Thousands of genes have been well demonstrated to play important roles in cancer progression. As genes do not function in isolation, they can be grouped into “networks” based on their interactions. In this study, we discover a network regulating Claudin-4 in gastric cancer. We observe that Claudin-4 is up-regulated in gastric cancer and is associated with poor prognosis. Claudin-4 reinforce proliferation, invasion, and EMT in AGS, HGC-27, and SGC-7901 cells, which could be reversed by miR-596 and miR-3620-3p. In addition, lncRNA-KRTAP5-AS1 and lncRNA-TUBB2A could act as competing endogenous RNAs to affect the function of Claudin-4. Our results suggest that non-coding RNAs play important roles in the regulatory network of Claudin-4. As such, non-coding RNAs should be considered as potential biomarkers and therapeutic targets against gastric cancer. Non-coding RNAs can modify the expression of proteins in cancer networks. Here the authors reveal a regulatory network in gastric cancer whereby claudin-4 expression is reduced by specific miRNAs, which are in turn bound by specific lncRNAs acting as competing endogenous RNAs (ceRNAs), resulting in increased claudin-4 expression.

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Non-coding RNAs participate in the regulatory network of CLDN4 via ceRNA mediated miRNA evasion

Long noncoding RNAs: novel insights into gastric cancer.

The epidermal growth factor receptor (EGFR) is the prototypical member of a family of membrane-associated intrinsic tyrosine kinase receptors, the ErbB family. EGFR is activated by multiple ligands, including EGF, transforming growth factor (TGF)-α, HB-EGF, betacellulin, amphiregulin, epiregulin, and epigen. EGFR is expressed in multiple organs and plays important roles in proliferation, survival, and differentiation in both development and normal physiology, as well as in pathophysiological conditions. In addition, EGFR transactivation underlies some important biologic consequences in response to many G protein-coupled receptor (GPCR) agonists. Aberrant EGFR activation is a significant factor in development and progression of multiple cancers, which has led to development of mechanism-based therapies with specific receptor antibodies and tyrosine kinase inhibitors. This review highlights the current knowledge about mechanisms and roles of EGFR in physiology and disease.

https://journals.physiology.org/doi/pdf/10.1152/physrev.00030.2015

Expression and Function of the Epidermal Growth Factor Receptor in Physiology and Disease

Long noncoding RNAs (lncRNA) participate in carcinogenesis and tumor progression in lung cancer. Here, we report the identification of a lncRNA signature associated with metastasis of non-small cell lung cancer (NSCLC). In particular, elevated expression of LINC00963 (MetaLnc9) in human NSCLC specimens correlated with poor prognosis, promoted migration and invasion of NSCLC cells in vitro, and enhanced lung metastasis formation in vivo Mechanistic investigations showed that MetaLnc9 interacted with the glycolytic kinase PGK1 and prevented its ubiquitination in NSCLC cells, leading to activation of the oncogenic AKT/mTOR signaling pathway. MetaLnc9 also interacted with P54nrb/NonO (NONO) to help mediate the activity of CRTC, a coactivator for the transcription factor CREB, reinforcing a positive feedback loop for metastasis. Taken together, our results establish MetaLnc9 as a driver of metastasis and a candidate therapeutic target for treating advanced NSCLC. Cancer Res; 77(21); 5782-94. ©2017 AACR.

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MetaLnc9 Facilitates Lung Cancer Metastasis via a PGK1-Activated AKT/mTOR Pathway.

TJs are large intercellular adhesion complexes that maintain cell polarity in normal epithelia and endothelia. During the metastatic process, TJs must be ‘loosened’ or dismantled in cancer cells to enable migration and dissemination. Diminished TJ integrity must also occur within endothelial cells to allow intravasation and extravasation of cancer cells across endothelial barriers. Claudins are critical components of TJs, forming homo- and heteromeric interactions between the adjacent cells, which have been implicated as key modulators of carcinogenesis and metastasis. Numerous epithelial-derived cancers display altered claudin expression patterns and certain claudins can now be used as biomarkers to predict patient prognosis. Moreover, claudins have been functionally implicated in numerous steps of the metastatic cascade. The distinct roles played by claudins during the cancer progression to metastatic disease are just starting to be elucidated. A more complete understanding of the mechanisms through which claudins augment cancer metastasis is required to develop new therapeutic agents against this family of proteins. In this review, we will summarize the relationship between the claudin expression and clinical outcomes in diverse cancers, discuss tumor intrinisic roles through which claudins regulate metastasis and explore claudin-mediated functions within stromal cells that influence the metastatic process. Finally, we will consider possible strategies for targeting claudins that have the potential to improve the management of metastatic cancer.

The role of claudins in cancer metastasis.

Neural precursor cell expressed, developmentally down-regulated 9 (NEDD9) is overexpressed in multiple tumor types, where it is thought to regulate tumor cell metastasis and act as a trigger of the epithelial-mesenchymal transition (EMT). Loss of E-cadherin/β-catenin and upregulation of N-cadherin are hallmarks of the EMT. The expression and correlation of NEDD9 with E-cadherin, β-catenin and N-cadherin in lung cancer are poorly characterized. We examined NEDD9, E-cadherin, β-catenin and N-cadherin protein expression in 105 cases of non-small cell lung carcinoma (NSCLC), including 43 cases of squamous cell carcinoma and 62 cases of lung adenocarcinoma, and the corresponding normal lung tissues using immunohistochemistry. NEDD9 was overexpressed in 56.2 % (59/105) of the NSCLC samples compared to normal lung tissue. Overexpression of NEDD9 correlated with abnormal expression of E-cadherin, β-catenin and N-cadherin (P < 0.001, P = 0.008 and P = 0.027, respectively). Additionally, overexpression of NEDD9 correlated positively with lymph node metastasis in NSCLC (Chi-square test; P = 0.015). The mean overall survival of NSCLC patients overexpressing NEDD9 (39.10 ± 6.49 months) was markedly shorter than patients with normal NEDD9 expression (56.67 ± 7.44 months; Log-Rank, P = 0.001). Moreover, for patients with adenocarcinoma or squarmous cell carcinoma, the survival is also dramatically poorer upon overexpression of NEDD9. In multivariate analysis, overexpression of NEDD9 (P = 0.013) and TNM stage (P = 0.001) were significant independent prognostic factors for overall survival in NSCLC. In conclusion, overexpression of NEDD9 correlates with altered expression of EMT markers, increased lymph node metastasis and poorer survival in lung cancer.

Overexpression of NEDD9 is Associated with Altered Expression of E-Cadherin, β -Catenin and N-Cadherin and Predictive of Poor Prognosis in non-Small Cell Lung Cancer

Aberrant expression of claudin proteins has been reported in a variety of cancers. Previous studies have demonstrated that overexpression of claudin may promote tumorigenesis and metastasis through increased invasion and survival of tumor cells. However, the prognostic significance of claudin-4 in gastric cancer remains unclear. Immunohistochemistry was used to analyze the expression of claudin-4 in 329 clinical gastric cancer specimens and 44 normal stomach samples, 21 intestinal metaplasia samples, and 21 adjacent precursor lesions dysplasia samples. Statistical analysis methods were used to evaluate the relationship between claudin-4 expression and various clinicopathological parameters. Univariate and multivariate analyses were performed, respectively, to detect the independent predictors of survival. Claudin-4 expression was present in only 7(15.9%) normal gastric samples, but expression of claudin-4 in the intestinal metaplasia lesions and dysplasia lesions was 90.5% and 95.2%, respectively. The expression of claudin-4 was significantly associated with histological differentiation (P < 0.001) and tumor growth patterns (P < 0.001) but not associated with patient survival. However, intermediate type staining of claudin-4 exhibited a trend of correlation with patients’ survival (P = 0.023). The five-year survival rate with low expression of claudin-4 in intermediate type (76.4%) was similar to expanding type (64.5%), while the high expression group (46.6%) was closer to infiltrative type (50.7%). The findings in this study demonstrate claudin-4 aberrant expression in gastric cancer and precursor lesions. The expression of claudin-4 could serve as a basis for identifying gastric cancer of the intermediate type.

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Clinicopathological significance of claudin-4 in gastric carcinoma

// Xiupeng Zhang 1 , Yang Liu 1 , Chuifeng Fan 1 , Liang Wang 1 , Ailin Li 2 , Haijing Zhou 1 , Lin Cai 1 , Yuan Miao 1 , Qingchang Li 1 , Xueshan Qiu 1 and Enhua Wang 1 1 Department of Pathology, Basic Medicine Science and First Hospital of China Medical University, Shenyang, China 2 Department of Radiotherapy, First Hospital of China Medical University, Shenyang, China Correspondence to: Yuan Miao, email: cmumiaoyuan@163.com Keywords: Lasp1, NSCLC, proliferation and invasion, FAK, AKT Received: December 08, 2016      Accepted: July 28, 2017      Published: August 24, 2017 ABSTRACT Lasp1 (LIM and SH3 domain protein 1) promotes tumor proliferation and invasion in multiple cancer entities including non-small cell lung cancer (NSCLC). However, the molecular mechanism is uncertain to date. In the present study, using immunohistochemistry, we found that Lasp1 expression was significantly correlated with tumor size ( P =0.005), advanced TNM stage ( P =0.042), positive regional lymph node metastasis ( P =0.034) and poor overall survival ( P 0.05). Proliferation and invasion assay showed that Lasp1 dramatically promoted the ability of proliferation and invasion of NSCLC cells. Subsequent western blot results revealed that Lasp1 promoted the expression of Cyclin A2, CyclinB1, and Snail, and inhibited the expression of E-cadherin. Lasp1 directly interacted with FAK and facilitated the expression of phosphorylated FAK (Tyr397) and AKT (Ser473). Incorporation of both FAK inhibitor and AKT inhibitor counteracted the upregulating expression of Cyclin A2, CyclinB1, and Snail, and downregulating expression of E-cadherin expression induced by Lasp1 overexpression. Interestingly, inhibition of FAK signaling pathway attenuated the phosphorylation of AKT, but inhibition of AKT signaling pathway did not affect the phosphorylation of FAK. In conclusion, Lasp1 facilitated tumor proliferation and invasion of NSCLC through directly binding to FAK and enhancing the phosphorylation of FAK (Tyr397) and AKT (Ser473). Lasp1 may be a novel therapeutic target in the treatment of NSCLC patients.

/pdf/lasp1-promotes-malignant-phenotype-of-non-small-cell-lung-2ao4dac1za.pdf

Lasp1 promotes malignant phenotype of non-small-cell lung cancer via inducing phosphorylation of FAK-AKT pathway.

ARHGEF39 promotes tumor progression via activation of Rac1/P38 MAPK/ATF2 signaling and predicts poor prognosis in non-small cell lung cancer patients.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1002/1873-3468.13461

Ailin Li

Papers

Overexpression of NEDD9 is Associated with Altered Expression of E-Cadherin, β -Catenin and N-Cadherin and Predictive of Poor Prognosis in non-Small Cell Lung Cancer

Clinicopathological significance of claudin-4 in gastric carcinoma

Lasp1 promotes malignant phenotype of non-small-cell lung cancer via inducing phosphorylation of FAK-AKT pathway.

ARHGEF39 promotes tumor progression via activation of Rac1/P38 MAPK/ATF2 signaling and predicts poor prognosis in non-small cell lung cancer patients.

Fbxo6 confers drug-sensitization to cisplatin via inhibiting the activation of Chk1 in non-small cell lung cancer.