Focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase that plays a key role in maintaining focal adhesion function and cell survival and is implicated in cell migration, adhesion, and cell cycle control (9,13,18,20,33,44). Overexpression of FAK is a common event in numerous tumor systems, including breast, colon, and thyroid carcinomas (2,24,32,41), and occurs at early stages of tumorigenesis, before a tumor has developed the capacity for invasion and metastasis (2). Importantly, FAK has been shown to be one of the critical factors protecting cells from apoptosis, but the exact mechanism is unknown (8,9,12,19,37,43). Attenuation of FAK expression by antisense oligonucleotides led to apoptosis in tumor cells (42), and the treatment of cells with anti-FAK antibody (18, 26) or overexpression of the focal adhesion targeting (FAT) domain of FAK led to cell rounding, detachment, and apoptosis (19,21,40). We have created a model system for the attenuation of FAK function by adenoviral gene transduction of the carboxy-terminal domain of FAK (FAK-CD) and have demonstrated a loss of adhesion and apoptosis in breast cancer cells with this treatment (43). Both anchoragedependent and anchorage-independent apoptotic signaling required Fas-associated death domain protein (FADD) and caspase 8, suggesting an important role for FAK in inhibiting death receptor-related apoptosis (43). This finding provided additional evidence that a death receptor-mediated apoptotic pathway or death receptor-related death domain proteins are involved in the apoptotic process triggered by the expression of FAK-CD.The loss of adhesion and induction of apoptosis upon attenuation of FAK function by the expression of FAK-CD is similar to the phenomenon of anoikis (7-9). Intriguingly, there is evidence for the involvement of death receptor-related, death domain-containing proteins in anoikis (7, 35), whereby the silencer of death domain (SODD) and dominant-negative FADD efficiently inhibited anoikis in Madin-Darby canine kidney (MDCK) cells and in a number of untransformed epithelial cell lines. In these studies, it was also shown that cell matrix detachment activated caspase 8. However, the linkage of the signaling pathways to the death receptors remains unknown.RIP is a serine/threonine kinase that contains a death domain (17, 38) and is named for its association with the death receptor complex. RIP interacts with the death domains of cell surface receptors of the tumor necrosis factor (TNF) superfamily and death domain adaptor proteins (3,5,17) and plays an indispensable role in 39). Recently, it was shown that TNF alpha-mediated activation of NF-B depends on the association of RIP and FAK (11). TNF-induced NF-B DNA binding activity and activation of IB kinases were markedly impaired in FAK Ϫ/Ϫ cells (11). However, it has been well established that RIP has a dual function and is capable of either inducing apoptosis or activating cellular survival signals (14,17,23,27,38,39). Similarly, it has been proposed that RIP is one of the switch...

N-MYC is a transcription factor important for the control of cellular differentiation and proliferation (1, 2). It is normally expressed in the brain and peripheral nervous system (1). N-MYC has been shown to influence the differentiation of neural crest cells. Early in mouse embryogenesis, N-MYC is present primarily in the migrating neural crest cells, but as the embryo matures, the expression of N-MYC becomes limited to those cells that are undergoing neuronal differentiation (3). Abnormal expression of N-MYC is most notably associated with the pediatric tumor of neural crest origin, neuroblastoma. Amplification of the N-MYC oncogene is the primary adverse prognostic indicator in human neuroblastoma (4, 5). The level of N-MYC expression has been shown to correlate with the growth (6 -9) and invasiveness (10) of neuroblastoma cells, and transgenic mice with N-MYC overexpression develop spontaneous neuroblastoma tumors (11). In addition, down-regulation of N-MYC with antisense oligonucleotides leads to decreases in both cellular proliferation and in anchorageindependent growth in the neuroblastoma cells (6, 9). Despite this information, the exact function and transcriptional gene targets of N-MYC in neuroblastoma are currently not well characterized (5).Focal adhesion kinase (FAK) 3 is a nonreceptor cytoplasmic 125-kDa protein-tyrosine kinase. Initial studies revealed that both the transcription of FAK mRNA (12) and the expression of FAK protein (13-19) are significantly increased in primary and metastatic breast, colon, and thyroid tumors compared with normal tissues and that these changes occur early in tumorigenesis. Real time PCR analysis of colorectal carcinoma and liver metastasis with matched normal colonic tissues demonstrated increased FAK mRNA abundance in the tumors and metastatic tissues compared with control tissues (20), suggesting that the increased FAK expression in human tumors occurs at the level of transcription. Recently the FAK promoter was cloned and characterized, and transcriptional regulation of the FAK promoter has been demonstrated (21).FAK controls a number of cell signaling pathways including proliferation, viability, motility, and survival (22-25). The inhibition of FAK with antisense oligonucleotides has been shown to cause decreased growth in tumor cells (26). In addition, FAK inhibition with a dominant-negative FAK protein (FAK-CD) inhibited cell growth in human melanoma cells (12) and in * The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Pancreatic cancer is a lethal disease accounting for the fourth leading cause of cancer death in USA. Focal adhesion kinase (FAK) and the insulin-like growth factor-I receptor (IGF-1R) are tyrosine kinases that activate common pathways, leading to increased proliferation and cell survival. Sparse information is available regarding their contribution to the malignant behavior of pancreatic cancer. We analyzed the relationship between FAK and IGF-1R in human pancreatic cancer cells, determined which downstream signaling pathways are altered following kinase inhibition or downregulation and studied whether dual kinase inhibition represents a potential novel treatment strategy in this deadly disease. Using immunoprecipitation and confocal microscopy, we show for the first time that FAK and IGF-1R physically interact in pancreatic cancer cells and that inhibition of tyrosine phosphorylation of either kinase disrupts their interaction. Decreasing phosphorylation of either FAK or IGF-1R alone resulted in little inhibition of cell viability or increased apoptosis. However, dual inhibition of FAK, using either a dominant-negative construct (FAK-CD) or small interfering RNA, and IGF-1R, using a specific small molecule tyrosine kinase inhibitor (AEW-541) or stable expression of a truncated, mutated IGF-1R, led to a synergistic decrease in cell proliferation and phosphorylation of extracellular signal-regulated kinase (ERK) and increase in cell detachment and apoptosis compared with inhibition of either pathway alone. Dual kinase inhibition with FAK-CD and AEW-541 resulted in a marked increase in apoptosis when FAK was displaced from the focal adhesions. Inhibition of both tyrosine kinase activities via a novel single small molecular inhibitor (TAE 226), at low doses specific for FAK and IGF-1R, resulted in significant inhibition of cell viability, decrease in phosphorylation of ERK and Akt and increase in apoptosis accompanied by cleavage of Poly (ADP-ribose) polymerase (PARP) and activation of caspase-3 in pancreatic cancer cells. Thus, simultaneous inhibition of both tyrosine kinases represents a potential novel therapeutic approach in human pancreatic adenocarcinoma.

FAK is a tyrosine kinase that functions as a key orchestrator of signals leading to invasion and metastasis. Since FAK interacts directly with a number of critical proteins involved in survival signaling in tumor cells, we hypothesized that targeting a key protein-protein interface with druglike small molecules was a feasible strategy for inhibiting tumor growth. In this study, we targeted the protein-protein interface between FAK and VEGFR-3 and identified compound C4 (chloropyramine hydrochloride) as a drug capable of 1) inhibiting the biochemical function of VEGFR-3 and FAK, 2) inhibiting proliferation of a diverse set of cancer cell types in vitro, and 3) reducing tumor growth in vivo. Chloropyramine hydrochloride reduced tumor growth as a single agent, while concomitant administration with doxorubicin had a pronounced synergistic effect. Our data demonstrate that the FAK-VEGFR-3 interaction can be targeted by small drug-like molecules and this interaction can provide the basis for highly-specific novel cancer therapeutics.

Focal adhesion kinase (FAK) is emerging as a promising cancer target because it is highly expressed at both the transcriptional and translational level in cancer and is involved in many aspects of tumor growth, invasion, and metastasis. Existing FAK-based therapeutics focus on inhibiting the kinase's catalytic function and not the large scaffold it creates that includes many oncogenic receptor tyrosine kinases and tumor suppressor proteins. Targeting the FAK scaffold is a feasible and promising approach for developing highly specific therapeutics that disrupt FAK signaling pathways in cancer.