Abstract 899: Characterization and establishment of a drug-resistant human lung cancer model.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Introduction In 2012, lung cancer is expected to be the leading cause of cancer death in the United States, accounting for about 28% of all cancer deaths. Eribulin mesylate (Halaven®) is a microtubule-dynamics inhibitor approved for third line clinical use in patients with heavily pretreated metastatic breast cancer based upon statistically significant increase in median overall survival (OS) compared to treatment of physician's choice. Methods H522-T1 human non-small cell lung cancer subcutaneous xenograft tumors were established in nude mice that were subsequently treated with a sub-optimal dose of eribulin (half MTD). Two to three days after final drug administration, residual tumors were harvested and implanted again into naive nude mice. These tumors were treated again with the same regimen and the residual tumors were again collected and re-implanted into naive nude mice for another cycle of selection. A cell line named H522-T5er was established from the 4th cycle of residual tumor. Results In vitro, H522-T5er showed strikingly increased resistance to eribulin compared to the parental cell line (82-fold). In vivo, H522-T5er xenograft tumors also showed high resistance to eribulin dosed at MTD. Further flow cytometry analysis identified enrichment of a CD44+/CD24- subpopulation of H522-T5er cells, suggesting stem/progenitor cell properties of H522-T5er. Expression profiling analysis of parental tumors and drug-selected residual tumors, as well as H522-T1 and H522-T5er cells were conducted. A total of 71 genes with more than 2-fold changes were identified in the comparison between parental tumor and drug-selected residual tumors, while 187 genes showed more than 2-fold changes between H522-T1 and H522-T5er cells. Twelve genes were identified in both comparison and only 5 of them were changed in the same direction. Protein levels of several drug pumps reported to be frequently involved in drug resistance were also determined by Western blot analysis. No significant increase of Pgp (1.3-fold) was identified in H522-T5er cells. Both BCRP and LRP showed about a 2-fold increase in H522-T5er cells, while a slight decrease of MRP1 (20%) was observed in H522-T5er cells. Conclusions An eribulin-resistant cell line, not characterized by significant increase of Pgp expression, has been generated. It provides a valuable tool to develop and test agents which can target residual tumor after eribulin treatment. Citation Format: Kuan-Chun Huang, Judith Oestreicher, Natalie Twine, Winnie Lee, Xingfeng Bao, Sergei Agoulnik, Bruce A. Littlefield, Mary Woodall-Jappe, Kenichi Nomoto. Characterization and establishment of a drug-resistant human lung cancer model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 899. doi:10.1158/1538-7445.AM2013-899