5,5-Dimethyl-3-(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-1-phenyl-3-(trifluoromethyl)-3,5,6,7-tetrahydro-1H-indole-2,4-dione, a Potent Inhibitor for Mammalian Elongase of Long-Chain Fatty Acids Family 6: Examination of Its Potential Utility as a Pharmacological Tool

Abstract

Long-chain fatty acid elongases reside in the endoplasmic reticulum and are responsible for the rate-limiting step of the elongation of long-chain fatty acids. The elongase of long-chain fatty acids (ELOVL) family 6 (ELOVL6) is involved in the elongation of saturated and monosaturated fatty acids. Increased expression of ELOVL6 in ob/ob mice suggests a role for ELOVL6 in metabolic disorders. Furthermore, ELOVL6-deficient mice are protected from high-fat diet-induced insulin resistance, which suggests that ELOVL6 might be a new therapeutic target for diabetes. As reported previously, we developed a high-throughput screening system for fatty acid elongases and discovered lead chemicals that possess inhibitory activities against ELOVL6. In the present study, we examined in detail the biochemical and pharmacological properties of 5,5-dimethyl-3-(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-1-phenyl-3-(trifluoromethyl)-3,5,6,7-tetrahydro-1H-indole-2,4-dione (Compound-A), a potent inhibitor of ELOVL6. In in vitro assays, Compound-A dose-dependently inhibited mouse and human ELOVL6 and displayed more than 30-fold greater selectivity for ELOVL6 over the other ELOVL family members. In addition, Compound-A effectively reduced the elongation index of fatty acids of hepatocytes, suggesting that Compound-A penetrates the cell wall and inhibits ELOVL6. More importantly, upon oral administration to mice, Compound-A showed high plasma and liver exposure and potently reduced the elongation index of the fatty acids of the liver. This is the first study to report a potent and selective inhibitor of mammalian elongases. Furthermore, Compound-A seems to be a useful tool to further understand the physiological roles of ELOVL6 and to evaluate the therapeutic potential of an ELOVL6 inhibitor.

Phospholipid profiling identifies acyl chain elongation as a ubiquitous trait and potential target for the treatment of lung squamous cell carcinoma

“…Silencing of ELOVL6 using siRNA showed identical effects in another established human SCC cell line H2170 ( Supplementary Figure S3 ). Similar changes were observed when these and also a mouse SCC cell line, KLN205, were treated with a selective chemical ELOVL6 inhibitor, Compound A [ 10 ] (shown for PC in Figure 6 ). As ELOVL6 has a strong substrate specificity for C16:0 and C16:1, which it converts to C18:0 and C18:1 [ 8 ], respectively, we analyzed the differences in acyl chain composition of phospholipids in cancer versus non-malignant tissue in more detail by tandem MS.…”

“…For modulation of ELOVLs by RNA interference, cells were transfected with commercially available and validated siRNAs for ELOVL2 (siRNA 1: J_009531_10; siRNA 2: J_009531_11; GE Dharmacon, Lafayette, Colorado, USA), ELOVL4 (siRNA 1: s13558; siRNA 2: s13559; Life Technologies), ELOVL6 (siRNA1: s35516; siRNA2: s35518; Life Technologies) and corresponding control siRNA using Lipofectamine RNAiMAX (Life Technologies) as transfection reagent. For chemical inhibition of ELOVL6, Compound A [ 10 ] was obtained from the Centre for Drug Design and Discovery (CD3; Leuven, Belgium) and added to culture media from a 1000-fold stock solution in DMSO.…”

Elovl6 is a negative clinical predictor for liver cancer and knockdown of Elovl6 reduces murine liver cancer progression

“…A novel Elovl6 inhibitor, 5,5-dimethyl-3-(5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-1-phenyl-3-(trifluoromethyl)-3,5,6,7-tetrahydro-1H-indole-2,4-dione, has been reported. This Elovl6 inhibitor was shown to display more than 30-fold greater selectivity for Elovl6 over other Elovl family members and effectively reduced the elongation index of fatty acids of hepatocytes 17 . However, the effect of this Elovl6 inhibitor on cellular proliferation remains unclear.…”

Altered Saturated and Monounsaturated Plasma Phospholipid Fatty Acid Profiles in Adult Males with Colon Adenomas

“…SCD-1 EAE was calculated in two ways (20): SCD n-7 index (SCD n-7) = palmitoleic (POA)/PA, and SCD n-9 index (SCD n-9) = OA/SA. A variation of the Elovl-6 EAE was calculated as Elovl-6 = Σ [SA + OA]/PA (21, 22). The total PPL SFA, cis-MUFA, trans-MUFA were calculated as follows: total PPL SFA was calculated as Σ PA + SA + arachidic + behenic + lignoceric; total PPL cis-MUFA was calculated as Σ POA + eicosaenoic + nervonic (NA); total PPL trans-MUFA was calculated as Σ palmitelaidic + elaidic.…”