Textural analysis of nuclear mitotic apparatus antigen (NuMA) spatial distribution in interphase nuclei from human
N Rafki-Beljebbar1, F Liautaud-Roger, D Ploton
1Unité MéDIAN, EA2063, IFR 53, Faculté de Pharmacie, Université de Reims, France.
Abstract:
In tumour cell lines, the resistance of cancer cells to a variety of structurally unrelated chemotherapeutic drugs is termed multidrug-resistance or MDR. We reported previously [6] that MDR leukemic cells displayed nuclear texture changes, as assessed by image cytometry. The nature of these changes remained uncertain but they could be associated with alterations of the nuclear matrix which could serve an important role in DNA organization and chromatin structure. Therefore, we have compared the textural features observed in G0/G1 nuclei from human leukemic CEM cells and their MDR variant CEM-VLB, after staining of either DNA by Feulgen method or nuclear matrix by immunodetection of NuMA antigen on DNase treated samples. Chromatin or NuMA distributions within the nucleus were evaluated by image cytometry. Changes in textural parameters indicate that modifications of NuMA distribution observed in MDR cells are parallel to those observed at the whole chromatin level (i.e., a more decondensed and coarse texture with increase of Energy and Long-run sections and decrease of Contrast and Short-run sections). Moreover, Optical Densities measurements indicate that MDR cells seem to contain less NuMA, a datum confirmed by immunoblotting of nuclear proteins. In conclusion, chromatin changes observed by image cytometry in drug-resistant human leukemic CEM cells appear associated with modifications of the nuclear matrix structure.
Insights
Multidrug-resistance (MDR) in cancer cells is linked to changes in nuclear texture and chromatin structure. These alterations in drug-resistant leukemic cells are associated with modifications in the nuclear matrix.
Area of Science:
- Cell Biology
- Cancer Research
- Biophysics
Background:
- Multidrug-resistance (MDR) is a major challenge in cancer chemotherapy, characterized by cancer cell resistance to various drugs.
- Previous studies indicated nuclear texture changes in MDR leukemic cells, suggesting potential alterations in nuclear organization.
Purpose of the Study:
- To investigate the association between nuclear matrix modifications and chromatin structure changes in drug-resistant human leukemic cells.
- To compare textural features of chromatin and nuclear matrix in sensitive and MDR leukemic cell lines.
Main Methods:
- Utilized image cytometry to analyze nuclear texture of human leukemic CEM cells and their MDR variant CEM-VLB.
- Employed Feulgen staining for DNA and immunodetection of NuMA antigen for nuclear matrix analysis.
- Performed Optical Densities measurements and immunoblotting to quantify NuMA levels.
Main Results:
- MDR cells exhibited altered chromatin texture, characterized by decondensation and coarseness, with increased Energy and Long-run sections and decreased Contrast and Short-run sections.
- Nuclear matrix (NuMA) distribution changes in MDR cells paralleled chromatin alterations.
- MDR cells showed reduced NuMA content compared to sensitive cells.
Conclusions:
- Chromatin changes observed in drug-resistant leukemic cells are linked to modifications in nuclear matrix structure.
- Nuclear matrix alterations may play a role in the development of multidrug-resistance in cancer cells.
