene expression level with Cox-2 and VEGF promoters are compared to the CMV promoter (%). Each point represents the mean of four experiments±standard error. *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.0001 <i>versus</i> no substance.</p

Infectivity of cervical cancer cells by adenoviral vectors with fiber knob modifications and the effect of anti-inflammatory reagents on transduction efficacy.

<p>(a–d) Cell lines were infected with Ad5luc1, Ad5/3luc1, and Ad5lucRGD. Luciferase activity is expressed as relative light units (RLU) normalized for total protein concentration. (e–h) The effect of anti-inflammatory reagents on transduction efficacy of capsid modified adenoviruses. Cells were infected in the presence of substances. The value without reagents was set at 1, and relative luciferase values are shown. Each point represents the mean of three experiments±standard error. *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.0001 <i>versus</i> Ad5luc1.</p

Oncolytic adenoviruses display efficient killing of cervical cancer cells <i>in vitro</i> and <i>in vivo</i>.

<p>(a–d) Monolayers were infected with RGDCRADcox-2R, Ad5/3VEGF-E1, Ad5-Δ24RGD, wild-type adenovirus and Ad5luc1 (<i>E1</i>-deleted control virus). Cell viability was measured with MTS assay. The OD₄₉₀ values of uninfected cells were set as 100%. Data is expressed as mean±standard error of quadruplicate experiments. (e–f) C33A cells were injected subcutaneously into nude mice and advanced tumors were allowed to develop. The mice were treated either with (e) three intratumoral injections of 1×10⁹ viral particles (vp) of Ad5luc1, wild-type virus or oncolytic adenoviruses on three consecutive days, or with (f) a single intravenous injection of 1×10¹¹ vp. *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.0001 <i>versus</i> Ad5luc1. Bars indicate standard error.</p