| 1. |
- Ekberg, Jenny, et al.
(författare)
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Regulation of the cyclin A1 protein is associated with its differential subcellular localization in hematopoietic and leukemic cells
- 2004
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Ingår i: Oncogene. - : Nature Publishing Group. - 0950-9232 .- 1476-5594. ; 23:56, s. 9082-9089
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Tidskriftsartikel (refereegranskat)abstract
- An important role of the cell cycle regulatory protein cyclin A1 in the development of acute myeloid leukemia (AML) was previously demonstrated in a transgenic mouse model. We have now turned our attention to study specific aspects of the activity and subcellular distribution of cyclin A1 using bone marrow samples from normal donors and patients with AML, as well as leukemic cell lines. We show that the localization of cyclin A1 in normal hematopoietic cells is nuclear, whereas in leukemic cells from AML patients and cell lines, it is predominantly cytoplasmic. In leukemic cell lines treated with all-trans retinoic acid (ATRA), cyclin A1 localized to the nucleus. Further, there was a direct interaction between cyclin A1 and cyclin-dependent kinase 1, as well as a major ATRA receptor, RARalpha, in ATRA-treated cells but not in untreated leukemic cells. Our results indicate that the altered intracellular distribution of cyclin A1 in leukemic cells correlates with the status of the leukemic phenotype.
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| 2. |
- Liao, Ching, et al.
(författare)
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Elevated levels and distinct patterns of expression of A-type cyclins and their associated cyclin-dependent kinases in male germ cell tumors
- 2004
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 108:5, s. 654-664
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Tidskriftsartikel (refereegranskat)abstract
- Aberrant expression of several key regulators controlling the G1/S phase of the cell cycle has been implicated in human male germ cell tumorigenesis. Given the critical role of cyclin A2 at both the G1/S and G2/M transitions and the essential role for cyclin A1 in male germ cell development, our present study focused on the involvement of the A-type cyclins in the transformation and progression of male germ cell tumors (GCTs). The expression of the A-type cyclins and their catalytic partners Cdk1 and Cdk2 was examined in all types and stages of human male GCTs, including carcinoma in situ(CIS), seminoma and non-seminoma GCTs, along with normal testis samples. Elevated levels of cyclin A2, Cdk1 and Cdk2 were detected in the majority of GCTs and were correlated with the invasiveness of the tumors (p < 0.05). Cyclin A1 expression was virtually undetectable in CIS and seminoma, but was aberrantly expressed in all non-seminomatous GCTs. Cyclin A2 expression was strongly correlated with that of its catalytic partners Cdk1 and Cdk2 in all types of testicular tumors examined (p < 0.05), whereas a strong correlation between cyclin A1 and Cdk1 or Cdk2 was only seen in non-seminomatous GCTs (p < 0.05). Histone kinase activities of cyclin A1/Cdks and cyclin A2/Cdks were found to be elevated in tumors. Our data suggest that aberrant expression of A-type cyclins and their Cdks is a significant factor in male germ cell tumorigenesis. The abundant ectopic expression of cyclin A1 in non-seminomatous GCTs and its absence in CIS and seminomas is likely linked to the tumor transformation and progression and may be relevant to clinical prognosis.
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