Lactate dehydrogenase 5 expression in operable colorectal cancer: strong association with survival and activated vascular endothelial growth factor pathway--a report of the Tumour Angiogenesis Research Group

Metabolism score and machine learning models for the prediction of esophageal squamous cell carcinoma progression

The incomplete prediction of prognosis in esophageal squamous cell carcinoma (ESCC) patients is attributed to various therapeutic interventions and complex prognostic factors. Consequently, there is a pressing demand for enhanced predictive biomarkers that can facilitate clinical management and treatment decisions. This study recruited 491 ESCC patients who underwent surgical treatment at Huashan Hospital, Fudan University. We incorporated 14 blood metabolic indicators and identified independent prognostic indicators for overall survival through univariate and multivariate analyses. Subsequently, a metabolism score formula was established based on the biochemical markers. We constructed a nomogram and machine learning models utilizing the metabolism score and clinically significant prognostic features, followed by an evaluation of their predictive accuracy and performance. We identified alkaline phosphatase, free fatty acids, homocysteine, lactate dehydrogenase, and triglycerides as independent prognostic indicators for ESCC. Subsequently, based on these five indicators, we established a metabolism score that serves as an independent prognostic factor in ESCC patients. By utilizing this metabolism score in conjunction with clinical features, a nomogram can precisely predict the prognosis of ESCC patients, achieving an area under the curve (AUC) of 0.89. The random forest (RF) model showed superior predictive ability (AUC = 0.90, accuracy = 86%, Matthews correlation coefficient = 0.55). Finally, we used an RF model with optimal performance to establish an online predictive tool. The metabolism score developed in this study serves as an independent prognostic indicator for ESCC patients.

Development of human lactate dehydrogenase a inhibitors: high-throughput screening, molecular dynamics simulation and enzyme activity assay

Lactate dehydrogenase A (LDHA) is highly expressed in many tumor cells and promotes the conversion of pyruvate to lactic acid in the glucose pathway, providing energy and synthetic precursors for rapid proliferation of tumor cells. Therefore, inhibition of LDHA has become a widely concerned tumor treatment strategy. However, the research and development of highly efficient and low toxic LDHA small molecule inhibitors still faces challenges. To discover potential inhibitors against LDHA, virtual screening based on molecular docking techniques was performed from Specs database of more than 260,000 compounds and Chemdiv-smart database of more than 1,000 compounds. Through molecular dynamics (MD) simulation studies, we identified 12 potential LDHA inhibitors, all of which can stably bind to human LDHA protein and form multiple interactions with its active central residues. In order to verify the inhibitory activities of these compounds, we established an enzyme activity assay system and measured their inhibitory effects on recombinant human LDHA. The results showed that Compound 6 could inhibit the catalytic effect of LDHA on pyruvate in a dose-dependent manner with an EC50 value of 14.54 ± 0.83 µM. Further in vitro experiments showed that Compound 6 could significantly inhibit the proliferation of various tumor cell lines such as pancreatic cancer cells and lung cancer cells, reduce intracellular lactic acid content and increase intracellular reactive oxygen species (ROS) level. In summary, through virtual screening and in vitro validation, we found that Compound 6 is a small molecule inhibitor for LDHA, providing a good lead compound for the research and development of LDHA related targeted anti-tumor drugs.

Deletion of endothelial IGFBP5 protects against ischaemic hindlimb injury by promoting angiogenesis

BACKGROUND

Angiogenesis is critical for forming new blood vessels from antedating vascular vessels. The endothelium is essential for angiogenesis, vascular remodelling and minimisation of functional deficits following ischaemia. The insulin-like growth factor (IGF) family is crucial for angiogenesis. Insulin-like growth factor-binding protein 5 (IGFBP5), a binding protein of the IGF family, may have places in angiogenesis, but the mechanisms are not yet completely understood. We sought to probe whether IGFBP5 is involved in pathological angiogenesis and uncover the molecular mechanisms behind it.

METHODS AND RESULTS

IGFBP5 expression was elevated in the vascular endothelium of gastrocnemius muscle from critical limb ischaemia patients and hindlimb ischaemic (HLI) mice and hypoxic human umbilical vein endothelial cells (HUVECs). In vivo, loss of endothelial IGFBP5 (IGFBP5EKO) facilitated the recovery of blood vessel function and limb necrosis in HLI mice. Moreover, skin damage healing and aortic ring sprouting were faster in IGFBP5EKO mice than in control mice. In vitro, the genetic inhibition of IGFBP5 in HUVECs significantly promoted tube formation, cell proliferation and migration by mediating the phosphorylation of IGF1R, Erk1/2 and Akt. Intriguingly, pharmacological treatment of HUVECs with recombinant human IGFBP5 ensued a contrasting effect on angiogenesis by inhibiting the IGF1 or IGF2 function. Genetic inhibition of IGFBP5 promoted cellular oxygen consumption and extracellular acidification rates via IGF1R-mediated glycolytic adenosine triphosphate (ATP) metabolism. Mechanistically, IGFBP5 exerted its role via E3 ubiquitin ligase Von Hippel-Lindau (VHL)-regulated HIF1α stability. Furthermore, the knockdown of the endothelial IGF1R partially abolished the reformative effect of IGFBP5EKO mice post-HLI.

CONCLUSION

Our findings demonstrate that IGFBP5 ablation enhances angiogenesis by promoting ATP metabolism and stabilising HIF1α, implying IGFBP5 is a novel therapeutic target for treating abnormal angiogenesis-related conditions.

Mitochondrial Proteins as Metabolic Biomarkers and Sites for Therapeutic Intervention in Primary and Metastatic Cancers

Accelerated aerobic glycolysis is one of the main metabolic alterations in cancer, associated with malignancy and tumor growth. Although glycolysis is one of the most studied properties of tumor cells, recent studies demonstrate that oxidative phosphorylation (OxPhos) is the main ATP provider for the growth and development of cancer. In this last regard, the levels of mRNA and protein of OxPhos enzymes and transporters (including glutaminolysis, acetate and ketone bodies catabolism, free fatty acid β-oxidation, Krebs Cycle, respiratory chain, phosphorylating system- ATP synthase, ATP/ADP translocator, Pi carrier) are altered in tumors and cancer cells in comparison to healthy tissues and organs, and non-cancer cells. Both energy metabolism pathways are tightly regulated by transcriptional factors, oncogenes, and tumor-suppressor genes, all of which dictate their protein levels depending on the micro-environmental conditions and the type of cancer cell, favoring cancer cell adaptation and growth. In the present review paper, variation in the mRNA and protein levels as well as in the enzyme/ transporter activities of the OxPhos machinery is analyzed. An integral omics approach to mitochondrial energy metabolism pathways may allow for identifying their use as suitable, reliable biomarkers for early detection of cancer development and metastasis, and for envisioned novel, alternative therapies.

Synergistic action of lactoferrin in enhancing the safety and effectiveness of docetaxel treatment against prostate cancer

BACKGROUND

Tumor metastasis is promoted by an immunosuppressive environment. Lactoferrin (Lf) is known to regulate immunological activity in tumor cells and inhibit processes associated with tumor metastasis. A delivery of lactoferrin with docetaxel (DTX) in prostate cancer cells in the form of DTX-loaded lactoferrin nanoparticles (DTX-LfNPs) would provide a dual activity wherein the lactoferrin affects metastasis and DTX chemotherapeutically inhibits mitosis and cell division.

METHODS

DTX-LfNPs were prepared using sol-oil chemistry, and particles were characterized using transmission electron microscopy. Antiproliferation activity was analyzed in prostate cancer Mat Ly Lu cells. The target localization and efficacy of DTX-LfNPs were studied in an orthotopic prostate cancer induced by Mat Ly Lu cells in a rat model. Biomarkers were estimated using ELISA and biochemical reactions.

RESULTS

DTX was loaded in pure Lf nanoparticles without involving any chemical modification and conjugation, thus when these nanoparticles are delivered in cancer cells both DTX and Lf will be present in biologically active forms. DTX-LfNps exhibit a spherical morphology of dimension of 60 ± 10 nm with DTX Encapsulation Efficiency of 62.06 ± 4.07%. Competition experiments using soluble Lf confirm that DTX-LfNPs enter prostate cancer cells through the Lf receptor. DTX-LfNPs exhibit an improved anti-proliferative activity by 2.5 times compared to DTX. Further, analysis of the bioavailability of the drug in the prostate showed that DTX-LfNPs increased drug bioavailability in the prostate by two times more than the DTX. The analysis of efficacy in the Mat Ly Lu cells-induced orthotopic prostate cancer model showed that DTX-LfNPs significantly enhanced the anti-cancer activity compared to DTX in terms of regression of weight and volume of prostate tissue, the efficacy was confirmed by histochemical analysis. Lf provides synergistic activity along with DTX in inhibiting metastasis as assessed by the reduction of lactate dehydrogenase, alkaline phosphatase, TNF alpha, and IFNγ. LfNPs facilitate higher DTX localization along with Lf-mediated protection from DTX-associated toxicity to neutrophils and kidneys as assessed by C-reactive protein, creatinine, and uric acid. Thus, DTX LfNPs show a dual action by enhancing DTX bioavailability in prostate along with Lf-mediated suppression of metastasis as well as DTX-associated toxicity.

CONCLUSION

In conclusion, DTX-LfNPs enhance the bioavailability of DTX in the prostate along with Lf-assisted improvement in inhibition of tumor metastasis and drug-associated toxicity.

Metabolic enzyme LDHA activates Rac1 GTPase as a noncanonical mechanism to promote cancer

The glycolytic enzyme lactate dehydrogenase A (LDHA) is frequently overexpressed in cancer, which promotes glycolysis and cancer. The oncogenic effect of LDHA has been attributed to its glycolytic enzyme activity. Here we report an unexpected noncanonical oncogenic mechanism of LDHA; LDHA activates small GTPase Rac1 to promote cancer independently of its glycolytic enzyme activity. Mechanistically, LDHA interacts with the active form of Rac1, Rac1-GTP, to inhibit Rac1-GTP interaction with its negative regulator, GTPase-activating proteins, leading to Rac1 activation in cancer cells and mouse tissues. In clinical breast cancer specimens, LDHA overexpression is associated with higher Rac1 activity. Rac1 inhibition suppresses the oncogenic effect of LDHA. Combination inhibition of LDHA enzyme activity and Rac1 activity by small-molecule inhibitors displays a synergistic inhibitory effect on breast cancers with LDHA overexpression. These results reveal a critical oncogenic mechanism of LDHA and suggest a promising therapeutic strategy for breast cancers with LDHA overexpression.

Biology and therapeutic applications of the proton-coupled folate transporter

INTRODUCTION

The proton-coupled folate transporter (PCFT; SLC46A1) was discovered in 2006 as the principal mechanism by which folates are absorbed in the intestine and the causal basis for hereditary folate malabsorption (HFM). In 2011, it was found that PCFT is highly expressed in many tumors. This stimulated interest in using PCFT for cytotoxic drug targeting, taking advantage of the substantial levels of PCFT transport and acidic pH conditions commonly associated with tumors.

AREAS COVERED

We summarize the literature from 2006 to 2022 that explores the role of PCFT in the intestinal absorption of dietary folates and its role in HFM and as a transporter of folates and antifolates such as pemetrexed (Alimta) in relation to cancer. We provide the rationale for the discovery of a new generation of targeted pyrrolo[2,3-d]pyrimidine antifolates with selective PCFT transport and inhibitory activity toward de novo purine biosynthesis in solid tumors. We summarize the benefits of this approach to cancer therapy and exciting new developments in the structural biology of PCFT and its potential to foster refinement of active structures of PCFT-targeted anti-cancer drugs.

EXPERT OPINION

We summarize the promising future and potential challenges of implementing PCFT-targeted therapeutics for HFM and a variety of cancers.

Acetylation of Lactate Dehydrogenase Negatively Regulates the Acidogenicity of Streptococcus mutans

Lysine acetylation, a ubiquitous and dynamic regulatory posttranslational modification (PTM), affects hundreds of proteins across all domains of life. In bacteria, lysine acetylation can be found in many essential pathways, and it is also crucial for bacterial virulence. However, the biological significance of lysine acetylation events to bacterial virulence factors remains poorly characterized. In Streptococcus mutans, the acetylome profiles help identify several lysine acetylation sites of lactate dehydrogenase (LDH), which catalyzes the conversion of pyruvate to lactic acid, causing the deterioration of teeth. We investigated the regulatory mechanism of LDH acetylation and characterized the effect of LDH acetylation on its function. We overexpressed the 15 Gcn5 N-acetyltransferases (GNAT) family members in S. mutans and showed that the acetyltransferase ActA impaired its acidogenicity by acetylating LDH. Additionally, enzymatic acetyltransferase reactions demonstrated that purified ActA could acetylate LDH in vitro, and 10 potential lysine acetylation sites of LDH were identified by mass spectrometry, 70% of which were also detected in vivo. We further demonstrated that the lysine acetylation of LDH inhibited its enzymatic activity, and a subsequent rat caries model showed that ActA impaired the cariogenicity of S. mutans. Collectively, we demonstrated that ActA, the first identified and characterized acetyltransferase in S. mutans, acetylated the LDH enzymatically and inhibited its enzymatic activity, thereby providing a starting point for the further analysis of the biological significance of lysine acetylation in the virulence of S. mutans.

Serum Extracellular Vesicle Stratifin Is a Biomarker of Perineural Invasion in Patients With Colorectal Cancer and Predicts Worse Prognosis

Previous studies have shown that the presence of perineural invasion (PNI) is associated with a significantly worse prognosis in colorectal cancer (CRC) patients. In this study, we performed a detailed analysis of the diversity of extracellular vesicles (EV) between NPNI (non-PNI) and PNI using quantitative proteomics and aim to investigate the mechanisms underlying PNI in colorectal cancer. Quantitative proteomics technology was used to identify the proteome of serum-purified EVs from CRC patients with and without PNI (PNI and non-PNI (NPNI) groups, respectively) and healthy volunteers. Mass spectrometry data were verified by ELISA and Western blot analyses. The proteomic profile of serum EVs from the PNI group differed from that of those in the NPNI group. Serum-derived EVs from the PNI promoted more significant cellular mobility than EVs derived from the NPNI group. EV stratifin (SFN) expression levels demonstrated an area under the receiver operating characteristic curve values of 0.84 for discriminating patients with PNI from NPNI patients. Moreover, EV SFN expression levels were an independent predictor of CRC prognosis. In this study, we identified SFN as a potential biomarker for the diagnosis of PNI in stage II CRC patients.

Prognostic Value of Lactate Dehydrogenase in Second-Line Immunotherapy for Advanced Esophageal Squamous Cell Carcinoma

Background: Immunotherapy is recommended by the NCCN (National Comprehensive Cancer Network) guidelines as the standard second-line treatment for advanced esophageal squamous cell carcinoma (ESCC). Patients with advanced ESCC can benefit from immunotherapy, but the overall survival time (OS) is still not satisfactory. Therefore, it is of great importance to select effective prognostic indicators. Methods: A retrospective follow-up study was conducted from January 2018 to January 2020 among 44 patients with advanced ESCC treated with second-line immune checkpoint inhibitors (programmed death -1 blocking agents) in our hospital. The cutoff values of baseline lactate dehydrogenase (LDH), LDH level at week 8, serum albumin, hemoglobin, neutrophils, monocytes, and platelets were obtained by receiver operating characteristic (ROC) curves. The Kaplan-Meier method was used to analyze the relationship between LDH at baseline, LDH level at week 8, and LDH changes during treatment with progression-free survival (PFS) and OS time. The Cox proportional hazards model was used for univariate and multivariate analyses to determine the predictors of OS. Results: In univariate analysis, we found patients with lower baseline LDH levels (cutoff value: 200 U/L) had a better median PFS (8 months vs. 3 months; HR = 2.420, 95% CI: 1.178-4.971, p = 0.016) and OS (14 months vs. 6 months; HR = 3.637, 95% CI: 1.638-8.074, p = 0.004). The level of LDH at week 8 and the changes in LDH during treatment were not significantly associated with PFS or OS. The multivariate analyses showed that baseline LDH was an independent predictor of PFS (HR = 2.712, 95% CI: 1.147-6.409, p = 0.023) and OS (HR = 6.260, 95% CI: 2.320-16.888, p < 0.001), and the monocyte count (HR = 0.389, 95% CI: 0.162-0.934, p = 0.035) was significantly associated with OS. Conclusion: Serum LDH is a powerful independent factor for PFS and OS in advanced ESCC patients treated with anti-PD-1 therapy.

LDH-A—Modulation and the Variability of LDH Isoenzyme Profiles in Murine Gliomas: A Link with Metabolic and Growth Responses

Three murine glioma cell lines (GL261, CT2A, and ALTS1C1) were modified to downregulate the expression of the murine LDH-A gene using shRNA, and compared to shRNA scrambled control (NC) cell lines. Differences in the expression of LDH-A and LDH-B mRNA, protein and enzymatic activity, as well as their LDH isoenzyme profiles, were observed in the six cell lines, and confirmed successful LDH-A KD. LDH-A KD (knock-down) resulted in metabolic changes in cells with a reduction in glycolysis (GlycoPER) and an increase in basal respiratory rate (mitoOCR). GL261 cells had a more limited ATP production capacity compared to CT2A and ALTS1C1 cells. An analysis of mRNA expression data indicated that: (i) GL261 LDH-A KD cells may have an improved ability to metabolize lactate into the TCA cycle; and (ii) that GL261 LDH-A KD cells can upregulate lipid metabolism/fatty acid oxidation pathways, whereas the other glioma cell lines do not have this capacity. These two observations suggest that GL261 LDH-A KD cells can develop/activate alternative metabolic pathways for enhanced survival in a nutrient-limited environment, and that specific nutrient limitations have a variable impact on tumor cell metabolism and proliferation. The phenotypic effects of LDH-A KD were compared to those in control (NC) cells and tumors. LDH-A KD prolonged the doubling time of GL261 cells in culture and prevented the formation of subcutaneous flank tumors in immune-competent C57BL/6 mice, whereas GL261 NC tumors had a prolonged growth delay in C57BL/6 mice. In nude mice, both LDH-A KD and NC GL261 tumors grew rapidly (more rapidly than GL261 NC tumors in C57BL/6 mice), demonstrating the impact of an intact immune system on GL261 tumor growth. No differences between NC and KD cell proliferation (in vitro) or tumor growth in C57BL/6 mice (doubling time) were observed for CT2A and ALTS1C1 cells and tumors, despite the small changes to their LDH isoenzyme profiles. These results suggest that GL261 glioma cells (but not CT2A and ALTS1C1 cells) are pre-programmed to have the capacity for activating different metabolic pathways with higher TCA cycle activity, and that this capacity is enhanced by LDH-A depletion. We observed that the combined impact of LDH-A depletion and the immune system had a significant impact on the growth of subcutaneous-located GL261 tumors.

Versatile activity and morphological effects of zinc oxide submicron particles as anticancer agents

Background: Submicron particles (SMPs), as novel bionanomaterials, offer complementary benefits to their conventional nano-counterparts. Aim: To explore zinc oxide (ZnO) SMPs' bioimaging and anticancer potentials. Materials & methods: ZnO SMPs were synthesized into two shapes. Fluorescent spectrum and microscopy were studied for the bioimaging property. Wound healing and Live/Dead assays of glioblastoma cells were characterized for anticancer activities. Results: ZnO SMPs exhibited a high quantum yield (49%) with stable orange fluorescence emission. Both morphologies (most significant in the rod shape) showed tumor-selective properties in cytotoxicity, inhibition to cell migration and attenuating the cancer-upregulated genes. The tumor selectivity was attributed to particle degradation and surface properties on pH dependency. Conclusion: The authors propose that ZnO SMPs could be a promising anticancer drug with tunable, morphology-dependent properties for bioimaging and controlled release.

The critical function of metabolic reprogramming in cancer metastasis

Cancer metastasis is the leading cause of cancer‐related death. It is a complex, inefficient, and multistep process related to poor prognosis and high mortality of patients. Increasing evidence has shown that metabolic programming is a recognized hallmarker of cancer, plays a critical role in cancer metastasis. Metabolism alterations of glucose, lipid, and amino acid provide cancer cells with energy and substances for biosynthesis, maintain biofunctions and significantly affect proliferation, invasion, and metastasis of cancer cells. Tumor microenvironment (TME) is a complex system formed by varieties of cellular and noncellular elements. Nontumor cells in TME also undergo metabolic reprogramming or respond to metabolites to promote migration and invasion of cancer cells. A comprehensive understanding of the regulatory mechanism in metastasis from the metabolic reprogramming aspect is required to develop new therapeutic strategies combatting cancer metastasis. This review illustrates the metabolic reprogramming and interaction of cancer cells and nontumor cells in the TME, and the development of treatment strategies targeting metabolism alterations.

Clinical Significance and Prognostic Value of Lactate Dehydrogenase Expression in Cervical Cancer

Background: Lactate dehydrogenase (LDH) is a marker of injury and disease as it is expressed extensively in numerous cell types and tissues. Moreover it is released during tissue breakdown, and is elevated in cancerous tissues. However, the clinical significance and prognostic value of LDH as a tumor marker have been subject to considerable discussion. Objective: In this study, clinical serum LDH data from patients with cervical cancer (CC), CC microarray data, and RNA-seq data were integrated to assess the expression of LDH in CC. Methods: A total of 204 patients with newly diagnosed CC and 204 age-matched healthy controls were included to evaluate serum LDH levels in CC and non-cancer samples. External microarrays and RNA-seq datasets were collected for the differential expression analysis of LDH in CC and non-cancer tissue samples. Kaplan-Meier survival curves of the prognostic value of LDH for CC were plotted for RNA-seq data. Functional enrichment analysis was performed for the genes co-expressed with LDH. Results: The data from our in-house clinical cases as well as the data extracted from microarrays and RNA-seq databases demonstrated significant overexpression of LDH in CC samples. Elevated LDH expression levels were associated with poor overall survival in CC patients. The genes co-expressed with LDH were significantly correlated with the biological processes and pathways, associated with nuclear division, the condensed chromosome, protein serine/threonine kinase activity, and the cell cycle. Conclusion: In conclusion, LDH upregulation might serve as a therapeutic and prognostic biomarker for CC.

Association of lung immune prognostic index with survival outcome in advanced thymic carcinoma patients treated with palliative intent chemotherapy

Background

Methods

Results

Conclusions

Expression of proteins associated with the Warburg-effect and survival in colorectal cancer

Previous research has suggested that the expression of proteins related to the Warburg effect may have prognostic value in colorectal cancer (CRC), but results remain inconsistent. Our objective was to investigate the relationship between Warburg-subtypes and patient survival in a large population-based series of CRC patients. In the present study, we investigated the expression of six proteins related to the Warburg effect (LDHA, GLUT1, MCT4, PKM2, p53, PTEN) by immunohistochemistry on tissue microarrays (TMAs) from 2,399 incident CRC patients from the prospective Netherlands Cohort Study. Expression levels of the six proteins were combined into a pathway-based sum-score and patients were categorised into three Warburg-subtypes (low/moderate/high). The associations between Warburg-subtypes and CRC-specific and overall survival were investigated using Kaplan-Meier curves and Cox regression models. CRC patients were classified as Warburg-low (n = 695, 29.0%), Warburg-moderate (n = 858, 35.8%) or Warburg-high (n = 841, 35.1%). Patients with Warburg-high CRC had the poorest CRC-specific [hazard ratio (HR) 1.17; 95% CI 1.00-1.38] and overall survival (HR 1.19; 95% CI 1.05-1.35), independent of known prognostic factors. In stratified analyses, this was particularly true for patients with tumour-node-metastasis (TNM) stage III CRC (HR_CRC-specific 1.45; 95% CI 1.10-1.92 and HR_overall 1.47; 95% CI 1.15-1.87), and cancers located in the rectum (HR_overall 1.56; 95% CI 1.15-2.13). To our knowledge, this is the first study to identify the prognostic value of immunohistochemistry-based Warburg-subtypes in CRC. Our data suggest that Warburg-subtypes are related to potentially important differences in CRC survival. Further research is required to validate our findings and to investigate the potential clinical utility of these Warburg-subtypes in CRC.

Pieces of the Complex Puzzle of Cancer Cell Energy Metabolism: An Overview of Energy Metabolism and Alternatives for Targeted Cancer Therapy

Over the past decades, several advances in cancer cell biology have led to relevant details about a phenomenon called the 'Warburg effect'. Currently, it has been accepted that the Warburg effect is not compatible with all cancer cells, and thus the process of aerobic glycolysis is now challenged by the knowledge of a large number of cells presenting mitochondrial function. The energy metabolism of cancer cells is focused on the bioenergetic and biosynthetic pathways in order to meet the requirements of rapid proliferation. Changes in the metabolism of carbohydrates, amino acids and lipids have already been reported for cancer cells and this might play an important role in cancer progression. To the best of our knowledge, these changes are mainly attributed to genetic reprogramming which leads to the transformation of a healthy into a cancerous cell. Indeed, several enzymes that are highly relevant for cellular energy are targets of oncogenes (e.g. PI3K, HIF1, and Myc) and tumor suppressor proteins (e.g. p53). As a consequence of extensive studies on cancer cell metabolism, some new therapeutic strategies have appeared that aim to interrupt the aberrant metabolism, in addition to influencing genetic reprogramming in cancer cells. In this review, we present an overview of cancer cell metabolism (carbohydrate, amino acid, and lipid), and also describe oncogenes and tumor suppressors that directly affect the metabolism. We also discuss some of the potential therapeutic candidates which have been designed to target and disrupt the main driving forces associated with cancer cell metabolism and proliferation.

Functional inhibition of lactate dehydrogenase suppresses pancreatic adenocarcinoma progression

BACKGROUND

Pancreatic adenocarcinoma (PAAD) a highly lethal malignancy. The current use of clinical parameters may not accurately predict the clinical outcome, which further renders the unsatisfactory therapeutic outcome.

METHODS

In this study, we retrospectively analyzed the clinical-pathological characteristics and prognosis of 253 PAAD patients. Univariate, multivariate, and Kaplan-Meier survival analyses were conducted to assess risk factors and clinical outcomes. For functional study, we performed bidirectional genetic manipulation of lactate dehydrogenase A (LDHA) in PAAD cell lines to measure PAAD progression by both in vitro and in vivo assays.

RESULTS

LDHA is particularly overexpressed in PAAD tissues and elevated serum LDHA-transcribed isoenzymes-5 (LDH-5) was associated with poorer patients' clinical outcomes. Genetic overexpression of LDHA promoted the proliferation and invasion in vitro, and tumor growth and metastasis in vivo in murine PAAD orthotopic models, while knockdown of LDHA exhibited opposite effects. LDHA-induced L-lactate production was responsible for the LDHA-facilitated PAAD progression. Mechanistically, LDHA overexpression reduced the phosphorylation of metabolic regulator AMPK and promoted the downstream mTOR phosphorylation in PAAD cells. Inhibition of mTOR repressed the LDHA-induced proliferation and invasion. A natural product berberine was selected as functional inhibitor of LDHA, which reduced activity and expression of the protein in PAAD cells. Berberine inhibited PAAD cells proliferation and invasion in vitro, and suppressed tumor progression in vivo. The restoration of LDHA attenuated the suppressive effect of berberine on PAAD.

CONCLUSIONS

Our findings suggest that LDHA may be a novel biomarker and potential therapeutic target of human PAAD.

High Pretreatment LDH Predicts Poor Prognosis in Hypopharyngeal Cancer

Background

Elevated pretreatment lactate dehydrogenase (LDH) has been associated with poor prognosis in various malignancies; however, its prognostic role in hypopharyngeal cancer remains elusive. In this study, we aimed to assess the association between pretreatment LDH and clinical outcome of hypopharyngeal cancer.

Methods

We retrospectively collected 198 hypopharyngeal cancer patients treated with surgery in our institution between 2004 and 2018. The prognostic role of pretreatment LDH was explored by using univariate and multivariate analyses. Besides, subgroup analysis was performed based on T stage.

Results

Three-year and Five-year of disease-free survival (DFS, 67.0 vs. 57.4%, 65.8 vs. 39.8%, p = 0.007) and overall survival (OS, 74.8 vs. 68.9%, 66.8 vs. 50.8%, p = 0.006) exhibited significant differences between low LDH level and high LDH level groups. Univariate analysis showed that pretreatment elevated serum LDH served as an unfavorable determinant with regard to DFS and OS. Further multivariate analysis also confirmed that LDH was an independent predictor for DFS and OS. Additionally, N status and age were also found to be significantly associated with both DFS and OS.

Conclusion

Pretreatment elevated serum LDH is an inferior prognostic factor for patients with hypopharyngeal cancer. These results should be validated by more multicenter and prospective studies.

The Expression Patterns of BECN1, LAMP2, and PINK1 Genes in Colorectal Cancer Are Potentially Regulated by Micrornas and CpG Islands: An In Silico Study

Background: Autophagy plays a dual role of tumor suppression and tumor promotion in colorectal cancer. The study aimed to find those microRNAs (miRNAs) important in BECN1, LAMP2, and PINK1 regulation and to determine the possible role of the epigenetic changes in examined colorectal cancer using an in silico approach. Methods: A total of 44 pairs of surgically removed tumors at clinical stages I‒IV and healthy samples (marginal tissues) from patients’ guts were analyzed. Analysis of the obtained results was conducted using the PL-Grid Infrastructure and Statistica 12.0 program. The miRNAs and CpG islands were estimated using the microrna.org database and MethPrimer program. Results: The autophagy-related genes were shown to be able to be regulated by miRNAs (BECN1—49 mRNA, LAMP2—62 mRNA, PINK1—6 mRNA). It was observed that promotion regions containing at least one CpG region were present in the sequence of each gene. Conclusions: The in silico analysis performed allowed us to determine the possible role of epigenetic mechanisms of regulation gene expression, which may be an interesting therapeutic target in the treatment of colorectal cancer.

Inhibition of glycolysis by targeting lactate dehydrogenase A facilitates hyaluronan synthase 2 synthesis in synovial fibroblasts of temporomandibular joint osteoarthritis

OBJECTIVE

Although associations between dysregulated glucose metabolism and human rheumatoid arthritis have been reported, the disturbance and influence of glycolytic metabolism on temporomandibular joint osteoarthritis remains unclear. This study aimed to investigate the expression level and metabolite profile of the critical glycolytic enzyme, lactate dehydrogenase A (LDHA) in synovial fibroblasts (SFs) of TMJOA, assess the effect of glycolytic inhibition on synthesis of hyaluronan synthase 2 (HAS2) and inflammation progression in these cells.

METHODS

Immunohistochemistry and western blotting were performed to detect the expression of LDHA in the lining and sub-lining layers of synovial tissue and SFs. MTT and EdU assays were used to measure the cell proliferation. The cell apoptosis were demonstrated by TUNEL staining and Annexin V/PI double staining. A potent and specific inhibitor of LDHA, GSK2837808A, was administrated to suppress the activity of LDHA and detect the potential efficacy on HAS2.

RESULTS

LDHA expression was dramatically higher in the synovial tissue and SFs from TMJOA patients compared to control groups. LDHA inhibition impaired active LDHA performance, suppressed the glucose uptake and decreased lactate concentration. Furthermore, GSK2837808A reversed the occurrence of low ratio of ATP/AMP, high level of Adenosine Monophosphate-activated Protein Kinase (AMPK) activation, disturbed HAS2 synthesis and hyaluronic acid (HA) production by inhibiting LDHA. The cellular viability and cell cycle were not affected by GSK2837808A at the working concentration.

CONCLUSIONS

Targeting LDHA using its specific suppressant GSK2837808A impeded lactate secretion and contributed to HAS2 and HA synthesis in TMJOA SFs, providing the vital role of LDHA associated with TMJOA pathogenesis and a novel therapeutic approach for TMJOA.

Impact of hypoxia on chemoresistance of mesothelioma mediated by the proton-coupled folate transporter, and preclinical activity of new anti-LDH-A compounds

BACKGROUND

Expression of proton-coupled folate transporter (PCFT) is associated with survival of mesothelioma patients treated with pemetrexed, and is reduced by hypoxia, prompting studies to elucidate their correlation.

METHODS

Modulation of glycolytic gene expression was evaluated by PCR arrays in tumour cells and primary cultures growing under hypoxia, in spheroids and after PCFT silencing. Inhibitors of lactate dehydrogenase (LDH-A) were tested in vitro and in vivo. LDH-A expression was determined in tissue microarrays of radically resected malignant pleural mesothelioma (MPM, N = 33) and diffuse peritoneal mesothelioma (DMPM, N = 56) patients.

RESULTS

Overexpression of hypoxia marker CAIX was associated with low PCFT expression and decreased MPM cell growth inhibition by pemetrexed. Through integration of PCR arrays in hypoxic cells and spheroids and following PCFT silencing, we identified the upregulation of LDH-A, which correlated with shorter survival of MPM and DMPM patients. Novel LDH-A inhibitors enhanced spheroid disintegration and displayed synergistic effects with pemetrexed in MPM and gemcitabine in DMPM cells. Studies with bioluminescent hypoxic orthotopic and subcutaneous DMPM athymic-mice models revealed the marked antitumour activity of the LDH-A inhibitor NHI-Glc-2, alone or combined with gemcitabine.

CONCLUSIONS

This study provides novel insights into hypoxia/PCFT-dependent chemoresistance, unravelling the potential prognostic value of LDH-A, and demonstrating the preclinical activity of LDH-A inhibitors.

Association between lactate dehydrogenase levels and oncologic outcomes in metastatic prostate cancer: A meta-analysis

Purpose

Previous studies have provided evidence of the high expression of lactate dehydrogenase (LDH) in multiple solid tumors; however, its prognostic relationship with metastatic prostate cancer (mPCa) remains controversial. We performed a meta‐analysis to better understand the prognostic potential of LDH in mPCa.

Methods

In our investigation, we included PubMed, Embase, Web of Science, and Cochrane Library as web‐based resources, as well as studies published before January 2020 on the predictive value of LDH in mPCa. We independently screened the studies according to the inclusion and exclusion criteria, evaluated the quality of the literature, extracted the data, and used RevMan 5.3 and STATA12.0 software for analysis.

Result

From the 38 published studies, the records of 9813 patients with mPCa were included in this meta‐analysis. We observed that higher levels of LDH in patients with mPCa were significantly associated with poorer overall survival (OS) (HR = 2.17, 95% CI: 1.91‐2.47, P < .00001) and progression‐free survival (PFS) (HR = 1.60, 95% CI: 1.20‐2.13, P = .001). The subgroup analyses indicated that the negative prognostic impact of higher levels of LDH on the oncologic outcomes of mPCa was significant regardless of ethnicity, publication year, sample size, analysis type, treatment type, age, and disease state.

Conclusion

Our analysis suggested the association between a higher level of LDH and poorer OS and PFS in patients with mPCa. As a parameter that can be conveniently evaluated, the LDH levels should be included as a valuable biomarker in the management of mPCa.

ARNT-dependent CCR8 reprogrammed LDH isoform expression correlates with poor clinical outcomes of prostate cancer

Lactate dehydrogenase isozyme (LDH) is a tetramer constituted of two isoforms, LDHA and LDHB, the expression of which is associated with cell metabolism and cancer progression. Our previous study reveals that CC-chemokine ligand-18 (CCL18) is involved in progression of prostate cancer (PCa).This study aims to investigate how CCL18 regulates LDH isoform expression, and therefore, contributes to PCa progression. The data revealed that the expression of LDHA was upregulated and LDHB was downregulated in PCa cells by CCL18 at both messenger RNA and protein levels. The depletion of CCR8 reduced the ability of CCL18 to promote the proliferation, migration, and lactate production of PCa cells. Depletion of a CCR8 regulated transcription factor, ARNT, significantly reduced the expression of LDHA. In addition, The Cancer Genome Atlas dataset analyses revealed a positive correlation between CCR8 and ARNT expression. Two dimension difference gel electrophoresis revealed that the LDHA/LDHB ratio was increased in the prostatic fluid of patients with PCa and PCa tissues. Furthermore, increased LDHA/LDHB ratio was associated with poor clinical outcomes of patients with PCa. Together, our results indicate that the CCR8 pathway programs LDH isoform expression in an ARNT dependent manner and that the ratio of LDHA/LDHB has the potential to serve as biomarkers for PCa diagnosis and prognosis.

Lactate dehydrogenase: a marker of diminished antitumor immunity

Lactate dehydrogenase (LDH) levels are inversely related with response to checkpoint inhibitors. Elevated LDH levels are the product of enhanced glycolytic activity of the tumor and tumor necrosis due to hypoxia, the latter being associated with high tumor burden. In this review, we elucidate the effects of glycolysis and hypoxia on antitumor immunity and set forth ways to improve response to immunotherapy in cancer patients with elevated LDH levels. We discuss the current knowledge on combining immunotherapy with glycolysis inhibitors, anti-acidifying drugs, anti-angiogenic or cytoreductive therapy.

Intratumoral heterogeneity of glutaminase and lactate dehydrogenase A protein expression in colorectal cancer

The high expression of metabolic enzymes, including glutaminase (GA) and lactate dehydrogenase A (LDHA), which contribute to bioenergetics and biosynthesis of mammalian cells, has been identified in a variety of cancer types. The current study indicated intratumoral heterogeneity with respect to protein expression of the metabolic enzymes in colorectal cancer (CRC). GA protein expression was determined using immunohistochemistry in 98 cases of surgically resected T3 CRC. A total of 75 cases (74%) exhibited moderate to strong immunopositivity of GA based on whole-section examination. A significant correlation was demonstrated between GA expression and clinicopathological features, including histological type and tumor budding in a patient population. Detailed histological analysis revealed the upregulation of GA protein expression at the invasive margin, including tumor budding of CRC tissues. Semi-quantitative examination revealed a significant difference in immunoexpression level of GA between the invasive margin and central CRC. However, LDHA expression exhibited an opposite pattern, with expression elevated at the center and significantly decreased at the tumors invasive margin. Immunohistochemical expression of another glycolytic enzyme hexokinase II was equivalent in both regions. Furthermore, gene silencing of GLS1, which encodes GA protein, and GA inhibitor treatment significantly inhibited cell growth of CRC cell lines. Therefore, the results of the present study demonstrated that the alteration in GA and LDHA expression is more prominent at the invasive margin, which involves tumor budding in CRC.

Application of the ESMACS Binding Free Energy Protocol to a Multi-Binding Site Lactate Dehydogenase A Ligand Dataset

Over the past two decades, the use of fragment-based lead generation has become a common, mature approach to identify tractable starting points in chemical space for the drug discovery process. This approach naturally involves the study of the binding properties of highly heterogeneous ligands. Such datasets challenge computational techniques to provide comparable binding free energy estimates from different binding modes. The performance of a range of statistically robust ensemble-based binding free energy calculation protocols, called ESMACS (enhanced sampling of molecular dynamics with approximation of continuum solvent), is evaluated. Ligands designed to target two binding pockets in the lactate dehydogenase, a target protein, which vary in size, charge, and binding mode, are studied. When compared to experimental results, excellent statistical rankings are obtained across this highly diverse set of ligands. In addition, three approaches to account for entropic contributions are investigated: 1) normal mode analysis, 2) weighted solvent accessible surface area (WSAS), and 3) variational entropy. Normal mode analysis and WSAS correlate strongly with each other-although the latter is computationally far cheaper-but do not improve rankings. Variational entropy corrects exaggerated discrimination of ligands bound in different pockets but creates three outliers which reduce the quality of the overall ranking.

The significance of CO2 combining power in predicting prognosis of patients with stage II and III colorectal cancer

Aim: This study was to evaluate whether CO₂CP level in venous blood could predict prognosis of patients with colorectal cancer (CRC). Materials & methods: A retrospective cohort of 238 patients with CRC who received surgical resection and 176 CRC Stage IV patients were included. A total of 114 healthy people were recruited as control. CO₂CP levels were obtained from medical records. Survival analysis was performed to evaluate CO₂CP predictive potential. The patients were divided into CO₂CP high or low group based on CO₂CP optimal cut-off values. Conclusion: The decreased CO₂CP in CRC patients was associated with advanced clinical stage, and suggested that decreased CO₂CP may predict the worse outcomes of disease-free survival in II/III stage CRC patients.

Malate-aspartate shuttle promotes l-lactate oxidation in mitochondria

Metabolism in cancer cells is rewired to generate sufficient energy equivalents and anabolic precursors to support high proliferative activity. Within the context of these competing drives aerobic glycolysis is inefficient for the cancer cellular energy economy. Therefore, many cancer types, including colon cancer, reprogram mitochondria-dependent processes to fulfill their elevated energy demands. Elevated glycolysis underlying the Warburg effect is an established signature of cancer metabolism. However, there are a growing number of studies that show that mitochondria remain highly oxidative under glycolytic conditions. We hypothesized that activities of glycolysis and oxidative phosphorylation are coordinated to maintain redox compartmentalization. We investigated the role of mitochondria-associated malate-aspartate and lactate shuttles in colon cancer cells as potential regulators that couple aerobic glycolysis and oxidative phosphorylation. We demonstrated that the malate-aspartate shuttle exerts control over NAD⁺ /NADH homeostasis to maintain activity of mitochondrial lactate dehydrogenase and to enable aerobic oxidation of glycolytic l-lactate in mitochondria. The elevated glycolysis in cancer cells is proposed to be one of the mechanisms acquired to accelerate oxidative phosphorylation.

Prognostic role of glycolysis for cancer outcome: evidence from 86 studies

OBJECTIVE

The abnormal expression of the key enzymes in glycolytic pathways, including glucose transporter-1, glucose transporter-3, hexokinase-II, lactate dehydrogenase 5, pyruvate kinase M2, glucose-6-phosphate dehydrogenase, transketolase-like protein 1 and pyruvate dehydrogenase kinase-1 was reported to be associated with poor prognosis of various cancers. However, the association remains controversial. The objective of this study was to investigate the prognostic significance of glycolysis-related proteins.

MATERIALS AND METHODS

We searched MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, using Pubmed and Ovid as search engines and Google Scholar from inception to April 2017. Eighty-six studies with 12,002 patients were included in the study.

RESULTS

Our pooled results identified that glycolysis-related proteins in cancers were associated with shorter overall survival of colorectal cancer (HR 2.33, 95% CI 1.38-3.93, P = 0.002), gastric cancer (HR 1.55, 95% CI 1.31-1.82, P < 0.001), cancer of gallbladder or bile duct (HR 2.16, 95% CI 1.70-2.75, P < 0.001), oral cancer (HR 2.07, 95% CI 1.32-3.25, P < 0.001), esophageal cancer (HR 1.66, 95% CI 1.25-2.21, P = 0.01), hepatocellular carcinoma (HR 2.04, 95% CI 1.64-2.54, P < 0.001), pancreatic cancer (HR 1.72, 95% CI 1.39-2.13, P < 0.001), breast cancer(HR 1.67, 95% CI 1.34-2.08, P < 0.001), and nasopharyngeal carcinoma (HR 3.59, 95% CI 1.75-7.36, P < 0.001). No association was found for lung cancer, ovarian cancer or melanoma. The key glycolytic transcriptional regulators (HIF-1α, p53) were analyzed in parallel to the glycolysis-related proteins, and the pooled results identified that high-level expression of HIF-1α was significantly associated with shorter overall survival (HR 0.57, 95% CI 0.42-0.79, P < 0.001) Furthermore, glycolysis-related proteins linked with poor differentiated tumors (OR 1.81, 95% CI 1.46-2.25, P < 0.001), positive lymph node metastasis (OR 2.73, 95% CI 2.16-3.46, P < 0.001), positive vascular invasion (OR 2.05, 95% CI 1.37-3.07, P < 0.001), large tumor size (OR 2.06, 95% CI 1.80-2.37, P < 0.001), advanced tumor stage (OR 1.58, 95% CI 1.19-2.09, P < 0.001), and deeper invasion (OR 2.37, 95% CI 1.93-2.91, P < 0.001).

CONCLUSION

Glycolytic transcriptional regulators and glycolysis-related proteins in cancers were significantly associated with poor prognosis, suggesting glycolytic status may be potentially valuable prognostic biomarkers for various cancers.

Prognostic Value of Lactate Dehydrogenase in Patients with Hepatocellular Carcinoma: A Meta-Analysis

Background

Previous studies have shown the prognostic value of lactate dehydrogenase (LDH) in hepatocellular carcinoma (HCC), but the results are not persuasive. Therefore, the purpose of our study was to quantitatively explore the prognostic value of LDH in hepatocellular carcinoma.

Methods

We searched the Web of Science, Embase, PubMed, and the Cochrane Library for literature published before October 2018 on the prognostic value of LDH in patients with hepatocellular carcinoma. The combined hazard ratios (HRs) and 95% confidence intervals (CIs) were utilized to assess the prognostic value of LDH in overall survival (OS), recurrence-free survival (RFS), and progression-free survival (PFS) of HCC. Subgroup analysis, sensitivity analysis, and metaregression were used to explore the source of heterogeneity. Funnel plots with Begg's test and Egger's test were used to detect potential publication biases. Furthermore, combined odds ratios (ORs) were utilized to assess the correlation between LDH and clinicopathological features.

Results

A total of 10 nonrandomized controlled studies were included in this meta-analysis. The combined effects of LDH on HCC patients' OS, RFS/DFS, and PFS were HR = 2.07, 95% CI: 1.63-2.62, P < 0.001; HR = 1.62, 95% CI: 1.37-1.90, P < 0.001; and HR = 1.96, 95% CI: 1.14-3.36, P = 0.014, respectively. Subgroup analysis and sensitivity analysis showed that the outcome was stable, and the results of the metaregression also identified statistical models as an important source of heterogeneity. Potential publication bias was detected in the OS studies, so the trim-and-fill method was used to explore publication bias, and the results showed stability. Furthermore, the combined OR suggests that LDH was significantly correlated with gender, Child-Pugh grade, alpha-fetoprotein, vascular invasion, and tumor size.

Conclusions

Preoperative LDH elevation is significantly associated with poor prognosis in patients with HCC, which may be a promising factor in assessing the prognosis of patients with HCC.

Lactate dehydrogenase A: A key player in carcinogenesis and potential target in cancer therapy

Elevated glycolysis remains a universal and primary character of cancer metabolism, which deeply depends on dysregulated metabolic enzymes. Lactate dehydrogenase A (LDHA) facilitates glycolytic process by converting pyruvate to lactate. Numerous researches demonstrate LDHA has an aberrantly high expression in multiple cancers, which is associated with malignant progression. In this review, we summarized LDHA function in cancer research. First, we gave an introduction of structure, location, and basic function of LDHA. Following, we discussed the transcription and activation mode of LDHA. Further, we focused on the function of LDHA in cancer bio-characteristics. Later, we discussed the clinical practice of LDHA in cancer prevention and treatment. What we discussed gives a precise insight into LDHA especially in cancer research, which will contribute to exploring cancer pathogenesis and its handling measures.

CDC25A pathway toward tumorigenesis: Molecular targets of CDC25A in cell-cycle regulation

The cell division cycle 25 (CDC25) phosphatases regulate key transitions between cell-cycle phases during normal cell division, and in the case of DNA damage, they are key targets of the checkpoint machinery that ensure genetic stability. Little is known about the mechanisms underlying dysregulation and downstream targets of CDC25. To understand these mechanisms, we silenced the CDC25A gene in breast cancer cell line MDA-MB-231 and studied downstream targets of CDC25A gene. MDA-MB-231 breast cancer cells were transfected and silenced by CDC25A small interfering RNA. Total messenger RNA (mRNA) was extracted and analyzed by quantitative real-time polymerase chain reaction. CDC25A phosphatase level was visualized by Western blot analysis and was analyzed by 2D electrophoresis and LC-ESI-MS/MS. After CDC25A silencing, cell proliferation reduced, and the expression of 12 proteins changed. These proteins are involved in cell-cycle regulation, programmed cell death, cell differentiation, regulation of gene expression, mRNA editing, protein folding, and cell signaling pathways. Five of these proteins, including ribosomal protein lateral stalk subunit P0, growth factor receptor bound protein 2, pyruvate kinase muscle 2, eukaryotic translation elongation factor 2, and calpain small subunit 1 increase the activity of cyclin D1. Our results suggest that CDC25A controls the cell proliferation and tumorigenesis by a change in expression of proteins involved in cyclin D1 regulation and G1/S transition.

Targeting colorectal cancer cell metabolism through development of cisplatin and metformin nano-cubosomes

Background

Colorectal cancer (CRC) remains a leading cause of death worldwide. Utilizing cisplatin in CRC is correlated with severe adverse effects and drug-resistance. Combined anticancer drug-treatment, along with, their enhanced delivery, can effectively kill cancer through multiple pathways. Nano-cubosomes are emerging as nanocarriers for anticancer therapies, hence, we constructed nano-cubosomes bearing cisplatin and cisplatin-metformin combination for investigation on HCT-116 cells.

Methods

Nano-cubosomes bearing either cisplatin alone or cisplatin-metformin combination were formulated using emulsification technique. The loaded nano-cubosomes were characterized in vitro and the optimized formulation was selected. Their cytotoxic effects were investigated by Sulphorhodamine-B (SRB) assay. The AMPK/mTOR metabolic pathway as well as the Akt/mTOR pathway were analyzed using ELISA technique. Colorimetry was used in NADPH oxidase, LDH and caspase-3 activity determination.

Results

nano-cubosomal formulations exhibited superior cytotoxic effect compared to unformulated cisplatin. This cytotoxic effect was profound upon incorporation of metformin, an indirect mTOR inhibitor, in cisplatin nano-cubosomes. The induced CRC cell apoptosis was through inhibition of several metabolic pathways, namely, AMPK/mTOR and Akt/mTOR. Drug-loaded nano-cubosomes ensued depletion in glucose and energy levels that led to AMPK activation and thus mTOR inhibition. mTOR was additionally inhibited via suppression of p-Akt (Ser473) levels after nano-cubosomal treatment. Moreover, drug-loaded nano-cubosomes produced a notable escalation in ROS levels, evident as an increase in NADPH oxidase, inhibition of LDH and a consequential upsurge in caspase-3.

Conclusion

These results demonstrated the influence exerted by cisplatin-loaded nano-cubosomes on CRC cell survival and enhancement of their cytotoxicity upon metformin addition.

PI3K/Akt and HIF‑1 signaling pathway in hypoxia‑ischemia (Review)

Hypoxia-ischemia (H-I) is frequently observed in perinatal asphyxia and other diseases. It can lead to serious cardiac injury, cerebral damage, neurological disability and mortality. Previous studies have demonstrated that the phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) signaling pathway, which regulates a wide range of cellular functions, is involved in the resistance response to H-I through the activation of proteins associated with survival and inactivation of apoptosis-associated proteins. It can also regulate the expression of hypoxia-induced factor-1α (HIF-1α). HIF-1α can further regulate the expression of downstream proteins involved in glucose metabolism and angiogenesis, such as vascular endothelial growth factor and erythropoietin, to facilitate ischemic adaptation. Notably, HIF-1α may also induce detrimental effects. The effects of HIF-1 on ischemic outcomes may be dependent on the H-I duration, animal age and species. Thus, further investigation of the PI3K/Akt signaling pathway may provide further insights of the potential targets for treating diseases accompanied by H-I.

Downregulation of MCT4 for lactate exchange promotes the cytotoxicity of NK cells in breast carcinoma

Monocarboxylate transporter‐4 (MCT4), a monocarboxylic acid transporter, demonstrates significantly increased expression in the majority of malignancies. We performed an experiment using BALB/C mice, and our results showed that ShMCT4 transfection or the pharmaceutic inhibition of MCT4 with 7acc1 strengthens the activity of NK cells. The results of a calcein assay revealed that the cytotoxicity of NK cells was strengthened via inhibition of MCT4. In addition, ELISA testing showed that the content of perforin and CD107a was increased, and PCR amplification and immunoblotting revealed that the expression of NKG2D and H60 was upregulated after the inhibition of MCT4. Further, we observed an elevated pH value, decreased extracellular lactate flow, and attenuated tumor growth. Therefore, we concluded that the inhibition of MCT4 enhanced the cytotoxicity of NK cells by blocking lactate flux and reversing the acidified tumor microenvironment. In addition to these findings, we also discovered that MCT4 depletion may have a pronounced impact on autophagy, which was surmised by observing that the inhibition of autophagy (3MA) pulled the enhanced cytotoxicity of NK cells downwards. Together, these data suggest that the key effect of MCT4 depletion on NK cells probably utilizes inductive autophagy as a compensatory metabolic mechanism to minimize the acidic extracellular microenvironment associated with lactate export in tumors.

Prognostic factors for operable biliary tract cancer: serum levels of lactate dehydrogenase, a strong association with survival

BACKGROUND

Biliary tract cancers (BTCs) are uncommon but fatal, with a low 5-year survival rate after surgical resection. This study was designed to investigate the prognostic factors for operable BTC.

METHODS

Baseline demographics at diagnosis were retrospectively evaluated in 341 BTC patients undergoing radical surgery at The First Affiliated Hospital of Nanjing Medical University from January 2011 to December 2015. The association between prognostic factors and overall survival (OS) was determined by multivariate analysis using the Cox proportional hazards regression model.

RESULTS

Our study showed that 341 patients were included in the analysis, of which 166 (48.7%) were males and 175 (51.3%) were females. Older age, depth of tumor invasion, positive surgical margin, lower hemoglobin, and higher lactic dehydrogenase (LDH) were associated with significantly worse OS using multivariate analysis. In the entire cohort, the estimate of median OS in patients with LDH <271 U/L was 36.291 months (95% CI; 30.989-41.594 months), and 30.736 months (95% CI; 19.154-42.318 months) in patients with LDH ≥271 U/L (adjusted HR-1.505, 95% CI; 1.009-2.245, P = 0.045). Moreover, it was investigated whether serum LDH retained its significance as a prognostic marker in BTC subgroups separately. The results showed that LDH was prognostic in patients with distal bile duct (DBD) carcinoma undergoing radical surgery (HR-2.452, 95% CI; 1.167-5.152, P = 0.018). However, there were no statistical differences between LDH and OS in multivariate analysis in the other three individual subgroups except for DBD carcinoma. This may be due to the limited number of patients in the study, indicating that a greater number of patients may be required for statistical significance.

CONCLUSION

Older age, depth of tumor invasion, positive surgical margin status, lower hemoglobin levels, and elevated serum LDH level are associated with poor survival in operable BTC patients. Serum LDH level is a cost-effective prognostic biomarker in patients with operable BTC and especially DBD carcinoma.

Clinical laboratory and imaging evidence for effectiveness of agarose-agarose macrobeads containing stem-like cells derived from a mouse renal adenocarcinoma cell population (RMBs) in treatment-resistant, advanced metastatic colorectal cancer: Evaluation of a biological-systems approach to cancer therapy (U.S. FDA IND-BB 10091; NCT 02046174, NCT 01053013)

Objective

The complexity, heterogeneity and capacity of malignant neoplastic cells and tumors for rapid change and evolution suggest that living-cell-based biological-systems approaches to cancer treatment are merited. Testing this hypothesis, the tumor marker, metabolic activity, and overall survival (OS) responses, to the use of one such system, implantable macrobeads [RENCA macrobeads (RMBs)], in phase I and IIa clinical trials in advanced, treatment-resistant metastatic colorectal cancer (mCRC) are described here.

Methods

Forty-eight mCRC patients (30 females; 18 males), who had failed all available, approved treatments, underwent RMB implantation (8 RMB/kg body weight) up to 4 times in phase I and phase IIa open-label trials. Physicals, labs [tumor and inflammation markers, lactate dehydrogenase (LDH)] and positron emission tomography-computed tomography (PET-CT) imaging to measure number/volume and metabolic activity of the tumors were performed pre- and 3-month-post-implantation to evaluate safety and initial efficacy (as defined by biological responses). PET-CT maximum standard uptake value (SUV_max) (baseline and d 90; SUV_max ≥2.5), LDH, and carcinoembryonic antigen (CEA) and/or cancer antigen 19-9 (CA 19-9) response (baseline, d 30 and/or d 60) were assessed and compared to OS.

Results

Responses after implantation were characterized by an at least 20% decrease in CEA and/or CA 19-9 in 75% of patients. Fluorodeoxyglucose (FDG)-positive lesions (phase I, 39; 2a, 82) were detected in 37/48 evaluable patients, with 35% stable volume and stable or decreased SUV (10) plus four with necrosis; 10, increased tumor volume, SUV. LDH levels remained stable and low in Responders (R) (d 0-60, 290.4-333.9), but increased steadily in Non-responders (NR) (d 0-60, 382.8-1,278.5) (d 60, P=0.050). Responders to RMBs, indicated by the changes in the above markers, correlated with OS (R mean OS=10.76 months; NR mean OS=4.9 months; P=0.0006).

Conclusions

The correlations of the tumor marker, tumor volume and SUV changes on PET-CT, and LDH levels themselves, and with OS, support the concept of a biological response to RMB implantation and the validity of the biological-systems approach to mCRC. A phase III clinical trial is planned.

Mitochondrial pyruvate carrier function is negatively linked to Warburg phenotype in vitro and malignant features in esophageal squamous cell carcinomas

Aerobic glycolysis is one of the emerging hallmarks of cancer cells. In this study, we investigated the relationship between blocking mitochondrial pyruvate carrier (MPC) with MPC blocker UK5099 and the metabolic alteration as well as aggressive features of esophageal squamous carcinoma. It was found that blocking pyruvate transportation into mitochondria attenuated mitochondrial oxidative phosphorylation (OXPHOS) and triggered aerobic glycolysis, a feature of Warburg effect. In addition, the HIF-1α expression and ROS production were also activated upon UK5099 application. It was further revealed that the UK5099-treated cells became significantly more resistant to chemotherapy and radiotherapy, and the UK5099-treated tumor cells also exhibited stronger invasive capacity compared to the parental cells. In contrast to esophageal squamous epithelium cells, decreased MPC protein expression was observed in a series of 157 human squamous cell carcinomas, and low/negative MPC1 expression predicted an unfavorable clinical outcome. All these results together revealed the potential connection of altered MPC expression/activity with the Warburg metabolic reprogramming and tumor aggressiveness in cell lines and clinical samples. Collectively, our findings highlighted a therapeutic strategy targeting Warburg reprogramming of human esophageal squamous cell carcinomas.

The promise and challenges of exploiting the proton-coupled folate transporter for selective therapeutic targeting of cancer

This review considers the "promise" of exploiting the proton-coupled folate transporter (PCFT) for selective therapeutic targeting of cancer. PCFT was discovered in 2006 and was identified as the principal folate transporter involved in the intestinal absorption of dietary folates. The recognition that PCFT was highly expressed in many tumors stimulated substantial interest in using PCFT for cytotoxic drug targeting, taking advantage of its high level transport activity under the acidic pH conditions that characterize many tumors. For pemetrexed, among the best PCFT substrates, transport by PCFT establishes its importance as a clinically important transporter in malignant pleural mesothelioma and non-small cell lung cancer. In recent years, the notion of PCFT-targeting has been extended to a new generation of tumor-targeted 6-substituted pyrrolo[2,3-d]pyrimidine compounds that are structurally and functionally distinct from pemetrexed, and that exhibit near exclusive transport by PCFT and potent inhibition of de novo purine nucleotide biosynthesis. Based on compelling preclinical evidence in a wide range of human tumor models, it is now time to advance the most optimized PCFT-targeted agents with the best balance of PCFT transport specificity and potent antitumor efficacy to the clinic to validate this novel paradigm of highly selective tumor targeting.

TOP1MT deficiency promotes GC invasion and migration via the enhancements of LDHA expression and aerobic glycolysis

Aerobic glycolysis plays an important role in cancer progression. New target genes regulating cancer aerobic glycolysis must be explored to improve patient prognosis. Mitochondrial topoisomerase I (TOP1MT) deficiency suppresses glucose oxidative metabolism but enhances glycolysis in normal cells. Here, we examined the role of TOP1MT in gastric cancer (GC) and attempted to determine the underlying mechanism. Using in vitro and in vivo experiments and analyzing the clinicopathological characteristics of patients with GC, we found that TOP1MT expression was lower in GC samples than in adjacent nonmalignant tissues. TOP1MT knockdown significantly promoted GC migration and invasion in vitro and in vivo Importantly, TOP1MT silencing increased glucose consumption, lactate production, glucose transporter 1 expression and the epithelial-mesenchymal transition (EMT) in GC. Additionally, regulation of glucose metabolism induced by TOP1MT was significantly associated with lactate dehydrogenase A (LDHA) expression. A retrospective analysis of clinical data from 295 patients with GC demonstrated that low TOP1MT expression was associated with lymph node metastasis, recurrence and high mortality rates. TOP1MT deficiency enhanced glucose aerobic glycolysis by stimulating LDHA to promote GC progression.

Predictive clinical parameters for the response of nivolumab in pretreated advanced non-small-cell lung cancer

Background

Nivolumab offers a superior survival benefit over docetaxel in patients with advanced, previously treated non-small-cell lung cancer (NSCLC). An association between programmed cell death ligand-1 (PD-L1) expression and the efficacy of nivolumab has been reported in many studies. However, the association between the clinical parameters and efficacy of nivolumab remains unclear in advanced NSCLC patients.

Results

Among 124 patients, 108 (88%) were performance status (PS) 0 to 1. PD-L1 expression was assessed in 89 patients, with 51 (57%) patients having PD-L1 positive expression. In all patients, the objective response rate (ORR) in patients with elevated CRP levels (≥ 1 mg/dl) was significantly worse than those without elevated CRP levels (< 1 mg/dl) (8.3 vs 23.4%, p = 0.0180). The PS (≥ 2), smoking index (< 400), CRP levels (≥ 1 mg/dl) and LDH (≥ 245 IU/L) were significantly associated with a shorter PFS and OS in patients treated with nivolumab. Multivariate analyses showed that the PS (≥ 2), smoking index (< 400), CRP levels (≥ 1 mg/dl) and LDH (≥ 245 IU/L) and PD-L1 expression were significant factors associated with a longer PFS of nivolumab.

Materials and Methods

We retrospectively analyzed 124 patients who received nivolumab as a subsequent treatment. The patient characteristics, laboratory data at baseline (C-reactive protein [CRP] and lactate dehydrogenase [LDH]), PD-L1 expression, nivolumab response, progression-free survival (PFS), and overall survival (OS) were evaluated.

Conclusions

Clinical parameters, such as PS, serum CRP, serum LDH, and smoking status, were significantly associated with the response duration and survival in patients treated with nivolumab.

Blocking LDHA glycolytic pathway sensitizes glioblastoma cells to radiation and temozolomide

PURPOSE

Up-regulation of lactate dehydrogenase LDHA, is a frequent event in human malignancies and relate to poor postoperative outcome. In the current study we examined the hypothesis that LDHA and anaerobic glycolysis, may contribute to the resistance of glioblastoma to radiotherapy and to temozolomide.

METHODS AND MATERIALS

The expression of LDH5 isoenzyme (fully encoded by the LDHA gene) was assessed in human glioblastoma tissues. Experimental in vitro studies involved the T98 and U87 glioblastoma cell lines. Their sensitivity to radiotherapy and to temozolomide, following silencing of LDHA gene or following exposure to the LDHA chemical inhibitor 'oxamate' and to the glycolysis inhibitor '2-deoxy-d-glucose' (2DG), was studied.

RESULTS

Glioblastoma tissues showed strong cytoplasmic and nuclear LDH5 expression in 0-90% (median 20%) of the neoplastic cells. T98 and U87 cell lines showed that blocking glycolysis, either with LDHA gene silencing or exposure to oxamate (30 mM) and blockage of glycolysis with 2DG (500 μM), results in enhanced radiation sensitivity, an effect that was more robust in the T98 radioresistant cell line. Furthermore, all three glycolysis targeting methods, significantly sensitized both cell lines to Temozolomide.

CONCLUSIONS

The current study provides evidence that a large subgroup of human glioblastomas are highly glycolytic, and that inhibitors of glycolysis, like LDHA targeting agents, may prove of therapeutic importance by enhancing the efficacy of radiotherapy and temozolomide against this lethal disease.

Tumor LDH-A expression and serum LDH status are two metabolic predictors for triple negative breast cancer brain metastasis

There are limited therapeutic methods for triple negative breast cancer in the clinic, which is easy to progress into the brain to form metastatic lesions and evolve into the terminal stage. Because both the primary cancer and the brain metastasis have high glycolysis, we hypothesize that lactate dehydrogenase (LDH), which catalyzes the final step of glycolysis, may be a predictor, as well as a treatment target, for breast cancer brain metastasis. Therefore, the expression of LDH-A was detected on 119 triple negative breast cancer tissues with immunohistochemistry, and the serum LDH levels were also measured. Our results showed that the LDH-A expression inside the tumor was significantly higher than the matched normal tissues. Tumor LDH-A expression, serum LDH status, and the slope of serum LDH status were closely associated with triple negative breast cancer brain metastasis and brain metastasis free survival. This study indicates that tumor LDH and serum LDH status are two predictors for triple negative breast cancer brain metastasis.

Expression of enzymes related to glucose metabolism in non-small cell lung cancer and prognosis

Purpose/Aim: Cancer cells are addicted to glycolytic anaerobic pathways, in presence or in absence of a functional Krebs' cycle (phenomenon Warburg). This metabolic predilection relies on both extracellular (impaired vascularization and oxygenation) and intracellular (oncogenic activation of genes) causes.

MATERIALS AND METHODS

We investigated the expression and prognostic relevance of enzymes involved in the glucose absorption and metabolism, monocarboxylate transporter (MCT) expression, MCT1 and MCT2, pentose pathway (Glucose-6-phospahte dehydrogenase G6PD), glycogene synthesis (glycogene synthase GYS1), glycolysis (Hexokinase HXKII, phosphofructokinase PFK1, fructose biphosphate aldolase), fate of pyruvate (pyruvate dehydrogenase PDH, phosphorylated pPDH, PDH kinase PDK1, lactate dehydrogenase LDH5 and LDH1) and key Kreb's cycle enzymes (citrate synthase CSynth and isocitrate dehydrogenase IDH).

RESULTS

A strong overexpression of the above enzymes/proteins was noted in a varying percentage of cases examined. An interesting significant correlation between the enzymes involved in glycolysis and with the LDH5 was noted. Adenocarcinomas expressed higher levels of GLUT1 and MCT2 compared to other subtypes. Stage (p = 0.0001), aldolase (p = 0.004), LDH5 (p = 0.008), GLUT2 (p = 0.008), MCT2 (p = 0.009), GSYS1 (p = 0.04), and GLUT1 (p = 0.05) were significantly related with poor disease specific overall survival. In multivariate analysis stage (p = 0.001), LDH5 (p = 0.04), pPDH (p = 0.04), and aldolase (p = 0.04) were independent prognostic variables.

CONCLUSION

It is concluded that an orchestrated activation of glucose absorption and metabolism towards anaerobic pathways characterize the majority of NSCLC, and this phenotype is strongly linked with an aggressive clinical behavior. This glycolytic addiction of lung cancer cell is revealed as a key therapeutic target.

HIF1/2α mediates hypoxia-induced LDHA expression in human pancreatic cancer cells

Glycolysis is a typical conduit for energy metabolism in pancreatic cancer (PC) due to the hypoxic microenviroment. Lactate dehydrogenase A (LDHA) catalyzes the conversion of pyruvate to lactate and is considered to be a key checkpoint of anaerobic glycolysis. The aim of the present study was to explore the mechanism of interactions between hypoxia, HIF-1/2α and LDHA, and the function of LDHA on PC cells by analyzing 244 PC and paratumor specimens. It was found that LDHA was over-expressed and related to tumor stages. The result of in vitro study demonstrated that hypoxia induced LDHA expression. To explore the relationship between HIF and LDHA, chromatin immunoprecipitation assay and luciferase assay were performed. The result showed that HIF-1/2α bound to LDHA at 89bp under the hypoxic condition. Furthermore, knockdown of endogenous HIF-1α and HIF-2α decreased the LDHA expression even in the hypoxic condition, which was accompanied with a significant decrease in lactate production and glucose utilization (p < 0.01). Immunofluorescence in the 244 specimens showed that HIF-1/2α was over-expressed and associated with LDHA over-expression (p < 0.0001). Forced expression of LDHA promoted the growth and migration of PC cells, while knocking down the expression of LDHA inhibited the cell growth and migration markedly. In summary, the present study proved that HIF1/2α could activate LDHA expression in human PC cells, and high expression of LDHA promoted the growth and migration of PC cells.

Early evaluation of sunitinib for the treatment of advanced gastroenteropancreatic neuroendocrine neoplasms via CT imaging: RECIST 1.1 or Choi Criteria?

Background

The aim of this study was to assess and compare the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) and the Choi criteria in evaluating the early response of advanced gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) treated with sunitinib.

Methods

Eighteen patients with pathologically proven advanced GEP-NENs treated with sunitinib were enrolled in the study. Pre- and post-treatment CT scans (plain, biphasic enhanced CT scan) were performed on all patients. Changes in the target tumor size and density from pre-treatment to 1.4–3.1 months after treatment were measured and recorded for each patient. Tumor responses were identified using RECIST 1.1 and Choi criteria. The time to tumor progression (TTP) for each patient was measured and compared between groups using the Kaplan-Meier method.

Results

Among the 18 patients, 4 (22%) exhibited a partial response (PR), 9 (50%) exhibited stable disease (SD), and 5 (28%) experienced progressive disease (PD), using RECIST 1.1. However, based on the Choi criteria, 8 (44%) patients exhibited a PR, 4 (22%) exhibited SD, and 6 (33%) experienced PD. According to RECIST 1.1, the median TTP of PR, SD and PD group were 16.6, 10.8 and 2.3 months, respectively. The TTP of the PR group was significantly longer than that of the PD group (P = 0.007) but insignificant when compared to the SD group (P = 0.131). According to Choi criteria, the median TTP of PR, SD and PD group were not reached, 10.8 and 2.3 months, respectively. The TTP of the PR group was significantly longer than that of the SD (P = 0.026) and PD groups (P < 0.001).

Conclusion

The Choi criteria appear to be more sensitive and more precise than RECIST 1.1 in assessing the early response of advanced GEP-NENs treated with sunitinib.

Prognostic relevance of lactate dehydrogenase in advanced pancreatic ductal adenocarcinoma patients

Background

The prognostic role of pretreatment serum lactate dehydronegase (LDH) has been well established in many malignant tumors, albeit it remains under-discussed in pancreatic cancer. In the present study, we aimed to assess the association between baseline LDH levels and overall survival (OS) in advanced pancreatic ductal adenocarcinoma (PDAC) patients who did and did not receive subsequent chemotherapy.

Methods

In total, 135 retrospectively determined patients with locally advanced or metastatic PDAC, who were diagnosed between 2012 and 2013, were analyzed. Baseline LDH levels were detected within 20 days after histopathological confirmation of the diagnosis. Multivariate Cox proportional hazards regression model was applied to estimate the adjusted hazards ratio (HR) for LDH levels and OS of PDAC. We used restricted cubic spline (RCS) to further investigate dose-effect relationship in the association.

Results

Having adjusted for possible confounders, we found that in advanced PDAC patients who went through subsequent chemotherapy, an elevated pretreatment LDH level (≥250 U/L) had an adjusted HR of 2.47 (95% CI = 1.28–4.77) for death, but patients, who did not receive chemotherapy, had no significant HR (adjusted HR = 1.57; 95% CI = 0.83–2.96). RCS fitting results revealed a steep increase in HR for PDAC patients received chemotherapy with a baseline LDH > 500 U/L.

Conclusions

Pretreatment LDH levels had noticeable prognostic value in PDAC patients who received subsequent chemotherapy. Tackling elevated LDH levels before the initiation of chemotherapy might be a promising measure for improving OS of patients after treatment for their advanced PDAC. Studies with a large sample size and a prospective design are warranted to substantiate our findings.