The role of NAG-1/GDF15 in the inhibition of intestinal polyps in APC/Min mice by sulindac

The Role of GDF15 in Regulating the Canonical Pathways of the Tumor Microenvironment in Wild-Type p53 Ovarian Tumor and Its Response to Chemotherapy

Simple Summary

Patients with wild-type p53 ovarian cancer appear to have a poorer survival rate than those with mutant p53 due to resistance to chemotherapy. The mechanism underlying this observation is not clearly understood. The aim of this study was to identify potential biomarkers regulated by p53 that conferred resistance using in vitro and in vivo studies. Growth differentiation factor 15 (GDF15) expression was demonstrated to be controlled by p53 in both ovarian cancer cell lines and orthotopic mouse models. The histological and RNAseq studies of the GDF15-knocked down, A2780 cell line-induced tumor revealed that the ratio and canonical pathways of stromal/tumor were modified by secretory GDF15.

Abstract

Background: The standard treatment of ovarian cancer is surgery followed by a chemotherapeutic combination consisting of a platinum agent, such as cisplatin and a taxane-like paclitaxel. We previously observed that patients with ovarian cancer wild-type for p53 had a poorer survival rate than did those with p53 mutations. Thus, a better understanding of the molecular changes of epithelial ovarian cancer cells with wild-type p53 in response to treatment with cisplatin could reveal novel mechanisms of chemoresistance. Methods: Gene expression profiling was performed on an ovarian cancer cell line A2780 with wild-type p53 treated with cisplatin. A gene encoding a secretory protein growth differentiation factor 15 (GDF15) was identified to be highly induced by cisplatin treatment in vitro. This was further validated in a panel of wild-type and mutant p53 ovarian cancer cell lines, as well as in mouse orthotopic models. The mouse tumor tissues were further analyzed by histology and RNA-seq. Results: GDF15 was identified as one of the highly induced genes by cisplatin or carboplatin in ovarian cancer cell lines with wild-type p53. The wild-type p53-induced expression of GDF15 and GDF15-confered chemotherapy resistance was further demonstrated in vitro and in vivo. This study also discovered that GDF15-knockdown (GDF15-KD) tumors had less stromal component and had different repertoires of activated and inhibited canonical pathways in the stromal cell and cancer cell components from that of the control tumors after cisplatin treatment. Conclusions: GDF15 expression from the wild-type p53 cancer cells can modulate the canonical pathways in the tumor microenvironment in response to cisplatin, which is a possible mechanism of chemoresistance.

Anthocyanin Encapsulated by Ferulic Acid-Grafted-Maltodextrin (FA-g-MD) Microcapsules Potentially Improved its Free Radical Scavenging Capabilities Against H2O2-Induced Oxidative Stress

This study aimed to investigate the antioxidant activity and release behavior of anthocyanin (ANC) loaded within FA-g-MD wall (ANC-FA-g-MD microcapsule) in vitro. The microencapsulation of ANC was prepared by spray drying and displayed a biphasic release profile. The combination of ANC and FA-g-MD (0.0625–1 mg/mL) showed a higher antioxidant activity than that of both individuals. A possible intermolecular interaction between ANC and FA-g-MD was studied by UV-vis spectra. Intracellular reactive oxygen species (ROS), 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, and protein expression of quinone oxidoreductase 1(NQO1), glutathione reductase (GSR) and γ-glutamate cysteine ligase catalytic subunit (γ-GCLC) were measured through human colon cancer cells (HT-29). After a 24-hour incubation of the HT-29, the combinations (0–60 μg/mL) exhibited a high potential to diminish the ROS level. And the distinct upregulated expressions of GCLC and NQO1 of HT-29 were detected after treatment with combinations compared to those of single ones. These results suggested that the ANC-FA-g-MD microcapsules exerts enhanced antioxidant effect with capability of the modulation of GCLC and NQO1.

Cancer-preventive Properties of an Anthocyanin-enriched Sweet Potato in the APCMIN Mouse Model

Background

Anthocyanin-rich foods and preparations have been reported to reduce the risk of life-style related diseases, including cancer. The SL222 sweet potato, a purple-fleshed cultivar developed in New Zealand, accumulates high levels of anthocyanins in its storage root.

Methods

We examined the chemopreventative properties of the SL222 sweet potato in the C57BL/6J-APC^MIN/+ (APC^MIN) mouse, a genetic model of colorectal cancer. APC^MIN and C57BL/6J wild-type mice (n=160) were divided into four feeding groups consuming diets containing 10% SL222 sweet potato flesh, 10% SL222 sweet potato skin, or 0.12% ARE (Anthocyanin rich-extract prepared from SL222 sweet potato at a concentration equivalent to the flesh-supplemented diet) or a control diet (AIN-76A) for 18 weeks. At 120 days of age, the mice were anaesthetised, and blood samples were collected before the mice were sacrificed. The intestines were used for adenoma enumeration.

Results

The SL222 sweet potato-supplemented diets reduced the adenoma number in the APC^MIN mice.

Conclusions

These data have significant implications for the use of this sweet potato variant in protection against colorectal cancer.

Macrophage inhibitory cytokine-1/growth differentiation factor-15 as a predictor of colonic neoplasia

BACKGROUND

Serum macrophage inhibitory cytokine-1 (MIC-1/GDF15) concentration has been associated with colonic adenomas and carcinoma.

AIMS

To determine whether circulating MIC-1/GDF15 serum concentrations are higher in the presence of adenomas and whether the level decreases after excision.

METHODS

Patients were recruited prospectively from a single centre and stratified into five groups: no polyps (NP); hyperplastic polyps (HP); sessile serrated ademona (SSA); adenomas (AP); and colorectal carcinoma (CRC). Blood samples were collected immediately before and 4 weeks after colonoscopy. MIC-1/GDF15 serum levels were quantified using ELISA.

RESULTS

Participants (n=301) were stratified as: NP; n=116 (52%), HP; n=37 (12%), SSA; n=19 (7%), AP; n=68 (23%); and CRC; n=3 (1%). Patients were excluded from the study due to nondiagnostic pathology (n=9, 3%) and exclusion criteria (n=20, 6%). In the 272 remaining subjects (M=149; F=123), age (P=.005), history of colonic polyps (P=.003) and family history of colonic polyps (P=.002) were associated with presence of adenomas. Baseline median MIC-1/GDF15 serum levels increased significantly from NP 609 (460-797) pg/mL, HP 582 (466-852) pg/mL, SSA 561 (446-837) pg/mL to AP 723 (602-1122) pg/mL and CRC 1107 (897-1107) pg/mL; (P<.001). In the pre- and postpolypectomy paired adenoma samples median MIC-1/GDF15 reduced significantly from 722 (603-1164) pg/mL to 685 (561-944) pg/mL (P=.002). A ROC analysis for serum MIC-1/GDF15 to identify adenomatous polyps indicated an area under the curve of 0.71.

CONCLUSIONS

Our data suggest that serum MIC-1/GDF15 has the diagnostic characteristics to increase the detection of colonic neoplasia and improve screening.

ASPirin Intervention for the REDuction of colorectal cancer risk (ASPIRED): a study protocol for a randomized controlled trial

BACKGROUND

Although aspirin is recommended for the prevention of colorectal cancer, the specific individuals for whom the benefits outweigh the risks are not clearly defined. Moreover, the precise mechanisms by which aspirin reduces the risk of cancer are unclear. We recently launched the ASPirin Intervention for the REDuction of colorectal cancer risk (ASPIRED) trial to address these uncertainties.

METHODS/DESIGN

ASPIRED is a prospective, double-blind, multidose, placebo-controlled, biomarker clinical trial of aspirin use in individuals previously diagnosed with colorectal adenoma. Individuals (n = 180) will be randomized in a 1:1:1 ratio to low-dose (81 mg/day) or standard-dose (325 mg/day) aspirin or placebo. At two study visits, participants will provide lifestyle, dietary and biometric data in addition to urine, saliva and blood specimens. Stool, grossly normal colorectal mucosal biopsies and cytology brushings will be collected during a flexible sigmoidoscopy without bowel preparation. The study will examine the effect of aspirin on urinary prostaglandin metabolites (PGE-M; primary endpoint), plasma inflammatory markers (macrophage inhibitory cytokine-1 (MIC-1)), colonic expression of transcription factor binding (transcription factor 7-like 2 (TCF7L2)), colonocyte gene expression, including hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD) and those that encode Wnt signaling proteins, colonic cellular nanocytology and oral and gut microbial composition and function.

DISCUSSION

Aspirin may prevent colorectal cancer through multiple, interrelated mechanisms. The ASPIRED trial will scrutinize these pathways and investigate putative mechanistically based risk-stratification biomarkers.

TRIAL REGISTRATION

This protocol is registered with the U.S. National Institutes of Health trial registry, ClinicalTrials.gov, under the identifier NCT02394769 . Registered on 16 March 2015.

Association Between Plasma Levels of Macrophage Inhibitory Cytokine-1 Before Diagnosis of Colorectal Cancer and Mortality

BACKGROUND & AIMS

Patients with colorectal cancer (CRC) have high circulating levels of macrophage inhibitory cytokine-1 (MIC1 or growth differentiation factor 15), a marker of inflammation that might be involved in carcinogenesis. We analyzed blood samples collected from individuals before they were diagnosed with CRC to determine whether levels of MIC1 were associated with mortality.

METHODS

We collected data on survival of 618 participants diagnosed with CRC who provided prediagnosis blood specimens in 1990 (Nurses' Health Study) and 1994 (Health Professionals' Follow-up Study) and were followed through 2010. Levels of MIC1 were measured by enzyme-linked immunosorbent assay and then were categorized into quartiles based on the known distribution of MIC1 levels among previously matched individuals without CRC (controls) within each cohort. We then examined the association of MIC1 levels with overall and CRC-specific mortality using Cox proportional hazards models, with adjustments for mortality-associated risk factors and other plasma markers of inflammation. We also assessed the relationship between levels of MIC1 and levels of prostaglandin-endoperoxide synthase 2 expression (PTGS2 or cyclooxygenase-2), measured in 245 tumor samples by immunohistochemistry.

RESULTS

Compared with participants in the lowest quartile for plasma level of MIC1, the multivariate hazard ratio for CRC-specific death for participants in the highest quartile of MIC1 level was 2.40 (95% confidence interval: 1.33-4.34; P for linear trend = .009). The association of MIC1 with survival varied with level of PTGS2 expression in tumor samples (Pinteraction = .04). For individuals with PTGS2-positive tumors, the hazard ratio for CRC-specific death among those with high levels of MIC1 (equal to or greater than the median) was 2.13 (95% confidence interval: 0.99-4.58) compared with participants with low levels of MIC1 (below the median). In individuals with PTGS2-negative CRC, a high level of MIC1 was not associated with an increased risk of CRC-specific death (multivariate hazard ratio = 0.61; 95% confidence interval: 0.13-2.93).

CONCLUSIONS

Based on an analysis of blood and colorectal tumor samples from 2 large studies, high plasma levels of MIC1 (growth differentiation factor 15) before diagnosis of CRC are associated with greater CRC-specific mortality, particularly in individuals with PTGS2-positive tumors.

NSAIDs and Colorectal Cancer Control: Promise and Challenges

The chemoprevention of colorectal cancer (CRC) is a realistic option given the low acceptance and cost of screening colonoscopy. NSAIDs, currently not recommended for CRC prevention, are the most promising agents. Here, we review relevant work and assess the chemopreventive potential of NSAIDs. The chemopreventive efficacy of NSAIDs is established by epidemiological and interventional studies as well as analyses of cardiovascular-prevention randomized clinical trials. The modest chemopreventive efficacy of NSAIDs is compounded by their significant toxicity that can be cumulative. Efforts to overcome these limitations include the use of drug combinations; the emphasis on the early stages of colon carcinogenesis such as aberrant crypt foci, which may require shorter periods of drug administration; and the development of several families of chemically modified NSAIDs such as derivatives of sulindac, nitro-NSAIDs and phospho-NSAIDs, with some of them appearing to have higher safety and efficacy than conventional NSAIDs and thus to be better candidate agents. The successful development of NSAIDs as chemopreventive agents will likely require a combination of the following: identification of subjects at high risk and/or those most likely to benefit from chemoprevention; optimization of the timing, dose and duration of administration of the chemopreventive agent; novel NSAID derivatives and/or combinations of agents; and agents that may prevent other diseases in addition to CRC. Ultimately, the clinical implementation of NSAIDs for the prevention of CRC will depend on a strategy that drastically shifts the currently unacceptable risk/benefit ratio in favor of chemoprevention.

The evolving role of nonsteroidal anti-inflammatory drugs in colon cancer prevention: a cause for optimism

Colorectal cancer (CRC) is a serious yet preventable disease. The low acceptance and cost of colonoscopy as a screening method or CRC make chemoprevention an important option. Nonsteroidal anti-inflammatory drugs (NSAIDs), not currently recommended for CRC prevention, have the potential to evolve into the agents of choice for this indication. Here, we discuss the promise and challenge of NSAIDs for this chemopreventive application.Multiple epidemiologic studies, randomized clinical trials (RCTs) of sporadic colorectal polyp recurrence, RCTs in patients with hereditary colorectal cancer syndromes, and pooled analyses of cardiovascular-prevention RCTs linked to cancer outcomes have firmly established the ability of conventional NSAIDs to prevent CRC. NSAIDs, however, are seriously limited by their toxicity,which can become cumulative with their long-term administration for chemoprevention, whereas drug interactions in vulnerable elderly patients compound their safety. Newer, chemically modified NSAIDs offer the hope of enhanced efficacy and safety.Recent work also indicates that targeting earlier stages of colorectal carcinogenesis, such as the lower complexity aberrant crypt foci, is a promising approach that may only require relatively short use of chemopreventive agents. Drug combination approaches exemplified by sulindac plus difluoromethylornithine appear very efficacious. Identification of those at risk or most likely to benefit from a given intervention using predictive biomarkers may usher in personalized chemoprevention. Agents that offer simultaneous chemoprevention of diseases in addition to CRC, e.g., cardiovascular and/or neurodegenerative diseases,may have a much greater potential for a broad clinical application.

Reduced expression of GDF-15 is associated with atrophic inflammatory lesions of the prostate

BACKGROUND

Accumulating evidence suggests that chronic prostatic inflammation may lead to prostate cancer development. Growth differentiation factor-15 (GDF-15) is highly expressed in the prostate and has been associated with inflammation and tumorigenesis.

METHODS

To examine the relationship between GDF-15 and prostatic inflammation, GDF-15 expression was measured by immunohistochemical (IHC) staining in human prostatectomy specimens containing inflammation. The relationship between GDF-15 and specific inflammatory cells was determined using non-biased computer image analysis. To provide insight into a potential suppressive role for GDF-15 in inflammation, activation of inflammatory mediator nuclear factor of kappa B (NFκB) was measured in PC3 cells.

RESULTS

GDF-15 expression in luminal epithelial cells was decreased with increasing inflammation severity, suggesting an inverse association between GDF-15 and inflammation. Quantification of IHC staining by image analysis for GDF-15 and inflammatory cell markers revealed an inverse correlation between GDF-15 and CD3+, CD4+, CD8+, CD68+, and inos+ leukocytes. GDF-15 suppressed NFκB activity in luciferase reporter assays. Expression of the NFκB target, interleukin 8 (IL-8), was downregulated by GDF-15.

CONCLUSIONS

The inverse relationship between GDF-15 and inflammation demonstrates a novel expression pattern for GDF-15 in the human prostate and suppression of NFκB activity may shed light on a potential mechanism for this inverse correlation.

Ginger compound [6]-shogaol and its cysteine-conjugated metabolite (M2) activate Nrf2 in colon epithelial cells in vitro and in vivo

In this study, we identified Nrf2 as a molecular target of [6]-shogaol (6S), a bioactive compound isolated from ginger, in colon epithelial cells in vitro and in vivo. Following 6S treatment of HCT-116 cells, the intracellular GSH/GSSG ratio was initially diminished but was then elevated above the basal level. Intracellular reactive oxygen species (ROS) correlated inversely with the GSH/GSSG ratio. Further analysis using gene microarray showed that 6S upregulated the expression of Nrf2 target genes (AKR1B10, FTL, GGTLA4, and HMOX1) in HCT-116 cells. Western blotting confirmed upregulation, phosphorylation, and nuclear translocation of Nrf2 protein followed by Keap1 decrease and upregulation of Nrf2 target genes (AKR1B10, FTL, GGTLA4, HMOX1, and MT1) and glutathione synthesis genes (GCLC and GCLM). Pretreatment of cells with a specific inhibitor of p38 (SB202190), PI3K (LY294002), or MEK1 (PD098059) attenuated these effects of 6S. Using ultra-high-performance liquid chromatography-tandem mass spectrometry, we found that 6S modified multiple cysteine residues of Keap1 protein. In vivo 6S treatment induced Nrf2 nuclear translocation and significantly upregulated the expression of MT1, HMOX1, and GCLC in the colon of wild-type mice but not Nrf2(-/-) mice. Similar to 6S, a cysteine-conjugated metabolite of 6S (M2), which was previously found to be a carrier of 6S in vitro and in vivo, also activated Nrf2. Our data demonstrated that 6S and its cysteine-conjugated metabolite M2 activate Nrf2 in colon epithelial cells in vitro and in vivo through Keap1-dependent and -independent mechanisms.

Effect of glycosylation patterns of Chinese eggplant anthocyanins and other derivatives on antioxidant effectiveness in human colon cell lines

In this study, we compared the scavenging ROS of anthocyanins from Chinese eggplant var. Niu Jiao Qie and other delphinidin derivatives with different glycosylation patterns in HT-29 and HCT-116 cell lines. The eggplant anthocyanins were isolated and identified using LC-MSn and (1)H/(13)C NMR as delphinidin-3-[(4"-trans-p-coumaroyl)-rhamnosyl (1 → 6)glucoside]-5-glucoside, also known as nasunin. Delphinidin derivatives with glycosylation only on C3 (delphinidin-3-glucoside, 3-sambubioside, or 3-rutinoside) exhibited greater effects on ROS reduction as compared to delphinidin derivatives that have glycosylation on C3 and C5 (delphinidin-3,5-diglucoside>delphinidin-3-rutinoside-5-glucoside). Nasunin has glycosylation on C3 and C5 and an acyl group (p-coumaric acid), demonstrated the least effect on ROS reduction. Meanwhile, their ROS reduction activities were consistent with glutathione reductase protein expression levels in HT-29. Although not potent in ROS reduction, nasunin and its deacylated derivatives protected cells from DNA damage in a dose-dependent manner. Taken together, our results suggest that the anthocyanins isolated from Chinese eggplant var. Niu Jiao Qie and other delphinidin have antioxidant activities in colon cancer cells and also protect cells from DNA damage.

Growth differentiation factor-15 (GDF-15) suppresses in vitro angiogenesis through a novel interaction with connective tissue growth factor (CCN2)

Growth differentiation factor-15 (GDF-15) and the CCN family member, connective tissue growth factor (CCN2), are associated with cardiac disease, inflammation, and cancer. The precise role and signaling mechanism for these factors in normal and diseased tissues remains elusive. Here we demonstrate an interaction between GDF-15 and CCN2 using yeast two-hybrid assays and have mapped the domain of interaction to the von Willebrand factor type C domain of CCN2. Biochemical pull down assays using secreted GDF-15 and His-tagged CCN2 produced in PC-3 prostate cancer cells confirmed a direct interaction between these proteins. To investigate the functional consequences of this interaction, in vitro angiogenesis assays were performed. We demonstrate that GDF-15 blocks CCN2-mediated tube formation in human umbilical vein endothelial (HUVEC) cells. To examine the molecular mechanism whereby GDF-15 inhibits CCN2-mediated angiogenesis, activation of αV β3 integrins and focal adhesion kinase (FAK) was examined. CCN2-mediated FAK activation was inhibited by GDF-15 and was accompanied by a decrease in αV β3 integrin clustering in HUVEC cells. These results demonstrate, for the first time, a novel signaling pathway for GDF-15 through interaction with the matricellular signaling molecule CCN2. Furthermore, antagonism of CCN2 mediated angiogenesis by GDF-15 may provide insight into the functional role of GDF-15 in disease states.

A prospective study of macrophage inhibitory cytokine-1 (MIC-1/GDF15) and risk of colorectal cancer

BACKGROUND

Chronic inflammation plays a role in the development of colorectal cancer (CRC). The novel plasma inflammatory biomarker macrophage inhibitory cytokine-1 (MIC-1, GDF15) may have a direct mechanistic role in colorectal carcinogenesis.

METHODS

We conducted a prospective, nested, case-control study of incident CRC among men and women who provided a prediagnostic blood specimen. We used an enzyme-linked immunosorbent assay to measure MIC-1 and examined associations between quintiles of MIC-1 and CRC using logistic regression adjusted for matching factors (age and date of blood draw), risk factors, and other plasma inflammatory markers. We also assessed the relationship between MIC-1 levels and prostaglandin-endoperoxide synthase 2 (PTGS2)/cyclooxygenase-2 (COX-2) enzyme status in tumors with available tissue for analysis. All statistical tests were two-sided.

RESULTS

Compared with men and women within the lowest quintile of plasma MIC-1, the multivariable relative risk (RR) for CRC was 1.93 (95% confidence interval [CI] = 1.27 to 2.94) for the highest quintile (P linear trend = .004). In an exploratory analysis, we found that among individuals with high plasma MIC-1 levels (quintiles 2-5), compared with nonuse, regular use of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) was associated with a lower risk of PTGS2-positive CRC (multivariable RR = 0.60; 95% confidence interval = 0.41 to 0.88) but not PTGS2-negative CRC (multivariable RR = 1.21; 95% CI = 0.71 to 2.07). In contrast, among individuals with low MIC-1 levels (quintile 1), aspirin and NSAID use was not associated with a lower risk of PTGS2-positive CRC (multivariable RR = 0.57; 95% CI = 0.21 to 1.54) or PTGS2-negative CRC (multivariable RR = 1.41; 95% CI = 0.47 to 4.23).

CONCLUSIONS

Our results support an association between higher levels of circulating MIC-1 (GDF15) and CRC. Aspirin/NSAID use appeared to lower risk of PTGS2-positive cancers, particularly among individuals with high levels of circulating MIC-1.

NSAIDs inhibit tumorigenesis, but how?

Numerous epidemiologic studies have reported that the long-term use of nonsteroidal anti-inflammatory drugs (NSAID) is associated with a significant decrease in cancer incidence and delayed progression of malignant disease. The use of NSAIDs has also been linked with reduced risk from cancer-related mortality and distant metastasis. Certain prescription-strength NSAIDs, such as sulindac, have been shown to cause regression of precancerous lesions. Unfortunately, the extended use of NSAIDs for chemoprevention results in potentially fatal side effects related to their COX-inhibitory activity and suppression of prostaglandin synthesis. Although the basis for the tumor growth-inhibitory activity of NSAIDs likely involves multiple effects on tumor cells and their microenvironment, numerous investigators have concluded that the underlying mechanism is not completely explained by COX inhibition. It may therefore be possible to develop safer and more efficacious drugs by targeting such COX-independent mechanisms. NSAID derivatives or metabolites that lack COX-inhibitory activity, but retain or have improved anticancer activity, support this possibility. Experimental studies suggest that apoptosis induction and suppression of β-catenin-dependent transcription are important aspects of their antineoplastic activity. Studies show that the latter involves phosphodiesterase inhibition and the elevation of intracellular cyclic GMP levels. Here, we review the evidence for COX-independent mechanisms and discuss progress toward identifying alternative targets and developing NSAID derivatives that lack COX-inhibitory activity but have improved antineoplastic properties.

Nonsteroidal anti-inflammatory drug sulindac sulfide suppresses structural protein Nesprin-2 expression in colorectal cancer cells

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are well known for treating inflammatory disease and have been reported to have anti-tumorigenic effects. Their mechanisms are not fully understood, but both cyclooxygenase (COX) dependent and independent pathways are involved. Our goal was to shed further light on COX-independent activity.

METHODS

Human colorectal cancer cells were observed under differential interference contrast microscopy (DICM), fluorescent microscopy, and micro-impedance measurement. Microarray analysis was performed using HCT-116 cells treated with sulindac sulfide (SS). PCR and Western blots were performed to confirm the microarray data and immunohistochemistry was performed to screen for Nesprin-2 expression. Micro-impedance was repeating including Nesprin-2 knock-down by siRNA.

RESULTS

HCT-116 cells treated with SS showed dramatic morphological changes under DICM and fluorescent microscopy, as well as weakened cellular adhesion as measured by micro-impedance. Nesprin-2 was selected from two independent microarrays, based on its novelty in relation to cancer and its role in cell organization. SS diminished Nesprin-2 mRNA expression as assessed by reverse transcriptase and real time PCR. Various other NSAIDs were also tested and demonstrated that inhibition of Nesprin-2 mRNA was not unique to SS. Additionally, immunohistochemistry showed higher levels of Nesprin-2 in many tumors in comparison with normal tissues. Further micro-impedance experiments on cells with reduced Nesprin-2 expression showed a proportional loss of cellular adhesion.

CONCLUSIONS

Nesprin-2 is down-regulated by NSAIDs and highly expressed in many cancers.

GENERAL SIGNIFICANCE

Our data suggest that Nesprin-2 may be a potential novel oncogene in human cancer cells and NSAIDs could decrease its expression.

Mouse models for colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related death in the United States, with the number of affected people increasing. There are many risk factors that increase CRC risk, including family or personal history of CRC, smoking, consumption of red meat, obesity, and alcohol consumption. Conversely, increased screening, maintaining healthy body weight, not smoking, and limiting intake of red meat are all associated with reduced CRC morbidity and mortality. Mouse models of CRC were first used in 1928 and have played an important role in understanding CRC biology and treatment and have long been instrumental in clarifying the pathobiology of CRC formation and inhibition. This review focuses on advancements in modeling CRC in mice.

The diverse roles of nonsteroidal anti-inflammatory drug activated gene (NAG-1/GDF15) in cancer

Nonsteroidal anti-inflammatory drug (NSAID) activated gene-1, NAG-1, is a divergent member of the transforming growth factor-beta (TGF-β) superfamily that plays a complex but poorly understood role in several human diseases including cancer. NAG-1 expression is substantially increased during cancer development and progression especially in gastrointestinal, prostate, pancreatic, colorectal, breast, melanoma, and glioblastoma brain tumors. Aberrant increases in the serum levels of secreted NAG-1 correlate with poor prognosis and patient survival rates in some cancers. In contrast, the expression of NAG-1 is up-regulated by several tumor suppressor pathways including p53, GSK-3β, and EGR-1. NAG-1 expression is also induced by many drugs and dietary compounds which are documented to prevent the development and progression of cancer in mouse models. Studies with transgenic mice expressing human NAG-1 demonstrated that the expression of NAG-1 inhibits the development of intestinal tumors and prostate tumors in animal models. Laboratory and clinical evidence suggest that NAG-1, like other TGF-β family members, may have different or pleiotropic functions in the early and late stages of carcinogenesis. Upon understanding the molecular mechanism and function of NAG-1 during carcinogenesis, NAG-1 may serve as a potential biomarker for the diagnosis and prognosis of cancer and a therapeutic target for the inhibition and treatment of cancer development and progression.

Sulindac sulfide--induced stimulation of eryptosis

BACKGROUND

Sulindac sulfide, a non-steroidal anti-inflammatory drug (NSAID), stimulates apoptosis of tumor cells and is thus effective against malignancy. In analogy to apoptosis of nucleated cells, erythrocytes may undergo eryptosis, an apoptosis-like suicidal erythrocyte death, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine-exposure at the cell surface. Stimulators of eryptosis include increase of cytosolic Ca(2+)-activity ([Ca(2+)](i)) and ceramide formation. The present study explored, whether sulindac sulfide stimulates eryptosis.

METHODS

[Ca(2+)](i) was estimated from Fluo-3 fluorescence, cell volume from forward scatter, phosphatidylserine-exposure from binding of fluorescent annexin-V, hemolysis from hemoglobin release, and ceramide abundance utilizing fluorescent antibodies.

RESULTS

A 48 h exposure to sulindac sulfide (≤ 20 µM) was followed by significant increase of [Ca(2+)](i), enhanced ceramide abundance, decreased forward scatter and increased percentage of annexin-V-binding erythrocytes. Sulindac sulfide triggered slight but significant hemolysis. Removal of extracellular Ca(2+) significantly blunted, but did not abrogate the effect of sulindac sulfide (20 µM) on annexin-V-binding.

CONCLUSION

Sulindac sulfide stimulates the suicidal death of erythrocytes or eryptosis, an effect paralleled by Ca(2+)-entry, ceramide formation, cell shrinkage and phosphatidylserine-exposure.

COX inhibitors directly alter gene expression: role in cancer prevention?

Inflammation is an important contributor to the development and progression of human cancers. Inflammatory lipid metabolites, prostaglandins, formed from arachidonic acid by prostaglandin H synthases commonly called cyclooxygenases (COXs) bind to specific receptors that activate signaling pathways driving the development and progression of tumors. Inhibitors of prostaglandin formation, COX inhibitors, or nonsteroidal anti-inflammatory drugs (NSAIDs) are well documented as agents that inhibit tumor growth and with long-term use prevent tumor development. NSAIDs also alter gene expression independent of COX inhibition and these changes in gene expression also appear to contribute to the anti-tumorigenic activity of these drugs. Many NSAIDs, as illustrated by sulindac sulfide, alter gene expressions by altering the expression or phosphorylation status of the transcription factors specificity protein 1 and early growth response-1 with the balance between these two events resulting in increases or decreases in specific target genes. In this review, we have summarized and discussed the various genes altered by this mechanism after NSAID treatment and how these changes in expression relate to the anti-tumorigenic activity. A major focus of the review is on NSAID-activated gene (NAG-1) or growth differentiation factor 15. This unique member of the TGF-β superfamily is highly induced by NSAIDs and numerous drugs and chemicals with anti-tumorigenic activities. Investigations with a transgenic mouse expressing the human NAG-1 suggest it acts to suppress tumor development in several mouse models of cancer. The biochemistry and biology of NAG-1 were discussed as potential contributor to cancer prevention by COX inhibitors.

Target delivery and controlled release of the chemopreventive drug sulindac by using an advanced layered double hydroxide nanomatrix formulation system

Target delivery and controlled release of the chemopreventive drug sulindac that possesses low water solubility present a great challenge for its pharmaceutical industry. Here, we offered an advanced nanomatrix formulation system of sulindac based on layered double hydroxide materials. The X-ray analysis and infrared spectroscopy confirmed the incorporation of sulindac into the gallery of the layered double hydroxides. The incorporation ratios of sulindac were recorded to be 45, 31 and 20 for coprecipitation, anion-exchange and reconstruction techniques, respectively. The scanning electron microscopy showed a nanomatrix-structure of ~50 nm. The release studies of sulindac-nanomatrix showed a 96% controlled release at the small intestine solution during 3 h(s), indicating an enhancement in the dissolution profile of sulindac after the matrix formation. The layered structure of the matrix supplied sulindac with a well-ordered structure and a relatively hydrophobic microenvironment that controlled the guest hydrolysis and reactivity during the release process. The laminar structure of layered double hydroxides offered a safe preservation for sulindac against photodecarboxylation, and enhanced the drug thermal stability from 190 to 230° C. The ionic electrostatic interaction of sulindac through its acidic group with layered double hydroxides demolished the gastrointestinal ulceration.

Cyclooxygenase-1-selective inhibitors based on the (E)-2'-des-methyl-sulindac sulfide scaffold

Prostaglandins (PGs) are powerful lipid mediators in many physiological and pathophysiological responses. They are produced by oxidation of arachidonic acid (AA) by cyclooxygenases (COX-1 and COX-2) followed by metabolism of endoperoxide intermediates by terminal PG synthases. PG biosynthesis is inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs). Specific inhibition of COX-2 has been extensively investigated, but relatively few COX-1-selective inhibitors have been described. Recent reports of a possible contribution of COX-1 in analgesia, neuroinflammation, or carcinogenesis suggest that COX-1 is a potential therapeutic target. We designed, synthesized, and evaluated a series of (E)-2'-des-methyl-sulindac sulfide (E-DMSS) analogues for inhibition of COX-1. Several potent and selective inhibitors were discovered, and the most promising compounds were active against COX-1 in intact ovarian carcinoma cells (OVCAR-3). The compounds inhibited tumor cell proliferation but only at concentrations >100-fold higher than the concentrations that inhibit COX-1 activity. E-DMSS analogues may be useful probes of COX-1 biology in vivo and promising leads for COX-1-targeted therapeutic agents.