摘要
背景与目的:体外及动物实验表明,生长抑素类似物奥曲肽可抑制肝癌生长,但奥曲肽治疗肝癌的临床疗效并不满意,原因不明。本研究拟探讨有乙型肝炎病毒感染的肝癌是否因其有x基因而改变了对奥曲肽作用的反应及其可能的机制。方法:采用3H鄄TdR掺入法了解细胞DNA合成,细胞免疫化学检测细胞的PCNA表达,AnnexinⅤ荧光标记法及TUNEL法观察细胞的凋亡,Westernblot法检测HepG2和HepG2x细胞ERK及生长抑素受体(somatostatinreceptors,SSTR)的表达。结果:1×10-5～1×10-9mol/L的奥曲肽显著地、浓度依赖性地抑制HepG2细胞3H鄄TdR掺入及PCNA表达(r=-0.917,P<0.01)。奥曲肽也促进HepG2细胞凋亡,其AnnexinⅤ的阳性率为(14.20±2.57)%,对照组仅为(1.18±0.13)%,两组间差异有显著性(P<0.05);TUNEL检测奥曲肽组凋亡指数为(18.8±3.3)%,对照组仅为(3.6±0.9)%,两组间差异有显著性(P<0.05)。奥曲肽及奥曲肽加拉米夫定对HepG2x细胞抑制生长和诱导凋亡作用不明显。HepG2x细胞的SSTR鄄2和SSTR鄄5表达均明显低于HepG2细胞(P<0.01);HepG2x细胞的细胞外信号调节激酶鄄1(extracellularsignal鄄regulatedkinase鄄1,ERK鄄1)和ERK鄄2表达均显著高于HepG2细胞(P<0.05)。奥曲肽未明显改变HepG2x细胞的ERKs表达。结论:转染x基因后的HepG2细胞SSTR鄄2及SSTR鄄5明显下调,导致奥曲肽对HepG2x细胞的生长抑制作用明显降低。
BACKGROUND ＆ OBJECTIVE： In vitro and in vivo experiments have shown that octreotide, a kind of somatostatin analogue, could inhibit hepatocellular carcinoma （HCC） growth. However, its clinical efficacy is unsatisfactory; the reason is unclear. This study was to investigate if some characters of HCC cells transfected with hepatitis B virus （HBV） x gene have altered their response to octreotide, and explore the possible mechanisms.METHODS： The proliferation of HCC cell lines HepG2 and HepG2x （with HBV x gene transfection） was measured by ^3H-thymidine incorporation into DNA. Immunocytochemistry was used to detect the expression of proliferating cell nuclear antigen （PCNA） in tumor cells. Annexin-V and TUNEL in situ assays were used to detect apoptotic cells. The expressions of extracellular signal-regulated kinase （ERK-1/ERK-2） and somatostatin receptors （SSTR-2,SSTR-3, SSTR-5） were measured with Western blot, RESULTS; At the concentration of 1×10^-5-1×10^-9 mol/L, octreotide significantly inhibited ^3H-TdR incorporation into HepG2 cells in a dose-dependent manner （r=-0.917,P 〈 0.01） and PCNA expression, and greatly enhanced the apoptosis of HepG2 cells either in Annexin V positive rate [control vs. octrotide=（l.18±0.13）% vs. （14.20±2.57）%, P〈 0.05] or TUNEL apoptotic index [control vs.octrotide=（3.6±0.9）% vs. （18.8±3.3）%, P〈 0.05]. However, no such response happened in HepG2x cells when treated with octrotide or octrotide plus lamivudine. The expressions of SSTR-2 and SSTR-5 were significantly lower in HepG2x cells than in HepG2 cells （P 〈 0.01）; the expressions of ERK-1 and ERK-2 were significantly higher in HepG2x cells than in HepG2 cells （P〈0.05）. Octreotide didn＇t inhibit ERKs expression in HepG2 x cells.CONCLUSSION： The down-regulated expression of SSTR-2 and SSTR-5, due to HBV x gene transfection, result in decreased growth inhibitory effects ofo ctreotide on HepG2x cells.
出处
《癌症》
SCIE
CAS
CSCD
北大核心
2005年第8期965-969,共5页
Chinese Journal of Cancer
基金
国家杰出青年基金(No.39725012)~~
