NuMA Overexpression in Epithelial Ovarian Cancer

Highly aneuploid tumours are common in epithelial ovarian cancers (EOC). We investigated whether NuMA expression was associated with this phenomenon

Analysis of NuMA expression in EOC.

<p>A. Statistical analysis of the large ovarian cancer TMA showing NuMA expression increases with disease stage in the mucinous subtype. B. NuMA expression is associated with lymph node involvement (T3cN1MO) (all subtypes). C. NuMA expression is associated with patient age (all subtypes). D. High levels of NuMA decrease with tumour grade in the serous subtype. E. High NuMA levels are associated with stage 4 disease in serous EOCs. F. High NuMA levels increase with tumour grade in mucinous EOCs. G. High NuMA levels decrease with disease stage in endometrioid EOC. H. High NuMA levels decrease with tumour invasion status (T1 to T3) (all subtypes).</p

NuMA expression in ovarian cancer cell lines, primary cultures and tissue.

<p>A. Affymetrix data showing NuMA over-expression in 6 ovarian cell lines (JAMA-2, IOVE (additional immortalized ovarian epithelial cell line), SKOV-3, TR175, OVCA-433 (in addition) and 1847 (all grey bars, designated CL), 38 samples of primary cells cultured from ascitic fluid (black bars, designated – A, including some samples with consecutive collections or passages) and 4 primary cultures established from tumour tissue (designated –T1 to – T4). A1, A2 and A4 are tumour tissue (T1, T2, T4) associated ascites samples. Intensity values obtained for the samples were normalised to an internal control (normal epithelial ovarian tissue (N)) and gene expression levels are shown as the ratio of intensity levels/control intensity level as a log10 value. B. NuMA levels in cell lysates. A representative example of a lysates analysed for NuMA expression by slot blot Black asterix indicates ovarian cell lines (1847, TR175, JAMA-2), brown asterix the neuroblastoma cell line SH-SY5Y, pink asterix the colon adenocarcinoma cell line SW480, blue asterix the cervical cancer cell line HeLa, and yellow asterix the breast cancer cell line MCF7. All other samples are lysates from ovarian primary cultures. C. Histogram comparing NuMA levels in ovarian cell lines, a primary cell line derived from a benign gynaecological disorder (1153-A1) and primary cultures after normalisation against α-tubulin. D. Section of normal (N) ovarian epithelial and stromal tissue and matched ovarian cancer (Ca) at x10 and x40 magnification after NuMA immunostaining. Arrows indicate epithelial cells. Low to medium levels of nuclear NuMA staining can be seen in the normal epithelial cells, with higher levels of nuclear NuMA staining in the ovarian cancer epithelial cells. E. Analysis of a small ovarian TMA shows that NuMA staining intensity increases with grade in ovarian tumour tissue.</p

NuMA expression assessed by immunofluorescence reveals that NuMA localises to the nucleus during interphase and to the spindle poles during mitosis in cells of ovarian cancer cell lines and primary ascites cultures and fluorescence intensities vary among the primary cultures.

<p>A. Examples of interphase nuclei with low (a-d) and high (e-h) NuMA levels, and mitotic spindles with low (i-l) and high (m-p) NuMA levels at spindle poles. Green – NuMA, red – α-tubulin, blue - DAPI. Scale bar  = 5 µm. B. Histogram comparing NuMA nuclear fluorescence staining intensities in four ovarian cell lines, one cell line established from a primary culture (GYNA0089) and 23 primary cultures derived from ascitic fluid. C. Histogram comparing NuMA staining intensities at spindle poles in the subset of cell lines and cultures where a sufficient number of mitotic cells were for analysis.</p

Mitotic and interphase defects in primary cultures.

<p>A. Mitotic defects observed at metaphase included (a) asymmetrical bipolar spindles (b) multiple spindle poles, (c) tripolar spindles, (d) bipolar spindles with multiple spindle poles (e) cells with misplaced and misaligned spindles (cell periphery outlined). B. Mitotic defects observed at anaphase included lagging chromosomes and anaphase bridging (a -c). C. Mitotic defects observed during telophase and cytokinesis included (a) abnormal spindles, (b) abnormal cytokinesis with micronuclei formation, (c), chromatid bridging and (d) formation of unevenly sized daughter cells. D. Examples of (a) binucleation, (b) multinucleation and (c) micronuclei in primary cultures. Green – NuMA, red – α-tubulin, blue – DAPI in all panels. Scale bar in A and B = 5 µm. Scale bar in C and D = 10 µm. E. Pie chart illustrating the overall frequency of mitotic defects observed in the primary cultures.</p

NuMA expression in primary cultures is associated with mitotic stage, mitotic defects and aneuploidy.

<p>Strong nuclear NuMA expression was associated with (A) the lowest proportion of telophase cells and (B) the highest proportion of cells with a diffuse metaphase plate. Strong NuMA spindle pole labelling was associated with high rates of (C) binucleation, (D) multinucleation, (E) a diffuse metaphase plate and (F) the lowest proportion of cells in cytokinesis. (G) Intermediate spindle pole staining was associated with the lowest proportion of cells exhibiting a cytokinesis defect. (H) FACS analysis revealed that only cells with high levels of NuMA were aneuploid.</p

NuMA expression in different ovarian tumour subtypes.

<p>Low and high NuMA staining patterns observed in cores from serous, mucinous, endometrial and clear cell carcinomas in a large scale ovarian TMA. Magnification x10.</p