MicroRNA‐425‐5p promotes breast cancer cell growth by inducing PI3K/AKT signaling

MicroRNA-425: A Pivotal Regulator Participating in Tumorigenesis of Human Cancers

MicroRNAs (miRNAs) are small single-stranded regulatory RNAs that are shown to be dysregulated in a wide array of human cancers. MiRNAs play critical roles in cancer progression and function as either oncogenes or tumor suppressors through modulating various target genes. Therefore, they possess great potential as diagnostic and therapeutic targets for cancer detection and treatment. In particular, recent studies have illustrated that miR-425 is also dysregulated in various human malignancies and plays a fundamental role in cancer initiation and progression. miR-425 has been reported to function as a dual-role miRNA participating in the regulation of cellular processes, including metastasis, invasion, and cell proliferation by modulating multiple signaling pathways, such as TGF-β, Wnt, and P13K/AKT pathways. Therefore, regarding recent researches showing the high therapeutic potential of miR-425, in this review, we have noted the impact of its dysregulation on signaling pathways and various aspects of tumorigenesis in a variety of human cancers.

LINC00969 inhibits proliferation with metastasis of breast cancer by regulating phosphorylation of PI3K/AKT and ILP2 expression through HOXD8

Background

Breast cancer (BC) is a malignancy that is inadequately treated and poses a significant global health threat to females. The aberrant expression of long noncoding RNAs (lncRNAs) acts as a complex with a precise regulatory role in BC progression. LINC00969 has been linked to pyroptotic cell death and resistance to gefitinib in lung cancer cells. However, the precise function and regulatory mechanisms of LINC00969 in BC remain largely unexplored.

Methods

Cell proliferation, migration, and invasion of BC cells were evaluated using CCK-8 and Transwell assays. Western blotting was employed to analyze the protein expression levels of HOXD8, ILP2, PI3K, t-AKT, and p-AKT.

Results

LINC00969 was drastically reduced in BC tissues LINC00969 overexpression markedly suppressed proliferation, migration, and invasion, and blocked PI3K and p-AKT protein expression in MCF-7 cells. Activation of the PI3K/AKT pathway reversed the suppressive effect of LINC0096 overexpression on the proliferation, migration, and invasion of MCF-7 cells. Moreover, LINC00969 overexpression enhanced HOXD8 and blocked ILP2 protein expression in MCF-7 cells. In contrast, activating the PI3K/AKT pathway had no effect on HOXD8 and blocked ILP2 protein expression in MCF-7 cells overexpressing LINC00969. HOXD8 knockdown enhanced ILP2, PI3K, and p-AKT protein expression, and the proliferation, migration, and invasion of MCF-7 cells co-transfected with si-HOXD8 and ov-LINC00969. LINC00969 regulated HOXD8 via binding to miR-425-5p.

Conclusion

LINC00969 inhibits the proliferation and metastasis of BC cells by regulating PI3K/AKT phosphorylation through HOXD8/ILP2.

Circular RNA mediated gene regulation in human breast cancer: A bioinformatics analysis

Circular RNAs (circRNAs) are a new acknowledged class of RNAs that has been shown to play a major role in several biological functions both in physiological and pathological conditions, operating as critical part of regulatory processes, like competing endogenous RNA (ceRNA) networks. The ceRNA hypothesis is a recently discovered molecular mechanism that adds a new key layer of post-transcriptional regulation, whereby various types of RNAs can reciprocally influence each other's expression competing for binding the same pool of microRNAs, even affecting disease development. In this study, we build a network of circRNA-miRNA-mRNA interactions in human breast cancer, called CERNOMA, that is a bipartite graph with one class of nodes corresponding to differentially expressed miRNAs (DEMs) and the other one corresponding to differentially expressed circRNAs (DEC) and mRNAs (DEGs). A link between a DEC (or DEG) and DEM is placed if it is predicted to be a target of the DEM and shows an opposite expression level trend with respect to the DEM. Within the CERNOMA, we highlighted an interesting deregulated circRNA-miRNA-mRNA triplet, including the up-regulated hsa_circRNA_102908 (BRCA1 associated RING domain 1), the down-regulated miR-410-3p, and the up-regulated ESM1, whose overexpression has been already shown to promote tumor dissemination and metastasis in breast cancer.

Diverse Functions of MiR-425 in Human Cancer

miRNAs are a type of small endogenous noncoding RNA composed of 20-22 nucleotides that can regulate gene expression by targeting the 3' untranslated region of mRNA. Many investigations have discovered that miRNAs have a role in the development and progression of human cancer. Several aspects of tumor development are affected by miR-425, including growth, apoptosis, invasion, migration, epithelial-mesenchymal transition, and drug resistance. In this article, we discuss the properties and research development of miR-425, focusing on the regulation and function of miR-425 in various cancers. Furthermore, we discuss the clinical implications of miR-425. This review may broaden our horizon for better understanding the role of miR-425 as biomarkers and therapeutic targets in human cancer.

Breast cancer tumor microenvironment affects Treg/IL-17-producing Treg/Th17 cell axis: Molecular and therapeutic perspectives

The tumor microenvironment (TME) comprises a variety of immune cells, among which T cells exert a prominent axial role in tumor development or anti-tumor responses in patients with breast cancer (BC). High or low levels of anti-inflammatory cytokines, such as transforming growth factor β, in the absence or presence of proinflammatory cytokines, such as interleukin-6 (IL-6), delineate the fate of T cells toward either regulatory T (Treg) or T helper 17 (Th17) cells, respectively. The transitional state of RORγt⁺Foxp3⁺ Treg (IL-17-producing Treg) resides in the middle of this reciprocal polarization, which is known as Treg/IL-17-producing Treg/Th17 cell axis. TME secretome, including microRNAs, cytokines, and extracellular vesicles, can significantly affect this axis. Furthermore, immune checkpoint inhibitors may be used to reconstruct immune cells; however, some of these novel therapies may favor tumor development. Therefore, understanding secretory and cell-associated factors involved in their differentiation or polarization and functions may be targeted for BC management. This review discusses microRNAs, cytokines, and extracellular vesicles (as secretome), as well as transcription factors and immune checkpoints (as cell-associated factors), which influence the Treg/IL-17-producing Treg/Th17 cell axis in BC. Furthermore, approved or ongoing clinical trials related to the modulation of this axis in the TME of BC are described to broaden new horizons of promising therapeutic approaches.

Role of epigallocatechin-3- gallate in the regulation of known and novel microRNAs in breast carcinoma cells

Breast cancer comprises 30% of all cancer cases among the world’s women population. MicroRNAs are small, endogenous, non-coding RNAs that regulate cell proliferating and apoptotic pathways by modulating expressions of related genes. Phytochemicals like epigallocatechin-3-gallate (EGCG) are known to have a chemotherapeutic effect on cancer often through the regulation of microRNAs. The aim is to find out the key known and novel miRNAs, which are controlled by EGCG in breast cancer cell line MDA-MB-231. Next-generation sequencing (NGS) revealed 1,258 known and 330 novel miRNAs from untreated and 83 μM EGCG (IC50 value of EGCG) treated cells. EGCG modulated 873 known and 47 novel miRNAs in the control vs. treated sample. The hypothesis of EGCG being a great modulator of miRNAs that significantly control important cancer-causing pathways has been established by analyzing with Kyoto Encyclopedia of Genes and Genomes (KEGG) and Protein Analysis Through Evolutionary Relationships (PANTHER) database. Validation of known and novel miRNA expression differences in untreated vs. treated cells was done using qPCR. From this study, a few notable miRNAs were distinguished that can be used as diagnostics as well as prognostic markers for breast cancer.

Crosstalk between miRNA and PI3K/AKT/mTOR signaling pathway in cancer

Phosphoinositide-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important proliferative signaling pathways with critical undeniable function in various aspects of cancer initiation/progression, including proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. On the other hand, numerous genetic alterations in the key genes involved in the PI3K/AKT/mTOR signaling pathway have been identified in multiple solid and hematological tumors. In addition, accumulating recent evidences have demonstrated a reciprocal interaction between this signaling pathway and microRNAs, a large group of small non-coding RNAs. Therefore, in this review, it was attempted to discuss about the interaction between key components of PI3K/AKT/mTOR signaling pathway with various miRNAs and their importance in cancer biology.

Small molecules with huge impacts: the role of miRNA-regulated PI3K pathway in human malignancies

Along with evolution, a considerable number of signaling cascades have evolved within cells to meet their multifaceted needs. Among transmitting molecules, phosphoinositide 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR) have teamed up to build a signaling axis that effectively regulates various cellular processes including cell proliferation and migration. Given the extensive output of the PI3K/Akt/mTOR signaling axis, its aberrancy could subsequently lead to the formation of a wide range of human cancers spanning from hematologic malignancies to different types of solid tumors. Despite the high frequency of the PI3K pathway over-activation in most malignancies, mutations in the DNA sequence are not equally common. Such incompatibility sheds light on the possible effects of post-translational modification mechanisms that may take control of this pathway, some of the most important ones of which are through microRNAs (miRNAs or miRs). The present review is designed to take off the veil from the regulatory role of these small non-coding RNAs on the PI3K/Akt/mTOR signaling axis in carcinogenesis.

MiR-425-5p accelerated the proliferation, migration, and invasion of ovarian cancer cells via targeting AFF4

Background

Accumulating data have established that microRNAs (miRNAs) play significant regulatory roles in the carcinogenesis and progression of ovarian cancer (OC). MiR-425-5p was reported to function in various tumors. However, the roles and underlying mechanism of miR-425-5p involvement in OC development and progression are unclear.

Methods

A comprehensive strategy of data mining, computational biology, and real-time polymerase chain reaction was employed to identify the involvement of miR-425-5p in OC progression. The effect of miR-425-5p on the proliferation, migration, and invasion of OC cells was determined using Cell Counting Kit-8, wound-healing, and Matrigel invasion assays, respectively. Luciferase assay was performed to evaluate the interactions between miR-425-5p and MAGI2-AS3 or AFF4.

Results

miR-425-5p was significantly up-regulated in OC tissues and cells. The luciferase reporter assay revealed that miR-425-5p was negatively regulated by MAGI2-AS3. Silencing miR-425-5p inhibited the proliferation, migration, and invasion of OC cells in vitro. Bioinformatics analysis and luciferase reporter assay revealed that AFF4 was the target gene of miR-425-5p. Moreover, AFF4 expression was significantly decreased in OC and was closely related to the good prognosis of patients with OC. AFF4 overexpression inhibited the proliferation, migration, and invasion of OC cells in vitro. By contrast, silencing AFF4 promoted the proliferation, migration, and invasion of OC cells in vitro. Finally, AFF4 suppression rescued the inhibitory effect of silencing miR-425-5p on the proliferation, migration, and invasion of OC cells.

Conclusion

To the best our knowledge, this is the first study to demonstrate that miR-425-5p overexpression in OC is negatively regulated by MAGI2-AS3. Moreover, miR-425-5p promotes the proliferation, migration, and invasion of OC cells by targeting AFF4, suggesting that miR-425-5p/AFF4 signaling pathway represented a novel therapeutic target for patients with OC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00894-x.

LncRNA-MSC-AS1 inhibits the ovarian cancer progression by targeting miR-425-5p

BACKGROUND

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) were reported to be aberrantly expressed and related to the pathogenesis of ovarian cancer. However, the role and regulatory mechanism of MSC-AS1 in ovarian cancer has yet to be fully elucidated.

METHODS

Expression of lncRNA MSC-AS1 (MSC-AS1) and microRNA-425-5p (miR-425-5p) in the ovarian cancer tissue samples and cell lines was examined by quantitative real-time polymerase chain reaction (qRT-PCR). The functions of MSC-AS1 on ovarian cancer cell proliferation, cell cycle and apoptosis were determined using MTT, colony formation and flow cytometry analyses. The protein expression levels were evaluated using western blot assay. The targeting relationship MSC-AS1 and miR-425-5p was verified via dual-luciferase reporter assay.

RESULTS

MSC-AS1 expression level was lowly expressed, while miR-425-5p level was highly in ovarian cancer tissues and cells. Elevation of MSC-AS1 has the ability to significantly inhibit cell proliferation and facilitate cell apoptosis in SKOV3 and A2780 cells. Moreover, MSC-AS1 targeted and negatively modulated miR-425-5p. MiR-425-5p up-regulation has been proved to partially reverse the tumor suppressive function of MSC-AS1 overexpression CONCLUSION: MSC-AS1 sponged miR-425-5p to inhibit the ovarian cancer progression. These findings may provide a promising therapeutic target for the treatment of ovarian cancer.

MicroRNAs as Emerging Regulators of Signaling in the Tumor Microenvironment

A myriad of signaling molecules in a heuristic network of the tumor microenvironment (TME) pose a challenge and an opportunity for novel therapeutic target identification in human cancers. MicroRNAs (miRs), due to their ability to affect signaling pathways at various levels, take a prominent space in the quest of novel cancer therapeutics. The role of miRs in cancer initiation, progression, as well as in chemoresistance, is being increasingly investigated. The canonical function of miRs is to target mRNAs for post-transcriptional gene silencing, which has a great implication in first-order regulation of signaling pathways. However, several reports suggest that miRs also perform non-canonical functions, partly due to their characteristic non-coding small RNA nature. Examples emerge when they act as ligands for toll-like receptors or perform second-order functions, e.g., to regulate protein translation and interactions. This review is a compendium of recent advancements in understanding the role of miRs in cancer signaling and focuses on the role of miRs as novel regulators of the signaling pathway in the TME.

Role of regulatory miRNAs of the PI3K/AKT signaling pathway in the pathogenesis of breast cancer

Breast cancer is one of the most common tumors in women. Current data indicate that the overexpression of some microRNAs (miRNAs) is associated with breast cancer, in relation to stage, tumor size and potential for metastasis. Some studies have reported that miRNAs have critical roles in cellular processes implicated in breast cancer cell growth, migration and metastasis by targeting the PI3K/AKT oncogenic signaling pathway. Therefore, identifying novel regulatory miRNAs for this oncogenic pathway and discovery of their related target genes may represent a promising therapeutic approach for breast cancer therapy. This review highlights the recent findings about the potential role of PI3K/AKT signaling regulatory miRNAs in breast cancer tumorigenesis.