It is largely recognized that fibroblast activation protein (FAP) is expressed in cancer-associated fibroblasts (CAFs) of many human carcinomas. Furthermore, FAP was recently also reported to be expressed in carcinoma cells of the breast, stomach, pancreatic ductal adenocarcinoma, colorectum, and uterine cervix. The carcinoma cell expression pattern of FAP has been described in several types of cancers, but the role of FAP in oral squamous cell carcinoma (OSCC) is unknown. The role of endogenous FAP in epithelium-derived tumors and molecular mechanisms has also not been reported. In this study, FAP was found to be expressed in carcinoma cells of OSCC and was upregulated in OSCC tissue samples compared with benign tissue samples using immunohistochemistry. In addition, its expression level was closely correlated with overall survival of patients with OSCC. Silencing FAP inhibited the growth and metastasis of OSCC cells in vitro and in vivo. Mechanistically, knockdown of FAP inactivated PTEN/PI3K/AKT and Ras-ERK and its downstream signaling regulating proliferation, migration, and invasion in OSCC cells, as the inhibitory effects of FAP on the proliferation and metastasis could be rescued by PTEN silencing. Our study suggests that FAP acts as an oncogene and may be a potential therapeutic target for patients with OSCC.
Although increasing evidence indicated that the deregulation of microRNAs (miRNAs) contributes to tumorigenesis and invasion, little is known about the role of miR-637 in human gliomas. In the present study, we found that the expression level of miR-637 was significantly reduced in clinical glioma tissues compared with normal brain tissues. Moreover, we revealed that the introduction of miR-637 dramatically suppressed glioma cell growth, migration and invasion in vitro and in vivo. Further studies revealed that Akt1 is a direct target gene of miR-637. Silencing of Akt1 inhibited the growth and invasion of glioma cells by decreasing phosphorylated Akt, β-catenin, phosphorylated Foxo1 and Cyclin D1 and inducing the expression of Foxo1, which was consistent with the effect of miR-637 overexpression. Suppressed expression of miR-637 and increased Akt1 protein levels were correlated with unfavorable progression and poor prognosis, respectively, and a negative relationship between the miR-637 expression and Akt1 protein levels was observed in gliomas. Our findings provide new insights into the role of miR-637 in the development of gliomas, and implicate the potential application of miR-637 in cancer therapy.
miR-374a has been reported to function as an oncogene during tumor pathogenesis. In this study, miR-374a is observed to reduce nasopharyngeal carcinoma (NPC) cell proliferation, migration, invasion, metastasis and cisplatin (DDP) resistance in vitro and in vivo. Mechanistic analyses indicate that miR-374a directly targets CCND1 to inactivate pPI3K/pAKT/c-JUN forming a negative feedback loop, as well as suppressing downstream signals related to cell cycle progression and epithelial-mesenchymal transition (EMT). Interestingly, we also observed that miR-374a direct targeting of CCND1 is modulated by tumor suppressor PDCD4 via suppressing pPI3K/pAKT/c-JUN signaling. In clinical specimens, miR-374a was positively and negatively correlated with expression of PDCD4 and CCND1, respectively. Our studies are the first to demonstrate that the miR-374a-CCND1-pPI3K/AKT-c-JUN feedback loop induced by PDCD4 supresses NPC cell growth, metastasis and chemotherapy resistance.
These results suggest that a unique genetic mechanism of developmental instability may obtain in CL/P individuals with a positive family history of clefting.
Leukemia stem cells (LSCs) are considered to be the main reason for relapse and are also regarded as a major hurdle for the success of acute myeloid leukemia chemotherapy. Thus, new drugs targeting LSCs are urgently needed. Triptolide (TPL) is cytotoxic to LSCs. Low dose of TPL enhances the cytotoxicity of idarubicin (IDA) in LSCs. In this study, the ability of TPL to induce apoptosis in leukemic stem cell (LSC)-like cells derived from acute myeloid leukemia cell line KG1a was investigated. LSC-like cells sorted from KG1a were subjected to cell cycle analysis and different treatments, and then followed by in vitro methyl thiazole tetrazolium bromide cytotoxicity assay. The effects of different drug combinations on cell viability, intracellular reactive-oxygen species (ROS) activity, colony-forming ability and apoptotic status were also examined. Combination index-isobologram analysis indicates a synergistic effect between TPL and IDA, which inhibits the colony-forming ability of LSC-like cells and induces their apoptosis. We further investigated the expression of Nrf2, HIF-1α and their downstream target genes. LSC-like cells treated with both TPL and IDA have increased levels of ROS, decreased expression of Nrf2 and HIF-1α pathways. Our findings indicate that the synergistic cytotoxicity of TPL and IDA in LSCs-like cells may attribute to both induction of ROS and inhibition of the Nrf2 and HIF-1α pathways.
The pluripotency gene Nanog is not expressed in normal adult tissues but is overexpressed in some human cancers. However, the tumorigenic roles of Nanog remain unclear. The ectopic expression of Nanog is not sufficient to induce spontaneous tumors in mice but can promote metastasis of established tumors by activating the expression of metastatic genes. The expression of Nanog in mouse skin activates tumor suppressor p53, leading to the differentiation of epidermal stem cells. In the absence of p53, Nanog induces spontaneous squamous cell carcinoma, identifying a novel role of Nanog in tumorigenesis. Therefore, the induction of p53 and differentiation in Nanog-expressing skin suppresses the tumorigenic activities of Nanog, which include the induction of DNA double-stranded break damage. Notably, Nanog interacts with the KRAB-associated protein 1 (KAP1) and inhibits its sumoylation activity, impairing KAP1-mediated chromatin remodeling, which is important for efficiently activating DNA damage response. In summary, Nanog is an oncogene with multiple roles in promoting tumorigenesis and metastasis.
Only Ai-ICs, not all ICs, could trigger IgG-mediated PSA, which could be characterised by the above simple methods. The occurrence and severity of PSA was associated with the instantaneous concentration of antigen in the peripheral blood in the presence of antibody.
This paper presents the development of an analytical model of cutting forces in peripheral milling of curved surfaces. The eVect of the workpiece curvature is taken into account in the model construction. Based on the relationship of diVerential cutting forces and chip load, the total cutting forces are formulated by integration of the diVerential cutting forces along the cutting¯utes in the feed and cross-feed directions. This formulation leads to an explicit expression for the force waveforms as algebraic functions of cutter variables, process parameters, machining con®guration and workpiece geometry. Experiments are performed over a wide range of conditions to verify the model and meanwhile the eVects of the process parameters on the cutting forces are revealed. The presented model facilitates force estimation and provides a basis for the analysis, prediction and improvement of surface accuracy in peripheral milling of curved surfaces.
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