Nuclear texture and chromatin structure in OV1/VCR human multidrug-resistant cell line.

Previous studies have demonstrated that multidrug-resistant leukemic cells displayed nuclear texture changes. In this work, the human ovarian carcinoma cell line IGROV1 and its multidrug-resistant variant OV1/VCR were studied. Cell smears of these cell populations were analysed by image cytometry. As compared to sensitive cells, OV1/VCR display a chromatin global decondensation as assessed by textural features analysis. In order to correlate this decondensation with alterations in chromatin structure, DNase I was used. OV1/VCR DNA displayed an increased DNase I sensitivity, suggesting an increased chromatin accessibility. Furthermore, OV1/VCR cells displayed an increased level in acetylated histone H4, a mechanism known to be associated with transcriptionally active chromatin and relaxed chromatin conformation.