Identification of lung adenocarcinoma subtypes and a prognostic signature based on activity changes of the hallmark and immunologic gene sets.

Background: Lung adenocarcinoma (LUAD) has a complex tumor heterogeneity. Our research attempts to clearness LUAD subtypes and build a reliable prognostic signature according to the activity changes of the hallmark and immunologic gene sets. Methods: According to The Cancer Genome Atlas (TCGA) - LUAD dataset, changes in marker and immune gene activity were analyzed, followed by identification of prognosis-related differential gene sets (DGSs) and their related LUAD subtypes. Survival analysis, correlation with clinical characteristics, and immune microenvironment assessment for subtypes were performed. Moreover, the differentially expressed genes (DEGs) between different subtypes were identified, followed by the construction of a prognostic risk score (RS) model and nomogram model. The tumor mutation burden (TMB) and tumor immune dysfunction and exclusion (TIDE) of different risk groups were compared. Results: Two LUAD subtypes were determined according to the activity changes of the hallmark and immunologic gene sets. Cluster 2 had worse prognosis, more advanced tumor and clinical stages than cluster 1. Moreover, a prognostic RS signature was established using two LUAD subtype-related DEGs, which could stratify patients at different risk levels. Nomogram model incorporated RS and clinical stage exerted good prognostic performance in LUAD patients. A shorter survival time and higher TMB were observed in the high-risk patients. Conclusions: Our findings revealed that our constructed prognostic signature could exactly predict the survival status of LUAD cases, which was helpful in predicting the prognosis and guiding personalized therapeutic strategies for LUAD.

Interplay between menin and Dnmt1 reversibly regulates pancreatic cancer cell growth downstream of the Hedgehog signaling pathway.

Menin, the product of the Men1 gene, which is frequently mutated in pancreatic neuroendocrine tumors, acts as a chromatin-remodeling factor to modulate the transcription of cell cycle regulators by interacting with histone modification factors. However, the function of menin and its underlying mechanisms in pancreatic ductal adenocarcinoma remain unknown. Here, we found that menin inhibited pancreatic cancer cell growth in vitro and in vivo and that its expression was gradually lost during pancreatic carcinogenesis. Menin overexpression significantly activated the expression of the cyclin-dependent kinase (CDK) inhibitors p18 and p27, accompanied with a decrease in DNA methylation levels of p18 and p27 promoters. Mechanistically, we found that interaction of menin with DNA methyltransferase 1 (Dnmt1) competitively pulled down Dnmt1 from p18 and p27 promoters, leading to the downregulation of DNA methylation levels. Moreover, menin expression was suppressed by Dnmt1 downstream of the Hedgehog signaling pathway, and menin overexpression strongly antagonized the promotion effect of hedgehog signaling on pancreatic cancer cell proliferation. Taken together, the interaction between menin and Dnmt1 reversibly regulates pancreatic cancer cell growth downstream of Hedgehog pathways with complex mutual modulation networks, suggesting that the Hedgehog/Dnmt1/menin axis is a potential molecular target for pancreatic cancer therapy.

Activated estrogen receptor-mitogen-activated protein kinases cross talk confer acquired resistance to lapatinib.

BACKGROUND: The efficacy of lapatinib is limited by the development of acquired resistance. The aim of this study was to investigate the role of estrogen receptor (ER) signaling compensatory activation in acquired resistance to lapatinib in breast cancer cells BT474 and the related mechanism. METHODS: Acquired resistant cell model resistant (r)BT474 was generated with an increasing concentration of lapatinib. Real-time polymerase chain reaction and Western blotting were used to determine the changes of human epidermal growth factor receptor (HER)2 and ER pathways in breast cancer cell BT474 after treatment with lapatinib and the distinction between BT474 and rBT474. Methyl thiazolyl tetrazolium and colony formation assays were employed to detect the proliferation of rBT474 and BT474 cells treated with lapatinib and/or an ER inhibitor, fulvestrant, respectively. RESULTS: Lapatinib could inhibit phosphorylation of HER2 and induce expression of forkhead-box protein O3a and progesterone receptor. Acquired resistant cell model rBT474 could grow in the presence of 5 µM lapatinib, with an apoptosis rate of only 5%. Significant inhibition of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT) pathway and the activation of the mitogen-activated protein kinases (MAPK) and ER pathways were detected in rBT474, compared with BT474. Furthermore, the expressions of Src phosphorylation and caveolin-1 were also upregulated. The viability of rBT474 was markedly suppressed by the lapatinib/fulvestrant combination in vitro, confirmed by the BT474 xenograft model. CONCLUSION: ER signaling compensatory activation may partly contribute to lapatinib acquired resistance in HER2-overexpressing/ERα-positive breast cancer cells, which might be related to PI3K/AKT inhibition and MAPK pathway activation.

Tumor suppressor Menin acts as a corepressor of LXRα to inhibit hepatic lipogenesis.

Menin, encoded by the MEN1 gene, was initially identified as a tumor suppressor for endocrine neoplasia. Our previous report showed that Menin enhances PPARα transactivity preventing triglyceride accumulation in the liver. Here, we further explore the role of Menin in liver steatosis. Transient transfection assays demonstrate that Menin inhibits the transcriptional activity of nuclear receptor liver X receptor α (LXRα). Accordingly, Menin overexpression results in reduced expression of LXRα target genes, such as lipogenic enzymes including SREBP-1c, FASN and SCD-1. Co-immunoprecipitation assays revealed physical interaction between Menin and LXRα. Collectively, our data suggest that Menin acts as a novel corepressor of LXRα and functions as a negative regulator of hepatic lipogenesis.

Recombinant attenuated Salmonella typhimurium carrying a plasmid co-expressing ENDO-VEGI151 and survivin siRNA inhibits the growth of breast cancer in vivo.

The aim of this study was to investigate the antitumor effect of a plasmid co-expressing ENDO-VEGI151 and survivin siRNA on breast cancer in nude mice, and to explore the feasibility of attenuated Salmonella typhimurium (S. typhimurium) as a delivery vector for cancer gene therapy in vivo. Three recombinant expression plasmids pENDO­VEGI151 (pEV), pSurvivin-siRNA (psi-survivin) and co-expressing plasmid pENDO-VEGI151/survivin­siRNA (pEV/si-survivin), were transferred into the attenuated S. typhimurium strain SL7207, respectively. MDA-MB-231 cells were infected with these recombinants in vitro, and the expression of ENDO-VEGI151 and survivin was detected. In order to detect S. typhimurium distribution and gene delivery efficiency in vivo, the plasmid pEGFP-N1 which encodes green fluorescent protein was transferred into SL7207, and the recombinant known as SL-pEGFP was orally administered to tumor-bearing nude mice. The gene transfer efficiency, distribution and survival time of the SL-pEGFP in vivo were evaluated by detection of GFP fluorescence. SL-pEGFP not only infected the cancer cells effectively, but also allowed the survival and expression of specific genes mainly in the xenografts of nude mice. To further identify the anticancer effects of these recombinants in vivo, mice burdened with xenografts were randomly divided into 6 groups, which were subjected to intragastric administration of vehicle, SL7207, SL-pcDNA3.1, SL-pEV, SL-psi-survivin and SL-pEV/si-survivin, respectively. Eight weeks after implantation, tumor size, weight, inhibition rate, intratumoral microvessel density (MVD), apoptotic index (AI), ENDO­VEGI151 and survivin expression were evaluated. Compared with the SL-pEV or SL-psi-survivin-treated groups, the growth of tumors was significantly reduced in the SL-pEV/si-survivin group with an inhibition rate of 90.28 vs. 69.12 and 65.61%, respectively. MVD and the expression of survivin were decreased significantly in the SL-pEV/si-survivin-treated group, while AI increased significantly in the SL-pEV/si-survivin-treated group. These results indicated that attenuated S. typhimurium carrying the dual function plasmid pEV/si-survivin cannot only be specifically enriched in the tumor tissue, but also showed a synergistic antitumor effect in vivo.

Dietary restriction suppresses tumor growth, reduces angiogenesis, and improves tumor microenvironment in human non-small-cell lung cancer xenografts.

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide; however, only limited therapeutic treatments are available. The aim of present study was to elucidate the therapeutic effect of dietary restriction in human NSCLC xenografts. Adult female nude mice were injected subcutaneously in the right dorsal flank with NSCLC cell line A549 cells. 5 days after tumor implantation, animals were randomly divided into ad libitum-fed group (AL, 95% of average diary intake) or dietary-restriction-fed group (DR, 70% average diary intake). 24 days after implantation, it was found that DR inhibited tumor growth marked by lower tumor volume and weight. DR suppressed tumor proliferation marked by reduced proliferating cell nuclear antigen (PCNA) expression and activated mitochondria-mediated apoptosis. DR decreased microvessel density marked by decreased CD31 immunostaining and promoted vessel maturation marked by increased alpha-smooth muscle actin (α-SMA) and reduced Factor VIII expression. DR reduced intratumoral interstitial fluid pressure and attenuated tumor hypoxia detected by EF5 immunostaining. In addition, DR suppressed NFκB signaling pathway and downregulated its downstream proteins expression including cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). DR suppressed phosphoinositide 3-kinase (PI3K)/AKT signaling pathway. In conclusion, dietary restriction suppresses tumor growth, reduces angiogenesis, and improves tumor microenvironment in human non-small-cell lung cancer xenografts. Dietary restriction could thus be envisaged as a nutritional countermeasure against non-small-cell lung cancer.

Menin prevents liver steatosis through co-activation of peroxisome proliferator-activated receptor alpha.

Fatty liver is strongly associated with metabolic syndrome. Here, we show that the impaired hepatic expression of menin, the product of the MEN1 (multiple endocrine neoplasia type 1) tumor suppressor gene, represents a common feature of several fatty liver mouse models. The liver specific ablation of MEN1 gene expression in healthy mice induced hepatic steatosis under high-fat dietary conditions. Moreover, overexpression of menin in livers of steatotic db/db mice reduced liver triglyceride accumulation. At the molecular level, we found that menin acts synergistically with the nuclear receptor PPARα to control gene expression of fatty acid oxidation. Collectively, these data suggest a crucial role for menin as an integrator of the complex transcriptional network controlling hepatic steatosis.

[Expression of Aurora-B in non-small cell lung cancer and its clinical significance].

OBJECTIVE: To study the expression of Aurora-B in non-small cell lung cancer (NSCLC) tissues and NSCLC cell lines. METHOD: Aurora-B expression was examined using immunohistochemical SP method in 91 stage I and 69 stage II-III NSCLC tissues and 40 adjacent tissues. The mRNA and protein expressions of Aurora-B in NSCLC cell lines (A549, H460 and H1299) were examined by RT-PCR and Western blotting, respectively. RESULTS: The protein expression of Aurora-B was detected in 77.7% (94/121) of the tumor tissues and 9.8% (4/41) of the adjacent tissues, showing a significant difference between them (P<0.01). The positivity rate of Aurora-B protein was not related with the gender and age of NSCLC patients, but with lymph node metastasis, differentiation and histological type of NSCLC (P<0.05). Aurora-B was expressed in all the NSCLC cell lines (A549, H460 and H1299) at both mRNA and protein levels. A549 cells showed the highest expression of Aurora-B. CONCLUSION: Aurora-B protein is highly expressed in NSCLC tissues and cell lines, and may play a crucial role in the invasion, metastasis and development of NSCLC. The mRNA and protein expression levels of Aurora-B differ significantly between different NSCLC cell lines.

Regulation of aromatase P450 expression by puerarin in endometrial cell line RL95-2.

OBJECTIVE: To study the effects of puerarin on the aromatase P450 (P450(arom)) mRNA expression and the effects of low-dose puerarin on transcription factors of the P450(arom) gene (P II) 5'-flanking region. METHODS: The effects of puerarin on the P450(arom) mRNA expression were determined by real-time polymerase chain reaction (RT-PCR). The 5'-flanking region was amplified by PCR using human genomic cDNA as a template. By means of the restriction sites and sequence confirmation, the PCR product was cloned into reporter vector. Series of sequential deletion reporter constructs were transiently transfected into RL95-2 cells which were treated with or without puerarin. Luciferase activity was measured by Dual-Luciferase Reporter Assay System and Luminoskan Ascent luminometer. Furthermore, by using web-based search program, the most possible cis-acting elements and transcription factors were evaluated. RESULTS: The data demonstrated that low-dose puerarin treatment could decrease P450(arom) expression at mRNA level compared to dimethyl sulphoxide (DMSO) treatment (P<0.01), and puerarin (10(-7)mol/L) had a time-course effect on P450(arom) mRNA expression, which reached the bottom at 12h (P<0.01). Cells transfected with the -763/+8 bp constructs showed decrease in relative luciferase activity after puerarin (10(-7)mol/L) treatment compared to DMSO treatment (P<0.05), indicating an essential regulatory site between -763 bp and -543 bp responsible for the transcription suppression by puerarin. Furthermore, the most possible transcription factors, which turned out to be AP-1(c-jun/c-fos) at -410/-401 bp were also evaluated. The activity of exogenous AP-1 was reduced after 12 hours of puerarin treatment (P<0.05). The inhibition of c-jun mRNA also showed a time-course effect, which bottomed out at 12h in parallel with that of P450(arom) (P<0.01). The protein level of c-jun was also down-regulated by puerarin (10(-7)mol/L) treatment at 12h. CONCLUSION: The suppression of P450(arom) expression and activity may be associated with the down-regulation of transcription factor AP-1/c-jun. This partially explains the mechanisms whereby puerarin treats endometriosis.

[Effects of fusion gene encoding the hVEGF165 and fused hirudin on restenosis of injured carotid artery induced by angioplasty].

OBJECTIVE: To study the effects of fusion gene encoding the hVEGF(165) and fused hirudin on restenosis of injured carotid artery. METHODS: A fusion gene encoding hVEGF(165) and fused hirudin (hVEGF(165)-FH) was constructed and clone into the eukaryotic expression vector pcDNA3.0, thus constructing the plasmid VEGF(165)-FH/pcDNA3.0. Its activities to stimulate endothelial cell proliferation and to inhibit thrombosis were identified. Sixteen New Zealand rabbits underwent ligation of external carotid artery and a balloon was inserted into the common carotid artery for 30 minutes so as to construct model of restenosis of injured carotid artery. Then the rabbits were randomly divided into 4 equal groups. In the one-week and 3-week control groups, 400 microg of DNA of the plasmid pcDNA3.0 were transfused into the arterial lumen at the injured part immediately after the angioplasty, and 400 microg of DNA of the plasmid VEGF(165)-FH/pcDNA3.0 were transfused in the 1-week and 3-week experimental groups. One week and 3 weeks after the treatment peripheral blood samples were collected to detect the activated partial thromboplastin time (APTT), thrombin time (TT), and platelet aggregation rate, and then the rabbits underwent angiography to observe the situation of restenosis. Then the rabbits were killed to take out the injured part of artery to undergo pathological examination and Western blotting. RESULTS: The values of APTT, TT, and platelet aggregation rate were not significantly different among the 4 groups. Angiography conducted 1 and 3 weeks later showed that restenosis was significantly mild in the 2 experimental groups in comparison with the 2 control groups, and severe restenosis was seen in the 3-week control group. Western blotting showed that expression of specific fused protein could be found in the 1-week and 3-week experimental group, the amount of the latter group being less than that of the former group; however, no expression of specific fused protein was found in the 2 control groups. Pathological examination showed that the narrowing of lumen 1-week and 3-week experimental groups were 11.50% and 19.75%, both significantly milder than those of the 1-week and 3-week control groups (33.25% and 52.25% respectively, both f P < 0.05). VB staining showed that the (intima/media (I/M) ratio of the 1-week and 3-week experimental groups were 0.12 and 0.35 respectively, both significantly lower than those of the 2 control groups (0.50 and 1.07 respectively, both P < 0.05). CONCLUSION: Accelerating re-endothelialization and inhibiting thrombosis, the fused gene hVEGF(165)-FH effectively prevents restenosis after angioplasty, On the basis of endothelial repair, construction of fused genes with double even multiple targets may be a novel and potential therapeutic approach for restenosis after percutaneous coronary intervention.

Expression, purification, and C-terminal amidation of recombinant human glucagon-like peptide-1.

Human glucagon-like peptide-1 (hGLP-1) (7-36) amide, a gastrointestinal hormone with a pharmaceutical potential in treating type 2 diabetes mellitus, is composed of 30 amino acid residues as a mature protein. We report here the development of a method for high-level expression and purification of recombinant hGLP-1 (7-36) amide (rhGLP-1) through glutathione S-transferase (GST) fusion expression system. The cDNA of hGLP-1-Leu, the 31st-residue leucine-extended precursor peptide, was prepared by annealing and ligating of artificially synthetic oligonucleotide fragments, inserted into pBluescript SK (+/-) plasmid, and then cloned into pGEX-4T-3 GST fusion vector. The fusion protein GST-hGLP-1-Leu, expressed in Escherichia coli strain BL21 (DE3), was purified by affinity chromatography after high-level culture and sonication of bacteria. Following cleavage of GST-hGLP-1-Leu by cyanogen bromide, the recombinant hGLP-1-Leu was released from fusion protein, and purified using QAE Sepharose ion exchange and RP C(18) chromatography. After purification, the precursor hGLP-1-Leu was transacylated by carboxypeptidase Y, Arg-NH(2) as a nucleophile, to produce rhGLP-1. Electrospray ionization mass spectrometry showed the molecular weight was as expected. The biological activity of rhGLP-1 in a rat model demonstrated that plasma glucose concentrations were significantly lower and insulin concentrations higher after intraperitoneal injection of rhGLP-1 together with glucose compared with glucose alone (P < 0.001).