Gene-directed enzyme/prodrug therapy (GDEPT) mediated by mesenchymal stromal cells (MSC) was already approved for clinical study on a progressive disease refractory to standard therapy. In this work, we examined the effect of several GDEPT approaches on chemoresistant cells. First, we derived 5-fluorouracil (5-FU)-resistant variant of human colorectal adenocarcinoma cells HT-29 designated HT-29/EGFP/FUR. Our data show that the upregulation of thymidylate synthase (TS) and downregulation of thymidine phosphorylase (TP), orotate phosphoribosyl transferase (OPRT) and dihydropyrimidine dehydrogenase (DPD) contributed to the 5-FU resistance in cancer cells. Next, we combined the MSC expressing either yeast cytosine deaminase (CD-MSC) or fusion yeast CD::uracil phosphoribosyl transferase (CD::UPRT-MSC) and prodrug 5-fluorocytosine (5-FC) in a cell-mediated GDEPT approach. Bystander cytotoxic effect in the direct co-cultures of the tumor and therapeutic cells mixed in a 5:1 ratio resulted in 55% and 70% inhibition of proliferation, respectively. However, the acquired chemoresistance to 5-FU can be overcome by introducing the prodrug-converting transgene into the tumor cells. When the transgene CD::UPRT was expressed in the chemoresistant cells (CD::UPRT-FUR), substantial suicide effect and a 90% decrease in viability was observed using non-toxic concentration of 62.5 µg/ml 5-FC. In summary, we demonstrate here that the transgene introduction circumvented 5-FU resistance in the tumor cells.

• MeSH
• fluorouracil farmakologie   terapeutické užití   MeSH
• genetická terapie metody   MeSH
• lidé MeSH
• myši SCID MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• prekurzory léčiv farmakologie   terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We constructed recombinant vaccinia viruses (VACVs) coexpressing the insulin-like growth factor-binding protein-3 (IGFBP-3) gene and the fusion gene encoding the SigE7Lamp antigen. The expression of the IGFBP-3 transgene was regulated either by the early H5 promoter or by the synthetic early/late (E/L) promoter. We have shown that IGFBP-3 expression regulated by the H5 promoter yielded higher amount of IGFBP-3 protein when compared with the E/L promoter. The immunization with P13-SigE7Lamp-H5-IGFBP-3 virus was more effective in inhibiting the growth of TC-1 tumors in mice and elicited higher T-cell response against VACV-encoded antigen than the P13-SigE7Lamp-TK(-) control virus. We found that high-level production of IGFBP-3 enhanced virus replication both in vitro and in vivo, resulting in more profound antigen stimulation. Production of IGFBP-3 was associated with a higher adsorption rate of P13-SigE7Lamp-H5-IGFBP-3 to CV-1 cells when compared with P13-SigE7Lamp-TK(-). Intracellular mature virions (IMVs) of the IGFBP-3-expressing virus P13-SigE7Lamp-H5-IGFBP-3 have two structural differences: they incorporate the IGFBP-3 protein and they have elevated phosphatidylserine (PS) exposure on outer membrane that could result in increased uptake of IMVs by macropinocytosis. The IMV PS content was measured by flow cytometry using microbeads covered with immobilized purified VACV virions.

• MeSH
• antigeny virové imunologie   MeSH
• IGFBP-3 genetika   imunologie   MeSH
• imunizace metody   MeSH
• lidský papilomavirus 16 genetika   imunologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• Papillomavirus E7 - proteiny genetika   imunologie   MeSH
• promotorové oblasti (genetika) MeSH
• replikace viru imunologie   MeSH
• T-lymfocyty imunologie   MeSH
• tvorba protilátek MeSH
• vakcinace metody   MeSH
• virové vakcíny imunologie   farmakologie   MeSH
• virus vakcinie genetika   imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH