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Haematologica May 2017Histone deacetylase inhibitors are members of a class of epigenetic drugs that have proven activity in T-cell malignancies, but little is known about their efficacy in...
Histone deacetylase inhibitors are members of a class of epigenetic drugs that have proven activity in T-cell malignancies, but little is known about their efficacy in B-cell lymphomas. Abexinostat is an orally available hydroxamate-containing histone deacetylase inhibitor that differs from approved inhibitors; its unique pharmacokinetic profile and oral dosing schedule, twice daily four hours apart, allows for continuous exposure at concentrations required to efficiently kill tumor cells. In this phase II study, patients with relapsed/refractory non-Hodgkin lymphoma or chronic lymphocytic leukemia received oral abexinostat at 80 mg BID for 14 days of a 21-day cycle and continued until progressive disease or unacceptable toxicity. A total of 100 patients with B-cell malignancies and T-cell lymphomas were enrolled between October 2011 and July 2014. All patients received at least one dose of study drug. Primary reasons for discontinuation included progressive disease (56%) and adverse events (25%). Grade 3 or over adverse events and any serious adverse events were reported in 88% and 73% of patients, respectively. The most frequently reported grade 3 or over treatment-emergent related adverse events were thrombocytopenia (80%), neutropenia (27%), and anemia (12%). Among the 87 patients evaluable for efficacy, overall response rate was 28% (complete response 5%), with highest responses observed in patients with follicular lymphoma (overall response rate 56%), T-cell lymphoma (overall response rate 40%), and diffuse large B-cell lymphoma (overall response rate 31%). Further investigation of the safety and efficacy of abexinostat in follicular lymphoma, T-cell lymphoma, and diffuse large B-cell lymphoma implementing a less dose-intense week-on-week-off schedule is warranted. ().
Topics: Adult; Aged; Aged, 80 and over; Benzofurans; Diarrhea; Disease-Free Survival; Drug Administration Schedule; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, Non-Hodgkin; Male; Middle Aged; Remission Induction; Thrombocytopenia; Treatment Outcome
PubMed: 28126962
DOI: 10.3324/haematol.2016.154377 -
Blood Dec 2016Bruton's tyrosine kinase (BTK) is a critical mediator of survival in B-cell neoplasms. Although BTK inhibitors have transformed therapy in chronic lymphocytic leukemia...
Bruton's tyrosine kinase (BTK) is a critical mediator of survival in B-cell neoplasms. Although BTK inhibitors have transformed therapy in chronic lymphocytic leukemia (CLL), patients with high-risk genetics are at risk for relapse and have a poor prognosis. Identification of novel therapeutic strategies for this group of patients is an urgent unmet clinical need, and therapies that target BTK via alternative mechanisms may fill this niche. Herein, we identify a set of microRNAs (miRs) that target BTK in primary CLL cells and show that the histone deacetylase (HDAC) repressor complex is recruited to these miR promoters to silence their expression. Targeting the HDACs by using either RNA interference against HDAC1 in CLL or a small molecule inhibitor (HDACi) in CLL and mantle cell lymphoma restored the expression of the BTK-targeting miRs with loss of BTK protein and downstream signaling and consequent cell death. We have also made the novel and clinically relevant discovery that inhibition of HDAC induces the BTK-targeting miRs in ibrutinib-sensitive and resistant CLL to effectively reduce both wild-type and C481S-mutant BTK. This finding identifies a novel strategy that may be promising as a therapeutic modality to eliminate the C481S-mutant BTK clone that drives resistance to ibrutinib and provides the rationale for a combination strategy that includes ibrutinib to dually target BTK to suppress its prosurvival signaling.
Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Animals; Benzofurans; Cell Survival; Clone Cells; Drug Resistance, Neoplasm; Drug Synergism; Epigenesis, Genetic; Gene Expression Profiling; Gene Silencing; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Leukemia, Lymphocytic, Chronic, B-Cell; Mice, Inbred C57BL; MicroRNAs; Molecular Targeted Therapy; Mutant Proteins; Neoplasm Proteins; Piperidines; Promoter Regions, Genetic; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; RNA Interference; Signal Transduction; Up-Regulation
PubMed: 27756747
DOI: 10.1182/blood-2016-07-727750 -
Stem Cells Translational Medicine Aug 2016: The epigenetic mechanisms promoting lineage-specific commitment of human skeletal (mesenchymal or stromal) stem cells (hMSCs) into adipocytes or osteoblasts are still...
UNLABELLED
: The epigenetic mechanisms promoting lineage-specific commitment of human skeletal (mesenchymal or stromal) stem cells (hMSCs) into adipocytes or osteoblasts are still not fully understood. Herein, we performed an epigenetic library functional screen and identified several novel compounds, including abexinostat, which promoted adipocytic and osteoblastic differentiation of hMSCs. Using gene expression microarrays, chromatin immunoprecipitation for H3K9Ac combined with high-throughput DNA sequencing (ChIP-seq), and bioinformatics, we identified several key genes involved in regulating stem cell proliferation and differentiation that were targeted by abexinostat. Concordantly, ChIP-quantitative polymerase chain reaction revealed marked increase in H3K9Ac epigenetic mark on the promoter region of AdipoQ, FABP4, PPARγ, KLF15, CEBPA, SP7, and ALPL in abexinostat-treated hMSCs. Pharmacological inhibition of focal adhesion kinase (PF-573228) or insulin-like growth factor-1R/insulin receptor (NVP-AEW51) signaling exhibited significant inhibition of abexinostat-mediated adipocytic differentiation, whereas inhibition of WNT (XAV939) or transforming growth factor-β (SB505124) signaling abrogated abexinostat-mediated osteogenic differentiation of hMSCs. Our findings provide insight into the understanding of the relationship between the epigenetic effect of histone deacetylase inhibitors, transcription factors, and differentiation pathways governing adipocyte and osteoblast differentiation. Manipulating such pathways allows a novel use for epigenetic compounds in hMSC-based therapies and tissue engineering.
SIGNIFICANCE
This unbiased epigenetic library functional screen identified several novel compounds, including abexinostat, that promoted adipocytic and osteoblastic differentiation of human skeletal (mesenchymal or stromal) stem cells (hMSCs). These data provide new insight into the understanding of the relationship between the epigenetic effect of histone deacetylase inhibitors, transcription factors, and differentiation pathways controlling adipocyte and osteoblast differentiation of hMSCs. Manipulating such pathways allows a novel use for epigenetic compounds in hMSC-based therapies for tissue engineering, bone disease, obesity, and metabolic-disorders.
Topics: Adipocytes; Adipogenesis; Benzofurans; Cell Differentiation; Cell Line; Cell Lineage; Chromatin Immunoprecipitation; Computational Biology; Epigenesis, Genetic; Gene Expression Profiling; Gene Expression Regulation, Developmental; Gene Library; Genotype; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Mesenchymal Stem Cells; Myoblasts, Skeletal; Oligonucleotide Array Sequence Analysis; Osteoblasts; Osteogenesis; Phenotype; Signal Transduction; Transcription Factors
PubMed: 27194745
DOI: 10.5966/sctm.2015-0331 -
Cancer Apr 2015
Topics: Antibiotics, Antineoplastic; Benzofurans; Doxorubicin; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Male; Sarcoma
PubMed: 25537232
DOI: 10.1002/cncr.29177 -
Cancer Apr 2015It has been demonstrated that several inhibitors of histone deacetylase (HDAC) can enhance chemotherapy-induced apoptosis and reduce sarcoma tumor volume in preclinical...
BACKGROUND
It has been demonstrated that several inhibitors of histone deacetylase (HDAC) can enhance chemotherapy-induced apoptosis and reduce sarcoma tumor volume in preclinical models. The authors sought to determine the maximum tolerated dose, pharmacokinetics/pharmacodynamics, safety, and toxicity of the HDAC inhibitor abexinostat (PCI-24781) when administered with doxorubicin to patients with metastatic sarcomas.
METHODS
Participants were enrolled in a standard, phase 1, 3 + 3, dose-escalation study design. Abexinostat was administered on days 1 through 5 with 75 mg/m(2) of doxorubicin administered on day 4 of every 21-day cycle until patients developed disease progression or drug intolerance or reached a cumulative lifetime doxorubicin dose of 450 mg/m(2). Granulocyte-colony-stimulating factor (G-CSF) support was provided at physician discretion on arm A and was provided to all participants in arm B. From 3 to 6 participants initially received abexinostat 30 mg/m(2) twice daily, and subsequent cohorts were administered doses of 15 mg/m(2), 45 mg/m(2), or 60 mg/m(2) twice daily. All patients without progressive disease after receiving a cumulative lifetime doxorubicin dose of 450 mg/m(2) were given the option to continue with abexinostat as a single agent until they developed disease progression.
RESULTS
In total, 22 participants (10 who had previously experienced tumor growth after doxorubicin therapy) were enrolled (6 in arm A, 14 in arm B), 20 were evaluable for dose-limiting toxicity (DLT), and 17 were evaluable for radiologic response. In arm A, participants received abexinostat 15 mg/m(2) or 30 mg/m(2) twice daily. DLTs of grade 3 and 4 neutropenia were observed in 2 of 3 participants who received abexinostat 30 mg/m(2) twice daily. Neither of those patients received G-CSF prophylaxis. In arm B, participants received abexinostat at doses of 30 mg/m(2), 45 mg/m(2), or 60 mg/m(2) twice daily, all with mandated G-CSF support. Two DLTs were observed at the 60 mg/m(2) twice-daily dose (grade 3 infection, grade 4 thrombocytopenia). The pharmacokinetics of abexinostat were not affected by doxorubicin. HDAC activity, as measured by histone acetylation in peripheral blood mononuclear cells, was maximally inhibited at the abexinostat 30 mg/m(2) twice-daily dose. Of the 17 participants who were evaluable for radiologic response, 1 patient had a partial response, 9 patients had stable disease, and 7 patients had progressive disease as their best response; and 8 patients completed ≥ 5 cycles. Three of those participants had stable disease as their most recent disease status when the current report was written. Four participants who continued on monotherapy remained in stable disease for a median of 9.8 weeks after completing doxorubicin. The most common toxicities were fatigue, thrombocytopenia, and anemia. No study-related deaths were observed.
CONCLUSIONS
The maximum tolerated dose for abexinostat was 45 mg/m(2) twice daily administered on days 1 through 5 when patients received doxorubicin 75 mg/m(2) on day 4 of a 3-week cycle and G-CSF support was mandated. Toxicities were manageable, and tumor responses were observed. Additional studies are needed to further define the specific contributions of HDAC inhibition in patients who receive doxorubicin for the treatment of metastatic sarcoma.
Topics: Administration, Oral; Adult; Aged; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Benzofurans; Doxorubicin; Drug Administration Schedule; Female; Granulocyte Colony-Stimulating Factor; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Male; Maximum Tolerated Dose; Middle Aged; Sarcoma; Treatment Outcome; Young Adult
PubMed: 25536954
DOI: 10.1002/cncr.29175 -
World Journal of Gastroenterology Aug 2014To explore the efficacy of PCI-24781, a broad-spectrum, hydroxamic acid-derived histone deacetylase inhibitor, in the treatment of gastric cancer (GC).
AIM
To explore the efficacy of PCI-24781, a broad-spectrum, hydroxamic acid-derived histone deacetylase inhibitor, in the treatment of gastric cancer (GC).
METHODS
With or without treatment of PCI-24781 and/or cis-diamminedichloroplatinum (CDDP), GC cell lines were subjected to functional analysis, including cell growth, apoptosis and clonogenic assays. Chromatin immunoprecipitation and luciferase reporter assays were used to determine the interacting molecules and the activity of the enzyme. An in vivo study was carried out in GC xenograft mice. Cell culture-based assays were represented as mean ± SD. ANOVA tests were used to assess differences across groups. All pairwise comparisons between tumor weights among treatment groups were made using the Tukey-Kramer method for multiple comparison adjustment to control experimental-wise type I error rates. Significance was set at P < 0.05.
RESULTS
PCI-24781 significantly reduced the growth of the GC cells, enhanced cell apoptosis and suppressed clonogenicity, and these effects synergized with the effects of CDDP. PCI-24781 modulated the cell cycle and significantly reduced the expression of RAD51, which is related to homologous recombination. Depletion of RAD51 augmented the biological functions of PCI-24781, CDDP and the combination treatment, whereas overexpressing RAD51 had the opposite effects. Increased binding of the transcription suppressor E2F4 on the RAD51 promoter appeared to play a major role in these processes. Furthermore, significant suppression of tumor growth and weight in vivo was obtained following PCI-24781 treatment, which synergized with the anticancer effect of CDDP.
CONCLUSION
These data suggest that RAD51 potentiates the synergistic effects of chemotherapy with PCI-24781 and CDDP on GC.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzofurans; Binding Sites; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cisplatin; Dose-Response Relationship, Drug; Drug Synergism; E2F4 Transcription Factor; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Mice, SCID; Promoter Regions, Genetic; Rad51 Recombinase; Signal Transduction; Stomach Neoplasms; Time Factors; Transfection; Tumor Burden; Xenograft Model Antitumor Assays
PubMed: 25110436
DOI: 10.3748/wjg.v20.i29.10094