Inter-alu PCR detects high frequency of genetic alterations in glioma cells exposed to sub-lethal cisplatin.
Increased genomic instability contributes to higher frequency of secondary drug resistance and neoplastic progression in tumors as well as in cells exposed to sub-lethal concentrations of chemotherapeutic agents. We have used PCR based DNA fingerprinting techniques of randomly amplified polymorphic DNA (RAPD) and inter-alu PCR to study this phenomenon in the tumor genome. The choice of the primer, either random (for RAPD) or specific (inter-alu PCR) can determine the nature of alterations being assessed. We have compared the inter-alu PCR and RAPD profiles of U87MG glioblastoma cells exposed to sequentially increasing low doses of cisplatin for 24 passages to that of untreated controls. Inter-alu PCR, with 2 primers, demonstrated a number of alterations in the treated cells, in the form of loss / gain and changes in the intensity of bands. No changes were observed by RAPD analysis with 5 primers, however, indicating a preferential increase in the alu mediated recombination frequency in the treated cells (p = 1.866 x 10(-4)). The number of changes observed with respect to the corresponding leucocyte DNA in the inter-alu PCR profile of 26 primary tumors (Grade II = 13; Grade IV = 13), resected before chemotherapy, for the 2 inter-alu primers was very small. We present a novel application of the inter-alu PCR in detecting alterations in long term cultured cells at low dose exposure to a chemotherapeutic agent. Our results suggest that alu mediated recombination may be important in cells exposed to sub-lethal doses of cisplatin but not in the genesis of primary glioma.
Srivastava
Tapasya
T
Department of Biochemistry, All India Institute of Medical Sciences, New Delhi.
Seth
Anandita
A
Datta
Kamal
K
Chosdol
Kunzang
K
Chattopadhyay
Parthaprasad
P
Sinha
Subrata
S
D020087:Alu Elements; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D005910:Glioma / Q000235:genetics* / Q000473:pathology; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*
D000970:Antineoplastic Agents; D002945:Cisplatin