scholarly journals Double genetic disruption of lactate dehydrogenases A and B is required to ablate the “Warburg effect” restricting tumor growth to oxidative metabolism

2018 ◽  
Vol 293 (41) ◽  
pp. 15947-15961 ◽  
Author(s):  
Maša Ždralević ◽  
Almut Brand ◽  
Lorenza Di Ianni ◽  
Katja Dettmer ◽  
Jörg Reinders ◽  
...  

Increased glucose consumption distinguishes cancer cells from normal cells and is known as the “Warburg effect” because of increased glycolysis. Lactate dehydrogenase A (LDHA) is a key glycolytic enzyme, a hallmark of aggressive cancers, and believed to be the major enzyme responsible for pyruvate-to-lactate conversion. To elucidate its role in tumor growth, we disrupted both the LDHA and LDHB genes in two cancer cell lines (human colon adenocarcinoma and murine melanoma cells). Surprisingly, neither LDHA nor LDHB knockout strongly reduced lactate secretion. In contrast, double knockout (LDHA/B-DKO) fully suppressed LDH activity and lactate secretion. Furthermore, under normoxia, LDHA/B-DKO cells survived the genetic block by shifting their metabolism to oxidative phosphorylation (OXPHOS), entailing a 2-fold reduction in proliferation rates in vitro and in vivo compared with their WT counterparts. Under hypoxia (1% oxygen), however, LDHA/B suppression completely abolished in vitro growth, consistent with the reliance on OXPHOS. Interestingly, activation of the respiratory capacity operated by the LDHA/B-DKO genetic block as well as the resilient growth were not consequences of long-term adaptation. They could be reproduced pharmacologically by treating WT cells with an LDHA/B-specific inhibitor (GNE-140). These findings demonstrate that the Warburg effect is not only based on high LDHA expression, as both LDHA and LDHB need to be deleted to suppress fermentative glycolysis. Finally, we demonstrate that the Warburg effect is dispensable even in aggressive tumors and that the metabolic shift to OXPHOS caused by LDHA/B genetic disruptions is responsible for the tumors' escape and growth.

2021 ◽  
Author(s):  
Shonagh Russell ◽  
Liping Xu ◽  
Yoonseok Kam ◽  
Dominique Abrahams ◽  
Bryce Ordway ◽  
...  

Aggressive cancers commonly ferment glucose to lactic acid at high rates, even in the presence of oxygen. This is known as aerobic glycolysis, or the “Warburg Effect”. It is widely assumed that this is a consequence of the upregulation of glycolytic enzymes. Oncogenic drivers can increase the expression of most proteins in the glycolytic pathway, including the terminal step of exporting H+ equivalents from the cytoplasm. Proton exporters maintain an alkaline cytoplasmic pH, which can enhance all glycolytic enzyme activities, even in the absence of oncogene-related expression changes. Based on this observation, we hypothesized that increased uptake and fermentative metabolism of glucose could be driven by the expulsion of H+ equivalents from the cell. To test this hypothesis, we stably transfected lowly-glycolytic MCF-7, U2-OS, and glycolytic HEK293 cells to express proton exporting systems: either PMA1 (yeast H+-ATPase) or CAIX (carbonic anhydrase 9). The expression of either exporter in vitro enhanced aerobic glycolysis as measured by glucose consumption, lactate production, and extracellular acidification rate. This resulted in an increased intracellular pH, and metabolomic analyses indicated that this was associated with an increased flux of all glycolytic enzymes upstream of pyruvate kinase. These cells also demonstrated increased migratory and invasive phenotypes in vitro, and these were recapitulated in vivo by more aggressive behavior, whereby the acid-producing cells formed higher grade tumors with higher rates of metastases. Neutralizing tumor acidity with oral buffers reduced the metastatic burden. Therefore, cancer cells with increased H+ export increase intracellular alkalization, even without oncogenic driver mutations, and this is sufficient to alter cancer metabolism towards a Warburg phenotype.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e15123-e15123
Author(s):  
Dawei Li ◽  
Qingguo Li ◽  
Sanjun Cai ◽  
Keping Xie

e15123 Background: Aberrant expression of Forkhead Box transcription factors plays vital roles in the oncogenesis and metastasis of many types of cancer. The purpose of this study is to elucidate the function of Forkhead Box C1(FOXC1) in colorectal cancer (CRC)malignancy maintenance. Methods: FOXC1 expression in CRC specimens was analyzed in the TCGA database and validated by immunohistochemistry using a tissue microarray (TMA). The effect of FOXC1 expression on cancer proliferation and glycolysis was assessed in cells by altering the expression of FOXC1 in vitro and in vivo. Mechanistic investigation was carried out by using cell and molecular biology approaches. Results: FOXC1 was found to be overexpressed in CRC specimens compared with that in the adjacent benign tissues. Univariate survival analyses of the TCGA and validated cohorts showed that high expression of FOXC1 was significantly correlated with shortened patient survival ( P< 0.05). Attenuation of FOXC1 expression inhibited proliferation, clone formation and decreased glucose consumption and lactate production. By contrast, overexpression of FOXC1 had the opposite effect. Furthermore, increased FOXC1 expression downregulated the expression of a key glycolytic enzyme,fructose-1, 6-Bisphosphatase 1 (FBP1). Mechanistically, FOXC1 bound directly to the promoter regions of the FBP1 gene and negatively regulated its transcriptional activity. Aberrant FBP1 expression contributes to CRC tumorigenicity, and decreased FBP1 coupled with increased FOXC1 provided better prognostic information than FOXC1 did alone. Conclusions: The FOXC1/FBP1 axis induces cell proliferation, reprograms the metabolic process in CRC and provides potential prognostic predictors and therapeutic targets for patients with CRC.


2014 ◽  
Vol 204 (5) ◽  
pp. 729-745 ◽  
Author(s):  
Takumi Mikawa ◽  
Takeshi Maruyama ◽  
Koji Okamoto ◽  
Hitoshi Nakagama ◽  
Matilde E. Lleonart ◽  
...  

Despite the well-documented clinical significance of the Warburg effect, it remains unclear how the aggressive glycolytic rates of tumor cells might contribute to other hallmarks of cancer, such as bypass of senescence. Here, we report that, during oncogene- or DNA damage–induced senescence, Pak1-mediated phosphorylation of phosphoglycerate mutase (PGAM) predisposes the glycolytic enzyme to ubiquitin-mediated degradation. We identify Mdm2 as a direct binding partner and ubiquitin ligase for PGAM in cultured cells and in vitro. Mutations in PGAM and Mdm2 that abrogate ubiquitination of PGAM restored the proliferative potential of primary cells under stress conditions and promoted neoplastic transformation. We propose that Mdm2, a downstream effector of p53, attenuates the Warburg effect via ubiquitination and degradation of PGAM.


Author(s):  
Cheng-Wei Wang ◽  
Arunima Purkayastha ◽  
Kevin T Jones ◽  
Shivani K Thaker ◽  
Utpal Banerjee

2017 ◽  
Vol 114 (52) ◽  
pp. 13732-13737 ◽  
Author(s):  
Yang Wang ◽  
Jia Liu ◽  
Xin Jin ◽  
Dapeng Zhang ◽  
Dongxue Li ◽  
...  

The Warburg effect, characterized by increased glucose uptake and lactate production, is a well-known universal across cancer cells and other proliferating cells. PKM2, a splice isoform of the pyruvate kinase (PK) specifically expressed in these cells, serves as a major regulator of this metabolic reprogramming with an adjustable activity subjected to numerous allosteric effectors and posttranslational modifications. Here, we have identified a posttranslational modification on PKM2, O-GlcNAcylation, which specifically targets Thr405 and Ser406, residues of the region encoded by the alternatively spliced exon 10 in cancer cells. We show that PKM2 O-GlcNAcylation is up-regulated in various types of human tumor cells and patient tumor tissues. The modification destabilized the active tetrameric PKM2, reduced PK activity, and led to nuclear translocation of PKM2. We also observed that the modification was associated with an increased glucose consumption and lactate production and enhanced level of lipid and DNA synthesis, indicating that O-GlcNAcylation promotes the Warburg effect. In vivo experiments showed that blocking PKM2 O-GlcNAcylation attenuated tumor growth. Thus, we demonstrate that O-GlcNAcylation is a regulatory mechanism for PKM2 in cancer cells and serves as a bridge between PKM2 and metabolic reprogramming typical of the Warburg effect.


Author(s):  
Tianxin Ye ◽  
Yingchun Liang ◽  
Deyu Zhang ◽  
Xuewu Zhang

The Warburg effect (aerobic glycolysis) is a hallmark of cancer and is becoming a promising target for diagnosis and therapy. Phosphoglycerate kinase 1 (PGK1) is the first adenosine triphosphate (ATP)-generating glycolytic enzyme in the aerobic glycolysis pathway and plays an important role in cancer development and progression. However, how microRNAs (miRNAs) regulate PGK1-mediated aerobic glycolysis remains unknown. Here, we show that miR-16-1-3p inhibits PGK1 expression by directly targeting its 3′-untranslated region. Through inhibition of PGK1, miR-16-1-3p suppressed aerobic glycolysis by decreasing glucose uptake, lactate and ATP production, and extracellular acidification rate, and increasing oxygen consumption rate in breast cancer cells. Aerobic glycolysis regulated by the miR-16-1-3p/PGK1 axis is critical for modulating breast cancer cell proliferation, migration, invasion and metastasis in vitro and in vivo. In breast cancer patients, miR-16-1-3p expression is negatively correlated with PGK1 expression and breast cancer lung metastasis. Our findings provide clues regarding the role of miR-16-1-3p as a tumor suppressor in breast cancer through PGK1 suppression. Targeting PGK1 through miR-16-1-3p could be a promising strategy for breast cancer therapy.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shouhua Wang ◽  
Tingting Su ◽  
Huanjun Tong ◽  
Di Zhou ◽  
Fei Ma ◽  
...  

AbstractGallbladder cancer (GBC) is the most malignant cancer of the biliary tract cancer and presents poor prognosis. CircRNAs have been identified as critical regulators of multiple stages in tumor progression. In the study, we first demonstrated that circular RNA circβ-catenin expression was upregulated in GBC tissues when compared to adjacent normal tissues and associated with advanced clinical stage and poor prognosis in GBC patients. Silencing of circβ-catenin obviously suppressed GBC cell proliferation and cell cycle progression in vitro, but circβ-catenin overexpression had the opposite effects. In vivo, silencing of circβ-catenin inhibited tumor growth. Furthermore, we also found that circβ-catenin promoted GBC cell lactate production, pyruvate production, ATP quantity, and extracellular acidification rate (ECAR), which suggested that circβ-catenin regulated Warburg effect in GBC. Mechanistic analysis further highlighted that circβ-catenin promoted Stathmin 1 (STMN1) expression through sponging miR-223 in GBC progression. In addition, knockdown of STMN1 inhibited cell growth and Warburg effect in GBC. In summary, our findings indicated that circβ-catenin/miR-223/STMN1 axis could regulate cell growth and Warburg effect in GBC. Targeting circβ-catenin might be a potential therapeutic strategy for GBC.


2013 ◽  
Vol 17 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Brandon Faubert ◽  
Gino Boily ◽  
Said Izreig ◽  
Takla Griss ◽  
Bozena Samborska ◽  
...  

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