NONO and RALY proteins are required for YB-1 oxaliplatin induced resistance in colon adenocarcinoma cell lines

Tsofack, Garand Chantal, Sereduk Chris, Chow Donald, Aziz Meraj, Guay David, Yin, Le Bel, Lebel Michel

Description

YB-1 is a multifunctional protein that affects transcription, splicing, and translation. Overexpression of YB-1 in breast cancers causes cisplatin resistance. Recent data have shown that YB-1 is also overexpress in colorectal cancer. In this study, we tested the hypothesis that YB-1 also confers oxaliplatin resistance in colorectal adenocarcinomas. Results We show for the first time that transfection of YB-1 cDNA confers oxaliplatin resistance in two colorectal cancer cell lines (SW480 and HT29 cell lines). Furthermore, we identified by mass spectrometry analyses important YB-1 interactors required for such oxaliplatin resistance in these colorectal cancer cell lines. A tagged YB-1 construct was used to identify proteins interacting directly to YB-1 in such cells. We then focused on proteins that are potentially involved in colorectal cancer progression based on the Oncomine microarray database. Genes encoding for these YB-1 interactors were also examined in the public NCBI comparative genomic hybridization database to determine whether these genes are localized to regions of chromosomes rearranged in colorectal cancer tissues. From these analyses, we obtained a list of proteins interacting with YB-1 and potentially involved in oxaliplatin resistance. Oxaliplatin dose response curves of SW480 and HT29 colorectal cancer cell lines transfected with several siRNAs corresponding to each of these YB-1 interactors were obtained to identify proteins significantly affecting oxaliplatin sensitivity upon gene silencing. Only the depletion of either NONO or RALY sensitized both colorectal cancer cell lines to oxaliplatin. Furthermore, depletion of NONO or RALY sensitized otherwise oxaliplatin resistant overexpressing YB-1 SW480 or HT29 cells. Conclusion These results suggest knocking down NONO or RALY significant counteracts oxaliplatin resistance in colorectal cancers overexpressing the YB-1 protein.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2011
• Nombre de lectures: 3
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

Tsofacket al.Molecular Cancer2011,10:145 http://www.molecularcancer.com/content/10/1/145

R E S E A R C H

Open Access

NONO and RALY proteins are required for YB1 oxaliplatin induced resistance in colon adenocarcinoma cell lines 1,2 1 3 3 3 4 3 Serges P Tsofack , Chantal Garand , Chris Sereduk , Donald Chow , Meraj Aziz , David Guay , Hongwei H Yin 1,2* and Michel Lebel

Abstract Background:YB1 is a multifunctional protein that affects transcription, splicing, and translation. Overexpression of YB1 in breast cancers causes cisplatin resistance. Recent data have shown that YB1 is also overexpress in colorectal cancer. In this study, we tested the hypothesis that YB1 also confers oxaliplatin resistance in colorectal adenocarcinomas. Results:We show for the first time that transfection of YB1 cDNA confers oxaliplatin resistance in two colorectal cancer cell lines (SW480 and HT29 cell lines). Furthermore, we identified by mass spectrometry analyses important YB1 interactors required for such oxaliplatin resistance in these colorectal cancer cell lines. A tagged YB1 construct was used to identify proteins interacting directly to YB1 in such cells. We then focused on proteins that are potentially involved in colorectal cancer progression based on the Oncomine microarray database. Genes encoding for these YB1 interactors were also examined in the public NCBI comparative genomic hybridization database to determine whether these genes are localized to regions of chromosomes rearranged in colorectal cancer tissues. From these analyses, we obtained a list of proteins interacting with YB1 and potentially involved in oxaliplatin resistance. Oxaliplatin dose response curves of SW480 and HT29 colorectal cancer cell lines transfected with several siRNAs corresponding to each of these YB1 interactors were obtained to identify proteins significantly affecting oxaliplatin sensitivity upon gene silencing. Only the depletion of either NONO or RALY sensitized both colorectal cancer cell lines to oxaliplatin. Furthermore, depletion of NONO or RALY sensitized otherwise oxaliplatin resistant overexpressing YB1 SW480 or HT29 cells. Conclusion:These results suggest knocking down NONO or RALY significant counteracts oxaliplatin resistance in colorectal cancers overexpressing the YB1 protein.

Background Colorectal cancer is the third leading cause of cancer related death in the Western world (National Cancer Institute; 2009). Over 50% of those diagnosed require systemic therapy at some point during the disease tra jectory. Clinical resistance is almost inevitable for advanced colorectal cancer within 612 months of any given therapy. For example, clinical responses of meta static cancers (e.g. death and elimination of cancer cells) to the most advanced therapeutic agents range from 15

* Correspondence: [e-mail] 1 Centre de Recherche en Cancérologie de l’Université Laval, Hôpital Hôtel Dieu de Québec, 9 McMahon St, Québec, G1R 2J6, Canada Full list of author information is available at the end of the article

to 40%, indicating intrinsic resistance in a majority of colorectal cancer tissues [1]. In addition, acquired resis tance almost inevitably occurs in tumors that initially responded [1]. One of the most effective regimens against colorectal cancers, either in adjuvant or in meta static settings, is the combination of fluoropirimidine and oxaliplatin. Oxaliplatin is a third generation plati num analogue that kills cells by forming adducts on DNA, the most prevalent of which is intrastrand link age of two adjacent guanines [2]. Nevertheless, the majority of patients with colon cancer are either intrin sically resistant to this drug or become resistant during therapy. Oxaliplatinresistant cells are characterized by decreased DNA adduct formation [3]. The exact

© 2011 Tsofack et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.