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.