Characterization of the biological activity of a potent small molecule Hec1 inhibitor TAI-1

Lynn Yl Huang,Pei-Yi Tsai,Her-Sheng Lin,Jia-Ming Chang,Chia-Chi Chang,Ying-Shuan Lee,Johnson Yn Lau,Yung-Jen Tsai,Kuo-Jang Kao,Chia-Wei Liu,Shih-Hsien Chuang,Jiann-Jyh Huang

doi:10.1186/1756-9966-33-6

Abstract

BackgroundHec1 (NDC80) is an integral part of the kinetochore and is overexpressed in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. A highly potent first-in-class compound targeting Hec1, TAI-1, was identified and is characterized in this study to determine its potential as an anticancer agent for clinical utility.MethodsThe in vitro potency, cancer cell specificity, synergy activity, and markers for response of TAI-1 were evaluated with cell lines. Mechanism of action was confirmed with western blotting and immunofluorescent staining. The in vivo potency of TAI-1 was evaluated in three xenograft models in mice. Preliminary toxicity was evaluated in mice. Specificity to the target was tested with a kinase panel. Cardiac safety was evaluated with hERG assay. Clinical correlation was performed with human gene database.ResultsTAI-1 showed strong potency across a broad spectrum of tumor cells. TAI-1 disrupted Hec1-Nek2 protein interaction, led to Nek2 degradation, induced significant chromosomal misalignment in metaphase, and induced apoptotic cell death. TAI-1 was effective orally in in vivo animal models of triple negative breast cancer, colon cancer and liver cancer. Preliminary toxicity shows no effect on the body weights, organ weights, and blood indices at efficacious doses. TAI-1 shows high specificity to cancer cells and to target and had no effect on the cardiac channel hERG. TAI-1 is synergistic with doxorubicin, topotecan and paclitaxel in leukemia, breast and liver cancer cells. Sensitivity to TAI-1 was associated with the status of RB and P53 gene. Knockdown of RB and P53 in cancer cells increased sensitivity to TAI-1. Hec1-overexpressing molecular subtypes of human lung cancer were identified.ConclusionsThe excellent potency, safety and synergistic profiles of this potent first-in-class Hec1-targeted small molecule TAI-1 show its potential for clinically utility in anti-cancer treatment regimens.

Highlights

Highly Expressed in Cancer 1 (Hec1) (NDC80) is an integral part of the kinetochore and is overexpressed in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics
Hec1 inhibitor TAI-1 is highly potent with a wide anticancer spectrum The initial small molecule hits identified by Drs Chen in Dr WH Lee’s laboratory, INH1 and INH2, had micromolar potency on cancer cell lines [3,11,12]
Through medicinal chemical efforts to modify the hit structure, we have significantly improved the potency of the Hec1targeted compound to low nanomolar level

Summary

Introduction

Hec (NDC80) is an integral part of the kinetochore and is overexpressed in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. Development of chemotherapeutic drugs that target the mitotic cycle has focused on inhibition of the mitotic spindle through interactions with microtubules [1]. Drugs targeting microtubules such as taxanes and vinca alkaloids are effective in a wide variety of cancers, the hematopoietic. A novel attractive non-microtubule target is Highly Expressed in Cancer 1 (Hec1), a component of the kinetochore that regulates the spindle checkpoint. Hec directly interacts with multiple kinetochore components including Nuf, Spc, Zwint-1, and with mitotic kinases Nek and Aurora B [6,7] and its expression is tightly regulated in both normal cells and transformed cells during the cell cycle [4,8]. Hec emerges as an excellent target for treating cancer clinically

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Results

Conclusion