Dual targeting of MTOR as a novel therapeutic approach for high-risk B-cell acute lymphoblastic leukemia

Children of Hispanic/Latino ancestry have increased incidence of high-risk B-cell acute lymphoblastic leukemia (HR B-ALL) with poor prognosis. This leukemia is characterized by a single-copy deletion of the IKZF1 (IKAROS) tumor suppressor and increased activation of the PI3K/AKT/mTOR pathway. This identifies mTOR as an attractive therapeutic target in HR B-ALL. Here, we report that IKAROS represses MTOR transcription and IKAROS' ability to repress MTOR in leukemia is impaired by oncogenic CK2 kinase. Treatment with the CK2 inhibitor, CX-4945, enhances IKAROS activity as a repressor of MTOR, resulting in reduced expression of MTOR in HR B-ALL. Thus, we designed a novel therapeutic approach that implements dual targeting of mTOR: direct inhibition of the mTOR protein (with rapamycin), in combination with IKAROS-mediated transcriptional repression of the MTOR gene (using the CK2 inhibitor, CX-4945). Combination treatment with rapamycin and CX-4945 shows synergistic therapeutic effects in vitro and in patient-derived xenografts from Hispanic/Latino children with HR B-ALL. These data suggest that such therapy has the potential to reduce the health disparity in HR B-ALL among Hispanic/Latino children. The dual targeting of oncogene transcription, combined with inhibition of the corresponding oncoprotein provides a paradigm for a novel precision medicine approach for treating hematological malignancies.

Cellular signaling and epigenetic regulation of gene expression in leukemia

Alterations in normal regulation of gene expression is one of the key features of hematopoietic malignancies. In order to gain insight into the mechanisms that regulate gene expression in these diseases, we dissected the role of the Ikaros protein in leukemia. Ikaros is a DNA-binding, zinc finger protein that functions as a transcriptional regulator and a tumor suppressor in leukemia. The use of ChIP-seq, RNA-seq, and ATAC-seq—coupled with functional experiments—revealed that Ikaros regulates both the global epigenomic landscape and epigenetic signature at promoter regions of its target genes. Casein kinase II (CK2), an oncogenic kinase that is overexpressed in leukemia, directly phosphorylates Ikaros at multiple, evolutionarily-conserved residues. Phosphorylation of Ikaros impairs the protein's ability to regulate both the transcription of its target genes and global epigenetic landscape in leukemia. Treatment of leukemia cells with a specific inhibitor of CK2 restores Ikaros function, resulting in cytotoxicity of leukemia cells. Here, we review the mechanisms through which the CK2-Ikaros signaling axis regulates the global epigenomic landscape and expression of genes that control cellular proliferation in leukemia.

Abstract 2620: Global epigenetic regulation of gene expression and tumor suppression in T-cell leukemia by Ikaros

Ikaros encodes a DNA-binding zinc finger protein that functions as a tumor suppressor. Loss of Ikaros function results in the development of high-risk B-cell and T-cell acute lymphoblastic leukemia. Previous studies suggested that Ikaros controls expression of its target genes via chromatin remodeling, and by forming complexes with the histone deacetylase, HDAC1. However, the mechanisms through which Ikaros regulates the global epigenetic signature in leukemia is unknown. We studied the role of Ikaros in regulating tumor suppression in Ikaros-defficient T-cell acute lymphoblastic leukemia (T-ALL) cells. The re-introduction of Ikaros at physiological levels via retroviral transduction into T-ALL cells, results in a cessation of cellular proliferation and cell cycle arrest within 4 days. To determine the dynamics of Ikaros-mediated epigenetic regulation of gene expression in T-ALL, we performed ChIP-seq of Ikaros, HDAC1, and histone modifications, along with microarray and ATAC-seq in wild-type T-ALL (that lacks Ikaros), and during each of 3 days following the re-introduction of Ikaros. Our results demonstrated that Ikaros directly regulates the global epigenomic landscape including genome wide de novo formation of enhancers in T-ALL. Further analysis showed that Ikaros induces the re-distribution of HDAC1 via direct recruitment of HDAC1 to promoter and enhancer regions of different target genes resulting in their transcriptional repression. Expression analysis identified a large number of novel signaling pathways that are directly regulated by Ikaros and HDAC1, and are responsible for the cessation of proliferation and the cell cycle arrest of T-ALL cells. Our results identified novel functions of Ikaros in the epigenetic regulation of gene expression and tumor suppression in T-ALL.

Citation Format: Yali Ding, Bo Zhang, Jonathon L. Payne, Kimberly J. Payne, Chunhua Song, Chandrika Gowda, Soumya Iyer, Pavan K. Dhanyamraju, Dhimant Desai, Suming Huang, Feng Yue, Sinisa Dovat. Global epigenetic regulation of gene expression and tumor suppression in T-cell leukemia by Ikaros [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2620.

Ikaros tumor suppressor function includes induction of active enhancers and super-enhancers along with pioneering activity

Ikaros encodes a transcription factor that functions as a tumor suppressor in T-cell acute lymphoblastic leukemia (T-ALL). The mechanisms through which Ikaros regulates gene expression and cellular proliferation in T-ALL are unknown. Re-introduction of Ikaros into Ikaros-null T-ALL cells resulted in cessation of cellular proliferation and induction of T-cell differentiation. We performed dynamic, global, epigenomic and gene expression analyses to determine the mechanisms of Ikaros tumor suppressor activity. Our results identified novel Ikaros functions in the epigenetic regulation of gene expression: Ikaros directly regulates de novo formation and depletion of enhancers, de novo formation of active enhancers and activation of poised enhancers; Ikaros directly induces the formation of super-enhancers; and Ikaros demonstrates pioneering activity by directly regulating chromatin accessibility. Dynamic analyses demonstrate the long-lasting effects of Ikaros DNA binding on enhancer activation, de novo formation of enhancers and super-enhancers, and chromatin accessibility. Our results establish that Ikaros’ tumor suppressor function occurs via global regulation of the enhancer and super-enhancer landscape and through pioneering activity. Expression analysis identified a large number of novel signaling pathways that are directly regulated by Ikaros and Ikaros-induced enhancers, and that are responsible for the cessation of proliferation and induction of T-cell differentiation in T-ALL cells.

Abstract 2537: Regulation of LMO2 oncogene expression in high-risk B-cell acute lymphoblastic leukemia

LIM domain only protein 2 (LMO2) is an oncogene that is overexpressed in a subset of B-cell acute lymphoblastic leukemia (B-ALL). The mechanisms that regulate LMO2 expression in B-ALL are still unknown. Here, we show that transcription of LMO2 in B-ALL is regulated by Ikaros, a tumor suppressor protein, which is encoded by the IKZF1 gene, and whose deletion is associated with development of high-risk B-ALL. The use of global chromatin immunoprecipitation coupled with the next-generation sequencing (ChIP-seq) studies in primary human B-ALL cells and in cell lines revealed a strong Ikaros occupancy at the promoter of the LMO2 gene. Ikaros binding to the LMO2 promoter was confirmed by quantitative chromatin immunoprecipitation (qChIP). We tested the role of Ikaros in regulating LMO2 transcription in B-ALL using gain-of-function and loss-of-function experiments. A luciferase reporter assay with the LMO2 promoter showed that Ikaros directly represses LMO2 transcription. Overexpression of Ikaros in B-ALL via retroviral transduction was associated with strongly reduced expression of LMO2. Furthermore, Ikaros knock-down with shRNA, resulted in increased transcription of LMO2 in B-ALL cells. These results suggest that Ikaros represses transcription of LMO2 in B-ALL. Since Ikaros' function in B-ALL is negatively regulated by pro-oncogenic Casein Kinase II (CK2), we tested whether CK2 inhibition affects Ikaros-mediated repression of LMO2. Both molecular inhibition with shRNA, and pharmacological inhibition of CK2 with a specific CK2 inhibitor, CX-4945, resulted in reduced expression of LMO2. Inhibition of CK2 was also associated with increased Ikaros occupancy at the LMO2 promoter. In high-risk B-ALL that have deletion of a single copy of the IKZF1 gene, Ikaros does not bind to the LMO2 promoter. Treatment of primary B-ALL cells that have IKZF1 haploinsufficiency restores Ikaros binding to the LMO2 promoter and results in reduced LMO2 expression. In conclusion, our data demonstrate that Ikaros and CK2 regulate transcription and overall expression of the LMO2 oncogene in B-ALL. Our results identify a novel mechanism of therapeutic action of CK2 inhibitors in high-risk B-ALL—repression of LMO2 expression via restoration of Ikaros' tumor suppressor function.

Citation Format: Yali Ding, Jonathon L. Payne, Shriya Kane, Elanora Dovat, Mario Soliman, Chunhua Song, Sinisa Dovat. Regulation of LMO2 oncogene expression in high-risk B-cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2537.

Abstract 1513: Epigenetic regulation of CD117 expression in B-cell acute lymphoblastic leukemia by Ikaros and histone deacetylase HDAC1

The type III receptor tyrosine kinase, CD117, functions as a receptor for stem cell factor (SCF) and is encoded by the c-kit gene. During hematopoiesis, CD117 is normally expressed in hematopoietic stem cells, multipotent progenitors, common lymphoid progenitors, and early-stage thymocytes. Overexpression and/or activating mutations of c-kit have been demonstrated in acute myeloid leukemia (AML), early T-cell precursor acute lymphoblastic leukemia (ETP-ALL), and B-cell acute lymphoblastic leukemia (B-ALL). It has been suggested that increased expression of CD117 is associated with stem-like phenotype and worse clinical outcomes in AML and T-ALL. The regulation of expression of c-kit in leukemia is still largely unknown. Here we report that transcription of c-kit in B-ALL is regulated by the Ikaros tumor suppressor protein and histone deacetylase HDAC1. Global genome-wide binding studies using ChIP-seq, demonstrate the occupancy of both Ikaros and HDAC1 at the promoter of the c-kit gene in B-ALL cells. Ikaros and HDAC1 binding to the c-kit promoter was confirmed by quantitative chromatin immunoprecipitation (qChIP). Overexpression of Ikaros via retroviral transduction results in reduced transcription of c-kit in B-ALL cells. Consistent with this, Ikaros knock-down with shRNA results in increased transcription of c-kit in B-ALL. These data suggest that Ikaros represses transcription of c-kit. Ikaros overexpression was associated with increased HDAC1 occupancy while Ikaros knock-down resulted in reduced HDAC1 binding to the promoter of the c-kit gene. We tested whether Ikaros-mediated transcriptional repression of c-kit requires HDAC1 activity. Results showed that inhibition of HDAC1 activity with a pan-histone deacetylase inhibitor, trichostatin (TSA), or a specific HDAC1 inhibitor, MS-275, abolishes Ikaros' ability to repress c-kit transcription in luciferase reporter assays. Molecular inhibition of HDAC1 with shRNA confirmed that HDAC1 activity is essential for Ikaros-mediated transcriptional repression of c-kit. A serial qChIP assay spanning the c-kit promoter was used to analyze the epigenetic changes that are associated with Ikaros and HDAC1 binding at the c-kit promoter. Results showed that increased Ikaros and HDAC1 occupancy at the c-kit promoter in B-ALL cells results in enrichment for the markers of the repressive chromatin, H3K9me3 and H3K27me3, as well as reduced occupancy of H3K9ac, a marker of active chromatin. In conclusion, the presented results show that the expression of c-kit in B-ALL is regulated at the transcriptional level by Ikaros and HDAC1 via chromatin remodeling. These data provide a novel insight into the role of Ikaros in both tumor suppression and transcriptional regulation of gene expression in B-cell acute lymphoblastic leukemia.

Citation Format: Shriya Kane, Jonathon L. Payne, Mario Soliman, Chandrika Gowda, Meixan Xiang, Chunhua Song, Kimberly J. Payne, Sinisa Dovat. Epigenetic regulation of CD117 expression in B-cell acute lymphoblastic leukemia by Ikaros and histone deacetylase HDAC1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1513.

Abstract 2527: Regulation of mitotic progression in T-cell acute lymphoblastic leukemia by the Ikaros tumor suppressor

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that represents a therapeutic challenge. Next-generation sequencing revealed that a subset of high-risk T-ALL which is associated with poor prognosis harbor inactivating mutations or deletion of one allele of the IKZF1 tumor suppressor. The IKZF1 gene encodes the Ikaros protein that functions as a regulator of transcription and a tumor suppressor. However, the molecular mechanism of Ikaros' tumor suppressor function in T-ALL is unclear. The use of quantitative chromatin immunoprecipitation (qChIP) determined that Ikaros binds to the promoter regions of Anaphase Promoting Complex Subunit 1 (ANAPC1) and Anaphase Promoting Complex Subunit 7 (ANAPC7) cell cycle genes in T-ALL primary cells in vivo. ANAPC1 and ANAPC7 genes encode proteins whose function is essential for progression through mitosis, as well as through the G1 phase of the cell cycle. Ikaros overexpression in T-ALL via retroviral transduction, results in reduced expression of ANAPC1and ANAPC7, as evidenced by quantitative RT-PCR (qRT-PCR) and Western blot. The luciferase reporter assay further confirmed Ikaros' function as a transcriptional repressor of ANAPC1 and ANAPC7. The knock-down of Ikaros with shRNA in T-ALL resulted in increased transcription of ANAPC1 and ANAPC7, as evidenced by qRT-PCR. These data suggest that Ikaros can regulate mitotic progression in T-ALL by repressing transcription of ANAPC1 and ANAPC7 genes. Next, we studied the mechanisms that regulate Ikaros' ability to repress ANAPC1 and ANAPC7 in T-ALL. Ikaros' function as a transcriptional repressor is regulated by Casein Kinase II (CK2). CK2 is overexpressed in hematopoietic malignancies and increased expression of CK2 results in T-ALL in murine models. We tested the effect of CK2 inhibition on Ikaros' ability to regulate transcription of ANAPC1 and ANAPC7 in human T-ALL. Molecular inhibition of CK2 with shRNA against the CK2 catalytic subunit resulted in reduced transcription of ANAPC1 and ANAPC7, as evidenced by qRT-PCR. This was associated with increased DNA-binding of Ikaros to the promoters of ANAPC1 and ANAPC7, as evidenced by qChIP. These data suggest that CK2 impairs Ikaros' ability to transcriptionally repress ANAPC1 and ANAPC7 and to regulate mitotic progression in T-ALL. Inhibition of CK2 enhances transcriptional repression of ANAPC1 and ANAPC7 by Ikaros, resulting in the cell cycle arrest of T-ALL. In conclusion, our results show that mitotic progression in T-ALL is controlled by transcriptional regulation of ANAPC1 and ANAPC7 by Ikaros. Overexpression of CK2 impairs Ikaros' ability to repress ANAPC1 and ANAPC7 expression, which contributes to deregulation of the control of mitotic progression in T-ALL. Results suggest the novel therapeutic mechanism of CK2 inhibitors for treatment of T-ALL.

Citation Format: Jonathon L. Payne, Elanora Dovat, Mario Soliman, Chunhua Song, Sinisa Dovat. Regulation of mitotic progression in T-cell acute lymphoblastic leukemia by the Ikaros tumor suppressor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2527.

Abstract 1512: Regulation of the CDC42 signaling pathway by IKZF1 in T-cell acute lymphoblastic leukemia

The IKZF1 gene encodes Ikaros—a DNA-binding, Kruppel-like zinc finger protein that functions as a tumor suppressor in T-cell acute lymphoblastic leukemia (T-ALL). Ikaros regulates transcription of a large number of genes that are involved in control of cellular proliferation. However, the molecular mechanisms through which Ikaros regulates proliferation of T-ALL cells are still unknown. The use of quantitative chromatin immunoprecipitation (qChIP) showed that Ikaros binds to the promoter regions of CDC42 in vivo in primary T-ALL patient samples as well as in T-ALL cell lines. Ikaros overexpression in B-ALL cells via retroviral transduction results in decreased transcription of CDC42, as evidenced by qRT-PCR and Western blot. The luciferase reporter assay showed that Ikaros represses CDC42 transcription by directly binding to its promoter. The shRNA-mediated knock-down of Ikaros in T-ALL resulted in increased expression of CDC42. These results suggest that Ikaros functions as a transcriptional repressor of CDC42 in T-ALL. Next, we studied the upstream signaling pathways that regulate Ikaros-mediated control of CDC42 transcription in T-ALL. Because Ikaros activity in leukemia is regulated via direct phosphorylation by Casein Kinase II (CK2), we tested the effect of CK2 inhibition on Ikaros-mediated regulation of CDC42 expression. Treatment of T-ALL cells with a specific CK2 inhibitor, CX-4945, resulted in reduced expression of CDC42 in T-ALL cells. This was associated with an increase in DNA-binding of Ikaros to the promoter of the CDC42 gene. Ikaros knock-down restored high expression of CDC42 in T-ALL cells that were treated with CK2 inhibitors. These data suggest that transcriptional repression of the CDC42 gene by Ikaros is impaired in T-ALL due to increased CK2 activity and reduced Ikaros DNA-binding affinity toward the CDC42 gene promoter. Inhibition of CK2 restores Ikaros function and results in transcriptional repression of the CDC42 gene. In conclusion, our results suggest that Ikaros regulates CDC42 signaling pathway via transcriptional repression of the small GTPase, CDC42, in T-ALL. Ikaros-mediated repression of CDC42 in T-ALL is negatively regulated by CK2. These results suggest that regulation of CDC42 expression is one of the mechanisms through which Ikaros regulates cellular proliferation in T-ALL.

Citation Format: Mario Soliman, Chunhua Song, Jonathon L. Payne, Zheng Ge, Chandrika Gowda, Yali Ding, Kimberly J. Payne, Sinisa Dovat. Regulation of the CDC42 signaling pathway by IKZF1 in T-cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1512.

Ikaros regulation of the BCL6/BACH2 axis and its clinical relevance in acute lymphoblastic leukemia

B-Cell CLL/Lymphoma 6 (BCL6) is a proto-oncogene that is highly expressed in acute lymphoblastic leukemia (ALL). BTB and CNC Homology 1 Basic Leucine Zipper Transcription Factor 2 (BACH2) is a suppressor of transcription. The BACH2-BCL6 balance controls selection at the pre-B cell receptor checkpoint by regulating p53 expression. However, the underlying mechanism and the clinical relevance of the BCL6/BACH2 axis are unknown. Here, we found that Ikaros, a tumor suppressor encoded by IKZF1, directly binds to both the BCL6 and BACH2 promoters where it suppresses BCL6 and promotes BACH2 expression in B-cell ALL (B-ALL) cells. Casein kinase 2 (CK2) inhibitors increase Ikaros function thereby inhibiting BCL6 and promoting BACH2 expression in an Ikaros-dependent manner. We also found that the expression of BCL6 is higher while BACH2 expression is lower in patients with B-ALL than normal bone marrow control. High BCL6 and low BACH2 expression is associated with high leukemic cell proliferation, unfavorable clinical and laboratory features, and inferior outcomes. Moreover, IKZF1 deletion is associated with high BCL6 and low BACH2 expression in B-ALL patients. CK2 inhibitors increase Ikaros binding to the promoter of BCL6 and BACH2 and suppress BCL6 while promoting BACH2 expression in the primary B-ALL cells. Our data indicates that Ikaros regulates expression of the BCL6/BACH2 axis in B-ALL. High BCL6 and low BACH2 expression are associated with Ikaros dysregulation and have a potential effect on the development of B-ALL.

Casein Kinase II (CK2) as a Therapeutic Target for Hematological Malignancies

BACKGROUND

Casein kinase II (CK2) is a pro-oncogenic protein, which is emerging as a promising therapeutic target in cancer. Recent studies have revealed an important role for CK2 in tumorigenesis. High levels of CK2 are noted in many malignancies including leukemia. Use of CK2 inhibitors in various malignancies including breast, prostate, and lung cancer are being tested. Although many CK2 inhibitors exist, only a few have emerged as selective inhibitors that are potent and effective. CX-4945 is a selective, orallybioavailable small molecule inhibitor, which has shown encouraging results in pre-clinical models of leukemia.

METHODS

In this review we will elaborate on the structure and physiological function of the CK2 protein as well as its role in cancer. We will review, in depth, the role of CK2 in leukemia and its mechanisms of tumorigenesis via phosphorylation of the tumor suppressor protein Ikaros. We will discuss both the importance of Ikaros in leukemia suppression and the restoration of Ikaros' tumor suppressor function after CK2 inhibition by CX-4945 (a CK2-specific inhibitor).

RESULTS

CK2 is an oncogene that is overexpressed in hematological malignancies. In high risk Pre-B ALL, CK2 phosphorylates Ikaros tumor suppressor and promotes leukemogenesis. Inhibition of CK2 using CX4945 restores Ikaros function and leads to anti leukemic effects in vitro and in pre-clinical leukemia models.

CONCLUSION

CK2 is an attractive target in treatment of various cancers. Currently only a few specific CK2 inhibitors are available. Preclinical studies using CK2 inhibitor, CX4945 in high risk pediatric leukemias have shown promising results and warrants further testing in other types of leukemia.

Abstract 5542: Regulation of cell cycle control in T-cell acute lymphoblastic leukemia by Ikaros and Casein Kinase II

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that represents a therapeutic challenge. Next-generation sequencing revealed that a subset of T-ALL harbors inactivating mutations or deletion of one allele of the IKZF1 tumor suppressor. These data suggest that IKZF1 acts as a tumor suppressor in T-ALL. The IKZF1 gene encodes the Ikaros protein that functions as a regulator of transcription and a tumor suppressor in B cell acute lymphoblastic leukemia. However, the molecular mechanism of Ikaros tumor suppressor function in T-ALL is unclear. Using quantitative chromatin immunoprecipitation (qChIP), we determined that Ikaros binds to the promoter regions of the CDC2 and CDC7 cell cycle genes in primary T-ALL cells in vivo. Gain-of function experiments showed that Ikaros overexpression in T-ALL results in reduced expression of CDC2 and CDC7, as evidenced by quantitative RT-PCR (qRT-PCR) and Western blot. The knock-down of Ikaros with shRNA in T-ALL cells resulted in increased transcription of CDC2 and CDC7 as indicated by qRT-PCR. These data suggest that Ikaros can regulate cell cycle progression in T-ALL by repressing transcription of the CDC2 and CDC7 genes. Next, we studied the mechanisms that regulate Ikaros’ ability to repress CDC2 and CDC7 in T-ALL. Ikaros function as a transcriptional repressor is regulated by Casein Kinase II (CK2). CK2 is overexpressed in hematopoietic malignancies and increased expression of CK2 results in T-ALL in murine models. We tested the effect of CK2 inhibition on Ikaros’ ability to regulate transcription of CDC2 and CDC7 in human T-ALL. Molecular inhibition of CK2 with shRNA against the CK2 catalytic subunit resulted in reduced transcription of CDC2 and CDC7, as evidenced by qRT-PCR. This was associated with increased DNA-binding of Ikaros to promoters of CDC2 and CDC7, as shown by qChIP. These data suggest that CK2 impairs Ikaros’ ability to transcriptionally repress CDC2 and CDC7 and to regulate cell cycle progression in T-ALL. Inhibition of CK2 enhances transcriptional repression of CDC2 and CDC7 by Ikaros, resulting in improved control of cell cycle progression in T-ALL. In conclusion, our results show that control of cell cycle progression in T-ALL occurs trough Ikaros-mediated transcriptional regulation of CDC2 and CDC7. Overexpession of CK2 impairs Ikaros ability to repress CDC2 and CDC7 expression, which contributes to deregulation of cell cycle control in T-ALL. Results suggest a potential mechanism of therapeutic action of CK2 inhibitors for the treatment of T-ALL.

Note: This abstract was not presented at the meeting.

Citation Format: Mario A. Soliman, Tommy Hu, Malika Kapadia, Elanora Dovat, Yali Ding, Chunhua Song, Jonathon L. Payne, Sinisa Dovat. Regulation of cell cycle control in T-cell acute lymphoblastic leukemia by Ikaros and Casein Kinase II [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5542. doi:10.1158/1538-7445.AM2017-5542

Regulation of cellular proliferation in acute lymphoblastic leukemia by Casein Kinase II (CK2) and Ikaros

The IKZF1 gene encodes the Ikaros protein, a zinc finger transcriptional factor that acts as a master regulator of hematopoiesis and a tumor suppressor in leukemia. Impaired activity of Ikaros is associated with the development of high-risk acute lymphoblastic leukemia (ALL) with a poor prognosis. The molecular mechanisms that regulate Ikaros' function as a tumor suppressor and regulator of cellular proliferation are not well understood. We demonstrated that Ikaros is a substrate for Casein Kinase II (CK2), an oncogenic kinase that is overexpressed in ALL. Phosphorylation of Ikaros by CK2 impairs Ikaros' DNA-binding ability, as well as Ikaros' ability to regulate gene expression and function as a tumor suppressor in leukemia. Targeting CK2 with specific inhibitors restores Ikaros' function as a transcriptional regulator and tumor suppressor resulting in a therapeutic, anti-leukemia effect in a preclinical model of ALL. Here, we review the genes and pathways that are regulated by Ikaros and the molecular mechanisms through which Ikaros and CK2 regulate cellular proliferation in leukemia.

The influence of the biological pump on ocean chemistry: implications for long-term trends in marine redox chemistry, the global carbon cycle, and marine animal ecosystems

The net export of organic matter from the surface ocean and its respiration at depth create vertical gradients in nutrient and oxygen availability that play a primary role in structuring marine ecosystems. Changes in the properties of this 'biological pump' have been hypothesized to account for important shifts in marine ecosystem structure, including the Cambrian explosion. However, the influence of variation in the behavior of the biological pump on ocean biogeochemistry remains poorly quantified, preventing any detailed exploration of how changes in the biological pump over geological time may have shaped long-term shifts in ocean chemistry, biogeochemical cycling, and ecosystem structure. Here, we use a 3-dimensional Earth system model of intermediate complexity to quantitatively explore the effects of the biological pump on marine chemistry. We find that when respiration of sinking organic matter is efficient, due to slower sinking or higher respiration rates, anoxia tends to be more prevalent and to occur in shallower waters. Consequently, the Phanerozoic trend toward less bottom-water anoxia in continental shelf settings can potentially be explained by a change in the spatial dynamics of nutrient cycling rather than by any change in the ocean phosphate inventory. The model results further suggest that the Phanerozoic decline in the prevalence ocean anoxia is, in part, a consequence of the evolution of larger phytoplankton, many of which produce mineralized tests. We hypothesize that the Phanerozoic trend toward greater animal abundance and metabolic demand was driven more by increased oxygen concentrations in shelf environments than by greater food (nutrient) availability. In fact, a lower-than-modern ocean phosphate inventory in our closed system model is unable to account for the Paleozoic prevalence of bottom-water anoxia. Overall, these model simulations suggest that the changing spatial distribution of photosynthesis and respiration in the oceans has exerted a first-order control on Earth system evolution across Phanerozoic time.

Limited role of functional differentiation in early diversification of animals

The origin of most animal phyla and classes during the Cambrian explosion has been hypothesized to represent an ‘early burst’ of evolutionary exploration of functional ecological possibilities. However, the ecological history of marine animals has yet to be fully quantified, preventing an assessment of the early-burst model for functional ecology. Here we use ecological assignments for 18,621 marine animal genera to assess the relative timing of functional differentiation versus taxonomic diversification from the Cambrian to the present day. We find that functional diversity increased more slowly than would be expected given the history of taxonomic diversity. Contrary to previous inferences of rapid ecological differentiation from the early appearances of all well-fossilized phyla and classes, explicit coding of functional characteristics demonstrates that Cambrian genera occupied comparatively few modes of life. Functional diversity increased in the Ordovician and, especially, during the recoveries from the end-Permian and end-Cretaceous mass extinctions. Permanent shifts in the relationship between functional and taxonomic diversity following the era-bounding extinctions indicates a critical role for these biotic crises in coupling taxonomic and functional diversity.

Functional differentiation and taxonomic diversity are related in modern ecosystems. Here, the authors show that functional differentiation lags behind taxonomic diversification early in the evolutionary history of marine animals and that important shifts in this relationship occur at major mass extinction events.

Abstract 409: Regulation of chromatin remodeling in leukemia by Ikzf1 and Casein Kinase II

Ikzf1 (Ikaros) encodes a zinc finger protein that binds DNA and regulates gene expression via chromatin remodeling. The loss of Ikaros activity due to genetic or functional inactivation results in leukemia with a poor prognosis. The goal of our project is to determine the mechanism by which Ikaros regulates chromatin remodeling in human leukemia. Previous studies showed that Ikaros function in leukemia is controlled through its direct phosphorylation by Casein Kinase II (CK2). Treatment of leukemia cells with CK2 inhibitors results in enhanced Ikaros activity, which leads to cessation of cell growth. We have studied the mechanism by which inhibition of CK2 regulates Ikaros-induced epigenetic changes in leukemia. The human Nalm6 pre-B cell leukemia was treated with CK2 inhibitor, and the epigenetic signature of the histone modifications H3K9ac and H3K9me3 were determined using chromatin immunoprecipitation coupled with next generation sequencing (ChIP-SEQ). H3K9ac histone modification is associated with positive regulation of gene expression, while H3K9me3 is associated with the formation of heterochromatin and repression. The enrichment of particular histone modifications was confirmed by quantitative chromatin immunoprecipitation (qChIP). The results demonstrated that the inhibition of CK2 activity in leukemia results in a marked alteration in the epigenetic signature of both H3K9ac and H3K9me3 compared to untreated cells. This is associated with altered Ikaros binding to its target genes following CK2 inhibition. Current bioinformatics analysis is directed toward establishing a link between epigenetic modifications and Ikaros binding in leukemia. These results suggest that CK2 and Ikaros regulate gene transcription via epigenetic modifications and chromatin remodeling in leukemia.

Citation Format: Jonathon L. Payne, Carlos M. Casiano, Kimberly J. Payne, Justin Sloane, Elanora Dovat, Chunhua Song, Sinisa Dovat. Regulation of chromatin remodeling in leukemia by Ikzf1 and Casein Kinase II. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 409. doi:10.1158/1538-7445.AM2014-409

Antenatal prediction of postpartum depression with blood DNA methylation biomarkers

Postpartum depression (PPD) affects ∼10-18% of women in the general population and results in serious consequences to both the mother and offspring. We hypothesized that predisposition to PPD risk is due to an altered sensitivity to estrogen-mediated epigenetic changes that act in a cell autonomous manner detectable in the blood. We investigated estrogen-mediated epigenetic reprogramming events in the hippocampus and risk to PPD using a cross-species translational design. DNA methylation profiles were generated using methylation microarrays in a prospective sample of the blood from the antenatal period of pregnant mood disorder patients who would and would not develop depression postpartum. These profiles were cross-referenced with syntenic locations exhibiting hippocampal DNA methylation changes in the mouse responsive to long-term treatment with 17β-estradiol (E2). DNA methylation associated with PPD risk correlated significantly with E2-induced DNA methylation change, suggesting an enhanced sensitivity to estrogen-based DNA methylation reprogramming exists in those at risk for PPD. Using the combined mouse and human data, we identified two biomarker loci at the HP1BP3 and TTC9B genes that predicted PPD with an area under the receiver operator characteristic (ROC) curve (area under the curve (AUC)) of 0.87 in antenatally euthymic women and 0.12 in a replication sample of antenatally depressed women. Incorporation of blood count data into the model accounted for the discrepancy and produced an AUC of 0.96 across both prepartum depressed and euthymic women. Pathway analyses demonstrated that DNA methylation patterns related to hippocampal synaptic plasticity may be of etiological importance to PPD.

Abstract 1984: The Ikaros tumor suppressor regulates transcription of genes involved in cell signaling in human leukemia

The IKZF1 gene encodes Ikaros, a DNA binding zinc finger protein that is essential for normal hematopoietic differentiation. Deletion or mutation of Ikaros has been associated with a both T and B-cell acute lymphoblastic leukemia (ALL), as well as acute and chronic myelogenous leukemias (AML and CML). Deletion of an Ikaros allele has also been identified as a poor prognostic marker in childhood B-ALL. Thus, Ikaros is established as a major tumor suppressor in hematopoietic malignancies. The Ikaros protein can activate or repress target gene expression via chromatin remodeling. The specific mechanisms by which Ikaros exerts its tumor suppressor activities are unknown. We have defined genome-wide occupancy of Ikaros in human leukemia using ChIP-SEQ and identified a large number of potential Ikaros target genes. The quantitative Chromatin Immunoprecipitation assay (qChIP) was used to identify genes whose expression is directly regulated by Ikaros. Using this technique we show that Ikaros binds to the promoter region of a gene that is part of a pro-oncogenic pathway, as well as a tumor suppressor gene. Both genes are essential components of cell signaling pathways. The promoter regions of the two novel target genes were cloned into luciferase reporter constructs and used to transiently transfect HEK 293T cells that were co-transfected with Ikaros or empty vector (as a control). Luciferase reporter assays demonstrate that Ikaros suppresses transcription of the gene that is involved in oncogenic transformation, while it positively regulates transcription of the tumor suppressor gene. In summary, we have identified two novel Ikaros target genes. Our results suggest that Ikaros exerts its tumor suppression function by regulating the expression of target genes involved in pro-oncogenic and tumor suppressor signaling in leukemia cells. These data identify mechanisms of the tumor suppressor activity of Ikaros in leukemia.

Citation Format: Jonathon L. Payne, Justin Sloane, Rebekka M. Bamert, Elanora Dovat, Hui Li, Marie Bulathsinghala, Chandrika Gowda, Chunhua Song, Sinisa Dovat. The Ikaros tumor suppressor regulates transcription of genes involved in cell signaling in human leukemia. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1984. doi:10.1158/1538-7445.AM2013-1984

Regulator of myeloid differentiation and function: The secret life of Ikaros

Ikaros (also known as Lyf-1) was initially described as a lymphoid-specific transcription factor. Although Ikaros has been shown to regulate hematopoietic stem cell renewal, as well as the development and function of cells from multiple hematopoietic lineages, including the myeloid lineage, Ikaros has primarily been studied in context of lymphoid development and malignancy. This review focuses on the role of Ikaros in myeloid cells. We address the importance of post-transcriptional regulation of Ikaros function; the emerging role of Ikaros in myeloid malignancy; Ikaros as a regulator of myeloid differentiation and function; and the selective expression of Ikaros isoform-x in cells with myeloid potential. We highlight the challenges of dissecting Ikaros function in lineage commitment decisions among lymphoid-myeloid progenitors that have emerged as a major myeloid differentiation pathway in recent studies, which leads to reconstruction of the traditional map of murine and human hematopoiesis.

Genome-wide linkage and follow-up association study of postpartum mood symptoms

OBJECTIVE

Family studies have suggested that postpartum mood symptoms might have a partly genetic etiology. The authors used a genome-wide linkage analysis to search for chromosomal regions that harbor genetic variants conferring susceptibility for such symptoms. The authors then fine-mapped their best linkage regions, assessing single nucleotide polymorphisms (SNPs) for genetic association with postpartum symptoms.

METHOD

Subjects were ascertained from two studies: the NIMH Genetics Initiative Bipolar Disorder project and the Genetics of Recurrent Early-Onset Depression. Subjects included women with a history of pregnancy, any mood disorder, and information about postpartum symptoms. In the linkage study, 1,210 women met criteria (23% with postpartum symptoms), and 417 microsatellite markers were analyzed in multipoint allele sharing analyses. For the association study, 759 women met criteria (25% with postpartum symptoms), and 16,916 SNPs in the regions of the best linkage peaks were assessed for association with postpartum symptoms.

RESULTS

The maximum linkage peak for postpartum symptoms occurred on chromosome 1q21.3-q32.1, with a chromosome-wide significant likelihood ratio Z score (Z(LR)) of 2.93 (permutation p=0.02). This was a significant increase over the baseline Z(LR) of 0.32 observed at this locus among all women with a mood disorder (permutation p=0.004). Suggestive linkage was also found on 9p24.3-p22.3 (Z(LR)=2.91). In the fine-mapping study, the strongest implicated gene was HMCN1 (nominal p=0.00017), containing four estrogen receptor binding sites, although this was not region-wide significant.

CONCLUSIONS

This is the first study to examine the genetic etiology of postpartum mood symptoms using genome-wide data. The results suggest that genetic variations on chromosomes 1q21.3-q32.1 and 9p24.3-p22.3 may increase susceptibility to postpartum mood symptoms.

The role of estrogen in mood disorders in women

Major depression is twice as common in women as men and depressive episodes appear to be more common in women with bipolar disorder. There is accumulating evidence that, in at least some women, reproductive-related hormonal changes may play a role in increasing the risk of depressive symptoms premenstrually, postpartum and in the perimenopausal period. In this review, the evidence for the role of hormonal fluctuations, specifically estrogen, in triggering depressive symptoms in a subgroup of women is summarized. In addition, the potential role of estrogen in triggering depressive symptoms via its effects on the serotonergic system, brain-derived neurotrophic factor and Protein Kinase C is reviewed.

Health-related quality of life after different types of solid organ transplantation

OBJECTIVE

To describe functional health and health-related quality of life (QOL) before and after transplantation; to compare and contrast outcomes among liver, heart, lung, and kidney transplant patients, and compare these outcomes with selected norms; and to explore whether physiologic performance, demographics, and other clinical variables are predictors of posttransplantation overall subjective QOL.

SUMMARY BACKGROUND DATA

There is increasing demand for outcomes analysis, including health-related QOL, after medical and surgical interventions. Because of the high cost, interest in transplantation outcomes is particularly intense. With technical surgical experience and improved immunosuppression, survival after solid organ transplantation has matured to acceptable levels. More sensitive measures of outcomes are necessary to evaluate further developments in clinical transplantation, including data on objective functional outcome and subjective QOL.

METHODS

The Karnofsky Performance Status was assessed objectively for patients before transplantation and up to 4 years after transplantation, and scores were compared by repeated measures analysis of variance. Subjective evaluation of QOL over time was obtained using the Short Form-36 (SF-36) and the Psychosocial Adjustment to Illness Scale (PAIS). These data were analyzed using multivariate and univariate analysis of variance. A summary model of health-related QOL was tested by path analysis.

RESULTS

Tools were administered to 100 liver, 94 heart, 112 kidney, and 65 lung transplant patients. Mean age at transplantation was 48 years; 36% of recipients were female. The Karnofsky Performance Status before transplantation was 37 +/- 1 for lung, 38 +/- 2 for heart, 53 +/- 3 for liver, and 75 +/- 1 for kidney recipients. After transplantation, the scores improved to 67 +/- 1 at 3 months, 77 +/- 1 at 6 months, 82 +/- 1 at 12 months, 86 +/- 1 at 24 months, 84 +/- 2 at 36 months, and 83 +/- 3 at 48 months. When patients were stratified by initial performance score as disabled or able, both groups merged in terms of performance by 6 months after liver and heart transplantation; kidney transplant patients maintained their stratification 2 years after transplantation. The SF-36 physical and mental component scales improved after transplantation. The PAIS score improved globally. Path analysis demonstrated a direct effect on the posttransplant Karnofsky score by time after transplantation and diabetes, with trends evident for education and preoperative serum creatinine level. Although neither time after transplantation nor diabetes was directly predictive of a composite QOL score that incorporated all 15 subjective domains, recent Karnofsky score and education level were directly predictive of the QOL composite score.

CONCLUSIONS

Different types of transplant patients have a different health-related QOL before transplantation. Performance improved after transplantation for all four types of transplants, but the trajectories were not the same. Subjective QOL measured by the SF-36 and the PAIS also improved after transplantation. Path analysis shows the important predictors of health-related QOL. These data provide clearly defined and widely useful QOL outcome benchmarks for different types of solid organ transplants.

Treadmill exercise during adenosine infusion is safe, results in fewer adverse reactions, and improves myocardial perfusion image quality

BACKGROUND

Combining low-level treadmill exercise with adenosine infusion may result in fewer bradyarrhythmic complications by increasing sympathetic tone and may improve myocardial perfusion image quality by decreasing background activity.

METHODS

Patients referred for outpatient pharmacologic stress myocardial perfusion imaging performed simultaneous treadmill exercise (mean 2.2 metabolic equivalents) throughout 6-minute adenosine infusion (adenosine-exercise n = 507). Patients unable to exercise and those with left bundle branch block received adenosine infusion alone (adenosine-nonexercise n = 286). Adverse reaction data were collected on all patients and compared by sex. Background-to-target activity was calculated in a blinded fashion on 200 randomly selected patients.

RESULTS

During the period from April 1996 to December 1998, 507 patients (64%) underwent adenosine-exercise testing, whereas 286 (36%) underwent adenosine-nonexercise testing. Hypotensive and arrhythmic (atrioventricular block, sinus bradycardia, and new onset atrial fibrillation or flutter) adverse reactions occurred less often during adenosine-exercise than during adenosine-nonexercise. Neither death nor myocardial infarction occurred in either group. In the adenosine-exercise group, 2.8% of patients experienced an adverse reaction versus 5.6% of the adenosine-nonexercise group (P = .04). The reduction in adverse reactions occurred in both men and women, although women had significantly more adverse reactions than men (5.7% vs 1.8%, P = .004). Liver/heart and gut/heart ratios were lower in the adenosine-exercise group (1.05+/-0.42 vs. 1.21+/-0.55 , P = .01; 0.61+/-0.21 vs. 0.69+/-0.24, P = .03, respectively).

CONCLUSIONS

Compared with adenosine infusion alone, combining low-level treadmill exercise with adenosine in outpatients is safe, better tolerated, and improves image quality. Women were more likely to experience adverse reactions than men.

The impact of a College of Nursing Retention Program on the graduation rates of nursing students

This study was designed to measure the impact of a College of Nursing's (CON) Retention Program on students enrolled in a baccalaureate degree nursing program. Within the last ten years, undergraduate nurses increasingly have utilized the CON retention program. These students traditionally face a number of barriers to their academic endeavors. This study was designed to assess the effect of the CON program on the barriers to academic success of students who entered the CON in the Fall classes of 1991, 1992 and 1993. The sample size was 320 students. The control group consisted of 137 students who received no intervention and the experimental group was comprised of 183 students who attended intervention sessions with the Retention Coordinator in the CON. It was hypothesized that the most successful students during this period (1991-1993) were the most frequent attendees of the CON retention program intervention sessions. The alternative hypothesis was that those persons who did not attend the sessions, but were still highly persistent and successful, were enrollees who had entered with high entrance credentials as demonstrated by the transfer grade point averages (GPA). The results of this study indicated the need, use and value of this systematic approach to retention.

Relationship of cognitive and functional impairment to depressive features in Alzheimer's disease and other dementias

Patients with clinical diagnoses of Alzheimer's disease, vascular dementia, or undifferentiated dementia were rated on standardized measures of depression, cognitive impairment, and functional impairment. Logistic regression was used to evaluate the relationship between functional or cognitive impairment, as well as their interaction, and depressive features in each group. This analysis revealed notable differences by type of dementia. The results imply that the mechanisms underlying depression in Alzheimer's disease may be different from those in vascular and other types of dementia. These results also provide indicators to the clinician for further evaluation of depression in different dementia subtypes.

Experience with neoral versus sandimmune in primary liver transplant recipients

We compared results using Neoral versus Sandimmune, each in combination with steroid and azathioprine immunosuppression, in primary liver transplantation recipients. There were 15 patients in each group with similar demographic distributions. Intravenous cyclosporine was stopped at 4.3 +/- 1.9 days in the Neoral group vs 7.8 +/- 4.9 days in the Sandimmune group. (P < 0.025). Cyclosporine levels in the first 10 days were higher (mean 306 ng/ml vs 231 ng/ml) in the Neoral group than the Sandimmune group (P < 0.05). The Neoral dose was less than the Sandimmune dose (mean 5.5 ng/kg per day vs 7.9 ng/kg per day) to achieve these levels in that time period (P < 0.05). Two patients (13%) experienced three episodes of biopsy-proven rejection in the Neoral group compared to nine patients (60%) with 12 episodes of rejection in the Sandimmune group (P < 0.025). Incidences of neurological and renal complications were similar between the groups. Infections requiring treatment were also similar. Liver function, renal function, and marrow function, evaluated at days 7, 14, 21, 28, and 2, 4, 6, and 12 months post-transplant, were not different between the groups. In summary, shorter use of intravenous cyclosporine and quicker stabilization of trough cyclosporine levels was achieved with Neoral than with Sandimmune. In the early post-transplant period, higher levels with lower doses were achieved with Neoral than with Sandimmune. In our experience, the incidence of rejection was lower with Neoral than with Sandimmune. There were similar lengths of hospitalization, mortality, adverse events, retransplantation, and similar liver, renal, and marrow function up to 1 year post-transplantation. Because of this experience, we continued to use Neoral in a total of 59 primary liver transplant recipients. We have not used intravenous cyclosporine in the last 44 patients. Follow-up was a mean of 11.4 months, ranging from 1 to 27 months. The incidence of rejection was 24% in these 59 patients compared to our historical experience of 70% using Sandimmune.

Outcomes analysis in 100 liver transplantation patients

BACKGROUND

There is an increasing demand for outcomes analysis, including quality of life and financial analysis, following medical interventions and surgical procedures. We analyzed outcomes for 100 consecutive patients undergoing liver transplantation during a period of case management revision.

METHODS

Patient survival was calculated by Kaplan-Meier actuarial methods. The Karnofsky performance status was objectively assessed for surviving patients up to 6 years after transplantation and was evaluated by repeated measures analysis of variance and covariance. Subjective evaluation of quality of life over time was obtained using the Psychosocial Adjustment to Illness Scale. The correlations between time and scale were calculated. Financial data were accumulated from billing records.

RESULTS

Six-month, 1-year, 2-year, and 3- through 5-year survival was 86%, 84%, 83%, and 78%, respectively. Karnofsky performance status confirmed poor functional status preoperatively with a mean of 53 +/- 2, but significantly improving to 72 +/- 2 at 3 months, 80 +/- 2 at 6 months, 90 +/- 1 at 1 year, 92 +/- 1 at 2 years, 94 +/- 1 at 3 years, 96 +/- 1 at 4 years, and 97 +/- 1 at 5 years (P <0.001). Psychosocial Adjustment to Illness Scale scores demonstrated significant improvement following transplantation overall (r = -0.33), improving most in sexual relationships (r = -0.41), and domestic environment (r = -0.35; P <0.001). Median length of stay for the first half of the patients was 19 days declining to 11 days for the second half. Median hospital charges declined from $105,000 to $90,000.

CONCLUSIONS

Quality of life parameters assessed both by care givers (Karnofsky) and by patients (Psychosocial Adjustment to Illness Scale) improved dramatically following transplantation and over time, demonstrating that liver transplantation effectively restores a good quality of life. Outcomes can be improved while reducing length of stay and charges through modifications in case management.

Leukocyte lipid body formation and eicosanoid generation: cyclooxygenase-independent inhibition by aspirin

Lipid bodies, cytoplasmic inclusions that develop in cells associated with inflammation, are inducible structures that might participate in generating inflammatory eicosanoids. Cis-unsaturated fatty acids (arachidonic and oleic acids) rapidly induced lipid body formation in leukocytes, and this lipid body induction was inhibited by aspirin and nonsteroidal antiinflammatory drugs (NSAIDs). Several findings indicates that the inhibitory effect of aspirin and NSAIDs on lipid body formation was independent of cyclooxygenase (COX) inhibition. First, the non-COX inhibitor, sodium salicylate, was as potent as aspirin in inhibiting lipid body formation elicited by cis-fatty acids. Second, cis-fatty acid-induced lipid body formation was not impaired in macrophages from COX-1 or COX-2 genetically deficient mice. Finally, NSAIDs inhibited arachidonic acid-induced lipid body formation likewise in macrophages from wild-type and COX-1- and COX-2-deficient mice. An enhanced capacity to generate eicosanoids developed after 1 hr concordantly with cis-fatty acid-induced lipid body formation. Arachidonic and oleic acid-induced lipid body numbers correlated with the enhanced levels of leukotrienes B4 and C4 and prostaglandin E2 produced after submaximal calcium ionophore stimulation. Aspirin and NSAIDs inhibited both induced lipid body formation and the enhanced capacity for forming leukotrienes as well as prostaglandins. Our studies indicate that lipid body formation is an inducible early response in leukocytes that correlates with enhanced eicosanoid synthesis. Aspirin and NSAIDs, independent of COX inhibition, inhibit cis-fatty acid-induced lipid body formation in leukocytes and in concert inhibit the enhanced synthesis of leukotrienes and prostaglandins.

Soluble beta-amyloid induces Alzheimer's disease features in human fibroblasts and in neuronal tissues

It has been shown that K+ channels, Cp20 (a 20kD GTP-binding protein), and intracellular calcium release, play a key role in associative memory storage. These same elements have been shown to be altered in fibroblasts from Alzheimer's Disease (AD) patients. In addition, it has been shown that PKC, also implicated in memory storage and closely related to the above mentioned components, is also altered in AD fibroblasts. Moreover, beta-amyloid was capable of inducing an AD-like phenotype for K+ channels and Cp20 in otherwise normal fibroblasts, providing additional evidence for the potential involvement of these components in AD and suggesting a possible pathological consequence of soluble beta-amyloid elevation in AD. Preliminary evidence shows that comparable changes in potassium channel function are also present in human olfactory neuroblasts from AD patients. These results indicate that the observed changes not only occur in peripheral tissues such as fibroblasts, but also in neural tissue, the primary site of AD pathology.

Outcomes analysis for 50 liver transplant recipients: the Vanderbilt experience

Healthcare reform has mandated scrutiny of the fiscal aspects of patient care as well as medical outcomes. Therefore, we reviewed our experience with 50 liver transplant recipients from a multidisciplinary collaborative transplant team. From February 1991 to July 1994, of 175 patients referred, 75 were formally evaluated for transplantation; 56 (76%) of these patients were accepted for transplantation; 50 patients underwent 53 transplants. Operative mortality of 6 per cent, retransplantation rate of 6 per cent, 6-month actuarial survival of 88 per cent, 1-year survival of 86 per cent, and the 2 and 3-year survival of 83 per cent were unchanged over time. Quality of life evaluated by the Karnofsky Performance Status was a mean of 55 pretransplant, 72 at 3 months, 79 at 6 months, 84 at 1 year, 88 at 2 years, and 95 at 3 years, demonstrating improved general health and functional rehabilitation after transplantation. Psychosocial Adjustment to Illness Scale scores demonstrated significant improvement following transplantation, improving most dramatically in the vocation environment, domestic environment, and sexual relationship domains. Postoperative length of stay has declined with an average of 28 days in 1991, 22 days in 1992, 19 days in 1993, and 14 days in 1994. Average total hospital, organ procurement, and physician charges for the transplantation hospitalization was $165,000. Average 91-92 hospital charges were $154,000 and were reduced in 93-95 to $103,000 (P < .05). We found that charges and length of stay decreased over time, while the outcome and quality of patient care was maintained. We believe the collaborative practice, case management, and revised patient care protocols are responsible.

Mechanisms of platelet-activating factor-induced lipid body formation: requisite roles for 5-lipoxygenase and de novo protein synthesis in the compartmentalization of neutrophil lipids

Lipid bodies, lipid rich cytoplasmic inclusions, are characteristically abundant in vivo in leukocytes associated with inflammation. Because lipid bodies are potential reservoirs of esterified arachidonate and sites at which eicosanoid-forming enzymes may localize, we evaluated mechanisms of lipid body formation in neutrophils (PMN). Among receptor-mediated agonists, platelet activating factor (PAF), but not C5a, formyl-methyl-phenylalanine, interleukin 8, or leukotriene (LT) B4, induced the rapid formation of lipid bodies in PMN. This action of PAF was receptor mediated, as it was dose dependently inhibited by the PAF receptor antagonist WEB 2086 and blocked by pertussis toxin. Lipid body induction by PAF required 5-lipoxygenase (LO) activity and was inhibited by the 5-lipoxygenase-activating protein antagonist MK 886 and the 5-LO inhibitor zileuton, but not by cyclooxygenase inhibitors. Corroborating the dependency of PAF-induced lipid body formation on 5-LO, PMN and macrophages from wild-type mice, but not from 5-LO genetically deficient mice, formed lipid bodies on exposure to PAF both in vitro and in vivo within the pleural cavity. The 5-LO product inducing lipid body formation was not LTB4 but was 5(S)-hydroxyeicosatetraenoic acid [5(S)-HETE], which was active at 10-fold lower concentrations than PAF and was also inhibited by pertussis toxin but not by zileuton or WEB 2086. Furthermore, 5-HETE was equally effective in inducing lipid body formation in both wild-type and 5-LO genetically deficient mice. Both PAF- and 5(S)-HETE-induced lipid body formation were inhibited by protein kinase C (PKC) inhibitors staurosporine and chelerythrine, the phospholipase C (PLC) inhibitors D609 and U-73122, and by actinomycin D and cycloheximide. Prior stimulation of human PMN with PAF to form lipid bodies enhanced eicosanoid production in response to submaximal stimulation with the calcium ionophore A23187; and the levels of both prostaglandin (PG) E2 and LTB4 correlated with the number of lipid bodies. Furthermore, pretreatment of cells with actinomycin D or cycloheximide inhibited not only the induction of lipid body formation by PAF, but also the PAF-induced "priming" for enhanced PGE2 and LTB4 in PMN. Thus, the compartmentalization of lipids to form lipid bodies in PMN is dependent on specific cellular responses that can be PAF receptor mediated, involves signaling through 5-LO to form 5-HETE and then through PKC and PLC, and requires new protein synthesis. Since increases in lipid body numbers correlated with priming for enhanced PGE2 and LTB4 production in PMN, the induction of lipid bodies may have a role in the formation of eicosanoid mediators by leukocytes involved in inflammation.

CNS role evolution

THE CNS ROLE has been actualized in a variety of ways. Flexibility-inherent in the role-and the revolution in health care consciousness tend to place the CNS at risk for criticism regarding value to the organization. At Vanderbilt University Medical Center, a CNS task force evaluated the current reality of CNS practice and recommended role changes to include the financial analysis of patient care. After incorporating a financial perspective into our present practice, we have embarked on an interesting journey of post-Master's degree study, that of the tertiary care nurse practitioner. This practice option could elevated the clinical and financial aspects of providing cost-effective health care to a more autonomous role form; however, the transition has been challenging. Since 1990, the American Nurses Association has recommended that nursing school curricula change to meet the needs of the health care environment and provide increased career flexibility through creating one advanced degree incorporating both CNS and NP functions. Swiftly moving past differences and toward similarities will bridge the gap for advanced practice nurses in the future.

Immune modification and complications of immunosuppression

For transplant recipients, immunosuppression is necessary to prevent rejection. The type of immunosuppression varies according to the patient and institution; however, most patients receive double or triple drug regimens. Thus, thorough nursing assessment and intervention are essential throughout the transplant period. Research in this area continues, leading to a promising future for transplantation.

Flicker fusion thresholds and mental arousal

Investigated the finding of Busch and Wachholder that flicker fusion thresholds increase under conditions of mental activity and decrease during inactivity. Flicker fusion thresholds for each eye of 21 undergraduates were measured after 2-min. rests, then after the performance of a mathematical counting exercise, and then after another 2-min. rest. The average thresholds for both the right and left eyes were significantly higher following the counting exercise than after the rests. Features of the experiment included a training/screening session for the subjects to detect and correct “pseudothreshold” problems, and an automatic adjustment of the light frequency to minimize possible experimenter effects.

A Case of Replantation and the Result after Twelve Years

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The Origin and Growth of the Odontological Society: (President's Address)

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An Artificial Velum for Congenital Cleft Palate

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DISCUSSION ON WAR INJURIES OF THE JAW AND FACE

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An Unusual Case of Fracture of a Tooth

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A New Interdental Splint

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