ABSTRACT
Tumor necrosis factor-alpha (TNF-α) is a proinflammatory cytokine that has been linked to breast cancer development. Estrogen metabolic pathway is also involved in breast carcinogenesis and DNA adducts formation. In this study we investigated the effect of TNF-α on the estrogen metabolic pathway in MCF-7, a breast cancer cell line. Capillary liquid chromatography/mass spectrometry (LC/MS) and High performance liquid chromatography (HPLC) were used for analysis of estrogen metabolites and estrogen-DNA adducts levels respectively. Reporter gene assay, Real time reverse transcription polymerase chain reaction (real time RT-PCR) and Western blot were used to assess the expression of estrogen metabolizing genes and enzymes. TNF-α significantly increased the total EM and decreased the estrone (E1) / 17-ß estradiol (E2) ratio. Moreover, it altered the expression of genes and enzymes involved in E2 activation and deactivation pathways e.g. Cytochrome P-450 1A1 (CYP1A1), Cytochrome P-450 1B1 (CYP1B1), Catechol-O-methyl transferase (COMT) and Nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1 (NQO1). In addition, there were increased levels of some catechol estrogens e.g. 4-hydroxy-estrone (4-OHE1) and 2-hydroxyestradiol (2-OHE2) with decreased levels of methylated catechols e.g. 2-methoxy estradiol (2-MeOE2). DNA adducts especially 4-OHE1-[2]-1-N3 Adenine was significantly increased. TNF-α directs the estrogen metabolism into more hormonally active and carcinogenic products in MCF-7. This may implicate a new possible explanation for inflammation associated breast cancer.
ABSTRACT
BACKGROUND AND AIM: High risk human papillomavirus (HR-HPV) types have been closely associated with cervical carcinoma. However, other genetic events are likely to be required, in addition to HPV infection, for the development of cervical cancer. We investigated 20 human cervical carcinomas and 15 normal cervical tissues for the correlation between aberrant expression of the FHIT, p53 and MMR genes and their prognostic impact. METHODS AND RESULTS: The expression of p53, FHIT and MMR genes (hMSH2, hMLH1,GTBP/hMSH6,hPMS2, hPMS1) was assessed in relation to HPV infection by immunohistochemistry and PCR. HPV-16 and 18 DNA were detected in 95% and 25%, HPV m-RNA in 90% and 10% of cases; respectively. Homozygous deletion (HZD) and reduced FHIT protein was detected in 40% and 65% of cases, respectively; 25% of which showed abnormal gene transcripts. Reduced MMR gene expression was found in 19 cases. hMSH2 and hMLH1 showed the highest frequency (80% and 70%, respectively). p53 overexpression was present in 50% of cases with a single mutation in exon 7. There was a significant relation between FHIT aberrations, HPV-16 RNA, reduced hMLH-1 and hMSH- 2 expression; between reduced expression of hMSH-2 and p53 overexpression, GTPB-6, as well as between GTPB-6 and hMLH-1. Aberrant expression of p53, FHIT, hMLH1and GTPB-6 was significantly associated with recurrence. CONCLUSIONS: Aberrations involving MMR genes, FHIT and p53 are frequent in HPV-associated cervical carcinoma with a significant correlation between them. However, only the FHIT, p53, hMLH1 and GTPB6 aberrations could be used as predictors of tumor recurrences.
