Lack of cyclin D1 overexpression in gastric carcinogenesis

Astaxanthin Inhibits Helicobacter pylori-induced Inflammatory and Oncogenic Responses in Gastric Mucosal Tissues of Mice

Helicobacter pylori is recognized as a risk factor for gastric carcinogenesis. The chronic exposure of gastric epithelium to H. pylori induces a prolonged inflammatory state that may progress to gastric cancer. Astaxanthin, a pinkish antioxidant carotenoid, abundant in marine organisms, is known for its protective effect against inflammation and multiple types of cancer. The purpose of this study was to examine the effect of astaxanthin on H. pylori-induced oxidative injury, inflammation, and oncogene expression in gastric mucosal tissues of the infected mice. Mice were inoculated using oral gavage with H. pylori suspension (10⁸ colony forming unit of H. pylori/0.1 mL) for three days, after which they were fed astaxanthin-supplemented diet (5 mg/kg body weight/day for seven weeks). The effects of astaxanthin on H. pylori-induced increase in lipid peroxide (LPO) production, myeloperoxidase (MPO) activity, expression of the inflammatory cytokine IFN-_γ and oncogenes (c-myc and cyclin D1), and the accompanying histologic changes in gastric mucosal tissues were evaluated. H. pylori infection increased the level of LPO, MPO activity, and the expression of IFN-_γ, c-myc, and cyclin D1 in gastric mucosal tissues of mice. H. pylori infection induced neutrophil infiltration and hyperplasia of gastric mucosa. Astaxanthin supplementation attenuated these effects. In conclusion, consumption of astaxanthin-rich foods may prevent H. pylori-associated oxidative damage and inflammatory and oncogenic responses in gastric mucosal tissues.

Hath1 inhibits proliferation of colon cancer cells probably through up-regulating expression of Muc2 and p27 and down-regulating expression of cyclin D1

Previous studies showed that Math1 homologous to human Hath1 can cause mouse goblet cells to differentiate. In this context it is important that the majority of colon cancers have few goblet cells. In the present study, the potential role of Hath1 in colon carcinogenesis was investigated. Sections of paraffin-embedded tissues were used to investigate the goblet cell population of normal colon mucosa, mucosa adjacent colon cancer and colon cancer samples from 48 patients. Hath1 and Muc2 expression in these samples were tested by immunohistochemistry, quantitative real-time reverse transcription -PCR and Western blotting. After the recombinant plasmid, pcDNA3.1(+)-Hath1 had been transfected into HT29 colon cancer cells, three clones were selected randomly to test the levels of Hath1 mRNA, Muc2 mRNA, Hath1, Muc2, cyclin D1 and p27 by quantitative real-time reverse transcription-PCR and Western blotting. Moreover, the proliferative ability of HT29 cells introduced with Hath1 was assessed by means of colony formation assay and xenografting. Expression of Hath1, Muc2, cyclin D1 and p27 in the xenograft tumors was also detected by Western blotting. No goblet cells were to be found in colon cancer and levels of Hath1 mRNA and Hath1, Muc2 mRNA and Muc2 were significantly down-regulated. Hath1 could decrease cyclin D1, increase p27 and Muc2 in HT29 cells and inhibit their proliferation. Hath1 may be an anti-oncogene in colon carcinogenesis.

Expression of p53, VEGF, microvessel density, and cyclin-D1 in noncancerous tissue of inflammatory bowel disease

We aimed to evaluate the carcinogenesis risk in inflammatory bowel disease via p53 mutation and its relation with hyperproliferation (cyclin-D1) and angiogenesis (with vascular endothelial growth factor [VEGF] and microvessel density) and whether these events play important roles in pathogenesis of inflammatory bowel disease. Colonic tissue samples of 26 ulcerative colitis, 6 Crohn's disease, and 8 amoebic colitis patients as well as samples of 10 healthy controls were stained with p53, cyclin-D1, CD34, and VEGF monoclonal antibodies by immunohistochemistry and evaluated semiquantitatively. Expression of p53 was higher in ulcerative colitis than in the healthy control and amoebic colitis groups (4.15 +/- 2.07, 1.4 +/- 1.5, 1.3 +/- 1.5; P < 0.001). The Crohn's disease group had the highest p53 expression (4.6 +/- 1.6). The Crohn's disease, ulcerative colitis, and amoebic colitis groups all had higher VEGF expression than did the healthy controls (respectively, 4.3 +/- 1.2, 2.92 +/- 2.0, 2.3 +/- 1.5, 0.6 +/- 0.97; P < 0.001). Also, microvessel density was statistically higher in all three colitis groups than in healthy controls. Cyclin-D1 expression in all four groups was similar. The study showed that p53 mutation was present in nonneoplastic mucosa of inflammatory bowel disease patients. Detecting strong p53 overexpression with VEGF overexpression may help in differentiating inflammatory bowel disease from other colitis.

Immunohistochemical expression of cell-cycle proteins in gastric precancerous lesions

BACKGROUND

The early indicator for the subject predisposed to gastric cancer is abnormal proliferation of gastric epithelial cells, such as atrophic gastritis (AG), intestinal metaplasia (IM), and dysplasia, which have been considered as precancerous lesions of gastric cancer. To determine whether p53 protein, cyclins D1, and D3, and p27(kip1) play a role in the carcinogenesis pathway of gastric cancer, we performed an immunohistochemical study of their expression in gastric precancerous lesions.

METHODS

A total of 1 45 endoscopic gastric biopsy specimens of AG, IM, and gastric dysplasia were studied. These molecular markers were localized by immunohistochemistry.

RESULTS

P53 was expressed in 15% of cases with gastric dysplasia and not in the pre-dysplastic stages of the gastric mucosa. All cases were concerning high-grade dysplasia. Cyclin D1 protein was almost undetectable in the precancerous lesions of gastric cancer. Cyclin D3 protein overexpression was seen in 10% of biopsies with IM, and 50% of biopsies with gastric dysplasia. High expression of p27(kip1) protein was demonstrated in all cases of chronic gastritis. As atrophy, IM, and dysplasia develop, expression of p27(kip1) protein is suppressed. In total, 15% of dysplastic cases showed no expression of p27(kip1) protein.

CONCLUSIONS

(i) P53 mutation must be a late event during the development of gastric cancer. (ii) Cyclin D1 protein overexpression may not play a role in the progression from normal to neoplastic gastric mucosa, while overexpression of cyclin D3 is an earlier event during gastric carcinogenesis, and its role must be further evaluated. (iii) Reduced expression of p27(kip1) is a rather early event in gastric tumorigenesis, before dysplastic changes occur.

Immunohistochemical prognostic indicators of gastrointestinal carcinoid tumours

AIMS

The aim of this study was to determine whether expression of the oncoproteins p21, p53, E-cadherin (EC), cyclin D1, bcl-2 and Rb and the proliferation marker Ki-67 is predictive of malignant behaviour in gastrointestinal carcinoid tumours.

METHODS

Immunohistochemical (IHC) staining was performed on carcinoid tumours from 41 patients (31 rectal, eight gastrointestinal, two appendiceal lesions). The six tumours that had invaded deeply into the muscularis propria or beyond, had metastasized to regional lymph nodes or had metastasized to a distant site were classified as the malignant group, and the other 35 tumours formed the benign group. IHC expression was compared between the two groups, and the prognostic value of each marker was assessed.

RESULTS

Of the six tumours in the malignant group, 66.7% were p21 positive, 0% were p53 positive, 33.3% were EC positive, 100% were cyclin D1 positive, 33.3% were Rb positive, 16.7% were bcl-2 positive and 50% were Ki-67 positive. Of the 35 tumours in the benign group, 17.1% were p21 positive, 0% were p53 positive, 100% were EC positive, 94.3% were cyclin D1 positive, 8.6% were Rb positive, 17.1% were bcl-2 positive and 0% were Ki-67 positive.

CONCLUSIONS

These data show that p53, cyclin D1, Rb, bcl-2 and Ki-67 staining does not correlate with malignant behaviour but that overexpression of p21 (P=0.02) and reduced staining of EC (P=0.005) do correlate with malignant behaviour. These two parameters may therefore be useful as prognostic indicators for gastrointestinal carcinoid tumours.