Search

Objective: To study the in vitro accumulation of (18)F-FHBG, its in vivo distribution and (18)F-FHBG PET-CT imaging for reporter gene (HSV1-tk) in nude mice with a xenograft of breast adenocarcinoma., Methods: The in vitro uptake of (18)F-FHBG in tumor cells of T47D and T47D-tk and the distribution of (18)F-FHBG in normal Kunming mice and nude mice with breast adenocarcinoma xenograft were detected by well-type gamma counter. Reporter gene PET-CT imaging with (18)F-FHBG was performed in nude mice with a xenograft of breast adenocarcinoma. And the expression location of HSV1-tk gene could be monitored by observing the in vitro and in vivo accumulation of (18)F-FHBG., Results: The in vitro uptake of (18)F-FHBG in T47D-tk cells (143.67 dpm/10(4) +/- 5.82 dpm/10(4) cells) was significantly higher than that in T47D cells (2.23 dpm/10(4) +/- 0.23 dpm/10(4) cells) at 60 and 120 min post-injection (P < 0.001) and reaches a plateau at 60 min. In normal Kunming mice, (18)F-FHBG was mainly distributed in liver, intestine, kidney and bladder while there was no obvious radioactive accumulation in brain. (18)F-FHBG accumulated at a significantly higher level in T47D-tk tumors than in T47D tumors and its accumulation yielded the best image effect at 2 h by PET-CT imaging in nude mice., Conclusion: The in vitro uptake of (18)F-FHBG in T47D-tk cells is significantly higher than that in T47D cells. (18)F-FHBG is mainly excreted by digestive tract and urinary tract in mice. It agrees with the expression pattern of HSV1-tk gene. (18)F-FHBG can determine the localization of HSV1-tk gene expression in an efficient way. This study will offer a monitoring method and scientific base for (18)F-FHBG reporter gene imaging and HSV1-tk gene therapy in tumors.

Objective: To further identify the breast adenocarcinoma cell line T47D-tk stably expressing the suicide gene HSV1-tk, observe its growing characteristics, and establish an animal model of implanted breast adenocarcinoma., Methods: Retroviral vector of HSV1-tk gene and breast carcinoma cell line T47D-tk stably expressing the HSV1-tk gene were established. Breast carcinoma cells of the lines T47D and T47D-tk were cultured, and observed by inverted microscope. Growth curve was drawn. Genomic DNA of T47D-tk cells was extracted, and amplified by PCR with HSV1-tk and HSV1-tk P2 as primers. Agarose gel electrophoresis was used to identify the HSV1tk gene. Suspensions of T47D and T47D-tk cells were inoculated subcutaneously at bilateral roots of foreleg of female BALB/c nude mice respectively. The growth of tumor was observed every day., Results: PCR showed 1131 bp fragment in the T47D-tk genome, but not in the T47D genome. The numbers of growing T47D cells on days 3, and 7 were (10.00 +/- 1.30) x 10(3) and (19.25 +/- 0.66) x 10(3) respectively, not significantly different from those of the T47D-tk cells [(10.25 +/- 0.90) x 10(3) and (19.00 +/- 1.80) x 10(3) respectively, both P > 0.05]. The time needed for tumor formation after the inoculation of T47D cells was (9.67 +/- 0.33) d, not significantly different from that of the T47D-tk cells [(9.83 +/- 0.48) d, P > 0.05]. The tumor size 19 days after inoculation of the T47D cells was (72.17 +/- 25.88) mm(3), not significantly different from that of the T47D-tk cells [(70.66 +/- 22.16) mm(3), P > 0.05]., Conclusion: The T47D-tk cells have integrated the HSV1-tk gene without changing its growing characteristics. An animal model of implanted breast cancer has been successfully established. The T47D and T47D-tk subcutaneous xenografts offer the foundation for further study of gene imaging and gene therapy.