epothilone-a and Carcinoma--Non-Small-Cell-Lung

Progress in the treatment of non-small-cell lung cancer (NSCLC) will require the introduction of new agents as well as better use of existing therapies. Targeted therapies are likely to have a profound effect on the treatment of NSCLC after identification of patients who are most likely to benefit. The epothilones are novel anti-tubulin agents derived from Sorangium cellulosum. β III tubulin overexpression has been implicated as a mechanism of anti-tubulin resistance that can be overcome by epothilones. Several epothilones have advanced to clinical trials; ixabepilone (BMS247550, aza-epothilone B, Bristol-Myers Squibb, New York, NY), patupilone (EPO906, Novartis, Basel, Switzerland) and sagopilone (ZK-EPO, ZK-219477, Schering AG, Berlin-Wedding, Germany) are currently in active development. Several of the epothilones, most notably ixabepilone, have demonstrated activity in lung cancer in phase I and II trials, including taxane-resistant patients. Although a phase II study failed to show superior outcome in patients with β III tubulin overexpression, other aspects of the epothilones argue for their continued development.

Topics: Bridged-Ring Compounds; Carcinoma, Non-Small-Cell Lung; Drug Discovery; Drug Resistance, Neoplasm; Epothilones; Humans; Lung Neoplasms; Taxoids; Tubulin Modulators

Lung cancer is a leading cause of death among adults. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases. For more than half of all patients diagnosis does not occur until the disease has metastasised. At this advanced stage, the 5-year survival rate is just 15%. Platinum-based chemotherapy forms the backbone of treatment for patients with advanced NSCLC and forms an important component of the therapeutic regimen for many patients with earlier stage disease. However, although a number of agents are available to partner the platinum-based compounds, treatment selection is largely empiric, and chemoresistance is a considerable barrier to improving outcomes. The identification of biologic and other markers to guide treatment selection, thus ensuring patients receive the most effective regimen for their individual tumour and avoid exposure to toxic agents from which they are unlikely to benefit, will be critical to improve outcomes for patients with NSCLC. The development of alternative agents for those patients who express predictors of a negative clinical response is of vital importance. A variety of biomarkers are emerging, including expression of DNA repair enzymes, ribonucleotide subunits and betaIII tubulin. Treatment algorithms based on elucidation of such markers to guide treatment selection can already be envisaged. For example, those patients with high betaIII tubulin expression should be considered for epothilone therapy as an alternative to taxane-based regimens. The epothilones may be preferred option as the evidence suggests that these agents retain activity versus taxane-resistant cancers. This paper reviews the evidence base for betaIII tubulin expression as a prognostic and predictive biomarker in NSCLC and briefly explores the implications for clinical decision making of this and other emerging biomarkers.

Topics: Antineoplastic Agents; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Drug Resistance, Neoplasm; Epothilones; Humans; Lung Neoplasms; Prognosis; Taxoids; Tubulin

Antitubulin agents are among the most active drugs for the treatment of non-small-cell lung cancer. The taxanes paclitaxel and docetaxel are highly active and frequently used for adjuvant therapy after resection of localized disease and in combination with radiation for locally advanced disease and treatment of patients with advanced disease. Despite their benefits, these drugs have significant problems, including toxicity and limited efficacy. Recently, new taxane formulations and novel antitubulin agents have been developed. In some cases, these drugs have reduced toxicity with preserved efficacy. In other cases, these agents have potentially unique activity and have now advanced to late-stage trials. This review evaluates 2 novel paclitaxel formulations, albumin-bound paclitaxel and paclitaxel poliglumex. New antimicrotubulin agents, including the epothilones, colchicine-binding antivascular agents, and vinca alkaloids, are also discussed.

Topics: Antineoplastic Agents; Bibenzyls; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Drug Resistance, Neoplasm; Epothilones; Humans; Lung Neoplasms; Paclitaxel; Polyglutamic Acid; Tubulin Modulators; Vinblastine; Vinorelbine

The treatment of patients with advanced non-small cell lung cancer has changed considerably in the past decade. This paper reviews the most significant changes seen in chemotherapy and the most promising new agents in development for this disease.. Chemotherapy prolongs survival and improves quality of life in patients with a good performance status and appears to alleviate disease-related symptoms in patients with a lower performance status. Platinum-based regimens became standard; none of the third-generation drug combinations seemed to be superior to the others. Nonplatinum combinations are reasonable alternatives now and offer a better toxicity profile in certain populations. Attempts to add molecular-targeted therapy to combination chemotherapy have failed except for bevacizumab. New compounds such as pemetrexed, bortezomib, TLK286, bevacizumab, and the epothilones are currently being evaluated in non-small cell lung cancer.. Management of non-small cell lung cancer has improved considerably in the past decade. The overall benefit of chemotherapy over supportive care has been shown, platinum-based doublets have been established, nonplatinum regimens have been developed, chemotherapy has been used more broadly in subgroups of patients who have been previously neglected, and a shorter chemotherapy duration has been shown to be equally effective. After hitting a plateau in the benefit of chemotherapy, new drugs with novel action mechanisms such as the ones described here offer hope to improve therapy for this disease.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Boronic Acids; Bortezomib; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Epothilones; Glutamates; Glutathione; Guanine; Humans; Lung Neoplasms; Organoplatinum Compounds; Oxaliplatin; Paclitaxel; Pemetrexed; Pyrazines

Epothilones are cytotoxic macrolides with a similar mechanism of action to paclitaxel but with the potential advantage of activity in taxane-resistant settings in preclinical models. The epothilones ixabepilone, patupilone, BMS-310705, KOS-862 and ZK-EPO are in early clinical trials for cancer treatment. Phase I studies have shown that dose-limiting toxicities of epothilones are generally neurotoxicity and neutropoenia although initial studies with patupilone indicated that diarrhoea was dose limiting. Neuropathy induced by ixabepilone may be schedule dependent. Over 20 Phase II studies of epothilones in cancer treatment have been reported, and significant activity in taxane-sensitive tumour types (such as breast, lung and prostate cancers) has been noted. Response rates in taxane-refractory metastatic breast cancer are relatively modest, but ixabepilone and patupilone have shown promising efficacy in hormone-refractory metastatic prostate cancer and in taxane-refractory ovarian cancer.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Drug Administration Schedule; Drug Evaluation, Preclinical; Drug Resistance, Neoplasm; Epothilones; Female; Humans; Lung Neoplasms; Male; Prostatic Neoplasms; Tubulin Modulators

Cytotoxic agents have unequivocal activity in non-small cell lung cancer. Currently available agents have demonstrated the ability to prolong life and improve quality of life in advanced disease, and to increase the rate of cure when used in stage I and II disease in the adjuvant setting and as part of chemoradiotherapy in stage III disease. These agents have served as the core regimen to which agents effecting newly discovered molecular targets are added. However, there is little question that there is much room for improvement. A number of new agents have been identified that either derive from older drugs or affect their targets in novel ways. In particular, tubulin has been an attractive target since the dawn of medical oncology. A number of new antitubulin agents are currently in development. Epothilones are novel agents that bind to the same site as taxanes, yet are structurally distinct. Xyotax and abraxane are agents in which paclitaxel is delivered in a novel fashion that may both reduce toxicity and enhance activity. ABT 751 is an agent that targets the colchicine site of tubulin. Another approach is to enhance the activity of currently available agents by targeting detoxification and resistance pathways. TLK-286 is a novel agent that may enhance the activity of previously available agents by inhibiting GST-pi, a detoxifying mechanism that may be of particular relevance to platinum agents. It has also demonstrated some single-agent cytotoxic activity.

Topics: Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Cytotoxins; Drug Delivery Systems; Epothilones; Glutathione; Humans; Lung Neoplasms; Taxoids; Tubulin Modulators

The treatment of lung cancer--small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC)--is a significant challenge in oncology. The best reported median survival remains near 1 year in advanced NSCLC despite several decades of steady improvement and extensive research with traditional chemotherapy drugs and novel compounds targeted to different aspects of tumor cell growth and function (such as the epidermal growth factor receptor). Extensive-stage SCLC survival is only slightly better. Novel "targeted" therapeutic agents hold promise, but cytotoxic therapy remains the backbone of treatment. Many new cytotoxic agents are currently in development. In this review, we will focus on 2 classes of cytotoxins: epothilones and topoisomerase I inhibitors. Epothilones are microtubule stabilizers with a mechanism of action similar to that of the taxanes, with preclinical activity superior to that of the taxanes. Phase I trials have been completed for patupilone and ixabepilone, and there are encouraging phase II data with ixabepilone in NSCLC. A phase II trial of patupilone is ongoing. The camptothecins, which are topoisomerase I inhibitors, have a long history in the treatment of lung cancer, but the currently available drugs, topotecan and irinotecan, have limitations. Gimatecan and other novel camptothecins have superior preclinical activity and promising phase I/II data in NSCLC and SCLC.

Topics: Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Clinical Trials as Topic; Enzyme Inhibitors; Epothilones; Humans; Lung Neoplasms; Prognosis; Topoisomerase I Inhibitors

There are several new cytostatic agents under investigation for the treatment of advanced non-small cell lung cancer either as first or second-line. In this review we will present the current information about oxaliplatin, epothilones, irinotecan and alimta.

Topics: Antineoplastic Agents; Camptothecin; Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Epothilones; Glutamates; Guanine; Humans; Irinotecan; Lung Neoplasms; Organoplatinum Compounds; Oxaliplatin; Pemetrexed; Thymidylate Synthase

Treatment options for patients with non-small cell lung cancer (NSCLC) with brain metastases are limited. Patupilone (EPO906), a blood-brain barrier-penetrating, microtubule-targeting, cytotoxic agent, has shown clinical activity in phase 1/2 studies in patients with NSCLC. This study evaluates the efficacy, pharmacokinetics, and safety of patupilone in NSCLC brain metastases.. Adult patients with NSCLC and confirmed progressive brain metastases received patupilone intravenously at 10 mg/m(2) every 3 weeks. The primary endpoint of this multinomial 2-stage study combined early progression (EP; death or progression within 3 weeks) and progression-free survival at 9 weeks (PFS9w) to determine drug activity.. Fifty patients with a median age of 60 years (range, 33-74 years) were enrolled; the majority were men (58%), and most had received prior therapy for brain metastases (98%). The PFS9w rate was 36%, and the EP rate was 26%. Patupilone blood pharmacokinetic analyses showed mean areas under the concentration-time curve from time zero to 504 hours for cycles 1 and 3 of 1544 and 1978 ng h/mL, respectively, and a mean steady state distribution volume of 755 L/m(2) . Grade 3/4 adverse events (AEs), regardless of their relation with the study drug, included diarrhea (24%), pulmonary embolisms (8%), convulsions (4%), and peripheral neuropathy (4%). All patients discontinued the study drug: 31 (62%) for disease progression and 13 (26%) for AEs. Twenty-five of 32 deaths were due to brain metastases. The median time to progression and the overall survival were 3.2 and 8.8 months, respectively.. This is the first prospective study of chemotherapy for recurrent brain metastases from NSCLC. In this population, patupilone demonstrated activity in heavily treated patients.

Topics: Administration, Intravenous; Adult; Aged; Antineoplastic Agents; Brain Neoplasms; Carcinoma, Non-Small-Cell Lung; Disease Progression; Drug Administration Schedule; Epothilones; Female; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasm Recurrence, Local; Prospective Studies; Survival Analysis; Treatment Outcome

Sagopilone is the first fully synthetic epothilone in clinical development and has proven preclinical activity in tumor models. This multicenter, randomized, open-label, phase II study examined the efficacy and safety of three regimens with two doses and two infusion durations of second-line sagopilone in pretreated patients with stage IIIB or IV non-small-cell lung cancer.. Eligibility criteria included: at least one measurable lesion by modified response evaluation criteria in solid tumors; World Health Organization performance status of 0 or 1; and failure of previous platinum-based chemotherapy. Patients were randomized to receive: 16 mg/m2 sagopilone over 3 h (treatment arm A); 22 mg/m(2) sagopilone over 0.5 h (treatment arm B); or 22 mg/m2 sagopilone over 3h (treatment arm C). Treatment duration was two to six courses every 3 weeks; more than six treatment courses were permitted if there was sustained clinical benefit. The primary efficacy endpoint was best overall response after six courses; at least five confirmed responders per arm indicated a successful outcome.. In total, 128 patients (44, arm A; 41, arm B; 43, arm C) were randomized; 127 received at least one infusion of sagopilone. Baseline demographic data were similar across all arms. Eight patients across all arms had a confirmed partial response; the primary endpoint was not achieved. The most frequently reported adverse event (AE) was peripheral sensory neuropathy (75%). Most hematologic AEs were grade 1 or 2.. As fewer than five patients per arm responded after six treatment courses, the primary endpoint was not met. Sagopilone was only moderately tolerated. Most AEs, including peripheral neuropathy, were grade 1 or 2; hematologic toxicities were rare.

Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Benzothiazoles; Carcinoma, Non-Small-Cell Lung; Drug Administration Schedule; Drug-Related Side Effects and Adverse Reactions; Epothilones; Female; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Prospective Studies; Treatment Outcome

Retrospective studies have reported that tumor expression of the beta-3 tubulin (β3T) isoform is an unfavorable prognostic factor in non-small-cell lung cancer (NSCLC) treated with tubulin-inhibiting chemotherapy. Ixabepilone is a tubulin-inhibiting agent with low susceptibility to multiple resistance mechanisms including β3T isoform expression in several tumor models. This randomized phase II study evaluated ixabepilone-based chemotherapy in stage IIIb/IV NSCLC, compared with paclitaxel-based chemotherapy. Tumor specimens were prospectively evaluated for β3T expression.. Patients were stratified by β3T status (positive v negative) and randomly assigned at a ratio of 1:1 to receive ixabepilone (32 mg/m(2)) and carboplatin (area under concentration-time curve [AUC], 6) or paclitaxel (200 mg/m(2)) and carboplatin (AUC, 6) for up to six cycles. The primary end point was progression-free survival (PFS) in the β3T-positive subgroup.. Ninety-five patients (β3T positive, 52; β3T negative, 43) received ixabepilone plus carboplatin; 96 patients (β3T positive, 49; β3T negative, 47) received paclitaxel plus carboplatin. No significant differences in median PFS were observed between arms for either subgroup (β3T positive, 4.3 months in both arms; β3T negative, 5.8 v 5.3 months). Ixabepilone did not significantly improve overall survival (OS) for the β3T-positive subset or the overall population. Adverse events were similar between the two arms and comparable with those in previous studies.. There was no predictive value of β3T in differentiating clinical activity of ixabepilone- or paclitaxel-containing regimens. Ixabepilone did not improve PFS or OS in patients with β3T-positive tumors. β3T-positive patients had worse PFS relative to β3T-negative patients, regardless of treatment; hence, β3T expression seems to be a negative prognostic factor, but not a predictive factor, in advanced NSCLC treated with either ixabepilone or paclitaxel platinum-based doublets.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Biomarkers, Tumor; Carboplatin; Carcinoma, Non-Small-Cell Lung; Disease-Free Survival; Drug Administration Schedule; Epothilones; Female; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Paclitaxel; Predictive Value of Tests; Prospective Studies; Treatment Outcome; Tubulin; Tubulin Modulators

Sagopilone (ZK219477) is a new and fully synthetic epothilone with activity against multi-drug resistant tumour cell lines. It has demonstrated clinical activity in several solid tumours like ovarian cancer and melanoma. Data about clinical efficacy of sagopilone in small-cell lung cancer are lacking. Here we report the first phase-I trial of sagopilone in combination with cisplatin in previously untreated metastatic small-cell lung cancer patients.. Chemonaive patients with metastatic small-cell lung cancer (SCLC) received sagopilone in four different dosing schedules ranging from 12 to 22 mg/m(2) (on day 1 as 3-h infusion) followed by a fixed dose of cisplatin of 75 mg/m(2) as 1-h infusion on day 1. Chemotherapy was administered every 3 weeks to a maximum of six cycles. The primary objective was determination of dose-limiting toxicities (DLTs) and the maximum-tolerated dose (MTD) in this setting. Secondary objectives were assessment of objective response rates (ORR) as well as investigation of sagopilone pharmacokinetics.. Twenty-six patients received a total of 107 treatment cycles of the platinum-sagopilone doublet. The recommended phase-II dose (RD) and schedule was found to be 19 mg/m(2) sagopilone followed by 75 mg/m(2) cisplatin. Peripheral neuropathy turned out as dose-limiting toxicity when the combination was administered over a median of four cycles. Objective responses were observed in six out of seven SCLC patients (85.7%) treated with the RD.. Sagopilone and cisplatin can be safely combined in the first-line treatment of metastasised SCLC. This combination demonstrated preliminary efficacy and should be further evaluated within phase-II trials.

Topics: Antineoplastic Combined Chemotherapy Protocols; Benzothiazoles; Carcinoma, Non-Small-Cell Lung; Cisplatin; Epothilones; Female; Humans; Lung Neoplasms; Male; Neoplasm Metastasis; Prospective Studies

Epothilones, a new class of cytotoxic agents, have demonstrated activity in non-small-cell lung cancer (NSCLC). This phase II study examined ixabepilone/carboplatin (cohort A) and ixabepilone/carboplatin/bevacizumab (cohort B) as first-line therapy for patients with advanced NSCLC.. Patients were enrolled to either cohort A or B at physician discretion and when eligibility met. Eligible patients had newly diagnosed stage III/IV NSCLC, ECOG PS 0-1, adequate organ function, no active CNS metastases, and, in cohort B, bevacizumab treatment criteria. Both cohorts received ixabepilone 30 mg/m2 and carboplatin AUC=6 IV day 1 every 3-weeks for a maximum of 6 cycles. Patients assigned to cohort B also received bevacizumab 15 mg/kg IV day 1 of each cycle, and could continue single-agent bevacizumab for 6 additional cycles.. Eighty-two patients (median age, 63 years; majority stage IV and former smokers) were enrolled from 11/08 to 10/09 (A-42, B-40) and received medians of 4 and 6 cycles, respectively. The ORRs were 29% and 50%. After median follow up of 17.5 months (A) and 15.7 months (B), median progression free survivals were A-5.3 months (95% CI 2.8-8.6) and B-6.7 months (95% CI 5.1-8.4), with median overall survivals of 9.3 months (95% CI 6.4-16.6) 13.2 months (95% CI 8.9-upper limit not reached), respectively. Grade 3/4 toxicity included: anemia (A-10%, B-27%), neutropenia (A-31%, B-48%), thrombocytopenia (A-19%, B-20%), fatigue (A-10%, B-23%), infection (A-5%, B-20%), and hypersensitivity reaction (A-2%, B-5%). There was one treatment-related death, due to hemoptysis in a cohort B patient with squamous histology.. Ixabepilone can be safely combined with carboplatin in newly diagnosed patients with advanced NSCLC. The benefits of treatment appear consistent with those achieved with other modern platinum-doublet regimens. The addition of bevacizumab increases toxicities, however, these are largely expected and reversible. The high ORR and OS observed in the bevacizumab-cohort are encouraging, but would require validation in a larger randomized trial of cohort A versus B.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Carboplatin; Carcinoma, Non-Small-Cell Lung; Epothilones; Female; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Treatment Outcome

Ixabepilone (BMS-247550) is a semi-synthetic, microtubule stabilizing epothilone B analogue which is more potent than taxanes and has displayed activity in taxane-resistant patients. The human plasma pharmacokinetics of ixabepilone have been described. However, the excretory pathways and contribution of metabolism to ixabepilone elimination have not been determined. To investigate the elimination pathways of ixabepilone we initiated a mass balance study in cancer patients. Due to autoradiolysis, ixabepilone proved to be very unstable when labeled with conventional [14C]-levels (100 microCi in a typical human radio-tracer study). This necessitated the use of much lower levels of [14C]-labeling and an ultra-sensitive detection method, Accelerator Mass Spectrometry (AMS). Eight patients with advanced cancer (3 males, 5 females; median age 54.5 y; performance status 0-2) received an intravenous dose of 70 mg, 80 nCi of [14C]ixabepilone over 3 h. Plasma, urine and faeces were collected up to 7 days after administration and total radioactivity (TRA) was determined using AMS. Ixabepilone in plasma and urine was quantitated using a validated LC-MS/MS method. Mean recovery of ixabepilone-derived radioactivity was 77.3% of dose. Fecal excretion was 52.2% and urinary excretion was 25.1%. Only a minor part of TRA is accounted for by unchanged ixabepilone in both plasma and urine, which indicates that metabolism is a major elimination mechanism for this drug. Future studies should focus on structural elucidation of ixabepilone metabolites and characterization of their activities.

Topics: Adenocarcinoma; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Chromatography, Liquid; Colonic Neoplasms; Epothilones; Feces; Female; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasms; Ovarian Neoplasms; Pancreatic Neoplasms; Sigmoid Neoplasms; Tandem Mass Spectrometry

Ixabepilone is the first in a new class of antineoplastic agents, the epothilones and their analogs. This international, randomized, phase II trial assessed two administration schedules of ixabepilone as second-line therapy in patients with non-small-cell lung cancer (NSCLC).. Patients had experienced disease progression after one prior cisplatin- or carboplatin-based chemotherapy regimen. Ixabepilone was administered as a single 32 mg/m(2) 3-hour infusion (77 patients; arm A) or a 6 mg/m(2) 1-hour infusion daily for 5 consecutive days (69 patients; arm B) in a 3-week cycle.. The intent-to-treat objective response rate was 14.3% in arm A and 11.6% in arm B. Median duration of response was 8.7 months (95% CI, 5.3 to 9.5 months) in arm A and 9.6 months (95% CI, 6.1 to 19.7 months) in arm B. Median time to progression was 2.1 months (95% CI, 1.4 to 2.8 months) for arm A and 1.5 months (95% CI, 1.4 to 2.8 months) for arm B. Median survival was 8.3 months (95% CI, 5.8 to 11.5 months) for arm A, and 7.3 months (95% CI, 5.7 to 11.7 months) for arm B; the 1-year survival rate (both cohorts) was 38%. Responses occurred in patients with taxane-pretreated and platinum-refractory tumors. Both regimens had an acceptable toxicity profile. Myelosuppression was manageable, manifesting primarily as neutropenia and leukopenia. Neuropathy was primarily sensory, generally mild to moderate in severity, and mostly reversible (both regimens).. Single-agent ixabepilone had clinically relevant activity and an acceptable safety profile in patients with advanced NSCLC whose tumors had failed one prior platinum-based chemotherapy regimen.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Disease Progression; Epothilones; Female; Humans; Lung Neoplasms; Male; Middle Aged; Platinum Compounds; Treatment Outcome

To evaluate the effect of Ixabepilone on quiescent or hypoxic cells response to ionizing radiation.. NCI-H460 and A549, two human NSCLC cell lines, were employed in this experiment. Quiescent cells (QC) or hypoxic cells (HC) were induced as mentioned previously and untreated cells as control. A colony forming assay was applied to compare cellular radio-sensitivity with or without Ixabepilone. Flow cytometry and Western blot analysis were used to detect cell cycle distribution and apoptosis.. Along with an increased population of G1 cell (NCI-H46 P=0.001 3; A549 P=0.006), both HC and QC were exhibited radio-resistance compared to untreated cells (survival fraction: NCI-H460 P=0.003; A549 P=0.000 1). Moreover, it was found that Ixabepilone, which induced apoptosis in both IR-treated or untreated NSCLC cells, significantly enhanced cells death under hypoxia (decrease of survival fraction: NCI-H460 P=0.000 2; A549 P<0.01).. The existence of quiescent or hypoxic cells in solid tumors poses a critical therapeutic problem since they were resistant to IR. Ixabepilone, which induces apoptosis in NSCLC, showed great radio-sensitization effect on hypoxic cells. Following work will focus on whether Ixabepilone could increase hypoxic tumor cells radio-sensitivity in vivo, which could provide useful data for the application of Ixabepilone in clinical practice.

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Cycle; Cell Hypoxia; Cell Line, Tumor; Epothilones; Humans; Lung Neoplasms; Radiation Tolerance; Radiation, Ionizing

Sagopilone, an optimized fully synthetic epothilone, is a microtubule-stabilizing compound that has shown high in vitro and in vivo activity against a broad range of human tumor models. We analyzed the differential mechanism of action of sagopilone in non-small cell lung cancer cell lines in vitro. Sagopilone inhibited proliferation of non-small cell lung cancer cell lines at lower nanomolar concentration. The treatment with sagopilone caused strong disturbances of cellular cytoskeletal organization. Two concentration-dependent phenotypes were observed. At 2.5 nM sagopilone or 4 nM paclitaxel an aneuploid phenotype occur whereas a mitotic arrest phenotype was induced by 40 nM sagopilone or paclitaxel. Interestingly, treatment with 2.5 nM of sagopilone effectively inhibited cell proliferation, but--compared to high concentrations (40 nM)--only marginally induced apoptosis. Treatment with a high versus a low concentration of sagopilone or paclitaxel regulates a non-overlapping set of genes, indicating that both phenotypes substantially differ from each other. Genes involved in G2/M phase transition and the spindle assembly checkpoint, like Cyclin B1 and BUBR1 were upregulated by treatment with 40 nM sagopilone. Unexpectedly, also genes involved in DNA damage response were upregulated under that treatment. In contrast, treatment of A549 cells with a low concentration of sagopilone revealed an upregulation of direct transcriptional target genes of TP53, like CDKN1A, MDM2, GADD45A, FAS. Knockdown of TP53, which inhibited the transcriptional induction of TP53 target genes, led to a significant increase in apoptosis induction in A549 cells when treated with a low concentration of sagopilone. The results indicate that activation of TP53 and its downstream effectors like CDKN1A by low concentrations of sagopilone is responsible for the relative apoptosis resistance of A549 cells and might represent a mechanism of resistance to sagopilone.

Topics: Antineoplastic Agents; Apoptosis; Benzothiazoles; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cytoskeleton; DNA Damage; Epothilones; Humans; In Vitro Techniques; Lung Neoplasms; Oligonucleotide Array Sequence Analysis; Paclitaxel; Phenotype; Tumor Suppressor Protein p53; Up-Regulation

The metabolic switch to aerobic glycolysis (Warburg effect) and enhanced lactate production is characteristic for aggressive tumor cells and is a co-determining factor for tumor response and treatment outcome. Thus analysis of the metabolic status under treatment is important to understand and improve treatment modalities.. Metabolite concentrations were determined by the immersion of tumor sections in an ATP, lactate or glucose-depending luciferase-containing buffer system. Integrated light output is detected in a bioluminescent detection system.. Mice carrying tumor xenografts derived from A549 lung cancer cells were treated with the microtubule stabilizing agent patupilone, ionizing radiation or in combination. Lactate levels were significantly reduced and glucose levels drastically increased in comparison to untreated tumors. Interestingly, these changes were only minimal in tumors derived from patupilone-resistant but otherwise isogenic A549EpoB40 cells. ATP levels of all tumors tested did not change under any treatment. When compared with histological endpoints, basal and treatment-dependent changes of lactate levels in the different tumors mainly correlated with the proliferative activity and the tumor growth response to treatment.. This study shows that the tumor metabolism is responsive to different treatment modalities and could eventually be used as an early surrogate marker for treatment response.

Topics: Adenosine Triphosphate; Animals; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Epothilones; Glycolysis; Humans; Lactic Acid; Luciferases; Luminescent Measurements; Lung Neoplasms; Mice; Mice, Nude; Transplantation, Heterologous; Tumor Microenvironment

Epothilones are a new class of microtubule stabilizing agents with promising preclinical and clinical activity. Their cellular target is β-tubulin and factors influencing intrinsic sensitivity to epothilones are not well understood. In this study, the functional significance of specific β-tubulin isotypes in intrinsic sensitivity to epothilone B was investigated using siRNA gene knockdown against βII-, βIII- or βIVb-tubulins in two independent non-small cell lung cancer (NSCLC) cell lines, NCI-H460 and Calu-6. Drug-treated clonogenic assays showed that sensitivity to epothilone B was not altered following knockdown of βII-tubulin in both NSCLC cell lines. In contrast, knockdown of βIII-tubulin significantly increased sensitivity to epothilone B. Interestingly, βIVb-tubulin knockdowns were significantly less sensitive to epothilone B, compared to mock- and control siRNA cells. Cell cycle analysis of βIII-tubulin knockdown cells showed a higher percentage of cell death with epothilone B concentrations as low as 0.5 nM. In contrast, βIVb-tubulin knockdown cells displayed a decrease in epothilone B-induced G(2)-M cell cycle accumulation compared to control siRNA cells. Importantly, βIII-tubulin knockdowns displayed a significant dose-dependent increase in the percentage of apoptotic cells upon treatment with epothilone B, as detected using caspase 3/7 activity and Annexin-V staining. Higher concentrations of epothilone B were required to induce apoptosis in the βIVb-tubulin knockdowns compared to control siRNA, highlighting a potential mechanism underlying decreased sensitivity to this agent. This study demonstrates that specific β-tubulin isotypes can influence sensitivity to epothilone B and may influence differential sensitivity to this promising new agent.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Drug Resistance, Neoplasm; Epothilones; Humans; Tubulin

Characterization of new anticancer drugs in a few xenograft models derived from established human cancer cell lines frequently results in the discrepancy between preclinical and clinical results. To take the heterogeneity of tumors into consideration more thoroughly, we describe here a preclinical approach that may allow a more rational clinical development of new anticancer drugs.. We tested Sagopilone, an optimized fully synthetic epothilone, in 22 well-characterized patient-derived non-small cell lung cancer models and correlated results with mutational and genome-wide gene expression analysis.. Response analysis according to clinical trial criteria revealed that Sagopilone induced overall responses in 64% of the xenograft models (14 of 22), with 3 models showing stable disease and 11 models showing partial response. A comparison with response rates for established drugs showed the strong efficacy of Sagopilone in non-small cell lung cancer. In gene expression analyses, Sagopilone induced tubulin isoforms in all tumor samples, but genes related to mitotic arrest only in responder models. Moreover, tumors with high expression of genes involved in cell adhesion/angiogenesis as well as of wild-type TP53 were more likely to be resistant to Sagopilone therapy. As suggested by these findings, Sagopilone was combined with Bevacizumab and Sorafenib, drugs targeting vascular endothelial growth factor signaling, in Sagopilone-resistant models and, indeed, antitumor activity could be restored.. Analyses provided here show how preclinical studies can provide hypotheses for the identification of patients who more likely will benefit from new drugs as well as a rationale for combination therapies to be tested in clinical trials.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Benzenesulfonates; Benzothiazoles; Bevacizumab; Carcinoma, Non-Small-Cell Lung; Drug Resistance, Neoplasm; Epothilones; Gene Expression Profiling; Humans; Lung Neoplasms; Mice; Niacinamide; Phenylurea Compounds; Pyridines; Reverse Transcriptase Polymerase Chain Reaction; Sorafenib; Xenograft Model Antitumor Assays

Topics: Carcinoma, Non-Small-Cell Lung; Clinical Trials as Topic; Epothilones; Humans; Lung Neoplasms; Taxoids; Tubulin Modulators

The combined treatment modality of ionizing radiation (IR) and the clinically relevant microtubule-stabilizing compound patupilone (epothilone B, EPO906) is a promising approach for anticancer therapy. Here, we investigated the role of the tumor microenvironment for the supra-additive in vivo response in tumor xenografts derived from patupilone-sensitive and patupilone-resistant non-small cell lung cancer cells.. The treatment response to a combined regimen of patupilone and IR was investigated in vitro and in tumor xenografts derived from wild-type A549 and A549.EpoB40 cells, which are resistant to patupilone due to a beta-tubulin mutation.. In both A549 and A549.EpoB40 cells, proliferative activity and clonogenicity were reduced in response to IR, whereas patupilone, as expected, inhibited proliferation of the mutant cell line with reduced potency. Combined treatment with patupilone and IR induced a cytotoxic effect in vitro in an additive way in A549 cells but not in the tubulin-mutated, patupilone-resistant A549.EpoB40 cells. A supra-additive tumor growth delay was induced by combined treatment in xenografts derived from A549 cells but not in xenografts derived from A549.EpoB40 cells. Histologic analysis revealed a significant decrease in tumor cell proliferation (Ki-67) and microvessel density and a treatment-dependent change of tumor hypoxia in A549 but not A549.EpoB40 xenografts.. Using a genetically defined patupilone-sensitive and patupilone-resistant tumor model, we here showed that the major cytotoxic effect of the combined treatment modality of IR and patupilone is directed against the tumor cell compartment. The induced antiangiogenic effect derives indirectly from the tumor cell.

Topics: Animals; Carcinoma, Non-Small-Cell Lung; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Epothilones; Humans; Lung Neoplasms; Mice; Neovascularization, Pathologic; Radiation-Sensitizing Agents; Xenograft Model Antitumor Assays

Topics: Antineoplastic Agents; Breast Neoplasms; Carcinoma, Non-Small-Cell Lung; Chemistry, Pharmaceutical; Clinical Trials as Topic; Drug Design; Epothilones; Female; Humans; Lung Neoplasms; Neoplasms; Tubulin

We have previously reported that the microtubule stabilizing agents (MSAs) paclitaxel, epothilone B and discodermolide induce caspase-independent cell death in non-small cell lung cancer (NSCLC) cells. Here we present two lines of evidence indicating a central role for the lysosomal protease cathepsin B in mediating cell death. First, inhibition of cathepsin B, and not of caspases or other proteases, such as cathepsin D or calpains, results in a strong protection against drug-induced cell death in several NSCLC cells. Second, MSAs trigger disruption of lysosomes and release and activation of cathepsin B. Interestingly, inhibition of cathepsin B prevents the appearance of multinucleated cells, an early characteristic of MSA-induced cell death, pointing to a central, proximal role for cathepsin B in this novel cell death pathway.

Topics: Alkanes; Antineoplastic Agents; Apoptosis; Base Sequence; Carbamates; Carcinoma, Non-Small-Cell Lung; Caspases; Cathepsin B; Cell Death; DNA Primers; Epothilones; Humans; Lactones; Lung Neoplasms; Lysosomes; Microscopy, Fluorescence; Microtubules; Paclitaxel; Pyrones; Transfection; Tumor Cells, Cultured

To explore the molecular mechanisms underlying the actions of Taxol and the functionally related molecule epothilone B (EpoB), we have analyzed the gene expression profiles in A549 cells in response to increasing concentrations of these microtubule-stabilizing drugs. An almost identical expression pattern was observed in cells treated with either Taxol or EpoB. Low concentrations of the drugs induced aberrant mitosis including asymmetric and multipolar cell divisions. At drug concentrations that triggered G(2)-M arrest, cells escaped from a prolonged mitotic arrest without cell division, resulting in tetraploid G(1) cells. This mitotic slippage is correlated with diminished expression of cdc2 kinase, topoisomerase IIalpha, BUB3, and BUB2-like protein 1, as well as with an increased expression of 14-3-3-sigma. Poly(ADP-ribose) polymerase cleavage, an early indicator of apoptosis, occurred in cells undergoing mitotic slippage and in aneuploid cells resulting from aberrant mitosis. In contrast, cells arrested in mitosis demonstrated no signal for apoptosis but had an increased expression of survivin, an inhibitor of apoptosis. Induction of aneuploid or tetraploid G(1) cells was accompanied by increased expression of CD95, p21, and BTG2 that may contribute to cell death because their expression was diminished in an EpoB-resistant cell line. In contrast, expression of GADD45 and PTGF-beta could promote cell survival. We conclude that abnormal mitotic exit is required for apoptotic cell death induced by microtubule-stabilizing drugs.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Epothilones; Gene Expression; Gene Expression Profiling; Humans; Lung Neoplasms; Microtubules; Mitosis; Oligonucleotide Array Sequence Analysis; Paclitaxel; Polyploidy; RNA, Messenger

Discodermolide and epothilone B are promising novel chemotherapeutic agentsthat induce cell death through potent stabilization of microtubules. In this study, we investigated the cellular and molecular events underlying the cytotoxicity of these drugs in non-small cell lung carcinoma (NSCLC) cell lines, focusing on apoptotic characteristics. IC80 concentrations of either drug effectively disrupted the microtubule cytoskeleton of H460 cells and induced cell cycle disturbances with early accumulation in the G2-M phase and development of a hypodiploid cell population in both H460 and SW1573 cells. These events were followed by abnormal chromosome segregation during mitosis and subsequent appearance of multinucleated cells. At later time points, the cells displayed several apoptotic features, such as nuclear condensation and fragmentation as well as Annexin V staining, cleavage of poly(ADP-ribose) polymerase and the activation of caspases. To examine the contribution of apoptotic pathways to the cytotoxic effects of these agents, the involvement of the mitochondria and death receptor routes was studied. At 48 h after treatment, both agents disrupted mitochondria of H460 cells, as indicated by cytochrome c release. Nonetheless, H460 cells stably overexpressing antiapoptotic Bcl-2 or Bcl-xL did not show any protective effect from cell death induced by either drug. Possible death receptor dependency was investigated in H460 cells stably overexpressing dominant-negative FADD, which failed to reduce the cytotoxic effects of discodermolide and epothilone B. To study the role of caspases more directly, the effect of stable overexpression of the caspase-8 inhibitor cytokine response modifier A was studied in H460 cells. Furthermore, the effect of the pancaspase inhibitor z-Val-Ala-Asp-fluoromethyl ketone was investigated in a panel of lung carcinoma cell lines. Interestingly, caspase inhibition did not rescue cells from discodermolide or epothilone B-induced cell death. In conclusion, these results demonstrate that despite several apoptotic features detected at relatively late time points after drug exposure, apoptosis is not the dominant mode of cell death and induced low but efficacious concentrations of discodermolide and epothilone B.

Topics: Alkanes; Antineoplastic Agents; Apoptosis; Carbamates; Carcinoma, Non-Small-Cell Lung; Caspase Inhibitors; Caspases; Epothilones; Humans; Inhibitory Concentration 50; Jurkat Cells; Lactones; Lung Neoplasms; Macrolides; Mitochondria; Pyrones; Receptors, Tumor Necrosis Factor; Tumor Cells, Cultured

Although microtubule interacting agents inhibit spindle dynamics, thereby leading to a block in mitosis, we report that low concentrations of these drugs result in differential mitotic effects. Microtubule-stabilizing agents including Taxol, epothilone B, and discodermolide produce aneuploid populations of A549 cells in the absence of a mitotic block. Such aneuploid populations are diminished in an epothilone B-resistant cell line. In contrast, microtubule-destabilizing agents like colchicine, nocodazole, and vinblastine are unable to initiate aneuploidy. The aneuploid cells result from aberrant mitosis as multipolar spindles are induced by the stabilizing drugs, but not by destabilizing agents. The results suggest that the mechanism underlying aberrant mitosis may not be the same as that responsible for mitotic block, and that the former determines the sensitivity of cells to Taxol-like drugs.

Topics: Alkanes; Aneuploidy; Antineoplastic Agents; Carbamates; Carcinoma, Non-Small-Cell Lung; Epothilones; Humans; Lactones; Lung Neoplasms; Macrolides; Microtubules; Mitosis; Paclitaxel; Pyrones; Spindle Apparatus; Tumor Cells, Cultured