Epithelial cell terminal differentiation

Hsu, S. et al. Green tea polyphenol-induced epithelial cell terminal differentiation is associated with coordinated expression of p57/KIP2 and caspase 14. J Pharmacol Exp Ther. 312, 884, 2005. 

At the corneal surface, two to four layers of polygonal, extremely flat, and terminally differentiated superficial cells can be found. The cell diameters are 40-60 /xm with about 2-6 /xm thickness. The corneal surface is populated with microvilli and microplicae, resulting in surface area enlargement. These structures are associated with the tear film. Superficial corneal epithelial cells are... 

Thiazolidinedione PPARy agonists have also been reported to induce terminal differentiation of malignant breast epithelial cells (105), which suggests that PPARy activation could be used in the treatment of breast cancer. Recently, it was also shown that ligands for PPARy are inhibitors of angiogenesis (106) however, the dose-response characteristics in this study do not agree with those for receptor binding and activation (9). 

Epithelial cells in the intestine, as in many other epithelia such as the skin, renew themselves continually, by shedding terminally differentiated cells from the surface and replacing them with new cells, derived from the stem cells in the deeper basal layers (Fig. 16.2). But, for malignant transformation, it is not enough that stem cells just divide more rapidly, because as stem cells divide more rapidly, more terminally differentiated cells will be produced too. This would merely increase cell turnover. Immortal cancer cells are formed only when this balance is upset, either when the stem cell itself is transformed and fails to produce a cell which will differentiate and eventually die, or when the cell originating from the stem cell is mutated and fails to differentiate normally and instead divides indefinitely, without dying. 

Such an image is simultaneously diagnostic of epithelial and neuroendocrine differentiation in a small-cell cutaneous neoplasm, even if such markers as chromogranin, synaptophysin, and CD56 are absent in the tumor. Keratin assumes particular importance in making the distinction between PCNC and lymphoma because both of those tumor types share the potential for expression of PAX-5 and terminal deoxynucleotidyl transferase. " ... 

Figure 4 Triantennary iV-glycans involved in germ cell and Sertoli cell interaction in the mouse testis. Spermatogenesis takes place in the tubal structure called seminiferous tube in the testis. Inside of seminiferous tube is lined by Sertoli cells, the tail epithelial cells. When germ stem cells at the base of Sertoli cells differentiate to spermatocytes, the cells move upward interacting with Sertoli cells. The MX gene knockout mouse revealed that fucosylated GlcNAc-terminated triantennary A-glycan (insert) plays an important role in germ cell adhesion to Sertoli cells (59).

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