Pimozide suppresses cancer cell migration and tumor metastasis through binding to ARPC2, a subunit of the Arp2/3 complex

Abstract

ARPC2 is a subunit of the Arp2/3 complex, which is essential for lamellipodia, invadopodia and filopodia, and ARPC2 has been identified as a migrastatic target molecule. To identify ARPC2 inhibitors, we generated an ARPC2 knockout DLD‐1 human colon cancer cell line using the clustered regularly interspaced short palindromic repeats/CRISPR‐associated protein 9 (CRISPR/Cas9) system and explored gene signature‐based strategies, such as a connectivity map (CMap) using the gene expression profiling data of ARPC2 knockout and knockdown cells. From the CMap‐based drug discovery strategy, we identified pimozide (a clinically used antipsychotic drug) as a migrastatic drug and ARPC2 inhibitor. Pimozide inhibited the migration and invasion of various cancer cells. Through drug affinity responsive target stability (DARTS) analysis and cellular thermal shift assay (CETSA), it was confirmed that pimozide directly binds to ARPC2. Pimozide increased the lag phase of Arp2/3 complex‐dependent actin polymerization and inhibited the vinculin‐mediated recruitment of ARPC2 to focal adhesions in cancer cells. To validate the likely binding of pimozide to ARPC2, mutant cells, including ARPC2F225A, ARPC2F247A and ARPC2Y250F cells, were prepared using ARPC2 knockout cells prepared by gene‐editing technology. Pimozide strongly inhibited the migration of mutant cells because the mutated ARPC2 likely has a larger binding pocket than the wild‐type ARPC2. Therefore, pimozide is a potential ARPC2 inhibitor, and ARPC2 is a new molecular target. Taken together, the results of the present study provide new insights into the molecular mechanism and target that are responsible for the antitumor and antimetastatic activity of pimozide.

Targeting the cytoskeleton against metastatic dissemination

“…Through a Connectivity Map (CMap)-based drug discovery strategy as a new screening method, Choi and co-workers identified pimozide, an antipsychotic drug used in the clinic, as an ARPC2 inhibitor [374]. This compound has been shown to strongly impair migrating and invasive abilities of different cancer cells.…”

Repurposing of Drug Candidates for Treatment of Skin Cancer

“…Pimozide is an antagonist for dopamine receptors; it is employed to treat Gilles de la Tourette syndrome and schizophrenia ( 84 ). Additionally, pimozide has shown promising results for managing several cancers, including skin cancer ( 36 , 85 – 87 ). An early clinical trial showed that pimozide might have beneficial effects in patients with formerly medicated metastatic melanoma ( 86 ).…”

“…An early clinical trial showed that pimozide might have beneficial effects in patients with formerly medicated metastatic melanoma ( 86 ). The possible molecular mechanism for this anti-metastatic effect could be mediated by inhibition of ARPC2, a subunit of the Arp2/3 complex involved in migration and invasion ( 85 ). Moreover, preclinical studies demonstrated that the combination of pimozide with other drugs might enhance its anti-melanoma activity.…”

Involvement of Actin and Actin-Binding Proteins in Carcinogenesis

“…Inhibition of the Arp2/3 complex in glioblastoma cells resulted in the loss of cell lamellipodia and polarity, which was associated with reduced migration and invasion [ 57 ]. Furthermore, Choi et al presented the possibility of limiting the migration and invasion of cancer cells (lung, pancreas, and colon) by blocking the function of ARPC2 using pimozide [ 104 ].…”