Ali Niapour1,2, Naisana Seyedasli3,4. 1. Digestive Disease Research Center, Ardabil University of Medical Sciences, Ardabil, Iran. ali.niapoor@gmail.com. 2. Research Laboratory for Embryology and Stem Cells, Department of Anatomical Sciences, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran. ali.niapoor@gmail.com. 3. School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, NSW, Australia. 4. The Centre for Cancer Research, The Westmead Institute for Medical Research, Westmead, NSW, Australia.
Abstract
PURPOSE: This study aims to develop a paclitaxel (PTX)-resistant gastric cancer AGS cells (AGS-R) and evaluate the mechanisms of drug resistance. METHODS: AGS cells were successively treated with increasing PTX concentrations. Cross-resistance of established AGS-R, the molecular patterns of cell survival, evasion of apoptosis, epithelial-mesenchymal transition (EMT), and the angiogenic potential were evaluated. RESULTS: AGS-R was induced within six months of PTX exposure. Extension of the treatment resulted in PTX-resistance beyond clinical levels. The established AGS-R showed resistance to vincristine and doxorubicin but not cisplatin. Upon induction of resistance, the expressions of MDR-1 (P < 0.001) and MRP-1 (P < 0.01) genes and proteins significantly increased. AGS-R cells had elevated levels of BCL-2, pro-CASP3, cleaved-NOTCH1, HES1, HEY1, NF-κB, PI3K, p-AKT, HIF-1α, Cyclin A, and B1 as compared with parental cells (at least P < 0.01). The protein levels of BAX, CASP3, P53, and P21 (at least P < 0.01) as well as intracellular ROS (P < 0.001) were reduced in AGS-R. A relative arrest at the G2/M phase (15.8 ± 0.75 vs. 26.7 ± 1.67) of the cell cycle and enrichment of AGS-R cells for CD44 marker (9 ± 0.6 vs. 1 ± 0.8) (P < 0.001) were detected by flow cytometry. While the E-cadherin expression was reduced (P < 0.001), the protein levels of Vimentin, N-cadherin, SLUG, and SNAIL were increased (at least P < 0.05). The angiogenic activity and release of VEGF and MMP2/9 were increased in AGS-R cells relative to the AGS line (P < 0.001). CONCLUSION: AGS-R cells could bypass chemotherapy stress by expressing the genes coding for efflux pumps and altering some key signaling in favor of survival, EMT, and angiogenesis.
PURPOSE: This study aims to develop a paclitaxel (PTX)-resistant gastric cancer AGS cells (AGS-R) and evaluate the mechanisms of drug resistance. METHODS: AGS cells were successively treated with increasing PTX concentrations. Cross-resistance of established AGS-R, the molecular patterns of cell survival, evasion of apoptosis, epithelial-mesenchymal transition (EMT), and the angiogenic potential were evaluated. RESULTS: AGS-R was induced within six months of PTX exposure. Extension of the treatment resulted in PTX-resistance beyond clinical levels. The established AGS-R showed resistance to vincristine and doxorubicin but not cisplatin. Upon induction of resistance, the expressions of MDR-1 (P < 0.001) and MRP-1 (P < 0.01) genes and proteins significantly increased. AGS-R cells had elevated levels of BCL-2, pro-CASP3, cleaved-NOTCH1, HES1, HEY1, NF-κB, PI3K, p-AKT, HIF-1α, Cyclin A, and B1 as compared with parental cells (at least P < 0.01). The protein levels of BAX, CASP3, P53, and P21 (at least P < 0.01) as well as intracellular ROS (P < 0.001) were reduced in AGS-R. A relative arrest at the G2/M phase (15.8 ± 0.75 vs. 26.7 ± 1.67) of the cell cycle and enrichment of AGS-R cells for CD44 marker (9 ± 0.6 vs. 1 ± 0.8) (P < 0.001) were detected by flow cytometry. While the E-cadherin expression was reduced (P < 0.001), the protein levels of Vimentin, N-cadherin, SLUG, and SNAIL were increased (at least P < 0.05). The angiogenic activity and release of VEGF and MMP2/9 were increased in AGS-R cells relative to the AGS line (P < 0.001). CONCLUSION: AGS-R cells could bypass chemotherapy stress by expressing the genes coding for efflux pumps and altering some key signaling in favor of survival, EMT, and angiogenesis.
Authors: Anna Maria Calcagno; Crystal D Salcido; Jean-Pierre Gillet; Chung-Pu Wu; Jennifer M Fostel; Melanie D Mumau; Michael M Gottesman; Lyuba Varticovski; Suresh V Ambudkar Journal: J Natl Cancer Inst Date: 2010-10-08 Impact factor: 13.506