title: Molecular aspects on adriamycin interaction with hmga1 regulatory region and its inhibitory effect on HMGA1 expression in human cervical cancer.
abstract: High mobility group A1 (HMGA1), a non-histone chromosomal protein, is highly expressed in a wide range of human cancers including cervical, breast, and prostate cancers. Therefore, hmga1 gene is considered as an attractive potential target for anticancer drugs. We have chosen 27 bp DNA sequence from a regulatory region of hmga1 promoter and studied its interaction with adriamycin (ADM) and in vitro expression of HMGA1 in the presence of ADM in HeLa cell line. A variety of biophysical techniques were employed to understand the characteristics of [DNA-ADM] complex. Spectrophotometric titration data, DNA denaturation profiles, and quenching of fluorescence of ADM in the presence of DNA demonstrated a strong complexation between DNA and ADM with a high binding affinity (Ka) of 1.3 × 10(6) M(-1) and a stoichiometry of 1:3 (drug:nucleotide). The energetics of binding obtained from isothermal titration calorimetry and differential scanning calorimetry suggest the binding to be exothermic and enthalpy (∆H, -6.7 ± 2.4 kcal M(-1)) and entropy (TΔS, 18.5 ± 6.4 kcal M(-1)) driven (20°C), which is typical of intercalative mode of binding. Further, results on decreased expression (by ~70%) of HMGA1 both at mRNA and protein levels in association with the observed cell death (by ~75%) in HeLa cell line, clearly confirm that ADM does target hmga1; however, the effect of ADM on genes other than hmga1 either directly or via hmga1-mediated pathways cannot be ruled out in the observed cytotoxicity. Therefore, hmga1 in general and particularly the regulatory region is a promising target for therapeutic strategy in combating cancer.
authors.affiliation: a Department of Biochemistry , All India Institute of Medical Sciences , New Delhi 110029 , India.
authors.forename: Md Zahid
authors.initials: MZ
authors.lastname: Akhter
authors.affiliation: a Department of Biochemistry , All India Institute of Medical Sciences , New Delhi 110029 , India.
authors.forename: Kalpana
authors.initials: K
authors.lastname: Luthra
authors.affiliation: a Department of Biochemistry , All India Institute of Medical Sciences , New Delhi 110029 , India.
authors.forename: Moganty R
authors.initials: MR
authors.lastname: Rajeswari
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000737:chemistry* / Q000494:pharmacology; D002152:Calorimetry, Differential Scanning; D016923:Cell Death / Q000235:genetics; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004317:Doxorubicin / Q000737:chemistry* / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D024003:HMGA Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D006801:Humans; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D044366:Transition Temperature; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism
chemical_list: D000903:Antibiotics, Antineoplastic; D024003:HMGA Proteins; D004317:Doxorubicin; D004247:DNA
keywords: DNA–drug interaction; adriamycin; hmga1 expression; spectroscopy; thermodynamics