Expression and clinical significance of RhoC and Ki-67 in human esophageal squamous cell carcinoma tissues

AIM: To investigate the expression and significance of RhoC and Ki-67 in human esophageal squamous cell carcinoma (ESCC) tissues.METHODS: The expression of RhoC and Ki-67 was detected in 52 specimens of ESCC by the method of immunohistochemistry. The clinicopathological features were also analyzed.RESULTS: The expression of RhoC was detected in 32 of the total 52 (61.5%) cases of human ESCC tissues, significantly higher than that in the adjacent histologically normal epithelium, which was only in 11 of 37 cases (29.7%, P<0.05). RhoC expression was closely correlated with clinical tumor-node-metastasis (TNM) stage (P<0.05) and lymph node metastasis (P<0.05) in ESCC. The over-expression of RhoC was positively correlated with Ki-67 in ESCC (r=0.322, P<0.05).CONCLUSION: The over-expression of RhoC protein significantly correlates with advanced TNM stage, lymph node metastasis and cell proliferation ability of ESCC. Therefore, RhoC may be a new auxiliary parameter for early diagnosis and prognostic evaluation of ESCC.     

Expression of ERK5 in colorectal cancer tissues and its correlation with distant metastasis in colorectal cancer patients

AIM: To investigate the expression of extracellular signal-regulated kinase 5 (ERK5) in primary colorectal cancer (CRC) and adjacent normal mucosa, and to analyze the relationship between ERK5 expression and clinicopathological parameters for exploring the functions of ERK5 in the occurrence and development of CRC. METHODS: The expression of ERK5 in carcinoma tissues and normal mucosa was examined by a set of tissue microarrays and the method of immunohistochemistry. The potential relationship between ERK5 expression and clinicopathological features was also analyzed. RESULTS: ERK5 expression was significantly higher in CRC tissues (134/338, 39.6%) than that in normal tissues (21/80, 26.2%; P<0.05). Overexpression of ERK5 in CRC tissues was significantly correlated with distant metastasis (P<0.05). However, no correlation between ERK5 expression and age at surgery, sex, tumor location, the depth of invasion, lymph node metastasis, TNM staging or differentiation grade was found (P>0.05). According to the Kaplan-Meier analysis, there is no significant difference in 5-year overall survival between the patients with ERK5 expression at high level and at low level. CONCLUSION: ERK5 protein is highly expressed in CRC with distant metastasis. This may be a promotive factor in the process of distant metastasis.     

Expression of SCD-1 in cervical carcinoma and effect of its down-regulation on proliferation and apoptosis of cervical carcinoma cells

AIM:To examine the expression of stearoyl-CoA desaturase-1 (SCD-1) in normal cervical tissues, cervical squamous cell carcinoma tissues, and cervical carcinoma cell lines HeLa, SiHa and CaSki, and to investigate the effect of down-regulation of SCD-1 on the proliferation and apoptosis of cervical carcinoma cells. METHODS:The expression of SCD-1 was detected by Western blotting in normal cervical tissues, cervical squamous cell carcinoma tissues, and cervical carcinoma cell lines HeLa, SiHa and CaSki. SCD-1 siRNA and control siRNA were utilized to transfect CaSki cells by Lipofectamine 2000, and SCD-1 protein level was determined by Western blotting after transfection. Furthermore, CCK-8 and flow cytometry were utilized to investigate the changes of cell proliferation and apoptosis after transfection with SCD-1 siRNA in CaSki cells. Subsequently, the activities of caspase-3 and caspase-9 were analyzed by Caspase-Glo3/7 and 9 detection kit after transfection with SCD-1 siRNA in CaSki cells. Finally, the protein expression of Bcl-2 and Bax was detected by Western blotting. RESULTS:The protein expression of SCD-1 in cervical squamous cell carcinoma tissues was significantly higher than that in normal cervical tissues, and the protein expression of SCD-1 in the 3 cervical carcinoma cell lines was obviously higher than that in normal cervical tissues, in which CaSki cells displayed the highest SCD-1 protein level. In addition, the protein expression of SCD-1 in SCD-1 siRNA group was significantly lower than that in untreated group and control siRNA group. Compared with untreated group and control siRNA group, the proliferation of CaSki cells was markedly inhibited in SCD-1 siRNA group. Early apoptotic rate in SCD-1 siRNA group was evidently higher than that in untreated group and control siRNA group. The activities of caspase-3 and caspase-9, and the level of Bax protein were significantly elevated, and the protein level of Bcl-2 was obviously reduced after transfection with SCD-1 siRNA in CaSki cells. CONCLUSION: SCD-1 may play an important role in the occurrence and development of cervical carcinoma, and its down-regulation, which mediates cell proliferation inhibition and apoptosis, may be tightly associated with the activities of caspase-3 and caspase-9, and the protein expression of Bcl-2 and Bax.     

Expression of Foxp3+ Tregs and PD1 in gastric cancer tissues and their correlation with clinicopathological factors and prognosis

AIM: To investigate the expression of Foxp3⁺ regulatory T cells (Foxp3⁺ Tregs) and programmed death receptor 1 (PD1) in gastric cancer tissues and their association with clinicopathological factors and prognosis of the patients. The correlation between the 2 molecules was also analyzed at the same time. METHODS: The tumor sections from 111 gastric cancer patients were stained for Foxp3 and PD1 by the method of immunohistochemistry. The associations of the expression levels of these 2 molecules with clinicopathological factors involved in the disease progression and prognosis were statistically analyzed. The relationship of their expression was detected. RESULTS: Foxp3⁺ Tregs and PD1 were expressed in the gastric cancer tissues, and PD1 was expressed in the tumor infiltrating lymphocytes (TILs). The expression of Foxp3 and PD1 was correlated with lymph node metastasis, clinicopathological stage and prognosis of gastric cancer patients. The expression of these 2 determinants in the patients with lymph node metastasis and an advanced clinicopathological stage was distinctly higher (P <0.05). The patients with positive expression of the 2 indexes presented a lower overall survival rate and worse prognosis (P <0.05). A significantly positive correlation between the infiltration of Foxp3⁺ Tregs and the expression of PD1⁺ TILs was also observed (P <0.01).CONCLUSION: Foxp3⁺ Tregs and PD1⁺ TILs co-infiltrate in the gastric cancer tissues, which can be used as biological markers to predict the disease progression and prognosis.     

Rab1A knockdown inhibits malignant biological behaviors of breast carcinoma cells by inhibiting phosphorylation of AKT

AIM: To investigate the role of Rab1A gene in the malignant biological behaviors of breast carcinoma cells. METHODS: The expression levels of Rab1A in breast carcinoma tissues and normal adjacent tissues, and the basic expression level of Rab1A in different breast carcinoma cell lines were measured by Western blot. Small interfering RNA (siRNA) targeting Rab1A was designed, synthetized and transfected into the breast carcinoma MDA-MB-231 cells. After validation of efficiency of Rab1A gene expression knock-down, the malignant biological behaviors of the MDA-MB-231 cells were measured by CCK-8 assay, wound healing assay, Transwell assay and flow cytometry. The protein levels were determined by Western blot. RESULTS: Rab1A was expressed in normal breast tissue and cells at low level, and at high level in the cancer tissues and cancer cells (P<0.05). Compare with control group, after knock-down of Rab1A expression, the viability of MDA-MB-231 cells was significantly inhibited (P<005), the abilities of migration and invasion were reduced (P<0.05), the apoptosis was decreased (P<0.05), the percentage of G²/M phase was increased, the protein levels of p53, Bax, cleaved caspase-3 and PTEN were significantly increased (P<0.05), and the protein levels of Bcl-2, cyclin D1, cyclin B1, matrix metalloproteinase 2 (MMP2), p-AKT and mTOR were significantly decreased (P<0.05). CONCLUSION: Rab1A modulates the breast carcinoma cell viability, inhibits the migration and invasion abilities, induces G² arrest and effectively regulates the cell growth-, cell cycle-and apoptosis-related proteins. Knock-down of Rab1A expression inhibits the evolution and development of breast cancer by inhibiting the phosphorylation of AKT pathway, and Rab1A may function as a potential target in breast carcinoma treatment.     

Effects of down-regulation of AEG-1 expression on cell cycle and invasion of human cervical carcinoma cells

AIM: To investigate the effects of down-regulation of astrocyte elevated gene-1 (AEG-1) expression on cell cycle and invasion of human cervical carcinoma SiHa cells.METHODS: The protein expression of AEG-1 was detected by Western blotting in normal cervical tissues, cervical squamous cell carcinoma tissues, HeLa cells, SiHa cells and CaSki cells. Control siRNA or AEG-1 siRNA was transfected into SiHa cells, and the protein expression of AEG-1 in SiHa cells was detected by Western blotting. The changes of cell cycle distribution and cell invasion were determined by flow cytometry and Boyden chamber, respectively. The protein levels of cyclin D1, cyclin-dependent kinase 2(CDK2) and matrix metalloproteinase-9 (MMP-9) were analyzed by Western blotting.RESULTS: The protein expression of AEG-1 in cervical squamous cell carcinoma tissues was significantly higher than that in normal cervical tissues (P<0.05). Meanwhile, the protein expression of AEG-1 in the 3 cervical carcinoma cell lines was obviously higher than that in normal cervical tissues, in which SiHa cells displayed the highest AEG-1 protein level (P<0.05). In addition, AEG-1 siRNA effectively down-regulated the protein expression of AEG-1 in SiHa cells, which led to increase the percentage at G0/G1 phase and reduced the invasion of SiHa cells. Furthermore, the protein levels of cyclin D1, CDK2 and MMP-9 in AEG-1 siRNA group were markedly lower than those in non-treatment group and control siRNA group (P<0.05).CONCLUSION: Over-expression of AEG-1 may be closely associated with the occurrence and development of cervical carcinoma, and the AEG-1 down-regulation-mediated cell cycle arrest and attenuation of invasion may be tightly related to the down-regulations of cyclin D1, CDK2 and MMP-9 at protein levels.     

ACTL8 expression and its correlation with clinicopathological features and prognosis in breast cancer

AIM: To investigate the actin-like protein 8 (ACTL8) expression and its relationship with clinicopathological features and prognosis in breast cancer.METHODS: The expression of ACTL8 in human normal mammary epithelial cell line MCF-10A and 5 breast cancer cell lines was detected by Western blot. The expression of ACTL8 was also investigated by immunohistochemistry in 6 cases of breast cancer specimens with adjacent normal tissues. The data in 488 cases of breast specimens from TCGA dataset were downloaded, and the relationship between the mRNA expression of ACTL8 and the clinicopathological features and prognosis was analyzed.RESULTS: The expression of ACTL8 in 4 breast cancer cell lines was significantly higher than that in breast epithelial cell line MCF-10A.The level of the ACTL8 expression in breast tumors was significantly higher than that in the corresponding adjacent normal breast tissues. The mRNA expression of ACTL8 was correlated with age, tumor size, clinical TNM stage and lymph node metastasis of breast cancer patients (P < 0.05). The high expression level of ACTL8 mRNA indicated a poor prognosis of breast cancer patients. CONCLUSION: ACTL8 protein is highly expressed in breast cancer specimens and is closely correlated with the clinicopathological features and prognosis, suggesting that ACTL8 is a prognostic marker for breast cancer or a potential new target for treatment of breast cancer.     

Changes of nitric oxide synthase and nitric oxide in lung of smoking rats

AIM:To observe the changes of iNOS and eNOS in lung tissue and NO in bronchoalveolar lavage fluid (BALF) in smoking rats.METHODS:80 Wistar rats were divided into control, smoking group, L-NIL group and L-NAME group (rats were exposed to smoke and injected (i.p.) with selective iNOS inhibitor L-NIL or NOS inhibitor L-NAME). iNOS and eNOS protein levels in whole lung were detected by immunohistochemical staining, and NOS mRNA was quantified using RT-PCR. In addition, NO₂^-/NO₃^- was determined using Griess assay.RESULTS:The expression of iNOS mRNA and protein in smoking rats increased, the expression of eNOS mRNA and eNOS protein decreased, and the total cell count and the level of NO₂^-/NO₃^-in BALF increased(P＜0.05). In vivo, L-NIL reduced the total cell count and NO₂^-/NO₃^- in BALF (P＜0.05), while L-NAME had no effect on them.CONCLUSION:Cigarette smoke increased expression of iNOS mRNA and protein and decreased expression of eNOS mRNA and protein. The large amount of NO generated by iNOS may amplify inflammation in lung tissue.     

Expression of HDAC6 protein in cervical carcinoma tissues and its clinical significance

AIM:To investigate the protein expression of histone deacetylase 6(HDAC6) in cervical carcinoma tissues and its clinical value. METHODS:The method of immunohistochemistry was used to detect the protein expression of HDAC6 in 63 cases of cervical carcinoma tissues, 38 cases of cervical intraepithelial neoplasia(CIN) tissues and 63 cases of normal cervical epithelial tissues. The relationships between the protein expression of HDAC6 and clinical pathological features were analyzed. The protein expression of HDAC6 in randomly selected 4 cases of cervical carcinoma tissues and paired normal cervical epithelial tissues was detected by Western blotting. RESULTS:Positive rates of HDAC6 protein expression in cervical carcinoma tissues were significantly higher than that in CIN tissues or normal cervical epithelial tissues, and there were obvious differences among the 3 groups(P<0.05). The protein expression of HDAC6 was not related to age and histological differentiation(P>0.05), but closely associated with clinical stages, invasive depth and lymph node metastasis(P<0.01 or P<0.05). Furthermore, the result of Western blotting demonstrated that the protein level of HDAC6 in cervical carcinoma tissues was markedly higher than that in normal cervical epithelial tissues. CONCLUSION:HDAC6 may be an important molecular marker for evaluating malignant degree and prognosis of cervical carcinoma.     

Study of annexin A2 expression in gastric cancer by proteomics and tissue microarray

AIM: To investigate the differential expression of annexin A2 (ANXA2) in gastric carcinoma and to analyze the relationship between ANXA2 expression and clinicopathological parameters of gastric carcinoma. METHODS: Pure gastric adenocarcinoma cells (GAC) and normal gastric epithelial cells (NGEC) in 15 patients with gastric cancer were acquired by laser capture microdissection (LCM). All peptide specimens after trypsin digestion were labeled with ¹⁸O/¹⁶O. Quantitatively identification of differential expression of the proteins betweem GAC and NGEC was performed by Nano-RPLC-MS/MS. The expression of ANXA2 in the 2 kinds of tissues was detected by Western blotting. Tissue microarray containing 75 pairs of gastric carcinoma and para-carcinoma tissues was used and the expression of ANXA2 in these specimens was detected by the method of immunohistochemistry (IHC). The relationship between ANXA2 expression and clinicopathological parameters of the pateints with gastric carcinoma was analyzed. RESULTS: A total of 78 differential proteins were identified and ANXA2 was up-expressed in GAC (2.32∶ 1), which was confirmed by Western blotting (P<0.01). The results of IHC showed that the correlations between the expression level of ANXA2 protein and invasive depth (T stage), lymph node metastasis (N stage), histological differentiation, TNM stage and the size of tumor were observed (P<0.01), but the correlations between the ANXA2 expression and sex, age and distant metastasis (M stage) were not found (P>0.05). CONCLUSION: The up-expressed ANXA2 may play an important role in the biological behavior of gastric cancer.     

The molecular mechanism of inhibition of murine Lewis lung carcinoma metastasis by weimaining in vivo

AIM: To investigate the anti-metastasis effect of weimaining, extracted from fragopyrum cymosum meissn, a Chinese medicine, on murine Lewis lung carcinoma (3LL). METHODS: The anti-metastasis effect of weimaining in vivo was detected in the grafting lung metastasis model of murine Lewis lung carcinoma. The effects of the drug on the expression of CD34 and E-cadherin were investigated by immunohistochemical staining and RT-PCR. RESULTS: Weimaining effectively inhibited the lung metastasis of 3LL at a concentration of 250 mg·kg^-1·d^-1, significantly suppressed the expression of CD34 and increased the expression levels of E-cadherin protein and mRNA in 3LL cells. CONCLUSIONS: Weimaining inhibits the metastasis of murine Lewis lung carcinoma (3LL) in vivo via increasing the expression of E-cadherin and decreasing microvessel density of tumor tissue.     

Expression of miR-203 in human tongue carcinoma tissues and its in-fluence on viability and invasion ability of Tca8113 cells

AIM: To study the expression of miR-203 in tongue carcinoma tissues and the effect of miR-203 over-expression on the viability and invasion ability of Tca8113 cells.METHODS: Twenty-eight pairs of tongue carcinoma tissues and adjacent nontumor tissues were collected, and the clinicopathological characters were analyzed. miR-203 was detected in the tongue tissues of 28 patients with tongue carcinoma by real-time PCR. miR-203 mimics and scramble were transfected into Tca8113 cells by Lipofectamine 2000. The expression of miR-203 was detected in Tca8113, Tca8113-miR-203 mimics and Tca8113-scramble cells by RT-qPCR. The cell viability was measured by CCK-8 assay. The cell invasion ability was determined by Transwell chamber invasion experiment.RESULTS: miR-203 expression was significantly down-regulated in the tongue carcinoma tissues compared with those in the adjacent nontumor tissues. The expression of miR-203 was associated with TNM stage and lymph node metastasis. Up-regulation of miR-203 inhibited the viability and invasion ability of Tca8113 cells.CONCLUSION: miR-203 suppresses the growth and invasion of tongue carcinoma cells. miR-203 may be a potential therapeutic target for treating human tongue cancer.     

Effects of ZIP14 on biological behaviors of hepatocellular carcinoma cell line BEL-7404

AIM: To study the expression of zinc transporter ZRT/IRT-like protein 14 (ZIP14) in the hepatocellular carcinoma (HCC) tissues, and to investigate the effects of ZIP14 over-expression on the biological behaviors of HCC cells. METHODS: The expression of ZIP14 at mRNA and protein levels in the HCC tissues and adjacent non-tumor tissues were detected by real-time PCR and immunohistochemical staining, respectively. The lentivirus expression system containing GV365-ZIP14 was constructed, and was used to infect the HCC cell line BEL-7404, which had relatively poor expression of ZIP14. The expression of ZIP14 at mRNA and protein levels in the transfected cells were detected by real-time PCR and Western blot, respectively. Under the conditions of zinc sulfate stimulation at different concentrations, the cell viability, the cell cycle, and the cell migration and invasion abilities were detected by MTT assay, DNA ploid detection, and Transwell assay, respectively. RESULTS: The mRNA expression level and the strong-positive rate of protein expression of ZIP14 in the HCC tissues were significantly lower than those in the adjacent non-tumor liver tissues (P<0.01). The expression of ZIP14 at mRNA and protein levels in the BEL7404 cells was significantly enhanced by infection of GV365-ZIP14 expression lentivirus. Compared with negative control group (transfected with negative control lentivirus), the cell viability, migration and invasion in ZIP14 over-expression group (transfected with GV365-ZIP14 expression lentivirus) were significantly reduced, and the percentage of the cells in G₂/M phase was significantly increased, all of which were more obvious with the elevation of zinc concentration in the culture medium. CONCLUSION: ZIP14 is low expressed in the HCC tissues. The ZIP14 over-expression has inhibitory effects on the viability, migration and invasion of HCC cells, and blocks the cell cycle in G₂/M phase, which might be closely related to the elevation of zinc concentration in cytoplasma of HCC cells due to enchanced zinc transport by ZIP14.     

Differential expression of Golgi mannosidaseⅡ in different differentiated gastric carcinoma cell lines and tissues

AIM: To explore the role of Golgi mannosidase Ⅱ(GMⅡ) in the development of gastric carcinoma by analysis of the relationship between differential expression of GMⅡ and differentiation of gastric carcinoma cell lines and tissues. METHODS: Thirty cases of human normal gastric tissues and 38 cases of gastric adenocarcinoma tissues were selected. Three different differentiated gastric carcinoma cell lines (MKN-28, SGC-7901 and BGC-823) and a normal gastric epithelial cell line GES-1 were cultured in vitro. The mRNA levels of GMⅡ were detected by RT-PCR, and the protein expression was detected by immunohistochemistry and Western blotting. RESULTS: GMⅡ was mainly distributed in cytoplasm. The positive rates of GMⅡ in 30 cases of human normal gastric tissues, 8 cases of well-differentiated, 18 cases of moderately-differentiated and 12 cases of poorly-differentiated gastric cancer tissues were 53% (16/30), 63% (5/8), 83% (15/18) and 100% (12/12), respectively. The expression of GMⅡ was gradually increased in normal gastric epithelial cell line and in well, moderately and poorly-differentiated gastric cancer cell lines by cell-attached coverslip. Compared with normal gastric epithelial cell line, 3 gastric carcinoma cell lines showed the higher expression of GMⅡ at mRNA and protein levels (P<0.05). Furthermore, GMⅡ expression in poorly-differentiated gastric carcinoma cell line BGC823 was the highest, and the lowest expression of GMⅡ was the well-differentiated cell line MKN-28. Compared with normal gastric epithelial tissues, gastric carcinoma tissues showed the higher expression of GMⅡ at mRNA and protein levels (P<0.05), and the highest was the poorly-differentiated carcinoma tissues. The expression of GMⅡ at mRNA and protein levels in normal gastric tissues was the lowest. CONCLUSION: GMⅡ is involved in the development and progression of gastric cancer. The expression of GMⅡ is highly related to the poorly-differentiated gastric cancer.     

Relationship between FRAS1 protein and brain metastases of NSCLC

AIM: To explore the relationship between FRAS1 protein and brain metastases of non-small cell lung cancer (NSCLC).METHODS: The mRNA expression of FRAS1 in the brain metastatic tumor tissues and primary tumor tissues of NSCLC was detected by qPCR. The protein expression of FRAS1 in the tumor tissues and normal tissues adjacent to tumor tissues of NSCLC was measured by SP method of immunohistochemistry. The protein expression of FRAS1 in NSCLC primary tumor tissues with or without brain metastases was also determined.RESULTS: The mRNA expression of FRAS1 in the brain metastatic zone was nearly 10 times higher than that in the primary tumor tissues, and there was significant difference between the 2 groups (P<0.05). FRAS1 protein was expressed in the NSCLC primary tumor tissues, but was not found in the normal tissues adjacent to primary tumor tissues. The protein expression of FRAS1 in the NSCLC with brain metastases was significantly higher than that without brain metastases (P<0.01).CONCLUSION: FRAS1 protein may be associated with the occurrence of NSCLC. The over-expression of FRAS1 protein may be related to brain metastases with NSCLC.     

Differentiated expression of myosin VI in diverse human carcinomas

AIM: To investigate the expression profile of myosin VI in various human carcinomas and adjacent normal tissues. METHODS: A piece of cancer profiling array containing 154 matched cDNA pairs from 19 tumors and the adjacent normal tissues and 10 diverse tumor cell lines were separately hybridized with radiolabeled probes for myosin VI and housekeeping gene ubiquitin. Immunohistochemistry (IHC) was used to confirm the expression profile of myosin VI in 40 cases of ovarian adjacent normal tissues, 8 cases of cystadenoma, 16 cases of borderline tumors and 52 cases of endometrioid carcinoma by tissue microarray. RESULTS: Myosin VI was expressed in all the tissues and cell lines. The expression of myosin VI was significantly higher in ovarian and colon cancer tissues than that in matched normal tissues. The results of IHC confirmed that myosin VI expression rates were 100% (52/52), 81.3% (13/16) and 10.4% (5/48) in the ovarain carcinoma, boderline tumor and nomal ovarian epithelium or cystadenoma, respectively. The expression of myosin VI protein was significantly higher and stronger in ovarain carcinoma than that in the borderline tumor, benign tumor or normal ovary tissues. A significant correlation was also found between the expression of myosin VI and the tumor grade of ovarain carcinoma. CONCLUSION: Differentiated expression of myosin VI is found in diverse malignant tumor tissues and cell lines, suggesting myosin VI plays an important role in the tumor development and progression.     

NET-1 promotes metastasis of lung squamous-cell carcinoma by activating EMT

AIM: To explore the effect of neuroepithelial cell transforming gene-1 (NET-1) expression on the metastasis of lung squamous-cell carcinoma (LSC) and the underlying molecular mechanism. METHODS: Immunohistochemistry was used to detect the expression of NET-1 protein in 53 cases of lung squamous-cell carcinoma (LSC group), 24 cases of normal lung epithelium (NLE group) and 27 cases of lung squamous intraepithelial lesions (SIL group). The correlation of clinical and pathological factors was analyzed. The protein expression of NET-1 in human lung squamous-cell carcinoma cell lines H226, H1703, H2170, SK-MES-1, H520 and YTMLC-90 was determined by Western blot. The RNA interference recombinant adenovirus against NET-1 gene (Ad-NET-siRNA) and Ad-control with control sequence were constructed and infected with human lung squamous cell carcinoma cell YTMLC-90 to silence the expression of NET-1 gene. The protein expression of NET-1, E-cadherin, vimentin and Snail1 in the BEAS-2B cells and the YTMLC-90 cells was determined by Western blot. The mRNA expression of E-cadherin and vimentin in each group of the cells was detected by qPCR. The invasive ability of the cells in each group was detected by Transwell chamber assay. RESULTS: The positive expression rate of NET-1 in LSC group was significantly higher than that in NLE group and SIL group(P<0.05). The distribution of NET-1 protein positive expression population was correlated with histological grade, lymph node metastasis, and TNM stage. The NET-1 expression rate of LSC with lymph node metastasis was significantly higher than that without lymph node metastasis. Over-expression of NET-1 protein in YTMLC-90 cells was observed. The expression of E-cadherin was decreased, and the protein expression of vimentin and Snail1 was increased in YTMLC-90 cells. Knock-down of NET-1 expression increased the expression of E-cadherin, and decreased the expression of vimentin and Snail1 in the YTMLC-90 cells. CONCLUSION: The expression of NET-1 promotes the lymphatic metastasis of lung squamous-cell carcinoma. This promotion may be achieved through the activation of epithelial-mesenchymal transition (EMT) by NET-1 expression.