title: Hsp27, Hsp70 and mismatch repair proteins hMLH1 and hMSH2 expression in peripheral blood lymphocytes from healthy subjects and cancer patients.
abstract: Mismatch repair (MMR) deficiency and higher expression levels of heat shock proteins (Hsps) have been implicated with drug resistance to topoisomerase II poisons (doxorubicin) and to platinum compounds (cisplatin). This study was designed to determine individual influences of doxorubicin and cisplatin treatment on the expression of Hsp27, Hsp70, hMLH1 and hMSH2 proteins and in the DNA damage status in peripheral blood lymphocytes (PBLs). In addition, we studied whether these proteins and the DNA damage correlated with the survival of cancer patients. PBLs from 10 healthy donors and 25 cancer patients (before and after three cycles of chemotherapy) were exposed to in vitro treatments: C (control), HS (heat shock at 42 degrees C), Do or Pt (doxorubicin or cisplatin alone), and HS+Do or HS+Pt (heat shock+doxorubicin or heat shock+cisplatin). PBLs were collected at time 0 (T0: immediately after drug treatment) and after 24h of repair (T24). Hsp27, Hsp70, hMLH1 and hMSH2 were studied by immunocytochemistry and the DNA damage by alkaline comet assay. Immunofluorescence studies and confocal microscopy revealed that hMLH1 and hMSH2 colocalized with Hsp27 and Hsp72 (inducible form of Hsp70). hMLH1 and hMSH2 were significantly induced by Pt and HS+Pt at T24 in cancer patients, but only modestly influenced by Do. Cancer patients presented higher basal expression of total and nuclear Hsp27 and Hsp70 than controls, and these proteins were also increased by HS, Do and HS+Do. The Hsp70 induction by Pt and HS+Pt was noted in cancer patients, especially nuclear Hsp70. In cancer patients, basal DNA damage was slightly higher than in healthy persons; and after Pt and HS+Pt treatments, DNA migration and number of apoptotic cells were higher than controls. Hsps accomplished a cytoprotective function in pre-chemotherapy PBLs (HS before Do or Pt), but not in post-chemotherapy samples. In Pt-treated patients the ratio N/C (nuclear/cytoplasmic) of Hsp27 was related to disease free survival and overall survival, and hMSH2 correlated with overall survival. The results point to the utility of these molecules and of the comet assay as possible predictive markers.
authors.affiliation: Oncology Laboratory, Institute of Experimental Medicine and Biology of Cuyo, Regional Center for Scientific and Technological Research, Mendoza, Argentina. snadin@lab.cricyt.edu.ar
authors.forename: Silvina Beatriz
authors.initials: SB
authors.lastname: Nadin
authors.forename: Laura M
authors.initials: LM
authors.lastname: Vargas-Roig
authors.forename: Gisela
authors.initials: G
authors.lastname: Drago
authors.forename: Jorge
authors.initials: J
authors.lastname: Ibarra
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Ciocca
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000032:analysis / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D002945:Cisplatin / Q000627:therapeutic use; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000032:analysis; D004249:DNA Damage; D053843:DNA Mismatch Repair; D004317:Doxorubicin / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D005260:Female; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007223:Infant; D008214:Lymphocytes / Q000737:chemistry / Q000378:metabolism; D008297:Male; D018832:Molecular Chaperones; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000032:analysis / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000032:analysis / Q000378:metabolism*; D009369:Neoplasms / Q000188:drug therapy* / Q000401:mortality; D009687:Nuclear Proteins / Q000032:analysis / Q000378:metabolism*; D011379:Prognosis
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D015415:Biomarkers; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; C501486:MLH1 protein, human; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D004317:Doxorubicin; D004247:DNA; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D002945:Cisplatin