2-DG-Regulated RIP and c-FLIP Effect on Liver Cancer Cell Apoptosis Induced by TRAIL

Metabolic reprogramming in the pathogenesis and progression of nasopharyngeal carcinoma: molecular mechanisms and therapeutic implications

Nasopharyngeal carcinoma (NPC) is a unique head and neck cancer with a complex etiology involving genetic predispositions, environmental factors, and Epstein-Barr virus (EBV) infection. Despite progress in radiotherapy and chemotherapy, the prognosis for advanced NPC is still unfavorable, prompting the need for innovative therapeutic approaches. Metabolic reprogramming plays a crucial role in the development and progression of NPC, marked by substantial changes in glycolysis, lipid, and amino acid metabolism. These alterations aid tumor cell proliferation, survival under stress, and immune evasion, with features such as enhanced aerobic glycolysis (Warburg effect) and shifts in lipid and amino acid pathways. Oncogenic drivers like MYC, RAS, EGFR, and the loss of tumor suppressors such as TP53 and PTEN, along with key signaling pathways including mTOR, AMPK, and HIF-1α, orchestrate these metabolic changes. This review discusses the molecular mechanisms of metabolic reprogramming in NPC and outlines potential therapeutic targets within these pathways. Advances in metabolic imaging and biomarker discovery are also enhancing the precision of diagnostics and treatment monitoring, fostering personalized medicine in NPC treatment. This manuscript aims to provide a detailed overview of the current research and its implications for improving NPC management and patient outcomes through targeted metabolic therapies.

Anti-Glycolytic Drugs in the Treatment of Hepatocellular Carcinoma: Systemic and Locoregional Options

Hepatocellular cancer (HCC) is the most common primary liver cancer and the third leading cause of cancer-related death. Locoregional therapies, including transarterial embolization (TAE: bland embolization), chemoembolization (TACE), and radioembolization, have demonstrated survival benefits when treating patients with unresectable HCC. TAE and TACE occlude the tumor's arterial supply, causing hypoxia and nutritional deprivation and ultimately resulting in tumor necrosis. Embolization blocks the aerobic metabolic pathway. However, tumors, including HCC, use the "Warburg effect" and survive hypoxia from embolization. An adaptation to hypoxia through the Warburg effect, which was first described in 1956, is when the cancer cells switch to glycolysis even in the presence of oxygen. Hence, this is also known as aerobic glycolysis. In this article, the adaptation mechanisms of HCC, including glycolysis, are discussed, and anti-glycolytic treatments, including systemic and locoregional options that have been previously reported or have the potential to be utilized in the treatment of HCC, are reviewed.

2-Deoxy-D-glucose simultaneously targets glycolysis and Wnt/β-catenin signaling to inhibit cervical cancer progression

Cervical cancer is one of the most common female malignant tumors, with typical cancer metabolism characteristics of increased glycolysis flux and lactate accumulation. 2-Deoxy-D-glucose (2-DG) is a glycolysis inhibitor that acts on hexokinase, the first rate-limiting enzyme in the glycolysis pathway. In this research, we demonstrated that 2-DG effectively reduced glycolysis and impaired mitochondrial function in cervical cancer cell lines HeLa and SiHa. Cell function experiments revealed that 2-DG significantly inhibited cell growth, migration, and invasion, and induced G0/G1 phase arrest at non-cytotoxic concentrations. In addition, we found that 2-DG down-regulated Wingless-type (Wnt)/β-catenin signaling. Mechanistically, 2-DG accelerated the degradation of β-catenin protein, which resulted in the decrease of β-catenin expression in both nucleus and cytoplasm. The Wnt agonist lithium chloride and β-catenin overexpression vector could partially reverse the inhibition of malignant phenotype by 2-DG. These data suggested that 2-DG exerted its anti-cancer effects on cervical cancer by co-targeting glycolysis and Wnt/β-catenin signaling. As expected, the combination of 2-DG and Wnt inhibitor synergistically inhibited cell growth. It is noteworthy that, down-regulation of Wnt/β-catenin signaling also inhibited glycolysis, indicating a similar positive feedback regulation between glycolysis and Wnt/β-catenin signaling. In conclusion, we investigated the molecular mechanism by which 2-DG inhibits the progression of cervical cancer in vitro, elucidated the interregulation between glycolysis and Wnt/β-catenin signaling, and preliminarily explored the effect of combined targeting of glycolysis and Wnt/β-catenin signaling on cell proliferation, which provides more possibilities for the formulation of subsequent clinical treatment strategies.

Characterization of metabolic landscape in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide, accounting for approximately 75%-85% of primary liver cancers. Metabolic alterations have been labeled as an emerging hallmark of tumors. Specially, the last decades have registered a significant improvement in our understanding of the role of metabolism in driving the carcinogenesis and progression of HCC. In this paper, we provide a review of recent studies that investigated the metabolic traits of HCC with a specific focus on three common metabolic alterations involving glycolysis, lipid metabolism, and glutamine addiction which have been gaining much attention in the field of HCC. Next, we describe some representative diagnostic markers or tools, and promising treatment agents that are proposed on the basis of the aforementioned metabolic alterations for HCC. Finally, we present some challenges and directions that may promisingly speed up the process of developing objective diagnostic markers and therapeutic options underlying HCC. Specifically, we recommend future investigations to carefully take into account the influence of heterogeneity, control for study-specific confounds, and invite the validation of existing biomarkers.

Bone mesenchymal stem cells derived extracellular vesicles promote TRAIL-related apoptosis of hepatocellular carcinoma cells via the delivery of microRNA-20a-3p

OBJECTIVE

Bone mesenchymal stem cells (BMSCs) have been widely researched in cancer treatment, including hepatocellular carcinoma (HCC). This study intended to discuss the mechanism of miR-20a-3p in BMSCs-extracellular vesicles (EVs) in HCC apoptosis.

METHODS

BMSCs were isolated and identified. EVs derived from BMSCs were extracted and identified. After overexpressing or inhibiting miR-20a-3p expression in BMSCs, EVs were extracted and acted on HCC cells and transplanted tumors. HCC cell apoptosis in the treatment of BMSCs-conditioned medium, BMSCs-EVs and/or miR-20a-3p mimic/inhibitor was evaluated, with the detection of levels of TRAIL and TRAIL-related proteins. A functional rescue experiment about c-FLIP was carried out in HCC cells. The target binding relationship between miR-20a-3p and c-FLIP was detected. The subcutaneous tumorigenesis model of mice was established and injected with BMSCs-EVs to estimate the effect of BMSCs-EVs-miR-20a-3p on HCC growth.

RESULTS

EVs isolated from BMSCs conditioned medium promoted the apoptosis of HCC cells. After BMSCs-EVs treatment, TRAIL levels, downstream proteins and miR-20a-3p were increased significantly, but the expression of c-FLIP was decreased. miR-20a-3p could target c-FLIP. BMSCs-EVs inhibited the growth of HCC cells, decreased c-FLIP expression, increased TRAIL levels, and promote the of HCC cell apoptosis. BMSCs-EVs with overexpressing miR-20a-3p further enhanced the apoptotic effect of HCC cells in vitro and in vivo.

CONCLUSION

BMSCs-EVs-carried miR-20a-3p targets c-FLIP and increases TRAIL levels in HCC cells, thus promoting TRAIL-related apoptosis.

2-Deoxy-d-Glucose and Its Analogs: From Diagnostic to Therapeutic Agents

The ability of 2-deoxy-d-glucose (2-DG) to interfere with d-glucose metabolism demonstrates that nutrient and energy deprivation is an efficient tool to suppress cancer cell growth and survival. Acting as a d-glucose mimic, 2-DG inhibits glycolysis due to formation and intracellular accumulation of 2-deoxy-d-glucose-6-phosphate (2-DG6P), inhibiting the function of hexokinase and glucose-6-phosphate isomerase, and inducing cell death. In addition to glycolysis inhibition, other molecular processes are also affected by 2-DG. Attempts to improve 2-DG’s drug-like properties, its role as a potential adjuvant for other chemotherapeutics, and novel 2-DG analogs as promising new anticancer agents are discussed in this review.

Cancer Metabolism as a Mechanism of Treatment Resistance and Potential Therapeutic Target in Hepatocellular Carcinoma

Various molecular targeted therapies and diagnostic modalities have been developed for the treatment of hepatocellular carcinoma (HCC); however, HCC still remains a difficult malignancy to cure. Recently, the focus has shifted to cancer metabolism for the diagnosis and treatment of various cancers, including HCC. In addition to conventional diagnostics, the measurement of enhanced tumor cell metabolism using F-18 fluorodeoxyglucose (18F-FDG) for increased glycolysis or C-11 acetate for fatty acid synthesis by positron emission tomography/computed tomography (PET/CT) is well established for clinical management of HCC. Unlike tumors displaying the Warburg effect, HCCs vary substantially in terms of 18F-FDG uptake, which considerably reduces the sensitivity for tumor detection. Accordingly, C-11 acetate has been proposed as a complementary radiotracer for detecting tumors that are not identified by 18F-FDG. In addition to HCC diagnosis, since the degree of 18F-FDG uptake converted to standardized uptake value (SUV) correlates well with tumor aggressiveness, 18F-FDG PET/CT scans can predict patient outcomes such as treatment response and survival with an inverse relationship between SUV and survival. The loss of tumor suppressor genes or activation of oncogenes plays an important role in promoting HCC development, and might be involved in the "metabolic reprogramming" of cancer cells. Mutations in various genes such as TERT, CTNNB1, TP53, and Axin1 are responsible for the development of HCC. Some microRNAs (miRNAs) involved in cancer metabolism are deregulated in HCC, indicating that the modulation of genes/miRNAs might affect HCC growth or metastasis. In this review, we will discuss cancer metabolism as a mechanism for treatment resistance, as well as an attractive potential therapeutic target in HCC.

Bitterness in sugar: O-GlcNAcylation aggravates pre-B acute lymphocytic leukemia through glycolysis via the PI3K/Akt/c-Myc pathway

Abnormal cellular energetics has emerged as a hallmark of cancer cells. Deregulating aerobic glycolysis can alter multiple metabolic and signaling pathways in cancer cells, and trigger unlimited growth and proliferation. Accumulating evidence suggests that elevated levels of protein modification with β-N-acetylglucosamine (O-GlcNAcylation) along with dysregulation of O-GlcNAc transferase (OGT) and/or O-GlcNAcase (OGA) levels may act as a nutrient sensor in cancer cells. However, the underlying mechanism of O-GlcNAcylation and the relationship between O-GlcNAcylation and glycolysis are largely unknown in pre-B acute lymphocytic leukemia (pre-B-ALL). In this study, CD19⁺ bone marrow mononuclear cells (BM-MNCs) from untreated pre-B-ALL patients displayed increased O-GlcNAcylation levels, upregulated OGT, and downregulated OGA. Patients with higher lactate dehydrogenase (LDH) levels exhibited higher O-GlcNAcylation levels with OGT upregulation and overactivation of the PI3K/Akt/c-Myc pathway. The extracellular acidification rate (ECAR) and the mRNA expression of key enzymes in glycolysis were determined to assess glycolysis activation. Our results revealed the existence of abnormal glycolysis in the CD19⁺ BM-MNCs of pre-B-ALL patients. The knockdown of OGT decreased the ECAR and downregulated glycolysis-related enzymes in Nalm-6 cells via the PI3K/Akt/c-Myc pathway. The suppression of OGT slowed the rate of proliferation and induced apoptosis in Nalm-6 cells. The glycolysis inhibitor 2-deoxy-D-glucose induced cytotoxicity of Nalm-6 cells, which was potentiated by OGT-siRNA. These findings suggested that O-GlcNAcylation could be a hallmark of pre-B-ALL, which has considerable therapeutic potential in clinical practice.

FLIP(L) is critical for aerobic glycolysis in hepatocellular carcinoma

Background

Tumor cells use aerobic glycolysis to rapidly generate ATP and growth substrate which expenses a large amount of glucose. However, how tumor cells take in enough glucose from the tumor microenvironment of insufficient blood supply remains poorly understood. The cellular FLICE-like inhibitory protein (FLIP), a cell apoptosis inhibiting molecule, is highly expressed in hepatocellular carcinoma (HCC) and is implicated in HCC development.

Methods

The effects of FLIP_L (the long form of FLIP) on aerobic glycolysis and glucose uptake were assessed in HCC cells and xenograft tumors. The correlations between FLIP_L expression and sodium/glucose cotransporter 1 (SGLT1) expression in clinical HCC tissues were analyzed. The consequences of FLIP_L-induced regulation of SGLT1 at the transcription and translation levels and the interaction between FLIP_L and SGLT1 were examined. FLIP_L-mediated tolerance upon glucose limitation and its mechanism were detected.

Results

We report a novel role for FLIP_L in promoting the aerobic glycolysis of HCC cells. FLIP_L overexpression induced a significant increase in cell aerobic glycolysis indexes including glucose uptake, glucose consumption, and lactate production. FLIP_L co-localized and interacted with SGLT1, a major active glucose transporter in HCC cells. FLIP_L increased the stability of SGLT1 protein by inhibiting its ubiquitination and degradation. The expression level of FLIP_L was positively correlated with the expression level of SGLT1 in 79 HCC tissues from surgical operation. Furthermore, FLIP_L increased cell tolerance ability and decreased cell apoptosis to low glucose by regulating SGLT1.

Conclusions

Our results indicate that FLIP_L plays an essential role in HCC aerobic glycolysis and that SGLT1 is required for FLIP_L-modulated tumor proliferation under low glucose conditions. Targeting the actions of FLIP_L in cell glucose-dependent aerobic glycolysis may provide an attractive strategy for therapeutic intervention in HCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0358-3) contains supplementary material, which is available to authorized users.