Ubiquitin ligase NEDD4 promotes the proliferation of hepatocellular carcinoma cells through targeting PCDH17 protein for ubiquitination and degradation.

Neural precursor cell expressed developmentally downregulated 4 (NEDD4), an E3 ubiquitin ligase, is commonly upregulated in human hepatocellular carcinoma (HCC) and functions as an oncogenic factor in the progression of HCC, but the molecular mechanism needs be further explored. In this study, we found that NEDD4 could facilitate the proliferation of HCC cells, which was associated with regulating the ERK signaling. Further investigation showed that protocadherin 17 (PCDH17) was a potential substrate of NEDD4, and restoration of PCDH17 could block the facilitation of ERK signaling and HCC cells proliferation induced by NEDD4 overexpression. Whereafter, we confirmed that NEDD4 interacted with PCDH17 and promoted the Lys33-linked polyubiquitination and degradation of it via the proteasome pathway. Finally, NEDD4 protein level was found to be inversely correlated with that of PCDH17 in human HCC tissues. In conclusion, these results suggest that NEDD4 acts as an E3 ubiquitin ligase for PCDH17 ubiquitination and degradation thereby promoting the proliferation of HCC cells through regulating the ERK signaling, which may provide novel evidence for NEDD4 to be a promising therapeutic target for HCC.

Cathepsin K promotes the proliferation of hepatocellular carcinoma cells through induction of SIAH1 ubiquitination and degradation.

Seven in absentia homolog 1 (SIAH1) was reported to be downregulated in hepatocellular carcinoma (HCC) and played an important role in HCC progression; however, the underlying reason remains unknown. Here, we found that Cathepsin K (CTSK), a protein potentially interacting with SIAH1, inhibits SIAH1 protein level. CTSK was highly expressed in HCC tissues. CTSK inhibition or downregulation suppressed HCC cell proliferation, whereas CTSK overexpression had the opposite effect; it promotes HCC cell proliferation by regulating the SIAH1/protein kinase B (AKT) pathway, wherein promotes SIAH1 ubiquitination. Neural precursor cells expressing developmentally downregulated 4 (NEDD4) was found to be a potential upstream ubiquitin ligase of SIAH1. Further, CTSK could mediate SIAH1 ubiquitination and degradation by increasing SIAH1 autoubiquitination and recruiting NEDD4 to ubiquitinate SIAH1. Finally, the roles of CTSK were confirmed in a xenograft mouse model. In conclusion, oncogenic CTSK was upregulated in human HCC tissues and accelerated HCC cell proliferation by downregulating SIAH1.

SIAH1/CTR9 axis promotes the epithelial-mesenchymal transition of hepatocellular carcinoma.

SIAH1 has been reported to participate in several human cancers, including hepatocellular carcinoma (HCC). However, the effect of SIAH1 on the epithelial-mesenchymal transition (EMT) has not been reported in HCC cells. Here, we discovered the inhibitory effect of SIAH1 on HCC cell migration and invasion, which was related with regulating EMT. Molecularly, a yeast two-hybrid experiment indicated that Cln Three Requiring 9 (CTR9) was a potential interacting protein of SIAH1, which was further verified by co-immunoprecipitation assays. Furthermore, SIAH1 inhibited the EMT of HCC cells through negatively regulating CTR9. Importantly, CTR9 was ubiquitinated and degraded by SIAH1 via the proteasome pathway in HCC cells. Additionally, it was showed that SIAH1 mainly mediated the K48-linked polyubiquitination on CTR9. Finally, the protein level of CTR9 was found to be inversely correlated with SIAH1 in human HCC tissues. Summed up all together, these findings reveal that SIAH1/CTR9 axis promotes the EMT of HCC cells and is a promising therapeutic target for HCC therapy.

Transcriptional regulator CTR9 promotes hepatocellular carcinoma progression and metastasis via increasing PEG10 transcriptional activity.

Cln Three Requiring 9 (CTR9), a scaffold protein of the polymerase-associated factor-1 (PAF1) complex (PAF1c), is primarily localized in the nucleus of cells. Recent studies show that CTR9 plays essential roles in the development of various human cancers and their occurrence; however, its regulatory roles and precise mechanisms in hepatocellular carcinoma (HCC) remain unclear. In this study, we investigated the roles of CTR9 using in vitro assays and a xenograft mouse model. We found that CTR9 protein is upregulated in tumor tissues from HCC patients. Knockdown of CTR9 substantially reduced HCC cell proliferation, invasion, and migration, whereas its overexpression promoted these activities. In addition, in vitro results revealed that CTR9 silencing dramatically increased cell cycle regulators, p21 and p27, but markedly decreased matrix metalloproteinases, MMP2 and MMP9, with these outcomes reversed upon CTR9 overexpression. Furthermore, the underlying molecular mechanism suggests that CTR9 promoted the oncogene paternally expressed gene 10 (PEG10) transcription via its promoter region. Finally, the oncogenic roles of CTR9 were confirmed in a xenograft mouse model. This study confirms that CTR9, an oncoprotein that promotes HCC cell proliferation, invasion, and migration, increases tumor growth in a xenograft mouse model. CTR9 could be a novel therapeutic target. Further investigation is warranted to verify CTR9 potential in novel therapies for HCC.

CircIL4R activates the PI3K/AKT signaling pathway via the miR-761/TRIM29/PHLPP1 axis and promotes proliferation and metastasis in colorectal cancer.

BACKGROUND: Accumulating studies have revealed that aberrant expression of circular RNAs (circRNAs) is widely involved in the tumorigenesis and progression of malignant cancers, including colorectal cancer (CRC). Nevertheless, the clinical significance, levels, features, biological function, and molecular mechanisms of novel circRNAs in CRC remain largely unexplored. METHODS: CRC-related circRNAs were identified through bioinformatics analysis and verified in clinical specimens by qRT-PCR and in situ hybridization (ISH). Then, in vitro and in vivo experiments were performed to determine the clinical significance of, functional roles of, and clinical characteristics associated with circIL4R in CRC specimens and cells. Mechanistically, RNA pull-down, fluorescence in situ hybridization (FISH), luciferase reporter, and ubiquitination assays were performed to confirm the underlying mechanism of circIL4R. RESULTS: CircIL4R was upregulated in CRC cell lines and in sera and tissues from CRC patients and was positively correlated with advanced clinicopathological features and poor prognosis. Functional experiments demonstrated that circIL4R promotes CRC cell proliferation, migration, and invasion via the PI3K/AKT signaling pathway. Mechanistically, circIL4R was regulated by TFAP2C and competitively interacted with miR-761 to enhance the expression of TRIM29, thereby targeting PHLPP1 for ubiquitin-mediated degradation to activate the PI3K/AKT signaling pathway and consequently facilitate CRC progression. CONCLUSIONS: Our findings demonstrate that upregulation of circIL4R plays an oncogenic role in CRC progression and may serve as a promising diagnostic and prognostic biomarker for CRC detection and as a potential therapeutic target for CRC treatment.

Quiescin Sulfhydryl Oxidase 2 Overexpression Predicts Poor Prognosis and Tumor Progression in Patients With Colorectal Cancer: A Study Based on Data Mining and Clinical Verification.

Background: As a member of the atypical thiol oxidase family, quiescin sulfhydryl oxidase 2 (QSOX2) has been reported to play an important role in several biological processes, but the expression and function of QSOX2 in colorectal cancer (CRC) remains elusive. Methods: The difference of QSOX2 expression, and its relationship with clinicopathological features and prognosis in CRC, was analyzed by bioinformatic analysis and validated by clinical CRC specimen cohort. The functional characterization of QSOX2 was detected via in vitro and vivo experiments in CRC cell lines, while the potential signaling pathways were predicted by Gene Set Enrichment Analysis (GSEA). Results: Our data based on bioinformatical analysis and clinical validation demonstrated that the expression of QSOX2 in CRC tissues was significantly upregulated. Additionally, the chi-square test, logistic regression analysis, and Fisher's exact test showed that QSOX2 overexpression was significantly correlated with advanced clinicopathological parameters, such as pathological stage and lymph node metastasis. The Kaplan-Meier curves and univariate Cox regression model showed that QSOX2 overexpression predicts poor overall survival (OS) and disease-free survival (DFS) in CRC patients. More importantly, multivariate Cox regression model showed that QSOX2 overexpression could serve as an independent factor for CRC patients. In vitro and vivo data showed that the proliferation and metastasis ability of CRC cells were suppressed on condition of QSOX2 inhibition. In addition, GSEA showed that the QSOX2 high expression phenotype has enriched multiple potential cancer-related signaling pathways. Conclusion: QSOX2 overexpression is strongly associated with malignant progression and poor oncological outcomes in CRC. QSOX2 might act as a novel biomarker for prognosis prediction and a new target for biotherapy in CRC.

The circular RNA circSPARC enhances the migration and proliferation of colorectal cancer by regulating the JAK/STAT pathway.

BACKGROUND: Noncoding RNAs such as circular RNAs (circRNAs) are abundant in the human body and influence the occurrence and development of various diseases. However, the biological functions of circRNAs in colorectal cancer (CRC) are largely unknown. METHODS: RT-qPCR was used to detect the expression of circRNAs and mRNA in CRC cells and tissues. Fluorescence in situ hybridization (FISH) was used to analyze the location of circSPARC. Function-based experiments were performed using circSPARC knockdown and overexpression cell lines in vitro and in vivo, including CCK8, colony formation, transwell and metastasis models. Mechanistically, luciferase reporter assay, western blots, RNA immunoprecipitation (RIP), Chromatin isolation by RNA purification (ChIRP) and immunohistochemical stainings were performed. RESULTS: CircSPARC was upregulated in both the tissues and plasma of CRC patients. High expression of circSPARC was associated with advanced TNM stage, lymph node metastases, and poor survival. Silencing circSPARC inhibited CRC cell migration and proliferation in vitro and vivo. Mechanistically, circSPARC sponged miR-485-3p to upregulate JAK2 expression and ultimately contribute to the accumulation of phosphorylated (p)-STAT3. Besides, circSPARC recruited FUS, which facilitated the nuclear translocation of p-STAT3. CONCLUSIONS: These findings suggest that circSPARC might serve as a potential diagnostic and prognostic biomarker and a therapeutic target for CRC treatment by regulating JAK2/STAT3 pathway.

Clinical findings in a group of COVID-19 patients: a single-center retrospective study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) is spreading rapidly across countries and has infected tens of millions of people all over the world. So far, the pandemic is ongoing globally, and the situation is still worsening. METHODS: In this retrospective, single-center cohort analysis, we included 25 adult inpatients with laboratory confirmed COVID-19 disease from the affiliated hospital of Xuzhou Medical University (Xuzhou, China). Epidemiological characterizations, clinical findings, and medical treatments were all reported. In addition, laboratory markers were investigated in terms of course of treatment. RESULTS: Epidemiological features and clinical findings were present for all 25 patients. Laboratory markers were identified due to temporal changes. After medical treatment, all patients were discharged home and recovering from the infection. CONCLUSIONS: This study provides a comprehensive overview of patients with COVID-19 disease in a single hospital. Some of the laboratory markers were statistically different during the course of the disease, which might serve as indicators in identifying patients with COVID-19 disease at an early stage of the infection.

Long non­coding RNA ST8SIA6­AS1 promotes the migration and invasion of hypoxia­treated hepatocellular carcinoma cells through the miR­338/MEPCE axis.

Hepatocellular carcinoma (HCC) is one of the most prevalent types of cancer worldwide. Long non­coding RNAs (lncRNAs) have been reported to frequently participate in the carcinogenesis and development of various types of cancer, including HCC. However, the molecular mechanisms of lncRNA ST8SIA6­AS1 in HCC remain poorly understood. The present study performed bioinformatics analysis, in addition to using reverse transcription­quantitative PCR (RT­qPCR), nuclear­cytoplasmic fractionation, RNA immunoprecipitation, and Transwell, wound healing, and dual­luciferase reporter assays, to determine the biological role and regulatory mechanisms of ST8SIA6­AS1 in HCC. The results revealed that the expression levels of ST8SIA6­AS1 were upregulated in HCC tissues and cell lines, which were associated with a poor prognosis. Moreover, the genetic knockdown of ST8SIA6­AS1 inhibited the hypoxia­induced HCC cell migration and invasion. Additionally, microRNA (miR)­338, which exhibited downregulated expression levels in HCC tissues and cell lines, was discovered to bind with ST8SIA6­AS1. The inhibition of miR­338 partially reversed the inhibitory effects of ST8SIA6­AS1­knockdown on the migration and invasion of HCC cells under hypoxia. Subsequently, methylphosphate capping enzyme (MEPCE) was identified to be targeted and negatively regulated by miR­338. Notably, the overexpression of MEPCE recovered the inhibitory influence over the migratory and invasive abilities of hypoxia­treated HCC cells promoted by ST8SIA6­AS1 inhibition. In conclusion, the findings of the present study suggest that lncRNA ST8SIA6­AS1 may promote the migration and invasion of hypoxia­induced HCC cells via the miR­338/MEPCE axis, indicating a potential diagnostic or therapeutic marker for HCC treatment.

ANP32A promotes the proliferation, migration and invasion of hepatocellular carcinoma by modulating the HMGA1/STAT3 pathway.

Acidic leucine-rich nuclear phosphoprotein-32A (ANP32A) has been reported to play an essential role in the development and progression of various human cancers. However, its expression pattern and possible mechanism in human hepatocellular carcinoma (HCC) remain to be elucidated. In this study, we used western blot and immunohistochemical staining to detect protein expression. The effects of ANP32A on the proliferation, migration and invasion of HCC cells were examined using 5-ethynyl-20-deoxyuridine (EdU), colony formation, CCK-8, and transwell assays. RT-qPCR was performed to detect mRNA expression. The interaction between ANP32A and the high mobility group A1 (HMGA1) mRNA was assessed using RNA immunoprecipitation (RIP). The tumorigenicity of ANP32A was assessed by establishing a xenograft tumor model in Balb/c nude mice. We found that the ANP32A protein was expressed at high levels in patients with HCC, which was associated with a poor prognosis. Functional experiments revealed that the silencing of ANP32A inhibited the proliferation, migration, and invasion of HCC cells, whereas overexpression of ANP32A promoted these processes. Further investigations indicated that ANP32A bound the HMGA1 mRNA and maintained its stability to promote the expression of HMGA1, thereby increasing the expression and activation of STAT3. Finally, a xenograft tumor model of Balb/c nude mice confirmed the tumorigenicity of ANP32A. This study found that ANP32A is up-regulated in patients with HCC and may accelerate the proliferation, migration and invasion of HCC cells by modulating the HMGA1/STAT3 pathway.

Circ-SPECC1 modulates TGFß2 and autophagy under oxidative stress by sponging miR-33a to promote hepatocellular carcinoma tumorigenesis.

Circular RNAs (circRNAs) play vital roles in the pathogenesis and development of multiple cancers, including hepatocellular carcinoma (HCC). Nevertheless, the regulatory mechanisms of circ-SPECC1 in HCC remain poorly understood. In our study, we found that circ-SPECC1 was apparently downregulated in H2 O2 -treated HCC cells. Additionally, knockdown of circ-SPECC1 inhibited cell proliferation and promoted cell apoptosis of HCC cells under H2 O2 treatment. Moreover, circ-SPECC1 inhibited miR-33a expression by direct interaction, and miR-33a inhibitor partially reversed the effect of circ-SPECC1 knockdown on proliferation and apoptosis of H2 O2 -treated HCC cells. Furthermore, TGFß2 was demonstrated to be a target gene of miR-33a and TGFß2 overexpression rescued the phenotypes of HCC cells attenuated by miR-33a mimics. Meanwhile, autophagy inhibition by 3-methyladenine (3-MA) abrogated the effect of miR-33a mimics on proliferation and apoptosis of H2 O2 -treated HCC cells. Finally, knockdown of circ-SPECC1 hindered tumor growth in vivo. In conclusion, our study demonstrated that circ-SPECC1 regulated TGFß2 and autophagy to promote HCC tumorigenesis under oxidative stress via miR-33a. These findings might provide potential treatment strategies for patients with HCC.

TSG101 promotes the proliferation, migration and invasion of hepatocellular carcinoma cells by regulating the PEG10.

The tumour susceptibility gene 101 (TSG101) is reported to play important roles in the development and progression of several human cancers. However, its potential roles and underlined mechanisms in human hepatocellular carcinoma (HCC) are still needed to be further clarified. In the present study, we reported that knock down of TSG101 suppressed the proliferation, migration and invasion of HCC cells, while overexpression of TSG101 facilitated them. Molecularly, the results revealed that knock down of TSG101 significantly decreased the cell cycle related regulatory factor p53 and p21. In another point, knock down of TSG101 also obviously decreased the level of metallopeptidase inhibitor TIMP1 (Tissue inhibitors of metalloproteinases 1), which results in inhibition of MMP2, MMP7 and MMP9. In contrast, overexpression of TSG101 had opposite effects. The iTRAQ proteomics analysis identified that oncogenic protein PEG10 (Paternally expressed gene 10) might be a potential downstream target of TSG101. Further investigation showed that TSG101 interacted with PEG10 and protected it from proteasomal degradation thereby regulating the expression of p53, p21 and MMPs. Finally, we found that both TSG101 and PEG10 proteins are up-regulated and presented a direct correlation in HCC patients. In conclusion, these results suggest that TSG101 is up-regulated in human HCC patients, which may accelerate the proliferation, migration and invasion of HCC cells through regulating PEG10.

Regulation of cell-cell fusion by nanotopography.

Cell-cell fusion is fundamental to a multitude of biological processes ranging from cell differentiation and embryogenesis to cancer metastasis and biomaterial-tissue interactions. Fusogenic cells are exposed to biochemical and biophysical factors, which could potentially alter cell behavior. While biochemical inducers of fusion such as cytokines and kinases have been identified, little is known about the biophysical regulation of cell-cell fusion. Here, we designed experiments to examine cell-cell fusion using bulk metallic glass (BMG) nanorod arrays with varying biophysical cues, i.e. nanotopography and stiffness. Through independent variation of stiffness and topography, we found that nanotopography constitutes the primary biophysical cue that can override biochemical signals to attenuate fusion. Specifically, nanotopography restricts cytoskeletal remodeling-associated signaling, which leads to reduced fusion. This finding expands our fundamental understanding of the nanoscale biophysical regulation of cell fusion and can be exploited in biomaterials design to induce desirable biomaterial-tissue interactions.

Hepatitis B virus X protein reduces the stability of Nrdp1 to up-regulate ErbB3 in hepatocellular carcinoma cells.

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) is the most widespread type of liver cancer. However, the underlying mechanism of HCC tumorigenesis is very intricate and HBV-encoded X protein (HBx) has been reported to play a key role in this process. It has been reported that HBx up-regulates the transcription of ErbB3. However, it remains unclear whether HBx can regulate ErbB3 expression at post-translational modification level. In this study, we showed that HBx interacts with ubiquitin ligase Nrdp1 (neuregulin receptor degradation protein 1) and decreases its stability, which results in the up-regulation of ErbB3 and promotion of HCC cells. Moreover, the expression of ErbB3 was almost undetectable in normal liver tissues but was relative abundant in HCC tissues, and the level of ErbB3 and Nrdp1 significantly showed a negative correlation in HCC tissues. Taken together, these findings suggest that HBx promotes the progression of HCC by decreasing the stability of Nrdp1, which results in up-regulation of ErbB3, suggesting that ErbB3 may be a target for HCC therapy.