Cross-talk between the ErbB/HER family and the type I insulin-like growth factor receptor signaling pathway in breast cancer

Targeting Receptor Tyrosine Kinases as a Novel Strategy for the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) comprises a group of aggressive and heterogeneous breast carcinoma. Chemotherapy is the mainstay for the treatment of triple-negative tumors. Nevertheless, the success of chemotherapeutic treatments is limited by their toxicity and development of acquired resistance leading to therapeutic failure and tumor relapse. Hence, there is an urgent need to explore novel targeted therapies for TNBC. Receptor tyrosine kinases (RTKs) are a family of transmembrane receptors that are key regulators of intracellular signaling pathways controlling cell proliferation, differentiation, survival, and motility. Aberrant activity and/or expression of several types of RTKs have been strongly connected to tumorigenesis. RTKs are frequently overexpressed and/or deregulated in triple-negative breast tumors and are further associated with tumor progression and reduced survival in patients. Therefore, targeting RTKs could be an appealing therapeutic strategy for the treatment of TNBC. This review summarizes the current evidence regarding the antitumor activity of RTK inhibitors in preclinical models of TNBC. The review also provides insights into the clinical trials evaluating the use of RTK inhibitors for the treatment of patients with TNBC.

Novel N-(3-ethynyl Phenyl)-6,7-bis(2-methoxyethoxy)Quinazoline-4-amine Derivatives: Synthesis, Characterization, Anti-cancer Activity, In-silico and DFT Studies

BACKGROUND

Cancer is one of the most common reasons for mortality in the world. A continuous effort to develop effective anti-cancer drugs with minimum side effects has become necessary. The use of small-molecule drugs has revolutionized cancer research by inhibiting cancer cell survival and proliferation. Quinazolines are a class of bioactive heterocyclic compounds with active pharmacophores in several anti-cancer drugs. Such small molecule inhibitors obstruct the significant signals responsible for cancer cell development, thus blocking these cell signals to prevent cancer development and spread.

OBJECTIVE

In the current study, novel quinazoline derivatives structurally similar to erlotinib were synthesized and explored as novel anti-cancer agents.

METHODS

All the synthesized molecules were confirmed by spectroscopic techniques like 1H NMR, 13C NMR, and ESI-MS. Various techniques were applied to study the protein-drug interaction, DFT analysis, Hirshfeld surface, and target prediction. The molecules were screened in vitro for their anti-cancer properties against 60 human tumor cell lines. The growth inhibitory properties of a few compounds were studied against the MCF7 breast cancer cell line.

RESULTS

The activity of compounds 9f, 9o, and 9s were found to be active. However, compound 9f is more active when compared with other compounds.

CONCLUSION

Some synthesized compounds were active against different cancer cell lines. The in-vitro study results were found to be in agreement with the predictions from in-silico data. The selected molecules were further subjected to get the possible mechanism of action against different cancer cells.

Signaling Pathways of the Insulin-like Growth Factor Binding Proteins

The 6 high-affinity insulin-like growth factor binding proteins (IGFBPs) are multifunctional proteins that modulate cell signaling through multiple pathways. Their canonical function at the cellular level is to impede access of insulin-like growth factor (IGF)-1 and IGF-2 to their principal receptor IGF1R, but IGFBPs can also inhibit, or sometimes enhance, IGF1R signaling either through their own post-translational modifications, such as phosphorylation or limited proteolysis, or by their interactions with other regulatory proteins. Beyond the regulation of IGF1R activity, IGFBPs have been shown to modulate cell survival, migration, metabolism, and other functions through mechanisms that do not appear to involve the IGF-IGF1R system. This is achieved by interacting directly or functionally with integrins, transforming growth factor β family receptors, and other cell-surface proteins as well as intracellular ligands that are intermediates in a wide range of pathways. Within the nucleus, IGFBPs can regulate the diverse range of functions of class II nuclear hormone receptors and have roles in both cell senescence and DNA damage repair by the nonhomologous end-joining pathway, thus potentially modifying the efficacy of certain cancer therapeutics. They also modulate some immune functions and may have a role in autoimmune conditions such as rheumatoid arthritis. IGFBPs have been proposed as attractive therapeutic targets, but their ubiquity in the circulation and at the cellular level raises many challenges. By understanding the diversity of regulatory pathways with which IGFBPs interact, there may still be therapeutic opportunities based on modulation of IGFBP-dependent signaling.

Metformin and HER2-positive breast cancer: Mechanisms and therapeutic implications

Due to the strong association between diabetes and cancer incidents, several anti-diabetic drugs, including metformin, have been examined for their anticancer activity. Metformin is a biguanide antihyperglycemic agent used as a first-line drug for type II diabetes mellitus. It exhibits anticancer activity by impacting different molecular pathways, such as AMP-inducible protein kinase (AMPK)-dependent and AMPK-independent pathways. Additionally, Metformin indirectly inhibits IGF-1R signaling, which is highly activated in breast malignancy. On the other hand, breast cancer is one of the major causes of cancer-related morbidity and mortality worldwide, where the human epidermal growth factor receptor-positive (HER2-positive) subtype is one of the most aggressive ones with a high rate of lymph node metastasis. In this review, we summarize the association between diabetes and human cancer, listing recent evidence of metformin's anticancer activity. A special focus is dedicated to HER2-positive breast cancer with regards to the interaction between HER2 and IGF-1R. Then, we discuss combination therapy strategies of metformin and other anti-diabetic drugs in HER2-positive breast cancer.

Human epidermal growth factor receptor 2 (HER2)-specific chimeric antigen receptor (CAR) for tumor immunotherapy; recent progress

Due to the overexpression or amplification of human epidermal growth factor receptor 2 (HER2) with poor prognosis in a myriad of human tumors, recent studies have focused on HER2-targeted therapies. Deregulation in HER2 signaling pathways is accompanied by sustained tumor cells growth concomitant with their migration and also tumor angiogenesis and metastasis by stimulation of proliferation of a network of blood vessels. A large number of studies have provided clear evidence that the emerging HER2-directed treatments could be the outcome of patients suffering from HER2 positive breast and also gastric/gastroesophageal cancers. Thanks to its great anti-tumor competence, immunotherapy using HER2-specific chimeric antigen receptor (CAR) expressing immune cell has recently attracted increasing attention. Human T cells and also natural killer (NK) cells can largely be found in the tumor microenvironment, mainly contributing to the tumor immune surveillance. Such properties make them perfect candidate for genetically modification to express constructed CARs. Herein, we will describe the potential targets of the HER2 signaling in tumor cells to clarify HER2-mediated tumorigenesis and also discuss recent findings respecting the HER2-specific CAR-expressing immune cells (CAR T and CAR NK cell) for the treatment of HER2-expressing tumors.

Progress in the Research and Targeted Therapy of ErbB/HER Receptors in Urothelial Bladder Cancer

Bladder cancer is a lethal malignancy and a majority of bladder cancer arise from urothelial cells. Infiltration and metastasis are barriers for the radical cystectomy to achieve favored outcome and are the main cause of death. Systemic therapy, including chemotherapy, targeted therapy, and immunotherapy, is fundamental for these patients. erbB/HER receptors are found to be overexpressed in a subgroup of urothelial carcinoma, targeting erbB/HER receptors in these patients was found to be an efficient way in the era of genetic testing. To evaluate the role of erbB/HER receptors in bladder cancer, we reviewed the literature and ongoing clinical trials as regards to this topic to unveil the context of erbB/HER receptors in bladder cancer, which probably help to solidate the theoretical basis and might instruct further research.

Biological effects and regulation of IGFBP5 in breast cancer

The insulin-like growth factor receptor (IGF1R) pathway plays an important role in cancer progression. In breast cancer, the IGF1R pathway is linked to estrogen-dependent signaling. Regulation of IGF1R activity is complex and involves the actions of its ligands IGF1 and IGF2 and those of IGF-binding proteins (IGFBPs). Six IGFBPs are known that share the ability to form complexes with the IGFs, by which they control the bioavailability of these ligands. Besides, each of the IGFBPs have specific features. In this review, the focus lies on the biological effects and regulation of IGFBP5 in breast cancer. In breast cancer, estrogen is a critical regulator of IGFBP5 transcription. It exerts its effect through an intergenic enhancer loop that is part of the chromosomal breast cancer susceptibility region 2q35. The biological effects of IGFBP5 depend upon the cellular context. By inhibiting or promoting IGF1R signaling, IGFBP5 can either act as a tumor suppressor or promoter. Additionally, IGFBP5 possesses IGF-independent activities, which contribute to the complexity by which IGFBP5 interferes with cancer cell behavior.

Identification of Candidate Genes in Early-Stage Invasive Ductal Carcinoma Patients with High-Risk Mortality Using Genes Commonly Involved in Breast Cancer: A Retrospective Study

INTRODUCTION

Invasive ductal carcinoma (IDC) of the breast is a heterogeneous disease characterized by multiple subtypes. IDC survival is highly impacted by tumor burden, molecular subtypes, and gene profiles. Gene mutation is a type of genomic instability regarded as having a considerable effect on IDC prognosis. Using integrated survival analysis, this study identified candidate genes and a high-risk group of patients with early-stage IDC to provide further understanding of the genetic characteristics associated with poor survival.

METHODS

The gene mutation profiles, baseline demographics, clinicopathologic variables, and treatment characteristics of the early-stage IDC subpopulation were downloaded from an open access data platform. These data were analyzed for a total of 444 patients. In total, 40 genes commonly involved in IDC were listed, and the genes exhibiting significant differences (as estimated using the log-rank test) were selected as the candidate genes.

RESULTS

The patients were divided into control, low-risk, and high-risk groups according to their gene mutation profiles. The 5-year overall survival rates of low-risk, control, and high-risk patients were 97.4%, 96.1%, and 73.0%, respectively. The high-risk group had a significantly higher risk of poor overall -survival (adjusted hazard ratio = 6.57, 95% confidence interval = 1.51-28.7, p = 0.012) than that of the control group, and the low-risk group did not have a significant survival difference compared with control group.

CONCLUSIONS

This study proposed an integrative approach for the identification of candidate genes for risk assessment of overall survival in these patients through typical survival analysis methods. The 14 candidate genes selected are particularly involved in cell-cycle processes, deoxyribonucleic acid repair, and drug resistance; their mutations were found to be generally associated with disease progression or therapeutic resistance, which is commonly associated with poor overall survival outcomes in IDC.

Circulating ERBB3 levels are inversely associated with the risk of overweight-related hypertension: a cross-sectional study

BACKGROUND

Hypertension and overweight are independent risk factors for cardiovascular disease, and overweight increase the risk of developing high blood pressure. ERBB3( also known as HER3) plays a considerable role in the development of cardiovascular diseases. However, the effect of ERBB3 levels in hypertensive overweight patients is unknown. The aim of this study was to assess the association between ERBB3 levels and hypertension in overweight Chinese patients.

METHODS

We evaluated the height,weight, blood pressure, biochemical indicators, and ERBB3 levels in 128 Chinese adults aged 33-79 years. Plasma ERBB3 levels were assessed by the enzyme-linked immunosorbent assay, and body mass index(BMI) was calculated as body weight divided by height squared. Participants were allocated into three groups according to blood pressure and BMI: healthy control (CNT, n = 31; normotensive and non-overweight), hypertension (HT, n = 33; hypertension and non-overweight), and hypertension with overweight (HTO, n = 64; hypertension and overweight). Statistical significance was defined as a two-tailed P < 0.05.

RESULTS

There was no significant difference in mean ERBB3 levels among the three groups, although a linear decrease from CNT (1.13 ± 0.36), HT (1.03 ± 0.36), to HTO (0.84 ± 0.26 ng/mL) was observed in men (P = 0.007). Among the drinking population, the ERBB3 level was significantly reduced in the HTO group as compared with those of the CNT and HT groups (0.76 ± 0.23 versus 1.18 ± 0.37 and 1.20 ± 0.30, respectively). ERBB3 levels were negatively correlated with diastolic blood pressure in men (r= - 0.293, P = 0.012), smoking (r= - 0.47, P = 0.004), and drinking (r = - 0.387, P = 0.008). BMI in men and among drinkers, and uric acid among drinkers were negatively correlated with ERBB3 levels. Multivariate conditional logistic regression showed that plasma ERBB3 levels were associated with a reduced risk of HTO in men [odds ratio (OR) 0.054; 95 % confidence interval (CI): 0.007-0.412) and drinkers (OR 0.002; 95 % CI: 0.000-0.101).

CONCLUSIONS

ERBB3 may contribute to the pathogenesis of hypertension in overweight patients, with BMI, gender, and drinking all potentially modulating the process.

Dual Inhibition of AKT and MEK Pathways Potentiates the Anti-Cancer Effect of Gefitinib in Triple-Negative Breast Cancer Cells

There is an unmet medical need for the development of new targeted therapeutic strategies for triple-negative breast cancer (TNBC). With drug combination screenings, we found that the triple combination of the protein kinase inhibitors (PKIs) of the epidermal growth factor receptor (EGFR), v-akt murine thymoma viral oncogene homolog (AKT), and MAPK/ERK kinase (MEK) is effective in inducing apoptosis in TNBC cells. A set of PKIs were first screened in combination with gefitinib in the TNBC cell line, MDA-MB-231. The AKT inhibitor, AT7867, was identified and further analyzed in two mesenchymal stem-like (MSL) subtype TNBC cells, MDA-MB-231 and HS578T. A combination of gefitinib and AT7867 reduced the proliferation and long-term survival of MSL TNBC cells. However, gefitinib and AT7867 induced the activation of the rat sarcoma (RAS)/ v-raf-1 murine leukemia viral oncogene homolog (RAF)/MEK/ extracellular signal-regulated kinase (ERK) pathway. To inhibit this pathway, MEK/ERK inhibitors were further screened in MDA-MB-231 cells in the presence of gefitinib and AT7867. As a result, we identified that the MEK inhibitor, PD-0325901, further enhanced the anti-proliferative and anti-clonogenic effects of gefitinib and AT7867 by inducing apoptosis. Our results suggest that the dual inhibition of the AKT and MEK pathways is a novel potential therapeutic strategy for targeting EGFR in TNBC cells.

Tumor-associated neutrophils as new players in immunosuppressive process of the tumor microenvironment in breast cancer

Despite the conventional reputation of neutrophils to have antibacterial properties, recent studies have put emphasis and are interested in the role of neutrophils in the spread and treatment of cancer. It has been shown that the infiltration of neutrophils, either by exerting pro- or anti-tumoral effects, probably affects tumor prognosis. Tumor-associated neutrophils (TANs) probably participate in tumor promotion and development in different ways, such as increasing genomic instability, induction of immunosuppression, and increasing angiogenesis. Despite major advances in breast cancer treatment, it is the second leading cause of death in American women. It has been revealed that inflammation is a fundamental issue in the treatment of this cancer because tumor growth, invasion, metastasis, and vascularization can be affected by inflammatory factors. It is demonstrated that enhanced neutrophil to lymphocyte ratio probably contributes to the raised rate of mortality and decreased survival among breast cancer cases. The present review explores the biology of TANs, their suspected interactions in the breast cancer microenvironment, and their functions in preserving the tumor microenvironment and progression of tumors. Furthermore, their potential as therapeutic targets and clinical biomarkers has been discussed in this paper.

MicroRNA-423 Drug Resistance and Proliferation of Breast Cancer Cells by Targeting ZFP36

BACKGROUND/AIMS

The effects of microRNA-423 on proliferation and drug resistance of breast cancer cells were explored, the downstream target genes of miR-423 and the targeted regulatory relationship between them were studied.

METHODS

RT-qPCR was used to detect the expression of miR-423 in breast cancer tissues and cell lines, and the transfection efficiency of miR-423 inhibitory vector miR-423-inhibitor was constructed and verified. CCK-8 and colony formation assays were used to examine the effect of miR-423 on tumor cell proliferation. Target gene prediction and screening and luciferase reporter assay were used to verify downstream target genes of miR-432. The mRNA and protein expression of miR-423target gene ZFP36 was detected by RT-qPCR and Western blotting.

RESULTS

The expression of miR-423 was significantly higher than that in normal tissues. Compared to the non-malignant mammary epithelial cell line MCF-10A, the expression of miR-423 was significantly raised in MCR-7 and MCF-7/ADR cells. ZFP36 was a downstream target gene of miR-423 and negatively correlated with the expression of miR-423 in breast cancer. The knockdown of miR-423 can significantly enhance the cytotoxicity of the drug, increase the apoptotic rate of MCF-7/ADR cells. miR-423 was capable of activating the Wnt/β-catenin signaling pathway leading to chemoresistance and proliferation, whereas overexpression of ZFP36 reduced drug resistance and proliferation.

CONCLUSION

miR-423 acted as an oncogene to promote tumor cell proliferation and migration. ZFP36 was a downstream target gene of miR-423, and miR-423 inhibited the expression of ZFP36 via Wnt/β-catenin signaling pathway of breast cancer cells.

Molecular Targeting Therapy against EGFR Family in Breast Cancer: Progress and Future Potentials

The epidermal growth factor receptor (EGFR) family contains four transmembrane tyrosine kinases (EGFR1/ErbB1, Her2/ErbB2, Her3/ErbB3 and Her4/ErbB4) and 13 secreted polypeptide ligands. EGFRs are overexpressed in many solid tumors, including breast, pancreas, head-and-neck, prostate, ovarian, renal, colon, and non-small-cell lung cancer. Such overexpression produces strong stimulation of downstream signaling pathways, which induce cell growth, cell differentiation, cell cycle progression, angiogenesis, cell motility and blocking of apoptosis.The high expression and/or functional activation of EGFRs correlates with the pathogenesis and progression of several cancers, which make them attractive targets for both diagnosis and therapy. Several approaches have been developed to target these receptors and/or the EGFR modulated effects in cancer cells. Most approaches include the development of anti-EGFRs antibodies and/or small-molecule EGFR inhibitors. This review presents the state-of-the-art and future prospects of targeting EGFRs to treat breast cancer.

In Vitro Investigation Demonstrates IGFR/VEGFR Receptor Cross Talk and Potential of Combined Inhibition in Pediatric Central Nervous System Atypical Teratoid Rhabdoid Tumors

BACKGROUND

Atypical teratoid rhabdoid tumor of the central nervous system (CNS ATRT) is a malignancy that commonly affects young children. The biological mechanisms contributing to tumor aggressiveness and resistance to conventional therapies in ATRT are unknown. Previous studies have shown the activity of insulin like growth factor-I receptor (IGF-1R) in ATRT tumor specimens and cell lines. IGF-1R has been shown to cross-talk with other receptor tyrosine kinases (RTKs) in a number of cancer types, leading to enhanced cell proliferation.

OBJECTIVE

This study aims to evaluate the role of IGF-1 receptor cross-talk in ATRT biology and the potential for therapeutic targeting.

METHODS

Cell lines derived from CNS ATRT specimens were analyzed for IGF-1 mediated cell proliferation. A comprehensive receptor tyrosine kinase (RTK) screen was conducted following IGF-1 stimulation. Bioinformatic analysis of publicly available cancer growth inhibition data to identify correlation between IC50 of a VEGFR inhibitor and IGF-1R expression.

RESULTS

Comprehensive RTK screen identified VEGFR-2 cross-activation following IGF-1 stimulation. Bioinformatics analysis demonstrated a positive correlation between IC50 values of VEGFR inhibitor Axitinib and IGF-1R expression, supporting the critical influence of IGF-1R in modulating response to anti-angiogenic therapies.

CONCLUSION

Overall, our data present a novel experimental framework to evaluate and utilize receptor cross-talk mechanisms to select effective drugs and combinations for future therapeutic trials in ATRT.

Single-Chain Variable Fragment-Based Bispecific Antibodies: Hitting Two Targets with One Sophisticated Arrow

Despite the success of monoclonal antibodies (mAbs) to treat some disorders, the monospecific molecular entity of mAbs as well as the presence of multiple factors and pathways involved in the pathogenesis of disorders, such as various malignancies, infectious diseases, and autoimmune disorders, and resistance to therapy have restricted the therapeutic efficacy of mAbs in clinical use. Bispecific antibodies (bsAbs), by concurrently recognizing two targets, can partly circumvent these problems. Serial killing of tumor cells by bsAb-redirected T cells, simultaneous blocking of two antigens involved in the HIV-1 infection, and concurrent targeting of the activating and inhibitory receptors on B cells to modulate autoimmunity are part of the capabilities of bsAbs. After designing and developing a large number of bsAbs for years, catumaxomab, a full-length bsAb targeting EpCAM and CD3, was approved in 2009 to treat EpCAM-positive carcinomas besides blinatumomab, a bispecific T cell engager antibody targeting CD19 and CD3, which was approved in 2014 to treat relapsed or refractory acute lymphoblastic leukemia. Furthermore, approximately 60 bsAbs are under investigation in clinical trials. The current review aims at portraying different formats of the single-chain variable fragment (scFv)-based bsAbs and shedding light on the scFv-based bsAbs in preclinical development, different phases of clinical trials, and the market.

Identification of Novel Breast Cancer Genes based on Gene Expression Profiles and PPI Data

Background:

Breast cancer is one of the most common malignancies, and a threat to female health all over the world. However, the molecular mechanism of breast cancer has not been fully discovered yet.

Objective:

It is crucial to identify breast cancer-related genes, which could provide new biomarker for breast cancer diagnosis as well as potential treatment targets.

Methods:

Here we used the minimum redundancy-maximum relevance (mRMR) method to select significant genes, then mapped the transcripts of the genes on the Protein-Protein Interaction (PPI) network and traced the shortest path between each pair of two proteins.

Results:

As a result, we identified 24 breast cancer-related genes whose betweenness were over 700. The GO enrichment analysis indicated that the transcription and oxygen level are very important in breast cancer. And the pathway analysis indicated that most of these 24 genes are enriched in prostate cancer, endocrine resistance, and pathways in cancer.

Conclusion:

We hope these 24 genes might be useful for diagnosis, prognosis and treatment for breast cancer.

The RTK Interactome: Overview and Perspective on RTK Heterointeractions

Receptor tyrosine kinases (RTKs) play important roles in cell growth, motility, differentiation, and survival. These single-pass membrane proteins are grouped into subfamilies based on the similarity of their extracellular domains. They are generally thought to be activated by ligand binding, which promotes homodimerization and then autophosphorylation in trans. However, RTK interactions are more complicated, as RTKs can interact in the absence of ligand and heterodimerize within and across subfamilies. Here, we review the known cross-subfamily RTK heterointeractions and their possible biological implications, as well as the methodologies which have been used to study them. Moreover, we demonstrate how thermodynamic models can be used to study RTKs and to explain many of the complicated biological effects which have been described in the literature. Finally, we discuss the concept of the RTK interactome: a putative, extensive network of interactions between the RTKs. This RTK interactome can produce unique signaling outputs; can amplify, inhibit, and modify signaling; and can allow for signaling backups. The existence of the RTK interactome could provide an explanation for the irreproducibility of experimental data from different studies and for the failure of some RTK inhibitors to produce the desired therapeutic effects. We argue that a deeper knowledge of RTK interactome thermodynamics can lead to a better understanding of fundamental RTK signaling processes in health and disease. We further argue that there is a need for quantitative, thermodynamic studies that probe the strengths of the interactions between RTKs and their ligands and between different RTKs.

Hyperinsulinemia Promotes Esophageal Cancer Development in a Surgically-Induced Duodeno-Esophageal Reflux Murine Model

Hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion, Barrett's Esophagus, a possible consequence of Gastro-Esophageal Reflux Disease. Obesity is known to mediate esophageal carcinogenesis through different mechanisms including insulin-resistance leading to hyperinsulinemia, which may mediate cancer progression via the insulin/insulin-like growth factor axis. We used the hyperinsulinemic non-obese FVB/N (Friend leukemia virus B strain) MKR (muscle (M)-IGF1R-lysine (K)-arginine (R) mouse model to evaluate the exclusive role of hyperinsulinemia in the pathogenesis of EAC related to duodeno-esophageal reflux. FVB/N wild-type (WT) and MKR mice underwent jejunum-esophageal anastomosis side-to end with the exclusion of the stomach. Thirty weeks after surgery, the esophagus was processed for histological, immunological and insulin/Insulin-like growth factor 1 (IGF1) signal transduction analyses. Most of the WT mice (63.1%) developed dysplasia, whereas most of the MKR mice (74.3%) developed squamous cell and adenosquamous carcinomas, both expressing Human Epidermal growth factor receptor 2 (HER2). Hyperinsulinemia significantly increased esophageal cancer incidence in the presence of duodenal-reflux. Insulin receptor (IR) and IGF1 receptor (IGF1R) were overexpressed in the hyperinsulinemic condition. IGF1R, through ERK1/2 mitogenic pattern activation, seems to be involved in cancer onset. Hyperinsulinemia-induced IGF1R and HER2 up-regulation could also increase the possibility of forming of IGF1R/HER2 heterodimers to support cell growth/proliferation/progression in esophageal carcinogenesis.

Immunization with HER2 extracellular subdomain proteins induces cellular response and tumor growth inhibition in mice

AIM

We investigated cellular and protective immune responses in mice vaccinated with recombinant HER2 extracellular subdomains.

MATERIALS & METHODS

Balb/C mice were immunized with recombinant full HER2 extracellular domain and subdomain proteins. Humoral and cellular immune response and antitumor effect was evaluated using a syngeneic mice tumor model.

RESULTS

All recombinant proteins induced secretion of IL-4 and particularly IFN-γ and IL-17 cytokines. Challenging of immunized mice with stable 4T1-HER2 transfected cells resulted in partial but significant tumor growth inhibition in all groups of mice particularly those immunized with fHER2-ECD together with CPG.

CONCLUSION

Our results suggest that the recombinant HER2-ECD subdomains induce mainly Th1 and Th17 responses, which seem to contribute to tumor growth inhibition in syngeneic mice.

Inhibition of PI3K/Akt/mTOR overcomes cisplatin resistance in the triple negative breast cancer cell line HCC38

Background

Widely established targeted therapies directed at triple negative breast cancer (TNBC) are missing. Classical chemotherapy remains the systemic treatment option. Cisplatin has been tested in TNBC but bears the disadvantage of resistance development. The purpose of this study was to identify resistance mechanisms in cisplatin-resistant TNBC cell lines and select targeted therapies based on these findings.

Methods

The TNBC cell lines HCC38 and MDA-MB231 were subjected to intermittent cisplatin treatment resulting in the 3.5-fold cisplatin-resistant subclone HCC38CisR and the 2.1-fold more resistant MDA-MB231CisR. Activation of pro-survival pathways was explored by immunostaining of phospho-receptor tyrosine kinases. Targeted therapies (NVP-AEW541, lapatinib and NVP-BEZ235) against activated pathways were investigated regarding cancer cell growth and cisplatin sensitivity.

Results

In HCC38CisR and MDA-MB231CisR, phosphorylation of epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF1R) was observed. In HCC38CisR, treatment with NVP-AEW541 increased potency of lapatinib almost seven-fold, but both compounds could not restore cisplatin sensitivity. However, the dual phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor NVP-BEZ235 acted synergistically with cisplatin in HCC38CisR and fully restored cisplatin sensitivity. Similarly, NVP-BEZ235 increased cisplatin potency in MDA-MB231CisR. Furthermore, NVP-AEW541 in combination with lapatinib restored cisplatin sensitivity in MDA-MB231CisR.

Conclusion

Simultaneous inhibition of EGFR and IGF1R in cisplatin-resistant TNBC cell lines was synergistic regarding inhibition of proliferation and induction of apoptosis. Co-treatment with NVP-BEZ235 or with a combination of NVP-AEW541 and lapatinib restored cisplatin sensitivity and may constitute a targeted treatment option for cisplatin-resistant TNBC.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3695-5) contains supplementary material, which is available to authorized users.

Predicting ligand-dependent tumors from multi-dimensional signaling features

Targeted therapies have shown significant patient benefit in about 5-10% of solid tumors that are addicted to a single oncogene. Here, we explore the idea of ligand addiction as a driver of tumor growth. High ligand levels in tumors have been shown to be associated with impaired patient survival, but targeted therapies have not yet shown great benefit in unselected patient populations. Using an approach of applying Bagged Decision Trees (BDT) to high-dimensional signaling features derived from a computational model, we can predict ligand dependent proliferation across a set of 58 cell lines. This mechanistic, multi-pathway model that features receptor heterodimerization, was trained on seven cancer cell lines and can predict signaling across two independent cell lines by adjusting only the receptor expression levels for each cell line. Interestingly, for patient samples the predicted tumor growth response correlates with high growth factor expression in the tumor microenvironment, which argues for a co-evolution of both factors in vivo.

Insulin promotes HER2 signaling activation during Barrett's Esophagus carcinogenesis

BACKGROUND

Insulin-resistance and hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion Barrett's Esophagus (BE). HER2 activation has also a pivotal role in EAC carcinogenesis but no data correlate these two phenomena in this disease context.

AIMS

To investigate the role of hyperinsulinemia in BE-dysplasia-adenocarcinoma sequence and the possible relationship between insulin-mediated and HER2 signaling in EAC development.

METHODS

Serum insulin, C-peptide, IGF1, glucagon, IL-6, TNF-alpha, leptin, adiponectin and Insulin-Resistance-index were analyzed in 19 patients with gastro-esophageal reflux disease, 51 with BE, 24 with dysplastic-BE and 14 with EAC. Insulin/IGF1/HER2 pathways were analyzed in esophageal biopsies using Luminex® Technology. Insulin effect was also evaluated in EAC-derived OE19 cells. Data were analyzed by Fisher's exact test, Kruskal-Wallis test, Mann-Whitney U-test, Cuzick's test and Spearman correlation coefficient calculation.

RESULTS

Insulin-Resistance-index, insulin and C-peptide levels increased along with disease progression (p=0.019, p=0.002, p<0.0001, respectively) and correlated with HER2 expression and with downstream mediators phospho-Akt and phospho-mTOR in esophageal tissue. In vitro, insulin was also able to induce cell proliferation through HER2 activation.

CONCLUSIONS

Our data pinpoint a possible role of hyperinsulinemia in the Barrett's Esophagus metaplasia-dysplasia-adenocarcinoma sequence through HER2 activation in esophageal epithelial cells.

IGF1R Protein Expression Is Not Associated with Differential Benefit to Concurrent Trastuzumab in Early-Stage HER2+ Breast Cancer from the North Central Cancer Treatment Group (Alliance) Adjuvant Trastuzumab Trial N9831

Background: Preclinical evidence indicates that increased insulin-like growth factor receptor-1 (IGF1R) signaling interferes with the action of trastuzumab suggesting a possible mechanism of trastuzumab resistance. Thus, we evaluated IGF1R prevalence, relationship with demographic data, and association with disease-free survival (DFS) of patients randomized to chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C) in the prospective phase III HER2⁺ adjuvant N9831 trial.Experimental Design: IGF1R protein expression was determined in tissue microarray sections (three cores per block; N = 1,197) or in whole tissue sections (WS; N = 537) using IHC (rabbit polyclonal antibody against IGF1R β-subunit). A tumor was considered positive (IGF1R⁺) if any core or WS had ≥1+ membrane staining in >0% invasive cells. Median follow-up was 8.5 years.Results: Of 1,734 patients, 708 (41%) had IGF1R⁺ breast tumors. IGF1R⁺ was associated with younger age (median 48 vs. 51, P = 0.007), estrogen receptor/progesterone receptor positivity (78% vs. 35%, P < 0.001), nodal positivity (89% vs. 83%, P < 0.001), well/intermediate grade (34% vs. 24%, P < 0.001), tumors ≥2 cm (72% vs. 67%, P = 0.02) but not associated with race or tumor histology. IGF1R did not affect DFS within arms. Between Arms A and C, patients with IGF1R⁺ and IGF1R^- tumors had DFS HRs of 0.48 (P ≤ 0.001) and 0.68 (P = 0.009), respectively (P_interaction = 0.17). Between Arms A and B, patients with IGF1R⁺ and IGF1R^- tumors had DFS HRs of 0.83 (P = 0.25) and 0.69 (P = 0.01), respectively (P_interaction = 0.42).Conclusions: In contrast to preclinical studies that suggest a decrease in trastuzumab sensitivity in IGF1R⁺ tumors, our adjuvant data show benefit of adding trastuzumab for patients with either IGF1R⁺ and IGF1R^- breast tumors. Clin Cancer Res; 23(15); 4203-11. ©2016 AACR.

ErbB Proteins as Molecular Target of Dietary Phytochemicals in Malignant Diseases

ErbB proteins overexpression, in both normal and mutated forms, is associated with invasive forms of cancer prone to metastasis and with stronger antiapoptotic mechanisms and therefore more challenging to treat. Downstream effectors of ErbB receptors mediating these phenotypic traits include MAPK, STAT, and PI3K/AKT/mTOR pathways. Various phytochemical compounds were studied for their large number of biological effects including anticancer activity. Among these compounds, epigallocatechin-3-gallate (EGCG), the main catechin from green tea leaves, and curcumin, component of the curry powder, constituted the object of numerous studies. Both compounds were shown to act directly either on ErbB expression, or on their downstream signaling molecules. In this paper we aim to review the involvement of ErbB proteins in cancer as well as the biologic activity of EGCG and curcumin in ErbB expressing and overexpressing malignancies. The problems arising in the administration of the two compounds due to their reduced bioavailability when orally administered, as well as the progress made in this field, from using novel formulations to improved dosing regimens or improved synthetic analogs, are also discussed.

Involvement of microRNAs in HER2 signaling and trastuzumab treatment

The prognostic value of HER2 has been demonstrated in many human cancer types such us breast cancer, gastric cancer and ovarian cancer. Trastuzumab is the first anti-HER2 monoclonal antibody that has remarkably improved outcomes of patients with HER2-positive breast cancer. For HER2-positive metastatic gastric cancers, the addition of trastuzumab to traditional chemotherapy also significantly prolonged overall survival. However, intrinsic and acquired resistance to trastuzumab is common and results in disease progression. HER2 signaling network and mechanisms underlying the resistance have been broadly investigated in order to develop strategy to overcome the dilemma. Increasing evidence indicates that microRNAs (miRNA), a group of small non-coding RNAs, are involved in HER2 signaling and trastuzumab treatment. This review summarizes all the miRNAs that target HER2 and describes their activity on biological processes. Moreover, miRNAs that regulate trastuzumab resistance and relevant molecular mechanisms are highlighted. MiRNA signatures associated with HER2, miRNAs that mediate trastuzumab activity, and potential miRNA biomarkers of trastuzumab sensitivity are also discussed.

3D pharmacophore-based virtual screening, docking and density functional theory approach towards the discovery of novel human epidermal growth factor receptor-2 (HER2) inhibitors

Human epidermal growth factor receptor 2 (HER2) is one of the four members of the epidermal growth factor receptor (EGFR) family and is expressed to facilitate cellular proliferation across various tissue types. Therapies targeting HER2, which is a transmembrane glycoprotein with tyrosine kinase activity, offer promising prospects especially in breast and gastric/gastroesophageal cancer patients. Persistence of both primary and acquired resistance to various routine drugs/antibodies is a disappointing outcome in the treatment of many HER2 positive cancer patients and is a challenge that requires formulation of new and improved strategies to overcome the same. Identification of novel HER2 inhibitors with improved therapeutics index was performed with a highly correlating (r=0.975) ligand-based pharmacophore model (Hypo1) in this study. Hypo1 was generated from a training set of 22 compounds with HER2 inhibitory activity and this well-validated hypothesis was subsequently used as a 3D query to screen compounds in a total of four databases of which two were natural product databases. Further, these compounds were analyzed for compliance with Veber's drug-likeness rule and optimum ADMET parameters. The selected compounds were then subjected to molecular docking and Density Functional Theory (DFT) analysis to discern their molecular interactions at the active site of HER2. The findings thus presented would be an important starting point towards the development of novel HER2 inhibitors using well-validated computational techniques.

Primary breast cancer cell culture yields intra-tumor heterogeneous subpopulations expressing exclusive patterns of receptor tyrosine kinases

Background

It has become evident that intra-tumor heterogeneity of breast cancer impact on several biological processes such as proliferation, migration, cell death and also might contribute to chemotherapy resistance. The expression of Receptor Tyrosine Kinases (RTKs) has not been analyzed in the context of intra-tumor heterogeneity in a primary breast cancer cell culture. Several subpopulations were isolated from the MBCDF (M serial-breast cancer ductal F line) primary breast cancer cells and were successfully maintained in culture and divided in two groups according to their morphology and RTKs expression pattern, and correlated with biological processes like proliferation, migration, anchorage-independent cell growth, and resistance to cytotoxic chemotherapy drugs and tyrosine kinase inhibitors (TKIs).

Methods

Subpopulations were isolated from MBCDF primary breast cancer cell culture by limiting dilution. RTKs and hormone receptors were examined by Western blot. Proliferation was measure by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT assay). Cell viability was evaluated by Crystal Violet. Migration was assessed using Boyden chambers. Anchorage-independent cell growth was evaluated by colony formation in soft agar.

Results

Several subpopulations were isolated from the MBCDF breast cancer cells that were divided into two groups according to their morphology. Analysis of RTKs expression pattern showed that HER1, HER3, c-Met and VEGFR2 were expressed exclusively in cells from group 1, but not in cells from group 2. PDGFR was expressed only in cells from group 2, but not in cells from group 1. HER2, HER4, c-Kit, IGF1-R were expressed in all subpopulations. Biological processes correlated with the RTKs expression pattern. Group 2 subpopulations present the highest rate of cell proliferation, migration and anchorage-independent cell growth. Analysis of susceptibility to chemotherapy drugs and TKIs showed that only Paclitaxel and Imatinib behaved differently between groups. Group 1-cells were resistant to both Paclitaxel and Imatinib.

Conclusions

We demonstrated that subpopulations from MBCDF primary cell culture could be divided into two groups according to their morphology and a RTKs excluding-expression pattern. The differences observed in RTKs expression correlate with the biological characteristics and chemoresistance of each group. These results suggest that intra-tumor heterogeneity contributes to generate groups of subpopulations with a more aggressive phenotype within the tumor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2769-0) contains supplementary material, which is available to authorized users.

Insulin activates EGFR by stimulating its interaction with IGF-1R in low-EGFR-expressing TNBC cells

The expression of epidermal growth factor receptor (EGFR) is an important diagnostic marker for triple-negative breast cancer (TNBC) cells, which lack three hormonal receptors: estrogen and progesterone receptors as well as epidermal growth factor receptor 2. EGFR transactivation can cause drug resistance in many cancers including TNBC, but the mechanism underlying this phenomenon is poorly defined. Here, we demonstrate that insulin treatment induces EGFR activation by stimulating the interaction of EGFR with insulin-like growth factor receptor 1 (IGF-1R) in the MDA-MB-436 TNBC cell line. These cells express low levels of EGFR, while exhibiting high levels of IGF-1R expression and phosphorylation. Low-EGFRexpressing MDA-MB-436 cells show high sensitivity to insulinstimulated cell growth. Therefore, unexpectedly, insulin stimulation induced EGFR transactivation by regulating its interaction with IGF-1R in low-EGFR-expressing TNBC cells.

Whole-transcriptome analysis of mouse adipose tissue in response to short-term caloric restriction

Caloric restriction (CR) has been shown to extend the lifespan of many species by improving cellular function and organismal health. Additionally, fat reduction by CR may play an important role in lengthening lifespan and preventing severe age-related diseases. Interestingly, CR induced the greatest transcriptome change in the epididymal fat of mice in our study. In this transcriptome analysis, we identified and categorized 446 genes that correlated with CR level. We observed down-regulation of several signaling pathways, including insulin/insulin-like growth factor 1 (insulin/IGF-1), epidermal growth factor (EGF), transforming growth factor beta (TGF-β), and canonical wingless-type mouse mammary tumor virus integration site (Wnt). Many genes related to structural features, including extracellular matrix structure, cell adhesion, and the cytoskeleton, were down-regulated, with a strong correlation to the degree of CR. Furthermore, genes related to the cell cycle and adipogenesis were down-regulated. These biological processes are well-identified targets of insulin/IGF-1, EGF, TGF-β, and Wnt signaling. In contrast, genes involved in specific metabolic processes, including the tricarboxylic acid cycle and the electron transport chain were up-regulated. We performed in silico analysis of the promoter sequences of CR-responsive genes and identified two associated transcription factors, Paired-like homeodomain 2 (Pitx2) and Paired box gene 6 (Pax6). Our results suggest that strict regulation of signaling pathways is critical for creating the optimal energy homeostasis to extend lifespan.

A paradigm shift: Cancer therapy with peptide-based B-cell epitopes and peptide immunotherapeutics targeting multiple solid tumor types: Emerging concepts and validation of combination immunotherapy

There is a recognizable and urgent need to speed the development and application of novel, more efficacious anti-cancer vaccine therapies that inhibit tumor progression and prevent acquisition of tumor resistance. We have created and established a portfolio of validated peptide epitopes against multiple receptor tyrosine kinases and we have identified the most biologically effective combinations of EGFR (HER-1), HER-2, HER-3, VEGF and IGF-1R peptide vaccines/mimics to selectively inhibit multiple receptors and signaling pathways. The strategy is based on the use of chimeric conformational B-cell epitope peptides incorporating "promiscuous" T-cell epitopes that afford the possibility of generating an enduring immune response, eliciting protein-reactive high-affinity anti-peptide antibodies as potential vaccines and peptide mimics that act as antagonists to receptor signaling that drive cancer metastasis. In this review we will summarize our ongoing studies based on the development of combinatorial immunotherapeutic strategies that act synergistically to enhance immune-mediated tumor killing aimed at addressing mechanisms of tumor resistance for several tumor types.

Mechanisms of action of therapeutic antibodies for cancer

The therapeutic utility of antibodies and their derivatives is achieved by various means. The FDA has approved several targeted antibodies that disrupt signaling of various growth factor receptors for the treatment of a number of cancers. Rituximab, and other anti-CD20 monoclonal antibodies are active in B cell malignancies. As more experience has been gained with anti-CD20 monoclonal antibodies, the multifactorial nature of their anti-tumor mechanisms has emerged. Other targeted antibodies function to dampen inhibitory checkpoints. These checkpoint inhibitors have recently achieved dramatic results in several cancers, including melanoma. These and related antibodies continue to be investigated in the clinical and pre-clinical settings. Novel antibody structures that target two or more antigens have also made their way into clinical use. Tumor targeted antibodies can also be conjugated to chemo- or radiotherapeutic agents, or catalytic toxins, as a means to deliver toxic payloads to cancer cells. Here we provide a review of these mechanisms and a discussion of their relevance to current and future clinical applications.

A probabilistic approach for automated discovery of perturbed genes using expression data from microarray or RNA-Seq

BACKGROUND

In complex diseases, alterations of multiple molecular and cellular components in response to perturbations are indicative of disease physiology. While expression level of genes from high-throughput analysis can vary among patients, the common path among disease progression suggests that the underlying cellular sub-processes involving associated genes follow similar fates. Motivated by the interconnected nature of sub-processes, we have developed an automated methodology that combines ideas from biological networks, statistical models, and game theory, to probe connected cellular processes. The core concept in our approach uses probability of change (POC) to indicate the probability that a gene's expression level has changed between two conditions. POC facilitates the definition of change at the neighborhood, pathway, and network levels and enables evaluation of the influence of diseases on the expression. The 'connected' disease-related genes (DRG) identified display coherent and concomitant differential expression levels along paths.

RESULTS

RNA-Seq and microarray breast cancer subtyping expression data sets were used to identify DRG between subtypes. A machine-learning algorithm was trained for subtype discrimination using the DRG, and the training yielded a set of biomarkers. The discriminative power of the biomarkers was tested using an unseen data set. Biomarkers identified overlaps with disease-specific identified genes, and we were able to classify disease subtypes with 100% and 80% agreement with PAM50, for microarray and RNA-Seq data set respectively.

CONCLUSIONS

We present an automated probabilistic approach that offers unbiased and reproducible results, thus complementing existing methods in DRG and biomarker discovery for complex diseases.

Dual inhibition of EGFR and MET induces synthetic lethality in triple-negative breast cancer cells through downregulation of ribosomal protein S6

Triple-negative breast cancer (TNBC) exhibits innate resistance to the EGFR inhibition despite high level expression of EGFR. Recently, we found that the proliferation of basal-like (BL) subtype TNBC cells is synergistically inhibited by combination of EGFR and PI3K/AKT inhibitors. On the contrary, TNBC cells of mesenchymal stem-like (MSL) subtype are resistant to these combinations. To identify potential synthetic lethal interaction of compounds for treatment of MSL subtype TNBC cells, we performed MTT screening of MDA-MB-231 cells with a small library of receptor tyrosine kinase inhibitors (RTKIs) in the presence of gefitinib, an EGFR inhibitor. We identified MET inhibitors as potent RTKIs that caused synthetic lethality in combination with gefitinib in MDA-MB-231 cells. We demonstrated that combination of a MET inhibitor SU11274 with various EGFR inhibitors resulted in synergistic suppression of cell viability (in MTT assay) and cell survival (in colony formation assay) of MSL subtype TNBC cells. We further demonstrated that SU11274 alone induced G2 arrest and gefitinib/SU11274 combination sustained the SU11274-induced G2 arrest in these cells. In addition, SU11274/gefitinib combination synergistically reduced the level of ribosomal protein S6 (RPS6) in MSL subtype TNBC cells. In addition, knockdown of RPS6 itself, in both HS578T and MDA-MB-231, markedly reduced the proliferation of these cells. Taken together, our data suggest that dual targeting of EGFR and MET inhibits the proliferation of MSL subtype TNBC cells through down-regulation of RPS6.

(-)-Liriopein B Suppresses Breast Cancer Progression via Inhibition of Multiple Kinases

Numerous breast cancer patients who achieve an initial response to HER-targeted therapy rapidly develop resistance within one year, leading to treatment failure. Observations from clinical samples indicate that such resistance correlates with an increase in Src, EGFR, and PI3K/Akt activities and a decrease in PTEN activity. Furthermore, Akt survival signaling activation is also found in tumors treated by toxic chemotherapeutic agents. Because cotreatment with a PI3K inhibitor is a promising strategy to delay acquired resistance by preventing secondary gene activation, we therefore investigated the effects of a newly identified compound, (-)-Liriopein B (LB), on PI3K/Akt signaling activity in breast cancer cells. Our results showed that nontoxic doses of LB are able to inhibit AKT activation in both luminal-like MCF-7 and basal-like MDA-MB-231 breast cancer cells. Low doses of LB also inhibited cell migration, invasion, and cancer-stem cell sphere formation. Suppression of EGF-induced EGFR and ERK1/2 activation by LB might contribute in part to retardation of cancer progression. Furthermore, LB increases sensitivity of MDA-MB-231 cells to gefitinib in vitro, suggesting that EGFR may not be the only target of LB. Finally, a small scale in vitro kinase assay screen demonstrated that LB has a potent inhibitory effect on multiple kinases, including PI3K, Src, EGFR, Tie2, lck, lyn, RTK5, FGFR1, Abl, and Flt. In conclusion, this study demonstrates for the first time that the compound LB improves tumor therapeutic efficacy and suggests LB as a promising candidate for studying new leads in the development of kinase inhibitors.

IGF-1R peptide vaccines/mimics inhibit the growth of BxPC3 and JIMT-1 cancer cells and exhibit synergistic antitumor effects with HER-1 and HER-2 peptides

The insulin-like growth factor-1 receptor (IGF-1R) plays a crucial role in cellular growth, proliferation, transformation, and inhibition of apoptosis. A myriad of human cancer types have been shown to overexpress IGF-1R, including breast and pancreatic adenocarcinoma. IGF-1R signaling interferes with numerous receptor pathways, rendering tumor cells resistant to chemotherapy, anti-hormonal therapy, and epidermal growth factor receptor (EGFR, also known as HER-1) and v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2, (ERBB2, best known as HER-2) -targeted therapies. Targeting the IGF:IGF-1R axis with innovative peptide inhibitors and vaccine antibodies thus represents a promising therapeutic strategy to overcome drug resistance and to provide new avenues for individualized and combinatorial treatment strategies. In this study, we designed, synthesized, and characterized several B-cell epitopes from the IGF-1:IGF-1R axis. The chimeric peptide epitopes were highly immunogenic in outbred rabbits, eliciting high levels of peptide vaccine antibodies. The IGF-1R peptide antibodies and peptide mimics inhibited cell proliferation and receptor phosphorylation, induced apoptosis and antibody-dependent cellular cytotoxicity (ADCC), and significantly inhibited tumor growth in the transplantable BxPC-3 pancreatic and JIMT-1 breast cancer models. Our results showed that the peptides and antibodies targeting residues 56-81 and 233-251 are potential therapeutic and vaccine candidates for the treatment of IGF-1R-expressing cancers, including those that are resistant to the HER-2-targeted antibody, trastuzumab. Additionally, we found additive antitumor effects for the combination treatment of the IGF-1R 56-81 epitope with HER-1-418 and HER-2-597 epitopes. Treatment with the IGF-1R/HER-1 or IGF-1R/HER-2 combination inhibited proliferation, invasion, and receptor phosphorylation, and induced apoptosis and ADCC, to a greater degree than single agents.

HER-3 peptide vaccines/mimics: Combined therapy with IGF-1R, HER-2, and HER-1 peptides induces synergistic antitumor effects against breast and pancreatic cancer cells

The human epidermal growth factor receptor 3 (HER-3/ErbB3) is a unique member of the human epidermal growth factor family of receptors, because it lacks intrinsic kinase activity and ability to heterodimerize with other members. HER-3 is frequently upregulated in cancers with epidermal growth factor receptor (EGFR/HER-1/ErbB1) or human epidermal growth factor receptor 2 (HER-2/ErBB2) overexpression, and targeting HER-3 may provide a route for overcoming resistance to agents that target EGFR or HER-2. We have previously developed vaccines and peptide mimics for HER-1, HER-2 and vascular endothelial growth factor (VEGF). In this study, we extend our studies by identifying and evaluating novel HER-3 peptide epitopes encompassing residues 99-122, 140-162, 237-269 and 461-479 of the HER-3 extracellular domain as putative B-cell epitopes for active immunotherapy against HER-3 positive cancers. We show that the HER-3 vaccine antibodies and HER-3 peptide mimics induced antitumor responses: inhibition of cancer cell proliferation, inhibition of receptor phosphorylation, induction of apoptosis and antibody dependent cellular cytotoxicity (ADCC). Two of the HER-3 epitopes 237-269 (domain II) and 461-479 (domain III) significantly inhibited growth of xenografts originating from both pancreatic (BxPC3) and breast (JIMT-1) cancers. Combined therapy of HER-3 (461-471) epitope with HER-2 (266-296), HER-2 (597-626), HER-1 (418-435) and insulin-like growth factor receptor type I (IGF-1R) (56-81) vaccine antibodies and peptide mimics show enhanced antitumor effects in breast and pancreatic cancer cells. This study establishes the hypothesis that combination immunotherapy targeting different signal transduction pathways can provide effective antitumor immunity and long-term control of HER-1 and HER-2 overexpressing cancers.

Inhibition of EGFR or IGF-1R signaling enhances radiation response in head and neck cancer models but concurrent inhibition has no added benefit

Interaction between the epidermal growth factor receptor (EGFR) and the insulin-like growth factor receptor (IGF-1R) has been well established in many cancer types. We investigated the effects of cetuximab (EGFR antibody) and IMC-A12 (IGF-1R antibody) on the response of head and neck squamous cell carcinoma (HNSCC) to radiation therapy (RT). The effects of cetuximab and IMC-A12 on cell viability and radiosensitivity were determined by clonogenic cell survival assay. Formation of nuclear γ-H2AX and 53BP1 foci was monitored by immunofluorescence. Alterations in target signaling were analyzed by Western blots. In vivo tumor growth delay assay was performed to determine the efficacy of triple therapy with IMC-A12, cetuximab, and RT. In vitro data showed that cetuximab differentially affected the survival and the radiosensitivity of HNSCC cells. Cetuximab suppressed DNA repair that was evident by the prolonged presence of nuclear γ-H2AX and 53BP1 foci. IMC-A12 did not have any effect on the cell survival. However, it increased the radiosensitivity of one of the cell lines. EGFR inhibition increased IGF-1R expression levels and also the association between EGFR and IGF-1R. Addition of IMC-A12 to cetuximab did not increase the radiosensitivity of these cells. Tumor xenografts exhibited enhanced response to RT in the presence of either cetuximab or IMC-A12. Concurrent treatment regimen failed to further enhance the tumor response to cetuximab and/or RT. Taken together our data suggest that concomitant inhibition of both EGFR and IGF-1R pathways did not yield additional therapeutic benefit in overcoming resistance to RT.

Functional genetic approach identifies MET, HER3, IGF1R, INSR pathways as determinants of lapatinib unresponsiveness in HER2-positive gastric cancer

PURPOSE

Targeting human epidermal growth factor receptor 2 (HER2) therapy is currently considered as the standard treatment for HER2-positive (HER2+) advanced gastric cancer. However, as seen in recent clinical trials, most of HER2+ gastric cancer are actually unresponsive to HER2-targeted agents, including lapatinib. The aim of this study is to identify the responsible receptor tyrosine kinases (RTK) potentially conferring lapatinib unresponsiveness in HER2+ gastric cancer and elucidate the molecular mechanism underlying this RTKs-induced resistance.

EXPERIMENTAL DESIGN

A functional RNAi screen targeting human RTKs and related growth factors was used to identify candidate RTKs conferring lapatinib unresponsiveness in HER2+ gastric cancer cells. Independent siRNAs transfection and corresponding ligands supplement were performed to validate the effects of candidate RTKs on lapatinib sensitivity. Cross-talks of pathways involved were analyzed via Western blot analysis. Cell apoptosis and cell motility were detected using FACS system and Transwell assay. Immunohistochemistry was used to analyze protein expression in clinical samples.

RESULTS

MET, HER3, insulin-like growth factor (IGF)-1R, and INSR were identified to mediate lapatinib unresponsiveness in HER2+ gastric cancer cells. Activation of these bypass RTKs attenuated lapatinib-induced apoptosis and suppression of cell motility, mechanistically because of restimulating the shared downstream AKT or ERK signaling, as well as restimulating WNT signaling and epithelial-to-mesenchymal transition (EMT)-like process. Patients' specimens revealed that these unresponsiveness-conferring RTKs were particularly enriched in the majority of patients with HER2+ gastric cancer.

CONCLUSIONS

MET, HER3, IGF1R, and INSR pathways activation represent novel mechanism underlying lapatinib unresponsiveness in HER2+ gastric cancer. Combination strategy may be recommended in treating patients with HER2+ gastric cancer with these pathways activation.

Positive expression of insulin-like growth factor-1 receptor is associated with a positive hormone receptor status and a favorable prognosis in breast cancer

PURPOSE

Insulin-like growth factor 1 receptor (IGF-1R) is commonly expressed in primary breast cancers. Understanding the role of IGF-1R signaling in the different subtypes of breast cancer is important because each subtype has a different outcome and requires different treatment modalities. However, the precise biological significance of IGF-1R expression in cancer cells is still unclear. In this study, we examined the expression of IGF-1R in the different molecular subtypes of breast cancer. The effects of IGF-1R expression on the survival rates and outcomes of breast cancer were also examined.

METHODS

IGF-1R expression was evaluated immunohistochemically in tissue microarray blocks constructed from 1,198 invasive breast cancer samples collected from six medical institutions. IGF-1R expression was interpreted according to the human epidermal growth factor receptor 2 (HER2)/neu immunohistochemistry scoring system. Scores of 2+ and 3+ were considered positive.

RESULTS

Positive IGF-1R expression was observed in 65.4% of invasive breast cancer samples. IGF-1R expression was detected in all cancer subtypes (luminal A, 84.4%; luminal B, 75.9%; HER2, 21.2%; triple-negative, 46.6%) and was found to be associated with a positive hormone receptor status and the absence of HER2 amplification (p<0.001). Positive IGF-1R expression was significantly associated with high survival rates (p=0.014). However, a multivariate analysis revealed that the expression levels of IGF-1R did not achieve statistical significance. In the triple-negative cancer subtype, IGF-1R expression was found to be associated with a lower disease-free survival rate (p=0.031).

CONCLUSION

Positive IGF-1R expression is associated with a favorable prognosis in breast cancer. IGF-1R is frequently expressed in the luminal A/B subtypes of breast cancer, and its expression is related to the hormone receptor status.

Her3 is associated with poor survival of gastric adenocarcinoma: Her3 promotes proliferation, survival and migration of human gastric cancer mediated by PI3K/AKT signaling pathway

ErbB3 (Her3) is a membrane-bound protein which can form heterodimers with other EGF receptor family members with kinase activity. Previous reports identified Her3 as a significant predictor of poor survival in human gastric cancer (GC), but its mechanism has remained unclear. We sought to investigate the mechanism of Her3 in GC and its association with clinical characteristics. Her3 was detected by both real-time PCR and immunohistochemistry (IHC) in 161 GC patients, and its related downstream signaling PI3K/AKT activity and clinical characteristics were accessed by statistical analysis. Her3 siRNA was used in both in vitro and in vivo assay to investigate the mechanism. Her3 expression was significantly increased in human GC compared with adjacent normal gastric tissues as observed by both real-time PCR and IHC. Her3 expression was associated with downstream AKT activation and increased tumor size, metastasis and poor survival in GC patients. Knockdown of Her3 in human GC cell line can inhibit cell proliferation and tumor growth both in vitro and in vivo by inactivation of AKT. Her3 knockdown had no observed impact on Her2 expression or activity. G2/M arrest was investigated due to decreased CyclinB1 and p27(kip1) at T157. Increased apoptosis occurred in Her3 silenced GC cell treated with cisplatin due to decreased BAD at S112. Moreover, Her3 silence can inhibit cell migration in vitro and metastasis in vivo by down-regulating MMPs via PI3K/AKT signaling. Her3 is a new prognostic factor associated with tumor growth and metastasis via PI3K/AKT signaling.

The emergence of targeted drugs in breast cancer to prevent resistance to endocrine treatment and chemotherapy

INTRODUCTION

Deregulated signaling pathways are associated with resistance to chemotherapy and endocrine treatment, providing a rationale for the implementation of novel targeted therapies in breast cancer therapy. Key molecules targeted therapeutically in ongoing clinical breast cancer trials are phosphoinositide 3-kinase-Akt-mammalian target of rapamycin (mTOR), Src, insulin-like growth factor 1 receptor, heat shock protein-90, histone deacetylases, cyclin-dependent kinases (CDKs), Notch and human epidermal growth factor receptors (HERs).

AREAS COVERED

This review provides an overview of novel targeted agents currently explored in clinical breast cancer trials and registered in ClinicalTrials.gov. The main focus will be on their ability to prevent or reverse endocrine resistance and chemoresistance in breast cancer.

EXPERT OPINION

HER2 targeted agents have extended survival substantially, both in the adjuvant and metastatic setting, pointing to a crucial dependency on this pathway in HER2-amplified breast cancer, including drug resistance reversal. While data on mTOR inhibitors are encouraging and preliminary results on CDK4/6 and Src inhibitors exciting, so far other targeted agents have been of limited benefit when added in concert with conventional therapies. Future clinical trials should systematically explore biomarkers and defects in functional gene cascades to identify relevant biological mechanisms to be targeted therapeutically in breast cancer.

Association of polymorphisms and haplotypes in the insulin-like growth factor 1 receptor (IGF1R) gene with the risk of breast cancer in Korean women

The insulin-like growth factor (IGF) signaling pathway plays an important role in cancer biology. The IGF 1 receptor (IGF1R) overexpression has been associated with a number of hematological neoplasias and solid tumors including breast cancer. However, molecular mechanism involving IGF1R in carcinogenic developments is clearly not known. We investigated the genetic variations across the IGF1R polymorphism and the risk of breast cancer risk in Korean women. A total of 1418 individuals comprising 1026 breast cancer cases and 392 age-matched controls of Korean were included for the analysis. Genomic DNA was extracted from whole blood and single nucleotide polymorphisms (SNPs) were analyzed on the GoldenGate Assay system by Illumina’s Custom Genetic Analysis service. SNPs were selected for linkage disequilibrium (LD) analysis by Haploview. We genotyped total 51 SNPs in the IGF1R gene and examined for association with breast cancer. All the SNPs investigated were in Hardy-Weinberg equilibrium. These SNPs tested were significantly associated with breast cancer risk, after correction for multiple comparisons by adjusting for age at diagnosis, BMI, age at menarche, and age at first parturition. Among 51 IGF1R SNPs, five intron located SNPs (rs8032477, rs7175052, rs12439557, rs11635251 and rs12916884) with homozygous genotype (variant genotype) were associated with decreased risk of breast cancer. Fisher’s combined p-value for the five SNPs was 0.00032. Three intron located SNPs with heterozygous genotypes also had decreased risk of breast cancer. Seven of the 51 IGF1R SNPs were in LD and in one haplotype block, and were likely to be associated with breast cancer risk. Overall, this case-control study demonstrates statistically significant associations between breast cancer risk and polymorphisms in IGF1R gene.