NANOPARTICLES AND COLORECTAL CANCER: CAN THE USE OF METAL NANOPARTICLE COMPOSITIONS AFFECT OXIDATIVE STRESS MARKERS AND COLON HISTOLOGICAL CHANGES UNDER DMH-INDUCED CARCINOGENESIS.

Colorectal cancer (CRC) - a significant global health challenge. Exploring biological markers of oxidative stress is crucial, as they can play an essential role in initiating the transition from an organ's "healthy state" to a "malignant injury." There is substantial promise in investigating the level of 8-isoprostane (8-isoPGF2α) as a novel and dependable marker of oxidative stress. This paper presents that 8-isoprostane levels have been linked to the development of severe structural changes in the colon wall, accompanied by endogenic intoxication syndrome. The obtained results prove the strong connection between oxidative stress and carcinogenesis progression. Our research further illustrates the favorable and potentially beneficial impact of the Au/Ag/Fe NPs composition, which can find utility in a diverse range of contemporary applications.

Panx1 knockout promotes preneoplastic aberrant crypt foci development in a chemically induced model of mouse colon carcinogenesis.

Colorectal cancer, which is the third leading cause of cancer-related deaths worldwide, is a multistep disease, featuring preneoplastic aberrant crypt foci (ACF) as the early morphological manifestation. The roles of hemichannel-forming transmembrane Pannexin 1 (Panx1) protein have not been investigated in the context of colon carcinogenesis yet, although it has contrasting roles in other cancer types. Thus, this study was conducted to examine the effects of Panx1 knockout (Panx1-/- ) on the early events of chemically induced colon carcinogenesis in mouse. Wild type (WT) and Panx1-/- female C57BL6J mice were submitted to a chemically induced model of colon carcinogenesis by receiving six intraperitoneal administrations of 1,2-dimethylhydrazine (DMH) carcinogen. Animals were euthanized 8 h (week 7) or 30 weeks (week 37) after the last DMH administration in order to evaluate sub-acute colon toxicity outcomes or the burden of ACF, respectively. At week 7, Panx1 genetic ablation increased DMH-induced genotoxicity in peripheral blood cells, malondialdehyde levels in the colon, and apoptosis (cleaved caspase-3) in colonic crypts. Of note, at week 37, Panx1-/- animals showed an increase in aberrant crypts (AC), ACF mean number, and ACF multiplicity (AC per ACF) by 56%, 57% and 20%, respectively. In essence, our findings indicate that Panx1 genetic ablation promotes preneoplastic ACF development during chemically induced mouse colon carcinogenesis, and a protective role of Panx1 is postulated.

Long-term 1,2-dimethylhydrazine triggers pathological remodeling of colon mucosa through repression of sestrin2, nuclear factor (erythroid-derived 2)-like 2, and sirtuin4 stimulating mitochondrial stress and metabolic reprogramming.

1,2-Dimethylhydrazine (DMH) is a plant toxicant that enters the food web through the diet. It is biotransformed into azoxymethane, a colon carcinogen, during the first hepatic passage. In mice, this study assessed the role of glutamate dehydrogenase (GDH), a key glutaminolysis enzyme in DMH-induced colorectal cancer (CRC). Colon samples were taken from mice given 6 or 15 weekly doses of 20 mg/kg DMH and serially sacrificed. Repeated DMH doses induced early aberrant crypt foci that evolved into irreversible adenocarcinomas over 24 weeks, along with an increase in GDH and lactate dehydrogenase activities (+ 122%, + 238%, P < 0.001), indicating a switch to aerobic glycolysis and glutaminolysis. Transcriptional downregulation of the endogenous GDH inhibitor, sirtuin4, and two redox regulators, mitochondrial sestrin2 and nuclear factor (erythroid derivative 2)-like 2 (- 26% and - 22%, P < 0, 05; and - 30%, P < 0.01), exacerbated mitochondrial stress by boosting mitochondrial superoxide dismutase activity (+ 240% (P < 0.001) while depressing catalase activity and GSH levels (- 57% and - 60%, P < 0.001). In vitro, allosteric GDH inhibition by 50 µM epigallocatechin gallate decreased human carcinoma (HCT-116) cells' viability, clonogenicity, and migration (- 43% and - 57%, P < 0.001, 41%, P < 0.05), while stimulating ROS release (+ 57%, P < 0.001). Dimethylfumarate (DMF), a linear electrophile and mitochondrial fumarate analog, rebalanced ROS levels (- 34%, P < 0.05) and improved GDH activity, cell viability, and tumorogenic capacity (+ 20%, 20%, P < 0.001; and 33%, P < 0.05). Thus, the pathological remodeling of colon mucosa is supported by metabolic reprogramming bypassing uncoupled mitochondria. DMF highlights the critical role of electrophile response elements in modulating redox mithormesis and redox homeostasis during CRC.

EFFECT OF DRY EXTRACT FROM REISHI MUSHROOMS ON THE STATE OF ANTIOXIDANT SYSTEM IN RATS WITH DMH-INDUCED COLON CARCINOGENESIS.

OBJECTIVE: The aim: To study pro- and antioxidant systems indicators in rats with chemically induced colon carcinogenesis on the background of the reishi mushrooms dry extract use. PATIENTS AND METHODS: Materials and methods: The study was performed on 120 white male rats. Chronic oncogenic intoxication was modeled by administering 1,2-dimethyl¬hydrazine (DMH) hydrochloride for 30 weeks (1 time per week). A dry extract from the reishi mushrooms was administered intragastrically daily at a dose of 100 mg/kg of the animal's body weight. Blood and liver samples were taken for research monthly. The state of the pro- and antioxidant systems was studied by the content of oxidative modification of proteins products, superoxide dismutase and catalase activity, contents of reduced glutathione and ceruloplasmin. RESULTS: Results: An increase in the activity of free radical oxidation processes after DMH-induced colon carcinogenesis in rats is evidenced by a decrease in the super-oxide dismutase activity, catalase activity, content of reduced glutathione, an increase in the content of ceruloplasmin and products of oxidative modification of proteins in the blood serum and liver of animals. The effectiveness of the dry extract of reishi mushrooms and its positive effect on the state of pro- and antioxidant systems was experimentally proved. CONCLUSION: Conclusions: The use of the dry extract of reishi mushrooms under conditions of DMH-induced colon carcinogenesis in rats led to normalization of the anti¬oxidant protection system state and the reduction of oxidative stress.

The Antitumor Activity of Ginger against Colorectal Cancer Induced by Dimethylhydrazine in Rats.

BACKGROUND: Bowl or colorectal cancer (CRC) is the third most common type of cancer with about two million new cases every year. CRC is the second leading cause of cancer related mortalities. OBJECTIVE: The study aims to evaluate the anticancer activity of ethanolic Ginger Extract (GE) in HCT-116 colon cells and colorectal tumors induced by dimethylhydrazine (DMH). METHODS: The antiproliferative activity was measured by MTT assay and the gene expression was assessed by q-RTPCR. For the antitumor study, rats were divided into five groups in random; control, group two was orally treated with 300 mg/kg of GE for 21 weeks, group three was s.c. injected with DMH (20 mg/kg) for 9 weeks, and groups four and five were treated with DMH and then treated with cisplatin (2.5 mg/kg, i.p) or GE, respectively, for 21 weeks. RESULTS: GE had a significant antiproliferative activity with IC50~ 12.5 µg/ml. GE induced both extrinsic and intrinsic apoptotic pathways. GE induced the expression of FasL, TRAIL, p53, and caspase-8 and downregulated Bcl-2 and survivin genes. Treatment of rats with DMH resulted in 100% tumor incidence and 2.3 tumors/rat. DMH significantly elevated the serum ALT, urea, and creatinine and significantly decreased the body weight gain. DMH also caused significant reductions in the hepatic GSH level, and the activities of catalase, SOD, GST, and GR in the liver as well as the renal GSH content and γ-GT activity. The colon from rats insulted with DMH showed adenomatous polyps with polymorphism and mitosis. The mucosa and submucosa were infested with inflammatory cells while serosa and muscularis were devoid from these cells. However, the muscularis was infiltrated with cystic formation, anaplastic changes, and hemorrhage. GE was able to alleviate all the previous deleterious effects of DMH and it was superior to cisplatin in its ameliorative effects. It did so without eliciting hepatotoxicity or nephrotoxicity which were shown in the group treated with DMH and cisplatin. CONCLUSION: This study proved that the antitumor activity of GE against the DMH induced-CRC is superior to cisplatin. GE was also safer than cisplatin and did not elicit hepatotoxicity or nephrotoxicity. GE induced apoptosis and has carcinostatic activity.

Effect of Hesperidin against Induced Colon Cancer in Rats: Impact of Smad4 and Activin A Signaling Pathway.

SCOPE: To evaluate the chemopreventive efficacy of hesperidin (Hsd) in 1,2-dimethylhydrazine (DMH)-induced colorectal cancer (CRC) and demonstrate its role in mothers against decapentaplegic homolog 4(Smad4) and activin A signaling pathways. METHODS AND RESULTS: A CRC rat model was established by DMH exposure, and the animals were randomly divided into five groups: Control group, Hsd, DMH, DMH + Hsd, and DMH followed by Hsd. The resected colon was subjected to macroscopic, microscopic, molecular, histopathological, and immunohistochemical examination. Activin A, Smad4, malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), and superoxide dismutase (SOD) levels in tissues were also measured. The DMH group exhibited a significant increase in the gene and protein expression of activin A as well as MDA and NO levels in tissues. There was a significant reduction in the gene and protein expression of Smad4 as well as GSH and SOD levels in tissues. Administration of Hsd significantly upregulated Smad4 and activin A gene expressions in both the DMH + Hsd and DMH followed by Hsd groups. Moreover, Hsd improved the antioxidant status of the former two groups. CONCLUSION: This study demonstrated the chemopreventive effect of Hsd against CRC by modulating Smad4 and activin A signaling in vivo. Further studies are needed to demonstrate its clinical value and explore its possible role in advanced malignancy.

Chronic stress decreases ornithine decarboxylase expression and protects against 1,2-dimethylhydrazine-induced colon carcinogenesis.

Biological response to stress depends on the type, timing, and severity of the stressor. Acute stressful environments may positively activate molecular and cellular mechanisms to favor adaptation; however, chronic stress is often associated with detrimental health effects. Colon cancer (CC) is one of the leading causes of death associated with cancer and has been mentioned as a stress-related disease. In the present work, the effect of chronic stress on the initial phase of CC was evaluated, and special emphasis was placed on ornithine decarboxylase (ODC) expression and polyamines for their role in hyperproliferative diseases. BALB/c mice (n = 5/group) were administered the pro-carcinogen 1,2-dimethylhydrazine (DMH) for 8 weeks (20 mg/kg body weight/week) to induce colon carcinogenesis, and then exposed for 4 weeks to two physical stressors: restraint and forced-swimming. Distal colon inflammatory lesions and histomorphological changes were evaluated by hematoxylin-eosin staining; plasma corticosterone levels, colon ODC expression, and urinary polyamines were determined by competitive ELISA, RT-qPCR, Western Blot, and HPLC, respectively. The short-term exposure to DMH triggered colon inflammation, initiated colon carcinogenesis and increased ODC expression; meanwhile, the exposure to chronic stress activated the hypothalamic-pituitary-adrenal (HPA) axis, elicited the production of plasmatic corticosterone, and decreased ODC expression. The exposure of DMH-treated mice to chronic stress counteracted the inflammatory effect of DMH and maintained ODC homeostasis. In early phase of carcinogenesis, the exposure of DMH-treated mice to chronic stress had a positive effect against colon inflammation and maintained ODC homeostasis. The cross-talk between corticosterone, ODC expression, and inflammation in a tumor environment is discussed.

Effects of fucoidan on gut flora and tumor prevention in 1,2-dimethylhydrazine-induced colorectal carcinogenesis.

Colorectal cancer (CRC) is one of the major malignancies in humans. This study was designed to evaluate the effects of fucoidan on gut flora and tumor prevention in 1,2-dimethylhydrazine-induced colorectal carcinogenesis in rats. We found that dietary fucoidan treatment decreased the tumor incidence and mean tumor weight and increased cell apoptosis. Fucoidan treatment decreased the expression of ß-catenin C-Myc, CyclinD1 and Survivin, while the Hippo pathway was activated with increased phosphorylation levels of mammalian sterile 20-like kinase 1 and 2, large tumor suppressor 1 and 2, and Yes-associated protein. Compared with the model group, the levels of interleukin (IL)-17 and IL-23 were decreased, but the levels of interferon-γ, IL-4 and IL-10 were increased, in the fucoidan group. Fucoidan treatment increased natural killer cells in peripheral blood and the proportion of CD4+ T cells. Immunofluorescence detection of colorectal tumor tissues showed decreased expression of Foxp3 and up-regulated expression of CD68 in the fucoidan group. Moreover, fucoidan treatment decreased the levels of diamine oxidase and lipopolysaccharides and up-regulated the levels of tight junction proteins. 16S rDNA high-throughput sequencing revealed that fucoidan treatment decreased the abundance of Prevotella and increased the abundance of Alloprevotella. Fucoidan increased the levels of butyric acid and valeric acid compared to the model group. This study provides experimental evidence that dietary fucoidan may prevent colorectal tumorigenesis by regulating gut microecology and body immunity. Meanwhile, fucoidan activated the Hippo pathway and down-regulated the ß-catenin pathway to induce tumor cell apoptosis and suppress tumor growth.

Kumiss Supplementation Reduces Oxidative Stress and Activates Sirtuin Deacetylases by Regulating Antioxidant System.

It was aimed to investigate the effects of kumiss a fermented mare horse beverage on the sirtuin deacetylases in the oxidative stress which had been induced by 1,2-dimethyl hydrazine (DMH). Forty BALB/C male mice were divided into four groups as control, kumiss (2 × 108 cfu/mL), DMH (20 mg/kg), and kumiss + DMH (2 × 108 cfu/mL + 20 mg/kg). At the end of 20-week regimen, SIRT2, SIRT3 protein expressions by western blotting, immunolocalizations, and inhibitory anti-oxidant activity analysis in liver, colon, and kidney tissues were performed. SIRT2 and SIRT3 expressions in DMH group were decreased in liver, colon, and kidney tissues and the decrease further stimulated by kumiss reinforcement. SIRT3, a mitochondrial protein, immunostaining increased in cell nuclei of tissues in response to kumiss treatments. The oxidative stress induced by DMH was determined to increase plasma 8-OH-2-deoxyguanosine, tissue oxidative stress index, and total oxidant capacity levels. Kumiss supplement was identified to reduce these levels and increase tissue total antioxidant capacity and reduced glutathione levels. Clarifying the molecular relationship between intracellular changes in the locations of SIRT2 and SIRT3 and oxidative stress might be important with regards to developing new medical treatments in the future. The kumiss may show a protective effect against DMH-induced damage by regulating the expression of sirtuin proteins and by protecting antioxidant system.

Artesunate suppresses inflammation and oxidative stress in a rat model of colorectal cancer.

Anti-inflammatory drugs are well known to reduce the risk of colon cancer and prophylactic use of such agents is gaining acceptance as a cancer prevention therapy. As artesunate, an antimalarial drug, has been shown to exhibit chemopreventive properties, the present study was carried out to evaluate its inhibitory effect on oxidative stress and inflammation in a rat model of colon carcinogenesis. A chemical carcinogen, 1,2-dimethylhydrazine was injected twice at an interval of 1 week to induce preneoplastic lesions in the colon and the parameters indicating oxidative stress and inflammation were evaluated after 8 weeks. Artesunate (50 and 150 mg/kg) and aspirin (60 mg/kg) were administered orally throughout the study. Analysis of colon tissue revealed that both the drugs preserved histoarchitecture, inhibited cellular influx, decreased the levels of oxidative stress and inflammatory markers, downregulated cyclooxygenase-2, inducible nitric oxide synthase, nuclear factor κB, and interleukin 1ß in comparison to the experimental control. Suppression of oxidative stress and pro-inflammatory signaling by both the drugs were found to contribute to inhibition of colon carcinogenesis. The protection afforded by these drugs was found to be comparable. Our study shows that like aspirin, use of artesunate could also reduce the risk of colon cancer and it has a potential for further evaluation for the treatment purpose.

Pectin-encrusted gold nanocomposites containing phytic acid and jacalin: 1,2-dimethylhydrazine-induced colon carcinogenesis in Wistar rats, PI3K/Akt, COX-2, and serum metabolomics as potential targets.

Phytic acid (PA) has momentous chemotherapeutic potential. Due to the chelate formation and rapid elimination, it is not popular in cancer treatment. The present work was inquested to develop a surface-modified nanoformulation of PA which prevents its speedy elimination and maximizes chemotherapeutic action. Chloroauric acid was reduced with pectin to produce pectin-gold nanoparticles (PGNPs). PGNPs were incubated with PA and jacalin for drug loading and surface modifications, respectively, to form PA-loaded jacalin-pectin-gold nanoparticles (PA-J-PGNPs). Formulation(s) were assessed for various pharmaceutical/pharmacological parameters. To validate the efficacy against colon carcinogenesis, formulation(s) were assessed in 1,2-dimethylhydrazine (DMH)-treated Wistar rats. DMH treatment distorted colonic architecture, oxidative, and hemodynamic parameters, which were favorably restored by PA-J-PGNP administration. To further confirm our deliberations, formulation(s) were also examined against DMH-altered metabolic changes and expression of markers pertaining to cellular proliferation, which was reinstated by PA-J-PGNPs. Our findings establish PA formulation(s) as a promising approach for suppression of colon carcinogenesis.

Orientin mitigates 1, 2-dimethylhydrazine induced lipid peroxidation, antioxidant and biotransforming bacterial enzyme alterations in experimental rats.

BACKGROUND: Colorectal cancer (CRC) is the second most diagnosed cancer often identified during the later stages of carcinogenesis. Orientin, a C-glycoside of luteolin, is well known for its versatile therapeutic action toward oxidative stress-induced cellular response may exert chemoprevention against CRC. MATERIALS AND METHODS: In our study, we investigated the modulatory effect of orientin on lipid peroxidation, antioxidant defense, and biotransforming bacterial enzymes in 1, 2-dimethylhydrazine (DMH)-induced male albino Wistar rats in a dose-dependent manner. Animals were induced with DMH (20 mg/kg b.wt) for 15 weeks and administered with orientin in three different doses (5 mg/kg, 10 mg/kg, and 20 mg/kg b. wt) daily under distinct phases (initiation, postinitiation, and the entire) for a total treatment period of 30 weeks. RESULTS: Orientin reinstates the alterations induced by DMH on lipid peroxidation and enzymatic antioxidants through its rich-free radical scavenging properties. In addition, orientin curtails the DMH-induced augmentation of biotransforming bacterial enzymes to inhibit the colon cancer progression. Overall, experimental findings suggest that orientin significantly inhibits the DMH induced colon cancer in all the three different doses, however, maximum inhibition was observed on supplementation of 10 mg/kg b.wt for the entire period of the study. CONCLUSION: Hence, the intraperitoneal administration of 10 mg/kg b.wt orientin for the entire period is recommended for further molecular investigation to elucidate the precise mechanism of inhibition and so orientin can be used as a novel chemotherapeutic agent for CRC.

Chemopreventive effect of carvacrol on 1,2-dimethylhydrazine induced experimental colon carcinogenesis.

PURPOSE: Colorectal cancer (CRC) is a leading cause for cancer-related death and its prevention is of great importance throughout the world. Chemoprevention offers a novel approach to control the incidence of colon cancer. The present study was performed to evaluate the efficacy of carvacrol supplementation on colonic aberrant crypt foci (ACF), lipid peroxidation, and antioxidant defense system in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in male Wistar rats. MATERIALS AND METHODS: The rats were randomly divided into six groups. Group 1, control rats received modified pellet diet; Group 2 rats received modified pellet diet along with carvacrol (80 mg/kg b.wt/day); Groups 3-6 received subcutaneous injection of DMH (20 mg/kg b.wt), once a week for the first 4 weeks; in addition Groups 4-6 received carvacrol at three different doses of 20, 40, and 80 mg/kg b.wt/day for 16 weeks. RESULTS: Our result suggest that increased tumor incidence and increased number of ACF, increased bacterial enzymes accompanied by a decrease in the colonic lipid peroxidation, glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities were observed in DMH-treated rats. Administration of carvacrol to DMH-treated rats significantly decreased the tumor incidence and the number of ACF and bacterial enzymes with enhancement of colonic lipid peroxidation, GPx, SOD, and CAT activities. CONCLUSION: The results of this study suggest that carvacrol at a dose of 40 mg/kg b.wt showed a significant beneficial effect against chemically-induced colon carcinogenesis in rats.

Anti-proliferative and Apoptotic Effects of Basella rubra (L.) Against 1, 2-Dimethyl Hydrazine-induced Colon Carcinogenesis in Rats.

Colorectal cancer is a very prevalent diagnosed cancer. The current study was performed in order to examine the role of BRAE (Basella rubra aqueous extract) in regulating aberrant crypt foci (ACF) formation, cell proliferation and inhibition of apoptosis in a colon carcinogenesis model in male Wistar rats. Rats were randomly allocated into six groups. Group I served as control, and group II acted as a drug control administered BRAE (250mg/kg b.w.) orally for 30 weeks. Rats in group III-VI were given subcutaneous injections of DMH (25mg/kg b.w. weekly) for 15 weeks to initiate colon carcinogenesis. Those in group IV and VI were administered BRAE along with DMH injections. Rats in group V were administered with BRAE after cessation of DMH injection. After 30 weeks of experimental period colons were obtained from experimental groups and analyzed for ACF incidence, argyrophilic nucleolar organizing region- associated proteins (AgNOR) count, histopathological and immunohistochemical changes. Only in DMH exposed groups were ACF and AgNOR numbers increased. Administration of BRAE appreciably decreased the numbers of ACF and AgNOR in BRAE treated groups. Histopathological findings revealed a high level of dysplastic changes with decreased number of goblet cells found only in only DMH injected rats. Administration of BRAE in treated group rats reversed these changes. Expression markers for cell proliferation (PCNA and Ki67) were elevated in DMH treated rats, but reduced with BRAE treatement. This expression was reversed with apoptosis markers (p53 and Caspase-3). Thus the results results of the present study were found to be significant and confirmed the potential efficacy of BRAE against colon carcinogenesis.

Expression of metallothionein in dimethylhydrazine-induced colonic precancerous and cancerous model in rat.

AIM: Metallothionein (MT) is a small protein with a high affinity for divalent heavy metals and has a function in zinc homeostasis. The purpose of this study was to assess the MT mRNA gene expression as well as the MT protein content by immunohistochemistry and radioimmunoassay (RIA) in 1,2-dimethylhydrazine (DMH)-induced precancerous and cancerous colonic tissue in rats. MATERIALS AND METHODS: Six-week-old rats were given subcutaneous injections of DMH twice a week for 3 months and sacrificed at 4 months (precancerous model) and 6 months (cancerous model). We determined MT mRNA expression by reverse transcription polymerase chain reaction and MT protein content by both immunohistochemical expression and cadmium-109 RIA. RESULTS: MT mRNA expression in the large intestine showed statistically significant decrease in the precancerous (P < 0.01) and the cancerous (P < 0.001) model as compared with controls. Immunohistochemical expression of MT showed statistically significant decrease (P < 0.05) in the colonic cancerous tissue. MT content in the large intestine showed statistically significant decrease in precancerous (P < 0.005) and cancerous (P < 0.001) model as compared with controls. CONCLUSION: This study suggests that a decrease in the colonic MT mRNA expression, MT protein expression, and content in DMH-induced colonic cancer model is associated with the development of preneoplastic lesions and further progression to carcinoma in the colon results in a greater reduction in the levels of each of these parameters.

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. Molecular docking of ligand protein interaction was done to validate the in vivo results. Cyclin D1, cyclin E, CDK2, and CDK4 were overexpressed in DMH, whereas piroxicam and c-phycocyanin promoted the cell cycle arrest by downregulating them. Both drugs mediated apoptosis through p53 activation. Piroxicam and c-phycocyanin also stimulated antiproliferation by restraining PCNA expression and reduced cell survival via inhibiting NFκB (p65) pathway. Molecular docking revealed that phycocyanobilin (a chromophore of c-phycocyanin) interact with DNA binding site of NFκB. Inhibition of cyclin/CDK complex by piroxicam and c-phycocyanin affects the expression of p53 in colon cancer followed by downregulation of NFκB and PCNA levels, thus substantiating the antineoplastic role of these agents.

Cyclooxygenase as a target in chemoprevention by probiotics during 1,2-dimethylhydrazine induced colon carcinogenesis in rats.

The present study was undertaken to assess the effects of potential probiotics in regulating the activity of cyclooxygenase-2 (COX-2) along with other morphological and histological analysis during 1,2-dimethylhydrazine (DMH) induced colon carcinogenesis in rats. The rats were divided into 6 groups viz., normal control, Lactobacillus plantarum (AdF10) treated, Lactobacillus rhamnosus GG (LGG) treated, DMH treated, AdF10 + DMH treated and LGG + DMH treated. Probiotics were supplemented to rats at dose levels of 2 × 10(10) cells per day for 6 days in a week. All the treatments were continued for a period of 16 wk. DMH treatment resulted in a statistically significant increase in the levels of total sialic acid (TSA). However, on supplementation with probiotics, a significant reduction in TSA was observed. DMH treatment brought about a significant increase in the expression of COX-2. But, supplementation of probiotics brought down the protein expression to moderate level. Further, supplementation with probiotics was also able to reduce tumor incidence, tumor multiplicity and average tumor size. Therefore, treatment with probiotics has the potential of providing protection against colon cancer by suppressing the COX-2 expression as one of the protective mechanisms.

Probiotic Escherichia coli CFR 16 producing pyrroloquinoline quinone (PQQ) ameliorates 1,2-dimethylhydrazine-induced oxidative damage in colon and liver of rats.

Inflammation of the gastrointestinal tract is associated with reactive oxygen species (ROS) genesis. Alleviation of oxidative stress is achieved by using antioxidants and probiotics. Present study investigates a synergistic effect of the probiotic Escherichia coli CFR 16 containing Vitreoscilla haemoglobin gene (vgb), green fluorescent protein (gfp) gene and pyrroloquinoline quinone (pqq) gene cluster on oxidative stress induced by 1,2-dimethylhydrazine (DMH). Adult virgin Charles foster male rats (3-4 months) weighing 200-250 g were administered with DMH (25 mg/kg body weight, s.c.) twice a week for eight consecutive weeks. Rats receiving only DMH dose showed increased lipid peroxidation in liver and intestinal tissues with reduced activity of antioxidant enzymes, i.e. superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Oral dose of E. coli CFR 16::vgb-gfp harbouring pqq gene cluster increased rat faecal PQQ concentration by twofold, reduced lipid peroxidation and retained SOD, CAT and GPx activities close to normal levels in liver and colonic tissues following DMH treatment. In addition, significant protection was found in colonic histological sections of these rat groups. This study demonstrates a protective efficacy in the following order: E. coli CFR 16 < E. coli CFR 16::vgb-gfp < vitamin C = PQQ < E. coli CFR 16::vgb-gfp (pqq).

Wild-type K-ras has a tumour suppressor effect on carcinogen-induced murine colorectal adenoma formation.

K-ras mutations are found in ~40% of human colorectal adenomas and carcinomas and contribute to colorectal tumour formation at an early stage. Wild-type K-ras has been reported to be deleted in some tumours, but the consequences of changes in wild-type K-ras copy number for experimental colorectal carcinogenesis have not been investigated. To characterize the effects of K-ras copy number changes on formation of carcinogen-induced colorectal neoplasms in mice, wild-type (K-ras(+/+) ) and heterozygous K-ras exon 1 knockout (K-ras(+/-) ) mice were given 10 weekly treatments of 1, 2-dimethylhydrazine (DMH) to induce colorectal tumours. Colorectal expression levels of K-ras 4A and 4B transcripts in K-ras(+/-) mice were ~50% decreased compared with K-ras(+/+) mice. One year after DMH treatment, survival of K-ras(+/-) mice decreased from 88 to 82% compared with wild-type mice. Colorectal adenomas significantly increased from 0.52 ± 0.15 in K-ras(+/+) mice to 0.87 ± 0.14 in K-ras(+/-) mice (mean ± SEM per mouse, P < 0.01); total tumour volume increased 2.13-fold (P < 0.05). Comparing K-ras(+/+) with K-ras(+/-) murine adenomas, Ki-67-positive proliferating tumour cells significantly increased from 7.77 ± 0.64% to 9.15 ± 0.92% and cleaved caspase-3-positive apoptotic tumour cells decreased from 1.40 ± 0.37% to 0.80 ± 0.22% (mean ± SEM, P < 0.05 for both). No K-ras or B-raf mutations were detected in the adenomas. Immunohistochemical studies showed no significant changes in extracellular signal regulating kinase/mitogen-activated protein kinase (Erk/MapK) or PI3K/Akt pathway activation in the adenomas. In conclusion, the data collectively show that a 50% reduction in K-ras gene dosage and RNA expression promoted experimental colorectal tumourigenesis, consistent with wild-type K-ras having a tumour suppressor effect on carcinogen-induced murine colorectal adenoma formation.

Modulating effect of d-carvone on 1,2-dimethylhydrazine-induced pre-neoplastic lesions, oxidative stress and biotransforming enzymes, in an experimental model of rat colon carcinogenesis.

OBJECTIVES: The present study has aimed to evaluate chemopreventive potential of d-carvone on oxidative stress markers, biotransforming enzymes, incidence of colonic polyps and aberrant crypt foci (ACF) in 1,2-dimethylhydrazine (DMH)-induced experimental colon carcinogenesis. MATERIALS AND METHODS: Rats were randomly divided into six groups, with group I serving as control. Group II animals received d-carvone every day orally (20 mg/kg body weight) for 16 weeks; groups III-VI received subcutaneous injections of DMH (20 mg/kg body weight) once a week, for the first 4 weeks. In addition, groups IV-VI received different doses of d-carvone (5, 10 and 20 mg/kg body weight everyday orally) along with DMH injections. RESULTS: Our results revealed that supplementation with d-carvone significantly reduced incidence of polyps/ACF and ACF multiplicity in DMH-exposed rats compared to DMH-alone-exposed rats. Moreover, our results showed reduced activities of liver and circulatory antioxidants and increased levels of lipid peroxidation by products in DMH-exposed animals, which were significantly reversed on supplementation with d-carvone. In addition, colonic antioxidants and lipid peroxidation were significantly diminished in DMH-exposed rats, which were significantly elevated on supplementation with d-carvone. Furthermore, we also determined activities of biotransforming enzymes, which were found to be altered in DMH-exposed rats, but reversed on d-carvone supplementation. All these observations of changes were supported by histochemical findings. CONCLUSION: Overall, results obtained from this study suggest that d-carvone at 10 mg/kg body weight provided optimum protection and could be used as an effective chemopreventive agent against colon carcinogenesis induced by DMH.