The Role and Application of Exosomes in Gastric and Colorectal Cancer

Exosome-mediated Transfer of lncRNA in Liver Associated Diseases; Uncovered Truths

Exosomes are extracellular vesicles with a diameter ranging from 40 to 160 nm. They are produced by hepatocytes, cholangiocytes, hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs) and Kupffer cells in liver tissue. The secretion of exosomes might vary in quantity and composition in reaction to multiple triggers and various stages of disease. They transport various payloads, such as proteins, DNAs, and RNAs, and enable cell interaction to regulate myriad physiological and pathological processes in liver tissue. Long non-coding RNAs (lncRNAs) are a crucial component of exosomes with an excellent capability to regulate multiple cellular activities such as differentiation, development, metabolism, proliferation, apoptosis, and activation. With the advancements in transcriptomic and genomic study methods and database management technology, the functions and mechanisms of exosomal lncRNAs in liver diseases have been well-studied. This article delves into the detailed role of exosomal lncRNAs in liver disease onset and progression, ranging from hepatocellular carcinoma (HCC) to liver fibrosis drug-induced liver damage (DILI) and steatotic liver diseases.

Functions and Clinical Applications of Exosomes in Gastric Cancer

Gastric cancer is a common and highly invasive type of malignant tumor, the pathogenesis of which remains unclarified. However, exosomes are now known to play important roles in gastric cancer development and treatment. Cells use exosomes for the packaging and transportation of a variety of bioactive molecules, such as proteins, double-stranded DNA, and micro-ribonucleic acids, to other sites. Exosome-specific membrane structures and exosomal contents are widely involved in processes that facilitate material exchange and intercellular communication between gastric cancer cells. They help in forming a pre-metastatic microenvironment, promoting the proliferation and apoptosis of gastric cancer cells, and driving invasion, metastasis, and resistance to anti-tumor drugs. In this review, we aimed to summarize the findings of research articles indexed in the PubMed, Web of Science, and Embase databases and published up to May 31, 2024, on the role of exosomes in the pathogenesis of gastric cancer and their potential clinical applications in its treatment. Thus, research on exosomes may lead to breakthroughs in the early diagnosis of gastric cancer and identification of novel treatments.

Advancements in non-invasive diagnosis of gastric cancer

Gastric cancer (GC), a multifaceted and highly aggressive malignancy, represents challenging healthcare burdens globally, with a high incidence and mortality rate. Although endoscopy, combined with histological examination, is the gold standard for GC diagnosis, its high cost, invasiveness, and specialized requirements hinder widespread use for screening. With the emergence of innovative technologies such as advanced imaging, liquid biopsy, and breath tests, the landscape of GC diagnosis is poised for radical transformation, becoming more accessible, less invasive, and more efficient. As the non-invasive diagnostic techniques continue to advance and undergo rigorous clinical validation, they hold the promise of significantly impacting patient outcomes, ultimately leading to better treatment results and improved quality of life for patients with GC.

Non-coding RNA in the Regulation of Gastric Cancer Tumorigenesis: Focus on microRNAs and Exosomal microRNAs

Gastric cancer has become the leading type of cancer on an international scale, with metastatic cancer being the leading cause of mortality associated with this illness. Consequently, methods for early detection have been established, mainly through the use of non-invasive biomarkers present in different bodily fluids. Exosomes are distinct extracellular vehicles that transport cellular signals over long distances via diverse contents. They may be readily seen in bodily fluids due to their secretion by gastric cancer cells or cells in the gastric cancer-tumor microenvironment. Given this context, multiple biological and functional features of human tumors, especially gastric cancer, are intricately connected to exosomal non-coding RNAs (ncRNAs). Exosomal microRNAs play a crucial role in several stages of gastric cancer progression, facilitating the transfer of genetic information between cancer cells and other cells. This process regulates tumor angiogenesis, growth, metastasis, immunological responses, and medication resistance. They engage with several regulatory complexes that have different enzymatic activities. These complexes then alter the chromatin landscapes, including changes to nucleosomes, DNA methylation, and alterations to histones. This research delves into the essential regulatory mechanisms of exosomes in gastric cancer. Furthermore, the existing understanding of the functions of exosomal miRNAs in this context was evaluated, aiming to confirm their potential significance in identifying biomarkers, elucidating their roles in immune evasion and drug resistance, and ultimately evaluating therapeutic strategies.

Exosome-Derived Non-Coding RNAs in the Tumor Microenvironment of Colorectal Cancer: Possible Functions, Mechanisms and Clinical Applications

Colorectal cancer (CRC) is the second leading cause of cancer death and the third most prevalent malignancy. Colorectal tumors exchange information with the surrounding environment and influence each other, which collectively constitutes the tumor microenvironment (TME) of CRC. Many studies have shown that exosome-derived non-coding RNAs (ncRNAs) play important roles in various pathophysiological processes by regulating the TME of CRC. This review summarizes recent findings on the fundamental roles of exosomal ncRNAs in angiogenesis, vascular permeability, tumor immunity, tumor metabolism and drug resistance. Certainly, the in-depth understanding of exosomal ncRNAs will provide comprehensive insights into the clinical application of these molecules against CRC.

The RAL Enigma: Distinct Roles of RALA and RALB in Cancer

RALA and RALB are highly homologous small G proteins belonging to the RAS superfamily. Like other small GTPases, the RALs are molecular switches that can be toggled between inactive GDP-bound and active GTP-bound states to regulate diverse and critical cellular functions such as vesicle trafficking, filopodia formation, mitochondrial fission, and cytokinesis. The RAL paralogs are activated and inactivated by a shared set of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) and utilize similar sets of downstream effectors. In addition to their important roles in normal cell biology, the RALs are known to be critical mediators of cancer cell survival, invasion, migration, and metastasis. However, despite their substantial similarities, the RALs often display striking functional disparities in cancer. RALA and RALB can have redundant, unique, or even antagonistic functions depending on cancer type. The molecular basis for these discrepancies remains an important unanswered question in the field of cancer biology. In this review we examine the functions of the RAL paralogs in normal cellular physiology and cancer biology with special consideration provided to situations where the roles of RALA and RALB are non-redundant.