USP17 is required for trafficking and oncogenic signaling of mutant EGFR in NSCLC cells

Abstract

BackgroundThe deubiquitinase USP17 is overexpressed in NSCLC and has been shown to be required for the growth and motility of EGFR wild-type (WT) NSCLC cells. USP17 is also required for clathrin-mediated endocytosis of EGFR. Here, we examine the impact of USP17 depletion on the growth, as well as EGFR endocytosis and signaling, of EGFR mutant (MT) NSCLC cells. In particular, we examine NSCLC cells harboring an EGFR activating exon 19 deletion (HCC827), or both the L858R activating mutation and the T790M resistance gatekeeper mutation (H1975) which renders them resistant to EGFR tyrosine kinase inhibitors (TKIs).MethodsMTT, trypan blue and clonogenic assays, confocal microscopy, Western blotting and cell cycle analysis were performed.ResultsUSP17 depletion blocks the growth of EGFRMT NSCLC cells carrying either the EGFR exon 19 deletion, or L858R/T790M double mutation. In contrast to EGFRWT cells, USP17 depletion also triggers apoptosis of EGFRMT NSCLC cells. USP17 is required for clathrin-mediated endocytosis in these EGFRMT NSCLC cells, but it is not required for the internalization of the mutated EGFR receptors. Instead, USP17 depletion alters the localization of these receptors within the cell, and although it does not decrease basal EGFR activation, it potently reduces activation of Src, a key kinase in mutant EGFR-dependent tumorigenicity. Finally, we demonstrate that USP17 depletion can trigger apoptosis in EGFRWT NSCLC cells, when combined with the EGFR tyrosine kinase inhibitor (TKI) gefitinib.ConclusionsOur data reveals that USP17 facilitates trafficking and oncogenic signaling of mutant EGFR and indicates targeting USP17 could represent a viable therapeutic strategy in NSCLC tumours carrying either an EGFR activating mutation, or a resistance gatekeeper mutation.

Ubiquitin‑specific peptidase 17 promotes cisplatin resistance via PI3K/AKT activation in non‑small cell lung cancer

“…In the present study, it was found that cisplatin treatment upregulated USP17 expression in a dose-dependent manner. Moreover, increased cell proliferation was found in USP17-OE cells compared with that of control cells, which is consistent with previous studies (14)(15)(16)(17). Furthermore, it was demonstrated that the viability of USP17-OE cells was significantly higher than that of the control cells, when treated with cisplatin.…”

“…In addition, USP17 regulates the Ras pathway by altering the intracellular localization of Ras and other small GTPases, which are crucial regulators of cellular proliferation and migration (10). USP17 is required for the trafficking and oncogenic signaling of mutant epidermal growth factor receptor (EGFR) in NSCLC cells (15). These studies verified the role of USP17 in promoting tumor growth and metastasis.…”

“…The USP family is one of the five subfamilies of DUB enzymes, which cleave polyubiquitin chains from proteins, a number of studies have reported that USP17 has oncogenic characteristics. Firstly, it has been shown that high levels of USP17 in lung, colon, esophageal and cervical tumor samples promoted G1/S transition and cellular proliferation (14)(15)(16)(17). Additionally, it was demonstrated that USP17 was expressed highly in NSCLC tissues, and patients with high levels of USP17 exhibited lower survival rates (16,17).…”

“…Ubiquitin-specific protease 17 (USP17), a DUB, is involved in the regulation of inflammation (9) and cell motility (10), the development of Th17 cells (11) and oncogenesis (12)(13)(14)(15)(16)(17). It has been found that USP17 is highly expressed in several types of tumor, including colon, esophageal and cervical tumors (14).…”

CLPTM1L induces estrogen receptor β signaling-mediated radioresistance in non-small cell lung cancer cells

“…Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related death worldwide; more than 200,000 new cases are diagnosed annually, of which 16% of patients survive longer than 5 years [ 1 , 2 ]. NSCLC is the most prevalent histological type of lung cancer, accounting for 85% of all cases; it comprises large cell carcinomas, squamous cell carcinomas, and adenocarcinomas [ 3 , 4 ].…”