MicroRNA-188-5p promotes apoptosis and inhibits cell proliferation of breast cancer cells via the MAPK signaling pathway by targeting Rap2c

Exploring the time-dependent regulatory potential of microRNAs in breast cancer cells treated with proteasome inhibitors

PURPOSE

Breast cancer (BrCa) is a predominant type of cancer with a disparate molecular nature. MicroRNAs (miRNAs) have emerged as promising key players in the regulation of pathological processes in BrCa. Proteasome inhibitors (PIs) emerged as promising anticancer agents for several human malignancies, including BrCa, inhibiting the function of the proteasome. Aiming to shed light on the miRNA regulatory effect in BrCa after treatment with PIs, we used two PIs, namely bortezomib and carfilzomib.

MATERIALS AND METHODS

Four BrCa cell lines of distinct molecular subtypes were treated with these PIs. Cell viability and IC50 concentrations were determined. Total RNA was extracted, polyadenylated, and reversely transcribed. Next, the levels of specific miRNAs with a significant role in BrCa were determined using relative quantification, and their regulatory effect was assessed.

RESULTS

High heterogeneity was discovered in the levels of miRNAs in the four cell lines, after treatment. The miRNA levels fluctuate with distinct patterns, in 24, 48, or 72 hours. Interestingly, miR-1-3p, miR-421-3p, and miR-765-3p appear as key molecules, as they were found deregulated, in almost all combinations of cell lines and PIs. In the SK-BR-3 cell line, the majority of the miRNAs were significantly downregulated in treated compared to untreated cells, with miR-21-5p being the only one upregulated. Finally, various significant biological processes, molecular functions, and pathways were predicted to be affected.

CONCLUSIONS

The diversity of pathways predicted to be affected by the diversity in miRNA expression after treatment with PIs paves the way for the recognition of new regulatory axes in BrCa.

The crosstalk between miRNAs and signaling pathways in human cancers: Potential therapeutic implications

MicroRNAs (miRNAs) are increasingly recognized as central players in the regulation of eukaryotic physiological processes. These small double stranded RNA molecules have emerged as pivotal regulators in the intricate network of cellular signaling pathways, playing significant roles in the development and progression of human cancers. The central theme in miRNA-mediated regulation of signaling pathways involves their ability to target and modulate the expression of pathway components. Aberrant expression of miRNAs can either promote or suppress key signaling events, influencing critical cellular processes such as proliferation, apoptosis, angiogenesis, and metastasis. For example, oncogenic miRNAs often promote cancer progression by targeting tumor suppressors or negative regulators of signaling pathways, thereby enhancing pathway activity. Conversely, tumor-suppressive miRNAs frequently inhibit oncogenic signaling by targeting key components within these pathways. This complex regulatory crosstalk underscores the significance of miRNAs as central players in shaping the signaling landscape of cancer cells. Furthermore, the therapeutic implications of targeting miRNAs in cancer are substantial. miRNAs can be manipulated to restore normal signaling pathway activity, offering a potential avenue for precision medicine. The development of miRNA-based therapeutics, including synthetic miRNA mimics and miRNA inhibitors, has shown promise in preclinical and clinical studies. These strategies aim to either enhance the activity of tumor-suppressive miRNAs or inhibit the function of oncogenic miRNAs, thereby restoring balanced signaling and impeding cancer progression. In conclusion, the crosstalk between miRNAs and signaling pathways in human cancers is a dynamic and influential aspect of cancer biology. Understanding this interplay provides valuable insights into cancer development and progression. Harnessing the therapeutic potential of miRNAs as regulators of signaling pathways opens up exciting opportunities for the development of innovative cancer treatments with the potential to improve patient outcomes. In this chapter, we provide an overview of the crosstalk between miRNAs and signaling pathways in the context of cancer and highlight the potential therapeutic implications of targeting this regulatory interplay.

Non-coding RNAs in Recurrent implantation failure

Recurrent implantation failure (RIF), defined as the inability to achieve conception following multiple consecutive in-vitro fertilization (IVF) attempts, represents a complex and multifaceted challenge in reproductive medicine. The emerging role of non-coding RNAs in RIF etiopathogenesis has only gained prominence over the last decade, illustrating a new dimension to our understanding of the intricate network underlying RIF. Successful embryo implantation demands a harmonious synchronization between an adequately decidualized endometrium, a competent blastocyst, and effective maternal-embryonic interactions. Emerging evidence has clarified the involvement of a sophisticated network of non-coding RNAs, including microRNAs, circular RNAs, and long non-coding RNAs, in orchestrating these pivotal processes. Disconcerted expression of these molecules can disrupt the delicate equilibrium required for implantation, amplifying the risk of RIF. This comprehensive review presents an in-depth investigation of the complex role played by non-coding RNAs in the pathogenesis of RIF. Furthermore, it underscores the vast potential of non-coding RNAs as diagnostic biomarkers and therapeutic targets, with the ultimate goal of enhancing implantation success rates in IVF cycles. As ongoing research continues to unravel the intercalated web of molecular interactions, exploiting the power of non-coding RNAs may offer promising avenues for mitigating the challenges posed by RIF and improving the outcomes of assisted reproduction.

Predictive, preventive, and personalized medicine in breast cancer: targeting the PI3K pathway

Breast cancer (BC) is a multifaceted disease characterized by distinct molecular subtypes and varying responses to treatment. In BC, the phosphatidylinositol 3-kinase (PI3K) pathway has emerged as a crucial contributor to the development, advancement, and resistance to treatment. This review article explores the implications of the PI3K pathway in predictive, preventive, and personalized medicine for BC. It emphasizes the identification of predictive biomarkers, such as PIK3CA mutations, and the utility of molecular profiling in guiding treatment decisions. The review also discusses the potential of targeting the PI3K pathway for preventive strategies and the customization of therapy based on tumor stage, molecular subtypes, and genetic alterations. Overcoming resistance to PI3K inhibitors and exploring combination therapies are addressed as important considerations. While this field holds promise in improving patient outcomes, further research and clinical trials are needed to validate these approaches and translate them into clinical practice.

MiR-188-5p regulates the proliferation and differentiation of goat skeletal muscle satellite cells by targeting calcium/calmodulin dependent protein kinase II beta

OBJECTIVE

The aim of this study was to reveal the role and regulatory mechanism of miR-188-5p in the proliferation and differentiation of goat muscle satellite cells.

METHODS

Goat skeletal muscle satellite cells isolated in the pre-laboratory were used as the test material. First, the expression of miR-188-5p in goat muscle tissues at different developmental stages was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, miR-188-5p was transfected into goat skeletal muscle satellite cells by constructing mimics and inhibitors of miR-188-5p, respectively. The changes of differentiation marker gene expression were detected by qPCR method.

RESULTS

It was highly expressed in adult goat latissimus dorsi and leg muscles, goat fetal skeletal muscle, and at the differentiation stage of muscle satellite cells. Overexpression and interference of miR-188-5p showed that miR-188-5p inhibited the proliferation and promoted the differentiation of goat muscle satellite cells. Target gene prediction and dual luciferase assays showed that miR-188-5p could target the 3'untranslated region of the calcium/calmodulin dependent protein kinase II beta (CAMK2B) gene and inhibit luciferase activity. Further functional studies revealed that CAMK2B promoted the proliferation and inhibited the differentiation of goat muscle satellite cells, whereas si-CAMK2B restored the function of miR-188-5p inhibitor.

CONCLUSION

These results suggest that miR-188-5p inhibits the proliferation and promotes the differentiation of goat muscle satellite cells by targeting CAMK2B. This study will provide a theoretical reference for future studies on the molecular mechanisms of skeletal muscle development in goats.

Integrative Approach to Identifying System-Level Mechanisms of Chung-Sang-Bo-Ha-Hwan's Influence on Respiratory Tract Diseases: A Network Pharmacological Analysis with Experimental Validation

Chung-Sang-Bo-Ha-Hwan (CSBHH) is an herbal prescription widely used to treat various chronic respiratory diseases. To investigate the system-level treatment mechanisms of CSBHH in respiratory tract diseases, we identified 56 active ingredients of CSBHH and evaluated the degree of overlap between their targets and respiratory tract disease-associated proteins. We then investigated the respiratory tract disease-related signaling pathways associated with CSBHH targets. Enrichment analysis showed that the CSBHH targets were significantly associated with various signaling pathways related to inflammation, alveolar structure, and tissue fibrosis. Experimental validation was conducted using phorbol-12-myristate-13-acetate (PMA)-stimulated NCI-H292 cells by analyzing the mRNA expression levels of biomarkers (IL-1β and TNF-α for inflammation; GSTP1, GSTM1, and PTEN for apoptosis) derived from network pharmacological analysis, in addition to the mucin genes MUC5AC and MUC2, to investigate the phlegm-expelling effect of CSBHH. The mRNA expression levels of these genes were consistent with network pharmacological predictions in a concentration-dependent manner. These results suggest that the therapeutic mechanisms of CSBHH in respiratory tract diseases could be attributed to the simultaneous action of multiple active ingredients in the herbal prescription.

Regulatory miRNAs, circRNAs and lncRNAs in cell cycle progression of breast cancer

Breast cancer is a complex and heterogeneous disease that poses a significant public health concern worldwide, and it remains a major challenge despite advances in treatment options. One of the main properties of cancer cells is the increased proliferative activity that has lost regulation. Dysregulation of various positive and negative modulators in the cell cycle has been identified as one of the driving factors of breast cancer. In recent years, non-coding RNAs have garnered much attention in the regulation of cell cycle progression, with microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs) being of particular interest. MiRNAs are a class of highly conserved and regulatory small non-coding RNAs that play a crucial role in the modulation of various cellular and biological processes, including cell cycle regulation. CircRNAs are a novel form of non-coding RNAs that are highly stable and capable of modulating gene expression at posttranscriptional and transcriptional levels. LncRNAs have also attracted considerable attention because of their prominent roles in tumor development, including cell cycle progression. Emerging evidence suggests that miRNAs, circRNAs and lncRNAs play important roles in the regulation of cell cycle progression in breast cancer. Herein, we summarized the latest related literatures in breast cancer that emphasize the regulatory roles of miRNAs, circRNAs and lncRNAs in cell cycle progress of breast cancer. Further understanding of the precise roles and mechanisms of non-coding RNAs in breast cancer cell cycle regulation could lead to the development of new diagnostic and therapeutic strategies for breast cancer.

MicroRNA-188-5p inhibits hepatocellular carcinoma proliferation and migration by targeting forkhead box N2

BACKGROUND

This study aimed to identify the biological functions, expression modes, and possible mechanisms underlying the relationship between metastatic human hepatocellular carcinoma (HCC) and MicroRNA-188-5p (miR-188) dysregulation using cell lines.

METHODS

A decrease in miR-188 was detected in low and high metastatic HCC cells compared to that in normal hepatic cells and non-invasive cell lines. Gain- and loss-of-function experiments were performed in vitro to investigate the role of miR-188 in cancer cell (Hep3B, HepG2, HLF, and LM3) proliferation and migration.

RESULTS

miR-188 mimic transfection inhibited the proliferation of metastatic HLF and LM3 cells but not non-invasive HepG2 and Hep3B cells; nonetheless, miR-188 suppression promoted the growth of HLF and LM3 cells. miR-188 upregulation inhibited the migratory rate and invasive capacity of HLF and LM3, rather than HepG2 and Hep3B cells, whereas transfection of a miR-188 inhibitor in HLF and LM3 cells had the opposite effects. Dual-luciferase reporter assays and bioinformatics prediction confirmed that miR-188 could directly target forkhead box N2 (FOXN2) in HLF and LM3 cells. Transfection of miR-188 mimics reduced FOXN2 levels, whereas miR-188 inhibition resulted in the opposite result, in HLF and LM3 cells. Overexpression of FOXN2 in HLF and LM3 cells abrogated miR-188 mimic-induced downregulation of proliferation, migration, and invasion. In addition, we found that miR-188 upregulation impaired tumor growth in vivo.

CONCLUSIONS

In summary, this study showed thatmiR-188 inhibits the proliferation and migration of metastatic HCC cells by targeting FOXN2.

Identification of Serum miR-501-3p and miR-338-3p as Novel Diagnostic Biomarkers for Breast Cancer and Their Target Genes Associated with Immune Infiltration

Background

MicroRNAs influence the growth and metastasis of breast cancer (BC) by regulating their target genes. Our study aims to screen and identify miRNAs that are closely related to the development of breast cancer, and explore the role of these miRNAs and their target genes in breast cancer.

Methods

Bioinformatics tools were applied to screen breast cancer-associated miRNAs and predict their potential target genes. Serum miRNAs were measured using RT-PCR. The correlation between miRNA expression and different clinicopathological features of BC patients was analyzed. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value. GEPIA, Kaplan-Meier Plotter, TIMER, and TISIDB databases were used to validate the expression levels and their prognostic value, as well as their target gene associated with immune infiltrating cells and immune checkpoints.

Results

Breast cancer-associated serum miR-338-3p and miR-501-3p were screened and verified for the first time. Serum miR-501-3p was elevated in BC and was closely linked to the ki-67 index and histological grade. CDKN2C, as a potential target gene of miR-501-3p, was enriched in the cGMP-PKG signaling pathway. Serum miR-338-3p was reduced in BC and was strongly linked to lymph node metastasis and histological grading. ACTR2, CDH1, COL1A1, RBBP5, RRM1, and TPM3, as potential target genes of miR-338-3p, were enriched in MAPK, PI3K-Akt, and RAS signaling pathways. These target genes were found to be linked to breast cancer prognosis, immune infiltrating cells, and immune checkpoint inhibitors. Analysis of ROC curve showed that serum miR-501-3p combined with serum miR-338-3p had a high diagnostic value in breast cancer (AUC: 0.89, 95% CI: 0.821-0.958).

Conclusion

Serum miR-501-3p combined with serum miR-338-3p show obvious clinical significance in the diagnosis and prognosis of breast cancer, which suggests that they may act as novel diagnostic biomarkers for breast cancer.

Key signal transduction pathways and crosstalk in cancer: Biological and therapeutic opportunities

Several different signaling pathways and molecular mechanisms have been identified as responsible for controlling critical functions in human cancer cells, such as selective growth and proliferative advantage, altered stress response favoring overall survival, vascularization, invasion and metastasis, metabolic rewiring, an abetting microenvironment, and immune modulation. This concise summary will provide a selective review of recent studies of key signal transduction pathways, including mitogen-activated protein kinase (MAPK) pathway, Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling, and Wnt/β-catenin signaling pathway, which are altered in cancer cells, as the novel and promising therapeutic targets.

MED16 Promotes Tumour Progression and Tamoxifen Sensitivity by Modulating Autophagy through the mTOR Signalling Pathway in ER-Positive Breast Cancer

Recent studies have shown that the mediator complex (MED) plays a vital role in tumorigenesis and development, but the role of MED16 (mediator complex subunit 16) in breast cancer (BC) is not clear. Increasing evidence has shown that the mTOR pathway is important for tumour progression and therapy. In this study, we demonstrated that the mTOR signalling pathway is regulated by the expression level of MED16 in ER+ breast cancer. With the analysis of bioinformatics data and clinical specimens, we revealed an elevated expression of MED16 in luminal subtype tumours. We found that MED16 knockdown significantly inhibited cell proliferation and promoted G1 phase cell cycle arrest in ER+ BC cell lines. Downregulation of MED16 markedly reduced the sensitivity of ER+ BC cells to tamoxifen and increased the stemness and autophagy of ER+ BC cells. Bioinformatic analysis of similar genes to MED16 were mainly enriched in autophagy, endocrine therapy and mTOR signalling pathways, and the inhibition of mTOR-mediated autophagy restored sensitivity to tamoxifen by MED16 downregulation in ER+ BC cells. These results suggest an important role of MED16 in the regulation of tamoxifen sensitivity in ER+ BC cells, crosstalk between the mTOR signalling pathway-induced autophagy, and together, with the exploration of tamoxifen resistance, may indicate a new therapy option for endocrine therapy-resistant patients.

Dysregulated MAPK signaling pathway in acute myeloid leukemia with RUNX1 mutations

BACKGROUND

: Acute myeloid leukemia (AML) is a hematologic malignancy with genetic alterations. RUNX1, which is an essential transcription factor for hematopoiesis, is frequently mutated in AML. Loss of function mutation of RUNX1 is correlated to poor prognosis of AML patients. It is urgent to reveal the underlying mechanism.

RESEARCH DESIGN AND METHODS

TCGA AML, GSE106291, GSE142700 and GSE67609 datasets were used. R package was used for define the differential expressed miRNAs, miRNA target genes, RUNX1 related gene, RUNX directly regulating genes, and so on. The relationship of gene expression with overall survival was analyzed by cox regression. KEGG and GO analysis were applied to the above mentioned genesets and overlapped genes. Alteration and importance of MAPK pathway was validated in K562 cells by Western blotting and apoptosis assay in vitro.

RESULTS

RUNX1 regulated MAPK pathway indirectly and directly. MAPK pathway was altered in K562 cells induced mutated RUNX1, and these cells were more sensitive to AraC after p38 was inhibited.

CONCLUSIONS

RUNX1 could modulate MAPK pathway, which may provide a potential therapeutic target for AML patients with RUNX1 mutations.

Circulating microRNA sequencing revealed miRNome patterns in hematology and oncology patients aiding the prognosis of invasive aspergillosis

Invasive aspergillosis (IA) may occur as a serious complication of hematological malignancy. Delays in antifungal therapy can lead to an invasive disease resulting in high mortality. Currently, there are no well-established blood circulating microRNA biomarkers or laboratory tests which can be used to diagnose IA. Therefore, we aimed to define dysregulated miRNAs in hematology and oncology (HO) patients to identify biomarkers predisposing disease. We performed an in-depth analysis of high-throughput small transcriptome sequencing data obtained from the whole blood samples of our study cohort of 50 participants including 26 high-risk HO patients and 24 controls. By integrating in silico bioinformatic analyses of small noncoding RNA data, 57 miRNAs exhibiting significant expression differences (P < 0.05) were identified between IA-infected patients and non-IA HO patients. Among these, we found 36 differentially expressed miRNAs (DEMs) irrespective of HO malignancy. Of the top ranked DEMs, we found 14 significantly deregulated miRNAs, whose expression levels were successfully quantified by qRT-PCR. MiRNA target prediction revealed the involvement of IA related miRNAs in the biological pathways of tumorigenesis, the cell cycle, the immune response, cell differentiation and apoptosis.

Apoptosis Induction, a Sharp Edge of Berberine to Exert Anti-Cancer Effects, Focus on Breast, Lung, and Liver Cancer

Cancer is the leading cause of death and one of the greatest barriers to increased life expectancy worldwide. Currently, chemotherapy with synthetic drugs remains one of the predominant ways for cancer treatment, which may lead to drug resistance and normal organ damage. Increasing researches have suggested that apoptosis, a type of programmed cell death, is a promising way for cancer therapy. Furthermore, natural products are important sources for finding new drugs with high availability, low cost and low toxicity. As a well-known isoquinoline alkaloid, accumulating evidence has revealed that berberine (BBR) exerts potential pro-apoptotic effects on multiple cancers, including breast, lung, liver, gastric, colorectal, pancreatic, and ovarian cancers. The related potential signal pathways are AMP-activated protein kinase, mitogen-activated protein kinase, and protein kinase B pathways. In this review, we provide a timely and comprehensive summary of the detailed molecular mechanisms of BBR in treating three types of cancer (breast, lung and liver cancer) by inducing apoptosis. Furthermore, we also discuss the existing challenges and strategies to improve BBR’s bioavailability. Hopefully, this review provides valuable information for the comprehension of BBR in treating three types of cancer and highlight the pro-apoptotic effects of BBR, which would be beneficial for the further development of this natural compound as an effective clinical drug for treating cancers.

Analysis and validation of m6A regulatory network: a novel circBACH2/has-miR-944/HNRNPC axis in breast cancer progression

Background

N6-methyladenosine (m6A), the most abundant and reversible modification of mRNAs in eukaryotes, plays pivotal role in breast cancer (BC) tumorigenesis and progression. Circular RNAs (circRNAs) can act as tumor promoters or suppressors by microRNA (miRNA) sponges in BC. However, the underlying mechanism of circRNAs in BC progression via regulating m6A modulators remains unclear.

Methods

Prognostic m6A RNA methylation regulators were identified in 1065 BC patients from The Cancer Genome Atlas (TCGA) project. Differentially expressed (DE) miRNAs and DE circRNAs were identified between BC and normal samples in TCGA and GSE101123, respectively. MiRNA-mRNA interactive pairs and circRNA-miRNA interactive pairs were verified by MiRDIP and Circular RNA Interactome. GSEA, KEGG, and ssGSEA were executed to explore the potential biological and immune functions between HNRNPC-high and HNRNPC-low expression groups. qRT-PCR and Western blot were used to quantify the expression of HNRNPC and circBACH2 in MCF-7 and MDA-MB-231 cells. The proliferation of BC cells was assessed by CCK-8 and EdU assay.

Results

2 m6A RNA methylation regulators with prognostic value, including HNRNPC and YTHDF3, were identified in BC patients. Then, the regulatory network of circRNA-miRNA-m6A modulators was constructed, which consisted of 2 DE m6A modulators (HNRNPC and YTHDF3), 12 DE miRNAs, and 11 DE circRNAs. Notably, BC patients with high expression of HNRNPC and low expression of hsa-miR-944 were correlated with late clinical stages and shorter survival times. Besides, the results from the KEGG inferred that the DE HNRNPC was associated with the MAPK signaling pathway in BC. Moreover, the circBACH2 (hsa_circ_0001625) was confirmed to act as hsa-miR-944 sponge to stimulate HNRNPC expression to promote BC cell proliferation via MAPK signaling pathway, thus constructing a circBACH2/hsa-miR-944/HNRNPC axis in BC.

Conclusions

Our findings decipher a novel circRNA-based m6A regulatory mechanism involved in BC progression, thus providing attractive diagnostic and therapeutic strategies for combating BC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03196-4.

MicroRNA‑200c‑3p suppresses intervertebral disc degeneration by targeting RAP2C/ERK signaling

Intervertebral disc degeneration (IDD) is a major cause of lower back pain. The high morbidity associated with this disease diminishes the quality of life of those who are affected. MicroRNAs (miRs) play crucial roles in various diseases, including IDD. However, the mechanism via which miR‑200c‑3p plays a role in the development of IDD remains unknown. The present study aimed to investigate the effect of miR‑200c‑3p on the progression of IDD and the underlying mechanism. The expression level of miR‑200c‑3p was evaluated in intervertebral disc tissues from patients with IDD. To construct the IDD cell model, the nucleus pulposus (NP) cells were treated with lipopolysaccharide (LPS) 24 h following transfection with miR‑200c‑3p mimic or inhibitor. A luciferase activity assay was performed, while reverse transcription‑quantitative PCR and western blotting were conducted to determine the RNA and protein expression levels, respectively. The expression level of miR‑200c‑3p in the intervertebral disc tissues of patients with IDD was lower than that of normal subjects. LPS treatment reduced the expression level of miR‑200c‑3p in NP cells. Moreover, miR‑200c‑3p mimic inhibited LPS‑induced NP cell apoptosis. It was found that miR‑200c‑3p attenuated inflammatory cytokine levels and extracellular matrix (ECM) degradation in NP cells. Furthermore, miR‑200c‑3p targeted Ras‑related protein 2C (RAP2C) in NP cells. RAP2C promoted apoptosis, inflammatory cytokine levels and ECM degradation by activating ERK signaling. Knockdown of RAP2C and inhibition of ERK signaling by SCH772984 partially reversed the proinflammatory effect of the miR‑200c‑3p inhibitor on LPS‑treated NP cells. Thus, miR‑200c‑3p inhibits NP cell apoptosis, inflammatory cytokine levels and ECM degradation in IDD by targeting RAP2C/ERK signaling.

Potentiated lung adenocarcinoma (LUAD) cell growth, migration and invasion by lncRNA DARS-AS1 via miR-188-5p/ KLF12 axis

Lung adenocarcinoma (LUAD) is the most common histological type of non-small cell lung cancer (NSCLC). Due to the nonspecific early symptoms, the majority of the diagnosed LUAD patients are in the middle and late stages, with multiple metastases, and have missed the optimal period for treatment. Current studies have reported lncRNA DARS-AS1 as a cancer-promoting gene that expedites tumorigenesis. This is the first study demonstrating that DARS-AS1 is involved in the mediating process of LUAD. Cell functional experiments revealed that lncRNA DARS-AS1 participated in enhancing LUAD proliferation, invasion, and migration by inhibiting miR-188-5p. The investigation on DARS-AS1/miR-188-5p led to the discovery of KLF12 as a downstream target of miR-188-5p, and the regulatory pathway was established as DARS-AS1/miR-188-5p/KLF12. According to western blot results, DARS-AS1 promoted LUAD cell growth, migration, and invasion via stimulation of the PI3K/AKT pathway, activating the EMT process, and up-regulating the CyclinD1 and Bcl-2 proteins. This was the first report on the DARS-AS1/miR-188-5p/KLF12 axis and offered a novel strategy for early diagnosis, a new therapeutic method, and an improved prognosis for LUAD.

CircRNAs: a family number of miRNA regulatory transcriptome in laryngeal carcinoma

Laryngeal carcinoma (LC) is a common head and neck cancer, which is the result of mutational changes due to gene dysregulation and etiological factors such as tobacco and smoking. A large number of patients received a poor prognosis due to diagnosis at an advanced stage. This highlights the need for definitive, early, and efficient diagnoses. With rapid development of high‐throughput sequencing, circular RNA (circRNA) has been reported to play a pivotal role in cancer. CircRNA functions as a microRNA (miRNA) sponge in the regulation of mRNA expression, forming circRNA‐miRNA regulatory axis. In this review, we described the axis in LC. The result indicated that CDR1as, hsa_circ_0042823, hsa_circ_0023028, circPARD3, hsa_circ_103862, hsa_circ_0000218, circMYLK, circCORO1C, hsa_circ_100290, circ‐CCND1, hsa_circ_0057481, circFLAN, and circRASSF2 expressed higher in LC, whereas, hsa_circ_0036722 and hsa_circ_0042666 expressed lower. The circRNAs regulated the target genes by sponging miRNAs and contributed to the pathogenesis of LC.

Association of miR-499 Polymorphism and Its Regulatory Networks with Hashimoto Thyroiditis Susceptibility: A Population-Based Case-Control Study

Hashimoto thyroiditis (HT) is a common autoimmune disorder with a strong genetic background. Several genetic factors have been suggested, yet numerous genetic contributors remain to be fully understood in HT pathogenesis. MicroRNAs (miRs) are gene expression regulators critically involved in biological processes, of which polymorphisms can alter their function, leading to pathologic conditions, including autoimmune diseases. We examined whether miR-499 rs3746444 polymorphism is associated with susceptibility to HT in an Iranian subpopulation. Furthermore, we investigated the potential interacting regulatory network of the miR-499. This case-control study included 150 HT patients and 152 healthy subjects. Genotyping of rs3746444 was performed by the PCR-RFLP method. Also, target genomic sites of the polymorphism were predicted using bioinformatics. Our results showed that miR-499 rs3746444 was positively associated with HT risk in heterozygous (OR = 3.32, 95%CI = 2.00–5.53, p < 0.001, CT vs. TT), homozygous (OR = 2.81, 95%CI = 1.30–6.10, p = 0.014, CC vs. TT), dominant (OR = 3.22, 95%CI = 1.97–5.25, p < 0.001, CT + CC vs. TT), overdominant (OR = 2.57, 95%CI = 1.62–4.09, p < 0.001, CC + TT vs. CT), and allelic (OR = 1.92, 95%CI = 1.37–2.69, p < 0.001, C vs. T) models. Mapping predicted target genes of miR-499 on tissue-specific-, co-expression-, and miR-TF networks indicated that main hub-driver nodes are implicated in regulating immune system functions, including immunorecognition and complement activity. We demonstrated that miR-499 rs3746444 is linked to HT susceptibility in our population. However, predicted regulatory networks revealed that this polymorphism is contributing to the regulation of immune system pathways.

Arf6 regulates energy metabolism in neutrophils

The small GTPase Arf6 regulates many cellular processes, including cytoskeletal remodeling, receptor endocytosis, and pathogen phagocytosis. Arf6 silencing in neutrophil (PMN)-like cells is well-known to inhibit chemotactic peptide-mediated activation of phospholipase D, the oxidative burst, and β2 integrin-dependent adhesion. In conditional knockout (cKO) mice, the migration to inflammatory sites of Arf6-deficient PMNs was diminished and associated with reduced cell surface expression of β2 integrins. In this study we assessed the impact of Arf6 depletion on the functions and gene expression profile of PMNs isolated from the mouse air pouch. Numerous genes involved in response to oxygen levels, erythrocyte and myeloid differentiation, macrophage chemotaxis, response to chemicals, apoptosis, RNA destabilization, endosome organization, and vesicle transport were differentially expressed in PMNs cKO for Arf6. Lpar6 and Lacc-1 were the most up-regulated and down-regulated genes, respectively. The deletion of Arf6 also decreased Lacc-1 protein level in PMNs, and silencing of Arf6 in THP-1 monocytic cells delayed LPS-mediated Lacc-1 expression. We report that fMLP or zymosan-induced glycolysis and oxygen consumption rate were both decreased in air pouch PMNs but not in bone marrow PMNs of Arf6 cKO mice. Reduced oxygen consumption correlated with a decrease in superoxide and ROS production. Deletion of Arf6 in PMNs also reduced phagocytosis and interfered with apoptosis. The data suggest that Arf6 regulates energy metabolism, which may contribute to impaired phagocytosis, ROS production, and apoptosis in PMN-Arf6 cKO. This study provides new information on the functions and the inflammatory pathways influenced by Arf6 in PMNs.

Long non-coding RNA RP11-283G6.5 confines breast cancer development through modulating miR-188-3p/TMED3/Wnt/β-catenin signalling

The contributions of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) to breast cancer are critical areas of investigation. In this study, we identified a novel lncRNA RP11-283G6.5 which was lowly expressed in breast cancer and whose low expression was correlated with poor overall survival and disease-free survival of breast cancer patients. Functional experiments revealed that ectopic expression of RP11-283G6.5 confined breast cancer cellular growth, migration, and invasion, and promoted cellular apoptosis. Conversely, RP11-283G6.5 silencing facilitated breast cancer cellular growth, migration, and invasion, and repressed cellular apoptosis. Moreover, RP11-283G6.5 was found to confine breast cancer tumour growth and metastasis in vivo. Mechanistically, RP11-283G6.5 competitively bound to ILF3, reduced the binding of ILF3to primary miR-188 (pri-miR-188), abolished the suppressive effect of ILF3 on pri-miR-188 processing, and therefore promoted pri-miR-188 processing, leading to the reduction of pri-miR-188 and the upregulation of mature miR-188-3p. The expression of RP11-283G6.5 was significantly positively correlated with that of miR-188-3p in breast cancer tissues. Through increasing miR-188-3p, RP11-283G6.5 decreased TMED3, a target of miR-188-3p. RP11-283G6.5 further suppressed Wnt/β-catenin signalling via decreasing TMED3. Rescue assays revealed that inhibition of miR-188-3p, overexpression of TMED3 or blocking Wnt/β-catenin signalling all attenuated the roles of RP11-283G6.5 in breast cancer. Collectively, these findings demonstrated that RP11-283G6.5 is a tumour suppressive lncRNA in breast cancer via modulating miR-188-3p/TMED3/Wnt/β-catenin signalling. This study indicated that RP11-283G6.5 might be a promising prognostic biomarker and therapeutic target for breast cancer.

GLUT3 as an Intersection of Glycerophospholipid Metabolism and the Innate Immune Response to Candida albicans

Immune cells can optimize the management of metabolic resources to balance their energy requirements in order to regulate immune responses. The interconnection between immunometabolism and fungal infections is becoming increasingly apparent. Using proteome and metabolome assays, we found that stimulation of primary human monocytes by Candida albicans was accompanied by upregulation of glucose transporter 3 (GLUT3) and activation of the glycerophospholipid metabolism pathway. Upregulated GLUT3 expression has been preliminarily confirmed in monocytes from patients with C. albicans bloodstream infection. Our findings support the importance of GLUT3 in the complex network of glycerophospholipid metabolism and the innate immune responses against C. albicans. In summary, this study might contribute to decipher the regulatory mechanism between the monocyte metabolic reprogramming and innate immune response and reveal potential targets for the antifungal treatments.

Serum long non‑coding RNA NNT‑AS1 protected by exosome is a potential biomarker and functions as an oncogene via the miR‑496/RAP2C axis in colorectal cancer

Increasing evidence has indicated that long non-coding RNAs (lncRNAs) serve an essential role in carcinogenesis and cancer development. It has been reported that lncRNA nicotinamide nucleotide transhydrogenase antisense RNA 1 (NNT-AS1) serves a crucial role in several types of cancer. However, the clinical significance of circulating NNT-AS1 expression in colorectal cancer (CRC) remains to be elucidated. The current study aimed to investigate the potential role of NNT-AS1 and the clinical significance of its serum expression levels in patients with CRC. The expression of NNT-AS1 was measured in 40 pairs of tumor and adjacent normal tissues from patients with CRC via reverse transcription-quantitative PCR. The serum expression levels of NNT-AS1 were assayed in an independent cohort of healthy controls and patients with CRC. The levels of NNT-AS1 were also compared between paired preoperative and postoperative serum samples. In addition, the presence of exosomal NNT-AS1 in serum was explored. Furthermore, the biological roles of NNT-AS1 were investigated in CRC cells in vitro. The expression of NNT-AS1 was significantly upregulated in tumor tissues compared with adjacent normal tissues (P<0.05). A higher level of NNT-AS1 was associated with an advanced CRC stage. The serum levels of NNT-AS1 were significantly upregulated in patients with CRC compared with healthy subjects (P<0.05). Furthermore, the NNT-AS1 levels were significantly decreased in postoperative samples compared with preoperative samples (P<0.01). In addition, it was also identified that NNT-AS1 was upregulated in CRC exosomes (P<0.01), whereas no significant difference was observed in NNT-AS1 levels between serum and exosomes. Silencing of NNT-AS1 inhibited the proliferation, migration and invasion of CRC cells. It was also identified that NNT-AS1 exerted its effects via regulation of the microRNA-496/Ras-related protein Rap-2c axis. The present study demonstrated that circulating NNT-AS1, which may be protected by exosomes, could be a novel potential biomarker and therapeutic target in CRC.

Critical signaling pathways governing hepatocellular carcinoma behavior; small molecule-based approaches

Hepatocellular carcinoma (HCC) is the second leading cause of death due to cancer. Although there are different treatment options, these strategies are not efficient in terms of restricting the tumor cell's proliferation and metastasis. The liver tumor microenvironment contains the non-parenchymal cells with supportive or inhibitory effects on the cancerous phenotype of HCC. Several signaling pathways are dis-regulated in HCC and cause uncontrolled cell propagation, metastasis, and recurrence of liver carcinoma cells. Recent studies have established new approaches for the prevention and treatment of HCC using small molecules. Small molecules are compounds with a low molecular weight that usually inhibit the specific targets in signal transduction pathways. These components can induce cell cycle arrest, apoptosis, block metastasis, and tumor growth. Devising strategies for simultaneously targeting HCC and the non-parenchymal population of the tumor could lead to more relevant research outcomes. These strategies may open new avenues for the treatment of HCC with minimal cytotoxic effects on healthy cells. This study provides the latest findings on critical signaling pathways governing HCC behavior and using small molecules in the control of HCC both in vitro and in vivo models.

Construction of Circular RNA-MicroRNA-Messenger RNA Regulatory Network of Recurrent Implantation Failure to Explore Its Potential Pathogenesis

Background: Many studies on circular RNAs (circRNAs) have recently been published. However, the function of circRNAs in recurrent implantation failure (RIF) is unknown and remains to be explored. This study aims to determine the regulatory mechanisms of circRNAs in RIF.

Methods: Microarray data of RIF circRNA (GSE147442), microRNA (miRNA; GSE71332), and messenger RNA (mRNA; GSE103465) were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed circRNA, miRNA, and mRNA. The circRNA–miRNA–mRNA network was constructed by Cytoscape 3.8.0 software, then the protein–protein interaction (PPI) network was constructed by STRING database, and the hub genes were identified by cytoHubba plug-in. The circRNA–miRNA–hub gene regulatory subnetwork was formed to understand the regulatory axis of hub genes in RIF. Finally, the Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the hub genes were performed by clusterProfiler package of Rstudio software, and Reactome Functional Interaction (FI) plug-in was used for reactome analysis to comprehensively analyze the mechanism of hub genes in RIF.

Results: A total of eight upregulated differentially expressed circRNAs (DECs), five downregulated DECs, 56 downregulated differentially expressed miRNAs (DEmiRs), 104 upregulated DEmiRs, 429 upregulated differentially expressed genes (DEGs), and 1,067 downregulated DEGs were identified regarding RIF. The miRNA response elements of 13 DECs were then predicted. Seven overlapping miRNAs were obtained by intersecting the predicted miRNA and DEmiRs. Then, 56 overlapping mRNAs were obtained by intersecting the predicted target mRNAs of seven miRNAs with 1,496 DEGs. The circRNA–miRNA–mRNA network and PPI network were constructed through six circRNAs, seven miRNAs, and 56 mRNAs; and four hub genes (YWHAZ, JAK2, MYH9, and RAP2C) were identified. The circRNA–miRNA–hub gene regulatory subnetwork with nine regulatory axes was formed in RIF. Functional enrichment analysis and reactome analysis showed that these four hub genes were closely related to the biological functions and pathways of RIF.

Conclusion: The results of this study provide further understanding of the potential pathogenesis from the perspective of circRNA-related competitive endogenous RNA network in RIF.

Honokiol antagonizes doxorubicin resistance in human breast cancer via miR-188-5p/FBXW7/c-Myc pathway

BACKGROUND

Honokiol, a natural phenolic compound derived from Magnolia plants, is a promising anti-tumor compound that exerts a wide range of anti-cancer effects. Herein, we investigated the effect of honokiol on doxorubicin resistance in breast cancer.

METHODS

Doxorubicin-sensitive (MCF-7 and MDA-MB-231) and doxorubicin-resistant (MCF-7/ADR and MDA-MB-231/ADR) breast cancer cell lines were treated with doxorubicin in the absence or presence of honokiol; then, the following tests were performed: flow cytometry for cell apoptosis, WST-1 assay for cell viability, qPCR and western blot for the expression of miR-188-5p, FBXW7, and c-Myc. MiR-188-5p mimic, miR-188-5p inhibitor, siFBXW7, and c-Myc plasmids were transfected into cancer cells to evaluate whether miR-188-5p and FBXW7/c-Myc signaling are involved in the effect of honokiol on doxorubicin resistance in breast cancer. A dual luciferase reporter system was used to study the direct interaction between miR-188-5p and FBXW7.

RESULTS

Honokiol sensitized doxorubicin-resistant breast cancer cells to doxorubicin-induced apoptosis. Mechanically, upregulation of miR-188-5p was associated with doxorubicin resistance, and honokiol enhanced doxorubicin sensitivity by downregulating miR-188-5p. FBXW7 was confirmed to be a direct target gene of miR-188-5p. FBXW7/c-Myc signaling was involved in the chemosensitization effect of honokiol. Honokiol induced apoptosis in MCF-7/ADR and MDA-MB-231/ADR cells. However, FBXW7 silencing or c-Myc transfection resulted in resistance to the honokiol-induced apoptotic effect.

CONCLUSION

These findings suggest that downregulation of miR-188-5p by honokiol enhances doxorubicin sensitivity through FBXW7/c-Myc signaling in human breast cancer. Our study finds an important role of miR-188-5p in the development of doxorubicin resistance in breast cancer, and enriches our understanding of the mechanism of action of honokiol in cancer therapy.

RNA-binding protein QKI suppresses breast cancer via RASA1/MAPK signaling pathway

Background

RNA-binding protein Quaking (QKI) has been linked with the pathogenesis and development of various human malignancies. Herein, we explored the particular role of QKI in breast cancer (BC) progression.

Methods

The methods employed in the study included public dataset analysis, western blot, quantitative real-time PCR (qRT-PCR), cell count kit-8 (CCK8) assay, colony formation assay, flow cytometric analysis, RNA immunoprecipitation (RIP), messenger RNA (mRNA) stability assay, QKI overexpression and knockdown, and Ras p21 protein activator 1 (RASA1) knockdown.

Results

Aberrant expression levels of QKI and RASA1 were detected in BC and compared with those in noncancerous tissues. A moderately positive correlation between QKI and RASA1 was verified within BC tissues. Low expression of QKI was associated with positive estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status, non-triple-negative breast cancer (TNBC), non-basal-like BC, and poor clinical outcomes in BC patients. QKI overexpression suppressed BC cell proliferation and colony formation, and arrested cell cycle at G1 phase. RIP assay and mRNA stability assay confirmed that QKI directly bound to RASA1 transcript and increased its stability, thus inactivating the MAPK pathway and inhibiting BC progression. RASA1 knockdown could partly attenuate the inhibitory effect of QKI on BC cell proliferation via activating the mitogen-activated protein kinase (MAPK) pathway.

Conclusions

QKI, which was frequently downregulated in BC, could significantly inhibit cell proliferation and arrest cell cycle at G1 phase by binding and enhancing RASA1 mRNA expression. Low expression of QKI was prominently associated with unfavorable clinical outcomes in BC patients, indicating the prognostic value of QKI in BC.

Thioridazine hydrochloride: an antipsychotic agent that inhibits tumor growth and lung metastasis in triple-negative breast cancer via inducing G0/G1 arrest and apoptosis

ABBREVIATIONS

CCK8: Cell Counting Kit-8; CDK: cyclin-dependent kinase; DRD2: dopamine D2 receptor; ERK1/2: extracellular signal-regulated kinase 1/2; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; H&E: hematoxylin and eosin; MMP: membrane potential; NAC: N-acetyl-L-cysteine; PI: Propidium iodide; Rh123: rhodamine-123; ROS: reactive oxygen species; TBST: tris-buffered saline containing 0.1% Tween 20 TNBC: Triple-negative breast cancer; Thi-hyd: Thioridazine hydrochloride.

microRNA-195 Promotes Small Cell Lung Cancer Cell Apoptosis via Inhibiting Rap2C Protein-Dependent MAPK Signal Transduction

This study aimed to explore the influences of microRNA-195 (miRNA-195)/Rap2C/MAPK in the proliferation and apoptosis of small cell lung cancer (SCLC) cells. QRT-PCR analysis were executed to evaluate miRNA-195 expression in lung cancer tissues and SCLC cells, and the western blot was implemented to monitor Rap2C protein level and uncovered whether the MAPK signaling pathway in lung cancer tissues and SCLC cells was activated. The CCK-8 experiment was performed to detect cell proliferation ability, and the flow cytometry was utilized to examine cell apoptosis level. Luciferase reporter gene system was executed to disclose the interaction between miRNA-195 and Rap2C. Subcutaneous implantation mouse models of SCLC cells were constructed to detect cell proliferation in vivo, and Kaplan-Meier method calculated patient survival. The expression of Rap2C was higher in lung cancer tissues and SCLC cells than in normal tissues and cells, while the expression of miRNA-195 was lower in lung cancer tissues and SCLC cells than in normal tissues and cells. miRNA-195 lower expression predicted showed reduced overall survival in lung cancer patients. Further loss of function and enhancement experiments revealed that miRNA-195 overexpression could significantly inhibit SCLC cell proliferation and promote cell apoptosis by upregulation of Bax and down-regulation of bcl-2; Luciferase reporter assay demonstrated that miRNA-195 could bind to Rap2C mRNA and inhibit its expression, Rap2C overexpression also related to the poorer prognosis of lung patients. Knockdown of Rap2C suppressed cell proliferation and expedited apoptosis. In addition, overexpression of Rap2C reversed miRNA-195-induced apoptosis and proliferation inhibition. Furthermore, miRNA195 prohibited the activation of MAPK signaling pathway by down-regulating Rap2C. These consequences indicated that miRNA-195 promotes the apoptosis and inhibits the proliferation of small cell lung cancer (SCLC) cells via inhibiting Rap2C protein-dependent MAPK signal transduction

Berberine Inhibits the Expression of SCT through miR-214-3p Stimulation in Breast Cancer Cells

In this study, we aimed to evaluate the suppressive abilities of berberine (BBR) on MCF-7 and MDA-MB-231 cells and confirm its underlying mechanisms on miR-214-3p. We first built a panel of 18 miRNAs and 9 lncRNAs that were reported to participate in the mechanism of breast cancer. The RT-qPCR results suggested that BBR illustrated a dosage-dependent pattern in the stimulation to miR-214-3p in both MCF-7 and MDA-MB-231 cells. Then, we performed gain-and-lose function tests to validate the role of miR-214-3p contributing to the anticancer effects of BBR. Both BBR and miR-214-3p mimic reduced the cell viability, repressed migration and invasion capacities, increased rates of total apoptotic cells and ratio of Bax/Bcl-2, and increased the percentage of G2/M cells of MCF-7 and MDA-MB-231 cells by colony formation and CKK8 assay, scratch wound healing and gelatin-based 3D conformation assay, transwell invasion assay, and cell cycle analysis, respectively. However, miR-214-3p inhibitor counteracted all these effects of BBR. Based on the bioinformatics analysis and dual-luciferase reporter test, we identified binding sites between SCT and miR-214-3p. We further confirmed that BBR massively and dose-dependently reduced the mRNA expression and protein levels of SCT in both MCF-7 and MDA-231 cells. We testified that both miR-214-3p mimic and BBR could decrease the mRNA expression and protein levels of SCT, while miR-214-3p inhibitor weakened these reductions. In conclusion, BBR suppressed MCF-7 and MDA-MB-231 breast cancer cells by upregulating miR-214-3p and increasing its inhibition to SCT.

Circulating MicroRNAs as Prognostic and Therapeutic Biomarkers in Breast Cancer Molecular Subtypes

Breast cancer (BC) is a common and heterogeneous disease, of which six molecular subtypes, characterized by different biological features and clinical outcomes, were described. The identification of additional biomarkers able to further connote and distinguish the different BC subtypes is essential to improve the diagnostic, prognostic and therapeutic strategies in BC patients. MicroRNAs (miRNAs) are short non-coding RNA involved in several physiological and pathological processes, including cancer development and progression. In particular, circulating miRNAs, which can be found in an adequately stable structure in serum/plasma of cancer patients, are emerging as very promising non-invasive biomarkers. Several studies have analyzed the potential role of circulating miRNAs as prognostic and therapeutic markers in BC. In the present review we describe circulating miRNAs, identified as putative biomarker in BC, with special reference to different BC molecular subtypes.

Circular RNA ZNF609 Promoted Hepatocellular Carcinoma Progression by Upregulating PAP2C Expression via Sponging miR-342-3p

Background

Emerging evidence has revealed that circular RNAs (circRNAs) participated in hepatocellular carcinoma (HCC) development. However, the roles of most circRNAs have not been studied.

Methods

CircZNF609, miR-342-3p and RAP2C expressions were assessed by qPCR or Western blot. Loss-of-function experiments were performed using si-circZNF609 transfection, followed by CCK-8 assay, flow cytometry, wound healing assay and transwell assay. Informatic tools and rescue experiments were carried out to investigate the underlying mechanisms.

Results

We showed that circZNF609 was overexpressed in HCC tissues and cells, as well as associated with poor clinical characteristics. Depletion of circZNF609 restrained HCC cell viability, migration and invasion while enhanced cell apoptosis. As to mechanism, miR-342-3p was sponged by circZNF609, and RAP2C was targeted by miR-342-3p. The effects on HCC cells induced by si-circZNF609 could be reversed by miR-342-3p inhibitor or RAP2C. In vivo, circZNF609 knockdown inhibited tumorigenesis of HCC mice, confirming the findings in vitro.

Conclusion

CircZNF609 was highly expressed in HCC tissues and driven HCC progression by sponging miR-342-3p and upregulating RAP2C. This study may provide new potential therapeutic targets for HCC treatment.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

Rap2c as a Novel Biomarker for Predicting Poor Prognosis in Glioma

Objective

Rap2c is a member of the Ras superfamily that has been implicated in various types of cancers. However, its role in glioma remains elusive. This study aimed to elucidate the role of Rap2c in glioma and its specific molecular mechanism.

Methods

We determined the expression of Rap2c in glioma tissues by Western blotting and immunohistochemistry (IHC) assays. The proliferation and apoptosis of cells were explored using CCK-8 and flow cytometry assay, whereas the migration and invasion of glioma cells were determined using transwell assay. The potential mechanism of Rap2c in the migration of glioma cell lines was investigated through Western blotting analysis and transwell assay. BALB/c nude mice were used to establish tumor models to test the effect of Rap2c on cancer metastasis in vivo.

Results

Our data showed that the protein expression of Rap2c was significantly up-regulated in glioma tissues compared with normal brain tissues, and Rap2c overexpression negatively correlated with 5-year overall survival rate. However, there was no correlation between Rap2c expression and clinicopathological parameters of glioma patients. Overexpression of Rap2c promoted the migration and invasion abilities of glioma cells but had no significant effect on the proliferation of glioma cells. Western blotting analysis revealed that Rap2c overexpression increased the phosphorylation level of extracellular signal-related kinase1/2 (ERK1/2), and this effect was abolished with U0126, a selective MEK inhibitor. Furthermore, overexpression of Rap2c induced lung metastasis of glioma cells in xenograft models.

Conclusion

These findings indicate that high Rap2c expression predicts poor prognosis in glioma. Rap2c-mediated ERK1/2 phosphorylation initiates EMT cascade and promotes migration and invasion of glioma cells. Thus, targeting Rap2c and ERK signaling pathway could be a novel treatment modality for glioma.

Overexpression of circRNA_100290 promotes the progression of laryngeal squamous cell carcinoma through the miR-136-5p/RAP2C axis

Circular RNAs (circRNAs) exert critical functions in tumorigenesis and tumor development, but whether and how circRNAs contribute to laryngeal squamous cell carcinoma (LSCC) is unclear. In this study, we explored the function and mechanisms of circRNA_100290 in LSCC. Tissue samples were obtained from 40 patients with LSCC. The expression of circRNA_100290 and other targets was measured through quantitative reverse transcription-polymerase chain reaction and western blot analysis. Cell proliferation, colony-forming ability, and apoptosis were tested using CCK-8 assay and EdU assay, colony formation assay, and flow cytometry, respectively. Cell migration and invasion were detected by Transwell assay. Moreover, the interactions between circRNA_100290, miR-136-5p, and RAP2C were analyzed by bioinformatics, and verified by dual-luciferase reporter assays. Here, we found that circRNA_100290 expression was significantly upregulated in LSCC tissues and cell lines compared with the normal controls. Expression of circRNA_100290 positively correlated with advanced TNM stage and lymph node metastasis in LSCC patients. In cell culture, upregulation of circRNA_100290 promoted LSCC cell proliferation, migration, and invasion, while it inhibited cell apoptosis; downregulating circRNA_100290 exerted the opposite effects. In vivo, circRNA_100290 overexpression dramatically promoted tumor growth. Mechanistically, circRNA_100290 may act as a sponge of miR-136-5p, and inhibiting miR-136-5p in LSCC cells indeed reversed the effects of circRNA_100290 downregulation. The RAS oncogene RAP2C was predicted to be a target of miR-136-5p, and downregulating RAP2C in LSCC cells partially reversed the oncogenic effects of circRNA_100290 overexpression or miR-136-5p decrease. Our findings suggest that circRNA_100290 promotes LSCC progression by targeting the miR-136-5p/RAP2C axis, which may lead to the identification of potential therapeutic targets.