USP10 is associated with TUBA1B protein stability, PI3K/AKT phosphorylation changes, and progression of triple-negative breast cancer.

Abstract

Triple-negative breast cancer (TNBC) is clinically aggressive and has few actionable molecular targets. Tubulin alpha-1B chain (TUBA1B), an alpha-tubulin isoform, has been linked to breast cancer progression, but the post-translational regulation of its abundance in TNBC remains incompletely understood. We integrated paired TNBC tissues, breast-derived cell lines, subcutaneous xenografts, an experimental lung-colonization model, immunoprecipitation-mass spectrometry, co-immunoprecipitation, colocalization, cycloheximide chase, cellular ubiquitin-associated assays, proteasome inhibition, and bidirectional genetic rescue. TUBA1B was elevated in the examined TNBC tissues and cell lines, and its manipulation altered proliferation, clonogenicity, migration-associated behavior, invasion, xenograft growth, and experimental lung colonization. USP10 was selected from the TUBA1B-associated proteome for detailed study. Endogenous co-immunoprecipitation supported an intracellular association between USP10 and TUBA1B, whereas cycloheximide chase, a cellular HA-ubiquitin-associated readout, and formal USP10-status-by-MG132 interaction analyses were consistent with USP10-associated TUBA1B stability and proteasome-sensitive turnover. Bidirectional rescue showed that TUBA1B contributes to USP10-associated cellular phenotypes. Changes in USP10 and TUBA1B were accompanied by corresponding changes in PI3K/AKT phosphorylation. These findings support a functional USP10-TUBA1B protein-stability relationship in TNBC cells that is accompanied by PI3K/AKT phosphorylation changes; direct catalytic deubiquitination and pathway causality require further testing.