Protein and Peptide Letters - Online First

Messenger RNA (mRNA) has gained increasing attention as a valuable tool to cure various human diseases, particularly malignant tumors. Such growing interest has been triggered largely by the phenomenal clinical success of mRNA vaccines developed using lipid nanoparticle (LNP) technology against COVID-19. mRNA may be used to produce cancer immunotherapies in numerous different ways, including cancer vaccines to induce or enhance immunity to tumor-specific antigens (TSAs) or tumor-associated antigens (TAAs). mRNA can also be used to adoptively transfer T-cells for the expression of antigen receptors, such as chimeric antigen receptors (CARs), therapeutic antibodies, and immunomodulatory proteins to re-engineer the tumor microenvironment. However, the therapeutic potential of mRNA-based cancer immunotherapy is not fully utilized due to a few limitations, such as mRNA instability, production of immunogenicity, and a lack of efficient in-vivo delivery methods. This review provides an overview of the current advancements and future directions of mRNA-based cancer therapies, including various delivery routes and therapeutic platforms. It addresses the mechanistic basis of mRNA cancer vaccines, non-replicating and self-amplifying mRNA, as well as their clinical development, personalized vaccines, and applications of mRNA for encoding antigen receptors, antibodies, and immunomodulatory proteins. Moreover, the review addresses nanoparticle-based platforms, such as lipid nanoparticles (LNPs), polymeric nanoparticles, and peptide-based nanoparticles, all used to improve the therapeutic effectiveness of mRNA-based drugs by improving their targeted delivery to tissues. This review aims to provide insights into the use of state-of-the-art mRNA-based cancer immunotherapy.

The natural horizon of the genetic code has expanded to incorporate amino acids, such as selenocysteine and pyrrolysine. Researchers have incorporated unnatural amino acids (UAAs) into target proteins, demonstrating increased protein functionality depending on their choice and target. The primary challenge in protein engineering is identifying novel antimicrobial short peptides effective against ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.), which are categorized as multidrug-resistant (MDR). UAAs can be preferentially incorporated into short peptides to display therapeutic activity, potentially leading to next-generation targeted therapeutics. In purview of this, we have curated and summarized the applicability of genetic incorporations of UAAs in antimicrobial short peptides with a special emphasis on the importance of green synthesis. The approach affirmed a reduction in the toxicity of peptide drugs, making it biocompatible. This is an efficient protocol to develop novel antimicrobial short peptides catering to precision medications, particularly against MDR pathogens, as a sustainable pharmaceutical approach.

The incidences of immune-related disorders have drastically increased in recent years across the world population. Treatment and management of these diseases, especially autoimmune disorders, are complex and challenging. Available synthetic drugs are not completely effective and also pose serious side effects for the patients. Cyclotides are a class of plant-derived cyclic peptides (28-37 amino acids) with three conserved disulfide linkages establishing a cyclic cystine knot (CCK) motif that makes them very stable biomolecules. Their inherent stability, bioavailability and membrane-penetrating capabilities render them attractive potential pharmacological agents. Studies have demonstrated that cyclotides can either enhance or suppress immune responses, making them versatile candidates for treating various immune-related disorders. Of more than 1000 cyclotides discovered to date, only up to 15 native cyclotides (e.g. kalata B1, pase and caripe cyclotides) have been screened to demonstrate their immunomodulatory activity. Of special significance is the chemically synthesised lysine mutant of kalata B1 viz. [T20K], where preclinical studies have shown promise in the treatment of the autoimmune disorder, multiple sclerosis. In vivo studies in mice models have demonstrated that daily administration of 1mg/day of [T20K] led to a significant decrease in the level of cytokine secretion, lesser demyelination (<1%) and very low inflammatory index (<0.5), in the immunized mice. Moreover, when compared with other immunosuppressive drugs (azathioprine, prednisolone, and cyclosporine A) there was a notable drop in mortality and morbidity in mice administered with [T20K]. The cyclotides, kalata B1 and MCoTI-I have also been used as scaffolds to graft bioactive peptides with immunomodulatory activity. Subsequent in vitro and in vivo studies of these grafted cyclotides have demonstrated their therapeutic ability. Keeping in view the therapeutic potential of cyclotides as immunomodulatory peptides, the present review discusses its current research scenario and implications for the future in tackling immune-related disorders.