Inhibition of nuclear factor-κB and target genes during combined therapy with proteasome inhibitor bortezomib and reirradiation in patients with recurrent head-and-neck squamous cell carcinoma

Purpose: To examine the effects the proteasome inhibitor bortezomib (VELCADE) on transcription factor nuclear factor-kappa B (NF-kappa B) and target genes and the feasibility of combination therapy with reirradiation in patients with recurrent head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: The tolerability and response to bortezomib 0.6 mg/m(2) and 0.9 mg/m(2) given twice weekly concurrent with daily reirradiation to 50-70 Gy was explored. Blood proteasome inhibition and NF-kappa B modulated cytokines and factors were measured. Proteasome inhibition, nuclear localization of NF-kappa B phospho-p65, apoptosis, and expression of NF-kappa B-modulated mRNAs were compared in serial biopsies from accessible tumors. Results: The maximally tolerated dose was exceeded, and study was limited to 7 and 2 patients, respectively, given bortezomib 0.6 mg/m(2) and 0.9 mg/m(2)/dose with reirradiation. Grade 3 hypotension and hyponatremia were dose limiting. Mucositis was Grade 3 or less and was delayed. The mean blood proteasome inhibition at 1, 24, and 48 It after 0.6 mg/m(2) was 32%, 16%, and 7% and after 0.9 mg/m(2) was 56%, 26%, and 14%, respectively. Differences in proteasome and NF-kappa B activity, apoptosis, and expression of NF-kappa B-modulated cell cycle, apoptosis, and angiogenesis factor mRNAs were detected in 2 patients with minor tumor reductions and in serum NF-kappa B-modulated cytokines in 1 patient with a major tumor reduction. Conclusions: In combination with reirradiation, the maximally tolerated dose of bortezomib was exceeded at a dose of 0.6 mg/m(2) and the threshold of proteasome inhibition. Although this regimen with reirradiation is not feasible, bortezomib induced detectable differences in NF-kappa B localization, apoptosis, and NF-kappa B-modulated genes and cytokines in tumor and serum in association with tumor reduction, indicating that other schedules of bortezomib combined with primary radiotherapy or reirradiation may merit future investigation. (c) 2005 Elsevier Inc.