Evaluation of the antiproliferative effects of the HASPIN inhibitor CHR-6494 in breast cancer cell lines.

Hisayo Nishida-Fukuda,Keizo Tokuhiro,Yukio Ando,Hiroaki Matsushita,Hiromitsu Tanaka,Morimasa Wada,Daniela Cimini

doi:10.1371/journal.pone.0249912

Hisayo Nishida-Fukuda, Keizo Tokuhiro + Show 5 more

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https://doi.org/10.1371/journal.pone.0249912

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Abstract

HASPIN is a serine/threonine kinase that regulates mitosis by phosphorylating histone H3 at threonine 3. The expression levels of HASPIN in various cancers are associated with tumor malignancy and poor survival, suggesting that HASPIN inhibition may suppress cancer growth. As HASPIN mRNA levels are elevated in human breast cancer tissues compared with adjacent normal tissues, we examined the growth-suppressive effects of CHR-6494, a potent HASPIN inhibitor, in breast cancer cell lines in vitro and in vivo. We found that HASPIN was expressed in breast cancer cells of all molecular subtypes, as well as in immortalized mammary epithelial cells. HASPIN expression levels appeared to be correlated with the cell growth rate but not the molecular subtype of breast cancer. CHR-6494 exhibited potent antiproliferative effects against breast cancer cell lines and immortalized mammary epithelial cells in vitro, but failed to inhibit the growth of MDA-MB-231 xenografted tumors under conditions that have significant effects in a colorectal cancer model. These results imply that CHR-6494 does have antiproliferative effects in some situations, and further drug screening efforts are anticipated to identify more potent and selective HASPIN inhibition for use as an anticancer agent in breast cancer patients.

Highlights

Haploid germ cell-specific nuclear protein kinase (HASPIN), known as germ cell-specific gene 2 (GSG2), was first discovered in germ cells of male mice and is highly conserved in eukaryotic organisms
HASPIN was expressed in normal mammary epithelial cells and all of the breast cancer cell lines tested, and the expression levels of HASPIN were not associated with any breast cancer subtypes (Fig 2B)
HASPIN is expressed in proliferating cells but not in non-dividing cells [9], the current knowledge of HASPIN function does not provide a mechanism by which the elevated expression of HASPIN would lead to enhance cell proliferation

Summary

Introduction

Haploid germ cell-specific nuclear protein kinase (HASPIN), known as germ cell-specific gene 2 (GSG2), was first discovered in germ cells of male mice and is highly conserved in eukaryotic organisms. HASPIN possesses serine/threonine kinase activity and has been shown to phosphorylate histone H3 [1,2,3,4]. Phosphorylation of histone H3 at threonine 3 (pH3T3) by HASPIN is necessary for chromosomal passenger complex accumulation at centromeres, which is required for correct spindle-kinetochore attachment during chromosome segregation and cytokinesis [5,6,7]. RNA interference-mediated knockdown of HASPIN has been shown to inhibit cell proliferation and cause cell cycle arrest at the G2/M phase, thereby inducing apoptosis of pancreatic cancer cells [8].

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