AZ505

AZ505, a molecule identified from a high throughput chemical screen, is a potent and selective inhibitor of SET and MYND domain-containing 2 protein (SMYD2), a protein lysine methyltransferase catalyzing the methylation of both histone (H2B, H3 and H4) and non-histone protein substrates including the tumor suppressor proteins p53 and Rb, with the half maximal inhibition concentration IC50 and inhibition constant Ki values of 0.12 μM and 0.3 μM respectively [1].
AZ505 has been found to be a substrate competitive inhibitor of SMYD2, where it binds into the peptide binding groove of SMYD2 competing with the peptide substrates rather than the co-factor [1].
References:
[1] Ferguson AD, Larsen NA, Howard T, Pollard H, Green I, Grande C, Cheung T, Garcia-Arenas R, Cowen S, Wu J, Godin R, Chen H, Keen N. Structural basis of substrate methylation and inhibition of SMYD2. Structure. 2011 Sep 7;19(9):1262-73. doi: 10.1016/j.str.2011.06.011. Epub 2011 Jul 21.

Lysine methyltransferase SMYD2 promotes triple negative breast cancer progression.[Pubmed:29487338]

Cell Death Dis. 2018 Feb 27;9(3):326.

We identified SMYD2, a SMYD (SET and MYND domain) family protein with lysine methyltransferase activity, as a novel breast cancer oncogene. SMYD2 was expressed at significantly higher levels in breast cancer cell lines and in breast tumor tissues. Silencing of SMYD2 by RNAi in triple-negative breast cancer (TNBC) cell lines or inhibition of SMYD2 with its specific inhibitor, AZ505, significantly reduced tumor growth in vivo. SMYD2 executes this activity via methylation and activation of its novel non-histone substrates, including STAT3 and the p65 subunit of NF-kappaB, leading to increased TNBC cell proliferation and survival. There are cross-talk and synergistic effects among SMYD2, STAT3, and NF-kappaB in TNBC cells, in that STAT3 can contribute to the modification of NF-kappaB p65 subunit post-translationally by recruitment of SMYD2, whereas the p65 subunit of NF-kappaB can also contribute to the modification of STAT3 post-translationally by recruitment of SMYD2, leading to methylation and activation of STAT3 and p65 in these cells. The expression of SMYD2 can be upregulated by IL-6-STAT3 and TNFalpha-NF-kappaB signaling, which integrates epigenetic regulation to inflammation in TNBC development. In addition, we have identified a novel SMYD2 transcriptional target gene, PTPN13, which links SMYD2 to other known breast cancer associated signaling pathways, including ERK, mTOR, and Akt signaling via PTPN13 mediated phosphorylation.

Lysine methyltransferase SMYD2 promotes cyst growth in autosomal dominant polycystic kidney disease.[Pubmed:28604386]

J Clin Invest. 2017 Jun 30;127(7):2751-2764.

Autosomal dominant polycystic kidney disease (ADPKD) is driven by mutations in PKD1 and PKD2 genes. Recent work suggests that epigenetic modulation of gene expression and protein function may play a role in ADPKD pathogenesis. In this study, we identified SMYD2, a SET and MYND domain protein with lysine methyltransferase activity, as a regulator of renal cyst growth. SMYD2 was upregulated in renal epithelial cells and tissues from Pkd1-knockout mice as well as in ADPKD patients. SMYD2 deficiency delayed renal cyst growth in postnatal kidneys from Pkd1 mutant mice. Pkd1 and Smyd2 double-knockout mice lived longer than Pkd1-knockout mice. Targeting SMYD2 with its specific inhibitor, AZ505, delayed cyst growth in both early- and later-stage Pkd1 conditional knockout mouse models. SMYD2 carried out its function via methylation and activation of STAT3 and the p65 subunit of NF-kappaB, leading to increased cystic renal epithelial cell proliferation and survival. We further identified two positive feedback loops that integrate epigenetic regulation and renal inflammation in cyst development: SMYD2/IL-6/STAT3/SMYD2 and SMYD2/TNF-alpha/NF-kappaB/SMYD2. These pathways provide mechanisms by which SMYD2 might be induced by cyst fluid IL-6 and TNF-alpha in ADPKD kidneys. The SMYD2 transcriptional target gene Ptpn13 also linked SMYD2 to other PKD-associated signaling pathways, including ERK, mTOR, and Akt signaling, via PTPN13-mediated phosphorylation.

The lysine methyltransferase SMYD2 methylates the kinase domain of type II receptor BMPR2 and stimulates bone morphogenetic protein signaling.[Pubmed:28588028]

J Biol Chem. 2017 Jul 28;292(30):12702-12712.

Lysine methylation of chromosomal and nuclear proteins is a well-known mechanism of epigenetic regulation, but relatively little is known about the role of this protein modification in signal transduction. Using an RNAi-based functional screening of the SMYD family of lysine methyltransferases (KMTs), we identified SMYD2 as a KMT essential for robust bone morphogenic protein (BMP)- but not TGFbeta-induced target gene expression in HaCaT keratinocyte cells. A role for SMYD2 in BMP-induced gene expression was confirmed by shRNA knockdown and CRISPR/Cas9-mediated knock-out of SMYD2 We further demonstrate that SMYD2 knockdown or knock-out impairs BMP-induced phosphorylation of the signal-transducing protein SMAD1/5 and SMAD1/5 nuclear localization and interaction with SMAD4. The SMYD2 KMT activity was required to facilitate BMP-mediated signal transduction, as treatment with the SMYD2 inhibitor AZ505 suppressed BMP2-induced SMAD1/5 phosphorylation. Furthermore, we present evidence that SMYD2 likely modulates the BMP response through its function in the cytosol. We show that, although SMYD2 interacted with multiple components in the BMP pathway, it specifically methylated the kinase domain of BMP type II receptor BMPR2. Taken together, our findings suggest that SMYD2 may promote BMP signaling by directly methylating BMPR2, which, in turn, stimulates BMPR2 kinase activity and activation of the BMP pathway.

Structural basis of substrate methylation and inhibition of SMYD2.[Pubmed:21782458]

Structure. 2011 Sep 7;19(9):1262-73.

Protein lysine methyltransferases are important regulators of epigenetic signaling. These enzymes catalyze the transfer of donor methyl groups from S-adenosylmethionine to specific acceptor lysines on histones, leading to changes in chromatin structure and transcriptional regulation. These enzymes also methylate nonhistone protein substrates, revealing an additional mechanism to regulate cellular physiology. The oncogenic protein SMYD2 represses the functional activities of the tumor suppressor proteins p53 and Rb, making it an attractive drug target. Here we report the discovery of AZ505, a potent and selective inhibitor of SMYD2 that was identified from a high throughput chemical screen. We also present the crystal structures of SMYD2 with p53 substrate and product peptides, and notably, in complex with AZ505. This substrate competitive inhibitor is bound in the peptide binding groove of SMYD2. These results have implications for the development of SMYD2 inhibitors, and indicate the potential for developing novel therapies targeting this target class.