For a long time past viruses have been recognized as being tumoricidal. At present, researchers are still pursuing studies and constructing more suitable oncolytic viruses for treating different malignant tumors. Herpes simplex virus type 1 (HSV-1) has been known as the most potential oncolytic virus among all the viruses. In this overview, we summarize the current situation of oncolytic viruses, the biology of HSV-1, its construction and application of its recombinant, and we debate on the feasibility and prospect of HSV-1 mutants labeled with radionuclides for cancer therapy.
Herpesvirus 1, Human ; genetics ; physiology ; Humans ; Mutation ; Neoplasms ; radiotherapy ; Oncolytic Virotherapy ; methods ; trends ; Oncolytic Viruses ; genetics

Naturally existing Newcastle disease virus (NDV) can specifically execute oncolytic ability in clinical studies. Reports from clinical trials using NDV as oncolytic agents showed promise and warrant results in cancer therapy. In recent years, reverse genetics technology has been used widely in the studies of NDV virology. More recently, the technology was applied to optimize the oncolytic efficacy of NDV, for instance, modification of the F gene, and expression of GM-CSF, IFN-gamma, IL-2 or TNF-alpha. NDV is widely investigated in cancer therapy and will definitely offer a prosperous future for clinical cancer therapeutics. We reviewed the developments of cancer therapy by recombinant NDV using reverse genetics technology, as well as our own experience in this domain.
Animals ; Humans ; Neoplasms ; pathology ; therapy ; Newcastle disease virus ; genetics ; physiology ; Oncolytic Virotherapy ; methods ; Oncolytic Viruses ; genetics ; physiology ; Recombination, Genetic

In this research was developed high efficiency method using 125I for directly labeling KH901, a tumor-specific oncolytic recombinant adenovirus, biodistribution of 125I-labeled compound in normal mice was investigated. 125I-KH901 was prepared by N-bromosuccinimide labeling method to find the optimal ratio of labeling response. The compounds were isolated and purified by Sephadex-G10 agarose and the radiochemical purity of compounds was analyzed by paper chromatography. The radioactivity biodistribution in mice was measured at different times after caudal vein injection with 0.1ml 125I-KH901. The labeling yield of 125I-KH901 was 78% and the radiochemical purity was 95% after purification by Sephadex-G10 agarose. Biodistribution revealed that the uptake of 125I-KH901 in liver was higher than in other organs at all time points of the experiment. 125I-KH901 was mainly concentrated in liver, kidneys, spleen and lung. It can be seen that N-bromosuccinimide labeling method is an optimal method with simple steps and high labeling yield in labeling KH901 with 125I. 125I-KH901 has a biodistribution trait which is an advantage to treating liver tumors.
Adenoviridae ; genetics ; physiology ; Animals ; DNA, Recombinant ; genetics ; Female ; Genetic Vectors ; genetics ; Iodine Radioisotopes ; pharmacokinetics ; Male ; Mice ; Mice, Inbred BALB C ; Oncolytic Viruses ; genetics ; physiology

The E1A gene was obtained by PCR with QBI-293A cell genome DNA as template. After enzyme digestion, the E1A gene was ligated to transfer vector pAdTrack-CMV. The positive clone pAdTrack-CMV-E1A were lineared by PmeI and co-transformed with pAdEasy-1 in BJ5183 E. coli. The recombinant adenovirus vector pAdEasy-1-pAdTrack-CMV-E1A were digested by PacI and transfected into QBI-293A cells with liposomes. The oncolytic recombinant adenovirus Ad-E1A was obtained after 7 days. The results showed that this oncolytic adenovirus Ad-E1A can replicate in ECV304 cells and inhibit growth of ECV304 cell. In addition, it also decreased the secretion of VEGF and expression of NF-kappaB of ECV304 cells, indicating that Ad-E1A have potential of inhibition of tumor metastasis.
Adenoviridae ; genetics ; physiology ; Adenovirus E1A Proteins ; biosynthesis ; genetics ; Cell Proliferation ; Cells, Cultured ; Endothelial Cells ; cytology ; metabolism ; Humans ; Oncolytic Virotherapy ; Oncolytic Viruses ; genetics ; physiology ; Promoter Regions, Genetic ; Umbilical Veins ; cytology ; metabolism

To establish a detection method of oncolytic adenovirus/p53 and standard of quality control, human telomerase reverse transcriptase (hTERT) promoter, CMV fusion promoter containing hypoxia reaction element (HRE) and p53 gene were identified by vector DNA restriction enzyme digestion and PCR analysis. The result conformed that all modified regions were in consistent with theoretical ones. Particle number was 2.0 x 10(11) mL(-1) determined by UV (A260). Infectious titer was 5.0 x 10(10) IU mL(-1) analyzed by TCID50. In vitro p53 gene expression in human lung cancer cell H1299 was determined by ELISA, and A450 ratio of nucleoprotein in virus infection group to control group was 5.2. Antitumor potency was evaluated by cytotoxicity assay using human lung cancer cell A549, and the MOI(IC50) of this gene therapy preparation was 1.0. The tumor cells targeted replication ability of recombinant virus was determined by TCID50 titer ratio of filial generation virus between human lung cancer cell A549 and human diploid epidermal fibrolast BJ cells after infected by virus with same MOI. TCID50 titer ratio of tumor cell infection group to normal cell infection control group was 398. The IE-HPLC purity of virus was 99.5%. There was less than 1 copy of wild type adenovirus within 1 x 10(7) VP recombinant virus. Other quality control items were complied with corresponding requirements in the guidance for human somatic cell therapy and gene therapy and Chinese pharmacopeia volume III. The detection method of oncolytic adenovirus/p53 was successfully established for quality control standard. The study also provided reference for quality control of other oncolytic viral vector products.
Adenoviridae ; genetics ; metabolism ; physiology ; Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Genes, p53 ; Genetic Therapy ; Genetic Vectors ; Humans ; Neoplasms ; metabolism ; pathology ; virology ; Oncolytic Viruses ; genetics ; metabolism ; physiology ; Quality Control ; Recombinant Fusion Proteins ; genetics ; metabolism ; Transfection ; Virus Replication

PURPOSE: We have used a genetically attenuated adenoviral vector which expresses HSVtk to assess the possible additive role of suicidal gene therapy for enhanced oncolytic effect of the virus. Expression of TK was measured using a radiotracer-based molecular counting and imaging system. MATERIALS AND METHODS: Replication-competent recombinant adenoviral vector (Ad-deltaE1B19/55) was used in this study, whereas replication-incompetent adenovirus (Ad-deltaE1A) was generated as a control. Both Ad-deltaE1B19/55-TK and Ad-deltaE1A-TK comprise the HSVtk gene inserted into the E3 region of the viruses. YCC-2 cells were infected with the viruses and incubated with 2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl-5-iodouracil (I-131 FIAU) to measure amount of radioactivity. The cytotoxicity of the viruses was determined, and gamma ray imaging of HSVtk gene was performed. MTT assay was also performed after GCV treatment. RESULTS: On gamma counter-analyses, counts/minute (cpm)/microgram of protein showed MOIs dependency with deltaE1B19/55-TK infection. On MTT assay, Ad-deltaE1B19/55-TK led to more efficient cell killing than Ad-deltaE1A-TK. On plate imaging by gamma camera, both Ad-deltaE1B19/55-TK and Ad-deltaE1A-TK infected cells showed increased I-131 FIAU uptake in a MOI dependent pattern, and with GCV treatment, cell viability of deltaE1B19/55-TK infection was remarkably reduced compared to that of Ad-deltaE1A-TK infection. CONCLUSION: Replicating Ad-deltaE1B19/55-TK showed more efficient TK expression even in the presence of higher-cancer cell killing effects compared to non-replicating Ad-deltaE1A-TK. Therefore, GCV treatment still possessed an additive role to oncolytic effect of Ad-deltaE1B19/55-TK. The expression of TK by oncolytic viruses could rapidly be screened using a radiotracer-based counting and imaging technique.
Adenoviridae/*genetics/physiology ; Cell Line, Transformed ; Cell Line, Tumor ; Ganciclovir/pharmacology ; Gene Expression ; Gene Therapy/methods ; Genetic Vectors ; Humans ; *Oncolytic Virotherapy ; Oncolytic Viruses/*genetics/physiology ; Simplexvirus/genetics ; Tetrazolium Salts/analysis ; Thiazoles/analysis ; Thymidine Kinase/*genetics/metabolism ; Transgenes ; Viral Proteins/*genetics/metabolism ; Virus Replication

OBJECTIVEThe aim of this study was to construct a new oncolytic virus oHSV2hGM-CSF and evaluate its oncolytic activity in vitro and in vivo in parallel with oHSV1hGM-CSF.

METHODSoHSV2hGM-CSF was a replication-competent, attenuated HSV2 based on the HG52 virus (an HSV2 strain). It was engineered to be specific for cancer by deletion of the viral genes ICP34.5 and ICP47 and insertion of the gene encoding hGM-CSF. To measure the in vitro killing effect of the virus, 15 human tumor cell lines (HeLa, Eca-109, PG, HepG2, SK/FU, CNE-2Z, PC-3, SK-OV3, A-549, 786-0, MCF-7, Hep-2, HT-29, SK-Mel-28, U87-MG) and mouse melanoma (B16R) cell line were seeded into 24-well plates and infected with viruses at MOI = 1 (multiplicity of infection, MOI), or left uninfected. The cells were harvested 24 and 48 hours post infection, and observed under the microscope. For animal studies, the oncolytic viruses were administered intratumorally (at 3-day interval) at a dose of 2.3 x 10(6) PFU (plaque forming unit, PFU) for three times when the tumor volume reached 7-8 mm3. The tumor volume was measured at 3-day intervals and animal survival was recorded.

RESULTSBoth oHSV2hCM-CSFand oHSV1hGM-CSF induced widespread cytopathic effects at 24 h after infection. OHSV2hGM-CSF, by contrast, produced more plaques with a syncytial phenotype than oHSV1hGM-CSF. In the in vitro killing experiments for the cell lines HeLa, HepG2, SK-Mel-28, B16R and U87-MG, oHSV2hGM-CSF eradicated significantly more cells than oHSV1hGM-CSF under the same conditions. For the mouse experiments, it was observed that oHSV2hGM-CSF significantly inhibited the tumor growth. At 15 days after B16R tumor cells inoculation, the tumor volumes of the PBS, oHSV1hGCM-CSF and oHSV2hGM-CSF groups were (374.7 +/- 128.24) mm3, (128.23 +/- 45.32) mm3 (P < 0.05, vs. PBS group) or (10.06 +/- 5.1) mm3 (P < 0.01, vs. PBS group), respectively (mean +/- error). The long term therapeutic effect of oHSV2hGM-CSF on the B16R animal model was evaluated by recording animal survival over 110 days after tumor cells inoculation whereas all the mice in the PBS group died by day 22 (P < 0.01). The anti-tumor mechanism of the newly constructed oHSV2hGM-CSF against B16R cell tumor appeared to include the directly oncolytic activity and the induction of anti-tumor immunity to some degree.

CONCLUSIONThe findings of our study demonstrate that the newly constructed oHSV2hGM-CSF has potent anti-tumor activity in vitro to many tumor cell lines and in vive to the transplanted B16R tumor models.

Animals ; Cell Line, Tumor ; Female ; Gene Deletion ; Genetic Engineering ; Granulocyte-Macrophage Colony-Stimulating Factor ; genetics ; Herpesvirus 2, Human ; genetics ; immunology ; Humans ; Immediate-Early Proteins ; genetics ; metabolism ; Melanoma, Experimental ; pathology ; therapy ; virology ; Mice ; Mice, Inbred C57BL ; Oncolytic Virotherapy ; methods ; Oncolytic Viruses ; genetics ; physiology ; Random Allocation ; Tumor Burden ; Viral Proteins ; genetics ; metabolism ; Xenograft Model Antitumor Assays

OBJECTIVETo study the effect of CEA gene regulation on the anti-tumor activity of oncolytic adenovirus H101 to esophageal carcinoma, and to explore the intrinsic factors influencing H101 sensitivity.

METHODSStable human esophageal cancer cell line EC9706 cells with lower (EC9706-SCEA) and higher CEA expression (EC9706-CEA) were chosen, thawed and cultured, and then to analyse the influence of CEA expressed at different levels on cell growth. The cytotoxic effect of H101 was assayed by in vitro and nude mouse in vivo.

RESULTSThe cell growth experiment showed that the population doubling time of EC9706-SCEA, EC9706-CEA and EC9706 cells were (30.9 ± 2.0) h, (31.1 ± 2.5) h and (29.1 ± 2.6) h, respectively, showing no significant difference among them (P > 0.05). The cytotoxic activity of H101 was higher on EC9706-SCEA than on other four groups, when MOI was ≥ 0.01 PFU (P < 0.05). The mouse experiment showed that H101 inhibited the growth of transplanted tumors in all experimental groups. Its effect on CEA-silenced tumors (inhibition rate was 61.5% to 74.5%) was significantly higher than that on CEA-overexpression tumors (32.3% to 38.5%) and control EC9706 transplanted tumors (35.5% to 44.8%). There was a significant difference between them (P < 0.05).

CONCLUSIONSThe results in vitro and in vivo experiments show that H101 can enhance the cytotoxic effect on EC9706 cells with lower CEA expression. To silence the expression of CEA may provide a novel strategy for target gene therapy of esophageal carcinoma.

Adenoviridae ; physiology ; Animals ; Carcinoembryonic Antigen ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Esophageal Neoplasms ; metabolism ; pathology ; therapy ; Female ; Gene Silencing ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Oncolytic Virotherapy ; Oncolytic Viruses ; physiology ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Tumor Burden