Abstract
Acquired resistance is unavoidable in lung adenocarcinoma (LUAD) treated with osimertinib, however, the underlying mechanisms remain largely unknown. Here, we report that the long non-coding RNA (lncRNA) APCDD1L-AS1 is upregulated in osimertinib-resistant LUAD tissues and cells and is associated with short survival of osimertinib-resistant LUAD patients. Our data showed that APCDD1L-AS1 upregulation is an independent risk factor for overall survival in patients with osimertinib-resistant LUAD. APCDD1L-AS1 knockdown enhanced osimertinib sensitivity both in vitro and in vivo, whereas APCDD1L-AS1 overexpression promoted osimertinib resistance. Mechanistically, APCDD1L-AS1 accelerates the tricarboxylic acid (TCA) cycle by forming complexes and maintaining the stability of dihydrolipoamide S-succinyltransferase (DLST), which inhibits the ubiquitination and degradation of DLST. Moreover, we demonstrate that hypoxia-inducible factor (HIF)-1α transcriptionally activates APCDD1L-AS1 by binding to the APCDD1L-AS1 promoter region under hypoxic conditions. Overall, our data confirm that APCDD1L-AS1 is upregulated by hypoxia-induced HIF-1α, which drives the TCA cycle by stabilising DLST to further promote osimertinib resistance in LUAD. Our findings provide new insights into the role of HIF-1α/APCDD1L-AS1/DLST axis-related reprogramming of hypoxia and the TCA balance in conferring osimertinib resistance in LUAD and confirm the therapeutic potential for targeting the APCDD1L-AS1.
Keywords:
Hypoxia; Long non-coding RNAs; Lung adenocarcinoma; Osimertinib-resistant; Tricarboxylic acid cycle.