Correlation of tumor growth suppression and methionine aminopetidase-2 activity blockade using an orally active inhibitor

Abstract

This laboratory and others have shown that agents that inhibit the in vitro catalytic activity of methionine aminopeptidase-2 (MetAP2) are effective in blocking angiogenesis and tumor growth in preclinical models. However, these prototype MetAP2 inhibitors are clearly not optimized for therapeutic use in the clinic. We have discovered an orally active class of MetAP2 inhibitors, the anthranilic acid sulfonamides exemplified by A-800141, which is highly specific for MetAP2. This orally bioavailable inhibitor exhibits an antiangiogenesis effect and a broad anticancer activity in a variety of tumor xenografts including B cell lymphoma, neuroblastoma, and prostate and colon carcinomas, either as a single agent or in combination with cytotoxic agents. We also have developed a biomarker assay to evaluate in vivo MetAP2 inhibition in circulating mononuclear cells and in tumors. This biomarker assay is based on the N-terminal methionine status of the MetAP2-specific substrate GAPDH in these cells. In cell cultures in vitro, the sulfonamide MetAP2 inhibitor A-800141 caused the formation of GAPDH variants with an unprocessed N-terminal methionine. A-800141 blocked tumor growth and MetAP2 activity in a similar dose-response in mouse models, demonstrating the antitumor effects seen for A-800141 are causally connected to MetAP2 inhibition in vivo. The sulfonamide MetAP2 inhibitor and GAPDH biomarker in circulating leukocytes may be used for the development of a cancer treatment.angiogenesis ͉ biomarker ͉ cancer therapy ͉ GAPDH ͉ MetAP2

Targeting PI3K in neuroblastoma

“…(Values are mean § SEM; *signiWcant diVerences between AS605240-treated and vehicle-treated mice; § signiWcant diVerence between mice treated with 5 or 20 g/g AS605240; P < .05) Immunosuppressed SCID mice have been frequently used for investigations of the in vivo pattern of xenotransplanted neuroblastoma cell lines (Sims et al 2008;Wang et al 2008). These xenograft models were also deployed to analyze the antitumoral activity of low molecular compounds (Parashar and ShaWt-Zagardo 2006;Wang et al 2008). Our comparative study used the PI3K containing SK-N-LO cells and the PI3K deWcient cell line SK-N-AS for engraftment of neuroblastoma cells in mice.…”

Methionine aminopeptidase 2 is required for HSC initiation and proliferation

“…Therefore, the pI of GAPDH could be used as a surrogate for MetAP2 N-methionine excision activity. 20 At both 18 (data not shown) and 36 hpf, 2-dimensional electrophoresis and Western blotting confirmed the pI shifting of GAPDH, hence the abnormal retention of N-terminal methionine in GAPDH and reduced metap2 activity in zebrafish embryos injected with metap2 MO or treated with fumagillin. The activity could be rescued by metap2 mRNA coinjection ( Figure 5A).…”

“…Because inhibition of MetAP2 may inhibit angiogenesis in tumors, 16,20,21 we examined the effect of metap2 knockdown on angiogenesis in our zebrafish model. In metap2 MO embryos with a Tg(fli1:gfp) transgenic background, vasculogenesis was normal ( Figure 3A).…”

“…15,16 In mammals, the family comprises MetAP1 and MetAP2, although the latter has received more attention for its binding to fumagillin and ovalicin, which are antiangiogenic and antineoplastic agents. [17][18][19][20] In addition to the N-methionine excision, MetAP2 is also known as the eukaryotic initiation factor-2␣-associated 67-kDa protein (p67) and can bind to and prevent phosphorylation of eukaryotic initiation factor-2␣ and ERK1/2 under homeostatic and pathologic stress, thereby fine-tuning the level of cellular protein synthesis and proliferation. 21 More recently, MetAP2 also has been shown to be an upstream component in the noncanonical Wnt pathway.…”

Disruption of Wnt Planar Cell Polarity Signaling by Aberrant Accumulation of the MetAP-2 Substrate Rab37

“…Affinity chromatography with biotinylated fumagillin derivatives identified the metalloprotease methionine aminopeptidase-2 (MetAP-2), one of two proteins responsible for N-terminal methionine excision (NME) in eukaryotes, as the molecular target responsible for fumagillin/TNP-470’s antiangiogenic activity (Griffith, et al, 1997; Sin, et al, 1997; Yeh, et al, 2006). This discovery has stimulated interest in the exquisite sensitivity of endothelial cells to loss of MetAP-2 activity, relative to non-endothelial cell-types and inspired development of several novel structural classes of MetAP-2 inhibitors (Arico-Muendel, et al, 2009; Marino, et al, 2007; Wang, et al, 2007; Wang, et al, 2008). …”