Emerging Roles of Long Noncoding RNA Regulator of Reprogramming in Cancer Treatment

Extracellular vesicles in gastric cancer: role of exosomal lncRNA and microRNA as diagnostic and therapeutic targets

Extracellular vesicles (EVs), including exosomes, play a crucial role in intercellular communication and have emerged as important mediators in the development and progression of gastric cancer. This review discusses the current understanding of the role of EVs, particularly exosomal lncRNA and microRNA, in gastric cancer and their potential as diagnostic and therapeutic targets. Exosomes are small membrane-bound particles secreted by both cancer cells and stromal cells within the tumor microenvironment. They contain various ncRNA and biomolecules, which can be transferred to recipient cells to promote tumor growth and metastasis. In this review, we highlighted the importance of exosomal lncRNA and microRNA in gastric cancer. Exosomal lncRNAs have been shown to regulate gene expression by interacting with transcription factors or chromatin-modifying enzymes, which regulate gene expression by binding to target mRNAs. We also discuss the potential use of exosomal lncRNAs and microRNAs as diagnostic biomarkers for gastric cancer. Exosomes can be isolated from various bodily fluids, including blood, urine, and saliva. They contain specific molecules that reflect the molecular characteristics of the tumor, making them promising candidates for non-invasive diagnostic tests. Finally, the potential of targeting exosomal lncRNAs and microRNAs as a therapeutic strategy for gastric cancer were reviewed as wee. Inhibition of specific molecules within exosomes has been shown to suppress tumor growth and metastasis in preclinical models. In conclusion, this review article provides an overview of the current understanding of the role of exosomal lncRNA and microRNA in gastric cancer. We suggest that further research into these molecules could lead to new diagnostic tools and therapeutic strategies for this deadly disease.

[LINC01285 promotes proliferation and metastasis of colorectal cancer cells by regulating epithelial-mesenchymal transition]

OBJECTIVE

To clarify the mechanism by which LINC01285 regulates proliferation and migration of colorectal cancer (CRC) cells and the clinical implications.

METHODS

We analyzed the expression of LINC01285 in CRC tissues and normal tissues using data from Starbase public database. We also examined the expression levels of LINC01285 in 70 pairs of CRC and adjacent tissue samples collected from our center and in different CRC cell lines using RT-qPCR, and analyzed the correlation of LINC01285 expression with the clinicopathological parameters and tumor-free survival time of the patients. In CRC cell lines (SW620 and HT-29), the changes in cell proliferation, apoptosis, metastasis and epithelial-mesenchymal transition (EMT) phenotype following LINC01285 knockdown were analyzed using CCK-8 assay, flow cytometry, Transwell assay and Western blotting.

RESULTS

The TCGA-COAD transcriptome sequencing data obtained from the Starbasev3.0 public database revealed a significantly higher expression level of LINC01285 in CRC tissues than in adjacent tissues (P=0.00016), which was verified by RT-qPCR results of the clinical samples (P=0.0002). In CRC patients, the expression level of LINC01285 was closely correlated with histological differentiation of the tumor (P=0.036), T classification (P=0.000), lymph node metastasis (P=0.001), TNM stage (P=0.000), Duke stage (P=0.009) and relapse-free survival (P=0.0102). In SW620 and HT-29 cells, which expressed significantly higher levels of LINC01285 than normal colorectal mucosal cells (P < 0.001), LINC01285 knockdown significantly inhibited cell proliferation (P < 0.001), increased early apoptosis, late apoptosis and total apoptosis rates (P < 0.05), suppressed cell migration and invasion (P < 0.001), upregulated the expression of E-cadherin (P < 0.001), and downregulated the expression of N-cadherin (P < 0.001).

CONCLUSION

The expression level of LINC01285, which modulates the EMT pathway to regulate the proliferation, apoptosis and metastasis of CRC cells, is closely correlated with the prognosis of CRC patients.

LncRNA SNHG3 promoted cell proliferation, migration, and metastasis of esophageal squamous cell carcinoma via regulating miR-151a-3p/PFN2 axis

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignant tumor with a poor prognosis. The dysregulation of long non-coding RNAs (lncRNAs) is closely related to the tumorigenesis and progression of ESCC. However, the effects of lncRNA small nucleolar RNA host gene 3 (lncRNA SNHG3) in ESCC are still unclear. Therefore, a series of experiments methods, such as quantitative real-time polymerase chain reaction, function gain/loss experiments, western blots, and animal xenograft tumor model, were employed to explore the biological function and molecular mechanism of SNHG3 in ESCC. As results, we first reported that SNHG3 was significantly up-regulated in ESCC tissues and cells. SNHG3 knockdown obviously inhibited cell proliferation, migration, invasion, and promoted apoptosis. Mechanism analysis revealed that SNHG3 sponged miR-151a-3p to regulate PFN2. Inhibition of miR-151a-3p and overexpression of PFN2 attenuated the positive effect of SNHG3 knockdown on suppressing tumor progression. Furthermore, the anti-tumor effects of SNHG3 knockdown were also observed in vivo. In summary, our results indicated that SNHG3 knockdown suppressed tumor development via the miR-151a-3p/PFN2 axis, and targeting SNHG3 may provide a new opportunity for ESCC patients.

Functions of long non-coding RNA ROR in patient-derived glioblastoma cells

Glioblastoma (GBM) is the most frequent and aggressive primary brain cancer in adult patients. A variety of long non-coding RNAs play an important role in the pathogenesis of GBM, however the molecular functions of most of them still remain elusive. Here, we investigated linc-RoR (long intergenic non-protein coding RNA, regulator of reprogramming) using GBM neurospheres obtained from 12 different patients. We demonstrated that the highest level of this transcript is detected in cells with increased EGFR expression. According to our data, linc-RoR knockdown decreases cell proliferation, increases sensitivity to DNA damage, and downregulates the level of cancer stem cell (CSC) markers. On the other hand, linc-RoR overexpression promote cell growth and increases the proportion of CSCs. Analysis of RNA sequencing data revealed that linc-RoR affects expression of genes involved in the regulation of mitosis. In agreement with this observation, we have showen that the highest level of linc-RoR is detected in the G2/M phase of the cell cycle, when linc-RoR is localized on the chromosomes of dividing cells. Based on our results, we can propose that linc-RoR performs pro-oncogenic functions in human gliobalstoma cells, which may be associated with the regulation of mitotic progression and GBM stemness.

LINC00261 Inhibits Esophageal Cancer Radioresistance by Down-Regulating microRNA-552-3p and Promoting DIRAS1

OBJECTIVE

Esophageal cancer (EC) represents a life-threatening tumor with an ever-increasing incidence rate. Long intergenic non-protein coding RNAs (LINCs) have also become a topic of interest in EC. In a similar light, the current study aimed to investigate the role of LINC00261 in EC radioresistance.

METHODS

Firstly, radioresistant EC cell lines TE-1-R and TE-5-R were established using TE-1 and TE-5 cells. Subsequently, LINC00261, microRNA (miR)-552-3p, and DIRAS1 expression patterns in EC tissues and adjacent normal tissues and EC cells were evaluated. In addition, survival fraction (SF), colony formation, apoptosis, and γ-H2AX levels were analyzed, followed by the detection of the binding relation between LINC00261 and miR-552-3p and between miR-552-3p and DIRAS1. Lastly, xenograft transplantation was carried out to confirm the effects of LINC00261 on EC radioresistance in vivo.

RESULTS

LINC00261 and DIRAS1 were poorly-expressed in EC tissues and cells, but miR-552-3p was over-expressed. In EC cells with X-ray radiation, over-expression of LINC00261 reduced SF and cell viability, strengthened γ-H2AX levels, and promoted apoptosis, while all these trends were counteracted by miR-522-3p over-expression or DIRAS1 silencing. Mechanistic investigation further validated the binding relation between LINC00261 and miR-552-3p, and between miR-552-3p and DIRAS1. Moreover, LINC00261 over-expression suppressed tumor growth and reduced EC radioresistance in vivo.

CONCLUSION

Altogether, our findings indicated that LINC00261 exerts a suppressive effect on EC radioresistance via the competing endogenous RNA network to sponge miR-552-3p and up-regulate DIRAS1 transcription.

lncRNA and breast cancer: Progress from identifying mechanisms to challenges and opportunities of clinical treatment

Breast cancer is a malignant tumor that has a high mortality rate and mostly occurs in women. Although significant progress has been made in the implementation of personalized treatment strategies for molecular subtypes in breast cancer, the therapeutic response is often not satisfactory. Studies have reported that long non-coding RNAs (lncRNAs) are abnormally expressed in breast cancer and closely related to the occurrence and development of breast cancer. In addition, the high tissue and cell-type specificity makes lncRNAs particularly attractive as diagnostic biomarkers, prognostic factors, and specific therapeutic targets. Therefore, an in-depth understanding of the regulatory mechanisms of lncRNAs in breast cancer is essential for developing new treatment strategies. In this review, we systematically elucidate the general characteristics, potential mechanisms, and targeted therapy of lncRNAs and discuss the emerging functions of lncRNAs in breast cancer. Additionally, we also highlight the advantages and challenges of using lncRNAs as biomarkers for diagnosis or therapeutic targets for drug resistance in breast cancer and present future perspectives in clinical practice.

Up-Regulation of LINC00665 Facilitates the Malignant Progression of Prostate Cancer by Epigenetically Silencing KLF2 Through EZH2 and LSD1

This study aimed to explore the function of LINC00665 on the proliferation and metastasis of prostate cancer (PCa), and the potential regulatory mechanisms were also investigated. The expression level of LINC00665 in 50 pairs of PCa tissues and adjacent ones was studied by qRT-PCR, and the associations between LINC00665 and clinicopathological characteristics of PCa patients were analyzed. Control group (sh-NC) and LINC00665 knock-down group (sh-LINC00665) were set in 22RV1 and DU145 cells, respectively. The biological functions of LINC00665 in PCa cell lines were assessed by CCK-8, EdU, Transwell assays, and the nude mouse xenograft model was used to evaluate the tumorigenicity in vivo. In addition, qRT-PCR, Western Blot, RIP and ChIP assays were also used to determine the regulation mechanism of LINC00665 in PCa cell lines. In this study, our results showed that LINC00665 expression level in PCa cancer tissues was significantly up-regulated, compared with that in adjacent ones. Besides, similar results were found in PCa cell lines. Knock-down of LINC00665 significantly attenuated the proliferation and migration ability in 22RV1 and DU145 cells, compared to sh-NC. Mechanically, LINC00665 could interact with EZH2 and LSD1, recruiting them to KLF2 promoter region to inhibit its transcription. Moreover, the tumor-suppressive effects mediated by sh-LINC00665 were significantly reversed through the down-regulation of KLF2. Also, the suppression of LINC00665 impaired tumor growth of PCa in vivo. In summary, LINC00665 exerted the oncogenic functions in PCa cell lines by epigenetically silencing KLF2 expression by binding to EZH2 and LSD1, illuminating a novel mechanism of LINC00665 in the malignant progression of PCa and furnishing a prospective therapeutic biomarker to combat PCa.

Long Intergenic Non-Protein Coding RNA 519 Promotes the Biological Activities of Tongue Squamous Cell Carcinoma by Sponging microRNA-876-3p and Consequently Upregulating MACC1

Purpose

Long intergenic non-protein coding RNA 519 (LINC00519) promotes the development of lung squamous cell carcinoma. In this study, we detected the expression of LINC00519 in tongue squamous cell carcinoma (TSCC) and examined its clinical significance. Additionally, the regulatory effects of LINC00519 on behaviors of TSCC tumor cells were explored through functional experiments. Finally, mechanistic studies were performed to elucidate the molecular events underlying the tumor-promoting actions of LINC00519 in TSCC.

Materials and Methods

The expression of LINC00519 in TSCC tissues and cell lines was determined using quantitative reverse transcription-polymerase chain reaction. Cell counting kit-8 assay, flow cytometric analysis, cell migration and invasion assays and xenograft tumor model analyses were used to detect TSCC cell proliferation, apoptosis, migration and invasion and in vivo tumor growth, respectively. Mechanistic studies were performed using bioinformatics analysis, RNA immunoprecipitation assay, luciferase reporter assay and rescue experiments.

Results

LINC00519 was overexpressed in both TSCC tissues and cell lines. A high LINC00519 level was associated with poor overall survival in patients with TSCC. In vitro, LINC00519 played cancer-promoting roles in TSCC progression by facilitating cell proliferation, migration and invasion and restraining cell apoptosis. In vivo, LINC00519 downregulation resulted in decreased TSCC tumor growth. Mechanistically, LINC00519 acted as a competing endogenous RNA for microRNA-876-3p (miR-876-3p), which directly targets metastasis associated with colon cancer-1 (MACC1), in TSCC cells. LINC00519 upregulated the expression of MACC1 in TSCC cells by sequestering miR-876-3p. Rescue experiments further affirmed that miR-876-3p inhibition or MACC1 overexpression mitigated the inhibitory influences of LINC00519 depletion on cell proliferation, migration and invasion and neutralized the promoting actions of LINC00519 knockdown on cell apoptosis in TSCC.

Conclusion

LINC00519 aggravated the oncogenicity of TSCC by regulating the miR-876-3p/MACC1 axis. Our findings suggest that the LINC00519/miR-876-3p/MACC1 pathway may be an underlying therapeutic target in TSCC.

Long non‑coding RNA JPX promotes gastric cancer progression by regulating CXCR6 and autophagy via inhibiting miR‑197

Long non-coding RNAs (lncRNAs) serve a crucial role in gastric cancer (GC) progression. However, the molecular mechanism underlying lncRNA JPX transcript, XIST activator (JPX) in the tumorigenesis of GC is not completely understood. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were performed to detect gene expression. A luciferase reporter gene assay was conducted to determine the relationship between microRNA (miR)-197 and JPX or C-X-C motif chemokine receptor 6 (CXCR6). Cell viability, migration and invasion were determined by performing MTT, wound healing and Transwell assays, respectively. The Cancer Genome Atlas database and the RT-qPCR results indicated that JPX expression was upregulated and miR-197 expression was downregulated in patients with GC and in GC cells. Moreover, high JPX expression and low miR-197 expression in patients with GC indicated poor prognosis. miR-197 expression was directly inhibited by JPX. Compared with the short hairpin RNA (sh) negative control (NC) group, NCI-N87 and MKN-45 cells in the shJPX group displayed decreased cell viability and invasion, as well as a wider scratch width. NCI-N87 and MKN-45 cells in the shJPX + miR-197 inhibitor group had increased viability and invasion, but a narrower scratch width compared with the shJPX group. It was also identified that miR-197 directly inhibited CXCR6 expression. miR-197 inhibited Beclin1 protein expression and promoted p62 protein expression. Compared with the NC group, NCI-N87 and MKN-45 cells in the miR-197 mimic group had decreased cell viability and invasion, and a wider scratch width. Enhanced cell viability and invasion, and a narrower scratch width was also observed in the miR-197 mimic + CXCR6 and miR-197 mimic + Beclin1 groups, compared with the miR-197 mimic group. Collectively, the results indicated that lncRNA JPX promoted GC progression by regulating CXCR6 and autophagy via inhibiting miR-197. Furthermore, JPX knockdown regulated GC cell phenotype by promoting miR-197.