Comparative Proteomic Analysis of Paclitaxel Sensitive A2780 Epithelial Ovarian Cancer Cell Line and Its Resistant Counterpart A2780TC1 by 2D-DIGE: The Role of ERp57

Abstract

Epithelial ovarian cancer is the leading cause of gynecological cancer mortality. Despite good response to surgery and initial chemotherapy, chemoresistance occurrence represents a major obstacle to a successful therapy. To better understand biological mechanisms at the basis of paclitaxel resistance, a comparative proteomic approach based on DIGE coupled with mass spectrometry (MALDI-TOF and LC-MS/MS) was applied to the human epithelial ovarian cancer cell lines A2780 and its paclitaxel resistant counterpart A2780TC1. Most of the differentially expressed proteins between the two cell lines belong to the class of stress response (29%), metabolism (21%), and cell cycle and apoptosis (17%). We focused on proteins which were most strongly modulated by paclitaxel resistance and in particular on the disulphide isomerase ERp57, which may represent a chemoresistance biomarker. ERp57 was found to interact with class III beta-tubulin (TUBB3), involved in paclitaxel resistance in ovarian and other cancers. Moreover, we demonstrated a novel localization of this protein in cytoskeleton and described that ERp57/TUBB3 interaction occurs also in the nuclear compartment and in association with a multimeric complex formed by nucleolin, nucleophosmin, hnRNPK, and mortalin. Our data suggest that ERp57 plays an important role in chemoresistance mechanisms in ovarian cancer by modulating the attachment of microtubules to chromosomes following paclitaxel treatment through its interaction with TUBB3.

A Transcriptome-proteome Integrated Network Identifies Endoplasmic Reticulum thiol oxidoreductase (ERp57) as a Hub that Mediates Bone Metastasis

“…In that complex, ERp57 might exert a redox control on TUBB3 folding and the correct association of microtubules and the kinetochore (56). Further studies have evaluated the importance of this phenotype in paclitaxel resistance in ovarian cancer (57,58).…”

Characterisation of a multimeric protein complex associated with ERp57 within the nucleus in paclitaxel-sensitive and -resistant epithelial ovarian cancer cells: The involvement of specific conformational states of β-actin

“…These proteins were grouped into main functional classes. Most of the proteins were related to the category of stress response and chaperones suggesting that alterations of those processes might be involved in paclitaxel resistance (3,4). Recent studies identified ERp57, a chaperone belonging to the disulphide isomerase family involved in the correct folding of proteins, as a plausible therapeutic target in ovarian cancer.…”

Downregulation of ER60 Protease Inhibits Cellular Proliferation by Inducing G1/S Arrest in Breast Cancer Cells In Vitro

“…Some investigators have attributed this observation to ER60 protease being a key component for antigen presentation by MHC-I molecules during immune surveillance (Garbi et al, 2007;Chapman and Williams, 2010), and therefore a lower expression would facilitate immune evasion by cancer cells (Seliger et al, 2001;Dunn et al, 2006;Seliger et al, 2010). ER60 protein has also been associated with resistance to the chemotherapeutic drug Paclitaxel in A2780 ovarian cancer cells in vitro (Cicchillitti et al, 2009). However, overexpression of ER60 protease in Chinese Hamster Ovary stable transfectants has been reported to increase mitomycin C-induced DNA crosslinking leading to enhanced cytotoxicity on exposure to this anticancer drug (Celli and Jaiswal, 2003).…”

“…ER60 has been studied extensively as an endoplasmic reticulum luminal chaperone protein involved in the quality control of newly synthesized glycoproteins (Khanal and Nemere, 2007b) as well as in the assembly of major histocompatibility complex class-I (MHC-I) molecules (Vigneron et al, 2009;Chapman and Williams, 2010). Studies involving various types of tissues have shown differential expression of ER60 protease in normal tissues as compared with cancerous tissues such as breast, lung, gastric, and ovarian carcinomas (Celli and Jaiswal, 2003;Leys et al, 2007;Cicchillitti et al, 2009). However, much remains to be elucidated to fully understand the role of ER60 protease in cancer.…”