Decreased HMGCS1 inhibits proliferation and inflammatory response of keratinocytes and ameliorates imiquimod-induced psoriasis via the STAT3/IL-23 axis

Psoriasis is an immuno-inflammatory disease characterized by excessive keratinocyte proliferation, requiring extensive lipids. 3-hydroxy-3-methylglutaryl-coenzyme A synthase 1 (HMGCS1) is an essential enzyme in the mevalonate pathway, involved in cholesterol synthesis and the inflammatory response. However, the role of HMGCS1 in psoriasis has remained elusive. This study aims to elucidate the mechanism by which HMGCS1 controls psoriasiform inflammation. We discovered an increased abundance of HMGCS1 in psoriatic lesions when analyzing two Gene Expression Omnibus (GEO) datasets and confirmed this in psoriatic animal models and psoriatic patients by immunohistochemistry. In a TNF-α stimulated psoriatic HaCaT cell line, HMGCS1 was found to be overexpressed. Knockdown of HMGCS1 using siRNA suppressed the migration and proliferation of HaCaT cells. Mechanistically, HMGCS1 downregulation also reduced the expression of IL-23 and the STAT3 phosphorylation level. In imiquimod-induced psoriatic mice, intradermal injection of HMGCS1 siRNA significantly decreased the expression of HMGCS1 in the epidermis, which in turn led to an improvement in the Psoriasis Area and Severity Index score, epidermal thickening, and pathological Baker score. Additionally, expression levels of inflammatory cytokines IL-23, IL1-β, chemokine CXCL1, and innate immune mediator S100A7-9 were downregulated in the epidermis. In conclusion, HMGCS1 downregulation improved psoriasis in vitro and in vivo through the STAT3/IL-23 axis.

Hypoxia upregulating ACSS2 enhances lipid metabolism reprogramming through HMGCS1 mediated PI3K/AKT/mTOR pathway to promote the progression of pancreatic neuroendocrine neoplasms

BACKGROUND

Pancreatic neuroendocrine neoplasms (pNENs) are relatively rare. Hypoxia and lipid metabolism-related gene acetyl-CoA synthetase 2 (ACSS2) is involved in tumor progression, but its role in pNENs is not revealed. This study showed that hypoxia can upregulate ACSS2, which plays an important role in the occurrence and development of pNENs through lipid metabolism reprogramming. However, the precise role and mechanisms of ACSS2 in pNENs remain unknown.

METHODS

mRNA and protein levels of ACSS2 and 3-hydroxy-3-methylglutaryl-CoA synthase1 (HMGCS1) were detected using quantitative real-time PCR (qRT-PCR) and Western blotting (WB). The effects of ACSS2 and HMGCS1 on cell proliferation were examined using CCK-8, colony formation assay and EdU assay, and their effects on cell migration and invasion were examined using transwell assay. The interaction between ACSS2 and HMGCS1 was verified by Co-immunoprecipitation (Co-IP) experiments, and the functions of ACSS2 and HMGCS1 in vivo were determined by nude mouse xenografts.

RESULTS

We demonstrated that hypoxia can upregulate ACSS2 while hypoxia also promoted the progression of pNENs. ACSS2 was significantly upregulated in pNENs, and overexpression of ACSS2 promoted the progression of pNENs and knockdown of ACSS2 and ACSS2 inhibitor (ACSS2i) treatment inhibited the progression of pNENs. ACSS2 regulated lipid reprogramming and the PI3K/AKT/mTOR pathway in pNENs, and ACSS2 regulated lipid metabolism reprogramming through the PI3K/AKT/mTOR pathway. Co-IP experiments indicated that HMGCS1 interacted with ACSS2 in pNENs. Overexpression of HMGCS1 can reverse the enhanced lipid metabolism reprogramming and tumor-promoting effects of knockdown of ACSS2. Moreover, overexpression of HMGCS1 reversed the inhibitory effect of knockdown of ACSS2 on the PI3K/AKT/mTOR pathway.

CONCLUSION

Our study revealed that hypoxia can upregulate the lipid metabolism-related gene ACSS2, which plays a tumorigenic effect by regulating lipid metabolism through activating the PI3K/AKT/mTOR pathway. In addition, HMGCS1 can reverse the oncogenic effects of ACSS2, providing a new option for therapeutic strategy.

Ligustilide covalently binds to Cys129 of HMGCS1 to ameliorate dyslipidemia

Dyslipidemia is characterized by elevated levels of total cholesterol and triglycerides in serum, and has become the primary human health killer because of the major risk factors for cardiovascular diseases. Although there exist plenty of drugs for dyslipidemia, the number of patients who could benefit from lipid-lowering drugs still remains a concern. Ligustilide (Lig), a natural phthalide derivative, was reported to regulate lipid metabolic disorders. However, its specific targets and underlying molecular mechanism are still unclear. In this study, we found that Lig alleviated high fat diet-induced dyslipidemia by inhibiting cholesterol biosynthesis. Furthermore, a series of chemical biological analysis methods were used to identify its target protein for regulating lipid metabolism. Collectively, 3-hydroxy-3-methylglutaryl coenzyme A synthetase 1 (HMGCS1) of hepatic cells was identified as a target for Lig to regulate lipid metabolism. The mechanistic study confirmed that Lig irreversibly binds to Cys129 of HMGCS1 via its metabolic intermediate 6,7-epoxyligustilide, thereby reducing cholesterol synthesis and improving lipid metabolism disorders. These findings not only systematically elucidated the lipid-lowering mechanism of Lig, but also provided a new structural compound for the treatment of dyslipidemia.

Gypenosides suppress hepatocellular carcinoma cells by blocking cholesterol biosynthesis through inhibition of MVA pathway enzyme HMGCS1

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high morbidity and mortality. Targeting abnormal cholesterol metabolism is a potential therapeutic direction. Therefore, more natural drugs targeting cholesterol in HCC need to be developed. Gypenosides (Gyp), the major constituent of Gynostemma pentaphyllum, has been demonstrated to have pharmacological properties on anti-cancer, anti-obesity, and hepatoprotective. We investigated whether Gyp, isolated and purified by our lab, could inhibit HCC progression by inhibiting cholesterol synthesis. The present research showed that Gyp inhibited proliferation and migration, and induced apoptosis in Huh-7 and Hep3B cells. Metabolomics, transcriptomics, and target prediction all suggested that lipid metabolism and cholesterol biosynthesis were the mechanisms of Gyp. Gyp could limit the production of cholesterol and target HMGCS1, the cholesterol synthesis-related protein. Downregulation of HMGCS1 could suppress the progression and abnormal cholesterol metabolism of HCC. In terms of mechanism, Gyp suppressed mevalonate (MVA) pathway mediated cholesterol synthesis by inhibiting HMGCS1 transcription factor SREBP2. And the high expression of HMGCS1 in HCC human specimens was correlated with poor clinical prognosis. The data suggested that Gyp could be a promising cholesterol-lowering drug for the prevention and treatment of HCC. And targeting SREBP2-HMGCS1 axis in MVA pathway might be an effective HCC therapeutic strategy.

P4HA1 activates HMGCS1 to promote nasopharyngeal carcinoma ferroptosis resistance and progression

Ferroptosis is a novel type of iron-dependent regulatory cell death. To date, the regulatory mechanism of ferroptosis in nasopharyngeal carcinoma (NPC) remains poorly understood. In this study, we found that the prolyl 4-hydroxylase (P4H) subunit P4HA1 protects NPC cells from erastin-induced ferroptosis by activating HMGCS1, a key enzyme in the mevalonate pathway. We also found that the P4HA1/HMGCS1 axis promoted NPC cell proliferation in vitro. In vivo, downregulation of the P4HA1/HMGCS1 axis inhibited the growth of NPC cell xenografts and enhanced the inhibitory effect of erastin on tumor growth. Extracellular matrix (ECM) detachment is an important trigger for ferroptosis. We found that the P4HA1/HMGCS1 axis promoted the ferroptosis resistance and survival of ECM-detached NPC cells. In vivo, downregulation of the P4HA1/HMGCS1 axis inhibited the lung colonization of NPC cells and enhanced the inhibitory effect of erastin on NPC lung metastasis. Moreover, the high expression of P4HA1 predicted a poor prognosis and served as a potential independent prognostic factor in patients with NPC. In conclusion, P4HA1 is a novel molecular marker of NPC ferroptosis resistance and a poor prognosis, and the P4HA1/HMGCS1 axis provides a new target for the treatment of NPC progression.

ERRα Up-Regulates Invadopodia Formation by Targeting HMGCS1 to Promote Endometrial Cancer Invasion and Metastasis

Estrogen-related receptor alpha (ERRα) plays an important role in endometrial cancer (EC) progression. However, the biological roles of ERRα in EC invasion and metastasis are not clear. This study aimed to investigate the role of ERRα and 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) in regulating intracellular cholesterol metabolism to promote EC progression. ERRα and HMGCS1 interactions were detected by co-immunoprecipitation, and the effects of ERRα/HMGCS1 on the metastasis of EC were investigated by wound-healing and transwell chamber invasion assays. Cellular cholesterol content was measured to verify the relationship between ERRα and cellular cholesterol metabolism. Additionally, immunohistochemistry was performed to confirm that ERRα and HMGCS1 were related to EC progression. Furthermore, the mechanism was investigated using loss-of-function and gain-of-function assays or treatment with simvastatin. High expression levels of ERRα and HMGCS1 promoted intracellular cholesterol metabolism for invadopodia formation. Moreover, inhibiting ERRα and HMGCS1 expression significantly weakened the malignant progression of EC in vitro and in vivo. Our functional analysis showed that ERRα promoted EC invasion and metastasis through the HMGCS1-mediated intracellular cholesterol metabolism pathway, which was dependent on the epithelial-mesenchymal transition pathway. Our findings suggest that ERRα and HMGCS1 are potential targets to suppress EC progression.

Krüppel-like Factor 13 Promotes HCC Progression by Transcriptional Regulation of HMGCS1-mediated Cholesterol Synthesis

BACKGROUND AND AIMS

Krüppel-like factor (KLF) has a role in the occurrence, development and metabolism of cancer. We aimed to explore the role and potential molecular mechanism of KLF13 in the growth and migration of liver cancer cells.

METHODS

The expression of KLF13 in hepatocellular carcinoma (HCC) tissues was higher than that in normal tissues according to analysis of The Cancer Genome Atlas (TCGA) database. Lentiviral plasmids were used for overexpression and plasmid knockdown of KLF13. Real-time quantitative polymerase chain reaction (qPCR) and western blotting were used to detect mRNA and protein expression in HCC tissues and cells. Cell counting kit-8 (CCK-8), colony formation, cell migration and invasion, and flow cytometry assays were used to assess the in vitro function of KLF13 in HCC cells. The effect of KLF13 on xenograft tumor growth in vivo was evaluated. The cholesterol content of HCC cells was determined by an indicator kit. A dual-luciferase reporter assay and chromatin immunoprecipitation sequencing (ChIP-seq) revealed the binding relationship between KLF13 and HMGCS1.

RESULTS

The expression of KLF13 was upregulated in HCC tissues and TCGA database. KLF13 knockdown inhibited the proliferation, migration and invasion of HepG2 and Huh7 cells and increased the apoptosis of Huh7 cells. The opposite effects were observed with the overexpression of KLF13 in SK-Hep1 and MHCC-97H cells. The overexpression of KLF13 promoted the growth of HCC in nude mice and KLF13 transcription promoted the expression of HMGCS1 and the biosynthesis of cholesterol. KLF13 knockdown inhibited cholesterol biosynthesis mediated by HMGCS1 and inhibited the growth and metastasis of HCC cells.

CONCLUSIONS

KLF13 acted as a tumor promoter in HCC by positively regulating HMGCS1-mediated cholesterol biosynthesis.

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.

Ursolic acid inhibits the cholesterol biosynthesis and alleviates high fat diet-induced hypercholesterolemia via irreversible inhibition of HMGCS1 in vivo

BACKGROUND

In hypercholesteremia, the concentrations of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are enhanced in serum, which is strongly associated with an increased risk of developing atherosclerosis. Ursolic acid (UA), a pentacyclic terpenoid carboxylic acid, was found to alleviate hypercholesterolemia and hypercholesterolemia-induced cardiovascular disease. However, the specific targets and molecular mechanisms related to the effects of UA in reducing cholesterol have not been elucidated.

PURPOSE

In this study, we aimed to illustrate the target of UA in the treatment of hypercholesterolemia and to reveal its underlying molecular mechanism.

METHODS

Nontargeted metabolomics was conducted to analyze the metabolites and related pathways that UA affected in vivo. The main lipid metabolism targets of UA were analyzed by target fishing and fluorescence colocalization in mouse liver. Molecular docking, in-gel fluorescence scan and thermal shift were assessed to further investigate the binding site of the UA metabolite with HMGCS1. C57BL/6 mice were fed a high-fat diet (HFD) for 12 weeks to induce hypercholesteremia. Liver tissues were used to verify the cholesterol-lowering molecular mechanism of UA by targeted metabolomics, serum was used to detect biochemical indices, and the entire aorta was used to analyze the formation of atherosclerotic lesions.

RESULTS

Our results showed that hydroxy‑3-methylglutaryl coenzyme A synthetase 1 (HMGCS1) was the primary lipid metabolism target protein of UA. The UA metabolite epoxy-modified UA irreversibly bonds with the thiol of Cys-129 in HMGCS1, which inhibits the catalytic activity of HMGCS1 and reduces the generation of precursors in cholesterol biosynthesis in vivo. The contents of TC and LDL-C in serum and the formation of the atherosclerotic area in the entire aorta were markedly reduced with UA treatment in Diet-induced hypercholesteremia mice.

CONCLUSION

UA inhibits the catalytic activity of HMGCS1, reduces the generation of downstream metabolites in the process of cholesterol biosynthesis and alleviates Diet-induced hypercholesteremia via irreversible binding with HMGCS1 in vivo. It is the first time to clarify the irreversible inhibition mechanism of UA against HMGCS1. This paper provides an increased understanding of UA, particularly regarding the molecular mechanism of the cholesterol-lowering effect, and demonstrates the potential of UA as a novel therapeutic for the treatment of hypercholesteremia.

Hymeglusin Enhances the Pro-Apoptotic Effects of Venetoclax in Acute Myeloid Leukemia

Venetoclax is used for the priority treatment of elderly patients with acute myeloid leukemia (AML). Resistance or intolerance to venetoclax offsets its clinical benefits in some patients. Combination strategies with other drugs are promising alternatives to overcome the current complications associated with venetoclax use. Hymeglusin, a specific inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A synthase 1 (HMGCS1), regulates the mevalonate pathway, which is vital for AML growth and chemosensitivity. The effects of the combination of venetoclax and hymeglusin on AML were explored in this study. The correlations between HMGCS1 and apoptosis-related genes were analyzed using the Gene Expression Profiling Interactive Analysis 2 and The Cancer Genome Atlas databases. Apoptosis and cell viability were detected in HL-60 and KG-1 cells after treatment with gradient concentrations of venetoclax or hymeglusin. The transcriptomic profiles of HL-60 and KG-1 cells were compared via RNA-Seq analysis. The effects of venetoclax and hymeglusin on apoptosis were validated in primary cells. The results showed that HMGCS1 expression was closely associated with apoptosis-related genes based on the data from large clinical databases. B cell lymphoma (BCL)-2 expression was elevated in AML and negatively associated with overall survival. Hymeglusin decreased BCL2 expression levels in HL-60 and KG-1 cells. Venetoclax and hymeglusin inhibited cell viability in both cell lines, but induced apoptosis in HL-60 cells. This discrepancy in sensitivity to hymeglusin may be attributed to the positive increase in the expression levels of HMGCS1 and multiple upregulated pro-leukemia genes in KG-1 cells. Combination treatment with venetoclax and hymeglusin significantly increased the apoptotic rates compared to single-agent treatment in both AML cell lines and primary AML cells. Furthermore, the combination strategy did not result in remarkably enhanced toxicity in normal mononuclear cells. Collectively, hymeglusin enhanced the effects of venetoclax on apoptosis. This combination strategy showed enhanced antileukemic activity with acceptable toxicity in AML.

Itraconazole Inhibits the Growth of Cutaneous Squamous Cell Carcinoma by Targeting HMGCS1/ACSL4 Axis

Background: Cutaneous squamous cell carcinoma (cSCC) is a common cutaneous cancer with increasing incidence. Itraconazole has been identified as a potential anticancer drug candidate. However, the role of itraconazole in cSCC was still unclear. Our objective is exploring the therapeutic potential of itraconazole in cSCC and investigate its molecular mechanism.

Methods: The anti-proliferation effect of itraconazole was tested with CCK-8 assay and clone formation assay. Cell cycle distribution and apoptosis rate were detected using flow cytometry and TUNEL assay, respectively. Transcriptomic and proteomic analyses were used to explore the underlying anti-cancer mechanism. Luciferase reporter assay was used for promoter activity. Reactive oxygen species (ROS), lipid peroxidation and iron accumulation were examined. The in vivo efficacy of itraconazole was assessed in a xenograft model.

Results: Itraconazole inhibited the cell proliferation, induced apoptosis and blocked cell cycle of cSCC cells. An integrated analysis of transcriptomic and proteomic analyses identified that 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) and acyl-CoA synthetase long-chain family member 4 (ACSL4) were significantly upregulated in A431 cells treated with itraconazole. HMGCS1 silencing reversed the antiproliferative activity of itraconazole in A431 cells. Dual-luciferase assay showed that itraconazole could promote HMGCS1 transcription. HMGCS1 silencing abated the expression of ACSL4 in A431 cells. The level of ROS, lipid peroxidation, as well as iron accumulation were increased by itraconazole. Moreover, treatment with itraconazole impeded tumor growth in A431-bearing mice.

Conclusion: We proved itraconazole inhibits the growth of cSCC by regulating HMGCS1/ACSL4 axis.

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

BACKGROUND

Emerging studies reveals that 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) plays vital oncogenic roles in a broad spectrum of human cancers, but there is no pan-cancer evidence on the relationship between HMGCS1 and various tumor types.

AIM

To explore the potential role of HMGCS1 across various tumor types based on big clinical data.

METHODS

We conducted a pan-cancer analysis across more than 30 tumor types, based on the most comprehensive database available, including TCGA, GSCA, clinical proteomic tumor analysis consortium, Kaplan-Meier Plotter dataset, GEPIA2, TIMER2, STRING, and GDSC dataset.

RESULTS

HMGCS1 was highly expressed and negatively correlated with the prognosis in most cancer types. The infiltration levels of cancer associated fibroblast and CD8+ T-cell were closely associated with HMGCS1 expression. Amplification was the most common genetic alteration of HMGCS1 in different cancers, while the frequency of mutation was low. Besides, ACAT2 and MVD were closely correlated and bind to HMGCS1. Pathway enrichment analysis indicated that HMGCS1 was actively involved in steroid biosynthesis. Moreover, high HMGCS1 expression could reduce the sensitivity to most drugs in the GDSC dataset.

CONCLUSIONS

Our study revealed the potential oncogenic role of HMGCS1 in cancers.

HMGCS1 drives drug-resistance in acute myeloid leukemia through endoplasmic reticulum-UPR-mitochondria axis

Hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) is a key enzyme in the mevalonate pathway of cholesterol synthesis. Dysregulation of HMGCS1 expression is a common occurrence in many solid tumors. It was also found to be overexpressed in newly diagnosed (ND) and relapsed/refractory (RR) acute myeloid leukemia (AML) patients. Previous study proved that HMGCS1 could induce drug-resistance in AML cells. However, the underlying mechanism how HMGCS1 contributed to chemoresistance remains elusive. Here, we confirmed that HMGCS1 inhibitor Hymeglusin enhanced cytarabine/Adriamycin (Ara-c/ADR) chemo-sensitivity in AML cells lines. Moreover, Ara-c-resistant HL-60 cells (HL-60/Ara-c) and ADR-resistant HL-60 cells (HL-60/ADR) were more sensitive to HMGCS1 inhibition than HL-60 cells. In addition, we demonstrated that the transcription factor GATA1 was the upstream regulator of HMGCS1 and could directly bind to the HMGCS1 promoter. After treatment of Tunicamycin (Tm), the number of mitochondria was increased and the damage of endoplasmic reticulum (ER) was reduced in bone marrow cells from AML-RR patients, compared to cells from AML-CR group. HMGCS1 protected mitochondria and ER under ER stress and up-regulated unfold protein response (UPR) downstream molecules in AML cells. In summary, we proved that HMGCS1 could upregulate UPR downstream components, protect mitochondria and ER from damage in AML cells under stress, therefore conferring drug resistance. Therefore, HMGCS1 could serve as a novel target for treatment of patients with intolerant chemotherapy and AML-RR patients.

Genetic variants in the cholesterol biosynthesis pathway genes and risk of prostate cancer

Previous studies have found the relationship between cholesterol biosynthesis pathway genes and the risk or prognosis of prostate cancer (PCa), while there is no definite evidence that genetic variants in the cholesterol biosynthesis pathway gene is related to PCa risk. Consequently, we performed this study to explore the associations of single-nucleotide polymorphisms (SNPs) in the cholesterol biosynthesis pathway with PCa risk. We systematically evaluated the association of SNPs in 21 cholesterol biosynthesis pathway genes with the risk of PCa using the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial database using a logistic regression model. Gene expression data of PCa from Gene Expression Omnibus (GEO) datasets and the Cancer Genome Atlas (TCGA) database were applied for mRNA expression analysis. The TCGA database was used to perform expression quantitative trait loci (eQTL) analysis. The interaction between demographic factors and SNPs was analyzed using two-by-four tables. We found T allele of rs67415672 in HMGCS1 is a significant protective allele of PCa [adjusted odds ratio (OR) = 0.90, 95% confidence interval (CI) = 0.83-0.97, P = 4.16 × 10^-3]. Moreover, rs67415672 was an eQTL for HMGCS1 (P = 2.23 × 10^-6). The expression of HMGCS1 significantly decreased in PCa primary tumors than that in normal tissues. These findings indicated that the HMGCS1 rs67415672 might be possible functional susceptibility loci for PCa.

Umbilical cord plasma-derived exosomes from preeclamptic women induce vascular dysfunction by targeting HMGCS1 in endothelial cells

Hypertension is one of the major clinical manifestations of preeclampsia. Vascular dysfunction is crucial for the occurrence and progression of hypertension. Exosomes are emerging as mediators of intercellular communication and can participate in angiogenesis. In this study, we hypothesize that umbilical cord plasma-derived exosomes from preeclamptic women (PE-uexo) impair vascular development by regulating endothelial cells. Here, umbilical cord plasma samples from women with normal pregnancies and matched preeclamptic patients were used to isolate circulating exosomes. Proliferation, Transwell and tube formation assays indicated that PE-uexo impaired the angiogenesis of human umbilical vein endothelial cells (HUVECs). On the basis of microarray analysis of HUVECs treated with PE-uexo or exosomes from women with normal pregnancies, we showed that the expression of 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) was decreased in the PE-uexo-treated HUVECs. Furthermore, downregulation of HMGCS1 in HUVECs attenuated the proliferation and migration of these cells. Interestingly, HMGCS1 was decreased in P0 HUVECs from preeclamptic pregnancies compared with normotensive pregnancies. Together, these observations suggest that PE-uexo disrupts normal function in vascular endothelial cells by targeting HMGCS1, which may result in vascular disorders in the offspring.

The STAT3-miR-223-TGFBR3/HMGCS1 axis modulates the progression of cervical carcinoma

Cervical cancer is induced by persistent infections with high-risk human papillomaviruses (HPVs), which produce the early protein 6 of HPVs (E6)/E7 protein that is involved in cell transformation by interacting with several oncoproteins or tumor suppressors. However, the role of noncoding RNA in mediating the pathogenesis of cervical cancer remains unclear. Here, we report that the novel signal transducer and activator of transcription 3 (STAT3)-microRNA-223-3p (miR-223)-TGFBR3/HMGCS1 axis regulated by the E6 protein controls cervical carcinogenesis. miR-223 was highly expressed in cervical tumor tissues, whereas TGFBR3 or HMGCS1 was significantly downregulated. miR-223 targeted the 3'-UTRs of TGFBR3 and HMGCS1 and suppressed their expression, leading to increased anchorage-independent growth and cervical squamous cell carcinoma (CSCC) tumor growth in vitro and in vivo. The increased expression of miR-223 was mediated by the transcription factor STAT3, whose activity was enhanced by E6 in the context of interleukin (IL)-6 stimulation. In addition, exosomal miR-223 derived from CSCC cells induced IL-6 secretion by monocyte/macrophage in a coculture system in vitro, and IL-6 secretion, in turn, led to enhanced STAT3 activity in CSSC cells, forming a positive feedback loop. Furthermore, modified miR-223 inhibitor effectively suppressed tumor growth in cell line-derived xenograft model, suggesting that miR-223 is a potential promising therapeutic target in CSCC. In conclusion, our results demonstrate that the STAT3-miR-223-HMGCS1/TGFBR3 axis functions as a key signaling pathway in cervical cancer progression and provides a new therapeutic target.

KLF13 suppresses the proliferation and growth of colorectal cancer cells through transcriptionally inhibiting HMGCS1-mediated cholesterol biosynthesis

Background

Colorectal cancer (CRC) is the fourth most deadly malignancy throughout the world. Extensive studies have shown that Krüppel-like factors (KLFs) play essential roles in cancer development. However, the function of KLF13 in CRC is unclear.

Methods

The Cancer Genome Atlas database was applied to analyze the expression of KLF13 in CRC and normal tissues. Lentivirus system was used to overexpress and to knock down KLF13. RT-qPCR and Western blot assays were performed to detect mRNA and protein expression. CCK-8, colony formation, cell cycle analysis and EdU staining were used to assess the in vitro function of KLF13 in CRC cells. Xenografter tumor growth was used to evaluate the in vivo effect of KLF13 in CRC. Cholesterol content was measured by indicated kit. Transcription activity was analyzed by luciferase activity measurement. ChIP-qPCR assay was performed to assess the interaction of KLF13 to HMGCS1 promoter.

Results

KLF13 was downregulated in CRC tissues based on the TCGA database and our RT-qPCR and Western blot results. Comparing with normal colorectal cells NCM460, the CRC cells HT-26, HCT116 and SW480 had reduced KLF13 expression. Functional experiments showed that KLF13 knockdown enhanced the proliferation and colony formation in HT-29 and HCT116 cells. Opposite results were observed in KLF13 overexpressed cells. Furthermore, KLF13 overexpression resulted in cell cycle arrest at G0/G1 phase, reduced EdU incorporation and suppressed tumor growth of HCT116 cells in nude mice. Mechanistically, KLF13 transcriptionally inhibited HMGCS1 and the cholesterol biosynthesis. Knockdown of HMGCS1 suppressed cholesterol biosynthesis and the proliferation of CRC cells with silenced KLF13. Furthermore, cholesterol biosynthesis inhibitor significantly retarded the colony growth in both cells.

Conclusions

Our study reveals that KLF13 acts as a tumor suppressor in CRC through negatively regulating HMGCS1-mediated cholesterol biosynthesis.

Mevalonate Pathway Enzyme HMGCS1 Contributes to Gastric Cancer Progression

The 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) is a potential regulatory node in the mevalonate pathway that is frequently dysregulated in tumors. This study found that HMGCS1 expression is upregulated in stomach adenocarcinoma samples of patients and tumorspheres of gastric cancer cells. HMGCS1 elevates the expression levels of the pluripotency genes Oct4 and SOX-2 and contributes to tumorsphere formation ability in gastric cancer cells. HMGCS1 also promotes in vitro cell growth and progression and the in vivo tumor growth and lung metastasis of gastric cancer cells. After blocking the mevalonate pathway by statin and dipyridamole, HMGCS1 exerts nonmetabolic functions in enhancing gastric cancer progression. Furthermore, the level and nuclear translocation of HMGCS1 in gastric cancer cells are induced by serum deprivation. HMGCS1 binds to and activates Oct4 and SOX-2 promoters. HMGCS1 also enhances the integrated stress response (ISR) and interacts with the endoplasmic reticulum (ER) stress transducer protein kinase RNA-like endoplasmic reticulum kinase (PERK). Our results reveal that HMGCS1 contributes to gastric cancer progression in both metabolic and nonmetabolic manners.

Molecular cloning and cellular expression of the cholesterol synthesizing enzymes during the prenatal development of the optic nerve in the dromedary camel (Camelus Dromedarius)

The Cholesterol-synthesizing proteins (HMGCS1 and HMGCS2) are mitochondrial enzymes that believed to catalyze the first reaction of ketogenesis, the process by which energy is provided from fats in the absence of carbohydrates. Typically, astrocytes developed from its progenitor cells in the embryonic optic nerve and enriched with HMGCS1 and 2. However, the detailed histomorphology of camel HMGCS1 and 2 remains to be clearly defined. Here, we investigated the changes that associate with astrocytes differentiation within the developing camel optic nerve. Firstly, we isolated cDNAs encoding HMGCS1 and 2 from the optic nerve. Then, we found that HMGCS1 shared high similarity to human, while HMGCS2 showed a lower similarity and was more diverse. Immunohistochemical studies revealed that distinct correlation of astrocytes differentiation with HMGCS1 and 2 expressions in the developing camel optic nerve. Both encoded proteins were localized throughout the cytoplasm, as well as the nuclei of the astrocytes. In addition, semi-quantitative PCR analysis and western analysis confirmed that both HMGCS1 and 2 were highly expressed in camel optic nerve as well as other tissue, but they were lower in both skeletal and heart muscles. Moreover, various stains such as Sudan black and florescence filipin stains were used to visualize the free cholesterol in the astrocytes, indicating the enzymatic activity of HMGCS1 and 2. Together, our study reported the first comprehensive investigation of the molecular cloning and cellular expression of HMGCS1 and 2 in the optic nerve of dromedary camel.

Stromal regulation of prostate cancer cell growth by mevalonate pathway enzymes HMGCS1 and HMGCR

It has been suggested that the tumor microenvironment plays an important role in tumor progression, acquisition of androgen independence, and distant metastasis in prostate cancer (PC). However, little is known about the transcriptional basis of cellular interactions in the human PC microenvironment. To clarify the mechanism of PC progression and metastasis, we investigated the interaction of PC, epithelial, and stromal cells using genome-wide gene expression profiling. We hypothesized that PC cells could induce stromal cells to differentiate into so-called cancer-associated fibroblasts (CAFs), which might contribute to cancer invasion and metastasis. Genes upregulated in normal human prostate stromal cells (PrSC) co-cultured with human PC cells (LNCaP) included the mevalonate pathway enzymes 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). Knockdown of endogenous HMGCS1 or HMGCR in PC cells by shRNA resulted in a significant reduction of PC cell viability. Importantly, exogenous overexpression of HMGCS1 or HMGCR in either PC cells or prostate stromal cells stimulated PC cell growth, suggesting a possible autocrine/paracrine mechanism of action. Immunohistochemical analysis confirmed that HMGCS1 and HMGCR were overexpressed in PC stroma, especially in early stage PC. These results provide clues to the molecular mechanisms underlying PC invasion and metastasis, and suggest that HMGCS1 and HMGCR in PC, as well as in PC stroma, might serve as molecular targets for the treatment of PC.

HMG-CoA synthase 1 is a synthetic lethal partner of BRAFV600E in human cancers

Contributions of metabolic changes to cancer development and maintenance have received increasing attention in recent years. Although many human cancers share similar metabolic alterations, it remains unclear whether oncogene-specific metabolic alterations are required for tumor development. Using an RNAi-based screen targeting the majority of the known metabolic proteins, we recently found that oncogenic BRAF^V600E up-regulates HMG-CoA lyase (HMGCL), which converts HMG-CoA to acetyl-CoA and a ketone body, acetoacetate, that selectively enhances BRAF^V600E-dependent MEK1 activation in human cancer. Here, we identified HMG-CoA synthase 1 (HMGCS1), the upstream ketogenic enzyme of HMGCL, as an additional "synthetic lethal" partner of BRAF^V600E Although HMGCS1 expression did not correlate with BRAF^V600E mutation in human melanoma cells, HMGCS1 was selectively important for proliferation of BRAF^V600E-positive melanoma and colon cancer cells but not control cells harboring active N/KRAS mutants, and stable knockdown of HMGCS1 only attenuated colony formation and tumor growth potential of BRAF^V600E melanoma cells. Moreover, cytosolic HMGCS1 that co-localized with HMGCL and BRAF^V600E was more important than the mitochondrial HMGCS2 isoform in BRAF^V600E-expressing cancer cells in terms of acetoacetate production. Interestingly, HMGCL knockdown did not affect HMGCS1 expression levels, whereas HMGCS1 knockdown caused a compensating increase in HMGCL protein level because of attenuated protein degradation. However, this increase did not reverse the reduced ketogenesis in HMGCS1 knockdown cells. Mechanistically, HMGCS1 inhibition decreased intracellular acetoacetate levels, leading to reduced BRAF^V600E-MEK1 binding and consequent MEK1 activation. We conclude that the ketogenic HMGCS1-HMGCL-acetoacetate axis may represent a promising therapeutic target for managing BRAF^V600E-positive human cancers.