Comparative Immunohistochemical Analysis of Ochratoxin A Tumourigenesis in Rats and Urinary Tract Carcinoma in Humans; Mechanistic Significance of p-S6 Ribosomal Protein Expression
Ochratoxin A (OTA) is considered to be a possible human urinary tract carcinogen, based largely on a rat model, but no molecular genetic changes in the rat carcinomas have yet been defined. The phosphorylated-S6 ribosomal protein is a marker indicating activity of the mammalian target of rapamycin, which is a serine/threonine kinase with a key role in protein biosynthesis, cell proliferation, transcription, cellular metabolism and apoptosis, while being functionally deregulated in cancer. To assess p-S6 expression we performed immunohistochemistry on formalin-fixed and paraffin-embedded tumours and normal tissues. Marked intensity of p-S6 expression was observed in highly proliferative regions of rat renal carcinomas and a rare angiosarcoma, all of which were attributed to prolonged exposure to dietary OTA. Only very small OTA-generated renal adenomas were negative for p-S6. Examples of rat subcutaneous fibrosarcoma and testicular seminoma, as well as of normal renal tissue, showed no or very weak positive staining. In contrast to the animal model, human renal cell carcinoma, upper urinary tract transitional cell carcinoma from cases of Balkan endemic nephropathy, and a human angiosarcoma were negative for p-S6. The combined findings are reminiscent of constitutive changes in the rat tuberous sclerosis gene complex in the Eker strain correlated with renal neoplasms, Therefore rat renal carcinogenesis caused by OTA does not obviously mimic human urinary tract tumourigenesis.
References
[1]
Krogh, P. Porcine Nephropathy Associated with Ochratoxin A. In Mycotoxinsand Animal Foods; Smith, J.E., Henderson, R.S., Eds.; CRC Press: Boca Raton, FL, USA, 1991; pp. 627–645.
[2]
The European Food Safety Authority. Opinion of the scientific panel on contaminants in the food chain on a request from the Commission related to ochratoxin A in Food. EFSA J. 2006, 365, 1–56.
[3]
Boorman, G.A. Toxicology and Carcinogenesis Studies of Ochratoxin A (CAS No. 303-47-9) in F344/N Rats (Gavage Studies); Technical Report 358; Research Triangle Park: Research Triangle region, NC, USA, 1989.
[4]
Castegnaro, M.; Mohr, U.; Pfohl-Leszkowicz, A.; Esteve, J.; Steinmann, J.; Tillmann, T.; Michelon, J.; Bartsch, H. Sex- and strain-specific induction of renal tumors by ochratoxin A in rats correlates with DNA adduction. Int. J. Cancer 1998, 77, 70–75, doi:10.1002/(SICI)1097-0215(19980703)77:1<70::AID-IJC12>3.0.CO;2-D.
[5]
Bendele, A.M.; Carlton, W.W.; Krogh, P.; Lillehoi, E.B. Ochratoxin A carcinogenesis in the (C57BL/6J x C3H) F1 mouse. J. Natl. Cancer Inst. 1985, 75, 733–744.
[6]
Mantle, P.; Kulinskaya, E.; Nestler, S. Renal tumourigenesis in male rats in response to chronic dietary ochratoxin A. Food Addit. Contam. 2005, 22, 58–64, doi:10.1080/02652030500358431.
[7]
Maher, E.R. Identification of the Individual at Risk: The Molecular and Clinical Genetics of Renal Cell Carcinoma. In The Effective Management of Renal Cell Carcinoma; Aitchison, M., Oliver, R.T.D., Miles, A., Eds.; Aesculapius Medical Press: London, UK, 2004; pp. 19–28.
[8]
Mantle, P.G. Minimum tolerable exposure period and maximum threshold dietary intake of ochratoxin A for causing renal cancer in male Dark Agouti rats. Food Chem. Toxicol. 2009, 47, 2419–2424, doi:10.1016/j.fct.2009.05.043.
[9]
Mantle, P.G.; Amerasinghe, C.; Brown, A.L.; Herman, D.; Horn, T.; Krogh, T.; Odell, E.W.; Rosenbaum, T.; Tatu, C.A. A pilot study of nuclear instability in archived renal and upper urinary tract tumours with putative ochratoxin aetiology. Toxins 2010, 2, 326–340, doi:10.3390/toxins2030326.
[10]
Mantle, P.G.; Dobrota, M.; Gillett, C.E.; Odell, E.W.; Pinder, S.E. Oncological outcomes in rats given nephrocarcinogenic exposure to dietary ochratoxin A, followed by the tumour promoter sodium barbital for life: a pilot study. Toxins 2010, 2, 552–571, doi:10.3390/toxins2040552.
[11]
Mantle, P.G.; Nolan, C.C. Pathological outcomes in kidney and brain in male Fischer rats given dietary ochratoxin A, commencing at one year of age. Toxins 2010, 2, 1100–1110, doi:10.3390/toxins2051100.
[12]
Mantle, P.; Kulinskaya, E. Lifetime, low-dose ochratoxin A, dietary study on renal carcinogenesis in male Fischer rats. Food Add. Contam. 2010, 27, 1566–1573, doi:10.1080/19440049.2010.502302.
[13]
Maher, E.R.; Ricketts, C.J. personal communication. University of Birmingham: UK, 2012.
[14]
Hasumi, Y.; Baba, M.; Ajima, R.; Hasumi, H.; Valera, V.A.; Klein, M.E.; Haines, D.C.; Merino, M.J.; Hong, S.-B.; Yamaguchi, T.P.; et al. Homozygous loss of BDH causes early embryonic lethality and kidney tumor development with activation of mTORC1 and mTORC2. Proc. Natl. Acad. Sci. USA 2009, 106, 18722–18727.
[15]
McDorman, K.S.; Wolf, D.C. Use of the spontaneous Tsc2 knockout (Eker) rat model of hereditary renal cell carcinoma for the study of renal carcinogens. Toxicol. Pathol. 2002, 30, 675–680, doi:10.1080/01926230290168542.
[16]
Ruggero, D.; Pandolfi, P.P. Does the ribosome translate cancer? Nat. Rev. Cancer 2003, 3, 179–192, doi:10.1038/nrc1015.
[17]
Kasprzak, K.S.; Diwan, B.A.; Knonishi, N.; Misra, M.; Rice, J.M. Initiation by nickel(11) acetate and promotion by sodium barbital of renal cortical epithelial tumours in male F344 rats. Carcinogenesis 1990, 11, 647–652, doi:10.1093/carcin/11.4.647.
[18]
Brown, A.L.; Odell, E.W.; Mantle, P.G. DNA ploidy distribution in renal tumours induced in male rats by dietary ochratoxin A. Exp. Toxicol. Pathol. 2007, 59, 85–95, doi:10.1016/j.etp.2007.05.001.
[19]
Wilson, C.; Bonnet, C.; Guy, C.; Idziaszczyk, S.; Colley, J.; Humphreys, V.; Maynard, J.; Sampson, J.R.; Cheadle, J.P. Tsc1 haploinsufficiency without mammalian target of rapamycin activation is sufficient for renal cyst formation in Tsc1+/？ mice. Cancer Res. 2006, 66, 7934–7938.
[20]
Kenerson, H.L.; Aicher, L.D.; True, L.D.; Yeung, R.S. Activated mammalian target of rapamycin pathway in the pathogenesis of tuberous sclerosis complex renal tumours. Cancer Res. 2002, 62, 5645–5650.
[21]
Iwenofu, O.H.; Lackman, R.D.; Staddon, A.P.; Goodwin, D.G.; Haupt, H.M.; Brooks, J.S. Phospho-S6 ribosomal protein: A potential new predictive sarcoma marker for targeted mTOR therapy. Modern Pathol. 2008, 21, 231–237, doi:10.1038/modpathol.3800995.
[22]
Stemmer, K.; Ellinger-Ziegelbauer, H.; Ahr, H.J.; Dietrich, D.R. Carcinogen-specific gene expression profiles in short-term treated Eker and wild-type rats indicative of pathways involved in renal tumourigenesis. Cancer Res. 2007, 67, 4052–4068, doi:10.1158/0008-5472.CAN-06-3587.
[23]
Mally, A.; Dekant, W. Mycotoxins and the kidney: modes of action for renal tumor formation by ochratoxin A in rodents. Mol. Nutr. Food Res. 2009, 53, 467–478, doi:10.1002/mnfr.200800149.
[24]
Czakai, K.; Muller, K.; Mosesso, P.; Pepe, G.; Schulz, M.; Gohla, A.; Patnaik, D.; Dekant, W.; Higgins, J.M.G.; Mally, A. Perturbation of mitosis through inhibition of histone acetyltransferases: The key to ochratoxin toxicity and carcinogenicity? Toxicol. Sci. 2011, 122, 317–329, doi:10.1093/toxsci/kfr110.
[25]
Mantle, P.G.; Faucet-Marquis, V.; Manderville, R.A.; Squillaci, B.; Pfohl-Leszkowicz, A. Structures of covalent adducts between DNA and ochratoxin A: A new factor in debate about genotoxicity and human risk assessment. Chem. Res. Toxicol. 2010, 23, 89–98, doi:10.1021/tx900295a.
[26]
Pfohl-Leszkiwicz, A.; Faucet-Marquis, V.; Tozlovanu, M.; Peraica, M.; Stefanovic, V.; Manderville, R. C8-2′-Deoxyguanosine ochratoxin A-adducts and OTA metabolites in biologic fluids as biomarkers of OTA exposure. In Proceedings of MycoRed International Conference, Mendoza, Argentina, 15–17 November 2011; p. 90.
[27]
Jennings-Gee, J.E.; Tozlovanu, M.; Manderville, R.; Miller, M.S.; Pfohl-Leszkowicz, A.; Schwartz, G.G. Ochratoxin A: In utero exposure in mice induces adducts in testicular DNA. Toxins 2010, 2, 1428–1444, doi:10.3390/toxins2061428.
[28]
Mantle, P.G. Comments on “Ochratoxin A: In utero exposure in mice induces adducts in testicular DNA. Toxins 2010, 2, 1428–1424”—Mis-citation of rat literature to justify a hypothetical role for ochratoxin A in testicular cancer. Toxins 2010, 2, 2333–2336.
[29]
Arai, M.; Hibino, T. Tumorgenicity of citrinin in male F344 rats. Cancer Lett. 1983, 17, 281–287, doi:10.1016/0304-3835(83)90165-9.
[30]
The European Food Safety Authority. Scientific opinion on the risks for public and animal health related to the presence of citrinin in food and feed. EFSA J. 2012, 10, 2605.
[31]
Mantle, P.G.; McHugh, K.M.; Fincham, J.E. Contrasting nephropathic responses to oral administration of extract of cultured Penicillium polonicum in rat and primate. Toxins 2010, 2, 2082–2097.
[32]
Mantle, P.G. Renal histopathological responses to nephrotoxic Penicillium aurantiogriseum in the rat during pregnancy, lactation and after weaning. Nephron 1994, 66, 93–98, doi:10.1159/000187773.
