bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptor Protein Lnk Inhibits C-Fms Mediated Macrophage Function
Authors: Gueller Saskia , Goodridge Helen S. , Xing Hongtao , Gery Sigal , Serve Hubert , Koeffler H. Phillip
Published: October 2019

The macrophage colony-stimulating factor receptor (c-Fms) plays an important role in proliferation, differentiation and survival of macrophages and is involved in the regulation of distinct macrophage functions. Interaction with the ligand M-CSF results in activation of the intracellular tyrosine kinase domain and phosphorylation of tyrosine residues, thereby creating binding sites for several molecules containing Src homology 2 (SH2) domains. One such protein is the adaptor Lnk that negatively regulates several hematopoietic cytokine receptors including MPL, EpoR and c-Kit. Lnk belongs to a family of proteins sharing several structural motifs including a SH2 domain and a pleckstrin homology domain. The SH2 domain is known to be essential for its inhibitory effect which can be abolished by the point mutation R392E. In this study, we investigated the ability of Lnk to interact and modulate the function of c-Fms. In order to determine if Lnk can bind to c-Fms, immunoprecipitation was performed with lysates from 293T cells co-transfected with the cDNAs for c-Fms and Lnk. Only after exposure to M-CSF, Lnk bound to c-Fms, and binding was dependent on an intact SH2 domain. To elucidate further if Lnk exhibits biological and functional effects on macrophages, we examined both in-vitro differentiated macrophages derived from the bone marrow and also macrophages harvested from peritoneum from Lnk deleted (KO) and wild type (WT) mice. These cells appeared to be at a similar stage of differentiation because expression levels of myeloid and macrophage surface markers such as F4/80, CD11b and CD11c were the same in both bone marrow-derived and peritoneum-derived macrophages from Lnk KO and WT mice. Clonogenic assays demonstrated that the number of M-CFUs in the bone marrow were elevated in Lnk KO as compared to WT mice. Furthermore, the M-CSF-induced phosphorylation of AKT in these Lnk KO macrophages was increased and prolonged compared to WT macrophages. This was associated with prominent up-regulation of c-Fms in macrophages from Lnk KO mice. We found that Lnk additionally had several functional effects on bone marrow-derived macrophages. Production of reactive oxygen species (ROS) was dramatically increased in a M-CSF-dependent manner in Lnk KO macrophages upon stimulation with zymosan. In addition, knock-out of Lnk led to altered cytokine production of macrophages: Stimulation with zymosan caused increased levels of TNFalpha and IL-6 in the KO cells, while bacterial lipoproteins (Pam3CSK4) decreased levels of TNFalpha in KO compared to WT macrophages. Last, Lnk inhibited M-CSF-induced migration of macrophages in the Boyden chamber as Lnk KO macrophages showed a significantly higher migration capacity than WT macrophages. In summary, we show for the first time that Lnk can bind to c-Fms and can blunt the stimulation of M-CSF. Modulation of levels of Lnk in macrophages may provide a unique therapeutic approach to increase innate host defenses.
Long-Term Outcome of AIDS-Related Lymphoma Treated with Abbreviated Cycles of EPOCH-RR: A Prospective Study of 40 Patients
Authors: Dunleavy Kieron , Little Richard , Wayne Alan S. , Grant Nicole , Pittaluga Stefania , Jaffe Elaine S. , Steinberg Seth , Yarchoan Robert , Carrasquillo Jorge A. , Janik John E. , Wilson Wyndham H.
Published: October 2019

We hypothesized that the addition of rituximab to EPOCH chemotherapy could improve tumor kill, allowing delivery of fewer cycles of treatment and therefore reducing toxicity. Patients received EPOCH-RR (in mg/m2/d – etoposide 50, vincristine 0.4 and doxorubicin 10 all CIV d 1–5; cyclophosphamide 750 mg IV d 5; prednisone 60 po days 1–5 and rituximab 375 IV d 1,5 and G-CSF sc d 6–15) every 21 days. Prophylactic IT methotrexate was administered and HAART was suspended during therapy. Cyclophosphamide was adjusted based on absolute neutrophil count (ANC) nadir. Response was assessed by CT and FDG-PET scan and patients received 1 cycle beyond CR for a minimum of 3 cycles. Characteristics of 40 enrolled patients are: median (range) age 42 (9–60) years; IPI 3 (0–4); ECOG PS 1 (1–4), CD4 count 222 (0–835) cells/mm3; HIV viral load 34,766 (0–6,080000) RNA copies/mL; male sex 35 (88%); LDH > N 27 (68%); stage IV 27 (68%) and histology diffuse large B-cell lymphoma (DLBCL) 32 (80%) and Burkitt lymphoma (BL) 8 (20%). Of 38 evaluable patients (2NE), median (range) number of cycles given is 3 (3–5) with CR/CRu in 35 (92%) and PR in 1 (3%) patients. At 4 years median follow-up, PFS and OS are 86% and 70%, respectively. Eight patients with BL are in continuous CR. For patients with CD4 > and < 100 cells/mm3, PFS is 96% and 69%, respectively. IPI did not impact OS and PFS. Early PET scanning (after cycle 2) had a high negative predictive value (100%) but low positive predictive value (20%). Fever/neutropenia occurred on 30%, ANC < 500/mm3 on 40%, and platelets < 50,000/mm3 on 23% of cycles. EPOCH-RR was associated with less CD4 loss - median 128 cells/mm3 (range +154 to −639) compared to historical data with EPOCH alone (median 189 cells/mm3 (range +19 to −973). Patients with CD4 < 100/mm3 had good tumor control, but OS was only 31% due to late deaths from advanced AIDS. Patients with CD4 counts > 100/mm3 had an extremely good PFS and OS. The addition of rituximab did not appear to cause serious infection related complications or deaths. However, one treatment-related death occurred from complications of mycobacterium avium intercellulare. Abbreviated EPOCH-RR is highly effective and tolerable in ARL and enables the administration of fewer treatment cycles (median 3 versus 6). PET scanning has a very high negative but low positive predictive value for subsequent relapse, possibly due to HIV associated PET changes. Accrual continues.
Combined Epigenetic Therapy with the Novel Histone Methyl Transferase EZH2 Inhibitor 3-Deazaneplanocin and Histone Deacetylase Inhibitor Panobinostat Exerts Synergistic Activity against Human Mantle Cell Lymphoma Cells
Authors: Fiskus Warren , Wang Yongchao , Jillella Anand , Johnston Pace , Joshi Rajeshree , Rao Rekha , Sotomayor Eduardo , Tao Jianguo , Atadja Peter , Marqez Victor , Bhalla Kapil N.
Published: October 2019

Lysine specific histone methylation and deacetylation and DNA hypermethylation are involved in the epigenetic silencing of tumor suppressor genes (TSG), e.g., p16 and JunB. The multi-protein complex PRC (polycomb repressive complex) 2 that contains the three core proteins EZH2, SUZ12 and EED, has intrinsic histone methyltransferase (HMTase) activity. This is mediated by the SET domain of EZH2, which induces tri-methylation (3Me) of lysine (K)-27 on histone H3, as well as promotes cell proliferation and aggressiveness of neoplastic cells. EZH2 is preferentially overexpressed in proliferating but not resting Mantle Cell Lymphoma (MCL) cells. In the present studies we demonstrate that treatment with the S-adenosylhomocysteine hydrolase inhibitor 3-Deazaneplanocin A (DZNep) dose-dependently (500 nM to 2.0 uM) depletes EZH2, SUZ12 and EED levels, as well as inhibits 3Me K27 on H3 while inducing K27 H3 acetylation. DZNep treatment also induces the levels of p21, p27, JunB and FBXO32, while depleting cyclin D1 and cyclin E levels in the cultured human MCL Jeko-1, MO2058 and Z138 cells and in primary patient-derived MCL cells. Treatment with DZNep induces PARP cleavage activity of the caspases and apoptosis in the cultured and primary MCL cells. DZNep promoted proteasomal degradation of EZH2 and SUZ12, since co-treatment with bortezpmib significantly restored EZH2 and SUZ12 levels in the MCL cells. We had previously reported that treatment with the pan-histone deacetylase (HDAC) inhibitor panobinostat (PS) (LBH589, Novartis Pharmaceutical Corp) depletes the levels of EZH2, SUZ12 and EED in cultured and primary AML cells (Mol Cancer Ther.2006; 5:3096). Within the PRC2 complex, EZH2 bound and recruited the DNA methyltransferases DNMT1, and treatment with PS also disrupted the interaction of EZH2 with DNMT1, attenuated DNMT1 levels and its binding to the EZH2-targeted gene promoters, e,g, JunB. Here, we also demonstrate that, PS treatment depletes DNMT1 levels and induces JunB levels in cultured MCL cells. As compared to treatment with either agent alone, co-treatment with DZNep and PS caused more depletion of EZH2 and SUZ12, but not of DNMT1, more induction of JunB, p21 and p27, as well as synergistically induced apoptosis of cultured MCL cells (combination indices < 1.0). Taken together, these findings indicate that DZNep and PS mediated targeting of EZH2 and the PRC2 complex is an effective epigenetic therapy of MCL, which also results in undermining several molecular determinants of MCL cell proliferation and survival. Additionally, combined epigenetic therapy with DZNep and PS exerts synergistic in vitro activity against human MCL cells, suggesting that this combination may be a promising novel treatment for MCL.
Selective Inhibition of CDK4 and CDK6 Primes Chemoresistant MCL Cells for Killing by Proteasome Inhibitor Bortezomib by Activating Cell Cycle-Coupled Apoptosis
Authors: Di Li berto Maurizio , Huang Xiangao , Chadburn Amy , Martin Peter , Niesvizky Ruben , Ely Scott , Leonard John P. , Kiang Selina Chen-
Published: October 2019

Mantle Cell Lymphoma (MCL) remains generally incurable, suggesting that more effective control of unrestrained tumor growth is essential. Loss of cell cycle control is a hallmark of cancer, in particular of MCL where cell cycle progression through G1 is accelerated due to elevation of cyclin-dependent kinase 4 (CDK4) and constitutive cyclin D1 expression. Thus, one rational approach to improve MCL therapy is to target CDK4/6 in combination with cytotoxic killing. Although success in targeting the cell cycle in cancer with broad-spectrum CDK inhibitors has been modest, PD 0332991, the only known CDK4/6-specific inhibitor with oral bioavailability, has been shown to selectively and potently inhibit CDK4/6 in MCL cells ex vivo. Additionally, in a proof-of-mechanism study in patients with recurrent MCL, we have found that PD 0332991 is well tolerated, and effective in inhibiting CDK4 and CDK6 and suppressing tumor growth in vivo. Of note, 50% of the patients (8/16) have achieved a stable disease for greater then 40 weeks (Leonard et al, abstract submitted to ASH 2008). These findings suggest that selective targeting of CDK4 and CDK6 with PD 0332991 is a promising therapy for MCL. To advance targeting of the cell cycle in cancer, we have developed two novel approaches to both inhibit tumor cell proliferation and activate cell cycle-coupled apoptosis in MCL. We show in primary MCL tumor cells and MCL cell lines by BrdU pulse labeling and DNA content analysis that selective inhibition of CDK4/6 with PD 0332991 leads to a complete G1 arrest, despite high level of c-Myc expression and extensive chromosomal abnormality. As PD 0332991 acts reversibly, removal of PD 0332991 immediately releases the G1 block and induces synchronous (>90%) G1-S cell cycle progression and S phase entry. This sensitizes chemoresistant MCL cells to killing by suboptimal doses of cytotoxic agents such as bortezomib, through activating cell cycle-coupled apoptosis during S phase entry. Synergistic killing of MCL cells by induction of cell cycle synchronization with PD 0332991 in combination with bortezomib is mediated by induction of mitochondrial membrane depolarization and activation of caspase-9. In a complementary study, we have demonstrated that selective targeting of CDK4 and CDK6 by PD 0332991 similarly primes chemoresistant primary myeloma cells for cytotoxic killing by activating cell cycle-coupled apoptosis, and induces synergistic tumor suppression in animal models. Selective targeting of CDK4 and CDK6 by PD 0332991 in combination with cytotoxic killing, therefore, represents a promising new strategy for cell cycle-based therapy for MCL and other hematopoietic malignancies.
Osteomyelosclerosis, Anemia and Extramedullary Hematopoiesis in Mice Deficient for the Transcription Factor NFAT (Nuclear Factor of Activated T Cells) c2
Authors: Kyttälä Satu , Bauer Wolfgang , Haase Michael , Habermann Ivonne , Ehninger Gerhard , Kiani Alexander
Published: October 2019

NFAT (Nuclear Factor of Activated T cells) is a family of five calcium-induced, calcineurin-dependent transcription factors, characterized as master regulators of inducible gene expression in T lymphocytes. In various tissues (including bone, cartilage and adipose tissue), NFAT factors have also been found to regulate processes of cellular adaptation and differentiation. NFAT family members are also expressed in human CD34+ hematopoietic progenitor cells as well as in mesenchymal stem cells; however, a biological function of NFAT in these cells, such as a role in hematopoietic differentiation, has not yet been described. To determine a potential role for NFAT in hematopoiesis, we characterized the steady-state hematopoiesis in NFATc2 knockout (KO) mice by analyzing peripheral blood, bone marrow and extramedullary tissue (spleen and liver) of KO and age-matched wildtype (WT) mice by cytology, histopathology as well as flow cytometry. No significant abnormalities were observed in KO mice of young age (6–12 weeks). NFATc2 KO mice of older age (>12 months), however, were found to be anemic, with a significant decrease in red blood cell counts as well as in hemoglobin and hematocrit values, and also showed decreased numbers of peripheral blood platelets as compared to the WT. In contrast, no significant differences between WT and KO were found in total counts of white blood cells or in leukocyte differentials. Femora of NFATc2 KO mice appeared macroscopically pale and, upon elutriation, gave yield to less than 50% of bone marrow cells compared to the WT, indicating bone marrow hypoplasia. Further analysis of bone marrow differentials by morphology and flow cytometry showed a profound decrease in erythroid cells as well as in megakaryocytes. Histopathological examination of KO bone marrow sections revealed evidence of bone marrow sclerosis, as indicated by an increase in bone trabeculae and osteoblasts within the marrow space. In some mice, an increase in reticulin fiber content was also noted. Interestingly, both liver and spleens of NFATc2 KO mice showed clear evidence for extramedullary hematopoiesis, suggesting that displacement of hematopoietic cells by the bone marrow stroma may be a possible cause of the observed cytopenias.

These results show that NFATc2 knockout mice over their lifespan develop a phenotype, which clinically resembles human osteomyelofibrosis/-sclerosis. The underlying mechanism for the observed hematopoietic abnormalities has to be defined, in particular the respective contribution of hematopoietic and bone marrow stroma cells. Given that NFAT factors are expressed at considerable levels in both hematopoietic progenitor cells and mesenchymal stem cells, our results should encourage further studies on the yet undefined role of these transcription factors within the bone marrow hematopoietic niche.
Sequential Chemotherapy Followed by High Dose Therapy and Autologous Stem Cell Rescue for Mantle Cell Lymphoma: Impact of MIB-1 on Outcome
Authors: Zelenetz Andrew D , Moskowitz Craig , Maragulia Jocelyn , Portlock Carol S. , Teruya-Feldstein Julie
Published: October 2019

Introduction: Optimal management of mantle cell lymphoma (MCL) remains undefined. However, recent data support the conclusion that upfront consolidation with high dose therapy with autologous stem cell rescue (HDT/ASCR) can improve the PFS (Dreyling, et al., 2005; Geisler, et al., 2008) and possibly OS (Geisler, et al. 2008). Based on gene expression profiling data, the proliferation signature has emerged as a critical determinant of prognosis in MCL (Rosenwald, et al., 2003). Immunohistochemical assessment of proliferation as estimated by MIB-1 (Ki-67) staining has been shown to predict outcome in patients with MCL treated with chemotherapy or immunochemotherapy. With conventional chemotherapy, the reported MIB-1 staining cutoff associated with poor prognosis reportedly varies from 10–30%. Since 1994 we have treated patients (pts) with MCL with sequential chemotherapy followed by HDT/ASCR. The current analysis is a retrospective review of our treatment program focused on the impact of upfront consolidation with HDT/ASCR on the prognostic significance of proliferation as measured by MIB-1 immunohistochemistry.

Methods: Seventy-nine patients underwent upfront consolidation with HDT/ASCR for MCL. Fifty-two patients had evaluation of proliferation by MIB-1 immunohistochemistry. MIB-1 expression was estimated visually and assigned a percentage. Patients were binned into quintiles of MIB-1 expression: 0–20% (n=32, 61.5%); 21–40% (n=5, 9.6%); 41–60% (n=5, 9.6%); 61–80% (n=5, 9.6%); and 81–100% (n=5, 9.6%). Outcomes were analyzed by the method of Kaplan-Meier and comparisons were by log-rank.

Results: The EFS and OS at 5 years was 65.1% and 61.4% respectively for the subset of patients with available MIB-1 staining (n=52); the outcomes for the entire group (n=79) did not differ from the subset. Outcomes (PFS, OS) were evaluated by MIB-1 quintile with successive cutoff values of 20%, 40%, 60% and 80%. MIB-1 cutoff values of 40% or less were not predictive of outcome. However, when the cutoff was 60% or 80%, both the PFS and OS were significantly worse for the high proliferation group. Nineteen percent of patients had a proliferation fraction of greater than 60%. For patients with MIB-1 staining of >60% the PFS was 4.2 years and was not reached for the group with staining ≤60% (p=0.004). Similarly, overall survival was significantly different, (p=0.031).

Conclusions: These findings suggest that upfront consolidation with HDT/ASCR can partially overcome the adverse impact of proliferation on outcome and the adverse outcomes are seen in a subgroup of approximately 20% of patients with MIB-1 staining of greater than 60%.
Arachidonic Acid Metabolism-Related Molecules as Candidate Markers in Subclassification of Lymphoma
Authors: Sjoberg Jan , Schain Frida , Schain Daniel , Mahshid Yilmaz , Porwit Anna , Xu Dawei , Sundstrom Christer , Claesson Hans-Erik , Bjorkholm Magnus
Published: October 2019

Arachidonic acid metabolites, like prostaglandins and leukotrienes, have been suggested to play an important role not only in inflammation but also in carcinogenesis. We have recently reported that the cysteinyl leukotriene receptor 1 (CysLT1) and 15-lipoxygenase-1 (15-LO-1), a sister enzyme to 5-LO (which is essential for leukotriene synthesis), are expressed by the malignant Hodgkin Reed-Sternberg cells of Hodgkin lymphoma (HL) and certain HL-derived cell lines, and that these cells convert arachidonic acid to the novel pro-inflammatory eoxins (Int J Cancer, 2008; FEBS J, 2008; PNAS, 2008). Given the pleiotropic effects of the CysLT1 receptor and 15-LO-1 and the fact that their expression is strictly regulated in a cell-type and tissue-specific manner, it was of interest to elucidate whether these proteins are exclusively expressed by the tumor cells of the classical HL entities. Therefore, the expression of these molecules was investigated by immunohistochemistry in a broad range of lymphomas (lymphocyte predominance (LP) HL, MALT lymphoma, T cell-derived anaplastic large cell lymphomas (ALCL), immunocytoma, mantle cell lymphoma, B-CLL, Burkitt lymphoma, follicular lymphoma, DLBCL, PTCL, primary mediastinal B cell lymphoma (PMBCL), T cell-rich B cell lymphoma; n=58). The tumor cells in one of four T cell-derived ALCLs, in contrast to all other studied non-Hodgkin lymphomas (NHLs) and LP HL tumors, strongly expressed 15-LO-1. PMBCL was the only NHL entity showing tumor cells positive for the CysLT1 receptor (9 of 10 tumors), and the PMBCL cell line Med-B1 expressed functional CysLT1 receptors, responding with a robust calcium signal upon cysteinyl leukotriene challenge. These findings further corroborate the pathologic overlap between PMBCL and classical HL. Although most cases of PMBCL are identified by routine diagnostics, the distinction between PMBCL and DLBCL may be challenging. After future careful validation in extended patient series, the CysLT1 receptor may be a potential additional marker to phenotypically distinguish these two lymphoma entities.
CD4 Cell Count of More Than 250/Microl in the Peripheral Blood Is Associated with Improved Overall Survival in Patients with Diffuse Large B-Cell Lymphoma (DLBCL) Independent of the aaIPI
Authors: Borghaei Hossein , Smith Mitchell , Millenson Michael , Li Tianyu , Shafer Danielle , Al-Saleem Tahseen I.
Published: October 2019

Background: Interaction between lymphoma and the host immune system may influence patient outcomes. The predictive value of lymphocyte subsets in the peripheral blood of patients with DLBCL on survival has not been reported. We retrospectively reviewed the flow cytometry (FCM) data of the peripheral blood in patients with DLBCL and analyzed the effect of lymphocyte subsets on overall survival from the time of FCM.

Patients and Methods: Multicolor FCM was performed on 103 patients with DLBCL treated at Fox Chase Cancer Center (during 1996–2006). All pathology specimens were centrally reviewed. About half of these patients were treated by various regimens before referral to our center. Sixty-one males and 42 females with a median age of 64 years (19–89) were studied. Absolute lymphocyte count (ALC), NK cell (CD56+CD3−), CD3+CD4+ T cell and CD3+CD8+ T cell subsets were calculated. Median overall survival (OS) from time of FCM in all evaluable patients (91) was 22 months (range: 3 to 126 months). Median cell counts were as follows: NK cells 140, CD4+= 355, CD8+=224 and the ALC= 1064. Univariate analysis was done via Kaplan-Meier estimation and multivariate analysis via Cox proportional hazard model.

Results: We found, in univariate analysis, that OS from the date of initial FCM was significantly correlated with increased CD4+ T cell count and ALC, with cutoffs of 250 and 1000 cells/microL, respectively. No significant cut-off was found for CD56+ or CD8+ cells. The hazard ratio for OS by CD4+ T cell-count is 0.240 (95% CI 0.099–0.581; p = 0.0015) and for ALC is 0.44 (95% CI: 0.217–0.905; p = 0.0256). In multivariate analysis, for patients with either lower risk aaIPI (0–1) or higher risk (2–3), the only significant predictor of OS, based on FCM data, is the CD4+ T cell-count (p =0.0098 hazard ratio 0.251, 95% CI 0.0088 to 0.716).

Conclusion: In patients with diffuse large B-cell lymphoma referred for management at a tertiary cancer center regardless of prior therapy, CD4+ T cell levels of more than 250/microl predict improved overall survival independent of the IPI.
Prognostic Significance of BCL6 Translocation in Diffuse Large B-Cell Lymphoma Patients Treated with R-CHOP
Authors: Shustik Jesse , Steidl Christian , Sehn Laurie , Gascoyne Randy D
Published: October 2019

Translocation of the BCL6 oncogene is the most commonly-detected chromosomal abnormality in diffuse large B-cell lymphoma (DLBCL), but its prognostic significance remains uncertain. BCL6 translocation has been associated with variable outcomes in prior clinical series, and its clinical impact has not been reevaluated since the introduction of rituximab (R). The objective of this study was to determine the prognostic value of BCL6 translocation in DLBCL patients treated with both CHOP and R-CHOP immunochemotherapy.

Methods We included 163 DLBCL patients treated with CHOP (n=72) or R-CHOP (n=73) at the British Columbia Cancer Agency between the years 1999–2002. Formalin-fixed paraffin-embedded diagnostic lymph node specimens were analyzed for BCL6 translocation on tissue microarray (TMA) by fluorescence in situ hybridization (FISH), using commercially available dual-color break-apart probes (Abbott Molecular, IL, USA). Immunohistochemical analysis was performed for BCL6, CD10, and MUM1 expression, and cases were categorized as germinal centre B-cell-like (GCB) or non-GCB using a standard algorithm (Hans, Blood 2004).

Results BCL6 translocation status was evaluable in 145 cases, and was positive (BCL6+) in 26% (37/145). Median age (65 vs. 59 years, p=0.03) and overall IPI score (p=0.03) were higher in the BCL6+ than in the BCL6− subgroup. Presence of BCL6 translocation correlated with non-GCB phenotype by immunohistochemical analysis (p=0.03), and showed no significant association with BCL6 protein expression (p=0.32). Median follow-up duration was 4.8 years (range, 0.1–8.4). BCL6 translocation was associated with a trend toward decreased overall survival (OS) among patients treated with R-CHOP (5-year OS 46.7% vs. 68%, p=0.098), though not among CHOP-treated patients (5-year OS 36.4% vs.49.5%, p=0.393). Kaplan-Meier analysis limited to the BCL6+ subgroup showed no overall survival difference between patients treated with CHOP and R-CHOP (p=0.67).

Conclusions BCL6 translocations are found in approximately 25% of patients with de novo DLBCL. Presence of BCL6 translocation appears to predict unfavorable outcome in DLBCL patients treated with R-CHOP. However, the adverse prognostic impact of BCL6 translocation is confounded by an association with high IPI score and with non-GCB phenotype. Prospective analysis within large clinical trials would help to determine the independent prognostic value of this marker in the rituximab era.
High-Throughput RNA Interference Screening Identifies Synthetic Lethality Between Oncogenic KRAS Dependency and Suppression of STK33
Authors: Scholl Claudia , Frohling Stefan , Dunn Ian F. , Barbie David A. , Schinzel Anna C. , Kim So Young , Silver Serena J. , Bullinger Lars , Sandy Peter , Boehm Jesse S. , Root David E. , Jacks Tyler , Hahn William C. , Gilliland D. Gary
Published: October 2019

Activating RAS mutations are among the most common pathogenetic events in a broad spectrum of hematologic malignancies and epithelial tumors. However, oncogenic RAS has thus far not proven to be a tractable target for therapeutic intervention. An alternative to direct targeting of known oncogenes is to perform “synthetic lethality” screens to identify genes that are selectively required for cell viability in the context of specific cancer-causing mutations. Using this approach, we have discovered a synthetic lethal interaction between mutant KRAS, the most frequently mutated oncogene in human cancer, and inactivation of the gene encoding the STK33 serine/threonine protein kinase. To identify genes that are essential for cell viability in the context of mutant KRAS, we performed high-throughput loss-of-function RNA interference (RNAi) screens in eight human cancer cell lines (mutant KRAS, n=4; wildtype KRAS, n=4), representing seven different tumor types (acute myeloid leukemia, multiple myeloma, colon cancer, breast cancer, ovarian cancer, prostate cancer, glioblastoma), as well as normal human fibroblasts and mammary epithelial cells. We screened each cell line with a subset of the short hairpin RNA (shRNA) library developed by the RNAi Consortium (http://www.broad.mit.edu/genome_bio/trc/rnai.html) that consists of 5,024 individual shRNA constructs targeting 1,011 human genes, including the majority of known and putative protein kinase and phosphatase genes and a selection of known cancer-related genes. In these cell lines, suppression of STK33 preferentially inhibited the viability and proliferation of cells that were dependent on mutant KRAS. The differential requirement for STK33 based on oncogenic KRAS dependency was confirmed in 16 additional cell lines using in vitro transformation assays and human tumor xenograft models. Biochemical analyses support the hypothesis that STK33 promotes cell growth and survival in a kinase activity-dependent manner by regulating the activity of S6K1 as well as BAD-induced apoptosis selectively in mutant KRAS-dependent cells. Notably, molecular genetic characterization of cancer cell lines and analysis of patient-derived genomic data sets indicate that STK33 is not frequently mutated or overexpressed in human tumors. These observations identify STK33 as a potential target for the treatment of mutant KRAS-driven cancers that may have a broad therapeutic index in normal versus malignant cells, and illustrate the potential of RNAi for discovering critical functional dependencies created by oncogenic mutations that cannot be identified using other genomic technologies.
Recruitment of the SWI/SNF Chromatin Remodeling Complex by NFATc1 in the Transcriptional Regulation of the C-MYC Oncogene in Aggressive B-Cell Lymphomas
Authors: Pham Lan V. , Tamayo Archito , Zhou Hai-Jun , Lin-Lee Yen-Chiu , Fu Lingchen , Ford Richard J.
Published: October 2019

The NFAT (nuclear factor of activated T-cells) family of transcription factors functions as integrators of multiple signaling pathways by binding to chromatin in combination with other transcription factors and coactivators to regulate genes central for cell growth and survival in hematopoietic cells. Recent experimental evidence has implicated the calcineurin/NFAT signaling pathway for involvement in the pathogenesis of various malignancies, including large B-cell lymphoma (LBCL), a non-Hodgkin’s lymphoma subgroup that is generally responsive to conventional cancer therapies (R-CHOP), but relapse is common that subsequently leads to therapeutic resistance. Although we have shown previously that NFAT family member NFATc1 is constitutively activated and has the ability to maintain cell growth and survival in LBCL cell lines and primary cells, the molecular mechanism(s) underlying how NFATc1 regulates cell growth and survival in LBCL is still unclear. In this study, we demonstrate that the well-known oncogene c-myc is transcriptionally regulated by the transcription factor NFATc1 in LBCL, through a chromatin remodeling mechanism that involves the recruitment of the SWI/SNF chromatin-remodeling complex. In aggressive B-cell lymphoma cell lines, c-myc oncogene protein expression was shown to correlate with NFATc1 protein expression. We further showed that NFATc1 binds to a specific DNA binding element within the proximal c-myc promoter and up-regulates c-myc transcription. The SWI/SNF proteins Brg-1 and Brm, chromatin-remodeling proteins that utilize ATP hydrolysis for energy to modify chromatin structure in order to regulate gene expression, also were shown to bind to the NFAT binding site on the c-myc promoter. Confocal microscopic analysis showed that NFATc1 colocalizes with Brg-1, and co-immunoprecipitation assays showed that Brg-1 interacts with NFATc1. Both proteins interact with the c-myc promoter within the NFAT binding site, as demonstrated by chromatin-immunoprecipitation (ChIP) analysis. Induction of a constitutively active mutant of NFATc1 (caNFATc1) in an NFATc1 negative lymphoma cell line induces c-myc protein expression. Constitutively active NFATc1 also enhances Brg-1 binding to the c-myc promoter when analyzed by ChIP-qPCR assays, suggesting that NFATc1 recruits Brg-1 to the NFAT binding site in the c-myc promoter. Down-regulation of NFATc1 by chemical inhibitors (FK-506) or by validated shRNA of NFATc1, inhibited c-myc protein expression and in-vitro lymphoma cell growth. Our data indicates a novel control mechanism for the transcriptional regulation of c-myc in the pathophysiology of aggressive lymphoma B cells and suggests that targeting NFATc1 could have therapeutic value.
The HMGA1a-STAT3 axis: an “Achilles Heel” for Hematopoietic Malignancies Overexpressing HMGA1a?
Authors: Resar Linda , Hillion Joelle , Dhara Surajit , Sumter Takita Felder , Mukherjee Mita , Di Cello Francescopaolo , Belton Amy , Turkson James , Jaganathan Souyma , Cheng Linzhao , Ye Zhaohui , Lin Yingwei , Aplan Peter D. , Jove Richard , Kowalski Jeanne , Wertzler Kelsey , Reeves Ray , Elbahlouh Ossama , Bhattacharya Raka
Published: October 2019

Although the high mobility group A1 (HMGA1) oncogene is widely overexpressed in high-risk hematopoietic malignancies and other aggressive cancers, the molecular mechanisms underlying transformation by HMGA1 are only beginning to emerge. The HMGA1 gene encodes the HMGA1a and HMGA1b protein isoforms, which function in regulating gene expression. We showed that HMGA1 induces leukemic transformation in cultured human lymphoid cells. Inhibiting HMGA1 expression blocks the transformed phenotype in cultured human leukemia and lymphoma cells. We also engineered HMGA1a transgenic mice and all mice develop aggressive lymphoid malignancy which closely models human T-cell acute lymphoblastic leukemia. Because HMGA1 participates in transcriptional regulation, we hypothesize that it drives leukemic transformation by dysregulating specific molecular pathways. To discover genes targeted by HMGA1 in leukemic transformation, we performed gene expression profile analysis. The signaltransducer andactivator oftranscription 3 (STAT3) gene was identified as a critical downstream target of HMGA1. STAT3 mRNA and protein are up-regulated in leukemic cells overexpressing HMGA1a and activated STAT3 recapitulates the transforming activity of HMGA1a. HMGA1a binds directly to a conserved region of the STAT3 promoter in vivo and activates transcription of the STAT3 promoter in human leukemia cells. Blocking STAT3 function with a small molecule, platinum compound inhibitor (CPA-7) induces apoptosis in leukemic cells from HMGA1 transgenic mice, but not in control cells. In primary, human leukemia samples, there is a positive correlation between HMGA1a and STAT3 mRNA. Moreover, blocking STAT3 function with a dominant-negative construct in human leukemia or lymphoma cells leads to decreased cellular motility and colony formation. We also showed that treatment with a small molecule, oligonucleotide inhibitor decreases the leukemic burden in the HMGA1a transgenic mice. Our results demonstrate that the HMGA1a-STAT3 axis is a potential “Achilles heel” that could be exploited therapeutically in selected hematopoietic malignancies.
Independent Risk Factors of Catheter-Related Thrombosis (CRT) in Adult Cancer Patients: An Individual Patient-Level Data (IPD) Meta-Analysis of Randomized Clinical Trials and Prospective Cohort Studies
Authors: Saber Wael , Moua Teng , Williams Eliot C. , Verso Melina , Agnelli Giancarlo , Couban Stephen , Young Annie , De Cicco Marcello , Biffi Roberto , van Rooden Cornelis J. , Huisman Menno V. , Fagnani Daniele , Cimminiello Claudio , Moia Marco , Povoski Stephen P. , Malak Sharp , Lee Agnes Y.
Published: October 2019

Purpose: Symptomatic catheter-related thrombosis (CRT) complicates roughly 5% of central venous catheter insertions in cancer patients. Recent studies have failed to show a reduction in CRT with routine use of pharmacologic thromboprophylaxis in all patients. We conducted a meta-analysis of individual patient-level data to identify independent, baseline risk factors of CRT that may help to select high-risk patients for prophylaxis.

Methods: PubMed, EMBASE, CINAHL, CENTRAL, DARE, Grey literature databases were searched in all languages from 1995–2008. Only prospective studies and randomized controlled trials (RCTs) were included. The primary end-point was objectively confirmed symptomatic and asymptomatic CRT. Multivariate logistic regression analysis of 17 prespecified baseline characteristics was conducted. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated.

Results: A total sample of 5636 subjects from 5 RCTs and 7 prospective studies was included in the analysis. Among these subjects, 425 CRT events were observed (8%). In multivariate logistic regression, the use of implanted ports as compared with peripherally implanted central venous catheters (PICC), decreased CRT risk (OR = 0.43; 95% CI, 0.23–0.80). Alternatively, past history of deep vein thrombosis (DVT) (OR = 2.03; 95% CI, 1.05–3.92), subclavian venipuncture insertion technique (OR = 2.16; 95% CI, 1.07–4.34), and improper catheter tip location (OR = 1.92; 95% CI, 1.22–3.02), increased CRT risk.

Conclusions: CRT risk is increased with using PICC catheters, previous history of DVT, subclavian venipuncture insertion technique and improper positioning of the catheter tip. These factors may be useful for risk stratifying patients to select those for thromboprophylaxis. Prospective studies are needed to validate these findings.
Platelets Protect Tumors from Hemorrhage Induced by Stroma-Infiltrating Leukocytes
Authors: Ho-Tin-Noe Benoit H , Carbo Carla , Demers Melanie , Cifuni Stephen M , Goerge Tobias , Wagner Denisa D.
Published: October 2019

In a recent study, we showed that platelets are crucial regulators of tumor vascular homeostasis in that they continuously prevent tumor hemorrhage through secretion of their granules. However, it remains unclear what platelets target to prevent tumor bleeding. Tumors are associated with inflammation, a cause of hemorrhage in thrombocytopenia. We hypothesized that platelets protect tumors from vascular damages induced by infiltrating inflammatory cells. Here, we report that thrombocytopenia-induced tumor hemorrhage preferentially occurs at the periphery of tumors, where massive accumulation of monocytes/macrophages and neutrophils was revealed by tumor histology. To further investigate the role of tumor-infiltrating leukocytes in the induction of tumor hemorrhage in thrombocytopenic mice, we used genetically-engineered mice with a deficiency in either beta2 or beta3 integrins, or in integrin activation. We show that these mice have decreased leukocyte infiltration in the tumor stroma and are protected from thrombocytopenia-induced tumor hemorrhage. Using a model of TNFa-induced skin inflammation, we demonstrate that releasates from collagen- and thrombin-stimulated platelets inhibit neutrophil-induced vascular damage. Our results show that platelets protect tumors from vascular leakage induced by infiltrating leukocytes and that releasate from activated platelets has potent in vivo healing properties needed after leukocyte transmigration.
Non-Redundant Roles for an Epo/EpoR/STAT5 Regulated Intracellular Serpin, Serpina-3G, during Epo- and Anemia- Induced Erythropoiesis
Authors: Dev Arvind , Fang Jing , McCrann Don , Emerson Christine , Pradeep Anamika , Browne Sarah , Ashton-Rickardt Philip , Wojchowski Don M.
Published: October 2019

Interest in advancing a more sophisticated knowledge of EPOR action mechanisms remains intense based on the emergence of novel ESAs; cytoprotective effects of EPO and ESAs in ischemically injured tissues; and adverse effects of EPO on cancer progression. By employing primary bone marrow erythroblasts and global transcriptome analyses, we recently have discovered several previously undescribed EPO/EPOR response factors that regulate erythroid progenitor cell development. These include Cyclin-G2, the pseudokinase Tribbles-3 (TRB3), and a strongly EPO-induced intracellular serpin, Serpina-3G (S3G). Here we report on EPOR- mediated routes to S3G expression, and on phenotypes resulting from S3G’s reinforced, or disrupted expression. As determined using early-stage erythroid progenitors with minimal knocked-in EPOR alleles, S3G expression proved to depend upon an EPOR-PY343/STAT5 axis. At the protein level, S3G was cytoplasmically retained (as was S3G-flag in stably transduced G1E2 cells, and in transgenic Gata1-IE3.9int-S3G mice). Ectopic expression of S3G further revealed advantaged expansion capacities. To critically assess S3G’s function, S3G knock-out mice were prepared. Consistent with a hypothesis that S3G might affect erythropoiesis selectively during anemia, BFUe, CFUe and red cell levels in S3G-null mice at steady-state were not significantly perturbed. However, S3G’s deletion markedly impaired erythropoiesis during hemolytic anemia, and inhibited EPO- induced erythropoiesis per se. In particular, hematocrits during anemia in S3G-null mice fell to 23.0 +/− 2.2% as compared to 38.7 +/− 1.8% for S3G+/+ controls. In response to EPO, an increase in hematocrit of only 1.75 +/− 0.2% was exhibited for S3G-null mice as compared to 4.9 +/− 0.5% for S3G+/+ controls. Investigations therefore establish S3G as an important non-redundant mediator of EPO- and anemia- induced erythropoiesis. They also raise interesting new questions concerning the nature of S3G’s action pathways, and S3G’s candidate pro-erythroblast intrinsic target protease.
Sequencing Acute Myeloid Leukemia Genomes with “Next Generation” Technologies.
Authors: Mardis Elaine , Ley Timothy J. , Wilson Richard K.
Published: October 2019

For most patients with a sporadic presentation of acute myeloid leukemia (AML), neither the initiating nor the progression mutations responsible for disease are known. Recent attempts to identify key mutations with directed sequencing approaches, or with array-based genomic studies, have had limited success, suggesting that unbiased whole genome sequencing approaches may be required to identify most of the mutations responsible for AML pathogenesis. Until recently, whole genome sequencing has been impractical due to the high cost of conventional capillary-based sequencing and the large numbers of enriched primary tumor cells required to yield the necessary genomic DNA for library preparation. “Next Generation” sequencing approaches have changed this landscape dramatically. Using the Solexa/Illumina platform, we have now sequenced the genomic DNA of highly enriched tumor cells and normal skin cells obtained from a carefully selected patient with a typical presentation of FAB M1 AML. We obtained 98.2 billion bases of sequences from the cytogenetically normal tumor cell genome (32.7 fold haploid coverage), and 41.8 billion bases of sequence from the normal skin genome (13.9 fold coverage). Using these data, we detected diploid sequence coverage of 91% of 46,320 heterozygous SNPs, defined in the tumor genome (by array-based genotyping), and 83% diploid coverage of the skin genome. Of 2,647,695 well-supported single nucleotide variants in the tumor genome, 2,588,486 (97.7%) were also detected in the patient’s skin genome, defining them as inherited. From the remaining variants, 8 have been fully validated as somatic mutations by conventional capillary sequencing using PCR-generated amplicons. We also detected somatic mutations in the FLT3 (ITD) and NPM1 genes (a classic NPMc mutation). Based on deep read-count data of the novel variants on a 454 sequencer, we hypothesize that all of the mutations are in virtually all of the tumor cells, and all were retained at relapse 11 months later, suggesting that a single dominant clone contained all of the mutations. None of the novel mutations has previously been detected in AML cases (and none were found in any of 187 additional AML cases studied here). A number of additional potential somatic mutations in regions lying near genes (but not altering coding sequences) are currently being validated and tested for recurrence in other AML samples. Whole genome sequencing of a second M1 AML genome is now underway. These results demonstrate the power of unbiased whole genome sequencing approaches to discover cancer-associated mutations in novel candidate genes.
Immuno-Chemotherapy with Rituximab, Methotrexate, Lomustine, and Procarbazine for the Treatment of Primary CNS Lymphoma in Patients >65 Years.
Authors: Fritsch Kristina , Kasenda Benjamin , Markert Anna , Finke Jürgen , Illerhaus Gerald
Published: October 2019

Abstract 3712

Poster Board III-648

Introduction

Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma (NHL) confined to the CNS and/or eyes at presentation. PCNSL have a poor prognosis dispite good initial response to steroids and whole brain irradiation (WBRT). Addition of high-dose methotrexate (MTX) to therapy has improved the prognosis of patients with PCNSL, resulting in median survival rates of up to 60 months (mo). However, most patients eventually relapse. Surviving patients, particularly elderly treated with combined radio-chemotherapy are at substantial risk of developing leukoencephalopathy. We developed a protocol with high-dose MTX combined with the lipophilic alkylating agents procarbacine and lomustine and the anti-CD20 monoclonal antibody rituximab (R-MPL protocol), especially adapted for elderly patients with PCNSL. Here we report the results of 28 patients treated with combined immuno-chemotherapy with R-MPL protocol within a monocentric study.

Methods

Patients ≥65 yrs with PCNSL were treated with up to 3 cycles of R-MPL protocol: rituximab (375mg/m2 d-6, 1, 15, 29), MTX (3g/m2 d2, 16, 30), procarbazine (60 mg/m2 p.o., d1-10) and lomustine (110 mg/m2 p.o., d1). Cycles were repeated d42. Inclusion criterias were age ≥65 yrs and biopsy proven PCNSL. There was no lower limit of Karnofsky Performance Score.

Results

28 patients (median age 75 yrs., range 65-83 yrs.) received R-MPL protocol. 2 patients died, one due to pulmonary embolism 2 weeks after initiation of treatment, the other had a perforation of the sigmoid and both were not evaluable for response. Objective response was seen in 25 of 26 patients (96,2%) with 19 CR and 6 PR. In 5 patients, MTX was not tolerated after 1 (n=4) and 2 (n=1) applications due to cholestatic hepatitis (n=1) and renal impairment (n=4). 2 patients with refractory disease could successfully be salvaged with AraC/thiotepa (n=1) and HDT and ASCT (n=1), respectively. 5 patients experienced relapse and could not be salvaged. After a median follow-up of 26 mo (range 2-35) 10 patients (35,7 %) are alive and disease-free. By intend-to-treat-analysis the 12-mo and 24-mo is 69% and 52% respectively. Severe leukoencephalopathy has not been observed. Most recent follow-up data will be presented in detail.

Conclusion

The immuno-chemotherapy protocol presented here is safe and shows high efficacy in treating elderly patients with PCNSL. A prospective phase-II trial will be initiated.

Disclosures:

No relevant conflicts of interest to declare.