8-hydroxy-2--deoxyguanosine and Adenomatous-Polyps

Brazilian propolis, a folk medicine, is used worldwide as an alternative medicine to prevent colon cancer. The objective of the study was to test in a small pilot biomarker study in a high-risk group the safety and efficacy of propolis for colon cancer prevention, which has not been evaluated in humans.. Subjects with adenoma polyps recently removed from the colon were randomly assigned to a propolis group of 15 and a placebo group of 16. In a double-blind study, the propolis group received capsules containing 165 μmol artepillin C and 150 μmol other polyphenols per day for 3 months. Prior to and at the end of the experiments, their blood was analyzed using biochemical tests, and specimens from the normal-appearing sigmoid colon mucosa were biopsied endoscopically to examine the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and mRNA expressions of proliferating cell nuclear antigen, cyclin D1, and Bax.. Propolis extract significantly increased the mRNA level of cyclin D1 in the sigmoid colon mucosa, and the other biomarkers remained unchanged. Blood biochemical tests showed significantly higher activity of creatine phosphokinase (CPK), 143 ± 52 units/ml in the propolis group and 104 ± 38 units/ml in the placebo group (p = 0.026), at the end of the study. The increase in CPK activity in the propolis group was due to the increase of the myocardial band form of CPK. On the other hand, laxative treatment prior to endoscopic biopsy significantly increased 8-OHdG levels.. The results from our pilot study did not provide evidence that Brazilian propolis was effective in preventing changes occurring during early stages of colon cancer. In contrast, propolis may have detrimental side effects on muscle tissue, including myocardial cells.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adenomatous Polyps; Aged; Biomarkers; Brazil; Colon; Colorectal Neoplasms; Creatine Kinase; Cyclin D1; Deoxyguanosine; Double-Blind Method; Female; Humans; Intestinal Polyps; Male; Middle Aged; Phenylpropionates; Pilot Projects; Plant Extracts; Polyphenols; Proliferating Cell Nuclear Antigen; Propolis; RNA, Messenger

Oxidative stress is involved in the pathogenesis of colon cancer. We wanted to elucidate at which stage of the disease this phenomenon occurs. In the examined groups of patients with colorectal cancer (CRC, n = 89), benign adenoma (AD, n = 77) and healthy volunteers (controls, n = 99), we measured: vitamins A, C and E in blood plasma, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanine (8-oxoGua) in leukocytes and urine, leukocyte 8-oxoGua excision activity, mRNA levels of APE1, OGG1, 8-oxo-7,8-dihydrodeoxyguanosine 5'-triphosphate pyrophosphohydrolase (MTH1) and OGG1 polymorphism. The vitamin levels decreased gradually in AD and CRC patients. 8-OxodG increased in leukocytes and urine of CRC and AD patients. 8-OxoGua was higher only in the urine of CRC patients. 8-OxoGua excision was higher in CRC patients than in controls, in spite of higher frequency of the OGG1 Cys326Cys genotype, encoding a glycosylase with decreased activity. mRNA levels of OGG1 and APE1 increased in CRC and AD patients, which could explain increased 8-oxoGua excision rate in CRC patients. MTH1 mRNA was also higher in CRC patients. The results suggest that oxidative stress occurs in CRC and AD individuals. This is accompanied by increased transcription of DNA repair genes, and increased 8-oxoGua excision rate in CRC patients, which is, however, insufficient to counteract the increased DNA damage.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adenoma; Adenomatous Polyps; Adult; Aged; Aging; Antioxidants; Carcinoma; Case-Control Studies; Colonic Neoplasms; Deoxyguanosine; DNA Glycosylases; DNA Repair; DNA Repair Enzymes; DNA-(Apurinic or Apyrimidinic Site) Lyase; DNA, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Middle Aged; Neoplasm Staging; Oxidative Stress; Phosphoric Monoester Hydrolases; Polymorphism, Single Nucleotide; RNA, Messenger; Sex Characteristics; Smoking