Huang Hai-wen, Chen Ping, Li Bing-zong, Fu Jin-xiang, Li Jun, Zhang Xiao-hui, Liu Rui, Fan Yin-yin, Zhang Hong, Chow Howard C H, Leung Anska Y H, Liang Raymond
Department of Hematology, the Second Affiliated Hospital of Soochow University, Suzhou, China.
Zhonghua Zhong Liu Za Zhi. 2012 Sep;34(9):652-7. doi: 10.3760/cma.j.issn.0253-3766.2012.09.003.
To observe the effect of rosiglitazone (RGZ) and all-trans-retinoic acid (ATRA) on the growth of myeloma xenograft in nude mice and to explore the influence of RGZ and ATRA on VEGF expression and angiogenesis in the tumor.
VEGF gene expression in myeloma cell line U266 cells was analyzed by semi-quantitative RT-PCR after incubation with RGZ, ATRA, or RGZ + ATRA for 24 h. Myeloma xenograft was established by subcutaneous injection of 10(7) U266 cells in the scapula area of 4-week old nude mice. 7 days later, the nude mice were administered with RGZ, ATRA or RGZ + ATRA, respectively, by intraperitoneal injection once every day for 21 days. The control mice were given equal volume of normal saline instead of the drug. On the 21(st) day of treatment, the mice were sacrificed and the tumors were taken off, and the tumor volume and weight were measured. The tumors were examined by histopathology with HE staining, and microvessel density (MVD), CD34 and VEGF expression in the tumors were analyzed by immunohistochemical staining.
VEGF mRNA was highly expressed in U266 cells and was decreased in a dose-dependent manner after incubation with RGZ. The VEGF mRNA level was further more decreased after RGZ + ATRA treatment. Xenografts of U266 cells were developed in all nude mice. The volume and weight of xenografts in the RGZ group were (785 ± 262) mm(3) and (1748 ± 365) mg, respectively, significantly lower than those of the control group (both P < 0.01). More significant inhibition was in the RGZ + ATRA group, (154 ± 89) mm(3) and (626 ± 102) mg, respectively, both were P < 0.05 vs. the RGZ group. RGZ inhibited the angiogenesis in U266 xenografts and immunohistochemical staining showed that the tumor MVD and VEGF expression were significantly decreased by RGZ treatment, and further more inhibited in the RGZ + ATRA group. VEGF protein was expressed in all xenografts in the nude mice. Its immunohistochemical staining intensity was 2.20 ± 0.40 in the control group, significantly higher than that of 1.48 ± 0.37 in the RGZ group (P < 0.01), and that of RGZ + ATRA group was 0.58 ± 0.26, further significantly lower than that of the RGZ group (P < 0.01). CD34 was expressed in all xenografts, most highly in the control group and lowest in the RGZ + ATRA group. The microvessel density (MVD) was highest in the control group (56.4 ± 15.2), significantly lower in the RGZ group (44.6 ± 11.2) (P < 0.05), and lowest in the RGZ + ATRA group (21.5 ± 8.6, P < 0.01).
The growth of myeloma cells can also be inhibited by RGZ and ATRA in nude mice in vivo. In addition to differentiation and apoptosis induction, RGZ can inhibit the formation of myeloma xenograft probably also through the downregulation of VEGF expression and subsequent angiogenesis.
观察罗格列酮（RGZ）和全反式维甲酸（ATRA）对骨髓瘤裸鼠移植瘤生长的影响，探讨RGZ和ATRA对肿瘤组织中血管内皮生长因子（VEGF）表达及血管生成的影响。
将骨髓瘤细胞株U266细胞分别用RGZ、ATRA或RGZ + ATRA孵育24 h后，采用半定量逆转录-聚合酶链反应（RT-PCR）分析VEGF基因表达。将10(7)个U266细胞接种于4周龄裸鼠肩胛区皮下，建立骨髓瘤移植瘤模型。7 d后，分别对裸鼠腹腔注射RGZ、ATRA或RGZ + ATRA，每天1次，共21 d。对照组给予等体积生理盐水。治疗21 d后处死小鼠，取出肿瘤，测量肿瘤体积和重量。采用苏木精-伊红（HE）染色进行组织病理学检查，免疫组织化学染色分析肿瘤微血管密度（MVD）、CD34及VEGF表达。
U266细胞中VEGF mRNA高表达，经RGZ孵育后呈剂量依赖性降低。RGZ + ATRA处理后VEGF mRNA水平进一步降低。所有裸鼠均成功建立U266细胞移植瘤模型。RGZ组移植瘤体积和重量分别为(785 ± 262) mm(3)和(1748 ± 365) mg，显著低于对照组（均P < 0.01）。RGZ + ATRA组抑制作用更显著，分别为(154 ± 89) mm(3)和(626 ± 102) mg，与RGZ组比较均P < 0.05。RGZ抑制U266移植瘤血管生成，免疫组织化学染色显示，RGZ处理后肿瘤MVD及VEGF表达显著降低，RGZ + ATRA组抑制作用更强。裸鼠移植瘤均有VEGF蛋白表达。对照组免疫组织化学染色强度为2.20 ± 0.40，显著高于RGZ组的1.48 ± 0.37（P < 0.01），RGZ + ATRA组为0.58 ± 0.26，进一步显著低于RGZ组（P < 0.01）。所有移植瘤均有CD34表达，对照组最高，RGZ + ATRA组最低。微血管密度（MVD）对照组最高（56.4 ± 15.2），RGZ组显著降低（44.6 ± 11.2）（P < 0.05），RGZ + ATRA组最低（21.5 ± 8.6，P < 0.01）。
RGZ和ATRA在体内可抑制裸鼠骨髓瘤细胞生长。RGZ除诱导分化和凋亡外，可能还通过下调VEGF表达及随后的血管生成抑制骨髓瘤移植瘤的形成。
