pki-166 and Head-and-Neck-Neoplasms

Improved understanding of tumor biology has led to the identification of numerous growth factors that are involved in malignant transformation and tumor progression. Many of these factors induce cellular responses through receptors with intrinsic tyrosine kinase (TK) activity. Therefore, inhibiting receptor TK activity is a way to effectively block the tumorigenic effects that arise from these pathways. The HER family of TK receptors is overexpressed or dysregulated in many types of human cancer. As a result these receptors were identified as targets for cancer therapy. Several agents have been developed that reversibly, or irreversibly, inhibit one, two or all of the HER receptors. Tarceva and Iressa are HER1-TK inhibitors that are advanced in development. Clinical data show that these agents as monotherapy have antitumor activity in patients with various types of solid tumor and are well tolerated; encouraging data are also produced when Tarceva or Iressa are combined with chemotherapeutic agents. Other dual or pan-HER, reversible or irreversible, TK inhibitors are being investigated in phase I trials. Early data show that they are generally well tolerated and have provided evidence of antitumor activity. HER-TK inhibitors are exciting agents that are likely to have a substantial impact on the way we treat patients with cancer.

Topics: Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Enzyme Inhibitors; ErbB Receptors; Erlotinib Hydrochloride; Female; Gefitinib; Head and Neck Neoplasms; Humans; Lung Neoplasms; Morpholines; Ovarian Neoplasms; Protein-Tyrosine Kinases; Pyrimidines; Pyrroles; Quinazolines; Receptor, ErbB-2

Because survival for patients with oral cancer has not improved over the past 25 years, new approaches for treatment are needed. Targeted molecular therapy against epidermal growth factor receptor (EGFR) has shown promise as an adjuvant therapy in preliminary studies in several solid tumors, including head and neck cancer. The objective of this study was to determine the efficacy of paclitaxel and PKI166, a novel inhibitor of EGFR, against oral cavity cancer.. JMAR human oral cancer cells were pretreated for 1 h with PKI166 and then stimulated with epidermal growth factor. EGFR-specific tyrosine kinase autophosphorylation measured by Western immunoblotting was inhibited by PKI166 in a dose-dependent fashion at all doses tested (0.01-1 micro M). Next, the induction of apoptosis in JMAR cells treated with paclitaxel (0.001 to 0.1 micro M) with or without PKI166 (0, 1, or 2 micro M) was determined using a propidium iodide assay. The addition of 2.0 micro M PKI166 significantly increased tumor cell death, shifting the amount of paclitaxel needed to induce apoptosis in 50% of cells from 0.1 to 0.001 micro M. These in vitro findings were confirmed using an orthotopic model of oral cancer. JMAR oral cancer cells were implanted into the tongues of nude mice. After lingual tumors developed, mice were randomized into four groups (n = 10): (a) oral PKI166 (100 mg/kg); (b) i.p. paclitaxel (200 micro g/wk); (c) PKI166 and paclitaxel; or (d) placebo. Mice treated with PKI166/paclitaxel demonstrated a significant increase in survival (P = 0.028). After necropsy, all tongue tumors were evaluated for apoptosis by the terminal deoxynucleotidyl transferase-mediated nick end labeling assay. A greater apoptotic fraction of tumor cells was found in tumors of mice treated with paclitaxel and PKI166 as compared with the other treatment groups (136.4 versus 37.8; P = 0.016).. Combination therapy with paclitaxel and PKI166 prolongs survival in an orthotopic preclinical model of tongue cancer by increasing programmed cell death of oral cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Blotting, Western; Cell Death; Cell Line, Tumor; Dose-Response Relationship, Drug; ErbB Receptors; Head and Neck Neoplasms; Humans; In Situ Nick-End Labeling; Ligands; Male; Mice; Mice, Nude; Microscopy, Fluorescence; Mouth Neoplasms; Neoplasms; Paclitaxel; Phosphorylation; Propidium; Pyrimidines; Pyrroles; Tongue; Tongue Neoplasms; Tyrosine