Quantitative proteomics identification of phosphoglycerate mutase 1 as a novel therapeutic target in hepatocellular carcinoma

Thermal proteome profiling reveals fructose-1,6-bisphosphate as a phosphate donor to activate phosphoglycerate mutase 1

Deep understanding of sugar metabolite-protein interactions should provide implications on sugar metabolic reprogramming in human physiopathology. Although tremendous efforts have been made for determining individual event, global profiling of such interactome remains challenging. Here we describe thermal proteome profiling of glycolytic metabolite fructose-1,6-bisphosphate (FBP)-interacting proteins. Our results reveal a chemical signaling role of FBP which acts as a phosphate donor to activate phosphoglycerate mutase 1 (PGAM1) and contribute an intrapathway feedback for glycolysis and cell proliferation. At molecular level, FBP donates either C1-O-phosphate or C6-O-phosphate to the catalytic histidine of PGAM1 to form 3-phosphate histidine (3-pHis) modification. Importantly, structure-activity relationship studies facilitate the discovery of PGAM1 orthostatic inhibitors which can potentially restrain cancer cell proliferation. Collectively we have profiled a spectrum of FBP interactome, and discovered a unique covalent signaling function of FBP that supports Warburg effect via histidine phosphorylation which inspires the development of pharmacological tools targeting sugar metabolism.

CircRNA PGAM1 Promotes the Migration and Invasion of Pancreatic Adenocarcinoma Cells by Activating the AKT/mTOR Signaling Pathway

Pancreatic adenocarcinoma (PAAD) is a lethal malignancy of the gastrointestinal tract. Circular RNA, an endogenous noncoding RNA, is considered a new regulatory molecule in tumorigenesis and development. Here, we aimed to investigate the role of circPGAM1 in PAAD. The PAAD cell line HPAC was transfected with OE-circPGAM1 to overexpress circPGAM1 and treated with AZD5363 to inhibit the AKT/mTOR pathway. Simultaneously, another PAAD cell line BxPC-3 was transfected with sh-circPGAM1 to silence circPGAM1. The GEPIA database was used to determine the expression of circPGAM1 in PAAD and its association with overall and disease-free survival. CircPGAM1 expression levels were determined in cell lines using reverse transcription-quantitative PCR. The cell counting kit-8, wound healing, and transwell assays were performed to determine cell migration and invasion. The protein expression levels of phosphorylated AKT and mTOR were determined using western blotting. CircPGAM1 was overexpressed in PAAD and related to poor prognosis. Silencing circPGAM1 inhibited migration and invasion of BxPC-3 cells, and overexpression of circPGAM1 showed the opposite effects. Overall, circPGAM1 promoted the migration and invasion of PAAD cells through the AKT/mTOR axis.

Phosphoglycerate mutase 1 promotes breast cancer progression through inducing immunosuppressive M2 macrophages

Immunosuppressive tumor microenvironment (TME) contributes to tumor progression and causes major obstacles for cancer therapy. Phosphoglycerate mutase 1 (PGAM1) is a key enzyme involved in cancer metabolism while its role in remodeling TME remains unclear. In this study, we reported that PGAM1 suppression in breast cancer (BC) cells led to a decrease in M2 polarization, migration, and interleukin-10 (IL-10) production of macrophages. PGAM1 regulation on CCL2 expression was essential to macrophage recruitment, which further mediated by activating JAK-STAT pathway. Additionally, the CCL2/CCR2 axis was observed to participate in PGAM1-mediated immunosuppression via regulating PD-1 expression in macrophages. Combined targeting of PGAM1 and the CCL2/CCR2 axis led to a reduction in tumor growth in vivo. Furthermore, clinical validation in BC tissues indicated a positive correlation between PGAM1, CCL2 and macrophage infiltration. Our study provides novel insights into the induction of immunosuppressive TME by PGAM1 and propose a new strategy for combination therapies targeting PGAM1 and macrophages in BC.

Ethanolic extract from Sophora moorcroftiana inhibit cell proliferation and alter the mechanical properties of human cervical cancer

BACKGROUND

Cervical cancer is one of the most common gynecological malignancies. Previous studies have shown that the ethanol extract of Sophora moorcroftiana seeds (EESMS) possesses an antiproliferative effect on several tumors in vitro. Therefore, in this study, we assessed the impact of EESMS on human cervical carcinoma (HeLa) cell proliferation.

METHODS

The proliferation and apoptotic effects of HeLa cells treated with EESMS were evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay, dual acridine orange/ethidium bromide double staining, flow cytometry, and western blotting. Single-cell level atomic force microscopy (AFM) was conducted to detect the mechanical properties of HeLa cells, and proteomics and bioinformatics methods were used to elucidate the molecular mechanisms of EESMS.

RESULTS

EESMS treatment inhibited HeLa cell proliferation by blocking the G0/G1 phase, increasing the expression of Caspase-3 and affecting its mechanical properties, and the EESMS indicated no significant inhibitory effect on mouse fibroblasts L929 cell line. In total, 218 differentially expressed proteins were identified using two-dimensional electrophoresis, and eight differentially expressed proteins were successfully identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The differentially expressed proteins were involved in various cellular and biological processes.

CONCLUSION

This study provides a perspective on how cells change through biomechanics and a further theoretical foundation for the future application of Sophora moorcroftiana as a novel low-toxicity chemotherapy medication for treating human cervical cancer.

Energy stress-induced circDDX21 promotes glycolysis and facilitates hepatocellular carcinogenesis

Cancer cells undergo metabolic reprogramming in response to hostile microenvironments, such as energy stress; however, the underlying mechanisms remain largely unclear. It is also unknown whether energy stress-responsive circular RNA (circRNA) is involved in the regulation of glucose metabolism. Here we report that circDDX21 is upregulated in response to glucose deprivation by the transcription factor c-Myc. Functionally, circDDX21 is shown to promote glycolysis by increasing PGAM1 expression. Mechanistically, circDDX21 interacts with the RNA binding protein PABPC1, disrupting its association with the ubiquitin E3 ligase MKRN3. This disassociation attenuates MKRN3-mediated PABPC1 ubiquitination and enhances the binding of PABPC1 to PGAM1 mRNA, thereby leading to PGAM1 mRNA stabilization. The ability of the circDDX21-PGAM1 axis to promote hepatocellular carcinogenesis is validated in a xenograft mouse model. Additionally, in clinical hepatocellular carcinoma tissues, there is a positive correlation between circDDX21 and PGAM1 expression. These findings establish circDDX21 as an important regulator of glycolysis and suggest circDDX21 as a potential therapeutic target for hepatocellular carcinoma.

Targeting the Warburg effect: A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival, with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation, even under sufficient oxygen supply condition. This metabolic alteration, known as the Warburg effect, serves as a significant indicator of malignant tumor transformation. The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells. Key enzymes involved in this process include glucose transporters (GLUTs), HKs, PFKs, LDHs, and PKM2. Moreover, the expression of transcriptional regulatory factors and proteins, such as FOXM1, p53, NF-κB, HIF1α, and c-Myc, can also influence cancer progression. Furthermore, lncRNAs, miRNAs, and circular RNAs play a vital role in directly regulating the Warburg effect. Additionally, gene mutations, tumor microenvironment remodeling, and immune system interactions are closely associated with the Warburg effect. Notably, the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment. This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

Targeting metabolic reprogramming in hepatocellular carcinoma to overcome therapeutic resistance: A comprehensive review

Hepatocellular carcinoma (HCC) poses a heavy burden on human health with high morbidity and mortality rates. Systematic therapy is crucial for advanced and mid-term HCC, but faces a significant challenge from therapeutic resistance, weakening drug effectiveness. Metabolic reprogramming has gained attention as a key contributor to therapeutic resistance. Cells change their metabolism to meet energy demands, adapt to growth needs, or resist environmental pressures. Understanding key enzyme expression patterns and metabolic pathway interactions is vital to comprehend HCC occurrence, development, and treatment resistance. Exploring metabolic enzyme reprogramming and pathways is essential to identify breakthrough points for HCC treatment. Targeting metabolic enzymes with inhibitors is key to addressing these points. Inhibitors, combined with systemic therapeutic drugs, can alleviate resistance, prolong overall survival for advanced HCC, and offer mid-term HCC patients a chance for radical resection. Advances in metabolic research methods, from genomics to metabolomics and cells to organoids, help build the HCC metabolic reprogramming network. Recent progress in biomaterials and nanotechnology impacts drug targeting and effectiveness, providing new solutions for systemic therapeutic drug resistance. This review focuses on metabolic enzyme changes, pathway interactions, enzyme inhibitors, research methods, and drug delivery targeting metabolic reprogramming, offering valuable references for metabolic approaches to HCC treatment.

RFX6 facilitates aerobic glycolysis-mediated growth and metastasis of hepatocellular carcinoma through targeting PGAM1

BACKGROUND

Hepatocellular carcinoma (HCC) cells undergo reprogramming of glucose metabolism to support uncontrolled proliferation, of which the intrinsic mechanism still merits further investigation. Although regulatory factor X6 (RFX6) is aberrantly expressed in different cancers, its precise role in cancer development remains ambiguous.

METHODS

Microarrays of HCC tissues were employed to investigate the expression of RFX6 in tumour and adjacent non-neoplastic tissues. Functional assays were employed to explore the role of RFX6 in HCC development. Chromatin immunoprecipitation, untargeted metabolome profiling and sequencing were performed to identify potential downstream genes and pathways regulated by RFX6. Metabolic assays were employed to investigate the effect of RFX6 on glycolysis in HCC cells. Bioinformatics databases were used to validate the above findings.

RESULTS

HCC tissues exhibited elevated expression of RFX6. High RFX6 expression represented as an independent hazard factor correlated to poor prognosis in patients with HCC. RFX6 deficiency inhibited HCC development in vitro and in vivo, while its overexpression exerted opposite functions. Mechanistically, RFX6 bound to the promoter area of phosphoglycerate mutase 1 (PGAM1) and upregulated its expression. The increased PGAM1 protein levels enhanced glycolysis and further promoted the development of HCC.

CONCLUSIONS

RFX6 acted as a novel driver for HCC development by promoting aerobic glycolysis, disclosing the potential of the RFX6-PGAM1 axis for therapeutic targeting.

Targeting the Metabolic Enzyme PGAM2 Overcomes Enzalutamide Resistance in Castration-Resistant Prostate Cancer by Inhibiting BCL2 Signaling

The next-generation androgen receptor (AR) inhibitor enzalutamide is the mainstay treatment for metastatic prostate cancer. Unfortunately, resistance occurs rapidly in most patients, and once resistance occurs, treatment options are limited. Therefore, there is an urgent need to identify effective targets to overcome enzalutamide resistance. Here, using a genome-wide CRISPR-Cas9 library screen, we found that targeting a glycolytic enzyme, phosphoglycerate mutase PGAM2, significantly enhanced the sensitivity of enzalutamide-resistant prostate cancer cells to enzalutamide both in vivo and in vitro. Inhibition of PGAM2 together with enzalutamide treatment triggered apoptosis by decreasing levels of the antiapoptotic protein BCL-xL and increasing activity of the proapoptotic protein BAD. Mechanistically, PGAM2 bound to 14-3-3ζ and promoted its interaction with phosphorylated BAD, resulting in activation of BCL-xL and subsequent resistance to enzalutamide-induced apoptosis. In addition, high PGAM2 expression, which is transcriptionally regulated by AR, was associated with shorter survival and rapid development of enzalutamide resistance in patients with prostate cancer. Together, these findings provide evidence of a nonmetabolic function of PGAM2 in promoting enzalutamide resistance and identify PGAM2 inhibition as a promising therapeutic strategy for enzalutamide-resistant prostate cancer.

SIGNIFICANCE

PGAM2 promotes resistance to enzalutamide by activating antiapoptotic BCL-xL and suppressing apoptosis, indicating that PGAM2 is a potential target for overcoming enzalutamide resistance in prostate cancer.

Single-cell landscape and spatial transcriptomic analysis reveals macrophage infiltration and glycolytic metabolism in kidney renal clear cell carcinoma

The present study investigates the clinical relevance of glycolytic factors, specifically PGAM1, in the tumor microenvironment of kidney renal clear cell carcinoma (KIRC). Despite the established role of glycolytic metabolism in cancer pathophysiology, the prognostic implications and key targets in KIRC remain elusive. We analyzed GEO and TCGA datasets to identify DEGs in KIRC and studied their relationship with immune gene expression, survival, tumor stage, gene mutations, and infiltrating immune cells. We explored Pgam1 gene expression in different kidney regions using spatial transcriptomics after mouse kidney injury analysis. Single-cell RNA-sequencing was used to assess the association of PGAM1 with immune cells. Findings were validated with tumor specimens from 60 KIRC patients, correlating PGAM1 expression with clinicopathological features and prognosis using bioinformatics and immunohistochemistry. We demonstrated the expression of central gene regulators in renal cancer in relation to genetic variants, deletions, and tumor microenvironment. Mutations in these hub genes were positively associated with distinct immune cells in six different immune datasets and played a crucial role in immune cell infiltration in KIRC. Single-cell RNA-sequencing revealed that elevated PGAM1 was associated with immune cell infiltration, specifically macrophages. Furthermore, pharmacogenomic analysis of renal cancer cell lines indicated that inactivation of PGAM1 was associated with increased sensitivity to specific small-molecule drugs. Altered PGAM1 in KIRC is associated with disease progression and immune microenvironment. It has diagnostic and prognostic implications, indicating its potential in precision medicine and drug screening.

PGAM1 Inhibition Promotes HCC Ferroptosis and Synergizes with Anti-PD-1 Immunotherapy

The combination of immunotherapy and molecular targeted therapy exhibits promising therapeutic efficacy in hepatocellular carcinoma (HCC), but the underlying mechanism is still unclear. Here, phosphoglycerate mutase 1 (PGAM1) is identified as a novel immunometabolic target by using a bioinformatic algorithm based on multiple HCC datasets. PGAM1 is highly expressed in HCC and associated with a poor prognosis and a poor response to immunotherapy. In vitro and in vivo experiments indicate that targeting PGAM1 inhibited HCC cell growth and promoted the infiltration of CD8+ T-cells due to decreased enzymatic activity. Mechanistically, inhibition of PGAM1 promotes HCC cell ferroptosis by downregulating Lipocalin (LCN2) by inducing energy stress and ROS-dependent AKT inhibition, which can also downregulate Programmed death 1-ligand 1 (PD-L1). Moreover, an allosteric PGAM1 inhibitor (KH3) exhibits good antitumor effects in patient-derived xenograft (PDX) models and enhanced the efficacy of anti-PD-1 immunotherapy in subcutaneous and orthotopic HCC models. Taken together, the findings demonstrate that PGAM1 inhibition exerts an antitumor effect by promoting ferroptosis and CD8+ T-cell infiltration and can synergize with anti-PD-1 immunotherapy in HCC. Targeting PGAM1 can be a promising new strategy of "killing two birds with one stone" for HCC treatment.

MicroRNA-324-3p inhibits osteosarcoma progression by suppressing PGAM1-mediated aerobic glycolysis

Osteosarcoma (OS) is the most common primary malignant neoplasm of the bone. Recent studies have indicated that the inhibitory effects of microRNA (miR)-324-3p could affect the development of numerous cancers. However, its biological roles and underlying mechanisms in OS progression remain unexplored. In this study, miR-324-3p expression was markedly reduced in OS cell lines and tissues. Functionally, miR-324-3p overexpression suppressed OS progression and was involved in the Warburg effect. Mechanistically, miR-324-3p negatively regulated phosphoglycerate mutase 1 (PGAM1) expression by targeting its 3'-UTR. Moreover, high expression of PGAM1 promoted OS progression and aerobic glycolysis, which were associated with inferior overall survival in patients with OS. Notably, the tumor suppressor functions of miR-324-3p were partially recovered by PGAM1 overexpression. In summary, the miR-324-3p/PGAM1 axis plays an important role in regulating OS progression by controlling the Warburg effect. Our results provide mechanistic insights into the function of miR-324-3p in glucose metabolism and subsequently on the progression of OS. Targeting the miR-324-3p/PGAM1 axis could be a promising molecular strategy for the treatment of OS.

Targeting Glucose Metabolism Enzymes in Cancer Treatment: Current and Emerging Strategies

Simple Summary

Reprogramming of glucose metabolism is a hallmark of cancer and can be targeted by therapeutic agents. Some metabolism regulators, such as ivosidenib and enasidenib, have been approved for cancer treatment. Currently, more advanced and effective glucose metabolism enzyme-targeted anticancer drugs have been developed. Furthermore, some natural products have shown efficacy in killing tumor cells by regulating glucose metabolism, offering novel therapeutic opportunities in cancer. However, most of them have failed to be translated into clinical applications due to low selectivity, high toxicity, and side effects. Recent studies suggest that combining glucose metabolism modulators with chemotherapeutic drugs, immunotherapeutic drugs, and other conventional anticancer drugs may be a future direction for cancer treatment.

Abstract

Reprogramming of glucose metabolism provides sufficient energy and raw materials for the proliferation, metastasis, and immune escape of cancer cells, which is enabled by glucose metabolism-related enzymes that are abundantly expressed in a broad range of cancers. Therefore, targeting glucose metabolism enzymes has emerged as a promising strategy for anticancer drug development. Although several glucose metabolism modulators have been approved for cancer treatment in recent years, some limitations exist, such as a short half-life, poor solubility, and numerous adverse effects. With the rapid development of medicinal chemicals, more advanced and effective glucose metabolism enzyme-targeted anticancer drugs have been developed. Additionally, several studies have found that some natural products can suppress cancer progression by regulating glucose metabolism enzymes. In this review, we summarize the mechanisms underlying the reprogramming of glucose metabolism and present enzymes that could serve as therapeutic targets. In addition, we systematically review the existing drugs targeting glucose metabolism enzymes, including small-molecule modulators and natural products. Finally, the opportunities and challenges for glucose metabolism enzyme-targeted anticancer drugs are also discussed. In conclusion, combining glucose metabolism modulators with conventional anticancer drugs may be a promising cancer treatment strategy.

The tetrameric structure of Plasmodium falciparum phosphoglycerate mutase is critical for optimal enzymatic activity

The glycolytic enzyme phosphoglycerate mutase (PGM) is of utmost importance for overall cellular metabolism and has emerged as a novel therapeutic target in cancer cells. This enzyme is also conserved in the rapidly proliferating malarial parasite Plasmodium falciparum, which have a similar metabolic framework as cancer cells and rely on glycolysis as the sole energy-yielding process during intraerythrocytic development. There is no redundancy among the annotated PGM enzymes in Plasmodium, and PfPGM1 is absolutely required for the parasite survival as evidenced by conditional knockdown in our study. A detailed comparison of PfPGM1 with its counterparts followed by in-depth structure-function analysis revealed unique attributes of this parasitic protein. Here, we report for the first time the importance of oligomerization for the optimal functioning of the enzyme in vivo, as earlier studies in eukaryotes only focused on the effects in vitro. We show that single point mutation of the amino acid residue W68 led to complete loss of tetramerization and diminished catalytic activity in vitro. Additionally, ectopic expression of the WT PfPGM1 protein enhanced parasite growth, whereas the monomeric form of PfPGM1 failed to provide growth advantage. Furthermore, mutation of the evolutionarily conserved residue K100 led to a drastic reduction in enzymatic activity. The indispensable nature of this parasite enzyme highlights the potential of PfPGM1 as a therapeutic target against malaria, and targeting the interfacial residues critical for oligomerization can serve as a focal point for promising drug development strategies that may not be restricted to malaria only.

Evaluation of nuclear PGAM2 value in hepatocellular carcinoma prognosis

Phosphoglycerate mutase (PGAM) is a critical enzyme in glycolysis. PGAM2 is abundant in several types of tissues and malignant tumours. However, there is limited information regarding their clinicopathological significance in dysplastic nodules and hepatocellular carcinoma (HCC). This study aims to investigate the prognostic value of PGAM2 as a new biomarker for HCC. The PGAM2 expression level was evaluated by immunohistochemistry in liver cirrhosis (n = 10), low-grade dysplastic nodules (n = 15), high-grade dysplastic nodules (n = 15) and HCCs (n = 20) and 178 pairs of HCC and adjacent peritumoral liver tissues. We selected X-tile software for counting cut-point based on the outcomes for prognosis analysis, and used Kaplan-Meier analysis and Cox regression analysis can assess the prognosis of clinicopathologic parameters. Nuclear PGAM2 was significantly overexpressed in peritumoral liver tissues compared with HCC tissues (P = 0.0010). Kaplan-Meier analyses of 178 HCC samples revealed that nuclear PGAM2's high expression level, but not cytoplasmic PGAM2, was significantly related to good overall survival rate (OS). In addition, univariate and multivariate Cox analyses indicated nuclear PGAM2 expression could be regarded as valuable predictors for OS in HCC. PGAM2 was highly expressed in HCC tissues than liver cirrhosis tissues, and nuclear PGAM2's high expression might demonstrate HCC patients have poor postoperative results. Thus, nuclear PGAM2 can be regarded as valuable predictors for OS in HCC patients after surgery.

Metabolic shift to serine biosynthesis through 3-PG accumulation and PHGDH induction promotes tumor growth in pancreatic cancer

Cancer cells craftily adapt their energy metabolism to their microenvironment. Nutrient deprivation due to hypovascularity and fibrosis is a major characteristic of pancreatic ductal adenocarcinoma (PDAC); thus, PDAC cells must produce energy intrinsically. However, the enhancement of energy production via activating Kras mutations is insufficient to explain the metabolic rewiring of PDAC cells. Here, we investigated the molecular mechanism underlying the metabolic shift in PDAC cells under serine starvation. Amino acid analysis revealed that the concentrations of all essential amino acids and most nonessential amino acids were decreased in the blood of PDAC patients. In addition, the plasma serine concentration was significantly higher in PDAC patients with PHGDH-high tumors than in those with PHGDH-low tumors. Although the growth and tumorigenesis of PK-59 cells with PHGDH promoter hypermethylation were significantly decreased by serine starvation, these activities were maintained in PDAC cell lines with PHGDH promoter hypomethylation by serine biosynthesis through PHGDH induction. In fact, DNA methylation analysis by pyrosequencing revealed that the methylation status of the PHGDH promoter was inversely correlated with the PHGDH expression level in human PDAC tissues. In addition to PHGDH induction by serine starvation, PDAC cells showed enhanced serine biosynthesis under serine starvation through 3-PG accumulation via PGAM1 knockdown, resulting in enhanced PDAC cell growth and tumor growth. However, PHGDH knockdown efficiently suppressed PDAC cell growth and tumor growth under serine starvation. These findings provide evidence that targeting the serine biosynthesis pathway by inhibiting PHGDH is a potent therapeutic approach to eliminate PDAC cells in nutrient-deprived microenvironments.

Tumor microenvironment-activated cancer cell membrane-liposome hybrid nanoparticle-mediated synergistic metabolic therapy and chemotherapy for non-small cell lung cancer

BACKGROUND

Biomimetic nanotechnology-based RNA interference (RNAi) has been successful in improving theranostic efficacy in malignant tumors. Its integration with hybrid biomimetic membranes made of natural cell membranes fused with liposomal membranes is mutually beneficial and extends their biofunctions. However, limited research has focused on engineering such biomimetics to endow them with unique properties and functions, in particular, those essential for a "smart" drug delivery system, such as a tumor microenvironment (TME)-activated multifunctional biomimetic nanoplatform.

RESULTS

Herein, we utilized an integrated hybrid nanovesicle composed of cancer cell membranes (Cm) and matrix metallopeptidase 9 (MMP-9)-switchable peptide-based charge-reversal liposome membranes (Lipm) to coat lipoic acid-modified polypeptides (LC) co-loaded with phosphoglycerate mutase 1 (PGAM1) siRNA (siPGAM1) and DTX. The nanovesicle presented a negatively charged coating (citraconic anhydride-grafted poly-L-lysine, PC) in the middle layer for pH-triggered charge conversion functionalization. The established chemotherapeutic drug (DTX) co-delivery system CLip-PC@CO-LC nanoparticles (NPs) have a particle size of ~ 193 nm and present the same surface proteins as the Cm. Confocal microscopy and flow cytometry results indicated a greater uptake of MMP-9-treated CLip-PC@CO-LC NPs compared with that of the CLip-PC@CO-LC NPs without MMP-9 pretreatment. The exposure to MMP-9 activated positively charged cell-penetrating peptides on the surface of the hybrid nanovesicles. Moreover, pH triggered membrane disruption, and redox triggered DTX and siRNA release, leading to highly potent target-gene silencing in glycolysis and chemotherapy with enhanced antiproliferation ability. The biodistribution results demonstrated that the CLip-PC@LC-DiR NPs accumulated in the tumor owing to a combination of long blood retention time, homologous targeting ability, and TME-activated characteristics. The CLip-PC@CO-LC NPs led to more effective tumor growth inhibition than the DTX and free siPGAM1 formulations.

CONCLUSIONS

TME-activated cancer cell membrane-liposome integrated hybrid NPs provide an encouraging nanoplatform that combines RNAi with chemotherapy for precise treatment of non-small cell lung cancer.

A Schistosoma japonicum MicroRNA Exerts Antitumor Effects Through Inhibition of Both Cell Migration and Angiogenesis by Targeting PGAM1

MicroRNA (miRNA) is an important regulator for gene expression. Recent studies showed that some heterogenous miRNAs derived from both parasite and plant can regulate expression of mammalian gene in a cross-species or even a cross-kingdom manner. Here, we identified a Schistosoma japonicum miRNA (designated as sja-miR-61) that is present in the hepatocyte of mice infected with the parasite. The sja-miR-61 mimics significantly inhibited the migration of both mouse and human hepatoma cells in vitro. In a xenograft animal model, significant reductions of the tumor volume and weight were observed in mice inoculated with hepatoma cells transfected with sja-miR-61 mimics compared to the controls. We found that the in vivo inhibition of tumor growth was through its anti-angiogenesis activity. Mechanically, we identified the phosphoglycerate mutase 1 (PGAM1) gene as a target of sja-miR-61 and found that the sja-miR-61-mediated suppression of cell migration and anti-angiogenesis by cross-species down-regulation of PGAM1 expression. These data indicated that sja-miR-61 is a tumor suppressor miRNA that may have therapeutic potential for human cancers.

In Silico Drug Screening Analysis against the Overexpression of PGAM1 Gene in Different Cancer Treatments

Phosphoglycerate mutase 1 (PGAM1) is considered as a novel target for multiple types of cancer drugs for the upregulation in tumor, cell prefoliation, and cell migration. During aerobic glycolysis, PGAM1 plays a critical role in cancer cell metabolism by catalyzing the conversion of 3-phosphoglycerate (3PG) to 2-phosphoglycerate (2PG). In this computational-based study, the molecular docking approach was used with the best binding active sites of PGAM1 to screen 5,000 Chinese medicinal phytochemical library. The docking results were three ligands with docking score, RMSD-refine, and residues. Docking scores were -16.57, -15.22, and -15.74. RMSD values were 0.87, 2.40, and 0.98, and binding site residues were Arg 191, Arg 191, Arg 116, Arg 90, Arg 10, and Tyr 92. The best compounds were subjected to ADMETsar, ProTox-2 server, and Molinspiration analysis to evaluate the toxicological and drug likeliness potential of such selected compounds. The UCSF-Chimera tool was used to visualize the results, which shows that the three medicinal compounds named N-Nitrosohexamethyleneimine, Subtrifloralactone-K, and Kanzonol-N in chain-A were successfully binding with the active pockets of PGAM1. The study might facilitate identifying the hit molecules that could be beneficial in the development of antidrugs against various types of cancer treatment. These hit phytochemicals could be beneficial for further investigation of a novel target for cancer.

PGAM1 and TP53 mRNA levels in canine mammary carcinomas - Short communication

TP53 and PGAM1 genes play a key role in glycolysis which is an essential metabolic pathway of cancer cells for obtaining energy. The purpose of this work was to evaluate PGAM1 and TP53 mRNA expressions in canine mammary carcinomas (CMC) and to correlate them with animal data and tumour histological features. None of the nine samples analysed revealed PGAM1 DNA sequence variations. PGAM1 and TP53 RNA expressions from 21 CMC were analysed using a one-step reverse transcription-PCR kit and its platform system. Most CMC samples had low levels of PGAM1 mRNA (71.5%) and normal expression of TP53 mRNA (95.2%). Our results suggest a different feature of the Warburg effect on canine mammary cancer cells compared to human cells.

Design, synthesis, and biological evaluation of 1,3,6,7-tetrahydroxyxanthone derivatives as phosphoglycerate mutase 1 inhibitors

Phosphoglycerate mutase 1 (PGAM1) is a promising target for cancer treatment. Herein, we found that α-mangostin and γ-mangostin exhibited moderate PGAM1 inhibitory activities, with IC₅₀ of 7.2 μM and 1.2 µM, respectively. Based on α-mangostin, a series of 1,3,6,7-tetrahydroxyxanthone derivatives were designed, synthesized and evaluated in vitro for PGAM1 inhibition. The significant structure-activity relationships (SAR) and a fresh binding mode of this kind of new compounds were also clearly described. This study provides valuable information for further optimization of PGAM1 inhibitors with 1,3,6,7-tetrahydroxyxanthone backbone or de novo design of novel inhibitor.

Altered glycolysis results in drug-resistant in clinical tumor therapy

Cancer cells undergo metabolic reprogramming, including increased glucose metabolism, fatty acid synthesis and glutamine metabolic rates. These enhancements to three major metabolic pathways are closely associated with glycolysis, which is considered the central component of cancer cell metabolism. Increasing evidence suggests that dysfunctional glycolysis is commonly associated with drug resistance in cancer treatment, and aberrant glycolysis plays a significant role in drug-resistant cancer cells. Studies on the development of drugs targeting these abnormalities have led to improvements in the efficacy of tumor treatment. The present review discusses the changes in glycolysis targets that cause drug resistance in cancer cells, including hexokinase, pyruvate kinase, pyruvate dehydrogenase complex, glucose transporters, and lactate, as well the underlying molecular mechanisms and corresponding novel therapeutic strategies. In addition, the association between increased oxidative phosphorylation and drug resistance is introduced, which is caused by metabolic plasticity. Given that aberrant glycolysis has been identified as a common metabolic feature of drug-resistant tumor cells, targeting glycolysis may be a novel strategy to develop new drugs to benefit patients with drug-resistance.

Expression and Gene Regulation Network of Metabolic Enzyme Phosphoglycerate Mutase Enzyme 1 in Breast Cancer Based on Data Mining

The metabolic enzyme phosphoglycerate mutase enzyme 1 (PGAM1) is a key enzyme in the glycolysis pathway, and glycolysis is closely related to cancer progression, suggesting that PGAM1 may have important functions in breast cancer. We used sequencing data from the Oncomine database and UALCAN database to analyze the expression of PGAM1 and its influence on the clinicopathological characteristics of breast cancer. LinkedOmics was used to identify genes related to PGAM1 expression, kinases, miRNAs, and transcription factors that were significantly related to PGAM1 through GSEA. cBioPortal was used to identify the alternation frequency and form of PGAM1 in breast cancer. The expression level of PGAM1 in breast cancer was significantly higher than that in normal tissues. Moreover, the expression level of PGAM1 is closely related to the molecular subtype and TP53 mutation status. The expression level of PGAM1 in HER2-positive and triple-negative tumors was significantly higher than that of luminal type. The expression level of PGAM1 in TP53-mutant tumors was higher than that in non-TP53-mutant tumors. In addition, the overall survival of patients with high PGAM1 expression was significantly worse than that of patients with low expression ( $P=0.0077$ ). Through GSEA analysis, we found multiple kinases, miRNAs, and transcription factors significantly related to PFKFB4. cBioPortal analysis showed that the mutation rate of PGAM1 in breast cancer was relatively low (4%), and the main form of mutation was high mRNA expression. This study suggests that PGAM1 is a potential diagnostic and prognostic marker in breast cancer. Through data mining, we revealed the potential regulatory network information of PGAM1, laying a foundation for further research on the role of PGAM1 in breast cancer.

Sequenced Combinations of Cisplatin and Selected Phytochemicals towards Overcoming Drug Resistance in Ovarian Tumour Models

In the present study, cisplatin, artemisinin, and oleanolic acid were evaluated alone, and in combination, on human ovarian A2780, A2780^ZD0473R, and A2780^cisR cancer cell lines, with the aim of overcoming cisplatin resistance and side effects. Cytotoxicity was assessed by MTT reduction assay. Combination index (CI) values were used as a measure of combined drug effect. MALDI TOF/TOF MS/MS and 2-DE gel electrophoresis were used to identify protein biomarkers in ovarian cancer and to evaluate combination effects. Synergism from combinations was dependent on concentration and sequence of administration. Generally, bolus was most synergistic. Moreover, 49 proteins differently expressed by 2 ≥ fold were: CYPA, EIF5A1, Op18, p18, LDHB, P4HB, HSP7C, GRP94, ERp57, mortalin, IMMT, CLIC1, NM23, PSA3,1433Z, and HSP90B were down-regulated, whereas hnRNPA1, hnRNPA2/B1, EF2, GOT1, EF1A1, VIME, BIP, ATP5H, APG2, VINC, KPYM, RAN, PSA7, TPI, PGK1, ACTG and VDAC1 were up-regulated, while TCPA, TCPH, TCPB, PRDX6, EF1G, ATPA, ENOA, PRDX1, MCM7, GBLP, PSAT, Hop, EFTU, PGAM1, SERA and CAH2 were not-expressed in A2780^cisR cells. The proteins were found to play critical roles in cell cycle regulation, metabolism, and biosynthetic processes and drug resistance and detoxification. Results indicate that appropriately sequenced combinations of cisplatin with artemisinin (ART) and oleanolic acid (OA) may provide a means to reduce side effects and circumvent platinum resistance.

PGAM1, regulated by miR-3614-5p, functions as an oncogene by activating transforming growth factor-β (TGF-β) signaling in the progression of non-small cell lung carcinoma

Phosphoglycerate mutase 1 (PGAM1) is a recently identified key catalytic enzyme in aerobic glycolysis. Recent literature has documented that dysregulated PGAM1 expression is associated with tumorigenesis in various cancers. However, the expression status and biological function of PGAM1 in non-small-cell lung cancer (NSCLC) are poorly elucidated. In this study, we found that PGAM1 was overexpressed in NSCLC tissues and that high expression of PGAM1 was associated with poor prognosis in NSCLC patients. Functionally, gain- and loss-of-function analysis showed that PGAM1 promoted proliferation and invasion in vitro, and facilitated tumor growth in vivo. Mechanistically, the transforming growth factor-β (TGF-β) signaling pathway was also markedly impaired in response to PGAM1 silencing. Additionally, we verified that PGAM1 was inhibited by miR-3614-5p via direct targeting of its 3’-untranslated regions in a hypoxia-independent manner. Furthermore, overexpression of miR-3614-5p attenuated NSCLC cell proliferation and invasion, and these effects could be partially reversed by reintroduction of PGAM1. Conclusively, our results suggest that the miR-3614-5p/PGAM1 axis plays a critical role during the progression of NSCLC, and these findings may provide a potential target for the development of therapeutic strategies for NSCLC patients.

Phosphoglycerate Mutase 1: Its Glycolytic and Non-Glycolytic Roles in Tumor Malignant Behaviors and Potential Therapeutic Significance

Phosphoglycerate mutase 1 (PGAM1) is an important enzyme that catalyzes the reversible conversion of 3-phosphoglycerate and 2-phosphoglycerate during the process of glycolysis. Increasing evidence suggests that PGAM1 is widely overexpressed in various cancer tissues and plays a significant role in promoting cancer progression and metastasis. Although PGAM1 is a potential target in cancer therapy, the specific mechanisms of action remain unknown. This review introduces the basic structure and functions of PGAM1 and its family members and summarizes recent advances in the role of PGAM1 and various inhibitors of cancer cell proliferation and metastasis from a glycolytic and non-glycolytic perspective. Recent studies have highlighted a correlation between PGAM1 and clinical features and prognosis of cancer as well as the development of target drugs for PGAM1. The integrated information in this review will help better understand the specific roles of PGAM1 in cancer progression. Furthermore, the information highlights the non-glycolytic functions of PGAM1 in tumor metastasis, providing an innovative basis and direction for clinical drug research.

Energy Metabolism in Cancer: The Roles of STAT3 and STAT5 in the Regulation of Metabolism-Related Genes

A central characteristic of many types of cancer is altered energy metabolism processes such as enhanced glucose uptake and glycolysis and decreased oxidative metabolism. The regulation of energy metabolism is an elaborate process involving regulatory proteins such as HIF (pro-metastatic protein), which reduces oxidative metabolism, and some other proteins such as tumour suppressors that promote oxidative phosphorylation. In recent years, it has been demonstrated that signal transducer and activator of transcription (STAT) proteins play a pivotal role in metabolism regulation. STAT3 and STAT5 are essential regulators of cytokine- or growth factor-induced cell survival and proliferation, as well as the crosstalk between STAT signalling and oxidative metabolism. Several reports suggest that the constitutive activation of STAT proteins promotes glycolysis through the transcriptional activation of hypoxia-inducible factors and therefore, the alteration of mitochondrial activity. It seems that STAT proteins function as an integrative centre for different growth and survival signals for energy and respiratory metabolism. This review summarises the functions of STAT3 and STAT5 in the regulation of some metabolism-related genes and the importance of oxygen in the tumour microenvironment to regulate cell metabolism, particularly in the metabolic pathways that are involved in energy production in cancer cells.

A Novel Allosteric Inhibitor of Phosphoglycerate Mutase 1 Suppresses Growth and Metastasis of Non-Small-Cell Lung Cancer

Phosphoglycerate mutase 1 (PGAM1) plays a pivotal role in cancer metabolism and tumor progression via its metabolic activity and interaction with other proteins like α-smooth muscle actin (ACTA2). Allosteric regulation is considered to be an innovative strategy to discover a highly selective and potent inhibitor targeting PGAM1. Here, we identified a novel PGAM1 allosteric inhibitor, HKB99, via structure-based optimization. HKB99 acted to allosterically block conformational change of PGAM1 during catalytic process and PGAM1-ACTA2 interaction. HKB99 suppressed tumor growth and metastasis and overcame erlotinib resistance in non-small-cell lung cancer (NSCLC). Mechanistically, HKB99 enhanced the oxidative stress and altered multiple signaling pathways including the activation of JNK/c-Jun and suppression of AKT and ERK. Collectively, the study highlights the potential of PGAM1 as a therapeutic target in NSCLC and reveals a distinct mechanism by which HKB99 inhibits both metabolic activity and nonmetabolic function of PGAM1 by allosteric regulation.

An allosteric PGAM1 inhibitor effectively suppresses pancreatic ductal adenocarcinoma

Glycolytic enzyme phosphoglycerate mutase 1 (PGAM1) plays a critical role in cancer metabolism by coordinating glycolysis and biosynthesis. A well-validated PGAM1 inhibitor, however, has not been reported for treating pancreatic ductal adenocarcinoma (PDAC), which is one of the deadliest malignancies worldwide. By uncovering the elevated PGAM1 expressions were statistically related to worse prognosis of PDAC in a cohort of 50 patients, we developed a series of allosteric PGAM1 inhibitors by structure-guided optimization. The compound KH3 significantly suppressed proliferation of various PDAC cells by down-regulating the levels of glycolysis and mitochondrial respiration in correlation with PGAM1 expression. Similar to PGAM1 depletion, KH3 dramatically hampered the canonic pathways highly involved in cancer metabolism and development. Additionally, we observed the shared expression profiles of several signature pathways at 12 h after treatment in multiple PDAC primary cells of which the matched patient-derived xenograft (PDX) models responded similarly to KH3 in the 2 wk treatment. The better responses to KH3 in PDXs were associated with higher expression of PGAM1 and longer/stronger suppressions of cancer metabolic pathways. Taken together, our findings demonstrate a strategy of targeting cancer metabolism by PGAM1 inhibition in PDAC. Also, this work provided "proof of concept" for the potential application of metabolic treatment in clinical practice.

Circ-0000284 arouses malignant phenotype of cholangiocarcinoma cells and regulates the biological functions of peripheral cells through cellular communication

Circular RNAs (circRNAs) play a vital role in cancers. Accumulated evidences showed that the physiological condition of cells can be reflected by the circRNAs in the exosomes they secrete, and these exosomal circRNAs can be captured by the receptor cells, thereby inducing a series of cellular responses. We performed qRT-PCR to detect the expression level of circ-0000284 in cholangiocarcinoma cell lines, tissues and plasma exosomes. Then the direct interaction between circ-0000284 and miR-637 was investigated through dual-luciferase reporter assay, RNA binding protein immunoprecipitation (RIP) assay and Fluorescent in situ hybridization (FISH) assay. Subsequently, EdU (5-ethynyl-2'-deoxyuridine), migration, invasion assay, flow cytometry and nude mouse tumorigenicity assay were adopted to evaluate the effect of circ-0000284 on migration, invasion, proliferation and apoptosis of cholangiocarcinoma cells. Additionally, TEM was conducted to investigate the shape and size of exosomes from cholangiocarcioma and 293T cell lines. Circ-0000284 was evidently elevated in cholangiocarcinoma cell lines, tumor tissues and plasma exosomes. Meanwhile, the high expression of circ-0000284 enhanced the migration, invasion and proliferation abilities of cholangiocarcinoma cells in vivo and in vitro Besides, the levels of circ-0000284 were increased in cholangiocarcinoma cells and exosomes from them. Moreover, exosomes from cholangiocarcinoma cells enhanced circ-0000284 expression and stimulated migration and proliferation of the surrounding normal cells. Our findings suggest that on the one hand circ-0000284 functions as a competitive endogenous RNA to promote cholangiocarcinoma progression, and on the other hand, circ-0000284 can be directly transferred from cholangiocarcinoma cells to surrounding normal cells via exosomes and in this way regulate the biological functions of surrounding normal cells.

Metabolic Regulation of Glycolysis and AMP Activated Protein Kinase Pathways during Black Raspberry-Mediated Oral Cancer Chemoprevention

Oral cancer is a public health problem with an incidence of almost 50,000 and a mortality of 10,000 each year in the USA alone. Black raspberries (BRBs) have been shown to inhibit oral carcinogenesis in several preclinical models, but our understanding of how BRB phytochemicals affect the metabolic pathways during oral carcinogenesis remains incomplete. We used a well-established rat oral cancer model to determine potential metabolic pathways impacted by BRBs during oral carcinogenesis. F344 rats were exposed to the oral carcinogen 4-nitroquinoline-1-oxide in drinking water for 14 weeks, then regular drinking water for six weeks. Carcinogen exposed rats were fed a 5% or 10% BRB supplemented diet or control diet for six weeks after carcinogen exposure. RNA-Seq transcriptome analysis on rat tongue, and mass spectrometry and NMR metabolomics analysis on rat urine were performed. We tentatively identified 57 differentially or uniquely expressed metabolites and over 662 modulated genes in rats being fed with BRB. Glycolysis and AMPK pathways were modulated during BRB-mediated oral cancer chemoprevention. Glycolytic enzymes Aldoa, Hk2, Tpi1, Pgam2, Pfkl, and Pkm2 as well as the PKA-AMPK pathway genes Prkaa2, Pde4a, Pde10a, Ywhag, and Crebbp were downregulated by BRBs during oral cancer chemoprevention. Furthermore, the glycolysis metabolite glucose-6-phosphate decreased in BRB-administered rats. Our data reveal the novel metabolic pathways modulated by BRB phytochemicals that can be targeted during the chemoprevention of oral cancer.

Phosphoglycerate mutase 1 in cancer: A promising target for diagnosis and therapy

Altered enzymatic machineries are a substantial biochemical characteristic of tumor cell metabolism that switch metabolic profile from oxidative phosphorylation to amplified glycolysis as well as increased lactate production under hypoxia conditions. Reprogrammed metabolic profile is an emerging hallmark of cancer. Overexpression of several glycolytic enzymes and glucose transporters has been reported in 24 different types of cancers that represent approximately 70% of all the cancer cases around the globe. Thus, targeting glycolytic enzymes could serve as tempting avenue for drug design against cancer. Phosphoglycerate mutase 1 (PGAM1) is an important glycolytic enzyme that catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate. Recent investigations have revealed the overexpression of PGAM1 in several human cancers that is linked with tumor growth, survival, and invasion. The aim of this review is to update scientific research network with cancer-specific role of PGAM1 to elucidate its capability as bonafide therapeutic target for cancer therapy. Moreover, we have also summarized the reported genetic and pharmacological inhibitors of PGAM1. This study suggests that further investigations on PGAM1 should focus on the exploration of molecular mechanisms of PGAM1 overexpression in development of cancer, assessment of biosafety profiles of known inhibitors of PGAM1, and utilization of PGAM1 inhibitors in combinatorial therapies. These future studies will surely support the unbiased strategies for the development of novel PGAM1 inhibitors for cancer therapies.

Analysis of the Antiproliferative Effect of Ankaferd Hemostat on Caco-2 Colon Cancer Cells via LC/MS Shotgun Proteomics Approach

Ankaferd hemostat (ABS), a traditional herbal extract, is a hemostatic agent used for wound healing and bleeding treatment. A standardized form of plants contains many biomolecules. In recent years, previous studies have demonstrated the antineoplastic effect of ABS. In the present work, we focused on the mechanism of its antineoplastic effect over Caco-2 colon cancer cells. The LC/MS-based proteomics method was used to understand the effect of ABS at the protein level. The results were evaluated with gene ontology, protein interaction, and pathway analysis. As shown by our results, ABS altered glucose, fatty acids, and protein metabolism. Moreover, ABS affects the cell cycle machinery. Moreover, we found that ABS induced critical cancer target and suppressor proteins such as carboxyl-terminal hydrolase 1, 60S ribosomal protein L5, Tumor protein D52-like2, karyopherin alpha 2, and protein deglycase DJ-1. In conclusion, the proteomics results indicated that ABS affects various cancer targets and suppressor proteins. Moreover ABS has systematical effect on cell metabolism and cell cycle in Caco-2 cells, suggesting that it could be used as an antineoplastic agent.

Phosphoglycerate mutase 1 knockdown inhibits prostate cancer cell growth, migration, and invasion

Phosphoglycerate mutase 1 (PGAM1) is upregulated in many cancer types and involved in cell proliferation, migration, invasion, and apoptosis. However, the relationship between PGAM1 and prostate cancer is poorly understood. The present study investigated the changes in PGAM1 expression in prostate cancer tissues compared with normal prostate tissues and examined the cellular function of PGAM1 and its relationship with clinicopathological variables. Immunohistochemistry and Western blotting revealed that PGAM1 expression was upregulated in prostate cancer tissues and cell lines. PGAM1 expression was associated with Gleason score (P = 0.01) and T-stage (P = 0.009). Knockdown of PGAM1 by siRNA in PC-3 and 22Rv1 prostate cancer cell lines inhibited cell proliferation, migration, and invasion and enhanced cancer cell apoptosis. In a nude mouse xenograft model, PGAM1 knockdown markedly suppressed tumor growth. Deletion of PGAM1 resulted in decreased expression of Bcl-2, enhanced expression of Bax, caspases-3 and inhibition of MMP-2 and MMP-9 expression. Our results indicate that PGAM1 may play an important role in prostate cancer progression and aggressiveness, and that it might be a valuable marker of poor prognosis and a potential therapeutic target for prostate cancer.

PGAM1 knockdown is associated with busulfan‑induced hypospermatogenesis and spermatogenic cell apoptosis

Phosphoglycerate mutase 1 (PGAM1) is reported to be involved in spermatogenic dysfunction. However, the association between PGAM1 and busulfan-induced hypospermatogenesis and spermatogenic cell apoptosis remains unclear. The aim of the current study was to investigate the association between PGAM1 expression and busulfan-induced hypospermatogenesis, and the effect of PGAM1 expression on spermatogenic cell apoptosis. PGAM1 expression was detected in mouse models of busulfan-induced hypospermatogenesis by western blotting, reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. Then, spermatogenic cell apoptosis in mouse models of busulfan-induced hypospermatogenesis was assessed by TUNEL assay. The effect and potential mechanism of PGAM1 downregulation on spermatogenic cells were further investigated. The results indicated that PGAM1 expression was significantly downregulated in the mouse models of busulfan-induced hypospermatogenesis, compared with those with normal spermatogenesis (P<0.05). Furthermore, the TUNEL assay revealed that the apoptosis of spermatogenic cells was accelerated in the mouse model of busulfan-induced hypospermatogenesis. In addition, PGAM1 knockdown promoted the apoptosis of spermatogenic cells in vitro, which was associated with the P53/Caspase 3/Caspase 6/Caspase 9 signaling pathway. In conclusion, these data indicate that PGAM1 knockdown is associated with busulfan-induced hypospermatogenesis and contributes to spermatogenic cell apoptosis by regulating the P53/Caspase 3/Caspase 6/Caspase 9 signaling pathway.

Identification of the Potential Metabolic Pathways Involved in the Hepatic Tumorigenesis of Rat Diethylnitrosamine-Induced Hepatocellular Carcinoma via 1H NMR-Based Metabolomic Analysis

The systemic investigation of the metabolic pathways associated with the hepatic tumorigenesis is important to discover novel biomarkers and identify the potential pathogenesis. Here, the ¹H nuclear magnetic resonance- (¹H NMR-) based metabolomic analysis was used to monitor the whole process of rat diethylnitrosamine-induced HCC. Intraperitoneal administration of diethylnitrosamine (DEN) was used to induce primary HCCs in male Sprague-Dawley rats. Magnetic resonance imaging (MRI) examinations were performed to follow the tumor formation and growth in the liver and H&E staining was used to confirm MR imaging findings. The rats with DEN treatment and control rats without DEN were euthanized at the time points of 3, 8, and 15 weeks after the start of modeling. ¹H NMR-based metabolomic analysis was used to explore hepatic metabolite changes and certify key metabolic pathways in the process of tumor tumorigenesis. Our MRI results depicted the formation of HCC nodules in ten rats 14 weeks after DEN injection which were confirmed by histology. Twenty-four different metabolites were identified and quantified by ¹H NMR spectroscopy; OPLS-DA models and corresponding VIP plots analysis further identified ten metabolites associated with the abnormal metabolism. The aberrant glucose, lipid, and glutathione-glutamine-glutamate metabolism could be detected involving in the process of hepatic tumorigenesis, which provides an important evidence for the in-depth study of subsequent molecular mechanisms, especially the glutathione-glutamine-glutamate metabolism.

OTUB2 stabilizes U2AF2 to promote the Warburg effect and tumorigenesis via the AKT/mTOR signaling pathway in non-small cell lung cancer

Increasing evidence has confirmed that deubiquitinating enzymes play an important role in lung cancer progression. In the current study, we investigated the expression profile of deubiquitinating enzymes in non-small cell lung cancer (NSCLC) tissues and identified OTUB2 as an upregulated deubiquitinating enzyme. The role of OTUB2 in NSCLC is unknown. Methods: Quantitative, real-time PCR and Western blot were used to detect OTUB2 and U2AF2 expression in NSCLC tissues. The correlations between OTUB2 and U2AF2 expression and clinicopathologic features were then analyzed. We used In vitro Cell Counting Kit-8 (CCK-8) , colony formation , and trans-well invasion assays to investigate the function of OTUB2 and U2AF2 in tumorigenesis. The regulation of glycolysis by OTUB2 and U2AF2 was assessed by determining the extracellular acid ratio, glucose consumption, and lactate production. The mechanism of OTUB2 was explored through co-immunoprecipitation and mass spectrometry analyses. A xenograft model was also used to study the tumorigenesis role of OTUB2 In vivo. Results: OTUB2 expression was significantly upregulated in primary NSCLC tissues and greatly associated with metastasis, advanced tumor stages, poor survival, and recurrence. In NSCLC cell lines, OTUB2 promoted cell growth, colony formation, migration, and invasive activities. Mechanistic investigations showed that OTUB2 stimulated the Warburg effect and induced the activation of the serine/threonine kinase/mechanistic target of rapamycin kinase (AKT/mTOR) pathway in different NSCLC cells. More importantly, OTUB2 promoted NSCLC progression, which was largely dependent on the direct binding to and deubiquitination of U2AF2, at least in NSCLC cells. U2AF2 expression was also significantly upregulated in primary NSCLC tissues and dramatically associated with metastasis, advanced tumor stages, poor survival, and recurrence. Importantly, a positive correlation between the protein expression of OTUB2 and U2AF2 in NSCLC tissues was found. In vivo experiments indicated that OTUB2 promoted xenograft tumor growth of NSCLC cell. In addition, our results suggest that high expression of OTUB2, U2AF2 and PGK1 is significantly associated with worse prognosis in NSCLC patients. Conclusion: Taken together, the present study provides the first evidence that OTUB2 acts as a pivotal driver in NSCLC tumorigenesis by stabilizing U2AF2 and activating the AKT/mTOR pathway and the Warburg effect. It may serve as a new potential prognostic indicator and therapeutic target in NSCLC.

Phosphoglycerate Mutase 1 Promotes Cell Proliferation and Neuroblast Differentiation in the Dentate Gyrus by Facilitating the Phosphorylation of cAMP Response Element-Binding Protein

In a previous study, we observed a significant increase in phosphoglycerate mutase 1 (PGAM1) levels after pyridoxine treatment. In the present study, we investigated the effects of PGAM1 on novel object recognition, cell proliferation, and neuroblast differentiation in the dentate gyrus. We generated a Tat-PGAM1 fusion protein to cross the blood-brain barrier and neuronal plasma membrane. We administered the Tat peptide, control-PGAM1, or Tat-PGAM1 fusion protein to 8-week-old mice once a day for 3 weeks and tested novel object recognition memory. The mice were then euthanized to conduct western blot analysis for polyhistidine expression and immunohistochemical analysis for Ki67, doublecortin, and phosphorylated cAMP response element-binding protein. Mice treated with Tat peptide showed similar exploration times for familiar and new objects and the discrimination index was significantly lower in this group than in the control group. Tat-PGAM1 moderately increased the exploration time of new objects when compared to familiar objects, while the discrimination index was significantly higher in the Tat-PGAM1-treated group, but not in the control-PGAM1-treated group, when compared with the control group. Higher PGAM1 protein expression was observed in the hippocampus of Tat-PGAM1-treated mice when compared with the hippocampi of control, Tat peptide-, and control-PGAM1-treated mice, using western blot analysis. In addition, the numbers of proliferating cells and differentiated neuroblasts were significantly lower in the Tat peptide-treated group than in the control group. In contrast, the numbers of proliferating cells and differentiated neuroblasts in the dentate gyrus were higher in the Tat-PGAM1-treated group than in the control group. Administration of Tat-PGAM1 significantly facilitated the phosphorylation of cAMP response element-binding protein in the dentate gyrus. Administration of control-PGAM1 did not show any significant effects on novel object recognition, cell proliferation, and neuroblast differentiation in the dentate gyrus. These results suggest that PGAM1 plays a role in cell proliferation and neuroblast differentiation in the dentate gyrus via the phosphorylation of cAMP response element-binding protein in the hippocampus.

The Influence of Metabolism on Drug Response in Cancer

Resistance to therapeutic agents, either intrinsic or acquired, is currently a major problem in the treatment of cancers and occurs in virtually every type of anti-cancer therapy. Therefore, understanding how resistance can be prevented, targeted and predicted becomes increasingly important to improve cancer therapy. In the last decade, it has become apparent that alterations in cellular metabolism are a hallmark of cancer cells and that a rewired metabolism is essential for rapid tumor growth and proliferation. Recently, metabolic alterations have been shown to play a role in the sensitivity of cancer cells to widely-used first-line chemotherapeutics. This suggests that metabolic pathways are important mediators of resistance toward anticancer agents. In this review, we highlight the metabolic alterations associated with resistance toward different anticancer agents and discuss how metabolism may be exploited to overcome drug resistance to classical chemotherapy.

Tyrosine Kinase Signaling in Cancer Metabolism: PKM2 Paradox in the Warburg Effect

The Warburg Effect, or aerobic glycolysis, is one of the major metabolic alterations observed in cancer. Hypothesized to increase a cell's proliferative capacity via regenerating NAD⁺, increasing the pool of glycolytic biosynthetic intermediates, and increasing lactate production that affects the tumor microenvironment, the Warburg Effect is important for the growth and proliferation of tumor cells. The mechanisms by which a cell acquires the Warburg Effect phenotype are regulated by the expression of numerous oncogenes, including oncogenic tyrosine kinases. Oncogenic tyrosine kinases play a significant role in phosphorylating and regulating the activity of numerous metabolic enzymes. Tyrosine phosphorylation of glycolytic enzymes increases the activities of a majority of glycolytic enzymes, thus promoting increased glycolytic rate and tumor cell proliferation. Paradoxically however, tyrosine phosphorylation of pyruvate kinase M2 isoform (PKM2) results in decreased PKM2 activity, and this decrease in PKM2 activity promotes the Warburg Effect. Furthermore, recent studies have shown that PKM2 is also able to act as a protein kinase using phosphoenolpyruvate (PEP) as a substrate to promote tumorigenesis. Therefore, numerous recent studies have investigated both the role of the classical and non-canonical activity of PKM2 in promoting the Warburg Effect and tumor growth, which raise further interesting questions. In this review, we will summarize these recent advances revealing the importance of tyrosine kinases in the regulation of the Warburg Effect as well as the role of PKM2 in the promotion of tumor growth.

Clinical Proteomics: Closing the Gap from Discovery to Implementation

Clinical proteomics, the application of proteome analysis to serve a clinical purpose, represents a major field in the area of proteome research. Over 1000 manuscripts on this topic are published each year, with numbers continuously increasing. However, the anticipated outcome, the transformation of the reported findings into improvements in patient management, is not immediately evident. In this article, the value and validity of selected clinical proteomics findings are investigated, and it is assessed how far implementation has progressed. A main conclusion from this assessment is that to achieve implementation, well-powered clinical studies are required in the appropriate population, addressing a specific clinical need and with a clear context-of-use. Efforts toward implementation, to be feasible, must be supported by the key players in science: publishers and funders. The authors propose a change on objectives, from additional discovery studies toward studies aiming at validation of the plethora of potential biomarkers that have been described, to demonstrate practical value of clinical proteomics. All elements required, potential biomarkers, technologies, and bio-banked samples are available (based on today's literature), hence a change in focus from discovery toward validation and application is not only urgently necessary, but also possible based on resources available today.

Identification of PGAM1 as a putative therapeutic target for pancreatic ductal adenocarcinoma metastasis using quantitative proteomics

Background

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive gastrointestinal cancer characterized by an extremely low survival rate because of early metastasis. Identifying satisfactory therapeutic targets associated with metastasis is crucial to improve the treatment effect of PDAC.

Materials and methods

In this research, we used stable isotope labeling by amino acids in cell culture, 1-dodecyl-3-methylimidazolium chloride-assisted sample preparation method preparing protein sample and nano-reversed-phase liquid chromatography-mass spectrometry/mass spectrometry analysis to perform the comparative proteomics of two homologous hamster pancreatic cancer cell lines that are different in metastatic ability: PC-1.0 (highly metastatic) and PC-1 (weakly metastatic). Verifications are through immunohistochemistry on clinical human PDAC pathologic tissues as well as by Western blot of human pancreatic cancer cell lines. siRNA silencing methods were used to study the effect of molecules on invasion and metastasis of pancreatic cancer cell lines.

Results

Bioinformatic analysis indicated that a total of 141 differentially expressed proteins (82 upregulated and 59 downregulated in PC-1.0 cells) were identified showing obviously differential expression (>1.5-fold change). These differentially expressed proteins were involved in a number of different biologic functions, metabolic pathways, and pathophysiologic processes. Phosphoglycerate mutase 1 (PGAM1) and HSPE1 are the top two upregulated proteins, and PDIA3 and CALR are the top two downregulated proteins in PC-1.0 cells compared to PC-1 cells. PGAM1 and HSPE1 showed higher expressions in PDAC tissue with clinical metastasis and highly metastatic pancreatic cancer cell lines PC-1.0 and Aspc-1. PDIA3 and CALR showed higher expressions in weakly metastatic pancreatic cancer cell lines PC-1 and Capan-2. The Western blot results were consistent with the MS quantification data. Silencing PGAM1 was found to decrease the migration and invasion of pancreatic cancer cell lines with statistical significance, especially in highly metastatic PC-1.0 and Aspc-1 cell lines.

Conclusion

These data indicated that PGAM1 may be a potential therapeutic target for PDAC metastasis.

Phosphoglycerate mutase 1 is highly expressed in C6 glioma cells and human astrocytoma

The aim of the present study was to examine the expression of phosphoglycerate mutase 1 (PGAM1) in astrocytomas, and to investigate its role in the progression of astrocytomas. The expression of PGAM1 mRNA in rat C6 glioma cells and normal astrocytes was determined using the reverse transcription-semi-quantitative polymerase chain reaction, and immunohistochemistry was used to detect the expression of PGAM1 protein in human astrocytomas and adjacent brain tissue. These data suggested that the expression of PGAM1 in rat C6 glioma cells was significantly increased compared with that of normal astrocytes (P<0.05), and the expression of PGAM1 protein in human astrocytoma tissue was significantly increased compared with that of the brain tissue surrounding the tumor (P<0.05). In addition, PGAM1 protein was more frequently expressed in high-grade astrocytomas compared with low-grade astrocytomas. These data indicate that the expression of PGAM1 is increased in C6 cells and human astrocytomas, and PGAM1 is probably involved in the tumorigenesis and progression of glioma, which may be a potential target for glioma treatment.

The crucial role of multiomic approach in cancer research and clinically relevant outcomes

Cancer with heavily economic and social burden is the hot point in the field of medical research. Some remarkable achievements have been made; however, the exact mechanisms of tumor initiation and development remain unclear. Cancer is a complex, whole-body disease that involves multiple abnormalities in the levels of DNA, RNA, protein, metabolite and medical imaging. Biological omics including genomics, transcriptomics, proteomics, metabolomics and radiomics aims to systematically understand carcinogenesis in different biological levels, which is driving the shift of cancer research paradigm from single parameter model to multi-parameter systematical model. The rapid development of various omics technologies is driving one to conveniently get multi-omics data, which accelerates predictive, preventive and personalized medicine (PPPM) practice allowing prediction of response with substantially increased accuracy, stratification of particular patients and eventual personalization of medicine. This review article describes the methodology, advances, and clinically relevant outcomes of different "omics" technologies in cancer research, and especially emphasizes the importance and scientific merit of integrating multi-omics in cancer research and clinically relevant outcomes.

Metabo-Devo: A metabolic perspective of development

In the last years, several reports have established the notion that metabolism is not just a housekeeping process, but instead an active effector of physiological changes. The idea that the metabolic status may rule a wide range of phenomena in cell biology is starting to be broadly accepted. Thus, current developmental biology has begun to describe different ways by which the metabolic profile of the cell and developmental programs of the organism can crosstalk. In this review, we discuss mechanisms by which metabolism impacts on processes governing development. We review the growing body of evidence that supports the notion that aerobic glycolysis is required in cells undergoing fast growth and high proliferation, similarly to the Warburg effect described in tumor cells. Glycolytic metabolism explains not only the higher ATP synthesis rate required for cell growth, but also the uncoupling between mitochondrial activity and bioenergetics needed to provide anabolism with sufficient precursors. We also discuss some recent studies, which show that in addition to its role in providing energy and carbon chains, the metabolic status of the cell can also influence epigenetic regulation of developmental processes. Although metabolic aspects of development are just starting to be explored, there is no doubt that ongoing research in this field will shape the future landscape of Developmental Biology.

Global Analyses of Selective Insulin Resistance in Hepatocytes Caused by Palmitate Lipotoxicity

Obesity is tightly linked to hepatic steatosis and insulin resistance. One feature of this association is the paradox of selective insulin resistance: insulin fails to suppress hepatic gluconeogenesis but activates lipid synthesis in the liver. How lipid accumulation interferes selectively with some branches of hepatic insulin signaling is not well understood. Here we provide a resource, based on unbiased approaches and established in a simple cell culture system, to enable investigations of the phenomenon of selective insulin resistance. We analyzed the phosphoproteome of insulin-treated human hepatoma cells and identified sites in which palmitate selectively impairs insulin signaling. As an example, we show that palmitate interferes with insulin signaling to FoxO1, a key transcription factor regulating gluconeogenesis, and identify altered FoxO1 cellular compartmentalization as a contributing mechanism for selective insulin resistance. This model system, together with our comprehensive characterization of the proteome, phosphoproteome, and lipidome changes in response to palmitate treatment, provides a novel and useful resource for unraveling the mechanisms underlying selective insulin resistance.

Phosphoglycerate Mutase 1 (PGAM1) Promotes Pancreatic Ductal Adenocarcinoma (PDAC) Metastasis by Acting as a Novel Downstream Target of the PI3K/Akt/mTOR Pathway

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors known, with an overall 5-year survival rate of less than 6% due to early local invasion and distant metastasis. Exploring suitable therapeutic targets associated with invasion and metastasis is required for improving the prognosis of PDAC. In this study, we investigated the role of the glycolytic enzyme phosphoglycerate mutase 1 (PGAM1) in PDAC. PGAM1 expression was examined in tissue samples of 54 PDAC patients using immunohistochemistry, and the correlation between clinicopathological expression and PGAM1 expression was determined. A survival curve was generated using the Kaplan–Meier method. After silencing PGAM1 by siRNA in pancreatic cancer cell lines Aspc-1 and Panc-1, the changes in proliferation, migration, and invasion, and signal pathways were determined. In this study, the expression of PGAM1 was found positively related to poor differentiation, metastasis, advanced clinical stage, and poor survival rate. Silencing PGAM1 decreased the proliferation of Aspc-1 and Panc-1 cells with an S phase arrest, but without influencing cell apoptosis. Migration and invasion also decreased significantly, independent of proliferation. PGAM1 was also found to promote EMT of PDAC cell lines by regulating the Wnt/β-catenin pathway. PGAM1 itself was modulated by the PI3K/Akt/mTOR pathway as a novel downstream target and has a positive mutual regulation with HIF-1α. This study indicates that PGAM1 is closely associated with clinical metastasis and poor prognosis of PDAC. PGAM1 is considered as a potential therapeutic target in PDAC metastasis.

Phosphoglyceric acid mutase-1 contributes to oncogenic mTOR-mediated tumor growth and confers non-small cell lung cancer patients with poor prognosis

As a hallmark of cancer, the Warburg effect (aerobic glycolysis) confers a selective advantage for the survival and proliferation of cancer cells. Due to frequent aberration of upstream proto-oncogenes and tumor suppressors, hyperactive mammalian/mechanistic target of rapamycin (mTOR) is a potent inducer of the Warburg effect. Here, we report that overexpression of a glycolytic enzyme, phosphoglyceric acid mutase-1 (PGAM1), is critical to oncogenic mTOR-mediated Warburg effect. mTOR stimulated PGAM1 expression through hypoxia-inducible factor 1α-mediated transcriptional activation. Blockage of PGAM1 suppressed mTOR-dependent glycolysis, cell proliferation, and tumorigenesis. PGAM1 expression and mTOR activity were positively correlated in non-small cell lung cancer (NSCLC) tissues and PGAM1 abundance was an adverse predictor for patient survival. PGAM1 is thus a downstream effector of mTOR signaling pathway and mTOR-PGAM1 signaling cascade may contribute to the development of Warburg effect observed in cancer. We consider PGAM1 as a novel prognostic biomarker for NSCLC and a therapeutic target for cancer.

Conformation and dynamics of the C-terminal region in human phosphoglycerate mutase 1

Phosphoglycerate mutase 1 (PGAM1), an important enzyme in glycolysis, is overexpressed in a number of human cancers, thus has been proposed as a promising metabolic target for cancer treatments. The C-terminal portion of the available crystal structures of PGAM1 and its homologous proteins is partially disordered, as evidenced by weak electron density. In this study, we identified the conformational behavior of the C-terminal region of PGAM1 as well as its role during the catalytic cycle. Using the PONDR-FIT server, we demonstrated that the C-terminal region was intrinsically disordered. We applied the Monte Carlo (MC) method to explore the conformational space of the C-terminus and conducted a series of explicit-solvent molecular dynamics (MD) simulations, and revealed that the C-terminal region is inherently dynamic; large-scale conformational changes in the C-terminal segment led to the structural transition of PGAM1 from the closed state to the open state. Furthermore, the C-terminal segment influenced 2,3-bisphosphoglycerate (2,3-BPG) binding. The proposed swing model illustrated a critical role of the C-terminus in the catalytic cycle through the conformational changes. In conclusion, the C-terminal region induces large movements of PGAM1 from the closed state to the open state and influences cofactor binding during the catalytic cycle. This report describes the dynamic features of the C-terminal region in detail and should aid in design of novel and efficient inhibitors of PGAM1. A swing mechanism of the C-terminal region is proposed, to facilitate further studies of the catalytic mechanism and the physiological functions of its homologues.