Fig. 1: OTUD1 is identified to be associated with OSCS maintenance and its high expression positively correlate with histological high-grade ovarian serous cancers.

a A multiomic integration approach was developed to screen the key factor controlling self-renewal and maintenance of OCSC. SKOV3 floating spheres and the derived differentiated cells were subjected to RNA-seq analysis, which is sorted by \(-{\log }_{10}\,{P\; {{{{\rm{Value}}}}}}\). The obtained differentially expressed genes were further screened based on the gene dataset of susceptibility loci for ovarian cancer and their negatively correlation with tumor prognosis. SDC Sphere Differentiated Cells. FS Floating Sphere. b Kaplan–Meier survival curves revealed a negative correlation between OTUD1 expression level and progression-free survival (PFS) in individuals with serous ovarian cancer (https://kmplot.com/analysis/). n = 535 patients with serous ovarian cancer. c The protein level of OTUD1 were measured in SKOV3 floating spheres and the derived differentiated cells. SDC Sphere Differentiated Cells. FS Floating Sphere. d Immunohistochemistry analysis of OTUD1 protein abundance in ovarian serous cancer tissue microarray; representative images of indicated pathological grade are shown (Scale bar, 20 μm). LGSOC samples, n = 4; HGSOC samples, n = 54. HGSOC, High grade serous ovarian carcinoma. LGSOC Low grade serous ovarian carcinoma. Representative images (e) and statistical analysis (f) demonstrating the effects of OTUD1 knockout on floating sphere-forming capacity in SKOV3 and OVCAR8 cell lines (n = 3). Scale bar, 50 μm. g Flow cytometry analysis of CD44⁺ and CD133⁺ CSCs in SKOV3 OTUD1 depleted cell line. Numbers in the charts indicate the percentages of corresponding subpopulations (n = 3). Tumor images (h) and volumes (i) in mice injected with negative control and OTUD1 knockout SKOV3 cells (n = 6 mice per group). Tumor sizes were monitored and the protein level of xenografts were analyzed by western blot (j). P values are calculated using two-tailed unpaired Student’s t test (d), one-way ANOVA (f, g) and two-way ANOVA (i). n.s. not significant. Representative of n = 3 independent experiments (c, e, g). Source data are provided as a Source Data file.