3-methylquercetin and Breast-Neoplasms

Acquired resistance to doxorubicin (DOX) inevitably limits its clinical use against breast cancer (BC). Isorhamnetin (IS), a native flavonoid which extensively available in vegetables, fruits, and phytomedicine, has been deemed to the probable cancer chemopreventive agent in preceding explorations since it exhibits satisfied antitumor activity. So far, the strategy for alleviating DOX resistance by using IS as a sensitizer against resistant BC has not yet been covered.. To investigate the effect of IS on potentiating the chemoreceptivity of drug-resistant BC cells to DOX in vitro and in vivo and elucidate the possible molecular mechanisms.. MTS assays, colony formation assays, three-dimensional (3D) tumor spheroid model, and migration assay were deployed to verify the inhibiting action of IS in the presence or absence of DOX on resistant BC cells in vitro. Apoptosis, cell cycle regulation, and endocellular reactive oxygen species (ROS) were determined by flow cytometry. Protein levels were monitored by western blotting. Nuclear staining and EdU proliferation were photographed with a confocal laser scanning microscope. The effects of the IS and DOX combination on the tumorigenesis in the xenograft experiments were evaluated for further confirming the in vitro cytotoxicity.. IS significantly inhibited cell proliferation and migration and enhanced the antitumor competence of DOX against resistant BC cells both in vitro and in vivo. Adjuvant IS (50 μM) effectively enhanced the proapoptotic impacts of DOX in resistant BC cells (35.38 ± 3.18%, vs. 5.83 ± 0.68% in the DOX group) by suppressing the expression of bcl 2 in addition to enhancing cleaved caspase 3, ultimately leading to DNA condensation and fragmentation. IS (20, 30, and 50 μM) treatments induced significant increases in the G2/M populations (41.60 ± 1.28%, 44.60 ± 1.14%, and 50.64 ± 0.67%, vs. 35.84 ± 1.56% in the untreated control in MCF7/ADR cells, p < 0.01) via regulating CDK1/Cyclin B1 complex expression, subsequently triggering the inhibition of BC proliferation. In addition, IS (10, 20, 30, and 50 μM) stimulated the production of interstitial ROS in MCF7/ADR cells, by 3.99-, 4.20-, 6.29-, and 6.78-fold, respectively, versus the untreated group (p < 0.001), which were involved in DNA damage and AMPK-caused intercept of the mTOR/p70S6K signaling.. Our study suggested the anti-breast cancer actions of IS as a DOX sensitizer and expounded the underlying molecular mechanisms, showing that IS could be deemed to a capable alternative for resistant BC cure.

Topics: AMP-Activated Protein Kinases; Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; DNA Damage; Doxorubicin; Drug Resistance, Neoplasm; Female; Humans; Reactive Oxygen Species; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases

Natural products are a valuable source of new molecules and are important for drug discovery. Many chemotherapeutics currently in clinical use were originated from natural sources and are effective cytotoxic agents. In this study, we investigated the cytotoxic and pro-apoptotic effects of achyrobichalcone (ACB) and 3-O-methylquercetin (3OMQ), two novel compounds isolated from the Achyrocline satureioides plant. Because extracts from this plant have been shown to have anticancer activity in vitro, we evaluated ACB and 3OMQ using a human breast cancer cell line, MDA-MB-231, and a nontumorigenic human breast epithelial cell line, MCF-12A. We found that ACB demonstrates cytotoxic effects on MDA-MB-231 cells, but not MCF-12A cells. 3OMQ also demonstrated cytotoxic effects on MDA-MB-231 cells, but with lower selectivity compared to treated MCF-12A cells. Cell death by both compounds was associated with caspase-9 and caspase-3/7 activation. Using high-resolution respirometry, we found that ACB and 3OMQ were able to cause acute mitochondrial dysfunction in MDA-MB-231-treated cells. These results suggest that apoptosis in MDA-MB-231 cells is induced through the activation of the mitochondrial-dependent pathway. Collectively, these findings suggest that ACB is a strong candidate for further anticancer in vivo tests.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Biflavonoids; Breast Neoplasms; Caspase 3; Cell Line, Tumor; Dose-Response Relationship, Drug; Female; Humans; Mitochondria; Quercetin

Matrix metalloproteinases (MMPs) play an active role in facilitating the invasion of cancer cells with excessive extracellular matrix (ECM) degradation. In the present study, we investigated the antiinvasive effects of isorhamnetin, a naturally occurring flavonoid, on MDA-MB-231 human breast carcinoma cells. The results indicated that isorhamnetin significantly inhibited the adhesion, migration, and invasion of the cells in vitro. Moreover, isorhamnetin suppressed the activity and expression of MMP-2 and MMP-9, which were determined by gelatin zymography, real-time PCR, and Western blot analysis, respectively. Besides, isorhamnetin had little effect on the secretion of urokinase plasminogen activator. Further elucidation of the mechanism revealed that isorhamnetin exerted an inhibitory effect on the phosphorylation of p38 and STAT3, although it had no effect on ERK1/2 and JNK. Taken together, these data demonstrated that isorhamnetin could significantly inhibit the invasion of MDA-MB-231 cells by downregulating the expression and activity of MMP-2 and MMP-9, which was potentially associated with the suppression of p38 MAPK and STAT3. Therefore, the findings provide new evidence for the anti-cancer activity of isorhamnetin.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Survival; Down-Regulation; Female; Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; p38 Mitogen-Activated Protein Kinases; Quercetin; STAT3 Transcription Factor

Breast cancer is the most common cause of female cancer-associated mortality. Although treatment options, including chemotherapy, radiotherapy and surgery have led to a decline in the mortality rates associated with breast cancer, drug resistance remains one of the predominant causes for poor prognosis and high recurrence rates. The present study investigated the potential effects of the natural product, isorhamnetin on breast cancer, and examined the effects of isorhamnetin on the Akt/mammalian target of rapamycin (mTOR) and the mitogen-activated protein kinase (MAPK)/MAPK kinase (MEK) signaling cascades, which are two important signaling pathways for endocrine therapy resistance in breast cancer. The results of the present study indicate that isorhamnetin inhibits cell proliferation and induces cell apoptosis. In addition, isorhamnetin was observed to inhibit the Akt/mTOR and the MEK/extracellular signal-regulated kinase phosphorylation cascades. The inhibition of these two signaling pathways was attenuated by the two Akt and MEK1 inhibitors, but not by the nuclear factor-κB inhibitor. Furthermore, epidermal growth factor inhibited the effects of isorhamnetin via activation of the Akt and MEK signaling pathways. These results indicate that isorhamnetin exhibits antitumor effects in breast cancer, which are mediated by the Akt and MEK signaling pathways.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Screening Assays, Antitumor; Epidermal Growth Factor; Female; Humans; MAP Kinase Signaling System; NF-kappa B; Proto-Oncogene Proteins c-akt; Quercetin

Quercetin, kaempferol and isorhamnetin are the most important constituents in ginkgo flavonoids. A simple, rapid and sensitive high-performance liquid chromatography method was developed to simultaneously determine quercetin, kaempferol and isorhamnetin absorped by human breast cancer cells. Cells were treated with ginkgo flavonols and then lysed with Triton-X 100. The flavonols in the samples were measured by RP-HPLC with a C18 column after a simple extraction with a mixture of ether and acetone. The mobile phase contained phosphate buffer (pH 2.0; 10 mM) tetrahydrofuran, methanol and isopropanol (65:15:10:20, v/v/v/v). The ultraviolet detector was operated at 380 nm. The calibration curve was linear from 0.1 to 1.0 microM (r > 0.999) for each flavonol. The mean extraction efficiency was about 70%. The recovery of the assay was between 98.9 and 100.6%. The limit of detection was 0.01 microM for quercetin and kaempferol and 0.05 microM for isorhamnetin. The limit of quantitation was 0.1 microM (R.S.D.<10%) for each flavonol. The intra- and inter-day coefficients of variation were less than 10% (R.S.D.). The validated method was applied to quantify quercetin, kaempferol and isorhamnetin in human breast cancer Bcap37 and Bcap37/MDR1 cells.

Topics: Breast Neoplasms; Calibration; Cell Line, Tumor; Chromatography, High Pressure Liquid; Flavonols; Humans; Kaempferols; Prohibitins; Quercetin; Reference Standards; Reproducibility of Results; Sensitivity and Specificity; Spectrophotometry, Ultraviolet