Levels Of Lactate Dehydrogenase A Research Articles

Evaluation of Serum Pyruvate Kinase M2 and Key Glycolytic Signatures and Its Correlation with Phosphatidylinositol-3-kinase/Akt/Mammalian Target of Rapamycin Pathway in Women with Breast Carcinoma

Abstract Background: A desired target for cancer therapy is a cancer-specific metabolism which is associated with innate or acquired therapeutic resistance, malignancies, and aggressive cancer growth. Nevertheless, these cells utilize manifold metabolic routes to prolong their mass explosion. Human hexokinase 2 (HK2), phosphofructokinase, muscle (PFKM), pyruvate kinase M2 (PKM2), and lactate dehydrogenase A (LDHA) are fundamental signature players of cancer glycolysis playing a role in cancer cell regulation. Reflecting their metabolic roles may be possible with a better grasp of the metabolism transition in the early onset and spread of cancer. This study was designed to assess the serum protein levels of HK2, PFKM, PKM2, and LDHA in women with breast carcinoma and its correlation with phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) pathway. Methods: In the current research, case–control investigation was undertaken with breast cancer women (n = 30) and compatible healthy women (n = 30) visiting Justice K. S. Hegde Charitable Hospital, Deralakatte, Mangaluru, who were selected on the basis of inclusion and exclusion criteria. Baseline characteristics for the study population were marked down. The HK2, PFKM, PKM2, and LDHA levels within serum were estimated by means of sandwich enzyme-linked immunosorbent assay. Results: We observed a difference that was significant among the two groups with regard to age and postmenopausal status and also a difference in first-degree family history. The levels of PKM2 and key glycolytic enzymes in serum varied between the case and control groups. There was a positive correlation that was observed in breast carcinoma subjects with glycolytic proteins and signaling pathway (PI3K/Akt/mTOR). Conclusions: Nevertheless, assured processes that persuade the target enzymes remain vague and require further in-depth exploration. Overall, discovering anticancer therapeutics that target glycolytic enzymes involved in glucose metabolism remains a dilemma.

Glucose transporter 3 (GLUT3) promotes lactylation modifications by regulating lactate dehydrogenase A (LDHA) in gastric cancer

ObjectivesGlucose transporter 3 (GLUT3) plays a major role in glycolysis and glucose metabolism in cancer cells. We aimed to investigate the correlation between GLUT3 and histone lactylation modification in the occurrence and progression of gastric cancer.Materials and methodsWe initially used single-cell sequencing data to determine the expression levels of GLUT3 and lactate dehydrogenase A (LDHA) in primary tumor, tumor-adjacent normal, and metastasis tumor tissues. Immunohistochemistry analysis was conducted to measure GLUT3, LDHA, and L-lactyl levels in gastric normal and cancer tissues. Transwell and scratch assays were performed to evaluate the metastatic and invasive capacity of gastric cancer cell lines. Western blotting was used to measure L-lactyl and histone lactylation levels in gastric cancer cell lines.ResultsSingle-cell sequencing data showed that GLUT3 expression was significantly increased in primary tumor and metastasis tumor tissues. In addition, GLUT3 expression was positively correlated with that of LDHA expression and lactylation-related pathways. Western blotting and immunohistochemistry analyses revealed that GLUT3 was highly expressed in gastric cancer tissues and cell lines. GLUT3 knockdown in gastric cancer cell lines inhibited their metastatic and invasive capacity to various degrees. Additionally, the levels of LDHA, L-lactyl, H3K9, H3K18, and H3K56 significantly decreased after GLUT3 knockdown, indicating that GLUT3 affects lactylation in gastric cancer cells. Moreover, LDHA overexpression in a GLUT3 knockdown cell line reversed the levels of lactylation and EMT-related markers, and the EMT functional phenotype induced by GLUT3 knockdown. The in vivo results were consistent with the in vitro results.ConclusionsThis study suggests the important role of histone lactylation in the occurrence and progression of gastric cancer, and GLUT3 may be a new diagnostic marker and therapeutic target for gastric cancer.

Investigation of mRNA Levels of PFK-1, LDH-A, p53, and HIF-1α Genes Involved in Metabolic Reprogramming in Non-small Cell Lung Carcinoma

Background: It is expected that the expression of key enzymes of the glycolysis pathway, specially PFK-1, increases tumor cells and so enhances the function of this pathway. The p53 and HIF-1 proteins are regulators of the expression of PFK-1 and LDH enzymes. This study was performed to investigate changes in the expression of PFK-1, LDH-A, p53, and HIF-1α genes to identify metabolic changes in non-small cell lung carcinoma (NSCLC) samples. Methods: A number of 30 tumors and their adjacent normal tissue samples from surgically approved NSCLC patients were used. Total RNA from each tissue was extracted. The changes in mRNA levels of PFK-1M, LDHA, p53, and hypoxia-inducible factor-1 (HIF-1α) genes were evaluated in tumor and normal tissues of all patients using the real-time polymerase chain reaction (PCR) method. Finally, statistical analysis was used to determine significant differences and the relationship between changes in mRNA levels. Results: According to the results, there was no significant difference in the mRNA levels of these genes between tumor and normal tissues. A significant difference in the mRNA level of lactate dehydrogenase A (LDHA) between adenocarcinoma (AdC) and squamous cell carcinoma (SqCC) tumor types was observed (P=0.014). Also, the difference between the mRNA level of LDHA and HIF-1α in metastatic and non-metastatic samples was significant (P=0.035 and P=0.046 respectively). Age and male gender were directly associated with an increased risk of NSCLC. Conclusion: The results of the present study revealed that the increase in mRNA level of PFK-1 and p53 may be involved in NSCLC initiation, and an increase in LDH-A and HIF-1a is associated with a metastatic phenotype.

The function of lactate dehydrogenase A in retinal neurons: implications to retinal degenerative diseases.

The postmitotic retina is highly metabolic and the photoreceptors depend on aerobic glycolysis for an energy source and cellular anabolic activities. Lactate dehydrogenase A (LDHA) is a key enzyme in aerobic glycolysis, which converts pyruvate to lactate. Here we show that cell-type-specific actively translating mRNA purification by translating ribosome affinity purification shows a predominant expression of LDHA in rods and cones and LDHB in the retinal pigment epithelium and Müller cells. We show that genetic ablation of LDHA in the retina resulted in diminished visual function, loss of structure, and a loss of dorsal-ventral patterning of the cone-opsin gradient. Loss of LDHA in the retina resulted in increased glucose availability, promoted oxidative phosphorylation, and upregulated the expression of glutamine synthetase (GS), a neuron survival factor. However, lacking LDHA in Müller cells does not affect visual function in mice. Glucose shortage is associated with retinal diseases, such as age-related macular degeneration (AMD), and regulating the levels of LDHA may have therapeutic relevance. These data demonstrate the unique and unexplored roles of LDHA in the maintenance of a healthy retina.

LDHA induces EMT gene transcription and regulates autophagy to promote the metastasis and tumorigenesis of papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is one of the most common kinds of endocrine-related cancer and has a heterogeneous prognosis. Metabolic reprogramming is one of the hallmarks of cancers. Aberrant glucose metabolism is associated with malignant biological behavior. However, the functions and mechanisms of glucose metabolism genes in PTC are not fully understood. Thus, data from The Cancer Genome Atlas database were analyzed, and lactate dehydrogenase A (LDHA) was determined to be a potential novel diagnostic and therapeutic target for PTCs. The research objective was to investigate the expression of LDHA in PTCs and to explore the main functions and relative mechanisms of LDHA in PTCs. Higher expression levels of LDHA were found in PTC tissues than in normal thyroid tissues at both the mRNA and protein levels. Higher expression levels of LDHA were correlated with aggressive clinicopathological features and poor prognosis. Moreover, we found that LDHA not only promoted PTC migration and invasion but also enhanced tumor growth both in vitro and in vivo. In addition, we revealed that the metabolic products of LDHA catalyzed induced the epithelial–mesenchymal transition process by increasing the relative gene H3K27 acetylation. Moreover, LDHA knockdown activated the AMPK pathway and induced protective autophagy. An autophagy inhibitor significantly enhanced the antitumor effect of FX11. These results suggested that LDHA enhanced the cell metastasis and proliferation of PTCs and may therefore become a potential therapeutic target for PTCs.

Lactate Dehydrogenase A as a Potential New Biomarker for Thyroid Cancer.

BackgroundSeveral cancers show increased levels of lactate dehydrogenase A (LDHA), which are associated with cancer progression. However, it remains unclear whether LDHA levels are associated with papillary thyroid cancer (PTC) aggressiveness or with the presence of the PTC prognostic marker, the BRAFV600E mutation. This study aimed to evaluate the potential of LDHA as a PTC prognostic marker.MethodsLDHA expression was examined in 83 PTC tissue specimens by immunohistochemistry. Human thyroid cell lines were genetically manipulated to overexpress BRAFV600E or were treated with a BRAF-specific short hairpin RNA (shBRAF), whose effects on LDHA expression were evaluated by Western blotting. Data from 465 PTC patients were obtained from The Cancer Genome Atlas (TCGA) database and analyzed to validate the in vitro results.ResultsLDHA was aberrantly overexpressed in PTC. Intense immunostaining for LDHA was observed in PTC specimens carrying mutated BRAF, whereas the intensity was less in wild-type BRAF samples. Overexpression of BRAFV600E resulted in LDHA upregulation, whereas treatment with shBRAF downregulated LDHA in human thyroid cell lines. Furthermore, LDHA mRNA expression was significantly elevated and associated with BRAFV600E expression in thyroid cancer tissues from TCGA database. Additionally, LDHA overexpression was found to be correlated with aggressive clinical features of PTC, such as lymph node metastases and advanced tumor stages.ConclusionLDHA overexpression is associated with the BRAFV600E mutation and an aggressive PTC behavior. Therefore, LDHA may serve as a biomarker and therapeutic target in PTC.

ANXA2P2/miR-9/LDHA axis regulates Warburg effect and affects glioblastoma proliferation and apoptosis

BackgroundAerobic glycolysis is a unique tumor cell phenotype considered as one of the hallmarks of cancer. Aerobic glycolysis can accelerate tumor development by increasing glucose uptake and lactate production. In the present study, lactate dehydrogenase A (LDHA) is significantly increased within glioma tissue samples and cells, further confirming the oncogenic role of LDHA within glioma. MethodsHematoxylin and eosin (H&E) and immunohistochemical (IHC) staining were applied for histopathological examination. The protein levels of LDHA, transporter isoform 1 (GLUT1), hexokinase 2 (HK2), phosphofructokinase (PFK) in target cells were detected by Immunoblotting. The predicted miR-9 binding to lncRNA Annexin A2 Pseudogene 2 (ANXA2P2) or the 3′ untranslated region (UTR) of LDHA was verified using Luciferase reporter assay. Cell viability or apoptosis were examined by MTT assay or Flow cytometry. Intracellular glucose and Lactate levels were measured using glucose assay kit and lactate colorimetric assay kit. ResultsThe expression of ANXA2P2 showed to be dramatically upregulated within glioma tissue samples and cells. Knocking down ANXA2P2 within glioma cells significantly inhibited cell proliferation and aerobic glycolysis, as manifested as decreased lactate and increased glucose in culture medium, and downregulated protein levels of glycolysis markers, GLUT1, HK2, PFK, as well as LDHA. miR-9 was predicted to target both lncRNA ANXA2P2 and LDHA. The overexpression of miR-9 suppressed the cell proliferation and aerobic glycolysis of glioma cells. Notably, miR-9 could directly bind to LDHA 3′UTR to inhibit LDHA expression and decrease the protein levels of LDHA. ANXA2P2 competitively targeted miR-9, therefore counteracting miR-9-mediated repression on LDHA. Within tissues, miR-9 exhibited a negative correlation with ANXA2P2 and LDHA, respectively, whereas ANXA2P2 and LDHA exhibited a positive correlation with each other. ConclusionsIn conclusion, ANXA2P2/miR-9/LDHA axis modulates the aerobic glycolysis progression in glioma cells, therefore affecting glioma cell proliferation.

The Warburg effect and tumour immune microenvironment in extramammary Paget's disease: overexpression of lactate dehydrogenase A correlates with immune resistance.

Extramammary Paget's disease (EMPD) is a rare malignant skin cancer. One of the hallmarks of cancers, including EMPD, is an enhancement of aerobic glycolysis, which is also known as the Warburg effect. In the last step of glycolysis, the enzyme lactate dehydrogenase A (LDHA) catalyzes the conversion of pyruvate to lactic acid, the accumulation of which contributes to the creation of an acidic tumour microenvironment. This in turn results in immunosuppression in various types of cancers. However, the contribution of these pathways has not been well-studied in EMPD. To investigate the significance of the Warburg effect and its contribution to the tumour immune microenvironment in EMPD. The mRNA expression levels of molecules involved in glycolysis and immune-related cytokines were examined by ddPCR. The number of immune cells was assessed by immunohistochemistry (IHC). The levels of two glycolytic enzymes, HK2 and LDHA, in tumour tissues were significantly increased compared to those in paired-normal tissues. IHC analyses revealed increased numbers of PD-L1+ , PD-1+ , CD163+ M2 macrophages, Iba1+ macrophages and Foxp3+ Tregs that were associated with high LDHA levels in EMPD. ddPCR demonstrated that multiple cytokines including IL-4, IL-6, IL-10, TGF-β and CCL-2 were upregulated and associated with high LDHA levels in EMPD. Statistical analyses showed that IL-6 mRNA expression correlated with the number of CD163+ , Iba-1+ and Foxp3+ cells. The Warburg effect contributes to immunomodulation in the tumour microenvironment and further elucidation may lead to better understanding of the pathogenesis of EMPD.

MiR-33b inhibits osteosarcoma cell proliferation through suppression of glycolysis by targeting Lactate Dehydrogenase A (LDHA)

Osteosarcoma (OS) is one of the most common types of malignant bone tumor in adolescent. MicroRNAs (miRNAs) are widely studied regulatory molecules which play important roles in tumor development, differentiation, growth, invasion, chemosensitivity and cellular metabolism. Recently, miR-33b has been reported to act as a tumor suppressor in osteosarcoma. However, the detailed mechanism of miR-33b in regulating osteosarcoma cell proliferation remains unclear. In this study, we detected miR-33b was significantly downregulated in osteosarcoma tissues compared to their matched adjacent nontumor tissues. The decreased expressions of miR-33b were also found in multiple osteosarcoma cell lines, including MG63, Saos-2, U2OS and SOSP-9607 when compared to normal osteoblast cell line hFOB. Overexpression of miR-33b suppressed U2OS cell proliferation and anaerobic glycolysis. We identified Lactate dehydrogenase-A (LDHA) as a direct target of miR-33b in osteosarcoma tumors and cells by Western blot and luciferase assay. Moreover, inhibition of LDHA significantly suppressed glycolysis and cell proliferation of osteosarcoma cells. Restoration of LDHA in miR-33b-overexpressing osteosarcoma cells reversed the suppressive effect of miR-33b on cell proliferation. In addition, we report a significantly negative correlation between LDHA mRNA and miR-33b expression in osteosarcoma tumors: miR-33b is downregulated in OS tumors with high levels of LDHA (92.9%). Meanwhile, high miR-33b expressions were found majorly in OS tumors with low LDHA mRNA levels (82.4%). This study reveals that miR-33b plays a suppressive role in the regulation of osteosarcoma cell proliferation through direct targeting LDHA. The miR-33b/glycolysis/LDHA axis may contribute to development of therapeutic anti-tumor agents for osteosarcoma.

MiR-323a-3p suppressed the glycolysis of osteosarcoma via targeting LDHA.

Accumulating evidence has demonstrated that there is critical involvement of miRNAs in the initiation and progression of cancers. Here, we showed that miR-323a-3p was significantly down-regulated in osteosarcoma (OS) tissues and cell lines. Overexpression of miR-323a-3p decreased the cell viability, colon formation and induced the apoptosis of OS cells. Using bioinformatics analysis, lactate dehydrogenase A (LDHA) was predicted as one of the down-steam targets of miR-323a-3p. Highly expressed miR-323a-3p significantly decreased both the mRNA and protein levels of LDHA. Inverse correlation between the expression of LDHA and miR-323a-3p was observed in OS tissues. Consistent with the function of LDHA in glycolysis of cancer cells, overexpression of miR-323a-3p attenuated the lactate production of OS cells. These results demonstrated that miR-323a-3p suppressed the growth of OS cells via targeting LDHA and inhibited the glycolysis of OS. This study provides insight into the molecular mechanism of miR-323a-3p in regulating OS.

Silencing LDHA inhibits proliferation, induces apoptosis and increases chemosensitivity to temozolomide in glioma cells.

Glioblastoma multiforme (GBM) is a prevalent and aggressive disease, and the development of a novel therapy to better treat advanced GBM is urgently required. Lactate dehydrogenase A (LDHA), which functions as a key enzyme in transforming pyruvate into lactate, has attracted more attention in recent years due to its critical role in various types of advanced cancer. Previous data derived from the Oncomine database have shown that the expression of LDHA is higher in GBM tissues than that in corresponding normal control tissues. However, the association of LDHA levels with glioma clinical grades and the possible mechanisms of LDHA in GBM progression have not been investigated. The present study showed that there is a significant positive correlation between LDHA expression levels and tumor clinical stages. The knockdown of LDHA inhibited cell growth by inhibiting cell cycle progression and inducing apoptosis in glioma cell lines. Upon investigating the molecular mechanism, LDHA knockdown via siRNA treatment was associated with decreased cyclin D1 expression, increased cleavage of PARP, and altered B-cell lymphoma 2 and B-cell lymphoma 2-associated protein X expression. In addition, LDHA knockdown led to the marked downregulation of matrix metalloproteinase (MMP)-2, MMP-9, VE-Cadherin and vascular endothelial growth factor expression levels. Furthermore, knock down of LDHA enhanced the chemosensitivity of glioma cells to temozolomide (TMZ), a second-generation alkylating agent with activity against recurrent high-grade glioma. These findings support LDHA as a novel target for developing effective therapeutic strategies to treat GBM.

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.

Honokiol enhanced the antitumor activity of Sorafenib through inhibiting glycolysis

Objective To investigate the synergetic inhibitory effects of Honokiol and Sorafenib on hepatocellular carcinoma cell line HepG2 in vitro. Methods The expression of lactate dehydrogenase A (LDHA) in liver cancer tissue was detected by immunohistochemistry (IHC), the glycolysis level was evaluated by detecting the expression of LDHA in tumor cells and the level of lactate in the culture supernatants by immunofluorescence (IF) and colorimetry, respectively. The inhibitory effect of honokiol combined with sorafenib on growth of tumor cells was tested by methyl thiazol tetrazolium (MTT) and clonogenic assays, and apoptosis was examined by annexin V staining and caspase-3 activity detecting. Results LDHA expression increased in hepatocellular carcinoma as compared with normal liver tissues (3.74±0.98 vs. 1.92±0.63) (P=0.024). Treatment with 2.5 μmol/L Sorafenib for 2 days induced enhancement of aerobic glycolysis, reflecting by an increased levels of LDHA in cells and lactate in cell supernatants [from (17.23±3.42) mmol/L to (28.34±8.19) mmol/L](P=0.001). As compared with Sorafenib monotherapy, the significant reduction of cell growth rate [(74.35±13.64)% vs. (38.16±5.75)%](P=0.008) and increase of apoptosis rate (47% vs. 18%) (P=0.029) were observed in the tumor cells treated with Sorafenib plus Honokiol. Conclusion Honokiol enhances the killing effect of Sorafenib on hepatoma cell line HepG2, which may be related to the inhibition of tumor cell glycolysis and induction of apoptosis. Key words: Carcinoma, hepatocellular; Sorafenib; Lactate dehydrogenase A; Glycolysis; Honokiol

Sirtuin 6 attenuates periapical lesion propagation by modulating hypoxia-induced chemokine (C-C motif) ligand 2 production in osteoblasts.

To investigate the attenuating effect of sirtuin 6 (SIRT6) on hypoxia-induced production of chemokine (C-C motif) ligand 2 (CCL2) by osteoblasts and the relevance of this action on the pathogenesis of periapical lesions. Sirtuin 6 was overexpressed in MC3T3-E1 murine osteoblasts by lentivirus-mediated gene transfer. The relationship between the antiglycolytic/antioxidative activities of SIRT6 and its effect on hypoxia-induced CCL2 production were examined. Pathogenetic relevance of the actions of SIRT6 was assessed in a rat model of induced apical periodontitis. The data were analysed statistically using Student's t-test or one-way analysis of variance (anova) and then a Tukey's multiple comparison test. In cultured murine osteoblasts, 24-h hypoxic treatment significantly enhanced the generation of reactive oxygen species (P=0.003), expression of lactate dehydrogenase A (LDHA) and production of lactate (P=0.007). A reciprocal effect between hypoxia-induced redox imbalance and hypoxia-enhanced glycolysis was noted which in turn augmented the secretion of CCL2. Through its antiglycolytic and antioxidative effects, SIRT6 blocked the vicious cycle to suppress CCL2 production. In normal periapical tissues of rats, strong expression of SIRT6 and low levels of LDHA and 8-OHdG (a marker of oxidative DNA damage) were found in osteoblasts. In induced apical periodontitis, osteoblastic expression of SIRT6 was significantly suppressed (P=0.001) which was associated with significantly elevated levels of LDHA (P=0.003) and 8-OHdG (P=0.004) and significantly enhanced recruitment of macrophages (P=0.004). Sirtuin 6 has a therapeutic effect on periapical lesions through suppression of CCL2 synthesis. The anti-inflammatory action of SIRT6 is closely related to its regulatory activities in cellular metabolism and redox homoeostasis.

High expressions of LDHA and AMPK as prognostic biomarkers for breast cancer

ObjectivesThe purpose of this study was to investigate the potential correlation between lactate dehydrogenase A (LDHA) and AMP-activated protein kinase (AMPK) and their clinicopathologic significance in breast cancer. Materials and MethodsWestern blot and qRT-PCR were used to detect the expression levels of LDHA and AMPK in eight breast cancer lines and eight breast cancer tissues. In addition, LDHA and AMPK were detected by immunohistochemistry (IHC) using breast cancer tissue microarrays (TMAs) of 112 patients. The association between LDHA and AMPK expression levels was statistically analyzed. So were the prognostic roles and clinicopathologic significances in breast cancer. ResultsThe expression levels of LDHA and AMPK were relatively higher in triple-negative breast cancer (TNBC) cell lines than in non-triple-negative breast cancer (NTNBC) cell lines. LDHA and AMPK were also further up-regulated in TNBC tissues than in NTNBC tissues. Correlation analysis showed a positive correlation between LDHA and AMPK expression levels. Expression of LDHA and AMPK were significantly correlated with TNM stage, distant metastasis, Ki67 status and survival outcomes of patients. Patients with both positive expression of LDHA and AMPK showed shorter overall survival (OS) and disease-free survival (DFS). ConclusionsThese findings improve our understanding of the expression pattern of LDHA and AMPK in breast cancer and clarify the role of LDHA and AMPK as promising prognostic biomarkers for breast cancer.

MiR-410 enhanced hESC-derived pancreatic endoderm transplant to alleviate gestational diabetes mellitus.

Gestational diabetes mellitus (GDM) is a condition commonly encountered during mid to late pregnancy with pathologic manifestations including hyperglycemia, hyperinsulinemia, insulin resistance, and fetal mal-development. The deficit and dysfunction of insulin secreting β-cells are signature symptoms for GDM. Pancreatic progenitors derived from human embryonic stem cells (hESCs) were shown to be able to effectively treat diabetes in mice. In this study, we first identified that microRNA-410 (miR-410) directly targets lactate dehydrogenase A (LDHA), a gene selectively repressed in normal insulin secreting β-cells. hESCs that can be induced to express miR-410 hence keeping LDHA levels in check were then differentiated in vitro into pancreatic endoderm, followed by transplantation into db/+ mouse model of GDM. The transplant greatly improved glucose metabolism and reproductive outcome of the pregnant females suffering from GDM. Our findings describe for the first time the method of combining miRNA with hESCs, providing proof of concept by employing genetically modified stem cell therapy for treating GDM.

Lactate dehydrogenase A negatively regulated by miRNAs promotes aerobic glycolysis and is increased in colorectal cancer.

Reprogramming metabolism of tumor cells is a hallmark of cancer. Lactate dehydrogenase A (LDHA) is frequently overexpressed in tumor cells. Previous studies has shown higher levels of LDHA is related with colorectal cancer (CRC), but its role in tumor maintenance and underlying molecular mechanisms has not been established. Here, we investigated miRNAs-induced changes in LDHA expression. We reported that colorectal cancer express higher levels of LDHA compared with adjacent normal tissue. Knockdown of LDHA resulted in decreased lactate and ATP production, and glucose uptake. Colorectal cancer cells with knockdown of LDHA had much slower growth rate than control cells. Furthermore, we found that miR-34a, miR-34c, miR-369-3p, miR-374a, and miR-4524a/b target LDHA and regulate glycolysis in cancer cells. There is a negative correlation between these miRNAs and LDHA expression in colorectal cancer tissues. More importantly, we identified a genetic loci newly associated with increased colorectal cancer progression, rs18407893 at 11p15.4 (in 3'-UTR of LDHA), which maps to the seed sequence recognized by miR-374a. Cancer cells overexpressed miR-374a has decreased levels of LDHA compared with miR-374a-MUT (rs18407893 at 11p15.4). Taken together, these novel findings provide more therapeutic approaches to the Warburg effect and therapeutic targets of cancer energy metabolism.

Synergistic cytotoxicity of cisplatin and Taxol in overcoming Taxol resistance through the inhibition of LDHA in oral squamous cell carcinoma.

The development of chemoresistance in patients represents a major challenge in cancer treatment. Lactate dehydrogenase-A (LDHA) is one of the principle isoforms of LDH that is expressed in breast tissue, controlling the conversion of pyruvate to lactate and also playing a significant role in the metabolism of glucose. The aim of this study was to identify whether LDHA was involved in oral cancer cell resistance to Taxol and whether the downregulation of LDHA, as a result of cisplatin treatment, may overcome Taxol resistance in human oral squamous cells. The OECM-1 oral epidermal carcinoma cell line was used, which has been widely used as a model of oral cancer in previous studies. The role of LDHA in Taxol and cisplatin resistance were investigated and the synergistic cytotoxicity of cisplatin and/or Taxol in oral squamous cells was analyzed. Cell viability was analyzed by MTT assay, LDHA expression was analyzed by western blot analysis and siRNA tranfection was performed to knock down LDHA expression. The present study results showed that decreased levels of LDHA were responsible for the resistance of oral cancer cells to cisplatin (CDDP). CDDP treatments downregulated LDHA expression, and lower levels of LDHA were detected in the CDDP-resistant oral cancer cells compared with the CDDP-sensitive cells. By contrast, the Taxol-resistant cancer cells showed elevated LDHA expression levels. In addition, small interfering RNA-knockdown of LDHA sensitized the cells to Taxol, but desensitized them to CDDP treatment, while exogenous expression of LDHA sensitized the cells to CDDP, but desensitized them to Taxol. The present study also revealed the synergistic cytotoxicity of CDDP and Taxol for killing oral cancer cells through the inhibition of LDHA. This study highlights LDHA as a novel therapeutic target for overcoming Taxol resistance in oral cancer patients using the combined treatments of Taxol and CDDP.

LDH-A Acetylation: Implication in Cancer

LDH-A Acetylation: Implication in Cancer

Omission of dry period or milking once daily affects metabolic status and is reflected by mRNA levels of enzymes in liver and muscle of dairy cows

The objective of this study was to study the mRNA expression of bovine hepatic and muscular genes according to metabolic status in early lactation influenced by different milking regimes. Control-cows (C, n=12) were dried off 56 days before calving and were milked twice daily after parturition. Cows milked once daily (ODM, n=12) were dried off similarly to the C-cows, but were milked only once daily during the first four weeks of lactation. Continuously milked cows (CM, n=12) were milked twice daily throughout the gestation–lactation cycle. Muscle biopsies were obtained within 24h after calving and at weeks 6 and 16 post partum (pp). Liver biopsies were performed one week before parturition, within 24h after calving and at weeks 2, 4, and 8 pp. Muscle samples were analyzed for the mRNA abundance of the facilitated glucose transporter, members 1 and 4 (SLC2A1, SLC2A4), the insulin receptor (INSR), lactate dehydrogenase A (LDHA), acyl-CoA dehydrogenase very long chain (ACADVL), enoyl CoA hydratase (ECHS1), and actin alpha 1 (ACTA1). Liver samples were examined for the mRNA abundance of facilitated glucose transporter, member 2 (SLC2A2), carnitine palmitoyltransferase 1A (CPT1A), acyl-CoA dehydrogenase very long chain (ACADVL), glycerol-3-phosphate acyltransferase (GPAM), phosphoenolpyruvate carboxykinase 2 (PCK2), citrate synthase (CS), tyrosine aminotransferase (TAT) and cathepsin L1 (CTSL). In skeletal muscle, transcript abundances of INSR and SLC2A1 were not affected by treatment, whereas SLC2A4 mRNA expression tended to be lower in CM-cows in comparison with C-cows (P=0.07) and ODM-cows (P=0.09). Muscular mRNA levels of LDHA, ACADVL and ACTA1 were not affected by the milking regimen. ECHS1 was down-regulated in CM-cows compared to C-cows (P=0.0009) and in tendency compared to OD-cows (P=0.08). All genes, except ECHS1, were strongly influenced by the sampling time point. In liver samples, metabolic status was reflected by marked changes in various mRNA levels. In CM-cows, higher CPT1A and PCK2 transcript abundances were found compared to C- (P<0.10) and ODM-cows (P<0.05). GPAM-mRNA levels were lowest in ODM cows (P=0.09 and P=0.0003 for comparison with C and CM-cows, respectively). The abundance of CTSL was lowest in C-cows compared with both remaining groups (P<0.05). Additionally, GLUT2, ACADvl, CPT1A, GPAM and PEPCK2 abundances differed between sampling time points.This shows that the improved metabolism was also reflected by changes in muscular and hepatic expression of some key enzymes particularly in CM-cows.