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Imaoka T.,Research Center for Radiation Protection | Imaoka T.,Japan National Institute of Radiological Sciences | Okutani T.,Research Center for Radiation Protection | Okutani T.,Chiba University | And 8 more authors.
Anticancer Research | Year: 2014

Background/Aim: NOTCH-regulated ankyrin repeat protein (NRARP) has been implicated in crosstalk between NOTCH and wingless-type mouse mammary tumor virus integration site (WNT) signals during development. Our study aimed to clarify its role in breast cancer cells. Materials and Methods: Public microarray data were used to analyze gene expression in human and rat breast cancer. A short interfering RNA was introduced into MCF7 and T47D human breast cancer cells for NRARP silencing. Gene expression was analyzed by quantitative polymerase chain reaction. Results: The NRARP transcript was commonly overexpressed in various rat mammary cancer models. In addition, a subset of human breast cancer also expressed high levels of NRARP transcript, which correlated positively with up-regulation of cell proliferation-related genes. Silencing of NRARP suppressed the growth of MCF7 and T47D cells and lowered the expression of cell cycle-related genes in MCF7 cells. Conclusion: NRARP may stimulate cell proliferation in human breast cancer.

Moriyama A.,Tokyo Institute of Technology | Inohaya K.,Tokyo Institute of Technology | Maruyama K.,Research Center for Radiation Protection | Kudo A.,Tokyo Institute of Technology
Developmental Biology | Year: 2010

Vertebrate hematopoiesis is characterized by two evolutionally conserved phases of development, i.e., primitive hematopoiesis, which is a transient phenomenon in the early embryo, and definitive hematopoiesis, which takes place in the later stages. Beni fuji (bef) was originally isolated as a medaka mutant that has an apparently reduced number of erythrocytes in its peripheral blood. Positional cloning revealed that the bef mutant has a nonsense mutation in the c-myb gene. Previous studies have shown that c-myb is essential for definitive hematopoiesis, and c-myb is now widely used as a marker gene for the onset of definitive hematopoiesis. To analyze the phenotypes of the bef mutant, we performed whole-mount in situ hybridization with gene markers of hematopoietic cells. The bef embryos showed decreased expression of α-globin and l-plastin, and a complete loss of mpo1 and rag1 expression, suggesting that the bef embryos had defects not only in erythrocytes but also in other myeloid cells, which indicates that their definitive hematopoiesis was aberrant. Interestingly, we observed a diminution in the number of primitive erythrocytes and a delay in the emergence of primitive macrophages in the bef embryos. These results suggest that c-myb also functions in the primitive hematopoiesis, potentially demonstrating a link between primitive and definitive hematopoiesis. © 2010 Elsevier Inc.

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