Effect of mesenchymal stem cells on cytochrome-c release and inflammation in colon cancer induced by 1,2-dimethylhydrazine in Wistar albino rats

Colon cancer is one of the most common causes of deaths by cancer worldwide. Stem cells have immunosuppressive properties that promote tumor targeting and circumvent obstacles currently in gene therapy. Bone marrow stem cells are believed to have anticancer potential. The transplantation of mesenchymal stem cells (MSCs), a type of bone marrow stem cells, has been considered a potential therapy for patients with solid tumors due to their capability to enhance the immune response; MSC transplantation has received renewed interest in recent years. The present study aimed to evaluate the antiapoptotic effects of the MSCs on 1,2-dimethylhydrazine (DMH)-induced inflammation in the rat model of colorectal cancer. The rats were randomly allocated into four groups: control, treated with MSCs, induced by DMH, and induced by DMH and treated with MSCs. The MSCs were intra-rectally injected, and DMH was subcutaneously injected at 20 mg/kg body weight once a week for 15 weeks. The administration of MSCs into rats starting from day 0 of the DMH injection was found to enhance the histopathological picture. The MSC treatment resulted in fewer inflammatory cells than in the DMH group. Therefore, our findings suggest that BMCs have antitumor effects by modulating the cellular redox status and down-regulating the pro-inflammatory genes. Thus, BMCs may provide therapeutic value for colon cancer treatment.     

DNA damage and aberrant crypt foci as putative biomarkers to evaluate the chemopreventive effect of annatto (Bixa orellana L.) in rat colon carcinogenesis

Chemoprevention opens new perspectives in the prevention of cancer and other degenerative diseases. Use of target-organ biological models at the histological and genetic levels can markedly facilitate the identification of such potential chemopreventive agents. Colon cancer is one of the highest incidence rates throughout the world and some evidences have indicated carotenoids as possible agents that decrease the risk of colorectal cancer. In the present study, we evaluate the activity of annatto (Bixa orellana L.), a natural food colorant rich in carotenoid, on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) in rat colon. Further, we investigate, the effect of annatto on DMH-induced DNA damage, by the comet assay. Male Wistar rats were given s.c. injections of DMH (40 mg/kg body wt.) twice a week for 2 weeks to induce ACF. They also received experimental diets containing annatto at 20, 200 or 1000 ppm for five 5 weeks before (pre-treatment), or 10 weeks after (post-treatment) DMH treatment. In both protocols the rats were sacrificed on week 15th. For the comet assay, the animals were fed with the same experimental diets for 2 weeks. Four hours before the sacrifice, the animals received an s.c. injection of DMH (40 mg/kg body wt.). Under such conditions, dietary administration of 1000 ppm annatto neither induce DNA damage in blood and colon cells nor aberrant crypt foci in rat distal colon. Conversely, annatto was successful in inhibiting the number of crypts/colon (animal), but not in the incidence of DMH-induced ACF, mainly when administered after DMH. However, no antigenotoxic effect was observed in colon cells. These findings suggest possible chemopreventive effects of annatto through their modulation of the cryptal cell proliferation but not at the initiation stage of colon carcinogenesis.     

Modulatory efficacy of hesperetin (citrus flavanone) on xenobiotic-metabolizing enzymes during 1,2-dimethylhydrazine-induced colon carcinogenesis

Colorectal cancer is the second leading cause of cancer death worldwide with diet playing a prominent role in disease initiation and progression. Diet and nutrition play an important role during this multistep colon carcinogenic process. We have investigated the modulatory efficacy of hesperetin on aberrant crypt foci (ACF) and xenobiotic-metabolizing enzymes on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. Male albino Wistar rats were randomly divided into six groups. Group 1 served as control, received modified pellet diet and group 2 rats received 20 mg/kg body weight of hesperetin p.o. every day. Groups 3-6 rats were given subcutaneous injections of 1,2-dimethylhydrazine (20 mg/kg body weight) once a week for 15 weeks to induce ACF in the colon. In addition, rats in group 4 received hesperetin as in group 2 orally for the first 15 weeks (initiation), group 5 rats received hesperetin as in group 2 after the last injection of DMH and continued till the end of the experimental period (post-initiation). Group 6 received hesperetin as in group 2 throughout the entire period of 32 weeks. DMH exposure showed high incidence (90%) of ACF (280 ± 24.5 aberrant crypt/colon) and dysplastic ACF, elevated activities of phase I enzymes and reduced the activities of phase II enzymes in the liver and colonic mucosa of colon cancer bearing rats. Hesperetin supplementation significantly reversed these effects, the effect being more pronounced in group 6 rats (hesperetin supplemented throughout the study period).These findings suggest that hesperetin can significantly reduce the formation of preneoplastic lesions and effectively modulate the xenobiotic-metabolizing enzymes in rats.     

Protective role of luteolin in 1,2-dimethylhydrazine induced experimental colon carcinogenesis

The aim of the present study was to unravel the chemopreventive effect of luteolin on bacterial enzymes such as beta-glucuronidase and mucinase in a colon carcinogenesis model induced by 1, 2-dimethyl hydrazine (DMH). Twenty mg/kg body weight of DMH were administered subcutaneously once a week for the first 15 weeks and then discontinued. Luteolin (0.1, 0.2, or 0.3 mg/kg body weight/everyday (p.o.) was administered in a dose dependent manner at the initiation and also at the post-initiation stages of carcinogenesis to DMH treated rats. The animals were sacrificed at the end of 30 weeks. Colon cancer incidence and the activities of bacterial enzymes beta-glucuronidase (in the proximal colon, distal colon, intestines, liver and colon contents) and mucinase (colon and fecal contents) were significantly increased in DMH -treated rats compared to the control rats. On luteolin administration, colon cancer incidence, number of tumors per rat and the activities of beta-glucuronidase and mucinase, were significantly decreased both in the initiation and post-initiation stages of colon carcinogenesis dependent on the three different doses given. The increase in beta-glucuronidase activity may augment the hydrolysis of glucuronide conjugates, liberating toxins, while the increase in the mucinase activity may enhance the hydrolysis of the protective mucins in the colon. Thus our results demonstrate for the first time that luteolin, a dietary flavonoid, exerts chemopreventive and anticarcinogenic effects against DMH induced colon cancer.     

Effects of 2.45-GHz microwave radiation and phorbol ester 12-O-tetradecanoylphorbol-13-acetate on dimethylhydrazine-induced colon cancer in mice

The purpose of this study was to investigate the effects of 2.45 GHz microwave (MW) radiation on dimethylhydrazine (DMH)-induced colon cancer in mice. The subjects were 115 Balb/c mice 4 weeks of age. The animals were divided into group A (control), group B (DMH), group C (DMH + MW), and group D [DMH + 12-O-tetradecanoylphorbol-13-acetate (TPA)]. Radiation (10 mW/cm²) was delivered dorsally with the E field parallel to the mouse's long body axis in an anechoic chamber. Radiations were administered 3 hr daily, 6 days per week, over a period of 5 months. The average SAR was estimated to be 10–12 W/kg. During the course of radiation treatments, DMH was injected once per week. The tumor promoter TPA was administered once per week for 10 weeks, from the third week on, after the initial treatment. The incidence of tumors did not significantly differ between the three test groups (groups B, C, and D; P > 0.25). However, the number of tumors, the size of the tumors, and the incidence of protuberant and infiltrative types in tumor-bearing animals were higher in group D compared to groups B and C (P < 0.05). No difference was found between groups B and C (P > 0.25). The study indicates that 2.45 GHz microwave radiation at 10 mW/cm² power density did not promote DMH-induced colon cancers in young mice. The study also showed that TPA could accelerate colon tumor production if a tumor was initiated. © 1994 Wiley-Liss, Inc.     

Effects of ovariectomy on microsatellite instability in rat colon tumors induced by 1,2-dimethylhydrazine

To study the effects of ovariectomy on tumorigenesis and microsatellite instability (MSI) in rat colon tumors induced by 1,2-dimethylhydrazine, to elucidate the association between postmenopausal ovarian hormones depletion and MSI pathway in colorectal tumorigenesis. Forty female Wistar rats were randomly divided into two groups: Ovariectomized (Ovx) group and Sham-ovariectomized (Sham-Ovx) group. All rats were injected intraperitoneally with 1,2-dimethylhydrazine (DMH) (20 mg/kg b.w) once a week for 20 weeks. Ten weeks after the final DMH injection, all the rats were sacrificed to collect tumors. Microsatellite instability of six microsatellite loci was detected using fluorescent PCR followed by fragment analysis on automatic DNA sequencer with GeneScan 3.7 software. The tumor multiplicity in the OVX group was significantly higher than that in the Sham-OVX group (3.6 ± 1.4 vs. 2.4 ± 1.6, P < 0.05). The incidence of MSI-positive tumors in OVX group was higher than that in Sham-OVX group (32.1 vs. 10.8%, P < 0.05).The incidence of tumors showing MSI at multiple loci in OVX group was also higher than that in Sham-OVX group (18.9 vs. 2.7%, P < 0.05). Ovariectomy increased tumor formation and the frequency of MSI in DMH-induced colon tumors. It implied that postmenopausal ovarian hormones depletion might influence colorectal tumorigenesis through MSI pathway.     

Tumor-enhancing effects of cholic acid are exerted on the early stages of colon carcinogenesis via induction of aberrant crypt foci with an enhanced growth phenotype.

The objective of the study was to establish whether cholic acid (CHA) enhanced colonic tumor incidence in the early phase of carcinogenesis. Male, Sprague-Dawley rats (n = 180) were injected twice with azoxymethane (AOM) (15 mg x kg(-1) body weight x week(-1), s.c., given 1 week apart). Following the first AOM injection, animals were randomly assigned to two groups, control AIN-93G diet (CON) or control diet containing 0.2% CHA by weight (CHA). Three weeks after the first injection, 20 animals (10 animals/group) were killed and aberrant crypt foci (ACF) were enumerated. The remaining animals were further subdivided and animals randomly assigned to CON or CHA diets, creating four treatments: CON-CON, CON-CHA, CHA-CHA, and CHA-CON. After 3, 12, and 20 weeks (following the first carcinogen injection), the animals were killed and the number and crypt multiplicity of ACF enumerated. Macroscopic tumors were evaluated at week 20. Total ACF were not different between groups. Average crypt multiplicity and medium (4-6 crypts/focus) and large (> or = 7 crypts/focus) ACF were greater in CHA-CHA and CHA-CON compared with CON-CON and CON-CHA (p < 0.01). Transient exposure to CHA (CHA-CON) was sufficient to induce development of ACF with an accelerated growth phenotype and elicit a tumor-enhancing effect. CHA-CHA had the highest tumor incidence (82.8%, p < 0.05) followed by CHA-CON (56.7%, p < 0.05), and tumor multiplicity and number of tumors per rat in CHA-CON were similar to CHA-CHA (2.29 and 1.3 versus 2.33 and 1.9, respectively). Delayed intervention with CHA (CON-CHA) produced a tumor outcome similar to CON-CON (31 and 30%, respectively), it did not enhance colonic tumor incidence. Taken collectively these results suggest CHA was effective in enhancing colon carcinogenesis during early phases and ineffective in post-initiation phases.     

Chemopreventive efficacy of green tea drinking against 1,2‐dimethyl hydrazine‐induced rat colon carcinogenesis

Colorectal cancer is one of the leading causes of tumour‐related deaths. In the present study, the chemopreventive effect of green tea on 1,2‐dimethylhydrazine (DMH)‐induced colon carcinogenesis was studied in male Wistar rats. The DMH group received subcutaneous injections of DMH (30 mg kg^?1 body weight) once a week for 30 weeks, the normal group received the vehicle of DMH, and the DMH + green tea group received DMH simultaneously with 1% green tea as their sole source of drinking fluid throughout the experimental period. In the DMH group treated with green tea, significant reductions in gene overexpressions of colonic nuclear factor κB (NF‐κB), tumour necrosis factor α, inducible nitric oxide synthase and cyclooxygenase 2, and NF‐κB immunostaining indicates the anti‐inflammatory effect of green tea in attenuating colon cancer. Moreover, the anti‐angiogenic and anti‐invasiveness effects of green tea were revealed as reductions of both vascular endothelial growth factor and matrix metalloproteinase‐7 mRNA expression levels. These effects were confirmed by the significant reduction of serum tumour necrosis factor α, C‐reactive protein levels, inhibition of tumour incidence, and nearly normal survival rate and colonic architecture. It can be concluded that green tea exerts a potent chemopreventive effect on colon carcinogenesis possibly due to the inhibition of NF‐κB. Copyright © 2012 John Wiley & Sons, Ltd.     

Vanadium inhibits placental glutathione S-transferase (GST-P) positive foci in 1,2-dimethyl hydrazine induced rat colon carcinogenesis

Vanadium (V) has recently been found to possess potent anti-neoplastic activity in rat colon carcinogenesis. In the present study attempts have been made to investigate the expression of the number and area of aberrant crypt foci positive for placental glutathione S-transferase (GST-P) during 1,2-dimethyl hydrazine (DMH)-induced rat colon carcinogenesis. Male Sprague Dawley rats were randomly divided into four groups. Rats in group A were designed as normal controls. Group B animals received DMH once a week (20 mg/kg body wt.) intraperitoneally for 16 weeks. Group C rats received the same treatment of DMH as in group B, along with 0.5-ppm vanadium as ammonium monovanadate ad libitum in drinking water throughout the experiment. Vanadium alone was given to Group D rats without any DMH injection. The expression of the number and the area of aberrant crypt foci (ACF) positive for GST-P was maximum in DMH-treated group. Vanadium-treated rats significantly reduced (P < 0.001) the expression of GST-P positive ACF cells (by 71.13%) for the entire period of the study. Moreover the histopathological examination also showed that vanadium action could minimize the aberrant crypt foci (P < 0.001). Furthermore, vanadium supplementation also elevated SOD activities in both liver and colon (P < 0.01, P < 0.02 and P < 0.01, P < 0.02 respectively) when compared to their carcinogen counterparts. Our results confirm that vanadium is particularly effective in limiting the action of the carcinogen, thereby establishing its anticarcinogenicity in chemically induced rat colon carcinogenesis.     

Carnitines slow down tumor development of colon cancer in the DMH‐chemical carcinogenesis mouse model

Dietary agents are receiving much attention for the chemoprevention of cancer. While curcumin is known to influence several pathways and affect tumor growth in vivo, carnitin and its congeners play a variety of important metabolic functions: are involved in the oxydation of long‐chain fatty acids, regulate acyl‐CoA levels and influence protein activity and stability by modifying the extent of protein acetylation. In this study we evaluated the efficacy of carnitines in the prevention of cancer development using the 1,2,‐dimethylhydrazine (DMH)‐induced colon carcinogenesis model. We also assessed whether their combination was able to give rise to increased protection from cancer development. Mice treated with DMH were dosed orally with curcumin and/or carnitine and acylcarnitines for 20 weeks. At the end of the treatment colon samples were collected, and scored for multiple ACF and adenomas. We observed that carnitine and acyl‐carnitines had same, if not higher, efficacy than curcumin alone in inhibiting the formation of neoplastic lesions induced by DMH treatment. Interestingly, the combination of curcumin and acetyl‐L ‐carnitine was able to fully inhibit the development of advanced adenoma lesions. Our data unveil the antitumor effects of carnitines and warrant additional studies to further support the adoption of carnitines as cancer chemopreventative agents. J. Cell. Biochem. 114: 1665–1673, 2013. © 2013 Wiley Periodicals, Inc.     

Novel mucilage fraction of Sinapis alba L. (mustard) reduces azoxymethane-induced colonic aberrant crypt foci formation in F344 and Zucker obese rats

Seeds of Sinapis alba Linn. (commonly called yellow or white mustard) and their components have been reported to possess anticancer properties. In this study, we evaluated the efficacy of a novel mucilaginous fraction of mustard seeds in inhibiting colonic preneoplastic changes in animal models of sporadic and obesity-associated colon cancer. In two separate studies, male Sprague-Dawley or female Zucker obese rats, injected with azoxymethane (15 or 10 mg/kg body wt. once a week for 2 weeks, respectively), were fed AIN-93G diets with or without 5% mustard mucilage (MM) (w/w) for 8 weeks. Our aim was to measure the ability to modulate the number of aberrant crypt foci (ACF), putative preneoplastic lesions of the colon. The data were classified into total numbers of ACF and large ACF (crypt multiplicity of 4 or more). We report here that 5% MM significantly (p<0.05) decreased the number of total (approximately 21% inhibition) and large (approximately 50% inhibition) ACF in the colons of Sprague-Dawley rats compared to that in untreated controls. In addition, 5% MM supplemented diet significantly lowered (p<0.05) the number of total (approximately 63% inhibition) and large (approximately 60% inhibition) colonic ACF in Zucker obese rats compared to untreated obese rats, and had no effect on fasting plasma cholesterol or triglyceride levels. These results demonstrate the possible role of MM as a functional food against sporadic and obesity-associated colon cancer, and provide impetus to conduct research to understand the underlying mechanism(s) of action.     

Adiponectin deficiency: role in chronic inflammation induced colon cancer

Adiponectin (APN), an adipokine, exerts an anti-inflammatory and anti-cancerous activity with its role in glucose and lipid metabolism and its absence related to several obesity related malignancies including colorectal cancer. The aim of this study is to determine the effect of APN deficiency on the chronic inflammation-induced colon cancer. This was achieved by inducing inflammation and colon cancer in both APN knockout (KO) and C57B1/6 wild type (WT) mice. They were divided into four treatment groups (n=6): 1) control (no treatment); 2) treatment with three cycles of dextran sodium sulfate (DSS); 3) weekly doses of 1,2-dimethylhydrazine (DMH) (20mg/kg of mouse body weight) for twelve weeks; 4) a single dose of DMH followed by 3 cycles of DSS (DMH+DSS). Mice were observed for diarrhea, stool hemoccult, and weight loss and were sacrificed on day 153. Tumor area and number were counted. Colonic tissues were collected for Western blot and immunohistochemistry analyses. APNKO mice were more protected than WT mice from DSS induced colitis during first DSS cycle, but lost this protection during the second and the third DSS cycles. APNKO mice had significantly severe symptoms and showed greater number and larger area of tumors with higher immune cell infiltration and inflammation than WT mice. This result was further confirmed by proteomic study including pSTAT3, pAMPK and Cox-2 by western blot and Immunohistochemistry. Conclusively, APN deficiency contributes to inflammation-induced colon cancer. Hence, APN may play an important role in colorectal cancer prevention by modulating genes involved in chronic inflammation and tumorigenesis.     

The modulatory influence of p-methoxycinnamic acid, an active rice bran phenolic acid, against 1,2-dimethylhydrazine-induced lipid peroxidation, antioxidant status and aberrant crypt foci in rat colon carcinogenesis

We investigated the chemopreventive effect of p-methoxycinnamic acid (p-MCA), an active phenolic acid of rice bran, turmeric, and Kaemperfia galanga against 1,2-dimethylhydrazine-induced rat colon carcinogenesis. Male albino Wistar rats were randomly divided into six groups. Group 1 consisted of control rats that received a modified pellet diet and 0.1% carboxymethyl cellulose. The rats in Group 2 received a modified pellet diet supplemented with p-MCA [80 mg/kg body weight (b.wt.) post-orally (p.o.)] everyday. The rats in Groups 3-6 received 1,2-dimethylhydrazine (DMH) (20 mg/kg b.wt.) via subcutaneous injections once a week for the first 4 weeks; additionally, the rats in Groups 4, 5 and 6 received p-MCA at doses of 20, 40 and 80 mg/kg b.wt./day p.o., respectively, everyday for 16 weeks. The rats were sacrificed at the end of the experimental period of 16 weeks. The DMH-treated rats exhibited an increased incidence of aberrant crypt foci (ACF) development; an increased crypt multiplicity; decreased concentrations of tissue lipid peroxidation markers such as thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and lipid hydroperoxides (LOOH); decreased levels of tissue enzymic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR); and decreased levels of non-enzymic antioxidants such as reduced glutathione (GSH) and vitamins C, E and A in the colon. Supplementation with p-MCA significantly reversed these changes and significantly inhibited the formation of ACF and its multiplicity. Thus, our findings demonstrate that p-MCA exerts a strong chemopreventive activity against 1,2-dimethylhydrazine-induced colon carcinogenesis by virtue of its ability to prevent the alterations in DMH-induced circulatory and tissue oxidative stress and preneoplastic changes. p-MCA was more effective when administered at a dose of 40 mg/kg b.wt. than at the other two doses tested.     

Dietary copper and dimethylhydrazine affect protein kinase C isozyme protein and mRNA expression and the formation of aberrant crypts in colon of rats.

Low dietary copper has been shown to decrease the expression of various protein kinase C (PKC) isozymes and increase the risk of colon cancer development in experimental animals. The purpose of this study was to investigate the relationship between dietary copper and carcinogen administration on PKC isozyme accumulation and aberrant crypt foci (ACF) formation in rats fed 0.9 and 7.7 microg Cu/g diet. After 24 and 31 d on the diets, the rats were injected with either dimethylhydrazine (DMH) (25 mg/kg i.p.) or saline and killed at two time points (2 wk and 8 wk after DMH). Rats fed low dietary copper had significantly lower (p<0.0001) hematocrits, hemoglobin, ceruloplasmin activity and plasma and liver copper concentrations than rats fed adequate dietary copper. Ingestion of low dietary copper significantly (p<0.005) increased the formation of DMH-induced ACF (116.8 vs 59.6). Low dietary copper significantly (p<0.05) decreased the concentration of PKC alpha, delta, and zeta in the colon at 2 wk but not at 8 wk. Thus, changes in PKC isoform protein concentration may be related to increased susceptibility of copper-deficient animals to colon cancer.     

Suppressive effect of an inducible nitric oxide inhibitor, ONO-1714, on AOM-induced rat colon carcinogenesis.

The expression of inducible nitric oxide synthase (iNOS) is markedly elevated in rat colon cancers induced by azoxymethane (AOM). In addition, iNOS can be detected in most adenomas and dysplastic aberrant crypt foci (ACF), suggesting that iNOS plays an important role in colon carcinogenesis. In the present study, the effect of an iNOS inhibitor, ONO-1714 ((1S,5S,6R,7R)-7-chloro-3-imino-5-methyl-2-azabicyclo[4.1.0] heptane hydrochloride), on AOM-induced rat colon carcinogenesis was investigated. Male F344 rats were treated with 15 mg/kg body weight of AOM once a week, for 2 weeks. ONO-1714 was given to the rats at doses of 10, 20, 50, and 100 ppm in diet for 4 weeks from the day before the first carcinogen treatment. The number of AOM-induced ACF in the rats receiving 10, 20, 50 and 100 ppm ONO-1714 were 94, 73 (P < 0.05), 71 (P < 0.005), and 53% (P < 0.0005), respectively, of the control value. Moreover, the mean number of aberrant crypts per focus was significantly lowered in 100 ppm ONO-1714 group (P < 0.05). Then, the effects of long-term treatment (32 weeks) with 50 and 100 ppm ONO-1714 on AOM-induced colorectal tumor development were examined. Although incidences and multiplicities of colon tumors did not significantly differ among the groups, number of tumors developing in the middle part of colon were reduced with both 50 and 100 ppm doses (P < 0.05). Furthermore, colon tumor volume tended to be decreased by ONO-1714 treatment, and the number of colon tumors more than 3mm in diameter was significantly lowered in the 100 ppm ONO-1714 group (P < 0.01). These results suggest that iNOS plays roles in both early and late stages of colon carcinogenesis.     

In vitro and in vivo treatment of colon cancer by VIP antagonists

Vasoactive intestinal peptide (VIP) is secreted from many cancer lines and VIP binding was observed in many tumors. We have shown before that VIP antagonists are potent inhibitors of neoplastic growth of neuroblastoma, lung and breast cancer cells in vitro. Here, the cultured colon cancer cell line HCT-15 that exhibited VIP receptor expression was treated with the VIP hybrid antagonist neurotensin(6-11)VIP(7-28). The antineoplastic activity was assessed by thymidine incorporation. Neurotensin(6-11)VIP(7-28) efficiently inhibited cancer growth with a maximal effect at nanomolar concentrations. Once the inhibitory properties of the VIP antagonist on colon cancer cells were established, the in vivo curative effects were analyzed. Sprague-Dawley rats were injected with azoxymethane (AOM) (15 mg/kg/week) for 2 weeks, providing artificial induction of colon tumors. The rats were then allocated into four experimental groups: (1) receiving no treatment; (2) receiving treatment with saline; (3, 4) receiving treatment with 10 or 20 microg of neurotensin(6-11)VIP(7-28), respectively. After 10 weeks of daily injections, rats were sacrificed and tumors assessed for stage, volume, location, differentiation and lymphocytic infiltrate. Embedded mucosa was assessed for dysplastic crypts. Results showed that the antagonist treatment reduced the tumor volume, staging, lymphocyte infiltrate and the number of dysplastic crypts. Thus, neurotensin(6-11)VIP(7-28) could serve as an effective cancer treatment and a preventing agent.     

Role of oregano on bacterial enzymes in 1,2-dimethylhydrazine-induced experimental colon carcinogenesis

Colon cancer incidence is higher in developed countries than in developing countries. We determined the effect of oregano (Origanum vulgare L.) on fecal bacterial enzyme activities in 1,2-dimethylhydrazine (DMH)-induced experimental colon carcinogenesis in rats. Male Wistar albino rats were divided into 6 groups and all animals were fed with a high-fat diet (20% fat in the diet). Group 1 served as control and group 2 animals received 60 mg.kg(-1) body weight (b.w.) oregano daily for 15 weeks. To induce colon cancer, DMH (20 mg.kg(-1) b.w.) was injected subcutaneously once a week for the first 4 weeks (groups 3-6). In addition, oregano was administered at 20, 40, or 60 mg.kg(-1) b.w. each day orally for the entire 15 weeks (groups 4-6). We analyzed the fecal bacterial enzyme activities and found it to be significantly higher in the group treated with DMH alone than in the control group. Oregano supplementation at all 3 doses significantly suppressed the bacterial enzyme activities and modulated oxidative stress significantly compared with the unsupplemented DMH-treated group. Results of our present investigation therefore revealed that oregano markedly inhibited DMH-induced colon carcinogenesis and that the optimal dose of 40 mg.kg(-1) b.w. was more effective than either the higher or lower doses.     

Detection of vascular endothelial growth factor in colon cancer xenografts using bevacizumab based near infrared fluorophore conjugate

Background

The aim of this study was to develop the near infrared fluorescence (NIRF)-based imaging agent for the visualization of vascular endothelial growth factor (VEGF) in colon cancer. AlexaFluor 750 conjugating with bevacizumab, and injected intravenously into nude mice bearing VEGF over-expressing HT29 human colorectal cancer. Optical imaging was performed at 15 min, 24 h and 48 h post injection. Immunofluorescences staining of the tumor sections were performed. HT29 colorectal cancer xenografts were clearly visualized with bevacizumab-AlexaFluor 750.

Results

Ex vivo analysis showed 2.1 ± 0.4%, 37.6 ± 6.3% and 38.5 ± 6.2% injected dose/g accumulated in the tumors at 15 min, 24 h and 48 h respectively. Tumor uptake was significantly decreased in pretreated with excess of bevacizumab (p = 0.002). Immunofluorescence analysis showed strong staining of anti-CD 31 antibody around the blood vessels. Anti-VEGF-A and bevacizumab showed heterogeneous expression throughout the tumor.

Conclusions

Current study successfully detected the VEGF expression in HT29 colorectal cancer xenografts, signifying as a potential agent for non-invasive imaging of VEGF expression, which may be applied in clinical practice.     

Multivitamin and mineral supplementation in 1,2-dimethylhydrazine induced experimental colon carcinogenesis and evaluation of free radical status, antioxidant potential, and incidence of ACF

This study was performed to determine the chemopreventive and antioxidant status of multivitamin and mineral (0.01% in drinking water, ad libitum) supplements in 1,2-dimethylhydrazine (DMH)-induced experimental colon carcinogenesis. Experimental colon carcinogenesis was induced in male albino Wistar rats by injecting DMH (20 mg·(kg body mass)(-1)) once weekly for 15 consecutive weeks, and administering a multivitamin supplement in 3 regimes (initiation, post-initiation, and entire experimental period) for 32 weeks. We studied lipid peroxidation products (thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes) in the circulation and in the tissues, antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and non-enzymatic antioxidant-reduced glutathione) of the tissues, aberrant crypt foci (ACF), and histopathological alterations. DMH-induced rats had an increase in lipid peroxidation products and a lower antioxidant status compared with control animals. Multivitamin and mineral supplementation during the initiation, post-initiation, and the entire study period significantly decreased the levels of lipid peroxidation products in circulation and colonic tissues, significantly elevated the activities of the antioxidant enzymes and reduced glutathione to near normalcy in DMH-induced rats. The incidence of ACF was reduced by [corrected] 84.1% in rats supplemented with multivitamin and minerals for the entire study and prevented the colonic tissue from histopathological alterations induced by DMH.