摘要目的 观察Tumstatin185～191单药及联合顺铂(DDP)对肺腺癌耐药细胞株A549-DDP增殖和凋亡的影响,并探讨其联合作用的机制.方法 以不同浓度的Tumstatin185～191单药、DDP单药及Tumstatin185～191联合DDP干预A549-DDP细胞,采用四甲基偶氮唑蓝(MTT)法测定细胞的增殖情况,流式细胞术检测细胞凋亡的变化,Western blot法检测A549-DDP细胞内p-Akt和p-ERK蛋白的表达水平.结果 Tumstatin185～191对A549-DDP细胞的增殖具有抑制作用,其半数抑制浓度(IC50)为80.25 μmol/L.DDP单药对A549-DDP的IC50为77.16 μmol/L,当DDP与20 μmol/L的Tumstatin185～191联合使用时,DDP对A549-DDP细胞的IC50为57.97 μmol/L,耐药逆转指数为1.33;当DDP与40 μmol/L的Tumstatin185～191联合使用时,DDP对A549-DDP细胞的IC50为26.40 μmol/L,耐药逆转指数为2.92.两药联合使用时,A549-DDP细胞的早期凋亡率为19.5%±1.1%,较DDP单药(13.3%±1.5%)和Tumstatin185～191单药使用时的早期凋亡率(10.2%±2.0%)显著增加(F=4.09,P<0.05).Tumatatin185～191能显著抑制A549-DDP细胞内p-Akt和P-ERK蛋白的表达,但如与DDP联合使用,并不能增加Tumstatin185～191对P-ERK和p-Akt蛋白表达的抑制效应.结论 Tumstatin185～191能抑制肺腺癌耐药细胞株A549-DDP的增殖、促进凋亡,并部分逆转A549-DDP细胞对DDP的化疗耐药;其作用机制可能与Tumstatin185～191能下调A549-DDP细胞内p-Akt和p-ERK蛋白的表达有关.

abstractsObjective To investigate the effects and related mechanisms of Tumstatin 185-191 as a single agent or in combination with cisplatin on proliferation and apoptosis in a cisplatin-reslstant hnman lung edenocarcinoma cell line A549-DDP cells. Methods A549-DDP cells were treated with Tumstatin185-191 and cisplatin at varying concertrations. Cell viability was assessed by a modified 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyhetrazolium bromide (MTT) assay. 50% inhibiting concentration (IC50) values of the chemotherapeutic drugs were analyzed by MTT assay. Cell apoptosis was measured by flow cytometry. The activation of Akt and ERK was evaluated by Western blotting. Results Tumstatin185-191 inhibited the proliferation of A549-DDP cells and its IC50 value was 80.25 μmol/L. After cotreatment with 20 μmol/L Tum185-191, the IC50 value of eisplatin in A549-DDP cells reduced from 77.16 μmol/L to 57.97 μmol/L, the reverse index was 1.33, while with 40 μmol/L Tumstatin185-191 the IC50 was reduced from 77.16 to 26.40 μmol/L and the reverse index was 2.92. The early apoptosis rate was 19.5% ± 1. 1% in the cotreatment group, while 13.3% ±1.5% in cisplatin group and 10.2% ±2.0% in Tum185-191 group ( F = 4.09, P <0.05). The levels of phospho-Akt (p-Akt) and phospho-ERK (p-ERK) in the A549-DDP cells were remarkably lower after treatement with Tumstatin 185-191. The Tumstatin 185-191 treatment alone or in combination with cisplatin had a similar effect on the protein levels of p-Akt and p-ERK in A549-DDP cells. Conclusion Our data suggest that Tumstatin185-191 may promote apoptosis, downregulate proliferation and partly reverse the drug resistance of A549-DDP cells to eisplatin. The effects induced by Tum185-191 may be mediated through inactivation of the Akt and ERK pathways.