Antitumor activity of a small-molecule inhibitor of the histone kinase Haspin

Abstract

The approval of histone deacetylase inhibitors for treatment of lymphoma subtypes has positioned histone modifications as potential targets for the development of new classes of anticancer drugs. Histones also undergo phosphorylation events, and Haspin is a protein kinase the only known target of which is phosphorylation of histone H3 at Thr3 residue (H3T3ph), which is necessary for mitosis progression. Mitotic kinases can be blocked by small drugs and several clinical trials are underway with these agents. As occurs with Aurora kinase inhibitors, Haspin might be an optimal candidate for the pharmacological development of these compounds. A high-throughput screening for Haspin inhibitors identified the CHR-6494 compound as being one promising such agent. We demonstrate that CHR-6494 reduces H3T3ph levels in a dose-dependent manner and causes a mitotic catastrophe characterized by metaphase misalignment, spindle abnormalities and centrosome amplification. From the cellular standpoint, the identified small-molecule Haspin inhibitor causes arrest in G2/M and subsequently apoptosis. Importantly, ex vivo assays also demonstrate its anti-angiogenetic features; in vivo, it shows antitumor potential in xenografted nude mice without any observed toxicity. Thus, CHR-6494 is a first-in-class Haspin inhibitor with a wide spectrum of anticancer effects that merits further preclinical research as a new member of the family of mitotic kinase inhibitors.

Phosphorylation of threonine 3 on histone H3 by Haspin kinase is required for meiosis I in mouse oocytes

“…S1). We observed similar results when oocytes were treated with the same doses of CHR-6494 (CHR) (Huertas et al, 2012), another small-molecule inhibitor of haspin (supplementary material Fig. S2A).…”

“…To our surprise, perturbation of haspin activity did not affect kinetochore-localized AURKC-CPC but specifically ablated ICA-localized AURKC-CPC. However, we Although haspin was identified as a germ-cell-specific gene expressed in mouse testes (Tanaka et al, 1999) and noted as a key regulator of the mitotic cell cycle in somatic cells Dai et al, 2009;Dai et al, 2006;De Antoni et al, 2012;Huertas et al, 2012;Wang et al, 2012;Yamagishi et al, 2010), its role in meiosis and specifically in oocyte meiotic maturation is still not known. To first determine whether an H3T3 kinase exists in mouse oocytes, we performed immunocytochemistry using an antibody that recognizes phosphorylated H3T3 (H3pT3) on in-vitro-matured oocytes fixed at different stages of meiotic maturation.…”

“…Haspin activity is required for meiotic progression Inhibition of haspin in somatic cells causes a host of phenotypic consequences, including prolonged length of time to anaphase onset, chromosome misalignment and lagging chromosomes Dai et al, 2006;De Antoni et al, 2012;Huertas et al, 2012;Markaki et al, 2009;Wang et al, 2012;Yamagishi et al, 2010). To determine whether haspin activity is required for oocyte meiotic maturation, we matured oocytes in 5-iodotubercidin (5-Itu), a small-molecule inhibitor with high specificity for haspin (De Antoni et al, 2012;Wang et al, 2012).…”

Genetic Variation in the Testis-Specific HASPIN Gene Encoding a Serine/Threonine Protein Kinase in Infertile Japanese Males

“…Recently, in a kinase inhibitor screen using a histone H3 assay with a high-throughput radiometric enzymatic HASPIN kinase, the CHR-6494 compound was identified as a HASPIN kinase inhibitor. CHR-6494 was shown to exhibit antitumor activity [11]. In addition, disordered HASPIN expression was found to arrest cell division [12] [13].…”

siRNA screening of the kinome identified Aurora A kinase as a therapeutic target gene in cervical cancer

“…In addition, little is known about Haspin and, in fact, the relation between Haspin and cervical cancer was never built. However, a small molecule inhibitor developed by Chroma Therapeutics called (CHR-6494) was used in a panel of cell lines including HeLa and showed promising results by decreasing the viability of HeLa and some other cancer cell lines (Huertas et al, 2012). Therefore, Haspin is an interesting area that worth investigation using small molecule inhibitors and siRNA.…”