BACKGROUND: The generation of DNA interstrand cross-links is thought to be important in the cytotoxicity of nitrogen mustard alkylating agents, such as melphalan, which have antitumor activity. Cell lines with mutations in recombinational repair pathways are hypersensitive to nitrogen mustards. Thus, resistance to melphalan may require accelerated DNA repair by either recombinational repair mechanisms involving Rad51-related proteins (including x-ray repair cross-complementing proteins Xrcc2, Xrcc3, and Rad52) or by nonhomologous endjoining involving DNA-dependent protein kinase (DNA-PK) and Ku proteins. We investigated the role of DNA repair in melphalan resistance in epithelial tumor cell lines. METHODS: Melphalan cytotoxicity was determined in 14 epithelial tumor cell lines by use of the sulforhodamine assay. Homologous recombinational repair involving Rad51-related proteins was investigated by determining the levels of Rad51, Rad52, and Xrcc3 proteins and the density of nuclear melphalan-induced Rad51 foci, which represent sites of homologous recombinational repair. Nonhomologous endjoining was investigated by determining the levels of Ku70 and Ku86 proteins and DNA-PK activity. Linear regression analysis was used to analyze correlations between the various protein levels, DNA-PK activity, or Rad51 foci formation and melphalan cytotoxicity. All statistical tests were two-sided. RESULTS: Melphalan resistance was correlated with Xrcc3 levels (r =.587; P =.027) and the density of melphalan-induced Rad51 foci (r =.848; P =.008). We found no correlation between melphalan resistance and Rad51, Rad52, or Ku protein levels or DNA-PK activity. CONCLUSION: Correlations of melphalan resistance in epithelial tumor cell lines with Xrcc3 protein levels and melphalan-induced Rad51 foci density suggest that homologous recombinational repair is involved in resistance to this nitrogen mustard.
BACKGROUND: The generation of DNA interstrand cross-links is thought to be important in the cytotoxicity of nitrogen mustard alkylating agents, such as melphalan, which have antitumor activity. Cell lines with mutations in recombinational repair pathways are hypersensitive to nitrogen mustards. Thus, resistance to melphalan may require accelerated DNA repair by either recombinational repair mechanisms involving Rad51-related proteins (including x-ray repair cross-complementing proteins Xrcc2, Xrcc3, and Rad52) or by nonhomologous endjoining involving DNA-dependent protein kinase (DNA-PK) and Ku proteins. We investigated the role of DNA repair in melphalan resistance in epithelial tumor cell lines. METHODS:Melphalancytotoxicity was determined in 14 epithelial tumor cell lines by use of the sulforhodamine assay. Homologous recombinational repair involving Rad51-related proteins was investigated by determining the levels of Rad51, Rad52, and Xrcc3 proteins and the density of nuclear melphalan-induced Rad51 foci, which represent sites of homologous recombinational repair. Nonhomologous endjoining was investigated by determining the levels of Ku70 and Ku86 proteins and DNA-PK activity. Linear regression analysis was used to analyze correlations between the various protein levels, DNA-PK activity, or Rad51 foci formation and melphalancytotoxicity. All statistical tests were two-sided. RESULTS:Melphalan resistance was correlated with Xrcc3 levels (r =.587; P =.027) and the density of melphalan-induced Rad51 foci (r =.848; P =.008). We found no correlation between melphalan resistance and Rad51, Rad52, or Ku protein levels or DNA-PK activity. CONCLUSION: Correlations of melphalan resistance in epithelial tumor cell lines with Xrcc3 protein levels and melphalan-induced Rad51 foci density suggest that homologous recombinational repair is involved in resistance to this nitrogen mustard.
Authors: David Abasiwani Alagpulinsa; Shmuel Yaccoby; Srinivas Ayyadevara; Robert Joseph Shmookler Reis Journal: Cancer Biol Ther Date: 2015-05-21 Impact factor: 4.742
Authors: Arghya Ray; Durgadevi Ravillah; Deepika S Das; Yan Song; Eva Nordström; Joachim Gullbo; Paul G Richardson; Dharminder Chauhan; Kenneth C Anderson Journal: Br J Haematol Date: 2016-04-20 Impact factor: 6.998
Authors: Wei-Yu Lin; Nicola J Camp; Lisa A Cannon-Albright; Kristina Allen-Brady; Sabapathy Balasubramanian; Malcolm W R Reed; John L Hopper; Carmel Apicella; Graham G Giles; Melissa C Southey; Roger L Milne; Jose I Arias-Pérez; Primitiva Menéndez-Rodríguez; Javier Benítez; Magdalena Grundmann; Natalia Dubrowinskaja; Tjoung-Won Park-Simon; Thilo Dörk; Montserrat Garcia-Closas; Jonine Figueroa; Mark Sherman; Jolanta Lissowska; Douglas F Easton; Alison M Dunning; Preetha Rajaraman; Alice J Sigurdson; Michele M Doody; Martha S Linet; Paul D Pharoah; Marjanka K Schmidt; Angela Cox Journal: J Med Genet Date: 2011-05-31 Impact factor: 6.318
Authors: Veronica L Martinez-Marignac; Amélie Rodrigue; David Davidson; Martin Couillard; Ala-Eddin Al-Moustafa; Mark Abramovitz; William D Foulkes; Jean-Yves Masson; Raquel Aloyz Journal: PLoS One Date: 2011-01-24 Impact factor: 3.240