Effect of metabolic inhibitors on ATP and citrate content in PC3 prostate cancer cells.
BACKGROUND
In normal prostate epithelial cells low m-aconitase activity decreases citrate oxidation leading to citrate accumulation. In prostate cancer cells m-aconitase activity is increased and citrate content is lower. The effect of inhibition of m-aconitase on ATP production by prostate cancer cells (PC3) is not known nor is the contribution of glycolysis versus respiration.


METHODS
ATP content of PC3 cells as affected by inhibition of m-aconitase (fluoroacetate (FA), zinc), inhibition of glycolysis (2DxG), or respiration (DNP, oligomycin) was determined. The ability to maintain ATP using glucose or glutamine as sole substrate was also determined. Intermediates including ATP, lactate, glucose, and glutamine were assayed in neutralized perchloric acid (PCA) cell extracts, virgin, and conditioned medium by enzymatic fluorometry.


RESULTS
Data show that inhibition of m-aconitase, glycolysis, or respiration alone did not decrease ATP content. Inhibition of both glycolysis and respiration were required to decrease ATP content. PC3 cells were able to produce ATP with either glucose or glutamine as sole substrate. Though FA clearly inhibited m-aconitase there was no evidence that zinc had a similar effect.


CONCLUSIONS
PC3 cells can support ATP production when m-aconitase is inhibited by using glycolysis or oxidation of substrate (e.g., glutamine) entering the TCA cycle distal to citrate.
Matheson
B K
BK
Department of Biomedical Sciences, University of Maryland Dental School, Baltimore, Maryland 21201, USA. bmatheson@umaryland.edu
Adams
J L
JL
Zou
J
J
Patel
R
R
Franklin
R B
RB
D000154:Aconitate Hydratase / Q000037:antagonists & inhibitors; D000255:Adenosine Triphosphate / Q000032:analysis*; D000963:Antimetabolites / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019343:Citric Acid / Q000032:analysis*; D003847:Deoxyglucose / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005463:Fluoroacetates / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects; D006801:Humans; D008297:Male; D009840:Oligomycins / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011471:Prostatic Neoplasms / Q000737:chemistry*; D015032:Zinc / Q000494:pharmacology
D000963:Antimetabolites; D004140:Dinitrophenols; D004791:Enzyme Inhibitors; D005463:Fluoroacetates; D009840:Oligomycins; D019343:Citric Acid; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; C014815:fluoroacetic acid; D000154:Aconitate Hydratase; D015032:Zinc