Structure-Based Development of Small Molecule PFKFB3 Inhibitors: A Framework for Potential Cancer Therapeutic Agents Targeting the Warburg Effect

Abstract

Cancer cells adopt glycolysis as the major source of metabolic energy production for fast cell growth. The HIF-1-induced PFKFB3 plays a key role in this adaptation by elevating the concentration of Fru-2,6-BP, the most potent glycolysis stimulator. As this metabolic conversion has been suggested to be a hallmark of cancer, PFKFB3 has emerged as a novel target for cancer chemotherapy. Here, we report that a small molecular inhibitor, N4A, was identified as an initial lead compound for PFKFB3 inhibitor with therapeutic potential. In an attempt to improve its potency, we determined the crystal structure of the PFKFB3•N4A complex to 2.4 Å resolution and, exploiting the resulting molecular information, attained the more potent YN1. When tested on cultured cancer cells, both N4A and YN1 inhibited PFKFB3, suppressing the Fru-2,6-BP level, which in turn suppressed glycolysis and, ultimately, led to cell death. This study validates PFKFB3 as a target for new cancer therapies and provides a framework for future development efforts.

MicroRNA-26b inhibits osteosarcoma cell migration and invasion by down-regulating PFKFB3 expression

“…This enzyme mainly exists in the human brain and placenta, and is present in a wide variety of tumor cell lines. It can decompose glycolysis 6-phosphoric acid to glycerol 3 phosphate, causing glucose to be quickly absorbed for tumor glycolysis and provides energy and materials for tumor proliferation (Seo et al, 2011). It also plays an important role in tumor occurrence and development as a proto-oncogene.…”

PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2)

“…In addition, other small molecule inhibitors (N4A, YN1) have been identified. When tested on cultured cancer cells both, N4A and YN1, inhibited PFKFB3, decreasing Fru-2,6-P 2 concentration and glycolysis and, ultimately, led to cell death (Seo et al, 2011).…”

“…Targeted Knockdown of PFKFB3 limited cell growth under normoxic and hypoxic conditions and blocked in vivo tumor formation in mice (Reddy et al, 2012). Clinical development of PFKFB3 inhibitors as chemotherapeutic agents has been published (Clem et al, 2008, Seo et al, 2011. For example, a cell-permeable dipyridinyl-propenone (3PO) compound that selectively blocks PFK-2 (6-phosphofructo-2-kinase) activity has been found (Telang et al, 2006).…”

6-phosphofructo-2-kinase inhibition induces autophagy as a survival mechanism.

“…The interest in PFKFB3 as a drug target for cancer treatment has now resulted in the identification of small molecule inhibitors of enzyme activity [53,76]. Molecular modeling allowed for the computational screening of a large number compounds with the potential to bind the fructose-6-phosphate binding pocket of PFKFB3.…”

“…The interest in PFKFB3 as an anti-tumor target has resulted in the development of a number of small molecule inhibitors against the enzyme [53,76] of which some are in the process of entering Phase I clinical trials as anticancer therapeutics.…”