厄洛替尼对MKN45细胞株放射增敏机制的实验研究

目的观察厄洛替尼联合放射线对MKN45细胞的影响，初步探讨厄洛替尼对其放射增敏机制。方法通过MTT法检测厄洛替尼、5-氟尿嘧啶（5-Fu）对MKN45细胞的生长抑制作用，流式细胞仪检测MKN45细胞经厄洛替尼、5-Fu及联合放射线处理后细胞的7周亡率及周期分布情况；WesternBlots法检测厄洛替尼、5-Fu及联合放射线对MKN45细胞的Bax与Bcl-2蛋白表达的影响。结果厄洛替尼、5-Fu均能抑制MKN45细胞的生长，与药物浓度及作用时间呈正相关（P〈0．01）。厄洛替尼联合组使G2／M、G0／G1期细胞比率增加最明显，与5-Fu联合组比较有统计学意义（70．32±0．65vs58．25±0．42，P〈0．01）；细胞凋亡率增加最多，与5-Fu联合组比较有统计学意义（19．21±1_23 vs 13．11±0．76，P〈0．01）；厄洛替尼联合组作用于细胞后，Bcl-2蛋白表达明显减少，Bax蛋白表达则明显增加，与其他组比较差异显著（P〈0．01）。结论厄洛替尼的放射增敏机制与增加MKN45细胞的细胞凋亡率、G2／M和GO／G1期细胞比率；降低Bcl-2、升高Bax蛋白表达，从而降低Bcl-2／Bax比率有关。

Obseruation of effect of erlotinib on radiosensitization mechanism of MKN45 cell lines

Obioctivo To observe the effect of erlotinib combined with radiotherapy on MKN45 cells so as to detect the mechanism of erlotinib in increasing the sensitivity ot7 radiotherapy. Methods The effect of erlotinib and 5-fluorouracil （5-Fu）on MKN45 cells was determined by MTT method. Cell apoptosis rate and distribution at cell phase of MKN45 cells after treated with erlotinib, 5-Fu and radiation were assayed by flow cytometry. The expression of bcl-2 and bax protein of MKN45 cells treated with erlotinib,5-Fu and radiation was determined by Western Blot method. Rosults Erlofinib and 5-Fu could inhibit MKN45 cell growth and the inhibition enhanced significantly along with the increase of drug concentration and time.（P〈0.01 ）. G2/M and G0/G1 phase cells increased significantly when the cells were treated with erlotinib and radiation combination, compared to that treated with 5-Fu combined with radiation group （70.32±0.65vs58.25 ± 0.42,P〈0.01 ）,Cell apoptosis also increased obviously compared to 5-Fu combined with radiation group （19.21± 1.23vs13.11 ± 0.76,P〈0.01 ）. After treated with erlotinib and radiation,Bel-2 protein expression decreased while Bax protein expression increased compared to the other group with significant difference （P〈0.01）.Conclusions Erlotinib can increase MKN45 cell radiosensitivity by increasing G2/M and G0/G1 cell ratio, decreasing Bcl-2 protein expression and increasing Bax protein expression.