Jeng-Wei Lu

H3K9 Histone Methyltransferase, KMT1E/SETDB1, Cooperates with the SMAD2/3 Pathway to Suppress Lung Cancer Metastasis

Aberrant histone methylation is a frequent event during tumor development and progression. KMT1E (also known as SETDB1) is a histone H3K9 methyltransferase that contributes to epigenetic silencing of both oncogenes and tumor suppressor genes in cancer cells. In this report, we demonstrate that KMT1E acts as a metastasis suppressor that is strongly downregulated in highly metastatic lung cancer cells. Restoring KMT1E expression in this setting suppressed filopodia formation, migration, and invasive behavior. Conversely, loss of KMT1E in lung cancer cells with limited metastatic potential promoted migration in vitro and restored metastatic prowess in vivo. Mechanistic investigations indicated that KMT1E cooperates with the TGFβ-regulated complex SMAD2/3 to repress metastasis through ANXA2. Together, our findings defined an essential role for the KMT1E/SMAD2/3 repressor complex in TGFβ-mediated lung cancer metastasis.

Zebrafish as a disease model for studying human hepatocellular carcinoma.

Liver cancer is one of the worlds most common cancers and the second leading cause of cancer deaths. Hepatocellular carcinoma (HCC), a primary hepatic cancer, accounts for 90%-95% of liver cancer cases. The pathogenesis of HCC consists of a stepwise process of liver damage that extends over decades, due to hepatitis, fatty liver, fibrosis, and cirrhosis before developing fully into HCC. Multiple risk factors are highly correlated with HCC, including infection with the hepatitis B or C viruses, alcohol abuse, aflatoxin exposure, and metabolic diseases. Over the last decade, genetic alterations, which include the regulation of multiple oncogenes or tumor suppressor genes and the activation of tumorigenesis-related pathways, have also been identified as important factors in HCC. Recently, zebrafish have become an important living vertebrate model organism, especially for translational medical research. In studies focusing on the biology of cancer, carcinogen induced tumors in zebrafish were found to have many similarities to human tumors. Several zebrafish models have therefore been developed to provide insight into the pathogenesis of liver cancer and the related drug discovery and toxicology, and to enable the evaluation of novel small-molecule inhibitors. This review will focus on illustrative examples involving the application of zebrafish models to the study of human liver disease and HCC, through transgenesis, genome editing technology, xenografts, drug discovery, and drug-induced toxic liver injury.

Suramin Inhibits Chikungunya Virus Entry and Transmission.

The mosquito-borne Chikungunya virus (CHIKV) is a profound global threat due to its high rate of contagion and the lack of vaccine or effective treatment. Suramin is a symmetric polyanionic naphthylurea that is widely used in the clinical treatment of parasite infections. Numerous studies have reported the broad antiviral activities of suramin; however, inhibition effects against CHIKV have not yet been demonstrated. The aim of this study was thus to investigate the antiviral effect of suramin on CHIKV infection and to elucidate the molecular mechanism underlying inhibition using plaque reduction assay, RT-qPCR, western blot analysis, and plaque assay. Microneutralization assay was used to determine the EC50 of suramin in the CHIKV-S27 strain as well as in three other clinical strains (0611aTw, 0810bTw and 0706aTw). Time-of-addition was used to reveal the anti-CHIKV mechanism of suramin. We also evaluated anti-CHIKV activity with regard to viral entry, virus release, and cell-to-cell transmission. Cytopathic effect, viral RNA, viral protein, and the virus yield of CHIKV infection were shown to diminish in the presence of suramin in a dose-dependent manner. Suramin was also shown the inhibitory activities of the three clinical isolates. Suramin inhibited the early progression of CHIKV infection, due perhaps to interference with virus fusion and binding, which subsequently prevented viral entry. Results of a molecular docking simulation indicate that suramin may embed within the cavity of the E1/E2 heterodimer to interfere with their function. Suramin was also shown to reduce viral release and cell-to-cell transmission of CHIKV. In conclusion, Suramin shows considerable potential as a novel anti-CHIKV agent targeting viral entry, extracellular transmission, and cell-to-cell transmission.

Zebrafish as a Model for the Study of Human Myeloid Malignancies

Myeloid malignancies are heterogeneous disorders characterized by uncontrolled proliferation or/and blockage of differentiation of myeloid progenitor cells. Although a substantial number of gene alterations have been identified, the mechanism by which these abnormalities interact has yet to be elucidated. Over the past decades, zebrafish have become an important model organism, especially in biomedical research. Several zebrafish models have been developed to recapitulate the characteristics of specific myeloid malignancies that provide novel insight into the pathogenesis of these diseases and allow the evaluation of novel small molecule drugs. This report will focus on illustrative examples of applications of zebrafish models, including transgenesis, zebrafish xenograft models, and cell transplantation approaches, to the study of human myeloid malignancies.

Overexpression of FLT3-ITD driven by spi-1 results in expanded myelopoiesis with leukemic phenotype in zebrafish.

Overexpression of FLT3 -ITD driven by spi - 1 results in expanded myelopoiesis with leukemic phenotype in zebrafish

Tissue microarray-based study of hepatocellular carcinoma validating SPIB as potential clinical prognostic marker

Currently, the prognostic significance of SPIB protein overexpression in human hepatocellular carcinoma (HCC) is unclear. The aim of the present study was to investigate the level of SPIB expression in human HCC in order to determine possible correlations between SPIB expression and clinicopathological findings. The expression of SPIB proteins was detected using immunohistochemical staining in commercial multiple-tissue microarrays as a means of examining expression profiles in patients. Using online biomarker validation tool SurvExpress, we focused on the correlation between SPIB overexpression and survival as well as relapse-free survival (RFS). Results show that SPIB protein expression levels were significantly higher in colon, liver, and stomach tumors than in non-tumor tissues (p<0.05). SPIB overexpression in patients with HCC was also significantly higher than that of the normal samples (p<0.001). Among patients with liver disease, SPIB protein expression levels differ significantly according to the stage of liver disease, specifically between stages I, II, and III of HCC (p<0.05). SPIB expression was also shown to be significantly correlated with age (p=0.046) and histological grade (p=0.027). Furthermore, the SurvExpress analysis suggested that high SPIB and KI-67 mRNA expression were significantly associated with the poor survival of patients with HCC (p<0.05). Our results indicate that cross-talk in the expression of SPIB and KI-67 may be associated with poor prognosis and may potentially serve as a clinical prognostic indicator of HCC. This is the first time that such an association has been reported.

JMJD2B as a potential diagnostic immunohistochemical marker for hepatocellular carcinoma: A tissue microarray-based study

The purpose of this study was to examine JMJD2B expression in human hepatocellular carcinoma (HCC) and elucidate relationships between various expression patterns and clinicopathological parameters of HCC patients. Immunohistochemical techniques were performed to detect JMJD2B expression in a tissue microarray from patients with breast, cerebrum, colon, esophagus, kidney, liver, lung, prostate, stomach, and uterus cancers. We performed immunohistochemical staining of a multiple tissue array to examine the expression profile of JMJD2B. Our results demonstrate that JMJD2B protein levels were upregulated in malignant human tumors, including breast, colon, liver, and lung. Immunohistochemistry staining examination of liver tumor tissue microarray revealed that the expression of JMJD2B is significant according to the histological grade and TNM stage of liver tumor. Moreover, JMJD2B was also correlated with Ki-67 expression in HCC samples. These results reveal that JMJD2B is dramatically upregulated in HCC, making it a potential diagnostic marker for the further development of HCC treatment therapies.

Cabozantinib is selectively cytotoxic in acute myeloid leukemia cells with FLT3-internal tandem duplication (FLT3-ITD).

Cabozantinib is an oral multikinase inhibitor that exhibits anti-tumor activity in several cancers. We found that cabozantinib was significantly cytotoxic to MV4-11 and Molm-13 cells that harbored FLT3-ITD, resulting in IC50 values of 2.4 nM and 2.0 nM, respectively. However, K562, OCI-AML3 and THP-1 (leukemia cell lines lacking FLT3-ITD) were resistant to cabozantinib, showing IC50 values in the micromolar range. Cabozantinib arrested MV4-11 cell growth at the G0/G1 phase within 24 h, which was associated with decreased phosphorylation of FLT3, STAT5, AKT and ERK. Additionally, cabozantinib induced MV4-11 cell apoptosis in a dose-dependent manner (as indicated by annexin V staining and high levels of cleaved caspase 3 and PARP-1), down-regulated the anti-apoptotic protein survivin and up-regulated the pro-apoptotic protein Bak. Thus, cabozantinib is selectively cytotoxic to leukemia cells with FLT3-ITD, causing cell-cycle arrest and apoptosis. In mouse xenograft model, cabozantinib significantly inhibited MV4-11 and Molm-13 tumor growth at a dosage of 10 mg/kg and showed longer survival rate. Clinical trials evaluating the efficacy of cabozantinib in acute myeloid leukemia (AML) with FLT3-ITD are warranted.

MK-2206 induces apoptosis of AML cells and enhances the cytotoxicity of cytarabine

Genetic alterations in the PI3K/AKT cascade have been linked to various human cancers including acute myeloid leukemia (AML) and have emerged to be promising targets for treatment. In this study, we explored the molecular mechanism and clinical implication of a specific allosteric AKT inhibitor, MK-2206, in the treatment of AML. Four leukemia cell lines, MV-4-11, MOLM-13, OCI/AML3, and U937, were used. Apoptosis and cell cycle distribution were determined by flow cytometry analysis. Expression of anti-apoptotic protein family and glycogen synthase kinase 3β (GSK3β) signaling was determined by western blotting. Drug combination effects of MK-2206 with cytarabine were evaluated by cell proliferation assay, and the combination index values were calculated by CompuSyn software. MK-2206 had no effect on normal peripheral blood mononuclear cells, but induced G1-phase arrest and apoptosis in leukemia cells. Among anti-apoptotic Bcl-2 family members, only myeloid cell leukemia-1 (Mcl-1) was significantly suppressed. Mcl-1 suppression by MK-2206 was closely associated with decreased GSK3β phosphorylation at Ser9, an event leads to GSK3β activation. Furthermore, the effect of MK-2206 on Mcl-1 downregulation was abolished by GSK3β inhibitor, lithium chloride and proteasome inhibitor, MG-132, suggesting that MK-2206 acted through a GSK3β-mediated, proteasome-dependent protein degradation. In addition, co-administration of MK-2206 with cytarabine could enhance the cytotoxic efficacy of cytarabine in leukemia cell lines. In conclusion, we have demonstrated that MK-2206 is an active agent in AML and its efficacy as in combination with cytarabine is implicated.

Micafungin is a novel anti-viral agent of chikungunya virus through multiple mechanisms

&NA; The chikungunya virus (CHIKV) is a mosquito‐borne virus that belongs to the genus Alphavirus, family Togaviridae. It is the cause of chikungunya fever in humans, which presents a serious global threat due to its high rate of contagion. The clinical symptoms of CHIKV include fever and persistent, severe arthritis. Micafungin has broad‐spectrum fungicidal activity against Candida spp. is a promising echinocandin that was recently approved by the U.S. Food and Drug Administration (FDA) and has demonstrated activity against Candida and Aspergillus. Recent studies have demonstrated the antiviral activity of micafungin; however, the inhibitory effects against CHIKV have yet to be investigated. Our objectives in this study were to explore the antiviral effects of micafungin on CHIKV infection and to elucidate the potential molecular mechanisms of inhibition. We determined that micafungin has the ability to counter CHIKV‐induced cytopathic effects. We further discovered that micafungin limits virus replication, release, cell‐to‐cell transmission, and also slightly affected virus stability during high doses treatment. The efficacy of micafungin was further confirmed against two clinical isolates of CHIKV and two alphaviruses: Sindbis virus (SINV) and Semliki Forest virus (SFV). Our findings suggest that micafungin has considerable potential as a novel inhibitor against the viral replication, and intracellular and extracellular transmission of CHIKV, and has a little effect on virus stability. Our findings also suggest that micafungin could have curative effects on other alphavirus infections. HighlightsMicafungin was identified as a new anti‐CHIKV agent.The anti‐CHIKV effect of micafungin is also proved by CHIKV two clinical isolates.Micafungin could also possess the ability to against other alphaviruses.