Enhanced expression of the M2 isoform of pyruvate kinase is involved in gastric cancer development by regulating cancer-specific metabolism

Costimulation with high-fat diet and acidic bile salts may promote Warburg effect in gastric carcinogenesis around the squamocolumnar junction in Gan mice

Epidemiological studies demonstrated relationships between gastric cardia adenocarcinoma (GCA) and metabolic syndrome (MetS). We aimed to clarify the mechanism underlying their relationship. To investigate whether systemic inflammation against high-fat diet (HFD)-related dysbiosis promotes the Warburg effect in tumors at the squamocolumnar junction (SCJ), we applied K19-Wnt1/C2mE (Gan) mice, fed either HFD or control diet ± acidic bile salts (ABS) with/without clodronate liposomes (CLs), and in vitro studies using MKN7 cells with/without THP1-derived macrophages. Then, we assessed the involvement of oxidative stress (OS) in the Warburg effect by comparing nuclear factor-erythroid 2-related factor 2 (Nrf2) knockout Gan mice with Gan mice. Tumors with macrophage infiltration in the HFD + ABS group were larger than in the control group. Gene Set Enrichment Analysis revealed enhancement of the OS signaling in tumor of the HFD + ABS group. The HFD + ABS group mice demonstrated induction of OS, Nqo1, tumor necrosis factor alpha (TNFα), and the Warburg effect in tumors and mucosal barrier dysfunction of dysbiotic gut. All of them were abolished with diminishing macrophage infiltration by additional CL treatment. Stimulation with TNFα, but not ABS nor lipopolysaccharide, on MKN7 cells activated the Warburg effect. In MKN7 cells cocultured with the macrophages whose TNFα expression was induced by the lipopolysaccharide pretreatment, the Warburg effect was enhanced in TNFα concentration-dependent manners. In Nrf2 knockout Gan mice, tumors shrank with reducing OS, TNFα, and Warburg effect, along with decreasing macrophage infiltration. Accordingly, MetS may develop GCA through the Nrf2-related Warburg effect under the TNFα stimulation from the macrophages activated by both local ABS exposure and systemic lipopolysaccharide exposure from leaky gut with HFD-related dysbiosis.NEW & NOTEWORTHY In K19-Wnt1/C2mE (Gan) mice, a high-fat diet accompanied by orally taking acidic bile salts (ABS) promoted inflammation-associated carcinogenesis at the squamocolumnar junction (SCJ), maybe due to transudates from dysbiotic gut into systemic circulation. Systemic lipopolysaccharide exposure and local ABS exposure at the SCJ activate macrophages to induce the expressions of nuclear factor-erythroid 2-related factor 2 (Nrf2) and TNFα, which might promote Warburg effect in cancer cells. These phenomena were abolished in the Nrf2-knockout Gan mice.

Electrochemical assay for the quantification of anticancer drugs and their inhibition mechanism

Overexpression of pyruvate kinase (PyK) is linked to many kinds of malignant tumors, representing therefore one of the most promising therapeutic targets for cancer treatment. Inhibition of PyK slows down tumor growth or causes tumor cell death, minimizing cancer cell proliferation, and understanding inhibitor mechanism of action can significantly improve cancer therapy. The present work describes the use of an amperometric bienzymatic biosensor, based on PyK and pyruvate oxidase (PyOx), in enzyme inhibition studies of four kinase inhibitors, CPG77675, Nilotinib, Ruxolitinib, Cerdulatinib. Their inhibition mechanism is studied and discussed in detail, with a thorough evaluation of their enzyme-inhibitor complex binding constants (Ki) and the inhibitor concentration required for 50% inhibition (IC50), employing standard inhibition procedure graphical methods. The biosensor is successfully applied for the quantification of the inhibitors by fixed potential amperometry, with excellent detection limit values in the pM range. It is the first detection method reported for the anticancer drugs CPG77675 and Cerdulatinib. The electrochemical assay based on the biosensor brings several advantages over the available assay kits for high-throughput screening (HTS) of kinase inhibitors, namely: low cost, easy operability and robustness demonstrated by biosensor high reproducibility and both operational and storage stability, offering an opportunity to discover new inhibitors and optimize their therapeutic index.

PRDX2 promotes gastric cancer progression by forming a feedback loop with PKM2/STAT3 axis

Peroxiredoxin 2 (PRDX2) is an antioxidant enzyme that has been reported to be overexpressed in various cancers. However, the role of PRDX2 in gastric cancer progression and its underlying mechanism remains unclear. Herein, we revealed the function of PRDX2 in gastric cancer progression and explored its molecule mechanism. We identified that PRDX2 was upregulated and associated with poor prognosis in gastric cancer. The knockdown of PRDX2 inhibited the proliferation, migration and invasion of gastric cancer cells in vitro and suppressed tumor growth in vivo. Mechanistically, PRDX2 interacted with PKM2 (pyruvate kinase isozyme type M2) and protected PKM2 from ubiquitination and degradation, which enhanced glycolysis in gastric cancer cells. The interaction between PRDX2 and PKM2 also enhanced the binding affinity between PKM2 and importin α5, which induced PKM2 nuclear translocation and activated STAT3 signaling pathway. In addition, STAT3 (signal transducer and activator of transcription 3) was identified to bind to PRDX2 gene promoter and upregulate PRDX2 expression, which forms a positive regulatory feedback loop in gastric cancer cells. The present study unravels the biological role of PRDX2 in cancer progression and illustrates the underlying molecular mechanism, which may provide a potential therapeutic target for gastric cancer.

Association of Helicobacter pylori CagA seropositivity with gastric precancerous lesions: a systematic review and meta-analysis

The objective of this meta-analysis is to delineate the association between H. pylori CagA serological status and the prevalence of gastric precancerous lesions (GPL). We searched peer-reviewed articles up to October 2023. The extraction of data from the included studies was carried out as well as the quality assessment. Pooled effect sizes were calculated using a random effect model. Thirteen studies met the inclusion criteria, comprising 2728 patients with GPL and 17 612 controls. The aggregate odds ratio (OR) for the association between serum CagA and GPL was 2.74 (95% CI = 2.25-3.32; P  = 0.00; I 2  = 60.4%), irrespective of H. pylori infection status. Within the H. pylori -infected cohort, the OR was 2.25 (95% CI = 1.99-2.56; P  = 0.00; I 2  = 0.0%). Conversely, among the non-infected individuals, the OR was 1.63 (95% CI = 1.04-2.54; P  = 0.038; I 2  = 0.0%). Heterogeneity was explored using subgroup and meta-regression analyses, indicating that the variability between studies likely stemmed from differences in disease classification. Our results demonstrated robustness and negligible publication bias. The meta-analysis underscores a more pronounced association between H. pylori CagA seropositivity and the risk of developing GPL than between seronegativity and the same risk, irrespective of H. pylori infection status at the time. Additionally, the strength of the association was heightened in the presence of an active H. pylori infection. The implications of these findings advocate for the utility of CagA serostatus as a potential biomarker for screening GPL.

All-trans-retinoic acid modulates glycolysis via H19 and telomerase: the role of mir-let-7a in estrogen receptor-positive breast cancer cells

BACKGROUND

Breast cancer (BC) is the most commonly diagnosed cancer in women. Treatment approaches that differ between estrogen-positive (ER+) and triple-negative BC cells (TNBCs) and may subsequently affect cancer biomarkers, such as H19 and telomerase, are an emanating delight in BC research. For instance, all-trans-Retinoic acid (ATRA) could represent a potent regulator of these oncogenes, regulating microRNAs, mostly let-7a microRNA (miR-let-7a), which targets the glycolysis pathway, mainly pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) enzymes. Here, we investigated the potential role of ATRA in H19, telomerase, miR-let-7a, and glycolytic enzymes modulation in ER + and TNBC cells.

METHODS

MCF-7 and MDA-MB-231 cells were treated with 5 µM ATRA and/or 100 nM fulvestrant. Then, ATRA-treated or control MCF-7 cells were transfected with either H19 or hTERT siRNA. Afterward, ATRA-treated or untreated MDA-MB-231 cells were transfected with estrogen receptor alpha ER(α) or beta ER(β) expression plasmids. RNA expression was evaluated by RT‒qPCR, and proteins were assessed by Western blot. PKM2 activity was measured using an NADH/LDH coupled enzymatic assay, and telomerase activity was evaluated with a quantitative telomeric repeat amplification protocol assay. Student's t-test or one-way ANOVA was used to analyze data from replicates.

RESULTS

Our results showed that MCF-7 cells were more responsive to ATRA than MDA-MB-231 cells. In MCF-7 cells, ATRA and/or fulvestrant decreased ER(α), H19, telomerase, PKM2, and LDHA, whereas ER(β) and miR-let-7a increased. H19 or hTERT knockdown with or without ATRA treatment showed similar results to those obtained after ATRA treatment, and a potential interconnection between H19 and hTERT was found. However, in MDA-MB-231 cells, RNA expression of the aforementioned genes was modulated after ATRA and/or fulvestrant, with no significant effect on protein and activity levels. Overexpression of ER(α) or ER(β) in MDA-MB-231 cells induced telomerase activity, PKM2 and LDHA expression, in which ATRA treatment combined with plasmid transfection decreased glycolytic enzyme expression.

CONCLUSIONS

To the best of our knowledge, our study is the first to elucidate a new potential interaction between the estrogen receptor and glycolytic enzymes in ER + BC cells through miR-let-7a.

Targeting the Metabolic Paradigms in Cancer and Diabetes

Dysregulated metabolic dynamics are evident in both cancer and diabetes, with metabolic alterations representing a facet of the myriad changes observed in these conditions. This review delves into the commonalities in metabolism between cancer and type 2 diabetes (T2D), focusing specifically on the contrasting roles of oxidative phosphorylation (OXPHOS) and glycolysis as primary energy-generating pathways within cells. Building on earlier research, we explore how a shift towards one pathway over the other serves as a foundational aspect in the development of cancer and T2D. Unlike previous reviews, we posit that this shift may occur in seemingly opposing yet complementary directions, akin to the Yin and Yang concept. These metabolic fluctuations reveal an intricate network of underlying defective signaling pathways, orchestrating the pathogenesis and progression of each disease. The Warburg phenomenon, characterized by the prevalence of aerobic glycolysis over minimal to no OXPHOS, emerges as the predominant metabolic phenotype in cancer. Conversely, in T2D, the prevailing metabolic paradigm has traditionally been perceived in terms of discrete irregularities rather than an OXPHOS-to-glycolysis shift. Throughout T2D pathogenesis, OXPHOS remains consistently heightened due to chronic hyperglycemia or hyperinsulinemia. In advanced insulin resistance and T2D, the metabolic landscape becomes more complex, featuring differential tissue-specific alterations that affect OXPHOS. Recent findings suggest that addressing the metabolic imbalance in both cancer and diabetes could offer an effective treatment strategy. Numerous pharmaceutical and nutritional modalities exhibiting therapeutic effects in both conditions ultimately modulate the OXPHOS-glycolysis axis. Noteworthy nutritional adjuncts, such as alpha-lipoic acid, flavonoids, and glutamine, demonstrate the ability to reprogram metabolism, exerting anti-tumor and anti-diabetic effects. Similarly, pharmacological agents like metformin exhibit therapeutic efficacy in both T2D and cancer. This review discusses the molecular mechanisms underlying these metabolic shifts and explores promising therapeutic strategies aimed at reversing the metabolic imbalance in both disease scenarios.

USP4 promotes the proliferation and glucose metabolism of gastric cancer cells by upregulating PKM2

BACKGROUND

The pyruvate kinase enzyme PKM2 catalyzes the final step in glycolysis and converts phosphoenolpyruvate (PEP) to pyruvate. PKM2 is often overexpressed in cancer and plays a role in the Warburg effect. The expression of PKM2 can be regulated at different levels. While it has been proven that PKM2 can be regulated by ubiquitination, little is known about its de-ubiquitination regulation.

METHODS

Immunoprecipitation was applied to identify the PKM2 interaction protein and to determine the interaction region between PKM2 and USP4. Immunofluorescence was performed to determine the cellular localization of USP4 and PKM2. The regulation of PKM2 by USP4 was examined by western blot and ubiquitination assay. MTT assays, glucose uptake, and lactate production were performed to analyze the biological effects of USP4 in gastric cancer cells.

RESULTS

USP4 interacts with PKM2 and catalyzes the de-ubiquitination of PKM2. Overexpression of USP4 promotes cell proliferation, glucose uptake, and lactate production in gastric cancer cells. Knockdown of USP4 reduces PKM2 levels and results in a reduction in cell proliferation and the glycolysis rate.

CONCLUSIONS

USP4 plays a tumor-promoting role in gastric cancer cells by regulating PKM2.

Natural epidithiodiketopiperazine alkaloids as potential anticancer agents: Recent mechanisms of action, structural modification, and synthetic strategies

Cancer has become a grave health crisis that threatens the lives of millions of people worldwide. Because of the drawbacks of the available anticancer drugs, the development of novel and efficient anticancer agents should be encouraged. Epidithiodiketopiperazine (ETP) alkaloids with a 2,5-diketopiperazine (DKP) ring equipped with transannular disulfide or polysulfide bridges or S-methyl moieties constitute a special subclass of fungal natural products. Owing to their privileged sulfur units and intriguing architectural structures, ETP alkaloids exhibit excellent anticancer activities by regulating multiple cancer proteins/signaling pathways, including HIF-1, NF-κB, NOTCH, Wnt, and PI3K/AKT/mTOR, or by inducing cell-cycle arrest, apoptosis, and autophagy. Furthermore, a series of ETP alkaloid derivatives obtained via structural modification showed more potent anticancer activity than natural ETP alkaloids. To solve supply difficulties from natural resources, the total synthetic routes for several ETP alkaloids have been designed. In this review, we summarized several ETP alkaloids with anticancer properties with particular emphasis on their underlying mechanisms of action, structural modifications, and synthetic strategies, which will offer guidance to design and innovate potential anticancer drugs.

Down-regulation of NOTCH1 and PKM2 can inhibit the growth and metastasis of colorectal cancer cells

BACKGROUND

Previous studies have revealed the overexpression of Notch receptor 1 (NOTCH1) and pyruvate kinase M2 (PKM2) in colorectal cancer (CRC) tissue and their relationship to disease development. However, whether there is synergy between PKM2 and NOTCH1 needs to be verified. This study aims to analyze the mechanism and relationship between NOTCH1 and PKM2 in CRC.

METHODS

Immunohistochemistry was used to measure the expression of NOTCH1 and PKM2 in colorectal cancer, and the correlation between them was analyzed by Pearson test. The protein and mRNA expressions in CRC cell lines were determined by western blot (WB) and real-time quantitative reverse transcription PCR (qRT-PCR). Compound 3K and tangeretin (TGN) were used to inhibit the expressions of PKM2 and NOTCH1, respectively. The wound healing assay and CCK-8 assay were applied to measure the migration and proliferation of cancer cells.

RESULTS

Immunohistochemical analysis showed that NOTCH1 and PKM2 were overexpressed in patients with colorectal cancer, and patients with overexpression showed a higher number of lymph node metastases and high tumor stage (III+IV) (P<0.05). In addition, Pearson test showed that the level of NOTCH1 was positively correlated with the level of PKM2 (P<0.05). WB and qRT-PCR showed that the protein and mRNA levels of NOTCH1 and PKM2 in colorectal cancer cells were significantly up-regulated (P<0.05). The inhibition of PKM2 and NOTCH1 had a synergistic effect on reducing the invasion and proliferation of CRC cells.

CONCLUSION

NOTCH1 and PKM2 are highly expressed in CRC patients. Inhibiting the expression of NOTCH1 and PKM2 can inhibit the growth and metastasis of CRC cells, providing therapeutic targets for the treatment of CRC.

CagA and VacA inhibit gastric mucosal epithelial cell autophagy and promote the progression of gastric precancerous lesions

Cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) are the keys to the pathogenic role of Helicobacter pylori and the high-risk factors for the progression of gastric precancerous lesions. Autophagy can stabilize the intracellular environment, resist Helicobacter pylori infection, prevent the accumulation of damaged DNA, and inhibit the proliferation of gastric precancerous variant cells. However, CagA and VacA can inhibit the activation of upstream signals of autophagy and the maturation of autophagy-lysosomes in various ways, thus inhibiting the autophagy of gastric mucosal cells in precancerous lesions of gastric cancer. This change can cause Helicobacter pylori to be unable to be effectively cleared by autophagy, so CagA and VacA can persist and promote the inflammation, oxidative stress, apoptosis of gastric mucosal tissue cells, and the glycolytic activity and proliferation of variant cells in gastric precancerous lesions and a series of malignant biological processes. In recent years, the research on drugs specifically inhibiting the activities of CagA and VacA has become a new direction for the prevention and treatment of Helicobacter pylori-related severe gastric diseases, and a variety of drugs or components that can precisely and effectively regulate the factors for the treatment of gastric precancerous lesions are emerged, which opens a new strategy for the treatment of gastric precancerous lesions in the future.

A Novel Necroptosis-Related Gene Signature in Skin Cutaneous Melanoma Prognosis and Tumor Microenvironment

Background: Necroptosis has been identified recently as a newly recognized programmed cell death that has an impact on tumor progression and prognosis, although the necroptosis-related gene (NRGs) potential prognostic value in skin cutaneous melanoma (SKCM) has not been identified. The aim of this study was to construct a prognostic model of SKCM through NRGs in order to help SKCM patients obtain precise clinical treatment strategies. Methods: RNA sequencing data collected from The Cancer Genome Atlas (TCGA) were used to identify differentially expressed and prognostic NRGs in SKCM. Depending on 10 NRGs via the univariate Cox regression analysis usage and LASSO algorithm, the prognostic risk model had been built. It was further validated by the Gene Expression Omnibus (GEO) database. The prognostic model performance had been assessed using receiver operating characteristic (ROC) curves. We evaluated the predictive power of the prognostic model for tumor microenvironment (TME) and immunotherapy response. Results: We constructed a prognostic model based on 10 NRGs (FASLG, TLR3, ZBP1, TNFRSF1B, USP22, PLK1, GATA3, EGFR, TARDBP, and TNFRSF21) and classified patients into two high- and low-risk groups based on risk scores. The risk score was considered a predictive factor in the two risk groups regarding the Cox regression analysis. A predictive nomogram had been built for providing a more beneficial prognostic indicator for the clinic. Functional enrichment analysis showed significant enrichment of immune-related signaling pathways, a higher degree of immune cell infiltration in the low-risk group than in the high-risk group, a negative correlation between risk scores and most immune checkpoint inhibitors (ICIs), anticancer immunity steps, and a more sensitive response to immunotherapy in the low-risk group. Conclusions: This risk score signature could be applied to assess the prognosis and classify low- and high-risk SKCM patients and help make the immunotherapeutic strategy decision.

Candidate therapeutic agents in a newly established triple wild-type mucosal melanoma cell line

BACKGROUND

Mucosal melanoma has characteristically distinct genetic features and typically poor prognosis. The lack of representative mucosal melanoma models, especially cell lines, has hindered translational research on this melanoma subtype. In this study, we aimed to establish and provide the biological properties, genomic features and the pharmacological profiles of a mucosal melanoma cell line that would contribute to the understanding and treatment optimization of molecularly-defined mucosal melanoma subtype.

METHODS

The sample was collected from a 67-year-old mucosal melanoma patient and processed into pieces for the establishment of cell line and patient-derived xenograft (PDX) model. The proliferation and tumorigenic property of cancer cells from different passages were evaluated, and whole-genome sequencing (WGS) was performed on the original tumor, PDX, established cell line, and the matched blood to confirm the establishment and define the genomic features of this cell line. AmpliconArchitect was conducted to depict the architecture of amplified regions detected by WGS. High-throughput drug screening (HTDS) assay including a total of 103 therapeutic agents was implemented on the established cell line, and selected candidate agents were validated in the corresponding PDX model.

RESULTS

A mucosal melanoma cell line, MM9H-1, was established which exhibited robust proliferation and tumorigenicity after more than 100 serial passages. Genomic analysis of MM9H-1, corresponding PDX, and the original tumor showed genetic fidelity across genomes, and MM9H-1 was defined as a triple wild-type (TWT) melanoma subtype lacking well-characterized "driver mutations". Instead, the amplification of several oncogenes, telomerase reverse transcriptase (TERT), v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), melanocyte Inducing transcription factor (MITF) and INO80 complex ATPase subunit (INO80), via large-scale genomic rearrangement potentially contributed to oncogenesis of MM9H-1. Moreover, HTDS identified proteasome inhibitors, especially bortezomib, as promising therapeutic candidates for MM9H-1, which was verified in the corresponding PDX model in vivo.

CONCLUSIONS

We established and characterized a new mucosal melanoma cell line, MM9H-1, and defined this cell line as a TWT melanoma subtype lacking well-characterized "driver mutations". The MM9H-1 cell line could be adopted as a unique model for the preclinical investigation of mucosal melanoma.

Progress in Metabolic Studies of Gastric Cancer and Therapeutic Implications

Background:

Worldwide, gastric cancer is ranked the fifth malignancy in incidence and the third malignancy in mortality. Gastric cancer causes an altered metabolism that can be therapeutically exploited.

Objective:

To provide an overview of the significant metabolic alterations caused by gastric cancer and propose a blockade.

Methods:

A comprehensive and up-to-date review of descriptive and experimental publications on the metabolic alterations caused by gastric cancer and their blockade. This is not a systematic review.

Results:

Gastric cancer causes high rates of glycolysis and glutaminolysis. There are increased rates of de novo fatty acid synthesis and cholesterol synthesis. Moreover, gastric cancer causes high rates of lipid turnover via fatty acid -oxidation. Preclinical data indicate that the individual blockade of these pathways via enzyme targeting leads to antitumor effects in vitro and in vivo. Nevertheless, there is no data on the simultaneous blockade of these five pathways, which is critical, as tumors show metabolic flexibility in response to the availability of nutrients. This means tumors may activate alternate routes when one or more are inhibited. We hypothesize there is a need to simultaneously blockade them to avoid or decrease the metabolic flexibility that may lead to treatment resistance.

Conclusions:

There is a need to explore the preclinical efficacy and feasibility of combined metabolic therapy targeting the pathways of glucose, glutamine, fatty acid synthesis, cholesterol synthesis, and fatty acid oxidation. This may have therapeutical implications because we have clinically available drugs that target these pathways in gastric cancer.

Identification of 14 Differentially-Expressed Metabolism-Related Genes as Potential Targets of Gastric Cancer by Integrated Proteomics and Transcriptomics

Although research on the metabolism related to gastric cancer (GC) is gradually gaining increasing interest, there are few studies regarding metabolism-related genes in GC. Understanding the characteristic changes of metabolism-related genes at the transcriptional and protein levels in GC will help us to identify new biomarkers and novel therapeutic targets. We harvested six pairs of samples from GC patients and evaluated the differentially expressed proteins using mass spectrometry-based proteomics. RNA sequencing was conducted simultaneously to detect the corresponding expression of mRNAs, and bioinformatics analysis was used to reveal the correlation of significant differentially expressed genes. A total of 57 genes were observed to be dysregulated both in proteomics and transcriptomics. Bioinformatics analysis showed that these differentially expressed genes were significantly associated with regulating metabolic activity. Further, 14 metabolic genes were identified as potential targets for GC patients and were related to immune cell infiltration. Moreover, we found that dysregulation of branched-chain amino acid transaminase 2 (BCAT2), one of the 14 differentially expressed metabolism-related genes, was associated with the overall survival time in GC patients. We believe that this study provides comprehensive information to better understand the mechanism underlying the progression of GC metastasis and explores the potential therapeutic and prognostic metabolism-related targets for GC.

Glycolysis in the progression of pancreatic cancer

Metabolic reprogramming, as a key hallmark of cancers, leads to the malignant behavior of pancreatic cancer, which is closely related to tumor development and progression, as well as the supportive tumor microenvironments. Although cells produce adenosine triphosphate (ATP) from glucose by glycolysis when lacking oxygen, pancreatic cancer cells elicit metabolic conversion from oxide phosphorylation to glycolysis, which is well-known as "Warburg effect". Glycolysis is critical for cancer cells to maintain their robust biosynthesis and energy requirement, and it could promote tumor initiation, invasion, angiogenesis, and metastasis to distant organs. Multiple pathways are involved in the alternation of glycolysis for pancreatic cancer cells, including UHRF1/SIRT4 axis, PRMT5/FBW7/cMyc axis, JWA/AMPK/FOXO3a/FAK axis, KRAS/TP53/TIGAR axis, etc. These signaling pathways play an important role in glycolysis and are potential targets for the treatment of pancreatic cancer. Mutations in glycolytic enzymes (such as LDH, PKM2, and PGK1) also contribute to the early diagnosis and monitoring of pancreatic cancer. In this review, we summarized the recent advances on the mechanisms for glycolysis in pancreatic cancer and the function of glycolysis in the progression of pancreatic cancer, which suggested new targets for cancer diagnosis and treatment.

The Crosstalk Between Signaling Pathways and Cancer Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. Metabolic reprogramming represents an important cancer hallmark in CRC. Reprogramming core metabolic pathways in cancer cells, such as glycolysis, glutaminolysis, oxidative phosphorylation, and lipid metabolism, is essential to increase energy production and biosynthesis of precursors required to support tumor initiation and progression. Accumulating evidence demonstrates that activation of oncogenes and loss of tumor suppressor genes regulate metabolic reprogramming through the downstream signaling pathways. Protein kinases, such as AKT and c-MYC, are the integral components that facilitate the crosstalk between signaling pathways and metabolic pathways in CRC. This review provides an insight into the crosstalk between signaling pathways and metabolic reprogramming in CRC. Targeting CRC metabolism could open a new avenue for developing CRC therapy by discovering metabolic inhibitors and repurposing protein kinase inhibitors/monoclonal antibodies.

Nanoparticle-Encapsulated Camptothecin: Epigenetic Modulation in DNA Repair Mechanisms in Colon Cancer Cells

Molecular crosstalk between the cellular epigenome and genome converge as a synergistic driver of oncogenic transformations. Besides other pathways, epigenetic regulatory circuits exert their effect towards cancer progression through the induction of DNA repair deficiencies. We explored this mechanism using a camptothecin encapsulated in β-cyclodextrin-EDTA-Fe3O4 nanoparticles (CPT-CEF)-treated HT29 cells model. We previously demonstrated that CPT-CEF treatment of HT29 cells effectively induces apoptosis and cell cycle arrest, stalling cancer progression. A comparative transcriptome analysis of CPT-CEF-treated versus untreated HT29 cells indicated that genes controlling mismatch repair, base excision repair, and homologues recombination were downregulated in these cancer cells. Our study demonstrated that treatment with CPT-CEF alleviated this repression. We observed that CPT-CEF exerts its effect by possibly affecting the DNA repair mechanism through epigenetic modulation involving genes of HMGB1, APEX1, and POLE3. Hence, we propose that CPT-CEF could be a DNA repair modulator that harnesses the cell's epigenomic plasticity to amend DNA repair deficiencies in cancer cells.

Tumor pyruvate kinase M2 modulators: a comprehensive account of activators and inhibitors as anticancer agents

Pyruvate kinase M2 (PKM2) catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate. It plays a central role in the metabolic reprogramming of cancer cells and is expressed in most human tumors. It is essential in indiscriminate proliferation, survival, and tackling apoptosis in cancer cells. This positions PKM2 as a hot target in cancer therapy. Despite its well-known structure and several reported modulators targeting PKM2 as activators or inhibitors, a comprehensive review focusing on such modulators is lacking. Herein we summarize modulators of PKM2, the assays used to detect their potential, the preferable tense (T) and relaxed (R) states in which the enzyme resides, lacunae in existing modulators, and several strategies that may lead to effective anticancer drug development targeting PKM2.

Gastric Cancer Stem Cells: A Glimpse on Metabolic Reprogramming

Gastric cancer (GC) is one of the most widespread causes of cancer-related death worldwide. Recently, emerging implied that gastric cancer stem cells (GCSCs) play an important role in the initiation and progression of GC. This subpopulation comprises cells with several features, such as self-renewal capability, high proliferating rate, and ability to modify their metabolic program, which allow them to resist current anticancer therapies. Metabolic pathway intermediates play a pivotal role in regulating cell differentiation both in tumorigenesis and during normal development. Thus, the dysregulation of both anabolic and catabolic pathways constitutes a significant opportunity to target GCSCs in order to eradicate the tumor progression. In this review, we discuss the current knowledge about metabolic phenotype that supports GCSC proliferation and we overview the compounds that selectively target metabolic intermediates of CSCs that can be used as a strategy in cancer therapy.

Rabeprazole suppresses cell proliferation in gastric epithelial cells by targeting STAT3-mediated glycolysis

The dysregulation of glycolysis leads to serials of disease. Rabeprazole is a representative of proton pump inhibitors and widely used in anti-ulcer treatment. However, the function of Rabeprazole on glycolysis in gastric epithelial cells remained to be identified. In this study, 30（Helicobacter pylori）H. pylori-negative cases and 26H. pylori-positive cases treated with Rabeprazole were recruited. The qPCR and Western blotting results showed that Rabeprazole suppressed cell proliferation by inhibition of HK2-mediated glycolysis in BGC823 cells, leading to decrease glucose uptake and lactate production in a dose-dependent way. Furthermore, the phosphorylation of signal transducer and activator of transcription 3 (STAT3) was drastically reduced in response to Rabeprazole stimulation, leading to attenuate STAT3 nuclear translocation. Luciferase and Chromatin immunoprecipitation (ChIP) analysis showed that Rabeprazole treatment led to a significant inhibition of the binding of STAT3 to the promoter of the HK2 gene, repressing transcriptional activation of HK2. Moreover, the ectopic expression of STAT3 in BGC823 cells resulted in recovery of HK2 transactivation and cell proliferation in Rabeprazole-treated cells. Most importantly, HK2 expression was significantly increased in H. pylori-infected gastric mucosa. These findings suggested that Rabeprazole inhibited cell proliferation by targeting STAT3/HK2 signaling-mediated glucose metabolism in gastric epithelial cells. Therefore, targeting HK2 is an alternative strategy in improving the treatment of patients with H. pylori infection.

Discovery of Functional Alternatively Spliced PKM Transcripts in Human Cancers

Simple Summary

Pyruvate kinase muscle type (PKM) is a key enzyme in glycolysis and is a mediator of the Warburg effect in tumors. The association of PKM with survival of cancer patients is controversial. In this study, we investigated the associations of the alternatively spliced transcripts of PKM with cancer patients’ survival outcomes and explained the conflicts in previous studies. We discovered three poorly studied alternatively spliced PKM transcripts that exhibited opposite prognostic indications in different human cancers based on integrative systems analysis. We also detected their protein products and explored their potential biological functions based on in-vitro experiments. Our analysis demonstrated that alternatively spliced transcripts of not only PKM but also other genes should be considered in cancer studies, since it may enable the discovery and targeting of the right protein product for development of the efficient treatment strategies.

Abstract

Pyruvate kinase muscle type (PKM) is a key enzyme in glycolysis and plays an important oncological role in cancer. However, the association of PKM expression and the survival outcome of patients with different cancers is controversial. We employed systems biology methods to reveal prognostic value and potential biological functions of PKM transcripts in different human cancers. Protein products of transcripts were shown and detected by western blot and mass spectrometry analysis. We focused on different transcripts of PKM and investigated the associations between their mRNA expression and the clinical survival of the patients in 25 different cancers. We find that the transcripts encoding PKM2 and three previously unstudied transcripts, namely ENST00000389093, ENST00000568883, and ENST00000561609, exhibited opposite prognostic indications in different cancers. Moreover, we validated the prognostic effect of these transcripts in an independent kidney cancer cohort. Finally, we revealed that ENST00000389093 and ENST00000568883 possess pyruvate kinase enzymatic activity and may have functional roles in metabolism, cell invasion, and hypoxia response in cancer cells. Our study provided a potential explanation to the controversial prognostic indication of PKM, and could invoke future studies focusing on revealing the biological and oncological roles of these alternative spliced variants of PKM.

Pyruvate Kinase M2 Knockdown Suppresses Migration, Invasion, and Epithelial-Mesenchymal Transition of Gastric Carcinoma via Hypoxia-Inducible Factor Alpha/B-Cell Lymphoma 6 Pathway

Gastric carcinoma is a common malignant cancer. Pyruvate kinase M2 (PKM2) is highly expressed in cancers, including gastric carcinoma. However, its function and molecular mechanism in gastric carcinoma remains unclear. Here, we aimed to explore the function and the underlying mechanism of PKM2 on malignant phenotypes in gastric carcinoma. In this study, the mRNA levels and protein levels of PKM2 in gastric carcinoma cell lines and normal gastric mucosa epithelial cell lines were detected using quantitative real-time PCR and western blot, respectively. PKM2 was downregulated by siRNA transfection. HIF-1α or BCL-6 was upregulated by corresponding overexpression plasmid. Cell viability was detected using CCK-8 assay. Cell invasion and migration were determined using transwell assay. Higher expression of PKM2 was observed in human gastric carcinoma cell lines MKN-45 and SGC-7901 than in the normal gastric mucosa epithelial cell line GES-1. PKM2 knockdown suppressed cancer cell invasion and migration and inhibited the epithelial-mesenchymal transition (EMT) phenotype by inhibiting E-cadherin and promoting vimentin and N-cadherin expression. Also, we observed that PKM2 knockdown suppressed the hypoxia-inducible factor alpha (HIF-1α) and B-cell lymphoma 6 (BCL-6) signaling pathway. HIF-1α overexpression reversed the function of PKM2 silencing on cell invasion, migration, EMT, and BCL-6 expression. BCL-6 overexpression also reversed the function of PKM2 silencing on cell invasion, migration, and EMT but did not affect HIF-1α expression. Taken together, data from our study suggest that PKM2 knockdown impeded cell migration, invasion, and EMT of gastric carcinoma cells via the HIF-1α/BCL-6 pathway.

Alternative Splicing: Expanding the Landscape of Cancer Biomarkers and Therapeutics

Alternative splicing (AS) is a critical post-transcriptional regulatory mechanism used by more than 95% of transcribed human genes and responsible for structural transcript variation and proteome diversity. In the past decade, genome-wide transcriptome sequencing has revealed that AS is tightly regulated in a tissue- and developmental stage-specific manner, and also frequently dysregulated in multiple human cancer types. It is currently recognized that splicing defects, including genetic alterations in the spliced gene, altered expression of both core components or regulators of the precursor messenger RNA (pre-mRNA) splicing machinery, or both, are major drivers of tumorigenesis. Hence, in this review we provide an overview of our current understanding of splicing alterations in cancer, and emphasize the need to further explore the cancer-specific splicing programs in order to obtain new insights in oncology. Furthermore, we also discuss the recent advances in the identification of dysregulated splicing signatures on a genome-wide scale and their potential use as biomarkers. Finally, we highlight the therapeutic opportunities arising from dysregulated splicing and summarize the current approaches to therapeutically target AS in cancer.

Cutting off the fuel supply to calcium pumps in pancreatic cancer cells: role of pyruvate kinase-M2 (PKM2)

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has poor survival and treatment options. PDAC cells shift their metabolism towards glycolysis, which fuels the plasma membrane calcium pump (PMCA), thereby preventing Ca2+-dependent cell death. The ATP-generating pyruvate kinase-M2 (PKM2) is oncogenic and overexpressed in PDAC. This study investigated the PKM2-derived ATP supply to the PMCA as a potential therapeutic locus.

METHODS

PDAC cell growth, migration and death were assessed by using sulforhodamine-B/tetrazolium-based assays, gap closure assay and poly-ADP ribose polymerase (PARP1) cleavage, respectively. Cellular ATP and metabolism were assessed using luciferase/fluorescent-based assays and the Seahorse XFe96 analyzer, respectively. Cell surface biotinylation identified membrane-associated proteins. Fura-2 imaging was used to assess cytosolic Ca2+ overload and in situ Ca2+ clearance. PKM2 knockdown was achieved using siRNA.

RESULTS

The PKM2 inhibitor (shikonin) reduced PDAC cell proliferation, cell migration and induced cell death. This was due to inhibition of glycolysis, ATP depletion, inhibition of PMCA and cytotoxic Ca2+ overload. PKM2 associates with plasma membrane proteins providing a privileged ATP supply to the PMCA. PKM2 knockdown reduced PMCA activity and reduced the sensitivity of shikonin-induced cell death.

CONCLUSIONS

Cutting off the PKM2-derived ATP supply to the PMCA represents a novel therapeutic strategy for the treatment of PDAC.

Overexpressed miR-122-5p Promotes Cell Viability, Proliferation, Migration And Glycolysis Of Renal Cancer By Negatively Regulating PKM2

Objective

Renal cancer is one of the most deadly urological malignancies. Currently, there is still a lack of effective treatment. Our purpose was to explore the mechanisms of miR-122-5p in renal cancer.

Methods

The expression levels of miR-122-5p and pyruvate kinase M2 (PKM2) in renal cancer cells were detected by RT-qPCR and Western blot analyses, respectively. Then, we measured the cell viability after knockdown of miR-122-5p and PKM2 using CCK-8 assay. Moreover, flow cytometry was used to investigate cell cycle and apoptosis of renal cancer cells. The cell migration of renal cancer cells transfected by miR-122-5p inhibitor and siPKM2 was then detected by wound healing assay. Furthermore, glucose consumption and lactate production were measured. Autophagy-related protein LCII/I was detected by Western blot.

Results

MiR-122-5p was upregulated in renal cancer cells compared to HK2 cells, especially in 786-O cells. We found that silencing miR-122-5p promoted PKM2 expression in 786-O cells. After transfection of siPKM2 or miR-122-5p inhibitor, the cell viability of 786-O cells was significantly reduced. Furthermore, the G1 phase of 786-O cells was significantly blocked, and the S phase was significantly increased. In addition, knockdown of miR-122-5p or PKM2 promoted renal cancer cell apoptosis and inhibited cell migration. Glucose consumption of 786-O cells was significantly increased after transfection by siPKM2. Silencing miR-122-5p significantly promoted the expression levels of LCII/I.

Conclusion

Our findings revealed that overexpressed miR-122-5p promotes renal cancer cell viability, proliferation, migration, glycolysis and autophagy by negatively regulating PKM2, which provide a new insight for the development of renal cancer therapy.

Antitumor activity of SR splicing-factor 5 knockdown by downregulating pyruvate kinase M2 in non-small cell lung cancer cells

SR splicing-factors (SRSFs) play a vital role in carcinogenesis. SRSF5 was demonstrated to be upregulated in lung cancer and identified as a novel prognostic indicator for small-cell lung cancer. However, the role of SRSF5 in the pathogenesis of non-small cell lung cancer (NSCLC) and the molecular mechanism involved are still undefined. The expression of SRSF5 in NSCLC cells was detected by quantitative real-time polymerase chain reaction and Western blot analysis. The proliferation of cells was evaluated by cell counting kit-8 and BrdU assays. Apoptosis was assessed by flow cytometry and Western blot analysis of apoptosis-associated proteins including B-cell lymphoma 2 (Bcl-2), Bax, and cytochrome C (Cyt C). Glycolysis was detected by determining glucose consumption, lactate production, and pyruvate kinase M2 (PKM2) expression. We found that SRSF5 messenger RNA and protein levels were elevated in NSCLC cells. SRSF5 knockdown inhibited the proliferation and Ki67 expression in NSCLC cells. SRSF5 silencing increased the apoptotic rate, upregulated Bax and Cyt C, and decreased Bcl-2 level in NSCLC cells. Moreover, Knockdown of SRSF5 repressed glycolysis in NSCLC cells via reducing PKM2 expression. Enhanced glycolysis by PKM2 overexpression attenuated the effects of SRSF5 silencing on NSCLC cell proliferation and apoptosis. Overall, knockdown of SRSF5 inhibited proliferative ability and induced apoptosis by suppressing PKM2 expression in NSCLC cells.

Metabolic reprogramming results in abnormal glycolysis in gastric cancer: a review

The Warburg effect in tumor cells involves the uptake of high levels of glucose, enhanced glycolysis, and the metabolism of pyruvate to lactic acid rather than oxidative phos-phorylation to generate energy under aerobic conditions. This effect is closely related to the occurrence, invasion, metastasis, drug resistance, and poor prognosis of gastric cancer (GC). Current research has further demonstrated that the Warburg effect in GC cells is not only mediated by the glycolysis pathway, but also includes roles for mitochondria, noncoding RNAs, and other proteins that do not directly regulate metabolism. As a result, changes in the glycolysis pathway not only lead to abnormal glucose metabolism, but they also affect mitochondrial functions, cellular processes such as apoptosis and cell cycle regulation, and the metabolism of lipids and amino acids. In this review, we discuss metabolic reprogramming in GC based on glycolysis, a possible link between glucose metabolism, lipid metabolism, and amino acid metabolism, and we clarify the role of mitochondria. We also examine recent studies of metabolic inhibitors in GC.

Alternative-splicing defects in cancer: Splicing regulators and their downstream targets, guiding the way to novel cancer therapeutics

Defects in alternative splicing are frequently found in human tumors and result either from mutations in splicing-regulatory elements of specific cancer genes or from changes in the regulatory splicing machinery. RNA splicing regulators have emerged as a new class of oncoproteins and tumor suppressors, and contribute to disease progression by modulating RNA isoforms involved in the hallmark cancer pathways. Thus, dysregulation of alternative RNA splicing is fundamental to cancer and provides a potentially rich source of novel therapeutic targets. Here, we review the alterations in splicing regulatory factors detected in human tumors, as well as the resulting alternatively spliced isoforms that impact cancer hallmarks, and discuss how they contribute to disease pathogenesis. RNA splicing is a highly regulated process and, as such, the regulators are themselves tightly regulated. Differential transcriptional and posttranscriptional regulation of splicing factors modulates their levels and activities in tumor cells. Furthermore, the composition of the tumor microenvironment can also influence which isoforms are expressed in a given cell type and impact drug responses. Finally, we summarize current efforts in targeting alternative splicing, including global splicing inhibition using small molecules blocking the spliceosome or splicing-factor-modifying enzymes, as well as splice-switching RNA-based therapeutics to modulate cancer-specific splicing isoforms. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.

MicroRNA-129-5p Regulates Glycolysis and Cell Proliferation by Targeting the Glucose Transporter SLC2A3 in Gastric Cancer Cells

Tumor cells increase their glucose consumption through aerobic glycolysis to manufacture the necessary biomass required for proliferation, commonly known as the Warburg effect. Accumulating evidences suggest that microRNAs (miRNAs) interact with their target genes and contribute to metabolic reprogramming in cancer cells. By integrating high-throughput screening data and the existing miRNA expression datasets, we explored the roles of candidate glycometabolism-regulating miRNAs in gastric cancer (GC). Subsequent investigation of the characterized miRNAs indicated that miR-129-5p inhibits glucose metabolism in GC cells. miRNA-129-5p directly targets the 3′-UTR of SLC2A3, thereby suppressing glucose consumption, lactate production, cellular ATP levels, and glucose uptake of GC cells. In addition, the PI3K-Akt and MAPK signaling pathways are involved in the effects of the miR-129-5p/SLC2A3 axis, regulating GC glucose metabolism and growth. These results reveal a novel role of the miR-129-5p/SLC2A3 axis in reprogramming the glycometabolism process in GC cells and indicate a potential therapeutic target for the treatment of this disease.

Knockdown of UCA1 inhibits viability and glycolysis by suppressing PKM2 expression through the mTOR pathway in non-small cell lung cancer cells

LncRNA urothelial carcinoma associated 1 (UCA1) was reported to be upregulated in non-small cell lung cancer (NSCLC) tissues and contributed to NSCLC progression. Additionally, it has been proposed that the oncogenic role of UCA1 may be related to glucose metabolism in bladder cancer. However, whether and how UCA1 regulates glucose metabolism in the progression of NSCLC remains unknown. Our results showed that knockdown of UCA1 inhibited the viability of NSCLC cells. UCA1 silencing suppressed glycolysis of NSCLC cells by reducing the glucose consumption and lactate production. Additionally, knockdown of UCA1 suppressed PKM2 expression and the mTOR pathway in NSCLC cells. Mechanistically, PKM2 knockdown suppressed the effects of UCA1 on viability and glycolysis of NSCLC cells and inhibition of the mTOR pathway suppressed the effects of UCA1 on viability, glycolysis, and PKM2 expression in NSCLC cells. In conclusion, knockdown of UCA1 inhibited viability and glycolysis by suppressing PKM2 expression maybe through the mTOR pathway in NSCLC cells, providing a novel insight into the molecular mechanism of UCA1 involved in the regulation of glucose metabolism in NSCLC cells.

Effects of shRNA-Mediated Silencing of PKM2 Gene on Aerobic Glycolysis, Cell Migration, Cell Invasion, and Apoptosis in Colorectal Cancer Cells

This study aims to explore the effects of shRNA-mediated silencing on Pyruvate kinase type M2 (PKM2) gene during aerobic glycolysis in colorectal cancer (CRC) cells. CRC tissues and adjacent normal tissues were obtained from 136 patients diagnosed with qRT-PCR, Western blotting, and immunohistochemistry (IHC) were performed to detect mRNA and protein expressions of PKM2. CRC cells were divided into a blank, vector, and PKM2-shRNA groups. Hexokinase (HK) and PKM2 activity were both determined by glucose-6-phosphate dehydrogenase (G-6-PD) coupled colorimetric assay and enzyme coupling rate method. The extracellular lactate concentration was measured by ultraviolet spectrophotometer and caspase activity was measured using spectrophotometry. The proliferation, cell cycle, apoptosis, invasion, and migration of CRC cells were detected by cell counting kit-8 (CCK-8) assay, flow cytometry, transwell assay, and scratch test. Three groups of nude mice were injected with 0.2 mL single-cell suspension from the blank, vector, and PKM2-shRNA groups, respectively. PKM2 protein content in CRC tissues was higher than that in adjacent normal tissues. Results showed that the PKM2-shRNA group exhibited significantly lower mRNA and protein expressions of PKM2, decreased PKM2 activity, reduced lactate metabolism level, increased cell apoptosis rate, elevated caspase-3 and caspase-9 activity, weakened proliferation, and a reduction in cell invasion and migration ability compared to the vector and blank groups. The optical density (OD) value was lower in the PKM2-shRNA group than in the blank and vector groups. These findings indicate that shRNA-mediated silencing of PKM2 gene promotes apoptosis and inhibits aerobic glycolysis, proliferation, migration, and invasion in CRC cells. J. Cell. Biochem. 118: 4792-4803, 2017. © 2017 Wiley Periodicals, Inc.

Pyruvate kinase isozyme M2 and glutaminase might be promising molecular targets for the treatment of gastric cancer

The aim of this study was to analyze the significance of glucose metabolism-related enzymes in the proliferation of gastric cancer under hypoxia. Four hypoxia-resistant gastric cancer cell lines and four parent cell lines were used. Reverse transcription-PCR was used to evaluate the mRNA expression levels of the following metabolism-related enzymes: pyruvate kinase isozyme M2 (PKM2), glutaminase (GLS), enolase 1 (ENO1), glucose-6-phosphate dehydrogenase (G6PDH), and PKM1. The effects of these enzymes on the proliferation of gastric cancer cells were examined using siRNAs, shikonin as a PKM2 inhibitor, or BPTES as a GLS inhibitor, in vitro and in vivo. Levels of both PKM2 and GLS mRNA were significantly high in all hypoxia-resistant cell lines, compared with those of their parent cells. Knockdown of PKM2 and GLS significantly decreased the proliferation of all hypoxia-resistant cells. The combination of siPKM2 and siGLS significantly decreased proliferation compared with treatment by siPKM2 or siGLS alone. The knockdown of ENO1, G6PDH, or PKM1 did not decrease the proliferation of all hypoxia-resistant cells. Combination treatment using shikonin and BPTES inhibited the proliferation of all hypoxia-resistant cancer cells more than that by either agent alone. The in vivo study indicated that the tumor size treated by the combination of shikonin and BPTES was significantly smaller than that of vehicle-treated group. These findings suggested that PKM2 and GLS might play important roles in the proliferation of hypoxic gastric cancer cells. A combination of PKM2 and GLS inhibitors could be therapeutically promising for the treatment of gastric cancer.

Enhanced expression of the M2 isoform of pyruvate kinase is involved in gastric cancer development by regulating cancer-specific metabolism

Recent studies have indicated that increased expression of the M2 isoform of pyruvate kinase (PKM2) is involved in glycolysis and tumor development. However, little is known about the role of PKM2 in gastric cancer (GC). Therefore, we examined the expression and function of PKM2 in human GC. We evaluated PKM1 and PKM2 expression by quantitative RT-PCR in gastric tissues from 10 patients who underwent gastric endoscopic submucosal dissection, 80 patients who underwent gastrectomy, and seven healthy volunteers, and analyzed the correlation with clinicopathological variables. To assess the function of PKM2, we generated PKM2-knockdown GC cells, and investigated the phenotypic changes. Furthermore, we examined the induction of PKM2 expression by cytotoxin-associated gene A (CagA), a pathogenic factor of Helicobacter pylori, using CagA-inducible GC cells. We found that PKM2 was predominantly expressed not only in GC lesions but also in the normal gastric regions of GC patients and in the gastric mucosa of healthy volunteers. The PKM2 expression was significantly higher in carcinoma compared to non-cancerous tissue and was associated with venous invasion. Knockdown of PKM2 in GC cells caused significant decreases in cellular proliferation, migration, anchorage-independent growth, and sphere formation in vitro, and in tumor growth and liver metastasis in vivo. The serine concentration-dependent cell proliferation was also inhibited by PKM2 silencing. Furthermore, we found that PKM2 expression was upregulated by CagA by way of the Erk pathway. These results suggested that enhanced PKM2 expression plays a pivotal role in the carcinogenesis and development of GC in part by regulating cancer-specific metabolism.