Induced apoptosis with ultrasound-mediated microbubble destruction and shRNA targeting survivin in transplanted tumors.
BACKGROUND
This study was designed to evaluate the consequences of survivin down-modulation on tumor growth in a nude mice model combined with short hairpin RNA recombinant vector (shRNA) and ultrasound-mediated microbubble destruction (UMMD).


METHODS
BALB/c nude mice were inoculated subcutaneously with cervical cancer cells (HeLa) and tumors (5-10 mm) developed. A shRNA recombinant vector that targeted the survivin gene (survivin-shRNA) was constructed. The mice were divided into three groups (n=6 in each group) and injected with survivin-shRNA: plasmid group (P), plasmid+ultrasound exposure group (P+US), and plasmid+microbubble (SonoVue(R))+ultrasound group (P+UMMD). Protein expression of survivin, proliferating cell nuclear antigen (PCNA), and caspase-3 were investigated by immunohistochemistry, and proliferation index (PI) and apoptotic index (AI) were measured.


RESULTS
The protein expression of survivin and PCNA was markedly downregulated, while caspase-3 was markedly upregulated in the P+UMMD group as compared with that of the P group and P+US group. PI decreased significantly (P<0.05), whereas AI increased remarkably (P<0.01) in the P+UMMD group as compared with that of the P group and P+US group. These data indicate that the combined strategy of UMMD and survivin-shRNA effectively induces silencing of the survivin gene, resulting in inhibition of proliferation and induction of apoptosis in nude mice.


CONCLUSIONS
Survivin could be regarded as an ideal target for anticancer intervention of cervical cancer. The combination of shRNA and UMMD could enhance antitumor efficacy as a result of synergism. This may be a powerful, promising non-viral technology that could be used in tumor gene therapy.
Chen
Zhi-Yi
ZY
Department of Medical Ultrasound, The Third Affiliated Hospital of Guangzhou Medical College, Guangdong, 510150, China. winchen1408@126.com
Liang
Kun
K
Xie
Ming-Xing
MX
Wang
Xin-Fang
XF
Lü
Qing
Q
Zhang
Jing
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000096:biosynthesis; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D045423:Microbubbles; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis* / Q000235:genetics; D009374:Neoplasms, Experimental / Q000473:pathology / Q000628:therapy*; D010743:Phospholipids / Q000494:pharmacology; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D034741:RNA, Small Interfering / Q000235:genetics*; D016037:Single-Blind Method; D013459:Sulfur Hexafluoride / Q000494:pharmacology; D000077022:Survivin; D014465:Ultrasonics
C107489:BIRC5 protein, human; D003287:Contrast Media; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D010743:Phospholipids; D018809:Proliferating Cell Nuclear Antigen; D034741:RNA, Small Interfering; D000077022:Survivin; C420843:contrast agent BR1; D053148:Caspase 3; D013459:Sulfur Hexafluoride