Long non-coding RNA RPPH1 promotes the proliferation, invasion and migration of human acute myeloid leukemia cells through down-regulating miR-330-5p expression

Hypoxia induced cellular and exosomal RPPH1 promotes breast cancer angiogenesis and metastasis through stabilizing the IGF2BP2/FGFR2 axis

Metastasis is the major cause of breast cancer mortality, with angiogenesis and tumor-released exosomes playing key roles. However, the communication between breast cancer cells and endothelial cells and its role in tumor metastasis remains unclear. Here, we characterize a long noncoding RNA, RPPH1, which is upregulated in breast cancer tissues and positively associated with poor prognosis. Hypoxia microenvironment upregulates the expression of RPPH1 in breast cancer cells, and promotes its packaging into exosomes through hnRNPA1, leading to the maintenance of stemness and aggressive traits in cancer cells and angiogenesis in endothelial cells. The function of cellular and exosomal RPPH1 was confirmed in the MMTV-PyMT mouse model, in which ASO-RPPH1 therapy effectively inhibited tumor progression and metastasis. Mechanistically, RPPH1 protects IGF2BP2 from ubiquitination-induced degradation, stabilizes N6-methyladenosine (m6A)-modified FGFR2 mRNA, and activates the PI3K/AKT pathway. Our research unveils the role of RPPH1 in breast cancer metastasis and highlights its potential as a therapeutic target.

The Pol III transcriptome: Basic features, recurrent patterns, and emerging roles in cancer

The RNA polymerase III (Pol III) transcriptome is universally comprised of short, highly structured noncoding RNA (ncRNA). Through RNA-protein interactions, the Pol III transcriptome actuates functional activities ranging from nuclear gene regulation (7SK), splicing (U6, U6atac), and RNA maturation and stability (RMRP, RPPH1, Y RNA), to cytoplasmic protein targeting (7SL) and translation (tRNA, 5S rRNA). In higher eukaryotes, the Pol III transcriptome has expanded to include additional, recently evolved ncRNA species that effectively broaden the footprint of Pol III transcription to additional cellular activities. Newly evolved ncRNAs function as riboregulators of autophagy (vault), immune signaling cascades (nc886), and translation (Alu, BC200, snaR). Notably, upregulation of Pol III transcription is frequently observed in cancer, and multiple ncRNA species are linked to both cancer progression and poor survival outcomes among cancer patients. In this review, we outline the basic features and functions of the Pol III transcriptome, and the evidence for dysregulation and dysfunction for each ncRNA in cancer. When taken together, recurrent patterns emerge, ranging from shared functional motifs that include molecular scaffolding and protein sequestration, overlapping protein interactions, and immunostimulatory activities, to the biogenesis of analogous small RNA fragments and noncanonical miRNAs, augmenting the function of the Pol III transcriptome and further broadening its role in cancer. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Processing of Small RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Zrsr2 and functional U12-dependent spliceosome are necessary for follicular development

ZRSR2 is a splicing factor involved in recognition of 3'-intron splice sites that is frequently mutated in myeloid malignancies and several tumors; however, the role of mutations of Zrsr2 in other tissues has not been analyzed. To explore the biological role of ZRSR2, we generated three Zrsr2 mutant mouse lines. All Zrsr2 mutant lines exhibited blood cell anomalies, and in two lines, oogenesis was blocked at the secondary follicle stage. RNA-seq of Zrsr2 mu secondary follicles showed aberrations in gene expression and showed altered alternative splicing (AS) events involving enrichment of U12-type intron retention (IR), supporting the functional Zrsr2 action in minor spliceosomes. IR events were preferentially associated with centriole replication, protein phosphorylation, and DNA damage checkpoint. Notably, we found alterations in AS events of 50 meiotic genes. These results indicate that ZRSR2 mutations alter splicing mainly in U12-type introns, which may affect peripheral blood cells, and impede oogenesis and female fertility.

MiR-192-5p-Modified Tumor-Associated Macrophages-Derived Exosome Suppressed Endometrial Cancer Progression Through Targeting IRAK1/NF-κB Signaling

Tumor-associated macrophages (TAMs) are a major regulator in the development of endometrial cancer (EC). It was indicated that TAMs could crosstalk with cancer cells via transferring exosomes which carrying microRNAs (miRNAs). Firstly, we found that TAMs could promote the epithelial-mesenchymal transition (EMT) of EC cells and inhibit its apoptosis. Next, we further found that TAMs regulated the EMT and apoptosis of EC cells through transferring exosomes into EC cells. Then, lowly expressed miR-192-5p in TAMs-derived exosomes was proved. Moreover, our data demonstrated that upregulation of miR-192-5p in TAMs-derived exosomes could significantly promote the apoptosis of EC cells and impede its EMT. IRAK1 was proved to be a downstream target of miR-192-5p. Importantly, we indicated that miR-192-5p-overexpressed TAMs-derived exosomes regulated the EC cells apoptosis and EMT through inhibiting IRAK1/NF-κB signaling pathway. In addition, we also revealed that overexpression of miR-192-5p in TAMs-derived exosomes obviously limits the growth of tumors. Overall, in TAMs-derived exosomes, our data demonstrated that overexpression of miR-192-5p could effectively suppress the progression of EC. Our data provid a new target for EC treatment.

Tumor Microenvironmental Competitive Endogenous RNA Network and Immune Cells Act as Robust Prognostic Predictor of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is malignant hematologic tumors with frequent recurrence and cause high mortality. Its fate is determined by abnormal intracellular competitive endogenous RNA (ceRNA) network and extracellular tumor microenvironment (TME). This study aims to build a ceRNA network related to AML TME to explore new prognostic and therapeutic targets. The RNA expression data of AML were obtained from The Cancer Genome Atlas (TCGA) database. First, we used the ESTIMATE algorithm to calculate the immune cells and stromal cells infiltration scores in the TME and found that all scores were highly correlated with AML’s prognostic characteristics. Subsequently, differentially expressed mRNAs and lncRNAs between high and low score groups were identified to construct a TME-related ceRNA network. Further, the Cox-lasso survival model was employed to screen out the hub prognostic ceRNA network composed of two mRNAs (EPB41L3, COL2A1), three miRNAs (hsa-mir-26a-5p, hsa-mir-148b-3p, hsa-mir-148a-3p), and two lncRNAs (CYP1B1-AS1, C9orf106), and construct nomograms. Finally, we used CIBERSORT algorithm and Kaplan-Meier survival analysis to identify the prognostic TME immune cells and found that naive B cells, M2-type macrophages, and helper follicular T cells were related to prognosis, and the hub ceRNAs were highly correlated with immune cell infiltration. This study provided a new perspective to elucidate how TME regulates AML process and put forward the new therapy strategies combining targeting tumor cells with disintegrating TME.

Knockdown of circ_0003204 alleviates oxidative low-density lipoprotein-induced human umbilical vein endothelial cells injury: Circulating RNAs could explain atherosclerosis disease progression

Atherosclerosis (AS) is a serious cardiovascular disease. Circular RNAs (circRNAs) play an important role in the progression of many diseases, including AS. However, the role of circ_0003204 in AS is not clear. Oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs) were used to construct an AS cell model in vitro. Cell viability was assessed using cell counting kit 8 (CCK8) assay. Flow cytometry and caspase-3 activity were used to measure cell apoptosis. The contents of inflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA). Oxidative stress marker expression and cell injury marker activity were detected by their corresponding Assay Kits. Besides, the expression levels of circ_0003204, miR-330-5p, and toll-like receptor 4 (TLR4) were tested by real-time polymerase chain reaction (qPCR). The interaction between miR-330-5p and circ_0003204 or TLR4 was examined by dual-luciferase reporter assay and RNA pull-down assay. Western blot (WB) analysis was used to determine the levels of TLR4 protein and nuclear factor-kappa B (NF-κB) signaling pathway-related protein. Our data suggested that ox-LDL could suppress viability and promote apoptosis, inflammatory response, and oxidative stress in HUVECs. circ_0003204 was highly expressed in ox-LDL-induced HUVECs, and its silencing could inhibit ox-LDL-induced HUVECs injury. miR-330-5p could be sponged by circ_0003204, and its inhibitor could reverse the inhibition effect of silenced circ_0003204 on ox-LDL-induced HUVECs injury. Further, TLR4 could be targeted by miR-330-5p, and its overexpression could invert the suppression effect of miR-330-5p on ox-LDL-induced HUVECs injury. The activity of the NF-κB signaling pathway was regulated by the circ_0003204/miR-330-5p/TLR4 axis. Our results indicated that circ_0003204 silencing could alleviate ox-LDL-induced HUVECs injury, suggesting that circ_0003204 might be a novel target for AS treatment.

Non-coding RNAs regulation of macrophage polarization in cancer

Noncoding RNA (ncRNA) transcripts that did not code proteins but regulate their functions were extensively studied for the last two decades and the plethora of discoveries have instigated scientists to investigate their dynamic roles in several diseases especially in cancer. However, there is much more to learn about the role of ncRNAs as drivers of malignant cell evolution in relation to macrophage polarization in the tumor microenvironment. At the initial stage of tumor development, macrophages have an important role in directing Go/No-go decisions to the promotion of tumor growth, immunosuppression, and angiogenesis. Tumor-associated macrophages behave differently as they are predominantly induced to be polarized into M2, a pro-tumorigenic type when recruited with the tumor tissue and thereby favoring the tumorigenesis. Polarization of macrophages into M1 or M2 subtypes plays a vital role in regulating tumor progression, metastasis, and clinical outcome, highlighting the importance of studying the factors driving this process. A substantial number of studies have demonstrated that ncRNAs are involved in the macrophage polarization based on their ability to drive M1 or M2 polarization and in this review we have described their functions and categorized them into oncogenes, tumor suppressors, Juggling tumor suppressors, and Juggling oncogenes.

lncRNA RPPH1 promotes non-small cell lung cancer progression through the miR-326/WNT2B axis

Long non-coding RNAs (lncRNAs) serve important regulatory roles in human tumors. The aim of the present study was to examine the role of ribonuclease P RNA component H1 (RPPH1) in non-small cell lung cancer (NSCLC). RPPH1 expression was assessed in datasets from The Cancer Genome Atlas, as well as lung cancer cell lines and patients with NSCLC. RPPH1 was significantly upregulated in NSCLC cell lines, compared with a normal lung epithelial cell line. Moreover, high RPPH1 expression was associated with poor overall survival and disease progression. RPPH1 was knocked down in A549 and H1299 cells using short hairpin (sh) RNA constructs, and the expressions of target genes and proteins were determined by reverse transcription-quantitative PCR and western blotting. Cell invasion potential was also determined using Transwell Matrigel assays. Compared with the negative control, RPPH1 silencing significantly reduced the number of invading cells, increased E-cadherin expression and reduced vimentin protein expression. Cell resistance to cisplatin/cis-diamminedichloridoplatinum (CDDP) was also evaluated using Cell Counting Kit-8 and colony formation assays. RPPH1 overexpression increased the resistance of A549 and H1299 cells to CDDP. Moreover, the potential interactions between RPPH1, microRNA (miR)-326 and Wnt family member 2B (WNT2B) were investigated using luciferase reporter assays and co-transfection experiments. MiR-326 expression was directly inhibited by RPPH1. In A549 cells co-transfected with shRPPH1 and miR-326 inhibitor, the invading cell number significantly increased compared with cells transfected with shRPPH1 alone. In addition, E-cadherin expression levels were reduced, and vimentin was upregulated. MiR-326 overexpression partially reduced the resistance of A549 cells to CDDP induced by RPPH1 overexpression. WNT2B expression was directly suppressed using miR-326. A549 cells co-transfected with a miR-326 mimic and a WNT2B overexpression vector demonstrated increased invasion potential, reduced E-cadherin and increased vimentin protein expression levels, compared with cells transfected with the mimic alone. miR-326 overexpression reduced CDDP resistance in A549 cells. However, co-transfection with WNT2B partially enhanced CDDP resistance, compared with the mimic alone. In conclusion, RPPH1 promoted NSCLC progression and lung cancer cell resistance to CDDP through miR-326 and WNT2B.

Identification of circRNA-lncRNA-miRNA-mRNA Competitive Endogenous RNA Network as Novel Prognostic Markers for Acute Myeloid Leukemia

Background: Acute myeloid leukemia (AML) is one of the most common malignant and aggressive hematologic tumors, and its pathogenesis is associated with abnormal post-transcriptional regulation. Unbalanced competitive endogenous RNA (ceRNA) promotes tumorigenesis and progression, and greatly contributes to tumor risk classification and prognosis. However, the comprehensive analysis of the circular RNA (circRNA)-long non-coding RNA (lncRNA)-miRNA-mRNA ceRNA network in the prognosis of AML is still rarely reported. Method: We obtained transcriptome data of AML and normal samples from The Cancer Genome Atlas (TCGA), Genotype-tissue Expression (GTEx), and Gene Expression Omnibus (GEO) databases, and identified differentially expressed (DE) mRNAs, lncRNAs, and circRNAs. Then, the targeting relationships among lncRNA-miRNA, circRNA-miRNA, and miRNA-mRNA were predicted, and the survival related hub mRNAs were further screened by univariate and multivariate Cox proportional hazard regression. Finally, the AML prognostic circRNA-lncRNA-miRNA-mRNA ceRNA regulatory network was established. Results: We identified prognostic 6 hub mRNAs (TM6SF1, ZMAT1, MANSC1, PYCARD, SLC38A1, and LRRC4) through Cox regression model, and divided the AML samples into high and low risk groups according to the risk score obtained by multivariate Cox regression. Survival analysis verified that the survival rate of the high-risk group was significantly reduced (p < 0.0001). The prognostic ceRNA network of 6 circRNAs, 32 lncRNAs, 8 miRNAs, and 6 mRNAs was established according to the targeting relationship between 6 hub mRNAs and other RNAs. Conclusion: In this study, ceRNA network jointly participated by circRNAs and lncRNAs was established for the first time. It comprehensively elucidated the post-transcriptional regulatory mechanism of AML, and identified novel AML prognostic biomarkers, which has important guiding significance for the clinical diagnosis, treatment, and further scientific research of AML.