[Tumstatin185-191 increases the sensitivity to cisplatin in a cisplatin-resistant human lung adenocarcinoma cell line].
OBJECTIVE
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-resistant human lung adenocarcinoma cell line A549-DDP cells.


METHODS
A549-DDP cells were treated with Tumstatin185-191 and cisplatin at varying concentrations. Cell viability was assessed by a modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. 50% inhibiting concentration (IC(50)) 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 IC(50) value was 80.25 micromol/L. After cotreatment with 20 micromol/L Tum185-191, the IC(50) value of cisplatin in A549-DDP cells reduced from 77.16 micromol/L to 57.97 micromol/L, the reverse index was 1.33, while with 40 micromol/L Tumstatin185-191 the IC(50) was reduced from 77.16 to 26.40 micromol/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 treatment 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.


CONCLUSIONS
Our data suggest that Tumstatin185-191 may promote apoptosis, downregulate proliferation and partly reverse the drug resistance of A549-DDP cells to cisplatin. The effects induced by Tum185-191 may be mediated through inactivation of the Akt and ERK pathways.
Wang
Wei
W
Department of Respiratory Medicine, the Second Xiangya Hospital, Central South University, Changsha 410011, China.
Chen
Ping
P
Li
Jun-li
JL
Pei
Yan-fang
YF
Shuang
Qing-cui
QC
Liu
Cai-Hong
CH
Cai
Shan
S
Liu
Shao-kun
SK
Zhu
Lan-yan
LY
Zhou
Rui
R
D000230:Adenocarcinoma / Q000473:pathology*; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001324:Autoantigens / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002945:Cisplatin / Q000494:pharmacology; D024141:Collagen Type IV / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D010446:Peptide Fragments / Q000494:pharmacology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
D000970:Antineoplastic Agents; D001324:Autoantigens; D024141:Collagen Type IV; D010446:Peptide Fragments; C057112:type IV collagen alpha3 chain; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D002945:Cisplatin