Abstract Acetyl-CoA Carboxylase Research Articles

Abstract 1573: Inhibition of acetyl-CoA carboxylase induced spindle abnormalities

Abstract Acetyl-CoA carboxylase (ACC), the rate-limiting enzyme in the de novo fatty acid synthesis pathway, is required for successful cell division in yeast, indicating that fatty acid synthesis may be regulated in order to properly safeguard nuclear and cell division. ACC is also phosphorylated during mitosis and this inhibitory phospho-ACC is accumulated at the spindle pole at metaphases. In this study, we set out to understand the role of ACC in the regulation of mitotic spindle assembly in human cells. We found that inhibition of ACC with TOFA induced spindle defects and cell death. The spindle defects induced by TOFA could be rescued by exogenous palmitic acid (PA), the immediate products of fatty acid synthesis. Inhibiting protein palmitoylating or depalmitoylating enzymes could induced spindle defects. These data indicate that well-regulated cellular PA levels and protein palmitoylation are required to assure accurate spindle assembly. In addition, the spindle microtubules comprised of α-tubulins mutated at the reported palmitoylation site exhibited disrupted dynamic instability. These results reveal that ACC may modulate tubulin palmitoylation during mitosis to delicately control MT dynamic instability and spindle assembly, thereby safeguarding nuclear and cell division. Citation Format: Chieh-Ting Fang, Hsiao-Hui Kuo, Sih-Long Liu, Jhong-Syuan Yao, Ling-Huei Yih. Inhibition of acetyl-CoA carboxylase induced spindle abnormalities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1573.

Synthesis and biological evaluation of 4-phenoxy-phenyl isoxazoles as novel acetyl-CoA carboxylase inhibitors

Acetyl-CoA carboxylase (ACC) is a crucial enzyme in fatty acid metabolism, which plays a major role in the occurrence and development of certain tumours. Herein, one potential ACC inhibitor (6a) was identified through high-throughput virtual screening (HTVS), and a series of 4-phenoxy-phenyl isoxazoles were synthesised for structure-activity relationship (SAR) studies. Among these compounds, 6g exhibited the most potent ACC inhibitory activity (IC50=99.8 nM), which was comparable to that of CP-640186. Moreover, the antiproliferation assay revealed that compound 6l exhibited the strongest cytotoxicity, with IC50 values of 0.22 µM (A549), 0.26 µM (HepG2), and 0.21 µM (MDA-MB-231), respectively. The preliminary mechanistic studies on 6g and 6l suggested that the compounds decreased the malonyl-CoA levels, arrested the cell cycle at the G0/G1 phase, and induced apoptosis in MDA-MB-231 cells. Overall, these results indicated that the 4-phenoxy-phenyl isoxazoles are potential for further study in cancer therapeutics as ACC inhibitors.

Inhibition of Acetyl-CoA Carboxylase Causes Malformations in Rats and Rabbits: Comparison of Mammalian Findings and Alternative Assays.

Acetyl-CoA carboxylase (ACC) is an enzyme within the de novo lipogenesis (DNL) pathway and plays a role in regulating lipid metabolism. Pharmacologic ACC inhibition has been an area of interest for multiple potential indications including oncology, acne vulgaris, metabolic diseases such as type 2 diabetes mellitus, and nonalcoholic fatty liver disease/nonalcoholic steatohepatitis. A critical role for ACC in de novo synthesis of long-chain fatty acids during fetal development has been demonstrated in studies in mice lacking Acc1, where the absence of Acc1 results in early embryonic lethality. Following positive predictions of developmental toxicity in the alternative in vitro assays (positive in murine embryonic stem cell [mESC] assay and rat whole embryo culture, but negative in zebrafish), developmental toxicity (growth retardation and dysmorphogenesis associated with disrupted midline fusion) was observed with the oral administration of the dual ACC1 and 2 inhibitors, PF-05175157, in Sprague Dawley rats and New Zealand White rabbits. The results of these studies are presented here to make comparisons across the assays, as well as mechanistic insights from the mESC assay demonstrating high ACC expression in the mESC and that ACC-induced developmental toxicity can be rescued with palmitic acid providing supportive evidence for DNL pathway inhibition as the underlying mechanism. Ultimately, while the battery of alternative approaches and weight-of-evidence case were useful for hazard identification, the embryo-fetal development studies were necessary to inform the risk assessment on the adverse fetal response, as malformations and/or embryo-fetal lethality were limited to doses that caused near-complete inhibition of DNL.

Molecular modeling study for the design of novel acetyl-CoA carboxylase inhibitors using 3D QSAR, molecular docking and dynamic simulations

Acetyl-CoA carboxylase (ACC) enzyme plays an important role in the regulation of biosynthesis and oxidation of fatty acids. ACC is a recognized drug target for the treatment of obesity and diabetes. Combination of ligand and structure-based in silico methods along with activity and toxicity prediction provides best lead compounds in the drug discovery process. In this study, a data-set of 100 ACC inhibitors were used for the development of comparative molecular field analysis (CoMFA) and comparative molecular similarity index matrix analysis (CoMSIA) models. The generated contour maps were used for the design of novel ACC inhibitors. CoMFA and CoMSIA models were used for the predication of activity of designed compounds. In silico toxicity risk prediction study was carried out for the designed compounds. Molecular docking and dynamic simulations studies were performed to know the binding mode of designed compounds with the ACC enzyme. The designed compounds showed interactions with key amino acid residues important for catalysis, and good correlation was observed between binding free energy and inhibition of ACC.

Identification of dual Acetyl-CoA carboxylases 1 and 2 inhibitors by pharmacophore based virtual screening and molecular docking approach

Acetyl-CoA carboxylase (ACC) is a crucial metabolic enzyme that plays a vital role in obesity-induced type 2 diabetes and fatty acid metabolism. To identify dual inhibitors of Acetyl-CoA carboxylase1 and Acetyl-CoA carboxylase2, a pharmacophore modelling approach has been employed. The best HypoGen pharmacophore model for ACC2 inhibitors (Hypo1_ACC2) consists of one hydrogen bond acceptor, one hydrophobic aliphatic and one hydrophobic aromatic feature, whereas the best pharmacophore (Hypo1_ACC1) for ACC1 consists of one additional hydrogen-bond donor (HBD) features. The best pharmacophore hypotheses were validated by various methods such as test set, decoy set and Cat-Scramble methodology. The validated pharmacophore models were used to screen several small-molecule databases, including Specs, NCI, ChemDiv and Natural product databases to identify the potential dual ACC inhibitors. The virtual hits were then subjected to several filters such as estimated [Formula: see text] value, quantitative estimation of drug-likeness and molecular docking analysis. Finally, three novel compounds with diverse scaffolds were selected as potential starting points for the design of novel dual ACC inhibitors.

Targeting Acetyl-CoA Carboxylase to Stay Lean

Acetyl-CoA carboxylase (ACC) regulates synthesis and oxidation of fatty acids, and mice lacking the ACC2 isoform are leaner than wild-type animals. Choi et al . further characterized whole-body energy metabolism and insulin sensitivity of Acc2 –/– mice and obtained results supporting the possibility of ACC2 inhibitors as agents to treat obesity and type 2 diabetes. By monitoring activity of the animals, food consumption, and energy expenditure, the authors showed that Acc2 –/– animals ate more food than did wild-type animals but were still leaner than the control animals. The Acc2 –/– animals were also resistant to obesity brought on by eating a diet high in fats. These effects could be explained by the increase in energy expenditure that was observed in the knockout animals. Although oxidation of fats and of carbohydrates have been thought to be mutually exclusive (thus providing an explanation for insulin resistance observed in animals with excess fatty acids), Choi et al . found that oxidation of both fats and carbohydrates was increased in the Acc2 –/– animals. Insulin responsiveness was also enhanced in the knockout animals. Resistance to insulin that occurs with fat accumulation is thought to result from accumulation of diacylglycerol in muscle and liver and consequent activation of protein kinase C (PKC) θ and PKCε in muscle and liver, respectively. In the Acc2 –/– mice, enhanced sensitivity to insulin was associated with decreased activity of the PKC enzymes. ACC2 is not a particularly easy target for development of therapeutics in that the ACC1 isoform is required for viability during embryogenesis. Nevertheless, the authors propose, the properties of the Acc2 –/– animals show that patients with common diseases like diabetes and obesity could be helped by continued efforts to develop a specific inhibitor for ACC2. C. S. Choi, D. B. Savage, L. Abu-Elheiga, Z.-X. Liu, S. Kim, A. Kulkarni, A. Distefano, Y.-J. Hwang, R. M. Reznick, R. Codella, D. Zhang, G. W. Cline, S. J. Wakil, G. I. Shulman, Continuous fat oxidation in acetyl-CoA carboxylase 2 knockout mice increases total energy expenditure, reduces fat mass, and improves insulin sensitivity. Proc. Natl. Acad. Sci. U.S.A . 104 , 16480-16485 (2007). [Abstract] [Full Text]

Cyclohexanedione herbicides are inhibitors of rat heart acetyl-CoA carboxylase.

Acetyl CoA carboxylase (ACC) catalyzes the carboxylation of acetyl CoA to form malonyl CoA. In skeletal muscle and heart, malonyl CoA functions to regulate lipid oxidation by inhibition of carnitine palmitoyltransferase-1, an enzyme which controls the entry of long chain fatty acids into mitochondria. We have found that several members of the cyclohexanedione class of herbicides are competitive inhibitors of rat heart ACC. These compounds constitute valuable reagents for drug development and the study of ACCbeta, a validated anti-obesity target.

Age-related changes in rat hepatic acetyl-coenzyme A carboxylase.

Acetyl-CoA carboxylase (ACC) catalyzes the rate-limiting step in the synthesis of long-chain fatty acids. Since aging influences adiposity, we studied the activity of ACC and its mRNA content in livers of 4-, 12-, and 24-month-old male Fischer 344 rats. The mean (+/- SEM) activity of ACC (mU/mg protein) in liver homogenates from 4-month-old rats was 1.01 +/- 0.14. There was an 80% increase in activity (1.83 +/- 0.27) in 12-month-old rats (P < 0.01). However, there was significantly less activity (0.46 +/- 0.06) in livers of 24-month-old rats (P < 0.001). The total activity of ACC (per g liver) followed the same trend. The enzyme from all age groups was purified by avidin-affinity chromatography. The purified preparation migrated as a major protein band (M(r) 262,000) on sodium dodecyl sulfate (SDS)-polyacrylamide gels. The specific activity of the purified preparation was 1.5, 1.8, and 1.8 U/mg for 4-, 12-, and 24-month-old rats, respectively. The alkali-labile phosphate content was 5.66 +/- 0.17, 5.64 +/- 0.21, and 6.21 +/- 0.35 mols P(i)/mole subunit for 4-, 12-, and 24-month-old rats, respectively. These age-related differences were not significant. The hepatic ACC mRNA measured by ribonuclease protection assay when corrected for G3PDH mRNA was significantly reduced in 24-month-old rats (0.24 +/- 0.03) compared with 12-month-old (0.58 +/- 0.04) or 4-month-old rats (0.43 +/- 0.007) P < 0.01. In summary: (i) Aging in rats is associated with significant changes in ACC activity; (ii) the purified ACC preparations from the three age groups had similar specific activity and similar phosphate content; and (iii) the changes in ACC mRNA content of the liver paralleled the changes in total enzyme activity when 12-month-old rats were compared with 24-month-old rats whereas the increase in ACC activity in 12-month-old rats compared with 4-month-old rats could not be ascribed to changes in hepatic mRNA levels. These results indicate that the age-related changes in hepatic ACC occur at a post-translational level during early years of aging and at a pretranslational level at late states of senescence. These changes may contribute to the age-related alterations in body adiposity.

Acetyl-CoA carboxylase mRNA species with or without inhibitory coding sequence for Ser-1200 phosphorylation.

Acetyl-CoA carboxylase (ACC) is the rate-limiting enzyme in the biogenesis of long chain fatty acids. The phosphorylation of the Ser-1200 residue by cyclic AMP-dependent protein kinase transforms ACC from a citrate-independent form to a citrate-dependent form (10, 16). We have isolated ACC cDNA clones with and without 24 bases which code for 8 additional amino acids located 4 residues upstream to the Ser-1200. The presence of the 8 extra amino acids inhibits the in vitro phosphorylation of the Ser-1200 by the catalytic subunit of cyclic AMP-dependent protein kinase. The S1 nuclease protection experiments indicate that the corresponding two ACC mRNA species occur in vivo. Furthermore, the occurrence of the two forms of ACC mRNA is regulated under different physiological conditions for lipogenesis in a tissue-specific manner. The existence of two forms of ACC mRNA provides the basis for the existence of isozymes of ACC whose Ser-1200 can be selectively phosphorylated. The location of this regulatory sequence for a specific phosphorylation site represents a new regulatory mechanism for protein phosphorylation.