Focal adhesion kinase (FAK) is considered intimately involved in cancer progression. Our previous research has demonstrated that overexpression of FAK is an early and frequent event in squamous cell carcinomas of the supraglottic larynx, and it is associated with the presence of metastases in cervical lymph nodes. The purpose of this study was to examine the functional role of FAK in the progression of head and neck squamous cell carcinomas (HNSCC). To this end, expression of FAK-related nonkinase (FRNK) or small interfering RNA (siRNA) against FAK was used to disrupt the FAK-induced signal transduction pathways in the HNSCC-derived SCC40 and SCC38 cell lines. Similar phenotypic effects were observed with the two methodological approaches in both cell lines. Decreased cell attachment, motility and invasion were induced by FRNK and FAK siRNA, whereas cell proliferation was not impaired. In addition, increased cell invasion was observed upon FAK overexpression in SCC cells. FRNK expression resulted in a downregulation of MMP-2 and MMP-9 expression. Interestingly, MMP-2 overexpression in FRNK-expressing cells rescued FRNK inhibition of cell invasion. This is the first demonstration of a direct rescue of impaired cell invasion by the re-expression of MMP-2 in a tumour cell type with decreased expression of functional FAK. Collectively, these data reported here support the conclusion that FAK enhances invasion of HNSCC by promoting both increased cell motility and MMP-2 production, thus providing new insights into possible therapeutic intervention strategies. Head and neck squamous cell carcinoma (HNSCC) is one of the most common types of human cancer, comprising B50% of all malignancies in some developing nations. HNSCC is associated with severe disease-and treatment-related morbidity and has a 5-year survival rate of B50%. This survival rate has remained largely unchanged in the past three decades (Sankaranarayanan et al, 1998;Gonzalez-Botas and Vazquez Barro, 2006). A major determinant of the lethal progression of HNSCC is the spreading of the malignant cells to regional lymph nodes which represents a major prognostic indicator (Forastiere et al, 2001). Thus, attempts to identify the genes involved in metastasis are pivotal for the early prediction of HNSCC behaviour and development of novel molecular therapies. However, the identities of molecular alterations that endow cancer cells with these metastatic functions are largely unknown.The process of metastasis consists of sequential and selective steps including proliferation, motility, invasion, loss of cell -cell and cell -matrix adhesion, and remodelling of the extracellular matrix. A key factor involved in the control of cellextracellular matrix interactions is focal adhesion kinase (FAK), an intracellular tyrosine kinase protein that is localised to cellular focal contact sites (Schaller et al, 1992). Initially, phosphorylation of FAK occurs on its major autophosphorylation site, Tyr 397 . Phosphorylation of this tyrosine initiates a cascade of signal transdu...

Cortactin () and the focal adhesion kinase () are two major candidate genes to, respectively, drive 11q13- and 8q24-associated aggressive behavior in various cancers. Recent evidence uncovered their clinical relevance in early stages of tumorigenesis as promising biomarkers for cancer risk assessment. Using a multicenter validation study, CTTN and FAK expression was evaluated by immunohistochemistry (IHC) in a cohort of 109 patients with laryngeal precancerous lesions, and correlated with clinicopathologic parameters and laryngeal cancer risk. The pathophysiologic role of CTTN and FAK was further investigated using functional studies in cellular models. Positive CTTN and FAK expression (scores 2 and 3) was detected in 49 (41%) and 35 (32%) laryngeal dysplasias, respectively. Univariate Cox analysis showed that CTTN and FAK expression but not histologic grading was significantly associated with both recurrence risk and laryngeal cancer risk. Patients carrying strong CTTN- or FAK-expressing lesions (score 3) experienced the highest laryngeal cancer incidence (log-rank < 0.001). In multivariate stepwise analysis, FAK expression [HR = 13.91; 95% CI, 4.82-40.15; < 0.001] and alcohol consumption (HR = 2.22; 95% confidence interval, 1.17-4.20; = 0.014) were significant independent predictors of laryngeal cancer development. Targeting FAK by either RNAi or pharmacologic inhibitors effectively blocked cell growth, colony formation, and invasion into 3D collagen matrices. CTTN and FAK emerge as powerful predictors of laryngeal cancer risk and recurrence risk beyond histologic grading. Our work supports the applicability of IHC CTTN and FAK as complementary markers for risk stratification in patients with laryngeal precancerous lesions. .

Tumor growth and progression is the result of a complex process controlled not only by malignant cancer cells but also by the surrounding tumor microenvironment (TME). Cancer associated fibroblasts (CAFs), the most abundant cellular component of TME, play an active role in tumor invasion and metastasis by promoting cancer cell invasion through cell-cell interactions and secretion of pro-invasive factors such as extracellular matrix (ECM)-degrading proteases. Due to their tumor-promoting activities, there is an emerging interest in investigating CAFs biology and its potential as drug targets for cancer therapies. Here we describe an easy and highly reproducible quantitative method to analyze CAF invasive activity by forming multicellular spheroids embedded into a three-dimensional (3D) matrix that mimics in vivo ECM. Subsequently, invasion is monitored over time using a time-lapse microscope. We also provide an automated image analysis system that enables the rapid quantification of the spheroid area increase (invasive area) over time. The use of a 96-well plate format with one CAF spheroid per well and the automated analysis provides a method suitable for drug screening test, such as protease inhibitors.