Inhibitory roles of miR­9 on papillary thyroid cancer through targeting BRAF.

MicroRNA­9 (miR­9) is reported to be underexpressed in papillary thyroid carcinoma (PTC) tissues; however, the molecular mechanisms underlying the implication of miR­9 in PTC have yet to be elucidated. The present study aimed to explore the potential roles of miR­9 in PTC. PTC tissue samples and paired non­cancerous adjacent tissues were collected from 60 patients with PTC. The human TPC­1 thyroid gland papillary carcinoma cell line was used to investigate the molecular mechanisms underlying the roles of miR­9 in PTC. The levels of miR­9 and its downstream target gene BRAF were detected through reverse transcription­quantitative polymerase chain reaction. MTT assay and flow cytometry were performed to evaluate cell viability and apoptosis, respectively. A mouse xenograft tumor model was established to observe the effects of miR­9 on thyroid gland tumorigenesis in vivo. The present study revealed that the expression of miR­9 was significantly reduced in PTC tissues compared with paired normal tissues. In addition, miR­9 upregulation suppressed the expression of BRAF in TPC­1 cells in vitro. Luciferase reporter assay demonstrated that BRAF may be a direct target gene of miR­9 in TPC­1 cells. In addition, following transfection with miR­9 mimics, the viability of TPC­1 cells was suppressed and their apoptosis was enhanced; conversely, transfection with miR­9 inhibitor exerted the opposite effects in vitro. miR­9 overexpression or downregulation also affected in vivo PTC tumorigenesis in athymic mice. The present findings suggested that miR­9 may suppress the viability of PTC cells and inhibit tumor growth through directly targeting the expression of BRAF in PTC.

MicroRNA-1298 is regulated by DNA methylation and affects vascular smooth muscle cell function by targeting connexin 43.

AIMS: Growing evidence links microRNA to the process of peripheral vascular disease. Recently, we have found that microRNA-1298(miR-1298) is one of the most significantly down-regulated microRNAs in human arteries with arteriosclerosis obliterans (ASO) of the lower extremities. However, little is known regarding its role in the process of ASO. The present study aimed to investigate the expression, regulatory mechanisms, and functions of miR-1298 in the process of ASO. METHODS AND RESULTS: Using quantitative reverse-transcription PCR and in situ hybridization assays, miR-1298 was observed predominantly expressed in the vascular smooth muscle cells (VSMCs) and was significantly down-regulated in ASO compared with normal arteries. Pyrosequencing analysis revealed that the miR-1298 DNA upstream of CpG sites were hypermethylated in ASO compared with normal arteries. Next, the luciferase reporter assay revealed that miR-1298 down-regulation is related with upstream DNA CpG site hypermethylation. Introducing a miR-1298 mimic into cultured VSMCs significantly attenuated cell proliferation and migration. Connexin 43 (Cx43) was validated to be a functional target of miR-1298 that was involved in the miR-1298-mediated cellular effects. Finally, lentivirus-mediated delivery of miR-1298 and its target Cx43 into a rat carotid balloon injury model indicated that re-overexpression of miR-1298 significantly decreased neointimal formation by targeting connexin 43. CONCLUSION: Our data demonstrate a specific role of the upstream DNA methylation/miR-1298/Cx43 pathway in regulating VSMC function and suggest that modulation of miR-1298 levels may offer a novel therapeutic approach for ASO.

[Substitute valve at popliteal vein in treating deep venous valve insufficiency of lower extremities].

OBJECTIVE: To study the effectiveness of substitute valve at the popliteal vein in treatment of deep venous valve insufficiency of lower extremities. METHODS: From January 1996 to August 2002, 27 patients were diagnosed having deep venous valve insufficiency of lower extremities by color Doppler and radiography with an average disease course of 17.4 years. All 27 patients had varicose vein, 25 pain, 22 swelling, 25 pigmentation in ankle area and 19 chronic ulcerations. Two cases had been treated with great saphenous vein ligation and striping. Average vein pressure in resting position was (11.00 +/- 0.73) kPa, and the ambulatory venous pressure was (9.14 +/- 0.68) kPa. All patients were treated with substitute valve at the popliteal vein, and great saphenous vein ligation and stripping, some were treated with subfascial endoscopic perforating veins ablation. RESULTS: The average ambulatory venous pressure after operation was (5.94 +/- 0.82) kPa, were significantly different from that before operation(P < 0.01). The curative results were satisfactory, and all symptom and physical sign disappeared. After a mean follow-up period of 2-6 years, 21 cases had satisfactory results. CONCLUSION: Substitute valve at the popliteal vein have the value of widespread application.