Piperlongumine targets NF-κB and its downstream signaling pathways to suppress tumor growth and metastatic potential in experimental colon cancer.

NF-κB is the principle transcription factor and plays the central role in orchestrating chronic inflammation by regulating levels of cytokines, chemokines and growth factors. Piperlongumine (PL), a major alkaloid in the fruit of Piper longum Linn. has gained worldwide attention for its anticancer properties, however, its mechanism of action in the chemoprevention of colon cancer has not been investigated yet. Therefore, the present study was designed to elucidate the underlying molecular mechanism of PL in preventing DMH/DSS induced experimental colon cancer in mice. In the current study well established DMH/DSS induced experimental colon cancer mouse model was used to demonstrate the chemopreventive potential of PL. The expression of NF-κB and its downstream target proteins was evaluated mainly through western blotting. In addition, CAM assay, immunohistochemical staining and gelatin zymography was used to show anti-angiogenic and anti-invasive potential of PL. Additionally, important tumor biomarkers such as TSA, LASA, LDH and IL-6 levels were also estimated. The results of current study showed that PL was capable to inhibit NF-κB activation as well as its nuclear translocation. PL administration to DMH/DSS treated mice also inhibited the NF-κB downstream signaling cascades such as including COX-2 pathway, JAK/STAT pathway, ß-catenin, Notch signaling pathway, angiogenesis and epithelial to mesenchymal transition pathway. The findings of the present study have claimed PL as promising chemopreventive agent for colon cancer with pleiotropic action. The current study emphasizes that regular consumption of PL can be an effective approach in the prevention of colon cancer in humans.

Elucidation of underlying molecular mechanism of 5-Fluorouracil chemoresistance and its restoration using fish oil in experimental colon carcinoma.

Latest strategies for cancer treatment primarily focus on the use of chemosensitizers to enhance therapeutic outcome. N-3 PUFAs have emerged as the strongest candidate for the prevention of colorectal cancer (CRC). Our previous studies have demonstrated that fish oil (FO) rich in n-3 PUFAs not only increased therapeutic potential of 5-Fluorouracil(5-FU) in colon cancer but also ameliorated its toxicity. Henceforth, the present study is designed to elucidate mechanistic insights of FO as a chemosensitizer to circumvent drug resistance in experimental colon carcinoma. The colon cancer was induced by 1,2-dimethylhydrazine(DMH)/dextran sulfate sodium(DSS) in male Balb/c mice and these animals were treated with 5-FU(12.5 mg/kg b.w.), FO(0.2 ml), or 5-FU + FO(12.5 mg/kg b.w + 0.2 ml) orally for 14 days. The molecular mechanism of overcoming 5-FU resistance using FO in colon cancer was delineated by estimating expression of cancer stem cell markers using flowcytometric method and drug transporters by immunohistochemistry and immunoblotting. Additionally, distribution profile of 5-FU and its cytotoxic metabolite, 5-FdUMP at target(colon), and non-target sites (serum, kidney, liver, spleen) was assessed using high-performance liquid chromatography(HPLC) method. The observations revealed that expression of CSCs markers was remarkably reduced after using fish oil along with 5-FU in carcinogen-treated animals. Interestingly, the use of FO alongwith 5-FU also significantly declined the expression of drug transporters (ABCB1,ABCC5) and consequently resulted in an increased cellular uptake of 5-FU and its metabolite, 5-FdUMP at target site (colon). It could be possibly associated with change in permeability of cell membrane owing to the alteration in membrane fluidity. The present study revealed the mechanistic insights of FO as a MDR revertant which successfully restored 5-FU-mediated chemoresistance in experimental colon carcinoma.

Electrochemical biosensor for miRNA-21 based on gold-platinum bimetallic nanoparticles coated 3-aminopropyltriethoxy silane.

We report an electrochemical biosensor based on gold platinum bimetallic nanoparticles (AuPtBNPs)/3-aminopropyltriethoxy silane (APTS) nanocomposite coated fluorine-doped tin oxide (FTO) as a biosensing platform for hybridization-based detection of miRNA-21. Field Emission-Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and electrochemical measurements were carried out to ensure the successful construction of the biosensor. The amount of cDNA immobilized on electrode surface and hybridization time required for the miRNA-21 sensing were optimized. The biosensing platform showed detection limit of 0.63 fM with wide linear range i.e. 1 fM-100 nM for miRNA-21 detection. The biosensing strategy demonstrates a good recovery yield from 90.18% to 94.6% in serum samples. It offers good selectivity for its complementary miRNA compared to the non-complementary miRNAs. Other analytical features of the biosensor such as stability, reusability and reproducibility were also tested, providing appropriate results.

A voltammetric hybridization assay for microRNA-21 using carboxylated graphene oxide decorated with gold-platinum bimetallic nanoparticles.

An electrochemical hybridization assay is described for the determination of microRNA-21. Fluorine tin oxide (FTO) sheets were coated with carboxylated graphene oxide followed by deposition of gold-platinum bimetallic nanoparticles by using chronoamperometry at a potential of -0.2 V for 350 s. The capture probe was immobilized on the surface of the modified FTO sheets by biotin-avidin interaction. On exposure to microRNA-21, hybridization occurs, and that can be detected at a relatively low working potential of 0.25 V by using ferri/ferro-cyanide as an electrochemical probe. The various modifications of the FTO sheets were characterized by means of FE-SEM, FT-IR, contact angle studies and electrochemical techniques. The effects of pH value, EDC-NHS activation time, concentration of capture probe and incubation time were optimized. The sensor has a wide linear response that extends from 1 fM to 1 µM of microRNA-21, and the detection limit is 1 fM. The sensor is stable for about 15 days (by retaining 90% of its initial activity) and can be reused for about 3 times (85% of initial activity) after regeneration with 50 mM NaOH solution. The sensor was applied to the analysis of spiked human serum and gave recoveries between 90 and 111%. Graphical abstract Carboxylated graphene oxide (CGO) coated on a fluorine tin oxide (FTO) electrode was decorated with Au-Pt bimetallic nanoparticles (Au-PtBNPs). The Au-PtBNPs/CGO/FTO electrode surface was used for immobilizing streptavidin and biotinylated capture probe which can electrochemically detect microRNA-21 based on its sequence complementarity.

Apoptosis mediated chemosensitization of tumor cells to 5-fluorouracil on supplementation of fish oil in experimental colon carcinoma.

5-Fluorouracil has been considered as a cornerstone therapy for colorectal cancer; however, it suffers from low therapeutic response rate and severe side effects. Therefore, there is an urgent need to increase the clinical efficacy of 5-fluorouracil. Recently, fish oil rich in n-3 polyunsaturated fatty acids has been reported to chemosensitize tumor cells to anti-cancer drugs. This study is designed to understand the underlying mechanisms of synergistic effect of fish oil and 5-fluorouracil by evaluation of tumor cell-associated markers such as apoptosis and DNA damage. The colon cancer was developed by administration of N,N-dimethylhydrazine dihydrochloride and dextran sulfate sodium salt. Further these animals were treated with 5-fluorouracil, fish oil, or a combination of both. In carcinogen-treated animals, a decrease in DNA damage and apoptotic index was observed. There was also a decrease in the expression of Fas, FasL, caspase 8, and Bax, and an increase in Bcl-2. In contrast, administration of 5-fluorouracil and fish oil as an adjuvant increased both DNA damage and apoptotic index by activation of both extrinsic and intrinsic apoptotic pathways as compared to the other groups. The increased pro-apoptotic effect by synergism of 5-fluorouracil and fish oil may be attributed to the incorporation of n-3 polyunsaturated fatty acids in membrane, which alters membrane fluidity in cancer cells. In conclusion, this study highlights that the induction of apoptotic pathway by fish oil may increase the susceptibility of tumors to chemotherapeutic regimens.

Transglutaminase-2: evolution from pedestrian protein to a promising therapeutic target.

The ability of cancer cells to metastasize represents the most devastating feature of cancer. Currently, there are no specific biomarkers or therapeutic targets that can be used to predict the risk or to treat metastatic cancer. Many recent reports have demonstrated elevated expression of transglutaminase 2 (TG2) in multiple drug-resistant and metastatic cancer cells. TG2 is a multifunctional protein mostly known for catalyzing Ca2+-dependent -acyl transferase reaction to form protein crosslinks. Besides this transamidase activity, many Ca2+-independent and non-enzymatic activities of TG2 have been identified. Both, the enzymatic and non-enzymatic activities of TG2 have been implicated in diverse pathophysiological processes such as wound healing, cell growth, cell survival, extracellular matrix modification, apoptosis, and autophagy. Tumors have been frequently referred to as 'wounds that never heal'. Based on the observation that TG2 plays an important role in wound healing and inflammation is known to facilitate cancer growth and progression, we discuss the evidence that TG2 can reprogram inflammatory signaling networks that play fundamental roles in cancer progression. TG2-regulated signaling bestows on cancer cells the ability to proliferate, to resist cell death, to invade, to reprogram glucose metabolism and to metastasize, the attributes that are considered important hallmarks of cancer. Therefore, inhibiting TG2 may offer a novel therapeutic approach for managing and treatment of metastatic cancer. Strategies to inhibit TG2-regulated pathways will also be discussed.

Proteomic analysis of differentially expressed proteins in vitreous humor of patients with retinoblastoma using iTRAQ-coupled ESI-MS/MS approach.

There is close proximity of vitreous humor with the tumor bulk in eyes with retinoblastoma. This renders vitreous humor a promising source to evaluate disease-specific protein targets in retinoblastoma. We studied the differential proteome of vitreous fluid in retinoblastoma tumors (n = 4) as compared to controls (n = 4). The vitreous humor was depleted off the high abundant fraction using MARS-6 affinity column. Subsequently, the tryptic peptides were derivatised with iTRAQ labels. The labelled peptides were pooled and subjected to fractionation using bRPLC. This was followed by protein identification and quantification using electrospray ionisation mass spectrometry (ESI-MS/MS) approach. The identified proteins were subjected to bioinformatics analysis utilizing PANTHER 7.0 and IPA software. Four hundred and thirty-one non-redundant (362 upregulated and 69 downregulated) proteins (≥2 unique peptides, ± 1.5 folds, p < 0.05) were identified. The majority of the proteins were cytoplasmic (40 %), majorly involved in catalytic (32.7 %) and binding activities (26.3 %). Highly deregulated proteins included MMP2, TNC, CD44, SUZ12 and CRABP1. The protein expression of GFAP, CRABP1, MMP2 and TNC was validated by western blotting. Pathway and network analyses revealed p38MAPK and Akt signalling to be the most significantly regulated pathways in retinoblastoma. This is the first report of differential vitreous proteome of retinoblastoma and highlights novel protein targets, such as MMP2, TNC and CRABP1. Further investigations into unravelling the biological role of the proteins and their prospects of being utilised as potential candidates in therapeutics are warranted.

Apoptosis-Mediated Chemoprevention by Different Ratios of Fish Oil in Experimental Colon Carcinogenesis.

Apoptosis plays an important role in prevention of colon cancer. In the present study, different ratios of fish oil and corn oil increased Fas expression in both phases and a decrease in FasL expression only in post initiation phase. Treatment with fish oil activated the intrinsic apoptotic pathway by increasing Bax expression and Cyt c release and decreasing Bcl-2 levels in both phases. This suggests that intrinsic pathway is upregulated by fish oil; however, Fas-FasL activity may be involved in inhibition of reversal of immune surveillance in tumor cells.

Celecoxib and fish oil: a combination strategy for decreased inflammatory mediators in early stages of experimental mammary cancer.

Chronic inflammation has been directly linked to cancer progression. Therefore, current study was designed to understand the mechanism of action of chemo-preventive effect of celecoxib and fish oil on inflammatory mediators in experimental mammary carcinoma. Female Wistar rats were distributed into control and DMBA treated groups and further subdivided based on pretreatment with celecoxib and/or fish oil. Inflammation was measured by assessing expression of NF-κB, COX-2 and cytokines. The results indicated an elevation in expression of NF-κB, COX-2 and cytokines' levels (IFN-γ, IL-4 and IL-10) in DMBA group as compared to controls. On pretreatment with celecoxib and/or fish oil in DMBA treated animals, a significant reduction in expression of NF-κB, COX-2 and cytokines' levels was observed. The decrease was more pronounced with combinatorial regimen than either celecoxib or fish oil alone. To conclude, a combinatorial strategy of celecoxib and fish oil may generate an immune response against the tumor cell by altering cytokine repertoire and decrease the tendency of tumor cells to escape immune surveillance.

Documentation of Ultrastructural Changes in Nucleus and Microvilli by Fish Oil in Experimental Colon Carcinogenesis.

Fish oil (FO) exerts a chemopreventive effect by regulating apoptosis in colon carcinogenesis. The present study reports the ultrastructural changes in various organelles on supplementation of FO in experimental colon carcinogenesis. The carcinogen treatment led to abnormal nuclear shape and alteration in microvilli number indicating cancer establishment. On the other hand, different ratios of FO and corn oil increased chromatin condensation along with an extensive loss of microvilli in a dose- and time-dependent manner which depicts an increase in apoptosis. The associated ultrastuctural alterations support the facilitation of apoptosis by FO as a mechanism for its beneficial effect in colon carcinogenesis.

Transglutaminase 2 reprogramming of glucose metabolism in mammary epithelial cells via activation of inflammatory signaling pathways.

Aberrant glucose metabolism characterized by high levels of glycolysis, even in the presence of oxygen, is an important hallmark of cancer. This metabolic reprogramming referred to as the Warburg effect is essential to the survival of tumor cells and provides them with substrates required for biomass generation. Molecular mechanisms responsible for this shift in glucose metabolism remain elusive. As described herein, we found that aberrant expression of the proinflammatory protein transglutaminase 2 (TG2) is an important regulator of the Warburg effect in mammary epithelial cells. Mechanistically, TG2 regulated metabolic reprogramming by constitutively activating nuclear factor (NF)-κB, which binds to the hypoxia-inducible factor (HIF)-1α promoter and induces its expression even under normoxic conditions. TG2/NF-κB-induced increase in HIF-1α expression was associated with increased glucose uptake, increased lactate production and decreased oxygen consumption by mitochondria. Experimental suppression of TG2 attenuated HIF-1α expression and reversed downstream events in mammary epithelial cells. Moreover, downregulation of p65/RelA or HIF-1α expression in these cells restored normal glucose uptake, lactate production, mitochondrial respiration and glycolytic protein expression. Our results suggest that aberrant expression of TG2 is a master regulator of metabolic reprogramming and facilitates metabolic alterations in epithelial cells even under normoxic conditions. A TG2-induced shift in glucose metabolism helps breast cancer cells to survive under stressful conditions and promotes their metastatic competence.

Ergosterol and its metabolites as agonists of Liver X receptor and their anticancer potential in colorectal cancer.

Aberrant cholesterol homeostasis is a well-recognized hallmark of cancer and is implicated in metastasis as well as chemotherapeutic resistance, the two major causes of cancer associated mortality. Liver X receptors (LXRs) are the key transcription factors that induce cholesterol efflux via enhancing the expression of ABCA1 and ABCG1. Therefore, a comprehensive analysis of several novel sterols namely ergosta-7,22,24(28)-trien-3ß-ol (Erg1), ergosta-5,22,25-trien-3-ol (Erg2), ergosta-5,7,22,24(28)-tetraen-3ß-ol (Erg3), and ergosta-7,22-dien-3ß-ol (Erg4) as LXR agonists has been performed. Molecular docking studies have shown that these sterols possess higher binding affinities for LXRs as compared to the reference ligands (GW3965 and TO901317) and also formed critical activating interactions. Molecular dynamic (MD) simulations further confirmed that docking complexes made of these sterols possess significant stability. To assess the extent of LXR activation, ABCA1 promoter was cloned into luciferase reporter plasmid and transfected into HCT116 cells. It was observed that treatment with Erg, Erg2 and Erg4 led to a significant LXR activation with an EC50 of 5.64 µM, 4.83 and 3.03 µM respectively. Furthermore, a significant increase in mRNA expression of NR1H2 and LXR target genes i.e. ABCA1, ABCG1 and ApoE was observed upon Erg treatment. Flow cytometric analysis have revealed a significant increase in the accumulation of ABCA1 upon Erg treatment. Cytotoxicity studies conducted on colorectal cancer cell and normal epithelial cell line showed that these sterols are selectively toxic towards cancer cells. Taken together, our findings suggests that ergosterol activates LXRs, have significant anticancer activity and could be a likely candidate to manage aberrant cholesterol homeostasis.

Tissue transglutaminase as a central mediator in inflammation-induced progression of breast cancer.

TGM2 is a stress-responsive gene that encodes a multifunctional and structurally complex protein called tissue transglutaminase (abbreviated as TG2 or tTG). TGM2 expression is frequently upregulated during inflammation and wounding. Emerging evidence indicates that TGM2 expression is aberrantly upregulated in multiple cancer cell types, particularly those selected for resistance to chemotherapy and radiation therapy and those isolated from metastatic sites. It is becoming increasingly evident that chronic expression of TG2 in epithelial cancer cells initiates a complex series of signaling networks which contributes to the development of drug resistance and an invasive phenotype. For example, forced or basal high expression of TG2 in mammary epithelial cells is associated with activation of nuclear transcription factor-kappa B (NF-κB), Akt, focal adhesion kinase, and hypoxia-inducible factor. All of these changes are considered hallmarks of aggressive tumors. TG2 expression is able to induce the developmentally regulated program of epithelial-to-mesenchymal transition (EMT) and to confer cancer stem cell (CSC) traits in mammary epithelial cells; both EMT and CSCs have been implicated in cancer metastasis and resistance to standard therapies. Importantly, TG2 expression in tumor samples is associated with poor disease outcome, increased drug resistance, and increased incidence of metastasis. These observations imply that TG2 plays a crucial role in promoting an aggressive phenotype in mammary epithelial cells. In this review, we discuss recent evidence that TG2-regulated pathways contribute to the aggressive phenotype in breast cancer.

Alteration in apoptosis and cell cycle by celecoxib and/or fish oil in 7,12-dimethyl benzene (α) anthracene-induced mammary carcinogenesis.

Cyclooxygenase (COX)-2 inhibition by nonsteroidal anti-inflammatory drugs is a useful approach for cancer prevention but has several side effects. A novel approach combining these chemopreventive agents at low doses with dietary elements has been suggested to augment their effects and reduce side effects. Dietary fats, particularly, n-3 polyunsaturated fatty acids (PUFA) also exert cancer chemopreventive effect mediated through COX-2 inhibition. Therefore, the present study was designed to investigate the effect of combined dosage of celecoxib and n-3 PUFA-rich fish oil in experimental mammary carcinogenesis. Female Wistar rats were distributed into control and DMBA-treated groups. The groups were further subdivided based on pretreatment with celecoxib and/or fish oil. The animals were maintained for 90 days before sacrifice. To analyze the role of redox signaling, the two mediators, reactive oxygen species and calcium, and their effects on c-myc expression were evaluated. The chemopreventive effect was assessed by measurement of cell proliferation, apoptosis, and p53 in isolated mammary epithelial cells. Increased redox signaling with enhanced c-myc, p53 expression, and augmented apoptotic and proliferative rate were observed in carcinogen-treated animals. Pretreatment of carcinogen-treated animals with celecoxib and/or fish oil altered redox signaling with reduced c-myc, p53 expression, apoptosis, and proliferation. However, a combination dosage of celecoxib and fish oil had a better chemopreventive effect. The results suggest that a combination of celecoxib and fish oil is more effective in the chemoprevention of experimental mammary carcinogenesis, and this effect can be attributed to the modification of redox signaling.

Alterations in mitochondrial membrane in chemopreventive action of fish oil.

Mitochondria are major regulators of pathways related to tumorigenesis; therefore, mitochondrial membrane characteristics and associated cell signaling events were evaluated with different ratios of fish oil (FO) and corn oil (CO) in experimental colon carcinogenesis. Treatment with carcinogen 1,2-dimethylhydrazine (DMH) altered reactive oxygen species (ROS), Ca(2+), and membrane characteristics, which resulted in an elevation in apoptosis in initiation phase and reduction in post-initiation phase. FO+CO(2.5:1)+DMH treatment, however, altered mitochondrial membrane parameters, ROS, and Ca(2+) to increase apoptosis in both phases, whereas FO+CO(1:1)+DMH treatment enhanced apoptosis only in post-initiation phase suggesting that FO supplementation in higher ratio has better chemopreventive efficacy.

Dietary n-3 and n-6 polyunsaturated fatty acids differentially modulate the adiponectin and leptinmediated major signaling pathways in visceral and subcutaneous white adipose tissue in high fat diet induced obesity in Wistar rats.

Obesity is a chronic metabolic disease that involves excessive accumulation of fat in white adipose tissue (WAT). Apart from storing excess fats, WAT also serves as an important endocrine organ secreting adipocytokines such as adiponectin and leptin. Adiponectin and leptin bind to their transmembrane receptors adiponectin receptor 1 (AdipoR1)/adiponectin receptor 2 (AdipoR2) and Ob-R, respectively, and mediate their effect on metabolism by regulating multiple downstream targets. Dietary fat is considered the main culprit behind obesity development. Numerous preclinical studies have highlighted role of essential polyunsaturated fatty acids (PUFAs), particularly n-3 PUFAs, in prevention of obesity. Despite emerging data, there still is no clear understanding of the mechanism of action of n-3 PUFAs and n-6 PUFAs on adipose tissue function in two functionally and anatomically different depots of WAT: visceral and subcutaneous. We designed this study using a high fat diet (HFD) fed rodent model of obesity to test our hypothesis that n-3 and n-6 PUFAs possibly differentially modulate adipokine secretion and downstream metabolic pathways such as peroxisome proliferator-activated receptor-γ (PPAR-γ), protein kinase B (AKT)-forkhead box O1 (FOXO1), and Janus kinase-signal transducer and activator of transcription in obesity. The results of the current study showed that n-3 PUFAs upregulate the expression of AdipoR1/R2 and ameliorate the effects of HFD by modulating adipogenesis via PPAR-γ and by improving glucose tolerance and lipid metabolism via AKT-FOXO1 axis in fish oil fed rats. However, n-6 PUFAs did not show any remarkable change compared with HFD fed animals. Our study highlights that n-3 PUFAs modulate expression of various targets in adiponectin and leptin signaling cascade, bringing about an overall reduction in obesity and improvement in adipose tissue function in HFD induced obesity.

Targeting fuel pocket of cancer cell metabolism: A focus on glutaminolysis.

Advances in cell metabolism over the past few decades have demonstrated glutamine as an essential nutrient for cancer cell survival and proliferation. Glutamine offers a remarkable capacity to fuel diverse metabolic pathways in cancer cells including the Krebs cycle, maintenance of redox homeostasis, and synthesis of cellular building blocks such as nucleic acids, fatty acids, glutathione, and other amino acids. The increase in glutaminolysis has further been linked to the accumulation of oncometabolites such as 2HG (2-Hydroxyglutarate), succinate, fumarate, etc., thereby contributing to tumorigenesis via regulating epigenetic modification of imprinted genes. Therefore, therapeutic targeting of glutaminolysis in cancer cells is worth exploring for possible treatment strategies for cancer management. In this review, we have discussed the detailed mechanism of glutamine uptake, transport, and its instrumental role in rewiring the metabolic adaptation of cancer cells in the tumor microenvironment under nutrient deprivation and hypoxia. Furthermore, we have attempted to provide an updated therapeutic intervention of glutamine metabolism as a treatment strategy for cancer management.

Clinical relevance of CERK and SPHK1 in breast cancer and their association with metastasis and drug resistance.

Despite numerous reports on the altered sphingolipids metabolism in human cancers, their clinical significance in breast cancer remains obscure. Previously, we identified the high levels of sphingolipids, ceramide phosphates and sphingosine phosphates, and the genes involved in their synthesis, CERK and SPHK1, in breast cancer patients. The present study aimed to determine the correlations of CERK and SPHK1 with clinical outcomes as well as metastasis and drug resistance markers. Both local and TCGA cohorts were analysed. High-confidence regulatory interaction network was constructed to find association of target genes with metastasis and drug resistance. Furthermore, correlations of CERK and SPHK1 with selected metastasis and drug resistance markers were validated in both cohorts. Overexpression of CERK and SPHK1 was associated with nodal metastasis, late tumor stage and high proliferation potency. In addition, increased CERK expression was also indicative of poor patient survival. Computational network analysis revealed the association of CERK and SPHK1 with known metastasis markers MMP-2 and MMP-9 and drug resistance markers ABCC1 and ABCG2. Correlation analysis confirmed the associations of target genes with these markers in both local as well as TCGA cohort. The above findings suggest clinical utility of CERK and SPHK1 as potential biomarkers in breast cancer patients and thus could provide novel leads in the development of therapeutics.

Evaluation of the role of oxidative stress in chemopreventive action of fish oil and celecoxib in the initiation phase of 7,12-dimethyl benz(α)anthracene-induced mammary carcinogenesis.

Cyclooxygenase-2 (COX-2) enzyme plays an important role in cancer development. COX-2 inhibition by non-steroidal anti-inflammatory drugs is a useful approach for cancer prevention, but its usage has been associated with side effects. n-3 polyunsaturated fatty acids also exhibit a chemopreventive effect mediated by COX-2 inhibition. Therefore, the present study was designed to evaluate the effect of combined dosage of celecoxib and fish oil in experimental mammary carcinogenesis. Female Wistar rats were distributed as control, 7,12-dimethyl benz(α)anthracene (DMBA) treated, celecoxib + fish oil (20 mg/kg b.w. + 0.5 ml), celecoxib + fish oil (30 mg/kg b.w. + 0.25 ml), and their corresponding controls treated with fish oil or celecoxib only. The treatment was given for 7 days, and on the 8th day animals of all the groups except the control group received DMBA orally and sacrificed after 90 days. The histopathology, DNA fragmentation, total sialic acid (TSA), lipid-associated sialic acid (LASA), and oxidative stress were measured in mammary tissue and liver mitochondrial fraction. The results showed ductal hyperplasia and an increase in TSA, LASA, lipid peroxidation, and nitrite levels with a decrease in the antioxidants on DMBA treatment. Pretreatment with celecoxib and fish oil in DMBA-treated animals led to normal histology, increase in DNA fragmentation, and decrease in TSA and LASA levels with reduced oxidative stress, and the effect was more pronounced than animals pretreated with either celecoxib/fish oil alone suggesting a synergistic effect of the two regimens. To conclude, a combination of celecoxib and fish oil is a better strategy for cancer chemoprevention than celecoxib/fish oil alone.

Expression of miR-18a-5p, miR-144-3p, and miR-663b in colorectal cancer and their association with cholesterol homeostasis.

OBJECTIVE: Though cholesterol accumulation is an established hallmark of a tumor cell, the relationship between the two is still not clear. Previously, we identified 3-Hydroxy-3-Methylglutaryl-CoA Reductase (HMGCR), Sterol Regulatory Element BindingTranscription Factor 2 (SREBF2), Nuclear Receptor Subfamily 1 Group H Member 3 (NR1H3), and Nuclear Receptor Subfamily 1 Group H Member 2 (NR1H2) as the key cholesterol homeostasis genes involved in colorectal cancer (CRC). In the present study, we aimed to identify microRNAs regulating these key genes in CRC. METHODS: miR-18a-5p, miR-144-3p, and miR-663b were selected as the miRNAs targeting NR1H2, HMGCR, and SREBF2, respectively, based on the bioinformatic prediction tools and literature review. Their expression was evaluated in the local and The Cancer Genome Atlas (TCGA) cohorts. Receiver Operating Characteristic Curves and Kaplan Meier analysis were performed to elucidate their diagnostic and prognostic potential. Pearson or Spearman's correlations were used to evaluate the relationship between miRNAs and their target genes. Protein-protein interaction networks and Gene Ontology analyses were performed to investigate the potential molecular mechanism of these miRNAs. RESULTS: Deregulated expression of miR-18a-5p, miR-144-3p, and miR-663b was associated with various clinicopathological features. miR-18a-5p exhibited an inverse correlation with NR1H2. miR-18a-5p and miR-144-3p also had a significant direct correlation with miR-33a-5p, an important modulator of cholesterol homeostasis. These miRNAs also exhibited high centrality in the mirna-protein interaction network. miR-144-3p and miR-663b exhibited the potential to be used as diagnostic biomarkers. CONCLUSIONS: miR-18a-5p and miR-144-3p exhibited the potential to modulate cholesterol homeostasis in CRC. miR-663b is an interesting candidate in CRC pathophysiology.