Understanding the Contribution of Lactate Metabolism in Cancer Progress: A Perspective from Isomers

Dichloroacetate for Cancer Treatment: Some Facts and Many Doubts

Rarely has a chemical elicited as much controversy as dichloroacetate (DCA). DCA was initially considered a dangerous toxic industrial waste product, then a potential treatment for lactic acidosis. However, the main controversies started in 2008 when DCA was found to have anti-cancer effects on experimental animals. These publications showed contradictory results in vivo and in vitro such that a thorough consideration of this compound's in cancer is merited. Despite 50 years of experimentation, DCA's future in therapeutics is uncertain. Without adequate clinical trials and health authorities' approval, DCA has been introduced in off-label cancer treatments in alternative medicine clinics in Canada, Germany, and other European countries. The lack of well-planned clinical trials and its use by people without medical training has discouraged consideration by the scientific community. There are few thorough clinical studies of DCA, and many publications are individual case reports. Case reports of DCA's benefits against cancer have been increasing recently. Furthermore, it has been shown that DCA synergizes with conventional treatments and other repurposable drugs. Beyond the classic DCA target, pyruvate dehydrogenase kinase, new target molecules have also been recently discovered. These findings have renewed interest in DCA. This paper explores whether existing evidence justifies further research on DCA for cancer treatment and it explores the role DCA may play in it.

Metabolic coordination between skin epithelium and type 17 immunity sustains chronic skin inflammation

Inflammatory epithelial diseases are spurred by the concomitant dysregulation of immune and epithelial cells. How these two dysregulated cellular compartments simultaneously sustain their heightened metabolic demands is unclear. Single-cell and spatial transcriptomics (ST), along with immunofluorescence, revealed that hypoxia-inducible factor 1α (HIF1α), downstream of IL-17 signaling, drove psoriatic epithelial remodeling. Blocking HIF1α in human psoriatic lesions ex vivo impaired glycolysis and phenocopied anti-IL-17 therapy. In a murine model of skin inflammation, epidermal-specific loss of HIF1α or its target gene, glucose transporter 1, ameliorated epidermal, immune, vascular, and neuronal pathology. Mechanistically, glycolysis autonomously fueled epithelial pathology and enhanced lactate production, which augmented the γδ T17 cell response. RORγt-driven genetic deletion or pharmacological inhibition of either lactate-producing enzymes or lactate transporters attenuated epithelial pathology and IL-17A expression in vivo. Our findings identify a metabolic hierarchy between epithelial and immune compartments and the consequent coordination of metabolic processes that sustain inflammatory disease.

Engineered Bacillus subtilis as oral probiotics to enhance clearance of blood lactate

Elevated lactate concentrations are implicated in various acute and chronic diseases such as sepsis and mitochondrial dysfunction, respectively. Conversely, ineffective lactate clearance is associated with poor clinical prognoses and high mortality in these diseases. While several groups have proposed using small molecule inhibitors and enzyme replacement to reduce circulating lactate, there are few practical and effective ways to manage this condition. Recent evidence suggests that lactate is exchanged between systemic circulation and the gut, allowing bidirectional modulation between the gut microbiota and peripheral tissues. Inspired by these findings, this work seeks to engineer spore-forming probiotic B. subtilis strains to enable intestinal delivery of lactate oxidase as a therapeutic enzyme. After strain optimization, we showed that oral administration of engineered B. subtilis spores to the gut of mice reduced elevations in blood lactate in two different mouse models involving exogenous challenge or pharmacologic perturbation without disrupting gut microbiota composition, liver function, or immune homeostasis. Taken together, through the oral delivery of engineered probiotic spores to the gastrointestinal tract, our proof-of-concept study offers a practical strategy to aid in the management of disease states with elevated blood lactate and provides a new approach to 'knocking down' circulating metabolites to help understand their roles in host physiological and pathological processes.

Is digit ratio (2D:4D) a biomarker for lactate? Evidence from a cardiopulmonary test on professional male footballers

BACKGROUND

Lactate accumulation is associated with vigorous exercise, cardiovascular disease and a number of cancers. Digit ratio (2D:4D) has also been linked to oxygen metabolism, myocardial infarction and various cancers. Such similarities suggest the possibility that 2D:4D is a biomarker of lactate. Here, we consider the relationship between 2D:4D and lactate during an incremental cardiopulmonary exercise test.

METHOD

The participants were male professional football players. The treadmill test began at a speed of 8 km/h when the first lactate measurement was taken. The speed was increased by 2 km/h every 3.15 min, with measurements at 10, 12, 14 and 16 km/h.

RESULTS

There were 72 Caucasian and 7 Black participants, results are reported for the most numerous group. Lactate levels increased with running speed and were not correlated with age, body size or body composition. Median splits of digit ratios (right, left and right-left 2D:4D [Dr-l]) were calculated. In comparison to the Low ratio group, the High ratio group showed higher lactate levels across speeds. Effect sizes varied from very large to huge (right 2D:4D), large (left 2D:4D) and medium (Dr-l). At the individual level, positive correlations between digit ratios and lactate at the five different speeds varied from large (right 2D:4D), medium (left 2D:4D) and small (Dr-l).

CONCLUSION

There were large positive associations between right 2D:4D and lactate at all running speeds. We discuss our findings in relation to oxygen metabolism and suggest that 2D:4D may be a biomarker for lactate in the wider context of the latter's importance in health and disease.

Mechanistic Investigation of Thiazole-Based Pyruvate Kinase M2 Inhibitor Causing Tumor Regression in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a deadly breast cancer with a poor prognosis. Pyruvate kinase M2 (PKM2), a key rate-limiting enzyme in glycolysis, is abnormally highly expressed in TNBC. Overexpressed PKM2 amplifies glucose uptake, enhances lactate production, and suppresses autophagy, thereby expediting the progression of oncogenic processes. A high mortality rate demands novel chemotherapeutic regimens at once. Herein, we report the rational development of an imidazopyridine-based thiazole derivative 7d as an anticancer agent inhibiting PKM2. Nanomolar range PKM2 inhibitors with favorable drug-like properties emerged through enzyme assays. Experiments on two-dimensional (2D)/three-dimensional (3D) cell cultures, lactate release assay, surface plasmon resonance (SPR), and quantitative real-time polymerase chain reaction (qRT-PCR) validated 7d preclinically. In vivo, 7d outperformed lapatinib in tumor regression. This investigation introduces a lead-based approach characterized by its clear-cut chemistry and robust efficacy in designing an exceptionally potent inhibitor targeting PKM2, with a focus on combating TNBC.

Chiral MOF Derived Wearable Logic Sensor for Intuitive Discrimination of Physiologically Active Enantiomer

Chiral sensors have attracted growing interest due to their application in health monitoring. However, rational design of wearable logic chiral sensors remains a great challenge. In this work, a dual responsive chiral sensor RT@CDMOF is prepared through in situ self-assembly of chiral γ-cyclodextrin metal-organic framework (CDMOF), rhodamine 6G hydrazide (RGH), and tetracyanovinylindane (TCN). The embedded RGH and TCN inherit the chirality of host CDMOF, producing dual changes both in fluorescence and reflectance. RT@CDMOF is explored as a dual channel sensor for chiral discrimination of lactate enantiomers. Comprehensive mechanistic studies reveal the chiral binding process, and carboxylate dissociation is confirmed by impedance and solid-state 1 H nuclear magnetic resonance (NMR). A flexible membrane sensor is successfully fabricated based on RT@CDMOF for wearable health monitoring. Practical evaluation confirms the potential of fabricated membrane sensor in point-of-care health monitoring by indexing the exercise intensity. Based on above, a chiral IMPLICATION logic unit can be successfully achieved, demonstrating the promising potential of RT@CDMOF in design and assembly of novel smart devices. This work may open a new avenue to the rational design of logic chiral sensors for wearable health monitoring applications.