Applications of Melanin and Melanin-Like Nanoparticles in Cancer Therapy: A Review of Recent Advances

Abstract

Thanks to the growing knowledge about cancers and their interactions with the immune system, a huge number of therapeutic cancer vaccines have been developed in the past two decades. Despite encouraging results in pre-clinical models, cancer vaccines have not yet achieved significant clinical efficacy. Several factors may contribute to such poor results, including the difficulty of triggering a strong immune response and the immunosuppressive tumor microenvironment. Many strategies are currently being explored. Different types of adjuvants have been incorporated into vaccine formulations to improve their efficacy, as cancer antigens are usually poorly immunogenic. Nanoparticle systems are promising tools as they act as carriers for antigens and can be surface-modified so that they specifically target antigen-presenting cells in lymph nodes. Bioinspired nanomaterials are ideal candidates thanks to their biocompatibility. Recently, melanin-based nanoparticles were reported to efficiently localize into draining lymphoid tissues and trigger immune responses against loaded antigens. In addition, by virtue of their photochemical properties, melanin-based nanoparticles can also play an immunomodulatory role to promote anti-cancer responses in the context of photothermal therapy. In this review, we discuss the above-mentioned properties of melanin, and summarize the promising results of the melanin-based cancer vaccines recently reported in preclinical models.

Raman Characterization of Fungal DHN and DOPA Melanin Biosynthesis Pathways

“…Melanin has gained increased attention in recent years due to its many applications in dermocosmetics [ 5 , 6 , 7 , 8 ], dyeing [ 2 , 5 , 9 , 10 , 11 ], environmental remediation [ 5 , 12 , 13 ], materials science [ 6 , 14 , 15 , 16 , 17 ], nanotechnology [ 6 ], and biomedicine [ 5 , 18 , 19 , 20 , 21 , 22 , 23 ]. Significantly, there is increased interest in using melanin in cancer therapy, in which it can function in multiple roles [ 23 ].…”

“…Melanin has gained increased attention in recent years due to its many applications in dermocosmetics [ 5 , 6 , 7 , 8 ], dyeing [ 2 , 5 , 9 , 10 , 11 ], environmental remediation [ 5 , 12 , 13 ], materials science [ 6 , 14 , 15 , 16 , 17 ], nanotechnology [ 6 ], and biomedicine [ 5 , 18 , 19 , 20 , 21 , 22 , 23 ]. Significantly, there is increased interest in using melanin in cancer therapy, in which it can function in multiple roles [ 23 ]. However, “a better knowledge of the physicochemical properties of the different melanins along with a better understanding of the mechanisms behind anti-cancer activity for each type of melanin is required to optimize the applications of melanin in cancer therapy” [ 23 ].…”

“…Significantly, there is increased interest in using melanin in cancer therapy, in which it can function in multiple roles [ 23 ]. However, “a better knowledge of the physicochemical properties of the different melanins along with a better understanding of the mechanisms behind anti-cancer activity for each type of melanin is required to optimize the applications of melanin in cancer therapy” [ 23 ].…”

In Vitro Insights Regarding the Role of Melanin in Melanoma Cells’ Response to Betulinic Acid Treatment

“…Melanin is known as a photoprotector against UVR-induced damage by reducing the skin penetration of UV light and counteracting harmful ROS [10,11]. It also possesses a potent chelating property, being able to bind pharmacologically active compounds via both covalent and non-covalent bonding, due to its abundance in functional groups such as oquinone, amine, catechol and imine [12], ability which might influence the efficiency of MM treatment. Current MM treatment strategies resort to surgery, chemotherapy, targeted therapy and immunotherapy.…”

NIR-Mediated Drug Release and Tumor Theranostics Using Melanin-Loaded Liposomes

“…In particular, melanin can absorb light of all wavelengths, especially near-infrared rays, thus generating heat effectively [9]. Many attempts have been made to utilize melanin in biomedical elds including PTT [10][11][12]. Recently, bubble-generating nanoparticles above speci c temperature have been proposed to control drug release and provide ultrasound imaging [13][14][15].…”