Department of General Surgery, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, China.
Chin Med J (Engl). 2009 Nov 5;122(21):2636-42.
Both survivin and lung resistance related protein (LRP) are related to the chemoresistances in hepatocellular carcinoma (HCC). But the relationship between survivin and LRP is indefinite. The aim of this study was to investigate the effects of down-regulation of survivin on LRP expressions and the reversal of chemoresistances in HCC both in vitro and in vivo.
The expressions of survivin were detected by RT-PCR and Western blotting in HCC cell line SMMC-7721 and SMMC-7721/ADM. The sensitivities of these two cell lines to ADM were evaluated by MTT assays. SiRNA which targeted survivin was transfected into SMMC-7721/ADM cells, then the sensitivity of SMMC-7721/ADM cells to ADM and the expressions of survivin and LRP were detected respectively. SMMC-7721/ADM cells were transplanted subcutaneously into nude mice to establish xenograft tumors. Antitumor activities of RNA interference (RNAi) targeting survivin, various doses of ADM and combination therapies were observed respectively. Possible toxicities were evaluated. LRP expression changes were tested. Student's t test was used for evaluating statistical significance.
The expressions of survivin in SMMC-7721/ADM cell line showed significant elevation compared to those in SMMC-7721 cell line (P < 0.05). Positive siRNA down-regulated the expressions of survivin significantly (P < 0.05). SiRNA targeting survivin could sensitize SMMC-7721/ADM cells to ADM and down-regulate the expressions of LRP significantly (P < 0.05). Growths of the tumors were significantly inhibited in positive siRNA group as compared with those in the control group from the 8th day (P < 0.05). Combination therapies caused significant tumor inhibitions compared with tumors of nude mice in the other three groups respectively (P < 0.05). No toxicities were found in nude mice treated by siRNA and combination therapies. The expressions of LRP were markedly reduced in tumors treated with siRNA targeting survivin (P < 0.05).
Down regulation of survivin gene by RNAi can increase chemosensitivity of HCC both in vitro and in vivo. The reversal of drug resistance may be reduced through the inhibitions of LRP.
存活素和肺耐药相关蛋白（LRP）均与肝癌（HCC）的化疗耐药性有关。但是存活素和 LRP 之间的关系尚不确定。本研究的目的是探讨下调存活素对 HCC 细胞系体内外 LRP 表达和化疗耐药性逆转的影响。
采用 RT-PCR 和 Western blot 检测 HCC 细胞系 SMMC-7721 和 SMMC-7721/ADM 中存活素的表达。MTT 法评估两细胞系对 ADM 的敏感性。将靶向存活素的 siRNA 转染 SMMC-7721/ADM 细胞，然后分别检测 SMMC-7721/ADM 细胞对 ADM 的敏感性、存活素和 LRP 的表达。将 SMMC-7721/ADM 细胞皮下移植入裸鼠建立异种移植瘤。观察靶向存活素的 RNA 干扰（RNAi）、不同剂量 ADM 及联合治疗的抗肿瘤活性，并评估可能的毒性。检测 LRP 表达变化。采用 Student's t 检验进行统计学分析。
SMMC-7721/ADM 细胞系中存活素的表达明显高于 SMMC-7721 细胞系（P < 0.05）。阳性 siRNA 能显著下调存活素的表达（P < 0.05）。靶向存活素的 siRNA 能使 SMMC-7721/ADM 细胞对 ADM 敏感，并显著下调 LRP 的表达（P < 0.05）。与对照组相比，从第 8 天开始，阳性 siRNA 组肿瘤生长明显受到抑制（P < 0.05）。与其他三组裸鼠肿瘤相比，联合治疗组肿瘤抑制作用显著（P < 0.05）。siRNA 和联合治疗组裸鼠未见毒性反应。靶向存活素的 siRNA 治疗后肿瘤 LRP 表达明显降低（P < 0.05）。
RNAi 下调存活素基因可增加 HCC 体内外的化疗敏感性。通过抑制 LRP，可能逆转耐药性。
