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Analysis of hypoxia‐inducible factor‐1α accumulation and cell cycle in geldanamycin‐treated human cervical carcinoma cells by laser scanning cytometry
Author(s) -
Schwock Jörg,
Geddie William R.,
Hedley David W.
Publication year - 2005
Publication title -
cytometry part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.316
H-Index - 90
eISSN - 1552-4930
pISSN - 1552-4922
DOI - 10.1002/cyto.a.20192
Subject(s) - geldanamycin , biology , cell cycle , microbiology and biotechnology , cell culture , heat shock protein , mitosis , hsp90 , cell , biochemistry , genetics , gene
Background Tumor hypoxia has been linked to increased disease aggressiveness and poorer treatment outcomes, and the transcription factor hypoxia‐inducible factor‐1 (HIF‐1) has been identified as the key molecule mediating the cellular response to hypoxic microenvironments. The α‐subunit of this factor is accumulated under hypoxia and rapidly degraded during re‐oxygenation, rendering the reliable measurement of HIF‐1α a difficult task. Heat shock protein 90 (Hsp90) is an essential protein that controls the activity, turnover, and trafficking of a variety of other proteins including HIF‐1α and cell cycle regulators. Hsp90 inhibitors like geldanamycin therefore have the potential to target tumor‐cell survival by at least two mechanisms, compromising the accumulation of HIF‐1α and cell proliferation. Methods We describe here the simultaneous measurement of HIF‐1α and cell cycle parameters by laser scanning cytometry (LSC) after exposure of two different human cervical carcinoma cell lines to hypoxia and geldanamycin. Results Our analysis demonstrates that the cell lines react to hypoxia and drug treatment in a distinct way, with SiHa being more affected by low oxygen concentrations than is ME180, which was more sensitive to geldanamycin treatment. Both cell lines respond to geldanamycin with a G 2 /M‐phase arrest and a decrease in HIF‐1α accumulation. Cell death due to geldanamycin occurs in association with mitosis, presumably through mitotic catastrophe. Conclusion Our results indicate that LSC can significantly contribute to the evaluation of in vitro drug effects particularly with respect to tumor hypoxia and the measurement of HIF‐1α. © 2005 Wiley‐Liss, Inc.