engleski

Purine nucleoside phosphorylase gene expression in response to 9-deazaguanine and its derivative in human leukemia and lymphoma cells

Recent studies of cytotoxic activity of 9-deazaguanine (9-DG) and its derivative, 1-methyl-9-deazaguanine (AG-19-K1) showed promise inhibitory effects against leukemia and lymphoma cells. Their potent intracellular target could be purine nucleoside phosphorylase (PNP), which is overexpressed in the most of T-cells diseases. Three leukemia and lymphoma cell lines (K562, JURKAT and HuT78) were treated by 9-DG and AG-19-K1 during 6, 12 and 24h. PNP enzymatic activity was analyzed in cell lysates using TLC with [8-14C]inosine as a substrate. Expression of pnp, caspase-3 and p53 gene was assayed by RT-PCR. After cell fixation and PI dye cell cycle was also analyzed. Exposure of cells to compounds caused statistically significant (p<0.05) decrease of pnp gene expression in all treated cells in a time-dependent manner. AG-19-K1 increased expression of caspase-3 in HuT78 cells while p53 was not expressed. On the contrary, in JURKAT cells, AG-19-K1 increased expression of p53 after 6 and 24h of treatment. Cell cycle analyses of K562 showed that both substances led to the cell arrest in G1/G0 phase after 12h of treatment. Although novel compounds were synthesized as potential PNP inhibitors, they had no influence on PNP catalytic activity. 9-dezagvanine and its derivative change expression of pnp gene and have influence on purine salvage pathway in human leukemia and lymphoma cells. For better understanding further investigation is needed.

9-deazaguanine derivative; PNP; gene expression; cell cycle; enzyme activity

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