Exosomal CeRNAs from the tumor microenvironment: hidden drivers of colorectal cancer progression

Colorectal cancer (CRC) remains a major global health burden, with rising incidence and mortality, particularly in developing countries. The tumor microenvironment (TME) plays a critical role in CRC progression by facilitating angiogenesis, immune evasion, and metastasis through complex intercellular communication. Among the key mediators of this communication are exosomes-nano-sized extracellular vesicles-that transport a variety of bioactive molecules, including competing endogenous RNAs (ceRNAs). These ceRNAs, such as long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and mRNAs, act as molecular sponges for microRNAs (miRNAs), thereby regulating gene expression and influencing cancer-related pathways like Wnt/β-catenin and PI3K/Akt. This review explores the emerging role of exosomal ceRNAs derived from the TME in CRC progression, emphasizing their involvement in promoting tumor cell proliferation, invasion, metastasis, and resistance to therapy. By elucidating the intricate crosstalk between exosomal ceRNAs and the TME, we highlight their potential as novel biomarkers and therapeutic targets, offering new avenues for personalized treatment strategies in colorectal malignancies. Despite growing interest in exosomes and non-coding RNAs in colorectal cancer (CRC), limited attention has been given to the specific role of exosomal ceRNAs derived from the tumor microenvironment (TME). Existing reviews have predominantly addressed broader aspects of exosomal non-coding RNAs (e.g., miRNAs, lncRNAs, and circRNAs in general CRC progression, metastasis, or as biomarkers) or focused on exosomal communication in other malignancies. However, the intricate mechanisms by which TME-derived exosomal ceRNAs establish regulatory networks to drive CRC pathology-particularly through miRNA sponging in stromal-tumor crosstalk-remain underexplored and insufficiently synthesized. This review addresses these critical gaps by uniquely emphasizing exosomal ceRNAs sourced from the TME (including CAFs, macrophages, and other stromal components), elucidating their convergent roles in orchestrating proliferation, invasion, immune evasion, and chemoresistance. By integrating recent evidence into a TME-centric framework, we provide novel insights into potential diagnostic and therapeutic applications, advancing beyond general exosomal RNA overviews toward targeted strategies for CRC.