Exosomes Based Geldanamycin Delivery to Cancer Cells with Increased Therapeutic Efficacy

HSP90 has been shown to promote oncogenic functions and cell proliferation during tumor progression. Geldanamycin is a potent inhibitor of HSP90, however therapeutic effects are often hampered due to its extreme hydrophobicity and systemic toxicity. Hence targeted delivery strategies are needed to overcome these limitations and to improve the efficacy of the drug. Here we utilize a novel geldanamycin delivery approach by utilizing exosomes. For the study, exosomes were extracted from cancer cells, loaded with geldanamycin, and the therapeutic effects were tested in cancer cells. Results show that cancer cells derived exosomes exhibit specificity to cancer cells. Further exosomes loaded geldanamycin show several fold increase in efficacy compared to free geldanamycin. Findings indicate exosomal formulations could be used for extremely hydrophobic HSP90 inhibitor geldanamycin delivery for inhibiting cancer cell proliferation.