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Effects of the Anti‐Tumor Agent 3‐Bromopyruvate (3BrPA) on Glycolytic Energy Metabolism
Author(s) -
Robey R. Brooks,
Hong Richard,
Zhong Lihui,
Feng Lanfei,
Zhang Hongmei
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1190-a
Subject(s) - glycolysis , iodoacetamide , biochemistry , chemistry , glyceraldehyde 3 phosphate dehydrogenase , cell culture , lactate dehydrogenase , hexokinase , metabolism , enzyme , adenosine triphosphate , cancer cell , ic50 , in vitro , biology , dehydrogenase , cysteine , cancer , genetics
BACKGROUND & METHODS: 3BrPA has been reported to eradicate liver cancer in animals without associated systemic toxicity. The molecular basis of this effect is incompletedly characterized but has been attributed to selective hexokinase (HK) inhibition and ATP depletion. We therefore examined 3BrPA and other alkylating agents ‐ 3‐fluoropyruvate (3FPA), iodoacetate (IAA), and iodoacetamide (IAM) ‐ for the ability to alter glycolytic HK and GAPDH activities, lactate accumulation, ATP content, and cell viability in non‐transformed renal epithelial cells. RESULTS: 3BrPA inhibited HK activity in cell‐free lysates in a concentration‐dependent manner, an effect that was less potently mimicked by IAA (IC 50 8 vs 0.7 mM), but not by pyruvate, 3FPA, or IAM. Monothioglycerol had no effect on basal activity but markedly decreased sensitivity to 3BrPA and IAA inhibition. 3BrPA was also non‐competitive with Glc and ATP. When examined in intact cells, 3BrPA and IAA reduced ATP content and lactate accumulation at μM concentrations that were orders of magnitude lower than those required for HK inhibition in vitro . Cytotoxic LDH release was only observed following profound ATP depletion but was uniformly higher for IAA. Interestingly, 3BrPA inhibited GAPDH more potently than its classic antagonist IAA in cell‐free lysates (IC 50 2.5 vs 150 μM). CONCLUSIONS: 3BrPA inhibits HK activity, presumably via selective alkylation of sulfhydryl groups important for enzymatic function but not involved in Glc or ATP binding. However, 3BrPA glycolytic inhibitory potency correlates better with GAPDH inhibition than with HK inhibition in non‐tumor epithelial cells. IAA ‐ but not 3FPA or IAM ‐ can mimic these effects, albeit with greater relative ATP depletion and cytotoxicity that suggest actions additional to those shared with 3BrPA.