Approaches to Improve Efficiency of Dendritic Cell-based Therapy of High Grade Gliomas.

High grade gliomas (HGGs) are the most frequent and highly invasive type of brain tumors, which arise from glial cells. Among HGGs, glioblastoma multiforme (GBM) is the commonest and deadliest tumor type. Standard HGG therapy that involves tumor resection followed by concomitant treatment with radiation exposure and temozolomide (TMZ) cannot prevent recurrent tumor. The median survival of treated patients after surgery does not exceed 1.5 years. Vaccination with autologous dendritic cells (DCs) pulsed with tumor-specific peptides, antigens, or lysates is considered as a promising option to induce a potent anti-tumor immune response and cytotoxicity against GBM cells. However, since the tumor microenvironment is highly immunosuppressive and immunotolerant, specialized approaches should be applied to protect DC transplants against tumor-induced functional impairment and inhibition. So far, many phase I-III clinical trials utilizing DC vaccines for HGG treatment were completed or are underway. In summary, DC vaccination was safe and well tolerated by patients. DC-induced anti-tumor immune responses correlated with prolonged overall and progression- free survival. Combination of DC therapy with other interventional strategies (i.e., radiotherapy, chemotherapy, antibodies, etc.) and multimodal approaches should improve HGG treatment outcomes. In this review, we consider strategies that provide an option to override the immune inhibitory tumor microenvironment and boost DC vaccine-based antitumor immune response.