Biology subjects

Buckley, S. M.

Publications and source records attributed to Buckley, S. M..

5 recordsLinked to original sources

bioRxiv2026

Proteome landscape of B-cell malignancies identifies mantle cell lymphoma protein signature

Mantle cell lymphoma (MCL) is one of the deadliest forms of Non-Hodgkins B-cell lymphoma. Typically, patients present with both overexpression of CyclinD1 and secondary mutations identified by genomic sequencing. Although MCL patients may initially respond to treatment, they eventually relapse and succumb to disease, highlighting the essential need to identify new targets for treatment. Here we performed proteomic profiling of healthy B cells and three different forms of B-cell malignancies, including MCL, to define the proteomic signature of MCL. We compared the proteome of each to MCL and identified 10 proteins that are specifically upregulated in MCL. Of these 10 proteins, seven of them show no transcriptional changes and have been overlooked by conventional RNA expression analysis. Further analysis of the proteomic signature reveals potential avenues for dual targeting in CAR T-cell therapy and provides guidance for personalized therapeutics based on protein expression. STATEMENT OF SIGNIFICANCEWe present a resource defining the protein landscape of MCL, CLL, and FL as compared to healthy b cells identified utilizing quantitative proteomics from primary patient samples. Applied to MCL, our results identify 10 proteins specifically upregulated in MCL that may prove to be therapeutic targets to treat the disease.

cancer biology↗

bioRxiv2025

The Splicing Factor PTBP1 interacts with RUNX1 and is Required for Leukemia Cell Survival

Runt-related Transcription Factor 1 (RUNX1) is essential for definitive hematopoiesis and is among the most frequently mutated genes in leukemia. Previous work from our lab demonstrated that Histone Deacetylase 1 (HDAC1), a known RUNX1 partner, is unexpectedly required for active transcription suggesting a non-histone role for HDAC1 regulating components of the RUNX1 complex. Here, we use proteomics, genomics, and long-read transcriptomics to identify novel RUNX1 interacting partners and decipher their role in gene regulation and RNA splicing in leukemia cells. We demonstrate that Polypyrimidine Tract Binding Protein 1 (PTBP1) interacts with RUNX1 in an HDAC1 dependent manner. Chromatin profiling revealed extensive genome-wide overlap in sites occupied by RUNX1 and PTBP1, with significant enrichment at promoters of actively transcribed genes. Loss of PTBP1 in AML cells led to widespread alterations in RNA splicing and decreased expression of genes whose promoters are bound by both factors, including metabolic genes. In agreement with these findings, we found that loss of PTBP1 reduced glycolysis and glucose uptake and ultimately caused cell death. Based on our data, we propose that the interaction between RUNX1 and PTBP1 facilitates expression of metabolic proteins essential for leukemia cell growth and survival. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=92 SRC="FIGDIR/small/654547v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@74e3b9org.highwire.dtl.DTLVardef@12a090org.highwire.dtl.DTLVardef@eb5a48org.highwire.dtl.DTLVardef@17465dc_HPS_FORMAT_FIGEXP M_FIG C_FIG KEY POINTSO_LIPTBP1 binds RUNX1 in a HDAC1-dependent manner and co-localizes to the promoters of target genes in leukemia cells. C_LIO_LILoss of PTBP1 decreases expression of key metabolic genes, resulting in decreased cell growth and glycolysis, increased sensitivity to chemotherapy, and cell death. C_LI

cancer biology↗

bioRxiv2024

Small molecule targeting of FBXO21 mediated p85αubiquitylation in acute myeloid leukemia

PI3K inhibitors that target the catalytic sub-unit p110 are used in cancer therapy to inhibit overactive PI3K signaling pathway. However, their clinical use is limited by severe adverse effects and development of resistance, highlighting the need for further research on regulation of the PI3K pathway. We have identified that FBXO21 ubiquitinates regulatory PI3K subunit p85, and silencing of FBXO21 inhibits canonical PI3K signaling. To target FBXO21, we developed a small molecule designed to interfere with substrate:ligase interaction. Our novel small molecule effectively blocks p85 ubiquitination leading to decreased PI3K pathway activation and cell death in acute myeloid leukemia (AML). Moreover, our studies demonstrate selectivity for AML cells over healthy counterparts, and elimination of AML in vivo, emphasizing FBXO21s potential as a promising therapeutic target for AML. Targeting substrate:ligase interactions provide new avenues for drug discovery that may enhance the efficacy of current therapies and benefits for improving patient outcomes. STATEMENT OF SIGNIFICANCEOur studies highlight the potential of the ubiquitin E3 ligase FBXO21 as an alternative therapeutic target for the PI3K signaling pathway, not only in AML but in cancers with aberrant PI3K signaling.

cancer biology↗

bioRxiv2019

E3 Ligase UBR5 HECT domain mutations in lymphoma control maturation of B cells via alternative splicing

Coordination of a number of molecular mechanisms including transcription, alternative splicing, and class switch recombination are required to facilitate development, activation, and survival of B cells. Disruption of these pathways can result in malignant transformation. Recently, next generation sequencing has identified a number of novel mutations in mantle cell lymphoma (MCL) patients including the ubiquitin E3 ligase UBR5. Approximately 18% of MCL patients were found to have mutations in UBR5 with the majority of mutations within the HECT domain of the protein which can accept and transfer ubiquitin molecules to the substrate. Determining if UBR5 controls the maturation of B cells is important to fully understand malignant transformation to MCL. To elucidate the role of UBR5 in B cell maturation and activation we generated a conditional mutant disrupting UBR5s C-terminal HECT domain. Loss of the UBR5 HECT domain leads to a block in maturation of B cells in the spleen and up-regulation of proteins associated with mRNA splicing via the spliceosome. Our studies reveal a novel role of UBR5 in B cell maturation by regulating alternative splicing of key transcripts during B cell development and suggests UBR5 mutations may promote mantle cell lymphoma initiation.\n\nKEY POINTSO_LIUtilizing a novel mouse model mimicking MCL patient mutations, the loss of UBR5s HECT domain causes alterations in B cell development.\nC_LIO_LIUBR5 mutations lead to stabilization of UBR5 and aberrant splicing.\nC_LI

immunology↗

bioRxiv2019

Loss of FBXO9 enhances proteasome activity and promotes aggressiveness in acute myeloid leukemia

The hematopoietic system is maintained throughout life by hematopoietic stem cells that are capable of differentiating into all hematopoietic lineages. An intimate balance between self-renewal, differentiation, and quiescence is required to maintain hematopoiesis. Disruption of this balance can result in hematopoietic malignancy, including acute myeloid leukemia (AML). FBXO9, from the F-box E3 ubiquitin ligases, is down-regulated in patients with AML compared to normal bone marrow. FBXO9 is the substrate recognition component of the Skp1-Cullin-F-box (SCF)-type E3 ligase complex. FBXO9 is highly expressed in hematopoietic stem and progenitor populations, which contain the tumor-initiating population in AML. In AML patients, decrease in FBXO9 expression is most pronounced in patients with the inversion of chromosome 16 (inv(16)), a rearrangement that generates the transcription factor fusion gene, CBFB-MYH11. To study FBXO9 in malignant hematopoiesis, we generated a conditional knockout mouse model using a novel CRISPR/Cas9 strategy. Our data show that deletion of Fbxo9 in mice expressing Cbfb-MYH11 leads to markedly accelerated and aggressive leukemia development. In addition, we find loss of FBXO9 leads to increased proteasome expression and tumors are more sensitive to bortezomib suggesting that FBXO9 expression may predict patient response to bortezomib treatment.

cancer biology↗