Metastatic breast cancer: the treatment challenge

Integration of an LPAR1 Antagonist into Liposomes Enhances Their Internalization and Tumor Accumulation in an Animal Model of Human Metastatic Breast Cancer

Lysophosphatidic acid receptor 1 (LPAR1) is elevated in breast cancer. The deregulation of LPAR1, including the function and level of expression, is linked to cancer initiation, progression, and metastasis. LPAR1 antagonists, AM095 or Ki16425, may be effective therapeutic molecules, yet their limited water solubility hinders in vivo delivery. In this study, we report on the synthesis of two liposomal formulations incorporating AM095 or Ki16425, embedded within the lipid bilayer, as targeted nanocarriers for metastatic breast cancer (MBC). The data show that the Ki16425 liposomal formulation exhibited a 50% increase in internalization by MBC mouse epithelial cells (4T1) and a 100% increase in tumor accumulation in a mouse model of MBC compared with that of a blank liposomal formulation (control). At the same time, normal mouse epithelial cells (EpH-4Ev) internalized the Ki16425 liposomal formulation 25% lesser than the control formulation. Molecular dynamics simulations show that the integration of AM095 or Ki16425 modified the physical and mechanical properties of the lipid bilayer, making it more flexible in these liposomal formulations compared with liposomes without drug. The incorporation of an LPAR1 antagonist within a liposomal drug delivery system represents a viable therapeutic approach for targeting the LPA-LPAR1 axis, which may hinder the progression of MBC.

In Silico Mixed Ligand/Structure-Based Design of New CDK-1/PARP-1 Dual Inhibitors as Anti-Breast Cancer Agents

CDK-1 and PARP-1 play crucial roles in breast cancer progression. Compounds acting as CDK-1 and/or PARP-1 inhibitors can induct cell death in breast cancer with a selective synthetic lethality mechanism. A mixed treatment by means of CDK-1 and PARP-1 inhibitors resulted in radical breast cancer cell growth reduction. Inhibitors with a dual target mechanism of action could arrest cancer progression by simultaneously blocking the DNA repair mechanism and cell cycle, resulting in advantageous monotherapy. To this aim, in the present work, we identified compound 645656 with a significant affinity for both CDK-1 and PARP-1 by a mixed ligand- and structure-based virtual screening protocol. The Biotarget Predictor Tool was used at first in a Multitarget mode to filter the large National Cancer Institute (NCI) database. Then, hierarchical docking studies were performed to further screen the compounds and evaluate the ligands binding mode, whose putative dual-target mechanism of action was investigated through the correlation between the antiproliferative activity data and the target proteins' (CDK-1 and PARP-1) expression pattern. Finally, a Molecular Dynamics Simulation confirmed the high stability of the most effective selected compound 645656 in complex with both PARP-1 and CDK-1.

FTO-mediated epigenetic upregulation of LINC01559 confers cell resistance to docetaxel in breast carcinoma by suppressing miR-1343-3p

This study was to explore the regulatory effect of long non-coding RNA LINC01559 on Docetaxel resistance in breast carcinoma (BCa) and its underlying mechanism. In the present study, we found that LINC01559 expression was elevated and LINC01559 overexpression facilitated docetaxel resistance in BCa cells. Moreover, it was revealed that the upregulation of LINC01559 in BCa cells was induced by FTO-mediated demethylation in an m6A-YTHDF2-dependent manner. Additionally, Dual-luciferase reporter assay confirmed the binding ability between LINC01559 and miR-1343-3p, and Pearson correlation analysis showed a negative correlation between them. Particularly, miR-1343-3p inhibition partly abolished the suppression on docetaxel resistance in BCa cells caused by LINC01559 knockdown. To sum up, FTO-mediated epigenetic upregulation of LINC01559 promoted cell resistance to Docetaxel in BCa by negatively regulating miR-1343-3p.

Role of glycosylation in breast cancer progression and metastasis: implications for miRNA, EMT and multidrug resistance

Breast cancer (BC) is one of the leading causes of death in women, globally. A variety of biological processes results in metastasis, a poorly understood pathological phenomenon, causing a high relapse rate. Glycosylation, microribonucleic acids (miRNAs) and epithelial to mesenchymal transition (EMT), have been shown to regulate this cascade where tumor cells detach from their primary site, enter the circulatory system and colonize distant sites. Integrated proteomics and glycomics approaches have been developed to probe the molecular mechanism regulating such metastasis. In this review, we describe specific aspects of glycosylation and its interrelation with miRNAs, EMT and multidrug resistance during BC progression and metastasis. We explore various approaches that determine the role of proteomes and glycosylation in BC diagnosis, therapy and drug discovery.

Is Palbociclib a cost-effective strategy in the second-line treatment of metastatic breast cancer in Iran?

BACKGROUND & AIMS

This study evaluates the cost-effectiveness of Palbociclib in the second-line treatment of hormone receptor-positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) in Iran.

METHODS

The present economic evaluation used a partitioned survival model (PSM). This model compares lifetime costs and disease outcomes among groups receiving different medication combinations containing Palbociclib, Fulvestrant, Everolimus, Ribociclib, and Abemaciclib as the second-line therapy for HR+/HER2- MBC. The model was conducted from Iran's healthcare perspective, structured with 1-month cycles, and the evaluation time horizon in the base analysis was set to 180 cycles (15 years). Transition probabilities were extracted using the survival curves. The cost information was extracted based on the year 2020. The Quality Adjusted Life Years (QALY) was considered the final outcome unit, and the cost-effectiveness of different combinations is calculated as cost per QALY. The annual discount rate of 5% was considered for costs and QALYs. Two times Iran's GDP per capita (800,000,000 IRR = US$5934) was used as the threshold. Finally, due to the uncertainty of some parameters, deterministic and probabilistic sensitivity analyses were carried out.

RESULTS

The base case results showed that the highest cost was for the 'Ribociclib+ Fulvestrant' combination (US$89,629.56), and the lowest price was for the 'Iranian Everolimus + Fulvestrant' combination (US$10,740.09). 'Palbociclib + Fulvestrant' brings about the highest value of 1.456 incremental QALYs compared to other strategies. Finally, the 'Iranian Palbociclib + Fulvestrant' was the cost-effective combination, with an incremental cost-effectiveness ratio (ICER) of US$4,201 compared to other strategies. The base case results were supported by the probabilistic sensitivity analysis. Deterministic sensitivity analysis showed that the cost of Iranian Palbociclib has a threshold of US$582.99.

CONCLUSIONS

The 'Iranian Palbociclib + Fulvestrant' combination was cost-effective in second-line therapy for HR+ HER2- MBC in Iran.

Oncolytic virotherapy for metastatic breast cancer - a case report

Background

Breast cancer is one of the most common malignancies worldwide and remains incurable after metastasis, with a 3-year overall survival rate of <40%.

Case presentation

A 40-year-old, Caucasian patient with a grade-3 estrogen receptor-, progesterone receptor-, Her2-positive breast tumor and two lung nodules was treated with intramuscular targeted immunotherapy with trastuzumab and oral tamoxifen hormone therapy, together with customized intra-tumoral oncolytic virotherapy (IT-OV) over a 17-month period. PET/CT imaging at 3 and 6 months showed increased primary tumor size and metabolic glucose uptake in the primary tumor, axillary lymph nodes and lung nodules, which were paralleled by a hyperimmune reaction in the bones, liver, and spleen. Thereafter, there was a steady decline in both tumor size and metabolic activity until no radiographic evidence of disease was observed. The treatment regimen was well tolerated and good quality of life was maintained throughout.

Conclusion

Integration of IT-OV immunotherapy in standard treatment protocols presents an attractive modality for late-stage primary tumors with an abscopal effect on metastases.

Immune cells in residual disease and recurrence

Tumor recurrence following potentially curative therapy constitutes a major obstacle to achieving cures in patients with cancer. Recurrent tumors frequently arise from a population of residual cancer cells - also referred to as minimal residual disease (RD) or persister cells - that survive therapy and persist for prolonged periods prior to tumor relapse. While there has been significant recent progress in deciphering tumor-cell-intrinsic pathways that regulate residual cancer cell survival and recurrence, much less is known about how the tumor microenvironment (TME) of residual tumors impacts persister cancer cells or tumor recurrence. In this review, we highlight recent studies exploring the regulation and function of immune cells in RD and discuss therapeutic opportunities to target immune cells in residual tumors.

Construction of Human Immune and Naive scFv Phage Display Libraries

Antibody phage display is a widely used in vitro selection technology for the generation of human recombinant antibodies and has yielded thousands of useful antibodies for research, diagnostics, and therapy. In order to successfully generate antibodies using phage display, the basis is the construction of high-quality antibody gene libraries. Here, we describe detailed methods for the construction of such high-quality immune and naive scFv gene libraries of human origin. These protocols were used to develop human naive (e.g., HAL9/10) and immune libraries, which resulted in thousands of specific antibodies for all kinds of applications.

Patient-centered dosing: oncologists' perspectives about treatment-related side effects and individualized dosing for patients with metastatic breast cancer (MBC)

PURPOSE

Although metastatic breast cancer (MBC) is treatable, it is not curable and most patients remain on treatment indefinitely. While oncologists commonly prescribe the recommended starting dose (RSD) from the FDA-approved label, patient tolerance may differ from that seen in clinical trials. We report on a survey of medical oncologists' perspectives about treatment-related toxicity and willingness to discuss flexible dosing with patients.

METHODS

We disseminated a confidential survey via social media/email in Spring 2021. Eligible respondents needed to be US-based medical oncologists with experience treating patients with MBC.

RESULTS

Of 131 responses, 119 were eligible. Physicians estimated that 47% of their patients reported distressing treatment-related side effects; of these, 15% visited the Emergency Room/hospital and 37% missed treatment. 74% (n = 87) of doctors reported improvement of patient symptoms after dose reduction. 87% (n = 104) indicated that they had ever, if appropriate, initiated treatment at lower doses. Most (85%, n = 101) respondents did not believe that the RSD is always more effective than a lower dose and 97% (n = 115) were willing to discuss individualized dosing with patients.

CONCLUSION

Treatment-related side effects are prevalent among patients with MBC, resulting in missed treatments and acute care visits. To help patients tolerate treatment, oncologists may decrease initial and/or subsequent doses. The majority of oncologists reject the premise that a higher dose is always superior and are willing to discuss individualized dosing with patients. Given potential improvements regarding quality of life and clinical care, dose modifications should be part of routine shared decision-making between patients and oncologists.

Overexpression of SCYL1 Is Associated with Progression of Breast Cancer

SCYL1 is a pseudokinase and plays roles in cell division and gene transcription, nuclear/cytoplasmic shuttling of tRNA, protein glycosylation, and Golgi morphology. However, the role of SCYL1 in human breast cancer progression remains largely unknown. In this study, we determined expression of SCYL1 in breast cancer by searching the Cancer Genome Atlas (TCGA) and Tumor Immunoassay Resource (TIMER) databases. Meanwhile, we collected breast tumor tissue samples from 247 cases and detected expression of SCYL1 in the tumors using the tissue microarray assay (TMA). Association of SCYL1 with prognosis of breast cancer was determined based on the PrognoScan database. The results have shown that SCYL1 is overexpressed in breast cancer, and the expression of SCYL1 is associated with poor clinical outcomes of breast cancer patients. Furthermore, knockdown of SCYL1 by shRNAs significantly inhibited the proliferation and migration of breast cancer cells. Taken together, our data suggest that SCYL1 is a biomarker for poor prognosis of breast cancer, has a promoting role in breast cancer progression, and is a potential target for breast cancer therapy.

PRR16/Largen Induces Epithelial-Mesenchymal Transition through the Interaction with ABI2 Leading to the Activation of ABL1 Kinase

Advanced or metastatic breast cancer affects multiple organs and is a leading cause of cancer-related death. Cancer metastasis is associated with epithelial-mesenchymal metastasis (EMT). However, the specific signals that induce and regulate EMT in carcinoma cells remain unclear. PRR16/Largen is a cell size regulator that is independent of mTOR and Hippo signalling pathways. However, little is known about the role PRR16 plays in the EMT process. We found that the expression of PRR16 was increased in mesenchymal breast cancer cell lines. PRR16 overexpression induced EMT in MCF7 breast cancer cells and enhances migration and invasion. To determine how PRR16 induces EMT, the binding proteins for PRR16 were screened, revealing that PRR16 binds to Abl interactor 2 (ABI2). We then investigated whether ABI2 is involved in EMT. Gene silencing of ABI2 induces EMT, leading to enhanced migration and invasion. ABI2 is a gene that codes for a protein that interacts with ABL proto-oncogene 1 (ABL1) kinase. Therefore, we investigated whether the change in ABI2 expression affected the activation of ABL1 kinase. The knockdown of ABI2 and PRR16 overexpression increased the phosphorylation of Y412 in ABL1 kinase. Our results suggest that PRR16 may be involved in EMT by binding to ABI2 and interfering with its inhibition of ABL1 kinase. This indicates that ABL1 kinase inhibitors may be potential therapeutic agents for the treatment of PRR16-related breast cancer.

Developing an Academic and Community Practice Collaborative Care Model for Metastatic Breast Cancer Care: A Protocol using the Dynamic Adaptation Process (Preprint)

Background

Metastatic breast cancer (MBC) remains incurable despite significant treatment advances. Coordinating care for patients with MBC can be challenging given the various treatment options, available clinical trials, and frequent need for ancillary services. To optimize MBC care, we designed a project for adapting and developing an academic and community practice collaborative care model for MBC care (Project ADAPT), based on the Ending Metastatic Breast Cancer for Everyone (EMBRACE) program developed at Dana Farber Cancer Institute.

Objective

We aim to describe the implementation science–based study design and innovative components of Project ADAPT.

Methods

Project ADAPT uses the Dynamic Adaptation Process informed by the Exploration, Preparation, Implementation, Sustainment framework. Washington University School of Medicine (WUSM) partnered with 3 community hospitals in the St. Louis region covering rural and urban settings. The exploration and preparation phases provide patient and provider feedback on current referral practices to finalize the approach for the implementation phase. At the implementation phase, we will enroll patients with MBC at these 3 community sites to evaluate potential collaborative care at WUSM and assess the impact of this collaborative care model on referral satisfaction and acceptability for patients with MBC and their providers. Patients may then return to their community site for care or continue to receive part of their care at WUSM. We are incorporating virtual and digital health strategies to improve MBC care coordination in order to minimize patient burden.

Results

The exploration phase is ongoing. As of August 2021, we have recruited 21 patient and provider participants to complete surveys of the current collaborative care process at WUSM. Using a 2-tailed paired t test, 44 patients (including 10 patients from the exploration phase) and 32 oncologists are required to detect an effect size of 0.5 with 80% power at a level of significance of .05. Throughout this phase and in preparation for the implementation phase, we have iteratively updated and refined our surveys for the implementation phase based on testing of our data collection instruments. Our partner sites are in various stages of the single institutional review board (IRB) approval process. We have ongoing engagement with all partner sites, which has helped solidify our participant recruitment strategies and design patient-friendly recruitment materials. In addition, we have included a patient advocate on the research team. Members of the research team have launched a single IRB Support Network at WUSM to create a repository of the single IRB procedures in order to streamline the partner site onboarding process and facilitate enhanced collaboration across institutions.

Conclusions

With this robust model, we expect that patients with MBC will receive optimal care regardless of geographical location and the model will improve patient and provider experiences when navigating the health system.

International Registered Report Identifier (IRRID)

DERR1-10.2196/35736

The Secretome of Human Neonatal Mesenchymal Stem Cells Modulates Doxorubicin-Induced Cytotoxicity: Impact in Non-Tumor Cells

Doxorubicin (Dox) is one of the most widely used treatments for breast cancer, although limited by the well-documented cardiotoxicity and other off-target effects. Mesenchymal stem cell (MSC) secretome has shown immunomodulatory and regenerative properties, further potentiated under 3D conditions. This work aimed to uncover the effect of the MSC-derived secretome from 3D (CM3D) or 2D (CM2D) cultures, in human malignant breast cells (MDA-MB-231), non-tumor breast epithelial cells (MCF10A) and differentiated AC16 cardiomyocytes, co-treated with Dox. A comprehensive proteomic analysis of CM3D/CM2D was also performed to unravel the underlying mechanism. CM3D/CM2D co-incubation with Dox revealed no significant differences in MDA-MB-231 viability when compared to Dox alone, whereas MCF10A and AC16 viability was consistently improved in Dox+CM3D-treated cells. Moreover, neither CM2D nor CM3D affected Dox anti-migratory and anti-invasive effects in MDA-MB-231. Notably, Ge-LC-MS/MS proteomic analysis revealed that CM3D displayed protective features that might be linked to the regulation of cell proliferation (CAPN1, CST1, LAMC2, RANBP3), migration (CCN3, MMP8, PDCD5), invasion (TIMP1/2), oxidative stress (COX6B1, AIFM1, CD9, GSR) and inflammation (CCN3, ANXA5, CDH13, GDF15). Overall, CM3D decreased Dox-induced cytotoxicity in non-tumor cells, without compromising Dox chemotherapeutic profile in malignant cells, suggesting its potential use as a chemotherapy adjuvant to reduce off-target side effects.

The molecular mechanisms and therapeutic potential of EZH2 in breast cancer

Due to its high occurrence and mortality rate, breast cancer has been studied from various aspects as one of the cancer field's hot topics in the last decade. Epigenetic alterations are spoused to be highly effective in breast cancer development. Enhancer of zeste homolog 2 (EZH2) is an enzymatic epi-protein that takes part in most vital cell functions by its different action modes. EZH2 is suggested to be dysregulated in specific breast cancer types, particularly in advanced stages. Mounting evidence revealed that EZH2 overexpression or dysfunction affects the pathophysiology of breast cancer. In this review, we discuss biological aspects of the EZH2 molecule with a focus on its newly identified action mechanisms. We also highlight how EZH2 plays an essential role in breast cancer initiation, progression, metastasis, and invasion, which emerged as a worthy target for treating breast cancer in different approaches.

Iron oxide nanoparticle targeted chemo-immunotherapy for triple negative breast cancer

Triple negative breast cancer is difficult to treat effectively, due to its aggressiveness, drug resistance, and lack of the receptors required for hormonal therapy, particularly at the metastatic stage. Here, we report the development and evaluation of a multifunctional nanoparticle formulation containing an iron oxide core that can deliver doxorubicin, a cytotoxic agent, and polyinosinic:polycytidylic acid (Poly IC), a TLR3 agonist, in a targeted and simultaneous fashion to both breast cancer and dendritic cells. Endoglin-binding peptide (EBP) is used to target both TNBC cells and vasculature epithelia. The nanoparticle demonstrates favorable physicochemical properties and a tumor-specific targeting profile. The nanoparticle induces tumor apoptosis through multiple mechanisms including direct tumor cell killing, dendritic cell-initiated innate and T cell-mediated adaptive immune responses. The nanoparticle markedly inhibits tumor growth and metastasis and substantially extends survival in an aggressive and drug-resistant metastatic mouse model of triple negative breast cancer (TNBC). This study points to a promising platform that may substantially improve the therapeutic efficacy for treating metastatic TNBC.

Depressive Symptoms and Quality of Life Associated With the Use of Monoclonal Antibodies in Breast Cancer Treatment

OBJECTIVES

To assess the relationship between (a) chemotherapy and monoclonal antibody (mAb) treatments and (b) depressive symptoms and quality of life (QOL) in patients with breast cancer.

SAMPLE & SETTING

182 women with breast cancer in Spain who were undergoing chemotherapy with or without mAbs.

METHODS & VARIABLES

An observational, cross-sectional study was carried out. The European Organisation for Research and Treatment of Cancer (EORTC) QOL Questionnaire-Core 30 and the EORTC QOL Questionnaire-Breast Cancer were used to assess QOL. Patients were screened for depressive symptoms using the Beck Depression Inventory-II.

RESULTS

No relationship was found between the use of mAbs with chemotherapy and QOL, except for incidence of diarrhea. However, depressive symptoms had a negative and highly significant influence on the majority of the QOL parameters.

IMPLICATIONS FOR NURSING

The presence of depressive symptoms negatively affects QOL. Used concurrently, mAbs and chemotherapy do not negatively influence QOL, but some adverse effects, such as diarrhea, are common.

Exosomal miRNA-205 promotes breast cancer chemoresistance and tumorigenesis through E2F1

Breast cancer (BC) is a common malignant tumor in females. The challenge in treating BC is overcoming chemoresistance. Exosome-mediated transfer of miRNAs is a molecule-shuttle in intercellular communication. Thus, we aimed to investigate whether exosomal miRNA-205 could affect chemoresistance and tumorigenesis in recipient tumor cells and to elucidate the underlying mechanism in vivo and in vitro. Microarray and qRT-PCR assays demonstrated that miRNA-205 was upregulated in tamoxifen resistance MCF-7/TAMR-1 (M/T) cells and M/T cell-derived exosomes (M/T-Exo). The M/T-Exo was internalized by human BC cells (BCCs), causing increased expression of miRNA-205 in BCCs. Coculturing with M/T-Exo promoted tamoxifen resistance, proliferation, migration, and invasion while suppressed apoptosis in recipient BCCs, which were associated with activating the caspase pathway and phosphorylating Akt. Luciferase reporter assays showed that miRNA-205 directly targeted E2F Transcription Factor 1 (E2F1) in BCCs. Furthermore, knockdown of miRNA-205 or overexpression of E2F1 reversed the roles of M/T-Exo in BCCs. In vivo experiments showed that the intratumoral injection of M/T-Exo caused greater tamoxifen resistance and larger tumor size relative to mice treated with miRNA-205-knockdown or E2F1-overexpressing BCCs. Together, the results suggest that exosomal miRNA-205 may promote tamoxifen resistance and tumorigenesis in BC through targeting E2F1 in vivo and in vitro.

Knockdown of circ_0006528 Suppresses Cell Proliferation, Migration, Invasion, and Adriamycin Chemoresistance via Regulating the miR-1236-3p/CHD4 Axis in Breast Cancer

BACKGROUND

Adriamycin (ADM) is one of the postoperative chemotherapy drugs for breast cancer (BCa) patients. Circular RNAs have been shown to modulate ADM resistance in many cancers. However, it is unclear whether circ_0006528 can modulate the ADM chemoresistance in BCa.

METHODS

Levels of circ_0006528, microRNA-1236-3p (miR-1236-3p), and chromodomain helicase DNA-binding protein 4 (CHD4) were detected by quantitative real-time polymerase chain reaction or western blot. Cell proliferation, the half maximal inhibitory concentration (IC50) value of ADM, and cell migration and invasion were evaluated by cell counting kit-8 and transwell assays, respectively. The interaction among circ_0006528, miR-1236-3p, and CHD4 was confirmed using dual-luciferase reporter assays. Tumor formation in nude mice was performed to explore the effect of circ_0006528 in vivo.

RESULTS

Higher levels of circ_0006528 and CHD4 and lower level of miR-1236-3p were found in ADM-resistant BCa tissues and cells, and patients with high circ_0006528 had a shorter overall survival. Circ_0006528 could directly bind to miR-1236-3p, and circ_0006528 knockdown or miR-1236-3p overexpression could suppress cell proliferation, migration, invasion, and ADM resistance in ADM-resistant BCa cells. Moreover, circ_0006528-regulated CHD4 expression by sponging miR-1236-3p, and CHD4 elevation reversed the inhibitory effect of circ_0006528 knockdown on ADM-resistant BCa cells. Consistently, circ_0006528 inhibition retarded ADM-resistant BCa tumor growth in vivo by decreasing CHD4 and increasing miR-1236-3p.

CONCLUSIONS

Downregulation of circ_0006528 restrained cell proliferation, migration, invasion, and drug resistance of ADM-resistant BCa cells through inhibiting CHD4 and inducing miR-1236-3p.

c-Myb interferes with inflammatory IL1α-NF-κB pathway in breast cancer cells

The transcription factor c-Myb can be involved in the activation of many genes with protumorigenic function; however, its role in breast cancer (BC) development is still under discussion. c-Myb is considered as a tumor-promoting factor in the early phases of BC, on the other hand, its expression in BC patients relates to a good prognosis. Previously, we have shown that c-Myb controls the capacity of BC cells to form spontaneous lung metastasis. Reduced seeding of BC cells to the lungs is linked to high expression of c-Myb and a decline in expression of a specific set of inflammatory genes. Here, we unraveled a c-Myb-IL1α-NF-κB signaling axis that takes place in tumor cells. We report that an overexpression of c-Myb interfered with the activity of NF-κB in several BC cell lines. We identified IL1α to be essential for this interference since it was abrogated in the IL1α-deficient cells. Overexpression of IL1α, as well as addition of recombinant IL1α protein, activated NF-κB signaling and restored expression of the inflammatory signature genes suppressed by c-Myb. The endogenous levels of c-Myb negatively correlated with IL1α on both transcriptional and protein levels across BC cell lines. We concluded that inhibition of IL1α expression by c-Myb reduces NF-κB activity and disconnects the inflammatory circuit, a potentially targetable mechanism to mimic the antimetastatic effect of c-Myb with therapeutic perspective.

Regulatory T lymphocyte infiltration in metastatic breast cancer-an independent prognostic factor that changes with tumor progression

Background

Patients diagnosed with metastatic breast cancer have poor outcome with a median survival of approximately 2 years. While novel therapeutic options are urgently needed, the great majority of breast cancer research has focused on the primary tumor and less is known about metastatic breast cancer and the prognostic impact of the metastatic tumor microenvironment. Here we investigate the immune landscape in unique clinical material. We explore how the immune landscape changes with metastatic progression and elucidate the prognostic role of immune cells infiltrating primary tumors and corresponding lymph node and more importantly distant metastases.

Methods

Immunohistochemical staining was performed on human breast cancer tissue microarrays from primary tumors (n = 231), lymph node metastases (n = 129), and distant metastases (n = 43). Infiltration levels of T lymphocytes (CD3⁺), regulatory T lymphocytes (Tregs, FOXP3⁺), macrophages (CD68⁺), and neutrophils (NE⁺) were assessed in primary tumors. T lymphocytes and Tregs were further investigated in lymph node and distant metastases.

Results

T lymphocyte and Treg infiltration were the most clinically important immune cell populations in primary tumors. Infiltration of T lymphocytes and Tregs in primary tumors correlated with proliferation (P = 0.007, P = 0.000) and estrogen receptor negativity (P = 0.046, P = 0.026). While both T lymphocyte and Treg infiltration had a negative correlation to luminal A subtype (P = 0.031, P = 0.000), only Treg infiltration correlated to luminal B (P = 0.034) and triple-negative subtype (P = 0.019). In primary tumors, infiltration of T lymphocytes was an independent prognostic factor for recurrence-free survival (HR = 1.77, CI = 1.01–3.13, P = 0.048), while Treg infiltration was an independent prognostic factor for breast cancer-specific survival (HR = 1.72, CI = 1.14–2.59, P = 0.01). Moreover, breast cancer patients with Treg infiltration in their distant metastases had poor post-recurrence survival (P = 0.039). Treg infiltration levels changed with metastatic tumor progression in 50% of the patients, but there was no significant trend toward neither lower nor higher infiltration.

Conclusion

Treg infiltration could have clinical applicability as a prognostic biomarker, deciphering metastatic breast cancer patients with worse prognosis, and accordingly, could be a suitable immunotherapeutic target for patients with metastatic breast cancer. Importantly, half of the patients had changes in Treg infiltration during the course of metastatic progression emphasizing the need to characterize the metastatic immune landscape.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01403-0.

miR-325-3p Promotes the Proliferation, Invasion, and EMT of Breast Cancer Cells by Directly Targeting S100A2

This study was designed to investigate the precise mechanisms of miR-325-3p/S100A2 axis in breast cancer (BC). In this study, we found that the level of miR-325-3p was dramatically increased in BC tissues and cell lines, and the expression of S100A2 was significantly decreased. Also, the high level of miR-325-3p was closely associated with low expression of S100A2 in BC tissues. Moreover, introduction of miR-325-3p significantly promoted proliferation, invasion, and EMT of BC cells. Bioinformatics analysis predicted that the S100A2 was a potential target gene of miR-325-3p. Luciferase reporter assay demonstrated that miR-325-3p could directly target S100A2. In addition, miR-325-3p overexpression had similar effects with knockdown of S100A2 on BC cells. Overexpression of S100A2 in BC cells partially reversed the promoted effects of miR-325-3p mimic. Overexpression of miR-325-3p promoted cell proliferation, invasion, and EMT of BC cells by directly downregulating S100A2 expression.

Triplet Therapy with Palbociclib, Taselisib, and Fulvestrant in PIK3CA-Mutant Breast Cancer and Doublet Palbociclib and Taselisib in Pathway-Mutant Solid Cancers

Cyclin-dependent kinase 4/6 (CDK4/6) and PI3K inhibitors synergize in PIK3CA-mutant ER-positive HER2-negative breast cancer models. We conducted a phase Ib trial investigating the safety and efficacy of doublet CDK4/6 inhibitor palbociclib plus selective PI3K inhibitor taselisib in advanced solid tumors, and triplet palbociclib plus taselisib plus fulvestrant in 25 patients with PIK3CA-mutant, ER-positive HER2-negative advanced breast cancer. The triplet therapy response rate in PIK3CA-mutant, ER-positive HER2-negative cancer was 37.5% [95% confidence interval (CI), 18.8-59.4]. Durable disease control was observed in PIK3CA-mutant ER-negative breast cancer and other solid tumors with doublet therapy. Both combinations were well tolerated at pharmacodynamically active doses. In the triplet group, high baseline cyclin E1 expression associated with shorter progression-free survival (PFS; HR = 4.2; 95% CI, 1.3-13.1; P = 0.02). Early circulating tumor DNA (ctDNA) dynamics demonstrated high on-treatment ctDNA association with shorter PFS (HR = 5.2; 95% CI, 1.4-19.4; P = 0.04). Longitudinal plasma ctDNA sequencing provided genomic evolution evidence during triplet therapy. SIGNIFICANCE: The triplet of palbociclib, taselisib, and fulvestrant has promising efficacy in patients with heavily pretreated PIK3CA-mutant ER-positive HER2-negative advanced breast cancer. A subset of patients with PIK3CA-mutant triple-negative breast cancer derived clinical benefit from palbociclib and taselisib doublet, suggesting a potential nonchemotherapy targeted approach for this population.This article is highlighted in the In This Issue feature, p. 1.

Viroimmunotherapy for breast cancer: promises, problems and future directions

Virotherapy, a strategy to use live viruses as therapeutics, is a relatively novel field in the treatment of cancer. With the advancements in molecular biology and virology, there has been a huge increase in research on cancer virotherapy. For the treatment of cancer, viruses could be used either as vectors in gene therapy or as oncolytic agents. A variety of viruses have been studied for their potential usage in gene therapy or oncolytic therapy. In this review, we discuss virotherapy with a special focus on breast cancer. Breast cancer is the most common cancer and the leading cause of cancer-related deaths in women worldwide. Current treatments are insufficient to cure metastatic breast cancer and are often associated with severe side effects that further deteriorates patients' quality of life. Therefore, novel therapeutic approaches such as virotherapy need to be developed for the treatment of breast cancer. Here we summarize the current treatments for breast cancer and the potential use of virotherapy in the treatment of the disease. Furthermore, we discuss the use of oncolytic viruses as immunotherapeutics and the rational combination of oncolytic viruses with other therapeutics for optimal treatment of breast cancer. Finally, we outline the progress made in virotherapy for breast cancer and the shortcomings that need to be addressed for this novel therapy to move to the clinic for better treatment of breast cancer.

Adaptation and selection shape clonal evolution of tumors during residual disease and recurrence

The survival and recurrence of residual tumor cells following therapy constitutes one of the biggest obstacles to obtaining cures in breast cancer, but it remains unclear how the clonal composition of tumors changes during relapse. We use cellular barcoding to monitor clonal dynamics during tumor recurrence in vivo. We find that clonal diversity decreases during tumor regression, residual disease, and recurrence. The recurrence of dormant residual cells follows several distinct routes. Approximately half of the recurrent tumors exhibit clonal dominance with a small number of subclones comprising the vast majority of the tumor; these clonal recurrences are frequently dependent upon Met gene amplification. A second group of recurrent tumors comprises thousands of subclones, has a clonal architecture similar to primary tumors, and is dependent upon the Jak/Stat pathway. Thus the regrowth of dormant tumors proceeds via multiple routes, producing recurrent tumors with distinct clonal composition, genetic alterations, and drug sensitivities.

The cellular composition of recurrent tumors can provide insight into resistance to therapy and inform on second line therapies. Here, using a genetically modified mouse, the authors perform barcoding experiments of the primary tumors to allow them to study the clonal dynamics of tumor recurrence.

Circular RNA Circ_0000442 acts as a sponge of MiR-148b-3p to suppress breast cancer via PTEN/PI3K/Akt signaling pathway

Breast cancer remains the most common malignancy in women worldwide. Circular RNAs (circRNAs) are a newly validated type of endogenous non-coding RNAs and accumulating evidence suggests that aberrant circRNAs are involved in disease pathogenesis. However, the function of circRNAs in breast cancer remains largely unknown. This study is aimed to characterize the potential role and mechanism of hsa_circ_0000442 (circ_0000442) in breast cancer. The human breast epithelial cell line (MCF-10A), breast cancer cell lines (MCF-7, T47D, BT474, SK-BR-3, MDA-MB-231, SUM-1315) and the Balb/C Nude mice were used for exploration, and the qRT-PCR, western blot, dual-luciferase reporter assay, glo assay, colony formation assay, and tumor xenograft were carried out for investigation. In this study, the results showed a lower expression of circ_0000442 in breast cancer tumor tissues compared with the adjacent normal tissues. Subsequently, circ_0000442 was found to acted as the sponge of miR-148b-3p in breast cancer cells, thus exerting the tumor-suppressive effects. In the subsequent mechanism study, results showed that miR-148b-3p directly targeted PTEN, a well-known tumor suppressor which negatively regulats PI3K/Akt pathway, thus promoting tumor growth in breast cancer. Overall, this study for the first time identified the tumor-suppressive role of circ_0000442 in breast cancer and found PTEN as a novel direct target of miR-148b-3p. The regulatory role of circ_0000442/miR-148b-3p/PTEN/PI3K/Akt axis was preliminarily confirmed in breast cancer cells and mouse models. These findings suggest an important progress in our standing of breast cancer and lay the foundation for the further function, diagnosis, therapy and prognosis research of circular RNAs in breast cancer.

Ectodermal-neural cortex 1 as a novel biomarker predicts poor prognosis and induces metastasis in breast cancer by promoting Wnt/β-catenin pathway

Breast cancer, as the most common malignancy, is the second leading cause of cancer‐related death in women. One of the kelch family member ENC1 is involved in various pathophysiologic processes. But the role of ENC1 in breast cancer has not been investigated. The present study value the feature, clinical significance and the molecular mechanisms of ENC1 in breast cancer. The expression and prognosis value of ENC1 expression among breast cancer and normal breast tissue were investigated in The Cancer Genome Atlas database and human samples. ENC1 was knockdown to explore its function in various breast cancer cell lines. Western blot was performed to explore the potential molecular mechanisms. We observed that ENC1 was overexpressed in breast cancer tissues. ENC1 overexpression was associated with high metastasis and predicted a poor prognosis in patients with breast cancer. ENC1 Knockdown inhibits the growth, clone formation, migration and invasion of breast cancer cells. Mechanism analysis revealed ENC1 was strong associated with the metastasis by modulating β‐catenin pathway. Our study emphasizes that ENC1 is a potential prognostic and metastasis‐related marker of breast cancer, and may function as a possible therapeutic target against breast cancer.

Rlip Depletion Suppresses Growth of Breast Cancer

RLIP76 (RAL-binding protein-1, Rlip) is a stress-protective mercapturic-acid-pathway transporter protein that also plays a key role in regulating clathrin-dependent endocytosis as a Ral effector. Targeted inhibition or depletion of Rlip causes regression of xenografts of many cancers and is capable of abrogating tumor formation in p53-null mice. This is associated with the reversion of the abnormal methylomic profile of p53-null mice to wild-type. In a query of The Cancer Genome Atlas (TCGA) databases, we found that Rlip expression was associated with poor survival and with significant differences in the frequencies of PIK3CA mutation, MYC amplification, and CDKN2A/B deletion, which were the most commonly mutated, amplified, and deleted genes, respectively, among TCGA breast cancer patients. We conducted the present study to further examine the effects of Rlip inhibition and to evaluate the in vitro and in vivo efficacy in breast cancer. Using immunogold electron microscopy, we found that plasma-membrane Rlip was accessible to cell-surface antibodies in the MCF7 (ER+) breast cancer cell line. Rlip depletion resulted in decreased survival of MCF7 and MDA-MB-231 cells and increased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positivity and DNA laddering, indicating apoptotic cell death. Additionally, in vitro knockdown of Rlip inhibited EGF endocytosis and WNT/MAPK signaling. Xenograft studies in nude mice showed regression of breast cancer via antisense-mediated depletion of Rlip mRNA as well as by anti-Rlip antibody. Finally, knockdown of Rlip by antisense locked nucleic acid oligonucleotides increased markers for apoptotic signaling and decreased markers for proliferation, angiogenesis, and cell cycling in MCF7 and MDA-MB-231luc xenografts. Our findings validate Rlip as an attractive target in breast cancer.

Combination Strategies of Checkpoint Immunotherapy in Metastatic Breast Cancer

Checkpoint immunotherapy is emerging as a new therapeutic approach for metastatic breast cancer. Monotherapy of immunoagents against PD1/PD-L1 or CTLA-4 has shown little efficacy in these patients. Recently, to determine the optimal use of immunotherapy, there has been a rapid expansion in the number of clinical trials developing immunotherapy combinations. These combination therapeutic approaches can enhance various aspects of cancer immunity, such as tumor antigenicity or intratumor T cell infiltration, which provides a theoretical basis for combining them with checkpoint immunotherapy to achieve synergistic effects. Here, we review the available data and ongoing efforts to establish the safety and efficacy of immunoagents in combination with chemotherapy, radiotherapy, HER2-targeted therapy, CDK4/6 inhibitors, PARP inhibitors, and another checkpoint immunoagents.

Effectiveness and Tolerability of Nab-paclitaxel in Younger versus Elderly Patients With Metastatic HR-positive/HER2-negative Breast Cancer: Results From the Noninterventional, Prospective Study NABUCCO

BACKGROUND

There are only scarce data on treatment of elderly patients with nab-paclitaxel for metastatic breast cancer, especially from the real-world setting. Here we present data from the noninterventional study NABUCCO with special focus on taxane-induced peripheral neuropathy (TIPN) in younger and elderly patients.

PATIENTS AND METHODS

A total of 407 patients with HR-positive/HER2-negative metastatic breast cancer were enrolled between April 2012 and April 2015 into the prospective, multicenter, noninterventional study NABUCCO. Details on effectiveness, tolerability, and safety of nab-paclitaxel were evaluated for younger (<70 years) and elderly (≥70 years) patients.

RESULTS

Neither median time to progression (TTP, younger 6.0 months, 95% confidence interval [CI], 5.5-7.1; elderly 6.9 months, 95% CI, 5.5-8.6) nor median overall survival (younger 16.4 months, 95% CI, 14.2-18.1; elderly 14.5 months, 95% CI, 11.9-17.4) differed by age group, also not in view of prior treatments. A multivariate regression model revealed that age did not significantly influence the TTP. TIPN was reported by 49.0% younger (44.3% common terminology criteria for adverse events [CTCAE] grade 1/2, 4.7% grade 3/4) and 45.8% elderly patients (41.1% CTCAE grade 1/2, 4.7% grade 3/4). The cumulative nab-paclitaxel dose did not correlate with the severity/grading of TIPN.

CONCLUSION

Treatment with nab-paclitaxel in first- or further-line of metastatic HR-positive/HER2-negative breast cancer resulted in similar effectiveness and safety, irrespective of age. Therefore, nab-paclitaxel is a valid treatment option for elderly and partially heavily pretreated patients. However, incidence of TIPN is high, influencing the patients' quality of life. A close monitoring and awareness for early TIPN symptoms is warranted.

circKDM4C suppresses tumor progression and attenuates doxorubicin resistance by regulating miR-548p/PBLD axis in breast cancer

Increasing evidence has indicated that circular RNAs (circRNAs) play a critical role in cancer development. However, only a small number of circRNAs have been experimentally validated and functionally annotated. In this study, using a high-throughput microarray assay, we identified a novel circRNA, circKDM4C, which was downregulated in breast cancer tissues with metastasis. Furthermore, we analyzed a cohort of breast cancer patients and found that circKDM4C expression was decreased in breast cancer tissues, and lower circKDM4C expression was associated with poor prognosis and metastasis in breast cancer. Functionally, we demonstrated that circKDM4C significantly repressed breast cancer proliferation, metastasis, and doxorubicin resistance in vitro and in vivo. Mechanistically, using a dual-luciferase activity assay and AGO2 RNA immunoprecipitation, circKDM4C was identified as a miR-548p sponge. We also found that PBLD was a direct target of miR-548p, which functioned as a tumor suppressor in breast cancer. Moreover, miR-548p overexpression was able to reverse the circKDM4C-induced attenuation of malignant phenotypes and elevated expression of PBLD in breast cancer cells. Taken together, our data indicate that circKDM4C might have considerable potential as a prognostic biomarker in breast cancer, and support the notion that therapeutic targeting of circKDM4C/miR-548p/PBLD axis may be a promising treatment approach for breast cancer patients.

The pan-therapeutic resistance of disseminated tumor cells: Role of phenotypic plasticity and the metastatic microenvironment

Cancer metastasis is the leading cause of mortality in patients with solid tumors. The majority of these deaths are associated with metastatic disease that occurs after a period of clinical remission, anywhere from months to decades following removal of the primary mass. This dormancy is prominent in cancers of the breast and prostate among others, leaving the survivors uncertain about their longer-term prognosis. The most daunting aspect of this dormancy and re-emergence is that the micrometastases in particular, and even large lethal outgrowths are often show resistance to agents to which they have not been exposed. This suggests that in addition to specific mutations that target single agents, there also exist adaptive mechanisms that provide this pan-resistance. Potential molecular underpinnings of which are the topic of this review.

Identification of Prolyl isomerase Pin1 as a novel positive regulator of YAP/TAZ in breast cancer cells

The Hippo signalling pathway plays very important roles in tumorigenesis, metastasis, organ size control, and drug resistance. Although, it has been shown that the two major components of Hippo pathway, YAP and TAZ, play very crucial role in tumorigenesis and drug resistance, the exact molecular mechanisms are still unknown. Recently, we have shown that the prolyl isomerase Pin1 regulates the activity of Hippo pathway through interaction with Hippo component LATS kinase. Thus we asked if Pin1 is also able to interact with other Hippo pathway components. Therefore, in order to investigate whether Pin1 can interacts with other components of the Hippo pathway, we performed GST-pull down and co-immunoprecipitation (Co-IP) assays and have identified two Hippo components YAP and TAZ oncoproteins as novel binding partner of Pin1. We found that Pin1 interacts with YAP/TAZ in a phosphorylation-independent manner and WW domain of Pin1 is necessary for this interaction. Moreover, by using real time qRT-PCR, Cycloheximide chase, luciferase reporter, cell viability and soft agar assays, we have shown that Pin1 increases the tumorigenic and drug-resistant activity of YAP/TAZ through stabilization of YAP/TAZ at protein levels. Together, we have identified Pin1 as a novel positive regulator of YAP/TAZ in tumorigenesis and drug resistance of breast cancer cells. These findings will provide a significant contribution for targeting the Pin1-YAP/TAZ signaling for the successful treatment of tumorigenesis and drug resistance of breast and other cancers in the future.

Downregulated GBX2 gene suppresses proliferation, invasion and angiogenesis of breast cancer cells through inhibiting the Wnt/β-catenin signaling pathway

OBJECTIVE

Gastrulation brain homeobox 2 (GBX2), a gene involved in mid/hindbrain region, has been revealed as one of the oncogene associated with certain cancers, as an example being prostate cancer. However, despite years of worldwide research, the underlying mechanism of GBX2 as well as its significance in breast cancer still remains unclear. Therefore, the present study evaluates the abilities of GBX gene silencing providing for the proliferation, invasion and angiogenesis of breast cancer cells by way of the Wnt/β-catenin signaling pathway.

METHODS

We employed a microarray analysis to screen out differentially expressed genes relative to breast cancer. Moreover, we retrieved GBX2 expression in breast cancer to find out the relationship between GBX2 expression and prognosis in breast cancer. We performed RT-qPCR to screen out cell lines with high GBX2 expression. Subsequently, both RT-qPCR and western blot analysis were employed so as to measure the combination of the mRNA and protein expressions of GBX2, β-catenin, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, and MMP-9. The effect that GBX2 gene silencing and the Wnt/β-catenin signaling pathway had on cell proliferation, invasion, angiogenesis, and tumorigenic ability were evaluated.

RESULTS

GBX2 gene was also identified having played a role in breast cancer development due to its association with the Wnt/β-catenin signaling pathway. GBX2 gene silencing was found to be an inhibitor for the mRNA and protein expressions regulating β-catenin, VEGF, MMP-2, and MMP-9. Cell proliferation, invasion, angiogenesis, as well as tumorigenic ability in breast cancer were investigated and found to have been suppressed by the GBX2 gene silencing or inactivation of the Wnt/β-catenin signaling pathway.

CONCLUSION

The study has made an attempt to provide evidence to the idea that GBX2 gene silencing has an inhibition effect on the proliferation, invasion and angiogenesis of the breast cancer cells by inhibiting the activation of the Wnt/β-catenin signaling pathway.

An Electronic Patient-Reported Outcome Tool for the FACT-B (Functional Assessment of Cancer Therapy-Breast) Questionnaire for Measuring the Health-Related Quality of Life in Patients With Breast Cancer: Reliability Study

Background

The most frequent malignant disease in women is breast cancer. In the metastatic setting, quality of life is the primary therapeutic goal, and systematic treatment has only a limited effect on survival rates; therefore, the concept of the health-related quality of life (HRQoL) and measurement of patient-reported outcomes (PROs) are gaining more and more importance in the therapy setting of diseases such as breast cancer. One of the frequently used questionnaires for measuring the HRQoL in patients with breast cancer is the Functional Assessment of Cancer Therapy-Breast (FACT-B). Currently, paper-based surveys still predominate, as only a few reliable and validated electronic-based questionnaires are available. ePRO tools for the FACT-B questionnaire with proven reliability are missing so far.

Objective

The aim of this study was to analyze the reliability of tablet-based measurement of FACT-B in the German language in adjuvant (curative) and metastatic breast cancer patients.

Methods

Paper- and tablet-based questionnaires were completed by a total of 106 female adjuvant and metastatic breast cancer patients. All patients were required to complete the electronically based (ePRO) and paper-based version of the FACT-B. A frequency analysis was performed to determine descriptive sociodemographic characteristics. Both dimensions of reliability (parallel forms reliability using Wilcoxon test and test of internal consistency using Spearman ρ) and agreement rates for single items, Kendall tau for each subscale, and total score were analyzed.

Results

High correlations were shown for both dimensions of reliability (parallel forms reliability and internal consistency) in the patients’ response behavior between paper-based and electronically based questionnaires. Regarding the reliability test of parallel forms, no significant differences were found in 35 of 37 single items, while significant correlations in the test for consistency were found in all 37 single items, in all 5 sum individual item subscale scores, as well as in total FACT-B score.

Conclusions

The ePRO version of the FACT-B questionnaire is reliable for patients with breast cancer in both adjuvant and metastatic settings, showing highly significant correlations with the paper-based version in almost all questions all subscales and the total score.

β-caryophyllene enhances the transcriptional upregulation of cholesterol biosynthesis in breast cancer cells

β-caryophyllene (BCP) exhibits anti-proliferative properties in cancer cells. Here, we examine the hypothesis that BCP induces membrane remodeling. Our data show that high concentrations of BCP increase membrane permeability of human breast cells (hBrC) causing detachment and cell death. At a sub-lethal concentration of BCP, we show that BCP induces a striking upregulation of genes involved in cholesterol biosynthesis, including the gene that encodes for HMGCoA reductase (HMGCR), the rate-determining step in cholesterol biosynthesis. In addition, stearoyl-CoA desaturase (SCD) is also upregulated which would lead to the enhanced formation of monounsaturated fatty acids, specifically oleate and palmitoleate from stearoyl CoA and palmitoyl CoA, respectively. These fatty acids are major components of membrane phospholipids and cholesterol esters. Together, these data suggest that cells respond to BCP by increasing the synthesis of components found in membranes. These responses could be viewed as a repair mechanism and/or as a mechanism to mount resistance to the cytotoxic effect of BCP. Blocking HMGCR activity enhances the cytotoxicity of BCP, suggesting that BCP may provide an additional therapeutic tool in controlling breast cancer cell growth.

Impeding Circulating Tumor Cell Reseeding Decelerates Metastatic Progression and Potentiates Chemotherapy

Circulating tumor cells (CTCs) are commonly detected in the systemic blood of patients with cancer with metastatic tumors. However, the mechanisms controlling the viability of cancer cells in blood and length of time spent in circulation, as well as their potential for generating additional tumors are still undefined. Here, it is demonstrated that CX3CR1, a chemokine receptor, drives reseeding of breast CTCs to multiple organs. Antagonizing this receptor dramatically impairs the progression of breast cancer cells in a relevant model of human metastatic disease, by affecting both tumor growth and numerical expansion. Notably, therapeutic targeting of CX3CR1 prolongs CTC permanence in the blood, both promoting their spontaneous demise by apoptosis and counteracting metastatic reseeding. These effects lead to containment of metastatic progression and extended survival. Finally, targeting CX3CR1 improves blood exposure of CTCs to doxorubicin and in combination with docetaxel shows synergistic effects in containing overall tumor burden. IMPLICATIONS: The current findings shed light on CTCs reseeding dynamics and support the development of CX3CR1 antagonism as a viable strategy to counteract metastatic progression.

Leptin induces epithelial-to-mesenchymal transition via activation of the ERK signaling pathway in lung cancer cells

Previous studies revealed that leptin induces the growth and proliferation and inhibits the apoptosis of lung cancer cells. However, the effect of leptin on epithelial-to-mesenchymal transition (EMT) is not yet clear. In the present study, the effect of leptin on EMT was investigated as well as its underlying mechanisms in A549 cells. The ability of leptin to induce EMT was investigated by microscopic examination and western blotting. The impacts of leptin on cell migration, invasion and tumorigenesis were evaluated by wound healing, Transwell and colony formation assays, respectively. It was demonstrated that leptin induced EMT-associated morphological changes, namely a decrease in cell-cell contact and a more elongated morphological shape. Leptin decreased the expression levels of epithelial phenotype markers E-cadherin and keratin, increased the expression of mesenchymal phenotype marker Vimentin, and raised the expression of EMT-induced transcription factor ZEB-1. In addition, leptin activated the extracellular signal regulated kinase (ERK) signaling pathway and did not affect the activation of the protein kinase B signaling pathway in A549 cells. Leptin also promoted EMT-induced migration, invasion and tumorigenesis in vitro in A549 cells. The present study provides evidence that leptin induced EMT via the activation of the ERK signaling pathway and increased EMT-induced tumor phenotypes in lung cancer cells. These findings suggest that leptin may be a promising target for lung cancer treatment through the regulation of EMT.

Mechanoresponsive stem cells to target cancer metastases through biophysical cues

Despite decades of effort, little progress has been made to improve the treatment of cancer metastases. To leverage the central role of the mechanoenvironment in cancer metastasis, we present a mechanoresponsive cell system (MRCS) to selectively identify and treat cancer metastases by targeting the specific biophysical cues in the tumor niche in vivo. Our MRCS uses mechanosensitive promoter-driven mesenchymal stem cell (MSC)-based vectors, which selectively home to and target cancer metastases in response to specific mechanical cues to deliver therapeutics to effectively kill cancer cells, as demonstrated in a metastatic breast cancer mouse model. Our data suggest a strong correlation between collagen cross-linking and increased tissue stiffness at the metastatic sites, where our MRCS is specifically activated by the specific cancer-associated mechano-cues. MRCS has markedly reduced deleterious effects compared to MSCs constitutively expressing therapeutics. MRCS indicates that biophysical cues, specifically matrix stiffness, are appealing targets for cancer treatment due to their long persistence in the body (measured in years), making them refractory to the development of resistance to treatment. Our MRCS can serve as a platform for future diagnostics and therapies targeting aberrant tissue stiffness in conditions such as cancer and fibrotic diseases, and it should help to elucidate mechanobiology and reveal what cells "feel" in the microenvironment in vivo.

Metastatic Breast Cancer Treated with Lapatinib with a Prolonged Benefit: A Case Report and a Review of Therapeutic Options Available

A 53-year-old woman was treated, after trastuzumab progression of HER2-positive metastatic disease, with capecitabine plus lapatinib and subsequently with lapatinib alone. To date, she has had persistent remission of disease since 2009.

Construction of Human Immune and Naive scFv Libraries

Antibody phage display is the most commonly used in vitro selection technology for the generation of human recombinant antibodies and has yielded thousands of useful antibodies for research, diagnostics, and therapy. The prerequisite for successful generation of antibodies using phage display is the construction of high-quality antibody gene libraries. Here, we give the detailed methods for the construction of human immune and naive scFv gene libraries.

Association between gene expression profile of the primary tumor and chemotherapy response of metastatic breast cancer

Background

To better predict the likelihood of response to chemotherapy, we have conducted a study comparing the gene expression patterns of primary tumours with their corresponding response to systemic chemotherapy in the metastatic setting.

Methods

mRNA expression profiles of breast carcinomas of patients that later developed distant metastases were analyzed using supervised and non-supervised classification techniques to identify predictors of response to chemotherapy. The top differentially expressed genes between the responders and non-responders were identified and further explored. An independent dataset which was generated to predict response to neo-adjuvant CT was utilized for the purpose of validation. Response to chemotherapy was also correlated to the clinicopathologic characteristics, molecular subtypes, metastatic behavior and survival outcomes.

Results

Anthracycline containing regimens were the most common first line treatment (58.4%), followed by non-anthracycline/non-taxane containing (25.8%) and taxane containing (15.7%) regimens. Response was achieved in 41.6% of the patients to the first line CT and in 21.8% to second line CT. Response was not found to be significantly correlated to tumour type, grade, lymph node status, ER and PR status. Patients with HER2+ tumours showed better response to anthracycline containing therapy (p: 0.002). Response to first and second line chemotherapy did not differ among gene expression based molecular subtypes (p: 0.236 and p: 0.20). Using supervised classification, a 14 gene response classifier was identified. This 14-gene predictor could successfully predict the likelihood of better response to first and second line CT (p: <.0001 and p: 0.761, respectively) in the training set. However, the predictive value of this gene set in data of response to neoadjuvant chemotherapy could not be validated.

Conclusions

To our knowledge, this is the first study revealing the relation between gene expression profiles of the primary tumours and their chemotherapy responsiveness in the metastatic setting. In contrast to the findings for neoadjuvant chemotherapy treatment, there was no association of molecular subtype with response to chemotherapy in the metastatic setting. Using supervised classification, we identified a classifier of chemotherapy response; however, we could not validate this classifier using neoadjuvant response data.

Trial registration

Non applicable. Subjects were retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3691-9) contains supplementary material, which is available to authorized users.

Transcription factor c-Myb inhibits breast cancer lung metastasis by suppression of tumor cell seeding

Metastasis accounts for most of cancer-related deaths. Paracrine signaling between tumor cells and the stroma induces changes in the tumor microenvironment required for metastasis. Transcription factor c-Myb was associated with breast cancer (BC) progression but its role in metastasis remains unclear. Here we show that increased c-Myb expression in BC cells inhibits spontaneous lung metastasis through impaired tumor cell extravasation. On contrary, BC cells with increased lung metastatic capacity exhibited low c-Myb levels. We identified a specific inflammatory signature, including Ccl2 chemokine, that was expressed in lung metastatic cells but was suppressed in tumor cells with higher c-Myb levels. Tumor cell-derived Ccl2 expression facilitated lung metastasis and rescued trans-endothelial migration of c-Myb overexpressing cells. Clinical data show that the identified inflammatory signature, together with a MYB expression, predicts lung metastasis relapse in BC patients. These results demonstrate that the c-Myb-regulated transcriptional program in BCs results in a blunted inflammatory response and consequently suppresses lung metastasis.

Migration Rate Inhibition of Breast Cancer Cells Treated by Caffeic Acid and Caffeic Acid Phenethyl Ester: An In Vitro Comparison Study

One of the deadliest cancers among women is a breast cancer. Research has shown that two natural substances occurring in propolis, caffeic acid (CA) and caffeic acid phenethyl ester (CAPE), have significant anticancer effects. The purpose of our in vitro study was to compare cytotoxic activity and migration rate inhibition using CA and CAPE (doses of 50 and 100 µm) against triple-negative, MDA-MB-231 breast adenocarcinoma line cells, drawn from Caucasian women. Viability was measured by XTT-NR-SRB assay (Tetrazolium hydroxide-Neutral Red-Sulforhodamine B) for 24 h and 48 h periods. Cell migration for wound healing assay was taken for 0 h, 8 h, 16 h, and 24 h periods. CAPE displayed more than two times higher cytotoxicity against MDA-MB-231 cells. IC₅₀ values for the XTT assay were as follows: CA for 24 h and 48 h were 150.94 µM and 108.42 µM, respectively, while CAPE was 68.82 µM for 24 h and 55.79 µM for 48 h. For the NR assay: CA was 135.85 µM at 24 h and 103.23 µM at 48 h, while CAPE was 64.04 µM at 24 h and 53.25 µM at 48 h. For the SRB assay: CA at 24 h was 139.80 µM and at 48 h 103.98 µM, while CAPE was 66.86 µM at 24 h and 47.73 µM at 48 h. Both agents suspended the migration rate; however, CAPE displayed better activity. Notably, for the 100 µM CAPE dose, motility of the tested breast carcinoma cells was halted.