Steven Grant

Southwestern University of Finance and Economics, Hua-yang, Sichuan, China

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Publications (406)2285.01 Total impact

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    ABSTRACT: Two classes of novel agents i.e., NAE (NEDD8-activating enzyme) and HDAC (histone deacetylase) inhibitors have shown single-agent activity in AML/MDS. Here we examined mechanisms underlying interactions between the NAE inhibitor pevonedistat (MLN4924) and the approved HDAC inhibitor belinostat in AML/MDS cells. MLN4924/belinostat co-administration synergistically induced AML cell apoptosis (~ 20% individually; 60-90% combined; CI values <1.0) with or without p53 deficiency or FLT3-ITD, while p53 shRNA knock-down or enforced FLT3-ITD expression significantly sensitized cells to the regimen (P < 0.05). MLN4924 blocked belinostat-induced anti-apoptotic gene expression through NF-κB inactivation. Each agent up-regulated Bim, and Bim knock-down significantly attenuated apoptosis. Microarrays revealed distinct DNA damage response (DDR) genetic profiles between individual versus combined MLN4924/belinostat exposure. Whereas belinostat abrogated the MLN4924-activated intra-S checkpoint through Chk1 and Wee1 inhibition/down-regulation, co-treatment down-regulated multiple HR and NHEJ repair proteins, triggering robust DSBs, chromatin pulverization, and apoptosis. Consistently, Chk1 or Wee1 shRNA knockdown significantly sensitized AML cells to MLN4924. MLN4924/belinostat displayed activity against primary AML or MDS cells, including those carrying NGS-defined poor-prognostic cancer hotspot mutations, and CD34(+)/CD38(-)/CD123(+) populations, but not normal CD34(+) progenitors. Finally, combined treatment markedly reduced tumor burden and significantly prolonged animal survival (median survival 205 vs 106 days; P < 0.0001) in both s.c. and i.v. AML xenograft models with negligible toxicity, accompanied by pharmacodynamic effects observed in vitro. Collectively, these findings argue that MLN4924 and belinostat interact synergistically by reciprocally disabling the DDR in AML/MDS cells. This strategy warrants further consideration in AML/MDS, particularly in disease with unfavorable genetic aberrations.
    No preview · Article · Feb 2016 · Blood
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    Full-text · Dataset · Jan 2016
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    Daniel J Klionsky · Kotb Abdelmohsen · Akihisa Abe · Md Joynal Abedin · Hagai Abeliovich · Abraham Acevedo Arozena · Hiroaki Adachi · Christopher M Adams · Peter D Adams · Khosrow Adeli · [...] · Xiao-Feng Zhu · Yuhua Zhu · Shi-Mei Zhuang · Xiaohong Zhuang · Elio Ziparo · Christos E Zois · Teresa Zoladek · Wei-Xing Zong · Antonio Zorzano · Susu M Zughaier ·
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    ABSTRACT: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure flux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagy-related protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular assays, we hope to encourage technical innovation in the field.
    Full-text · Article · Jan 2016 · Autophagy
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    Yun Dai · Prithviraj Bose · Steven Grant

    Full-text · Chapter · Jan 2016
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    ABSTRACT: Effects of concurrent inhibition of mTORC1/2 and Bcl-2/Bcl-xL in human acute myeloid leukemia cells were examined. Dual tetracycline-inducible Bcl-2/Bcl-xL knock-down markedly sensitized acute myeloid leukemia cells to the dual TORC1/2 inhibitor INK128 in vitro as well as in vivo. Moreover, INK128 co-administered with the Bcl-2/xL antagonist ABT-737 sharply induced cell death in multiple acute myeloid leukemia cell lines, including TKI-resistant FLT3-ITD mutants and primary acute myeloid leukemia blasts carrying various genetic aberrations e.g., FLT3, IDH2, NPM1, and Kras, while exerting minimal toxicity toward normal hematopoietic CD34+ cells. Combined treatment was particularly active against CD34+/CD38-/CD123+ primitive leukemia progenitor cells. The INK128/ABT-737 regimen was also effective in the presence of a protective stromal micro-environment. Notably, INK128 was more potent than the TORC1 inhibitor rapamycin in down-regulating Mcl-1, diminishing AKT and 4EBP1 phosphorylation, and potentiating ABT-737 activity. Mcl-1 ectopic expression dramatically attenuated INK128/ABT737 lethality, indicating an important functional role for Mcl-1 down-regulation in INK128/ABT-737 actions. Immunoprecipitation analysis revealed that combined treatment markedly diminished Bax, Bak, and Bim binding to all major anti-apoptotic Bcl-2 members (Bcl-2/Bcl-xL/Mcl-1), while Bax/Bak knock-down reduced cell death. Finally, INK128/ABT-737 co-administration sharply attenuated leukemia growth and significantly prolonged survival in a systemic acute myeloid leukemia xenograft model. Analysis of subcutaneous acute myeloid leukemia-derived tumors revealed significant decrease in 4EBP1 phosphorylation and Mcl-1 protein level, consistent with results obtained in vitro. These findings demonstrate that co-administration of dual mTORC1/mTORC2 inhibitors and BH3-mimetics exhibits potent anti-leukemic activity in vitro and in vivo, arguing that this strategy warrants attention in acute myeloid leukemia.
    Full-text · Article · Oct 2015 · Haematologica
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    ABSTRACT: Purpose: AZD6244 is a MEK1/2 inhibitor with significant preclinical activity in multiple myeloma (MM) cells. This phase 2 study used a two-stage Simon design to determine the AZD6244 response rate in patients with relapsed or refractory MM. Experimental design: AZD6244 (75 mg) was administered orally, twice a day, continuously for 28-day cycles. Response was evaluated after 3 cycles. Results: Thirty-six patients received therapy. The median age was 65 years (range: 43-81) and the median number of prior therapies was 5 (range: 2-11). The most common grade 3 and 4 toxicities included anemia, neutropenia, thrombocytopenia, diarrhea, and fatigue. Three deaths occurred possibly related to AZD6244 (2 due to sepsis, 1 due to acute kidney injury). After AZD6244 discontinuation, 3 additional deaths occurred due to disease progression. The response rate (CR + PR) was 5.6% with a mean duration of response of 4.95 months and median progression-free survival time of 3.52 months. One patient had a very good partial response (VGPR), 1 patient had a partial response, 17 patients had stable disease, 13 patients had progressive disease, and 4 patients could not be assessed for response. Pharmacodynamic studies revealed variable effects on bone marrow CD138+ cell MEK1/2 and ERK1/2 phosphorylation. The best clinical response, a prolonged VGPR, occurred in a patient with an MMSET translocation. Conclusions: Single-agent AZD6244 was tolerable and had minimal activity in this heavily pre-treated population.
    No preview · Article · Oct 2015 · Clinical Cancer Research

  • No preview · Article · Sep 2015 · Clinical Cancer Research
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    ABSTRACT: A phase 1 study with carfilzomib and vorinostat was conducted in 20 B-cell lymphoma patients. Vorinostat was given orally twice daily on days 1, 2, 3, 8, 9, 10, 15, 16, and 17 followed by carfilzomib (given as a 30 min infusion) on days 1, 2, 8, 9, 15, and 16. A treatment cycle was 28 days. Dose escalation initially followed a standard 3+3 design, but adapted a more conservative accrual rule following dose de-escalation. The maximum tolerated dose was 20 mg/m2 carfilzomib and 100 mg vorinostat (twice daily). The dose-limiting toxicities were grade 3 pneumonitis, hyponatremia, and febrile neutropenia. One patient had a partial response and 2 patients had stable disease. Correlative studies showed a decrease in NF-κB activation and an increase in Bim levels in some patients, but these changes did not correlate with clinical response. Trial Registration ID: NCT01276717.
    Full-text · Article · Aug 2015 · Leukemia & lymphoma
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    ABSTRACT: Chromodomain Helicase DNA-binding protein 4 (CHD4) is an ATPase that alters the phasing of nucleosomes on DNA and has recently been implicated in DNA double stranded break (DSB) repair. Here, we show that depletion of CHD4 in Acute Myeloid Leukemia (AML) blasts induces a global relaxation of chromatin that renders cells more susceptible to DSB formation, while concurrently impeding their repair. Furthermore, CHD4 depletion renders AML blasts more sensitive both in vitro and in vivo to genotoxic agents used in clinical therapy: daunorubicin (DNR) and cytarabine (ara-C). Sensitization to DNR and ara-C is mediated in part by activation of the ATM pathway, which is preliminarily activated by a Tip60-dependent mechanism in response to chromatin relaxation and further activated by genotoxic-agent induced DSBs. This sensitization preferentially affects AML cells, as CHD4 depletion in normal CD34(+) hematopoetic progenitors does not increase their susceptibility to DNR or ara-C. Unexpectedly, we found that CHD4 is necessary for maintaining the tumor forming behavior of AML cells, as CHD4 depletion severely restricted the ability of AML cells to form xenografts in mice and colonies in soft agar. Taken together, these results provide evidence for CHD4 as a novel therapeutic target whose inhibition has the potential to enhance the effectiveness of genotoxic agents used in AML therapy. Copyright © 2015 American Society of Hematology.
    No preview · Article · Aug 2015 · Blood

  • No preview · Article · Aug 2015 · Cancer Research
  • Victor Y Yazbeck · Steven Grant
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    ABSTRACT: Introduction: Patients with relapsed or refractory lymphoma remain a population with unmet medical needs. Histone deacetylase inhibitors (HDACIs) represent a novel class of anticancer drugs currently in development in several malignancies. Inhibition of HDACs leads to acetylation of histone and non-histone proteins, which in turn results in epigenetic modification of gene expression that leads to a plethora of effects, such as cell cycle arrest, apoptosis and inhibition of angiogenesis. Romidepsin is a novel HDACI that has demonstrated preclinical and clinical activity. Areas covered: This review discusses the different HDACs and epigenetic regulation with a particular focus on the preclinical and clinical development of romidepsin in lymphoma. The review of romidepsin includes: the mechanism of action, its synergistic interaction with novel agents, pivotal clinical trials that lead to its US FDA approval in cutaneous T-cell lymphoma and peripheral T-cell lymphoma as well as active combinations currently in clinical trials. Expert opinion: Romidepsin is a potent HDACI with clinical activity in T-cell lymphoma where novel agents and combinations are desperately needed. A deeper understanding of the molecular characteristics of this class of agents will allow the design of more potent drugs with improved toxicity profiles and future rational combinations that will expand the indication and benefit from these novel agents.
    No preview · Article · May 2015 · Expert Opinion on Investigational Drugs
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    Prithviraj Bose · Steven Grant
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    ABSTRACT: Despite modest improvements in survival over the last several decades, the treatment of AML continues to present a formidable challenge. Most patients are elderly, and these individuals, as well as those with secondary, therapy-related, or relapsed/refractory AML, are particularly difficult to treat, owing to both aggressive disease biology and the high toxicity of current chemotherapeutic regimens. It has become increasingly apparent in recent years that coordinated interruption of cooperative survival signaling pathways in malignant cells is necessary for optimal therapeutic results. The modest efficacy of monotherapy with both cytotoxic and targeted agents in AML testifies to this. As the complex biology of AML continues to be elucidated, many " synthetic lethal " strategies involving rational combinations of targeted agents have been developed. Unfortunately, relatively few of these have been tested clinically, although there is growing interest in this area. In this article, the preclinical and, where available, clinical data on some of the most promising rational combinations of targeted agents in AML are summarized. While new molecules should continue to be combined with conventional genotoxic drugs of proven efficacy, there is perhaps a need to OPEN ACCESS J. Clin. Med. 2015, 4 635 rethink traditional philosophies of clinical trial development and regulatory approval with a focus on mechanism-based, synergistic strategies.
    Full-text · Article · Apr 2015 · Journal of Clinical Medicine
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    Hong-Bin Fang · Xuerong Chen · Xin-Yan Pei · Steven Grant · Ming Tan
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    ABSTRACT: Drug combination is a critically important therapeutic approach for complex diseases such as cancer and HIV due to its potential for efficacy at lower, less toxic doses and the need to move new therapies rapidly into clinical trials. One of the key issues is to identify which combinations are additive, synergistic, or antagonistic. While the value of multidrug combinations has been well recognized in the cancer research community, to our best knowledge, all existing experimental studies rely on fixing the dose of one drug to reduce the dimensionality, e.g. looking at pairwise two-drug combinations, a suboptimal design. Hence, there is an urgent need to develop experimental design and analysis methods for studying multidrug combinations directly. Because the complexity of the problem increases exponentially with the number of constituent drugs, there has been little progress in the development of methods for the design and analysis of high-dimensional drug combinations. In fact, contrary to common mathematical reasoning, the case of three-drug combinations is fundamentally more difficult than two-drug combinations. Apparently, finding doses of the combination, number of combinations, and replicates needed to detect departures from additivity depends on dose-response shapes of individual constituent drugs. Thus, different classes of drugs of different dose-response shapes need to be treated as a separate case. Our application and case studies develop dose finding and sample size method for detecting departures from additivity with several common (linear and log-linear) classes of single dose-response curves. Furthermore, utilizing the geometric features of the interaction index, we propose a nonparametric model to estimate the interaction index surface by B-spine approximation and derive its asymptotic properties. Utilizing the method, we designed and analyzed a combination study of three anticancer drugs, PD184, HA14-1, and CEP3891 inhibiting myeloma H929 cell line. To our best knowledge, this is the first ever three drug combinations study performed based on the original 4D dose-response surface formed by dose ranges of three drugs. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
    Full-text · Article · Mar 2015 · Statistical Methods in Medical Research
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    Yun Dai · Steven Grant
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    ABSTRACT: A variety of anticancer agents employed in standard chemotherapy or novel targeted therapy induce autophagy. A cytoprotective autophagic response often counteracts apoptosis triggered by such agents, potentially contributing to acquired drug-resistance. It is recognized that autophagy and apoptosis share molecular regulatory mechanisms primarily governed by multidomain anti-apoptotic members (e.g., BCL2/Bcl-2 and BCL2L1/Bcl-xL) of the BCL2 family. However, the role of pro-apoptotic BH3-only proteins (e.g.,, BCL2L11/Bim), another class of BCL2 family proteins that critically determine therapeutic responses, in autophagy regulation remains largely unexplored, particularly with respect to mechanisms of acquired drug resistance.
    Full-text · Article · Feb 2015 · Autophagy
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    ABSTRACT: The present studies were to determine whether the multi-kinase inhibitor sorafenib or its derivative regorafenib interacted with the ERBB1/ERBB2 inhibitor lapatinib to kill CNS tumor cells. In multiple CNS tumor cell types sorafenib and lapatinib interacted in a greater than additive fashion to cause tumor cell death. Tumor cells lacking PTEN, and anoikis or lapatinib resistant cells were as sensitive to the drug combination as cells expressing PTEN or parental cells, respectively. Similar data were obtained using regorafenib. Treatment of brain cancer cells with [sorafenib + lapatinib] enhanced radiation toxicity. The drug combination increased the numbers of LC3-GFP vesicles; this correlated with a reduction in endogenous LC3II, and p62 and LAMP2 degradation. Knock down of Beclin1 or ATG5 significantly suppressed drug combination lethality. Expression of c-FLIP-s, BCL-XL, or dominant negative caspase 9 reduced drug combination toxicity; knock down of FADD or CD95 was protective. Expression of both activated AKT and activated MEK1 or activated mTOR was required to strongly suppress drug combination lethality. As both lapatinib and sorafenib are FDA approved agents, our data argue for further determination as to whether lapatinib and sorafenib is a useful glioblastoma therapy. J. Cell. Physiol. 230: 131-139, 2015. © 2014 Wiley Periodicals, Inc.
    No preview · Article · Jan 2015 · Journal of Cellular Physiology
  • Prithviraj Bose · Steven Grant
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    ABSTRACT: The Bcl-2 family of antiapoptotic and proapoptotic proteins serve as key regulators of the mitochondrial pathway of apoptosis. Multiple signals from a variety of cell death stimuli converge upon mitochondria to trigger the intrinsic apoptotic cascade. Bcl-2 family proteins are intimately related to prognosis and therapeutic resistance in acute myeloid leukemia (AML), making them rational targets for drug development. Also, directly targeting Bcl-2 family proteins circumvents many of the problems associated with targeting upstream molecules. The Bcl-2 antisense oligonucleotide oblimersen failed to live up to its initial promise in large phase III trials. The discovery of ABT-737, a novel, small-molecule inhibitor of specific protein–protein interactions, gave a much-needed impetus to the field of “BH3 mimetic” research. The demonstration that Mcl-1, an antiapoptotic Bcl-2 family protein that is not inhibited by ABT-737 or its analogs, is of crucial importance in AML, underscores the need for rational drug combinations that simultaneously target multiple arms of the apoptotic regulatory machinery.
    No preview · Chapter · Jan 2015
  • S Grant
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    ABSTRACT: Keywords: Histone deacetylase inhibitors; NAE inhibitors; MLN4924; Wee1; leukemia stem cells; leukemia-initiating cells; DNA damage response
    No preview · Article · Dec 2014

  • No preview · Conference Paper · Dec 2014
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    ABSTRACT: Interactions between the dual BCR/ABL and Src inhibitor bosutinib and the Chk1 inhibitor PF-00477736 were examined in BCR/ABL+ leukemia cells, particularly imatinib-resistant cells, including those with the T315I mutation. Bosutinib blocked PF-00477736-induced ERK1/2 activation and sharply increased apoptosis in association with Mcl-1 inhibition, p34(cdc2) dephosphorylation, BimEL up-regulation, and DNA damage in imatinib-resistant CML or Ph+ ALL cell lines. Inhibition of Src or MEK1 by shRNA significantly enhanced PF-0047736 lethality. Bosutinib/PF-00477736 co-treatment also potentiated cell death in CD34+ CML patient samples, including dasatinib-resistant blast crisis cells exhibiting both T315I and E355G mutations, but was minimally toxic to normal CD34+ cells. Finally, combined in vivo treatment significantly suppressed BaF3/T315I tumor growth and prolonged survival in an allogeneic mouse model. Together, these findings suggest that this targeted combination strategy warrants attention in IM-resistant CML or Ph+ ALL.
    No preview · Article · Nov 2014 · Leukemia Research

  • No preview · Conference Paper · Nov 2014

Publication Stats

17k Citations
2,285.01 Total Impact Points

Institutions

  • 2015
    • Southwestern University of Finance and Economics
      Hua-yang, Sichuan, China
  • 2-2015
    • Virginia Commonwealth University
      • • Division of Hematology/Oncology
      • • School of Medicine
      • • Department of Biochemistry and Molecular Biology
      • • Massey Cancer Center
      • • Department of Radiation Oncology
      • • Department of Microbiology & Immunology
      • • Department of Pharmacology and Toxicology
      Ричмонд, Virginia, United States
  • 1994-2013
    • Richmond VA Medical Center
      Ричмонд, Virginia, United States
    • Arizona State University
      • Cancer Research Institute
      Phoenix, Arizona, United States
  • 2003
    • University of Richmond
      Ричмонд, Virginia, United States
    • Boston University
      Boston, Massachusetts, United States
  • 1991
    • Medical University of South Carolina
      • Division of Hematology/Oncology
      Charleston, South Carolina, United States
  • 1984-1987
    • CUNY Graduate Center
      New York, New York, United States
  • 1982-1985
    • Columbia University
      • • Department of Medicine
      • • College of Physicians and Surgeons
      New York, New York, United States