Abstract 16201: Combined Treatment of the PI3k/mTOR Inhibitor BEZ235 With Doxorubicin Does Not Increase Cardiotoxicity While Improving Efficacy in Breast Cancer Cells

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
David E Durrant ◽  
Samya Dyer ◽  
Anindita Das ◽  
Rakesh C Kukreja

Background: Cardiotoxicity is a major clinical limitation with doxorubicin (DOX). Also, the PI3K/Akt survival pathway is one of the most commonly mutated pathways in cancer. Therefore, the combination of kinase inhibitors and chemotherapy, such as DOX, are necessary for achieving cancer control. The PI3K pathway is also critical for protecting the heart from stress. Therefore, we examined the combined effect of BEZ235 (BEZ), a dual PI3k/mTOR inhibitor, with DOX on cardiac function and killing of breast cancer cells. Methods and results: c57 mice were treated with BEZ (40 mg/kg daily oral gavage) and DOX (3 IV injections of 5 mg/kg) either alone or in combination. Systolic function was assessed 12 weeks after initial treatment using echocardiography. Decreased ejection fraction was observed after DOX treatment. Interestingly, the combined treatment with BEZ and DOX did not exacerbate DOX cardiotoxicity (Fig. A). Western blot analysis showed significant increase in AKT (thr 308) and ERK phosphorylation with BEZ and DOX as compared individual treatment with BEZ or DOX in the heart (Fig. B). To address the anti-cancer effects of these drugs, MDA-MB-231 breast cancer cells were treated with BEZ and DOX either alone or in combination for 48 hours. Necrosis, measured using the trypan blue assay, showed a significant increase in dead cells compared to either drug alone (Fig. C). Conclusion: Concurrent treatment with DOX and BEZ did not exacerbate cardiac toxicity as demonstrated by similar level of deficit in ejection fraction between DOX as well as DOX plus BEZ. This could be due to enhanced survival signaling in the combination group. BEZ also sensitized breast cancer cells to DOX resulting in increased cell death. We propose that this combination strategy might lead to improved long term outcomes for patients with breast cancer without additional complications related to cardiac dysfunction.

2020 ◽  
Vol 8 (1) ◽  
pp. e000195 ◽  
Author(s):  
Johannes Laengle ◽  
Julijan Kabiljo ◽  
Leah Hunter ◽  
Jakob Homola ◽  
Sophie Prodinger ◽  
...  

BackgroundThe monoclonal antibody (mAb) trastuzumab is part of the standard of care for patients with human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer. Antibody-dependent cell-mediated phagocytosis (ADCP) and cytotoxicity (ADCC) are major mechanisms of action of the mAb trastuzumab. Histone deacetylase inhibitors (HDACi), such as valproic acid (VPA) or vorinostat (SAHA), exert several immunostimulatory properties, which contribute at least in part to their anticancer effect. However, the impact of HDACi-induced immunostimulatory effects on trastuzumab-mediated anti-tumor immune response is not well characterized.MethodsWe analyzed the ADCP and ADCC activity of peripheral blood mononuclear cells (PBMCs) from age and gender-matched healthy volunteers (n=5) against HDACi-treated HER2-overexpressing breast cancer cells (SKBR3), using a well-established in vitro three-color imaging flow cytometry and flow cytometry approach.ResultsVPA and SAHA enhanced trastuzumab-mediated ADCP and trastuzumab-independent cytotoxicity. Mechanistically, VPA upregulated the activating antibody-binding receptor Fc-gamma receptor (FcγR) IIA (CD32A) on monocytes (CD14+). Moreover, VPA and SAHA downregulated the anti-apoptotic protein myeloid leukemia cell differentiation 1 (MCL1) in breast cancer cells. Additionally, VPA and SAHA induced an immunogenic cell death, characterized by the exposure of calreticulin (CALR), as well as decreased the “do not eat me” signal CD47 on tumor cells.ConclusionsHDACi VPA and SAHA increase trastuzumab-mediated phagocytosis and trastuzumab-independent cytotoxicity. The immunomodulatory activities of those HDACi support a rationale combined treatment approach with mAb for cancer treatment.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14565-e14565
Author(s):  
D. Sharma ◽  
B. B. Knight ◽  
R. Yacoub ◽  
T. Liu ◽  
L. Taliaferro-Smith ◽  
...  

e14565 Background: The outcome for patients with breast cancer has been significantly improved by the use of targeted agents. The prognosis of triple negative (TN) breast cancers, which do not express hormone receptors (ER, PR) or Her2, is poor, because of an aggressive clinical course and lack of targeted therapeutic agents. Epigenetic silencing of specific genes has been observed in breast cancer and some of these genes are more important due to available targeted therapies such as ER. Since all endocrine therapies are designed to block ER function in some way, the identification of new therapies or strategies that could sensitize TN breast cancers to existing endocrine therapy could provide a revolutionary means of treating this aggressive subtype of cancer Methods: We examined the efficacy of combined treatment of HDAC inhibitor LBH589 and DNMT inhibitor decitabine to regenerate ER and PR in TN breast cancer cells using RT-PCR and immunoblotting. Changes in growth and proliferation of TN breast cancer cells in response to LBH589 and decitabine treatment were determined by XTT, BrdU incorporation and colony formation assay. Changes in apoptotic proteins were determined by western blotting. Athymic nude mice were used to establish pre-clinical models for TN breast cancer cells and effectiveness of combined treatment of LBH589 and decitabine was determined. Tumors biopsies were analyzed for ER and PR re-expression by western blot analysis and immunohistochemistry at the end of the treatment. Results: Combined treatment of LBH589 and decitabine resulted in re-expression of ER and PR in TN breast cancers in vitro and in vivo. Although re-expression of ER and PR were noted following LBH589 treatment alone, re-expression was more robust with the combination. TN breast cancer cells showing re-expressed ER can be targeted with tamoxifen. Tamoxifen inhibits growth of TN breast cancer cells re- expressing ER by triggering apoptosis. Conclusions: The importance of epigenetic events such as DNA methylation and HDAC inhibition in tumor progression is becoming increasingly evident. A trial evaluating the ability of LBH589 and decitabine to re- express ER, which can then be targeted by tamoxifen, is planned in patients with metastatic TN breast cancer. No significant financial relationships to disclose.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Maruša Bizjak ◽  
Petra Malavašič ◽  
Klemen Dolinar ◽  
Jelka Pohar ◽  
Sergej Pirkmajer ◽  
...  

2009 ◽  
Vol 106 (52) ◽  
pp. 22299-22304 ◽  
Author(s):  
Saskia M. Brachmann ◽  
Irmgard Hofmann ◽  
Christian Schnell ◽  
Christine Fritsch ◽  
Susan Wee ◽  
...  

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