Increased c-Ki-ras expression in hamster lung exposed to N-nitrosodiethylamine and hyperoxia as detected by the polymerase chain reaction. |
| |
Authors: | H Ning V I Oreffo P H Gumerlock H Witschi |
| |
Institution: | Toxic Substances Research and Teaching Program, University of California, Davis 95616. |
| |
Abstract: | Neuroendocrine lung cancers can be induced in hamsters within 8-12 weeks by combined exposure to N-nitrosodiethylamine (DEN) and hyperoxia. The expression of the c-Ki-ras gene in this lung cancer model was studied using polymerase chain reaction analysis of mRNA (RNA/PCR). We used four different groups of hamsters, exposed for 6 weeks to DEN with hyperoxia (60% oxygen), DEN, hyperoxia, or ambient air, respectively. Total RNA was isolated from lung tissues and cDNA made prior to PCR amplification. A 234-bp product was amplified from c-Ki-ras cDNA and quantitated using scanning laser densitometry. The data obtained were normalized to the expression of the house keeping gene B-actin. The c-Ki-ras products were present after amplification of all hamster lung RNA samples. The hamster lungs exposed to DEN with hyperoxia displayed higher c-Ki-ras protooncogene expression than hamsters exposed to DEN, hyperoxia, or ambient air alone. Since the animals studied were sacrificed at 6 weeks, prior to the appearance of tumors, we conclude that this increased expression may indicate a role for c-Ki-ras in the initial steps in malignant transformation of neuroendocrine cells. |
| |
Keywords: | |
|
|