TIMP-1 Inhibits Apoptosis in Lung Adenocarcinoma Cells via Interaction with Bcl-2

Abstract

Tissue inhibitors of metalloproteinases (TIMPs) are multifaceted molecules that exhibit properties beyond their classical proteinase inhibitory function. Although TIMP-1 is a known inhibitor of apoptosis in mammalian cells, the mechanisms by which it exerts its effects are not well-established. Our earlier studies using H2009 lung adenocarcinoma cells, implanted in the CNS, showed that TIMP-1 overexpressing H2009 cells (HB-1), resulted in more aggressive tumor kinetics and increased vasculature. The present study was undertaken to elucidate the role of TIMP-1 in the context of apoptosis, using the same lung cancer cell lines. Overexpressing TIMP-1 in a lung adenocarcinoma cell line H2009 resulted in an approximately 3-fold increased expression of Bcl-2, with a marked reduction in apoptosis upon staurosporine treatment. This was an MMP-independent function as a clone expressing TIMP-1 mutant T2G, lacking MMP inhibition activity, inhibited apoptosis as strongly as TIMP1 overexpressing clones, as determined by inhibition of PARP cleavage. Immunoprecipitation of Bcl-2 from cell lysates also co-immunoprecipitated TIMP-1, indicative of an interaction between these two proteins. This interaction was specific for TIMP-1 as TIMP-2 was not present in the Bcl-2 pull-down. Additionally, we show a co-dependency of TIMP-1 and Bcl-2 RNA and protein levels, such that abrogating Bcl-2 causes a downregulation of TIMP-1 but not TIMP-2. Finally, we demonstrate that TIMP-1 dependent inhibition of apoptosis occurs through p90RSK, with phosphorylation of the pro-apoptotic protein BAD at serine 112, ultimately reducing Bax levels and increasing mitochondrial permeability. Together, these studies define TIMP-1 as an important cancer biomarker and demonstrate the potential TIMP-1 as a crucial therapeutic target.

Differential proteomics analysis of low- and high-grade of astrocytoma using iTRAQ quantification

“…The possibility of the upregulation of TIMP1 in GBM is caused by some kind of feedback mechanism to antagonize the increase of MMPs in GBM. Other than metalloproteinase inhibition function, Nalluri et al 33 and Rojiani et al 34 provided evidence that the elevated TIMP messenger RNA levels are also associated with poor clinical outcome in patients with aggressive malignant lung adenocarcinoma. Functional analysis showed that overexpressed TIMP-1 promotes tumor development through alterations in angiogenesis, increased tumorigenicity, and invasive behavior.…”

Deregulated Mucosal Immune Surveillance through Gut-Associated Regulatory T Cells and PD-1+ T Cells in Human Colorectal Cancer

“…Furthermore, we observed that genes such as TIMP1, IL-8, REG family genes (REG1A, REG1B, REG3A), HSPA6, and PHDLA1 that are associated with cell proliferation or antiapoptosis were overrepresented in colorectal adenocarcinoma cells compared with normal colon cells (Fig. 6B) (36)(37)(38)(39).…”

TIMP1 is a prognostic marker for the progression and metastasis of colon cancer through FAK-PI3K/AKT and MAPK pathway

“…Studies have shown that this protein may inhibit the proteolytic activity of matrix metalloproteinases (MMPs) by forming noncovalent 1:1 stoichiometric complexes and regulate the balance of matrix remodeling during degradation of extracellular matrix [ 5 ]. In addition to its inhibitory effect on most of the known MMPs, which are thought to be crucial for the tumor invasion and development of metastatic disease [ 6 ], TIMPs also play an important role in the regulation of cell proliferation and anti-apoptotic function [ 7 – 9 ]. Studies in vitro have demonstrated that overexpression of TIMP1 can lead to a substantially increase of genes involved in proliferation, apoptosis and signal transduction [ 5 ].…”