lncRNA PCAT18 inhibits proliferation, migration and invasion of gastric cancer cells through miR-135b suppression to promote CLDN11 expression

miR-135b: A key role in cancer biology and therapeutic targets

miR-135b, a microRNA, is consistently up-regulated in various cancer tissues and cells, promoting cancer progression. By inhibiting one or more target genes, miR-135b regulates phenotypes such as cancer growth, apoptosis, migration, invasion, drug resistance, and angiogenesis, establishing it as a critical driver of cancer progression. Additionally, miR-135b is regulated by various oncogenes and therapeutic drugs, highlighting its complexity and therapeutic potential. Significant progress has been made in understanding miR-135b's impact on cancer cell behavior, establishing it as a promising biomarker for cancer diagnosis and prognosis, as well as a potential target for future cancer therapies. However, despite the extensive research on this topic, there has been no comprehensive review summarizing its role and mechanisms across different cancer types. This review aims to provide a detailed overview of the biological characteristics of miR-135b, its regulatory targets, upstream signaling pathways, and its therapeutic potential, including its influence on cancer chemoresistance. The review also addresses key controversies surrounding miR-135b in cancer research, aiming to deepen the understanding of its role, promote the transformation of its clinical application, and provide a theoretical foundation for developing more effective cancer treatment strategies.

miR-135b: A Potential Biomarker for Pathological Diagnosis and Biological Therapy

MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs found in eukaryotes with post-transcriptional regulatory functions. A variety of miRNAs is differentially expressed in cancer tissues and thus can be used as biomarkers. microRNA-135b-5p (miR-135b) has been shown to be involved in the pathological processes of a variety of neoplastic and non-neoplastic diseases. Under different conditions, miR-135b has different tumor suppressive and carcinogenic effects. miR-135b regulates the development of cancer, including metabolism, proliferation, apoptosis, invasion, fibrosis, angiogenesis, immunomodulation, and drug resistance. miR-135b can be used as a new biomarker for tumor diagnosis and prognosis, which has the potential for clinical guidance. This article reviews the relevant research on miR-135B in the field of tumors, including the biogenesis background of miR-135b, the expression of miR-135b in tumors, and the related targets and signaling pathways of miR-135b mediating tumor progression in order to sort out and explore the clinical transformation value of miR-135b.

The role of CLDN11 in promotion of granulosa cell proliferation in polycystic ovary syndrome via activation of the PI3K-AKT signalling pathway

Polycystic ovary syndrome (PCOS) is a complex gynecological endocrinological condition that significantly impacts women's fertility during their reproductive lifespan. The causes of PCOS are multifaceted, and its pathogenesis is not yet clear. This study established a rat model of PCOS and, in conjunction with clinical samples and database data, analysed the role of claudin 11 (CLDN11) in follicular granulosa cells (GCs) in regulating the proliferation of GCs. Our findings revealed a notable decrease in the protein expression of CLDN11 within the follicular GCs of individuals with PCOS. In vitro rat cell experiments revealed that interference with CLDN11 significantly inhibited viability and increased the apoptosis of GCs. Additional research has illuminated the mechanism by which CLDN11 regulates the expression levels of CCND1 and PCNA through the PI3K/AKT signalling pathway, significantly influencing the proliferation of rat follicular GCs. Furthermore, overexpression of CLDN11 via an adeno-associated virus (AAV) vector was found to reverse the PCOS-like phenotype induced in rats by letrozole. Our findings suggest that CLDN11 stimulates the proliferation of these cells by activating the PI3K/AKT pathway, thereby increasing the expression of CCND1 and PCNA. These discoveries underscore the critical function of CLDN11 in regulating the functionality of follicular GCs, which offers novel insights into the fundamental mechanisms governing PCOS.

Role of long non-coding RNAs (lncRNAs) in gastric cancer metastasis: A comprehensive review

One of the greatest frequent types of malignancy is gastric cancer (GC). Metastasis, an essential feature of stomach cancer, results in a high rate of mortality and a poor prognosis. However, metastasis biological procedures are not well recognized. Long non-coding RNAs (lncRNAs) have a role in numerous gene regulation pathways via epigenetic modification as well as transcriptional and post-transcriptional control. LncRNAs have a role in a variety of disorders, such as cardiovascular disease, Alzheimer's, and cancer. LncRNAs are substantially related to GC incidence, progression, metastasis and drug resistance. Several research released information on the molecular processes of lncRNAs in GC pathogenesis. By interacting with a gene's promoter or enhancer region to influence gene expression, lncRNAs can operate as an oncogene or a tumor suppressor. This review includes the lncRNAs associated with metastasis of GC, which may give insights into the processes as well as potential clues for GC predicting and tracking.

miR-135b: An emerging player in cardio-cerebrovascular diseases

miR-135 is a highly conserved miRNA in mammals and includes miR-135a and miR-135b. Recent studies have shown that miR-135b is a key regulatory factor in cardio-cerebrovascular diseases. It is involved in regulating the pathological process of myocardial infarction, myocardial ischemia/reperfusion injury, cardiac hypertrophy, atrial fibrillation, diabetic cardiomyopathy, atherosclerosis, pulmonary hypertension, cerebral ischemia/reperfusion injury, Parkinson's disease, and Alzheimer's disease. Obviously, miR-135b is an emerging player in cardio-cerebrovascular diseases and is expected to be an important target for the treatment of cardio-cerebrovascular diseases. However, the crucial role of miR-135b in cardio-cerebrovascular diseases and its underlying mechanism of action has not been reviewed. Therefore, in this review, we aimed to comprehensively summarize the role of miR-135b and the signaling pathway mediated by miR-135b in cardio-cerebrovascular diseases. Drugs targeting miR-135b for the treatment of diseases and related patents, highlighting the importance of this target and its utility as a therapeutic target for cardio-cerebrovascular diseases, have been discussed.

MicroRNA-135b mainly functions as an oncogene during tumor progression

Late diagnosis is considered one of the main reasons of high mortality rate among cancer patients that results in therapeutic failure and tumor relapse. Therefore, it is needed to evaluate the molecular mechanisms associated with tumor progression to introduce efficient markers for the early tumor detection among cancer patients. The remarkable stability of microRNAs (miRNAs) in body fluids makes them potential candidates to use as the non-invasive tumor biomarkers in cancer screening programs. MiR-135b has key roles in prognosis and survival of cancer patients by either stimulating or inhibiting cell proliferation, invasion, and angiogenesis. Therefore, in the present review we assessed the molecular biology of miR-135b during tumor progression to introduce that as a novel tumor marker in cancer patients. It has been reported that miR-135b mainly acts as an oncogene by regulation of transcription factors, signaling pathways, drug response, cellular metabolism, and autophagy. This review paves the way to suggest miR-135b as a tumor marker and therapeutic target in cancer patients following the further clinical trials and animal studies.

Unveiling the oncogenic role of CLDN11-secreting fibroblasts in gastric cancer peritoneal metastasis through single-cell sequencing and experimental approaches

BACKGROUND

Fibroblasts are necessary to the progression of cancer. However, the role of fibroblasts in peritoneal metastasis (PM) of gastric cancer (GC) remains elusive. In this study, we would explore the role of fibroblasts mediated cell interaction in PM of GC.

METHODS

Single-cell sequencing data from public database GSE183904 was used to explore the specific fibroblast cluster. Fibroblasts were extracted from PM and GC tissues. The expression level of CXCR7 was verified by western blot, immunohistochemistry. The role of CLDN11 was investigate through in vitro and in vivo study. Multiple immunohistochemistry was used to characterize the tumor microenvironment.

RESULTS

CXCR7-positive fibroblasts were significantly enriched in PM of GC. CXCR7 could promote the expression of CLDN11 through activation of the AKT pathway in fibroblasts. Fibroblasts promote the GC proliferation and peritoneal metastasis by secreting CLDN11 in vitro and in vivo. Furthermore, it was revealed that CXCR7-positive fibroblasts were significantly associated with M2-type macrophages infiltration in tissues.

CONCLUSION

CXCR7-positive fibroblasts play an essential role in PM of GC via CLDN11. Therapy targeting CXCR7-positive fibroblasts or CLDN11 may be helpful in the treatment of GC with PM.

EZH2-interacting lncRNAs contribute to gastric tumorigenesis; a review on the mechanisms of action

Gastric cancer (GC) remains one of the deadliest malignancies worldwide, demanding new targets to improve its diagnosis and treatment. Long non-coding RNAs (lncRNAs) are dysregulated through gastric tumorigenesis and play a significant role in GC progression and development. Recent studies have revealed that lncRNAs can interact with histone-modifying polycomb protein, enhance Zeste Homolog 2 (EZH2), and mediate its site-specific functioning. EZH2, which functions as an oncogene in GC, is the catalytic subunit of the PRC2 complex that induces H3K27 trimethylation and epigenetically represses gene expression. EZH2-interacting lncRNAs can recruit EZH2 to the promoter regions of various tumor suppressor genes and cause their transcriptional deactivation via histone methylation. The interactions between EZH2 and this lncRNA modulate different processes, such as cell cycle, cell proliferation and growth, migration, invasion, metastasis, and drug resistance, in vitro and in vivo GC models. Therefore, EZH2-interacting lncRNAs are exciting targets for developing novel targeted therapies for GC. Subsequently, this review aims to focus on the roles of these interactions in GC progression to understand the therapeutic value of EZH2-interacting lncRNAs further.

CCL21 and CLDN11 Are Key Driving Factors of Lymph Node Metastasis in Gastric Cancer

BACKGROUND

Gastric cancer (GC) is a leading cause of cancer-related deaths worldwide. Understanding the molecular mechanisms of GC metastasis is crucial for improving patient survival outcomes.

METHODS

RNA sequencing and analysis were performed on tissue samples from primary and lymph node metastatic lesions of gastric cancer. Differential gene analysis and functional pathway analysis were conducted. Immune infiltrating environment and protein expression levels were evaluated using immunohistochemistry. Cell experiments were conducted to investigate the role of CCL21 in GC metastasis.

RESULTS

ACTG2, CNN1, DES, MUC6, and PGC were significantly upregulated in primary tumor cells, while CCL21, MS4A1, CR2, CLDN11, and FDCSP were significantly upregulated in metastatic tumor cells. Functional pathway analysis revealed enrichment in pathways related to immune response. CLDN11 and CCL21 were found to play important roles in promoting gastric cancer metastasis. Cell experiments confirmed the role of CCL21 in promoting GC cell growth and metastasis. CCL21 is highly expressed in GC tissues and binds to CCR7, leading to upregulation of CLDN11. This results in GC-lymph node metastasis and abnormal activation of immune cells (B cells and CD4+ T cells).

CONCLUSION

Inhibition of CCL21 and CLDN11 proteins may be a promising strategy for treating GC and preventing lymph node metastasis. These findings provide specific molecular markers for early lymph node metastases of GC, which can aid in developing treatment strategies and predicting patient prognosis.

Expression patterns of claudins in cancer

Claudins are four-transmembrane proteins, which were found in tight junctions. They maintain cell barriers and regulate cell differentiation and proliferation. They are involved in maintaining cellular polarity and normal functions. Different claudins show different expression patterns. The expression level and localization of claudins are altered in various cancers. They promote or inhibit proliferation, invasion, and migration of cancer cells through multiple signaling pathways. Therefore, claudins may serve as diagnostic markers, novel therapeutic targets, and prognostic risk factors. The important roles of claudins in cancer aroused our great interest. In the present review, we provide a summary of insights into expression patterns of claudins in cancer, which is more comprehensive and provides new ideas for further research.

α2,6-Sialylation promotes hepatocellular carcinoma cells migration and invasion via enhancement of nSmase2-mediated exosomal miRNA sorting

Exosomes have a critical role in the intercellular communication and metastatic progression of hepatocellular carcinoma (HCC). Recently, our group showed that α2, 6-sialylation played an important role in the proliferation- and migration-promoting effects of cancer-derived exosomes. However, the molecular basis remains elusive. In this study, the mechanism of α2, 6-sialylation-mediated specific microRNAs (miRNA) sorting into exosomes was illustrated. We performed miRNA profiling analysis to compare exosomes from HCC cell lines that differ only in α2, 6-sialylation status. A total of 388 differentially distributed miRNAs were identified in wild-type and β-galactoside α2, 6-sialyltransferase I (ST6Gal-I) knockdown MHCC-97H cells-derived exosomes. Neutral sphingomyelinase-2 (nSmase2), an important regulator mediating the sorting of exosomal miRNAs, was found to be a target of ST6Gal-I. The reduction of α2, 6-sialylation could impair the activity of nSmase2, as well as the nSmase2-dependent exosomal miRNAs sorting. This α2,6-sialylation-dependent sorting exerted an augmentation of motility on recipient HCC cells. Our data further demonstrated that α2,6-sialylation-mediated sorting of exosomal miR-100-5p promoted the migration and invasion of recipient HepG2 cells via the PI3K/AKT signaling pathway. The cellular metastasis-related gene CLDN11 was confirmed as a direct target of exosomal miR-100-5p, which elevated the mobility of recipient HCC cells. In conclusion, our results showed that α2,6-sialylation modulates nSmase2-dependent exosomal miRNAs sorting and promotes HCC progression.

Evaluation of Circ_0000977-Mediated Regulatory Network in Breast Cancer: A Potential Discriminative Biomarker for Triple-Negative Tumors

Previous investigations have revealed that circular RNAs (circRNAs) play pivotal roles in cancer development and progression by participating in several biological procedures, such as competing endogenous RNA (ceRNA) networks. Recently, circRNAs have been proposed as non-invasive, stable, and affordable cell-free biomarkers for cancer screening and test monitoring. Although, their clinical usefulness vastly remains to be evaluated in breast cancer (BC). Triple-negative breast cancer (TNBC), as the most challenging BC subtype, is an urgent requirement of identifying specific biomarkers and discovering the molecular mechanisms that lead to aggressive behaviors of tumor cells. The therapeutic strategies for TN patients have remained limited due to the impracticality of endocrine therapies and a remarkable portion of patients with TNBC experience recurrence, chemoresistance, and metastasis. TNBC Microarray expression profile analysis found that circ_0000977 is one of the most dysregulated circRNA in TNBC in comparison with non-TNBC. It could be a clue referring to the potential clinical utility of circ_0000977 in TNBC. The current study aims to assess the clinical implications and potential ceRNA regulatory network of circ_0000977 in TNBC. We confirmed circ_0000977 down-regulation in TNBC cell lines and tumors versus non-TNBC samples by real-time PCR. Subsequently, an assessment of the diagnostic value of circ_0000977 in plasma samples from triple-negative patients revealed a potential diagnostic cell-free biomarker in triple-negative BC. Finally, our integrative approach uncovered potential circ-0000977/miR-135b-5p/mRNAs regulatory network in TNBC. The inhibitory effect of miR-135b-5p on its downstream mRNAs was assessed by knocking down it in MDA-MB-231 cells. Functional and correlation analyses revealed APC and GATA3 could be regulated by circ_0000977/miR-135b-5p ceRNA axis, which presents valuable insight into circ-0000977-mediated gene silencing involved in the ceRNA network of TNBC. This study uncovered the potential clinical implication of circ_0000977 for the diagnosis and treatment of TNBC patients.

Claudin and pancreatic cancer

Due to the lack of timely and accurate screening modalities and treatments, most pancreatic cancer (PCa) patients undergo fatal PCa progression within a short period since diagnosis. The claudin(CLDN) family is expressed specifically as tight junction structure in a variety of tumors, including PCa, and affects tumor progression by changing the cell junctions. Thus far, many of the 27 members of the claudin family, including claudin-18.2 and claudin-4, have significantly aberrantly expression in pancreatic tumors. In addition, some studies have confirmed the role of some claudin proteins in the diagnosis and treatment of pancreatic tumors. By targeting different targets of claudin protein and combining chemotherapy, further enhance tumor cell necrosis and inhibit tumor invasion and metastasis. Claudins can either promote or inhibit the development of pancreatic cancer, which indicates that the diagnosis and treatment of different kinds of claudins require to consider different biological characteristics. This literature summarizes the functional characteristics and clinical applications of various claudin proteins in Pca cells, with a focus on claudin-18.2 and claudin-4.

Comprehensive analysis of cuproptosis-related long non-coding RNA signature and personalized therapeutic strategy of breast cancer patients

Background

Breast cancer (BC) is considered to be one of the primary causes of cancer deaths in women. Cuproptosis was suggested to play an important role in tumor proliferation and tumor immune microenvironment. Therefore, an investigation was conducted to identify the relationship between cuproptosis-related long non-coding RNAs (lncRNAs) and BC prognosis.

Method

Based on The Cancer Genome Atlas (TCGA), nine cuproptosis-related lncRNAs were identified by Pearson's analysis and Cox regression analysis to create a cuproptosis-related lncRNA signature. Subsequently, patients with BC were divided into high-risk and low-risk groups. The Kaplan-Meier curves and a time-dependent receiver operating characteristic (ROC) analysis were employed to elucidate the predictive capability of the signature. After that, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted by Gene Set Enrichment Analysis (GSEA), and the lncRNA-mRNA co-expression network was established by Cytoscape software. Furthermore, the ESTIMATE score was calculated, and the immune cell type component analysis was conducted. Eventually, immunotherapy response analysis was applied to identify the predictive power of cuproptosis-related lncRNAs to tumor immunotherapy response, including immune checkpoint gene expression levels, tumor mutational burden (TMB), and microsatellite instability (MSI).

Results

Patients with BC in the low-risk groups showed better clinical outcomes. The KEGG pathways in the high-risk groups were mainly enriched in immune response and immune cell activation. Furthermore, the ESTIMATE scores were higher in the low-risk groups, and their immune cell infiltrations were dramatically different from those of the high-risk groups. The low-risk groups were shown to have higher infiltration levels of CD8+ T cells and TMB-high status, resulting in better response to immunotherapies.

Conclusion

The findings of this study revealed that the nine-cuproptosis-related lncRNA risk score was an independent prognostic factor for BC. This signature was a potential predictor for BC immunotherapy response. What we found will provide novel insight into immunotherapeutic treatment strategies in BC.

N1-Methyladenosine-Related lncRNAs Are Potential Biomarkers for Predicting Prognosis and Immune Response in Uterine Corpus Endometrial Carcinoma

Uterine corpus endometrial carcinoma (UCEC) is a malignant disease that, at present, has no well-characterised prognostic biomarker. In this study, two clusters were identified based on 28 N1-methyladenosine- (m1A-) related long noncoding RNAs (lncRNAs), of which cluster 1 was related to immune pathways according to the results of an enrichment analysis. We further observed better prognosis in patients with higher levels of immune cell infiltration, tumor mutation burden, microsatellite instability, and immune checkpoint gene expression. In addition, through Cox regression analysis and least absolute shrinkage and selection operator regression analysis, 10 m1A-related lncRNAs (mRLs) were employed to build a prognosis model. We found that people in higher risk categories had a poorer survival probability than those in lower risk. Low-risk samples were enriched with immune-related pathways, while the high-risk group was similar to the definition of the “immune desert” phenotype, which was associated with decreased immune infiltration, T cell failure, and decreased tumor mutation burden, while also being insensitive to immunotherapy and chemotherapy. This mRL-based model has the ability to accurately predict the prognosis of UCEC patients, and the mRLs could become promising therapeutic targets in enhancing the response of immunotherapy.

Pyroptosis-related lncRNAs are potential biomarkers for predicting prognoses and immune responses in patients with UCEC

Uterine corpus endometrial carcinoma (UCEC) is a malignant disease globally, and there is no unified prognostic signature at present. In our study, two clusters were identified. Cluster 1 showed better prognosis and higher infiltration level, such as tumor microenvironment (TME), tumor mutation burden (TMB), and immune checkpoint genes expression. Gene set enrichment analysis (GSEA) indicated that some tumor-related pathways and immune-associated pathways were exposed. What is more, six pyroptosis-related long noncoding RNAs (lncRNAs) (PRLs) were applied to establish a prognostic signature through multiple Cox regression analysis. In both training and testing sets, patients with higher risk score had poorer survival than patients with low risk. The area under the curve (AUC) of receiver operating characteristic (ROC) curves performed that the survival probability was better in people with lower risk score. Mechanism analysis revealed that high risk score was correlated with reduced immune infiltration and T cells exhaustion, matching the definition of an "immune-desert" phenotype. Patients with lower risk score were characterized by higher immune checkpoint gene expression and TMB and have a sensitive response to immunotherapy and chemotherapy compared with patients with high risk score. The signature has accurate prediction ability of UCEC and is a promising therapeutic target to improve the effect of immunotherapy.

Gastric cancer-derived exosomal miR-135b-5p impairs the function of Vγ9Vδ2 T cells by targeting specificity protein 1

Recent studies have shown that tumor-derived exosomes participate in the communication between tumor cells and their microenvironment and mediate malignant biological behaviors including immune escape. In this study, we found that gastric cancer (GC) cell-derived exosomes could be effectively uptaken by Vγ9Vδ2 T cells, decrease the cell viability of Vγ9Vδ2 T cells, induce apoptosis, and reduce the production of cytotoxic cytokines IFN-γ and TNF-α. Furthermore, we demonstrated that exosomal miR-135b-5p was delivered into Vγ9Vδ2 T cells. Exosomal miR-135b-5p impaired the function of Vγ9Vδ2 T cells by targeting specificity protein 1 (SP1). More importantly, blocking the SP1 function by Plicamycin, an SP1 inhibitor, abolished the effect of stable miR-135b-5p knockdown GC cell-derived exosomes on Vγ9Vδ2 T cell function. Collectively, our results suggest that GC cell-derived exosomes impair the function of Vγ9Vδ2 T cells via miR-135b-5p/SP1 pathway, and targeting exosomal miR-135b-5p/SP1 axis may improve the efficiency of GC immunotherapy based on Vγ9Vδ2 T cells.

Therapeutic Response-Based Reclassification of Multiple Tumor Subtypes Reveals Intrinsic Molecular Concordance of Therapy Across Histologically Disparate Cancers

Cancers that are histologically defined as the same type of cancer often need a distinct therapy based on underlying heterogeneity; likewise, histologically disparate cancers can require similar treatment approaches due to intrinsic similarities. A comprehensive analysis integrated with drug response data and molecular alterations, particularly to reveal therapeutic concordance mechanisms across histologically disparate tumor subtypes, has not yet been fully exploited. In this study, we integrated pharmacological, genomic, and transcriptomic profiling data provided from the Cancer Genome Project (CGP) in a systematic in silico investigation of the pharmacological subtypes of cancers and the intrinsic concordance of molecular mechanisms leading to similar therapeutic responses across histologically disparate tumor subtypes. We further developed a novel approach to redefine cell-to-cell similarity and drug-to-drug similarity from the therapeutic concordance, providing a new point of view to study cancer heterogeneity. This study demonstrates how pharmacological and omics data can be used to systematically classify cancers in terms of response to various compounds and provides us with a purely therapy-oriented perspective to view tumor classifications independent of histology subtypes. The knowledge of pharmacological subtypes of 367 drugs are available via our website (http://www.hywanglab.cn/dtdb/), providing the resources for precision medicine in the perspective of therapeutic response-based re-classification of tumor.

Dysregulated expression of claudins in cancer

Claudins are adhesion molecules located at the tight junctions between epithelial cells. A series of studies have now reported aberrant expression of claudin proteins in the context of neoplastic transformation, suggesting its role in tumorigenesis. However, the precise mechanisms are still not well understood. Studies on expression alterations of claudins have revealed a range of outcomes that reflect the complexity of claudins in terms of spatial localization, tumor type and stage of disease. The diverse and dynamic expression patterns of claudins in cancer are tightly controlled by a wide range of regulatory mechanisms, which are commonly modulated by oncogenic signaling pathways. The present review summarizes the recent knowledge describing the dysregulation of claudin expression in cancer and discusses the intrinsic and extrinsic determinants of the context-specific expression patterns of claudins.

m5C-Related lncRNAs Predict Overall Survival of Patients and Regulate the Tumor Immune Microenvironment in Lung Adenocarcinoma

Long non-coding RNAs (lncRNAs), which are involved in the regulation of RNA methylation, can be used to evaluate tumor prognosis. lncRNAs are closely related to the prognosis of patients with lung adenocarcinoma (LUAD); thus, it is crucial to identify RNA methylation-associated lncRNAs with definitive prognostic value. We used Pearson correlation analysis to construct a 5-Methylcytosine (m5C)-related lncRNAs–mRNAs coexpression network. Univariate and multivariate Cox proportional risk analyses were then used to determine a risk model for m5C-associated lncRNAs with prognostic value. The risk model was verified using Kaplan–Meier analysis, univariate and multivariate Cox regression analysis, and receiver operating characteristic curve analysis. We used principal component analysis and gene set enrichment analysis functional annotation to analyze the risk model. We also verified the expression level of m5C-related lncRNAs in vitro. The association between the risk model and tumor-infiltrating immune cells was assessed using the CIBERSORT tool and the TIMER database. Based on these analyses, a total of 14 m5C-related lncRNAs with prognostic value were selected to build the risk model. Patients were divided into high- and low-risk groups according to the median risk score. The prognosis of the high-risk group was worse than that of the low-risk group, suggesting the good sensitivity and specificity of the constructed risk model. In addition, 5 types of immune cells were significantly different in the high-and low-risk groups, and 6 types of immune cells were negatively correlated with the risk score. These results suggested that the risk model based on 14 m5C-related lncRNAs with prognostic value might be a promising prognostic tool for LUAD and might facilitate the management of patients with LUAD.

LncRNA PCAT18 Promotes Non-Small Cell Lung Cancer Progression by Sponging miR-4319

Introduction

NSCLC (non-small cell lung cancer), the most common type of human cancer, is a main cause of cancer-associated mortality. Accumulating evidence has confirmed that long non-coding RNAs serve crucial roles in NSCLC development.

Methods

The PCAT18 expression in NSCLC tissues and cell lines were evaluated by reverse transcription-quantitative PCR. Cell Counting Kit-8 assays, colony formation study, wound healing assays and transwell invasion assays, and tumor xenograft experiments were performed to investigate the biological functions of PCAT18 in NSCLC. Luciferase reporter, RNA-binding protein immunoprecipitation (RIP) and RNA pull-down assays were further used to explore the association between PCAT18 and miR-4319.

Results

PCAT18 expression was up-regulated in NSCLC tissues and cell lines. Furthermore, PCAT18 silencing inhibited NSCLC cell proliferation, migration and invasion, while co-transfection with a miR-4319 inhibitor reversed these biological effects, and miR-4319 inhibited NSCLC growth in vivo. Additionally, PCAT18 silencing promoted NSCLC cell apoptosis and induced G1 stage arrest. Moreover, luciferase reporter assays illustrated that PCAT18 regulated miR-4319 directly, and a RIP assay and RNA pull-down analysis further demonstrated that miR-4319 inhibited PCAT18 in a RNA-induced silencing complex-dependent manner. Finally, PCAT18 silencing impaired the growth of NSCLC in vivo.

Conclusion

In conclusion, these findings demonstrated that PCAT18 promoted NSCLC development by sponging miR-4319. PCAT18 may serve as a crucial biomarker for the diagnosis and targeted therapy of NSCLC.

Long Noncoding RNA PCAT18 Upregulates SPRR3 to Promote Colorectal Cancer Progression by Binding to miR-759

Background

Long noncoding RNAs (lncRNAs) play essential functions in the development of several cancers, including colorectal cancer (CRC). Nevertheless, how PCAT18 regulates CRC tumorigenesis remains unclear. In this research, we aimed to investigate the roles of PCAT18 in CRC.

Materials and Methods

qRT-PCR and Western blot were used to analyze RNA and protein levels. CCK8, colony formation, transwell and wound healing assays were utilized to analyze proliferation, migration and invasion. Luciferase reporter assay was used to analyze RNA interactions.

Results

PCAT18 was found to be highly expressed in CRC tissues and cells. PCAT18 level was positively correlated with lymph node metastasis and TNM stage. Functionally, PCAT18 silencing induced impairment of CRC proliferation, migration and invasion. Besides, PCAT18 was identified to inhibit miR-759. PCAT18 promotes SPRR3 expression through binding to miR-759. Furthermore, miR-759 inhibitors or SPRR3 ectopic expression partially rescued the abilities of proliferation, migration and invasion in CRC cells transfected with sh-PCAT18.

Conclusion

Therefore, our study demonstrated that PCAT18 contributes to CRC progression through regulating miR-759/SPRR3 axis, which provides a new theoretical basis of explaining CRC tumorigenesis.

LINC00689 induces gastric cancer progression via modulating the miR-338-3p/HOXA3 axis

BACKGROUND

LINC00689 acts one critical regulatory role in several tumors. However, the functional, regulatory mechanism and expression of LINC00689 remains unknown in gastric cancer.

METHODS

LINC00689 and miR-338-3p levels were determined using a quantitative reverse transcriptase-polymerase chain reaction analysis and an enzyme-linked immunoassay and a cell-counting kit-8 assay were utilized to detect interleukin (IL)-8, IL-6 and IL-1β expression and cell proliferation, respectively.

RESULTS

We found that LINC00689 and HOXA3 are overexpressed and miR-338-3p is decreased in gastric cancer cells. Compared to control specimens, LINC00689 is overexpressed in gastric cancer specimens and the level of LINC00689 was up-regulated in 32 cases (32/40; 80.0%) compared to control samples. LINC00689 increased cell growth, epithelial-mesenchymal transition (EMT) development and secretion of inflammatory factors in gastric cancer. Compared to control specimens, miR-338-3p expression was decreased in gastric cancer specimens and a Pearson's correlation assay revealed that miR-338-3p was negatively correlated with LINC00689 expression in gastric cancer specimens. HOXA3 was identified as one target gene of miR-338-3p and Ectopic expression of LINC00689 suppressed miR-338-3p and enhanced HOXA3 expression in HGC-27 cells. LINC00689 enhanced cell growth, EMT development and secretion of inflammatory factors by promoting HOXA3.

CONCLUSIONS

LINC00689 may present a potential future target for gastric cancer treatment.