Lack of chemoprevention of dietary Agaricus blazei against rat colonic aberrant crypt foci

Abstract

<jats:p> The mushroom Agaricus blazei ( Ab) has been widely used in folk medicine to treat various diseases including cancer. No information is available on its possible protective effects on the development of colon cancer. The potential blocking effect of Ab intake on the initiation stage of colon carcinogenesis was investigated in a short-term (4-week) bioassay using aberrant crypt foci (ACF) as biomarker. Male Wistar rats were given four subcutaneous injections of the carcinogen 1,2-dimethylhydrazine (DMH, 40 mg/kg bw, twice a week), during 2 weeks to induce ACF. The diet containing Ab at 5% was given 2 weeks before and during carcinogen treatment to investigate the potential beneficial effects of this edible mushroom on DMH-induced ACF. All groups were killed at the end of the fourth week. The colons were analyzed for ACF formation in 1% methylene blue whole-mount preparations and for cell proliferation in histological sections immunohistochemically stained for the proliferating cell nuclear antigen (PCNA). All DMH-treated rats developed ACF mainly in the middle and distal colon. Agaricus blazei intake at 5% did not alter the number of ACF induced by DMH or the PCNA indices in the colonic mucosa. Thus, the results of the present study did not confirm a chemopreventive activity of Ab on the initiation stage of rat colon carcinogenesis. </jats:p>

Lack of Protective Effects of Zinc Gluconate against Rat Colon Carcinogenesis

“…Also, DMH can be metabolized to a methyl free radical and generate hydroxyl radical or hydrogen peroxide in the presence of essential metallic trace elements, which may contribute to the initiation of lipid peroxidation and DNA damage in the colon (46). In the present study, the short-term treatment with DMH, induced a pronounced injury in the colonic mucosa, as confirmed by high apoptosis indexes 24 h after the last carcinogen administration, as previously described by others (29,47). However, ZnGly supplementation before and during the initiation step of colon carcinogenesis did not show a protective effect against DMH-induced cytotoxicity.…”

ER-Mitochondria Calcium Flux by β-Sitosterol Promotes Cell Death in Ovarian Cancer

“…The differentiation ability of the human cancer cells A549 is decreased by β-sitosterol, which also induces G0/G1 cell cycle arrest, decreased CDK4 and cyclin D1 levels, and increased expression of p21/Cip1 and p27/Kip1 [27]. In colon cancer, β-sitosterol decreases the expression of proliferating cell nuclear antigen (PCNA), which is known as an indicator of cells' proliferative activity [28,29]. Similarly, in our experiments, β-sitosterol inhibited the proliferation of human ovarian cancer cells ES2 and OV90.…”

The role of edible mushrooms in health: Evaluation of the evidence

“…The mechanism of this effect is possibly via action of PSK on a toll-like receptor initiating a signaling cascade involving T helper 1 cells which induce IL-2 and IFN-c and then activate natural killer cells. This sequence of signaling cascades has recently been described in the modulation of innate immunity of Agaricus blazei (Ab) (Hetland et al, 2011), although intake of 5% Ab over 4 weeks by male Wistar rats did not confirm chemopreventive activity on the initiation stage of rat colon carcinogenesis (Ziliotto, Barbisan, & Rodrigues, 2008;Ziliotto, Pinheiro, Barbisan, & Rodrigues, 2009).…”