Comparative Proteome Analysis Between Primary Tumor And Lymph-node Metastatic Tumor In Human Lung Squamous Carcinoma

Nowadays,lung cancer has become one of the most malignanttumors with the highest incidence and mortality.As a grand disease whichis threatening the whole human society, lung cancer is the leading cause ofcancer deaths,accouting for 17.6% of all cancer deaths worldwide,and hasa low five-year survival rate(8.9%～15%)o Because of the non-specificnature of its clinical symptoms,most of the patients diagnosed as havinglung cancer eventually died of widespread metastasis.Tumor invasion andmetastasis is not only the malignant characteristics of lung cancer, but alsothe chief cause of failure to cure and high mortality.Lung squamouscarcinoma is the most common type and it accounts for 30%～50% in alltypes of lung cancer.Metastasis of lung squamous carcinoma is a comple-x process involving multiple events and steps.Though some molecularstudies on human lung cancer have been undertaken successfully on thegene(DNA) AND transcription(mRNA) levels, it remains unclear thathow lung cancer cells give rise to metastasis. Furthermore,the executionmolecules are proteins,but not DNA or mRNA.Thus,the proteomics appr-oach may directly and comprehensively explore the metastatic mechanis-m of lung cancer.For the reason of obtaining the pure cacer cells,LCM was performedto select and collect cancer cells from primary tumor and lymph-nodemetastatic tumor in human squamous carcinoma with highpurity.Comparative two-dimensional gel electrophoresis(2-DE)technology was performed to separate the total protein of primary tumorand lymph-node metastatic tumor in human squamous carcinomacollected by LCM.The well-resolved,reproducible 2-DE patterns wereestablished.Then,PDQuest software was used to analyze 2-DEimages,and 22 proteins with differential expressions were identified by both peptide mass fingerprint(PMF) and peptide sequence tag(PST) basedon MALDI-TOF-MS (Matrix-assisted laser desorption/ionization timeof flight mass spectrometry) and ESI-Q-TOF-MS (Electrosprayionization-quadrupole time of flight mass spectrometry).In order tovalidate the reliability of the identified results,the expressions of twoproteins,Rho-GDI alpha and stratifin,were detected byimmunohistochemical staining and western blot analysis.The results areconsistent with the proteome analysis results.In this study, the combination of LCM with 2-DE and massspectrometry was used to establish well-resolved,reproducible 2-DEpatterns of primary cancer and lymph-node metastatic tumor in humansquamous carcinoma and characterize 22 differential expression proteins.Most of the candidates have been suggested to play role in cellgrowth,migration,movement,adhesion,apoptosis,or metabolism etc,thusmaybe influencing the metastasis potency of tumor cells. These resultsare valuable for further study of the invasion and metastasis mechanismsof lung cancer, as well as to evaluate the patients' prognosis and providenew clues for treatment target。...