NY-ESO-1 facilitates anoikis resistance and tumor metastasis by hijacking deubiquitinase OTUB1 to stabilize PP1α.

Abstract

Anoikis resistance, an essential prerequisite for tumor metastasis, is now recognized as a promising target in the fight against tumor progression. However, the detailed mechanisms of anoikis resistance are not fully understood, and drugs targeting anoikis resistance are not currently available. Here we report that NY-ESO-1, a well-known cancer-testis antigen, is linked to a poor prognosis in tumor patients and that it is crucial for anoikis resistance and tumor metastasis. Overexpression of NY-ESO-1 in cancer cells enhanced ERK1/2 activation, which in turn promoted resistance to anoikis, increased colony formation in soft agar, and facilitated lung metastasis in mice. Conversely, NY-ESO-1 knockdown significantly reduced ERK1/2 activity, leading to enhanced anoikis, diminished colony formation, and impaired metastatic potential. Mechanistically, NY-ESO-1 acts as a scaffold protein to recruit the deubiquitinase OTUB1 to PP1α, forming a ternary complex that prevents PP1α from being ubiquitinated. The OTUB1's deubiquitinase activity, not its ability to suppress E2 enzymes, is necessary for reducing polyubiquitination and improving PP1α stability. Finally, accumulated PP1α proteins significantly activate downstream ERK1/2. Blockade of ERK1/2 or knocking down PP1α antagonized NY-ESO-1-mediated anoikis resistance. These results not only reveal a previously unrecognized mode for deubiquitinase substrate expansion but also highlight the function of NY-ESO-1 in anoikis resistance and suggest NY-ESO-1 as a novel attractive target for preventing tumor metastasis.