AIM:To explore a novel method to isolate human nucleus pulposus mesenchymal stem cells (hNP-MSCs) in vitro and to identify their biological characteristics.METHODS:The explant culture method was employed to isolate hNP-MSCs from nucleus pulposus tissue obtained by percutaneous endoscopic lumbar discectomy (PELD).The isolated cells were passaged for purification and cultured in vitro followed by morphological observation.The cell proliferation ability was detected by CCK-8 assay.Growth curves of the cells were drawn and surface antigens were detected by flow cytometry.The cells at the 3rd~6th passages were induced for adipogenic, osteogenic and chondrogenic differentiation, and examined by oil red O staining, alizarin red staining and Alcian blue staining.RESULTS:The cells with self-renewal were obtained from nucleus pulposus tissue obtained by PELD.The results of flow cytometry analysis revealed that the cells were positive for CD29, CD44, CD90, CD73 and CD105, but negative for CD34 and CD45.The proliferative capacity was consistent with the growth characteristics of MSCs and multilineage differentiation potential was identified.CONCLUSION:A novel method to efficiently isolate and culture hNP-MSCs,PELD combined with explant culture method,was established, which would promote the study of regenerative medicine based on hNP-MSCs.

OBJECTIVETo investigate the association of gankyrin protein expression in colorectal cancer (CRC) with its prognosis.

METHODSClinical data and resection samples of 100 colorectal cancer patients identified by pathology undergoing resection in our department from June 2008 to June 2009 were collected. The gankyrin expression in CRC tissues and matched adjacent noncancerous tissues collected during the operation of 100 CRC cases was detected by immunohistochemical staining and Western blotting. The associations of gankyrin expression level with overall survival, clinicopathologic features were analyzed by Chi square test, Cox regression analysis, Kaplan-Meier analysis and log rank test.

RESULTSImmunohistochemical staining showed that the positive brown granules were mainly distributed in the cytoplasm, and nuclear immunostaining was observed in tissue samples of 29 cases, of whom 16 cases had distal metastasis [55.2% (16/29)]. The positive rate of gankyrin and the relative gray value of Western blotting in CRC tissues were 67% (67/100) and 0.69±0.23, respectively, which were significantly higher than those of 2 cm adjacent noncancerous tissues [6% (6/100) and 0.31±0.16] and 10 cm adjacent noncancerous tissues [1%(1/100) and 0.16±0.11] (all P<0.001). Patients with positive expression of gankyrin had worse survival than those with negative ones (41.8% vs. 72.7%, P=0.008). The gankyrin expression was associated to lymph node metastasis (P=0.005), tumor stage (P=0.001) and distal metastasis (P=0.002). Cox regression analysis showed that distal metastasis (P=0.004) and high expression of gankyrin (P=0.038) were independent risk factors for poor prognosis of patients with CRC.

CONCLUSIONUp-regulated expression of gankyrin is related to invasion and metastasis of human CRC, and gankyrin may be valuable in predicting prognosis.

Blotting, Western ; Colorectal Neoplasms ; Humans ; Kaplan-Meier Estimate ; Lymphatic Metastasis ; Postoperative Period ; Prognosis ; Proteasome Endopeptidase Complex ; Proto-Oncogene Proteins