Overview of the Laboratory Research Efforts.The main focus of my research laboratory program is to develop novel targeted molecular therapeutics for thoracic malignancies. This program can be broadly classified into 2 categories: selective induction of apoptosis of cancer cells by activation of receptor-mediated death signaling pathways and selective inhibition of receptor-mediated growth signaling pathways including intracellular mitogen-activated protein kinases to down-modulate malignant phenotypes and tumor-induced angiogenesis of cancer cells. Six original research manuscripts have been accepted for publication in major peer-reviewed journals including Molecular Cancer Therapeutics, Apoptosis, Neoplasia and British Journal of Cancer and 2 others are under review. 1. Evaluation of the anti-angiogenesis effect of MEK inhibition in thoracic cancers. As an extension of our previous work examining the effect of blocking EGFR-dependent signal transduction using the selective EGFR-RTKI PD153035 to mediate down-regulation of expression of pro-metastasis phenotypes in cultured thoracic cancer cells, we evaluated the effect of blocking MEK-mediated signaling on disrupting tumor angiogenesis. The MEK/ERK1/2 pathway is constitutively active in a panel of more than 15 cultured thoracic cancer cells even in the absence of serum. At low micromolar concentrations UO126 selectively abrogates MEK activity. Treating cultured thoracic cancer cells with UO126 results in inhibition of cell proliferation, clonogenicity as well as reduction of cell motility and invasion of Matrigel. UO126 (1.0 to 40 microM) significantly suppressed pro-angiogenesis cytokines VEGF, IL8 and PGE2 production by thoracic cancer cells. Moreover, EGF- and IL-1 induced robust upregulation of VEGF, IL8 and PGE2 is significantly blocked by UO126 (2.5 to 10 microM). These findings suggest MEK inhibition may indirectly inhibit tumor angiogenesis via suppression of cancer-derived VEGF, IL8, PGE2 expression. Reduction of cancer cell-derived VEGF production by UO126 has function significance as conditioned media of cancer cells previously treated with UO126 does not support HUVEC (human umbilical vein endothelial cells) viability in vitro. Direct exposure of HUVEC to UO126 results in dose-dependent inhibition of cell proliferation in vitro as well as suppression of endothelial function as indicated by profound reduction of vessel sproutings the rat aortic aorta ring assay. Interestingly, UO126 does not affect proliferation and viability of primary fibroblasts in vitro. Western blots analysis indicates that UO126 significantly suppress ERK1/2 phosphorylation without affecting phosphorylation of AKT or adducin in both cancer cells and primary HUVECs. This study demonstrates the antiangiogenesis property of MEK inhibitor via its ability to interfere with both cancer cell-derived pro-angiogenesis cytokines production as well as direct inhibition of endothelial cell function. Future study is being planned to evaluate the angiangiogenesis property of MEK inhibitor in an animal in vivo model.2. Development of clinically applicable strategies to enhance the tumoricidal property of the recombinant apoptosis-inducing ligand Apo2L/TRAIL. My laboratory has focused a great deal of efforts to develop clinically applicable strategies to enhance the anticancer effect of the recombinant death-inducing protein ligand Apo2L/TRAIL (Tumor Necrosis factor-Related Apoptosis Inducing Ligand) for thoracic malignancies (primary cancers of the lung, the esophagus and the pleura). This project is part of an ongoing CRADA with Genentech, Inc. Five manuscripts pertaining to our research on Apo2L/TRAIL have been recently accepted for publication in various research journals such as Molecular cancer Therapeutics, Apoptosis, Neoplasia and The Cancer Journal and the Journal of Thoracic and Cardiovascular Surgery. My laboratory has demonstrated that the majority of cultured thoracic cancer
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