PLGA-based dual-loaded nanoformulation of DIM and TMZ - An advanced clinical strategy for brain cancer treatment in a combinatorial approach

Glioblastoma multiforme (GBM) is a highly aggressive form of primary brain tumor in adults, which unfortunately has an abysmal prognosis and poor survival rates. Even though several FDA-approved multimodal treatments for targeting GBM are available, the effectiveness in most patients are not satisfactory. The reason behind this poor success rate is mainly attributed to insufficient drug distribution to the tumor site across the blood-brain barrier (BBB) and induction of resistance for single-drug based therapies. Chemotherapy with Temozolomide (TMZ) having a median overall survival of around 12-15 months, envisages the urgent necessity for more effective treatment strategies. Based upon these facts, in this study, we have developed a novel approach for repurposing TMZ along with inhibition of EGFR, which overexpressed in GBM, to achieve our goal. PLGA-based nanoencapsulation of both TMZ and 3,3-diindoyl methane (DIM), an EGFR inhibitor, in a combinatorial approach enhances the delivery of them together. Their synergistic mode of actions, significantly enhances the cytotoxic effect of TMZ in vitro and in vivo. Moreover, the dual-loaded nanoformulation works more efficiently than their individually packed nanoparticles on DNA damage and apoptosis, resulting in a several-fold reduction in tumor burden, systemic drug toxicity, and increased survival. These findings suggest the preclinical potential of this new treatment strategy.