Autophagy Flux Blockade Alters Cholesterol Metabolism and Sustains Temozolomide Resistance in Glioblastoma

Autophagy Flux Blockade Alters Cholesterol Metabolism and Sustains Temozolomide Resistance in Glioblastoma | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Autophagy Flux Blockade Alters Cholesterol Metabolism and Sustains Temozolomide Resistance in Glioblastoma Saeid Ghavami, Shahla Shojaei, Amir Barzegar Behrooz, Kianoosh Naghibzadeh, and 23 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9099402/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Temozolomide (TMZ) resistance remains a major barrier to effective glioblastoma therapy and is increasingly linked to metabolic adaptation and cellular stress responses. In this study, we investigated the relationship between autophagy dysregulation and cholesterol metabolism during glioma progression and TMZ resistance. Tissue microarray analysis of astrocytoma and glioblastoma specimens demonstrated progressive accumulation of LC3β puncta together with increased FDPS expression, suggesting coordinated alterations in autophagy and cholesterol metabolism in high-grade tumors. To explore this relationship mechanistically, TMZ-resistant U251 glioblastoma cells were generated and compared with TMZ-sensitive counterparts. Resistant cells exhibited epithelial-to-mesenchymal transition–like morphology, reduced proliferation, mitotic quiescence, mitochondrial remodeling, and diminished respiratory reserve capacity, consistent with a therapy-tolerant metabolic phenotype. Ultrastructural and biochemical analyses revealed persistent autophagosome accumulation and impaired autophagy flux in resistant cells. This defect was accompanied by suppression of de novo cholesterol biosynthesis, reduced expression of SREBP2 and LDLR, and extensive remodeling of cholesterol ester species identified by lipidomic profiling. Although inhibition of the mevalonate pathway with simvastatin altered cholesterol ester composition, it failed to restore TMZ sensitivity or induce apoptosis in resistant cells. Together, these findings indicate that persistent autophagy flux impairment and altered cholesterol metabolism characterize TMZ-resistant glioblastoma. Biological sciences/Cell biology/Autophagy/Macroautophagy Biological sciences/Cancer/Cancer therapy/Cancer therapeutic resistance Temozolomide resistance Autophagy flux blockade Cholesterol metabolism Cholesteryl esters Metabolic plasticity Full Text Additional Declarations There is no conflict of interest Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9099402","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":611798395,"identity":"64210376-deff-4cd2-a8d8-1791601115f0","order_by":0,"name":"Saeid 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