Molecular docking and dynamics supported investigation of antiviral activity of Lichen metabolites of Roccella montagnei: an in silico and in vitro study.

Lichens are symbiotic organisms that have been traditionally used for treating different kinds of ailments. As there are only a few reports on the antiviral activity of lichens, we thought of evaluating the anti-Herpes simplex virus-1 (HSV-1) activity of methanolic extract of Roccella montagnei and their isolated compounds. Fractionation of crude methanolic extract of Roccella montagnei by column chromatography isolated two pure compounds. Antiviral activity was assessed using a CPE inhibition assay at non-cytotoxic concentrations on Vero cells. Molecular docking and dynamics studies were carried out against Herpes simplex type-1 thymidine kinase to understand the binding interactions of the isolated compounds with reference to acyclovir. Isolated compounds were characterized as methyl orsellinate and montagnetol by spectral methods. Methanolic extract of Roccella montagnei exhibited an EC50 value of 56.51 µg/ml, while the compounds methyl orsellinate and montagnetol offered EC50 values of 13.50 µg/ml and 37.52 µg/ml, respectively, against HSV-1 viral infection on Vero cell lines. The selectively index (SI) of montagnetol (10.93) was found to be higher when compared to that of methyl orsellinate (5.55), indicating its better anti-HSV-1 activity. The docking and dynamics studies showed montagnetol was stable throughout the 100 ns, having better interactions and docking scores with HSV-1 thymidine kinase than methyl orsellinate, as well as the standard. To understand the mechanism of montagnetol's anti-HSV-1 activity, more research is required, and this could lead to the discovery of new and effective antiviral agents.Communicated by Ramaswamy H. Sarma.

Molecular imaging-monitored radiofrequency hyperthermia-enhanced intratumoral herpes simplex virus-thymidine kinase gene therapy for rat orthotopic ovarian cancer.

Objective: To establish the technique of intratumoral combination therapy of radiofrequency hyperthermia (RFH) with herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy for rat ovarian cancers.Material and methods: This study consisted of three parts: (1) in vitro experiments to establish the 'proof of principal' that combination of RFH and HSV-TK gene therapy has the synergistic effect on human ovarian cancer cells; (2) creation of bioluminescence imaging-detectable rat ovarian cancer model; and (3) in vivo experiments using this rat model to validate the technical feasibility of the combination therapy. Cells and nude rats were divided into four groups: (i) combination therapy (HSV-TK/GCV + RFH); (ii) RFH; (iii) HSV-TK/GCV; and (iv) phosphate-buffered saline (PBS). Data were analyzed using Dunnett t-test or Kruskal-Wallis test.Results: Cell proliferation assay demonstrated significantly greater reduction in viable cells with the combination therapy [0.52 (0.43, 0.61)] compared to other treatments [RFH 0.90 (0.84, 0.96), HSV-TK/GCV 0.71 (0.53, 0.88), PBS 1 (1, 1); p < .05]. For 24 rat models with bioluminescence imaging-detectable orthotopic ovarian cancer (n = 6 per group), optical imaging demonstrated significantly decreased relative bioluminescence signal with the combination therapy [0.81 (0.52, 1.08)] compared to other treatments [RFH 3.60 (2.34, 4.86), HSV-TK/GCV 2.21 (1.71, 2.71), PBS 3.74 (3.19, 4.29); p < .001]. Ultrasound imaging demonstrated the smallest relative tumor volume with the combination therapy [0.78 (0.45, 1.11) versus 3.50 (2.67, 4.33), 2.10 (0.83, 3.37), 3.70 (1.79, 5.61); p < .05].Conclusion: The feasibility of intratumoral RFH-enhanced HSV-TK/GCV gene therapy was established on a unique rat model with molecular imaging-detectable orthotopic ovarian cancer.

The therapeutic effect of PEI-Mn0.5Zn0.5Fe2O4 nanoparticles/pEgr1-HSV-TK/GCV associated with radiation and magnet-induced heating on hepatoma.

Comprehensive therapy based on the integration of hyperthermia, radiation, gene therapy and chemotherapy is a promising area of study in cancer treatment. Using PEI-Mn(0.5)Zn(0.5)Fe(2)O(4) nanoparticles (PEI-MZF-NPs) as a gene transfer vector, the authors transfected self-prepared pEgr1-HSV-TK into HepG2 cells and measured the expression of the exogenous gene HSV-TK by RT-PCR. The results showed that HSV-TK was successfully transfected into HepG2 cells and the expression levels of HSV-TK remained stable. Besides, PEI-MZF-NPs were used as magnetic media for thermotherapy to treat hepatoma by magnet-induced heating, combined with radiation-gene therapy. Both in vitro and in vivo results suggest that this combined treatment with gene, radiation and heating has a better therapeutic effect than any of them alone. The apoptotic rate and necrotic rate of the combined treatment group was 51.84% and 15.45%, respectively. In contrast, it was only 20.55% and 6.80% in the radiation-gene group, 7.49% and 3.62% in the radiation-alone group, 15.23% and 7.90% in the heating-alone group, and only 3.52% and 2.16% in the blank control group. The inhibition rate of cell proliferation (88.5%) of the combined treatment group was significantly higher than that of the radiation-gene group (59.5%), radiation-alone group (37.6%) and heating-alone group (60.6%). The tumor volume and mass inhibition rate of the combined treatment group was 94.45% and 93.38%, respectively, significantly higher than 41.28% and 33.58% of the radiation-alone group, 60.76% and 52.18% of the radiation-gene group, 79.91% and 77.40% of the heating-alone group. It is therefore concluded that this combined application of heating, radiation and gene therapy has a good synergistic and complementary effect and PEI-MZF-NPs can act as a novel non-viral gene vector and magnetic induction medium, which offers a viable approach for the treatment of cancer.

Plant thymidine kinase 1: a novel efficient suicide gene for malignant glioma therapy.

The prognosis for malignant gliomas remains poor, and new treatments are urgently needed. Targeted suicide gene therapy exploits the enzymatic conversion of a prodrug, such as a nucleoside analog, into a cytotoxic compound. Although this therapeutic strategy has been considered a promising regimen for central nervous system (CNS) tumors, several obstacles have been encountered such as inefficient gene transfer to the tumor cells, limited prodrug penetration into the CNS, and inefficient enzymatic activity of the suicide gene. We report here the cloning and successful application of a novel thymidine kinase 1 (TK1) from the tomato plant, with favorable characteristics in vitro and in vivo. This enzyme (toTK1) is highly specific for the nucleoside analog prodrug zidovudine (azidothymidine, AZT), which is known to penetrate the blood-brain barrier. An important feature of toTK1 is that it efficiently phosphorylates its substrate AZT not only to AZT monophosphate, but also to AZT diphosphate, with excellent kinetics. The efficiency of the toTK1/AZT system was confirmed when toTK1-transduced human glioblastoma (GBM) cells displayed a 500-fold increased sensitivity to AZT compared with wild-type cells. In addition, when neural progenitor cells were used as delivery vectors for toTK1 in intracranial GBM xenografts in nude rats, substantial attenuation of tumor growth was achieved in animals exposed to AZT, and survival of the animals was significantly improved compared with controls. The novel toTK1/AZT suicide gene therapy system in combination with stem cell-mediated gene delivery promises new treatment of malignant gliomas.

Sitimagene ceradenovec, a gene therapeutic for the treatment of glioma.

Ark Therapeutics Group plc is developing sitimagene ceradenovec, a herpes simplex virus thymidine kinase/ganciclovir gene therapy utilizing an adenoviral vector, for the potential treatment of glioma. Sitimagene ceradenovec is currently undergoing a phase III clinical trial in malignant glioma patients.

New drug delivery system for water-soluble drugs using silicone and its usefulness for local treatment: application of GCV-silicone to GCV/HSV-tk gene therapy for brain tumor.

Controlled release of a water-soluble low-molecular-weight drug from silicone and its usefulness as a local therapeutic drug were studied. For application to ganciclovir/helpes simplex virus thymidine kinase (GCV/HSV-tk) suicide gene therapy for brain tumor, two kinds of GCV-containing silicone formulations were prepared for evaluation. In vitro, GCV release from matrix-type formulation consisting of a single matrix was characterized by Fickian diffusion, while covered-rod-type formulation, in which the side surface of the outer layer was covered with 100% silicone, exhibited a near-zero-order release pattern. In an in vivo study using a rat 9L glioblastoma model, administration of GCV-silicone formulation into brain tumor yielded sustained intracerebral GCV concentration for 4 days after administration, with excellent antitumor effect equal to or better than that of daily intraperitoneal administration of aqueous solution of GCV, at a dose less than 1/100 of the total dose of solution for intraperitoneal administration. Furthermore, GCV was undetectable in blood, suggesting that decrease in systemic adverse reactions can be expected with intracerebral administration of GCV-silicone formulation.