miR-218 suppresses gastric cancer cell cycle progression through the CDK6/Cyclin D1/E2F1 axis in a feedback loop

Circular RNA circRNA_100349 functions as a miR-218-5p sponge for suppressing the cell proliferation of gastric cancer via regulation of IGF2 expression

BACKGROUND

Circular RNAs (circRNAs) hold critical importance due to their notable function in developing Gastric Cancer (GC), which is a malignancy with the third most frequent occurrence worldwide. The aim of this study was to see if circRNA_0044516 would control GC cell proliferation and establish more effective therapeutic strategies.

METHODS

In GC tissues or cells, quantitative Real‑Time Polymerase Chain Reaction (qRT-PCR) was employed for the detection of the expression of circRNA_100349, Insulin-like Growth Factor II (IGF2), and miR-218-5p. CCK-8 assays were employed to gauge the proliferation of cells. A luciferase reporter was employed to establish the relationship of circRNA_100349 or IGF2 with miR-218-5p.

RESULTS

CircRNA_100349 was observed to undergo upregulation in GC cell lines along with tissues. GC cell proliferation was prevented by downregulating circRNA_100349. MiR-149 was targeted by CircRNA_100349, and its downregulation increased the amount of miR-218-5p in GC cells. Simultaneously silencing circRNA_100349 decreased IGF2 expression via miR-218-5p, and thus suppressed GC cell proliferation. Furthermore, in nude mice, circRNA_100349 knockdown prevented the tumor development of GC cells.

CONCLUSIONS

The findings furnished evidence of the critical involvement of circRNA_100349 in GC and that its downregulation impedes GC cell proliferation via the miR-218-5p/IGF2 axis.

circE2F1-encoded peptide inhibits circadian machinery essential for nucleotide biosynthesis and tumor progression via repressing SPIB/E2F1 axis

Circadian clock dominates a variety of biological activities, while its roles and regulatory mechanisms in neuroblastoma (NB), a pediatric extracranial malignancy, still remain largely elusive. Herein, through comprehensive analyses of public datasets, E2F transcription factor 1 (E2F1) and its circular RNA (circE2F1)-encoded 99-amino acid peptide (E2F1-99aa) were identified as vital regulators of circadian machinery essential for purine and pyrimidine biosynthesis during NB progression. Mechanistically, through interaction with Spi-B transcription factor (SPIB), E2F1 was transactivated to up-regulate circadian machinery genes (CRY1 and TIMELESS), resulting in relief of CLOCK/BMAL1-repressed transcription of enzymes (DHODH, PAICS, or PPAT) essential for de novo purine and pyrimidine biosynthesis. The biogenesis of circE2F1 was repressed by eukaryotic translation initiation factor 4A3 (EIF4A3), while E2F1-99aa or its truncated peptide competitively bound to SPIB, leading to decrease in SPIB-E2F1 interaction, circadian machinery and nucleotide biosynthetic gene expression, purine or pyrimidine biosynthesis, tumorigenesis, and aggresiveness of NB cells. In clinical NB cases, high EIF4A3, E2F1 or SPIB expression was correlated with low survival possibility of patients, while lower circE2F1 or E2F1-99aa levels were associated with advanced stages and tumor progression. These results indicate that circE2F1-encoded peptide inhibits circadian machinery essential for nucleotide biosynthesis and tumor progression via repressing SPIB/E2F1 axis.

HK2 and LDHA upregulation mediate hexavalent chromium-induced carcinogenesis, cancer development and prognosis through miR-218 inhibition

Hexavalent chromium [Cr(VI)] is one of the most common environmental contaminants due to its tremendous industrial applications, but its effects and mechanism remain to be investigated. Our previous studies showed that Cr(VI) exposure caused malignant transformation and tumorigenesis. This study showed that glycolytic proteins HK2 and LDHA levels were statistically significant changed in blood samples of Cr(VI)-exposed workers and in Cr-T cells compared to the control subjects and parental cells. HK2 and LDHA knockdown inhibited cell proliferation and angiogenesis, and higher HK2 and LDHA expression levels are associated with advanced stages and poor prognosis of lung cancer. We found that miR-218 levels were significantly decreased and miR-218 directly targeted HK2 and LDHA for inhibiting their expression. Overexpression of miR-218 inhibited glucose consumption and lactate production in Cr-T cells. Further study found that miR-218 inhibited tumor growth and angiogenesis by decreasing HK2 and LDHA expression in vivo. MiR-218 levels were negatively correlated with HK2 and LDHA expression levels and cancer development in human lung and other cancers. These results demonstrated that miR-218/HK2/LDHA pathway is vital for regulating Cr(VI)-induced carcinogenesis and human cancer development.

Liver-derived extracellular vesicles from patients with hepatitis B virus-related acute-on-chronic liver failure impair hepatic regeneration by inhibiting on FGFR2 signaling via miR-218-5p

BACKGROUND

Impaired liver regeneration in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients is closely related to prognosis; however, the mechanisms are not yet defined. Liver-derived extracellular vesicles (EVs) may be involved in the dysregulation of liver regeneration. Clarifying the underlying mechanisms will improve the treatments for HBV-ACLF.

METHODS

EVs were isolated by ultracentrifugation from liver tissues of HBV-ACLF patients (ACLF_EVs) after liver transplantation, and their function was investigated in acute liver injury (ALI) mice and AML12 cells. Differentially expressed miRNAs (DE-miRNAs) were screened by deep miRNA sequencing. The lipid nanoparticle (LNP) system was applied as a carrier for the targeted delivery of miRNA inhibitors to improve its effect on liver regeneration.

RESULTS

ACLF_EVs inhibited hepatocyte proliferation and liver regeneration, with a critical role of miR-218-5p. Mechanistically, ACLF_EVs fused directly with target hepatocytes and transferred miR-218-5p into hepatocytes, acting by suppressing FGFR2 mRNA and inhibiting the activation of ERK1/2 signaling pathway. Reducing the level of miR-218-5p expression in the liver of ACLF mice partially restored liver regeneration ability.

CONCLUSION

The current data reveal the mechanism underlying impaired liver regeneration in HBV-ACLF that promotes the discovery of new therapeutic approaches.

PFDN2 promotes cell cycle progression via the hnRNPD-MYBL2 axis in gastric cancer

Gastric cancer (GC) is a major health burden worldwide, but our understanding of GC is limited, and the prognosis is poor. Novel therapeutic strategies and biomarkers are urgently needed to improve GC patient outcomes. Previously, we identified PFDN2 as a novel key gene in gastric cancer based on its differential expression between cancer and normal tissues. However, the role and underlying mechanisms of PFDN2 in GC remain elusive. In this article, we demonstrated that PFDN2 is highly expressed in GC and that upregulation of PFDN2 is associated with the progression of GC. We further found that PFDN2 could promote cell cycle progression by promoting MYBL2 expression. Mechanistically, we demonstrated that PFDN2 could upregulate MYBL2 expression by facilitating the nuclear translocation of hnRNPD, and thus promoting MYBL2 transcriptional program. In conclusion, we found that PFDN2 promotes cell cycle progression via the hnRNPD-MYBL2 axis and may serve as a potential biomarker and therapeutic target for GC.

Biological and therapeutic viewpoints towards role of miR-218 in human cancers: Revisiting molecular interactions and future clinical translations

Understanding the exact pathogenesis of cancer is difficult due to heterogenous nature of tumor cells and multiple factors that cause its initiation and development. Treatment of cancer is mainly based on surgical resection, chemotherapy, radiotherapy and their combination, while gene therapy has been emerged as a new kind of therapy for cancer. Post-transcriptional regulation of genes has been of interest in recent years and among various types of epigenetic factors that can modulate gene expression, short non-coding RNAs known as microRNAs (miRNAs) have obtained much attention. The stability of mRNA decreases by miRNAs to repress gene expression. miRNAs can regulate tumor malignancy and biological behavior of cancer cells and understanding their function in tumorigenesis can pave the way towards developing new therapeutics in future. One of the new emerging miRNAs in cancer therapy is miR-218 that increasing evidence highlights its anti-cancer activity, while a few studies demonstrate its oncogenic function. The miR-218 transfection is promising in reducing progression of tumor cells. miR-218 shows interactions with molecular mechanisms including apoptosis, autophagy, glycolysis and EMT, and the interaction is different. miR-218 induces apoptosis, while it suppresses glycolysis, cytoprotective autophagy and EMT. Low expression of miR-218 can result in development of chemoresistance and radio-resistance in tumor cells and direct targeting of miR-218 as a key player is promising in cancer therapy. LncRNAs and circRNAs are nonprotein coding transcripts that can regulate miR-218 expression in human cancers. Moreover, low expression level of miR-218 can be observed in human cancers such as brain, gastrointestinal and urological cancers that mediate poor prognosis and low survival rate.

Regulation of the Cell Cycle by ncRNAs Affects the Efficiency of CDK4/6 Inhibition

Cyclin-dependent kinases (CDKs) regulate cell division at multiple levels. Aberrant proliferation induced by abnormal cell cycle is a hallmark of cancer. Over the past few decades, several drugs that inhibit CDK activity have been created to stop the development of cancer cells. The third generation of selective CDK4/6 inhibition has proceeded into clinical trials for a range of cancers and is quickly becoming the backbone of contemporary cancer therapy. Non-coding RNAs, or ncRNAs, do not encode proteins. Many studies have demonstrated the involvement of ncRNAs in the regulation of the cell cycle and their abnormal expression in cancer. By interacting with important cell cycle regulators, preclinical studies have demonstrated that ncRNAs may decrease or increase the treatment outcome of CDK4/6 inhibition. As a result, cell cycle-associated ncRNAs may act as predictors of CDK4/6 inhibition efficacy and perhaps present novel candidates for tumor therapy and diagnosis.

Screening and identification of miR-181a-5p in oral squamous cell carcinoma and functional verification in vivo and in vitro

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a common malignant tumor associated with poor prognosis. MicroRNAs (miRNAs) play crucial regulatory roles in the cancer development. However, the role of miRNAs in OSCC development and progression is not well understood.

METHODS

We sought to establish a dynamic Chinese hamster OSCC animal model, construct miRNA differential expression profiles of its occurrence and development, predict its targets, and perform functional analysis and validation in vitro.

RESULTS

Using expression and functional analyses, the key candidate miRNA (miR-181a-5p) was selected for further functional research, and the expression of miR-181a-5p in OSCC tissues and cell lines was detected. Subsequently, transfection technology and a nude mouse tumorigenic model were used to explore potential molecular mechanisms. miR-181a-5p was significantly downregulated in human OSCC specimens and cell lines, and decreased miR-181a-5p expression was observed in multiple stages of the Chinese hamster OSCC animal model. Moreover, upregulated miR-181a-5p significantly inhibited OSCC cell proliferation, colony formation, invasion, and migration; blocked the cell cycle; and promoted apoptosis. BCL2 was identified as a target of miR-181a-5p. BCL2 may interact with apoptosis- (BAX), invasion- and migration- (TIMP1, MMP2, and MMP9), and cell cycle-related genes (KI67, E2F1, CYCLIND1, and CDK6) to further regulate biological behavior. Tumor xenograft analysis indicated that tumor growth was significantly inhibited in the high miR-181a-5p expression group.

CONCLUSION

Our findings indicate that miR-181a-5p can be used as a potential biomarker and provide a novel animal model for mechanistic research on oral cancer.

MiR-218-5p/EGFR Signaling in Arsenic-Induced Carcinogenesis

BACKGROUND

Arsenic is a well-known carcinogen inducing lung, skin, bladder, and liver cancer. Abnormal epidermal growth factor receptor (EGFR) expression is common in lung cancer; it is involved in cancer initiation, development, metastasis, and treatment resistance. However, the underlying mechanism for arsenic-inducing EGFR upregulation remains unclear.

METHODS

RT-PCR and immunoblotting assays were used to detect the levels of miR-218-5p and EGFR expression. The Luciferase assay was used to test the transcriptional activity of EGFR mediated by miR-218-5p. Cell proliferation, colony formation, wound healing, migration assays, tube formation assays, and tumor growth assays were used to study the function of miR-218-5p/EGFR signaling.

RESULTS

EGFR and miR-218-5p were dramatically upregulated and downregulated in arsenic-induced transformed (As-T) cells, respectively. MiR-218-5p acted as a tumor suppressor to inhibit cell proliferation, migration, colony formation, tube formation, tumor growth, and angiogenesis. Furthermore, miR-218-5p directly targeted EGFR by binding to its 3'-untranslated region (UTR). Finally, miR-218-5p exerted its antitumor effect by inhibiting its direct target, EGFR.

CONCLUSION

Our study highlights the vital role of the miR-218-5p/EGFR signaling pathway in arsenic-induced carcinogenesis and angiogenesis, which may be helpful for the treatment of lung cancer induced by chronic arsenic exposure in the future.

HuR Promotes the Progression of Gastric Cancer through Mediating CDC5L Expression

Methods

We performed qRT-PCR, cell cycle assay, cell migration, and mouse transplantation model analysis in our experiments. It has been clarified that HuR and microRNAs (miRNAs) have important interplays in the regulation of tumor progression.

Results

This study found microRNA-133b (miR-133b), as a HuR-sponged miRNA in GC cells. Downregulation of HuR can promote the expression of miR-133b and further affect the downstream cyclin CDC5L. The expressions of miR-133b were slightly lower in GC tissues than adjacent normal tissues.

Conclusion

Our studies suggest that HuR and miR-133b are involved in the development and pathological process of GC cells.

hsa-miR-875-5p inhibits tumorigenesis and suppresses TGF-β signalling by targeting USF2 in gastric cancer

Background

Gastric cancer (GC) is one of the most common malignancies, and an increasing number of studies have shown that its pathogenesis is regulated by various miRNAs. In this study, we investigated the role of miR-875-5p in GC.

Methods

The expression of miR-875-5p was detected in human GC specimens and cell lines by miRNA qRT–PCR. The effect of miR-875-5p on GC proliferation was determined by Cell Counting Kit-8 (CCK-8) proliferation and 5-ethynyl-2′-deoxyuridine (EdU) assays. Migration and invasion were examined by transwell migration and invasion assays as well as wound healing assays. The interaction between miR-875-5p and its target gene upstream stimulatory factor 2(USF2) was verified by dual luciferase reporter assays. The effects of miR-875-5p in vivo were studied in xenograft nude mouse models. Related proteins were detected by western blot.

Results

The results showed that miR-875-5p inhibited the proliferation, migration and invasion of GC cells in vitro and inhibited tumorigenesis in vivo. USF2 was proved to be a direct target of miR-875-5p. Knockdown of USF2 partially counteracted the effects of miR-875-5p inhibitor. Overexpression of miR-875-5p could inhibit proliferation, migration and invasion and suppress the TGF-β signalling pathway by downregulating USF2.

Conclusions

MiR-875-5p can inhibit the progression of GC by directly targeting USF2. And in the future, miR-875-5p is expected to be a potential target for GC diagnosis and treatment.

NDUFC1 Is Upregulated in Gastric Cancer and Regulates Cell Proliferation, Apoptosis, Cycle and Migration

Gastric cancer is one of the most common primary tumors of the digestive system. NADH: ubiquinone oxidoreductase subunit C1 (NDUFC1), which is an accessory subunit of the NADH dehydrogenase (complex I), is responsible for the transportation of electrons from NADH to the respiratory chain essential for the oxidative phosphorylation. However, little is known about the roles of NDUFC1 in carcinogenesis. In this study, NDUFC1 protein level in NSCLC tissues was tested by immunohistochemistry (IHC) staining. NDUFC1 mRNA level in gastric cancer cell lines was determined by qRT-PCR. MGC-803 and SGC-7901 cells were transfected with shNDUFC1 lentivirus designed to silence NDUFC1. MTT assay, CCK8 assay, wound healing assay and transwell migration assay were conducted. Cell cycle and apoptosis were detected by flow cytometry. In vivo experiments were performed using nude mice. The results indicated that overexpressed NDUFC1 in gastric cancer was related to more serious tumor infiltrates, a higher risk of lymphatic metastasis, a higher proportion of positive lymph nodes, and a more advanced tumor stage. Compared with shCtrl groups, MGC-803 and SGC-7901 of shNDUFC1 groups had lower abilities of proliferation and migration, higher levels of apoptosis. NDUFC1 knockdown also inhibited SGC-7901 cell growth in vivo and suppressed Ki67 expression in xenograft tumors. More importantly, we found that NDUFC1 downregulation made the levels of P-Akt, P-mTOR, CCND1, CDK6, PIK3CA, Bcl-2, Survivin, and XIAP decreased, and that PI3K/AKT signaling pathway agonist SC79 rescued the inhibitory effects on cell proliferation and migration, reversed the promoted effects on cell apoptosis caused by NDUFC1 knockdown. More importantly, compared with NDUFC1 knockdown group, the expression of P-Akt, Bcl-2, Survivin, and XIAP was raised in shNDUFC1 + SC79 group. Thus, our suspicion was that NDUFC1 exacerbates NSCLC progression via PI3K/Akt pathway. Taken together, our study indicated that targeting NDUFC1 could open innovative perspectives for new multi-targeting approaches in the treatment of gastric cancer.

Long non-coding RNA HOXA-AS3 promotes cell proliferation of oral squamous cell carcinoma through sponging microRNA miR-218-5p

Increasing evidence demonstrated long non-coding RNAs (lncRNAs) play important roles in the occurrence and development of oral squamous cell carcinoma (OSCC). This study aimed to explore the role and molecular mechanism of lncRNA HOXA-AS3 in the progression of OSCC. Here, we found that the expression of lncRNA HOXA-AS3 was upregulated in OSCC tissues and cell lines compared with the para-cancerous tissues and normal human oral keratinocyte (NHOK), respectively. Inhibition of HOXA-AS3 significantly inhibited the proliferation and colony formation of OSCC cells. Further, the luciferase reporter assay showed that HOXA-AS3 was directly bound to miR-218-5p. Moreover, the expression of miR-218-5p was negatively regulated by HOXA-AS3, and miR-218-5p could inhibit the expression of collagen type I alpha1 (COL1A1) and lysophosphatidylcholine acyltransferase 1 (LPCAT1). In addition, silencing miR-218-5p reversed the inhibitory effect of HOXA-AS3 knockdown on the proliferative potential of OSCC cells. In summary, our study illustrated that HOXA-AS3 promoted cancer cell proliferation in OSCC, possibly by sponging miR-218-5p for the first time, which provides a new target or a potential diagnostic biomarker for OSCC.

Rab6c is a new target of miR‑218 that can promote the progression of bladder cancer

Bladder cancer has high morbidity and mortality rates among the male genitourinary system tumor types. MicroRNA‑218 (miR‑218) is associated with the development of a variety of cancer types, including bladder cancer. Rab6c is a member of the Rab family and is involved in drug resistance in MCF7 cells. The aim of the present study was to clarify the relationship between Rab6c and miR‑218 in bladder cancer cell lines. In this study, the expression levels of miR‑218 and Rab6c were evaluated via reverse transcription‑quantitative PCR and western blotting, respectively. The association between Rab6c and miR‑218 was recognized via TargetScan analysis and dual luciferase reporter gene detection. Cell proliferation was analyzed using Cell Counting Kit‑8 and colony formation assays, and the invasive ability was measured via Transwell assays. Rab6c was highly expressed in bladder cancer, while miR‑218 had abnormally low expression in bladder cancer. In addition, there was a mutual regulation between Rab6c and miR‑218 in bladder cancer. It was found that overexpression of Rab6c significantly enhanced the proliferation, colony formation and invasion of T24 and EJ cells. Furthermore, miR‑218 overexpression blocked the promoting effects of Rab6c on the malignant behavior of bladder cancer cells. Thus, Rab6c promotes the proliferation and invasion of bladder cancer cells, while miR‑218 has the opposite effect, which may provide a novel insight for the treatment of bladder cancer.

miR-486 Promotes the Invasion and Cell Cycle Progression of Ovarian Cancer Cells by Targeting CADM1

Objective

To explore the role and possible underlying mechanism of miR-486 in ovarian cancer (OC) cells.

Methods

The expression of miR-486 and CADM1 was detected by qRT-PCR in OC tissues and adjacent nontumor tissues and OC cell lines. The dual-luciferase reporter gene system was used to determine the targeting relationship between miR-486 and CADM1. CCK-8, colony formation assay, Transwell, and flow cytometry were performed to detect cell proliferation, cell invasion, cell cycle progression, and the apoptotic cell death, respectively. Western blot was carried out to detect the expression of CADM1 protein and the proteins associated with cell cycle progression.

Results

miR-486 was significantly upregulated in OC tissues and cells, while CADM1 expression was significantly downregulated. Dual-luciferase reporter assays further confirmed that CADM1 was a target gene of miR-486. Interference with miR-486 could inhibit the proliferation and invasion and promoted the apoptosis of SKOV3 cells. Knocking down both miR-486 and CADM1 significantly increased the SKOV3 cell proliferation, invasion, and the number of cells transitioning from the G0/G1 phase into the S phase of cell cycle and reduced the cellular apoptosis. Western blot analysis revealed that the expression of cell cycle progression-related proteins (CyclinD1, CyclinE, and CDK6) was significantly reduced, and the p21 expression was increased when interfering with both miR-486 and CADM1 expression.

Conclusion

Our results suggested that miR-486 could act as a tumor promoter by targeting CADM1 and be a potential therapeutic target for the treatment of OC.

miR-218-5p inhibits the malignant progression of glioma via targeting TCF12

Several studies have shown the ability of transcription factor 12 (TCF12) to promote tumor malignant progression, but its function in glioma cells has not been fully elucidated. In this study, we analyzed the data from TCGA by bioinformatics and found that in glioma tissue, TCF12 was conspicuously highly expressed while miR-218-5p was significantly low-expressed. The downregulation of miR-218-5p was correlated with adverse prognosis in patients with glioma. miR-218-5p was found to be negatively associated with TCF12 by Pearson correlation analysis, and dual luciferase assay was employed to verify that miR-218-5p and TCF12 had a targeting relationship. qRT-PCR and Western blot assays were used to verify that the expression of TCF12 was regulated by its upstream regulator miR-218-5p. Moreover, cell experiments validated that overexpressed TCF12 could promote the proliferation, migration, and invasion of glioma cells and inhibit their apoptosis, whereas overexpressing miR-218-5p at the same time could reverse this phenomenon. Our study demonstrates the regulatory mechanism of the miR-218-5p/TCF12 axis in gliomas, which lays a foundation for searching for new therapeutic approaches for glioma.

N6-Methyladenosine Associated Silencing of miR-193b Promotes Cervical Cancer Aggressiveness by Targeting CCND1

Objective

Cervical cancer is a frequently encountered gynecological malignancy as a major contributor to cancer-related deaths in women. This study focuses on how miR-193b promotes cervical cancer aggressiveness as well as the role of m⁶A in miR-193b silencing.

Methods

Cervical cancer samples and the matching adjacent normal cervical tissues were used to determine the significance of miR-193b in cervical cancer. The CCK-8 assay, cell cycle analysis, qRT-PCR, Western blot assay, IHC, RIP, and xenograft models were utilized to explore the impact of miR-193b in cervical cancer and how m⁶A regulates miR-193b expression. Luciferase reporter assays, qRT-PCR, and Western blotting were enlisted to study the interaction between miR-193b and CCND1.

Results

Our study suggested that lower miR-193b expressions were strongly linked to more advanced cervical cancer stages and the presence of deeper stromal invasion. miR-193b functions as a tumor suppressor that is regulated by m⁶A methylation in cervical tumors. METTL3 modulates miR-193b mature process in an m⁶A-dependent manner. Reintroduction of miR-193b profoundly inhibits tumorigenesis of cervical cancer cells both in vivo and in vitro through CCND1 targeting.

Conclusions

m⁶A associated downregulation of miR-193b promotes cervical cancer aggressiveness by targeting CCND1.

LINC01436 Inhibited miR-585-3p Expression and Upregulated MAPK1 Expression to Promote Gastric Cancer Progression

BACKGROUND

Gastric cancer (GC) is a prevalent type of digestion system malignancies. Dysregulation of long non-coding RNAs (lncRNAs) has been proven to be prognostic factors and biological regulators in human cancers.

AIMS

The current study aimed to explore the role of long intergenic non-protein coding RNA 1436 (LINC01436) and its underlying mechanism in the progression of GC.

METHODS

RT-qPCR was conducted to measure RNA expression. Western blot was used for exploration of protein level. CCK-8, caspase-3 activity, and transwell assays were applied to evaluate the proliferative, apoptotic, and migratory abilities of GC cells, respectively. Mechanical experiments were used to probe the molecular interplay between genes.

RESULTS

High LINC01436 level suggested low overall survival in GC patients, and LINC01436 was highly expressed in GC tissues and cells. Besides, LINC01436 knockdown hampered cell proliferation and migration, while facilitated cell apoptosis. Mechanistically, LINC01436 upregulated mitogen-activated protein kinase 1 (MAPK1) expression by competitively binding with miR-585-3p and inhibiting miR-585-3p expression. Furthermore, LINC01436 negatively regulated miR-585-3p expression by enhancing the zeste 2 polycomb repressive complex 2 subunit (EZH2)-induced trimethylation of histone H3 at lysine 27 (H3K27me3) on miR-585-3p promoter. Final rescue assays revealed that overexpression of MAPK1 could rescue the suppressive influence of LINC01436 depletion on GC progression.

CONCLUSIONS

LINC01436 epigenetically silences miR-585-3p and acts as miR-585-3p to upregulate MAPK1 expression and promote GC progression.

High miR-3650 expression in nasopharyngeal carcinoma and its clinical prognostic values

BACKGROUND

A recent study has reported that miR-3650 expression was significant reduced in hepatocellular carcinoma and predicted poor prognosis. However, the role of miR-3650 in nasopharyngeal carcinoma (NPC) remains indefinite.

METHODS

Total 140 cases of NPCs were included in this study. The expression of miR-3650 was determined in NPC tissues and adjacent nontumor tissues using qRT-PCR. Then the relationship between miR-3650 expression and clinicopathological features as well as survival were analyzed.

RESULTS

The expression of miR-3650 was significant higher in NPC tissues than that in adjacent nontumor tissues (P <  0.001). High expression of miR-3650 was significant correlated with tumor progression and distant metastasis of NPC patients. And patients with high miR-3650 expression have much worse 5-year overall survival (OS) and 5-year progression-free survival (PFS) than those with low expression (all P <  0.0001). Furthermore, Cox regression analysis showed that miR-3650 was an independent risk predictor for OS and PFS in NPC patients (all P =  0.000).

CONCLUSION

Our results demonstrated for the first time that miR-3650 was markedly upregulated in NPC tissues and positively associated with tumor progression and poor survival, suggesting that miR-3650 may be a potential novel prognostic biomarker and therapeutic target for NPC patients.

The Role of Extracellular Vesicles in Mediating Resistance to Anticancer Therapies

Although advances in targeted therapies have driven great progress in cancer treatment and outcomes, drug resistance remains a major obstacle to improving patient survival. Several mechanisms are involved in developing resistance to both conventional chemotherapy and molecularly targeted therapies, including drug efflux, secondary mutations, compensatory genetic alterations occurring upstream or downstream of a drug target, oncogenic bypass, drug activation and inactivation, and DNA damage repair. Extracellular vesicles (EVs) are membrane-bound lipid bilayer vesicles that are involved in cell-cell communication and regulating biological processes. EVs derived from cancer cells play critical roles in tumor progression, metastasis, and drug resistance by delivering protein and genetic material to cells of the tumor microenvironment. Understanding the biochemical and genetic mechanisms underlying drug resistance will aid in the development of new therapeutic strategies. Herein, we review the role of EVs as mediators of drug resistance in the context of cancer.

G protein gamma 7 suppresses progression of lung adenocarcinoma by inhibiting E2F transcription factor 1

G protein gamma 7 (GNG7) has been found to be aberrantly expressed in some kinds of malignant tumors. In this study, we mainly discuss the antitumor role of it in lung adenocarcinoma (LUAD) cells. Protein levels of GNG7 in LUAD tissues were measured by western blot and immunohistochemical analysis. Cell proliferation, invasion and migration were detected by CCK-8 assay, 5-ethynyl-2'-deoxyuridine (EdU), and Transwell assay. In our study, GNG7 was down-regulated in LUAD, which significantly correlated with survival of LUAD patients. Functional experiments revealed that GNG7 significantly inhibited LUAD cell proliferation, migration, and invasion in vitro and E2F1 overexpression reversed these properties. GNG7 suppressed xenograft tumorigenesis in nude mice models in vivo. In conclusion, GNG7 functions as a tumor suppressor in LUAD cells through inhibiting E2F1.

YY1-modulated long non-coding RNA SNHG12 promotes gastric cancer metastasis by activating the miR-218-5p/YWHAZ axis

Long non-coding RNA (lncRNA) small nucleolar RNA host gene 12 (SNHG12) plays important roles in the pathogenesis and progression of cancers. However, the role of SNHG12 in the metastasis of gastric cancer (GC) has not yet been thoroughly investigated. In the present study, we demonstrated that SNHG12 was upregulated in GC tissues and cell lines. In addition, the expression level of SNHG12 in GC samples was significantly related to tumor invasion depth, TNM stage and lymph node metastasis and was associated with disease-free survival (DFS) and overall survival (OS) in GC patients. In vivo and in vitro assays indicated that SNHG12 promotes GC metastasis and epithelial-mesenchymal transition (EMT). Bioinformatics and mechanistic analyses revealed that SNHG12 can directly target miR-218-5p to regulate YWHAZ mRNA, forming an SNHG12/miR-218-5p/YWHAZ axis and decreasing the ubiquitination of β-catenin. In addition, SNHG12 stabilizes CTNNB1 mRNA by binding with HuR, thus activating the β-catenin signaling pathway. Further analysis also revealed that the transcription factor YY1 negatively modulates SNHG12 transcription. In conclusion, SNHG12 is a potential prognostic marker and therapeutic target for GC. Negatively modulated by YY1, SNHG12 promotes GC metastasis and EMT by regulating the miR-218-5p/YWHAZ axis and stabilizing CTNNB1 via activation of the β-catenin signaling pathway.

miR-218-2 regulates cognitive functions in the hippocampus through complement component 3-dependent modulation of synaptic vesicle release

microRNA-218 (miR-218) has been linked to several cognition related neurodegenerative and neuropsychiatric disorders. However, whether miR-218 plays a direct role in cognitive functions remains unknown. Here, using the miR-218 knockout (KO) mouse model and the sponge/overexpression approaches, we showed that miR-218-2 but not miR-218-1 could bidirectionally regulate the contextual and spatial memory in the mice. Furthermore, miR-218-2 deficiency induced deficits in the morphology and presynaptic neurotransmitter release in the hippocampus to impair the long term potentiation. Combining the RNA sequencing analysis and luciferase reporter assay, we identified complement component 3 (C3) as a main target gene of miR-218 in the hippocampus to regulate the presynaptic functions. Finally, we showed that restoring the C3 activity in the miR-218-2 KO mice could rescue the synaptic and learning deficits. Therefore, miR-218-2 played an important role in the cognitive functions of mice through C3, which can be a mechanism for the defective cognition of miR-218 related neuronal disorders.

The Functional Role of Long Non-coding RNA UCA1 in Human Multiple Cancers: a Review Study

In various cancers, high-grade tumor and poor survival rate in patients with upregulated lncRNAs UCA1 have been confirmed. Urothelial carcinoma associated 1 (UCA1) is an oncogenic non-coding RNA with a length of more than 200 nucleotides. The UCA1 regulate critical biological processes that are involved in cancer progression, including cancer cell growth, invasion, migration, metastasis, and angiogenesis. So It should not surprise that UCA1 overexpresses in variety of cancers type, including pancreatic cancer, ovarian cancer, gastric cancer, colorectal cancer, breast cancer, prostate cancer, endometrial cancer, cervical cancer, bladder cancer, adrenal cancer, hypopharyngeal cancer, oral cancer, gallbladder cancer, nasopharyngeal cancer, laryngeal cancer, osteosarcoma, esophageal squamous cell carcinoma, renal cell carcinoma, cholangiocarcinoma, leukemia, glioma, thyroid cancer, medulloblastoma, hepatocellular carcinoma and multiple myeloma. In this article, we review the biological function and regulatory mechanism of UCA1 in several cancers and also, we will discuss the potential of its as cancer biomarker and cancer treatment.

LncRNA NKX2-1-AS1 promotes tumor progression and angiogenesis via upregulation of SERPINE1 expression and activation of the VEGFR-2 signaling pathway in gastric cancer

Long noncoding RNAs (lncRNAs) can compete with endogenous RNAs to modulate the gene expression and contribute to oncogenesis and tumor metastasis. lncRNA NKX2-1-AS1 (NKX2-1 antisense RNA 1) plays a pivotal role in cancer progression and metastasis; however, the contribution of aberrant expression of NKX2-1-AS1 and the mechanism by which it functions as a competing endogenous RNA (ceRNA) in gastric cancer (GC) remains elusive. NKX2-1-AS1 expression was detected in paired tumor and nontumor tissues of 178 GC patients by quantitative reverse transcription PCR (qRT-PCR). Using loss-of-function and gain-of-function experiments, the biological functions of NKX2-1-AS1 were evaluated both in vitro and in vivo. Further, to assess that NKX2-1-AS1 regulates angiogenic processes, tube formation and co-culture assays were performed. RNA binding protein immunoprecipitation (RIP) assay, a dual-luciferase reporter assay, quantitative PCR, Western blot, and fluorescence in situ hybridization (FISH) assays were performed to determine the potential molecular mechanism underlying this ceRNA. The results indicated that NKX2-1-AS1 expression was upregulated in GC cell lines and tumor tissues. Overexpression of NKX2-1-AS1 was significantly associated with tumor progression and enhanced angiogenesis. Functionally, NKX2-1-AS1 overexpression promoted GC cell proliferation, metastasis, invasion, and angiogenesis, while NKX2-1-AS1 knockdown restored these effects, both in vitro and in vivo. RIP and dual-luciferase assays revealed that the microRNA miR-145-5p is a direct target of NKX2-1-AS1 and that NKX2-1-AS1 serves as a ceRNA to sponge miRNA and regulate angiogenesis in GC. Moreover, serpin family E member 1 (SERPINE1) is an explicit target for miR-145-5p; besides, the NKX2-1-AS1/miR-145-5p axis induces the translation of SERPINE1, thus activating the VEGFR-2 signaling pathway to promote tumor progression and angiogenesis. NKX2-1-AS1 overexpression is associated with enhanced tumor cell proliferation, angiogenesis, and poor prognosis in GC. Collectively, NKX2-1-AS1 functions as a ceRNA to miR-145-5p and promotes tumor progression and angiogenesis by activating the VEGFR-2 signaling pathway via SERPINE1.

CDC37L1 acts as a suppressor of migration and proliferation in gastric cancer by down-regulating CDK6

The co-chaperone protein CDC37 (Cell division cycle 37) is well known to regulate multiple protein kinases and involved in tumor progression. However to date, little is known about its analogue CDC37L1 (Cell division cycle 37 like 1) in tumorigenesis. This study aimed to explore the expression and function of CDC37L1 in gastric cancer (GC). The immunohistochemical staining in a tissue microarray showed a weak expression of CDC37L1 in high grade GC tissues compared with low grade tissues. Consistently, data from online database analysis demonstrated that CDC37L1 level was decreased in stage 4 patients and low expression of CDC37L1 indicated a poor prognosis. Functional studies revealed that CDC37L1 could inhibit GC cell proliferation and migration in CCK8, EdU incorporation, colony formation and transwell assays. In the meantime, CDC37L1 also inhibited the tumorigenicity of GC cells in nude mice. Mechanistically, we found that CDC37L1 had an impact on CDK6 protein expression by western blotting. Palbociclib, a specific CDK4/6 inhibitor, was discovered to block the rapid growth phenotype of GC cells induced by CDC37L1 silencing. Taken together, these findings unveiled a tumor-suppressive role of CDC37L1 in GC, and CDK6 may act as a downstream effector in this process.

Hedgehog signaling in gastrointestinal carcinogenesis and the gastrointestinal tumor microenvironment

The Hedgehog (HH) signaling pathway plays important roles in gastrointestinal carcinogenesis and the gastrointestinal tumor microenvironment (TME). Aberrant HH signaling activation may accelerate the growth of gastrointestinal tumors and lead to tumor immune tolerance and drug resistance. The interaction between HH signaling and the TME is intimately involved in these processes, for example, tumor growth, tumor immune tolerance, inflammation, and drug resistance. Evidence indicates that inflammatory factors in the TME, such as interleukin 6 (IL-6) and interferon-γ (IFN-γ), macrophages, and T cell-dependent immune responses, play a vital role in tumor growth by affecting the HH signaling pathway. Moreover, inhibition of proliferating cancer-associated fibroblasts (CAFs) and inflammatory factors can normalize the TME by suppressing HH signaling. Furthermore, aberrant HH signaling activation is favorable to both the proliferation of cancer stem cells (CSCs) and the drug resistance of gastrointestinal tumors. This review discusses the current understanding of the role and mechanism of aberrant HH signaling activation in gastrointestinal carcinogenesis, the gastrointestinal TME, tumor immune tolerance and drug resistance and highlights the underlying therapeutic opportunities.

Sesamin induces cell cycle arrest and apoptosis through p38/C-Jun N-terminal kinase mitogen-activated protein kinase pathways in human colorectal cancer cells

Sesamin, a lignan compound, exhibits a variety of biological activities and possesses potent anticancer properties on some human cancers. However, its effect on human colorectal cancer (CRC) remains to be elucidated. To investigate the effects of sesamin on CRC cells and further to explore the mechanisms, cell viability, cell cycle and apoptosis assays were performed in this study. We found that sesamin had a selective antiproliferation of CRC cell line HCT116 in a dose- and time-dependent manner, but no obvious effect on human normal colorectal mucosa epithelial cell FHC. Further study showed that sesamin-induced cell cycle arrest and decreased the expression of Cyclin D1 significantly and dose-dependently in HCT116 cells. Moreover, sesamin dose-dependently triggered apoptosis of HCT116 but not FHC, and promoted the expression levels of proapoptotic biomarkers Bax, cleaved caspase-3 and cleaved PARP-1 and inhibited the expression of antiapoptotic biomarker Bcl-2. Western blot analysis was used to reveal the possible signaling pathways, and we found that sesamin upregulated the phosphorylation expression levels of C-Jun N-terminal kinase (JNK) and p38 except ERK1/2 in a dose-dependent way in both HCT116 and another CRC cell line SW480. Moreover, we found that the apoptosis effect induced by sesamin was partially eliminated by inhibiting JNK or p38 activation. Finally, we showed that sesamin effectively reduced the growth of xenograft tumors derived from cell lines with limited toxicity. Taken together, the potential ability of sesamin to induce cell cycle arrest and apoptosis was shown to be via the p38 and JNK mitogen-activated protein kinase signaling pathways, which may be one of the mechanisms of the anticancer activity of this low-toxic agent.

Development and clinical validation of a 3-miRNA signature to predict prognosis of gastric cancer

Aims

Identification of miRNA signature to predict the prognosis of gastric cancer (GC) patients by integrating bioinformatics and experimental validation.

Methods

The miRNA expression profile and clinical data of GC were collected. The univariable and LASSO-Cox regression were used to construct the risk signature. The receiver operating characteristic (ROC) curve analysis confirmed the good performance of the prognostic model.

Results

A 3-miRNA prognostic signature was constructed, which included hsa-miR-126-3p, hsa-miR-143-5p, and hsa-miR-1275. A nomogram, including the prognostic signature to predict the overall survival, was established, and internal validation in the The Cancer Genome Atlas (TCGA) cohort was performed. We found that compared with the traditional pathological stage, the nomogram was the best at predicting the prognosis.

Conclusions

The predictive model and the nomogram will enable patients with GC to be more accurately managed in clinical practice.

LncRNA PCGEM1 contributes to malignant behaviors of glioma by regulating miR-539-5p/CDK6 axis

Background: Glioma, one of the most prevalent and aggressive cancers, is regulated by long noncoding RNAs (lncRNAs). This study aims to research the functional mechanism of lncRNA PCGEM1 involved in glioma progression.

Methods: Expression levels of PCGEM1, miR-539-5p and CDK6 were analyzed by qRT-PCR in NHA, U251, U87, and LN229 cells or glioma tissues. shRNAs were used to knock down PCGEM1 in U251 and LN229 cells. Kaplan-Meier curve and log rank test were utilized to examine survival rate. CCK8 (Cell Counting Kit-8) assay, colony formation assay and EdU staining were conducted to detect cell proliferation. Transwell assay was performed to evaluate cell migration and invasion. Luciferase reporter assay was conducted to assess RNA interaction between PCGEM1 and miR-539-5p. Nude mice were used for tumor xenograft assay.

Results: LncRNA PCGEM1 was upregulated in glioma tissues and tumor cell lines. PCGEM1 upregulation predicted unsatisfactory prognosis. PCGEM1 knockdown inhibited proliferation, colony formation, migration and invasion. PCGEM1 knockdown delayed tumor growth in vivo. PCGEM1 played as a competing endogenous RNA (ceRNA) for miR-539-5p to promote CDK6 expression. MiR-539-5p mimics repressed glioma progression while CDK6 overexpression reversed the roles of PCGEM1 knockdown.

Conclusion: PCGEM1 knockdown suppressed glioma progression through sponging miR-539-5p and regulating CDK6 expression, implying PCGEM1 as a potential therapeutic target.

Potential Role of miRNAs in the Acquisition of Chemoresistance in Neuroblastoma

Neuroblastoma (NB) accounts for about 8–10% of pediatric cancers, and the main causes of death are the presence of metastases and the acquisition of chemoresistance. Metastatic NB is characterized by MYCN amplification that correlates with changes in the expression of miRNAs, which are small non-coding RNA sequences, playing a crucial role in NB development and chemoresistance. In the present study, miRNA expression was analyzed in two human MYCN-amplified NB cell lines, one sensitive (HTLA-230) and one resistant to Etoposide (ER-HTLA), by microarray and RT-qPCR techniques. These analyses showed that miRNA-15a, -16-1, -19b, -218, and -338 were down-regulated in ER-HTLA cells. In order to validate the presence of this down-regulation in vivo, the expression of these miRNAs was analyzed in primary tumors, metastases, and bone marrow of therapy responder and non-responder pediatric patients. Principal component analysis data showed that the expression of miRNA-19b, -218, and -338 influenced metastases, and that the expression levels of all miRNAs analyzed were higher in therapy responders in respect to non-responders. Collectively, these findings suggest that these miRNAs might be involved in the regulation of the drug response, and could be employed for therapeutic purposes.

Hypoxia downregulated miR-4521 suppresses gastric carcinoma progression through regulation of IGF2 and FOXM1

BACKGROUND

MicroRNAs (miRNAs) show considerable promise as therapeutic agents to improve tumor treatment, as they have been revealed as crucial modulators in tumor progression. However, our understanding of their roles in gastric carcinoma (GC) metastasis is limited. Here, we aimed to identify novel miRNAs involved in GC metastasis and explored their regulatory mechanisms and therapeutic significance in GC.

METHODS

The microRNA expression profiles of GC tumors at different stages and at different metastasis statuses were compared respectively using the stomach adenocarcinoma (STAD) miRNASeq dataset in TCGA. Using the above method, miR-4521 was picked out for further study. miR-4521 expression in GC tissues was examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). Highly and lowly invasive cell sublines were established using a repetitive transwell assay. Gain-of-function and loss-of-function analyses were performed to investigate the functions of miR-4521 and its upstream and downstream regulatory mechanisms in vitro and in vivo. Moreover, we investigated the therapeutic role of miR-4521 in a mouse xenograft model.

RESULTS

In this study, we found that miR-4521 expression was downregulated in GC tissues compared with adjacent normal tissues and that its downregulation was positively correlated with advanced clinical stage, metastasis status and poor patient prognosis. Functional experiments revealed that miR-4521 inhibited GC cell invasion and metastasis in vitro and in vivo. Further studies showed that hypoxia repressed miR-4521 expression via inducing ETS1 and miR-4521 mitigated hypoxia-mediated metastasis, while miR-4521 inactivated the AKT/GSK3β/Snai1 pathway by targeting IGF2 and FOXM1, thereby inhibiting the epithelial-mesenchymal transition (EMT) process and metastasis. In addition, we demonstrated that therapeutic delivery of synthetic miR-4521 suppressed gastric carcinoma progression in vivo.

CONCLUSIONS

Our results suggest an important role for miR-4521 in regulating GC metastasis and hypoxic response of tumor cells as well as the therapeutic significance of this miRNA in GC.

The Role of Non-Coding RNAs in Controlling Cell Cycle Related Proteins in Cancer Cells

Cell cycle is regulated by a number of proteins namely cyclin-dependent kinases (CDKs) and their associated cyclins which bind with and activate CDKs in a phase specific manner. Additionally, several transcription factors (TFs) such as E2F and p53 and numerous signaling pathways regulate cell cycle progression. Recent studies have accentuated the role of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in the regulation of cell cycle. Both lncRNAs and miRNAs interact with TFs participating in the regulation of cell cycle transition. Dysregulation of cell cycle regulatory miRNAs and lncRNAs results in human disorders particularly cancers. Understanding the role of lncRNAs, miRNAs, and TFs in the regulation of cell cycle would pave the way for design of anticancer therapies which intervene with the cell cycle progression. In the current review, we describe the role of lncRNAs and miRNAs in the regulation of cell cycle and their association with human malignancies.

Effects and mechanism of microRNA‑218 against lung cancer

Lung cancer is the most prevalent and observed type of cancer in Xuanwei County, Yunnan, South China. Lung cancer in this area is called Xuanwei lung cancer. However, its pathogenesis remains largely unknown. To date, a number of studies have shown that microRNA (miR)‑218 functions as a tumor suppressor in multiple types of cancer. However, the role of miR‑218 and its regulatory gene network in Xuanwei lung cancer have yet to be investigated. The current study identified that the expression levels of miR‑218 in XWLC‑05 cells were markedly lower compared with those in immortalized lung epithelial BEAS‑2B cells. The present study also demonstrated that overexpression of miR‑218 could decrease cell proliferation, invasion, viability and migration in Xuanwei lung cancer cell line XWLC‑05 and NSCLC cell line NCI‑H157. Additionally, the results revealed that overexpression of miR‑218 could induce XWLC‑05 and NCI‑H157 cell apoptosis by arresting the cell cycle at G2/M phase. Finally, the present study demonstrated that overexpression of miR‑218 could lead to a significant increase in phosphatase and tensin homolog (<em>PTEN</em>) and YY1 transcription factor (<em>YY1</em>), and a decrease in B‑cell lymphoma 2 (<em>BCL‑2</em>) and BMI1 proto‑oncogene, polycomb ring finger (<em>BMI‑1</em>) at the mRNA and protein level in XWLC‑05 and NCI‑H157 cell lines. However, we did not observe any remarkable difference in the roles of miR‑218 and miR‑218‑mediated regulation of <em>BCL‑2</em>, <em>BMI‑1</em>, <em>PTEN</em> and <em>YY1</em> expression in the progression of Xuanwei lung cancer. In conclusion, miR‑218 could simultaneously suppress cell proliferation and tumor invasiveness and induce cell apoptosis by increasing <em>PTEN</em> and <em>YY1</em> expression, while decreasing <em>BCL‑2</em> and <em>BMI‑1</em> in Xuanwei lung cancer. The results demonstrated that miR‑218 might serve a vital role in tumorigenesis and progression of Xuanwei lung cancer and overexpression of miR‑218 may be a novel approach for the treatment of Xuanwei lung cancer.

[Advancement of E2F1 in Common Tumors]

细胞周期相关转录因子E2F1（E2F transcription factor 1）是细胞周期相关转录因子E2F家族成员之一，主要参与包括细胞周期进展、DNA修复、DNA复制、细胞分化，增殖和凋亡等多种细胞过程。E2F1在全身多种肿瘤组织和细胞中呈高表达，起着促癌基因的作用，E2F1表达上调与肿瘤的发生、发展、转移及预后密切相关。因此，E2F1有望成为肿瘤治疗的新靶点。本文就E2F1在目前常见肿瘤中的最新研究进展做一综述。

lncRNA SNHG11 Promotes Gastric Cancer Progression by Activating the Wnt/β-Catenin Pathway and Oncogenic Autophagy

Long non-coding RNAs (lncRNAs) are under active investigation in the development of cancers, including gastric cancer (GC). Oncogenic autophagy is required for cancer cell survival. The present study aimed to investigate the regulatory role of lncRNA small nucleolar host gene 11 (SNHG11) in GC. We show that SNHG11 is upregulated in GC, and that its upregulation correlated with dismal patient outcomes. Functionally, SNHG11 aggravated oncogenic autophagy to facilitate cell proliferation, stemness, migration, invasion, and epithelial-to-mesenchymal transition (EMT) in GC. Mechanistically, SNHG11 post-transcriptionally upregulated catenin beta 1 (CTNNB1) and autophagy related 12 (ATG12) through miR-483-3p/miR-1276, while the processing of precursor (pre-)miR-483/pre-miR-1276 was hindered by SNHG11. SNHG11 induced GSK-3β ubiquitination through interacting with Cullin 4A (CUL4A) to further activate the Wnt/β-catenin pathway. Intriguingly, SNHG11 regulated autophagy in a manner dependent on ATG12 rather than the Wnt/β-catenin pathway, whereas SNHG11 contributed to the malignant behaviors of GC cells via both pathways. Finally, SNHG11 upregulation in GC cells was shown to be transcriptionally induced by TCF7L2. In conclusion, we reveal that SNHG11 is an onco-lncRNA in GC and might be a promising prognostic and therapeutic target for GC.

NFIB functions as an oncogene in estrogen receptor-positive breast cancer and is regulated by miR-205-5p

Nuclear factor I/B(NFIB) is a prominent transcription factor that plays a critical role in cancer progression. In this study, we found that the protein level of NFIB was significantly upregulated in estrogen receptor (ER) positive breast cancer tissues compared to matched adjacent noncancerous tissues while the NFIB mRNA expression level was not obviously dysregulated. Similarly, ER-positive breast cancer cell line, MCF7 express a high protein level of NFIB, while the mRNA level is not significantly upregulated. The function assays indicated that NFIB promoted MCF-7 cell cycle progression, cell proliferation and suppressed apoptosis in vitro. Furthermore, we explored the molecular mechanisms of NFIB as a target gene of miR-205-5p. Finally, we found that miR-205-5p was significantly downregulated in ER -positive breast cancer, and had the opposite eff ;ects on breast cancer cells compared with NFIB. Taken together, this study highlighted the molecular mechanisms of NFIB as an oncogene in ER-positive breast cancer, which was negatively regulated by miR-205-5p in breast cancer.

Glucose-induced microRNA-218 suppresses the proliferation and promotes the apoptosis of human retinal pigment epithelium cells by targeting RUNX2

OBJECTIVE

MicroRNA-218 (miR-218) critical for preventing the progression of numerous diseases, including diseases of the retinal pigment epithelium (RPE). However, the mechanism by which miR-218 regulates the PRE in humans remains largely unknown. Our study investigated the effects of glucose-induced miR-218 expression on human RPE cells (ARPE-19), as well as its targeted regulatory effect.

METHODS

The levels of miR-218 and runt-related transcription factor 2 (RUNX2) expression were investigated by RT-qPCR or Western blot assays. Cell viability and apoptosis were assessed by CCK-8 assays, flow cytometry, and Hoechst staining. A luciferase reporter assay was performed to determine whether Runx2 is a target gene of miR-218.

RESULTS

Our results showed that glucose up-regulated miR-218 expression, suppressed proliferation, and induced the apoptosis of ARPE-19 cells. We verified that miR-218 could inhibit the proliferation and facilitate the apoptosis of ARPE-19 cells, while inhibition of miR-218 expression produced the opposite effects. In terms of mechanism, we demonstrated that RUNX2 was a direct target of miR-218. Functional experiments showed that Runx2 served as a miR-218 target to help inhibit the proliferation and induction of apoptosis in ARPE-19 cells.

CONCLUSION

Our findings suggest the miR-218/Runx2 axis as a potential target for treating diabetic retinopathy (DR).

Steroid receptor RNA activator inhibits the migration, invasion and stemness characteristics of renal cell carcinoma cells

Renal cell carcinoma (RCC) has a high mortality rate among urological malignancies, and its underlying mechanisms remain unclear. Steroid receptor RNA coactivator (SRA) belongs to the long non-coding RNAs (lncRNAs) and has been demonstrated to be closely related to various types of cancer. In the present study, the decreased expression level of SRA was first confirmed in RCC tissues and cell lines by RT-qPCR. Using knockdown or overexpression systems, it was then found that SRA inhibited the proliferation of RCC cell lines and promoted their apoptosis. In addition, SRA suppressed the migration and invasion, and altered EMT-related markers in RCC cells. More importantly, it was demonstrated that SRA reduced percentage of CD44⁺/CD24⁻ cells and the sphere-forming efficiency. SRA also attenuated the expression levels of CD44, SOX-2, ABCG2 and OCT-4, which are all associated with cancer cell stemness characteristics. Although SRA increased the phosphorylation of extracellular-regulated protein kinase (ERK), the ERK1/2 pathway could not further interfere with the alteration of EMT-related markers mediated by SRA. Notably, the ERK inhibitor, PD98059, abolished ERK1/2 phosphorylation, whereas it did not exert any marked effects on cell proliferation and EMT-related markers mediated by SRA. Taken together, the findings of the present study indicate that SRA is an important molecule that inhibits the migration, invasion and stem cell characteristics of RCC cells; the ERK signaling pathway may not be involved in this process.

Guanine nucleotide-binding protein subunit beta-4 promotes gastric cancer progression via activating Erk1/2

Gastric cancer (GC) is one of the most common and lethal malignancies worldwide, and its poor prognosis is mainly due to the rapid tumor progression including tumor invasion, distant metastasis, etc. Understanding the molecular mechanisms regulating GC progression lays the basis for the development of targeted therapeutic agents. Increasing evidence suggests that guanine nucleotide-binding protein subunit beta-4 (GNB4), a key subunit of heterotrimeric G protein, plays a crucial role in the initiation and progression of multiple malignancies. However, whether and how GNB4 promotes GC progression are still unknown. In this study, we found that GNB4 was highly expressed in GC tissues compared to that in non-tumor tissues and was significantly associated with tumor invasion depth, pathological stage and poor survival rate of GC patients. Both gain-of-function and loss-of-function studies revealed that GNB4 significantly enhanced GC cell growth and motility both in vitro and in vivo. Further studies revealed that GNB4 overexpression induced G1-S transition and promoted the process of epithelial-mesenchymal transformation. These tumor promoting effects were mediated by GNB4 which activates the Erk1/2 pathway through upregulating Erk1/2 phosphorylation, as U0126, an Erk1/2 phosphorylation inhibitor, could significantly inhibit GNB4-mediated cell proliferation, migration and invasion. In summary, GNB4 contributes to the proliferation and metastasis of GC cells by activating the Erk1/2 signaling pathway, and it may serve as a potential therapeutic target of GC.

MiR-93 suppresses tumorigenesis and enhances chemosensitivity of breast cancer via dual targeting E2F1 and CCND1

Chemoresistance of tumors often leads to treatment failure in clinical practice, which underscores pivotal needs to uncover novel therapeutic strategies. Accumulating evidences show that microRNAs (miRNAs) are widely involved in carcinogenesis, but their function on chemoresistance remains largely unexplored. In this study, we found that miR-93-5p (miR-93) significantly inhibited cell proliferation, induced G1/S cell cycle arrest and increased chemosensitivity to paclitaxel (PTX) in vitro and in vivo. Moreover, two well-established oncogenes, E2F1 and CCND1, were identified as dual targets of miR-93. Knockdown of E2F1 and CCND1 reduced cell proliferation and PTX-sensitivity, whereas overexpression of them had the opposite effect. More importantly, overexpression of E2F1 and CCND1 antagonized miR-93-mediated cell cycle arrest and apoptosis. Further mechanistic study revealed that miR-93 exhibited its inhibitory role by directly targeting E2F1 and CCND1 to inactivate pRB/E2F1 pathway and AKT phosphorylation. Taken together, our findings suggested that miR-93 greatly improved chemosensitivity and potentially served as a novel therapeutic target for breast cancer treatment.

MiR-218-5p Suppresses the Progression of Retinoblastoma Through Targeting NACC1 and Inhibiting the AKT/mTOR Signaling Pathway

Introduction

MicroRNA-218-5p (miR-218-5p) was involved in the progression of multiple tumors as a tumor suppressor miRNA. Its specific role on human retinoblastoma (RB) cells remains unknown.

Methods

We constructed the miR-218-5p overexpression and knockdown cells to detect their role on RB cell line WERI-Rb-1, and we analyzed its binding sites on TargetScan. CCK8 and clonogenic assays were performed to detect cell viability. Flow cytometry was used for the detection of cell apoptosis.

Results

Our results showed that the miR-218-5p inhibitor enhanced cell viability and blocked the apoptosis in RB cells. The AKT/mTOR signaling pathway was also inhibited by the miR-218-5p inhibitor. MiR-218-5p mimics lead to diametrically opposite results. Nucleus accumbens-associated 1 (NAC1) encoded by the NACC1 gene is involved in the regulation of many biological functions, including gene transcription, protein degradation of ubiquitin pathway, cell viability, and apoptosis. In this research, dataset analysis suggested that NACC1 might be a downstream target of miR-218-5p. Then, qPCR and Western blot analysis proved that miR-218-5p inhibited the expression of NACC1 in RB cells. NACC1 could promote cell viability and inhibit the apoptosis by activating the AKT/mTOR signaling pathway. MiR-218-5p mimics blocked the enhancement of cell growth induced by NACC1 overexpression as well as the activation of the AKT/mTOR signaling pathway in RB cells.

Discussion

MiR-218-5p inhibited cell growth by targeting NACC1 and suppressing the AKT/mTOR signaling pathway. MiR-218-5p/NACC1/AKT/mTOR might be a new target axis for the clinical treatment strategy.

microRNA-524-5p inhibits proliferation and induces cell cycle arrest of osteosarcoma cells via targeting CDK6

BACKGROUND

Osteosarcoma (OS) is one of the most commonly diagnosed malignant tumors that mainly affects children and adolescents. The underlying molecular mechanisms that are responsible for the initiation and development of OS are still not clear. Increasing evidence suggested the tumor suppressor role of microRNA-524-5p in a variety of cancers via targeting key pathways involved in tumorigenesis. The aim of this study was to characterize the function of miR-524-5p in OS.

METHODS

A total 50 paired OS tissues and adjacent normal tissues were collected from OS patients. The expression of miR-524-5p in OS tissues and cells was detected by RT-qPCR. The CCK-8 assay, flow cytometry and transwell assay were applied to determine the proliferation and invasion abilities of OS cells. The targets of miR-524-5p were predicted using the miRDB dataset and confirmed by luciferase reporter assay and western blot analysis.

RESULTS

The expression of miR-524-5p was decreased in OS tissues and cell lines. OS patients with lymph node metastasis harbored relative lower level of miR-524-5p. Overexpression of miR-524-5p in OS cells significantly suppressed the proliferation, drove cell cycle arrest and apoptosis. The mechanism investigation revealed that miR-524-5p bound the 3'-untranslated region (UTR) of Cyclin Dependent Kinase 6 (CDK6) and repressed the expression of CDK6 in OS cells. Overexpressed CDK6 was found in OS tissues, which was inversely correlated with that of miR-524-5p. Moreover, forced expression of CDK6 significantly reversed the anti-cancer effects of miR-524-5p on the proliferation, apoptosis and cell cycle arrest of OS cells.

CONCLUSIONS

Our results identified the tumor-suppressive role of miR-524-5p in OS via targeting CDK6, which may lead to the identification of novel therapeutic target for the treatment of OS.

Non-coding RNAs in gastric cancer

Non-coding RNAs (ncRNAs) are functional RNA molecules that play crucial regulatory roles in many fundamental biological processes. The dysregulation of ncRNAs is significantly associated with the progression of human cancers, including gastric cancer. In this review, we have summarized the oncogenic or tumor-suppressive roles and the regulatory mechanisms of lncRNAs, miRNAs, circRNAs and piRNAs, and have discussed their potential as biomarkers or therapeutic targets in gastric cancer.

Tumor-suppressive miR-3650 inhibits tumor metastasis by directly targeting NFASC in hepatocellular carcinoma

In recent years, a growing body of evidence has provided support for the important role of microRNAs (miRNAs) in the progression of human cancers. A recent study showed that a novel miRNA miR-3650 expression was significantly decreased in hepatocellular carcinoma (HCC). However, the precise role of miR-3650 in HCC have remained poorly understood. In this study, we found that miR-3650 expression was frequently decreased in HCC tissues. Low expression of miR-3650 is positively associated with tumor metastasis and poor survival of HCC patients. Forced expression of miR-3650 significantly inhibited the migration and epithelial-mesenchymal transition (EMT) of HCC cells. Through bioinformatic analysis and luciferase assays, we confirmed that neurofascin (NFASC) is a directly target mRNA of miR-3650. Rescue experiment demonstrated that NAFSC overexpression could partially counteracted the inhibitory effect of miR-3650 in HCC metastasis and EMT. In conclusion, our findings are the first time to demonstrate that reduced expression of miR-3650 in HCC was correlated with tumor metastasis and poor survival. MiR-3650 repressed HCC migration and EMT by directly targeting NFASC. Our findings suggested that miR-3650 may serve as a potential prognostic marker and promising application in HCC therapy.

Histone Deacetylase Inhibitor Sensitizes ERCC1-High Non-small-Cell Lung Cancer Cells to Cisplatin via Regulating miR-149

Resistance to platinum-based chemotherapy becomes a major obstacle in non-small-cell lung cancer (NSCLC) treatment. Overexpression of the excision repair cross-complementing 1 (ERCC1) gene is reported to negatively influence the effectiveness of cisplatin-based therapy for NSCLC cells. In this study, we confirm that high ERCC1 expression correlates with cisplatin resistance in NSCLC cells. Importantly, histone deacetylase inhibitors (HDACis) re-sensitize ERCC1-high NSCLC cells to cisplatin both in vitro and in vivo. Mechanistically, the HDACi induces the expression of miR-149 by acetylation and activation of E2F1, which directly targets ERCC1 and inhibits ERCC1 expression. Inhibition of miR-149 reverses the promotion effect of HDACis on cisplatin-induced DNA damage and cell apoptosis in ERCC1-high NSCLC cells. In conclusion, this study reveals a novel mechanism by which HDACis re-sensitizes ERCC1-high NSCLC cells to cisplatin via regulation of the E2F1/miR-149/ERCC1 axis, and we propose that combination of HDACis and cisplatin might hold promise to be a more effective therapeutic paradigm for ERCC1-high NSCLCs.

A preliminary study of microRNA expression in different types of primary melanoma

MicroRNAs (miRNAs) have been proven to regulate the development and progression of cancer through various mechanisms. The aim of the present study was to compare miRNA expression between primary melanomas from different sites. We analyzed the expression of 84 miRNAs in 27 primary melanoma and 5 nevus formalin-fixed paraffin-embedded (FFPE) samples using the Human Cancer PathwayFinder miScript miRNA PCR Array. The FFPE samples were obtained from the archives of the Municipal Clinical Emergency Hospital of Timisoara and included 10 cutaneous melanomas, 10 uveal melanomas, 7 mucosal melanomas, and 5 cutaneous nevi. Out of 84 miRNAs, 11 miRNAs showed altered expression in all types of melanoma compared with the nevi. Among these, miR-155-5p, miR-9-5p, miR-142-5p, miR-19a-3p, miR-134-5p, and miR-301a-3p were upregulated, while miR-205-5p, miR-203a-3p, miR-27b-3p, miR-218-5p, and miR-23b-3p were downregulated. The highest similarity in miRNA expression pattern was found between uveal and mucosal melanoma groups, i.e., 15 miRNAs had altered expression in both groups. Overall, we identified several miRNAs with significantly altered expression in primary melanomas, including those reported for the first time in this type of cancer. Among them, mir-9-5p, mir-203a-3p, mir-19a-3p, mir-27b-3p, and mir-218-5p showed altered expression in all three melanoma types vs. nevi. Further research should explore the potential of these miRNAs in melanoma.