Tumor suppressor p53 plays a crucial role in tumor suppression. Recently, we identified leukemia inhibitory factor (LIF) as a novel p53 target gene. To date, the role of LIF in tumorigenesis is poorly understood. Our following preliminary data strongly suggest that LIF is a novel negative regulator of p53 and plays an important role in colorectal cancer. 1) LIF is overexpressed in a high percentage of human colorectal cancers that we examined. 2) LIF down-regulates p53 protein levels and function in colorectal cancer cells, including HCT116 p53+/+ cells. 3) LIF promotes the proliferation of colorectal cancer cells, and the growth and angiogenesis of xenograft colorectal tumors. We hypothesize that LIF overexpression plays an important role in promoting tumorigenesis and therapeutic resistance in colorectal cancers, and the down-regulation of p53 function is an important underlying mechanism. In this proposed study, 1) we will investigate the down- regulation of p53 levels and function by LIF in colorectal cells in addition to HCT116 p53+/+ cells. 2) We will determine the mechanisms by which LIF down-regulates p53. Our preliminary studies strongly suggest that LIF down-regulates p53 function through the induction of specific p53 negative regulators in colorectal cells. To test this hypothesis, we will investigate whether endogenous LIF protein regulates the expression of these p53 negative regulators in colorectal cells. Furthermore, we will investigate the role and mechanisms of these p53 negative regulators in mediating the down-regulation of p53 by LIF in colorectal cells. 3) We will determine the role of LIF in promoting the growth, angiogenesis and therapeutic resistance in xenograft colorectal tumors. Furthermore, we will test the hypothesis that the down-regulation of p53 by LIF is an important mechanism for the promoting effect of LIF on tumorigenesis in xenograft colorectal tumors. 4) We will further investigate the mechanism accounting for LIF overexpression in both colorectal cancer cells and human colorectal cancer samples. The goal of this proposed study is to understand the role and molecular mechanisms of LIF in colorectal cancer. This study should greatly increase our understanding of molecular mechanisms of colorectal tumorigenesis;and furthermore, have the direct potential to develop LIF as an important tumor biomarker and a therapeutic target for colorectal cancers.

Public Health Relevance

The goal of this proposed study is to understand the role and molecular mechanism of LIF in colorectal cancers. It is our anticipation that this study will establish the important role of LIF overexpression in promoting tumorigenesis and therapeutic resistance in colorectal cancers, and provide the down- regulation of p53 by LIF as an important underlying mechanism. This study will have the direct potential to develop LIF as an important tumor biomarker and a therapeutic target for colorectal cancers.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
7R01CA160558-02
Application #
8474719
Study Section
Cancer Molecular Pathobiology Study Section (CAMP)
Program Officer
Watson, Joanna M
Project Start
2012-09-01
Project End
2017-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
2
Fiscal Year
2013
Total Cost
$310,130
Indirect Cost
$115,080
Name
Rbhs -Cancer Institute of New Jersey
Department
Type
DUNS #
078728091
City
New Brunswick
State
NJ
Country
United States
Zip Code
08903
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