The Blood-Brain/Tumor Barriers: Challenges and Chances for Malignant Gliomas Targeted Drug Delivery

Treatment of malignant gliomas remains a challenge irrespective of the recent improvements. Chemotherapeutic agents for malignant gliomas have been particularly inefficient for the existence of blood-tumor barrier (BTB), which hampers the accumulation and uptake in tumor. Moreover, even though blood-brain barrier (BBB) is compromised to some extent under the situation of malignant gliomas, it remains to be the obstacle influencing the therapeutic efficacies via systemic administration. Fortunately, there are many receptors over-expressed on the BTB (glioma cells and/or tumor microvessels) that can mediate ligand modified drug delivery systems targeting to gliomas and enhance tumor uptake. On the other hand, numerous routes have also been explored to circumvent the BBB. In this manuscript, we elucidate the BBB/BTB status under the situation of malignant gliomas and review the receptors over-expressed on BTB and the malignant gliomas targeted drug delivery strategies. We also discuss the perspective of malignant gliomas targeted drug delivery systems with new concepts.