Enhanced EJ Cell Killing of (125)I Radiation by Combining with Cytosine Deaminase Gene Therapy Regulated by Synthetic Radio-Responsive Promoter

Enhanced tumor inhibiting effect of 131I-BDI-1-based radioimmunotherapy and cytosine deaminase gene therapy modulated by a radio-sensitive promoter in nude mice bearing bladder cancer

Radioimmunotherapy (RIT) has great potential in cancer therapy. However, its efficacy in numerous tumors is restricted due to myelotoxicity, thereby limiting the dose of radionuclide. To increase tumor radiosensitivity, we incorporated the recombinant lentivirus into the EJ cells (bladder cancer [BC] cells), and examined the combined anti-tumor effects of RIT with 131I-BDI-1(131I-monoclonal antibody against human BC-1) and gene therapy (GT). The recombinant lentivirus was constructed and packed. The animal xenograft model was built and when the tumor reached about 0.5 cm in diameter, the mice were randomly separated into four groups: (1) RIT + GT: the xenografts were continuously incorporated with the recombinant lentivirus for two days. And 7.4 MBq 131I-BDI-1 was IV-injected, and 10 mg prodrug 5-fluorocytosine (FC) was IV-injected for 7 days, (2) RIT: same dose of 131I-BDI-1 as the previous group mice, (3) GT: same as the first group, except no 131I-BDI-1, and (4) Untreated. Compute tumor volumes in all groups. After 28 days the mice were euthanized and the tumors were extracted and weighed, and the inhibition rate was computed. The RIT + GT mice, followed by the RIT mice, exhibited markedly slower tumor growth, compared to the control mice. The tumor size was comparable between the GT and control mice. The tumor inhibition rates after 28 days of incubation were 42.85 ± 0.23%, 27.92 ± 0.21% and 0.57 ± 0.11% for the four groups, respectively. In conclusion, RIT, combined with GT, suppressed tumor development more effectively than RIT or GT alone. This data highlights the potent additive effect of radioimmune and gene therapeutic interventions against cancer.

Analysis of iodinated quorum sensing peptides by LC-UV/ESI ion trap mass spectrometry

Five different quorum sensing peptides (QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C₁₈ reversed phase HPLC system, applying a linear gradient of water and acetonitrile containing 0.1% (m/v) formic acid as mobile phase. Electrospray ionization (ESI) ion trap mass spectrometry was used for the identification of the modified peptides, while semi-quantification was performed using total ion current (TIC) spectra. Non-iodinated peptides and mono- and di-iodinated peptides (NIP, MIP and DIP respectively) were well separated and eluted in that order. Depending on the used iodination method, iodination yields varied from low (2%) to high (57%).