Wang Jing, Zhang Chang-Qing, Liu Juan, Sui Li-Hua
Department of Gynecology, The Affiliated Tumor Hospital, Harbin Medical University, Harbin, Heilongjiang, 150040, PR China.
Ai Zheng. 2007 Dec;26(12):1292-8.
BACKGROUND & 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.
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.
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).
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.
恶性卵巢肿瘤的发病率、复发率及转移率均较高。白细胞介素12（IL-12）具有抗肿瘤作用。本研究旨在探讨IL-12对人卵巢癌SKOV3细胞体外及体内增殖的影响。
将含小鼠IL-12基因的质粒转染至SKOV3细胞（SKOV3/IL-12）。转染空质粒的SKOV3细胞（SKOV3/neo）和未转染的SKOV3细胞作为对照。采用ELISA法检测IL-12蛋白表达。采用MTT法评估SKOV3细胞的增殖抑制率和群体倍增时间（PDT）。将SKOV3/IL-12、SKOV3/neo和SKOV3细胞皮下接种于裸鼠。记录肿瘤生长情况。采用ELISA法检测小鼠血清中IL-12和干扰素-γ（IFN-γ）水平。采用免疫组织化学法检测肿瘤组织中血管内皮生长因子（VEGF）、IFN-γ诱导蛋白10（IP-10）的表达及微血管密度（MVD）。
转染后，SKOV3/IL-12细胞中IL-12蛋白水平显著高于SKOV3/neo和SKOV3细胞[48 h时分别为(473.0±38.0) pg/ml vs. (16.0±1.3) pg/ml和(16.0±1.2) pg/ml，60 h时分别为(522.0±32.0) pg/ml vs. (18.0±1.6) pg/ml和(17.0±1.4) pg/ml，P<0.01]。SKOV3/IL-12细胞的增殖抑制率显著高于SKOV3/neo和SKOV3细胞（63.7% vs. 0%和0%，P<0.01）。SKOV3/IL-12细胞的PDT显著长于SKOV3/neo和SKOV3细胞[(45.8±2.7) h vs. (27.6±2.2) h和(28.2±2.1) h，P<0.01]。在裸鼠中，SKOV3/IL-12细胞的成瘤率低于对照细胞（5/8 vs. 8/8和8/8）；SKOV3/IL-12组的成瘤时间显著长于SKOV3/neo组和SKOV3组[(15.0±5.0)天 vs. (7.9±3.2)天和(7.8±2.4)天，P<0.01]。SKOV3/IL-12组肿瘤的体积、重量及小鼠体重均显著低于SKOV3/neo组和SKOV3组（P<0.01）。SKOV3/IL-12组小鼠血清中IL-12和IFN-γ水平显著高于SKOV3/neo组和SKOV3组（P<0.01）。SKOV3/IL-12组VEGF和MVD的阳性率显著低于SKOV3/neo组和SKOV3组，IP-10的阳性率高于SKOV3/neo组和SKOV3组（P<0.01）。
转染IL-12可抑制SKOV3细胞的增殖并抑制其致瘤能力。IL-12可促进IFN-γ诱导IP-10产生，进而抑制肿瘤新生血管形成。
