Cezanne promoted autophagy through PIK3C3 stabilization and PIK3C2A transcription in lung adenocarcinoma.

Wang, Yadong; Li, Jiahao; Zheng, Haotian; Wang, Kai; Ren, Xiaoyang; Wang, Guanghui; Du, Jiajun

Osimertinib is a promising approved third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) for treating patients with lung adenocarcinoma (LUAD) harboring EGFR-activating mutations, however, almost all patients develop resistance to Osimertinib eventually limiting the long-term efficacy. Autophagy is a vital cellular recycling process promoting Osimertinib resistance. Identifying accurate and efficient autophagy-regulatory factors is of great significance in reducing Osimertinib resistance. This study identified Cezanne, a member of the ovarian tumor protease (OTU)-deubiquitinating family, as an autophagy regulator. Cezanne was highly expressed in Osimertinib-resistant cells, and Cezanne overexpression promoted Osimertinib resistance, while chloroquine (CQ), an autophagy inhibitor, reverted this process. In the Cezanne-overexpressing cells, autophagy was activated even in the absence of autophagy inducers rapamycin and Earle's Balanced Salt Solution (EBSS). Further study showed that Cezanne stabilized PIK3C3 by deubiquitinating K48-linked ubiquitination at Lysine 322. Surprisingly, as a compensatory mechanism of PI3P generation, PIK3C2A was shown to be upregulated by Cezanne by promoting its transcription in a POLR2A-dependent way. Based on these results, Cezanne also accelerates EGFR recycling which may explain the mechanism mediating Cezanne expression and Osimertinib resistance. In conclusion, this study establishes a new model connecting Cezanne, autophagy, and Osimertinib resistance, opening new avenues to explore the effect of Cezanne and autophagy in LUAD. Highlights: Cezanne contributed to Osimertinib resistance in LUAD. Cezanne stabilized PIK3C3 by deubiquitinating K48-linked ubiquitination on lys322 residue. Cezanne promoted PIK3C2A transcription in a POLR2A-dependent way. Cezanne activated autophagy to accelerate EGFR recycling.

CEZANNE, Paul, 1839-1906; EPIDERMAL growth factor receptors; AUTOPHAGY; PHYSIOLOGIC salines; PROTEIN-tyrosine kinase inhibitors

Cell Death Discovery, 2023, Vol 9, Issue 1, p1

2058-7716

Academic Journal

10.1038/s41420-023-01599-4