[Effects of interleukin-12 transfection on proliferation of ovarian cancer SKOV3 cells in vitro and in vivo].
OBJECTIVE
The incidence, recurrence rate, and metastasis rate of malignant ovarian tumors are high. Interleukin-12 (IL-12) has antitumor effect. This study was to investigate the effects of IL-12 on the proliferation of human ovarian carcinoma SKOV3 cells in vitro and in vivo.


METHODS
The plasmid containing mouse IL-12 gene was transfected into SKOV3 cells (SKOV3/IL-12). Blank plasmid-transfected SKOV3 cells (SKOV3/neo) and untransfected SKOV3 cells were used as controls. The expression of IL-12 protein was detected by ELISA. The proliferation inhibition rate and population doubling time (PDT) of SKOV3 cells were evaluated by MTT assay. SKOV3/IL-12, SKOV3/neo and SKOV3 cells were inoculated in nude mice subcutaneously. Tumor growth was recorded. The serum levels of IL-12 and interferon-gamma (IFN-gamma) in mice was detected by ELISA. The expression of vascular endothelial growth factor (VEGF) and IFN-gamma-inducible protein 10 (IP-10), and microvessel density (MVD) in tumor tissues was detected by immunohistochemistry.


RESULTS
After transfection, the protein level of IL-12 was significantly higher in SKOV3/IL-12 cells than in SKOV3/neo and SKOV3 cells [(473.0+/-38.0) pg/ml vs. (16.0+/-1.3) pg/ml and (16.0+/-1.2) pg/ml at 48 h, (522.0+/-32.0) pg/ml vs. (18.0+/-1.6) pg/ml and (17.0+/-1.4) pg/ml at 60 h, P<0.01]. The proliferation inhibition rate of SKOV3/IL-12 cells was significantly higher than those of SKOV3/neo and SKOV3 cells (63.7% vs. 0% and 0%, P<0.01). The PDT was significantly longer in SKOV3/IL-12 cells than in SKOV3/neo and SKOV3 cells [(45.8+/-2.7) h vs. (27.6+/-2.2) h and (28.2+/-2.1) h, P<0.01]. In nude mice, the tumor formation rate of SKOV3/IL-12 cells was lower than those of control cells (5/8 vs. 8/8 and 8/8)û the tumor formation time was significantly longer in SKOV3/IL-12 group than in SKOV3/neo group and SKOV3 group [(15.0+/-5.0) days vs. (7.9+/-3.2) days and (7.8+/-2.4) days, P<0.01]. The volume and weight of tumors and the body weight of mice were significantly lower in SKOV3/IL-12 group than in SKOV3/neo group and SKOV3 group (P<0.01). The serum levels of IL-12 and IFN-gamma were significantly higher in SKOV3/IL-12 group than in SKOV3/neo group and SKOV3 group (P<0.01). The positive rate of VEGF and MVD were significantly lower and the positive rate of IP-10 was higher in SKOV3/IL-12 group than in SKOV3/neo group and SKOV3 group (P<0.01).


CONCLUSIONS
Transfection of IL-12 can inhibit the proliferation and suppress the tumorigenic ability of SKOV3 cells. IL-12 can promote IFN-gamma to induce IP-10 production, thereafter, inhibit neovascularization in tumors.
Wang
Jing
J
Department of Gynecology, The Affiliated Tumor Hospital, Harbin Medical University, Harbin, Heilongjiang, 150040, PR China.
Zhang
Chang-Qing
CQ
Liu
Juan
J
Sui
Li-Hua
LH
D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D054357:Chemokine CXCL10 / Q000097:blood; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D018664:Interleukin-12 / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic; D010051:Ovarian Neoplasms / Q000097:blood / Q000378:metabolism / Q000473:pathology*; D010957:Plasmids; D011897:Random Allocation; D014162:Transfection; D047368:Tumor Burden; D042461:Vascular Endothelial Growth Factor A / Q000097:blood
D054357:Chemokine CXCL10; D042461:Vascular Endothelial Growth Factor A; D018664:Interleukin-12; D007371:Interferon-gamma