Sulindac induces apoptosis and protects against colon carcinoma in mice

Combination Chemotherapy of Multidrug-resistant Early-stage Colon Cancer: Determining Optimal Dose Schedules by High-performance Computer Simulation

The goal of this project was to utilize mechanistic simulation to demonstrate a methodology that could determine drug combination dose schedules and dose intensities that would be most effective in eliminating multidrug resistant cancer cells in early-stage colon cancer. An agent-based model of cell dynamics in human colon crypts was calibrated using measurements of human biopsy specimens. Mutant cancer cells were simulated as cells that were resistant to each of two drugs when the drugs were used separately. The drugs, 5-flurouracil and sulindac, have different mechanisms of action. An artificial neural network was used to generate nearly two hundred thousand two-drug dose schedules. A high-performance computer simulated each dose schedule as a in silico clinical trial and evaluated each dose schedule for its efficiency to cure (eliminate) multidrug resistant cancer cells and its toxicity to the host, as indicated by continued crypt function. Among the dose schedules that were generated, 2430 dose schedules were found to cure all multidrug resistant mutants in each of the 50 simulated trials and retained colon crypt function. One dose schedule was optimal; it eliminated multidrug resistant cancer cells with the minimum toxicity and had a time schedule that would be practical for implementation in the clinic. These results demonstrate a procedure to identify which combination drug dose schedules could be most effective in eliminating drug resistant cancer cells. This was accomplished using a calibrated agent-based model of a human tissue, and a high-performance computer simulation of clinical trials.

Hedgehog Signaling: Linking Embryonic Lung Development and Asthmatic Airway Remodeling

The development of the embryonic lung demands complex endodermal–mesodermal interactions, which are regulated by a variety of signaling proteins. Hedgehog (Hh) signaling is vital for lung development. It plays a key regulatory role during several morphogenic mechanisms, such as cell growth, differentiation, migration, and persistence of cells. On the other hand, abnormal expression or loss of regulation of Hh signaling leads to airway asthmatic remodeling, which is characterized by cellular matrix modification in the respiratory system, goblet cell hyperplasia, deposition of collagen, epithelial cell apoptosis, proliferation, and activation of fibroblasts. Hh also targets some of the pathogens and seems to have a significant function in tissue repairment and immune-related disorders. Similarly, aberrant Hh signaling expression is critically associated with the etiology of a variety of other airway lung diseases, mainly, bronchial or tissue fibrosis, lung cancer, and pulmonary arterial hypertension, suggesting that controlled regulation of Hh signaling is crucial to retain healthy lung functioning. Moreover, shreds of evidence imply that the Hh signaling pathway links to lung organogenesis and asthmatic airway remodeling. Here, we compiled all up-to-date investigations linked with the role of Hh signaling in the development of lungs as well as the attribution of Hh signaling in impairment of lung expansion, airway remodeling, and immune response. In addition, we included all current investigational and therapeutic approaches to treat airway asthmatic remodeling and immune system pathway diseases.

NSAIDs: Old Acquaintance in the Pipeline for Cancer Treatment and Prevention─Structural Modulation, Mechanisms of Action, and Bright Future

The limitations of current chemotherapeutic drugs are still a major issue in cancer treatment. Thus, targeted multimodal therapeutic approaches need to be strategically developed to successfully control tumor growth and prevent metastatic burden. Inflammation has long been recognized as a hallmark of cancer and plays a key role in the tumorigenesis and progression of the disease. Several epidemiological, clinical, and preclinical studies have shown that traditional nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit anticancer activities. This Perspective reports the most recent outcomes for the treatment and prevention of different types of cancers for several NSAIDs alone or in combination with current chemotherapeutic drugs. Furthermore, an extensive review of the most promising structural modifications is reported, such as phospho, H₂S, and NO releasing-, selenium-, metal complex-, and natural product-NSAIDs, among others. We also provide a perspective about the new strategies used to obtain more efficient NSAID- or NSAID derivative- formulations for targeted delivery.

Sulindac and vitamin D3 synergically inhibit proliferation of MCF-7 breast cancer cell through AMPK/Akt/β-catenin axis in vitro

Breast cancer is associated with a high rate of recurrence, resistance therapy and mortality worldwide. We aimed at investigating the inhibitory effects of Sulindac and vitamin D3 (VD) on MCF-7 human breast cancer cells. MCF-7 cells were cultured with different concentrations of Sulindac and VD over a period of 24, 48 and 72 hours for cell viability and IC50 experiments. Hochst staining was used to evaluate apoptosis, whereas quantitative PCR (qPCR) was performed to measure mRNA levels of BCL-2 and BAX genes. Immunofluorescence staining was used to monitor intracellular β-catenin expression. The protein levels of AKT, AMPK and P65 were measured by western blotting. The result showed that cell viability decreased in treated cells dose/time dependently (P < .05). Hochst staining showed an increase in fragmented nuclei in treated cells. The expression of BCL-2 and BAX genes decreased and increased in treated cells, respectively (P < .05). Immunofluorescence staining indicated that the expression of β-catenin significantly reduced in treated cells. The AKT-1/p-Akt-1 and AMPK/p-AMPK ratio increased in treated cells (P < .05), but the P65/p-P65 ratio did not change significantly (P > .05). Our results indicated that the combination of Sulindac and VD has a growth-inhibiting effect on MCF-7 cells through AMPK/Akt/β-catenin axis.

Prevention of Colon Cancer Recurrence From Minimal Residual Disease: Computer Optimized Dose Schedules of Intermittent Apoptotic Adjuvant Therapy

PURPOSE

Adjuvant chemotherapy is used after surgery for stages II and III colorectal cancer to reduce recurrence. Nevertheless, recurrence may occur years later with the emergence of initially undetected minimal residual disease (MRD). Attempts to reduce recurrence by increasing the dose intensity and increasing the time of adjuvant therapy have been limited by the adverse effects of the recommended cytotoxic agents. The goals of this study were to suggest an alternative to the recommended cytotoxic agents and to determine optimal adjuvant therapy dose schedules that would reduce the percentage of recurrence at 5 years while retaining colon crypt function.

METHODS

A total of 84,400 dose schedules with different duration, interval between doses, and intensity of treatment were simulated with a high-performance computer. Simulated treatments used the drug sulindac, which had previously been used in primary prevention. With appropriate dose schedules, it can induce apoptosis at the crypt lumen surface while retaining crypt function. We used a computer model of cell dynamics in colon crypts that had been calibrated with measurements of human biopsy specimens. Proliferating mutant cells were assumed to emerge from MRD within crypts. Simulated outcomes included the recurrence percentage at 5 years and the retention of crypt function.

RESULTS

Optimal dose schedules were determined for adjuvant treatment of MRD that reduced the percentage of recurrence at 5 years of stages I, II, and III colon cancer to zero.

CONCLUSION

A new adjuvant therapy for colon cancer based upon optimum dose schedules of intermittent apoptotic treatment may prevent the recurrence of colon cancer from MRD and avoid the adverse effects of cytotoxic treatments.

In Vivo Antineoplastic Effects of the NSAID Sulindac in an Oral Carcinogenesis Model

The antineoplastic properties of the NSAID sulindac have long been studied. The purpose of this study was to explore sulindac's in vivo effects on oral squamous cell carcinoma (SCC) oncogenesis using the hamster cheek pouch oral carcinogenesis model (HOCM). Thirty Syrian golden hamsters were divided into three experimental and two control groups (n = 6 each). The animals' right buccal pouches were treated with carcinogen for 9 weeks in one experimental and one control group and for 14 weeks in all other three groups. The animals of two experimental groups received sulindac from the 1st week and those of the third experimental group from the 10th week. After the end of carcinogenesis, treated buccal pouches were removed and examined. In animals treated with carcinogen for 14 weeks, development of oral SCC and tumor volume were significantly lower in animals that received sulindac from the first week of the experiment. Oral SCC developing in animals that received sulindac were more frequently well differentiated compared with the control group. In animals treated with carcinogen for 9 weeks, the animals that received sulindac developed lower grade of epithelial dysplasia. Proliferation index Ki-67 and positivity for the antiapoptotic molecule survivin were lower in the animals that received sulindac. Treatment with sulindac appears to delays the progression of oral premalignant lesions to oral SCC in the HOCM, also resulting in smaller and better differentiated tumors. These in vivo antineoplastic effects may be related to sulindac's ability to decrease cell proliferation and to prevent survivin expression.

Sulindac modulates secreted protein expression from LIM1215 colon carcinoma cells prior to apoptosis

Colorectal cancer (CRC) is a major cause of mortality in Western populations. Growing evidence from human and rodent studies indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) cause regression of existing colon tumors and act as effective chemopreventive agents in sporadic colon tumor formation. Although much is known about the action of the NSAID sulindac, especially its role in inducing apoptosis, mechanisms underlying these effects is poorly understood. In previous secretome-based proteomic studies using 2D-DIGE/MS and cytokine arrays we identified over 150 proteins released from the CRC cell line LIM1215 whose expression levels were dysregulated by treatment with 1mM sulindac over 16h; many of these proteins are implicated in molecular and cellular functions such as cell proliferation, differentiation, adhesion, angiogenesis and apoptosis (Ji et al., Proteomics Clin. Appl. 2009, 3, 433-451). We have extended these studies and describe here an improved protein/peptide separation strategy that facilitated the identification of 987 proteins and peptides released from LIM1215 cells following 1mM sulindac treatment for 8h preceding the onset of apoptosis. This peptidome separation strategy involved fractional centrifugal ultrafiltration of concentrated cell culture media (CM) using nominal molecular weight membrane filters (NMWL 30K, 3K and 1K). Proteins isolated in the >30K and 3-30K fractions were electrophoretically separated by SDS-PAGE and endogenous peptides in the 1-3K membrane filter were fractioned by RP-HPLC; isolated proteins and peptides were identified by nanoLC-MS-MS. Collectively, our data show that LIM1215 cells treated with 1mM sulindac for 8h secrete decreased levels of proteins associated with extracellular matrix remodeling (e.g., collagens, perlecan, syndecans, filamins, dyneins, metalloproteinases and endopeptidases), cell adhesion (e.g., cadherins, integrins, laminins) and mucosal maintenance (e.g., glycoprotein 340 and mucins 5AC, 6, and 13). A salient finding of this study was the increased proteolysis of cell surface proteins following treatment with sulindac for 8h (40% higher than from untreated LIM1215 cells); several of these endogenous peptides contained C-terminal amino acids from transmembrane domains indicative of regulated intramembrane proteolysis (RIP). Taken together these results indicate that during the early-stage onset of sulindac-induced apoptosis (evidenced by increased annexin V binding, dephosphorylation of focal adhesion kinase (FAK), and cleavage of caspase-3), 1mM sulindac treatment of LIM1215 cells results in decreased expression of secreted proteins implicated in ECM remodeling, mucosal maintenance and cell-cell-adhesion. This article is part of a Special Issue entitled: An Updated Secretome.

Evaluation of antiulcer activity of indole-3-carbinol and/or omeprazole on aspirin-induced gastric ulcer in rats

The present work is an attempt to elucidate the antiulcer activity of indole-3-carbinol (I3C), which is one of the anticarcinogenic phytochemicals found in the vegetables of Cruciferae family such as broccoli and cauliflower, alone or in combination with omeprazole (OMP), a proton pump inhibitor, to diminish the effects of induced acute gastric ulcer by aspirin (ASA) in male albino rats. A total of 48 adult male albino rats were used in the present study. Animals were divided into eight experimental groups (six animals each group). They were given different experimental inductions of ASA at a dose of 500 mg/kg/body weight, OMP at a dose of 20 mg/kg/body weight and I3C at a dose of 20 mg/kg/body weight either alone or in combination with each other orally for a duration of 7 days. Inner stomach features, ulcer index, pH activity, body weight, stomach weight, hematological investigations, serum total protein albumin and reduced glutathione activity  were investigated in addition to the histological, histochemical and immunohistochemical stain of cyclooxygenase-2 to the stomach tissue of normal control, ulcerated and treated ulcerated rats. The results of this study revealed that oral administration of ASA to rats produced the expected characteristic mucosal lesions. OMP accelerated ulcer healing but the administration of I3C either alone or in combination with OMP to ASA-ulcerated rats produced a profound protection to the gastric mucosa from injury induced by ASA. Our results suggested that administration of antiulcer natural substances such as I3C in combination with the perused treatment such as OMP is a very important initiative in the development of new strategies in ulcer healing.

Molecular pathways underlying IBD-associated colorectal neoplasia: therapeutic implications

Chronic inflammatory diseases, depending upon the duration and severity, are frequently associated with an increased risk of developing cancer. A classic paradigm is the enhanced risk of colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD). Carcinogenesis is a multifactorial process that involves accumulation of genetic defects, protein modification, and cell-matrix interaction. In this review, we discuss aspects of chronic inflammation in IBD that influence the development of CRC and highlight the key molecular mediators involved in this process. Also, we identify potential targets that could facilitate earlier detection of dysplasia. The targeted manipulation of specific molecules or pathways could provide opportunities for the development of therapeutic and chemopreventive interventions, which may prove effective in arresting the progression of colitis-associated cancer (CAC), with clinical implications.

Inhibitory effect of silibinin against azoxymethane-induced colon tumorigenesis in A/J mice

PURPOSE

Colorectal cancer is the second leading cause of cancer-associated deaths, which suggests that more effort is needed to prevent/control this disease. Herein, for the first time, we investigate in vivo the efficacy of silibinin against azoxymethane-induced colon tumorigenesis in A/J mice.

EXPERIMENTAL DESIGN

Five-week-old male mice were gavaged with vehicle or silibinin (250 and 750 mg/kg) for 25 weeks starting 2 weeks before initiation with azoxymethane (pretreatment regime) or for 16 weeks starting 2 weeks after the last azoxymethane injection (posttreatment regime). The mice were then sacrificed, and colon tissues were examined for tumor multiplicity and size, and molecular markers for proliferation, apoptosis, inflammation, and angiogenesis.

RESULTS

Silibinin feeding showed a dose-dependent decrease in azoxymethane-induced colon tumorigenesis with stronger efficacy in pretreatment versus posttreatment regimen. Mechanistic studies in tissue samples showed that silibinin inhibits cell proliferation as evident by a decrease (P < 0.001) in proliferating cell nuclear antigen and cyclin D1, and increased Cip1/p21 levels. Silibinin also decreased (P < 0.001) the levels of inducible nitric oxide synthase, cyclooxygenase-2, and vascular endothelial growth factor, suggesting its anti-inflammatory and antiangiogenic potential in this model. Further, silibinin increased cleaved caspase-3 and poly(ADP-ribose) polymerase levels, indicating its apoptotic effect. In other studies, colonic mucosa and tumors expressed high levels of β-catenin, insulin-like growth factor-1 receptorβ, phospho Glycogen synthase kinase-3β, and phospho protein kinase B/pAkt proteins in azoxymethane-treated mice, which were strongly lowered (P < 0.001) by silibinin treatment. Moreover, azoxymethane reduced insulin-like growth factor binding protein-3 protein level, which was enhanced by silibinin.

CONCLUSIONS

Silibinin targets β-catenin and IGF-1Rβ pathways for its chemopreventive efficacy against azoxymethane-induced colon carcinogenesis in A/J mice. Overall, these results support the translational potential of silibinin in colorectal cancer chemoprevention.

Wnt signaling pathway and lung disease

The Wnt pathway plays an important role in development and in regulating adult stem cell systems. A variety of cellular processes is mediated by Wnt signaling, which includes cellular proliferation, differentiation, survival, apoptosis, and cell motility. Loss of regulation of these pathways can lead to tumorigenesis, and the Wnt pathway has been implicated in the development of several types of cancers, including colon, lung, leukemia, breast, thyroid, and prostate. The Wnt pathway has also been associated with other lung diseases such as interstitial lung disease (ILD) and asthma. Our increasing understanding of the Wnt pathway offers great hope that new molecular-based screening tests and pharmaceutical agents that selectively target this pathway will be developed to diagnose and treat these diseases in the future.

Intrinsic resistance to apoptosis of colon epithelial cells is a potential determining factor in the susceptibility of the A/J mouse strain to dimethylhydrazine-induced colon tumorigenesis

Alterations in the delicate balance between cell proliferation and cell death disrupt colon homeostasis and serve as determining factors in colon tumorigenesis. The two mouse strains, AKR/J (resistant) and A/J (susceptible), have been widely used as models for dimethylhydrazine-induced colon tumorigenesis. This study examined whether the differential susceptibilities of the two mouse strains to the tumorigenic effect of dimethylhydrazine were associated with intrinsic differences in the apoptotic machinery of the colon epithelial cells. While acute exposure to dimethylhydrazine caused massive apoptosis of colon epithelial cells in AKR/J mice, the effect was considerably less in A/J mice. Apoptosis in AKR/J mice occurred not only in the luminal side of the mucosa but also deep in the colonic crypts. In addition, this apoptosis appeared to involve caspase-3. The increased sensitivity of AKR/J to dimethylhydrazine was associated with a persistent expression of tumor necrosis factor (TNF) but not of its receptors. After establishing a new method for isolating primary colon epithelial cells, we determined that cells derived from A/J mice were substantially more resistant to apoptosis in response to dimethylhydrazine or to a combination of TNF, cyclohexamide, and butyrate compared to cells from AKR/J mice. These results strongly suggest that a higher intrinsic resistance to apoptosis of colon epithelial cells may be an important determinant of predisposition to colon tumorigenesis in the A/J mouse strain.

Sulindac induces apoptosis and inhibits tumor growth in vivo in head and neck squamous cell carcinoma

Sulindac has antineoplastic effects on various cancer cell lines; consequently, we assessed sulindac's effects on laryngeal squamous cell carcinoma (SCC) cells in vitro and in vivo. In vitro, SCC (HEP-2) cells treated with various cyclooxygenase inhibitors or transfected with constitutively active signal transducer and activator of transcription 3 (Stat3) or survivin vectors were analyzed using Western blot analysis, annexin V assay, and cell proliferation assay. In parallel, nude mice injected subcutaneously with HEP-2 cells were either treated intraperitoneally with sulindac or left untreated, and analyzed for tumor weight, survivin expression, and tyrosine-phosphorylated Stat3 expression. In vitro studies confirmed the selective antiproliferative and proapoptotic effects of sulindac, which also downregulated Stat3 and survivin protein expression. Stat3 or survivin forced expression partially rescued the antiproliferative effects of sulindac. In vivo studies showed significant repression of HEP-2 xenograft growth in sulindactreated mice versus controls, with near-complete resolution at 10 days. Additionally, tumor specimens treated with sulindac showed downregulation of phosphorylated tyrosine-705 Stat3 and survivin expression. Taken together, our data suggest, for the first time, a specific inhibitory effect of sulindac on tumor growth and survivin expression in laryngeal cancer, both in vitro and in vivo, in a Stat3-dependent manner, suggesting a novel therapeutic approach to head and neck cancer.

Characteristic expression of γ-aminobutyric acid and glutamic acid decarboxylase in epithelial cells of rat descending colon

AIM: To detect the expression of γ-aminobutyric acid (GABA) and glutamate decarboxylases (GADs) in the epithelial growth zones of rat descending colon, and to investigate their relations with cell differentiation and proliferation.

METHODS: Immunocytochemical expression of GABA and GADs in the epithelial cells of rat descending colon was investigated by immunofluorescent staining and confocal laser scanning techniques, and the goblet cells were further revealed by wheat-germ agglutinin (WGA) histochemistry. GAD65 and GAD67 mRNAS were also detected by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. Furthermore, evaluation of cell kinetics in colonic epithelia was conducted by [³H]-thymidine autoradiography.

RESULTS: Immunoreactive GABA and GAD65 were distributed in the upper third of the crypts and at the luminal surface in the rat descending colon. Strong staining for GABA and GAD65 was localized mainly in the cytoplasm of epithelial cells near the neck of the crypts and along the luminal surface. Immunoreactivity of GAD67, however, was localized only on the luminal surface. In addition, GABA and GAD65 were detected at lamina propria in clonic mucosa. No staining for GABA or GADs was found in goblet cells. GAD65 and GAD67 mRNAs were both identified in the homogenates of rat descending colon, and the epithelium showed stronger hybridization signal for GAD65 mRNA than that for GAD67. Meanwhile, [³H]-thymidine labeled cells were found in the lower two-thirds of the crypts.

CONCLUSION: The expression of GABA and GADs in the maturation and function zones suggests that GABA might be involved in the differentiation and proliferation of the colonic epithelial cells.