The MCT-1 oncogene product impairs cell cycle checkpoint control and transforms human mammary epithelial cells

Hsin Ling Hsu, Bo Shi, Ronald B. Gartenhaus*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Multiple copies in T-cell maligancy (MCT-1) is a putative oncogene initially identified in a human T-cell lymphoma. Forced expression of MCT-1 has recently been shown to induce cell transformation and proliferation, as well as to activate survival-related PI-3K/AKT pathways protecting cells from apoptosis. MCT-1 protein is stabilized in response to DNA damage. The impact of MCT-1 overexpression on DNA damage response remains unknown. Here, we show that MCT-1 deregulates cell cycle checkpoints. The phosphorylation of genomic stabilizers H2AX and NBS1 are enhanced in MCT-1-overexpressing cells. Forced expression of MCT-1 significantly increases the number of DNA damage-induced foci involving γ-H2AX and 53BP1. In MCT-1-overexpressing cells, the proportion of S-phase cell population is preferentially increased after exposure to γ-irradiation compared to controls. Knockdown of endogenous MCT-1 using an siRNA approach attenuates the H2AX phosphorylation and the G1/S checkpoint defect. Furthermore, MCT-1 is capable of transforming immortalized human mammary epithelial cells and promoting genomic instability. These data shed light on the role of MCT-1 in the cellular response to DNA damage and its involvement in malignant transformation.

Original languageEnglish (US)
Pages (from-to)4956-4964
Number of pages9
JournalOncogene
Volume24
Issue number31
DOIs
StatePublished - Jul 21 2005

Keywords

  • Cell cycle
  • Transformation

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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