ß-Catenin/LEF1 transactivates the microRNA-371-373 cluster that modulates the Wnt/ß-catenin-signaling pathway.

The microRNA-371-373 (miR-371-373) cluster is specifically expressed in human embryonic stem cells (ESCs) and is thought to be involved in stem cell maintenance. Recently, microRNAs (miRNAs) of this cluster were shown to be frequently upregulated in several human tumors. However, the regulatory mechanism for the involvement of the miR-371-373 cluster in human ESCs or cancer cells remains unclear. In this study, we explored the relationship between this miRNA cluster and the Wnt/ß-catenin-signaling pathway, which has been shown to be involved in both stem cell maintenance and tumorigenesis. We show that miR-371-373 expression is induced by lithium chloride and is positively correlated with Wnt/ß-catenin-signaling activity in several human cancer cell lines. Mechanistically, three TCF/LEF1-binding elements (TBEs) were identified in the promoter region and shown to be required for Wnt-dependent activation of miR-371-373. Interestingly, we also found that miR-372&373, in turn, activate Wnt/ß-catenin signaling. In addition, four protein genes related to the Wnt/ß-catenin-signaling pathway were identified as direct targets of miR-372&373, including Dickkopf-1 (DKK1), a well-known inhibitor of Wnt/ß-catenin signaling. Using a lentiviral system, we showed that overexpression of miR-372 or miR-373 promotes cell growth and the invasive activity of tumor cells as knockdown of DKK1. Taken together, our study demonstrates a novel ß-catenin/LEF1-miR-372&373-DKK1 regulatory feedback loop, which may have a critical role in regulating the activity of Wnt/ß-catenin signaling in human cancer cells.

Huge nasopharyngeal angiofibroma with intracranial extension: change in the dura mater and choice of surgical management.

We aimed to review (1) the imaging changes in the dura mater in cases of huge, lobulated juvenile nasopharyngeal angiofibroma, and (2) the choice of surgical management. Imaging from four cases of juvenile nasopharyngeal angiofibroma showed extrapharyngeal extension of the tumour. The sphenoid sinus, sella turcica and clivus were extensively eroded, and the tumour had spread deep into the cranial fossa. In three cases, intracranial exploration was performed to treat the intracranial tumour lobule. Subsequently, the tumours were removed using extracranial approaches. No perforation of the dura mater was found in these three cases, although the dura mater in the superior orbital fissure was congested, haemorrhagic and solid. Pre-operative imaging for two cases (i.e. the first operation for one and the second operation for the other) revealed no dura mater perforation. A transantral approach via a midfacial degloving incision was used to remove these tumours completely. We conclude that change in the dura mater is a crucial indication for the choice of management. If the dura mater is intact, a transantral approach via a midfacial degloving incision may remove the tumour successfully.

[Effect of an improved rice soup culture medium on Candida albicans forming chlamydospore].

Three types of culture medium that stimulated Candida albicans to form chlamydospore were compared with the improved rice soup culture medium. The results were that the effect of the improved rice soup culture medium on stimulating C. albicans to form chlamydospore was better than the effects of others; a large number of chlamydospores could be gotten in 18 h. The results indicate that this method, the improved rice soup culture medium, is easy, simple, and economic. A method for making the teaching slide of C. albicans forming chlamydospore was also introduced.