Exosomal ncRNAs facilitate interactive 'dialogue' between tumor cells and tumor-associated macrophages

The stimulation of exosome generation by visfatin polarizes M2 macrophages and enhances the motility of chondrosarcoma

Chondrosarcoma is a malignant bone tumor that arises from abnormalities in cartilaginous tissue and is associated with lung metastases. Extracellular vesicles called exosomes are primarily used as mediators of intercellular signal transmission to control tumor metastasis. Visfatin is an adipokine reported to enhance tumor metastasis, but its relationship with exosome generation in chondrosarcoma motility remains undetermined. Our results found that overexpressing visfatin augments the production of exosomes from chondrosarcoma cells. Visfatin-treated chondrosarcoma exosomes educate macrophage polarization towards the M2 but not M1 phenotype. Interestingly, M2 macrophages polarized by exosomes return to chondrosarcoma cells to facilitate cell motility. According to these findings, chondrosarcoma cells emit more exosomes when treated with visfatin. The stimulation of exosome generation by visfatin polarizes M2 macrophages and enhances the motility of chondrosarcoma.

Biological functions and clinical significance of tRNA-derived small fragment (tsRNA) in tumors: Current state and future perspectives

A new class of noncoding RNAs, tsRNAs are not only abundant in humans but also have high tissue specificity. Recently, an increasing number of studies have explored the correlations between tsRNAs and tumors, showing that tsRNAs can affect biological behaviors of tumor cells, such as proliferation, apoptosis and metastasis, by modulating protein translation, RNA transcription or posttranscriptional regulation. In addition, tsRNAs are widely distributed and stably expressed, which endows them with broad application prospects in diagnosing and predicting the prognosis of tumors, and they are expected to become new biomarkers. However, notably, the current research on tsRNAs still faces problems that need to be solved. In this review, we describe the characteristics of tsRNAs as well as their unique features and functions in tumors. Moreover, we also discuss the potential opportunities and challenges in clinical applications and research of tsRNAs.

NF-κB: Governing Macrophages in Cancer

Tumor-associated macrophages (TAMs) are the major component of the tumor microenvironment (TME), where they sustain tumor progression and or-tumor immunity. Due to their plasticity, macrophages can exhibit anti- or pro-tumor functions through the expression of different gene sets leading to distinct macrophage phenotypes: M1-like or pro-inflammatory and M2-like or anti-inflammatory. NF-κB transcription factors are central regulators of TAMs in cancers, where they often drive macrophage polarization toward an M2-like phenotype. Therefore, the NF-κB pathway is an attractive therapeutic target for cancer immunotherapy in a wide range of human tumors. Hence, targeting NF-κB pathway in the myeloid compartment is a potential clinical strategy to overcome microenvironment-induced immunosuppression and increase anti-tumor immunity. In this review, we discuss the role of NF-κB as a key driver of macrophage functions in tumors as well as the principal strategies to overcome tumor immunosuppression by targeting the NF-κB pathway.

Effects of extracellular vesicle-derived noncoding RNAs on pre-metastatic niche and tumor progression

A pre-metastatic niche (PMN) is a protective microenvironment that facilitates the colonization of disseminating tumor cells in future metastatic organs. Extracellular vesicles (EVs) play a role in intercellular communication by delivering cargoes, such as noncoding RNAs (ncRNAs). The pivotal role of extracellular vesicle-derived noncoding RNAs (EV-ncRNAs) in the PMN has attracted increasing attention. In this review, we summarized the effects of EV-ncRNAs on the PMN in terms of immunosuppression, vascular permeability and angiogenesis, inflammation, metabolic reprogramming, and fibroblast alterations. In particular, we provided a comprehensive overview of the effects of EV-ncRNAs on the PMN in different cancers. Finally, we discussed the promising clinical applications of EV-ncRNAs, including their potential as diagnostic and prognostic markers and therapeutic targets.

Hypoxia-regulated exosomes mediate M2 macrophage polarization and promote metastasis in chondrosarcoma

Chondrosarcoma is a primary malignant bone tumor. Traditional therapy is not very effective, and it is prone to metastasis in the late stage. The tumor microenvironment (TME) plays a key role in the progression and metastasis of chondrosarcoma, and hypoxia is one of the key factors in the formation of TME. However, the detailed mechanism of how hypoxia affects tumor progression and metastasis in chondrosarcoma is still not fully understood. In this study, we focused on the mechanism of interaction between hypoxic chondrosarcoma cells (SW1353) and macrophages. Our results suggest that hypoxia enhances the release of exosomes from chondrosarcoma cells. These hypoxia-induced exosomes promoted macrophage polarization towards the M2 phenotype, characterized by the expression of CD163 and CD206, but not the M1 phenotype, characterized by CD86 expression. Further analysis revealed that M2 macrophages polarized by exosomes expressed arginase-1 and feedback to chondrosarcoma cells to promote migration. These results suggest that chondrosarcoma cells secrete more exosomes in a hypoxic microenvironment, and these hypoxia-derived exosomes induce the polarization of macrophages into an M2 phenotype, ultimately promoting the metastatic behavior of chondrosarcoma cells.

Communicator Extraordinaire: Extracellular Vesicles in the Tumor Microenvironment Are Essential Local and Long-Distance Mediators of Cancer Metastasis

Human tumors are increasingly being described as a complex "ecosystem", that includes many different cell types, secreted growth factors, extracellular matrix (ECM) components, and microvessels, that altogether create the tumor microenvironment (TME). Within the TME, epithelial cancer cells control the function of surrounding stromal cells and the non-cellular ECM components in an intricate orchestra of signaling networks specifically designed for cancer cells to exploit surrounding cells for their own benefit. Tumor-derived extracellular vesicles (EVs) released into the tumor microenvironment are essential mediators in the reprogramming of surrounding stromal cells, which include cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), tumor-infiltrating lymphocytes (TILs), and tumor endothelial cells (TECs), which are responsible for the promotion of neo-angiogenesis, immune cell evasion, and invasion which are essential for cancer progression. Perhaps most importantly, tumor-derived EVs play critical roles in the metastatic dissemination of tumor cells through their two-fold role in initiating cancer cell invasion and the establishment of the pre-metastatic niche, both of which are vital for tumor cell migration, homing, and colonization at secondary tumor sites. This review discusses extracellular vesicle trafficking within the tumor microenvironment and pre-metastatic niche formation, focusing on the complex role that EVs play in orchestrating cancer-to-stromal cell communication in order to promote the metastatic dissemination of cancer cells.

Potassium Channels, Glucose Metabolism and Glycosylation in Cancer Cells

Potassium channels emerge as one of the crucial groups of proteins that shape the biology of cancer cells. Their involvement in processes like cell growth, migration, or electric signaling, seems obvious. However, the relationship between the function of K+ channels, glucose metabolism, and cancer glycome appears much more intriguing. Among the typical hallmarks of cancer, one can mention the switch to aerobic glycolysis as the most favorable mechanism for glucose metabolism and glycome alterations. This review outlines the interconnections between the expression and activity of potassium channels, carbohydrate metabolism, and altered glycosylation in cancer cells, which have not been broadly discussed in the literature hitherto. Moreover, we propose the potential mediators for the described relations (e.g., enzymes, microRNAs) and the novel promising directions (e.g., glycans-orinented drugs) for further research.

The role of macrophages in the tumor microenvironment and tumor metabolism

The complexity and plasticity of the tumor microenvironment (TME) make it difficult to fully understand the intratumoral regulation of different cell types and their activities. Macrophages play a crucial role in the signaling dynamics of the TME. Among the different subtypes of macrophages, tumor-associated macrophages (TAMs) are often associated with poor prognosis, although some subtypes of TAMs can at the same time improve treatment responsiveness and lead to favorable clinical outcomes. TAMs are key regulators of cancer cell proliferation, metastasis, angiogenesis, extracellular matrix remodeling, tumor metabolism, and importantly immunosuppression in the TME by modulating various chemokines, cytokines, and growth factors. TAMs have been identified as a key contributor to resistance to chemotherapy and cancer immunotherapy. In this review article, we aim to discuss the mechanisms by which TAMs regulate innate and adaptive immune signaling in the TME and summarize recent preclinical research on the development of therapeutics targeting TAMs and tumor metabolism.

Targeting Tumor-Associated Macrophages for Imaging

As an important component of the tumor immune microenvironment (TIME), tumor-associated macrophages (TAMs) occupy a significant niche in tumor margin aggregation and respond to changes in the TIME. Thus, targeting TAMs is important for tumor monitoring, surgical guidance and efficacy evaluation. Continuously developing nanoprobes and imaging agents paves the way toward targeting TAMs for precise imaging and diagnosis. This review summarizes the commonly used nanomaterials for TAM targeting imaging probes, including metal-based nanoprobes (iron, manganese, gold, silver), fluorine-19-based nanoprobes, radiolabeled agents, near-infrared fluorescence dyes and ultrasonic nanobubbles. Additionally, the prospects and challenges of designing nanomaterials for imaging and diagnosis (targeting efficiency, pharmacokinetics, and surgery guidance) are described in this review. Notwithstanding, TAM-targeting nanoplatforms provide great potential for imaging, diagnosis and therapy with a greater possibility of clinical transformation.

Barrier Membranes for Guided Bone Regeneration (GBR): A Focus on Recent Advances in Collagen Membranes

Guided bone regeneration (GBR) has become a clinically standard modality for the treatment of localized jawbone defects. Barrier membranes play an important role in this process by preventing soft tissue invasion outgoing from the mucosa and creating an underlying space to support bone growth. Different membrane types provide different biological mechanisms due to their different origins, preparation methods and structures. Among them, collagen membranes have attracted great interest due to their excellent biological properties and desired bone regeneration results to non-absorbable membranes even without a second surgery for removal. This work provides a comparative summary of common barrier membranes used in GBR, focusing on recent advances in collagen membranes and their biological mechanisms. In conclusion, the review article highlights the biological and regenerative properties of currently available barrier membranes with a particular focus on bioresorbable collagen-based materials. In addition, the advantages and disadvantages of these biomaterials are highlighted, and possible improvements for future material developments are summarized.