EYA2 suppresses the progression of hepatocellular carcinoma via SOCS3-mediated blockade of JAK/STAT signaling.

BACKGROUND: Somatic mutations are involved in hepatocellular carcinoma (HCC) progression, but the genetic mechanism associated to hepatocarcinogenesis remains poorly understood. We report that Eyes absent homolog 2 (EYA2) suppresses the HCC progression, while EYA2(A510E) mutation identified by exome sequencing attenuates the tumor-inhibiting effect of EYA2. METHODS: Whole-exome sequencing was performed on six pairs of human HCC primary tumors and matched adjacent tissues. Focusing on EYA2, expression level of EYA2 in human HCC samples was evaluated by quantitative real-time PCR, western blot and immunohistochemistry. Loss- and gain-of-function studies, hepatocyte-specific deletion of EYA2 (Eya2-/-) in mice and RNA sequencing analysis were used to explore the functional effect and mechanism of EYA2 on HCC cell growth and metastasis. EYA2 methylation status was evaluated using Sequenom MassARRAY and publicly available data analysis. RESULTS: A new somatic mutation p.Ala510Glu of EYA2 was identified in HCC tissues. The expression of EYA2 was down-regulated in HCC and associated with tumor size (P = 0.001), Barcelona Clinic Liver Cancer stage (P = 0.016) and tumor differentiation (P = 0.048). High level of EYA2 was correlated with a favorable prognosis in HCC patients (P = 0.003). Results from loss-of-function and gain-of-function experiments suggested that knockdown of EYA2 enhanced, while overexpression of EYA2 attenuated, the proliferation, clone formation, invasion, and migration of HCC cells in vitro. Delivery of EYA2 gene had a therapeutic effect on inhibition of orthotopic liver tumor in nude mice. However, EYA2(A510E) mutation led to protein degradation by unfolded protein response, thus weakening the inhibitory function of EYA2. Hepatocyte-specific deletion of EYA2 in mice dramatically promoted diethylnitrosamine-induced HCC development. EYA2 was also down-regulated in HCC by aberrant CpG methylation. Mechanically, EYA2 combined with DACH1 to transcriptionally regulate SOCS3 expression, thus suppressing the progression of HCC via SOCS3-mediated blockade of the JAK/STAT signaling pathway. CONCLUSIONS: In our study, we identified and validated EYA2 as a tumor suppressor gene in HCC, providing a new insight into HCC pathogenesis.

Basigin-2 upregulated by receptor activator of NF-κB ligand enhances lung cancer-induced osteolytic lesions.

BACKGROUND: Lung cancer bone metastasis causes poor prognosis. Basigin-2, a novel cancer-associated biomarker, is upregulated in lung cancer and has been linked with tumor progression. But little is known about the role of basigin-2 in lung cancer bone metastasis and osteolytic lesion. METHODS: Basigin-2 expression was evaluated in biopsy tissue specimens of 20 lung cancer patients with bone metastases via immunohistochemistry. Invasion assay and MTT proliferation assay were performed to test the invasion and proliferation of lung cancer cell after modulated basigin-2 expression. The osteoclastic activity of basigin-2 was detected in tibia cancer model by injected of lung cancer cells. The regulation role of receptor activator of NF-κB ligand (RANKL) on basigin-2 and its downstream molecules were measured by real-time quantitative RT-PCR, gelatin zymography and western blot analysis. RESULTS: We found that basigin-2 was highly expressed in lung cancer bone metastases. Then, we demonstrated that basigin-2 could promote lung cancer cells invasion, metastasis and proliferation through upregulating metalloproteinases-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF) expression. The lung cancer cells overexpressing basigin-2 strongly induced the osteolytic lesions in immunodeficient mice, which were reduced by treatment with basigin-2 blocking antibody. Furthermore, we explored the enhanced basigin-2 molecular mechanism in lung cancer bone metastasis. Our results indicated the RANKL, pivotal for the control of bone resorption, could increase basigin-2 and its downstream molecules MMP-2, MMP-9 and VEGF expression in vitro. CONCLUSIONS: Basigin-2 upregulated by RANKL induces MMPs and VEGF, which may increase lung cancer cell metastasis ability and support osteoclastic activity. Thus, our data suggest important roles for basigin-2 in lung cancer-induced osteolytic lesion and implicate this protein potential application as a target for lung cancer bone metastasis therapy.

miR-10b is overexpressed in hepatocellular carcinoma and promotes cell proliferation, migration and invasion through RhoC, uPAR and MMPs.

BACKGROUND: Recently, miR-10b is identified as a miRNA highly expressed in many human cancers, promoting cell migration and invasion. However, the specific function of miR-10b in hepatocellular carcinoma (HCC) is unclear at this point. METHODS: The miR-10b expression levels in 60 paired different TNM Stage HCC tumor tissues compared with adjacent non-tumor (ANT) tissues, normal tissue control (8 benign tumor and 7 normal liver tissues), 3 normal liver and 7 HCC cell lines were measured by real-time quantitative RT-PCR and to evaluate their association with HCC clinicopathologic features. Invasion assay, MTT proliferation assay and wound-healing assay were performed to test the invasion and proliferation of HCC cell after transfection. The effect of miR-10b on HCC in vivo was validated by murine xenograft model. RESULTS: We found that miR-10b expression was increased in human HCC tissues and cell lines compared with normal control, respectively. The expression of miR-10b was correlated with HCC metastatic ability. Overexpression of miR-10b in MHCC-97L cells increased cell motility and invasiveness, whereas inhibition of miR-10b in MHCC-97H cells reduced cell motility and invasiveness in vitro and in vivo. We also showed that HOXD10 was negatively regulated by miR-10b at the posttranscriptional level, via a specific target site within the 3'UTR by luciferase reporter assay. Furthermore, we found that miR-10b induced HCC cell invasion and migration by modulating the HOXD10 target gene RhoC, uPAR, MMP-2 and MMP-9 expression. CONCLUSIONS: Our results suggested that miR-10b was overexpressed in HCC and promoted HCC cell migration and invasion through the HOXD10/ RhoC/ uPAR/ MMPs pathway which may provide a novel bio-target for HCC therapy.

Causal Relationship Between Childhood Obesity and Sleep Apnea Syndrome: Bidirectional Two-Sample Mendelian Randomization Analysis.

Background: Childhood obesity has become a global pandemic, leading to a range of diseases. Childhood obesity appears to be associated with an increased prevalence of sleep apnea syndrome. Sleep apnea is an inestimable risk factor for thrombosis, hypertension, cardiomyopathy and many other diseases. Therefore, exploring the relationship between childhood obesity and sleep apnea syndrome will help to understand the potential link between the two and provide research directions for future disease prevention and treatment. However, no studies have confirmed whether there is a causal relationship between childhood obesity and sleep apnea syndrome. Methods: The IEU OpenGWAS project provided the GWAS-aggregated data for childhood obesity and sleep apnea syndrome. Inverse-variance weighted (IVW) was used as the main method to evaluate the causal relationship between childhood obesity and sleep apnea syndrome. Single nucleotide polymorphisms (SNPs) were regarded as instrumental variables, and the screening threshold was P <5.0×10-6. Leave-one-out method was performed to confirm the robustness of the results. Results: IVW analysis confirmed a causal relationship between genetic susceptibility to childhood obesity and an increased risk of sleep apnea syndrome [odds ratio (OR)=1.12, 95% confidence interval (CI): 1.02-1.23, P=0.016]. However, two-sample MR results also showed no causal relationship between genetic susceptibility to sleep apnea syndrome and an increased risk of childhood obesity (OR=1.50, 95% CI: 0.95-2.38, P=0.083). The intercept of MR-Egger regression was close to 0, which implies that there are no confounding factors in the analysis to affect the results of two-sample MR analysis. The leave-one-out results show that the bidirectional two-sample MR analysis results were robust. Conclusion: There is a causal relationship between genetic susceptibility to childhood obesity and increased risk of sleep apnea syndrome. People with a history of childhood obesity should pay more attention to physical examination to early prevention and management of sleep apnea syndrome.

HMMR alleviates endoplasmic reticulum stress by promoting autophagolysosomal activity during endoplasmic reticulum stress-driven hepatocellular carcinoma progression.

BACKGROUND: The mechanism of hepatitis B virus (HBV)-induced carcinogenesis remains an area of interest. The accumulation of hepatitis B surface antigen in the endoplasmic reticulum (ER) of hepatocytes stimulates persistent ER stress. Activity of the unfolded protein response (UPR) pathway of ER stress may play an important role in inflammatory cancer transformation. How the protective UPR pathway is hijacked by cells as a tool for malignant transformation in HBV-related hepatocellular carcinoma (HCC) is still unclear. Here, we aimed to define the key molecule hyaluronan-mediated motility receptor (HMMR) in this process and explore its role under ER stress in HCC development. METHODS: An HBV-transgenic mouse model was used to characterize the pathological changes during the tumor progression. Proteomics and transcriptomics analyses were performed to identify the potential key molecule, screen the E3 ligase, and define the activation pathway. Quantitative real-time PCR and Western blotting were conducted to detect the expression of genes in tissues and cell lines. Luciferase reporter assay, chromatin immunoprecipitation, coimmunoprecipitation, immunoprecipitation, and immunofluorescence were employed to investigate the molecular mechanisms of HMMR under ER stress. Immunohistochemistry was used to clarify the expression patterns of HMMR and related molecules in human tissues. RESULTS: We found sustained activation of ER stress in the HBV-transgenic mouse model of hepatitis-fibrosis-HCC. HMMR was transcribed by c/EBP homologous protein (CHOP) and degraded by tripartite motif containing 29 (TRIM29) after ubiquitination under ER stress, which caused the inconsistent expression of mRNA and protein. Dynamic expression of TRIM29 in the HCC progression regulated the dynamic expression of HMMR. HMMR could alleviate ER stress by increasing autophagic lysosome activity. The negative correlation between HMMR and ER stress, positive correlation between HMMR and autophagy, and negative correlation between ER stress and autophagy were verified in human tissues. CONCLUSIONS: This study identified the complicated role of HMMR in autophagy and ER stress, that HMMR controls the intensity of ER stress by regulating autophagy in HCC progression, which could be a novel explanation for HBV-related carcinogenesis.

Combining a CDK4/6 Inhibitor With Pemetrexed Inhibits Cell Proliferation and Metastasis in Human Lung Adenocarcinoma.

Background: Recent clinical trials of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in human lung adenocarcinoma (LUAD) have not achieved satisfactory results. The disappointing results of single-drug treatments have prompted studies about synergistic therapies of CDK4/6i with other drugs. We aimed to test the anti-tumor effect of ribociclib (a CDK4/6i) combined with pemetrexed on LUAD and the potential mechanisms. Methods: Cell lines were exposed to ribociclib and pemetrexed at different doses. Antitumor effects were measured using growth inhibition. Cell cycle distribution and apoptosis were evaluated using flow cytometry. Cell migration and invasion were measured using wound healing and transwell invasion assays, respectively. The expression levels of proteins were analyzed using western blotting. Mice xenograft models were used for validation in vivo. Results: Synergism was associated with a combination of cell cycle effects from both agents. Cell cycle analysis revealed that pemetrexed blocked cells in the S phase, whereas ribociclib arrested cells in the G1 phase. Concomitant treatment with pemetrexed and ribociclib resulted in a significantly stronger antitumor ability than treatment alone. We also found that ribociclib strongly enhanced the pro-apoptotic activity of pemetrexed via the caspase/bcl-2 signaling pathway. In addition, we report for the first time that combination treatment with ribociclib and pemetrexed significantly inhibits the migration and invasion of LUAD cells. Conclusions: Combining ribociclib and pemetrexed showed a powerful ability to inhibit cancer proliferation, invasion, and metastasis, and it holds potential as a novel effective combinative therapy for patients with LUAD.

Active demethylation upregulates CD147 expression promoting non-small cell lung cancer invasion and metastasis.

Non-small cell lung cancer (NSCLC) is a fatal disease, and its metastatic process is poorly understood. Although aberrant methylation is involved in tumor progression, the mechanisms underlying dynamic DNA methylation remain to be elucidated. It is significant to study the molecular mechanism of NSCLC metastasis and identify new biomarkers for NSCLC early diagnosis. Here, we performed MeDIP-seq and hMeDIP-seq analyses to detect the genes regulated by dynamic DNA methylation. Comparison of the 5mC and 5hmC sites revealed that the CD147 gene underwent active demethylation in NSCLC tissues compared with normal tissues, and this demethylation upregulated CD147 expression. Significantly high levels of CD147 expression and low levels of promoter methylation were observed in NSCLC tissues. Then, we identified the CD147 promoter as a target of KLF6, MeCP2, and DNMT3A. Treatment of cells with TGF-ß triggered active demethylation involving loss of KLF6/MeCP2/DNMT3A and recruitment of Sp1, Tet1, TDG, and SMAD2/3 transcription complexes. A dCas9-SunTag-DNMAT3A-sgCD147-targeted methylation system was constructed to reverse CD147 expression. The targeted methylation system downregulated CD147 expression and inhibited NSCLC proliferation and metastasis in vitro and in vivo. Accordingly, we used cfDNA to detect the levels of CD147 methylation in NSCLC tissues and found that the CD147 methylation levels exhibited an inverse relationship with tumor size, lymphatic metastasis, and TNM stage. In conclusion, this study clarified the mechanism of active demethylation of CD147 and suggested that the targeted methylation of CD147 could inhibit NSCLC invasion and metastasis, providing a highly promising therapeutic target for NSCLC.

Pyroptosis-Related LncRNA Signature Predicts Prognosis and Is Associated With Immune Infiltration in Hepatocellular Carcinoma.

Pyroptosis is an inflammatory form of programmed cell death that is involved in various cancers, including hepatocellular carcinoma (HCC). Long non-coding RNAs (lncRNAs) were recently verified as crucial mediators in the regulation of pyroptosis. However, the role of pyroptosis-related lncRNAs in HCC and their associations with prognosis have not been reported. In this study, we constructed a prognostic signature based on pyroptosis-related differentially expressed lncRNAs in HCC. A co-expression network of pyroptosis-related mRNAs-lncRNAs was constructed based on HCC data from The Cancer Genome Atlas. Cox regression analyses were performed to construct a pyroptosis-related lncRNA signature (PRlncSig) in a training cohort, which was subsequently validated in a testing cohort and a combination of the two cohorts. Kaplan-Meier analyses revealed that patients in the high-risk group had poorer survival times. Receiver operating characteristic curve and principal component analyses further verified the accuracy of the PRlncSig model. Besides, the external cohort validation confirmed the robustness of PRlncSig. Furthermore, a nomogram based on the PRlncSig score and clinical characteristics was established and shown to have robust prediction ability. In addition, gene set enrichment analysis revealed that the RNA degradation, the cell cycle, the WNT signaling pathway, and numerous immune processes were significantly enriched in the high-risk group compared to the low-risk group. Moreover, the immune cell subpopulations, the expression of immune checkpoint genes, and response to chemotherapy and immunotherapy differed significantly between the high- and low-risk groups. Finally, the expression levels of the five lncRNAs in the signature were validated by quantitative real-time PCR. In summary, our PRlncSig model shows significant predictive value with respect to prognosis of HCC patients and could provide clinical guidance for individualized immunotherapy.

Hepatic Artery Injection of 131I-Metuximab Combined with Transcatheter Arterial Chemoembolization for Unresectable Hepatocellular Carcinoma: A Prospective Nonrandomized, Multicenter Clinical Trial.

This prospective nonrandomized, multicenter clinical trial was performed to investigate the efficacy and safety of 131I-labeled metuximab in adjuvant treatment of unresectable hepatocellular carcinoma. Methods: Patients were assigned to treatment with transcatheter arterial chemoembolization (TACE) combined with 131I-metuximab or TACE alone. The primary outcome was overall tumor recurrence. The secondary outcomes were safety and overall survival. Results: The median time to tumor recurrence was 6 mo in the TACE + 131I-metuximab group (n = 160) and 3 mo in the TACE group (n = 160) (hazard ratio, 0.55; 95% CI, 0.43-0.70; P < 0.001). The median overall survival was 28 mo in the TACE + 131I-metuximab group and 19 mo in the TACE group (hazard ratio, 0.62; 95% CI, 0.47-0.82; P = 0.001). Conclusion: TACE + 131I-metuximab showed a greater antirecurrence benefit, significantly improved the 5-y survival of patients with advanced hepatocellular carcinoma, and was well tolerated by patients.

Promoter hypomethylation up-regulates CD147 expression through increasing Sp1 binding and associates with poor prognosis in human hepatocellular carcinoma.

CD147 is a transmembrane glycoprotein overexpressed in human hepatocellular carcinoma (HCC) which could promote HCC progression and metastasis. Promoter methylation is one of the most important processes in gene regulation. In this study, we aim to investigate CD147 promoter methylation status and the correlation with clinicopathological features and prognosis in HCC. CD147 promoter methylation statuses and expression levels in normal and HCC cell lines and 54 paired HCC and adjacent non-tumour (ANT) tissues were, respectively, examined by bisulphite genomic sequencing, methylation-specific PCR, real-time RT-PCR, Western blot and immunohistochemistry. The correlations of promoter methylation statuses with CD147 expression level and the clinicopathological features were statistically analysed in HCC patients. Significantly higher expression of CD147 and significantly lower promoter methylation level were observed in HCC cell lines compared to normal cell lines and tissues control. In vivo and in vitro analysis indicated that demethylation with 5-Aza-2'-deoxycytidine led to increased CD147 expression through enhancing Sp1 binding affinity, and methylation with methyltransferase reduced CD147 transcriptional activity through interfering Sp1 binding. CD147 promoter methylation level in HCC tissues (22.22%) was lower than that in ANT tissues (46.30%; P < 0.05). Within HCC tissues, a significant inverse correlation was observed between CD147 expression and methylation level (r=-0.615). Moreover, HCC patients with unmethylated CD147 promoter had a significantly higher recurrence rate (88.1%versus 58.3%; P < 0.05) and death rate (83.3%versus 50.0%; P < 0.05) than patients with methylated CD147 promoter. In conclusions, promoter hypomethylation up-regulates CD147 expression primarily through increasing Sp1 binding and associates with poor prognosis in HCC patients.

Transcription factor Sp1 regulates expression of cancer-associated molecule CD147 in human lung cancer.

CD147 is a novel cancer-associated biomarker that plays an important role in the invasion and metastasis of human lung cancer. In spite of its many known functions, little is known about CD147 transcriptional regulation. In this study, we explored the regulation of CD147 in human lung cancer tissues. Over 60% of the human lung cancer tissues expressed differential high levels of CD147. We then cloned the 5'-flanking region of the human CD147 gene and identified a critical promoter region at -108 to -42 which contained one binding site for Sp1, which was essential in up-regulating CD147 promoter activity. These results were proven by blocking Sp1 using RNAi or mithramycin A treatment and up-regulating Sp1 using transfection with eukaryotic expression vector. Consistent with the CD147 transcription activation, a high level of Sp1 expression was detected in lung cancer cell lines overexpressing CD147. Chromatin immunoprecipitation assay showed that much more Sp1 could bind to the CD147 promoter in 95-D with CD147 high expression than in SK-MES-1 with CD147 low expression. There was a significant positive correlation between CD147 expression and Sp1 expression level detected by immunohistochemistry (r = 0.831). Collectively, our results suggest that Sp1 is essential for regulating the CD147 gene expression in human lung cancer.

[Changes of NO2-/NO3- and nitration tyrosine concentrations in induced sputum of silicosis patients].

OBJECTIVE: To analyze the change in nitration tyrosine, NO(2)(-)/NO(3)(-)level in induced sputum of silicosis patients and dust exposure workers and to evaluate the approach and feasibility of nitric oxide (NO) metabolites as early detection indicators of silicosis. METHODS: Nitration tyrosine, NO(2)(-)/NO(3)(-)concentration in induced sputum of 80 dust exposure workers, 84 silicosis patients, 30 logistic personnel with no history of exposure to silica dust were determined and the relationship among Nitration tyrosine, NO(2)(-)/NO(3)(-)level and dust exposure years as well as pulmonary function tests were analyzed. RESULTS: NO(2)(-)/NO(3)(-)level among exposed group [60.30 (46.58) micromol/l] was significantly higher than the control group [36.90 (22.28) micromol/l], (P < 0.05), and the level of NO(2)(-)/NO(3)(-)among the cases [79.65 (89.10) micromol/l] was significantly higher than exposed group as well as the control group (P < 0.05). Compared with control, the level of nitration tyrosine in exposed group [3.51 (0.46) nmol/l] and the cases [3.48 (0.49) nmol/l] was significantly higher (P < 0.05). NO(2)(-)/NO(3)(-)level and dust exposure years were positively correlated (r = 0.3733 and 0.3830 respectively P < 0.05); NO(2)(-)/NO(3)(-)level and pulmonary function tests (FVC%, FEV1.0%, PEF%, MEF25%, MEF50%) were negatively correlated (r = 0.1540, 0.1723, 0.1535, 0.1485, 0.1643 respectively, P < 0.05). There was no correlation between nitration tyrosine and dust exposure years (P > 0.05), no correlation between nitration tyrosine and pulmonary function test (P > 0.05). CONCLUSION: The level of NO(2)(-)/NO(3)(-)level in induced sputum has a positive correlation with exposure to dust, suggesting that there will be a certain feasibility of the NO(2)(-)/NO(3)(-)as indicators of early detection of silicosis.

System analysis of the regulation of the immune response by CD147 and FOXC1 in cancer cell lines.

CD147, encoded by BSG, is a highly glycosylated transmembrane protein that belongs to the immunological superfamily and expressed on the surface of many types of cancer cells. While CD147 is best known as a potent inducer of extracellular matrix metalloproteinases, it can also function as a key mediator of inflammatory and immune responses. To systematically elucidate the function of CD147 in cancer cells, we performed an analysis of genome-wide profiling across the Cancer Cell Line Encyclopedia (CCLE). We showed that CD147 mRNA expression was much higher than that of most other genes in cancer cell lines. CD147 varied widely across these cell lines, with the highest levels in the ovary (COLO704) and stomach (SNU668), intermediate levels in the lung (RERFLCKJ, NCIH596 and NCIH1651) and lowest levels in hematopoietic and lymphoid tissue (UT7, HEL9217, HEL and MHHCALL3) and the kidney (A704 and SLR20). Genome-wide analyses showed that CD147 expression was significantly negatively correlated with immune-related genes. Our findings implicated CD147 as a novel regulator of immune-related genes and suggest its important role as a master regulator of immune-related responses in cancer cell lines. We also found a high correlation between the expression of CD147 and FOXC1, and proved that CD147 was a direct transcriptional target of FOXC1. Our findings demonstrate that FOXC1 is a novel regulator of CD147 and confirms its role as a master regulator of the immune response.

siRNA targeted against HAb18G/CD147 inhibits MMP-2 secretion, actin and FAK expression in hepatocellular carcinoma cell line via ERK1/2 pathway.

HAb18G/CD147 has been identified as a factor that induces MMPs production. SiRNA targeted against HAb18G/CD147 was transfected into FHCC-98 cells (a HCC cell line) to knockdown its expression. The results showed that downregulating HAb18G/CD147 decreased ERK1/2, MMP-2 and FAK levels and inhibited cell motility and invasion, together with rearranged actin stress fiber formation, while had no effects on integrin alpha3beta1 expression. MEK1/2 inhibitor, U0126, inhibited MMP-2, FAK and actin expression in FHCC-98 cell line. The findings indicate that si-HAb18G inhibits gelatinase production, actin and FAK expression in FHCC-98 via an ERK1/2 signaling pathway.

Transcription factor NF­YA promotes a malignant phenotype by upregulating fatty acid synthase expression.

Recent studies have revealed that increased expression of the alpha subunit of nuclear transcription factor Y (NF­YA) is associated with the malignant phenotype of various tumors. However, whether elevated expression of NF­YA promotes a malignant phenotype in osteosarcoma (OS), and the molecular mechanisms underlying this predicted effect is currently unknown. In the present study, small hairpin RNA (shRNA)­mediated knockdown of endogenous NF­YA significantly inhibited the migration and invasion capabilities of OS cells in vitro, whereas ectopic expression of NF­YA increased the migration and invasion capabilities of these cells. In addition, the induction of upregulated NF­YA expression on the malignant phenotype of OS cells was attenuated by silencing fatty acid synthase (FASN) expression. Furthermore, the expression level of FASN was increased by upregulating NF­YA, while decreased FASN expression was observed following NF­YA silencing in OS cells. The results of the present study suggest that NF­YA may promote a malignant phenotype in OS cells, in part, by activating the FASN signaling pathway, which may represent a promising target for the management of OS.

Interaction of KLF6 and Sp1 regulates basigin-2 expression mediated proliferation, invasion and metastasis in hepatocellular carcinoma.

Accumulating evidence suggests that the tumor suppressor gene Krüppel-like factor 6 (KLF6) plays important roles in both development and progression of cancer. However, the role of KLF6 in hepatocellular carcinoma (HCC) remains unclear. Cancer-related molecule basigin-2 plays an important role in HCC progression and metastasis. Sp1, one of Sp/KLFs family members, regulates basigin-2 expression in HCC. The involvement of KLFs in basigin-2 regulation and HCC progression and metastasis has not been investigated. We first measured KLF6 expression levels in 50 pairs of HCC and adjacent normal tissues (ANTs) by immunohistochemistry. Specifically, low KLF6 expression but high Sp1 and basigin-2 expression were found in HCC tissues. By contrast, the ANTs showed high KLF6 expression but low Sp1 and basigin-2 expression. Kaplan-Meier analysis showed that higher expression of KLF6 was associated with better overall survival. The survival rate of KLF6-negative patients was lower than that of KLF6-positive patients (P = 0.015). We also found that KLF6 binds to the basigin-2 and Sp1 promoters and decreases their expression. Thus, we identified a microcircuitry mechanism in which KLF6 can repress basigin-2 expression directly by binding to its promoter or indirectly by inhibiting the expression of the transcription factor Sp1 to block gene expression. Additionally, overexpression of KLF6 suppressed the invasion, metastasis and proliferation of HCC cells in vitro and in vivo by targeting basigin-2. Our study provides new evidence that interaction of KLF6 and Sp1 regulates basigin-2 expression in HCC and that KLF6 represses the invasive and metastatic capacities of HCC through basigin-2.

Activation of TGF-ß1-CD147 positive feedback loop in hepatic stellate cells promotes liver fibrosis.

Activation of hepatic stellate cells (HSCs) by transforming growth factor-ß1 (TGF-ß1) initiates HBV-associated fibrogenesis. The mechanism of TGF-ß1 modulating HSC activation is not fully uncovered. We hypothesized a positive feedback signaling loop of TGF-ß1-CD147 promoting liver fibrogenesis by activation of HSCs. Human HSC cell line LX-2 and spontaneous liver fibrosis model derived from HBV transgenic mice were used to evaluate the activation of molecules in the signaling loop. Wound healing and cell contraction assay were performed to detect the CD147-overexpressed HSC migration and contraction. The transcriptional regulation of CD147 by TGF-ß1/Smad4 was determined using dual-luciferase reporter assay and chromatin immunoprecipitation. We found that a positive reciprocal regulation between TGF-ß1 and CD147 mediated HSC activation. CD147 over-expression promoted HSC migration and accelerated TGF-ß1-induced cell contraction. Phosphorylation of Smad2 and Smad3 in cooperation with Smad4 mediated the TGF-ß1-regulated CD147 expression. Smad4 activated the transcription by direct interaction with CD147 promoter. Meanwhile, CD147 modulated the activated phenotype of HSCs through the ERK1/2 and Sp1 which up-regulated α-SMA, collagen I, and TGF-ß1 synthesis. These findings indicate that TGF-ß1-CD147 loop plays a key role in regulating the HSC activation and combination of TGF-ß receptor inhibitor and anti-CD147 antibody might be promised to reverse fibrogenesis.

A regulatory loop involving miR-22, Sp1, and c-Myc modulates CD147 expression in breast cancer invasion and metastasis.

Breast cancer is the most common cancer in women for which the metastatic process is still poorly understood. CD147 is upregulated in breast cancer and has been associated with tumor progression, but little is known about its regulatory mechanisms. In this study, we demonstrated that CD147 was overexpressed in breast cancer tissues and cell lines, and the high expression correlated with tumor invasion and metastasis. We also found that the transcription factors Sp1 and c-Myc could bind to the CD147 promoter and enhance its expression. The CD147 mRNA has a 748-bp 3'-untranslated region (UTR) with many miRNA target sites, suggesting possible regulation by miRNAs. We discovered that miR-22 repressed CD147 expression by directly targeting the CD147 3'UTR. We also determined that miR-22 could indirectly participate in CD147 modulation by downregulating Sp1 expression. miR-22 could form an autoregulatory loop with Sp1, which repressed miR-22 transcription by binding to the miR-22 promoter. Together with the c-Myc-mediated inhibition of miR-22 expression, our investigation identified a miR-22/Sp1/c-Myc network that regulates CD147 gene transcription. In addition, miR-22 overexpression suppressed breast cancer cell invasion, metastasis, and proliferation by targeting CD147 in vitro and in vivo. Furthermore, we found that miR-22 was significantly downregulated in breast cancer tissues and that its expression was inversely correlated with the tumor-node-metastasis stage and lymphatic metastasis in patients. Our study provides the first evidence that an miR-22/Sp1/c-Myc network regulates CD147 upregulation in breast cancer and that miR-22 represses breast cancer invasive and metastatic capacities.

Suppression of MMP-9 activity by NDRG2 expression inhibits clear cell renal cell carcinoma invasion.

Members of the NDRG (N-Myc downstream-regulated) gene family have been shown to play a variety of roles in human malignancies. Recently, it was shown decreased expression in clear cell renal cell carcinoma (CCRCC) and inhibited cell proliferation, but the role of the NDRG2 in CCRCC invasion has not been described. We examined the expression of NDRG2 protein in CCRCC samples and the association between NDRG2 expression and CCRCC patients survival. Real-time RT-PCR and immunohistochemical analysis were used to measure NDRG2 expression in 60 paired CCRCC and adjacent normal tissues. Changes in cell invasion were detected by up- or down-regulating NDRG2 by adenovirus or siRNA. We found that NDRG2 expression is significantly down-regulated in CCRCC at mRNA and protein levels in a manner negatively associated with aggressive tumor behaviors, such as TNM stage (P = 0.003), Fuhrman's grade (P = 0.024), tumor invasion (P = 0.001) and tumor recurrence (P = 0.004), as well as shorter patient survival rates (P = 0.0041). Furthermore, NDRG2 could suppress CCRCC cell invasion through regulating MMP-9 expression and activity. So, these results suggest that NDRG2 can inhibit extracellular matrix-based tumor cell invasion and thereby play important roles in suppressing tumor metastasis in CCRCC. NDRG2 expression may also be a significant prognostic indicator for CCRCC.