Combined Secretomics and Transcriptomics Revealed Cancer-Derived GDF15 is Involved in Diffuse-Type Gastric Cancer Progression and Fibroblast Activation.

Gastric cancer is classified into two subtypes, diffuse and intestinal. The diffuse-type gastric cancer (DGC) has poorer prognosis, and the molecular pathology is not yet fully understood. The purpose of this study was to identify functional secreted molecules involved in DGC progression. We integrated the secretomics of six gastric cancer cell lines and gene expression analysis of gastric cancer tissues with publicly available microarray data. Hierarchical clustering revealed characteristic gene expression differences between diffuse- and intestinal-types. GDF15 was selected as a functional secreted molecule owing to high expression only in fetal tissues. Protein expression of GDF15 was higher in DGC cell lines and tissues. Serum levels of GDF15 were significant higher in DGC patients as compared with healthy individuals and chronic gastritis patients, and positively correlated with wall invasion and lymph node metastasis. In addition, the stimulation of GDF15 on NIH3T3 fibroblast enhanced proliferation and up-regulated expression of extracellular matrix genes, which were similar to TGF-ß stimulation. These results indicate that GDF15 contributes to fibroblast activation. In conclusion, this study revealed that GDF15 may be a novel functional secreted molecule for DGC progression, possibly having important roles for cancer progression via the affecting fibroblast function, as well as TGF-ß.

[Alternative Splicing Detection as a Biomarker for Cancer Diagnosis: A Novel Progressive Mechanism of Acute Lymphoblastic Leukemia with Alternative Splicing as a Biomarker Candidate].

Alternative splicing is an important mechanism that links to transcription and contributes to protein diversity. Disturbed alternative splicing is frequently observed in cancers, but its precise mechanism remains largely unknown. FUSE-binding protein (FBP) -interacting repressor (FIR) is a transcriptional repressor of the c-myc gene. Previous studies indicated that a splice variant of FIR, FIRΔexon2, that lacks exon2 in the transcriptional repressor domain, was increased in colorectal cancers, hepatocellular carcinomas, and leukemia cells. Furthermore, FIRΔexon2 activated c-myc transcription by disabling wild-type FIR as a dominant-negative form of FIR. Recently, somatic mutations of the SF3B1 (SAP155) gene, a subunit of the SF3B spliceosome complex, were found in myelodysplastic leukemia. In this study, FIR heterozygous knockout (FIR(+/-)) was established as a dominant-negative model of FIR in the C57BL/6 mouse. FIR(+/-) mice showed an increased c-myc mRNA expression level, particularly in peripheral blood, although FIR(+/-) mice had no apparent pathogenic phenotype. Therefore, an increased c-myc mRNA expression level alone is not enough for leukemogenesis. Nevertheless, FIR(+/-)TP53(-/-) mice generated acute T-cell lymphoblastic leukemia (T-ALL) with increased organ and/or bone marrow invasion. In conclusion, alternative splicing of FIR, generating FIRΔexon2, contributes to not only colorectal carcinogenesis but also leukemogenesis independent of the c-Myc activation pathway. Finally, we will discuss our hypothesis that FIRΔexon2 interferes with FBW7, that FIRΔexon2 inhibits PP1 in the EGFR pathway, and that FIR haploinsufficiency is potentially associated with protein expression through transcriptional and post-transcriptional mechanisms.

The FLS (fatty liver Shionogi) mouse reveals local expressions of lipocalin-2, CXCL1 and CXCL9 in the liver with non-alcoholic steatohepatitis.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) encompasses a wide spectrum of diseases, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), which carries a significant risk of progression to cirrhosis and hepatocellular carcinoma. Since NASH is a progressive but reversible condition, it is desirable to distinguish NASH from simple steatosis, and to treat NASH patients at an early stage. To establish appropriate diagnosis and therapy, the pathological mechanisms of the disease should be elucidated; however, these have not been fully clarified for both NASH and simple steatosis. This study aims to reveal the differences between simple steatosis and NASH. METHODS: This study used fatty liver Shionogi (FLS) mice as a NASH model, for comparison with dd Shionogi (DS) mice as a model of simple steatosis. Genome-wide gene expression analysis was performed using Affymetrix GeneChip Mouse Genome 430 2.0 Array, which contains 45101 probe sets for known and predicted genes. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry were used to investigate gene expression changes and protein localizations. RESULTS: DNA microarray analysis of the liver transcriptomes and qRT-PCR of both types of mice revealed that LCN2, CXCL1 and CXCL9 mRNAs were overexpressed in FLS mouse livers. Immunohistochemistry showed that CXCL1 protein was mainly localized to steatotic hepatocytes. CXCL9 protein-expressing hepatocytes and sinusoidal endothelium were localized in some areas of inflammatory cell infiltration. Most interestingly, hepatocytes expressing LCN2, a kind of adipokine, were localized around almost all inflammatory cell clusters. Furthermore, there was a positive correlation between the number of LCN2-positive hepatocytes in the specimen and the number of inflammatory foci. CONCLUSIONS: Overexpression and distinct localization of LCN2, CXCL1 and CXCL9 in the liver of fatty liver Shionogi mice suggest significant roles of these proteins in the pathogenesis of NASH.