High pemetrexed sensitivity of docetaxel-resistant A549 cells is mediated by TP53 status and downregulated thymidylate synthase

doi:10.3892/or.2017.5951

CNU IR > Pharmacy and Science > Dept. of Food Science & Technology > Periodical Articles > Item 310902800/31744

Please use this identifier to cite or link to this item: https://ir.cnu.edu.tw/handle/310902800/31744

Title:	High pemetrexed sensitivity of docetaxel-resistant A549 cells is mediated by TP53 status and downregulated thymidylate synthase
Authors:	Kuo, Wei-Ting Tu, Dom-Gene Chiu, Ling-Yen Sheu, Gwo-Tarng Wu, Ming-Fang
Contributors:	Natl Yang Ming Univ, Inst Clin Med Chia Yi Christian Hosp, Dept Surg Chia Yi Christian Hosp,Ditmanson Med Fdn, Dept Nucl Med Chia Nan Univ Pharm & Sci, Dept Food Sci & Technol Chang Jung Christian Univ, Coll Hlth Sci Chung Shan Med Univ Hosp, Inst Med Chung Shan Med Univ Hosp, Sch Med Chung Shan Med Univ Hosp, Div Med Oncol Chung Shan Med Univ Hosp, Div Chest Med
Keywords:	docetaxel pemetrexed thymidylate synthase TP53 chemoresistance
Date:	2017-11
Issue Date:	2018-11-30 15:55:04 (UTC+8)
Publisher:	Spandidos Publ Ltd
Abstract:	The chemoresistance of non-small cell lung cancer (NSCLC) that occurs in docetaxel (DOC) chemotherapy substantially decreases the survival of patients. To overcome DOC-induced chemoresistance, we established DOC-selected A549 lung cancer sublines (A549/D16 and A549/D32) and revealed that both sublines were cross-resistant to vincristine (VCR) and doxorubicin (DXR). Notably, both sublines were more sensitive to pemetrexed (PEM) than parental cells according to MTT and clonogenic assays. The expression levels of thymidylate synthase (TS) and gamma-glutamyl hydrolase (GGH) were downregulated in DOC-resistant sublines. When exogenous TS was overexpressed in A549/D16 cells, PEM sensitivity was significantly decreased, however it was not decreased by overexpression of exogenous GGH. PEM treatment induced more apoptotic sub-G1 cells in both DOC-resistant sublines and in the in vivo PEM sensitivities of A549/D16 cells. These findings were further confirmed by a xenografted tumor model. To unmask the mediator of TS downregulation, we investigated human lung cancer cell lines that have various TP53 statuses using DOC treatment. The level of TS protein was significantly decreased in wild-type TP53-containing cells with DOC treatment; TS expression levels were not affected in mutant-TP53 and TP53-null cells under the same conditions. Furthermore, when the expression of TP53 was inhibited in A549 cells, the expression level of TS was increased. Our data indicated that DOC activated wild-type TP53 and suppressed TS expression under continuous DOC exposure. Therefore, the expression of TS remained at low levels in DOC-resistant A549 cancer cells. Our data revealed that for lung cancer with DOC resistance and wild-type TP53 status, the administration of PEM as a second-line agent to overcome DOC-resistance may benefit patients.
Relation:	Oncology Reports, v.38, n.5, pp.2787-2795
Appears in Collections:	[Dept. of Food Science & Technology] Periodical Articles

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