4015

LOX

Hypoxia has been shown to promote tumor metastasis and lead to therapy resistance. Recent work has demonstrated that hypoxia represses E-cadherin expression, a hallmark of epithelial to mesenchymal transition, which is believed to amplify tumor aggressiveness. The molecular mechanism of E-cadherin repression is unknown, yet lysyl oxidases have been implicated to be involved. Gene expression of lysyl oxidase (LOX) and the related LOX-like 2 (LOXL2) is strongly induced by hypoxia. In addition to the previously demonstrated LOX, we characterize LOXL2 as a direct transcriptional target of HIF-1. We demonstrate that activation of lysyl oxidases is required and sufficient for hypoxic repression of E-cadherin, which mediates cellular transformation and takes effect in cellular invasion assays. Our data support a molecular pathway from hypoxia to cellular transformation. It includes up-regulation of HIF and subsequent transcriptional induction of LOX and LOXL2, which repress E-cadherin and induce epithelial to mesenchymal transition. Lysyl oxidases could be an attractive molecular target for cancers of epithelial origin, in particular because they are partly extracellular.

PURPOSE: It has been reported that lysyl oxidase (LOX) is a hypoxia-responsive factor and is associated with the malignant progression of carcinoma. The aim of this study was to clarify the relationship between the epithelial-mesenchymal transition (EMT) and LOX in gastric cancer cells under hypoxia. METHODS: Two gastric cancer cell lines, OCUM-2MD3 and OCUM-12, were used in an in vitro study. The effect of LOX small interfering RNA (siRNA) on the EMT and motility of gastric cancer cells under hypoxic condition was analyzed by reverse transcription PCR, Western blot, a wound-healing assay, and an invasion assay. Correlations between LOX expression and the clinicopathological features of 544 patients with gastric carcinoma were examined immunohistochemically. RESULTS: Hypoxic conditions increased the number of polygonal or spindle-shaped cells resulting from EMT in gastric cancer cells. The EMT of cancer cells induced by hypoxia was inhibited by treatment with LOX siRNA. The number of migrating and invading gastric cancer cells in hypoxia was significantly decreased by LOX knockdown. LOX siRNA significantly increased the E-cadherin level and decreased the vimentin level of gastric cancer cells. LOX expression was significantly associated with invasion depth, tumor differentiation, lymph node metastasis, lymphatic invasion, venous invasion, and peritoneal metastasis. Multivariable analysis revealed that LOX was an independent parameter for overall survival. CONCLUSION: LOX affects the EMT of gastric cancer cells in hypoxic conditions. LOX expression is a useful prognostic factor for patients with gastric cancer.

BACKGROUND: Triple negative breast cancer (TNBC) accounts for approximately 15% of breast cancers. It is associated with a poor prognosis and typically earlier onset of metastasis in comparison with other breast cancer subtypes. Since TNBC lacks the expression of estrogen and progesterone receptors and Her2 status is also negative, there is currently no target that can be used for systemic therapy. epithelial-mesenchymal transition (EMT) plays an important role in tumor progression and metastasis. In this study, we examined a subset of EMT markers consisting of Snail, Twist-1 and Lox in TNBC and non-TNBC breast cancer subtypes and analyzed their expression pattern in regard to subtype, clinico-pathological parameters and prognosis. EXPERIMENTAL DESIGN: We analyzed 659 breast cancer samples from two tissue microarrays. Breast cancer samples were categorized into two groups according to hormone receptor expression and Her2 status (n=146 were triple negative, n=513 were non triple-negative). Immunohistochemical expression of Snail, Twist-1 and Lox was semi-quantitatively analyzed using a three-tiered (weak-moderate-strong) scoring system. Results were statistically analyzed and correlated to clinico-pathological parameters and overall survival. RESULTS: Strong overexpression of Lox was significantly higher in triple negative breast cancers when compared to non triple-negative breast cancers (p<0.001). No difference was seen between the groups regarding Snail and Twist expression (p>0.05). In addition, Lox expression was significantly stronger in poorly differentiated (G3) breast cancers (p<0.001 for Lox). CONCLUSIONS: The EMT marker Lox has a differential expression pattern in breast cancer, being significantly overexpressed in triple negative breast cancers. We could not link this expression to prognosis, however, this marker might be explored in future studies as possible target for systemic therapy of TNBC.CI - Copyright (c) 2018 Elsevier Inc. All rights reserved.

Lower grade gliomas (LGGs) have highly diverse clinical phenotypes. The histological grade and type are insufficient to accurately predict the clinical outcomes of patients with LGGs. Therefore, identification of biomarkers that can facilitate the prediction of clinical outcomes in LGGs is urgently needed. Gene expression of LOX has been identified as a biomarker for various cancers. However, the clinical significance of LOX expression in LGGs has not been investigated. In this study, we analyzed the glioma RNA-seq dataset from TCGA (The cancer Genome atlas) and identified lysyl oxidase (LOX) as a potential biomarker for LGGs. Kaplan-Meier survival analysis revealed that high LOX expression is associated with worse overall survival and recurrence free survival in LGG patients. Besides, high LOX expression is associated with poor response to primary therapy, follow-up treatment, targeted molecular therapy, and radiation therapy. Univariate and multivariate Cox regression analyses further confirmed LOX expression as an independent prognostic factor for LGG patients. Finally, we observed that LOX expression is significantly correlated with EMT (epithelial to mesenchymal transition) and IDH1 status in LGGs. In conclusion, our analyses suggest that LOX expression is a potential biomarker for prognosis and therapeutic response in LGGs.CI - Copyright (c) 2018. Published by Elsevier Inc.

Lysyl oxidase (LOX) is a copper-dependent amine oxidase that plays a critical role in pulmonary fibrosis. Our previous study demonstrated that epithelial-to-mesenchymal transition (EMT) was strongly associated with paraquat (PQ) induced pulmonary fibrosis. This present study was aimed to evaluate the potential involvement of LOX on EMT in the process of pulmonary fibrosis induced by PQ. We established an in vivo rat model and an in vitro cell model induced by PQ treatment and found that LOX protein expression was significantly up-regulated and collagen deposition was enhanced in rats. The EMT process was strongly found in A549 and RLE-6TN cells after PQ exposure. After inactivating LOX with an inhibitor, pulmonary fibrosis was significantly reduced and EMT was also suppressed. Additionally, small interfering RNA (siRNA) targeting LOX was used to silence LOX expression to observe EMT in A549 cells. As a result, LOX could promote the progress of EMT, and inactivating LOX alleviated the EMT process in PQ-induced pulmonary fibrosis and mesenchymal-to-epithelial transition (MET) occurred after inactivating LOX in vitro and in vivo. In conclusion, LOX could promote the progress of EMT and inactivating LOX alleviated EMT in PQ-induced pulmonary fibrosis. Therefore, LOX could potentially be a new candidate therapeutic target for pulmonary fibrosis induced by PQ by regulating the balance between EMT and MET.