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Updated: Apr 4, 2026

Flow Cytometric Analysis of Apoptotic Biomarkers in Actinomycin D-Treated SiHa Cervical Cancer Cells
Published on: August 26, 2021
The interactions between SATB1 and F-actin are important for mechanisms of active cell death
Dariusz Grzanka1, Anna E Kowalczyk, Magdalena Izdebska
1Department and Clinic of Dermatology, Sexually Transmitted Diseases and Immunodermatology, Nicolaus Copernicus University in Torun, Collegium Medicum in Bydgoszcz, Poland. d_gr@me.com.
Introduction:
The direct involvement of nuclear actin filaments in gene transcription and remodeling of chromatin is still debatable. However, nuclear localization of F-actin and its interactions with other nuclear matrix proteins have been reported. The aim of the study was to estimate the interactions between nuclear F-actin and one of the matrix proteins, special AT-rich sequence-binding protein 1 (SATB1), during active cell death induced in vitro by geldanamycin (GA).
Material And Methods:
The expression of SATB1 was modified by the transfection of non-aggressive breast cancer MCF-7 cells with siRNA against SATB1 or expression plasmid with cloned cDNA of SATB1. The amount and localization of F-actin were altered by changes of cofilin-1 (CFL1) expression in MCF-7 cells. The association between SATB1 and F-actin during GA-induced cell death was analyzed using confocal and transmission electron microscopy.
Results:
Our studies revealed the colocalization between nuclear F-actin and SATB1 protein, during GA-induced death of breast cancer MCF-7 cells. The colocalization was enhanced in cells with overexpressed SATB1 and cofilin-1. At the ultrastructural level the SATB1 and F-actin complexes were seen at the border of condensed and decondensed chromatin. The presence of SATB1/F-actin molecular complexes was confirmed by magnetic separation of F-actin and interacting proteins.
Conclusion:
We suggest that the molecular interactions between SATB1 and F-actin are necessary for active cell death to occur.
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