LncRNA SNHG4 regulates miR-10a/PTEN to inhibit the proliferation of acute myeloid leukemia cells

SNHG4-mediated PTEN destabilization confers oxaliplatin resistance in colorectal cancer cells by inhibiting ferroptosis

Oxaliplatin resistance poses a significant challenge in colorectal cancer (CRC) therapy, necessitating further investigation into the underlying molecular mechanisms. This study aimed to elucidate the regulatory role of SNHG4 in oxaliplatin resistance and ferroptosis in CRC. Our findings revealed that treatment with oxaliplatin led to downregulation of SNHG4 expression in CRC cells, while resistant CRC cells exhibited higher levels of SNHG4 compared to parental cells. Silencing SNHG4 attenuated oxaliplatin resistance and reduced the expression of resistance-related proteins MRD1 and MPR1. Furthermore, induction of ferroptosis effectively diminished oxaliplatin resistance in both parental and resistant CRC cells. Notably, ferroptosis induction resulted in decreased SNHG4 expression, whereas SNHG4 overexpression suppressed ferroptosis. Through FISH, RIP, and RNA pull-down assays, we identified the cytoplasmic localization of both SNHG4 and PTEN, establishing that SNHG4 directly targets PTEN, thereby reducing mRNA stability in CRC cells. Silencing PTEN abrogated the impact of SNHG4 on oxaliplatin resistance and ferroptosis in CRC cells. In vivo experiments further validated the influence of SNHG4 on oxaliplatin resistance and ferroptosis in CRC cells through PTEN regulation. In conclusion, SNHG4 promotes resistance to oxaliplatin in CRC cells by suppressing ferroptosis through instability of PTEN, thus serves as a target for patients with oxaliplatin-base chemoresistance.

Long non-coding RNA SNHG4 aggravates cigarette smoke-induced COPD by regulating miR-144-3p/EZH2 axis

OBJECTIVE

The purpose of this study was to explore the expression level of SNHG4 in patients with COPD and its diagnostic value in COPD, to probe the biological function of SNHG4 in COPD at the cellular level, and to reveal the interaction between SNHG4 and miR-144-3p/EZH2 axis.

METHODS

The serum levels of SNHG4, miR-144-3p and EZH2 in healthy people and patients with COPD were detected by RT-qPCR. The diagnostic value of SNHG4 in COPD was evaluated by ROC curve. Pearson method was chosen to estimate the correlation between SNHG4 and clinical indicators in patients with COPD. Cigarette smoke extract (CSE) was obtained, and Beas-2B cells were exposed with 2% CSE to establish an inflammatory cell model of COPD in vitro. MTT assay was used to detect cell viability, flow cytometry was used to evaluate cell apoptosis, and ELISA was performed to detect inflammatory cytokines. Dual-luciferase reporting assay was carried out to verify the targeting of lncRNA-miRNA or miRNA-mRNA.

RESULTS

(1) The expression of SNHG4 is decreased in patients with COPD, and the expression level in acute exacerbation COPD was lower than that in stable COPD. SNHG4 demonstrated high diagnostic accuracy in distinguishing between stable and acute exacerbation COPD. (2) The expression of SNHG4 was decreased in CSE-induced Beas-2B cells, and overexpression of SNHG4 was beneficial to alleviate CSE-induced apoptosis and inflammation. (3) The expression of miR-144-3p is up-regulated in patients with COPD and CSE-induced Beas-2B cells. MiR-144-3p has a targeting relationship with SNHG4, which is negatively regulated by SNHG4. Overexpression of miR-144-3p could counteract the beneficial effects of increased SNHG4 on CSE-induced cells. (4) The expression of EZH2 is reduced in patients with COPD and CSE-induced Beas-2B cells. Bioinformatics analysis and luciferase reporter gene confirmed that EZH2 is the downstream target gene of miR-144-3p and is negatively regulated by miR-144-3p.

CONCLUSION

The expression of SNHG4 decreased in patients with COPD, and it may promote the progression of COPD by inhibiting the viability, promoting apoptosis and inflammatory response of bronchial epithelial cells via regulating the miR-144-3p/EZH2 axis.

The siRNA-mediated knockdown of SNHG4 efficiently induced pro-apoptotic signaling and suppressed metastasis in SW1116 colorectal cancer cell line

BACKGROUND

Long non-coding RNAs are broadly dysregulated in disease conditions, especially cancer, and are associated with tumor initiation, invasion, and overall survival. This study aimed to elucidate the expression level of Small Nucleolar RNA Host Gene 4 (SNHG4) lncRNA in colorectal cancer (CRC) and its effect on cell cycle progression, invasion, and death.

METHODS AND RESULTS

We evaluated the expression level of SNHG4 in clinical samples, including CRC tissues, adenomatous colorectal polyps (ACP), and their marginals. SNHG4-silenced SW1116 cells were used to evaluate the cell viability, cycle arrest, invasion, and apoptosis using MTT assay, scratching, flow cytometry, and immunoblotting. We also predicted molecular networks related to the SNHG4 involvement in CRC development. Results showed that SNHG4 expresses in cancerous tissues significantly higher than in polyps and marginals. This overexpression discriminated CRC from marginals and ACP with a suitable prognostic potential. Silencing of SNHG4 arrested the cell cycle at S and G2 phases and promoted early apoptosis in SW1116. It affected the active form of MMP2 and prevented cell invasion. Sponging of miRNAs which promotes the choline metabolism is the probable mechanism of SNHG4 involvement in CRC.

CONCLUSIONS

In conclusion, SNHG4 promotes CRC by dysregulating apoptosis and cell migration, and shows significant prognostic potential for CRC.

Transcriptomic analyses of ovarian clear-cell carcinoma with concurrent endometriosis

Introduction

Endometriosis, a benign inflammatory disease whereby endometrial-like tissue grows outside the uterus, is a risk factor for endometriosis-associated ovarian cancers. In particular, ovarian endometriomas, cystic lesions of deeply invasive endometriosis, are considered the precursor lesion for ovarian clear-cell carcinoma (OCCC).

Methods

To explore this transcriptomic landscape, OCCC from women with pathology-proven concurrent endometriosis (n = 4) were compared to benign endometriomas (n = 4) by bulk RNA and small-RNA sequencing.

Results

Analysis of protein-coding genes identified 2449 upregulated and 3131 downregulated protein-coding genes (DESeq2, P< 0.05, log2 fold-change > |1|) in OCCC with concurrent endometriosis compared to endometriomas. Gene set enrichment analysis showed upregulation of pathways involved in cell cycle regulation and DNA replication and downregulation of pathways involved in cytokine receptor signaling and matrisome. Comparison of pathway activation scores between the clinical samples and publicly-available datasets for OCCC cell lines revealed significant molecular similarities between OCCC with concurrent endometriosis and OVTOKO, OVISE, RMG1, OVMANA, TOV21G, IGROV1, and JHOC5 cell lines. Analysis of miRNAs revealed 64 upregulated and 61 downregulated mature miRNA molecules (DESeq2, P< 0.05, log2 fold-change > |1|). MiR-10a-5p represented over 21% of the miRNA molecules in OCCC with endometriosis and was significantly upregulated (NGS: log2fold change = 4.37, P = 2.43e-18; QPCR: 8.1-fold change, P< 0.05). Correlation between miR-10a expression level in OCCC cell lines and IC50 (50% inhibitory concentration) of carboplatin in vitro revealed a positive correlation (R2 = 0.93). MiR-10a overexpression in vitro resulted in a significant decrease in proliferation (n = 6; P< 0.05) compared to transfection with a non-targeting control miRNA. Similarly, the cell-cycle analysis revealed a significant shift in cells from S and G2 to G1 (n = 6; P< 0.0001). Bioinformatic analysis predicted that miR-10a-5p target genes that were downregulated in OCCC with endometriosis were involved in receptor signaling pathways, proliferation, and cell cycle progression. MiR-10a overexpression in vitro was correlated with decreased expression of predicted miR-10a target genes critical for proliferation, cell-cycle regulation, and cell survival including [SERPINE1 (3-fold downregulated; P< 0.05), CDK6 (2.4-fold downregulated; P< 0.05), and RAP2A (2-3-fold downregulated; P< 0.05)].

Discussion

These studies in OCCC suggest that miR-10a-5p is an impactful, potentially oncogenic molecule, which warrants further studies.

The non-coding competing endogenous RNAs in acute myeloid leukemia: biological and clinical implications

Acute myeloid leukemia (AML) is a hematologic carcinoma that has seen a considerable improvement in patient prognosis because of genetic diagnostics and molecularly-targeted therapies. Nevertheless, recurrence and drug resistance remain significant obstacles to leukemia treatment. It is critical to investigate the underlying molecular mechanisms and find solutions. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), circular RNAs, long non-coding RNAs, and pseudogenes, have been found to be crucial components in driving cancer. The competing endogenous RNA (ceRNA) mechanism has expanded the complexity of miRNA-mediated gene regulation. A great deal of literature has shown that ncRNAs are essential to the biological functions of the ceRNA network (ceRNET). NcRNAs can compete for the same miRNA response elements to influence miRNA-target RNA interactions. Recent evidence suggests that ceRNA might be a potential biomarker and therapeutic strategy. So far, however, there have been no comprehensive studies on ceRNET about AML. What is not yet clear is the clinical application of ceRNA in AML. This study attempts to summarize the development of research on the related ceRNAs in AML and the roles of ncRNAs in ceRNET. We also briefly describe the mechanisms of ceRNA and ceRNET. What's more significant is that we explore the clinical value of ceRNAs to provide accurate diagnostic and prognostic biomarkers as well as therapeutic targets. Finally, limitations and prospects are considered.

LncRNA SNHG4 Modulates EMT Signal and Antitumor Effects in Endometrial Cancer through Transcription Factor SP-1

Long non-coding RNAs (lncRNAs) are implicated in the initiation and progression of a variety of tumors, including endometrial cancer. However, the mechanisms of lncRNA in endometrial cancer formation and progression remain largely unknown. In this study, we confirmed that the lncRNA SNHG4 is upregulated in endometrial cancer and correlates with lower survival rates in endometrial cancer patients. Knock-down of SNHG4 significantly reduced cell proliferation, colonization, migration, and invasion in vitro, as well as modulating the cell cycle and reduced tumor growth of endometrial cancer in vivo. In addition, the effect of SNHG4 by the transcription factor SP-1 was confirmed in vitro. We found in this study that SNHG4/SP-1 plays an important role in endometrial cancer progression and may be used as a potential therapeutic and prognostic biomarker for endometrial cancer.

Advances in targeting of miR‑10‑associated lncRNAs/circRNAs for the management of cancer (Review)

With advancements in sequencing technologies, an increasing number of aberrantly expressed long-non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) have been identified in various types of cancer. lncRNAs and circRNAs are now well-established tumor-influencing factors in cancer, driving not only tumor proliferation and invasion, but also cancer progression, drug resistance and metastatic recurrence. The majority of lncRNAs and circRNAs influence cancer progression by targeting microRNAs (miRNAs/miRs). miR-10a and miR-10b, key members of the miR-10 family, have been shown to play important regulatory roles in cell proliferation, differentiation to cancer progression, and development. Manual evaluation and grouping according to different types of competing endogenous RNA and tumor was performed. The review outlined the current state of knowledge on the regulation of miR-10 family-related lncRNAs and circRNAs. The involvement of lncRNAs and circRNAs in the biogenesis, maturation and function of malignant tumors through the miR-10 family, and the key gene targets and signaling cascades that lncRNAs and circRNAs regulate through the miR-10 family were summarized. Based on the findings of this review, it can be hypothesized that lncRNAs and circRNAs targeting the miR-10 family may serve as diagnostic/prognostic markers and/or therapeutic targets for the management of cancer.

Long Non-Coding RNA SNHG4 Expression in Women with Endometriosis: A Pilot Study

BACKGROUND

Endometriosis is a chronic disease of the genital organs that mainly affects women of reproductive age. The analysis of long non-coding RNA (lncRNA) in endometriosis is a novel field of science. Recently, attention has been drawn to SNHG4, which is incorrectly expressed in various human diseases, including endometriosis.

AIM

The aim of this pilot study was to analyze the expression of lncRNA small nucleolar RNA host gene 4 (SNHG4) and to investigate its significance in endometriosis.

MATERIAL AND METHODS

LncRNA SNHG4 expression was investigated in paraffin blocks in endometriosis patients (n = 100) and in endometriosis-free controls (n = 100) using a real-time PCR assay.

RESULTS

This study revealed a higher expression of SNHG4 in endometriosis patients than in controls. A statistically significant relationship between expression level and SNHG4 was found in relation to The Revised American Society for Reproductive Medicine classification of endometriosis, 1996, in the group of patients with endometriosis.

CONCLUSION

This pilot study has revealed that gene expression in SNHG4 plays an important role in the pathogenesis of endometriosis.

MicroRNA-10 Family Promotes the Epithelial-to-Mesenchymal Transition in Renal Fibrosis by the PTEN/Akt Pathway

Renal fibrosis (RF) is a common reason for renal failure, and epithelial-mesenchymal transition (EMT) is a vital mechanism that promotes the development of RF. It is known that microRNA-10 (miR-10) plays an important role in cancer EMT; however, whether it takes part in the EMT process of RF remains unclear. Therefore, we established an in vivo model of unilateral ureteral obstruction (UUO), and an in vitro model using TGF-β1, to investigate whether and how miR-10a and miR-10b take part in the EMT of RF. In addition, the combinatorial effects of miR-10a and miR-10b were assessed. We discovered that miR-10a and miR-10b are overexpressed in UUO mice, and miR-10a, miR-10b, and miRs-10a/10b knockout attenuated RF and EMT in UUO-treated mouse kidneys. Moreover, miR-10a and miR-10b overexpression combinatorially promoted RF and EMT in TGF-β1-treated HK-2 cells. Inhibiting miR-10a and miR-10b attenuated RF and EMT induced by TGF-β1. Mechanistically, miR-10a and miR-10b suppressed PTEN expression by binding to its mRNA3'-UTR and promoting the Akt pathway. Moreover, PTEN overexpression reduced miR-10a and miR-10b effects on Akt phosphorylation (p-Akt), RF, and EMT in HK-2 cells treated with TGF-β1. Taken together, miR-10a and miR-10b act combinatorially to negatively regulate PTEN, thereby activating the Akt pathway and promoting the EMT process, which exacerbates RF progression.

The Regulatory Mechanisms and Clinical Significance of Lnc SNHG4 in Cancer

BACKGROUND

LncRNAs have been reported to be involved in a variety of biological functions, including gene expression, cell growth, and differentiation. They may also serve as oncogenes or tumor suppressor genes in diseases. lncRNAs that can encode small nucleolar RNAs (snoRNAs) have been named small nucleolar RNA host genes (SNHGs).

OBJECTIVE

In this review article, we readily review the regulatory mechanisms and clinical significance of Lnc SNHG4 in cancer.

METHODS

We systematically investigated databases, like Scopus, PubMed, Embase, Google Scholar, and Cochrane Library database for all research articles, and have provided an overview regarding the biological functions and mechanisms of lncRNA SNHG4 in tumorigenesis.

RESULTS

Compared to neighboring normal tissues, SNHG4 is significantly dysregulated in various tumor tissues. SNHG4 upregulation is mainly associated with advanced tumor stage, tumor size, TNM stage, and decreased overall survival. In addition, aberrant SNHG4 expression promotes cell proliferation, metastasis, migration, and invasion of cancer cells.

CONCLUSION

SNHG4 may serve as a new therapeutic target and prognostic biomarker in patients with cancer.

Small but strong: Pivotal roles and potential applications of snoRNAs in hematopoietic malignancies

Small nucleolar RNAs (snoRNAs) belong to a family of noncoding RNAs that are 60-300 nucleotides in length, and they are classified into two classes according to their structure and function: C/D box snoRNAs, playing an essential role in 2’-O-methylation modification on ribosomal RNA; H/ACA box snoRNAs, involved in the pseudouridylation of rRNA. SnoRNAs with unclear functions, no predictable targets, and unusual subcellular locations are called orphan snoRNAs. Recent studies have revealed abnormal expression and demonstrated the pivotal roles of snoRNAs and their host genes in various types of hematological malignancies. This review discusses recent discoveries concerning snoRNAs in a variety of hematological malignancies, including multiple myeloma, lymphoma and leukemia, and sheds light on the application of snoRNAs as diagnostic and prognostic markers as well as therapeutic targets of hematological malignancies in the future.

Non-coding RNAs and macrophage interaction in tumor progression

The macrophages are abundantly found in TME and their M2 polarization is in favor of tumor malignancy. On the other hand, non-coding RNAs (ncRNAs) can modulate macrophage polarization in TME to affect cancer progression. The miRNAs can dually induce/suppress M2 polarization of macrophages and by affecting various molecular pathways, they modulate tumor progression and therapy response. The lncRNAs can affect miRNAs via sponging and other molecular pathways to modulate macrophage polarization. A few experiments have also examined role of circRNAs in targeting signaling networks and affecting macrophages. The therapeutic targeting of these ncRNAs can mediate TME remodeling and affect macrophage polarization. Furthermore, exosomal ncRNAs derived from tumor cells or macrophages can modulate polarization and TME remodeling. Suppressing biogenesis and secretion of exosomes can inhibit ncRNA-mediated M2 polarization of macrophages and prevent tumor progression. The ncRNAs, especially exosomal ncRNAs can be considered as non-invasive biomarkers for tumor diagnosis.

Circular RNA circ_0040823 inhibits the proliferation of acute myeloid leukemia cells and induces apoptosis by regulating miR-516b/PTEN

OBJECTIVE

Endogenous circular RNAs (circRNAs) and microRNAs (miRNAs) have been shown to regulate the pathogenesis of acute myeloid leukemia (AML). The current study aimed to identify the role of circRNA 0040823 (circ_0040823) in AML.

METHODS

Microarray datasets were analyzed to identify differentially expressed circRNAs in AML patients. Peripheral blood samples were obtained from healthy volunteers and AML patients for the measurement of circ_0040823 and miR-516b levels. The overexpression or knockdown of a target gene in AML cells was achieved by the transfection with lentiviral vectors or small interfering RNAs. BALB/c nude mice were inoculated with AML cells and monitored for tumor growth. Dual-luciferase reporter assay, RNA immunoprecipitation, and RNA pull-down assay were used to determine the binding relationship between circRNA and miRNA.

RESULTS

circ_0040823 was significantly downregulated in AML patients and leukemia cells. Overexpression of circ_0040823 inhibited AML cell proliferation, and induced apoptosis and cell cycle arrest. Upregulation of circ_0040823 also repressed the growth of xenograft tumors in vivo. circ_0040823 acted as a miR-516b sponge and regulated key cellular events in leukemia cells via downregulating miR-516b. Moreover, tumor suppressor phosphatase and tensin homolog (PTEN) was a downstream target of miR-516b. The inhibition of miR-516b impaired the proliferation capacity of leukemia cells and induced apoptosis, while PTEN deficiency attenuated these effects.

CONCLUSION

This study showed that circ_0040823 inhibited proliferation and induced apoptosis of AML cells by sponging miR-516b, thereby diminishing the regulatory effect of miR-516b on PTEN. These findings identified circ_0040823/miR-516b/PTEN as a new therapeutic target for AML.

Long noncoding RNA SNHG4: a novel target in human diseases

Recently, long noncoding RNAs (lncRNAs) have attracted great attention from researchers. LncRNAs are non-protein-coding RNAs of more than 200 nucleotides in length. Multiple studies have been published on the relationship between lncRNA expression and the progression of human diseases. LncRNA small nucleolar RNA host gene 4 (SNHG4), a member of the lncRNA SNHG family, is abnormally expressed in a variety of human diseases, including gastric cancer, renal cell carcinoma, glioblastoma, neuroblastoma, prostate cancer, colorectal cancer, osteosarcoma, cervical cancer, liver cancer, lung cancer, non-small-cell lung cancer, neonatal pneumonia, diabetic retinopathy, neuropathic pain, acute cerebral infarction, acute myeloid leukaemia, and endometriosis. In this paper, the structure of SNHG4 is first introduced, and then studies in humans, animal models and cells are summarized to highlight the expression and function of SNHG4 in the above diseases. In addition, the specific mechanism of SNHG4 as a competing endogenous RNA (ceRNA) is discussed. The findings indicate that SNHG4 can be used as a biomarker for disease prognosis evaluation and as a potential target for disease diagnosis and treatment.

Long noncoding RNAs: A novel insight in the leukemogenesis and drug resistance in acute myeloid leukemia

Acute myeloid leukemia (AML) is a common hematological disorder with heterogeneous nature that resulted from blocked myeloid differentiation and an enhanced number of immature myeloid progenitors. During several decades, different factors, including cytogenetic, genetic, and epigenetic have been reported to contribute to the pathogenesis of AML by inhibiting the differentiation and ensuring the proliferation of myeloid blast cells. Recently, long noncoding RNAs (lncRNAs) have been considered as potential diagnostic, therapeutic, and prognostic factors in different human malignancies including AML. Altered expression of lncRNAs is correlated with the transformation of hematopoietic stem and progenitor cells into leukemic blast cells because of their distinct role in the key cellular processes. We discuss the significant role of lncRNAs in the proliferation, survival, differentiation, leukemic stem cells in AML and their involvement in different molecular pathways (insulin-like growth factor type I receptor, FLT3, c-KIT, Wnt, phosphatidylinositol 3-kinase/protein kinase-B, microRNAs), and associated mechanisms such as autophagy, apoptosis, and glucose metabolism. In addition, we aim to highlight the role of lncRNAs as reliable biomarkers for diagnosis, prognosis, and drug resistance for precision medicine in AML.

Construction and analysis of the abnormal lncRNA-miRNA-mRNA network in hypoxic pulmonary hypertension

The incidence of hypoxic pulmonary hypertension (HPH) is increasing. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) play an important role in HPH, but the functions and mechanism have yet to be fully elucidated. In the present study, we established a HPH rat model with 8 h of hypoxia exposure (10% O2) per day for 21 days. High-throughput sequencing identified 60 differentially expressed (DE) lncRNAs, 20 DE miRNAs and 695 DE mRNAs in rat lung tissue. qRT-PCR verified the accuracy of the results. The DE mRNAs were significantly enriched in immune response, inflammatory response, leukocyte migration, cell cycle, cellular response to interleukin-1, IL-17 signalling pathway, cytokine-cytokine receptor interaction and Toll-like receptor signalling pathway. According to the theory of competing endogenous RNA (ceRNA) networks, lncRNA-miRNA-mRNA network was constructed by Cytoscape software, 16 miRNAs and 144 mRNAs. The results suggested that seven DE lncRNAs (Ly6l, AABR07038849.2, AABR07069008.2, AABR07064873.1, AABR07001382.1, AABR07068161.1 and AABR07060341.2) may serve as molecular sponges of the corresponding miRNAs and play a major role in HPH.

Regulatory role of microRNAs on PTEN signaling

Phosphatase and tensin homolog (PTEN) gene encodes a tumor suppressor protein which is altered in several malignancies. This protein is a negative regulator of the PI3K/AKT signaling. Several transcription factors regulate the expression of PTEN in positive or negative directions. Moreover, numerous microRNAs (miRNAs) have functional interactions with PTEN and inhibit its expression. Suppression of PTEN can attenuate the response of cancer cells to chemotherapeutic agents. Based on the critical role of this tumor suppressor gene, the identification of negative regulators of its expression has practical significance particularly in the prevention and management of cancer. Meanwhile, the interaction between miRNAs and PTEN has functional consequences in non-malignant disorders including myocardial infarction, osteoporosis, cerebral ischemic stroke, and recurrent abortion. In the present review, we describe the role of miRNAs in the regulation of expression and activity of PTEN.