Untitled

Abstract

Gene therapy is used to induce immune responses, regulate tumor growth, or sensitize tumor cells to specific treatment. For sensitizing tumor cells to specific drug, we considered a prodrug-converting system using membrane-bound intestinal alkaline phosphatase (IAP) as the prodrug-activating genes. The IAP is capable of converting a relatively non-cytotoxic prodrug, etoposide phosphate (EP), into etoposide with a significant antitumor activity. We used the retroviral vector for transducing IAP gene into SNU638 gastric cancer cells and EP was prepared by phosphorylation of etoposide. To determine the chromosomal incorporation of membrane-bound IAP gene and AP activity in IAP gene-transduced cells (SNU638/IAP), we performed genomic PCR and AP activity analysis. In genomic DNA of SNU638/IAP cells, full cDNA fragment of a 2.5 kb IAP was detected, and AP activity was shown at most 15 approximately 18-fold increase compared with control cells. According to the in vitro cytotoxicity study, SNU638/IAP cells greatly enhanced the cytotoxic effect in proportion to the concentration of EP, while control cells didn't cause any cytotoxic effects after EPtreatment. Especially, the cell population of G2/M phase was increased in EP-treated SNU638/ IAP cells because P4 DNA unknotting activity of topoisomerase II was decreased by EP treatment such as the action mechanism of etoposide. Finally, a strong antitumor response was observed in SNU638/IAP cancer cells-bearing nude mice that were treated with EP. These results suggest that the prodrug-converting system by membrane-bound IAP gene and EP prodrug is useful as the strong strategy of gene therapy for cancer treatment.

cPLA2α Enzyme Inhibition Attenuates Inflammation and Keratinocyte Proliferation

“…As a positive control, cells were treated with etoposide, a chemotherapy drug known to block cell cycle progression in HaCaT cells [ 59 , 60 , 61 ]. As expected, treatment with the etoposide (10 µM) caused a decrease in cell numbers that, in contrast to AVX001, was associated with an accumulation of cells in G2/M, and an increased proportion of apoptotic cells, consistent with its known effect as a blocker of the G2/M transition [ 62 , 63 ].…”

“…As a positive control, cells were treated with etoposide, a chemotherapy drug known to block cell cycle progression in HaCaT cells [59][60][61]. As expected, treatment with the etoposide (10 µM) caused a decrease in cell numbers that, in contrast to AVX001, was associated with an accumulation of cells in G2/M, and an increased proportion of apoptotic cells, consistent with its known effect as a blocker of the G2/M transition [62,63]. Treatment with EGF for 24 h did not significantly impact cell viability (not shown), but rather Treatment with EGF for 24 h did not significantly impact cell viability (not shown), but rather led to an increase in the proportion of cells in S-phase of the cell cycle (proliferation index), which was inhibited by AVX001 (≥5 µM) (Figure 3C).…”