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Michael Lahn - One of the best experts on this subject based on the ideXlab platform.

  • a window of opportunity phase ii study of Enzastaurin in chemonaive patients with asymptomatic metastatic colorectal cancer
    Annals of Oncology, 2010
    Co-Authors: Luna Musib, Christelle Darstein, Michael Lahn, Ann Cleverly, Bengt Glimelius, S Gawande, Y Liu, K L Spindler, J E Frodin
    Abstract:

    BACKGROUND: Preclinically, protein kinase C and AKT activation can be inhibited by Enzastaurin and reduce tumor growth of colorectal cancer cells. In asymptomatic patients with metastatic colorectal cancer (mCRC), Enzastaurin activity was evaluated by measuring the 6-month progression-free survival (PFS) rate in a window study design. PATIENTS AND METHODS: Chemonaive patients with asymptomatic mCRC who did not require immediate chemotherapy-induced tumor reduction received a 400-mg thrice daily loading dose of Enzastaurin on day 1 of cycle 1, followed by 500 mg once daily for the remaining 28-day cycles. Progression was assessed on the basis of radiographic imaging, rise in carcinoembryonic antigen or lactate dehydrogenase (LDH) levels or by appearance of clinical symptoms. RESULTS: Twenty-eight patients received daily Enzastaurin. The 6-month PFS rate was 28% [95% confidence interval (CI) 13%-45%] and median PFS was 1.9 months (95% CI 1.8-4.5 months). Twelve (43%) patients had stable disease with a median duration of 6.1 months. The survival rate at 20 months was 77% (95% CI 47%-92%). No grade 4 toxicity was reported and grade 3 toxic effects were observed in three patients with one patient showing probable drug-related elevation of liver transaminases. CONCLUSION: The window design in asymptomatic patients with mCRC can be safely applied to assess the activity and safety of novel cytostatic agents like Enzastaurin.

  • phase ib safety and pharmacokinetic evaluation of daily and twice daily oral Enzastaurin in combination with pemetrexed in advanced metastatic cancer
    Annals of Oncology, 2009
    Co-Authors: Axel Hanauske, Luna Musib, Michael Lahn, K Weigangkohler, E Yilmaz, T Graefe, B Kuenen, Donald Thornton, P Mcnealy, Giuseppe Giaccone
    Abstract:

    BACKGROUND This phase Ib study evaluated the safety, pharmacokinetics, and activity of Enzastaurin either 500 mg once daily (QD) or 250 mg twice daily (b.i.d.) in combination with pemetrexed. PATIENTS AND METHODS Pemetrexed 500 mg/m(2) with folic acid and vitamin B(12) was given on day 1 every 21 days with Enzastaurin 500 mg orally QD starting on day 5 of cycle 1 after a loading dose of 400 mg thrice daily on day 4. To evaluate whether a b.i.d. regimen results in higher Enzastaurin exposures, the study was amended. After amendment, in cycle 1, patients received 500 mg Enzastaurin QD on days 1-15 without initial loading dose and 250 mg b.i.d. on days 16-30; in subsequent cycles, patients received pemetrexed on day 1 every 21 days with Enzastaurin b.i.d. RESULTS Sixty-eight patients (42 preamendment and 26 postamendment) were assessed. Pemetrexed toxicity and pharmacokinetics did not appear to be altered by Enzastaurin. Enzastaurin average steady-state plasma concentration (C(av,ss)) decreased by approximately 25% in the presence of pemetrexed. Enzastaurin C(av,ss) were approximately 40% higher in the b.i.d. versus QD regimen. Three patients (4.4%) with thyroid cancer of follicular/papillary type had partial response as defined by RECIST. CONCLUSIONS Pemetrexed plus Enzastaurin is well tolerated with preliminary evidence of anticancer activity, particularly in thyroid cancer.

  • in vivo measurements of tumor metabolism and growth after administration of Enzastaurin using small animal fdg positron emission tomography
    Journal of Oncology, 2009
    Co-Authors: Karen E Pollok, Jeremy R Graff, Ann M Mcnulty, Michael Lahn, Donald Thornton, Nathan Enas, Shanbao Cai, Jennifer R Hartwell, Aaron Ernstberger, Les Brail
    Abstract:

    Background. The use of 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) may help to establish the antitumor activity of Enzastaurin, a novel protein kinase C-beta II (PKC-

  • Enzastaurin inhibits tumours sensitive and resistant to anti egfr drugs
    British Journal of Cancer, 2008
    Co-Authors: Teresa Gelardi, Michael Lahn, Stefano Pepe, Fortunato Ciardiello, R Caputo, Vincenzo Damiano, Gennaro Daniele, Roberto Bianco, Giampaolo Tortora
    Abstract:

    We investigated the antitumour effect and ability to overcome the resistance to anti-EGFR drugs of Enzastaurin, an inhibitor of VEGFR-dependent PKCβ signalling. Enzastaurin was evaluated alone and in combination with the EGFR inhibitor gefitinib, on growth and signalling protein expression in human cancer cells sensitive and resistant to anti-EGFR drugs, both in vitro and in nude mice. We demonstrated the marked inhibitory activity of Enzastaurin against GEO colon and PC3 prostate cancer cells and their gefitinib-resistant counterparts GEO-GR and PC3-GR, accompanied by inhibition of pAkt and its effector pp70S6K, pGSK3β and VEGF expression and secretion. Moreover, Enzastaurin showed a cooperative effect with gefitinib in parental and in gefitinib-resistant cells. Remarkably, these results were confirmed in vivo, where Enzastaurin showed antitumour activity and cooperativity with gefitinib in mice grafted with GEO and GEO-GR tumours, incrementing their median survival and inhibiting the aforesaid protein expression and secretion in tumour specimens. In conclusion, Enzastaurin by interfering with signalling proteins implicated in EGFR drug resistance markedly cooperates with gefitinib in sensitive and gefitinib-resistant tumours, thus overcoming and reverting such resistance and providing a rational basis for its development in patients resistant to anti-EGFR drugs.

  • Correlations of mRNA expression and in vitro chemosensitivity to Enzastaurin in freshly explanted human tumor cells
    Investigational New Drugs, 2008
    Co-Authors: Axel-rainer Hanauske, Olaf Oberschmidt, Ulrike Eismann, Heike Pospisil, Hartmut M. Hanauske-abel, Johannes Blatter, Victor Chen, Michael Lahn
    Abstract:

    Purpose: Enzastaurin (LY317615) is a novel serine/threonine kinase inhibitor, targeting Protein Kinase C-beta (PKC-β), and PI3K/AKT pathways to inhibit angiogenesis and tumor cell proliferation. The aims of this study were to determine whether Enzastaurin has direct antitumor activity against freshly explanted tumor cells and to correlate mRNA expression of genes related to the proposed mechanism of action of Enzastaurin with in vitro chemosensitivity. Experimental Design: Freshly biopsied tumor cells were studied using soft-agar cell cloning experiments (SACCE) to determine the in vitro chemosensitivity to Enzastaurin. An aliquot of the same tumor specimens was shock-frozen and total RNA was isolated for standardized multiplex rt-PCR experiments for gene expression of PKC-β1, PKC-β2, IL-8, IL-8RA, IL-8RB, Glycogen Synthase Kinase 3 beta (GSK-3β) and TGF-β1. Correlations, threshold optimization, sensitivity, specificity, and efficiency were analyzed using the appropriate statistical methodologies. Results: Seventy-two tumor samples were collected and 63 were fully evaluable. Low levels of mRNA expression of GSK-3β and high levels of mRNA expression of IL-8 were highly significantly correlated with chemosensitivity to Enzastaurin. Optimization analyses demonstrated threshold values of 4,000 copies for IL-8 and three copies for GSK-3β relative to 10^4 copies of β-actin. However, no correlation between mRNA expression of PKC-β1, PKC-β2, IL-8RA, IL-8RB and chemosensitivity to Enzastaurin was observed. Expression of TGF-β1 mRNA was not detectable in the specimens investigated. Conclusions: mRNA expression levels of IL-8 and GSK-3β correlate with antitumor activity of Enzastaurin. These results form a rational basis for clinical trials to evaluate the expression of these genes as potential predictors for treatment outcome after Enzastaurin chemotherapy.

Luna Musib - One of the best experts on this subject based on the ideXlab platform.

  • Phase I Dose Escalation and Pharmacokinetic Study of Enzastaurin, an Oral Protein Kinase C Beta Inhibitor, in Patients With Advanced Cancer
    2016
    Co-Authors: Michael A Carducci, Luna Musib, Merrill S. Kies, Roberto Pili, Mylene Truong, Julie R. Brahmer, Patricia Cole, Rana Sullivan, Jeanne Riddle, Jill Schmidt
    Abstract:

    This phase I study was conducted to determine the recommended dose of Enzastaurin, an oral protein kinase C beta (PKC) inhibitor, for phase II trials. Secondary objectives were maximum-tolerated dose (MTD), pharmacokinetics (PK), toxicity, and response. Patients and Methods Patients at least 18 years of age with advanced cancer and an Eastern Cooperative Oncology Group performance status of 0 or 1 lower received Enzastaurin orally once daily at a starting dose of 20 mg. Dose escalation proceeded using a modified Simon design. Results All 47 patients enrolled (mean age, 58 years) received at least one dose of Enzastaurin, with a median of two cycles (range, one to 17 cycles). Prevalent malignancies were lung (n 10) and head and neck cancers (n 9). Although no MTD was identified up to 700 mg/d, 525 mg was chosen as the recommended dose, and 12 additional patients were accrued at that level. Three dose-limiting toxicities (QTc changes) occurred: one at the 700-mg dose (patient discontinued), and two in the expansion cohort at the 525-mg dose. Total analytes (Enzastaurin and its metabolites) exposure increased with increasing doses up to 240 mg, and appeared to plateau at 525 and 700 mg. Grade 1 chromaturia, fatigue, and other GI toxicities were the most common, while no clinically significant grade 3/4 toxicities occurred. Two deaths, unrelated to Enzastaurin, occurred. Twenty-one patients (45%) achieved stable disease (SD) for two to 16 cycles. Conclusion On the basis of plasma exposures and safety data, Enzastaurin 525 mg once daily is the recommended phase II dose. Enzastaurin is well tolerated up to 700 mg/d. Evidence of early activity was seen with significant stable disease. J Clin Oncol 24:4092-4099. © 2006 by American Society of Clinical Oncolog

  • a window of opportunity phase ii study of Enzastaurin in chemonaive patients with asymptomatic metastatic colorectal cancer
    Annals of Oncology, 2010
    Co-Authors: Luna Musib, Christelle Darstein, Michael Lahn, Ann Cleverly, Bengt Glimelius, S Gawande, Y Liu, K L Spindler, J E Frodin
    Abstract:

    BACKGROUND: Preclinically, protein kinase C and AKT activation can be inhibited by Enzastaurin and reduce tumor growth of colorectal cancer cells. In asymptomatic patients with metastatic colorectal cancer (mCRC), Enzastaurin activity was evaluated by measuring the 6-month progression-free survival (PFS) rate in a window study design. PATIENTS AND METHODS: Chemonaive patients with asymptomatic mCRC who did not require immediate chemotherapy-induced tumor reduction received a 400-mg thrice daily loading dose of Enzastaurin on day 1 of cycle 1, followed by 500 mg once daily for the remaining 28-day cycles. Progression was assessed on the basis of radiographic imaging, rise in carcinoembryonic antigen or lactate dehydrogenase (LDH) levels or by appearance of clinical symptoms. RESULTS: Twenty-eight patients received daily Enzastaurin. The 6-month PFS rate was 28% [95% confidence interval (CI) 13%-45%] and median PFS was 1.9 months (95% CI 1.8-4.5 months). Twelve (43%) patients had stable disease with a median duration of 6.1 months. The survival rate at 20 months was 77% (95% CI 47%-92%). No grade 4 toxicity was reported and grade 3 toxic effects were observed in three patients with one patient showing probable drug-related elevation of liver transaminases. CONCLUSION: The window design in asymptomatic patients with mCRC can be safely applied to assess the activity and safety of novel cytostatic agents like Enzastaurin.

  • phase iii study of Enzastaurin compared with lomustine in the treatment of recurrent intracranial glioblastoma
    Journal of Clinical Oncology, 2010
    Co-Authors: Wolfgang Wick, Martin J Van Den Bent, Vinay K Puduvalli, Marc C Chamberlain, Antoine F Carpentier, Lawrence Cher, Warren P Mason, Michael Weller, Shengyan Hong, Luna Musib
    Abstract:

    Purpose This phase III open-label study compared the efficacy and safety of Enzastaurin versus lomustine in patients with recurrent glioblastoma (WHO grade 4). Patients and Methods Patients were randomly assigned 2:1 to receive 6-week cycles of Enzastaurin 500 mg/d (1,125-mg loading dose, day 1) or lomustine (100 to 130 mg/m2, day 1). Assuming a 45% improvement in progression-free survival (PFS), 397 patients were required to provide 80% power to achieve statistical significance at a one-sided level of .025. Results Enrollment was terminated at 266 patients (Enzastaurin, n = 174; lomustine, n = 92) after a planned interim analysis for futility. Patient characteristics were balanced between arms. Median PFS (1.5 v 1.6 months; hazard ratio [HR] = 1.28; 95% CI, 0.97 to 1.70), overall survival (6.6 v 7.1 months; HR = 1.20; 95% CI, 0.88 to 1.65), and 6-month PFS rate (P = .13) did not differ significantly between Enzastaurin and lomustine, respectively. Stable disease occurred in 38.5% and 35.9% of patients an...

  • carboplatin and paclitaxel in combination with oral Enzastaurin in advanced ovarian or primary peritoneal cancer results from a safety lead in study
    International Journal of Gynecological Cancer, 2009
    Co-Authors: Ignace Vergote, Marek Kania, Luna Musib, Christelle Darstein, Frederic Amant, G Oskayoezcelik, Annelaure Michel, T Bauknecht, Jalid Sehouli
    Abstract:

    Introduction This safety lead-in study examined the pharmacokinetic and adverse event profile of combining Enzastaurin with paclitaxel plus carboplatin as first-line therapy for the treatment of advanced-stage ovarian cancer and primary peritoneal carcinoma. The specific objectives of this study were to assess safety and tolerability after 2 cycles of treatment, to determine if Enzastaurin alters paclitaxel and carboplatin pharmacokinetics, and to determine if Enzastaurin pharmacokinetics is affected by paclitaxel and carboplatin. Methods After debulking surgery, patients with previously untreated epithelial ovarian or primary peritoneal carcinoma received sequential paclitaxel (175 mg/m) and carboplatin (area under the curve, 5 mg x min/mL) on day 1 every 3 weeks for 6 cycles. Patients ingested an oral loading dose of 1125 mg Enzastaurin on day 4 of cycle 1, followed by oral 500-mg Enzastaurin daily until the end of therapy. Adverse events were graded according to the Common Terminology Criteria for Adverse Events v3.0. Results There were 5 serious adverse events in 4 of 11 patients: soft tissue injury, wound infection, intestinal fistula, clostridial infection, and anemia. Coadministration with Enzastaurin did not significantly alter paclitaxel and carboplatin pharmacokinetics (area under the curve ratio of treatment comparison asymptotically equal to 1.05 and 1.06, respectively). Enzastaurin exposures were unchanged (Cav,ss ratio of treatment comparison asymptotically equal to 0.95 for average steady-state total analyte concentrations of Enzastaurin and its metabolite). Conclusions Adding Enzastaurin to paclitaxel plus carboplatin chemotherapy is feasible for advanced ovarian cancer after radical cytoreduction. Enzastaurin did not alter paclitaxel or carboplatin pharmacokinetics, and Enzastaurin exposures were not significantly changed by carboplatin and paclitaxel.

  • phase ib safety and pharmacokinetic evaluation of daily and twice daily oral Enzastaurin in combination with pemetrexed in advanced metastatic cancer
    Annals of Oncology, 2009
    Co-Authors: Axel Hanauske, Luna Musib, Michael Lahn, K Weigangkohler, E Yilmaz, T Graefe, B Kuenen, Donald Thornton, P Mcnealy, Giuseppe Giaccone
    Abstract:

    BACKGROUND This phase Ib study evaluated the safety, pharmacokinetics, and activity of Enzastaurin either 500 mg once daily (QD) or 250 mg twice daily (b.i.d.) in combination with pemetrexed. PATIENTS AND METHODS Pemetrexed 500 mg/m(2) with folic acid and vitamin B(12) was given on day 1 every 21 days with Enzastaurin 500 mg orally QD starting on day 5 of cycle 1 after a loading dose of 400 mg thrice daily on day 4. To evaluate whether a b.i.d. regimen results in higher Enzastaurin exposures, the study was amended. After amendment, in cycle 1, patients received 500 mg Enzastaurin QD on days 1-15 without initial loading dose and 250 mg b.i.d. on days 16-30; in subsequent cycles, patients received pemetrexed on day 1 every 21 days with Enzastaurin b.i.d. RESULTS Sixty-eight patients (42 preamendment and 26 postamendment) were assessed. Pemetrexed toxicity and pharmacokinetics did not appear to be altered by Enzastaurin. Enzastaurin average steady-state plasma concentration (C(av,ss)) decreased by approximately 25% in the presence of pemetrexed. Enzastaurin C(av,ss) were approximately 40% higher in the b.i.d. versus QD regimen. Three patients (4.4%) with thyroid cancer of follicular/papillary type had partial response as defined by RECIST. CONCLUSIONS Pemetrexed plus Enzastaurin is well tolerated with preliminary evidence of anticancer activity, particularly in thyroid cancer.

Roy S Herbst - One of the best experts on this subject based on the ideXlab platform.

  • Enzastaurin an oral serine threonine kinase inhibitor as second or third line therapy of non small cell lung cancer
    Journal of Clinical Oncology, 2008
    Co-Authors: Roy S Herbst, Luna Musib, Michael Lahn, Ann Cleverly, Howard Burris, Gerold Bepler
    Abstract:

    Purpose Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses protein kinase C (PKC) and protein kinase B/AK transforming (AKT) signaling, induces tumor cell apoptosis, and inhibits proliferation and angiogenesis. Increased PKC and AKT activity is associated with poor prognosis in non–small-cell lung cancer (NSCLC). This phase II trial of Enzastaurin was conducted to determine the 6-month progression-free survival (PFS) rate in advanced, metastatic NSCLC. Patients and Methods Patients with metastatic (stage IV and wet IIIB) NSCLC, Eastern Cooperative Oncology Group performance status ≤ 2, and ≤ two prior systemic regimens (including one or more platinum-based chemotherapy regimens) received 500 mg of Enzastaurin administered once daily. Results Fifty-five patients were enrolled (55% male patients, 45% female patients; median age, 63 years; range, 44 to 82 years; 78% of patients having stage IV disease). Adenocarcinoma was the most common diagnosis (65%). Prior therapies included radiotherapy ...

  • Enzastaurin a protein kinase cβ selective inhibitor and its potential application as an anticancer agent in lung cancer
    Clinical Cancer Research, 2007
    Co-Authors: Roy S Herbst, Asavari Wagle, Michael Lahn
    Abstract:

    Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through protein kinase C (PKC)-β and the phosphatidylinositol 3-kinase/AKT pathway to induce tumor cell apoptosis, reduce proliferation, and suppress tumor-induced angiogenesis. In contrast to previous PKC inhibitors, Enzastaurin is very well tolerated with a favorable safety profile, allowing it to be dosed for extended durations. In the present review, we summarize the rationale for targeting PKC in cancer, the preclinical experience of Enzastaurin, and the clinical findings of the current phase I and II studies. Based on the combined information, we present the rationale for its future assessment in the treatment of lung cancer.

  • development and validation of a drug activity biomarker that shows target inhibition in cancer patients receiving Enzastaurin a novel protein kinase c β inhibitor
    Clinical Cancer Research, 2006
    Co-Authors: Lisa J Green, Luna Musib, Philip Marder, Carolyn A Cook, Susan Jaken, Roy S Herbst, Michael A Carducci, Carolyn D Britten, Michele Basche, Gail S Eckhardt
    Abstract:

    Purpose: To evaluate the effects of the novel protein kinase C (PKC) inhibitor Enzastaurin on intracellular phosphoprotein signaling using flow cytometry and to use this approach to measure Enzastaurin effects on surrogate target cells taken from cancer patients that were orally dosed with this agent. Experimental Design: The activity of PKC was assayed in intact cells using a modification of published techniques. The U937 cell line and peripheral blood mononuclear cells were stimulated with phorbol ester, fixed, permeabilized, and reacted with an antibody specific for the phosphorylated forms of PKC substrates. The processed samples were quantitatively analyzed using flow cytometry. The assay was validated for selectivity, sensitivity, and reproducibility. Finally, blood was obtained from volunteer cancer patients before and after receiving once daily oral doses of Enzastaurin. These samples were stimulated ex vivo with phorbol ester and were assayed for PKC activity using this approach. Results: Assay of U937 cells confirmed the selectivity of the antibody reagent and Enzastaurin for PKC. Multiparametric analysis of peripheral blood mononuclear cells showed monocytes to be the preferred surrogate target cell. Day-to-day PKC activity in normal donors was reproducible. Initial results showed that five of six cancer patients had decreased PKC activity following Enzastaurin administration. In a following study, a group of nine patients displayed a significant decrease in PKC activity after receiving once daily oral doses of Enzastaurin. Conclusion: An inhibition of surrogate target cell PKC activity was observed both in vitro and ex vivo after exposure to the novel kinase inhibitor, Enzastaurin.

  • development and validation of a drug activity biomarker that shows target inhibition in cancer patients receiving Enzastaurin a novel protein kinase c β inhibitor
    Clinical Cancer Research, 2006
    Co-Authors: Lisa J Green, Luna Musib, Philip Marder, Carolyn A Cook, Susan Jaken, Roy S Herbst, Michael A Carducci, Carolyn D Britten, Chad Ray, Michele Basche
    Abstract:

    Purpose: To evaluate the effects of the novel protein kinase C (PKC) inhibitor Enzastaurin on intracellular phosphoprotein signaling using flow cytometry and to use this approach to measure Enzastaurin effects on surrogate target cells taken from cancer patients that were orally dosed with this agent. Experimental Design: The activity of PKC was assayed in intact cells using a modification of published techniques. The U937 cell line and peripheral blood mononuclear cells were stimulated with phorbol ester, fixed, permeabilized, and reacted with an antibody specific for the phosphorylated forms of PKC substrates. The processed samples were quantitatively analyzed using flow cytometry. The assay was validated for selectivity, sensitivity, and reproducibility. Finally, blood was obtained from volunteer cancer patients before and after receiving once daily oral doses of Enzastaurin. These samples were stimulated ex vivo with phorbol ester and were assayed for PKC activity using this approach. Results: Assay of U937 cells confirmed the selectivity of the antibody reagent and Enzastaurin for PKC. Multiparametric analysis of peripheral blood mononuclear cells showed monocytes to be the preferred surrogate target cell. Day-to-day PKC activity in normal donors was reproducible. Initial results showed that five of six cancer patients had decreased PKC activity following Enzastaurin administration. In a following study, a group of nine patients displayed a significant decrease in PKC activity after receiving once daily oral doses of Enzastaurin. Conclusion: An inhibition of surrogate target cell PKC activity was observed both in vitro and ex vivo after exposure to the novel kinase inhibitor, Enzastaurin.

Godefridus J Peters - One of the best experts on this subject based on the ideXlab platform.

  • molecular mechanism underlying the pharmacological interactions of the protein kinase c β inhibitor Enzastaurin and erlotinib in non small cell lung cancer cells
    American Journal of Cancer Research, 2017
    Co-Authors: Nele Van Der Steen, Elisa Giovannetti, Lisette Potze, Andrea Cavazzoni, Rob Ruijtenbeek, Christian Rolfo, Patrick Pauwels, Godefridus J Peters
    Abstract:

    Erlotinib is commonly used as a second line treatment in non-small cell lung cancer patients with sensitizing EGFR mutations. In EGFR-wild type patients, however the results are limited. Therefore we evaluated whether the combination of the Protein kinase C-β inhibitor Enzastaurin with erlotinib could enhance the effect in the A549 and H1650 cell lines. Cytotoxicity of erlotinib, Enzastaurin and their 72-h simultaneous combination was assessed with the MTT assay. The pharmacologic interaction was studied using the method of Chou and Talalay, cell cycle perturbations were assessed by flow cytometry and modulation of ERK1/2 and AKT phosphorylation was determined with ELISA. For protein phosphorylation of GSK3β we performed Western Blot analysis and a Pamgene phosphorylation array, while RT-PCR was used to investigate VEGF and VEGFR-2 expression before and after drug treatments. A synergistic interaction was found in both cell lines with mean CI of 0.58 and 0.63 in A549 and H1650 cells, respectively. Enzastaurin alone and in combination with erlotinib increased the percentage of cells in S and G2M phase, mostly in H1650 cells, while AKT, ERK1/2 and GSK3β phosphorylation were reduced in both cell lines. VEGF expression decreased 5.0 and 6.9 fold in A549 cells after Enzastaurin alone and with erlotinib, respectively, while in H1650 only Enzastaurin caused a relevant reduction in VEGF expression. The array showed differential phosphorylation of EGFR, GSK3β, EphA1 and MK14. In conclusion, Enzastaurin is a protein kinase Cβ inhibitor, working on several cellular signaling pathways that are involved in proliferation, apoptosis and angiogenesis. These features make it a good compound for combination therapy. In the present study the combination of Enzastaurin and erlotinib gives synergistic results, warranting further investigation.

  • pharmacological aspects of the Enzastaurin pemetrexed combination in non small cell lung cancer nsclc
    Current Drug Targets, 2010
    Co-Authors: Elisa Giovannetti, Giuseppe Giaccone, Richard J Honeywell, Axel R Hanauske, Christina Tekle, Bart C Kuenen, J Sigmond, Godefridus J Peters
    Abstract:

    Conventional regimens have limited impact against NSCLC. Current research is focusing on multiple pathways as potential targets, and this review describes pharmacological aspects underlying the combination of the PKCβ-inhibitor Enzastaurin with the multitargeted antifolate pemetrexed. Pemetrexed is commonly used, alone or combined with platinum compounds, in NSCLC treatment, and ongoing studies are evaluating its target, thymidylate synthase (TS), as predictor of drug activity. Enzastaurin is a biological targeted agent actively being investigated against different tumors as single agent or in combination. All the downstream events following PKCβ inhibition by Enzastaurin are not completely known, and assays to evaluate possible biomarkers, such as expression of PKC, VEGF and GSK3β, in tissues and/or in blood samples, are being developed. Enzastaurin-pemetrexed combination was synergistic in preclinical models, including NSCLC cells, where Enzastaurin reduced phosphoCdc25C, resulting in G2/M-checkpoint abrogation, and Akt and GSK3β phosphorylation, favoring apoptosis induction in pemetrexed-damaged cells. Enzastaurin also significantly reduced VEGF secretion and pemetrexed-induced upregulation of TS expression, possibly via E2F-1 reduction, while the combination decreased TS activity. Similarly, the accumulation of deoxyuridine (a marker of TS inhibition) and the reduction of GSK3β phosphorylation were detectable in clinical samples from a phase-Ib trial of pemetrexed-Enzastaurin combination. In conclusion, the favorable toxicity profile and the multiple effects of Enzastaurin on signaling pathways involved in cell cycle control, apoptosis and angiogenesis, as well as on proteins involved in pemetrexed activity, provide experimental basis for future studies on Enzastaurin-pemetrexed combination and their possible pharmacodynamic markers in NSCLC patients.

  • molecular pathways involved in the synergistic interaction of the pkcβ inhibitor Enzastaurin with the antifolate pemetrexed in non small cell lung cancer cells
    British Journal of Cancer, 2008
    Co-Authors: Christina Tekle, Jeremy R Graff, Elisa Giovannetti, J Sigmond, Kees Smid, Godefridus J Peters
    Abstract:

    Conventional regimens have limited impact against non-small cell lung cancer (NSCLC). Current research is focusing on multiple pathways as potential targets, and this study investigated molecular mechanisms underlying the combination of the PKCβ inhibitor Enzastaurin with the multitargeted antifolate pemetrexed in the NSCLC cells SW1573 and A549. Pharmacologic interaction was studied using the combination-index method, while cell cycle, apoptosis induction, VEGF secretion and ERK1/2 and Akt phosphorylation were studied by flow cytometry and ELISAs. Reverse transcription–PCR, western blot and activity assays were performed to assess whether Enzastaurin influenced thymidylate synthase (TS) and the expression of multiple targets involved in cancer signaling and cell cycle distribution. Enzastaurin-pemetrexed combination was highly synergistic and significantly increased apoptosis. Enzastaurin reduced both phosphoCdc25C, resulting in G2/M checkpoint abrogation and apoptosis induction in pemetrexed-damaged cells, and GSK3β and Akt phosphorylation, which was additionally reduced by drug combination (−58% in A549). Enzastaurin also significantly reduced pemetrexed-induced upregulation of TS expression, possibly through E2F-1 reduction, whereas the combination decreased TS in situ activity (>50% in both cell lines) and VEGF secretion. The effects of Enzastaurin on signaling pathways involved in cell cycle control, apoptosis and angiogenesis, as well as on the expression of genes involved in pemetrexed activity provide a strong experimental basis to their evaluation as pharmacodynamic markers in clinical trials of Enzastaurin-pemetrexed combination in NSCLC patients.

Steven T Rosen - One of the best experts on this subject based on the ideXlab platform.

  • Inhibition of Glycogen Synthase Kinase 3 (GSK3) Increases the Cytotoxicity of
    2016
    Co-Authors: Mark Rovedo, Nancy L Krett, Steven T Rosen
    Abstract:

    Cutaneous T cell lymphomas (CTCL) represent a spectrum of several distinct non-Hodgkin's lymphomas that are characterized by an invasion of the skin by malignant, clonal lymphocytes. Our lab has previously demonstrated that the Protein Kinase C (PKC) β inhibitor Enzastaurin increases apoptosis in malignant lymphocytes of CTCL. These results directly led to a clinical trial for Enzastaurin in CTCL where it was well tolerated and showed modest activity. To ascertain a means of improving the efficacy of Enzastaurin, we investigated complimentary signaling pathways and identified Glycogen Synthase Kinase 3 (GSK3) as important in survival signaling in CTCL. Enzastaurin combined with GSK3 inhibitors demonstrated anenhancement of cytotoxicity. Treatment with a combination of Enzastaurin and the GSK3 inhibitor AR-A014418 resulted in up-regulation of β catenin total protein and β catenin-mediated transcription. Inhibition of β catenin-mediated transcription or shRNA knockdown of β catenin decreased the cytotoxic effects of Enzastaurin plus AR-A014418. In addition, treatment with Enzastaurin and AR-A014418 decreased the mRNA levels and surface expression of CD44. shRNA knockdown of β catenin also restored CD44 surface expression. Our observations provide a rationale for the combined targeting of PKC and GSK3 signaling pathways in CTCL to enhance the therapeutic outcome

  • inhibition of glycogen synthase kinase 3 increases the cytotoxicity of Enzastaurin
    Journal of Investigative Dermatology, 2011
    Co-Authors: Mark Rovedo, Nancy L Krett, Steven T Rosen
    Abstract:

    Cutaneous T-cell lymphomas (CTCL) represent a spectrum of several distinct non-Hodgkin's lymphomas that are characterized by an invasion of the skin by malignant, clonal lymphocytes. Our laboratory has previously demonstrated that the protein kinase C (PKC) β inhibitor Enzastaurin increases apoptosis in malignant lymphocytes of CTCL. These results directly led to a clinical trial for Enzastaurin in CTCL in which it was well tolerated and showed modest activity. To ascertain a means of improving the efficacy of Enzastaurin, we investigated complementary signaling pathways and identified glycogen synthase kinase-3 (GSK3) as important in survival signaling in CTCL. Enzastaurin combined with GSK3 inhibitors demonstrated an enhancement of cytotoxicity. Treatment with a combination of Enzastaurin and the GSK3 inhibitor AR-A014418 resulted in upregulation of β-catenin total protein and β-catenin-mediated transcription. Inhibition of β-catenin-mediated transcription or small hairpin RNA (shRNA) knockdown of β-catenin decreased the cytotoxic effects of Enzastaurin plus AR-A014418. In addition, treatment with Enzastaurin and AR-A014418 decreased the mRNA levels and surface expression of CD44. shRNA knockdown of β-catenin also restored CD44 surface expression. Our observations provide a rationale for the combined targeting of PKC and GSK3 signaling pathways in CTCL to enhance the therapeutic outcome.

  • Enzastaurin ly317615 a protein kinase cβ inhibitor inhibits the akt pathway and induces apoptosis in multiple myeloma cell lines
    Molecular Cancer Therapeutics, 2006
    Co-Authors: Mujahid A Rizvi, Kulsoom Ghias, Katharine M Davies, Frank Weinberg, Hidayatullah G Munshi, Nancy L Krett, Steven T Rosen
    Abstract:

    Enzastaurin (LY317615), an acyclic bisindolylmaleimide, is an oral inhibitor of the protein kinase Cbeta isozyme. The objective of this study was to assess the efficacy of Enzastaurin in inducing apoptosis in multiple myeloma (MM) cell lines and to investigate possible mechanisms of apoptosis. Cell proliferation assays were done on a variety of MM cell lines with unique characteristics (dexamethasone sensitive, dexamethasone resistant, chemotherapy sensitive, and melphalan resistant). The dexamethasone-sensitive MM.1S cell line was used to further assess the effect of Enzastaurin in the presence of dexamethasone, insulin-like growth factor-I (IGF-I), interleukin-6, and the pan-specific caspase inhibitor ZVAD-fmk. Enzastaurin increased cell death in all cell lines at clinically significant low micromolar concentrations (1-3 micromol/L) after 72 hours of treatment. Dexamethasone and Enzastaurin were shown to have an additive effect on MM.1S cell death. Although IGF-I blocked the effect of 1 micromol/L Enzastaurin, IGF-I did not abrogate cell death induced with 3 mumol/L Enzastaurin. Moreover, Enzastaurin-induced cell death was not affected by interleukin-6 or ZVAD-fmk. GSK3beta phosphorylation, a reliable pharmacodynamic marker for Enzastaurin activity, and AKT phosphorylation were both decreased with Enzastaurin treatment. These data indicate that Enzastaurin induces apoptosis in MM cell lines in a caspase-independent manner and that Enzastaurin exerts its antimyeloma effect by inhibiting signaling through the AKT pathway.

  • the selective protein kinase c β inhibitor Enzastaurin induces apoptosis in cutaneous t cell lymphoma cell lines through the akt pathway
    Journal of Investigative Dermatology, 2006
    Co-Authors: Christiane Querfeld, Mujahid A Rizvi, Nancy L Krett, Timothy M Kuzel, Joan Guitart, Alfred W Rademaker, Simran S Sabharwal, Steven T Rosen
    Abstract:

    Enzastaurin displays pro-apoptotic properties against a spectrum of malignancies and is currently being investigated in clinical trials. We have investigated the effects of Enzastaurin on the viability of the cutaneous T-cell lymphoma cell lines HuT-78 and HH by using 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, cell cycle analysis, propidium iodide and annexin-V staining, and caspase-3-mediated proteolytic activation. Enzastaurin-treatment decreased cell viability, increased annexin V-FITC-positive cells, and increased the proportion of sub-G 1 populations in both cell lines that was not reversed by the T-cell growth stimulating cytokines IL-2, IL-7, IL-15. Enzastaurin-induced cell death involved caspase-3-activated cleavage of poly(ADP-ribose) polymerase that was inhibited by the pan-caspase inhibitor ZVAD-fmk, whereas the increase in sub-G 1 population was only partially inhibited by ZVAD-fmk. Furthermore, Enzastaurin downregulated AKT activity and its downstream effectors GSK3 β and ribosomal protein S6. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been implicated in the growth and survival of hematologic malignancies and inhibition of this pathway is considered as a therapeutic target. Protein kinase C activation contributes to PI3K/AKT activation, but it is unknown how Enzastaurin may interfere with signaling through this pathway. These results demonstrate that Enzastaurin, at clinically achievable concentrations, induces apoptosis and affects AKT signaling, and provide a rationale for further in vivo studies addressing the therapeutic efficacy in cutaneous T-cell lymphoma patients.