imetelstat and Carcinoma--Squamous-Cell

The phase 3 MONET1 study evaluated motesanib (a small-molecule inhibitor of vascular endothelial growth factor receptors) plus carboplatin/paclitaxel versus placebo plus carboplatin/paclitaxel as first-line therapy for advanced non-small-cell lung cancer (NSCLC). Treatment and enrollment of patients with squamous histology were permanently discontinued following higher early mortality and gross hemoptysis in those with squamous NSCLC who received motesanib. Enrollment of patients with nonsquamous histology was temporarily halted, but resumed following a protocol amendment (Scagliotti et al. J Clin Oncol. 2012;30:2829-2836). Herein, we report data from the squamous cohort.. Patients with stage IIIB/IV or recurrent squamous NSCLC (without prior systemic therapy for advanced disease) received up to six 3-week cycles of chemotherapy (carboplatin, area under the curve 6 mg/mL•min/paclitaxel, 200 mg/m) and were randomized 1:1 to receive motesanib 125 mg (Arm A) or placebo (Arm B) once daily. The primary end point was overall survival.. Three-hundred and sixty patients with squamous NSCLC were randomized (Arm A, n = 182; Arm B, n = 178) between July 2007 and November 2008. Twenty-three patients (13%) in Arm A and 10 (6%) in Arm B had fatal adverse events within the first 60 days of treatment. Among these, six patients in Arm A, but none in Arm B, had fatal bleeding events. At final analysis, serious adverse events had occurred in 47% of patients in Arm A and 29% of patients in Arm B. Median overall survival was similar in Arms A and B (11.1 versus 10.7 months).. Motesanib plus carboplatin/paclitaxel had unacceptable toxicity compared with carboplatin/paclitaxel alone in patients with advanced squamous NSCLC.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Disease-Free Survival; Double-Blind Method; Early Termination of Clinical Trials; Female; Hemoptysis; Humans; Indoles; Lung Neoplasms; Male; Middle Aged; Niacinamide; Oligonucleotides; Paclitaxel; Survival Rate

The morbidity and mortality of esophageal cancer is one of the highest around the world and the principal therapeutic method is radiation. Thus, searching for sensitizers with lower toxicity and higher efficiency to improve the efficacy of radiation therapy is critical essential. Our research group has previously reported that imetelstat, the thio-phosphoramidate oligonucleotide inhibitor of telomerase, can decrease cell proliferation and colony formation ability as well as increase DNA breaks induced by radiation in esophageal cancer cells. Further study in this project showed that imetelstat significantly sensitized esophageal cancer cells to radiation in vitro. Later study showed that imetelstat leads to increased cell apoptosis. We also measured the expression level of several DNA repair and apoptosis signaling proteins. pS345 CHK1, γ-H2AX, p53 and caspase3 expression were up-regulated in imetelstat treated cells, identifying these factors as molecular markers. Mouse in vivo model using imetelstat at clinically achievable concentrations and fractionated irradiation scheme yielded results demonstrating radiosensitization effect. Finally, TUNEL assay, caspase 3 and Ki67 staining in tumor tissue proved that imetelstat sensitized esophageal cancer to radiation in vivo through promoting cell apoptosis and inhibiting cell proliferation. Our study supported imetelstat increase radiation sensitivity of esophageal squamous cell carcinoma through inducing cell apoptosis and the specific inhibitor of telomerase might serve as a potential novel therapeutic tool for esophageal squamous cell carcinoma therapy.

Topics: Animals; Apoptosis; Carcinoma, Squamous Cell; Esophageal Neoplasms; Esophageal Squamous Cell Carcinoma; Humans; Indoles; Male; Mice; Mice, Nude; Niacinamide; Oligonucleotides; Random Allocation; Telomerase; Xenograft Model Antitumor Assays

Telomerase is mainly active in human tumor cells, which provides an opportunity for a therapeutic window on telomerase targeting. We sought to evaluate the potential of the thio-phosphoramidate oligonucleotide inhibitor of telomerase, imetelstat, as a drug candidate for treatment of esophageal cancer. Our results showed that imetelstat inhibited telomerase activity in a dose-dependent manner in esophageal cancer cells. After only 1 week of imetelstat treatment, a reduction of colony formation ability of esophageal cancer cells was observed. Furthermore, long-term treatment with imetelstat decreased cell growth of esophageal cancer cells with different kinetics regarding telomere lengths. Short-term imetelstat treatment also increased γ-H2AX and 53BP1 foci staining in the esophageal cancer cell lines indicating a possible induction of DNA double strand breaks (DSBs). We also found that pre-treatment with imetelstat led to increased number and size of 53BP1 foci after ionizing radiation. The increase of 53BP1 foci number was especially pronounced during the first 1h of repair whereas the increase of foci size was prominent later on. This study supports the potential of imetelstat as a therapeutic agent for the treatment of esophageal cancer.

Topics: Carcinoma, Squamous Cell; Cell Proliferation; DNA Breaks, Double-Stranded; DNA Repair; DNA, Neoplasm; Esophageal Neoplasms; Fluorescent Antibody Technique; Humans; Indoles; Niacinamide; Oligonucleotides; Radiation, Ionizing; Real-Time Polymerase Chain Reaction; Telomerase; Telomere; Tumor Cells, Cultured

The growth of solid tumors is dependent on the continued stimulation of endothelial cell proliferation and migration resulting in angiogenesis. The angiogenic process is controlled by a variety of factors of which the vascular endothelial growth factor (VEGF) pathway and its receptors play a pivotal role. Small-molecule inhibitors of VEGF receptors (VEGFR) have been shown to inhibit angiogenesis and tumor growth in preclinical models and in clinical trials. A novel nicotinamide, AMG 706, was identified as a potent, orally bioavailable inhibitor of the VEGFR1/Flt1, VEGFR2/kinase domain receptor/Flk-1, VEGFR3/Flt4, platelet-derived growth factor receptor, and Kit receptors in preclinical models. AMG 706 inhibited human endothelial cell proliferation induced by VEGF, but not by basic fibroblast growth factor in vitro, as well as vascular permeability induced by VEGF in mice. Oral administration of AMG 706 potently inhibited VEGF-induced angiogenesis in the rat corneal model and induced regression of established A431 xenografts. AMG 706 was well tolerated and had no significant effects on body weight or on the general health of the animals. Histologic analysis of tumor xenografts from AMG 706-treated animals revealed an increase in endothelial apoptosis and a reduction in blood vessel area that preceded an increase in tumor cell apoptosis. In summary, AMG 706 is an orally bioavailable, well-tolerated multikinase inhibitor that is presently under clinical investigation for the treatment of human malignancies.

Topics: Angiogenesis Inhibitors; Animals; Carcinoma, Squamous Cell; Cell Line; Cell Line, Tumor; Endothelium, Vascular; Female; Fibroblasts; Humans; Indoles; Leukemia, Megakaryoblastic, Acute; Mice; Mice, Nude; Niacinamide; Oligonucleotides; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-kit; Rats; Rats, Sprague-Dawley; Receptors, Vascular Endothelial Growth Factor; Skin; Transplantation, Heterologous; Umbilical Veins