Editorial: Non-coding RNAs in Breast Cancer -Volume II

Wenwen Zhang ^1* Naoyuki Kataoka ² Xiaoxiang Guan ³

• ¹ Nanjing First Hospital, Nanjing Medical University, Nanjing, China
• ² The University of Tokyo, Bunkyo, Tōkyō, Japan
• ³ Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China

Non-coding RNAs in Breast Cancer -Volume II Non-coding RNAs (ncRNAs) represent a category of RNA that do not possess protein-coding capabilities, encompassing microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Despite their inability to encode proteins, ncRNAs play a crucial role in modulating the expression of various molecular targets, thereby influencing specific cellular biological processes and outcomes. To date, numerous ncRNAs have been identified and shown to be dysregulated across various cancer types, including breast cancer (1). Furthermore, the potential of ncRNAs as diagnostic and prognostic biomarkers, as well as therapeutic targets, has been thoroughly investigated in breast cancer (1,2). This research topic collected 12 articles (four original research studies, and eight reviews), which concentrated on novel discoveries or assessed recent advancements of ncRNAs in breast cancer.Firstly, a comprehensive review by Li et al. highlights the promise of two significant classes of non-coding RNAs, namely lncRNAs and miRNAs, as both diagnostic and prognostic biomarkers for breast cancer, as well as potential targets for innovative therapeutic approaches. Chen et al. conducted a comprehensive review on the substantial impact of lncRNAs on the progression, diagnosis, and effectiveness of neoadjuvant chemotherapy in triple-negative breast cancer (TNBC), highlighting the varied expression profiles of dysregulated lncRNAs. They provided a summary of the precise mechanisms through which lncRNAs modulate gene expression in both the nucleus and cytoplasm, influencing post-transcriptional processes that affect mRNA stability and translation efficiency, thereby regulating tumor cell growth, proliferation, and metastasis.ncRNAs have been reported to be involved in the regulation of signaling pathways for a variety of molecules or genes (3). 2-Methoxyestradiol (2ME2) is the primary endogenous metabolite of 17β-estradiol. It exhibits a diminished affinity for the estrogen receptor compared to 17β-estradiol and its derivatives, and its mechanism of action operates independently of the cellular response to estrogen (4). Subramani et al. found 2ME2 modifies the expression of pertinent genes by influencing the miRNome in TNBC cells, subsequently inhibiting TNBC through its impact on critical processes such as cell proliferation, apoptosis, and metastasis. Pyruvate kinase M2 (PKM2) serves as a crucial metabolic enzyme within the glycolytic pathway (5) Investigating SNPs elucidates the variations in individual predisposition to diseases, disparities in pharmacological responses, and differences in reactions to environmental stimuli (8). The findings of Qi et al. confirmed that specific LncRNA H19 gene polymorphisms are linked to an increased susceptibility to breast cancer, and that the expression levels of associated genetic markers can profoundly influence the prognosis and therapeutic response in patients with breast cancer. circRNAs are extensively investigated for their role as molecular sponges for miRNAs, which compete for binding to miRNA-targeted messenger RNAs (9). This interaction contributes to the establishment of a sophisticated post-transcriptional regulatory framework known as the competitive endogenous RNA (ceRNA) network (9). In this research topic, Liu et al. found EIF4A3 could enhance the expression of circ_0022382, and elevated levels of circ_0022382 may activate the PI3K/AKT/mTOR signaling pathway and SLC7A11 by sequestering let-7a-5p. Conversely, the silencing of circ_0022382 can impede the proliferation and migration of breast cancer cells, while also promoting the onset of disulfidptosis in breast cancer.Exosomes represent a category of extracellular vesicles encased in a lipid bilayer, lacking intracellular organelles yet encompassing all known molecular components found within a cell. Tumor cells release exosomes approximately ten times greater than that of normal cells (10). These tumor-derived exosomes play a crucial role in mediating intercellular communication and are implicated in various phases of cancer progression (10). Primary breast tumor cells have been shown to sensitize brain microenvironmental cells, facilitating the development of breast cancer brain metastasis (BCBM) via the secretion of extracellular vesicle-associated miRNAs (11). miRNAs originating from breast tumors can also enhance the invasion of breast cancer cells across the blood-brain barrier by compromising the integrity of brain microvascular endothelial cells (11). Khan et al.provided a comprehensive review of the current literature on miRNAs derived from breast cancer that promote BCBM, detailing their roles in the intricate processes of BCBM, their