DDDR-14. DEVELOPMENT OF A NOVEL CYP17A1-TARGETED INHIBITOR FOR GLIOBLASTOMA

Abstract

Abstract Glioblastoma (GBM) is a highly aggressive and invasive brain tumor, resistant to current standard treatments, including temozolomide (TMZ) and radiotherapy. Despite these interventions, GBM's intrinsic drug resistance often renders it incurable, thus highlighting the dire need for novel therapeutic strategies. In this study, we used ultra-high pressure liquid chromatography-mass spectrometry to examine the levels of neurosteroids in tumor specimens from primary and recurrent GBM patients. This led to the discovery of differential expression patterns, most notably in androgen, including dehydroepiandrosterone and testosterone. Our results indicated androgen over-production weakens the GBM's sensitivity to TMZ by inducing post-translational modification of Sp1 protein, which aids in DNA repair. Interestingly, Sp1 activity is further enhanced by histone deacetylase (HDAC) 6, which in turn diminishes the DNA damage caused by TMZ. In addition, proteomic analysis revealed an overexpression of cytochrome (CYP) 17A1, particularly in recurrent GBM, which led us to hypothesize that a drug inhibiting both CYP17A1 and HDAC6 could potentially serve as a viable treatment for TMZ-resistant GBM. To validate this, the drug was tested in vitro on U87MG-R cells and patient-derived Pt#3 TMZ-resistant cells, demonstrating the therapeutic efficacy based on cell viability assays. In vivo testing in the TMZ-resistant GBM orthotopic mouse model also showed promising anti-tumor activity, with treated mice demonstrating increased survival times compared to controls. In conclusion, our findings suggest that this drug targeting both CYP17A1 and HDAC6 presents a potential breakthrough in GBM-targeted therapy, addressing the pervasive issue of TMZ resistance.