Correlation of methylthioadenosine phosphorylase (MTAP) loss with response to anti-folate therapy in urothelial bladder carcinoma (UBC).

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 4521-4521
Author(s):  
Omar Alhalabi ◽  
Jianfeng Chen ◽  
Matthew T Campbell ◽  
Rebecca Slack Tidwell ◽  
Guangchun Han ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Retrospective Analysis ◽  
Cell Lines ◽  
De Novo ◽  
Synthetic Lethality ◽  
In Vivo Studies ◽  
Protein Loss ◽  
Open Label ◽  
Nucleotide Synthesis

4521 Background: The MTAP gene encodes an essential enzyme for the salvage pathway of nucleotide synthesis and is frequently deleted in UBC. Anti-folate agents such as pemetrexed can effectively inhibit the de novo pathway of nucleotide synthesis and as a result, create a synthetic lethality in MTAP deficient UBC. We hypothesize that MTAP gene loss correlates with enhanced response to pemetrexed in UBC. Methods: We investigated MTAP gene deletion rates in the TCGA database and determined MTAP protein loss rates by immunohistochemistry (IHC) using a UBC tissue microarray (TMA) from 151 patients (pts). We then performed in vitro and in vivo studies using MTAP proficient and MTAP deficient bladder cancer cell lines. At the clinical level, we performed a retrospective analysis based on MTAP status of pts treated with pemetrexed as 2nd line at our institution between 2014 and 2018. We are now enrolling pts in a single-arm, open-label, phase II clinical trial (NCT02693717) with pemetrexed in pts with MTAP deficient UBC. Results: Per our TCGA and TMA IHC analyses, MTAP deficiency rate was 25.9% and 27.8%, respectively. MTAP deficient UBC cell lines were at least 40 times more sensitive to pemetrexed than MTAP proficient lines. Knockdown of the MTAP gene increased apoptosis rate by pemetrexed from approximately 20% to 60%. Additionally, pemetrexed significantly inhibited the growth of MTAP deficient or knockdown xenograft tumors but not MTAP proficient tumors. Retrospective analysis of 12 pts using RECIST criteria indicated that all 4 MTAP deficient UBC pts responded to pemetrexed whereas only 1 of 8 (12.5%) MTAP proficient UBC pts responded. Of the 6 pts enrolled on the clinical trial, 3 (50%) had complete or partial response, 1 had stable disease, 1 was not evaluable and 1 had disease progression. Combined analysis of the entire experience demonstrates a higher response rate in MTAP deficient UBC (70%) as compared to MTAP proficient UBC (12.5%). Conclusions: Our preclinical and clinical data demonstrate that MTAP loss in UBC leads to a state of synthetic lethality when treated with pemetrexed and should be further investigated as a novel biomarker to predict response to anti-folate agents.

scholarly journals A Novel FBXO45-Gef-H1 Axis Controls Oncogenic Signaling in B-Cell Lymphoma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 711-711
Author(s):  
Anagh Anant Sahasrabuddhe ◽  
Xiaofei Chen ◽  
Kaiyu Ma ◽  
Rui Wu ◽  
Richa Kapoor ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Germinal Center ◽  
De Novo ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
In Vivo Studies

Abstract Introduction: Diffuse large B cell lymphoma (DLBCL) is the most common form of malignant lymphoma and may arise de novo, or through transformation from a pre-existing low-grade B cell lymphoma such as follicular lymphoma (FL). However, the post-translational mechanisms and deregulated pathways underlying the pathogenesis of disease evolution are not fully understood. Methods: We employed integrated functional and structural genomics and mass spectrometry (MS)-driven proteomics which implicated a possible novel tumor suppressor role for a conserved E3 ubiquitin ligase FBXO45 in DLBCL pathogenesis. We generated conditional knockout mice targeting loss of Fbxo45 in germinal center (GC) B-cells using the Cg1-Cre-loxP system and an assortment of CRISPR-mediated knockouts of FBXO45 in B cell lymphoma cells (FL518, BJAB, U2932). We engineered B cell lines (BJAB, U2932) to inducibly express FLAG-tagged FBXO45 to identify candidate substrates of FBXO45 using liquid chromatography-tandem MS. In vitro biochemical and in vivo studies using a variety of genetically-modified lines in xenograft studies in immunodeficient mice were performed to validate observations from proteogenomic studies. Whole genome sequencing (WGS) and genomic copy number studies were interrogated to investigate structural alterations targeting FBXO45 in primary human lymphoma samples. Results: Conditional targeting of Fbxo45 in GCB-cells in transgenic mice resulted in abnormal germinal center formation with increased number and size of germinal centers. Strikingly, targeted deletion of Fbxo45 in GCB-cells resulted in spontaneous B cell lymphomas with (22/22);100%) penetrance and none of the wild-type (WT) littermates (0/20; 0%) developed lymphoma at 24 months. Macroscopic examination revealed large tumor masses, splenomegaly, and lymphadenopathy at different anatomic locations including ileocecal junction, mesenteric, retroperitoneal and cervical lymph nodes and thymus. Next generation sequencing of immunoglobulin heavy chain genes revealed monoclonal or oligoclonal B cell populations. Using proteomic analysis of affinity-purified FBXO45-immunocomplexes and differential whole proteome analysis from GCB-cells of Fbxo45 wt/wt vs Fbxo45 fl/fl mice, we discovered that FBXO45 targets the RHO guanine exchange factor GEF-H1 for ubiquitin-mediated proteasomal degradation. FBXO45 exclusively interacts with GEF H1 among 8 F-box proteins investigated and silencing of FBXO45 using three independent shRNA and CRISPR-Cas9-mediated knockouts in B-cell lymphoma cell lines promotes RHOA and MAPK activation, B cell growth and enhances proliferation. GEF-H1 is stabilized by FBXO45 depletion and GEF-H1 ubiquitination by FBXO45 requires phosphorylation of GEF-H1. Importantly, FBXO45 depletion and expression of a GEF-H1 mutant that is unable to bind FBXO45 results in GEF-H1 stabilization, promotes hyperactivated RHO and MAPK signaling and B-cell oncogenicity in vitro and in vivo. Notably, this phenotype is reverted by co-silencing of GEF-H1. Inducible ectopic expression of FBXO45 triggers accelerated turnover of GEF H1 and decreased RHOA signaling. Genomic analyses revealed recurrent loss targeting FBXO45 in transformed DLBCL (25%), de novo DLBCL (6.6%) and FL (2.3%). In keeping with our observation of prolonged hyperactivation of pERK1/2 consequent to FBXO45 ablation, in vitro and in vivo studies using B-cell lymphoma cell lines and xenografts demonstrated increased sensitivity to pharmacologic blockade with the MAP2K1/2 (ERK1/2) inhibitor Trametinib. Conclusions: Our findings define a novel FBXO45-GEF-H1-MAPK signalling axis, which plays an important role in DLBCL pathogenesis. Our studies carry implications for potential exploitation of this pathway for targeted therapies. Disclosures Siebert: AstraZeneca: Speakers Bureau. Lim: EUSA Pharma: Honoraria.

scholarly journals DDRE-29. DE NOVO PYRIMIDINE SYNTHESIS IS A TARGETABLE VULNERABILITY IN IDH-MUTANT GLIOMA

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. i12-i13
Author(s):  
Diana D Shi ◽  
Adam C Wang ◽  
Michael M Levitt ◽  
Jennifer E Endress ◽  
Min Xu ◽  
...  
Keyword(s):  
Cell Lines ◽  
De Novo ◽  
Synthetic Lethality ◽  
Nucleotide Metabolism ◽  
Metabolic Inhibitor ◽  
Lower Grade ◽  
Nucleotide Synthesis ◽  
Pyrimidine Synthesis ◽  
Pyrimidine Nucleotide ◽  
Idh1 Mutations

Abstract 70–90% of lower-grade gliomas and secondary glioblastomas harbor gain-of-function mutations in isocitrate dehydrogenase 1 (IDH1), causing overproduction of the oncometabolite (R)-2-hydroxyglutarate [(R)-2HG]. Although inhibitors of mutant IDH enzymes are effective in other cancers, including leukemia, they have shown guarded efficacy in preclinical and clinical brain tumor studies, thus underscoring the need to identify additional therapeutic targets in IDH mutant glioma. We sought to identify tumor-specific metabolic vulnerabilities induced by IDH1 mutations that could be exploited therapeutically. To uncover such vulnerabilities, we conducted a chemical synthetic lethality screen using isogenic IDH1 mutant and IDH1 wild-type (WT) glioma cell lines and a novel metabolic inhibitor screening platform. We discovered that IDH1 mutant cells are hypersensitive to drugs targeting enzymes in the de novo pyrimidine nucleotide synthesis pathway, including dihydroorotate dehydrogenase (DHODH). This vulnerability is specific because inhibitors of purine nucleotide metabolism did not score in our screen. We validated that the cytotoxicity of pyrimidine synthesis inhibitors is on-target and showed that IDH1 mutant patient-derived glioma stem-like cell lines are also hyperdependent on de novo pyrimidine nucleotide synthesis compared to IDH1 WT lines. To test pyrimidine synthesis dependence of IDH1 mutant gliomas in vivo, we used a brain-penetrent DHODH inhibitor currently undergoing evaluation in leukemia patients, BAY 2402234. We found that BAY 2402234 displays monotherapy activity against gliomas in an orthotopic xenograft model of IDH1 mutant glioma, with an effect size that compared favorably with radiotherapy. We also developed novel genetically engineered and allograft mouse models of mutant IDH1-driven anaplastic astrocytoma and showed that BAY 2402234 blocked growth of orthotopic astrocytoma allografts. Our findings bolster rationale to target DHODH in glioma, highlight BAY 2402234 as a clinical-stage drug that can be used to inhibit DHODH in brain tumors, and establish IDH1 mutations as predictive biomarkers of DHODH inhibitor efficacy.

scholarly journals RARE-22. THERAPEUTIC TARGETING OF PURINE METABOLISM IN DIPG

2021 ◽  
Vol 23 (Supplement_1) ◽  
pp. i45-i45
Author(s):  
Ian Mersich ◽  
Biplab Dasgupta
Keyword(s):  
Cell Lines ◽  
De Novo ◽  
Treatment Strategies ◽  
Diffuse Intrinsic Pontine Glioma ◽  
Purine Metabolism ◽  
In Vivo Studies ◽  
Molecule Inhibitor ◽  
Clinical Benefits

Abstract Diffuse intrinsic pontine glioma is a universally lethal disease primarily impacting pediatric patients. There are currently no targeted therapies increasing overall for patients with these tumors; therefore, our lab set out to elucidate metabolic dependencies in DIPG patient-derived cell lines with the ultimate goal of identifying novel therapeutic targets. Through untargeted metabolomics and gene expression analyses, we have identified the purine metabolism gene ATIC to be important for DIPG tumor cell survival and proliferation. Anti-folate drugs such as methotrexate target de novo purine biosynthesis and are used to treat other pediatric cancers; however, we have identified a small molecule inhibitor of ATIC that may offer clinical benefits over other inhibitors of this pathway. In vitro cell viability experiments have demonstrated DIPG cell lines are much more sensitive to the ATIC inhibitor relative to normal neural stem cells and glial cell lines. Furthermore, we have started in vivo studies on pre-clinical mouse models of DIPG with promising results. Treatment with the ATIC inhibitor has significantly increased overall survival relative to control and vehicle treated mice. The dosage we started at was well tolerated in these mice so we are following up on this in vivo work through dose-escalation studies as well as combination treatment strategies. Mechanistically, the ATIC inhibitor works differently than anti-folate compounds such as methotrexate; therefore we are also elucidating why cancer cells are much more sensitive to this compound.

scholarly journals Direct antivirals working against the novel coronavirus: azithromycin (DAWn-AZITHRO), a randomized, multicenter, open-label, adaptive, proof-of-concept clinical trial of new antivirals working against SARS-CoV-2—azithromycin trial

Trials ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Iwein Gyselinck ◽  
◽  
Laurens Liesenborghs ◽  
Ewout Landeloos ◽  
Ann Belmans ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Standard Of Care ◽  
Ordinal Scale ◽  
Cytokine Signaling ◽  
Nasopharyngeal Swab ◽  
The Novel ◽  
Proof Of Concept ◽  
Open Label ◽  
Novel Coronavirus

Abstract Background The rapid emergence and the high disease burden of the novel coronavirus SARS-CoV-2 have created a medical need for readily available drugs that can decrease viral replication or blunt the hyperinflammatory state leading to severe COVID-19 disease. Azithromycin is a macrolide antibiotic, known for its immunomodulatory properties. It has shown antiviral effect specifically against SARS-CoV-2 in vitro and acts on cytokine signaling pathways that have been implicated in COVID-19. Methods DAWn-AZITHRO is a randomized, open-label, phase 2 proof-of-concept, multicenter clinical trial, evaluating the safety and efficacy of azithromycin for treating hospitalized patients with COVID-19. It is part of a series of trials testing promising interventions for COVID-19, running in parallel and grouped under the name DAWn-studies. Patients hospitalized on dedicated COVID wards are eligible for study inclusion when they are symptomatic (i.e., clinical or radiological signs) and have been diagnosed with COVID-19 within the last 72 h through PCR (nasopharyngeal swab or bronchoalveolar lavage) or chest CT scan showing typical features of COVID-19 and without alternate diagnosis. Patients are block-randomized (9 patients) with a 2:1 allocation to receive azithromycin plus standard of care versus standard of care alone. Standard of care is mostly supportive, but may comprise hydroxychloroquine, up to the treating physician’s discretion and depending on local policy and national health regulations. The treatment group receives azithromycin qd 500 mg during the first 5 consecutive days after inclusion. The trial will include 284 patients and recruits from 15 centers across Belgium. The primary outcome is time from admission (day 0) to life discharge or to sustained clinical improvement, defined as an improvement of two points on the WHO 7-category ordinal scale sustained for at least 3 days. Discussion The trial investigates the urgent and still unmet global need for drugs that may impact the disease course of COVID-19. It will either provide support or else justify the discouragement of the current widespread, uncontrolled use of azithromycin in patients with COVID-19. The analogous design of other parallel trials of the DAWN consortium will amplify the chance of identifying successful treatment strategies and allow comparison of treatment effects within an identical clinical context. Trial registration EU Clinical trials register EudraCT Nb 2020-001614-38. Registered on 22 April 2020

scholarly journals Efficacy and Biomarker Analysis of Adavosertib in Differentiated Thyroid Cancer

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3487
Author(s):  
Yu-Ling Lu ◽  
Ming-Hsien Wu ◽  
Yi-Yin Lee ◽  
Ting-Chao Chou ◽  
Richard J. Wong ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Cell Lines ◽  
Differentiated Thyroid Cancer ◽  
Xenograft Model ◽  
In Vivo Studies ◽  
Follicular Thyroid Cancer ◽  
Biomarker Analysis ◽  
Cancer Tumor

Differentiated thyroid cancer (DTC) patients are usually known for their excellent prognoses. However, some patients with DTC develop refractory disease and require novel therapies with different therapeutic mechanisms. Targeting Wee1 with adavosertib has emerged as a novel strategy for cancer therapy. We determined the effects of adavosertib in four DTC cell lines. Adavosertib induces cell growth inhibition in a dose-dependent fashion. Cell cycle analyses revealed that cells were accumulated in the G2/M phase and apoptosis was induced by adavosertib in the four DTC tumor cell lines. The sensitivity of adavosertib correlated with baseline Wee1 expression. In vivo studies showed that adavosertib significantly inhibited the xenograft growth of papillary and follicular thyroid cancer tumor models. Adavosertib therapy, combined with dabrafenib and trametinib, had strong synergism in vitro, and revealed robust tumor growth suppression in vivo in a xenograft model of papillary thyroid cancer harboring mutant BRAFV600E, without appreciable toxicity. Furthermore, combination of adavosertib with lenvatinib was more effective than either agent alone in a xenograft model of follicular thyroid cancer. These results show that adavosertib has the potential in treating DTC.

scholarly journals Cytocidal Antitumor Effects against Human Ovarian Cancer Cells Induced by B-Lactam Steroid Alkylators with Targeted Activity against Poly (ADP-Ribose) Polymerase (PARP) Enzymes in a Cell-Free Assay

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1028
Author(s):  
Nikolaos Nikoleousakos ◽  
Panagiotis Dalezis ◽  
Aikaterini Polonifi ◽  
Elena G. Geromichalou ◽  
Sofia Sagredou ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Mrna Expression ◽  
Cancer Cells ◽  
Cell Lines ◽  
Synthetic Lethality ◽  
Parp Inhibitor ◽  
Positive Control ◽  
Ovarian Cancer Cells ◽  
Antitumor Effects

We evaluated three newly synthesized B-lactam hybrid homo-aza-steroidal alkylators (ASA-A, ASA-B and ASA-C) for their PARP1/2 inhibition activity and their DNA damaging effect against human ovarian carcinoma cells. These agents are conjugated with an alkylating component (POPA), which also served as a reference molecule (positive control), and were tested against four human ovarian cell lines in vitro (UWB1.289 + BRCA1, UWB1.289, SKOV-3 and OVCAR-3). The studied compounds were thereafter compared to 3-AB, a known PARP inhibitor, as well as to Olaparib, a standard third-generation PARP inhibitor, on a PARP assay investigating their inhibitory potential. Finally, a PARP1 and PARP2 mRNA expression analysis by qRT-PCR was produced in order to measure the absolute and the relative gene expression (in mRNA transcripts) between treated and untreated cells. All the investigated hybrid steroid alkylators and POPA decreased in vitro cell growth differentially, according to the sensitivity and different gene characteristics of each cell line, while ASA-A and ASA-B presented the most significant anticancer activity. Both these compounds induced PARP1/2 enzyme inhibition, DNA damage (alkylation) and upregulation of PARP mRNA expression, for all tested cell lines. However, ASA-C underperformed on average in the above tasks, while the compound ASA-B induced synthetic lethality effects on the ovarian cancer cells. Nevertheless, the overall outcome, leading to a drug-like potential, provides strong evidence toward further evaluation.

scholarly journals The Novel Dihydroorotate Dehydrogenase (DHODH) Inhibitor PTC299 Inhibit De Novo Pyrimidine Synthesis with Broad Anti-Leukemic Activity Against Acute Myeloid Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 8-9
Author(s):  
Sujan Piya ◽  
Marla Weetall ◽  
Josephine Sheedy ◽  
Balmiki Ray ◽  
Huaxian Ma ◽  
...  
Keyword(s):  
Dna Damage ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
De Novo ◽  
Dihydroorotate Dehydrogenase ◽  
Nucleotide Synthesis ◽  
Inhibition Of Proliferation ◽  
Acute Myeloid

Introduction: Acute myeloid leukemia (AML) is characterized by both aberrant proliferation and differentiation arrest at hematopoietic progenitor stages 1,2. AML relies upon de novo nucleotide synthesis to meet a dynamic metabolic landscape and to provide a sufficient supply of nucleotides and other macromolecules 3,4. Hence, we hypothesized that inhibition of de novo nucleotide synthesis would lead to depletion of the nucleotide pool and pyrimidine starvation in leukemic cells compared to their non-malignant counterparts and impact proliferative and differentiation inhibition pathways. PTC299 is an inhibitor of dihydroorotate dehydrogenase (DHODH), a rate limiting enzyme for de novo pyrimidine nucleotide synthesis that is currently in a clinical trial for the treatment of AML. Aim: We investigated the pre-clinical activity of PTC299 against AML in primary AML blasts and cytarabine-resistant cell lines. To confirm that PTC299 effects are due to inhibition of de novo pyrimidine nucleotide synthesis for leukemic growth, we specifically tested the impact of uridine and orotate rescue. In addition, a comprehensive analysis of alteration of metabolic signaling in PI3K/AKT pathways, apoptotic signatures and DNA damage responses were analyzed by Mass cytometry based proteomic analysis (CyTOF) and immunoblotting. The potential clinical relevance of DHODH inhibition was confirmed in an AML-PDX model. Results: The IC50s for all tested cell lines (at 3 day) and primary blasts (at 5-7 day) were in a very low nanomolar range: OCI-AML3 -4.43 nM, HL60 -59.7 nM and primary samples -18-90 nM. Treatment of AML in cytarabine-resistant cells demonstrated that PTC299 induced apoptosis, differentiation, and reduced proliferation with corresponding increase in Annexin V and CD14 positive cells (Fig.1). PTC299-induced apoptosis and inhibition of proliferation was rescued by uridine and orotate. To gain more mechanistic insights, we used an immunoblotting and mass cytometry (CyTOF) based approach to analyze changes in apoptotic and cell signaling proteins in OCI-AML3 cells. Apoptotic pathways were induced (cleaved PARP, cleaved Caspase-3) and DNA damage responses (TP53, γH2AX) and the PI3/AKT pathway were downregulated in response to PTC299. In isogenic cell lines, p53-wildtype cells were sustained and an increased DNA damage response with corresponding increase in apoptosis in comparison to p53-deficient cells was shown. (Fig.2) In a PDX mouse model of human AML, PTC299 treatment improved survival compared to mice treated with vehicle (median survival 40 days vs. 30 days, P=0.0002) (Fig.3). This corresponded with a reduction in the bone marrow burden of leukemia with increased expression of differentiation markers in mice treated with PTC299 (Fig.3). Conclusion: PTC299 is a novel dihydroorotate dehydrogenase (DHODH) inhibitor that triggers differentiation, apoptosis and/or inhibition of proliferation in AML and is being tested in a clinical trials for the treatment of acute myeloid malignancies. Reference: 1. Thomas D, Majeti R. Biology and relevance of human acute myeloid leukemia stem cells. Blood 2017; 129(12): 1577-1585. e-pub ahead of print 2017/02/06; doi: 10.1182/blood-2016-10-696054 2. Quek L, Otto GW, Garnett C, Lhermitte L, Karamitros D, Stoilova B et al. Genetically distinct leukemic stem cells in human CD34- acute myeloid leukemia are arrested at a hemopoietic precursor-like stage. The Journal of experimental medicine 2016; 213(8): 1513-1535. e-pub ahead of print 2016/07/06; doi: 10.1084/jem.20151775 3. Villa E, Ali ES, Sahu U, Ben-Sahra I. Cancer Cells Tune the Signaling Pathways to Empower de Novo Synthesis of Nucleotides. Cancers (Basel) 2019; 11(5). e-pub ahead of print 2019/05/22; doi: 10.3390/cancers11050688 4. DeBerardinis RJ, Chandel NS. Fundamentals of cancer metabolism. Sci Adv 2016; 2(5): e1600200. e-pub ahead of print 2016/07/08; doi: 10.1126/sciadv.1600200 Disclosures Weetall: PTC Therapeutic: Current Employment. Sheedy:PTC therapeutics: Current Employment. Ray:PTC Therapeutics Inc.: Current Employment. Konopleva:Genentech: Consultancy, Research Funding; Rafael Pharmaceutical: Research Funding; Ablynx: Research Funding; Ascentage: Research Funding; Agios: Research Funding; Kisoji: Consultancy; Eli Lilly: Research Funding; AstraZeneca: Research Funding; Reata Pharmaceutical Inc.;: Patents & Royalties: patents and royalties with patent US 7,795,305 B2 on CDDO-compounds and combination therapies, licensed to Reata Pharmaceutical; AbbVie: Consultancy, Research Funding; Calithera: Research Funding; Cellectis: Research Funding; Amgen: Consultancy; Stemline Therapeutics: Consultancy, Research Funding; Forty-Seven: Consultancy, Research Funding; F. Hoffmann La-Roche: Consultancy, Research Funding; Sanofi: Research Funding. Andreeff:Amgen: Research Funding; Daiichi-Sankyo; Jazz Pharmaceuticals; Celgene; Amgen; AstraZeneca; 6 Dimensions Capital: Consultancy; Daiichi-Sankyo; Breast Cancer Research Foundation; CPRIT; NIH/NCI; Amgen; AstraZeneca: Research Funding; Centre for Drug Research & Development; Cancer UK; NCI-CTEP; German Research Council; Leukemia Lymphoma Foundation (LLS); NCI-RDCRN (Rare Disease Clin Network); CLL Founcdation; BioLineRx; SentiBio; Aptose Biosciences, Inc: Membership on an entity's Board of Directors or advisory committees. Borthakur:BioLine Rx: Consultancy; BioTherix: Consultancy; Nkarta Therapeutics: Consultancy; Treadwell Therapeutics: Consultancy; Xbiotech USA: Research Funding; Polaris: Research Funding; AstraZeneca: Research Funding; BMS: Research Funding; BioLine Rx: Research Funding; Cyclacel: Research Funding; GSK: Research Funding; Jannsen: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Incyte: Research Funding; PTC Therapeutics: Research Funding; FTC Therapeutics: Consultancy; Curio Science LLC: Consultancy; PTC Therapeutics: Consultancy; Argenx: Consultancy; Oncoceutics: Research Funding.

scholarly journals Autophagy and Ubiquitin-Mediated Proteolytic Degradation of PML/Rarα Fusion Protein in Matrine-Induced Differentiation Sensitivity Recovery of ATRA-Resistant APL (NB4-LR1) Cells: in Vitro and in Vivo Studies

2018 ◽  
Vol 48 (6) ◽  
pp. 2286-2301 ◽  
Author(s):  
Dijiong  Wu ◽  
Keding Shao ◽  
Qihao Zhou ◽  
Jie Sun ◽  
Ziqi Wang ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Fusion Protein ◽  
Cell Lines ◽  
Mrna Level ◽  
In Vivo Studies ◽  
Proteolytic Degradation ◽  
Induced Differentiation ◽  
Fluorescent Substrate

Background/Aims: Although the cure rate of acute promyelocytic leukemia (APL) has exceeded 90%, the relapse/refractory APL that resistant to all-trans retinoic acid (ATRA) or ATO was still serious concern. Matrine (MAT) could improve the differentiation ability of ATRA-resistant APL cells. This study aimed to explore how the APL-specific fusion protein was degraded in ATRA-resistant APL with the application of MAT and ATRA. Methods: ATRA-sensitive (NB4) and ATRA-resistant (NB4-LR1) cell lines were used. Nitroblue tetrazolium reduction assay and flow cytometry were used to detect the differentiation ability. The activity of ubiquitin-proteasome and autophagy-mediated pathways in both cells treated with ATRA with or without MAT were compared in protein and mRNA level (Western blot analysis, qRT-PCR), the Fluorescent substrate Suc-LLVY-AMC detection was used to detect the activity of proteasome, and electron microscope for observing autophagosome. MG 132(proteasome inhibitor), rapamycin (autophagy activator), hydroxychloroquine (lysosomal inhibitor) and STI571 [retinoic acid receptor alpha (RARα) ubiquitin stabilizer] were used as positive controls. The effect of MAT was observed in vivo using xenografts. Results: MAT improved the sensitivity of NB4-LR1cells to ATRA treatment, which was consistent with the expression of PML-RARα fusion protein. MAT promoted the ubiquitylation level in NB4-LR1. MG 132 induced the decrease in RARα in both cell lines, and hampered the differentiation of NB4 cells. MAT also promoted the autophagy in NB4-LR1 cells, with an increase in microtubule-associated protein 1 light chain3 (LC3)-II and LC3-II/LC3-I ratio and exhaustion of P62. The expression of LC3II increased significantly in the MAT and ATRA + MAT groups in combination with lysosomal inhibitors. A similar phenomenon was observed in mouse xenografts. MAT induced apoptosis and differentiation. Conclusions: Autophagy and ubiquitin-mediated proteolytic degradation of PML/RARα fusion protein are crucial in MAT-induced differentiation sensitivity recovery of NB4-LR1 cells.

Use of Medium Potency Statins Is Associated with Improved Outcomes after Frontline RCHOP in Patients with Diffuse Large B-Cell Lymphoma (DLBCL)

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 45-45
Author(s):  
Sushanth Gouni ◽  
Paolo Strati ◽  
Jason Westin ◽  
Loretta J. Nastoupil ◽  
Raphael E Steiner ◽  
...  
Keyword(s):  
Cell Lines ◽  
Research Funding ◽  
Response Assessment ◽  
Cholesterol Content ◽  
In Vivo Studies ◽  
High Cholesterol ◽  
Improved Outcomes ◽  
Significant Difference

Background: Pre-clinical studies show that statins may improve the efficacy of chemoimmunotherapy in patients with DLBCL, through interference with cell membrane-initiated signaling pathways. Clinical retrospective studies, however, yield conflicting data, due to heterogeneous properties of statins, including potency and hydrophilicity. Methods: This is a retrospective analysis of patients with previously untreated, advanced stage DLBCL, non-double hit, treated with frontline R-CHOP between 01/01/2000 and 09/01/2019 (data cut-off 04/15/2020) at MD Anderson Cancer Center, and for whom data regarding statin use at time of initiation of treatment were available. Lugano 2014 response criteria were applied retrospectively for response assessment. Cellular cholesterol levels were analyzed in 6 DLBCL cell lines using an Amplex red fluorometric assay. A doxorubicin (DXR)-resistant cell line was generated exposing SUDHL4 cells to escalating doses of DXR; a DXR-resistant DLBCL patient-derived xenograft (PDX) model was established through serial transplantation and exposure to DXR. Results: 271 patients were included in the analysis, 182 (67%) were older than 60 years, 134 (49%) were male, 212 (72%) had stage IV disease, and 217 (80%) had an IPI score > 3; upon pathological review, 38 (36%) cases were non-GCB type, and 18 (28%) were double-expressors; 214 (79%) were able to complete all planned 6 cycles of RCHOP. Seventy-nine (29%) patients received statins at time of initiation of chemoimmunotherapy: 15 patients received low potency statin, 51 medium and 13 high; 18 patients received hydrophilic statins and 61 lipophilic. Patients receiving statins were significantly older as compared to patients who did not (p<0.001); no other significant difference in baseline characteristics was observed when comparing the 2 groups. Overall, 265 out of 271 patients were evaluable for response, as 6 stopped treatment because of toxicity before first response assessment. Among these, ORR was 95% (252/265) and CR rate was 62% (165/265). ORR rate was identical in patients who were treated with statin and those who did not (95% both, p=1). After a median follow-up of 77 months (95% CI, 70-84 months), 119 patients progressed/died, median PFS was not reached and 6-year PFS was 57%. 6-year PFS rate according to statin intensity was: 48% (low), 72% (medium), 57% (high). PFS. 6-year PFS rate was 64% for hydrophilic and 72% for lipophilic statins. Patients treated with statins had a trend for longer PFS (p=0.06), significantly longer for patients receiving medium potency statins (p=0.04). No significant difference in PFS was observed when comparing patients treated with lipophilic statins to all others (not reached vs 84 months, p=0.22). To confirm these clinical data, in-vitro and in-vivo studies were performed. Six cell lines were tested: 4 with high cholesterol content (SUDHL4, HBL1, HT, and U2932; 5.0-8.0 µg/mg protein), and 2 with low cholesterol content (DOHH2 and OCI-LY19; 1.5-2.0 µg/mg protein); the latter showed the highest sensitivity to DXR-mediated killing. The combination of lovastatin and DXR (10nM) was tested in all 4 cell lines with high cholesterol content, resulting in more cell death than either treatment alone. Lovastatin (at the nanomolar range) resensitized DXR-resistant SUDHL4 cells to DXR. Finally, in a DXR-resistant PDX model, the combination of lovastatin and DXR resulted in delayed tumor growth as compared to chemotherapy alone. Conclusions: Use of medium potency statins is associated with improved outcomes after frontline RCHOP in patients with DLBCL. This was further confirmed in functional in-vitro and in-vivo studies. Future interventional studies, aimed at improving outcomes in these patients using this novel combination, are warranted. Disclosures Westin: Amgen: Consultancy; 47: Research Funding; Kite: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Curis: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding. Nastoupil:Gamida Cell: Honoraria; Merck: Research Funding; TG Therapeutics: Honoraria, Research Funding; Karus Therapeutics: Research Funding; Janssen: Honoraria, Research Funding; LAM Therapeutics: Research Funding; Novartis: Honoraria, Research Funding; Bayer: Honoraria; Celgene: Honoraria, Research Funding; Genentech, Inc.: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Gilead/KITE: Honoraria. Neelapu:Bristol-Myers Squibb: Other: personal fees, Research Funding; Merck: Other: personal fees, Research Funding; Kite, a Gilead Company: Other: personal fees, Research Funding; Pfizer: Other: personal fees; Celgene: Other: personal fees, Research Funding; Novartis: Other: personal fees; Karus Therapeutics: Research Funding; N/A: Other; Takeda Pharmaceuticals: Patents & Royalties; Acerta: Research Funding; Cellectis: Research Funding; Poseida: Research Funding; Precision Biosciences: Other: personal fees, Research Funding; Legend Biotech: Other; Adicet Bio: Other; Allogene Therapeutics: Other: personal fees, Research Funding; Cell Medica/Kuur: Other: personal fees; Calibr: Other; Incyte: Other: personal fees; Unum Therapeutics: Other, Research Funding. Landgraf:NCI/NIH: Research Funding. Vega:NCI: Research Funding.

Targeting MDM2-dependent serine metabolism as a therapeutic strategy for liposarcoma

2020 ◽  
Vol 12 (547) ◽  
pp. eaay2163
Author(s):  
Madi Y. Cissé ◽  
Samuel Pyrdziak ◽  
Nelly Firmin ◽  
Laurie Gayte ◽  
Maud Heuillet ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Negative Regulator ◽  
Nucleotide Synthesis ◽  
Metabolic Functions ◽  
Xenograft Models ◽  
Well Differentiated ◽  
Serine Metabolism

Well-differentiated and dedifferentiated liposarcomas (LPSs) are characterized by a systematic amplification of the MDM2 oncogene, which encodes a key negative regulator of the p53 pathway. The molecular mechanisms underlying MDM2 overexpression while sparing wild-type p53 in LPS remain poorly understood. Here, we show that the p53-independent metabolic functions of chromatin-bound MDM2 are exacerbated in LPS and mediate an addiction to serine metabolism that sustains nucleotide synthesis and tumor growth. Treatment of LPS cells with Nutlin-3A, a pharmacological inhibitor of the MDM2-p53 interaction, stabilized p53 but unexpectedly enhanced MDM2-mediated control of serine metabolism by increasing its recruitment to chromatin, likely explaining the poor clinical efficacy of this class of MDM2 inhibitors. In contrast, genetic or pharmacological inhibition of chromatin-bound MDM2 by SP141, a distinct MDM2 inhibitor triggering its degradation, or interfering with de novo serine synthesis, impaired LPS growth both in vitro and in clinically relevant patient-derived xenograft models. Our data indicate that targeting MDM2 functions in serine metabolism represents a potential therapeutic strategy for LPS.

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