Pan-cancer analysis reveals the oncogenic role of 3-hydroxy-3-methylglutaryl-CoA synthase 1

[Inhibition of Lung Squamous Cancer Target HMGCS1 Promotes Cellular Ferroptosis]

BACKGROUND

Targeted therapies are ineffective in lung squamous cancer (LUSC), and the low response rate of immunotherapy hampers its application in LUSC, so it is urgent to explore new strategies for LUSC treatment. Ferroptosis plays an important role in tumour suppression. The aim of this study was to investigate the role and mechanism of targeting 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) in regulating ferroptosis in LUSC cells, in order to provide a new research direction for LUSC therapy.

METHODS

The expression of HMGCS1 in LUSC was analysed by The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) online databases; the relationship between HMGCS1 and survival time of lung cancer was analysed by the Kaplan-Meier Plotter online survival database; the expression level of HMGCS1 in LUSC tissues was verified by immunohistochemistry. After interfering with HMGCS1 expression by small interfering RNA (siRNA), cell activity and cell migration ability were detected by CCK8 and Transwell assay; apoptosis was detected by flow cytometry after interfering with HMGCS1 or after treatment with the HMGCS1 inhibitor of hymeglusin; Fe2+, reactive oxygen species (ROS) and lipid peroxidation levels were detected by flow cytometry and high-content confocal fluorescence imaging systems, respectively in SKMES cells after inhibition of HMGCS1; and Western blot was performed to detect the expression of ACSL4, GPX4 and SLC7A11, which are markers of the ferroptosis pathway after inhibition of HMGCS1.

RESULTS

HMGCS1 mRNA and protein levels were significantly high in LUSC; siRNA interference with HMGCS1 expression inhibited the proliferative activity and migration ability of LUSC cells, but had no significant effect on apoptosis. Interference with HMGCS1 or treatment with the HMGCS1 inhibitor of hymeglusin significantly promoted intracellular Fe2+, ROS and lipid peroxidation levels in SKMES cells, and induced ferroptosis in LUSC cells; Western blot assay showed that inhibition of HMGCS1 significantly promoted the expression of ACSL4.

CONCLUSIONS

Inhibition of HMGCS1, a target of LUSC, promotes ferroptosis in lung cancer cells and provides a research basis for screening new therapeutic targets for LUSC.

Metabolic Contrasts: Fatty Acid Oxidation and Ketone Bodies in Healthy Brains vs. Glioblastoma Multiforme

The metabolism of glucose and lipids plays a crucial role in the normal homeostasis of the body. Although glucose is the main energy substrate, in its absence, lipid metabolism becomes the primary source of energy. The main means of fatty acid oxidation (FAO) takes place in the mitochondrial matrix through β-oxidation. Glioblastoma (GBM) is the most common form of primary malignant brain tumor (45.6%), with an incidence of 3.1 per 100,000. The metabolic changes found in GBM cells and in the surrounding microenvironment are associated with proliferation, migration, and resistance to treatment. Tumor cells show a remodeling of metabolism with the use of glycolysis at the expense of oxidative phosphorylation (OXPHOS), known as the Warburg effect. Specialized fatty acids (FAs) transporters such as FAT, FABP, or FATP from the tumor microenvironment are overexpressed in GBM and contribute to the absorption and storage of an increased amount of lipids that will provide sufficient energy used for tumor growth and invasion. This review provides an overview of the key enzymes, transporters, and main regulatory pathways of FAs and ketone bodies (KBs) in normal versus GBM cells, highlighting the need to develop new therapeutic strategies to improve treatment efficacy in patients with GBM.

Cholesterol Metabolism in Pancreatic Cancer

Pancreatic cancer's substantial impact on cancer-related mortality, responsible for 8% of cancer deaths and ranking fourth in the US, persists despite advancements, with a five-year relative survival rate of only 11%. Forecasts predict a 70% surge in new cases and a 72% increase in global pancreatic cancer-related deaths by 2040. This review explores the intrinsic metabolic reprogramming of pancreatic cancer, focusing on the mevalonate pathway, including cholesterol biosynthesis, transportation, targeting strategies, and clinical studies. The mevalonate pathway, central to cellular metabolism, significantly shapes pancreatic cancer progression. Acetyl coenzyme A (Acetyl-CoA) serves a dual role in fatty acid and cholesterol biosynthesis, fueling acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) development. Enzymes, including acetoacetyl-CoA thiolase, 3-hydroxy-3methylglutaryl-CoA (HMG-CoA) synthase, and HMG-CoA reductase, are key enzymes in pancreatic cancer. Inhibiting HMG-CoA reductase, e.g., by using statins, shows promise in delaying PanIN progression and impeding pancreatic cancer. Dysregulation of cholesterol modification, uptake, and transport significantly impacts tumor progression, with Sterol O-acyltransferase 1 (SOAT1) driving cholesterol ester (CE) accumulation and disrupted low-density lipoprotein receptor (LDLR) expression contributing to cancer recurrence. Apolipoprotein E (ApoE) expression in tumor stroma influences immune suppression. Clinical trials targeting cholesterol metabolism, including statins and SOAT1 inhibitors, exhibit potential anti-tumor effects, and combination therapies enhance efficacy. This review provides insights into cholesterol metabolism's convergence with pancreatic cancer, shedding light on therapeutic avenues and ongoing clinical investigations.

Effects of µ-Conotoxin GIIIB on the cellular activity of mouse skeletal musculoblast: combined transcriptome and proteome analysis

µ-Conotoxin GIIIB (µ-CTX GIIIB) is a polypeptide containing three disulfide bridges, produced by the sea snail Conus geographus. This study was aimed to explored the cytotoxic effects of µ-CTX GIIIB on mouse skeletal musculoblast (Sol8). Sol8 cells were exposed to ouabain and veratridine to establish the cell injury model, and then treated with µ-CTX GIIIB. CCK-8 was adopted to evaluate the cytotoxicity of µ-CTX GIIIB. Then, proteomics and transcriptome were conducted, and the explore the differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) affected by µ-CTX GIIIB were found. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was used to investigate the affected signaling pathways. µ-CTX GIIIB increased the cell survival rate of injured Sol8 cells. We found and identified 1,663 DEGs and 444 DEPs influenced by µ-CTX GIIIB. 106 pairs of correlated DEGs and DEPs were selected by combining transcriptome and proteome data. The results of KEGG and GO analysis showed that µ-CTX GIIB affected the cell cycle, apoptosis, DNA damage and repair, lipid metabolism and other biological processes of Sol8 cells. µ-CTX GIIIB could affected cell cycle regulation, DNA damage repair, and activation of tumor factors, with potential carcinogenic effects. Our results provide an important basis for the study of in vitro toxicity, the mechanism of toxicity and injury prevention by µ-CTX GIIIB.

VIM‑AS1 promotes proliferation and drives enzalutamide resistance in prostate cancer via IGF2BP2‑mediated HMGCS1 mRNA stabilization

VIM‑AS1, a cancer‑specific long non‑coding RNA, has been recognized as a pivotal regulator in multiple types of cancer. However, the role of VIM‑AS1 in the proliferation and resistance to anti‑androgen therapy of LNCaP and C4‑2 prostate cancer cells remains to be determined. In the current study, gain‑and‑loss experiments were used to investigate the effects of VIM‑AS on the proliferation and anti‑androgen therapy of LNCaP and C4‑2 cells. RNA sequencing, RNA pulldown and RNA immunoprecipitation were used to elucidate the underlying mechanism of VIM‑AS1 driving prostate progression. It was demonstrated that VIM‑AS1 was upregulated in C4‑2 cells, an established castration‑resistant prostate cancer (CRPC) cell line, compared with in LNCaP cells, an established hormone‑sensitive prostate cancer cell line. The present study further demonstrated that VIM‑AS1 was positively associated with the clinical stage of prostate cancer. Functionally, overexpression of VIM‑AS1 decreased the sensitivity to enzalutamide treatment and enhanced the proliferation of LNCaP cells in vitro, whereas knockdown of VIM‑AS1 increased the sensitivity to enzalutamide treatment and reduced the proliferation of C4‑2 cells in vitro and in vivo. Mechanistically, 3‑hydroxy‑3‑methylglutaryl‑CoA synthase 1 (HMGCS1) was identified as one of the direct downstream targets of VIM‑AS1, and VIM‑AS1 promoted HMGCS1 expression by enhancing HMGCS1 mRNA stability through a VIM‑AS1/insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2)/HMGCS1 RNA‑protein complex. Rescue assays indicated that knockdown of HMGCS1 expression ameliorated the increase in proliferation and enzalutamide resistance of prostate cancer cells induced by VIM‑AS1 overexpression. Overall, the present study determined the roles and mechanism of the VIM‑AS1/IGF2BP2/HMGCS1 axis in regulating proliferation and enzalutamide sensitivity of prostate cancer cells and suggested that VIM‑AS1 may serve as a novel therapeutic target for the treatment of patients with CRPC.

Antidiabetic drug metformin suppresses tumorigenesis through inhibition of mevalonate pathway enzyme HMGCS1

Metformin, an antidiabetic drug, shows some potent antitumor effects. However, the molecular mechanism of metformin in tumor suppression has not been clarified. Here, we provided evidence using in vitro and in vivo data that metformin inhibited mevalonate pathway by downregulation of 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1), a key enzyme in this pathway. Our results further demonstrated that metformin downregulated HMGCS1 expression through inhibition of transcription factor nuclear factor E2-related factor 2. In addition, we determined that HMGCS1 was highly expressed in human liver and lung cancer tissues and associated with lower survival rates. In summary, our study indicated that metformin suppresses tumorigenesis through inhibition of the nuclear factor E2-related factor 2-HMGCS1 axis, which might be a potential target in cancer prevention and treatment.

Knockout of Nur77 Leads to Amino Acid, Lipid, and Glucose Metabolism Disorders in Zebrafish

Orphan nuclear receptor Nur77 has been reported to be implicated in a diverse range of metabolic processes, including carbohydrate metabolism and lipid metabolism. However, the detailed mechanism of Nur77 in the regulation of metabolic pathway still needs to be further investigated. In this study, we created a global nur77 knockout zebrafish model by CRISPR/Cas9 technique, and then performed whole-organism RNA sequencing analysis in wildtype and nur77-deficient zebrafish to dissect the genetic changes in metabolic-related pathways. We found that many genes involved in amino acid, lipid, and carbohydrate metabolism changed by more than twofold. Furthermore, we revealed that nur77^-/- mutant displayed increased total cholesterol (TC) and triglyceride (TG), alteration in total amino acids, as well as elevated glucose. We also demonstrated that the elevated glucose was not due to the change of glucose uptake but was likely caused by the disorder of glycolysis/gluconeogenesis and the impaired β-cell function, including downregulated insb expression, reduced β-cell mass, and suppressed insulin secretion. Importantly, we also verified that targeted expression of Nur77 in the β cells is sufficient to rescue the β-cell defects in global nur77^-/- larvae zebrafish. These results provide new information about the global metabolic network that Nur77 signaling regulates, as well as the role of Nur77 in β-cell function.