bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms and Activity of PPARγ-Active Triterpenoids CDDO and CDDO-Me in Leukemias.
Authors: Konopleva Marina , Samudio Ismael , Tsao Twee , Kornblau Steven M. , Shi Yue-Xi , McQueen Teresa , Contractor Rooha , Sporn Michael B. , Meyer Colin J. , Huff Warren , Safe Stephen H. , Kantarjian Hagop , Andreeff Michael 
Published: April 2020

Abstract
First-line therapy of acute myeloid leukemia (AML) consists of combinations of cytarabine and an anthracycline. While initial complete remissions are frequent, most patients succumb to resistant disease underlining the need for novel, more effective agents. The most striking progress in AML therapy was achieved by targeting the nuclear receptor RARα with ATRA. Research in our laboratory has demonstrated that the novel synthetic triterpenoid CDDO (2-cyano-3,12- dioxooleana-1,9-dien-28-oic acid) and its more active C28 methyl ester derivative CDDO-Me inhibit growth and induce apoptosis in a variety of cancers including AML, CLL and blast crisis CML. CDDO and to a much higher degree CDDO-Me are potent activators of the nuclear transcription factor Peroxisome Proliferator-Activated Receptor gamma (PPARγ). In a mammalian two-hybrid assay, the CDDO and CDDO-Me induced activation of PPARγ was associated with a marked increase in multiple coactivator recruitment (SRC-1, SRC-2, SRC-3, TRAP220/DRIP205, CARM-1 and PGC-1) that is qualitatively different from that induced by other PPARγ ligands. CDDO induced a higher degree of myelo-monocytic differentiation in DRIP205-overexpressing HL-60 cells suggesting that high cellular levels of DRIP205 co-activator modulate differentiation response to PPARγ ligation. CDDO induced p21 mRNA and protein in leukemic cells and transactivation of the p21 promoter in a p53-independent fashion. We have recently identified the PPARγ-independent depletion of mitochondrial glutathione (GSHm) as a novel mechanism of action resulting in redox disbalance and mitochondrial damage as mechanisms of pro-apoptotic effects of CDDO and CDDO-Me. Gene expression studies using cDNA arrays demonstrate that CDDO induces genes involved in the antioxidant response (AR) including phase II detoxifying enzymes (glutamate cysteine ligase, GSH transferase, etc.) and antioxidant enzymes (heme oxygenase 1, thioredoxin reductase). Cotreatment with the GSH precursor, n-acetyl cystein prevented apoptosis and loss of viability induced by CDDOs, whereas alkylation of intracellular thiols by diethylmaleate decreased the accumulation of a biotinylated derivative of CDDO, TP-301, in U937 leukemic cells suggesting that intracellular reduced thiols are functional targets of CDDO and its derivatives. The in vivo studies using liposomal CDDO-Me in a conditional leukemia model demonstrated significant reduction of leukemia burden as measured by bioluminescence imaging and prolongation of survival. Based on the ample pre-clinical evidence of anti-leukemia effects and on the favorable PK/toxicity profile of the parental compound, CDDO will enter Phase I clinical trials in hematologic malignancies in 3Q 2005 and CDDO-Me in 1Q 2006.
The HIV-Protease Inhibitor Ritonavir(Norvir®) Is Active Against Human AML Blasts In Vitro and In Vivo and Has Synergistic Cytotoxic Activity with the Proteaseome Inhibitor Bortezomib (Velcade®).
Authors: Driessen Christoph , Hendrik Müller-Ide , Jeanette Gogel , Marianne Kraus , Lothar Kanz , Thomas Rückrich 
Published: April 2020

Abstract
Upregulation of alternative proteolytic pathways characterizes malignant cells that overcome proteasome inhibition in vitro. The proteasome inhibitor Bortezomib (Velcade®), which selectively targets only one of the three active subunits of the proteasome, has shown limited activity in AML. Ritonavir (Norvir®) is an aspartate protease inhibitor used in intensive HIV-therapy, where therapeutic levels of 5–20μM are reached with an oral dose of 1200 mg/d. A cytotoxic effect of Ritonavir against malignant cells due to proteasome inhibition has been suggested (Gaedicke et al., Cancer Research 62, December 1, 2002). We have here tested the effect of Ritonavir on AML cells, both as single agent and in combination with Bortezomib. Ritonavir induced cytotoxic death in AML cell lines and primary AML blasts with an IC50 of 30–40 μM in vitro. The combination of Ritonavir and Bortezomib was synergistic in vitro, i.e. subtoxic concentrations of Ritonavir at 10 μM combined with subtoxic Bortezomib 5–10 nM induced robust cytotoxicity in AML cell lines and freshly isolated primary AML blasts. Using a novel chemical probe that for the first time allows to visualize the individual activity of proteasomal subunits in intact AML blasts, we show that Velcade selectively abrogates β5 proteasomal activity at 20 nM in AML cells, as expected. Ritonavir, by contrast, had no effect on active proteasomal subunits up to 50 μM. Thus, the synergistic effect of Ritonavir with Bortezomib on AML cells is not due to inhibition of the same proteasomal target by both drugs, but more likely mediated by blocking alternative proteolytic pathways. One individual patient aged 72 years with an early relaps of AML was treated with Ritonavir 400–600 mg/d p.o.. During treatment, the absolute leukocyte count dropped from 24000/μl to 8000/μl while the ANC raised from 185/μl to 1530/μl. Ritonavir was withdrawn due to diarrhoea and abdominal cramps, leading to a sharp increase in peripheral blood blasts and leukocytes. Retreatment with Ritonavir at a reduced dose of 200 mg/d combined with Velcade 1mg/sqm was tolerated and stabilized leukocyte counts for a short period of time. We conclude that Ritonavir has activity against chemotherapy-refractory AML in vitro and in vivo. The combination of Velcade and Ritonavir might allow to synergistically target the proteolytic machinery of AML blasts with tolerable toxicity.
NF-κB Blockade Induces Apoptosis and Decreases Costimulatory Molecules and IL-12 Secretion of Dendritic Cells, Altering DC Maturation: Role in Induction of Tolerance after Transplantation.
Authors: Abarca Luis I. Sanchez , Perez-Simon Jose A. , Blanco Belen , Gutierrez Norma , Mateos Juan , Vidriales Belen , Lopez-Holgado Natalia , Alberca Mercedes , Villaron Eva , Schenkein D. , Canizo Consuelo , San Miguel Jesus F. 
Published: April 2020

Abstract
In steady state, dendritic cells (DC) are in an immature status and maintain tolerance to self antigens. By contrast, if DC maturation is stimulated, as it occurs in the proinflamatory milieu induced by allogeneic transplantation, they trigger effector and memory T cells and, for this reason, they play an essential role in the development of graft versus host disease (GVHD). DC maturation and survival is dependent on NF-kB. Thus, we explored the ability of the proteosome inhibitor bortezomib (B), which prevents Nuclear Factor kB (NF-kB) activation, to induce DC apoptosis and block maturation as a new strategy to prevent GVHD. DC were obtained from PBMN after culture with GM-CSF and IL-4 and were stimulated to maturate and express costimulatory molecules (CD80, CD83, CD86, CD40L) adding TNF and LPS. Even after this stimulation, B at doses ranging from 10 to 50 nM was able to decrease costimulatory molecules as well as HLA-DR expression, as assessed by flow cytometry. In addition, at 50 nM, B increased DC apoptosis (2650 vs 1404 anex/7AAD positive events among DC cultured with or w/o B, respectively; p=0.05). Moreover, B significantly decreased the production of IL-12, while IL10 secretion was unaffected (1,4% vs 6,2% DC cultured with or w/o B secreting IL-12, respectively; p=0.01). Cytokines and proinflamatory molecules genes expression profiling was also analysed by microarrays in DC cultured with or without B. Finally, after culture with bortezomib, DC were cocultured with T lymphocytes and, interestingly, allogeneic mixed lymphocyte reaction was markedly inhibited also inducing a decrease in Th1 cytokine secretion among T cells.
In conclusion, bortezomib induces apoptosis and decreases DC maturation and cytokine secretion and favours tolerance to alloantigens. This new strategy based on DC therapy supports the use of proteosome inhibitors in the management of GVHD.
Intra-Pathway Inhibition of Upstream (PI3K) and Downstream (mTOR) Kinases Synergistically Induces Apoptosis in AML.
Authors: Zeng Zhihong , Estrov Zeev , Harris David , Giles Frank , Andreeff Michael , Konopleva Marina 
Published: April 2020

Abstract
Constitutive activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway regulates the growth and survival of acute myeloid leukemia (AML). We hypothesized that targeting this pathway with both PI3K and mTOR inhibitors may greatly enhance the effectiveness of these two inhibitors in the treatment of AML. PI3KI1 is a novel PI3K inhibitor that induced apoptosis in AML cell lines and primary AML cells at an IC50 of 5μM. It directly inhibited AKT at Ser473, however had limited effects on pGSK3b and on the mTOR downstream target p70S6K at Thr389. Colony-forming assays demonstrated that PI3KI1 decreased the viability of primary AML samples but spared normal bone marrow progenitor cells. mTOR inhibitor CCI779 inhibited phosphorylation of downstream mTOR targets p70S6K and 4EBP, however showed only minor cytotoxicity to AML cell lines and primary samples, suggesting that inhibition of mTOR signaling is not sufficient to cause growth inhibition in the majority of AML. Combined use of PI3KI1 and CCI779 synergistically induced apoptosis in U937 cells, with a combination index of 0.061±0.02. Western blot analysis demonstrated enhanced suppression of pP70S6K, pAKT and p4EBP1(Thr70) when PI3KI1 and CCI779 were used in combination. In primary AML samples, combined inhibition of PI3K and mTOR pathways enhanced apoptosis induction in 8/12 samples, with true synergistic responses in 3 samples. Importantly, the combination, but not PI3KI1 or CCI779 alone, was able to overcome the growth advantage conferred to AML cell lines or primary AML samples by adherence to bone marrow stromal cells. Taken together, our results indicate that PI3K and mTOR are relevant molecular targets in AML and that intra-pathway inhibition of both, upstream and downstream proteins may be required for maximal inhibition of leukemia cell growth.
A Phase 1 Trial of STA-5312, a Microtubule Inhibitor with a Novel Binding Site, in Hematologic and Solid Malignancies.
Authors: Burris Howard , Abramson Neil , Martel Cynthia L. , Schwartzberg Lee V. , Dooley William , McLeod Matthew W. , Dahl Thomas , Sherman Matthew , Limentani Steven 
Published: April 2020

Abstract
BACKGROUND: STA-5312, an inhibitor of tubulin polymerization, with a binding site distinct from other agents such as vincristine, colchicine, or paclitaxel, is not a P-gp substrate. STA-5312 shows in vitro and in vivo activity against leukemia and a range of solid tumors and prolonged survival in models of chemotherapy-resistant cancer.
METHODS: A phase 1 trial was initiated in patients with advanced hematologic cancers or solid tumors to determine the safety, toxicity, pharmacokinetics (PK) and maximum tolerated dose (MTD) of STA-5312. Assessment of activity is a secondary objective. STA-5312 is administered iv on days 1, 3 and 5 of a two week cycle. Dose escalation is based on evaluation of toxicity through the first 3 weeks on the study. In the absence of grade (gr) 2 or greater toxicity, 100% escalations are made. If gr 2 or greater toxicity occurs, all future cohorts are expanded to 3 patients, and further escalations limited to 50%. In the event of any dose limiting toxicity (DLT), the cohort is expanded to 6 patients and escalations limited to 33%. The dose below the lowest dose at which 1/3 of 6 or more patients show DLT will be declared the MTD and expanded to at least 12 patients. PK samples were obtained throughout day 1, and trough and peak samples were taken on day 5. Response is assessed by NCI Working Group Response Criteria, International Workshop Response Criteria Recommendations, or RECIST as appropriate.
RESULTS: After an initial cohort of 3 patients at the dose level of 3 mg/m2 the dose was successively doubled up to 48 mg/m2 with one patient cohorts. At escalation from 48 mg/m2, only a 50% dose increase was made, as exposures were approaching those where significant toxicity was seen in animals. A DLT (hospitalization with dehydration and thrush, liver enzyme elevations and prolonged neutropenia) was reported for the first patient at 72 mg/m2. Two additional patients were added at a dose of 48 mg/m2 and to date no gr 2 toxicities have been reported during the 21 day evaluation. A cohort has been opened at an intermediate dose (60 mg/m2) and enrollment is ongoing to expand it after DLT (dyspnea) was observed in 1 of 3 patients. Other adverse events attributable to STA-5312 include: fatigue, weakness, decreased sensation and hematuria. STA-5312 exhibited relatively linear PK with regard to AUC. Three patients (2 NHL and 1 multiple myeloma) have experienced durable stable disease, with two patients treated for over 8 months.
CONCLUSIONS: STA-5312 was well tolerated through the first five dose levels, with the few adverse events consistent with microtubule disrupting agents. The patients with durable stable disease are encouraging and planning for Phase 2 clinical trials is underway.
Combination of Proteasome Inhibitor PS 341 (Velcade®) with Histone Acetylase Inhibitor (HDAC) PXD 101 Shows Superior Anti-Myeloma Activity and Inhibits Osteoclastogenesis.
Authors: Lentzsch Suzanne , Anderson Gulsum , Li Cuiling , Belani Chandra P. , Mapara Markus Y. , Roodman David 
Published: April 2020

Abstract
Background: PS 341 has demonstrated activity in multiple myeloma (MM), and PXD 101 is a new HDAC inhibitor, currently being evaluated in Phase II clinical trials for MM. In addition to the anti-myeloma activity of PS 341 and PXD 101, HDAC inhibitors are strong inhibitors of osteoclast formation. Therefore, the combination of the two agents, targeting both the tumor and the development of osteolytic lesions should lead to an optimal treatment strategy for MM.
Methods: MM cell lines (MM.1S, OPM 2, RPMI 8226) were exposed to serial dilutions of PS 341 (1–1000 nM) and PXD 101 (10–1000 nM) for 48 hours. Thymidine uptake was measured to assess inhibition of proliferation. To evaluate the effects of PS 341 and PXD 101 on the formation of osteoclasts from mononuclear hematopoietic precursors, we used a human bone marrow culture system from healthy donors and MM patients to generate osteoclasts using in vitro RANKL/M-CSF stimulation.
Results: Dose-dependent inhibition of proliferation was achieved in all MM cell lines after a 48-hour treatment with PS 341 and PXD 101. For further experiments we used PS 341 at a fixed low concentration (10 nM), which showed no significant inhibition of proliferation of MM cell lines. PXD 101 was used at 100 nM and demonstrated median inhibition of 46% (range 0–48%). The combination of PS 341 with PXD 101 induced synergism with inhibition of proliferation of median 73% (range 44–73%). Although 100 nM PXD 101 and 50 nM PS 341 used as single agents were required to inhibit the proliferation of MM cells, combination of 25 nM PXD 101 and 1 nM PS 341 was sufficient to inhibit OCL formation completely, indicating that the drug combination results also in a highly synergistic inhibition of osteoclast formation.
Conclusions: These studies provide the framework for clinical evaluation of PS 341 combined with PXD 101 in patients with MM and supports the hypothesis that the drug combination targets both the tumor and osteoclastic activity. (Drugs provided by NIH/NCI; Support: UO1 CA099168)
Factor V Level Affects the Host Susceptibility to Group A Streptococcal Infection.
Authors: Sun Hongmin , Yang Angela , Wang Xixi , Ginsburg David 
Published: April 2020

Abstract
Group A streptococci (GAS), a common human pathogen, secrete streptokinase (SK), which activates the host’s plasminogen (PLG). SK is highly specific for human PLG, exhibiting little or no activity against other mammalian species. We demonstrated the major role of the PLG/SK interaction in GAS pathogenicity using a transgenic murine model expressing human plasminogen with increased susceptibility to human pathogenic streptococci. We hypothesize that GAS hijack the host fibrinolytic system in order to circumvent local thrombosis for systemic spread. Markedly increased mortality was also observed following GAS injection in C57BL/6J mice treated with the snake venom Ancrod, which proteolytically degrades plasma fibrinogen, supporting the critical roles of coagulation in host/pathogen interaction.
However, fibrinogen also plays important roles in inflammation and immune response, it is necessary to use independent genetic models to further test the impact of coagulation in host defense against bacterial infection. The effect of variations in FV on mouse susceptibility to streptococcal infection was tested. We established a mouse model with low plasma FV level. These mice have a slightly increased bleeding time, though otherwise phenotypically normal. Subjected to streptococcal infection, these mice exhibited significantly increased mortality than wildtype controls, suggesting that the decreased thrombotic tendency in the low FV mice increases host susceptibility to infection. FV Leiden is a common prothrombotic mutation among Caucasian population with an incidence between 4% and 6%. Previous studies from Kerlin et al demonstrated the FV Leiden conferred survival advantage in patients with severe sepsis and in mice challenged with endotoxin. This may be an example of balanced gene polymorphism that maintains the FV Leiden mutant in the general gene pool by selection of bacterial infections. In order to identify the selective agents responsible for the prevalence of FV Leiden mutation, we took advantage of our plasminogen transgenic murine model for streptococcal infection to test whether streptococci is one of the selective agents. Human plasminogen transgene was introduced into FV Leiden background and the susceptibility to streptococcal infection was measured. No significant improvement of survival was observed in the FV Leiden mouse comparing with the wildtype control. Thus, streptococcal infection is not the selective agent for the prevalence of FV Leiden mutation.
These observations highlight the potential role of variations in blood coagulation factors in host susceptibility to bacterial infection.
Hematologic Improvement (HI) by TLK199 (Telintra™), a Novel Glutathione Analog, in Myelodysplastic Syndrome: Phase 2 Study Results.
Authors: Raza Azra , Callander Natalie , Ochoa Leonel , Piro Lawrence , Emanuel Peter , Guba Susan , Shapiro Gabriel , Williams Stephanie , Burris Howard , Faderl Stefan , Estrov Zeev , Curtain Peter , Larson Richard , Young Shelby , Brown Gail L. 
Published: April 2020

Abstract
Introduction: Glutathione S-transferase (GST) P1-1 has shown to be an important negative regulator of cellular growth and differentiation. The effect is mediated through binding to Jun kinase (JNK) which causes a decrease in kinase activity. TLK199, a novel analog of glutathione, binds selectively to GSTP1-1 resulting in its dissociation from JNK and subsequent kinase activation. Exposure of hematopoietic progenitor cells to TLK199 led to activation of JNK followed by cellular growth and maturation. TLK199 has shown significant myelostimulant activity in vitro in human bone marrow cell cultures as well as in several in vivo preclinical models of myelopoeisis. In Phase 1, TLK199 treatment resulted in hematologic improvement (HI) in MDS patients at all dose levels.
Methods: The objectives of this multicenter Phase 2 study in MDS were to determine the safety (by NCI-CTC) and efficacy (by modified IWG MDS response criteria) of two dose schedules of TLK199 HCl Liposomes for Injection administered at 600 mg/m2 over 60 minutes by constant rate IV infusion daily x 3 or daily x 5 every 3 weeks. Patients (pts) were treated until lack of response or unacceptable toxicity.
Results: 52 MDS pts (33 M/19 F),(29 RA, 9 RARS, 8 RAEB, 3 RAEB-t, 1 CMML, 2 UK), median age 69 years (range 22–90), received 244+ cycles (1099+ treatments), median 4 (range 1–13+). Thirty-seven pts (71%) were red cell transfusion dependent and 10 pts (19%) were platelet transfusion dependent prior to entry. Pts had failed a median of 1 prior therapy (range 0–6) including: erythropoietin (27/52%), G-CSF (9/17%), thalidomide (10/19%), azacitidine (7/14%), steroids (6/12%), hormones (2/4%), and other therapies (14/27%). Thirty-nine pts were evaluable for efficacy, 32 pts (82%) experienced HI in one or more blood cell lineages, 14 of 16 pts (88%) with trilineage dysfunction, 8 of 13 pts (62%) with bilineage dysfunction, and all 10 pts (100%) with unilineage dysfunction experienced HI. Lineage response was HI-P (14 of 22/64%), HI-N (9 of 27/33%), and HI-E (22 of 35/63%). Responses were accompanied by clinical symptom improvement, decreases in RBC and platelet transfusion requirements including transfusion independence and improvements in bone marrow maturation, differentiation, M/E ratios, and dysplastic morphology. Most common adverse events were mild to moderate acute infusion related reactions commonly seen with liposomal formulations: back pain (9/17%), nausea (8/15%), chills (8/15%), and bone pain (6/12%).
Conclusions: TLK199 is well tolerated and an active agent in all FAB types of MDS. These data support the further clinical development of TLK199 in MDS as well as in other hematologic malignancies characterized by cytopenias.
Long-Term Follow-Up Results of the Combination of Topotecan and Cytarabine and Other Intensive Chemotherapy Regimens in Myelodysplastic Syndrome.
Authors: Jabbour Elias , Kantarjian Hagop , Beran Miloslav , Cortes Jorge , O’Brien Susan , Giles Francis , Pierce Sherry , Shan Jianqin , Plunkett William , Keating Michael , Estey Elihu 
Published: April 2020

Abstract
Background. Higher-risk myelodysplastic syndrome (MDS) is often treated with intensive chemotherapy regimens used for acute myelogenous leukemia (AML). Patients with MDS are often older and may have contraindications to anthracycline-based regimens. Topotecan-cytarabine regimens had shown encouraging results in higher-risk MDS.
Study aims. To analyze the long-term results with topotecan-cytarabine versus other intensive chemotherapy regimens in higher-risk MDS.
Study Groups and Methods. 510 patients with higher-risk MDS (marrow blasts ≥ 10%) treated with intensive chemotherapy were reviewed. Median age was 63 years; 82% had intermediate 2 or high risk MDS; 52% had secondary MDS; 40% had chromosome 5 or 7 abnormalities. Therapy was: topotecan-cytarabine in 77; idarubicin-cytarabine regimens in 270; topotecan-cytarabine and cyclophosphamide in 67; fludarabine-cytarabine in 96. Univariate and multivariate analyses were conducted to evaluate the independent associations of different variables, and most importantly the treatment regimen, with complete response, induction, mortality, and survival.
Results. The overall CR rate was 55%, induction mortality 20%, and 5-year survival rate 8%. The 5-year survival rate was 11% for patients younger than 65 years old, and 17% for patients with a normal karyotype. Among 82 patients younger than 65 years with a normal karyotype, the CR rate was 67%, 5-year survival rate 27%, and 5-year CR duration rate 33%. Topotecan-cytarabine regimens were equivalent to idarubicin-cytarabine regimens in relation to CR rates and survival rates, but were associated with a lower induction mortality. Multivariate analysis confirmed that treatment regimens were not associated with independent significant differences in CR rates or survival. However, topotecan-cytarabine regimens were still selected to be associated with lower induction mortality rates.
Conclusions. Topotecan-cytarabine regimens are equally effective to other AML regimens in higher-risk MDS and may be less toxic. Topotecan-cytarabine should be considered as a reasonable alternative to idarubicin-cytarabine in higher-risk MDS, particularly in older patients with contraindications to anthracyclines.