"Golgi-customized Trojan horse" nanodiamonds impair GLUT1 plasma membrane localization and inhibit tumor glycolysis

Nutrient or energy deprivation, especially glucose restriction, is a promising anticancer therapeutic approach. However, establishing a precise and potent deprivation strategy remains a formidable task. The Golgi morphology is crucial in maintaining the function of transport proteins (such as GLUT1) driving glycolysis. Thus, in this study, we present a "Golgi-customized Trojan horse" based on tellurium loaded with apigenin (4',5,7-trihydroxyflavone) and human serum albumin, which was able to induce GLUT1 plasma membrane localization disturbance via Golgi dispersal leading to the inhibition of tumor glycolysis. Diamond-shaped delivery system can efficiently penetrate into cells as a gift like Trojan horse, which decomposes into tellurite induced by intrinsically high H2O2 and GSH levels. Consequently, tellurite acts as released warriors causing up to 3.8-fold increase in Golgi apparatus area due to the down-regulation of GOLPH3. Further, this affects GLUT1 membrane localization and glucose transport disturbance. Simultaneously, apigenin hinders ongoing glycolysis and causes significant decrease in ATP level. Collectively, our "Golgi-customized Trojan horse" demonstrates a potent antitumor activity because of its capability to deprive energy resources of cancer cells. This study not only expands the applications of tellurium-based nanomaterials in the biomedicine but also provides insights into glycolysis restriction for anticancer therapy.

Optimizing d-mannose and glyceraldehyde concentrations as glucose preservatives without clinically affecting biochemical test results

Objectives: The objectives were to evaluate blood additives that combined lithium heparin (LH)-salt with glyceraldehyde (GLY) or d-mannose (MAN) for preserving glucose levels in plasma samples and to simultaneously determine the compatibility of these additives with 14 other biochemical tests.

Methods

Blood samples from 40 subjects, equally divided into healthy and diabetic groups, were collected using five different additives. The three most effective additives, LH/GLY, LH/MAN, and LH/GLY/MAN, were selected for ensuring the best preservation of glucose levels and compatibility with 14 biochemical tests. One-way analysis of variance was used to analyze the mean paired differences of glucose level and biochemical tests. Simultaneously, the clinical criteria from Johns Hopkins Hospital were used to guide the interpretation and set acceptable thresholds for measurements that exceeded the standards.

Results

The combination of 160 mmol/L GLY, 8.4 mmol/L MAN, and LH, maintained glucose levels at approximately 93.4-93.7 % for healthy subjects and 91.3-92.8% for subjects with diabetes mellitus over 8 h. The mean paired differences of glucose levels in preservation were statistically insignificant. The biases in 14 biochemical tests for LH/GLY/MAN and LH/MAN remained within the acceptable clinical criteria during the 8 h.

Conclusions

Combining 160 mmol/L GLY, 8.4 mmol/L MAN, and LH, proved more effective in maintaining glucose levels than individual additives or the conventional sodium fluoride preservative. It did not yield clinical discrepancies in the 14 biochemical tests during 8 h at room temperature.

Hydroquinone-selected chronic myelogenous leukemia cells are sensitive to chloroquine-induced cytotoxicity via MCL1 suppression and glycolysis inhibition

Previous studies have provided evidence that repeated exposure to the benzene metabolite hydroquinone (HQ) induces malignant transformation and increases basal autophagy in the chronic myeloid leukemia (CML) cell line K562. This study explored the cytotoxicity of the autophagy inhibitor chloroquine (CQ) on parental and HQ-selected K562 (K562/HQ) cells. CQ triggered apoptosis in these cells independently of inhibiting autophagic flux; however, in K562/HQ cells, CQ-induced cytotoxicity was higher than in K562 cells. Mechanistically, CQ-induced NOXA upregulation led to MCL1 downregulation and mitochondrial depolarization in K562/HQ cells. MCL1 overexpression or NOXA silencing attenuated CQ-mediated cytotoxicity in K562/HQ cells. CQ triggered ERK inactivation to increase Sp1, NFκB, and p300 expression, and co-assembly of Sp1, NFκB, and p300 in the miR-29a promoter region coordinately upregulated miR-29a transcription. CQ-induced miR-29a expression destabilized tristetraprolin (TTP) mRNA, which in turn reduced TTP-mediated NOXA mRNA decay, thereby increasing NOXA protein expression. A similar mechanism explained the CQ-induced downregulation of MCL1 in K562 cells. K562/HQ cells relied more on glycolysis for ATP production than K562 cells, whereas inhibition of glycolysis by CQ was greater in K562/HQ cells than in K562 cells. Likewise, CQ-induced MCL1 suppression and glycolysis inhibition resulted in higher cytotoxicity in CML KU812/HQ cells than in KU812 cells. Taken together, our data confirm that CQ inhibits MCL1 expression through the ERK/miR-29a/TTP/NOXA pathway, and that inhibition of glycolysis is positively correlated to higher cytotoxicity of CQ on HQ-selected CML cells.

Bioreducible exosomes encapsulating glycolysis inhibitors potentiate mitochondria-targeted sonodynamic cancer therapy via cancer-targeted drug release and cellular energy depletion

Nanocarrier-assisted sonodynamic therapy (SDT) has shown great potential for the effective and targeted treatment of deep-seated tumors by overcoming the critical limitations of sonosensitizers. However, in vivo SDT using nanocarriers is still constrained by their intrinsic toxicity and nonspecific cargo release. In this study, we developed bioreducible exosomes for the safe and tumor-specific delivery of mitochondria-targeting sonosensitizers [triphenylphosphonium-conjugated chlorin e6 (T-Ce6)] and glycolysis inhibitors (FX11). Redox-cleavable diselenide linker-bearing lipids were embedded into exosomes to trigger drug release in response to overexpressed glutathione in the tumor microenvironment. Bioreducible exosomes facilitate the cytoplasmic release of their payload in the reducing environment of tumor cells. They significantly enhance drug release and sonodynamic effects when irradiated with ultrasound (US). The mitochondria-targeted accumulation of T-Ce6 efficiently damaged the mitochondria of the cells under US irradiation, accelerating apoptotic cell death. FX11 substantially inhibited cellular energy metabolism, potentiating the antitumor efficacy of mitochondria-targeted SDT. Bioreducible exosomes effectively suppressed tumor growth in mice without significant systemic toxicity, via a combination of mitochondria-targeted SDT and energy metabolism-targeted therapy. This study offers new insights into the use of dual stimuli-responsive exosomes encapsulating sonosensitizers for safe and targeted sonodynamic cancer therapy.

Tumor metabolism destruction via metformin-based glycolysis inhibition and glucose oxidase-mediated glucose deprivation for enhanced cancer therapy

Cancer cells rely on glycolysis to support a high proliferation rate. Metformin (Met) is a promising drug for tumor treatment that targets hexokinase 2 (HK2) to block the glycolytic process, thereby further disrupting the metabolism of cancer cells. Herein, an intelligent nanomedicine based on glucose deprivation and glycolysis inhibition is creatively constructed for enhanced cancer synergistic treatment. In brief, Met and glucose oxidase (GOx) was encapsulated into histidine/zeolitic imidazolate framework-8 (His/ZIF-8), which was followed by coating with Arg-Gly-Asp (RGD) peptides to obtain the desired nanomedicine (Met/GOx@His/ZIF-8∼RGD). This smart nanomedicine presents the controllable Met and GOx release behavior in an acidic responsive manner. The liberated Met blocks the glycolysis process via suppressing the activity of HK2 and impairing ATP production, which activates the AMP-activated protein kinase (AMPK) pathway and p53 pathway and damages the Warburg effect, eventually leading to cells apoptosis. And the GOx boosts the glucose shortage for starvation therapy by depleting accumulated glucose. According to in vitro and in vivo assays, the combination of glycolysis inhibition and starvation therapy demonstrates efficient cancer cells growth suppression and superior antitumor properties compared to the Met based or GOx-mediated monotherapy. This work provides an advanced therapeutic strategy via disrupting cellular metabolism against cancer. STATEMENT OF SIGNIFICANCE: The obtained nanomedicine (Met/GOx@His/ZIF-8∼RGD) presents the controllable Met and glucose oxidase (GOx) release behavior in an acidic responsive manner. The liberated Met blocks the glycolysis process via suppressing the activity of HK2 and impairing ATP production, which activates the AMP-activated protein kinase (AMPK) pathway and p53 pathway and damages the Warburg effect, eventually leading to cells apoptosis. And the GOx boosts the glucose shortage for starvation therapy by depleting accumulated glucose. The combination of glycolysis inhibition and starvation therapy demonstrate the efficient suppression of cancer cells growth and the superior antitumor properties when compared to the Met based or GOx-mediated monotherapy.

Three birds with one stone: co-encapsulation of diclofenac and DL-menthol for realizing enhanced energy deposition, glycolysis inhibition and anti-inflammation in HIFU surgery

Despite attracting increasing attention in clinic, non-invasive high-intensity focused ultrasound (HIFU) surgery still commonly suffers from tumor recurrence and even matastasis due to the generation of thermo-resistance in non-apoptotic tumor cells and adverse therapy-induced inflammation with enhanced secretion of growth factors in irradiated region. In this work, inspired by the intrinsic property that the expression of thermo-resistant heat shock proteins (HSPs) is highly dependent with adenosine triphosphate (ATP), dual-functionalized diclofenac (DC) with anti-inflammation and glycolysis-inhibition abilities was successfully co-encapsulated with phase-change dl-menthol (DLM) in poly(lactic-co-glycolic acid) nanoparticles (DC/DLM@PLGA NPs) to realize improved HIFU surgery without causing adverse inflammation. Both in vitro and in vivo studies demonstrated the great potential of DC/DLM@PLGA NPs for serving as an efficient synergistic agent for HIFU surgery, which can not only amplify HIFU ablation efficacy through DLM vaporization-induced energy deposition but also simultaneously sensitize tumor cells to hyperthermia by glycolysis inhibition as well as diminished inflammation. Thus, our study provides an efficient strategy for simultaneously improving the curative efficiency and diminishing the harmful inflammatory responses of clinical HIFU surgery.

3-Bromopyruvate-induced glycolysis inhibition impacts larval growth and development and carbohydrate homeostasis in fall webworm, Hyphantria cunea Drury

As a typical glycolytic inhibitor, 3-bromopyruvate (3-BrPA) has been extensively studied in cancer therapy in recent decades. However, few studies focused on 3-BrPA in regulating the growth and development of insects, and the relationship and regulatory mechanism between glycolysis and chitin biosynthesis remain largely unknown. The Hyphantria cunea, named fall webworm, is a notorious defoliator, which caused a huge economic loss to agriculture and forestry. Here, we investigated the effects of 3-BrPA on the growth and development, glycolysis, carbohydrate homeostasis, as well as chitin synthesis in H. cunea larvae. To elucidate the action mechanism of 3-BrPA on H. cunea will provide a new insight for the control of this pest. The results showed that 3-BrPA dramatically restrained the growth and development of H. cunea larvae and resulted in larval lethality. Meanwhile, we confirmed that 3-BrPA caused a significant decrease in carbohydrate, adenosine triphosphate (ATP), pyruvic acid (PA), and triglyceride (TG) levels by inhibiting glycolysis in H. cunea larvae. Further studies indicated that 3-BrPA significantly affected the activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and trehalase, as well as expressions of the genes related to glycolysis, resulting in carbohydrate homeostasis disorder. Moreover, it was found that 3-BrPA enhanced 20-hydroxyecdysone (20E) signaling by upregulating HcCYP306A1 and HcCYP314A1, two critical genes in 20E synthesis pathway, and accelerated chitin synthesis by upregulating transcriptional levels of genes in the chitin synthesis pathway in H. cunea larvae. Taken together, our findings provide a novel insight into the mechanism of glycolytic inhibitor in regulating the growth and development of insects, and lay a foundation for the potential application of glycolytic inhibitors in pest control as well.

Evaluation of the antiproliferative activity of 106 marine microbial metabolites against human lung cancer cells and potential antiproliferative mechanism of purpuride G

A total of 106 marine microbial metabolites were evaluated for their antiproliferative activity against human lung cancer cells. Results showed that 23 compounds exhibited activity in inhibiting the proliferation of A549 and H157 cells with IC₅₀ values ranging from 1.5 to 48.2 μM. Pyrrospirone F, chrysophanol, physcion, and purpuride G are the four most active compounds with IC₅₀ values of 1.5-7.3 μM. Further investigation of purpuride G (a newly discovered sesquiterpene lactone) demonstrated its potent antiproliferative activity against six different lung cancer cells of A549, H157, H460, H1299, H1703, and PC9 with IC₅₀ values of 2.1-3.3 μM. The antiproliferative activity of purpuride G against cancer cells is related to block cell cycle, induce apoptosis through regulating the apoptotic proteins Bcl-2 and Bax, and inhibit glycolysis by downregulating two key glycolytic enzymes of hexokinase 2 and pyruvate kinase M2.

Polymer-conjugated glucosamine complexed with boric acid shows tumor-selective accumulation and simultaneous inhibition of glycolysis

We synthesized unique water-soluble synthetic-polymer, styrene-maleic acid copolymer (SMA) conjugated glucosamine (SG); which formed a stable complex with boric acid (BA). This complex had a mean particle size of 15 nm by light scattering, and single peak in gel permeation chromatography. The particles were taken up by tumor cells five times faster than free BA in vitro and liberated BA at acidic tumor pH (5-7). Liberated BA inhibited glycolysis and resulted in tumor suppression in vivo. Intravenously injected SGB-complex did bind with albumin, and plasma half-life was about 8 h in mice, and accumulated to tumor tissues about 10 times more than in normal organs. IC₅₀ of SGB-complex for HeLa cells under pO₂ of 6-9% was about 20 μg/ml (free BA equivalent), 150 times more potent than free BA. Neutron irradiation of human oral cancer cells with SGB-complex resulted in 16 times greater cell-killing than that without SGB-complex. In vivo antitumor effect was evaluated after neutron irradiation only once in SCC VII tumor bearing mice and significant tumor suppression was confirmed. These results indicate that SGB-complex is a unique multifunctional anticancer agent with much more potent activity under low pO₂ conditions as in large advanced cancers.

Glycolysis inhibition and apoptosis induction in human prostate cancer cells by FV-429-mediated regulation of AR-AKT-HK2 signaling network

Prostate cancer (PCa) depends on androgen receptor (AR) signaling to regulate cell metabolism, including glycolysis, and thereby promotes tumor growth. Glycolysis is overactive in PCa and associated with poor prognosis, but the therapeutic efficacy of glycolysis inhibitors has thus far been limited by their inability to induce cell death. FV-429, a flavonoid derivative of Wogonin, is a glycolysis inhibitor that has shown anti-cancer promise. In this study, we used FV-429 as an anti-PCa agent and investigated its mechanisms of action. In vitro, both the glycolytic ability and the viability of PCa cells were inhibited by FV-429. We found that FV-429 could induce mitochondrial dysfunction and apoptosis, with AKT-HK2 signaling pathway playing a key role. In addition, FV-429 had a pro-apoptotic effect on human prostate cancer cells that relied on the inhibition of AR expression and activity. In vivo, FV-429 exerted significant tumor-repressing activity with high safety in the xenograft model using LNCaP cells. In summary, we demonstrated that FV-429 induced glycolysis inhibition and apoptosis in human prostate cancer cells by downregulating the AR-AKT-HK2 signaling network, making FV-429 a promising candidate as one therapeutic agent for advanced PCa.

Acidosis-induced metabolic reprogramming in tumor cells enhances the anti-proliferative activity of the PDK inhibitor dichloroacetate

Altered metabolic pathways in cancer such as exacerbated glycolytic flux and increased glutamine metabolism are promising targets for anti-cancer therapies. While commonly observed in glycolytic tumors, extracellular acidosis has never been considered as a potential modulator of anti-metabolic drug activity such as dichloroacetate (DCA). Using cancer cells from various origins selected for their ability to proliferate under acidic conditions, we found that DCA exerts greater inhibitory effects on the growth of these acid-adapted cells than in parental cells. Moreover, daily DCA administration to mice led to a significant decrease in tumor growth from acid-adapted cells but not from parental cells. 13C-tracer studies revealed that DCA induced a double metabolic shift, diminishing glycolysis and increasing intracellular glutamine in acid-adapted cells. As a consequence, DCA reduced the pentose phosphate pathway activity more extensively and increased apoptosis in acid-adapted cells. Finally, the combination of DCA with a glutaminase inhibitor significantly enhanced the cytotoxic effects of DCA. Overall, the interplay between acidosis and DCA exposure leads to metabolic reprogramming that considerably alters cellular fitness.

Which sample tube should be used for routine glucose determination?

BACKGROUND

Glucose is one of the most frequently requested analytes in clinical laboratory. Blood glucose analysis is affected from in vitro glycolysis. In order to determine the most suitable blood collection tube for this purpose we have compared different tubes: sodium fluoride, lithium heparin, sodium fluoride/citrate buffer containing tubes and serum with clot activator tube for the measurement of glucose when the tube has been kept at room temperature (RT) for up to 4h.

METHODS

Venous blood was collected from 49 healthy volunteers into Sarstedt S-Monovettes for glucose analysis. Reference plasma glucose was determined in a lithium heparin tube and immediately placed in an ice/water slurry. Within 10min it was centrifuged at 4°C and plasma was separated from the blood cells. Samples have been preserved at RT for 1, 2 and 4h after drawing. Glucose has been determined using a hexokinase method.

RESULTS

Glucose levels tested in a serum with clot activator tube, in lithium heparin and in sodium fluoride/sodium EDTA tubes when compared with lithium-heparin reference plasma did not meet the desirable bias for glucose (±1.8%) when kept at RT for up to 4h. GlucoEXACT tubes, when corrected by the Sarsted recommended factor of 1.16, showed a mean (95% CI) bias of +0.96% (0.45-1.47) at 1h, +1.40% (0.88-1.93) at 2h and +0.95% (0.44-1.46) at 4h, reaching the analytical goal for the desirable bias.

CONCLUSIONS

Samples collected into GlucoEXACT tubes containing sodium fluoride/citrate buffer liquid mixture are equivalent to those collected in reference plasma tubes avoiding glycolysis completely and within a 4h delay in plasma separation.

Glycolysis inhibition and its effect in doxorubicin resistance in neuroblastoma

BACKGROUND/PURPOSE

A common trait among cancers is the increased level of glycolysis despite adequate oxygen levels to support aerobic respiration. This has been shown repeatedly in different human malignancies. Glycolysis inhibitors, especially 3-bromopyruvate, have been shown to be effective chemotherapeutic agents. The effect of glycolysis inhibition upon chemotherapy resistance is relatively unknown.

METHODS

Wild-type and doxorubicin-resistant lines of neuroblastoma (SK-N-SH and SK-N-Be(2)C) were used in this study. Using an MTT assay, the IC50 of 3-BrPA was determined. Subsequently, doxorubicin-resistant cell lines were treated with 3-bromopyruvate, doxorubicin, and 3-bromopyruvate with doxorubicin. Additionally, a luminescence ATP detection assay was used to measure intracellular ATP levels, and a lactate assay was used to determine intracellular lactate levels. All experiments were repeated in hypoxic conditions.

RESULTS

Treatment with 3-bromopyruvate and doxorubicin significantly decreased the mean cell viabilities at 24, 48, and 72hours in normoxic conditions. A similar response was replicated in hypoxic conditions. Treatment with 3-bromopyruvate significantly decreased intracellular ATP and lactate levels.

CONCLUSION

Glycolysis inhibitors such as 3-bromopyruvate could prove to become an effective means by which chemotherapy resistance can be overcome in human neuroblastoma.