ENU administration causes genomic instability along with single nucleotide polymorphisms in p53 during gliomagenesis: T11TS administration demonstrated in vivo apoptosis of these genetically altered tumor cells

Advancement of molecular analysis of neoplastic cells demonstrated that multiple genetic changes are associated with the development of tumors. Cancer cell must exhibit a mutator phenotype, which is likely to be responsible for the genomic instability found in cancer tissues. The mutator phenotype, such as defective mismatch repair, is known to cause microsatellite instability, which is associated with certain cases of sporadic cancer. Previously many studies have been carried out to determine the relationship between microsatellite instability and human brain tumors. However information on genomic instability in the animal model of brain tumor is still very limited. In the present course of investigations we genetically characterized our ENU induced brain tumor animal model by using PCR based randomly amplified polymorphic DNA (RAPD) analysis and restriction fragment length polymorphism (RFLP) with three microsatellite probes. ENU induced tumors demonstrated genetic instability, including some microsatellite instability. As single nucleotide polymorphisms of the tumor suppressor gene p53 were associated with diverse types of human cancer, we examined the p53 gene of the tumor cells isolated from ENU induced brain tumor animal model, by PCR based RFLP method in p53 exon-2, -3 and -4. In these studies we showed that the restriction site of p53 exon-3 and 4 were mutated in ENU induced brain tumor indicating a genetic defect associated with ENU induced tumorigenesis. In the therapeutic part, we confirmed the anti-tumor property of T11TS/S-LFA-3 in the ENU induced genetically altered cells. Histological evidences, cytotoxic study, PI-FACS cell-cycle analysis and TUNEL assay confirmed the apoptotic death of glioma cells by T11TS treatment in which p53 is mutated. From the present study we can conclude that ENU administration causes genomic instability along with mutations in p53 during the process of gliomagenesis. Whereas, T11TS/S-LFA3 demonstrated the potential to induce apoptosis of these tumor cells even when p53 is mutated and thus showed its immense potential to be an anti-neoplastic probe against p53 mutated diverse types of tumors.