Long non-coding RNAs and circular RNAs in tumor angiogenesis: From mechanisms to clinical significance

Searching for the Holy Grail - Highly Potent Bridged Endoperoxides for Targeted Cancer Therapy

The International Agency for Research on Cancer (IARC) recently estimated the global cancer burden in 2050. The statistics are startling, with a 77% hike and 35 million new cancer cases per year. The present discoveries have recommended plant-derived bridged endoperoxides or artemisinin-based semisynthetic analogues as safe, well-tolerated and powerful substitutes that could be effectively utilized as a warhead to fight against global enemies like cancer. In addition, artemisinin-based drug repositioning crucially can reduce overriding drug development expenditures and establish accessibility of approved drugs with low risk to patients. Hence, the present review article provides a comprehensive account of the recent chemical and synthetic advancement of diverse cytotoxic artemisinin derivatives such as C(10)-O, C, N, S linked artemisinin analogues, artemisinin-derived metal complexes, artemisinin-derived hybrids/conjugates with other pharmaceutically active substances, and artemisinin-derived dimers, trimers and tetramers perceived during the last three decades (1997-2024). Moreover, the current preclinical and clinical anticancer application prospects of artemisinin derivatives with other defined drugs and their utilization in combination therapy and also nanoformulation approaches for targeted drug delivery have been discussed.

Havoc in harmony: Unravelling the intricacies of angiogenesis orchestrated by the tumor microenvironment

Cancer cells merely exist in isolation; rather, they exist in an intricate microenvironment composed of blood vessels, signalling molecules, immune cells, stroma, fibroblasts, and the ECM. The TME provides a setting that is favourable for the successful growth and survivance of tumors. Angiogenesis is a multifaceted process that is essential for the growth, invasion, and metastasis of tumors. TME can be visualized as a "concert hall," where various cellular and non-cellular factors perform in a "symphony" to orchestrate tumor angiogenesis and create "Havoc" instead of "Harmony". In this review, we comprehensively summarized the involvement of TME in regulating tumor angiogenesis. Especially, we have focused on immune cells and their secreted factors, inflammatory cytokines and chemokines, and their role in altering the TME. We have also deciphered the crosstalk among various cell types that further aids the process of tumor angiogenesis. Additionally, we have highlighted the limitations of existing anti-angiogenic therapy and discussed various potential strategies that could be used to overcome these challenges and improve the efficacy of anti-angiogenic therapy.

Tumor cells-derived exosomal noncoding RNAs in cancer angiogenesis: Molecular mechanisms and prospective

Exosomes, heterogeneous, membrane-bound nanoparticles that originated from eukaryotic cells, contribute to intracellular communication by transferring various biomolecules both on their surface and as internal cargo. One of the most significant current discussions on cancer progression is noncoding RNAs cargo of exosomes, which can regulate angiogenesis in tumor. A growing body of evidence shows that exosomes from tumor cells contain various microRNAs, long noncoding RNAs, and circular RNAs that can promote tumor progression by inducing angiogenesis. However, some noncoding RNAs may inhibit cancer angiogenesis. Targeting angiogenic noncoding RNA of exosomes may serve as a hopeful implement for cancer therapy. In this review, we discuss the latest knowledge of the roles of exosomal noncoding RNAs in tumor angiogenesis Understanding the biology of exosomal noncoding RNAs can help scientists plan exosomes-based innovations for the treatment of cancer angiogenesis and cancer biomarkers.

Targeting long non-coding RNAs as new modulators in anti-EGFR resistance mechanisms

Epidermal growth factor receptor (EGFR) is a cell surface protein that plays a vital role in regulating cell growth and division. However, certain tumors, such as colorectal cancer (CRC), can exhibit an overexpression of EGFR, resulting in uncontrolled cell growth and tumor progression. To address this issue, therapies targeting and inhibiting EGFR activity have been developed to suppress cancer growth. Nevertheless, resistance to these therapies poses a significant obstacle in cancer treatment. Recent research has focused on comprehending the underlying mechanisms contributing to anti-EGFR resistance and identifying new targets to overcome this striking challenge. Long non-coding RNAs (lncRNAs) are a class of RNA molecules that do not encode proteins but play pivotal roles in gene regulation and cellular processes. Emerging evidence suggests that lncRNAs may participate in modulating resistance to anti-EGFR therapies in CRC. Consequently, combining lncRNA targeting with the existing treatment modalities could potentially yield improved clinical outcomes. Illuminating the involvement of lncRNAs in anti-EGFR resistance mechanisms of cancer cells can provide valuable insights into the development of novel anti-EGFR therapies in several solid tumors.

The novel angiogenesis regulator circFAM169A promotes the metastasis of colorectal cancer through the angiopoietin-2 signaling axis

BACKGROUND

Angiogenesis plays an important role in the metastasis of cancers. However, the mechanisms whereby circular RNAs (circRNAs) regulate angiogenesis and affect cancer metastasis are still unclear.

METHODS

We used gene set variation and Spearman's correlation analyses to identify novel angiogenesis-related circRNAs, including circFAM169A. The Kyoto Encyclopedia of Genes and Genomes and Gene Ontology were used to assess the potential biological function of circFAM169A. A quantitative reverse transcription-PCR (qRT-PCR) analysis of 20 pairs of colorectal cancer (CRC) samples was performed to detect the expression level of circFAM169A. Transwell assays, tube formation assays, and nude mouse metastatic tumor models were used to study the function of circFAM169A in CRC. qRT-PCR, dual-luciferase reporter gene assay, RNA antisense purification assay, and Western blot were performed to analyze the competing endogenous RNA mechanism of circFAM169A in promoting CRC angiogenesis.

RESULTS

circFAM169A was highly correlated with the hallmark of angiogenesis in CRC patients. It was up-regulated in liver metastasized CRC patients. circFAM169A overexpression promoted the angiogenesis, migration, and invasion of CRC cells while its down-regulation had the opposite effects. In vivo mouse models further highlighted the pro-metastatic role of circFAM169A in CRC. More importantly, we discovered that circFAM169A enhances the expression of angiopoietin-2 by binding to miR-518a-5p.

LINC01137/miR-186-5p/WWOX: a novel axis identified from WWOX-related RNA interactome in bladder cancer

Introduction: The discovery of non-coding RNA (ncRNA) dates back to the pre-genomics era, but the progress in this field is still dynamic and leverages current post-genomics solutions. WWOX is a global gene expression modulator that is scarcely investigated for its role in regulating cancer-related ncRNAs. In bladder cancer (BLCA), the link between WWOX and ncRNA remains unexplored. The description of AP-2α and AP-2γ transcription factors, known as WWOX-interacting proteins, is more commonplace regarding ncRNA but still merits investigation. Therefore, this in vitro and in silico study aimed to construct an ncRNA-containing network with WWOX/AP-2 and to investigate the most relevant observation in the context of BLCA cell lines and patients. Methods: RT-112, HT-1376, and CAL-29 cell lines were subjected to two stable lentiviral transductions. High-throughput sequencing of cellular variants (deposited in the Gene Expression Omnibus database under the GSE193659 record) enabled the investigation of WWOX/AP-2-dependent differences using various bioinformatics tools (e.g., limma-voom, FactoMineR, multiple Support Vector Machine Recursive Feature Elimination (mSVM-RFE), miRDB, Arena-Idb, ncFANs, RNAhybrid, TargetScan, Protein Annotation Through Evolutionary Relationships (PANTHER), Gene Transcription Regulation Database (GTRD), or Evaluate Cutpoints) and repositories such as The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia. The most relevant observations from cap analysis gene expression sequencing (CAGE-seq) were confirmed using real-time PCR, whereas TCGA data were validated using the GSE31684 cohort. Results: The first stage of the whole study justified focusing solely on WWOX rather than on WWOX combined with AP-2α/γ. The most relevant observation of the developed ncRNA-containing network was LINC01137, i.e., long non-coding RNAs (lncRNAs) that unraveled the core network containing UPF1, ZC3H12A, LINC01137, WWOX, and miR-186-5p, the last three being a novel lncRNA/miRNA/mRNA axis. Patients' data confirmed the LINC01137/miR-186-5p/WWOX relationship and provided a set of dependent genes (i.e., KRT18, HES1, VCP, FTH1, IFITM3, RAB34, and CLU). Together with the core network, the gene set was subjected to survival analysis for both TCGA-BLCA and GSE31684 patients, which indicated that the increased expression of WWOX or LINC01137 is favorable, similar to their combination with each other (WWOX↑ and LINC01137↑) or with MIR186 (WWOX↑/LINC01137↑ but MIR186↓). Conclusion: WWOX is implicated in the positive feedback loop with LINC01137 that sponges WWOX-targeting miR-186-5p. This novel WWOX-containing lncRNA/miRNA/mRNA axis should be further investigated to depict its relationships in a broader context, which could contribute to BLCA research and treatment.

The role of tumor-derived extracellular vesicles containing noncoding RNAs in mediating immune cell function and its implications from bench to bedside

Extracellular vesicles (EVs) are membrane-encapsulated vesicles released by almost all cell types, which participate in intercellular communication by delivering different types of molecular cargoes, such as non-coding RNAs (ncRNAs). Accumulating evidence suggests that tumor-derived EVs act as a bridge for intercellular crosstalk between tumor cells and surrounding cells, including immune cells. Tumor-derived EVs containing ncRNAs (TEV-ncRNAs) mediate intercellular crosstalk to manipulate immune responses and affect the malignant phenotypes of cancer cells. In this review, we summarize the double-edged roles and the underlying mechanisms of TEV-ncRNAs in regulating innate and adaptive immune cells. We also highlight the advantages of using TEV-ncRNAs in liquid biopsies for cancer diagnosis and prognosis. Moreover, we outline the use of engineered EVs to deliver ncRNAs and other therapeutic agents for cancer therapy.

The Roles of Exosomes in Metastasis of Sarcoma: From Biomarkers to Therapeutic Targets

Sarcoma is a heterogeneous group of mesenchymal neoplasms with a high rate of lung metastasis. The cellular mechanisms responsible for sarcoma metastasis remain poorly understood. Furthermore, there are limited efficacious therapeutic strategies for treating metastatic sarcoma. Improved diagnostic and therapeutic modalities are of increasing importance for the treatment of sarcoma due to their high mortality in the advanced stages of the disease. Recent evidence demonstrates that the exosome, a type of extracellular vesicle released by virtually all cells in the body, is an important facilitator of intercellular communication between the cells and the surrounding environment. The exosome is gaining significant attention among the medical research community, but there is little knowledge about how the exosome affects sarcoma metastasis. In this review, we summarize the multifaceted roles of sarcoma-derived exosomes in promoting the process of metastasis via the formation of pre-metastatic niche (PMN), the regulation of immunity, angiogenesis, vascular permeability, and the migration of sarcoma cells. We also highlight the potential of exosomes as innovative diagnostic and prognostic biomarkers as well as therapeutic targets in sarcoma metastasis.

Extracellular vesicles: A new diagnostic biomarker and targeted drug in osteosarcoma

Osteosarcoma (OS) is a primary bone cancer that is highly prevalent among adolescents and adults below the age of 20 years. The prognostic outcome of metastatic OS or relapse is extremely poor; thus, developing new diagnostic and therapeutic strategies for treating OS is necessary. Extracellular vesicles (EVs) ranging from 30–150 nm in diameter are commonly produced in different cells and are found in various types of body fluids. EVs are rich in biologically active components like proteins, lipids, and nucleic acids. They also strongly affect pathophysiological processes by modulating the intercellular signaling pathways and the exchange of biomolecules. Many studies have found that EVs influence the occurrence, development, and metastasis of osteosarcoma. The regulation of inflammatory communication pathways by EVs affects OS and other bone-related pathological conditions, such as osteoarthritis and rheumatoid arthritis. In this study, we reviewed the latest findings related to diagnosis, prognosis prediction, and the development of treatment strategies for OS from the perspective of EVs.

Long Noncoding RNAs and Circular RNAs in the Metabolic Reprogramming of Lung Cancer: Functions, Mechanisms, and Clinical Potential

As key regulators of gene function, long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are generally accepted to be involved in lung cancer pathogenesis and progression. Recent research has clarified the phenomenon of metabolic reprogramming in lung cancer because of its significant role in tumor proliferation, migration, invasion, metastasis, and other malignant biological behaviors. Emerging evidence has also shown a relationship between the aberrant expression of lncRNAs and circRNAs and metabolic reprogramming in lung cancer tumorigenesis. This review provides insight regarding the roles of different lncRNAs and circRNAs in lung cancer metabolic reprogramming, by how they target transporter proteins and key enzymes in glucose, lipid, and glutamine metabolic signaling pathways. The clinical potential of lncRNAs and circRNAs as early diagnostic biomarkers and components of therapeutic strategies in lung cancer is further discussed, including current challenges in their utilization from the bench to the bedside and how to adopt a proper delivery system for their therapeutic use.

The role of long non-coding RNA FGD5-AS1 in cancer

Long noncoding RNAs (lncRNAs) refers to a class of RNAs that have at least 200 nucleotides and do not encode proteins, and the relationship between lncRNA and cancer has recently attracted considerable research attention. The lncRNA FGD5-AS1 is a newly discovered lncRNA with a length of 3772 nucleotides. Studies have found that FGD5-AS1 is abnormally highly expressed in many cancer tissues and was closely related to the lymph node metastasis, tumor invasion, survival time, and recurrence rate of various cancers. Mechanistic analyses show that FGD5-AS1 can stabilize mRNA expression by sponging miRNA, which not only induces cancer cell proliferation, metastasis, invasion, and chemoresistance in vitro, but also promotes tumor growth and metastasis in vivo. In addition, FGD5-AS1 can serve as a diagnostic or prognostic marker for a variety of cancers. This review demonstrates the clinical significance of FGD5-AS1 in human cancer and its role in tumorigenesis and tumor progression.

Hypoxia-Induced circRNAs in Human Diseases: From Mechanisms to Potential Applications

Circular RNAs (circRNAs) are a special class of endogenous RNAs characterized by closed loop structures lacking 5′ to 3′ polarity and polyadenylated tails. They are widely present in various organisms and are more stable and conserved than linear RNAs. Accumulating evidence indicates that circRNAs play important roles in physiology-related processes. Under pathological conditions, hypoxia usually worsens disease progression by manipulating the microenvironment for inflammation and invasion through various dysregulated biological molecules. Among them, circRNAs, which are involved in many human diseases, including cancer, are associated with the overexpression of hypoxia-inducible factors. However, the precise mechanisms of hypoxic regulation by circRNAs remain largely unknown. This review summarizes emerging evidence regarding the interplay between circRNAs and hypoxia in the pathophysiological changes of diverse human diseases, including cancer. Next, the impact of hypoxia-induced circRNAs on cancer progression, therapeutic resistance, angiogenesis, and energy metabolism will be discussed. Last, but not least, the potential application of circRNAs in the early detection, prognosis, and treatment of various diseases will be highlighted.

Noncoding RNAs of Extracellular Vesicles in Tumor Angiogenesis: From Biological Functions to Clinical Significance

Extracellular vesicles (EVs) act as multifunctional regulators of intercellular communication and are involved in diverse tumor phenotypes, including tumor angiogenesis, which is a highly regulated multi-step process for the formation of new blood vessels that contribute to tumor proliferation. EVs induce malignant transformation of distinct cells by transferring DNAs, proteins, lipids, and RNAs, including noncoding RNAs (ncRNAs). However, the functional relevance of EV-derived ncRNAs in tumor angiogenesis remains to be elucidated. In this review, we summarized current research progress on the biological functions and underlying mechanisms of EV-derived ncRNAs in tumor angiogenesis in various cancers. In addition, we comprehensively discussed the potential applications of EV-derived ncRNAs as cancer biomarkers and novel therapeutic targets to tailor anti-angiogenic therapy.

Repurposing Artemisinin and its Derivatives as Anticancer Drugs: A Chance or Challenge?

Cancer has become a global health problem, accounting for one out of six deaths. Despite the recent advances in cancer therapy, there is still an ever-growing need for readily accessible new therapies. The process of drug discovery and development is arduous and takes many years, and while it is ongoing, the time for the current lead compounds to reach clinical trial phase is very long. Drug repurposing has recently gained significant attention as it expedites the process of discovering new entities for anticancer therapy. One such potential candidate is the antimalarial drug, artemisinin that has shown anticancer activities in vitro and in vivo. In this review, major molecular and cellular mechanisms underlying the anticancer effect of artemisinin and its derivatives are summarised. Furthermore, major mechanisms of action and some key signaling pathways of this group of compounds have been reviewed to explore potential targets that contribute to the proliferation and metastasis of tumor cells. Despite its established profile in malaria treatment, pharmacokinetic properties, anticancer potency, and current formulations that hinder the clinical translation of artemisinin as an anticancer agent, have been discussed. Finally, potential solutions or new strategies are identified to overcome the bottlenecks in repurposing artemisinin-type compounds as anticancer drugs.

LncRNAs and the Angiogenic Switch in Cancer: Clinical Significance and Therapeutic Opportunities

Angiogenesis is one of the hallmarks of cancer, and the establishment of new blood vessels is vital to allow for a tumour to grow beyond 1-2 mm in size. The angiogenic switch is the term given to the point where the number or activity of the pro-angiogenic factors exceeds that of the anti-angiogenic factors, resulting in the angiogenic process proceeding, giving rise to new blood vessels accompanied by increased tumour growth, metastasis, and potential drug resistance. Long noncoding ribonucleic acids (lncRNAs) have been found to play a role in the angiogenic switch by regulating gene expression, transcription, translation, and post translation modification. In this regard they play both anti-angiogenic and pro-angiogenic roles. The expression levels of the pro-angiogenic lncRNAs have been found to correlate with patient survival. These lncRNAs are also potential drug targets for the development of therapies that will inhibit or modify tumour angiogenesis. Here we review the roles of lncRNAs in regulating the angiogenic switch. We cover specific examples of both pro and anti-angiogenic lncRNAs and discuss their potential use as both prognostic biomarkers and targets for the development of future therapies.

The potential role of exosomal circRNAs in the tumor microenvironment: insights into cancer diagnosis and therapy

Exosomes are multifunctional regulators of intercellular communication by carrying various messages under both physiological and pathological status of cancer patients. Accumulating studies have identified the presence of circular RNAs (circRNAs) in exosomes with crucial regulatory roles in diverse pathophysiological processes. Exosomal circRNAs derived from donor cells can modulate crosstalk with recipient cells locally or remotely to enhance cancer development and propagation, and play crucial roles in the tumor microenvironment (TME), leading to significant enhancement of tumor immunity, metabolism, angiogenesis, drug resistance, epithelial mesenchymal transition (EMT), invasion and metastasis. In this review, we describe the advances of exosomal circRNAs and their roles in modulating cancer hallmarks, especially those in the TME. Moreover, clinical application potential of exosomal circRNAs in cancer diagnosis and therapy are highlighted, bridging the gap between basic knowledge and clinical practice.