Targeting of DNA Damage Signaling Pathway Induced Senescence and Reduced Migration of Cancer cells.

Abstract

The heat shock 70 family protein, mortalin, has pancytoplasmic distribution pattern in normal and perinuclear in cancer human cells. Cancer cells when induced to senesce by either chemicals or stress showed shift in mortalin staining pattern from perinuclear to pancytoplasmic type. Using such shift in mortalin staining as a reporter, we screened human shRNA library and identified nine senescence-inducing siRNA candidates. An independent Comparative Genomic Hybridization analysis of 35 breast cancer cell lines revealed that five (NBS1, BRCA1, TIN2, MRE11A, and KPNA2) of the nine genes located on chromosome regions identified as the gain of locus in more than 80% cell lines. By gene-specific PCR, these five genes were found to be frequently amplified in cancer cell lines. Bioinformatics revealed that the identified targets were connected to MRN (MRE11-RAD50-NBS1) complex, the DNA damage-sensing complex. We demonstrate that the identified shRNAs triggered DNA damage response and induced the expression of tumor suppressor protein p16(INK4A) causing growth arrest of cancer cells. Furthermore, cells showed decreased migration, mediated by decrease in matrix metalloproteases. Taken together, we demonstrate that the MRN complex is a potential target of cancer cell proliferation and migration, and staining pattern of mortalin could serve as an assay to identify senescence-inducing/anticancer reagents.

• Authors: Ran Gao, Rumani Singh, Zeenia Kaul, Sunil C Kaul, Renu Wadhwa
• Journal: The journals of gerontology. Series A, Biological sciences and medical sciences (J Gerontol A Biol Sci Med Sci) Vol. 70 Issue 6 Pg. 701-13 (Jun 2015) ISSN: 1758-535X [Electronic] United States
• PMID: 24747666 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author 2014. Published by Oxford University Press on behalf of the Gerontological Society of America. All rights reserved. For permissions, please email: [email protected].

Chemical References

• Cell Cycle Proteins
• Cyclin-Dependent Kinase Inhibitor p16
• DNA-Binding Proteins
• HSP70 Heat-Shock Proteins
• KPNA2 protein, human
• MRE11 protein, human
• NBN protein, human
• Nuclear Proteins
• RNA, Double-Stranded
• TINF2 protein, human
• Telomere-Binding Proteins
• alpha Karyopherins
• BRAP protein, human
• Ubiquitin-Protein Ligases
• MRE11 Homologue Protein

Topics

• Cell Cycle Proteins
• Cell Line, Tumor
• Cell Movement
• Cellular Senescence
• Cyclin-Dependent Kinase Inhibitor p16 (metabolism)
• DNA Damage
• DNA-Binding Proteins (genetics)
• Gene Library
• HSP70 Heat-Shock Proteins (metabolism)
• Humans
• MRE11 Homologue Protein
• Neoplasms (genetics, pathology)
• Nuclear Proteins
• RNA, Double-Stranded
• Telomere-Binding Proteins
• Ubiquitin-Protein Ligases
• alpha Karyopherins