Application Of Specific Nucleic Acid-triggered Curcumin Prodrug Activation System In The Treatment Of Bladder

Part 1Preparation of curcumin prodrugs and their anti-tumor activities in vitroObjectives To prepare the prodrugs of curcumin, which could be selectively activated in tumor cells, in order to establish a basis for further development of targeted chemotherapy for cancer. Methods Based on the molecular structure of curcumin, the N-maleoyl-L-valine-curcumin (NVC), N-maleoyl-glycine-curcumin (NGC) were chemically synthesized and identified by IR spectroscopy. After treatment with these two prodrugs for 6～24h, the growth inhibition rates on human bladder cancer EJ cells and renal tubular epithelial (HKC) cells were detected by MTT colorimetry. Results After treatment with 20μmol/L～40μmol/L MVC and MGC for 6～24h, the growth inhibitory effects on EJ cells were 6.71%～65.13%% (P<0.05), 10.96%～73.01% (P<0.05), respectively, with dose- and time-dependent characters. When compared with the curcumin of same concentrations, the growth inhibitory effects of these two prodrugs on HKC cells were significantly decreased (P<0.01). Conclusion The two-curcumin prodrugs: N-maleoyl-L-valine-curcumin (NVC), N-maleoyl-glycine- curcumin (NGC) were chemically synthesized successfully and were identified that they both could inhibit the growth of tumor cell in vitro. Furthermore, the two prodrugs of curcumin were found less toxic in HKC cell than curcumin.Part 2Apoptosis of bladder cancer cells induced by curcumin prodrugs in vitroObjectives: To study the growth inhibition effects of N-maleoyl-L-valine-curcumin (NVC), N-maleoyl-glycine- curcumin (NGC) on human bladder cancer cell line EJ, renal tubular epithelial (HKC) cells, and the mechanisms for further developing researches on their anti-tumor activity and apoptosis effects. Methods After treatment with these two prodrugs prepared before for 6～24h, the growth inhibition rates on human bladder cancer EJ cells and renal tubular epithelial (HKC) cells were detected by MTT colorimetry, cell count by Typan blue. Cell cycle phases were inspected by flow cytometery (FCM). The apoptosis was detected by TUNEL and DNA ladder methods. The morphological changes of cancer cells were observed under electronic microscopy. Results After treatment with 20μmol/L～40μmol/L NVC and NGC for 6～24h, the growth inhibitory effects on EJ cells were 6.71%～65.13% (P<0.05), 10.96%～73.01% (P<0.05), respectively, with dose- and time-dependent manners. FCM, DNA ladder and TUNEL methods exhibited that apoptosis occurred in some cancer cell with trapeziform bands on electrophoresis. Conclusion Activation of curcumin prodrugs via hydrolysis functions of cellular esterase, could inhibit the growth activities of tumor cells, and reduce the side effects on normal diploid cells through blocking cellular proliferation and inducing apoptosis.Part 3The preparation of curcumin nanoparticles and their characterizationObjectives: To prepare the nanoparticles of curcumin and study their characteristic, in order to establish a basis for further development of targeted chemotherapy of nanotechnology for cancer. Methods With a modified spontaneous emulsification solvent diffusion method to make various types of PLGA and PLA polymers for preparation of nanoparticles of curcumin, through acetone/ethanol and PC/ethanol respectively and calculate the drug loading and drug trapping efficiency of curcumin Results: The drug loading of curcumin nanoparticles should be 3.15% and the drug trapping efficiency of curcumin nanoparticles should be 18.9%. Conclusion After been packed, the curcumin nanoparticles can be seen dissipated in the water and formed a stable suspensive emulsion; These phenomenons shows that the diffluent characteristic of curcumin has been changed through packed, which afford a new way to the chemotherapy therapy of cancer. Part 4Synthesis of specific nucleic acid-triggered prodrugs of curcumin and primary characterization of the prodrugsObjectives On the basis of our former study, We have linked the prodrugs of curcumin and catalyst imidazole with antisense oligodeoxynucleotide of survivin. Methods: With the usage of chemical synthesis; high performance liquid chromatography and controlled pore glass, the prodrugs of curcumin and catalyst imidazole were linked with the antisense oligodeoxynucleotide of survivin. The new material was identified by the high performance liquid chromatography. Results: The identification of the high performance liquid chromatography showed that the prodrugs of curcumin and catalyst imidazole were linked with the antisense oligodeoxynucleotide of survivin successfully. Conclusion: The specific nucleic acid-triggered curcumin prodrug activation system is an efficient targeted therapy of tumor.Part 5Specific nucleic acid-triggered prodrugs of curcumin in vivoObjectives To investigate the antitumor activity and side effect of the specific nucleic acid-triggered curcumin prodrug activation system in vivo. Methods: With the subcutaneous tumor model of nude mouse; drug injection inside tumor and histological section; the side effect and the tumor growth inhibition were detected. Results: The specific nucleic acid-triggered curcumin prodrug activation system is an efficient targeted therapy of tumor and has a less cytotoxin than curcumin. Conclusion: The specific nucleic acid-triggered curcumin prodrug activation system is an efficient targeted therapy of tumor, which established a basis for further development of targeted chemotherapy for cancer.