Long noncoding RNA SOX21-AS1 regulates the progression of triple-negative breast cancer through regulation of miR-520a-5p/ORMDL3 axis

Emerging role of miR-520a in human diseases

hsa-miR-520a is derived from MIR520A located at 19q13.42 and has a significant part in the development of various disorders, including different types of cancers, recurrent pregnancy loss, cerebral ischemia/reperfusion injury, and sciatica. In relation to cancer, numerous studies have presented diverse findings regarding the function of this particular miRNA. To summarize, it has been observed to be down-regulated in pancreatic cancer, glioma, ovarian cancer, cervical cancer, uterine corpus endometrial carcinoma, lung cancer, and acute myeloid leukemia. The purpose of this review is to offer an inclusive overview of the role of has-miR-520a in these disorders, with a specific focus on its target mRNAs in each setting and the deregulated signaling pathways involved. Additionally, we aimed to summarize the implication of miR-520a as a prognostic factor in malignancies. Finally, we performed comprehensive in-silico analyses to uncover the biological roles of this miRNA and introducing innovative concepts for future research endeavors.

Long non-coding RNA SOX21-AS1: A potential tumor oncogene in human cancers

Emerging data have proposed that the aberrant level of long noncoding RNAs (lncRNA) is related to the onset and progression of cancer. Among them, lncRNA SOX21-AS1 was shown to upregulate and seem to be a novel oncogene in various cancer, including ovarian cancer, lung cancer, breast cancer, pancreatic cancer, osteosarcoma, and melanoma. Available data indicated that SRY-box transcription factor 21 antisense divergent transcript 1 (SOX21-AS1) mostly acts as a competing endogenous RNA (ceRNA) to inhibit the level of its target microRNAs (miRNAs), leading to upregulation of their targets. In addition, SOX21-AS1 is engaged in various signaling pathways like transforming growth factor-β (TGF-β) signaling, Wnt signaling, and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling. Moreover, this lncRNA was revealed to be correlated with the clinicopathological features of affected patients. SOX21-AS1 was also proved to enhance the resistance of ovarian cancer cells to cisplatin chemotherapy. SOX21-AS1 is markedly associated with poor prognosis and low survival of patients, proposing that it may be a prognostic and diagnostic biomarker in cancer. Overexpression of SOX21-AS1 is related to various cancer-related pathways, like epithelial mesenchymal transition (EMT), invasion, migration, apoptosis, and cell cycle arrest. In this work, we aimed to discuss the biogenesis, function, and underlying molecular mechanism of SOX21-AS1 in cancer progression as well as its potential as a prognostic and diagnostic biomarker in human cancers.

Roles and Mechanisms of Long Non-Coding RNAs in Breast Cancer

Breast cancer is a major health threat and the second leading cause of cancer-related deaths in women worldwide. The detailed mechanisms involved in the initiation and progression of breast cancer remain unclear. In recent years, amounting evidence indicated that long non-coding RNAs (lncRNAs) played crucial roles in regulating various biological processes and malignancy tumors, including breast cancer. In this review, we briefly introduce the functions and underlying mechanisms by which lncRNAs are involved in breast cancer. We summarize the roles of the lncRNAs in regulating malignant behaviors of breast cancer, such as cell proliferation, migration and invasion, epithelial-mesenchymal transition (EMT), apoptosis, and drug resistance. Additionally, we also briefly summarize the roles of circular RNAs (circRNAs) in breast cancer carcinogenesis.

LncRNA VPS9D1-AS1 Sponging miR-520a-5p Contributes to the Development of Uterine Corpus Endometrial Carcinoma by Enhancing BIRC5 Expression

The pattern of VPS9D1-AS1 expression and its effects on uterine corpus endometrial carcinoma (UCEC) remained unclear. VPS9D1-AS1, miR-520a-5p, and BIRC5 mRNA levels were quantified by qRT-PCR. Bax, Bcl-2, N-cadherin, E-cadherin, and BIRC5 protein levels were analyzed through western blotting. Cell migration, invasion, proliferation, as well as apoptosis of cells were checked after performing assay for wound-healing, Transwell, cell-counting kit-8 (CCK-8) assay, and western blotting. VPS9D1-AS1 effects on UCEC were observed in nude mice. Through bioinformatics tools, we analyzed the association present among miR-520a-5p, BIRC5, and VPS9D1-AS1 along with RNA immunoprecipitation, and Dual-Luciferase verification reporter analysis. Our findings suggested VPS9D1-AS1 gene expression was up-regulated in both tissues as well as cells of UCEC. VPS9D1-AS1 knockdown suppressed migration, invasion, epithelial-mesenchymal transition (EMT) along with proliferation of UCEC cells, caused in vitro cell apoptosis initiation, and in vivo reduction of tumor growth. Mechanistically, it was verified that VPS9D1-AS1 targeted BIRC5 and caused miR-520a-5p sponging. Inhibitor of miR-520-5p markedly reversed the anti-tumor effects of VPS9D1-AS1 knockdown or BIRC5 knockdown on UCEC progression. Our studies revealed that VPS9D1-AS1 contributed to the UCEC development and progression by binding to miR-520a-5p competitively and inducing BIRC5 expression, indicating that VPS9D1-AS1 might act as a therapeutic target to develop new therapies for UCEC patients.

LncRNA UCA1 promotes SOX12 expression in breast cancer by regulating m6A modification of miR-375 by METTL14 through DNA methylation

Breast cancer, a multifactorial disease, represents one of the leading causes of cancer-related morbidity and mortality in women. This study set out to elucidate the underlying mechanism by which lncRNA UCA1 affects the m⁶A modification of miR-375 by mediating the DNA methylation of METTL14 and then altering SOX12 expression in breast cancer. First, the expression patterns of lncRNA UCA1, miR-375, and apoptosis-related factors were quantitated by means of RT-qPCR and western blot analysis. In addition, the proliferation, invasion, and apoptosis of cells were detected using CCK-8, Transwell, and flow cytometry, respectively. RIP was performed to further uncover the interaction of lncRNA UCA1 and DNA methyltransferases, and MSP was employed for METTL14 promoter region methylation. The DNA methyltransferase enrichment in the METTL14 promoter region was measured by ChIP. The targeting relationship between miR-375 and SOX12 was confirmed by bioinformatics analysis and dual-luciferase report assay. Lastly, the aforementioned mechanism was also verified using tumor xenograft in vivo. It was found the elevated lncRNA UCA1 expression levels serve as a risk factor of poor prognosis in breast cancer. Meanwhile, silencing lncRNA UCA1 could inhibit the proliferation and invasion, but promote apoptosis of breast cancer cells by reducing the DNA methylation of METTL14 and augmenting its expression. Furthermore, METTL14 was observed to mediate the low miR-375 expression through m⁶A modification, leading to increased SOX12 expression levels in breast cancer. Altogether, findings obtained in our study indicated that silencing lncRNA UCA1 curbed the progression of breast cancer through the METTL14-miR-375-SOX12 axis.

Role of microRNA/lncRNA Intertwined With the Wnt/β-Catenin Axis in Regulating the Pathogenesis of Triple-Negative Breast Cancer

Objective (s): In this mini-review, we aimed to discuss the Wnt/β-catenin signaling pathway modulation in triple-negative breast cancer, particularly the contribution of lncRNAs and miRNAs in its regulation and their possible entwining role in breast cancer pathogenesis, proliferation, migration, or malignancy.

Background: Malignant tumor formation is very high for breast cancer in women and is a leading cause of death all over the globe. Among breast cancer subtypes, triple-negative breast cancer is rife in premenopausal women, most invasive, and prone to metastasis. Complex pathways are involved in this cancer’s pathogenesis, advancement, and malignancy, including the Wnt/β-catenin signaling pathway. This pathway is conserved among vertebrates and is necessary for sustaining cell homeostasis. It is regulated by several elements such as transcription factors, enhancers, non-coding RNAs (lncRNAs and miRNAs), etc.

Methods: We evaluated lncRNAs and miRNAs differentially expressed in triple-negative breast cancer (TNBC) from the cDNA microarray data set literature survey. Using in silico analyses combined with a review of the current literature, we anticipated identifying lncRNAs and miRNAs that might modulate the Wnt/β-catenin signaling pathway.

Result: The miRNAs and lncRNAs specific to triple-negative breast cancer have been identified based on literature and database searches. Tumorigenesis, metastasis, and EMT were all given special attention. Apart from cross-talk being essential for TNBC tumorigenesis and treatment outcomes, our results indicated eight upregulated and seven downregulated miRNAs and 19 upregulated and three downregulated lncRNAs that can be used as predictive or diagnostic markers. This consolidated information could be useful in the clinic and provide a combined literature resource for TNBC researchers working on the Wnt/β-catenin miRNA/lncRNA axis.

Conclusion: In conclusion, because the Wnt pathway and miRNAs/lncRNAs can modulate TNBC, their intertwinement results in a cascade of complex reactions that affect TNBC and related processes. Their function in TNBC pathogenesis has been highlighted in molecular processes underlying the disease progression.

Circ_0060551 promotes the migration and invasion of cervical cancer by Up-regulating TPD52

PROBLEM

Cervical cancer has been recognized as the second most common cancer in women worldwide. Previous studies have reported that some circular RNAs (circRNAs) can influence the progression of cervical cancer. However, more researches are still required to unveil the underlying mechanism of how circRNAs regulate the progression of such cancer. We aimed at unveiling the mechanism of how circ_0060551 effected the progression of cervical cancer.

METHOD OF STUDY

RT-qPCR and western blot assays were used to detect the expression and protein levels. Mechanism experiments were conducted to investigate the relationship among circ_0060551, TPD52, miR-520a-5p and ELAVL1. Rescue assays were mainly carried out to verify how circ_0060551 influenced the migration and invasion of cervical cancer cells.

RESULTS

According to the results, circ_0060551 was up-regulated in cervical cancer cells and could promote the migration and invasion of cells via TPD52. In addition, circ_0060551 could up-regulate TPD52 expression through a ceRNA model to target miR-520a-5p. Moreover, circ_0060551 could stabilize the mRNA expression of TPD52 via recruiting ELAVL1.

CONCLUSION

Our study proved that circ_0060551 could promote the migration and invasion of cervical cancer cells. This article is protected by copyright. All rights reserved.

Hsa_circRNA_0017620 regulated cell progression of non-small-cell lung cancer via miR-520a-5p/KRT5 axis

Background

CircRNA is a very important functional RNA that plays an important role in the development and metabolism of cancer. However, the study of circRNA in NSCLC has not been fully elucidated.

Methods

The expression of hsa_circ_0017620, SFMBT2, miR‐520a‐5p, and KRT5 was determined using qRT‐PCR. KRT5, Twist1, E‐cadherin, and Ki67 protein expression were measured with western blot. The positive expression rates of Ki67 and Vimentin were determined by immunohistochemistry assay. 5‐Ethynyl‐2’‐deoxyuridine (EdU), colony formation, and MTT assays were used to assess cell proliferation. Transwell migration and invasion assay were applied to determine cell migration and invasion. Dual‐luciferase reporter and RNA immunoprecipitation assays were used to verify the relationship among hsa_circ_0017620, miR‐520a‐5p, and KRT5. The animal experiment was used to ensure the effects of hsa_circ_0017620 on tumor growth in vivo.

Results

Hsa_circ_0017620 was upregulated in NSCLC cells and tissues. MiR‐520a‐5p had been verified to be a target miRNA of hsa_circ_0017620 and KRT5 had been verified to be a target mRNA of miR‐520a‐5p in NSCLC cells. Knockdown of hsa_circ_0017620 inhibited cell proliferation, migration, and invasion in NSCLC cells, which was reversed by downregulating miR‐520a‐5p or upregulating KRT5 in NSCLC. Overexpression of hsa_circ_0017620 had opposite effects in NSCLC. Moreover, hsa_circ_0017620 silencing inhibited tumor growth in vivo of NSCLC.

Conclusion

In this study, we found that hsa_circ_0017620 played an important role in NSCLC progression. Hsa_circ_0017620 regulated cell proliferation, invasion, and migration through targeting miR‐520a‐5p/KRT5 axis in NSCLC, providing a potential new target for the treatment and diagnosis of NSCLC.

The microRNA-520a-3p inhibits invasion and metastasis by targeting NF-kappaB signaling pathway in non-small cell lung cancer

PURPOSE

To identify the expression of miR-520a-3p and AKT1 in non-small cell lung cancer cells (NSCLC) and the mechanism in inhibiting cell invasion and metastasis by targeting NF-kappaB signaling pathway.

METHODS

Bioinformatics analysis and dual luciferase reporter gene assay were used to predict and verify the targeting relationship between miR-520a-3p and AKT1. EdU assay was used to detect the proliferation of NSCLC cells. Flow cytometry detected the apoptosis of NSCLC cells. Transwell assay tested the invasion ability of NSCLC cells. qRT-PCR measured the expression of miR-520a-3p and AKT1 mRNA in NSCLC cells; while western blotting was adopted to detect the protein expressions of AKT1, Ki67, CyclinD1, Bax, Bcl-2, MMP-2, MMP-9, NF-kB p65, IkBs kinase (IKK), NF-kB inducing kinase (NIK).

RESULTS

Bioinformatics analysis suggested that miR-520a-3p could target AKT1. miR-520a-3p could regulate the expression of AKT1 negatively. Compared to mimic-NC group, miR-520a-3p mimic group had increased expressions of miR-520a-3p and Bax, while decreased expressions of AKT1, Ki67, CyclinD1, Bcl-2, MMP-2, MMP-9, NF-kB p65, IKK and NIK, reduced cell proliferation, invasion, and increased cell apoptosis rate (all P < 0.05). Compared to inhibitor NC group, miR-520a-3p inhibitor group had decreased expressions of miR-520a-3p and Bax, but increased expressions of AKT1, Ki67, CyclinD1, Bcl-2, MMP-2, MMP-9, NF-kB p65, IKK and NIK, promoted cell proliferation, invasion, and suppressed cell apoptosis rate (all P < 0.05).

CONCLUSION

Overexpression of miR-520a-3p can target and downregulate the expression of AKT1 to inhibit the invasion and metastasis of NSCLC via suppressing the activation of NF-kappaB signaling pathway.

The functional significance and cross-talk of non-coding RNAs in triple negative and quadruple negative breast cancer

One of the leading causes of cancer-related deaths worldwide is breast cancer, among which triple-negative breast cancer (TNBC) is the most malignant and lethal subtype. This cancer accounts for 10-20% of all breast cancer deaths. Proliferation, tumorigenesis, and prognosis of TNBC are affected when the androgen receptor (AR) is not expressed, and it is classified as quadruple negative breast cancer (QNBC). Non-coding RNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play a significant role in tumorigenesis by virtue of their oncogenic and tumor-suppressive properties. To regulate tumorigenesis, miRNAs interact with their target mRNAs and modulate their expression, whereas lncRNAs can either act alone or interact with miRNAs or other molecules through various signaling pathways. Conversely, circRNAs regulate tumorigenesis by acting as miRNA sponges predominantly. Recently, non-coding RNAs were studied comprehensively for their roles in tumor proliferation, progression, and metastasis. As a result of existing studies and research progress, non-coding RNAs have been implicated in TNBC, necessitating their use as biomarkers for future diagnostic applications. In this review, the non-coding RNAs are explicitly implicated in the regulation of breast cancer, and their cross-talk between TNBC and QNBC is also discussed.

Long non‑coding RNA LINC01748 exerts carcinogenic effects in non‑small cell lung cancer cell lines by regulating the microRNA‑520a‑5p/HMGA1 axis

The important functions of long non‑coding RNAs in the malignancy of non‑small cell lung cancer (NSCLC) has been increasingly highlighted. However, whether LINC01748 functions in a crucial regulatory role still requires further research. The aim of the present study was to investigate the biological roles of LINC01748 in NSCLC. Furthermore, different experiments were utilized to investigate the mechanism of action of LINC01748 in 2 NSCLC cell lines. Reverse transcription‑quantitative PCR was used to measure mRNA expression levels. Cell Counting Kit‑8 assay, flow cytometry analysis and Transwell and Matrigel assays were also used to analyze, cell viability, apoptosis, and migration and invasion, respectively. A tumor xenograft model was used for in vivo experiments. RNA immunoprecipitation experiments, luciferase reporter assays and rescue experiments were used to investigate the mechanisms involved. Data from The Cancer Genome Atlas dataset and patients recruited into the present study showed that LINC01748 was overexpressed in NSCLC. Patients with high LINC01748 mRNA expression level had shorter overall survival rate compared with that in patients with low LINC01748 mRNA expression level. Then, knockdown of LINC01748 mRNA expression level reduced cell proliferation, migration and invasion, but increased cell apoptosis in vitro. Knockdown of LINC01748 also reduced tumor growth in vivo. Mechanistically, LINC01748 could act as a competing endogenous (ce)RNA to sponge microRNA(miR)‑520a‑5p, to increase the expression level of the target gene, high mobility group AT‑hook 1 (HMGA1) in the NSCLC cell lines. Furthermore, rescue experiments illustrated that the functions exerted by LINC01748 knockdown were negated by miR‑520a‑5p inhibition or HMGA1 overexpression. In summary, LINC01748 acted as a ceRNA by sponging miR‑520a‑5p, leading to HMGA1 overexpression, thus increasing the aggressiveness of the NSCLC cells. Accordingly, targeting the LINC01748/miR‑520a‑5p/HMGA1 pathway may benefit NSCLC therapy.

RETRACTED: Zinc moderates circular RNA CircFOXP1 expression in order to regulate ferroptosis during lung adenocarcinoma

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. After a thorough investigation, the Editor has concluded that the acceptance of this article was partly based upon the positive advice of one illegitimate reviewer report. The report was submitted from an email account which was provided to the journal as a suggested reviewer during the submission of the article. Although purportedly a real reviewer account, the Editor has concluded that this was not of an appropriate, independent reviewer. This manipulation of the peer-review process represents a clear violation of the fundamentals of peer review, our publishing policies, and publishing ethics standards. Apologies are offered to the reviewer whose identity was assumed and to the readers of the journal that this deception was not detected during the submission process. Also, a section of the ‘circFOXP1/Merge’ panel from Fig. 1B appears similar to a section of the ‘18s/Merge’ panel from Figure 1B of the article.

Long non-coding RNA GAS6-AS1 enhances breast cancer cell aggressiveness by functioning as a competing endogenous RNA of microRNA-215-5p to enhance SOX9 expression

Long non-coding (lnc) RNAs play crucial functions in human cancer. However, until recently, the involvement of the lncRNA GAS6-AS1 in breast cancer (BCa) malignancy has not been studied exhaustively. The roles and underlying mode of action of GAS6-AS1 action in BCa progression were examined through functional experiments. A decline in GAS6-AS1 level led to a significant decrease in BCa cell proliferation, and the ability for colony formation. Here, GAS6-AS1 competed as endogenous RNA by sequestering microRNA-215-5p (miR-215-5p) causing an enhanced expression of SRY-box transcription factor 9 (SOX9). The effects of silencing GAS6-AS1 on BCa malignant phenotypes could be ameliorated by inhibiting miR-215-5p or restoring SOX9. Thus, GAS6-AS1 acted as a lncRNA that drives tumor in BCa, and enabled progression of BCa through miR-215-5p /SOX9 axis regulation. These outcomes show that the GAS6-AS1/miR-215-5p/SOX9 axis is a potentially effective target for cancer treatment and management.

Long non-coding RNA SOX21-AS1 modulates lung cancer progress upon microRNA miR-24-3p/PIM2 axis

Lung cancer is a lethal cancer that threatens human health. Several studies have demonstrated the role of long non-coding RNAs (lncRNAs) in lung cancer. SOX21-AS1 is a newly discovered oncogenic lncRNA, but its molecular mechanism in lung cancer is not known. Here, the levels of SOX21-AS1, miR-24-3p, and PIM2 were examined in lung cancer and normal tissues. The relationships between miR-24-3p and SOX21-AS1 or PIM2 were predicted using bioinformatics tools and confirmed using a luciferase reporter assays. Colony formation, MTT, flow cytometry, and transwell assays were conducted to analyze cell proliferation, apoptosis, migration, and invasion abilities, respectively. Western blotting was used to measure PIM2 expression levels in cancer tissues and cells. SOX21-AS1 expression levels were high in lung cancer tissues and cells. In contrast, the amount of miR-24-3p bound to SOX21-AS1 was relatively low in cancerous tissues and cells. The knockdown of SOX21-AS1 decreased cell proliferation, activated apoptosis, and promoted cell migration and invasion. These effects were abolished by miR-24-3p inhibition. The oncogenic function of SOX21-AS1 mediated through targeting miR-24-3p was also demonstrated in animal models. PIM2 was targeted by miR-24-3p and showed increased levels in tumor tissues and cells. Furthermore, miR-24-3p overexpression inhibited the proliferation and promoted the apoptosis of lung cancer cells. In lung cancer cells, SOX21-AS1 negatively modulated the miR-24-3p/PIM2 axis to facilitate their proliferation, migration, and invasion. These findings offer a novel idea for future research on treating lung cancer at the molecular level.

Multifaceted roles of long non-coding RNAs in triple-negative breast cancer: biology and clinical applications

Triple-negative breast cancer (TNBC) is a heterogeneous breast cancer subtype that lacks targeted therapy due to the absence of estrogen, progesterone, and HER2 receptors. Moreover, TNBC was shown to have a poor prognosis, since it involves aggressive phenotypes that confer significant hindrance to therapeutic treatments. Recent state-of-the-art sequencing technologies have shed light on several long non-coding RNAs (lncRNAs), previously thought to have no biological function and were considered as genomic junk. LncRNAs are involved in various physiological as well as pathological conditions, and play a key role in drug resistance, gene expression, and epigenetic regulation. This review mainly focuses on exploring the multifunctional roles of candidate lncRNAs, and their strong association with TNBC development. We also summarise various emerging research findings that establish novel paradigms of lncRNAs function as oncogenes and/or tumor suppressors in TNBC development, suggesting their role as prospective therapeutic targets.

ORMDL1 is upregulated and associated with favorable outcomes in colorectal cancer

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The association between ORMDL1 expression and clinipathological characteristic in colorectal cancer (CRC) has not been reported before, which is addressed in this study.

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Although ORMDL1 is generally upregulated in CRC, high expression of ORMDL1 is associated with longer survival; the combination of ORMDL1 expression and other biomarkers to stratify and predict prognosis in CRC is worth to explore.

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ORMDL1 seems to influence cell cytoskeleton dynamics through Rho GTPase, other than canonical EMT related transcription factors.

Background

The ORMDL1 gene is known as a crucial negative regulator of sphingolipid biogenesis. However, the ORMDL1 gene has rarely been studied in a tumor-related context. Therefore, its prognostic value and functional significance in colorectal cancer (CRC) remain to be explored.

Methods

TCGA CRC cohort analysis, qRT-PCR, and immunohistochemistry (IHC) were used to examine the ORMDL1 expression level. The association between ORMDL1 expression and various clinical characteristics was analyzed by chi-square tests. The overall survival (OS) of CRC patients was analyzed by Kaplan-Meier analysis. In vitro and in vivo cell-based assays were performed to explore the role of ORMDL1 in cell proliferation, invasion and migration. Transcriptional changes in cells with either ORMDL1 knockdown or overexpression were compared and analyzed.

Results

ORMDL1 was upregulated in CRC tissues in both the TCGA and our cohort. Interestingly, its expression was significantly lower in patients with metastasis than in patients without metastasis, and the high expression group had longer OS than the low expression group. Knockdown of ORMDL1 expression can promote proliferation, colony formation and invasion, while attenuating migration in CRC cell lines. In contrast, forced overexpression of ORMDL1 reduced cell proliferation, colony formation and invasion, while enhancing cell migration. Stable knockdown of ORMDL1 can promote cancer cell proliferation in vivo to some extent. Finally, Rho GTPase activity was influenced by ORMDL1, and the expression of ORMDL1 was enhanced by DTT treatment.

Conclusion

ORMDL1 is upregulated and may serve as a biomarker to predict favourable outcomes in colorectal cancer.

SRY-Box 21 Antisense RNA 1 Knockdown Diminishes Amyloid Beta25-35-Induced Neuronal Damage by miR-132/PI3K/AKT Pathway

Our study aimed to explore the function and mechanism of action of long noncoding RNA (lncRNA) SRY-Box 21 antisense RNA 1 (SOX21-AS1) in amyloid beta_25-35 (Aβ_25-35)-induced neuronal damage. To induce neuronal damage, neuronal cells and differentiated IMR-32 neuroblastoma cells were challenged by Aβ_25-35. SOX21-AS1 and miR-132 quantities were detected by quantitative reverse transcription polymerase chain reaction. Cell damage was evaluated by detecting the changes of cell viability, apoptosis, and oxidative stress. Cell viability was measured using cell counting kit-8. Cell apoptosis was evaluated by flow cytometry and caspase-3 activity. The oxidative stress was analyzed by reactive oxygen species level. The expression of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was examined by western blot. SOX21-AS1 abundance was up-regulated in Aβ_25-35-challenged neuronal cells. Silencing of SOX21-AS1 attenuated Aβ_25-35-induced viability reduction and promotion of apoptosis and oxidative stress, suggesting that silencing of SOX21-AS1 repressed Aβ_25-35-induced neuronal damage. miR-132 quantity was reduced in Aβ_25-35-challenged neuronal cells, and negatively controlled by SOX21-AS1. miR-132 knockdown abolished the effect of SOX21-AS1 silencing on Aβ_25-35-induced neuronal damage, indicating that SOX21-AS1 controls Aβ_25-35-induced neuronal damage via regulating miR-132. The PI3K/AKT signaling was repressed in Aβ_25-35-challenged cells, but this effect was counteracted upon overexpression of miR-132. In conclusion, SOX21-AS1 knockdown mitigated Aβ_25-35-dependent neuronal cell damage by promoting miR-132/PI3K/AKT pathway.

Long noncoding RNAs in triple-negative breast cancer: A new frontier in the regulation of tumorigenesis

In recent years, triple-negative breast cancer (TNBC) has emerged as the most aggressive subtype of breast cancer and is usually associated with increased mortality worldwide. The severity of TNBC is primarily observed in younger women, with cases ranging from approximately 12%-24% of all breast cancer cases. The existing hormonal therapies offer limited clinical solutions in completely circumventing the TNBC, with chemoresistance and tumor recurrences being the common hurdles in the path of TNBC treatment. Accumulating evidence has correlated the dysregulation of long noncoding RNAs (lncRNAs) with increased cell proliferation, invasion, migration, tumor growth, chemoresistance, and decreased apoptosis in TNBC. Various clinical studies have revealed that aberrant expression of lncRNAs in TNBC tissues is associated with poor prognosis, lower overall survival, and disease-free survival. Due to these specific characteristics, lncRNAs have emerged as novel diagnostic and prognostic biomarkers for TNBC treatment. However, the underlying mechanism through which lncRNAs perform their actions remains unclear, and extensive research is being carried out to reveal it. Therefore, understanding of mechanisms regulating the modulation of lncRNAs will be a substantial breakthrough in effective treatment therapies for TNBC. This review highlights the association of several lncRNAs in TNBC progression and treatment, along with their possible functions and mechanisms.

MicroRNA-520a Suppresses Pathogenesis and Progression of Non-Small-Cell Lung Cancer through Targeting the RRM2/Wnt Axis

MicroRNAs (miRNAs) regulate multiple cellular behaviors, and their aberrant expression is frequently associated with disease progression. This research focused on the effects of miR-520a on the development of non-small-cell lung cancer (NSCLC) and the molecules involved. Tumor and normal tissues from 24 patients with NSCLC were collected. Differentially expressed miRNAs between tumor tissues and normal tissues were screened using microarrays, and miR-520a was screened to be significantly poorly expressed in tumor samples. Artificial upregulation of miR-520a reduced proliferation, migration and invasion, and resistance to death of NSCLC A549 and H460 cells according to the MTT, EdU labeling, transwell, and flow cytometry assays, respectively. miR-520a upregulation suppressed growth and metastasis of xenograft tumors in vivo. The integrated bioinformatic analysis and dual luciferase assays suggested that miR-520a targeted ribonucleotide reductase subunit 2 (RRM2) mRNA and inactivated the Wnt/β-catenin signaling pathway in NSCLC cells. Upregulation of RRM2 enhanced the malignant behaviors of NSCLCs, but the oncogenic effects of RRM2 were blocked upon miR-520a overexpression. To conclude, this study evidenced that miR-520a inhibits NSCLC progression through suppressing RRM2 and the Wnt signaling pathway. This paper may offer novel insights into NSCLC treatment.

Single-cell long noncoding RNA (lncRNA) transcriptome implicates MALAT1 in triple-negative breast cancer (TNBC) resistance to neoadjuvant chemotherapy

Cumulative evidence suggests added benefit for neoadjuvant chemotherapy (NAC) in a subset of triple-negative breast cancer (TNBC) patients. Herein we identified the long noncoding RNA (lncRNA) transcriptional landscape associated with TNBC resistance to NAC, employing 1758 single cells from three extinction and three persistence TNBC patients. Using Iterative Clustering and Guide-gene Selection (ICGS) and uniform manifold approximation and projection (UMAP) dimensionality reduction analysis, we observed single cells derived from each patient to largely cluster together. Comparing the lncRNA transcriptome from single cells through the course of NAC treatment revealed minimal overlap based on lncRNA transcriptome, suggesting substantial effects of NAC on lncRNA transcription. The differential analysis revealed upregulation of 202 and downregulation of 19 lncRNAs in the persistence group, including upregulation of five different transcripts encoding for the MALAT1 lncRNA. CRISPR/Cas9-mediated MALAT1 promoter deletion in BT-549 TNBC model enhanced sensitivity to paclitaxel and doxorubicin, suggesting a role for MALAT1 in conferring resistance. Mechanistically, whole transcriptome analysis of MALAT1-KO cells revealed multiple affected mechanistic networks as well as oxidative phosphorylation canonical and angiogenesis functional category. Interestingly, lncRNA profiling of MALAT1-depleted TNBC also revealed a number of altered lncRNAs in response to MALAT1 deletion, suggesting a reciprocal relationship between MALAT1 and a number of lncRNAs, including NEAT1, USP3-AS1, and LINC-PINT, in TNBC. Elevated expression of MALAT1, USP3-AS1, and LINC-PINT correlated with worse clinical outcomes in BC patients. Our data revealed the lncRNA transactional portrait and highlighted a complex regulatory network orchestrated by MALAT1 in the context of TNBC resistance to NAC therapy.

MicroRNAs Involved in Inflammatory Breast Cancer: Oncogene and Tumor Suppressors with Possible Targets

Inflammatory breast cancer (IBC) as a rare and highly aggressive type of breast cancer displays phenotypic characteristics. To date, the IBC-associated molecular mechanisms are entirely unknown. In addition, there is an urgent need to identify the new biomarkers involved in the diagnosis and therapeutic purposes of IBC. MicroRNAs, a category of short noncoding RNAs, are capable of controlling the post-transcriptional expression of genes and thus can act as diagnostic predictive tools. In this review, we addressed the status of oncogenic and tumor suppressor miRNA-mediated IBC in current studies. Furthermore, based on their targets, their involvement in cancer progression, angiogenesis, metastasis, and apoptosis were determined.

Long Non-Coding RNA C1QTNF1 Antisense RNA 1 Upregulates Hexokinase 2 by Sponging microRNA-484 to Promote the Malignancy of Colorectal Cancer

Purpose

The long noncoding RNA C1QTNF1 antisense RNA 1 (C1QTNF1-AS1) contributes to hepatocellular carcinoma development. However, its expression and roles in colorectal cancer (CRC) have not been fully explored. Therefore, this study determined the expression and roles of C1QTNF1-AS1 in CRC and elucidated its detailed mechanism of action.

Methods

C1QTNF1-AS1 expression in CRC tissues and cell lines was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We used Cell Counting Kit-8, flow cytometry, cell migration and invasion assays, and a xenograft tumor model to test the effects of C1QTNF1-AS1 on CRC malignancy. The associations among C1QTNF1-AS1, microRNA-484 (miR-484), and hexokinase 2 (HK2) were explored using luciferase reporter assay, RNA immunoprecipitation, RT–qPCR, and Western blotting.

Results

C1QTNF1-AS1 was overexpressed in CRC and related to poor prognosis. C1QTNF1-AS1 interference inhibited CRC cell proliferation, migration, and invasion but induced apoptosis. Furthermore, C1QTNF1-AS1 deficiency impaired tumor growth in vivo. Mechanistically, C1QTNF1-AS1 adsorbed miR-484, thereby increasing the expression of its target HK2. Rescue experiments revealed that the effects of C1QTNF1-AS1 deficiency in CRC cells were reversed by inhibiting miR-484 or upregulating HK2.

Conclusion

C1QTNF1-AS1 drives CRC progression by sponging miR-484 and consequently upregulating HK2. The C1QTNF1-AS1/miR-484/HK2 pathway may serve as a diagnostic and therapeutic target for CRC.

Exosome-transferred hsa_circ_0014235 promotes DDP chemoresistance and deteriorates the development of non-small cell lung cancer by mediating the miR-520a-5p/CDK4 pathway

BACKGROUND

Circular RNAs (circRNAs) play crucial roles in the development and progression of human cancers, including non-small cell lung cancer (NSCLC). However, most of these circRNAs, such as hsa_circ_0014235, are not fully identified in functions and mechanisms.

METHODS

The isolated exosomes from serum specimens were identified using transmission electron microscopy (TEM). The expression of hsa_circ_0014235, miR-520a-5p and cyclin-dependent kinase 4 (CDK4) was detected by real-time quantitative polymerase chain reaction (qPCR). For functional assays, cell proliferation, colony formation ability, migration, invasion, cell apoptosis and cell cycle progression were determined using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay, transwell assay and flow cytometry assay, respectively. The expression of CDK4 and other indicated marker proteins was detected by western blot. The predicted target relationship between miR-520a-5p and hsa_circ_0014235 or cyclin-dependent kinase 4 (CDK4) was verified by dual-luciferase reporter assay or RNA immunoprecipitation (RIP) assay.

RESULTS

The expression of hsa_circ_0014235 was notably elevated in NSCLC serum-derived exosomes, tumor tissues and cells. NSCLC serum-derived exosomes promoted NSCLC cell resistance to cisplatin (DDP), cell proliferation, migration and invasion in vitro, as well as tumor growth and DDP resistance in vivo. Hsa_circ_0014235 overexpression enhanced DDP resistance and facilitated cell malignant behaviors. MiR-520a-5p was a target of hsa_circ_0014235, and rescue experiments showed that miR-520a-5p restoration reversed the effects of hsa_circ_0014235 overexpression. Moreover, CDK4 was a target of miR-520a-5p, and rescue experiments showed that CDK4 knockdown reversed the aggressive effects of miR-520a-5p inhibition on NSCLC progression.

CONCLUSIONS

Exosome-transmitted hsa_circ_0014235 promoted NSCLC malignant development by mediating the miR-520a-5p/CDK4 regulatory axis.

Long non-coding RNA LINC00511/miR-150/MMP13 axis promotes breast cancer proliferation, migration and invasion

Breast cancer is the most common cancer affecting women and one of the leading causes of cancer-related deaths worldwide. In existing studies, some long non-coding RNAs (lncRNAs) are considered to have important regulatory roles in the development of cancers. However, the pathogenic significance of LINC00511 in breast cancer is unclear. In this study, LINC00511 was significantly up-regulated in breast cancer, and its expression level was correlated to poor prognosis of patients with breast cancer. To further study the role of LINC00511 in breast cancer, we knocked down the expression of LINC00511 using siRNAs. Cells transfected with siRNA-2 proliferated, and its metastasis was suppressed. RNA-seq analysis revealed 182 potential targets for LINC00511. The in-silico analysis revealed that differently expressed genes were closely related to signaling mediated by p38-alpha and p38-beta. Subcellular localization showed that LINC00511 was mainly located in the cytoplasm, and knocking down the LINC00511 gene could down-regulate the expression of MMP13. Using bioinformatics analysis combined with dual-luciferase report assay, we finally determined that miR-150 was the direct target of LINC00511. The dual-luciferase report assays also showed that MMP13 was the target of miR-150. LINC00511 knockdown significantly reduced MMP13 protein levels, and miR-150 gene knockdown significantly rescued the down-regulation of MMP13 caused by LINC00511 gene silencing. Moreover, silencing MMP13 and overexpression of miR-150 could reduce the proliferation of breast cancer cells. In conclusion, our data show that LINC00511 is a breast cancer promoter, and the LINC00511/miR-150/MMP13 axis may be a new therapeutic strategy for breast cancer patients.