Biology subjects

Muley, A.

Publications and source records attributed to Muley, A..

4 recordsLinked to original sources

bioRxiv2025

Targeting Glioblastoma Cell State Plasticity for Enhanced Therapeutic Efficacy

Glioblastoma (GBM) is the most common and deadly primary brain cancer, with limited therapeutic options. Treatment failure has been associated with intratumoral heterogeneity and the acquisition of a pronounced mesenchymal-like (MES-L) phenotype after recurrence. Here, we have screened a panel of drugs with diverse mechanisms of action across two patient-derived glioblastoma stem cells (GSCs) to characterize the dynamics of drug-mediated transcriptomic cellular state changes. Our results demonstrate that anti-tumor drugs induce significant but reversible alterations in cellular state distribution at the single-cell level in a drug-specific manner, influencing transitions between mesenchymal and the neurodevelopmental astrocytic-like (AC-L) states. Utilizing barcoded analysis in our recently developed ex vivo glioblastoma cerebral organoid (GLICO) model, we discerned distinct cell state sensitivities to the MES-L enhancing histone deacetylase inhibitor, panobinostat, which are contingent on the inducible modulation of the mesenchymal transcription factor FOSL1. The strategic combination of MES-L enhancing and MES-l suppressing genetic perturbations or drugs significantly increases anti-glioma activity in a strategy we call state-selective lethality. Overall, our findings highlight the critical role of cell state plasticity in the response of GSCs to anti-tumor therapeutic stress and underscore the potential for novel GBM combination drug strategies.

cancer biology↗

bioRxiv2024

Roles for RERE in lymphatic endothelial cell proliferation and survival, and human cystic lymphatic malformations

Human congenital lymphatic anomalies (LAs) arise due to defects in lymphatic development. During a genetic study of fetuses with LAs, we identified a heterozygous pathogenic truncating variant in RERE in a fetus with a cystic lymphatic malformation (CLM). RERE is a transcriptional regulator which interacts with several key lymphangiogenic factors, including Notch and Coup-TFII. RERE also modulates retinoic acid signaling, which is essential for lymphatic vascular development. Thus, we hypothesized that RERE functions in lymphatic endothelial cells (LECs) and its loss contributes to LEC dysfunction and CLM pathogenesis. RERE was found to be expressed in the lymphatic endothelium during human development. RERE knockdown in human LECs reduced proliferation and induced apoptosis, increased expression of key lymphangiogenic genes, PROX1, COUP-TFII and VEGFR3, and altered expression of Notch target genes. RERE expression was elevated in LECs isolated from CLMs with pathogenic PIK3CA variants. These findings support a novel role for RERE in LECs, where RERE regulates LEC proliferation, LEC survival, lymphangiogenic gene expression and Notch signaling, which in turn suggests its loss contributes to CLM pathogenesis.

cell biology↗

bioRxiv2021

Unique functions for Notch4 in murine embryonic lymphangiogenesis

In mice, embryonic dermal lymphatic development is well-understood and used to study gene functions in lymphangiogenesis. Notch signaling is an evolutionarily conserved pathway that modulates cell fate decisions, which has been shown to both inhibit and promote dermal lymphangiogenesis. Here, we demonstrate distinct roles for Notch4 signaling versus canonical Notch signaling in embryonic dermal lymphangiogenesis. Actively growing embryonic dermal lymphatics expressed NOTCH1, NOTCH4 and DLL4 which correlated with Notch activity. In lymphatic endothelial cells (LECs), DLL4 activation of Notch induced a subset of Notch effectors and lymphatic genes, which were distinctly regulated by Notch1 and Notch4 activation. Treatment of LECs with VEGF-A or VEGF-C upregulated Dll4 transcripts, and differentially and temporally regulated the expression of Notch1 and Hes/Hey genes. Mice nullizygous for Notch4 had an increase in the closure of the lymphangiogenic fronts which correlated with reduced vessel caliber in the maturing lymphatic plexus at E14.5, and reduced branching at E16.5. Activation of Notch4 suppressed LEC migration in a wounding assay significantly more than Notch1, suggesting a dominant role for Notch4 in regulating LEC migration. Unlike Notch4 nulls, inhibition of canonical Notch signaling by expressing a dominant negative form of MAML1 (DNMAML) in Prox1+ LECs led to increased lymphatic density consistent with an increased in LEC proliferation, described for the loss of LEC Notch1. Moreover, loss of Notch4 did not affect LEC canonical Notch signaling. Thus, we propose that Notch4 signaling and canonical Notch signaling have distinct functions in the coordination of embryonic dermal lymphangiogenesis.

developmental biology↗

bioRxiv2020

p53 plays a central role in lymphatic anomalies

Activation of the transcription factor p53 has been associated with several developmental syndromes. In normal tissues, p53 is kept at very low undetectable physiological levels. When triggered by cellular stressors, p53 prompts important anti-proliferative and apoptotic programs part of its tumor suppressor activity or as the guardian of tissue homeostasis. We generated two murine models that display cutaneous hemorrhaging, severe edema, and distended blood-filled lymphatic vessels at late-gestation due to overactive p53 uniquely affecting lymphatic endothelial cells during development. Overactive p53 operated distinctively through anti-proliferative route in this tissue resulting in a decrease in initial lymphatics that normally absorb interstitial fluid. Remarkably, genetic or pharmacologic normalization of p53 restored lymphatic homeostasis and reversed lymphatic phenotypes. In parallel, several human lymphatic disease tissues exhibited high p53 levels exclusively in the lymphatic endothelium while p53 remained undetectable in surrounding arterial or venous vessels. We report here, for the first time, an extended role that the p53 pathway plays in the genesis of lymphatic homeostasis deficiencies opening the way for new therapeutic avenues for these rare, poorly understood, and incurable lymphatic maladies.

developmental biology↗