BAT-26 instability, a sensitive marker for the high-frequency microsatellite instability (MSI-H) phenotype, was analyzed in samples of gastric cancer and in adjacent intestinal metaplastic mucosae. Although all MSI-H gastric cancer samples showed BAT-26 instability, as assessed using 12 dinucleotide microsatellite markers, BAT-26 instability was not found in the adjacent intestinal metaplastic mucosa in any of the samples.
The small GTPases RalA and RalB are members of the Ras family and activated downstream of Ras. Ral proteins are found in GTP‐bound active and GDP‐bound inactive forms. The activation process is executed by guanine nucleotide exchange factors, while inactivation is mediated by GTPase‐activating proteins (GAPs). RalGAPs are complexes that consist of a catalytic α1 or α2 subunit together with a common β subunit. Several reports implicate the importance of Ral in pancreatic ductal adenocarcinoma (PDAC). However, there are few reports on the relationship between levels of RalGAP expression and malignancy in PDAC. We generated RalGAPβ‐deficient PDAC cells by CRISPR‐Cas9 genome editing to investigate how increased Ral activity affects malignant phenotypes of PDAC cells. RalGAPβ‐deficient PDAC cells exhibited several‐fold higher Ral activity relative to control cells. They had a high migratory and invasive capacity. The RalGAPβ‐deficient cells grew more rapidly than control cells when injected subcutaneously into nude mice. When injected into the spleen, the RalGAPβ‐deficient cells formed larger splenic tumors with more liver metastases, and unlike controls, they disseminated into the abdominal cavity. These results indicate that RalGAPβ deficiency in PDAC cells contributes to high activities of RalA and RalB, leading to enhanced cell migration and invasion in vitro, and tumor growth and metastasis in vivo.
Dendritic cell-associated C-type lectin-2 (i.e., dectin-2) recognizes fungal polysaccharides, including a-mannan. Dectin-2emediated recognition of fungi, such as Candida albicans, leads to NF-kB activation, which induces production of inflammatory cytokines. However, the role of dectin-2 in skin wound healing remains unclear. In this study, we sought to determine how dectin-2 deficiency and the administration of a-mannan affected the wound healing process. Full-thickness wounds were created on the backs of wild type C57BL/6 and dectin-2edeficient mice. We analyzed wound closure, histological findings, and re-epithelialization. We also examined the neutrophilic inflammatory responses and neutrophil extracellular trap (NET)-osis at the wound sites after administration of a-mannan. The percent wound closure and re-epithelialization was significantly accelerated in dectin-2eknockout mice compared with wild-type mice on days 3 and 5 after wounding. In contrast, administration of a-mannan delayed wound closure in wild-type mice, and these responses were canceled in dectin-2eknockout mice. Furthermore, mice administered a-mannan, neutrophil infiltration was prolonged, and the expression of citrullinated histone, an indicator of NETosis, at the wound sites was accelerated. Administration of a neutrophil elastase inhibitor significantly improved the delayed wound healing caused by a-mannan. These results suggest that dectin-2 may have a deep impact on the skin wound healing process through regulation of neutrophilic responses.
Stomatin-like protein 2 (SLP-2) is associated with poor prognosis in several types of cancer, including pancreatic cancer (PC); however, the molecular mechanism of its involvement remains elusive. The present study aimed to elucidate the role of this protein in the development of PC. Human PC cell lines AsPC-1 and PANC-1 were transfected by a vector expressing SLP-2 shRNA. Analyses of cell proliferation, migration, invasion, chemosensitivity, and glucose uptake were conducted, while a mouse xenograft model was used to evaluate the functional role of SLP-2 in PC. Immunohistochemical analysis was retrospectively performed on human tissue samples to compare expression between the primary site (n=279) and the liver metastatic site (n=22). Furthermore, microarray analysis was conducted to identify the genes correlated with SLP-2.
In vitro
analysis demonstrated that cells in which SLP-2 was suppressed exhibited reduced cell motility and glucose uptake, while
in vivo
analysis revealed a marked decrease in the number of liver metastases. Immunohistochemistry revealed that SLP-2 was increased in liver metastatic sites. Microarray analysis indicated that this protein regulated the expression of glutamine-fructose-6-phosphate transaminase 2 (GFPT2), a rate-limiting enzyme of the hexosamine biosynthesis pathway. SLP-2 contributed to the malignant character of PC by inducing liver metastasis. Cell motility and glucose uptake may be induced via the hexosamine biosynthesis pathway through the expression of GFPT2. The present study revealed a new mechanism of liver metastasis and indicated that SLP-2 and its downstream pathway could provide novel therapeutic targets for PC.
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