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Stress hormones reduce the efficacy of paclitaxel in triple negative breast cancer through induction of DNA damage.

ABSTRACT: The mechanisms by which stress hormones impact triple-negative breast cancer (TNBC) etiology and treatment are unclear. We have previously shown that stress hormones, cortisol, and catecholamines induce rapid DNA damage and impact DNA repair in NIH 3T3 fibroblasts. This study investigates whether stress hormones increase DNA damage in breast cancer cells and if this impacts drug efficacy.We first screened a panel of 39 breast cancer cell lines for expression of adrenergic and glucocorticoid receptors and examined if stress hormones induce DNA damage and alter cell cycle regulation in vitro. A TNBC xenograft model was used to assess the impact of restraint stress on tumour growth and chemosensitivity to paclitaxel.We found that stress hormones induced DNA damage, phosphorylation of ATR, which was accompanied by an up-regulation of the G1 cell kinase inhibitor p21 and a cell cycle halt of TNBCs in the G1 phase. p21 knockdown abrogated G1 arrest by stress hormones. We also demonstrated that stress significantly decreased efficacy of paclitaxel.We describe a novel mechanism through which stress hormones can induce drug resistance to paclitaxel, which may have profound implications for treating drug resistance in patients with TNBC.

SUBMITTER: Reeder A

PROVIDER: S-EPMC4453678 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

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Stress hormones reduce the efficacy of paclitaxel in triple negative breast cancer through induction of DNA damage.

Reeder A A Attar M M Nazario L L Bathula C C Zhang A A Hochbaum D D Roy E E Cooper K L KL Oesterreich S S Davidson N E NE Neumann C A CA Flint M S MS

British journal of cancer 20150416 9

<h4>Background</h4>The mechanisms by which stress hormones impact triple-negative breast cancer (TNBC) etiology and treatment are unclear. We have previously shown that stress hormones, cortisol, and catecholamines induce rapid DNA damage and impact DNA repair in NIH 3T3 fibroblasts. This study investigates whether stress hormones increase DNA damage in breast cancer cells and if this impacts drug efficacy.<h4>Methods</h4>We first screened a panel of 39 breast cancer cell lines for expression of ...[more]

PMID: 25880007

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Project description:BackgroundPaclitaxel (PTX), a first-line therapy for triple negative breast cancers (TNBC) induces anti-tumor activity by microtubule stabilization and inhibition of cell division. Its dose-limiting toxicity and short half-life, however, pose clinical challenges underscoring the need for strategies that increase its efficiency. RAD6, a E2 ubiquitin conjugating enzyme, is associated with centrosomes at all phases of cell cycle. Constitutive overexpression of the RAD6B homolog in normal breast cells induces centrosome amplification and multipolar spindle formation, indicating its importance in centrosome regulation.MethodsTNBC centrosome numbers were scored by pericentrin immunostaining. PTX sensitivities and interactions with SMI#9, a RAD6-selective small molecule inhibitor, on TNBC cell survival were analyzed by MTT and colony forming assays and an isogenic MDA-MB-468 TNBC model of PTX resistance. The molecular mechanisms underlying PTX and SMI#9 induced cytotoxicity were determined by flow cytometry, immunoblot analysis of cyclin B1 and microtubule associated protein TAU, and dual immunofluorescence staining of TAU and α-tubulin.ResultsOur data show aberrant centrosome numbers and that PTX sensitivities are not correlated with TNBC BRCA1 status. Combining PTX with SMI#9 synergistically enhances PTX sensitivities of BRCA1 wild-type and mutant TNBC cells. Whereas SMI#9/PTX combination treatment increased cyclin B1 levels in MDA-MB-468 cells, it induced cyclin B1 loss in HCC1937 cells with accumulation of reproductively dead giant cells, a characteristic of mitotic catastrophe. Cell cycle analysis revealed drug-induced accumulation of tetraploid cells in S and G2/M phases, and robust increases in cells with 4 N DNA content in HCC1937 cells. TAU overexpression is associated with reduced PTX efficacy. Among the six TAU isoforms, both SMI#9 and PTX downregulated 1N3R TAU in MDA-MB-468 and HCC1937 cells, suggesting a common mechanism of 1N3R regulation. Dual TAU and α-tubulin immunostaining showed that SMI#9 induces monopolar mitotic spindles. Using the isogenic model of PTX resistance, we show that SMI#9 treatment restores PTX sensitivity.ConclusionsThese data support a common mechanism of microtubule regulation by SMI#9 and PTX and suggest that combining PTX with RAD6 inhibitor may be beneficial for increasing TNBC sensitivities to PTX and alleviating toxicity. This study demonstrates a new role for RAD6 in regulating microtubule dynamics.

Project description:Our study aimed to compare the efficacy and safety of nab-paclitaxel plus cisplatin (AP) with nab-paclitaxel plus gemcitabine (AG) in patients with metastatic breast cancer (MBC). We collected data from two single-arm, phase II MBC studies. In NCT01149798, seventy-three MBC patients received 125 mg/m2 nab-paclitaxel on days 1, 8 and 15 followed by 75 mg/m2 cisplatin on day 1 of a 28-day cycle. In NCT01550848, eighty-four MBC patients received 125 mg/m2 nab-paclitaxel and 800 mg/m2 gemcitabine on days 1, 8, and 15 of a 28-day cycle. The endpoints were the overall response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety profiles of these regimens. Among the 157 patients included, the ORR were 67.1% and 52.4% for the AP and AG arms, respectively (odds ratio [OR] = 0.246; hazard ratio [HR] = 1.485; 95% confidence interval [CI], 0.762-2.985). After median follow-up periods of 26.3 and 23.3 months in the AP and AG arms, the median PFS were 9.8 months (95%CI, 8.1-11.6) and 8.1 months (95%CI, 6.8-9.4), respectively, while the median OS were 26.9 months (95%CI, 22.4-31.4) and 25.5 months (95%CI, 19.3-31.4), respectively. Neither PFS nor OS adjusted for the number of metastases, occurrence of liver metastasis and chemotherapeutic lines differed significantly between the two arms (PFS:HR = 0.769; 95%CI, 0.541-1.092; p = 0.142; OS:HR = 0.686; 95%CI, 0.426-1.104; p = 0.120). However, PFS was significantly better with AP than with AG in metastatic triple-negative breast cancer (mTNBC) patients (HR = 0.308; 95%CI, 0.129-0.732; p = 0.008). Adverse events were more common with AP than with AG, except for edema and myalgia. Both regimens showed substantial efficacy and were tolerated well in MBC patients. mTNBC who received AP rather than AG showed longer PFS. However, adverse events were more common with AP. Thus, AP may be worth recommending to mTNBC, while AG may be a better alternative for MBC patients with other subtypes.

Project description:Immune checkpoint blockade therapy has clearly shown clinical activity in patients with triple-negative breast cancer, but less than half of the patients benefit from the treatments. While a number of ongoing clinical trials are investigating different combinations of checkpoint inhibitors and chemotherapeutic agents, predictive biomarkers that identify patients most likely to benefit remains one of the major challenges. Here we present a modular quantitative systems pharmacology (QSP) platform for immuno-oncology that incorporates detailed mechanisms of immune-cancer cell interactions to make efficacy predictions and identify predictive biomarkers for treatments using atezolizumab and nab-paclitaxel. A QSP model was developed based on published data of triple-negative breast cancer. With the model, we generated a virtual patient cohort to conduct in silico virtual clinical trials and make retrospective analyses of the pivotal IMpassion130 trial that led to the accelerated approval of atezolizumab and nab-paclitaxel for patients with programmed death-ligand 1 (PD-L1) positive triple-negative breast cancer. Available data from clinical trials were used for model calibration and validation. With the calibrated virtual patient cohort based on clinical data from the placebo comparator arm of the IMpassion130 trial, we made efficacy predictions and identified potential predictive biomarkers for the experimental arm of the trial using the proposed QSP model. The model predictions are consistent with clinically reported efficacy endpoints and correlated immune biomarkers. We further performed a series of virtual clinical trials to compare different doses and schedules of the two drugs for simulated therapeutic optimization. This study provides a QSP platform, which can be used to generate virtual patient cohorts and conduct virtual clinical trials. Our findings demonstrate its potential for making efficacy predictions for immunotherapies and chemotherapies, identifying predictive biomarkers, and guiding future clinical trial designs.

Project description:IntroductionIntrinsic or acquired chemoresistance is a major problem in oncology. Although highly responsive to chemotherapies such as paclitaxel, most triple negative breast cancer (TNBC) patients develop chemoresistance. Here we investigate the role of BRCA1-IRIS as a novel treatment target for TNBCs and their paclitaxel-resistant recurrences.MethodsWe analyzed the response of BRCA1-IRIS overexpressing normal mammary cells or established TNBC cells silenced from BRCA1-IRIS to paclitaxel in vitro and in vivo. We analyzed BRCA1-IRIS downstream signaling pathways in relation to paclitaxel treatment. We also analyzed a large cohort of breast tumor samples for BRCA1-IRIS, Forkhead box class O3a (FOXO3a) and survivin expression. Finally, we analyzed the effect of BRCA1-IRIS silencing or inactivation on TNBCs formation, maintenance and response to paclitaxel in an orthotopic model.ResultsWe show that low concentrations of paclitaxel triggers BRCA1-IRIS expression in vitro and in vivo, and that BRCA1-IRIS activates two autocrine signaling loops (epidermal growth factor (EGF)/EGF receptor 1 (EGFR)-EGF receptor 2 (ErbB2) and neurogulin 1 (NRG1)/ErbB2-EGF receptor 3 (ErbB3), which enhances protein kinase B (AKT) and thus survivin expression/activation through promoting FOXO3a degradation. This signaling pathway is intact in TNBCs endogenously overexpressing BRCA1-IRIS. These events trigger the intrinsic and acquired paclitaxel resistance phenotype known for BRCA1-IRIS-overexpressing TNBCs. Inactivating BRCA1-IRIS signaling using a novel inhibitory mimetic peptide inactivates these autocrine loops, AKT and survivin activity/expression, in part by restoring FOXO3a expression, and sensitizes TNBC cells to low paclitaxel concentrations in vitro and in vivo. Finally, we show BRCA1-IRIS and survivin overexpression is correlated with lack of FOXO3a expression in a large cohort of primary tumor samples, and that BRCA1-IRIS overexpression-induced signature is associated with decreased disease free survival in heavily treated estrogen receptor alpha-negative patients.ConclusionsIn addition to driving TNBC tumor formation, BRCA1-IRIS overexpression drives their intrinsic and acquired paclitaxel resistance, partly by activating autocrine signaling loops EGF/EGFR-ErbB2 and NRG1/ErbB2-ErbB3. These loops activate AKT, causing FOXO3a degradation and survivin overexpression. Taken together, this underscores the need for BRCA1-IRIS-specific therapy and strongly suggests that BRCA1-IRIS and/or signaling loops activated by it could be rational therapeutic targets for advanced TNBCs.

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Stress hormones reduce the efficacy of paclitaxel in triple negative breast cancer through induction of DNA damage.

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Stress hormones reduce the efficacy of paclitaxel in triple negative breast cancer through induction of DNA damage.

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