ZIA SC 009179 (ZIA) | |||
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Title | The Role of TIMPs in Cell Growth, Tumor Progression and Metastasis | ||
Institution | NCI, Bethesda, MD | ||
Principal Investigator | Stetler-Stevenson, William | NCI Program Director | N/A |
Cancer Activity | N/A | Division | CCR |
Funded Amount | $457,446 | Project Dates | 00/00/0000 - 00/00/0000 |
Fiscal Year | 2016 | Project Type | Intramural |
Research Topics w/ Percent Relevance | Cancer Types w/ Percent Relevance | ||
Cancer (100.0%) Metastasis (10.0%) |
Brain (25.0%) Breast (25.0%) Lung (50.0%) Nervous System (25.0%) |
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Research Type | |||
Cancer Progression & Metastasis Systemic Therapies - Discovery and Development |
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Abstract | |||
Major Activities/Specific Objectives. The principal goal of our ongoing research effort is to develop an in depth mechanistic understanding of the MMP-independent activities of members of the TIMP family, in particular TIMP-2. We have identified the following specific objectives to obtain our goals: 1) examine the role of TIMPs in altering the growth and invasive potential of cancer stem cells (CSCs) in vitro; 2) study to effects of TIMPs on primary and metastatic tumor growth in vivo; 3) study the influence of TIMPs on recruitment of immune-modulatory cells (myeloid-derived suppressor cells (MDSC)) to the primary tumor and metastatic niche. A major focus in my lab has been to demonstrate the contribution of the MMP-independent anti-angiogenic effects to the anti-tumor activity of TIMP-2 in vivo observed by a number of investigators. To this end we employed retroviral vectors to force expression of TIMP-2 and Ala+TIMP-2 in the human non-small cell lung carcinoma (NSCLC) line A549 and then used these cell lines in tumor xenograft experiments in both nu/nu and NOD-SCID mice. Although these cell lines showed no discernable difference in basal growth rates in vitro there was significant suppression of tumor growth in both TIMP-2 (>90 %) and Ala+TIMP-2 (>75%) xenografts compared to empty vector controls as late as 40 days post tumor-inoculation. The suppression of tumor growth was accompanied by a statistically significant decrease in tumor microvascular density count (CD 31+ or CD34+), a measure of antiangiogenic effects, as well as by increased tumor cell apoptosis (also possibly due to inhibition of angiogenesis). Somewhat unexpectedly, we also observed a decrease in focal adhesion kinase (FAK) in TIMP-2 expressing tumors and a significant decrease in FAK phosphorylation (Y397) in both TIMP-2 and Ala+TIMP-2 expressing tumor cells. Our observation that both FAK and/or AKT (Protein Kinase B, PKB) phosphorylation is reduced in TIMP-2 and Ala+TIMP-2 tumor tissues is significant in that: 1) FAK is upstream of AKT signaling, and both are involved in regulation of cell migration; 2) TIMP-2 and Ala+TIMP-2 expression reduced tumor cell migration in vitro. We previously reported decreased FAK phosphorylation in endothelial cells where it is involved in control of eNOS activity. In summary, these experiments using retrovirally transduced tumor cells expressing wild type (wt) TIMP-2 or metalloprotease inhibitor-deficient Ala+TIMP-2 clearly demonstrate that the MMP-independent activities of TIMP-2, including the anti-angiogenic activity, are of sufficient magnitude to significantly impact tumor growth in vivo. Our observation of the effects of TIMP-2 and Ala+TIMP-2 on A549 tumor xenografts, led us to perform transcriptional profiling of these cell lines and tumor tissues. The observed changes in gene expression are predominantly related to decreased tumor development and reduced metastasis In contrast to control A549 cells, cells expressing TIMP-2 or Ala+TIMP-2 showed increased expression of E-cadherin, and were resistant to redistribution of cell membrane associated E-cadherin and beta-catenin following epidermal growth factor (EGF) stimulation, suggestive of a mesenchymal-epithelial transition. Other genes of interest that were differentially regulated include EGF-containing fibulin-like extracellular matrix protein 1 (EGFEMP1, fibulin 3) that was up regulated in cells expressing TIMP-2 or Ala+TIMP-2. This protein is a favorable prognostic factor in glioblastoma, and suppresses angiogenesis, cell proliferation and VEGF-A expression. However, these findings need to be confirmed and the mechanisms of the effects on downstream gene regulation remain to be identified. Key outcomes and achievements. Additional data from our gene expression profiling also revealed changes in ATP-binding cassette (ABC) transporter gene expression in NSCLC A549. This has led to a new avenue of investigation directed at understanding the effects of TIMP-2 on cancer |