[HTML][HTML] Targeting the degradation of AXL receptor tyrosine kinase to overcome resistance in gefitinib-resistant non-small cell lung cancer

SY Bae, JY Hong, HJ Lee, HJ Park, SK Lee - Oncotarget, 2015 - ncbi.nlm.nih.gov
SY Bae, JY Hong, HJ Lee, HJ Park, SK Lee
Oncotarget, 2015ncbi.nlm.nih.gov
Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-
TKIs), such as gefitinib, remains a major problem in non-small cell lung cancer (NSCLC)
treatment. Increased activation of AXL has been identified as a novel mechanism for
acquired resistance to EGFR-TKIs in NSCLC treatment. However, the cause of uncontrolled
AXL expression is not fully understood. Here, we first demonstrate that AXL is
overexpressed in an acquired gefitinib-resistant cell line (H292-Gef) as a result of slow …
Abstract
Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, remains a major problem in non-small cell lung cancer (NSCLC) treatment. Increased activation of AXL has been identified as a novel mechanism for acquired resistance to EGFR-TKIs in NSCLC treatment. However, the cause of uncontrolled AXL expression is not fully understood. Here, we first demonstrate that AXL is overexpressed in an acquired gefitinib-resistant cell line (H292-Gef) as a result of slow turnover and that AXL is degraded by presenilin-dependent regulated intramembrane proteolysis (PS-RIP). Based on the findings, we attempted to enhance AXL degradation to overcome acquired gefitinib-resistance by the treatment of gefitinib-resistant NSCLC cells with yuanhuadine (YD), a potent antitumor agent in NSCLC. Treatment with YD effectively suppressed the cancer cell survival in vitro and in vivo. Mechanistically, YD accelerated the turnover of AXL by PS-RIP and resulted in the down-regulation of the full-length AXL. Therefore, the modulation of the proteolytic process through degradation of overexpressed AXL may be an attractive therapeutic strategy for the treatment of NSCLC and EGFR-TKI-resistant NSCLC.
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