LncRNA LINC00342 promotes gastric cancer progression by targeting the miR-545-5p/CNPY2 axis

Long Non-coding RNA LINC00342 Promotes the Proliferation, Invasion, and Migration of Primary Hepatocellular Carcinoma Cells by Regulating the Expression of miRNA-19a-3p, miRNA-545-5p, and miRNA-203a-3p

This study aimed to investigate the role of the long non-coding RNA (lncRNA) LINC00342-207 (LINC00342) in the development and progression of primary hepatocellular carcinoma (HCC). Forty-two surgically resected HCC tissues and corresponding paracancerous tissues were collected from October 2019 to December 2020 and examined for lncRNA LINC00342, microRNA (miR)-19a-3p, miR-545-5p, miR-203a-3p, cell cycle protein D1 (CyclinD1/CCND1), murine double minute 2 (MDM2), and fibroblast growth factor 2 (FGF2) expression. The disease-free survival and overall survival of patients with HCC were followed up. HCC cell lines and the normal hepatocyte cell line HL-7702 were cultured and the expression level of LINC00342 was measured. HepG2 cells were transfected with LINC00342 siRNA, LINC00342 overexpression plasmid, miR-19a-3p mimics and their corresponding suppressors, miR-545-5p mimics and their corresponding suppressors, and miR-203a-3p mimics and their corresponding suppressors. The proliferation, apoptosis, migration, and invasion of HepG2 cells were detected. Stably transfected HepG2 cells were inoculated into the left axilla of male BALB/c nude mice, and the volume and quality of transplanted tumors as well as the expression levels of LINC00342, miR-19a-3p, miR-545-5p, miR-203a-3p, CCND1, MDM2, and FGF2 were examined. LINC00342 played an oncogenic role in HCC and exhibited inhibitory effects on proliferation, migration, and invasion, and promoted the apoptosis of HepG2 cells. Moreover, it inhibited the growth of transplanted tumors in vivo in mice. Mechanistically, the oncogenic effect of LINC00342 was associated with the targeted regulation of the miR-19a-3p/CCND1, miR-545-5p/MDM2, and miR-203a-3p/FGF2 axes.

[LncRNA LINC00342 regulates gastric cancer cell proliferation, migration and invasion by targeting miR-596]

OBJECTIVE

To investigate the expression levels of LINC00342 in gastric cancer (GC) tissues and cells and the pathways mediating its effects on biological behaviors of GC cells.

METHODS

Bioinformatic analysis was performed to identify the lncRNAs and their downstream miRNAs involved in regulation of biological behaviors of GC cells. qRT-PCR was used to analyze the differential expression of LINC00342 and miR-596 in GC cell lines, human gastric mucosal cells, and GC and adjacent tissues. In human GC MGC-803 and MGC-823 cells, the effects of LINC00342 overexpression, miR-596 overexpression, LINC00342 knockdown, or miR-596 knockdown on cell proliferation, migration, invasion and cell cycle changes were examined using Edu assay, CCK-8 assay, wound healing assay, Transwell assay, and flow cytometry. The regulatory interaction between LINC00342 and miR-596 was investigated using a dual-luciferase reporter assay.

RESULTS

Informatic analysis identified LINC00342 as the candidate lncRNA regulating biological behaviors of GC cells, with miR-596 as its downstream miRNA. LINC00342 expression levels were significantly higher while miR-596 expression levels were lower in GC tissues and cell lines than in the paired adjacent tissues and human gastric mucosal cell lines (all P<0.05). In MGC-803 and MGC-823 cells, overexpression of LINC00342 significantly enhanced cell proliferation (P<0.05), migration (P<0.01), and invasion (P<0.001) and reduced the percentage of G0/G1 phase cells (P<0.01), while knocking down LINC00342 significantly suppressed cell proliferation (P<0.05), migration (P<0.01), and invasion (P<0.001) and increased G0/G1 phase cell percentage (P<0.01). Modulation of miR-596 expression levels produced the opposite effects. Dual-luciferase reporter assay confirmed the specific binding between LINC00342 and miR-596 (P=0.0067).

CONCLUSION

In GC cells, LINC00342 regulates cell proliferation, migration, and invasion by targeting miR-596.

LncRNA and its role in gastric cancer immunotherapy

Gastric cancer (GC) is a potential dominant disease in tumor immunotherapy checkpoint inhibitors, and adoptive cell therapy have brought great hope to GC patients. However, only some patients with GC can benefit from immunotherapy, and some patients develop drug resistance. More and more studies have shown that long non-coding RNAs (lncRNAs) may be important in GC immunotherapy's prognosis and drug resistance. Here, we summarize the differential expression of lncRNAs in GC and their impact on the curative effect of GC immunotherapy, discuss potential mechanisms of activity in GC immunotherapy resistance regulated by lncRNAs. This paper reviews the differential expression of lncRNA in GC and its effect on immunotherapy efficacy in GC. In terms of genomic stability, inhibitory immune checkpoint molecular expression, the cross-talk between lncRNA and immune-related characteristics of GC was summarized, including tumor mutation burden (TMB), microsatellite instability (MSI), and Programmed death 1 (PD-1). At the same time, this paper reviewed the mechanism of tumor-induced antigen presentation and upregulation of immunosuppressive factors, as well as the association between Fas system and lncRNA, immune microenvironment (TIME) and lncRNA, and summarized the functional role of lncRNA in tumor immune evasion and immunotherapy resistance.

Low expression of lncRNA APTR promotes gastric cancer progression

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APTR is actively expressed in gastric cancer cells.

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Low expression of APTR is associated with poor clinical characteristics in patients with gastric cancer.

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Silencing APTR promotes gastric cancer proliferation and invasiveness.

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APTR expression is negatively associated with inflammatory signaling in the gastric tumor microenvironment.

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LncRNA APRT is a potential biomarker for gastric cancer patients' diagnosis and prognosis, and could be a potential therapeutic target.

Background

Gastric cancer (GC) is one of the most common cancers worldwide and the majority of GC patients are diagnosed at advanced stages due to the lack of early detection biomarkers. LncRNAs have been shown to play important roles in various diseases and could be predictive biomarkers and therapeutic targets. Our study demonstrated that low expression of lncRNA APTR could promote gastric cancer progression.

Methods

Differentiated expressed lncRNAs were identified through analyzing TCGA paired GC RNA sequencing data. LncRNA APTR's clinical relevance was analyzed using the TCGA dataset and GEO datasets. APTR expression in patient samples was detected through qPCR. The proliferation, colony formation, and migration of GC cells were tested. Bioinformatic analyses were performed to explore APTR-affected signaling pathways in GC.

Results

LncRNA APTR is lower expressed in gastric tumor samples and low expression of APTR predicts a poor diagnosis and outcome in GC patients. Silencing APTR promotes gastric cancer proliferation and invasiveness. APTR expression is negatively correlated with inflammatory signaling in the gastric tumor microenvironment.

Conclusion

Our study showed that low expression of lncRNA APTR in gastric cancer is correlated with tumorigenesis and poor diagnosis and prognosis, which is a potential biomarker for gastric cancer patients' diagnosis and treatment.

Long Noncoding RNA: Shining Stars in the Immune Microenvironment of Gastric Cancer

Gastric cancer (GC) is a kind of malignant tumor disease that poses a serious threat to human health. The GC immune microenvironment (TIME) is a very complex tumor microenvironment, mainly composed of infiltrating immune cells, extracellular matrix, tumor-associated fibroblasts, cytokines and chemokines, all of which play a key role in inhibiting or promoting tumor development and affecting tumor prognosis. Long non-coding RNA (lncRNA) is a non-coding RNA with a transcript length is more than 200 nucleotides. LncRNAs are expressed in various infiltrating immune cells in TIME and are involved in innate and adaptive immune regulation, which is closely related to immune escape, migration and invasion of tumor cells. LncRNA-targeted therapeutic effect prediction for GC immunotherapy provides a new approach for clinical research on the disease.