Structure-Activity Relationship of SPOP Inhibitors against Kidney Cancer

Area of Science:

• Oncology
• Molecular Biology
• Medicinal Chemistry

Background:

• Speckle-type POZ protein (SPOP) overexpression and cytoplasmic mislocalization are hallmarks of clear-cell renal cell carcinoma (ccRCC), driving kidney tumorigenesis.
• Previous research identified compound 6b as an inhibitor of the oncogenic SPOP-signaling pathway by blocking SPOP-mediated protein interactions.

Purpose of the Study:

• To establish a structure-activity relationship for SPOP inhibitors based on compound 6b.
• To evaluate the efficacy of novel 6b analogues, specifically compound 6lc, in suppressing ccRCC progression.

Main Methods:

• Synthesis and structure-activity relationship analysis of 6b analogues.
• In vitro binding assays to confirm 6lc interaction with SPOP protein.
• Cell-based assays in ccRCC cell lines to assess viability, colony formation, and protein level changes (PTEN, DUSP7, p-AKT, p-ERK) upon 6lc treatment.
• Western blotting and ubiquitination assays to analyze PTEN pathway modulation.

Main Results:

• Compound 6lc demonstrated superior suppression of ccRCC cell viability and colony formation compared to 6b.
• 6lc directly binds to SPOP protein in vitro.
• 6lc treatment disrupted the interaction between SPOP and PTEN in HEK293T cells.
• In ccRCC cells, 6lc induced decreased PTEN ubiquitination, increased PTEN and DUSP7 levels, and reduced phosphorylated AKT and ERK in a dose-dependent manner.

Conclusions:

• Compound 6lc is a potent SPOP inhibitor with significant anti-ccRCC activity.
• 6lc effectively targets the SPOP-PTEN axis, offering a promising therapeutic strategy against kidney tumorigenesis.