[Expression of C1QBP gene and its correlation with drug resistance in human resistance choriocarcinoma cell line].

Objective: To examine the complement component 1 Q subcomponent-binding protein (C1QBP) gene expression in human resistance choriocarcinoma cell lines and its parental cell line JeG-3, and to investigate whether silence C1QBP by small interference RNA could reverse the resistance of human resistance choriocarcinoma cell lines to its relevant chemotherapy drugs.

Methods: Expression of C1QBP mRNA and protein in cells were detected by real- time fluorogenic quantitative PCR and western blot, respectively. The difference of C1QBP expression was compared between human resistance choriocarcinoma cell lines and its parental cell line JeG-3. Sub-cellular location was proved by confocal immunofluorescence microscopy. A lentiviral vector containing short hairpin RNA (shRNA) targeting C1QBP was constructed and cotransfected with the packaging plasmid mixture into 293T cells by lipofectamine 2000. The human resistance choriocarcinoma cell lines were infected with the packaged lentivirus. Real- time fluorogenic quantitative PCR and western blot were used to validate whether the C1QBP gene expression was silenced. The cell counting kit 8 (CCK8) was used to determine the drug sensitivity.

Results: (1) The C1QBP mRNA expression levels among four human resistance choriocarcinoma cell lines [JeG-3/floxuridiuum (FUDR), JeG- 3/methotrexate (MTX), JeG-3/etoposide (VP), JeG-3/dactinomycin (KSM)] were 2.520 ±0.680, 1.770 ± 0.230, 1.940 ± 0.090 and 1.740 ± 0.350 folds compared to that in JeG- 3 cells. The C1QBP protein was higher expression level in human resistance choriocarcinoma cell lines than that in JeG-3. The immunofluorescence methods and confocal analysis showed that C1QBP localized predominantly in the mitochondrial matrix. (2) The C1QBP mRNA expression in JeG-3/FUDR cells after infected with lentiviral vector were decreased by 93.1% (P < 0.01). The protein expression of C1QBP in JeG-3/FUDR cells after infected with lentiviral vector were almost completely suppressed. The resistance indexes of four human resistance choriocarcinoma cell lines (JeG-3/FUDR, JeG-3/MTX, JeG-3/VP, JeG-3/KSM) were respectively 86.3% , 93.9% , 92.8% and 89.9%, which were decreased remarkably by knockdown the C1QBP expression (P < 0.05).

Conclusions: C1QBP is overexpressed in human resistance choriocarcinoma cell lines compared with parental cell line JeG-3. Inhibition of C1QBP by lentivirus- mediated small interference RNA could effectively reverses the resistance of human resistance choriocarcinoma cell lines to its relevant chemotherapy drugs.