Rapamycin enhanced Ad-mediated transgene expression in pre-immunized mice.

<p>(A) The timeline for the pre-immunity models. Animals were primed with an intraperitoneal dose of 1×10⁸ PFU empty Ad and, 3 weeks later, subcutaneous tumors were inoculated. RM9 tumors became palpable 4-5 days post implantation; MycCaP tumors became palpable 5-7 days post implantation. At this point, rapamycin or control treatment initiated and intratumoral Ad imaging vectors were administered 4 days later. Daily rapamycin treatment was continued till the end of the study. FL bioluminescent imaging was conducted at time points indicated in B and C. (B) FL bioluminescent imaging of RM-9 bearing C57BL/6 mice on day 4 and 7. High: 5 mg/kg/day rapamycin; Medium: 1.5 mg/kg/day; Low: 0.5 mg/kg/day. n=3. (C) FL bioluminescent imaging of MycCaP bearing FVB mice (n=3 or 4) at indicated time points. (D) Quantification of imaging signal from C. Color bar of bioluminescent imaging: photon count. Error bars: mean ± SEM (n=4 for Ad only; n=3 for Ad + RAPA). * P<0.05, ** P<0.01 by two-tailed <i>t</i> test.