Inhibition of insulin-like growth factor 2 mRNA-binding protein 1 sensitizes colorectal cancer cells to chemotherapeutics.

Although colorectal cancer (CRC) treatment has seen a remarkable improvement in the recent years, many patients will develop metastasis due to the resistance of cancer cells to chemotherapeutics. Targeting mechanisms driving the resistance of CRC cells to treatment would significantly reduce cases of metastasis and death. Induction of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a direct target of the Wnt/ß-catenin signaling pathway, might promote resistance of CRC cells to treatment via activation of anti-apoptotic pathways and induction of the multidrug resistance (MDR1) membrane transporter that pumps drugs out of the cells. We hypothesized that inhibition of IGF2BP1 will sensitize CRC cells to chemotherapeutics. We used CRC cell lines with different status of activation of Wnt signaling to show that inhibition of IGF2BP1 potentiates the anti-growth and anti-proliferative effects of chemotherapeutics on CRC cells with activated Wnt/ß-catenin signaling pathway. We observed that the inhibition of IGF2BP1 significantly increases apoptosis in the same cells. A remarkable reduction in the migratory capability of those cells was noted as well. We found that inhibition of IGF2BP1 is sufficient to decrease the resistance of chemotherapy-resistant cancer cells with activated Wnt/ß-catenin signaling pathway. These findings portray IGF2BP1 as a good candidate for CRC therapy.

Endosomal compartment contributes to the propagation of CD95/Fas-mediated signals in type II cells.

Participation of diverse organelles in the intracellular signalling that follows CD95/Fas receptor ligation encompasses a series of subcellular changes that are mandatory for, or even bolster, the apoptotic cascade. In the present study, we analysed the role of endocytosis in the propagation of cell death signalling after CD95/Fas engagement in type II cells (CEM cells). We show that this receptor-ligand interaction triggers endocytosis independently of any caspase activation. This FasL (Fas ligand)-induced endocytosis also leads to an early and directional 'movement' of endocytic vesicles towards the mitochondrial compartment. In turn, this cross-talk between endosomal and mitochondrial compartments was followed by the loss of the mitochondrial membrane potential and apoptosis execution. This cell remodelling was absent in receptor-independent cell death, such as that induced by the mitochondriotropic drug staurosporine, and in a CEM cell line selected for its multidrug resistance (CEM VBL100). In these cells a reduced FasL (Fas ligand)-induced endocytosis and a reduced organelle cross-talk corresponded to a reduced apoptosis. Altogether, these findings suggest a key role of endocytosis in the propagation and amplification of the CD95/Fas-activated signalling leading to type II cell demise.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induced mitochondrial pathway to apoptosis and caspase activation is potentiated by phospholipid scramblase-3.

Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) initiate pathways of cell death in which caspase activation is mediated either directly (without mitochondrial amplification), or indirectly via the release of apoptogenic factors from mitochondria. Phospholipid scramblases (PLS) are enzymes that play a key role in cellular function by inducing bidirectional movement of membrane lipids. Changes in mitochondrial membrane lipids, cardiolipin, are critical for mediating apoptotic response in many cell-types. PLS3 is a phospholipid scramblase that is localized to mitochondria and is thought to be involved in the regulation of apoptotic signals. Here we report that exogenous-expression of PLS3 enhances apoptotic death induced by TRAIL. This is acheived by potentiating the mitochondrial arm of the death pathway. Thereby, PLS3 expression facilitates changes in mitochondrial membrane lipids that promote the release of apoptogenic factors and consequent full activation and processing of the caspase-9 and effector caspase-3. Moreover, we show that knock-down of endogenous PLS3 suppresses TRAIL-induced changes in cardiolipin. Finally, we demonstrate that TRAIL-induced activation of PKC-delta mediates regulation of the PLS3-induced changes in cardiolipin.

A Peroxidase Peroxiredoxin 1-Specific Redox Regulation of the Novel FOXO3 microRNA Target let-7.

Precision in redox signaling is attained through posttranslational protein modifications such as oxidation of protein thiols. The peroxidase peroxiredoxin 1 (PRDX1) regulates signal transduction through changes in thiol oxidation of its cysteines. We demonstrate here that PRDX1 is a binding partner for the tumor suppressive transcription factor FOXO3 that directly regulates the FOXO3 stress response. Heightened oxidative stress evokes formation of disulfide-bound heterotrimers linking dimeric PRDX1 to monomeric FOXO3. Absence of PRDX1 enhances FOXO3 nuclear localization and transcription that are dependent on the presence of Cys31 or Cys150 within FOXO3. Notably, FOXO3-T32 phosphorylation is constitutively enhanced in these mutants, but nuclear translocation of mutant FOXO3 is restored with PI3K inhibition. Here we show that on H2O2 exposure, transcription of tumor suppressive miRNAs let-7b and let-7c is regulated by FOXO3 or PRDX1 expression levels and that let-7c is a novel target for FOXO3. Conjointly, inhibition of let-7 microRNAs increases let-7-phenotypes in PRDX1-deficient breast cancer cells. Altogether, these data ascertain the existence of an H2O2-sensitive PRDX1-FOXO3 signaling axis that fine tunes FOXO3 activity toward the transcription of gene targets in response to oxidative stress. Antioxid. Redox Signal. 28, 62-77.

Tumor necrosis factor-related apoptosis-inducing ligand alters mitochondrial membrane lipids.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to have selective antitumor activity. TRAIL induces ubiquitous pathways of cell death in which caspase activation is mediated either directly or via the release of apoptogenic factors from mitochondria; however, the precise components of the mitochondrial signaling pathway have not been well defined. Notably, mitochondria constitute an important target in overcoming resistance to TRAIL in many types of tumors. Bid is considered to be fundamental in engaging mitochondria during death receptor-mediated apoptosis, but this action is dependent on mitochondrial lipids. Here, we report that TRAIL signaling induces an alteration in mitochondrial membrane lipids, particularly cardiolipin. This occurs independently of caspase activation and primes mitochondrial membranes to the proapoptotic action of Bid. We unveil a link between TRAIL signaling and alteration of membrane lipid homeostasis that occurs in parallel to apical caspase activation but does not take over the mode of cell death because of the concurrent activation of caspase-8. In particular, TRAIL-induced alteration of mitochondrial lipids follows an imbalance in the cellular homeostasis of phosphatidylcholine, which results in an elevation in diacylglycerol (DAG). Elevated DAG in turn activates the delta isoform of phospholipid-dependent serine/threonine protein kinase C, which then accelerates the cleavage of caspase-8. We also show that preservation of phosphatidylcholine homeostasis by inhibition of lipid-degrading enzymes almost completely impedes the activation of pro-caspase-9 while scarcely changing the activation of caspase-8.

Arsenic Trioxide Induces Apoptosis via Specific Signaling Pathways in HT-29 Colon Cancer Cells.

BACKGROUND: Arsenic trioxide (ATO) is highly effective in the treatment of patients with acute promyelocytic leukemia (APL). It is a chemotherapeutic agent that has been shown to induce apoptosis in several tumor cell lines. However, research into its effects on colon carcinoma cells is still very limited. We previously reported that ATO is cytotoxic and causes DNA damage in HT-29 human colorectal adenocarcinoma cells. In the present study, we further evaluated its effect on oxidative stress (OS), and examined its apoptotic mechanisms of action on HT-29 cells. METHODS: OS was assessed by spectrophotometric measurements of MDA levels while cell cycle analysis was evaluated by flow cytometry to determine whether ATO induces cell cycle arrest. Its effect on early apoptosis was also evaluated by flow cytometry using Annexin V-FITC/PI staining. Fluorescence microscopy was used to detect the morphological changes, and Western blotting was carried out to determine the expression of apoptosis-related proteins. RESULTS: The lipid peroxidation assay revealed a dose-dependent increase in MDA production. DAPI staining showed morphological changes in the cell's nucleus due to apoptosis. Cell cycle analysis and Annexin V-FITC assay also demonstrated a dose-dependent effect of ATO in the accumulation of cells at the sub G1 phase, and the percentages of Annexin V-positive cells, respectively. Western blot data showed that ATO upregulated the expression of caspase 3, Bax, and cytochrome C, and down-regulated the expression of Bcl-2. CONCLUSION: Taken together, our findings indicate that ATO induces OS and cytotoxicity in HT-29 cells through the mitochondria mediated intrinsic pathway of apoptosis.

Evaluation of Arsenic Trioxide Potential for Lung Cancer Treatment: Assessment of Apoptotic Mechanisms and Oxidative Damage.

BACKGROUND: Lung cancer is one of the most lethal and common cancers in the world, causing up to 3 million deaths annually. The chemotherapeutic drugs that have been used in treating lung cancer include cisplatin-pemetrexed, cisplastin-gencitabinoe, carboplatin-paclitaxel and crizotinib. Arsenic trioxide (ATO) has been used in the treatment of acute promyelocytic leukemia. However, its effects on lung cancer are not known. We hypothesize that ATO may also have a bioactivity against lung cancer, and its mechanisms of action may involve apoptosis, DNA damage and changes in stress-related proteins in lung cancer cells. METHODS: To test the above stated hypothesis, lung carcinoma (A549) cells were used as the test model. The effects of ATO were examined by performing 6-diamidine-2 phenylindole (DAPI) nuclear staining for morphological characterization of apoptosis, flow cytometry analysis for early apoptosis, and western blot analysis for stress-related proteins (Hsp70 and cfos) and apoptotic protein expressions. Also, the single cell gel electrophoresis (Comet) assay was used to evaluate the genotoxic effect. RESULTS: ATO-induced apoptosis was evidenced by chromatin condensation and formation of apoptotic bodies as revealed by DAPI nuclear staining. Cell shrinkage and membrane blebbing were observed at 4 and 6 µg/ml of ATO. Data from the western blot analysis revealed a significant dose-dependent increase (p < 0.05) in the Hsp 70, caspase 3 and p53 protein expression, and a significant (p < 0.05) decrease in the cfos, and bcl-2 protein expression at 4 and 6 µg/ml of ATO. There was a slight decrease in cytochrome c protein expression at 4 and 6 µg/ ml of ATO. Comet assay data revealed significant dose-dependent increases in the percentages of DNA damage, Comet tail lengths, and Comet tail moment. CONCLUSION: Taken together our results indicate that ATO is cytotoxic to lung cancer cells and its bioactivity is associated with oxidative damage, changes in cellular morphology, and apoptosis.

Meta-analysis of transcriptome data identifies a novel 5-gene pancreatic adenocarcinoma classifier.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is largely incurable due to late diagnosis. Superior early detection biomarkers are critical to improving PDAC survival and risk stratification. EXPERIMENTAL DESIGN: Optimized meta-analysis of PDAC transcriptome datasets identified and validated key PDAC biomarkers. PDAC-specific expression of a 5-gene biomarker panel was measured by qRT-PCR in microdissected patient-derived FFPE tissues. Cell-based assays assessed impact of two of these biomarkers, TMPRSS4 and ECT2, on PDAC cells. RESULTS: A 5-gene PDAC classifier (TMPRSS4, AHNAK2, POSTN, ECT2, SERPINB5) achieved on average 95% sensitivity and 89% specificity in discriminating PDAC from non-tumor samples in four training sets and similar performance (sensitivity = 94%, specificity = 89.6%) in five independent validation datasets. This classifier accurately discriminated PDAC from chronic pancreatitis (AUC = 0.83), other cancers (AUC = 0.89), and non-tumor from PDAC precursors (AUC = 0.92) in three independent datasets. Importantly, the classifier distinguished PanIN from healthy pancreas in the PDX1-Cre;LSL-KrasG12D PDAC mouse model. Discriminatory expression of the PDAC classifier genes was confirmed in microdissected FFPE samples of PDAC and matched surrounding non-tumor pancreas or pancreatitis. Notably, knock-down of TMPRSS4 and ECT2 reduced PDAC soft agar growth and cell viability and TMPRSS4 knockdown also blocked PDAC migration and invasion. CONCLUSIONS: This study identified and validated a highly accurate 5-gene PDAC classifier for discriminating PDAC and early precursor lesions from non-malignant tissue that may facilitate early diagnosis and risk stratification upon validation in prospective clinical trials. Cell-based experiments of two overexpressed proteins encoded by the panel, TMPRSS4 and ECT2, suggest a causal link to PDAC development and progression, confirming them as potential therapeutic targets.

Multiple signaling is involved in endostatin-mediated apoptosis in ECV 304 endothelial cells.

Apoptosis of vascular endothelial cells is associated with the regression of angiogenesis. Endostatin is a potential anti-angiogenic drug, but the effects of endostatin on apoptotic machinery in endothelial cells largely remain unclear. In the present study, human endostatin was expressed in E. Coli to induce apoptosis in endothelial cells. It was found that the expressed human endostatin specifically affected the viability of the ECV 304 in a dose-dependent manner. Endostatin induced apoptosis in these cells in a caspase-dependent manner, and endostatin-mediated apoptosis is associated with several apoptotic signaling pathways including overloading of intracellular magnesium and calcium, as well as regulation of p53 and Bcl 2 expression.

Effect of light irradiation and sex hormones on jurkat T cells: 17beta-estradiol but not testosterone enhances UVA-induced cytotoxicity in Jurkat lymphocytes.

In Eastern cultures, such as India, it is traditionally recommended that women but not men cover their heads while working in the scorching sun. The purpose of this pilot study was to determine whether there was any scientific basis for this cultural tradition. We examined the differential cytotoxic effects of ultraviolet A light (UVA) on an established T cell line treated with female and male sex hormones. CD4+ Jurkat T cells were plated in 96 well plates at 2 x 106 cells/ml and treated with 17beta-estradiol (EST) or testosterone (TE). These cells were irradiated by UVA light with an irradiance of 170 J/cm2 for 15min at a distance of 6 cm from the surface of the 96-well plate. Controls included cells not treated with hormones or UVA. The effects of EST and TE were investigated between 1 and 20 ng/mL. Cytotoxicity by fluorescein-diacetate staining and COMET assay generating single strand DNA cleavage, tail length and tail moment measurements were examined. The effect of estrogen (5ng/mL) on apoptosis and its mediators was further studied using DNA laddering and western blotting for bcl-2 and p53. We found that EST alone, without UVA, enhanced Jurkat T cell survival. However, EST exhibited a dose-related cytotoxicity in the presence of UVA; up to 28% at 20 ng/ml. TE did not alter UVA-induced cytotoxicity. Since TE did not alter cell viability in the presence of UVA further damaging studies were not performed. COMET assay demonstrated the harmful effects of EST in the presence of UVA while EST without UVA. had no significant effect on the nuclear damage. Apoptosis was not present as indicated by the absence of DNA laddering on agarose gel electrophoresis at 5ng/ml EST or TE +/- UVA. Western blot showed that estrogen down regulated bcl-2 independently of UVA radiation while p53 was down regulated in the presence of UVA treatment. EST and TE have differential effects on UVA-induced cytotoxicity in Jurkat T-lymphocyte which suggested that women may be more susceptible to the harmful effects of solar irradiation than men.

Secondary Data Analytics of Aquaporin Expression Levels in Glioblastoma Stem-Like Cells.

Glioblastoma is the most common brain tumor in adults in which recurrence has been attributed to the presence of cancer stem cells in a hypoxic microenvironment. On the basis of tumor formation in vivo and growth type in vitro, two published microarray gene expression profiling studies grouped nine glioblastoma stem-like (GS) cell lines into one of two groups: full (GSf) or restricted (GSr) stem-like phenotypes. Aquaporin-1 (AQP1) and aquaporin-4 (AQP4) are water transport proteins that are highly expressed in primary glial-derived tumors. However, the expression levels of AQP1 and AQP4 have not been previously described in a panel of 92 glioma samples. Therefore, we designed secondary data analytics methods to determine the expression levels of AQP1 and AQP4 in GS cell lines and glioblastoma neurospheres. Our investigation also included a total of 2,566 expression levels from 28 Affymetrix microarray probe sets encoding 13 human aquaporins (AQP0-AQP12); CXCR4 (the receptor for stromal cell derived factor-1 [SDF-1], a potential glioma stem cell therapeutic target]); and PROM1 (gene encoding CD133, the widely used glioma stem cell marker). Interactive visual representation designs for integrating phenotypic features and expression levels revealed that inverse expression levels of AQP1 and AQP4 correlate with distinct phenotypes in a set of cell lines grouped into full and restricted stem-like phenotypes. Discriminant function analysis further revealed that AQP1 and AQP4 expression are better predictors for tumor formation and growth types in glioblastoma stem-like cells than are CXCR4 and PROM1. Future investigations are needed to characterize the molecular mechanisms for inverse expression levels of AQP1 and AQP4 in the glioblastoma stem-like neurospheres.

Coumestrol, bisphenol-A, DDT, and TCDD modulation of interleukin-2 expression in activated CD+4 Jurkat T cells.

Endogenous estrogens are known to modulate several components of immune response, including interleukin-2 (IL-2) production. IL-2 is a cytokine that plays an important role in adaptive immune responses. These responses may be modulated by xenoestrogens such as coumestrol, bisphenol A (BPA), DDT, and TCDD. In this research, we examined the effects and potential mechanisms of action of these estrogenic compounds on IL-2 production in activated CD4+ Jurkat T cells. IL-2 production was analyzed by ELISA and Western Blot. At the transcriptional level, protein expression was examined by RT-PCR. Coumestrol, DDT and TCDD (but not BPA) significantly suppressed IL-2 production in activated CD4+ Jurkat T cells, at the transcriptional and translational levels. The transcriptional suppression of IL-2 was associated with decreased protein levels of NF-kappabeta, an important IL-2 positive transcription factor, without affecting the expression of Ikappa-Balpha protein expression, an important inhibitor of NF-kappabeta nuclear translocation. Although the direct mechanisms of xenoestrogens modulation of the immune system remain to be elucidated, coumestrol-, DDT- and TCDD-induced suppression of IL-2 may have ramifications for our understanding of the impact of xenoestrogens on health and disease.

The Renin-Angiotensin-aldosterone system in vascular inflammation and remodeling.

The RAAS through its physiological effectors plays a key role in promoting and maintaining inflammation. Inflammation is an important mechanism in the development and progression of CVD such as hypertension and atherosclerosis. In addition to its main role in regulating blood pressure and its role in hypertension, RAAS has proinflammatory and profibrotic effects at cellular and molecular levels. Blocking RAAS provides beneficial effects for the treatment of cardiovascular and renal diseases. Evidence shows that inhibition of RAAS positively influences vascular remodeling thus improving CVD outcomes. The beneficial vascular effects of RAAS inhibition are likely due to decreasing vascular inflammation, oxidative stress, endothelial dysfunction, and positive effects on regeneration of endothelial progenitor cells. Inflammatory factors such as ICAM-1, VCAM-1, TNFα, IL-6, and CRP have key roles in mediating vascular inflammation and blocking RAAS negatively modulates the levels of these inflammatory molecules. Some of these inflammatory markers are clinically associated with CVD events. More studies are required to establish long-term effects of RAAS inhibition on vascular inflammation, vascular cells regeneration, and CVD clinical outcomes. This review presents important information on RAAS's role on vascular inflammation, vascular cells responses to RAAS, and inhibition of RAAS signaling in the context of vascular inflammation, vascular remodeling, and vascular inflammation-associated CVD. Nevertheless, the review also equates the need to rethink and rediscover new RAAS inhibitors.

Di-ethylhexylphthalate (DEHP) modulates cell invasion, migration and anchorage independent growth through targeting S100P in LN-229 glioblastoma cells.

Glioblastoma multiforme (GBM) is the most aggressive brain cancer with a median survival of 1-2 years. The treatment of GBM includes surgical resection, radiation and chemotherapy, which minimally extends survival. This poor prognosis necessitates the identification of novel molecular targets associated with glioblastoma. S100P is associated with drug resistance, metastasis, and poor clinical outcomes in many malignancies. The functional role of S100P in glioblastoma has not been fully investigated. In this study, we examined the role of S100P mediating the effects of the environmental contaminant, DEHP, in glioblastoma cells (LN-229) by assessing cell proliferation, apoptosis, anchorage independent growth, cell migration and invasion following DEHP exposure. Silencing S100P and DEHP treatment inhibited LN-229 glioblastoma cell proliferation and induced apoptosis. Anchorage independent growth study revealed significantly decreased colony formation in shS100P cells. We also observed reduced cell migration in cells treated with DEHP following S100P knockdown. Similar results were observed in spheroid formation and expansion. This study is the first to demonstrate the effects of DEHP on glioblastoma cells, and implicates S100P as a potential therapeutic target that may be useful as a drug response biomarker.

Enhancement of arsenic trioxide-mediated changes in human induced pluripotent stem cells (IPS).

Induced pluripotent stem cells (IPS) are an artificially derived type of pluripotent stem cell, showing many of the same characteristics as natural pluripotent stem cells. IPS are a hopeful therapeutic model; however there is a critical need to determine their response to environmental toxins. Effects of arsenic on cells have been studied extensively; however, its effect on IPS is yet to be elucidated. Arsenic trioxide (ATO) has been shown to inhibit cell proliferation, induce apoptosis and genotoxicity in many cells. Based on ATOs action in other cells, we hypothesize that it will induce alterations in morphology, inhibit cell viability and induce a genotoxic effect on IPS. Cells were treated for 24 hours with ATO (0-9 µg/mL). Cell morphology, viability and DNA damage were documented. Results indicated sufficient changes in morphology of cell colonies mainly in cell ability to maintain grouping and ability to remain adherent. Cell viability decreased in a dose dependent manner. There were significant increases in tail length and moment as well as destruction of intact DNA as concentration increased. Exposure to ATO resulted in a reproducible dose dependent sequence of events marked by changes in morphology, decrease of cell viability, and induction of genotoxicity in IPS.

Aberrantly Expressed Genes in HaCaT Keratinocytes Chronically Exposed to Arsenic Trioxide.

Inorganic arsenic is a known environmental toxicant and carcinogen of global public health concern. Arsenic is genotoxic and cytotoxic to human keratinocytes. However, the biological pathways perturbed in keratinocytes by low chronic dose inorganic arsenic are not completely understood. The objective of the investigation was to discover the mechanism of arsenic carcinogenicity in human epidermal keratinocytes. We hypothesize that a combined strategy of DNA microarray, qRT-PCR and gene function annotation will identify aberrantly expressed genes in HaCaT keratinocyte cell line after chronic treatment with arsenic trioxide. Microarray data analysis identified 14 up-regulated genes and 21 down-regulated genes in response to arsenic trioxide. The expression of 4 up-regulated genes and 1 down-regulated gene were confirmed by qRT-PCR. The up-regulated genes were AKR1C3 (Aldo-Keto Reductase family 1, member C3), IGFL1 (Insulin Growth Factor-Like family member 1), IL1R2 (Interleukin 1 Receptor, type 2), and TNFSF18 (Tumor Necrosis Factor [ligand] SuperFamily, member 18) and down-regulated gene was RGS2 (Regulator of G-protein Signaling 2). The observed over expression of TNFSF18 (167 fold) coupled with moderate expression of IGFL1 (3.1 fold), IL1R2 (5.9 fold) and AKR1C3 (9.2 fold) with a decreased RGS2 (2.0 fold) suggests that chronic arsenic exposure could produce sustained levels of TNF with modulation by an IL-1 analogue resulting in chronic immunologic insult. A concomitant decrease in growth inhibiting gene (RGS2) and increase in AKR1C3 may contribute to chronic inflammation leading to metaplasia, which may eventually lead to carcinogenicity in the skin keratinocytes. Also, increased expression of IGFL1 may trigger cancer development and progression in HaCaT keratinocytes.

Erratum for "Aberrantly Expressed Genes in HaCaT Keratinocytes Chronically Exposed to Arsenic Trioxide".

[This corrects the article on p. 7 in vol. 6, PMID: 21461292.].

Retinoids and citral modulated cell viability, metabolic stability, cell cycle progression and distribution in the a549 lung carcinoma cell line - biomed 2010.

Lung cancer is the second leading deadly cancer in United States. In 2007, the United States reported 213,380 new lung cancer diagnoses and 160,390 deaths caused by lung cancer. Retinoic acid and retinyl esters are the oxidized and storage forms of vitamin A in the body. At low levels, they maintain many functions as hormones affecting vision, bone growth, reproduction, cellular division, and differentiation. Recent publications have found retinoid receptors to be effective therapeutic targets in some cancer cell lines and that retinoids were functional cell modulators of the RAR/RXR nuclear hormone receptors that may impact the development of lung cancer. We hypothesize that retinoic acid and retinyl esters will negatively impact the A549 lung carcinoma cell line model in vitro and that exposure to higher concentrations of retinoids will induce impairments indicative of metabolic implications seen in chronic conditions such as cancer. Citrals are specific inhibitors of retinoid metabolism and are employed to ascertain the specificity of retinoid impacts on the cell model. The aim of this study was to expose the A549 cell line model to various concentrations of retinoic acid, and Citrals (0-160 g/ml). Growth patterns of exposed cells were screened during time intervals ranging from 24-72 hours. The effects were measured through phase microscopy, cell proliferation MTT assay, FACS analysis for cell cycle parameters and western blot analyses for cyclins. Data generated from phase contrast microscopy and MTT assays showed an increased physical destruction, metabolic impairment and a decrease in the viability of A549 cell line model after 72 hours of exposure to retinoic acids and. Observations on the effects exhibited with Citrals (cis and trans vs. diethyl acetal) suggests the reversal of retinoid toxicity and a decrease in cell metabolic as well as physical destructions and positive cell proliferation. Results from FACS analysis showed modulation in the cell cycle distribution/progression upon exposure to retinoids and that Citrals did reverse these effects in the cell line model. Western blot analysis confirmed the findings obtained from testing parameters. We conclude that modulation of metabolic integrity, cell cycle distribution and cell survival through retinoids/citrals in the lung carcinoma model is promising and warrants further therapeutic investigation.

Significance of differential metal loads in normal versus cancerous cadaver tissues - biomed 2010.

The bodys elemental/ metal loads are known to exert essential influence in maintaining normal and abnormal metabolism leading to eventual pathology of some forms of cancer phenotypes. Accumulation of potentially toxic or nonessential trace metals has been observed but not highly noted as an active factor in toxicogenesis and in the development of many diseases including cancers. The compositional balance and distribution of trace metals in various body tissues are essential key players in homeostasis in life. To this end the etiology of diseases including cancer has been linked with the accumulation of potentially toxic or nonessential trace metals. However, scarce literature / experimental evidence exist as a scientific proof that metal concentrations play important role in the etiology and development of cancer phenotypes. The aim of this study was to investigate the differential relationship of metal concentrations and profiles in cancer and normal tissues from cadavers of humans. The originated hypothesis was that elemental / metal concentrations and profiles seen in post mortem will show significant differences between normal and cancer-derived tissues as well as between various tissue types in humans. This study also establishes critical elemental /metal profiles that may be relevant in providing correlations with the development of three major cancers. Normal human and tumor tissues of cadaverous lung, breast and liver tissues used in this study were obtained from US Biomax Company. Tissue samples were prepared using standardized digestion procedures necessary for use with the Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). This equipment was utilized to determine the concentrations and profiles of 21 elements including Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Tl, V, and Zn. Twelve major elements of Al, Ba, Ca, Cr, Cu, Fe, Mg, Na, Pb, Se, Sr, and Zn were found to be significantly different in term of their concentrations / profiles in normal and tumor tissues of human lung, breast and liver. These critical elements appeared to be respectively five to ten times more abundant in human lung and breast tumor than in their respective normal tissues. In contrast Ba, Cr, Cu, Fe, Zn, concentrations were shown to be lower in liver tumors than in normal liver tissues, and that Ca and Na appeared to be higher in human liver tumors than in normal liver tissues. Data analysis showed significant variations in elemental concentrations and profiles consistent with the hypothesis. It is concluded that metal / elemental homeostasis is essential for normal tissue function and that elemental variations and distributions are tissue specific as well as carcinoma specific. These results are promising and warrant further studies to confirm / exploit the possibility of manipulating elemental distribution and content as means for diagnosing / utility as therapeutic modalities in chronic human disease as well as cancer management.

Estrogenic activity of coumestrol, DDT, and TCDD in human cervical cancer cells.

Endogenous estrogens have dramatic and differential effects on classical endocrine organ and proliferation. Xenoestrogens are environmental estrogens that have endocrine impact, acting as both estrogen agonists and antagonists, but whose effects are not well characterized. In this investigation we sought to delineate effects of xenoestrogens. Using human cervical cancer cells (HeLa cells) as a model, the effects of representative xenoestrogens (Coumestrol-a phytoestrogen, tetrachlorodioxin (TCDD)-a herbicide and DDT-a pesticide) on proliferation, cell cycle, and apoptosis were examined. These xenoestrogens and estrogen inhibited the proliferation of Hela cells in a dose dependent manner from 20 to 120 nM suggesting, that 17-beta-estrtadiol and xenoestrogens induced cytotoxic effects. Coumestrol produced accumulation of HeLa cells in G2/M phase, and subsequently induced apoptosis. Similar effects were observed in estrogen treated cells. These changes were associated with suppressed bcl-2 protein and augmented Cyclins A and D proteins. DDT and TCDD exposure did not induce apoptosis. These preliminary data taken together, suggest that xenoestrogens have direct, compound-specific effects on HeLa cells. This study further enhances our understanding of environmental modulation of cervical cancer.