TIMP-1 Inhibits apoptosis in lung adenocarcinoma cells via interaction with Bcl-2

Srilatha Nalluri, Sampa Ghoshal-Gupta, Ammar Kutiyanawalla, Sitaram Gayatri, Byung Rho Lee, Shahanawaz Jiwani, Amyn M. Rojiani, Mumtaz V. Rojiani

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19 Scopus citations

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.

Original languageEnglish (US)
Article numbere0137673
JournalPloS one
Volume10
Issue number9
DOIs
StatePublished - Sep 14 2015

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ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

Cite this

Nalluri, S., Ghoshal-Gupta, S., Kutiyanawalla, A., Gayatri, S., Lee, B. R., Jiwani, S., Rojiani, A. M., & Rojiani, M. V. (2015). TIMP-1 Inhibits apoptosis in lung adenocarcinoma cells via interaction with Bcl-2. PloS one, 10(9), [e0137673]. https://doi.org/10.1371/journal.pone.0137673