The role of cytochrome c oxidase subunit Va in nonsmall cell lung carcinoma cells: association with migration, invasion and prediction of distant metastasis Full Text
BMC Cancer, 07/05/2012
Chen W-L et al. – Our current study showed that COX Va may play a role in migration and invasion of NSCLC cells and can be used as a biomarker to predict aggressiveness of NSCLC.Methods
- We classified four NSCLC cell lines into high and low migration/invasion groups by Transwell and Matrigel assays.
- Using two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), we identified 10 membrane-associated proteins being significantly overexpressed in the high migration/invasion group.
- The expression of the target protein in the four NSCLC cell lines was then confirmed by reverse transcription polymerase chain reaction (RT-PCR), western blot and immunostaining.
- RNA interference technique was applied to observe the influence of the target protein on migration and invasion.
- Gelatin zymography was also performed to evaluate the activities of matrix metalloproteinase (MMP)-2 and MMP-9.
- Expression condition of the target protein on surgical specimens was further examined by immunohistochemical staining and the clinicopathologic data were analyzed.
- We identified a mitochondria-bound protein cytochrome c oxidase subunit Va (COX Va) because of its abundant presence found exclusively in tumorous areas.
- We also demonstrated that migration and invasion of NSCLC cells decreased substantially after knocking down COX Va by siRNA.
- Meanwhile, we found a positive correlation between COX Va expression, Bcl-2 expression and activities of MMP-2 and MMP-9 in NSCLC cells.
- Immunohistochemical staining of surgically resected lung adenocarcinomas in 250 consecutive patients revealed that strong COX Va expression was found in 54.8% (137/250) of patients and correlated positively with the status of lymph node metastasis (P=0.032).
- Furthermore, strong COX Va expression was associated with the presence of distant metastasis (P=0.033).