Cancer Metabolism: Current Understanding and Therapies

Novel copper complex CTB regulates methionine cycle induced TERT hypomethylation to promote HCC cells senescence via mitochondrial SLC25A26

Related research has recognized the vital role of methionine cycle metabolism in cancers. However, the role and mechanism of methionine cycle metabolism in hepatocellular carcinoma are still unknown. In this study, we found that [Cu(ttpy-tpp)Br₂]Br (Referred to as CTB) could induce hepatocellular carcinoma cells senescence, which is a new copper complex synthesized by our research group. Interestingly, CTB induces senescence by inhibiting the methionine cycle metabolism of HCC cells. Furthermore, the inhibitory effect of CTB on the methionine cycle depends on mitochondrial carrier protein SLC25A26, which was also required for CTB-induced HCC cells senescence. Importantly, we found that CTB-induced upregulation of SLC25A26 could cause abnormal methylation of TERT and inhibited TERT expression, which is considered to be an essential cause of cell senescence. The same results were also obtained in vivo, CTB inhibits the growth of subcutaneously implanted tumors in nude mice and promoted the expression of senescence markers in tumor tissues, and interference with SLC25A26 partially offset the antitumor effect of CTB.

[Fundamental aspects of oncogenesis]

Tumorigenesis has traditionally been considered as a multi-step process involving the activation of oncogenes as well as the inactivation of tumor suppressor genes. However, the mechanisms driving cancer initiation and progression are not restricted to molecular alterations and instead should be viewed as a complex process that interfaces with the entire organism. This didactic review provides an integrated and global view of the key fundamental principles of cancer development.

m6A Reader HNRNPA2B1 Promotes Esophageal Cancer Progression via Up-Regulation of ACLY and ACC1

N6-methyladenosine (m⁶A) modification is the most abundant modification on eukaryotic RNA. In recent years, lots of studies have reported that m⁶A modification and m⁶A RNA methylation regulators were involved in cancer progression. However, the m⁶A level and its regulators in esophageal cancer (ESCA) remain poorly understood. In this study, we analyzed the expression of m⁶A regulators using The Cancer Genome Atlas data and found 14 of 19 m⁶A regulators are significantly increased in ESCA samples. Then we performed a univariate Cox regression analysis and LASSO (least absolute shrinkage and selection operator) Cox regression model to investigate the prognostic role of m⁶A regulators in ESCA, and the results indicated that a two-gene prognostic signature including ALKBH5 and HNRNPA2B1 could predict overall survival of ESCA patients. Moreover, HNRNPA2B1 is higher expressed in high-risk scores subtype of ESCA, indicating that HNRNPA2B1 may be involved in ESCA development. Subsequently, we confirmed that the level of m⁶A and HNRNPA2B1 was significantly increased in ESCA. We also found that HNRNPA2B1 expression positively correlated with tumor diameter and lymphatic metastasis of ESCA. Moreover, functional study showed that knockdown of HNRNPA2B1 inhibited the proliferation, migration, and invasion of ESCA. Mechanistically, we found that knockdown of HNRNPA2B1 inhibited the expression of de novo fatty acid synthetic enzymes, ACLY and ACC1, and subsequently suppressed cellular lipid accumulation. In conclusion, our study provides critical clues to understand the role of m⁶A and its regulators in ESCA. Moreover, HNRNPA2B1 functions as an oncogenic factor in promoting ESCA progression via up-regulation of fatty acid synthesis enzymes ACLY and ACC1, and it may be a promising prognostic biomarker and therapeutic target for human ESCA.

Inhibition of Tumor Progression through the Coupling of Bacterial Respiration with Tumor Metabolism

By leveraging the ability of Shewanella oneidensis MR-1 (S. oneidensis MR-1) to anaerobically catabolize lactate through the transfer of electrons to metal minerals for respiration, a lactate-fueled biohybrid (Bac@MnO₂ ) was constructed by modifying manganese dioxide (MnO₂ ) nanoflowers on the S. oneidensis MR-1 surface. The biohybrid Bac@MnO₂ uses decorated MnO₂ nanoflowers as electron receptor and the tumor metabolite lactate as electron donor to make a complete bacterial respiration pathway at the tumor sites, which results in the continuous catabolism of intercellular lactate. Additionally, decorated MnO₂ nanoflowers can also catalyze the conversion of endogenous hydrogen peroxide (H₂ O₂ ) into generate oxygen (O₂ ), which could prevent lactate production by downregulating hypoxia-inducible factor-1α (HIF-1α) expression. As lactate plays a critical role in tumor development, the biohybrid Bac@MnO₂ could significantly inhibit tumor progression by coupling bacteria respiration with tumor metabolism.

Flavin dependency undermines proteome stability, lipid metabolism and cellular proliferation during vitamin B2 deficiency

Tumor cells adapt their metabolism to meet the energetic and anabolic requirements of high proliferation and invasiveness. The metabolic addiction has motivated the development of therapies directed at individual biochemical nodes. However, currently there are few possibilities to target multiple enzymes in tumors simultaneously. Flavin-containing enzymes, ca. 100 proteins in humans, execute key biotransformations in mammalian cells. To expose metabolic addiction, we inactivated a substantial fraction of the flavoproteome in melanoma cells by restricting the supply of the FMN and FAD precursor riboflavin, the vitamin B2. Vitamin B2 deficiency affected stability of many polypeptides and thus resembled the chaperone HSP90 inhibition, the paradigmatic multiple-target approach. In support of this analogy, flavin-depleted proteins increasingly associated with a number of proteostasis network components, as identified by the mass spectrometry analysis of the FAD-free NQO1 aggregates. Proteome-wide analysis of the riboflavin-starved cells revealed a profound inactivation of the mevalonate pathway of cholesterol synthesis, which underlines the manifold cellular vulnerability created by the flavoproteome inactivation. Cell cycle-arrested tumor cells became highly sensitive to alkylating chemotherapy. Our data suggest that the flavoproteome is well suited to design synthetic lethality protocols combining proteostasis manipulation and metabolic reprogramming.

Chemistry of Advanced Nanomedicines in Cancer Cell Metabolism Regulation

Tumors reprogram their metabolic pathways to meet the bioenergetic and biosynthetic demands of cancer cells. These reprogrammed activities are now recognized as the hallmarks of cancer, which not only provide cancer cells with unrestricted proliferative and metastatic potentials, but also strengthen their resistance against stress conditions and therapeutic challenges. Although recent progress in nanomedicine has largely promoted the developments of various therapeutic modalities, such as photodynamic therapy, photothermal therapy, nanocatalytic therapy, tumor-starving/suffocating therapy, etc., the therapeutic efficacies of nanomedicines are still not high enough to achieve satisfactory tumor-suppressing effects. Therefore, researchers are obliged to look back to the essence of cancer cell biology, such as metabolism, for tailoring a proper therapeutic regimen. In this work, the characteristic metabolic pathways of cancer cells, such as aerobic respiration, glycolysis, autophagy, glutaminolysis, etc. are reviewed, to summarize the very recent advances in the smart design of nanomedicines that can regulate tumor metabolism for enhancing conventional therapeutic modalities. The underlying chemistry of these nanomedicines by which tumor metabolism is harnessed, is also discussed in a comprehensive manner. It is expected that by harnessing tumor metabolism cancer nanotherapeutics will be substantially improved in the future.

Molecular targets and anticancer activity of quinoline-chalcone hybrids: literature review

α,β-Unsaturated chalcone moieties and quinoline scaffolds play an important role in medicinal chemistry, especially in the identification and development of potential anticancer agents. The multi-target approach or hybridization is considered as a promising strategy in drug design and discovery. Hybridization may improve the affinity and potency while simultaneously decreasing the resistance and/or side effects. The conjugation of quinolines with chalcones has been a promising approach to the identification of potential anticancer agents. Most of these hybrids showed anticancer activities through the inhibition of tubulin polymerization, different kinases, topoisomerases, or by affecting DNA cleavage activity. Accordingly, this class of compounds can be classified based on their molecular modes of action. In this article, the quinolone-chalcone hybrids with potential anticancer activity have been reviewed. This class of compounds might be helpful for the design, discovery and development of new and potential multi-target anticancer agents or drugs.

PFKFB3 inhibitors as potential anticancer agents: Mechanisms of action, current developments, and structure-activity relationships

Cancer cells adopt aerobic glycolysis as the major source of energy and biomass production for fast cell proliferation. The bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), plays a crucial role in the regulation of glycolysis by controlling the steady-state cytoplasmic levels of fructose-2,6-bisphosphate (F2,6BP), which is the most potent allosteric activator of 6-phosphofructo-1-kinase (PFK-1), a key rate-limiting enzyme of glycolysis. Therefore, selective inhibition of PFKFB3 has gained substantial interest as an attractive strategy for cancer therapy. In recent years, numerous class PFKFB3 inhibitors have been disclosed, and emerging trends such as the availability of PFKFB3 crystal structures, structure-based screening strategies and diverse functional assays are improving optimization and development of original leads. Herein, we review the structure and function of PFKFB3 as well as the representative small-molecule inhibitors, in particular emphasis on their chemical structures, pharmacological properties, selectivity, binding modes and structure-activity relationships (SARs).

Denaturant-Mediated Modulation of the Formation and Drug Encapsulation Responses of Gold Nanoparticles

The extensive and diversified applications of the well-known plasmonic nanoparticle systems along with their easy and environment-friendly synthesis strategies drive us to investigate in-depth this important research field. In the current scenario, our present study deals with an important plasmonic nanomaterial, i.e., globular protein, and human serum albumin (HSA)-conjugated gold nanoparticle (HSA-Au NP) system. The well-known chemical denaturants, urea and guanidine hydrochloride (GdnHCl or GnHCl), are investigated to show detrimental effects toward the formation of gold nanoparticles; however, the effect of GdnHCl is observed to be much prominent compared to that of urea. The synthesized nanoparticle system is found to be highly biocompatible from the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based cytotoxicity assay, and therefore, the applications of encapsulation of the well-known anticancer drug molecule, doxorubicin hydrochloride (Dox), in the nanoparticle system are further studied. In this drug encapsulation study, drug-metal complexation between Dox and HAuCl₄·3H₂O has been discussed elaborately. Similar to the nanoparticle formation, the effects of denaturants on drug encapsulation have also been discovered, and interestingly, it has been observed that urea plays a positive role, whereas GdnHCl plays a negative or detrimental role toward drug encapsulation in the synthesized gold nanoparticle system. The detailed photophysical mechanisms behind the drug encapsulation in the synthesized plasmonic nanosystem at every stage have also been explored. Overall, this study will conclusively explain the influences of the extensively used chemical denaturants on the synthesis and drug encapsulation behaviors of a well-known protein-conjugated gold nanoparticle, and as a consequence, it can be highly useful and acceptable to the biomedical and pharmaceutical research communities.

TGFβ-induced metabolic reprogramming during epithelial-to-mesenchymal transition in cancer

Metastasis is the most frequent cause of death in cancer patients. Epithelial-to-mesenchymal transition (EMT) is the process in which cells lose epithelial integrity and become motile, a critical step for cancer cell invasion, drug resistance and immune evasion. The transforming growth factor-β (TGFβ) signaling pathway is a major driver of EMT. Increasing evidence demonstrates that metabolic reprogramming is a hallmark of cancer and extensive metabolic changes are observed during EMT. The aim of this review is to summarize and interconnect recent findings that illustrate how changes in glycolysis, mitochondrial, lipid and choline metabolism coincide and functionally contribute to TGFβ-induced EMT. We describe TGFβ signaling is involved in stimulating both glycolysis and mitochondrial respiration. Interestingly, the subsequent metabolic consequences for the redox state and lipid metabolism in cancer cells are found to be in favor of EMT as well. Combined we illustrate that a better understanding of the mechanistic links between TGFβ signaling, cancer metabolism and EMT holds promising strategies for cancer therapy, some of which are already actively being explored in the clinic.

Bromodomains and Extra-Terminal (BET) Inhibitor JQ1 Suppresses Proliferation of Acute Lymphocytic Leukemia by Inhibiting c-Myc-Mediated Glycolysis

Background

Acute lymphocytic leukemia (ALL) is a common blood cancer which induces high mortality in children. Bromodomains and extra-terminal (BET) protein inhibitors, such as JQ1 and ARV-825, are promising cancer therapeutic agents that can be used by targeting c-Myc. A recent work reported that JQ1 effectively attenuates ALL in vitro by suppressing cell proliferation and accelerating apoptosis. The purpose of this research was to probe into the potential mechanism of how JQ1 inhibits ALL cell proliferation in vitro.

Material/Methods

Cell viability of ALL cells were measured by CTG after treatment by JQ1. Cell cycle analysis was done by EdU and PI staining. Cell apoptosis was assessed by Annexin V/PI staining. Glycolysis was detected using Seahorse and LC-MS kits. The expression of glycolytic rate-limiting enzymes was assessed by RNA-seq, qRT-PCR, and Western blot.

Results

JQ1 suppressed cell proliferation by arresting the cell cycle and inducing the apoptosis of acute lymphocytic leukemia cells. JQ1 inhibited cell proliferation of B-ALL cells by restraining glycolysis. Conversely, the cell cycle block of B-ALL cells induced by JQ1 was partially abolished after pretreatment with 2-Deoxy-D-glucose (2-DG), an inhibitor of glycolysis. Furthermore, JQ1 restrained the glycolysis of B-ALL cell lines by remarkably downregulating the rate-limiting enzymes of glycolysis, such as hexokinase 2, phosphofructokinase, and lactate dehydrogenase A. Moreover, the cell cycle arrest was reversed in B-ALL cells with overexpressed c-Myc treated by JQ1, which is involved in the enhancement of glycolysis.

Conclusions

The BET inhibitor JQ1 suppresses the proliferation of ALL by inhibiting c-Myc-mediated glycolysis, thus providing a new strategy for the treatment of ALL.

Modulation of dysregulated cancer metabolism by plant secondary metabolites: A mechanistic review

Several signaling pathways and basic metabolites are responsible for the control of metabolism in both normal and cancer cells. As emerging hallmarks of cancer metabolism, the abnormal activities of these pathways are of the most noticeable events in cancer. This altered metabolism expedites the survival and proliferation of cancer cells, which have attracted a substantial amount of interest in cancer metabolism. Nowadays, targeting metabolism and cross-linked signaling pathways in cancer has been a hot topic to investigate novel drugs against cancer. Despite the efficiency of conventional drugs in cancer therapy, their associated toxicity, resistance, and high-cost cause limitations in their application. Besides, considering the numerous signaling pathways cross-linked with cancer metabolism, discovery, and development of multi-targeted and safe natural compounds has been a high priority. Natural secondary metabolites have exhibited promising anticancer effects by targeting dysregulated signaling pathways linked to cancer metabolism. The present review reveals the metabolism and cross-linked dysregulated signaling pathways in cancer. The promising therapeutic targets in cancer, as well as the critical role of natural secondary metabolites for significant anticancer enhancements, have also been highlighted to find novel/potential therapeutic agents for cancer treatment.

pH-Sensitive nanotheranostics for dual-modality imaging guided nanoenzyme catalysis therapy and phototherapy

A theranostic nanosystem with a pH-sensitive structure showed charge conversion properties in the tumor acidic microenvironment. It could perform dual-modality imaging diagnosis and carry out catalysis therapy and phototherapy.

pH stimulus-disaggregated BODIPY: an activated photodynamic/photothermal sensitizer applicable to tumor ablation

A pH activated photodynamic/photothermal sensitizer applicable to tumor ablation.

Milk-exosome based pH/light sensitive drug system to enhance anticancer activity against oral squamous cell carcinoma

A multimodal drug delivery system targeting the tumor microenvironment is an inspiring method for treating cancer tissues, including oral squamous cell carcinomas (OSCC). Such approaches require an efficient and safe drug carrier. Bovine milk derived exosomes are ideal because the source is adequate and have advantages of both synthetic and cell-mediated nano carriers. In the present study, we developed a pH/light sensitive drug system based on milk-exosomes for OSCC therapy. It was called exosome–doxorubicin–anthracene endoperoxide derivative (Exo@Dox–EPT1, NPs). Milk-exosomes were conjugated to doxorubicin (Dox) by a pH-cleavable bond, which can rapture under an acidic microenvironment. Besides, endoperoxides and chlorin e6 (Ce6) were also loaded and the endoperoxides undergo thermal cycloreversion and release singlet oxygen to kill cancer cells. We have also investigated the body distribution, antitumor effects, and biocompatibility of the nanoparticles. The new milk-exosome-based drug delivery system showed controlled drug-release, biocompatibility and, proved to be effective in treating OSCC.

A multimodal drug delivery system targeting the tumor microenvironment is an inspiring method for treating cancer tissues, including oral squamous cell carcinomas (OSCC).

Immunonutrition vs Standard Nutrition for Cancer Patients: A Systematic Review and Meta-Analysis (Part 1)

The aim of this study was to determine the efficacy of immunonutrition vs standard nutrition in cancer patients treated with surgery. Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, EBSCOhost, and Web of Science were searched. Sixty-one randomized controlled trials were included. Immunonutrition was associated with a significantly reduced risk of postoperative infectious complications (risk ratio [RR] 0.71 [95% CI, 0.64-0.79]), including a reduced risk of wound infection (RR 0.72 [95% CI, 0.60-0.87]), respiratory tract infection (RR 0.70 [95% CI, 0.59-0.84]), and urinary tract infection (RR 0.69 [95% CI, 0.51-0.94]) as well as a decreased risk of anastomotic leakage (RR 0.70 [95% CI, 0.53-0.91]) and a reduced hospital stay (MD -2.12 days [95% CI -2.72 to -1.52]). No differences were found between the 2 groups with regard to sepsis or all-cause mortality. Subgroup analyses revealed that receiving arginine + nucleotides + ω-3 fatty acids and receiving enteral immunonutrition reduced the rates of wound infection and respiratory tract infection. The application of immunonutrition at 25-30 kcal/kg/d for 5-7 days reduced the rate of respiratory tract infection. Perioperative immunonutrition reduced the rate of wound infection. For malnourished patients, immunonutrition shortened the hospitalization time. Therefore, immunonutrition reduces postoperative infection complications and shortens hospital stays but does not reduce all-cause mortality. Patients who are malnourished before surgery who receive arginine + nucleotides + ω-3 fatty acids (25-30 kcal/kg/d) via the gastrointestinal tract during the perioperative period (5-7 days) may show better clinical efficacy.

Nanocatalytic Medicine

Catalysis and medicine are often considered as two independent research fields with their own respective scientific phenomena. Promoted by recent advances in nanochemistry, large numbers of nanocatalysts, such as nanozymes, photocatalysts, and electrocatalysts, have been applied in vivo to initiate catalytic reactions and modulate biological microenvironments for generating therapeutic effects. The rapid growth of research in biomedical applications of nanocatalysts has led to the concept of "nanocatalytic medicine," which is expected to promote the further advance of such a subdiscipline in nanomedicine. The high efficiency and selectivity of catalysis that chemists strived to achieve in the past century can be ingeniously translated into high efficacy and mitigated side effects in theranostics by using "nanocatalytic medicine" to steer catalytic reactions for optimized therapeutic outcomes. Here, the rationale behind the construction of nanocatalytic medicine is eludicated based on the essential reaction factors of catalytic reactions (catalysts, energy input, and reactant). Recent advances in this burgeoning field are then comprehensively presented and the mechanisms by which catalytic nanosystems are conferred with theranostic functions are discussed in detail. It is believed that such an emerging catalytic therapeutic modality will play a more important role in the field of nanomedicine.

Nanoclustered Cascaded Enzymes for Targeted Tumor Starvation and Deoxygenation-Activated Chemotherapy without Systemic Toxicity

Intratumoral glucose depletion-induced cancer starvation represents an important strategy for anticancer therapy, but it is often limited by systemic toxicity, nonspecificity, and adaptive development of parallel energy supplies. Herein, we introduce a concept of cascaded catalytic nanomedicine by combining targeted tumor starvation and deoxygenation-activated chemotherapy for an efficient cancer treatment with reduced systemic toxicity. Briefly, nanoclustered cascaded enzymes were synthesized by covalently cross-linking glucose oxidase (GOx) and catalase (CAT) via a pH-responsive polymer. The release of the enzymes can be first triggered by the mildly acidic tumor microenvironment and then be self-accelerated by the subsequent generation of gluconic acid. Once released, GOx can rapidly deplete glucose and molecular oxygen in tumor cells while the toxic side product, i.e., H₂O₂, can be readily decomposed by CAT for site-specific and low-toxicity tumor starvation. Furthermore, the enzymatic cascades also created a local hypoxia with the oxygen consumption and reductase-activated prodrugs for an additional chemotherapy. The current report represents a promising combinatorial approach using cascaded catalytic nanomedicine to reach concurrent selectivity and efficiency of cancer therapeutics.

Mild Hyperthermia-Enhanced Enzyme-Mediated Tumor Cell Chemodynamic Therapy

The heterogeneity and diversity of tumors seriously attenuate the curative outcome of single treatment modes. Combined therapy has been demonstrated to be a promising candidate to enhance therapeutic efficacy compared with monotherapy. As an emerging therapeutic strategy, chemodynamic therapy (CDT) has drawn extensive attention in recent years. However, the therapeutic efficiency of CDT is still unsatisfying because the level of intracellular hydrogen peroxide (H₂O₂) restricts the production of hydroxyl radicals (^•OH). In this study, a novel curative strategy which combines glucose oxidase (GOx)-mediated Fe₃O₄-based Fenton reaction and multiwalled carbon nanotube (MWNT)-produced mild hyperthermia enhancer is proposed, achieving a mild hyperthermia-enhanced enzyme-mediated tumor cell CDT. GOx can catalyze the conversion of glucose into gluconic acid and H₂O₂, which can elevate acidity in the tumor microenvironment and boost Fe₃O₄-based Fenton reaction, producing a myriad of ^•OH to induce tumor cell death. Furthermore, by using the theory that a temperature rise expedites the kinetics of a chemical reaction, producing a higher reaction rate and more resultants per unit time, we integrate MWNTs in this therapy system, which generate mild hyperthermia so as to accelerate the Fenton reaction for increasing the productivity of ^•OH. Therefore, an amplified CDT can be realized. The therapy platform, mild hyperthermia-enhanced GOx-mediated CDT, provides an effective treatment for cancer and takes CDT a step further.

Tetrazole hybrids with potential anticancer activity

Cancer is one of the main causes of death throughout the world. The anticancer agents are indispensable for the treatment of various cancers, but most of them currently on the market are not specific, resulting in series of side effects of chemotherapy. Moreover, the emergency of drug-resistance towards cancers has already increased up to alarming level in the recent decades. Therefore, it's imperative to develop novel anticancer candidates with excellent activity against both drug-susceptible and drug-resistant cancers, and low toxicity as well. Tetrazole is the bioisoster of carboxylic acid, and its derivatives demonstrated promising anticancer activity. Hybridization of tetrazole with other anticancer pharmacophores may provide novel candidates with anticancer potency. The present review described the anticancer activity of tetrazole hybrids, and the structure-activity relationship (SAR) is also discussed to provide an insight for rational designs of tetrazole anticancer candidates with higher efficiency.

Mapping and Profiling Lipid Distribution in a 3D Model of Breast Cancer Progression

Aberrant lipid accumulation and marked changes in cellular lipid profiles are related to breast cancer metabolism and disease progression. In vitro, these phenomena are primarily studied using cells cultured in monolayers (2D). Here, we employ multicellular spheroids, generated using the MCF10A cell line series of increasing malignancy potential, to better recapitulate the 3D microenvironmental conditions that cells experience in vivo. Breast cancer cell lipid compositions were assessed in 2D and 3D culture models as a function of malignancy using liquid chromatography coupled with mass spectrometry. Further, the spatial distribution of lipids was examined using Raman chemical imaging and lipid staining. We show that with changes in the cellular microenvironment when moving from 2D to 3D cell cultures, total lipid amounts decrease significantly, while the ratio of acylglycerols to membrane lipids increases. This ratio increase could be associated with the formation of large lipid droplets (>10 μm) that are spatially evident throughout the spheroids but absent in 2D cultures. Additionally, we found a significant difference in lipid profiles between the more and less malignant spheroids, including changes that support de novo sphingolipid production and a reduction in ether-linked lipid fractions in the invasive spheroids. These differences in lipid profiles as a function of cell malignancy and microenvironment highlight the importance of coupled spatial and lipidomic studies to better understand the connections between lipid metabolism and cancer.

Synthesis of amide and sulfonamide substituted N-aryl 6-aminoquinoxalines as PFKFB3 inhibitors with improved physicochemical properties

In oncology, the "Warburg effect" describes the elevated production of energy by glycolysis in cancer cells. The ubiquitous and hypoxia-induced 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) plays a noteworthy role in the regulation of glycolysis by producing fructose-2,6-biphosphate (F-2,6-BP), a potent activator of the glycolysis rate-limiting phosphofructokinase PFK-1. Series of amides and sulfonamides derivatives based on a N-aryl 6-aminoquinoxaline scaffold were synthesized and tested for their inhibition of PFKFB3 in vitro in a biochemical assay as well as in HCT116 cells. The carboxamide series displayed satisfactory kinetic solubility and metabolic stability, and within this class, potent lead compounds with low nanomolar activity have been identified with a suitable profile for further in vivo evaluation.

Design and synthesis of boron containing monosaccharides by the hydroboration of d-glucal for use in boron neutron capture therapy (BNCT)

Boron neutron capture therapy (BNCT) is one of the radiotherapies that involves the use of boron-containing compounds for the treatment of cancer. Boron-10 (¹⁰B) containing compounds that can accumulate in tumor tissue are expected to be suitable agents for BNCT. We report herein on the design and synthesis of some new BNCT agents based on a d-glucose scaffold, since glycoconjugation has been recognized as a useful strategy for the specific targeting of tumors. To introduce a boryl group into a d-glucose scaffold, we focused on the hydroboration of d-glucal derivatives, which have a double bond between the C1 and C2 positions. It was hypothesized that a C-B bond could be introduced at the C2 position of d-glucose by the hydroboration of d-glucal derivatives and that the products could be stabilized by conversion to the corresponding boronic acid ester. To test this hypothesis, we prepared some 2-boryl-1,2-dideoxy-d-glucose derivatives as boron carriers and evaluated their cytotoxicity and cellular uptake activity to cancer cells, especially under hypoxic conditions.

Discovery of potent pyruvate dehydrogenase kinase inhibitors and evaluation of their anti-lung cancer activity under hypoxia

Targeting pyruvate dehydrogenase kinases (PDKs) reverses the Warburg effect, which could be a potential therapeutic target for anti-cancer drug discovery. In this paper, we identified 12 potential PDK inhibitors by virtual ligand screening of a chemical library, and then further verified them by an enzymatic assay, in which 6, 7, and 11 strongly inhibited the function of PDKs, with IC₅₀ values of 1.26, 0.62, and 0.41 μM against PDK1, respectively, and showed a similar inhibitory effect on PDK2, PDK3, and PDK4. However, we failed to correlate the observed inhibitory activity against PDKs with cellular activity under normal conditions. In contrast, 7 and 11 inhibited NCI-H1975 cell proliferation under hypoxia, with EC₅₀ values of 4.66 and 3.88 μM, respectively, suggesting that 7 and 11 could be promising leads for further development of PDK inhibitors in cancer treatment.