bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Screen In Primary Erythroblasts Reveals a MicroRNA-Centered Homeostatic Mechanism for Regulating Cyclin E Activity.
Authors: Xu Yanfei , Sengupta Tanushri , Minella Alexander C. 
Published: October 2019

Abstract
Abstract 1543
A growing body of evidence highlights the importance of microRNAs in regulating the expression of mediators of cell cycle progression. A theme emerging from these studies is that microRNAs participate in feedback or feed-forward circuits to provide bistability for key transition points in the cell cycle. We previously have shown that proper regulation of cyclin E activity is required for normal erythroid cell maturation in vivo, using cyclin ET74AüT393A knock-in mice, which have markedly dysregulated cyclin E due to its failure to interact with the Fbw7 ubiquitin ligase complex. We hypothesized that we could identify novel, microRNA-based molecular circuitry for maintaining appropriate levels of cyclin E activity by screening cyclin E knock-in erythroblasts for alterations in microRNA expression. We analyzed data we obtained from multiplex real-time PCR arrays comparing the expression of over 500 microRNAs in cyclin ET74A T393A knock-in versus wild-type erythroblasts (Ter119+/CD71+) and found down-regulated expression of a number of microRNAs targeting CDK inhibitors. We also identified down-regulated expression of potential microRNA regulators of Fbw7 expression. We found that overexpression of miR-223, in particular, significantly reduces Fbw7 mRNA levels, increases endogenous cyclin E protein and activity levels, and increases genomic instability. We next confirmed that miR-223 targets the Fbw7 3’ untranslated region. We then found that reduced miR-223 expression leads to increased Fbw7 expression and decreased cyclin E activity. Finally, we found that miR-223 expression in K562 cells is responsive to acute alterations in cyclin E regulation by the Fbw7 pathway and that dysregulated Fbw7 expression alters the erythroid differentiation capacity of these cells. Mir-223 plays an important role in myeloid and erythroid differentiation by regulating multiple substrates involved in these maturation programs. Here, we identify Fbw7 as a novel target of miR-223. Our data also indicate that miR-223 modulates Fbw7 expression as part of a homeostatic mechanism to regulate cyclin E activity and provide the first evidence that activity of the SCFFbw7 ubiquitin ligase can be controlled by the microRNA pathway.

Disclosures:
No relevant conflicts of interest to declare.
Small Rab GTPase Rab7b Promotes Megakaryocytic Differentiation by Enhancing IL-6 Production and STAT3-GATA-1 Association.
Authors: He Donghua , Chen Taoyong , Yang Mingjing , Zhu Xuhui , Cao Xuetao , Cai Zhen 
Published: October 2019

Abstract
Abstract 1549
Interleukin 6 (IL-6) is a pleiotropic cytokine acting on a variety of cell types, and plays important roles in hematopoiesis. GATA-1 (GATA binding protein 1) is an important transcription factor involved in either megakaryocytic or erythrocytic differentiation. However, the mechanisms for IL-6-induced megakaryocytic differentiation and regulation of GATA-1 have not been fully elucidated. By using phorbol-12-myristate-13-acetate (PMA)-induced megakaryocytic differentiation of K562 cells as a model, we investigated the roles of Rab7b, a late endosome/lysosome-localized myeloid small GTPase, in megakaryocytic differentiation. We find that Rab7b can promote PMA-induced megakaryocytic differentiation, as evidenced by typical morphological alterations, increased fibronectin-specific adhesion, increased polyploidy formation, and increased expression of CD41a. The GTP-bound status and lysosomal localization of Rab7b are required for promotion of K562 megakaryocytic differentiation, which can be blocked by inhibitor of nuclear factor κB (NF-κB) and neutralizing antibodies for IL-6 and gp130. In Rab7b-silenced K562 cells, PMA-induced activation of NF-κB, IL-6 production and megakaryocytic differentiation are impaired. Furthermore, we demonstrate that IL-6-induced activation of signal transducer and activator of transcription 3 (STAT3) and the subsequent association of STAT3 with GATA-1 may contribute to PMA-induced and Rab7b-mediated transcriptional upregulation of megakaryocytic differentiation markers. Therefore, our data suggest that Rab7b may play important roles in megakaryopoiesis by activating NF-κB and promoting IL-6 production. Our study also indicates that the IL-6-induced association of STAT3 with GATA-1 may favor megakaryopoiesis.

Disclosures:
No relevant conflicts of interest to declare.
Klotho Polymorphisms and Priapism In Sickle Cell Disease.
Authors: Souza Claudia R Lustosa , Shimmoto Marily M Azevedo , Vicari Perla , Arruda Martha Mariana A S , Roizenblatt Marina , Pedro Ana C Cabanas , Hayashida Debora Y , Mecabo Grazielle , Figueiredo Maria Stella 
Published: October 2019

Abstract
Abstract 1653

Background:
Sickle cell disease (SCD) is a monogenic disorder with phenotypic heterogeneity, possibly determined by polymorphisms (SNPs) in genes whose products modify the pathophysiology of the disease. Priapism is one of the most common vaso-occlusive complications of SCD, and it occurred in more than 30% of males. The Klotho (KL) gene appears to be associated with vascular function and nitric oxide biology and the presence of SNPs could affect its function. Association between KL and priapism in SCD patients was suggested by Nolan et al. in 2004. However, other authors could not confirm this finding (Elliot et al., 2007).

Objective:
We decided to evaluate the relevance of SNPs rs2249358, rs211234 and rs9536314 to the occurrence of priapism in patients with SCD followed at Outpatient clinic at Escola Paulista de Medicina/UNIFESP.

Methods:
Forty male patients with SCD were enrolled, 39 (97.5%) with sickle cell anemia (SS) and one (2.5%) SC hemoglobinopathy. The manifestation of priapism was identified through analyses of medical records. The SNP rs2249358 was identified by PCR followed by restriction with XbaI. The other SNPs, rs211234 and rs9536314, were analyzed by allele specific PCR. Statistical analysis: t test, Chi2 or Fisher. This study was approved by Ethical Committee, and all patients agreed in participate.

Results:
The median age of the patient was 28.5 years-old (20-68 y.o.). Fourteen out of 40 patients had priapism (35%), each one with SS disease. The group of patients with priapism were older (32.5 y.o., 25–68 y.o.) than the group without this manifestation (27.5 y.o., 20–56 y.o.) (p=0.03). There was no statistical difference in the distribution of the SNPs rs211234 and rs9536314 between the two groups of patients (p=0.51 and p= 0.09, respectively). Regarding the distribution of SNP rs2249358, the group with priapism presented 8 individuals (57.1%) with GG genotype, 5 (35.7%) with AA and 1 (7.17%) with AG, whereas in the group without priapism, the distribution was different: 5 (19.2%) with GG, 7 (26.9%) with AA and 14 (53.8%) with AG genotype (p=0.0212). When we compare the presence of at least one A allele (AA or A-) with the G allele in homozygosis (GG), we observed that the A allele has a protector effect (OR: 0.1786; CI: 0.04232–0.7535) (p=0.031).

Conclusions:
In a relatively small group of patients with SCD, it was observed a significant proportion of individuals with priapism, which reinforces the importance of this manifestation. We also observed correlation between SNP rs2249358 of KL gene and priapism, as suggested previously.

Disclosures:
No relevant conflicts of interest to declare.
DIGE-Based Proteomic Analysis Identifies NPM/B23 and Nucleolin C23 as Overexpressed Proteins In Relapsed /Refractory Acute Leukemia
Authors: Hu Jian Da , Lin MinHui , Liu TingBo , Li Jing , Chen XinJi , Chen BuYuan 
Published: October 2019

Abstract
Abstract 1711
Resistance to chemotherapy is a challenge in treatment of acute leukemia. Although the classic multidrug resistance (MDR) phenotype is often characterized by expression of drug efflux pump P-glycoprotein or by multidrug resistance-associated proteins, precise molecular mechanisms are largely unknown. To investigate novel protein changes involved in resistance mechanism, protein expression profiles between human myeloid leukemia HL-60 cell lines and adriamycin- resistant HL-60 cell lines (HL-60/ADR) was compared, which was based on a differential proteomic approach — 2 dimensional difference in gel Electrophoresis(2D-DIGE) followed by mass spectrometry (MALDI-TOF-MS) and complemented by western blot validation. 16 protein spots were identified as being differentially expressed (> 1.2 fold change and p≤ 0.05) between above two cell lines, among which 13 protein spots were identified as up-regulated and 3 as down-regulated in the HL-60/ ADR cell line. Proteins found to have higher abundance levels in the resistant HL-60/ADR cells included enzymes, proteins and oncogenes related to signal transduction, protein synthesis, cell growth regulation and metabolism. 3 lower abundance proteins are related to transcription. From 16 proteins, 2 proteins, nucleophosmin B23 (NPM B23)and nucleolin C23, were selected and verified in leukemia cell lines and primary leukemia samples by western blot. Compared to healthy control samples, which showed no expressions of these 2 proteins, leukemic cell lines revealed an obvious up-regulation of B23 and C23. Moreover, significantly higher expressions of B23 and C23 were found in 3 resistant leukemic cell lines, HL-60/ADR, K562/ADR and KG01 cells, compared to the parent HL-60 and K562 cells, and other leukemic cell lines. In de novo leukemia samples, 43.8%(35/80) expressed B23 and C23 proteins, 37.9% (22/58) AML and 59.1% (13/22) ALL respectively. Meanwhile, concomitant expression of B23 and C23, both positive or negative, was noted in 97%(79/80)patients. Over-expressions of B23 and C23 were observed in 68.8% relapased/refractory leukemia patients. With regard to treatment outcome,among those patients who achieved ongoing CR, fewer patients expressed 2 proteins, only 13.35% (7/52) AML and 46%(7/15) ALL respectively. It implicated that B23 and C23 may be involved in drug resistance and be useful in assessing treatment outcome and prognosis of leukemia. To a conclusion, these results provide a novel clue for the molecular mechanism of MDR and suggest that B23 and C23 are prognostic indicators for leukemia.

Disclosures:
No relevant conflicts of interest to declare.
Single 4.5mg Dose of Rasburicase for Tumor Lysis Syndrome In Adults
Authors: Yim Barbara , Navaleza Anne , Haidau Augustin , Sreenivasappa Shylendra , Kassem Mohammed A. , Ciobanu Bety C. , Braik Tareq , Gaddh Manila , Rubinstein Paul G. , Shah Moushmi , Telfer Margaret , Catchatourian Rose 
Published: October 2019

Abstract
Abstract 1779

Introduction:
Tumor Lysis Syndrome (TLS) is an oncologic emergency that leads to a host of metabolic disturbances which can ultimately result in acute renal failure and death.
Currently rasburicase, Elitek™, is FDA approved for the treatment of TLS in patients with leukemia, lymphoma, and solid tumor malignancies which have risk factors for TLS. The approved adult dose is 0.2mg/kg/day over 30 minutes for up to 5 days. Chemotherapy should be initiated within 24 hours of rasburicase administration. Since rasburicase's introduction to the market, various studies have examined single dose use (3mg and 6mg) in the adult population, trying to resolve the dilemma of determining a dosing regimen for adults that is as effective as the FDA approved dosing regimen, while minimizing cost.
This study was aimed at determining if a single 4.5mg dose of rasburicase would be adequate in reducing uric acid levels (UAL) as compared to the FDA approved conventional weight based approach; it also sought to determine the cost-effectiveness of this approach.

Method:
This is a retrospective study of the John H. Stroger Jr. Hospital of Cook County (JHS) patients who were administered a single dose of 4.5 mg rasburicase for TLS from 12/2007 to 06/2010. We included patients ≥ 18 years old, with a hematologic malignancy and on chemotherapy or about to start receiving chemotherapy within 24 hours of rasburicase administration. Patients with low risk for TLS or an indication other than prevention and management of TLS were excluded.

Result:
Demographics:
Characteristics:
Responders are defined as patients that achieved more than 50% reduction in the UAL at 24 hours, 48 hours or 96 hours or a decrease of UAL to normal levels. Two patients required a second dose to achieve response. The non-responders did not receive any additional doses for unclear reasons. No adverse events were noted.

Conclusion:
This retrospective study provides evidence that a single 4.5mg dose of rasburicase effectively reduced plasma UAL to within normal limits. In addition, decrease in plasma UAL was observed within 24 hours after administration. No effect on electrolytes and serum creatinine was noted.
The cost-effectiveness of a single 4.5mg dose of rasburicase was evaluated based on dose and drug cost. The potential cost saving was substantial when compared with the FDA approved dose.
In our opinion, this study validates the use of a single dose of 4.5mg rasburicase in the treatment and prophylaxis of TLS. This dose can be considered as a possible alternative to the FDA approved adult dosing regimen.

Disclosures:
No relevant conflicts of interest to declare.
Fludarabine Plus I-131 Tositumomab as Initial Treatment for Follicular Lymphoma: Half of Patients In Remission at Over 10 Years Median Followup.
Authors: Martin Peter , Coleman Morton , Furman Richard R. , Vallabhajosula Shankar , Kim Dong Sun , Edelstein Andrew , Morrison Julia , Elstrom Rebecca , Ruan Jia , Goldsmith Stanley J. , Leonard John P. 
Published: October 2019

Abstract
Abstract 1785

Background:
The sequential combination of chemotherapy and radioimmunotherapy has been shown to be effective front-line treatment for patients with follicular lymphoma (FL). We report ten-year followup results of a phase II trial of abbreviated fludarabine followed by tositumomab and I-131 tositumomab in patients with untreated follicular lymphoma.

Methods:
Patients with untreated follicular lymphoma received fludarabine 25 mg/m2/d for five days every five weeks for three cycles followed in six to eight weeks by tositumomab and I-131 tositumomab.

Results:
Thirty-eight patients were enrolled. One patient was withdrawn due to ineligible histology. The median age of eligible patients was 53 years, median time from diagnosis was 3.5 months, and 43% of patients had a high-risk FLIPI score. Two patients did not receive radioimmunotherapy; one patient had a myocardial infarction during fludarabine and was not evaluable, and one patient had persistent cytopenias following three cycles of fludarabine. All 35 patients that completed the regimen responded (ORR 100%). With a median follow-up of 128.5 months for all 37 eligible patients, the 10-year intent-to-treat overall survival is 69% and the progression-free survival is 51%. Seventeen patients have progressed (range 2–102 months). Sixteen patients remain in remission with no evidence of disease more than ten years from enrollment. Only four patients have relapsed beyond five years. Four patients have developed MDS (range 16–84 months), one of whom evolved to AML.

Conclusions:
Fludarabine followed by tositumomab and I-131 tositumomab is very effective at inducing long-lasting complete remissions in FL. The efficacy and long-term safety of sequential chemotherapy plus radioimmunotherapy should continue to be evaluated in the context of the range of therapeutic options for the initial treatment of follicular lymphoma.

Disclosures:
Furman: GSK: Speakers Bureau. Leonard:GSK: Consultancy.
Age-Dependent Influence of TNF-α Polymorphism on Progression Free Survival of ASCT In Multiple Myeloma Patients
Authors: Buda Gabriele , Martino Alessandro , Orciuolo Enrico , Maggini Valentina , Lapi Francesco , Galimberti Sara , Barale Roberto , Rossi Anna Maria , Petrini Mario 
Published: October 2019

Abstract
Abstract 1829

Proinflammatory cytokines are suspected to play a role in the pathogenesis of multiple myeloma (MM). TNF-a, a potent mediator of inflammation, is involved in the malignant transformation of plasma cells and plasma cell proliferation. TNF-a determination was also reported to be a good parameter for monitoring therapy outcome during treatment with different protocols. Variation in TNF-a levels can be related to gene expression, which is regulated at transcriptional level, as well as to genetic polymorphism (SNP). Specifically, a G to A substitution at position -308 is associated with higher levels of TNF-a.
From September 2006 to April 2010 we selected 202 MM patients and 234 control cases matched for age and sex. TNF-a SNP at position -308 was determined on genomic DNA extracted from blood samples. These genotypes frequencies obtained were in Hardy-Weinberg equilibrium. Our results indicate that the cytokine TNF-a gene SNP do not confer differences in the susceptibility of MM. Then, we studied the correlation between the SNPs of TNF-a -308 and the outcome of 91 MM patients that underwent to autologous bone marrow transplantation (ASCT) after a similar induction therapy (DAV or TAD). Melphalan 200 mg/mq (or 100 mg/mq, for the elderly patients) was used as conditioning regimen (table I).
In the MM carrying the rarest A allele of TNF-a the overall response to chemotherapy and outcome to ASCT were similar to patients carriers G allele. On the contrary TNF-a seems to be an independent factor to predict the outcome in patients affected by MM modifying the progression free survival age related, if patients are > 60 yrs (p= 0.02). In particular pts > 60 years carrying the G/G genotype showed a better progression free survival compared to the same age patients carrying A/A or G/A genotypes (table II and table III ). Previous studies demonstrated that an higher plasma TNF-a concentration is significantly associated with advancing age and the combination of TNF-a and melphalan results in high response rates. Several mechanisms could be responsible for this, in particular a direct effect of TNF-a on the anti-tumour activity of melphalan. In our population the high dose of melphalan used in the youngest population is able to mask the role of TNF-a, but in the elderly patients it is clear as the impact of polymorphism plays a role in the better PFS of patients carrying the G/G genotype. To conclude we confirm the interesting role of TNF-a SNP in the outcome of MM in particular in the subset of pts characterized by a physiological high production of TNF-a.

Disclosures:
No relevant conflicts of interest to declare.
The BH3 Mimetic, ABT-737, Overcomes Stromal-Mediated Pro-Survival Signals and Synergizes with PHA-767491, a Dual Cdc7/CDK9 Inhibitor, In Acute Myeloid Leukaemia
Authors: Morrell Ruth C , Szegezdi Eva , Halpin-McCormick Anna , Cawley Karen , Samali Afshin , O'Dwyer Michael 
Published: October 2019

Abstract
Abstract 1841
ABT-737 is a small molecule inhibitor of Bcl-2 and Bcl-xL with reported activity in pre-clinical in-vitro and in-vivo studies of acute myeloid leukaemia(AML) but to date no data has been reported on its activity in an AML co-culture model. To address this, we examined the effects of co-culture of AML cell lines (MOLM-13, ML-1, KG-1, OCI-AML2) with HS5 cells, a human stromal cell line, on sensitivity to Ara-C and ABT-737. All cell lines cultured in the presence of HS-5 stroma demonstrated a significant reduction in Ara-C-induced apoptosis (% relative reduction - OCI-AML2:80%; ML1:65%; MOLM-13:53%; KG-1:55%) as compared to cells cultured in suspension in normal complete media, with the effect on expression of Bcl-2 family members being currently under evaluation. In contrast, in the presence of ABT-737, HS-5 co-culture did not provide any protective effect whatsoever to AML cells, with IC50 ranging from 0.1 to 0.3μM in the cell lines noted above, regardless of the presence of stroma. OCI-AML3, an AML cell line known to express high levels of Mcl-1 was resistant to ABT-737 in both normal suspension cultures and co-culture. Indeed Mcl-1, an important pro-survival protein in haematopoietic cells is thought to be a key factor promoting resistance to ABT-737 and it has recently been reported that transcriptional upregulation of Mcl-1 may follow exposure to ABT-737. Thus, the combination of ABT-737 with strategies to deplete Mcl-1 is particularly attractive. Cdk9 inhibition is such a strategy. Since Cdk9 phosphorylates RNA polymerase II affecting the rate of transcription, inhibition leads to a depletion of proteins with short half-lives, such as Mcl-1. Here we report that resistance of OCI-AML3 cells to ABT-737-induced apoptosis can be overcome by combination with PHA-767491, a novel dual Cdc7/CDK9 inhibitor. OCI-AML3 cells were treated with increasing concentrations of ABT-737, PHA-767491 or both. Co-administration resulted in a strong synergistic apoptosis-inducing effect as assessed by AnnexinV staining, with combination indices, as calculated by Chou et Talalay, for a range of doses of both drugs of <1 (range 0.3–0.9). Importantly, the sensitising effect of PHA-767491 was seen only at concentrations (≥ 2μM) that resulted in significant downregulation of Mcl-1 protein expression, implicating Mcl-1 downregulation as a possible cause of synergy. We are currently investigating the precise role of Mcl-1 in this regard. In conclusion, taken together, these studies support that ABT-737, possibly in combination with agents to deplete Mcl-1, represents a promising therapeutic strategy for AML and warrants further evaluation.

Disclosures:
No relevant conflicts of interest to declare.