Current Treatments and Gaps
The escalation in the incidence and mortality rates of cancer poses a formidable challenge to the global healthcare delivery system, with low- and middle-income countries (LMICs) bearing the brunt of the burden. These countries face a disproportionate challenge in accessing evidence-based cancer prevention, treatment, and palliative and survivorship care. A shortage of resources and infrastructure for high-quality cancer care further exacerbates the challenge (Mao et al., 2022). Cancer is a major cause of death worldwide. Traditional treatments include surgery, chemotherapy, and radiotherapy. However, recent years have seen the emergence of innovative therapies such as stem cell therapy, targeted therapy, ablation therapy, nanoparticles, natural antioxidants, radionics, chemodynamic therapy, sonodynamic therapy, and ferroptosis-based therapy. The focus is now on developing safe and efficient cancer nanomedicines to regenerate and repair damaged tissues. Targeted therapy holds significant breakthrough potential as it inhibits the growth and spread of specific cancer cells, causing less damage to healthy cells (Debela et al., 2021). However, Ensuring the long-term health of cancer survivors has emerged as a pivotal clinical imperative in the field of oncology. CAR-T cell engineering therapy has emerged as a promising modality for improving the clinical efficacy of both haematological malignancies and solid tumours. This innovative approach involves genetically modifying a patient's T cells to recognise and attack cancer cells. Despite its potential, however, CAR-T cell therapy has limitations that must be overcome to optimise its therapeutic benefit (Sterner and Sterner, 2021). In the past 25 years, antibody therapeutics have had over 100 FDA approvals and $100 billion in annual sales globally. Approximately half of the antibody therapeutics currently marketed are used in oncology (Goydel and Rader, 2021). However, a significant proportion of patients, approximately one-third, experience relapse (Ribas and Wolchok, 2018).
Extracellular vesicles (EVs) are small, lipid bilayer-delimited structures produced by almost all cell types. These structures are between 50 nm to 5 µm in size and are unable to replicate. Although initially believed to be a means of cellular waste removal, it is now understood that EVs have a range of biological functions, particularly in intercellular communication. They carry a variety of cargoes, including mRNA, non-coding RNAs (such as microRNA and long non-coding RNA), lipids, proteins, and metabolites. The contents of EVs are influenced by the health, state, and lineage of the parent cell (Rupaimoole and Slack, 2017, Kalluri and LeBleu, 2020). The new advanced treatment for cancer is mesenchymal stem cells exosomes. Cord blood stem cell-derived exosomes contain microRNAs that can target specific mRNAs, making them a promising candidate for treating various diseases. Exosomes obtained from human embryonic stem cells can facilitate reprogramming hematopoietic stem/progenitor cells and suppress oncogenic phenotypes of cancer cells (Lykke-Andersen et al., 2009, Zhang et al., 2017) and have the capability to exhibit different biological functions on recipient cells via the trafficking of different factors (i.e. nucleic acids, proteins, lipids)(Ratajczak et al., 2012, Zaborowski et al., 2015).
Dysregulated miRNAs in cancer can be classified as oncogenes or tumour suppressors. The tumour suppressor miRNAs are downregulated in malignant cells, leading to overexpression of their target oncogenes (Hart et al., 2020).
MicroRNAs (miRNAs) are non-coding RNAs that regulate gene expression. They interact with target mRNAs, leading to mRNA degradation and translational repression. MiRNAs can activate translation or regulate transcription and can be transported to target cells via vesicles or proteins (O'Brien et al., 2018). The miRNA machinery plays an essential role in the development and response of the immune system. Loss or degradation of certain individual miRNAs or the miRNA machinery can severely compromise immune development and response, leading to immune disorders. To maintain immune homeostasis, sophisticated regulatory mechanisms are employed. Among these mechanisms, Regulatory T (Treg) cells are essential for maintaining peripheral tolerance, preventing autoimmune diseases, and limiting chronic inflammatory diseases. These cells act as immune system suppressors, preventing the immune system's overactivation and keeping it in check (Ha, 2011). The extracellular vesicles (EVs) derived from cord blood stem cells (CBSCs) are nanosised vesicles that encapsulate diverse biomolecules, including miRNAs, proteins, lipids, and various other particles acting as cargo. The results of our previous research revealed that CBSC-derived exosomes have a significant cytotoxic effect on CHL1 malignant melanoma cells while showing no cytotoxicity on healthy cells. This finding provides insight into the potential of CBSC-derived exosomes as a therapeutic agent for malignant melanoma (Naeem et al., 2023)(
Figure 1). The exosomes of CBSC were subject to two different sets of studies, with the outcomes of both RNA analysis and RNA sequencing. While five of the listed miRNAs were well-known, two were novel (Naeem et al., 2023).
The treatment design for the present study is illustrated in Figure 2. The experimental groups were designed such that one group was treated with exosomes that down-regulated the newly discovered miRNAs, while another group was treated with CBSC-EVs. The treated cells were assessed using various assays including Comet assay to quantify the level of DNA damage, CCK8 to assay cell viability, and RNA sequencing to determine transcript isoforms, gene fusions, single nucleotide variants, and other features without the requirement of any prior knowledge.