LONG-NONCODING RNAs in gastroesophageal cancers

Potential Clinical Role of LncRNA miR503HG in Multiple Myeloma and its Effect on the Proliferation and Adhesion of Myeloma Cells

This study mainly explored the role of lncRNA miR503HG in multiple myeloma and the potential downstream regulatory mechanism affecting disease. Real-time quantitative polymerase chain reaction was used to measure the expression levels of miR503HG and miR-103. A cell counting kit-8 assay was performed to detect cell viability. The concentrations of adhesion-related factors (MUC-1, VCAM-1, ICAM-1) were determined using enzyme-linked immunosorbent assay. The targeting relationship between miR503HG and miR-103 was detected by dual-luciferase reporter assay. The miR503HG expression in peripheral blood of multiple myeloma patients was lower than that of normal healthy individuals and associated with ISS stage and worse overall survival. miR-103 was identified as the downstream target of miR503HG. Upregulation of miR503HG could inhibit cell proliferation and adhesion of multiple myeloma cell lines, which could partially reverse the inhibition of adhesion and proliferation by high expression of miR-103. lncRNA miR503HG expression was downregulated in multiple myeloma and had potential diagnostic/prognostic value. MiR503HG exerts a molecular sponge effect on miR-103 and affects its expression, thus achieving the inhibitory effect on multiple myeloma.

Effect of tumor exosome-derived Lnc RNA HOTAIR on the growth and metastasis of gastric cancer

PURPOSE

HOX transcribed antisense RNA (HOTAIR) is a long noncoding RNA (LncRNA) that promotes tumor progression. Exosomes are critically involved in cancer progression. The presence of HOTAIR in the circulating exosomes and the roles of exosomal HOTAIR in gastric cancer (GC) remains unknown. This study aimed to investigate the role of HOTAIR in exosomes in promoting the growth and metastasis of GC.

METHODS

Serum exosomes from GC patients were captured by CD63 immunoliposome magnetic spheres (CD63-IMS), and the biological characteristics of the exosomes were identified. The expression levels of HOTAIR in GC cells, tissues, serum and serum exosomes were detected by fluorescence quantitative PCR (qRT-PCR), and the clinicopathological correlation was statistically analyzed. The growth and metastasis abilities of GC cells with HOTAIR knockdown in vitro were evaluated by cell experiment. The effects of HOTAIR highly-expressed NCI-N87 cell-derived exosomes were used to treat HOTAIR lowly-expressed MKN45 cells on GC growth and metastasis were also evaluated.

RESULTS

The exosomes isolated by CD63-IMS had a particle size of 89.78 ± 4.8 nm and were oval membranous particles. The expression of HOTAIR in tumor tissues and serum of GC patients was increased (P < 0.05), and the expression of HOTAIR in serum exosomes was significantly increased (P < 0.01). The in NCI-N87 and MKN45 cell experiment demonstrated that HOTAIR knockdown by RNA interference suppressed cell growth and metastasis in NCI-N87 cells. Coculture of exosomes secreted by NCI-N87 cells with MKN45 cells significantly increased the expression of HOTAIR, and enhanced cell growth and metastasis.

CONCLUSION

LncRNA HOTAIR can be used as a potential biomarker which provides a new way for the diagnosis and treatment of GC.

The Prognostic Impact of Gender, Therapeutic Strategies, Molecular Background, and Tumor-Infiltrating Lymphocytes in Glioblastoma: A Still Unsolved Jigsaw

Despite the adoption of novel therapeutical approaches, the outcomes for glioblastoma (GBM) patients remain poor. In the present study, we investigated the prognostic impact of several clinico-pathological and molecular features as well as the role of the cellular immune response in a series of 59 GBM. CD4+ and CD8+ tumor-infiltrating lymphocytes (TILs) were digitally assessed on tissue microarray cores and their prognostic role was investigated. Moreover, the impact of other clinico-pathological features was evaluated. The number of CD4+ and CD8+ is higher in GBM tissue compared to normal brain tissue (p < 0.0001 and p = 0.0005 respectively). A positive correlation between CD4+ and CD8+ in GBM is present (rs = 0.417-p = 0.001). CD4+ TILs are inversely related to overall survival (OS) (HR = 1.79, 95% CI 1.1-3.1, p = 0.035). The presence of low CD4+ TILs combined with low CD8+ TILs is an independent predictor of longer OS (HR 0.38, 95% CI 0.18-0.79, p = 0.014). Female sex is independently related to longer OS (HR 0.42, 95% CI 0.22-0.77, p = 0.006). Adjuvant treatment, methylguanine methyltransferase (MGMT) promoter methylation, and age remain important prognostic factors but are influenced by other features. Adaptive cell-mediated immunity can affect the outcomes of GBM patients. Further studies are needed to elucidate the commitment of the CD4+ cells and the effects of different TILs subpopulations in GBM.

LncRNA GACAT3: A Promising Biomarker and Therapeutic Target in Human Cancers

Long non-coding RNAs (lncRNAs) are a class of functional RNA molecules that do not encode proteins and are composed of more than 200 nucleotides. LncRNAs play important roles in epigenetic and gene expression regulation. The oncogenic lncRNA GACAT3 was recently discovered to be dysregulated in many tumors. Aberrant expression of GACAT3 contributes to clinical characteristics and regulates multiple oncogenic processes. The association of GACAT3 with a variety of tumors makes it a promising biomarker for diagnosis, prognosis, and targeted therapy. In this review, we integrate the current understanding of the pathological features, biological functions, and molecular mechanisms of GACAT3 in cancer. Additionally, we provide insight into the utility of GACAT3 as an effective diagnostic and prognostic marker for specific tumors, which offers novel opportunities for targeted therapeutic intervention.

LncRNA HCG11 represses ovarian cancer cell growth via AKT signaling pathway

AIM

Ovarian cancer is a main contributor of cancer-relevant deaths among women worldwide due to high incidence and mortality. Mounting evidence has unveiled that lncRNAs play critical roles in malignancies, including ovarian cancer. Although the tumor suppressor function of HCG11 in prostate cancer and glioma has been proved, investigations on HCG11 role in ovarian cancer are still scarce.

METHODS

Gene or protein expression was quantified by RT-qPCR or western blot. HCG11 effects on ovarian cancer were assessed by functional assays. Bioinformatics analysis and mechanism experiments were implemented to identify the association among HCG11, miR-1270, and PTEN.

RESULTS

HCG11 was weakly expressed in ovarian cancer and functioned as a tumor suppressor in ovarian cancer by retarding cell proliferation, migration, and EMT. Besides, HCG11 could bind to miR-1270 and PTEN was a target gene of miR-1270. Mechanically, HCG11 competitively bound with miR-1270 to upregulate PTEN. From rescue experiments, HCG11 impeded AKT/mTOR pathway to retard ovarian cancer cell growth by miR-1270/PTEN.

CONCLUSIONS

HCG11 was a tumor suppressor in ovarian cancer cells and additionally, HCG11 regulated AKT/mTOR pathway to hinder ovarian cancer cell growth via modulating miR-1270/PTEN, indicating that HCG11 may represent a promising target for effective treatment of ovarian cancer patients.

Rictor Activates Cav 1 Through the Akt Signaling Pathway to Inhibit the Apoptosis of Gastric Cancer Cells

Background

Rapamycin-insensitive companion of mammalian target of rapamycin (Rictor) protein is a core subunit of mammalian target of rapamycin complex 2, and is associated with cancer progression. However, the biological function of Rictor in cancer, particularly its clinical relevance in gastric cancer (GC) remains largely unknown.

Methods

Rictor expression and its association with clinicopathologic characteristics in GC were analyzed by immunohistochemistry. Effect of Rictor and Caveolin-1 (Cav 1) on GC cells apoptosis was evaluated via overexpression experiment in vitro. Mechanisms of Rictor and Cav 1 in GC were explored through overexpression and knockdown, by immunofluorescence and western blot analyses.

Results

Rictor was upregulated in GC, and mainly located in the cytoplasm of cancer cells. Moreover, higher Rictor levels were associated with worse prognosis. Rictor could inhibit GC cell apoptosis and promote cell growth in vitro. The results of immunofluorescence revealed that Cav 1 localized in GC cell membrane but did not co-localize with Rictor. Further, Rictor regulated apoptosis-related proteins, long non-coding RNAs and also activated cellular signaling, thereby positively regulating Cav 1 expression. This effect was attenuated by the Akt inhibitor ly294002. Cav 1 did not significantly affect the ability of Rictor to inhibit tumor cell apoptosis.

Conclusions

Rictor is upregulated in GC and associated with worse prognosis. It inhibits tumor apoptosis and activates Cav 1 through the Akt signaling pathway to inhibit the apoptosis of GC cells. Rictor is, therefore, a promising prognostic biomarker and possible therapeutic target in GC patients.

Mechanism of tumor‑derived extracellular vesicles in regulating renal cell carcinoma progression by the delivery of MALAT1

Renal cell carcinoma (RCC) is a major healthcare burden globally. Tumor-derived extracellular vesicles (EVs) contribute to the formation of a pro-metastatic microenvironment. In the present study, we explored the role and mechanism of RCC cell 786-O-derived EVs (786-O-EVs) in RCC. First, 786-O-EVs were extracted and identified, and EV internalization of RCC cells was observed. RCC cell malignant behaviors and long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) expression patterns were detected before and after 786-O-EV treatment. MALAT1 was intervened to evaluate RCC cell behaviors. The downstream mechanism involving MALAT1 was predicted. In addition, the relationship among MALAT1, transcription factor CP2 like 1 (TFCP2L1) and ETS proto-oncogene 1, transcription factor (ETS1) was analyzed. TFCP2L1 expression patterns were measured after 786-O-EV exposure. Tumor xenograft formation assay and lung metastasis model were adopted to verify the role of 786-O-EVs in vivo in RCC. It was found that 786-O-EVs could be internalized by RCC cells. 786-O-EVs promoted RCC cell malignant behaviors, accompanied by elevated MALAT1 expression levels. The 786-O-EVs with MALAT1 knockdown attenuated the promotive effect of sole 786-O-EVs on RCC cells. MALAT1 located ETS1 in the TFCP2L1 promoter and negatively regulated TFCP2L1, and ETS1 protein could specifically bind to MALAT1. 786-O-EVs enhanced the binding of ETS1 and the TFCP2L1 promoter and decreased TFCP2L1 expression. In vivo, 786-O-EVs promoted tumor growth and RCC lung metastasis, which was suppressed following inhibition of MALAT1. Our findings indicated that 786-O-EVs promoted RCC invasion and metastasis by transporting MALAT1 to promote the binding of transcription factor ETS1 and TFCP2L1 promoter.

ZFPM2-AS1 facilitates cell growth in esophageal squamous cell carcinoma via up-regulating TRAF4

Emerging evidence has confirmed that long noncoding RNAs (lncRNAs) are strongly involved in tumor initiation and development. LncRNA ZFPM2 antisense RNA 1 (ZFPM2-AS1) has been identified as a tumor facilitator in some cancers; nevertheless, its functional significance and regulatory mechanism remain greatly unclear in esophageal squamous cell carcinoma (ESCC). Here, we detected ZFPM2-AS1 expression in ESCC cell lines using qRT-PCR. ZFPM2-AS1 knockdown models were established for investigating the biological function of ZFPM2-AS1 in ESCC cells. The association between miR-3612 and ZFPM2-AS1 or TRAF4 was assessed by RNA pull-down and luciferase reporter assays. The present study indicated that ZFPM2-AS1 was significantly up-regulated in ESCC cells. Functional assays manifested that ZFPM2-AS1 knockdown restrained cell proliferation, migration and invasion, and facilitated cell apoptosis in ESCC. Mechanistically, ZFPM2-AS1 promoted ESCC cell growth and up-regulated TRAF4 to trigger NF-κB pathway by sequestering miR-3612. Besides, miR-3612 was confirmed to be a tumor inhibitor in ESCC. Through restoration experiments, we observed that TRAF4 overexpression could recover the suppressive effect of ZFPM2-AS1 on ESCC cell growth. Collectively, all the results suggested that ZFPM2-AS1 was an oncogene in ESCC cell growth by up-regulating TRAF4 and activating NF-κB pathway.

Long intergenic non-coding RNA (lincRNA)-01317 suppresses human gastric cancer growth by inhibiting migration and invasion of cancer cells

Long intergenic noncoding RNAs (lincRNAs) are strongly associated with several kinds of cancer, including gastric cancer. Here, we found significantly decreased lincRNA-01317 levels in cancer tissue compared with paracancer tissue of patients with gastric cancer, and lincRNA-01317 expression levels positively correlated with clinical survival rate. Furthermore, using a gastric cancer cell line and a xenograft mouse model, we found that transfection of a gastric cancer cell line with lincRNA-01317 significantly inhibited the proliferation, migration, and invasion of gastric cancer cells. Finally, we demonstrated that lincRNA-01317 may target KCNQ1, as KCNQ1 was downregulated after transfection of cells with lincRNA-01317. This study aimed to assess lincRNA-01317 as a potential therapeutic target to treat cancers.

Long Noncoding RNAs in Gastrointestinal Cancer: Tumor Suppression Versus Tumor Promotion

Approximately 80% of the human genome harbors biochemical marks of active transcription that its majority transcribes to noncoding RNAs, namely long noncoding RNAs (lncRNAs). LncRNAs are heterogeneous RNA transcripts that regulate critical biological processes such as cell survival and death. They involve in the progression of different cancers by affecting transcriptional and post-transcriptional modifications as well as epigenetic control of numerous tumor suppressors and oncogenes. Recent findings show that aberrant expression of lncRNAs is associated with tumor initiation, progression, invasion, and overall survival of patients with gastrointestinal (GI) cancers. Some lncRNAs play as tumor suppressors in all GI cancers, but others play as tumor promoters. However, some other lncRNAs might function as a tumor suppressor in one GI cancer, but as a tumor promoter in another GI cancer type. This fact highlights possible context dependency of the expression patterns and roles of at least some lncRNAs in GI cancer development and progression. Here, we review the functional relation of lncRNAs involved in the development and progression of GI cancer by focusing on their roles as tumor suppressor and tumor promoter genes.

Long Noncoding RNAs: New Regulators of Resistance to Systemic Therapies for Gastric Cancer

Gastric cancer (GC) is the second leading cause of cancer mortality and the fourth most commonly diagnosed malignant disease, with approximately 951,000 new cases diagnosed and approximately 723,000 cases of mortality each year. The highest mortality rate of GC is in East Asia, and the lowest is in North America. A large number of studies have demonstrated that GC patients are characterized by higher morbidity, metastasis rates, and mortality and lower early diagnosis rates, radical resection rates, and 5-year survival rates. All cases of GC can be divided into two important stages, namely, early- and advanced-stage GC, and the stage mainly determines the treatment strategy for and the therapeutic effect in GC patients. Patients with early-stage GC undergo radical surgery followed by chemotherapy, and the 5-year survival rate can be as high as 90%. However, patients with advanced-stage GC cannot undergo radical surgery because they are at risk for metastasis; therefore, they can choose only radiotherapy or chemotherapy and have a poor prognosis. Based on the lack of specific clinical manifestations and detection methods, most GC patients (>70%) are diagnosed in the advanced stage; therefore, continued efforts toward developing treatments have been focused on advanced-stage GC patients and include molecular targeted therapy, immunotherapy, and small molecular therapy. Nevertheless, in recent years, accumulating evidence has indicated that small molecules, especially long noncoding RNAs (lncRNAs), are involved in the occurrence, development, and progression of GC, and their abundantly dysregulated expression has been identified in GC tissues and cell lines. Therefore, lncRNAs are considered easily detectable molecules and ideal biomarkers or target-specific agents for the future diagnosis or treatment of GC. In this review, we primarily discuss the status of GC, the role of lncRNAs in GC, and the emerging systemic treatments for GC.

CRISPR/Cas mediated epigenome editing for cancer therapy

The understanding of the relationship between epigenetic alterations, their effects on gene expression and the knowledge that these epigenetic alterations are reversible, have opened up new therapeutic pathways for treating various diseases, including cancer. This has led the research for a better understanding of the mechanism and pathways of carcinogenesis and provided the opportunity to develop the therapeutic approaches by targeting such pathways. Epi-drugs, DNA methyl transferase (DNMT) inhibitors and histone deacetylase (HDAC) inhibitors are the best examples of epigenetic therapies with clinical applicability. Moreover, precise genome editing technologies such as CRISPR/Cas has proven their efficacy in epigenome editing, including the alteration of epigenetic markers, such as DNA methylation or histone modification. The main disadvantage with DNA gene editing technologies is off-target DNA sequence alteration, which is not an issue with epigenetic editing. It is known that cancer is linked with epigenetic alteration, and thus CRISPR/Cas system shows potential for cancer therapy via epigenome editing. This review outlines the epigenetic therapeutic approach for cancer therapy using CRISPR/Cas, from the basic understanding of cancer epigenetics to potential applications of CRISPR/Cas in treating cancer.

LINC00488 stimulates the progression of esophageal cancer by targeting microRNA-485-5p

Esophageal cancer is the eighth most prevalent malignancy in the world and China has a high incidence of esophageal cancer. Previous studies have identified that LINC00488 is an oncogene; however, its role in esophageal cancer remains unclear. The present study detected the expression and biological functions of LINC00488 in the progression of esophageal cancer. LINC00488 levels in 45 esophageal cancer and matched paracancerous tissues were detected. The association between LINC00488 level, clinical indexes and overall survival rate of patients with esophageal cancer was analyzed. Using Cell Counting Kit-8, Transwell and wound healing assays, the influence of LINC00488 on the biological functions of OE19 and OE33 cells were assessed. The target gene of LINC00488, microRNA-485-5p (miRNA-485-5p), was predicted using bioinformatics databases. In addition, the role of miRNA-485-5p in the progression of esophageal cancer was evaluated using rescue experiments. LINC00488 was upregulated in esophageal cancer tissues and cell lines. A high level of LINC00488 was associated with lymphatic and distant metastasis and poor prognosis in patients with esophageal cancer. Silencing LINC00488 attenuated the viability, migration and wound healing of OE19 and OE33 cells. miRNA-485-5p was downregulated in esophageal cancer and low expression levels predicted a poor prognosis in these patients. In addition, miRNA-485-5p level was negatively correlated with that of LINC00488. Rescue experiments showed that knockdown of miRNA-485-5p reversed the attenuated proliferation and migration of esophageal cancer cells with LINC00488-knockdown. In conclusion, LINC00488 aggravated the malignant progression of esophageal cancer by targeting miRNA-485-5p.

Downregulation of LINC01021 by curcumin analog Da0324 inhibits gastric cancer progression through activation of P53

Curcumin is a safe, cost-effective natural agent with multiple targets that displays therapeutic potential in cancer. Recently, we reported a novel curcumin analog, Da0324, which exhibited significantly improved stability and anti-cancer activity. However, the molecular mechanism underlying the anti-cancer activity of Da0324 remains largely unknown. Long non-coding RNAs have been shown to play important roles in cancer development and progression and may be potential targets for cancer therapy. Here, we showed that Da0324 treatment down-regulated the expression of LINC01021 in gastric cancer cells. Da0324 treatment or knockdown of LINC01021 by antisense oligos significantly inhibited gastric cancer cell growth, and also up-regulated P53 expression and down-regulated Bcl-2 expression in vitro and in vivo. Furthermore, Da0324 treatment or knockdown of LINC01021 in gastric cancer cells suppressed cell migration, invasion and epithelial-mesenchymal transition (EMT), as well as induced apoptosis and autophagy. In addition, overexpression of LINC01021 promoted growth and EMT, inhibited P53 expression and increased Bcl-2 expression in gastric cancer cells. Finally, overexpression of LINC01021 reversed the anti-cancer effect of Da0324. Our findings indicate a novel anti-cancer mechanism for Da0324, and that LINC01021 might be a potential therapeutic target for the treatment of gastric cancer.

Long Non-coding RNA AK025387 Promotes Cell Migration and Invasion of Gastric Cancer

Gastric cancer is one of the most common cancers in the world, and long non-coding RNAs (lncRNAs) play a crucial role in proliferation, metastasis, and invasion of gastric cancer. However, there are very few researches focusing on the effects of lncRNAs on metastatic gastric cancer. In this research, we identify one kind of lncRNA, called AK025387, which is highly expressed in metastatic gastric cancer samples compared with non-metastatic gastric cancer samples. The expression of AK025387 is significantly positively correlated with lymph node metastasis. The in situ hybridization demonstrates that AK025387 is located in both nucleus and cytoplasm, but mostly in cytoplasm. AK025387 promotes gastric cancer cells migratory and invasive ability, but it inhibits apoptosis in vitro. Furthermore, AK025387 regulates Raf-1, mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK), and extracellular signal-regulated kinase (ERK) and is involved in mitogen-activated protein kinase (MAPK) signaling pathway to perform its biological functions. We conclude that AK025387 is highly expressed in metastatic gastric cancer, and its biological functions suggest the potential of AK025387 to be a biomarker of metastatic gastric cancer.

Long Noncoding RNA DLGAP1-AS1 Promotes the Aggressive Behavior of Gastric Cancer by Acting as a ceRNA for microRNA-628-5p and Raising Astrocyte Elevated Gene 1 Expression

Purpose

The long noncoding RNA DLGAP1 antisense RNA 1 (DLGAP1-AS1) plays well-defined roles in the malignant progression of hepatocellular carcinoma. The purpose of this study was to determine whether DLGAP1-AS1 affects the aggressive behavior of gastric cancer (GC).

Methods

DLGAP1-AS1 expression in GC tissue samples and cell lines was determined by reverse-transcription quantitative PCR. GC cell proliferation, apoptosis, migration, invasion, and tumor growth in vitro as well as in vivo were examined by the Cell Counting Kit-8 assay, flow-cytometric analysis, transwell migration and invasion assays, and xenograft model experiments, respectively.

Results

DLGAP1-AS1 was overexpressed in GC tissue samples and cell lines. Among patients with GC, the increased level of DLGAP1-AS1 correlated with tumor size, TNM stage, lymph node metastasis, distant metastasis, and shorter overall survival. The knockdown of DLGAP1-AS1 suppressed GC cell proliferation, migration, and invasion in vitro, as well as promoted cell apoptosis and hindered tumor growth in vivo. Mechanistically, DLGAP1-AS1 functioned as a competing endogenous RNA for microRNA-628-5p (miR-628-5p) in GC cells, thereby increasing the expression of the miR-628-5p target astrocyte elevated gene 1 (AEG-1). Functionally, the recovery of the miR-628-5p/AEG-1 axis output attenuated the effects of DLGAP1-AS1 knockdown in GC cells.

Conclusion

DLGAP1-AS1 is a pleiotropic oncogenic lncRNA in GC. DLGAP1-AS1 plays a pivotal part in the oncogenicity of GC in vitro and in vivo by regulating the miR-628-5p/AEG-1 axis. DLGAP1-AS1, miR-628-5p, and AEG-1 form a regulatory pathway to facilitate GC progression, suggesting this pathway as an effective target for the treatment of GC.

Recent Advances in Cancer Plasticity: Cellular Mechanisms, Surveillance Strategies, and Therapeutic Optimization

The processes of recurrence and metastasis, through which cancer relapses locally or spreads to distant sites in the body, accounts for more than 90% of cancer-related deaths. At present there are very few treatment options for patients at this stage of their disease. The main obstacle to successfully treat advanced cancer is the cells' ability to change in ways that make them resistant to treatment. Understanding the cellular mechanisms that mediate this cancer cell plasticity may lead to improved patient survival. Epigenetic reprogramming, together with tumor microenvironment, drives such dynamic mechanisms favoring tumor heterogeneity, and cancer cell plasticity. In addition, the development of new approaches that can report on cancer plasticity in their native environment have profound implications for studying cancer biology and monitoring tumor progression. We herein provide an overview of recent advancements in understanding the mechanisms regulating cell plasticity and current strategies for their monitoring and therapy management.

Long noncoding RNA LINC00339 promotes the oncogenicity of gastric cancer by regulating SRY-box 9 expression via sponging of microRNA-539

Differential expression of LINC00339 is involved in the malignancy of multiple human cancer types. Nonetheless, the expression profile, functions, and potential mechanisms of action of LINC00339 in gastric cancer are yet to be fully elucidated. This study aimed at measuring LINC00339 expression in gastric cancer and examining the prognostic significance of LINC00339 in patients with gastric cancer. The detailed functions of LINC00339 with regard to the aggressive characteristics of gastric cancer cells and the underlying molecular mechanisms were investigated. Here, we found that LINC00339 expression was aberrantly high in gastric cancer and significantly associated with lymph node metastasis, invasive depth, and TNM stage. Patients with gastric cancer in a LINC00339 high-expression group showed shorter overall survival than patients in a LINC00339 low-expression group. A knockdown of LINC00339 suppressed gastric cancer cell proliferation, migration, and invasion and induced apoptosis in vitro and slowed tumor growth in vivo. In terms of the mechanism, LINC00339 was found to act as a molecular sponge on microRNA-539 (miR-539). SRY-box 9 (SOX9) was confirmed as a direct target gene of miR-539 in gastric cancer cells. An miR-539 knockdown attenuated the effects of the LINC00339 knockdown on the malignant characteristics of gastric cancer cells. Overall, LINC00339 plays a critical role in the malignancy of gastric cancer by regulating SOX9 via sponging of miR‑539. Our findings highlight the importance of the LINC00339-miR-539-SOX9 pathway in gastric cancer pathogenesis and may point to novel targets for the diagnosis, prognosis, and/or treatment of gastric cancer.

M2 bone marrow-derived macrophage-derived exosomes shuffle microRNA-21 to accelerate immune escape of glioma by modulating PEG3

Background

Growing studies have focused on the role of microRNA-21 (miR-21) in glioma, thus our objective was to discuss the effect of M2 bone marrow-derived macrophage (BMDM)-derived exosomes (BMDM-Exos) shuffle miR-21 on biological functions of glioma cells by regulating paternally expressed gene 3 (PEG3).

Methods

Seventy-one cases of human glioma tissues and 30 cases of non-tumor normal brain tissues were collected and stored in liquid nitrogen. PEG3 and miR-21 expression in glioma tissues was tested. The fasting venous blood of glioma patients and healthy control was collected and centrifuged, and then the supernatant was stored at - 80 °C refrigerator. The contents of interferon (IFN)-γ and transforming growth factor-β1 (TGF-β1) in serum were tested by ELISA. Glioma cells and normal glial cells were cultured to screen the target cells for further in vitro experiments. BMDM-Exos was obtained by ultra-high speed centrifugation and then was identified. BMDM-Exos was co-cultured with U87 cells to detect the biological functions. The fasting venous blood of glioma patients was extracted and treated with ethylene diamine tetraacetic acid-K2 anti-freezing, and then CD8⁺T cells were isolated. CD8⁺T cells were co-cultured with U87 cells to detect the CD8⁺T proliferation, cell cytotoxic activity, U87 cell activity, as well as IFN-γ and TGF-β1 levels. Moreover, BALB/c-nu/nu mice was taken, and the human-nude mouse glioma orthotopic transplantation model was established with U87 cells, and then mice were grouped to test the trends in tumor growth. The brain of mice (fixed by 10% formaldehyde) was sliced to detect the expression of Ki67 and proliferating cell nuclear antigen (PCNA). The spleen of mice was taken to prepare single-cell suspension, and the percentage of T lymphocytes in spleen to CD8⁺T cells was detected.

Results

PEG3 expression was decreased and miR-21 expression was increased in glioma cells and tissues. Depleting miR-21 or restoring PEG3 suppressed growth, migration and invasion as well as accelerated apoptosis of glioma cells, also raised CD8⁺T proliferation, cell cytotoxic activity, and IFN-γ level as well as decreased U87 cell activity and TGF-β1 level. BMDM-Exos shuttle miR-21 promoted migration, proliferation and invasion as well as suppressed apoptosis of glioma cells by reducing PEG3. Exosomes enhanced the volume of tumor, Ki67 and PCNA expression, reduced the percentage of CD8⁺T cells in glioma mice.

Conclusion

BMDM-Exos shuffle miR-21 to facilitate invasion, proliferation and migration as well as inhibit apoptosis of glioma cells via inhibiting PEG3, furthermore, promoting immune escape of glioma cells.

Overexpression of long non-coding RNA RP11-363E7.4 inhibits proliferation and invasion in gastric cancer

LncRNA RP11‐363E7.4 has been shown to be downregulated in gastric cancer (GC), while the effect of lncRNA RP11‐363E7.4 on GC and its potential molecular mechanisms is unclear. The purpose of this study was to explore the functional role and underlying molecular mechanisms of lncRNA RP11‐363E7.4 involved in GC progress.To address the question, quantitative real‐time PCR assay was performed to confirm lncRNA RP11‐363E7.4 expression levels in GC tissues and cell lines. Cell proliferation, apoptosis, migration and invasion were estimated using Cell Counting Kit‐8, colony formation, scratch wound healing and Transwell assays. Potential molecular mechanisms were evaluated using western blot assay. The results showed that lncRNA RP11‐363E7.4 was significantly downregulated in GC cell lines and 82 paired tissues. The correlation between expression and clinicopathological features indicated that low expression of lncRNA RP11‐363E7.4 was associated with T stage (P = .010). Functional experiments showed that overexpression of lncRNA RP11‐363E7.4 prevented proliferation, migration, and invasion and induced apoptosis of GC cells. Western blot assay revealed that lncRNA RP11‐363E7.4 functioned via the p53, Bax/Bcl‐2, β‐catenin pathway. In summary, this study revealed that lncRNA RP11‐363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. Significance of the study:LncRNA RP11‐363E7.4 has been shown to be downregulated in GC, while the effect of lncRNA RP11‐363E7.4 on GC and its potential molecular mechanism is unclear. We revealed that lncRNA RP11‐363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. LncRNA RP11‐363E7.4 might become an attractive diagnostic and prognostic biomarker of GC and a promising target for GC treatment.

HIF-1α induced lncRNA LINC00511 accelerates the colorectal cancer proliferation through positive feedback loop

Long noncoding RNAs lncRNAs play an essential role in the epigenetic regulation of colorectal cancer CRC. However, the biological function of lncRNA Long Intergenic Noncoding RNA 00511 LINC00511 in the CRC is unclear. Here, present research found that LINC00511 was significantly up-regulated in the CRC tissue samples and cell lines. Consistently, LINC00011 overexpression was correlated with larger tumor size and advanced tumor stage. Functionally, LINC00511 promoted the proliferation and reduced the apoptosis of CRC cells in vitro, and LINC00511 knockdown repressed tumor growth in vivo. Mechanistically, hypoxia-inducible factor 1α (HIF-1α) bound the promoter region of LINC00511 to active tits transcription. Moreover, LINC00511 functioned as the miR-153-5p sponge in the cytoplasmic portion, and miR-153-5p also targeted the 3'-UTR of HIF-1α. In conclusion, this study identifies the roles of LINC00511 in CRC progression and uncovers the positive feedback loop of HIF-1α/LINC00511/miR-153-5p in CRC, providing a potential therapeutic target.

A Feedback Loop Regulation Of LINC01433 And YAP Promotes Malignant Behavior In Gastric Cancer Cells

Background

Gastric cancer (GC) is one of the most common cancers and the second leading cause of cancer-related death worldwide. Long noncoding RNAs (lncRNAs) are associated with GC development and progression. However, the functional roles and underlying mechanism of LINC01433 on GC progression remain elusive.

Methods

Firstly, the expression of LINC01433 was examined in 76 pairs of primary GC and corresponding adjacent non-tumorous tissues. Next, overexpression and knockdown experiments were conducted in GC cells to explore the effect of LINC01433 on the malignant behaviors of GC cells. Then, the interaction between LINC01433 and YAP was detected by RNA immunoprecipitation (RIP) and RNA pull-down assays.

Results

We found that LINC01433 was significantly upregulated in GC tissues and cell lines and correlated with poor prognosis. Through gain- and loss-of-function experiments, we demonstrated that LINC01433 promoted proliferation, migration, invasion and chemotherapy resistance in GC cells. Further mechanistic investigation revealed that LINC01433 could stabilize oncoprotein YAP through enhancing the interaction between deubiquitinase USP9X and YAP. LINC01433 decreased the phosphorylation of YAP via suppressing YAP-LATS1 association. Intriguingly, YAP directly bound to LINC01433 promoter region and activated its transcription. Thus, LINC01433 and YAP formed a positive feedback loop.

Conclusion

Collectively, our study demonstrates that the positive feedback loop between LINC01433 and YAP promotes GC progression, and implies that the LINC01433-YAP feedback loop may be a promising therapeutic target for GC treatment.

Overexpression of the Long Noncoding RNA FOXD2-AS1 Promotes Cisplatin Resistance in Esophageal Squamous Cell Carcinoma Through the miR-195/Akt/mTOR Axis

Emerging evidence has demonstrated that long noncoding RNAs (lncRNAs) mediate the development of esophageal squamous cell carcinoma (ESCC) via various pathophysiological pathways. This study explored the impact of the lncRNA FOXD2-AS1 on cisplatin resistance in ESCC and its possible mechanisms. Upregulation of FOXD2-AS was detected in patients with ESCC and ESCC cells that are resistant to cisplatin. In an in vitro assay, knockdown of FOXD2-AS1 noticeably inhibited cell invasion and growth, triggered cell death, and repressed the stimulation of the Akt/mTOR axis in cisplatin-resistant ESCC cells (TE-1/DDP). Conversely, the overexpression of FOXD2-AS1 remarkably increased cell invasion and growth, repressed cell death, and triggered the stimulation of the Akt/mTOR axis in TE-1/DDP cells. These findings, along with bioinformatics and validation tests, showed that FOXD2-AS1 targeted miR-195 by acting as a competing endogenous RNA. FOXD2-AS1/miR-195/Akt/mTOR axis plays a crucial role in resistance to cisplatin in ESCC cells, offering an innovative strategy to treat ESCC.

SNHG8 is upregulated in esophageal squamous cell carcinoma and directly sponges microRNA-411 to increase oncogenicity by upregulating KPNA2

Background

The long noncoding RNA, small nucleolar RNA host gene 8 (SNHG8), is upregulated in multiple human cancer types. However, whether SNHG8 is aberrantly expressed in esophageal squamous cell carcinoma (ESCC) and its biological functions have yet to be elucidated. Thus, we aimed to determine the expression status of SNHG8 in ESCC, explore the effects of SNHG8 on the oncogenicity of ESCC, and investigate the potential underlying mechanisms.

Methods

SNHG8 expression in ESCC tissues and cell lines was determined via reverse-transcription quantitative polymerase chain reaction. The actions of SNHG8 on the malignant characteristics of ESCC were explored using CCK-8 assay, flow-cytometric analysis, Transwell migration and invasion assays, and tumor xenografts in nude mice.

Results

SNHG8 expression was significantly higher in ESCC tissues and cell lines. High SNHG8 expression was revealed to closely correlate with primary tumor invasion depth, lymph node metastases, TNM stage, and worse overall survival among patients with ESCC. Functional investigation showed that ablation of SNHG8 notably restricted ESCC cell proliferation, migration, and invasion while inducing apoptosis in vitro and hindered tumor growth in vivo. In the meantime, SNHG8 acted as a molecular sponge of microRNA-411 (miR-411) in ESCC. Furthermore, miR-411 exerted a tumor-suppressive effect on ESCC cells, and karyopherin alpha 2 (KPNA2) turned out to be a direct target gene of miR-411. Restoring KPNA2 expression neutralized the inhibitory effects of miR-411 overexpression on the malignant behaviors of ESCC cells. Moreover, silencing of miR-411 abrogated the influence of SNHG8 downregulation in ESCC cells.

Conclusion

SNHG8 may play oncogenic roles in the malignancy of ESCC by sponging miR-411 to increase KPNA2 expression. The SNHG8–miR-411–KPNA2 pathway may be a novel target for the treatment of patients with ESCC and offer potential biomarkers for the diagnosis and prognosis of ESCC.

Long noncoding RNA SNHG16 silencing inhibits the aggressiveness of gastric cancer via upregulation of microRNA-628-3p and consequent decrease of NRP1

Background

MicroRNA-628-3p (miR-628) has been reported to play important roles in the progression of multiple human cancer types. Nonetheless, whether the expression profile of miR-628 is altered in gastric cancer remains unclear and whether its aberrant expression plays a crucial part in the aggressiveness of gastric cancer is yet to be determined. Therefore, in this study, we systematically investigated the involvement of miR-628 in gastric cancer progression.

Materials and methods

MiR-628 expression in gastric cancer tissues and cell lines were determined via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). A CCK-8 assay, flow-cytometric analysis, Transwell assays, and a xenograft model experiment were performed to evaluate the influence of miR-628 overexpression on gastric cancer cells. Notably, the mechanisms underlying the tumor-suppressive activity of miR-628 in gastric cancer cells were explored by bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blotting.

Results

MiR-628 expression was low in gastric cancer tissue samples and cell lines. The low expression of miR-628 was closely associated with the lymph node metastasis, invasive depth and TNM stage among patients with gastric cancer. Further clinical analysis indicated that patients with gastric cancer underexpressing miR-628 had a worse prognosis than did the patients with high miR-628 expression in the tumor. Overexpressed miR-628 restrained proliferation, migration, and invasion; induced apoptosis; and impaired tumor growth of gastric cancer cells. In addition, neuropilin 1 (NRP1) mRNA was validated as the direct target of miR-628 in gastric cancer. Long noncoding RNA small nucleolar RNA host gene 16 (SNHG16) was demonstrated to sponge miR-628 in gastric cancer. Moreover, miR-628 knockdown abrogated the influence of SNHG16 silencing on gastric cancer cells.

Conclusion

Our findings elucidate how the SNHG16–miR-628–NRP1 pathway serves as a regulatory network playing crucial roles in gastric cancer progression, suggesting that this pathway may be a novel target of anticancer therapy.

Long noncoding RNA CASC11 promotes osteosarcoma metastasis by suppressing degradation of snail mRNA

Osteosarcoma (OS) is the most common primary bone tumor in adolescents. Dysregulation of long noncoding RNAs (lncRNAs) is associated with the cancer progression, of which cancer susceptibility candidate 11 (CASC11) has been indicated as an oncogene in several human cancers. However, the underlying mechanisms by which CASC11 contributes to OS metastasis remain undetermined. Here, we found that CASC11 expression in OS tissues was markedly higher than that in noncancerous tissues. Clinical association analysis revealed that high CASC11 expression correlated with clinical stage, distant metastasis and poor prognosis of OS patients. Gain- and loss-of-function assays demonstrated that CASC11 promoted migration, invasion, epithelial-mesenchymal transition (EMT) and metastasis of OS cells in vitro and in vivo. CASC11 associated with the EMT inducer Snail mRNA and increased its stability. Association of CASC11 with Snail mRNA blocked the repressing effect of miR-122, miR-145, miR-211, miR-34a and miR-137 on Snail. Moreover, CASC11-specific siRNAs significantly inhibit tumor metastasis in vivo. Taken together, our findings suggest that CASC11 may be a candidate prognostic biomarker and a novel therapeutic target for OS.