PURPOSE: The reason why chemotherapy induces resistance to subsequent hormonal therapy remains to be clarified in postmenopausal breast cancers. We hypothesized that chemotherapy might down-regulate the intratumoral biosynthesis of estrogens. Thus, we have studied the influence of chemotherapy (docetaxel) on intratumoral aromatase mRNA expression because aromatase is a key enzyme for intratumoral biosynthesis of estrogens. EXPERIMENTAL DESIGN: The mRNA levels of aromatase and its inducers [tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and cyclooxygenase 2 (COX-2)] were determined by a real-time polymerase chain reaction assay in breast cancer tissues obtained before and after neoadjuvant chemotherapy with docetaxel (four cycles of 60 mg/m2 every 3 weeks) in 16 postmenopausal patients with estrogen receptor (ER)- and/or progesterone receptor (PR)-positive breast cancers. ER and PR levels in tumor tissues were also determined by enzyme immunoassay before and after chemotherapy. RESULTS: The intratumoral aromatase mRNA levels decreased significantly (P < 0.05) after chemotherapy from 0.84 +/- 0.28 (mean +/- SE) to 0.47 +/- 0.28. The intratumoral TNF-alpha mRNA levels also decreased significantly (P < 0.05) after chemotherapy from 2.40 +/- 0.52 to 0.95 +/- 0.25. On the contrary, the intratumoral IL-6 and COX-2 mRNA levels showed a marginally significant increase (P = 0.07) and a significant increase (P < 0.05), respectively, after chemotherapy. PR levels showed a marginally significant decrease (P = 0.08) after chemotherapy, whereas ER levels were almost constant before and after chemotherapy. CONCLUSIONS: Antitumor activity of docetaxel is mediated, at least in part, through a down-regulation of aromatase expression in tumor tissues, resulting in the suppression of intratumoral estradiol synthesis. Aromatase expression seems to be regulated mostly by TNF-alpha, but not IL-6 and COX-2.
PURPOSE: The reason why chemotherapy induces resistance to subsequent hormonal therapy remains to be clarified in postmenopausal breast cancers. We hypothesized that chemotherapy might down-regulate the intratumoral biosynthesis of estrogens. Thus, we have studied the influence of chemotherapy (docetaxel) on intratumoral aromatase mRNA expression because aromatase is a key enzyme for intratumoral biosynthesis of estrogens. EXPERIMENTAL DESIGN: The mRNA levels of aromatase and its inducers [tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and cyclooxygenase 2 (COX-2)] were determined by a real-time polymerase chain reaction assay in breast cancer tissues obtained before and after neoadjuvant chemotherapy with docetaxel (four cycles of 60 mg/m2 every 3 weeks) in 16 postmenopausal patients with estrogen receptor (ER)- and/or progesterone receptor (PR)-positive breast cancers. ER and PR levels in tumor tissues were also determined by enzyme immunoassay before and after chemotherapy. RESULTS: The intratumoral aromatase mRNA levels decreased significantly (P < 0.05) after chemotherapy from 0.84 +/- 0.28 (mean +/- SE) to 0.47 +/- 0.28. The intratumoral TNF-alpha mRNA levels also decreased significantly (P < 0.05) after chemotherapy from 2.40 +/- 0.52 to 0.95 +/- 0.25. On the contrary, the intratumoral IL-6 and COX-2 mRNA levels showed a marginally significant increase (P = 0.07) and a significant increase (P < 0.05), respectively, after chemotherapy. PR levels showed a marginally significant decrease (P = 0.08) after chemotherapy, whereas ER levels were almost constant before and after chemotherapy. CONCLUSIONS: Antitumor activity of docetaxel is mediated, at least in part, through a down-regulation of aromatase expression in tumor tissues, resulting in the suppression of intratumoral estradiol synthesis. Aromatase expression seems to be regulated mostly by TNF-alpha, but not IL-6 and COX-2.
Authors: S Giovinazzi; C R Lindsay; V M Morozov; E Escobar-Cabrera; M K Summers; H S Han; L P McIntosh; A M Ishov Journal: Oncogene Date: 2011-06-06 Impact factor: 9.867
Authors: Alicia González-González; Enrique García Nieto; Alicia González; Cristina Sánchez-Fernández; Carolina Alonso-González; Javier Menéndez-Menéndez; José Gómez-Arozamena; Samuel Cos; Carlos Martínez-Campa Journal: Int J Mol Sci Date: 2019-08-13 Impact factor: 5.923