Suihai Wang

RN181 suppresses hepatocellular carcinoma growth by inhibition of the ERK/MAPK pathway†‡

The activation of oncogenes and the inactivation of tumor suppressor genes by mutations or chronic hepatitis virus infections play key roles in the pathogenesis of hepatocellular carcinoma (HCC). Here we report that RN181, a really interesting new gene finger domain‐containing protein, was down‐regulated in highly malignant cell lines and in tumor cells of 139 HCC clinical samples in comparison with adjacent normal liver tissues. The expression of RN181 was strongly associated with the pathological grade of HCC. Alterations of the expression of RN181 by retrovirus‐transduced up‐regulation and short hairpin RNA–mediated down‐regulation demonstrated the function of RN181 as a tumor suppressor because it decreased the proliferation and colony formation of HCC cells in vitro and inhibited tumor growth in vivo by suppressing cell proliferation and enhancing cell apoptosis in xenografted tumors. Proteomic analyses showed that RN181 regulates the expression of many proteins that are important in many cellular processes. Statistical analyses identified 33 proteins with consistent changes (≥2‐fold) in RN181‐transformed cells. Ten of these proteins were up‐regulated by RN181, and 23 were down‐regulated. Representative proteins were validated by western blotting. Interaction network investigations revealed that 20 RN181‐regulated proteins could integrate several key biological processes such as survival, metabolism, and mitogen‐activated protein kinase (MAPK) pathways. Remarkably, 11 of the 33 proteins are associated with MAPK signaling in one or more ways. RN181 suppressed the tyrosine phosphorylation of extracellular signal‐regulated kinase 1/2 (ERK1/2) in cell lines and in tumor cells of xenografts and HCC clinical samples, and removing the suppression increased tumor growth.

MAF1 suppresses AKT‐mTOR signaling and liver cancer through activation of PTEN transcription

The phosphatidylinositol 3‐kinase/phosphatidylinositol 3,4,5‐trisphosphate 3‐phosphatase/protein kinase B/mammalian target of rapamycin (PI3K‐PTEN‐AKT‐mTOR) pathway is a central controller of cell growth and a key driver for human cancer. MAF1 is an mTOR downstream effector and transcriptional repressor of ribosomal and transfer RNA genes. MAF1 expression is markedly reduced in hepatocellular carcinomas, which is correlated with disease progression and poor prognosis. Consistently, MAF1 displays tumor‐suppressor activity toward in vitro and in vivo cancer models. Surprisingly, blocking the synthesis of ribosomal and transfer RNAs is insufficient to account for MAF1s tumor‐suppressor function. Instead, MAF1 down‐regulation paradoxically leads to activation of AKT‐mTOR signaling, which is mediated by decreased PTEN expression. MAF1 binds to the PTEN promoter, enhancing PTEN promoter acetylation and activity. Conclusion: In contrast to its canonical function as a transcriptional repressor, MAF1 can also act as a transcriptional activator for PTEN, which is important for MAF1s tumor‐suppressor function. These results have implications in disease staging, prognostic prediction, and AKT‐mTOR‐targeted therapy in liver cancer. (Hepatology 2016;63:1928‐1942)

PSMA7, A Potential Biomarker of Diseases

Proteasome subunit alpha type 7(PSMA7) is an alpha-type subunit of the 20S proteasome core complex and participates in degrading proteins through ubiquitin-proteasome pathway (UPP) which plays an important role in the regulation of cell proliferation or cell cycle control, transcriptional regulation, immune and stress response, cell differentiation, and apoptosis. Previous studies have demonstrated that PSMA7 can be a target interacting with some important proteins involved in transcription factor regulation, cell cycle transition, viral replication and even tumor initiation and progression, suggesting that PSMA7 could be a potential target for the development of clinical diagnosis and new therapeutic drugs. Here, we review the recent studies on PSMA7 involved in many different cellular processes, ranging from the cell cycle process to antigen processing and tumorigenesis.

Extracellular translationally controlled tumor protein promotes colorectal cancer invasion and metastasis through Cdc42/JNK/ MMP9 signaling

The translationally controlled tumor protein (TCTP) can be secreted independently of the endoplasmic reticulum/Golgi pathway and has extrinsic activities when it is characterized as the histamine releasing factor (HRF). Despite its important role in allergies and inflammation, little is known about how extracellular TCTP affects cancer progression. In this study, we found that TCTP was overexpressed in the interstitial tissue of colorectal cancer (CRC) and its expression correlated with poor survival, high pathological grades and metastatic TNM stage in CRC patients. TCTP expression was greater in metastatic liver tissue than in primary tumors and was increased in highly invasive CRC cells. We demonstrated that the expression of TCTP was regulated by HIF-1α and its release was increased in response to low serum and hypoxic stress. Recombinant human TCTP (rhTCTP) promoted the migration and invasiveness of CRC cells in vitro and contributed to distant liver metastasis in vivo. Furthermore, rhTCTP activated Cdc42, phosphorylated JNK (p-JNK), increasing the translocation of p-JNK from the cytoplasm to the nucleus, as well as the secretion of MMP9. In addition, the expression of TCTP positively correlated with that of Cdc42 and p-JNK in clinical CRC samples. The silencing of Cdc42, JNK and MMP9 significantly inhibited the Matrigel invasion of rhTCTP-enhanced CRC cells. Collectively, these results identify a new role for extracellular TCTP as a promoter of CRC progression and liver metastases via Cdc42/JNK/MMP9 activation.

Tspan5 is an independent favourable prognostic factor and suppresses tumour growth in gastric cancer

Tetraspanins are believed to interact with specific partner proteins forming tetraspanin-enriched microdomains and regulate some aspects of partner protein functions. However, the role of Tspan5 during pathological processes, particularly in cancer biology, remains unknown. Here we report that Tspan5 is significantly downregulated in gastric cancer (GC) and closely associated with clinicopathological features including tumour size and TNM stage. The expression of Tspan5 is inversely correlated with patient overall survival and is an independent prognostic factor in GC. Upregulation of Tspan5 in tumour cells results in inhibition of cell proliferation and colony formation in vitro and suppression of xenograft growth of GC by reducing tumour cell proliferation in vivo. Thus, Tspan5 functions as a tumour suppressor in stomach to control the tumour growth. Mechanistically, Tspan5 inhibits the cell cycle transition from G1-S phase by increasing the expression of p27 and p15 and decreasing the expression of cyclin D1, CDK4, pRB and E2F1. The correlation of Tspan5 expression with the expression of p27, p15, cyclin D1, CDK4, pRB and E2F1 in vivo are also revealed in xenografted tumours. Reconstitution of either cyclin D1 or CDK4 in Tspan5-overexpressing GC cells rescues the inhibitory phenotype produced by Tspan5, suggesting that cyclin D1/CDK4 play a dominant role in mediating the suppression of tumour growth by Tspan5 in GC. Our results suggest that Tspan5 may serve as a prognostic biomarker for predicting outcome of GC patients and provide new insights into the pathogenesis of GC and rational for the development of clinical intervention strategies against GC.

Targeting Procalcitonin with Novel Murine Monoclonal Antibodies

The aim of this study was to produce monoclonal and polyclonal antibodies against procalcitonin (PCT), a valid post-mortem marker of sepsis marker. Monoclonal antibodies (MAbs) were made from hyperimmune Balb/c mice by injecting 50 microg of purified antigen. These mice were immunized four times and given a final boost, and their spleen cells were collected and fused with SP2/0 myeloma cells under the presence of PEG 1450. Hybridomas were screened by indirect enzyme-linked immunosorbent assay (ELISA) using purified protein. Lastly, five MAbs were obtained and designated successfully and were characterized by ELISA and Western immunoblotting. By Western immunoblotting, MAbs were found reactive with the patients serum specifically. The results showed that the monoclonal antibodies could be used for various pathophysiological analyses in further investigations of procalcitonin and in preparing diagnostic kits.

Preparation and characterization of monoclonal antibody against glypican-3.

Glypican-3 (GPC3) has been reported as a novel serum and histochemical marker for hepatocellular carcinoma (HCC) by several groups. As an oncofetal protein, it is expressed abundantly in the fetal liver, inactive in the normal adult liver, and frequently reactivated in HCC. Immunology reagents are urgently needed to proceed with mechanism-related research, clinical validation, and application. In this report, monoclonal antibodies (MAbs) against GPC3 were made from hyperimmune BALB/c mice by injecting 100 μg of purified antigen intraperitoneally. Hybridomas were screened by indirect enzyme-linked immunosorbent assay (ELISA) using purified protein. Finally 13 mouse hybridomas producing MAbs to GPC3 were established. The MAbs obtained were fully characterized using Western blot analysis, immunofluorescence, and immunohistochemistry. The results showed that these antibodies could be used for preliminary application of the next step mechanism-related research and GPC3 expression level analysis.

WAP four-disulfide core domain protein 2 promotes metastasis of human ovarian cancer by regulation of metastasis-associated genes

BackgroundWAP four-disulfide core domain protein 2 (WFDC2) shows a tumor-restricted upregulated pattern of expression in ovarian cancer.MethodsIn this study, we evaluated the role of WFCD2 in tumor mobility, invasion and metastasis of ovarian cancer in clinical tissue and in ovarian cancer cells, both in vitro and in vivo.ResultsOur results revealed WFCD2 was overexpressed in ovarian tissues, and the expression level of WFCD2 was associated with metastasis and lymph node metastasis. Higher expression of WFCD2 was also observed in aggressive HO8910-PM cells than in HO8910 cells, and WFCD2 knockdown halted cell migration, invasion, tumorigenicity and metastasis in ovarian cancer cells, both in vitro and in vivo. Knockdown of WFDC2 induced the down-regulation of ICAM-1, CD44, and MMP2.ConclusionIn summary, our work demonstrates that WFCD2 promotes metastasis in ovarian cancer. These findings suggest that WFCD2 plays a critical role in promoting metastasis and may constitute a potential therapeutic target of ovarian cancer.