Biology subjects

Sanai, N.

Publications and source records attributed to Sanai, N..

4 recordsLinked to original sources

bioRxiv2026

Combined HDAC and ATM inhibition with radiation in preclinical glioblastoma models

Background: Brain-penetrant histone deacetylase inhibitors (HDACi) are promising radiosensitizing agents for glioblastoma (GBM). HDAC inhibitors can impair DNA damage response (DDR) pathways and promote persistent DNA damage. Here, we evaluated whether combined inhibition of HDAC and the DNA repair kinase, ataxia-telangiectasia mutated (ATM), could synergize with radiation (IR) and improve therapeutic efficacy in GBM. Methods: In vitro dose-response assays were performed in patient-derived xenograft (PDX)-derived glioma stem cells (GSCs) with both inhibitors of HDAC (quisinostat, QST) and ATM (AZD1390) with or without IR treatment to assess synergy. Pharmacodynamic responses were evaluated by immunoblotting for histone acetylation, DDR signaling, and DNA damage markers. Transcriptomic analyses were performed to evaluate treatment-associated changes in DNA repair pathways. The combination of QST, AZD1390, and IR was further evaluated in an orthotopic GBM survival study. Results: Combined treatment with QST and AZD1390 produced synergistic radiosensitization in multiple GSC models in vitro. Furthermore, QST combined with IR suppressed transcription of homologous recombination (HR) pathway genes in GSCs, impairing double-strand break repair capacity through an epigenetic mechanism that does not directly inhibit ATM kinase activity. Pharmacodynamic analyses confirmed that QST increased histone acetylation while AZD1390 suppressed ATM signaling, together impairing complementary mechanisms to increase radiosensitivity of GSCs. In an orthotopic GBM model, QST combined with IR significantly prolonged survival compared with IR alone. However, the addition of AZD1390 did not provide a significant survival benefit beyond QST+IR, and AZD1390 combined with IR did not significantly improve survival relative to IR alone. Conclusions: Combined HDAC and ATM inhibition with QST and AZD1390 enhances radiosensitivity in patient-derived GBM cells, mechanistically underpinned by QST-mediated increase in DNA damage and dual disruption of DDR through complementary, non-overlapping mechanisms. However, this in vitro synergy did not confer additional survival benefit beyond QST+IR in an orthotopic GBM model under the dosing conditions tested, suggesting pharmacological limitations with the tumor microenvironment or suboptimal dosing schedules may have constrained in vivo efficacy.

cancer biology↗

bioRxiv2022

Quisinostat is a brain-penetrant radiosensitizer in glioblastoma

In recent years, histone deacetylase inhibitors (HDACi) have garnered considerable interest for the treatment of adult and pediatric malignant brain tumors. However, owing to their broad-spectrum nature and inability to effectively penetrate the blood-brain barrier, HDACi have failed to provide significant clinical benefit to glioblastoma (GBM) patients to date. Moreover, global inhibition of HDACs results in widespread toxicity, highlighting the need for selective isoform targeting. While no isoform-specific HDACi are currently available, the second-generation hydroxamic acid-based HDACi quisinostat possesses sub-nanomolar specificity for class I HDAC isoforms, particularly HDAC1 and 2. Recently, we demonstrated that HDAC1 is the essential HDAC in GBM. Here, we provide the first report on the neuro-pharmacokinetic, pharmacodynamic and radiation-sensitizing properties of quisinostat in preclinical models of GBM. We demonstrate that quisinostat is a well-tolerated and brain-penetrant molecule that significantly extends survival when administered in combination with radiation in vivo. The pharmacokinetic-pharmacodynamic-efficacy relationship was established by correlating free drug concentrations and evidence of target modulation in the brain with survival benefit. Together, these data provide a strong rationale for clinical development of quisinostat as a radiosensitizer for the treatment of GBM.

cancer biology↗

bioRxiv2020

Enhanced tissue penetration of antibodies through pressurized immunohistochemistry

To address the inefficiency of passive diffusion for antibody penetration in thick tissue samples, which limits clearing-technique applications, we developed a versatile and simple device to perform antibody incubation under increased barometric pressure. Pressurized immunohistochemistry greatly improves the uniformity, intensity, and depth of fluorescent immunostaining in thick human and mouse brain samples. Furthermore, pressurized immunohistochemistry substantially decreases the time required for classic staining of thin sections. SUBMISSION CATEGORYNew Results

molecular biology↗

bioRxiv2019

Probing glioblastoma and its microenvironment using single-nucleus and single-cell sequencing

Single-cell (scSeq) and single-nucleus sequencing (snSeq) are powerful tools to investigate cancer genomics at single cell resolution. Multiple studies have recently illuminated intratumoral heterogeneity in glioblastoma, however, the majority focused on molecular complexity of tumor cells, without considering unexplored host cell types that contribute to the microenvironment around tumor. To address the glioblastoma microenvironment composition and potential tumor-host interactions, we performed deep coverage sequencing of freshly resected primary GBM patient tissue without implementing any tumor enrichment strategies. The sequencing resulted in 902 cells and 1186 nuclei, respectively, passing quality control and with low mitochondrial gene percentage. We customized reference transcriptome by listing gene transcript loci as exons to take into account immature RNA, which greatly improved the alignment rate for single-nucleus data. We applied Cell Ranger pipelines (Version 3.0.2) and Seurat package (Version 2.3.1) and discovered 10 clusters in both scSeq and snSeq. Pathway analysis of each cluster signature in scSeq data along with known GBM microenvironment cell signatures revealed glioma tumor population along with surrounding microglia/macrophages, astrocytes, pericytes, oligodendrocytes, T cells and endothelial cells. The analysis of snSeq was able to capture the majority of cell types from patient tissues (tumor and microenvironment cells), but interestingly presented different cell type composition in microenvironment cell types such as microglia/macrophages. Integrating single-cell and single-nucleus transcriptomic data using canonical correlation analysis facilitated a comparison of snSeq and scSeq, contrasting depiction for certain cell types (e.g. NKX6-2 gene in Oligodendrocytes). Differential analysis of pathways between tumor and microenvironment cells unveiled potentially rewired pathways such as double strand break repair pathway. Our results demonstrate the cellular diversity of brain tumor microenvironment and lay a foundation to further investigate the individual tumor and host cell transcriptomes that are influenced not only by their cell identity but also by their interaction with surrounding microenvironment.

genomics↗