RESUMO
BACKGROUND: High-grade serous ovarian cancer (HGSOC) is the most common and lethal ovarian cancer histotype. Chromosome instability (CIN, an increased rate of chromosome gains and losses) is believed to play a fundamental role in the development and evolution of HGSOC. Importantly, overexpression of Cyclin E1 protein induces CIN, and genomic amplification of CCNE1 contributes to HGSOC pathogenesis in ~20% of patients. Cyclin E1 levels are normally regulated in a cell cycle-dependent manner by the SCF (SKP1-CUL1-FBOX) complex, an E3 ubiquitin ligase that includes the proteins SKP1 and CUL1. Conceptually, diminished SKP1 or CUL1 expression is predicted to underlie increases in Cyclin E1 levels and induce CIN. METHODS: This study employs fallopian tube secretory epithelial cell models to evaluate the impact diminished SKP1 or CUL1 expression has on Cyclin E1 and CIN in both short-term (siRNA) and long-term (CRISPR/Cas9) studies. RESULTS: Single-cell quantitative imaging microscopy approaches revealed changes in CIN-associated phenotypes and chromosome numbers and increased Cyclin E1 in response to diminished SKP1 or CUL1 expression. CONCLUSIONS: These data identify SKP1 and CUL1 as novel CIN genes in HGSOC precursor cells that may drive early aetiological events contributing to HGSOC development.
Assuntos
Instabilidade Cromossômica/genética , Cistadenocarcinoma Seroso , Células-Tronco Neoplásicas/metabolismo , Neoplasias Ovarianas , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Proteínas Culina/genética , Proteínas Culina/metabolismo , Ciclina E/genética , Ciclina E/metabolismo , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/patologia , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Gradação de Tumores , Células-Tronco Neoplásicas/patologia , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Proteínas Quinases Associadas a Fase S/genética , Proteínas Quinases Associadas a Fase S/metabolismo , Células Tumorais CultivadasRESUMO
The majority of ovarian cancers (OCs) arise from the ovarian surface epithelium (OSE). Proliferation of the OSE can be regulated by a number of autocrine and paracrine factors, including transforming growth factor beta (TGFbeta). Defects in the TGFbeta signaling pathway have been implicated in a number of cancers, including ovarian. We previously found that the TGFbeta signaling pathway is intact and functional in primary human OC cells, and that these cells stop growing in response to TGFbeta. Ovarian cancer cells in vivo are exposed to TGFbeta, yet continue to proliferate, therefore, mechanisms must exist to inhibit TGFbeta signaling contributing to uncontrolled cellular proliferation. Numerous signaling pathways converge with the TGFbeta pathway to modulate its effects, including signaling induced by epidermal growth factor (EGF). We hypothesized that EGF can modulate TGFbeta signaling and contribute to uncontrolled cellular proliferation of OC cells. Our results show that EGF abrogates the antiproliferative effect of TGFbeta. EGF does not modulate TGFbeta signaling by inhibiting receptor-activated Smad (R-Smad) phosphorylation or nuclear translocation. Rather, EGF decreases TGFbeta-induced mRNA expression of the cell cycle regulator, p15(INK4B), contributing to decreased sensitivity of OC cells to the antiproliferative effect of TGFbeta.
Assuntos
Fator de Crescimento Epidérmico/metabolismo , Neoplasias Ovarianas/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Proteínas Supressoras de Tumor , Transporte Ativo do Núcleo Celular , Northern Blotting , Western Blotting , Proteínas de Ciclo Celular/metabolismo , Divisão Celular , Núcleo Celular/metabolismo , Inibidor de Quinase Dependente de Ciclina p15 , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Microscopia de Fluorescência , Fosforilação , RNA Mensageiro/metabolismo , Transdução de Sinais , Proteína Smad2 , Proteína Smad3 , Fatores de Tempo , Transativadores/metabolismo , Células Tumorais Cultivadas , Regulação para CimaRESUMO
TGFß superfamily signalling participates in normal and pathophysiologic cellular processes. Despite several reports demonstrating active TGFß superfamily signalling pathways in OvCa cell lines and primary cultures, few studies examine their functional outcome. Herein we show that primary human ovarian cancer cells possess intact autocrine BMP, TGFß and activin signalling. Blocking autocrine signalling resulted in differential cellular responses affecting cellular morphology, motility and proliferation. Additionally, BMP4-induced alterations in morphology and motility are dependent on Smad signalling. These results suggest that a balance between BMP and TGFß/activin signalling may be altered to favour BMP signalling during ovarian cancer metastatic progression.