SPOP attenuates migration and invasion of choriocarcinoma cells by promoting DHX9 degradation

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Speckle-type POZ protein (SPOP) has a dual role in cancer, acting as a tumor suppressor or promoter.
• Its specific function and mechanisms in choriocarcinoma remain largely unexplored.

Purpose of the Study:

• To elucidate the biological functions of SPOP in choriocarcinoma.
• To investigate the molecular mechanisms underlying SPOP's role in choriocarcinoma progression.

Main Methods:

• Analysis of SPOP and DHX9 expression in patient tissues and cell lines.
• Lentivirus-mediated induction or depletion of SPOP to assess effects on cell migration and invasion.
• Co-immunoprecipitation and ubiquitination assays to determine the SPOP-DHX9 interaction and degradation pathway.

Main Results:

• Decreased SPOP expression and increased Nuclear DNA helicase II and RNA helicase A (DHX9) expression were observed in choriocarcinoma.
• SPOP suppressed choriocarcinoma cell migration and invasion, while SPOP depletion promoted these processes.
• SPOP directly binds to DHX9, inducing its ubiquitination and degradation via a specific binding motif.
• Knockdown of DHX9 partially reversed the pro-migratory and invasive effects caused by SPOP depletion.

Conclusions:

• SPOP acts as a tumor suppressor in choriocarcinoma by promoting DHX9 ubiquitination and degradation.
• The SPOP-DHX9 interaction is crucial for regulating choriocarcinoma cell motility.
• Targeting the SPOP-DHX9 interaction presents a potential therapeutic strategy for choriocarcinoma.