New Therapies For Breast Cancer Research Articles

Mesenchymal Stem Cell-Secreted Extracellular Vesicles Instruct Stepwise Dedifferentiation of Breast Cancer Cells into Dormancy at the Bone Marrow Perivascular Region.

In the bone marrow (BM), breast cancer cells (BCC) can survive in dormancy for decades as cancer stem cells (CSC), resurging as tertiary metastasis. The endosteal region where BCCs exist as CSCs poses a challenge to target them, mostly due to the coexistence of endogenous hematopoietic stem cells. This study addresses the early period of dormancy when BCCs enter BM at the perivascular region to begin the transition into CSCs, which we propose as the final step in dormancy. A two-step process comprises the Wnt-β-catenin pathway mediating BCC dedifferentiation into CSCs at the BM perivascular niche. At this site, BCCs responded to two types of mesenchymal stem cell (MSC)-released extracellular vesicles (EV) that may include exosomes. Early released EVs began the transition into cycling quiescence, DNA repair, and reorganization into distinct BCC subsets. After contact with breast cancer, the content of EVs changed (primed) to complete dedifferentiation into a more homogeneous population with CSC properties. BCC progenitors (Oct4alo), which are distant from CSCs in a hierarchical stratification, were sensitive to MSC EVs. Despite CSC function, Oct4alo BCCs expressed multipotent pathways similar to CSCs. Oct4alo BCCs dedifferentiated and colocalized with MSCs (murine and human BM) in vivo. Overall, these findings elucidate a mechanism of early dormancy at the BM perivascular region and provide evidence of epigenome reorganization as a potential new therapy for breast cancer. SIGNIFICANCE: These findings describe how the initial process of dormancy and dedifferentiation of breast cancer cells at the bone marrow perivascular niche requires mesenchymal stem cell-derived exosomes, indicating a potential target for therapeutic intervention.

Transcriptome-based identification of lovastatin as a breast cancer stem cell-targeting drug.

Breast cancer is a neoplastic disease with high morbidity and mortality in women worldwide. Breast cancer stem cells (CSCs) have a significant function in tumor growth, recurrence, and therapeutic resistance. Thus, CSCs have been pointed as targets of new therapies for breast cancer. Herein, we aimed to repurpose certain drugs as breast CSC-targeting agents. We compared a consensus breast CSC signature with the transcriptomic changes that were induced by over 1300 bioactive compounds using Connectivity Map. The effects of the selected drugs on SOX2 promoter transactivation, SOX2 expression, viability, clonogenicity, and ALDH activity in breast cancer cells were analyzed by luciferase assay, western blot, MTT assay, mammosphere formation assay, and ALDEFLUOR® test, respectively. Gene Set Enrichment Analysis (GSEA) was performed using the gene expression data from mammary tumors of mice that were treated with lovastatin. Five drugs (fasudil, pivmecillinam, ursolic acid, 16,16-dimethylprostaglandin E2, and lovastatin) induced signatures that correlated negatively with the query CSC signature. In vitro, lovastatin inhibited SOX2 promoter transactivation, and reduced the efficiency of mammosphere formation and the percentage of ALDH+ cells. Mevalonate mitigated the effects of lovastatin, suggesting that the targeting of CSCs by lovastatin was mediated by the inhibition of its reported target, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR). By GSEA, lovastatin downregulated genes that are involved in stemness and invasiveness in mammary tumors, corroborating our in vitro findings. Lovastatin is a breast CSC-targeting drug. The inhibition of HMGCR might develop new adjuvant therapeutic strategies for breast tumors.

A Digital RNA Signature of Circulating Tumor Cells Predicting Early Therapeutic Response in Localized and Metastatic Breast Cancer.

The multiplicity of new therapies for breast cancer presents a challenge for treatment selection. We describe a 17-gene digital signature of breast circulating tumor cell (CTC)-derived transcripts enriched from blood, enabling high-sensitivity early monitoring of response. In a prospective cohort of localized breast cancer, an elevated CTC score after three cycles of neoadjuvant therapy is associated with residual disease at surgery (P = 0.047). In a second prospective cohort with metastatic breast cancer, baseline CTC score correlates with overall survival (P = 0.02), as does persistent CTC signal after 4 weeks of treatment (P = 0.01). In the subset with estrogen receptor (ER)-positive disease, failure to suppress ER signaling within CTCs after 3 weeks of endocrine therapy predicts early progression (P = 0.008). Drug-refractory ER signaling within CTCs overlaps partially with presence of ESR1 mutations, pointing to diverse mechanisms of acquired endocrine drug resistance. Thus, CTC-derived digital RNA signatures enable noninvasive pharmacodynamic measurements to inform therapy in breast cancer.Significance: Digital analysis of RNA from CTCs interrogates treatment responses of both localized and metastatic breast cancer. Quantifying CTC-derived ER signaling during treatment identifies patients failing to respond to ER suppression despite having functional ESR1. Thus, noninvasive scoring of CTC-RNA signatures may help guide therapeutic choices in localized and advanced breast cancer. Cancer Discov; 8(10); 1286-99. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1195.

Abstract P2-04-04: Developing targeted therapeutic microbubbles for enhanced epigenetic drug delivery for breast cancer

Abstract Background: In recent years, there has been great interest in developing drugs that modify epigenetic changes as new therapies for breast cancer (BC). There is evidence that aberrant epigenetic inactivation of genes, essential for normal cell growth, is involved in cancer. These modifications are potentially reversible therefore re-activation of genes in response to epigenetic drugs can result in inhibition of tumour growth or sensitisation to other anti-cancer therapies. Epigenetic drugs are in clinical trials for BC but have some drawbacks: while some can be highly effective in vitro, their poor stability could compromise their clinical use. Also, high doses required to induce an effect in patients could increase off-site toxicity. As a result there is an urgent need to develop novel systems for the delivery and release of these drugs. Objectives: Our aim is to develop targeted microbubbles (MBs) to enhance therapeutic effects in vitro and in vivo. Ultrasound (US)-mediated drug delivery using MBs is proposed as a non-invasive approach for localised drug administration. Methods: We developed assays using low doses of a DNA methyltransferase inhibitor, called decitabine (DAC), for determining its delivery and effect in vitro and in vivo. VEGFR2 was assessed as a targeting molecule for therapeutic delivery to tumour vasculature in vitro and in a human BC xenograft model. We have generated therapeutic MBs with DAC using a flow-focussing microfluidic platform and conducted in vitro and currently performing in vivo studies to observe tumour and tissue responses. Results: Treatment of triple-negative BC (TNBC) cells with low DAC doses revealed restoration of epigenetically dysregulated tumour suppressor genes. These genes were used as biomarkers for the assessment of DAC effects in a human TNBC mouse model. To evaluate the use of a targeting molecule for drug delivery, specific binding of VEGFR2-targeted MBs on VEGFR2+ve mouse endothelial cells was verified by a flow assay. VEGFR2 expression was assessed longitudinally in xenograft tissue and demonstrated significantly higher VEGFR2 expression in the vasculature of smaller size tumours, indicating the time that delivery of targeted MBs would be most effective. DAC-loaded liposomes or co-administration of DAC and MBs in combination with US using a specifically designed US transducer, were tested in vitro. Currently, investigation of the potential of US-triggered drug delivery enhancing efficacy of DAC in vivo is being carried out. In addition, combination treatments have been performed in vitro, showing increased sensitisation of cells to anthracycline treatment after priming with DAC. Conclusions: It may be feasible to combine US, MBs and epigenetic therapy in a pre-clinical setting to improve drug efficacy, particularly for drugs that are rapidly degraded within the body. MB delivery may have the potential to reduce the dosage required, thus reducing off-site side effects in patients. Citation Format: Alataki A, Abou-Saleh R, McLaughlan JR, Markham AF, Evans SD, Coletta PL, Valleley EM. Developing targeted therapeutic microbubbles for enhanced epigenetic drug delivery for breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-04-04.

Distinct expression of CDCA3, CDCA5, and CDCA8 leads to shorter relapse free survival in breast cancer patient.

Breast cancer is a dangerous disease that results in high mortality rates for cancer patients. Many methods have been developed for the treatment and prevention of this disease. Determining the expression patterns of certain target genes in specific subtypes of breast cancer is important for developing new therapies for breast cancer. In the present study, we performed a holistic approach to screening the mRNA expression of six members of the cell division cycle-associated gene family (CDCA) with a focus on breast cancer using the Oncomine and The Cancer Cell Line Encyclopedia (CCLE) databases. Furthermore, Gene Expression-Based Outcome for Breast Cancer Online (GOBO) was also used to deeply mine the expression of each CDCA gene in clinical breast cancer tissue and breast cancer cell lines. Finally, the mRNA expression of the CDCA genes as related to breast cancer patient survival were analyzed using a Kaplan-Meier plot. CDCA3, CDCA5, and CDCA8 mRNA expression levels were significantly higher than the control sample in both clinical tumor sample and cancer cell lines. These highly expressed genes in the tumors of breast cancer patients dramatically reduced patient survival. The interaction network of CDCA3, CDCA5, and CDCA8 with their co-expressed genes also revealed that CDCA3 expression was highly correlated with cell cycle related genes such as CCNB2, CDC20, CDKN3, and CCNB1. CDCA5 expression was correlated with BUB1 and TRIP13, while CDCA8 expression was correlated with BUB1 and CCNB1. Altogether, these findings suggested CDCA3, CDCA5, and CDCA8 could have a high potency as targeted breast cancer therapies.

Evaluation of the Anticancer Activities of the Plant Alkaloids Sanguinarine and Chelerythrine in Human Breast Adenocarcinoma Cells.

Breast cancer is associated with a high mortality rate around the world due to its aggressiveness and high resistance to conventional therapies. Sanguinarine (SAN) and Chelerythrine (CHE) are plant alkaloids extracted from Sanguinaria canadensis and Macleaya cordata, which have been studied for their bioactivities. To determine the anticancer activities of Sanguinarine (SAN) and Chelerythrine (CHE) plant alkaloids. The MTT assay, the alkaline comet assay and cell cycle analyses by flow cytometry were performed. It was observed that SAN was cytotoxic to human breast adenocarcinoma cells (MCF-7) at concentrations of 7.5 µM (24 and 48 hours), effectively reducing cell viability from the concentration of 10 µM for 24 hours and 7.5 µM for 48 hours, by the MTT test. CHE, in turn, was cytotoxic at concentrations of 10 and 20 µM (48 hours), but did not compromise the cellular viability. The comet assay indicated that SAN was genotoxic to the MCF-7 cells, with a significant increment of damage at 10 µM, while none of the tested concentrations of CHE showed a genotoxic effect. The flow cytometry analysis indicated that no cell cycle arrest was caused by both alkaloids, but SAN 10 µM induced a sub-G1 cell population. The results of cytotoxicity, genotoxicity and cell cycle monitoring that are presented in this paper have suggested that SAN has more of a chemotherapeutic activity, as well as having the potential for the development of new therapies for breast cancer, when compared to CHE.

Crosstalk between the vitamin D receptor (VDR) and miR-214 in regulating SuFu, a hedgehog pathway inhibitor in breast cancer cells

The vitamin D receptor (VDR), and its ligand 1α,25-dihydroxyvitamin D3 (1,25D3) prevent breast cancer development and progression, yet the molecular mechanisms governing this are unclear. MicroRNAs (miRNAs) on the other hand, promote or inhibit breast cancer growth. To understand how VDR regulates miRNAs, we compared miRNA expression of wild-type (WT) and VDR knockout (VDRKO) breast cancer cells by a Mouse Breast Cancer miRNA PCR array. Compared to VDR WT cells, expressions of miR-214, miR-199a-3p and miR-199a-5p of the miR-199a/miR-214 cluster were 42, 15, and 10 fold higher in VDRKO cells respectively. Overexpression of VDR in breast cancer cells reduced the miR-199a/miR-214 cluster expression by 30%. VDR status also negatively correlated with Dnm3os expression, a non-coding RNA transcript of the dynamin-3 gene encoding the miR-199a/miR-214 cluster, suggesting that VDR represses this cluster through Dnm3os. Conversely, overexpression of miR-214 in MCF-7 and T47D cells antagonized VDR mediated signaling. Furthermore, there was a positive correlation between VDR status and the expression of Suppressor of fused gene (SuFu), a hedgehog pathway inhibitor. miR-214 on the other hand suppressed SuFu protein expression. These findings suggest a crosstalk between VDR and miR-214 in regulating hedgehog signaling in breast cancer cells, providing new therapies for breast cancer.

Establishment and characterization of a receptor-negative, hormone-nonresponsive breast cancer cell line from an Iraqi patient.

A new breast cancer cell line (AMJ13) has been established from an Iraqi breast cancer patient. It is considered unique because it is the first for an Iraqi population, and is expected to be a useful tool in breast cancer research. The AMJ13 cell line was established from the primary tumor of a 70-year-old Iraqi woman with a histological diagnosis of infiltrating ductal carcinoma. The cells were morphologically characterized by light and scanning electron microscopy, and found to be elongated multipolar epithelial-like cells with a population doubling time of 22 hours. The anchorage-independent growth ability test showed that the cells were able to grow in semisolid agarose, confirming their transformed nature. Cytogenetic study of these cells showed chromosomal aberrations with many structural and numerical abnormalities, producing chromosomes of unknown origin called marker chromosomes. Immunocytochemistry showed that the estrogen receptor and the progesterone receptor were not expressed, and a weak positive result was found for HER2/neu gene expression. AMJ13 cells were positive for BRCA1 and BRCA2, as well as for vimentin. This cell line should be useful when testing new therapies for breast cancer in the Middle East.

Abstract IA26: Regulation of metastasis in breast cancer

Abstract Breast cancer patients with metastatic disease have poor prognoses. A key transcription factor, the loss of GATA3 by mutation or loss of expression correlates with a worse prognosis. Indeed, GATA3 is the third most mutated gene in breast cancer progression. In mouse and human breast cancer cells, GATA3 suppresses metastasis by promoting tumor cell differentiation and by altering the tumor microenvironment. Although GATA3 has many direct targets, one major pathway downstream of GATA3 regulating metastasis is through its induction of miR29 expression. miR29b is enriched in luminal breast cancers, which are high in GATA3. miR29b inhibits metastasis directly by targeting a network of pro-metastatic regulators involved in angiogenesis, collagen remodeling and proteolysis. Loss of miR29b, even in GATA3-expressing cells increases metastasis and promotes a mesenchymal phenotype. That inhibiting metastasis by regulating tumor microenvironmental genes through a GATA3-miR29b axis opens up potentially new therapies for breast cancer. (Supported by Grant R01 CA129523). Citation Format: Zena Werb. Regulation of metastasis in breast cancer. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr IA26.

CTCs hemodialysis: Can it be a new therapy for breast cancer?

Circulating tumor cells (CTCs) play an important role in Blood-borne distant metastasis, which is the leading cause of cancer-related death in breast cancer. So far, the impacts of CTCs as a tool for predicting or monitoring the efficacy of systemic therapy and that it is a independent prognostic factor have been confirmed. However, CTCs cannot be generally removed at primary surgery or by systemic therapy. In some EMT (epithelial mesenchymal transition)-related treatment fail, CTCs can be accumulated in the postoperative course of the patient which lead to a bad prognosis. In view of these, considering mature hemodialysis technology, we further propose CTCs hemodialysis (CHD), which filtrate CTCs out of blood, as a new therapy for the breast cancer.

Breast Cancer in the Asia–Pacific Region

Breast Cancer in the Asia–Pacific Region

Can we afford the future: effectiveness or cost-effectiveness as the criterion for introducing new therapies for breast cancer?

The development of new cytotoxic and biological agents has brought a welcome extension in the range of therapeutic options available to women with both early-stage and advanced breast cancer. Among the most significant recent developments has been the recognition of HER2 as a prognostic factor and target for treatment. In a series of meetings across Europe, 230 experienced oncologists and an expert faculty discussed and voted on how best to treat five women whose cases were chosen to bring out important issues in treatment. In most cases, a range of options were considered appropriate, and intriguing differences emerged between countries in the choices preferred. The following represents a very abbreviated outline of the cases and the management decisions made. Case 1, symptomatic, visceral, metastatic disease overexpressing HER2: most favoured option, trastuzumab plus docetaxel. Case 2, adjuvant chemotherapy in high-risk, hormone-negative, HER2-positive disease: favoured option, FEC-100 for three cycles, followed by three cycles of docetaxel (trastuzumab also given). Case 3, adjuvant endocrine therapy in a postmenopausal woman with hormone-positive, HER2-negative disease: favoured option, tamoxifen for two years followed by aromatase inhibitor (either exemestane or anastrozole). Case 4, inflammatory HER2-positive breast cancer progressing on FEC-100: favoured option, switch to a taxane plus trastuzumab. Case 5, a young woman with hormone-negative, HER2-positive disease who develops symptomatic visceral metastases a year after adjuvant FEC-100 and trastuzumab: favoured option, enrollment in a clinical trial of the HER2 tyrosine kinase inhibitor lapatinib alone or in combination with trastuzumab or chemotherapy. Together, the expression of these preferences and the discussions that followed provide a valuable insight into current practice at a time of exceptionally rapid change in the management of breast cancer.

395 POSTER CpG island methylator phenotype (CIMP): a novel biomaker to predict new therapy for breast cancer

395 POSTER CpG island methylator phenotype (CIMP): a novel biomaker to predict new therapy for breast cancer

Patterns of trastuzumab (T) use in three Canadian provinces

633 Background: New therapies for breast cancer are not always readily and appropriately adopted in clinical practice. The objective of this study was to examine patterns of T use in three Canadian provinces: Ontario (ON), Quebec (QC) and British Columbia (BC). While all 3 provinces have publicly funded health care systems, the care delivery models are different. ON has a centralized cancer system with the use of evidence based guidelines and the requirement for completion of new drug eligibility forms. BC has a more centralized system with less restrictive guidelines and implementation requirements. QC has none of these factors. In 1999 the federal regulatory agency approved T for use as a single agent or combined with chemotherapy in HER 2 positive metastatic breast cancer (MBC). ON and BC guidelines recommended T for use in combination with paclitaxel (P) or vinorelbine (V) (the latter in BC only) after anthracycline failure or as a single agent after taxane failure. Methods: Case specific data were collected on all patients treated with T for 3 years from 1999–2002. Patients on a T clinical trial were excluded. Information was collected from provincial cancer registries and patient charts. Patients were evaluated for consistency with federal agency recommendations and provincial guidelines. Results: T was used in 398 women in ON; 322 in QC; and 205 in BC representing respectively 6.6%; 7.4% and 10.7% of the estimated number of women who died of MBC in those provinces during the study period. Patients in ON and BC were more likely to be treated consistent with federal agency recommendations and provincial guidelines (Table). Response rates were higher in BC which was associated with earlier use in patients with fewer sites of MBC and less prior treatment. Conclusions: The presence of a centralized cancer system led to better adherence to federal agency recommendations. Less restrictive guidelines may facilitate earlier use of T. No significant financial relationships to disclose.

Patterns of trastuzumab (T) use in three Canadian provinces

633 Background: New therapies for breast cancer are not always readily and appropriately adopted in clinical practice. The objective of this study was to examine patterns of T use in three Canadian provinces: Ontario (ON), Quebec (QC) and British Columbia (BC). While all 3 provinces have publicly funded health care systems, the care delivery models are different. ON has a centralized cancer system with the use of evidence based guidelines and the requirement for completion of new drug eligibility forms. BC has a more centralized system with less restrictive guidelines and implementation requirements. QC has none of these factors. In 1999 the federal regulatory agency approved T for use as a single agent or combined with chemotherapy in HER 2 positive metastatic breast cancer (MBC). ON and BC guidelines recommended T for use in combination with paclitaxel (P) or vinorelbine (V) (the latter in BC only) after anthracycline failure or as a single agent after taxane failure. Methods: Case specific data were collected on all patients treated with T for 3 years from 1999–2002. Patients on a T clinical trial were excluded. Information was collected from provincial cancer registries and patient charts. Patients were evaluated for consistency with federal agency recommendations and provincial guidelines. Results: T was used in 398 women in ON; 322 in QC; and 205 in BC representing respectively 6.6%; 7.4% and 10.7% of the estimated number of women who died of MBC in those provinces during the study period. Patients in ON and BC were more likely to be treated consistent with federal agency recommendations and provincial guidelines (Table). Response rates were higher in BC which was associated with earlier use in patients with fewer sites of MBC and less prior treatment. Conclusions: The presence of a centralized cancer system led to better adherence to federal agency recommendations. Less restrictive guidelines may facilitate earlier use of T. No significant financial relationships to disclose.

New approaches in the therapy of breast cancer--introduction.

Interaction of academic medical research centers with the pharmaceutical and biotechnology industries is essential for progress in exploring new avenues for therapy of breast cancer. This special issue of Breast Cancer Research and Treatment reports the proceedings of a conference held by the Lombardi Cancer Center, Georgetown University, on progress toward development of new therapies for breast cancer. These chapters are organized to present the following topics: immunotherapy, tumor growth pathways and their inhibition, and tumor-host interaction pathways and their inhibition.