干细胞技术治疗糖尿病的研究进展与应用前景

Relationship between vascular endothelial cells and pancreatic islet development and stem cell differentiation

As the main components of the pancreatic islet niche, endothelial cells participate in many processes of pancreatic development, including pancreatic cell fate decision, endocrine pancreatic cell differentiation and proliferation, and spatial distribution of the pancreas. On different occasions, endothelial cells play disparate roles by cross-talking with islet cells to influence endocrine pancreatic cell differentiation and islet morphology and function. Cytokines such as hepatocyte growth factor and sphingosine-1-phosphate as well as the extracellular matrixes such as laminin and collagen Ⅳ, which are produced and/or secreted by endothelial cells, play important roles in the regulation of islet development and function. Furthermore, endothelial cells are involved in the balance between self-renewal and differentiation of stem cells. Application of endothelial cells to induce the differentiation of stem cells into functional islet cells may be one of the most promising approaches to cell replacement therapy for diabetes.

Correlation of expression of Nanog, Oct-4 and SOX-2 with tumor metastasis in colonic cancer

AIM: To investigate the expression of Nanog, Oct-4 and SOX-2 in colonic carcinoma and to analyze their relationship with tumor metastasis.

METHODS: Immunohistochemistry was used to evaluate the expression of Nanog, Oct-4 and SOX-2 in 80 colonic cancer surgical specimens. The correlation of Nanog, Oct-4 and SOX-2 expression with tumor histological differentiation, T stage, N stage and metastasis was analyzed.

RESULTS: Thirty-five patients had metastasis. The positive rates of SOX-2, Oct-4 and Nanog expression were significantly higher in the metastasis group than in the non-metastasis group (48.57% vs 17.78%, 51.43% vs 13.33%, 60% vs 26.67%, all P < 0.05). Nanog expression was significantly correlated with differentiation (P = 0.001), but expression of Nanog, Oct-4 and SOX-2 was not associated with T stage or N stage. Metastatic rate was higher in patients with positive expression of the three markers than in those with negative expression. Survival analysis showed that the time to develop metastasis was significant different among patients with differential expression of the three markers (P = 0.0001).

CONCLUSION: The expression of Nanog, Oct-4 and SOX-2 in tumor tissue can predict the postoperative metastasis of colonic cancer. Nanog, Oct-4 and SOX-2 are promising predictors for metastasis of colonic cancer.