Long non-coding RNA CASC19 is associated with the progression and prognosis of advanced gastric cancer

Genome-wide investigation of lncRNAs revealed their tight association with gastric cancer

BACKGROUND

Gastric cancer (GC) is a significant health issue globally, ranking as the fifth most common cancer with over 10,000 new cases reported annually. Long non-coding RNA (lncRNA) has emerged as a critical player in cellular functions, influencing GC's development, growth, metastasis, and prognosis. However, our understanding of lncRNA's role in the pathogenesis of GC remains limited. Therefore, it is particularly important to explore the relationship between lncRNA and gastric cancer.

METHODS

we conducted a comprehensive analysis of RNA sequencing data from the GEO database and stomach adenocarcinoma (STAD) data from the TCGA database to identify lncRNAs that exhibit altered expression levels in GC and the mechanisms underlying lncRNA-mediated transcription and post-transcriptional regulation were explored.

RESULTS

This study uncovered 94 lncRNAs with differential expression and, through co-expression analysis, linked these to 1508 differentially expressed genes (DEGs). GO functional enrichment analysis highlighted that these DEGs are involved in critical pathways, such as cell adhesion and the positive regulation of cell migration. By establishing a lncRNA-miRNA-mRNA regulatory network, we found that the ceRNA mechanism, particularly involving RP11-357H14.17 and CTD-2377D24.4, could play a role in GC progression. Experimental validation of selected differentially expressed lncRNAs and mRNAs (including RP11-357H14.17-CLDN1, BBOX1, TRPM2-AS, CLDN1, PLAU, HOXB7) confirmed the RNA-seq results.

CONCLUSIONS

Overall, our findings highlight the critical role of the lncRNA-mRNA regulatory network in the development and progression of GC, offering potential biomarkers for diagnosis and targets for innovative treatment strategies.

CASC19: An Oncogenic Long Non-coding RNA in Different Cancers

A 324 bp lncRNA called CASC19 is found on chromosome 8q24.21. Recent research works have revealed that CASC19 is involved in the prognosis of tumors and related to the regulation of the radiation tolerance mechanisms during tumor radiotherapy (RT). This review sheds light on the changes and roles that CASC19 plays in many tumors and diseases, such as nasopharyngeal carcinoma (NPC), cervical cancer, colorectal cancer (CRC), non-small cell lung cancer (NSCLC), clear cell renal cell carcinoma (ccRCC), gastric cancer (GC), pancreatic cancer (PC), hepatocellular carcinoma (HCC), glioma, and osteoarthritis (OA). CASC19 provides a new strategy for targeted therapy, and the regulatory networks of CASC19 expression levels play a key role in the occurrence and development of tumors and diseases. In addition, the expression level of CASC19 has predictive roles in the prognosis of some tumors and diseases, which has major implications for clinical diagnoses and treatments. CASC19 is also unique in that it is a key gene affecting the efficacy of RT in many tumors, and its expression level plays a decisive role in improving the success rate of treatments. Further research is required to determine the precise process by which CASC19 causes changes in diseased cells in some tumors and diseases.

Development of a well-defined tool to predict the overall survival in lung cancer patients: an African based cohort

BACKGROUND

Nomogram is a graphic representation containing the expressed factor of the mathematical formula used to define a particular phenomenon. We aim to build and internally validate a nomogram to predict overall survival (OS) in patients diagnosed with lung cancer (LC).

METHODS

We included 1200 LC patients from a single institution registry diagnosed from 2013 to 2021. The independent prognostic factors of LC patients were identified via cox proportional hazard regression analysis. Based on the results of multivariate cox analysis, we constructed the nomogram to predict the OS of LC patients.

RESULTS

We finally included a total of 1104 LC patients. Age, medical urgency at diagnosis, performance status, radiotherapy, and surgery were identified as prognostic factors, and integrated to build the nomogram. The model performance in predicting prognosis was measured by receiver operating characteristic curve. Calibration plots of 6-, 12-, and 24- months OS showed optimal agreement between observations and model predictions.

CONCLUSION

We have developed and validated a unique predictive tool that can offer patients with LC an individual OS prognosis. This useful prognostic model could aid doctors in making decisions and planning therapeutic trials.

LncRNA CASC19: a novel oncogene involved in human cancer

Multiple studies have shown that long non-coding RNAs (lncRNAs) play an important role in the occurrence and development of diverse cancers. Cancer susceptibility candidate 19 (CASC19), encoded by chromosome 8q24.21, is a newly discovered lncRNA that contains 324 nucleotides. CASC19 has been found to be significantly overexpressed in different human cancers, such as non-small cell lung carcinoma, gastric cancer, colorectal cancer, pancreatic cancer, clear cell renal cell carcinoma, glioma, cervical cancer, and nasopharyngeal carcinoma. Moreover, dysregulation of CASC19 was closely associated with clinicopathological parameters and cancer progression. CASC19 regulates a variety of cell phenotypes, including cell proliferation, apoptosis, cell cycle, migration, invasion, epithelial-mesenchymal transition, autophagy, and therapeutic resistance. In this study, we review recent studies on the characteristics and biological function of CASC19, as well as its role in human cancers. These findings suggest that CASC19 may be both a reliable biomarker and a potential therapeutic target in cancers.

Identification and validation of a m7G-related lncRNA signature for predicting the prognosis and therapy response in hepatocellular carcinoma

BACKGROUND

N7-methylguanosine (m7G) is one of the most common RNA posttranscriptional modifications; however, its potential role in hepatocellular carcinoma (HCC) remains unknown. We developed a prediction signature based on m7G-related long noncoding RNAs (lncRNAs) to predict HCC prognosis and provide a reference for immunotherapy and chemotherapy.

METHODS

RNA-seq data from The Cancer Genome Atlas (TCGA) database and relevant clinical data were used. Univariate and multivariate Cox regression analyses were conducted to identify m7G-related lncRNAs with prognostic value to build a predictive signature. We evaluated the prognostic value and clinical relevance of this signature and explored the correlation between the predictive signature and the chemotherapy treatment response of HCC. Moreover, an in vitro study to validate the function of CASC19 was performed.

RESULTS

Six m7G-related lncRNAs were identified to create a signature. This signature was considered an independent risk factor for the prognosis of patients with HCC. TIDE analyses showed that the high-risk group might be more sensitive to immunotherapy. ssGSEA indicated that the predictive signature was strongly related to the immune activities of HCC. HCC in high-risk patients was more sensitive to the common chemotherapy drugs bleomycin, doxorubicin, gemcitabine, and lenalidomide. In vitro knockdown of CASC19 inhibited the proliferation, migration and invasion of HCC cells.

CONCLUSION

We established a 6 m7G-related lncRNA signature that may assist in predicting the prognosis and response to chemotherapy and immunotherapy of HCC.

m6A-related lncRNAs predict prognosis and indicate cell cycle in gastric cancer

Background: N6-methyladenosine (m6A) modification is a common epigenetic methylation modification of RNA, which plays an important role in gastric carcinogenesis and progression by regulating long non-coding RNA (lncRNA). This study is aimed to investigate the potential prognostic signatures of m6A -related lncRNAs in STAD. Methods: The m6A-related lncRNAs with the most significant impact on gastric cancer prognosis in the TCGA database were identified by bioinformatics and machine learning methods. The m6A-related lncRNA prognostic model (m6A-LPS) and nomogram was constructed by Cox regression analysis with the minimum absolute contraction and selection operator (LASSO) algorithm. The functional enrichment analysis of m6A-related lncRNAs was also investigated. The miRTarBase, miRDB and TargetScan databases were utilized to establish a prognosis-related network of competing endogenous RNA (ceRNA) by bioinformatics methods. The correlation of AL391152.1 expressions and cell cycle were experimentally testified by qRT-PCR and flow cytometry. Results: In total, 697 lncRNAs that were identified as m6A-related lncRNAs in GC samples. The survival analysis showed that 18 lncRNAs demonstrated prognostic values. A risk model with 11 lncRNAs was established by Lasso Cox regression, and can predict the prognosis of GC patients. Cox regression analysis and ROC curve indicated that this lncRNA prediction model was an independent risk factor for survival rates. Functional enrichment analysis and ceRNA network revealed that the nomogram was notably associated with cell cycle. qRT-PCR and flow cytometry revealed that downregulation of GC m6A-related lncRNA AL391152.1 could decrease cyclins expression in SGC7901 cells. Conclusion: A m6A-related lncRNAs prognostic model was established in this study, which can be applied to predict prognosis and cell cycle in gastric cancer.

Molecular regulation of hypoxia through the lenses of noncoding RNAs and epitranscriptome

Cells maintain homeostasis in response to environmental stress through specific cell stress responses. Hypoxic stress, well known to be associated with diverse solid tumors, is one of the main reasons for cancer-related mortality. Although cells can balance themselves well during hypoxic stress, the underlying molecular mechanisms are not well understood. The enhanced appreciation of diverse roles played by noncoding transcriptome and epigenome in recent years has brought to light the involvement of noncoding RNAs and epigenetic modifiers in hypoxic regulation. The emergence of techniques like deep sequencing has facilitated the identification of large numbers of long noncoding RNAs (lncRNAs) that are differentially regulated in various cancers. Similarly, proteomic studies have identified diverse epigenetic modifiers such as HATs, HDACs, DNMTs, polycomb groups of proteins, and their possible roles in the regulation of hypoxia. The crosstalk between lncRNAs and epigenetic modifiers play a pivotal role in hypoxia-induced cancer initiation and progression. Besides the lncRNAs, several other noncoding RNAs like circular RNAs, miRNAs, and so forth are also expressed during hypoxic conditions. Hypoxia has a profound effect on the expression of noncoding RNAs and epigenetic modifiers. Conversely, noncoding RNAs/epigenetic modifies can regulate the hypoxia signaling axis by modulating the stability of the hypoxia-inducible factors (HIFs). The focus of this review is to illustrate the molecular orchestration underlying hypoxia biology, especially in cancers, which can help in identifying promising therapeutic targets in hypoxia-induced cancers. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA in Disease and Development > RNA in Disease RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.

Overexpression of CASC19 contributes to tumor progression and predicts poor prognosis after radical resection in hepatocellular carcinoma

BACKGROUND

Long non-coding RNAs (lncRNAs) have been implicated as functional molecules in hepatocellular carcinoma (HCC) progression. The present research aimed to investigate the levels of LncRNA cancer susceptibility candidate gene 19 (CASC19) in HCC tissues and cell lines and to explore its potential role in the diagnosis and prognosis of HCC.

METHODS

HCC tissues and cell lines were collected to assess the levels of CASC19 by real-time quantitative reverse transcription PCR (RT-qPCR). The prognostic value of CASC19 was evaluated using the Kaplan-Meier method and Cox regression analysis. The functional role of CASC19 in regulating HCC cell proliferation, migration, and invasion was evaluated by Cell Counting Kit-8 (CCK-8) and Transwell analysis. The potential targeted miR-140-5p of CASC19 was confirmed by a dual-luciferase reporter assay.

RESULTS

High CASC19 expression positively correlated with tumor size, differentiation, and TNM stage in HCC patients (P < 0.05). Patients with high CASC19 expression have a poorer survival prognosis and are prone to relapse compared to those with low CASC19. miR-140-5p, a target miRNA for CASC19, negatively correlated with CASC19 levels in tumor tissues. Reduced CASC19 levels attenuated cell proliferation, migration, and invasion, but this attenuation was reversed by suppression of miR-140-5p.

CONCLUSION

Up-regulated CASC19 may serve as a biomarker for predicting poor prognosis in HCC patients. In vitro, overexpressed CASC19 promoted the progression of HCC, indicating that CASC19 may be a possible therapeutic target for the treatment of HCC.

Prognostic and Predictive Model of the Log Odds of the Negative Lymph Node/T Stage Ratio in Resectable Gastric Adenocarcinoma Patients

PURPOSE

There are few reports on disease-specific survival (DSS) prediction systems for resected gastric cancer (GC) patients. The aim of this study was to create a nomogram based on the log odds of the negative lymph node/T stage ratio (LONT) for individual risk prediction.

METHODS

We applied the Surveillance, Epidemiology, and End Results (SEER) Program database released in 2021 to screen GC patients from 2010 to 2015. Using a competitive risk model, we plotted the cumulative risk curve of variables for gastric cancer-specific death and death from other causes at each time point. According to the minimum BIC, we constructed and assessed a nomogram for the 12-month, 36-month, and 60-month cumulative mortality probabilities assessed by time-dependent ROC curves (time-AUCs), the C-index, Brier scores, decision curve analysis (DCA), and calibration curves.

RESULTS

A total of 3895 patients were ultimately included and randomly assigned to two sets: the training set (n = 2726, 70%) and the validation set (n = 1169, 30%). The LONT was a remarkable independent predictor of gastric cancer-specific death (high versus low: 0.705, 95% CI 0.524-0.95, p = 0.021). The variables selected based on the minimum BIC were as follows: location, AJCC, AJCC.T, AJCC.N, radiotherapy, LONT.cat, and chemotherapy. According to the time-AUC, C-index, Brier score, DCA, and calibration curves, the nomogram risk score had excellent survival prediction ability for DSS.

CONCLUSIONS

A low LONT was associated with a high cumulative incidence of DSS. A prognostic nomogram model based on the LONT could effectively predict DSS for resectable GC patients.

Identification of an Epithelial-Mesenchymal Transition-Related Long Non-coding RNA Prognostic Signature to Determine the Prognosis and Drug Treatment of Hepatocellular Carcinoma Patients

Introduction

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with poor prognosis. Epithelial–mesenchymal transition (EMT) is crucial for cancer progression and metastasis. Thus, we aimed to construct an EMT-related lncRNA signature for predicting the prognosis of HCC patients.

Methods

Cox regression analysis and LASSO regression method were used to build an EMT-related lncRNAs risk signature based on TCGA database. Kaplan-Meier survival analysis was conducted to compare the overall survival (OS) in different risk groups. ROC curves and Cox proportional-hazards analysis were performed to evaluate the performance of the risk signature. RT-qPCR was conducted in HCC cell lines and tissue samples to detect the expression of some lncRNAs in this risk model. Furthermore, a nomogram involving the risk score and clinicopathological features was built and validated with calibration curves and ROC curves. In addition, we explored the association between risk signature and tumor immunity, somatic mutations status, and drugs sensitivity.

Results

Twelve EMT-related lncRNAs were obtained to construct the prognostic risk signature for patients with HCC. The Kaplan-Meier curve analysis revealed that patients in the high-risk group had worse overall survival (OS) than those in low-risk group. ROC curves and Cox regression analysis suggested the risk signature could predict HCC survival exactly and independently. The prognostic value of the risk model was confirmed in the testing and entire groups. We also found AC099850.3 and AC092171.2 were highly expressed in HCC cells and HCC tissues. The nomogram could accurately predict survival probability of HCC patients. Gene set enrichment analysis (GSEA) and gene ontology (GO) analysis showed that cancer-related pathways and cell division activity were enriched in high-risk group. The SNPs showed that the prevalence of TP53 mutations was significantly different between high- and low-risk groups; the TP53 mutations and the high TMB were both associated with a worse prognosis in patients with HCC. We also observed widely associations between risk signature and drugs sensitivity in HCC.

Conclusion

A novel EMT-related lncRNAs risk signature, including 12 lncRNAs, was established and identified in patients with HCC, which can accurately predict the prognosis of HCC patients and may be used to guide individualized treatment in the clinical practice.

Role of long non-coding RNA in regulating polarization of gastric cancer macrophages

Tumor-associated macrophages (TAMs) are an important part of the tumor microenvironment. They are distributed in tumor tissues and distant metastatic sites, and are related to tumor progression and prognosis. TAMs M2 can promote tumor biological processes such as tumor proliferation, invasion, and metastasis, and inhibit apoptosis, and are obviously related to the poor prognosis of tumor patients. In recent years, the role of long non-coding RNAs (lncRNAs) in regulating the polarization of macrophages has gradually been revealed, which can affect the occurrence and development of tumors by adjusting the polarization of macrophages. Studies have shown that lncRNAs play an important role in the polarization process of gastric cancer macrophages. This article summarizes the related research reports, hoping to provide ideas for studies that interfere with the polarization process of TAMs to inhibit tumor progression.

Weighted gene co-expression network analysis of the association between upregulated AMD1, EN1 and VGLL1 and the progression and poor prognosis of breast cancer

Breast cancer is the most prevalent malignancy among females, but the molecular mechanisms involved in its pathogenesis and progression have remained to be fully elucidated. The aim of the present study was to identify novel potential therapeutic targets for breast cancer. The dataset GSE76275 was downloaded from the Gene Expression Omnibus database and weighted gene co-expression network analysis (WGCNA) was performed to identify hub genes. Furthermore, the dataset GSE25055, containing gene expression data and clinical information, was downloaded to validate the expression and survival association of these hub genes. In addition, the datasets GSE25065 and GSE42568 were used to validate the association between hub gene expression levels and clinical features. Immunohistochemistry (IHC), reverse transcription-quantitative PCR, as well as proliferation, migration, invasion and apoptosis assays, were used to verify gene expression and function. A total of 4,052 genes were selected for WGCNA and 18 modules were established; the red module was identified as the key module, as it had a strong positive correlation with the tumor grade. Survival analyses of hub genes [S-adenosylmethionine decarboxylase proenzyme (AMD1), homeobox protein engrailed-1 (EN1) and vestigial-like protein (VGLL1)] indicated that higher levels of gene expression were associated with poor prognosis of patients with breast cancer. This association was based on survival analysis of GSE25055 using the Kaplan-Meier plotter tool. Expression validation revealed that the upregulation of hub genes was associated with advanced tumor grade and malignant molecular subtype (basal-like). IHC results from the Human Protein Atlas also demonstrated that protein expression levels of the hub genes were higher in tumor tissues compared with those in adjacent normal tissues. Furthermore, the expression levels of AMD1, EN1 and VGLL1 were strongly correlated with each other. These results demonstrated that AMD1 is highly expressed in breast cancer tissues and cells and AMD1 knockdown decreased the proliferation and metastatic potential, while increasing apoptosis of breast cancer cells. These results suggested that AMD1, EN1 and VGLL1 are likely to contribute to breast cancer progression and unfavorable prognosis.

The log odds of negative lymph nodes/T stage: a new prognostic and predictive tool for resected gastric cancer patients

Purpose

When only the TNM classification is used to predict survival in gastric cancer (GC) patients, the impact of the degree of lymphadenectomy on the prognosis is neglected. This study aimed to establish a more effective nomogram based on the log odds of negative lymph nodes/T stage ratio (LONT) to predict survival in surgically treated GC patients.

Methods

The data of resected GC patients were extracted from the Surveillance, Epidemiology, and End Results Program (SEER) database. Univariate and multivariate Cox regression analyses were used to identify the significant prognostic factors. The prognostic performance was assessed using a calibration plot, concordance index (C-index), and area under the (time-dependent receiver operating characteristic) curve (AUC) to compare the predicted survival probability based on the nomogram score groups.

Results

The results showed LONT as an independent prognostic factor for cancer-specific survival (CSS) and overall survival (OS), independent of clinicopathological factors. After removing potential redundancy, only LONT, T stage, N stage, location and age were used in the final nomogram model. The model had a higher C-index (0.736 ± 0.012) and AUC (0.798) than the TNM staging system (0.685 ± 0.012 and 0.744). The nomogram score could predict a significant survival difference between any two adjacent groups in terms of CSS and OS.

Conclusion

High LONT is associated with improved survival of gastric cancer patients, independent of other clinicopathological factors. The prognostic nomogram model based on LONT could effectively predict CSS and OS for resectable GC patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03654-y.

Function of Non-coding RNA in Helicobacter pylori-Infected Gastric Cancer

Gastric cancer is a common malignant tumor of the digestive system. Its occurrence and development are the result of a combination of genetic, environmental, and microbial factors. Helicobacter pylori infection is a chronic infection that is closely related to the occurrence of gastric tumorigenesis. Non-coding RNA has been demonstrated to play a very important role in the organism, exerting a prominent role in the carcinogenesis, proliferation, apoptosis, invasion, metastasis, and chemoresistance of tumor progression. H. pylori infection affects the expression of non-coding RNA at multiple levels such as genetic polymorphisms and signaling pathways, thereby promoting or inhibiting tumor progression or chemoresistance. This paper mainly introduces the relationship between H. pylori-infected gastric cancer and non-coding RNA, providing a new perspective for gastric cancer treatment.

Construction of Competitive Endogenous RNA Network and Verification of 3-Key LncRNA Signature Associated With Distant Metastasis and Poor Prognosis in Patients With Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common malignancy with high distant metastasis rate. Long non-coding RNAs (LncRNAs) are reported to be upregulated or downregulated in multiple cancers and play a crucial role in the metastasis of tumors or prognosis. Therefore, the purpose of our study is to construct a prognostic signature for ccRCC based on distant metastasis-related lncRNAs and explore the involved potential competitive endogenous RNA (ceRNA) network. The differentially expressed genes (DEGs) screened from the database of the cancer genome atlas (TCGA) were used to construct a co-expression network and identify the distant metastasis-related module by weighted gene co-expression network analysis (WGCNA). Key genes with metastatic and prognostic significance were identified through rigorous screening, including survival analysis, correlation analysis, and expression analyses in stage, grade, and distant metastasis, and were verified in the data set of gene expression omnibus (GEO) and the database from gene expression profiling interactive analysis (GEPIA). The potential upstream miRNAs and lncRNAs were predicted via five online databases and LncBase. Here, we constructed a ceRNA network of key genes that are significantly associated with the distant metastasis and prognosis of patients with ccRCC. The distant metastasis-related lncRNAs were used to construct a risk score model through the univariate, least absolute shrinkage selection operator (LASSO), and multivariate Cox regression analyses, and the patients were divided into high- and low-risk groups according to the median of the risk score. The Kaplan–Meier survival analysis demonstrated that mortality was significantly higher in the high-risk group than in the low-risk group. Considering the other clinical phenotype, the Cox regression analyses indicated that the lncRNAs model could function as an independent prognostic factor. Quantitative real-time (qRT)-PCR in the tissues and cells of ccRCC verified the high-expression level of three lncRNAs. Gene set enrichment analysis (GSEA) revealed that the lncRNA prognostic signature was mainly enriched in autophagy- and immune-related pathways, indicating that the autophagy and immune functions may play an important role in the distant metastasis of ccRCC. In summary, the constructed distant metastasis-related lncRNA signature could independently predict prognosis in patients with ccRCC, and the related ceRNA network provided a new sight on the potential mechanism of distant metastasis and a promising therapeutic target for ccRCC.

Long non-coding RNA HAND2-AS1 inhibits gastric cancer progression by suppressing TCEAL7 expression via targeting miR-769-5p

Increasing evidence showed that Heart and Neural Crest Derivatives Expressed 2 antisense RNA 1 (HAND2-AS1) was involved in the progression of several cancers, but its expression and function in gastric cancer (GC) was rarely reported. HAND2-AS1 expression in GC tissues and cells was detected at first. Cell function assays were performed to investigate the biological roles of HAND2-AS1 in GC cells. Moreover, the genes regulated by HAND2-AS1 in GC were investigated. Downregulation of HAND2-AS1 was found in GC tissues and cell lines. HAND2-AS1 overexpression inhibited GC cell proliferation, invasion, and arrested cell cycle at G0/G1 phase, whereas HADN2-AS1 knockdown significantly promoted cell proliferation and invasion. Bioinformatic analysis showed there is a potential HADN2-AS1/microRNA-769-5p (miR-769-5p)/transcription elongation factor A like 7 (TCEAL7) axis in GC. Luciferase activity reporter system was used to confirm this link. Taken together, our study showed that HAND2-AS1 exerts its tumor suppressive role in GC via regulating miR-769-5p/TCEAL7.

Knockdown of TPT1-AS1 inhibits cell proliferation, cell cycle G1/S transition, and epithelial-mesenchymal transition in gastric cancer

Long non-coding RNAs are considered to be critical regulators of tumor progression. Tumor protein translationally controlled 1 antisense RNA 1 (TPT1-AS1) was shown to have an oncogenic role in cervical and ovarian cancer. The clinical significance and biological function of TPT1-AS1 in gastric cancer (GC) are not clear. In this study, we analyzed the expression of TPT1-AS1 in GC tissues and cell lines and performed functional and mechanistic analysis of TPT1-AS1 effects on GC cell proliferation, migration, and invasion. TPT1-AS1 expression was determined in 76 pairs of GC tissues vs. matched adjacent normal tissues and in four GC cell lines (SGC-7901, AGS, BGC-823, and MGC-803) vs. GES-1 cell line by quantitative reverse transcription PCR. SGC-7901 and MGC-803 cells were transfected with small interfering RNA or scrambled negative control, and cell proliferation, colony formation, migration, invasion and cell cycle assays were performed. The expression of proteins involved in cell cycle progression and epithelial-mesenchymal transition was analyzed by Western blot. TPT1-AS1 expression was significantly higher in GC tissues and cell lines compared to controls. The overexpression of TPT1-AS1 was significantly correlated with TNM stage and lymph node metastasis, and it was associated with worse prognosis of GC patients according to the Kaplan-Meier survival analysis and Cox proportional hazard regression analysis. The knockdown of TPT1-AS1 significantly inhibited proliferation, cell cycle G1/S transition, migration, and invasion of SGC-7901 and MGC-803 cells. Moreover, TPT1-AS1 knockdown downregulated the expression of cyclin-dependent kinase (CDK) 4, cyclin D1, and vimentin and upregulated the expression of p21 and E-cadherin. Our findings suggest that TPT1-AS1 may be a promising therapeutic target in GC.

lncRNA CASC19 Contributes to Radioresistance of Nasopharyngeal Carcinoma by Promoting Autophagy via AMPK-mTOR Pathway

Nasopharyngeal carcinoma (NPC) is one of the most frequent head and neck malignant tumors and is majorly treated by radiotherapy. However, radiation resistance remains a serious obstacle to the successful treatment of NPC. The aim of this study was to discover the underlying mechanism of radioresistance and to elucidate novel genes that may play important roles in the regulation of NPC radiosensitivity. By using RNA-seq analysis of NPC cell line CNE2 and its radioresistant cell line CNE2R, lncRNA CASC19 was screened out as a candidate radioresistance marker. Both in vitro and in vivo data demonstrated that a high expression level of CASC19 was positively correlated with the radioresistance of NPC, and the radiosensitivity of NPC cells was considerably enhanced by knockdown of CASC19. The incidence of autophagy was enhanced in CNE2R in comparison with CNE2 and another NPC cell line HONE1, and silencing autophagy with LC3 siRNA (siLC3) sensitized NPC cells to irradiation. Furthermore, CASC19 siRNA (siCASC19) suppressed cellular autophagy by inhibiting the AMPK/mTOR pathway and promoted apoptosis through the PARP1 pathway. Our results revealed for the first time that lncRNA CASC19 contributed to the radioresistance of NPC by regulating autophagy. In significance, CASC19 might be a potential molecular biomarker and a new therapeutic target in NPC.

Long noncoding RNA MIR99AHG promotes gastric cancer progression by inducing EMT and inhibiting apoptosis via miR577/FOXP1 axis

Background

Long non-coding RNAs (lncRNAs) play a vital role in the genesis and development of human cancer. LncRNA MIR99AHG has been reported to be upregulated in acute myeloid leukemia (AML); however, its function in gastric cancer (GC) is still not clear. Here we were aiming to screen the prognostic lncRNA candidates and to explore the function of MIR99AHG in GC.

Methods

We have preliminarily screened some candidate lncRNA biomarkers in GC tissues through analyzing microarray datasets. The expression level of MIR99AHG in GC cell lines and tissues was monitored via qPCR. Survival analysis was performed with the patients of our hospital and TCGA database cases. CCK-8 assay, trans-well assay and flow cytometry were performed to determine cell proliferation, invasion, migration and apoptosis. Meanwhile, a target of MIR99AHG was predicted and identified by luciferase reporter gene detection experiments.

Results

MIR99AHG was strongly up-regulated in human GC and contributed to cancer progression. Kaplan–Meier analysis revealed that up-regulating MIR99AHG expression was positively correlated with unfavorable overall survival (P < 0.01) of patients from our hospital and TCGA database. Knockdown of MIR99AHG expression inhibited cell proliferation, invasion, migration and promoted cell apoptosis. Moreover, MIR99AHG worked as an oncogenic gene though competing for endogenous RNA (ceRNA) of miR-577.

Conclusions

Our findings suggested that MIR99AHG contributes to malignant phenotypes of GC and may become a promising therapeutic target.

SNHG9 was upregulated in NSCLC and associated with DDP-resistance and poor prognosis of NSCLC patients

Lung cancer, a leading cause of cancer-related mortalities worldwide and non-small cell lung cancer (NSCLC) is the main subtype of lung cancer. As a first-line chemotherapeutic drug used for NSCLC, acquired resistance retarded the clinical application of cisplatin (DDP). We herein reported long non-coding RNA SNHG9 was over-expressed in NSCLC tissues and cell lines compared with normal lung tissues and cell line; Increased SNHG9 was also observed in DDP resistant NSCLC tissues and cell lines compared with their DDP sensitive counterparts. Elevated expression of SNHG9 was associated with lower overall survival (OS) rate in NSCLC patients. Besides, silence of SNHG9 suppressed DDP resistance of NSCLC cells. Furthermore, CAPRIN1 was positively regulated by SNHG9 and mediated the promoting role of SNHG9 in DDP resistance of NSCLC cells. SNHG9 could be used as a potential target for DDP resistant NSCLC therapy.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

LINC01272 Promotes Migration and Invasion of Gastric Cancer Cells via EMT

PURPOSE

Gastric cancer (GC) is the fifth most common tumor in the world, and most patients with GC have a poor prognosis. This study aimed to explore the biological influence and mechanism of LINC01272 in GC.

MATERIALS AND METHODS

Using bioinformatic analyses, we investigated the expression of LINC01272 in TCGA database and predicted the biological functions and mechanism of LINC01272 in GC. Then, we detected the expression of LINC01272 in GC cell lines, GC tissues, and corresponding normal tissues using real-time polymerase chain reaction (RT-PCR). Finally, we explored the migration and invasion ability of LINC01272 by wound-healing and Transwell assays and examined the expression of epithelial-mesenchymal transition (EMT)-related proteins through Western blotting.

RESULTS

We found that LINC01272 was upregulated in GC and was associated with GC staging and lymph node metastasis. The results of wound-healing and Transwell assays revealed that the LINC01272 was closely related to GC cell migration and invasion. LINC01272 knockdown inhibited the migration and invasion ability of GC cells by reducing the expression of EMT-related proteins. Overexpression of LINC01272 had the opposite effect.

CONCLUSION

Together, our results showed that LINC01272 promoted GC metastasis ability by regulating the expression of EMT-related proteins and could serve as a potential diagnostic biomarker for GC.

Long Non-Coding RNA CASC19 Sponges microRNA-532 and Promotes Oncogenicity of Clear Cell Renal Cell Carcinoma by Increasing ETS1 Expression

Purpose

The long non-coding RNA cancer susceptibility 19 (CASC19) is recognized as an important regulator in gastric cancer, colorectal cancer, and non-small cell lung cancer. Nevertheless, to the best of our knowledge, the expression status and detailed roles of CASC19 in clear cell renal cell carcinoma (ccRCC) have not been elucidated. Hence, we aimed to determine CASC19 expression in ccRCC and investigate its roles in ccRCC oncogenicity. The molecular mechanisms underlying CASC19 functions in ccRCC were also determined.

Methods

CASC19 expression was measured by using reverse transcription-quantitative polymerase chain reaction. The effects of CASC19 on ccRCC cell proliferation, colony formation, migration, and invasiveness in vitro, as well as on tumor growth in vivo, were examined by the MTT assay, colony formation assay, cell migration and invasiveness assays, and tumor xenograft in nude nice, respectively.

Results

CASC19 was overexpressed in ccRCC tissues and cell lines. High expression of CASC19 was closely associated with unfavorable clinicopathological parameters and predicted negative clinical outcomes in patients with ccRCC. Knockdown of CASC19 decreased ccRCC cell proliferation, colony formation, migration, and invasiveness, as well as attenuated tumor growth in vivo. Mechanistically, CASC19 functioned as a competing endogenous RNA and upregulated the expression of ETS proto-oncogene 1 (ETS1) through sponging microRNA-532 (miR-532). Furthermore, rescue assays revealed that inhibiting miR-532 or restoring ETS1 expression partially abolished the impacts of CASC19 knockdown on ccRCC cells.

Conclusion

The CASC19/miR-532/ETS1 regulatory pathway is crucial for the malignant manifestations of ccRCC, which makes it an attractive target for potential treatments of ccRCC.

Long Non-Coding RNA TMPO-AS1 Promotes Cell Migration and Invasion by Sponging miR-140-5p and Inducing SOX4-Mediated EMT in Gastric Cancer

Background

Mounting evidence show that long non-coding RNAs (lncRNAs) play critical roles in the progression of various human cancers, including gastric cancer (GC), a common gastrointestinal tumor. In this study, the biological functions of lncRNA TMPO-AS1 in GC were studied.

Methods

TMPO-AS1 and miR-140-5p expression levels were detected in GC tissues and cell lines by RT-qPCR analysis. Knockdown or overexpression of TMPO-AS1 was conducted to evaluate the effects of TMPO-AS1 on the malignant behaviors of GC cells. Bioinformatic prediction and dual-luciferase reporter assay were performed to investigate the direct interaction between TMPO-AS1 and miR-140-5p in GC.

Results

We observed that TMPO-AS1 was up-regulated in GC tissues, and high TMPO-AS1 expression in GC patients was closely correlated with aggressive clinicopathologic characteristics and poor overall survival. Functionally, gain- and loss-of-function studies showed that TMPO-AS1 overexpression enhanced the proliferation, migration, invasion and EMT of GC cells in vitro, whereas knockdown of TMPO-AS1 inhibited these malignant traits. Importantly, we demonstrated that TMPO-AS1 could function as a competing endogenous RNA (ceRNA) by sponging miR-140-5p in GC cells, thereby diminishing the inhibition on SOX4, an EMT regulator.

Conclusion

Our findings indicated that TMPO-AS1 promotes GC progression partly by regulating miR-140-5p/SOX4 axis, and may serve as a novel therapeutic target for GC.