Cell Rep. 2023 Sep 19. pii: S2211-1247(23)01156-7. [Epub ahead of print]42(10): 113144
Pamoda Galhenage,
Yunlan Zhou,
Erica Perry,
Brenda Loc,
Kelly Fietz,
Sonia Iyer,
Ferenc Reinhardt,
Tiego Da Silva,
Vladimir Botchkarev,
Jie Chen,
Christopher P Crum,
Robert A Weinberg,
Shailja Pathania.
Clinical and molecular evidence indicates that high-grade serous ovarian cancer (HGSOC) primarily originates from the fallopian tube, not the ovarian surface. However, the reasons for this preference remain unclear. Our study highlights significant differences between fallopian tube epithelial (FTE) and ovarian surface epithelial (OSE) cells, providing the molecular basis for FTEs as site of origin of HGSOC. FTEs, unlike OSEs, exhibit heightened replication stress (RS), impaired repair of stalled forks, ineffective G2/M checkpoint, and increased tumorigenicity. BRCA1 heterozygosity exacerbates these defects, resulting in RS suppression haploinsufficiency and an aggressive tumor phenotype. Examination of human and mouse sections reveals buildup of the RS marker 53BP1 primarily in the fallopian tubes, particularly at the fimbrial ends. Furthermore, menopausal status influences RS levels. Our study provides a mechanistic rationale for FTE as the site of origin for HGSOC, investigates the impact of BRCA1 heterozygosity, and lays the groundwork for targeting early HGSOC drivers.
Keywords: BRCA1; CP: Cancer; Cell of origin; DNA damage checkpoints; DNA damage repair; High-grade serous ovarian cancer; fallopian tube; fimbrial ends; ovarian fat pad injection; replication stress; replication stress marker