2-hydroxyestradiol and Ovarian-Neoplasms

Ovarian cancer (OC) is the second most common type of gynecological malignancy. Platinum (Pt)-based chemotherapy is the standard of care for OC, but toxicity and acquired chemoresistance has proven challenging. Recently, we reported that sensitivity to platinum was significantly reduced in a co-culture of OC cells with MSC. To discover compounds capable of restoring platinum sensitivity, we screened a number of candidates and monitored ability to induce PARP cleavage. Moreover, we monitored platinum uptake and expression of ABC transporters in OC cells. Our results showed that 2-hydroxyestradiol (2HE2), a metabolite of estradiol, and dasatinib, an Abl/Src kinase inhibitor, were significantly effective in overcoming MSC-mediated platinum drug resistance. Dasatinib activity was dependent on ERK1/2 activation, whereas 2HE2 was independent of the activation of ERK1/2. MSC-mediated platinum drug resistance was accompanied by reduced intracellular platinum concentrations in OC cells. Moreover, MSC co-cultured with OC cells resulted in downregulation of the expression of cellular transporters required for platinum uptake and efflux. Exposure to 2HE2 and other modulators resulted in an increase in intracellular platinum concentrations. Thus, 2HE2 and dasatinib might act as sensitizers to restore platinum drug sensitivity to OC cells and thus to limit TME-mediated chemoresistance in OC.

Topics: Antineoplastic Agents; Cell Line, Tumor; Drug Resistance, Neoplasm; Estradiol; Female; Humans; MAP Kinase Signaling System; Mesenchymal Stem Cells; Organoplatinum Compounds; Ovarian Neoplasms; Platinum

Estradiol 17β (E2β) and ascorbic acid (AA) have been implicated in cancer progression. However, little is known about the actions of biologically active metabolites of E2β, 2-hydroxyestradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 2-methoxyestradiol (2ME2), and 4-methoxyestradiol (4ME2) synthesized sequentially by cytochrome P450, family 1, subfamily A (CYP1A1) and B (CYP1B1), polypeptide 1, and catechol-O-methyltransferase (COMT) on ovarian cancer. Herein, we examined the expression of CYP1A1, CYP1B1, COMT, and estrogen receptor α (ERα) and β (ERβ) in human ovarian surface epithelial (IOSE-385) and cancer cell lines (OVCAR-3, SKOV-3, and OVCA-432). We also investigated the roles of E2β, 2OHE2, 4OHE2, 2ME2, and 4ME2 in cell proliferation, and their interactive effects with AA on ovarian cells. We found the expression of CYP1A1, CYP1B1, COMT, ERα, and ERβ in most cell lines tested. Treating cells with physiological concentrations of E2β and its metabolites promoted (13%-42% of the control) IOSE-385 and OVCAR-3 proliferation. The ER blockade inhibited IOSE-385 (∼76%) and OVCAR-3 (∼87%) proliferative response to E2β but not to its metabolites. The ERα blockade inhibited (∼85%) E2β-stimulated OVCAR-3 proliferation, whereas ERβ blockade attenuated (∼83%) E2β-stimulated IOSE-385 proliferation. The AA at ≥250 μmol/L completely inhibited serum-stimulated cell proliferation in all cell lines tested; however, such inhibition in IOSE-385, OVCAR-3, and OVCA-432 was partially (∼10%-20%) countered by E2β and its metabolites. Thus, our findings indicate that E2β and its metabolites promote cell proliferation and antagonize the AA-suppressed cell proliferation in a subset of ovarian cancer cells, suggesting that blocking the actions of E2β and its metabolites may enhance AA's antiovarian cancer activity.

Topics: 2-Methoxyestradiol; Aryl Hydrocarbon Hydroxylases; Ascorbic Acid; Catechol O-Methyltransferase; Cell Line, Tumor; Cell Proliferation; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Dose-Response Relationship, Drug; Drug Interactions; Estradiol; Estrogen Antagonists; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens, Catechol; Female; Humans; Ovarian Neoplasms; Time Factors

Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric basic helix-loop-helix transcription factor composed of HIF-1alpha and HIF-1beta subunits. HIF-1 expression is induced by hypoxia, growth factors, and activation of oncogenes. HIF-1 activates downstream target genes such as vascular endothelial growth factor A (VEGF-A), which plays an important role in tumor progression and angiogenesis. Estrogen exposure is considered to be the major risk factor for ovarian cancer. Estradiol (E2) is usually metabolized by CYP1A1/1A2 and CYP3A4 to the 2-hydroxy estradiol (2-OHE2) and 4-hydroxy estradiol (4-OHE2) in human liver. Many reports have suggested that the formation of 4-OHE2 is important for mammary carcinogenesis. However, the formation of 2-OHE2 may play an important role in exhibiting anticarcinogenic effects. In the present study, we have demonstrated that one of the catechol estrogen metabolites of E2, 4-OHE2, induces HIF-1alpha and VEGF-A expression at protein level in two human ovarian cancer cell lines, OVCAR-3 and A2780-CP70 cells, in dose- and time-dependent manners, whereas the other catechol estrogen metabolite of E2, 2-OHE2, does not alter HIF-1alpha and VEGF-A expression. To explore the mechanism of 4-OHE2-induced HIF-1alpha and VEGF-A expression, we studied whether phosphatidylinositol 3-kinase (PI3K) or mitogen-activated protein kinase (MAPK) signaling pathways are involved in 4-OHE2-induced HIF-1alpha and VEGF-A expression. Our findings indicate that PI3K inhibitors, LY294002 and wortmannin, inhibited HIF-1alpha and VEGF-A expression, whereas MAPK inhibitor, PD98059, did not alter HIF-1alpha and VEGF-A expression induced by 4-OHE2. 4-OHE2, but not 2-OHE2, also induced Akt phosphorylation at Ser473 in dose- and time-dependent manners, and LY294002 and wortmannin inhibited Akt phosphorylation at Ser473 induced by 4-OHE2. Our results also indicated that the mTOR/FRAP inhibitor, rapamycin, inhibited 4-OHE2-induced HIF-1alpha and VEGF-A expression. These results suggest that the PI3K/Akt/FRAP signaling pathway is required for HIF-1alpha and VEGF-A expression induced by 4-OHE2, whereas the MAPK pathway is not required. The finding that induction of HIF-1alpha and VEGF-A expression occurs via the activation of the PI3K/Akt/FRAP signaling pathway could be an important mechanism of 4-OHE2-induced carcinogenesis.

Topics: Cell Line, Tumor; Enzyme Inhibitors; Estradiol; Estrogens, Catechol; Female; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mitogen-Activated Protein Kinases; Ovarian Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Transcription Factors; Vascular Endothelial Growth Factor A