Long-term prognostic implications and therapeutic target role of hexokinase II in patients with nasopharyngeal carcinoma

Let-7g Upregulation Attenuated the KRAS-PI3K-Rac1-Akt Axis-Mediated Bioenergetic Functions

The aberrant activation of signaling pathways contributes to cancer cells with metabolic reprogramming. Thus, targeting signaling modulators is considered a potential therapeutic strategy for cancer. Subcellular fractionation, coimmunoprecipitation, biochemical analysis, and gene manipulation experiments revealed that decreasing the interaction of kirsten rat sarcoma viral oncogene homolog (KRAS) with p110α in lipid rafts with the use of naringenin (NGN), a citrus flavonoid, causes lipid raft-associated phosphatidylinositol 3-kinase (PI3K)-GTP-ras-related C3 botulinum toxin substrate 1 (Rac1)-protein kinase B (Akt)-regulated metabolic dysfunction of glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), leading to apoptosis in human nasopharyngeal carcinoma (NPC) cells. The use of lethal-7g (let-7g) mimic and let-7g inhibitor confirmed that elevated let-7g resulted in a decrease in KRAS expression, which attenuated the PI3K-Rac1-Akt-BCL-2/BCL-xL-modulated mitochondrial energy metabolic functions. Increased let-7g depends on the suppression of the RNA-specificity of monocyte chemoattractant protein-induced protein-1 (MCPIP1) ribonuclease since NGN specifically blocks the degradation of pre-let-7g by NPC cell-derived immunoprecipitated MCPIP1. Converging lines of evidence indicate that the inhibition of MCPIP1 by NGN leads to let-7g upregulation, suppressing oncogenic KRAS-modulated PI3K-Rac1-Akt signaling and thereby impeding the metabolic activities of aerobic glycolysis and mitochondrial OXPHOS.

Cellular signals integrate cell cycle and metabolic control in cancer

Growth factors are the small peptides that can promote growth, differentiation, and survival of most living cells. However, aberrant activation of receptor tyrosine kinases by GFs can generate oncogenic signals, resulting in oncogenic transformation. Accumulating evidence support a link between GF/RTK signaling through the major signaling pathways, Ras/Erk and PI3K/Akt, and cell cycle progression. In response to GF signaling, the quiescent cells in the G₀ stage can re-enter the cell cycle and become the proliferative stage. While in the proliferative stage, tumor cells undergo profound changes in their metabolism to support biomass production and bioenergetic requirements. Accumulating data show that the cell cycle regulators, specifically cyclin D, cyclin B, Cdk2, Cdk4, and Cdk6, and anaphase-promoting complex/cyclosome (APC/C-Cdh1) play critical roles in modulating various metabolic pathways. These cell cycle regulators can regulate metabolic enzyme activities through post-translational mechanisms or the transcriptional factors that control the expression of the metabolic genes. This fine-tune control allows only the relevant metabolic pathways to be active in a particular phase of the cell cycle, thereby providing suitable amounts of biosynthetic precursors available during the proliferative stage. The imbalance of metabolites in each cell cycle phase can induce cell cycle arrest followed by p53-induced apoptosis.

Metabolic Reprogramming and Immune Evasion in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant tumor of the nasopharynx mainly characterized by geographic distribution and EBV infection. Metabolic reprogramming, one of the cancer hallmarks, has been frequently reported in NPCs to adapt to internal energy demands and external environmental pressures. Inevitably, the metabolic reprogramming within the tumor cell will lead to a decreased pH value and diverse nutritional supplements in the tumor-infiltrating micro-environment incorporating immune cells, fibroblasts, and endothelial cells. Accumulated evidence indicates that metabolic reprogramming derived from NPC cells may facilitate cancer progression and immunosuppression by cell-cell communications with their surrounding immune cells. This review presents the dysregulated metabolism processes, including glucose, fatty acid, amino acid, nucleotide metabolism, and their mutual interactions in NPC. Moreover, the potential connections between reprogrammed metabolism, tumor immunity, and associated therapy would be discussed in this review. Accordingly, the development of targets on the interactions between metabolic reprogramming and immune cells may provide assistances to overcome the current treatment resistance in NPC patients.

GSH-Responsive Nanoprodrug to Inhibit Glycolysis and Alleviate Immunosuppression for Cancer Therapy

Blocking energy metabolism of cancer cells and simultaneously stimulating the immune system to perform immune attack are significant for cancer treatment. However, how to potently deliver different drugs with these functions remains a challenge. Herein, we synthesized a nanoprodrug formed by a F127-coated drug dimer to inhibit glycolysis of cancer cells and alleviate the immunosuppressive microenvironment. The dimer was delicately constructed to connect lonidamine (LND) and NLG919 by a disulfide bond which can be cleaved by excess GSH to release two drugs. LND can decrease the expression of hexokinase II and destroy mitochondria to restrain glycolysis for energy supply. NLG919 can reduce the accumulation of kynurenine and the number of regulatory T cells, thus alleviating the immunosuppressive microenvironment. Notably, the consumption of GSH by disulfide bond increased the intracellular oxidative stress and triggered immunogenic cell death of cancer cells. This strategy can offer more possibilities to explore dimeric prodrugs for synergistic cancer therapy.

Prognostic value of glycolysis markers in head and neck squamous cell carcinoma: a meta-analysis

Glycolysis markers including glucose transporter 1 (GLUT1), monocarboxylate transporter 4 (MCT4), hexokinase 2 (HK2), pyruvate kinase M2 (PKM2) and glucose transporter 4 (GLUT4) play vital roles in head and neck squamous cell carcinoma (HNSCC). However, their prognostic value in HNSCC is still controversial. In this meta-analysis, we searched the PubMed, Web of Science and Cochrane Library databases and included thirty-seven studies (3272 patients) that met the inclusion criteria. Higher expression levels of the glycolysis markers in tumor tissues correlated with poorer overall survival (OS; P < 0.001), disease-free survival (DFS; P = 0.03) and recurrence-free survival (RFS; P < 0.001) of HNSCC patients. Subgroup and sensitivity analyses demonstrated that higher expression levels of GLUT1 (P < 0.001), MCT4 (P = 0.002), HK2 (P = 0.002) and PKM2 (P < 0.001) correlated with poorer OS among HNSCC patients. Higher expression of MCT4 (P < 0.001) and PKM2 (P = 0.008) predicted poorer DFS among HNSCC patients. However, GLUT4 expression levels did not associate with clinical outcomes in HNSCC patients. These results demonstrate that glycolysis markers, such as GLUT1, MCT4, HK2 and PKM2, are potential prognostic predictors and therapeutic targets in HNSCC.

The role of hexokinase in cancer

A thorough understanding of the processes occurring in cancer cells is necessary to make cancer treatment as effective as possible. Changes in cellular metabolism in relation to normal cells are considered particularly important. One of the most interesting and promising areas is glucose metabolism and the factors affecting this process, with special emphasis on the potential role of hexokinases, especially the isoform II of this enzyme. Hexokinases (HK) are transferase enzymes involved in the process of glycolysis. Hexokinase II (HK II) plays an important role in initiating and maintaining the glycolysis process at a high level of efficiency, which is crucial for the growth and proliferation of cancer cells. An increase in the number of copies of the HK II gene and increased transcription of this enzyme resulting in the suppression of apoptosis and the enhancement of cell proliferation have been found in tumor cells. Hexokinase II also participates in the Crabtree effect by affecting the amount of ATP and thus the efficiency of the Ca2+ removal process outside the cell membrane by Ca2+ ATPase. Overexpression of HK II has thus far been found in pancreatic cancer, gastric cancer, breast cancer, squamous cell carcinoma of the larynx, glioblastoma multiforme, ovarian cancer and biliary tract cancer, indicating the possible key role of this enzyme in their formation and progression and providing the basis for seeking potential benefits of cancer treatment using HK II as a target of new drugs.

Metabolic reprogramming and disease progression in cancer patients

Genomics has contributed to the treatment of a fraction of cancer patients. However, there is a need to profile the proteins that define the phenotype of cancer and its pathogenesis. The reprogramming of metabolism is a major trait of the cancer phenotype with great potential for prognosis and targeted therapy. This review overviews the major changes reported in the steady-state levels of proteins of metabolism in primary carcinomas, paying attention to those enzymes that correlate with patients' survival. The upregulation of enzymes of glycolysis, pentose phosphate pathway, lipogenesis, glutaminolysis and the antioxidant defense is concurrent with the downregulation of mitochondrial proteins involved in oxidative phosphorylation, emphasizing the potential of mitochondrial metabolism as a promising therapeutic target in cancer. We stress that high-throughput quantitative expression profiling of differentially expressed proteins in large cohorts of carcinomas paired with normal tissues will accelerate translation of metabolism to a successful personalized medicine in cancer.

Poor prognosis of hexokinase 2 overexpression in solid tumors of digestive system: a meta-analysis

Several previous studies have reported the prognostic value of hexokinase 2 (HK2) in digestive system tumors. However, these studies were limited by the small sample sizes and the results were inconsistent among them. Therefore, we conducted a meta-analysis based on 15 studies with 1932 patients to assess the relationship between HK2 overexpression and overall survival (OS) of digestive system malignancies. The relationship of HK2 and clinicopathological features was also evaluated. Hazard ratio (HR) or odds ratio (OR) with its 95% confidence intervals (CI) were calculated to estimate the effect size. Positive HK2 expression showed poor OS in all tumor types (HR = 1.75 [1.41-2.18], P < 0.001). When stratified by tumor type, the impact of HK2 overexpression on poor prognosis was observed in gastric cancer (HR = 1.77 [1.25-2.50], P < 0.001), hepatocellular carcinoma (HR = 1.87 [1.58-2.21], P < 0.001), and colorectal cancer (HR = 2.89 [1.62-5.15], P < 0.001), but not in pancreatic ductal adencarcinoma (HR = 1.11 [0.58-2.11], P = 0.763). Furthermore, high HK2 expression was significantly associated with some phenotypes of tumor aggressiveness, such as large tumor size (OR = 2.03 [1.10-3.74], P = 0.024), positive lymph node metastasis (OR = 2.05 [1.39-3.02], P < 0.001), advanced clinical stage (OR = 2.17 [1.21-3.89], P = 0.009) and high alpha fetoprotein level (OR = 1.47 [1.09-2.02] P = 0.013). In summary, HK2 might act as a prognostic indicator and a potential therapeutic target of these digestive system cancers.

Effect of HK2, PKM2 and LDHA on Cetuximab efficacy in metastatic colorectal cancer

Although hexokinase (HK) 2, pyruvate kinase muscle (PKM) isozyme 2 and lactate dehydrogenase (LDH) A predict the efficacy of medicines in various solid tumors, their ability to predict the efficacy of cetuximab in metastatic colorectal cancer (mCRC) remains unclear. mCRC patients with pathological specimens who received cetuximab and chemotherapy from 2005 to 2015 in the present institution were enrolled. Immunohistochemistry was used to detect HK2, PKM2 and LDHA expression. SPSS20 was used for statistical analysis. A total of 68 patients were included; 33 received cetuximab plus chemotherapy as first-line therapy, and the rest, as second- or later-line therapy. HK2 expression levels were increased in cancer compared with normal tissue (75.4% vs. 40%; P<0.001), however PKM2 (P=0.243) and LDHA (P=0.067) expression levels were not. For progression-free survival (PFS) with first-line cetuximab plus chemotherapy, patients with high HK2 expression exhibited longer PFS compared with those with low HK2 expression (23.9 months vs. 6.9 months; P=0.021). However, this positive association was absent in 35 cases administered first-line chemotherapy alone (13.4 months vs. 13.5 months; P=0.539). LDHA expression was associated with the PFS of patients receiving first-line chemotherapy (18.3 and 10.1 months for high and low expression, respectively; P=0.005), whereas this association was absent in cetuximab plus chemotherapy cases (19.9 months vs. 12 months; P=0.522). Furthermore, high LDHA expression correlated with high overall response rate (ORR) (72.2% vs. 15.4%, P=0.006) for chemotherapy, however not disease control rate (DCR) (P=0.074). Neither DCR nor ORR were associated with HK2 expression. PKM2 expression did not affect PFS, DCR or ORR. LDHA expression (P=0.005), pathological differentiation (P=0.019) and synchronous/metachronous metastasis (P=0.014) were independent predictive factors of PFS for all first-line patients, and tumor differentiation (P=0.002) was associated with overall survival (OS) in multivariate analysis. HK2, PKM2 and LDHA did not impact OS. It was concluded that HK2 expression was increased in colorectal cancer tissue and may predict cetuximab efficacy and LDHA for chemotherapy treatment of mCRC.

Inhibition of histone deacetylases induces formation of multipolar spindles and subsequent p53-dependent apoptosis in nasopharyngeal carcinoma cells

Histone deacetylases (HDACs) play crucial roles in the initiation and progression of cancer, offering a promising target for cancer therapy. HDACs inhibitor MGCD0103 (MGCD) exhibits effective anti-tumor activity by blocking proliferation and inducing cell death in malignant cells. However, the molecular mechanisms of HDACs inhibition induces cell death have not been well elucidated. In this study, we showed that MGCD effectively restored histone acetylation, suppressed cell growth and induced apoptosis in two-dimensional (2D) and three-dimensional (3D) cultured CNE1 and CNE2 nasopharyngeal carcinoma (NPC) cells. Importantly, MGCD arrested cell cycle at mitosis (M) phase with formation of multipolar spindles, which was associated with activated p53-mediated postmitotic checkpoint pathway to induce apoptotic cell death. Moreover, MGCD-induced apoptosis was decreased by inhibition of p53 using short interfering RNA (siRNA), suggesting that p53 was required for MGCD-induced cell apoptosis. Consistently, MGCD in combination with Nutlin-3, a MDM2 inhibitor showed synergistic effect on inducing apoptosis in 2D and 3D cultured CNE2 cells. Collectively, our data revealed that MGCD induced p53-dependent cell apoptosis following formation of multipolar spindles in NPC cells, suggesting the therapeutic potential of combinations of HDACs and MDM2 inhibitors for NPC treatment.

Chrysin inhibited tumor glycolysis and induced apoptosis in hepatocellular carcinoma by targeting hexokinase-2

Background

Hexokinase-2(HK-2) plays dual roles in glucose metabolism and mediation of cell apoptosis, making it an attractive target for cancer therapy. Chrysin is a natural flavone found in plant extracts which are widely used as herb medicine in China. In the present study, we investigated the antitumor activity of chrysin against hepatocellular carcinoma (HCC) and the role of HK-2 played for chrysin to exert its function.

Methods

The expression of HK-2 in HCC cell line and tumor tissue was examined by western blotting and immunohistochemistry staining. The activities of chrysin against HCC cell proliferation and tumor glycolysis were investigated. Chrysin-induced apoptosis was analyzed by flow cytometry. The effect of chrysin on HK-2 expression and the underlying mechanisms by which induced HCC cell apoptosis were studied. In HK-2 exogenous overexpression cell, the changes of chrysin-induced cell apoptosis and glycolysis suppression were investigated. HCC cell xenograft model was used to confirm the antitumor activity of chrysin in vivo and the effect on HK-2 was tested in chrysin-treated tumor tissue.

Results

In contrast with normal cell lines and tissue, HK-2 expression was substantially elevated in the majority of tested HCC cell lines and tumor tissue. Owing to the decrease of HK-2 expression, glucose uptake and lactate production in HCC cells were substantially inhibited after exposure to chrysin. After chrysin treatment, HK-2 which combined with VDAC-1 on mitochondria was significantly declined, resulting in the transfer of Bax from cytoplasm to mitochondria and induction of cell apoptosis. Chrysin-mediated cell apoptosis and glycolysis suppression were dramatically impaired in HK-2 exogenous overexpression cells. Tumor growth in HCC xenograft models was significantly restrained after chrysin treatment and significant decrease of HK-2 expression was observed in chrysin-treated tumor tissue.

Conclusion

Through suppressing glycolysis and inducing apoptosis in HCC, chrysin, or its derivative has a promising potential to be a novel therapeutic for HCC management, especially for those patients with high HK-2 expression.

Prognostic Significance of the Metabolic Marker Hexokinase-2 in Various Solid Tumors: A Meta-Analysis

Objective

Recently, numerous studies have reported that hexokinase-2 (HK2) is aberrantly expressed in cancer, indicating that HK2 plays a pivotal role in the development and progression of cancer. However, its prognostic significance in solid tumor remains unclear. Accordingly, we performed a meta-analysis to assess the prognostic value of HK2 in solid tumor.

Methods

Eligible studies were identified using PubMed, Embase, and Web of Science databases. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) or progression-free survival (PFS)/disease-free survival (DFS)/relapse-free survival (RFS) were estimated with random effects or fixed effects models, respectively. Subgroup analysis was also performed according to patients’ ethnicities, tumor types, detection methods, and analysis types.

Results

Data from 21 included studies with 2532 patients were summarized. HK2 overexpression was significantly associated with worse OS (pooled HR = 1.90, 95% CI = 1.51–2.38, p < 0.001) and PFS (pooled HR = 2.91, 95% CI = 2.02–4.22, p < 0.001) in solid tumor. As to a specific form of cancer, the negative effect of HK2 on OS was observed in hepatocellular carcinoma (pooled HR = 2.06, 95% CI = 1.67–2.54, p < 0.001), gastric cancer (pooled HR = 1.72, 95% CI = 1.09–2.71, p = 0.020), colorectal cancer (pooled HR = 2.89, 95% CI = 1.62–5.16, p < 0.001), but not in pancreatic cancer (pooled HR = 1.13, 95% CI = 0.28–4.66, p = 0.864). No publication bias was found in the included studies for OS (Begg’s test, p = 0.325; Egger’s test, p = 0.441).

Conclusion

In this meta-analysis, we identified that elevated HK2 expression was significantly associated with shorter OS and PFS in patients with solid tumor, but the association varies according to cancer type.

High expression of hexokinase domain containing 1 is associated with poor prognosis and aggressive phenotype in hepatocarcinoma

Rapid progress and metastasis remain the major treatment failure modes of hepatocarcinoma (HCC). Unfortunately, the underlying molecular mechanisms of hepatoma cell proliferation and migration are poorly understood. Metabolic abnormalities play critical roles in tumorigenesis and progression. Hexokinase domain containing 1 (HKDC1) catalyzes the phosphorylation of glucose. However, the functions and mechanisms of HKDC1 in cancer remain unknown. In this study, real-time RT-PCR and Western blotting assays were used to detect the HKDC1 expression levels in HCC tissues and cell lines. The Oncomine™ Cancer Microarray Database was applied to analysis the correlations between HKDC1 expression and HCC clinical characteristics. MTT and Transwell migration assays were performed to determine the functions of HKDC1 in HCC cells. The effect of HKDC1 on Wnt/β-catenin signaling pathway was assessed using Western blotting assay. In this study, we found that HKDC1 expression levels were elevated in HCC tissues compared with the adjacent tissues. HCC patients with high expression levels of HKDC1 had poor overall survival (OS). Furthermore, higher HKDC1 levels also predicted a worse OS of patients within solitary, elevated pre-operated serum alpha fetoprotein (AFP) level and higher tumor diameter. Moreover, silencing HKDC1 suppressed HCC cells proliferation and migration in vitro. Downregulated HKDC1 expression repressed β-Catenin and c-Myc expression, which indicates that silencing HKDC1 may reduce proliferation and migration via inhibiting the Wnt/β-catenin signaling pathway in HCC. In summary, HKDC1 provides further insight into HCC tumor progression and may provide a novel prognostic biomarker and therapeutic target for HCC treatment.