Function of death associated protein kinase(DAPK) in colorectal cancer chemoresistance.
- Author:
Qiang FU
1
;
Yonglei ZHANG
;
Jing CHENG
;
Xiaobing CHEN
;
Jianguo XIE
;
Suxia LUO
Author Information
- Publication Type:Journal Article
- MeSH: ATP-Binding Cassette, Sub-Family B, Member 1; Antineoplastic Agents; Apoptosis; Cell Proliferation; Colorectal Neoplasms; drug therapy; enzymology; Death-Associated Protein Kinases; metabolism; Drug Resistance, Neoplasm; Fluorouracil; Genetic Vectors; HCT116 Cells; Humans; RNA, Messenger; RNA, Small Interfering; Transfection
- From: Chinese Journal of Gastrointestinal Surgery 2014;17(11):1101-1105
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate the role of death associated protein kinase(DAPK) in colon cancer drug-resistance.
METHODSImmunohistochemistry was used to detect DAPK expression in colon carcinoma tissues of 61 cases and adjacent tissues of 32 cases. 5-fluorouracil (5-FU)-induced drug-resistant colon cancer cell lines HCT116/5-FU model was established. DAPK-siRNA was transfected into cells to down-regulate the DAPK gene expression (DAPK-siRNA grouyp), FAM-siRNA was transfected as control group, and DAPK over-expression plasmid vectors were constructed to up-regulate the DAPK gene expression(DAPK over-expression group). Real-time quantitative PCR and Western blotting were used to examine the mRNA and protein expression levels of DAPK, multidrug resistance protein (MRP) and P- glycoprotein (P-gp). MTT and flow cytometry were used to detect cell proliferation and apoptosis for cells treated with 5-FU (8 mg/L) and cells without treatment of 5-FU in 3 groups respectively.
RESULTSPositive expression rate of DAPK in colon cancer tissues was significantly lower than that in adjacent normal tissues [18.0% (11/61) vs. 90.6% (29/32), P < 0.05]. Compared with FAM-siRNA group, DAPK mRNA and protein expression levels were significantly lower in DAPK-siRNA group, but significantly higher in DAPK over-expression group (P<0.05). After treatment of 5-FU, cell proliferation was significantly inhibited, but cell apoptosis was significantly increased in DAPK over-expression group compared to FAM-siRNA group (P < 0.05). Cell proliferation and apoptosis were not significantly different between DAPK siRNA and FAM-siRNA groups (all P < 0.05). Compared with FAM-siRNA group, DAPK over-expression could significantly reduce the mRNA and protein levels of MRP and P-gp, whereas DAPK siRNA had no obvious such effects.
CONCLUSIONDAPK can inhibit the proliferation and promote the apoptosis in drug-resistant colon cancer cells, and it probably enhances the sensitivity of cancer cells to drugs by down-regulating the mRNA and protein levels of MRP and P-gp.
