Targeting X-linked inhibitor of apoptosis protein inhibits pancreatic cancer cell growth through p-Akt depletion.
OBJECTIVE
To determine whether lentivirus-mediated shRNA targeting the X-linked inhibitor of apoptosis protein (XIAP) gene could be exploited in the treatment of pancreatic cancer.


METHODS
Human pancreatic cancer cells Panc-1, Mia-paca2, Bxpc-3 and SW1990, infected with lentivirus, were analyzed by real-time polymerase chain reaction (PCR). Western blotting was used to examine XIAP protein levels, survivin and p-Akt to confirm the result of real-time PCR and determine the possible mechanism. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure IC₅₀ to determine chemosensitivity to the chemotherapeutic drugs 5-fluorouracil (5-FU) and gemcitabine. A colony assay, MTT assay and a tumorigenicity experiment were used to study cell proliferation in vitro and in vivo. Caspase-3/7 activity, 4',6-diamidino-2-phenylindole-staining and flow cytometric measurements were used to study apoptosis in SW1990 cells.


RESULTS
XIAP proteins were found to be differentially expressed among pancreatic cancer cell lines Panc-1, Mia-paca2, Bxpc-3 and SW1990. Data of real-time PCR and Western blotting showed that XIAP was reduced persistently and markedly by lentivirus-mediated shRNA. Downregulation of XIAP by transfection with XIAP shRNA resulted in decreased p-Akt expression. XIAP shRNA also inhibited the growth of pancreatic cancer cells in vitro and in vivo, enhanced drug-induced apoptosis and increased chemosensitivity to 5-FU and gemcitabine. Results also suggest that inhibition of XIAP and subsequent p-Akt depletion may have an anti-tumor effect through attenuating the ability of cancer cells to survive.


CONCLUSIONS
Lentivirus-mediated gene therapy is an attractive strategy in the treatment of pancreatic cancer and justifies the use of lentivirus in pancreatic cancer gene therapy studies.
Department of Gynaecology and Obstetrics, Xiang Ya Hospital, Central South University, Changsha 410008, Hunan Province, China.
Chun
C
Jiang
Xiao-Ping
XP
Yi
Hong
H
Shen
Yi-Xiong
YX
Li
D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005472:Fluorouracil / Q000494:pharmacology; D015316:Genetic Therapy; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000187:drug effects / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000628:therapy; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000627:therapeutic use; D000077022:Survivin; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000235:genetics* / Q000378:metabolism*; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D034741:RNA, Small Interfering; D000077022:Survivin; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D003841:Deoxycytidine; D051057:Proto-Oncogene Proteins c-akt; D053148:Caspase 3; D053179:Caspase 7; D005472:Fluorouracil; D000093542:Gemcitabine