Fig. 4.
PAX8 is essential for ovarian cancer cell proliferation and survival. (A) PAX8 is the top-ranked differentially expressed gene between ovarian and nonovarian cancer cell lines. Arrow indicates PAX8. (B) SNP array colorgrams depict genomic amplification of PAX8 in primary high-grade serous ovarian cancers (1). Regions of genomic amplification and deletion are denoted in red and blue, respectively. SNP array profiles derived from primary ovarian tumors were sorted based on the degree of amplification of each gene. Black vertical lines denote the boundaries of the PAX8 gene. (C) Boxplot showing significant difference in the degree of depletion of a PAX8-specific shRNA in 63 cell lines with low levels of PAX8 compared with 20 lines with high levels of PAX8 (P = 2.14 × 10−8, t test). Cell lines were divided into high- and low-expressing groups. The red line indicates the median value for each group, boxes represent the 25th to 75th percentile of the data, and whiskers extend to the most extreme values of the group that are not considered outliers. Ovarian cancer cell lines are plotted with red circles; cell lines from all other lineages are plotted with green circles. (D Upper) Effects of PAX8 suppression on proliferation in eight ovarian cancer cell lines; dotted line indicates 50% relative proliferation. (Lower) Immunoblot of PAX8 in a panel of eight ovarian cancer cell lines and in immortalized IOSE-T80 cells. Cell lines with amplification of 2q13 (log2 copy number ratio > 0.3) are marked in red. * denotes nonspecific band. (E Upper) Effects of PAX8 suppression on proliferation of cell lines from indicated cancer types. (Lower) Immunoblot of PAX8. Error bars indicate SD of six replicate measurements. (F) Immunoblot of poly(ADP-ribose) polymerase after PAX8 suppression in two 2q13-amplified cell lines. * denotes nonspecific band.