The role of RAD51 in etoposide (VP16) resistance in small cell lung cancer
| Autor: | Cecilia Lundin, Mogens Spang-Thomsen, Thomas Helleday, Lone Petersen, Lasse Tengbjerg Hansen |
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| Rok vydání: | 2003 |
| Předmět: |
Cancer Research
Lung Neoplasms DNA Repair DNA repair viruses genetic processes RAD51 DNA-Activated Protein Kinase Biology Protein Serine-Threonine Kinases Downregulation and upregulation medicine Tumor Cells Cultured Humans Nuclear protein Carcinoma Small Cell Etoposide Topoisomerase Nuclear Proteins Transfection DNA-Binding Proteins enzymes and coenzymes (carbohydrates) Oncology Cell culture Drug Resistance Neoplasm health occupations Cancer research biology.protein Rad51 Recombinase biological phenomena cell phenomena and immunity medicine.drug |
| Zdroj: | International journal of cancer. 105(4) |
| ISSN: | 0020-7136 |
| Popis: | Etoposide (VP16) is a potent inducer of DNA double-strand breaks (DSBs) and is efficiently used in small cell lung cancer (SCLC) therapy. However, acquired VP16 resistance remains an important barrier to effective treatment. To understand the underlying mechanisms for VP16 resistance in SCLC, we investigated DSB repair and cellular VP16 sensitivity of SCLC cells. VP16 sensitivity and RAD51, DNA-PK(cs), topoisomerase IIalpha and P-glycoprotein protein levels were determined in 17 SCLC cell lines. In order to unravel the role of RAD51 in VP16 resistance, we cloned the human RAD51 gene, transfected SCLC cells with RAD51 sense or antisense constructs and measured the VP16 resistance. Finally, we measured VP16-induced DSBs in the 17 SCLC cell lines. Two cell lines exhibited a multidrug-resistant phenotype. In the other SCLC cell lines, the cellular VP16 resistance was positively correlated with the RAD51 protein level. In addition, downregulation or overexpression of the RAD51 gene altered the VP16 sensitivity. Furthermore, the levels of the RAD51 and DNA-PK(cs) proteins were related to VP16-induced DSBs. The results suggest that repair of VP16-induced DSBs is mediated through both RAD51-dependent homologous recombination and DNA-PK(cs)-dependent nonhomologous end-joining and may be a determinant of the variation in clinical treatment effect observed in human SCLC tumors of identical histologic subtype. Finally, we propose RAD51 as a potential target to improve VP16 efficacy and predict tumor resistance in the treatment of SCLC patients. |
| Databáze: | OpenAIRE |
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