Lung cancer cells induce senescence and apoptosis of pleural mesothelial cells via transforming growth factor-beta1

TGF-β as Predictive Marker and Pharmacological Target in Lung Cancer Approach

Lung cancer (LC) represents the leading cause of cancer incidence and mortality worldwide. LC onset is strongly related to genetic mutations and environmental interactions, such as tobacco smoking, or pathological conditions, such as chronic inflammation. Despite advancement in knowledge of the molecular mechanisms involved in LC, this tumor is still characterized by an unfavorable prognosis, and the current therapeutic options are unsatisfactory. TGF-β is a cytokine that regulates different biological processes, particularly at the pulmonary level, and its alteration has been demonstrated to be associated with LC progression. Moreover, TGF-β is involved in promoting invasiveness and metastasis, via epithelial to mesenchymal transition (EMT) induction, where TGF-β is the major driver. Thus, a TGF-β-EMT signature may be considered a potential predictive marker in LC prognosis, and TGF-β-EMT inhibition has been demonstrated to prevent metastasis in various animal models. Concerning a LC therapeutic approach, some TGF-β and TGF-β-EMT inhibitors could be used in combination with chemo- and immunotherapy without major side effects, thereby improving cancer therapy. Overall, targeting TGF-β may be a valid possibility to fight LC, both in improving LC prognosis and cancer therapy, via a novel approach that could open up new effective strategies against this aggressive cancer.

Blocking TGF-β type 1 receptor partially reversed skin tissue damage in experimentally induced atopic dermatitis in mice

Animals with impaired transforming growth factor (TGF)-β1 signaling developed spontaneous lethal autoimmune inflammationand autoimmune diseases. Moreover, evidence for modified TGF-β signaling in atopic dermatitis (AD) exists. Therefore, the goal of this study was to determine whether SB-431542, a potent and selective inhibitor of the TGF-β type 1 receptor (TGF-βR1), could attenuate such a severe reaction in mice. In addition, the molecular underpinnings the possible protective effects were also investigated. Repeated epicutaneous application of DNCB was performed on the ear and shaved dorsal skin of miceto induce AD-like symptoms and skin lesions. SB-431542 (1 mg/kg) was given by intra-peritoneal injection three times weekly for 3 weeks to assess the anti-pruritic effects. Serum levels of TGF-β1, TGF-βR1, latency-associated peptide (LAP), tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were assessed by ELISA. Moreover, the gene expression of TNF-α, IL-1β and IL-6 were determined. Apoptotic pathway was evaluated by measuring the activity of caspase-3 and by staining skin sections with anti-caspase-3 antibodies. We found that SB-431542 alleviated DNCB-induced AD-like symptoms as quantified by skin lesion,dermatitisscore, ear thickness and scratching behavior. In parallel, SB-431542 blocked DNCB-induced elevation in serum levels of TNF-α, TGF-β1, TGF-βR1, LAP, IL-1β, IL-6 and IgE. The collective results indicate that SB-431542 partially suppresses DNCB-induced AD in micevia reduction of TGF-β1 signaling pathway associated with inhibition of inflammation and apoptosis.

Dexamethasone induced apoptosis of A549 cells via the TGF-β1/Smad2 pathway

Lung cancers are the most commonly diagnosed malignant tumors, and are one of the leading causes of morbidity and mortality worldwide. Dexamethasone (DEX) serves an important function in the regulation of lung cancer cell proliferation; however, the mechanisms involved still remain unknown. In the present study, the effects of DEX on A549 cell proliferation and apoptosis were examined, in addition to the potential downstream regulatory mechanisms underlying these effects. A549 cells were treated with different concentrations of DEX at 12, 24 and 48 h time points, followed by the addition of SB431542, an inhibitor of the TGF-β1 receptor, to block the TGF-β1 signaling pathway. Cell proliferation was analyzed using a 3-(4,5-diethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt. The apoptosis rate was measured by Hoechst 33342 and Annexin V/propidium iodide staining and the expression of transforming growth factor (TGF)-β1, Smad family member 2 (Smad2) and caspase-3 were assessed by western blot. The results from the present study demonstrated that the proliferation of A549 cells decreased and the apoptosis rate significantly increased following DEX treatment (P<0.05). Furthermore, the expression of TGF-β1, Smad2 and caspase-3 were significantly increased following DEX stimulation (P<0.05), the effects of which were abrogated by the addition of the TGF-β1 receptor inhibitor, SB431542 (P<0.05). DEX-induced apoptosis in A549 cells, and this effect was abrogated by SB431542, an inhibitor of TGF-β1 receptor signaling, which indicated that the TGF-β1/Smad2 pathway may be associated with this process and SB431542 may function as an antitumor drug in the future.

Comprehensive analysis of the long noncoding RNA HOXA11-AS gene interaction regulatory network in NSCLC cells

Background

Long noncoding RNAs (lncRNAs) are related to different biological processes in non-small cell lung cancer (NSCLC). However, the possible molecular mechanisms underlying the effects of the long noncoding RNA HOXA11-AS (HOXA11 antisense RNA) in NSCLC are unknown.

Methods

HOXA11-AS was knocked down in the NSCLC A549 cell line and a high throughput microarray assay was applied to detect changes in the gene profiles of the A549 cells. Bioinformatics analyses (gene ontology (GO), pathway, Kyoto Encyclopedia of Genes and Genomes (KEGG), and network analyses) were performed to investigate the potential pathways and networks of the differentially expressed genes. The molecular signatures database (MSigDB) was used to display the expression profiles of these differentially expressed genes. Furthermore, the relationships between the HOXA11-AS, de-regulated genes and clinical NSCLC parameters were verified by using NSCLC patient information from The Cancer Genome Atlas (TCGA) database. In addition, the relationship between HOXA11-AS expression and clinical diagnostic value was analyzed by receiver operating characteristic (ROC) curve.

Results

Among the differentially expressed genes, 277 and 80 genes were upregulated and downregulated in NSCLC, respectively (fold change ≥2.0, P < 0.05 and false discovery rate (FDR) < 0.05). According to the degree of the fold change, six upregulated and three downregulated genes were selected for further investigation. Only four genes (RSPO3, ADAMTS8, DMBT1, and DOCK8) were reported to be related with the development or progression of NSCLC based on a PubMed search. Among all possible pathways, three pathways (the PI3K-Akt, TGF-beta and Hippo signaling pathways) were the most likely to be involved in NSCLC development and progression. Furthermore, we found that HOXA11-AS was highly expressed in both lung adenocarcinoma and squamous cell carcinoma based on TCGA database. The ROC curve showed that the area under curve (AUC) of HOXA11-AS was 0.727 (95% CI 0.663–0.790) for lung adenocarcinoma and 0.933 (95% CI 0.906–0.960) for squamous cell carcinoma patients. Additionally, the original data from TCGA verified that ADAMTS8, DMBT1 and DOCK8 were downregulated in both lung adenocarcinoma and squamous cell carcinoma, whereas RSPO3 expression was upregulated in lung adenocarcinoma and downregulated in lung squamous cell carcinoma. For the other five genes (STMN2, SPINK6, TUSC3, LOC100128054, and C8orf22), we found that STMN2, TUSC3 and C8orf22 were upregulated in squamous cell carcinoma and that STMN2 and USC3 were upregulated in lung adenocarcinoma. Furthermore, we compared the correlation between HOXA11-AS and de-regulated genes in NSCLC based on TCGA. The results showed that the HOXA11-AS expression was negatively correlated with DOCK8 in squamous cell carcinoma (r = −0.124, P = 0.048) and lung adenocarcinoma (r = −0.176, P = 0.005). In addition, RSPO3, ADAMTS8 and DOCK8 were related to overall survival and disease-free survival (all P < 0.05) of lung adenocarcinoma patients in TCGA.

Conclusions

Our results showed that the gene profiles were significantly changed after HOXA11-AS knock-down in NSCLC cells. We speculated that HOXA11-AS may play an important role in NSCLC development and progression by regulating the expression of various pathways and genes, especially DOCK8 and TGF-beta pathway. However, the exact mechanism should be verified by functional experiments.