Insight into the molecular mechanism of LINC00152/miR-215/CDK13 axis in hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. Nevertheless, its underlying molecular mechanisms are largely unknown. LINC00152 are recently investigated in several cancer types. In our current investigation, we observed LINC00152 was obviously upregulated in HCC cells. LINC00152 was significantly downregulated by infecting LV-shLINC00152 in HepG2 and SNU449 cells. Loss of LINC00152 remarkably repressed HCC cell proliferation, cell colony formation, induced cell apoptosis, and restrained cell migration/invasion. Growing evidence has reported long noncoding RNAs can sponge microRNAs to modulate cancer process. Here, we indicated miR-215 was greatly decreased in HCC and LINC00152 regulated HCC development via sponging miR-215. For another, the binding association between LINC00152 and miR-215 was proved by a series of functional assays. CDK13 was predicted as the target of miR-215. Upregulation of miR-215 greatly depressed CDK13 in HCC cells. Subsequently, the in vivo results demonstrated that silence of LINC00152 restrained HCC development via modulating miR-215 to up-regulate CDK13. Therefore, it was revealed that LINC00152 contributed to the progression of HCC by the modulation of miR-215 and CDK13.     

LINC00707 promotes hepatocellular carcinoma progression through activating ERK/JNK/AKT pathway signaling pathway

Increasing evidence has demonstrated that abnormal expression of lncRNA is correlated with various malignant tumors, including hepatocellular carcinoma (HCC). Our current study was aimed to investigate the role of LINC00707 in HCC development. We observed that LINC00707 was upregulated in HCC cell lines compared with normal liver cell lines. Then, Hep3B cells and SNU449 cells were infected with LV-shLINC00707 and LV-LINC00707. LINC00707 silencing could greatly repress the proliferation and colony formation of HCC cells in vitro. On the contrary, overexpression of LINC00707 induced HCC cell proliferation and colony formation. In addition, HCC cell apoptosis was significantly enhanced and HCC cell cycle was blocked in G1 phase by LV-shLINC00707. Hep3B cells and SNU449 cell invasion capacity was restrained by the knockdown of LINC00707, whereas upregulation of LINC00707 exhibited an opposite phenomenon. Accumulating evidence has reported that ERK/JNK/AKT signaling is involved in multiple cancers, including HCC. Here, in our study, we identified that ERK/JNK/AKT signaling was dramatically restrained by silencing of LINC00707 while activated by LV-LINC00707 in HCC cells. Subsequently, an in vivo experiment was conducted, and it demonstrated that LINC00707 could modulate HCC development through activating ERK/JNK/AKT signaling. Taking the above results together, it was implied in our study that LINC00707 contributed to HCC progression through modulating the ERK/JNK/AKT pathway.     

LINC01133 aggravates the progression of hepatocellular carcinoma by activating the PI3K/AKT pathway

LncRNAs exhibit crucial roles in various pathological diseases, including hepatocellular carcinoma (HCC). Therefore, it is significant to recognize the dysregulated lncRNAs in HCC progression. Recently, LINC01133 has been identified in several tumors. However, the biological role of LINC01133 in HCC remains poorly understood. Currently, we focused on the function of LINC01133 in HCC development. We observed that LINC01133 was significantly increased in HCC cells including HepG2, Hep3B, MHCC-97L, SK-Hep-1, and MHCC-97H cells compared with the normal human liver cell line HL-7702. In addition, PI3K/AKT signaling was highly activated in HCC cells. Knockdown of LINC01133 was able to inhibit HCC cell proliferation, cell colony formation, cell apoptosis, and blocked cell cycle arrest in the G1 phase. For another, downregulation of LINC01133 repressed HCC cell migration and invasion. Subsequently, the PI3K/AKT signaling pathway was strongly suppressed by silence of LINC01133 in Hep3B and HepG2 cells. Then, in vivo tumor xenografts models were established using Hep3B cells to explore the function of LINC01133 in HCC progression. Consistently, our study indicated that knockdown of LINC01133 dramatically repressed HCC tumor progression through targeting the PI3K/AKT pathway in vivo. Taken these together, we revealed that LINC01133 contributed to HCC progression by activating the PI3K/AKT pathway.     

Retracted: LINC00707 contributes to hepatocellular carcinoma progression via sponging miR-206 to increase CDK14

Recently, increasing numbers of long noncoding RNAs (lncRNAs) have been found to be aberrantly expressed in various cancers. However, the roles of lncRNAs in hepatocellular carcinoma (HCC) progression is largely unknown. In our current study, we identified that long intergenic nonprotein-coding RNA 707 (LINC00707) was remarkably elevated in HCC cells, indicating that LINC00707 was involved in HCC development. Subsequently, LINC00707 was significantly decreased in HepG2 and Huh7 cells. The in vitro functional assays demonstrated that knockdown of LINC00707 significantly reduced HCC cell proliferation, induced cell apoptosis, and blocked the cell cycle progression. In addition, HCC cell migration and invasion was also greatly inhibited by downregulation of LINC00707. Increasing evidence has indicated that lncRNAs can act as molecular sponges of microRNAs. Currently, we observed that microRNA-206 (miR-206) was dramatically inhibited in HCC cells and LINC00707 can modulate HCC development through sponging miR-206. The binding correlation between LINC00707 and miR-206 was confirmed by dual-luciferase reporter assay, RNA pull down and RNA immunoprecipitation assay in our study. Moreover, cyclin-dependent kinase 14 (CDK14) was predicted as a target of miR-206 and we found that miR-206 suppressed CDK14 levels in HCC cells. Finally, in vivo assays were used and it was proved that silence of LINC00707 can restrain HCC development through modulating miR-206 to upregulate CDK14. In conclusion, it was implied that LINC00707 can lead to HCC progression through sponging miR-206 and modulating CDK14.     

Overexpression of LINC00037 represses cervical cancer progression by activating mTOR signaling pathway

Long non-coding RNAs have been reported to play crucial roles in tumorigenesis including cervical cancer. LINC00037 has been identified as a significant regulator in several cancers. Our study was aimed to investigate the function of LINC00037 in cervical cancer progression. LINC00037 was significantly downregulated in human cervical cancer cells (HeLa, HCC94, HT-3, Caski, and SiHa cells) compared with the ectocervical epithelial cells (End1/E6E7 cells). Overexpression of LINC00037 was able to inhibit cervical cancer cell proliferation, induce cell apoptosis, and restrain the cell migration/invasion capacity. Reversely, knockdown of LINC00037 exhibited an opposite process in vitro. mTOR has been recognized as an atypical serine/threonine kinase that is involved in regulating significant cellular functions. In our present study, we observed that the mTOR signaling pathway was strongly activated in human cervical cancer cells. Meanwhile, upregulation of LINC00037 contributed to the inactivation of mTOR signaling whereas downregulation of LINC00037 activated the pathway. Subsequently, in vivo animal models using SiHa cells were established and we proved that LINC00037 repressed cervical cancer progression via targeting the mTOR signaling pathway. All these findings implied that LINC00037 could regulate cervical cancer pathogenesis via mTOR signaling. In conclusion, a novel role of LINC00037 was manifested in cervical cancer progression.     

LncRNA DGCR5 represses the development of hepatocellular carcinoma by targeting the miR-346/KLF14 axis

Long non-coding RNAs (lncRNAs) are a class of regulatory noncoding RNAs. Emerging evidence highlights the critical roles of lncRNAs in the progression of hepatocellular carcinoma (HCC). Although many lncRNAs have been identified in the development of HCC, the association between DiGeorge syndrome critical region gene 5 (DGCR5) and HCC remains unclear. In the current study, we focused on the biological role of DGCR5 in HCC. We observed that DGCR5 was decreased in HCC cells, including SMCC7721, Hep3B, HepG2, MHCC-97L, MHCC-97H, and SNU449 hepatocellular carcinoma cells, compared with the normal human liver cell line THLE-3 normal human liver cells. In addition, DGCR5 overexpression could repress HCC cell growth, migration, and invasion considerably. Increasing studies have indicated the interactions between lncRNAs and microRNAs. MicroRNAs are endogenous small noncoding RNAs and they can play important roles in tumorigenesis. MicroRNA 346 (miR-346) has been demonstrated in various human cancer types, including HCC. MiR-346 was found to be increased in HCC cells and DGCR5 can act as a sponge of miR-346 to modulate the progression of HCC. The binding correlation between DGCR5 and miR-346 was validated in our research. Subsequently, Krüppel-like factor 14 (KLF14) was predicted as a downstream target of miR-346 and miR-346 can induce the development of HCC by inhibiting KLF14. Finally, we proved that DGCR5 can rescue the inhibited levels of KLF14 repressed by miR-346 mimics in MHCC-97H and Hep3B cells. Taken together, it was indicated in our study that DGCR5 can restrain the progression of HCC through sponging miR-346 and modulating KLF14 in vitro.     

LINC01433 promotes hepatocellular carcinoma progression via modulating the miR-1301/STAT3 axis

Long noncoding RNAs (lncRNAs) have been demonstrated to play significant roles in hepatocellular carcinoma (HCC) tumor progression. LINC01433 has been implicated in the progression of lung cancer. However, its biological role in HCC remains poorly understood. In our current study, we focused on the detailed mechanism of LINC01433 in HCC development. First, it was exhibited that LINC01433 was remarkably elevated in HCC cells, which indicated that LINC01433 was involved in HCC. Then, knockdown of LINC01433 was able to restrain HCC cell proliferation and cell colony formation and greatly induced cell apoptosis. On the contrary, overexpression of LINC01433 promoted HCC cell proliferation, increased cell colony formation, and enhanced cell invasion capacity. Subsequently, we found that miR-1301 was remarkably decreased in HCC cells, and it can serve as a target of LINC01433 according to bioinformatics analysis. In addition, the binding correlation between them was validated by performing RNA pull-down experiments and RIP assay. Moreover, STAT3 was predicted and validated as a target of miR-1301, and it was shown that miR-1301 mimics significantly suppressed STAT3 in HCC cells. Finally, in vivo models were established, and the results demonstrated that silencing of LINC01433 could repress HCC development through modulating miR-1301 and STAT3. Taken together, these results indicated in our study that LINC01433 participated in HCC progression through modulating the miR-1301/STAT3 axis and it might act as a novel biomarker in HCC diagnosis and treatment.     

LINC00665 induces gastric cancer progression through activating Wnt signaling pathway

Long noncoding RNAs (lncRNAs) are recently recognized as noteworthy regulators of different tumors, counting gastric cancer (GC). Lately, long intergenic noncoding RNA (LINC) 00665 has been verified to display significant parts in several cancers. Be that as it may, its role and mechanism in GC movement still stay uninvestigated. As of now, we observed LINC00665 was obviously GC cells (MKN28, BGC-823, SGC7-901, AGS, HGC-27) in comparison to GES-1 cells, which was identified as human normal gastric epithelial cells. Then, LINC00665 was obviously downregulated in GC cells including AGS and BGC-823 cells. Loss of LINC00665 greatly repressed AGS and BGC-823 cell survival and cell expansion. Moreover, GC cell apoptosis was significantly induced by the loss of LINC00665. For another, we found that the GC cell cycle was also captured in G1 and G2 phases. The experiments on cell migration and invasion indicated that knockdown of LINC00665 restrained GC cell migration and invasion. Modifications in Wnt signaling are closely associated with the development of cancers. Here, we found that Wnt signaling was significantly inactivated by the silence of LINC00665 in GC cells. β-catenin and cyclinD1 were restrained whereas GSK-3β was induced by the inhibition of LINC00665 in GC cells. Furthermore, we confirmed the impact of LINC00665 in vivo using xenograft models. Taken these together, we indicated that LINC00665 could function as a novel biomarker in GC progression.     

LINC00052 functions as a tumor suppressor through negatively modulating miR-330-3p in pancreatic cancer

Pancreatic cancer is a serious solid malignant tumor worldwide. Increasing evidence has pointed out that abnormal expressions of long noncoding RNAs are involved in various tumors. Meanwhile, LINC00052 is reported as a famous tumor regulator in several cancers. Nevertheless, the biological role of LINC00052 in pancreatic cancer progression is still unknown. Our study was to explore the specific mechanism of LINC00052 in pancreatic cancer. First, we observed that the LINC00052 was obviously downregulated in several pancreatic cancer cell lines. Overexpression of LINC00052 greatly repressed AsPC-1 and SW1990 cell proliferation, triggered the apoptosis and prevented cell cycle in the G1 phase. For another, AsPC-1 and SW1990 cell migration and invasion capacity were also obviously repressed by LINC00052 upregulation. Moreover, miR-330-3p was elevated in pancreatic cancer cells and can function as a target of LINC00052 confirmed by luciferase reporter and RNA Immunoprecipitation (RIP) experiments. Inhibition of miR-330-3p could depress pancreatic cancer progression while overexpressed miR-330-3p exhibited an opposite process. Finally, our data indicated that the LINC00052 also remarkably suppressed pancreatic tumor growth via modulating miR-330-3p in vivo. To conclude, our study revealed that the LINC00052 might provide a new perspective for pancreatic cancer therapy.     

LINC00628 suppresses migration and invasion of hepatocellular carcinoma by its conserved region interacting with the promoter of VEGFA

Accumulated evidence revealed that numerous long noncoding RNAs (lncRNAs) have been found to be involved in the development and progression of hepatocellular carcinoma (HCC). LINC00628, a member of lncRNAs, has been reported to act as a tumor suppressor in gastric cancer and breast cancer. However, its potential role in HCC still remains unknown. Herein, we characterized the function of LINC00628 in HCC. Our investigation has revealed that LINC00628 were dramatically decreased in HCC tissues and cells, and inhibited the migration and invasion of HCC cells in vitro and in vivo. Moreover, LINC00628 exerted its tumor suppressive function by repressing the vascular endothelial growth factor A (VEGFA) promoter activity. A highly conserved region element in LINC00628 was identified by a cross-species comparative analysis, which is required for LINC00628 exerted its function. Dual-luciferase reporter assay showed that the conserved sequence mediated the interaction with a specific region of VEGFA promoter, resulting in a decrease of VEGFA expression. In conclusion, our results demonstrated that LINC00628 could function as a tumor suppressor in HCC via its conserved sequence elements interacting with a particular region of VEGFA promoter, suggesting that LINC00628 may serve as a novel promising target for diagnosis and therapy in HCC.     

Long non-coding RNA 657 suppresses hepatocellular carcinoma cell growth by acting as a molecular sponge of miR-106a-5p to regulate PTEN expression

Previous study has identified the aberrant expression of LINC00657, a long non-coding RNA (lncRNA), in human breast cancer. However, the expression pattern, biological function and underlying mechanism of LINC00657 in human hepatocellular carcinoma (HCC) remain obscure. The expression levels of LINC00657 in HCC tissues and cell lines were determined by quantitative real-time PCR. CCK-8 assay, cell colony formation assay, cell cycle analysis, Transwell assay were performed to determine whether LINC00657 could affect HCC progression. Luciferase reporter assay was used to assess the target of LINC00657. Expressions of the relevant proteins were analyzed by Western blot. Herein, we found that LINC00657 was downregulated in HCC tissue specimens as well as in malignant HCC cell lines. LINC00657 overexpression inhibited the proliferation, migration and invasion of HCC cells, while LINC00657 depletion promoted both cell viability and cell invasion in vitro. We also found that LINC00657 could inhibit tumor growth in vivo. Further experiments demonstrated that down-regulated LINC00657 increased the expression of miR-106a-5p. miR-106a-5p decreased the abundances of PTEN protein, while had no impact on PTEN mRNA. Moreover, we identified that both LINC00657 and PTEN mRNA were targets of miR-106a-5p by using dual-luciferase reporter assay. Our results provide the new evidence supporting the tumor-suppressive role of LINC00657 in HCC, suggesting that LINC00657 might play a role in HCC and can be a novel therapeutic target for treating HCC.     

LINC00261 suppresses human colon cancer progression via sponging miR-324-3p and inactivating the Wnt/β-catenin pathway

Growing evidence indicates long noncoding RNAs (lncRNAs) are significant regulators in the progression of various malignant tumors including colon cancer. Dysregulation of lncRNA LINC00261 has been identified in many cancers. Investigations on LINC00261 function have revealed that LINC00261 could act as a crucial tumor suppressor in various cancers. But, the biological involvement of LINC00261 in colon cancer is still barely known. Here, we found LINC00261 was reduced in colon cancer cells. Meanwhile, overexpressed LINC00261 repressed colon cancer cell viability and proliferation capacity. In addition, colony cancer cell colony formation was inhibited and apoptosis was enhanced by upregulation of LINC00261. Also, colon cancer cell migration and invasion both were restrained by LINC00261. miR-324-3p can exert important functions in several carcinomas, but its role in colon cancer is uninvestigated. In the current study, miR-324-3p was examined and miR-324-3p was greatly increased in colon cancer cells. Moreover, the association between miR-324-3p and LINC00261 was confirmed via performing RNA immunoprecipitation and RNA-pull-down experiments. In cancer biology, aberrant modulation of the Wnt signaling pathway remains a prevalent theme. Overexpression of LINC00261 obviously impaired colon cancer progression via inactivating the Wnt pathway. Furthermore, in the xenograft model assay, an increase of LINC00261 could suppress colon tumor growth via sponging miR-324-3p and inactivating the Wnt pathway. Overall, our results showed that LINC00261 repressed colon cancer progression via regulating miR-324-3p and the Wnt pathway. LINC00261 could be established as a novel therapeutic target for colon cancer.     

miR-199a-3p targets CD44 and reduces proliferation of CD44 positive hepatocellular carcinoma cell lines

Previous work by us and others reported decreased expression of miR-199a-3p in hepatocellular carcinoma (HCC) tissues compared to adjacent benign tissue. We report here a significant reduction of miR-199a-3p expression in 7 HCC cell lines. To determine if miR-199a-3p has a tumor suppressive role, pre-miR-199a-3p oligonucleotides were transfected into the HCC cell lines. Pre-miR-199a-3p oligonucleotide reduced cell proliferation by approximately 60% compared to control oligonucleotide in only two cell lines (SNU449 and SNU423); the proliferation of the other 5 treated cell lines was similar to control oligonucleotide. A pre-miR-199a-3p oligonucleotide formulated with chemical modifications to enhance stability while preserving processing, reduced cell proliferation in SNU449 and SNU423 to the same extent as the commercially available pre-miR-199a-3p oligonucleotide. Furthermore, only the duplex miR-199a-3p oligonucleotide, and not the guide strand alone, was effective at reducing cell viability. Since a CD44 variant was essential for c-Met signaling [V. Orian-Rousseau, L. Chen, J.P. Sleeman, P. Herrlich, H. Ponta, CD44 is required for two consecutive steps in HGF/c-Met signaling, Genes Dev. 16 (2002) 3074-3086] and c-Met is a known miR-199a-3p target, we hypothesized that miR-199a-3p may also target CD44. Immunoblotting confirmed that only the two HCC lines that were sensitive to the effects of pre-miR-199a-3p were CD44+. Direct targeting of CD44 by miR-199a-3p was confirmed using luciferase reporter assays and immunoblotting. Transfection of miR-199a-3p into SNU449 cells reduced in vitro invasion and sensitized the cells to doxorubicin; both effects were enhanced when hyaluronic acid (HA) was added to the cell cultures. An inverse correlation between the expression of miR-199a-3p and CD44 protein was noted in primary HCC specimens. The ability of miR-199a-3p to selectively kill CD44+ HCC may be a useful targeted therapy for CD44+ HCC.     

Small regulatory polypeptide of amino acid response negatively relates to poor prognosis and controls hepatocellular carcinoma progression via regulating microRNA-5581-3p/human cardiolipin synthase 1

Hepatocellular carcinoma (HCC) is one of the most common malignancies with extremely high rates of occurrence and death. Long noncoding RNAs (lncRNAs) have been increasingly revealed to participate in tumorigenesis and development of multiple human cancers, including HCC. LINC00961 is a novel lncRNA which has been uncovered as a tumor suppressor in lung cancer and glioma. However, the role of LINC00961 in HCC has never been probed yet. Herein, we revealed a marked downregulation of LINC00961 in HCC tissues and cell lines. Correlation of low LINC00961 expression with poor outcomes in patients with HCC suggested LINC00961 as an independent predictor for HCC prognosis. Functionally, LINC00961 overexpression obviously inhibited cell proliferation, migration, and invasion in HCC cells. Mechanistically, LINC00961 regulated cardiolipin synthase 1 (CRLS1) expression via sponging miR-5581-3p. Importantly, both miR-5581-3p upregulation and CRLS1 inhibition led to an acceleration in cellular processes in HCC cells. At length, the rescue assays suggested that LINC00961 functioned in HCC through the miR-5581-3p/CRLS1 axis. On the whole, our findings disclosed that LINC00961 played a suppressive role in HCC progression via modulating miR-5581-3p/CRLS1, thus providing a potentially effective target for the prognosis and treatment of patients with HCC.     

Long noncoding RNA LINC00629 restrains the progression of gastric cancer by upregulating AQP4 through competitively binding to miR-196b-5p

Gastric cancer continues to be a common cancer in the world with high incidence and mortality. Accumulating evidence has implicated long noncoding RNAs (lncRNAs) in gastric cancer progression. Here, this study identified the potential role of a novel lncRNA, LINC00629 in gastric cancer and to elucidate the underlying mechanism. Initially, microarray-based gene expression profiling of gastric cancer was employed to identify differentially expressed genes. Next, the expression of LINC00629, microRNA-196b-5p (miR-196b-5p) and aquaporin 4 (AQP4) in clinical gastric cancer tissues was determined and the cell line presenting with the lowest LINC00629 expression was selected. The interaction among LINC00629, miR-196b-5p, and AQP4 was identified. Expression of LINC00629, miR-196b-5p, and AQP4 in gastric cancer cells were altered and then biological behaviors of gastric cancer cells were assessed by 5-ethynyl-2′-deoxyuridine and Transwell assays. Tumor formation in vivo was evaluated in nude mice. In gastric cancer, expression of LINC00629 and AQP4 was downregulated, and expression of miR-196b-5p was upregulated. Proliferation, invasion, and migration of gastric cancer cells were reduced after overexpression of LINC00629. LINC00629 competitively bound to miR-196b-5p, while AQP4 was a target of miR-196b-5p. Either downregulating miR-196b-5p or upregulating AQP4 could restrain the development of gastric cancer in vitro. LINC00629 overexpression repressed the growth of transplanted tumors in vivo. Taken together, LINC00629 competitively bound to miR-196b-5p to upregulate AQP4 expression, thereby inhibiting gastric cancer progression. Therefore, understanding of this mechanism may help to improve gastric cancer treatment.     

LINC00152 promotes cell cycle progression in hepatocellular carcinoma via miR-193a/b-3p/CCND1 axis

Long intergenic non-coding RNA 00152 (LINC00152) is aberrantly expressed in various human malignancies and plays an important role in the pathogenesis. Here, we found that LINC00152 is upregulated in hepatocellular carcinoma (HCC) tissues as compared to adjacent non-neoplastic tissues; gain-and-loss-of-function analyses in vitro showed that LINC00152 facilitates HCC cell cycle progression through regulating the expression of CCND1. LINC00152 knockdown inhibits tumorigenesis in vivo. MS2-RIP analysis indicated that LINC00152 binds directly to miR-193a/b-3p, as confirmed by luciferase reporter assays. Furthermore, ectopic expression of LINC00152 partially halted the decrease in CCND1 expression and cell proliferation capacity induced by miR-193a/b-3p overexpression. Thus, LINC00152 acts as a competing endogenous RNA (ceRNA) by sponging miR-193a/b-3p to modulate its target gene, CCND1. Our findings establish a ceRNA mechanism regulating cell proliferation in HCC via the LINC00152/miR-193a/b-3p/CCND1 signalling axis, and identify LINC00152 as a potential therapeutic target for HCC.