miR‑802 inhibits the epithelial‑mesenchymal transition, migration and invasion of cervical cancer by regulating BTF3

The m6A methyltransferase RBM15 affects tumor cell stemness and progression of cervical cancer by regulating the stability of lncRNA HEIH

Cervical cancer (CC), as a common female malignant tumor in the world, is an important risk factor endangering women's health worldwide. The purpose of this study was to investigate the role of RBM15 in CC. The TCGA database was used to screen differentially expressed m6A genes in normal and tumor tissues. QRT-PCR was used to quantify HEIH, miR-802, EGFR, cell stemness, and epithelial-mesenchymal transition (EMT)-related genes. The interaction between HEIH and miR-802 was verified by dual-luciferase reporter assay and RIP assay. The occurrence of tumor cells after different treatments was detected by CCK-8, transwell and EdU staining. BALB/c nude mice were used to examine the effects of different treatments on tumor growth and cell stemness in vivo. RBM15 was upregulated in tumor tissues and cells. M6A was highly enriched in HEIH and enhances its RNA stability. HEIH acts as an oncogenic lncRNA to promote CC cell proliferation, migration and tumor growth. Mechanistically, HEIH regulates tumor cell stemness and promotes the proliferation and migration of CC cells by competitively adsorbing miR-802 and up-regulating the expression of EGFR. In short, our data shown that the m6A methyltransferase RBM15 could affect tumor cell proliferation, metastasis and cell stemness by stabilizing HEIH expression.

MicroRNAs, long non-coding RNAs, and circular RNAs and gynecological cancers: focus on metastasis

Gynecologic cancer is a significant cause of death in women worldwide, with cervical cancer, ovarian cancer, and endometrial cancer being among the most well-known types. The initiation and progression of gynecologic cancers involve a variety of biological functions, including angiogenesis and metastasis-given that death mostly occurs from metastatic tumors that have invaded the surrounding tissues. Therefore, understanding the molecular pathways underlying gynecologic cancer metastasis is critical for enhancing patient survival and outcomes. Recent research has revealed the contribution of numerous non-coding RNAs (ncRNAs) to metastasis and invasion of gynecologic cancer by affecting specific cellular pathways. This review focuses on three types of gynecologic cancer (ovarian, endometrial, and cervical) and three kinds of ncRNAs (long non-coding RNAs, microRNAs, and circular RNAs). We summarize the detailed role of non-coding RNAs in the different pathways and molecular interactions involved in the invasion and metastasis of these cancers.

Kidney microRNA Expression Pattern in Type 2 Diabetic Nephropathy in BTBR Ob/Ob Mice

Diabetic nephropathy (DN) is the main leading cause of chronic kidney disease worldwide. Although remarkable therapeutic advances have been made during the last few years, there still exists a high residual risk of disease progression to end-stage renal failure. To further understand the pathogenesis of tissue injury in this disease, by means of the Next-Generation Sequencing, we have studied the microRNA (miRNA) differential expression pattern in kidneys of Black and Tan Brachyury (BTBR) ob/ob (leptin deficiency mutation) mouse. This experimental model of type 2 diabetes and obesity recapitulates the key histopathological features described in advanced human DN and therefore can provide potential useful translational information. The miRNA-seq analysis, performed in the renal cortex of 22-week-old BTBR ob/ob mice, pointed out a set of 99 miRNAs significantly increased compared to non-diabetic, non-obese control mice of the same age, whereas no miRNAs were significantly decreased. Among them, miR-802, miR-34a, miR-132, miR-101a, and mir-379 were the most upregulated ones in diabetic kidneys. The in silico prediction of potential targets for the 99 miRNAs highlighted inflammatory and immune processes, as the most relevant pathways, emphasizing the importance of inflammation in the pathogenesis of kidney damage associated to diabetes. Other identified top canonical pathways were adipogenesis (related with ectopic fatty accumulation), necroptosis (an inflammatory and regulated form of cell death), and epithelial-to-mesenchymal transition, the latter supporting the importance of tubular cell phenotype changes in the pathogenesis of DN. These findings could facilitate a better understanding of this complex disease and potentially open new avenues for the design of novel therapeutic approaches to DN.

The novel circ_0084904/miR-802/MAL2 axis promotes the development of cervical cancer

Circular RNAs (circRNAs) have been identified as critical regulators in human cancers, including cervical cancer (CC). However, the precise action of circ_0084904 in cervical carcinogenesis remains to be elucidated. The levels of circ_0084904, microRNA (miR)-802, and Mal, T cell differentiation protein 2 (MAL2) were checked by quantitative real-time PCR (qRT-PCR) or western blot. Ribonuclease R (RNase R) and subcellular localization assays were used to detect the stability and localization of circ_0084904, respectively. Cell colony formation ability was assessed by colony formation assay. Cell cycle and apoptosis were detected by flow cytometry. Cell migration and invasion abilities were gauged by transwell assay. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were applied to determine the direct relationship between miR-802 and circ_0084904 or MAL2. The xenograft experiments were performed to evaluate the role of circ_0084904 in tumor growth in vivo. Circ_0084904 was markedly up-regulated in CC tissues and cell lines. Silencing endogenous circ_0084904 impeded cell colony formation, cell cycle progression, migration, invasion, epithelial-mesenchymal transition (EMT), and promoted apoptosis in vitro, as well as diminished tumor growth in vivo. Mechanistically, circ_0084904 targeted miR-802, and the effects of circ_0084904 silencing were mediated by miR-802. MAL2 was directly targeted and inhibited by miR-802, and MAL2 was a functional target of miR-802. Moreover, circ_0084904 modulated MAL2 expression via miR-802. Our study identified circ_0084904 as a novel oncogenic driver in CC depending on the modulation of the miR-802/MAL2 axis, establishing the notion that silencing of circ_0084904 might represent a promising targeted therapy for CC.

Dysfunction of miR-802 in tumors

Recent studies have shown that miR-802 is abnormally expressed in many tumors. miR-802 is expressed at low levels in tissues and cells of gastric cancer, colorectal cancer, breast cancer, cervical cancer, epithelial ovarian cancer, tongue squamous cell carcinoma, oral squamous cell carcinoma, esophageal squamous cell carcinoma, laryngeal squamous cell carcinoma, and melanoma. In contrast, miR-802 is overexpressed in hepatocellular carcinoma, bladder urothelial cancer, osteosarcoma, and cholesteatoma tissue cells. It should be noted that the results of studies on the expression of miR-802 in pancreatic cancer, prostate cancer, and lung cancer are inconsistent. Current studies have found that miR-802 can target and regulate genes in different tumors, and affect the regulation of the Wnt signaling pathway, EMT signaling pathway, PI3K/AKT signaling pathway, ERK signaling pathway, and Hedgehog signaling pathway. At the same time, miR-802 is regulated by the endogenous competition of four ceRNAs, including circDONSON, IGFL2-AS1, MIR155HG, and MIR4435-2HG. This article reviews the abnormal expression of miR-802 in a variety of tumors, expounds the mechanism by which miR-802 affects tumor progression by regulating different target genes, and elaborates the network of miR-802-related ceRNAs. We also summarized the limitations of miR-802 research and looked forward to the potential application of miR-802 in the diagnosis and prognosis of tumors.

Molecular Characterization of the Oncogene BTF3 and Its Targets in Colorectal Cancer

Colorectal cancer (CRC) is one of the most commonly diagnosed and leading causes of cancer mortality worldwide, and the prognosis of patients with CRC remains unsatisfactory. Basic transcription factor 3 (BTF3) is an oncogene and hazardous prognosticator in CRC. Although two distinct functional mechanisms of BTF3 in different cancer types have been reported, its role in CRC is still unclear. In this study, we aimed to molecularly characterize the oncogene BTF3 and its targets in CRC. Here, we first identified the transcriptional targets of BTF3 by applying combined RNA-Seq and ChIP-Seq analysis, identifying CHD1L as a transcriptional target of BTF3. Thereafter, we conducted immunoprecipitation (IP)-MS and E3 ubiquitin ligase analysis to identify potential interacting targets of BTF3 as a subunit of the nascent-polypeptide-associated complex (NAC). The analysis revealed that BTF3 might also inhibit E3 ubiquitin ligase HERC2-mediated p53 degradation. Finally, miRNAs targeting BTF3 were predicted and validated. Decreased miR-497-5p expression is responsible for higher levels of BTF3 post-transcriptionally. Collectively, we concluded that BTF3 is an oncogene, and there may exist a transcription factor and NAC-related proteolysis mechanism in CRC. This study provides a comprehensive basis for understanding the oncogenic mechanisms of BTF3 in CRC.