Correlation of matrix metalloproteinase－2, －9, tissue inhibitor－1 of matrix metalloproteinase and CD44 variant 6 in head and neck cancer metastasis

This study aimed to explore the molecular mechanism in tumor invasion and metastasis. The expression of matrix metalloproteinase-2, -9 (MMP-2, MMP-9), tissue inhibitor-1 of matrix metalloproteinase (TIMP-1), cell adhesion molecule 44 variant 6 (CD44v6), HER2/neu and p53 was investigated in 154 patients with head and neck squamous cell carcinoma (SCC) by ABC and ImmunoMax immunohistochemical method. Their clinical relevance and correlation were analysed. The expression of MMP-2, MMP-9, TIMP-1, CD44v6, HER2/neu and p53 was found in cancer cells in 87.01%, 85.71%, 68.18%, 98.05%, 55.19% and 50.65% cases respectively. Linear regression and correlation analysis revealed that there was close positive relationship (P<0.05) between the expression of MMP-2 and MMP-9, TIMP-1 and CD44v6, HER2/neu and MMP-9, MMP-2 and p53. Up-regulation of MMP-2 was accompanied by advanced T stage (P<0.01). There was also a trend of MMP-2 expression being related with tumor metastasis. Increased expression of HER2/neu was found in patients with tumor recurrence(P<0.05). The expression of TIMP-1 was higher in laryngeal cancer than that in pharyngeal cancer, and higher in keratinizing and non-keratinizing SCC than that in basaloid SCC(P<0.05). These findings suggested that MMP-2 and MMP-9, HER2/neu and MMP-9, MMP-2 and p53 had a coordinate function in aggression of tumor; that MMP-2 had a more important function than MMP-9 in tumor invasion and metastasis; and that HER2/neu might serve as a biomarker for poor prognosis in HNSCC.     

Notch signalling controls pancreatic cell differentiation.

The pancreas contains both exocrine and endocrine cells, but the molecular mechanisms controlling the differentiation of these cell types are largely unknown. Despite their endodermal origin, pancreatic endocrine cells share several molecular characteristics with neurons, and, like neurons in the central nervous system, differentiating endocrine cells in the pancreas appear in a scattered fashion within a field of progenitor cells. This indicates that they may be generated by lateral specification through Notch signalling. Here, to test this idea, we analysed pancreas development in mice genetically altered at several steps in the Notch signalling pathway. Mice deficient for Delta-like gene 1 (Dll1) or the intracellular mediator RBP-Jkappa showed accelerated differentiation of pancreatic endocrine cells. A similar phenotype was observed in mice over-expressing neurogenin 3 (ngn 3) or the intracellular form of Notch3 (a repressor of Notch signalling). These data provide evidence that ngn3 acts as proendocrine gene and that Notch signalling is critical for the decision between the endocrine and progenitor/exocrine fates in the developing pancreas.