Azoxymethane induced colon tumors

There is some evidence to suggest that soluble compounds produced by lactic acid bacteria may act directly on tumor cells to inhibit their growth. Arimochi et al. (1997) showed (a) an inhibitory effect of L. acidophilus on azoxymethane-induced ACF formation in rat colon and (b) enhanced removal of 0 -methylguanine from the colonic mucosal DNA. This inhibitory effect was found in culture supernatants and not from bacterial cells. Furthermore, other studies have shown that dietary administration of lyophilized cultures of B. longum suppressed azoxymethane-induced colonic tumor development, along with a decrease in colonic mucosal cell proliferation and colonic mucosal and tumor ornithine decarboxylase and ras-p21 activities (Reddy, 1998). 

Chaurand, R, DaGue, B.B., Pearsall, R.S., Threadgill, D.W. and Caprioli, R.M., Profiling proteins from azoxymethane-induced colon tumors at the molecular level by matrix-assisted laser desorption/ionization mass spectrometry. Proteomics, 1, 1320-1326 (2001). 

Colon-1 Inhibition of azoxymethane (AOM) induced colon tumors... 

Inhibition of azoxymethane (AOM) induced colon tumors Inhibition of Af-methyl-A -nitrosourea (NMU) induced colon tumors Inhibition ofiV-diethylnitrosamine (DEN)/phenobarbital (PB) induced hepatic tumors Inhibition of sponateneous hepatoma development in C3H/HeNCrj mice Inhibition of 4-(methylnitrosoamino)-l-(3-pyridyl)-I-butanone (NNK) induced lung tumors Inhibition of 4-nitroquinoline-W-oxide (4-NQO)/glycerol induced pulmonaiy tumors Inhibition of NMU induced mammary tumors... 

Reddy, B. S. Maeura, Y. (1984). Tumor promotion by dietary fat in azoxymethane-induced colon carcinogenesis in female F344 rats influence of amount and source of dietary fat. J. Natl Cancer Inst, 72(3), 745-50. 

VERGHESE M, RAO D R, CHAWAN C B, WILLIAMS L L, SHACKELFORD L (2002) Dietary inului suppresses azoxymethane-induced aberrant crypt foci and colon tumors at the promotion stage in young fisher 344 rats. J. Nutr. 132 2809-2813. 

Selective COX-2 inhibitors have also been shown to prevent early and late forms of colorectal neoplasia in rat models. Reddy et al. showed that administration of celecoxib inhibited aberrant colonic crypt foci (ACF) induction and multiplicity by about 40-49% in an azoxymethane-induced ACF rat model (81). Later the same investigators also showed that dietary administration of celecoxib can inhibit both the incidence and multiplicity of colon tumors by about 93 % and 97 %, respectively in the same rat model (82). Other researchers reported similar results with the Min mouse model (52). There is little data on human clinical trials with selective COX-2 inhibitors for colorectal tumor prevention. Recently Steinbach et al. conducted a double-blind, placebo-controlled study with 77 patients with FAP, and reported that treatment with celecoxib, a selective COX-2 inhibitor, for 6 mo led to a significant reduction (28%) in the number of colorectal polyps in these patients (50). Collectively, COX-2 nonspecific or specific NSAIDs appear to have chemopreventive activity against colorectal cancer development. Selective... 

Takahashi, M., Eukuda, K., Ohata, T., Sugimura, T., and Wakadayashi, K., Increased expression of inducible and endothelial constitutive nitric oxide synthase in rat colon tumors induced by azoxymethane. Cancer Res., 57, 1233, 1997. 

Inhibitory Effects of Oral Administration of an Extract of Orange Peel in the Diet on Azoxymethane-Induced Formation of Aberrant Crypt Foci and Colon Tumor in CF-1 Mice... 

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