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Tumors have long been known to rewire their metabolism to endorse their proliferation, growth, survival, and invasiveness. One of the common characteristics of these alterations is the enhanced glucose uptake and its subsequent transformation into lactic acid by means of glycolysis, regardless the availability of oxygen or the mitochondria effectiveness. This phenomenon is called the "Warburg effect", which has turned into a century of age now, since its first disclosure by German physiologist Otto Heinrich Warburg. Since then, this peculiar metabolic switch in tumors has been addressed by extensive studies covering several areas of research. In this historical perspective, we aim at illustrating the evolution of these studies over time and their implication in various fields of science.

Cancer-related metabolic features are in part maintained by hexokinase 2 upregulation, which leads to high levels of glucose-6-phosphate (G6P) and is needed to provide energy and biomass to support rapid proliferation. Using a humanized model of the yeast Saccharomyces cerevisiae, we explored how human hexokinase 2 (HK2) behaves under different nutritional conditions. At high glucose levels, yeast presents aerobic glycolysis through a regulatory mechanism known as catabolic repression, which exerts a metabolic adaptation like the Warburg effect. At high glucose concentrations, HK2 did not translocate into the nucleus and was not able to shift the metabolism toward a highly glycolytic state, in contrast to the effect of yeast hexokinase 2 (Hxk2), which is a crucial protein for the control of aerobic glycolysis in S. cerevisiae. During the stationary phase, when glucose is exhausted, Hxk2 is shuttled out of the nucleus, ceasing catabolic repression. Cells harvested at this condition display low glucose consumption rates. However, glucose-starved cells expressing HK2 had an increased capacity to consume glucose. In those cells, HK2 localized to mitochondria, becoming insensitive to G6P inhibition. We also found that the sugar trehalose-6-phosphate (T6P) is a human HK2 inhibitor, like yeast Hxk2, but was not able to inhibit human HK1, the isoform that is ubiquitously expressed in almost all mammalian tissues. In contrast to G6P, T6P inhibited HK2 even when HK2 was associated with mitochondria. The binding of HK2 to mitochondria is crucial for cancer survival and proliferation. T6P was able to reduce the cell viability of tumor cells, although its toxicity was not impressive. This was expected as cell absorption of phosphorylated sugars is low, which might be counteracted using nanotechnology. Altogether, these data suggest that T6P may offer a new paradigm for cancer treatment based on specific inhibition of HK2.

Background and aims Renal fibrosis is the common outcome in all progressive forms of chronic kidney disease. Unfortunately, the pathogenesis of renal fibrosis remains largely unexplored, among which metabolic reprogramming plays an extremely crucial role in the evolution of renal fibrosis. Ceria nanoparticles (CeNP-PEG) with strong ROS scavenging and anti-inflammatory activities have been applied for mitochondrial oxidative stress and inflammatory diseases. The present study aims to determine whether CeNP-PEG has therapeutic value for renal fibrosis. Methods The unilateral ureteral obstructive fibrosis model was used to assess the therapeutic effects in vivo. Transforming growth factor beta1-induced epithelial-to-mesenchymal transition in HK-2 cells was used as the in vitro cell model. The seahorse bioscience X96 extracellular flux analyzer was used to measure the oxygen consumption rate and extracellular acidification rate. Results In the present study, CeNP-PEG treatment significantly ameliorated renal fibrosis by increased E-cadherin protein expression, and decreased α-SMA, Vimentin and Fibronectin expression both in vitro and in vivo. Additionally, CeNP-PEG significantly reduced the ROS formation and improved the levels of mitochondrial ATP. The seahorse analyzer assay demonstrated that the extracellular acidification rate markedly decreased, whereas the oxygen consumption rate markedly increased, in the presence of CeNP-PEG. Furthermore, the mitochondrial membrane potential markedly enhanced, hexokinase 1 and hexokinase 2 expression significantly decreased after treatment with CeNP-PEG. Conclusions CeNP-PEG can block the dysregulated metabolic status and exert protective function on renal fibrosis. This may provide another therapeutic option for renal fibrosis. Graphical Abstract

Osteosarcoma (OS) is a malignant bone tumor among adolescents and young adults. IRF7 belongs to the transcription factor family of interferon regulatory factors (IRFs) and has previously been described to function as a tumor suppressor in multiple cancer types. However, the biological functions and cellular mechanism of IRF7 in OS remain elusive. In this study, by quantitative real-time PCR (qRT-PCR) and western blotting, we found that IRF7 was downregulated in OS, and the higher expression of IRF7 was correlated with a better survival prognosis. Moreover, loss-of-function and gain-of-function studies have proved the critical functions of IRF7 in suppressing aerobic glycolysis of osteosarcoma cells as evidenced by glucose uptake, lactate production, extracellular acidification rate, and oxygen consumption rate. Mechanistically, IRF7 inhibited the expression of key glycolytic gene PKM2 via direct transcriptional regulation. Moreover, the in vitro and in vivo tumor-suppressive roles of IRF7 were uncovered in OS and these effects were largely glycolysis-dependent. Therefore, our study unveils a previous unprecedented role of IRF7 in glucose metabolism reprogram and suggests that IRF7 might serve as a potential therapeutic target for patients with OS.

Background Osteosarcoma (OS) is a common primary bone malignancy. Long noncoding RNA HCG18 is known to play an important role in a variety of cancers. However, its role in OS and relevant molecular mechanisms are unclear. Methods Real-time quantitative PCR was performed to determine the expression of target genes. Function experiments showed the effects of HCG18 and miR-365a-3p on OS cell growth. Results HCG18 expression was increased in OS cell lines. Moreover, in vitro and in vivo experiments demonstrated that HCG18 knockdown inhibited OS cell proliferation. Mechanistically, HCG18 was defined as a competing endogenous RNA by sponging miR-365a-3p, thus elevating phosphoglycerate kinase 1 (PGK1) expression by directly targeting its 3ʹUTR to increase aerobic glycolysis. Conclusion HCG18 promoted OS cell proliferation via enhancing aerobic glycolysis by regulating the miR-365a-3p/PGK1 axis. Therefore, HCG18 may be a potential target for OS treatment.

Autophagy allows cells to temporarily tolerate energy stress by replenishing critical metabolites through self-digestion, thereby attenuating the cytotoxic effects of anticancer drugs that target tumor metabolism. Autophagy defects could therefore mark a metabolically vulnerable cancer state and open a therapeutic window. While mutations of autophagy genes (ATGs) are notably rare in cancer, haploinsufficiency network analyses across many cancers have shown that the autophagy pathway is frequently hit by somatic copy number losses of ATGs like MAP1LC3B/ATG8F (LC3), BECN1/ATG6 (Beclin-1), and ATG10. Here, we used CRISPR/Cas9 technology to delete increasing numbers of copies of one or more of these ATGs in non-small cell lung cancer cells and examined the effects on sensitivity to compounds targeting aerobic glycolysis, a hallmark of cancer metabolism. Whereas complete knock-out of one ATG blocked autophagy and led to profound metabolic vulnerability, this was not the case for combinations of different non-homozygous deletions. In cancer patients, the effect of ATG copy number loss was blunted at the protein level and did not lead to accumulation of p62 as a sign of reduced autophagic flux. Thus, the autophagy pathway is shown to be markedly robust and resilient, even with concomitant copy number loss of key autophagy genes.

In recent researches, circular RNAs (circRNAs) have been shown to exert critical functions in osteosarcoma biology. Nevertheless, the contribution of circRNAs to osteosarcoma remains largely unclear. Results indicated that expression of circATRNL1 was higher in osteosarcoma tissues and cells. The high-expression of circATRNL1 was significantly correlated with aggressive features and acted as an independent risk factor for osteosarcoma patients’ overall survival. Functionally, our findings demonstrate that circATRNL1 promotes the osteosarcoma aerobic glycolysis in vitro. Mechanistically, circATRNL1 up-regulated the expression level of LDHA, which was also targeted by miR-409-3p. Therefore, circATRNL1 exerted the accelerative roles of osteosarcoma aerobic glycolysis through miR-409-3p/LDHA axis. In conclusion, circATRNL1 promoted osteosarcoma progression by enhancing glycolysis via circATRNL1/miR-409-3p/LDHA axis, which may inspire a novel therapeutic target for osteosarcoma.

Background Increased expression of the transcription factor Forkhead box M1 (FOXM1) has been reported to play an important role in the progression and development of multiple tumors, but the molecular mechanisms that regulate FOXM1 expression remain unknown, and the role of FOXM1 in aerobic glycolysis is still not clear. Methods The expression of FOXM1 and NADPH oxidase 4 (NOX4) in normal brain tissues and glioma was detected in data from the TCGA database and in our specimens. The effect of NOX4 on the expression of FOXM1 was determined by Western blot, qPCR, reactive oxygen species (ROS) production assays, and luciferase assays. The functions of NOX4 and FOXM1 in aerobic glycolysis in glioblastoma cells were determined by a series of experiments, such as Western blot, extracellular acidification rate (ECAR), lactate production, and intracellular ATP level assays. A xenograft mouse model was established to test our findings in vivo. Results The expression of FOXM1 and NOX4 was increased in glioma specimens compared with normal brain tissues and correlated with poor clinical outcomes. Aberrant mitochondrial reactive oxygen species (ROS) generation of NOX4 induced FOXM1 expression. Mechanistic studies demonstrated that NOX4-derived MitoROS exert their regulatory role on FOXM1 by mediating hypoxia-inducible factor 1α (HIF-1α) stabilization. Further research showed that NOX4-derived MitoROS-induced HIF-1α directly activates the transcription of FOXM1 and results in increased FOXM1 expression. Overexpression of NOX4 or FOXM1 promoted aerobic glycolysis, whereas knockdown of NOX4 or FOXM1 significantly suppressed aerobic glycolysis, in glioblastoma cells. NOX4-induced aerobic glycolysis was dependent on elevated FOXM1 expression, as FOXM1 knockdown abolished NOX4-induced aerobic glycolysis in glioblastoma cells both in vitro and in vivo. Conclusion Increased expression of FOXM1 induced by NOX4-derived MitoROS plays a pivotal role in aerobic glycolysis, and our findings suggest that inhibition of NOX4-FOXM1 signaling may present a potential therapeutic target for glioblastoma treatment.

Long non-coding RNAs (lncRNAs) have critical functions in tumorigenesis and progression of colorectal cancer (CRC). The role of lncRNA COL4A2-AS1 (COL4A2-AS1) lacks system investigation. The current study comprehensively analyzed the expression, biological functions, and mechanism of COL4A2-AS1 in CRC through performing real-time quantitative PCR (RT-qPCR), Western blot, cell transfection, cell colony assay, MTT assay, flow cytometry and dual-luciferase reporter system assays. A xenograft model of CRC was constructed to further verify the function of COL4A2-AS1 in CRC progression in vivo. The data revealed an upregulated expression of COL4A2-AS1 in CRC tissues and cell lines than paired adjacent tissues and normal cell line. Silencing COL4A2-AS1 inhibited proliferation, aerobic glycolysis, and promoted apoptosis of CRC cells in vivo and in vitro. However, overexpression of COL4A2-AS1 significantly promoted CRC cell proliferation and aerobic glycolysis. In CRC cells, miR-20b-5p was sponged by COL4A2-AS1 and hypoxia-inducible factor 1 alpha subunit (HIF1A). Restoration of HIF1A expression reversed the inhibitory effects of silencing COL4A2-AS1 on aerobic glycolysis and proliferation of CRC cells. The current findings showed that COL4A2-AS1 promoted the proliferation, and aerobic glycolysis of CRC cells potentially through modulating the miR-20b-5p/HIF1A axis.

Improving the chemotherapy resistance of temozolomide (TMZ) is of great significance in the treatment of glioblastoma multiforme (GBM). Long non‐coding RNA just proximal to the X‐inactive specific transcript (JPX) has been proven to be involved in cancer progression. However, the intrinsic significance and molecular mechanism by which JPX orchestrates GBM progression and TMZ chemotherapy resistance remain poorly understood. Here, JPX was found to be significantly elevated in GBM tissues and cell lines, and patients with high expressions of JPX showed significantly worse prognoses. Functional experiments revealed its carcinogenic roles in GBM cell proliferation, TMZ chemoresistance, anti‐apoptosis, DNA damage repair, and aerobic glycolysis. Mechanistically, JPX formed a complex with phosphoinositide dependent kinase‐1 (PDK1) messenger RNA (mRNA) and promoted its stability and expression. Furthermore, an RNA immunoprecipitation (RIP) experiment showed that JPX interacted with N6‐methyladenosine (m6A) demethylase FTO alpha‐ketoglutarate dependent dioxygenase (FTO) and enhanced FTO‐mediated PDK1 mRNA demethylation. JPX exerted its GBM‐promotion effects through the FTO/PDK1 axis. Taken together, these findings reveal the key role of JPX in promoting GBM aerobic glycolysis and TMZ chemoresistance in an m6A‐dependent manner. Thus, it comprises a promising novel therapeutic target for GBM chemotherapy., Our findings uncover a key role of just proximal to the X‐inactive specific transcript in promoting glioblastoma multiforme (GBM) aerobic glycolysis and temozolomide chemoresistance in a N6‐methyladenosine (m6A)‐dependent manner, providing a promising novel therapeutic target for GBM chemotherapy.

Background To investigate the value of Dickkopf-related protein 3 (DKK3) on aerobic glycolysis in pancreatic cancer cells, where DKK3-overexpression is used to determine its effects on CD4+ T cells. Methods The BxPC-3-DKK3 cell line was constructed, and peripheral blood mononuclear cell (PBMC) was prepared. After isolated the CD4+ T cells, the lactic acid, glucose uptake ability, cellular viability, proliferation, apoptosis, and markers were detected by PCR and western blot, and the concentrations of multiple cytokines were determined using the ELISA method. Results After co-culture with pancreatic cancer cells overexpressing DKK3, the glucose uptake markedly, proliferation enhanced and apoptosis inhibited in CD4+ T cells. The co-culture model also revealed that DKK3-overexpression promotes the activation and regulates the metabolism and function of CD4+ T cells. Conclusions DKK3 alters the metabolic microenvironment of pancreatic cancer cells and further facilitates the function of CD4+ T cells which suggesting that DKK3 may have a therapeutic potential in pancreatic cancer.

Deregulated metabolism is one of the characteristics of hepatocellular carcinoma. Sex hormone receptor signalling has been involved in the marked gender dimorphism of hepatocellular carcinoma pathogenesis. Oestrogen receptor (ER) has been reported to reduce the incidence of liver cancer. However, it remains unclear how oestrogen and ER regulate metabolic alterations in liver tumour cells. Our previous work revealed that ERα interacted with carbohydrate responsive element binding protein (ChREBP), which is a transcription factor promoting aerobic glycolysis and proliferation of hepatoma cells. Here, the data showed that ERα overexpression with E2 treatment reduced aerobic glycolysis and cell proliferation of hepatoma cells. In addition to modestly down‐regulating ChREBP transcription, ERα promoted ChREBP degradation. ERα co‐immunoprecipitated with both ChREBP‐α and ChREBP‐β, the two known subtypes of ChREBP. Although E2 promoted ERα to translocate to the nucleus, it did not change subcellular localization of ChREBP. In addition to interacting with ChREBP‐β and promoting its degradation, ERα decreased ChREBP‐α–induced ChREBP‐β transcription. Taken together, we confirmed an original role of ERα in suppressing aerobic glycolysis in liver cancer cells and elucidated the mechanism by which ERα and ChREBP‐α together regulated ChREBP‐β expression.

Made available in DSpace on 2021-06-25T12:32:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-05 UT Hlth San Antonio, Dept Cell Syst & Anat, San Antonio, TX 78229 USA Fac Med Sao Jose Rio Preto, Lab Invest Mol Canc, Ave Brigadeiro Faria Lima 5416, BR-15090000 Sao Paulo, Brazil IBB UNESP, Dept Biol Estrutural & Func, Setor Anat, Inst Biociencias, Campus Botucatu, BR-18618689 Sao Paulo, Brazil Natl Univ 14 Cuyo, Med Sci Coll, Pathol Dept, Pharmacol Area, RA-5500 Mendoza, Argentina Fac Med, Dept Morfol & Biol Celular, C Julian Claveria 6, Oviedo 33006, Spain IBB UNESP, Dept Biol Estrutural & Func, Setor Anat, Inst Biociencias, Campus Botucatu, BR-18618689 Sao Paulo, Brazil

Background Reprogrammed glucose metabolism of enhanced Warburg effect (or aerobic glycolysis) is considered as a hallmark of cancer. Long non-coding RNAs (lncRNAs) have been certified to play a crucial role in tumor progression. The current study aims to inquire into the potential regulatory mechanism of long intergenic non-protein coding RNA 242 (LINC00242) on aerobic glycolysis in gastric cancer. Method LINC00242, miR-1-3p and G6PD expression levels in gastric cancer tissues and cells were determined by qRT-PCR. Cell apoptosis or viability were examined by Flow cytometry or MTT assay. Western blot was utilized to investigate G6PD protein expression levels. Immunohistochemical (IHC) and hematoxylin and eosin (H&E) staining were used for histopathological detection. The targeted relationship between LINC00242 or G6PD and miR-1-3p was verified by luciferase reporter gene assay. Nude mouse xenograft was utilized to detect tumor formation in vivo. Result LINC00242 and G6PD was high-expressed in gastric cancer tissues and cells, and LINC00242 is positively correlated with G6PD. Silencing of LINC00242 or G6PD within gastric cancer cells prominently inhibited cell proliferation and aerobic glycolysis in vitro and relieved the tumorigenesis of gastric cancer in vivo. miR-1-3p was predicted to directly target both LINC00242 and G6PD. Overexpression of miR-1-3p suppressed gastric cancer cells proliferation and aerobic glycolysis. LINC00242 competitively combined miR-1-3p, therefore relieving miR-1-3p-mediated suppression on G6PD. Conclusion LINC00242 plays a stimulative role in gastric cancer aerobic glycolysis via regulation of miR-1-3p/ G6PD axis, therefore affecting gastric cancer cell proliferation.

Liver cancer has become the sixth most diagnosed cancer and the fourth leading cause of cancer death worldwide. Hepatocellular carcinoma (HCC) is responsible for up to 75–85% of primary liver cancers, and sorafenib is the first targeted drug for advanced HCC treatment. However, sorafenib resistance is common because of the resultant enhancement of aerobic glycolysis and other molecular mechanisms. Aerobic glycolysis was firstly found in HCC, acts as a hallmark of liver cancer and is responsible for the regulation of proliferation, immune evasion, invasion, metastasis, angiogenesis, and drug resistance in HCC. The three rate-limiting enzymes in the glycolytic pathway, including hexokinase 2 (HK2), phosphofructokinase 1 (PFK1), and pyruvate kinases type M2 (PKM2) play an important role in the regulation of aerobic glycolysis in HCC and can be regulated by many mechanisms, such as the AMPK, PI3K/Akt pathway, HIF-1α, c-Myc and noncoding RNAs. Because of the importance of aerobic glycolysis in the progression of HCC, targeting key factors in its pathway such as the inhibition of HK2, PFK or PKM2, represent potential new therapeutic approaches for the treatment of HCC.

In this study, we investigated the mechanistic role and prognostic significance of the long coding RNA (lncRNA) KCNQ1OT1 in colorectal cancer (CRC). KCNQ1OT1 levels were significantly higher in CRC tissues than adjacent normal colorectal tissues (n=79). High KCNQ1OT1 expression correlated with poorer prognosis in CRC patients. KCNQ1OT1-silenced CRC cells showed reduced proliferation, colony formation, extracellular acidification, and lactate and glucose secretion. This suggests KCNQ1OT1 promotes CRC cell proliferation by increasing aerobic glycolysis. RNA pull-down assays with biotinylated KCNQ1OT1 followed by mass spectrometry analysis showed that KCNQ1OT1 directly binds to hexokinase 2 (HK2). This was confirmed by RNA immunoprecipitation assays using anti-hexokinase 2 antibody. HK2 protein levels were reduced in KCNQ1OT1 knockdown CRC cells, but were restored by treatment with the proteasomal inhibitor MG132. KCNQ1OT1 knockdown CRC cells also showed higher ubiquitinated-HK2 levels, suggesting KCNQ1OT1 enhances aerobic glycolysis by stabilizing HK2. HK2 overexpression in KCNQ1OT1 knockdown CRC cells restored proliferation and aerobic glycolysis. KCNQ1OT1 levels correlated positively with HK2 expression and prognosis in CRC patients. These findings show that KCNQ1OT1 promotes colorectal carcinogenesis by increasing aerobic glycolysis through HK2.

Sorafenib resistance is a major challenge in the therapy for advanced hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of HCC resistance to sorafenib remain unclear. Activator of thyroid and retinoid receptor (ACTR, also known as SRC‐3), overexpressed in HCC patients, plays an important oncogenic role in HCC; however, the link between ACTR and sorafenib resistance in HCC is unknown. Our study demonstrated that ACTR was one of the most upregulated genes in sorafenib‐resistant HCC xenografts. ACTR increases sorafenib resistance through regulation of the Warburg effect. ACTR promotes glycolysis through upregulation of glucose uptake, ATP and lactate production, and reduction of the extracellular acidification and the oxygen consumption rates. Glycolysis regulated by ACTR is vital for the susceptibility of HCC to sorafenib in vitro and in vivo. Mechanistically, ACTR knockout or knockdown decreases the expression of glycolytic enzymes. In HCC patients, ACTR expression is positively correlated with glycolytic gene expression and is associated with poorer outcome. Furthermore, ACTR interacts with the central regulator of the Warburg effect, c‐Myc, and promotes its recruitment to glycolytic gene promoters. Our findings provide new clues regarding the role of ACTR as a prospective sensitizing target for sorafenib therapy in HCC., Sorafenib resistance is a major challenge in the therapy for advanced hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of HCC resistance to sorafenib remain unclear. Here, the authors find that ACTR increases the sorafenib resistance phenotype and suppresses sorafenib‐induced apoptosis through upregulation of the Warburg effect, providing new clues regarding ACTR as a prospective sensitizing target in sorafenib therapy.

Significant enhancement of the glycolysis pathway is a major feature of tumor cells, even in the presence of abundant oxygen; this enhancement is known as the Warburg effect, and also called aerobic glycolysis. The Warburg effect was discovered nearly a hundred years ago, but its specific mechanism remains difficult to explain. DNA methylation is considered to be a potential trigger for the Warburg effect, as the two processes have many overlapping links during tumorigenesis. Based on a widely recognized potential mechanism of the Warburg effect, we here summarized the relationship between DNA methylation and the Warburg effect with regard to cellular energy metabolism factors, such as glycolysis related enzymes, mitochondrial function, glycolysis bypass pathways, the tumor oxygen sensing pathway and abnormal methylation conditions. We believe that clarifying the relationship between these different mechanisms may further help us understand how DNA methylation works on tumorigenesis and provide new opportunities for cancer therapy.

Background Aerobic glycolysis is a hallmark of metabolic reprogramming that contributes to tumor progression. However, the mechanisms regulating expression of glycolytic genes in neuroblastoma (NB), the most common extracranial solid tumor in childhood, still remain elusive. Methods Crucial transcriptional regulators and their downstream glycolytic genes were identified by integrative analysis of a publicly available expression profiling dataset. In vitro and in vivo assays were undertaken to explore the biological effects and underlying mechanisms of transcriptional regulators in NB cells. Survival analysis was performed by using Kaplan-Meier method and log-rank test. Results Hepatocyte nuclear factor 4 alpha (HNF4A) and its derived long noncoding RNA (HNF4A-AS1) promoted aerobic glycolysis and NB progression. Gain- and loss-of-function studies indicated that HNF4A and HNF4A-AS1 facilitated the glycolysis process, glucose uptake, lactate production, and ATP levels of NB cells. Mechanistically, transcription factor HNF4A increased the expression of hexokinase 2 (HK2) and solute carrier family 2 member 1 (SLC2A1), while HNF4A-AS1 bound to heterogeneous nuclear ribonucleoprotein U (hnRNPU) to facilitate its interaction with CCCTC-binding factor (CTCF), resulting in transactivation of CTCF and transcriptional alteration of HNF4A and other genes associated with tumor progression. Administration of a small peptide blocking HNF4A-AS1-hnRNPU interaction or lentivirus-mediated short hairpin RNA targeting HNF4A-AS1 significantly suppressed aerobic glycolysis, tumorigenesis, and aggressiveness of NB cells. In clinical NB cases, high expression of HNF4A-AS1, hnRNPU, CTCF, or HNF4A was associated with poor survival of patients. Conclusions These findings suggest that therapeutic targeting of HNF4A-AS1/hnRNPU/CTCF axis inhibits aerobic glycolysis and NB progression.

Malignant tumors, including colorectal cancer (CRC), usually rely on ATP generation through aerobic glycolysis for both rapid growth and chemotherapy resistance. The M2 isoform of pyruvate kinase (PKM2) has a key role in catalyzing glycolysis, and PKM2 expression varies even within a single tumor. In this study, we confirmed that expression of PKM2 is heterogeneous in CRC cells, namely high in oxaliplatin‐resistant cells but relatively low in sensitive cells, and found that chemoresistant cells had enhanced glycolysis and ATP production. In addition, we report a PKM2‐dependent mechanism through which chemosensitive cells may gradually transform into chemoresistant cells. The circular RNA hsa_circ_0005963 (termed ciRS‐122 in this study), which was determined to be a sponge for the PKM2‐targeting miR‐122, was positively correlated with chemoresistance. In vitro and in vivo studies showed that exosomes from oxaliplatin‐resistant cells delivered ciRS‐122 to sensitive cells, thereby promoting glycolysis and drug resistance through miR‐122 sponging and PKM2 upregulation. Moreover, si‐ciRS‐122 transported by exosomes could suppress glycolysis and reverse resistance to oxaliplatin by regulating the ciRS‐122–miR‐122–PKM2 pathway in vivo. Exosomes derived from chemoresistant CRC cells could transfer ciRS‐122 across cells and promote glycolysis to reduce drug susceptibility in chemosensitive cells. This intercellular signal delivery suggests a potential novel therapeutic target and establishes a foundation for future clinical applications in drug‐resistant CRC., Exosomes from oxaliplatin‐resistant colorectal cancer (CRC) cells transferred ciRS‐122 to oxaliplatin‐sensitive cells, enhancing glycolysis and drug resistance by promoting PKM2 expression. Furthermore, ciRS‐122 targeting through exosome‐delivered small interfering (si)RNA in vivo enhanced the drug response, indicating a novel potential approach for the reversion of oxaliplatin resistance in CRC.

Rationale: Endoplasmic reticulum oxidoreductase 1 alpha (ERO1L) is an endoplasmic reticulum (ER) luminal glycoprotein that has a role in the formation of disulfide bonds of secreted proteins and membrane proteins. Emerging data identify ERO1L as a tumor promoter in a wide spectrum of human malignancies. However, its molecular basis of oncogenic activities remains largely unknown. Methods: Pan-cancer analysis was performed to determine the expression profile and prognostic value of ERO1L in human cancers. The mechanism by which ERO1L promotes tumor growth and glycolysis in pancreatic ductal adenocarcinoma (PDAC) was investigated by cell biological, molecular, and biochemical approaches. Results: ERO1L was highly expressed in PDAC and its precursor pancreatic intraepithelial neoplasia and acts as an independent prognostic factor for patient survival. Hypoxia and ER stress contributed to the overexpression pattern of ERO1L in PDAC. ERO1L knockdown or pharmacological inhibition with EN460 suppressed PDAC cell proliferation in vitro and slowed tumor growth in vivo. Ectopic expression of wild type ERO1L but not its inactive mutant form EROL-C394A promoted tumor growth. Bioinformatics analyses and functional analyses confirmed a regulatory role of ERO1L on the Warburg effect. Notably, inhibition of tumor glycolysis partially abrogated the growth-promoting activity of ERO1L. Mechanistically, ERO1L-mediated ROS generation was essential for its oncogenic activities. In clinical samples, ERO1L expression was correlated with the maximum standard uptake value (SUVmax) in PDAC patients who received 18F-FDG PET/CT imaging preoperatively. Analysis of TCGA cohort revealed a specific glycolysis gene expression signature that is highly correlated with unfolded protein response-related gene signature. Conclusion: Our findings uncover a key function for ERO1L in Warburg metabolism and indicate that targeting this pathway may offer alternative therapeutic strategies for PDAC.

Since triple-negative breast cancer (TNBC) was first defined over a decade ago, increasing studies have focused on its genetic and molecular characteristics. Patients diagnosed with TNBC, compared to those diagnosed with other breast cancer subtypes, have relatively poor outcomes due to high tumor aggressiveness and lack of targeted treatment. Metabolic reprogramming, an emerging hallmark of cancer, is hijacked by TNBC to fulfill bioenergetic and biosynthetic demands; maintain the redox balance; and further promote oncogenic signaling, cell proliferation, and metastasis. Understanding the mechanisms of metabolic remodeling may guide the design of metabolic strategies for the effective intervention of TNBC. Here, we review the metabolic reprogramming of glycolysis, oxidative phosphorylation, amino acid metabolism, lipid metabolism, and other branched pathways in TNBC and explore opportunities for new biomarkers, imaging modalities, and metabolically targeted therapies.

Rationale: Non-small cell lung cancer (NSCLC) is a deadly disease with a hallmark of aberrant metabolism. The mechanism of glycolysis associated lncRNA underlying the aggressive behaviors of NSCLC is poorly understood. Methods: The expression level of AC020978 in NSCLC was measured by quantitative real-time PCR and fluorescence in situ hybridization (FISH) assay. The biological role of AC020978 in cell proliferation and aerobic glycolysis was determined by functional experiments in vitro and in vivo. The transcription of AC020978 was assessed by dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assay. RNA pull-down, mass spectrometry and RNA immunoprecipitation (RIP) assays were used to identify the interaction protein with AC020978. Western blotting, in situ proximity ligation assay (PLA), and co-immunoprecipitation (co-IP) were performed to reveal the potential mechanism of AC020978. Results: The present study indicated that AC020978 was upregulated in NSCLC, significantly correlated with advanced TNM stage and poor clinical outcomes, representing as an independent prognostic predictor. Functional assays revealed AC020978's role in promoting cell growth and metabolic reprogramming. Moreover, AC020978 was an upregulated lncRNA under glucose starvation as well as hypoxia conditions, and directly transactivated by HIF-1α. Mechanistic investigations identified that AC020978 directly interacted with Pyruvate kinase isozymes M2 (PKM2) and enhanced PKM2 protein stability. Besides, this study uncovered that AC020978 could promote the nuclear translocation of PKM2 and regulate PKM2-enhanced HIF-1α transcription activity. Conclusions: Together, these data provided evidence that AC020978 conferred an aggressive phenotype to NSCLC and was a poor prognosticator. Targeting AC020978 might be an effective therapeutic strategy for NSCLC.

As a hallmark of metabolic reprogramming, aerobic glycolysis contributes to tumorigenesis and aggressiveness. However, the mechanisms and therapeutic strategies regulating aerobic glycolysis in neuroblastoma (NB), one of leading causes of cancer-related death in childhood, still remain elusive. Methods: Transcriptional regulators and their downstream glycolytic genes were identified by a comprehensive screening of publicly available datasets. Dual-luciferase, chromatin immunoprecipitation, real-time quantitative RT-PCR, western blot, gene over-expression or silencing, co-immunoprecipitation, mass spectrometry, peptide pull-down assay, sucrose gradient sedimentation, seahorse extracellular flux, MTT colorimetric, soft agar, matrigel invasion, and nude mice assays were undertaken to explore the biological effects and underlying mechanisms of transcriptional regulators in NB cells. Survival analysis was performed by using log-rank test and Cox regression assay. Results: Transcription factor myeloid zinc finger 1 (MZF1) was identified as an independent prognostic factor (hazard ratio=2.330, 95% confidence interval=1.021 to 3.317), and facilitated glycolysis process through increasing expression of hexokinase 2 (HK2) and phosphoglycerate kinase 1 (PGK1). Meanwhile, a 21-amino acid peptide encoded by upstream open reading frame of MZF1, termed as MZF1-uPEP, bound to zinc finger domain of Yin Yang 1 (YY1), resulting in repressed transactivation of YY1 and decreased transcription of MZF1 and downstream genes HK2 and PGK1. Administration of a cell-penetrating MZF1-uPEP or lentivirus over-expressing MZF1-uPEP inhibited the aerobic glycolysis, tumorigenesis and aggressiveness of NB cells. In clinical NB cases, low expression of MZF1-uPEP or high expression of MZF1, YY1, HK2, or PGK1 was associated with poor survival of patients. Conclusions: These results indicate that therapeutic targeting of YY1/MZF1 axis by MZF1-uPEP inhibits aerobic glycolysis and NB progression.

Casein kinase 1δ (CK1δ) and casein kinase 1ε (CK1ε) have been proposed to be involved in DNA replication, differentiation and apoptosis, thus participating in the regulation of tumorigenesis. However, their functions in colon cancer and the underlying mechanism remain unclear. Here, we found that the expression of CK1ε and CK1δ increased significantly in cancer tissues and the upregulation of CK1ε and CK1δ were closely related to poor differentiation, advanced TNM stage and poor prognosis of colon cancer. CK1δ/ε inhibitor IC261 could induce a decrease in cell survival and proliferation, and an increase in apoptosis in colon cancer cells. Interestingly, IC261 increased the level of aerobic glycolysis in colon cancer cells. Meanwhile, IC261 caused the decrease of p53 protein level and the misregulation of glycolysis related genes (TIGAR, G6PD, GLUT1) which are closely related to the regulation of glycolysis by p53. Inhibiting p53 by siRNA or inhibitor could significantly attenuate the upregulation of aerobic glycolysis induced by IC261. Finally, inhibition of aerobic glycolysis can further increase the cytotoxicity induced by IC261. Collectively, our results revealed that IC261 could inhibit the growth of colon cancer cells and increase the level of aerobic glycolysis, which is regulated by p53-dependent manner. This result suggested that targeting CK1δ/ε and glycolysis might be a valuable strategy treatment and combination therapies for colon cancer.

Glioblastoma (GBM) is an aggressive primary central nervous system neoplasia with limited therapeutic options and poor prognosis. Following reports of cytomegalovirus (HCMV) in GBM tumors, the anti-viral drug Valganciclovir was administered and found to significantly increase the longevity of GBM patients. While these findings suggest a role for HCMV in GBM, the relationship between them is not clear and remains controversial. Treatment with anti-viral drugs may prove clinically useful; however, their results do not explain the underlying mechanism between HCMV infection and GBM progression. We hypothesized that HCMV infection would metabolically reprogram GBM cells and that these changes would allow for increased tumor progression. We infected LN-18 GBM cells and employed a Seahorse Bioanalyzer to characterize cellular metabolism. Increased mitochondrial respiration and glycolytic rates were observed following infection. These changes were accompanied by elevated production of reactive oxygen species and lactate. Due to lactate’s numerous tumor-promoting effects, we examined the impact of paracrine signaling of HCMV-infected GBM cells on uninfected stromal cells. Our results indicated that, independent of viral transmission, the secretome of HCMV-infected GBM cells was able to alter the expression of key metabolic proteins and epigenetic markers. This suggests a mechanism of action where reprogramming of GBM cells alters the surrounding tumor microenvironment to be permissive to tumor progression in a manner akin to the Reverse-Warburg Effect. Overall, this suggests a potential oncomodulatory role for HCMV in the context of GBM.

Background Centromere protein N (CENP-N) has been reported to be highly expressed in malignancies, but its role and mechanism in nasopharyngeal carcinoma (NPC) are unknown. Methods Abnormal CENP-N expression from NPC microarrays of GEO database was analyzed. CENP-N expression level was confirmed in NPC tissues and cell lines. Stable CENP-N knockdown and overexpression NPC cell lines were established, and transcriptome sequencing after CENP-N knockdown was performed. In vitro and in vivo experiments were performed to test the impact of CENP-N knockdown in NPC cells. ChIP and dual luciferase reporter assays were used to verify the combination of IRF2 and CENP-N. Western blot analysis, cellular immunofluorescence, immunoprecipitation and GST pulldown assays were used to verify the combination of CENP-N and AKT. Results CENP-N was confirmed to be aberrantly highly expressed in NPC tissues and cell lines and to be associated with high 18F-FDG uptake in cancer nests and poor patient prognosis. Transcriptome sequencing after CENP-N knockdown revealed that genes with altered expression were enriched in pathways related to glucose metabolism, cell cycle regulation. CENP-N knockdown inhibited glucose metabolism, cell proliferation, cell cycling and promoted apoptosis. IRF2 is a transcription factor for CENP-N and directly promotes CENP-N expression in NPC cells. CENP-N affects the glucose metabolism, proliferation, cell cycling and apoptosis of NPC cells in vitro and in vivo through the AKT pathway. CENP-N formed a complex with AKT in NPC cells. Both an AKT inhibitor (MK-2206) and a LDHA inhibitor (GSK2837808A) blocked the effect of CENP-N overexpression on NPC cells by promoting aerobic glycolysis, proliferation, cell cycling and apoptosis resistance. Conclusions The IRF2/CENP-N/AKT axis promotes malignant biological behaviors in NPC cells by increasing aerobic glycolysis, and the IRF2/CENP-N/AKT signaling axis is expected to be a new target for NPC therapy.

Enhanced aerobic glycolysis constitutes an additional source of energy for tumor proliferation and metastasis. Human papillomavirus (HPV) infection is the main cause of cervical cancer (CC); however, the associated molecular mechanisms remain poorly defined, as does the relationship between CC and aerobic glycolysis. To investigate whether HPV 16/18 E6/E7 can enhance aerobic glycolysis in CC, E6/E7 expression was knocked down in SiHa and HeLa cells using small interfering RNA (siRNA). Then, glucose uptake, lactate production, ATP levels, reactive oxygen species (ROS) content, extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were evaluated. RNA-seq was used to probe the molecular mechanism involved in E6/E7-driven aerobic glycolysis, and identified IGF2BP2 as a target of E6/E7. The regulatory effect of IGF2BP2 was confirmed by qRT-PCR, western blot, and RIP assay. The biological roles and mechanisms underlying how HPV E6/E7 and IGF2BP2 promote CC progression were confirmed in vitro and in vivo. Human CC tissue microarrays were used to analyze IGF2BP2 expression in CC. The knockdown of E6/E7 and IGF2BP2 attenuated the aerobic glycolytic capacity and growth of CC cells, while IGF2BP2 overexpression rescued this effect in vitro and in vivo. IGF2BP2 expression was higher in CC tissues than in adjacent tissues and was positively correlated with tumor stage. Mechanistically, E6/E7 proteins promoted aerobic glycolysis, proliferation, and metastasis in CC cells by regulating MYC mRNA m6A modifications through IGF2BP2. We found that E6/E7 promote CC by regulating MYC methylation sites via activating IGF2BP2 and established a link between E6/E7 and the promotion of aerobic glycolysis and CC progression. Blocking the HPV E6/E7-related metabolic pathway represents a potential strategy for the treatment of CC.

Glioma is the most common and aggressive tumor of the central nervous system. The uncontrolled proliferation, cellular heterogeneity, and diffusive capacity of glioma cells contribute to a very poor prognosis of patients with high grade glioma. Compared to normal cells, cancer cells exhibit a higher rate of glucose uptake, which is accompanied with the metabolic switch from oxidative phosphorylation to aerobic glycolysis. The metabolic reprogramming of cancer cell supports excessive cell proliferation, which are frequently mediated by the activation of oncogenes or the perturbations of tumor suppressor genes. Recently, a growing body of evidence has started to reveal that long noncoding RNAs (lncRNAs) are implicated in a wide spectrum of biological processes in glioma, including malignant phenotypes and aerobic glycolysis. However, the mechanisms of diverse lncRNAs in the initiation and progression of gliomas remain to be fully unveiled. In this review, we summarized the diverse roles of lncRNAs in shaping the biological features and aerobic glycolysis of glioma. The thorough understanding of lncRNAs in glioma biology provides opportunities for developing diagnostic biomarkers and novel therapeutic strategies targeting gliomas.

Background Mounting evidence has suggested the essential role of long non-coding RNAs (lncRNAs) in a plethora of malignant tumors, including hepatocellular carcinoma. However, the underlyling mechanisms of lncRNAs remain unidentified in HCC. The present work was aimed to explore the regulatory functions and mechanisms of LncRNA LNCAROD in HCC progression and chemotherapeutic response. Methods The expression of LNCAROD in HCC tissues and cell lines were detected by quantitative reverse transcription PCR (qPCR). Cancer cell proliferation, migration, invasion, and chemoresistance were evaluated by cell counting kit 8 (CCK8), colony formation, transwell, and chemosensitivity assays. Methylated RNA immunoprecipitation qRCR (MeRIP-qPCR) was used to determine N6-methyladenosine (m6A) modification level. RNA immunoprecipitation (RIP) and RNA pull down were applied to identify the molecular sponge role of LNCAROD for modulation of miR-145-5p via the competing endogenous RNA (ceRNA) mechanism, as well as the interaction between LNCAROD and serine-and arginine-rich splicing factor 3 (SRSF3). The interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and LNCAROD was also identified by RIP assay. Gain- or-loss-of-function assays were used to identify the function and underlying mechanisms of LNCAROD in HCC. Results We found that LNCAROD was significantly upregulated and predicted a poorer prognosis in HCC patients. LNCAROD upregulation was maintained by increased m6A methylation-mediated RNA stability. LNCAROD significantly promoted HCC cell proliferation, migration, invasion, and chemoresistance both in vitro and in vivo. Furthermore, mechanistic studies revealed that pyruvate kinase isoform M2 (PKM2)-mediated glycolysis enhancement is critical for the role of LNACROD in HCC. According to bioinformatics prediction and our experimental data, LNCAROD directly binds to SRSF3 to induce PKM switching towards PKM2 and maintains PKM2 levels in HCC by acting as a ceRNA against miR-145-5p. The oncogenic effects of LNCAROD in HCC were more prominent under hypoxia than normoxia due to the upregulation of hypoxia-triggered hypoxia-inducible factor 1α. Conclusions In summary, our present study suggests that LNCAROD induces PKM2 upregulation via simultaneously enhancing SRSF3-mediated PKM switching to PKM2 and sponging miR-145-5p to increase PKM2 level, eventually increasing cancer cell aerobic glycolysis to participate in tumor malignancy and chemoresistance, especially under hypoxic microenvironment. This study provides a promising diagnostic marker and therapeutic target for HCC patients. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-021-02090-7.

Polyphenol-rich foods are gaining popularity due to their potential beneficial effects in the prevention and treatment of cancer. Foxtail millet is one of the important functional foods, riches in a variety of biologically active substance. Our previous study showed that ferulic acid (FA) and p-coumaric acid (p-CA) are the main anticancer components of foxtail millet bran, and the two have a significant synergistic effect. In the present study, the clinical application potential of FA and p-CA (FA + p-CA) were evaluated in vivo and in vitro. The FA and p-CA target gene enrichment analysis discovered that FA + p-CA were associated with aerobic glycolysis. It was further shown that FA + p-CA remodel aerobic glycolysis by inhibiting the glycolysis-associated lncRNA 495810 and the glycolytic rate-limiting enzyme M2 type pyruvate kinase (PKM2). Moreover, PKM2 expression was positively correlated with lncRNA 495810. More interestingly, the exogenous expression of lncRNA 495810 eliminated the inhibitory effects of FA + p-CA on aerobic glycolysis. Collectively, FA + p-CA obstruct the aerobic glycolysis of colorectal cancer cells via the lncRNA 495810/PKM2 axis, which provides a nutrition intervention and treatment candidate for colorectal cancer.

Background As a metabolic reprogramming feature, cancer cells derive most of their energy from aerobic glycolysis, while its regulatory mechanisms and therapeutic strategies continue to be illusive. Methods Integrative analysis of publically available expression profile datasets was used to identify critical transcriptional regulators and their target glycolytic enzymes. The functions and acting mechanisms of transcriptional regulators in cancer cells were investigated by using in vitro and in vivo assays. The Kaplan–Meier curve and log‐rank assay were used to conduct the survival study. Results Salmonella pathogenicity island 1 (SPI1/PU.1), a haematopoietic transcription factor, was identified to facilitate glycolytic process, tumourigenesis, invasiveness, as well as metastasis of colon cancer cells, which was interplayed by tumour‐associated neutrophils. Mechanistically, neutrophils delivered SPI1 mRNA via extracellular vesicles, resulting in enhanced SPI1 expression of cancer cells. Through physical interaction with SPI1‐related protein (SPIB), SPI1 drove expression of glycolytic genes within cancer cells, which in turn induced polarization of neutrophils via glycolytic metabolite lactate. Depletion of neutrophils or SPIB–SPI1 interaction in cancer cells significantly inhibited glycolytic process, tumourigenesis and aggressiveness. Upregulation of SPI1 or SPIB was found to be associated with poor prognosis in patients suffering from colon cancer. Conclusions Therapeutic targeting of SPIB/SPI1‐facilitated interplay of cancerous cells and neutrophils suppresses aerobic glycolysis and progression of cancer., Transcription factor SPI1 promotes aerobic glycolysis via upregulating HK2 and PGK1 in cancer cells. Neutrophils are polarized by SPI1‐facilitated glycolysis, which in turn deliver SPI1 mRNA into cancer cells via extracellular vesicles. SPIB facilitates SPI1 transactivation via physical interaction in cancer cells. Therapeutic targeting of SPIB–SPI1 interaction or neutrophils inhibits aerobic glycolysis and cancer progression.

Introduction and Objectives Warburg effect is attracting increasing attention as it is important for cancer progression. However, how cancer cells regulate glucose metabolism through glycolysis is still unknown. Here, we demonstrated the regulatory role of Ras related GTP binding D (RRAGD) in human hepatocellular carcinoma (HCC) cells. Patients or Materials and Methods Kaplan-Meier’s analysis was used to analyze the correlation between RRAGD expression levels and prognosis of HCC patients from the Cancer Genome Atlas database. Two stable RRAGD knockdown HCC cell lines were created using shRNAs to investigate cancer progression and aerobic glycolysis. Western blot and quantitative reverse transcription polymerase chain reaction were performed to detect the expression levels of RRAGD and MYC. Results RRAGD expression was elevated in HCC patients with poor prognosis. RRAGD knockdown could inhibit the proliferation, invasion and migration of Huh-7 and HepG2 cells. Interestingly, silence RRAGD was able to reduce the glucose uptake, lactate production and extracellular acidification rate of HCC. RRAGD expression level was up-regulated by oncogene MYC in HCC cells. Conclusion This study highlights RRAGD as an important cancer-promoting factor for cancer progression and aerobic glycolysis, and thereby it is a potential therapeutic target for HCC intervention.

Cancer cells are known to adopt aerobic glycolysis in order to fuel tumor growth, but the molecular basis of this metabolic shift remains largely undefined. O-GlcNAcase (OGA) is an enzyme harboring O-linked β-N-acetylglucosamine (O-GlcNAc) hydrolase and cryptic lysine acetyltransferase activities. Here, we report that OGA is upregulated in a wide range of human cancers and drives aerobic glycolysis and tumor growth by inhibiting pyruvate kinase M2 (PKM2). PKM2 is dynamically O-GlcNAcylated in response to changes in glucose availability. Under high glucose conditions, PKM2 is a target of OGA-associated acetyltransferase activity, which facilitates O-GlcNAcylation of PKM2 by O-GlcNAc transferase (OGT). O-GlcNAcylation inhibits PKM2 catalytic activity and thereby promotes aerobic glycolysis and tumor growth. These studies define a causative role for OGA in tumor progression and reveal PKM2 O-GlcNAcylation as a metabolic rheostat that mediates exquisite control of aerobic glycolysis.

DT‐13 combined with topotecan (TPT) showed stronger antitumour effects in mice subcutaneous xenograft model compared with their individual effects in our previous research. Here, we further observed the synergistically effect in mice orthotopic xenograft model. Metabolomics analysis showed DT‐13 combined with TPT alleviated metabolic disorders induced by tumour and synergistically inhibited the activity of the aerobic glycolysis‐related enzymes in vivo and in vitro. Mechanistic studies revealed that the combination treatment promoted epidermal growth factor receptor (EGFR) degradation through non‐muscle myosin IIA (NM IIA)‐induced endocytosis of EGFR, further inhibited the activity of hexokinase II (HK II), and eventually promoted the aerobic glycolysis inhibition activity more efficiently compared with TPT or DT‐13 monotherapy. The combination therapy also inhibited the specific binding of HK II to mitochondria. When using the NM II inhibitor (‐)002Dblebbistatin or MYH‐9 shRNA, the synergistic inhibition effect of DT‐13 and TPT on aerobic glycolysis was eliminated in BGC‐823 cells. Immunohistochemical analysis revealed selective up‐regulation of NM IIA while specific down‐regulation of p‐CREB, EGFR, and HK II by the combination therapy. Collectively, these findings suggested that this regimen has significant clinical implications, warranted further investigation.

Pyruvate kinase M2 (PKM2), playing a central role in regulating aerobic glycolysis, was considered as a promising target for cancer therapy. However, its role in cancer metastasis is rarely known. Here, we found a tight relationship between PKM2 and breast cancer metastasis, demonstrated by the findings that beta‐elemene (β‐elemene), an approved drug for complementary cancer therapy, exerted distinct anti‐metastatic activity dependent on PKM2. The results indicated that β‐elemene inhibited breast cancer cell migration, invasion in vitro as well as metastases in vivo. β‐Elemene further inhibited the process of aerobic glycolysis and decreased the utilization of glucose and the production of pyruvate and lactate through suppressing pyruvate kinase activity by modulating the transformation of dimeric and tetrameric forms of PKM2. Further analysis revealed that β‐elemene suppressed aerobic glycolysis by blocking PKM2 nuclear translocation and the expression of EGFR, GLUT1 and LDHA by influencing the expression of importin α5. Furthermore, the effect of β‐elemene on migration, invasion, PKM2 transformation, and nuclear translocation could be reversed in part by fructose‐1,6‐bisphosphate (FBP) and L‐cysteine. Taken together, tetrameric transformation and nuclear translocation of PKM2 are essential for cancer metastasis, and β‐elemene inhibited breast cancer metastasis via blocking aerobic glycolysis mediated by dimeric PKM2 transformation and nuclear translocation, being a promising anti‐metastatic agent from natural compounds.

Background: Cancer cells favor the use of less efficient glycolysis rather than mitochondrial oxidative phosphorylation to metabolize glucose, even in oxygen-rich conditions, a distinct metabolic alteration named the Warburg effect or aerobic glycolysis. In adult cells, bifunctional 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase (PFKFB) family members are responsible for controlling the steady-state cytoplasmic levels of fructose-2,6-bisphosphate, which allosterically activates 6-phosphofructo-1-kinase, the key enzyme catalyzing the rate-limiting reaction of glycolysis. PFKFB3 and PFKFB4 are the two main isoenzymes overexpressed in various human cancers. Scope of review: In this review, we summarize recent findings on the glycolytic and extraglycolytic roles of PFKFB3 and PFKFB4 in cancer progression and discuss potential therapies for targeting of PFKFB3 and PFKFB4. Major conclusions: PFKFB3 has the highest kinase activity to shunt glucose toward glycolysis, whereas PFKFB4 has more FBPase-2 activity, redirecting glucose toward the pentose phosphate pathway, providing reducing power for lipid biosynthesis and scavenging reactive oxygen species. Co-expression of PFKFB3 and PFKFB4 provides sufficient glucose metabolism to satisfy the bioenergetics demand and redox homeostasis requirements of cancer cells. Various reversible post-translational modifications of PFKFB3 enable cancer cells to flexibly adapt glucose metabolism in response to diverse stress conditions. In addition to playing important roles in tumor cell glucose metabolism, PFKFB3 and PFKFB4 are widely involved in multiple biological processes, such as cell cycle regulation, autophagy, and transcriptional regulation in a non-glycolysis-dependent manner. Keywords: Warburg effect, Aerobic glycolysis, 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase, Pentose phosphate pathway, Metabolic reprogramming

Tumor suppressor p53 is a master regulator of apoptosis and plays key roles in cell cycle checkpoints. p53 responds to metabolic changes and alters metabolism through several mechanisms in cancer. Lactate dehydrogenase A (LDHA), a key enzyme in glycolysis, is highly expressed in a variety of tumors and catalyzes pyruvate to lactate. In the present study, we first analyzed the association and clinical significance of p53 and LDHA in breast cancer expressing wild-type p53 (wt-p53) and found that LDHA mRNA levels are negatively correlated with wt-p53 but not with mutation p53 mRNA levels, and low p53 and high LDHA expression are significantly associated with poor overall survival rates. Furthermore, p53 negatively regulates LDHA expression by directly binding its promoter region. Moreover, a series of LDHA gain-of-function and rescore experiments were carried out in breast cancer MCF7 cells expressing endogenous wt-p53, showing that ectopic expression of p53 decreases aerobic glycolysis, cell proliferation, migration, invasion and tumor formation of breast cancer cells and that restoration of the expression of LDHA in p53-overexpressing cells could abolish the suppressive effect of p53 on aerobic glycolysis and other malignant phenotypes. In conclusion, our findings showed that repression of LDHA induced by wt-p53 blocks tumor growth and invasion through downregulation of aerobic glycolysis in breast cancer, providing new insights into the mechanism by which p53 contributes to the development and progression of breast cancer.

Background and Aims: Cancer cells prefer aerobic glycolysis to maintain growth advantages, but the role of long non-coding RNAs (lncRNAs) in glycometabolism still remains unclear. Here we identified one cytoplasmic lncRNA LINC01554 as a significantly downregulated lncRNA in hepatocellular carcinoma (HCC) and aimed to investigate its role in cellular glucose metabolism in the development and progression of HCC. Methods: Quantitative real-time PCR was used to determine the expression level of LINC01554. Downregulation of LINC01554 by miR-365a at transcriptional level was assessed by luciferase reporter assay. Subcellular fractionation assay and RNA fluorescence in situ hybridization were performed to detect the subcellular localization of LINC01554. RNA pull-down assay, mass spectrometry, and RNA immunoprecipitation assay were used to identify the underlying molecular mechanisms. The tumor-suppressive function of LINC01554 was determined by both in vitro assay and nude mice xenograft model. Results: LINC01554 was frequently downregulated in HCC, which was significantly associated with tumor invasion (P = 0.005), tumor size (P = 0.041), tumor staging (P = 0.023) and shorter survival (P = 0.035) of HCC patients. Luciferase reporter assay unraveled that LINC01554 was negatively regulated by miR-365a. Subcellular fractionation assay and RNA FISH revealed the cytoplasmic predominance of LINC01554 in MIHA cells and HCC clinical samples. Ectopic expression of LINC01554 inhibited HCC cell growth, colony formation in soft agar, foci formation, and tumor formation in nude mice. LINC01554 promoted the ubiquitin-mediated degradation of PKM2 and inhibited Akt/mTOR signaling pathway to abolish aerobic glycolysis in HCC cells. Further study found that LINC01554-knockout could effectively reverse the tumor-suppressive effect of LINC01554. Conclusions: Our results identify LINC01554 as a novel tumor suppressor in HCC and unravel its underlying molecular mechanism in reprogramming cellular glucose metabolism. LINC01554 could possibly serve as a novel prognostic biomarker and provide the rationale for HCC therapy.

MicroRNAs (miRNAs) have been recently found in the mitochondria, and were named “mitomiRs”, but their function has remained elusive. Here, we aimed to assess the presence and function(s) of mitomiRs in tongue squamous cell carcinoma (TSCC). Methods: miRNA microarray was performed in paired TSCC cell lines, Cal27 and its chemoresistant counterpart, Cal27-re. Decreased expression of mitomiRs in chemoresistant cells was characterized. The functions of mitomiRs were investigated by a series of in vitro and in vivo experiments. Results: Differential microarray analysis identified downregulation of mitomiR-5787 in Cal27-re cells. We knocked down mitomiR-5787 in parental cells and upregulated its expression in cisplatin-resistant cells. The sensitivity of TSCC cells to cisplatin was regulated by miR-5787. The glucose metabolism assay suggested that reduced expression of miR-5787 changed the balance of glucose metabolism by shifting it from oxidative phosphorylation to aerobic glycolysis. Xenograft experiments in BALB/c-nu mice further verified the in vitro results. Reduced expression of miR-5787 contributes to chemoresistance in TSCC cells by inhibiting the translation of mitochondrial cytochrome c oxidase subunit 3 (MT-CO3). The prognostic analysis of 126 TSCC patients showed that the patients with low expression of miR-5787 and/or MT-CO3 had poor cisplatin sensitivity and prognosis. Conclusions: Mitochondrial miR-5787 could regulate cisplatin resistance of TSCC cells and affect oxidative phosphorylation and aerobic glycolysis. Downregulation of miR-5787 inhibited the translation of MT-CO3 to regulate cisplatin resistance of TSCC. Mitochondrial miR-5787 and MT-CO3 can be used as predictive biomarkers or therapeutic targets for cisplatin chemotherapy resistance.

Background Epithelial-to-mesenchymal transition (EMT) and aerobic glycolysis are fundamental processes implicated in cancer metastasis. Although increasing evidence demonstrates an association between EMT induction and enhanced aerobic glycolysis in human cancer, the mechanisms linking these two conditions in endometrial cancer (EC) cells remain poorly defined. Methods We characterized the role and molecular mechanism of the glycolytic enzyme hexokinase 2 (HK2) in mediating EMT and glycolysis and investigated how long noncoding RNA DLEU2 contributes to the stimulation of EMT and glycolysis via upregulation of HK2 expression. Results HK2 was highly expressed in EC tissues, and its expression was associated with poor overall survival. Overexpression of HK2 effectively promoted EMT phenotypes and enhanced aerobic glycolysis in EC cells via activating FAK and its downstream ERK1/2 signaling. Moreover, microRNA-455 (miR-455) served as a tumor suppressor by directly interacting with HK2 mRNA and inhibiting its expression. Furthermore, DLEU2 displayed a significantly higher expression in EC tissues, and increased DLEU2 expression was correlated with worse overall survival. DLEU2 acted as an upstream activator for HK2-induced EMT and glycolysis in EC cells through two distinct mechanisms: (i) DLEU2 induced HK2 expression by competitively binding with miR-455, and (ii) DLEU2 also interacted with EZH2 to silence a direct inhibitor of HK2, miR-181a. Conclusions This study identified DLEU2 as an upstream activator of HK2-driven EMT and glycolysis in EC cells and provided significant mechanistic insights for the potential treatment of EC.

Cancer cells alter metabolic processes to sustain their characteristic uncontrolled growth and proliferation. These metabolic alterations include (1) a shift from oxidative phosphorylation to aerobic glycolysis to support the increased need for ATP, (2) increased glutaminolysis for NADPH regeneration, (3) altered flux through the pentose phosphate pathway and the tricarboxylic acid cycle for macromolecule generation, (4) increased lipid uptake, lipogenesis, and cholesterol synthesis, (5) upregulation of one-carbon metabolism for the production of ATP, NADH/NADPH, nucleotides, and glutathione, (6) altered amino acid metabolism, (7) metabolism-based regulation of apoptosis, and (8) the utilization of alternative substrates, such as lactate and acetate. Altered metabolic flux in cancer is controlled by tumor-host cell interactions, key oncogenes, tumor suppressors, and other regulatory molecules, including non-coding RNAs. Changes to metabolic pathways in cancer are dynamic, exhibit plasticity, and are often dependent on the type of tumor and the tumor microenvironment, leading in a shift of thought from the Warburg Effect and the “reverse Warburg Effect” to metabolic plasticity. Understanding the complex nature of altered flux through these multiple pathways in cancer cells can support the development of new therapies.