scholarly journals STEM-09. INTRINSIC INTERFERON SIGNALING REGULATES THE CELL DEATH OF GLIOBLASTOMA STEM CELLS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii198-ii198
Author(s):  
Sabbi Khan Khan ◽  
Emmanuel Martinez-Ledesma ◽  
Sandeep Mittal ◽  
Kaitlin Gandy ◽  
Kristin Alfaro-Munoz ◽  
...  
Keyword(s):  
Cell Death ◽  
Treatment Resistance ◽  
Primary Brain Tumor ◽  
The Cancer Genome Atlas ◽  
Cytokine Signaling ◽  
Type I ◽  
Type Ii ◽  
Mechanistic Investigation ◽  
Differential Cell ◽  
Stat1 Signaling

Abstract Glioblastoma (GBM) is the most common, highly aggressive, and lethal primary brain tumor in adults. Interferon (IFN)-mediated signal transducer and activator of transcription 1 (STAT1) signaling contributes to various aspects of stemness, cell death, cytokine signaling in immune and non-immune cells. However, the role of IFN/STAT1 signaling in stemness, cell death and treatment resistance in GBM is unclear. This study aimed to investigate the cancer cell-intrinsic IFN/STAT1 signaling and its role in cell proliferation, stemness, and apoptosis. By using the metagene scores for type I and type II IFN-responsive genes, we evaluated basal IFN/STAT1 signaling in The Cancer Genome Atlas (TCGA) and in patient-derived cohorts of stem-like cells (GSCs) RNA expression datasets. In-silico analyses were further validated for the constitutive IFN signaling in a subset of GSCs using qPCR, WB and ELISA assays. We employed pharmacological activators and/or inhibitors of IFN/STAT1 signaling in GSCs to study its role in stemness and cell death. We found differential cell-intrinsic type I and type II IFN-signaling markers in GSCs and GBM tumors. High IFN-signaling is associated with mesenchymal phenotype and poor survival outcomes. Acute and chronic GSC exposure to recombinant IFNs reversibly activated both type I and II IFN-signaling in GSCs. IFN-β exposure induced apoptosis in intrinsically high IFN/STAT1-signaling GSCs, but not in the low IFN/STAT1-signaling GSCs. In summary, our findings demonstrate that GBM exhibit differential cell-intrinsic IFN-signaling, and basal IFN/STAT1 is a key factor for IFN-β-mediated cell death in GSCs. However, further mechanistic investigation of intrinsic IFN signaling in GBM, particularly in the stem cell compartment is needed.

Obinutuzumab (GA101) More Potently Engages Phagocytic-Lineage Cells Resulting In Enhanced Monocyte and Macrophage Activity When Compared To Rituximab and Ofatumumab

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5136-5136 ◽  
Author(s):  
Sylvia Herter ◽  
Christian Klein ◽  
Pablo Umana ◽  
Marina Bacac
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Nk Cell ◽  
Antibody Activity ◽  
Type I ◽  
Type Ii ◽  
Therapeutic Antibodies ◽  
Tumor Cell Death ◽  
Macrophage Activity ◽  
Anti Cd20

Abstract Therapeutic antibodies possess several clinically relevant mechanisms of action including cell death induction, perturbation of tumor cell signaling, activation of complement dependent cytotoxicity (CDC), antibody dependent cellular cytotoxicity (ADCC), antibody dependent cellular phagocytosis (ADCP) and induction of adaptive immunity. Obinutuzumab (GA101) is a novel humanized, glycoengineered Type II anti-CD20 monoclonal antibody engineered for displaying enhanced FcγRIIIa (CD16) binding affinity and characterized by stronger induction of ADCC and direct tumor cell death when compared to wild-type, Type I anti-CD20 antibodies rituximab and ofatumumab. In light of the important role of phagocytic lineage cells in the mechanism of action of therapeutic antibodies, we compared GA101, rituximab and ofatumumab for their ability to trigger FcγR-dependent monocyte and macrophage effector functions. We show that, due to glycoengineering, GA101 displays superior CD16-dependent binding to monocytes, M1 and M2c macrophages in presence of nonspecific, competing, human endogenous IgGs, a situation that more closely mimics physiological conditions. Subsequently, GA101 more strongly engages monocytes and macrophages and leads to significantly higher elimination of CD20-expressing tumor cells as shown by assays detecting total antibody activity (ADCP, ADCC and direct effects). In support of the stronger GA101 activity, higher nitric-oxide (NO) levels are also detected in supernatants of tumor/macrophage co-cultures treated with antibody. Taken together, our data show that in addition to stronger NK-cell mediated ADCC and direct cell death induction due to Type II CD20 binding, GA101 more potently engages phagocytic-lineage cells resulting in enhanced monocyte and macrophage activity under conditions that more closely resemble physiological settings. Disclosures: Herter: Roche: Employment. Klein:Roche Glycart AG: Employment. Umana:Roche: Employment, Equity Ownership. Bacac:Roche: Employment.

scholarly journals Influenza A virus antagonizes type I and type II interferon responses via SOCS1-dependent ubiquitination and degradation of JAK1

2020 ◽  
Author(s):  
Yinping Du ◽  
Fan Yang ◽  
Qiuxia Wang ◽  
Nuo Xu ◽  
Yizhang Xie ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Innate Immune ◽  
Cytokine Signaling ◽  
Type I ◽  
Type Ii ◽  
Innate Immune Responses ◽  
Suppressor Of Cytokine Signaling ◽  
Interferon Responses ◽  
Socs Protein

Abstract BACKGROUND Although influenza A virus (IAV) employs diverse strategies to evade IFN responses by inhibiting the synthesis of IFN, how IAV regulates signaling downstream of IFN is incompletely understood. METHODS In this study, we used Western blot-based protein analysis coupled with RT-qPCR, overexpression and RNA interference to investigate the regulation of JAK1 by IAV infection. RESULTS The results indicated that JAK1 was ubiquitinated and degraded, resulting in inhibition of type I and type II IFN responses, demonstrating that IAV antagonizes the IFN-activated JAK/STAT signaling pathway by inducing the degradation of JAK1. Furthermore. IAV infection upregulated the suppressor of cytokine signaling (SOCS) protein SOCS1, and SOCS1 mediated the ubiquitination and degradation of JAK1. CONCLUSION: Collectively, our findings suggest that IAV infection induced SOCS1 expression promotes JAK1 degradation, which in turn inhibits host innate immune responses.

STEM-24. INTERFERON SIGNALING REGULATES THE PROLIFERATION AND MESENCHYMAL PHENOTYPE OF GLIOBLASTOMA STEM CELLS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi26-vi26
Author(s):  
Sabbir Khan ◽  
Rajasekaran Mahalingam ◽  
Shayak Sen ◽  
Kaitlin Gandy ◽  
Kristin Alfaro-Munoz ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Single Cell ◽  
In Silico ◽  
The Cancer Genome Atlas ◽  
Cytokine Signaling ◽  
Rna Seq ◽  
Mesenchymal Phenotype ◽  
Cancer Genome Atlas ◽  
Stat1 Signaling

Abstract Interferon (IFN) signaling contributes to stemness, cell proliferation, cell death, and cytokine signaling in cancer and immune cells; however, the role of IFN signaling in glioblastoma (GBM) and GBM stem-like cells (GSCs) is unclear. This study aimed to investigate the cancer cell-intrinsic IFN signaling in tumorigenesis and malignant phenotype of GBM. We characterized cell-intrinsic IFN signaling in The Cancer Genome Atlas, patient-derived cohorts of GSCs, and published single-cell RNA sequencing datasets by in-silico analyses. The in-silico findings were further validated by evaluating the cytokine secretion and using pharmacological activators and blockers of IFN/transducer and activator of transcription 1 (STAT1) signaling. We found that GSCs and GBM tumors exhibited differential cell-intrinsic IFN signaling, and high IFN/STAT1 signaling is associated with mesenchymal phenotype and poor survival outcomes. Ruxolitinib, a pharmacological inhibitor of IFN/STAT1, abolished the IFN/STAT1 signaling in GSCs with intrinsically high IFN signaling. IFN-γ treatment for 1 week promotes the mesenchymal phenotype in GSCs with low IFN signature. In addition, chronic inhibition of IFN/STAT1 signaling with ruxolitinib decreased cell proliferation and mesenchymal signatures (CD44, YKL40, and TIMP1) in GSCs with intrinsically active IFN/STAT1 signaling. Publicly available human glioma single-cell RNA-seq (scRNA-seq) datasets analyses showed that both tumor and nontumor cells expressed IFN signaling genes, and the mesenchymal signature was highly expressed in the same cluster where IFN signaling genes were upregulated. We demonstrated that cell-intrinsic IFN signaling in GSCs and GBM tumors is associated with mesenchymal signatures and cell proliferation. Our study provides evidence for the possibility of targeting IFN signaling in a specific group of GBM patients.

Superior Efficacy of the Novel Type II, Glycoengineered CD20 Antibody GA101vs. the Type I CD20 Antibodies Rituximab and Ofatumumab

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3925-3925 ◽  
Author(s):  
Sylvia Herter ◽  
Inja Waldhauer ◽  
Tina Otz ◽  
Frank Herting ◽  
Sabine Lang ◽  
...  
Keyword(s):  
Cell Death ◽  
Type I ◽  
Type Ii ◽  
B Cell Depletion ◽  
Employment Equity ◽  
Direct Cell ◽  
Equity Ownership ◽  
Cd20 Antibody ◽  
Dose Dependent ◽  
Cd20 Antibodies

Abstract Abstract 3925 GA101 is Type II, glycoengineered CD20 monoclonal antibody currently in PhII/III clinical trials. We have previously shown that GA101 mediates superior in vitro and in vivo activity compared to the Type I CD20 antibody rituximab. By epitope mapping and crystallography we have shown that GA101 recognizes CD20 in a unique way that is different from Type I CD20 antibodies and have proposed that this may be the basis for the Type II character of GA101. Here we compare for the first time GA101 with rituximab, the standard of care in various clinical settings in NHL and B-CLL in combination with chemotherapy, as well as with the Type I CD20 antibody ofatumumab, which was recently approved for treatment of B-CLL patients refractory to fludarabine and alemtuzumab. The following assays were used to compare the three anti-CD20 antibodies: i) Binding to NHL cell lines Z138 (MCL, ca. 60.000 CD20 binding sites per cell) and SU-DHL4 (DLBCL, ca. 1 Mio CD20 binding sites per cell) assessed by FACS, ii) Cell death induction, detected by AxV/PI staining and FACS, on a panel of NHL cell lines, iii) Antibody dependent cellular cytotoxicity mediated by PBMNCs as effector and Z138, SU-DHL4 as target cells (ADCC, LDH release assay); iv) Complement dependent cytotoxicity with Z138, SU-DHL4 as target cells (CDC, LDH release assay) and v) B-cell depletion (assessed by FACS) in whole blood from healthy donors. Dose-dependent anti-tumoral activity was assessed in a s.c. SU-DHL4 NHL xenograft model in Scid beige mice. Survival experiments in a disseminated Z138 MCL model are ongoing and an update on the results will be included as part of the poster presentation. Ofatumumab (“Arzerra”) was purchased from a local pharmacy, GA101 and rituximab were obtained from Hoffmann La Roche AG, Basel. First, binding studies confirmed that GA101 shows half-maximal binding to NHL cells relative to rituximab and ofatumumab, a known property of Type II CD20 antibodies. EC50 values of binding were comparable indicating that GA101, rituximab and ofatumumab have apparent binding affinities in the low nanomolar range on NHL cells independent of the level of CD20 expression. Second, the three CD20 antibodies were compared for their induction of direct cell death as measured by AxV/PI staining. Overall, GA101 mediated superior direct cell death induction compared to rituximab and ofatumumab utilizing a panel of NHL cell lines of different origins. Immune effector-related mechanisms of action were subsequently compared by ADCC and CDC assays. GA101, a glycoengineered antibody with enhanced affinity for FcgRIIIa, was found to exhibit up to 100-fold higher ADCC potency than rituximab and ofatumumab on Z138 and SU-DHL4 cells. CDC, as expected for a Type II CD20 antibody was ca. 10 to 1,000 less potent compared to the Type I antibodies rituximab and ofatumumab. In order to integrate the different mechanisms of action (direct cell death, ADCC, CDC), autologous ex vivo B-cell depletion assays with whole blood from healthy donors containing natural immune effector cells, human complement and physiological concentrations of human immunoglobulins were performed. These studies showed that GA101 was more potent in terms of EC50 values and more efficacious in terms of absolute B-cell depletion when compared to rituximab and ofatumumab. Finally, the dose-dependent effects of the three CD20 antibodies was studied on the growth of s.c. SU-DHL4 DLBCL xenografts in SCID beige mice. GA101 induced a dose-dependent anti-tumoral effect including complete tumor remission and was superior to the Type I antibodies rituximab and ofatumumab at saturating antibody doses. In summary, the preclinical data presented herein demonstrate that the Type II, glycoengineered CD20 antibody GA101 is differentiated from the Type I CD20 antibodies rituximab and ofatumumab by its superior overall activity supporting its further clinical investigation. Of note, in contrast to previous publications, in this series of assays no superior preclinical activity of ofatumumab was observed when compared to rituximab. Disclosures: Herter: Roche: Employment, Patents & Royalties. Waldhauer:Roche: Employment. Otz:Roche: Employment. Herting:Roche: Employment, Patents & Royalties. Lang:Roche: Employment. Nicolini:Roche: Employment. Römmele:Roche: Employment. Friess:Roche: Employment, Patents & Royalties. Van Puijenbroek:Roche: Employment. Bacac:Roche: Employment. Weidner:Roche: Employment, Equity Ownership. Gerdes:Roche: Employment, Equity Ownership, Patents & Royalties. Umana:Roche: Employment, Equity Ownership, Patents & Royalties. Klein:Roche: Employment, Equity Ownership, Patents & Royalties.

Dual Targeting of JAK2 Signaling with a Type II JAK2 Inhibitor and of mTOR with a TOR Kinase Inhibitor Induces Apoptosis in CRLF2-Rearranged Ph-like Acute Lymphoblastic Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3706-3706 ◽  
Author(s):  
Ce Shi ◽  
Lina Han ◽  
Yoko Tabe ◽  
Hong Mu ◽  
Shuo-Chieh Wu ◽  
...  
Keyword(s):  
Cell Death ◽  
Intracellular Signaling ◽  
Kinase Inhibitor ◽  
Apoptotic Cell ◽  
Lymphoblastic Leukemia ◽  
Mtor Inhibitors ◽  
Type I ◽  
Type Ii ◽  
Jak2 Inhibitor

Abstract Philadelphia chromosome-like acute lymphoblastic leukemia (“Ph-like ALL”) is a subtype of high-risk B-precursor ALL (B-ALL) that carries a high risk of relapse after conventional chemotherapy (Mullighan et al, N Engl J Med. 2009). Rearrangements in CRLF2, leading to overexpression of the receptor for the cytokine thymic stromal lymphopoietin (TSLP), are present in approximately 50% of Ph-like ALLs and are associated with hyperactive JAK/STAT and PI3K/mTOR signaling (Harvey et al, Blood 2010; Tasian et al, Blood 2014). Previous studies established that combining a tyrosine kinase inhibitor (TKI) with an mTOR inhibitor provides greater anti-leukemia efficacy than a TKI alone in Ph+ B-ALL (Janes et al, Nat. Med. 2013). While allosteric mTOR inhibitors such as rapamycin only partially block mTORC1 and do not directly inhibit mTORC2, second-generation ATP-competitive mTOR kinase inhibitors (TOR-KIs) efficiently block both mTOR outputs and show greater efficacy when combined with TKIs. In this study, we investigated anti-leukemia efficacy and intracellular signaling networks in Ph-like CRLF2+ ALL models treated with combinations of a type I or type II JAK-2 inhibitor and a TOR-KI. The inhibitors were tested in human B-precursor Ph-like ALL cell lines MUTZ5 (IGH@-CRLF2 translocation, JAK2 R683G mutation) and MHH-CALL-4 (IGH@-CRLF2 translocation, JAK2 I682F mutation), B-ALL cell line REH (CRLF2wt), and primary CRLF2+ xenograft cells in vitro. For signaling and growth inhibition studies, cells were stimulated with 25 ng IL-7 or TSLP for 30 min, then with JAK2 type I inhibitor ruxolitinib (500nM) or type II inhibitor NVP-BBT594 (500nM) (Andraos et al., Cancer Discov. 2012) and allosteric mTOR inhibitor rapamycin or TOR-KI AZD2014. Effects on intracellular signaling were determined by phospho-flow cytometry. Anti-leukemia effects were characterized by viable cell counts and annexin V flow cytometry. In vitro stimulation of CRLF2-rearranged cells with TSLP robustly induced JAK/STAT signaling (p-JAK2(Tyr1008), p-STAT5(Ty694)) and AKT/pS6 signaling (p-AKT(Ser473), p-rS6(S235/236) (Fig. 1A). Stimulation with IL-7, mimicking support by the normal bone marrow environment, induced a lesser degree of activation of these phospho-proteins, except for p-4EBP1(T37/46), which was constitutively highly expressed in these cells and further induced by IL-7. These findings warranted combination studies of JAK2 and mTOR inhibitors. JAK2 inhibition with ruxolitinib or BBT594 efficiently inhibited TLSP-induced STAT5, AKT, and S6 activation, yet failed to decrease p-4EBP1 (Fig. 1A). AZD2014 but not rapamycin fully inhibited p-4EBP1, consistent with efficient inhibition of TORC1, and caused profound cell cycle arrest and growth arrest in CRLF2+ cells (Fig. 1A, C). In turn, combination of ruxolitinib and AZD2014 further reduced cell proliferation but did not induce apoptotic cell death (Fig. 1B, D). Recent studies indicate persistence of JAK2-mutated cells in myeloproliferative neoplasms upon long-term exposure to a type I JAK2 inhibitor, mediated by JAK2 heterodimerization and reactivation of JAK-STAT signaling (Koppikar et al., Nature 2012). We therefore compared the in vitro efficacy of ruxolitinib and BBT594, a type II JAK2 inhibitor that retains the ability to bind inactive JAK2, in Ph-like ALL cells. In MUTZ-5 but not in MHH-CALL-4 cells, ruxolitinib increased JAK2 activation loop phosphorylation (p-JAK2-Tyr1008) despite suppression of STAT5 phosphorylation; in contrast, BBT594 diminished both p-JAK2 and p-STAT5. Unexpectedly, BBT594 induced apoptotic cell death in both MUTZ5, MHH-CALL-4 (Fig 1B) and in ALL blasts recovered from primary CRLF2+ xenograft and grown in OP9 in vitro co-culture; the combination of BBT594 with AZD2014 increased apoptosis and reduced cell viability even further, in both cell lines and in stroma-attached primary ALL cells. In summary, these results suggest that efficient blockade of JAK2/STAT5 with a type II JAK2 inhibitor translates into cell death of JAK2-addicted CRLF2-rearranged cells and may have the capacity to eliminate JAK2-mutated clones. Concomitant blockade of TORC1 signaling with a TOR-KI reduces B-ALL cell proliferation through potent inhibition of 4EBP1 and causes synthetic lethality, providing avenues for novel, rationally designed combinatorial regimens in this subset of Ph-like B-ALL. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Combined Targeting of JAK2 with a Type II JAK2 Inhibitor and mTOR with a TOR Kinase Inhibitor Constitutes Synthetic Activity in JAK2-Driven Ph-like Acute Lymphoblastic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2529-2529 ◽  
Author(s):  
Ce Shi ◽  
Lina Han ◽  
Qi Zhang ◽  
Kathryn G. Roberts ◽  
Eugene Park ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Intracellular Signaling ◽  
Research Funding ◽  
Apoptotic Cell ◽  
Lymphoblastic Leukemia ◽  
Synthetic Activity ◽  
Type I ◽  
Type Ii ◽  
Jak2 Inhibitors

Abstract Background and rationale: Philadelphia chromosome-like acute lymphoblastic leukemia ("Ph-like ALL") is a subtype of high-risk B-precursor ALL (B-ALL), which carries a high risk of relapse with conventional chemotherapy(Roberts et al, N Engl J Med. 2014). Rearrangements in CRLF2, leading to overexpression of cytokine receptor for thymic stromal lymphopoietin (TSLP), are present in approximately 50% of Ph-like ALL and are associated with hyperactive JAK/STAT and PI3K/mTOR signaling (Harvey et al, Blood 2010;Tasian et al, Blood 2014).In addition,JAK2 fusion proteins, such as PAX5-JAK2 represent a novel class of JAK2-driven cellular transformation in B-ALL (Dagmar et al, Blood 2015). Our prior studies in Ph+ B-ALL established that combining tyrosine kinase inhibitors (TKIs) with second generation ATP-competitive mTOR kinase inhibitors (TOR-KIs) provides greater anti-leukemia efficacy compared to TKIs in Ph+ ALL (Janeset al, Nat. Med. 2013). In this study, we investigated anti-leukemia efficacy and intracellular signaling networks upon combination of type I or type II JAK2 inhibitors and TOR-KIs in JAK2-driven Ph-like ALL models. Methods. The human B-precursor Ph-like ALL cell lines MUTZ5 (which harborsIGH-CRLF2 translocation and JAK2 R683G mutation), MHH-CALL-4 (IGH-CRLF2 translocation and JAK2 I682F),Reh (ETV6-RUNX1 B-precursor ALL cell line)and mouse Arf-null PAX5-JAK2-MIG + IK6-MIR(IL7-dependent primary Arf-/- pre-B cells expressing the dominant negative Ikaros isoform IK6 with PAX5-JAK2 fusion protein) were studied. Signal transduction inhibitors (STIs): JAK2 type I inhibitor ruxolitinib and type II inhibitor NVP-BBT594 (Andraos et al., Cancer Discovery 2012); allosteric mTOR inhibitor rapamycin or mTOR-KI AZD2014. Effects on intracellular signaling were determined using phospho-flow cytometry and Westernblot analysis. Anti-leukemia effects were quantified using CellTiter-Glo viability assay and annexin V flow cytometry. Results. In vitro stimulation of CRLF2-rearranged cells with TSLP robustly induced JAK/STAT signaling (Fig 1D). JAK2 inhibition with ruxolitinib or BBT594 efficiently inhibited TLSP-induced STAT5, AKT, ERK and S6 activation, yet failed to affect4E-BP1 activation. The TOR-KI AZD2014 but not rapamycin fully inhibited phosphorylation of 4E-BP1, consistent with efficient inhibition of TORC1, and caused profound cell cycle arrest and growth inhibition of Ph-like cells. Combination of ruxolitinib and AZD2014 further inhibited cell proliferation, yet did not induce apoptotic cell death. Recent studies indicate persistence of JAK2-mutated cells upon chronic exposure to type I JAK2 inhibitors, through an adaptive resistance mechanism involving JAK2 heterodimerization and reactivation of JAK-STAT signaling (Koppikar et al., Nature 2012). We therefore compared the in vitro efficacy of ruxolitinib and BBT594, a type II JAK2 inhibitor that retains the ability to bind inactive JAK2 in Ph-like ALL cells. In MUTZ-5 but not in MHH-CALL-4 cells, ruxolitinib increased JAK2 activation loop phosphorylation (p-JAK2-Tyr1008) despite suppression of p-STAT5; in contrast, BBT594 diminished bothp-JAK2 and p-STAT5 in both cell lines. Unexpectedly, BBT594 induced apoptotic cell death in all JAK2-driven Ph-like ALL cell lines MUTZ5, MHH-CALL-4 and Arf-null PAX5-JAK2+IK6, but not in REH cells. Combination of BBT594 with AZD2014 further inhibited phosphorylation of JAK2, AKT, 4E-BP1 and eIF4E, and synergistically induced apoptosis and reduced cell viability in Ph-like ALL cell lines(combination index: MUTZ5, 0.71; MHH-CALL-4, 0.57; Arf-nullPAX5-JAK2+ IK6, 0.81). Of importance, BBT594 and AZD2014 combination induced apoptosis in five JAK2-mutant Ph-like ALL xenograft primary samples. In summary, these results suggest that efficient blockade of JAK2/STAT5 with type II JAK2 inhibitors translates into cell death of mutant JAK2-driven Ph-like ALL cells. Furthermore, concomitant blockade of TORC1 signaling with TOR-KI reduces B-ALL cell proliferation through potent inhibition of 4E-BP1 and causes synthetic activity, providing avenues for novel rationally designed combinatorial regimens in this subset of Ph-like B-ALL. The in vivo studies to test these hypotheses are ongoing using patient-derived xenografts. Disclosures Jabbour: Pfizer: Consultancy, Research Funding. Tasian:Incyte: Consultancy; Gilead: Research Funding. Mullighan:Amgen: Honoraria, Speakers Bureau; Cancer Science Institute: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Honoraria; Loxo Oncology: Research Funding. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

scholarly journals Influence of Polymer Charge on the Localization and Dark- and Photo-Induced Toxicity of a Potential Type I Photosensitizer in Cancer Cell Models

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1127 ◽  
Author(s):  
Mikael Lindgren ◽  
Odrun A. Gederaas ◽  
Monica Siksjø ◽  
Tom A. Hansen ◽  
Lena Chen ◽  
...  
Keyword(s):  
Cell Death ◽  
Singlet Oxygen ◽  
Deuterium Oxide ◽  
Current Trend ◽  
Chinese Hamster ◽  
Type I ◽  
Type Ii ◽  
Molecular Systems ◽  
Cell Compartments ◽  
Survival Studies

A current trend within photo-dynamic therapy (PDT) is the development of molecular systems targeting hypoxic tumors. Thus, type I PDT sensitizers could here overcome traditional type II molecular systems that rely on the photo-initiated production of toxic singlet oxygen. Here, we investigate the cell localization properties and toxicity of two polymeric anthracene-based fluorescent probes (neutral Ant-PHEA and cationic Ant-PIm). The cell death and DNA damage of Chinese hamster ovary cancer cells (CHO-K1) were characterized as combining PDT, cell survival studies (MTT-assay), and comet assay. Confocal microscopy was utilized on samples incubated together with either DRAQ5, Lyso Tracker Red, or Mito Tracker Deep Red in order to map the localization of the sensitizer into the nucleus and other cell compartments. While Ant-PHEA did not cause significant damage to the cell, Ant-PIm showed increased cell death upon illumination, at the cost of a significant dark toxicity. Both anthracene chromophores localized in cell compartments of the cytosol. Ant-PIm showed a markedly improved selectivity toward lysosomes and mitochondria, two important biological compartments for the cell’s survival. None of the two anthracene chromophores showed singlet oxygen formation upon excitation in solvents such as deuterium oxide or methanol. Conclusively, the significant photo-induced cell death that could be observed with Ant-PIm suggests a possible type I PDT mechanism rather than the usual type II mechanism.

scholarly journals Two Survivor Pathways That Allow Growth in the Absence of Telomerase Are Generated by Distinct Telomere Recombination Events

2001 ◽  
Vol 21 (5) ◽  
pp. 1819-1827 ◽  
Author(s):  
Qijun Chen ◽  
Arne Ijpma ◽  
Carol W. Greider
Keyword(s):  
Cell Death ◽  
Yeast Cells ◽  
Type I ◽  
Telomerase Rna ◽  
Type Ii ◽  
Triple Mutant ◽  
Telomere Elongation

ABSTRACT Yeast cells can survive in the absence of telomerase RNA,TLC1, by recombination-mediated telomere elongation. Two types of survivors, type I and type II, can be distinguished by their characteristic telomere patterns. RAD52 is essential for the generation of both types of survivors. Deletion of bothRAD50 and RAD51 produces a phenotype similar to that produced by deletion of RAD52. Here we examined the effects of the RAD50 and the RAD51 epistasis groups as well as the RAD52 homologue, RAD59, on the types of survivors generated in the absence of telomerase.rad59 mutations completely abolished the ability to generate type II survivors, while rad50 mutations decreased the growth viability of type II survivors but did not completely eliminate their appearance. Mutations in RAD51, RAD54, andRAD57 had the converse affect: they eliminated the ability of cells to generate type I survivors in a tlc1 strain. The triple mutant, tlc1 rad51 rad59, was not able to generate survivors. Thus either type I or type II recombination pathways can allow cells to survive in the absence of telomerase; however, elimination of both pathways in a telomerase mutant leads to the inability to elongate telomeres and ultimately cell death.

scholarly journals Novel type II anti-CD20 monoclonal antibody (GA101) evokes homotypic adhesion and actin-dependent, lysosome-mediated cell death in B-cell malignancies

Blood ◽  
2011 ◽  
Vol 117 (17) ◽  
pp. 4519-4529 ◽  
Author(s):  
Waleed Alduaij ◽  
Andrei Ivanov ◽  
Jamie Honeychurch ◽  
Eleanor J. Cheadle ◽  
Sandeep Potluri ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Actin Polymerization ◽  
Type I ◽  
Type Ii ◽  
B Cell Malignancies ◽  
Therapeutic Success ◽  
Wide Range ◽  
Anti Cd20

Abstract The anti-CD20 mAb rituximab has substantially improved the clinical outcome of patients with a wide range of B-cell malignancies. However, many patients relapse or fail to respond to rituximab, and thus there is intense investigation into the development of novel anti-CD20 mAbs with improved therapeutic efficacy. Although Fc-FcγR interactions appear to underlie much of the therapeutic success with rituximab, certain type II anti-CD20 mAbs efficiently induce programmed cell death (PCD), whereas rituximab-like type I anti-CD20 mAbs do not. Here, we show that the humanized, glycoengineered anti-CD20 mAb GA101 and derivatives harboring non-glycoengineered Fc regions are type II mAb that trigger nonapoptotic PCD in a range of B-lymphoma cell lines and primary B-cell malignancies. We demonstrate that GA101-induced cell death is dependent on actin reorganization, can be abrogated by inhibitors of actin polymerization, and is independent of BCL-2 overexpression and caspase activation. GA101-induced PCD is executed by lysosomes which disperse their contents into the cytoplasm and surrounding environment. Taken together, these findings reveal that GA101 is able to potently elicit actin-dependent, lysosomal cell death, which may potentially lead to improved clearance of B-cell malignancies in vivo.

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