A screen of FDA-approved drugs identifies inhibitors of protein tyrosine phosphatase 4A3 (PTP4A3 or PRL-3)

Abstract

Protein tyrosine phosphatase 4A3 (PTP4A3 or PRL-3) is highly expressed in a variety of cancers, where it promotes tumor cell migration and metastasis leading to poor prognosis. Despite its clinical significance, small molecule inhibitors of PRL-3 are lacking. Here, we screened 1443 FDA-approved drugs for their ability to inhibit the activity of the PRL phosphatase family. We identified five specific inhibitors for PRL-3 as well as one selective inhibitor of PRL-2. Additionally, we found nine drugs that broadly and significantly suppressed PRL activity. Two of these broad-spectrum PRL inhibitors, Salirasib and Candesartan, blocked PRL-3-induced migration in human embryonic kidney cells with no impact on cell viability. Both drugs prevented migration of human colorectal cancer cells in a PRL-3 dependent manner and were selective towards PRLs over other phosphatases. In silico modeling revealed that Salirasib binds a putative allosteric site near the WPD loop of PRL-3, while Candesartan binds a potentially novel targetable site adjacent to the CX5R motif. Inhibitor binding at either of these sites is predicted to trap PRL-3 in a closed conformation, preventing substrate binding and inhibiting function.

Phosphatase and Pseudo-Phosphatase Functions of Phosphatase of Regenerating Liver 3 (PRL-3) Are Insensitive to Divalent Metals In Vitro

“…The pSKB3 plasmid is a derivative of the pET-28b vector, replacing the thrombin cleavage site with a tobacco etch virus (TEV) protease cleavage site and was a gift from Dr. Konstantin Korotkov at the University of Kentucky . Full-length human PRL-(1, 2, or 3) cDNA or HA-CBS was cloned into the pSKB3 vector using the NheI and XhoI restriction sites via T4 ligase . The HA-CBS construct was obtained from a full-length CNNM3 CBS domain-pair (residues Y301-D451, RefSeq NM_017623.5) gBlock Gene Fragment (IDT), with a human influenza hemagglutinin epitope tag fused to the N-terminus.…”

“… 51 Full-length human PRL-(1, 2, or 3) cDNA or HA-CBS was cloned into the pSKB3 vector using the NheI and XhoI restriction sites via T4 ligase. 52 The HA-CBS construct was obtained from a full-length CNNM3 CBS domain-pair (residues Y301-D451, RefSeq NM_017623.5) gBlock Gene Fragment (IDT), with a human influenza hemagglutinin epitope tag fused to the N-terminus.…”

PRL3 as a therapeutic target for novel cancer immunotherapy in multiple cancer types

“…Much work on PRL3 inhibitors has focused on computationally screening small molecule libraries to identify potential lead compounds for further in vitro validation and optimization [45,49,77,141,[144][145][146][147][148][149]155]. Rhodanine-based compounds have been of key interest after this chemotype was shown to have inhibitory activity against PRL3 through a high throughput screening of a chemical library in 2006 [141].…”

Exploiting frequent and specific expression of PRL3 in pediatric solid tumors for first-in-child use of PRL3-zumab humanized antibody

“… 18 , 19 In preclinical studies, PRL3 has been shown to play a limited role in specification of neural crest progenitors 20 and regulates cellular migration in embryonic kidneys without affecting cell viability. 21 , 22 Therefore, we hypothesize that PRL3 may likewise be expressed in a highly specific manner in developmental cancers, facilitating safe application of PRL3-zumab in these diseases. However, PRL3 expression in the developing tissues of children and its toxicity profile in pediatric patients have not yet been described.…”