PLoS ONE (Jan 2014)

Mutation induced conformational changes in genomic DNA from cancerous K562 cells influence drug-DNA binding modes.

  • Debjani Ghosh,
  • Subrata Kumar Dey,
  • Chabita Saha

DOI
https://doi.org/10.1371/journal.pone.0084880
Journal volume & issue
Vol. 9, no. 1
p. e84880

Abstract

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Normal human genomic DNA (N-DNA) and mutated DNA (M-DNA) from K562 leukemic cells show different thermodynamic properties and binding affinities on interaction with anticancer drugs; adriamycin (ADR) and daunomycin (DNM). Isothermal calorimetric thermograms representing titration of ADR/DNM with N-DNA and M-DNA on analysis best fitted with sequential model of four and three events respectively. From Raman spectroscopy it has been identified that M-DNA is partially transformed to A form owing to mutations and N-DNA on binding of drugs too undergoes transition to A form of DNA. A correlation of thermodynamic contribution and structural data reveal the presence of different binding events in drug and DNA interactions. These events are assumed to be representative of minor groove complexation, reorientation of the drug in the complex, DNA deformation to accommodate the drugs and finally intercalation. Dynamic light scattering and zeta potential data also support differences in structure and mode of binding of N and M DNA. This study highlights that mutations can manifest structural changes in DNA, which may influence the binding efficacy of the drugs. New generation of drugs can be designed which recognize the difference in DNA structure in the cancerous cells instead of their biochemical manifestation.