hygromycin-a and Brain-Neoplasms

A variant of C6 glioma cells, C6R-G/H cells express hygromycin phosphotransferase (HPT) and appear to have reduced tumorigenicity in the embryonic brain. The goal of this study was to investigate their reduced capacity to generate tumors in the adult rat brain.. Cell lines were implanted into rat brains and tumorigenesis was evaluated. After 3 weeks, all rats with C6 cells showed signs of neurological disease, whereas rats with C6R-G/H cells did not and were either killed then or allowed to survive until later. Histological studies were performed to analyze tumor size, malignancy, angiogenesis, and cell proliferation. Cells isolated from rat brain tumors were analyzed for mutation to HPT by testing their sensitivity to hygromycin.. The results indicate that HPT suppresses tumor formation. Three weeks after implantation, only 44% of animals implanted with C6R-G/H cells developed tumors, whereas all animals that received C6 glioma cells developed high-grade gliomas. The C6R-G/H cells filled a 20-fold smaller maximal cross-sectional area than the C6 cells, and exhibited less malignant characteristics, including reduced angiogenesis, mitosis, and cell proliferation. Similar results were obtained in the brain of nude rats, indicating that the immune system did not play a significant role in suppressing tumor growth. The combination of green fluorescent protein (GFP) and HPT was more effective in suppressing tumorigenesis than either plasmid by itself, indicating that the GFP may protect against inactivation of the HPT. Interestingly. hygromycin resistance was lost in tumor cells that were recovered from a group of animals in which C6R-G/H cells formed tumors, confirming the correlation of HPT with reduced tumorigenicity.

Topics: Animals; Brain Neoplasms; Cell Division; Cinnamates; Drug Resistance; Female; Genes, Tumor Suppressor; Glioma; Graft Rejection; Green Fluorescent Proteins; Hygromycin B; Luminescent Proteins; Mitosis; Mutation; Neoplasm Transplantation; Neovascularization, Pathologic; Phenotype; Phosphotransferases (Alcohol Group Acceptor); Rats; Rats, Inbred WKY; Rats, Nude; Recombinant Fusion Proteins; Transfection; Tumor Cells, Cultured

A large animal tumor model for anaplastic glioma has been recently developed using immunotolerant allogeneic Beagle dogs and an established canine glioma cell line, J3T. This model offers advantages in terms of tumor morphology and similarity to human anaplastic glioma. The present study was aimed at evaluating the biological characteristics of the J3T canine glioma cell line as related to experimental gene therapy studies. Furthermore, development and morphology of canine brain tumors in a xenogeneic immunodeficient SCID mouse model was investigated. It was demonstrated that cultured J3T cells can be efficiently infected by adenovirus (AV), herpes-simplex type I (HSV), or retrovirus (RV) vectors, as well as by non-virus vectors such as cationic liposome/DNA complexes. Thus, in terms of infectability and transfectability, J3T cells seem to be closer to human glioma than the 9L rodent gliosarcoma. Cytotoxicity of selection antibiotics such as G418, puromycin, and hygromycin on J3T cells essentially resemble cytotoxicity seen with other established glioma lines, for example, 9L, U87, or U343. RV-mediated HSV-TK/GCV gene therapy demonstrated comparable LD50 for TK-expressing and control (non-expressing) J3T and 9L cells treated with Ganciclovir. Further, it was proven that J3T cells are tumorigenic and may grow heterotopically and orthotopically in a xenogeneic immunodeficient host, the SCID mouse, although morphology and growth pattern of these xenogeneic tumors differ from the demonstrated invasive phenotype in the Beagle dog.

Topics: 3T3 Cells; Adenoviridae; Animals; Anti-Bacterial Agents; Antiviral Agents; Brain Neoplasms; Cell Culture Techniques; Cell Division; Chlorocebus aethiops; Cinnamates; Dogs; Drug Resistance, Microbial; Ganciclovir; Gene Expression Regulation, Neoplastic; Gene Expression Regulation, Viral; Gene Transfer Techniques; Genetic Therapy; Glioblastoma; Gliosarcoma; Herpesvirus 1, Human; Humans; Hygromycin B; Kidney; Male; Mice; Mice, SCID; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Thymidine Kinase; Tumor Cells, Cultured; Vero Cells