Tissue zinc levels in precancerous tissue in the gastrointestinal tract of azoxymethane (AOM)-treated rats

Elevated luteinizing hormone receptor signaling or selenium treatment leads to comparable changes in adrenal cortex histology and androgen-AR/ZIP9 signaling

The importance and regulation of adrenal androgen production and signaling are not completely understood and are scarcely studied. In addition, there is still a search for appropriate animal models and experimental systems for the investigation of adrenal physiology and disease. Therefore, the main objective of the study was to evaluate the effect of luteinizing hormone (LH) signaling and selenium (Se2+) exposure on androgen adrenal signaling via canonical androgen receptor (AR), and membrane androgen receptor acting as zinc transporter (zinc- and iron-like protein 9; ZIP9). For herein evaluations, adrenals isolated from transgenic mice with elevated LH receptor signaling (KiLHRD582G) and adrenals obtained from rabbits used for ex vivo adenal cortex culture and exposure to Se2+ were utilized. Tissues were assessed for morphological, morphometric, and Western blot analyses and testosterone and zinc level measurements.Comparison of adrenal cortex histology and morphometric analysis in KiLHRD582G mice and Se2+-treated rabbits revealed cell hypertrophy. No changes in the expression of proliferating cell nuclear antigen (PCNA) were found. In addition, AR expression was decreased (p < 0.001) in both KiLHRD582G mouse and Se2+-treated rabbit adrenal cortex while expression of ZIP9 showed diverse changes. Its expression was increased (P < 0.001) in KiLHRD582G mice and decreased (P < 0.001) in Se2+-treated rabbits but only at the dose 10 ug/100 mg/ tissue. Moreover, increased testosterone levels (P < 0.05) and zinc levels were detected in the adrenal cortex of KiLHRD582G mice whereas in rabbit adrenal cortex treated with Se2+, the effect was the opposite (P < 0.001).

Aberrant crypt foci are regionally affected by zinc treatment in a 1,2-dimethylhydrazine induced colon carcinogenesis model

Zinc is a trace element widely known for its marked antioxidant properties. To gain more insight into the site- and time- specific mechanisms by which it induces chemoprevention, this study was elaborated over a pre-cancerous model of colon carcinogenesis. Colon cancer was induced by 1,2-dimethylhydrazine (DMH) in mice (20 mg/kg for 2 weeks) and groups of animals were supplemented with or without zinc sulfate (ZnSO₄, 200 mg/L) in drinking water for 4, 10 or 14 weeks. Colon tissues were collected for pathological observation, analyzing aberrant crypt (AC) and aberrant crypt foci (ACF) formations, multiplicity and distribution. Similarly, histological assessment and mucin production, as well as oxidative stress markers estimation was performed for the different groups. Results showed a significant increase in ACF and AC numbers, ACF multiplicity and demonstrated stronger distal occurrence than in the proximal after DHM administration. Histopathological analysis presented marked structural alterations and mucin loss in the distal than the proximal colons. A significant increase in myeloperoxidase (MPO), nitric oxide (NO), L-ornithine and malondialdehyde (MDA) levels was observed followed by a significant decrease in antioxidant markers (superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH)). Oral ZnSO₄ supplementation (continuous or partial) induced significant decrease in ACF, AC numbers and multiplicity, restored histological architecture and mucin production, and a significant decrease in proinflammatory markers while it reduced antioxidants to normal levels. From this study, insight was obtained on the use of ZnSO₄ as a chemopreventive agent and shed light on its potential, as a supplement in nutraceutical approaches.

MAPRE1 as a plasma biomarker for early-stage colorectal cancer and adenomas

Blood-based biomarkers for early detection of colorectal cancer could complement current approaches to colorectal cancer screening. We previously identified the APC-binding protein MAPRE1 as a potential colorectal cancer biomarker. Here, we undertook a case-control validation study to determine the performance of MAPRE1 in detecting early colorectal cancer and colon adenoma and to assess the potential relevance of additional biomarker candidates. We analyzed plasma samples from 60 patients with adenomas, 30 with early colorectal cancer, 30 with advanced colorectal cancer, and 60 healthy controls. MAPRE1 and a set of 21 proteins with potential biomarker utility were assayed using high-density antibody arrays, and carcinoembryonic antigen (CEA) was assayed using ELISA. The biologic significance of the candidate biomarkers was also assessed in colorectal cancer mouse models. Plasma MAPRE1 levels were significantly elevated in both patients with adenomas and patients with colorectal cancer compared with controls (P < 0.0001). MAPRE1 and CEA together yielded an area under the curve of 0.793 and a sensitivity of 0.400 at 95% specificity for differentiating early colorectal cancer from controls. Three other biomarkers (AK1, CLIC1, and SOD1) were significantly increased in both adenoma and early colorectal cancer patient plasma samples and in plasma from colorectal cancer mouse models at preclinical stages compared with controls. The combination of MAPRE1, CEA, and AK1 yielded sensitivities of 0.483 and 0.533 at 90% specificity and sensitivities of 0.350 and 0.467 at 95% specificity for differentiating adenoma and early colorectal cancer, respectively, from healthy controls. These findings suggest that MAPRE1 can contribute to the detection of early-stage colorectal cancer and adenomas together with other biomarkers.

Lack of protective effects of zinc gluconate against rat colon carcinogenesis

Zinc has been proposed as a promising chemopreventive candidate against colon cancer. However, few studies on the potential beneficial effects of this trace element on cancer chemoprevention are available. The present study was designed to investigate the potential modifying influence of zinc gluconate (ZnGly) on the initiation step of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH). Male Wistar rats received orally ZnGly (15 mg elemental zinc/kg, 3 times per wk) 2 wk before and during DMH treatment (3 × 40 mg/kg, once a wk). The animals were euthanized at the end of 4th and 16th wk. Colons were analyzed for aberrant crypt foci (ACF) and tumor development. Blood and colon zinc levels, cell proliferation, and apoptosis indexes in colonic crypts were analyzed 24 h after the last DMH administration. Oral treatment with ZnGly did neither alter the number of ACF nor the indexes of cell proliferation and apoptosis in the colonic mucosa. The incidence and multiplicity of colon tumors induced by DMH and their histopathological patterns were not modified by previous treatment with ZnGly. These findings indicate a lack of chemopreventive action of zinc gluconate supplementation on the initiation step of rat colon carcinogenesis induced by DMH.

Detection of Cu(I) and Zn(II) ions in colon tissues by multi-photon microscopy: novel marker of antioxidant status of colon neoplasm

Aims

Establishing probe-based analysis is important for developing multi-photon microscopy (MPM) to make an early diagnosis of colon neoplasm and assess its antioxidant status. Cu(I) and Zn(II) ions are trace elements which roll as cofactors of antioxidant, superoxide dismutase. However, there have been no reports on the features of MPM image using probe of Cu(I) and Zn(II) ions. Our main objective in this study was application of newly developed multi-photon probe (MP) probe on Cu(I) and Zn(II) ions as a tool to assess antioxidative status of colon neoplasm.

Methods

This study was a pilot study. Colon cancer cell lines (ACT116 and HT-29), NIH3T3 cells and tissues of normal colon mucosa and colon neoplasm obtained during colonoscopic biopsy from 17 patients were stained with MP probes for Cu(I) and Zn(II) (ACu1 and AZn1). Cu(I)/Zn(II) levels in the cells and tissues were determined by detecting MP-excited fluorescence by MPM.

Results

MPM images of cells stained with MP probes revealed that Cu(I) was more abundant in ACT116 and HT-29 cells than in NIH3T3 cells, while Zn(II) was more abundant in NIH3T3 cells than in ACT116 and HT-29 cells. Normal tissues had a defined texture, whereas adenoma/adenocarcinoma tissues were amorphous. The level of Cu(I) increased and that of Zn(II) decreased with the transition from normal to adenoma to adenocarcinoma tissue.

Conclusion

MPM can be used to determine the relative Cu(I)/Zn(II) levels in cells and colon tissues by using ACu1 and AZn1 as MPM probes. These finding are new research tools for gastroenterologists to assess antioxidant status of colon neoplasm.

Impact of inorganic nutrients on maintenance of genomic stability

Maintenance of genome stability is of fundamental importance for counteracting carcinogenesis. Many human genome instability syndromes exhibit a predisposition to cancer. An increasing body of epidemiological evidence has suggested a link between nutrient status and risk of cancer. Like other chemicals, nutrients can be toxic when consumed in excess. It has become clear that both nutritional deficiency and toxicity can compromise the integrity of the genome. This article focuses on roles of inorganic trace nutrients, including selenium, copper, zinc, and iron, in the redox regulation of genome stability and how they relate to the pathologies of genomic instability syndromes and cancer.

Unsymmetrical DMH - an isomer of 1,2 DMH - is it potent to induce gastrointestinal carcinoma in rats?

Very few animal studies have used 1,1-dimethyl hydrazine (unsymmetrical dimethyl hydrazine - UDMH) as a carcinogen. This study was designed to investigate the carcinogenicity of UDMH in the gastrointestinal tract in a rat model. We wanted to observe if there were any changes in tissue zinc levels and tissue copper zinc superoxide dismutase (CuZnSOD) enzyme activity during the carcinogenic process, and to compare these values with those of control rats in the medium- and long-term. Six-week-old Wistar rats were given a subcutaneous injection of UDMH (30mg/kg body wt) twice a week for 20 weeks, and sacrificed after 5 and 9 months of treatment. Tissue zinc levels showed a significant decrease (p<0.05) in the large intestine at 9 months, whereas in the stomach and small intestine there were no significant changes at 5 and 9 months. Tissue CuZnSOD enzyme activity in the stomach, small intestine and large intestine showed no significant decrease at 5 and 9 months as compared to controls. Histologically, the large intestine was normal at 9 months. This study suggests that UDMH administered at the above dosage was not carcinogenic in this model.