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Rogers KA, Huang Y, Abruzzo L, Bhat SA, Doong TJ, Kittai A, Lozanski A, Lozanski G, Lucas M, Maddocks KJ, Mao C, Nussbaum M, Sass EJ, Suresh S, Byrd JC, Woyach JA. Four-year follow-up from a phase 2 study of obinutuzumab, ibrutinib, and venetoclax in CLL. J Clin Oncol 2022. [DOI: 10.1200/jco.2022.40.16_suppl.7540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
7540 Background: Targeted agent combinations for chronic lymphocytic leukemia (CLL) have resulted in safe regimens with improved progression-free survival (PFS) compared to chemoimmunotherapy. The optimal regimen and long-term outcomes remain unknown. We conducted a phase 2 study of obinutuzumab (OBIN), ibrutinib (IBR), and venetoclax (VEN) in relapsed/refractory (RR) and treatment-naïve (TN) CLL patients (pts) and report extended follow up on two previously reported cohorts (RR, TN 1) and a new cohort of identically treated TN pts (TN 2). Methods: Pts with TN or RR (≥1 prior treatment) CLL requiring treatment were eligible. Treatment was given for 14 28-day cycles (C). OBIN was started C1, IBR C2, and VEN C3 with standard dose escalation. Response was assessed 2 months (mos) after C14 (EOT) by iwCLL 2008 criteria. Minimal residual disease (MRD) was measured by 10-color flow cytometry with a cutoff of < 1x10-4. The primary endpoint was complete remission (CR) with undetectable MRD (uMRD) in blood and bone marrow at EOT. A sample size of 25 pts per cohort achieves 90% power to test the null hypothesis of 10% against 30% with 1-sided α of 10%. The Kaplan-Meier method was used to estimate PFS and overall survival (OS). Results: 75 pts were treated in 3 cohorts (Table). Data are as of 1/3/2022. In the TN 2 cohort, the overall response rate (ORR) at EOT was 96% (95% CI: 80-100) and CR with uMRD was 20% (95% CI: 7-41). The ORR for TN 1 and TN 2 combined was 90% (95% CI: 78-97) and CR with uMRD was 24% (95% CI: 13-38). Median follow up was 56 (0-65), 57 (7-63), and 30 (24-35) mos, respectively, for RR, TN 1, and TN 2. There were 3 deaths (RR = 1, TN 1 = 1, TN 2 = 1) and 6 disease progressions (RR = 4, TN 1 = 2, TN 2 = 0). Estimated 48-month PFS for TN 1 and RR cohorts were both 96% (95% CI: 72-99) and OS was 85% (95% CI: 60-95) and 100%, respectively. The estimated 24-month PFS and OS for TN 2 were both 96% (95% CI: 75-99). The most frequent adverse events were neutropenia (95%, 73% grade ≥3), leukopenia (95%, 45% grade ≥3), lymphopenia (93%, 40% grade ≥3), and thrombocytopenia (91%, 28% grade ≥3). The only grade ≥3 non-hematologic toxicity occurring at ≥20% was hypertension (85%, 39% grade ≥3). Atrial fibrillation occurred in 11% of pts. Conclusions: At extended follow-up, remissions remain durable after fixed duration OBIN, IBR, and VEN. The efficacy and acceptable safety justify further study and are being compared to IBR and OBIN in 2 phase 3 US cooperative group trials. Clinical trial information: NCT02427451. [Table: see text]
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Affiliation(s)
| | - Ying Huang
- Division of Hematology, The Ohio State University, Columbus, OH
| | - Lynne Abruzzo
- Department of Pathology, The Ohio State University, Columbus, OH
| | - Seema Ali Bhat
- Division of Hematology, The Ohio State University, Columbus, OH
| | - Tzyy-Jye Doong
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Adam Kittai
- Division of Hematology, The Ohio State University, Columbus, OH
| | - Arletta Lozanski
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Gerard Lozanski
- Department of Pathology, The Ohio State University, Columbus, OH
| | - Margaret Lucas
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | | | - Charelen Mao
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Megan Nussbaum
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Ellen J Sass
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - Swetha Suresh
- The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | - John C. Byrd
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH
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Elgamal S, Cocucci E, Sass EJ, Mo XM, Blissett AR, Calomeni EP, Rogers KA, Woyach JA, Bhat SA, Muthusamy N, Johnson AJ, Larkin KT, Byrd JC. Optimizing extracellular vesicles' isolation from chronic lymphocytic leukemia patient plasma and cell line supernatant. JCI Insight 2021; 6:e137937. [PMID: 34369387 PMCID: PMC8410027 DOI: 10.1172/jci.insight.137937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In chronic lymphocytic leukemia (CLL) and very likely all cancer types, extracellular vesicles (EVs) are a common mechanism by which intercellular messages are communicated between normal, diseased, and transformed cells. Studies of EVs in CLL and other cancers have great variability and often lack reproducibility. For CLL patient plasma and cell lines, we sought to characterize current approaches used in isolating EV products and understand whether cell culture-conditioned media or complex biological fluids confound results. Utilizing nanoparticle tracking analysis, protein quantification, and electron microscopy, we show that ultracentrifugation with an OptiPrep cushion can effectively minimize contaminants from starting materials including plasma and conditioned media of CLL cell lines grown in EV-depleted complete RPMI media but not grown in the serum-free media AIM V commonly used in CLL experimental work. Moreover, we confirm the benefit of including 25 mM trehalose in PBS during EV isolation steps to reduce EV aggregation, to preserve function for downstream applications and characterization. Furthermore, we report the highest particles/μg EVs were obtained from our CLL cell lines utilizing the CELLine bioreactor flask. Finally, we optimized a proliferation assay that offers a functional evaluation of our EVs with minimal sample requirements.
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Affiliation(s)
- Sara Elgamal
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center
| | - Emanuele Cocucci
- Comprehensive Cancer Center.,Division of Pharmaceutics, College of Pharmacy
| | - Ellen J Sass
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center
| | - Xiaokui M Mo
- Comprehensive Cancer Center.,Department of Biomedical Informatics, College of Medicine
| | | | | | - Kerry A Rogers
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center
| | - Jennifer A Woyach
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center
| | - Seema A Bhat
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center
| | - Natarajan Muthusamy
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center.,College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Amy J Johnson
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center.,Division of Pharmaceutics, College of Pharmacy
| | - Karilyn T Larkin
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center
| | - John C Byrd
- Division of Hematology, Department of Internal Medicine, College of Medicine.,Comprehensive Cancer Center.,Division of Pharmaceutics, College of Pharmacy.,College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
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3
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Lakshmanan A, Tsai YT, Lehman A, Sass EJ, Tran M, Lucas F, Long M, Harrington BK, Perle KL, Coppola V, Lozanski G, Muthusamy N, Byrd JC, Grever MR, Lucas DM. Abstract 1029: MAPK-mediated immunomodulation in disseminated murine Emu-TCL1 chronic lymphocytic leukemia. Cancer Res 2017. [DOI: 10.1158/1538-7445.am2017-1029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Work in melanoma and other solid tumors shows mutations activating MAPK pathway not only promote malignancy by promoting survival and proliferation but also are immunosuppressive than wild-type (WT) counterparts. However, relevance of MAPK-activating mutations to immune modulation in disseminated cancers such as leukemia is uncertain, and the mechanisms by which this occurs are likely to differ. BRAF activating mutation is found in nearly all hairy cell leukemia cases, 4% of chronic lymphocytic leukemia (CLL) and 9% CLL cases when including other MAPK-activating mutations such as KRAS and NRAS. To assess immunomodulatory effects of BRAF-mutant CLL cells, we co-cultured dox-inducible OSU-CLL cells transfected with WT or BRAFV600E constructs with healthy donor T cells incubated with anti-CD3/anti-CD28 antibodies, and T cell proliferation, cytokine production and expression of surface proteins were assessed by flow cytometry. We also employed a transgenic mouse model of BRAF B cell leukemia. CD19-Cre x BRAFV600E or CD19-Cre only mice were crossed with the well-characterized Emu-TCL1 model of CLL to obtain mice with spontaneous B cell leukemia expressing either WT BRAF (CD19-Cre xTCL1) or mutant BRAF (BRAFV600E xCD19-Cre xTCL1) under the native BRAF promoter. For adoptive transfer (AT) experiments, leukemia cells (2e7) from transgenic mice were engrafted intravenously into syngeneic healthy adult animals. Blood and spleen cells were examined by flow cytometry. OSU-CLL cells expressing BRAFV600E more strongly inhibited anti-CD3/CD28-induced proliferation of normal donor T cells. Transwell assays showed this effect was due both to soluble and contact-dependent factors. TNF levels were higher in BRAFV600E-expressing cells and reduced by vemurafenib, but a TNF neutralizing antibody did not alter the inhibitory effect of BRAFV600E-expressing cells on T cell proliferation. Proliferation was rescued by the BRAFV600E inhibitor dabrafenib, further supporting the contribution of mutant BRAF to this effect. Impact of BRAFV600E mutation on myeloid compartment was also evaluated using AT model. Mice were engrafted with BRAFWT or BRAFV600E leukemia cells, and upon achieving similar disease loads, BRAFV600E leukemic B cells caused 2.2-fold increase in PD-L1 expressing-peripheral myeloid cells (p<0.001; n=25 WT; 11 mutant). Additionally, there was an increase in F4/80+ macrophages (11%; p=0.002), CD11b+Ly6CintLy6Ghi MDSCs (8.5%, p=0.014) and decrease in CD11b+Ly6CloLy6Glo patrolling monocytes (11%; p=0.031; n=33 WT; 40 mutant) in spleens of mice with BRAFV600E leukemia, indicating that this mutation influences the myeloid cell compartment as well. Ongoing studies are investigating the mechanism of these effects and the potential for pharmacologic reversal. Together, these results demonstrate immunosuppressive impact of BRAF in B-cell leukemia.
Citation Format: Aparna Lakshmanan, Yo-Ting Tsai, Amy Lehman, Ellen J. Sass, Minh Tran, Fabienne Lucas, Meixiao Long, Bonnie K. Harrington, Krista La Perle, Vincenzo Coppola, Gerard Lozanski, Natarajan Muthusamy, John C. Byrd, Michael R. Grever, David M. Lucas. MAPK-mediated immunomodulation in disseminated murine Emu-TCL1 chronic lymphocytic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1029. doi:10.1158/1538-7445.AM2017-1029
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Affiliation(s)
| | | | | | | | - Minh Tran
- The Ohio State University, Columbus, OH
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Ren Y, Chen WL, Lantvit DD, Sass EJ, Shriwas P, Ninh TN, Chai HB, Zhang X, Soejarto DD, Chen X, Lucas DM, Swanson SM, Burdette JE, Kinghorn AD. Cardiac Glycoside Constituents of Streblus asper with Potential Antineoplastic Activity. J Nat Prod 2017; 80:648-658. [PMID: 27983842 PMCID: PMC5365359 DOI: 10.1021/acs.jnatprod.6b00924] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Three new (1-3) and two known (4 and 5) cytotoxic cardiac glycosides were isolated and characterized from a medicinal plant, Streblus asper Lour. (Moraceae), collected in Vietnam, with six new analogues and one known derivative (5a-g) synthesized from (+)-strebloside (5). A preliminary structure-activity relationship study indicated that the C-10 formyl and C-5 and C-14 hydroxy groups and C-3 sugar unit play important roles in the mediation of the cytotoxicity of (+)-strebloside (5) against HT-29 human colon cancer cells. When evaluated in NCr nu/nu mice implanted intraperitoneally with hollow fibers facilitated with either MDA-MB-231 human breast or OVCAR3 human ovarian cancer cells, (+)-strebloside (5) showed significant cell growth inhibitory activity in both cases, in the dose range 5-30 mg/kg.
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Affiliation(s)
- Yulin Ren
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States
| | - Wei-Lun Chen
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Daniel D. Lantvit
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Ellen J. Sass
- Division of Hematology, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, United States
| | - Pratik Shriwas
- Department of Biological Sciences, Ohio University, Athens, OH 45701, United States
- Edison Biotechnology Institute, Ohio University, Athens, OH 45701, United States
- Molecular and Cellular Biology Program, Ohio University, Athens, OH 45701, United States
| | - Tran Ngoc Ninh
- Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Hee-Byung Chai
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States
| | - Xiaoli Zhang
- Center for Biostatistics, The Ohio State University, Columbus, OH 43210, United States
| | - Djaja D. Soejarto
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, United States
- Science and Education, Field Museum of Natural History, Chicago, IL 60605, United States
| | - Xiaozhuo Chen
- Department of Biological Sciences, Ohio University, Athens, OH 45701, United States
- Edison Biotechnology Institute, Ohio University, Athens, OH 45701, United States
- Molecular and Cellular Biology Program, Ohio University, Athens, OH 45701, United States
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, United States
| | - David M. Lucas
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States
- Division of Hematology, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210, United States
| | - Steven M. Swanson
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, United States
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Joanna E. Burdette
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - A. Douglas Kinghorn
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States
- Corresponding Author.
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5
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Tsai YT, Lozanski G, Lehman A, Sass EJ, Hertlein E, Salunke SB, Chen CS, Grever MR, Byrd JC, Lucas DM. BRAF V600E induces ABCB1/P-glycoprotein expression and drug resistance in B-cells via AP-1 activation. Leuk Res 2015; 39:S0145-2126(15)30371-4. [PMID: 26350141 PMCID: PMC4779435 DOI: 10.1016/j.leukres.2015.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 08/25/2015] [Indexed: 12/15/2022]
Abstract
A subset of patients with chronic lymphocytic leukemia (CLL) and nearly all patients with classic hairy cell leukemia (HCL) harbor somatic BRAF activating mutations. However, the pathological role of activated BRAF in B-cell leukemia development and progression remains unclear. In addition, although HCL patients respond well to the BRAFV600E inhibitor vemurafenib, relapses are being observed, suggesting the development of drug resistance in patients with this mutation. To investigate the biological role of BRAFV600E in B-cell leukemia, we generated a CLL-like B-cell line, OSUCLL, with doxycycline-inducible BRAFV600E expression. Microarray and real-time PCR analysis showed that ABCB1 mRNA is upregulated in these cells, and P-glycoprotein (P-gp) expression as well as function were confirmed by immunoblot and rhodamine exclusion assays. Additionally, pharmacological inhibition of BRAFV600E and MEK alleviated the BRAFV600E-induced ABCB1/P-gp expression. ABCB1 reporter assays and gel shift assays demonstrated that AP-1 activity is crucial in this mechanism. This study, uncovers a pathological role for BRAFV600E in B-cell leukemia, and provides further evidence that combination strategies with inhibitors of BRAFV600E and MEK can be used to delay disease progression and occurrence of resistance.
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Affiliation(s)
- Yo-Ting Tsai
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Gerard Lozanski
- Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Amy Lehman
- Center for Biostatistics, The Ohio State University, Columbus, OH, USA
| | - Ellen J Sass
- Department of Internal Medicine, College of Medicine; The Ohio State University, Columbus, OH, USA
| | - Erin Hertlein
- Department of Internal Medicine, College of Medicine; The Ohio State University, Columbus, OH, USA
| | - Santosh B Salunke
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Ching-Shih Chen
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Michael R Grever
- Department of Internal Medicine, College of Medicine; The Ohio State University, Columbus, OH, USA
| | - John C Byrd
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH, USA; Department of Internal Medicine, College of Medicine; The Ohio State University, Columbus, OH, USA
| | - David M Lucas
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH, USA; Department of Internal Medicine, College of Medicine; The Ohio State University, Columbus, OH, USA.
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6
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Awan FT, Flynn JM, Jones JA, Andritsos LA, Maddocks KJ, Sass EJ, Lucas MS, Chase W, Waymer S, Ling Y, Jiang Y, Phelps MA, Byrd JC, Lucas DM, Woyach JA. Phase I dose escalation trial of the novel proteasome inhibitor carfilzomib in patients with relapsed chronic lymphocytic leukemia and small lymphocytic lymphoma. Leuk Lymphoma 2015; 56:2834-40. [PMID: 25669927 DOI: 10.3109/10428194.2015.1014368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The proteasome complex degrades proteins involved in a variety of cellular processes and is a powerful therapeutic target in several malignancies. Carfilzomib is a potent proteasome inhibitor which induces rapid chronic lymphocytic leukemia (CLL) cell apoptosis in vitro. We conducted a phase I dose-escalation trial to determine the safety and tolerability of carfilzomib in relapsed/refractory CLL or small lymphocytic lymphoma (SLL). Nineteen patients were treated with carfilzomib initially at 20 mg/m(2), then escalated in four cohorts (27, 36, 45 and 56 mg/m(2)) on days 1, 2, 8, 9, 15 and 16 of 28-day cycles. Therapy was generally well tolerated, and no dose limiting toxicities were observed. The most common hematologic toxicities were thrombocytopenia and neutropenia. All patients evaluable for response had stable disease, including patients with del17p13 and fludarabine-resistant disease. This trial shows acceptable tolerability and limited preliminary efficacy of carfilzomib in CLL and SLL.
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Affiliation(s)
- Farrukh T Awan
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Joseph M Flynn
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Jeffrey A Jones
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Leslie A Andritsos
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Kami J Maddocks
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Ellen J Sass
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Margaret S Lucas
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Weihong Chase
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Sharon Waymer
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Yonghua Ling
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Yao Jiang
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Mitch A Phelps
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - John C Byrd
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - David M Lucas
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
| | - Jennifer A Woyach
- a The Ohio State University Comprehensive Cancer Center , Columbus , OH , USA
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7
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Gupta SV, Hertlein E, Lu Y, Sass EJ, Lapalombella R, Chen TL, Davis ME, Woyach JA, Lehman A, Jarjoura D, Byrd JC, Lucas DM. The proteasome inhibitor carfilzomib functions independently of p53 to induce cytotoxicity and an atypical NF-κB response in chronic lymphocytic leukemia cells. Clin Cancer Res 2013; 19:2406-19. [PMID: 23515408 DOI: 10.1158/1078-0432.ccr-12-2754] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The proteasome consists of chymotrypsin-like (CT-L), trypsin-like, and caspase-like subunits that cleave substrates preferentially by amino acid sequence. Proteasomes mediate degradation of regulatory proteins of the p53, Bcl-2, and nuclear factor-κB (NF-κB) families that are aberrantly active in chronic lymphocytic leukemia (CLL). CLL remains an incurable disease, and new treatments are especially needed in the relapsed/refractory setting. We therefore investigated the effects of the proteasome inhibitor carfilzomib (CFZ) in CLL cells. EXPERIMENTAL DESIGN Tumor cells from CLL patients were assayed in vitro using immunoblotting, real-time polymerase chain reaction, and electrophoretic mobility shift assays. In addition, a p53 dominant-negative construct was generated in a human B-cell line. RESULTS Unlike bortezomib, CFZ potently induces apoptosis in CLL patient cells in the presence of human serum. CLL cells have significantly lower basal CT-L activity compared to normal B and T cells, although activity is inhibited similarly in T cells versus CLL. Co-culture of CLL cells on stroma protected from CFZ-mediated cytotoxicity; however, PI3K inhibition significantly diminished this stromal protection. CFZ-mediated cytotoxicity in leukemic B cells is caspase-dependent and occurs irrespective of p53 status. In CLL cells, CFZ promotes atypical activation of NF-κB evidenced by loss of cytoplasmic IκBα, phosphorylation of IκBα, and increased p50/p65 DNA binding, without subsequent increases in canonical NF-κB target gene transcription. CONCLUSIONS Together, these data provide new mechanistic insights into the activity of CFZ in CLL and support phase I investigation of CFZ in this disease.
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Affiliation(s)
- Sneha V Gupta
- College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
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Gupta SV, Sass EJ, Davis ME, Edwards RB, Lozanski G, Heerema NA, Lehman A, Zhang X, Jarjoura D, Byrd JC, Pan L, Chan KK, Kinghorn AD, Phelps MA, Grever MR, Lucas DM. Resistance to the translation initiation inhibitor silvestrol is mediated by ABCB1/P-glycoprotein overexpression in acute lymphoblastic leukemia cells. AAPS J 2011; 13:357-64. [PMID: 21538216 DOI: 10.1208/s12248-011-9276-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/19/2011] [Indexed: 01/06/2023]
Abstract
Protein synthesis is a powerful therapeutic target in leukemias and other cancers, but few pharmacologically viable agents are available that affect this process directly. The plant-derived agent silvestrol specifically inhibits translation initiation by interfering with eIF4A/mRNA assembly with eIF4F. Silvestrol has potent in vitro and in vivo activity in multiple cancer models including acute lymphoblastic leukemia (ALL) and is under pre-clinical development by the US National Cancer Institute, but no information is available about potential mechanisms of resistance. In a separate report, we showed that intraperitoneal silvestrol is approximately 100% bioavailable systemically, although oral doses were only 1% bioavailable despite an apparent lack of metabolism. To explore mechanisms of silvestrol resistance and the possible role of efflux transporters in silvestrol disposition, we characterized multi-drug resistance transporter expression and function in a silvestrol-resistant ALL cell line generated via culture of the 697 ALL cell line in gradually increasing silvestrol concentrations. This resistant cell line, 697-R, shows significant upregulation of ABCB1 mRNA and P-glycoprotein (Pgp) as well as cross-resistance to known Pgp substrates vincristine and romidepsin. Furthermore, 697-R cells readily efflux the fluorescent Pgp substrate rhodamine 123. This effect is prevented by Pgp inhibitors verapamil and cyclosporin A, as well as siRNA to ABCB1, with concomitant re-sensitization to silvestrol. Together, these data indicate that silvestrol is a substrate of Pgp, a potential obstacle that must be considered in the development of silvestrol for oral delivery or targeting to tumors protected by Pgp overexpression.
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Affiliation(s)
- Sneha V Gupta
- College of Pharmacy, The Ohio State University, Columbus, USA
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Gupta SV, Sass EJ, Davis ME, Edwards RB, Lozanski G, Heerema NA, Lehman A, Zhang X, Jarjoura D, Byrd JC, Chan KK, Kinghorn AD, Grever M, Phelps MA, Lucas DM. Abstract 1721: Resistance to silvestrol is mediated by MDR1/Pgp over-expression in a lymphoblastic leukemia cell line and is reversible by treatment with rapamycin. Cancer Res 2011. [DOI: 10.1158/1538-7445.am2011-1721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
We previously showed that silvestrol, a translation initiation inhibitor, has potent cytotoxic activity in chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (ALL) B-cells in vitro and in vivo (Blood. 2009; 113(19):4656-66). To study potential mechanisms of silvestrol resistance, we generated a silvestrol-resistant B-leukemia cell line as a model system for B-cell leukemias. The 697 ALL cell line was incubated with step-wise increasing concentrations of silvestrol to generate a cell line (697-R) resistant to 80 nM silvestrol. In contrast, the LC50 (concentration lethal to 50%) of silvestrol in the parental 697 cell line is approximately 5 nM. 697-R cells retained genotypic and immunophenotypic features of the parental 697 cell line. One common mechanism of drug resistance in cancer is the over-expression of the multidrug resistance gene ABCB1 and its protein product, multidrug resistance-1/permeability glycoprotein (MDR1/Pgp). Using RT-PCR and flow cytometry, we confirmed increased MDR1 mRNA and protein expression in 697-R cells compared to parental 697 cells. Consistent with MDR1 upregulation, 697-R cells also showed resistance to the MDR1 substrates vincristine and depsipeptide, but not to the non-MDR1 substrate flavopiridol. We next assessed the functional activity of MDR1 in 697-R by measuring efflux of the fluorescent MDR1 substrate rhodamine 123 by flow cytometry. Rhodamine 123 was nearly completely eliminated from 697-R cells within 2 hours, but was fully retained in parental 697 cells. The common MDR1 inhibitors verapamil and cyclosporine inhibited rhodamine efflux from 697-R cells. As this type of multidrug resistance can be mediated by several genes, we used MDR1-specific siRNA to determine whether over-expression of MDR1 is responsible for rhodamine efflux. At 48 hours post-transfection, MDR1 siRNA-transfected cells showed significantly reduced efflux of rhodamine 123 compared to scrambled and irrelevant controls. It has previously been reported that the mTOR inhibitor rapamycin can also block MDR1 function. We therefore tested this using the 697-R cell line.
Similar to verapamil, rapamycin was also able to inhibit the efflux of rhodamine 123 from these cells. Furthermore, rapamycin was also able to restore silvestrol sensitivity to 697-R cells. In conclusion, we show that MDR1/Pgp over-expression is at least one mechanism of silvestrol resistance in cell lines, and known MDR1 inhibitors including rapamycin can reverse this resistance in vitro.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1721. doi:10.1158/1538-7445.AM2011-1721
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Affiliation(s)
| | | | | | | | | | | | - Amy Lehman
- 1The Ohio State University, Columbus, OH
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Rooney TA, Renard DC, Sass EJ, Thomas AP. Oscillatory cytosolic calcium waves independent of stimulated inositol 1,4,5-trisphosphate formation in hepatocytes. J Biol Chem 1991; 266:12272-82. [PMID: 2061312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The mechanisms underlying agonist-induced oscillations in intracellular free calcium ion concentration ([Ca2+]i) in hepatocytes were investigated by utilizing tert-butyl hydroperoxide (TBHP) as a tool to perturb hepatocyte Ca2+ homeostasis independent of receptor activation. In permeabilized hepatocytes, TBHP inhibited Ca2+ uptake into the inositol 1,4,5-trisphosphate (InsP3)-sensitive Ca2+ pool and increased the sensitivity to InsP3 for Ca2+ release. The effects of TBHP could be mimicked by addition of oxidized glutathione (GSSG) and reversed by pretreatment with dithiothreitol. TBHP and GSSG had no effect on the metabolic degradation of [3H]InsP3 in permeabilized cells. The effect of TBHP on [Ca2+]i in intact cells was investigated by digital imaging fluorescence microscopy of Fura-2-loaded primary cultured hepatocytes. TBHP treatment initiated a series of [Ca2+]i oscillations similar to those caused by Ca2(+)-mobilizing hormones. Moreover, in common with the actions of hormones in these cells (Rooney, T.A., Sass, E., and Thomas, A,P. (1990) J. Biol. Chem. 265, 10792-10796), the [Ca2+]i oscillations induced by TBHP propagated through the cell as Ca2+ waves, originating from a discrete subcellular locus identical to that for phenylephrine-induced [Ca2+]i oscillations. The Ca2+ waves induced by TBHP had similar rates of progress (24-27 microns.s-1) to those generated by phenylephrine. Removal of extracellular Ca2+ increased the initial latency of the TBHP responses, but had no effect on the amplitude or rate of propagation of the Ca2+ waves. Addition of TBHP to cells in the presence of phenylephrine converted the oscillatory phenylephrine [Ca2+]i response into a sustained [Ca2+]i increase. The effects of TBHP in intact cells occurred in the absence of any stimulated inositol polyphosphate formation as measured in populations of [3H]inositol-labeled hepatocytes. The data indicate that spatially organized [Ca2+]i oscillations in intact hepatocytes can occur without any requirement for phospholipase C activation. Furthermore, for agents that act by mobilizing Ca2+ from the InsP3-sensitive pool, the kinetics of the Ca2+ release phase of the [Ca2+]i oscillations appears to be independent of the nature of the stimulus.
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Affiliation(s)
- T A Rooney
- Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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Rooney TA, Sass EJ, Thomas AP. Agonist-induced cytosolic calcium oscillations originate from a specific locus in single hepatocytes. J Biol Chem 1990; 265:10792-6. [PMID: 2113061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Digital imaging fluorescence microscopy of fura-2-loaded hepatocytes in primary culture has been used to examine the changes of cytosolic free Ca2+ ([Ca2+]i) in response to receptor activation by alpha 1-adrenergic agonists and vasopressin at the subcellular level. Agonist-induced Ca2+ oscillations did not occur synchronously within the cell but originated from a specific region adjacent to the cell membrane and then propagated throughout the rest of the cell, with each oscillation within a series originating from the same locus. Furthermore, hormones acting through different receptors produced Ca2+ waves with similar rates of progress (20-25 microns.s-1) which originated from the same subcellular locus. For a given cell, the rate of progress and amplitude of the Ca2+ waves were independent of applied agonist concentration and were unaffected by depletion of extracellular Ca2+. The kinetics of Ca2+ increase at different points within the cell indicated that the Ca2+ waves were not driven by diffusion but were characteristic of a self-propagating mechanism. Significantly, when cells were treated with A1F-4 to directly activate the G-protein which couples receptor occupancy to [Ca2+]i mobilization, the origin and kinetics of the Ca2+ waves were identical to those observed with hormonal stimulation. It is proposed that the spatial organization of the intracellular Ca2+ release mechanisms may have significance in the regulation of the asymmetric metabolic functions of hepatocytes and other functionally polarized cells.
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Affiliation(s)
- T A Rooney
- Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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Rooney TA, Sass EJ, Thomas AP. Characterization of cytosolic calcium oscillations induced by phenylephrine and vasopressin in single fura-2-loaded hepatocytes. J Biol Chem 1989; 264:17131-41. [PMID: 2793847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Changes of cytosolic free Ca2+ [( Ca2+]i) in response to receptor activation were studied at the single cell level by using digital imaging fluorescence microscopy of fura-2-loaded primary cultured hepatocytes. In response to phenylephrine and vasopressin, individual hepatocytes displayed dose-dependent oscillations of [Ca2+]i similar to those observed in aequorin-injected hepatocytes by Woods et al. (Woods, N. M., Cuthbertson, K. S. R., and Cobbold, P. H. (1986) Nature 329, 719-721). With increasing agonist concentration, the frequency of oscillations increased and the latent period decreased. For a given cell, peak [Ca2+]i was independent of applied agonist concentration. However, there was considerable variation from cell to cell in the absolute value of peak [Ca2+]i. There was also marked intercellular heterogeneity in the latency, frequency, and overall pattern of the Ca2+ responses. Such asynchronous responses can be explained in part by the apparent differential agonist sensitivity of individual cells for latency and frequency. At high doses, phenylephrine maintained an oscillatory pattern, whereas vasopressin produced a complex mixture of spiking and sustained [Ca2+]i responses. Vasopressin and phenylephrine also displayed differently shaped [Ca2+]i oscillations at submaximal doses, due primarily to a slower rate of decay with vasopressin. Despite the large cell-cell variation in the patterns of [Ca2+]i oscillations, successive readditions of the same agonist elicited identical cell-specific patterns of oscillation. In the absence of extracellular Ca2+ the frequency but not the magnitude of [Ca2+]i oscillations was decreased. Buffering of [Ca2+]i by increasing the fura-2 load of single hepatocytes also decreased the frequency of oscillations without affecting the peak Ca2+ level. These data provide further support for the importance of frequency modulation in agonist-induced Ca2+ responses and suggest that Ca2+ itself plays an important role in regulating the frequency of [Ca2+]i oscillations. Furthermore, the data demonstrate a broad heterogeneity in hepatocyte [Ca2+]i oscillations which may underlie the nonoscillatory responses of cell populations.
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Affiliation(s)
- T A Rooney
- Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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Rooney TA, Sass EJ, Thomas AP. Characterization of Cytosolic Calcium Oscillations Induced by Phenylephrine and Vasopressin in Single Fura-2-loaded Hepatocytes. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)71469-5] [Citation(s) in RCA: 284] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Abstract
The fluorescent Ca2+ indicator fura-2 was used to follow cytosolic Ca2+ transients during excitation-contraction coupling in suspensions of isolated rat heart cells induced to beat synchronously by electrical field stimulation. The Ca2+ transient reached a maximum at about 30 ms after application of the electrical stimulus and then relaxed to the basal level over the following 200 ms. Treatment of the myocytes with 0.25 to 2.0% ethanol (40 to 340 mM) caused a decrease in the peak of the Ca2+ transient, with no apparent change in the time to peak. This effect of ethanol occurred progressively over a period of about 1 min before a new stable state was achieved. At 1% ethanol the peak Ca2+ level was reduced by 50%. Ethanol reversed the stimulatory effect of isoproterenol on peak Ca2+ and at high levels of ethanol the beta-adrenergic agonist no longer caused any enhancement of the Ca2+ transient. Ethanol did not cause any marked change in the basal Ca2+ level between beats. The effects of ethanol were readily reversible. These results suggest that the negative inotropic effect of ethanol observed in intact cardiac muscle preparations may result in part from interference with the Ca2+ fluxes responsible for excitation-contraction coupling in ventricular myocytes.
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Affiliation(s)
- A P Thomas
- Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107
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