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This study aimed to evaluate the capacity of hypocalcemic analogues of 1α,25-dihydroxyvitamin D2 (1,25D2) and 1α,25-dihydroxyvitamin D3 (1,25D3) to inhibit regrowth and regulate the stemness-related gene expression in colon cancer cells undergoing renewal after exposure to 5-fluorouracil (5-FU). All of the tested analogues of 1,25D2 equally potently decreased the clonogenicity and the proliferative activity of HT-29 cells which survived the exposure to 5-FU, but differently regulated gene expression of these cells during their renewal. 1,25D2 and analogues (PRI-1907 and PRI-1917), as well as 1,25D3 and analogue PRI-2191, decreased the relative expression level of several stemness-related genes, such as NANOG, OCT3/4, PROM1, SOX2, ALDHA1, CXCR4, in HT-29/5-FU cells during their renewal, in comparison to untreated HT-29/5-FU cells. The other 1,25D2 analogues (PRI-1906 and PRI-1916) were not capable of downregulating the expression of these stemness-related genes as the analogues PRI-1907 and PRI-1917 did. All of the tested vitamin D analogues upregulated CDH1, the gene encoding E-cadherin associated with epithelial phenotype. Out of the series of analogues studied, side-chain branched analogues of 1,25D2 (PRI-1907, PRI-1917) and the analogue of 1,25D3 (PRI-2191) might be used to target cancer cells with stem-like phenotypes that survive conventional chemotherapy. [ABSTRACT FROM AUTHOR]

This study was aimed to determine whether hypocalcemic analogs of active forms of vitamins D modulate expression of genes related to stem-like phenotype in colon cancer cell lines HT-29 and HCT-116 undergoing renewal after the treatment with 5-fluorouracil (5-FU). Both lines express vitamin D receptor, but differ in differentiation stage and vitamin D sensitivity. Cells that resisted the 5-FU exposure were treated with synthetic analog of 1,25-dihydroxyvitamin D (PRI-1906) and analogs of 1,25-dihydroxyvitamin D (PRI-2191 and PRI-2205). Proliferative activity was more profoundly affected by vitamin D analogs in HT-29/5-FU than in HCT-116/5-FU cells. In HT-29/5-FU cells, analogs PRI-1906 and PRI-2191 downregulated the expression of genes related to survival, re-growth, and invasiveness during renewal, while PRI-2205 increased expression of genes related to differentiation only. In HCT-116/5-FU cells, PRI-2191 decreased the expression of stemness- and angiogenesis-related genes, whereas PRI-1906 augmented their expression. The effects in HCT-116/5-FU cells were observed at higher concentrations of the analogs than those used for HT-29/5-FU cells. Out of the series of analogs studied, PRI-2191 might be used to counteract the renewal of both moderately and poorly differentiated cancer cells following conventional treatment. [ABSTRACT FROM AUTHOR]

This study was aimed to determine whether hypocalcemic analogs of active forms of vitamins D modulate expression of genes related to stem-like phenotype in colon cancer cell lines HT-29 and HCT-116 undergoing renewal after the treatment with 5-fluorouracil (5-FU). Both lines express vitamin D receptor, but differ in differentiation stage and vitamin D sensitivity. Cells that resisted the 5-FU exposure were treated with synthetic analog of 1,25-dihydroxyvitamin D2 (PRI-1906) and analogs of 1,25-dihydroxyvitamin D3 (PRI-2191 and PRI-2205). Proliferative activity was more profoundly affected by vitamin D analogs in HT-29/5-FU than in HCT-116/5-FU cells. In HT-29/5-FU cells, analogs PRI-1906 and PRI-2191 downregulated the expression of genes related to survival, re-growth, and invasiveness during renewal, while PRI-2205 increased expression of genes related to differentiation only. In HCT-116/5-FU cells, PRI-2191 decreased the expression of stemness- and angiogenesis-related genes, whereas PRI-1906 augmented their expression. The effects in HCT-116/5-FU cells were observed at higher concentrations of the analogs than those used for HT-29/5-FU cells. Out of the series of analogs studied, PRI-2191 might be used to counteract the renewal of both moderately and poorly differentiated cancer cells following conventional treatment.

Recombinant adeno-associated virus vectors (rAAV) represent a most promising gene delivery vehicles for gene therapy applications because their unique properties, such as capability to infect both proliferating and non proliferating cells of broad host range, and possibilities of long-term expression and site-specific integration. rAAV are also described as vectors neither toxic nor pathogenic to the cells. rAAV vectors are also thought to be attractive for cancer gene therapy. Here, we used rAAV2 vectors encoding reporter genes, rAAV/GFP and rAAV/LacZ to transduce cancer cells. The rAAV preparations were produced by a transient triple AAV plasmid transfection of AAV-293 packaging cells and isolated/purified by iodixanol-gradient method. We report a different rAAV transduction efficiency of the two cancer cell lines cells--ovarian carcinoma (OVP 10) and hepatocellular carcinoma (C3A) cells. The expression of the reporter genes due to rAAV uptake was about two fold higher for ovarian cells than for hepatocellular cells. Our studies have also revealed the long-term expression of GFP gene in hepatocellular (C3A) rAAV/GFP transduced cells. These findings indicate that adeno-associated virus derived vectors could be very useful for cancer gene therapy applications, however, further investigations of the mechanisms of rAAV gene delivery are still needed.

Angiogenic gene therapy is thought to be a new method for the treatment for vascular diseases. Plasmid preparations encoding angiogenic factors like a vascular endothelial growth factor (VEGF) or a fibroblast growth factor (FGF) effectively stimulate the formation of new vessels. The first clinical trials with novel angiogenic drugs--genetic preparations have already been reported. Nevertheless, gene transfer and expression efficiency still require a lot of experimental work. Here, three different angiogenic preparations were studied. We used monocistronic vectors encoding VEGF165 or FGF-2 and bicistronic construct expressing both of them. The angiogenic potency of the plasmids was evaluated by in vivo angiogenesis tests. We also tested the plasmid DNA maintenance in mouse tissue as well as the transcriptional activity of the angiogenic preparations. We saw that all plasmids effectively stimulate the formation of new vessels in in vivo conditions up to 20 days. The most powerfull angiogenic potency was demonstrated by the bicistronic vector. It was shown that after 3, 13, 21, 31 and 41 days post-transfection the plasmid DNA still persisted in tissue, more or less on the same level but the mRNA transcripts after 13 days slowly decreased. This work confirmed effectiveness of gene therapy, and gave new information about angiogenic plasmid preparations useful for practical applications.