Ad-PUMA sensitizes drug-resistant choriocarcinoma cells to chemotherapeutic agents.
OBJECTIVE
To investigate whether exogenous PUMA expression suppresses the growth of drug-resistant choriocarcinoma cells and sensitizes them to chemotherapeutic agents.


METHODS
An adenovirus expressing PUMA (Ad-PUMA), alone or in combination with chemotherapeutic agents (5-FU, vp16, MTX), was used to treat drug-resistant choriocarcinoma cells jeg-3/vp16 and parental jeg-3. The growth inhibitory and proapoptotic effects of Ad-PUMA both in vitro and in vivo were examined. The mechanisms of PUMA-mediated growth suppression and apoptosis were investigated by an analysis of caspase 3 activation and the change of mitochondrial membrane potential. The levels of PUMA, p53 and caspase 3 were detected by Western blotting.


RESULTS
PUMA was expressed lower in jeg-3/vp16 than in jeg-3. jeg-3/vp16 responded much less sensitively to 5-FU and vp16 treatment than jeg-3, though PUMA was up-regulated in both cells. Exogenous PUMA expression resulted in potent growth suppression of jeg-3/vp16 and jeg-3 through induction of apoptosis. Ad-PUMA sensitized jeg-3 and jeg-3/vp16 to chemotherapeutic agents. When Ad-PUMA 10MOI and 5-FU, vp16 or MTX were combined respectively, IC50 of drugs decreased by 8.66-, 18.66- and 13.06-fold compared with those treated by anticancer drugs alone in jeg-3/vp16, while in jeg-3, IC50 decreased only by 1.80-, 1.78- and 2.76-fold. Ad-PUMA restored the sensitivity of choriocarcinoma cells to chemotherapeutic agents by enhancing apoptosis induced by anticancer drugs. Similar results could be observed in vivo. Xenograft tumors were inhibited by Ad-PUMA or vp16. In the drug-resistant group, the inhibitory rate increased from 14.57% to 78.93% in vp16 and vp16 combined with Ad-PUMA subgroups. While in the parental group, the inhibitory rate increased but slightly, from 66.39% to 71.56%.


CONCLUSIONS
PUMA is an important player in the therapeutic responses to chemotherapeutic agents of choriocarcinoma cells. In addition to its role in inhibiting tumor growth, low dose of Ad-PUMA significantly restored the sensitivity of choriocarcinoma cells to chemotherapeutic agents in vitro and in vivo. Exogenous PUMA is potentially useful as a sensitizer in treating drug-resistant choriocarcinoma.
Chen
Yan
Y
State Key Laboratory of Molecular Oncology, Cancer Institute, Peking Union Medical College and Chinese Academy of Medical Science, Beijing 100021, China.
Qian
Haili
H
Wang
Haijuan
H
Zhang
Xueyan
X
Fu
Ming
M
Liang
Xiao
X
Ma
Yan
Y
Zhan
Qimin
Q
Lin
Chen
C
Xiang
Yang
Y
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis / Q000235:genetics*; D048708:Cell Growth Processes / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002822:Choriocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000628:therapy*; D003131:Combined Modality Therapy; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology; D051379:Mice; D008819:Mice, Nude; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D014594:Uterine Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000628:therapy*; D023041:Xenograft Model Antitumor Assays
D051017:Apoptosis Regulatory Proteins; C438378:BBC3 protein, human; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D005047:Etoposide; D005472:Fluorouracil; D008727:Methotrexate