A novel immune-related ceRNA network that predicts prognosis and immunotherapy response in lung adenocarcinoma.

BACKGROUND: The tumor microenvironment plays an important role in the progression and malignancy of lung adenocarcinoma and affects the immunotherapy response. There is increasing evidence that long non-coding RNAs (lncRNAs) as competing endogenous RNAs (ceRNAs) have significant functions in the development and treatment response of various kinds of cancer. This study aimed to explore the association between immune-related lncRNA-microRNA (miRNA)-messenger RNA (mRNA)-ceRNA networks, and the prognosis of and immunotherapy response in lung adenocarcinoma. METHODS: RNA-sequencing (RNA-seq) and miRNA-seq data from The Cancer Genome Atlas (TCGA) were used to evaluate the infiltration of immune cells in lung adenocarcinoma samples by undertaking a single-sample gene set enrichment analysis (ssGSEA) to divide the cells into high and low immune cell infiltration groups. The differentially expressed mRNA (DEmRNA) was further analyzed by a weighted gene co-expression network analysis (WGCNA), search tool for recurring instances of neighboring genes (STRING), and Cytoscape to select hub genes. The ceRNA network was constructed using Cytoscape. Additionally, survival analyses were conducted to screen out prognostic candidate genes. RESULTS: Seven thousand five hundred and thirty-eight mRNAs, 540 lncRNAs, and 138 miRNAs were found to be differentially expressed between the high and low immune cell infiltration groups. The two DEmRNA modules most significantly associated with immune cell infiltration were further analyzed, and four clusters, including 179 DEmRNAs, were selected based on Molecular Complex Detection (MCODE) scores. The selected DEmRNAs in the four clusters were mainly enriched in pathways involved in regulating the immune response. Ultimately, a ceRNA network of SNHG6-hsa-miR-30e-5p-CYSLTR1 was identified as being associated with the prognosis of and immunotherapy response in lung adenocarcinoma. CONCLUSIONS: The present study extends understandings of immune-related lncRNA-miRNA-mRNA-ceRNA networks and identifies novel targets and a regulatory pathway for anti-tumor immunotherapy.

Resistin increases cisplatin-induced cytotoxicity in lung adenocarcinoma A549 cells via a mitochondria-mediated pathway.

Lung cancer is the most commonly diagnosed cancer with a high mortality rate. Cisplatin is one of the most important chemotherapeutic agents for the treatment of lung cancer patients, especially in advanced stages. Recent studies show that cisplatin may interact with mitochondria to induce apoptosis, which may partly account for its cytotoxicity. In the study, we explored the effect of resistin on cisplatin-induced cytotoxicity in A549 cells and assessed whether mitochondria-dependent apoptosis was involved. Our results found that 25 ng/ml resistin could significantly increase cisplatin-induced apoptosis and G2/M phase arrest, enhance reactive oxygen species generation, exacerbate the collapse of mitochondrial membrane potential, promote the distribution of cytochrome C in the cytoplasm from mitochondria, and activate caspase 3. Therefore, the results suggested that resistin might increase cisplatin-induced cytotoxicity via a mitochondria-mediated pathway in A549 cells. However, the precise mechanism remains to be explored in the future.

Inhibitory Effects of (-)-Epigallocatechin-3-gallate on Esophageal Cancer.

There is epidemiological evidence showing that drinking green tea can lower the risk of esophageal cancer (EC). The effect is mainly attributed to tea polyphenols and their most abundant component, (-)-epigallocatechin-3-gallate (EGCG). The possible mechanisms of tumorigenesis inhibition of EGCG include its suppressive effects on cancer cell proliferation, angiogenesis, DNA methylation, metastasis and oxidant stress. EGCG modulates multiple signal transduction and metabolic signaling pathways involving in EC. A synergistic effect was also observed when EGCG was used in combination with other treatment methods.

Antidiabetic Effects of Tea.

Diabetes mellitus (DM) is a chronic endocrine disease resulted from insulin secretory defect or insulin resistance and it is a leading cause of death around the world. The care of DM patients consumes a huge budget due to the high frequency of consultations and long hospitalizations, making DM a serious threat to both human health and global economies. Tea contains abundant polyphenols and caffeine which showed antidiabetic activity, so the development of antidiabetic medications from tea and its extracts is increasingly receiving attention. However, the results claiming an association between tea consumption and reduced DM risk are inconsistent. The advances in the epidemiologic evidence and the underlying antidiabetic mechanisms of tea are reviewed in this paper. The inconsistent results and the possible causes behind them are also discussed.

Tea Polysaccharides and Their Bioactivities.

Tea (Camellia sinensis) is a beverage beneficial to health and is also a source for extracting bioactive components such as theanine, tea polyphenols (TPP) and tea polysaccharides (TPS). TPS is a group of heteropolysaccharides bound with proteins. There is evidence showing that TPS not only improves immunity but also has various bioactivities, such as antioxidant, antitumor, antihyperglycemia, and anti-inflammation. However, inconsistent results concerning chemical composition and bioactivity of TPS have been published in recent years. The advances in chemical composition and bioactivities of TPS are reviewed in the present paper. The inconsistent and controversial results regarding composition and bioactivities of TPS are also discussed.

Suppressive Effects of Tea Catechins on Breast Cancer.

Tea leaf (Camellia sinensis) is rich in catechins, which endow tea with various health benefits. There are more than ten catechin compounds in tea, among which epigallocatechingallate (EGCG) is the most abundant. Epidemiological studies on the association between tea consumption and the risk of breast cancer were summarized, and the inhibitory effects of tea catechins on breast cancer, with EGCG as a representative compound, were reviewed in the present paper. The controversial results regarding the role of tea in breast cancer and areas for further study were discussed.