An in vivo XXXX reporter gene ( @entity1 secreted alkaline phosphatase) model to monitor @entity43 growth and response to therapeutics.

@entity1 @entity43 @entity5 @entity19 @entity3003 @entity900 @entity70727 @entity204 @entity902
PURPOSE: Developing new anticancer therapeutic regimens requires the measurement of @entity5 cell growth in response to treatment. This is often accomplished by injecting immunocompromised @entity19 with cells from @entity5 tissue or cell lines. After treating the animals, @entity5 weight or volume is measured. Such methods are complicated by inaccuracies in measuring @entity5 mass and often animals must be killed to measure @entity5 burden. An in vivo @entity5 model system is presented in which the @entity5 cell line was stably transfected with a constitutively expressed marker gene: secreted @entity1 placental alkaline phosphatase protein (SEAP). The SEAP gene codes for a heat-stable protein that is produced at levels proportional to the amount of @entity5 cells in the animal. The SEAP protein is detectable in small blood samples so that animals can be repeatedly sampled over the trial period to monitor the course of @entity5 progression. METHODS: @entity70727 @entity43 cells were stably transfected with pCMV-SEAP. The @entity70727 -SEAP cells were maintained in vitro to monitor the relationship between cell number and SEAP production. Experiments were performed in vivo to determine whether SEAP levels in blood corresponded to @entity5 burden. @entity70727 -SEAP cells were injected s.c. or intraperitoneally into @entity19 and @entity5 volume was measured as well as plasma SEAP levels as the @entity5 developed. RESULTS: S.c. @entity5 volume correlated well with plasma SEAP levels ( R(2)=0.95). @entity70727 -SEAP cells were also injected intraperitoneally into @entity19 and grown as @entity5 . After 3 weeks the animals were killed and the @entity5 were dissected and weighed. SEAP levels in plasma samples from the time of @entity204 correlated with @entity5 weight ( R(2)=0.87). Experiments were performed to determine whether measuring SEAP levels could be used to monitor @entity43 cell response to @entity902 -containing chemotherapeutic drugs. @entity70727 -SEAP cells cultured in vitro were treated with the @entity902 -containing drug @entity3003 . @entity3003 treatment decreased both cell proliferation and SEAP levels in culture medium. The constitutive rate of SEAP secretion per cell (nanograms SEAP per microgram DNA) was found not to be altered by @entity3003 treatment. Therefore changes in SEAP level reflect changes in @entity70727 @entity5 cell number, and not changes in regulation of SEAP secretion due to @entity902 containing chemotherapeutic drug treatment. @entity70727 cells were injected intraperitoneally into @entity19 and the @entity19 were treated with the @entity902 -containing drugs @entity900 or @entity3003 . Measurements of plasma SEAP over the treatment period showed @entity70727 -SEAP @entity43 growth to be inhibited by @entity900 and @entity3003 treatment. CONCLUSION: The SEAP marker protein is constitutively expressed by @entity5 cells and blood levels are correlated with @entity5 cell number and burden. The results of these studies indicate that SEAP may be used as an in vivo reporter gene in a @entity19 model to monitor @entity5 growth and response to therapeutics. Future studies will utilize this model to investigate novel chemotherapeutic approaches to treating @entity43 .
