Quercetin inhibits prostate cancer by attenuating cell survival and inhibiting anti-apoptotic pathways.

BACKGROUND: Despite recent advances in diagnosis and treatment, prostate cancer (PCa) remains the leading cause of cancer-related deaths in men. Current treatments offered in the clinics are often toxic and have severe side effects. Hence, to treat and manage PCa, new agents with fewer side effects or having potential to reduce side effects of conventional therapy are needed. In this study, we show anti-cancer effects of quercetin, an abundant bioflavonoid commonly used to treat prostatitis, and defined quercetin-induced cellular and molecular changes leading to PCa cell death. METHODS: Cell viability was assessed using MTT. Cell death mode, mitochondrial outer membrane potential, and oxidative stress levels were determined by flow cytometry using Annexin V-7 AAD dual staining kit, JC-1 dye, and ROS detection kit, respectively. Antibody microarray and western blot were used to delineate the molecular changes induced by quercetin. RESULTS: PCa cells treated with various concentrations of quercetin showed time- and dose-dependent decrease in cell viability compared to controls, without affecting normal prostate epithelial cells. Quercetin led to apoptotic and necrotic cell death in PCa cells by affecting the mitochondrial integrity and disturbing the ROS homeostasis depending upon the genetic makeup and oxidative status of the cells. LNCaP and PC-3 cells that have an oxidative cellular environment showed ROS quenching after quercetin treatment while DU-145 showed rise in ROS levels despite having a highly reductive environment. Opposing effects of quercetin were also observed on the pro-survival pathways of PCa cells. PCa cells with mutated p53 (DU-145) and increased ROS showed significant reduction in the activation of pro-survival Akt pathway while Raf/MEK were activated in response to quercetin. PC-3 cells lacking p53 and PTEN with reduced ROS levels showed significant activation of Akt and NF-κB pathway. Although some of these changes are commonly associated with oncogenic response, the cumulative effect of these alterations is PCa cell death. CONCLUSIONS: Our results demonstrated quercetin exerts its anti-cancer effects by modulating ROS, Akt, and NF-κB pathways. Quercetin could be used as a chemopreventive option as well as in combination with chemotherapeutic drugs to improve clinical outcomes of PCa patients.

Proteomic signatures of acquired letrozole resistance in breast cancer: suppressed estrogen signaling and increased cell motility and invasiveness.

Aromatase inhibitors, such as letrozole, have become the first-line treatment for postmenopausal women with estrogen-dependent breast cancer. However, acquired resistance remains a major clinical obstacle. Previous studies demonstrated constitutive activation of the MAPK signaling, overexpression of HER2, and down-regulation of aromatase and ERα in letrozole-resistant breast cancer cells. Given the complex signaling network involved in letrozole-refractory breast cancer and the lack of effective treatment for hormone resistance, further investigation of aromatase inhibitor resistance by a novel systems biology approach may reveal previously unconsidered molecular changes that could be utilized as therapeutic targets. This study was undertaken to characterize for the first time global proteomic alterations occurring in a letrozole-resistant cell line. A quantitative proteomic analysis of the whole cell lysates of LTLT-Ca (resistant) versus AC-1 cells (sensitive) was performed to identify significant protein expression changes. A total of 1743 proteins were identified and quantified, of which 411 were significantly up-regulated and 452 significantly down-regulated (p < 0.05, fold change > 1.20). Bioinformatics analysis revealed that acquired letrozole resistance is associated with a hormone-independent, more aggressive phenotype. LTLT-Ca cells exhibited 84% and 138% increase in migration and invasion compared with the control cells. The ROCK inhibitor partially abrogated the enhanced migration and invasion of the letrozole-resistant cells. Flow cytometric analyses also demonstrated an increase in vimentin and twist expression in letrozole-resistance cells, suggesting an onset of epithelial to mesenchymal transition (EMT). Moreover, targeted gene expression arrays confirmed a 28-fold and sixfold up-regulation of EGFR and HER2, respectively, whereas ERα and pS2 were dramatically reduced by 28-fold and 1100-fold, respectively. Taken together, our study revealed global proteomic signatures of a letrozole-resistant cell line associated with hormone independence, enhanced cell motility, EMT and the potential values of several altered proteins as novel prognostic markers or therapeutic targets for letrozole resistant breast cancer.

Palliative Appropriateness Criteria: A Pragmatic Method to Evaluate the Suitability of Palliative Radiotherapy Fractionation.

Purpose: To describe a novel metric to aid clinical decision making between shorter versus longer palliative radiotherapy (PRT) regimens using objective patient factors. Materials and Methods: Patients receiving PRT at a single institution between 2014 and 2018 were reviewed. The time between PRT start and finish was calculated and divided by overall survival (in days from start of PRT) to generate the percent of remaining life (PRL). This value was compared across various clinical factors using the Kruskal-Wallis test. Factors identified with a significance level p < 0.01 were included in a novel Palliative Appropriateness Criteria Score (PACS) and were included in an online risk assessment tool to assist clinicians in patient-specific fractionation decisions. Results: Totally 1027 courses of PRT were analyzed. Median age was 64 years; Eastern Cooperative Oncology Group (ECOG) performance status was 3-4 in 22%. Primary malignancies included were lung (38%), breast (13.8%), prostate (9.3%), and other (39%). The indication for PRT was pain (61%), neurological (21%), or other (18%). Palliative regimens included 199 (19.4%) receiving single fraction, 176 (17.1%) receiving 2-5 fractions, and 652 (63.5%) receiving 10 fractions. Median follow-up was 83 days overall and 437 days for patients alive at last follow-up. Factors significantly associated with increased PRL (and included in the PACS) were male gender, ECOG 3-4, lung or "other" primary diagnosis (vs. breast or prostate), PRT indication (neurological dysfunction vs. pain/other), inpatient status, and extraosseous sites treatment. Death within 30 days was significantly associated with high-risk PACS categorization, regardless of fractionation scheme (p < 0.001). Conclusions: The PACS is a novel metric for evaluating the utility of PRT regimens to improve clinical decision making. Single fraction is associated with low PRL. When considering multifraction PRT regimens, the PACS identifies patients who may benefit from shorter courses of PRT and alternatively, low-risk patients for whom a more protracted course is reasonable. Prospective external validation is warranted.

Pilot study to assess sexual function, quality of life (QOL) and change in vaginal dimensions following vaginal brachytherapy (VBT).

METHODS: 63 patients with early stage endometrial carcinoma treated with VBT 30 Gy in three fractions to the vaginal surface were invited to participate. 18 patients enrolled. Vaginal length and diameter were measured using original VBT cylinders to assess change. Patients completed sexual function, QOL, and toxicity questionnaires. The assessment of patients' sexual function relative to national mean was calculated and reported by the Health Measures Scoring Service, a third party. RESULTS: Median length of time from VBT start until research visit was 3.6 years. Mean original vaginal length of the 18 women was 13.7 cm (Range: 11-18 cm); mean original diameter was 3.0 cm (Range: 2.5-3.5 cm). There was a significant decrease in vaginal length of 1.2 cm (p = 0.0005). There was a mean vaginal diameter decrease of 0.03 cm that was not significant. Toxicities were grade 1-2 and infrequent. There were no grade two acute toxicities, and 1 patient (5.6%) who had a chronic toxicity, diarrhea. 7 patients had evaluable sexual function responses. Reported sexual function was above the national mean in global satisfaction, interest, and lubrication (52.9, 50.2, and 56.2 percentile). Patients performed beneath national mean in the categories of orgasm and discomfort (3.1, 46.7 percentile) which was not correlated with the decrease in vaginal length. DISCUSSION/CONCLUSION: VBT resulted in significant vaginal shortening. Patients underperformed in the categories of orgasm and vaginal discomfort relative to national mean. This report adds to the scarce literature of objective data on sexual satisfaction and vaginal sequelae of VBT for endometrial carcinoma.

Cinnamtannin B-1 inhibits cell survival molecules and induces apoptosis in colon cancer.

Colon cancer patients receiving chemotherapy continue to be burdened with therapeutic failure and adverse side effects, yielding a need to develop more effective treatments. The present study investigates Cinnamtannin B-1 (CTB-1) as a potential low-toxicity therapeutic alternative for colon cancer. CTB-1-treated DLD-1, COLO 201 and HCT-116 (WT p53 and p53 null) colon cancer cells and CCD 841 CoN normal colon epithelial cells were assessed for changes in survival using MTT assay. The effects of CTB-1 on cell cycle progression and the apoptosis of colon cancer cells were measured using flow cytometry and/or immunofluorescence. The expression profiles of cell survival molecules, particularly apoptotic proteins, in the colon cancer cells were evaluated following CTB-1 treatment via antibody array, then validated by western blot analysis. Additionally, the potential synergy between CTB-1 and 5-fluorouracil (5-FU), a conventional chemotherapeutic agent used in the treatment of colon cancer, against colon cancer cells was assessed using MTT assay and Calcusyn software. The results revealed that CTB-1 significantly decreased the survival of the DLD-1, COLO 201 and HCT-116 cells in a time and/or dose-dependent manner, with minimal cytotoxicity to normal colon cells. CTB-1 treatment was shown to induce cell cycle arrest and apoptosis of DLD-1 and COLO 201 cells. Of note, CTB-1 modulated the expression of several cell survival molecules, which tend to be deregulated in colon cancer, including p53, a key transcription factor involved in apoptosis. The downstream regulation of Bcl-2 and Bak expression, as well as cytochrome c release into the cytosol, was also observed following CTB-1 treatment. Furthermore, CTB-1 was shown to significantly enhance the potency of 5-FU via a synergistic drug interaction. This study reveals for the first time, to the best of our knowledge, the ability of CTB-1 to decrease the survival of colon cancer cells through pro-apoptotic mechanisms and display synergy with conventional chemotherapy, demonstrating the potential therapeutic benefit of CTB-1 in colon cancer.

Protein Kinase CK2 Expression Predicts Relapse Survival in ERα Dependent Breast Cancer, and Modulates ERα Expression in Vitro.

The heterotetrameric protein kinase CK2 has been associated with oncogenic transformation, and our previous studies have shown that it may affect estrogenic signaling. Here, we investigate the role of the protein kinase CK2 in regulating ERα (estrogen receptor α) signaling in breast cancer. We determined the correlation of CK2α expression with relapse free breast cancer patient survival utilizing Kaplan Meier Plotter (kmplot.com/analysis/) to mine breast cancer microarrays repositories. Patients were stratified according to ERα status, histological grade, and hormonal therapy. Luciferase reporter assays and flow cytometry were implemented to determine the impact of CK2 inhibition on ERE-mediated gene expression and expression of ERα protein. CK2α expression is associated with shorter relapse free survival among ERα (+) patients with grade 1 or 2 tumors, as well as among those patients receiving hormonal therapy. Biochemical inhibition of CK2 activity results in increased ER-transactivation as well as increased expression among ERα (+) and ERα (-) breast cancer cell lines. These findings suggest that CK2 may contribute to estrogen-independent cell proliferation and breast tumor progression, and may potentially serve as a biomarker and pharmacological target in breast cancer.

Glyceollin I Reverses Epithelial to Mesenchymal Transition in Letrozole Resistant Breast Cancer through ZEB1.

Although aromatase inhibitors are standard endocrine therapy for postmenopausal women with early-stage metastatic estrogen-dependent breast cancer, they are limited by the development of drug resistance. A better understanding of this process is critical towards designing novel strategies for disease management. Previously, we demonstrated a global proteomic signature of letrozole-resistance associated with hormone-independence, enhanced cell motility and implications of epithelial mesenchymal transition (EMT). Letrozole-resistant breast cancer cells (LTLT-Ca) were treated with a novel phytoalexin, glyceollin I, and exhibited morphological characteristics synonymous with an epithelial phenotype and decreased proliferation. Letrozole-resistance increased Zinc Finger E-Box Binding Homeobox 1 (ZEB1) expression (4.51-fold), while glyceollin I treatment caused a -3.39-fold reduction. Immunofluorescence analyses resulted of glyceollin I-induced increase and decrease in E-cadherin and ZEB1, respectively. In vivo studies performed in ovariectomized, female nude mice indicated that glyceollin treated tumors stained weakly for ZEB1 and N-cadherin and strongly for E-cadherin. Compared to letrozole-sensitive cells, LTLT-Ca cells displayed enhanced motility, however in the presence of glyceollin I, exhibited a 68% and 83% decrease in invasion and migration, respectively. These effects of glyceollin I were mediated in part by inhibition of ZEB1, thus indicating therapeutic potential of glyceollin I in targeting EMT in letrozole resistant breast cancer.

Phytoalexins, miRNAs and breast cancer: a review of phytochemical-mediated miRNA regulation in breast cancer.

There is growing interest in the diverse signaling pathways that regulate and affect breast tumorigenesis, including the role of phytochemicals and the emerging role of microRNAs (miRNAs). Recent studies demonstrate that miRNAs regulate fundamental cellular and developmental processes at the transcriptional and translational level under normal and disease conditions. While there is growing evidence to support the role of phytoalexin-mediated miRNA regulation of cancer, few reports address this role in breast cancer. Recent reports by our group and others demonstrate that natural products, including stilbenes, curcumin, and glyceollins, could alter the expression of specific miRNAs, which may lead to increased sensitivity of cancer cells to conventional anti-cancer agents and, therefore, hormone-dependent and hormone-independent tumor growth inhibition. This review will discuss how dietary intake of natural products, by regulating specific miRNAs, contribute to the prevention and treatment of breast cancer.

In vitro and in vivo evaluation of novel anticancer agents in triple negative breast cancer models.

Triple negative breast cancer (TNBC) is subtype of breast disease devoid of the estrogen, progesterone, and Her2/neu receptors which are targets for pharmacological intervention. There is a need for novel anti-breast cancer agents that target TNBC. Therefore, novel isochalcone DJ52 was evaluated using the alamar blue dye exclusion assay, the luciferase colony assay, and xenograft models to determine its efficacy and potency. DJ52 significantly decreased proliferation of cells measured by using the alamar blue dye method and produced IC50 values of DJ52, DJ56, and DJ82 at 10-6M, 10-5M, and 10-5M, respectively. In vivo studies were conducted by injecting MDA-MB-231 cells into SCID mice to determine tumor regression was measured over 20 days. DJ52 at 50 mg/kg caused significant decrease in tumor volume (p value <.05) by nearly 50% compared with the control with vehicle alone. These data suggest that DJ52 has merit for further evaluation as a novel anticancer agent.

Toxicity and biouptake of lead and arsenic by Daphnia pulex.

Acute and chronic toxicity studies were conducted on Daphnia pulex using synthetic lead and arsenic water samples. For acute studies, solutions with 0.25, 0.5, 1.0, 2.0, 5.0 mg/L lead and arsenic along with a control were used. The chronic studies were conducted for 21 days using 0.25, 0.5, 1.0 mg/L lead and arsenic solutions along with a control. Results indicated that the LC50 (48 hour) was 4.0 and 3.4 mg/L for lead and arsenic, respectively. Results from chronic studies suggest that the exposure to lead solutions significantly (P < 0.05) impaired the reproduction rates of Daphnia at the 1 mg/L concentration. However, the reproduction rates were enhanced at low concentrations of arsenic (up to 0.5 mg/L). A second chronic study was conducted to confirm this finding. Results from the second study indicated that lead exhibited significantly higher (P < 0.05) toxicity at 0.5 mg/L concentration, while reproduction rates in all concentrations of arsenic solutions were not significantly different from the controls. Metal analysis on exposed Daphnia, following nitric acid digestion procedures, indicated that Daphnia bio-accumulated 75.3-97.2% of the lead added to the experimental containers. This high lead biouptake coupled with the fast growth, high reproduction rates, and short life cycle all suggest that a Daphnia-based remediation (growth and partial harvest) may a viable treatment alternative that is worth considering. However, further field studies have to be conducted to verify this alternative. Biouptake or sequestration by Daphnia of arsenic at all tested concentrations was negligible, thereby, suggesting selective uptake or sequestration by daphnia under the tested pH and temperature conditions.