LOX family and ZFPM2 as novel diagnostic biomarkers for malignant pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare and aggressive cancer that develops in the pleural and outer layer of tissues surrounding the lungs. MPM is primarily caused by occupational exposure to asbestos and results in a poor prognosis. Effective therapeutics as well as early diagnostics for the MPM are still lacking. To identify potential diagnostic biomarkers for MPM, we performed bioinformatics analysis of public database. METHODS: Utilizing databases from Cancer Cell Line Encyclopedia (CCLE) and Gene Expression Omnibus (GEO), we identified several potential candidates that could act as MPM biomarkers. We carried out additional molecular analyses of these potential markers using MPM patient tissue samples via quantitative polymerase chain reaction. RESULTS: We identified Lysyl oxidase (LOX), Lysyl oxidase homologs 1&2 (LOXL1& LOXL2) Zinc Finger Protein, FOG Family Member 2 (ZFPM2) as potential diagnostic biomarkers for MPM. In this study, we found that the LOX family and ZFPM2 showed comparable diagnostic ability to Fibulin-3 or mesothelin (MSLN) and would be better potential biomarkers than Sulfatase 1 (SULF1), Thrombospondin 2 (THBS2) and Cadherin 11 (CDH11). CONCLUSIONS: LOX family and ZPFM2 were identified as novel MPM diagnostic biomarkers which could strengthen MPM clinical diagnostic capabilities.

Correction: PPARγ sumoylation-mediated lipid accumulation in lung cancer.

[This corrects the article DOI: 10.18632/oncotarget.19700.].

Inhibition of oncogenic Src induces FABP4-mediated lipolysis via PPARγ activation exerting cancer growth suppression.

BACKGROUND: c-Src is a driver oncogene well-known for tumorigenic signaling, but little for metabolic function. Previous reports about c-Src regulation of glucose metabolism prompted us to investigate its function in other nutrient modulation, particularly in lipid metabolism. METHODS: Oil-red O staining, cell growth assay, and tumor volume measurement were performed to determine lipid amount and growth inhibitory effect of treatments in lung cancer cells and xenograft model. Gene expression was evaluated by immunoblotting and relative RT-PCR. Transcriptional activity of peroxisome proliferator-activated receptor gamma (PPARγ) was assessed by luciferase assay. Reactive oxygen species (ROS) was measured using ROS sensing dye. Oxygen consumption rate was evaluated by Seahorse XF Mito Stress Test. Clinical relevance of candidate proteins was examined using patient samples and public database analysis. FINDINGS: Inhibition of Src induced lipolysis and increased intracellular ROS. Src inhibition derepressed PPARγ transcriptional activity leading to induced expression of lipolytic gene fatty acid binding protein (FABP) 4 which accompanies reduced lipid droplets and decreased tumor growth. The reverse correlation of Src and FABP4 was confirmed in pair-matched lung cancer patient samples, and further analysis using public datasets revealed upregulation of lipolytic genes is associated with better prognosis of cancer patients. INTERPRETATION: This study provides an insight of how oncogenic factor Src concurrently regulates both cellular signaling pathways and metabolic plasticity to drive cancer progression. FUND: National Research Foundation of Korea and Korea Health Industry Development Institute.

PPARγ sumoylation-mediated lipid accumulation in lung cancer.

Metabolic reprogramming as a crucial emerging hallmark of cancer is critical for tumor cells to maintain cellular bioenergetics, biosynthesis and reduction/oxidation (REDOX) balance. Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear hormone receptor regulating transcription of diverse gene sets involved in inflammation, metabolism, and suppressing tumor growth. Thiazolidinediones (TZDs), as selective PPARγ ligands, are insulin-sensitizing drugs widely prescribed for type 2 diabetic patients in the clinic. Here, we report that sumoylation of PPARγ couples lipid metabolism to tumor suppressive function of the receptor in lung cancer. We found that ligand activation of PPARγ dramatically induced de novo lipid synthesis as well as fatty acid beta (ß)-oxidation in lung cancer both in vitro and in vivo. More importantly, it turns out that PPARγ regulation of lipid metabolism was dependent on sumoylation of PPARγ. Further biochemical analysis revealed that PPARγ-mediated lipid synthesis depletes nicotinamide adenine dinucleotide phosphate (NADPH), consequently resulting in increased mitochondrial reactive oxygen species (ROS) level that subsequently disrupted REDOX balance in lung cancer. Therefore, liganded PPARγ sumoylation is not only critical for cellular lipid metabolism but also induces oxidative stress that contributes to tumor suppressive function of PPARγ. This study provides an important insight of future translational and clinical research into targeting PPARγ regulation of lipid metabolism in lung cancer patients accompanying type 2 diabetes.

Gallic acid inhibition of Src-Stat3 signaling overcomes acquired resistance to EGF receptor tyrosine kinase inhibitors in advanced non-small cell lung cancer.

Tyrosine kinase inhibitors (TKIs) targeting epidermal growth factor receptor (EGFR) have clinically benefited to lung cancer patients harboring a subset of activating EGFR mutations. However, even with the remarkable therapeutic response at the initial TKI treatment, most lung cancer patients eventually have relapsed aggressive tumors due to acquired resistance to the TKIs. Here, we report that 3, 4, 5-trihydroxybenzoic acid or gallic acid (GA), a natural polyphenolic compound, shows anti-tumorigenic effects in TKI-resistant non-small cell lung cancer (NSCLC). Using both in vitro growth assay and in vivo xenograft animal model, we demonstrated tumor suppressive effect of GA was more selective for the TKI-resistant cancer compared to the TKI-sensitive one. Mechanistically, GA treatment inhibited Src-Stat3-mediated signaling and decreased the expression of Stat3-regulated tumor promoting genes, subsequently inducing apoptosis and cell cycle arrest in the TKI-resistant lung cancer but not in the TKI-sensitive one. Consistent with the in vitro results, in vivo xenograft experiments showed the TKI-resistant tumor-selective growth inhibition and suppression of Src-Stat3-dependent signaling in the GA-treated tumors isolated from the xenograft model. This finding identified an importance of Src-Stat3 signaling cascade in GA-mediated tumor-suppression activity and, more importantly, provides a novel therapeutic insight of GA for advanced TKI-resistant lung cancer.

Nuclear Receptor Expression and Function in Human Lung Cancer Pathogenesis.

Lung cancer is caused by combinations of diverse genetic mutations. Here, to understand the relevance of nuclear receptors (NRs) in the oncogene-associated lung cancer pathogenesis, we investigated the expression profile of the entire 48 NR members by using QPCR analysis in a panel of human bronchial epithelial cells (HBECs) that included precancerous and tumorigenic HBECs harboring oncogenic K-rasV12 and/or p53 alterations. The analysis of the profile revealed that oncogenic alterations accompanied transcriptional changes in the expression of 19 NRs in precancerous HBECs and 15 NRs according to the malignant progression of HBECs. Amongst these, peroxisome proliferator-activated receptor gamma (PPARγ), a NR chosen as a proof-of-principle study, showed increased expression in precancerous HBECs, which was surprisingly reversed when these HBECs acquired full in vivo tumorigenicity. Notably, PPARγ activation by thiazolidinedione (TZD) treatment reversed the increased expression of pro-inflammatory cyclooxygenase 2 (COX2) in precancerous HBECs. In fully tumorigenic HBECs with inducible expression of PPARγ, TZD treatments inhibited tumor cell growth, clonogenecity, and cell migration in a PPARγ-sumoylation dependent manner. Mechanistically, the sumoylation of liganded-PPARγ decreased COX2 expression and increased 15-hydroxyprostaglandin dehydrogenase expression. This suggests that ligand-mediated sumoylation of PPARγ plays an important role in lung cancer pathogenesis by modulating prostaglandin metabolism.

Insulin priming effect on estradiol-induced breast cancer metabolism and growth.

Diabetes is a risk factor for breast cancer development and is associated with poor prognosis for breast cancer patients. However, the molecular and biochemical mechanisms underlying the association between diabetes and breast cancer have not been fully elucidated. Here, we investigated estradiol response in MCF-7 breast cancer cells with or without chronic exposure to insulin. We found that insulin priming is necessary and specific for estradiol-induced cancer cell growth, and induces anaplerotic shunting of glucose into macromolecule biosynthesis in the estradiol treated cells. Treatment with ERK or Akt specific inhibitors, U0126 or LY294002, respectively, suppressed estradiol-induced growth. Interestingly, molecular analysis revealed that estradiol treatment markedly increases expression of cyclin A and B, and decreases p21 and p27 in the insulin-primed cells. In addition, estradiol treatment activated metabolic genes in pentose phosphate (PPP) and serine biosynthesis pathways in the insulin-primed cells while insulin priming decreased metabolic gene expression associated with glucose catabolism in the breast cancer cells. Finally, we found that anti-diabetic drug metformin and AMPK ligand AICAR, but not thiazolidinediones (TZDs), specifically suppress the estradiol-induced cellular growth in the insulin-primed cells. These findings suggest that estrogen receptor (ER) activation under chronic hyperinsulinemic condition increases breast cancer growth through the modulation of cell cycle and apoptotic factors and nutrient metabolism, and further provide a mechanistic evidence for the clinical benefit of metformin use for ER-positive breast cancer patients with diabetes.

Combined therapeutic potential of nuclear receptors with receptor tyrosine kinase inhibitors in lung cancer.

Cancer heterogeneity is a big hurdle in achieving complete cancer treatment, which has led to the emergence of combinational therapy. In this study, we investigated the potential use of nuclear receptor (NR) ligands for combinational therapy with other anti-cancer drugs. We first profiled all 48 NRs and 48 biological anti-cancer targets in four pairs of lung cell lines, where each pair was obtained from the same patient. Two sets of cell lines were normal and the corresponding tumor cell lines while the other two sets consisted of primary versus metastatic tumor cell lines. Analysis of the expression profile revealed 11 NRs and 15 cancer targets from the two pairs of normal versus tumor cell lines, and 9 NRs and 9 cancer targets from the primary versus metastatic tumor cell lines had distinct expression patterns in each category. Finally, the evaluation of nuclear receptor ligand T0901317 for liver X receptor (LXR) demonstrated its combined therapeutic potential with tyrosine kinase inhibitors. The combined treatment of cMET inhibitor PHA665752 or EGFR inhibitor gefitinib with T0901317 showed additive growth inhibition in both H2073 and H1993 cells. Mechanistically, the combined treatment suppressed cell cycle progression by inhibiting cyclinD1 and cyclinB expression. Taken together, this study provides insight into the potential use of NR ligands in combined therapeutics with other biological anti-cancer drugs.

Repression of human telomerase reverse transcriptase using artificial zinc finger transcription factors.

Telomerase activation is a key step in the development of human cancers. Expression of the catalytic subunit, human telomerase reverse transcriptase (hTERT), represents the limiting factor for telomerase activity. In this study, we have used artificial zinc finger protein (ZFP) transcription factors (TF) to repress the expression of hTERT in human cancer cell lines at the transcriptional level. We have constructed four-fingered ZFPs derived from the human genome which binds 12-bp recognition sequences within the promoter of the hTERT gene and fused them with a KRAB repressor domain to create a potent transcriptional repressor. Luciferase activity was decreased by >80% in all of the transcriptional repressors with luciferase reporter assay. When they were transfected into the telomerase-positive HEK293 cell line, a decrease of mRNA level and telomerase activity together with shortening of telomere length was observed. Actual growth of HEK293 cells was also inhibited by transfection of artificial ZFP-TFs. The repression was maintained for 100 days of culture. The repression of telomerase expression by artificial ZFP-TFs targeting the promoter region of the hTERT presents a new promising strategy for inhibiting the growth of human cancer cells.

Systematic probing of an atomic charge set of sialic acid disaccharides for the rational molecular modeling of avian influenza virus based on molecular dynamics simulations.

A systematic searching approach for an atomic charge set through molecular dynamics simulations is introduced to calculate a reasonable sialic acid carbohydrate conformation with respect to the experimentally observed structures. The present molecular dynamics simulation study demonstrated that B3LYP/6-31G is the most suitable basis set for the sialic acid disaccharides, attaining good agreement with experimental data.

Predictive factors for interferon and ribavirin combination therapy in patients with chronic hepatitis C.

AIM: To confirm the predictive factors for interferon (IFN)-alpha and ribavirin combination therapy for chronic hepatitis patients with hepatitis C virus (HCV) genotype 1b. METHODS: HCV RNA from 50 patients infected with HCV genotype 1b was studied by cloning and sequencing of interferon sensitivity determining region (ISDR), PKR-eIF2alpha phosphorylation homology domain (PePHD). Patients were treated with IFN-alpha and ribavirin for 6 mo and grouped by effectiveness of the therapy. A variety of factors were analyzed. RESULTS: Our data showed that age, HCV RNA titer, and ISDR type could be used as the predictive factors for combined IFN-alpha and ribavirin efficacy. Characteristically, mutations in PePHD appeared only when the combination therapy was effective. Other factors, such as sex and alanine aminotransferase (ALT) level, were not related to its efficacy. Adjusting for age and HCV RNA titer indicated that the ISDR type was the most potent predictive factor. CONCLUSION: HCV RNA ISDR type is an important factor for predicting efficacy of IFN-alpha and ribavirin combination therapy in Korean patients.

Anti-diabetic effect of alkaline-reduced water on OLETF rats.

Alkalin-reduced water (ARW) is known to exert several anti-cancer effects, as well as to scavenge reactive oxygen species (ROS) and reduce blood-glucose levels. This study was performed in order to determine the effects of ARW on the control of spontaneous diabetes in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. We assigned 16 male OLETF rats (4 wk) to two groups: an experimental group, which was given ARW, and a control group, which received laboratory tap water. From week 6 to 32, the body weight, lipid composition, and glucose levels in the blood of the rats were measured. The glucose levels of both groups tended to increase. However, the ARW group's glucose levels were significantly lower than those of the control group after 12 weeks (p<0.05). The total cholesterol and triglyceride levels in the ARW group were found to be significantly lower than those of the control group during the experimental period. These results suggest that ARW spurred the growth of OLETF rats during the growth stage, and that long-term ingestion of ARW resulted in a reduction in the levels of glucose, triglycerides, and total cholesterol in the blood.

Characteristic of aromatic amino acid substitution at alpha 96 of hemoglobin.

Replacement of valine by tryptophan or tyrosine at position alpha96 of the alpha chain (alpha96Val), located in the alpha(1)beta(2) subunit interface of hemoglobin leads to low oxygen affinity hemoglobin, and has been suggested to be due to the extra stability introduced by an aromatic amino acid at the alpha96 position. The characteristic of aromatic amino acid substitution at the alpha96 of hemoglobin has been further investigated by producing double mutant r Hb (alpha42Tyr --> Phe, alpha96Val --> Trp). r Hb (alpha42Tyr --> Phe) is known to exhibit almost no cooperativity in binding oxygen, and possesses high oxygen affinity due to the disruption of the hydrogen bond between alpha42Tyr and beta99Asp in thealpha(1)beta(2) subunit interface of deoxy Hb A. The second mutation, alpha96Val -->Trp, may compensate the functional defects of r Hb (alpha42Tyr --> Phe), if the stability due to the introduction of trypophan at the alpha 96 position is strong enough to overcome the defect of r Hb (alpha42Tyr --> Phe). Double mutant r Hb (alpha42Tyr --> Phe, alpha96Val --> Trp) exhibited almost no cooperativity in binding oxygen and possessed high oxygen affinity, similarly to that of r Hb (alpha42Tyr --> Phe). (1)H NMR spectroscopic data of r Hb (alpha42Tyr --> Phe, alpha96Val --> Trp) also showed a very unstable deoxy-quaternary structure. The present investigation has demonstrated that the presence of the crucible hydrogen bond between alpha 42Tyr and beta 99Asp is essential for the novel oxygen binding properties of deoxy Hb (alpha96Val --> Trp) .

Human zinc fingers as building blocks in the construction of artificial transcription factors.

We describe methods for generating artificial transcription factors capable of up- or downregulating the expression of genes whose promoter regions contain the target DNA sequences. To accomplish this, we screened zinc fingers derived from sequences in the human genome and isolated 56 zinc fingers with diverse DNA-binding specificities. We used these zinc fingers as modular building blocks in the construction of novel, sequence-specific DNA-binding proteins. Fusion of these zinc-finger proteins with either a transcriptional activation or repression domain yielded potent transcriptional activators or repressors, respectively. These results show that the human genome encodes zinc fingers with diverse DNA-binding specificities and that these domains can be used to design sequence-specific DNA-binding proteins and artificial transcription factors.

Monte Carlo docking simulations of cyclomaltoheptaose and dimethyl cyclomaltoheptaose with paclitaxel.

The molecular basis for the remarkable enhancement of the solubility of paclitaxel by O-dimethylcyclomaltoheptaose (DM-beta-CD) over cyclomaltoheptaose (beta-cyclodextrin, beta-CD) was investigated with Monte Carlo docking-minimization simulation. As possible guests of inclusion complexation for the host cyclic oligosaccharides, two functional moieties of the suggested solution structure of paclitaxel were used where one is the C-3'N benzoyl moiety (B-ring) and the other is a hydrophobic (HP) cluster site among the C-3' phenyl (C-ring), C-2 benzoate (A-ring), and C-4 acetoxy moieties. The energetic preference of inclusion complexation of DM-beta-CD over beta-CD was analyzed on the basis of more efficient partitioning process of DM-beta-CD into the hydrophobic cluster site of the paclitaxel.

Factors predictive of response to interferon-alpha therapy in hepatitis C virus type 1b infection.

Interferon-alpha (IFN-alpha) has been used to treat hepatitis C Virus (HCV)-induced infection but has been effective in only about half of all patients. It is suggested that the different responses to IFN-alpha treatment in HCV infection may be influenced by HCV genotypes, HCV RNA titer at the beginning of IFN-alpha therapy, and the sequences of the interferon sensitivity determining region (ISDR). However, there have also been reports showing that these have no relation to an IFN-alpha effect. In a previous study, it was found that the nucleotide sequence variation in the hypervariable region (HVR) 1 of the HCV could predict the effect of IFN-alpha. In the present investigation, an attempt was made to determine the predictive factors of IFN-alpha therapy. Twenty-six patients with HCV infection were treated with IFN-alpha. Among these, 13 patients recovered after 3 to 6 months of IFN-alpha treatment, although the other 13 patients showed no response after 6 months of treatment with IFN-alpha. In order to determine the predictive factors of IFN-alpha therapy, the ALT levels, HCV genotypes, HCV serum titer, and the quasispecies of HVR 1 were compared between responders and non-responders. It is suggested that the variation in the HVR 1 and HCV serum titer can be used to predict the effect of IFN-alpha.