Prostate Cancer Associated Lipid Signatures in Serum Studied by ESI-Tandem Mass Spectrometryas Potential New Biomarkers

Prostate cancer (PCa) is one amongst the most common cancersin western men. Incidence rate ofPCa is on the rise worldwide. The present study deals with theserum lipidome profiling of patients diagnosed with PCa to identify potential new biomarkers. We employed ESI-MS/MS and GC-MS for identification of significantly altered lipids in cancer patient’s serum compared to controls. Lipidomic data revealed 24 lipids are significantly altered in cancer patinet’s serum (n = 18) compared to normal (n = 18) with no history of PCa. By using hierarchical clustering and principal component analysis (PCA) we could clearly separate cancer patients from control group. Correlation and partition analysis along with Formal Concept Analysis (FCA) have identified that PC (39:6) and FA (22:3) could classify samples with higher certainty. Both the lipids, PC (39:6) and FA (22:3) could influence the cataloging of patients with 100% sensitivity (all 18 control samples are classified correctly) and 77.7% specificity (of 18 tumor samples 4 samples are misclassified) with p-value of 1.612×10⁻⁶ in Fischer’s exact test. Further, we performed GC-MS to denote fatty acids altered in PCa patients and found that alpha-linolenic acid (ALA) levels are altered in PCa. We also performed an in vitro proliferation assay to determine the effect of ALA in survival of classical human PCa cell lines LNCaP and PC3. We hereby report that the altered lipids PC (39:6) and FA (22:3) offer a new set of biomarkers in addition to the existing diagnostic tests that could significantly improve sensitivity and specificity in PCa diagnosis.

Investigation of triazole-linked indole and oxindole glycoconjugates as potential anticancer agents: novel Akt/PKB signaling pathway inhibitors

Novel triazole-linked indole and oxindole glycoconjugates as inhibitors of the Akt/PKB signaling pathway.

Synthesis and evaluation of novel fluorinated pyrazolo-1,2,3-triazole hybrids as antimycobacterial agents

A library of novel 3-trifluoromethyl pyrazolo-1,2,3-triazole hybrids (5-7) were accomplished starting from 5-phenyl-3-(trifluoromethyl)-1H-pyrazol-4-amine (1) via key intermediate 2-azido-N-(5-phenyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)acetamide (3) through click chemistry approach. Thus obtained compounds in 5-7 series were evaluated for in vitro antimycobacterial activity against Mycobacterium smegmatis (MC(2) 155) and also verified the cytotoxicity. These studies engendered promising lead compounds 5q, 7b and 7c with MIC (μg/mL) values 15.34, 16.18 and 16.60, respectively. Amongst these three compounds, 2-(4-(4-methoxybenzoyl)-1H-1,2,3-triazol-1-yl)-N-(5-phenyl-3-(trifluoromethyl)-1H-pyrazol-4-yl) acetamide (5q) emerged as the most promising antitubercular agent with lowest cytotoxicity against the A549 cancer cell line. This is the first report to demonstrate the pyrazolo triazole hybrids as potential antimycobacterial agents.

Synthesis and biological screening of 2'-aryl/benzyl-2-aryl-4-methyl-4',5-bithiazolyls as possible anti-tubercular and antimicrobial agents

A series of 2'-aryl/benzyl-2-aryl-4-methyl-4',5-bithiazolyl derivatives, 25-64 were synthesized and evaluated for inhibitory activity against Mycobacterium smegmatis MC(2) 155 strain and antimicrobial activities against four pathogenic bacteria Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Proteus vulgaris. Among them, compounds 40, 49, 50, and 54 exhibited moderate to good inhibition on the growth of the bacteria Mycobacterium smegmatis at the concentration of 30 μM. Compounds 26, 40, 44, 54 and 56 exhibited moderate to good antibacterial activity. Compound 5-(2'-(4-fluorobenzyl)thiazol-4'-yl)-2-(4-fluorophenyl)-4-methyl-thiazole (54) exhibited both antitubercular as well as antimicrobial activity against all tested strains.

Synthesis, in vitro anticancer and antimycobacterial evaluation of new 5-(2,5-dimethoxyphenyl)-1,3,4-thiadiazole-2-amino derivatives

A series of 2,5-disubstituted-1,3,4-thiadiazole derivatives 5a-5l, 7a-7e and 9 have been synthesised and screened for in vitro antimycobacterial activity against Mycobacterium smegmatis MC-155. In addition these compounds have also been screened for cytotoxic activity against cancer cell lines HT-29, MDA-MB-231 by MTT colorimetric assay. The compounds are well characterized by spectral analysis viz. (1)H NMR, (13)C NMR, FT-IR, mass and HRMS. Screening results indicate that compounds 5g, 7a possess good antitubercular activity with MIC value 65.74 and 40.86, respectively, compounds 5g, 7a, 7b, 7d, 7e and 9 displayed promising cytotoxic activity against the cell lines tested. 5g and 7a stand out to be potent antimycobacterial and anticancer agents among the tested series. Further the title compounds were also tested on human normal cells HEK293T and are found to be safer with lesser cytotoxicity. It is interesting to observe that compound 5g has come out to be safer, potent anticancer and antimycobacterial agent.

Mechanical stress enhances CD9 expression in cultured podocytes

Elevated glomerular pressure represents a high risk for the development of severe kidney diseases and causes an increase in mechanical load to podocytes. In this study, we investigated whether mechanical stress alters gene expression in cultured podocytes using gene arrays. We found that tetraspanin CD9 is significantly upregulated in cultured podocytes after mechanical stress. The differential expression of CD9 was confirmed by RT-PCR and Western blotting under stretched and unstretched conditions. Furthermore, mechanical stress resulted in a relocalization of CD9. To get an insight into the functional role of CD9, podocytes were transfected with pEGFP-CD9. The expression of CD9 induced the formation of substratum-attached thin arborized protrusions. Ca(2+) depletion revealed that podocytes overexpressing CD9 possess altered adhesive properties in contrast to the control transfected cells. Finally, elevated CD9 expression increased migration of podocytes in a wound assay. In summary, our results suggest that upregulation of CD9 may play an important role in podocyte morphology, adhesion, and migration.

Fluvastatin mediated breast cancer cell death: a proteomic approach to identify differentially regulated proteins in MDA-MB-231 cells

Statins are increasingly being recognized as anti-cancer agents against various cancers including breast cancer. To understand the molecular pathways targeted by fluvastatin and its differential sensitivity against metastatic breast cancer cells, we analyzed protein alterations in MDA-MB-231 cells treated with fluvastatin using 2-DE in combination with LC-MS/MS. Results revealed dys-regulation of 39 protein spots corresponding to 35 different proteins. To determine the relevance of altered protein profiles with breast cancer cell death, we mapped these proteins to major pathways involved in the regulation of cell-to-cell signaling and interaction, cell cycle, Rho GDI and proteasomal pathways using IPA analysis. Highly interconnected sub networks showed that vimentin and ERK1/2 proteins play a central role in controlling the expression of altered proteins. Fluvastatin treatment caused proteolysis of vimentin, a marker of epithelial to mesenchymal transition. This effect of fluvastatin was reversed in the presence of mevalonate, a downstream product of HMG-CoA and caspase-3 inhibitor. Interestingly, fluvastatin neither caused an appreciable cell death nor did modulate vimentin expression in normal mammary epithelial cells. In conclusion, fluvastatin alters levels of cytoskeletal proteins, primarily targeting vimentin through increased caspase-3- mediated proteolysis, thereby suggesting a role for vimentin in statin-induced breast cancer cell death.

Statin‐induced inhibition of breast cancer proliferation and invasion involves attenuation of iron transport: intermediacy of nitric oxide and antioxidant defence mechanisms

Accumulating evidence from in vitro, in vivo, clinical and epidemiological studies shows promising results for the use of statins against many cancers including breast carcinoma. However, the molecular mechanisms responsible for the anti‐proliferative and anti‐invasive properties of statins still remain elusive. In this study, we investigated the involvement of nitric oxide, iron homeostasis and antioxidant defence mechanisms in mediating the anti‐proliferative and anti‐invasive properties of hydrophobic statins in MDA‐MB‐231, MDA‐MB‐453 and BT‐549 metastatic triple negative breast cancer cells. Fluvastatin and simvastatin significantly increased cytotoxicity which was reversed with mevalonate. Interestingly, fluvastatin downregulated transferrin receptor (TfR1), with a concomitant depletion of intracellular iron levels in these cells. Statin‐induced effects were mimicked by geranylgeranyl transferase inhibitor (GGTI‐298) but not farnesyl transferase inhibitor (FTI‐277). Further, it was observed that TfR1 downregulation is mediated by increased nitric oxide levels via inducible nitric oxide synthase (iNOS) expression. NOS inhibitors (asymmetric dimethylarginine and 1400W) counteracted and sepiapterin, a precursor of tetrahydrobiopterin, exacerbated statin‐induced depletion of intracellular iron levels. Notably, fluvastatin increased manganese superoxide dismutase (by repressing the transcription factor DNA damage‐binding protein 2), catalase and glutathione which, in turn, diminished H2O2 levels. Fluvastatin‐induced downregulation of TfR1, matrix metalloproteinase‐2, ‐9 and inhibition of invasion were reversed in the presence of aminotriazole, a specific inhibitor of catalase. Finally, we conclude that fluvastatin, by altering iron homeostasis, nitric oxide generation and antioxidant defence mechanisms, induces triple negative breast cancer cell death.

Statin-induced inhibition of breast cancer proliferation and invasion involves attenuation of iron transport: intermediacy of nitric oxide and antioxidant defence mechanisms

Accumulating evidence from in vitro, in vivo, clinical and epidemiological studies shows promising results for the use of statins against many cancers including breast carcinoma. However, the molecular mechanisms responsible for the anti-proliferative and anti-invasive properties of statins still remain elusive. In this study, we investigated the involvement of nitric oxide, iron homeostasis and antioxidant defence mechanisms in mediating the anti-proliferative and anti-invasive properties of hydrophobic statins in MDA-MB-231, MDA-MB-453 and BT-549 metastatic triple negative breast cancer cells. Fluvastatin and simvastatin significantly increased cytotoxicity which was reversed with mevalonate. Interestingly, fluvastatin downregulated transferrin receptor (TfR1), with a concomitant depletion of intracellular iron levels in these cells. Statin-induced effects were mimicked by geranylgeranyl transferase inhibitor (GGTI-298) but not farnesyl transferase inhibitor (FTI-277). Further, it was observed that TfR1 downregulation is mediated by increased nitric oxide levels via inducible nitric oxide synthase (iNOS) expression. NOS inhibitors (asymmetric dimethylarginine and 1400W) counteracted and sepiapterin, a precursor of tetrahydrobiopterin, exacerbated statin-induced depletion of intracellular iron levels. Notably, fluvastatin increased manganese superoxide dismutase (by repressing the transcription factor DNA damage-binding protein 2), catalase and glutathione which, in turn, diminished H2 O2 levels. Fluvastatin-induced downregulation of TfR1, matrix metalloproteinase-2, -9 and inhibition of invasion were reversed in the presence of aminotriazole, a specific inhibitor of catalase. Finally, we conclude that fluvastatin, by altering iron homeostasis, nitric oxide generation and antioxidant defence mechanisms, induces triple negative breast cancer cell death.

A Systems Biology Approach to Deciphering the Etiology of Steatosis Employing Patient-Derived Dermal Fibroblasts and iPS Cells

Non-alcoholic fatty liver disease comprises a broad spectrum of disease states ranging from simple steatosis to non-alcoholic steatohepatitis. As a result of increases in the prevalences of obesity, insulin resistance, and hyperlipidemia, the number of people with hepatic steatosis continues to increase. Differences in susceptibility to steatohepatitis and its progression to cirrhosis have been attributed to a complex interplay of genetic and external factors all addressing the intracellular network. Increase in sugar or refined carbohydrate consumption results in an increase of insulin and insulin resistance that can lead to the accumulation of fat in the liver. Here we demonstrate how a multidisciplinary approach encompassing cellular reprogramming, transcriptomics, proteomics, metabolomics, modeling, network reconstruction, and data management can be employed to unveil the mechanisms underlying the progression of steatosis. Proteomics revealed reduced AKT/mTOR signaling in fibroblasts derived from steatosis patients and further establishes that the insulin-resistant phenotype is present not only in insulin-metabolizing central organs, e.g., the liver, but is also manifested in skin fibroblasts. Transcriptome data enabled the generation of a regulatory network based on the transcription factor SREBF1, linked to a metabolic network of glycerolipid, and fatty acid biosynthesis including the downstream transcriptional targets of SREBF1 which include LIPIN1 (LPIN) and low density lipoprotein receptor. Glutathione metabolism was among the pathways enriched in steatosis patients in comparison to healthy controls. By using a model of the glutathione pathway we predict a significant increase in the flux through glutathione synthesis as both gamma-glutamylcysteine synthetase and glutathione synthetase have an increased flux. We anticipate that a larger cohort of patients and matched controls will confirm our preliminary findings presented here.

Morphology and migration of podocytes are affected by CD151 levels

CD151, a member of the tetraspanin family of membrane proteins, is crucially involved in the formation of the glomerular filtration barrier in humans and mice. However, the role of CD151 in podocytes has not been investigated so far. In the present study, we utilized a conditionally immortalized mouse podocyte cell line to characterize CD151 in podocytes and to examine the consequences of manipulating CD151 expression levels. Mouse podocytes endogenously express CD151 as determined by RT-PCR and Western blotting. GFP-CD151 fusion protein localized to the cell membrane, to cell protrusions and cell-cell contacts, colocalizing with actin, β1-integrin, zonula occludens-1, and CD9. The expression of GFP-CD151 in cultured podocytes resulted in a marked increase in the presence of thin arborized protrusions (TAPs). TAPs are distinct from filopodia by increased length, protein composition, branched morphology, and slower dynamics. Furthermore, the migration rate of pEGFP-CD151-transfected podocytes was reduced in a wound assay. Fluorescence recovery after photo bleaching measurements revealed a half-time of 3 s for GFP-CD151 consistent with a high mobility of CD151 in the membrane and cytosol. CD151 knockdown in podocytes reduced β1-integrin expression and podocyte cell area, indicating diminished adherence and/or spreading. Our results indicate that CD151 importantly modulates podocyte function.

Peroxiredoxins 3 and 4 are overexpressed in prostate cancer tissue and affect the proliferation of prostate cancer cells in vitro

The present study aimed to investigate the proteome profiling of surgically treated prostate cancers. Hereto, 2D-DIGE and mass spectrometry were performed for protein identification, and data validation for peroxiredoxin 3 and 4 (PRDX3 and PRDX4) was accomplished by reverse phase protein arrays (RPPA). The Formal Concept Analysis (FCA) method was applied to assess whether the TMPRSS2-ERG gene fusion could influence the degree of overexpression of PRDX3 and PRDX4 in prostate cancer. Lastly, we performed an in vitro functional characterization of both PRDX3 and PRDX4 using the classical human prostate cancer cell lines DU145 and LNCaP. Reverse phase protein arrays verified that the overexpression of both PRDX3 and PRDX4 in tumor samples is negatively correlated with the presence of the TMPRSS2-ERG gene fusion. Functional characterization of PRDX3 and PRDX4 activity in PCa cell lines suggests a role of these members of the peroxiredoxin family in the pathophysiology of this tumor entity.

Ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) is a potential tumour suppressor in prostate cancer and is frequently silenced by promoter methylation

Background

We have previously reported significant downregulation of ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) in prostate cancer (PCa) compared to the surrounding benign tissue. UCHL1 plays an important role in ubiquitin system and different cellular processes such as cell proliferation and differentiation. We now show that the underlying mechanism of UCHL1 downregulation in PCa is linked to its promoter hypermethylation. Furthermore, we present evidences that UCHL1 expression can affect the behavior of prostate cancer cells in different ways.

Results

Methylation specific PCR analysis results showed a highly methylated promoter region for UCHL1 in 90% (18/20) of tumor tissue compared to 15% (3/20) of normal tissues from PCa patients. Pyrosequencing results confirmed a mean methylation of 41.4% in PCa whereas only 8.6% in normal tissues. To conduct functional analysis of UCHL1 in PCa, UCHL1 is overexpressed in LNCaP cells whose UCHL1 expression is normally suppressed by promoter methylation and found that UCHL1 has the ability to decrease the rate of cell proliferation and suppresses anchorage-independent growth of these cells. In further analysis, we found evidence that exogenous expression of UCHL1 suppress LNCaP cells growth probably via p53-mediated inhibition of Akt/PKB phosphorylation and also via accumulation of p27kip1 a cyclin dependant kinase inhibitor of cell cycle regulating proteins. Notably, we also observed that exogenous expression of UCHL1 induced a senescent phenotype that was detected by using the SA-ß-gal assay and might be due to increased p14ARF, p53, p27kip1 and decreased MDM2.

Conclusion

From these results, we propose that UCHL1 downregulation via promoter hypermethylation plays an important role in various molecular aspects of PCa biology, such as morphological diversification and regulation of proliferation.

Identification of clinically relevant protein targets in prostate cancer with 2D-DIGE coupled mass spectrometry and systems biology network platform

Prostate cancer (PCa) is the most common type of cancer found in men and among the leading causes of cancer death in the western world. In the present study, we compared the individual protein expression patterns from histologically characterized PCa and the surrounding benign tissue obtained by manual micro dissection using highly sensitive two-dimensional differential gel electrophoresis (2D-DIGE) coupled with mass spectrometry. Proteomic data revealed 118 protein spots to be differentially expressed in cancer (n = 24) compared to benign (n = 21) prostate tissue. These spots were analysed by MALDI-TOF-MS/MS and 79 different proteins were identified. Using principal component analysis we could clearly separate tumor and normal tissue and two distinct tumor groups based on the protein expression pattern. By using a systems biology approach, we could map many of these proteins both into major pathways involved in PCa progression as well as into a group of potential diagnostic and/or prognostic markers. Due to complexity of the highly interconnected shortest pathway network, the functional sub networks revealed some of the potential candidate biomarker proteins for further validation. By using a systems biology approach, our study revealed novel proteins and molecular networks with altered expression in PCa. Further functional validation of individual proteins is ongoing and might provide new insights in PCa progression potentially leading to the design of novel diagnostic and therapeutic strategies.

Stereotypical chronic lymphocytic leukemia B-cell receptors recognize survival promoting antigens on stromal cells

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world. Survival of CLL cells depends on their close contact with stromal cells in lymphatic tissues, bone marrow and blood. This microenvironmental regulation of CLL cell survival involves the stromal secretion of chemo- and cytokines as well as the expression of adhesion molecules. Since CLL survival may also be driven by antigenic stimulation through the B-cell antigen receptor (BCR), we explored the hypothesis that these processes may be linked to each other. We tested if stromal cells could serve as an antigen reservoir for CLL cells, thus promoting CLL cell survival by stimulation through the BCR. As a proof of principle, we found that two CLL BCRs with a common stereotyped heavy chain complementarity-determining region 3 (previously characterized as “subset 1”) recognize antigens highly expressed in stromal cells – vimentin and calreticulin. Both antigens are well-documented targets of autoantibodies in autoimmune disorders. We demonstrated that vimentin is displayed on the surface of viable stromal cells and that it is present and bound by the stereotyped CLL BCR in CLL-stroma co-culture supernatant. Blocking the vimentin antigen by recombinant soluble CLL BCR under CLL-stromal cell co-culture conditions reduces stroma-mediated anti-apoptotic effects by 20–45%. We therefore conclude that CLL BCR stimulation by stroma-derived antigens can contribute to the protective effect that the stroma exerts on CLL cells. This finding sheds a new light on the understanding of the pathobiology of this so far mostly incurable disease.

Immunohistochemical expression of caspase-1 and -9, uncleaved caspase-3 and -6, cleaved caspase-3 and -6 as well as Bcl-2 in benign epithelium and cancer of the prostate

Activation of caspases is an essential prerequisite for induction of apoptosis. In many tumors caspases are down-regulated, while anti-apoptotic Bcl-2 is up-regulated. To elucidate their putative role in prostate cancer (PCa) we determined the expression of different caspases and Bcl-2 in benign prostate epithelium (BPE) and PCa. Paraffin-embedded prostate whole mounts were cut (4 μm) and investigated immunohistochemically using monoclonal antibodies against caspase-1 and -9, uncleaved caspase-3 and -6, cleaved caspase-3 and -6, and Bcl-2. In BPE all caspases were localized to the cytoplasm of glandular cells. In PCa we found a statistically significant reduction in cleaved caspase-3 and -6 compared to the levels in BPE. The Bcl-2 protein was detected in the basal compartment of epithelial gland cells, but no immunostaining was noted in PCa. The decreased immunoreactivity of activated caspases probably indicates an alteration in post-translational cleavage that may play an important role during PCa progression.

Altered expression of tumor protein D52 regulates apoptosis and migration of prostate cancer cells

Tumor protein D52 (TPD52) is a protein found to be overexpressed in prostate and breast cancer due to gene amplification. However, its physiological function remains under investigation. In the present study, we investigated the response of the LNCaP human prostate carcinoma cell line to deregulation of TPD52 expression. Proteomic analysis of prostate biopsies showed TPD52 overexpression at the protein level, whereas its transcriptional upregulation was demonstrated by real-time PCR. Transfection of LNCaP cells with a specific small hairpin RNA giving efficient knockdown of TPD52 resulted in significant cell death of the carcinoma LNCaP cells. As demonstrated by activation of caspases (caspase-3 and -9), and by the loss of mitochondrial membrane potential, cell death occurs due to apoptosis. The disruption of the mitochondrial membrane potential indicates that TPD52 acts upstream of the mitochondrial apoptotic reaction. To study the effect of TPD52 expression on cell proliferation, LNCaP cells were either transfected with enhanced green fluorescence protein-TPD52 or a specific small hairpin RNA. Enhanced green fluorescence protein-TPD52 overexpressing cells showed an increased proliferation rate, whereas TPD52-depleted cells showed the reverse effect. Additionally, we demonstrate that exogenous expression of TPD52 promotes cell migration via alphav beta3 integrin in prostate cancer cells through activation of the protein kinase B/Akt signaling pathway. From these results, we conclude that TPD52 plays an important role in various molecular events, particularly in the morphological diversification and dissemination of prostate carcinoma cells, and may be a promising target with respect to developing new therapeutic strategies to treat prostate cancer.