| Summary: | 博士 === 國立陽明大學 === 生物醫學影像暨放射科學系 === 101 === Here a human hepatocellular carcinoma Huh7/NF-kB-tk-luc2/rfp cell clone was established using NF-kB responsive element as a promoter to drive herpes simplex virus thymidine kinase (tk) and firefly luciferase (luc2) dual reporter genes for monitoring NF-kB activity, and co-transfected with red fluorescent protein gene (rfp) for identifying the viable tumor cells. With this Huh7/NF-kB-tk-luc2/rfp tumor-bearing animal model combined with multimodalities of molecular imaging, simultaneous imaging of temporal changes of NF-kB activity and viable tumor cells during sorafenib treatments could be performed. Sorafenib is a multikinase inhibitor approved by FDA for the treatment of renal carcinoma via Ras-Raf-MAPK-MEK-ERK pathway, and was found to be beneficial for other types of cancers as well, especially hepatoma. NF-kB responsive element with tk-luc2 dual reporter genes were used to combined with multimodalities of molecular imaging, such as bioluminescent imaging (BLI) for tracking the real-time NF-kB activity, and rfp gene for the imaging (RFPI) assay of viable tumor cells during sorafenib treatment. The NF-kB activity has been reported to be associated with chemo- and radioresistance during cancer treatments. The results showed that sorafenib could suppress the NF-κB/DNA binding activity, and the expression of downstream effector proteins to enhance tumor cell killing through inhibition of anti-apoptotic pathway, tumor cell proliferation, and invasion, while increase apoptosis of tumor cells. In addition, the relative photon fluxes obtained from RFPI and BLI, each represented the viable tumor cells and cells with NF-κB activation, respectively, decreased after sorafenib treatment by 50 to 65%, and 87.5 to >90%, suggesting that the percentage of suppression of NF-κB activation was much higher than that of HCC tumor cell killing in the tumor mass at anytime during sorafenib treatments. In conclusion, simultaneous molecular imaging of the temporal change of NF-κB activity and the viable tumor cells in the same Huh7/NF-κB-tk-luc2/rfp tumors of the animal may reflect the real status of NF-κB activity and the viable tumor cells at the time of imaging. This system may be applied for screening the potential chemotherapeutic drugs, and for the therapeutic efficacy evaluation of new preclinical trials, which using NF-κB as a major target.
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