MicroRNAs in the Tumor Microenvironment

Ion Channels as a Therapeutic Target: Drug Design and Pharmacological Investigation

This Special Issue intends to illustrate the novelties in the field of ion channels [...].

JAK1 Is a Novel Target of Tumor- and Invasion-Suppressive microRNA 494-5p in Colorectal Cancer

MiR-494-5p expression has been suggested to be associated with colorectal cancer (CRC) and its metastases in our previous studies. However, functional investigations on the molecule-mediating actions of this miR in CRC are lacking. In silico analysis in the present study revealed a putative binding sequence within the 3'UTR of JAK1. Overexpression of miR-494-5p in cultured CRC significantly reduced the luciferase activity of a reporter plasmid containing the wild-type JAK1-3'UTR, which was abolished by seed sequence mutation. Furthermore, the overexpression of miR-494-5p in CRC cell lines led to a significant reduction in JAK1 expression, proliferation, in vitro migration, and invasion. These effects were abolished by co-transfection with a specific double-stranded RNA that inhibits endogenous miR-494-5p. Moreover, IL-4-induced migration, invasion, and phosphorylation of JAK1, STAT6, and AKT proteins were reduced after an overexpression of this miR, suggesting that this miR affects one of the most essential pathways in CRC. A Kaplan-Meier plotter analysis revealed that patients with high JAK1 expression show reduced survival. Together, these data suggest that miR-494-5p physically inhibits the expression of JAK1 at the translational level as well as in migration and invasion, supporting the hypothesis of miR-494-5p as an early tumor suppressor and inhibitor of early steps of metastasis in CRC.

The role of noncoding RNAs in the tumor microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the leading fatal malignancy worldwide. The tumor microenvironment (TME) can affect the survival, proliferation, migration, and even dormancy of cancer cells. Hypoxia is an important component of the TME, and hypoxia-inducible factor-1α (HIF-1α) is the most important transcriptional regulator. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), comprise a large part of the human transcriptome and play an important role in regulating the tumorigenesis of HCC. This review discusses the role of ncRNAs in hepatocarcinogenesis, epithelial-mesenchymal transition (EMT), and angiogenesis in a hypoxic microenvironment, as well as the interactions between ncRNAs and key components of the TME. It further discusses their use as biomarkers and the potential clinical value of drugs, as well as the challenges faced in the future.

Targeting microRNAs as a promising anti-cancer therapeutic strategy against traffic-related air pollution-mediated lung cancer

Air pollutants are increasingly emitted into the atmosphere because of the high dependency of humans on fossil-derived fuels. Wind speed and direction assisted high dispersibility and uncontrolled nature of air pollution across geo-/demographical borders, making it one of the major global concerns. Besides climate change, air pollution has been found to be associated with various diseases, such as cancer. Lung cancer, which is the world's most common type of cancer, has been found to be associated with traffic-related air pollution. Research and political efforts have been taken to explore green/renewable energy sources. However, these efforts at the current intensity cannot cope with the increasing need for fossil fuels. More specifically, political tensions such as the Russian-Ukraine war, economic tension (e.g., China-USA economic tensions), and other issues (e.g., pandemic, higher inflation rate, and poverty) significantly hindered phasing out fossil fuels. In this context, an increasing global population will be exposed to traffic-related air pollution, which justifies the current uptrend in the number of lung cancer patients. To combat this health burden, novel treatments with higher efficiency and specificity must be designed. One of the potential "life changer" options is microRNA (miRNA)-based therapy to target the expression of oncogenic genes. That said, this review discusses the association of traffic-related air pollution with lung cancer, the changes in indigenous miRNAs in the body during lung cancer, and the current status of miRNA therapeutics for lung cancer treatment. We believe that the article will significantly appeal to a broad readership of oncologists, environmentalists, and those who work in the field of (bio)energy. It may also gain the policymakers' attention to establish better health policies and regulations about air pollution, for example, by promoting (bio)fuel exploration, production, and consumption.

Unraveling Therapeutic Opportunities and the Diagnostic Potential of microRNAs for Human Lung Cancer

Lung cancer is a major public health problem and a leading cause of cancer-related deaths worldwide. Despite advances in treatment options, the five-year survival rate for lung cancer patients remains low, emphasizing the urgent need for innovative diagnostic and therapeutic strategies. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets for lung cancer due to their crucial roles in regulating cell proliferation, differentiation, and apoptosis. For example, miR-34a and miR-150, once delivered to lung cancer via liposomes or nanoparticles, can inhibit tumor growth by downregulating critical cancer promoting genes. Conversely, miR-21 and miR-155, frequently overexpressed in lung cancer, are associated with increased cell proliferation, invasion, and chemotherapy resistance. In this review, we summarize the current knowledge of the roles of miRNAs in lung carcinogenesis, especially those induced by exposure to environmental pollutants, namely, arsenic and benzopyrene, which account for up to 1/10 of lung cancer cases. We then discuss the recent advances in miRNA-based cancer therapeutics and diagnostics. Such information will provide new insights into lung cancer pathogenesis and innovative diagnostic and therapeutic modalities based on miRNAs.

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.

Role of miRNA in Melanoma Development and Progression

Melanoma is one of the most aggressive and progressive skin cancers. It develops from normal pigment-producing cells known as melanocytes, so it is important to know the mechanism behind such transformations. The study of metastasis mechanisms is crucial for a better understanding the biology of neoplastic cells. Metastasis of melanoma, or any type of cancer, is a multi-stage process in which the neoplastic cells leave the primary tumour, travel through the blood and/or lymphatic vessels, settle in distant organs and create secondary tumours. MicroRNA (miRNA) can participate in several steps of the metastatic process. This review presents the role of miRNA molecules in the development and progression as well as the immune response to melanoma.

circFCHO2 promotes gastric cancer progression by activating the JAK1/STAT3 pathway via sponging miR-194-5p

circFCHO2 has been revealed to be overexpressed in gastric cancer (GC) patients. This article identified the function of circFCHO2 on GC progression. The expression of circFCHO2, miR-194-5p and JAK1 in 30 GC patients and cells was monitored by quantitative reverse transcription-polymerase chain reaction. circFCHO2 localization in GC cells was monitored by RNA fluorescence in situ hybridization. Cell counting kit-8 assay, 5-ethynyl-2-deoxyuridine staining, transwell experiment, tube formation and sphere formation experiments were applied to detect GC cell proliferation, invasion, angiogenesis and cancer stem cell characteristics. Dual-luciferase reporter gene assay, RNA pull down assay and RNA immunoprecipitation experiment were utilized to research the binding between two genes. In vivo tumorigenesis and lung metastasis were studied using nude mice. Immunohistochemistry and hematoxylin-eosin staining were conducted. Protein expression was assessed by Western blot. Serum exosomes of GC patients and healthy participants were isolated. circFCHO2 up-modulation in GC patients was related to poor outcome. circFCHO2 was located in the cytoplasm of GC cells. circFCHO2 silencing weakened the proliferation, invasion, angiogenesis and stem cell characteristics of GC cells. miR-194-5p knockdown counteracted this effect. circFCHO2 activated the JAK1/STAT3 pathway by sponging miR-194-5p. miR-194-5p overexpression attenuated the malignant phenotypes of GC cells. JAK1 overexpression abrogated this effect. circFCHO2 silencing weakened GC cells growth and lung metastasis in vivo. circFCHO2 was up-modulated in serum exosomes of GC patients. circFCHO2 was an oncogene in GC by activating the JAK1/STAT3 pathway via sponging miR-194-5p. circFCHO2 might be a novel target and diagnostic marker for GC.

Exosomal non-coding RNAs: Emerging roles in bilateral communication between cancer cells and macrophages

The tumor microenvironment (TME) is a dynamic network of cellular organization that comprises diverse cell types and significantly contributes to cancer development. As pivotal immune stromal cells in the TME, macrophages are extensively heterogeneous and exert both antitumor and protumor functions. Exosomes are nanosized extracellular membranous vesicles with diameters between 30 and 150 nm. By transferring multiple bioactive substances such as proteins, lipids, and nucleic acids, exosomes play an important role in the communication between cells. Recently, growing evidence has demonstrated that non-coding RNAs (ncRNAs) are enriched in exosomes and that exosomal ncRNAs are involved in the crosstalk between cancer cells and macrophages. Furthermore, circulating exosomal ncRNAs can be detected in biofluids, serving as promising noninvasive biomarkers for the early diagnosis and prognostic prediction of cancer. Exosome-based therapies are emerging as potent strategies that can be utilized to alleviate tumor progression. Herein, the present knowledge of exosomal ncRNAs and their vital roles in regulating the interplay between cancer cells and macrophages, as well as their clinical applications are summarized.

Circulating microRNAs in Early Breast Cancer Patients and Its Association With Lymph Node Metastases

MicroRNAs have emerged as important regulators of the metastatic process. In addition, circulating miRNAs appear to be surprisingly stable in peripheral blood making them ideal noninvasive biomarkers for disease diagnosis. Here, we performed a proof-of-principle study to investigate the expression profile of circulating miRNAs and their association with the metastatic lymph node status in early breast cancer patients. Sentinel lymph node status was detected by one-step nucleic acid (OSNA) analysis. We performed RNA-sequencing in 16 plasma samples and validated the results by qPCR. Gene Ontology term enrichment and KEGG pathway analyses were carried out using DAVID tools. We found16 differentially expressed miRNAs (q < 0.01) in patients with positive SLNs. Fourteen miRNAs were down-regulated (miR-339-5p, miR-133a-3p, miR-326, miR-331-3p, miR-369-3p, miR-328-3p, miR-26a-3p, miR-139-3p, miR-493-3p, miR-664a-5p, miR-146a-5p, miR-323b-3p, miR-1307-3p and miR-423-3p) and 2 were up-regulated (miR-101-3pand miR-144-3p). Hierarchical clustering using differentially expressed miRNAs clearly distinguished patients according to their lymph node status. Gene ontology analysis showed a significant enrichment of biological processes associated with the regulation of the epithelial mesenchymal transition, cell proliferation and transcriptional regulation. Our results suggest the potential role of several circulating miRNAs as surrogate markers of lymph node metastases in early breast cancer patients. Further validation in a larger cohort of patients will be necessary to confirm our results.

MiR-138-1-3p alters the stemness and radiosensitivity of tumor cells by targeting CRIPTO and the JAK2/STAT3 pathway in nasopharyngeal carcinoma

Background

Tumor resistance to radiotherapy is one of the main obstacles to the clinical treatment of nasopharyngeal carcinoma (NPC). Improving the radiosensitivity of tumor cells has an important clinical significance in treatment of clinical NPC. This study aimed to identify that miR-138-1-3p as a novel therapeutic target in radioresistant NPC cells and found its targets, CRIPTO and the JAK2/STAT3 pathway.

Methods

Radioresistant C666-IR and HK-1R cells were derived from the NPC cell lines C666-1 and HK-1. The different microRNAs (miRNAs) and their targeting genes were analyzed between C666-1 and C666-IR cells using microarray bioinformatics. Western blot, qRT-PCR, gene transfection, Luciferase reporter assay, and confocal laser scanning microscopy were applied for the analysis of the different genes.

Results

MiR-138-1-3p was found to target CRIPTO, which involved in the epithelial-mesenchymal transition (EMT) and JAK2/STAT3 signaling pathways. The luciferase reporter assay confirmed that miR-138-1-3p targeted CRIPTO and downregulated the expression of CRIPTO. Furthermore, miR-138-1-3p affected the stability of the CRIPTO-GRP78 complex on the cell membrane and also reversed the radioresistant characteristics of NPC stem cells, which affected EMT and the JAK2/STAT3 signaling pathway.

Conclusions

The miR-138-1-3p is a small molecule that can modulate radiosensitivity in the radioresistant C666-IR and HK-1R NPC cell lines by inhibiting EMT and targeting CRIPTO to reduce the activation of the JAK2/STAT3 pathway.