Biology subjects

Mabe, N. W.

Publications and source records attributed to Mabe, N. W..

6 recordsLinked to original sources

bioRxiv2026

Dehydration/1,6-addition-based Site-specific Bioconjugation Unveils Norepinephrinylation as a Widespread Post-translational Modification in the Cellular Proteome

Norepinephrine (NE) is a key neurotransmitter and hormone involved in diverse physiological and pathological processes. Beyond its canonical non-covalent signaling through binding adrenergic receptors, NE also induces protein post-translational modifications (PTMs), representing an emerging regulatory mechanism. Two major forms of NE-derived PTMs have been proposed: non-enzymatic norepinephrinylation (NEylation) of cysteine residues mediated by NE quinone and transglutaminase 2 (TG2)-catalyzed NEylation of glutamine residues. However, the cellular abundance, biochemical basis, and pathophysiological roles of NEylation remain poorly understood due to limited detection tools. Here, we report a novel bioconjugation chemistry for selective labeling and enrichment of the endogenous NEylation proteome in cell lines and tissues, which is based on acid-catalyzed dehydration and 1,6-addition to thiol probes. This strategy enables fluorescence imaging and chemical proteomic profiling, revealing NEylation as a widespread PTM that affects enzymatic activities of modified proteins, including protein tyrosine-protein phosphatase non-receptor type 11 (PTPN11). Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/731782v3_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@406ac5org.highwire.dtl.DTLVardef@121d6b9org.highwire.dtl.DTLVardef@98354corg.highwire.dtl.DTLVardef@d312ef_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2026

KMT5C-H4K20me3 drives changes in epigenetic landscape independent of H3K9me3

Histone H4 lysine 20 trimethylation (H4K20me3) is a histone modification that is critical in maintaining genome integrity. Dysregulation of H4K20me3 and KMT5C, the major methyltransferase for H4K20me3, occurs commonly in multiple types of cancer but the mechanisms surrounding how they contribute to shaping the epigenomic landscape remains unclear. Here, we show that KMT5C is involved in non-canonical deposition of H4K20me3, independent of H3K9me3, which was previously recognized as a prerequisite for H4K20me3. This novel subtype of H4K20me3 lacks canonical repressive epigenetic signatures and instead overlaps with multiple activating marks. These activating modifications likely contribute to the dynamic changes in transcript levels upon loss of H4K20me3. The mechanism involved in recruiting KMT5C to these loci is independent of HP1, the factor reported to be involved in recruitment of KMT5C to heterochromatin marked with H3K9me3. Instead, biochemical analyses revealed ZNF280C to be a novel interacting partner of KMT5C, with ZNF280C localizing specifically at H3K9me3-/H4K20me3+ sites. Together, these results suggest a novel, non-canonical function of KMT5C-H4K20me3 that protects vulnerable regions of the genome from uncontrolled expression.

genomics↗

bioRxiv2025

KAT6A/B inhibition synergizes with retinoic acid and enhances the efficacy of GD2-targeted immunotherapy in neuroblastoma

High-risk neuroblastoma accounts for about 15% of childhood cancer deaths and arises from precursors of the peripheral sympathetic nervous system. Retinoids are clinically used to inhibit growth of neuroblastoma cells through reconfiguration of the regulatory enhancer landscape. Its effects, however, are completely reversible after drug withdrawal, leading to rapid tumor cell proliferation. Here, we sought to identify epigenetic modifiers that potentiate the antiproliferative effects of retinoids in neuroblastoma. We identified PF-9363, an inhibitor of the histone H3K23 acetyltransferases KAT6A/B, as synergistically inhibiting neuroblastoma growth in combination with retinoids. PF-9363 plus retinoids induces durable growth arrest, which persists beyond retinoid withdrawal in vitro and in vivo with sustained Polycomb-mediated repression of oncogenic transcription factors MYCN, PHOX2B and GATA3. Moreover, PF-9363 plus retinoids increases GD2 expression, rendering neuroblastoma cells more sensitive to anti-GD2 immunotherapy. Overall, our studies demonstrate that KAT6A/B inhibition increases the effectiveness of retinoids and GD2-targeted immunotherapy in neuroblastoma.

cancer biology↗

bioRxiv2024

Lineage-dependence of the neuroblastoma surfaceome defines tumor cell state-dependent and independent immunotherapeutic targets

BackgroundNeuroblastoma is a heterogeneous disease with adrenergic (ADRN)- and therapy resistant mesenchymal (MES)-like cells driven by distinct transcription factor networks. Here, we investigate the expression of immunotherapeutic targets in each neuroblastoma subtype and propose pan-neuroblastoma and cell state specific targetable cell-surface proteins. MethodsWe characterized cell lines, patient-derived xenografts, and patient samples as ADRN-dominant or MES- dominant to define subtype-specific and pan-neuroblastoma gene sets. Targets were validated with ChIP- sequencing, immunoblotting, and flow cytometry in neuroblastoma cell lines and isogenic ADRN-to-MES transition cell line models. Finally, we evaluated the activity of MES-specific agents in vivo and in vitro. ResultsMost immunotherapeutic targets being developed for neuroblastoma showed significantly higher expression in the ADRN subtype with limited expression in MES-like tumor cells. In contrast, CD276 (B7-H3) and L1CAM maintained expression across both ADRN and MES states. We identified several receptor tyrosine kinases (RTKs) enriched in MES-dominant samples and showed that AXL targeting with ADCT-601 was potently cytotoxic in MES-dominant cell lines and showed specific anti-tumor activity in a MES cell line-derived xenograft. ConclusionsImmunotherapeutic strategies for neuroblastoma must address the potential of epigenetic downregulation of antigen density as a mechanism for immune evasion. We identified several RTKs as candidate MES-specific immunotherapeutic target proteins for the elimination of therapy-resistant cells. We hypothesize that the phenomena of immune escape will be less likely when targeting pan-neuroblastoma cell surface proteins such as B7-H3 and L1CAM, and/or dual targeting strategies that consider both the ADRN- and MES-cell states. Key PointsO_LICellular plasticity influences the abundance of immunotherapeutic targets. C_LIO_LISubtype-specific targets may be susceptible to epigenetically-mediated downregulation. C_LIO_LIImmunotherapeutic targets in development, B7-H3 and L1CAM, show "pan-subtype" expression. C_LI Importance of StudyNeuroblastoma is a lethal childhood malignancy that shows cellular plasticity in response to anti-cancer therapies. Several plasma membrane proteins are being developed as immunotherapeutic targets in this disease. Here we define which cell surface proteins are susceptible to epigenetically regulated downregulation during an adrenergic to mesenchymal cell state switch and propose immunotherapeutic strategies to anticipate and circumvent acquired immunotherapeutic resistance.

cancer biology↗

bioRxiv2020

Adaptation and Selection Shape Clonal Evolution During Residual Disease and Recurrence

The survival of residual tumor cells following therapy and their eventual recurrence constitutes one of the biggest obstacles to obtaining cures in breast cancer, but it remains unclear how the clonal composition of tumors changes during tumor relapse. We used cellular barcoding to directly monitor clonal dynamics during tumor recurrence in a genetically engineered mouse model. We found that the clonal diversity of tumors progressively decreased during tumor regression, residual disease, and recurrence. Only a fraction of subclones survived oncogene withdrawal and persisted in residual tumors. The minimal residual disease phase itself was accompanied by a continued attrition of clones, suggesting an ongoing process of selection during dormancy. The reactivation of dormant residual cells into recurrent tumors followed several distinct evolutionary routes. Approximately half of the recurrent tumors exhibited a striking clonal dominance in which one or two subclones comprised the vast majority of the tumor. The majority of these clonal recurrent tumors exhibited evidence of de novo acquisition of Met amplification, and were sensitive to small-molecule Met inhibitors. A second group of recurrent tumors exhibited marked polyclonality, with thousands of subclones and a clonal architecture very similar to primary tumors. These polyclonal recurrent tumors were not sensitive to Met inhibitors, but were instead dependent upon an autocrine IL-6 - Stat3 pathway. These results suggest that the survival and reactivation of dormant tumors can proceed via multiple independent routes, producing recurrent tumors with distinct clonal composition, genetic alterations, and drug sensitivities.

cancer biology↗

bioRxiv2020

G9a Promotes Breast Cancer Recurrence Through Repression of a Pro-inflammatory Program

Epigenetic dysregulation is a common feature of cancer, and is thought to underlie many aspects of tumor progression. Using a genetically engineered mouse model of breast cancer recurrence, we show that recurrent mammary tumors undergo widespread epigenomic and transcriptional alterations, and acquire dependence on the G9a histone methyltransferase. Genetic ablation of G9a delays tumor recurrence, and pharmacologic inhibition of G9a slows the growth of recurrent tumors. Mechanistically, G9a activity is required to silence pro-inflammatory cytokines, including TNF, through H3K9 methylation at gene promoters. G9a inhibition induces re-expression of these cytokines, leading to p53 activation and necroptosis. Recurrent tumors upregulate receptor interacting protein kinase-3 (RIPK3) expression and are dependent upon RIPK3 activity. High RIPK3 expression renders recurrent tumors sensitive to necroptosis following G9a inhibition. These findings demonstrate that epigenetic rewiring - specifically G9a-mediated silencing of pro-necroptotic proteins - is a critical step in tumor recurrence and suggest that G9a is a targetable dependency in recurrent breast cancer.

cancer biology↗