Tandutinib (MLN518), a Potent FLT3 Inhibitor, Synergizes with Cytarabine and/or Daunorubicin in a Sequence-Independent Manner.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1374-1374 ◽  
Author(s):  
Marcus M. Schittenhelm ◽  
Kevin W. Yee ◽  
Kerstin M. Kampa ◽  
Michael C. Heinrich
Keyword(s):  
Combination Therapy ◽  
Synergistic Effect ◽  
Cell Lines ◽  
Induction Chemotherapy ◽  
Combined Treatment ◽  
Single Agent ◽  
Cytotoxic Agents ◽  
Comparable Efficacy ◽  
Flt3 Inhibitor

Abstract FLT3 kinase inhibitors display promising pre-clinical efficacy in a variety of in vitro and animal models of FLT3-ITD+ AML. Tandutinib is a 4-piprazinylquinazoline compound that is a potent inhibitor of type III RTKs with a cellular IC50 of ~200 nM for FLT3. In a phase 2 study, Tandutinib demonstrated anti-leukemic activity in approximately half of the evaluable patients, although there were no partial or complete remissions. Therefore, optimal use of like Tandutinib will likely require combination therapy with standard cytotoxic agents such as cytarabine (Cy) and an anthracycline (e.g. daunorubicin, Dn). Notably, single agent Tandutinib has not been associated with myelosuppression, mucositis or cardiac toxicity--the dose limiting toxicities of AML chemotherapy. To determine the feasibility of combining Tandutinib and chemotherapy, we tested Tandutinib in combination with Cy and/or Dn. For our experiments, we utilized three cell lines containing FLT3 ITD mutations: a BaF3 cell line transduced with an ITD mutant FLT3 as well as MV 4–11 and MOLM 14 cell lines which have naturally occurring FLT3 ITD mutations. Data was analyzed using the statistical methods of Chou and Talalay to calculate combination indices (CI) for drug mixtures performed in a fixed dilution pattern. In all cell lines, calculated combination indices for inhibition of cellular proliferation and induction of apoptosis were much less than one, indicating a synergistic effect of combining Tandutinib with Cy or Dn. In addition, the combination of Tandutinib with Cy and Dn was also markedly synergistic. These results were confirmed using primary AML blasts (FLT3 ITD+). All of the above studies were performed using simultaneous treatment with Tandutinib and Cy and/or Dn. Previous in vitro studies utilizing a structurally unrelated FLT3 inhibitor, Lestaurtinib (CEP-701), demonstrated the potential importance of treatment sequencing for optimal killing of AML cells. Notably, treatment with Lestaurtinib with or following chemotherapy was found to be synergistic, whereas treatment with Lestaurtinib followed by chemotherapy was generally antagonistic. Therefore, we next determined whether sequencing of Tandutinib and chemotherapy had any effect on the efficacy of combination therapy. For these experiments, we tested two different sequencing regimens: monotherapy treatment with Tandutinib for 24 hours with the addition of Cy or Dn for an additional 48 hours; ormonotherapy with Cy or Dn for 24 hours with the addition of Tandutinib for an additional 48 hours. Both regimens produced a synergistic effect and had comparable efficacy. Therefore, unlike Lestaurtinib, the synergistic effect of Tandutinib and Cy/Dn appears to be independent of the sequence of drug administration. These data suggest that addition of Tandutinib to agents used in induction chemotherapy for AML could result in enhanced antileukemic effects. Our synergy experiments also suggest that combined use of Tandutinib and chemotherapy may allow dose reduction of chemotherapy (with resultant decreased side effects) without loss of antileukemic activity. Such a combined treatment approach may be particularly desirable for elderly AML patients who often have poor tolerance of standard AML chemotherapy regimens. Currently, the combination of Tandutinib + standard induction chemotherapy is being tested in a phase I/II study for treatment of newly diagnosed AML.

scholarly journals Radiosensitisation of Hepatocellular Carcinoma Cells by Vandetanib

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1878 ◽  
Author(s):  
Sami Znati ◽  
Rebecca Carter ◽  
Marcos Vasquez ◽  
Adam Westhorpe ◽  
Hassan Shahbakhti ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Combination Therapy ◽  
Cell Lines ◽  
Radiation Treatment ◽  
Combined Treatment ◽  
New Combination ◽  
Migration And Invasion ◽  
Syngeneic Mouse Model

Hepatocellular Carcinoma (HCC) is increasing in incidence worldwide and requires new approaches to therapy. The combination of anti-angiogenic drug therapy and radiotherapy is one promising new approach. The anti-angiogenic drug vandetanib is a tyrosine kinase inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2) and RET proto-oncogene with radio-enhancement potential. To explore the benefit of combined vandetanib and radiotherapy treatment for HCC, we studied outcomes following combined treatment in pre-clinical models. Methods: Vandetanib and radiation treatment were combined in HCC cell lines grown in vitro and in vivo. In addition to 2D migration and clonogenic assays, the combination was studied in 3D spheroids and a syngeneic mouse model of HCC. Results: Vandetanib IC 50 s were measured in 20 cell lines and the drug was found to significantly enhance radiation cell kill and to inhibit both cell migration and invasion in vitro. In vivo, combination therapy significantly reduced cancer growth and improved overall survival, an effect that persisted for the duration of vandetanib treatment. Conclusion: In 2D and 3D studies in vitro and in a syngeneic model in vivo, the combination of vandetanib plus radiotherapy was more efficacious than either treatment alone. This new combination therapy for HCC merits evaluation in clinical trials.

Marked synergism of cytotoxic agents with either a prenylation inhibitor or M-TOR inhibitor in acute leukemia cell lines: Potential clinical implications

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 13103-13103
Author(s):  
D. R. Budman ◽  
A. Calabro
Keyword(s):  
Acute Leukemia ◽  
Cell Lines ◽  
Single Agent ◽  
Leukemia Cell ◽  
Cytotoxic Agents ◽  
Human Leukemia ◽  
Effect Analysis ◽  
Leukemia Cell Lines ◽  
Classical Combination

13103 Background: The most combinations of anticancer drugs are based upon empiricism. The potential permutations of drugs overwhelm the clinical trials system. Acute leukemia is sensitive to a variety of agents but relapses are common. Targeted agents are attractive new venues of therapy both as single agents and in combination with older agents. Isobologram median effect analysis allows up to three agents to be studied together in vitro to identify interesting combinations. We evaluated a commercially available statin, fluvastatin, to block prenylation which affects a variety of pathways, rapamycin and its experimental analogue RAD001 as M-TOR inhibitors to block downstream of the AKT pathway, and cytotoxic agents. Methods: The human leukemia cell lines AML-193 and KG-1 were obtained from ATTC (Rockville, MD), fluvastatin and RAD001 from Novartis Pharma, and the other agents from Sigma-Aldrich (St. Louis, MO). The IC50 of the single agent was determined by a 72 hr incubation of log growth cells using a MTT assay and the EZ-ED50 program (Perrella Scientific, Conyers, CA). The dosages of all agents were at clinically achievable concentrations. All reported values were the means of at least 3 experiments with each study using 4 wells per point. For isobologram analysis, a minimum of 8 concentrations of drug mixtures were studied above and below the IC50. Median effect CI values less than 1 are synergistic. Results: Doublets of fluvastatin with Ara-C (0.7), daunomycin (0.4), idarubicin (0.7), RAD001 (0.5), or rapamycin (0.3) demonstrated synergy. Doublets of RAD001 with Ara-C (0.3), daunomycin (0.7), or idarubicin (0.5) demonstrated synergy. Triplets of RAD001/daunorubicin/Ara-C, RAD001/daunomycin/fluvastatin, and RAD001/Ara-C/idarubicin all demonstrated marked synergy in both cell lines. Conclusion: A new potential non classical combination for further investigation is RAD001 or rapamycin with an inhibitor of prenylation such as fluvastatin. Additional potential combinations include cytotoxics with either fluvastatin or RAD001, and triplet combinations. No significant financial relationships to disclose.

scholarly journals Combination Therapy of Bcl-2/X L dual Inhibitor AZD0466 with Acalabrutinib to Overcome Therapeutic Resistance in Aggressive R/R Mantle Cell Lymphoma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1867-1867
Author(s):  
Yijing Li ◽  
Yang Liu ◽  
Yuxuan Che ◽  
Joseph McIntosh ◽  
Alexa A Jordan ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Research Funding ◽  
Single Agent ◽  
Dual Inhibitor ◽  
Car T ◽  
Mantle Cell

Abstract Introduction As a rare form of non-Hodgkin's lymphoma, mantle cell lymphoma (MCL) is an aggressive subtype. This is largely due to frequent relapses after therapies including paradigm shifting therapies BTK inhibitors (BTKi), such as ibrutinib and acalabrutinib, and Bcl-2 inhibitor (Bcl-2i) venetoclax after long-term treatment in the clinic. Dysregulation of Bcl-2 and Bcl-X L, contributes to therapeutic resistance in MCL. AZD0466 is a novel and highly potent Bcl-2/X L dual inhibitor with active moiety AZD4320. Our preliminary data showed AZD4320 is potent in inhibiting cell viability of MCL cells (IC 50 = 1.6-78 nM). In this study, we assessed the combination efficacy of AZD4320/AZD0466 and acalabrutinib on preclinical MCL models. Methods Cell viability assay was performed to assess the in vitro efficacy of AZD4320 and acalabrutinib alone or in combination in a panel of ibrutinib/venetoclax-sensitive and -resistant MCL cell lines. Cell apoptosis assay was also performed to determine if AZD4320 and acalabrutinib enhanced cell death by cell apoptosis in MCL cell lines. Protein expression profiles of a panel of pro- and anti-apoptotic proteins and other relevant proteins were detected by immunoblotting. Since AZD4320 is limited in preclinical model due to physicochemical properties and dose limiting cardiovascular toxicity, AZD0466, the drug-dendrimer conjugate of AZD4320, was used for in vivo experiment. In vivo efficacy of AZD0466 (34 mg/kg, weekly, iv) and acalabrutinib (20 mg/kg, BID, oral) alone or in combination was evaluated using a Mino-venetoclax-R (Mino-R) cell xenograft model and a PDX model derived from an ibrutinib-CAR-T dual-resistant MCL patient. Results AZD4320 in combo with acalabrutinib inhibited cell proliferation synergistically in both ibrutinib/venetoclax-sensitive and -resistant cell lines (combination index = 0.17-0.93). Compared to vehicle or either single agent, the combination enhanced cell apoptosis by increasing pro-apoptotic markers cleaved caspase 3 and cleaved PARP. In the xenograft mouse model derived from venetoclax-resistant Mino-R cells, co-treatment of AZD0466 and acalabrutinib decreased tumor size significantly compared to vehicle (n = 5, p < 0.0001) or either single agent (n = 5, p = 0.0118 and 0.0070, respectively). Furthermore, in the PDX mouse model derived from a patient relapsed subsequently from ibrutinib and CAR T therapy, the combination of AZD0466 and acalabrutinib inhibited tumor growth compared to vehicle or either single agent. Acalabrutinib or AZD0466 improved survival compared with vehicle by 14 days or 32 days, respectively. Compared to Acalabrutinib or AZD0466, the combination therapy extended survival by 25 days and 7 days, respectively. All mice tolerated the treatment dose without any weight loss compared to the vehicle or either single agent group. Conclusion Compared to AZD4320/AZD0466 and acalabrutinib, combination therapy demonstrated anti-MCL synergy both in vitro and in vivo. These findings suggest that targeting Bcl-2/X L and BTK is promising to overcome multiple acquired resistance phenotypes, including CD19 CAR T-cell therapy. Disclosures Andersen: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Cidado: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Wang: DTRM Biopharma (Cayman) Limited: Consultancy; BeiGene: Consultancy, Honoraria, Research Funding; Physicians Education Resources (PER): Honoraria; Anticancer Association: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; CAHON: Honoraria; The First Afflicted Hospital of Zhejiang University: Honoraria; Epizyme: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria, Research Funding; BGICS: Honoraria; Imedex: Honoraria; Clinical Care Options: Honoraria; Celgene: Research Funding; Genentech: Consultancy; Loxo Oncology: Consultancy, Research Funding; InnoCare: Consultancy, Research Funding; Molecular Templates: Research Funding; Lilly: Research Funding; VelosBio: Consultancy, Research Funding; BioInvent: Research Funding; Oncternal: Consultancy, Research Funding; OMI: Honoraria; Newbridge Pharmaceuticals: Honoraria; Scripps: Honoraria; Hebei Cancer Prevention Federation: Honoraria; Chinese Medical Association: Honoraria; Pharmacyclics: Consultancy, Research Funding; Juno: Consultancy, Research Funding; CStone: Consultancy; Bayer Healthcare: Consultancy; Miltenyi Biomedicine GmbH: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria, Research Funding; Acerta Pharma: Consultancy, Honoraria, Research Funding; Dava Oncology: Honoraria; Moffit Cancer Center: Honoraria; Mumbai Hematology Group: Honoraria.

Combination of Akt/PKB Inhibition (Perifosine) and Farnesyl Transferase Inhibition (Tipifarnib) Results in Increased Cell Death in Myeloma Cells Lines.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1568-1568 ◽  
Author(s):  
Rajni Sinha ◽  
Ebenezer David ◽  
Emily Zeilter ◽  
Claire Torre ◽  
Jonathan L. Kaufman ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cell Death ◽  
Combination Therapy ◽  
Cell Line ◽  
Cell Lines ◽  
Single Agent ◽  
Myeloma Cell ◽  
Myeloma Cell Line

Abstract Introduction Multiple myeloma is a clonal plasma cell malignancy characterized by proliferation and accumulation of plasma cells in the bone marrow. Most patients are incurable with the current treatment modalities. Clearly novel agents are needed to improve the outcome for patients with myeloma. We have previously shown that the combination of bortezomib and tipifarnib results in synergistic myeloma cell death. This increase in apoptosis is associated with down regulation of phosphorylated AKT, a potent anti-apoptotic signaling molecule. Therefore, agents that target AKT represent ideal compounds for further study in myeloma. Perifosine is a novel, oral bioavailable alkylphospholipid. Perifosine has displayed apoptotic and antipropliferative activity in vitro and in vivo in several human cancer models including leukemia. Perifosine exerts its actions by interfering with key intracellular pathways including AKT, MAPK, JNK, p21waf1. Our hypothesis is that targeting AKT via multiple upstream pathways will result in increased myeloma cell apoptosis. Therefore, we assessed the effects of single agent perifosine with and without tipifarnib on multiple myeloma cell lines. Method The myeloma cell line RPMI8226 was used. Cell viability and proliferation were assessed using MTT assays. Cells were incubated with increasing concentrations of both agents alone and in combination. Cell proliferation was assayed at 24, 48 and 72 hours. Western blots were then carried out to evaluate the effects of the intracellular protein PDK1, one of the critical signaling molecules that phosphorylates and activates AKT. Results As we and others have previously shown, tipifarnib at concentrations that can be achieved clinically is associated with minimal cytotoxicity. At 5 μM, tipifarnib decrease proliferation by only 20%. In contrast, there is a potent dose response effect of single agent perifosine (Fig. 1). These results were apparent as early as 24 hours. When tipifarnib at 5 μM is used in combination with a subtherapeutic dose of perifosine (2 μM), there is a marked decrease in cell proliferation (Fig. 2). In addition, combination therapy resulted in a reduction in the phosphorylated form of PDK1, a critical finding that was not seen with either drug alone. Conclusion Combination therapy with tipifarnib and perifosine results in less cell proliferation compared to either agent used alone in the RPMI8226 myeloma cell line. The dosages employed in these in-vitro studies are lower than those used in previously published data and are clinically achievable. Studies targeting other cell lines including MM.1R, MM.1S, and U266 are in progress. Analysis of AKT, Caspase 3, 8 and 9 are being explored to help delineate the mechanism of this novel combination. The goal is to develop further effective treatment options for patients with myeloma. Figure 1 Figure 1. Figure 2 Figure 2.

scholarly journals A3 Adenosine and P2X7 Purinergic Receptors as New Targets for an Innovative Pharmacological Therapy of Malignant Pleural Mesothelioma

2021 ◽  
Vol 11 ◽  
Author(s):  
Fabrizio Vincenzi ◽  
John Charles Rotondo ◽  
Silvia Pasquini ◽  
Francesco Di Virgilio ◽  
Katia Varani ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Synergistic Effect ◽  
Cell Lines ◽  
Malignant Pleural Mesothelioma ◽  
Combined Therapy ◽  
Combined Treatment ◽  
Pharmacological Therapy ◽  
Pleural Mesothelioma ◽  
P2x7 Receptors

Human malignant pleural mesothelioma (MPM) is a rare, but aggressive tumor of the serosal cavities whose 5-year survival rate is 15%. At present, there are no effective therapies for MPM. Although recent findings suggest that A3 adenosine (A3AR) and P2X7 (P2X7R) receptors can be employed as antitumoral pharmacological targets in MPM, their potential role in a combined therapy is currently unknown. The A3AR agonist Cl-IB-MECA and the P2X7 receptor antagonist AZ10606120, as a single compound or in combination, were investigated in vitro for their anti-tumor activities. Assays were carried out in MPM cell lines IST-Mes2 and MPP89 and in primary human normal mesothelial cells (HMCs), as control. Single treatment with Cl-IB-MECA reduced cell proliferation and favored a pro-apoptotic effect in both MPP89 and IST-Mes2 cell lines, whereas AZ10606120 inhibited cell proliferation and induced apoptosis in IST-Mes2, only. The combined treatment with Cl-IB-MECA and AZ10606120 reduced cell proliferation and favored apoptosis in MPP89 and IST-Mes2 cell lines, whereas no synergistic effect was detected. These data cumulatively suggest the absence of a synergistic effect in combined targeting of A3 adenosine and P2X7 receptors of MPM cell lines. This study may stimulate further investigations aimed at determining new combinations of antitumor compounds and more effective therapeutic strategies against MPM.

Inhibition Of Wee1 Enhances The Anti-Leukemic Effects Of Antimetabolites In Vitro and In Vivo

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1281-1281
Author(s):  
James B. Ford ◽  
Susan Fosmire ◽  
Annemie van Linden ◽  
Dmitry Baturin ◽  
Christopher C. Porter
Keyword(s):  
Combination Therapy ◽  
Mouse Model ◽  
Acute Leukemia ◽  
Cell Lines ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Single Agent ◽  
Parp Cleavage

Abstract While some patients with acute leukemia are cured, for many subsets of patients current therapeutic strategies are not adequate. Novel therapeutic approaches are needed for patients with higher risk leukemias, including T-ALL and AML. We and others identified Wee1 as a potential target in AML cells using RNAi screening. We have validated chemosensitization to cytarabine by genetic and pharmacologic inhibition of Wee1 in AML cell lines and primary patient samples ex vivo. A Wee1 inhibitor, MK1775, is in clinical development. We sought to further our findings with a wider range of conventional anti-leukemia agents, to determine whether the functionality of p53 influences chemosensitization, and to determine the tolerability and efficacy of MK1775 in combination with cytarabine in a mouse model of leukemia. We have found that MK1775 synergistically inhibits proliferation of the T-ALL Jurkat cell line with several antimetabolite chemotherapeutics including cytarabine, 6-thioguanine, and methotrexate. In contrast, MK1775 does not sensitize Jurkats to doxorubicin or etoposide, suggesting specific sensitization to antimetabolites. The addition of MK1775 enhances the antimetabolite induced apoptosis, as measured by Annexin V/7-AAD staining, and PARP cleavage measured by Western blotting. As expected, the addition of MK1775 enhances DNA damage induced by cytarabine as measured by γH2AX staining and flow cytometry, although preliminary data suggest that this is not the only mechanism of enhanced cell death, as a substantial proportion of cleaved PARP+ cells does not stain for γH2AX. In addition, we have found that AML cell lines with both wild-type and mutated TP53 are sensitive to chemosensitization by Wee1 inhibition. Furthermore, in isogenic models of p53 dysfunction, we have found that the functionality of p53 does not influence chemosensitization. Lastly, in an aggressive mouse model of AML, we observed enhanced disease control and survival in mice treated with MK1775 and ARA-C as compared to ARA-C alone. Hematotoxicity associated with treatment was related to the duration of combination therapy, but was tolerated well with intermittent dosing. Taken together, these data indicate that Wee1 inhibition may enhance the efficacy of several clinically relevant anti-leukemia agents, particularly the antimetabolites, but not topoisomerase inhibitors. Further, they suggest caution about the use of p53 mutation as a biomarker predictive of response to Wee1 inhibition. Moreover, we show that the addition of MK1775 to cytarabine is tolerable and more effective than cytarabine alone in vivo. Ongoing studies are aimed at better understanding the mechanism of combinatorial effect and to determine whether combination therapy is more efficacious than single agent therapy in xenograft models of leukemia. These data provide justification for early phase clinical trials of MK1775 in combination with antimetabolites in patients with high risk acute leukemia. Disclosures: No relevant conflicts of interest to declare.

scholarly journals GSK-3 Inhibition is Cytotoxic in Glioma Stem Cells through Centrosome Destabilization and Enhances the Effect of Radiotherapy in Orthotopic Models

Cancers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 5939
Author(s):  
Anke Brüning-Richardson ◽  
Gary C. Shaw ◽  
Daniel Tams ◽  
Tim Brend ◽  
Hitesh Sanganee ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cytotoxic Effect ◽  
Glycogen Synthase ◽  
Combined Treatment ◽  
Single Agent ◽  
Drug Uptake ◽  
Growth Delay ◽  
Cancer Models ◽  
Established Cell

Background: Previous data on glycogen synthase kinase 3 (GSK-3) inhibition in cancer models support a cytotoxic effect with selectivity for tumor cells compared to normal tissue but the effect of these inhibitors in glioma has not been widely studied. Here, we investigate their potential as cytotoxics in glioma. Methods: We assessed the effect of pharmacologic GSK-3 inhibition on established (U87, U251) and patient-derived (GBM1, GBM4) glioblastoma (GBM) cell lines using cytotoxicity assays as well as undertaking a detailed investigation of the effect on cell cycle, mitosis, and centrosome biology. We also assessed drug uptake and efficacy of GSK-3 inhibition alone and in combination with radiation in xenograft models. Results: Using the selective GSK-3 inhibitor AZD2858, we demonstrated single agent cytotoxicity in two patient-derived glioma cell lines (GBM1, GBM4) and two established cell lines (U251 and U87) with IC50 in the low micromolar range promoting centrosome disruption, failed mitosis, and S-phase arrest. Glioma xenografts exposed to AZD2858 also showed growth delay compared to untreated controls. Combined treatment with radiation increased the cytotoxic effect of clinical radiation doses in vitro and in orthotopic glioma xenografts. Conclusions: These data suggest that GSK-3 inhibition promotes cell death in glioma through disrupting centrosome function and promoting mitotic failure and that AZD2858 is an effective adjuvant to radiation at clinical doses.

Primary glioblastoma cell lines as source for analysis of the relationship between molecular phenotype and in-vitro drug sensitivity.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e13053-e13053
Author(s):  
Carl Friedrich Classen ◽  
Christina S Mullins ◽  
Julia Schubert ◽  
Piek Jürgen ◽  
Michael Linnebacher ◽  
...  
Keyword(s):  
Cell Lines ◽  
Drug Sensitivity ◽  
Combined Treatment ◽  
Single Agent ◽  
Response Analysis ◽  
Pathology Laboratory ◽  
In Vivo Models ◽  
Molecular Features

e13053 Background: Glioblastoma multiforma (GBM) still has a very poor prognosis even with today’s multimodal combination therapy of resection followed by radio-chemotherapy with temozolomide. Both new molecular inhibitors and immunotherapy may represent future therapeutical tools but due to the variability of the molecular composition in individual GBM, they probably depend on better response prediction. Methods: Based on a close cooperation and logistics between surgery, pathology, laboratory researchers and animal care facilities, we established and analysed cell lines of about 30 primary brain tumors, most of them GBM. Tumors and cell lines were characterised by morphology, growth behaviour, numerous extra- and intracellular antigens, and particularly regarding molecular features. Further, tumors were established in a subcutaneous xenograft mouse model, and growth characteristics were described. These in vitro and in vivo models represent an ideal tool for response analysis of single agent or combined treatment in early cell passages in order to predict response. Besides, relevant antigens and possible shifts of antigen-presentation in tumors can be assessed. Numerous analyses using established and new antitumor compounds – e.g. the integrin inhibitor cilengitide – were performed. Results: We found that although the specific integrin expression is individually different in the tumors analysed, cilengitide sensitivity was similar in most. Addition of temozolomide led to additional, yet not over-additive cytotoxicity. In our panel of GBM specimens we found a very heterogenous pattern of molecular alterations, going along with variations of drug sensitivity. Conclusions: This indicates that, in the future field of individualized approaches, such models are required, in order to enable future strategies to predict the efficacy of immunological, small molecular, biological-based, cytotoxic or other therapeutic strategies. The project was supported by the Förderkreis für krebskranke Kinder Rostock e.V., by a Mecklenburg-Vorpommern graduate scholarship, and by a cooperation with Merck-Serono Research and Development (gift of drug).

Relationship of EGFR-independent activation of PI3K in KRAS wild-type colorectal cancers and cetuximab resistance.

2013 ◽  
Vol 31 (4_suppl) ◽  
pp. 385-385 ◽  
Author(s):  
Ryan Bruce Corcoran ◽  
Hiromichi Ebi ◽  
David P. Ryan ◽  
Jeffrey A. Meyerhardt ◽  
Jeffrey A. Engelman
Keyword(s):  
Cell Lines ◽  
Combined Treatment ◽  
Single Agent ◽  
Pi3k Pathway ◽  
Erk Signaling ◽  
Regulatory Subunit ◽  
Pi3k Activation ◽  
Xenograft Models ◽  
Pre Treatment

385 Background: Therapies targeting receptor tyrosine kinases (RTKs) are typically effective only when they lead to simultaneous inhibition of PI3K-AKT and MEK-ERK signaling. Cetuximab is a monoclonal antibody against EGFR that has been approved for treatment of metastatic colorectal cancer (CRC). Studies have suggested that its benefit is restricted to patients with KRAS wildtype (WT) CRC. However, even in KRAS WT CRC, the response rate to single-agent cetuximab is low, and the mechanistic basis for this is not well-understood. Methods: The ability of cetuximab to inhibit PI3K-AKT and MEK-ERK signaling in a panel of KRAS WT CRC cell lines was assessed by immunoblotting. Paired biopsies from CRC patients obtained pre-treatment and after 3 weeks of cetuximab were evaluated by immunohistochemistry and proteomic techniques to assess inhibition of PI3K activity. We preformed immunoprecipitations (IPs) of the regulatory subunit of PI3K from cell lines and primary CRCs to identify RTKs involved in PI3K activation. Cetuximab-based therapeutic combinations were evaluated in KRAS WT CRC cell lines and xenograft models. Results: Cetuximab led to effective inhibition of MEK-ERK signaling (>75% reduction in phospho-ERK), but led to incomplete inhibition of PI3K-AKT signaling (0-50% reduction in phospho-AKT) in all KRAS WT CRC cell lines tested. Analysis of paired biopsies from patients with KRAS WT CRC obtained pre-treatment and after 3 weeks of cetuximab demonstrated that the PI3K pathway remained active in many patients, despite cetuximab therapy. PI3K regulatory subunit IPs from cell lines and primary CRCs revealed multiple RTK inputs to PI3K, most notably from IGFIR. Combined treatment with cetuximab and an IGFIR inhibitor or a PI3K inhibitor led to improved efficacy in vitro and to tumor regressions in KRAS WT CRC xenograft models. Conclusions: Cetuximab fails to inhibit PI3K signaling in some KRAS WT CRCs. Additional RTKs other than EGFR play a role in PI3K activation in these cancers, which may contribute to cetuximab resistance. Combining cetuximab with targeted therapies directed against the PI3K pathway may lead to improved efficacy in KRAS WT CRC, and should be evaluated in future clinical trials.

EXTH-05. TUMOR TREATING FIELDS IN COMBINATION WITH THE TERT-INHIBITOR ERIBULIN HAVE SYNERGISTIC ANTIPROLIFERATIVE EFFECTS ON HUMAN GLIOBLASTOMA CELLS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi164-vi164
Author(s):  
Marco Stein ◽  
Piet Beusker ◽  
Hanna Goett ◽  
Malgorzata Kolodziej ◽  
Eberhard Uhl
Keyword(s):  
Cell Death ◽  
Combination Therapy ◽  
Synergistic Effect ◽  
Cell Lines ◽  
Combined Treatment ◽  
Antiproliferative Effects ◽  
Tumor Treating Fields ◽  
Cell Counts ◽  
Established Cell ◽  
Human Gbm

Abstract OBJECTIVE Combination therapy, a treatment modality that combines two or more therapeutic agents, is a cornerstone of cancer therapy. The optimal combination therapy for Tumor Treating Fields (TTFields) in glioblastoma (GBM) treatment is unknown. The aim of our study was to analyze, the effects of the TERT-inhibitor eribulin in combination with TTFields on human GBM cells. METHODS Human GBM cells of the established cell lines U87, A172 and U251, and two patient-derived cell lines, were treated with eribulin monotherapy, TTFields monotherapy, or both modalities together. After 72 hours of therapy, cell counts were measured and clonogenic assays were performed. Annexin staining and fluorescence-activated cell scanning (FACS) was used to analyze cell death. RESULTS Overall surviving fractions were 39.8±11.0% for eribulin monotherapy, 32.2±23.9% for TTFields monotherapy, and 10.9±9.9% for the combined treatment. Mean observed annexin positive fractions were 11.2±8.2% (control), 28.6±9.7% (eribulin), 34.8±8.1% (TTFields), and 78.1±13.5% (combination), respectively. The mean clonogenic fractions over all cell lines were 25.9±7.8% for eribulin and 46.4±12.9% for TTFields. For the combination therapy, a synergistic effect with a decreased mean of 3.6% clonogenic fractions was observed. CONCLUSION Eribulin increases cell death and reduces clonogenicity our experiments. Additionally, a synergistic effect of the combined treatment of TTFields and eribulin synergistic was observed. Eribulin in combination with TTFields could be a new effective therapy for GBM.

Sign in / Sign up

Export Citation Format

Share Document