99mTc-MIBI检测肺癌耐药性的作用研究

目的拟探讨99mTc-MIBI能否检测肺腺癌A549DDP细胞的耐药性及人参单体Rh2作用后A549DDP细胞对顺铂耐药性的变化.方法用MTT法检测顺铂对敏感A549细胞和耐药A549DDP细胞的IC50、对A549DDP细胞的低效浓度(≤IC20),Rh2对A549DDP细胞的无毒浓度(≤IC5).以无毒浓度Rh2和低效浓度的顺铂联合作用于A549DDP细胞,检测Rh2对顺铂抑制A549DDP细胞的影响.以无毒浓度的Rh2单独作用于A549DDP细胞作为Rh2组,以低效浓度的顺铂单独作用于A549DDP细胞作为DDP组,以无毒浓度的Rh2和低效浓度的顺铂联合作用于A549DDP细胞作为Rh2+DDP组,以不加药物干预作为对照组,Hoechst33258染色荧光显微镜下观察细胞形态的变化,流式细胞仪检测细胞凋亡峰.γ计数器检测以上4组细胞及A549细胞的放射性活性.将以上细胞注入裸鼠皮下建模后,用99mTc-MIBI进行SPECT显像.结果順铂对A549细胞、A549DDP细胞的IC50分别为24、325 μmol/L,耐药指数为13.54.Rh2≤10 μmol/L时,对A549DDP细胞无明显毒性作用;100 μmol/L顺铂对A549DDP细胞的抑制率为12%.10 μmol/L Rh2与100 μmol/L顺铂联合作用,顺铂对A549DDP细胞的IC50降为94 μmol/L,与100 μmol/L顺铂单独作用于A549DDP细胞的IC50比,逆转3.5倍.荧光显微镜下,Rh2组和DDP组的大部分细胞核和对照组的一样,荧光分布均匀;Rh2+DDP组的荧光成团块分布,有凋亡小体形成.对照组、Rh2组和DDP组的细胞无明显凋亡峰,而Rh2+DDP组则出现了显著的凋亡峰.各组A549DDP细胞和A549细胞均能摄取99mTc-MIBI,Rh2组和DDP组与对照组之间细胞的放射性活性差异无统计学意义,而Rh2+DDP组则较对照组细胞的放射性活性显著性降低,P<0.05.A549细胞的放射性活性显著性高于A549DDP细胞的对照组,P<0.01.99mTc-MIBI 显像,A549组裸鼠可见瘤块的放射性浓聚影.A549DDP对照组和DDP组裸鼠亦可见瘤块的放射性浓聚影,其放射性浓度较A549组淡,这两组间的R或R′差异无统计学意义,但与A549组比较,P<0.05.DDP+Rh2组裸鼠无肿瘤生长,局部未见明显放射性浓聚影.结论 99mTc-MIBI能检测肺腺癌耐药的A549DDP细胞的耐药性;无毒浓度的Rh2能有效逆转A549DDP细胞对顺铂的耐药性,这种耐药性的变化亦能被99mTc-MIBI有效检测.

Examination of resistance of lung adenocarcinoma cells to cisplatin by technetium-99m methoxyisobutyl isonitrile

OBJECTIVE: To study whether technetium-99m methoxyisobutyl isonitrile ((99m)Tc-MIBI) can be used to examine the drug resistance of lung adenocarcinoma cells and to explore the efficiency of gensenoside Rh2 in reversing the resistance of adenocarcinoma cells to cisplatin (DDP). METHODS: Human lung adenocarcinoma cells of the line A549 sensitive to DDP and drug-resistant lung adenocarcinoma cells of the line A549DDP were cultured. DDP and gensenoside (Rh2) of different concentrations were added. Mthoxyisobutylisnitrile (MTT) method was used to test the inhibit concentration (IC) of DDP and Rh2 to the cells. The IC(50) of DDP to these 2 kinds of cells and its low-efficiency inhibition concentration (< or = IC(20)) to A549DDP cells, and the IC(5) of Rh2 to A549DDP cells were calculated. < or = IC20 was regarded as the low-efficiency concentration of DDP to A549DDP cells and IC(5) was regarded as the in-toxic concentration of Rh2 to A549DDP cells. A549DDP cells were divided into 4 groups: control group, added with normal saline; DDP group, added with DDP at the low-efficiency concentration; Rh2 group, added with in-toxic Rh2; and DDP + Rh2 group, added with DDP at the low-efficiency concentration and Rh2 at the in-toxic concentration. Cell apoptosis was detected by fluorescence microscopy and flow cytometry. Forty-seven hours after the stimulation by different drugs (99m)Tc-MIBI solution was added and 1 hour later the radioactivity of the cells was detected by gamma-counter. Twenty-four nude mice were divided into 4 equal groups: A549 group, inoculated with A549 cells and normal saline intraperitoneally; control group, inoculated with A549DPP cells and normal saline intraperitoneally; DDP group, inoculated with A549DDP cells and low-efficient DDP intraperitoneally; and Rh2 + DDP group, inoculated with A549DDP cells and low-efficient DDP and in-toxic Rh2intraperitoneally. The growth of tumor and survival of mice were observed. Before the inoculation of tumor cells, 4 mice were randomly selected to undergo single photons emission computed tomography (SPECT). Two months after the inoculation SPECT was performed on all mice. By the end of experiment all the mice were killed and their tumors underwent pathological examination. RESULTS: The IC(50) of DDP was 24 microM to A549 cells and 325 microM to A549DDP cells, with a resistance index of 13.54. When the concentration of Rh2 was < or = 10 microM there was no evident toxicity to A549DDP cells. The inhibition rate of 100 microM DDP to the A549DDP cells was 12%. After the cells were treated by 10 microM Rh2 and 100 microM DDP, the IC(50) of DDP to A549DDP cells was decreased to 94 microM; compared with the cells treated by 100 microM DDP alone, the reverse resistance of the latter was 3.5 times that of the former. Fluorescence microscopy showed that fluorescence was distributed uniformly in the nuclei of A549DD cells in the Rh2 group, DDP group, and the control group, and fluorescence were conglomerated like grain in the nuclei and apoptotic little substance appeared in the Rh2 + DDP group. The apoptotic rates of the control group, Rh2 group, DDP group, and DDP + Rh2 group were 6.1% +/- 1.0%, 5.9% +/- 1.1%, 8.2% +/- 1.0%, and 59.5% +/- 1.2% with a significant difference between the DDP + Rh2 group and control group (P < 0.01). There was no evident apoptotic apex in the control group, Rh2 group and DDP group, whereas there was distinct apoptotic apex in the Rh2 + DDP group. The radioactivity of (99m)Tc-MIBI could be incepted by the 4 groups. The radioactivity of the DDP + Rh2 group was significantly lower than that of the control group (P < 0.05) and there were no significant difference in radioactivity between the other 3 groups and the control group (all P > 0.05). The radioactivity of the A549 cells was significantly higher than that of the A549DDP cells (P < 0.01). Dense (99m)Tc-MIBI image of tumor could be seen in the A549 group mice, control group mice, and DDP group mice, the latter 2 groups with lighter images. No tumor image was seen in the Rh2 + DDP group mice. The R or R' value in the A549 group mice was remarkably higher than those in the control group and DDP group mice (both P < 0.05). CONCLUSION: (99m)Tc-MIBI can be used to examine the resistance of lung adenocarcinoma A549DDP cells. Gensenoside Rh2 of in-toxic concentration can reverse the resistance of lung adenocarcinoma A549DDP cells to cisplatin.