MicroRNA-23a inhibits melanoma cell proliferation, migration, and invasion in mice through a negative feedback regulation of sdcbp and the MAPK/ERK signaling pathway

Unveiling the Regulatory Role of LncRNA MYU in Hypoxia-Induced Angiogenesis via the miR-23a-3p Axis in Endothelial Cells

Background: Angiogenesis is essential for various physiological and pathological processes, such as embryonic development and cancer cell proliferation, migration, and invasion. Long noncoding RNAs (lncRNAs) play pivotal roles in normal homeostasis and disease processes by regulating gene expression through various mechanisms, including competing endogenous RNAs (ceRNAs) of target microRNAs (miRNAs). The lncRNA MYU is known to promote prostate cancer proliferation via the miR-184/c-Myc regulatory axis and to be upregulated in vascular endothelial cells under hypoxic conditions, which often occurs in solid tumors. In the present study, we investigated whether MYU might affect cancer growth by regulating angiogenesis in vascular endothelial cells under hypoxia. Methods: The expression of MYU-regulated miR-23a-3p and interleukin-8 (IL-8) in HUVEC cell lines was examined using qRT-PCR. The CCK-8 assay, EdU assay, wound-healing assay, and tube-formation assay were used to assess the effects of MYU on cell proliferation, migration, and tube formation of HUVEC cells in vitro. The dual-luciferase reporter assay was performed to examine the effects of miR-23a-3p on MYU and IL-8 expression. Results: We found that the overexpression of MYU and knockdown of miR-23a-3p in human umbilical vein endothelial cells (HUVECs) under hypoxia promoted cell proliferation, migration, and tube formation. Mechanistically, MYU was shown to bind competitively to miR-23a-3p, thereby preventing miR-23a-3p binding to the 3' untranslated region of IL-8 mRNA. In turn, increased production of pro-angiogenic IL-8 promoted HUVEC proliferation, migration, and tube formation under hypoxia. Conclusion: This study identified a new role for lncRNA MYU as a ceRNA for miR-23a-3p and uncovered a novel MYU-miR-23a-3p-IL-8 regulatory axis for angiogenesis. MYU and/or miR-23a-3p may thus represent new targets for the treatment of hypoxia-related diseases by promoting angiogenesis.

The Multifunctional Protein Syntenin-1: Regulator of Exosome Biogenesis, Cellular Function, and Tumor Progression

Syntenin acts as an adaptor and scaffold protein through its two PSD-95, Dlg, and ZO-1 (PDZ) domains, participating in multiple signaling pathways and modulating cellular physiology. It has been identified as an oncogene, promoting cancer development, metastasis, and angiogenesis in various carcinomas. Syntenin-1 is also associated with the production and release of exosomes, small extracellular vesicles that play a significant role in intercellular communication by containing bioactive molecules such as proteins, lipids, and nucleic acids. The trafficking of exosomes involves a complex interplay of various regulatory proteins, including syntenin-1, which interacts with its binding partners, syndecan and activated leukocyte cell adhesion molecule (ALIX). Exosomal transfer of microRNAs, a key cargo, can regulate the expression of various cancer-related genes, including syntenin-1. Targeting the mechanism involving the regulation of exosomes by syntenin-1 and microRNAs may provide a novel treatment strategy for cancer. This review highlights the current understanding of syntenin-1's role in regulating exosome trafficking and its associated cellular signaling pathways.

Insights into the Molecular Mechanisms Mediating Extravasation in Brain Metastasis of Breast Cancer, Melanoma, and Lung Cancer

Brain metastasis is an incurable end-stage of systemic cancer associated with poor prognosis, and its incidence is increasing. Brain metastasis occurs through a multi-step cascade where cancer cells spread from the primary tumor site to the brain. The extravasation of tumor cells through the blood-brain barrier (BBB) is a critical step in brain metastasis. During extravasation, circulating cancer cells roll along the brain endothelium (BE), adhere to it, then induce alterations in the endothelial barrier to transmigrate through the BBB and enter the brain. Rolling and adhesion are generally mediated by selectins and adhesion molecules induced by inflammatory mediators, while alterations in the endothelial barrier are mediated by proteolytic enzymes, including matrix metalloproteinase, and the transmigration step mediated by factors, including chemokines. However, the molecular mechanisms mediating extravasation are not yet fully understood. A better understanding of these mechanisms is essential as it may serve as the basis for the development of therapeutic strategies for the prevention or treatment of brain metastases. In this review, we summarize the molecular events that occur during the extravasation of cancer cells through the blood-brain barrier in three types of cancer most likely to develop brain metastasis: breast cancer, melanoma, and lung cancer. Common molecular mechanisms driving extravasation in these different tumors are discussed.

Exosomal microRNA-23a-3p contributes to the progression of cholangiocarcinoma by interaction with Dynamin3

Cholangiocarcinoma (abbreviated as CCA) accounts for about 3% of digestive tract tumors, which is a rare disease with relatively low incidence. Herein, we firstly discovered overexpression of microRNA-23a-3p (abbreviated as miR-23a-3p) in CCA tissues, as well as cell lines via bioinformatics prediction. Next, by conducting miR-23a-3p knockdown system in HUCCT1 cells and miR-23a-3p overexpression system in RBE cells, we investigated the biological effects of miR-23a-3p. Based on our findings, inhibition of miR-23a-3p was able to prevent cancer cell proliferation via colony formation, CCK-8, as well as EdU assays. Moreover, invasion as well as migration abilities of cells was examined by transwell assay and wound healing test. Animal study further verified that knockdown miR-23a-3p slowed down tumor growth and lung metastasis. In addition, we identified cholangiocarcinoma cells transferred miR-23a-3p through exosomes by a series of assays. Functional experiments have confirmed that exosomal miR-23a-3p could benefit for cancer cell growth and metastasis, serving as a cancer promoting gene. Furthermore, we found Dynamin3 (abbreviated as DNM3) turned out to be a target of miR-23a-3p, while DNM3 was down-regulated in cholangiocarcinoma. Knockdown DNM3 accelerated cancer cell development. Collectively, our findings firstly pointed out that exosomal miR-23a-3p was conducive to the progression of cholangiocarcinoma by interaction with DNM3, which provided potential evidence for cancer treatment.

An integrative approach identifies dysregulated long non-coding RNAs as microRNA decoys during nevus to melanoma transformation

Mounting evidence supports a role for dysregulated long non-coding RNAs (lncRNA) in the development of many cancers. A recently discovered function of lncRNAs is to act as microRNA (miR) decoys or competing endogenous RNAs, which sequester specific miRs and relieve negative regulation of mRNA expression by miRs. Although a large number of non-coding RNAs are thought to function as competing endogenous RNAs, miR-sequestering lncRNAs involved in nevus to melanoma transformation remain largely unknown. In this study, we applied a bioinformatics approach to a unique dataset of benign melanocytic nevi and primary melanomas of the skin in order to fill this research gap. We modified a previously published miR target prediction algorithm, RNAhybrid, and improved its search efficiency. We reported the presence of many lncRNAs and miRs deregulated when transitioning from a senescence-like state of nevi to melanoma. We provided evidence of a relatively new and understudied mechanism of gene regulation during this process and identified for the first time lncRNAs (n = 122) that may potentially function as miR decoys as well as their target miRs during nevus to melanoma transformation. The knowledge presented here can be employed for developing biomarkers for diagnostic and risk stratification purposes.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

Melanoma is the utmost fatal kind of skin neoplasms. Molecular changes occurring during the pathogenic processes of initiation and progression of melanoma are diverse and include activating mutations in BRAF and NRAS genes, hyper-activation of PI3K/AKT pathway, inactivation of p53 and alterations in CDK4/CDKN2A axis. Moreover, several miRNAs have been identified to be implicated in the biology of melanoma through modulation of expression of genes being involved in these pathways. In the current review, we provide a summary of the bulk of information about the role of miRNAs in the pathobiology of melanoma, their possible application as biomarkers and their emerging role as therapeutic targets for this kind of skin cancer.

LncRNA MIR205HG regulates melanomagenesis via the miR-299-3p/VEGFA axis

In this study, we investigated the role of lncRNA MIR205HG in melanomagenesis. Quantitative real-time PCR (qRT-PCR) analysis showed that MIR205HG levels were significantly upregulated in melanoma cell lines compared to normal human melanocytes. Similarly, MIR205HG levels were significantly higher melanoma tissues than adjacent normal skin tissues (n=30). CCK-8 and flow cytometry assays showed that MIR205HG knockdown significantly decreased the viability of melanoma cells. Dual luciferase reporter and RNA pull-down assays confirmed that MIR205HG directly binds to microRNA (miR)-299-3p. Targetscan analysis and dual luciferase reporter assays showed that miR-299-3p directly binds to the 3'UTR of VEGFA mRNA. Wound healing and transwell invasion assays showed that MIR205HG knockdown decreased in vitro migration and invasiveness of melanoma cells, and these effects were reversed by treatment with miR-299-3p inhibitor. MIR205HG-silenced melanoma cells showed increased miR-299-3p expression and lower levels of both VEGFA mRNA and protein. Tumor volumes were significantly smaller in nude mice xenografted with MIR205HG knockdown melanoma cells than the controls. These results demonstrate that MIR205HG supports melanoma growth via the miR-299-3p/VEGFA axis. This makes MIR205HG a potential therapeutic target for the treatment of melanoma.

Downregulation of SDCBP inhibits cell proliferation and induces apoptosis by regulating PI3K/AKT/mTOR pathway in gastric carcinoma

Syndecan-binding protein (SDCBP) has been reported to critically process a core role in tumorigenesis. This study was conducted to characterize a novel regulatory network of SDCBP in gastric carcinoma (GC) cells. Our findings indicated that overexpression of SDCBP promoted the proliferation of GC cell and increased proliferating cell nuclear antigen (PCNA) expression. Moreover, the overexpression of SDCBP suppressed the apoptosis of GC cell along with a decrease of Bax/Bcl-2 ratio and induction of PI3K/AKT/mTOR activation. However, knockdown of SDCBP exhibited opposed effects on GC cells. Furthermore, silencing SDCBP significantly inhibited GC cell viability and PCNA expression accompanied with the upregulated cell apoptosis and Bax/Bcl-2 ratio, which was regulated by PI3K/AKT/mTOR signaling pathway. And it was further determined that PI3K inhibitor LY294002, AKT inhibitor Torin1, and mTOR inhibitor MK-2206 suppressed the apoptosis. In conclusion, SDCBP promotes the growth ability of GC by inducing the PCNA expression and inhibiting GC cell apoptosis via inactivation of the PI3K/AKT/mTOR pathway.

MicroRNAs as regulators of ERK/MAPK pathway: A comprehensive review

The ERK/MAPK cascade is one the four distinctive MAPK cascades which transmit extracellular signals to intracellular targets. This cascade has an important role in the regulation of several fundamental processes such as proliferation, differentiation and cell response to diverse extrinsic stresses. Moreover, several studies have shown participation of this cascade in the pathogenesis of cancer. Recent investigations have unraveled interaction between microRNAs (miRNAs) and ERK/MAPK cascade. These transcripts reside in both upstream and downstream of this cascade, regulating or being regulated by ERK/MAPK proteins. In the current review, we summarize the role of miRNAs in the regulation of ERK/MAPK and their contribution in the pathogenesis of human disorders with particular focus on cancers.

MicroRNA-23a acts as an oncogene in pancreatic carcinoma by targeting TFPI-2

Pancreatic carcinoma (PC) is a rapidly progressive, fatal malignant tumor with the poorest prognosis among all major carcinoma types. MicroRNAs (miRNAs/miRs) have been indicated to be key post-transcriptional regulatory factors, which are involved in cancer development. The present study was designed to investigate the effect of miR-23a on PC cell proliferation, metastasis and apoptosis. The expression of miR-23a was detected in a normal pancreatic ductal epithelial cell line and three PC cell lines, and miR-23a inhibitor or mimics were transfected into the Panc-1 and MiaPaCa2 PC cells. The association between miR-23a and tissue factor pathway inhibitor (TFPI)-2 was examined using a luciferase reporter assay. MTT and flow cytometry assays were used to assess cell viability and apoptosis, respectively. Furthermore, wound-healing, Transwell and Matrigel assays were used to evaluate cell migration and invasion abilities, and the protein expression level of TFPI-2 was determined using western blot analysis. The results of the present study revealed that miR-23a was upregulated in PC cells. Furthermore, TFPI-2 was identified as a downstream target of miR-23a, and TFPI-2 expression was found to be increased following miR-23a knockdown. In addition, functional assays revealed that downregulation of miR-23a decreased PC cell proliferation, migration and invasiveness and promoted cell apoptosis, while miR-23a overexpression exerted the opposite effects. Furthermore, TFPI-2 knockdown rescued the biological effects on PC cells, which were induced by miR-23a knockdown. The results of the present study indicated that miR-23a negatively modulated TFPI-2 expression in vitro and enhanced the malignant phenotypes of PC cells. Therefore, miR-23a may be a potential marker and/or target for the diagnosis and treatment of PC.

Exosomal miRNAs in tumor microenvironment

Tumor microenvironment (TME) is the internal environment in which tumor cells survive, consisting of tumor cells, fibroblasts, endothelial cells, and immune cells, as well as non-cellular components, such as exosomes and cytokines. Exosomes are tiny extracellular vesicles (40-160nm) containing active substances, such as proteins, lipids and nucleic acids. Exosomes carry biologically active miRNAs to shuttle between tumor cells and TME, thereby affecting tumor development. Tumor-derived exosomal miRNAs induce matrix reprogramming in TME, creating a microenvironment that is conducive to tumor growth, metastasis, immune escape and chemotherapy resistance. In this review, we updated the role of exosomal miRNAs in the process of TME reshaping.