1. Therapeutic Implications and Prognostic Significance of c-Met in Esophageal Squamous Cell Cancer Ching Tzao 1, Chun-Ya Wang 1, Ban-Hen Chen 1, Guang-Huan Sun 2 Division of Thoracic Surgery 1, Department of Surgery Taipei Medical University Hospital, Taipei Medical University Department of Surgery 2, Tri-Service General Hospital Taipei, Taiwan

2. No Disclosures

3. Introduction c-Met: a sub-family of RTKs with high-affinity to its ligand hepatocyte growth factor (HGF). (Naldini et al, 1991) Important in regulation of cell migration, invasion, cell proliferation and angiogenesis. (Sonnenberg et al, 1993) Activated by overexpression and constitutive kinase activation by HGF, gene amplification and its mutation (Christensen et al, 2005) Involved in carcinogenesis and tumor progression and a potential target for cancer therapy, most studied in lung, colon and breast cancers. (Ma et al., 2007)

4. Aims To determine prognostic significance of c- Met in esophageal squamous cancer (ESCC). To investigate if c-Met exerts anticancer effects in ESCC cells in vitro and in vivo.

5. Materials and Methods Immunohistochemistry for c-Met expression in 97 resected ESCC tumor samples KYSE-170 & KYSE-510 ESCC cell lines Drugs: c-Met inhibitors (SU11274 and PHA665752) Cell viability by cytotoxicity (MTT) assay Cell cycle analysis by FACS Cell migration assay Immunoblotting & immunofluorescence staining Tumor xenograft in response to c-Met inhibitor

6. Results

8. Cytotoxicity (MTT) assay by c-Met inhibitors

9. c-Met inhibitors Induced Cell Cycle Arrest in ESCC Cells Control 24hr48hr KYSE-510 G1: 67.9 ±0.5% G2: 15.46 ±0.66% S: 7.84 ±0.54% G1: 59.9 ±0.78% G2: 22.84 ±0.93% S: 8.9 ±0.51% G1: 60.56 ±0.78% G2: 24.03 ±0.56% S: 7.84 ±0.3% KYSE-170 G1: 66.95 ±0.33% G2: 16.6 ±0.34% S: 12.28 ±0.24% G1: 73.44 ±0.33% G2: 15.94 ±0.36% S: 5.14 ±0.13% G1: 73.11 ±0.15% G2: 15.41 ±0.23% S: 5.41 ±0.16%

10. Alterations of Cell Cycle Regulatory Proteins Induced by c-Met Inhibitors

11. Intrinsic Apoptosis Induced by c-Met Inhibitors in ESCC Cells KYSE-170 ESCC cell line

12. Control-naïve HGF HGF+SU11274 2  M HGF+SU11274 4  M HGF+PHA665752 2  M HGF+PHA665752 4  M * * * * KYSE-170

13. Control-naïve HGF HGF+SU11274 2  M HGF+SU11274 4  M HGF+PHA665752 2  M HGF+PHA665752 4  M KYSE-510

14. c-Met inhibitors retarded growth of KYSE-170 tumors SU111274-treatment PHA665752-treatment

15. Conclusions c-Met expression may serve as an independent prognostic predictor for ESCC. c-Met inhibitors, SU11274 and PHA665752 exerted significant anticancer effects in ESCC cell lines in vitro and in vivo, suggesting that c-Met may serve as a potential therapeutic target for ESCC.

16. Acknowledgments Dr. Yutaka Shimada from University of Kyoto, Japan for his kind gift of KYSE ESCC cell lines A grant support from National Science Council, Taiwan, Republic of China. (NSC100-2314-B-016-033)