The Pseudogene DUXAP8 Promotes Non-small-cell Lung Cancer Cell Proliferation and Invasion by Epigenetically Silencing EGR1 and RHOB.

Recently, the non-protein-coding functional elements in the human genome have been identified as key regulators in postgenomic biology, and a large number of pseudogenes as well as long non-coding RNAs (lncRNAs) have been found to be transcribed in multiple human cancers. However, only a small proportion of these pseudogenes has been functionally characterized. In this study, we screened for pseudogenes associated with human non-small-cell lung cancer (NSCLC) by comparative analysis of several independent datasets from the GEO. We identified a transcribed pseudogene named DUXAP8 that is upregulated in tumor tissues. Patients with higher DUXAP8 expression exhibited shorter survival, suggesting DUXAP8 as a new candidate prognostic marker for NSCLC patients. Knockdown of DUXAP8 impairs cell growth, migration, and invasion, and induces apoptosis both in vitro and in vivo. Mechanistically, DUXAP8 represses the tumor suppressors EGR1 and RHOB by recruiting histone demethylase LSD1 and histone methyltransferase EZH2, thereby promoting cell proliferation, migration, and invasion. These findings indicate that the pseudogene DUXAP8 may act as an oncogene in NSCLC by silencing EGR1 and RHOB transcription by binding with EZH2 and LSD1, which may offer a novel therapeutic target for this disease.

Long intergenic non-coding RNA 00152 promotes lung adenocarcinoma proliferation via interacting with EZH2 and repressing IL24 expression.

BACKGROUND: Numerous studies have shown that long non-coding RNAs (lncRNAs) behave as a novel class of transcript during multiple cancer processes, such as cell proliferation, apoptosis, migration, and invasion. LINC00152 is located on chromosome 2p11.2, and has a transcript length of 828 nucleotides. The biological role of LINC00152 in LAD(lung adenocarcinoma) remains unknown. METHODS: Quantitative reverse transcription PCR(qRT-PCR) was used to detect LINC00152 expression in 60 human LAD tissues and paired normal tissues. In vitro and in vivo studies showed the biological function of LINC00152 in tumour progression. RNA transcriptome sequencing technology was performed to identify the downstream suppressor IL24(interleukin 24) which was further examined by qRT-PCR, western bolt and rescue experiments. RNA immunoprecipitation (RIP), RNA pulldown, and Chromatin immunoprecipitation (ChIP) assays were carried out to reveal the interaction between LINC00152, EZH2 and IL24. RESULTS: LINC00152 expression was upregulated in 60 human LAD tissues and paired normal tissues. High levels of LINC00152 expression were correlated with advanced TNM stage, larger tumor size, and lymph node metastasis, as well as shorter survival time. Silencing of LINC00152 suppressed cell growth and induced cell apoptosis. LINC00152 knockdown altered the expression of many downstream genes, including IL24. LINC00152 could interact with EZH2 and inhibit IL24 transcription. Moreover, the ectopic expression of IL24 repressed cell proliferation and partly reversed LINC00152 overexpression-induced promotion of cell growth in LAD. CONCLUSIONS: Our study reveals an oncogenic role for LINC00152 in LAD tumorigenesis, suggesting that it could be used as a therapeutic target in LAD treatment.

Decreased long noncoding RNA MIR31HG is correlated with poor prognosis and contributes to cell proliferation in gastric cancer.

Long noncoding RNAs (lncRNAs) are emerging as key regulators governing fundamental biological processes, and their disorder expression involves in the development of several human cancers. MIR31HG, an lncRNA located in 9p21.3 and 2166 bp in length, has been found to be upregulated in breast cancer and contributes to cell proliferation and invasion. However, the expression pattern and biological function of MIR31HG in gastric cancer are still not well documented. In this study, we found that MIR31HG expression is decreased in gastric cancer tissues and associated with larger tumor size and advanced pathological stage. Patients with lower MIR31HG expression had a relatively poor prognosis. Furthermore, ectopic over-expression of MIR31HG could inhibit gastric cancer (GC) cell proliferation both in vitro and in vivo, while knockdown of MIR31HG by small interfering RNA (siRNA) promoted cell proliferation in GC cells partly via regulating E2F1 and p21 expression. Our findings present that decreased MIR31HG is involved in GC development and could be identified as a poor prognostic biomarker in GC patients.

Decreased long noncoding RNA SPRY4-IT1 contributing to gastric cancer cell metastasis partly via affecting epithelial-mesenchymal transition.

BACKGROUND: Long noncoding RNAs (lncRNAs) are emerging as key regulators governing fundamental biological processes, and their disorder expression involves in tumorigenesis. SPRY4-IT1 (SPRY4 intronic transcript 1), a lncRNA derived from an intron within SPRY4 gene, involves in multiple cancers development. However, the expression pattern and biological function of SPRY4-IT1 in gastric cancer is still not well documented. Hence, we carried out the present study to investigate the potential role of SPRY4-IT1 in gastric carcinogenesis. METHODS: QRT-PCR was performed to detect the expression of SPRY4-IT1 in 61 pairs of gastric cancer samples. Over-expression and RNA interference (RNAi) approaches were used to investigate the biological functions of SPRY4-IT1. The effect of SPRY4-IT1 on proliferation was evaluated by MTT and colony formation assays. Gastric cancer cells transfected with pCDNA-SPRY4-IT1 were injected into nude mice to study the effect of SPRY4-IT1 on tumorigenesis and metastasis in vivo. Protein levels of SPRY4-IT1 targets were determined by western blot or fluorescence immunohistochemistry. ChIP assays were performed to investigate the effect of DNMT1 on SPRY4-IT1 expression. Differences between groups were tested for significance using Student's t test (two-tailed). RESULTS: SPRY4-IT1 expression is decreased in gastric cancer tissues and associated with larger tumor size, advanced pathological stage, deeper depth of invasion and lymphatic metastasis. Patients with lower SPRY4-IT1 expression had a relatively poor prognosis. DNA methylation may be a key factor in controlling the SPRY4-IT1 expression. Furthermore, SPRY4-IT1 contributed to gastric cancer cells metastasis might partly via regulating epithelial-mesenchymal transition (EMT) process. CONCLUSION: Low expression of SPRY4-IT1 is involved in progression and metastasis of gastric cancer and may represent a novel biomarker of poor prognosis in patients with gastric cancer.

HOXA5 indicates poor prognosis and suppresses cell proliferation by regulating p21 expression in non small cell lung cancer.

Homeobox genes, a superfamily of evolutionarily conserved developmental genes, function as critical master regulatory factors in controlling body plan specification and cell fate determination. Recently, a substantial body of evidence indicates that the aberrant Homeobox (HOX) genes also play key roles in the development of cancers. Many reports have shown not only that HOX gene expression is upregulated or downregulated in many cancers but also that the expression of specific HOX genes tends to differ based on tissue type. Homeobox A5 (HOXA5) is a master regulator of the morphogenesis and cell differentiation, and its expression is also downregulated in many cancers mediated by DNA methylation. However, its biological role and clinical significance in nonsmall cell lung cancer (NSCLC) development and progression are not well documented. In this study, we found that expression levels of HOXA5 were significantly decreased in NSCLC tissues compared with adjacent normal tissues. Its expression level was significantly correlated with tumor-node-metastasis (TNM) stages, tumor size, and lymph node metastasis. Moreover, patients with lower levels of HOXA5 expression had a relatively poor prognosis. Furthermore, ectopic overexpression of HOXA5 could inhibit cell proliferation and invasion, while knockdown HOXA5 by siRNA promoted cell proliferation in NSCLC cells partly via regulating p21 expression. Our findings present that decreased HOXA5 could be identified as a poor prognostic biomarker in NSCLC and regulate cell proliferation and invasion.

Lnc RNA HOTAIR functions as a competing endogenous RNA to regulate HER2 expression by sponging miR-331-3p in gastric cancer.

BACKGROUND: Accumulating evidence indicates that the long non-coding RNA HOTAIR plays a critical role in cancer progression and metastasis. However, the overall biological role and clinical significance of HOTAIR in gastric carcinogenesis remains largely unknown. METHODS: HOTAIR expression was measured in 78 paired cancerous and noncancerous tissue samples by real-time PCR. The effects of HOTAIR on gastric cancer cells were studied by overexpression and RNA interference approaches in vitro and in vivo. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation (RIP). The positive HOTAIR/HER2 interaction was identified and verified by immunohistochemistry assay and bivariate correlation analysis. RESULTS: HOTAIR upregulation was associated with larger tumor size, advanced pathological stage and extensive metastasis, and also correlated with shorter overall survival of gastric cancer patients. Furthermore, HOTAIR overexpression promoted the proliferation, migration and invasion of gastric carcinoma cells, while HOTAIR depletion inhibited both cell invasion and cell viability, and induced growth arrest in vitro and in vivo. In particular, HOTAIR may act as a ceRNA, effectively becoming a sink for miR-331-3p, thereby modulating the derepression of HER2 and imposing an additional level of post-transcriptional regulation. Finally, the positive HOTAIR/HER2 correlation was significantly associated with advanced gastric cancers. CONCLUSIONS: HOTAIR overexpression represents a biomarker of poor prognosis in gastric cancer, and may confer malignant phenotype to tumor cells. The ceRNA regulatory network involving HOTAIR and the positive interaction between HOTAIR and HER2 may contribute to a better understanding of gastric cancer pathogenesis and facilitate the development of lncRNA-directed diagnostics and therapeutics against this disease.

Downregulation of BRAF activated non-coding RNA is associated with poor prognosis for non-small cell lung cancer and promotes metastasis by affecting epithelial-mesenchymal transition.

BACKGROUND: Recent evidence indicates that long noncoding RNAs (lncRNAs) play a critical role in the regulation of cellular processes, such as differentiation, proliferation and metastasis. These lncRNAs are found to be dysregulated in a variety of cancers. BRAF activated non-coding RNA (BANCR) is a 693-bp transcript on chromosome 9 with a potential functional role in melanoma cell migration. The clinical significance of BANCR, and its' molecular mechanisms controlling cancer cell migration and metastasis are unclear. METHODS: Expression of BANCR was analyzed in 113 non-small cell lung cancer (NSCLC) tissues and seven NSCLC cell lines using quantitative polymerase chain reaction (qPCR) assays. Gain and loss of function approaches were used to investigate the biological role of BANCR in NSCLC cells. The effects of BANCR on cell viability were evaluated by MTT and colony formation assays. Apoptosis was evaluated by Hoechst staining and flow cytometry. Nude mice were used to examine the effects of BANCR on tumor cell metastasis in vivo. Protein levels of BANCR targets were determined by western blotting and fluorescent immunohistochemistry. RESULTS: BANCR expression was significantly decreased in 113 NSCLC tumor tissues compared with normal tissues. Additionally, reduced BANCR expression was associated with larger tumor size, advanced pathological stage, metastasis distance, and shorter overall survival of NSCLC patients. Reduced BANCR expression was found to be an independent prognostic factor for NSCLC. Histone deacetylation was involved in the downregulation of BANCR in NSCLC cells. Ectopic expression of BANCR impaired cell viability and invasion, leading to the inhibition of metastasis in vitro and in vivo. However, knockdown of BANCR expression promoted cell migration and invasion in vitro. Overexpression of BANCR was found to play a key role in epithelial-mesenchymal transition (EMT) through the regulation of E-cadherin, N-cadherin and Vimentin expression. CONCLUSION: We determined that BANCR actively functions as a regulator of EMT during NSCLC metastasis, suggesting that BANCR could be a biomarker for poor prognosis of NSCLC.

Long non-coding RNA MVIH indicates a poor prognosis for non-small cell lung cancer and promotes cell proliferation and invasion.

Long non-coding RNAs (lncRNAs) have emerged as major players in governing fundamental biological processes, and many of which are misregulated in multiple cancers and likely to play a functional role in tumorigenesis. Therefore, identification of cancer-associated lncRNAs and investigation of their biological functions and molecular mechanisms are important for understanding the development and progression of cancer. lncRNA associated with microvascular invasion in HCC (lncRNA MVIH) was found to be generally upregulated in HCC. Moreover, MVIH overexpression could serve as an independent risk factor to predict poor RFS and promote tumor growth and metastasis via activating angiogenesis. However, its biological role and clinical significance in non-small cell lung cancer (NSCLC) development and progression is unknown. In this study, we found that lncRNA MVIH levels were increased in NSCLC tissues compared with adjacent normal tissues. Its expression level was significantly correlated with TNM stages, tumor size, and lymph node metastasis. Moreover, patients with high levels of MVIH expression had a relatively poor prognosis. Furthermore, knockdown of MVIH expression by siRNA could inhibit cell proliferation and invasion, while ectopic expression of MVIH promoted cell proliferation and invasion in NSCLC cells partly via regulating MMP2 and MMP9 protein expression. Our findings present that increased lncRNA MVIH could be identified as a poor prognostic biomarker in NSCLC and regulate cell proliferation and invasion.

Effects of methionine deficiency on B7H3-DAP12-CAR-T cells in the treatment of lung squamous cell carcinoma.

Lung squamous cell carcinoma (LUSC) is a subtype of lung cancer for which precision therapy is lacking. Chimeric antigen receptor T-cells (CAR-T) have the potential to eliminate cancer cells by targeting specific antigens. However, the tumor microenvironment (TME), characterized by abnormal metabolism could inhibit CAR-T function. Therefore, the aim of this study was to improve CAR-T efficacy in solid TME by investigating the effects of amino acid metabolism. We found that B7H3 was highly expressed in LUSC and developed DAP12-CAR-T targeting B7H3 based on our previous findings. When co-cultured with B7H3-overexpressing LUSC cells, B7H3-DAP12-CAR-T showed significant cell killing effects and released cytokines including IFN-γ and IL-2. However, LUSC cells consumed methionine (Met) in a competitive manner to induce a Met deficiency. CAR-T showed suppressed cell killing capacity, reduced cytokine release and less central memory T phenotype in medium with lower Met, while the exhaustion markers were up-regulated. Furthermore, the gene NKG7, responsible for T cell cytotoxicity, was downregulated in CAR-T cells at low Met concentration due to a decrease in m5C modification. NKG7 overexpression could partially restore the cytotoxicity of CAR-T in low Met. In addition, the anti-tumor efficacy of CAR-T was significantly enhanced when co-cultured with SLC7A5 knockdown LUSC cells at low Met concentration. In conclusion, B7H3 is a prospective target for LUSC, and B7H3-DAP12-CAR-T cells are promising for LUSC treatment. Maintaining Met levels in CAR-T may help overcome TME suppression and improve its clinical application potential.

THOC3 interacts with YBX1 to promote lung squamous cell carcinoma progression through PFKFB4 mRNA modification.

The THO complex (THOC) is ubiquitously involved in RNA modification and various THOC proteins have been reported to regulate tumor development. However, the role of THOC3 in lung cancer remains unknown. In this study, we identified that THOC3 was highly expressed in lung squamous cell carcinoma (LUSC) and negatively associated with prognosis. THOC3 knockdown inhibited LUSC cell growth, migration, and glycolysis. THOC3 expression was regulated by TRiC proteins, such as CCT8 and CCT6A, which supported protein folding. Furthermore, THOC3 could form a complex with YBX1 to promote PFKFB4 transcription. THOC3 was responsible for exporting PFKFB4 mRNA to the cytoplasm, while YBX1 ensured the stability of PFKFB4 mRNA by recognizing m5C sites in its 3'UTR. Downregulation of PFKFB4 suppressed the biological activities of LUSC. Collectively, these findings suggest that THOC3, folded by CCT proteins can collaborate with YBX1 to maintain PFKFB4 expression and facilitate LUSC development. Therefore, THOC3 could be considered as a novel promising therapeutic target for LUSC.

Placenta-specific protein 1 promotes cell proliferation and invasion in non-small cell lung cancer.

Pulmonary carcinoma-associated proteins have emerged as crucial players in governing fundamental biological processes such as cell proliferation, apoptosis and metastasis in human cancers. Placenta-specific protein 1 (PLAC1) is a cancer-related protein, which is activated and upregulated in a variety of malignant tissues, including prostate cancer, gastric adenocarcinoma, colorectal, epithelial ovarian and breast cancer. However, its biological role and clinical significance in non-small cell lung cancer (NSCLC) development and progression are still unknown. In the present study, we found that PLAC1 was significantly upregulated in NSCLC tissues, and its expression level was associated with advanced pathological stage and it was also correlated with shorter progression-free survival of lung cancer patients. Furthermore, knockdown of PLAC1 expression by siRNA inhibited cell proliferation, induced apoptosis and impaired invasive ability in NSCLC cells partly via regulation of epithelial-mesenchymal transition (EMT)-related protein expression. Our findings present that increased PLAC1 could be identified as a negative prognostic biomarker in NSCLC and regulate cell proliferation and invasion. Thus, we conclusively demonstrated that PLAC1 plays a key role in NSCLC development and progression, which may provide novel insights on the function of tumor-related gene-driven tumorigenesis.

The pseudogene DUXAP10 promotes an aggressive phenotype through binding with LSD1 and repressing LATS2 and RRAD in non small cell lung cancer.

Pseudogenes have been considered as non-functional transcriptional relics of human genomic for long time. However, recent studies revealed that they play a plethora of roles in diverse physiological and pathological processes, especially in cancer, and many pseudogenes are transcribed into long noncoding RNAs and emerging as a novel class of lncRNAs. However, the biological roles and underlying mechanism of pseudogenes in the pathogenesis of non small cell lung cancer are still incompletely elucidated. This study identifies a putative oncogenic pseudogene DUXAP10 in NSCLC, which is located in 14q11.2 and 2398 nt in length. Firstly, we found that DUXAP10 was significantly up-regulated in 93 human NSCLC tissues and cell lines, and increased DUXAP10 was associated with patients poorer prognosis and short survival time. Furthermore, the loss and gain of functional studies including growth curves, migration, invasion assays and in vivo studies verify the oncogenic roles of DUXAP10 in NSCLC. Finally, the mechanistic experiments indicate that DUXAP10 could interact with Histone demethylase Lysine specific demethylase1 (LSD1) and repress tumor suppressors Large tumor suppressor 2 (LATS2) and Ras-related associated with diabetes (RRAD) transcription in NSCLC cells. Taken together, these findings demonstrate DUXAP10 exerts the oncogenic roles through binding with LSD1 and epigenetic silencing LATS2 and RRAD expression. Our investigation reveals the novel roles of pseudogene in NSCLC, which may serve as new target for NSCLC diagnosis and therapy.

Involvement of lncRNA dysregulation in gastric cancer.

Benefiting from the fast development of sequencing technique and bioinformatics methods, more and more new long non-coding RNAs (lncRNAs) are discovered and identified. lncRNAs were firstly thought to be transcription noise that from genome desert without biological function; however, as the discovery of lncRNA XIST and HOTAIR uncovers the emerging roles of lncRNAs in development and tumorigenesis. In the past decades, accumulating evidence have indicated that lncRNAs involve in a wide range of biological functions, such as X-chromosome inactivation, reprogramming stem cell pluripotency, regulation of the immune response and carcinogenesis. Although lots of studies have demonstrated that dysregulation of lncRNAs involve in diverse diseases including cancers, the underlying molecular mechanisms of lncRNAs are not well documented. Interestingly, our previous studies and others' have shown that numerous of lncRNAs expression was misregulated in gastric cancer. In this review, we will focus on the dysregulated lncRNAs and their biological function and underlying pathways or mechanisms in GC. Finally, we will discuss the potential roles of lncRNAs acting as biomarkers or therapeutic targets in GC patients.

Long non-coding RNA LINC01133 represses KLF2, P21 and E-cadherin transcription through binding with EZH2, LSD1 in non small cell lung cancer.

Long non-coding RNAs are emerging as crucial regulators and prognostic markers in multiple cancers including non small cell lung cancer (NSCLC). In this study, we screened LINCO1133 as a new candidate lncRNA which promotes NSCLC development and progression, in two independent datasets (GSE18842 and GSE19804) from the Gene Expression Omnibus (GEO). LINC01133 is previously found to be over-expressed in lung squamous cell cancer (LSCC) and knockdown its expression inhibits LSCC cells invasion. However, its' molecular mechanism and downstream targets involving in regulation of cancer cells phenotype is not known. Here, we found that LINC01133 expression is up-regulated in NSCLC tissues, and its' over-expression is associated with patients poor prognosis and short survival time. LINC01133 knockdown decreased NSCLC cells proliferation, migration, invasion and induced cell cycle G1/S phase arrest and cell apoptosis. Mechanistic investigations showed that LINC01133 could interact with EZH2, LSD1 and recruit them to KLF2, P21 or E-cadherin promoter regions to repress their transcription. Furthermore, rescue experiments demonstrated that LINC01133 oncogenic function is partly through regulating KLF2. Lastly, we found that there was negative correlation between LINC01133 and KLF2, P21 or E-cadherin in NSCLC. Overall, our findings illuminate how LINC01133 over-expression confers an oncogenic function in NSCLC that may offer a novel therapy target in this disease.

Long noncoding RNA ANRIL promotes non-small cell lung cancer cell proliferation and inhibits apoptosis by silencing KLF2 and P21 expression.

Recent evidence highlights long noncoding RNAs (lncRNA) as crucial regulators of cancer biology that contribute to essential cancer cell functions such as cell proliferation, apoptosis, and metastasis. In non-small cell lung cancer (NSCLC), several lncRNAs' expressions are misregulated and have been nominated as critical actors in NSCLC tumorigenesis. LncRNA ANRIL was first found to be required for the PRC2 recruitment to and silencing of p15(INK4B), the expression of which is induced by the ATM-E2F1 signaling pathway. Our previous study showed that ANRIL was significantly upregulated in gastric cancer, and it could promote cell proliferation and inhibit cell apoptosis by silencing of miR99a and miR449a transcription. However, its clinical significance and potential role in NSCLC is still not documented. In this study, we reported that ANRIL expression was increased in NSCLC tissues, and its expression level was significantly correlated with tumor-node-metastasis stages and tumor size. Moreover, patients with high levels of ANRIL expression had a relatively poor prognosis. In addition, taking advantage of loss-of-function experiments in NSCLC cells, we found that knockdown of ANRIL expression could impair cell proliferation and induce cell apoptosis both in vitro and vivo. Furthermore, we uncover that ANRIL could not repress p15 expression in PC9 cells, but through silencing of KLF2 and P21 transcription. Thus, we conclusively demonstrate that lncRNA ANRIL plays a key role in NSCLC development by associating its expression with survival in patients with NSCLC, providing novel insights on the function of lncRNA-driven tumorigenesis.