Tumor suppressors and cell-cycle proteins in lung cancer

Cymbopogon proximus phytochemicals induce S-phase arrest in A549 lung cancer cell lines via CDK2/cyclin A2 inhibition: gas chromatography-mass spectrometry and molecular docking analyses

Cymbopogon proximus comprises several phytoconstituent classes that are reported to possess anticancer activity; however, studies on the anticancer potentials of the plant are lacking. C. proximus was extracted using solvents with increasing polarity. In-vitro cytotoxic activity of C. proximus extracts was examined against liver (HepG2), lung (A549), prostate (PC3), and bone (MG63) cell lines using MTT assay in comparison to doxorubicin. Flow cytometry was used to analyze the cell cycle for identification of the phase of inhibition. Chemical composition of the most active fraction was examined using the GC/MS technique. Molecular docking was used to explore the mechanism of cytotoxicity against A549, and the results were confirmed by Western blot analysis. Petroleum ether fraction was the highly effective fraction against A549 with IC50 = 14.02 ± 2.79. GC/MS analysis of Pet.Eth led to the identification of nine compounds in unsaponifiable matter and 27 components in the saponifiable fraction. Di-N-octyl phthalate, 3-β-hydroxylean-11.13(18)-dien-30-oic acid methyl ester, elemol hydrocarbons, linoelaidic acid and linoleic acid demonstrated the lowest docking binding scores and similar binding modes against CDK2 as compared to that attained by the native ligand R-Roscovitine "CDK2 ATP inhibitor". Western blot analysis demonstrated that CDK2/cyclinA2 protein expression has been suppressed in A549 cell lines by Pet.Eth fraction.

Cross-attention enables deep learning on limited omics-imaging-clinical data of 130 lung cancer patients

Deep-learning tools that extract prognostic factors derived from multi-omics data have recently contributed to individualized predictions of survival outcomes. However, the limited size of integrated omics-imaging-clinical datasets poses challenges. Here, we propose two biologically interpretable and robust deep-learning architectures for survival prediction of non-small cell lung cancer (NSCLC) patients, learning simultaneously from computed tomography (CT) scan images, gene expression data, and clinical information. The proposed models integrate patient-specific clinical, transcriptomic, and imaging data and incorporate Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome pathway information, adding biological knowledge within the learning process to extract prognostic gene biomarkers and molecular pathways. While both models accurately stratify patients in high- and low-risk groups when trained on a dataset of only 130 patients, introducing a cross-attention mechanism in a sparse autoencoder significantly improves the performance, highlighting tumor regions and NSCLC-related genes as potential biomarkers and thus offering a significant methodological advancement when learning from small imaging-omics-clinical samples.

ATF3 in atherosclerosis: a controversial transcription factor

Atherosclerosis, the pathophysiological basis of most malignant cardiovascular diseases, remains a global concern. Transcription factors play a key role in regulating cell function and disease progression in developmental signaling pathways involved in atherosclerosis. Activated transcription factor (ATF) 3 is an adaptive response gene in the ATF/cAMP response element binding (CREB) protein family that acts as a transcription suppressor or activator by forming homodimers or heterodimers with other ATF/CREB members. Appropriate ATF3 expression is vital for normal physiological cell function. Notably, ATF3 exhibits distinct roles in vascular endothelial cells, macrophages, and the liver, which will also be described in detail. This review provides a new perspective for atherosclerosis therapy by summarizing the mechanism of ATF3 in atherosclerosis, as well as the structure and pathophysiological properties of ATF3. KEY MESSAGES: • In endothelial cells, ATF3 overexpression aggravates oxidative stress and inflammation. • In macrophages and liver cells, ATF3 can act as a negative regulator of inflammation and promote cholesterol metabolism. • ATF3 can be used as a potential therapeutic factor in the treatment of atherosclerosis.

Loss of TIPE3 reduced the proliferation, survival and migration of lung cancer cells through inactivation of Akt/mTOR, NF-κB, STAT-3 signaling cascade

Lung cancer is the foremost cause of cancer related mortality among men and one of the most fatal cancers among women. Notably, the 5-year survival rate of lung cancer is very less; 5% in developing countries. This low survival rate can be attributed to factors like late stage diagnosis, rapid postoperative recurrences in the patients undergoing treatment and development of chemoresistance against different agents used for treating lung cancer. Therefore, in this study we evaluated the potential of a recently identified protein namely TIPE3 which is known as a transfer protein of lipid second messengers as a lung cancer biomarker. TIPE3 was found to be significantly upregulated in lung cancer tissues indicating its role in the positive regulation of lung cancer. Supporting this finding, knockout of TIPE3 was also found to reduce the proliferation, survival and migration of lung cancer cells and arrested the G2 phase of cell cycle through inactivation of Akt/mTOR, NF-κB, STAT-3 signaling. It is well evinced that tobacco is the major risk factor of lung cancer which affects both males and females. Therefore, this study also evaluated the involvement of TIPE3 in tobacco mediated lung carcinogenesis. Notably, this study shows for the first time that TIPE3 positively regulates tobacco induced proliferation, survival and migration of lung cancer through modulation of Akt/mTOR signaling. Thus, TIPE3 plays critical role in the pathogenesis of lung cancer and hence it can be specifically targeted to develop novel therapeutic strategies.

Reversible disruption of XPO1-mediated nuclear export inhibits respiratory syncytial virus (RSV) replication

Respiratory syncytial virus (RSV) is the primary cause of serious lower respiratory tract disease in infants, young children, the elderly and immunocompromised individuals. Therapy for RSV infections is limited to high risk infants and there are no safe and efficacious vaccines. Matrix (M) protein is a major RSV structural protein with a key role in virus assembly. Interestingly, M is localised to the nucleus early in infection and its export into the cytoplasm by the nuclear exporter, exportin-1 (XPO1) is essential for RSV assembly. We have shown previously that chemical inhibition of XPO1 function results in reduced RSV replication. In this study, we have investigated the anti-RSV efficacy of Selective Inhibitor of Nuclear Export (SINE) compounds, KPT-335 and KPT-185. Our data shows that therapeutic administration of the SINE compounds results in reduced RSV titre in human respiratory epithelial cell culture. Within 24 h of treatment, RSV replication and XPO1 expression was reduced, M protein was partially retained in the nucleus, and cell cycle progression was delayed. Notably, the effect of SINE compounds was reversible within 24 h after their removal. Our data show that reversible inhibition of XPO1 can disrupt RSV replication by affecting downstream pathways regulated by the nuclear exporter.

Targeting hyperactive TGFBR2 for treating MYOCD deficient lung cancer

Purpose: Clinical success of cancer therapy is severely limited by drug resistance, attributed in large part to the loss of function of tumor suppressor genes (TSGs). Developing effective strategies to treat those tumors is challenging, but urgently needed in clinic.

Experimental Design: MYOCD is a clinically relevant TSG in lung cancer patients. Our in vitro and in vivo data confirm its tumor suppressive function. Further analysis reveals that MYOCD potently inhibits stemness of lung cancer stem cells. Mechanistically, MYOCD localizes to TGFBR2 promoter region and thereby recruits PRMT5/MEP50 complex to epigenetically silence its transcription.

Conclusions: NSCLC cells deficient of MYOCD are particularly sensitive to TGFBR kinase inhibitor (TGFBRi). TGFBRi and stemness inhibitor synergize with existing drugs to treat MYOCD deficient lung cancers. Our current work shows that loss of function of MYOCD creates Achilles' heels in lung cancer cells, which might be exploited in clinic.

Quantifying Serum Derived Differential Expressed and Low Molecular Weight Protein in Breast Cancer Patients

Background:

Searching the biomarker from complex heterogeneous material for early detection of disease is a challenging task in the field of biomedical sciences.

Objective:

The study has been arranged to explore the proteomics serum derived profiling of the differential expressed and low molecular weight protein in breast cancer patient.

Methods:

Quantitative proteome was analyzed using the Nano LC/Mass and Bioinformatics tool.

Results:

This quantification yields 239 total protein constituting 29% of differentially expressed protein, with 82% downregulated differential protein and 18% up-regulated differential protein. While 12% of total protein were found to be cancer inducing proteins. Gene Ontology (GO) described that the altered proteins with 0-60 kDa mass in nucleus, cytosol, ER, and mitochondria were abundant that chiefly controlled the RNA, DNA, ATP, Ca ion and receptor bindings.

Conclusion:

The study demonstrate that the organelle specific, low molecular weighted proteins are significantly important biomarker. That act as strong agents in the prognosis and diagnosis of breast cancer at early stage.

Molecular insights and cell cycle assessment upon exposure to Chaga (Inonotus obliquus) mushroom polysaccharides in zebrafish (Danio rerio)

Chaga (Inonotus obliquus) mushroom is considered as one of the most powerful antioxidants across the world. Though the therapeutic effects of Chaga components are well characterized in vitro, the in vivo developmental effects are not elucidated in detail. In this study, we assessed the in vivo developmental effects of Chaga polysaccharides in zebrafish, along with revealing the effects on cell cycle and apoptosis. Chaga mushroom polysaccharides comprised xylulose, rhamnose, mannose, glucose, inositol, and galactose, in addition to phenolic compounds; zebrafish embryos exhibited normal embryonic development upon transient exposure to Chaga extract (24 hours). Most embryos (>90%) were found to be healthy even at high concentrations (5 mg/mL). In addition, staining with the DNA binding dye, acridine orange showed that Chaga polysaccharides alleviated oxidative stress. Flow cytometric analysis using H₂DCFDA that specifically binds to cells with fragmented DNA showed significantly reduced levels of intracellular reactive oxygen species (ROS) (p < 0.05), which in turn reduced apoptosis in the developing embryos. Cell cycle analysis by measuring the DNA content using flow cytometry revealed that Chaga polysaccharides moderately arrested the cells at G1 stage, thereby inhibiting cell proliferation that can be further explored in cancer studies. Overall, transient exposure of Chaga polysaccharide extract reduced intracellular ROS and assisted in the normal development of zebrafish.

Highly Expressed FOXF1 Inhibit Non-Small-Cell Lung Cancer Growth via Inducing Tumor Suppressor and G1-Phase Cell-Cycle Arrest

Cancer pathogenesis results from genetic alteration-induced high or low transcriptional programs, which become highly dependent on regulators of gene expression. However, their role in progressive regulation of non-small-cell lung cancer (NSCLC) and how these dependencies may offer opportunities for novel therapeutic options remain to be understood. Previously, we identified forkhead box F1 (FOXF1) as a reprogramming mediator which leads to stemnesss when mesenchymal stem cells fuse with lung cancer cells, and we now examine its effect on lung cancer through establishing lowly and highly expressing FOXF1 NSCLC engineered cell lines. Higher expression of FOXF1 was enabled in cell lines through lentiviral transduction, and their viability, proliferation, and anchorage-dependent growth was assessed. Flow cytometry and Western blot were used to analyze cellular percentage in cell-cycle phases and levels of cellular cyclins, respectively. In mice, tumorigenic behavior of FOXF1 was investigated. We found that FOXF1 was downregulated in lung cancer tissues and cancer cell lines. Cell proliferation and ability of migration, anchorage-independent growth, and transformation were inhibited in H441-FOXF1^H and H1299-FOXF1^H, with upregulated tumor suppressor p21 and suppressed cellular cyclins, leading to cell-cycle arrest at the gap 1 (G1) phase. H441-FOXF1^H and H1299-FOXF1^H injected mice showed reduced tumor size. Conclusively, highly expressing FOXF1 inhibited NSCLC growth via activating tumor suppressor p21 and G1 cell-cycle arrest, thus offering a potentially novel therapeutic strategy for lung cancer.

Bioinformatics Analysis of Global Proteomic and Phosphoproteomic Data Sets Revealed Activation of NEK2 and AURKA in Cancers

Tumor heterogeneity attributes substantial challenges in determining the treatment regimen. Along with the conventional treatment, such as chemotherapy and radiotherapy, targeted therapy has greater impact in cancer management. Owing to the recent advancements in proteomics, we aimed to mine and re-interrogate the Clinical Proteomic Tumor Analysis Consortium (CPTAC) data sets which contain deep scale, mass spectrometry (MS)-based proteomic and phosphoproteomic data sets conducted on human tumor samples. Quantitative proteomic and phosphoproteomic data sets of tumor samples were explored and downloaded from the CPTAC database for six different cancers types (breast cancer, clear cell renal cell carcinoma (CCRCC), colon cancer, lung adenocarcinoma (LUAD), ovarian cancer, and uterine corpus endometrial carcinoma (UCEC)). We identified 880 phosphopeptide signatures for differentially regulated phosphorylation sites across five cancer types (breast cancer, colon cancer, LUAD, ovarian cancer, and UCEC). We identified the cell cycle to be aberrantly activated across these cancers. The correlation of proteomic and phosphoproteomic data sets identified changes in the phosphorylation of 12 kinases with unchanged expression levels. We further investigated phosphopeptide signature across five cancer types which led to the prediction of aurora kinase A (AURKA) and kinases-serine/threonine-protein kinase Nek2 (NEK2) as the most activated kinases targets. The drug designed for these kinases could be repurposed for treatment across cancer types.

MAPK/AP-1 pathway regulates benzidine-induced cell proliferation through the control of cell cycle in human normal bladder epithelial cells

Bladder cancer is the most common malignancy of the urinary tract. Long-term exposure to benzidine is one of the major causes of bladder cancer. However, the mechanism of benzidine-induced bladder cancer is not yet sufficiently characterized. Dysregulated cell proliferation serves a critical role in cancer initiation and development; whether benzidine promotes cell proliferation, and the role of MAPKs in this process, have not previously been investigated. The present study aimed to investigate the benzidine-induced modulation of intracellular mitogen-activated protein kinases (MAPKs) and activator protein-1 (AP-1) signaling cascades on cell proliferation in SV-40 immortalized human uroepithelial cells (SV-HUC-1). It was identified that benzidine exposure enhanced the proliferation of SV-HUC-1 cells, promoted the transition of cells from G1 to S phase and altered the expression level of cell cycle-associated genes at the mRNA and protein levels. Furthermore, exposure of the SV-HUC-1 cells to benzidine was associated with the activation of MAPKs, including extracellular regulated protein kinases 1 and 2, p38 and Jun N-terminal kinase. The downstream target of MAPKs, AP-1 monomers, was also activated. Benzidine-induced proliferation was reversed by MAPK-specific inhibitors. Thus, the present study demonstrated that benzidine enhances the proliferation of bladder cells via activating the MAPK/AP-1 pathway, which may provide novel insights into the molecular mechanisms of benzidine-initiated bladder tumorigenesis, as well as cancer prevention.

Mancozeb selectively induces mitochondrial-mediated apoptosis in human gastric carcinoma cells through ROS generation

Mancozeb (Manganese ethylene bis-dithiocarbamate with zinc salt) is a dithiocarbamate fungicide used to control fungal disease in many fruit plants, flowers and the maintenance of field crops. The effect of mancozeb on cell viability of human gastric adenocarcinoma AGS, SNU-1 cells and human normal FHs 74 Int cells were investigated. This study demonstrated that mancozeb was able to inhibit cell proliferation by 56-82% at 5-10 μM concentrations after 48 h. Mancozeb treatment for 48 h resulted in 33% (P < 0.05) and 61% (P < 0.001) increase in apoptotic cells at 5 and 10 μM concentrations in AGS cells, respectively. Treatment with mancozeb did not cause cell cycle arrest, while modulated the expression level of cleaved caspase-3, and cleavage of poly-(ADP-ribose) polymerase. Furthermore, treatment with mancozeb caused a rapid stimulation of reactive oxygen species (ROS) and loss of mitochondrial transmembrane potential. The results also showed that mancozeb-induced apoptosis was accompanied by up-regulation of Bax and down-regulation of Bcl-2 and Bcl-xL. Overall, our data suggested that mancozeb caused ROS generation which induced significant (P < 0.05) apoptosis in AGS cells that was attenuated with pretreatment of NAC. More importantly, same concentration of mancozeb did not show any considerable effect on cell growth, death, cell cycle arrest and ROS generation in normal FHs 74 Int cells. Overall, for the first time these results suggest that mancozeb has selective anticancer activity at lower concentrations against gastric cancer cells.

Identification of novel gene expression signature in lung adenocarcinoma by using next-generation sequencing data and bioinformatics analysis

Lung adenocarcinoma is one of the leading causes of cancer-related death worldwide. We showed transcriptomic profiles in three pairs of tumors and adjacent non-tumor lung tissues using next-generation sequencing (NGS) to screen protein-coding RNAs and microRNAs. Combined with meta-analysis from the Oncomine and Gene Expression Omnibus (GEO) databases, we identified a representative genetic expression signature in lung adenocarcinoma. There were 9 upregulated genes, and 8 downregulated genes in lung adenocarcinoma. The analysis of the effects from each gene expression on survival outcome indicated that 6 genes (AGR2, SPDEF, CDKN2A, CLDN3, SFN, and PHLDA2) play oncogenic roles, and 7 genes (PDK4, FMO2, CPED1, GNG11, IL33, BTNL9, and FABP4) act as tumor suppressors in lung adenocarcinoma. In addition, we also identified putative genetic interactions, in which there were 5 upregulated microRNAs with specific targets - hsa-miR-183-5p-BTNL9, hsa-miR-33b-5p-CPED1, hsa-miR-429-CPED1, hsa-miR-182-5p-FMO2, and hsa-miR-130b-5p-IL33. These 5 microRNAs have been shown to be associated with tumorigenesis in lung cancer. Our findings suggest that these genetic interactions play important roles in the progression of lung adenocarcinoma. We propose that this molecular change of genetic expression may represent a novel signature in lung adenocarcinoma, which may be developed for diagnostic and therapeutic strategies in the future.

Defining the biological basis of radiomic phenotypes in lung cancer

Medical imaging can visualize characteristics of human cancer noninvasively. Radiomics is an emerging field that translates these medical images into quantitative data to enable phenotypic profiling of tumors. While radiomics has been associated with several clinical endpoints, the complex relationships of radiomics, clinical factors, and tumor biology are largely unknown. To this end, we analyzed two independent cohorts of respectively 262 North American and 89 European patients with lung cancer, and consistently identified previously undescribed associations between radiomic imaging features, molecular pathways, and clinical factors. In particular, we found a relationship between imaging features, immune response, inflammation, and survival, which was further validated by immunohistochemical staining. Moreover, a number of imaging features showed predictive value for specific pathways; for example, intra-tumor heterogeneity features predicted activity of RNA polymerase transcription (AUC = 0.62, p=0.03) and intensity dispersion was predictive of the autodegration pathway of a ubiquitin ligase (AUC = 0.69, p<10-4). Finally, we observed that prognostic biomarkers performed highest when combining radiomic, genetic, and clinical information (CI = 0.73, p<10-9) indicating complementary value of these data. In conclusion, we demonstrate that radiomic approaches permit noninvasive assessment of both molecular and clinical characteristics of tumors, and therefore have the potential to advance clinical decision-making by systematically analyzing standard-of-care medical images.

5-Nitro-5'-hydroxy-indirubin-3'-oxime (AGM130), an indirubin-3'-oxime derivative, inhibits tumor growth by inducing apoptosis against non-small cell lung cancer in vitro and in vivo

This study examined the anti-tumor effects of AGM130, a novel indirubin-3'-oxime derivative in A549 human non-small cell lung cancer cells. AGM130 significantly inhibited the proliferation and arrested the cell cycle of G2/M phase. Induction of apoptosis was detected in AGM130-treated A549 cells. The protein levels of Cytochrome c release, Bax, cleaved caspases and PARP were increased in AGM130 treated cells, whereas Bcl-2 levels were decreased. AGM130 inhibited Insulin-like growth factor 1 receptor (IGF1R), AKT/mTOR signaling and inactivated mitogen-activated protein kinases (MAPK). AGM130 also induced slight autophagy as pro-survival function and autophagy inhibition by chloroquine (CQ) induced necrosis. In vivo tumor xenograft model, AGM130 dose-dependently suppressed transplanted A549 cell tumor growth and induced the expression of proliferative cell nuclear antigen (PCNA). AGM130 also increased TUNEL positive apoptotic cell populations and the induction of glandular differentiation with mucin pool compared with vehicle-treated control in tumor tissue. These results suggest that AGM130 is an effective novel indirubin-3'-oxime derivative of anti-cancer drug and may be an attractive candidate for non-small cell lung cancer therapy.

Clinical outcome and expression of mutant P53, P16, and Smad4 in lung adenocarcinoma: a prospective study

BACKGROUND

Whole-exome sequencing has shown that lung adenocarcinoma (LAC) can be driven by mutant genes, including TP53, P16, and Smad4. The aim of this study was to clarify protein alterations of P53, P16, and Smad4 and to explore their correlations between the protein alterations and clinical outcome.

METHODS

We investigated associations among P53 mutant (P53(Mut)) expression, and P16 and Smad4 loss-of-expression, with clinical outcome in 120 LAC patients who underwent curative resection, using immunohistochemical (IHC) methods.

RESULTS

Of the 120 patients, 76 (63.3%) expressed P53(Mut) protein, whereas 54 (45.0%) loss of P16 expressed and 75 (62.5%) loss of Smad4 expressed. P53(Mut) expression was associated with tumor size (P = 0.041) and pathological stage (P = 0.025). Loss of P16 expression was associated with lymph node metastasis (P = 0.001) and pathological stage (P < 0.001). Loss of Smad4 expression was associated with tumor size (P = 0.033), lymph node metastasis (P = 0.014), pathological stage (P = 0.017), and tumor differentiation (P = 0.022). Kaplan-Meier survival analysis showed that tumor size (P = 0.031), lymph node metastasis (P < 0.001), pathological stage (P < 0.001), P53(Mut) protein expression (P = 0.038), and loss of p16 or Smad4 expression (P < 0.001) were significantly associated with shorter overall survival(OS), whereas multivariate analysis indicated that lymph node metastasis (P = 0.014) and loss of p16 or Smad4 expression (P < 0.001) were independent prognostic factors. Analysis of protein combinations showed patients with more alterations had poorer survival (P < 0.001). Spearman correlation analysis showed that loss of Smad4 expression inversely correlated with expression of P53(Mut) (r = (-)0.196, P = 0.032) and positively with lost P16 expression (r =0.182, P = 0.047).

CONCLUSIONS

The findings indicate that IHC status of P53(Mut), P16, and Smad4 may predict patient outcomes in LAC.

Circulating antibodies to p16 protein-derived peptides in breast cancer

Overexpression of the p16 protein has been reported in breast cancer and may trigger the secretion of antibodies against itself. Circulating anti-p16 antibodies that were detected with a recombinant protein have been reported in breast cancer. The present study was designed to determine whether the levels of circulating IgG antibody to p16 protein-derived linear antigens are altered in breast cancer. An enzyme-linked immunosorbent assay (ELISA) was developed in-house to determine circulating IgG against peptide antigens derived from the p16 protein in 152 female breast cancer patients and 160 healthy female subjects. The Student's T-test revealed that breast cancer patients exhibited significantly higher levels of anti-p16 IgG antibody compared to control subjects (T=2.02, P=0.045). In addition, ductal cancer appeared to be the main type contributing to the increased levels of circulating anti-p16 antibodies (T=2.08, P=0.038). Of all four stages of breast cancer, stage I was associated with the highest levels of IgG antibody (T=2.02, P=0.045) and receiver operating characteristic (ROC) analysis demonstrated that the area under the ROC curve was 0.74 (95% confidence interval: 0.65-083) and that the sensitivity against a specificity of 90% was 30.3%. Therefore, the levels of circulating IgG antibody to the p16 protein may be a potential biomarker for early diagnosis of breast cancer.

Anti-p16 autoantibodies may be a useful biomarker for early diagnosis of esophageal cancer

AIM

Our recent work suggested that circulating IgG antibodies to a linear peptide derived from p16 protein were significantly increased in patients with lung cancer. The present study was then designed to test whether such autoantibodies were also altered in esophageal cancer.

METHODS

An enzyme-linked immunosorbent assay was developed in-house to determine circulating IgA and IgG antibodies against p16 protein-derived antigens in 97 patients with esophageal squamous cell carcinoma (ESCC) and 226 healthy subjects.

RESULTS

The levels of anti-p16 IgG but not IgA antibodies were significantly higher in the patient group than the control group (t = 2.81, P = 0.0052); circulating anti-p16 IgG levels were inversely correlated with stages of ESCC (r = -0.30, df = 81, P = 0.0058) and patients with stage I of ESCC had the highest IgG level among all four stages (t = 5.25, P ≤ 0.0001, compared with control subjects). There was no correlation between the levels of IgA and IgG either in the patient group (r = -0.05, df = 86, P = 0.627) or in the control group (r = -0.1, df = 205, P = 0.146).

CONCLUSION

Circulating IgG autoantibody to p16 protein may be a potential biomarker for early diagnosis of esophageal cancer.

Induction of p21(Waf1/Cip1) by garcinol via downregulation of p38-MAPK signaling in p53-independent H1299 lung cancer

Garcinol, a polyisoprenylated benzophenone, from Garcinia indica fruit rind has possessed anti-inflammatory, antioxidant, antiproliferation, and anticancer activities. However, the anticancer mechanisms of garcinol in lung cancer were still unclear. Therefore, we examine the effects of garcinol on antiproliferation in human lung cancer cells. Treatments with garcinol for 24 h exhibited morphological changes and inhibited the proliferation of H460 (p53-wild type) and H1299 (p53-null) cells in dose- and time-dependent manners. Furthermore, a significant G1 cell cycle arrest was observed in a dose-dependent treatment after H1299 cells were exposed in garcinol, whereas garcinol induced apoptosis rather than cell cycle arrest in H460 cells. Moreover, cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), cyclin D1, and cyclin D3 were decreased, although cyclin E and cyclin-dependent kinase 6 (CDK6) were increased in garcinol-treated H1299 cells. Meanwhile, the protein levels of CDK inhibitors p21(Waf1/Cip1) and p27(KIP1) also exhibited upregulation after garcinol treatments. The enhanced protein-associated level between p21(Waf1/Cip1) and CDK4/2 rather than p27(KIP1) and CDK4/2 was demonstrated in garcinol-treated cells. Additionally, knock-down p21(Waf1/Cip1) by specific siRNA competently prevented garcinol-induced G1 arrest. Besides, garcinol also inhibited ERK and p38-MAPK activations in time-dependent mode. The pretreatment with p38-MAPK inhibitor but not ERK inhibitor raised garcinol-induced G1 population cells. Co-treatment with p38-MAPK inhibitor and garcinol synergistically elevated cyclin E, p21(Waf1/Cip1), and p27(Kip1) expressions. Meanwhile, overexpression dominant negative p38-MAPK also enhanced garcinol-induced p21(Waf1/Cip1) expression in H1299 cells. Accordingly, our data suggested that garcinol induced G1 cell cycle arrest and apoptosis in lung cancer cells under different p53 statuses. The p53-independent G1 cell cycle arrest induced by garcinol might be through upregulation of p21(Waf1/Cip1) triggered from p38-MAPK signaling inactivation.

CASZ1 inhibits cell cycle progression in neuroblastoma by restoring pRb activity

Dysregulation of cell cycle genes such as Cyclin D1 and Chk1 contributes to the undifferentiated phenotype of neuroblastoma (NB). CASZ1 functions as a tumor suppressor in NB; here we sought to determine how loss of CASZ1 contributes to cell cycle dysregulation in NB. CASZ1 restoration in NB cells delays NB cell cycle progression. The earliest changes occur within 8 h of CASZ1 restoration in SY5Y cells with a 2.8-fold increase in the level of p21, an inhibitor of Cdk2/4. By 16 h, there is a 40% decrease in the steady-state levels of Cdk6. Restoration of CASZ1 decreases Cdk2-dependent cyclins A and E protein levels and Cdk4/6-dependent Cyclin D1 protein levels. The restoration of CASZ1 resulted in a decrease in pRb phosphorylation and a significant reduction of E2F transcriptional activity. Subsequent to the changes in the G 1/S transition, induction of CASZ1 results in a decrease in Cyclin B levels and Cdc25c phosphatase levels, an upstream activator of the G 2/M regulator CyclinB:Cdk1. In addition, induction of CASZ1 results in a decrease in the levels of phospho-Chk1, a key M-phase regulatory kinase. Similar results were found in a NB cell line with MYCN amplification. Taken together, this study indicates that restoration of CASZ1 activates pRb in G 1 and inhibits the G 2/M regulators Cyclin B1 and Chk1, leading to a lengthening of NB cell cycle progression and a subsequent decrease in cell proliferation.

Relationship of immunohistochemical biomarker expression and lymph node involvement in patients undergoing surgical treatment of NSCLC with long-term follow-up

We try to identify the relationship between immunohistochemical marker expression and lymph node involvement in a cohort of 282 patients followed for 5 years after curative resection for NSCLC. In 189 patients (67%), lymph nodes were unaffected while 93 patients (33%) showed nodal involvement. The expression of 15 molecular markers was determined from each patient by tissue-array immunohistochemistry. Univariate analysis indicated significantly higher expression of E-cadherin, γ-catenin, p27, and p53 in patients with lymph node involvement. In those with unaffected nodes, p16 and Rb were expressed. E-cadherin expression was related to a 50% mortality reduction in patients with node involvement (hazard ratio (HR) 0.5; p = 0.017). c-erbB-2 expression was correlated with a 3.4-fold increase in mortality compared to patients without expression of this marker in subjects without node involvement (HR 3.41; p = 0.017). Multivariate analysis identified c-erbB-2 (HR 2.22; p = 0.089) and p27 (HR 1.44; p = 0.019) as prognostics of mortality while Rb (HR 0.74) indicated a good prognosis. The expression of proteins encoded by oncogenes and tumor suppressor genes was different according to lymph node involvement. The increased mortality related to c-erbB-2 expression in patients with unaffected lymph nodes would suggests a need for adjuvant treatment.

Nicotine-mediated cell proliferation and tumor progression in smoking-related cancers

Tobacco smoke contains multiple classes of established carcinogens including benzo(a)pyrenes, polycyclic aromatic hydrocarbons, and tobacco-specific nitrosamines. Most of these compounds exert their genotoxic effects by forming DNA adducts and generation of reactive oxygen species, causing mutations in vital genes such as K-Ras and p53. In addition, tobacco-specific nitrosamines can activate nicotinic acetylcholine receptors (nAChR) and to a certain extent β-adrenergic receptors (β-AR), promoting cell proliferation. Furthermore, it has been demonstrated that nicotine, the major addictive component of tobacco smoke, can induce cell-cycle progression, angiogenesis, and metastasis of lung and pancreatic cancers. These effects occur mainly through the α7-nAChRs, with possible contribution from the β-ARs and/or epidermal growth factor receptors. This review article will discuss the molecular mechanisms by which nicotine and its oncogenic derivatives such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and N-nitrosonornicotine induce cell-cycle progression and promote tumor growth. A variety of signaling cascades are induced by nicotine through nAChRs, including the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway, phosphoinositide 3-kinase/AKT pathway, and janus-activated kinase/STAT signaling. In addition, studies have shown that nAChR activation induces Src kinase in a β-arrestin-1-dependent manner, leading to the inactivation of Rb protein and resulting in the expression of E2F1-regulated proliferative genes. Such nAChR-mediated signaling events enhance the proliferation of cells and render them resistant to apoptosis induced by various agents. These observations highlight the role of nAChRs in promoting the growth and metastasis of tumors and raise the possibility of targeting them for cancer therapy.

A novel herbal formula induces cell cycle arrest and apoptosis in association with suppressing the PI3K/AKT pathway in human lung cancer A549 cells

AIM OF THE STUDY

In recent years, the incidence of lung cancer, as well as the mortality rate from this disease, has increased. Moreover, because of acquired drug resistance and adverse side effects, the effectiveness of current therapeutics used for the treatment of lung cancer has decreased significantly. Chinese medicine has been shown to have significant antitumor effects and is increasingly being used for the treatment of cancer. However, as the mechanisms of action for many Chinese medicines are undefined, the application of Chinese medicine for the treatment of cancer is limited. The formula tested has been used clinically by the China National Traditional Chinese Medicine Master, Professor Zhonging Zhou for treatment of cancer. In this article, we examine the efficacy of Ke formula in the treatment of non-small cell lung cancer and elucidate its mechanism of action.

METHODS

A Balb/c nude mouse xenograft model using A549 cells was previously established. The mice were randomly divided into normal, mock, Ke, cisplatin (DDP), and co-formulated (Ke + DDP) groups. After 15 days of drug administration, the animals were sacrificed, body weight and tumor volume were recorded, and the tumor-inhibiting rate was calculated. A cancer pathway finder polymerase chain reaction array was used to monitor the expression of 88 genes in tumor tissue samples. The potential antiproliferation mechanism was also investigated by Western blot analysis.

RESULTS

Ke formula minimized chemotherapy-related weight loss in tumor-bearing mice without exhibiting distinct toxicity. Ke formula also inhibited tumor growth, which was associated with the downregulation of genes in the PI3K/AKT, MAPK, and WNT/β-catenin pathways. The results from Western blot analyses further indicated that Ke blocked the cell cycle progression at the G1/S phase and induced apoptosis mainly via the PI3K/AKT pathway.

CONCLUSION

Ke formula inhibits tumor growth in an A549 xenograft mouse model with no obvious side effects. Moreover, Ke exhibits synergistic antitumor effects when combined with DDP. The mechanism of action of Ke is to induce cell cycle arrest and apoptosis by suppressing the PI3K/AKT pathway. Further research will be required to determine the mechanism of action behind the synergistic effect of Ke and DDP.

How does ethanol induce apoptotic cell death of SK-N-SH neuroblastoma cells

A body of evidence suggests that ethanol can lead to damage of neuronal cells. However, the mechanism underlying the ethanol-induced damage of neuronal cells remains unclear. The role of mitogen-activated protein kinases in ethanol-induced damage was investigated in SK-N-SH neuroblastoma cells. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay, DNA fragmentation detection, and flow cytometric analysis showed that ethanol induced apoptotic cell death and cell cycle arrest, characterized by increased caspase-3 activity, DNA fragmentation, nuclear disruption, and G₁ arrest of cell cycle of the SK-N-SH neuroblastoma cells. In addition, western blot analysis indicated that ethanol induced a lasting increase in c-Jun N-terminal protein kinase activity and a transient increase in p38 kinase activity of the neuroblastoma cells. c-Jun N-terminal protein kinase or p38 kinase inhibitors significantly reduced the ethanol-induced cell death. Ethanol also increased p53 phosphorylation, followed by an increase in p21 tumor suppressor protein and a decrease in phospho-Rb (retinoblastoma) protein, leading to alterations in the expressions and activity of cyclin dependent protein kinases. Our results suggest that ethanol mediates apoptosis of SK-N-SH neuroblastoma cells by activating p53-related cell cycle arrest possibly through activation of the c-Jun N-terminal protein kinase-related cell death pathway.

Interleukin-5 enhances the migration and invasion of bladder cancer cells via ERK1/2-mediated MMP-9/NF-κB/AP-1 pathway: involvement of the p21WAF1 expression

Inflammatory cytokines may be a critical component of epithelial cancer progression. We examined the role of interleukin (IL)-5 in the migration of bladder cancer cells. The expression of IL-5 and its receptor IL-5Rα was enhanced in patients with muscle invasive bladder cancers (MIBC), and then it was detected in bladder cancer cell lines 5637 and T-24. IL-5 increased migration and MMP-9 expression via activation of transcription factors NF-κB and AP-1, and induced activation of ERK1/2 and Jak-Stat signaling in both cells. Treatment with ERK1/2 inhibitor U0126 significantly inhibited induction of migration, MMP-9 expression, and activation of NF-κB and AP-1 in IL-5-treated cells. However, none of the Jak inhibitors affected the IL-5-induced migration of bladder cancer cells. Moreover, gene knockdown for IL-5Rα, using siRNA transfection, suppressed migration, ERK1/2 activation, MMP-9 expression, as well as the binding activation of NF-κB and AP-1 in IL-5-treated bladder cancer cells. Similar results were observed in βc siRNA (si-βc) transfected cells. Unexpectedly, IL-5 treatment resulted in significant induction of p21WAF1 in both cell lines. The p21WAF1-specific small interfering RNA inhibited IL-5-induced cell migration, ERK activity, MMP-9 expression, and activation of NF-κB and AP-1 in bladder cancer cells. The effects of IL-5-induced cell responses were confirmed by transfection of IL-5 gene, which demonstrated that p21WAF1 participates in the induction of cell migration, leading to an increase in ERK1/2-mediated MMP-9 expression through activation of NF-κB and AP-1 in IL-5-treated bladder cancer cells. These unexpected results provide a theoretical basis for the therapeutic targeting of IL-5 in bladder cancer.

Interleukin-20 promotes migration of bladder cancer cells through extracellular signal-regulated kinase (ERK)-mediated MMP-9 protein expression leading to nuclear factor (NF-κB) activation by inducing the up-regulation of p21(WAF1) protein expression

The role of inflammatory cytokine interleukin-20 (IL-20) has not yet been studied in cancer biology. Here, we demonstrated up-regulation of both IL-20 and IL-20R1 in muscle-invasive bladder cancer patients. The expressions of IL-20 and IL-20R1 were observed in bladder cancer 5637 and T-24 cells. We found that IL-20 significantly increased the expression of matrix metalloproteinase (MMP)-9 via binding activity of NF-κB and AP-1 in bladder cancer cells and stimulated the activation of ERK1/2, JNK, p38 MAPK, and JAK-STAT signaling. Among the pathways examined, only ERK1/2 inhibitor U0126 significantly inhibited IL-20-induced migration and invasion. Moreover, siRNA knockdown of IL-20R1 suppressed migration, invasion, ERK1/2 activation, and NF-κB-mediated MMP-9 expression induced by IL-20. Unexpectedly, the cell cycle inhibitor p21(WAF1) was induced by IL-20 treatment without altering cell cycle progression. Blockade of p21(WAF1) function by siRNA reversed migration, invasion, activation of ERK signaling, MMP-9 expression, and activation of NF-κB in IL-20-treated cells. In addition, IL-20 induced the activation of IκB kinase, the degradation and phosphorylation of IκBα, and NF-κB p65 nuclear translocation, which was regulated by ERK1/2. IL-20 stimulated the recruitment of p65 to the MMP-9 promoter region. Finally, the IL-20-induced migration and invasion of cells was confirmed by IL-20 gene transfection and by addition of anti-IL-20 antibody. This is the first report that p21(WAF1) is involved in ERK1/2-mediated MMP-9 expression via increased binding activity of NF-κB, which resulted in the induction of migration in IL-20/IL-20R1 dyad-induced bladder cancer cells. These unexpected results might provide a critical new target for the treatment of bladder cancer.

Association of p21 Ser31Arg and p53 Arg72Pro polymorphisms with lung cancer risk in CAPUA study

BACKGROUND

The aim of this study was to investigate how Ser31Arg polymorphisms in p21 may modify lung cancer susceptibility. Because p21 is the major downstream mediator of p53, we analyzed the combined effect of two polymorphisms, p21 Ser31Arg and TP53 Arg72Pro, to elucidate whether polymorphic variants determine the risk of lung cancer.

METHODS

This was designed as a hospital-based case-control study, and included 675 cases and 675 control subjects matched by ethnicity, gender, and age. Genotypes were determined by polymerase chain reaction restriction fragment length polymorphism, and multivariate unconditional logistic regression was performed to analyze the results.

RESULTS

Subjects who carried the p21 Ser31Arg allele had a higher risk of lung cancer (adjusted odds ratio [OR] 1.38; 95% confidence interval [CI] 0.99-2.03). This risk was increased in men aged younger than 55 years (adjusted OR 2.35; 95% CI 1.00-5.51). Smokers had an increased risk of lung cancer (adjusted OR 2.23; 95% CI 1.24-4.02). Men younger than 55 years carrying risk alleles for both genes (p21 Ser31Arg and TP53 Arg72Pro) had an increased risk (adjusted OR 5.78; 95% CI 1.38-24.19), as did smokers with both risk alleles (adjusted OR 4.52; 95% CI 1.52-13.50).

CONCLUSION

The presence of both variant alleles increased the risk of developing lung cancer in men, particularly in smokers younger than 55 years.

Inhibitory effects of trehalose on malignant melanoma cell growth: implications for a novel topical anticancer agent on the ocular surface

Purpose. To investigate the inhibitory effects of trehalose on malignant melanoma cell growth. Methods. We cultured human malignant melanoma cells in a medium containing trehalose (control/2.5%/5.0%/7.5%/10.0%) and used the MTT assay to evaluate the growth activities. Subsequently, trehalose was topically instilled on subconjunctivally inoculated melanoma cells in F334/NJcl-rmu/rmu rats, followed by a histopathological evaluation of tumor growth. Using flow cytometry, we compared the distribution of the cell cycle, rate of apoptotic cells, and intracellular factors related to the cell cycle in cultured melanoma cells after trehalose treatment. Results. The MTT study showed that proliferation of melanoma cells was significantly inhibited by ≧ 5% of trehalose concentrations in the culture media. Subconjunctivally inoculated melanoma cell masses were significantly smaller in eyes administered trehalose as compared to controls. Flow cytometry analyses demonstrated that the trehalose groups had increased rates of G2/M phase cells and apoptotic cells in the cell culture. These cells also exhibited increased expressions of cell-cycle inhibitory factors. Conclusions. The current results show trehalose inhibits malignant melanoma cell growth by inducing G2/M cell cycle arrest and apoptosis, suggesting trehalose as a potential candidate for a topical agent to inhibit proliferation of malignant tumor cells of the ocular surface.

Threshold dose of liver tumor promoting effect of β-naphthoflavone in rats

To determine the threshold dose of β-Naphthoflavone (BNF) that induces hepatocellular tumor promoting effects, reactive oxygen species (ROS) generation and thiobarbituric acid-reactive substance (TBARS) formation, and drug-metabolizing enzymes that protect against ROS generation, two-stage liver carcinogenesis model was used. Partial hepatectomized rats (n = 11 to 12) were fed diets containing 0, 0.03, 0.06, 0.125 or 0.25% BNF for 6 weeks after an intraperitoneal injection of N-diethylnitrosamine (DEN) to initiate hepatocarcinogenesis. Histopathologically, glutathione S-transferase placental form (GST-P)-positive foci significantly increased in rats given 0.25% BNF. No marked changes in ROS production and TBARS contents were observed between the BNF treated and DEN alone groups. Real-time RT-PCR showed that the expression of Cyp1a1, Cyp1a2, Cyp1b1 and Nqo1 significantly increased in the groups given 0.03% BNF or more, but Ugt1a6, Akr7a3 and Gstm1 significantly increased in the groups given 0.125% BNF or more. Gpx2 and Yc2 significantly increased in the groups given 0.06% BNF or more and 0.25% BNF, respectively. Inflammation-related genes such as Ccl2, Mmp12, Serpine1 and Cox-2 significantly increased in the 0.25% BNF group. In immunohistochemistry, the number of cyclooxygenase-2 (COX-2)-positive cells increased in rats given 0.25% BNF. These results suggest that 0.25% BNF is the threshold dose for liver tumor promotion, and the fact that inflammation-related genes and COX-2 protein increased in the 0.25% BNF group strongly suggests that inflammation is involved in the liver tumor promoting effect of BNF in rats.