Effects of claudin-1 downregulation on the physiological processes of gallbladder cancer SGC996 cells

Long non-coding RNA VPS9D1-AS1 promotes growth of colon adenocarcinoma by sponging miR-1301-3p and CLDN1

Colon adenocarcinoma is a frequent malignancy among all colon cancer types. Long non-coding RNAs (lncRNAs) are involved in the progression of colon adenocarcinoma. This study aimed to uncover the molecular mechanism of VPS9D1-AS1 in regulating colon adenocarcinoma development. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR) revealed that VPS9D1-AS1 expression was markedly upregulated in colon adenocarcinoma tissues and cell lines. Cell functional experiments showed that knockdown of VPS9D1-AS1 repressed the growth and invasion of colon adenocarcinoma cells but upregulated cell apoptosis. In addition, we confirmed the interaction of VPS9D1-AS1-miR-1301-3p-CLDN1 using a luciferase assay. Downregulation of miR-1301-3p promoted the progression of colon adenocarcinoma cells. In conclusion, VPS9D1-AS1 facilitated cell growth and suppressed apoptosis of colon adenocarcinoma cells by sponging miR-1301-3p and upregulating CLDN1, which may be effective therapeutic strategies for patients with colon adenocarcinoma.

Claudin-1 Is a Valuable Prognostic Biomarker in Colorectal Cancer: A Meta-Analysis

Background

Claudin-1 plays an important part in maintaining the mucosal structures and physiological functions. Several studies showed a relationship between claudin-1 and colorectal cancer (CRC), but its prognostic significance is inconsistent. This meta-analysis assessed the prognostic value and clinical significance of claudin-1 in CRC.

Materials and Methods

We retrieved eligible studies from PubMed, Cochrane Library, Embase, and Web of Science databases before February 10, 2020. The hazard ratio (HR) with 95% confidence interval (CI) was applied to assess the correlation between claudin-1 and prognosis and clinical features. Heterogeneity was assessed by the Cochran Q test and I-square (I²), while publication bias was evaluated by the Begg test and Egger test. Test sequence analysis (TSA) was used to estimate whether the included studies' number is sufficient. The stability of the results was judged by sensitivity analysis. Metaregression was utilized to explore the possible covariance which may impact on heterogeneity among studies.

Results

Eight studies incorporating 1704 patients met the inclusion criteria. Meta-analysis showed that the high expression of claudin-1 was associated with better overall survival (HR, 0.46; 95% CI, 0.28–0.76; P = 0.002) and disease-free survival (HR, 0.44; 95% CI, 0.29–0.65; P = 0.003) in CRC. In addition, we found that claudin-1 was related to the better tumor type (n = 6; RR, 0.60; 95% CI, 0.49–0.73; P < 0.00001), negative venous invasion (n = 4; RR, 0.81; 95% CI, 0.70–0.95; P = 0.001), and negative lymphatic invasion (n = 4; RR, 0.83; 95% CI, 0.74–0.92; P = 0.0009).

Conclusion

The increased claudin-1 expression in CRC is associated with better prognosis. In addition, claudin-1 was related to the better tumor type and the less venous invasion and lymphatic invasion.

Upregulation of COL8A1 indicates poor prognosis across human cancer types and promotes the proliferation of gastric cancer cells

Gastric cancer (GC) was one of the most common types of the digestive system. COL8A1 was reported to be associated with cancer progression. The present study showed COL8A1 was overexpressed and correlated to shorter overall survival (OS) time across human cancer types. Specially, our results showed COL8A1 was up-regulated in advanced stage GC compared to low stage GC samples. Higher expression of COL8A1 was significantly correlated to shorter OS time in patients with GC. Bioinformatics analysis revealed COL8A1 was involved in regulating cell proliferation and metastasis. Experimental validations of COL8A1 showed that silencing of COL8A1 could significantly suppressed cell proliferation, migration and invasion in GC. These results provided a potential target for the clinical prognosis and treatment of gastric cancer.

Sulforaphane metabolites inhibit migration and invasion via microtubule-mediated Claudins dysfunction or inhibition of autolysosome formation in human non-small cell lung cancer cells

Both sulforaphane-cysteine (SFN-Cys) and sulforaphane-N-acetyl-l-cysteine (SFN-NAC) inhibited cancer migration and invasion, but the underlying mechanisms were not clear. Here we uncovered via tissue microarray assay that high expression of invasion-associated Claudin-5 was correlated to malignant grades in human non-small cell lung cancer (NSCLC) cells. Further, SFN-Cys (10 µM) induced the accumulated phosphorylation of ERK1/2, leading to downregulation of Claudin-5 and upregulation of Claudin-7, and the decrease of Claudin-1 in SK-1 cells and increase of Claudin-1 in A549 cells; knockdown of Claudin-5 significantly reduced invasion, whereas knockdown of Claudin-7 increased invasion; knockdown of Claudin-1 reduced invasion in SK-1 cells, whereas it increased invasion in A549 cells, indicating that SFN-Cys regulated Claudins and inhibited invasion depending on Claudin isotypes and cell types. Furthermore, immunofluorescence staining showed that SFN-Cys triggered microtubule disruption and knockdown of α-tubulin downregulated Claudin-1, 5, and 7, and inhibited migration and invasion, indicating that microtubule disruption contributed to invasive inhibition. Co-immunoprecipitation and confocal microscopy observation showed that SFN-Cys lowered the interaction between α-tubulin and Claudin-1 or 5, or 7. Meanwhile, Western blotting and immunofluorescence staining showed that SFN-NAC (15 µM) downregulated α-tubulin resulting in microtubule disruption; knockdown of α-tubulin increased SFN-NAC-induced LC3 II accumulation in SK-1 cells. Combined with the inhibitor of autolysosome formation, Bafilomycin A1 (100 nM), SFN-NAC inhibited invasion via accumulating LC3 II and blocking formation of autolysosome. Further, SFN-NAC upregulated microtubule-stabilizing protein Tau; knockdown of Tau reduced LC3 II/LC3 I inhibiting migration and invasion. These results indicated that SFN-Cys inhibited invasion via microtubule-mediated Claudins dysfunction, but SFN-NAC inhibited invasion via microtubule-mediated inhibition of autolysosome formation in human NSCLC cells.