EGFR signaling in breast cancer: bad to the bone

Cross-Talk between NOK and EGFR: Juxtamembrane and Kinase domain interactions enhancing STAT3/5 signaling in breast cancer tumorigenesis

Epidermal growth factor receptor (EGFR) plays an important role in the regulation of cell proliferation and migration [1]. It forms a homodimer or heterodimer with other ErbB receptor family members to activate downstream signaling. Emerging evidence indicates that the EGFR activity and downstream signaling are regulated by other proteins except its family members during tumorigenesis. Hence, investigating the diverse partnership profiles of EGFR is crucial for elucidating the mechanisms underlying EGFR-mediated actions in tumors, which in turn can guide the development of targeted therapeutic strategies. Here we report that NOK (also known as STYK1), a novel tyrosine kinase cross-talks with EGFR to promote tumorigenesis and metastasis of breast cancer cells. We found that NOK directly interacted with EGFR and formed a heterodimer complex in a manner of cross interaction via their juxtamembrane (JM) domains and kinase domains. Depletion of NOK impaired, but over-expression of NOK increased, the phosphorylation of EGFR. NOK enhanced EGF-induced phosphorylation of STAT3 and STAT5 via its juxtamembrane (JM) domain in promoting the proliferation and migration of breast cancer cells. Overexpression of NOK and EGFR synergistically induced the tumorigenesis of NIH-3T3 normal cells. We demonstrated that co-expression of NOK and EGFR correlated with tumor malignant stages in breast cancer patients. Our finding introduces a new cross interaction manner of EGFR-NOK via juxtamembrane (JM) domains and kinase domains, uncovers a mechanism by which NOK coordinates EGFR to enhance EGF-STAT3/5 signaling during tumorigenesis and metastasis, and proposes a potential strategy for targeting NOK-EGFR in breast cancer treatment.

EGFR does not directly interact with cortical actin: A SRRF'n'TIRF study

The epidermal growth factor receptor (EGFR) governs pivotal signaling pathways in cell proliferation and survival, with mutations implicated in numerous cancers. The organization of EGFR on the plasma membrane (PM) is influenced by the lipids and the cortical actin (CA) cytoskeleton. Despite the presence of a putative actin-binding domain (ABD) spanning 13 residues, a direct interaction between EGFR and CA has not been definitively established. While disrupting the cytoskeleton can impact EGFR behavior, suggesting a connection, the influence of the static actin cytoskeleton has been found to be indirect. Here, we investigate the potential interaction between EGFR and CA, as well as the extent to which CA regulates EGFR's distribution on the PM using SRRF'n'TIRF, a spatiotemporal super-resolution microscopy technique that provides sub-100 nm resolution and ms-scale dynamics from the same data set. To label CA, we constructed PMT-mEGFP-F-tractin, which combines an inner leaflet targeting domain PMT, fluorescent probe mEGFP, and the actin-binding protein F-tractin. In addition to EGFR-mEGFP, we included two control constructs: 1) an ABD deletion mutant, EGFRΔABD-mEGFP serving as a negative control and 2) EGFR-mApple-F-tractin, where F-tractin is fused to the C-terminus of EGFR-mApple, serving as the positive control. We find that EGFR-mEGFP and EGFRΔABD-mEGFP show similar membrane dynamics, implying that EGFR-mEGFP dynamics and organization are independent of CA. EGFR dynamics show CA dependence when F-tractin is anchored to the cytoplasmic tail. Together, our results demonstrate that EGFR does not directly interact with the CA in its resting and activated state.

Survival prediction and analysis of drug-resistance genes in HER2-positive breast cancer

Despite the approval of several therapeutic agents for HER2-positive breast cancer, drug resistance remains a significant challenge, hindering the patient's prognosis. Thus, our study aimed to establish a risk model to predict the prognosis of patients and identify key genes regulating drug resistance in HER2-positive breast cancer. Utilizing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), a predictive model was constructed based on 5 drug resistance-related genes, which demonstrated a notable capacity to indicate the survival rates of patients. Besides, through eccDNA and transcriptome sequencing of drug-sensitive and resistant cancer cells, 3 significant DEGs were identified: MED1, MED24, and NMD3. Among them, MED1 showed the most significant elevation in drug-resistance cells, highlighting its crucial role in mediating drug resistance. MED1 may serve as a valuable target for alleviating drug resistance in HER2-positive breast cancer.

Exploring ncRNA-mediated regulation of EGFR signalling in glioblastoma: From mechanisms to therapeutics

Glioblastoma (GBM) is the most prevalent and deadly primary brain tumor type, with a discouragingly low survival rate and few effective treatments. An important function of the EGFR signalling pathway in the development of GBM is to affect tumor proliferation, persistence, and treatment resistance. Advances in molecular biology in the last several years have shown how important ncRNAs are for controlling a wide range of biological activities, including cancer progression and development. NcRNAs have become important post-transcriptional regulators of gene expression, and they may affect the EGFR pathway by either directly targeting EGFR or by modifying important transcription factors and downstream signalling molecules. The EGFR pathway is aberrantly activated in response to the dysregulation of certain ncRNAs, which has been linked to GBM carcinogenesis, treatment resistance, and unfavourable patient outcomes. We review the literature on miRNAs, circRNAs and lncRNAs that are implicated in the regulation of EGFR signalling in GBM, discussing their mechanisms of action, interactions with the signalling pathway, and implications for GBM therapy. Furthermore, we explore the potential of ncRNA-based strategies to overcome resistance to EGFR-targeted therapies, including the use of ncRNA mimics or inhibitors to modulate the activity of key regulators within the pathway.

Targeting epidermal growth factor receptor and its downstream signaling pathways by natural products: A mechanistic insight

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase (RTK) that maintains normal tissues and cell signaling pathways. EGFR is overactivated and overexpressed in many malignancies, including breast, lung, pancreatic, and kidney. Further, the EGFR gene mutations and protein overexpression activate downstream signaling pathways in cancerous cells, stimulating the growth, survival, resistance to apoptosis, and progression of tumors. Anti-EGFR therapy is the potential approach for treating malignancies and has demonstrated clinical success in treating specific cancers. The recent report suggests most of the clinically used EGFR tyrosine kinase inhibitors developed resistance to the cancer cells. This perspective provides a brief overview of EGFR and its implications in cancer. We have summarized natural products-derived anticancer compounds with the mechanistic basis of tumor inhibition via the EGFR pathway. We propose that developing natural lead molecules into new anticancer agents has a bright future after clinical investigation.

RSV Induces Activation of Intracellular EGFR on the Mitochondrial Membrane for Virus Propagation

Respiratory syncytial virus (RSV) infects people of all ages and is one of the most common causative agents of lower respiratory tract infections, such as pneumonia, especially in infants under one year of age. However, no direct treatment has been developed for RSV infections. Maintenance of mitochondrial homeostasis and epidermal growth factor receptor (EGFR) activity is important for human cell growth. This study reported that RSV infection maintained the total cellular ATP levels and promoted the intracellular activity of EGFR to replicate RSV. RSV activates the intracellular EGFR-mediated cell survival signaling cascade and maintains mitochondrial EGFR expression for viral production during early events after infection. The approved EGFR inhibitor, vandetanib, markedly reduces RSV propagation, suggesting that EGFR is an attractive host target for RSV therapeutics. Our results suggest that RSV infection maintains cellular ATP levels and promotes the activation of intracellular EGFR in the mitochondrial membrane, significantly contributing to robust RSV propagation.

Role of Virus-Induced EGFR Trafficking in Proviral Functions

Since its discovery in the early 1980s, the epidermal growth factor receptor (EGFR) has emerged as a pivotal and multifaceted player in elucidating the intricate mechanisms underlying various human diseases and their associations with cell survival, proliferation, and cellular homeostasis. Recent advancements in research have underscored the profound and multifaceted role of EGFR in viral infections, highlighting its involvement in viral entry, replication, and the subversion of host immune responses. In this regard, the importance of EGFR trafficking has also been highlighted in recent studies. The dynamic relocation of EGFR to diverse intracellular organelles, including endosomes, lysosomes, mitochondria, and even the nucleus, is a central feature of its functionality in diverse contexts. This dynamic intracellular trafficking is not merely a passive process but an orchestrated symphony, facilitating EGFR involvement in various cellular pathways and interactions with viral components. Furthermore, EGFR, which is initially anchored on the plasma membrane, serves as a linchpin orchestrating viral entry processes, a crucial early step in the viral life cycle. The role of EGFR in this context is highly context-dependent and varies among viruses. Here, we present a comprehensive summary of the current state of knowledge regarding the intricate interactions between EGFR and viruses. These interactions are fundamental for successful propagation of a wide array of viral species and affect viral pathogenesis and host responses. Understanding EGFR significance in both normal cellular processes and viral infections may not only help develop innovative antiviral therapies but also provide a deeper understanding of the intricate roles of EGFR signaling in infectious diseases.

Machine Learning-Based Approach to Developing Potent EGFR Inhibitors for Breast Cancer-Design, Synthesis, and In Vitro Evaluation

The epidermal growth factor receptor (EGFR) is vital for regulating cellular functions, including cell division, migration, survival, apoptosis, angiogenesis, and cancer. EGFR overexpression is an ideal target for anticancer drug development as it is absent from normal tissues, marking it as tumor-specific. Unfortunately, the development of medication resistance limits the therapeutic efficacy of the currently approved EGFR inhibitors, indicating the need for further development. Herein, a machine learning-based application that predicts the bioactivity of novel EGFR inhibitors is presented. Clustering of the EGFR small-molecule inhibitor (∼9000 compounds) library showed that N-substituted quinazolin-4-amine-based compounds made up the largest cluster of EGFR inhibitors (∼2500 compounds). Taking advantage of this finding, rational drug design was used to design a novel series of 4-anilinoquinazoline-based EGFR inhibitors, which were first tested by the developed artificial intelligence application, and only the compounds which were predicted to be active were then chosen to be synthesized. This led to the synthesis of 18 novel compounds, which were subsequently evaluated for cytotoxicity and EGFR inhibitory activity. Among the tested compounds, compound 9 demonstrated the most potent antiproliferative activity, with 2.50 and 1.96 μM activity over MCF-7 and MDA-MB-231 cancer cell lines, respectively. Moreover, compound 9 displayed an EGFR inhibitory activity of 2.53 nM and promising apoptotic results, marking it a potential candidate for breast cancer therapy.

Repositioning Cannabinoids and Terpenes as Novel EGFR-TKIs Candidates for Targeted Therapy Against Cancer: A virtual screening model using CADD and biophysical simulations

This study examines the potential of Cannabis sativa L. plants to be repurposed as therapeutic agents for cancer treatment through designing of hybrid Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). A set of 50 phytochemicals was taken from Cannabinoids and Terpenes and subjected for screening using Semi-flexible and Flexible Molecular Docking methods, MM-GBSA free binding energy computations, and pharmacokinetic/pharmacodynamic (ADME-Tox) predictions. Nine promising phytochemicals, Cannabidiolic acid (CBDA), Cannabidiol (CBD), Tetrahydrocannabivarin (THCV), Dronabinol (Δ-9-THC), Delta-8-Tetrahydrocannabinol (Δ-8-THC), Cannabicyclol (CBL), Delta9-tetrahydrocannabinolic acid (THCA), Beta-Caryophyllene (BCP), and Gamma-Elemene (γ-Ele) were identified as potential EGFR-TKIs natural product candidates for cancer therapy. To further validate these findings, a set of Molecular Dynamics simulations were conducted over a 200 ns trajectory. This hybrid early drug discovery screening strategy has the potential to yield a new generation of EGFR-TKIs based on natural cannabis products, suitable for cancer therapy. In addition, the application of this computational strategy in the virtual screening of both natural and synthetic chemical libraries could support the discovery of a wide range of lead drug agents to address numerous diseases.

EGFR Suppression Inhibits the Sphere Formation of MCF7 Cells Overexpressing EGFR

The epidermal growth factor receptor (EGFR) is an oncogenic tyrosine kinase that is involved in tumor initiation and progression, making EGFR inhibitors and monoclonal antibodies to this receptor essential for anti-tumor therapy. We have previously shown that EGFR transgene expression in the human breast adenocarcinoma cell line MCF7 (MCF7-EGFR) stimulates the 3D spheroid-like growth. The primary focus of our present work was to investigate whether EGFR inhibition could affect the assembly of spheroids or lead to the destruction of pre-existing spheroids. We compared the effects of anti-EGFR siRNA, the anti-EGFR monoclonal antibody cetuximab, and the tyrosine kinase inhibitor AG1478 on dissociated and spheroid MCF7-EGFR cells. MCF7-EGFR cells were found to have a 2.5-fold higher sensitivity towards the cytotoxic effects of cetuximab and AG1478 compared with the parental MCF7 cell line. The suppression of EGFR mRNA with siRNA was found to reduce the sphere formation, whereas treating the pre-existing spheroids had no such effect. Treatment of dissociated spheroids with cetuximab and AG1478 was also found to inhibit the MCF7-EGFR sphere formation. We suggest that EGFR expression is important, at least, during the spheroid formation stage. The transition of a MCF7wt adherent cell culture to MCF7-EGFR spheroids was accompanied by a considerable increase in N-cadherin adhesion proteins. The level of N-cadherin decreased when MCF7-EGFR cells were treated with siRNA and cetuximab. Thus, we have demonstrated that N-cadherin is involved in the EGFR-dependent formation of MCF7-EGFR spheroids. Accordingly, MCF7-EGFR spheroids can be considered a suitable model for studying aggressive hormone-positive breast tumors.

Transport Mechanism for Nuclear Localization of Irradiation-Activated EGFR Measured by Single-Molecule Pull-Down Assay

Nuclear transport of epidermal growth factor receptor (EGFR) is considered to be a key cause of radiation resistance in cancer therapy. Here, we showed that irradiation-activated EGFR binds to the nuclear transport protein karyopherin alpha (KPNA) rather than karyopherin subunit beta 1 (KPNB1), through a single-molecule pull-down assay, which allows measurement of the binding affinity by single proteins in cell lysate without an additional purification step. We also obtained kinetic parameters for the binding between the phosphorylated nuclear localization signal (NLS) peptide of EGFR (⁶⁴⁵RRRHIVRKRpTLRR⁶⁵⁷) and KPNA. This observation may help developing small molecules to modulate nuclear transport, which potentially reduces the radiation resistance during irradiation therapy.

The role of the NDRG1 in the pathogenesis and treatment of breast cancer

Breast cancer (BC) is the leading cause of cancer death in women. This disease is heterogeneous, with clinical subtypes being estrogen receptor-α (ER-α) positive, having human epidermal growth factor receptor 2 (HER2) overexpression, or being triple-negative for ER-α, progesterone receptor, and HER2 (TNBC). The ER-α positive and HER2 overexpressing tumors can be treated with agents targeting these proteins, including tamoxifen and pertuzumab, respectively. Despite these treatments, resistance and metastasis are problematic, while TNBC is challenging to treat due to the lack of suitable targets. Many studies examining BC and other tumors indicate a role for N-myc downstream-regulated gene-1 (NDRG1) as a metastasis suppressor. The ability of NDRG1 to inhibit metastasis is due, in part, to the inhibition of the initial step in metastasis, namely the epithelial-to-mesenchymal transition. Paradoxically, there are also reports of NDRG1 playing a pro-oncogenic role in BC pathogenesis. The oncogenic effects of NDRG1 in BC have been reported to relate to lipid metabolism or the mTOR signaling pathway. The molecular mechanism(s) of how NDRG1 regulates the activity of multiple signaling pathways remains unclear. Therapeutic strategies that up-regulate NDRG1 have been developed and include agents of the di-2-pyridylketone thiosemicarbazone class. These compounds target oncogenic drivers in BC cells, suppressing the expression of multiple key hormone receptors including ER-α, progesterone receptor, androgen receptor, and prolactin receptor, and can also overcome tamoxifen resistance. Considering the varying role of NDRG1 in BC pathogenesis, further studies are required to examine what subset of BC patients would benefit from pharmacopeia that up-regulate NDRG1.

Biomarkers and Treatment Strategies for Breast Cancer Recurrence

Despite recent treatment advancements, breast cancer remains a life-threatening disease. Although treatment is successful in the early stages, a significant proportion of individuals with breast cancer eventually experience a recurrence of the disease. Breast tumour recurrence poses a significant medical issue. Despite tumours being a primary cause of mortality, there remains a limited understanding of the fundamental mechanisms underlying tumour recurrence. The majority of the time, after surgery or medical treatment, this metastatic disease manifests itself after the disease is undiagnosed for a considerable amount of time. This phenomenon is commonly referred to as a relapse or recurrence. Metastatic breast cancer has the potential to recur at varying intervals, ranging from a few months to several decades following the initial diagnosis and treatment. This article aimed to summarise the primary causes of breast cancer recurrence and highlight the key issues that need to be addressed in order to effectively decrease the mortality rate among breast cancer patients. This article discusses various therapeutic approaches currently employed and emerging treatment strategies that hold the potential for the complete cure of cancer.

Regulation of Signaling from the Epidermal Growth Factor Family

The epidermal growth factor (EGF) system has allowed chemists, biologists, and clinicians to improve our understanding of cell production and cancer therapy. The discovery of EGF led to the recognition of cell surface receptors capable of controlling the proliferation and survival of cells. The detailed structures of the EGF-like ligand and the responses of their receptors (EGFR-family) has revealed the conformational and aggregation changes whereby ligands activate the intracellular kinase domains. Biophysical analysis has revealed the preformed clustering of different EGFR-family members and the processes which occur on ligand binding. Understanding these receptor activation processes and the consequential cytoplasmic signaling has allowed the development of inhibitors which are revolutionizing cancer therapy. This Review describes the recent progress in our understanding of the activation of the EGFR-family, the effects of signaling from the EGFR-family on cell proliferation, and the targeting of the EGFR-family in cancer treatment.

Current State of Cell Therapies for Breast Cancer

Metastatic breast cancer (BC) is an aggressive form of cancer and is an absolute challenge to treat. This review discusses the standard treatments available for metastatic BC. It further highlights the rationale for targeting oncodrivers, tumor-associated antigens, and neoantigens in BC. Explaining the significance of immune response in successful immunotherapeutic studies, it draws attention towards how adoptive cell therapy can be a useful immunotherapeutic tool. We focus on adoptive cell therapy in BC covering tumor-infiltrating lymphocyte therapy, engineered T cell receptor therapy, chimeric antigen receptor therapy, dendritic cell therapy and natural killer cell therapy. In this work, we aim to provide an overview of clinical data regarding the use of cellular immunotherapies in BC. Eventually, we conclude by proposing future adoptive cell therapy approaches, which can be used to cure BC.

DNA Hydroxymethylation in Smoking-Associated Cancers

5-hydroxymethylcytosine (5-hmC) was first detected in mammalian DNA five decades ago. However, it did not take center stage in the field of epigenetics until 2009, when ten-eleven translocation 1 (TET1) was found to oxidize 5-methylcytosine to 5-hmC, thus offering a long-awaited mechanism for active DNA demethylation. Since then, a remarkable body of research has implicated DNA hydroxymethylation in pluripotency, differentiation, neural system development, aging, and pathogenesis of numerous diseases, especially cancer. Here, we focus on DNA hydroxymethylation in smoking-associated carcinogenesis to highlight the diagnostic, therapeutic, and prognostic potentials of this epigenetic mark. We describe the significance of 5-hmC in DNA demethylation, the importance of substrates and cofactors in TET-mediated DNA hydroxymethylation, the regulation of TETs and related genes (isocitrate dehydrogenases, fumarate hydratase, and succinate dehydrogenase), the cell-type dependency and genomic distribution of 5-hmC, and the functional role of 5-hmC in the epigenetic regulation of transcription. We showcase examples of studies on three major smoking-associated cancers, including lung, bladder, and colorectal cancers, to summarize the current state of knowledge, outstanding questions, and future direction in the field.

The Yin and Yang of ERBB4: Tumor Suppressor and Oncoprotein

ERBB4 (HER4) is a member of the ERBB family of receptor tyrosine kinases, a family that includes the epidermal growth factor receptor (EGFR/ERBB1/HER1), ERBB2 (Neu/HER2), and ERBB3 (HER3). EGFR and ERBB2 are oncoproteins and validated targets for therapeutic intervention in a variety of solid tumors. In contrast, the role that ERBB4 plays in human malignancies is ambiguous. Thus, here we review the literature regarding ERBB4 function in human malignancies. We review the mechanisms of ERBB4 signaling with an emphasis on mechanisms of signaling specificity. In the context of this signaling specificity, we discuss the hypothesis that ERBB4 appears to function as a tumor suppressor protein and as an oncoprotein. Next, we review the literature that describes the role of ERBB4 in tumors of the bladder, liver, prostate, brain, colon, stomach, lung, bone, ovary, thyroid, hematopoietic tissues, pancreas, breast, skin, head, and neck. Whenever possible, we discuss the possibility that ERBB4 mutants function as biomarkers in these tumors. Finally, we discuss the potential roles of ERBB4 mutants in the staging of human tumors and how ERBB4 function may dictate the treatment of human tumors. SIGNIFICANCE STATEMENT: This articles reviews ERBB4 function in the context of the mechanistic model that ERBB4 homodimers function as tumor suppressors, whereas ERBB4-EGFR or ERBB4-ERBB2 heterodimers act as oncogenes. Thus, this review serves as a mechanistic framework for clinicians and scientists to consider the role of ERBB4 and ERBB4 mutants in staging and treating human tumors.

Multimodal Bone Metastasis-associated Epidermal Growth Factor Receptor Imaging in an Orthotopic Rat Model

Purpose To develop multimodality imaging techniques for measuring epidermal growth factor receptor (EGFR) as a therapy-relevant and metastasis-associated molecular marker in triple-negative mammary adenocarcinoma metastases. Materials and Methods An orthotopic bone metastasis EGFR-positive, triple-negative breast cancer (TNBC) model in rats was used for bioluminescence imaging, SPECT/CT, PET/CT, and MRI with quantitative analysis of transcripts (n = 22 rats). Receptor-specific MRI of EGFR expression in vivo was performed by acquiring spin-echo T1-weighted images after sequential administration of a pair of anti-EGFR antigen binding fragments, F(ab')₂, conjugated to either horseradish peroxidase or glucose oxidase, which have complementing activities, as well as paramagnetic (gadolinium[III]-mono-5-hydroxytryptamide of 2,2',2''-(10-(2,6-dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid, or Gd-5HT-DOTAGA) or positron-emitting (gallium 68-5HT-DOTAGA) substrates for MRI and PET/CT imaging, respectively. EGFR expression was confirmed by quantitative reverse transcriptase polymerase chain reaction and immunohistochemical analyses to compare with image findings. Results After surgical intraarterial delivery of TNBC cells, rats developed tumors that diverged into either rapidly growing osteolytic or slow-growing nonosteolytic tumors. Both tumor types showed receptor-specific initial MRI signal enhancement (contrast-to-noise ratio) that was three to six times higher than that of normal bone marrow (29.4 vs 4.9; P < .01). Micro PET/CT imaging of EGFR expression demonstrated a high level of heterogeneity with regional uptake of the tracer, which corresponded to region-of-interest MRI signal intensity elevation (121.1 vs 93.3; P < .001). Analysis of metastases with corroboration of imaging results showed high levels of EGFR protein and messenger RNA, or mRNA, expression in the invasive tumor. Conclusion Convergence of multimodal molecular receptor imaging enabled comprehensive assessment of EGFR overexpression in an orthotopic model of TNBC metastasis. Keywords: Animal Studies, Molecular Imaging-Cancer, MR-Contrast Agent, Radionuclide Studies, Skeletal-Appendicular, Metastases Supplemental material is available for this article. © RSNA, 2021.

Knockdown of AKT3 Activates HER2 and DDR Kinases in Bone-Seeking Breast Cancer Cells, Promotes Metastasis In Vivo and Attenuates the TGFβ/CTGF Axis

Bone metastases frequently occur in breast cancer patients and lack appropriate treatment options. Hence, understanding the molecular mechanisms involved in the multistep process of breast cancer bone metastasis and tumor-induced osteolysis is of paramount interest. The serine/threonine kinase AKT plays a crucial role in breast cancer bone metastasis but the effect of individual AKT isoforms remains unclear. Therefore, AKT isoform-specific knockdowns were generated on the bone-seeking MDA-MB-231 BO subline and the effect on proliferation, migration, invasion, and chemotaxis was analyzed by live-cell imaging. Kinome profiling and Western blot analysis of the TGFβ/CTGF axis were conducted and metastasis was evaluated by intracardiac inoculation of tumor cells into NOD scid gamma (NSG) mice. MDA-MB-231 BO cells exhibited an elevated AKT3 kinase activity in vitro and responded to combined treatment with AKT- and mTOR-inhibitors. Knockdown of AKT3 significantly increased migration, invasion, and chemotaxis in vitro and metastasis to bone but did not significantly enhance osteolysis. Furthermore, knockdown of AKT3 increased the activity and phosphorylation of pro-metastatic HER2 and DDR1/2 but lowered protein levels of CTGF after TGFβ-stimulation, an axis involved in tumor-induced osteolysis. We demonstrated that AKT3 plays a crucial role in bone-seeking breast cancer cells by promoting metastatic potential without facilitating tumor-induced osteolysis.

Molecular docking and molecular dynamic studies: screening of phytochemicals against EGFR, HER2, estrogen and NF-KB receptors for their potential use in breast cancer

Breast cancer (BC) is a second common malignancy in female globally. Hence, identification of novel therapeutic agents is extremely important. Molecular docking and MD simulation are the important tools in the process of drug discovery for searching the potential hits. The structure-based drug designing technique also reveals the information about ligands behavior in computational environment. Docking tools help in visualization and analysis of protein-ligand complex at atomic level. Molecular dynamics shows the stability of the molecules in the receptor cavity in the simulated environment. In this research work, we have screened potent phytochemicals against the BC. We docked the phytochemicals and examined the binding affinities of ligands towards the EGFR, HER2, estrogen and NF-κB receptors. Pristimerin, ixocarpalactone A, viscosalactone B and zhankuic acid A have shown higher binding affinities and energies towards targeted receptors among the screened phytochemicals. MD simulation study shows stability of docked complex for pristimerin and HER2 receptor. These phytochemicals can be repurposed for their anticancer activity. This in-silico work provides a strong ground for further investigation of their anticancer activity.

Review on Epidermal Growth Factor Receptor (EGFR) Structure, Signaling Pathways, Interactions, and Recent Updates of EGFR Inhibitors

The epidermal growth factor receptor (EGFR) belongs to the ERBB family of tyrosine kinase receptors. EGFR signaling cascade is a key regulator in cell proliferation, differentiation, division, survival, and cancer development. In this review, the EGFR structure and its mutations, signaling pathway, ligand binding and EGFR dimerization, EGF/EGFR interaction, and the progress in the development of EGFR inhibitors have been explored.

Kinome scale profiling of venom effects on cancer cells reveals potential new venom activities

The search for novel and relevant cancer therapeutics is continuous and ongoing. Cancer adaptations, resulting in therapeutic treatment failures, fuel this continuous necessity for new drugs to novel targets. Recently, researchers have started to investigate the effect of venoms and venom components on different types of cancer, investigating their mechanisms of action. Receptor tyrosine kinases (RTKs) comprise a family of highly conserved and functionally important druggable targets for cancer therapy. This research exploits the novelty of complex venom mixtures to affect phosphorylation of the epidermal growth factor receptor (EGFR) and related RTK family members, dually identifying new activities and unexplored avenues for future cancer and venom research. Six whole venoms from diverse species taxa, were evaluated for their ability to illicit changes in the phosphorylated expression of a panel of 49 commonly expressed RTKs. The triple negative breast cancer cell line MDA-MB-468 was treated with optimised venom doses, pre-determined by SDS PAGE and Western blot analysis. The phosphorylated expression levels of 49 RTKs in response to the venoms were assessed with the use of Human Phospho-RTK Arrays and analysed using ImageLab 5.2.1 analysis software (BioRad). Inhibition of EGFR phosphorylation occurred with treatment of venom from Acanthoscurria geniculata (Theraphosidae), Heterometrus swammerdami (Scorpionidae), Crotalus durissus vegrandis (Crotalidae) and Naja naja (Elapidae). Western green mamba Dendroaspis viridis venom increased EGFR phosphorylation. Eph, HGFR and HER were the most affected receptor families by venoms. Whilst the importance of these changes in terms of effect on MDA-MB-468 cells' long-term viability and functionality are still unclear, the findings present exciting opportunities for further investigation as potential drug targets in cancer and as tools to understand better how these pathways interact.

ΕGFR/ERβ-Mediated Cell Morphology and Invasion Capacity Are Associated with Matrix Culture Substrates in Breast Cancer

Breast cancer accounts for almost one in four cancer diagnoses in women. Studies in breast cancer patients have identified several molecular markers, indicators of aggressiveness, which help toward more individual therapeutic approaches. In triple-negative breast cancer (TNBC), epidermal growth factor receptor (EGFR) overexpression is associated with increased metastatic potential and worst survival rates. Specifically, abnormal EGFR activation leads to altered matrix metalloproteinases' (MMPs) expression and, hence, extracellular matrix (ECM) degradation, resulting in induced migration and invasion. The use of matrix substrates for cell culture gives the opportunity to mimic the natural growth conditions of the cells and their microenvironment, as well as cell-cell and cell-matrix interactions. The aim of this study was to evaluate the impact of EGFR inhibition, estrogen receptor beta (ERβ) and different matrix substrates [type I collagen and fibronectin (FN)] on the functional properties, expression of MMPs and cell morphology of ERβ-positive TNBC cells and shERβ ones. Our results highlight EGFR as a crucial regulator of the expression and activity levels of MMPs, while ERβ emerges as a mediator of MMP7 and MT1-MMP expression. In addition, the EGFR/ERβ axis impacts the adhesion and invasion potential of breast cancer cells on collagen type I. Images obtained by scanning electron microscope (SEM) from cultures on the different matrix substrates revealed novel observations regarding various structures of breast cancer cells (filopodia, extravesicles, tunneling nanotubes, etc.). Moreover, the significant contribution of EGFR and ERβ in the morphological characteristics of these cells is also demonstrated, hence highlighting the possibility of dual pharmacological targeting.

Developing a safe and effective CAR T-cell immunotherapy for breast cancer: progress and pitfalls

Current targeted therapies for breast cancer include hormone inhibitors, monoclonal antibodies and tyrosine kinase inhibitors. However, a significant unmet therapeutic need remains for refractory disease and in particular for the triple negative subtype, which lacks hormone receptors and HER2. Chimeric antigen receptors T cells are genetically engineered to deploy selective cytolytic activity against cells that express cognate native target. Durable remissions have been achieved in refractory hematological malignancies but similar success against solid tumors remains elusive. Several hurdles hinder progress, including the need to identify safe antigens, promote T-cell homing to tumor sites and to ensure the persistence of functional chimeric antigen receptors T cells within the immunosuppressive tumor microenvironment. Perspectives to enable the attainment of this goal are presented in this review.

The impact of EGFR gene polymorphisms on the response and toxicity derived from neoadjuvant chemotherapy for breast cancer

Background

Neoadjuvant chemotherapy is usually used for treating locally advanced breast cancer. However, not all patients achieve pathologic complete response (pCR). In this study, we selected two epidermal growth factor receptor (EGFR) single nucleotide polymorphism (SNP) sites, rs1468727 and rs845552, to investigate the association between the genotypes and the response and toxicity derived from neoadjuvant chemotherapy for breast cancer.

Methods

All participants took part in clinical trial SHPD001 and SHPD002. For univariate analyses, the association between SNP and pCR or toxicity was analyzed by Chi-square or Fisher's exact test. For multivariate analyses, logistic regression was used instead.

Results

In all, one hundred and eighteen patients were enrolled. We found that the frequency of AA genotype in rs845552 was higher than that of other genotypes in HER2-positive breast cancer (AA vs. AG, P=0.039; AA vs. GG, P=0.005; AA vs. AG+GG, P=0.009). Multivariate logistic regression analyses showed that pCR was more difficult to be achieved in patients with a CT genotype in rs1468727 compared to those with a CC+TT genotype (OR =0.288, 95% CI: 0.109-0.762, P=0.012) or a CC genotype (OR =0.254, 95% CI: 0.076-0.849, P=0.026). Moreover, we demonstrated that both rs1468727 and rs845552 were associated with toxicity that results in complications such as increased total bilirubin, skin rash, peripheral neuropathy, and alopecia (P<0.05).

Conclusions

Our study reported for the first time, that in treating breast cancer with neoadjuvant chemotherapy, EGFR SNP rs1468727 is associated with treatment response, and that both rs1468727 and rs845552 are related to treatment-derived toxicity. In addition, we also found that rs845552 may be related to the status of HER2 in breast cancer.

Biologically driven cut-off definition of lymphocyte ratios in metastatic breast cancer and association with exosomal subpopulations and prognosis

High neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR) are respectively associated with systemic inflammation and immune suppression and have been associated with a poor outcome. Plasmatic exosomes are extracellular vesicles involved in the intercellular communication system that can exert an immunosuppressive function. Aim of this study was to investigate the interplay between the immune system and circulating exosomes in metastatic breast cancer (MBC). A threshold capable to classify patients according to MLR, NLR and PLR, was computed through a receiving operator curve analysis after propensity score matching with a series of female blood donors. Exosomes were isolated from plasma by ExoQuick solution and characterized by flow-cytometry. NLR, MLR, PLR and exosomal subpopulations potentially involved in the pre-metastatic niche were significantly different in MBC patients with respect to controls. MLR was significantly associated with number of sites at the onset of metastatic disease, while high levels of MLR and NLR were found to be associated with poor prognosis. Furthermore, exosomal subpopulations varied according to NLR, MLR, PLR and both were associated with different breast cancer subtypes and sites of distant involvement. This study highlights the nuanced role of immunity in MBC spread, progression and outcome. Moreover, they suggest potential interaction mechanisms between immunity, MBC and the metastatic niche.

Fibroblast subtypes define a metastatic matrisome in breast cancer

Small primary breast cancers can show surprisingly high potential for metastasis. Clinical decision-making for tumor aggressiveness, including molecular profiling, relies primarily on analysis of the cancer cells. Here we show that this analysis is insufficient - that the stromal microenvironment of the primary tumor plays a key role in tumor cell dissemination and implantation at distant sites. We previously described 2 cancer-associated fibroblasts (CAFs) that either express (CD146+) or lack (CD146-) CD146 (official symbol MCAM, alias MUC18). We now find that when mixed with human breast cancer cells, each fibroblast subtype determines the fate of cancer cells: CD146- fibroblasts promoted increased metastasis compared with CD146+ fibroblasts. Potentially novel quantitative and qualitative proteomic analyses showed that CD146+ CAFs produced an environment rich in basement membrane proteins, while CD146- CAFs exhibited increases in fibronectin 1, lysyl oxidase, and tenascin C, all overexpressed in aggressive disease. We also show clinically that CD146- CAFs predicted for likelihood of lymph node involvement even in small primary tumors (<5 cm). Clearly small tumors enriched for CD146- CAFs require aggressive treatments.

The Central Contributions of Breast Cancer Stem Cells in Developing Resistance to Endocrine Therapy in Estrogen Receptor (ER)-Positive Breast Cancer

Breast cancer stem cells (BCSC) play critical roles in the acquisition of resistance to endocrine therapy in estrogen receptor (ER)-positive (ER + ve) breast cancer (BC). The resistance results from complex alterations involving ER, growth factor receptors, NOTCH, Wnt/β-catenin, hedgehog, YAP/TAZ, and the tumor microenvironment. These mechanisms are likely converged on regulating BCSCs, which then drive the development of endocrine therapy resistance. In this regard, hormone therapies enrich BCSCs in ER + ve BCs under both pre-clinical and clinical settings along with upregulation of the core components of “stemness” transcriptional factors including SOX2, NANOG, and OCT4. SOX2 initiates a set of reactions involving SOX9, Wnt, FXY3D, and Src tyrosine kinase; these reactions stimulate BCSCs and contribute to endocrine resistance. The central contributions of BCSCs to endocrine resistance regulated by complex mechanisms offer a unified strategy to counter the resistance. ER + ve BCs constitute approximately 75% of BCs to which hormone therapy is the major therapeutic approach. Likewise, resistance to endocrine therapy remains the major challenge in the management of patients with ER + ve BC. In this review we will discuss evidence supporting a central role of BCSCs in developing endocrine resistance and outline the strategy of targeting BCSCs to reduce hormone therapy resistance.

Androgen receptor promotes oral squamous cell carcinoma cell migration by increasing EGFR phosphorylation

Objectives: This study is aimed to investigate the role of androgen receptor (AR) in regulating oral squamous cell carcinoma (OSCC) cells migration.

Materials and methods: Tumors from 23 patients with OSCC and five OSCC cell lines were used for analyzing AR expression. The effects of AR agonist and antagonist were used to examine the role of AR in regulating the migration of OSCC cells.

Results: Ten of 23 tumors from patients with OSCC were AR positive. There was no significant difference in total EGFR (tEGFR) expression between AR-positive tumors and AR-negative tumors. However, the expression of phosphorylated EGFR (pEGFR) in AR-positive tumors was significantly higher than that in AR-negative tumors (p<0.01). Stimulation of AR by dihydrotestosterone in SCC9 (AR-positive OSCC cell) caused an increase in pEGFR and pAKT expression and promoted cell migration without changed tEGFR expression, whereas treatment with bicalutamide led to a decrement in pEGFR expression and pAKT and inhibited cell migration. No effects were found in SCC25 cell line (AR-negative) either treated by dihydrotestosterone or bicalutamide. Furthermore, SCC9 cell line treated by EGF or cetuximab (EGFR inhibitor) significantly promoted or inhibited cell migration.

Conclusion: Our data indicate that OSSC tumors and OSCC cell lines express AR which is critical for promoting cell migration by increasing EGFR phosphorylation.

Therapeutic Efficiency of an External Chinese Herbal Formula of Mammary Precancerous Lesions by BATMAN-TCM Online Bioinformatics Analysis Tool and Experimental Validation

Ruyan Neixiao Cream (RYNXC), a patented Chinese herbal formula, was reported to have the effect of treating mammary precancerous disease. In this study, we predicted the potential targets, pathways, and diseases of the ingredients contained in each herbal of RYNXC and constructed an ingredients-targets-diseases network. Then, we analyzed molecular mechanisms of this Chinese herbal formula by MCF-10AT cells and model rats of breast precancerous lesions. BATMAN-TCM prediction showed that ESR1, PGR, PTGS2, EGFR, and Src were mRNA targets of RYNXC. Our results suggested that RYNXC transdermal fluid downregulated ESR1, PGR, PTGS2, EGFR, and Src expression at gene and protein level in MCF-10AT cells. In the rat breast precancerous lesions model, high and low dose RYNXC could also significantly reduce genes and proteins expression of ESR1, PGR, PTGS2, EGFR, and Src. Taken together these data indicate that RYNXC targets multiple molecules responsible for breast precancerous lesion and is an effective Chinese herbal formula. So RYNXC may be a promising external drug for breast precancerous lesions.

Challenges and Opportunities from Basic Cancer Biology for Nanomedicine for Targeted Drug Delivery

Background:

Effective cancer therapy is still a great challenge for modern medical research due to the complex underlying mechanisms of tumorigenesis and tumor metastasis, and the limitations commonly associated with currently used cancer therapeutic options. Nanotechnology has been implemented in cancer therapeutics with immense potential for improving cancer treatment.

Objective:

Through information about the recent advances regarding cancer hallmarks, we could comprehensively understand the pharmacological effects and explore the mechanisms of the interaction between the nanomaterials, which could provide opportunities to develop mechanism-based nanomedicine to treat human cancers.

Methods:

We collected related information and data from articles.

Results:

In this review, we discussed the characteristics of cancer including tumor angiogenesis, abnormalities in tumor blood vessels, uncontrolled cell proliferation markers, multidrug resistance, tumor metastasis, cancer cell metabolism, and tumor immune system that provide opportunities and challenges for nanomedicine to be directed to specific cancer cells and portray the progress that has been accomplished in application of nanotechnology for cancer treatment.

Conclusion:

The information presented in this review can provide useful references for further studies on developing effective nanomedicine for the treatment of cancer.

The exosomal compartment protects epidermal growth factor receptor from small molecule inhibitors

Epidermal growth factor receptor (EGFR) plays a significant role in promoting breast cancer progression. However, targeting EGFR as a single treatment only resulted in moderate efficacy to the disease. The underlying mechanism of low responsiveness to EGFR inhibition remains largely unclear. Tumor-secreted extracellular vesicles (EVs) play a crucial role in mediating intercellular communication between tumor and stromal cells in local microenvironment and distant metastatic niche. Extracellular vesicles mediate cell-to-cell transfer of lipids, nucleic acids, and proteins. Although numerous recent studies have demonstrated exchanges of extracellular vesicles between cancer cells and the recipient cells contribute to tumor proliferation, invasion, and metastasis, yet little is known how the exosomal compartment responds to targeted therapies and their role in promoting drug resistance. In the current study we used a triple-negative breast cancer model to show that EV-encapsulated EGFR is protected from targeted inhibitors of EGFR and can trigger signaling pathway in recipient cancer cells, promoting proliferation and migration ability in vitro. Taken together, our study suggested a novel mechanism of drug resistance entailing the EV compartment, such as exosomes, as a target shelter which when released can signal for tumor promotion in the recipient cancer cells.

Med19 is targeted by miR-101-3p/miR-422a and promotes breast cancer progression by regulating the EGFR/MEK/ERK signaling pathway

Our previous study found that mediator complex subunit 19 (Med19) is upregulated and involved in breast cancer tumorigenesis; however, the detailed effects and mechanism of Med19 in breast cancer require further study. In this study, we found that Med19 was obviously elevated in human breast cancer tissues, which was significantly associated with larger tumors, high-grade malignant features and poor prognosis. Furthermore, Med19 enhanced breast cancer cell proliferation, epithelial-mesenchymal transition, invasion and migration in vitro and in vivo. Med19 interacted with epidermal growth factor receptor (EGFR) and increased EGFR expression. Moreover, Med19 activated the EGFR/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway and exerted its oncogenic activity in an EGFR signaling-mediated manner. In addition, Med19 expression was regulated by miR-101-3p and miR-422a. Med19 expression positively correlated with EGFR expression and negatively correlated with miR-101-3p and miR-422a expression in human breast cancer tissues. Med19 mediated the crosstalk between miR-101-3p/miR-422a and the EGFR/MEK/ERK signaling pathway. This study revealed a new miR-101-3p/miR-422a-Med19-EGFR/MEK/ERK axis that plays a significant role in breast cancer progression. These results help elucidate the potential mechanisms of Med19 in human breast cancer progression.

Posttranscriptional upregulation of HER3 by HER2 mRNA induces trastuzumab resistance in breast cancer

BACKGROUND

HER2 gene amplification generates an enormous number of HER2 transcripts, but the global effects on endogenous miRNA targets including HER family members in breast cancer are unexplored.

METHODS

We generated a HER2-3'UTR expressing vector to test the tumor-promoting properties in HER2 low expressing T47D and MCF7 cells. Through microarray analysis and real-time PCR analysis we identified genes that were regulated by HER2-3'UTR. Positive and negative manipulation of miRNA expression, response element mutational studies and transcript reporter assays were performed to explore the mechanism of competitive sequestration of miR125a/miRNA125b by HER2 3'UTR. To investigate if trastuzumab-induced upregulation of HER3 is also mediated through miRNA de-repression, we used the CRISPR/cas9 to mutate the endogenous HER2 mRNA in HER2 over-expressing Au565 cells. Finally, we looked at cohorts of breast cancer samples of our own and the TCGA to show if HER2 and HER3 mRNAs correlate with each other.

RESULTS

The HER2 3'UTR pronouncedly promoted cell proliferation, colony formation, and breast tumor growth. High-throughput sequencing revealed a significant increase in HER3 mRNA and protein levels by the HER2 3'untranslated region (3'UTR). The HER2 3'UTR harboring a shared miR-125a/b response element induced miR-125a/b sequestration and thus resulted in HER3 mRNA derepression. Trastuzumab treatment upregulated HER3 via elevated HER2 mRNA expression, leading to trastuzumab resistance. Depletion of miR-125a/b enhanced the antitumor activity of trastuzumab. Microarray data from HER2-overexpressing primary breast cancer showed significant elevation of mRNAs for predicted miR-125a/b targets compared to non-targets.

CONCLUSIONS

These results suggest that HER2 3'UTR-mediated HER3 upregulation is involved in breast cell transformation, increased tumor growth, and resistance to anti-HER2 therapy. The combinatorial targeting of HER3 mRNA or miR-125a/b may offer an effective tool for breast cancer therapy.

The Maxi-K (BK) Channel Antagonist Penitrem A as a Novel Breast Cancer-Targeted Therapeutic

Breast cancer (BC) is a heterogeneous disease with different molecular subtypes. The high conductance calcium-activated potassium channels (BK, Maxi-K channels) play an important role in the survival of some BC phenotypes, via membrane hyperpolarization and regulation of cell cycle. BK channels have been implicated in BC cell proliferation and invasion. Penitrems are indole diterpene alkaloids produced by various terrestrial and marine Penicillium species. Penitrem A (1) is a selective BK channel antagonist with reported antiproliferative and anti-invasive activities against multiple malignancies, including BC. This study reports the high expression of BK channel in different BC subtypes. In silico BK channel binding affinity correlates with the antiproliferative activities of selected penitrem analogs. 1 showed the best binding fitting at multiple BK channel crystal structures, targeting the calcium-sensing aspartic acid moieties at the calcium bowel and calcium binding sites. Further, 1 reduced the levels of BK channel expression and increased expression of TNF-&alpha; in different BC cell types. Penitrem A (1) induced G1 cell cycle arrest of BC cells, and induced upregulation of the arrest protein p27. Combination treatment of 1 with targeted anti-HER drugs resulted in synergistic antiproliferative activity, which was associated with reduced EGFR and HER2 receptor activation, as well as reduced active forms of AKT and STAT3. Collectively, the BK channel antagonists represented by penitrem A can be novel sensitizing, chemotherapeutics synergizing, and therapeutic agents for targeted BC therapy.

Calmodulin promotes matrix metalloproteinase 9 production and cell migration by inhibiting the ubiquitination and degradation of TBC1D3 oncoprotein in human breast cancer cells

The hominoid oncoprotein TBC1D3 enhances growth factor (GF) signaling and GF signaling, conversely, induces the ubiquitination and subsequent degradation of TBC1D3. However, little is known regarding the regulation of this degradation, and the role of TBC1D3 in the progression of tumors has also not been defined. In the present study, we demonstrated that calmodulin (CaM), a ubiquitous cellular calcium sensor, specifically interacted with TBC1D3 in a Ca²⁺-dependent manner and inhibited GF signaling-induced ubiquitination and degradation of the oncoprotein in both cytoplasm and nucleus of human breast cancer cells. The CaM-interacting site of TBC1D3 was mapped to amino acids 157~171, which comprises two 1–14 hydrophobic motifs and one lysine residue (K166). Deletion of these motifs was shown to abolish interaction between TBC1D3 and CaM. Surprisingly, this deletion mutation caused inability of GF signaling to induce the ubiquitination and subsequent degradation of TBC1D3. In agreement with this, we identified lysine residue 166 within the CaM-interacting motifs of TBC1D3 as the actual site for the GF signaling-induced ubiquitination using mutational analysis. Point mutation of this lysine residue exhibited the same effect on TBC1D3 as the deletion mutant, suggesting that CaM inhibits GF signaling-induced degradation of TBC1D3 by occluding its ubiquitination at K166. Notably, we found that TBC1D3 promoted the expression and activation of MMP-9 and the migration of MCF-7 cells. Furthermore, interaction with CaM considerably enhanced such effect of TBC1D3. Taken together, our work reveals a novel model by which CaM promotes cell migration through inhibiting the ubiquitination and degradation of TBC1D3.

The importance of EGFR as a biomarker in molecular apocrine breast cancer

Molecular apocrine breast cancer (MABC) is a molecular subtype with a poor prognosis, and there is urgent need to find new therapeutic targets. Epidermal growth factor receptor (EGFR) plays an important part in regulating the biological behavior of tumor cells, and EGFR-targeted drugs have already been used in therapy for lung and colorectal cancers. The purpose of this study was to analyze the significance of EGFR expression in MABC. A total of 400 patients with invasive breast cancer were analyzed, including 200 MABC and 200 non-MABC cases. Immunohistochemistry and immunofluorescence were carried out to evaluate the expression of estrogen receptor, progesterone receptor, androgen receptor (AR), EGFR, epidermal growth factor receptor 2 (HER2), and other biomarkers. Two hundred twelve (53%) cases were positive for EGFR expression, including 173 MABC and 39 non-MABC cases. EGFR expression was positively associated with AR expression in MABC, as well as with more advanced tumor stage and high Ki67 expression. Patients with EGFR expression had worse outcomes than those without. As a prognosis biomarker, EGFR was significantly associated with poorer clinical outcomes, and the co-expression of EGFR and HER2 often predicted worse outcomes in MABC. This study suggests that the identification of new targets such as HER2 and EGFR may help with assessing the prognosis of patients with MABC. Using both AR and EGFR as therapeutic targets may be especially important in MABC and may help to guide the choice of suitable treatments for individual breast cancer patients.

A combinational therapy of EGFR-CAR NK cells and oncolytic herpes simplex virus 1 for breast cancer brain metastases

Breast cancer brain metastases (BCBMs) are common in patients with metastatic breast cancer and indicate a poor prognosis. These tumors are especially resistant to currently available treatments due to multiple factors. However, the combination of chimeric antigen receptor (CAR)-modified immune cells and oncolytic herpes simplex virus (oHSV) has not yet been explored in this context. In this study, NK-92 cells and primary NK cells were engineered to express the second generation of EGFR-CAR. The efficacies of anti-BCBMs of EGFR-CAR NK cells, oHSV-1, and their combination were tested in vitro and in a breast cancer intracranial mouse model. In vitro, compared with mock-transduced NK-92 cells or primary NK cells, EGFR-CAR-engineered NK-92 cells and primary NK cells displayed enhanced cytotoxicity and IFN-γ production when co-cultured with breast cancer cell lines MDA-MB-231, MDA-MB-468, and MCF-7. oHSV-1 alone was also capable of lysing and destroying these cells. However, a higher cytolytic effect of EGFR-CAR NK-92 cells was observed when combined with oHSV-1 compared to the monotherapies. In the mice intracranially pre-inoculated with EGFR-expressing MDA-MB-231 cells, intratumoral administration of either EGFR-CAR-transduced NK-92 cells or oHSV-1 mitigated tumor growth. Notably, the combination of EGFR-CAR NK-92 cells with oHSV-1 resulted in more efficient killing of MDA-MB-231 tumor cells and significantly longer survival of tumor-bearing mice when compared to monotherapies. These results demonstrate that regional administration of EGFR-CAR NK-92 cells combined with oHSV-1 therapy is a potentially promising strategy to treat BCBMs.

Adoptive T-Cell Therapy for Solid Tumors

Chimeric antigen receptor (CAR) T-cell therapy is an innovative form of immunotherapy wherein autologous T cells are genetically modified to express chimeric receptors encoding an antigen-specific single-chain variable fragment and various costimulatory molecules. Upon administration, these modified T cells traffic to, and recognize, cancer cells in an HLA-independent manner. CAR T-cell therapy has shown remarkable success in the treatment of CD-19-expressing B-cell acute lymphocytic leukemia. However, clinical gains to the same magnitude have not been reported in solid tumors. Several known obstacles to CAR T-cell therapy for solid tumors include target antigen identification, effective trafficking to the tumor, robust activation, proliferation, and in vivo cytotoxicity. Beyond these T-cell intrinsic properties, a complex and dynamic immunosuppressive tumor microenvironment in solid tumors hinders T-cell efficacy. Notable advancements in CAR design to include multiple costimulatory molecules, ligands, and soluble cytokines have shown promise in preclinical models, and some of these are currently in early-phase clinical trials. In this review, we discuss selected solid tumor malignancies and relevant preclinical data and highlight clinical trial results that are available. Furthermore, we outline some obstacles to CAR T-cell therapy for each tumor and propose strategies to overcome some of these limitations.

Adoptive T-Cell Therapy for Solid Tumors

Chimeric antigen receptor (CAR) T-cell therapy is an innovative form of immunotherapy wherein autologous T cells are genetically modified to express chimeric receptors encoding an antigen-specific single-chain variable fragment and various costimulatory molecules. Upon administration, these modified T cells traffic to, and recognize, cancer cells in an HLA-independent manner. CAR T-cell therapy has shown remarkable success in the treatment of CD-19-expressing B-cell acute lymphocytic leukemia. However, clinical gains to the same magnitude have not been reported in solid tumors. Several known obstacles to CAR T-cell therapy for solid tumors include target antigen identification, effective trafficking to the tumor, robust activation, proliferation, and in vivo cytotoxicity. Beyond these T-cell intrinsic properties, a complex and dynamic immunosuppressive tumor microenvironment in solid tumors hinders T-cell efficacy. Notable advancements in CAR design to include multiple costimulatory molecules, ligands, and soluble cytokines have shown promise in preclinical models, and some of these are currently in early-phase clinical trials. In this review, we discuss selected solid tumor malignancies and relevant preclinical data and highlight clinical trial results that are available. Furthermore, we outline some obstacles to CAR T-cell therapy for each tumor and propose strategies to overcome some of these limitations.

POPDC1 is suppressed in human breast cancer tissues and is negatively regulated by EGFR in breast cancer cell lines

Breast cancer molecular heterogeneity has resulted in disparities in therapeutic response and targeting of molecular subtypes of breast cancer. This necessitates identification and validation of novel therapeutic targets for breast cancer treatment. Suppression of Popeye domain-containing (POPDC) proteins is hypothesized to promote malignant cell behaviour and poor clinical outcomes in various cancers. We aimed to determine whether POPDC proteins are suppressed in human ductal carcinoma tissues and if this correlates to clinical progression and Her2 status. We further assessed if the EGFR regulated POPDC1 in breast cancer. Here we show significant suppression of POPDC1 in malignant breast cancer tissues without correlation to clinical progression. Interestingly, POPDC2 and POPDC3 were highly expressed in malignant breast tissues. Furthermore, HER2+ status significantly correlated with high POPDC2 and POPDC3, but not POPDC1 expression. We further show for the first time that low POPDC1 correlates to high EGFR expression in breast cancer tissues and that EGFR negatively regulates POPDC1 expression in MCF7, MDA231 and SKBR3 breast cancer cells. Furthermore, overexpression of POPDC1 in MCF7, MDA231 and SKBR3 cells attenuated EGF-mediated cell migration and proliferation. These findings show that POPDC1 is suppressed in breast cancer and can potentially be targeted to inhibit EGFR-mediated cell migration and proliferation.

Characterization of CADD522, a small molecule that inhibits RUNX2-DNA binding and exhibits antitumor activity

The RUNX2 transcription factor promotes breast cancer growth and metastasis through interactions with a variety of cofactors that activate or repress target genes. Using a direct drug discovery approach we identified CADD522 as a small molecule that inhibits the DNA binding of the runt box domain protein, RUNX2. The current study defines the effect of CADD522 on breast cancer growth and metastasis, and addresses the mechanisms by which it exerts its anti-tumor activity.

CADD522 treatment resulted in significant growth inhibition, clonogenic survival, tumorsphere formation, and invasion of breast cancer cells. CADD522 negatively regulated transcription of RUNX2 target genes such as matrix metalloproteinase-13, vascular endothelial growth factor and glucose transporter-1, but upregulated RUNX2 expression by increasing RUNX2 stability. CADD522 reduced RUNX2-mediated increases in glucose uptake and decreased the level of CBF-β and RUNX2 phosphorylation at the S451 residue. These results suggest several potential mechanisms by which CADD522 exerts an inhibitory function on RUNX2-DNA binding; interference with RUNX2 for the DNA binding pocket, inhibition of glucose uptake leading to cell cycle arrest, down-regulation of CBF-β, and reduction of S451-RUNX2 phosphorylation.

The administration of CADD522 into MMTV-PyMT mice resulted in significant delay in tumor incidence and reduction in tumor burden. A significant decrease of tumor volume was also observed in a CADD522-treated human triple-negative breast cancer-patient derived xenograft model. CADD522 impaired the lung retention and outgrowth of breast cancer cells in vivo with no apparent toxicity to the mice. Therefore, by inhibiting RUNX2-DNA binding, CADD522 may represent a potential antitumor drug.

Tumor-Stroma Crosstalk in Bone Tissue: The Osteoclastogenic Potential of a Breast Cancer Cell Line in a Co-Culture System and the Role of EGFR Inhibition

Although bone metastases represent a major challenge in the natural history of breast cancer (BC), the complex interactions involved have hindered the development of robust in vitro models. The aim of this work is the development of a preclinical model of cancer and bone stromal cells to mimic the bone microenvironment. We studied the effects on osteoclastogenesis of BC cells and Mesenchymal stem cells (MSC) cultured alone or in combination. We also analyzed: (a) whether the blockade of the Epithelial Growth Factor Receptor (EGFR) pathway modified their influence on monocytes towards differentiation, and (b) the efficacy of bone-targeted therapy on osteoclasts. We evaluated the osteoclastogenesis modulation of human peripheral blood monocytes (PBMC) indirectly induced by the conditioned medium (CM) of the human BC cell line SCP2, cultured singly or with MSC. Osteoclastogenesis was evaluated by TRAP analysis. The effect of the EGFR blockade was assessed by treating the cells with gefitinib, and analyzed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western Blot (WB). We observed that SCP2 co-cultured with MSC increased the differentiation of PBMC. This effect was underpinned upon pre-treatment of the co-culture with gefitinib. Co-culture of SCP2 with MSC increased the expression of both the bone-related marker Receptor Activator of Nuclear Factor κB (RANK) and EGFR in BC cells. These upregulations were not affected by the EGFR blockade. The effects of the CM obtained by the cells treated with gefitinib in combination with the treatment of the preosteoclasts with the bone-targeted agents and everolimus enhanced the inhibition of the osteoclastogenesis. Finally, we developed a fully human co-culture system of BC cells and bone progenitor cells. We observed that the interaction of MSC with cancer cells induced in the latter molecular changes and a higher power of inducing osteoclastogenesis. We found that blocking EGFR signaling could be an efficacious strategy for breaking the interactions between cancer and bone cells in order to inhibit bone metastasis.

The roles of subcellularly located EGFR in autophagy

The epidermal growth factor receptor (EGFR) is a well-studied receptor-tyrosine kinase that serves vital roles in regulation of organ development and cancer progression. EGFR not only exists on the plasma membrane, but also widely expressed in the nucleus, endosomes, and mitochondria. Most recently, several lines of evidences indicated that autophagy is regulated by EGFR in kinase-active and -independent manners. In this review, we summarized recent advances in our understanding of the functions of different subcellularly located EGFR on autophagy. Specifically, plasma membrane- and cytoplasm-located EGFR (pcEGFR) acts as a tyrosine kinase to regulate autophagy via the PI3K/AKT1/mTOR, RAS/MAPK1/3, and STAT3 signaling pathways. The kinase-independent function of pcEGFR inhibits autophagy by maintaining SLC5A1-regulated intracellular glucose level. Endosome-located EGFR phosphorylates and inhibits Beclin1 to suppress autophagy, while kinase-independent endosome-located EGFR releases Beclin1 from the Rubicon-Beclin1 complex to increase autophagy. Additionally, the nuclear EGFR activates PRKDC/PNPase/MYC signaling to inhibit autophagy. Although the role of mitochondria-located EGFR in autophagy is largely unexplored, the production of ATP and reactive oxygen species mediated by mitochondrial dynamics is most likely to influence autophagy.

Exploring the pharmacological mechanism of Yanghe Decoction on HER2-positive breast cancer by a network pharmacology approach

ETHNOPHARMACOLOGICAL RELEVANCE

Certain Chinese medicine formulae from traditional Chinese Medicine (TCM) are effective for treating and preventing diseases in clinical practice. Yanghe Decoction (YHD) is a Chinese medicine formula that is used to treat breast cancer, especially HER-positive breast cancer; however, the active compounds, potential targets, and pharmacological and molecular mechanism of its action against cancer remain unclear. Therefore, further investigation is required.

METHODS

A network pharmacology approach comprising drug-likeness evaluation, oral bioavailability prediction, Caco-2 permeability prediction, multiple compound target prediction, multiple know target collection, breast cancer genes collection, and network analysis has been used in this study.

RESULTS

Four networks are set up, including HER2-positive breast cancer network, compound-compound target network of YHD, YHD-HER2-positive breast cancer network and compound-known target-HER2-positive breast cancer network, and some HER2-positive breast cancer and YHD related targets, clusters, biological processes and pathways are found. We also found some potential anti-cancer compounds.

CONCLUSION

Our works successfully predict, illuminate and confirm the molecular synergy of YHD for HER2-positive breast cancer and found the potential HER2-positive breast cancer associated targets, cluster, biological processes and pathways. This study not only provide clues to the researcher who explores pharmacological and molecular mechanism of YHD acting on HER2-positive breast cancer, but also demonstrates a feasible method for discovering potential drugs from Chinese medicine formulae.

Ridle for sparse regression with mandatory covariates with application to the genetic assessment of histologic grades of breast cancer

Background

Many questions in statistical genomics can be formulated in terms of variable selection of candidate biological factors for modeling a trait or quantity of interest. Often, in these applications, additional covariates describing clinical, demographical or experimental effects must be included a priori as mandatory covariates while allowing the selection of a large number of candidate or optional variables. As genomic studies routinely require mandatory covariates, it is of interest to propose principled methods of variable selection that can incorporate mandatory covariates.

Methods

In this article, we propose the ridge-lasso hybrid estimator (ridle), a new penalized regression method that simultaneously estimates coefficients of mandatory covariates while allowing selection for others. The ridle provides a principled approach to mitigate effects of multicollinearity among the mandatory covariates and possible dependency between mandatory and optional variables. We provide detailed empirical and theoretical studies to evaluate our method. In addition, we develop an efficient algorithm for the ridle. Software, based on efficient Fortran code with R-language wrappers, is publicly and freely available at https://sites.google.com/site/zhongyindaye/software.

Results

The ridle is useful when mandatory predictors are known to be significant due to prior knowledge or must be kept for additional analysis. Both theoretical and comprehensive simulation studies have shown that the ridle to be advantageous when mandatory covariates are correlated with the irrelevant optional predictors or are highly correlated among themselves. A microarray gene expression analysis of the histologic grades of breast cancer has identified 24 genes, in which 2 genes are selected only by the ridle among current methods and found to be associated with tumor grade.

Conclusions

In this article, we proposed the ridle as a principled sparse regression method for the selection of optional variables while incorporating mandatory ones. Results suggest that the ridle is advantageous when mandatory covariates are correlated with the irrelevant optional predictors or are highly correlated among themselves.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0291-y) contains supplementary material, which is available to authorized users.