A novel bioluminescent tumor model of human renal cancer cell lines: an in vitro and in vivo characterization.

PURPOSE: Bioluminescent imaging permits sensitive in vivo detection and quantification of cells engineered to emit light. We developed a bioluminescent human renal cancer cell line for in vitro and in vivo studies. MATERIAL AND METHODS: The 2 human renal cell carcinoma cell lines SN12-C and SN12-L1 were stably transfected to constitutively express luciferase using a retroviral shuttle. The bioluminescent signal was correlated with tumor cell numbers in vitro. Parental and transfected cells were compared by growth kinetics and histology. Tumor burden after heterotopic injection in immune deficient mice was monitored up to 39 days. The kinetics of the bioluminescent signal was evaluated for 1 to 60 minutes following luciferin injection. RESULTS: Bioengineered renal cancer cell lines stably expressed luciferase. The growth kinetics of the cells in vitro and the histology of tumors resulting from implantation of these cells were unaffected by retroviral transfection with the luciferase gene. As few as 1,000 cells could be reliably detected. The intensity of the bioluminescent signal correlated with the number of tumor cells in vitro. Photon emission in vivo and ex vivo correlated significantly with tumor weight at sacrifice. After intraperitoneal injection of luciferin there was a time dependent change in the intensity of the bioluminescent signal with maximum photon emission at 20 minutes (optimal 17 to 25). CONCLUSIONS: Luciferase transfected human renal cancer lines allow reliable, rapid, noninvasive and longitudinal monitoring of tumor growth in vivo. The ability to assess tumor development in vivo with time is economical and effective compared to end point data experiments.

N,N-diacetyl-L-cystine improves endothelial function in atherosclerotic Watanabe heritable hyperlipidaemic rabbits.

N,N-diacetyl-L-cystine (DiNAC), a novel immunomodulator, stimulates contact sensitivity/delayed type hypersensitivity reactions in mice induced by oxazolone and reduces atherosclerosis in Watanabe heritable hyperlipidaemic (WHHL) rabbits. Forty-week-old WHHL rabbits were given DiNAC (3 micromol/kg per day) for 8 weeks, and endothelium-mediated dilatation was investigated in vivo using pulse wave analysis. A significant improvement in endothelial function was found after 3 weeks of treatment, which was further improved after 8 weeks. For experiments on isolated blood vessels, 40-week-old rabbits were treated for 3 weeks. Treatment did not affect plasma lipid levels. At termination, aortic rings from the thoracic and abdominal aorta were contracted with phenylephrine in vitro. Concentration-effect curves to acetylcholine and the calcium ionophore A 23187 were used to measure endothelium-mediated vasodilatation, and nitroprusside to elicit endothelium-independent relaxations. Abdominal aorta relaxations were generally larger than in thoracic aorta. DiNAC improved endothelium-dependent relaxations in the abdominal but not in the thoracic aorta. This effect was independent of the degree of atherosclerosis. It is concluded that DiNAC improved endothelial function in atherosclerotic rabbit arteries in vivo and in vitro, and may represent a new treatment modality for atherosclerosis-related diseases.