Discovery of N-hydroxyindole-based inhibitors of human lactate dehydrogenase isoform A (LDH-A) as starvation agents against cancer cells

Detection of protein-small molecule binding using a self-referencing external cavity laser biosensor

High-throughput screening has enabled the identification of small molecule modulators of important drug targets via well-established colorimetric or fluorimetric activity assays. However, existing methods to identify small molecule binders of nonenzymatic protein targets lack either the simplicity (e.g., require labeling one of the binding partners with a reporter) or throughput inherent in enzymatic assays widely used for HTS. Thus, there is intense interest in the development of high-throughput technologies for label-free detection of protein-small molecule interactions. Here we describe a novel self-referencing external cavity laser (ECL) biosensor approach that achieves high resolution and high sensitivity, while eliminating thermal noise with subpicometer wavelength accuracy. Using the self-referencing ECL biosensor, we demonstrate detection of binding between small molecules and a variety of immobilized protein targets, pairs that have binding affinities or inhibition constants ranging from subnanomolar to low micromolar. Finally, a "needle-in-the-haystack" screen for inhibitors against carbonic anhydrase isozyme II is performed, in which known inhibitors are clearly differentiated from inactive molecules within a compound library.

Metabolic implication of tumor:stroma crosstalk in breast cancer

The metabolic properties of cancer cells significantly differ from those of normal cells. In particular, cancer cells are largely dependent on aerobic glycolysis, a phenomenon that has been exploited clinically by using labelled glucose for positron emission tomography imaging. Importantly, cancer-associated alterations in metabolism are not merely due to the resulting response to cell proliferation and survival. Indeed, direct metabolic regulation could be driven by tumor oncogenes and/or suppressors, as demonstrated in several solid tumors, including breast cancer. Despite the fact that most breast cancer studies have focused on the intrinsic characteristics of breast tumor cells, it is now widely accepted that tumor microenvironment plays an important role in defining and reprogramming cancer cell metabolism. Tumor:stroma crosstalk, as well as inflammatory cues, concurs to outlining the cancer metabolism, impact on cancer aggressiveness and ultimately on patient survival and therapeutic responses. The aim of this review is to (i) gather the most recent data regarding the metabolic alterations in breast cancer, (ii) describe the role of tumor microenvironment in breast cancer cell metabolic reprogramming, and (iii) contemplate how targeting metabolic pathways aberrantly activated in breast cancer could help current therapeutic regimens.

Human lactate dehydrogenase a inhibitors: a molecular dynamics investigation

Lactate dehydrogenase A (LDHA) is an important enzyme in fermentative glycolysis, generating most energy for cancer cells that rely on anaerobic respiration even under normal oxygen concentrations. This renders LDHA a promising molecular target for the treatment of various cancers. Several efforts have been made recently to develop LDHA inhibitors with nanomolar inhibition and cellular activity, some of which have been studied in complex with the enzyme by X-ray crystallography. In this work, we present a molecular dynamics (MD) study of the binding interactions of selected ligands with human LDHA. Conventional MD simulations demonstrate different binding dynamics of inhibitors with similar binding affinities, whereas steered MD simulations yield discrimination of selected LDHA inhibitors with qualitative correlation between the in silico unbinding difficulty and the experimental binding strength. Further, our results have been used to clarify ambiguities in the binding modes of two well-known LDHA inhibitors.

Synergistic interaction of novel lactate dehydrogenase inhibitors with gemcitabine against pancreatic cancer cells in hypoxia

BACKGROUND

Hypoxia is a driving force in pancreatic-ductal-adenocarcinoma (PDAC) growth, metastasis and chemoresistance. The muscle-isoform of lactate dehydrogenase (LDH-A) constitutes a major checkpoint for the switch to anaerobic glycolysis, ensuring supply of energy and anabolites in hypoxic-environments. Therefore, we investigated the molecular mechanisms underlying the pharmacological interaction of novel LDH-A inhibitors in combination with gemcitabine in PDAC cells.

METHODS

Lactate dehydrogenase A levels were studied by quantitative RT-PCR, western blot, immunofluorescence and activity assays in 14 PDAC cells, including primary-cell-cultures and spheroids, in normoxic and hypoxic conditions. Cell proliferation, migration and key determinants of drug activity were evaluated by sulforhodamine-B-assay, wound-healing assay, PCR and LC-MS/MS.

RESULTS

Lactate dehydrogenase A was significantly increased under hypoxic conditions (1% O2), where the novel LDH-A inhibitors proved to be particularly effective (e.g., with IC50 values of 0.9 vs 16.3 μM for NHI-1 in LPC006 in hypoxia vs normoxia, respectively). These compounds induced apoptosis, affected invasiveness and spheroid-growth, reducing expression of metalloproteinases and cancer-stem-like-cells markers (CD133+). Their synergistic interaction with gemcitabine, with combination index values <0.4 in hypoxia, might also be attributed to modulation of gemcitabine metabolism, overcoming the reduced synthesis of phosphorylated metabolites.

CONCLUSION

Lactate dehydrogenase A is a viable target in PDAC, and novel LDH-A inhibitors display synergistic cytotoxic activity with gemcitabine, offering an innovative tool in hypoxic tumours.

Dual targeting of the Warburg effect with a glucose-conjugated lactate dehydrogenase inhibitor

Effective glucose diet: We report the development and activity of glucose-conjugated LDH-A inhibitors designed for dual targeting of the Warburg effect (elevated glucose uptake and glycolysis) in cancer cells. Glycoconjugation could be applied to inhibitors of many enzymes involved in glycolysis or tumor metabolism.

Collecting and assessing human lactate dehydrogenase-A conformations for structure-based virtual screening

Human lactate dehydrogenase-A (LDHA) is emerging as a promising anticancer target. Up to now, structure-based investigations for identifying inhibitors of this enzyme have not explicitly accounted for active site flexibility. In the present study, by combining replica exchange molecular dynamics with network and cluster analyses, we identified reliable LDHA conformations for structure-based ligand design. The selected conformations were challenged and validated by retrospective virtual screening simulations.

Lactate dehydrogenase A in cancer: a promising target for diagnosis and therapy

One of the principal biochemical characteristics of malignant cells compared to normal cells is a metabolic switch from oxidative phosphorylation to increased glycolysis, even under hypoxic conditions, and is termed the Warburg effect. Lactate dehydrogenase A (LDHA) catalyzes the conversion of pyruvate to lactate and is considered to be a key checkpoint of anaerobic glycolysis. It is elevated in many types of cancers and has been linked to tumor growth, maintenance, and invasion; therefore, its inhibition may restrict the energy supply in tumors and thereby reduce the metastatic and invasive potential of cancer cells. This enzyme is receiving a great deal of attention as a potential diagnostic marker or a predictive biomarker for many types of cancer and as a therapeutic target for new anticancer treatments. In this review, we summarize the role of LDHA in cancer, discuss its potential significance in clinical diagnosis and prognosis of cancer, and propose LDHA as a novel target for the inhibition of tumor growth and invasiveness.

Inhibition of LDH-A by oxamate induces G2/M arrest, apoptosis and increases radiosensitivity in nasopharyngeal carcinoma cells

An elevated rate of glucose consumption and the dependency on aerobic glycolysis for ATP generation have long been observed in cancer cells, a phenomenon known as the Warburg effect. the altered energy metabolism in cancer cells provides an attractive opportunity for developing novel cancer therapeutic strategies. Lactate dehydrogenase (LDH), which catalyzes the transformation of pyruvate to lactate, plays a vital role in the process of glycolysis. It has been reported that the level of LDH-A expression is increased both in head and neck cancer cells and in the blood serum of nasopharyngeal carcinoma (NPC) patients, and is associated with poor prognosis. However, the effect of LDH-A inhibition on NPC cells remains unknown. Here, in the present study, we found that oxamate, a classical inhibitor of LDH-A, suppressed cell proliferation in a dose- and time-dependent manner both in CNE-1 and CNE-2 cells, two NPC cancer cell lines. LDH inhibition by oxamate induced G2/M cell cycle arrest via downregulation of the CDK1/cyclin B1 pathway and promoted apoptosis through enhancement of mitochondrial ROS generation. N-acetylcysteine, a specific scavenger of ROS, significantly blocked the growth inhibition effect induced by oxamate. We also identified that oxamate increased sensitivity to ionizing radiation in the two NPC cancer cell lines. Furthermore, we verified similar results in tumor xenograft models. collectively, these results suggest that LDH-A may serve as a promising therapeutic target for NPC treatment.

Quinoline 3-sulfonamides inhibit lactate dehydrogenase A and reverse aerobic glycolysis in cancer cells

Background

Most normal cells in the presence of oxygen utilize glucose for mitochondrial oxidative phosphorylation. In contrast, many cancer cells rapidly convert glucose to lactate in the cytosol, a process termed aerobic glycolysis. This glycolytic phenotype is enabled by lactate dehydrogenase (LDH), which catalyzes the inter-conversion of pyruvate and lactate. The purpose of this study was to identify and characterize potent and selective inhibitors of LDHA.

Methods

High throughput screening and lead optimization were used to generate inhibitors of LDHA enzymatic activity. Effects of these inhibitors on metabolism were evaluated using cell-based lactate production, oxygen consumption, and ¹³C NMR spectroscopy assays. Changes in comprehensive metabolic profile, cell proliferation, and apoptosis were assessed upon compound treatment.

Results

3-((3-carbamoyl-7-(3,5-dimethylisoxazol-4-yl)-6-methoxyquinolin-4-yl) amino) benzoic acid was identified as an NADH-competitive LDHA inhibitor. Lead optimization yielded molecules with LDHA inhibitory potencies as low as 2 nM and 10 to 80-fold selectivity over LDHB. Molecules in this family rapidly and profoundly inhibited lactate production rates in multiple cancer cell lines including hepatocellular and breast carcinomas. Consistent with selective inhibition of LDHA, the most sensitive breast cancer cell lines to lactate inhibition in hypoxic conditions were cells with low expression of LDHB. Our inhibitors increased rates of oxygen consumption in hepatocellular carcinoma cells at doses up to 3 microM, while higher concentrations directly inhibited mitochondrial function. Analysis of more than 500 metabolites upon LDHA inhibition in Snu398 cells revealed that intracellular concentrations of glycolysis and citric acid cycle intermediates were increased, consistent with enhanced Krebs cycle activity and blockage of cytosolic glycolysis. Treatment with these compounds also potentiated PKM2 activity and promoted apoptosis in Snu398 cells.

Conclusions

Rapid chemical inhibition of LDHA by these quinoline 3-sulfonamids led to profound metabolic alterations and impaired cell survival in carcinoma cells making it a compelling strategy for treating solid tumors that rely on aerobic glycolysis for survival.

Targeting lactate metabolism for cancer therapeutics

Lactate, once considered a waste product of glycolysis, has emerged as a critical regulator of cancer development, maintenance, and metastasis. Indeed, tumor lactate levels correlate with increased metastasis, tumor recurrence, and poor outcome. Lactate mediates cancer cell intrinsic effects on metabolism and has additional non-tumor cell autonomous effects that drive tumorigenesis. Tumor cells can metabolize lactate as an energy source and shuttle lactate to neighboring cancer cells, adjacent stroma, and vascular endothelial cells, which induces metabolic reprogramming. Lactate also plays roles in promoting tumor inflammation and in functioning as a signaling molecule that stimulates tumor angiogenesis. Here we review the mechanisms of lactate production and transport and highlight emerging evidence indicating that targeting lactate metabolism is a promising approach for cancer therapeutics.

Assessing the differential action on cancer cells of LDH-A inhibitors based on the N-hydroxyindole-2-carboxylate (NHI) and malonic (Mal) scaffolds

A head-to-head study of representative examples of N-hydroxyindole-2-carboxylates (NHI) and malonic derivatives (Mal) as LDH-A inhibitors was conducted, comparing the enzyme inhibition potency, cellular uptake, reduction of lactate production in cancer cells and anti-proliferative activity. Among the compounds tested, methyl 1-hydroxy-6-phenyl-4-(trifluoromethyl)-1H-indole-2-carboxylate (2, NHI-2), a methyl ester belonging to the NHI class, displayed optimal properties in the cell-based assays, proving to be an efficient anti-glycolytic agent against cancer cells.

Identification of 2-amino-5-aryl-pyrazines as inhibitors of human lactate dehydrogenase

A 2-amino-5-aryl-pyrazine was identified as an inhibitor of human lactate dehydrogenase A (LDHA) via a biochemical screening campaign. Biochemical and biophysical experiments demonstrated that the compound specifically interacted with human LDHA. Structural variation of the screening hit resulted in improvements in LDHA biochemical inhibition and pharmacokinetic properties. A crystal structure of an improved compound bound to human LDHA was also obtained and it explained many of the observed structure-activity relationships.

Identification of substituted 2-thio-6-oxo-1,6-dihydropyrimidines as inhibitors of human lactate dehydrogenase

A novel 2-thio-6-oxo-1,6-dihydropyrimidine-containing inhibitor of human lactate dehydrogenase (LDH) was identified by high-throughput screening (IC50=8.1 μM). Biochemical, surface plasmon resonance, and saturation transfer difference NMR experiments indicated that the compound specifically associated with human LDHA in a manner that required simultaneous binding of the NADH co-factor. Structural variation of the screening hit resulted in significant improvements in LDHA biochemical inhibition activity (best IC50=0.48 μM). A crystal structure of an optimized compound bound to human LDHA was obtained and explained many of the observed structure-activity relationships.

Conceptual framework for cutting the pancreatic cancer fuel supply

Pancreatic ductal adenocarcinoma (a.k.a. pancreatic cancer) remains one of the most feared and clinically challenging diseases to treat despite continual improvements in therapies. The genetic landscape of pancreatic cancer shows near ubiquitous activating mutations of KRAS, and recurrent inactivating mutations of CDKN2A, SMAD4, and TP53. To date, attempts to develop agents to target KRAS to specifically kill cancer cells have been disappointing. In this regard, an understanding of cellular metabolic derangements in pancreatic cancer could lead to novel therapeutic approaches. Like other cancers, pancreatic cancer cells rely on fuel sources for homeostasis and proliferation; as such, interrupting the use of two major nutrients, glucose and glutamine, may provide new therapeutic avenues. In addition, KRAS-mutant pancreatic cancers have been documented to depend on autophagy, and the inhibition of autophagy in the preclinical setting has shown promise. Herein, the conceptual framework for blocking the pancreatic fuel supply is reviewed.

Fragment growing and linking lead to novel nanomolar lactate dehydrogenase inhibitors

Lactate dehydrogenase A (LDH-A) catalyzes the interconversion of lactate and pyruvate in the glycolysis pathway. Cancer cells rely heavily on glycolysis instead of oxidative phosphorylation to generate ATP, a phenomenon known as the Warburg effect. The inhibition of LDH-A by small molecules is therefore of interest for potential cancer treatments. We describe the identification and optimization of LDH-A inhibitors by fragment-based drug discovery. We applied ligand based NMR screening to identify low affinity fragments binding to LDH-A. The dissociation constants (K(d)) and enzyme inhibition (IC(50)) of fragment hits were measured by surface plasmon resonance (SPR) and enzyme assays, respectively. The binding modes of selected fragments were investigated by X-ray crystallography. Fragment growing and linking, followed by chemical optimization, resulted in nanomolar LDH-A inhibitors that demonstrated stoichiometric binding to LDH-A. Selected molecules inhibited lactate production in cells, suggesting target-specific inhibition in cancer cell lines.

Anticancer agents that counteract tumor glycolysis

Can we consider cancer to be a "metabolic disease"? Tumors are the result of a metabolic selection, forming tissues composed of heterogeneous cells that generally express an overactive metabolism as a common feature. In fact, cancer cells have increased needs for both energy and biosynthetic intermediates to support their growth and invasiveness. However, their high proliferation rate often generates regions that are insufficiently oxygenated. Therefore, their carbohydrate metabolism must rely mostly on a glycolytic process that is uncoupled from oxidative phosphorylation. This metabolic switch, also known as the Warburg effect, constitutes a fundamental adaptation of tumor cells to a relatively hostile environment, and supports the evolution of aggressive and metastatic phenotypes. As a result, tumor glycolysis may constitute an attractive target for cancer therapy. This approach has often raised concerns that antiglycolytic agents may cause serious side effects toward normal cells. The key to selective action against cancer cells can be found in their hyperbolic addiction to glycolysis, which may be exploited to generate new anticancer drugs with minimal toxicity. There is growing evidence to support many glycolytic enzymes and transporters as suitable candidate targets for cancer therapy. Herein we review some of the most relevant antiglycolytic agents that have been investigated thus far for the treatment of cancer.

Therapeutic targets in cancer cell metabolism and autophagy

The metabolism of cancer cells is reprogrammed both by oncogene signaling and by dysregulation of metabolic enzymes. The resulting altered metabolism supports cellular proliferation and survival but leaves cancer cells dependent on a continuous supply of nutrients. Thus, many metabolic enzymes have become targets for new cancer therapies. Recently, two processes—expression of specific isoforms of metabolic enzymes and autophagy—have been shown to be crucial for the adaptation of tumor cells to changes in nutrient availability. An increasing number of approved and experimental therapeutics target these two processes. A better understanding of the molecular basis of cancer-associated metabolic changes may lead to improved cancer therapies.

Strategic role for mitochondria in Alzheimer's disease and cancer

SIGNIFICANCE

Detailed knowledge about cell death and cell survival mechanisms and how these pathways are impaired in neurodegenerative disorders and cancer forms the basis for future drug development for these diseases that affect millions of people around the world.

RECENT ADVANCES

In neurodegenerative disorders such as Alzheimer's disease (AD), cell death pathways are inappropriately activated, resulting in neuronal cell death. In contrast, cancer cells develop resistance to apoptosis by regulating anti-apoptotic proteins signaling via mitochondria. Mounting evidence shows that mitochondrial function is central in both cancer and AD. Cancer cells typically shut down oxidative phosphorylation (OXPHOS) in mitochondria and switch to glycolysis for ATP production, making them resistant to hypoxia. In AD, for example, amyloid-β peptide (Aβ) and reactive oxygen species impair mitochondrial function. Neurons therefore also switch to glycolysis to maintain ATP production and to produce molecules involved in antioxidant metabolism in an attempt to survive.

CRITICAL ISSUES

One critical difference between cancer cells and neurons is that cancer cells can survive without OXPHOS, while neurons are dependent on OXPHOS for long-term survival.

FUTURE DIRECTIONS

This review will focus on these abnormalities of mitochondrial function shared in AD and cancer and discuss the potential mechanisms underlying links that may be key steps in the development of therapeutic strategies.

Design and synthesis of novel lactate dehydrogenase A inhibitors by fragment-based lead generation

Lactate dehydrogenase A (LDHA) catalyzes the conversion of pyruvate to lactate, utilizing NADH as a cofactor. It has been identified as a potential therapeutic target in the area of cancer metabolism. In this manuscript we report our progress using fragment-based lead generation (FBLG), assisted by X-ray crystallography to develop small molecule LDHA inhibitors. Fragment hits were identified through NMR and SPR screening and optimized into lead compounds with nanomolar binding affinities via fragment linking. Also reported is their modification into cellular active compounds suitable for target validation work.

SIRT1, metabolism and cancer

PURPOSE OF REVIEW

SIRT1 impacts upon diverse cellular processes via its roles in the determination of chromatin structure, chromatin remodelling and gene expression. This review covers the recent discoveries linking SIRT1 with the regulation of mammalian metabolism and considers ways in which abnormal metabolism in disease may, in turn, impact upon SIRT1 because of SIRT1's functional dependency upon NAD.

RECENT FINDINGS

Diverse signalling pathways are integrated to regulate energy metabolism and homeostasis. Such pathways involve intracellular networks and mitochondria, and also intercellular signalling within and between tissues to co-ordinate adaptive metabolic responses within the organism as a whole. Here, we outline the recent studies exploring the regulatory links between SIRT1 and mitochondrial biogenesis, cellular redox and associated metabolic pathways, and angiogenesis/Notch signalling. These links are effected by the SIRT1-mediated deacetylation of transcriptional regulators and enzymes with key roles in metabolism.

SUMMARY

SIRT1 activity is directly coupled with homeostasis and metabolism. SIRT1 is also a metabolic sensor. It follows that disease-related metabolic abnormalities are likely to impinge upon SIRT1 functioning. Disease-related functions of SIRT1, in their turn, offer potential targets for the development of novel SIRT1-based therapies. In cancer, for example, the survival function of SIRT1 may reflect abnormal cancer metabolism and identifies SIRT1 as a target for anticancer therapy.

Targeting the metabolic microenvironment of tumors

The observation of aerobic glycolysis by tumor cells in 1924 by Otto Warburg, and subsequent innovation of imaging glucose uptake by tumors in patients with PET-CT, has incited a renewed interest in the altered metabolism of tumors. As tumors grow in situ, a fraction of it is further away from their blood supply, leading to decreased oxygen concentrations (hypoxia), which induces the hypoxia response pathways of HIF1α, mTOR, and UPR. In normal tissues, these responses mitigate hypoxic stress and induce neoangiogenesis. In tumors, these pathways are dysregulated and lead to decreased perfusion and exacerbation of hypoxia as a result of immature and chaotic blood vessels. Hypoxia selects for a glycolytic phenotype and resultant acidification of the tumor microenvironment, facilitated by upregulation of proton transporters. Acidification selects for enhanced metastatic potential and reduced drug efficacy through ion trapping. In this review, we provide a comprehensive summary of preclinical and clinical drugs under development for targeting aerobic glycolysis, acidosis, hypoxia and hypoxia response pathways. Hypoxia and acidosis can be manipulated, providing further therapeutic benefit for cancers that feature these common phenotypes.

Galloflavin (CAS 568-80-9): a novel inhibitor of lactate dehydrogenase

One of the most prominent alterations in cancer cells is their strict dependence on the glycolytic pathway for ATP generation. This observation led to the evaluation of glycolysis inhibitors as potential anticancer agents. The inhibition of lactate dehydrogenase (LDH) is a promising way to inhibit tumor cell glucose metabolism without affecting the energetic balance of normal tissues. However, the success of this approach depends chiefly on the availability of inhibitors that display good selectivity. We identified a compound (galloflavin, CAS 568-80-9) which, in contrast to other inhibitors of human LDH, hinders both the A and B isoforms of the enzyme. To determine the mechanism of action, we collected LDH-A and -B inhibition data in competition reactions with pyruvate or NADH and evaluated the results using software for enzyme kinetics analysis. We found that galloflavin inhibits both human LDH isoforms by preferentially binding the free enzyme, without competing with the substrate or cofactor. The calculated Ki values for pyruvate were 5.46 μM (LDH-A) and 15.06 μM (LDH-B). In cultured tumor cells, galloflavin blocked aerobic glycolysis at micromolar concentrations, did not interfere with cell respiration, and induced cell death by triggering apoptosis. To our knowledge, the inhibition of LDH is, to date, the only biochemical effect described for galloflavin. Because galloflavin is not commercially available, we also describe herein a procedure for its synthesis and report its first full chemical characterization.

N-Hydroxyindole-based inhibitors of lactate dehydrogenase against cancer cell proliferation

Current cancer research is being increasingly focused on the study of distinctive characters of tumour metabolism, resulting in a switch from oxidative phosphorylation to glycolysis (Warburg effect). Isoform 5 of human lactate dehydrogenase (hLDH5), which catalyzes the final step in the glycolytic cascade (pyruvate to lactate), constitutes a relatively new and untapped anti-cancer target. In this study, careful design and synthesis of a selected series of aryl-substituted N-hydroxyindole-2-carboxylates (NHIs) has led to several hLDH5-inhibitors, showing "first-in-class" potency and isoform selectivity. Enzyme kinetics studies indicated that these inhibitors exhibit a competitive mode of inhibition. Some representative examples were tested against two human pancreatic carcinoma cell lines, and displayed a good anti-proliferative activity, which was even more evident under hypoxic conditions.

Synthesis of sulfonamide-containing N-hydroxyindole-2-carboxylates as inhibitors of human lactate dehydrogenase-isoform 5

N-Hydroxyindole-2-carboxylates possessing sulfonamide-substituents at either position 5 or 6 were designed and synthesized. The inhibitory activities of these compounds against isoforms 1 and 5 of human lactate dehydrogenase were analysed, and K(i) values of the most efficient inhibitors were determined by standard enzyme kinetic studies. Some of these compounds displayed state-of-the-art inhibitory potencies against isoform 5 (K(i) values as low as 5.6 μM) and behaved as competitive inhibitors versus both the substrate and the cofactor.

Anticancer targets in the glycolytic metabolism of tumors: a comprehensive review

CANCER IS A METABOLIC DISEASE AND THE SOLUTION OF TWO METABOLIC EQUATIONS: to produce energy with limited resources and to fulfill the biosynthetic needs of proliferating cells. Both equations are solved when glycolysis is uncoupled from oxidative phosphorylation in the tricarboxylic acid cycle, a process known as the glycolytic switch. This review addresses in a comprehensive manner the main molecular events accounting for high-rate glycolysis in cancer. It starts from modulation of the Pasteur Effect allowing short-term adaptation to hypoxia, highlights the key role exerted by the hypoxia-inducible transcription factor HIF-1 in long-term adaptation to hypoxia, and summarizes the current knowledge concerning the necessary involvement of aerobic glycolysis (the Warburg effect) in cancer cell proliferation. Based on the many observations positioning glycolysis as a central player in malignancy, the most advanced anticancer treatments targeting tumor glycolysis are briefly reviewed.