Revolutionizing cancer therapy: nanoformulation of miRNA-34 – enhancing delivery and efficacy for various cancer immunotherapies: a review

Despite recent advancements in cancer therapies, challenges such as severe toxic effects, non-selective targeting, resistance to chemotherapy and radiotherapy, and recurrence of metastatic tumors persist. Consequently, there has been considerable effort to explore innovative anticancer compounds, particularly in immunotherapy, which offer the potential for enhanced biosafety and efficacy in cancer prevention and treatment. One such avenue of exploration involves the miRNA-34 (miR-34) family, known for its ability to inhibit tumorigenesis across various cancers. Dysregulation of miR-34 has been observed in several human cancers, and it is recognized as a tumor suppressor microRNA due to its synergistic interaction with the well-established tumor suppressor p53. However, challenges have arisen with the therapeutic application of miR-34a. These include its susceptibility to degradation by RNase in serum, limiting its ability to penetrate capillary endothelium and reach target cells, as well as reports of immunoreactive adverse reactions. Furthermore, unexpected side effects may occur, such as the accumulation of therapeutic miRNAs in healthy tissues due to interactions with serum proteins on nano-vector surfaces, nanoparticle breakdown in the bloodstream due to shearing stress, and unsuccessful extravasation of nanocarriers to target cells owing to interstitial fluid pressure. Despite these challenges, miR-34a remains a promising candidate for cancer therapy, and other members of the miR-34 family have also shown potential in inhibiting tumor cell proliferation. While the in vivo applications of miR-34b/c are limited, they warrant further exploration for oncotherapy. Recently, procedures utilizing nanoparticles have been developed to address the challenges associated with the clinical use of miR-34, demonstrating efficacy both in vitro and in vivo. This review highlights emerging trends in nanodelivery systems for miR-34 targeting cancer cells, offering insights into novel nanoformulations designed to enhance the anticancer therapeutic activity and targeting precision of miR-34. As far as current knowledge extends, no similar recent review comprehensively addresses the diverse nanoformulations aimed at optimizing the therapeutic potential of miR-34 in anticancer strategies.