Identification of small molecule inhibitors of pyruvate kinase M2

Abstract

A common feature of tumors arising from diverse tissue types is a reliance on aerobic glycolysis for glucose metabolism. This metabolic difference between cancer cells and normal cells could be exploited for therapeutic benefit in patients. Cancer cells universally express the M2 isoform of the glycolytic enzyme pyruvate kinase (PKM2), and previous work has demonstrated that PKM2 expression is necessary for aerobic glycolysis and cell proliferation in vivo. Because most normal tissues express an isoform of pyruvate kinase other than PKM2, selective targeting of PKM2 provides an opportunity to target cell metabolism for cancer therapy. PKM2 has an identical catalytic site as the related M1 splice variant (PKM1). However, isoform selective inhibition is possible as PKM2 contains a unique region for allosteric regulation. We have screened a library of greater than 100,000 small molecules to identify such inhibitors. The inhibitors identified for PKM2 fell primarily into three distinct structural classes. The most potent PKM2 inhibitor resulted in decreased glycolysis and increased cell death following loss of growth factor signaling. At least part of this effect was due to on-target PKM2 inhibition as less cell death was observed in cells engineered to express PKM1. These data suggest that isoform selective inhibition of PKM2 with small molecules is feasible and support the hypothesis that inhibition of glucose metabolism in cancer cells is a viable strategy to treat human malignancy.

Shikonin and its analogs inhibit cancer cell glycolysis by targeting tumor pyruvate kinase-M2

“…Although allosteric activation of enzyme activities by FBP is concentration dependent (Figure 3a), we used FBP (125 mM) for the enzyme assay. First, FBP (125 mM) significantly activated PKM2 (Figure 3a), so that the results of this study could be compared with the reported data (Vander Heiden et al, 2010). In fact, the IC 50 of compound-3 determined in this study is similar to the reported data.…”

“…Shikonin and its enantiomeric alkannin are potent inhibitors of PKM2 but not PKM1 and PKL An enzyme assay was performed according to the reported method for identification of compound-3 (N-(3-carboxy-4-hydroxy)phenyl-2,5,-dimethylpyrrole) as PKM2 inhibitor, the most potent inhibitor discovered from a screening of over 100 000 compounds (Vander Heiden et al, 2010). Shikonin and alkannin (the optical isomer of shikonin) showed comparable inhibitory activities, more potent than other shikonin analogs (Figures 3b and c).…”

Targeting cancer metabolism: a therapeutic window opens

“…Selection for a less active form of pyruvate kinase may help divert glucose metabolites upstream of pyruvate kinase into biosynthetic pathways 5,97,100 . Efforts have been made to selectively inhibit PKM2 101,102 . Peptide aptamers that promote the less active form of pyruvate kinase have been shown cause energy stress and cell death in cultured cancer cells 101 , and more modest effects were observed using small molecule inhibitors of PKM2 102 .…”

“…Efforts have been made to selectively inhibit PKM2 101,102 . Peptide aptamers that promote the less active form of pyruvate kinase have been shown cause energy stress and cell death in cultured cancer cells 101 , and more modest effects were observed using small molecule inhibitors of PKM2 102 . Targeting PKM2 with shRNA can slow cell proliferation in cell culture 99 , however these cells retain the ability to proliferate even with the near complete absence of pyruvate kinase activity.…”

In-silico designing of hnRNP B1 inhibitors against lung cancer: a computational approach

“…The L gene is spliced to produce the L and R isoform (mainly expressed in liver and red blood cells respectively) while the M gene splices to form the M1 or M2 isoforms of pyruvate kinase. It has been reported that tumor cells overexpress PKM2 [10] .…”