RESUMO
Radiotherapy effectively destroys cancer cells in many sites of the body, but several limitations remain. This study investigated alternative splicing, which is a common mechanism of increased diversity in mRNAs and proteins. The relationships of alternative splicing to DNA damage and radiation such as UV and ionizing radiation were analyzed. The DNA damage responses of many genes involved in alternative splicing were compared between non-radiation and radiation treatments. Drugs that affect radioresistence or radiosensitization by modulating the effects of alternative splicing and radiation were also reviewed.
Assuntos
Processamento Alternativo/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Preparações Farmacêuticas/administração & dosagem , Humanos , RNA Mensageiro/genética , Tolerância a Radiação/genéticaRESUMO
BACKGROUND: Focal hypermethylation in promoter regions of tumor suppressor genes against the background of global hypomethylation is a landmark of carcinogenesis. This study aimed to investigate the methylation status of retinoic acid receptor beta2 (RARß2) and long interspersed nuclear elements (LINE-1) in different stages of esophageal squamous cell carcinoma (ESCC). METHOD: The tumor and adjacent normal esophageal tissues from 125 male ESCC patients who underwent primary surgery were analyzed for the methylation status of RARß2 promoter and LINE-1 through methylation-specific polymerase chain reaction and pyrosequencing. RESULTS: RARß2 hypermethylation was detected in 20% of the tumor samples, but not in the normal counterparts. The methylation frequency of LINE-1 was significantly lower in the tumor than in the normal parts (median: 67.7% vs. 80%, P < 0.0005). Ninety-eight patients (78.4%) had both RARß2 hypermethylation and LINE-1 hypomethylation or either one. There was a trend toward higher risk of advanced T stage (P for trend = 0.05) or lymph node metastasis (P for trend = 0.02) when more adverse gene methylation profiles were present. CONCLUSION: Methylation status of RARß2 and LINE-1 was related to the development and possibly the severity of ESCC.