Energy Metabolism in Cancer: The Roles of STAT3 and STAT5 in the Regulation of Metabolism-Related Genes

Tumor-associated macrophages drive glycolysis through the IL-8/STAT3/GLUT3 signaling pathway in pancreatic cancer progression

Glycolytic metabolism is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and tumor-associated stromal cells play important roles in tumor metabolism. We previously reported that tumor-associated macrophages (TAMs) facilitate PDAC progression. However, little is known about whether TAMs are involved in regulating glycolysis in PDAC. Here, we found a positive correlation between CD68+ TAM infiltration and FDG maximal standardized uptake (FDG SUVmax) on PET-CT images of PDAC. We discovered that the glycolytic gene set was prominently enriched in the high TAM infiltration group through Gene Set Enrichment Analysis using The Cancer Genome Atlas database. Mechanistically, TAMs secreted IL-8 to promote GLUT3 expression in PDAC cells, enhancing tumor glycolysis both in vitro and in vivo, whereas this effect could be blocked by the IL-8 receptor inhibitor reparixin. Furthermore, IL-8 promoted the translocation of phosphorylated STAT3 into the nucleus to activate the GLUT3 promoter. Overall, we demonstrated that TAMs boosted PDAC cell glycolysis through the IL-8/STAT3/GLUT3 signaling pathway. Our cumulative findings suggest that the abrogation of TAM-induced tumor glycolysis by reparixin might exhibit an antitumor impact and offer a potential therapeutic target for PDAC.

ENO2 promotes anoikis resistance in anaplastic thyroid cancer by maintaining redox homeostasis

Background

Anoikis presents a significant barrier in the metastasis of cancer. As the most aggressive type of thyroid cancer, anaplastic thyroid cancer (ATC) exhibits a high risk of metastasis and is characterized by high mortality. Therefore, investigating the molecular mechanisms of anoikis resistance in ATC is important for devising therapeutic targets in clinical research.

Methods

Differentially Expressed Genes were screened in ATC cells under attached and detached culture conditions with RNA-seq. Investigate the impact of enolase 2 (ENO2) on apoptosis and spheroid formation by gain and loss of function. Changes of reactive oxygen species (ROS), glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH) were detected to assess redox balance. The transcriptional regulatory role of signal transducer and activator of transcription 1 (STAT1) on ENO2 was validated through Dual-Luciferase Reporter Gene Assay. Explore the impact of ENO2 expression on the formation of lung metastases in nude mice.

Results

We found that the glycolysis process was activated in detached ATC cells. Several genes in the glycolysis process, particularly ENO2, a member of the enolase superfamily was upregulated in ATC cells cultured in suspension. The upregulation of ENO2 enabled the maintenance of redox balance by supplying GSH and NADPH, thereby preventing cells from undergoing anoikis. In terms of mechanism, the expression of STAT1 was enhanced in anoikis resistance cells, which in turn positively regulated the expression of ENO2. In vivo, ENO2-suppressed ATC cells resulted in a significantly lower rate of lung colonization compared to control ATC cells.

Conclusions

Stable expression of ENO2 and the maintenance of redox balance played a pivotal role in facilitating anoikis resistance of ATC.

Role of STAT3 in pancreatic cancer

Pancreatic cancer remains a serious and deadly disease, impacting people globally. There remain prominent gaps in the current understanding of the disease, specifically regarding the role of the signal transducer and activator of transcription (STAT) family of proteins in pancreatic tumors. STAT proteins, particularly STAT3, play important roles in pancreatic cancer, especially pancreatic ductal adenocarcinoma (PDAC), which is the most prevalent histotype. The role of STAT3 across a continuum of molecular processes, such as PDAC tumorigenesis and progression, immune escape, drug resistance and stemness, and modulation of the tumor microenvironment (TME), are only a tip of the iceberg. In some ways, the role of STAT3 in PDAC may hold greater importance than that of oncogenic Kirsten rat sarcoma virus (KRAS). This makes STAT3 a highly attractive target for developing targeted therapies for the treatment of pancreatic cancer. In this review, the current knowledge of STAT3 in pancreatic cancer has been summarized, particularly relating to STAT3 activation in cancer cells, cells of the TME, and the state of targeting STAT3 in pre-clinical and clinical trials of PDAC.

Complex II ambiguities-FADH2 in the electron transfer system

The prevailing notion that reduced cofactors NADH and FADH2 transfer electrons from the tricarboxylic acid cycle to the mitochondrial electron transfer system creates ambiguities regarding respiratory Complex II (CII). CII is the only membrane-bound enzyme in the tricarboxylic acid cycle and is part of the electron transfer system of the mitochondrial inner membrane feeding electrons into the coenzyme Q-junction. The succinate dehydrogenase subunit SDHA of CII oxidizes succinate and reduces the covalently bound prosthetic group FAD to FADH2 in the canonical forward tricarboxylic acid cycle. However, several graphical representations of the electron transfer system depict FADH2 in the mitochondrial matrix as a substrate to be oxidized by CII. This leads to the false conclusion that FADH2 from the β-oxidation cycle in fatty acid oxidation feeds electrons into CII. In reality, dehydrogenases of fatty acid oxidation channel electrons to the Q-junction but not through CII. The ambiguities surrounding Complex II in the literature and educational resources call for quality control, to secure scientific standards in current communications of bioenergetics, and ultimately support adequate clinical applications. This review aims to raise awareness of the inherent ambiguity crisis, complementing efforts to address the well-acknowledged issues of credibility and reproducibility.

Unveiling the growing significance of metabolism in modulating immune cell function: exploring mechanisms and implications; a review

Immunometabolism has emerged as a rapidly growing field of research, holding significant promise for personalised medicine and precision immunotherapy. This review explores the intricate relationship between immune function and metabolic processes, emphasising their profound impact on various immune-related disorders. Understanding how metabolic dysregulation contributes to the pathogenesis of these disorders remains a critical research gap. Therefore, this review aims to bridge that gap by examining the key metabolic pathways involved and their specific implications in immune cell function. Key metabolic pathways, including glycolysis, mitochondrial metabolism, fatty acid metabolism, and amino acid metabolism, are discussed in the context of immune cell function. Dysregulation of these pathways can disrupt immune cell activation, differentiation, and overall function, contributing to disease pathogenesis. Understanding these metabolic alterations' molecular mechanisms is essential for developing targeted therapeutic interventions. The review also emphasises the importance of personalised medicine in immune-related disorders. The unique metabolic profiles of individuals can influence treatment outcomes, highlighting the need for tailored approaches. Integrating metabolic profiling into clinical practice can enhance treatment efficacy and improve patient outcomes. Investigating the clinical significance of immunometabolism in diverse disease contexts will facilitate the translation of research findings into clinical practice. Moreover, refining treatment strategies based on individual metabolic profiles will contribute to advancing precision immunotherapy.

Relationship between the expression of PD-L1 and 18F-FDG uptake in pancreatic ductal adenocarcinoma

BACKGROUND

PD-L1 promotes glycolysis in tumour cells. We observed a correlation between high PD-L1 expression and high 18F-FDG uptake in patients with pancreatic ductal adenocarcinoma (PDAC) in a previous study. This study aims to determine the usefulness of 18F-FDG PET/CT for evaluating the PD-L1 status in PDAC and to elucidate its rationality by integrated analyses.

METHODS

For bioinformatics analysis, WGCNA, GSEA and TIMER were applied to analyse the pathways and hub genes associated with PD-L1 and glucose uptake. 18F-FDG uptake assay was used to determine the glucose uptake rate of PDAC cells in vitro. Related genes expression were verified by RT-PCR and western blot. A retrospective analysis was performed on 47 patients with PDAC who had undergone 18F-FDG PET/CT. Maximum standardised uptake values (SUVmax) were determined. The usefulness of SUVmax for evaluating PD-L1 status was determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

Bioinformatics analysis showed that several signalling pathways are associated with both PD-L1 expression and tumour glucose uptake, among which JAK-STAT may be an important one. By in vitro experiments, the regulatory role of PD-L1 on glucose uptake was demonstrated, and its dependency on the JAK-STAT pathway was also verified by the rescue study. The SUVmax of PD-L1-positive patients was significantly higher than PD-L1-negative in tumour cells (TCs) (6.1 ± 2.3 vs. 11.1 ± 4.2; P < 0.001), and in tumour-infiltrating immune cells (TIICs) (6.4 ± 3.2 vs. 8.4 ± 3.5; P < 0.001). In a multivariate analysis, SUVmax was significantly associated with PD-L1 expression in TCs and TIICs (P < 0.001 and P = 0.018, respectively). Using SUVmax cut-off values of 8.15 and 7.75, PD-L1 status in TCs and TIICs could be predicted with accuracies of 91.5% and 74.5%, respectively.

CONCLUSION

Higher 18F-FDG uptake by PDAC is associated with elevated PD-L1 expression. JAK-STAT is an important pathway that mediates PD-L1 to promote glucose uptake in PDAC.

Immune Checkpoint Inhibitors, Small-Molecule Immunotherapies and the Emerging Role of Neutrophil Extracellular Traps in Therapeutic Strategies for Head and Neck Cancer

Immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment of many cancer types, including head and neck cancers (HNC). When checkpoint and partner proteins bind, these send an "off" signal to T cells, which prevents the immune system from destroying tumor cells. However, in HNC, and indeed many other cancers, more people do not respond and/or suffer from toxic effects than those who do respond. Hence, newer, more effective approaches are needed. The challenge to durable therapy lies in a deeper understanding of the complex interactions between immune cells, tumor cells and the tumor microenvironment. This will help develop therapies that promote lasting tumorlysis by overcoming T-cell exhaustion. Here we explore the strengths and limitations of current ICI therapy in head and neck squamous cell carcinoma (HNSCC). We also review emerging small-molecule immunotherapies and the growing promise of neutrophil extracellular traps in controlling tumor progression and metastasis.

Inhibitory Effect of Phosphorothioate Oligonucleotide Complementary to G6PD mRNA on Murine Melanoma

In terms of the incidence among all tumors, skin cancer is on top, with the most deadly among them being melanoma. The search for new therapeutic agents to combat melanoma is very relevant. In our opinion, antisense oligonucleotides (ASO) aimed at suppressing the genes responsible for their viability in cancer cells give hope for treatment, which makes it possible to eliminate cancer cells near the tumor site both before and after surgery. In this article, we describe how Skeen-11 phosphorothioate oligonucleotide significantly decreased the proliferative activity of murine melanoma cells. Injections of Skeen-11 also inhibited tumor growth in mice with inoculated melanoma. A toxicity study showed no side effects with dose adjustments. The results show that the use of ASO Skeen-11 in vivo reduced the tumor size within 7 days, reduced the number of mitoses in the tumor cells, and increased the amount of necrosis compared with the control group.

Molecular Regulation of the Response of Brain Pericytes to Hypoxia

The brain needs sufficient oxygen in order to function normally. This is achieved by a large vascular capillary network ensuring that oxygen supply meets the changing demand of the brain tissue, especially in situations of hypoxia. Brain capillaries are formed by endothelial cells and perivascular pericytes, whereby pericytes in the brain have a particularly high 1:1 ratio to endothelial cells. Pericytes not only have a key location at the blood/brain interface, they also have multiple functions, for example, they maintain blood–brain barrier integrity, play an important role in angiogenesis and have large secretory abilities. This review is specifically focused on both the cellular and the molecular responses of brain pericytes to hypoxia. We discuss the immediate early molecular responses in pericytes, highlighting four transcription factors involved in regulating the majority of transcripts that change between hypoxic and normoxic pericytes and their potential functions. Whilst many hypoxic responses are controlled by hypoxia-inducible factors (HIF), we specifically focus on the role and functional implications of the regulator of G-protein signaling 5 (RGS5) in pericytes, a hypoxia-sensing protein that is regulated independently of HIF. Finally, we describe potential molecular targets of RGS5 in pericytes. These molecular events together contribute to the pericyte response to hypoxia, regulating survival, metabolism, inflammation and induction of angiogenesis.

3D Spheroid Configurations Are Possible Indictors for Evaluating the Pathophysiology of Melanoma Cell Lines

To study the molecular mechanisms responsible for inducing the spatial proliferation of malignant melanomas (MM), three-dimension (3D) spheroids were produced from several MM cell lines including SK-mel-24, MM418, A375, WM266-4, and SM2-1, and their 3D architectures and cellular metabolisms were evaluated by phase-contrast microscopy and Seahorse bio-analyzer, respectively. Several transformed horizontal configurations were observed within most of these 3D spheroids, and the degree of their deformity was increased in the order: WM266-4, SM2-1, A375, MM418, and SK-mel-24. An increased maximal respiration and a decreased glycolytic capacity were observed within the lesser deformed two MM cell lines, WM266-4 and SM2-1, as compared with the most deformed ones. Among these MM cell lines, two distinct cell lines, WM266-4 and SK-mel-24, whose 3D appearances were the closest and farthest, respectively, from being horizontally circular-shaped, were subjected to RNA sequence analyses. Bioinformatic analyses of the differentially expressed genes (DEGs) identified KRAS and SOX2 as potential master regulatory genes for inducing these diverse 3D configurations between WM266-4 and SK-mel-24. The knockdown of both factors altered the morphological and functional characteristics of the SK-mel-24 cells, and in fact, their horizontal deformity was significantly reduced. A qPCR analysis indicated that the levels of several oncogenic signaling related factors, including KRAS and SOX2, PCG1α, extracellular matrixes (ECMs), and ZO1 had fluctuated among the five MM cell lines. In addition, and quite interestingly, the dabrafenib and trametinib resistant A375 (A375DT) cells formed globe shaped 3D spheroids and showed different profiles in cellular metabolism while the mRNA expression of these molecules that were tested as above were different compared with A375 cells. These current findings suggest that 3D spheroid configuration has the potential for serving as an indicator of the pathophysiological activities associated with MM.

Melatonin protects against cadmium-induced oxidative stress via mitochondrial STAT3 signaling in human prostate stromal cells

Melatonin protects against Cadmium (Cd)-induced toxicity, a ubiquitous environmental toxicant that causes adverse health effects by increasing reactive oxygen species (ROS) production and mitochondrial dysfunction. However, the underlying mechanism remains unclear. Here, we demonstrate that Cd exposure reduces the levels of mitochondrially-localized signal transducer and activator of transcription 3 (mitoSTAT3) using human prostate stromal cells and mouse embryonic fibroblasts. Melatonin enhances mitoSTAT3 abundance following Cd exposure, which is required to attenuate ROS damage, mitochondrial dysfunction, and cell death caused by Cd exposure. Moreover, melatonin increases mitochondrial levels of GRIM-19, an electron transport chain component that mediates STAT3 import into mitochondria, which are downregulated by Cd. In vivo, melatonin reverses the reduced size of mouse prostate tissue and levels of mitoSTAT3 and GRIM-19 induced by Cd exposure. Together, these data suggest that melatonin regulates mitoSTAT3 function to prevent Cd-induced cytotoxicity and could preserve mitochondrial function during Cd-induced stress.

Atractylenolide I ameliorates cancer cachexia through inhibiting biogenesis of IL-6 and tumour-derived extracellular vesicles

BACKGROUND

Atractylenolide I (AI) is a natural sesquiterpene lactone isolated from Atractylodes macrocephala Koidz, known as Baizhu in traditional Chinese medicine. AI has been found to ameliorate cancer cachexia in clinic cancer patients and in tumour-bearing mice. Here, we checked the influence of AI on biogenesis of IL-6 and extracellular vesicles (EVs) in cancer cachexia mice and then focused on studying mechanisms of AI in inhibiting the production of tumour-derived EVs, which contribute to the ameliorating effects of AI on cancer cachexia.

METHODS

C26 tumour-bearing BALB/c mice were applied as animal model to examine the effects of AI (25 mg/kg) in attenuating cachexia symptoms, serum IL-6 and EVs levels. IL-6 and EVs secretion of C26 tumour cells treated with AI (0.31-5 μM) was further observed in vitro. The in vitro cultured C2C12 myotubes and 3T3-L1 mature adipocytes were used to check the potency of conditioned medium of C26 cells treated with AI (0.625-5 μM) in inducing muscle atrophy and lipolysis. The glycolysis potency of C26 cells under AI (0.31-5 μM) treatment was evaluated by measuring the extracellular acidification rate using Seahorse XFe96 Analyser. Levels of related signal proteins in both in vitro and in vivo experiments were examined using western blotting to study the possible mechanisms. STAT3 overexpression or knockout C26 cells were also used to confirm the effects of AI (5 μM).

RESULTS

AI ameliorated cancer cachexia symptoms (P < 0.05), improved grip strength (P < 0.05) and decreased serum EVs (P < 0.05) and IL-6 (P < 0.05) levels of C26 tumour-bearing mice. AI directly inhibited EVs biogenesis (P < 0.001) and IL-6 secretion (P < 0.01) of cultured C26 cells. The potency of C26 medium in inducing C2C12 myotube atrophy (+59.54%, P < 0.001) and 3T3-L1 adipocyte lipolysis (+20.73%, P < 0.05) was significantly attenuated when C26 cells were treated with AI. AI treatment inhibited aerobic glycolysis and the pathway of STAT3/PKM2/SNAP23 in C26 cells. Furthermore, overexpression of STAT3 partly antagonized the effects of AI in suppressing STAT3/PKM2/SNAP23 pathway, EVs secretion, glycolysis and the potency of C26 medium in inducing muscle atrophy and lipolysis, whereas knockout of STAT3 enhanced the inhibitory effect of AI on these values. The inhibition of AI on STAT3/PKM2/SNAP23 pathway was also observed in C26 tumour tissues.

CONCLUSIONS

AI ameliorates cancer cachexia by decreasing the production of IL-6 and EVs of tumour cells. The decreasing effects of AI on EVs biogenesis are based on its inhibition on STAT3/PKM2/SNAP23 pathway.

Regulation of Metabolic Plasticity in Cancer Stem Cells and Implications in Cancer Therapy

Cancer stem cells (CSCs), a subpopulation of tumor cells with self-renewal capacity, have been associated with tumor initiation, progression, and therapy resistance. While the bulk of tumor cells mainly use glycolysis for energy production, CSCs have gained attention for their ability to switch between glycolysis and oxidative phosphorylation, depending on their energy needs and stimuli from their microenvironment. This metabolic plasticity is mediated by signaling pathways that are also implicated in the regulation of CSC properties, such as the Wnt/β-catenin, Notch, and Hippo networks. Two other stemness-associated processes, autophagy and hypoxia, seem to play a role in the metabolic switching of CSCs as well. Importantly, accumulating evidence has linked the metabolic plasticity of CSCs to their increased resistance to treatment. In this review, we summarize the metabolic signatures of CSCs and the pathways that regulate them; we especially highlight research data that demonstrate the metabolic adaptability of these cells and their role in stemness and therapy resistance. As the development of drug resistance is a major challenge for successful cancer treatment, the potential of specific elimination of CSCs through targeting their metabolism is of great interest and it is particularly examined.

Influence of Long Non-Coding RNA in the Regulation of Cancer Stem Cell Signaling Pathways

Over the past two decades, cancer stem cells (CSCs) have emerged as an immensely studied and experimental topic, however a wide range of questions concerning the topic still remain unanswered; in particular, the mechanisms underlying the regulation of tumor stem cells and their characteristics. Understanding the cancer stem-cell signaling pathways may pave the way towards a better comprehension of these mechanisms. Signaling pathways such as WNT, STAT, Hedgehog, NOTCH, PI3K/AKT/mTOR, TGF-β, and NF-κB are responsible not only for modulating various features of CSCs but also their microenvironments. Recently, the prominent roles of various non-coding RNAs such as small non-coding RNAs (sncRNAs) and long non-coding RNAs (lncRNAs) in developing and enhancing the tumor phenotypes have been unfolded. This review attempts to shed light on understanding the influence of long non- coding RNAs in the modulation of various CSC-signaling pathways and its impact on the CSCs and tumor properties; highlighting the protagonistic and antagonistic roles of lncRNAs.

Carcinogenic microbiota and its role in colorectal cancer development

Colorectal cancer (CRC) is one of the most common malignancies worldwide. The main risk factors for CRC are family history of colon or rectal cancer, familial polyposis syndrome or hereditary nonpolyposis, and chronic inflammatory bowel diseases (ulcerative colitis and Crohn's disease). Recent studies show that the gastrointestinal microbiota play a significant role in colorectal carcinogenesis. In this review we present the microorganisms, whose influence on the development of CRC has been proven: Bacteroides fragilis, Clostridioides and Clostridium spp., Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Peptostreptococcus anaerobius, Streptococcus bovis group, and sulfate-reducing bacteria. Moreover, the carcinogenic mechanisms of action mediated by the above bacteria are laid out.

Keratinocyte-induced costimulation of human T cells through CD6 - but not CD2 - activates mTOR and prevents oxidative stress

In psoriasis and other inflammatory skin diseases, keratinocytes (KCs) secrete chemokines that attract T cells, which, in turn, cause epidermal hyperplasia by secreting proinflammatory cytokines. To date, it remains unclear whether skin-homing T cells, particularly memory T cells, can also be activated by direct cell contact with KCs. In this study, we demonstrated the ability of primary human KCs to activate human memory T cells directly by transmitting costimulatory signals through the CD6/CD166/CD318 axis. Interestingly, despite being negative for CD80/CD86, KCs initiate a metabolic shift within T cells. Blockade of the CD6/CD166/CD318 axis prevents mammalian target of rapamycin activation and T cell proliferation but promotes oxidative stress and aerobic glycolysis. In addition, it diminishes formation of central memory T cells. Importantly, although KC-mediated costimulation by CD2/CD58 also activates T cells, it cannot compensate for the lack of CD6 costimulation. Therefore, KCs likely differentially regulate T cell functions in the skin through two distinct costimulatory receptors: CD6 and CD2. This may at least in part explain the divergent effects observed when treating inflammatory skin diseases with antibodies to CD6 versus CD2. Moreover, our findings may provide a molecular basis for selective interference with either CD6/CD166/CD318, or CD2/CD58, or both to specifically treat different types of inflammatory skin diseases.

Prognostic signature construction of energy metabolism-related genes in pancreatic cancer

Pancreatic cancer is the 7th leading cause of cancer death worldwide, and its incidence and mortality rate have been on the rise in recent years in Western developed countries. The specificity of the disease and the lack of appropriate treatments have resulted in a 5-year overall survival rate of only 9%. In this study, we conducted a study based on the TCGA database and GEO database and analyzed using the energy metabolism gene set to establish a prognostic model with the least absolute shrinkage and selection operator to identify 7-genes prognostic signature, and the gene expression was verified by Real-time PCR. The model was validated using a risk score calculation, and the OS rates of the 7 genes were analyzed using one-way Cox regression. The prognostic relationship between vesicle-associated membrane protein 2 (VAMP2) and pancreatic cancer patients was analyzed by OS and progression-free survival, and the prognosis was found to be significantly worse in the high-expression group. A Nomogram showed that VAMP2 was an independent prognostic factor in pancreatic cancer. Gene set enrichment analysis showed that VAMP2 upregulation was enriched in pathways associated with immune response and that VAMP2 downregulation was enriched in metabolism-related pathways. The association of VAMP2 with immune cell infiltration was analyzed for the enrichment results, and VAMP2 was found to be positively associated with all 6 immune cells. The results of this study suggest that VAMP2 is an independent prognostic factor associated with energy metabolism in pancreatic cancer and may be involved in the immune response.

WZB117 enhanced the anti-tumor effect of apatinib against melanoma via blocking STAT3/PKM2 axis

Background: Melanoma is the most lethal skin malignant tumor with a short survival once stepping into the metastatic status and poses a therapeutic challenge. Apatinib (a tyrosine kinase inhibitor) is a promising antiangiogenic agent for the treatment of metastatic melanoma. However, antiangiogenic monotherapy is prone to acquired drug resistance and has a limited therapeutic effect. The persistence dependence of glycolytic metabolism in antiangiogenic therapy-resistant cells provides evidence that glycolysis inhibitors may enhance the effect of antiangiogenic therapy. So, this study aimed to investigate whether WZB117 (a specific GLUT1 inhibitor) could enhance the anti-tumor effect of apatinib against melanoma and its potential mechanisms.

Methods: We investigated the anti-tumor effects of apatinib alone or in combination with WZB117 on human melanoma cell lines (A375 and SK-MEL-28). The MTT assay determined cell viability and the half-maximal inhibitory concentration (IC50). Multiple drug effect/combination indexes (CI) analysis was conducted to assess interactions between apatinib and WZB117. Signal transducer and activator of transcription 3 (STAT3) pathway measured by western blotting and immunofluorescence staining. RNA expression analyses were performed using the reverse transcription-quantitative PCR method.

Results: Apatinib and WZB117 showed dose and time-dependent growth inhibitory effects in both melanoma cells. The IC50 of apatinib at 48 h in A375 and SK-MEL-28 cells was 62.58 and 59.61 μM, respectively, while the IC50 of WZB117 was 116.85 and 113.91 μM, respectively. The CI values of the two drugs were 0.538 and 0.544, respectively, indicating a synergistic effect of apatinib combined with WZB117. We also found that glucose consumption and lactate production were suppressed by apatinib plus WZB117 in a dose-dependent manner, paralleled by reducing glycolytic enzyme pyruvate kinase M2 (PKM2). The potential mechanism of the combination was to suppress the phosphorylation of STAT3. Knockdown of STAT3 by siRNA inhibited the expression of PKM2, while the activation of STAT3 by IL-6 increased the expression of PKM2. The effects of IL-6 were attenuated by apatinib combined with WZB117 treatment.

Conclusion: WZB117 enhanced the anti-tumor effect of apatinib against melanoma via modulating glycolysis by blocking the STAT3/PKM2 axis, which suggested the combination of apatinib with WZB117 could be a potential therapeutic candidate for melanoma.

Gankyrin modulated non-small cell lung cancer progression via glycolysis metabolism in a YAP1-dependent manner

Non-small cell lung cancer (NSCLC) is highly malignant and heterogeneous form of lung cancer and involves various oncogene alterations. Glycolysis, an important step in tumor metabolism, is closely related to cancer progression. In this study, we investigated the biological function and mechanism of action of Gankyrin in glycolysis and its association with NSCLC. Analyzed of data from The Cancer Genome Atlas as well as NSCLC specimens and adjacent tissues demonstrated that Gankyrin expression was upregulated in NSCLC tissues compared to adjacent normal tissues. Gankyrin was found to significantly aggravate cancer-related phenotypes, including cell viability, migration, invasion, and epithelial mesenchymal transition (EMT), whereas Gankyrin silencing alleviated the malignant phenotype of NSCLC cells. Our results reveal that Gankyrin exerted its function by regulating YAP1 expression and increasing its nuclear translocation. Importantly, YAP1 actuates glycolysis, which involves glucose uptake, lactic acid production, and ATP generation and thus might contribute to the tumorigenic effect of Gankyrin. Furthermore, the Gankyrin-accelerated glycolysis in NSCLC cells was reversed by YAP1 deficiency. Gankyrin knockdown reduced A549 cell tumorigenesis and EMT and decreased YAP1 expression in a subcutaneous xenograft nude mouse model. In conclusion, both Gankyrin and YAP1 play important roles in tumor metabolism, and Gankyrin-targeted inhibition may be a potential anti-cancer therapeutic strategy for NSCLC.

Investigating the potential therapeutic role of targeting STAT3 for overcoming drug resistance by regulating energy metabolism in chronic myeloid leukemia cells

Objectives

STATs are one of the initial targets of emerging anti-cancer agents due to their regulatory roles in survival, apoptosis, drug response, and cellular metabolism in CML. Aberrant STAT3 activity promotes malignancy, and acts as a metabolic switcher in cancer cell metabolism, contributing to resistance to TKI nilotinib. To investigate the possible therapeutic effects of targeting STAT3 to overcome nilotinib resistance by evaluating various cellular responses in both sensitive and nilotinib resistant CML cells and to test the hypothesis that energy metabolism modulation could be a mechanism for re-sensitization to nilotinib in resistant cells.

Materials and Methods

By using RNAi-mediated STAT3 gene silencing, cell viability and proliferation assays, apoptotic analysis, expressional regulations of STAT mRNA transcripts, STAT3 total, pTyr705, pSer727 protein expression levels, and metabolic activity as energy metabolism was determined in CML model K562 cells, in vitro.

Results

Targeting STAT3 sensitized both parental and especially nilotinib resistant cells by decreasing leukemic cell survival; inducing leukemic cell apoptosis, and decreasing STAT3 mRNA and protein expression levels. Besides, cell energy phenotype was modulated by switching energy metabolism from aerobic glycolysis to mitochondrial respiration in resistant cells. RNAi-mediated STAT3 silencing accelerated the sensitization of leukemia cells to nilotinib treatment, and STAT3-dependent energy metabolism regulation could be another underlying mechanism for regaining nilotinib response.

Conclusion

Targeting STAT3 is an efficient strategy for improving the development of novel CML therapeutics for regaining nilotinib response, and re-sensitization of resistant cells could be mediated by induced apoptosis and regulation in energy metabolism.

Metabolomics of Esophageal Squamous Cell Carcinoma Tissues: Potential Biomarkers for Diagnosis and Promising Targets for Therapy

Background

The incidence of esophageal squamous cell carcinoma in China ranks first in the world. The early diagnosis technology is underdeveloped, and the prognosis is poor, which seriously threatens the quality of life of the Chinese people. Epidemiological findings are related to factors such as diet, living habits, and age. The specific mechanism is not clear yet. Metabolomics is a kind of omics that simultaneously and quantitatively analyzes the comprehensive profile of metabolites in living systems. It has unique advantages in the study of the diagnosis and pathogenesis of tumor-related diseases, especially in the search for biomarkers. Therefore, it is desirable to perform metabolic profiling analysis of cancer tissues through metabolomics to find potential biomarkers for the diagnosis and treatment of esophageal squamous cell carcinoma.

Methods

HPLC-TOF-MS/MS technology and Illumina Hiseq Xten Sequencing was used for the analysis of 210 pairs of matched esophageal squamous cell carcinoma tissues and normal tissues in Zhenjiang City, Jiangsu Province, a high-incidence area of esophageal cancer in China. Bioinformatics analysis was also performed.

Results

Through metabolomic and transcriptomic analysis, this study found that a total of 269 differential metabolites were obtained in esophageal squamous cell carcinoma and normal tissues, and 48 differential metabolic pathways were obtained through KEGG enrichment analysis. After further screening and identification, 12 metabolites with potential biomarkers to differentiate esophageal squamous cell carcinoma from normal tissues were obtained.

Conclusions

From the metabolomic data, 4 unknown compounds were found to be abnormally expressed in esophageal squamous cell carcinoma for the first time, such as 9,10-epoxy-12,15-octadecadienoate; 3 metabolites were found in multiple abnormal expression in another tumor, but upregulation or downregulation was found for the first time in esophageal cancer, such as oleoyl glycine; at the same time, it was further confirmed that five metabolites were abnormally expressed in esophageal squamous cell carcinoma, which was similar to the results of other studies, such as PE.

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

Metabolomic analysis of endometrial cancer by high-resolution magic angle spinning NMR spectroscopy

PURPOSE

To analyze endometrial metabolite profiles between patients with endometrial cancer and controls.

METHODS

Seventeen (17) women with endometrium cancer and 18 controls were enrolled in this study. ¹H HR-MAS (High Resolution-Magic Angle Spinning) NMR (Nuclear Magnetic Resonance) spectroscopy data obtained from endometrial tissue samples of patients with endometrial cancer and control group were analyzed with bioinformatics methods.

RESULTS

Principal component analysis (PCA) and the partial least squares discriminant analysis (PLS-DA) score plots obtained with the multivariate statistical analysis of pre-processed spectral data shows a separation between the samples from patients with endometrial cancer and controls. Analysis results suggest that the levels of lactate, glucose, o-phosphoethanolamine, choline, glycerophosphocholine, phosphocholine, leucine, isoleucine, valine, glutamate, glutamine, n-acetyltyrosine, methionine, taurine, alanine, aspartate and phenylalanine are increased in patients with endometrial cancer compared to the controls.

CONCLUSION

The metabolomics signature of patients with endometrial cancer is different from that of benign endometrial tissue.

The Fibrinogen-like Domain of ANGPTL3 Facilitates Lipolysis in 3T3-L1 Cells by Activating the Intracellular Erk Pathway

Background: ANGPTL3 stimulates lipolysis in adipocytes, but the underlying molecular mechanism is yet unknown. The C-terminal fibrinogen-like domain of ANGPTL3 (ANGPTL3-Fld) activates the AKT pathway in endothelial cells. Hence, we evaluated whether ANGPTL3-Fld stimulates lipolysis in adipocytes through the MAPK kinase pathway. Materials and Methods: 3T3-L1 adipocytes were treated with isoproterenol (ISO), ANGPTL3-Fld, or both. Lipolysis was evaluated through the release of free fatty acids (FFAs) in the culture medium. The activation status of intracellular kinases was evaluated with and without the inhibition of the BRAF–ERK arm of the MAPK pathway. Results: ANGPTL3-Fld alone was not able to activate lipolysis, while the combination of ANGPTL3-Fld and ISO determined a 10-fold enrichment of the FFA concentration in the culture medium with an incremental effect (twofold) when compared with ISO alone. ANGPTL3-Fld alone inhibited hormone-sensitive lipase (HSL), whereas the treatment with ISO induced the activation of HSL. The net balance of ANGPTL3-Fld and ISO cotreatment resulted in HSL activation. The results indicate that ANGPTL3-Fld generated an intracellular activation signal involving the MAPK–ERK pathway, possibly through the PDGFRβ—PLCγ-AMPK axis. Conclusion: ANGPTL3-Fld appears to act as a facilitator of lipolysis in adipocytes, and this effect was driven by a signal mediated by a pathway that is different from the canonical β-adrenergic stimulus.

STAT3 mediated regulation of glucose metabolism in leukemia cells

Cancer cells rewire metabolic pathways as they demand more ATP and building blocks for proliferation. Glucose is the most consumed nutrient by cancer cells and metabolized to lactate even in the presence of oxygen. This phenomenon is called 'aerobic glycolysis'. Also, glucose level is found lower in tumor environment. Leukemia is characterized by abnormal proliferation of hematopoietic cells. STAT3 a transcription factor and an oncogene is upregulated in many tumor types. Despite its well-defined functions, STAT3 has also been proposed as a metabolic regulator. In this study, we aimed to determine the role STAT3 activation in glucose limitation, in leukemia cell lines. K562, NB-4 and HL-60 cells were found sensitive to glucose limitation. In low glucose conditions, total and nuclear STAT3 protein was decreased in all cells. In mitochondria, S727 phosphorylated STAT3 (mitochondrial form) was determined slightly increased in K562 and NB-4 cells. On the other side, ectopically STAT3 expressing cells had increased glucose consumption and less proliferated in low glucose medium. This data suggests that aerobic glycolysis might be upregulated upon STAT3 expression in leukemia cells, in glucose limitation. Furthermore, in this study, it was found that GLUT3 expressing cells did not reduce STAT3 expression in low glucose medium. GLUT3 was previously determined as a molecular marker for cell sensitivity to glucose limitation, therefore, it could be hypothesized as GLUT3 expressing cells might not need to alter STAT3 expression in low glucose level. Overall, our data suggest that leukemia cells rewire glucose metabolism via STAT3 expression in glucose limitation. Elucidating pathways that cause differential phosphorylation of STAT3 and its interaction with other energy regulating pathways in cellular response to glucose limitation might be beneficial to design new drug targets such as STAT3 inhibitors for leukemia treatment.

STAT3 Is the Master Regulator for the Forming of 3D Spheroids of 3T3-L1 Preadipocytes

To elucidate the currently unknown mechanisms responsible for the diverse biological aspects between two-dimensional (2D) and three-dimensional (3D) cultured 3T3-L1 preadipocytes, RNA-sequencing analyses were performed. During a 7-day culture period, 2D- and 3D-cultured 3T3-L1 cells were subjected to lipid staining by BODIPY, qPCR for adipogenesis related genes, including peroxisome proliferator-activated receptor γ (Pparγ), CCAAT/enhancer-binding protein alpha (Cebpa), Ap2 (fatty acid-binding protein 4; Fabp4), leptin, and AdipoQ (adiponectin), and RNA-sequencing analysis. Differentially expressed genes (DEGs) were detected by next-generation RNA sequencing (RNA-seq) and validated by a quantitative reverse transcription–polymerase chain reaction (qRT–PCR). Bioinformatic analyses were performed on DEGs using a Gene Ontology (GO) enrichment analysis and an Ingenuity Pathway Analysis (IPA). Significant spontaneous adipogenesis was observed in 3D 3T3-L1 spheroids, but not in 2D-cultured cells. The mRNA expression of Pparγ, Cebpa, and Ap2 among the five genes tested were significantly higher in 3D spheroids than in 2D-cultured cells, thus providing support for this conclusion. RNA analysis demonstrated that a total of 826 upregulated and 725 downregulated genes were identified as DEGs. GO enrichment analysis and IPA found 50 possible upstream regulators, and among these, 6 regulators—transforming growth factor β1 (TGFβ1), signal transducer and activator of transcription 3 (STAT3), interleukin 6 (IL6), angiotensinogen (AGT), FOS, and MYC—were, in fact, significantly upregulated. Further analyses of these regulators by causal networks of the top 14 predicted diseases and functions networks (IPA network score indicated more than 30), suggesting that STAT3 was the most critical upstream regulator. The findings presented herein suggest that STAT3 has a critical role in regulating the unique biological properties of 3D spheroids that are produced from 3T3-L1 preadipocytes.

The critical role of STAT3 in biogenesis of tumor-derived exosomes with potency of inducing cancer cachexia in vitro and in vivo

Tumor-derived exosomes are emerging mediators of cancer cachexia. Clarifying the regulation of exosome biogenesis and finding possible targets for cancer cachexia therapy are important and necessary. In the present study, systemic analysis of the roles of STAT3 in controlling exosome biogenesis of murine C26 colon tumor cells and its contribution to the development of cancer cachexia is conducted. The genetic manipulation of STAT3 expression, STAT3 knockout (KO) or overexpression (OE), significantly affected the exosome biogenesis and also the potency of C26 conditioned medium (CM) in inducing muscle atrophy and lipolysis in vitro. The genetic manipulation of STAT3 expression caused change in phosphorylation of PKM2 and glycolysis. PKM2/SNAP23 pathway was involved in regulation of exosome biogenesis by STAT3 genetic manipulation as well as by STAT3 inhibitors in C26 cells. Mice inoculated with STAT3 knockout or overexpression C26 cells exhibited ameliorated or aggravated cancer cachexia symptoms, with a positive correlation with the serum exosome and IL-6 levels. The STAT3/PKM2/SNAP23 pathway was affected in C26 tumor tissues with genetic manipulation of STAT3 expression. The capacity of exosome biogenesis of different human cancer cells also exhibited a positive correlation with the activation of STAT3/PKM2/SNAP23 pathway. The research presented here confirms that STAT3 plays a critical role in regulating biogenesis of tumor-derived exosomes which could contribute to cancer cachexia development.

The impact of HPV infection on human glycogen and lipid metabolism - a review

Reinterpretation of the Wartburg effect leads to understanding aerobic glycolysis as a process that provides considerable amount of molecular precursors for the production of lipids, nucleotides and amino acids that are necessary for continuous growth and rapid proliferation characteristic for cancer cells. Human papilloma virus (HPV) is a number one cause of cervical carcinoma with 99% of the cervical cancer patients being HPV positive. This tight link between HPV and cancer raises the question if and how HPV impact cells to reprogram their metabolism? Focusing on early phase proteins E1, E2, E5, E6 and E7 we demonstrate that HPV activates plethora of metabolic pathways and directly influences enzymes of the glycolysis pathway to promote the Warburg effect by increasing glucose uptake, activating glycolysis and pentose phosphate pathway, increasing the level of lactate dehydrogenase A synthesis and inhibiting β-oxidation. Our considerations lead to conclusion that HPV is substantially involved in metabolic cell reprogramming toward neoplastic phenotype and its metabolic activity is the fundamental reason of its oncogenicity.

STAT3 as a mediator of oncogenic cellular metabolism: Pathogenic and therapeutic implications

The oncogenic transcription factor signal transducer and activator of transcription 3 (STAT3) is activated constitutively in a wide array of human cancers. It is an appealing molecular target for novel therapy as it directly regulates expression of genes involved in cell proliferation, survival, angiogenesis, chemoresistance and immune responsiveness. In addition to these well-established oncogenic roles, STAT3 has also been found to mediate a wide array of functions in modulating cellular behavior. The transcriptional function of STAT3 is canonically regulated through tyrosine phosphorylation. However, STAT3 phosphorylated at a single serine residue can allow incorporation of this protein into the inner mitochondrial membrane to support oxidative phosphorylation (OXPHOS) and maximize the utility of glucose sources. Conflictingly, its canonical transcriptional activity suppresses OXPHOS and favors aerobic glycolysis to promote oncogenic behavior. Apart from mediating the energy metabolism and controversial effects on ATP production, STAT3 signaling modulates lipid metabolism of cancer cells. By mediating fatty acid synthesis and beta oxidation, STAT3 promotes employment of available resources and supports survival in the conditions of metabolic stress. Thus, the functions of STAT3 extend beyond regulation of oncogenic genes expression to pleiotropic effects on a spectrum of essential cellular processes. In this review, we dissect the current knowledge on activity and mechanisms of STAT3 involvement in transcriptional regulation, mitochondrial function, energy production and lipid metabolism of malignant cells, and its implications to cancer pathogenesis and therapy.

STAT3 but Not STAT5 Contributes to the Protective Effect of Electroacupuncture Against Myocardial Ischemia/Reperfusion Injury in Mice

Electroacupuncture (EA) can help reduce infarct size and injury resulting from myocardial ischemia/reperfusion (I/R); however, the underlying molecular mechanism remains unknown. We previously reported that STAT5 plays a critical role in the cardioprotective effect of remote ischemic preconditioning (RIPC). Here, we assessed the effects of electroacupuncture pretreatment (EAP) on myocardial I/R injury in the presence and/or absence of Stat5 in mice and investigated whether EAP exerts its cardioprotective effects in a STAT5-dependent manner. Adult Stat5^fl/fl and Stat5-cKO mice were exposed to EAP at Neiguan (PC6) for 7 days before the induction of I/R injury by left anterior descending (LAD) coronary artery ligation. The myocardial infarct size (IS), area at risk, and apoptotic rate of cardiomyocytes were detected. RT-qPCR and western blotting were used to measure gene and protein expression, respectively, in homogenized heart tissues. RNA-seq was used to identify candidate genes and pathways. Our results showed that EAP decreased IS and the rate of cardiomyocyte apoptosis. We further found that STAT5 was activated by EAP in Stat5^fl/fl mice but not in Stat5-cKO mice, whereas the opposite was observed for STAT3. Following EAP, the levels of the antiapoptotic proteins Bcl-xL, Bcl-2, and p-AKT were increased in the presence of Stat5, while that of interleukin 10 (IL-10) was increased in both Stat5^fl/fl and Stat5-cKO. The gene expression profile in heart tissues was different between Stat5^fl/fl and the Stat5-cKO mice with EAP. Importantly, the top 30 DEGs under EAP in the Stat5-cKO mice were enriched in the IL-6/STAT3 signaling pathway. Our results revealed for the first time that the protective effect of EAP following myocardial I/R injury was attributable to, but not dependent on, STAT5. Additionally, we found that EAP could activate STAT3 signaling in the absence of the Stat5 gene, and could also activate antiapoptotic, survival, and anti-inflammatory signaling pathways.

Visceral Obesity Promotes Lung Cancer Progression-Toward Resolution of the Obesity Paradox in Lung Cancer

INTRODUCTION

Although obesity is associated with adverse cancer outcomes in general, most retrospective clinical studies suggest a beneficial effect of obesity in NSCLC.

METHODS

Hypothesizing that this "obesity paradox" arises partly from the limitations of using body mass index (BMI) to measure obesity, we quantified adiposity using preoperative computed tomography images. This allowed the specific determination of central obesity as abdominal visceral fat area normalized to total fat area (visceral fat index [VFI]). In addition, owing to the previously reported salutary effect of metformin on high-BMI patients with lung cancer, metformin users were excluded. We then explored associations between visceral obesity and outcomes after surgical resection of stage I and II NSCLC. We also explored potential immunologic underpinnings of such association using complimentary analyses of tumor gene expression data from NSCLC tumors and the tumor transcriptome and immune microenvironment in an immunocompetent model of lung cancer with diet-induced obesity.

RESULTS

We found that in 513 patients with stage I and II NSCLC undergoing lobectomy, a high VFI is associated with decreased recurrence-free and overall survival. VFI was also inversely related to an inflammatory transcriptomic signature in NSCLC tumors, consistent with observations made in immunocompetent murine models wherein diet-induced obesity promoted cancer progression while exacerbating elements of immune suppression in the tumor niche.

CONCLUSIONS

In all, this study uses multiple lines of evidence to reveal the adverse effects of visceral obesity in patients with NSCLC, which align with those found in animal models. Thus, the obesity paradox may, at least in part, be secondary to the use of BMI as a measure of obesity and the confounding effects of metformin use.

The crosstalk between HIFs and mitochondrial dysfunctions in cancer development

Mitochondria are essential cellular organelles that are involved in regulating cellular energy, metabolism, survival, and proliferation. To some extent, cancer is a genetic and metabolic disease that is closely associated with mitochondrial dysfunction. Hypoxia-inducible factors (HIFs), which are major molecules that respond to hypoxia, play important roles in cancer development by participating in multiple processes, such as metabolism, proliferation, and angiogenesis. The Warburg phenomenon reflects a pseudo-hypoxic state that activates HIF-1α. In addition, a product of the Warburg effect, lactate, also induces HIF-1α. However, Warburg proposed that aerobic glycolysis occurs due to a defect in mitochondria. Moreover, both HIFs and mitochondrial dysfunction can lead to complex reprogramming of energy metabolism, including reduced mitochondrial oxidative metabolism, increased glucose uptake, and enhanced anaerobic glycolysis. Thus, there may be a connection between HIFs and mitochondrial dysfunction. In this review, we systematically discuss the crosstalk between HIFs and mitochondrial dysfunctions in cancer development. Above all, the stability and activity of HIFs are closely influenced by mitochondrial dysfunction related to tricarboxylic acid cycle, electron transport chain components, mitochondrial respiration, and mitochondrial-related proteins. Furthermore, activation of HIFs can lead to mitochondrial dysfunction by affecting multiple mitochondrial functions, including mitochondrial oxidative capacity, biogenesis, apoptosis, fission, and autophagy. In general, the regulation of tumorigenesis and development by HIFs and mitochondrial dysfunction are part of an extensive and cooperative network.

Toll-Like Receptor 7 Mediates Inflammation Resolution and Inhibition of Angiogenesis in Non-Small Cell Lung Cancer

Simple Summary

The progression of cancer is strictly linked to the formation of new blood vessels responsible for nutrition supply of the tumor. We identified TLR7 as an inhibitor of lung cancer vascularization. TLR7 is part of a large family of immune receptors that function as “sensors” of pathogen- and damage-derived signals. We found that TLR7 exerts antitumor functions in non-small cell lung cancer by inducing the production of specific molecules with inhibitory properties against new blood vessel formation. These molecules are known as specialized pro-resolving mediators (SPMs) and are derived from ω-3 and ω-6 fatty acids. We believe that the results obtained suggest novel potential targets and strategies to treat lung cancer.

Abstract

Pattern recognition receptors (PRR) promote inflammation but also its resolution. We demonstrated that a specific PRR—formyl peptide receptor 1 (FPR1)—sustains an inflammation resolution response with anti-angiogenic and antitumor potential in gastric cancer. Since toll-like receptor 7 (TLR7) is crucial in the physiologic resolution of airway inflammation, we asked whether it could be responsible for pro-resolving and anti-angiogenic responses in non-small cell lung cancer (NSCLC). TLR7 correlated directly with pro-resolving and inversely with angiogenic mediators in NSCLC patients, as revealed by a publicly available RNAseq analysis. In NSCLC cells, depletion of TLR7 caused an upregulation of angiogenic mediators and a stronger vasculogenic response of endothelial cells compared to controls, assessed by qPCR, ELISA, protein array, and endothelial cell responses. TLR7 activation induced the opposite effects. TLR7 silencing reduced, while its activation increased, the pro-resolving potential of NSCLC cells, evaluated by qPCR, flow cytometry, and EIA. The increased angiogenic potential of TLR7-silenced NSCLC cells is due to the lack of pro-resolving mediators. MAPK and STAT3 signaling are responsible for these activities, as demonstrated through Western blotting and inhibitors. Our data indicate that TLR7 sustains a pro-resolving signaling in lung cancer that inhibits angiogenesis. This opens new possibilities to be exploited for cancer treatment.

The pleiotropic role of transcription factor STAT3 in oncogenesis and its targeting through natural products for cancer prevention and therapy

Signal transducer and activator of transcription 3 (STAT3) is one of the crucial transcription factors, responsible for regulating cellular proliferation, cellular differentiation, migration, programmed cell death, inflammatory response, angiogenesis, and immune activation. In this review, we have discussed the classical regulation of STAT3 via diverse growth factors, cytokines, G-protein-coupled receptors, as well as toll-like receptors. We have also highlighted the potential role of noncoding RNAs in regulating STAT3 signaling. However, the deregulation of STAT3 signaling has been found to be associated with the initiation and progression of both solid and hematological malignancies. Additionally, hyperactivation of STAT3 signaling can maintain the cancer stem cell phenotype by modulating the tumor microenvironment, cellular metabolism, and immune responses to favor drug resistance and metastasis. Finally, we have also discussed several plausible ways to target oncogenic STAT3 signaling using various small molecules derived from natural products.

Metformin: Metabolic Rewiring Faces Tumor Heterogeneity

Tumor heterogeneity impinges on all the aspects of tumor history, from onset to metastasis and relapse. It is growingly recognized as a propelling force for tumor adaptation to environmental and micro-environmental cues. Metabolic heterogeneity perfectly falls into this process. It strongly contributes to the metabolic plasticity which characterizes cancer cell subpopulations—capable of adaptive switching under stress conditions, between aerobic glycolysis and oxidative phosphorylation—in both a convergent and divergent modality. The mitochondria appear at center-stage in this adaptive process and thus, targeting mitochondria in cancer may prove of therapeutic value. Metformin is the oldest and most used anti-diabetic medication and its relationship with cancer has witnessed rises and falls in the last 30 years. We believe it is useful to revisit the main mechanisms of action of metformin in light of the emerging views on tumor heterogeneity. We first analyze the most consolidated view of its mitochondrial mechanism of action and then we frame the latter in the context of tumor adaptive strategies, cancer stem cell selection, metabolic zonation of tumors and the tumor microenvironment. This may provide a more critical point of view and, to some extent, may help to shed light on some of the controversial evidence for metformin’s anticancer action.

Long Noncoding RNA LINC00551 Suppresses Glycolysis and Tumor Progression by Regulating c-Myc-Mediated PKM2 Expression in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is a leading cause of mortality associated with cancer globally. Thus, it is essential to elucidate its tumorigenesis and prognosis. Accumulating evidence shows that long noncoding RNAs (lncRNAs) play important roles in the occurrence and progression of tumors by regulating their glucose metabolism.

Methods

Bioinformatics analysis was performed to explore the expression of LINC00551 in LUAD. The level of LINC00551 in LUAD cells and tissues was detected by RT-qPCR. CCK-8, colony formation, EDU and transwell assays were conducted to evaluate the cell growth and migration of LUAD cells (A549 and PC9). High throughput sequencing was used to discover the downstream genes of LINC00551. The metabolic function of LUAD cells was identified by glucose uptake and lactate production assays. Furthermore, tumor xenografts were established to investigate the effects of LINC00551 on tumor growth in vivo.

Results

Herein, we found that LINC00551 was low-expressed in LUAD, and its level correlated with clinical prognosis. Ectopic expression of LINC00551 inhibited the proliferation and migration of LUAD cells (A549 and PC9). High throughput sequencing and gene enrichment analysis revealed that LINC0551 may be involved in metabolic pathway. Glucose uptake and lactate production assays suggested that LINC00551 suppressed glycolysis of LUAD cells. Mechanistically, our work revealed that LINC00551 inhibited glycolysis in LUAD cells by impairing c-Myc-mediated transcription of an important glycolysis-related enzyme PKM2.

Conclusion

In summary, our study identifies LINC00551 as a tumor suppressor in LUAD and implicates the LINC00551/c-Myc/PKM2 axis in the glycolytic remodeling of LUAD.

Expression of YAP1 and pSTAT3-S727 and their prognostic value in glioma

AIMS

A growing research demonstrated that YAP1 played important roles in gliomagenesis. We explored the expression of YAP1 and STAT3, the relationship between them and the effect of YAP1, STAT3 on prognosis in glioma.

METHODS

Expression of YAP1, p-YAP1, STAT3, pSTAT3-S727 and pSTAT3-Y705 in 141 cases of low-grade gliomas (LGG) and 74 cases of high-grade gliomas (HGG) of surgical specimens were measured by immunohistochemistry. Pearson's X² test was used to determine the correlation between immunohistochemical expressions and clinicopathological parameters. Pearson's or Spearman correlation test was used to determine the association between these proteins expression. Survival analysis was used to investigate the effect of these proteins on prognosis.

RESULTS

High expressions of YAP1, STAT3, pSTAT3-S727 and pSTAT3-Y705 were found in HGG compared with LGG (p=0.000). High expressions of YAP1, STAT3, pSTAT3-S727 and pSTAT3-Y705 were found in 63.5%, 59.5%, 66.2% and 31.1% cases of HGG, respectively. YAP1 expression was associated to tumour location, Ki-67 and P53, STAT3 expression was related with Ki-67 and P53, and the expression of pSTAT3-S727 was associated with Ki-67. There was a significantly positive correlation between YAP1 and pSTAT3-S727 (p<0.0001; r=0.5663). Survival analysis revealed that patients with YAP1 and pSTAT3-S727 coexpression had worse overall survival (OS) and progression-free survival (PFS) (p<0.0001). Tumour grade, age, Ki-67 and YAP1 expression were independent prognostic factors for OS. In LGG group, both YAP1 and pSTAT3-S727 expressions were negative correlation with IDH1 mutation, YAP1 and pSTAT3-S727 coexpression showed worse OS and PFS of glioma patients.

CONCLUSION

Our research showed that YAP1 and STAT3 were significantly activated in HGG compared with LGG. YAP1 significantly correlated with pSTAT3-S727 in glioma, YAP1 and pSTAT3-S727 coexpression may serve as a reliable prognostic biomarker and therapeutic target for glioma.

Perspectives Regarding the Intersections between STAT3 and Oxidative Metabolism in Cancer

Signal transducer and activator of transcription 3 (STAT3) functions as a major molecular switch that plays an important role in the communication between cytokines and kinases. In this role, it regulates the transcription of genes involved in various biochemical processes, such as proliferation, migration, and metabolism of cancer cells. STAT3 undergoes diverse post-translational modifications, such as the oxidation of cysteine by oxidative stress, the acetylation of lysine, or the phosphorylation of serine/threonine. In particular, the redox modulation of critical cysteine residues present in the DNA-binding domain of STAT3 inhibits its DNA-binding activity, resulting in the inactivation of STAT3-mediated gene expression. Accumulating evidence supports that STAT3 is a key protein that acts as a mediator of metabolism and mitochondrial activity. In this review, we focus on the post-translational modifications of STAT3 by oxidative stress and how the modification of STAT3 regulates cell metabolism, particularly in the metabolic pathways in cancer cells.

The cross-talk between DDR1 and STAT3 promotes the development of hepatocellular carcinoma

Objective: To investigate the function of discoidin domain receptor 1 (DDR1) in hepatocellular carcinoma (HCC) and to further clarify the underlying mechanism.

Results: DDR1 was significantly increased in HCC tissues and cells, which was related to clinical staging and prognosis of HCC. Upregulation of DDR1 promoted EMT and glutamine metabolism in HCC cells, while loss of DDR1 showed the opposite effects. STAT3 bound with the promoter of DDR1, and facilitated the phosphorylation of STAT3. In turn, activation of STAT3 increased the expression of DDR1. Silencing of STAT3 removed the promoting effect of DDR1 on proliferation, migration and invasion of HCC cells. The in vivo tumor growth assay showed that the cross-talk between DDR1 and STAT3 promoted HCC tumorigenesis.

Conclusions: Our research revealed the positive feedback of DDR1 and STAT3 promoted EMT and glutamine metabolism in HCC, which provided some experimental basis for clinical treatment or prevention of HCC.

Materials and methods: The mRNA expression of DDR1 was detected by qRT-PCR. CCK8 assay, wound healing assay and transwell assay were used to detect the DDR1/ STAT3 function on proliferation, migration and invasion in HCC cells. Western blot was used to calculate protein level of DDR1, STAT3, epithelial-mesenchymal transition (EMT) related proteins.

Loss of miR-145-5p Causes Ceruloplasmin Interference with PHD-Iron Axis and HIF-2α Stabilization in Lung Adenocarcinoma-Mediated Angiogenesis

For decades, lung cancer has been the leading cause of cancer-related death worldwide. Hypoxia-inducible factors (HIFs) play critical roles in mediating lung cancer development and metastasis. The present study aims to clarify how HIF’s over-activation affects lung cancer angiogenesis not only in a normoxic condition, but also a hypoxic niche. Our study shows that human lung cancer exhibits elevated levels of ceruloplasmin (CP), which has a negative impact on the prognosis of patients. CP affects the cellular Fe²⁺ level, which inactivates prolyl hydroxylase (PHD) 1 and 2, resulting in HIF-2α enhancement. Increased HIF-2α leads to vascular endothelial growth factor-A (VEGF-A) secretion and angiogenesis. The expression of CP is under the epigenetic control of miR-145-5p. Restoration of miR-145-5p by miRNA mimics transfection decreases CP expression, increases Fe²⁺ and PHD1/2 levels and HIF hydroxylation while reduced HIF-2α levels resulting in the inhibition of tumor angiogenesis. In contrast, inhibition of miR-145-5p by miRNA inhibitors increases the expression of CP and VEGF-A in lung cancer cells. Significantly, miR-145-5p expression is lost in the tumor samples of lung cancer patients, and low miR-145-5p expression is strongly correlated with a shorter overall survival time. In conclusion, the current study reveals the clinical importance and prognostic value of miR-145-5p and CP. It identifies a unique mechanism of HIF-2α over-activation, which is mediated by iron imbalance of the iron-PHD coupling that modulates tumor angiogenesis.

Metabolomics in endometrial cancer diagnosis: A systematic review

INTRODUCTION

Endometrial cancer (EC) is the most common gynecological malignancy in the developed world. The prognosis of EC strongly depends on tumor stage, hence the importance of improving diagnosis. Metabolomics has recently appeared as a promising test for a non-invasive diagnosis of several diseases. Nevertheless, no metabolic marker has been approved for use in the routine practice. We aimed to provide an overview of metabolomics findings in the diagnosis of EC.

MATERIAL AND METHODS

A systematic review was performed by searching eight electronic databases from their inception to October 2019 for studies assessing metabolomics in EC diagnosis. Extracted data included characteristics of patients and EC, serum concentration of metabolites in women with and without EC and its association with EC diagnosis, tumor behavior and pathological characteristics.

RESULTS

Six studies with 732 women (356 cases and 376 controls) were included. Several metabolites were found able to predict the presence of EC, tumor behavior (progression and recurrence) and pathological characteristics (histotype, myometrial invasion and lymph vascular space invasion).

CONCLUSIONS

Metabolomics might be suitable for a non-invasive diagnosis and screening of EC, offering the possibility to predict tumor behavior and pathological characteristics. Further studies are necessary to validate these results.

Identification of an energy metabolism‑related gene signature in ovarian cancer prognosis

Changes in energy metabolism may be potential biomarkers and therapeutic targets for cancer as they frequently occur within cancer cells. However, basic cancer research has failed to reach a consistent conclusion on the function(s) of mitochondria in energy metabolism. The significance of energy metabolism in the prognosis of ovarian cancer remains unclear; thus, there remains an urgent need to systematically analyze the characteristics and clinical value of energy metabolism in ovarian cancer. Based on gene expression patterns, the present study aimed to analyze energy metabolism-associated characteristics to evaluate the prognosis of patients with ovarian cancer. A total of 39 energy metabolism-related genes significantly associated with prognosis were obtained, and three molecular subtypes were identified by nonnegative matrix factorization clustering, among which the C1 subtype was associated with poor clinical outcomes of ovarian cancer. The immune response was enhanced in the tumor microenvironment. A total of 888 differentially expressed genes were identified in C1 compared with the other subtypes, and the results of the pathway enrichment analysis demonstrated that they were enriched in the ‘PI3K-Akt signaling pathway’, ‘cAMP signaling pathway’, ‘ECM-receptor interaction’ and other pathways associated with the development and progression of tumors. Finally, eight characteristic genes (tolloid-like 1 gene, type XVI collagen, prostaglandin F2α, cartilage intermediate layer protein 2, kinesin family member 26b, interferon inducible protein 27, growth arrest-specific gene 1 and chemokine receptor 7) were obtained through LASSO feature selection; and a number of them have been demonstrated to be associated with ovarian cancer progression. In addition, Cox regression analysis was performed to establish an 8-gene signature, which was determined to be an independent prognostic factor for patients with ovarian cancer and could stratify sample risk in the training, test and external validation datasets (P<0.01; AUC >0.8). Gene Set Enrichment Analysis results revealed that the 8-gene signature was involved in important biological processes and pathways of ovarian cancer. In conclusion, the present study established an 8-gene signature associated with metabolic genes, which may provide new insights into the effects of energy metabolism on ovarian cancer. The 8-gene signature may serve as an independent prognostic factor for ovarian cancer patients.

Rac1 Signaling: From Intestinal Homeostasis to Colorectal Cancer Metastasis

The small GTPase Rac1 has been implicated in a variety of dynamic cell biological processes, including cell proliferation, cell survival, cell-cell contacts, epithelial mesenchymal transition (EMT), cell motility, and invasiveness. These processes are orchestrated through the fine tuning of Rac1 activity by upstream cell surface receptors and effectors that regulate the cycling Rac1-GDP (off state)/Rac1-GTP (on state), but also through the tuning of Rac1 accumulation, activity, and subcellular localization by post translational modifications or recruitment into molecular scaffolds. Another level of regulation involves Rac1 transcripts stability and splicing. Downstream, Rac1 initiates a series of signaling networks, including regulatory complex of actin cytoskeleton remodeling, activation of protein kinases (PAKs, MAPKs) and transcription factors (NFkB, Wnt/β-catenin/TCF, STAT3, Snail), production of reactive oxygen species (NADPH oxidase holoenzymes, mitochondrial ROS). Thus, this GTPase, its regulators, and effector systems might be involved at different steps of the neoplastic progression from dysplasia to the metastatic cascade. After briefly placing Rac1 and its effector systems in the more general context of intestinal homeostasis and in wound healing after intestinal injury, the present review mainly focuses on the several levels of Rac1 signaling pathway dysregulation in colorectal carcinogenesis, their biological significance, and their clinical impact.