NH-11

Amino Acid Sequence

3D Structure (/structures/AF-P43490-F1-model_v6.cif)

Function

Catalyzes the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to yield nicotinamide mononucleotide, an intermediate in the biosynthesis of NAD. It is the rate limiting component in the mammalian NAD biosynthesis pathway. The secreted form behaves both as a cytokine with immunomodulating properties and an adipokine with anti-diabetic properties, it has no enzymatic activity, partly because of lack of activation by ATP, which has a low level in extracellular space and plasma. Plays a role in the modulation of circadian clock function. NAMPT-dependent oscillatory production of NAD regulates oscillation of clock target gene expression by releasing the core clock component: CLOCK-BMAL1 heterodimer from NAD-dependent SIRT1-mediated suppression.

Mechanism

The ubiquitin-proteasome pathway (UPP) constitutes the principal pathway for protein degradation in eukaryotic cells, mediating the breakdown of target proteins through ubiquitin tagging and subsequent proteasomal degradation. In an ATP-dependent manner, the ubiquitin-activating enzyme (E1) activates ubiquitin (Ub) and conjugates it to a ubiquitin-conjugating enzyme (E2). E3 ligase subsequently catalyzes the transfer of Ub to the target protein, leading to the formation of a polyubiquitin chain that completes the ubiquitination mark. The 19S regulatory particle of the 26S proteasome recognizes this ubiquitination signal and, after deubiquitination, mediates the ATP-dependent delivery of the substrate into the 20S proteasome for degradation.

Description

Compound NH-11 possessed the highest capacity for NAMPT degradation and was selected for further mechanism and antitumor activity evaluations. In eukaryotic cells, damaged proteins can be degraded by proteasomes or lysosomes [35,36]. To investigate the potential degradation mechanism of NH-11, we performed rescue assays. The K562 cells was co-treated with NH-11 and lysosomal inhibitor bafilomycin A1 (Baf A1) [37], or ubiquitin (Ub) proteasome inhibitors MG132 [38], carfilzomib [39]. It was found that the MG132 and carfilzomib largely abolished NH-11-induced NAMPT degradation (Fig. 3E), indicating that NH-11 mediated the degradation of NAMPT via the Ub-proteasome system (UPS).

Description

NH-11 dose-dependently induced NAMPT degradation with DC 50 values of 3.18 μmol/L (K562), 6.05 μmol/L (HL60) and 7.32 μmol/L (Jurkat), respectively (Figs. 3A and B)

Description

NH-11 dose-dependently induced NAMPT degradation with DC 50 values of 3.18 μmol/L (K562), 6.05 μmol/L (HL60) and 7.32 μmol/L (Jurkat), respectively (Figs. 3A and B)

Description

NH-11 dose-dependently induced NAMPT degradation with DC 50 values of 3.18 μmol/L (K562), 6.05 μmol/L (HL60) and 7.32 μmol/L (Jurkat), respectively (Figs. 3A and B)

Description

Given the potent NAMPT inhibition activity and degradation efficiency of NH-11, its antiproliferative activity against leukemia cell lines were also investigated by using a cell counting kit-8 (CCK8) assay. The results revealed that NH-11 showed potent antiproliferative activity against K562, Jurkat and HL60 cells with IC50 value of 0.73 ± 0.31, 0.03 ± 0.01, and 0.95 ± 0.38 μmol/L, respectively (Fig. S2 and Table S2 in Supporting information).

Description

Given the potent NAMPT inhibition activity and degradation efficiency of NH-11, its antiproliferative activity against leukemia cell lines were also investigated by using a cell counting kit-8 (CCK8) assay. The results revealed that NH-11 showed potent antiproliferative activity against K562, Jurkat and HL60 cells with IC50 value of 0.73 ± 0.31, 0.03 ± 0.01, and 0.95 ± 0.38 μmol/L, respectively (Fig. S2 and Table S2 in Supporting information).

Description

Given the potent NAMPT inhibition activity and degradation efficiency of NH-11, its antiproliferative activity against leukemia cell lines were also investigated by using a cell counting kit-8 (CCK8) assay. The results revealed that NH-11 showed potent antiproliferative activity against K562, Jurkat and HL60 cells with IC50 value of 0.73 ± 0.31, 0.03 ± 0.01, and 0.95 ± 0.38 μmol/L, respectively (Fig. S2 and Table S2 in Supporting information).