Cell differentiation and carcinogenesis: a critical review

The NF-κB p65/miR-23a-27a-24 cluster is a target for leukemia treatment

p65 is a transcription factor that is involved in many physiological and pathologic processes. Here we report that p65 strongly binds to the miR-23a-27a-24 cluster promoter to up-regulate its expression. As bone marrow-derived cells differentiate into red blood cells in vitro, p65/miR-23a-27a-24 cluster expression increases sharply and then declines before the appearance of red blood cells, suggesting that this cluster is negatively related to erythroid terminal differentiation. Bioinformatic and molecular biology experiments confirmed that the miR-23a-27a-24 cluster inhibited the expression of the erythroid proteome and contributed to erythroleukemia progression. In addition, high level of the p65/miR-23a-27a-24 cluster was found in APL and AML cell lines and in nucleated peripheral blood cells from leukemia patients. Furthermore, anti-leukemia drugs significantly inhibited the expression of the p65/miR-23a-27a-24 cluster in leukemia cells. Administration of the p65 inhibitor parthenolide significantly improved hematology and myelogram indices while prolonging the life span of erythroleukemia mice. Meanwhile, stable overexpression of these three miRNAs in mouse erythroleukemia cells enhanced cell malignancy. Our findings thus connect a novel regulation pathway of the p65/miR-23a-27a-24 cluster with the erythroid proteome and provide an applicable approach for treating leukemia.

Differentiation of regenerating pancreatic cells into hepatocyte-like cells

Differentiation is the process by which multicellular organisms achieve the specialized functions necessary for adaptation and survival. An in vivo model in the Syrian golden hamster is described in which regenerating pancreatic cells are converted into hepatocyte-like cells, as evidenced by the presence of albumin, peroxisomes, and a variety of morphological markers. These cells are stable after the conversion is triggered by a single dose of the carcinogen N-nitrosobis(2-oxopropyl)amine administered during the S phase in regenerating pancreatic cells. This suggests that, given the proper stimulus, regenerating cells in adult pancreas can be redirected into a totally different pathway of differentiation.