[Influence of survivin gene repression by RNA interference on the radiosensitivity and chemosensitivity to cisplatin of cervical cancer cell HeLa].
OBJECTIVE
To observe the effect of survivin gene repression by RNA interference (RNAi) on the radiosensitivity and the chemosensitivity to cisplatin of cervical cancer cell HeLa.


METHODS
The recombined eukaryotic expression plasmid pSilencer2.1-s2 containing human survivin gene small interference RNA (siRNA) was transfected into human cervical cancer cell line HeLa by using lipofectamine 2000. The expression of survivin gene mRNA and its protein was detected by semi-quantitative RT-PCR and western blot respectively. The changes of caspase-3 activity was assessed by kinase activity test. Cell apoptosis was examined by flow cytometry. The changes of cell radiosensitivity was observed by plate clone formation assay. Cell viability was examined by methyl thiazolyl tetrazolium (MTT) assay and 50% inhibitive concentration (IC(50)) of cisplatin was examined also.


RESULTS
Compared with the cells which were transfected with negative control plasmid (HeLa-NC), pure plasmid (HeLa-U6 neo) and un-transfected cells (HeLa), the expression level of survivin gene mRNA and protein declined evidently in the cells transfected with pSilencer2.1-s2 plasmid (HeLa-s2), the expression inhibitory rates were (62.8 +/- 0.3)% and (60.1 +/- 0.5)%; the caspase-3 activity was enhanced and A(405) was 1.261 +/- 0.043 (P < 0.05); the apoptotic rate was increased obviously (29.23 +/- 1.41)% (P < 0.05). At the same dose of radiation, clone formation rate declined significantly (P < 0.05); at the same concentration of cisplatin, cell viability declined sharply and the IC(50) of cisplatin was (0.873 +/- 0.021) microg/ml (P < 0.05).


CONCLUSIONS
Survivin gene repression by RNAi can enhance caspase-3 activity, induce cell apoptosis, significantly increase the radiosensitivity and chemosensitivity to cisplatin in human cervical cancer cell line HeLa.
Song
Hui
H
Department of Obstetrics and Gynecology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
Xin
Xiao-yan
XY
Xiao
Feng
F
Wang
De-tang
DT
Han
Xing
X
Guo
Hui-ling
HL
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D002945:Cisplatin / Q000494:pharmacology*; D015536:Down-Regulation; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000528:radiation effects; D006367:HeLa Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D020128:Inhibitory Concentration 50; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis* / Q000235:genetics; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D011836:Radiation Tolerance / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077022:Survivin; D014162:Transfection
D000970:Antineoplastic Agents; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000077022:Survivin; D053148:Caspase 3; D002945:Cisplatin