Inactivation of HMGCL promotes proliferation and metastasis of nasopharyngeal carcinoma by suppressing oxidative stress

miR-1202 regulates BPH-1 cell proliferation, apoptosis, and epithelial-to-mesenchymal transition through targeting HMGCL

Benign prostatic hyperplasia (BPH) is the expansion of the prostate gland that results in urinary symptoms. Both the epithelial-to-mesenchymal transition (EMT) and the Wnt signaling pathway are associated with BPH pathology. In this study, we find that miR-1202 is increased in BPH samples. Overexpression of miR-1202 in TGF-β-treated BPH-1 cells enhances cell survival and DNA synthesis and inhibits cell apoptosis, whereas miR-1202 inhibition partially abolishes the effects of TGF-β on BPH-1 cells. miR-1202 overexpression reduces E-cadherin level but elevates vimentin, N-cadherin, and snail levels, whereas miR-1202 inhibition partially attenuates the effects of TGF-β on EMT markers. Regarding the Wnt/β-catenin pathway, miR-1202 overexpression significantly enhances, whereas miR-1202 inhibition partially decreases, the promotive effects of TGF-β on Wnt1, c-Myc, and cyclin D1 proteins. 3-Hydroxy-3-methylglutaryl-CoA lyase (HMGCL) is a direct downstream target of miR-1202, and miR-1202 inhibits HMGCL expression through binding to its 3'UTR. Overexpression of HMGCL significantly reduces the effect of miR-1202 overexpression on the phenotypes of BPH-1 cells by inhibiting cell survival and promoting apoptosis. Similarly, HMGCL overexpression has the opposite effects on EMT markers and the Wnt/β-catenin signaling, and markedly alleviates the effects of miR-1202 overexpression. Finally, in the BPH rat model, Ki67 and vimentin levels are elevated, but E-cadherin and HMGCL levels are reduced. In conclusion, miR-1202 is upregulated in benign prostatic hyperplasia; miR-1202 enhances epithelial cell proliferation, suppresses cell apoptosis, and promotes EMT by targeting HMGCL. The Wnt/β-catenin pathway may participate in the miR-1202/HMGCL axis-mediated regulation of BPH-1 cell phenotypes.

First report on in-depth genome and comparative genome analysis of a metal-resistant bacterium Acinetobacter pittii S-30, isolated from environmental sample

A newly isolated bacterium Acinetobacter pittii S-30 was recovered from waste-contaminated soil in Ranchi, India. The isolated bacterium belongs to the ESKAPE organisms which represent the major nosocomial pathogens that exhibit high antibiotic resistance. Furthermore, average nucleotide identity (ANI) analysis also showed its closest match (>95%) to other A. pittii genomes. The isolate showed metal-resistant behavior and was able to survive up to 5 mM of ZnSO4. Whole genome sequencing and annotations revealed the occurrence of various genes involved in stress protection, motility, and metabolism of aromatic compounds. Moreover, genome annotation identified the gene clusters involved in secondary metabolite production (biosynthetic gene clusters) such as arylpolyene, acinetobactin like NRP-metallophore, betalactone, and hserlactone-NRPS cluster. The metabolic potential of A. pittii S-30 based on cluster of orthologous, and Kyoto Encyclopedia of Genes and Genomes indicated a high number of genes related to stress protection, metal resistance, and multiple drug-efflux systems etc., which is relatively rare in A. pittii strains. Additionally, the presence of various carbohydrate-active enzymes such as glycoside hydrolases (GHs), glycosyltransferases (GTs), and other genes associated with lignocellulose breakdown suggests that strain S-30 has strong biomass degradation potential. Furthermore, an analysis of genetic diversity and recombination in A. pittii strains was performed to understand the population expansion hypothesis of A. pittii strains. To our knowledge, this is the first report demonstrating the detailed genomic characterization of a heavy metal-resistant bacterium belonging to A. pittii. Therefore, the A. pittii S-30 could be a good candidate for the promotion of plant growth and other biotechnological applications.

Downregulation of NEBL promotes migration and invasion of clear cell renal cell carcinoma by inducing epithelial-mesenchymal transition

As a member of the nebulin protein family and a structural protein of cytoskeleton, NEBL plays an important role in cardiac diseases. Recently, literature have reported the involvement of NEBL in the occurrence and development of various cancers except clear cell renal cell carcinoma (ccRCC). In this study, we found that mRNA and protein of NEBL are downregulated remarkably in ccRCC tissues based on both the TCGA database and clinical samples we collected. The areas under curve values of NEBL analyzed based on the TCGA database, qRT-PCR and IHC results were 0.9376, 0.9733 and 0.9807, respectively. The lower mRNA level of NEBL was associated with worse outcomes in ccRCC patients. When overexpressing NEBL in ccRCC cell lines, the proliferation, migration and invasion of ccRCC cells were suppressed significantly, suggesting a tumor suppressor role of NEBL. In addition, we identified that NEBL is closely related to epithelial-mesenchymal transition (EMT), thereby reducing the motility of ccRCC cells. Furthermore, the lower expression of NEBL was correlated with ccRCC patients with distant organ metastasis. In summary, we firstly described the aberrant expression of NEBL and revealed its tumor suppressor role in ccRCC. Our data support that NEBL could serve as a valuable diagnostic and prognostic biomarker in ccRCC, as well as a promising therapeutic target.

HIGD1A inactivated by DNA hypermethylation promotes invasion of kidney renal clear cell carcinoma

Hypoxia contributes to the tumorigenesis and metastasis of the tumor. However, the detailed mechanisms underlying hypoxia and kidney renal clear cell carcinoma (KIRC) development and progression remain unclear. Here, we investigated the role of the system HIG1 hypoxia inducible domain family member 1 A (HIGD1A) in the proliferation and metastasis of KIRC and elucidated the underlying molecular mechanisms. The expression of HIGD1A is significantly downregulated in KIRC due to promoter hypermethylation. HIGD1A could serve as a valuable diagnostic biomarker in KIRC. In addition, ectopic overexpression of HIGD1A significantly suppressed the growth and invasive capacity of KIRC cells in vitro under normal glucose conditions. Interestingly, the suppressive efficacy in invasion is much more significant when depleted glucose, but not in proliferation. Furthermore, mRNA expression of HIGD1A positively correlates with CDH1 and EPCAM, while negatively correlated with VIM and SPARC, indicating that HIGD1A impedes invasion of KIRC by regulating epithelial-mesenchymal transition (EMT). Our data suggest that HIGD1A is a potential diagnostic biomarker and tumor suppressor in KIRC.

T cell-mediated tumor killing patterns in head and neck squamous cell carcinoma identify novel molecular subtypes, with prognosis and therapeutic implications

As an important process in cancer immunotherapy, T cell-mediated tumor killing (TTK) enhances the immune response of patients. However, the role of TTK in Head and Neck Squamous Cell Carcinoma (HNSCC) patients still needs further exploration. Therefore, we comprehensively analyzed the gene expression information and clinical characteristics of 1063 HNSCC in five cohorts. Univariate regression, differential expression analysis, and gene mutation profiling were combined to identify the important genes regulating the sensitivity of tumor cells to T cell-mediated killing (GSTTK) in HNSCC. A total of 20 GSTTK were identified as important genes of HNSCC. Patients were divided into C1 and C2 subgroups (TTK patterns) and displayed significant prognostic differences. Patients with C2 subtype had dismal prognosis characteristic compared to C1 subtype in all validation cohorts. Patients with C1 subgroup exhibited robust immune profile and C1 subgroup patients were significantly enriched in metabolically relevant functions. Notably, the multi-omics analysis found that C1 subgroup have higher mutation burden and C2 subgroup patients had significantly higher copy number variation. Drug sensitivity analysis found that multiple first-line chemotherapeutic drugs were more sensitive in patients with subgroup C1. In conclusion, the establishment of GSTTK provides guidance and assistance to clinicians in the personalized management and treatment of HNSCC patients.

Phosphorylation by IKKβ Promotes the Degradation of HMGCL via NEDD4 in Lung Cancer

Inflammation and metabolic reprogramming are hallmarks of cancer. How inflammation regulates cancer metabolism remains poorly understood. In this study, we found that 3-hydroxy-3-methylglutaryl-CoA lyase (HMGCL), the enzyme that catalyzes the catabolism of leucine and promotes the synthesis of ketone bodies, was downregulated in lung cancer. Downregulation of HMGCL was associated with a larger tumor size and a shorter overall survival time. In a functional study, overexpression of HMGCL increased the content of β-hydroxybutyrate (β-HB) and inhibited the tumorigenicity of lung cancer cells, and deletion of HMGCL promoted de novo tumorigenesis in KP (Kras^G12D;P53^f/f) mice. Mechanistically, tumor necrosis factor α (TNFα) treatment decreased the HMGCL protein level, and IKKβ interacted with HMGCL and phosphorylated it at Ser258, which destabilized HMGCL. Moreover, NEDD4 was identified as the E3 ligase for HMGCL and promoted its degradation. In addition, mutation of Ser258 to alanine inhibited the ubiquitination of HMGCL by NEDD4 and thus inhibited the anchorage-independent growth of lung cancer cells more efficiently than did wild-type HMGCL. In summary, this study demonstrated a link between TNFα-mediated inflammation and cancer metabolism.

HMGCL-induced β-hydroxybutyrate production attenuates hepatocellular carcinoma via DPP4-mediated ferroptosis susceptibility

BACKGROUND

Metabolic disorder is an essential characteristic of tumor development. Ketogenesis is a heterogeneous factor in multiple cancers, but the effect of ketogenesis on hepatocellular carcinoma (HCC) is elusive.

METHODS

We aimed to explain the role of ketogenesis-related hydroxy-methyl-glutaryl-CoA lyase (HMGCL) on HCC suppression. Expression pattern of HMGCL in HCC specimens was evaluated by immunohistochemistry (IHC). HMGCL was depleted or overexpressed in HCC cells to investigate the functions of HMGCL in vitro and in vivo. The anti-tumor function of HMGCL was studied in subcutaneous xenograft and Trp53^Δhep/Δhep; c-Myc-driven HCC mouse models. The mechanism of HMGCL-mediated tumor suppression was studied by IHC, western blot (WB) and Cut & Tag.

RESULTS

HMGCL depletion promoted HCC proliferation and metastasis, whereas its overexpression reversed this trend. As HMGCL catalyzes β-hydroxy-butyric acid (β-OHB) production, we discovered that HMGCL increased acetylation at histone H3K9, which further promoted the transcription of dipeptidyl peptidase 4 (DPP4), a key protein maintains intracellular lipid peroxidation and iron accumulation, leading to HCC cells vulnerability to erastin- and sorafenib-induced ferroptosis.

CONCLUSION

Our study identified a critical role of HMGCL on HCC suppression, of which HMGCL regulated H3K9 acetylation through β-OHB and modulating the expression of DPP4 in a dose-dependent manner, which led to ferroptosis in HCC cells.

Molecular Mechanisms for Ketone Body Metabolism, Signaling Functions, and Therapeutic Potential in Cancer

The ketone bodies (KBs) β-hydroxybutyrate and acetoacetate are important alternative energy sources for glucose during nutrient deprivation. KBs synthesized by hepatic ketogenesis are catabolized to acetyl-CoA through ketolysis in extrahepatic tissues, followed by the tricarboxylic acid cycle and electron transport chain for ATP production. Ketogenesis and ketolysis are regulated by the key rate-limiting enzymes, 3-hydroxy-3-methylglutaryl-CoA synthase 2 and succinyl-CoA:3-oxoacid-CoA transferase, respectively. KBs participate in various cellular processes as signaling molecules. KBs bind to G protein-coupled receptors. The most abundant KB, β-hydroxybutyrate, regulates gene expression and other cellular functions by inducing post-translational modifications. KBs protect tissues by regulating inflammation and oxidative stress. Recently, interest in KBs has been increasing due to their potential for treatment of various diseases such as neurological and cardiovascular diseases and cancer. Cancer cells reprogram their metabolism to maintain rapid cell growth and proliferation. Dysregulation of KB metabolism also plays a role in tumorigenesis in various types of cancer. Targeting metabolic changes through dietary interventions, including fasting and ketogenic diets, has shown beneficial effects in cancer therapy. Here, we review current knowledge of the molecular mechanisms involved in the regulation of KB metabolism and cellular signaling functions, and the therapeutic potential of KBs and ketogenic diets in cancer.

The Association of Ketolytic Enzymes Gene Expression Levels with Mitochondrial Activity and Content in Oral Squamous Cell Carcinoma

Background: Recent studies have pointed to the anti-tumour effects of a ketogenic diet (KD) in cancer. It is believed that patients with low ketolytic Enzymes gene expression levels are more sensitive and may respond better to the KD therapy. However, the ketolytic Enzymes gene expression levels and their association with mitochondrial activity and content in oral squamous cell carcinoma (OSCC) is not yet obvious. Therefore, the aim of this study was to explore the potential use of ketolytic enzymes as biomarkers for mitochondrial activity and content. Materials and Methods: Here we aimed to compare the mRNA expression levels of ketolytic enzymes (ACAT1, BDH1, BDH2 and OXCT1) between tumour and adjacent pre-tumor tissues of 16 OSCC patients. Additionally, we examined the association of the mitochondrial ketolytic enzymes, including ACAT1, OXCT1, and BDH1 gene expression with mitochondrial activity and content. Results: Our findings did not show any significant difference in ketolytic gene expression levels between tumour and pre-tumor tissues of OSCC patients. ACAT1 and BDH1 mRNA expression levels were significantly correlated with the mRNA level of ND2 in tumour of OSCC patients. The mRNA levels of ACAT1, BDH1 and BDH2 were not correlated with the mRNA expression of 16srRNA. Conclusion: Our data suggest that mRNA gene expression levels of BDH1 and ACAT1 correlate with the mitochondrial activity in tumour of OSCC patients. BDH2 mRNA level significantly anti-correlate with tumour grade. We offer clues on the potential of ACAT1 as a biomarker of mitochondrial activity, but future studies are needed to establish this concept.

Decreased expression of 3-hydroxybutyrate dehydrogenase 1 is a prognostic marker and promotes tumor progression in hepatocellular carcinoma

Growing evidence indicates that altered metabolism represents the hallmark of hepatocellular carcinoma (HCC). The mitochondrial 3-hydroxybutyrate dehydrogenase 1 (BDH1) is a key catalytic enzyme in ketogenesis with unknown roles in HCC. Hundred and four tissue sample pairs (HCC tissues, n = 104; matched normal tissues, n = 104) were obtained and analyzed with immunohistochemical (IHC) staining to investigate the clinical and functional role and the diagnostic and prognostic value of BDH1 in HCC. In addition, RNA-Seq datasets from the Tumor Immune Estimation Resource (TIMER) (HCC group, n = 371; normal group, n = 50) and microarray datasets from the Gene Expression Omnibus (GEO) database (HCC tissues, n = 1671; normal tissues, n = 1479) were used to assess BDH1 expression in HCC. Several bioinformatic methods were performed to identify pathways regulated by BDH1. The IHC staining showed that BDH1 expression decreased in HCC tissues (n = 69) compared with that in adjacent normal tissues (n = 35, P < 0.001). Low BDH1 expression was associated with advanced clinical stage (P = 0.033) and vascular invasion (P = 0.007). Moreover, ectopic expression of BDH1 reduced tumor proliferation and suppressed the migration and invasion of HCC cells in vitro. Therefore, our data suggest that BDH1 is a potentially valuable diagnostic biomarker and therapeutic target for HCC.

Targeting mitochondrial metabolism for precision medicine in cancer

During decades, the research field of cancer metabolism was based on the Warburg effect, described almost one century ago. Lately, the key role of mitochondria in cancer development has been demonstrated. Many mitochondrial pathways including oxidative phosphorylation, fatty acid, glutamine, and one carbon metabolism are altered in tumors, due to mutations in oncogenes and tumor suppressor genes, as well as in metabolic enzymes. This results in metabolic reprogramming that sustains rapid cell proliferation and can lead to an increase in reactive oxygen species used by cancer cells to maintain pro-tumorigenic signaling pathways while avoiding cellular death. The knowledge acquired on the importance of mitochondrial cancer metabolism is now being translated into clinical practice. Detailed genomic, transcriptomic, and metabolomic analysis of tumors are necessary to develop more precise treatments. The successful use of drugs targeting metabolic mitochondrial enzymes has highlighted the potential for their use in precision medicine and many therapeutic candidates are in clinical trials. However, development of efficient personalized drugs has proved challenging and the combination with other strategies such as chemocytotoxic drugs, immunotherapy, and ketogenic or calorie restriction diets is likely necessary to boost their potential. In this review, we summarize the main mitochondrial features, metabolic pathways, and their alterations in different cancer types. We also present an overview of current inhibitors, highlight enzymes that are attractive targets, and discuss challenges with translation of these approaches into clinical practice. The role of mitochondria in cancer is indisputable and presents several attractive targets for both tailored and personalized cancer therapy.

Ketogenic HMG-CoA lyase and its product β-hydroxybutyrate promote pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDA) tumor cells are deprived of oxygen and nutrients and therefore must adapt their metabolism to ensure proliferation. In some physiological states, cells rely on ketone bodies to satisfy their metabolic needs, especially during nutrient stress. Here, we show that PDA cells can activate ketone body metabolism and that β-hydroxybutyrate (βOHB) is an alternative cell-intrinsic or systemic fuel that can promote PDA growth and progression. PDA cells activate enzymes required for ketogenesis, utilizing various nutrients as carbon sources for ketone body formation. By assessing metabolic gene expression from spontaneously arising PDA tumors in mice, we find HMG-CoA lyase (HMGCL), involved in ketogenesis, to be among the most deregulated metabolic enzymes in PDA compared to normal pancreas. In vitro depletion of HMGCL impedes migration, tumor cell invasiveness, and anchorage-independent tumor sphere compaction. Moreover, disrupting HMGCL drastically decreases PDA tumor growth in vivo, while βOHB stimulates metastatic dissemination to the liver. These findings suggest that βOHB increases PDA aggressiveness and identify HMGCL and ketogenesis as metabolic targets for limiting PDA progression.

EPHX2 Inhibits Colon Cancer Progression by Promoting Fatty Acid Degradation

Tumor cells use metabolic reprogramming to keep up with the need for bioenergy, biosynthesis, and oxidation balance needed for rapid tumor division. This phenomenon is considered a marker of tumors, including colon cancer (CRC). As an important pathway of cellular energy metabolism, fatty acid metabolism plays an important role in cellular energy supply and oxidation balance, but presently, our understanding of the exact role of fatty acid metabolism in CRC is limited. Currently, no lipid metabolism therapy is available for the treatment of CRC. The establishment of a lipidmetabolism model regulated by oncogenes/tumor suppressor genes and associated with the clinical characteristics of CRC is necessary to further understand the mechanism of fatty acid metabolism in CRC. In this study, through multi-data combined with bioinformatic analysis and basic experiments, we introduced a tumor suppressor gene, EPHX2, which is rarely reported in CRC, and confirmed that its inhibitory effect on CRC is related to fatty acid degradation.

Low-dose perfluorooctanoic acid stimulates steroid hormone synthesis in Leydig cells: Integrated proteomics and metabolomics evidence

Perfluorooctanoic acid (PFOA), one of the well-known perfluoroalkyl substances (PFASs), has been widespread in the environment and associated with male reproductive toxicity. However, the molecular mechanism involved in low-level PFOA-induced male endocrine disruption remains to be elucidated. In this study, we performed a combined proteomics and metabolomics analysis to investigate the proteomic and metabolic alterations in MLTC-1 Leydig cells responsive to low levels of PFOA exposure. The results showed that PFOA significantly regulated the expressions of 67 proteins and 17 metabolites, among which 18 proteins and 7 metabolites were specifically tied to lipid and fatty acid metabolism as well as testicular steroidogenesis. It is further suggested that low-dose PFOA stimulates steroid hormone synthesis by accelerating fatty acid metabolism and steroidogenic process, which is involved in the repression of p38 and cAMP-dependent ERK signaling pathway. The animal studies also revealed that environmentally relevant levels of PFOA increased serum steroid hormone levels accompanied by the activated cAMP and inhibited p38/ERK pathway in testis, which confirmed our in vitro findings. Overall, the present study will provide novel insights into the toxicological mechanisms of low-level PFOA-mediated steroidogenic disturbance, and may implicate the reproductive health risk of humans with environmental PFOA exposure.

Downregulation of SLC27A6 by DNA Hypermethylation Promotes Proliferation but Suppresses Metastasis of Nasopharyngeal Carcinoma Through Modulating Lipid Metabolism

Lipid is the building block and an important source of energy, contributing to the malignant behavior of tumor cells. Recent studies suggested that lipid droplets (LDs) accumulations were associated with nasopharyngeal carcinoma (NPC) progression. Solute carrier family 27 member 6 (SLC27A6) mediates the cellular uptake of long-chain fatty acid (LCFA), a necessary lipid component. However, the functions of SLC27A6 in NPC remain unknown. Here, we found a significant reduction of SLC27A6 mRNA in NPC tissues compared with normal nasopharyngeal epithelia (NNE). The promoter methylation ratio of SLC27A6 was greater in NPC than in non-cancerous tissues. The demethylation reagent 5-aza-2'-deoxycytidine (5-aza-dC) remarkably restored the mRNA expression of SLC27A6, suggesting that this gene was downregulated in NPC owing to DNA promoter hypermethylation. Furthermore, SLC27A6 overexpression level in NPC cell lines led to significant suppression of cell proliferation, clonogenicity in vitro, and tumorigenesis in vivo. Higher SLC27A6 expression, on the other hand, promoted NPC cell migration and invasion. In particular, re-expression of SLC27A6 faciliated epithelial-mesenchymal transition (EMT) signals in xenograft tumors. Furthermore, we observed that SLC27A6 enhanced the intracellular amount of triglyceride (TG) and total cholesterol (T-CHO) in NPC cells, contributing to lipid biosynthesis and increasing metastatic potential. Notably, the mRNA level of SLC27A6 was positively correlated with cancer stem cell (CSC) markers, CD24 and CD44. In summary, DNA promoter hypermethylation downregulated the expression of SLC27A6. Furthermore, re-expression of SLC27A6 inhibited the growth capacity of NPC cells but strengthened the CSC markers. Our findings revealed the dual role of SLC27A6 in NPC and shed novel light on the link between lipid metabolism and CSC maintenance.

Identification of a VHL gene mutation in atypical Von Hippel-Lindau syndrome: genotype-phenotype correlation and gene therapy perspective

Background

Classical von Hippel Lindau (VHL) disease/syndrome includes CNS hemangioblastoma, renal or pancreatic cysts, pheochromocytoma, renal carcinoma and exodermic cystadenoma. The syndrome is caused by mutation of VHL tumor suppressor gene. The most prevalent mutations are present in VHL syndrome. To date, > 500 mutations of gene related to the progression of VHL syndrome have been reported. VHL gene mutation presented in single lung or pancreatic tumor has been reported occasionally, but there is no report of both.

Methods

In this paper, we used CT scan, pathological and genetic examination methods to diagnose a rare atypical VHL syndrome.

Results

We reported a rare case of atypical VHL syndrome with authenticated VHL mutation at p.Arg167Gln, that was associated with not only bilateral pheochromocytoma but also lung carcinoid and neuroendocrine tumor of pancreas. Based on literature reviews, the patient was recommended to be further subjected to octreotide-based radionuclide therapy.

Conclusions

Combined with gene detection and clinical diagnosis, we found the inherent relationship between VHL genotype and phenotype, and constructed the standard diagnosis and treatment process of disease with rare VHL mutation from the perspective of gene therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02386-w.

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.

Epigenetic Inactivation of Acetyl-CoA Acetyltransferase 1 Promotes the Proliferation and Metastasis in Nasopharyngeal Carcinoma by Blocking Ketogenesis

The dysregulation of epigenetic modification and energy metabolism cooperatively contribute to the tumorigenesis of nasopharyngeal carcinoma (NPC). However, the detailed mechanisms underlying their joint contribution to NPC development and progression remain unclear. Here, we investigate the role of Acy1 Coenzyme A Acyltransferases1 (ACAT1), a key enzyme in the metabolic pathway of ketone bodies, in the proliferation and metastasis of NPC and to elucidate the underlying molecular mechanisms. Ketogenesis, plays a critical role in tumorigenesis. Previously, we reported two enzymes involved in ketone body metabolism mediate epigenetic silencing and act as tumor suppressor genes in NPC. Here, we identify another key enzyme, Acetyl-CoA acetyltransferase 1 (ACAT1), and show that its transcriptional inactivation in NPC is due to promoter hypermethylation. Ectopic overexpression of ACAT1 significantly suppressed the proliferation and colony formation of NPC cells in vitro. The migratory and invasive capacity of NPC cells was inhibited by ACAT1. The tumorigenesis of NPC cells overexpressing ACAT1 was decreased in vivo. Elevated ACAT1 in NPC cells was accompanied by an elevated expression of CDH1 and a reduced expression of vimentin and SPARC, strongly indicating that ACAT1 is involved in regulating epithelial-mesenchymal transition (EMT). We also found that ACAT1 contributes to increased intracellular levels of β-hydroxybutyrate (β-HB). Exogenously supplied β-HB significantly inhibits the growth of NPC cells in a dose-dependent manner. In summary, ACAT1 may function as a tumor suppressor via modulation of ketogenesis and could thus serve as a potential therapeutic target in NPC. In summary, our data suggest that regulation of ketogenesis may serve as adjuvant therapy in NPC.

The Aneugenicity of Ketone Bodies in Colon Epithelial Cells Is Mediated by Microtubule Hyperacetylation and Is Blocked by Resveratrol

Diabetes mellitus (DM) is considered to be associated with an increased risk of colorectal cancer. Recent studies have also revealed that tubulin hyperacetylation is caused by a diabetic status and we have reported previously that, under microtubule hyperacetylation, a microtubule severing protein, katanin-like (KL) 1, is upregulated and contributes to tumorigenesis. To further explore this phenomenon, we tested the effects of the ketone bodies, acetoacetate and β-hydroxybutyrate, in colon and fibroblast cells. Both induced microtubule hyperacetylation that responded differently to a histone deacetylase 3 knockdown. These two ketone bodies also generated intracellular reactive oxygen species (ROS) and hyperacetylation was commonly inhibited by ROS inhibitors. In a human fibroblast-based microtubule sensitivity test, only the KL1 human katanin family member showed activation by both ketone bodies. In primary cultured colon epithelial cells, these ketone bodies reduced the tau protein level and induced KL1- and α-tubulin acetyltransferase 1 (ATAT1)-dependent micronucleation. Resveratrol, known for its tumor preventive and tubulin deacetylation effects, inhibited this micronucleation. Our current data thus suggest that the microtubule hyperacetylation induced by ketone bodies may be a causal factor linking DM to colorectal carcinogenesis and may also represent an adverse effect of them that needs to be controlled if they are used as therapeutics.

SDHB Suppresses the Tumorigenesis and Development of ccRCC by Inhibiting Glycolysis

Metabolic reprogramming is the prominent feature of clear cell renal cell carcinoma (ccRCC). Succinate dehydrogenase subunit B (SDHB) is one of subunits of mitochondrial respiratory chain complex II. The loss of SDHB function is closely related with metabolic changes in kidney cancer cells. However, the role and molecular mechanism of SDHB in ccRCC occurrence and progression are still unclear. In this study, the results of bioinformatics analyses on GEO, TCGA and oncomine databases and immunohistochemistry showed that the expression level of SDHB was downregulated in ccRCC tissues. SDHB level was gradually downregulated as ccRCC stage and grade progressed. The low level of SDHB was associated with poor prognosis of ccRCC patients, especially for advanced ccRCC patients. Increased methylation levels in SDHB gene promoter led to the downregulation of SDHB level in ccRCC tissues. SDHB was correlated with many metabolism related genes and its interacting proteins were enriched in metabolic pathways. SDHB overexpression suppressed the proliferation, colony formation and migration of ccRCC cells by inhibiting aerobic glycolysis. SDHB may be a potential prognostic marker and therapeutic target for ccRCC.

The Role of Pi, Glutamine and the Essential Amino Acids in Modulating the Metabolism in Diabetes and Cancer

Purpose

Re-examine the current metabolic models.

Methods

Review of literature and gene networks.

Results

Insulin activates Pi uptake, glutamine metabolism to stabilise lipid membranes. Tissue turnover maintains the metabolic health. Current model of intermediary metabolism (IM) suggests glucose is the source of energy, and anaplerotic entry of fatty acids and amino acids into mitochondria increases the oxidative capacity of the TCA cycle to produce the energy (ATP). The reduced cofactors, NADH and FADH2, have different roles in regulating the oxidation of nutrients, membrane potentials and biosynthesis. Trans-hydrogenation of NADH to NADPH activates the biosynthesis. FADH2 sustains the membrane potential during the cell transformations. Glycolytic enzymes assume the non-canonical moonlighting functions, enter the nucleus to remodel the genetic programmes to affect the tissue turnover for efficient use of nutrients. Glycosylation of the CD98 (4F2HC) stabilises the nutrient transporters and regulates the entry of cysteine, glutamine and BCAA into the cells. A reciprocal relationship between the leucine and glutamine entry into cells regulates the cholesterol and fatty acid synthesis and homeostasis in cells. Insulin promotes the Pi transport from the blood to tissues, activates the mitochondrial respiratory activity, and glutamine metabolism, which activates the synthesis of cholesterol and the de novo fatty acids for reorganising and stabilising the lipid membranes for nutrient transport and signal transduction in response to fluctuations in the microenvironmental cues. Fatty acids provide the lipid metabolites, activate the second messengers and protein kinases. Insulin resistance suppresses the lipid raft formation and the mitotic slippage activates the fibrosis and slow death pathways.

Expression and Prognostic Significance of Cadherin 4 (CDH4) in Renal Cell Carcinoma

Background

Aberrant expression of cadherin family members and their possible biological function have been widely studied in renal cell carcinoma (RCC). However, the expression of cadherin 4 (CDH4) and its value in RCC diagnosis and prognosis remains elusive.

Material/Methods

The TCGA database was used to analyze the expression of CDH4 and its clinical parameters and prognosis in 891 RCC patients. In addition, real-time PCR was used to verify the transcription of CDH4 in renal clear cell carcinoma tissue, and the distribution of protein was observed by immunohistochemical staining.

Results

We found that the mRNA level of CDH4 was elevated in primary RCC in contrast with normal kidney samples using bioinformatics analysis based on the TCGA database. Among the 3 main subtypes of RCC, transcriptional CDH4 was significantly increased in KIRC and KIRP, while it was downregulated in KICH. Interestingly, CDH4 mRNA gradually decreased with the progression of KIRC and KIRP. The transcription of CDH4 in the primary tumor of KIRP patients at T3–T4 stages and KIRC patients with lymph node and distant metastasis were decreased significantly. Overall survival (OS) showed that KIRC and KICH patients with lower expression of CDH4 had worse outcomes.

Conclusions

The transcriptional level of CDH4 may serve as an effective diagnostic and prognostic biomarker for RCC patients.

Genome-Scale Metabolic Modeling with Protein Expressions of Normal and Cancerous Colorectal Tissues for Oncogene Inference

Although cancer has historically been regarded as a cell proliferation disorder, it has recently been considered a metabolic disease. The first discovery of metabolic alterations in cancer cells refers to Otto Warburg’s observations. Cancer metabolism results in alterations in metabolic fluxes that are evident in cancer cells compared with most normal tissue cells. This study applied protein expressions of normal and cancer cells to reconstruct two tissue-specific genome-scale metabolic models. Both models were employed in a tri-level optimization framework to infer oncogenes. Moreover, this study also introduced enzyme pseudo-coding numbers in the gene association expression to avoid performing posterior decision-making that is necessary for the reaction-based method. Colorectal cancer (CRC) was the topic of this case study, and 20 top-ranked oncogenes were determined. Notably, these dysregulated genes were involved in various metabolic subsystems and compartments. We found that the average similarity ratio for each dysregulation is higher than 98%, and the extent of similarity for flux changes is higher than 93%. On the basis of surveys of PubMed and GeneCards, these oncogenes were also investigated in various carcinomas and diseases. Most dysregulated genes connect to catalase that acts as a hub and connects protein signaling pathways, such as those involving TP53, mTOR, AKT1, MAPK1, EGFR, MYC, CDK8, and RAS family.

Dysregulation of Ketone Body Metabolism Is Associated With Poor Prognosis for Clear Cell Renal Cell Carcinoma Patients

Kidney is an important organ for ketone body metabolism. However, the role of abnormal ketone metabolism and its possible function in tumorigenesis of clear cell renal cell carcinoma (ccRCC) have not yet been elucidated. Three differentially expressed key enzymes involved in ketone body metabolism, ACAT1, BDH2, and HMGCL, were screened out between ccRCC and normal kidney tissues using the GEO and TCGA databases.We confirmed that the transcription and protein expression of ACAT1, BDH2, and HMGCL were significantly lower in ccRCC by real-time RT-PCR and IHC assays. Those patients with lower expression of these three genes have a worse outcome. In addition, we demonstrated that ectopic expression of each of these genes inhibited the proliferation of ccRCC cells. The overexpressed ACAT1 and BDH2 genes remarkably impeded the migratory and invasive capacity of ccRCC cells. Furthermore, exogenous β-hydroxybutyrate suppressed the growth of ccRCC cells in vitro in a dose-dependent manner. Our findings suggest that ACAT1, BDH2, and HMGCL are potential tumor suppressor genes, and constitute effective prognostic biomarkers for ccRCC. Ketone body metabolism might thus be a promising target in a process for developing novel therapeutic approaches to treat ccRCC.

Inactivation of 3-hydroxybutyrate dehydrogenase type 2 promotes proliferation and metastasis of nasopharyngeal carcinoma by iron retention

Background

3-Hydroxybutyrate dehydrogenase type 2 (BDH2) is known to catalyse a rate-limiting step in the biogenesis of the mammalian siderophore and regulate intracellular iron metabolism. Here we aim to explore the expression and possible function of BDH2 in nasopharyngeal carcinoma (NPC).

Methods

The transcription and protein expression of BDH2 in NPC were determined by both real-time RT-PCR and immunohistochemistry staining assays. Cell proliferation, migration and invasion were evaluated by MTT assay, wound-healing assay and Transwell assay, respectively. The profile of genes regulated by restoring BDH2 expression in NPC cells was analysed by cDNA microarray. The level of iron in NPC cells was detected by iron colorimetric assay.

Results

The expression of BDH2 was significantly downregulated in NPC. Ectopic expression of BDH2 inhibited NPC cell proliferation and colony formation. Meanwhile, BDH2 suppressed the migration and invasion of NPC cells by reversing the epithelial–mesenchymal transition (EMT). In addition, a higher level of BDH2 decreased the growth and metastasis of NPC cells via reducing intracellular iron level.

Conclusions

Our findings suggest that BDH2 may be a candidate tumour-suppressor gene in NPC. Decreasing intracellular iron could be an effective therapeutic approach for NPC.

More Than One HMG-CoA Lyase: The Classical Mitochondrial Enzyme Plus the Peroxisomal and the Cytosolic Ones

There are three human enzymes with HMG-CoA lyase activity that are able to synthesize ketone bodies in different subcellular compartments. The mitochondrial HMG-CoA lyase was the first to be described, and catalyzes the cleavage of 3-hydroxy-3-methylglutaryl CoA to acetoacetate and acetyl-CoA, the common final step in ketogenesis and leucine catabolism. This protein is mainly expressed in the liver and its function is metabolic, since it produces ketone bodies as energetic fuels when glucose levels are low. Another isoform is encoded by the same gene for the mitochondrial HMG-CoA lyase (HMGCL), but it is located in peroxisomes. The last HMG-CoA lyase to be described is encoded by a different gene, HMGCLL1, and is located in the cytosolic side of the endoplasmic reticulum membrane. Some activity assays and tissue distribution of this enzyme have shown the brain and lung as key tissues for studying its function. Although the roles of the peroxisomal and cytosolic HMG-CoA lyases remain unknown, recent studies highlight the role of ketone bodies in metabolic remodeling, homeostasis, and signaling, providing new insights into the molecular and cellular function of these enzymes.

Implications of Gene Inheritance Patterns on the Heterosis of Abdominal Fat Deposition in Chickens

Heterosis, a phenomenon characterized by the superior performance of hybrid individuals relative to their parents, has been widely utilized in livestock and crop breeding, while the underlying genetic basis remains elusive in chickens. Here, we performed a reciprocal crossing experiment with broiler and layer chickens and conducted RNA sequencing on liver tissues for reciprocal crosses and their parental lines to identify inheritance patterns of gene expression. Our results showed that heterosis of the abdominal fat percentage was 69.28%–154.71% in reciprocal crosses. Over-dominant genes of reciprocal crosses were significantly enriched in three biological pathways, namely, butanoate metabolism, the synthesis and degradation of ketone bodies, and valine, leucine, and isoleucine degradation. Among these shared over-dominant genes, we found that a lipid-related gene, HMGCL, was enriched in these pathways. Furthermore, we validated this gene as over-dominant using qRT-PCR. Although no shared significant pathway was detected in the high-parent dominant genes of reciprocal crosses, high-parent dominant gene expression was the major gene inheritance pattern in reciprocal crosses and we could not exclude the effect of high-parent dominant genes. These findings suggest that non-additive genes play important roles in the heterosis of important traits in chickens and have important implications regarding our understanding of heterosis.

FOXF2 differentially regulates expression of metabolic genes in non-cancerous and cancerous breast epithelial cells

Forkhead box F2 (FOXF2) functions as a transcription factor and is critically involved in programming organogenesis and regulating epithelial-to-mesenchymal transition (EMT) and cell proliferation. We recently have revealed that FOXF2 can exert distinct functional effects on different molecular subtypes of breast cancer. We found that FOXF2 expression is epigenetically silenced in luminal breast cancers due to its tumor-suppressive role in DNA replication regulation. In contrast, FOXF2 is overexpressed in basal-like triple-negative breast cancers (TNBCs) due to its oncogenic role in promoting EMT. Although our and other studies have shown that FOXF2 dysregulation is critical for tumorigenesis of various tissue types, the role of FOXF2 in metabolic rewiring of cancer remains unknown. In this study, we analyzed our previous microarray data to understand the metabolic role of FOXF2 in non-cancerous and cancerous breast epithelial cells. Our studies showed that in non-cancerous breast epithelial cells FOXF2 can also play a dual role either in tumor suppression or in tumor promotion through regulating expression of tumor-suppressive and oncogenic metabolic genes. Furthermore, we found that FOXF2-regulated metabolic genes are not conserved between non-cancerous and cancerous breast epithelial cells and FOXF2 is involved in metabolic rewiring in breast cancer cells. This is the first report to explore the metabolic function of FOXF2 in breast cancer.