Expression of SIP1 is strongly correlated with LDHA and shows a significantly poor outcome in gastric cancer

Regulatory effect of tetramethylpyrazine on cell proliferation, migration, invasion, and glycolysis in gastric cancer cells

BACKGROUND

Tetramethylpyrazine (TMP) has been reported to have antitumor effects, but its effect on gastric cancer and the underlying mechanism are not fully understood.

AIM

To investigate the regulatory effect and potential mechanism of TMP on the proliferation, migration, invasion, and glycolysis of gastric cancer cells.

METHODS

Gastric cancer cells cultured in vitro were randomly divided into four groups: Control group (Ctrl), low-dose TMP group (TMP-L, 10 μM), medium-dose TMP group (TMP-M, 20 μM), and high-dose TMP group (TMP-H, 40 μM). After treatment, cell viability was detected by CCK-8 assay, and cell proliferation, migration, and invasion were detected by colony formation assay and transwell assay. Glucose metabolism was determined by measurements of glucose uptake, lactate production, oxygen consumption rate (OCR), and extracellular acidification rate (ECAR). The activity of hexokinase (HK) and lactate dehydrogenase (LDH) was determined. The expression of glycolysis-related proteins and activation of the protein kinase B (AKT)/glucose trans-porter-1 (GLUT1) axis were assessed by Western blot assay.

RESULTS

TMP reduced the viability of gastric cancer cells in a dose-dependent manner (P < 0.05). Compared to the Ctrl group, medium- and high-dose TMP inhibited cell proliferation, migration, and invasion (P < 0.05). After treatment with TMP, glucose uptake, lactate production, OCR, and ECAR were decreased significantly (P < 0.05), and the activity of HK and LDH was reduced significantly in the TMP-H group (P < 0.05). Western blot analysis showed that the expression of p-AKT/AKT, GLUT1, HK2, and LDHA in gastric cancer cells treated with TMP was downregulated (P < 0.05).

CONCLUSION

TMP reduces glycolysis and inhibits cell proliferation and migration in gartric cancer cells.

Natural compounds targeting glycolysis as promising therapeutics for gastric cancer: A review

Gastric cancer, a common malignant disease, seriously endangers human health and life. The high mortality rate due to gastric cancer can be attributed to a lack of effective therapeutic drugs. Cancer cells utilize the glycolytic pathway to produce energy even under aerobic conditions, commonly referred to as the Warburg effect, which is a characteristic of gastric cancer. The identification of new targets based on the glycolytic pathway for the treatment of gastric cancer is a viable option, and accumulating evidence has shown that phytochemicals have extensive anti-glycolytic properties. We reviewed the effects and mechanisms of action of phytochemicals on aerobic glycolysis in gastric cancer cells. Phytochemicals can effectively inhibit aerobic glycolysis in gastric cancer cells, suppress cell proliferation and migration, and promote apoptosis, via the PI3K/Akt, c-Myc, p53, and other signaling pathways. These pathways affect the expressions of HIF-1α, HK2, LDH, and other glycolysis-related proteins. This review further assesses the potential of using plant-derived compounds for the treatment of gastric cancer and sheds insight into the development of new drugs.

Essential role of aerobic glycolysis in epithelial-to-mesenchymal transition during carcinogenesis

Epithelial-to-mesenchymal transition (EMT) confers the most lethal characteristics to cancer cells i.e., metastasis and resistance to chemo-and-radio-therapy, and therefore exhibit an appealing target in the field of oncology. Research in the past decade has demonstrated the crucial role of aerobic glycolysis in EMT, which is generally credited as the glucose metabolism for the creation of biomass such as fatty acids, amino acids, and nucleotides thereby providing building blocks for limitless proliferation. In the present review, apart from discussing EMT's evident role in the metastatic process and cancer stemness, we also talked about the vital role of glycolytic enzymes viz. GLUTs, HKs, PGI, PFK-1, aldolase, enolase, PK, LDHA, etc. in the induction of the EMT process in cancerous cells.

Improvement of Diagnostic Accuracy for Pancreatic Cancer with Serum Lactate Dehydrogenase

Purpose

Due to the lack of early-stage detection, pancreatic cancer (PC) remains a devastating disease worldwide. Lactate dehydrogenase (LDH) is associated with tumorigenesis and cancer progression. This study aims to analyze the diagnostic improvements in serum LDH levels combined with other common tumor biomarkers, including carbohydrate antigen 19–9 (CA19–9) and carcinoembryonic antigen (CEA), for monitoring PC.

Patients and Methods

A retrospective analysis was performed on 73 patients with newly diagnosed PC, 90 patients with pancreatic benign diseases (PBD), and 92 people with healthy physical examination (HPE) at Zhongda Hospital, Southeast University from July 2013 to July 2020. The diagnostic efficiencies of serum levels of LDH, CA19–9, and CEA were analyzed through receiver operating characteristic (ROC) curves for PC. The sensitivity and specificity were evaluated at an optimal cutoff. The prognostic impacts of LDH on PC patients were also assessed.

Results

The LDH level was elevated in 21 (28.77%) patients with PC, 3 (3.33%) PBD patients, and no HPE individuals (P<0.05). The sensitivities of LDH, CA19–9, and CEA for the diagnosis of PC were 63.0%, 78.1%, and 72.6%, respectively, but the combination of these three markers increased predictive sensitivity significantly to 87.6%. The specificities of LDH, CA19–9, and CEA for the diagnosis of PC were 93.4%, 84.1%, and 73.1%, respectively. The combined specificity reached up to 96.7%. The medium survival time of PC patients with low-level LDH was 21 ± 5.1 months, whereas that of patients with high-level LDH was only 7 ± 0.92 months (P<0.05).

Conclusion

The serum LDH level was higher in PC patients than in PBD patients and HPE individuals and was associated with a poor prognosis. The combined assessment of LDH, CEA, and CA19–9 showed higher sensitivity and specificity for the diagnosis of PC.

Glycolytic competence in gastric adenocarcinomas negatively impacts survival outcomes of patients treated with salvage paclitaxel-ramucirumab

INTRODUCTION

For energy production, cancer cells maintain a high rate of glycolysis instead of oxidative phosphorylation converting glucose into lactic acid. This metabolic shift is useful to survive in unfavorable microenvironments. We investigated whether a positive glycolytic profile (PGP) in gastric adenocarcinomas may be associated with unfavorable outcomes under an anticancer systemic therapy, including the anti-angiogenic ramucirumab.

MATERIALS AND METHODS

Normal mucosa (NM) and primary tumor (PT) of 40 metastatic gastric adenocarcinomas patients who received second-line paclitaxel-ramucirumab (PR) were analyzed for mRNA expression of the following genes: HK-1, HK-2, PKM-2, LDH-A, and GLUT-1. Patients were categorized with PGP when at least a doubling of mRNA expression (PT vs. NM) in all glycolytic core enzymes (HK-1 or HK-2, PKM-2, LDH-A) was observed. PGP was also related to TP53 mutational status.

RESULTS

Mean LDH-A, HK-2, PKM-2 mRNA expression levels were significantly higher in PT compared with NM. 18 patients were classified as PGP, which was associated with significantly worse progression-free and overall survival times. No significant association was observed between PGP and clinical-pathologic features, including TP53 positive mutational status, in 28 samples.

CONCLUSIONS

Glycolytic proficiency may negatively affect survival outcomes of metastatic gastric cancer patients treated with PR systemic therapy. TP53 mutational status alone does not seem to explain such a metabolic shift.

Protective effects of Weipixiao decoction against MNNG-induced gastric precancerous lesions in rats

Gastric cancer is recognized as one of the most common cancer. In-depth research of gastric precancerous lesions (GPL) plays an important role in preventing the occurrence of gastric cancer. Meanwhile, traditional treatment provides a novel sight in the prevention of occurrence and development of gastric cancer. The current study was designed to assess the effects of therapy with Weipixiao (WPX) decoction on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced GPL rats and the underlying molecular mechanisms. After 10-weeks treatment, all rats were sacrificed. Histopathological changes of gastric tissue were assessed via hematoxylin-eosin (HE) and High-iron diamine-Alcian blue-Periodic acid-Schiff (HID-AB-PAS) staining. To be fully evidenced, RT-qPCR, Western blot and immunohistochemistry were used to detect the expressions of LDHA, CD147, HIF-1α, MCT4, PI3K, AKT, mTOR and miRNA-34a, which were crucial factors for evaluating GPL in the aspect of glycolysis pathogenesis. According to the results of HE and HID-AB-PAS staining, it could be confirmed that MNNG-induced GPL rats were obviously reversed by WPX decoction. Additionally, the increased gene levels of LDHA, CD147, MCT4, PI3K, AKT, mTOR and HIF-1α in model group were down-regulated by WPX decoction, while miRNA-34a expression was decreased and up-regulated by WPX decoction. The significantly increased protein levels of LDHA, CD147, MCT4, PI3K, AKT, mTOR and HIF-1α induced by MNNG were attenuated in rats treated with WPX decoction. In brief, the findings of this study imply that abnormal glycolysis in MNNG-induced GPL rats was relieved by WPX decoction via regulation of the expressions of LDHA, CD147, HIF-1α, MCT4, PI3K, AKT, mTOR and miRNA-34a.

Prognostic Value of Lactate Dehydrogenase Expression in Different Cancers: A Meta-Analysis

BACKGROUND

This meta-analysis was performed to elucidate the association between the expression of lactate dehydrogenase (LDH) and the prognosis of various malignant neoplasms.

MATERIALS AND METHODS

Qualified studies were systematically identified from relevant databases, including PubMed, Cochrane Library, Embase, WanFang, and HowNet. A total of 17 eligible studies with 4,176 patients that complied with the inclusion criteria were enrolled in this meta-analysis. The 17 articles were published from 2011 to 2018. The hazard ratio (HR) and 95% confidence interval (95%CI) were obtained from the selected studies.

RESULTS

The analysis that included all LDH-related studies showed a significant association with the overall survival (OS) outcome (HR = 1.74, P = 0.001) but exhibited an insignificant association with the disease-free survival (DFS) or recurrence-free survival (RFS) outcome (HR = 1.40, P = 0.072). High lactate dehydrogenase A (LDHA) expression was significantly relevant to inferior OS (HR = 1.88, 95%CI: 1.37-2.59) and DFS or RFS (HR = 1.56, 95%CI: 1.29-1.89).

CONCLUSIONS

High LDH expression and the prognostic outcome of various cancer patients are significantly correlated. High LDHA expression is a promising biomarker for forecasting the survival of patients and the recurrence of different cancers in these patients. Further associative studies are required due to the complex role of LDH genes.

Lactate and cancer: a "lactatic" perspective on spinal tumor metabolism (part 1)

Spine tumors are among the most difficult tumors to treat given their proximity to the spinal cord. Despite advances in adjuvant therapies, surgery remains a critical component of treatment, both in primary tumors and metastatic disease. Given the significant morbidity of these surgeries and with other current adjuvant therapies (e.g., radiation, chemotherapy), interest has grown in other methods of targeting tumors of the spine. Recent efforts have highlighted the tumor microenvironment, and specifically lactate, as central to tumorigenesis. Once erroneously considered a waste product that indicated hypoxia/hypoperfusion, lactate is now known to be at the center of whole-body metabolism, shuttling between tissues and being used as a fuel. Diffusion-driven transporters and the near-equilibrium enzyme lactate dehydrogenase (LDH) allow rapid mobilization of large stores of muscle glycogen in the form of lactate. In times of stress, catecholamines can bind muscle cell receptors and trigger the breakdown of glycogen to lactate, which can then diffuse out into circulation and be used as a fuel where needed. Hypoxia, in contrast, is rarely the reason for an elevated arterial [lactate]. Tumors were originally described in the 1920's as being "glucose-avid" and "lactate-producing" even in normoxia (the "Warburg effect"). We now know that a broad range of metabolic behaviors likely exist, including cancer cells that consume lactate as a fuel, others that may produce it, and still others that may change their behavior based on the local microenvironment. In this review we will examine the relationship between lactate and tumor metabolism with a brief look at spine-specific tumors. Lactate is a valuable fuel and potent signaling molecule that has now been implicated in multiple steps in tumorigenesis [e.g., driving vascular endothelial growth factor (VEGF) expression in normoxia]. Future work should utilize translational animal models to target tumors by altering the local tumor microenvironment, of which lactate is a critical part.

miR-142-3p inhibits aerobic glycolysis and cell proliferation in hepatocellular carcinoma via targeting LDHA

Cancer cells are addictively dependent on glycolysis even in an oxygen-rich condition. However, the mechanism underlying micro (mi)RNA regulation of aerobic glycolysis in cancer cells has not been fully understood. Here, we demonstrated that the expression of miR-142-3p was lower in hepatocellular carcinoma (HCC) as compared to adjacent non-tumor samples, which was confirmed in The Cancer Genome Atlas (TCGA) HCC cohorts and Gene Expression Omnibus (GEO) datasets. Function and pathway analysis showed that miR-142-3p was most relevent with metabolism. As predicted, the overexpression of miR-142-3p inhibited aerobic glycolysis and thus proliferation of HCC cells. Mechanistically, we identified lactate dehydrogenase A (LDHA), one of the important catalyticase for aerobic glycolysis, as the target of miR-142-3p. Exogenous expression of miR-142-3p reduced the protein levels of LDHA in both SK-Hep-1 and Huh7 cells. Dual luciferase report assays showed the expression of LDHA was directly modulated by miR-142-3p. miR-142-3p-induced deduction of aerobic glycolysis and proliferation were reversed by LDHA overexpression. Taken together, these results indicate that miR-142-3p could act as a tumor suppressor in HCC by targeting LDHA, suggesting new therapeutic targets for HCC treatment.

Src promotes EGF-induced epithelial-to-mesenchymal transition and migration in gastric cancer cells by upregulating ZEB1 and ZEB2 through AKT

Epithelial-to-mesenchymal transition (EMT) plays important roles in the migration, invasion, and metastasis of cancer cells. However, the role of Src in epidermal growth factor (EGF)-induced EMT and migration in gastric cancer cells remains to be clarified. In the current study, the effect of Src on EGF-stimulated EMT and migration was explored in gastric cancer cells. EGF induced EMT in gastric cancer cells and increased their migratory ability, which was accompanied by the phosphorylation of Src. PP2, the Src inhibitor, markedly suppressed EGF-mediated EMT and migration in gastric cancer cells. Additionally, EGF-stimulated upregulation of zinc finger E-box binding homeobox 1 (ZEB1) and zinc finger E-box binding homeobox 2 (ZEB2) was significantly repressed by PP2. Further analysis showed that EGF-stimulated phosphorylation of protein kinase B (AKT) was almost completely abolished by PP2, whereas that of extracellular signal-regulated kinase (ERK), signal transducer and activator of transcription 3 (STAT3) was only mildly suppressed. Moreover, LY294002, the AKT inhibitor, significantly inhibited EGF-induced upregulation of ZEB1 and ZEB2 as well as EMT and migration stimulated by EGF in gastric cancer cells. However, neither ERK inhibitor nor STAT3 inhibitor repressed EGF-induced EMT-related changes. Taken together, these results suggest that Src promotes EGF-stimulated EMT and migration by upregulation of ZEB1 and ZEB2 through AKT signaling pathway in gastric cancer cells.

Helicobacter pylori outer inflammatory protein A (OipA) suppresses apoptosis of AGS gastric cells in vitro

Outer inflammatory protein A (OipA) is an important virulence factor associated with gastric cancer and ulcer development; however, the results have not been well established and turned out to be controversial. This study aims to elucidate the role of OipA in Helicobacter pylori infection using clinical strains harbouring oipA "on" and "off" motifs. Proteomics analysis was performed on AGS cell pre-infection and postinfection with H. pylori oipA "on" and "off" strains, using liquid chromatography/mass spectrometry. AGS apoptosis and cell cycle assays were performed. Moreover, expression of vacuolating cytotoxin A (VacA) was screened using Western blotting. AGS proteins that have been suggested previously to play a role or associated with gastric disease were down-regulated postinfection with oipA "off" strains comparing to oipA "on" strains. Furthermore, oipA "off" and ΔoipA cause higher level of AGS cells apoptosis and G0/G1 cell-cycle arrest than oipA "on" strains. Interestingly, deletion of oipA increased bacterial VacA production. The capability of H. pylori to induce apoptosis and suppress expression of proteins having roles in human disease in the absence of oipA suggests that strains not expressing OipA may be less virulent or may even be protective against carcinogenesis compared those expressing OipA. This potentially explains the higher incidence of gastric cancer in East Asia where oipA "on" strains predominates.

Prognostic significance of the epithelial-mesenchymal transition factor zinc finger E-box-binding homeobox 2 in esophageal squamous cell carcinoma

Zinc finger E-box-binding homeobox 2 (ZEB2) has been reported to mediate epithelial-mesenchymal transition (EMT) and disease progression in several cancer types. However, the expression of ZEB2 in esophageal squamous cell carcinoma (OSCC) and its association with prognosis remains unclear. In the present study, a tissue microarray and immunohistochemistry were used to investigate ZEB2 and epithelial (E-)cadherin expression in OSCC tissues (n=218) and peritumoral esophageal tissues (POT; n=60). There was a significantly increased incidence of positive ZEB2 expression in OSCC tissues compared with the expression in POTs (P<0.012). By contrast, the incidence of positive E-cadherin expression in OSCC tissues was significantly decreased compared with the expression in POTs (P<0.004). ZEB2 expression in OSCC was associated with a number of clinicopathological factors, and it was also an independent predictive factor for shorter overall survival time (P<0.001). Overall, ZEB2 may promote OSCC metastasis and is a potential prognostic marker for malignancy.

MiR-200c inhibits bladder cancer progression by targeting lactate dehydrogenase A

Lactate dehydrogenase A (LDHA) is overexpressed in various cancers. We investigated LDHA expression and function in bladder cancer. We demonstrate that LDHA is up-regulated in bladder cancer cells and promotes proliferation, invasion, and glycolysis. Additionally, we found that microRNA (miR)-200c directly targets LDHA in bladder cancer cells. Ectopic expression of miR-200c inhibited LDHA-induced glycolysis, cell proliferation, and invasion. Thus, targeting LDHA through miR-200c is a potential therapeutic strategy in bladder cancer.

Prognostic significance of ZEB1 and ZEB2 in digestive cancers: a cohort-based analysis and secondary analysis

BACKGROUND

Digestive cancers are common malignancies worldwide, however there are few effective prognostic markers available. In this study we comprehensively investigated the prognostic significance of ZEB1 and ZEB2 in digestive cancers.

METHODS

Electronic databases were searched and studies met the selection criteria were included. Study information was recorded and quality assessment was performed according to the REMARK guideline. Hazard ratios and its corresponding 95% confidence intervals were extracted and pooled. Sensitivity analyses, subgroup analyses, cumulative meta-analyses and secondary analyses were also performed to increase the stability and reliability of our results.

RESULTS

24 cohort studies were included in the study. High ZEB1 and ZEB2 levels predicted poor overall survival, meanwhile high ZEB2 levels predicted poor disease free survival for digestive cancer patients. From subgroup analyses we observed ZEB1 was found to be significantly associated with poor overall survival for patients with pancreatic cancer, gastric cancer and colorectal cancer, while ZEB2 was found to be significantly associated with poor overall survival for patients with hepatocellular carcinoma and gastric cancer. Furthermore, by conducting secondary analyses we confirmed both ZEB1 and ZEB2 played important roles in gastric cancer prediction. In addition, we found high ZEB1 and ZEB2 expression were significantly associated with depth of invasion, lymph node metastasis and TNM stage in digestive cancer patients.

CONCLUSIONS

The present study validated the prognostic value and clinicopathological association of ZEB1 and ZEB2 in digestive cancers, especially in gastric cancer.

Pharmacological or genetic inhibition of LDHA reverses tumor progression of pediatric osteosarcoma

Reprogrammed energy metabolism is an emerging hallmark of cancer. Lactate dehydrogenase A (LDHA), a key enzyme involved in anaerobic glycolysis, is frequently deregulated in human malignancies. However, limited knowledge is known about its roles in the progression of osteosarcoma (OS). In this study, we found that LDHA is commonly upregulated in four OS cell lines compared with the normal osteoblast cells (hFOB1.19). Treatment with FX11, a specific inhibitor of LDHA, significantly reduced LDHA activity, and inhibited cell proliferation and invasive potential in a dose dependent manner. Genetic silencing of LDHA resulted in a decreased lactate level in the culture medium, reduced cell viability and decreased cell invasion ability. Meanwhile, silencing of LDHA also compromised tumorigenesis in vivo. Furthermore, knockdown of LDHA remarkably reduced extracellular acidification rate (ECAR) as well as glucose consumption. In the presence of 2-DG, a glycolysis inhibitor, LDHA-mediated cell proliferation and invasion were completely blocked, indicating the oncogenic activities of LDHA may dependent on Warburg effect. Finally, pharmacological inhibition of c-Myc or HIF1α significantly attenuated LDHA expression. Taken together, upregulated LDHA facilitates tumor progression of OS and might be a potential target for OS treatment.

Pyruvate Kinase M2 and Lactate Dehydrogenase A Are Overexpressed in Pancreatic Cancer and Correlate with Poor Outcome

Pancreatic cancer has a 5-year survival rate of less than 4%. Despite advances in diagnostic technology, pancreatic cancer continues to be diagnosed at a late and incurable stage. Accurate biomarkers for early diagnosis and to predict treatment response are urgently needed. Since alteration of glucose metabolism is one of the hallmarks of cancer cells, we proposed that pyruvate kinase type M2 (M2PK) and lactate dehydrogenase A (LDHA) enzymes could represent novel diagnostic markers and potential therapeutic targets in pancreatic cancer. In 266 tissue sections from normal pancreas, pancreatic cystic neoplasms, pancreatic intraepithelial neoplasia (PanIN) and cancer, we evaluated the expression of PKM2, LDHA, Ki-67 and CD8+ by immunohistochemistry and correlated these markers with clinicopathological characteristics and patient survival. PKM2 and LDHA expression was also assessed by Western blot in 10 human pancreatic cancer cell lines. PKM2 expression increased progressively from cyst through PanIN to cancer, whereas LDHA was overexpressed throughout the carcinogenic process. All but one cell line showed high expression of both proteins. Patients with strong PKM2 and LDHA expression had significantly worse survival than those with weak PKM2 and/or LDHA expression (7.0 months vs. 27.9 months, respectively, p = 0.003, log rank test). The expression of both PKM2 and LDHA correlated directly with Ki-67 expression, and inversely with intratumoral CD8+ cell count. PKM2 was significantly overexpressed in poorly differentiated tumours and both PKM2 and LDHA were overexpressed in larger tumours. Multivariable analysis showed that combined expression of PKM2 and LDHA was an independent poor prognostic marker for survival. In conclusion, our results demonstrate a high expression pattern of two major glycolytic enzymes during pancreatic carcinogenesis, with increased expression in aggressive tumours and a significant adverse effect on survival.