Lactate dehydrogenase B: a metabolic marker of response to neoadjuvant chemotherapy in breast cancer

Hollow Nanoneedle-Electroporation System To Extract Intracellular Protein Repetitively and Nondestructively

Techniques used to understand the dynamic expression of intracellular proteins are critical in both fundamental biological research and biomedical engineering. Various methods for analyzing proteins have been developed, but these methods require the extraction of intracellular proteins from the cells resulting in cell lysis and subsequent protein purifications from the lysate, which limits the potential of repetitive extraction from the same set of viable cells to track dynamic intracellular protein expression. Therefore, it is crucial to develop novel methods that enable nondestructive and repeated extraction of intracellular proteins. This work reports a hollow nanoneedle-electroporation system for the repeated extraction of intracellular proteins from living cells. Hollow nanoneedles with ∼450 nm diameter were fabricated by a material deposition and etching process, followed by integration with a microfluidic device. Long-lasting electrical pulses were coupled with the nanoneedles to permeate the cell membrane, allowing intracellular contents to diffuse into the microfluidic channels located below the cells via hollow nanoneedles. Using lactate dehydrogenase B (LDHB) as the model intracellular protein, the nanoneedle-electroporation system effectively and repeatedly extracted LDHB from the same set of cells at different time points, followed by quantitative analysis of LDHB via standard enzyme-linked immunosorbent assay. Our work demonstrated an efficient method to nondestructively probe intracellular protein levels and monitor the dynamic protein expression, with great potential to help understanding cell behaviors and functions.

Investigation of the molecular mechanisms of hepatic injury upon naphthalene exposure in zebrafish (Danio rerio)

Naphthalene has been used worldwide as a commercial insecticide for decades, which when detected in the environment can have various negative effects on non-target organism, such as hepatotoxicity. However, the molecular mechanisms of how naphthalene acts to affect the liver in zebrafish (Danio rerio) remains unknown. In this study, we evaluated the potential toxic effects of naphthalene on livers in female adult zebrafish over a 21-day subacute exposure. Global hepatic gene expression was examined by microarrays and the results indicated the regulated genes were associated significantly with vital hepatic injury pathways and GO categories upon naphthalene exposure, such as disruptions in lipid metabolism, inflammatory response, and the carcinogenic processes. According to our observations of liver histology, nuclear enlargement as a potential indicator of cancers and hepatic lipometabolic disorder precisely were supported. The 96 h acute naphthalene tests on Tg(lysC:DsRed) and LiPan lines larvae revealed recruitment of neutrophils by the liver, as well as decreased liver size, which further confirmed hepatic inflammation response to naphthalene exposure. Thus, these findings advance the field of ecotoxicology by unveiling a new role of naphthalene as a leading cause of liver damage and provide potential biomarker-genes for environmental naphthalene monitoring.

Aberrant FGFR Tyrosine Kinase Signaling Enhances the Warburg Effect by Reprogramming LDH Isoform Expression and Activity in Prostate Cancer

The acquisition of ectopic fibroblast growthfactor receptor 1 (FGFR1) expression is well documented in prostate cancer progression. How it contributes to prostate cancer progression is not fully understood, although it is known to confer a growth advantage and promote cell survival. Here, we report that FGFR1 tyrosine kinase reprograms the energy metabolism of prostate cancer cells by regulating the expression of lactate dehydrogenase (LDH) isozymes. FGFR1 increased LDHA stability through tyrosine phosphorylation and reduced LDHB expression by promoting its promoter methylation, thereby shifting cell metabolism from oxidative phosphorylation to aerobic glycolysis. LDHA depletion compromised, whereas LDHB depletion enhanced the tumorigenicity of prostate cancer cells. Furthermore, FGFR1 overexpression and aberrant LDH isozyme expression were associated with short overall survival and biochemical recurrence times in patients with prostate cancer. Our results indicate that ectopic FGFR1 expression reprograms the energy metabolism of prostate cancer cells, representing a hallmark change in prostate cancer progression.Significance: FGF signaling drives the Warburg effect through differential regulation of LDHA and LDHB, thereby promoting the progression of prostate cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/16/4459/F1.large.jpg Cancer Res; 78(16); 4459-70. ©2018 AACR.

Comprehensive landscape of subtype-specific coding and non-coding RNA transcripts in breast cancer

Molecular classification of breast cancer into clinically relevant subtypes helps improve prognosis and adjuvant-treatment decisions. The aim of this study is to provide a better characterization of the molecular subtypes by providing a comprehensive landscape of subtype-specific isoforms including coding, long non-coding RNA and microRNA transcripts. Isoform-level expression of all coding and non-coding RNAs is estimated from RNA-sequence data of 1168 breast samples obtained from The Cancer Genome Atlas (TCGA) project. We then search the whole transcriptome systematically for subtype-specific isoforms using a novel algorithm based on a robust quasi-Poisson model. We discover 5451 isoforms specific to single subtypes. A total of 27% of the subtype-specific isoforms have better accuracy in classifying the intrinsic subtypes than that of their corresponding genes. We find three subtype-specific miRNA and 707 subtype-specific long non-coding RNAs. The isoforms from long non-coding RNAs also show high performance for separation between Luminal A and Luminal B subtypes with an AUC of 0.97 in the discovery set and 0.90 in the validation set. In addition, we discover 1500 isoforms preferentially co-expressed in two subtypes, including 369 isoforms co-expressed in both Normal-like and Basal subtypes, which are commonly considered to have distinct ER-receptor status. Finally, analyses at protein level reveal four subtype-specific proteins and two subtype co-expression proteins that successfully validate results from the isoform level.

Identification of key pathways and genes in response to trastuzumab treatment in breast cancer using bioinformatics analysis

Breast cancer (BC) is one of the leading causes of death among women worldwide. The gene expression profile GSE22358 was downloaded from the Gene Expression Omnibus (GEO) database, which included 154 operable early-stage breast cancer samples treated with neoadjuvant capecitabine plus docetaxel, with (34) or without trastuzumab (120), to identify gene signatures during trastuzumab treatment and uncover their potential mechanisms. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed, and a protein–protein interaction (PPI) network of the differentially expressed genes (DEGs) was constructed by Cytoscape software. There were 2284 DEGs, including 1231 up-regulated genes enriched in DNA replication, protein N-linked glycosylation via asparagine, and response to toxic substances, while 1053 down-regulated genes were enriched in axon guidance, protein localization to plasma membrane, protein stabilization, and protein glycosylation. Eight hub genes were identified from the PPI network, including GSK3B, RAC1, PXN, ERBB2, HSP90AA1, FGF2, PIK3R1 and RAC2. Our experimental results showed that GSK3B was also highly expressed in breast cancer tissues and was associated with poor survival, as was β-catenin. In conclusion, the present study indicated that the identified DEGs and hub genes further our understanding of the molecular mechanisms underlying trastuzumab treatment in BC and highlighted GSK3B, which might be used as a molecular target for the treatment of BC.

Changes in Expression of Genes Representing Key Biologic Processes after Neoadjuvant Chemotherapy in Breast Cancer, and Prognostic Implications in Residual Disease

PURPOSE

The primary aim was to derive evidence for or against the clinical importance of several biologic processes in patients treated with neoadjuvant chemotherapy (NAC) by assessing expression of selected genes with prior implications in prognosis or treatment resistance. The secondary aim was to determine the prognostic impact in residual disease of the genes' expression.

EXPERIMENTAL DESIGN

Expression levels of 24 genes were quantified by NanoString nCounter on formalin-fixed paraffin-embedded residual tumors from 126 patients treated with NAC and 56 paired presurgical biopsies. The paired t test was used for testing changes in gene expression, and Cox regression and penalized elastic-net Cox Regression for estimating HRs.

RESULTS

After NAC, 12 genes were significantly up- and 8 downregulated. Fourteen genes were significantly associated with time to recurrence in univariable analysis in residual disease. In a multivariable model, ACACB, CD3D, MKI67, and TOP2A added prognostic value independent of clinical ER(-), PgR(-), and HER2(-) status. In ER(+)/HER2(-) patients, ACACB, PAWR, and ERBB2 predicted outcome, whereas CD3D and PAWR were prognostic in ER(-)/HER2(-) patients. By use of elastic-net analysis, a 6-gene signature (ACACB, CD3D, DECORIN, ESR1, MKI67, PLAU) was identified adding prognostic value independent of ER, PgR, and HER2.

CONCLUSIONS

Most of the tested genes were significantly enriched or depleted in response to NAC. Expression levels of genes representing proliferation, stromal activation, metabolism, apoptosis, stemcellness, immunologic response, and Ras-ERK activation predicted outcome in residual disease. The multivariable gene models identified could, if validated, be used to identify patients needing additional post-neoadjuvant treatment to improve prognosis. Clin Cancer Res; 22(10); 2405-16. ©2016 AACR.

Leveraging ectopic Hsp90 expression to assay the presence of tumor cells and aggressive tumor phenotypes in breast specimens

Hsp90 has been studied extensively as a therapeutic target in breast cancer in pre-clinical and clinical trials, demonstrating a variety of roles in metastatic progression. The evidence to date suggests a compelling opportunity to leverage attributes of Hsp90 expression beyond therapeutics with potential applications in breast cancer diagnosis, prognosis, and recurrence risk assessment. In this study, we developed a completely non-destructive strategy using HS-27, a fluorescently-tethered Hsp90 inhibitor, to assay Hsp90 expression on intact tissue specimens with comparable contrast to in vivo administration routes, and demonstrate the feasibility of our approach in breast cancer patients. In addition to Hsp90 inhibition being most effective in glycolytic tumors, we found ectopic Hsp90 expression to be highest in glycolytic tumors reinforcing its role as an indicator of aggressive disease. This work sets the stage for immediately using Hsp90 to improve outcomes for breast cancer patients without affecting traditional care pathways.

LDHB and FABP4 are Associated With Progression and Poor Prognosis of Pancreatic Ductal Adenocarcinomas

Pancreatic ductal adenocarcinoma (PDAC) is a fast-growth tumor with poor prognosis. The molecular events involving in the abnormal energy metabolism have been reported without being fully identified. This study investigated the expression of FABP4 and LDHB, 2 metabolism-associated molecules, in malignant and benign lesions of pancreas by immunohistochemical staining, and analyzed their clinical and pathologic significances. The results showed that FABP4 and LDHB protein were overexpressed in PDAC tumors compared with peritumoral tissues, benign pancreatic tissues, and normal pancreatic tissues (P<0.01). The percentage of patients with FABP4 and LDHB protein overexpression was significantly higher in PDAC patients with lymph node metastasis, invasion, and tumour, node, metastasis stage III/IV disease than in patients without lymph node metastasis and invasion, and having tumour, node, metastasis stage I/II stage disease (P<0.05 or P<0.01). Benign pancreatic lesions with positive FABP4 and LDHB protein expression exhibited dysplasia or intraepithelial neoplasia I and III grade. Kaplan-Meier survival analysis showed that positive FABP4 and LDHB protein expression were associated with worse survival in PDAC patients (P<0.05 or P<0.001). Cox multivariate analysis revealed that positive FABP4 and LDHB protein expression were independent poor prognosis factors in PDAC patients. In conclusion, positive FABP4 and LDHB protein expression are associated with the progression and poor prognosis in patients with PDAC.

Cytoplasmic GPER translocation in cancer-associated fibroblasts mediates cAMP/PKA/CREB/glycolytic axis to confer tumor cells with multidrug resistance

Multiple drug resistance is a challenging issue in the clinic. There is growing evidence that the G-protein-coupled estrogen receptor (GPER) is a novel mediator in the development of multidrug resistance in both estrogen receptor (ER)-positive and -negative breast cancers, and that cancer-associated fibroblasts (CAFs) in the tumor microenvironment may be a new agent that promotes drug resistance in tumor cells. However, the role of cytoplasmic GPER of CAFs on tumor therapy remains unclear. Here we first show that the breast tumor cell-activated PI3K/AKT (phosphoinositide 3-kinase/AKT) signaling pathway induces the cytoplasmic GPER translocation of CAFs in a CRM1-dependent pattern, and leads to the activation of a novel estrogen/GPER/cAMP/PKA/CREB signaling axis that triggers the aerobic glycolysis switch in CAFs. The glycolytic CAFs feed the extra pyruvate and lactate to tumor cells for augmentation of mitochondrial activity, and this energy metabolically coupled in a 'host-parasite relationship' between catabolic CAFs and anabolic cancer cells confers the tumor cells with multiple drug resistance to several conventional clinical treatments including endocrine therapy (tamoxifen), Her-2-targeted therapy (herceptin) and chemotherapy (epirubicin). Moreover, the clinical data from 18F-fluorodeoxyglucose positron emission tomography/computed tomography further present a strong association between the GPER/cAMP/PKA/CREB pathway of stromal fibroblasts with tumor metabolic activity and clinical treatment, suggesting that targeting cytoplasmic GPER in CAFs may rescue the drug sensitivity in patients with breast cancer. Thus, our data define novel insights into the stromal GPER-mediated multiple drug resistance from the point of reprogramming of tumor energy metabolism and provide the rationale for CAFs as a promising target for clinical therapy.

A murine preclinical syngeneic transplantation model for breast cancer precision medicine

We previously demonstrated that altered activity of lysophosphatidic acid in murine mammary glands promotes tumorigenesis. We have now established and characterized a heterogeneous collection of mouse-derived syngeneic transplants (MDSTs) as preclinical platforms for the assessment of personalized pharmacological therapies. Detailed molecular and phenotypic analyses revealed that MDSTs are the most heterogeneous group of genetically engineered mouse models (GEMMs) of breast cancer yet observed. Response of MDSTs to trametinib, a mitogen-activated protein kinase (MAPK) kinase inhibitor, correlated with RAS/MAPK signaling activity, as expected from studies in xenografts and clinical trials providing validation of the utility of the model. Sensitivity of MDSTs to talazoparib, a poly(adenosine 5'-diphosphate-ribose) polymerase (PARP) inhibitor, was predicted by PARP1 protein levels and by a new PARP sensitivity predictor (PSP) score developed from integrated analysis of drug sensitivity data of human cell lines. PSP score-based classification of The Cancer Genome Atlas breast cancer suggested that a subset of patients with limited therapeutic options would be expected to benefit from PARP-targeted drugs. These results indicate that MDSTs are useful models for studies of targeted therapies, and propose novel potential biomarkers for identification of breast cancer patients likely to benefit from personalized pharmacological treatments.

A platform for high-throughput bioenergy production phenotype characterization in single cells

Driven by an increasing number of studies demonstrating its relevance to a broad variety of disease states, the bioenergy production phenotype has been widely characterized at the bulk sample level. Its cell-to-cell variability, a key player associated with cancer cell survival and recurrence, however, remains poorly understood due to ensemble averaging of the current approaches. We present a technology platform for performing oxygen consumption and extracellular acidification measurements of several hundreds to 1,000 individual cells per assay, while offering simultaneous analysis of cellular communication effects on the energy production phenotype. The platform comprises two major components: a tandem optical sensor for combined oxygen and pH detection, and a microwell device for isolation and analysis of single and few cells in hermetically sealed sub-nanoliter chambers. Our approach revealed subpopulations of cells with aberrant energy production profiles and enables determination of cellular response variability to electron transfer chain inhibitors and ion uncouplers.

Recent Progress in Triple Negative Breast Cancer Research

Triple-negative breast cancer (TNBC) is defined as a type of breast carcinoma that is negative for expression of oestrogene and progesterone hormone receptors (ER, PR) and HER2. This form of breast cancer is marked by its aggressiveness, low survival rate and lack of specific therapies. Recently, important molecular characteristics of TNBC have been highlighted and led to the identification of some biomarkers that could be used in diagnosis, as therapeutic targets or to assess the prognosis. In this review, we summarize recent progress in TNBC research focusing on the genetic and epigenetic alterations of TNBC and the potential use of these biomarkers in the targeted therapy for better management of TNBC.

LDHB may be a significant predictor of poor prognosis in osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor in children and young adults. Lactate dehydrogenase (LDH) is considered as the key glycolytic enzyme and involved in tumor initiation and metabolism. Here, we firstly found that LDHB was highly expressed in osteosarcoma cell lines. Expression profiling indicated that LDHB mRNA was elevated in osteosarcoma tissues with metastasis versus without metastasis, and LDHB high expression predicted a poor prognosis in patients. After LDHB knockdown by siRNA transfection, cell growth and proliferation were inhibited and presented a dose-dependent cell death via MTT assay. Meanwhile, wound healing and matrigel invasion assay revealed that LDHB knockdown inhibited migration and invasion activities in osteosarcoma cells. We further constructed tissue microarray in 40 osteosarcoma tissues. Correlation between LDHB and clinicopathological features indicated that LDHB expressions were associated with tumor TNM stage, recurrence and survival. Kaplan-Meier survival curve revealed that overall survival was significantly decreased in patients with high expression of LDHB. Patients with recurrence or advanced stage showed an increased LDHB, suggesting that increased LDHB was closely associated with a poor prognosis in osteosarcoma patients. Thus, LDHB can be considered as a prognostic marker for tumor recurrence and poor overall survival in osteosarcoma.

Lactate Dehydrogenase B Controls Lysosome Activity and Autophagy in Cancer

Metabolic adaptability is essential for tumor progression and includes cooperation between cancer cells with different metabolic phenotypes. Optimal glucose supply to glycolytic cancer cells occurs when oxidative cancer cells use lactate preferentially to glucose. However, using lactate instead of glucose mimics glucose deprivation, and glucose starvation induces autophagy. We report that lactate sustains autophagy in cancer. In cancer cells preferentially to normal cells, lactate dehydrogenase B (LDHB), catalyzing the conversion of lactate and NAD(+) to pyruvate, NADH and H(+), controls lysosomal acidification, vesicle maturation, and intracellular proteolysis. LDHB activity is necessary for basal autophagy and cancer cell proliferation not only in oxidative cancer cells but also in glycolytic cancer cells.

A meta-analysis of biomarkers for the prognosis of triple-negative breast cancer patients

Identification of biomarkers that has the ability to predict triple-negative breast cancer (TNBC) prognosis especially in patients undergoing chemotherapy is very important. Methods: The cohort studies that reported association between chemotherapy biomarker expression and survival outcome in TNBC patients were included in our analysis. Results: The promising markers that emerged for the prediction of disease-free survival and overall survival included Ki67, BRCA1 methylation and LC3B. Furthermore, Ki67 appeared to be also significantly associated with worse disease-free survival in TNBC patients who received anthracycline-based chemotherapy. Conclusion: This meta-analysis demonstrated that in TNBC patients receiving chemotherapy, Ki67 is a predictor for poor prognosis, BRCA1 methylation and LC3B are also potential prognostic markers. In addition, the TNBC patients with high Ki67 expression seems to display resistance to anthracycline-based chemotherapy.

Pretreatment serum lactate dehydrogenase is an independent prognostic factor for patients receiving neoadjuvant chemotherapy for locally advanced cervical cancer

For locally advanced cervical cancer (LACC), hypoxia is a characteristic property. This study aimed to investigate whether baseline lactic dehydrogenase (LDH) level, which is a marker of hypoxia, had clinical value in determining neoadjuvant chemotherapy (NACT) response and prognosis for LACC patients. The study cohort included 418 patients with a median follow‐up of 37.5 months. Cox proportional hazards models were used to assess the prognostic value of baseline LDH levels. Multivariate logistic regression analysis was performed to identify independent predictors of complete response after NACT. Backward stepwise selection with the Akaike information criterion was used to identify factors that could be entered into the multivariate regression model. Compared with patients with LDH levels <252.0 μ/L, patients with LDH levels ≥252.0 μ/L were more likely to have an elevated level of squamous cell carcinoma antigen, lymphatic vascular space involvement, lymph node metastasis, and positive parametrium and achieved lower complete remission rates. Baseline LDH levels ≥252.0 μ/L was an independent prognosticator for recurrence‐free survival (adjusted hazard ratio [HR], 3.56; 95% confidence interval [CI] 2.22–5.69; P < 0.0001) and cancer‐specific survival (adjusted HR, 3.08; 95% CI, 1.89–5.01; P < 0.0001). The predictive value of baseline LDH value remained significant in the subgroup analysis. LDH level ≥252.0 μ/L was identified as an independent predictor of complete remission after NACT (adjusted odds ratio [OR], 0.29; 95% CI, 0.15–0.58; P < 0.0001). Baseline LDH ≥252.0 μ/L is an independent prognostic predictor for patients receiving neoadjuvant chemotherapy for LACC. It helps distinguish patients with different prognosis and select patients who are more likely to benefit from NACT.

Characterization of the role Rab25 in energy metabolism and cancer using extracellular flux analysis and material balance

Rab25, by altering trafficking of critical cellular resources, influences cell metabolism and survival during stress conditions. Overall, perturbations in the vesicular trafficking machinery change cellular bioenergetics that can be directly measured in real time as Oxygen Consumption Rate, OCR (mitochondrial respiration) and Extracellular Acidification Rate, ECAR (glycolysis) by an extracellular flux analyzer (XF96, Seahorse Biosciences, MA). Additionally, overall turnover of glucose, lactate, as well as glutamine and glutamate can be measured biochemically using the YSI2900 Biochemistry Analyzer (YSI Incorporated, Life Sciences, OH). A combination of these two methods allows a precise and quantitative approach to interrogate the role of Rab25 as well as other Rab GTPases in central carbon energy metabolism.

Biomarker Development for Intraductal Papillary Mucinous Neoplasms Using Multiple Reaction Monitoring Mass Spectrometry

Intraductal papillary mucinous neoplasm (IPMN) is a common precursor of pancreatic cancer (PC). Much clinical attention has been directed toward IPMNs due to the increase in the prevalence of PC. The diagnosis of IPMN depends primarily on a radiological examination, but the diagnostic accuracy of this tool is not satisfactory, necessitating the development of accurate diagnostic biomarkers for IPMN to prevent PC. Recently, high-throughput targeted proteomic quantification methods have accelerated the discovery of biomarkers, rendering them powerful platforms for the evolution of IPMN diagnostic biomarkers. In this study, a robust multiple reaction monitoring (MRM) pipeline was applied to discovery and verify IPMN biomarker candidates in a large cohort of plasma samples. Through highly reproducible MRM assays and a stringent statistical analysis, 11 proteins were selected as IPMN marker candidates with high confidence in 184 plasma samples, comprising a training (n = 84) and test set (n = 100). To improve the discriminatory power, we constructed a six-protein panel by combining marker candidates. The multimarker panel had high discriminatory power in distinguishing between IPMN and controls, including other benign diseases. Consequently, the diagnostic accuracy of IPMN can be improved dramatically with this novel plasma-based panel in combination with a radiological examination.

Serum lactate dehydrogenase and survival following cancer diagnosis

BACKGROUND

There is evidence that high level of serum lactate dehydrogenase (LDH) is associated with poorer overall survival in several malignancies, but its link to cancer-specific survival is unclear.

METHODS

A total of 7895 individuals diagnosed with cancer between 1986 and 1999 were selected for this study. Multivariable Cox proportional hazards regression was used to assess overall and cancer-specific death by the z-score and clinical categories of serum LDH prospectively collected within 3 years before diagnosis. Site-specific analysis was performed for major cancers. Analysis was repeated by different lag times between LDH measurements and diagnosis.

RESULTS

At the end of follow-up, 5799 participants were deceased. Hazard ratios (HRs) and 95% confidence intervals (CIs) for overall and cancer-specific death in the multivariable model were 1.43 (1.31-1.56) and 1.46 (1.32-1.61), respectively, for high compared with low prediagnostic LDH. Site-specific analysis showed high LDH to correlate with an increased risk of death from prostate, pulmonary, colorectal, gastro-oesophageal, gynaecological and haematological cancers. Serum LDH assessed within intervals closer to diagnosis was more strongly associated with overall and cancer-specific death.

CONCLUSIONS

Our findings demonstrated an inverse association of baseline serum LDH with cancer-specific survival, corroborating its role in cancer progression.

Inhibition of the Warburg effect with a natural compound reveals a novel measurement for determining the metastatic potential of breast cancers

Metabolism is an important differentiating feature of cancer cells. Lactate dehydrogenases (LDH) A/B are metabolically important proteins and are involved in the critical step of inter-conversion of lactate to pyruvate. Panepoxydone (PP), a natural NF-kB inhibitor, significantly reduces the oxygen consumption and lactate production of MCF-7 and triple negative (MDA-MB-231, MDA-MB-468 and MDA-MB-453) breast cancer cells. We further observed that PP inhibited mitochondrial membrane potential and the ATP synthesis using flow cytometry. PP also up-regulated LDH-B and down-regulated LDH-A expression levels in all breast cancer cells to similar levels observed in HMEC cells. Over-expression of LDH-B in cancer cell lines leads to enhanced apoptosis, mitochondrial damage, and reduced cell migration. Analyzing the patient data set GDS4069 available on the GEO website, we observed 100% of non TNBC and 60% of TNBC patients had less LDH-B expression than LDH-A expression levels. Herein we report a new term called Glycolytic index, a novel method to calculate utilization of oxidative phosphorylation in breast cancer cells through measuring the ratio of the LDH-B to LDH-A. Furthermore, inhibitors of NF-kB could serve as a therapeutic agent for targeting metabolism and for the treatment of triple negative breast cancer.

Subtyping of breast cancer using reverse phase protein arrays

Reverse phase protein arrays (RPPAs) present a robust and sensitive high capacity platform for targeted proteomics that relies on highly specific antibodies to obtain a quantitative readout regarding phosphorylation state and abundance of proteins of interest. This review summarizes the current state of RPPA-based proteomic profiling of breast cancer in the context of existing preanalytical strategies and sample preparation protocols. RPPA-based subtypes identified so far are compared to those obtained by other approaches such as immunohistochemistry, genomics and transcriptomics. Special attention is given to discussing the potential of RPPA for biomarker discovery and biomarker validation.

Low Expression of LDHB Correlates With Unfavorable Survival in Hepatocellular Carcinoma: Strobe-Compliant Article

Lactate dehydrogenase B (LDHB) is widely expressed in adult somatic tissue and plays important roles in the development of human cancers. However, the association between LDHB expression and the clinicopathological characteristics of hepatocellular carcinoma (HCC) is not well understood. The study was to detect the expression of LDHB in human HCC and investigate the association between its expression and the clinicopathological characteristics of HCC. Immunohistochemistry (IHC) analysis was performed to characterize the expression of LDHB in HCC and matched noncancerous tissues. Kaplan-Meier survival and Cox regression analyses were employed to evaluate the prognosis of 75 HCC patients. The results showed that the expression of LDHB in HCC was significantly lower than that in noncancerous tissues. Moreover, the expression level of the LDHB protein in HCC was correlated with pathological grade (P = 0.037), vascular invasion (P = 0.037), lymph node metastasis (P = 0.016), and tumor-node metastasis (TNM) stage (P = 0.007). Cox regression analysis further revealed that LDHB expression is an independent prognostic factor for disease-free survival (P = 0.045) and overall survival (P = 0.019).These data are the first to indicate that LDHB expression is a valuable prognostic biomarker for HCC and that low LDHB expression suggests unfavorable survival outcomes in HCC patients.

Association of the Alu insertion polymorphism in the progesterone receptor gene with breast cancer in a Mexican population

INTRODUCTION

The progesterone receptor (PR) gene plays an important role in reproduction-related events. Data on polymorphisms in the PR gene have revealed associations with cancer, particularly for the Alu insertion polymorphism, which has been suggested to affect progesterone receptor function and contribute to tumor promotion in the mammary gland.

MATERIAL AND METHODS

We examined the role of the Alu insertion polymorphism in the PR gene by comparing the genotypes of 209 healthy Mexican women with those of 481 Mexican women with breast cancer (BC).

RESULTS

The genotype frequencies observed in the controls and BC patients were 0% and 4% for T2/T2 (Alu insertion), 16% and 21% for T1/T2, and 84% and 75% for T1/T1 (Alu deletion), respectively. The obtained odds ratio (OR) was 1.7, with a 95% confidence interval (95% CI) of 1.1-2.6, p = 0.009, for the T1/T2-T2/T2 genotypes. The association was also evident when the distributions of the T1/T2-T2/T2 genotypes in patients in the following categories were compared: obesity grade II (OR = 1.81, 95% CI: 1.03-3.18, p = 0.039) and the chemotherapy response (OR = 1.91, 95% CI: 1.27-3.067, p = 0.002).

CONCLUSIONS

The T1/T2-T2/T2 genotypes of the Alu insertion polymorphism in the PR gene are associated with BC susceptibility in the analyzed Mexican population.

The beneficial effects of a gas-permeable flask for expansion of Tumor-Infiltrating lymphocytes as reflected in their mitochondrial function and respiration capacity

Adoptive transfer of autologous ex vivo expanded tumor-infiltrating lymphocytes (TIL) is a highly successful cell therapy approach in the treatment of late-stage melanoma. Notwithstanding the success of this therapy, only very few centers worldwide can provide it. To make this therapy broadly available, one of the major obstacles to overcome is the complexity of culturing the TIL. Recently, major efforts have been deployed to resolve this issue. The use of the Gas-permeable flask (G-Rex) during the REP has been one application that has facilitated this process. Here we show that the use of this new device is able to rescue poor TIL growth and maintain clonal diversity while supporting an improved mitochondrial function.

Lactate dehydrogenase B is associated with the response to neoadjuvant chemotherapy in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) comprises a subset of head and neck squamous cell carcinoma (HNSCC) with poor therapeutic outcomes and high glycolytic dependency. Neoadjuvant chemotherapy regimens of docetaxel, cisplatin and 5-fluorouracil (TPF) are currently accepted as standard regimens for HNSCC patients with a high risk of distant metastatic spread. However, the antitumor outcomes of TPF neoadjuvant chemotherapy in HNSCC remain controversial. This study investigated the role of lactate dehydrogenase B (LDHB), a key glycolytic enzyme catalyzing the inter-conversion between pyruvate and lactate, in determining chemotherapy response and prognosis in OSCC patients. We discovered that a high protein level of LDHB in OSCC patients was associated with a poor response to TPF regimen chemotherapy as well as poor overall survival and disease-free survival. Our in-depth study revealed that high LDHB expression conferred resistance to taxol but not 5-fluorouracil or cisplatin. LDHB deletion sensitized OSCC cell lines to taxol, whereas the introduction of LDHB decreased sensitivity to taxol treatment. Taxol induced a pronounced impact on LDHB-down-regulated OSCC cells in terms of apoptosis, G2/M phase cell cycle arrest and energy metabolism. In conclusion, our study highlighted the critical role of LDHB in OSCC and proposed that LDHB could be used as a biomarker for the stratification of patients for TPF neoadjuvant chemotherapy and the determination of prognosis in OSCC patients.

Combined Label-Free Quantitative Proteomics and microRNA Expression Analysis of Breast Cancer Unravel Molecular Differences with Clinical Implications

Better knowledge of the biology of breast cancer has allowed the use of new targeted therapies, leading to improved outcome. High-throughput technologies allow deepening into the molecular architecture of breast cancer, integrating different levels of information, which is important if it helps in making clinical decisions. microRNA (miRNA) and protein expression profiles were obtained from 71 estrogen receptor-positive (ER(+)) and 25 triple-negative breast cancer (TNBC) samples. RNA and proteins obtained from formalin-fixed, paraffin-embedded tumors were analyzed by RT-qPCR and LC/MS-MS, respectively. We applied probabilistic graphical models representing complex biologic systems as networks, confirming that ER(+) and TNBC subtypes are distinct biologic entities. The integration of miRNA and protein expression data unravels molecular processes that can be related to differences in the genesis and clinical evolution of these types of breast cancer. Our results confirm that TNBC has a unique metabolic profile that may be exploited for therapeutic intervention.

Global analysis of protein folding thermodynamics for disease state characterization

Current methods for the large-scale characterization of disease states generally rely on the analysis of gene and/or protein expression levels. These existing methods fail to detect proteins with disease-related functions and unaltered expression levels. Here we describe the large-scale use of thermodynamic measurements of protein folding and stability for the characterization of disease states. Using the Stable Isotope Labeling with Amino Acids in Cell Culture and Stability of Proteins from Rates of Oxidation (SILAC-SPROX) technique, we assayed ∼800 proteins for protein folding and stability changes in three different cell culture models of breast cancer including the MCF-10A, MCF-7, and MDA-MB-231 cell lines. The thermodynamic stability profiles generated here created distinct molecular markers to differentiate the three cell lines, and a significant fraction (∼45%) of the differentially stabilized proteins did not have altered expression levels. Thus, the differential thermodynamic profiling strategy reported here created novel molecular signatures of breast cancer and provided additional insight into the molecular basis of the disease. Our results establish the utility of protein folding and stability measurements for the study of disease processes, and they suggest that such measurements may be useful for biomarker discovery in disease.

Identification of proteins responsible for adriamycin resistance in breast cancer cells using proteomics analysis

Chemoresistance is a poor prognostic factor in breast cancer and is a major obstacle to the successful treatment of patients receiving chemotherapy. However, the precise mechanism of resistance remains unclear. In this study, a pair of breast cancer cell lines, MCF-7 and its adriamycin-resistant counterpart MCF-7/ADR was used to examine resistance-dependent cellular responses and to identify potential therapeutic targets. We applied nanoflow liquid chromatography (nLC) and tandem mass tags (TmT) quantitative mass spectrometry to distinguish the differentially expressed proteins (DEPs) between the two cell lines. Bioinformatics analyses were used to identify functionally active proteins and networks. 80 DEPs were identified with either up- or down-regulation. Basing on the human protein-protein interactions (PPI), we have retrieved the associated functional interaction networks for the DEPs and analyzed the biological functions. Six different signaling pathways and most of the DEPs strongly linked to chemoresistance, invasion, metastasis development, proliferation, and apoptosis. The identified proteins in biological networks served to resistant drug and to select critical candidates for validation analyses by western blot. The glucose-6-phosphate dehydrogenase (G6PD), gamma-glutamyl cyclotransferase (GGCT), isocitrate dehydrogenase 1 (NADP+,soluble)(IDH1), isocitrate dehydrogenase 2 (NADP+,mitochondrial) (IDH2) and glutathione S-transferase pi 1(GSTP1), five of the critical components of GSH pathway, contribute to chemoresistance.

Suppressed expression of LDHB promotes pancreatic cancer progression via inducing glycolytic phenotype

Lactate dehydrogenase B (LDHB) is widely expressed in adult somatic tissue and is one of the two subunits of lactate dehydrogenase, which is the key glycolytic enzyme and catalyzes the interconversion of pyruvate and lactate. However, the roles of LDHB in glycolysis and tumor progression were obscure in different types of cancer. Here, we determined the roles of LDHB in pancreatic cancer development and progression. We found suppressed expression of LDHB in pancreatic cancer which was due to promoter hypermethylation and deceased expression of LDHB led to glycolytic transition. Functional analysis revealed that suppressed expression of LDHB promoted pancreatic cancer cells proliferation, invasion, and migration in hypoxia. Thus, LDHB might function as a suppressor of glycolysis and suppressed pancreatic cancer progression.

Isoform switch of pyruvate kinase M1 indeed occurs but not to pyruvate kinase M2 in human tumorigenesis

Muscle type of pyruvate kinase (PKM) is one of the key mediators of the Warburg effect and tumor metabolism. Due to alternative splicing, there are at least 12 known isoforms of the PKM gene, of which PKM1 and PKM2 are two major isoforms with only a 23 amino acid sequenced difference but quite different characteristics and functions. It was previously thought the isoform switch from PKM1 to PKM2 resulted in high PKM2 expression in tumors, providing a great advantage to tumor cells. However, this traditional view was challenged by two recent studies; one study claimed that this isoform switch does not occur during the Warburg effect; the other study asserted that the isoform switch is tissue-specific. Here, we re-analyzed the RNA sequencing data of 25 types of human tumors from The Cancer Genome Atlas Data Portal, and confirmed that PKM2 was the major isoform in the tumors and was highly elevated in addition to the entire PKM gene. We further demonstrated that the expression level of PKM1 significantly declined even though there was substantially increased expression of the entire PKM gene. The proportion of PKM1 in total transcript variants also significantly declined in tumors but the proportion of PKM2 did not change accordingly. Therefore, we conclude that the isoform switch of PKM1 does indeed occur, but it switches to other isoforms rather than PKM2. Considering the change in the expression levels of PKM1, PKM2 and the entire PKM gene, we propose that the upregulation of PKM2 is primarily due to elevated transcriptional levels of the entire PKM gene, instead of the isoform switch.

Kinetic characterization of lactate dehydrogenase in normal and malignant human breast tissues

Background

Aerobic glycolysis rate is higher in breast cancer tissues than adjacent normal tissues which providethe ATP, lactate and anabolic precursors required for tumourgenesis and metastasis. Lactate dehydrogenase (LDH) is a critical enzyme during aerobic glycolysis as it is typically responsible for the production of lactate and regeneration of NAD⁺, which allows for the continued functioning of glycolysis even in the absence of oxygen. LDH has been found to be highly expressed in breast tumors. Enzyme kinetic characteristics is related to environmentinvolving the enzyme, and tumor microenvironment has distinct features relative to adjacent normal tissues, thus we hypothesized that LDH should have different kinetic characteristics in breast tumors compared to normal breast tissues.

Methods

LDH was partially purifiedfrom human breast tumors and normal tissues, which were obtained directly from operating room. TheMichaelis-Menten constant (K_m), maximum velocity (V_max), activation energy (E_a) and enzyme efficiency in breast tumors and normal tissueswere determined.

Results

It was found that tumor LDH affinity in forward reaction was the same as normal LDH but V_max of cancerous LDH was higher relative to normal LDH. In reverse reaction, affinity of tumor LDH for lactate and NAD⁺ was lower than normal LDH, also enzyme efficiency for lactate and NAD⁺ was higher in normal samples. The E_a of reverse reaction was higher in cancerous tissues.

Conclusions

It was concluded that thelow LDH affinity for lactate and NAD⁺ is a valuable tool for preserving lactate by cancer cells. We also conclude that increasing of LDH affinity may be a valid molecular target to abolish lactate dependent tumor growth and kinetic characteristics of LDH could be a novel diagnostic parameter for human breast cancer.

Integrating transcriptomics and proteomics to show that tanshinone IIA suppresses cell growth by blocking glucose metabolism in gastric cancer cells

Background

Tanshinone IIA (TIIA) is a diterpene quinone extracted from the plant Danshen (Salvia miltiorrhiza) used in traditional Chinese herbal medicine. It has been reported to have anti-tumor potential against several kinds of cancer, including gastric cancer. In most solid tumors, a metabolic switch to glucose is a hallmark of cancer cells, which do this to provide nutrients for cell proliferation. However, the mechanism associated with glucose metabolism by which TIIA acts on gastric cancer cells remains to be elucidated.

Results

We found that TIIA treatment is able to significantly inhibit cell growth and the proliferation of gastric cancer in a dose-dependent manner. Using next-generation sequencing-based RNA-seq transcriptomics and quantitative proteomics-isobaric tags for relative and absolute quantification (iTRAQ), we characterized the mechanism of TIIA regulation in gastric cancer cell line AGS. In total, 16,603 unique transcripts and 102 proteins were identified. After enrichment analysis, we found that TIIA regulated genes are involved in carbohydrate metabolism, the cell cycle, apoptosis, DNA damage and cytoskeleton reorganization. Our proteomics data revealed the downregulation of intracellular ATP levels, glucose-6-phosphate isomerase and L-lactate dehydrogenase B chains by TIIA, which might work with disorders of glucose metabolism and extracellular lactate levels to suppress cell proliferation. The up-regulation of p53 and down-regulation of AKT was shown in TIIA- treated cells, which indicates the transformation of oncogenes. Severe DNA damage, cell cycle arrest at the G₂/M transition and apoptosis with cytoskeleton reorganization were detected in TIIA-treated gastric cancer cells.

Conclusions

Combining transcriptomics and proteomics results, we propose that TIIA treatment could lead cell stresses, including nutrient deficiency and DNA damage, by inhibiting the glucose metabolism of cancer cells. This study provides an insight into how the TIIA regulatory metabolism in gastric cancer cells suppresses cell growth, and may help improve the development of cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1230-0) contains supplementary material, which is available to authorized users.

The drs tumor suppressor regulates glucose metabolism via lactate dehydrogenase-B

Previously, we showed that drs contributes to suppression of malignant tumor formation in drs-knockout (KO) mice. In this study, we demonstrate the regulation of glucose metabolism by drs using comparisons of drs-KO and wild-type (WT) mouse embryonic fibroblasts (MEFs). Extracellular acidification, lactate concentration, and glucose consumption in drs-KO cells were significantly greater than those in WT cells. Metabolomic analyses also confirmed enhanced glycolysis in drs-KO cells. Among glycolysis-regulating proteins, expression of lactate dehydrogenase (LDH)-B was upregulated at the post-transcriptional level in drs-KO cells and increased LDH-B expression, LDH activity, and acidification of culture medium in drs-KO cells were suppressed by retroviral rescue of drs, indicating that LDH-B plays a critical role for glycolysis regulation mediated by drs. In WT cells transformed by activated K-ras, expression of endogenous drs mRNA was markedly suppressed and LDH-B expression was increased. In human cancer cell lines with low drs expression, LDH-B expression was increased. Database analyses also showed the correlation between downregulation of drs and upregulation of LDH-B in human colorectal cancer and lung adenocarcinoma tissues. Furthermore, an LDH inhibitor suppressed anchorage-independent growth of human cancer cells and MEF cells transformed by activated K-ras. These results indicate that drs regulates glucose metabolism via LDH-B. Downregulating drs may contribute to the Warburg effect, which is closely associated with malignant progression of cancer cells.

The latest progress in research on triple negative breast cancer (TNBC): risk factors, possible therapeutic targets and prognostic markers

Triple negative breast cancer (TNBC) is one type of breast cancer (BC), which is defined as negative for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (Her2). Its origins and development seem to be elusive. And for now, drugs like tamoxifen or trastuzumab which specifically apply to ER, PR or Her2 positive BC seem unforeseeable in TNBC clinical treatment. Due to its extreme malignancy, high recurrence rate and poor prognosis, a lot of work on the research of TNBC is needed. This review aims to summarize the latest findings in TNBC in risk factors, possible therapeutic targets and possible prognostic makers.

Systematically defining single-gene determinants of response to neoadjuvant chemotherapy reveals specific biomarkers

PURPOSE

We sought to systematically define determinants of the response to neoadjuvant chemotherapy to elucidate predictive biomarkers for breast cancer.

EXPERIMENTAL DESIGN

An unbiased systematic analysis was performed in multiple independent datasets to define genes predictive of complete pathologic response (pCR) following treatment with neoadjuvant chemotherapy. These genes were interrogated across estrogen receptor (ER)-positive and ER-negative breast cancer and those in common across three different treatment regimens were analyzed for optimal predictive power. Subsequent validation was performed on independent cohorts by gene expression and IHC analyses.

RESULTS

Genes that were highly associated with the response to neoadjuvant chemotherapy in breast cancer were readily defined using a computational method ranking individual genes by their respective ROC. Such predictive genes of the response to taxane-associated therapies were strongly enriched for cell-cycle control processes in both ER-positive and ER-negative breast cancer and correlated with pCR. However, other genes that were specifically associated with residual disease were also identified under other treatment conditions. Using the intersection between treatment groups, nine genes were identified that harbored strong predictive power in multiple contexts and validation cohort. In particular, the nuclear oncogene DEK was strongly associated with pCR, whereas the cell surface protein BCAM was strongly associated with residual disease. By IHC staining, these markers exhibited potent predictive power that remained significant in multivariate analysis.

CONCLUSION

Systematic computational approaches can define key genes that will be able to predict the response to chemotherapy across multiple treatment modalities yielding a small collection of biomarkers that can be readily deployed by IHC analyses.

Triple-negative breast cancer: bridging the gap from cancer genomics to predictive biomarkers

Triple-negative breast cancer (TNBC) represents a challenge clinically due to a lack of response to hormonal and HER2-targeted agents coupled with an aggressive disease course. As the biology of this breast cancer subtype is better understood, it is clear that TNBC is a heterogeneous disease and one targeted therapy is unlikely to be active in all patients. Biomarkers predictive of response to treatment are thus of great importance in TNBC. This review outlines studies evaluating biomarkers predictive of response to neoadjuvant chemotherapy and to targeted therapies in the advanced setting. The development of validated biomarkers in conjunction with novel targeted therapies represents an opportunity to improve patient outcomes in TNBC.

The value of platinum agents as neoadjuvant chemotherapy in triple-negative breast cancers: a systematic review and meta-analysis

Platinum agents such as cisplatin and carboplatin are DNA-damaging agents with activity in breast cancer (BC), particularly in the triple negative (TN) subgroup. The utility of platinum agents, in addition to standard neoadjuvant chemotherapy (NAC), is controversial. To assess the activity of platinum agents in patients with TNBC treated with NAC, we performed a systematic review and meta-analysis of all published studies. A search of PubMed, EMBASE, the Web of Science, SCOPUS, and the Cochrane Central Register of Controlled Trials was performed to identify studies that investigated platinum-based NAC in patients with TNBC. Random effect models were adopted to estimate the summary risk ratio (RR), and the publication bias was evaluated using a funnel plot and Egger's regression asymmetry test. The primary endpoints were the pooled rate of the pathologic complete response (pCR) and the RR to obtain a pCR in patients treated versus not treated with NAC containing platinum agents. 28 studies were included (six randomized controlled trials and 22 retrospective or prospective studies) for a total of 1,598 TNBC patients. Overall, the pooled rate of pCR in patients treated with platinum-based NAC was 45 %. In randomized trials, NAC containing cisplatin or carboplatin significantly increased the rate of pCR compared with nonplatinum agents (RR = 1.45, 95 % CI 1.25-1.68; P < 0.0001). Compared with non-TN, TNBCs were associated with a threefold increase in the pCR rate when treated with platinum-based NAC (RR 3.32, 95 % CI 2.39-4.61; P < 0.0001). In conclusion, pCR rates increase significantly with the addition of cisplatin or carboplatin in TNBC compared with NAC containing no platinum drugs. TN status is a predictor of benefit from platinum-based NAC.

Cancer metabolism and mass spectrometry-based proteomics

Cancer metabolism has been extensively investigated by various tools, and the fact of diverse metabolic reprogramming in cancer cells has been gradually unveiled. In this review, we discuss some contributions in cancer metabolism by general proteomic analysis and post-translational modification analysis using mass spectrometry (MS) technique. Instead of following one or several metabolic enzymes/pathways, the current MS approach can quickly identify a large number of proteins and compare their expression levels in different samples, providing a potentially comprehensive picture of cancer metabolism. The MS analyses from pancreatic cancer cells support a hypothesis that hypoxia promotes cells in solid tumor to reprogram metabolic pathways in order to minimize the oxygen consumption. The oxidative stress in pancreatic cancer cells is lower than that in normal duct cells, and the cancer cells adaptively express less antioxidant proteins, contrary to claims that oxidative stress is higher in cancer cells. Separately, the MS analyses confirm that pyruvate kinase isoform 2 (PKM2) can be detected in both cancer and normal cells, disagreeing with report that tumor cells express exclusively PKM2. In addition, MS analyses from pancreatic cancer cells demonstrate that lactate dehydrogenase-B is significantly upregulated in pancreatic cancer cells, whereas previous reports show that lactate dehydrogenase-A is overexpressed and is responsible for lactate production in cancer cells. Lastly, the result from MS analysis suggests that the glutaminolysis in pancreatic cancer cells is different from that observed in glioblastoma cells.

Quinoline 3-sulfonamides inhibit lactate dehydrogenase A and reverse aerobic glycolysis in cancer cells

Background

Most normal cells in the presence of oxygen utilize glucose for mitochondrial oxidative phosphorylation. In contrast, many cancer cells rapidly convert glucose to lactate in the cytosol, a process termed aerobic glycolysis. This glycolytic phenotype is enabled by lactate dehydrogenase (LDH), which catalyzes the inter-conversion of pyruvate and lactate. The purpose of this study was to identify and characterize potent and selective inhibitors of LDHA.

Methods

High throughput screening and lead optimization were used to generate inhibitors of LDHA enzymatic activity. Effects of these inhibitors on metabolism were evaluated using cell-based lactate production, oxygen consumption, and ¹³C NMR spectroscopy assays. Changes in comprehensive metabolic profile, cell proliferation, and apoptosis were assessed upon compound treatment.

Results

3-((3-carbamoyl-7-(3,5-dimethylisoxazol-4-yl)-6-methoxyquinolin-4-yl) amino) benzoic acid was identified as an NADH-competitive LDHA inhibitor. Lead optimization yielded molecules with LDHA inhibitory potencies as low as 2 nM and 10 to 80-fold selectivity over LDHB. Molecules in this family rapidly and profoundly inhibited lactate production rates in multiple cancer cell lines including hepatocellular and breast carcinomas. Consistent with selective inhibition of LDHA, the most sensitive breast cancer cell lines to lactate inhibition in hypoxic conditions were cells with low expression of LDHB. Our inhibitors increased rates of oxygen consumption in hepatocellular carcinoma cells at doses up to 3 microM, while higher concentrations directly inhibited mitochondrial function. Analysis of more than 500 metabolites upon LDHA inhibition in Snu398 cells revealed that intracellular concentrations of glycolysis and citric acid cycle intermediates were increased, consistent with enhanced Krebs cycle activity and blockage of cytosolic glycolysis. Treatment with these compounds also potentiated PKM2 activity and promoted apoptosis in Snu398 cells.

Conclusions

Rapid chemical inhibition of LDHA by these quinoline 3-sulfonamids led to profound metabolic alterations and impaired cell survival in carcinoma cells making it a compelling strategy for treating solid tumors that rely on aerobic glycolysis for survival.