LncRNA AFAP1-AS1 Promotes Oral Squamous Cell Carcinoma Development by Ubiquitin-Mediated Proteolysis.

BACKGROUND AND PURPOSE: Long noncoding RNA (lncRNA) dysregulation has been reported to play a pivotal role in the development of cancers. In this study, we aimed to screen the key lncRNA in oral squamous cell carcinoma (OSCC) via bioinformatics analysis and further validate the function of lncRNA in vitro and in vivo. METHODS: Bioinformatics analysis was conducted to identify differentially expressed lncRNAs between control and OSCC samples. Quantitative real-time-polymerase chain reaction was employed to detect the expression of differentially expressed lncRNAs in human tongue squamous cell carcinoma and human oral keratinocytes cell lines. The biological function of lncRNA and its mechanism were examined via the experimental assessment of the cell lines with the lncRNA overexpressed and silenced. Additionally, to further explore the function of lncRNA in the progression of OSCC, xenograft tumour mouse models were established using 25 mice (5 groups, each with 5 mice). Tumour formation was observed at 2 weeks after the cell injection, and the tumours were resected at 5 weeks post-implantation. RESULTS: Two lncRNAs, LINC00958 and AFAP1-AS1, were found to be correlated with the prognosis of OSCC. The results of the quantitative real-time-polymerase chain reaction indicated that the 2 lncRNAs were highly expressed in OSCC. In combination with the previous literature, we found AFAP1-AS1 to be a potentially important biomarker for OSCC. Thus, we further investigated its biological function and found that AFAP1-AS1 silencing inhibited cell proliferation, migration, and invasion whereas AFAP1-AS1 overexpression reversed the effect of AFAP1-AS1 silencing (P < .05). Mechanism analysis revealed that AFAP1-AS1 regulated the development of OSCC through the ubiquitin-mediated proteolysis pathway. CONCLUSIONS: AFAP1-AS1 is an oncogene that aggravates the development of OSCC via the ubiquitin-mediated proteolysis pathway. It also provides a novel potential therapy for OSCC.

Proliferation, apoptosis and invasion of human lung cancer cells are associated with NFATc1.

The expression of nuclear factor of activated T cells c1 (NFATc1) is closely associated with the progression of numerous types of cancer. When NFATc1 expression becomes dysregulated in some types of cancer, this alteration can promote malignant transformation and thereby progression of cancer. NFATc1 expression has been demonstrated to be upregulated in lung cancer cells. This suggests that knockdown of NFATc1 in lung cancer cells may be a therapeutic marker for the treatment of cancer. In the present study, the effects of NFATc1 on the proliferation, apoptosis, invasion and migration of NCI-H1299 and A549 lung cancer cell lines were explored. Lentivirus infection was used to establish a cell model of NFATc1 knockdown in A549 and NCI-H1299 lung cancer cells. Reverse transcription-quantitative PCR was subsequently performed to detect NFATc1 expression in these human lung cancer cells. MTT, wound healing, colony formation and Transwell invasion assays, and flow cytometry were then performed to measure the proliferation, invasion, apoptosis and cell cycle of the cells. Finally, western blot analysis was performed to investigate the mechanism underlying the involvement of NFATc1 in these processes. NFATc1 knockdown was found to significantly inhibit the proliferation, clone formation, migration and invasion of the cells. Furthermore, the cell cycle was arrested at the G1 phase and the expression levels of the target proteins located downstream in the signaling pathway, namely CDK4, c-Myc, ERK, p38 and N-cadherin, were decreased. Following NFATc1 knockdown, the percentages of apoptotic cells were increased, and the expression levels of Bax, cleaved caspase-3 and E-cadherin were also increased. Taken together, the results of the present study suggested that NFATc1 serves an oncogenic role in lung cancer. In terms of the underlying mechanism, NFATc1 promoted the proliferation of lung cancer cells by inhibiting the MAPK and epithelial-to-mesenchymal transition signaling pathways, suggesting that NFATc1 may be a novel target for therapeutic intervention for the treatment of lung cancer.

Knockdown of LINC00511 decreased cisplatin resistance in non-small cell lung cancer by elevating miR-625 level to suppress the expression of leucine rich repeat containing eight volume-regulated anion channel subunit E.

BACKGROUND: LINC00511 has been reported as a biomarker related to the prognosis of non-small cell lung cancer (NSCLC), but the molecular mechanism and exact functions of LINC00511 in chemoresistance of NSCLC remain to be elucidated. METHODS: RT-qPCR was used to evaluate the mRNA expression of LINC00511, miR-625, and leucine rich repeat containing 8 volume-regulated anion channel subunit E (LRRC8E). Western blotting detected the protein levels of Ki-67, MMP-9, cleaved-caspase-3. The interaction between miR-625 and LINC00511 or LRRC8E was verified by luciferase reporter assays. CCK-8, TUNEL, and Transwell assays were used to evaluate IC50 value, proliferation, migration, and invasion of NSCLC cells. RESULTS: In our study, it was discovered that the levels of LINC00511 and LRRC8E were increased, while miR-625 expression was decreased in NSCLC tissues, DDP-resistant NSCLC cells, and non-resistant NSCLC cells. LINC00511 depletion significantly curbed cell growth, IC50 value, and metastasis in DDP-resistant NSCLC cells. In addition, the influence of LINC00511 deficiency on the DDP resistance in NSCLC was overturned by suppressing miR-625. Furthermore, LRRC8E overexpression abolished the promotive effect of miR-625 abundance on the DDP sensitivity in DDP-resistant NSCLC cells. CONCLUSION: Our results demonstrated that LINC00511 increased DDP resistance in NSCLC by suppressing miR-625 to upregulate LRRC8E.

Iodine-125 seed represses the growth and facilitates the apoptosis of colorectal cancer cells by suppressing the methylation of miR-615 promoter.

BACKGROUND: Colorectal cancer (CRC) represents a common malignancy in gastrointestinal tract. Iodine-125 (125I) seed implantation is an emerging treatment technology for unresectable tumors. This study investigated the mechanism of 125I seed in the function of CRC cells. METHODS: The CRC cells were irradiated with different doses of 125I seed (0.4, 0.6 and 0.8 mCi). miR-615 expression in CRC tissues and adjacent tissues was detected by RT-qPCR. miR-615 expression was intervened with miR-615 mimic or miR-615 inhibitor, and then the CRC cells were treated with 5-AZA (methylation inhibitor). The CRC cell growth, invasion and apoptosis were measured. The methylation level of miR-615 promoter region was detected. The xenograft tumor model irradiated by 125I seed was established in nude mice. The methylation of miR-615, Ki67 expression and CRC cell apoptosis were detected. RESULTS: 125I seed irradiation repressed the growth and facilitated apoptosis of CRC cells in a dose-dependent manner. Compared with adjacent tissues, miR-615 expression in CRC tissues was downregulated and miR-615 was poorly expressed in CRC cells. Overexpression of miR-615 suppressed the growth of CRC cells. 125I seed-irradiated CRC cells showed increased miR-615 expression, reduced growth rate and enhanced apoptosis. The methylation level of miR-615 promoter region in CRC cells was decreased after 125I seed treatment. In vivo experiments confirmed that 125I seed-irradiated xenograft tumors showed reduced methylation of the miR-615 promoter and increased miR-615 expression, as well as decreased Ki67 expression and enhanced apoptosis. The target genes of miR-615 and its regulatory downstream pathway were further predicted by bioinformatics analysis. CONCLUSIONS: 125I seed repressed the growth and facilitated the apoptosis of CRC cells by suppressing the methylation of the miR-615 promoter and thus activating miR-615 expression. The possible mechanism was that miR-615-5p targeted MAPK13, thus affecting the MAPK pathway and the progression of CRC.

Identification and Validation of a Four-Long Non-coding RNA Signature Associated With Immune Infiltration and Prognosis in Colon Cancer.

The emerging evidence has demonstrated the critical roles of long non-coding RNAs (lncRNAs) as regulators in the tumor immune microenvironment (TIME). However, the tumor immune infiltration-associated lncRNAs and their clinical significance in colon cancer have not yet been thoroughly investigated. This study performed an integrative analysis of lncRNA expression profiles and immune cell infiltration profiles and identified 258 immune infiltration-associated lncRNAs. Of them, four lncRNAs (AC008494.3, LINC00926, AC022034.1, and SNHG26) were significantly and independently associated with the patient's overall survival. Finally, we developed a tumor immune infiltration-associated lncRNA signature (TIILncSig) comprising of these four lncRNAs, which can divide colon cancer patients of The Cancer Genome Atlas (TCGA) into high-risk and low-risk groups with a significantly different outcome [Hazard ratio (HR) = 2.718, 95% CI = 1.955-3.779, p < 0.001]. Prognostic performance of the TIILncSig was further validated in another independent colon cancer cohort (HR = 1.832, 95% CI = 1.045-3.21, p = 0.034). Results of multivariate Cox regression and stratification analysis demonstrated that the TIILncSig is an independent predictive factor from other clinical features (HR = 2.687, 95% CI = 1.912-3.776, p < 0.001 for TCGA cohort and HR = 1.837, 95% CI = 1.047-3.223, p = 0.034 for GSE17538 cohort). Literature analysis provided experimental evidence supporting roles of the TIILncSig in cancer carcinogenesis and progression and immune regulation. Summary, our study will help to understand the mechanisms of lncRNAs in immune regulation in the tumor microenvironment and provide novel biomarkers or targets for prognosis prediction and therapy decision-making for patients with colon cancer.

CircKEAP1 Suppresses the Progression of Lung Adenocarcinoma via the miR-141-3p/KEAP1/NRF2 Axis.

BACKGROUND: Lung cancer is the leading cause of death from cancer, and lung adenocarcinoma (LUAD) is the most common form. Despite the great advances that has been made in the diagnosis and treatment for LUAD, the pathogenesis of LUAD remains unclear. In this study, we aimed to identify the function of circKEAP1 derived from the exon of KEAP1 in LUAD. METHODS: The expression profiles of circRNAs in LUAD tissues and adjacent non-tumor tissues were analyzed by Agilent Arraystar Human CircRNA microarray. The levels and prognostic values of circKEAP1 in tissues and cancer cell lines were determined by quantitative real-time PCR (qRT-PCR). Subsequently, the effects of circKEAP1 on tumor growth were investigated by functional experiments in vitro and in vivo. Mechanistically, the dual luciferase reporter assay, RNA pull-down, and RNA immunoprecipitation experiments were performed to confirm the interaction between circKEAP1 and miR-141-3p in LUAD. RESULTS: We found circKEAP1 was significantly downregulated in LUAD tissues and repressed tumor growth both in vitro and in vivo. Mechanistically, circKEAP1 competitively binds to miR-141-3p and relive miR-141-3p repression for its host gene, which activated the KEAP1/NRF2 signal pathway, and finally suppresses the tumor progress. Our findings suggest that circKEAP1 inhibits LUAD progression through circKEAP1/miR-141-3p/KEAP1 axis and it may serve as a novel method for the treatment of LUAD.

circRNA-002178 act as a ceRNA to promote PDL1/PD1 expression in lung adenocarcinoma.

Circular RNAs (circRNAs) have been identified play a vital role in various different types of cancer via sponging miRNAs (microRNAs). However, their role in lung adenocarcinoma (LUAD) remains largely unclear. In this study, we systematically characterized the circRNA expression profiles in the LUAD cancer tissues and paired adjacent non-cancerous tissues. Three circRNAs were found to be significantly upregulated. Among them, has-circRNA-002178 was further confirmed to be upregulated in the LUAD tissues, and LUAD cancer cells. Subsequently, we also found has-circRNA-002178 could enhance PDL1 expression via sponging miR-34 in cancer cells to induce T-cell exhaustion. More importantly, circRNA-002178 could be detected in exosomes of plasma from LUAD patients and could serve as biomarkers for LUAD early diagnosis. Finally, we found circRNA-002178 could be delivered into CD8+ T cells to induce PD1 expression via exosomes. Taken together, our study revealed that circRNA-002178 could act as a ceRNA to promote PDL1/PD1 expression in lung adenocarcinoma.

CUTL1 induces epithelial-mesenchymal transition in non-small cell lung cancer.

The homeobox transcription factor CUTL1 has been associated with cellular proliferation and cell cycle progression, and CUTL1 functions as an oncogene. The aim of the present study was to investigate whether CUTL1 participates in epithelial-mesenchymal transition (EMT). The expression levels of CUTL1, E-cadherin, N-cadherin and Snail were determined by immunohistochemistry assay, immunofluorescence assay or real-time quantitative reverse transcription PCR. Their roles in non-small cell lung cancer (NSCLC) were assessed by functional analyses. Protein expression was detected by western blot analysis. The CUTL1 expression levels are higher in non-small cell lung cancer (NSCLC) tissues. High CUTL1 expression in NSCLC is associated with the mesenchymal-like phenotype. Mechanistically, CUTL1 upregulates transforming growth factor ß receptor I (TßR-I) expression, and the TßR-I inhibitor SB431542 abolishes EMT elicited by ectopic CUTL1 expression. Transforming growth factor ß (TGF-ß) signaling is essential for CUTL1-induced EMT in NSCLC cells. CUTL1 is downstream of TGF-ß signaling and CUTL1 is involved in the expression of the TßR-I. This study indicates that CUTL1 may be a potential target for anti-lung cancer therapy.

miR-455-5p promotes cell growth and invasion by targeting SOCO3 in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. miR-455-5p has increased expression and the ability to promote tumorigenesis in certain cancers. However, the role of miR-455-5p in NSCLC has not been sufficiently investigated. SOCS3 (suppressor of cytokine signaling 3), an important tumor suppressor, is often aberrantly inactivated in various tumors, but it is currently unclear whether SOCO3 is a target of miR-455-5p. In the present study, we investigated the role of miR-455-5p in NSCLC. We found that the expression of miR-455-5p was up-regulated in NSCLC tumor tissues compared to corresponding noncancerous tissues, and its expression was correlated with metastasis and tumor node metastasis in NSCLC tissue. We then showed that miR-455-5p promoted migration, invasion and proliferation in NSCLC cell lines. Additionally, we also found that SOCS3 was the direct target gene of miR-455-5p. Consistently, the expression of SOCS3 was negatively correlated with the expression of miR-455-5p in NSCLC tissues. We further show that aberrant miR-455-5p expression is partially controlled by activated ERK signaling in NSCLC. Therefore, miR-455-5p could enhance the growth and metastasis of NSCLC by inhibiting SOCS3, thus providing a potential molecular therapeutic target for the treatment of NSCLC patients.

FOSL2 positively regulates TGF-ß1 signalling in non-small cell lung cancer.

Fos-related antigen 2 (FRA-2/FOSL2) belongs to the AP-1 transcription factor family. Although FOSL2 has been shown to be involved in diverse physiological and pathological processes, very little is known about the signalling pathways that regulate FOSL2 expression and the mechanisms of FOSL2 function. Here, we show that FOSL2 expression is regulated by TGF-ß1 and that FOSL2 is required for TGF-ß1-induced migration. We demonstrate that FOSL2 interacts with Smad3 in vitro and in vivo and thus up-regulates TGF-ß1-induced signalling responses. Mechanistically, FOSL2 promotes P300 binding to Smad3 and the acetylation of Smad3 by P300. Furthermore, we show that the expression of FOSL2 correlates with activated Smad3 expression in clinical non-small cell lung cancer (NSCLC) samples. In summary, the present study indicates that FOSL2 facilitates TGF-ß1-induced migration by interaction with Smad3 in NSCLC and suggests FOSL2 as a potential therapeutic target for NSCLC.