Novel Targeting Of Phospho-Marcks Overcomes Drug Resistance and Induces Anti-Tumor Activity In Preclinical Models Of Multiple Myeloma

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 282-282 ◽  
Author(s):  
Yijun Yang ◽  
Manujendra N Saha ◽  
Yan Chen ◽  
Lugui Qiu ◽  
Donna E Reece ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drug Resistance ◽  
Cell Lines ◽  
Research Funding ◽  
Resistant Cell ◽  
Drug Resistant ◽  
Sensitive Cell ◽  
Bortezomib Treatment ◽  
Cell Cycle Pathway ◽  
Rpmi 8226

Abstract Multiple myeloma (MM) remains incurable due to the development of a drug-resistant phenotype after prolonged therapy. Myristoylated alanine-rich C-kinase substrate (MARCKS) is a protein kinase C (PKC) substrate that plays an important role in cell adhesion, spreading and invasion. Our previous studies found that overexpression of phospho-MARCKS (pMARCKS) was detected in developed drug resistant MM cell lines (RPMI-8226 R5, MM.1R) relative to their parental drug sensitive cell lines (RPMI-8226S, MM.1S). We hypothesized that pMARCKS is involved in chemo- and novel drug resistance in MM. To further evaluate the drug resistance, we exposed both RPMI-8226 R5 and MM.1R cell lines to varying dosages of bortezomib, dexamethasone, doxorubicin, and lenalidomide. By MTT assay, both resistant cell lines were found to have significantly higher viability to all 4 drugs compared to their respective non-resistant lines. In addition, Western blot analysis showed increased pMARCKS expressions in all 3 bortezomib resistant cell lines 8226.BR, OPM2.BR, and ANBL-6.BR as compared to their respective bortezomib sensitive cell lines. We next acquired MM patient samples collected at diagnosis and at relapse after bortezomib treatment, and investigated their pMARCKS expression with immunoblotting analyses. The patient samples collected from relapse after bortezomib treatment had higher pMARCKS expression than those collected at diagnosis. Furthermore, we studied additional 3 primary MM patient samples with high pMARCKS expressions and 3 with low expressions for their vaibility after a 36 hour bortezomib treatment, and found that the samples with high pMARCKS expressions were more resistant to bortezomib than those with low pMARCKS expressions (mean IC50 of 7.1 nM and mean IC50 of 4.8 nM, respectively; p = 0.042). Importantly, combination of a low dosage of bortezomib (5.0 nM) with either 2.5 uM or 5.0 uM of enzastaurin (an inhibitor of phospho-PKC), displayed a synergistic cytotoxicity on myeloma cells with high pMARCKS expressions. To further elucidate the role of pMARCKS in drug resistance, we knocked down pMARCKS expression by transfecting siMARCKS into 8226 R5 and MM.1R cells. Following the knockdown, both cell lines had significantly lower viability after treatment with either bortezomib, dexamethasone, doxorubicin, or lenolidomide, in comparison to empty vector controls. FACS analysis and annexin V assay of the knockdown cells and the control cells from both cell lines showed significantly induction of G1/S cell cycle arrest and apoptosis in the knockdown cells. The immunoprecipitation (IP) and chromatin immunoprecipitation (ChIP) DNA-qPCR analysis further demonstrated that pMARCKS regulates SKP2 expression through binding with E2F1, mediating SKP2/p27Kip1 cell cycle pathway. Finally, we investigated the effect of inhibition of pMARCKS in a 8226 R5 xenograft model of SCID mice. Mice injected with shMARCKS-transfected 8226 R5 cells and received bortezomib showed significant retardation of tumor growth and prolonged survival compared to the control groups. Taken together, our data indicate that pMARCKS is constitutively activated in resistant and relapsed MM cells and contributes to drug resistance by regulating E2F1 mediated SKP2/p27Kip1 cell cycle pathway, thus providing a preclinical rationale for targeting pMARCKS as a promising approach in patients with refractory/relapsed MM. Disclosures: Reece: BMS: Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Millennium: Research Funding; Novartis: Honoraria; Onyx: Honoraria.

scholarly journals Activity of the Phosphatidylinositol 3-Kinase (PI3K) Inhibitor, Copanlisib, As a Single Agent and in Combination with Carfilzomib in Multiple Myeloma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5665-5665
Author(s):  
Sarah M Larson ◽  
Mao Yu Peng ◽  
Andrae Vandross ◽  
Monica Mead ◽  
Zoe Fuchs ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Cell Lines ◽  
Research Funding ◽  
Single Agent ◽  
Myeloma Cell ◽  
Resistant Cell ◽  
Cell Senescence ◽  
Sensitive Cell ◽  
Multiple Myeloma Cell

Abstract Background: The PI3K pathway signals for cell proliferation and survival in many malignancies including multiple myeloma. Copanlisib (BAY 80-6946) is a pan-class I PI3K inhibitor with preferential activity of the alpha and delta isoforms, of which the alpha isoform has particular importance in multiple myeloma. Here we demonstrate the pharmacological activity of copanlisib in multiple myeloma as a single agent and in combination with carfilzomib biomarker exploratory evaluation using phosphorylation of the S6 ribosomal protein (p-S6). Methods: 21 multiple myeloma cell lines were initially screened. Using an IC50 cut off of 100nM, 3 sensitive: NCI-H929, MM.1S, L-363 and 3 resistant: AMO-1, JJN3, COLO-677 were selected for further analysis. Apoptosis and cell senescence assays were done with each agent (copanlisib at 50nM and 100nM at 72 hours; carfilzomib at 2 nM and 20nM at 96 hours). Cell cycle analysis and induction of apoptosis were performed by FACS after propidium iodide or Annexin V FITC staining, respectively. Cellular senescencewas determined by measurement of β-galactosidase activity in cells treated for 96 hours. Combination studies utilized excess over highest single agent statistics (EOHSA) to evaluate potentiation. Reverse phase protein array (RPPA) was performed at baseline and post treatment for proteomics analysis with confirmatory western blot at 4 and 24 hours post treatment. Results: Copanlisib induced apoptosis and cell cycle arrest in the sensitive cell lines, but not the resistant cell lines. The cell senescence assays confirmed apoptosis rather than cell senescence as the mechanism of inhibition of proliferation. Pretreatment RPPA analysis demonstrated lower p-S6 levels in the sensitive cells lines compared to the resistant cell lines. Further, treatment with copanlisib resulted in a greater decrease in p-S6 in the sensitive cell lines than in the resistant cell lines, which was validated by western blot. Downstream pathway effects were confirmed by an increase in PDCD4 in the sensitive cell lines. Treatment with copanlisib and carfilzomib showed potentiation by EOHSA statistics and further decrease in p-S6 expression in the sensitive rather than resistant cell lines. Discussion: Copanlisib demonstrated single agent activity in human multiple myeloma cell lines, which is enhanced by the addition of carfilzomib. p-S6 levels may serve to select the most appropriate patient population to study combination of carfilzomib and copanlisib in relapsed/refractory multiple myeloma. With the choices of therapy available to patients with multiple myeloma there is a need for predictive biomarkers in order to better sequence therapies. Disclosures Larson: BMS: Consultancy. Slamon:Novartis: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria; Pfizer: Honoraria, Research Funding; Eli Lilly: Consultancy; Syndax: Research Funding; Bayer: Consultancy.

scholarly journals Correlation of Non-Coding RNA Expression with Response to Proteasome Inhibitors in Multiple Myeloma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3415-3415
Author(s):  
Ehsan Malek ◽  
Tahir Latif ◽  
Anil Goud Jegga ◽  
Sajjeev Jagannathan ◽  
Nikhil Vad ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Lines ◽  
Plasma Cells ◽  
Proteasome Inhibitors ◽  
Resistant Cell ◽  
Drug Resistant ◽  
Patient Response ◽  
Drug Naïve ◽  
Rpmi 8226 ◽  
Resistant Cells

Abstract Background: Multiple myeloma (MM) is a heterogeneous diseaseand there is an increased need for more accurate risk classification methods to improve treatment decision-making because of its high impact on clinical outcomes. Here, we demonstrate evidence to support the prognostic value of non-coding RNAs (ncRNAs) as newly discovered genetic biomarkers of drug-resistant and/or high-risk forms of MM. NcRNAs, e.g., long ncRNAs (lncRNAs) and microRNAs (miRNAs), act as positive or negative regulators of gene expression to control cell proliferation, apoptosis and drug resistance. NcRNAs have been shown to play a role in both solid and hematological tumors. Stratification of MM based upon cytogenetic abnormalities and protein-coding gene signatures does not adequately correlate with the depth and durability of response to novel agents such as bortezomib. Therefore, ncRNAs as new class of molecular effectors may enhance the basic understanding of myelomagenesis and provide better stratification of myeloma subtypes. To investigate the role of ncRNAs in resistance to proteasome inhibitors (PIs), we compared global ncRNA profiling in drug-naïve cells to cells with acquired resistance to the PIs bortezomib, carfilzomib and ixazomib. We hypothesized that ncRNAs commonly deregulated in the 3 resistant cell lines would yield a ncRNA signature and novel therapeutic targets. Experimental Procedures: RPMI 8226 cells resistant to PIs were generated through successive exposure to bortezomib, carfilzomib or ixazomib over a period of 6 months. Total RNA was isolated and genome-wide ncRNA expression profiling was performed using Affymetrix3.0 microarray chips that contained nearly 40,000 miRNA and 13,300 lncRNA probes. NcRNA expression profiles from drug-resistant cells were compared to that of drug- naïve parental cells treated with vehicle alone using the same treatment algorithm. Housekeeping genes were used for log expression normalization. MM patients' bone marrow aspirates were obtained from patients after University of Cincinnati Institutional Review Board approval. Results: Bioinformatic analysis of the ncRNA profiles identified a panel of 87 lncRNAs and ~40 miRNAs that were significantly (>100-fold) deregulated in all three drug-resistant cell lines relative to drug- naïve parental cells. Strikingly, ~90% of the deregulated lncRNAs exhibited a similar expression pattern in all 3 PI-resistant cell lines. Twenty lncRNAs were deregulated > 1000-fold in all 3 resistant cell lines (Figure 1). RPMI 8226 cells carry a chromosomal (14,16) translocation. Interestingly, none of the deregulated lncRNAs detected here localized to chromosome 14 or 16, suggestive of a cytogenetic-independent mechanism of drug resistance. The lncRNA COL4A-2A was upregulated >5,000-fold in resistant cells and displayed extensive sequence complementarity to miRNA-29 that was downregulated in resistant cells. Also, our microarray-based studies have identified ncRNAs deregulated in MM patient tumor samples relative to normal plasma cells from healthy age-matched individuals. A significant number of the deregulated ncRNAs between drug- naïve and drug resistant cells were also deregulated in normal plasma cells relative to myeloma cells. Studies are correlating the ncRNA patterns seen in drug-sensitive and drug-resistant cell lines with ncRNA patterns obtained from malignant plasma cells of patients currently receiving bortezomib-based therapy. Updated results to correlate ncRNA expression with myeloma patient response to bortezomib will be presented.Conclusions: Taken together, we have identified a curated panel of ncRNAs deregulated in common within myeloma cells generated with acquired resistant to three different clinically-relevant proteasome inhibitors. Ongoing studies will correlate ncRNA expression patterns from resistant cells with patterns generated from patients with monoclonal gammopathy of unknown significance (MGUS), Smoldering MM, newly diagnosed MM, refractory disease and plasma cell leukemia. In addition, ncRNA patterns will be generated based upon MM patient response to bortezomib. Further investigation is warranted to shed light on the role of these ncRNAs in the development of MM, to identify their targets and to define their role in drug resistance. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Proteomics as a Functional Tool in Evaluating Bortezomib Treatment and Drug Resistance Mechanism.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1805-1805
Author(s):  
Melissa G Ooi ◽  
Paul Dowling ◽  
Paul Richardson ◽  
Constantine S. Mitsiades ◽  
Martin Clynes ◽  
...  
Keyword(s):  
Cell Lines ◽  
Research Funding ◽  
Mass Spectra ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Resistant Cell ◽  
Sensitive Cell ◽  
Advisory Committees ◽  
Tandem Mass Spectra ◽  
Bortezomib Treatment

Abstract Abstract 1805 Poster Board I-831 Background Multiple Myeloma (MM) is an incurable plasma cell disorder. Bortezomib (PS-341, Velcade™) is a novel proteosome inhibitor with significant activity in multiple myeloma, although subsets of patients remain refractory to the activity of the drug. Hence, better characterization of the interactions of this drug with classical resistance mechanisms may identify improved treatment applications. Materials and methods: We examined resistance mechanism after bortezomib treatment by using paired sensitive and resistant cell lines (MM1.S and OPM-2) in MM. As the cell lines used were not isogenic, we wanted to ensure that the changes seen were related to drug treatment only by using a corresponding solid tumor counterpart; thyroid carcinoma cell lines (KAT-18 and WRO). By using paired cell lines from different tumor types and applying a stringent exclusion criteria, any proteins that are related to cell line or cancer type phenomenon would be excluded and any protein changes seen would be related to ‘real’ changes that were attributed to bortezomib treatment. Samples were analysed using 2D-DIGE, a technique based on pre-electrophoretic labelling of samples with one of three spectrally resolvable fluorescent CyDyes (Cy2, Cy3, and Cy5) allowing multiplexing of samples into the same gel. All 2D-DIGE images were scanned and collected on a Typhoon Fluorescent Imager. Pooled samples were used as an internal standard to quantify expression changes with statistical significance. Statistics and quantitation of protein expression were carried out initially using DeCyder Biological Variation Analysis (BVA) software before performing subsequent Extended Data Analysis (EDA). Proteins of interest were picked from preparative gels and full scan mass spectra were recorded in profile mode and tandem mass spectra in centroid mode. The peptides were identified using the information in the tandem mass spectra by searching against the SWISS PROT database using SEQUEST. Results 18 proteins have been identified to be differentially expressed in the sensitive cell line compared to the resistant cell lines. 6 proteins were up-regulated and 12 down-regulated in the sensitive cell lines compared to the resistant cell lines (t-test 0.02) and all proteins were >1.3-fold differentially expressed. Of the proteins that are significantly changed, caspase 3 is down-regulated in sensitive cell lines after bortezomib treatment and heat shock protein 70 (Hsp70) is up-regulated. Caspase 3 is a key apoptosis executioner and is known to be responsible for the proteolytic cleavage of many proteins when cells are treated with bortezomib. Hsp70 is a chaperone protein for both proapoptotic and antiapoptotic proteins; it has been demonstrated to be upregulated with bortezomib treatment. These two proteins correlate with what is known about how bortezomib affects cells and validates our results. Other proteins that were significantly changed are involved in transcriptional regulation. These proteins provide an interesting insight into how bortezomib treatment affects cellular processes and provide clues into resistance mechanisms. Conclusion As the field is now aware, bortezomib is more than a proteosome inhibitor and it affects other pathways in cellular function which would be difficult to evaluate using conventional analytical methods. Proteomics is a novel way to evaluate bortezomib's effect in cellular pathways and also drug resistance mechanisms. We are in the process of validating the other novel proteins identified in our screen using small molecule inhibitors to these proteins and/or knockdown studies to validate these proteins even further. Disclosures Richardson: Millenium: Membership on an entity's Board of Directors or advisory committees, Research Funding; MLNM: speakers bureau up to 7/1/09; Celgene: Membership on an entity's Board of Directors or advisory committees, speakers bureau up to 7/1/09. Mitsiades:Novartis Pharmaceuticals: Consultancy, Honoraria; Milllennium: Consultancy, Honoraria; Bristol-Myers Squibb : Consultancy, Honoraria; Merck &Co.: Consultancy, Honoraria; Kosan Pharmaceuticals : Consultancy, Honoraria; Pharmion: Consultancy, Honoraria; PharmaMar: Patents & Royalties; Amgen: Research Funding; AVEO Pharma: Research Funding; EMD Serono: Research Funding; Sunesis Pharmaceuticals: Research Funding. Anderson:Millenium: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.

Tumor Cell-Dependent Differences in Stroma-Induced Changes to Bortezomib Sensitivity.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2468-2468
Author(s):  
Eugen Dhimolea ◽  
Jana Jakubikova ◽  
Richard W.J. Groen ◽  
Jake E. Delmore ◽  
Hannah M. Jacobs ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Cell Lines ◽  
Stromal Cells ◽  
Cell Response ◽  
Research Funding ◽  
Bioluminescence Imaging ◽  
Bortezomib Treatment ◽  
Rpmi 8226

Abstract Abstract 2468 In multiple myeloma (MM) and other hematologic malignancies, bone marrow stromal cells (BMSCs) confer resistance to diverse conventional or investigational therapeutics. During the last decade, data from many groups have concurred that the in vitro anti-MM activity of the proteasome inhibitor bortezomib is very similar in the presence and absence of BMSCs, including primary and immortalized BMSCs. These well-validated observations have supported the notion that novel, more effective, therapies for the treatment of MM should ideally be, similarly to bortezomib, capable of overcoming the protective effect of BMSCs. Interestingly, however, we have observed that primary CD138+ MM tumor cells isolated from patients with clinical refractoriness to bortezomib occasionally exhibit substantial in vitro response to clinically achievable concentrations of this drug. We therefore hypothesized that, under certain previously under-explored experimental settings, BMSCs may alter the threshold of MM cell response to bortezomib-induced apoptosis. To address this hypothesis in conditions that better simulate the clinical context, we conducted compartment-specific bioluminescence imaging (CS-BLI) assays to evaluate the effect of bortezomib on tumor cells co-cultured with BMSCs for different time periods prior to bortezomib administration. We observed that prolonged tumor-stromal co-culture (48–96hrs) prior to initiation of bortezomib treatment did not affect drug sensitivity for several MM cell lines (OPM2, H929, UM9, KMS11, KMS18 and RPMI-8226) tested. Prolonged co-culture of OPM1, RPMI-8226-Dox40, OCI-My5, KMS12BM and KMS18 cells prior to bortezomib treatment enhanced its activity. Importantly, extended co-culture of MM cell lines MM.1S and MM.1R with BMSCs prior to drug treatment induced significant attenuation of their response to bortezomib, as evidenced by 2–3 fold increase of IC50 values in several independent replicate experiments and a mean % area under the bortezomib dose response curve (AUC) of 5.82% vs 14.10% in the absence vs. presence of BMSCs, respectively (p=0.0079). Consistent with these in vitro results, heterotypic s.c. xenografts of Luc+ MM.1S cells mixed with Luc- BMSCs did not show statistically significant reduction in MM burden with bortezomib treatment (0.5 mg/kg s.c. twice weekly for 5 weeks) compared to vehicle-treated controls (p=0.1320), as quantified by bioluminescence imaging. In contrast, the same dose and schedule of bortezomib treatment significantly suppressed tumor burden, compared to vehicle-treated controls, of monotypic s.c. xenografts of Luc+ MM.1S cells in SCID mice (p=0.0022), as in prior experience. To evaluate the molecular mechanisms of cell non-autonomous decrease in MM cell response to bortezomib, we compared the transcriptional profiles of MM.1S cells in extended co-cultures with HS-5 BMSCs vs. MM.1S cells cultured in isolation. These studies identified a distinct transcriptional signature of stroma-induced transcripts, including several (e.g. PSMC3, ITGB7, FOS, ALDH1L2) for which transcript expression higher than the median levels for refractory MM patients correlated with shorter overall survival (p<0.02, log-rank tests) after treatment with bortezomib. These observations highlight the notion that tumor cell responses to a given agent in the presence of non-malignant stromal cells can exhibit substantial qualitative and quantitative variation, depending on the specific tumor cell type tested, as well as the particular stromal cell population and conditions of the co-culture. Our findings highlight the need to apply combinatorial high-throughput scalable platforms, such as CS-BLI, to evaluate the different permutations of interactions between tumor cells, non-malignant accessory cells of the microenvironment and administered therapeutics. This study also provides a comprehensive functional oncogenomic framework to identify prognostically relevant molecular mediators of stroma-induced resistance to therapy in MM. Disclosures: Groen: Genmab BV: Research Funding. McMilllin:Axios Biosciences: Equity Ownership. Mitsiades:Millennium Pharmaceuticals: Honoraria; Celgene: Honoraria; Novartis Pharmaceuticals: Honoraria; Bristol-Myers Squibb: Honoraria; Merck &Co.: Honoraria; Centocor: Honoraria; Arno Therapeutics: Honoraria; Amgen: Research Funding; AVEO Pharma: Research Funding; OSI: Research Funding; EMD Serono: Research Funding; Sunesis: Research Funding; Johnson & Johnson: Research Funding; PharmaMar: Licensing royalties Other; Axios Biosciences: Uncompensated Role as advisor, Uncompensated Role as advisor Other.

scholarly journals Tris DBA Palladium Overcomes Hypoxia Mediated Drug Resistance in Multiple Myeloma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2978-2978
Author(s):  
Pilar De La Puente ◽  
Barbara Muz ◽  
Feda Azab ◽  
Micah John Luderer ◽  
Jack L. Arbiser ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Flow Cytometry ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Cell Lines ◽  
Research Funding ◽  
Caspase 3 ◽  
Cellular Processes ◽  
Hypoxic Conditions

Abstract Introduction: Despite recent progress in novel and targeted therapies, multiple myeloma (MM) remains a therapeutically challenging incurable disease. The regulation of important cellular processes and its link to cancer presented Src as an attractive target for MM. Src is a non-receptor protein tyrosine kinase which regulates multiple fundamental cellular processes including cell growth, migration, survival and differentiation. Activated Src in cancer lead to studies with Src as a target for anti-cancer drugs, and numerous Src inhibitors have become available to test the importance of Src in tumor initiation and progression. In MM, it has been described that in cell lines and MM patient-derived tumors, c-Src is constitutively activated, which plays an important role in drug resistance mechanisms. Tris dibenzylideneacetone dipalladium (Tris DBA), a small-molecule palladium complex, was shown to reduce Src/NMT-1 complex in melanoma cells, as well as inhibit downstream signaling including mitogen-activated protein kinase (MAPK kinase) and phosphoinositol-3-kinase (PI3K). We suggest a novel strategy to improve the treatment of MM and overcome the drug resistance for the current therapeutic agents by specific inhibition of Src in MM cells by an organopalladium compound, Tris DBA. Methods: Tris DBA was prepared by Dr. Arbiser. MM cell lines (MM.1S, MM.1R, H929, RPMI-8826, and OPM2) and PBMCs were cultured with Tris DBA (0-10 µM) for 24h. MM cells were analyzed for cell proliferation by MTT assay; cell cycle by DNA staining with PI and analyzed by flow cytometry; apoptosis was analyzed by Annexin V/PI staining and analyzed by flow cytometry; and cell signaling associated with proliferation, cell cycle, and apoptosis was analyzed by western blotting. In addition, cell proliferation assay of Tris DBA with or without combination of proteasome inhibitors (PIs) bortezomib or carfilzomib for 24h was analyzed on the proliferation of MM cells in normoxic or hypoxic conditions. Moreover, we tested the effect of combination treatment on cell cycle and apoptosis signaling under normoxic conditions. We then evaluated the effect of Tris DBA on HIF1α expression, migration and drug resistance under normoxic or hypoxic conditions. Results: The Src inhibitor Tris DBA reduced the proliferation of MM cell lines with an IC50 of about 1.5 - 3 µM after 24h treatment as a single agent, while none of the normal PBMC controls showed effect on their proliferation in the same dose range. These results were consistent with the decreased expression of proliferation signaling proteins from MAPK pathways (pERK), as well as PI3K (pS6R). Src inhibition led to the induction of a sub-G1 peak, which indicated accumulating apoptotic cells shown by DNA staining with PI. Apoptosis was then analyzed by Annexin/PI and confirmed by cleavage of caspase-3 and PARP. We found that Tris DBA synergized with bortezomib and carfilzomib by inhibiting proliferation of MM cells and reducing cell cycle protein signaling more than either of the drugs alone. Moreover, the Tris DBA/Bortezomib or Tris DBA/Carfilzomib combination therapies significantly increased apoptosis by caspase-3 cleavage more than treatment with either proteasome inhibitor individually. Tris DBA inhibited HIF1α expression in both normoxic and hypoxic conditions. HIF1α is an important target for hypoxia-driven drug resistance. Our studies confirmed hypoxia promoted faster chemotaxis of MM cells towards the chemo-attractants found in stromal cell conditioned media, and that Tris DBA treatment could overcome this hypoxia-induced effect. In addition, the development of hypoxia-induced drug resistance to individual bortezomib or carfilzomib treatment was overcome with combination treatment of Tris DBA under hypoxic conditions. Conclusions: Tris DBA reduces proliferation and induces G1 arrest and apoptosis in MM cells. Tris DBA synergized with PIs reducing proliferation and cell cycle signaling, as well as increasing apoptosis more than each drug alone. Tris DBA overcame hypoxia-induced effects such as enhanced chemotaxis or drug resistance to PIs by inhibition of HIF1α expression. Moreover, we found that Tris DBA is an effective anti-myeloma agent alone or in combination with other targeted drugs and that it reverses hypoxia-induced drug resistance in myeloma. These results suggest the use of Tris DBA as a new therapeutic agent in relapsed refractory myeloma. Disclosures Arbiser: ABBY Therapeutics: Other: Jack L Arbiser is listed as inventor on a US Patent for imipramine blue. He is cofounder of ABBY Therapeutics, which has licensed imipramine blue from Emory University.. Azab:Verastem: Research Funding; Targeted Therapeutics LLC: Other: Founder and owner ; Selexys: Research Funding; Karyopharm: Research Funding; Cell Works: Research Funding.

scholarly journals Novel Combination Therapy Targeting rDNA Transcription and Histone Deacetylation Provides Effective Treatment for Multiple Myeloma, and Synergises in Bortezomib-Resistant MM

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1945-1945
Author(s):  
Kylee H Maclachlan ◽  
Andrew Cuddihy ◽  
Nadine Hein ◽  
Carleen Cullinane ◽  
Simon J. Harrison ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Drug Resistance ◽  
Cell Lines ◽  
Cellular Response ◽  
Single Agent ◽  
Resistant Cell ◽  
Rdna Transcription

Abstract Background: Multiple myeloma (MM) requires combination drug therapies to delay acquired drug resistance and clinical relapse. We co-developed CX-5461, a highly-selective inhibitor of RNA polymerase I-mediated rDNA transcription(1), currently in phase I trials for relapsed haematological malignancies (Peter Mac). CX-5461 produces a targeted nucleolar DNA damage response (DDR), triggering both a p53-dependent and -independent nucleolar stress response and killing malignant cells while sparing normal cells(2,3). Single-agent CX-5461 provides an impressive survival benefit in mouse models of B-cell lymphoma, acute myeloid leukaemia and now MM(2,4,5). However, drug resistance eventually occurs, confirming the need for combination therapies. Aim: To test the efficacy of CX-5461 in combination with the histone deacetylase inhibitor panobinostat, (prioritised from a boutique high-throughput screen of anti-myeloma agents), with a focus on the setting of resistance to proteasome-inhibitors (PIs). Methods: We assessed the impact of CX-5461 and panobinostat on overall survival in mouse models of MM, then surveyed the effects on cellular response and molecular markers of DDR. We developed bortezomib-resistant cell lines and an in vivo model of bortezomib-resistance to test this combination in the setting of PI-resistance. Results: CX-5461 in combination with panobinostat provides a significant survival advantage in both the transplanted Vk*MYC and the 5T33/KaLwRij models, with minimal bone marrow toxicity. The combination showed increased anti-proliferative effects and cell death in vitro. Interestingly, experiments interrogating the downstream cellular response of this combination suggest that the mechanism(s) driving synergy are complex and cell context-dependent. Cell cycle analysis indicates that both CX-5461- and panobinostat-driven cell cycle effects, i.e. G2/M and G1/S arrest, respectively, are dominant in the combination setting in a cell line-dependent manner, suggesting that context-dependent factors such as p53 may influence the cellular response. Mechanistically, in both p53-wild type and -null cell lines we observe an increase in DDR signalling with single agent CX-5461, with only moderate further increase with the combination. Moreover, CX-5461-mediated MYC downregulation is not universally observed, with the combination promoting further downregulation only in some cell lines. Given the potential for affecting global transcription programs downstream of panobinostat, we are performing transcriptome analyses in the combination setting compared to single agent treatment. We have generated bortezomib-resistant cell lines, sequentially increasing drug exposure to establish populations growing at concentrations above the IC90 of the parental lines. The resistant 5T33 cells retain their resistance to bortezomib in vivo and we have demonstrated that CX-5461 remains effective in this model, significantly increasing survival. We are currently examining the combination of CX-5461 with panobinostat in this model of bortezomib-resistance, which will give critical information guiding patient selection for future clinical trials. Conclusion: The rDNA transcription inhibitor CX-5461 synergises in vitro and in vivo with panobinostat, and CX-5461 retains efficacy in the setting of bortezomib-resistant myeloma. References Drygin et al., Cancer Research 2011 Bywater et al., Cancer Cell 2012 Quin et al, Oncotarget, 2016 Devlin et al., Cancer Discovery 2016 Hein et al., Blood 2017 Disclosures Harrison: Janssen-Cilag: Other: Scientific advisory board.

scholarly journals Understanding the Role of Extracellular Vesicles in Lenalidomide-Resistance Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1887-1887
Author(s):  
Tomofumi Yamamoto ◽  
Nobuyoshi Kosaka ◽  
Ochiya Takahiro ◽  
Yutaka Hattori
Keyword(s):  
Bone Marrow ◽  
Drug Resistance ◽  
Cell Line ◽  
Cell Lines ◽  
Parental Cell ◽  
Resistant Cell ◽  
Bone Marrow Microenvironment ◽  
Drug Resistant ◽  
Apoptosis Assay ◽  
Drug Resistant Cell

Abstract Multiple myeloma (MM) is a plasma cell malignancy that develops by the accumulation of various genetic abnormalities. In recent years, the prognosis of MM has improved by the development of novel drugs including immunomodulatory drugs (IMiDs), proteasome inhibitors, and antibody drugs. However, MM cells acquired drug resistance by long-term exposure to these therapeutic drugs. MM is a multiclonal disease, and various clone subtypes develop within the bone marrow microenvironment. It has been suggested that drug resistant phenotype could transmit from resistant clones to sensitive ones, and also to immune cells, or mesenchymal stem cells, resulting in the change of bone marrow microenvironment suitable for MM cell survival. It has been shown that extracellular vesicles (EVs) are one of the means of information transmission. EVs are secreted from almost all cells, and the amount of EV secretion is particular high from cancer cells. It was already known that cancer-derived EVs transmitted information associated with cancer progressions such as angiogenesis, metastasis, and drug resistance to the surrounding cells. Thus, EVs were proposed to play an important role in acquisition of drug resistance even though the mechanisms have not been fully understood in MM. In order to understand the mechanism of drug resistance in MM mediated by EVs, lenalidomide resistant cell lines were established by long-term exposure of lenalidomide. The amount of EVs was measured by ExoScreen, which is ultra-sensitive detection method of EVs by measuring surface protein of EVs, such as, CD9 and CD63, and by the nanoparticle tracking analysis. We found that lenalidomide resistant cell lines in KMS21R, KMS27R and KMS34R cell lines secreted about twice more EVs than their parental cell lines, and the amount of EV secretion was correlated with the drug sensitivity of lenalidomide. Suppression of EV secretion by knockdown of TSG101, which is known for EV secretion-associated protein, did not affect lenalidomide resistance. We could suppress the EV secretion to two-thirds, however cell proliferation and caspase activity were not change. From these results, we postulated the two possibilities; 1) EV secretion pathway other than TSG101 is associated with drug resistance via EVs; 2) EV derived from lenalidomide resistant cells can affect the cells exist in bone marrow microenvironment. From these hypotheses, we have done the following experiments. Firstly, to identify the genes which involved in EV secretion pathway associated with drug resistance, RNA sequence among the drug-resistant cell lines and their parental cell lines was performed. Drug resistant cell lines had some genetic abnormality, for instance immune system or angiogenesis. Now, we are detecting the EV secretion associated genes in drug resistant cell lines. Secondly, EV derived from the drug-resistant cell lines and EV derived from the parent cell lines were added to drug sensitive MM cell lines, then lenalidomide is added after 24hr. The cell proliferation and apoptosis assay were evaluated after 48hr. EV derived from the drug-resistant cell lines in KMS34R cell line significantly inhibited cell death measured by MTS assay and apoptosis assay compared with those from the drug sensitive KMS21 and KMS34 cell lines. EVs from KMS34R cell line, which is the most progressed cell line we established, could more transmit drug resistance than those from other cell lines. These results suggested that drug resistance was transmitted from drug-resistant cell lines to non-resistant cell lines via EVs. Now, we are analyzing the component of EV from drug-resistant MM cells by proteome analysis to identify the molecules associated with lenalidomide resistance in MM. In addition, we are investigating the molecules which associated with the secretion of EVs from drug-resistance MM. These results prompted us to hypothesize that attenuating the function of a molecule responsible for EV secretion could lead to the inhibition of cancer development such as drug resistance. It is expected that EVs will be novel therapeutic targets in refractory or relapsed MM. Disclosures Hattori: IDAC inc.: Research Funding; Takeda: Research Funding.

Establishment and Indentification of Genetic Alterations in Chemotherapy-Resistant T-ALL Cell Lines.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4423-4423
Author(s):  
David A. Estes ◽  
Rahul Poria ◽  
Debbie M. Lovato ◽  
Hadya M. Khawaja ◽  
Claudia L. Quan ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Line ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Acquired Resistance ◽  
Genetic Alterations ◽  
Resistant Cell ◽  
Multi Drug Resistance ◽  
Growth Media ◽  
Drug Resistant

Abstract Acquisition of drug resistance in tumor cells in children with T-cell acute lymphoblastic leukemia (T-ALL) during chemotherapy results in relapse and poor outcome. T-ALL cell lines that have acquired resistance to chemotherapeutics are therefore critical tools for the study of acquired resistance, yet there is a paucity of cell lines available for study. In this study, we hypothesize that drug resistant T-ALL cells can be produced by prolonged exposure to chemotherapeutics and that microarray analysis can be employed to identify the gene products responsible for acquired drug resistance. By incrementally increasing the drug concentration in growth media, we have produced T-ALL cell lines (Jurkat and Sup T1) that grow well in the presence of therapeutic concentrations of L-asparaginase (ASNase) and daunorubicin (DNR). The genetic profiles of the drug-resistant cell lines were compared to their parental progenitors using the Affymetrix HG-U133Plus2 GeneChip platform, capable of hybridizing ~54,000 genes and ESTs/chip. Signal intensity was normalized using the robust multi-array average (RMA) technique in GeneSpring 7.2. The Sup T1 and Jurkat ASNase-resistant cell lines increased their IC50s 26-fold (0.044 IU/mL to 1.14 IU/mL) and 320-fold (0.003 IU/mL to 0.96 IU/mL), respectively. The IC50 of the Jurkat DNR resistant cell line increased 77-fold (30 nM to 2300 nM), and 4.0-fold, (0.46 nM to 1.85 nM), respectively. Notably, DNR resistant Jurkat cells were also resistant to therapeutic concentrations of vincristine and prednisolone, but not ASNase. In contrast, the ASNase resistant cell lines remained sensitive to DNR, vincristine, and prednisolone. Microarray data comparing DNR-resistant and parental cell lines showed 288 genes upregulated >1.5-fold in the resistant line. Two sets of genes were the most upregulated in the drug resistant cells in comparison to parental cells. ABCB1 (ABC transporter P-glycoprotein) was upregulated ~940-fold and genes coding for 6 different killer-cell immunoglobulin-like receptors (KIRs) were upregulated >6-fold. In the case of the ASNase-resistant cell lines, 96 genes were found to be upregulated >1.5-fold in both Jurkat and Sup T1 lines. The most highly upregulated gene in both cell lines was argininosuccinate synthase (ASS), 32-fold upregulated in Jurkat and 6.5-fold in Sup T1. All expression results were confirmed by qRT-PCR. These genes have previously been implicated in the acquisition of drug resistance: ASS is critical for responding to asparagine depletion caused by ASNase. ABCB1 acts as a molecular pump capable of lowering intracellular concentrations of substrate chemotherapeutics such as DNR, vincristine, and prednisolone, consistent with our observation of multi-drug resistance in that cell line. To our knowledge, this is the first description of DNR and ASNase resistant Jurkat and Sup T1 T-ALL cell lines. In addition, our results suggest that microarray technology is a valid method for elucidating the genetic nature of drug resistance in T-ALL cell lines, making it a productive approach to identify mechanisms of chemotherapy resistance. Finally, these cell lines will serve as useful tools for studying mechanisms of chemotherapeutic resistance in T-ALL.

scholarly journals The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Cisplatin- and Paclitaxel-Resistant Ovarian Cancer Cell Lines

2022 ◽  
Vol 23 (1) ◽  
pp. 526
Author(s):  
Dominika Kazmierczak ◽  
Karol Jopek ◽  
Karolina Sterzynska ◽  
Michal Nowicki ◽  
Marcin Rucinski ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Drug Resistance ◽  
Cell Lines ◽  
Cancer Cell ◽  
Resistance Genes ◽  
Ovarian Cancer Cell ◽  
Ovarian Cancer Cell Line ◽  
Resistant Cell ◽  
Drug Resistant ◽  
Resistant Genes

Ovarian cancer is the most lethal gynecological malignancy. The high mortality results from late diagnosis and the development of drug resistance. Drug resistance results from changes in the expression of different drug-resistance genes that may be regulated miRNA. The main aim of our study was to detect changes in miRNA expression levels in two cisplatin (CIS) and two paclitaxel (PAC)—resistant variants of the A2780 drug-sensitive ovarian cancer cell line—by miRNA microarray. The next goal was to identify miRNAs responsible for the regulation of drug-resistance genes. We observed changes in the expression of 46 miRNA that may be related to drug resistance. The overexpression of miR-125b-5p, miR-99a-5p, miR-296-3p, and miR-887-3p and downregulation of miR-218-5p, miR-221-3p, and miR-222-3p was observed in both CIS-resistant cell lines. In both PAC-resistant cell lines, we observed the upregulation of miR-221-3p, miR-222-3p, and miR-4485, and decreased expression of miR-551b-3p, miR-551b-5p, and miR-218-5p. Analysis of targets suggest that expression of important drug-resistant genes like protein Tyrosine Phosphatase Receptor Type K (PTPRK), receptor tyrosine kinase—EPHA7, Semaphorin 3A (SEMA3A), or the ATP-binding cassette subfamily B member 1 gene (ABCB1) can be regulated by miRNA.

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