Recurrent/metastatic head and neck cancer remains a devastating disease with insufficient treatment options. We investigated the MET receptor tyrosine kinase as a novel target for the treatment of head and neck squamous cell carcinoma (HNSCC). MET/phosphorylated MET and HGF expression was analyzed in 121 tissues (HNSCC/normal) by immunohistochemistry, and in 20 HNSCC cell lines by immunoblotting.

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Purpose Fyn is a member of the Src family of kinases that we have previously shown to be overexpressed in prostate cancer. This study defines the biological impact of Fyn inhibition in cancer using a PC3 prostate cancer model. Experimental Design Fyn expression was suppressed in PC3 cells using an shRNA against Fyn (PC3/FYN-). Knockdown cells were characterized using standard growth curves and time-lapse video microscopy of wound assays and Dunn Chamber assays. Tissue microarray analysis was used to verify the physiologic relevance of the HGF/MET axis in human samples. Flank injections of nude mice were performed to assess in vivo growth characteristics. Results HGF was found to be sufficient to drive Fyn mediated events. Compared to control transductants (PC3/Ctrl), PC3/FYN- showed a 21% decrease in growth at 4 days (P=0.05). PC3/FYN- cells were 34% longer than control cells (P=0.018) with 50% increase in overall surface area (P<0.001). Furthermore, when placed in a gradient of HGF, PC3/FYN- cells showed impaired directed chemotaxis down an HGF gradient in comparison to PC3/Ctrl (P=0.001) despite a 41% increase in cellular movement speed. In vivo studies showed 66% difference of PC3/FYN- cell growth at 8 weeks using bidimensional measurements (P=0.002). Conclusions Fyn plays an important role in prostate cancer biology by facilitating cellular growth and by regulating directed chemotaxis- a key component of metastasis. This finding bears particular translational importance when studying the effect of Fyn inhibition in human subjects.

Esophageal cancer incidence is increasing and has few treatment options. In studying receptor tyrosine kinases associated with esophageal cancers, we have identified EPHB4 to be robustly overexpressed in cell lines and primary tumor tissues. In total, 94 squamous cell carcinoma, 82 adenocarcinoma, 25 dysplasia, 13 Barrett esophagus, and 25 adjacent or unrelated normal esophageal tissues were evaluated by immunohistochemistry. EPHB4 expression was significantly higher in all the different histologic categories than in adjacent normal tissues. In 13 esophageal cancer cell lines, 3 of the 9 SCC cell lines and 2 of the 4 adenocarcinomas expressed very high levels of EPHB4. An increased gene copy number ranging from 4 to 20 copies was identified in a subset of the overexpressing patient samples and cell lines. We have developed a novel 4-nitroquinoline 1-oxide (4-NQO)-induced mouse model of esophageal cancer that recapitulates the EPHB4 expression in humans. A specific small-molecule inhibitor of EPHB4 decreased cell viability in a timeand dose-dependent manner in 3 of the 4 cell lines tested. The small-molecule inhibitor and an EPHB4 siRNA also decreased cell migration (12%-40% closure in treated vs. 60%-80% in untreated), with decreased phosphorylation of various tyrosyl-containing proteins, EphB4, and its downstream target p125FAK. Finally, in a xenograft tumor model, an EPHB4 inhibitor abrogated tumor growth by approximately 60% compared with untreated control. EphB4 is robustly expressed and potentially serves as a novel biomarker for targeted therapy in esophageal cancers. Cancer Res; 73(1); 184-94. Ó2012 AACR.

Gene copy number analysis for some of the important molecules in lung tumorogenesis such as MET, hepatocyte growth factor (HGF, ligand for MET), epidermal growth factor receptor (EGFR) and paxillin (PXN) is likely to determine both the type of treatment and prognosis. Formalin-fixed paraffin-embedded (FFPE) archival tumor tissue samples are an excellent source for determining key molecular changes in the OncoGenome, however existing extraction procedures yield relatively poor quality genomic DNA fragments. Although FISH is the method of choice for determining amplification of a gene, a more rapid qPCR technique to determine gene copy number can be used when reasonably good quality genomic DNA is available. We report here a relatively rapid method based on microwave/chelex-100 treatment that gives rise to genomic DNA fragments ranging from 1 to 12 Kb and beyond, thereby attesting to its superior quality. Genomic PCR for β-globin gene gave reliable and reproducible results. The number of steps for extracting the DNA was kept to a minimum, and instead of precipitating the DNA, we preserved the genomic DNA extracts so as to prevent a loss in DNA yield. We found the extracts to be stable and amenable to qPCR and mutational analysis. Using lung adenocarcinoma FFPE samples and cell lines derived from lung adenocarcinomas, we demonstrated that the gene copy number for MET in lung adenocarcinoma tissue samples was preferentially increased over EGFR, HGF and PXN and that it positively correlated with better prognosis. In contrast, the genomic DNA extracted from twenty five NSCLC cell lines gave relatively higher gene copy number for all the four genes evaluated. Our results indicate that the microwave/chelex-100 based method yields good quality genomic DNA extracts that can be used for complex DNA analysis such as determination of gene copy number. In addition, our data demonstrated that the adenocarcinoma cell lines potentially evolved under ex vivo conditions, and therefore in genetic studies it is imperative to use primary tumors for generalized conclusions about lung tumors.

Small cell lung cancer (SCLC) is a devastating disease, and current therapies have not greatly improved the 5-year survival rates. Topoisomerase (Top) inhibition is a treatment modality for SCLC; however, the response is short lived. Consequently, our research has focused on improving SCLC therapeutics through the identification of novel targets. Previously, we identified MNNG HOS transforming gene (MET) to be overexpressed and functional in SCLC. Herein, we investigated the therapeutic potential of combinatorial targeting of MET using SU11274 and Top1 using 7-ethyl-10-hydroxycamptothecin (SN-38). MET and TOP1 gene copy numbers and protein expression were determined in 29 patients with limited (n = 11) and extensive (n = 18) disease. MET gene copy number was significantly increased (>6 copies) in extensive disease compared with limited disease (P = 0.015). Similar TOP1 gene copy numbers were detected in limited and extensive disease. Immunohistochemical staining revealed a significantly higher Top1 nuclear expression in extensive (0.93) versus limited (0.15) disease (P = 0.04). Interestingly, a significant positive correlation was detected between MET gene copy number and Top1 nuclear expression (r = 0.5). In vitro stimulation of H82 cells revealed hepatocyte growth factor (HGF)–induced nuclear colocalization of p-MET and Top1. Furthermore, activation of the HGF/MET axis enhanced Top1 activity, which was abrogated by SU11274. Combination of SN-38 with SU11274 dramatically decreased SCLC growth as compared with either drug alone. Collectively, these findings suggest that the combinatorial inhibition of MET and Top1 is a potentially efficacious treatment strategy for SCLC.

Background:Treatment of non-small cell lung cancer (NSCLC) remains a difficult task in oncology. Targeted inhibition of oncogenic proteins is promising. In this study, we evaluate the expression of MET and PKCß and in vitro effects of their inhibition using SU11274 and enzastaurin (LY317615.HCl) respectively.Materials and Methods:Patient samples were analyzed by immunohistochemistry for expression of PKCß and MET, utilizing tissue microarrays under an IRB-approved protocol. Expression of PKCß and MET was evaluated in cell lines by immunoblotting. Treatment with SU1174 against MET and enzastaurin against PKCß was performed in H1993 and H358 cell lines, and cell proliferation and downstream signaling (phosphorylation of MET, AKT, FAK, and GSK3ß) were evaluated by immunoblotting. Statistical analysis was performed using SPSS 16.0.Results:Expression of MET positively correlated with lymph node metastases (p=.0004), whereas PKCß showed no correlation (p=0.204). MET and PKCß expression were also strongly correlated (p<0.001). Expression of MET was observed in 5/8 cell lines (H358, H1703, A549, H1993, H2170; absent from H522, H661, or SW1573), whereas PKCß expression was observed in 8/8 cell lines. Cell proliferation was significantly impaired by treatment with SU11274 and enzastaurin, and their effects were synergistic in combination (CI=0.32 and 0.09). Phosphorylation of MET, FAK, AKT, and GSK3ß were strongly inhibited with both agents in combination.Conclusions:Concomitant inhibition of MET and PKCß significantly increased cytotoxicity in vitro against NSCLC, disrupting important downstream signaling pathways. Further evaluation in animal models is warranted.

EphB4 is a member of the largest family of receptor tyrosine kinases (RTKs), classically associated with neural development and vascular patterning in embryonic life. The cellular responses to Eph receptor stimulation by their ephrin ligands are important in mediating a wide range of biological activities, including angiogenesis, cell segregation, cell attachment, shape, and motility. EphB4 has been showed to play an oncogenic role in a number of tumors, and we report the first investigation into its role in esophageal cancer, a disease whose survival has not improved and would benefit from the identification of new targets in its treatment. We have addressed this need by exploring the Eph/ephrin receptor tyrosine kinase pathway. We utilized tissues archived at the University of Chicago as well as commercially purchased TMAs to evaluate the expression of EphB4 by IHC. Approximately 93 squamous cell carcinoma, 100 adenocarcinoma and 25 adjacent normal control samples were utilized. In addition, four adenocarcinoma and nine squamous cell carcinma cell lines were used for in vitro studies. Statistical analysis of IHC data showed a consistently higher expression of EphB4 in both squamous and adenocarcinoma compared to adjacent normal tissue. A statistically significant correlation was established between EphB4 expression and higher grades of squamous cell carcinoma, suggesting that overexpression of EphB4 in squamous cell carcinoma is directly linked to clinically aggressive tumors. The EphB4 gene was found amplified in 8/16 squamous cell carcinoma (30% with a gene copy number ≥ 3, 30% with &gt;8 copies and 10% with a copy number of 20. Of the adenocarcinomas, 3/7 samples were amplified (43% with a gene copy number of ≥4, and 14% &gt;8 copies). Three of 9 squamous cell carcinoma cell lines had a gene copy number ≥4 and rest of them had no significant variation. Only one of four adenocarcinoma cell lines had an increased gene copy number. In vitro experiments with EphB4 specific siRNA inhibited the motility and proliferation of cultured cells and the inhibition of EphB4 specifically abrogated the phosphorylation of functional proteins associated with cell motility and proliferation, especially that of phospho-FAK and phospo-AKT, the expression of which were abrogated completely by the inhibition of EphB4. Our data imply that EphB4 plays a crucial role in esophageal cancer and should be further evaluated as a therapeutic target in this disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1625. doi:10.1158/1538-7445.AM2011-1625