Limonin breast tissue compared to healthy breast tissue . These findings were similar for ovarian cancer cases, but without statistical significance . Calcitriol, as shown in numerous previous studies, plays an important role in carcinoma cell growth, as well as in inflammatory pathways. Vitamin D and its metabolites inhibit cancer cell growth in cell cultures and supress proliferation in xenografts of human tumours . In our present data, an inverse correlation between the VDR expression, COX-2 and 15-PGDH expressions was detectable, as well as between 2 D 3 and PGE 2 serum levels. Higher levels of COX-2 expression were observed by western blotting in both types of malignant tissues compared to benign samples.
Our data are consistent with several other studies and might give evidence that COX-2 is Rutoside overexpressed in cancer patients due to increased proliferation, reduced apoptosis, or enhanced neoangiogenesis . In our present study, COX-2 expression was detected by Western blot. Other studies mainly used immunohistochemistry ; however, these immunohistochemical methods were not quantitative and would strongly depend on the quality of the antibody and the staining protocol, as well as the selection of the analysed region. Therefore, the variations in findings for COX-2 expression among different studies may partly be attributed to different scoring systems and cut-off values used for COX-2 immunoreactivity . In a literature review, we found a detection rate of COX-2 protein expression in malignant breast tissue to be 40% on average by purchase Bosutinib immuno his to chemistry and of COX-2 mRNA expression on an average of 90%.
Thus it seems likely that COX-2 may undergo complex posttranscriptional and post-translational modifications to yield the active enzyme . A significant difference between tumor and normal breast tissue samples was found in western blot analysis for 15PGDH levels. A study by Wolf et al. presented low 15PGDH expression in estrogen order Gastrodin receptor -negative breast cancer samples in contrast to high expression in ER-positive tumours . This is contradictory to our results; low levels of 15-PGDH are often associated with ER-negative tumors that exhibit a metastatic potential and correlate with unfavourable prognostic factors . An ER-negative status was found in 5/22 of the analysed breast cancer samples and 3/5 of the ER-negative samples were triple negative . This might be an explanation for significantly higher 15-PGDH expression in our breast cancer samples. A therapeutical approach is to target COX-2 enzyme activity by blocking binding of PGE 2 ligand to the EP receptor.
However, the role of PGE 2 receptors EP 1-4 is still under investigation. EP 1 , EP 2 and wavelength EP 4 all appear to have pro- in MCF-7 and MDA-MB cells; greater invasiveness resulted in lower receptor levels . This might be in line with our results, as we found lower EP 2 and EP 4 expression in malignant tissue. As a possible consequence, COX-2 is highly expressed in a subset of breast carcinomas.