Search bioRxivSearch

Biology subjects

Aguilar, B.

Publications and source records attributed to Aguilar, B..

2 recordsLinked to original sources

Patient-Derived Glioma Models Preserve Tumor Heterogeneity and Identify Stearoyl-CoA Desaturase1 (SCD1) as a Candidate Biomarker for Precision Immunotherapy

Background: Pediatric and adult brain tumors, including glioblastoma, astrocytoma, ependymoma, and medulloblastoma, remain associated with poor prognosis despite advances in surgery, radiation, and chemotherapy. Therapeutic resistance, tumor heterogeneity, and treatment-related toxicity highlight the need for clinically relevant models that enable precision medicine and immunotherapy development. Methods: Freshly dispersed tumors (FDTs), low-passage patient-derived brain tumor (PBT) spheroid lines, and matched patient-derived xenograft (PDX) models were established from patients with primary brain tumors. Models were characterized using single-cell and bulk RNA sequencing, whole-exome sequencing, multiparameter flow cytometry, and immunohistochemistry. PBTs were compared with matched FDTs to evaluate model fidelity. Results: PBT lines were established in approximately 68% of cases and retained key patient-specific genomic alterations, including IDH1, MGMT, TP53, and PTEN, with expression of therapeutically relevant targets, including IL13R2, EGFR, HER2, WNT1, JAK1/2, and NOTCH1-4. Gene expression profiles of PBTs closely correlated with matched FDTs (R = 0.38, P = 0.0038). PBT and PDX models preserved intratumoral heterogeneity and non-clonal populations, enabling identification of therapy-resistant subclones during in vitro selection. Molecular analyses identified Stearoyl-CoA Desaturase1 (SCD1) as an overexpressed biomarker across glioma PBTs and matched patient tumors. Ingenuity Pathway Analysis identified SCD1 as an upstream regulator of EGFR-, TP53-, and CYCS-associated signaling networks implicated in tumor progression and immune suppression. Conclusions: Clinically relevant PBT and matched PDX models recapitulate molecular, transcriptional, and histopathological characteristics of primary brain tumors. These platforms provide tools for biomarker discovery, therapeutic testing, and precision immunotherapy development, while identifying SCD1 as a biomarker and therapeutic target in glioma.

cancer biology

Selective axonal translation of prenylated Cdc42 mRNA isoform supports axon growth

The small Rho-family GTPase Cdc42 has long been known to have a role in cell motility and axon growth. The eukaryotic CDC42 gene is alternatively spliced to generate mRNAs with two different 3UTRs that encode proteins with distinct C-termini. The C-termini of these Cdc42 proteins include CAAX and CCAX motifs for post-translational prenylation and palmitoylation, respectively. Palmitoyl-Cdc42 protein was previously shown to contribute to dendrite maturation, while the prenyl-Cdc42 protein contributes to axon specification and its mRNA was detected in neurites. Here, we show that the mRNA encoding prenyl-Cdc42 isoform preferentially localizes into PNS axons and this localization selectively increases in vivo during PNS axon regeneration. Isoform specific siRNA knockdowns, rescue experiments with siRNA-resistant Cdc42 isoforms, and pharmacologically targeting Cdc42 activity indicate that prenyl-Cdc42 promotes axon growth while the palmitoyl-Cdc42 has little growth promoting activity. The growth promotion by prenyl-Cdc42 requires axonal mRNA localization with localized translation and an intact C-terminal CaaX motif for localized prenylation of the encoded protein. Together, these data show that alternative splicing of the CDC42 gene product generates an axon growth promoting locally synthesized prenyl-Cdc42 protein. SUMMARY STATEMENTAxon regeneration drives selective localization of alternatively spliced CDC42 isoform to PNS axons.

neuroscience