id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-270637-4zphlpks	Van Rompay, An R	Substrate specificity and phosphorylation of antiviral and anticancer nucleoside analogues by human deoxyribonucleoside kinases and ribonucleoside kinases	2003-11-04		.txt	text/plain	11595	702	47	(2001) , there are 3 general mechanisms of resistance to NAs that have been described in cell lines and clinical samples: (1) insufficient intracellular concentrations of NA-TPs, which might be due to inefficient cellular uptake, decreased levels of activating enzymes, increased catabolism by elevated levels of 5V -NT or deaminases, or expansion of dNTP pools; (2) inability to achieve sufficient alterations in DNA strands or dNTP pools, which might result from altered interactions with DNA polymerases, lack of inhibition of RR, or inadequate p53 exonuclease activity; and (3) defective induction of apoptosis. In human leukemia cell lines is CAFdA, a more efficient substrate for dCK, and the active form is more stable due to higher phosphorylation and longer retention time compared with CdA, but the mechanisms leading to acquired resistance to CAFdA seem to be similar to those for CdA (Lotfi et al., 1999; Månsson et al., 2003) .	./cache/cord-270637-4zphlpks.txt	./txt/cord-270637-4zphlpks.txt