Novel anticancer targets: revisiting ERBB2 and discovering ERBB3

B-cell epitope peptide cancer vaccines: a new paradigm for combination immunotherapies with novel checkpoint peptide vaccine

In light of the numerous US FDA-approved humanized monoclonal antibodies (mAbs) for cancer immunotherapy, it is surprising that the advancement of B-cell epitope vaccines designed to elicit a natural humoral polyclonal antibody response has not gained traction in the immune-oncology landscape. Passive immunotherapy with humanized mAbs (Trastuzumab [Herceptin®]; Pertuzumab [Perjeta®]) has provided clinical benefit to breast cancer patients, albeit with significant shortcomings including toxicity problems and resistance, high costs, sophisticated therapeutic regimen and long half-life. The role of B-cell humoral immunity in cancer is under appreciated and underdeveloped. We have advanced the idea of active immunotherapy with chimeric B-cell epitope peptides incorporating a 'promiscuous' T-cell epitope that elicits a polyclonal antibody response, which provides safe, cost-effective therapeutic advantage over mAbs. We have created a portfolio of validated B-cell peptide epitopes against multiple receptor tyrosine kinases (HER-1, HER-3, IGF-1R and VEGF). We have successfully translated two HER-2 combination B-cell peptide vaccines in Phase I and II clinical trials. We have recently developed an effective novel PD-1 vaccine. In this article, I will review our approaches and strategies that focus on B-cell epitope cancer vaccines.

Targeted Therapies in Advanced Gastric Cancer

OPINION STATEMENT

Despite a decreasing incidence in the USA, gastric cancer is highly prevalent worldwide. Furthermore, gastric cancer remains highly lethal with median survival of less than 1 year for metastatic disease. The backbone of therapy against metastatic gastric cancer remains cytotoxic chemotherapy, but recent advances in the molecular understanding of gastric cancer have renewed hope within that targeted agents can be leveraged to improve survival and reduce toxicity. For example, in patients with human epidermal growth factor-2 (HER2)-positive gastric cancer, the addition of trastuzumab to frontline chemotherapy improves survival. In the second line, oncologists can now administer a vascular endothelial growth factor (VEGF) receptor inhibitor, ramucirumab, as a single agent or in combination with chemotherapy, and the immune checkpoint inhibitor pembrolizumab is approved in multiple settings dependent on the Programmed Death Ligand 1 (PD-L1) status. For patients with metastatic disease, our approach to standard of care in the first-line setting is a 5FU/platinum doublet with trastuzumab for HER2-positive tumors. In the second-line setting, most patients receive ramucirumab + paclitaxel, but those that are MSI high receive pembrolizumab. For squamous cell carcinoma of the esophagus with high PD-L1 status (combined positive score (CPS) ≥ 10), we recommend pembrolizumab in the second line. While for PD-L1 ≥ 1% gastroesophageal adenocarcinoma, we do not recommend pembrolizumab before the third-line setting, although this may change in the near future for CPS ≥ 10. The future landscape for targeted therapy in gastric cancer is promising. Numerous clinical trials evaluating the combination immune therapy with molecularly targeted agents are generating much excitement. Moreover, genomic data from The Cancer Center Genome (TCGA) and Asian Cancer Research Group (ACRG) classifications is being used to identify molecular subtypes to enable future clinical trials to include biomarker-enriched patient populations.

NIR Photodynamic Destruction of PDAC and HNSCC Nodules Using Triple-Receptor-Targeted Photoimmuno-Nanoconjugates: Targeting Heterogeneity in Cancer

Receptor heterogeneity in cancer is a major limitation of molecular targeting for cancer therapeutics. Single-receptor-targeted treatment exerts selection pressures that result in treatment escape for low-receptor-expressing tumor subpopulations. To overcome this potential for heterogeneity-driven resistance to molecular targeted photodynamic therapy (PDT), we present for the first time a triple-receptor-targeted photoimmuno-nanoconjugate (TR-PIN) platform. TR-PIN functionalization with cetuximab, holo-transferrin, and trastuzumab conferred specificity for epidermal growth factor receptor (EGFR), transferrin receptor (TfR), and human epidermal growth factor receptor 2 (HER-2), respectively. The TR-PINs exhibited up to a 24-fold improvement in cancer cell binding compared with EGFR-specific cetuximab-targeted PINs (Cet-PINs) in low-EGFR-expressing cell lines. Photodestruction using TR-PINs was significantly higher than the monotargeted Cet-PINs in heterocellular 3D in vitro models of heterogeneous pancreatic ductal adenocarcinoma (PDAC; MIA PaCa-2 cells) and heterogeneous head and neck squamous cell carcinoma (HNSCC, SCC9 cells) containing low-EGFR-expressing T47D (high TfR) or SKOV-3 (high HER-2) cells. Through their capacity for multiple tumor target recognition, TR-PINs can serve as a unique and amenable platform for the effective photodynamic eradication of diverse tumor subpopulations in heterogeneous cancers to mitigate escape for more complete and durable treatment responses.

miR‑135b‑5p enhances the sensitivity of HER‑2 positive breast cancer to trastuzumab via binding to cyclin D2

Trastuzumab has led to a marked improvement in the outcomes of patients with human epidermal growth factor receptor 2 (HER-2)-positive breast cancer. However, the effects of trastuzumab on HER-2-positive breast cancer are limited by the emergence of its cardiotoxicside effects. MicroRNA (miR)-135b-5p has been shown to inhibit tumor metastasis in breast cancer. The present study aimed to explore the effects of miR-135b-5p overexpression on the efficacy of trastuzumab in HER-2-positive breast cancer. Reverse transcription-quantitative PCR was performed to detect the levels of miR-135b-5p. Cell viability was evaluated with a Cell Counting Kit-8 assay. Annexin V/propidium iodide staining was employed to detect the number of apoptotic cells. Flow cytometry assay was performed to investigate the cell cycle. Western blotting was used to detect the expression levels of Bax, cleaved caspase-3, Bcl-2, cyclin D2, p27^Kip1 and cyclin E1. Cell migration and invasion were detected by Transwell assay. Luciferase assays were conducted to identify the target gene of miR-135b-5p. In addition, an in vivo tumor xenograft model was established. miR-135b-5p agomir significantly enhanced the anti-proliferative effect of trastuzumab on HER-2-positive breast cancer cells via the induction of apoptosis, whereas the anti-metastatic effect of trastuzumab was enhanced by miR-135b-5p agomir treatment. Subsequently, luciferase assays indicated that cyclin D2 was the direct target of miR-135b-5p, whereas overexpression of the latter arrested cell cycleduring the G₀/G₁ phase. Moreover, miR-135b-5p agomir notably increased the antitumor effect of trastuzumab in vivo. The data demonstrated that miR-135b-5p sensitized HER-2-positive breast cancer cells to trastuzumab in vitro and in vivo by directly binding to cyclin D2. These results suggested that the combination of miR-135b-5p with trastuzumab may be a therapeutic strategy for patients with HER-2-positive breast cancer.

Nrf2 Inhibitor, Brusatol in Combination with Trastuzumab Exerts Synergistic Antitumor Activity in HER2-Positive Cancers by Inhibiting Nrf2/HO-1 and HER2-AKT/ERK1/2 Pathways

The HER2-targeting antibody trastuzumab has shown effectiveness in treating HER2-positive breast and gastric cancers; however, its responses are limited. Currently, Nrf2 has been deemed as a key transcription factor in promoting cancer progression and resistance by crosstalk with other proliferative signaling pathways. Brusatol as a novel Nrf2 inhibitor has been deemed as an efficacious and safe drug candidate in cancer therapy. In this study, we firstly reported that brusatol exerted the growth-inhibitory effects on HER2-positive cancer cells by regressing Nrf2/HO-1 and HER2-AKT/ERK1/2 signaling pathways in these cells. More importantly, we found that brusatol synergistically enhanced the antitumor activity of trastuzumab against HER2-positive SK-OV-3 and BT-474 cells, which may be attributed to the inhibition of Nrf2/HO-1 and HER2-AKT/ERK1/2 signaling pathways. Furthermore, the synergistic effects were also observed in BT-474 and SK-OV-3 tumor xenografts. In addition, our results showed that trastuzumab markedly enhanced brusatol-induced ROS accumulation and apoptosis level, which could further explain the synergistic effects. To conclude, the study provided a new insight on exploring Nrf2 inhibition in combination with HER2-targeted trastuzumab as a potential clinical treatment regimen in treating HER2-positive cancers.

Working together for the family: determination of HER oncogene co-amplifications in breast cancer

HER2 is a well-studied tyrosine kinase (TK) membrane receptor which functions as a therapeutic target in invasive ductal breast carcinomas (IDC). The standard of care for the treatment of HER2-positive breast is the antibody trastuzumab. Despite specific treatment unfortunately, 20% of primary and 70% of metastatic HER2 tumors develop resistance. HER2 belongs to a gene family, with four members (HER1-4) and these members could be involved in resistance to anti-HER2 therapies. In this study we designed a probemix to detect the amplification of the four HER oncogenes in a single reaction. In addition, we developed a protocol based on the combination of MLPA with ddPCR to detect the tumor proportion of co-amplified HERs. On 111 IDC, the HER2 MLPA results were validated by FISH (Adjusted r ² = 0,91, p < 0,0001), CISH (Adjusted r ² = 0,938, p < 0,0001) and IHC (Adjusted r ² = 0,31, p < 0,0001). HER1-4 MLPA results were validated by RT-qPCR assays (Spearman Rank test p < 0,05). Of the 111 samples, 26% presented at least one HER amplified, of which 23% showed co-amplifications with other HERs. The percentage of cells with HER2 co-amplified varied among the tumors (from 2-72,6%). Independent in-silico findings show that the outcome of HER2+ patients is conditioned by the status of HER3 and HER4. Our results encourage further studies to investigate the relationship with patient's response to single or combined treatment. The approach could serve as proof of principle for other tumors in which the HER oncogenes are involved.

The Role of Tyrosine Kinases as a Critical Prognostic Parameter and Its Targeted Therapies in Ewing Sarcoma

Ewing sarcoma (ES) is a rare, highly aggressive, bone, or soft tissue-associated tumor. Although this sarcoma often responds well to initial chemotherapy, 40% of the patients develop a lethal recurrence of the disease, with death recorded in 75-80% of patients with metastatic ES within 5 years, despite receiving high-dose chemotherapy. ES is genetically well-characterized, as indicated by the EWS-FLI1 fusion protein encoded as a result of chromosomal translocation in 80-90% of patients with ES, as well as in ES-related cancer cell lines. Recently, tyrosine kinases have been identified in the pathogenesis of ES. These tyrosine kinases, acting as oncoproteins, are associated with the clinical pathogenesis, metastasis, acquisition of self-renewal traits, and chemoresistance of ES, through the activation of various intracellular signaling pathways. This review describes the recent progress related to cellular and molecular functional roles of tyrosine kinases in the progression of ES.

Molecular targeted therapies: Ready for "prime time" in biliary tract cancer

The prognosis for patients with biliary tract cancers (cholangiocarcinoma and gallbladder cancer) is poor, while the incidence of these cancers is increasing. Most patients are diagnosed with advanced disease when treatment options are limited to palliative approaches, mainly focused on chemotherapy. In recent years, novel treatment targets of relevance to biliary tract cancers, mainly present in patients with intrahepatic cholangiocarcinoma, have been identified and are rapidly changing the field. These include fibroblast growth factor receptor (FGFR) fusions and isocitrate dehydrogenase (IDH)-1 and -2 mutations which are each present in around 10-20% of patients with intrahepatic cholangiocarcinoma. In addition, inhibition of other pathways/molecules is currently being explored, including human epidermal growth factor receptor (HER) family members, the Wnt pathway, neurotropic tyrosine kinase receptor (NTRK) fusions and BRAF mutations. The IDH1 inhibitor ivosidenib has already been tested in a phase III clinical trial in pretreated cholangiocarcinoma and showed benefit in terms of progression-free survival. Multiple FGFR inhibitors have consistently shown high response rates in phase II/III trials, especially for patients harbouring FGFR2 fusions. Herein, we provide an overview of the status of targeted therapies in biliary tract cancers, discussing the current clinical development of IDH and FGFR inhibitors in detail, as well as reviewing current caveats and future steps.

Biomarkers for HER2-positive metastatic breast cancer: Beyond hormone receptors

The overexpression of human epidermal growth factor receptor-2 (HER2) results in a biologically and clinically aggressive breast cancer (BC) subtype. Since the introduction of anti-HER2 targeted agents, survival rates of patients with HER2-positive metastatic BC have dramatically improved. Currently, although the treatment decision process in metastatic BC is primarily based on HER2 and hormone-receptor (HR) status, a rapidly growing body of data suggests that several other sources of biological heterogeneity may characterize HER2-positive metastatic BC. Moreover, pivotal clinical trials of new anti-HER2 antibody-drug conjugates showed encouraging results in HER2-low metastatic BC, thus leading to the possibility, in the near future, to expand the pool of patients suitable for HER2-targeted treatments. The present review summarizes and puts in perspective available evidence on biomarkers that hold the greatest promise to become potentially useful tools for optimizing HER2-positive metastatic BC patients' prognostic stratification and treatment in the next future. These biomarkers include HER2 levels and heterogeneity, HER3, intrinsic molecular subtypes by PAM50 analysis, DNA mutations, and immune-related factors. Molecular discordance between primary and metastatic tumors is also discussed.

Oncogene-Addicted Non-Small-Cell Lung Cancer: Treatment Opportunities and Future Perspectives

Before the introduction of tyrosine kinase inhibitors (TKIs) for a particular subgroup of patients, despite platinum-based combination chemotherapy, the majority of patients affected by non-small-cell lung cancer (NSCLC) did not live longer than one year. With deeper understanding of tumor molecular biology, treatment of NSCLC has progressively entered the era of treatment customization according to tumor molecular characteristics, as well as histology. All this information allowed the development of personalized molecular targeted therapies. A series of studies have shown that, in some cases, cancer cells can grow and survive as result of the presence of a single driver genomic abnormality. This phenomenon, called oncogene-addiction, more often occurs in adenocarcinoma histology, in non-smokers (except BRAF mutations, also frequent in smoking patients), young, and female patients. Several different driver mutations have been identified and many studies have clearly shown that upfront TKI monotherapy may improve the overall outcome of these patients. The greater efficacy of these drugs is also associated with a better tolerability and safety than chemotherapy, with fewer side effects and an extremely good compliance to treatment. The most frequent oncogene-addicted disease is represented by those tumors carrying a mutation of the epidermal growth factor receptor (EGFR). The development of first, second and third generation TKIs against EGFR mutations have dramatically changed the prognosis of these patients. Currently, osimertinib (which demonstrated to improve efficacy with a better tolerability in comparison with first-generation TKIs) is considered the best treatment option for patients affected by NSCLC harboring a common EGFR mutation. EML4-ALK-driven disease (which gene re-arrangement occurs in 3-7% of NSCLC), has demonstrated to be significantly targeted by specific TKIs, which have improved outcome in comparison with chemotherapy. To date, alectinib is considered the best treatment option for these patients, with other newer agents upcoming. Other additional driver abnormalities, such as ROS1, BRAF, MET, RET and NTRK, have been identified as a target mirroring peculiar vulnerability to specific agents. Oncogene-addicted disease typically has a low early resistance rate, but late acquired resistance always develops and therefore therapy needs to be changed when progression occurs. In this narrative review, the state of art of scientific literature about targeted therapy options in oncogene-addicted disease is summarized and critically discussed. We also aim to analyze future perspectives to maximize benefits for this subgroup of patients.

HER3 targeting with an antibody-drug conjugate bypasses resistance to anti-HER2 therapies

Despite impressive clinical benefit obtained with anti‐HER2‐targeted therapies, in advances stages, especially in the metastatic setting, HER2‐positive tumors remain incurable. Therefore, it is important to develop novel strategies to fight these tumors, especially when they become resistant to available therapies. We show here that the anti‐HER3 antibody–drug conjugate EV20/MMAF exerted potent anti‐tumoral properties against several models of primary resistance and secondary resistance to common anti‐HER2 available therapies, including trastuzumab, lapatinib, neratinib, and trastuzumab‐emtansine. HER3 was expressed in these HER2⁺ breast cancer cells and knockdown experiments demonstrated that HER3 expression was required for the action of EV20/MMAF. In mice injected with trastuzumab‐resistant HER2⁺ cells, a single dose of EV20/MMAF caused complete and long‐lasting tumor regression. Mechanistically, EV20/MMAF bound to cell surface HER3 and became internalized to the lysosomes. Treatment with EV20/MMAF caused cell cycle arrest in mitosis and promoted cell death through mitotic catastrophe. These findings encourage the clinical testing of EV20/MMAF for several indications in the HER2⁺ cancer clinic, including situations in which HER2⁺ tumors become refractory to approved anti‐HER2 therapies.

Trastuzumab, Pertuzumab, and Docetaxel as the First Line for HER-2-Positive Metastatic Breast Cancer among Arabs

Introduction

Human epidermal growth factor receptor 2 (HER-2) targeted therapy regimens can improve tumor response in HER-2-positive metastatic breast cancer (MBC), with overall survival benefits.

Objective

We evaluated the efficacy of dual HER-2 blockade combined with chemotherapy for HER-2-positive MBC patients as a first-line therapy in our patient population.

Patients and Methods

We identified 75 patients at King Faisal Specialist Hospital and Research Center that received trastuzumab, pertuzumab, and docetaxel as a first-line therapy in HER-2 positive MBC in 2013-2016.

Results

Median age at diagnosis was 45 years; 54.7% were estrogen receptor (ER)-positive. 10% of patients presented with only bone metastasis. The median follow-up time was 36 months with an objective response rate of 74.7% (complete response [CR] 18.7%; partial response [PR] 56%). The 5-year progression-free survival (PFS) and overall survival (OS) were 21% and 71.9% respectively, with a median PFS of 36 months (95% confidence interval [CI] 23.6-48.4). The 5-year OS for ER-negative and ER-positive patients was 93.9% and 59.4% respectively (p = 0.189); 23 patients experienced grade 1/2 toxicity and 2 patients had grade 3/4 toxicity. In terms of OS and PFS, the site of metastasis did not make any significant difference.

Conclusions

First line pertuzumab, trastuzumab, and docetaxel for HER-2-positive MBC patients was found to be an effective and safe therapy in the Saudi population. This finding was consistent with the results seen in the CLEOPATRA trials.

Hyper-Graph Regularized Constrained NMF for Selecting Differentially Expressed Genes and Tumor Classification

Non-negative Matrix Factorization (NMF) is a dimensionality reduction approach for learning a parts-based and linear representation of non-negative data. It has attracted more attention because of that. In practice, NMF not only neglects the manifold structure of data samples, but also overlooks the priori label information of different classes. In this paper, a novel matrix decomposition method called Hyper-graph regularized Constrained Non-negative Matrix Factorization (HCNMF) is proposed for selecting differentially expressed genes and tumor sample classification. The advantage of hyper-graph learning is to capture local spatial information in high dimensional data. This method incorporates a hyper-graph regularization constraint to consider the higher order data sample relationships. The application of hyper-graph theory can effectively find pathogenic genes in cancer datasets. Besides, the label information is further incorporated in the objective function to improve the discriminative ability of the decomposition matrix. Supervised learning with label information greatly improves the classification effect. We also provide the iterative update rules and convergence proofs for the optimization problems of HCNMF. Experiments under The Cancer Genome Atlas (TCGA) datasets confirm the superiority of HCNMF algorithm compared with other representative algorithms through a set of evaluations.

Spectrum of EGFR aberrations and potential clinical implications: insights from integrative pan-cancer analysis

Background

Human epidermal growth factor receptor (EGFR) is an oncogenic gene and one of top targets of precision therapy in lung cancer with EGFR mutations. Although there are many reports for some individual cancers, comprehensive profiling of EGFR mutations, overexpression, amplification, DNA methylation, and their clinical associations across many different cancers simultaneously was not available. This study aimed to fill the gap and provide insights to the alteration spectrum of EGFR and its therapeutic and prognostic implications.

Methods

The Cancer Genome Atlas (TCGA) datasets for 32 cancer types involving 11,314 patients were analyzed for alterations (mutations and amplification/deletion), abnormal expression and DNA methylation in EGFR gene. Mutation frequency, genomic location distribution, functional impact, and clinical targeted therapy implication were compared among different cancer types, and their associations with patient survival were analyzed.

Results

EGFR alteration frequency, mutation sites across functional domains, amplification, overexpression, and DNA methylation patterns differed greatly among different cancer types. The overall mutation frequency in all cancers combined was relatively low. Targetable mutations, mainly in lung cancer, were primarily found in the Pkinase_Tyr domain. Glioblastoma multiforme had the highest rate of alterations, but it was dominated by gene amplification and most mutations were in the Furin‐like domain where targeted therapy was less effective. Low‐grade glioma often had gene amplification and increased EGFR expression which was associated with poor outcome. Colon and pancreatic adenocarcinoma had very few EGFR mutations; however, high EGFR expression was significantly associated with short patient survival. Squamous cell carcinoma regardless of their sites (the head and neck, lung, or esophagus) exhibited similar characteristics with an alteration frequency of about 5.0%, was dominated by gene amplification, and had increased EGFR expression generally associated with short patient survival. DNA methylation was highly associated with EGFR expression and patient outcomes in some cancers.

Conclusions

EGFR aberration type, frequency, distribution in functional domains, and expression vary from cancer to cancer. While mutations in the Pkinase_Tyr domain are more important for treatment selection, increased expression from amplification or deregulation affects more tumor types and leads to worse outcome, which calls for new treatment strategies for these EGFR‐driven tumors.

Role of MEL-18 Amplification in Anti-HER2 Therapy of Breast Cancer

BACKGROUND

Resistance to HER2-targeted therapy with trastuzumab still remains a major challenge in HER2-amplified tumors. Here we investigated the potential role of MEL-18, a polycomb group gene, as a novel prognostic marker for trastuzumab resistance in HER2-positive (HER2+) breast cancer.

METHODS

The genetic alteration of MEL-18 and its clinical relevance were examined in multiple breast cancer cohorts including METABRIC (n = 1,980), TCGA (n = 825), and our clinical specimens (n = 213, trastuzumab-treated HER2+ cases). MEL-18 amplification was validated by fluorescence in situ hybridization (FISH) analysis. The MEL-18 effect on trastuzumab response was confirmed by in vitro cell viability assays and an in vivo xenograft experiment (n = 7 per group). Gene expression microarray and receptor tyrosine kinase array were performed to identify the trastuzumab resistance mechanism by MEL-18 loss. All statistical tests were two-sided.

RESULTS

MEL-18 was exclusively amplified in approximately 30-50% of HER2+ breast tumors and was associated with a favorable clinical outcome (disease-free survival: P = .02 in HER2+ cases, METABRIC; P = .04 in patients receiving trastuzumab). In MEL-18-amplified HER2+ breast cancer, MEL-18 depletion induced trastuzumab resistance by increasing ADAM sheddase-mediated ErbB ligand production and receptor heterodimerization. MEL-18 epigenetically silenced ADAM10/17 expression in cooperation with polycomb-repressive complex (PRC) 1 and PRC2. Combination treatment with an ADAM10/17 inhibitor and trastuzumab could overcome MEL-18 loss-mediated trastuzumab resistance in vivo (BT474/shMEL-18 xenograft: trastuzumab, mean [SD] tumor volume = 406.1 [50.1] mm3, vs trastuzumab + GW280264 30 mg/kg, mean [SD] tumor volume = 68.4 [15.6] mm3, P < .001). Consistently, trastuzumab-treated patients harboring concomitant MEL-18 amplification and low ADAM17 expression showed prolonged relapse-free survival (P = .02 in our cohort, n = 213).

CONCLUSION

MEL-18 serves to prevent ligand-dependent ErbB heterodimerization and trastuzumab resistance, suggesting MEL-18 amplification as a novel biomarker for HER2+ breast cancer.

Inhibitory Effect of Polyclonal Antibodies Against HER3 Extracellular Subdomains on Breast Cancer Cell Lines

Objective:

Human epidermal growth factor receptor 3 (HER3) is a unique member of the tyrosine kinase receptors with an inactive kinase domain and is the preferable dimerization partner for HER2 which lead to potent tumorigenic signaling.

Methods:

In this study, the expression plasmids coding for the human HER3 subdomains were transfected into CHO-K1 cells. Produced proteins were characterized by ELISA and SDS-PAGE. Rabbits were immunized and produced polyclonal antibodies (pAbs) that were characterized by ELISA, Immunoblotting and flowcytometry and their inhibitory effects were assessed by XTT on BT-474 and JIMT-1 breast cancer cell lines.

Result:

The recombinant subdomains were highly immunogenic in rabbits. The pAbs reacted with the recombinant subdomains as well as commercial HER3 and the native receptor on tumor cell membranes and could significantly inhibit growth of Trastuzumab sensitive (BT-474) and resistant (JIMT-1) breast cancer cell lines in vitro.

Conclusion:

It seems that HER3 extra cellular domains (ECD) induce a strong anti-tumor antibody response and may prove to be potentially useful for immunotherapeutic applications.

Targeting the EphB4 receptor tyrosine kinase sensitizes HER2-positive breast cancer cells to Lapatinib

Clinical data analysis reveals that the expression of the EphB4 receptor tyrosine kinase is significantly elevated in HER2-positive breast cancer and high levels of EphB4 strongly correlate with poor disease prognosis. However, the impact of EphB4 activation on HER2-positive breast cancer cells and the potential of EphB4 as a therapeutic target remain to be explored. Here, we show that EphB4 overexpression confers gain-of-function activities to HER2-positive breast cancer cells, rendering resistance to a HER2/EGFR inhibitor Lapatinib. Furthermore, using integrated transcriptomic and tyrosine phosphoproteomic analyses, followed by biochemical confirmation, we establish that EphB4 activation engages the SHP2/GAB1-MEK signaling cascade and downstream c-MYC activation, and thereby limits the overall drug responses to Lapatinib. Finally, we demonstrate that, in HER2-positive breast tumors, inhibition of EphB4 combined with Lapatinib is more effective than either alone. These findings provide new insights into the signaling networks dictating therapeutic response to Lapatinib as well as a rationale for co-targeting EphB4 in HER2-positive breast cancer.

10D1F, an Anti-HER3 Antibody that Uniquely Blocks the Receptor Heterodimerization Interface, Potently Inhibits Tumor Growth Across a Broad Panel of Tumor Models

In recent years, HER3 has increasingly been implicated in the progression of a variety of tumor types and in acquired resistance to EGFR and HER2 therapies. Whereas EGFR and HER2 primarily signal through the MAPK pathway, HER3, as a heterodimer with EGFR or HER2, potently activates the PI3K pathway. Despite its critical role, previous attempts to target HER3 with neutralizing antibodies have shown disappointing efficacy in the clinic, most likely due to suboptimal and indirect mechanisms of action that fail to completely block heterodimerization; for example, tumors can escape inhibition of ligand binding by upregulating ligand-independent mechanisms of HER3 activation. We therefore developed 10D1F, a picomolar affinity, highly specific anti-HER3 neutralizing antibody that binds the HER3 heterodimerization interface, a region that was hitherto challenging to raise antibodies against. We demonstrate that 10D1F potently inhibits both EGFR:HER3 and HER2:HER3 heterodimerization to durably suppress activation of the PI3K pathway in a broad panel of tumor models. Even as a monotherapy, 10D1F shows superior inhibition of tumor growth in the same cell lines both in vitro and in mouse xenograft experiments, when compared with other classes of anti-HER3 antibodies. This includes models demonstrating ligand-independent activation of heterodimerization as well as constitutively activating mutations in the MAPK pathway. Possessing favorable pharmacokinetic and toxicologic profiles, 10D1F uniquely represents a new class of anti-HER3 neutralizing antibodies with a novel mechanism of action that offers significant potential for broad clinical benefit.10D1F is a novel anti-HER3 antibody that uniquely binds the receptor dimerization interface to block ligand-dependent and independent heterodimerization with EGFR/HER2 and thus more potently inhibits tumor growth than existing anti-HER3 antibodies.

Novel functional anti-HER3 monoclonal antibodies with potent anti-cancer effects on various human epithelial cancers

Resistance of progressive cancers against chemotherapy is a serious clinical problem. In this context, human epidermal growth factor receptor 3 (HER3) can play important roles in drug resistance to HER1- and HER2- targeted therapies. Since clinical testing of anti-HER3 monoclonal antibodies (mAbs) such as patritumab could not show remarkable effect compared with existing drugs, we generated novel mAbs against anti-HER3. Novel rat mAbs reacted with HEK293 cells expressing HER3, but not with cells expressing HER1, HER2 or HER4. Specificity of mAbs was substantiated by the loss of mAb binding with knockdown by siRNA and knockout of CRISPR/Cas9-based genome-editing. Analyses of CDR sequence and germline segment have revealed that seven mAbs are classified to four groups, and the binding of patritumab was inhibited by one of seven mAbs. Seven mAbs have shown reactivity with various human epithelial cancer cells, strong internalization activity of cell-surface HER3, and inhibition of NRG1 binding, NRG1-dependent HER3 phosphorylation and cell growth. Anti-HER3 mAbs were also reactive with in vivo tumor tissues and cancer tissue-originated spheroid. Ab4 inhibited in vivo tumor growth of human colon cancer cells in nude mice. Present mAbs may be superior to existing anti-HER3 mAbs and support existing anti-cancer therapeutic mAbs.

SMYD3: An Oncogenic Driver Targeting Epigenetic Regulation and Signaling Pathways

SMYD3 is a member of the SMYD lysine methylase family and plays an important role in the methylation of various histone and non-histone targets. Aberrant SMYD3 expression contributes to carcinogenesis and SMYD3 upregulation was proposed as a prognostic marker in various solid cancers. Here we summarize SMYD3-mediated regulatory mechanisms, which are implicated in the pathophysiology of cancer, as drivers of distinct oncogenic pathways. We describe SMYD3-dependent mechanisms affecting cancer progression, highlighting SMYD3 interplay with proteins and RNAs involved in the regulation of cancer cell proliferation, migration and invasion. We also address the effectiveness and mechanisms of action for the currently available SMYD3 inhibitors. The findings analyzed herein demonstrate that a complex network of SMYD3-mediated cytoplasmic and nuclear interactions promote oncogenesis across different cancer types. These evidences depict SMYD3 as a modulator of the transcriptional response and of key signaling pathways, orchestrating multiple oncogenic inputs and ultimately, promoting transcriptional reprogramming and tumor transformation. Further insights into the oncogenic role of SMYD3 and its targeting of different synergistic oncogenic signals may be beneficial for effective cancer treatment.

Contribution of synergism between PHF8 and HER2 signalling to breast cancer development and drug resistance

BACKGROUND

HER2 plays a critical role in tumourigenesis and is associated with poor prognosis of patients with HER2-positive breast cancers. Although anti-HER2 drugs are beneficial for treating breast cancer, de novo, or acquired resistance often develops. Epigenetic factors are increasingly targeted for therapy; however, such mechanisms that interact with HER2 signalling are poorly understood.

METHODS

RNA sequencing was performed to identify PHF8 targets downstream of HER2 signalling. CHIP-qPCR were used to investigate how PHF8 regulates HER2 transcription. ELISA determined cytokine secretion. Cell-based assay revealed a feed forward loop in HER2 signalling and then evaluated in vivo.

FINDINGS

We report the synergistic interplay between histone demethylase PHF8 and HER2 signalling. Specifically, PHF8 levels were elevated in HER2-positive breast cancers and upregulated by HER2. PHF8 functioned as a coactivator that regulated the expression of HER2, markers of the HER2-driven epithelial-to-mesenchymal transition and cytokines. The HER2-PHF8-IL-6 regulatory axis was active in cell lines and in newly established MMTV-Her2/MMTV-Cre/Phf8fl°x/fl°x mouse models, which revealed the oncogenic function of Phf8 in breast cancer for the first time. Further, the PHF8-IL-6 axis contributed to the resistance to trastuzumab in vitro and may play a critical role in the infiltration of T cells in HER2-driven breast cancers.

INTERPRETATION

These findings provided informative mechanistic insight into the potential application of PHF8 inhibitors to overcome resistance to anti-HER2 therapies.

FUNDING

This work was supported by Carver Trust Young Investigator Award (01-224 to H.H.Q); and a Breast Cancer Research Award (to H.H.Q.).

Anti-Tumor Effects of Osthole on Different Malignant Tissues: A Review of Molecular Mechanisms

Cancer management and/or treatment require a comprehensive understanding of the molecular and signaling pathways involved. Recently, much attention has been directed to these molecular and signaling pathways, and it has been suggested that a number of biomolecules/players involved in such pathways, such as PI3K/Akt, NF-kB, STAT, and Nrf2 contribute to the progression, invasion, proliferation, and metastasis of malignant cells. Synthetic anti-tumor agents and chemotherapeutic drugs have been a mainstay in cancer therapy and are widely used to suppress the progression and, hopefully, halt the proliferation of malignant cells. However, these agents have some undesirable side-effects and, therefore, naturally-occurring compounds with high potency and fewer side-effects are now of great interest. Osthole is a plant-derived chemical compound that can inhibit the proliferation of malignant cells and provide potent anti-cancer effects in various tissues. Therefore, in this review, we presented the main findings concerning the potential anti-tumor effects of osthole and its derivatives and described possible molecular mechanisms by which osthole may suppress malignant cell proliferation in different tissues.

Nanotechnology, in silico and endocrine-based strategy for delivering paclitaxel and miRNA: Prospects for the therapeutic management of breast cancer

Breast cancer is one of the most prevalent and reoccurring cancers and the second most common reason of death in women. Despite advancements in therapeutic strategies for breast cancer, early tumor recurrence and metastasis in patients indicate resistance to chemotherapeutic medicines, such as paclitaxel due to the abnormal expression of ER and EGF2 in breast cancer cells. Therefore, the development of alternatives to paclitaxel is urgently needed to overcome challenges involving drug resistance. An increasing number of studies has revealed miRNAs as novel natural alternative substances that play a crucial role in regulating several physiological processes and have a close, adverse association with several diseases, including breast cancer. Due to the therapeutic potential of miRNA and paclitaxel in cancer research, the current review focuses on the differential roles of various miRNAs in breast cancer development and treatment. miRNA delivery to a specific target site, the development of paclitaxel and miRNA formulations, and nanotechnological strategies for the delivery of nanopaclitaxel in the management of breast cancer are discussed. These strategies involve improving the cellular uptake and bioavailability and reducing the toxicity of free paclitaxel to achieve accumulation tumor site. Furthermore, a molecular docking study was performed to ascertain the enhanced anticancer activity of the nanoformulation of ANG1005 and Abraxane. An in silico analysis revealed that ANG1005 and Abraxane nanoformulations have superior and significantly enhanced interactions with the proteins α-tubulin and Bcl-2. Therefore, ANG1005 and Abraxane may be more suitable in the therapeutic management of breast cancer than the existing free paclitaxel. miRNAs can revert abnormal gene expression to normalcy; since miRNAs serve as tumor suppressors. Therefore, restoration of particular miRNAs levels as a replacement therapy may be an effective endocrine potential strategy for treating ER positive/ negative breast cancers.

Neuropeptide bombesin receptor activation stimulates growth of lung cancer cells through HER3 with a MAPK-dependent mechanism

Despite recent advances in treatment of non-small cell lung cancer (NSCLC), prognosis still remains poor and new therapeutic approaches are needed. Studies demonstrate the importance of the EGFR/HER-receptor family in NSCLC growth, as well as that of other tumors. Recently, HER3 is receiving increased attention because of its role in drug resistance and aggressive growth. Activation of overexpressed G-protein-coupled receptors (GPCR) can also initiate growth by transactivating EGFR/HER-family members. GPCR transactivation of EGFR has been extensively studied, but little is known of its ability to transactivate other EGFR/HER-members, especially HER3. To address this, we studied the ability of bombesin receptor (BnR) activation to transactivate all EGFR/HER-family members and their principal downstream signaling cascades, the PI3K/Akt- and MAPK/ERK-pathways, in human NSCLC cell-lines. In all three cell-lines studied, which possessed EGFR, HER2 and HER3, Bn rapidly transactivated EGFR, HER2 and HER3, as well as Akt and ERK. Immunoprecipitation studies revealed Bn-induced formation of both HER3/EGFR- and HER3/HER2-heterodimers. Specific EGFR/HER3 antibodies or siRNA-knockdown of EGFR and HER3, demonstrated Bn-stimulated activation of EGFR/HER members is initially through HER3, not EGFR. In addition, specific inhibition of HER3, HER2 or MAPK, abolished Bn-stimulated cell-growth, while neither EGFR nor Akt inhibition had an effect. These results show HER3 transactivation mediates all growth effects of BnR activation through MAPK. These results raise the possibility that targeting HER3 alone or with GPCR activation and its signal cascades, may be a novel therapeutic approach in NSCLC. This is especially relevant with the recent development of HER3-blocking antibodies.

Nectin-4 cis-interacts with ErbB2 and its trastuzumab-resistant splice variants, enhancing their activation and DNA synthesis

Nectin-4 cell adhesion molecule and ErbB2 tyrosine kinase receptor are upregulated in many cancers, including breast cancer, and promote cancer cell proliferation and metastasis. Using human breast cancer cell lines T47D and SUM190-PT, in which both nectin-4 and ErbB2 were upregulated, we showed here that nectin-4 cis-interacted with ErB2 and enhanced its dimerization and activation, followed by the activation of the phosphoinositide 3-kinase-AKT signalling pathway for DNA synthesis. The third immunoglobulin-like domain of nectin-4 cis-interacted with domain IV of ErbB2. This region differs from the trastuzumab-interacting region but is included in the trastuzumab-resistant splice variants of ErbB2, p95-ErbB2 and ErbB2ΔEx16. Nectin-4 also cis-interacted with these trastuzumab-resistant splice variants and enhanced the activation of the phosphoinositide 3-kinase-AKT signalling pathway for DNA synthesis. In addition, nectin-4 enhanced the activation of the p95-ErbB2-induced JAK-STAT3 signalling pathway, but not the ErbB2- or ErbB2ΔEx16-induced JAK-STAT3 signalling pathway. These results indicate that nectin-4 cis-interacts with ErbB2 and its trastuzumab-resistant splice variants and enhances the activation of these receptors and downstream signalling pathways in a novel mechanism.

The many substrates and functions of NEDD4-1

Tumorigenesis, tumor growth, and prognosis are highly related to gene alterations and post-translational modifications (PTMs). Ubiquitination is a critical PTM that governs practically all aspects of cellular function. An increasing number of studies show that E3 ubiquitin ligases (E3s) are important enzymes in the process of ubiquitination that primarily determine substrate specificity and thus need to be tightly controlled. Among E3s, neural precursor cell expressed developmentally downregulated 4-1 (NEDD4-1) has been shown to play a critical role in modulating the proliferation, migration, and invasion of cancer cells and the sensitivity of cancer cells to anticancer therapies via regulating multiple substrates. This review discusses some significant discoveries on NEDD4-1 substrates and the signaling pathways in which NEDD4-1 participates. In addition, we introduce the latest potential therapeutic strategies that inhibit or activate NEDD4-1 activity using small molecules. NEDD4-1 likely acts as a novel drug target or diagnostic marker in the battle against cancer.

Photoimmunotherapy of Ovarian Cancer: A Unique Niche in the Management of Advanced Disease

Ovarian cancer (OvCa) is the leading cause of gynecological cancer-related deaths in the United States, with five-year survival rates of 15-20% for stage III cancers and 5% for stage IV cancers. The standard of care for advanced OvCa involves surgical debulking of disseminated disease in the peritoneum followed by chemotherapy. Despite advances in treatment efficacy, the prognosis for advanced stage OvCa patients remains poor and the emergence of chemoresistant disease localized to the peritoneum is the primary cause of death. Therefore, a complementary modality that is agnostic to typical chemo- and radio-resistance mechanisms is urgently needed. Photodynamic therapy (PDT), a photochemistry-based process, is an ideal complement to standard treatments for residual disease. The confinement of the disease in the peritoneal cavity makes it amenable for regionally localized treatment with PDT. PDT involves photochemical generation of cytotoxic reactive molecular species (RMS) by non-toxic photosensitizers (PSs) following exposure to non-harmful visible light, leading to localized cell death. However, due to the complex topology of sensitive organs in the peritoneum, diffuse intra-abdominal PDT induces dose-limiting toxicities due to non-selective accumulation of PSs in both healthy and diseased tissue. In an effort to achieve selective damage to tumorous nodules, targeted PS formulations have shown promise to make PDT a feasible treatment modality in this setting. This targeted strategy involves chemical conjugation of PSs to antibodies, referred to as photoimmunoconjugates (PICs), to target OvCa specific molecular markers leading to enhanced therapeutic outcomes while reducing off-target toxicity. In light of promising results of pilot clinical studies and recent preclinical advances, this review provides the rationale and methodologies for PIC-based PDT, or photo-immunotherapy (PIT), in the context of OvCa management.

Biallelic ERBB3 loss-of-function variants are associated with a novel multisystem syndrome without congenital contracture

Background

Gain-of-function pathogenic variants of the Erb-B2 receptor tyrosine kinase 3 (ERBB3) gene contribute to the occurrence and development of a variety of human carcinomas through activation of phosphatidylinositol 3-kinase (PI3K)/AKT and extracellular signal-regulated kinase (ERK) signaling. ERBB3 gene homozygous germline variants, whose loss of function may cause autosomal recessive congenital contractural syndrome, were recently identified. This study aims to identify the disease-causing gene in a Chinese pedigree with variable phenotypes involving multiple systems, including developmental delay, postnatal growth retardation, transient lower limb asymmetry, facial malformations, atrioventricular canal malformation, bilateral nystagmus and amblyopia, feeding difficulties, immunodeficiency, anemia, and liver damage, but without congenital contracture.

Methods

Trio-whole exome sequencing (WES) was performed to identify the disease-causing gene in a 24-month-old Chinese female patient. The pathogenicity of the identified variants was evaluated using in silico tools and in vitro functional studies.

Results

Trio-WES revealed compound heterozygous variants of c.1253 T > C (p.I418T) and c.3182dupA (p.N1061Kfs*16) in the ERBB3 gene. Functional studies showed that p.I418T resulted in normal expression of ERBB3, which was capable of interacting with ERBB2. However, the variant impaired ERBB3 phosphorylation, consequently blocking ERBB2 phosphorylation and AKT and ERK activation. The truncated protein resulting from the c.3182dupA variant also lacked the capacity to activate downstream signaling pathways.

Conclusions

We report the first patient with a novel multisystem syndrome disorder without congenital contracture resulting from biallelic loss-of-function variants of ERBB3.

Phage display screening of therapeutic peptide for cancer targeting and therapy

Recently, phage display technology has been announced as the recipient of Nobel Prize in Chemistry 2018. Phage display technique allows high affinity target-binding peptides to be selected from a complex mixture pool of billions of displayed peptides on phage in a combinatorial library and could be further enriched through the biopanning process; proving to be a powerful technique in the screening of peptide with high affinity and selectivity. In this review, we will first discuss the modifications in phage display techniques used to isolate various cancer-specific ligands by in situ, in vitro, in vivo, and ex vivo screening methods. We will then discuss prominent examples of solid tumor targeting-peptides; namely peptide targeting tumor vasculature, tumor microenvironment (TME) and over-expressed receptors on cancer cells identified through phage display screening. We will also discuss the current challenges and future outlook for targeting peptide-based therapeutics in the clinics.

Efficacy and safety of HER2 inhibitors in combination with or without pertuzumab for HER2-positive breast cancer: a systematic review and meta-analysis

BACKGROUND

Although the dual anti-HER2 therapy, namely, pertuzumab plus trastuzumab and docetaxel, has shown promising results in HER2+ breast cancer patients, whether the dose, efficacy and safety of this treatment differs from those of other pertuzumab-based dual anti-HER2 therapies remain controversial. This systematic review evaluates the efficacy and safety of H (trastuzumab or trastuzumab emtansine ± chemotherapy) + P (pertuzumab) compared with those of H in HER2+ breast cancer patients.

METHODS

A comprehensive search was performed to identify eligible studies comparing the efficacy and safety of H + P versus H. The pathologic complete response (pCR), median progression-free survival (PFS) and overall survival (OS) were the primary outcomes, and safety was the secondary outcome. A subgroup analysis of pCR according to hormone receptor (HR) status was performed. All analyses were conducted using STATA 11.0.

RESULTS

Twenty-six studies (9872 patients) were identified. In the neoadjuvant setting, H + P significantly improved the pCR [odds ratio (OR) = 1.33; 95% confidence interval (CI), 1.08-1.63; p = 0.006]. In the metastatic setting, H + P significantly improved PFS [hazard ratios (HRs) = 0.75; 95% CI, 0.68-0.84; p < 0.001]. There was a trend towards better OS but that it did not reach statistical significance (HRs = 0.81; 95% CI, 0.64-1.03; p = 0.082). A subgroup analysis revealed that the HER2+/HR- patients who received H + P showed the highest increase in the pCR. Rash, diarrhea, epistaxis, mucosal inflammation, and anemia were significantly more frequently observed with H + P than with H, whereas myalgia was less frequent (OR = 0.91; 95% CI, 0.82-1.01; p = 0.072), and no significant difference in cardiac toxicity was observed between these therapies (OR = 1.26; 95% CI, 0.81-1.95; P = 0.309).

CONCLUSIONS

Our study confirms that H + P is superior to H in the (neo)adjuvant treatment of HER2+ breast cancer, and increase the risk of acceptable and tolerable toxicity (rash, diarrhea, epistaxis, mucosal inflammation, and anemia).

TRIAL REGISTRATION

A systematic review protocol was registered with PROSPERO (identification number: CRD42018110415 ).

Actinomycin V Suppresses Human Non-Small-Cell Lung Carcinoma A549 Cells by Inducing G2/M Phase Arrest and Apoptosis via the p53-Dependent Pathway

Actinomycin V, extracted and separated from marine-derived actinomycete Streptomyces sp., as the superior potential replacement of actinomycin D (which showed defect for its hepatotoxicity) has revealed an ideal effect in the suppression of migration and invasion in human breast cancer cells as referred to in our previous study. In this study, the involvement of p53 in the cell cycle arrest and pro-apoptotic action of actinomycin V was investigated in human non-small-cell lung carcinoma A549 cells. Results from the 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide assay showed that cytotoxic activity of actinomycin V on A549 cells (with wild-type p53) was stronger than the NCI-H1299 cells (p53-deficient). Actinomycin V upregulated both of the protein and mRNA expression levels of p53, p21Waf1/Cip1 and Bax in A549 cells. For this situation, actinomycin V decreased the M-phase related proteins (Cdc2, Cdc25A and Cyclin B1) expression, arrested cells in G2/M phase and subsequently triggered apoptosis by mediating the Bcl-2 family proteins' expression (Bax and Bcl-2). Furthermore, the effects of cell cycle arrest and apoptosis in A549 cells which were induced by actinomycin V could be reversed by the pifithrin-α, a specific inhibitor of p53 transcriptional activity. Collectively, our results suggest that actinomycin V causes up-regulation of p53 by which the growth of A549 cells is suppressed for cell cycle arrest and apoptosis.

ABC Transporter-Mediated Multidrug-Resistant Cancer

ATP-binding cassette (ABC) transporters are involved in active pumping of many diverse substrates through the cellular membrane. The transport mediated by these proteins modulates the pharmacokinetics of many drugs and xenobiotics. These transporters are involved in the pathogenesis of several human diseases. The overexpression of certain transporters by cancer cells has been identified as a key factor in the development of resistance to chemotherapeutic agents. In this chapter, the localization of ABC transporters in the human body, their physiological roles, and their roles in the development of multidrug resistance (MDR) are reviewed. Specifically, P-glycoprotein (P-GP), multidrug resistance-associated proteins (MRPs), and breast cancer resistance protein (BCRP/ABCG2) are described in more detail. The potential of ABC transporters as therapeutic targets to overcome MDR and strategies for this purpose are discussed as well as various explanations for the lack of efficacy of ABC drug transporter inhibitors to increase the efficiency of chemotherapy.

Metal-based antibody drug conjugates. Potential and challenges in their application as targeted therapies in cancer

Antibody drug conjugates have emerged as a very attractive type of targeted therapy in cancer. They combine the antigen-targeting specificity of monoclonal antibodies (mAbs) with the cytotoxic potency of chemotherapeutics. This review focuses on antibody drug conjugates based on metal-containing cytotoxic payloads. We will also describe antibody drug conjugates (ADCs) in which a metal-based component (mostly metallic nanoparticles) exerts a relevant function in the ADC (for photodynamic or photothermal therapy, as air-plasma-enhancer or chemo-sensitizer, as carrier of other cytotoxic payloads or as an integral part of the linker structure). Challenges and opportunities to increase the translational potential of these ADCs will be discussed.

Natural and engineered bacterial outer membrane vesicles

Bacterial outer membrane vesicle (OMV) is a kind of spherical lipid bilayer nanostructure naturally secreted by bacteria, which has diverse functions such as intracellular and extracellular communication, horizontal gene transfer, transfer of contents to host cells, and eliciting an immune response in host cells. In this review, several methods including ultracentrifugation and precipitation for isolating OMVs were summarized. The latest progresses of OMVs in biomedical fields, especially in vaccine development, cancer treatment, infection control, and bioimaging and detection were also summarized in this review. We highlighted the importance of genetic engineering for the safe and effective application and in facilitating the rapid development of OMVs. Finally, we discussed the bottleneck problems about OMVs in preparation and application at present and put forward our own suggestions about them. Some perspectives of OMVs in biomedical field were also provided.

Emerging therapeutic agents for genitourinary cancers

The treatment of genitourinary malignancies has dramatically evolved over recent years. Renal cell carcinoma, urothelial carcinoma of the bladder, and prostate adenocarcinoma are the most commonly encountered genitourinary malignancies and represent a heterogeneous population of cancers, in both histology and approach to treatment. However, all three cancers have undergone paradigm shifts in their respective therapeutic landscapes due to a greater understanding of their underlying molecular mechanisms and oncogenic drivers. The advance that has gained the most recent traction has been the advent of immunotherapies, particularly immune checkpoint inhibitors. Immunotherapy has increased overall survival and even provided durable responses in the metastatic setting in some patients. The early success of immune checkpoint inhibitors has led to further drug development with the emergence of novel agents which modulate the immune system within the tumor microenvironment. Notwithstanding immunotherapy, investigators are also developing novel agents tailored to a variety of targets including small-molecule tyrosine kinase inhibitors, mTOR inhibitors, and novel fusion proteins to name a few. Erdafitinib has become the first targeted therapy approved for metastatic bladder cancer. Moreover, the combination therapy of immune checkpoint inhibitors with targeted agents such as pembrolizumab or avelumab with axitinib has demonstrated both safety and efficacy and just received FDA approval for their use. We are in an era of rapid progression in drug development with multiple exciting trials and ongoing pre-clinical studies. We highlight many of the promising new emerging therapies that will likely continue to improve outcomes in patients with genitourinary malignancies.

A Novel HER3-Targeting Antibody-Drug Conjugate, U3-1402, Exhibits Potent Therapeutic Efficacy through the Delivery of Cytotoxic Payload by Efficient Internalization

PURPOSE

HER3 is a compelling target for cancer treatment; however, no HER3-targeted therapy is currently clinically available. Here, we produced U3-1402, an anti-HER3 antibody-drug conjugate with a topoisomerase I inhibitor exatecan derivative (DXd), and systematically investigated its targeted drug delivery potential and antitumor activity in preclinical models.

EXPERIMENTAL DESIGN

In vitro pharmacologic activities and the mechanisms of action of U3-1402 were assessed in several human cancer cell lines. Antitumor activity of U3-1402 was evaluated in xenograft mouse models, including patient-derived xenograft (PDX) models. Safety assessments were also conducted in rats and monkeys.

RESULTS

U3-1402 showed HER3-specific binding followed by highly efficient cancer cell internalization. Subsequently, U3-1402 was translocated to the lysosome and released its payload DXd. While U3-1402 was able to inhibit HER3-activated signaling similar to its naked antibody patritumab, the cytotoxic activity of U3-1402 in HER3-expressing cells was predominantly mediated by released DXd through DNA damage and apoptosis induction. In xenograft mouse models, U3-1402 exhibited dose-dependent and HER3-dependent antitumor activity. Furthermore, U3-1402 exerted potent antitumor activity against PDX tumors with HER3 expression. Acceptable toxicity was noted in both rats and monkeys.

CONCLUSIONS

U3-1402 demonstrated promising antitumor activity against HER3-expressing tumors with tolerable safety profiles. The activity of U3-1402 was driven by HER3-mediated payload delivery via high internalization into tumor cells.

Convergent synthesis of hydrophilic monomethyl dolastatin 10 based drug linkers for antibody-drug conjugation

We report a modular approach to synthesize maleimido group containing hydrophilic dolastatin 10 (Dol10) derivatives as drug-linkers for the syntheses of antibody-drug conjugates (ADCs). Discrete polyethylene glycol (PEG) moieties of different chain lengths were introduced as part of the linker to impart hydrophilicity to these drug linkers. The synthesis process involved construction of PEG maleimido derivatives of the tetrapeptide intermediate (N-methylvaline-valine-dolaisoleucine-dolaproine), which were subsequently coupled with dolaphenine to generate the desired drug linkers. The synthetic method reported in this manuscript circumvents the use of highly cytotoxic Dol10 in its native form. By using trastuzumab (Herceptin®) as the antibody we have synthesized Dol10 containing ADCs. The presence of a discrete PEG chain in the drug linkers resulted in ADCs free from aggregation. The effect of PEG chain length on the biological activities of these Dol10 containing ADCs was investigated by in vitro cytotoxicity assays. ADCs containing PEG₆ and PEG₈ spacers exhibited the highest level of in vitro anti-proliferative activity against HER2-positive (SK-BR-3) human tumor cells. ADCs derived from Herceptin® and PEG₈-Dol10, at a dose of 10 mg kg^-1, effectively delayed the tumor growth and prolonged the survival time in mice bearing human ovarian SKOV-3 xenografts.

MicroRNA-326 Functions as a Tumor Suppressor in Breast Cancer by Targeting ErbB/PI3K Signaling Pathway

Breast cancer represents the most common malignancy in women worldwide and the ErbB/PI3K pathway has been found to play a crucial role in regulation of the cancer cell growth. MicroRNAs have been implicated in regulating diverse cellular pathways and therefore, understanding the link between the regulatory microRNAs and the ErbB/PI3K signaling pathway could potentially be helpful for breast cancer prevention and treatment. The aim of this study is to examine the regulatory effect of miR-326 on ErbB/PI3K signaling pathway in breast cancer development and progression. The results of qRT-PCR, RNA seq, and array data indicated that miR-326 was remarkably down-regulated in breast tumor tissues and correlated with poor survival outcome. Importantly, very low levels of miR-326 expression were found in aggressive breast cells compared to less-aggressive cell types. Mechanistically, a gene network including EGFR, ErbB2, ErbB3, AKT1, AKT2, and AKT3 targeted by miR-326, thereby providing suppression of ErbB/PI3K pathway, detected by RT-qPCR, and dual luciferase assay. In addition, Western blot analysis revealed that miR-326 upregulation decreased PI3K signaling activity by decreasing total AKT and p-AKT protein level in SKBR3 cell lines. Interestingly, up regulation of ErbB2 rescued the effect of miR-326 on miR-326 target genes. Further functional assays demonstrated that up regulation of miR-326 significantly suppressed cell growth as evidenced by cell cycle, cell cycle associated genes expression, colony formation and MTT assays and induced apoptosis, detected by Annexin V-PI. In addition, EMT markers RT-qPCR, scratch, and Transwell assays showed inhibited cellular migration and invasion following miR-326 upregulation. Altogether, our results revealed that miR-326 play a tumor-suppressive role in breast cancer through inhibiting ErbB/PI3K pathway and miR-326 may serve as a potential therapeutic target for the treatment of patients with breast cancer.

Multiplex plasma protein profiling identifies novel markers to discriminate patients with adenocarcinoma of the lung

Background

The overall prognosis of non-small cell lung cancer (NSCLC) is poor, and currently only patients with localized disease are potentially curable. Therefore, preferably non-invasively determined biomarkers that detect NSCLC patients at early stages of the disease are of high clinical relevance. The aim of this study was to identify and validate novel protein markers in plasma using the highly sensitive DNA-assisted multiplex proximity extension assay (PEA) to discriminate NSCLC from other lung diseases.

Methods

Plasma samples were collected from a total of 343 patients who underwent surgical resection for different lung diseases, including 144 patients with lung adenocarcinoma (LAC), 68 patients with non-malignant lung disease, 83 patients with lung metastasis of colorectal cancers and 48 patients with typical carcinoid. One microliter of plasma was analyzed using PEA, allowing detection and quantification of 92 established cancer related proteins. The concentrations of the plasma proteins were compared between disease groups.

Results

The comparison between LAC and benign samples revealed significantly different plasma levels for four proteins; CXCL17, CEACAM5, VEGFR2 and ERBB3 (adjusted p-value < 0.05). A multi-parameter classifier was developed to discriminate between samples from LAC patients and from patients with non-malignant lung conditions. With a bootstrap aggregated decision tree algorithm (TreeBagger), a sensitivity of 93% and specificity of 64% was achieved to detect LAC in this risk population.

Conclusions

By applying the highly sensitive PEA, reliable protein profiles could be determined in microliter amounts of plasma. We further identified proteins that demonstrated different plasma concentration in defined disease groups and developed a signature that holds potential to be included in a screening assay for early lung cancer detection.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5943-3) contains supplementary material, which is available to authorized users.

Biomarker analysis of the GATSBY study of trastuzumab emtansine versus a taxane in previously treated HER2-positive advanced gastric/gastroesophageal junction cancer

BACKGROUND

Prespecified exploratory biomarker analyses of the phase II/III GATSBY study (NCT01641939) assessed whether patient subgroups experienced a survival benefit from trastuzumab emtansine (T-DM1) versus taxane therapy, and to advance understanding of HER2-positive advanced gastric/gastroesophageal junction cancer (AGC) disease biology.

METHODS

Adults with HER2-positive AGC whose disease progressed during/after first-line therapy were enrolled and randomized to receive T-DM1 [Stage 1: 3.6 mg/kg q3w, 2.4 mg/kg qw, or taxane (docetaxel/paclitaxel); Stage 2: 2.4 mg/kg qw or taxane]. Primary efficacy endpoint was overall survival (OS). Prespecified exploratory biomarkers included HER2, HER3, PTEN, PIK3CA mutation status, FcγR, and cMET. Tumor samples from patients who received 2.4 mg/kg T-DM1 (n = 228) or taxane (n = 117) were included.

RESULTS

Median OS was longer in subgroups with HER2 immunohistochemistry (IHC) 3+ [9.5 versus 8.3 months for T-DM1 versus taxane; hazard ratio (HR) 0.99 (95% CI 0.68-1.43)] versus HER2 IHC 2+/in situ hybridization-positive [5.2 versus 9.2 months for T-DM1 versus taxane; HR 1.53 (95% CI 0.94-2.50)] tumors. Trends towards increased median OS were also observed in subgroups with > versus ≤ median HER2 mRNA expression, higher versus lower HER2 gene copy number, HER2 gene ratio and H score, and homogenous or nonfocal HER2 IHC staining. T-DM1 was not associated with superior OS versus taxane in any subgroup.

CONCLUSIONS

Patients with previously treated HER2-positive AGC with higher HER2 expression experienced a better treatment effect from T-DM1 than those with lower HER2 expression and may derive comparable survival benefits from T-DM1 and taxane therapy.

CLINICAL TRIALS REGISTRATION

NCT01641939 ( https://clinicaltrials.gov/ct2/show/NCT01641939 ).

Inhibition of HER2-Positive Breast Cancer Growth by Blocking the HER2 Signaling Pathway with HER2-Glycan-Imprinted Nanoparticles

Blocking the HER2 signaling pathway has been an effective strategy in the treatment of HER2-positive breast cancer. It mainly relies on the use of monoclonal antibodies and tyrosine-kinase inhibitors. Herein, we present a new strategy, the nano molecularly imprinted polymer (nanoMIP). The nanoMIPs, imprinted using HER2 N-glycans, could bind almost all HER2 glycans and suppress the dimerization of HER2 with other HER family members, blocking the downstream signaling pathways, thereby inhibiting HER2+ breast cancer growth. In vitro experiments demonstrated that the nanoMIPs specifically targeted HER2+ cells and inhibited cell proliferation by 30 %. In vivo experiments indicated that the mean tumor volume of the nanoMIP-treated group was only about half of that of the non-treated groups. This study provides not only a new possibility to treat of HER2+ breast cancer but also new evidence to boost further development of nanoMIPs for cancer therapy.

HER3 targeting potentiates growth suppressive effects of the PI3K inhibitor BYL719 in pre-clinical models of head and neck squamous cell carcinoma

BYL719 is a PI3K inhibitor that has demonstrated efficacy in the treatment of head and neck squamous cell carcinoma. BYL719 exerts its therapeutic effect by suppressing AKT and other proliferative signaling mechanisms. Despite PI3K inhibition and AKT suppression, residual activity of protein S6, a core marker of proliferative activation, has been observed. HER3, either via dimerization or activation by its ligand neurgeulin (NRG), is known to activate PI3K. Thus, we hypothesized that co-targeting HER3 and PI3K would lead to greater suppression of the PI3K-AKT signaling pathway and greater tumor suppression than with BYL719 alone. We investigated biochemical expression and activation of the HER3-PI3K-AKT-S6 pathway in HNSCC cell lines and patient-derived xenografts (PDXs). Antitumor effects of HER3 and PI3K inhibitors alone and in combination were evaluated in cell culture and murine models. Treatment of HNSCC cell lines with BYL719 significantly reduced AKT activation and suppressed tumor growth. However, S6 was persistently activated despite suppression of AKT. Combination treatment with KTN3379, a monoclonal antibody targeted against HER3, and BYL719 led to enhanced suppression of in vitro and in vivo cancer growth and durable suppression of AKT and S6. Therefore, inhibition of HER3 with KTN3379 enhanced the effects of PI3K inhibition in pre-clinical HNSCC models. These data support co-targeting HER3 and PI3K for the treatment of HSNCC.

A Tribute to John Mendelsohn: A Pioneer in Targeted Cancer Therapy

Cancer scientists and clinicians are mourning the death of one of the most accomplished members of their community: Dr. John Mendelsohn. He was a pioneer in targeted cancer therapy and was instrumental for the discovery and deployment of the first antagonist epidermal growth factor receptor (EGFR) therapeutic antibodies, broadening the concept of targeted EGFR therapy to encompass other receptor tyrosine kinases, such as HER2, and developing blocking antibody-combination therapy with chemotherapies or radiotherapy. Dr. Mendelsohn, who died on January 7, 2019, always led by the strength of his accomplishments and the humility of his character. Above all, he was a well-revered mentor and clinician, who extended compassion and the gift of his time to patients, colleagues, and mentees alike. In tribute to Dr. Mendelsohn, Cancer Research has invited his former mentees and colleagues who were associated with Dr. Mendelsohn for over three decades to reflect on the broad impact of his work. Here, we discuss Dr. Mendelsohn's illustrious career at three elite academic cancer institutions and hospitals in the United States, his acumen to build, grow, and uplift institutions, and train a generation of medical oncologists, physician scientists, and cancer biologists. His profound legacy on targeted therapy and cancer research and treatment continue to prolong and save the lives of cancer patients globally.

Dasatinib inhibition of cSRC prevents the migration and metastasis of canine mammary cancer cells with enhanced Wnt and HER signalling

Human epidermal growth factor 2 (HER2) overexpression leads to aggressive mammary tumour growth. Although the prognosis of HER2⁺ tumours in humans is greatly improved using biologicals, therapy resistance, which may be caused by increased phosphatidyl-3-kinase (PI3K), rous sarcoma proto-oncogene (cSRC) or wingless-type MMTV integration site family (Wnt) activity, is a major concern. A recent analysis of 12 canine mammary cell lines showed an association between HER2/3 overexpression and phosphatase and tensin homologue (PTEN) deletion with elevated Wnt-signalling. Wnt-activity appeared to be insensitive to phosphatidyl-3-kinase (PI3K) inhibitors but sensitive to Src-I1. We hypothesized that Wnt activation, was caused by HER2/3-activated cSRC activation. The role of HER2/3 on Wnt signalling was investigated by silencing HER2/3 expression using specific small interfering RNA (siRNAs). Next, the effect of an epidermal growth factor receptor (EGFR)/HER2 tyrosine kinase inhibitor on Wnt activity and migration was investigated and compared to other tyrosine kinase inhibitors (TKIs) of related signalling pathways. Finally, two TKIs, a cSRC and a PI3K inhibitor, were investigated in a zebrafish xenograft model. Silencing of HER1-3 did not inhibit the intrinsic high Wnt activity, whereas the HER kinase inhibitor afatinib showed enhanced Wnt activity. The strongest inhibition of Wnt activity and cell viability and migration was shown by cSRC inhibitors, which also showed strong inhibition of cell viability and metastasis in a zebrafish xenograft model. HER2/3 overexpression or HER2/3-induced cSRC activation is not the cause of enhanced Wnt activity. However, inhibition of cSRC resulted in a strong inhibition of Wnt activity and cell migration and metastasis. Further studies are needed to unravel the mechanism of cSRC activation and cSRC inhibition to restore sensitivity to HER-inhibitors in HER2/3-positive breast cancer.