Rock2 regulates Cdc25A through ubiquitin proteasome system in hepatocellular carcinoma cells

Understanding the molecular pathway of triclosan-induced ADHD-like behaviour: Involvement of the hnRNPA1-PKM2-STAT3 feedback loop

Triclosan (TCS) is an environmental pollutant. In recent years, there has been increasing level of concern regarding the potential toxicity of TCS in animals and humans, especially its effects on the nervous system. However, whether TCS induces ADHD-like behaviour and the mechanism by which it affects neural function are unclear. The impact of 60 days of continuous exposure to TCS on the behaviour of offspring rats was assessed in this research. According to the results of this study, TCS exposure led to ADHD-like behaviour in offspring rats and activated microglia in the prefrontal cortex (PFC), inducing inflammatory factor release. In vitro studies showed that TCS increased the levels of inflammatory cytokines, including interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-α, in HMC3 cells. More importantly, we found that TCS regulated the STAT3 pathway by upregulating PKM2 via hnRNPA1. In summary, this study suggested that TCS can induce ADHD-like behaviour in offspring rats and continuously activate HMC3 microglia through the hnRNPA1-PKM2-STAT3 feedback loop, promoting inflammatory cytokine secretion.

Ginsenoside 20(S)-Rg3 reduces KIF20A expression and promotes CDC25A proteasomal degradation in epithelial ovarian cancer

Background

Ginsenoside 20(S)-Rg3 shows promising tumor-suppressive effects in ovarian cancer via inhibiting NF-κB signaling. This study aimed to explore the downstream tumor suppressive mechanisms of ginsenoside Rg3 via this signaling pathway.

Materials and methods

A systematical screening was applied to examine the expression profile of 41 kinesin family member genes in ovarian cancer. The regulatory effect of ginsenoside Rg3 on KIF20A expression was studied. In addition, we explored interacting proteins of KIF20A and their molecular regulations in ovarian cancer. RNA-seq data from The Cancer Genome Atlas (TCGA) was used for bioinformatic analysis. Epithelial ovarian cancer cell lines SKOV3 and A2780 were used as in vitro and in vivo cell models. Commercial human ovarian cancer tissue arrays were used for immunohistochemistry staining.

Results

KIF20A is a biomarker of poor prognosis among the kinesin genes. It promotes ovarian cancer cell growth in vitro and in vivo. Ginsenoside Rg3 can suppress the transcription of KIF20A. GST pull-down and co-immunoprecipitation (IP) assays confirmed that KIF20A physically interacts with BTRC (β-TrCP1), a substrate recognition subunit for SCFβ-TrCP E3 ubiquitin ligase. In vitro ubiquitination and cycloheximide (CHX) chase assays showed that via interacting with BTRC, KIF20A reduces BTRC-mediated CDC25A poly-ubiquitination and enhances its stability. Ginsenoside Rg3 treatment partly abrogates KIF20A overexpression-induced CDC25A upregulation.

Conclusion

This study revealed a novel anti-tumor mechanism of ginsenoside Rg3. It can inhibit KIF20A transcription and promote CDC25A proteasomal degradation in epithelial ovarian cancer.

Identification of a Novel Survival-Related circRNA–miRNA–mRNA Regulatory Network Related to Immune Infiltration in Liver Hepatocellular Carcinoma

Increasing studies have reported that circular RNAs (circRNAs) play critical roles in tumorigenesis and cancer progression. However, the underlying regulatory mechanisms of circRNA-related competing endogenous RNA (ceRNA) in liver hepatocellular carcinoma (LIHC) are still unclear. In the present study, we discovered dysregulated circRNAs through Gene Expression Omnibus (GEO) analysis and validated the expression of the top seven circRNAs with upregulated expression by qRT–PCR and Sanger sequencing. Then, the Cancer-Specific CircRNA Database (CSCD) was used to predict the downstream miRNAs of seven circRNAs, and expression and survival analyses through The Cancer Genome Atlas (TCGA) were performed to identify the key miRNA in LIHC. Thereafter, the hsa_circ_0017264-hsa-miR-195–5p subnetwork was successfully constructed. Subsequently, we predicted downstream target genes of hsa-miR-195–5p with TargetScan, miRDB, and mirtarbase and overlapped them with differentially expressed mRNAs to obtain 21 target genes. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to predict the biological and functional roles of these target genes. Finally, with Pearson correlation and prognostic value analysis, a survival-related hsa_circ_0017264-hsa-miR-195-5p-CHEK1/CDC25A/FOXK1 axis was established. Gene set enrichment analysis (GSEA) was performed to determine the function of CHEK1/CDC25A/FOXK1 in the ceRNA network. Moreover, immune infiltration analysis revealed that the ceRNA network was markedly associated with the levels of multiple immune cell infiltrates, immune cell biomarkers and immune checkpoints. Overall, the hsa_circ_0017264-hsa-miR-195-5p-CHEK1/CDC25A/FOXK1 network might provide novel insights into the potential mechanisms underlying LIHC onset and progression.

USP18 promotes tumor metastasis in esophageal squamous cell carcinomas via deubiquitinating ZEB1

The dysregulation of deubiquitinating enzymes (DUBs), which regulate the stability of most cellular proteins, have been implicated in many human diseases, including cancers. Ubiquitin-specific protease 18 (USP18), a member of the DUBs family, functions as a potential tumour promoter in various cancers. However, the biological function and clinical significance of USP18 in esophageal squamous cell carcinomas (ESCC) are still unclear. Here, we found that ESCC tumors had higher USP18 expression compared with that of normal esophageal epithelial tissues, and high USP18 level was significantly correlated with malignant phenotype and shorter survival in patients with ESCC. In functional experiments, USP18 knockdown significantly inhibited ESCC invasion and metastasis in vitro. Consistently, a xenograft assay showed that knockdown of USP18 in ESCC cell suppressed their dissemination to lung tissue in vivo. Furthermore, we showed that USP18 promoted ESCC cell metastasis by inducing ZEB1 mediated epithelial-mesenchymal transition (EMT). Importantly, our results demonstrated that the oncogenic effect of USP18 in ESCC is partially dependent on ZEB1 enhancement. Mechanistic investigations revealed that USP18 directly bound ZEB1 and decreased its ubiquitination to enhance the protein stability of ZEB1 in ESCC cells. Overall, our data highlighted an essential role of USP18 in ESCC metastasis, suggesting that it could be a potential diagnostic and therapeutic target for ESCC.

Mir-21 Suppression Promotes Mouse Hepatocarcinogenesis

The microRNA 21 (miR-21) is upregulated in almost all known human cancers and is considered a highly potent oncogene and potential therapeutic target for cancer treatment. In the liver, miR-21 was reported to promote hepatic steatosis and inflammation, but whether miR-21 also drives hepatocarcinogenesis remains poorly investigated in vivo. Here we show using both carcinogen (Diethylnitrosamine, DEN) or genetically (PTEN deficiency)-induced mouse models of hepatocellular carcinoma (HCC), total or hepatocyte-specific genetic deletion of this microRNA fosters HCC development-contrasting the expected oncogenic role of miR-21. Gene and protein expression analyses of mouse liver tissues further indicate that total or hepatocyte-specific miR-21 deficiency is associated with an increased expression of oncogenes such as Cdc25a, subtle deregulations of the MAPK, HiPPO, and STAT3 signaling pathways, as well as alterations of the inflammatory/immune anti-tumoral responses in the liver. Together, our data show that miR-21 deficiency promotes a pro-tumoral microenvironment, which over time fosters HCC development via pleiotropic and complex mechanisms. These results question the current dogma of miR-21 being a potent oncomiR in the liver and call for cautiousness when considering miR-21 inhibition for therapeutic purposes in HCC.

Lactobacillus acidophilus LA14 Alleviates Liver Injury

Although the probiotic Lactobacillus acidophilus LA14 is used worldwide, its effect on liver diseases remains unelucidated. Here, 32 rats were divided into four groups, gavaged with L. acidophilus LA14 (3 × 10⁹ CFU) or phosphate-buffered saline for 7 days, and then intraperitoneally injected with d-galactosamine or saline. After 24 h, blood, liver, ileum, and feces samples were collected for liver injury, inflammation, intestinal barrier, gut microbiota, metabolome, and transcriptome analyses. Pretreatment with L. acidophilus LA14 alleviated the d-galactosamine-induced elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bile acids; mitigated the histological injury to the liver and gut; and suppressed the inflammatory cytokines macrophage inflammatory protein 1α (MIP-1α), MIP-3α, and MCP-1. L. acidophilus LA14 also ameliorated the d-galactosamine-induced dysbiosis of the gut microbiota and metabolism, such as the enrichment of Bacteroides sp. strain dnLKV3 and the depletion of Streptococcus, butanoic acid, and N-acetyl-d-glucosamine. The underlying mechanism of L. acidophilus LA14 included prevention of not only the d-galactosamine-induced upregulation of infection- and tumor-related pathways but also the d-galactosamine-induced downregulation of antioxidation-related pathways during this process, as reflected by the liver transcriptome and proteome analyses. Furthermore, the administration of L. acidophilus LA14 to healthy rats did not alter the tested liver indicators but significantly enriched the beneficial Lactobacillus and Bifidobacterium species, promoted metabolism and regulated pathways to improve immunity. The ability of L. acidophilus LA14 to alleviate liver injury was further confirmed with an acetaminophen-induced mouse model. These results might provide a reference for future studies on the application of L. acidophilus LA14 for the prevention of liver injury.

IMPORTANCE The probiotic Lactobacillus acidophilus LA14 is widely used, but its effect on liver diseases has not been elucidated. We explored the protective effect of L. acidophilus LA14 on the liver using rats with d-galactosamine-induced liver injury. Pretreatment with L. acidophilus LA14 alleviated the d-galactosamine-induced elevation of serum ALT, AST, ALP, and bile acids, mitigated the histological injury to the liver and gut, and suppressed the inflammatory cytokines MIP-1α, MIP-3α, and MCP-1. These effects were correlated with the modulations of the gut microbiome, metabolome, and hepatic gene expression induced by L. acidophilus LA14. Moreover, the ability of L. acidophilus LA14 to alleviate liver injury was further confirmed with an acetaminophen-induced mouse model. These results might provide a reference for future studies on the application of L. acidophilus LA14 for the prevention of liver injury.

Role of Small GTPase RhoA in DNA Damage Response

Accumulating evidence has suggested a role of the small GTPase Ras homolog gene family member A (RhoA) in DNA damage response (DDR) in addition to its traditional function of regulating cell morphology. In DDR, 2 key components of DNA repair, ataxia telangiectasia-mutated (ATM) and flap structure-specific endonuclease 1 (FEN1), along with intracellular reactive oxygen species (ROS) have been shown to regulate RhoA activation. In addition, Rho-specific guanine exchange factors (GEFs), neuroepithelial transforming gene 1 (Net1) and epithelial cell transforming sequence 2 (Ect2), have specific functions in DDR, and they also participate in Ras-related C3 botulinum toxin substrate 1 (Rac1)/RhoA interaction, a process which is largely unappreciated yet possibly of significance in DDR. Downstream of RhoA, current evidence has highlighted its role in mediating cell cycle arrest, which is an important step in DNA repair. Unraveling the mechanism by which RhoA modulates DDR may provide more insight into DDR itself and may aid in the future development of cancer therapies.

E3 ubiquitin ligase UBR5 promotes pancreatic cancer growth and aerobic glycolysis by downregulating FBP1 via destabilization of C/EBPα

Pancreatic cancer is one of the most fatal cancers in humans. While it thrives in a state of malnutrition, the mechanism by which pancreatic cancer cells adapt to metabolic stress through metabolic reprogramming remains unclear. Here, we showed that UBR5, an E3 ubiquitin ligase, was significantly upregulated in pancreatic cancer patient samples compared to the levels in adjacent normal tissues. Levels of UBR5 were closely related to a malignant phenotype and shorter survival among pancreatic cancer patients. Multivariate analyses also revealed that UBR5 overexpression was an independent predictor of poor outcomes among patients with pancreatic cancer. Functional assays revealed that UBR5 contributes to the growth of pancreatic cancer cells by inducing aerobic glycolysis. Furthermore, we demonstrated that UBR5 knockdown increased levels of fructose-1,6-bisphosphatase (FBP1), an important negative regulator in the process of aerobic glycolysis in many cancers. We found a significant negative correlation between levels of UBR5 and FBP1, further demonstrating that UBR5-induced aerobic glycolysis is dependent on FBP1 in pancreatic cancer cells. Mechanistically, UBR5 regulates FBP1 expression by modulating C/EBPα, directly binding to C/EBPα, and promoting its ubiquitination and degradation. Together, these results identify a mechanism used by pancreatic cancer cells to survive the nutrient-poor tumour microenvironment and also provide insight regarding the role of UBR5 in pancreatic cancer cell adaptation to metabolic stresses.

LncRNA ARAP1-AS2 promotes high glucose-induced human proximal tubular cell injury via persistent transactivation of the EGFR by interacting with ARAP1

The persistent transactivation of epidermal growth factor receptor (EGFR) causes subsequent activation of the TGF-β/Smad3 pathway, which is closely associated with fibrosis and cell proliferation in diabetic nephropathy (DN), but the exact mechanism of persistent EGFR transactivation in DN remains unclear. ARAP1, a susceptibility gene for type 2 diabetes, can regulate the endocytosis and ubiquitination of membrane receptors, but the effect of ARAP1 and its natural antisense long non-coding RNA (lncRNA), ARAP1-AS2, on the ubiquitination of EGFR in DN is not clear. In this study, we verified that the expression of ARAP1 and ARAP1-AS2 was significantly up-regulated in high glucose-induced human proximal tubular epithelial cells (HK-2 cells). Moreover, we found that overexpression or knockdown of ARAP1-AS2 could regulate fibrosis and HK-2 cell proliferation through EGFR/TGF-β/Smad3 signalling. RNA pulldown assays revealed that ARAP1-AS2 directly interacts with ARAP1. Coimmunoprecipitation, dual-immunofluorescence and ubiquitination assays showed that ARAP1 may maintain persistent EGFR activation by reducing EGFR ubiquitination through competing with Cbl for CIN85 binding. Taken together, our results suggest that the lncRNA ARAP1-AS2 may promote high glucose-induced proximal tubular cell injury via persistent EGFR/TGF-β/Smad3 pathway activation by interacting with ARAP1.

SPAG5 promotes osteosarcoma metastasis via activation of FOXM1/MMP2 axis

Osteosarcoma (OS) is a primary malignancy of bone with a tendency to metastasize early. An understanding of the pathways that regulate OS metastasis is required for the design of novel treatment approaches. Sperm-associated antigen 5 (SPAG5) is upregulated and functions as a potential tumor promoter in diverse human cancers, but has yet to be investigated in the OS. In the present study, results showed that SPAG5 expression is upregulated in OS tissues, and SPAG5 overexpression is obviously associated with the malignant phenotype and poor survival in patients with OS. Multivariate analyses also revealed that SPAG5 overexpression is an independent prognostic factor for poor outcome of patients with OS. The functional assay indicated that SPAG5 silencing significantly inhibits the invasion and migration of OS cells in vitro. Additionally, knockdown of SPAG5 in OS cells suppresses lung metastasis in vivo. Further, we also found that SPAG5 silencing inhibits the epithelial-mesenchymal transition (EMT) process of OS cells. Moreover, our results indicated that SPAG5 promotes OS metastasis by increasing matrix metalloproteinase-2 (MMP2) expression, and demonstrated that MMP2 is crucial for the pro-metastasis role of SPAG5 in OS cells. Mechanistically, we identified that SPAG5 regulates MMP2 expression by modulating FOXM1 (Forkhead box M1) degradation to enhance the protein stability of FOXM1. Collectively, these findings describe the effects of SPAG5-FOXM1-MMP2 axis in the regulation of OS cell migration and metastasis formation. We provide a novel evidence that SPAG5 may serve as a prognostic indicator and potential therapeutic target for patients with osteosarcoma.

ROCK2 promotes osteosarcoma growth and metastasis by modifying PFKFB3 ubiquitination and degradation

Rho-associated coiled-coil-containing protein kinase 2 (ROCK2) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) are widely involved in cell biological activities and play a key role in controlling various cell phenomena. However, the underlying mechanisms connecting ROCK2 and PFKFB3 in osteosarcoma growth and metastasis are poorly understood. In this study, we explored and analysed the role and molecular mechanism of ROCK2 and PFKFB3 in osteosarcoma. We analysed ROCK2 and PFKFB3 protein expression in 51 surgical specimens from osteosarcoma patients and determined the correlation between ROCK2 and PFKFB3. In addition, we used Transwell and wound-healing assays to detect cell invasion and migration and CCK8 and EdU assays to assess cell proliferation. Herein, we confirmed that ROCK2 and PFKFB3 proteins were significantly upregulated in osteosarcoma compared with adjacent normal tissues. Further studies revealed that knockdown of ROCK2 significantly decreased the expression levels of PFKFB3; moreover, growth and metastasis were decreased in shROCK2 osteosarcoma cells. Additionally, upregulation of PFKFB3 rescued the decreased proliferation and metastasis induced by ROCK2 knockdown, whereas knockdown of PFKFB3 decreased ROCK2-enhanced osteosarcoma proliferation and metastasis. These results suggest that PFKFB3 is essential for ROCK2-mediated proliferation and metastasis of osteosarcoma cells. Mechanistically, ROCK2 stabilizes PFKFB3 expression by modifying its ubiquitination and degradation. Taken together, our results link two drivers of proliferation and metastasis in osteosarcoma and identify a novel pathway for PFKFB3 regulation. Thus, we provide new evidence of the biological and clinical significance of PFKFB3 as a potential biomarker for osteosarcoma.

RhoC regulates radioresistance via crosstalk of ROCK2 with the DNA repair machinery in cervical cancer

Background

Radioresistance remains a challenge to the successful treatment of various tumors. Intrinsic factors like alterations in signaling pathways regulate response to radiation. RhoC, which has been shown to modulate several tumor phenotypes has been investigated in this report for its role in radioresistance. In vitro and clinical sample-based studies have been performed to understand its contribution to radiation response in cervical cancer and this is the first report to establish the role of RhoC and its effector ROCK2 in cervical cancer radiation response.

Methods

Biochemical, transcriptomic and immunological approaches including flow cytometry and immunofluorescence were used to understand the role of RhoC and ROCK2. RhoC variants, siRNA and chemical inhibitors were used to alter the function of RhoC and ROCK2. Transcriptomic profiling was performed to understand the gene expression pattern of the cells. Live sorting using an intracellular antigen has been developed to isolate the cells for transcriptomic studies.

Results

Enhanced expression of RhoC conferred radioprotection on the tumor cells while inhibition of RhoC resulted in sensitization of cells to radiation. The RhoC overexpressing cells had a better DNA repair machinery as observed using transcriptomic analysis. Similarly, overexpression of ROCK2, protected tumor cells against radiation while its inhibition increased radiosensitivity in vitro. Further investigations revealed that ROCK2 inhibition abolished the radioresistance phenotype, conferred by RhoC on SiHa cells, confirming that it is a downstream effector of RhoC in this context. Additionally, transcriptional analysis of the live sorted ROCK2 high and ROCK2 low expressing SiHa cells revealed an upregulation of the DNA repair pathway proteins. Consequently, inhibition of ROCK2 resulted in reduced expression of pH2Ax and MRN complex proteins, critical to repair of double strand breaks. Clinical sample-based studies also demonstrated that ROCK2 inhibition sensitizes tumor cells to irradiation.

Conclusions

Our data primarily indicates that RhoC and ROCK2 signaling is important for the radioresistance phenotype in cervical cancer tumor cells and is regulated via association of ROCK2 with the proteins of DNA repair pathway involving pH2Ax, MRE11 and RAD50 proteins, partly offering insights into the mechanism of radioresistance in tumor cells. These findings highlight RhoC-ROCK2 signaling involvement in DNA repair and urge the need for development of these molecules as targets to alleviate the non-responsiveness of cervical cancer tumor cells to irradiation treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1385-7) contains supplementary material, which is available to authorized users.

The interaction of Lin28A/Rho associated coiled-coil containing protein kinase2 accelerates the malignancy of ovarian cancer

Ovarian cancer (OC) is the leading cause of death among women with gynecologic malignant diseases, however, the molecular mechanism of ovarian cancer is not well defined. Previous studies have found that RNA binding protein Lin28A is a key factor of maintain the pluripotency of stem cells, and it is positively correlated with the degree of several cancers (breast, prostate, liver cancer, etc). Our previous study shows that Lin28A is highly expressed in OC tissues and is involved in the regulation of OC cell biological behavior. In this study, we confirmed that high expression of Lin28A promoted the survival, invasion, metastasis, and inhibited the apoptosis of OC cells. Lin28A interacts with Rho associated coiled-coil containing protein kinase2 (ROCK2) but not ROCK1 and upregulates the expression of ROCK2 in OC cells. The binding sites of each other were identified by truncated mutations and Immuno-precipitaion (IP) assay. After knock down of ROCK2 in cells with high expression of Lin28A, the survival, invasion, metastasis was significantly inhibited and early apoptosis was increased in OC cells and OC xenograft in nude mice. Our experimental data also showed that knock down of ROCK2 but not ROCK1 inhibited the invasion by decreasing the expression of N-cadherin, Slug, β-catenin and increasing ZO-1 expression. Simultaneously, knock down of ROCK2 induced cell apoptosis by increasing cleaved Caspase-9,cleaved Caspase-7, and cleaved Caspase-3. Taken together, Lin28A regulated the biological behaviors in OC cells through ROCK2 and the interaction of Lin28A/ROCK2 may be a new target for diagnosis and gene therapy of OC.

MicroRNA‑130a inhibits the proliferation, migration and invasive ability of hepatocellular carcinoma cells by downregulating Rho‑kinase 2

MicroRNA‑130a (miR‑130a) has been reported to be downregulated in hepatocellular carcinoma (HCC). However, the roles and underlying tumor‑suppressive mechanisms of miR‑130a in the pathogenesis of HCC remain unclear. In the current study, reduced expression of miR‑130a was observed in tumor tissues of patients with HCC in addition to in four HCC cell lines, BEL‑7402, MHCC97H, HepG2 and Huh7. Results of methyl thiazolyl tetrazolium (MTT) assays identified decreased growth rates of MHCC97H and HepG2 cells transfected with miR‑130a mimics. The in vitro colony formation assays demonstrated that the number of colonies formed by cells transfected with miR‑130a mimics and cells transfected with miR‑130a inhibitors was lower and higher, respectively, than that formed by the cells transfected with miR‑negative control. In addition, it was identified that overexpression of miR‑130a reduced the migration and invasiveness of MHCC97H and HepG2 cells. Luciferase reporter assays demonstrated that miR‑130a directly targeted the 3'‑untranslated region of Rho‑kinase 2 (ROCK2) mRNA. Northern and western blot analyses indicated that miR‑130a could modulate the mRNA and protein expression of ROCK2. Additionally, small‑interfering RNA‑mediated knockdown of ROCK2 decreased the proliferation, migration and invasiveness of MHCC97H and HepG2 cells. Overall, these observation suggest that miR‑130a is a regulator of ROCK2 and can inhibit proliferation, migration and invasive ability of HCC cells, at least in part, by suppressing the expression of ROCK2. The current study provides further insight into the molecular mechanisms of HCC pathogenesis and suggests a new potential biotarget for HCC treatment.

NEDD4 promotes cell growth and motility in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. In China, the situation is even worse as cancer incidence and mortality continue to increase rapidly. Although tremendous progress has been made toward HCC treatments, the benefits for liver cancer patients are still limited. Therefore, it is necessary to identify and develop novel therapeutic methods. Neuronally expressed developmentally downregulated 4 (NEDD4), an E3 ubiquitin ligase, plays a critical role in the development and progression of various types of human cancers. In our study, NEDD4 acts as an oncoprotein in both QGY7703 and SMMC7721 liver cancer cell lines. We found that depletion of NEDD4 by siRNA transfection led to inhibition of cell growth, invasion and migration, and promotion of apoptosis. In contrast, overexpression of NEDD4 via plasmid transfection resulted in facilitated cell proliferation, invasion and migration, and decreased apoptosis. Importantly, we observed that tumor suppressor LATS1, also a core component of Hippo pathway, was negatively regulated by NEDD4 in liver cancer cells. Our findings suggested that NEDD4 may be involved in the HCC progression via regulating LATS1 associated signaling pathway. Therefore, targeting NEDD4-LATS1 signaling could be a potential therapeutic option for HCC treatment.

NEDD4 promotes cell growth and motility in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. In China, the situation is even worse as cancer incidence and mortality continue to increase rapidly. Although tremendous progress has been made toward HCC treatments, the benefits for liver cancer patients are still limited. Therefore, it is necessary to identify and develop novel therapeutic methods. Neuronally expressed developmentally downregulated 4 (NEDD4), an E3 ubiquitin ligase, plays a critical role in the development and progression of various types of human cancers. In our study, NEDD4 acts as an oncoprotein in both QGY7703 and SMMC7721 liver cancer cell lines. We found that depletion of NEDD4 by siRNA transfection led to inhibition of cell growth, invasion and migration, and promotion of apoptosis. In contrast, overexpression of NEDD4 via plasmid transfection resulted in facilitated cell proliferation, invasion and migration, and decreased apoptosis. Importantly, we observed that tumor suppressor LATS1, also a core component of Hippo pathway, was negatively regulated by NEDD4 in liver cancer cells. Our findings suggested that NEDD4 may be involved in the HCC progression via regulating LATS1 associated signaling pathway. Therefore, targeting NEDD4-LATS1 signaling could be a potential therapeutic option for HCC treatment.

Molecular mechanisms of Ellis‑van Creveld gene variations in ventricular septal defect

The Ellis-van Creveld (EVC) gene is associated with various congenital heart diseases. However, studies on EVC gene variations in ventricular septal defect (VSD) and the underlying molecular mechanisms are sparse. The present study detected 11 single-nucleotide polymorphisms (SNPs) in 65 patients with VSD and 210 control patients from the Chinese Han population. Of the identified SNPs only the c.1727G>A SNP site was positively associated with the development of VSD (P<0.007). A known mutation, c.343C>G, was also identified, which causes a leucine to valine substitution at amino acid 115 of the EVC protein (p.L115V). The results of functional prediction indicated that c.343C>G may be a pathogenic mutation. In addition, in NIH3T3 mouse embryonic fibroblast cells, the EVC c.343C>G mutation significantly decreased cell proliferation and increased apoptosis. Further investigation demonstrated that in NIH3T3 cells, overexpression of EVC c.343C>G mutation reduced the binding between EVC and smoothened, which further downregulated the activity of the hedgehog (Hh) signaling pathway and the expression of downstream cyclin D1 and B-cell lymphoma 2 proteins with SAG. The c.1727G>A SNP of the EVC gene increased VSD susceptibility in patients from the Chinese Han population. The molecular mechanism underlying the development of VSD induced by the EVC c.343C>G mutation may be due to a reduction in the anti-apoptotic and proliferative abilities of cardiomyocytes via downregulation of Hh pathway activity. The results of the present study may provide novel targets for the diagnosis and treatment of patients with VSD.

Downregulation of USP18 inhibits growth and induces apoptosis in hepatitis B virus-related hepatocellular carcinoma cells by suppressing BCL2L1

Ubiquitin-specific peptidase 18 (USP18) is closely related with hepatitis B virus (HBV), which has been involved in tumourigenesis. However, there has been little research into the role of USP18 on the progression of hepatocellular carcinoma (HCC), especially in HBV-related HCC. In present study, we found that USP18 expression was aberrantly elevated in HCC tissues than adjacent non-tumour tissues. Importantly, USP18 expression was higher in HBV-related HCC cell lines (HepG2.2.15 and Hep3B) than HBV-unrelated HCC cell lines. Furthermore, knockdown of USP18 significantly suppressed tumour cell proliferation in vitro and tumour growth in vivo, whereas overexpression of USP18 promoted HCC cells growth. Moreover, our experimental data revealed that USP18 silencing obviously blocked cell cycle at G1 phase and increased cell apoptosis. Finally, BCL2L1, a member of BCL2 family protein, was identified as a downstream gene of USP18. Mechanistically, we found that USP18 directly bind to BCL2L1 and positively regulated its expression in HCC cells. Overall, our results suggested that USP18 has a crucial role in regulating diverse aspects of the pathogenesis of HCC, indicating that it might be a potential therapeutic target.

Rock2 promotes RCC proliferation by decreasing SCARA5 expression through β-catenin/TCF4 signaling

Rho-associated coiled-coil forming protein kinase 2 (Rock2), as a key effector of the small GTPase RhoA, is involved in tumor development. Scavenger receptor class A member 5 (SCARA5) is an important regulator of biological processes in cancer cells. However, the roles and relationship of Rock2 and SCARA5 in renal cell carcinoma (RCC) remain unclear. In this study, we found that Rock2 expression was markedly increased in clinical RCC tissues compared with that in adjacent non-cancerous tissues. High expression of Rock2 was inversely correlated with patient survival in RCC, which indicated that Rock2 may be a prognostic marker in human RCC. In addition, Rock2 knockdown increased SCARA5 expression and suppressed RCC cell proliferation both in vitro and in vivo. Furthermore, we found that the β-catenin/TCF4 pathway contributed to the effect of Rock2 on SCARA5-mediated RCC proliferation. Taken together, these results suggest that this newly identified Rock2-β-catenin/TCF4-SCARA5 axis will provide novel insight into the understanding of the regulatory mechanisms of proliferation in human RCC.

Identification of key genes in hepatocellular carcinoma and validation of the candidate gene, cdc25a, using gene set enrichment analysis, meta-analysis and cross-species comparison

The aim of the present study was to determine key pathways and genes involved in the pathogenesis of hepatocellular carcinoma (HCC) through bioinformatic analyses of HCC microarray data based on cross-species comparison. Microarray data of gene expression in HCC in different species were analyzed using gene set enrichment analysis (GSEA) and meta-analysis. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to determine the mRNA and protein expression levels of cdc25a, one of the identified candidate genes, in human, rat and tree shrew samples. The cell cycle pathway had the largest overlap between the GSEA and meta-analysis. Meta-analyses showed that 25 genes, including cdc25a, in the cell cycle pathway were differentially expressed. Cdc25a mRNA levels in HCC tissues were higher than those in normal liver tissues in humans, rats and tree shrews, and the expression level of cdc25a in HCC tissues was higher than in corresponding paraneoplastic tissues in humans and rats. In human HCC tissues, the cdc25a mRNA level was significantly correlated with clinical stage, portal vein tumor thrombosis and extrahepatic metastasis. Western blotting showed that, cdc25a protein levels were significantly upregulated in HCC tissues in humans, rats and tree shrews. In conclusion, GSEA and meta-analysis can be combined to identify key molecules and pathways involved in HCC. This study demonstrated that the cell cycle pathway and the cdc25a gene may be crucial in the pathogenesis and progression of HCC.

Rock2 stabilizes β-catenin to promote tumor invasion and metastasis in colorectal cancer

Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is an effector for the small GTPase Rho and plays an important role in tumor progression and metastasis. However, the effect of Rock2 in colorectal cancer (CRC) still remains unclear. In this study, we found that Rock2 expression was markedly increased in clinical CRC tissues compared with adjacent non-cancerous tissues. High expression of Rock2 was correlated with tumor metastasis and poor prognosis in CRC. In addition, the knockdown of Rock2 suppressed the invasion and metastasis of CRC cells both in vitro and in vivo. Furthermore, we found that the β-catenin/TCF4 pathway contributed to the effects of Rock2 in CRC cells, and Rock2 stabilized β-catenin by preventing its ubiquitination and degradation. Taken together, this novel pathway for β-catenin control plays a biologically relevant role in CRC metastasis.

Autocrine motility factor receptor promotes the proliferation of human acute monocytic leukemia THP-1 cells

The aberrant activation of autocrine motility factor receptor (AMFR) has been implicated in several types of human cancer. The present study aimed to elucidate the effect of AMFR on the regulation of proliferation in an acute monocytic leukemia cell line, THP‑1. THP‑1 cells were transfected with AMFR‑targeted small interfering (si)RNA and a plasmid encoding a truncated AMFR, AMFR‑C, (pcDNA3.1‑AMFR‑C). The mRNA and protein levels of AMFR and the downstream targets, rho‑associated, coiled‑coil containing protein kinase 2 (ROCK2), cyclin D1, and B‑cell lymphoma (Bcl)‑2, were measured using reverse transcription‑quantitatibe polymerase chain reaction and immunoblot analyses. The effects on cell cycle and apoptosis were investigated using flow cytometry. The present study successfully established the knockdown of AMFR and expression of AMFR‑C in the THP‑1 cells. Downregulation of AMFR induced cell cycle arrest at the G0/G1 phase, and increased apoptosis of the THP‑1 cells (all P<0.05). The AMFR siRNA increased the percentage of early apoptotic cells between 3.88±1.43 and 19.58±4.29% (P<0.05). The expression levels of ROCK2, cyclin D1 and Bcl‑2 were reduced by the downregulation of AMFR and enhanced by overexpression of AMFR‑C. In conclusion, AMFR appears to be crucial for the proliferation of the THP‑1 acute monocytic leukemia cell line. Therefore, AMFR may represent a potential target for the treatment of acute monocytic leukemia.

ROCK2 promotes HCC proliferation by CEBPD inhibition through phospho-GSK3β/β-catenin signaling

Rho-associated kinase 2 (Rock2) is known to promote tumorigenesis in hepatocellular carcinoma (HCC). CCAAT/enhancer-binding protein delta (CEBPD) functions as a tumor suppressor. In this study, we found that the expression of Rock2 and CEBPD are inversely correlated. Knockdown of Rock2 increased CEBPD expression and inhibited the proliferation of HCC cells in vitro and in vivo. Mechanistically, we found that Rock2 regulates CEBPD expression through the p-GSK3β/β-catenin pathway. Taken together, we identified a novel Rock2-p-GSK3β/β-catenin-CEBPD regulatory circuitry, the dysfunction of which may contribute to the tumorigenic characteristic of HCC.

Ubiquitin-like protein FAT10 promotes the invasion and metastasis of hepatocellular carcinoma by modifying β-catenin degradation

The ubiquitin-like protein FAT10 and the homeobox protein HOXB9 each promote metastatic progression in hepatocellular carcinoma (HCC). In this study, we investigated the clinicopathologic significance of FAT10 and HOXB9 in HCC and investigated a mechanistic role for FAT10 in HOXB9-mediated invasiveness and metastasis. Relative to adjacent normal tissues, FAT10 and HOXB9 were markedly overexpressed in HCC, where a positive correlation in their expression and associated malignant characteristics were found. RNAi-mediated silencing of FAT10 decreased HOXB9 expression and inhibited HCC invasion and metastasis in vitro and in vivo. The effects of FAT10 silencing were reversed by HOXB9 overexpression, whereas RNAi-mediated silencing of HOXB9 decreased HCC invasion and metastasis driven by FAT10 overexpression. Mechanistically, FAT10 regulated HOXB9 expression by modulating the β-catenin/TCF4 pathway, directly binding to β-catenin and preventing its ubiquitination and degradation. Together, our results identified a novel HCC regulatory circuit involving FAT10, β-catenin/TCF4, and HOXB9, the dysfunction of which drives invasive and metastatic character in HCC. Cancer Res; 74(18); 5287-300. ©2014 AACR.

MiR-449a functions as a tumor suppressor in endometrial cancer by targeting CDC25A

Accumulating evidence has demonstrated that microRNAs (miRNAs) play critical roles in cancer initiation and development by functioning either as oncogenes or as tumor suppressors. The role of microRNA-449a (miR-449a) in endometrial cancer remains unclear. We examined the levels of miR-449a and miR-449b in benign endometrium, type I and type II endometrial cancer tissues by quantitative real-time polymerase chain reaction. To further investigate the roles of miR-449a in regulating the behavior of endometrial cancer cells, we overexpressed miR-449a in the endometrial cancer cell line HEC-1B, which had low endogenous miR-449a expression. We analyzed the effects of miR-449a overexpression on CDC25 expression, proliferation, invasion and apoptosis of HEC-1B cells. We found that miR-449a and miR-449b levels were markedly reduced in type II endometrial cancer tissues but not in type I endometrial cancer tissues compared with normal endometrium. Overexpression of miR-449a significantly inhibited the proliferation, invasion and clonogenic survival of HEC-1B cells. MiR-449a overexpression also induced apoptosis in HEC-1B cells. In addition, real-time RT-PCR and western blot analysis showed that CDC25A expression was suppressed by miR-449a overexpression. Our results suggest that miR-449a may act as a tumor suppressor by targeting CDC25A in endometrial cancer.

High expression of Cdc25B and low expression of 14-3-3σ is associated with the development and poor prognosis in urothelial carcinoma of bladder

Cdc25 dual-specicity phosphatases are essential regulators at critical stages of cell cycle. Cdc25B is overexpressed in several human tumor types. The activity of Cdc25B is regulated by 14-3-3 dimer. To investigate the roles of Cdc25B and 14-3-3σ in bladder carcinoma, we examined expressions of Cdc25B and 14-3-3σ proteins in bladder carcinoma and cell lines and analyzed their roles in the development and prognosis of urinary bladder carcinoma. Immunohistochmistry was used to detect the expressions of Cdc25B and 14-3-3σ in 105 bladder carcinomas. Moreover, expressions of Cdc25B and 14-3-3σ were analyzed by real-time PCR and Western blot in 40 bladder carcinomas and 20 normal epithelial tissues. Specific siRNA was used to knockdown the expression of Cdc25B or 14-3-3σ. Wild-type plasmid was used to overexpress 14-3-3σ. MTT assay and Flow cytometry were used to examine proliferation and cell cycle of bladder cancer cells. There were higher Cdc25B expression and lower 14-3-3σ expression in carcinomas than in the adjacent normal tissues (P < 0.05), positive and negative correlations being noted with clinical stage and histopathologic grade. Cdc25B expression was positively correlated with recurrence and poor prognosis. Downregulation of Cdc25B resulted in slower growth, more G2/M cells and 14-3-3σ increasing. However, upregulation and downregulation of 14-3-3σ did not affect cell growth and Cdc25B expression. It showed that Cdc25B upregulation and 14-3-3σ downregulation might promote development of bladder cancer and suggested a poor prognosis. Moreover, Cdc25B could play an important role on the bladder cancer cell proliferation and cell cycle progression and regulate expression of 14-3-3σ.

Overexpression of HOXB9 promotes metastasis and indicates poor prognosis in colon cancer

OBJECTIVE

Homeobox B9 (HOXB9) is proposed to be involved in tumor angiogenesis and metastasis. We investigated the role of HOXB9 in the progression of colon cancer.

METHODS

HOXB9 expression was investigated by immunohistochemically and Western blotting in 128 colon cancer patients and the results were analyzed statistically associated with clinicopathological data and survival of the patients. The effect of HOXB9 on cell invasion and metastases abilities were analyzed in vitro and in vivo.

RESULTS

HOXB9 is overexpressed in colon cancer tissues and significantly correlated with metastasis and poor survival of patients (P<0.05, respectively). Additionally, high levels of expression of HOXB9 were observed in metastatic lymph nodes. The down-regulation of HOXB9 expression can inhibit the migration and invasive ability of colon cancer cells, while exogenous expression of HOXB9 in colon cancer cells enhanced cell migration and invasiveness. Moreover, stable knockdown of HOXB9 reduced the liver and lung metastasis of colon cancer in vivo.

CONCLUSIONS

HOXB9 may play an important role in the invasion and metastasis of colon cancer cells and may be a useful biomarker for metastasis and prognostic of colon cancer.