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STAT3 and PKC Differentially Regulate Telomerase Activity During Megakaryocytic Differentiation of K562 Cells

Mayuka Nakatake, Yasutaka Kakiuchi, Narie Sasaki, Kimiko Murakami-Murofushi and Osamu Yamada

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Telomerase is active in immature somatic cells, but not in differentiated cells. However, the regulation during cell differentiation is not well understood. In this study, a human chronic myelogenous leukemia cell line (K562) was induced to differentiate into megakaryocytes by TPA, and erythroid by STI571. A human acute myeloblastic leukemia cell line (HL60) was also induced to differentiate into monocytes by TPA and VD3, and granulocyte by ATRA. TPA induced transient increase of telomerase activity (mainly nuclear fraction) during megakaryocytic differentiation, while the expression of hTERT decreased gradually throughout the same period. Pretreatment with PKC inhibitors inhibited the megakaryocytic differentiation, transient increase of telomerase activity, while recombinant PKC increased telomerase activity. ChIP assay resulted STAT3 and STAT5 dissociated from the hTERT promoter, indicating that STAT3 and STAT5 are one of the transcriptional regulators. These results suggest that telomerase activity is regulated by two mechanisms during megakaryocytic differentiation.

Authors

Mayuka Nakatake

Ochanomizu University, Tokyo, Japan

Yasutaka Kakiuchi

Ochanomizu University, Tokyo, Japan

Narie Sasaki

Ochanomizu University, Tokyo, Japan

Kimiko Murakami-Murofushi

Ochanomizu University, Tokyo, Japan

Osamu Yamada

Tokyo Women's Medical University, Tokyo, Japan

Purchase article for $19

Subscribe to this journal for $129/year