Clinical Treatment Of Breast Cancer Research Articles

Reactivation of tumour suppressor in breast cancer by enhancer switching through NamiRNA network

Dysfunction of Tumour Suppressor Genes (TSGs) is a common feature in carcinogenesis. Epigenetic abnormalities including DNA hypermethylation or aberrant histone modifications in promoter regions have been described for interpreting TSG inactivation. However, in many instances, how TSGs are silenced in tumours are largely unknown. Given that miRNA with low expression in tumours is another recognized signature, we hypothesize that low expression of miRNA may reduce the activity of TSG related enhancers and further lead to inactivation of TSG during cancer development. Here, we reported that low expression of miRNA in cancer as a recognized signature leads to loss of function of TSGs in breast cancer. In 157 paired breast cancer and adjacent normal samples, tumour suppressor gene GPER1 and miR-339 are both downregulated in Luminal A/B and Triple Negative Breast Cancer subtypes. Mechanistic investigations revealed that miR-339 upregulates GPER1 expression in breast cancer cells by switching on the GPER1 enhancer, which can be blocked by enhancer deletion through the CRISPR/Cas9 system. Collectively, our findings reveal novel mechanistic insights into TSG dysfunction in cancer development, and provide evidence that reactivation of TSG by enhancer switching may be a promising alternative strategy for clinical breast cancer treatment.

Co-delivery of Pirarubicin and Vinorelbine by Micelles for the Treatment of Breast Cancer

To develop a pirarubicin (THP) and vinorelbine (VRL) codelivery nano-micellar system (T+V-CS micelles) of pirarubicin (THP) and vinorelbine (VRL) by using chondroitin sulfate-cholesterol polymers (CS-Chol) and DSPE-mPEG 2000 and to evaluate the therapeutic efficacy of the codelivery nano-micelles in breast cancer treatment. T+V-CS micelles were prepared by ultrasonic-dialysis method, and the physicochemical characterization were evaluated using multiple technological means. The anti-tumor efficacy of T+V-CS micelles in vitro was evaluated by MTT assay and cell cycle arrest analysis. Evaluation of the therapeutic effect of T+V-CS micelles in vivo was carried out on xenograft 4T1 murine breast cancer bearing BALB/c mice model. T+V-CS micelles displayed a nearly spherical shape when observed through transmission electron microscope. The particle size and polydispersity indexes (PDI) of T+V-CS micelles was (155.5±4.5) nm and 0.170±0.003 respectively, while the Zeta potential was (-23.0±0.9) mV. Meanwhile, T+V-CS micelles demonstrated high encapsulation efficiency of (81.87±2.56)% for THP and (87.54±2.82)% for VRL and a high overall drug loading efficiency of (10.20±1.20)%. In vitro and in vivo studies of the therapeutic efficacy of breast cancer showed that T+V-CS micelles had synergistic anti-tumor effect and induced increased G 2/M cell cycle arrest in 4T1 cells, which could significantly inhibit tumor growth and prolong survival compared with the therapeutic efficacy of micelles loaded with a single kind of drug or free drug solutions. The study showed that T+V-CS micelles had excellent anti-tumor effect, offering a reference to the clinical treatment of breast cancer.

Persistent Metabolic Effects of Tamoxifen: Considerations for an Experimental Tool and Clinical Breast Cancer Treatment.

The selective estrogen receptor (ER) modulator tamoxifen is frequently used in preclinical studies to induce Cre recombinase and generate conditional transgenic mice. In addition, it is often prescribed to treat ER-positive breast cancer, which is diagnosed in approximately 150 000 people each year. In mice, protocols to activate Cre-ER transgenes require tamoxifen administration by several methods, including oral gavage, IP injection, or intragastric injection, spanning a wide range of doses to achieve transgene induction. As a result, the reported metabolic effects of tamoxifen treatment are not always consistent with anecdotal reports from breast cancer patients, or with expected outcomes based on the overall metabolically protective role of estrogen. A greater awareness of tamoxifen’s adverse metabolic effects is critical to designing studies with appropriate controls, especially those investigations focused on metabolic outcomes.

Dimer Targeting Peptide Mediated Precise and Controllable Drug Delivery by Upconversion Nanocarriers for Breast Cancer Therapy

Breast cancer is one of the leading causes of cancer-related deaths in women. Chemotherapy remains one of the main clinical treatments for breast cancer. However, this therapy has appreciable side effects. Nanoscale carriers, such as metal nanoparticles and liposomes, are being widely utilized as drug delivery vehicles to achieve precise targeting of tumor cells. In this study, we designed a novel up conversion nanocarriers (UCNCs) host-guest complexation system based on a photolabile capping-like molecule. UCNCs containing epirubicin (EPI) were grafted with a dimer-targeting peptide via cyclodextrin-adamantine host-guest complexation. After entering breast tumor cells with the guidance of the dimer-targeting peptide, the core of the UCNCs upconverted near-infrared light to ultraviolet light which subsequently triggered the intracellular on-demand release of epirubicin. The precise and efficient delivery and release of epirubicin inside breast cancer cells significantly inhibited cancer cells proliferation, migration, and invasion in vitro and decreased the tumor size in vivo. We believe that this UCNCs system is a promising platform for the precise and controllable delivery of various chemotherapy drugs for clinical cancer treatments.

Dimer targeting peptide mediated precise and controllable drug delivery by upconversion nanocarriers for breast cancer therapy

Breast cancer is one of the leading causes of cancer-related deaths in women. Chemotherapy remains one of the main clinical treatments for breast cancer. However, this therapy has appreciable side effects. Nanoscale carriers, such as metal nanoparticles and liposomes, are being widely utilized as drug delivery vehicles to achieve precise targeting of tumor cells. In this study, we designed a novel upconversion nanocarriers (UCNCs) host-guest complexation system based on a photolabile capping-like molecule. UCNCs containing epirubicin (EPI) were grafted with a dimer-targeting peptide via cyclodextrin-adamantine host-guest complexation. After entering breast tumor cells with the guidance of the dimer-targeting peptide, the core of the UCNCs upconverted near-infrared light to ultraviolet light which subsequently triggered the intracellular on-demand release of epirubicin. The precise and efficient delivery and release of epirubicin inside breast cancer cells significantly inhibited cancer cells proliferation, migration, and invasion in vitro and decreased the tumor size in vivo. We believe that this UCNCs system is a promising platform for the precise and controllable delivery of various chemotherapy drugs for clinical cancer treatments.

Prognostic and predictive parameters in breast pathology: a pathologist's primer

The pathologist's role in the breast cancer treatment team has evolved from rendering a diagnosis of breast cancer, to providing a growing list of prognostic and predictive parameters such that individualized treatment decisions can be made based on likelihood of benefit from additional treatments and potential benefit from specific therapies. In all stages, ER and HER2 status help segregate breast cancers into treatment groups with similar outcomes and treatment response rates, however, traditional pathologic parameters such as favorable histologic subtype, size, lymph node status, and Nottingham grade also have remained clinically relevant in early stage disease decision-making. This is especially true for the most common subtype of breast cancer; ER positive, HER2 negative disease. For this same group of breast cancers, an ever-expanding list of gene-expression panels also can provide prediction and prognostication about potential chemotherapy benefit beyond standard endocrine therapies, with the 21-gene Recurrence Score, currently the only prospectively validated predictive test for this purpose. In the more aggressive ER-negative cancer subtypes, response to neoadjuvant therapy and` the extent of tumor infiltrating lymphocytes (TILs) are more recently recognized powerful prognostic parameters, and clinical guidelines now offer additional treatment options for those high-risk patients with residual cancer after standard neoadjuvant therapy. In stage four disease, predictive tests like germline BRCA status, tumor PIK3CA mutation status (in ER+ metastatic disease) and PDL-1 status (in triple negative metastatic disease) are now used to determine additional new treatment options. The objective of this review is to describe the latest in prognostic and predictive parameters in breast cancer as they are relevant to standard pathology reporting and how they are used in breast cancer clinical treatment decisions.

Design and Synthesis of Multi-Functional Superparamagnetic Core-Gold Shell Coated with Chitosan and Folate Nanoparticles for Targeted Antitumor Therapy.

A dual-targeting nanomedicine composed of pH-sensitive superparamagnetic iron oxide core-gold shell SPION@Au, chitosan (CS), and folate (FA) was developed as a doxorubicin (DOX) antitumor medication. Microemulsion was used for preparation and cross-linking conjugation. The characteristics of the designed nanocomposite were studied using atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction, UV-visible spectroscopy, Zeta potential and vibrating sample magnetometry (VSM), and Fourier transform infrared spectroscopy. The prepared SPION@Au-CS-DOX-FA nanoparticles (NPs) were spherical with an average diameter of 102.6 ± 7 nm and displayed an elevated drug loading behavior and sustained drug release capacity. The SPION@Au-CS-DOX-FA NPs revealed long term anti-cancer efficacy due to their cytotoxic effect and apoptotic inducing efficiency in SkBr3 cell lines. Additionally, Real-time PCR outcomes significantly showed an increase in BAK and BAX expression and a decrease in BCL-XL and BCL-2. In vivo results revealed that SPION@Au significantly decreased the tumor size in treated mice through magnetization. In conclusion, prepared SPION@Au-CS-DOX-FA could be a beneficial drug formulation for clinical breast cancer treatment.

Progress in the Understanding of the Mechanism of Tamoxifen Resistance in Breast Cancer.

Tamoxifen is a drug commonly used in the treatment of breast cancer, especially for postmenopausal patients. However, its efficacy is limited by the development of drug resistance. Downregulation of estrogen receptor alpha (ERα) is an important mechanism of tamoxifen resistance. In recent years, with progress in research into the protective autophagy of drug-resistant cells and cell cycle regulators, major breakthroughs have been made in research on tamoxifen resistance. For a better understanding of the mechanism of tamoxifen resistance, protective autophagy, cell cycle regulators, and some transcription factors and enzymes regulating the expression of the estrogen receptor are summarized in this review. In addition, recent progress in reducing resistance to tamoxifen is reviewed. Finally, we discuss the possible research directions into tamoxifen resistance in the future to provide assistance for the clinical treatment of breast cancer.

Abemaciclib-Based Combinational Therapies to Overcome Therapeutic Resistance in Mantle Cell Lymphoma

Introduction The past decades witnessed dramatic improvement of overall survival rate of mantle cell lymphoma (MCL) patients by constant efforts in developing novel therapeutic strategies that include ibrutinib and venetoclax. Nevertheless, resistance is still a major challenge in refractory/relapsed MCL patients. Chromosomal translocation t(11:14)(q13:q32) of the cyclin D1 (CCND1) gene is the hallmark of MCL, which leads to overexpression of cyclin D1. This overexpression promotes aberrant cell cycle progression by activating CDK4/6. Abemaciclib is a selective CDK4/6 inhibitor used as a clinical treatment of breast cancer and has been shown to be effective in preclinical human MCL xenograft models. It has also been used in a phase II clinical trial as a single agent among refractory/relapsed MCL patients with an objective response rate of 35.7%. In this preclinical study, we aim to evaluate the benefit of a combinational therapeutic strategy using abemaciclib with other molecular targeting agents among MCL patients with therapeutic resistance. Methods Cytotoxic efficacy of abemaciclib as a single agent and in combination with other drugs on different MCL cell lines and primary lymphoma cells from MCL patients with or without resistance was used as a key criterion for screening beneficial therapeutic strategies. Cell apoptosis and cell cycle arrest assays were conducted to further evaluate those effective combinations. Western blot was performed to investigate the mechanism of action of the combinations. Finally, the efficacy of abemaciclib alone or in combination were assessed in ibrutinib-resistant or venetoclax-resistant MCL PDX models in vivo. Results Our preliminary data showed that all MCL cell lines involved in this study were highly sensitive to abemaciclib treatment with IC50 values ranging from 50 nM to 1 µM. Further investigation of abemaciclib cytotoxicity on ibrutinib and/or venetoclax resistant MCL cell lines showed effective inhibition with a higher IC50 values ranging from 5 µM to 10 µM. More importantly, abemaciclib had potent efficacy on cells from primary MCL patients as well as from patients with acquired ibrutinib resistance. Our recent findings revealed that the addition of PI3K inhibitor TGR-1202 significantly enhanced cytotoxicity of abemaciclib in both sensitive and resistant MCL cell lines. Abemaciclib significantly inhibited phosphorylation of Rb1, the active form of the protein, in 4 different MCL cell lines. The active Rb1 maintains the cell in the G1 phase, preventing progression through the cell cycle and acting as a growth suppressor. The result suggests that CDK4/6 inhibition with abemaciclib disrupts CDK4/6 suppressive activity towards pRb-E2F and induce cell cycle arrest in the MCL cells. Interestingly, abemaciclib somehow interrupted phosphorylation of Chk1, which is continuously phosphorylated and hence activated in the MCL cell lines. Inhibiting activation of Chk1 by abemaciclib may induce cell death via unmonitored and accumulated DNA damage. The efficacy of abemaciclib in combination with Bcl-2 or BTK inhibitors in MCL cell lines and isolated cells from MCL patients are ongoing. These data suggest that abemaciclib in combination with other therapeutic drugs could be beneficial in targeting therapeutic resistant MCL cells. Conclusions Abemaciclib showed impressive therapeutic potency on both MCL cell lines and isolated primary cells from MCL patients, which is likely due to the predominant contribution of cyclin D1-CDK4/6 pathway to malignancy. Other agents, such as PI3K inhibitors, can sensitize abemaciclib in therapeutic resistant MCL cells. Thus, an abemaciclib based multi-drug combinational strategy may be a promising therapy for refractory/relapsed MCL patients in the near future. Disclosures Wang: Beijing Medical Award Foundation: Honoraria; Lu Daopei Medical Group: Honoraria; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Pulse Biosciences: Consultancy; Loxo Oncology: Consultancy, Research Funding; Targeted Oncology: Honoraria; OMI: Honoraria, Other: Travel, accommodation, expenses; Nobel Insights: Consultancy; Guidepoint Global: Consultancy; Dava Oncology: Honoraria; Verastem: Research Funding; Molecular Templates: Research Funding; OncLive: Honoraria; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Oncternal: Consultancy, Research Funding; Juno: Consultancy, Research Funding; BioInvent: Research Funding; VelosBio: Research Funding; Acerta Pharma: Research Funding; InnoCare: Consultancy; MoreHealth: Consultancy; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding.

The correlation between blood lipids and clinicopathological features of breast cancer in young females.

Breast cancer is becoming more common in young adults. The relationships between blood lipids and breast cancer have been widely studied in recent years. In our current study, we investigated the potential correlations between blood lipids and clinicopathological features of breast cancer in young females. Fifty-nine young adults (40 years or younger) with pathologically confirmed invasive breast cancer that were treated in our center from October 2015 to March 2020 were enrolled in this study. These patients were divided into the negative group (n=40, with normal blood lipids) and positive group (n=19, with abnormal blood lipids) according to the preoperative blood lipid profiles, and differences in the clinicopathological features were compared between these two groups. Compared with the negative group, the positive group had a significantly higher rate of lymph node positivity (P=0.034); compared with the positive group, the negative group had a significantly higher rate of HER2 positivity (P=0.029). However, these two groups showed no significant difference in tumor size, molecular type, clinical stage, histological grade, tumor thrombus, and Ki-67 index (P values were 0.071, 0.227, 0.593, 0.396, 0.198, and 0.593, respectively). Blood lipid level has a certain correlation with lymph node metastasis and HER2 expression in young breast cancer patients. Therefore, blood lipid levels has a certain reference value in the clinical treatment of breast cancer.

Killing Action of Cuprous Oxide Nanoparticles on Breast Cancer Cells

Breast cancer (BC), a common malignancy, is intractable at present. Cuprous oxide nanoparticles (Conps) are new nanoparticles crucial in inhibiting tumor progression according to early studies, but their role in BC remains unclear. Field emission-scanning electron microscopy (FESEM) and field emission–transmission electron microscopy (FETEM) were used for the morphological observation of Conps, and energy-dispersive X-ray spectroscopy was used for their elemental composition analysis. Multipoint nitrogen adsorption was used to determine the Brunauer–Emmet–Teller of Conps, and their mean hydrodynamic size and zeta potential in water and intact cell medium were determined by dynamic light scattering (DLS). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Cell Counting Kit-8, Transwell assay, and flow cytometry were used to determine the effects of Conps on the biological function of BC cells. Western blotting was used to determine the changes in apoptosis-related proteins. Using FESEM and FETEM based on DLS and zeta potential determination, Conps was successfully constructed. Conps significantly lowered the viability of BC cells in a dose-dependent manner, significantly inhibited cell proliferation, invasion, and migration activities, and induced cell apoptosis. Western blotting demonstrated that Conps up-regulated Bax and caspase-3 proteins and down-regulated Bcl-2 protein. The results suggest that Conps can suppress the proliferation, invasion, and migration of BC cells and accelerate their apoptosis. This is a new potential strategy for the clinical treatment of BC.

USP44 hypermethylation promotes cell proliferation and metastasis in breast cancer.

Aim: The methylation and expression levels of USP44 in breast cancer were investigated and their effects on tumor cells were researched. Materials & methods: Bioinformatics was employed to identify the target gene from TCGA database. Sodium bisulfite and decitabine were used for DNA modification and demethylation, and methylation-specific PCR and reverse transcriptasePCR were performed to assess USP44 methylation and expression levels. Tumor cell behaviors were assayed via several in vitro experiments. Results: USP44 was hypermethylated, which caused its poor expression in breast cancer, whereasits overexpression significantly suppressed cancer cell proliferation, migration and invasion and induced apoptosis. Conclusion: USP44 negatively functions in cancer progression upon overexpression, indicating its potential as a therapeutic target for clinical treatment ofbreast cancer.

Abstract 5259: HSPA6 may be a new target by thyraquinone inhibiting migration and invasion of breast cancer cells

Abstract Background and Objective: Breast cancer is the malignant tumor with the highest incidence and the second highest mortality among women, and the incidence of breast cancer in China is increasing year by year. The treatment of breast cancer includes radiotherapy, chemotherapy, endocrine therapy, biological targeted therapy and traditional Chinese medicine adjuvant therapy; but the efficacy still needs to be further improved to benefit the patients. Thymoquinone (TQ) is a key component of black grass seed oil and has anti-cancer properties in a variety of tumors. Preliminary studies in our laboratory demonstrated that TQ has a significant inhibitory effect on the migration and invasion of triple negative breast cancer cells. Methods: To find the new target genes for the inhibition of migration and invasion of breast cancer cells by TQ, RNA-sequencing (RNA-seq) was conducted with and without TQ in human breast cancer cell line BT-549 with high invasion and migration characteristics. Quantitative and semi-quantitative RT-PCR was used to further verify the genes regulated by TQ, and then Western Blotting was used to compare the changes of the genes regulated by TQ at the protein level. Finally, the molecular mechanism of TQ inhibiting migration and invasion of human breast cancer cells was investigated by increasing or decreasing the expression of these genes. Results: Eighteen differentially expressed genes, which were closely related to the carcinomas in the experimental group and the control group, were obtained by RNA-seq. HSPA6 gene changed significantly, and showed an up-regulation after adding TQ, which was consistent with the results of RNA-seq. By RT-PCR and Western Blotting from different cell lines (BT549, MCF-7, ZR-75-30, SiHa, Caski), we found that the expression of HSPA6 in the experimental group was higher than that in the control group. The subsequent TQ treatment after knockdown / over-expression will be completed for HSPA6 protein functional effects by TQ. Conclusion: HSPA6 may be a new target gene for TQ to inhibit the migration and invasion of breast cancer cells. The success of this study will provide a new candidate target for clinical treatment of breast cancer. Funding support: National Natural Science Foundation of China (Grant No. 81672887, 81172049) Citation Format: Shiyi Shen, Ting Xiao, Ju Zhou, Chunli Wei, Junjiang Fu. HSPA6 may be a new target by thyraquinone inhibiting migration and invasion of breast cancer cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5259.

Electrochemical DNA Sensor for Sensitive BRCA1 Detection Based on DNA Tetrahedral-Structured Probe and Poly-Adenine Mediated Gold Nanoparticles.

BRCA1 is the biomarker for the early diagnosis of breast cancer. Detection of BRCA1 has great significance for the genetic analysis, early diagnosis and clinical treatment of breast cancer. In this work, we developed a simple electrochemical DNA sensor based on a DNA tetrahedral-structured probe (TSP) and poly-adenine (polyA) mediated gold nanoparticles (AuNPs) for the sensitive detection of BRCA1. A thiol-modified TSP was used as the scaffold on the surface of the screen-printed AuNPs electrode. The capture DNA (TSP) and reporter DNA were hybridized to the target DNA (BRCA1), respectively, to form the typical sandwich system. The nanocomposites of reporter DNA (polyA at the 5′ end) combined with AuNPs were employed for signal amplification which can capture multiple enzymes by the specificity between biotin and streptavidin. Measurements were completed in the electrochemical workstation by cyclic voltammetry and amperometry and we obtained the low limit of detection of 0.1 fM with the linear range from 1 fM to 1 nM. High sensitivity and good specificity of the proposed electrochemical DNA sensor showed potential applications in clinical early diagnosis for breast cancer.

A novel mitochondrial targeted hybrid peptide modified HPMA copolymers for breast cancer metastasis suppression

Primary tumor metastasis remains to be a tough obstacle for clinical breast cancer treatment. Since evidences have shown that mitochondria play a crucial role in tumor metastasis, we designed a mitochondrial targeted drug delivery system (P-D-R8MTS) based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers to simultaneously inhibit breast cancer progression and metastasis. A novel mitochondrial targeted hybrid peptide R8MTS, which consists of a cell penetrating peptide octaarginine (R8) and a mitochondrial targeting sequence ALD5MTS, was used as targeting ligand and attached to doxorubicin (DOX) as model drug (DOX-R8MTS). After entering into the tumor cells, DOX-R8MTS was pH-responsibly released from HPMA copolymer backbone in acidic lysosome and efficiently targeted to mitochondria, resulting in enhanced reactive oxygen species (ROS) generation and apoptosis initiation. By destroying mitochondria, P-D-R8MTS not only inhibited cell proliferation but also suppressed migration and invasion of breast cancer 4T1 and MDA-MB-231 cells in vitro. Moreover, P-D-R8MTS exhibited superior inhibition of tumor growth and showed no apparent lung metastatic nodules on 4T1-bearing mice in vivo, which was partially via down-regulation of typical proteins associated with tumor metastasis and invasion: matrix metalloproteinases-2 (MMP-2), vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β). Collectively, our work provided a prospectively potential strategy for metastatic cancer treatment through mitochondrial targeted drug delivery.

Possible involvement of TGF‑β‑SMAD‑mediated epithelial‑mesenchymal transition in pro‑metastatic property of PAX6.

Paired box 6 (PAX6) is a transcription factor that has oncogenic features. In breast cancer, PAX6 facilitates tumor progression; however, the underlying mechanism is largely unknown. The majority of breast cancer-related mortalities are associated with metastasis of cancer cells. Therefore, the present study aimed to investigate the role of PAX6 in breast tumor metastasis. PAX6 was stably overexpressed in breast cancer cells to perform tumor migration and metastasis assays in vitro and in vivo. In addition, the expression of PAX6 and transforming growth factor β (TGF-β)-SMAD signaling associated proteins on human breast cancer tissue array, as well as key factors involved in epithelial-mesenchymal transition (EMT) were assayed to explore the mechanism underlying metastasis of breast cancer cells. The expression levels of PAX6 were demonstrated to be increased in human breast cancer tissues and associated with poor clinical outcomes. Overexpression of PAX6 markedly promoted metastasis. Further investigation revealed that PAX6 overexpression increased TGF-β-SMAD signaling pathway and induced EMT. These results suggested that highly expressed PAX6 led to EMT through TGF-β-SMAD signaling pathway, thereby promoting cell metastasis and ultimately affecting survival in patients with breast cancer. Taken together, findings indicated that PAX6 may serve as a therapeutic target for the clinical treatment of breast cancer and the underlying mechanism could be used to overcome metastasis of cancer cells.

Revealing the selective mechanisms of inhibitors to PARP-1 and PARP-2 via multiple computational methods.

BackgroundResearch has shown that Poly-ADP-ribose polymerases 1 (PARP-1) is a potential therapeutic target in the clinical treatment of breast cancer. An increasing number of studies have focused on the development of highly selective inhibitors that target PARP-1 over PARP-2, its closest isoform, to mitigate potential side effects. However, due to the highly conserved and similar binding sites of PARP-1 and PARP-2, there is a huge challenge for the discovery and design of PARP-1 inhibitors. Recently, it was reported that a potent PARP-1 inhibitor named NMS-P118 exhibited greater selectivity to PARP-1 over PARP-2 compared with a previously reported drug (Niraparib). However, the mechanisms underlying the effect of this inhibitor remains unclear.MethodsIn the present study, classical molecular dynamics (MD) simulations and accelerated molecular dynamics (aMD) simulations combined with structural and energetic analysis were used to investigate the structural dynamics and selective mechanisms of PARP-1 and PARP-2 that are bound to NMS-P118 and Niraparib with distinct selectivity.ResultsThe results from classical MD simulations indicated that the selectivity of inhibitors may be controlled by electrostatic interactions, which were mainly due to the residues of Gln-322, Ser-328, Glu-335, and Tyr-455 in helix αF. The energetic differences were corroborated by the results from aMD simulations.ConclusionThis study provides new insights about how inhibitors specifically bind to PARP-1 over PARP-2, which may help facilitate the design of highly selective PARP-1 inhibitors in the future.

17‑AAG synergizes with Belinostat to exhibit a negative effect on the proliferation and invasion of MDA‑MB‑231 breast cancer cells.

Breast cancer is one of the most common malignancies that threaten the health of women. Although there are a few chemotherapies for the clinical treatment of breast cancer, these therapies are faced with the problems of drug-resistance and metastasis. Drug combination can help to reduce the adverse side effects of chemotherapies using single drugs, and also help to overcome common drug-resistance during clinical treatment of breast cancer. The present study reported the synergistic effect of the heat shock protein 90 inhibitor 17-AAG and the histone deacetylase 6 inhibitor Belinostat in triple-negative breast cancer (TNBC) MDA-MB-231 cells, by detection of proliferation, apoptosis and cell cycle arrest following treatment with this combination. Subsequently, RNA sequencing (RNA-seq) data was collected and analyzed to investigate the synergistic mechanism of this combination. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways revealed by RNA-seq data analysis, a wound-healing assay was used to investigate the effect of this combination on the migration of MDA-MB-231 cells. Compared with treatment with 17-AAG or Belinostat alone, both the viability inhibition and apoptosis rate of MDA-MB-231 cells were significantly enhanced in the combination group. The combination index values were <1 in three concentration groups. Revealed by the RNA-seq data analysis, the most significantly enriched KEGG pathways in the combination group were closely associated with cell migration. Based on these findings, the anti-migration effect of this combination was investigated. It was revealed that the migration of MDA-MB-231 cells was significantly suppressed in the combination group compared with in the groups treated with 17-AAG or Belinostat alone. In terms of specific genes, the mRNA expression levels of TEA domain family proteins were significantly decreased in the combination group, whereas the phosphorylation of YY1 associated protein 1 and modulator of VRAC current 1 was significantly enhanced in the combination group. These alterations may help to explain the anti-migration effect of this combination. Belinostat has already been approved as a treatment for T-cell lymphoma and 17-AAG is undergoing clinical trials. These findings could provide a beneficial reference for the clinical treatment of patients with TNBC.

Abstract P5-13-04: Gene expression profiling of breast cancers between high and low Ki-67 after short-term preoperative hormone therapy among hormone receptor-positive / human epidermal growth factor receptor 2-negative breast cancers with high Ki-67

Abstract Background In hormone receptor (HR)-positive / human epidermal growth factor receptor 2 (HER2)-negative breast cancers, high Ki-67 predicts poor prognosis. Recently, it has been reported that among breast cancers with high Ki-67, low Ki-67 after short-term preoperative hormone therapy (post Ki-67) might predict favorable prognosis compared to high post Ki-67 (SABCS 2017). However, the differences in gene expression profiling of breast cancers between high and low post Ki-67 among high Ki-67 before treatment are unclear. Therefore, this study aimed to clarify genetic differences in two groups and to explore novel therapeutic targets for the poor prognostic group after the treatment. Methods Seventy-seven patients with primary HR-positive / HER2-negative breast cancer who received an aromatase inhibitor for 2 weeks [NCBI Gene Expression Omnibus repository GSE80077:19 cases, GSE20181:58 cases] were enrolled in this study. Forty-five patients with high pre Ki-67 among them were stratified into two groups, high (H→H) and low (H→L) post Ki-67 after short-term preoperative hormone therapy. We compared gene expression profiling in two groups about the followings. 1) 3 genes (ESR1, PGR and ERBB2) related to classical clinical treatment strategy of breast cancer, immune- and inflammatory-related genes 2) 178 pathways (gene set analysis) 3) 41 genes that are targeted by FDA-approved drugs or have been investigated with clinical trials as molecular target agents for various malignant tumors including breast cancer Results 1) TNF that is inflammatory-related gene were significantly overexpressed in H→L group (P=0.021). However, 3 genes related to clinical treatment of breast cancer and immune-related genes expression had no significant difference between two groups. 2) 5 gene sets (Tryptophan metabolism, Propanoate metabolism, beta-Alanine metabolism, SNARE interactions in vesicular transport and Nucleotide excision repair) were significantly upregulated in H→L group. (P ≤ 0.005) 3) 5 targeted genes (PARP, BRCA2, FLT4, CDK6 and PDCD1LG2) were significantly overexpressed in H→H group (P ≤ 0.05). Conclusions There were different gene expression and biological processes in two groups stratified by post-Ki67. In the future, it is necessary to seek new therapeutic strategies for poor prognostic group with high post-Ki67 in considerations of these differences. Citation Format: Yukiko Kajiwara, Takayuki Iwamoto, Yusuke Otani, Miwa Fujihara, Yoko Suzuki, Minami Hatono, Takahiro Tsukioki, Kengo Kawada, Mariko Kochi, Hirokuni Ikeda, Tadahiko Shien, Naruto Taira, Hiroyoshi Doihara. Gene expression profiling of breast cancers between high and low Ki-67 after short-term preoperative hormone therapy among hormone receptor-positive / human epidermal growth factor receptor 2-negative breast cancers with high Ki-67 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-13-04.

Resibufogenin suppresses tumor growth and Warburg effect through regulating miR-143-3p/HK2 axis in breast cancer.

Increasing evidence confirmed that the Warburg effect plays an important role involved in the progression of malignant tumors. Resibufogenin (RES) has been proved to have a therapeutic effect in multiple malignant tumors. However, the mechanism of whether RES exerted an antitumor effect on breast cancer through regulating the Warburg effect is largely unknown. The effect of RES on glycolysis was determined by glucose consumption, lactate production, ATP generation, extracellular acidification rate and oxygen consumption rate in breast cancer cells. The total RNA and protein levels were respectively measured by RT-qPCR and western blot. Cell proliferation and apoptosis were examined using the CCK-8 assay, colony formation assay, and flow cytometry, respectively. The interaction between miR-143-3p and HK2 was verified by dual-luciferase reporter gene assay. We also evaluated the influence of RES on the tumor growth and Warburg effect in vivo. RES treatment significantly decreased glycolysis, cell proliferation and induced apoptosis of both MDA-MB-453 and MCF-7 cells. Simultaneously, the expression of HK2 was decreased in breast cancer cells treated with RES, which was positively associated with tumor size and glycolysis. Moreover, HK2 was a direct target gene of miR-143-3p. Mechanistically, upregulation of miR-143-3p by RES treatment inhibited tumor growth by downregulating HK2-mediated Warburg effect in breast cancer. Our findings suggested that RES exerted anti-tumorigenesis and anti-glycolysis activities in breast cancer through upregulating the inhibitory effect of miR-143-3p on HK2 expression, which provided a new potential strategy for breast cancer clinical treatment.