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:To elucidate the underlying mechanisms of resistance to venetoclax and dexitabine combination therapy, we performed transcriptomic analysis of VEN/DEC pre- and post-treatment samples from AML patients enrolled in the DEC10-VEN clinical trial (NCT03404193). We have reported that AML cells from non-responders show a significant upregulation of the mRNA expression of the fatty acid metabolism activator PPARG (Peroxisome Proliferator-Activated Receptor γ) after VEN/DEC treatment.
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:Venetoclax (ven) combined with the hypomethylating agent azacytidine (aza) is a widely used therapy for Acute Myeloid Leukemia (AML), however, most patients develop resistance. A genome-wide CRISPR screen showed that loss of genes involved in translation conferred sensitivity to ven but not ven+palbo. Accordingly, we show that increased translation occurs after AML cells are challenged with ven, and ven+palbo blocks this increase. We also found that loss of BAX, which leads to ven resistance, was overcome by combination with CDK4/6 inhibitors. Conversely, loss of RB1, a known mechanism of resistance to CDK4/6 inhibitors, was mitigated by ven+palbo. This work suggests that the combination of ven+palbo is a potential novel therapy for AML for potential subpopulations that may benefit the most from this treatment, as well as targeting translation as a means to overcome ven resistance.
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:Venetoclax (ven) combined with the hypomethylating agent azacytidine (aza) is a widely used therapy for Acute Myeloid Leukemia (AML), however, most patients develop resistance. Using RNASeq, we identified loss of Ikaros (IKZF1) as a potential resistance mechanism to ven+palbo. Examination of cells with IKZF1-loss revealed upregulation of the receptor, AXL, with concordant AXL inhibitor sensitivity in AML tumors harboring IKZF1 mutations. This work suggests that the combination of ven+palbo is a potential novel therapy for AML for potential subpopulations that may benefit the most from this treatment, as well as targeting translation as a means to overcome ven 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:Background: The combination of hypomethylating agents (HMA) with the Bcl-2 inhibitor venetoclax (VEN) has significantly advanced acute myeloid leukemia (AML) treatment. This therapy is approved for older patients and those with comorbidities. Objectives: We aimed to identify resistance mechanisms to HMA-VEN therapy using scRNA-Seq on primary AML samples. GLUT5 expression on AML progenitors from resistant and non-resistant patients was evaluated through immunoblotting and immunofluorescence. Seahorse and CRISPR experiments were conducted to validate the phenotype in the THP-1 AML monocyte cell line. Findings: scRNA-Seq revealed an upregulation of Leukemia Stem Cell (LSC) 17 scores in pre-treatment samples compared to HMA-VEN relapse samples. RNA velocity analysis indicated that LSCs in pre-treatment samples were the root cell population, while HMA-VEN relapse cells, specifically AML Blast 1, showed preferential splicing of PHGDH, a key serine synthesis pathway member, resulting in the overexpression of SLC2A5. GLUT5 was more frequently and intensely expressed on the cell surface in patients resistant to HMA-VEN. Seahorse assays demonstrated that fructose uptake via GLUT5 suppressed oxygen consumption in THP-1 cells following siRNA-mediated knockdown. Conclusions: Aberrant GLUT5 expression by leukemia progenitors represents a metabolic adaptation contributing to VEN resistance in AML.