Lentivirus-mediated silencing of HOTAIR lncRNA restores gefitinib sensitivity by activating Bax/Caspase-3 and suppressing TGF-α/EGFR signaling in lung adenocarcinoma.

Secondary resistance is a major limitation in the efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor treatment of lung cancer. Previous studies have shown that expression of the long non-coding RNA HOX transcript antisense RNA (HOTAIR) is upregulated in lung cancer, which is correlated with metastasis and poor prognosis. However, the precise role of HOTAIR and its effects on gefitinib resistance in human lung adenocarcinoma are not known. To address this issue, in the present study we established a gefitinib-resistant (R)PC-9 human lung adenocarcinoma cell line and examined cell viability with the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. We found that gefitinib concentrations <10 µM inhibited the viability of PC-9 but not RPC-9 cells in a dose-dependent manner. Lentivirus-mediated HOTAIR RNA interference induced cell apoptosis and S-phase arrest, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and flow cytometry. Consistent with these observations, HOTAIR suppression was associated with tumor shrinkage and restoration of gefitinib sensitivity in RPC-9 xenograft mice. Immunohistochemical analyses and western blot revealed that HOTAIR silencing resulted in the upregulation of B cell lymphoma 2-associated X protein (Bax), Caspase-3 and transforming growth factor α (TGF-α) and downregulation of EGFR and B cell lymphoma 2 (Bcl-2) levels. These results indicate that HOTAIR normally prevents the activation of Bax/Caspase-3 while inducing TGF-α/EGFR signaling. Thus, targeting HOTAIR may be a novel therapeutic strategy for treating gefitinib-resistant lung adenocarcinoma.

Overexpression of forkhead box M1 and urokinase-type plasminogen activator in gastric cancer is associated with cancer progression and poor prognosis.

Forkhead box M1 (FOXM1) and urokinase-type plasminogen activator (uPA) are overexpressed and associated with the pathogenesis of multiple types of human malignancy. The aims of the present study were to investigate FOXM1 and uPA expression levels in human gastric cancer using tissue microarray techniques; determining their association with clinicopathological characteristics as well as their prognostic value. Tissue microarray blocks, comprising 436 gastric cancer cases and 92 non-cancerous adjacent normal gastric tissues, were analyzed for FOXM1 and uPA protein expression levels using immunohistochemistry. The results were analyzed statistically in association with various clinicopathological characteristics and overall survival rates. FOXM1 and uPA were detected in 78.67 (343/436) and 83.26% (363/436) of cancer samples, respectively. FOXM1 and uPA were not expressed in the 92 normal gastric tissue samples. In gastric cancer, FOXM1 and uPA levels were associated with tumor size, depth of invasion, tumor-node-metastasis (TNM) stage, lymph node metastasis, vessel invasion and distant metastases. The overall survival rate was significantly decreased in patients expressing FOXM1 and uPA compared with FOXM1- and uPA-negative patients. Coxs multivariate analysis revealed that age, depth of invasion and expression levels of FOXM1 and uPA are independent predictors of survival in patients with gastric cancer. These results indicated that increased FOXM1 and uPA expression levels are associated with the invasive and metastatic processes in human gastric cancer, and inversely associated with patient prognosis. Therefore, FOXM1 and uPA may serve as novel prognostic markers independent of, but supplementing, the TNM staging system.

Sirtuin 1 Activator SRT1720 Protects Against Lung Injury via Reduction of Type II Alveolar Epithelial Cells Apoptosis in Emphysema.

In chronic obstructive pulmonary disease (COPD), two major pathological changes that occur are the loss of alveolar structure and airspace enlargement. Type II alveolar epithelial cells (AECII) play a vital role in maintaining alveolar homeostasis and lung tissue repair. Sirtuin 1 (SIRT1), a NAD(+)-dependent histone deacetylase, regulates many pathophysiological processes including inflammation, apoptosis, cellular senescence and stress resistance. The main aim of this study was to investigate whether SRT1720, a pharmacological SIRT1 activator, could protect against AECII apoptosis in rats with emphysema caused by cigarette smoke exposure and intratracheal lipopolysaccharide instillation in vivo. During the induction of emphysema in rats, administration of SRT1720 improved lung function including airway resistance and pulmonary dynamic compliance. SRT1720 treatment up-regulated the levels of surfactant protein (SP)A, SPC, SIRT1 and forkhead box O 3, increased SIRT1 activity, down-regulated the level of p53 and inhibited AECII apoptosis. Lung injury caused by emphysema was alleviated after SRT1720 treatment. SRT1720 could protect against AECII apoptosis in rats with emphysema and thus could be used in COPD treatment.

Therapeutic effects of amniotic fluid-derived mesenchymal stromal cells on lung injury in rats with emphysema.

BACKGROUND: In chronic obstructive pulmonary disease (COPD), two major pathological changes that occur are the loss of alveolar structure and airspace enlargement. To treat COPD, it is crucial to repair damaged lung tissue and regenerate the lost alveoli. Type II alveolar epithelial cells (AECII) play a vital role in maintaining lung tissue repair, and amniotic fluid-derived mesenchymal stromal cells (AFMSCs) possess the characteristics of regular mesenchymal stromal cells. However, it remains untested whether transplantation of rat AFMSCs (rAFMSCs) might alleviate lung injury caused by emphysema by increasing the expression of surfactant protein (SP)A and SPC and inhibiting AECII apoptosis. METHODS: We analyzed the phenotypic characteristics, differentiation potential, and karyotype of rAFMSCs, which were isolated from pregnant Sprague-Dawley rats. Moreover, we examined the lung morphology and the expression levels of SPA and SPC in rats with emphysema after cigarette-smoke exposure and intratracheal lipopolysaccharide instillation and rAFMSC transplantation. The ability of rAFMSCs to differentiate was measured, and the apoptosis of AECII was evaluated. RESULTS: In rAFMSCs, the surface antigens CD29, CD44, CD73, CD90, CD105, and CD166 were expressed, but CD14, CD19, CD34, and CD45 were not detected; rAFMSCs also strongly expressed the mRNA of octamer-binding transcription factor 4, and the cells could be induced to differentiate into adipocytes and osteocytes. Furthermore, rAFMSC treatment up-regulated the levels of SPA, SPC, and thyroid transcription factor 1 and inhibited AECII apoptosis, and rAFMSCs appeared to be capable of differentiating into AECII-like cells. Lung injury caused by emphysema was alleviated after rAFMSC treatment. CONCLUSIONS: rAFMSCs might differentiate into AECII-like cells or induce local regeneration of the lung alveolar epithelium in vivo after transplantation and thus could be used in COPD treatment and lung regenerative therapy.

[In vitro differentiation of rat amniotic fluid-derived mesenchymal stem cells into type II alveolar epithelial cells].

OBJECTIVE: To explore the in vitro differentiation of rat amniotic fluid-derived mesenchymal stem cells (AF-MSCs) into type II alveolar epithelial cells (AECII). METHODS: Flow cytometry was used to analyze the phenotypes of AF-MSCs from 10 pregnant Sprague-Dawley rats. And the Oct-4 mRNA expression level was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Rat embryonic stem cell was used as a positive control. According to different culturing methods, AF-MSCs were randomly divided into 5 groups of A (control group), B, C, D and E. After in vitro differentiation, SPA, SPB, SPC, SPD and TTF1 mRNA expressions were detected by qRT-PCR, SPA and SPC protein expressions measured by immunofluorescence and lamellar bodies observed by transmission electron microscopy. RESULTS: AF-MSCs could grow spirally in L-DMEM medium containing 20% fetal bovine serum and 4 µg/L basic fibroblast growth factor. The expressions of such surface antigens of AF-MSCs (third passage) as CD29 (99.1 ± 7.9)%, CD44 (99.2 ± 7.4)%, CD73 (75.6 ± 5.2)%, CD90 (98.9 ± 8.1)%, CD105 (92.9 ± 7.3)% and CD166 (89.3 ± 6.7)% were positive while CD34 and CD45 were negative. And the expression of Oct-4 mRNA (relative quantity: 0.690 ± 0.059) was significantly lower than rat embryonic stem cells (relative quantity: 1.000 ± 0.002) positive control group (P < 0.01). After in vitro differentiation, the expressions of SPA, SPB, SPC, SPD and TTF1 mRNA and SPA and SPC protein were negative in group A and positive in group B. The expressions of SPA, SPB, SPC, SPD and TTF1 mRNA (relative quantity: 0.426 ± 0.043, 0.368 ± 0.028, 0.492 ± 0.058, 0.327 ± 0.024 and 0.183 ± 0.018) and SPA and SPC protein in group B were significantly higher than other groups (all P < 0.01). Lamellar bodies could be found in the differentiated cells of group B. CONCLUSION: Rat AF-MSCs from amniotic fluid may differentiated into AECII like cells in vitro.

Differentiation of human amniotic fluid-derived mesenchymal stem cells into type II alveolar epithelial cells in vitro.

Type II alveolar epithelial cells (AECII) play a key role in maintaining normal alveolar homeostasis and repair. AECII derived from exogenous stem cells may provide novel treatment options for distal lung diseases. In this study, to explore whether amniotic fluid-derived mesenchymal stem cells (AFMSCs) may be induced to differentiate into AECII in vitro, AFMSCs were isolated from 15 independent samples of amniotic fluid, in which CD29, CD44, CD73, CD90, CD105 and CD166 were significantly expressed, but the expression of CD14, CD19, CD34 and CD45 was negative. Octamer-binding transcription factor 4 (OCT4) at both the mRNA and protein level was also significantly expressed in the AFMSCs. We demonstrate that AFMSCs cannot be induced to differentiate into AECII using KnockOut™ serum replacement (KOSR) only. Surfactant protein (SP)A and SPC mRNA expression in the differentiated AFMSCs was significantly induced by the appropriate combination of KOSR, activin A and small airway basal medium (SABM). However, SPA and SPC expression was negative with an inappropriate induction. Lamellar bodies were observed only in the cells which were appropriately induced by KOSR, activin A and SABM. Thus, these results indicate that AFMSCs may be induced to differentiate into AECII-like cells in vitro with the use of the appropriate induction medium, including KOSR, activin A and SABM, suggesting that that AFMSCs have the potential for use in lung regenerative therapy.

ADAM17 mediates MMP9 expression in lung epithelial cells.

The purposes were to study the role of lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α/nuclear factor-κB (NF-κB) signaling in matrix metalloproteinase 9 (MMP9) expression in A549 cells and to investigate the effects of lentivirus-mediated RNAi targeting of the disintegrin and metalloproteinase 17 (ADAM17) gene on LPS-induced MMP9 expression. MMP9 expression induced by LPS in A549 cells was significantly increased in a dose- and time-dependent manner (p<0.05). Pyrrolidine dithiocarbamate (PDTC) and a TNFR1 blocking peptide (TNFR1BP) significantly inhibited LPS-induced MMP9 expression in A549 cells (p<0.05). TNFR1BP significantly inhibited LPS-induced TNF-α production (p<0.05). Both PDTC and TNFR1BP significantly inhibited the phosphorylation of IκBα and expression of phosphorylation p65 protein in response to LPS (p<0.05), and the level of IκBα in the cytoplasm was significantly increased (p<0.05). Lentivirus mediated RNA interference (RNAi) significantly inhibited ADAM17 expression in A549 cells. Lentivirus-mediated RNAi targeting of ADAM17 significantly inhibited TNF-α production in the supernatants (p<0.05), whereas the level of TNF-α in the cells was increased (p<0.05). Lentiviral ADAM17 RNAi inhibited MMP9 expression, IκBα phosphorylation and the expression of phosphorylation p65 protein in response to LPS (p<0.05). PDTC significantly inhibited the expression of MMP9 and the phosphorylation of IκBα, as well as the expression of phosphorylation p65 protein in response to TNF-α (p<0.05). Lentiviral RNAi targeting of ADAM17 down-regulates LPS-induced MMP9 expression in lung epithelial cells via inhibition of TNF-α/NF-κB signaling.

Lentivirus-mediated ADAM17 RNA interference inhibited interleukin-8 expression via EGFR signaling in lung epithelial cells.

Interleukin (IL)-8 and neutrophil inflammation play a vital role in the pathogenesis of chronic inflammatory airway diseases. A disintegrin and metalloproteinase 17 (ADAM17) cleaves ectodomains of various transmembrane proteins and is an important regulator of almost every cellular event. The aim of this work was to investigate the roles of epidermal growth factor receptor (EGFR) signaling and ADAM17 in IL-8 expression induced by lipopolysaccharide (LPS) in A549 lung epithelial cells. In the present study, we found that transforming growth factor-α (TGF-α)-neutralizing Ab, EGFR-neutralizing Ab, and AG1478 significantly inhibited the phosphorylation of EGFR and IL-8 production induced by LPS. Lentivirus-mediated ADAM-17 RNA interference markedly inhibited ADAM-17 expression, the release of TGF-α, and the phosphorylation of EGFR and IL-8 expression. The results demonstrated that lentivirus-mediated RNA interference targeting ADAM17 suppressed IL-8 expression induced by LPS via inhibiting EGFR signaling, and ADAM17-EGFR signaling cascade mediated IL-8 production induced by LPS in lung epithelial cells.

[Apoptosis of human lung carcinoma cell line EBC-1 induced by N, N'-di-(m-methylphenyl)-3,6-dimethyl-1,4-dihydro-1,2,4,5-tetrazine-1,4-dicarboamide and its molecular mechanism].

OBJECTIVE: To study whether N, N'-di-(m-methylphenyi)-3,6-dimethyl-1,4-dihydro-1,2,4,5-tetrazine-1,4-dicarboamide (ZGDHu-1) inhibits proliferation and induces apoptosis in human lung carcinoma cell line EBC-1 cells and its molecular mechanism. METHODS: Different concentrations of ZGDHu-1 and different times of culture were used to treat EBC-1 cells in vitro. The inhibition of proliferation was measured by BrdU-ELISA. Cell apoptosis was detected by Annexin V/PI staining and cellular DNA fragmentation ELISA. Phosphorylated p38MAPK and STAT3 were examined by flow cytometry. The protein expressions of bcl-2, bax, p53, Fas, and caspase-3 were detected by Western blot analysis. RESULTS: ZGDHu-1 inhibited EBC-1 cell proliferation within a certain range of treating times and does, with a 24 h IC(50) of (295 ± 25) ng/ml, 48 h of (112 ± 8) ng/ml and 72 h of (23 ± 2) ng/ml. The EBC-1 cell apoptosis was confirmed by Annexin V/PI labeling and cellular DNA fragmentation ELISA in a dose-related manner. When EBC-1 cells were treated with 50, 200, and 500 ng/ml ZGDHu-1 for 48 h, the expression rates of phosphor-p38MAPK protein were 67.4%, 88.2%, 91.1%, respectively, and that of the control was 10.6%. That of STAT3 protein were 56.5%, 43.6% and 34.6%, respectively, and that of the control was 89.1%. The expression of bax, p53 and Fas protein was significantly increased, that of bcl-2 was not changed, and that of caspase-3 was significantly decreased by the ZGDHu-1 treatment. CONCLUSION: ZGDHu-1 can inhibit proliferation and induce apoptosis in EBC-1 cells. The mitochondrial pathway mediated by Fas may be one of its mechanisms. The apoptosis of EBC-1 cells may associate with up-regulation of phosphor-p38MAPK and down-regulation of phosphor-STAT3 in the cells.