In Vivo Invasion of Head and Neck Squamous Cell Carcinoma Cells Does Not Require Macrophages

Abstract

Invasion of tumor cells into the local stroma is an important component in cancer progression.Here we report studies of the in vivo invasion of head and neck squamous cell carcinoma (HNSCC) cells in response to applied gradients of a growth factor [epidermal growth factor (EGF)] and a chemokine (CXCL12), using orthotopic floor-of-mouth models. Analysis of the invading cells indicated that >75% of them were tumor cells, about 15% macrophages, and <10% were unidentified. Surprisingly, although macrophages invaded together with tumor cells, macrophage contributions were not required for HNSCC invasion. CXCL12-induced in vivo invasion of HNSCC cells was also observed and found to occur via a unidirectional transactivation of epidermal growth factor receptor (EGFR) through CXCR4. Inhibition of tumor necrosis factor-␣-converting enzyme using TNF-␣ protease inhibitor-2 selectively inhibited CXCL12-induced invasion but not EGF-induced invasion, consistent with CXCL12 activation of EGFR via release of EGFR ligands. Head and neck squamous cell carcinoma (HNSCC) is one of the 10 most common types of cancer in the world, with over 500,000 new cases per year and 250,000 deaths worldwide as estimated by the World Health Organization. This includes 48,000 new cases and 11,260 deaths in 2009 from HNSCC in the United States. 1 HNSCC originates from mucosal tissues of the upper aerodigestive tract and spans the oral cavity to the larynx. Despite some improvements in treatment methods, the 5-year survival rate remains just above 50%. 1 Current treatments for HNSCC include single and multimodality therapies using surgical and nonsurgical approaches (chemotherapy and/or radiotherapy). 2 A key constraint that limits the ability of surgical treatment to cure HNSCC is the location-adequate margins to guarantee removal of all tumor cells are difficult to achieve in many cases without severely compromising quality of life or survival. Thus, the degree to which tumor cells have locally spread from the primary tumor can impact the likelihood of recurrence. Indeed, morphological examination of HNSCC has revealed that the pattern of tumor invasion, presence of perineural invasion, and presence of inflammatory cells correlate with clinical outcome. [3][4][5][6] Understanding the mechanisms underlying HNSCC invasion could provide an opportunity to reduce local invasion and improve patient outcome. The epidermal growth factor receptor (EGFR) is often overexpressed in HNSCC 7,8 and correlated with poor prognosis. 9 In addition to driving proliferation, the EGFR has the potential to drive invasion. EGFR ligands are chemoattractants, stimulating directly cell motility and HNSCC invasion in vitro. 10 -12 Studies of EGFR function in HNSCC in vivo have focused on tumor growth, 13,14 and direct evaluation of EGFR-mediated invasion in vivo has been poorly explored.

Prognostic significance of the tumour-adjacent tissue in head and neck cancers

“…In conjunction with the fact that EGF was expressed less in T than in A, existence of grow supporting mechanisms of tumour cells by tumour-adjacent tissues can be assumed. It was also found that EGF gradients could direct invasion into surrounding tissues [57]. Van Limbergen et al observed that FLT1 increased expression in the tumour tissue as compared with the normal epithelium [54], but we found no significant differences between FLT1 expression in tumour, tumour-adjacent tissues or tonsillectomies.…”

Targeting the Epidermal Growth Factor Receptor: Exploring the Potential of Novel Inhibitor N-(3-Ethynylphenyl)-6, 7-bis (2-methoxyethoxy) Quinolin- 4-Amine Using Docking and Molecular Dynamics Simulation

“…Crystal structure of the EGFR protein (PDB id: 1M17) was retrieved from PDB databank (http://www.pdb.org/) [3,9,11]. The optimization of protein as well as inhibitors was carried out using UCSF Chimera software, implying amber parameters, followed by minimization with MMTK method in 500 steps with a step size of 0.02 Å (www.cgl.ucsf.edu/ chimera/) [9].…”

“…Epidermal growth factor receptor (EGFR) is a cell-surface receptor tyrosine kinase (RTK) belonging to the epidermal growth factor family (EGF-family). It is unidirectionally transactivated through CXCR4 in HNSCC cells [3]. EGFR driven signalling pathway in HNSCC is predominantly responsible for the malignant features of the disease.…”

Grundlagen der Tumorentstehung und die Bedeutung Humaner Papillomaviren (HPV) bei Kopf-Hals-Karzinomen

“…Morphologische Studien an HNSCC konnten zeigen, dass das Muster der Invasion, eine perineurale Invasion und die Prä-sens von Entzündungszellen mit dem klinischen Verlauf korrelieren [ 85 ] . Bei HNSCC liegt häufi g EGFR (epidermal growth factor receptor) verstärkt exprimiert vor.…”

“…Neben dem stimulierenden Einfl uss von EGFR auf die Proliferation von Zellen verfügt EGFR auch über die Fähigkeit die Invasion von Tumorzellen zu fördern, indem die zelluläre Mobilität verstärkt wird. Dies konnte in vitro bereits für HNSCC-Zellen gezeigt werden [ 86 ] und in einer kürzlich erschienenen Studie konnte im Tiermodell in vivo bestätigt werden, dass der Ligand von EGFR (EGF) und das Chemokin CXCL12 die Invasion bei HNSCC induziert [ 85 ] . Im weiteren Verlauf des Wachstums wird ab einer bestimmten Größe des Tumors sowohl für die Sauerstoff versorgung, als auch für die Entsorgung von Abfallprodukten des Stoff wechsels eine eigene Blutversorgung erforderlich.…”