Project description:B-cell receptor (BCR) signaling is a central driver in chronic lymphocytic leukemia (CLL), along with activation of pro-survival pathways (e.g., NF- κB) and aberrant anti-apoptotic (e.g., BCL2), culminating to CLL cell survival and drug-resistance. Front-line targeted therapies such as ibrutinib (IBR) and venetoclax (VEN) have radically improved CLL management. Yet, persisting CLL cells lead to relapse in ~20% of patients, signifying the need for alternative therapeutics with novel approaches to CLL cell elimination and overcoming resistance mechanisms. SpiD3 is a novel spirocyclic dimer of analog 19 displaying NF-κB inhibitory activity. Recently, we have shown that SpiD3 inhibits CLL proliferation and induces cytotoxicity, by promoting futile activation of the unfolded response pathway (UPR) and generation of reactive oxygen species (ROS), resulting in insurmountable endoplasmic reticulum stress. RNA-sequencing analysis of IBR- and VEN-resistant CLL cell lines revealed ferroptosis, UPR signaling, and oxidative stress among the top pathways modulated by SpiD3 treatment. By examining SpiD3 induced protein aggregation, ROS production, and ferroptosis in preclinical models of CLL, our data demonstrates marked SpiD3-induced anti-leukemic properties and CLL cell cytotoxicity, including in cell lines resistant to current front-line therapeutics, substantiating the development of SpiD3 as a novel therapeutic approach to management of relapse/refractory CLL disease.
Project description:Deep single-cell multi-omic profiling of drug resistance in patients with relapsed or refractory (rr) acute myeloid leukemia (AML) is a promising approach to understand and identify the molecular and cellular determinants of drug resistance. Here, we address this challenge by integrating single-cell ex vivo drug profiling (pharmacoscopy) with both bulk and single-cell resolved DNA, RNA, and protein profiling, as well as clinical annotations across samples of a cohort of 21 rrAML patients. Unsupervised data integration revealed ex vivo response to the Bcl-2 inhibitor venetoclax (VEN) to be significantly reduced in patients treated with the combination of a hypomethylating agent (HMA) and VEN compared to patients pre-exposed to HMA only, while also exposing innate Ven resistance in a subset of VEN-naive patients. Systematic molecular integration retrieved known and novel molecular mechanisms underlying VEN resistance and identified alternative therapeutic strategies in VEN resistant samples, including targeting increased proliferation by PLK inhibitor volasertib. Across data modalities, high CD36 expression on AML blasts was associated with VENres, while CD36-targeted antibody treatment ex vivo revealed striking sensitivity in VEN resistant AML. In summary, we showcase how single-cell multi-omic and functional profiling can facilitate the discovery of drug resistance mechanisms and emergent treatment vulnerabilities. Our dataset represents a comprehensive molecular and functional profiling of rrAML at single-cell resolution, providing a valuable resource for future studies.
Project description:Single-cell RNA-sequencing and other genome-wide approaches were applied to a cohort of CLL patients receiving Venetoclax treatment to study mechanisms of resistance.
Project description:B cell chronic lymphocytic leukemia - A model with immune response
Seema Nanda 1, , Lisette dePillis 2, and Ami Radunskaya 3,
1.
Tata Institute of Fundamental Research, Centre for Applicable Mathematics, Bangalore 560065, India
2.
Department of Mathematics, Harvey Mudd College, Claremont, CA 91711
3.
Department of Mathematics, Pomona College, Claremont, CA, 91711, United States
Abstract
B cell chronic lymphocytic leukemia (B-CLL) is known to have substantial clinical heterogeneity. There is no cure, but treatments allow for disease management. However, the wide range of clinical courses experienced by B-CLL patients makes prognosis and hence treatment a significant challenge. In an attempt to study disease progression across different patients via a unified yet flexible approach, we present a mathematical model of B-CLL with immune response, that can capture both rapid and slow disease progression. This model includes four different cell populations in the peripheral blood of humans: B-CLL cells, NK cells, cytotoxic T cells and helper T cells. We analyze existing data in the medical literature, determine ranges of values for parameters of the model, and compare our model outcomes to clinical patient data. The goal of this work is to provide a tool that may shed light on factors affecting the course of disease progression in patients. This modeling tool can serve as a foundation upon which future treatments can be based.
Keywords: NK cell, chronic lymphocytic leukemia, mathematical model, T cell., B-CLL.
Project description:Ibrutinib (Ibr), an orally administered covalent inhibitor of Bruton’s kinase, has generated remarkable responses in CLL patients including those with an unfavorable cytogenetic profile. Once patients develop resistance to ibrutinib, the outcome is poor with few treatment options. To further understand the genomic mechanisms underlying Ibr resistance, we’ve performed genome wide copy number analysis of serial samples collected from nine ibrutinib-relapsed patients. Deletions of 18p often coincide with del(17p)/TP53 mutations, predispose patients to relapse.
Project description:Acute myeloid leukemia (AML) is a hematopoietic cancer characterized by the proliferation and accumulation of aberrant immature myeloid progenitor blasts in bone marrow and peripheral blood. Venetoclax (VEN), a selective B-cell lymphoma 2 (BCL-2) inhibitor, has received FDA approval for AML treatment in combination with hypomethylating agents (HMA). However, treatment failure and therapy resistance present an urgent need for new therapies to overcome VEN resistance and enhance VEN efficacy. We propose inhibition of SUMOylation as a novel therapy with the potential to address this need. SUMOylation regulates protein function by covalently attaching Small Ubiquitin-like MOdifier (SUMO) proteins to target proteins via an enzymatic cascade. Our study aims to evaluate the effects of SUMOylation inhibition on anti-AML activity of VEN and dissert the underlying mechanism.
Project description:The combination of venetoclax with azacitidine (ven/aza) has recently emerged as a promising regimen for acute myeloid leukemia (AML), with approximately 70% of newly diagnosed patients achieving complete remission (CR). However, 30% of newly diagnosed and nearly all relapsed patients do not achieve CR with ven/aza. Mechanistically, we previously reported that ven/aza efficacy is based on eradication of AML stem cells through a mechanism involving inhibition of amino acid metabolism, a process which is required in primitive AML cells to drive oxidative phosphorylation. In the present study we demonstrate that resistance to ven/aza occurs as a consequence of up-regulated fatty acid oxidation (FAO), which occurs either as an intrinsic property of RAS pathway mutations, or as a compensatory adaptation in relapsed disease. Utilization of FAO obviates the need for amino acid metabolism into the TCA cycle, thereby rendering ven/aza ineffective. Importantly, we show that pharmacological inhibition of FAO via use of MCL-1 or CPT1 inhibitor drugs restores targeting of ven/aza resistant AML stem cells. Based on these findings we propose that inhibition of FAO is a potential therapeutic strategy to address ven/aza resistance.
Project description:The combination of venetoclax with azacitidine (ven/aza) has recently emerged as a promising regimen for acute myeloid leukemia (AML), with approximately 70% of newly diagnosed patients achieving complete remission (CR). However, 30% of newly diagnosed and nearly all relapsed patients do not achieve CR with ven/aza. Mechanistically, we previously reported that ven/aza efficacy is based on eradication of AML stem cells through a mechanism involving inhibition of amino acid metabolism, a process which is required in primitive AML cells to drive oxidative phosphorylation. In the present study we demonstrate that resistance to ven/aza occurs as a consequence of up-regulated fatty acid oxidation (FAO), which occurs either as an intrinsic property of RAS pathway mutations, or as a compensatory adaptation in relapsed disease. Utilization of FAO obviates the need for amino acid metabolism into the TCA cycle, thereby rendering ven/aza ineffective. Importantly, we show that pharmacological inhibition of FAO via use of MCL-1 or CPT1 inhibitor drugs restores targeting of ven/aza resistant AML stem cells. Based on these findings we propose that inhibition of FAO is a potential therapeutic strategy to address ven/aza resistance.