bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A14: Cellular immunotherapy for refractory hematological malignancies: Haploidentical donor lymphocyte infusions generate an allogeneic effect that targets leukemia.
Authors: Reagan John L. , Fast Loren D. , Nevola Martha , Schumacher Andrew , Rosati Kayla , Safran Howard , Quesenberry Matt I. , Winer Eric P. , Butera James N. , Quesenberry Peter J.
Published: August 2015

Background/Objective: Allogeneic stem cell transplantation (allo-SCT) is an effective treatment modality for leukemia and lymphoma that exerts much of its therapeutic benefit via a graft versus tumor response. Its applicability is limited by toxicity from preconditioning chemoradiation and graft versus host disease. We present data from a Phase II IRB and FDA approved clinical trial in which haploidentical allogeneic cells are infused into patients with refractory hematologic malignancies without prior chemotherapy or radiation. The goal is to generate a robust allogeneic response created via donor cell rejection that breaks host tumor tolerance without the toxicity profile seen in allo-SCT.

Methods: Eligible patients have refractory acute leukemias and aggressive systemic lymphomas without curative options. HLA haploidentical donors are identified then undergo leukapheresis without stem cell mobilization. 1-2x108 CD3+ cells/kg are infused unprocessed immediately following collection. Peripheral blood samples collected 1, 24, 48, 72 and 168 hours after infusion are examined for effector cell populations, stimulatory/inhibitory signals, and cytokine release profiles.

Results: Three patients have been infused haploidentical cells. Two developed hyperpyrexia following treatment that persisted for 48 hours. One of three patients demonstrated a decrease in peripheral blood and bone marrow blast counts following therapy (Reduction in peripheral absolute blast count from 3900/uL to 1200/uL and bone marrow blasts from 43% to 21% four weeks post therapy). No Grade 3 or 4 toxicities or durable chimerism was seen. Host T cells demonstrated cytolytic effector molecule expression but little cytolytic activity, possibly secondary to rapid up-regulation of PD-1 and PD-1 ligands by host CD8+ cells and leukemia cells, respectively.

Discussion: Haploidentical donor cellular infusions are well tolerated and demonstrate biological activity in relapsed leukemia. Lab correlative studies suggest potential future mechanisms to augment response involving PD-1 blockade. Our method provides a true bench to bedside approach utilizing adoptive immunotherapy created via a host allogeneic rejection response.

Citation Format: John L. Reagan, Loren D. Fast, Martha Nevola, Andrew Schumacher, Kayla Rosati, Howard Safran, Matt I. Quesenberry, Eric P. Winer, James N. Butera, Peter J. Quesenberry. Cellular immunotherapy for refractory hematological malignancies: Haploidentical donor lymphocyte infusions generate an allogeneic effect that targets leukemia. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A14.
Abstract A15: In vivo efficacy of a CD38-specific engineered toxin body.
Authors: Robinson Garrett L. , Rajagopalan Sangeetha , Brieschke Brigitte , Erdman Jennifer , Neill Jane , Flores Rodney , Foree Julia , Null William , Liu Jensing , Higgins Jack P. , Willert Erin K.
Published: August 2015

The cell surface glycoprotein CD38 is highly expressed on the surface of several B cell lineage cancers, such as the plasma cell malignancy multiple myeloma, some lymphomas and chronic lymphocytic leukemia (CLL), where it is a marker of unfavorable prognosis. CD38 is a transmembrane receptor and ectoenzyme that is absent or expressed at a low level on most resting leukocytes under normal conditions, making this an appealing target for directed therapy for hematological malignancies. Recent clinical trials with antibodies to CD38 have shown promise in multiple myeloma. While these antibodies rely on the recruitment of an immune response for cytotoxicity, we have developed an engineered toxin body (ETB) comprising a CD38 binding scFv and a modified Shiga-like Toxin A subunit capable of specifically recognizing and directly killing CD38 expressing cells. The CD38 targeted ETB has a different mechanism of action than current treatments for multiple myeloma (such as immunomodulatory agents, protease inhibitors and chemotherapies). Our CD38 targeted ETB has shown to be well tolerated in mice and displays dose dependent efficacy in a CD38 positive tumor setting. The CD38 targeted ETB significantly reduced tumor burden and increased survival over a 40-fold dose range in a disseminated Daudi xenograft, early treatment model. In this setting, the mean tumor burden at day 28 was reduced to 29% of control for the lowest dose group (0.05 mg/kg) and less than 1% of control for the two higher doses (0.5 and 2 mg/kg). Median survival of the control, untreated group was 34 days; the low dose group had extended median survival to 59.5 days and, at the day 60 study end, 90 or 100% of mice were alive in the higher two dosing groups. Our results show that the CD38 targeted ETB is a promising targeted therapeutic agent against CD38 positive cancer cells and is currently under further development.

Citation Format: Garrett L. Robinson, Sangeetha Rajagopalan, Brigitte Brieschke, Jennifer Erdman, Jane Neill, Rodney Flores, Julia Foree, William Null, Jensing Liu, Jack P. Higgins, Erin K. Willert. In vivo efficacy of a CD38-specific engineered toxin body. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A15.
Abstract A27: Risk of hematopoietic cancer associated mortality among workers in the poultry slaughtering and processing industries.
Authors: Bangara Saritha , Felini Martha J. , Aryal Subhash , Sterling David , Johnson Eric S.
Published: August 2015

Objectives: Previous occupational cohort studies among poultry workers have revealed an excess risk of cancer-related mortality, including deaths due to hematopoietic malignancies. However, specific occupational and non-occupational exposures contributing to this excess risk have yet to be identified. Poultry workers are particularly at high risk since an average of 175,000 chickens are killed daily in poultry plants in the United States. This brings poultry workers into intimate contact with their blood, organs, and secretions, which may harbor transmissible oncogenic viruses. Moreover, they are exposed to potentially carcinogenic chemicals that are emitted during packaging and preparation. Hence, our study was conducted to provide preliminary evidence of which specific poultry related and non-poultry related occupational tasks increase the risk of mortality from hematopoietic cancer among poultry workers.

Methods: A pilot case-cohort study was conducted using a combined cohort of 30,411 highly exposed poultry workers and 16,408 control subjects. Exposures pertaining to poultry and non-poultry related tasks were self-reported through telephone interviews from controls and next-of-kin for cases. Hematopoietic cancer mortality risk was assessed using logistic regression odds ratios (OR) and proportional hazard ratios (HR).

Results: One hundred fifty-two cases of hematopoietic cancer occurred in this cohort between January 1, 1990 and December 31, 2003. Since this is a feasibility study, exhaustive attempts were not made to identify study subjects and their next of kin. Thus, we report here on the first 52 (69%) of the 75 cases whose next-of-kin were traced. Similarly, of the first 214 controls that were traced, 152 (71%) completed interviews. Preliminary analysis is currently underway to identify the specific task exposures contributing to this excess risk.

Conclusion: We expect the results of our study will confirm known risk factors related to hematopoietic cancers, and uncover new risk exposures that have yet to be appreciated in the general population due to their low level exposures. Using high-risk unique populations offers an opportunity to better understand molecular mechanisms that investigators may explore to aid in future drug development.

Citation Format: Saritha Bangara, Martha J. Felini, Subhash Aryal, David Sterling, Eric S. Johnson. Risk of hematopoietic cancer associated mortality among workers in the poultry slaughtering and processing industries. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A27.
Abstract A39: Initial characterization of genetically engineered mice carrying a conditional allele of a splicing factor gene (U2AF1) commonly mutated in myeloid disorders.
Authors: Varmus Harold
Published: August 2015

Putative “driver” mutations in genes encoding splicing factors---including recurrent mutations in U2AF1, which encodes a component of the U2 auxiliary factor to regulate pre-mRNA splicing---have been identified in myeloid dysplasias, related neoplasms, and lung adenocarcinomas. To study the functional impact of U2AF1 mutations, we have created transgenic mice carrying a conditional mutant allele, MG-S34F, at the endogenous U2AF1 locus. We have crossed the MG-S34F mice with mice carrying a Mx1-Cre transgene, and demonstrated efficient Cre-mediated recombination and expression of U2AF1-S34F in bone marrow cells two weeks after treatment with poly IC. Bone marrow cells from compound transgenic mice had a modest but statistically significant reduction in their ability to form monocyte and granulocyte colonies in culture. A small cohort of mice is also being followed for long-term hematologic defects after exposing these mice to low doses of N-ethyl-N-nitrosourea (ENU). While U2AF1-S34F expression coupled with ENU treatment has not produced myeloid leukemia after 3 months, a low ratio of U2AF1-S34F to wild-type U2AF1 RNA in blood cells implies that expression of U2AF1-S34F affects normal hematopoiesis or survival of blood cells in mice. We are now expanding our mouse cohort to study the hematologic defects apparently induced by U2AF1-S34F in greater detail.

Citation Format: Dennis Liang Fei, Harold Varmus. Initial characterization of genetically engineered mice carrying a conditional allele of a splicing factor gene (U2AF1) commonly mutated in myeloid disorders. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A39.
Abstract A40: Megakaryocyte endomitosis requires Pak2 to regulate actin and microtubule networks.
Authors: Kosoff Rachelle E. , Chernoff Jonathan
Published: August 2015

Megakaryocytes mature and differentiate into polyploid cells in the bone marrow, and migrate from the osteoblastic niche to the vascular niche by means of an SDF-1α gradient, culminating in the release of platelets into circulation. Failure to do so results in myeloproliferative disorders, which can manifest as thrombocytopenia. Many chemotherapeutic agents are known to induce thrombocytopenia and other platelet disorders. Regulation of megakaryocyte differentiation and polyploidization is controlled by MAPK associated proteins, and cytoskeleton regulating proteins. p21-activated kinase 2 (Pak2) is known to regulate these two pathways, but nothing is currently known about the role of Pak2 in megakaryocyte biology. In our study, we sought to demonstrate that Pak2 is essential for proper megakaryocyte differentiation, maturation and polyploidization, in vivo and in vitro. Inducible deletion of Pak2fl/fl results in 100% lethality within 20 days of cre induction, specifically in hematopoietic tissues (Mx1-cre). Peripheral blood analysis demonstrates thrombocytopenia (reduced platelet counts), along with increased neutrophil count (neutrophilia) and decreased lymphocyte count. Bone marrow histology and analysis by flow cytometry demonstrates altered megakaryocyte differentiation, observed by elevated megakaryocyte(Mk) precursors in the bone marrow (Lin-ckit+Sca1- CD150+CD41+), elevated mature bone marrow Mks (CD41+), increased number of polyploid cells(>8N) and hyperplastic megakaryocytes. In vitro culture of bone marrow derived Pak2-null megakaryocytes demonstrates elevated polyploidization, altered β1-tubulin structure and reduced platelet formation. Additionally, cre activation in platelets and megakaryocytes using a PF4-cre driver (platelet factor 4) recapitulates the enhanced polyploidization phenotype observed in the Mx1-cre model. Ultimately, we demonstrate that Pak2 signals through LIMK, cofilin, and myosin light chain 2 (MLC2) to regulate megakaryocyte cytoskeleton during differentiation and polyploidization.

In summary, Pak2 is an important regulator of megakaryocyte maturation and platelet formation in vivo via regulation of proteins involved in cytoskeletal dynamics.

Citation Format: Rachelle E. Kosoff, Jonathan Chernoff. Megakaryocyte endomitosis requires Pak2 to regulate actin and microtubule networks. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A40.
Abstract B09: Exploiting oncogene-induced DNA replicative stress as synthetic lethal approach to target myeloma.
Authors: Cottini Francesca , Hideshima Teru , Richardson Paul , Anderson Kenneth , Tonon Giovanni
Published: August 2015

This abstract is being presented as a short talk. A full abstract is printed in the Proffered Abstracts section (PR04) of the Conference Proceedings.

Citation Format: Francesca Cottini, Teru Hideshima, Paul Richardson, Kenneth Anderson, Giovanni Tonon. Exploiting oncogene-induced DNA replicative stress as synthetic lethal approach to target myeloma. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr B09.
Abstract B26: Role of ribosomal protein, Rpl22 in regulating leukemic transformation.
Authors: Patel Nehal Solanki , Greenberg Noa , Peri Suraj , Rao Shuyun , Rhodes Michele , Wiest David
Published: August 2015

Inactivation of ribosomal proteins (RP) is known to cause diseases called ribosomopathies, which are often associated with abnormal hematopoiesis and an increased risk for development of leukemia. Our laboratory has recently reported an important link between inactivation of one such ribosomal protein, Rpl22, and poor survival in T cell acute lymphoblastic leukemia (T-ALL) patients. Preliminary bioinformatic analysis shows that RPL22 is lost in ~10% of pediatric T-ALL patients, who exhibit a more aggressive disease course. Deletion of the RPL22 locus is also enriched in the early T-cell precursor (ETP-ALL) subset of T-ALL patients, which exhibit a more aggressive disease course. Thus, RPL22 loss appears to be a marker for poor outcome in pediatric T-ALL patients. While RP inactivation has previously been linked to increased cancer risk, the mechanistic basis for this linkage remained unclear. We have recently demonstrated that inactivation of Rpl22 promotes leukemic transformation by activating NF-kB and inducing the stem cell gene, LIN28B. Nevertheless, the molecular link between Rpl22 inactivation and the induction of NF-kB activity remained unclear. We have now determined that inactivation of Rpl22 activates NF-kB signaling by exacerbating ER stress responses. Indeed, Rpl22 loss results in hyperactivation of the PERK-EIF2α-ATF4 stress pathway, which is known to activate NF-kB. We have demonstrated that knockdown of PERK using shRNA abrogates the activation of NF-kB in Rpl22 mutant cells and returns Lin28B expression levels to baseline. This reduction in Lin28B eliminates the predisposition to transformation exhibited by Rpl22 mutant cells, as evidenced by decreased formation of colonies in soft agar. Taken together, these data suggest that RPL22 inactivation may serve as a negative prognostic indicator in T-ALL and that pharmacologic targeting of ER stress pathways may represent a novel therapeutic alternative in this molecularly-defined subclass of T-ALL.

Citation Format: Nehal Solanki Patel, Noa Greenberg, Suraj Peri, Shuyun Rao, Michele Rhodes, David Wiest. Role of ribosomal protein, Rpl22 in regulating leukemic transformation. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr B26.
Abstract B46: VLA-4 targeted nanoparticles carrying a novel anti-Myc prodrug prolongs survival in a mouse model of multiple myeloma.
Authors: Gupta Deepti Sood , Pan Dipanjan , Hu Grace , Senpan Anagana , Yang Xiaoxiao , Prochownik Edward V. , Lanza Gregory M. , Tomasson Michael H.
Published: August 2015

The MYC oncoprotein drives multiple myeloma (MM) pathogenesis, but the utility of small molecule inhibitors of MYC-MAX dimerization is limited by poor efficacy. We determined the efficacy of lipase labile MYC-MAX inhibitor prodrug (MI1-PD) loaded nanoparticles targeted via integrin {alpha 4 beta1 α4β1) or Very Late Antigen-1 (VLA-4)} in myeloma mice. We hypothesized that NPs containing specific targeting to myeloma cells, would enhance the therapeutic efficacy of MI1-PD containing NPs. The antiproliferative activity of intergin VLA-4-Targeted MI-1PD NPs (iTM-NPs) was determined in mouse cell line (5TGM1) in vitro and its effect on the survival in C57Bl/KaLwRij-5TGM1 murine model of myeloma in vivo. iTM-NPs (approximately 20 nm in diameter, 5% w/w MI1-PD loading) under in vitro conditions exhibited inhibition of cell growth compared to the controls. Also, C57Bl/KaLwRij-5TGM1 mice that received intravenous injection of iTM-NPs demonstrated greater survival rate over the controls. These results demonstrate the feasibility of using VLA-4 targeted nanotherapy approach to improve the availability of anti-Myc small molecule inhibitors for multiple myeloma and other cancers.

Citation Format: Deepti Sood Gupta, Dipanjan Pan, Grace Hu, Anagana Senpan, Xiaoxiao Yang, Edward V. Prochownik, Gregory M. Lanza, Michael H. Tomasson. VLA-4 targeted nanoparticles carrying a novel anti-Myc prodrug prolongs survival in a mouse model of multiple myeloma. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr B46.
Abstract IA08: The microenvironment in CLL: Cellular and molecular players and emerging therapeutic targets.
Authors: Burger Jan A.
Published: August 2015

The tissue microenvironment plays an important role of in the pathogenesis of chronic lymphocytic leukemia (CLL), delivering signals that promote the clonal expansion of the malignant B cells, as well as drug resistance. The complex cross talk between neoplastic B cells and the microenvironment, for example in secondary lymphoid organs, has been increasingly well characterized, and several cellular and molecular key players have emerged. Important cells in the CLL microenvironment are monocyte-derived nurselike cells (NLC), mesenchymal stromal cells (MSC), and T cells, which engage in a dialogue with the neoplastic CLL cells, often via specific receptor-ligand pairs. Engagement of CLL surface receptors by ligands in the tissue microenvironment, for example activation of B cell receptor (BCR) signaling, triggering of TNF family members (i.e. BAFF, APRIL), and activation of chemokine receptors and adhesion molecules result in the activation of signaling cascades that support the maintenance and expansion of the CLL clone. BCR signaling plays a particularly important pathogenic role in CLL, based on structural restrictions of the BCR, and signs of BCR-dependent survival and growth of the malignant B cells. Ligand-independent (“autonomous”) and ligand-dependent BCR signaling have been characterized, the latter triggered by (auto-) antigens present in the tissue microenvironment. Based on high response rates and durable remissions in early-stage clinical trials, there is rapid clinical development of inhibitors targeting BCR-associated kinases (BTK, PI3Kδ), which currently are changing treatment paradigms in CLL. Clinical and translational aspects of these new targeted therapeutics will be discussed, along with an outlook into future therapeutic strategies.

Citation Format: Jan A. Burger. The microenvironment in CLL: Cellular and molecular players and emerging therapeutic targets. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA08.
Abstract IA19: The evolutionary landscape of chronic lymphocytic leukemia.
Authors: Wu Catherine J.
Published: August 2015

Clonal evolution is a key feature of cancer progression and relapse. Recent studies across cancers have demonstrated the extensive degree of intratumoral heterogeneity present within individual cancers. We hypothesized that evolutionary dynamics contribute to the variations in disease tempo and response to therapy that are highly characteristic of chronic lymphocytic leukemia (CLL). We have recently investigated this phenomenon by developing a pipeline that estimates the fraction of cancer cells harboring each somatic mutation within a tumor through integration of whole-exome sequence (WES) and local copy number data (Landau et al., Cell 2013). By applying this analysis approach to 149 CLL cases, we discovered earlier and later cancer drivers, uncovered patterns of clonal evolution in CLL and linked the presence of subclones harboring driver mutations with adverse clinical outcome. Thus, our study, generated from a heterogeneous sample cohort, strongly supports the concept that CLL clonal evolution arises from mass extinction and therapeutic bottlenecks which lead to the emergence of highly fit (and treatment resistant) subclones.

We further hypothesize that epigenetic heterogeneity also shapes CLL clonal evolution through interrelation with genetic heterogeneity. Indeed, in recent work, we have uncovered stochastic methylation disorder as the primary cause of methylation changes in CLL and cancer in general, and that this phenomena impacts gene transcription, genetic evolution and clinical outcome. Ongoing studies focus on establishing a framework for understanding the stepwise transformation of B cells, and elucidating the role of the dynamic evolutionary landscape of CLL on its diagnosis, prognosis and treatment.

Citation Format: Catherine J. Wu. The evolutionary landscape of chronic lymphocytic leukemia. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA19.
Abstract IA21: AML genomics: An update.
Authors: Mardis Elaine R.
Published: August 2015

Our fundamental understanding of the genomic landscape of acute myeloid leukemia (AML) has significantly improved due to large-scale genomic characterization of AML genomes, transcriptomes and methylomes. Retrospective analyses of primary and relapse disease genomes has also illustrated the changes in heterogeneity that occur during progression, and studies of mouse xenografts of AML have illustrated the biological competition among subclones to seed progressive disease. I will discuss next steps in our clinical sequencing of AML, aimed at beginning to apply our fundamental knowledge about the disease to the cancer care setting. Various technical challenges will be highlighted as well as discussing the overall framework for beginning to understand the data we will generate.

Citation Format: Elaine R. Mardis. AML genomics: An update. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA21.
Abstract IA24: Regulation of acute leukemia initiation and progression by long noncoding RNAs.
Authors: Aifantis Iannis
Published: August 2015

Recent efforts to functionally annotate the human genome have revealed that up to 70% of our DNA is transcriptionally active. Since a very small portion of our genome encodes proteins many have hypothesized that a portion of this pervasive transcription results in production of non-coding RNA. By generating high depth RNA-Seq datasets integrated with chromatin features, several labs have revealed the presence of many thousands of previously un-annotated long non-coding RNAs (lncRNA), which are dynamically expressed in response to various stimuli in diverse cellular contexts. Despite these compelling advances, the vast majority of putative lncRNAs have not been proven to be functionally important, although a small portion have clearly been shown to play key regulatory roles. Most importantly, very little is known on the biological role of lncRNAs for human disease and specifically cancer. We provide here, using a combination of deep transcriptome sequencing, high-resolution transcription factor occupancy mapping and chromosome conformation capture data, the first comprehensive identification and characterization of lncRNA expression and function in T-cell acute lymphoblastic leukemia, an aggressive hematologic malignancy affecting both children and adults, driven by oncogenic NOTCH1 mutations and transcriptional activation. Moreover, we provide the first map of oncogene (NOTCH1)-targeted lncRNAs in this disease and identify an individual lncRNA (called LUNAR1) that appears to be essential for tumor growth as it controls cytokine (IGF1) signaling. Indeed, we were able to show that the LUNAR1 locus loops on a novel IGF1R enhancer controlling the expression of this important cytokine receptor. These studies suggest that: a) lncRNAs could be used as both biomarkers and therapy targets in human cancer, b) more efficient methods for large-scale inference and validation of lncRNA function are needed to fully understand their biological significance and, c) LUNAR1 is one of the first lncRNAs that can control growth of acute leukemia and a potential therapeutic target. These points will be addressed in this presentation.

Citation Format: Iannis Aifantis. Regulation of acute leukemia initiation and progression by long noncoding RNAs. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA24.
Abstract IA33: Regulation of self-renewal in cancer stem cells.
Authors: Falzacappa Maria Vittoria Verga , Insinga Alessandra , Pelicci Pier Giuseppe
Published: August 2015

We showed that extended self-renewal of leukemia stem-cells (LSCs) is the consequence of the constitutive activation of the cell-cycle inhibitor p21. The pool of LSCs is markedly reduced in p21-/- APLs, and the residual LSCs hyperproliferate and accumulate massive DNA-damage (DD). Notably, p21 is indispensable to maintain the pool of LSCs in PML-RAR leukaemias (PML-RAR – p21-/- leukaemias are not transplantable in syngenic mice). It is not known whether p21 extends the self-renewal of LSCs by activating DD repair, restricting the cell-cycle or regulating their survival. Preliminary results from our lab showed that p21-/- APLs re-acquire the ability to initiate leukemogenesis when transplanted into immunodeficient mice (RAG) or syngeneic mice after γ-irradiation. In these conditions, the growing leukemias are indistinguishable from primary WT APLs and can be re-transplanted into immunodeficient, but not syngeneic mice, suggesting that expansion of p21-/- LSCs is controlled by the host immune-system. Further experiments suggested that p21-/- LSCs are cleared by T-cells since p21-/- APLs: i) initiate leukemias when transplanted into RAG1-/- mice (which lack B, T and NKT cells), but not in JHT mice (lacking only B-cells), and ii) do not grow in NOD/SCID mice when the recipients are injected with a T cell population primed with p21-/- blasts (e.g. obtained from the spleen of WT mice injected with p21-/- APLs), but not with non-primed T cells or T cells primed with WT blasts. T-cells primed with p21-/- blasts are also able to suppress the in vivo growth of wt APLs, but not of T-ALLs. We hypothesize that the immune-surveillance contributes to the elimination of DNA-damaged SCs, and that DNA-damaged LSCs have developed evasion strategies based on p21 activation.

Citation Format: Maria Vittoria Verga Falzacappa, Alessandra Insinga, Pier Giuseppe Pelicci. Regulation of self-renewal in cancer stem cells. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA33.
Abstract IA39: The genetic basis of diffuse large B cell lymphoma.
Authors: Pasqualucci Laura
Published: August 2015

Diffuse large B cell lymphoma (DLBCL), the most common form of human lymphoma, is a heterogeneous neoplasm comprising multiple genetic, phenotypic and clinical subtypes, approximately 50% of which are incurable. These tumors may arise de novo or from the transformation of more indolent lymphomas, as observed in 30-40% of follicular lymphoma (FL) cases. Over the past decade, the introduction of next-generation sequencing technologies combined with genome-wide copy number analysis has allowed to comprehensively define the genomic landscape of this disease, leading to the identification of multiple genes and signaling pathways that are dysregulated by genetic lesions and represent potential targets for diagnosis and therapy. In addition to perturbations in the transcriptional control of apoptosis, differentiation and DNA damage responses or NF-κB activation, these efforts revealed the frequent targeting of genes implicated in chromatin remodeling and immune recognition/surveillance.

In particular, one of the most commonly disrupted programs in both de novo DLBCL, FL and transformed FL (tFL) comprises genes encoding histone/chromatin modifying enzymes, including methyltransferases (MLL2, EZH2) and acetyltransferases (CREBBP, EP300), which may play a central role during malignant transformation. Interestingly, sequential analysis of tumor samples during transformation of FL to tFL indicates that inactivating mutations of CREBBP and MLL2 are acquired early in the evolutionary history of a common mutated ancestral clone. The disruption of these genes by genetic alterations may thus contribute to malignant transformation by shaping the epigenetic landscape of the cancer cell as well as by perturbing specific biological programs, in part through the altered balance between acetylation-mediated activation of the p53 tumor suppressor and inactivation of the BCL6 proto-oncogene. This talk will cover recent advances in understanding the genetic basis of DLBCL, as revealed by in vitro and in vivo studies.

Citation Format: Laura Pasqualucci. The genetic basis of diffuse large B cell lymphoma. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA39.
Abstract IA47: Epigenetic programming and therapy in germinal center derived B-cell lymphomas.
Authors: Melnick Ari M.
Published: August 2015

Diffuse Large B-cell Lymphomas (DLBCLs) are a heterogeneous group of diseases initiating from germinal center (GC) B cells. GC B cells are uniquely specialized to tolerate rapid proliferation, and physiological genomic instability in order to generate a diverse set of clones of cells encoding high affinity antibodies. This accelerated micro-evolutionary process requires the concerted action of transcription and epigenetic factors that collectively reprogram B cells to overcome many of their normal checkpoint restraints and tolerate the various stresses associated with affinity maturation. The GC phenotype poses a significant risk of malignant transformation to B cells, which must accordingly balance suppression of checkpoints with suppression of pro-oncogenic genes. Epigenetic regulatory complexes play a critical role in lymphomagenesis. EZH2, which epigenetically silences genes through histone 3 lysine 27 methylation is upregulated in normal and malignant GC B cells. EZH2 is often affected by gain of function mutations in lymphomas that alter its enzymatic specificity. EZH2 mediates GC formation by transiently suppressing checkpoint genes and terminal differentiation genes through formation of bivalent chromatin domains. EZH2 somatic mutations induce germinal center hyperplasia and malignant transformation, and cooperate with other oncogenes such as BCL2. EZH2 specific inhibitors can suppress the growth of GC derived lymphoma cells in vitro and in vivo, and are currently being evaluated in early phase clinical trials. DNA methyltransferase 1 (DNMT1) is required for B cells to form GCs, and GC B cells display cytosine methylation redistribution as compared to resting or naïve B cells. DLBCLs in turn exhibit prominent and heterogeneous disruption of cytosine methylation distribution, with specific and distinct DNA methylation profiles occurring in different lymphoma subtypes. Epigenetic heterogeneity is associated with unfavorable outcome in B-cell lymphomas, suggesting that epigenetic diversity may provide a survival advantage to lymphoma cell populations. DNA methyltransferase inhibitors can reprogram lymphoma cells to develop a form of incomplete senescence that sensitizes lymphoma cells to more readily respond to chemotherapy. DNA methyltransferase inhibitors can be safely combined with standard lymphoma therapies for the up-front treatment of patients with high-risk lymphomas.

Citation Format: Ari M. Melnick. Epigenetic programming and therapy in germinal center derived B-cell lymphomas. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr IA47.
Pristimerin Inhibits Prostate Cancer Bone Metastasis by Targeting PC-3 Stem Cell Characteristics and VEGF-Induced Vasculogenesis of BM-EPCs
Authors: Huang Shuai , He Peiheng , Peng Xinsheng , Li Jinglei , Xu Dongliang , Tang Yubo
Published: August 2015

Background/Aims: Prostate cancer (PCa) is one of the most common malignant cancers and a major leading cause of cancer deaths in men. Cancer stem-like cells are shown to be highly tumorigenic, pro-angiogenic and can significantly contribute to tumor new vessel formation and bone marrow derived-EPCs (BM-EPCs) are shown to recruit to the angiogenic switch in tumor growth and metastatic progression, suggesting the importance of targeting cancer stem cells (CSCs) and EPCs for novel tumor therapies. Pristimerin, an active component isolated from Celastraceae and Hippocrateaceae, has shown anti-tumor effects in some cell lines in previous studies. However, the effect and mechanism of Pristimerin on CSCs and EPCs in PCa bone metastasis are not well studied. Methods: The effect of Pristimerin on PC-3 stem cell characteristics and metastasis were detected by spheroid formation, CD133 and CD44 protein expression, matrix-gel invasive assay and colony-formation assay in vitro, VEGF and pro-inflammatory cytokines expression by ELISA assay, and tumor tumorigenicity by X-ray and MR in NOD-SCID mice model in vivo. In addition, we also detected the effect of Pristimerin on VEGF-induced vasculogenesis and protein expression of BM-EPCs. Results: Pristimerin could significantly inhibit spheroid formation and protein expression of CD133 and CD44, reduce VEGF and pro-inflammation cytokines expression of PC-3 cell, and prevent the xenografted PC-3 tumor growth in the bone of nude mice. The present data also showed that Pristimerin significantly inhibited VEGF-induced vasculogenesis of BM-EPCs by suppressing the EPCs functions including proliferation, adhesion, migration, tube formation and inactivation the phosphorylation of VEGFR-2, Akt and eNOS. Conclusion: These data provide evidence that Pristimerin has strong potential for development as a novel agent against prostate bone metastasis by suppressing PC-3 stem cell characteristics and VEGF-induced vasculogenesis of BM-EPCs.
The Innate Immune Receptor CD14 Mediates Lymphocyte Migration in EAE
Authors: Halmer Ramona , Davies Laura , Liu Yang , Fassbender Klaus , Walter Silke
Published: August 2015

Background: Multiple sclerosis is the most common autoimmune disease of the central nervous system in young adults and histopathologically characterized by inflammation, demyelination and gliosis. It is considered as a CD4+ T cell-mediated disease, but also a disease-promoting role of the innate immune system has been proposed, based e.g. on the observation that innate immune receptors modulate disease severity of experimental autoimmune encephalomyelitis. Recent studies of our group provided first evidence for a key role of the innate immune LPS receptor (CD14) in pathophysiology of experimental autoimmune encephalomyelitis. CD14-deficient experimental autoimmune encephalomyelitis mice showed increased clinical symptoms and enhanced infiltration of monocytes and neutrophils in brain and spinal cord. Methods: In the current study, we further investigated the causes of the disease aggravation by CD14-deficiency and examined T cell activation, also focusing on the costimulatory molecules CTLA-4 and CD28, and T cell migration capacity over the blood brain barrier by FACS analysis, in vitro adhesion and transmigration assays. Results: In the results, we observed a significantly increased migration of CD14-deficient lymphocytes across an endothelial monolayer. In contrast, we did not see any differences in expression levels of TCR/CTLA-4 or TCR/CD28 and lymphocyte adhesion to endothelial cells from CD14-deficient compared to wildtype mice. Conclusion: The results demonstrate an important role of CD14 in migration of lymphocytes, and strengthen the importance of innate immune receptors in adaptive immune disorders, such as multiple sclerosis.
Serum miR-335 Level is Associated with the Treatment Response to Trans-Arterial Chemoembolization and Prognosis in Patients with Hepatocellular Carcinoma
Authors: Cui Liming , Hu Yue , Bai Bin , Zhang Shide
Published: August 2015

Aim: To identify the role of serum MicroRNA-335 (miR-335) in determining the treatment response to Trans-arterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC) and their prognosis after TACE. Methods: A total of 125 HCC patients were enrolled in this study. All these patients underwent TACE and the treatment response was evaluated. All patients were followed for prognosis analyses. Serum miR-335 levels immediate before and 30 days after TACE were determined. Results: HCC patients had significantly lower miR-335 levels than hepatitis patients and healthy controls. Lower serum miR-335 levels were closely associated with more progressive clinical features, including a higher mean serum AFP level, more vascular invasion, cirrhosis and larger tumor size. Response rates were higher in patients with high miR-335 compared to those with low miR-335 level. Patients with lower serum miR-335 levels had significantly poorer prognosis than patients with higher serum miR-335 levels. Conclusion: Our data suggest that serum miR-335 can be used as a molecular marker to predict the treatment response and clinical outcome in HCC patients receiving TACE.
Reflectance Confocal Microscopy Features of Focal Dermal Mucinosis Differ from Those Described for Basal Cell Carcinoma: Report of Two Cases
Authors: Fraga-Braghiroli Naiara Abreu , Merati Miesha , Rabinovitz Harold , Swanson David , Scope Alon
Published: August 2015

The purpose of this study was to describe the reflectance confocal microscopy (RCM) features of focal dermal mucinosis (FDM). The entity clinically and dermatoscopically mimics other diagnostic entities, most notably nonpigmented basal cell carcinoma. We describe two cases that highlight the dermatoscopic, RCM and histopathological attributes of FDM. RCM features such as dermal foci of dense collagen bundles oriented in the same direction, foci of haphazardly oriented thin collagen fibers separated by dark structureless areas and the absence of dark silhouettes and tumor islands are clues for FDM diagnosis. The FDM cases described here present consistent and particular RCM findings that appear to correlate well with the histopathological features of FDM. Therefore, RCM is a promising technology in diagnosing skin lesions and it use can avoid invasive procedures.
Plasma Levels of Soluble Interleukin-2 Receptor α
Authors: Durda Peter , Sabourin Jeremy , Lange Ethan M. , Nalls Mike A. , Mychaleckyj Josyf C. , Jenny Nancy Swords , Li Jin , Walston Jeremy , Harris Tamara B. , Psaty Bruce M. , Valdar William , Liu Yongmei , Cushman Mary , Reiner Alex P. , Tracy Russell P. , Lange Leslie A.
Published: August 2015

Objective—

Interleukin (IL) -2 receptor subunit α regulates lymphocyte activation, which plays an important role in atherosclerosis. Associations between soluble IL-2Rα (sIL-2Rα) and cardiovascular disease (CVD) have not been widely studied and little is known about the genetic determinants of sIL-2Rα levels.

Approach and Results—

We measured baseline levels of sIL-2Rα in 4408 European American (EA) and 766 African American (AA) adults from the Cardiovascular Health Study (CHS) and examined associations with baseline CVD risk factors, subclinical CVD, and incident CVD events. We also performed a genome-wide association study for sIL-2Rα in CHS (2964 EAs and 683 AAs) and further combined CHS EA results with those from two other EA cohorts in a meta-analysis (n=4464 EAs). In age, sex- and race- adjusted models, sIL-2Rα was positively associated with current smoking, type 2 diabetes mellitus, hypertension, insulin, waist circumference, C-reactive protein, IL-6, fibrinogen, internal carotid wall thickness, all-cause mortality, CVD mortality, and incident CVD, stroke, and heart failure. When adjusted for baseline CVD risk factors and subclinical CVD, associations with all-cause mortality, CVD mortality, and heart failure remained significant in both EAs and AAs. In the EA genome-wide association study analysis, we observed 52 single-nucleotide polymorphisms in the chromosome 10p15-14 region, which contains
IL2RA
,
IL15RA
, and
RMB17
, that reached genome-wide significance (
P
<5×10
−8
). The most significant single-nucleotide polymorphism was rs7911500 (
P
=1.31×10
−75
). The EA meta-analysis results were highly consistent with CHS-only results. No single-nucleotide polymorphisms reached statistical significance in the AAs.

Conclusions—

These results support a role for sIL-2Rα in atherosclerosis and provide evidence for multiple-associated single-nucleotide polymorphisms at chromosome 10p15-14.
MicroRNA-15b/16 Attenuates Vascular Neointima Formation by Promoting the Contractile Phenotype of Vascular Smooth Muscle Through Targeting YAP
Authors: Xu Fei , Ahmed Abu Shufian Ishtiaq , Kang Xiuhua , Hu Guoqing , Liu Fang , Zhang Wei , Zhou Jiliang
Published: August 2015

Objective—

To investigate the functional role of the microRNA (miR)-15b/16 in vascular smooth muscle (SM) phenotypic modulation.

Approach and Results—

We found that miR-15b/16 is one of the most abundant mRs expressed in contractile vascular smooth muscle cells (VSMCs). However, when contractile VSMCs get converted to a synthetic phenotype, miR-15b/16 expression is significantly reduced. Knocking down endogenous miR-15b/16 in VSMCs attenuates SM-specific gene expression but promotes VSMC proliferation and migration. Conversely, overexpression of miR-15b/16 promotes SM contractile gene expression while attenuating VSMC migration and proliferation. Consistent with this, overexpression of miR-15b/16 in a rat carotid balloon injury model markedly attenuates injury-induced SM dedifferentiation and neointima formation. Mechanistically, we identified the potent oncoprotein yes-associated protein (YAP) as a downstream target of miR-15b/16 in VSMCs. Reporter assays validated that miR-15b/16 targets YAP’s 3′ untranslated region. Moreover, overexpression of miR-15b/16 significantly represses YAP expression, whereas conversely, depletion of endogenous miR-15b/16 results in upregulation of YAP expression.

Conclusions—

These results indicate that miR-15b/16 plays a critical role in SM phenotypic modulation at least partly through targeting YAP. Restoring expression of miR-15b/16 would be a potential therapeutic approach for treatment of proliferative vascular diseases.
β
3
Integrin Promotes Long-Lasting Activation and Polarization of Vascular Endothelial Growth Factor Receptor 2 by Immobilized Ligand
Authors: Ravelli Cosetta , Grillo Elisabetta , Corsini Michela , Coltrini Daniela , Presta Marco , Mitola Stefania
Published: August 2015

Objective—

During neovessel formation, angiogenic growth factors associate with the extracellular matrix. These immobilized factors represent a persistent stimulus for the otherwise quiescent endothelial cells (ECs), driving directional EC migration and proliferation and leading to new blood vessel growth. Vascular endothelial growth factor receptor 2 (VEGFR2) is the main mediator of angiogenesis. Although VEGFR2 signaling has been deeply characterized, little is known about its subcellular localization during neovessel formation. Aim of this study was the characterization and molecular determinants of activated VEGFR2 localization in ECs during neovessel formation in response to matrix-immobilized ligand.

Approach and Results—

Here we demonstrate that ECs stimulated by extracellular matrix–associated gremlin, a noncanonical VEGFR2 ligand, are polarized and relocate the receptor in close contact with the angiogenic factor–enriched matrix both in vitro and in vivo. GM1 (monosialotetrahexosylganglioside)-positive planar lipid rafts, β
3
integrin receptors, and the intracellular signaling transducers focal adhesion kinase and RhoA (Ras homolog gene family, member A) cooperate to promote VEGFR2 long-term polarization and activation.

Conclusions—

A ligand anchored to the extracellular matrix induces VEGFR2 polarization in ECs. Long-lasting VEGFR2 relocation is closely dependent on lipid raft integrity and activation of β
3
integrin pathway. The study of the endothelial responses to immobilized growth factors may offer insights into the angiogenic process in physiological and pathological conditions, including cancer, and for a better engineering of synthetic tissue scaffolds to blend with the host vasculature.