MicroRNA-32 and MicroRNA-548a Promote the Drug Sensitivity of Non-Small Cell Lung Cancer Cells to Cisplatin by Targeting ROBO1 and Inhibiting the Activation of Wnt/ß-Catenin Axis.

BACKGROUND: The roles of microRNA (miR)-32 and miR-548a in non-small cell lung cancer (NSCLC) have been studied. But their influences on NSCLC cells to cisplatin (DDP) resistance remain elusive. This study estimated the mechanisms of miR-32 and miR-548a in NSCLC cells to DDP. METHODS: Differentially expressed miRs in DDP-sensitive and resistant tissues were screened out using a GSE56036 chip. Then the predictive efficacies of miR-32 and miR-548a on DDP resistance were analyzed in NSCLC patients. The target mRNAs of miR-548a and miR-32 were predicted. miR-548a and miR-32 were knocked down to assess the influences of miR-32 and miR-548a on NSCLC growth. DDP-resistant cells were constructed and miR-32 and miR-548a expression was detected in resistant cells. After miR-32 and miR-548a knockdown, the IC50 value of DDP was detected. Then, the activation level of Wnt/ß-catenin pathway was detected. The roles of miR-32 and miR-548a in NSCLC growth in vivo were detected by tumorigenesis experiment. RESULTS: miR-32 and miR-548a were poorly expressed in DDP-resistant NSCLC. miR-32 and miR-548a mimic enhanced the DDP sensitivity of NSCLC cells. Both miR-32 and miR-548a targeted ROBO1, and overexpression of ROBO1 inhibited the promotion of miR-32 and miR-548a mimic on DDP sensitivity. ROBO1 activated the Wnt/ß-catenin pathway, thus enhancing the DDP resistance. CONCLUSION: miR-32 and miR-548a target ROBO1 and inhibit Wnt/ß-catenin activation, thus promoting the drug sensitivity of NSCLC cells to DDP.

[The clinical significance of Claudin-7 and slug expression in lung squamous cell carcinoma and adenocarcinoma].

BACKGROUND AND OBJECTIVE: The aim of this study is to investigate the expression of Claudin-7, Slug and their correltion with clinicopathological characteristics in lung squamous cell carcinoma and adenocarcinoma. We also investigated the relationship between the two factors. METHODS: The expressions of Claudin-7 and Slug in proteins were detected in 101 cases of lung squamous cell carcinoma and adenocarcinoma samples by immunohistochemistry SP method, and Western blot was applied to detect the expressions of Claudin-7 and Slug in 30 specimens of fresh lung cancer and corresponding paracancerous tissues. RESULTS: The expression of Claudin-7 was remarkably decreased in squamous cell carcinoma and adenocarcinoma tissues compared with normal lung tissue, and its expression level was closely correlated with differentiation grade and lymphatic metastasis (P<0.05), whereas the expression of Slug was significantly higher in cancer tissues than that in normal lung tissue. Outside differentiation grade and lymphatic metastasis, the expression of Slug was related to TNM stage (P<0.05). The expression of Claudin-7 was negatively correlated with the expression of Slug in lung squamous cell carcinoma and adenocarcinoma (r=-0.566,8). CONCLUSION: The down-regulation of Claudin-7 and overexpression of Slug might be one of pertinent biological markers for malignant transformation and metastasis of lung squamous cell carcinoma and adenocarcinoma.

[The Relationship between TSG101 Protein and Notch3 Receptor in Lung Cancer.].

BACKGROUND: TSG101 protein is one of the key factors in Endosomal sorting pathway. The abnormality of this pathway could decrease degradation of Notch receptor which leads to disorder of cell differentiation and development in drosophila. In mammal, the Notch3 receptors correlate with lung tissue development and lung carcinogenesis. The purpose of this study is to explore the relationship between TSG101 protein and Notch3 receptor in human lung cancer. METHODS: Immunohistochemical method (S-P method) and Western blot were applied to detect the expressions of TSG101 protein and Notch3 receptor in lung cancer tissues and cell lines, in comparison with the corresponding normal tissues and cell lines. Besides, the expression of Notch3 receptor was observed when TSG101 protein was blocked by its specific antibody. RESULTS: The TSG101 protein expressions in tumor tissues were significantly lower than those in the neighboring noncancerous tissue, with higher expressions of Notch3 receptor in tumor tissues, which were correlated with the cellular differentiation and lymph node metastases. The expression of Notch3 receptor increased after blockage of TSG101 protein by its specific antibody. CONCLUSIONS: Down-regulation of TSG101 protein was correlated with the up- regulation of Notch 3 receptor in lung cancer.

[Expression and its significance of TSG101 in lung cancer tissue and lung cancer cell lines.].

BACKGROUND: It has been proven that TSG101 is a candidate tumor suppressor gene whose deletion in NIH3T3 cells leads to spontaneous lung metastases in nude mice. Aberrant transcripts of TSG101 have been identified in primary breast carcinomas without evidence of intragenic deletions. To investigate the possible role of TSG101 and aberrant transcripts of TSG101 in lung cancer, we performed transcript analysis and protein analysis in lung cancer cell lines and lung cancer tissue. METHODS: Immunohistochemical method (S-P method) was used to detect the expression of TSG101 in 79 human squamous carcinoma and adenocarcinoma cases with the neighboring noncancerous tissue. RT-PCR was adopted to detect a common shortened TSG101 transcript because of aberrant alternative splicing and the wild-type transcript in lung cancer lines. Western Blot method was adopted to detect the expression of TSG101 protein in lung cell cells. RESULTS: The expression of TSG101 protein in tumor tissues was significantly lower than that in the neighboring noncancerous tissue. Reverse transcriptase RT-PCR analysis detected a common shortened TSG101 transcript because of aberrant alternative splicing, which was co-expressed with the wild-type transcript in seven lung cancer lines. Although shortened transcript was detected in all of lung cell cells being involved in our experiment, there is more aberrant transcipts in small cell lung cancer (SCLC) lines .Western blot analysis have detected the same differences in protein level. CONCLUSIONS: TSG101 is a candidate tumor suppressor in non small cell lung cancer. However the common TSG101 aberrant transcript may be associated with types of lung cancer, and can be used as valuable biomarkers to evaluate lung cancer poor prognosis.