In mammalian cells, PLK-1 is primarily localized in the centrosome, where it is responsible for centrosome separation and maturation. PLK-1-specific antibodies introduced into HeLa cells by microinjection prevent centrosome separation and reduce γ-tubulin accumulation, suggesting that PLK-1 functions

selleck in regulating centrosome function [8]. PLK-1 is also a target of the G2 DNA damage checkpoint, where it undergoes ubiquitin-dependent proteolysis mediated by the checkpoint protein Chfr, implicating the loss of Plk-1 function as an important response to DNA damage during the G2 phase of the cell cycle [9]. Correspondingly, the elevation of PLK-1 expression occurs in a broad range of human tumors [10, 11], and a close correlation has been documented between mammalian PLK-1 expression and progression of endometrial and ovarian cancers [12, 13]. Therefore, PLK-1 is implicated as a critical candidate target for understanding find more the progression of cervical carcinoma and improving chemotherapy. However, little is known about the importance of PLK-1 in the development and management of cervical carcinoma. To address this issue, we investigated the expression and distribution of PLK-1 in cervical carcinoma tissues. Furthermore, in order to determine the importance of PLK-1 in tumor progression, we investigated the effects of PLK-1 knockdown on the biological characteristics of HeLa

cells by taking advantage of small interference RNA (siRNA) against PLK-1. Our results elucidate the pathogenesis of cervical carcinoma and may help to develop a novel strategy to improve the efficiency of chemotherapy delivered to patients with cervical carcinoma. Materials and methods Immunohistochemical staining

For immunohistochemical staining, thirty-six surgically resected human cervical carcinoma tissue samples were collected from the Department BCKDHB of Obstetrics and Gynecology, Wuhan Union Hospital. The study was approved by the institutional review boards. Immunohistochemical staining was performed according to our previous protocol [14]. Briefly, human tumor tissues were embedded in paraffin and cut into 5-μm sections that were placed onto glass slides. After antigen retrieval, sections were stained for the expression of PLK-1 (BD Biosciences, San Diego, CA) (1:100)detected by streptavidin-biotin-horseradish peroxidase complex formation. Tumor sections stained for IgG instead of primary antibodies were used as the negative control. The immunoactivities of PLK-1 were ranked according to the percentage of positive tumor cells: score 3 (> 75%), score 2 (25-75%), score 1 (< 25%), and score 0 (negative). Cell culture, transient transfection, RNA interference, and cisplatin treatment HeLa cells were cultured in RPMI 1640 supplemented with 10% fetal calf serum (FCS) (Invitrogen, Carlsbad, CA,). Plasmid construction and transfection were performed as previously described [4]. Briefly, PLK-1 cDNA was cloned into the pcDNA3.