bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of Potential Chemosensitivity Genes in Multiple Myeloma
Authors: Yang Lin , Zhang Xingding , Wang Hua , Orlowski Robert Z. , Huang Xingxu 
Published: October 2019

Abstract
Abstract 1818
Chemotherapy agents are extremely important in the treatment of liquid malignancies, such as multiple myeloma (MM). Unfortunately, chemotherapy resistance in MM therapy is the most significant cause of treatment failure. The ability to predict, treat, or circumvent resistance is extremely likely to improve clinical outcomes. Thus, identification of novel genes that play a crucial role in MM progression and chemosensitivity is necessary to understand this disease better at the molecular level. Moreover, these genes and their products may serve as new therapeutic targets for MM, whose expression could improve patient outcomes or served as a predictor for chemotherapy outcome. To identify potential chemosensitivity genes, establishing a high-throughput method for validation of targets becomes urgently needed. Toward this purpose, we have successfully developed a high-throughput siRNA based functional target validation approach and identified 34 potential chemosensitivity genes.
Our preliminary studies focusing on one of the candidate gene, TJP1 (tight junction protein 1), suggested that targeting TJP1 led to tumor cell resistant to several chemotherapy agents, including doxorubicin (Dox), cisplatin (Cis), methotrexate (MTX), and bortezomib. Further analysis with 264 bortezomib treated MM patients indicated that expression level of TJP1 correlated with patient response to bortezomib. Two clones and pooled RPMI 8226 MM cell line, which were developed against bortezomib treatment in our lab, showed loss of TJP1 expression, suggesting a role of TJP1 may play in bortezomib resistance development. More importantly, TJP1 targeting in myeloma cells resulted in cell resistance to bortezomib treatment.
Protein tyrosine phosphatase, receptor type, O1 (PTRPO) was identified in our screening as well. We first examined the expression of PTPRO in a panel of myeloma cell lines, and found that PTPRO expression was dramatically decreased in several drug resistant lines compared to their parental sensitive cells. Moreover, using a Lentiviral cDNA expression system to overexpress PTPRO, we observed that PTPRO significantly inhibited cell growth and sensitized drug sensitivity of several drug lines by triggering apoptosis. Finally, evaluation of the publicly available gene expression profiling data gathered from primary plasma cells on the Multiple Myeloma Genomics Portal, and the linked clinical annotation describing patient outcomes, has shown that over-expression of PTPRO is associated with a superior overall survival compared to patients whose myeloma show low levels of PTRPO expression, suggesting this may be a prognostic marker as well.
Together, we have successfully identified a group of potential chenmosensitivity genes, in which two of the genes (TJP1 and PTPRO) have been further validated to sensitize the drug treatment in multiple myeloma cells.

Disclosures:
No relevant conflicts of interest to declare.
The New CXCR4 Inhibitor MDX-1338 Exerts Anti-Tumor Activity in Multiple Myeloma
Authors: Roccaro Aldo M , Sacco Antonio , Kuhne Michelle , Azab AbdelKareem , Maiso Patricia , Zhang Yong , Liu Yang , Azab Feda , Issa Ghayas C , Quang Phong , Ngo Hai T , Pan Chin , Choen Lew , Cardarelli Pina M , Ghobrial Irene M. 
Published: October 2019

Abstract
Abstract 1844

Background.
We have previously shown the SDF1/CXCR4 axis plays a major role in homing and trafficking of multiple myeloma (MM) to the bone marrow (BM), and disruption of the interaction of tumor cells with the BM leads to enhanced sensitivity to therapeutic agents. We hypothesize that the novel anti-CXCR4 antibody, BMS936564/MDX-1338, may prevent the homing and adhesion of MM cells to the BM and will sensitize them to therapeutic agents.

Methods.
Primary MM cells (CD138+); MM cell lines (MM.1S, RPMI.8226); and primary MM bone marrow stromal cells (BMSCs) were used. Migration towards SDF-1 and BMSCs has been evaluated. Cytotoxicity and DNA synthesis were measured by MTT and thymidine uptake, respectively. Cell signaling and apoptotic pathways were studied by Western Blot. Synergism was calculated using the Chou-Talalay method. In vivo MM tumor growth was evaluated with xenograft mouse models.

Results.
MDX-1338 inhibited migration of MM cells toward SDF-1a and primary MM BMSCs, in a dose-dependent manner. Adhesion of primary MM cells to BMSCs was also inhibited by BMS936564/MDX-1338 in a dose-dependent manner, while also inducing cytotoxicity on primary BM-derived CD138+ cells. BMS936564/MDX-1338 targeted MM cells in the context of BM milieu by overcoming BMSC-induced proliferation of tumor cells. In addition, BMS936564/MDX-1338 synergistically enhanced bortezomib-induced cytotoxicity in MM cells. BMS936564/MDX-1338-dependent activation of apoptotic pathways in MM cells was documented, as shown by cleavage of caspase-9 and PARP. SDF-1a-induced ERK-, Akt-, and Src-phosphorilation was inhibited by BMS936564/MDX-1338 in a dose-dependent manner. Importantly, BMS936564/MDX-1338 inhibited MM cell proliferation in vivo in xenograft mouse models.

Conclusion.
These studies therefore show that targeting CXCR-4 in MM by using BMS936564/MDX-1338 represents a valid therapeutic strategy in this disease.

Disclosures:
Roccaro: Roche:. Kuhne:BMS: Employment. Pan:Bristol-Myers Squibb: Employment. Cardarelli:Bristol-Myers Squibb: Employment. Ghobrial:Noxxon: Research Funding; Bristol-Myers Squibb: Research Funding; Millennium: Research Funding; Noxxon:; Millennium:; Celegene:; Novartis:.
Bortezomib Induction Followed by ASCT in Patients with Multiple Myeloma: Achievement of Response After Induction and Achieving CR Post-ASCT Are Both Important Prognostic Markers
Authors: Kim Min Kyoung , Min Chang-Ki , Hyun Myung Soo , Kim Kihyun , Yoon Sung-Soo , Kim Jin Seok , Eom Hyeon Seok , Suh Cheolwon , Kang Hye Jin , Kim Jeong-A , Mun Yeung-Chul , Shin Ho-Jin , Jo Deog-Yeon , Choi Chul Won , Moon Joon Ho , Kim Yang Soo , Yang Deok-Hwan , Bae Sung Hwa , Lee Gyeong-Won , Kwon Jung Hye , Kim Kyoung Ha , Yoon Hwi-Joong , Kim Chul Soo , Park Joon Seong , Lee Jae Hoon 
Published: October 2019

Abstract
Abstract 1866

Background:
In multiple myeloma (MM), the association between the response to induction before autologous stem cell transplantation (ASCT) and long-term outcome is less clear but the situation may change with the introduction of novel agents. We therefore assessed the clinical relevance of response of bortezomib induction treatment or post-ASCT response for patients who received bortezomib-combined induction chemotherapy followed by ASCT.

Methods:
We retrospectively assessed 183 MM patients who received bortezomib-containing induction therapy (BTZ-IT) followed by ASCT in 24 institutions throughout Korea between 2003 and 2010. Records of these patients were reviewed using the Korean Myeloma Registry database (www.myeloma.or.kr). Each institution was requested to reconfirm the data using additional case report forms. Patients who had overt MM based on International Myeloma Working Group diagnostic criteria were selected.

Results:
One-hundred seventy eight patients were eligible. Their median age was 56 years (range, 28–69 years) and 96 (53.9%) were male. Forty nine (27.5%) received bortezomib as front-line therapy and 129 (72.5%) as second-line treatment. All patients underwent ASCT and 22 (12.4%) were treated with tandem ASCT. Ninety-seven (54.5%) patients were treated with maintenance therapy after ASCT. After BTZ-IT, the response rates in this selected series of patients were 37.6% CR, 12.4% VGPR, 41.0% PR, 7.3% SD and 1.7% PD (Figure 1A, 1B, 1C); the corresponding post-ASCT rates were 69.2% CR, 14.0% VGPR, 11.0% PR, 2.9% SD and 2.9% PD. At a median follow-up of 46.6 months, the 3-year overall survival (OS) and event-free survival (EFS) rates were 70.0% and 31.9%, respectively. Multivariate analysis showed that factors independently predictive of OS and EFS included achievement of BTZ-IT response °Ã PR (P=0.025 and P=0.014, respectively) and the treatment with maintenance therapy (P=0.048 and P=0.001, respectively). Post-ASCT CR vs. °Â VGPR was also an independent prognostic factor for OS and EFS (P=0.0001 and P=0.002, respectively).

Conclusion:
At least PR to BTZ-IT and CR after ASCT were predictive of survival. These findings suggest that patients who responded to BTZ-IT may benefit from ASCT due to an enhanced quality of response. Maintenance therapy can also affect patient outcomes.

Disclosures:
No relevant conflicts of interest to declare.
Upregulation of the Chemokine Receptor CCR5 on CD16+ Myeloid Blood Dendritic Cells in Allogeneic Hemopoietic Cell Transplant Patients Predicts for Acute Graft Versus Host Disease
Authors: Shahin Kifah , Sartor Mary M , Hart Derek NJ , Bradstock Kenneth F 
Published: October 2019

Abstract
Abstract 1982

Introduction:
Dendritic cells (DC) are centrally involved in the development of acute graft-versus-host disease (GvHD) following allogeneic hemopoietic cell transplantation (alloHCT). We previously showed that the activation status, as assessed by CMRF-44 antigen expression, of CD11c+ myeloid blood DC is highly associated with the onset and severity of acute GvHD (Transplantation. 2007;83:839–846). We also reported a positive correlation between acute GvHD and the expression of the chemokine receptor CCR5 on CD11c+ myeloid DC (Blood. 2009;114 Suppl.:2251). Given the phenotypic and functional heterogeneity of the CD11c+ DC population, we investigated CCR5 expression on the CD11c+ DC subsets and then monitored the informative CD11c+ CD16+ DC subset expression of CCR5 in the peripheral blood of 42 patients post alloHCT, and correlated the findings with GvHD.

Methods:
Peripheral blood was collected twice weekly up to Day 100 post transplant from 42 alloHCT patients. The expression of CCR5 receptor on CD11c+ and CD11c- DC subsets was evaluated using multiparameter flow cytometry.

Results:
Only the CD11c+ CD16+ DC subset lacked CCR5 and induced it upon alloactivation. Seventeen of 42 patients developed acute GvHD (5 grade I, 12 grades II-IV). The percentage of CD11c+ CD16+ DC expressing CCR5 correlated with the development of acute GvHD grades II-IV. The maximum CCR5 expression detected on CD11c+ CD16+ DC in patients prior to developing grades II-IV GvHD (mean 22.7 ± 4.3%, n=12) was higher than in those with grades 0-I GvHD (11.4 ± 1.7%, n=30) (p=0.0285). CCR5 levels >20% on CD16+ myeloid DC predicted grades II-IV GvHD with a sensitivity of 66.7% and specificity of 86.7%. Levels of expression of CCR5 on the CD11c+ CD16- DC and CD123+ plasmacytoid DC were not predictive of GvHD.

Conclusion:
Expression of CCR5 on circulating CD11c+ CD16+ myeloid DC post alloHCT correlated with the development of moderate to severe GvHD. This observation may reflect DC activation or altered DC homing during the alloimmune response. Detection of increased CCR5+ CD11c+ CD16+ DC may allow pre-emptive therapeutic intervention prior to the clinical diagnosis of GvHD.

Disclosures:
No relevant conflicts of interest to declare.
Second Stem Cell Transplantation (SCT) for Relapsed Leukemia Provides Only Modest Prolongation of Survival
Authors: McIver Zachariah A. , Hughes Thomas , Ito Sawa , Battiwalla Minoo , Koklanaris Eleftheria K. , Haggerty Janice , Hensel Nancy F. , Barrett A. John 
Published: October 2019

Abstract
Abstract 2001
Patients with leukemia relapsing after SCT have a dismal prognosis. Treatments ranging in intensity from palliation to second SCT are offered to such patients but the overall survival remains in the region of 3–4 months. Second SCT is typically restricted to selected patients deemed more likely to survive and experience further leukemia control. However, since a second SCT is associated with an increase risk of transplant related morbidity and mortality, it is important to determine whether this option has a survival benefit. We studied 60 consecutive relapsed patients who had received a myeloablative matched-sibling T-cell depleted SCT for a variety of hematological malignancies including AML, ALL, CML blastic phase, and MDS. Median patient age at time of first SCT was 36 years (range, 10 – 68), median T cell dose varied between 1–5 x104/kg. Thirty-five patients relapsed early (< 6 months post SCT) with a median survival after relapse of 170 days (range 45 – 402), and 25 patients relapsed late (> 6 months post SCT) with a median survival after relapse of 1005 days (range, 240 – 4459). Salvage therapies included tyrosine kinase inhibitors (for CML), intrathecal chemotherapy (for CNS leukemia), and systemic chemotherapy combinations predominantly involving fludarabine and cytarabine. Twenty-four patients (13 early relapse, and 11 >6 months), with a good performance score and showing some preliminary response to non-transplant therapy, received a 2nd SCT from their original donor. Our rationale for selecting these patients for a T replete 2nd SCT was based on the potential enhancement of graft-versus leukemia effects following the failed T-cell depleted SCT. Sixteen received myeloablative conditioning with either Busulphan or Melphalan, and 8 patients received a nonmyeloablative regimen specific to their disease. Of the 36 patients not transplanted, 14 received a donor lymphocyte infusion, and 22 received palliative chemotherapy or hospice care only. Compared with non-transplant treatment patients, only those relapsing early after their first SCT experienced a significant but small survival benefit from 2nd SCT, with most patients dying from relapsed disease (median 55 vs 154 days, untransplanted vs transplanted; HR = 0.4, p = 0.01). In untransplanted patients survival was not different between any treatment option. Although patients selected for 2nd SCT represented a more favorable group, it was disappointing that intensive treatment only resulted in a 3 month prolongation of median survival. These results do not indicate an important benefit for second transplant in any patient relapsing with leukemia after SCT.

Disclosures:
No relevant conflicts of interest to declare.
The bHLH Transcription Factors SCL and LYL1 Awaken Hematopoietic Stem Cells by Repression of p21
Authors: Curtis David J. , Nguyen Nhu-Y , Salmon Jessica 
Published: October 2019

Abstract
Abstract 214
The basic helix-loop-helix (bHLH) transcription factors SCL (TAL1) and LYL1 are regulators of adult hematopoietic stem cell (HSC) activity with significant functional redundancy: HSCs lacking SCL (SCLδ/δ) have a mild defect in short-term repopulating activity whilst HSCs lacking LYL1 (LYL1−/−) have normal repopulating activity. In contrast, we have shown previously that HSCs lacking both SCL and LYL1 (DKO) are unable to grow in vitro and have no in vivo repopulating activity. Phenotypic and expression analyses of SCLδ/δ, LYL1−/− and DKO mice were performed to determine how bHLH factors regulate HSC activity. Consistent with the short-term repopulating defects of SCLδ/δ HSC, Lineage negative Sca-1+ c-Kit+ (LSK) bone marrow cells from SCLδ/δ mice had reduced in vitro replating activity associated with increased quiescence – 90% in G0 compared with 70% in normal LSK. Increased quiescence was associated with delayed hematopoietic recovery following treatment of mice with 5-Fluorouracil. Consistent with the increased quiescence, expression of the cell cycle inhibitor, Cdkn1a (p21) was increased three-fold in SCLδ/δ and LYL1−/− LSK. Moreover, p21 levels in LSK isolated from DKO mice were increased 50-fold. To determine the functional relevance of the elevated levels of p21 in DKO HSCs, we generated DKO mice on a p21-deficient (p21−/−) background. Remarkably, loss of p21 rescued in vitro cell growth of DKO progenitors. More importantly, primary and secondary competitive repopulation assays demonstrated multi-lineage repopulating activity of p21−/− DKO HSCs. These results suggest the bHLH factors SCL and LYL1 function as repressors of p21, allowing HSCs to enter cell cycle during stress hematopoiesis.

Disclosures:
No relevant conflicts of interest to declare.
Potential Benefits of Extended Genotype Matching to Chronically Transfused Patients with Sickle Cell Disease
Authors: Helman Ricardo , Cancado Rodolfo , Mota Mariza A , Dezan Marcia R , Kutner Jose Mauro , Chiattone Carlos S , Castilho Lilian 
Published: October 2019

Abstract
Abstract 2144

Background:
Management of RBC alloimmunization in Sickle Cell Disease (SCD) patients has been the subject of much debate, and currently there is no standard approach. Many programs transfuse SCD patients with RBCs that are phenotype-matched for D, C, c, E, e and K. Although these approaches reduce the incidence of alloantibody production, patients still become alloimmunized. Based on this we aimed to identify the rates of alloimmunization in chronically transfused SCD patients and compare the phenotyping with genotyping methods to find a better way to match RBC units to those patients. Methods: We selected 45 SCD patients (homozygous for hemoglobin S) with multiple transfusions, previously phenotyped for ABO, Rh (D, C, c, E, e) and K1. Phenotypes were determined by hemagglutination using gel cards (Diamed® ). Genotypes were determined by a DNA array using the Human Erythrocyte Antigen BeadChip (“HEA”) from Bioarray Solutions. All SCD patients included in this study were in chronical transfusion program; receiving multiple transfusions. The median age was 24y; there were 28(62%) females and 17(37.8%) males. The median of transfusions were 53 (5–78) and 40 (88.9%) patients received more than 20 phenotype-matched units for Rh (D, C, c, E, e) and K1. Results: Of the 45 SCD patients selected, 11 (24.4%) had alloantibodies. The antibody specificities found in these patients were anti-D, -C, -CW, -E, -Jka, -Jkb, -Fya, -Dia, -s. Although the patients were receiving Rh and K phenotype-matched units 8 (17%) of them became alloimmunized to Rh antigens and on those patients we found discrepancies between the previous phenotype and genotype-derived phenotype. Our results showed that the risk of immunization increases in patients over 40 years old (p= 0.05) and with the number of transfusion events. Patients with more than 20 RBC transfusions have a tendency for alloimmunization (p=0.65). We also observed that genotyping was more effective than hemagglutination in determining patient's correct phenotype. Conclusion: Our data show that even with the implementation of Rh and K phenotype-matching in chronically transfused patients with SCD, they still become alloimmunized to other antigens with high immunization risk and also to Rh antigens due to the limitations of the hemagglutination. The relevance of genotype determination of blood groups for the management of multiple transfused patients with SCD has been demonstrated by allowing the determination of the true blood group genotype, by assisting in the identification of suspected alloantibodies and in the selection of antigen-negative. As donor genotyping for the most clinically relevant blood group antigens by automated DNA techniques are becoming available, extended genotype matching should be considered in this group of patients.

Disclosures:
No relevant conflicts of interest to declare.
Delayed Embryonic to Adult Globin Switching in HMGB2 Knock Out Mice
Authors: Marini Giuseppina M. , Asunis Isadora , Cabriolu Annalisa , Porcu Loredana , Sau Anna Maria , Manchinu Francesca , Porcu Susanna , Marongiu Franca M. , Poddie Daniela , Ronfani Lorenza , Bianchi Marco , Ronchi Anotonella , Ristaldi Maria Serafina , Cao Antonio , Moi Paolo 
Published: October 2019

Abstract
Abstract 2152
Hypersensitive site 2 (HS2) of the locus control region (LCR) is required for the optimal regulation of the beta globin gene cluster. Screening a λgt11 cord blood cDNA library with the tandem NFE2 repeat of HS2 as recognition site probe, we isolated 14 cDNA clones of HMGB2, a chromatin non histone protein. Binding to the HS2 region was confirmed in vivo by ChIP assay. Transactivation analysis in K562 cells showed mild repression of a luciferase reporter driven by HS2 and the γ-promoter. The DNA bending capacity and the increased expression of HMGB2 during erythroid differentiation are properties well suited to facilitate LCR looping toward the β-globin genes, the mechanism thought to mediate globin gene activation. Hence, HMGB2 binding to HS2 may be relevant for the regulation of the β-globin gene cluster. To assess the function of HMGB2 as a possible regulator of the globin genes we analyzed the hematological phenotype of the HMGB2 knock out mice during erythroid differentiation. In peripheral blood from E18 fetus or adult mice no hematological differences were found among normal, heterozygous or homozygous HMGB2 mice. However, at earlier stages of development, at E12, β-minor and major were slightly reduced in HMGB2−/− mice, whereas embryonic εy and βH1 globin genes were overexpressed 4–5 times compared to normal littermate mice. These results support a repressing activity of HMGB2 on embryonic globin genes and a possible role in the switching of hemoglobins during early stages of differentiation. The lack of any hematological phenotype in the latter stages of development may be explained by a temporal restriction in the expression of HMGB2 or by the vicarious activity of other HMGB proteins during definitive erythropoiesis

Disclosures:
No relevant conflicts of interest to declare.