acetyl-CoA Acetyltransferase 1 Research Articles

ACAT1 suppresses clear cell renal cell carcinoma progression by AMPK mediated fatty acid metabolism

Renal cell carcinoma (RCC) stands as a prevalent malignancy within urological pathology, exhibiting a noteworthy escalation in its incidence. Despite being a mitochondrial enzyme, the precise role of Acetyl-CoA Acetyltransferase 1 (ACAT1) in RCC remains elusive. In this investigation, we employed bioinformatics methodologies to assess the expression patterns and prognostic significance across various RCC subtypes, encompassing clear cell renal cell carcinoma (ccRCC), papillary cell carcinoma, and chromophobe cell carcinoma. Our findings unveil a close correlation between ACAT1 expression and the prognostic implications specifically within ccRCC. Through both in vitro and in vivo overexpression studies, we delineated the functional and mechanistic facets of ACAT1 in impeding the progression of ccRCC. Our results unequivocally demonstrated that ACAT1 overexpression markedly curtailed proliferation, invasion, and metastasis of ccRCC cells in both in vivo models and cell cultures. Mechanistically, ACAT1’s inhibitory effect on the AMPK signaling pathway orchestrated a regulatory role in modulating fatty acid metabolism, thereby effectively restraining the advancement of ccRCC. Collectively, our findings underscore ACAT1 as a pivotal tumor suppressor, instrumental in curtailing the proliferation, migration, and invasion of ccRCC by governing fatty acid metabolism through the AMPK signaling pathway. These insights posit ACAT1 as a potential predictive biomarker and therapeutic target warranting further exploration in RCC management.

Shi-pi-xiao-ji formula suppresses hepatocellular carcinoma by reducing cellular stiffness through upregulation of acetyl-coA acetyltransferase 1.

Previous studies have shown that the Shi-pi-xiao-ji (SPXJ) herbal decoction formula is effective in suppressing hepatocellular carcinoma (HCC), but the underlying mechanisms are not known. Therefore, this study investigated whether the antitumor effects of the SPXJ formula in treating HCC were mediated by acetyl-coA acetyltransferase 1 (ACAT1)-regulated cellular stiffness. Through a series of experiments, we concluded that SPXJ inhibits the progression of HCC by upregulating the expression level of ACAT1, lowering the level of cholesterol in the cell membrane, and altering the cellular stiffness, which provides a new idea for the research of traditional Chinese medicine against HCC. To investigate the anti-tumor effects of the SPXJ formula on the malignant progression of HCC. HCC cells were cultured in vitro with SPXJ-containing serum prepared by injecting SPXJ formula into wild-type mice. The apoptotic rate and proliferative, invasive, and migratory abilities of control and SPXJ-treated HCC cells were compared. Atomic force microscopy was used to determine the cell surface morphology and the Young's modulus values of the control and SPXJ-treated HCC cells. Plasma membrane cholesterol levels in HCC cells were detected using the Amplex Red cholesterol detection kit. ACAT1 protein levels were estimated using western blotting. Compared with the vehicle group, SPXJ serum considerably reduced proliferation of HCC cells, increased stiffness and apoptosis of HCC cells, inhibited migration and invasion of HCC cells, decreased plasma membrane cholesterol levels, and upregulated ACAT1 protein levels. However, treatment of HCC cells with the water-soluble cholesterol promoted proliferation, migration, and invasion of HCC cells as well as decreased cell stiffness and plasma membrane cholesterol levels, but did not alter the apoptotic rate and ACAT1 protein expression levels compared with the vehicle control. SPXJ formula inhibited proliferation, invasion, and migration of HCC cells by decreasing plasma membrane cholesterol levels and altering cellular stiffness through upregulation of ACAT1 protein expression.

Modulating Cholesterol Metabolism via ACAT1 Knockdown Enhances Anti-B-Cell Lymphoma Activities of CD19-Specific Chimeric Antigen Receptor T Cells by Improving the Cell Activation and Proliferation.

CD19-specific CAR-T immunotherapy has been extensively studied for the treatment of B-cell lymphoma. Recently, cholesterol metabolism has emerged as a modulator of T lymphocyte function and can be exploited in immunotherapy to increase the efficacy of CAR-based systems. Acetyl-CoA acetyltransferase 1 (ACAT1) is the major cholesterol esterification enzyme. ACAT1 inhibitors previously shown to modulate cardiovascular diseases are now being implicated in immunotherapy. In the present study, we achieved knockdown of ACAT1 in T cells via RNA interference technology by inserting ACAT1-shRNA into anti-CD19-CAR-T cells. Knockdown of ACAT1 led to an increased cytotoxic capacity of the anti-CD19-CAR-T cells. In addition, more CD69, IFN-γ, and GzmB were expressed in the anti-CD19-CAR-T cells. Cell proliferation was also enhanced in both antigen-independent and antigen-dependent manners. Degranulation was also improved as evidenced by an increased level of CD107a. Moreover, the knockdown of ACAT1 led to better anti-tumor efficacy of anti-CD19 CAR-T cells in the B-cell lymphoma mice model. Our study demonstrates novel CAR-T cells containing ACAT1 shRNA with improved efficacy compared to conventional anti-CD19-CAR-T cells in vitro and in vivo.

ACAT1 promotes proliferation and metastasis of bladder cancer via AKT/GSK3β/c-Myc signaling pathway.

Acetyl-CoA acetyltransferase 1 (ACAT1) plays a significant role in the regulation of gene expression and tumorigenesis. However, the biological role of ACAT1 in bladder cancer (BLCA) has yet to be elucidated. This research aimed to elucidate the bioinformatics features and biological functions of ACAT1 in BLCA. Here, we demonstrate that ACAT1 is elevated in BLCA tissues and is correlated with specific clinicopathological features and an unfavorable prognosis for survival in BLCA patients. ACAT1 was identified as an independent risk factor in BLCA. Phenotypically, both in vitro and in vivo, ACAT1 knockdown suppressed BLCA cell proliferation and migration, while ACAT1 overexpression had the opposite effect. Mechanistic assays revealed that ACAT1 enhances BLCA cell proliferation and metastasis through the AKT/GSK3β/c-Myc signaling pathway by modulating the cell cycle and EMT. Taken together, the results of our study reveal that ACAT1 is an oncogenic driver in BLCA that enhances tumor proliferation and metastasis, indicating its potential as a diagnostic and therapeutic target for this disease.

Abstract 16157: Impaired Branched Chain Amino Acid Metabolism in Porcine Right Atrial Dysfunction

Background: Right atrial (RA) dysfunction is prevalent and an early predictor of mortality in pulmonary arterial hypertension (PAH). At present, the underlying pathobiology of RA dysfunction is not well defined, and thus approaches are needed to delineate potential therapeutic pathways to hopefully improve outcomes in PAH. Methods: Surgical pulmonary artery banding induced right ventricular and right atrial dysfunction in male piglets. 6 weeks post-banding, cardiovascular magnetic resonance imaging quantified cardiac structure/function. Right atrial and ventricular tissue was subjected to quantitative proteomics and targeted metabolomics. Results: PAB piglets had decreased RA ejection fraction (RAEF) and increased RA end-systolic volume. Pathway analysis revealed proteins responsible for branched chain amino acid (BCAA) degradation, including MCEE (Methylmalonyl CoA Epimerase), DLD (Dihydrolipoamide Dehydrogenase), HIBADH (3-hydroxyisobutyrate Dehydrogenase), ACAT1 (Acetyl-CoA Acetyltransferase 1), and IVD (Isovaleryl-CoA Dehydrogenase), were reduced in PAB RAs, which was not observed in RV tissue. Targeted metabolomics analysis demonstrated BCAAs were elevated in the RA of PAB piglets and BCAA levels were strongly and inversely associated with RAEF. Conclusions: Deranged BCAA metabolism is uniquely observed in the dysfunctional RA, which offers a new therapeutic target for this important clinical problem.

SCD1 inhibition enhances the effector functions of CD8+ T cells via ACAT1-dependent reduction of esterified cholesterol.

We previously reported that the inhibition of stearoyl-CoA desaturase 1 (SCD1) enhances the antitumor function of CD8+ T cells indirectly via restoring production of DC recruiting chemokines by cancer cells and subsequent induction of antitumor CD8+ T cells. In this study, we investigated the molecular mechanism of direct enhancing effects of SCD1 inhibitors on CD8+ T cells. In vitro treatment of CD8+ T cells with SCD1 inhibitors enhanced IFN-γ production and cytotoxic activity of T cells along with decreased oleic acid and esterified cholesterol, which is generated by cholesterol esterase, acetyl-CoA acetyltransferase 1 (ACAT1), in CD8+ T cells. The addition of oleic acid or cholesteryl oleate reversed the enhanced functions of CD8+ T cells treated with SCD1 inhibitors. Systemic administration of SCD1 inhibitor to MCA205 tumor-bearing mice enhanced IFN-γ production of tumor-infiltrating CD8+ T cells, in which oleic acid and esterified cholesterol, but not cholesterol, were decreased. These results indicated that SCD1 suppressed effector functions of CD8+ T cells through the increased esterified cholesterol in an ACAT1-dependent manner, and SCD1 inhibition enhanced T cell activity directly through decreased esterified cholesterol. Finally, SCD1 inhibitors or ACAT1 inhibitors synergistically enhanced the antitumor effects of anti-PD-1 antibody therapy or CAR-T cell therapy in mouse tumor models. Therefore, the SCD1-ACAT1 axis is regulating effector functions of CD8+ T cells, and SCD1 inhibitors, and ACAT1 inhibitors are attractive drugs for cancer immunotherapy.

A rare case of β-ketothiolase deficiency presenting as mimicker of diabetic ketoacidosis

β-ketothiolase (3-oxothiolase, BKT), also called mitochondrial acetoacetyl-coenzyme-A thiolase (T2), is a mitochondrial enzyme involved in isoleucine catabolism and ketone metabolism. BKT or T2 deficiency is inherited as an autosomal recessive trait and results in a rare inborn error of metabolism called alpha-acetoacetic aciduria. Patients with this disorder usually present with intermittent attacks of ketoacidosis. Here, we report a case of BKT deficiency that mimicked diabetic ketoacidosis (DKA) at presentation and discuss the clinical profile and interpretation of laboratory findings. An 8-month-old male child presented with seizures, coma, hyperglycemia, shock, and high anion gap metabolic acidosis with normal serum lactate and negative urinary ketone requiring correction with sodium bicarbonate, management of shock and sepsis, and mechanical ventilation. During his stay in the hospital, he developed ketonuria and episodes of hypoglycemia on a glucose insulin infusion with persistent metabolic acidosis which prompted us to look for an inborn error of metabolism, as hemoglobin A1C (HbA1C) and C-peptide levels were normal. Both tandem mass spectrometry (TMS) and urinary gas chromatography mass spectrometry (GCMS) were confirmatory. Diagnosis of BKT deficiency was further confirmed with genetic testing which revealed a novel homozygous mutation in the acetyl-CoA acetyltransferase 1 (ACAT1) gene. In infants manifesting with clinical features of diabetic ketoacidosis (DKA), cautious interpretation of laboratory findings and consideration of inborn errors of metabolism including the rare BKT deficiency are needed for a favorable outcome and prediction of prognosis.

ACAT1 deficiency in myeloid cells promotes glioblastoma progression by enhancing the accumulation of myeloid-derived suppressor cells

Glioblastoma (GBM) is a highly aggressive and lethal brain tumor with an immunosuppressive tumor microenvironment (TME). In this environment, myeloid cells, such as myeloid-derived suppressor cells (MDSCs), play a pivotal role in suppressing antitumor immunity. Lipometabolism is closely related to the function of myeloid cells. Here, our study reports that acetyl-CoA acetyltransferase 1 (ACAT1), the key enzyme of fatty acid oxidation (FAO) and ketogenesis, is significantly downregulated in the MDSCs infiltrated in GBM patients. To investigate the effects of ACAT1 on myeloid cells, we generated mice with myeloid-specific (LyzM-cre) depletion of ACAT1. The results show that these mice exhibited a remarkable accumulation of MDSCs and increased tumor progression both ectopically and orthotopically. The mechanism behind this effect is elevated secretion of C–X–C motif ligand 1 (CXCL1) of macrophages (Mφ). Overall, our findings demonstrate that ACAT1 could serve as a promising drug target for GBM by regulating the function of MDSCs in the TME.

Role of acetyl-CoA acetyltransferase 1 expression in the molecular mechanism of adenomyosis.

Adenomyosis is a benign uterine illness characterized by endometrial gland and stromal invasion into the myometrium. Acetyl-CoA acetyltransferase 1 (ACAT1) is an enzyme localized in mitochondria that is involved in ketogenesis and ketolysis processes by reversibly catalyzing the formation of acetoacetyl-CoA from two acetyl-CoA molecules. The current study investigated the expression of the ACAT1 molecule in tissue samples of patients diagnosed with adenomyosis and healthy endometrial tissues. It is aimed to determine the differences in ACAT1 gene expression and in this way to discover the first information about the role of ACAT1 in the development and molecular mechanism of adenomyosis. In the current retrospective study, formalin-fixed paraffin-embedded archival tissues were employed. A total of 76 patient samples were included in the study. Of these samples, 28 are adenomyotic tissue (Group I), 30 are eutopic endometrial tissue (Group II), and 18 are the Control Group. In these groups, the expression levels of the ACAT1 gene were determined by the reverse transcription-polymerase chain reaction method. When the expression results of the ACAT1 gene were evaluated, statistically significant differences were found between the groups (p<0.05). There was a difference between Group I-Group II and Group I-Control Group regarding the ACAT1 gene. No statistically significant change was observed between Group II and Control Group. It is a remarkable finding that the expression of ACAT1 in adenomyosis tissue is decreased compared with both eutopic endometrium and control groups tissues. The results suggest that ACAT1 may be associated with the molecular pathogenesis of adenomyosis.

Persistent organic pollutants promote aggressiveness in prostate cancer.

Increasing evidence points towards a causal link between exposure to persistent organic pollutants (POPs) with increased incidence and aggressivity of various cancers. Among these POPs, dioxin and PCB-153 are widely found in our environment and represent a significant source of contamination. Dioxin exposure has already been linked to cancer such as non-Hodgkin's lymphoma, but remains to be more extensively investigated in other cancers. Potential implications of dioxin and PCB-153 in prostate cancer progression spurred us to challenge both ex vivo and in vivo models with low doses of these POPs. We found that dioxin or PCB-153 exposure increased hallmarks of growth and metastasis of prostate cancer cells ex vivo and in grafted NOD-SCID mice. Exposure induced histopathological carcinoma-like patterns in the Ptenpc-/- mice. We identified up-regulation of Acetyl-CoA Acetyltransferase-1 (ACAT1) involved in ketone bodies pathway as a potential target. Mechanistically, genetic inhibition confirmed that ACAT1 mediated dioxin effect on cell migration. Using public prostate cancer datasets, we confirmed the deregulation of ACAT1 and associated gene encoded ketone bodies pathway enzymes such as OXCT1, BDH1 and HMGCL in advanced prostate cancer. To further explore this link between dioxin and ACAT1 deregulation, we analyzed a unique prostate-tumour tissue collection from the USA veterans exposed to agent orange, known to be highly contaminated by dioxin because of industrial production. We found that ACAT1 histoscore is significantly increased in exposed patients. Our studies reveal the implication of dioxin and PCB-153 to induce a prometastatic programme in prostate tumours and identify ACAT1 deregulation as a key event in this process.

Avasimibe can cooperate with a DC-targeting and integration-deficient lentivector to induce stronger HBV specific T cytotoxic response by regulating cholesterol metabolism

We have reported a lentivector which could effectively induce HBV-specific cytotoxic T lymphocytes (CTLs). Avasimibe is an inhibitor of acetyl-CoA acetyltransferase-1 (ACAT1), and has been shown to enhance T lymphocyte cytotoxicity on tumor cells. However, the role of avasimibe in lentivector-induced HBV-specific T cytotoxic response remains unknown. Based on previous study, we constructed an integration-deficient lentivector LVDC-ID-HBV (harboring HBcAg expression), and the in vitro experiments showed that the combination of avasimibe exhibited better efficacy in inducing HBV-specific CTL responses including cell proliferation, production of cytokines, as well as CTL killing activities. Mechanism experiments showed that increasing cell membrane cholesterol levels by MβCD-coated cholesterol or ACAT1 inhibition efficiently promoted TCR clustering, signaling transduction and immunological synapse formation, thereby mediating augmented CTL responses. Nevertheless, the depletion of plasma membrane cholesterol with MβCD led to obviously decreased CTL responses. The avasimibe-mediated strengthened immune effects were also determined in animal experiments and the results were in agreement with those from the in vitro research. In particular, the in vivo CTL killing activities were identified by the CFSE or BV-labeled splenocyte lysis assay. Moreover, the experiments in HBV transgenic mice showed that the LVDC-ID-HBV plus avasimibe group demonstrated the lowest serum HBsAg and HBV DNA levels, as well as the lowest expression of HBsAg and HBcAg in liver tissues. We concluded that the HBV-specific CTL immune responses could be potentiated by avasimibe through regulating plasma membrane cholesterol levels. Avasimibe may be a potential adjuvant for lentivector vaccine against HBV infection.

Effects of UBE3A on Cell and Liver Metabolism through the Ubiquitination of PDHA1 and ACAT1.

Nonalcoholic fatty liver disease (NAFLD) is substantiated by the reprogramming of liver metabolic pathways that disrupts the homeostasis of lipid and glucose metabolism and thus promotes the progression of the disease. The metabolic pathways associated with NAFLD are regulated at different levels from gene transcription to various post-translational modifications including ubiquitination. Here, we used a novel orthogonal ubiquitin transfer platform to identify pyruvate dehydrogenase A1 (PDHA1) and acetyl-CoA acetyltransferase 1 (ACAT1), two important enzymes that regulate glycolysis and ketogenesis, as substrates of E3 ubiquitin ligase UBE3A/E6AP. We found that overexpression of UBE3A accelerated the degradation of PDHA1 and promoted glycolytic activities in HEK293 cells. Furthermore, a high-fat diet suppressed the expression of UBE3A in the mouse liver, which was associated with increased ACAT1 protein levels, while forced expression of UBE3A in the mouse liver resulted in decreased ACAT1 protein contents. As a result, the mice with forced expression of UBE3A in the liver exhibited enhanced accumulation of triglycerides, cholesterol, and ketone bodies. These results reveal the role of UBE3A in NAFLD development by inducing the degradation of ACAT1 in the liver and promoting lipid storage. Overall, our work uncovers an important mechanism underlying the regulation of glycolysis and lipid metabolism through UBE3A-mediated ubiquitination of PDHA1 and ACAT1 to regulate their stabilities and enzymatic activities in the cell.

ACAT1-mediated METTL3 acetylation inhibits cell migration and invasion in triple negative breast cancer.

Triple-negative breast cancer (TNBC) is a heterogeneous and aggressive disease with poor prognosis. Acetylation modifications affect a great number of biological processes of malignant tumors. The current study aims at revealing the role of acetylation-related mechanism in TNBC progression. Methyltransferase like-3 (METTL3) was found to be downregulated in TNBC cells via quantitative polymerase chain reaction (qPCR) and western blot analyses. Co-Immunoprecipitation (Co-IP) and GST pulldown assays revealed the interaction between acetyl-CoA acetyltransferase 1 (ACAT1) and METTL3. Through further immunoprecipitation (IP) assay, we determined that ACAT1 stabilizes METTL3 protein via inhibiting the degradation of ubiquitin-proteasome. Functionally, ACAT1 inhibits TNBC cell migration and invasion. Moreover, nuclear receptor subfamily 2 group F member 6 (NR2F6) regulates ACAT1 expression at transcriptional level. Finally, we demonstrated that NR2F6/ACAT/METTL3 axis suppresses the migration and invasion of TNBC cells via METTL3. In conclusion, NR2F6 transcriptionally activates ACAT1 and promotes the suppressive effects of ACAT1-mediated METTL3 acetylation on TNBC cell migration and invasion.

Screening of candidate genes related to differences in growth and development between Chinese indigenous and Western pig breeds.

Neijiang (NJ) and Yacha (YC) are two indigenous pig breeds in the Sichuan basin of China, displaying higher resistance to diseases, lower lean ratio, and slower growth rate than the commercial Western pig breed Yorkshire (YS). The molecular mechanisms underlying the differences in growth and development between these pig breeds are still unknown. In the present study, five pigs from NJ, YC, and YS breeds were subjected to the whole genome resequencing, and then the differential single-nucleotide polymorphisms (SNPs) were screened using a 10-kb window sliding in 1-kb step using the Fst method. Finally, 48,924, 48,543, and 46,228 nonsynonymous single-nucleotide polymorphism loci (nsSNPs) were identified between NJ and YS, NJ and YC, and YC and YS, which highly or moderately affected 2,490, 800, and 444 genes, respectively. Moreover, three nsSNPs were detected in the genes of acetyl-CoA acetyltransferase 1 (ACAT1) insulin-like growth factor 2 receptor (IGF2R), insulin-like growth factor 2 and mRNA-binding protein 3 (IGF2BP3), which potentially affected the transformation of acetyl-CoA to acetoacetyl-CoA and the normal functions of the insulin signaling pathways. Moreover, serous determinations revealed significantly lower acetyl-CoA content in YC than in YS, supporting that ACAT1 might be a reason explaining the differences in growth and development between YC and YS breeds. Contents of phosphatidylcholine (PC) and phosphatidic acid (PA) significantly differed between the pig breeds, suggesting that glycerophospholipid metabolism might be another reason for the differences between Chinese and Western pig breeds. Overall, these results might contribute basic information to understand the genetic differences determining the phenotypical traits in pigs.

Cancer Metabolism: Fasting Reset, the Keto-Paradox and Drugs for Undoing

In tumor cells, ketolysis "via" succinyl-CoA: 3-oxoacid-CoAtransferase (SCOT) and acetyl-CoA acetyltransferase 1 (ACAT1) is a major source of mitochondrial acetyl-CoA. Active ACAT1 tetramers stabilize by tyrosine phosphorylation, which facilitates the SCOT reaction and ketolysis. Tyrosine phosphorylation of pyruvate kinase PK M2 has the opposite effect, stabilizing inactive dimers, while pyruvate dehydrogenase (PDH), which is already inhibited by phosphorylation, is acetylated by ACAT1 and is doubly locked. This closes the glycolytic supply of acetyl-CoA. In addition, since tumor cells must synthesize fatty acids to create new membranes, they automatically turn off the degradation of fatty acids into acetyl-CoA ("via" the malonyl-CoA brake for the fatty acid carnityl transporter). Thus, inhibiting SCOT the specific ketolytic enzyme and ACAT1 should hold back tumor progression. However, tumor cells are still able to take up external acetate and convert it into acetyl-CoA in their cytosol "via" an acetyl-CoA synthetase, which feeds the lipogenic pathway; additionally, inhibiting this enzyme would make it difficult for tumor cells to form new lipid membrane and survive.

Autophagy inhibition and reactive oxygen species elimination by acetyl-CoA acetyltransferase 1 through fused in sarcoma protein to promote prostate cancer

BackgroundProstate cancer is a major health issue affecting the male population worldwide, and its etiology remains relatively unknown. As presented on the Gene Expression Profiling Interactive Analysis database, acetyl-CoA acetyltransferase 1 (ACAT1) acts as a prostate cancer-promoting factor. ACAT1 expression in prostate cancer tissues is considerably higher than that in normal tissues, leading to a poor prognosis in patients with prostate cancer. Here, we aimed to study the role of the ACAT1-fused in sarcoma (FUS) complex in prostate cancer and identify new targets for the diagnosis and treatment of the disease.MethodsWe conducted immunohistochemical analysis of 57 clinical samples and in vitro and in vivo experiments using a mouse model and plasmid constructs to determine the expression of ACAT1 in prostate cancer.ResultsThe relationship between the expression of ACAT1 and the Gleason score was significant. The expression of ACAT1 was higher in tissues with a Gleason score of > 7 than in tissues with a Gleason score of ≤7 (P = 0.0011). In addition, we revealed that ACAT1 can interact with the FUS protein.ConclusionsIn prostate cancer, ACAT1 promotes the expression of P62 and Nrf2 through FUS and affects reactive oxygen species scavenging. These effects are due to the inhibition of autophagy by ACAT1. That is, ACAT1 promotes prostate cancer by inhibiting autophagy and eliminating active oxygen species. The expression of ACAT1 is related to prostate cancer. Studying the underlying mechanism may provide a new perspective on the treatment of prostate cancer.

Atorvastatin improves cisplatin sensitivity through modulation of cholesteryl ester homeostasis in breast cancer cells.

Acquired treatment resistance is a significant problem in breast cancer management, and alterations in lipid metabolism have been proposed to contribute to the development of drug resistance as well as other aspects of tumor progression. The present study aimed to identify the role of cholesterol metabolism in MCF-7 and MDA-MB-231 breast cancer cell response to cisplatin (CDDP) treatment in the acute setting and in a model of CDDP resistance. MCF-7 (luminal A), MDA-MB-231 (triple-negative) and CDDP-resistant MDA-MB-231 (MDACR) cell lines were grown in the presence or absence of CDDP in combination with atorvastatin (ATV), lipid depletion or low-density lipoprotein loading and were analyzed by a variety of biochemical and radiometric techniques. Co-administration of CDDP and ATV strongly reduced cell proliferation and viability to a greater extent than CDDP alone, especially in MDA-MB-231 cells. These findings were associated with reduced cholesteryl ester synthesis and storage in MDA-MB-231 cells. In MDACR cells, acetyl-CoA acetyltransferase 1 (ACAT-1) was upregulated compared to naïve MDA-MB-231 cells and ATV treatment restored CDDP sensitivity, suggesting that aberrant ACAT-1 expression and associated changes in cholesterol metabolism contribute to CDDP resistance in MDA-MB-231 cells. These findings indicate that the elevated susceptibility of MDA-MB-231 cells to co-administration of CDDP and ATV, is associated with an increased reliance on cholesteryl ester availability. Our data from these cell culture-based studies identifies altered cholesterol homeostasis as an adaptive response to CDDP treatment that contributes to aggressiveness and chemotherapy resistance.

Avasimibe Alleviates Disruption of the Airway Epithelial Barrier by Suppressing the Wnt/β-Catenin Signaling Pathway.

Avasimibe (Ava) is an acetyl-CoA acetyltransferase 1 (ACAT1) specific inhibitor and an established medicine for atherosclerosis, owing to its excellent and safe anti-inflammation effects in humans. However, its efficacy in asthma has not yet been reported. We first administered varying concentrations of avasimibe to house dust mite (HDM)-induced asthmatic mice; results showed that 20 mg/kg avasimibe most significantly reduced IL-4 and IL-5 production in bronchoalveolar lavage fluid (BALF) and total IgE in serum, and the avasimibe treatment also exhibited lower mucus secretion, decreased goblet and basal cells but increased ciliated cells compared to the HDM group. And the redistribution of adherens junction (AJ) proteins induced by HDM was far more less upon avasimibe administration. However, avasimibe did not reduce the cholesterol ester ratio in lung tissues or intracellular cholesterol ester, which is avasimibe’s main effect. Further analysis confirmed that avasimibe impaired epithelial basal cell proliferation independent of regulating cholesterol metabolism and we analyzed datasets using the Gene Expression Omnibus (GEO) database and then found that the KRT5 gene (basal cell marker) expression is correlated with the β-catenin gene. Moreover, we found that β-catenin localized in cytomembrane upon avasimibe treatment. Avasimibe also reduced β-catenin phosphorylation in the cytoplasm and inactivated the Wnt/β-catenin signaling pathway induced by HDMs, thereby alleviating the airway epithelial barrier disruption. Taken together, these findings indicated that avasimibe has potential as a new therapeutic option for allergic asthma.

Cholesterol metabolism and lipid droplet vacuoles; a potential target for the therapy of aggressive lymphoma.

Cholesterol uptake via LDL receptor (LDLR) is increased in some malignant tumors, and incorporated LDL contribute to lipid droplet formation. Burkitt's lymphoma is known to have a large number of vacuoles in the cytoplasm, however, intracellular vacuoles are also seen in high-grade lymphomas such as adult T-cell leukemia/lymphoma, diffuse large B-cell lymphoma and primary central nervous system lymphoma. Recent studies have shown that esterified cholesterol is the main component of these vacuoles and the expression of cholesterol metabolism-related molecules such as LDLR, acetyl-CoA acetyltransferase 1 (ACAT1) which esterifies free cholesterol, and scavenger receptor class B type I (SR-BI) which effluxes free cholesterol, was significantly upregulated in lymphoma cells. Moreover, negative feedback of LDLR was not regulated even under cholesterol-rich conditions in lymphoma cells. We found that cytoplasmic free cholesterol was increased by ACAT and SR-BI inhibitors (CI-976 and BLT-1, respectively), and the accumulation of free cholesterol induced lymphoma cell apoptosis. In addition, overexpression of lipid droplet surface proteins has been correlated with poor prognosis in several malignant tumor such as ovarian cancer and clear cell renal cell carcinoma, and it is important to evaluate lipid droplet formation in malignant tumors including lymphomas.

Multi-Omics Integration to Reveal the Mechanism of Hepatotoxicity Induced by Dictamnine.

Herb-induced liver injury (HILI) has become a great concern worldwide due to the widespread usage of herbal products. Among these products is Dictamni Cortex (DC), a well-known Traditional Chinese Medicine (TCM), widely used to treat chronic dermatosis. Dictamni Cortex has drawn increasing attention because of its hepatotoxicity caused by the hepatotoxic component, dictamnine. However, the potential hepatotoxicity mechanism of dictamnine remains unclear. Therefore, this study aimed to use the multi-omics approach (transcriptomic, metabolomic, and proteomic analyses) to identify genes, metabolites, and proteins expressions associated with dictamnine-induced hepatotoxicity. A study on mice revealed that a high dose of dictamnine significantly increases serum aspartate aminotransferase (AST) activity, total bilirubin (TBIL), and direct bilirubin (DBIL) levels, the relative liver weight and liver/brain weight ratio in female mice (P < 0.05 and P < 0.01), compared to the normal control group. Liver histologic analysis further revealed a high dose of dictamnine on female mice caused hepatocyte vesicular steatosis characterized by hepatocyte microvesicles around the liver lobules. The expressed genes, proteins, and metabolites exhibited strong associations with lipid metabolism disorder and oxidative stress. Dictamnine caused increased oxidative stress and early hepatic apoptosis via up-regulation of glutathione S transferase a1 (GSTA1) and Bax/Bcl-2 ratio and down-regulation of the antioxidative enzymes superoxide dismutase (SOD), catalase, and glutathione peroxidase 1 (GPx-1). Besides, the up-regulation of Acyl-CoA synthetase long-chain family member 4 (ACSL4) and down-regulation of acetyl-coa acetyltransferase 1 (ACAT1) and fatty acid binding protein 1 (FABP-1) proteins were linked to lipid metabolism disorder. In summary, dictamnine induces dose-dependent hepatotoxicity in mice, which impairs lipid metabolism and aggravates oxidative stress.