RT Journal Article
SR Electronic
T1 Separation of resistance to antitumor diarylsulfonylurea agents from collateral sensitivity to mitochondrial toxins.
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 595
OP 601
VO 49
IS 4
A1 Shu, L L
A1 Houghton, P J
YR 1996
UL http://molpharm.aspetjournals.org/content/49/4/595.abstract
AB Compared with parental GC3/c1 human colon adenocarcinoma cells, which are diarylsulfonylurea (DSU)-sensitive cells, the DSU-resistant clone LYC5 demonstrates 4.2-, 12.8-, and 5.3- fold increase in sensitivity to the mitochondrial toxins rotenone, antimycin, and oligomycin, respectively. Studies with hybrids formed by fusion of parental GC3/c1 cells with LYC5 cells have indicated that resistance to antitumor DSUs and collateral sensitivity to mitochondrial toxins are recessive and therefore potentially linked. To examine this, we transfected a cDNA library from GC3/c1 cells, constructed in pcDNA3, into LYC5 cells. G418-resistant colonies were selected and further selected in a single step for resistance to rotenone (100 nm). Individual colonies (designated T5LR) were expanded and tested for sensitivity to mitochondrial toxins, antitumor DSU agents (LY195779 and LY186391) that demonstrate a 45-50-fold differential potency against GC3/c1, LYC5 cells, and the antimitotic agent vincristine. Results demonstrate that resistance to mitochondrial toxins rotenone, antimycin, and oligomycin can be transferred without conferring a DSU-sensitive phenotype. Furthermore, in T5LR clones, resistance to mitochondrial toxins was not associated with increased resistance to vincristine or increased P-glycoprotein expression, supporting the contention that resistance to these agents is independent of P-glycoprotein. Southern blot analysis of T5LR clones demonstrated unique integration sites for the neomycin phosphotransferase gene into genomic DNA in clones 4 and 9, indicating independent derivation. Analysis of clones 4, 6, and 9 with use of polymerase chain reaction demonstrated a cDNA insert of approximately 1.0 kilobase.