151
|
Abstract
The follicular lymphomas are indolent diseases that are highly responsive to various combinations of standard chemotherapy drugs. Nevertheless, until recently, no regimen had improved patient outcome. The incorporation of effective and well-tolerated monoclonal antibodies, such as rituximab, into chemoimmunotherapeutic strategies provided the first evidence that survival of these patients could be prolonged. Nevertheless, follicular lymphoma remains incurable and characterized by recurrent relapses requiring additional treatment. An increasing number of effective drugs are now being evaluated either alone or in combinations including the chemotherapy drugs bendamustine and bortezomib. More targeted agents include monoclonal antibodies and their derivatives such as drug-antibody conjugates and small modular immunopharmaceuticals. Other agents inhibit various cellular pathways including those triggered by the B-cell receptor, including spleen tyrosine kinase (Syk) and Bruton's tyrosine kinase, and other intracellular pathways such as the mammalian target of rapamycin (mTOR), PI3-kinase, and apoptosis, and drugs that target the tumor microenvironment, notably the immunomodulatory agent lenalidomide. The development of combinations of these agents should be based on scientific rationale with correlative studies to enhance our understanding of the mechanisms of action and resistance of the drugs and the biology of the tumor to further improve the outcome of patients with follicular lymphoma.
Collapse
Affiliation(s)
- Bruce D Cheson
- Georgetown University Hospital, Lombardi Comprehensive Cancer Center, 3800 Reservoir Rd NW, Washington, DC 20007, United States.
| |
Collapse
|
152
|
Donato NJ, Peterson LF. Chronic myeloid leukemia stem cells and developing therapies. Leuk Lymphoma 2011; 52 Suppl 1:60-80. [PMID: 21299460 DOI: 10.3109/10428194.2010.546921] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Chronic myeloid leukemia therapy has remarkably improved with the use of frontline BCR-ABL kinase inhibitors such that newly diagnosed patients have minimal disease manifestations or progression. Effective control of disease may also set the stage for eventual 'cure' of this leukemia. However, the existence of Philadelphia chromosome-positive leukemic cells that are unaffected by BCR-ABL inhibition represents a major barrier that may delay or prevent curative therapy with the current approaches. The most commonly reported mechanism of resistance to tyrosine kinase inhibitor-based therapies involves BCR-ABL gene mutations and amplification, but these changes may not be solely responsible for disease relapse when inhibitor-based therapies are curtailed. Therefore new targets may need to be defined before significant advancement in curative therapies is possible. Emerging evidence suggests that persistence of chronic myeloid leukemia stem cells or acquisition of stem cell-like characteristics prevents complete elimination of chronic myeloid leukemia by tyrosine kinase inhibition alone. This review focuses on several recently emerging concepts regarding the existence and characteristics of chronic myeloid leukemia stem cells. Definitions based on human primary cells and animal model studies are highlighted as are the potential signaling pathways associated with disease repopulating cells. Finally, several recently defined therapeutic targets and active compounds that have emerged from stem cell studies are described. Our goal is to provide an unbiased report on the current state of discovery within the chronic myeloid leukemia stem cell field and to orient the reader to emerging therapeutic targets and strategies that may lead to elimination of this leukemia.
Collapse
Affiliation(s)
- Nicholas J Donato
- University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109, USA.
| | | |
Collapse
|
153
|
Brem EA, Thudium K, Khubchandani S, Tsai PC, Olejniczak SH, Bhat S, Riaz W, Gu J, Iqbal A, Campagna R, Knight J, Mavis C, Hoskin P, Deeb G, Gibbs JF, Fetterly G, Czuczman MS, Hernandez-Ilizaliturri FJ. Distinct cellular and therapeutic effects of obatoclax in rituximab-sensitive and -resistant lymphomas. Br J Haematol 2011; 153:599-611. [PMID: 21492126 DOI: 10.1111/j.1365-2141.2011.08669.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bcl-2 proteins represent a rheostat that controls cellular viability. Obatoclax, a BH3-mimetic, has been designed to specifically target and counteract anti-apoptotic Bcl-2 proteins. We evaluated the biological effects of obatoclax on the anti-tumour activity of rituximab and chemotherapy agents. Obatoclax induced cell death of rituximab/chemotherapy-sensitive (RSCL), -resistant cell lines (RRCL) and primary tumour-cells derived from patients with B-cell lymphomas (N=39). Obatoclax also enhanced the activity of rituximab and had synergistic activity when combined with chemotherapy agents. The ability of Obatoclax to induce PARP cleavage varied between patient samples and was not observed in some RRCL. Inhibition of caspase activity did not affect obatoclax activity, suggesting the existence of caspase-independent death pathways. Autophagy was detected by LC3 conversion and/or electron microscopy in RRCL and in patient-derived tumour cells. Moreover, obatoclax activity was inhibited by Beclin-1 knockdown. In summary, obatoclax is an active Bcl-2 inhibitor that potentiates the activity of chemotherapy agents and, to a lesser degree, rituximab. Defining the molecular events triggered by obatoclax is necessary to further its clinical development and identify potential biomarkers that are predictive of response.
Collapse
Affiliation(s)
- Elizabeth A Brem
- Department of Medicine, Roswell Park Cancer Institute,Elm and Carlton Streets, Buffalo, NY 14263, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
154
|
Fallica B, Makin G, Zaman MH. Bioengineering approaches to study multidrug resistance in tumor cells. Integr Biol (Camb) 2011; 3:529-39. [PMID: 21387035 DOI: 10.1039/c0ib00142b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of cancer cells to become resistant to chemotherapeutic agents is a major challenge for the treatment of malignant tumors. Several strategies have emerged to attempt to inhibit chemoresistance, but the fact remains that resistance is a problem for every effective anticancer drug. The first part of this review will focus on the mechanisms of chemoresistance. It is important to understand the environmental cues, transport limitations and the cellular signaling pathways associated with chemoresistance before we can hope to effectively combat it. The second part of this review focuses on the work that needs to be done moving forward. Specifically, this section focuses on the necessity of translational research and interdisciplinary directives. It is critical that the expertise of oncologists, biologists, and engineers be brought together to attempt to tackle the problem. This discussion is from an engineering perspective, as the dialogue between engineers and other cancer researchers is the most challenging due to non-overlapping background knowledge. Chemoresistance is a complex and devastating process, meaning that we urgently need sophisticated methods to study the process of how cells become resistant.
Collapse
Affiliation(s)
- Brian Fallica
- Department of Biomedical Engineering, Boston University, USA
| | | | | |
Collapse
|
155
|
Nabhan C, Dalal N, Mehta J, Kay NE. Biologic agent activity in chronic lymphocytic leukemia: a framework for future therapies. Leuk Lymphoma 2011; 52:374-86. [DOI: 10.3109/10428194.2010.545461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
156
|
Wilson WH, Hernandez-Ilizaliturri FJ, Dunleavy K, Little RF, O'Connor OA. Novel disease targets and management approaches for diffuse large B-cell lymphoma. Leuk Lymphoma 2011; 51 Suppl 1:1-10. [PMID: 20658952 DOI: 10.3109/10428194.2010.500045] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diffuse large B-cell lymphoma (DLBCL) responds well to treatment with CHOP and the R-CHOP regimen, but a subset of patients still fail to achieve complete or durable responses. Recent advances in gene expression profiling have led to the identification of three different subtypes of DLBCL, and confirmed that patients with the activated B-cell (ABC) disease subtype are less likely to respond well to CHOP-based regimens than those with germinal centre B-cell-type (GCB) disease. This discovery could herald the use of gene expression profiling to aid treatment decisions in DLBCL, and help identify the most effective management strategies for patients. Treatment options for patients with relapsed or refractory DLBCL are limited and several novel agents are being developed to address this unmet clinical need. Novel agents developed to treat plasma cell disorders such as multiple myeloma have shown promising activity in patients with NHL. Indeed, the immunomodulatory agent lenalidomide and the proteasome inhibitors bortezomib and carfilzomib, as single agents or in combination with chemotherapy, have already demonstrated promising activity in patients with the ABC subtype of DLBCL. One should not be complacent however when applying these agents to new disease types, because dose and drug scheduling can have marked effects on the responses achieved with investigational agents. As more targeted agents are developed, the timing of administration with other agents in clinical trials will become increasingly important to ensure maximal efficacy while minimizing side effects.
Collapse
Affiliation(s)
- Wyndham H Wilson
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
| | | | | | | | | |
Collapse
|
157
|
Small-molecule inhibitors reveal a new function for Bcl-2 as a proangiogenic signaling molecule. Curr Top Microbiol Immunol 2011; 348:115-37. [PMID: 20941592 PMCID: PMC3812667 DOI: 10.1007/82_2010_109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cancer has a complex etiology and displays a wide range of cellular escape pathways that allow it to circumvent treatment. Signaling molecules functionally downstream of the circumvented pathways, and particularly at checkpoints where several of these pathways intersect, provide valuable targets for the development of novel anti-cancer drugs. Bcl-2, a pro-survival signaling molecule, is one such protein. This review examines the efficacy, potency, and function of several small molecule inhibitor drugs targeted to the Bcl-2 family of proteins. The review focuses on the compounds with most available data within the literature and discusses both the anti-cancer and the recently unveiled anti-angiogenic potential of this new class of drugs.
Collapse
|
158
|
Wilson WH, O'Connor OA, Czuczman MS, LaCasce AS, Gerecitano JF, Leonard JP, Tulpule A, Dunleavy K, Xiong H, Chiu YL, Cui Y, Busman T, Elmore SW, Rosenberg SH, Krivoshik AP, Enschede SH, Humerickhouse RA. Navitoclax, a targeted high-affinity inhibitor of BCL-2, in lymphoid malignancies: a phase 1 dose-escalation study of safety, pharmacokinetics, pharmacodynamics, and antitumour activity. Lancet Oncol 2010; 11:1149-59. [PMID: 21094089 DOI: 10.1016/s1470-2045(10)70261-8] [Citation(s) in RCA: 634] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Proteins of the BCL-2 family regulate clonal selection and survival of lymphocytes, and are frequently overexpressed in lymphomas. Navitoclax is a targeted high-affinity small molecule that inhibits the anti-apoptotic activity of BCL-2 and BCL-XL. We aimed to assess the safety and antitumour activity of navitoclax in patients with lymphoid tumours, and establish the drug's pharmacokinetic and pharmacodynamic profiles. METHODS In this phase 1 dose-escalation study, patients (aged ≥18 years) with relapsed or refractory lymphoid malignancies were enrolled and treated at seven sites in the USA between November, 2006, and November, 2009. A modified Fibonacci 3+3 design was used to assign patients to receive oral navitoclax once daily by one of two dosing schedules: intermittently for the first 14 days of a 21-day cycle (14/21) at doses of 10, 20, 40, 80, 110, 160, 225, 315, or 440 mg/day; or continuously for 21 days of a 21-day cycle (21/21) at doses of 200, 275, 325, or 425 mg/day. Study endpoints were safety, maximum tolerated dose, pharmacokinetic profile, pharmacodynamic effects on platelets and T cells, and antitumour activity. This trial is registered with ClinicalTrials.gov, number NCT00406809. FINDINGS 55 patients were enrolled (median age 59 years, IQR 51-67), 38 to receive the 14/21 dosing schedule, and 17 to receive the 21/21 dosing schedule. Common toxic effects included grade 1 or 2 anaemia (41 patients), infection (39), diarrhoea (31), nausea (29), and fatigue (21); and grade 3 or 4 thrombocytopenia (29), lymphocytopenia (18), and neutropenia (18). On the intermittent 14/21 schedule, dose-limiting toxic effects were hospital admissions for bronchitis (one) and pleural effusion (one), grade 3 increase in aminotransferases (one), grade 4 thrombocytopenia (one), and grade 3 cardiac arrhythmia (one). To reduce platelet nadir associated with intermittent 14/21 dosing, we assessed a 150 mg/day lead-in dose followed by a continuous 21/21 dosing schedule. On the 21/21 dosing schedule, two patients did not complete the first cycle and were excluded from assessment of dose-limiting toxic effects; dose-limiting toxic effects were grade 4 thrombocytopenia (one), grade 3 increase in aminotransferases (one), and grade 3 gastrointestinal bleeding (one). Navitoclax showed a pharmacodynamic effect on circulating platelets and T cells. Clinical responses occurred across the range of doses and in several tumour types. Ten of 46 patients with assessable disease had a partial response, and these responders had median progression-free survival of 455 days (IQR 40-218). INTERPRETATION Navitoclax has a novel mechanism of peripheral thrombocytopenia and T-cell lymphopenia, attributable to high-affinity inhibition of BCL-XL and BCL-2, respectively. On the basis of these findings, a 150 mg 7-day lead-in dose followed by a 325 mg dose administered on a continuous 21/21 dosing schedule was selected for phase 2 study. FUNDING Abbott Laboratories, Genentech, and National Cancer Institute, National Institutes of Health.
Collapse
Affiliation(s)
- Wyndham H Wilson
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
159
|
Vizirianakis IS, Chatzopoulou M, Bonovolias ID, Nicolaou I, Demopoulos VJ, Tsiftsoglou AS. Toward the development of innovative bifunctional agents to induce differentiation and to promote apoptosis in leukemia: clinical candidates and perspectives. J Med Chem 2010; 53:6779-810. [PMID: 20925433 DOI: 10.1021/jm100189a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Ioannis S Vizirianakis
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences,Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
| | | | | | | | | | | |
Collapse
|
160
|
Fulda S. Exploiting mitochondrial apoptosis for the treatment of cancer. Mitochondrion 2010; 10:598-603. [DOI: 10.1016/j.mito.2010.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/10/2010] [Accepted: 05/12/2010] [Indexed: 01/11/2023]
|
161
|
Schnaiter A, Stilgenbauer S. Refractory chronic lymphocytic leukemia--new therapeutic strategies. Oncotarget 2010; 1:472-482. [PMID: 21317446 PMCID: PMC3248129 DOI: 10.18632/oncotarget.184] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 11/18/2010] [Indexed: 11/25/2022] Open
Abstract
Treatment outcome of chronic lymphocytic leukemia (CLL) has considerably improved since the introduction of fludarabine (F) as part of the standard therapy. Nevertheless, refractoriness to fludarabine occurs in a significant number of patients and is associated with an unfavorable prognosis. Important risk factors are 17p deletion and/or mutation of TP53. For this subgroup the CD52 antibody alemtuzumab (A) presents a new treatment approach and has already been approved. Meanwhile we have to face also refractoriness to alemtuzumab. Importantly, the monoclonal CD20 antibody ofatumumab has now shown efficacy in F and A double-refractory CLL. The next generation CD20 antibody GA-101 is currently compared to rituximab (R) and will possibly be its more potent successor. Further B-cell antigens are targeted by lumiliximab (CD23), TRU-016 (CD37) and blinatumomab (CD19). Apart from monoclonal antibody therapies, a great number of small molecules are examined for the treatment of refractory and relapsed CLL. Most of these agents aim to overcome apoptosis resistance in CLL cells or influence the microenvironment. Typical targets are regulators of the cell cycle and antiapoptotic molecules like the members of the Bcl-2 family. Up to now the most promising agents appear to be flavopiridol and lenalidomide among others.
Collapse
MESH Headings
- Antibodies, Monoclonal/therapeutic use
- Antineoplastic Agents/therapeutic use
- Drug Resistance, Neoplasm/drug effects
- Histone Deacetylase Inhibitors/therapeutic use
- Humans
- Immunotherapy/methods
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/mortality
- Leukemia, Lymphocytic, Chronic, B-Cell/therapy
- Recurrence
- Survival Analysis
- Therapies, Investigational/methods
- Therapies, Investigational/trends
- Vidarabine/analogs & derivatives
- Vidarabine/therapeutic use
Collapse
|
162
|
Wierda WG, Chiorazzi N, Dearden C, Brown JR, Montserrat E, Shpall E, Stilgenbauer S, Muneer S, Grever M. Chronic lymphocytic leukemia: new concepts for future therapy. CLINICAL LYMPHOMA, MYELOMA & LEUKEMIA 2010; 10:369-78. [PMID: 21030350 DOI: 10.3816/clml.2010.n.070] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Over the past several years, we have witnessed rapid advances in our understanding of the biology and treatment of chronic lymphocytic leukemia (CLL). New prognostic factors have been characterized that help identify patients at high risk of rapid disease progression, refractoriness to treatment, and short overall survival (OS). These advances have led to a significant paradigm shift in the management of CLL. Novel therapeutic strategies, including combinations of monoclonal antibodies with conventional chemotherapy, have dramatically improved response rates, remission duration, and recently, OS. However, these benefits do not appear to extend to certain patient subsets, especially those with unfavorable clinical or cytogenetic risk factors. The majority of patients with CLL will invariably relapse following first-line therapy and can acquire high-risk genetic abnormalities. Repeated treatment leads to eventual therapeutic refractoriness and shortened survival compared with age-matched healthy individuals. Several novel agents and strategies, including next-generation anti-CD20 monoclonal antibodies, the alkylating agent bendamustine, the immunomodulatory agent lenalidomide, the cyclin-dependent kinase inhibitor flavopiridol, and small-molecule Bcl2 inhibitors, are currently under clinical investigation as novel agents that will hopefully improve treatment outcomes for CLL. Though allogeneic stem cell transplantation offers curative potential, it also presents clinical challenges in terms of patient appropriateness, donor availability, and timing. The merits and challenges of incorporating these treatment modalities into the treatment algorithm for patients with CLL, as discussed by a panel of experts in CLL, are outlined in this article.
Collapse
Affiliation(s)
- William G Wierda
- University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
163
|
Speirs CK, Hwang M, Kim S, Li W, Chang S, Varki V, Mitchell L, Schleicher S, Lu B. Harnessing the cell death pathway for targeted cancer treatment. Am J Cancer Res 2010; 1:43-61. [PMID: 21969218 PMCID: PMC3180107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 09/29/2010] [Indexed: 05/31/2023] Open
Abstract
Genotoxic agents have long targeted apoptotic cell death as a primary means of treating cancer. However, the presence of cellular defects in many cancers has contributed to an acquired resistance to apoptotic cell death, lowering the effectiveness of chemo- and radiotherapies. The mechanisms by which cells achieve this resistance to treatment are still being investigated, but an alternative approach is the study of cell death pathways that are mechanistically distinct from apoptosis. These pathways, including autophagy and necrosis, have arisen as attractive targets for cancer therapy. This review will discuss apoptosis, autophagy, and necrosis in the context of tumorigenesis and drug resistance, as well as provide an up-to-date preclinical and clinical review of inhibitors targeting these cell death pathways for multiple cancer types. The goal of these studies is to identify molecular targets that will enhance the efficacy and specificity of current cancer therapies.
Collapse
Affiliation(s)
- Christina K Speirs
- Department of Radiation Oncology, Vanderbilt University School of Medicine, Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center Nashville Tennessee, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
164
|
Kfir-Erenfeld S, Sionov RV, Spokoini R, Cohen O, Yefenof E. Protein kinase networks regulating glucocorticoid-induced apoptosis of hematopoietic cancer cells: fundamental aspects and practical considerations. Leuk Lymphoma 2010; 51:1968-2005. [PMID: 20849387 DOI: 10.3109/10428194.2010.506570] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glucocorticoids (GCs) are integral components in the treatment protocols of acute lymphoblastic leukemia, multiple myeloma, and non-Hodgkin lymphoma owing to their ability to induce apoptosis of these malignant cells. Resistance to GC therapy is associated with poor prognosis. Although they have been used in clinics for decades, the signal transduction pathways involved in GC-induced apoptosis have only partly been resolved. Accumulating evidence shows that this cell death process is mediated by a communication between nuclear GR affecting gene transcription of pro-apoptotic genes such as Bim, mitochondrial GR affecting the physiology of the mitochondria, and the protein kinase glycogen synthase kinase-3 (GSK3), which interacts with Bim following exposure to GCs. Prevention of Bim up-regulation, mitochondrial GR translocation, and/or GSK3 activation are common causes leading to GC therapy failure. Various protein kinases positively regulating the pro-survival Src-PI3K-Akt-mTOR and Raf-Ras-MEK-ERK signal cascades have been shown to be activated in malignant leukemic cells and antagonize GC-induced apoptosis by inhibiting GSK3 activation and Bim expression. Targeting these protein kinases has proven effective in sensitizing GR-positive malignant lymphoid cells to GC-induced apoptosis. Thus, intervening with the pro-survival kinase network in GC-resistant cells should be a good means of improving GC therapy of hematopoietic malignancies.
Collapse
Affiliation(s)
- Shlomit Kfir-Erenfeld
- The Lautenberg Center of Immunology and Cancer Research, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | | | | | | | | |
Collapse
|
165
|
GX15-070 (obatoclax) overcomes glucocorticoid resistance in acute lymphoblastic leukemia through induction of apoptosis and autophagy. Cell Death Dis 2010; 1:e76. [PMID: 21364679 PMCID: PMC3032343 DOI: 10.1038/cddis.2010.53] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glucocorticoids (GCs) are common components of many chemotherapeutic regimens for lymphoid malignancies including acute lymphoblastic leukemia (ALL). The BCL-2 family has an essential role in regulating GC-induced cell death. Here we show that downregulation of antiapoptotic BCL-2 family proteins, especially MCL-1, enhances GC-induced cell death. Thus we target MCL-1 by using GX15-070 (obatoclax) in ALL cells. Treatment with GX15-070 in both dexamethasone (Dex)-sensitive and -resistant ALL cells shows effective growth inhibition and cell death. GX15-070 induces caspase-3 cleavage and increases the Annexin V-positive population, which is indicative of apoptosis. Before the onset of apoptosis, GX15-070 induces LC3 conversion as well as p62 degradation, both of which are autophagic cell death markers. A pro-apoptotic molecule BAK is released from the BAK/MCL-1 complex following GX15-070 treatment. Consistently, downregulation of BAK reduces caspase-3 cleavage and cell death, but does not alter LC3 conversion. In contrast, downregulation of ATG5, an autophagy regulator, decreases LC3 conversion and cell death, but does not alter caspase-3 cleavage, suggesting that apoptosis and autophagy induced by GX15-070 are independently regulated. Downregulation of Beclin-1, which is capable of crosstalk between apoptosis and autophagy, affects GX15-070-induced cell death through apoptosis but not autophagy. Taken together, GX15-070 treatment in ALL could be an alternative regimen to overcome glucocorticoid resistance by inducing BAK-dependent apoptosis and ATG5-dependent autophagy.
Collapse
|
166
|
Farsaci B, Sabzevari H, Higgins JP, Di Bari MG, Takai S, Schlom J, Hodge JW. Effect of a small molecule BCL-2 inhibitor on immune function and use with a recombinant vaccine. Int J Cancer 2010; 127:1603-13. [PMID: 20091862 DOI: 10.1002/ijc.25177] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Small molecule BCL-2 inhibitors are being examined as monotherapy in phase I/II clinical trials for several types of tumors. However, few data are available about the effect of BCL-2 inhibitors on immune function. The aims of our study were to investigate the effect of a small molecule BCL-2 inhibitor on immune function and determine the most effective way of combining this inhibitor with a recombinant vaccine to treat tumors. The in vitro effect of the pan-BCL-2 inhibitor GX15-070 was assessed in mouse CD8 T lymphocytes at 2 different stages of activation as well as regulatory T lymphocytes (Treg). The in vivo effect of GX15-070 after recombinant vaccinia/fowlpox CEA-TRICOM vaccination was analyzed in tumor-infiltrating lymphocytes, and in splenocytes of mice bearing subcutaneous tumors. The therapeutic efficacy of such sequential therapy was measured as a reduction of pulmonary tumor nodules. Activated mature CD8 T lymphocytes were more resistant to GX15-070 as compared to early-activated cells. Treg function was significantly decreased after treatment with the BCL-2 inhibitor. In vivo, GX15-070 was given after vaccination so as to not negatively impact the induction of vaccine-mediated immunity, resulting in increased intratumoral activated CD8:Treg ratio and significant reduction of pulmonary tumor nodules. Our study is the first to show the effect of a small molecule BCL-2 inhibitor on the immune system and following a vaccine. It is also the first to demonstrate the efficacy of this sequence in reducing tumors in mouse models, providing a rationale for the design of combinational clinical studies.
Collapse
Affiliation(s)
- Benedetto Farsaci
- Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | | | | | |
Collapse
|
167
|
Abstract
Inhibiting apoptosis is widely accepted as a necessary step in the transition from normal to cancer cells, and most cancer therapies exert their effects by indirectly reversing this process. Commitment to apoptosis is caused by permeabilisation of the outer mitochondrial membrane – a process regulated by the binding between different members of the Bcl-2 family. Furthermore, Bcl-2 family members also bind to the endoplasmic reticulum, where they modify processes such as the unfolded-protein response and autophagy that also cause or modify different types of cell death. With the growing understanding of the importance of the Bcl-2 family as crucial regulators of the decision to initiate apoptosis, much effort has been directed at developing small molecules that modify function by directly binding to Bcl-2 proteins. Preclinical experiments have confirmed that these agents kill cancer cells and overcome chemotherapy resistance. Two of these drugs are in the initial stages of clinical development (ABT-263 and obatoclax), and early results show clinical efficacy at tolerable doses. Important questions for the future include the role of these drugs as monotherapy versus combination therapy with other anticancer drugs, and the related issue of the relative toxicity to cancerous versus normal cells.
Collapse
|
168
|
Chen LS, Balakrishnan K, Gandhi V. Inflammation and survival pathways: chronic lymphocytic leukemia as a model system. Biochem Pharmacol 2010; 80:1936-45. [PMID: 20696142 DOI: 10.1016/j.bcp.2010.07.039] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/22/2010] [Accepted: 07/27/2010] [Indexed: 10/19/2022]
Abstract
A primary response to inflammation is an increased survival of the target cell. Several pathways have been identified that promote maintenance of the cell. The principal mechanism for the extended survival is through induction of anti-apoptotic Bcl-2 family proteins. Bcl-2 was the founding member of this family with five additional members, Bcl-X(L), Bcl-W, Bcl-B, Bfl-1, and Mcl-1, discovered mostly in hematological malignancies. Another mechanism that could add to cell survival is the Pim kinase pathway. This family of enzymes is associated with Myc-driven transcription, cell cycle regulation, degradation of pro-apoptotic proteins, and protein translation. Chronic lymphocytic leukemia serves as an optimal model to understand the mechanism by which these two protein families provide survival advantage to cells. In addition, since this malignancy is known to be maintained by microenvironment milieu, this further adds advantage to investigate mechanisms by which these pro-survival proteins are induced in the presence of stromal support. Multiple mechanisms exists that result in increase in transcript and protein level of anti-apoptotic Bcl-2 family members. Following these inductions, post-translational modifications occur resulting in increased stability of pro-survival proteins, while Pim-mediated phosphorylation inhibits pro-apoptotic protein activity. Furthermore, there is a cross-talk between these two (Bcl-2 family proteins and Pim family proteins) pathways that co-operate with each other for CLL cell survival and maintenance. Vigorous efforts are being made to create small molecules that affect these proteins directly or indirectly. Several of these pharmacological inhibitors are in early clinical trials for patients with hematological malignancies.
Collapse
Affiliation(s)
- Lisa S Chen
- Department of Experimental Therapeutics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4095, USA
| | | | | |
Collapse
|
169
|
Parikh SA, Kantarjian H, Schimmer A, Walsh W, Asatiani E, El-Shami K, Winton E, Verstovsek S. Phase II study of obatoclax mesylate (GX15-070), a small-molecule BCL-2 family antagonist, for patients with myelofibrosis. CLINICAL LYMPHOMA, MYELOMA & LEUKEMIA 2010; 10:285-9. [PMID: 20709666 DOI: 10.3816/clml.2010.n.059] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Myelofibrosis (MF) is a disease characterized by the overexpression of the antiapoptotic BCL-2 family of proteins (eg, BCL-XL and MCL-1). PATIENTS AND METHODS We conducted a multicenter, open-label, noncomparative phase II study of obatoclax mesylate, a small-molecule pan-BCL-2 antagonist, in patients with MF. Obatoclax was administered as a 24-hour infusion (on an outpatient basis) every 2 weeks at a fixed dose of 60 mg. RESULTS A total of 22 patients were enrolled, with a median age of 63 years (range, 43-89 years). Twelve were men, and all 22 patients were previously treated (median of 2 previous therapies). Ten patients (45%) had a Lille score of 1, and 9 patients (41%) had a Lille score of 2. Thirteen (59%) were red blood cell transfusion dependent. A median of 7 cycles of obatoclax were administered. No patient achieved complete or partial response according to International Working Group criteria. One patient (4%) demonstrated a clinical improvement (in terms of hemoglobin and platelet count) after 7 cycles of therapy. The improvement was sustained for 4 cycles of therapy, after which he underwent allogeneic stem cell transplantation. The most common adverse events included low-grade ataxia and fatigue in 50% of the patients. Dose reduction because of toxicity was required in 1 patient, whereas 2 patients were taken off the study because of grade 3 ataxia and grade 3 heart failure. Grade 3/4 anemia and thrombocytopenia were evident in 6 (27%) and 4 (18%) patients, respectively. CONCLUSION Obatoclax exhibits no significant clinical activity in patients with MF at the dose and schedule evaluated.
Collapse
Affiliation(s)
- Sameer A Parikh
- Department of Leukemia, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | | | | | | | | | | | | | | |
Collapse
|
170
|
Alyea EP, DeAngelo DJ, Moldrem J, Pagel JM, Przepiorka D, Sadelin M, Young JW, Giralt S, Bishop M, Riddell S. NCI First International Workshop on The Biology, Prevention and Treatment of Relapse after Allogeneic Hematopoietic Cell Transplantation: report from the committee on prevention of relapse following allogeneic cell transplantation for hematologic malignancies. Biol Blood Marrow Transplant 2010; 16:1037-69. [PMID: 20580849 PMCID: PMC3235046 DOI: 10.1016/j.bbmt.2010.05.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2010] [Accepted: 05/14/2010] [Indexed: 10/19/2022]
Abstract
Prevention of relapse after allogeneic hematopoietic stem cell transplantation is the most likely approach to improve survival of patients treated for hematologic malignancies. Herein we review the limits of currently available transplant therapies and the innovative strategies being developed to overcome resistance to therapy or to fill therapeutic modalities not currently available. These novel strategies include nonimmunologic therapies, such as targeted preparative regimens and posttransplant drug therapy, as well as immunologic interventions, including graft engineering, donor lymphocyte infusions, T cell engineering, vaccination, and dendritic cell-based approaches. Several aspects of the biology of the malignant cells as well as the host have been identified that obviate success of even these newer strategies. To maximize the potential for success, we recommend pursuing research to develop additional targeted therapies to be used in the preparative regimen or as maintenance posttransplant, better characterize the T cell and dendritic cells subsets involved in graft-versus-host disease and the graft-versus-leukemia/tumor effect, identify strategies for timing immunologic or nonimmunologic therapies to eliminate the noncycling cancer stem cell, identify more targets for immunotherapies, develop new vaccines that will not be limited by HLA, and develop methods to identify populations at very high risk for relapse to accelerate clinical development and avoid toxicity in patients not at risk for relapse.
Collapse
Affiliation(s)
- Edwin P Alyea
- Dana Farber Cancer Institute, Boston, Massachusetts 02115, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
171
|
Pan J, Cheng C, Verstovsek S, Chen Q, Jin Y, Cao Q. The BH3-mimetic GX15-070 induces autophagy, potentiates the cytotoxicity of carboplatin and 5-fluorouracil in esophageal carcinoma cells. Cancer Lett 2010; 293:167-74. [PMID: 20153924 DOI: 10.1016/j.canlet.2010.01.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 12/25/2009] [Accepted: 01/11/2010] [Indexed: 02/03/2023]
Abstract
Despite improvements in both surgical techniques and radio- and chemo-therapy regimens, the prognosis of esophageal cancer is poor. In pursuit of novel effective strategy, this study examined the effect of the BH3-mimetic GX15-070 on esophageal carcinoma cells. We discovered that GX15-070 inhibited the growth of esophageal cancer cells. There was synergism between GX15-070 and carboplatin or 5-fluorouracil. GX15-070 induced autophagy in esophagus cancer cell line EC9706 and osteosarcoma cancer cell line U2OS. 3-methyladenine and chloroquine, inhibitors of autophagy with distinct mechanisms, potentiated the cytotoxicity of GX15-070. In conclusion, GX15-070 inhibits growth of esophageal cancer cells.
Collapse
Affiliation(s)
- Jingxuan Pan
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
172
|
Duvall CL, Convertine AJ, Benoit DSW, Hoffman AS, Stayton PS. Intracellular delivery of a proapoptotic peptide via conjugation to a RAFT synthesized endosomolytic polymer. Mol Pharm 2010; 7:468-76. [PMID: 19968323 DOI: 10.1021/mp9002267] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Peptides derived from the third B-cell lymphoma 2 (Bcl-2) homology domain (BH3) can heterodimerize with antiapoptotic Bcl-2 family members to block their activity and trigger apoptosis. Use of these peptides presents a viable anticancer approach, but delivery barriers limit the broad application of intracellular-acting peptides as clinical therapeutics. Here, a novel diblock copolymer carrier is described that confers desirable pharmaceutical properties to intracellular-acting therapeutic peptides through site-specific molecular conjugation. This polymer was prepared using reversible addition-fragmentation chain transfer (RAFT) to form a pyridyl disulfide end-functionalized, modular diblock copolymer with precisely controlled molecular weight (M(n)) and low polydispersity (PDI). The diblock polymer (M(n) 19,000 g/mol, PDI 1.27) was composed of an N-(2-hydroxypropyl) methacrylamide (HPMA) first block (M(n) 13,800 g/mol, PDI 1.13) intended to enhance water solubility and circulation time. The second polymer block was a pH-responsive composition designed to enhance endosomal escape and consisted of equimolar quantities of dimethylaminoethyl methacrylate (DMAEMA), propylacrylic acid (PAA), and butyl methacrylate (BMA). A hemolysis assay indicated that the diblock polymer undergoes a physiologically relevant pH-dependent switch from a membrane inert (1% hemolysis, pH 7.4) to a membrane disruptive (61% hemolysis, pH 5.8) conformation. Thiol-disulfide exchange reactions were found to efficiently produce reversible polymer conjugates (75 mol % peptide reactivity with polymer) with a cell-internalized proapoptotic peptide. Microscopy studies showed that peptide delivered via polymer conjugates effectively escaped endosomes and achieved diffusion into the cytosol. Peptide-polymer conjugates also produced significantly increased apoptotic activity over peptide alone in HeLa cervical carcinoma cells as found using flow cytometric measurements of mitochondrial membrane depolarization (2.5-fold increase) and cell viability tests that showed 50% cytotoxicity after 6 h of treatment with 10 muM peptide conjugate. These results indicate that this multifunctional carrier shows significant promise for proapoptotic peptide cancer therapeutics and also as a general platform for delivery of peptide drugs with intracellular targets.
Collapse
Affiliation(s)
- Craig L Duvall
- Department of Bioengineering, University of Washington, Seattle Washington 98195, USA
| | | | | | | | | |
Collapse
|
173
|
Bazargan A, Tam CS. New angles of attack in the fight against chronic lymphocytic leukemia: the advent of novel non-chemotherapeutic agents. Leuk Lymphoma 2010; 51:1596-611. [DOI: 10.3109/10428194.2010.497885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
174
|
Hwang JJ, Kuruvilla J, Mendelson D, Pishvaian MJ, Deeken JF, Siu LL, Berger MS, Viallet J, Marshall JL. Phase I dose finding studies of obatoclax (GX15-070), a small molecule pan-BCL-2 family antagonist, in patients with advanced solid tumors or lymphoma. Clin Cancer Res 2010; 16:4038-45. [PMID: 20538761 DOI: 10.1158/1078-0432.ccr-10-0822] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Two phase I, single-agent studies were conducted to determine the dose and regimen of obatoclax, an antagonist of all BCL-2 antiapoptotic proteins, for evaluation in phase II trials. The two studies, GX001 and GX005, evaluated the safety and tolerability of weekly 1-hour and 3-hour infusions of obatoclax, respectively. EXPERIMENTAL DESIGN Eligible patients in both studies were adults with solid tumor or lymphoma and performance status 0-1 for whom standard therapies were not appropriate. In the GX001 study an accelerated dose titration design was initially used with subsequent cohorts of three to six patients with 40% dose increments between levels. In the GX005 study three to six patients entered at each dose level with 40% dose increments between levels. RESULTS Thirty-five patients were enrolled in studies GX001 (n = 8) and GX005 (n = 27). Clinically significant central nervous system (CNS) toxicity was observed using the 1-hour infusion schedule. The obatoclax maximum tolerated dose (MTD) in GX001 was 1.25 mg/m(2) due to these infusional CNS events. The 3-hour infusion schedule studied in GX005 had improved tolerability, and the obatoclax MTD was 20 mg/m(2). One patient in GX005 with relapsed non-Hodgkin's lymphoma achieved partial response of 2 months' duration, and one patient with relapsed non-Hodgkin's lymphoma had stable disease for 18 months. CONCLUSIONS The 1-hour infusion schedule of obatoclax was associated with neuropsychiatric dose-limiting toxicities at relatively low doses (MTD, 1.25 mg/m(2)). The 3-hour i.v. infusion of obatoclax administered once weekly to patients with solid tumors was better tolerated (MTD, 20 mg/m(2)), and evidence of clinical activity was observed.
Collapse
Affiliation(s)
- Jimmy J Hwang
- Lombardi Cancer Center, Georgetown Medical Center, 3800 Reservoir Road NW, Washington, DC 20007-2113, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
175
|
Wei Y, Kadia T, Tong W, Zhang M, Jia Y, Yang H, Hu Y, Tambaro FP, Viallet J, O'Brien S, Garcia-Manero G. The combination of a histone deacetylase inhibitor with the Bcl-2 homology domain-3 mimetic GX15-070 has synergistic antileukemia activity by activating both apoptosis and autophagy. Clin Cancer Res 2010; 16:3923-32. [PMID: 20538760 DOI: 10.1158/1078-0432.ccr-10-0032] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Single-agent histone deacetylase inhibitors (HDACi) have limited clinical activity in human leukemia. Although the way HDACi exert their antileukemia effect is not fully understood, it is accepted that induction of apoptosis is important. We hypothesized, therefore, that combination of an HDACi with a proapoptotic agent, such as the Bcl-2 homology domain-3 mimetic GX15-070, could result in enhanced antileukemia activity. EXPERIMENTAL DESIGN We analyzed the cellular and molecular effects of two different HDACi (MGCD0103 and vorinostat) in combination with GX15-070 in leukemia cell lines and primary acute myelogenous leukemia cells. RESULTS We showed that the combination had synergistic antileukemia effect both in leukemia cell lines and in primary acute myelogenous leukemia cells. Using molecular markers and electron microscopy, we observed that in addition to apoptosis, autophagy accounts for the nonapoptotic decrease in cell viability, an effect that could be inhibited by chloroquine, an inhibitor of autophagy. Finally, we established a role for calpain activity in the induction of both autophagy and apoptosis by this combination. CONCLUSIONS The combination of an HDACi and GX15-070 has synergistic antileukemia activity, and the effect is mediated by induction of apoptosis and autophagy. The combination should be studied in clinical trials of leukemia and the role of autophagy in leukemia therapy needs to be better understood.
Collapse
Affiliation(s)
- Yue Wei
- Department of Leukemia, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
176
|
Hockenbery DM. Targeting mitochondria for cancer therapy. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:476-489. [PMID: 20213841 DOI: 10.1002/em.20552] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Several recent insights into the roles of mitochondria in cancer have renewed efforts to develop nongenotoxic therapies targeting mitochondrial proteins and functions. Mitochondria are central hubs for intrinsic apoptotic pathways that are activated by cellular stress and injury, and as a consequence, cancers often have defects in these pathways. Bcl-2, the first identified regulator of apoptotic cell deaths, was discovered as an oncogene in human cancers. BCL-2 inhibits mitochondrial pathways of apoptosis through local effects at mitochondrial and endoplasmic reticulum membranes. Increased expression of BCL-2 and the related antiapoptotic proteins BCL-X(L), MCL-1, and BCL-W occurs in significant subsets of common cancer types (Table I) and is generally correlated with poor response. Although incomplete, the emerging understanding of BCL-2 functions through structural, biochemical, and organelle physiology studies has provided paths for targeting BCL-2 with small molecules. Cancer cells also exhibit metabolic differences with their normal cell counterparts, including aerobic glycolysis, known as the Warburg effect, mitochondrial membrane hyperpolarization, and unusual dependence on nutrient substrates such as glucose and glutamine. This knowledge has prompted reexamination of the potential cancer selectivity of previously identified mitochondriotoxic compounds, including approved drugs for other indications, and screening programs to identify new compounds with mitochondrial activities.
Collapse
|
177
|
Abstract
Mitochondria are the cells' powerhouse, but also their suicidal weapon store. Dozens of lethal signal transduction pathways converge on mitochondria to cause the permeabilization of the mitochondrial outer membrane, leading to the cytosolic release of pro-apoptotic proteins and to the impairment of the bioenergetic functions of mitochondria. The mitochondrial metabolism of cancer cells is deregulated owing to the use of glycolytic intermediates, which are normally destined for oxidative phosphorylation, in anabolic reactions. Activation of the cell death machinery in cancer cells by inhibiting tumour-specific alterations of the mitochondrial metabolism or by stimulating mitochondrial membrane permeabilization could therefore be promising therapeutic approaches.
Collapse
Affiliation(s)
- Simone Fulda
- University Children's Hospital, Ulm University, Eythstrasse 24, D-89075 Ulm, Germany.
| | | | | |
Collapse
|
178
|
Robak T. Application of new drugs in chronic lymphocytic leukemia. Mediterr J Hematol Infect Dis 2010; 2:e2010011. [PMID: 21415964 PMCID: PMC3033144 DOI: 10.4084/mjhid.2010.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 04/26/2010] [Indexed: 11/08/2022] Open
Abstract
Over the last few years, several new agents have been under evaluation in preclinical studies as well as in early clinical trials, and have shown promise in treating CLL. These treatments include new monoclonal antibodies (mAbs), immunomodulating agents, novel purine nucleoside analogs, Bcl-2 inhibitors and other agents. The most promising are a new mAbs targeted CD20 molecule or CD23, anti-CD40 mAbs and anti-CD37 antibody. Oblimersen, flavopiridol, and lenalidomide are also being evaluated both in pre-clinical studies and in early clinical trials. However, available therapies are only partially efficient and there is an obvious need to develop better strategies and new, more specific and active drugs.
Collapse
Affiliation(s)
- Tadeusz Robak
- Department of Hematology, Medical University of Lodz and Copernicus Memorial Hospital, Lodz, Poland
| |
Collapse
|
179
|
Abstract
Chronic lymphocytic leukaemia (CLL) is the most common adult leukaemia in Europe and North America. The disease is characterized by proliferation and accumulation of small CD5+ B cells in blood, lymph nodes, spleen, liver and bone marrow. The natural clinical course of CLL is highly variable, and chemotherapy is usually not indicated in early and stable disease. However, patients with progressive and more advanced CLL require treatment. For many years, chlorambucil with or without corticosteroids was used in previously untreated patients with CLL. More recently, purine nucleoside analogues (PNAs) [fludarabine, cladribine and pentostatin] have been included in treatment approaches for this disease, and chlorambucil is no longer the leading standard everywhere. Currently, this drug is rather recommended for the treatment of older, unfit patients with co-morbidities, especially in European countries. Significantly higher overall response (OR) and complete response (CR) rates in patients treated initially with PNAs than in those treated with chlorambucil or cyclophosphamide-based combination regimens have been confirmed in randomized, prospective, multicentre trials. Moreover, PNAs administered in combination with cyclophosphamide produce higher response rates, including CR and molecular CR, compared with PNA as monotherapy. Recent reports suggest that the administration of monoclonal antibodies (mAbs) can significantly improve the course of CLL. At present, two mAbs have the most important clinical value in patients with CLL. The first is rituximab, a human mouse antibody that targets CD20 antigens, and the second is alemtuzumab, a humanized form of a rat antibody active against CD52. Several recent reports suggest that in patients with CLL, rituximab combined with a PNA can increase the OR and CR rates compared with PNA or rituximab alone, with acceptable toxicity. In randomized trials, the combination of rituximab with fludarabine and cyclophosphamide (FC-R regimen) demonstrated higher rates of OR, CR and progression-free survival in patients with previously untreated and relapsed or refractory CLL than fludarabine plus cyclophosphamide (FC regimen). Several reports have confirmed significant activity with alemtuzumab in relapsed or refractory CLL, as well as in previously untreated patients. Recently, several new agents have been investigated and have shown promise in treating patients with CLL. These treatments include new mAbs, agents targeting the antiapoptotic bcl-2 family of proteins and receptors involved in mediating survival signals from the microenvironment, antisense oligonucleotides and other agents. The most promising are new mAbs directed against the CD20 molecule, lumiliximab and anti-CD40 mAbs. Oblimersen, alvocidib (flavopiridol) and lenalidomide are also being evaluated both in preclinical studies and in early clinical trials. In recent years, a significant improvement in haematopoietic stem cell transplantation (HSCT) procedures in patients with high-risk CLL has been observed. However, the exact role of HSCT, autologous or allogeneic, in the standard management of CLL patients is still undefined.
Collapse
Affiliation(s)
- Tadeusz Robak
- Department of Hematology, Medical University of Lode, Copernicus Memorial Hospital, Lodz, Poland.
| | | | | |
Collapse
|
180
|
Bonapace L, Bornhauser BC, Schmitz M, Cario G, Ziegler U, Niggli FK, Schäfer BW, Schrappe M, Stanulla M, Bourquin JP. Induction of autophagy-dependent necroptosis is required for childhood acute lymphoblastic leukemia cells to overcome glucocorticoid resistance. J Clin Invest 2010; 120:1310-23. [PMID: 20200450 DOI: 10.1172/jci39987] [Citation(s) in RCA: 248] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 01/06/2010] [Indexed: 12/26/2022] Open
Abstract
In vivo resistance to first-line chemotherapy, including to glucocorticoids, is a strong predictor of poor outcome in children with acute lymphoblastic leukemia (ALL). Modulation of cell death regulators represents an attractive strategy for subverting such drug resistance. Here we report complete resensitization of multidrug-resistant childhood ALL cells to glucocorticoids and other cytotoxic agents with subcytotoxic concentrations of obatoclax, a putative antagonist of BCL-2 family members. The reversal of glucocorticoid resistance occurred through rapid activation of autophagy-dependent necroptosis, which bypassed the block in mitochondrial apoptosis. This effect was associated with dissociation of the autophagy inducer beclin-1 from the antiapoptotic BCL-2 family member myeloid cell leukemia sequence 1 (MCL-1) and with a marked decrease in mammalian target of rapamycin (mTOR) activity. Consistent with a protective role for mTOR in glucocorticoid resistance in childhood ALL, combination of rapamycin with the glucocorticoid dexamethasone triggered autophagy-dependent cell death, with characteristic features of necroptosis. Execution of cell death, but not induction of autophagy, was strictly dependent on expression of receptor-interacting protein (RIP-1) kinase and cylindromatosis (turban tumor syndrome) (CYLD), two key regulators of necroptosis. Accordingly, both inhibition of RIP-1 and interference with CYLD restored glucocorticoid resistance completely. Together with evidence for a chemosensitizing activity of obatoclax in vivo, our data provide a compelling rationale for clinical translation of this pharmacological approach into treatments for patients with refractory ALL.
Collapse
Affiliation(s)
- Laura Bonapace
- Department of Oncology, University Children's Hospital, University of Zurich, Switzerland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
181
|
Abstract
Although the majority of children with acute lymphoblastic leukemia (ALL) can be cured with combination chemotherapy, the challenge remains to salvage patients with resistant disease and to reduce treatment related toxicity. To meet this challenge, it will be essential to incorporate new agents targeting the biological Achilles Heels of this cancer more rapidly into currently available treatment regimen. Here we review the principles of current ALL therapy, recent advances in understanding ALL biology and discuss a selection of promising areas for drug development that may take advantage of the underlying leukemia biology. We focus particularly on strategies to interfere with common effector mechanisms that can be trigged by different individual oncogenic lesions and on new agents from drug development programs in adult oncology, as such agents will come with better chances for sustainable commercial development.
Collapse
|
182
|
Paik PK, Rudin CM, Brown A, Rizvi NA, Takebe N, Travis W, James L, Ginsberg MS, Juergens R, Markus S, Tyson L, Subzwari S, Kris MG, Krug LM. A phase I study of obatoclax mesylate, a Bcl-2 antagonist, plus topotecan in solid tumor malignancies. Cancer Chemother Pharmacol 2010; 66:1079-85. [PMID: 20165849 DOI: 10.1007/s00280-010-1265-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 02/01/2010] [Indexed: 11/29/2022]
Abstract
PURPOSE To establish the safety, maximum tolerated dose (MTD), recommended phase II dose, and preliminary antitumor activity of obatoclax mesylate (GX15-070MS), a Bcl-2 antagonist, in combination with topotecan in patients with solid tumor malignancies. PATIENTS AND METHODS Patients with solid tumor malignancies for whom topotecan was an appropriate treatment were administered obatoclax mesylate and topotecan on a 3-week cycle in a pre-defined, standard 3 + 3 dose escalation scheme. The starting dose for obatoclax mesylate was 14 mg/m(2) by 3-h intravenous (IV) infusion. Topotecan 1.25 mg/m(2) was given concurrently as an IV infusion on days 1-5 of each cycle. RESULTS Fourteen patients received 40 cycles of obatoclax mesylate at the following doses: 14 mg/m(2) on day 1, 14 mg/m(2) on days 1 and 3, and 20 mg/m(2) on day 1. The most common toxicities related to obatoclax were neurologic, including ataxia, mood alterations, somnolence, and cognitive dysfunction. The majority of these were grades 1 and 2 (88%). Two of five patients experienced dose-limiting grade 3 neurologic toxicity at a dose of 20 mg/m(2); no patients experienced grade 4 neurologic toxicities, and no other patients experienced grade 3 neurologic toxicity. Of the patients who experienced grade 3 neurologic events, one later developed febrile neutropenia, which was also a dose-limiting toxicity (DLT). After an additional three patients were treated without DLT at the previously tolerated dose of 14 mg/m(2) on day 1, the level was escalated to 14 mg/m(2) on days 1 and 3. Three patients were treated at this dose and, with none experiencing a DLT, 14 mg/m(2) on days 1 and 3 was defined as the recommended phase II dose. Two patients with small-cell lung cancer (SCLC) achieved partial responses and four patients had stable disease. Median time to progression (TTP) was 12 weeks. CONCLUSION Obatoclax mesylate administered at 14 mg/m(2) IV on days 1 and 3 is safe and well tolerated when given in combination with topotecan 1.25 mg/m(2) IV on days 1-5 of an every 3-week cycle. A phase II trial to assess the efficacy of this combination for patients with relapsed SCLC is currently accruing patients.
Collapse
Affiliation(s)
- Paul K Paik
- Thoracic Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
183
|
Smoot RL, Blechacz BRA, Werneburg NW, Bronk SF, Sinicrope FA, Sirica AE, Gores GJ. A Bax-mediated mechanism for obatoclax-induced apoptosis of cholangiocarcinoma cells. Cancer Res 2010; 70:1960-9. [PMID: 20160031 DOI: 10.1158/0008-5472.can-09-3535] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Apoptosis induction by BH3 mimetics is a therapeutic strategy for human cancer. These mimetics exert single-agent activity in cells "primed" for cell death. Primed cells are dependent upon antiapoptotic Bcl-2 proteins for survival and are characterized by the ability of the BH3 mimetic to induce cytochrome c release from their isolated mitochondria. Our aim was to examine the single-agent activity of obatoclax, a BH3 mimetic in cholangiocarcinoma cell lines. In clonogenic assays, inhibition of colony formation was observed by obatoclax treatment. Despite single-agent activity by obatoclax, the mitochondria from these cells did not release cytochrome c after incubation with this BH3 mimetic. However, immunofluorescence and cell fractionation studies identified Bax activation and translocation to mitochondria after treatment with obatoclax. shRNA targeted knockdown of Bax doubled the IC50 for obatoclax but did not abrogate its cytotoxicity, whereas knockdown of Bak did not alter the IC50. In a cell-free system, obatoclax induced an activating conformational change of Bax, which was attenuated by a site-directed mutagenesis of a previously identified protein activation site. Finally, the drug also elicited a significant in vivo response in a rodent model of this disease. In conclusion, single-agent obatoclax treatment results in Bax activation, which contributes, in part, to cell death in cholangiocarcinoma cells. These data indicate that BH3 mimetics may also function as direct activators of Bax and induce cytotoxicity in cells not otherwise primed for cell death.
Collapse
Affiliation(s)
- Rory L Smoot
- Division of Gastroenterologic and General Surgery, College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
| | | | | | | | | | | | | |
Collapse
|
184
|
Verheij M, Vens C, van Triest B. Novel therapeutics in combination with radiotherapy to improve cancer treatment: Rationale, mechanisms of action and clinical perspective. Drug Resist Updat 2010; 13:29-43. [DOI: 10.1016/j.drup.2010.01.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/21/2010] [Accepted: 01/22/2010] [Indexed: 12/27/2022]
|
185
|
Abstract
PURPOSE OF REVIEW Members of the Bcl-2 family of proteins are critical components in regulating the intrinsic apoptotic pathway. Bcl-2 protein overexpression is associated with drug resistance and poor clinical outcome in cancer patients. Preclinical and clinical evaluations demonstrate that downregulation of Bcl-2 restores the intrinsic apoptotic pathways with antitumor effects. Thus, Bcl-2 is aggressively pursued as a therapeutic target in cancer with several new drugs undergoing clinical investigations. In this manuscript, we will review clinical information on some of the novel compounds specifically designed to target the Bcl-2 gene product(s). RECENT FINDINGS Extensive clinical evaluations using a Bcl-2-specific antisense have resulted in an overall disappointing experience. But new small molecule inhibitors of the Bcl-2 hold promise with high target affinity, ease of administration and improved toxicity profile. Early stage clinical trials of these agents are revealing promising results alone as well as in combination with existing anticancer therapeutics. Encouraging results from some of these clinical investigations are summarized in this review. SUMMARY Downregulation of Bcl-2 and restoration of a critical apoptotic pathway in cancer cells remains an important strategy. Novel Bcl-2 inhibitors have started to deliver the therapeutic promise of this target-specific quest.
Collapse
|
186
|
Abstract
For the many patients with lymphoma that has relapsed after and/or has become refractory to existing treatments, the development of novel therapeutics is imperative. Investigation into intracellular processes that are dysregulated during lymphomagenesis has uncovered several new potential targets for anticancer agents. Although monoclonal antibodies and other immunotherapeutics have led to dramatic advances in the treatment of patients with lymphoma, the parallel development of small molecule inhibitors has been equally exciting. These agents, whose small size allows direct entry into tumor cells, can target distinct proteins or complexes, thereby disrupting molecular processes on which neoplastic cells depend for survival and growth. This review surveys the published literature on many of these new targeted molecules, focusing on some of the most promising agents for which phase 2 data currently exist. It also explores the potential for incorporating these agents into broader multidrug regimens.
Collapse
|
187
|
|
188
|
Paoluzzi L, O’Connor OA. Targeting Survival Pathways in Lymphoma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010. [DOI: 10.1007/978-1-4419-6706-0_5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
189
|
Anion Binding and Transport by Prodigiosin and Its Analogs. TOPICS IN HETEROCYCLIC CHEMISTRY 2010. [DOI: 10.1007/7081_2010_29] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
190
|
Identification of proapoptotic Bim as a tumor suppressor in neoplastic mast cells: role of KIT D816V and effects of various targeted drugs. Blood 2009; 114:5342-51. [PMID: 19850739 DOI: 10.1182/blood-2008-08-175190] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Systemic mastocytosis (SM) is a myeloid neoplasm involving mast cells (MCs) and their progenitors. In most cases, neoplastic cells display the D816V-mutated variant of KIT. KIT D816V exhibits constitutive tyrosine kinase (TK) activity and has been implicated in increased survival and growth of neoplastic MCs. Recent data suggest that the proapoptotic BH3-only death regulator Bim plays a role as a tumor suppressor in various myeloid neoplasms. We found that KIT D816V suppresses expression of Bim in Ba/F3 cells. The KIT D816-induced down-regulation of Bim was rescued by the KIT-targeting drug PKC412/midostaurin. Both PKC412 and the proteasome-inhibitor bortezomib were found to decrease growth and promote expression of Bim in MC leukemia cell lines HMC-1.1 (D816V negative) and HMC-1.2 (D816V positive). Both drugs were also found to counteract growth of primary neoplastic MCs. Furthermore, midostaurin was found to cooperate with bortezomib and with the BH3-mimetic obatoclax in producing growth inhibition in both HMC-1 subclones. Finally, a Bim-specific siRNA was found to rescue HMC-1 cells from PKC412-induced cell death. Our data show that KIT D816V suppresses expression of proapoptotic Bim in neoplastic MCs. Targeting of Bcl-2 family members by drugs promoting Bim (re)-expression, or by BH3-mimetics such as obatoclax, may be an attractive therapy concept in SM.
Collapse
|
191
|
Abstract
PURPOSE OF REVIEW To review new agents under investigation for the treatment of patients with peripheral T-cell lymphoma. RECENT FINDINGS New agents being evaluated in these patients include histone deacetylase inhibitors (e.g. romidepsin, vorinostat, and balinostat), purine analogs and agents that interfere with the purine metabolic pathway (e.g. forodesine), immunomodulatory agents, proapoptotic small molecules (e.g. oblimersen, obatoclax, and gossypol), antifols (e.g. pralatrexate), proteasome inhibitors (e.g. bortezomib), monoclonal antibodies against T-cell antigens (e.g. CD30 and CD52), and immunotoxins (e.g. denileukin diftitox). SUMMARY The development of rational combinations of such agents in clinical trials will be required to improve the outcome of these patients.
Collapse
|
192
|
Hutcheson J, Perlman H. BH3-only proteins in rheumatoid arthritis: potential targets for therapeutic intervention. Oncogene 2009; 27 Suppl 1:S168-75. [PMID: 19641502 DOI: 10.1038/onc.2009.54] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Rheumatoid arthritis (RA) is a debilitating disease, resulting in the destruction of bone and cartilage, and in the permanent disfigurement of joints. Although the precise cause of RA is currently unresolved, it has become clear that the damaging effects are a result of the toxic milieu caused by an influx of inflammatory cells and the resulting heightened proinflammatory state within the joint. As the amount of literature suggesting that this preponderance of cells is a result of decreased local apoptosis in the joint continues to increase, in this review, we describe how Bcl-2 family pro-apoptotic BH3-only proteins, particularly Bim and Bid, could act to protect against the development of the disease. We also suggest a role for BH3-mimetic drugs as potential therapeutics in the treatment of RA.
Collapse
Affiliation(s)
- J Hutcheson
- Rheumatic Diseases Division, Department of Internal Medicine, University of Texas - Southwestern Medical Center, Simmons Arthritis Research Center, Dallas, TX, USA
| | | |
Collapse
|
193
|
Lomonosova E, Chinnadurai G. BH3-only proteins in apoptosis and beyond: an overview. Oncogene 2009; 27 Suppl 1:S2-19. [PMID: 19641503 DOI: 10.1038/onc.2009.39] [Citation(s) in RCA: 317] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BH3-only BCL-2 family proteins are effectors of canonical mitochondrial apoptosis. They discharge their pro-apoptotic functions through BH1-3 pro-apoptotic proteins such as BAX and BAK, while their activity is suppressed by BH1-4 anti-apoptotic BCL-2 family members. The precise mechanism by which BH3-only proteins mediate apoptosis remains unresolved. The existing data are consistent with three mutually non-exclusive models (1) displacement of BH1-3 proteins from complexes with BH1-4 proteins; (2) direct interaction with and conformational activation of BH1-3 proteins; and (3) membrane insertion and membrane remodeling. The BH3-only proteins appear to play critical roles in restraining cancer and inflammatory diseases such as rheumatoid arthritis. Molecules that mimic the effect of BH3-only proteins are being used in treatments against these diseases. The cell death activity of a subclass of BH3-only members (BNIP3 and BNIP3L) is linked to cardiomyocyte loss during heart failure. In addition to their established role in apoptosis, several BH3-only members also regulate diverse cellular functions in cell-cycle regulation, DNA repair and metabolism. Several members are implicated in the induction of autophagy and autophagic cell death, possibly through unleashing of the BH3-only autophagic effector Beclin 1 from complexes with BCL-2/BCL-xL. The Chapters included in the current Oncogene Review issues provide in-depth discussions on various aspects of major BH3-only proteins.
Collapse
Affiliation(s)
- E Lomonosova
- Institute for Molecular Virology, Saint Louis University School of Medicine, Doisy Research Center, St Louis, MO 63104, USA
| | | |
Collapse
|
194
|
Lajmanovich A, Ribeyron JB, Florin A, Fournier A, Pasquier MA, Duley S, Chauvet M, Plumas J, Bonnefoix T, Gressin R, Leroux D, Callanan MB. Identification, characterisation and regulation by CD40 activation of novel CD95 splice variants in CD95-apoptosis-resistant, human, B-cell non-Hodgkin's lymphoma. Exp Cell Res 2009; 315:3281-93. [PMID: 19751723 DOI: 10.1016/j.yexcr.2009.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 09/01/2009] [Accepted: 09/08/2009] [Indexed: 01/09/2023]
Abstract
CD95 gene and splicing aberrations have been detected in B-cell non-Hodgkin lymphoma (B-NHL) where they are thought to contribute to CD95 apoptosis resistance. To further investigate this, we have performed extensive CD95 transcript sequencing and functional analysis in B-NHL with demonstrated resistance to CD95-induced apoptosis (B-NHLr). Strikingly, instead of showing CD95 mutations per se, B cells from B-NHLr co-expressed wild-type and multiple, normal (CD95nv) and novel alternatively spliced variant CD95 transcripts (CD95av). CD95av were predicted, by sequencing, to encode soluble, potentially apoptosis inhibitory proteins. However, their overexpression, by transfection, in Jurkat cells did not interfere with endogenous CD95 death signalling. Furthermore, CD95av-expressing B-NHLr did not show mutations in CD95 splice-regulatory elements and CD95av expression was 'reversible' by CD40 activation. This, in conjunction with treatment by the protein synthesis inhibitor, cycloheximide, could sensitise a subset of B-NHLr to CD95 apoptosis. In normal and lymphoma B cells, this correlated to increased CD95 membrane expression, enhanced DISC activity and engagement of the mitochondrial death pathway via Bid cleavage, although the latter occurred less efficiently in B-NHLr. Thus, immune modulation of CD95 transcription and alternative splicing combined with enhanced engagement of mitochondrial death signalling offer potential for restoration of CD95 apoptosis sensitivity in B-NHLr.
Collapse
Affiliation(s)
- Alicia Lajmanovich
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble, France.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
195
|
|
196
|
Smith MA. Update on developmental therapeutics for acute lymphoblastic leukemia. Curr Hematol Malig Rep 2009; 4:175-82. [DOI: 10.1007/s11899-009-0024-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
197
|
Abstract
The mainstay of therapy of chronic lymphocytic leukemia (CLL) is cytotoxic chemotherapy; however, CLL is still an incurable disease with resistance to therapy developing in the majority of patients. In recent years, our understanding of the biological basis of CLL pathogenesis has substantially improved and novel treatment strategies are emerging. Tailoring and individualizing therapy according to the molecular and cellular biology of the disease is on the horizon, and advances with targeted agents such as monoclonal antibodies combined with traditional chemotherapy have lead to improved remission rates. The proposed key role of the B-cell receptor (BCR) in CLL pathogenesis has led to a number of possible opportunities for therapeutic exploitation. We are beginning to understand that the microenvironment is of utmost importance in CLL because certain T-cell subsets and stromal cells support the outgrowth and development of the malignant clone. Furthermore, an increase in our understanding of the deregulated cell-death machinery in CLL is a prerequisite to developing new targeted strategies that might be more effective in engaging with the cell-death machinery. This Review summarizes the progress made in understanding these features of CLL biology and describes novel treatment strategies that have also been exploited in current clinical trials.
Collapse
|
198
|
Delmonte A, Ghielmini M, Sessa C. Beyond monoclonal antibodies: new therapeutic agents in non-Hodgkin's lymphomas. Oncologist 2009; 14:511-25. [PMID: 19411316 DOI: 10.1634/theoncologist.2008-0214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The availability of active monoclonal antibodies, either as single agents or in combination with cytotoxic agents, has improved treatment results in non-Hodgkin's lymphoma (NHL). Despite this and the increasing number of available active monoclonal antibodies, alone or conjugated with radioisotopes, not all types of lymphoma are sensitive to these biological agents and often they become resistant because of different molecular mechanisms. New molecular targets in neoplastic cells are emerging and provide the rationale for novel discovery initiatives. In fact, a greater knowledge of the biology of lymphoma and the identification of compounds selectively active against a potential therapeutic pathway have already improved the time to progression and survival time of patients with some subtypes of NHL. The growing list of new drugs provides the exciting prospect of developing disease-specific and even patient-specific therapies. The aim of this review is to identify and discuss non-monoclonal antibody new therapeutic agents in terms of mechanism of action and clinical results. The preclinical and clinical features of proteasome inhibitors, histone deacetylase inhibitors, thalidomide and lenalidomide, mammalian target of rapamycin inhibitors, antisense oligonucleotides, heat shock protein inhibitors, protein kinase C inhibitors, antiangiogenic agents, and new cytotoxics are reviewed.
Collapse
Affiliation(s)
- Angelo Delmonte
- Oncology Institute of Southern Switzerland, Ospedale S. Giovanni, 6500 Bellinzona, Switzerland.
| | | | | |
Collapse
|
199
|
Tan ML, Ooi JP, Ismail N, Moad AIH, Muhammad TST. Programmed Cell Death Pathways and Current Antitumor Targets. Pharm Res 2009; 26:1547-60. [DOI: 10.1007/s11095-009-9895-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 04/11/2009] [Indexed: 12/19/2022]
|
200
|
Abstract
Several inhibitors of BCL2 proteins have been identified that induce apoptosis in a variety of tumor cells, indicating their potential in cancer therapy. We investigated the specificity of six putative BCL2 inhibitors (obatoclax, gossypol, apogossypol, EM20-25, chelerythrine and ABT-737). Using cells deficient either for Bax/Bak or caspase-9, we found that only ABT-737 specifically targeted BCL2 proteins and induced apoptosis by activation of caspase-9, as only ABT-737 induced apoptosis was completely inhibited in cells deficient for Bax/Bak or caspase-9. Our data show that only ABT-737 is a specific BCL2 inhibitor and all other compounds investigated were not specific for BCL2 proteins. Furthermore, investigations of the effects of these compounds in primary chronic lymphocytic leukemic cells showed that all compounds induced certain biochemical hallmarks of apoptosis, such as release of cytochrome c and caspase cleavage. However, they all caused strikingly different ultrastructural changes. ABT-737 induced all the characteristic ultrastructural changes of apoptosis together with early rupture of the outer mitochondrial membrane, whereas obatoclax, chlelerythrine and gossypol induced pronounced mitochondrial swelling with formation of phospholipid inclusions. Therefore, we conclude that biochemical measurements used earlier to define apoptosis like mitochondrial release of cytochrome c and caspase cleavage, are insufficient to distinguish between classic apoptosis and other forms of cell death.
Collapse
|