In vitro effects of gossypol on testicular lactic dehydrogenase-X and other dehydrogenases

IDH mutations in glioma and acute myeloid leukemia

The systematic sequencing of glioblastoma multiforme (GBM) genomes has identified the recurrent mutation of IDH1, a gene encoding NADP(+)-dependent isocitrate dehydrogenase 1 (IDH1) that catalyzes the oxidative decarboxylation of isocitrate yielding alpha-ketoglutarate (alpha-KG). Subsequent studies have confirmed recurrent IDH1 and IDH2 mutations in up to 70% of low-grade glioma and secondary GBM, as well as in 10% of acute myeloid leukemia (AML) cases. The heterozygous somatic mutations at arginine R132 (IDH1) and at R140 or R172 (IDH2) in the enzyme active site confer a gain of function to the enzymes, which can both produce the metabolite 2-hydroxyglutarate. This review surveys the prevalence of IDH mutations in cancer and explores current mechanistic understanding of IDH mutations with implications for diagnostic and therapeutic development for the treatment of gliomas and AML.

Inhibition of sialyl transferase activity by gossypol acetic acid in human seminal plasma

Seventeen aliquots of 15 microliters seminal plasma of human origin were incubated with 25 micrograms, 15 micrograms, 5 micrograms and 2.5 micrograms gossypol acetic acid (GAA), dissolved in BWW containing 0.9% sodium chloride and 0.9% benzyl alcohol, at 37 degrees C for 60 minutes. Following incubation, activity of sialyl transferase (S.T.) was determined by a procedure involving incorporation of radioactive sialic acid into asialofetuin. The activity of S.T., expressed as cpm per hour per 15 microliters seminal plasma was compared to controls consisting in incubation of sperm in BWW containing 0.9% benzyl alcohol and 0.9% sodium chloride. The activity of S.T. in controls represented 61.3 +/- 8.0%-67.7 +/- 8.9% of the activity obtained by incubation with BWW only. GAA was found to exert a dose-dependent inhibition of S.T. activity, ranging from 38.3 +/- 20.6% to 53.4 +/- 19.4% (with 25 micrograms) and from 11.3 +/- 14.8% to 21.9 +/- 14.8% (with 2.5 micrograms).

Interaction of gossypol with amino acids and peptides as a model of enzyme inhibition

In order to clarify the interaction of gossypol with proteins, the pure diastereoisomeric Schiff bases from L-tryptophan methyl ester and both gossypol enantiomers were prepared. Their c.d. and n.m.r. spectra demonstrate that the interaction between gossypol and tryptophan, previously reported to involve a weakly associated complex, consists in Schiff base formation. Recent studies on enzyme inhibition by gossypol are discussed; it is suggested that nonspecific covalent binding of gossypol to proteins may be responsible for a significant proportion of the in vitro effects of gossypol.