Caspase-3/7 Inhibitor I

Caspase-3/7 inbibitor I is a potent, reversible, isatin sulfonamide-based inhibitor of caspase-3 (KI(app) = 60 nM) and caspase-7 (KI(app) = 170 nM). Is a weaker inhibitor of caspase-9 (Ki(app) = 3.1 mM). It Has only a trivial effect (Ki(app) >25 mM) on the activities of caspase-1, caspase-2, caspase-4, caspase-6, and caspase-8. It has been shown to inhibit apoptosis in camptothecin treated Jurkat cells (IC50 ~50 µM). Also it has been reported to inhibit apoptosis in chondrocytes (44% inhibition at 10 µM and 98% inhibition at 50 µM). Selectivity for caspases-3 and 7 involves unique hydrophobic residues in the S2 pocket surrounding the catalytic cysteine residue. [1] [2] In some systems inhibition of caspases-3 and -7 can prevent apoptosis and may therefore have important therapeutic implications. [3]

A potent, cell-permeable, and specific, reversible inhibitor of caspase-3 (Ki = 60 nM) and caspase-7 (Ki = 170 nM).

References:
1. Lee, D., et al. 2001. J. Med. Chem. 44, 2015.
2. Lee, D., et al. 2000. J. Biol. Chem. 275, 16007.
3. Clements, K. M., Burton‐Wurster, N., Nuttall, M. E., & Lust, G. (2005). Caspase‐3/7 inhibition alters cell morphology in mitomycin‐c treated chondrocytes. Journal of cellular physiology, 205(1), 133-140.

Synthesis of 7-halogenated isatin sulfonamides: nonradioactive counterparts of caspase-3/-7 inhibitor-based potential radiopharmaceuticals for molecular imaging of apoptosis.[Pubmed:25358116]

J Med Chem. 2014 Nov 26;57(22):9383-95.

N-Alkylated (S)-7-halogen-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatins were developed as a new group of nonradioactive reference compounds for future radiotracers. Inhibitor potency studies of these compounds suggest that the binding pockets readily accommodate both the 7-halogen substituents and aliphatic side chains (methyl to n-butyl) as well as some omega-fluorinated analogues (3-fluoropropyl and 4-fluorobutyl) at the isatin nitrogen. Indeed, compared to the halogen free parent compounds, some 7-halogenated derivatives exhibited slightly improved inhibitory potencies with IC50 values up to 2.6 nM (caspase-3) and 3.3 nM (caspase-7), respectively. Moreover, the 7-position of isatin, a potential cytochrome P450 hydroxylation site, was substituted by I, Br, Cl, and F to potentially enhance the metabolic stability of isatin sulfonamides. As an example, the radiotracer [(18)F]39 that was produced by (19)F/(18)F isotope exchange was shown to be stable in human blood serum after incubation at 37 degrees C for at least 90 min.

A novel nonpeptidic caspase-3/7 inhibitor, (S)-(+)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin reduces myocardial ischemic injury.[Pubmed:12450570]

Eur J Pharmacol. 2002 Dec 5;456(1-3):59-68.

The efficacy of a novel, nonpeptidic, caspase 3/7-selective inhibitor, (S)-(+)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin (MMPSI) for reducing ischemic injury in isolated rabbit hearts or cardiomyocytes was evaluated. MMPSI (0.1-10 microM) evoked a concentration-dependent reduction in infarct size (up to 56% vs. control; IC(50)=0.2 microM). Furthermore, apoptosis (DNA laddering, soluble nucleosomes) was reduced in the ischemic area-at-risk. MMPSI inhibited recombinant human caspase-3 with an IC(50)=1.7 microM. Apoptosis in H9c2 cells after 16-h simulated ischemia and 2-h simulated reperfusion was significantly reduced by MMPSI in a concentration-dependent manner (IC(50)=0.5 microM); similar effects were observed in isolated adult rabbit cardiomyocytes (IC(50)=1.5 microM). These data support an important role for caspase-3/7 in mediating myocardial ischemic injury. Furthermore, these data indicate that cardioprotection via caspase-3/7 inhibition is attainable via a small molecule (nonpeptidic) inhibitor, a necessary step in making this approach therapeutically viable.

Combination of the histone deacetylase inhibitor depsipeptide and 5-fluorouracil upregulates major histocompatibility complex class II and p21 genes and activates caspase-3/7 in human colon cancer HCT-116 cells.[Pubmed:27509880]

Oncol Rep. 2016 Oct;36(4):1875-85.

Epigenetic anticancer drugs such as histone deacetylase (HDAC) inhibitors have been combined with existing anticancer drugs for synergistic or additive effects. In the present study, we found that a very low concentration of depsipeptide, an HDAC inhibitor, potentiated the antitumor activity of 5-fluorouracil (5-FU) in a human colon cancer cell model using HCT-116, HT29, and SW48 cells via the inhibition of colony formation ability or cellular viability. Exposure to a combination of 5-FU (1.75 microM) and 1 nM depsipeptide for 24 and 48 h resulted in a 3- to 4-fold increase in activated caspase-3/7, while 5-FU alone failed to activate caspase-3/7. Microarray and subsequent gene ontology analyses revealed that compared to 5-FU or depsipeptide alone, the combination treatment of 5-FU and depsipeptide upregulated genes related to cell death and the apoptotic process consistent with the inhibition of colony formation and caspase-3/7 activation. These analyses indicated marked upregulation of antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class (GO:0002504) and MHC protein complex (GO:0042611). Compared with vehicle controls, the cells treated with the combination of 5-FU and depsipeptide showed marked induction (3- to 8.5-fold) of expression of MHC class II genes, but not of MHC class I genes. Furthermore, our global analysis of gene expression, which was focused on genes involved in the molecular regulation of MHC class II genes, showed enhancement of pro-apoptotic PCAF and CIITA after the combination of 5-FU and depsipeptide. These results may indicate a closer relationship between elevation of MHC class II expression and cellular apoptosis induced by the combination of depsipeptide and 5-FU. To the best of our knowledge, this is the first study to report that the combination of 5-FU and depsipeptide induces human colon cancer cell apoptosis in a concerted manner with the induction of MHC class II gene expression.