Wenxiu Yao1, Liyang Wang1, Huan Huang2, Xin Li1, Pinjia Wang1, Kun Mi3, Jia Cheng3, Huifen Liu3, Cuirong Gu3, Lingxiao Huang3, Jianming Huang4. 1. Department of Medical oncology, Sichuan Cancer Hospital, Medical School of University of Electronic Science and Technology of China, Chengdu, 610041, People's Republic of China. 2. Department of Medical oncology, Wuming Hospital Affiliated to Guangxi Medical University, Nanning, 530000, China. 3. Department of Biochemistry & Molecular Biology, Sichuan Cancer Insititute, No.55, Section 4, South Renmin Road, Chengdu, 610041, People's Republic of China. 4. Department of Biochemistry & Molecular Biology, Sichuan Cancer Insititute, No.55, Section 4, South Renmin Road, Chengdu, 610041, People's Republic of China. hjianming@yahoo.com.
Abstract
BACKGROUND: The enrichment of cancer stem cell-like cells (CSCs) has been considered to be responsible for tumor progression after an initial response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small cell lung adenocarcinoma (NSCLC/ADC). CSCs with ALDH1A1bright /CD44high expression contribute to the TKIs resistance in NSCLC/ADC cells. All-trans retinoic acid (ATRA) has been shown to be a potential targeted therapy against CSCs due to its ability to inhibit ALDH1A1 activity. We therefore investigated whether ATRA could circumvent the resistance to improve the response to gefitinib in NSCLC/ADC cells. METHODS: Treatment of NSCLC/ADC A549 and H1650 cells with gefitinib enriched the gefitinib surviving cells (GSCs). The expression of ALDH1A1 and CD44 and the IC50 values for gefitinib were determined by flow cytometry (FCM) and crystal violet assay in GSCs and ATRA-treated GSCs, respectively. Using DEAB as the positive control, direct inhibitory effect of ATRA on ALDH1A1 activity was determined by ALDEFLUOR assay, RESULTS: GSCs showed higher expression of ALDH1A1 and CD44 and IC50 values for gefitinib than their respective parental cells, suggesting that gefitinib can lead to propagation of CSC-enriched gefitinib-resistant cells. Treatment with ATRA was found to significantly reduce the increased expression of ALDH1A1 and CD44 and the IC50 values for gefitinib in A549GSC and H1650GSC cells, and ATRA could directly inhibit active ALDH1A1 as compared to DEAB. CONCLUSION: Our findings suggest that combination treatment with ATRA prevents gefitinib-induced enrichment of ALDH1A1bright/CD44high CSCs and enhances gefitinib-induced growth inhibition of NSCLC/ADC cells.
BACKGROUND: The enrichment of cancer stem cell-like cells (CSCs) has been considered to be responsible for tumor progression after an initial response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small cell lung adenocarcinoma (NSCLC/ADC). CSCs with ALDH1A1bright /CD44high expression contribute to the TKIs resistance in NSCLC/ADC cells. All-trans retinoic acid (ATRA) has been shown to be a potential targeted therapy against CSCs due to its ability to inhibit ALDH1A1 activity. We therefore investigated whether ATRA could circumvent the resistance to improve the response to gefitinib in NSCLC/ADC cells. METHODS: Treatment of NSCLC/ADCA549 and H1650 cells with gefitinib enriched the gefitinib surviving cells (GSCs). The expression of ALDH1A1 and CD44 and the IC50 values for gefitinib were determined by flow cytometry (FCM) and crystal violet assay in GSCs and ATRA-treated GSCs, respectively. Using DEAB as the positive control, direct inhibitory effect of ATRA on ALDH1A1 activity was determined by ALDEFLUOR assay, RESULTS:GSCs showed higher expression of ALDH1A1 and CD44 and IC50 values for gefitinib than their respective parental cells, suggesting that gefitinib can lead to propagation of CSC-enriched gefitinib-resistant cells. Treatment with ATRA was found to significantly reduce the increased expression of ALDH1A1 and CD44 and the IC50 values for gefitinib in A549GSC and H1650GSC cells, and ATRA could directly inhibit active ALDH1A1 as compared to DEAB. CONCLUSION: Our findings suggest that combination treatment with ATRA prevents gefitinib-induced enrichment of ALDH1A1bright/CD44high CSCs and enhances gefitinib-induced growth inhibition of NSCLC/ADC cells.
Authors: Susumu Kobayashi; Titus J Boggon; Tajhal Dayaram; Pasi A Jänne; Olivier Kocher; Matthew Meyerson; Bruce E Johnson; Michael J Eck; Daniel G Tenen; Balázs Halmos Journal: N Engl J Med Date: 2005-02-24 Impact factor: 91.245
Authors: Thomas J Lynch; Daphne W Bell; Raffaella Sordella; Sarada Gurubhagavatula; Ross A Okimoto; Brian W Brannigan; Patricia L Harris; Sara M Haserlat; Jeffrey G Supko; Frank G Haluska; David N Louis; David C Christiani; Jeff Settleman; Daniel A Haber Journal: N Engl J Med Date: 2004-04-29 Impact factor: 91.245