Clinical, signaling pathway, and cellular effects of epidermal growth factor receptor (EGFR) inhibition with gefitinib in combination with paclitaxel and radiation in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN)

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Background: EGFR, overexpressed in >90% of SCCHN, activates pathways that modulate proliferation, apoptosis, and therapeutic resistance. We examined the clinical, signaling, and cellular effects of EGFR inhibition in serial tumor biopsies in patients (Pts.) with locally advanced SCCHN receiving the EGFR-inhibitor gefitinib (GEF) in combination with paclitaxel (PTX) and radiation (XRT). Methods: Phase I dose-escalation study of concurrent GEF 250 mg with weekly PTX 45mg/m2 x 6 doses and XRT to 72Gy. Eligiblity: SCCHN, Stage III-IVB, age ≥18 yr., no prior XRT or chemotherapy, ECOG ≤2, adequate organ function and informed consent. Endpoints include determination of maximum tolerated dose (MTD) and immunostaining of tumor pre- and post-treatment for expression of phospho-EGFR, Akt, Erk1/2, STAT3, NF-κB p65, Ki67, and TUNEL, and measurement of serum IL-6, IL-8, VEGF, HGF and GROα to assess the functional effects of EGFR-inhibition. Results: Four Pts., median age 63 yr. (range 41–83), 3 men, 1 woman were treated. Aspiration pneumonia and interstitial pneumonitis were each observed in 1 Pt and prolonged Grade 3/4 mucositis in all 4 Pts. Three Pts achieved a CR, with one Pt requiring neck dissection to remove a residual node. One Pt had a local CR but rapidly developed pulmonary metastasis. One Pt. exhibited decreased staining of all signaling phosphoproteins and Ki67 with increased TUNEL staining. Decrease or increase in IL-8, VEGF and HGF at one month corresponded with response or progression in two patients. Conclusions: Pulmonary complications and prolonged mucositis were dose-limiting. EGFR inhibition affects downstream signaling, cell survival and serum factors in a subset of patients.

No significant financial relationships to disclose.

Inhibition of integrin mediated cell adhesion of human head and neck squamous cell carcinoma to extracellular matrix laminin by monoclonal antibodies

We recently reported that three members of the integrin family of cell adhesion molecules, designated alpha 2 beta 1, alpha 3 beta 1, and alpha 6 beta 4, are expressed at increased levels within the tumors and cell lines of patients with SCC. These three integrins have been reported to serve as receptors for laminin isoforms, and we also previously observed that laminins are secreted by SCC cell lines isolated from patients. In this study, the expression and localization of the three integrins and laminin in situ was evaluated in ten tumor specimens from patients with SCC by immunohistochemistry using integrin subunit-specific monoclonal antibodies. The ability of the antibodies to inhibit laminin attachment of a human squamous cell carcinoma line was determined by in vitro cell adhesion assay. Laminin and the three integrins were co-localized along the invasive border of the tumor parenchyma in 10/10 patient tumor specimens. Attachment of the UM-SCC-38 cell line to laminin was strongly inhibited by specific mAbs to alpha 2 and alpha 6 integrin subunits alone, or completely using a combination of alpha 2, alpha 3, and alpha 6 subunit specific mAbs. The co-localization of the three abnormally expressed integrins and laminin in patient tumor specimens indicates the potential for interaction of these receptors and ligand in vivo. The results of the cell adhesion assays using a patient SCC cell line that expresses the same repertoire of integrins confirms that SCC attach to laminin isoforms primarily through the alpha 2, alpha 3 and alpha 6 subunit-containing integrins. These findings provide a basis for undertaking experimental studies to obtain small molecule receptor antagonists to determine the role of these integrins in tumor formation, growth, invasion and metastasis in vivo.