Nanoimmunotherapy – cloaked defenders to breach the cancer fortress

Cancer continues to be ranked among the top causes of mortality in the world despite the advances made in science and technology. The sub-par performance of cancer therapeutic strategies is due to the transformation of the cancer from a proliferating mass of cells into an impregnable fortress that manipulates and controls the microenvironment to prevent access to any potential cytotoxic factor as well as circumvent the innate immune surveillance processes. Recruitment of the native immune cells to selectively recognize and kill cancer cells can serve to augment the cytotoxic effects of conventional cancer therapeutic approaches. In addition to annihilation of the cancer cells, the induction of memory in the immune cells prevents the possibility of cancer recurrence. However, despite the apparent benefits of cancer immunotherapy, there are several pitfalls that need to be addressed in order to extend these benefits to the clinic. In this context, engineered nanostructured carrier systems can be effectively employed for an activation and priming of the host immune system selectively against the target cancer cells. This has led to the emergence of “nanoimmunotherapy” as an important therapeutic approach against cancer. The use of multi-functional nanomaterials in combination with immunotherapy offers possible solutions to overcome the current limitations in cancer therapy and represents the next generation of “smart therapeutics,” which forms the prime focus of discussion in this review