epothilone-a and Stomach-Neoplasms

The highest rates of gastric cancer occur in Eastern Asia. Fluoropyrimidine-based therapy is used initially in unresectable and metastatic disease, but no single standard of care exists following disease progression. Ixabepilone, an epothilone B analog, is a non-taxane microtubule-stabilizing agent with clinical activity across multiple tumor types approved by the United States Food and Drug Administration for treatment of metastatic breast cancer.. Asian patients with unresectable or metastatic gastric adenocarcinoma who had failed fluoropyrimidine-based chemotherapy received ixabepilone 40 mg/m(2) by 3-h intravenous infusion every 3 weeks. The primary endpoint was objective response rate (ORR).. Fifty-two patients were treated (65.4 % men; median age: 56.5 years). The ORR was 15.4 % (95 % confidence interval [CI] 6.9-28.1); 8 patients achieved partial responses for a median duration of 3.1 months (95 % CI 2.6-4.1 months) and 26 patients (50.0 %) had stable disease. Median progression-free survival was 2.8 months (95 % CI 2.1-3.5 months). The most common grade 3 non-hematological toxicities were fatigue (9.6 %), decreased appetite (7.7 %), sensory neuropathy (5.8 %), and diarrhea (5.8 %). Grade 3/4 neutropenia occurred in 46.2 % of patients.. Ixabepilone is active in Asian patients with advanced gastric cancer and shows a toxicity profile similar to those previously reported in other tumor types.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Epothilones; Female; Fluorouracil; Humans; Male; Middle Aged; Stomach Neoplasms; Tubulin Modulators

Ixabepilone is one of the epothilones, a new class of cytotoxics, that function as microtubule-stabilizing agents. With the primary endpoint of assessing ixabepilone's response rate against metastatic gastric cancer previously treated with a taxane, we performed a multi-center phase II trial.. Patients with histologically documented metastatic gastric or gastroesophageal adenocarcinoma, who had previously received a taxane, were eligible. Patients were required to have near normal organ function, > or =18 years of age, ECOG performance status of 0 or 1. A written informed consent was obtained from all patients. Ixabepilone was administered over one hour intravenously at a dose of 50 mg/m2 every 21 days (23 patients; cohort A) and 24 subsequent patients were treated with an amended protocol schedule to receive 6 mg/m2 intravenously on days 1-5 every 21 days (cohort B).. A total of 47 patients were treated. Most patients were men with a median performance status of 1. Two of 23 patients in cohort A achieved a confirmed partial response (9%, 95% CI 1.1-28%) but none of the 24 patients in cohort B achieved a response. A higher proportion of patients in cohort A experienced Grade 3/4 toxicities compared with those in cohort B.. Ixabepilone, on a once every 21-day schedule, is modestly active against metastatic gastric cancer previously treated with a taxane. The days 1-5 every 21 days schedule had a more favorable safety profile but no activity. The results of this study suggest that once every 21-day ixabepilone schedule should be pursued further in untreated gastric or gastroesophageal adenocarcinoma patients.

Topics: Adenocarcinoma; Adult; Aged; Antineoplastic Agents; Bridged-Ring Compounds; Disease Progression; Epothilones; Female; Humans; Male; Middle Aged; Multicenter Studies as Topic; Peripheral Nervous System Diseases; Stomach Neoplasms; Taxoids

Gastric cancer is an important health issue worldwide. Currently, improving the therapeutic efficacy of chemotherapy drugs is an important goal of cancer research. Alpha-7 nicotine acetylcholine receptor (A7-nAChR) is the key molecule that mediates gastric cancer progression, metastasis, and therapy responses; however, the role of A7-nAChR in the therapeutic efficacy of ixabepilone remains unclear. A7-nAChR expression was silenced by small interfering RNA (siRNA) technology. The cytotoxicity of ixabepilone was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and ixabepilone-induced apoptosis was analyzed by flow cytometry and annexin V/propidium iodide (PI) apoptotic assay. The expression patterns of anti-apoptotic proteins (AKT, phospho-AKT, Mcl-1, and Bcl-2) and pro-apoptotic proteins (Bad and Bax) were determined by western blot. Our study found that A7-nAChR knockdown (A7-nAChR-KD) AGS cells were more sensitive to ixabepilone administration than scrambled control AGS cells. We found that A7-nAChR knockdown enhanced ixabepilone-induced cell death as evidenced by the increased number of annexin V-positive (apoptotic) cells. After scrambled control and A7-nAChR-KD cells were treated with ixabepilone, we found that pAKT and AKT levels were significantly reduced in both groups of cells. The levels of Bcl-2 and the anti-apoptotic Mcl-1 isoform increased dramatically after ixabepilone treatment in scrambled control cells but not in A7-nAChR-KD cells. Bad and Bax levels did not change between the treatment group and vehicle group in both A7-nAChR-KD and scrambled control cells, whereas cleaved PARP levels dramatically increased in ixabepilone-treated A7-nAChR-KD cells. Our results demonstrated that knockdown of A7-nAChR enhanced the sensitivity of gastric cancer cells to ixabepilone administration. Thus, the A7-nAChR expression level in patients with gastric cancer may be a good indicator of ixabepilone sensitivity.

Topics: Adenocarcinoma; alpha7 Nicotinic Acetylcholine Receptor; Apoptosis; Blotting, Western; Cell Cycle; Cell Proliferation; Drug Resistance, Neoplasm; Epothilones; Flow Cytometry; Humans; RNA, Small Interfering; Stomach Neoplasms; Tubulin Modulators; Tumor Cells, Cultured