Junfen Ma

MAPK/ERK1/2 signaling mediates endothelial-like differentiation of immature DCs in the microenvironment of esophageal squamous cell carcinoma

Endothelial-like differentiation of dendritic cells (DCs) is a new phenomenon, and the mechanism is still elusive. Here, we show that the tumor microenvironment derived from the human esophageal squamous cell carcinoma (ESCC) cell line EC9706 can induce immature DCs (iDCs) differentiate toward endothelial cells, and become endothelial-like cells, but it has no obvious influence on mature DCs. During the course of endothelial-like differentiation of iDCs, a sustained activation of mitogen-activated protein kinase/extracelluar signal-regulated kinase1/2 (MAPK/ERK1/2) and cAMP response element-binding protein (CREB) was detected. Incubation of iDCs with MEK phosphorylation inhibitor PD98059 blocked the MAPK/ERK1/2 and CREB phosphorylation as well as the endothelial-like differentiation of iDCs. Inhibition of vascular endothelial growth factor-A (VEGF-A) in the microenvironment with its antibody blocked the endothelial-like differentiation and the phosphorylation of MAPK/ERK1/2 and CREB. These data suggest that MAPK/ERK1/2 signaling pathway activated by VEGF-A could mediate endothelial-like differentiation of iDCs in the ESCC microenvironment.

Coxsackievirus and adenovirus receptor promotes antitumor activity of oncolytic adenovirus H101 in esophageal cancer

Esophageal cancer is an intractable disease due to late diagnosis, high incidence of post-surgical locoregional recurrence and frequent distant metastasis. Oncolytic adenovirus (Ad) vectors are a promising method for cancer treatment. The H101 virus is a recombinant Ad which has replication-selective properties and replicates only in tumor cells. The coxsackievirus and adenovirus receptor (CAR) is considered a surrogate marker that monitors the outcome of Ad-mediated gene therapy. Accumulating evidence indicates that CAR expression levels are lower in various types of tumors such as ovarian, lung, breast and bladder when compared to their normal counterparts. In this study, we reported that trichostatin A (TSA) induced the expression of CAR in esophageal squamous cell carcinoma (ESCC) cell lines through the MAPK/ERK1/2 signaling pathway. The expression levels of CAR were positively related with the antitumor activity of H101. Our results suggest that TSA increases the antitumor activity of the oncolytic adenovirus H101 through the MAPK/ERK pathway.

VEGF-A not Ang2 mediates endothelial-like differentiation of immature DCs by ERK1/2 signaling in the microenvironment of human colon adenocarcinoma.

Endothelial-like differentiation of dendritic cells (DCs) is an interesting and significant phenomenon, which is worth further investigation. Here, we show that the tumor microenvironment derived from the supernatant of the SW620 human colon adenocarcinoma cell line and colon adenocarcinoma tissue homogenate can promote immature DCs (iDCs) to differentiate from the DC pathway toward endothelial cells, while the peri-carcinoma homogenate supernatant does not have this role. Inhibition of angiopoietin-2 (Ang2) in the supernatant by its antibody has no obvious influence on the endothelial-like differentiation. In contrast, inhibition of vascular endothelial growth factor-A (VEGF-A) blocked the differentiation. During the course of differentiation, a sustained activation of ERK1/2 was detected. PD98059 blocked the phosphorylation of ERK1/2 as well as the endothelial-like differentiation of iDCs. Inhibition of VEGF-A also blocked the phosphorylation of ERK1/2. These data suggest that VEGF-A not Ang2 mediates endothelial-like differentiation of iDCs by ERK1/2 signaling in the microenvironment of human colon adenocarcinoma.

Alternariol induces DNA polymerase β expression through the PKA-CREB signaling pathway.

Alternariol (AOH) is a mycotoxin of Alternaria alternata and can cause DNA damage and gene mutations. Low-dose and long-term treatment with AOH has been linked with incidence of esophageal carcinoma. DNA polymerase β (polβ) is a key enzyme in DNA base excision repair (BER). When it is overexpressed or mutated in cells, DNA polβ can cause genetic instability. Elevated DNA polβ has also been reported in several human cancers. Here, we report that AOH at 2, 10, 20 µM induces DNA polβ expression. In the process, protein kinase A (PKA) catalytic subunit activation, nuclear translocation and cAMP response element binding protein (CREB) phosphorylation are involved. AOH also increased CREB binding to the cAMP response element (CRE) consensus motif, which is present in the DNA polβ gene promoter. The PKA inhibitor H89 was able to block AOH-induced PKA-CREB activation, CREB DNA binding activity and decrease DNA polβ expression. Our results suggest that AOH can upregulate DNA polβ expression through the PKA-CREB signal transduction pathway.

VEGF‐A‐induced immature DCs not mature DCs differentiation into endothelial‐like cells through ERK1/2‐dependent pathway

Dendritic cells (DCs) are professional antigen‐presenting cells that play an important role in anti‐tumour immunity. Endothelial‐like differentiation of DCs is an interesting phenomenon. The specific role of vascular endothelial growth factor‐A (VEGF‐A) on the differentiation of immature DCs (iDCs) and mature DCs (mDCs) is worth further research. Here, we show that VEGF‐A can induce iDCs to differentiate into endothelial‐like cells (ELCs). But it has no obvious influence on mDCs. In the process of endothelial‐like differentiation of iDCs, a sustained activation of extracellular signal‐regulated kinase (ERK1/2) and cAMP response element binding protein (CREB) was detected. VEGF‐A induced the activation of ERK1/2, and led to the nuclear translocation of phosphorylation ERK1/2. Incubation of iDCs with the ERK1/2 upstream kinase MEK1/2 inhibitor PD98059, blocked the phosphorylation of ERK1/2 and CREB as well as the endothelial‐like differentiation of iDCs. These data suggest that VEGF‐A induces endothelial‐like differentiation of iDCs not mDCs through ERK1/2 signalling pathway. Copyright

Histone deacetylase inhibitor trichostatin A enhances the antitumor effect of the oncolytic adenovirus H101 on esophageal squamous cell carcinoma in vitro and in vivo

Replication-selective oncolytic virotherapy provides a novel modality to treat cancer by inducing cell death in tumor cells but not in normal cells. However, the utilization of oncolytic viruses as a stand-alone treatment is problematic due to their poor transduction efficiency in vivo. H101 was the first oncolytic adenovirus (Ads) to be approved by the Chinese FDA, and exhibits modest antitumor effects when applied as a single agent. The multiple histone deacetylase inhibitor trichostatin A (TSA) has been demonstrated to potently enhance the spread and replication of oncolytic Ads in several infection-resistant types of cancer. The present study aimed to investigate the antitumor effects of H101 in combination with TSA on esophageal squamous cell carcinoma (ESCC) in vitro and in vivo, and determine the mechanisms underlying these effects. H101 and TSA in combination increased the survival of mice harboring human ESCC cell line-tumor xenografts, as compared with mice treated with these agents individually. Therefore, TSA may enhance the antitumor effects of H101 in ESCC.

Identification of DAPK1 Promoter Hypermethylation as a Biomarker for Intra-Epithelial Lesion and Cervical Cancer: A Meta-Analysis of Published Studies, TCGA, and GEO Datasets

Background: Promoter hypermethylation in death-associated protein kinase 1 (DAPK1) gene has been long linked to cervical neoplasia, but the established results remained controversial. Here, we performed a meta-analysis to assess the associations of DAPK1 promoter hypermethylation with low-grade intra-epithelial lesion (HSIL), high-grade intra-epithelial lesion (HSIL), cervical cancer (CC), and clinicopathological features of CC. Methods: Published studies with qualitative methylation data were initially searched from PubMed, Web of Science, EMBASE, and China National Knowledge Infrastructure databases (up to March 2018). Then, quantitative methylation datasets, retrieved from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, were pooled to validate the results of published studies. Results: In a meta-analysis of 37 published studies, DAPK1 promoter hypermethylation progressively increased the risk of LSIL by 2.41-fold (P = 0.012), HSIL by 7.62-fold (P < 0.001), and CC by 23.17-fold (P < 0.001). Summary receiver operating characteristic curves suggested a potential diagnostic value of DAPK1 promoter hypermethylation in CC, with a large area-under-the-curve of 0.83, a high specificity of 97%, and a moderate sensitivity of 59%. There were significant impacts of DAPK1 promoter hypermethylation on histological type (odds ratio (OR) = 3.53, P < 0.001) and FIGO stage of CC (OR = 2.15, P = 0.003). Then, a pooled analysis of nine TCGA and GEO datasets, covering 13 CPG sites within DAPK1 promoter, identified eight CC-associated sites, six sites with diagnostic values for CC (pooled specificities: 74–90%; pooled sensitivities: 70–81%), nine loci associated with the histological type of CC, and all 13 loci with down-regulated effects on DAPK1 mRNA expression. Conclusion: The meta-analysis suggests that DAPK1 promoter hypermethylation is significantly associated with the disease severity of cervical neoplasia. DAPK1 methylation detection exhibits a promising ability to discriminate CC from cancer-free controls.