Establishment of an acquired lorlatinib-resistant cell line of non-small cell lung cancer and its mediated resistance mechanism

This study demonstrated that the combination of p53 protein agonist and lorlatinib may provide a new therapeutic strategy for NSCLC patients with lorlatinib resistance and TP53 mutation. Furthermore, the results also provide guidance for selecting optimal chemo-regimens for NSCLC patients after ALK-TKIs failure.

A lorlatinib-resistant NSCLC cell line SNU-2535LR was generated by gradually increasing dose of lorlatinib to crizotinib-resistant cell line SNU-2535 in vitro. To study the resistance mechanism of SNU-2535LR cells, we applied CCK-8 assay to detect the sensitivity of crizotinib and the reverse effect of APR-246, a p53 activator, on lorlatinib-induced resistance and different chemotherapy drugs to SNU-2535LR cells. We also detected the expressions of EML4-ALK-related proteins of SNU-2535LR cells via western blot.Please confirm that author names have been identified correctly and are presented in the right order.Dear Editor: I have carefully confirmed that the author names have been identified correctly and are presented in right order.Thank you very much! Your sincerely BoXie

Although lorlatinib, the third generation of echinoderm microtubule protein 4-anaplastic lymphoma kinase (EML4-ALK) tyrosine kinase inhibitor (TKI), overcame the previous generation ALK-TKIs' drug resistance problems, but the mechanism of lorlatinib resistance remained unclear. Furthermore, optimal chemotherapy for lorlatinib-resistant non-small cell lung cancer (NSCLC) patients was still unknown.

The sensitivity of SNU-2535LR cells to lorlatinib was decreased significantly than that of SNU-2535 cells. EML4-ALK fusion was decreased both at protein level and DNA level in SNU-2535LR cells. More interesting, the crizotinib-resistant mutation ALK p.G1269A disappeared, while new TP53 mutation emerged in SNU-2535LR cells. APR-246 can reverse the lorlatinib resistance in SNU-2535LR cells, with a reversal index of 4.768. Compared with SNU-2535 cells, the sensitivity of SNU-2535LR cells to gemcitabine, docetaxel and paclitaxel was significantly increased (P < 0.05), but decreased to cisplatin (P < 0.05).