Lactate Dehydrogenase A or B Knockdown Reduces Lactate Production and Inhibits Breast Cancer Cell Motility in vitro

Lactate Is a Major Promotor of Breast Cancer Cell Aggressiveness

Background: Lactate dehydrogenase (LDH) activity, producing high levels of lactate from pyruvate in cancer cells, is often associated with poor patient prognosis. We previously showed enhanced LDH/lactate levels in estrogen receptor (ER) compared to ER + breast cancer cells; lactate or pyruvate supplementation to ER + cells significantly enhanced their motile ability, while LDHB gene knockout (KO) or treatment with LDH inhibitors reduced the motility of the highly aggressive ER breast cancer cells. Aims: To investigate the molecular mechanisms by which lactate, LDHB KO, or treatment with LDH inhibitors can modulate the motile capabilities of breast cancer cell lines. Methods: KO experiments were performed using siRNA, and global expression was determined by proteomic profiling with Proteome Profiler Human XL Oncology arrays, Western blot, and immunofluorescence. Results: Lactate supplementation to ER + breast cancer cells enhanced expression of vimentin, N-cadherin, and snail, while reducing the expression of JAM-A, E-cadherin, and nectin-4. This expression profile was reversed with LDHB KO in ER cells. LDHB KO, or treatment with LDH inhibitors in ER cells, also reduced the expression of IL-6, IL-8, and MMP-2. The expressions of other markers such as PECAM-1, CCL20, and ENPP-2 were differentially modulated with LDH B KO in de novo ER cells (MDA-MB-231) vs. those that had ER knockout (pII). Conclusions: Our data show a novel role for lactate in modulating the EMT status in breast cancer cells and highlight the important role of lactate in breast cancer motility in part through modulating EMT status and the expression profile of cytokines, adhesion molecules, MMP-2, and nectin-4.

Lactic acid metabolism: gynecological cancer's Achilles' heel

Lactic acid is significantly expressed in many cancers, including gynecological cancer, and has become a key regulator of the proliferation, development, metastasis and invasion of these cancers. In clinical and experimental studies, the level of lactic acid in gynecological cancer is closely related to metastasis and invasion, tumor recurrence and poor prognosis. Lactic acid can regulate the internal metabolic pathway of gynecological cancer cells and drive the autonomous role of non-cancer cells in gynecological cancer. In addition to being used as a source of energy metabolism by gynecological cancer cells, lactic acid can also be transported from cancer cells to neighboring cancer cells, stroma and vascular endothelial cells (ECs) to further guide metabolic reprogramming. Lactic acid is also involved in promoting inflammation and angiogenesis in gynecologic tumors. Therefore, we reviewed the mechanisms and recent advances in the production and transport of lactic acid in gynecological cancer. These advances and evidence suggest that targeted lactic acid metabolism is a promising cancer treatment.

Intranuclear TCA and mitochondrial overload: The nascent sprout of tumors metabolism

Abnormal glucose metabolism in tumors is a well-known form of metabolic reprogramming in tumor cells, the most representative of which, the Warburg effect, has been widely studied and discussed since its discovery. However, contradictions in a large number of studies and suboptimal efficacy of drugs targeting glycolysis have prompted us to further deepen our understanding of glucose metabolism in tumors. Here, we review recent studies on mitochondrial overload, nuclear localization of metabolizing enzymes, and intranuclear TCA (nTCA) in the context of the anomalies produced by inhibition of the Warburg effect. We provide plausible explanations for many of the contradictory points in the existing studies, including the causes of the Warburg effect. Furthermore, we provide a detailed prospective discussion of these studies in the context of these new findings, providing new ideas for the use of nTCA and mitochondrial overload in tumor therapy.

Angiotensin 1-7 and the Non-Peptide MAS-R Agonist AVE0991 Inhibit Breast Cancer Cell Migration and Invasion

Background: Endocrine resistance in breast cancer is associated with the epithelial-to-mesenchymal transition (EMT), resulting in enhanced cell proliferation, motility, and invasion and leading to a poor prognosis. There are few studies regarding the role of Angiotensin II (Ang II) and Angiotensin 1-7 (Ang 1-7) in relation to breast cancer, with contradictory outcomes. This study aims to investigate the expression of Ang 1-7 and MAS-R and evaluate the effects of Ang II, Ang 1-7, and the MAS-R agonist AVE0991 on EMT induction and reversal. Methods: The effects of Ang II and Ang 1-7 on normal and breast cancer cell lines were determined using various techniques for cell proliferation (MTT), motility (scratch assay), and invasion (Cultrex assay). Also, the expression/localization profiles of Ang 1-7 and its receptor (MAS-R), as well as various EMT markers, were determined using immunofluorescence, western blot, and ELISA. Results: Ang II significantly decreased the motility of the tested cell lines; however, it did not have a significant effect on their proliferation or invasion. The expression profiles of the tested EMT markers were not affected by Ang II treatment. The expression levels of Ang 1-7 and MAS-R were significantly higher in the normal breast epithelial cells and estrogen receptor ER compared to the ER+ breast cancer cells. Treatment with Ang 1-7 or the non-peptide MAS-R agonist AVE0991 significantly reduced the migration and invasion of the tested cell lines without modulating the tested EMT markers. Compared to Ang 1-7, AVE0991 exhibited a more prominent dose-dependent inhibitory effect on the proliferation, motility, and invasion of the ER- breast cancer cells. Conclusions: Ang 1-7 and AVE0991 play a promising therapeutic role in breast cancer, in part by reducing cell motility and invasion.

Lactate Dehydrogenase-A-Forming LDH5 Promotes Breast Cancer Progression

Background

Breast cancer (BC) has become the main malignant tumor threatening the health of women worldwide. Previous studies have reported that Lactate dehydrogenase-A (LDHA) has critical roles in cancer development and progression. We aimed to explore the roles of LDHA and LDH5 isoenzyme activity in BC, which provides a new insight into LDHA for the treatment of BC.

Methods

The expression of LDHA in BC and its relationship with clinicopathological features were obtained from various databases including The Cancer Genome Atlas (TCGA), Human Protein Atlas (HPA), Breast Cancer-Gene Expression Miner (bc-GenExMiner), TNMplot, UALCAN. The Kaplan‒Meier Plotter was used to evaluate the prognostic value of LDHA. Western blot was performed to detect LDHA expression. Agarose gel electrophoresis was performed to detect the activities of LDH isoenzymes. The in vitro proliferation, migration and invasion potentials of BC cells were evaluated using MTT assays, colony formation, wound-healing assay, matrix metalloproteinase assays and transwell assays, respectively. The activities of LDH isoenzymes in serum and tissues were measured in patients with BC and healthy controls.

Results

Compared to normal tissues, LDHA expression was significantly higher in BC tissues. Patients' nodal status, histological types, TP53 mutation status and PAM50 subtypes were significant factors influencing the LDHA expression. By overexpressing or silencing LDHA gene in BT549 cells, it was confirmed that LDHA promoted cell proliferation, migration and invasion. LDH5 isoenzyme activity in patients with BC was higher than healthy controls. The increased activity of LDH5 isoenzymes was induced by overexpression of LDHA in BC. High expression of LDHA was found to be associated with poor prognosis in BC.

Conclusion

LDHA plays a critical role in the progression of BC through the regulation of the activity of LDH5 isoenzyme, indicating that LDHA may serve as a valuable target for BC treatment.

The synergistic anti-Warburg efficacy of temozolomide, metformin and epigallocatechin gallate in glioblastoma

An important hallmark of glioblastoma aggressiveness is its altered metabolism of glucose. This metabolic shift wherein the tumor cells employ aerobic glycolysis regardless of oxygen availability via reprogramming of mitochondrial oxidative phosphorylation is known as the Warburg effect. Previous literatures have linked this metabolic reprograming to tumor progression and glioblastoma cell proliferation making it a key target for targeted drug therapy. Based on this lacuna, the current study aimed to explore the therapeutic efficacy of the triple-drug combination of temozolomide, metformin and epigallocatechin gallate in attenuating Warburg effect and glucose uptake in glioblastoma both in vitro and in vivo. Our results showed that the triple-drug combination had significantly reduced glucose uptake and reversed the Warburg effect in glioblastoma cells and in the glioma-induced xenograft rat model. Thus, the triple-drug combination would serve as an effective therapeutic regime to hamper glioblastoma progression via altering glucose metabolism and improving the overall prognosis in patient setting.

Dextran-Graft-Polyacrylamide/Zinc Oxide Nanoparticles Inhibit of Cancer Cells in vitro and in vivo

Introduction

Tumor drug resistance and systemic toxicity are major challenges of modern anticancer therapy. Nanotechnology makes it possible to create new materials with the required properties for anticancer therapy.

Methods

In this research, Dextran-graft-Polyacrylamide/ZnO nanoparticles were used. The study was carried out using prostate (DU-145, LNCaP, PC-3), breast (MDA-MB-231, MCF-7, MCF-7 Dox) cancer cells and non-malignant (MAEC, BALB/3T3 clone A31) cells. Zinc was visualized with fluorescence in vitro and in vivo. ROS and apoptotic markers were identified by cytometry. Zinc accumulation and histopathological changes in the tumor, liver, kidney, and spleen were evaluated in a rat model.

Results

ZnO nanoparticles dissociation and release of Zn2+ into the cytosol occurs in 2-3 hours for cancerous and non-cancerous cells. ROS upregulation was detected in all cells. For non-malignant cells, the difference between the initial ROS level was insignificant. The rate of carbohydrate metabolism in cancer cells was reduced by nanosystems. Zinc level in the tumor was upregulated by 25% and 39% after treatment with nanosystems and doxorubicin combined, respectively. The tumor Walker-256 carcinosarcoma volume was reduced twice following mono-treatment with the nanocomplex and 65-fold lower when the nanocomplex was combined with doxorubicin compared with controls. In the liver, kidney and spleen, the zinc level increased by 10-15% but no significant pathological alterations in the tissues were detected.

Conclusion

D-PAA/ZnO NPs nanosystems were internalized by prostate, breast cancer cells and non-malignant cells via endocytosis after short time, but cytotoxicity against non-cancer cells were significantly lower in vitro and in vivo. D-PAA/ZnO NPs nanocomplex efficiently promoted cell death of tumor cells without showing cytotoxicity against non-malignant cells making it a promising anti-cancer agent.

The signature of extracellular vesicles in hypoxic breast cancer and their therapeutic engineering

Breast cancer (BC) currently ranks second in the global cancer incidence rate. Hypoxia is a common phenomenon in BC. Under hypoxic conditions, cells in the tumor microenvironment (TME) secrete numerous extracellular vesicles (EVs) to achieve intercellular communication and alter the metabolism of primary and metastatic tumors that shape the TME. In addition, emerging studies have indicated that hypoxia can promote resistance to tumor treatment. Engineered EVs are expected to become carriers for cancer treatment due to their high biocompatibility, low immunogenicity, high drug delivery efficiency, and ease of modification. In this review, we summarize the mechanisms of EVs in the primary TME and distant metastasis of BC under hypoxic conditions. Additionally, we highlight the potential applications of engineered EVs in mitigating the malignant phenotypes of BC cells under hypoxia.

TRIM27 revealing by tumor educated platelet RNA-sequencing, as a potential biomarker for malignant ground-glass opacities diagnosis mediates glycolysis of non-small cell lung cancer cells partially through HOXM1

Background

Efficient ground-glass opacities (GGOs) diagnosis is challenging. A diagnostic method distinguishing malignant from benign GGOs is warranted. In this study, we sought to construct a noninvasive method based on tumor educated platelet (TEP) RNA profiles for malignant GGOs diagnosis and explore the molecular mechanism of the potential biomarker for the first time.

Methods

Based on TEP RNA-sequencing (TEP RNA-seq) in benign and malignant GGOs, a classification model was constructed using differentially expressed genes (DEGs) and was used to evaluate diagnostic performance. High-throughput quantitative polymerase chain reaction (HT-qPCR) verified 23 genes selected from the top 60 DEGs between benign and malignant GGOs. The correlation between 17 verified DEGs and 22 key glycolytic genes was analyzed. Tripartite motif-containing 27 (TRIM27) overexpressing and knockdown (KD) cell models were constructed using A549 and PC-9 cells, respectively in which cell growth, apoptosis, migration and invasion were evaluated. The protein levels of HK-1/2, PKM1/2, LDHA and GLUT1 were evaluated by western blot. Glycolysis was evaluated through adenosine triphosphate (ATP), reactive oxygen species (ROS), lactate acid (LD) production, glucose uptake, and lactate dehydrogenase (LDH) activity assays. RNA-seq was performed in loss-of TRIM27-KD PC-9 cells to clarify the downstream factors of TRIM27 which was verified using western blot and immunofluorescence double staining.

Results

In 81 samples, the 1,647-DEG-based classification model exhibited area under the curve (AUC), sensitivity, and specificity values of 0.99 [95% confidence interval (CI): 0.972-1.000], 100%, and 91%, respectively, while the top 60-DEG-based classification model exhibited AUC, sensitivity, and specificity values of 0.986 (95% CI: 0.962-1.000), 98%, and 91%, respectively. TRIM27 achieved AUC of 0.87 in the diagnosis of malignant GGOs, with 83.93% sensitivity, 78.79% specificity, 81.15% accuracy, 77.05% positive predictive value (PPV) and 85.25% negative predictive value (NPV). TRIM27 was highly expressed in non-small cell lung cancer (NSCLC) cells, and accelerated cell migration and invasion. In addition, TRIM27 was found to promote glycolysis in NSCLC cells partially through HMOX1 which was negatively correlated with TRIM27.

Conclusions

We constructed a novel TEP RNA-seq based classifier for malignant GGOs diagnosis. TRIM27, an important target discovered, could accelerate migration, invasion and regulate glycolysis partially through HMOX1 in NSCLC cells, thus providing scientific support for TRIM27 as a diagnostic biomarker for malignant GGO diagnosis.

Glycolytic enzymes in non-glycolytic web: functional analysis of the key players

To survive in the tumour microenvironment, cancer cells undergo rapid metabolic reprograming and adaptability. One of the key characteristics of cancer is increased glycolytic selectivity and decreased oxidative phosphorylation (OXPHOS). Apart from ATP synthesis, glycolysis is also responsible for NADH regeneration and macromolecular biosynthesis, such as amino acid biosynthesis and nucleotide biosynthesis. This allows cancer cells to survive and proliferate even in low-nutrient and oxygen conditions, making glycolytic enzymes a promising target for various anti-cancer agents. Oncogenic activation is also caused by the uncontrolled production and activity of glycolytic enzymes. Nevertheless, in addition to conventional glycolytic processes, some glycolytic enzymes are involved in non-canonical functions such as transcriptional regulation, autophagy, epigenetic changes, inflammation, various signaling cascades, redox regulation, oxidative stress, obesity and fatty acid metabolism, diabetes and neurodegenerative disorders, and hypoxia. The mechanisms underlying the non-canonical glycolytic enzyme activities are still not comprehensive. This review summarizes the current findings on the mechanisms fundamental to the non-glycolytic actions of glycolytic enzymes and their intermediates in maintaining the tumor microenvironment.

The determinants of metabolic discrepancies in aerobic glycolysis: Providing potential targets for breast cancer treatment

Altered aerobic glycolysis is the robust mechanism to support cancer cell survival and proliferation beyond the maintenance of cellular energy metabolism. Several investigators portrayed the important role of deregulated glycolysis in different cancers, including breast cancer. Breast cancer is the most ubiquitous form of cancer and the primary cause of cancer death in women worldwide. Breast cancer with increased glycolytic flux is hampered to eradicate with current therapies and can result in tumor recurrence. In spite of the low order efficiency of ATP production, cancer cells are highly addicted to glycolysis. The glycolytic dependency of cancer cells provides potential therapeutic strategies to preferentially kill cancer cells by inhibiting glycolysis using antiglycolytic agents. The present review emphasizes the most recent research on the implication of glycolytic enzymes, including glucose transporters (GLUTs), hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase-A (LDHA), associated signalling pathways and transcription factors, as well as the antiglycolytic agents that target key glycolytic enzymes in breast cancer. The potential activity of glycolytic inhibitors impinges cancer prevalence and cellular resistance to conventional drugs even under worse physiological conditions such as hypoxia. As a single agent or in combination with other chemotherapeutic drugs, it provides the feasibility of new therapeutic modalities against a wide spectrum of human cancers.

Targeting metabolism of breast cancer and its implications in T cell immunotherapy

Breast cancer is a prominent health issue amongst women around the world. Immunotherapies including tumor targeted antibodies, adoptive T cell therapy, vaccines, and immune checkpoint blockers have rejuvenated the clinical management of breast cancer, but the prognosis of patients remains dismal. Metabolic reprogramming and immune escape are two important mechanisms supporting the progression of breast cancer. The deprivation uptake of nutrients (such as glucose, amino acid, and lipid) by breast cancer cells has a significant impact on tumor growth and microenvironment remodeling. In recent years, in-depth researches on the mechanism of metabolic reprogramming and immune escape have been extensively conducted, and targeting metabolic reprogramming has been proposed as a new therapeutic strategy for breast cancer. This article reviews the abnormal metabolism of breast cancer cells and its impact on the anti-tumor activity of T cells, and further explores the possibility of targeting metabolism as a therapeutic strategy for breast cancer.

Lactate dehydrogenase A regulates tumor-macrophage symbiosis to promote glioblastoma progression

Abundant macrophage infiltration and altered tumor metabolism are two key hallmarks of glioblastoma. By screening a cluster of metabolic small-molecule compounds, we show that inhibiting glioblastoma cell glycolysis impairs macrophage migration and lactate dehydrogenase inhibitor stiripentol emerges as the top hit. Combined profiling and functional studies demonstrate that lactate dehydrogenase A (LDHA)-directed extracellular signal-regulated kinase (ERK) pathway activates yes-associated protein 1 (YAP1)/ signal transducer and activator of transcription 3 (STAT3) transcriptional co-activators in glioblastoma cells to upregulate C-C motif chemokine ligand 2 (CCL2) and CCL7, which recruit macrophages into the tumor microenvironment. Reciprocally, infiltrating macrophages produce LDHA-containing extracellular vesicles to promote glioblastoma cell glycolysis, proliferation, and survival. Genetic and pharmacological inhibition of LDHA-mediated tumor-macrophage symbiosis markedly suppresses tumor progression and macrophage infiltration in glioblastoma mouse models. Analysis of tumor and plasma samples of glioblastoma patients confirms that LDHA and its downstream signals are potential biomarkers correlating positively with macrophage density. Thus, LDHA-mediated tumor-macrophage symbiosis provides therapeutic targets for glioblastoma.

Systematic analysis of the role of LDHs subtype in pan-cancer demonstrates the importance of LDHD in the prognosis of hepatocellular carcinoma patients

BACKGROUND

Lactate dehydrogenase (LDHs) is an enzyme involved in anaerobic glycolysis, including LDHA, LDHB, LDHC and LDHD. Given the regulatory role in the biological progression of certain tumors, we analyzed the role of LDHs in pan-cancers.

METHODS

Cox regression, Kaplan-Meier curves, Receiver Operating Characteristic (ROC) curves, and correlation of clinical indicators in tumor patients were used to assess the prognostic significance of LDHs in pan-cancer. The TCGA, HPA, TIMER, UALCAN, TISIDB, and Cellminer databases were used to investigate the correlation between the expression of LDHs and immune subtypes, immune checkpoint genes, methylation levels, tumor mutational load, microsatellite instability, tumor-infiltrating immune cells and drug sensitivity. The cBioPortal database was also used to identify genomic abnormalities of LDHs in pan-cancer. A comprehensive assessment of the biological functions of LDHs was performed using GSEA. In vitro, HepG2 and Huh7 cells were transfected with LDHD siRNA and GFP-LDHD, the proliferation capacity of cells was examined using CCK-8, EdU, and colony formation assays; the migration and invasion of cells was detected by wound healing and transwell assays; western blotting was used to detect the levels of MMP-2, MMP-9, E-cadherin, N-cadherin and Akt phosphorylation.

RESULTS

LDHs were differentially expressed in a variety of human tumor tissues. LDHs subtypes can act as pro-oncogenes or anti-oncogenes in different types of cancer and have an impact on the prognosis of patients with tumors by influencing their clinicopathological characteristics. LDHs were differentially expressed in tumor immune subtypes and molecular subtypes. In addition, LDHs expression correlated with immune checkpoint genes, tumor mutational load, and microsatellite instability. LDHD was identified to play an important role in the prognosis of HCC patients, according to a comprehensive analysis of LDHs in pan-cancer. In HepG2 and Huh7 cells, knockdown of LDHD promoted cell proliferation, migration, and invasion, promoted the protein expression levels of MMP-2, MMP-9, N-cadherin, and Akt phosphorylation, but inhibited the protein expression level of E-cadherin. In addition, LDHD overexpression showed the opposite changes.

CONCLUSION

LDHs subtypes can be used as potential prognostic markers for certain cancers. Prognostic and immunotherapeutic analysis indicated that LDHD plays an important role in the prognosis of HCC patients. In vitro experiments revealed that LDHD can affect HCC proliferation, migration, and invasion by regulating MMPs expression and EMT via Akt signaling pathway, which provides a new perspective on the anti-cancer molecular mechanism of LDHD in HCC.

Role of monocarboxylate transporter I/lactate dehydrogenase B-mediated lactate recycling in tamoxifen-resistant breast cancer cells

Although tamoxifen (TAM) is widely used in patients with estrogen receptor-positive breast cancer, the development of tamoxifen resistance is common. The previous finding suggests that the development of tamoxifen resistance is driven by epiregulin or hypoxia-inducible factor-1α-dependent glycolysis activation. Nonetheless, the mechanisms responsible for cancer cell survival and growth in a lactic acid-rich environment remain elusive. We found that the growth and survival of tamoxifen-resistant MCF-7 cells (TAMR-MCF-7) depend on glycolysis rather than oxidative phosphorylation. The levels of the glycolytic enzymes were higher in TAMR-MCF-7 cells than in parental MCF-7 cells, whereas the mitochondrial number and complex I level were decreased. Importantly, TAMR-MCF-7 cells were more resistant to low glucose and high lactate growth conditions. Isotope tracing analysis using 13C-lactate confirmed that lactate conversion to pyruvate was enhanced in TAMR-MCF-7 cells. We identified monocarboxylate transporter1 (MCT1) and lactate dehydrogenase B (LDHB) as important mediators of lactate influx and its conversion to pyruvate, respectively. Consistently, AR-C155858 (MCT1 inhibitor) inhibited the proliferation, migration, spheroid formation, and in vivo tumor growth of TAMR-MCF-7 cells. Our findings suggest that TAMR-MCF-7 cells depend on glycolysis and glutaminolysis for energy and support that targeting MCT1- and LDHB-dependent lactate recycling may be a promising strategy to treat patients with TAM-resistant breast cancer.

Microrchidia 2/histone deacetylase 1 complex regulates E-cadherin gene expression and function

Although Microrchidia 2 (MORC2) is widely overexpressed in human malignancies and linked to cancer cell proliferation, metabolism, and metastasis, the mechanism of action of MORC2 in cancer cell migration and invasion is yet undeciphered. Here, we identified for the first time that MORC2, a chromatin remodeler, regulates E-cadherin expression and, subsequently regulates breast cancer cell migration and invasion. We observed a negative correlation between the expression levels of MORC2 and E-cadherin in breast cancer. Furthermore, the overexpression of MORC2 resulted in decreased expression levels of E-cadherin. In addition, co-immunoprecipitation and chromatin immunoprecipitation assays revealed that MORC2 interacts with HDAC1 and gets recruited onto the E-cadherin promoter to inhibit its transcription, thereby suppress its expression. Consequently, knockdown of HDAC1 in MORC2-overexpressing cells led to reduced cancer cell migration and invasion. Interestingly, we noticed that MORC2-regulated glucose metabolism via c-Myc, and LDHA, also modulates the expression of E-cadherin. Collectively, these results demonstrate for the first time a mechanistic role for MORC2 as an upstream regulator of E-cadherin expression and its associated functions in breast cancer.

LDHA-regulated tumor-macrophage symbiosis promotes glioblastoma progression

Abundant macrophage infiltration and altered tumor metabolism are two key hallmarks of glioblastoma. By screening a cluster of metabolic small-molecule compounds, we show that inhibiting glioblastoma cell glycolysis impairs macrophage migration and lactate dehydrogenase (LDH) inhibitor stiripentol (an FDA-approved anti-seizure drug for Dravet Syndrome) emerges as the top hit. Combined profiling and functional studies demonstrate that LDHA-directed ERK pathway activates YAP1/STAT3 transcriptional co-activators in glioblastoma cells to upregulate CCL2 and CCL7, which recruit macrophages into the tumor microenvironment. Reciprocally, infiltrating macrophages produce LDHA-containing extracellular vesicles to promote glioblastoma cell glycolysis, proliferation, and survival. Genetic and pharmacological inhibition of LDHA-mediated tumor-macrophage symbiosis markedly suppresses tumor progression and macrophage infiltration in glioblastoma mouse models. Analysis of tumor and plasma samples of glioblastoma patients confirms that LDHA and its downstream signals are potential biomarkers correlating positively with macrophage density. Thus, LDHA-mediated tumor-macrophage symbiosis provides therapeutic targets for glioblastoma.

Integrative analysis of lactylation-related genes and establishment of a novel prognostic signature for hepatocellular carcinoma

BACKGROUND

Lactylation has been found to involve in regulating many types of biological process in cancers. However, research on lactylation-related genes in predicting the prognosis of hepatocellular carcinoma (HCC) remains limited.

METHODS

The differential expression of lactylation-related genes (EP300 and HDAC1-3) in pan-cancer were examined in public databases. HCC patient tissues were obtained for mRNA expression and lactylation level detection by RT-qPCR and western blotting. Transwell migration assay, CCK-8 assay, EDU staining assay and RNA-seq were performed to verify the potential function and mechanisms in HCC cell lines after lactylation inhibitor apicidin treatment. lmmuCellAI, quantiSeq, xCell, TIMER and CIBERSOR were used to analyze the correlation between transcription levels of lactylation-related genes and immune cell infiltration in HCC. Risk model of lactylation-related genes was constructed by LASSO regression analysis, and prediction effect of the model was evaluated.

RESULT

The mRNA levels of lactylation-related genes and lactylation levels were higher in HCC tissues than normal samples. The lactylation levels, cell migration, and proliferation ability of HCC cell lines were suppressed after apicidin treatment. The dysregulation of EP300 and HDAC1-3 was associated with proportion of immune cell infiltration, especially B cell. Upregulation of HDAC1 and HDAC2 was closely associated with poorer prognosis. Finally, a novel risk model, based on HDAC1 and HDAC2, was developed for prognosis prediction in HCC.

CONCLUSION

HDAC1 and HDAC2 are expected to become new biomarkers for HCC. Risk scoring model based on HDAC1 and HDAC2 can be used to predict the prognosis of HCC patients.

Development and validation of a nomogram to predict lung metastasis in patients with testicular germ cell tumors

Background

Lung metastatic tumor (LM) is one of testicular germ cell tumors' most common metastatic sites. Our study aimed to develop a nomogram for predicting the risk of LM among patients with testicular germ cell tumors (TGCTs).

Methods

Clinicopathological information of 4078 patients with TGCT between 2010 and 2015 was obtained from SEER. Univariate and multivariate logistic regression analyses were performed to identify risk factors for LM, and a nomogram was developed based on these factors. Calibration curves, area under the receiver operating curve (AUC), and decision curve analysis (DCA) were used to evaluate the accuracy and discrimination of the model.

Results

Study participants included 4078 people with TGCTs, including 305 people with LM. They were randomly divided into two groups (training cohort = 2854 and validation cohort = 1224) at a ratio of 7:3. The following variables were incorporated in the nomogram: marital status, tumor histological type, T stage, brain metastasis, liver metastasis, lactate dehydrogenase (LDH), and chemotherapy. Besides, the AUC of it was 0.922 in the training cohort, while was 0.930 in the validation cohort. Training and validation cohort calibrations showed that the nomogram had excellent predictive abilities. DCA suggested it was more clinically relevant than the traditional TN staging.

Conclusion

We have established a nomogram to predict the risk of LM in patients with TGCTs. Doctors and patients can use this nomogram to monitor and identify lung metastasis of tumors through active monitoring and follow-up.

Synthesis and hLDH Inhibitory Activity of Analogues to Natural Products with 2,8-Dioxabicyclo[3.3.1]nonane Scaffold

Human lactate dehydrogenase (hLDH) is a tetrameric enzyme present in almost all tissues. Among its five different isoforms, hLDHA and hLDHB are the predominant ones. In the last few years, hLDHA has emerged as a therapeutic target for the treatment of several kinds of disorders, including cancer and primary hyperoxaluria. hLDHA inhibition has been clinically validated as a safe therapeutic method and clinical trials using biotechnological approaches are currently being evaluated. Despite the well-known advantages of pharmacological treatments based on small-molecule drugs, few compounds are currently in preclinical stage. We have recently reported the detection of some 2,8-dioxabicyclo[3.3.1]nonane core derivatives as new hLDHA inhibitors. Here, we extended our work synthesizing a large number of derivatives (42-70) by reaction between flavylium salts (27-35) and several nucleophiles (36-41). Nine 2,8-dioxabicyclo[3.3.1]nonane derivatives showed IC₅₀ values lower than 10 µM against hLDHA and better activity than our previously reported compound 2. In order to know the selectivity of the synthesized compounds against hLDHA, their hLDHB inhibitory activities were also measured. In particular, compounds 58, 62a, 65b, and 68a have shown the lowest IC₅₀ values against hLDHA (3.6-12.0 µM) and the highest selectivity rate (>25). Structure-activity relationships have been deduced. Kinetic studies using a Lineweaver-Burk double-reciprocal plot have indicated that both enantiomers of 68a and 68b behave as noncompetitive inhibitors on hLDHA enzyme.

Understanding the Contribution of Lactate Metabolism in Cancer Progress: A Perspective from Isomers

Lactate mediates multiple cell-intrinsic effects in cancer metabolism in terms of development, maintenance, and metastasis and is often correlated with poor prognosis. Its functions are undertaken as an energy source for neighboring carcinoma cells and serve as a lactormone for oncogenic signaling pathways. Indeed, two isomers of lactate are produced in the Warburg effect: L-lactate and D-lactate. L-lactate is the main end-production of glycolytic fermentation which catalyzes glucose, and tiny D-lactate is fabricated through the glyoxalase system. Their production inevitably affects cancer development and therapy. Here, we systematically review the mechanisms of lactate isomers production, and highlight emerging evidence of the carcinogenic biological effects of lactate and its isomers in cancer. Accordingly, therapy that targets lactate and its metabolism is a promising approach for anticancer treatment.

Energy metabolism pathways in breast cancer progression: The reprogramming, crosstalk, and potential therapeutic targets

Breast cancer (BC) is a malignant tumor that seriously endangers health in women. BC, like other cancers, is accompanied by metabolic reprogramming. Among energy metabolism-related pathways, BC exhibits enhanced glycolysis, tricarboxylic acid (TCA) cycle, pentose phosphate pathway (PPP), glutamate metabolism, and fatty acid metabolism activities. These pathways facilitate the proliferation, growth and migration of BC cells. The progression of BC is closely related to the alterations in the activity or expression level of several metabolic enzymes, which are regulated by the intrinsic factors such as the key signaling and transcription factors. The metabolic reprogramming in the progression of BC is attributed to the aberrant expression of the signaling and transcription factors associated with the energy metabolism pathways. Understanding the metabolic mechanisms underlying the development of BC will provide a druggable potential for BC treatment and drug discovery.

NAD/NAMPT and mTOR Pathways in Melanoma: Drivers of Drug Resistance and Prospective Therapeutic Targets

Malignant melanoma represents the most fatal skin cancer due to its aggressive behavior and high metastatic potential. The introduction of BRAF/MEK inhibitors and immune-checkpoint inhibitors (ICIs) in the clinic has dramatically improved patient survival over the last decade. However, many patients either display primary (i.e., innate) or develop secondary (i.e., acquired) resistance to systemic treatments. Therapeutic resistance relies on the rewiring of multiple processes, including cancer metabolism, epigenetics, gene expression, and interactions with the tumor microenvironment that are only partially understood. Therefore, reliable biomarkers of resistance or response, capable of facilitating the choice of the best treatment option for each patient, are currently missing. Recently, activation of nicotinamide adenine dinucleotide (NAD) metabolism and, in particular, of its rate-limiting enzyme nicotinamide phosphoribosyltransferase (NAMPT) have been identified as key drivers of targeted therapy resistance and melanoma progression. Another major player in this context is the mammalian target of rapamycin (mTOR) pathway, which plays key roles in the regulation of melanoma cell anabolic functions and energy metabolism at the switch between sensitivity and resistance to targeted therapy. In this review, we summarize known resistance mechanisms to ICIs and targeted therapy, focusing on metabolic adaptation as one main mechanism of drug resistance. In particular, we highlight the roles of NAD/NAMPT and mTOR signaling axes in this context and overview data in support of their inhibition as a promising strategy to overcome treatment resistance.

Lactate metabolism in rheumatoid arthritis: Pathogenic mechanisms and therapeutic intervention with natural compounds

BACKGROUND

Rheumatoid arthritis (RA) is a common chronic and systemic autoimmune disease characterized by persistent inflammation and hyperplasia of the synovial membrane, the degradation of cartilage, and the erosion of bones in diarthrodial joints. The inflamed joints of patients with RA have been recognized to be a site of hypoxic microenvironment which results in an imbalance of lactate metabolism and the accumulation of lactate. Lactate is no longer considered solely a metabolic waste product of glycolysis, but also a combustion aid in the progression of RA from the early stages of inflammation to the late stages of bone destruction.

PURPOSE

To review the pathogenic mechanisms of lactate metabolism in RA and investigate the potential of natural compounds for treating RA linked to the regulation of imbalance in lactate metabolism.

METHODS

Research advances in our understanding of lactate metabolism in the pathogenesis of RA and novel pharmacological approaches of natural compounds by targeting lactate metabolic signaling were comprehensively reviewed and deeply discussed.

RESULTS

Lactate produced by RA synovial fibroblasts (RASFs) acts on targeted cells such as T cells, macrophages, dendritic cells and osteoclasts, and affects their differentiation, activation and function to accelerate the development of RA. Many natural compounds show therapeutic potential for RA by regulating glycolytic rate-limiting enzymes to limit lactate production, and affecting monocarboxylate transporter and acetyl-CoA carboxylase to inhibit lactate transport and conversion.

CONCLUSION

Regulation of imbalance in lactate metabolism offers novel therapeutic approaches for RA, and natural compounds capable of targeting lactate metabolic signaling constitute potential candidates for development of drugs RA.

Mechanisms of Cell Adhesion Molecules in Endocrine-Related Cancers: A Concise Outlook

Chemotherapy is a critical treatment for endocrine-related cancers; however, chemoresistance and disease recurrence remain a challenge. The interplay between cancer cells and the tumor microenvironment via cell adhesion molecules (CAMs) promotes drug resistance, known as cell adhesion-mediated drug resistance (CAM-DR). CAMs are cell surface molecules that facilitate cell-to-cell or cell-to-extracellular matrix binding. CAMs exert an adhesion effect and trigger intracellular signaling that regulates cancer cell stemness maintenance, survival, proliferation, metastasis, epithelial-mesenchymal transition, and drug resistance. To understand these mechanisms, this review focuses on the role of CD44, cadherins, selectins, and integrins in CAM-DR in endocrine-related cancers.