A polymorphism in the promoter region of PD-L1 serves as a binding-site for SP1 and is associated with PD-L1 overexpression and increased occurrence of gastric cancer.

PD-L1 is a member of the B7 family co-inhibitory molecules and plays a critical role in tumor immune escape. In this study, we found a polymorphism rs10815225 in the PD-L1 promoter region was significantly associated with the occurrence of gastric cancer. The GG homozygous frequency was higher in the cancer patients than that in the precancerous lesions, which was higher than that in the health controls. This polymorphism locates in the binding-site of Sp1 transcription factor (SP1). The expression level of PD-L1 mRNA in the GG homozygous cancer patients was apparently higher than that in the GC heterozygotes. Luciferase reporter results showed that SP1 bonded to rs10815225 G-allelic PD-L1 promoter instead of C-allelic. Upregulation and knockdown of SP1 resulted in elevation and attenuation of PD-L1 in SGC-7901 cells, respectively. The chromatin immunoprecipitation results further confirmed the binding of SP1 to the promoter of PD-L1. Additionally, rs10815225 was found to be in disequilibrium with a functional polymorphism rs4143815 in the PD-L1 3'-UTR, and the haplotypes of these two polymorphisms were also markedly related to gastric cancer risk. These results revealed a novel mechanism underlying genetic polymorphisms influencing PD-L1 expression modify gastric cancer susceptibility.

Establishment of a cell line from a Japanese patient useful for generating an in vivo model of malignant pleural mesothelioma.

Malignant pleural mesothelioma is a refractory tumor with increasing incidence. In the present study, we established six mesothelioma cell lines possessing two allele deletions of the p16(INK4A) gene and one allele deletion of the neurofibromatosis type 2 gene, MM16, MM21, MM26, MM35, MM46 and MM56, from pleural effusion fluids or surgically resected tumors of Japanese patients. MM21, MM26 and MM46 cells failed to develop tumors in BALB/c-nude mice following subcutaneous inoculation. MM16 and MM35 cells slowly generated tumors at the site of subcutaneous inoculation in BALB/c-nude mice, but lost the expression of mesothelioma-related markers such as calretinin, D2-40 and Wilms' tumor 1 in the subcutaneous tumors. On the other hand, MM56 cells rapidly generated tumors with the expression of calretinin and D2-40 in BALB/c-nude mice following subcutaneous inoculation. In addition, orthotopic implantation of MM56 cells into BALB/c-nude mice developed diffusely growing thoracic tumors by 3 weeks after implantation. Pleural effusions were observed in these mice 4 weeks after implantation. Thoracic tumors invaded aggressively into the chest wall 5 weeks after implantation and often metastasized into the lung, rib, peritoneum and pericardial cavity. On the pleural surface, MM56 cells were growing as single or multiple cell layers with the reactive mesothelium of recipient mice. These results indicate that MM56 cells can behave in a manner characteristic of human malignant pleural mesothelioma in the thoracic cavity of BALB/c-nude mice. The in vivo model using MM56 cells may be useful for studying the biological behavior of malignant pleural mesothelioma and developing its diagnostic and therapeutic strategies.

Fascin expression in human embryonic, fetal, and normal adult tissue.

This study investigates the distribution of fascin in human embryonic, fetal, and normal adult tissues. Tissue microarray technology was used to perform immunohistochemical experiments on human embryos and fetuses at 4-22 weeks of gestation and adult specimens. Fascin was widely expressed in the nervous system. At 4 weeks of gestation, fascin was present in the neural tube. At 8-12 weeks of gestation, homogenous gene expression was seen in cells of the cerebellum and gastrointestinal tract. In later developmental stages and in adults, Purkinje cells of the cerebellum and glandular epithelium of the gastrointestinal tract showed no expression. Fascin was expressed in the cortex and medulla of the adrenal gland at 8-12 weeks of gestation, whereas immunoreactivity decreased from the zona glomerulosa through the zona reticularis and was essentially negative in the adrenal medulla of adults. Significant expression of fascin was seen throughout development in neurons, follicular dendritic cells of lymphoid tissue, basal layer cells of stratified squamous epithelia, mesenchyme, and vascular endothelial cells. Simple columnar epithelia of the biliary duct, colon, ovary, pancreas, and stomach were all negative for fascin expression. These results show that expression of fascin is time specific and highly tissue specific. Parallels between fascin expression in embryogenesis and carcinogenesis are discussed.

Expression of fascin in thyroid neoplasms: a novel diagnostic marker.

PURPOSE: Fascin, an actin-bundling protein, is markedly upregulated in several epithelial tumors and its expression often correlates with high-grade, extensive invasion, and distant metastasis. However, reports about fascin expression in endocrine tumors remain rare. The aim of the present study was to assess the diagnostic significance of fascin in thyroid neoplasms. METHODS: Thyroid samples from 177 cases were examined for fascin and Ki-67 expression by immunohistochemistry. RESULTS: Fascin immunoreactivity was negative in normal follicles and nodular goiter. Fascin immunostaining was positive in 62.1% (41/66) of thyroid carcinomas and 26.4% (19/72) of thyroid adenomas; the difference being significant (P < 0.0001). In thyroid papillary carcinoma, upregulation of fascin was associated with both the Ki-67 labeling index and the occurrence of lymph node metastasis. CONCLUSION: Fascin may be a novel marker to distinguish thyroid carcinoma from benign lesions and may be involved in the proliferation and metastasis of papillary carcinoma.

F806 Suppresses the Invasion and Metastasis of Esophageal Squamous Cell Carcinoma via Downregulating F-Actin Assembly-Related Rho Family Proteins.

Invasion and metastasis are critical pathological and mortal processes in esophageal squamous cell carcinoma (ESCC). Novel drugs, targeting the two cancer migration stages, will augment the treatment options for ESCC therapy and improve overall survival. A novel natural macrolide F806 specifically promotes apoptosis of various ESCC cells. However, whether F806 can inhibit metastasis of ESCC cells needs further evaluation. Here, our data showed that F806 inhibits dynamic F-actin assembly and then suppresses the migration of ESCC cells in vitro and their invasion and metastasis in vivo. The correlation between cancer migration and actin cytoskeleton assembly was consistent with the ability of F806 to prevent the aggregation of Paxillin, an essential protein for focal adhesion formation through binding to the ends of actin filaments. Furthermore, F806 downregulated the expression and activity of the Rho family proteins cell division cycle 42 (CDC42), RAC family small GTPase 1 (RAC1), and RAS homolog family member A (RHOA). Taken together, these results suggest that F806 can suppress cancer invasion and metastasis via interrupting the assembly of migration components involving F-actin.

Ezrin Ser66 phosphorylation regulates invasion and metastasis of esophageal squamous cell carcinoma cells by mediating filopodia formation.

BACKGROUND: Ezrin, links the plasma membrane to the actin cytoskeleton, and plays an important role in the development and progression of human esophageal squamous cell carcinoma (ESCC). However, the roles of ezrin S66 phosphorylation in tumorigenesis of ESCC remain unclear. METHODS: Distribution of ezrin in membrane and cytosol fractions was examined by analysis of detergent-soluble/-insoluble fractions and cytosol/membrane fractionation. Both immunofluorescence and live imaging were used to explore the role of ezrin S66 phosphorylation in the behavior of ezrin and actin in cell filopodia. Cell proliferation, migration and invasion of ESCC cells were investigated by proliferation and migration assays, respectively. Tumorigenesis, local invasion and metastasis were assessed in a nude mouse model of regional lymph node metastasis. RESULTS: Ezrin S66 phosphorylation enhanced the recruitment of ezrin to the membrane in ESCC cells. Additionally, non-phosphorylatable ezrin (S66A) significantly prevented filopodia formation, as well as caused a reduction in the number, length and lifetime of filopodia. Moreover, functional experiments revealed that expression of non-phosphorylatable ezrin (S66A) markedly suppressed migration and invasion but not proliferation of ESCC cells in vitro, and attenuated local invasion and regional lymph node metastasis, but not primary tumor growth of ESCC cells in vivo. CONCLUSION: Ezrin S66 phosphorylation enhances filopodia formation, contributing to the regulation of invasion and metastasis of esophageal squamous cell carcinoma cells.

Expression of NGAL and NGALR in human embryonic, fetal and normal adult tissues.

This study investigated the distribution of neutrophil gelatinase-associated lipocalin (NGAL) and neutrophil gelatinase-associated lipocalin receptor (NGALR) in human embryonic, fetal and normal adult tissues. Tissue microarray technology was used to perform immunohistochemical examination on human embryos, fetuses at 4-22 weeks of gestation and adult tissue specimens. Results demonstrated that during the development of the nervous system, NGALR was prevalent in the neural tube and cerebrum, and NGAL was only detected in the stellate cells of the cerebrum and the Purkinje cells of the cerebellum. NGAL and NGALR were expressed in the lung alveolar epithelium and in the gastrointestinal tract in embryos, but were almost undetectable in later developmental stages. In the embryonic adrenal glands, the two proteins demonstrated moderate positivity in the cortex and the medulla. In adults, NGAL was particularly present in the cells of the inner and outer layers of the cortex and was absent in the medulla, while NGALR exhibited strong positivity in the cortex and the medulla. Evident expression of NGAL and NGALR was observed throughout development in the neutrophil-rich sites, the renal tubule epithelium and certain gland epithelia of the gastrointestinal tract, but was undetectable in the heart, liver and thyroid gland. Taken together, these results demonstrated that the expression of NGAL and NGALR was time-specific and highly tissue­specific. Correlations between their expression in embryogenesis and carcinogenesis should be examined.

Expression of ezrin in human embryonic, fetal, and normal adult tissues.

Ezrin, which cross-links the cytoskeleton and plasma membrane, was involved in a wide variety of cellular processes. Here, to investigate the distribution of ezrin, tissue microarray technology was employed to perform immunohistochemical experiments on human embryos, fetuses at 4 to 22 weeks' gestation, and adult tissue specimens. Results showed that ezrin was widely expressed in the gastrointestinal tract throughout the human developmental stages studied. At 6 to 8 weeks' gestation, ezrin was found in epithelial cells, and this staining pattern was particularly pronounced in the brush border of mature absorptive cells lining the villus in later developmental stages and adult tissues. Throughout neural development, ezrin was only expressed in the neural tube at 4 weeks' gestation. Ezrin was also detected in the cortex and medulla of the adrenal gland at 8 to 12 weeks' gestation, whereas its immunoreactivity was increased from the zona glomerulosa through the zona reticularis and was essentially undetectable in the adrenal medulla of adult tissues. Significant expression of ezrin was seen throughout development in the kidney, spleen, lymph nodes, and cells of stratified squamous epithelia. However, ezrin was undetectable in lung, liver, heart, and blood vessels. These results demonstrated that the expression pattern of ezrin was highly time specific and tissue specific.

Comparison between colorectal low- and high-grade mucinous adenocarcinoma with MUC1 and MUC5AC.

AIM: To explore useful prognostic factors for mucinous adenocarcinoma (MAC) in the colon and rectum. METHODS: MAC was divided into low- and high-grade types based on the degree of structural differentiation; low-grade MAC arisen from well to moderately differentiated adenocarcinoma and papillary carcinoma, and high-grade MAC from poorly differentiated adenocarcinoma and signet ring cell carcinoma. Immunohistochemically, the expression of 2 types of MUC1 (MUC1/DF and MUC1/CORE), MUC2, 2 types of MUC5AC (MUC5AC/CHL2 and HGM), MUC6, CDX2, and CD10 was examined in 16 cases of MAC consisting of 6 low- and 10 high-grade types. RESULTS: MUC1/DF3 was expressed in 3 of 6 low-grade MAC (50%) and 10 of 10 high-grade MAC (100%). MUC1/CORE was expressed in 1 of 6 low-grade MAC (16.7%) and 7 of 10 high-grade MAC (70%). MUC2 was expressed in all MAC regardless of the grade. MUC5AC was expressed in 6 of 6 low-grade MAC (100%) and 4 of 10 high-grade MAC (40%). HGM was expressed in 5 of 6 low-grade MAC (83.3%) and 6 of 10 high-grade MAC (60%). Expression of MUC6 and CD10 was undetected in all MAC regardless of the grade. CDX2 was expressed in 5 of 6 low-grade MAC (83.3%) and 7 of 10 high-grade MAC (70%). Taken together, MUC1/DF3 was expressed significantly more frequently in high-grade MAC than in low-grade, and MUC5AC/CHL2 was expressed significantly more frequently in low-grade MAC than in high-grade. CONCLUSION: It is proposed that MUC1/DF3 and MUC5AC/CHL2 immunostaining is useful to discriminate high-grade MAC from low-grade MAC.

Comparison between mucinous cystic neoplasm and intraductal papillary mucinous neoplasm of the branch duct type of the pancreas with respect to expression of CD10 and cytokeratin 20.

OBJECTIVE: Mucinous cystic neoplasm (MCN) and intraductal papillary mucinous neoplasm of the branch duct type (IPMN-BD) differ in biological and clinical behaviors, but MCN is often misdiagnosed as IPMN-BD. The purpose of this study was to find useful markers for the differential diagnosis of MCN and IPMN-BD. METHODS: Immunohistochemically, the expression of the 2 types of mucin (MUC) 1 (MUC1/DF3 and MUC1/CORE), MUC2, MUC5AC, MUC6, human gastric mucin (HGM), caudal-related homeobox transcription factor 2 (CDX2), CD10, cytokeratin (CK) 7, and CK20 was examined in 7 cases of MCN and 16 cases of IPMN-BD. RESULTS: Expression frequencies in MCN and IPMN-BD were 100% versus 44% for MUC1/DF3, 86% versus 31% for MUC1/CORE, 57% versus 19% for MUC2, 86% versus 100% for MUC5AC, 57% versus 88% for MUC6, 86% versus 100% for HGM, 57% versus 0% for CDX2, 71% versus 0% for CD10, 100% versus 69% for CK7, and 86% versus 6% for CK20. CONCLUSIONS: Mucin 1/DF3, MUC1/CORE, CDX2, CD10, and CK20 were expressed significantly more frequently in MCN than in IPMN-BD. In particular, CD10 and CK20 showed marked differences in immunohistochemical sensitivity and specificity between MCN and IPMN-BD. It is therefore proposed that CD10 and CK20 may be used for the differential diagnosis of MCN and IPMN-BD.