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BioMed Research International
Volume 2015, Article ID 705745, 21 pages
Review Article

PLK-1 Targeted Inhibitors and Their Potential against Tumorigenesis

Department of Biochemistry, Institute of Cell Differentiation and Aging, College of Medicine, Hallym University, Chuncheon, Gangwon-do 200-702, Republic of Korea

Received 27 February 2015; Revised 8 May 2015; Accepted 14 May 2015

Academic Editor: Kanjoormana A. Manu

Copyright © 2015 Shiv Kumar and Jaebong Kim. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Mitotic kinases are the key components of the cell cycle machinery and play vital roles in cell cycle progression. PLK-1 (Polo-like kinase-1) is a crucial mitotic protein kinase that plays an essential role in both the onset of G2/M transition and cytokinesis. The overexpression of PLK-1 is strongly correlated with a wide spectrum of human cancers and poor prognosis. The (si)RNA-mediated depletion of PLK-1 arrests tumor growth and triggers apoptosis in cancer cells without affecting normal cells. Therefore, PLK-1 has been selected as an attractive anticancer therapeutic drug target. Some small molecules have been discovered to target the catalytic and noncatalytic domains of PLK-1. These domains regulate the catalytic activation and subcellular localization of PLK-1. However, while PLK-1 inhibitors block tumor growth, they have been shown to cause severe adverse complications, such as toxicity, neutropenia, and bone marrow suppression during clinical trials, due to a lack of selectivity and specificity within the human kinome. To minimize these toxicities, inhibitors should be tested against all protein kinases in vivo and in vitro to enhance selectivity and specificity against targets. Here, we discuss the potency and selectivity of PLK-1-targeted inhibitors and their molecular interactions with PLK-1 domains.