RESUMO
Carbonic anhydrase-related protein VIII (CA-RP VIII) is expressed in most non-small cell lung cancer, and especially strongly at the front of tumor progression. Screening analysis of CA-RP VIII expression in a panel of cultured lung cancer cell lines showed that a well differentiated adenocarcinoma cell line, PC-9, appeared to lack CA-RP VIII. Subsequently, CA8 cDNA was transfected with an expression vector into PC-9. Ectopic overexpression of CA-RP VIII reduced the growth of PC-9 cells on uncoated culture dishes, especially when the cultures were started at low cell density, but increased cell growth on laminin-coated dishes. Interestingly, ectopic CA-RP VIII expression markedly reduced caspase-3 activity induced by serum starvation and anti-cancer agents in PC-9 cells. The present findings suggest that CA-RP VIII expression promotes progression of lung cancer by multifarious mechanisms.
Assuntos
Adenocarcinoma/metabolismo , Anidrases Carbônicas/biossíntese , Carcinoma de Células Pequenas/metabolismo , Carcinoma de Células Escamosas/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas do Tecido Nervoso/biossíntese , Antineoplásicos/farmacologia , Biomarcadores Tumorais , Caspases/efeitos dos fármacos , Divisão Celular/fisiologia , Linhagem Celular Tumoral , Progressão da Doença , HumanosRESUMO
Carbonic anhydrase-related protein (CA-RP VIII) lacks a Zn-binding motif which is essential for carbonic anhydrase activity. Therefore, CA-RP VIII is believed to have a no catalytic activity and a new biological property. In the present study, CA-RP VIII expression in non-tumorous lung and non-small cell lung carcinomas was investigated. Little or no expression of CA-RP VIII was observed in human lungs by Northern-blot analysis. Reverse-transcription polymerase chain reaction analysis demonstrated CA-RP VIII mRNA in developing human lungs and, to a lesser extent, in normal lungs. Subsequent immunohistochemical staining revealed that CA-RP VIII was expressed in the pulmonary epithelium in developing lungs; however, CA-RP VIII expression was restricted in bronchial ciliated cells in adult lungs. Neither bronchial gland nor squamous metaplasia of interstitial pneumonia expressed CA-RP VIII. In contrast, CA-RP VIII was strongly expressed in almost all archival lung cancer specimens, which included 24 squamous cell carcinomas, 25 adenocarcinomas, and 6 adenosquamous cell carcinomas. Cancer cells at the front of tumor progression expressed CA-RP VIII in particular abundance. The present findings suggest that CA-RP VIII may play a role in non-small lung cell carcinomas.
