DDDR-30. ENHANCED CHEMO AND RADIO-SENSITIZATION OF GLIOMAS BY HSP90 INHIBITION WITH JIN-001, A NOVEL BLOOD-BRAIN BARRIER PENETRANT HSP90 INHIBITOR

Abstract BACKGROUND HSP90, an abundant molecular chaperone, plays a pivotal role as a key regulator in the growth and survival of malignant cells and has been a therapeutic target in various cancers. We have previously reported a strong role for HSP90 inhibitors to disable DNA damage repair mechanisms and induce cell death. Here, we determined the effects of JIN-001 mediated HSP90 inhibition on alkylator and radiation induced DNA damage. Method: Using a panel of patient-derived glioma stem cells (GSCs) we determined the synergy scores for cell viability of JIN-001 (0.1µM to 0.5µM) in combination with radiation (RT) and Temozolomide (TMZ). We also examined cell cycle dynamics and cell death of the combination using flow cytometry (PI and PI/Annexin method) and cell viability assays. Additionally, organotypic human glioma slice cultures treated with JIN-001 and chemoradiation were analyzed for changes in gene and protein expression as well as cell viability in situ. Ongoing in-vivo studies are being conducted to further elucidate drug combination efficacy in mouse models. RESULTS JIN-001 sensitized the cells to chemoradiation leading to cell cycle arrest and cell death which was higher in the combination compared to single agent. Significant changes in expression of downstream molecules of homologous recombination pathway was noted (ATM, pATM, CHK1, pCHK1, ATR, pATR) in the cell lines and confirmed in human glioma slice culture. Based on the synergy score from four cell lines, an effective dose for combination of JIN-001+RT+TMZ was identified; Results of ongoing ex-vivo human glioma gene expression changes and in-vivo mouse studies will be presented. CONCLUSION Through a comprehensive analysis, we demonstrated that HSP90 inhibitor JIN-001 sensitizes glioma cells to radio-chemotherapy including in human glioma tissue. Our study underscores the potential of combining JIN-001 with standard therapies in glioma treatment in future clinical trials for patients with glioblastoma.