Selenium-Based Novel Epigenetic Regulators Offer Effective Chemotherapeutic Alternative with Wider Safety Margins in Experimental Colorectal Cancer.

Colorectal cancer (CRC) is a major cause of morbidity and mortality worldwide. Despite the critical involvement of epigenetic modifications in CRC, the studies on the chemotherapeutic efficacy of various epigenetic regulators remain limited. Considering the key roles of histone deacetylases (HDACs) in the regulation of diverse cellular processes, several HDAC inhibitors are implied as effective therapeutic strategies.

Imatinib exhibit synergistic pleiotropy in the prevention of colorectal cancer by suppressing proinflammatory, cell survival and angiogenic signaling.

Recent global incidences and mortality rates have placed colorectal cancer (CRC) at third and second positions, respectively, among both sexes of all ages. Resistance during chemotherapy is a big problem in the treatment and disease-free survival of CRC patients. Discovery of new anticancer drug(s) is a time taking process and therefore, invites studies for repurposing the known therapeutics.

Imatinib modulates pro-inflammatory microenvironment with angiostatic effects in experimental lung carcinogenesis.

Lung cancer has second highest rate of incidence and mortality around the world. Smoking cigarettes is the main stream cause of lung carcinogenesis along with other factors such as spontaneous mutations, inactivation of tumor suppressor genes. The present study was aimed to identify the mechanistic role of Imatinib in the chemoprevention of experimental lung carcinogenesis in rat model.

Chemoprevention of Colon Cancer through Inhibition of Angiogenesis and Induction of Apoptosis by Nonsteroidal Anti-Inflammatory Drugs.

Cancer cells require nourishment for the growth of the primary tumor mass and spread of the metastatic colony. These needs are fulfilled by tumor-associated neovasculature known as angiogenesis, which also favors the transition from hyperplasia to neoplasia, that is, from a state of cellular multiplication to uncontrolled proliferation. Therefore, targeting angiogenesis is profitable as a mechanism to inhibit tumor growth.

Cell cycle regulation and apoptotic cell death in experimental colon carcinogenesis: intervening with cyclooxygenase-2 inhibitors.

Relative imbalance in the pathways regulating cell cycle, cell proliferation, or cell death marks a prerequisite for neoplasm. C-phycocyanin, a biliprotein from Spirulina platensis and a selective COX-2 inhibitor along with piroxicam, a traditional nonsteroidal antiinflammatory drug was used to investigate the role of cell cycle regulatory proteins and proinflammatory transcription factor NFκB in 1,2-dimethylhydrazine dihydrochloride (DMH)-induced rat colon carcinogenesis. Cell cycle regulators [cyclin D1, cyclin E, cyclin dependent kinase 2 (CDK2), CDK4, and p53], NFκB (p65) pathway, and proliferating cell nuclear antigen (PCNA) were evaluated by gene and protein expression, whereas apoptosis was studied by terminal deoxynucleotidyl transferase dUTP nick end labeling and apoptotic bleb assay.

Upregulation of MAPK/Erk and PI3K/Akt pathways in ulcerative colitis-associated colon cancer.

An extracellular signal like a cytokine or chemokine, secreted in the inflammatory microenvironment can activate the mitogen activated protein kinase (MAPK) pathway by binding to a cytokine receptor tyrosine kinase, which further activates tyrosine kinases such as Janus Kinase-3 (Jak-3). This signal is transferred from Jak-3 to the DNA in the nucleus of the cell by a chain of kinases, ultimately activating extracellular receptor kinase (Erk/MAPK). The latter phosphorylates c-myc, an oncogene, which alters the levels and activities of many transcription factors leading to cell survival, proliferation and invasion.

The PI3K/Akt pathway in colitis associated colon cancer and its chemoprevention with celecoxib, a Cox-2 selective inhibitor.

Oncogenesis and angiogenesis are the two major pathways involved in tumorigenesis. Oncogenesis involves the PI3K/Akt and Wnt/β-catenin pathways, both of which are upregulated in several types of cancers. We established animal model of ulcerative colitis, colon cancer and colitis associated colon cancer by the incorporation of dextran sufate sodium (DSS) and dimethyl hydrazine (DMH), alone as well as in combination.

Targeting angiogenic pathway for chemoprevention of experimental colon cancer using C-phycocyanin as cyclooxygenase-2 inhibitor.

An angiogenic pathway was studied that involved stromal tissue degradation with matrix metalloproteinases (MMPs), vesicular endothelial growth factor-A (VEGF-A), and hypoxia inducible factor-1α (HIF-1α) mediated growth regulation in a complex interaction with chemokines, such as monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1β (MIP-1β). Gene and protein expression was studied with real-time PCR, Western immunoblot, and immunofluorescence. Morphological and histopathological analysis of tumor was done, as also the activity of MMPs and HIF-1α by gelatin zymography and ELISA.

Piroxicam and c-phycocyanin prevent colon carcinogenesis by inhibition of membrane fluidity and canonical Wnt/β-catenin signaling while up-regulating ligand dependent transcription factor PPARγ.

The colon cancer tissues from DMH treated rats exhibited higher membrane potential, fluidity and changed lipid order as examined by Merocyanine 540 and 1,6-diphenyl-1,3,5-hexatriene, respectively. A transition from gel to liquid crystalline state was observed by Laurdan fluorescence and also reduced fluorescence quenching of NBD-PE as contributed in the decreased membrane lipid phase separation. With piroxicam, a traditional NSAID and c-phycocyanin, a biliprotein from Spirulina platensis, these effects were normalized.

Anti-proliferative action of silibinin on human colon adenomatous cancer HT-29 cells.

Background: Silibinin a flavonoid from milk thistle (Silybum marianum) exhibit a variety of pharmacological actions, including anti-proliferative and apoptotic activities against various types of cancers in intact animals and cancer cell lines. In the present study, the effect of silibinin on human colon cancer HT-29 cells was studied.

Method: Incubations of cells with different silibinin concentrations (0.

Activation of NF-κB: bridging the gap between inflammation and cancer in colitis-mediated colon carcinogenesis.

Several studies have shown the anti-neoplastic effects of non-steroidal anti-inflammatory drugs (NSAIDs) on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis, but how these drugs act in case of inflammation-augmented tumorigenesis is still not clear. The present study therefore designs an animal model of colitis-associated colon cancer where 3% Dextran sufate sodium (DSS) is used to develop ulcerative colitis and DMH treatment leads to colon carcinogenesis as early as in six weeks. Clinical symptoms for ulcerative colitis were studied using Disease Activity Index (DAI) while myeloperoxidase assay marked the neutrophil infiltration in DSS and DMH treated groups.

Sulindac and Celecoxib regulate cell cycle progression by p53/p21 up regulation to induce apoptosis during initial stages of experimental colorectal cancer.

In the present study we have elaborated the putative mechanisms could be followed by the non-steroidal anti-inflammatory drugs (NSAIDs) viz. Sulindac and Celecoxib in the regulation of cell cycle checkpoints along with tumor suppressor proteins to achieve their chemopreventive effects in the initial stages of experimental colorectal cancer. Male Sprague-Dawley rats were administered with 1,2-dimethylhydrazine dihydrochloride (DMH) to produce early stages of colorectal carcinogenesis.

Role of cytokines and Jak3/Stat3 signaling in the 1,2-dimethylhydrazine dihydrochloride-induced rat model of colon carcinogenesis: early target in the anticancer strategy.

The molecular mechanisms by which colon cancer cells regulate the expression of various proinflammatory and anti-inflammatory cytokines and transcription factors resulting in tumor progression have not been well clarified. The present study thus explores the effect of cancer cell-derived cytokines and transcription factors on the chemoprevention of a rat model of early colon carcinogenesis. Elevated expression of proinflammatory cytokines [interleukin-1β (IL-1β), IL-2, interferon γ, and tumor necrosis factor-α] and the transcription factors [Janus kinase 3 (Jak3) and signal transducer and activator of transcription 3 (Stat3)] was found in the 1,2-dimethylhydrazine dihydrochloride (DMH) group; however, this elevated expression was reversed by the individual and combination treatment with piroxicam, a traditional nonsteroidal anti-inflammatory drug [inhibiting both cyclooxygenase-1 (COX-1) and COX-2] and c-phycocyanin, a cyanobacterium-derived biliprotein from Spirulina platensis (selective COX-2 inhibitor).

NSAIDs may regulate EGR-1-mediated induction of reactive oxygen species and non-steroidal anti-inflammatory drug-induced gene (NAG)-1 to initiate intrinsic pathway of apoptosis for the chemoprevention of colorectal cancer.

This study aims to investigate the unclear molecular relationship involved in the activation of intrinsic pathway of apoptosis and NSAID-activated gene-1 (NAG-1) induction as a putative target in NSAIDs-mediated chemoprevention of colorectal cancer. Male Sprague-Dawley rats were administered with a colon-specific pro-carcinogen, 1,2-dimethylhydrazine dihydrochloride to achieve the early stages of colorectal cancer. Histopathological examination was performed for the analysis of neoplastic lesions while flow cytometry was performed for the relative quantification of intracellular reactive oxygen species (ROS), differential mitochondrial membrane potential (MMP or ΔΨ(M)), and apoptotic events.

Angiostatic properties of sulindac and celecoxib in the experimentally induced inflammatory colorectal cancer.

Initiation of various cancers has been observed to be regulated via a prolonged inflammatory state in the tissues. However, molecular role of such a localized inflammation is not clear in the advanced stages of colorectal cancer. In this study, we have elaborated the role of various pro- and anti-inflammatory cytokines, transcription, and angiogenic factors in the progression of the 1,2-dimethylhydrazine dihydrochloride (DMH)-induced late phage colorectal cancer and also observed the chemopreventive role of the two non-steroidal anti-inflammatory drugs (NSAIDs), viz.

Role of cytokines in experimentally induced lung cancer and chemoprevention by COX-2 selective inhibitor, etoricoxib.

This study explored the role of pro- and anti-inflammatory cytokines in dimethyl benz(a)anthracene (DMBA)-induced lung cancer and its subsequent correction with a COX-2 inhibitory NSAID, etoricoxib. A single dose of DMBA (20 mg/kg body weight) in 0.9 % NaCl administered intratracheally was used to induce tumors in the rat lungs in 20 weeks.

Downregulation of NF-κB and PCNA in the regulatory pathways of apoptosis by cyclooxygenase-2 inhibitors in experimental lung cancer.

Non-steroidal anti-inflammatory drugs (NSAIDs) are emerging as novel chemopreventive agents against a variety of cancers owing to their capability in blocking the tumor development by cellular proliferation, angiogenesis and by promoting apoptosis. The present study further explored the comparative role of a traditional NSAID, indomethacin and a newly developed coxib, etoricoxib against 9,10-dimethylbenz(a)anthracene (DMBA)-induced lung carcinogenesis in rats. Morphological and histological analysis revealed the occurrence of tumors and lesions along with constricted alveolar spaces in the DMBA treated animals which were largely corrected both by indomethacin and etoricoxib.

Nuclear factor kappa B: a pro-inflammatory, transcription factor-mediated signalling pathway in lung carcinogenesis and its inhibition by nonsteroidal anti-inflammatory drugs.

9,10-Dimethyl benz(a)anthracene (DMBA), when injected intratracheally once at a dose of 20 mg/kg body weight, is found to induce lung cancer in rats. Two nonsteroidal anti-inflammatory drugs (NSAIDs), indomethacin and etoricoxib, are given orally daily as chemopreventive agents at a dose of 0.6 mg/kg body weight and 2 mg/kg body weight, respectively, along with DMBA.

PTEN regulates apoptotic cell death through PI3-K/Akt/GSK3β signaling pathway in DMH induced early colon carcinogenesis in rat.

Phosphatidylinositol 3-kinase (PI3-K) and Akt (protein kinase B), are both essential signaling molecules that are up-regulated in various cancers. Here, we examined the molecular mechanisms by which PI3-K and Akt expression are regulated by glycogen synthase kinase-3β (GSK-3β) and the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in the early stages of experimental colon carcinogenesis. 1,2-dimethylhydrazine (DMH) was utilized for the induction of colon cancer while piroxicam, a traditional non-steroidal anti-inflammatory drug and c-phycocyanin, a biliprotein from Spirulina platensis (cyanobacterium) as the chemopreventive agents.

Dolastatin 15, a mollusk linear peptide, and Celecoxib, a selective cyclooxygenase-2 inhibitor, prevent preneoplastic colonic lesions and induce apoptosis through inhibition of the regulatory transcription factor NF-κB and an inflammatory protein, iNOS.

The marine ecosystem is a unique and enormously rich source of natural products with potential chemopreventive applications in cancer. In the present study, we explored the chemopreventive role and the molecular mechanism of Dolastatin, a linear peptide from an Indian Ocean mollusk, and Celecoxib, a well-established cyclooxygenase-2 (COX-2) inhibitor in an individual as well as in a combination regimen in 1,2-dimethylhydrazine dihydrochloride (DMH)-induced colon carcinogenesis in a rat model. After a 6-week treatment with DMH, morphological analysis revealed a marked occurrence of preneoplastic features in the colonic mucosa, whereas histologically well-characterized dysplasia and hyperplasia were observed in DMH-treated animals.

Chemopreventive effects of NSAIDs as inhibitors of cyclooxygenase-2 and inducers of apoptosis in experimental lung carcinogenesis.

Roles of cyclooxygenase (COX) enzyme and intrinsic pathway of apoptosis have been explored for the chemopreventive effects of non-steroidal anti-inflammatory drugs (NSAIDs) on 9,10-dimethyl benz(a)anthracene (DMBA)-induced lung cancer in rat model. 16 weeks after the administration of DMBA, morphological analysis revealed the occurrences of tumours and lesions, which were regressed considerably with the co-administration of indomethacin and etoricoxib, the two NSAIDs under investigation. DMBA group was marked by hyperplasia and dysplasia as observed by histological examination, and these features were corrected to a large extent by the two NSAIDs.

Role of Sulindac and Celecoxib in the regulation of angiogenesis during the early neoplasm of colon: exploring PI3-K/PTEN/Akt pathway to the canonical Wnt/β-catenin signaling.

Angiogenesis refers to the generation of new blood vasculature from the nearby pre-existing one and is regulated by a balance between the pro- and anti-angiogenic factors. During carcinogenesis, pro-angiogenic factors dominate and initialize the growth of new blood capillaries to provide nutrition, growth factors and overcome hypoxia inside the tumor microenvironment. In the present study, we have observed the role of Phosphatidylinositol-3-kinase (PI3-K)/Phophatase and tensin homolog deleted on chromosome ten (PTEN)/Akt (Protein kinase B) pathway and canonical Wnt/β-catenin downstream signaling in the regulation of various pro-angiogenic molecules including the vascular endocrine growth factor-A (VEGF-A), matix metalloproteinases (MMPs), inducible nitric oxide synthase (iNOS) and chemokines for the progression of experimental colorectal cancer with 1,2-dimethylhydrazine dihydrochloride (DMH) and anti-angiogenic effects of two non-steroidal anti-inflammatory drugs (NSAIDs) viz.

Role of Sulindac and Celecoxib in chemoprevention of colorectal cancer via intrinsic pathway of apoptosis: exploring NHE-1, intracellular calcium homeostasis and Calpain 9.

Non-steroidal anti-inflammatory drugs (NSAIDs) have become promising agents for the chemoprevention of colorectal cancer presumably by inducing apoptosis. However, the role of NSAIDs in the regulation of NHE-1, intracellular calcium [Ca(2+)](i) homeostasis and Calpain 9 signaling pathway seems unclear. Male Sprague-Dawley rats were used as model for experimental colorectal cancer.

Piroxicam and C-phycocyanin mediated apoptosis in 1,2-dimethylhydrazine dihydrochloride induced colon carcinogenesis: exploring the mitochondrial pathway.

Apoptosis is a synchronized procedure of cell death that is regulated by caspases and proapoptotic proteins. During apoptosis, translocation of cytochrome c, an electron carrier, from mitochondria into the cytosol is regulated by Bcl-2 family members. Cytochrome c in association with an apoptotic protease activating factor (Apaf), a proapoptotic protein essential for cell differentiation and procaspase-9 form the apoptosome complex, which consecutively activates effector caspase, caspase-3, and coordinate the implementation of apoptosis.

Chemoprevention of DMH-induced rat colon carcinoma initiation by combination administration of piroxicam and C-phycocyanin.

Cancer research illustrated that combinatorial studies can provide significant improvement in safety and effectiveness over the monotherapy regimens. A combination of two drugs may restrain precancerous colon polyps, opening a new possible opportunity for chemoprevention of colon cancer. In this context, chemopreventive efficacy of a combination regimen of C-phycocyanin, a biliprotein present in Spirulina platensis, a cyanobacterium, which is a selective cycloxygenase-2 (COX-2) inhibitor and piroxicam, a traditional non-steroidal anti-inflammatory drug was considered in 1,2 dimethylhyadrazine (DMH)-induced colon carcinogenesis in rats.