PSPC1 Inhibition Synergizes with Poly(ADP-ribose) Polymerase Inhibitors in a Preclinical Model of BRCA-Mutated Breast/Ovarian Cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors are effective against BRCA1/2-mutated cancers through synthetic lethality. Unfortunately, most cases ultimately develop acquired resistance. Therefore, enhancing PARP inhibitor sensitivity and preventing resistance in those cells are an unmet clinical need. Here, we investigated the ability of paraspeckle component 1 (PSPC1), as an additional synthetic lethal partner with BRCA1/2, to enhance olaparib sensitivity in preclinical models of BRCA1/2-mutated breast and ovarian cancers. In vitro, the combined olaparib and PSPC1 small interfering RNA (siRNA) exhibited synergistic anti-proliferative activity in BRCA1/2-mutated breast and ovarian cancer cells. The combination therapy also demonstrated synergistic tumor inhibition in a xenograft mouse model. Mechanistically, olaparib monotherapy increased the expressions of p-ATM and DNA-PKcs, suggesting the activation of a DNA repair pathway, whereas combining PSPC1 siRNA with olaparib decreased the expressions of p-ATM and DNA-PKcs again. As such, the combination increased the formation of γH2AX foci, indicating stronger DNA double-strand breaks. Subsequently, these DNA-damaged cells escaped G2/M checkpoint activation, as indicated by the suppression of p-cdc25C (Ser216) and p-cdc2 (Tyr15) after combination treatment. Finally, these cells entered mitosis, which induced increased apoptosis. Thus, this proves that PSPC1 inhibition enhances olaparib sensitivity by targeting DNA damage response in our preclinical model. The combination of olaparib and PSPC1 inhibition merits further clinical investigation to enhance PARP inhibitor efficacy.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:24

Enthalten in:

International journal of molecular sciences - 24(2023), 23 vom: 03. Dez.

Sprache:

Englisch

Beteiligte Personen:

Ghosh, Mithun [VerfasserIn]
Kang, Min Sil [VerfasserIn]
Katuwal, Nar Bahadur [VerfasserIn]
Hong, Sa Deok [VerfasserIn]
Jeong, Yeong Gyu [VerfasserIn]
Park, Seong Min [VerfasserIn]
Kim, Seul-Gi [VerfasserIn]
Moon, Yong Wha [VerfasserIn]

Links:

Volltext

Themen:

Antineoplastic Agents
BRCA1 Protein
BRCA2 Protein
DNA double-strand break
Journal Article
Olaparib
PARP inhibitor
PSPC1
PSPC1 protein, human
Poly(ADP-ribose) Polymerase Inhibitors
RNA, Small Interfering
RNA-Binding Proteins
Sensitivity
WOH1JD9AR8

Anmerkungen:

Date Completed 28.12.2023

Date Revised 28.12.2023

published: Electronic

Citation Status MEDLINE

doi:

10.3390/ijms242317086

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM365602264