Epidermal growth factor receptor expression affects proliferation and apoptosis in non-small cell lung cancer cells via the extracellular signal-regulated kinase/microRNA 200a signaling pathway

Effect of PTFGRN Expression on the Proteomic Profile of A431 Cells and Determination of the PTGFRN Interactome

Prostaglandin F2 receptor negative regulator (PTGFRN) is a transmembrane protein whose expression has been previously implicated in cancer metastasis. However, the exact molecular mechanisms by which PTGFRN influences cancer progression are still unknown. As such, our laboratory set out to investigate how PTGFRN knockdown affected the expression of other proteins. We also carried out coimmunoprecipitation experiments using a monoclonal anti-PTGFRN antibody. We employed mass spectrometry-based proteomics for both experiments to identify proteins that were associated with PTGFRN. Our data show that PTGFRN knockdown increased pathways related to innate immune responses and decreased pathways associated with the synthesis of metabolic precursors and protein processing, among others. Additionally, the coimmunoprecipitation experiments indicated that PTGFRN is associated with proteins involved in processing and metabolism, as well as VEGF signaling molecules. These results highlight the role of PTGFRN as a protein processing regulator, which may be influencing cancer progression.

Oncolytic herpes simplex viruses designed for targeted treatment of EGFR-bearing tumors

Oncolytic herpes simplex viruses (oHSVs) have emerged as leading cancer therapeutic agents. Effective oHSV virotherapy may ultimately require both intratumoral and systemic vector administration to target the primary tumor and distant metastases. An attractive approach to enhancing oHSV tumor specificity is engineering the virus envelope glycoproteins for selective recognition of and infection via tumor-specific cell surface proteins. We previously demonstrated that oHSVs could be retargeted to EGFR-expressing cells by the incorporation of a single-chain antibody (scFv) at the N terminus of glycoprotein D (gD). Here, we compared retargeted oHSVs generated by the insertion of scFv, affibody molecule, or VHH antibody ligands at different positions within the N terminus of gD. When compared to the scFv-directed oHSVs, VHH and affibody molecules mediated enhanced EGFR-specific tumor cell entry, spread and cell killing in vitro, and enabled long-term tumor-specific virus replication following intravenous delivery in vivo. Moreover, oHSVs retargeted via a VHH ligand reduced tumor growth upon intravenous injection and achieved complete tumor destruction after intratumoral injection. Systemic oHSV delivery is important for the treatment of metastatic disease, and our enhancements in targeted oHSV design are a critical step in creating an effective tumor-specific oHSVs for safe administration via the bloodstream.

Profiling of ERBB receptors and downstream pathways reveals selectivity and hidden properties of ERBB4 antagonists

ERBB receptor tyrosine kinases are involved in development and diseases like cancer, cardiovascular, neurodevelopmental, and mental disorders. Although existing drugs target ERBB receptors, the next generation of drugs requires enhanced selectivity and understanding of physiological pathway responses to improve efficiency and reduce side effects. To address this, we developed a multilevel barcoded reporter profiling assay, termed 'ERBBprofiler', in living cells to monitor the activity of all ERBB targets and key physiological pathways simultaneously. This assay helps differentiate on-target therapeutic effects from off-target and off-pathway side effects of ERBB antagonists. To challenge the assay, eight established ERBB antagonists were profiled. Known effects were confirmed, and previously uncharacterized properties were discovered, such as pyrotinib's preference for ERBB4 over EGFR. Additionally, two lead compounds selectively targeting ERBB4 were profiled, showing promise for clinical trials. Taken together, this multiparametric profiling approach can guide early-stage drug development and lead to improved future therapeutic interventions.

Identification of the Brucea javanica Constituent Brusatol as a EGFR-Tyrosine Kinase Inhibitor in a Cell-Free Assay

Inhibitors of the tyrosine kinase (TK) activity of the epidermal growth factor receptor (EGFR) are routinely used in cancer therapy. However, there is a need to discover a new TK inhibitor. This study evaluated extracts from Brucea javanica and its components for their potential as novel EGFR-TK inhibitors. The cytotoxic effect of a g aqueous extract and its fractions was assessed by MTT assays with A549 lung cancer cells. The two fractions with the highest cytotoxicity were analyzed by LC/MS and 1H NMR. Brusatol was identified as the main constituent of these fractions, and its cytotoxic and pro-apoptotic activities were confirmed in A549 cells. To elucidate the inhibitory activity of brusatol against EGFR-TK, a specific ADP-GloTM kinase assay was used. In this assay, the IC50 value for EGFR-TK inhibition was 333.1 nM. Molecular dynamic simulations and docking experiments were performed to identify the binding pocket of brusatol to be located in the intracellular TK-domain of EGFR. This study demonstrates that brusatol inhibits EGFR-TK and therefore harbors a potential as a new therapeutic drug for the therapy of EGFR-depending cancers.

Spatial Control of Receptor Dimerization Using Programmable DNA Nanobridge

Receptor dimerization is an essential mechanism for the activation of most receptor tyrosine kinases by ligands. Thus, regulating the nanoscale spatial distribution of cell surface receptors is significant for studying both intracellular signaling pathways and cellular behavior. However, there are currently very limited methods for exploring the effects of modulating the spatial distribution of receptors on their function by using simple tools. Herein, we developed an aptamer-based double-stranded DNA bridge acting as "DNA nanobridge", which regulates receptor dimerization by changing the number of bases. On this basis, we confirmed that the different nanoscale arrangements of the receptor can influence receptor function and its downstream signals. Among them, the effect gradually changed from helping to activate to inhibiting as the length of DNA nanobridge increased. Hence, it can not only effectively inhibit receptor function and thus affect cellular behavior but also serve as a fine-tuning tool to get the desired signal activity. Our strategy is promising to provide insight into the action of receptors in cell biology from the perspective of spatial distribution.

Synthesis, Radiolabeling, and In Vitro and In Vivo Characterization of Heterobivalent Peptidic Agents for Bispecific EGFR and Integrin αvβ3 Targeting

Radiolabeled heterobivalent peptidic ligands (HBPLs) are a highly promising compound class for the sensitive and specific visualization of tumors as they often exhibit superior properties compared to their monospecific counterparts and are able to concomitantly or complementarily address different receptor types. The combination of two receptor-specific agents targeting the epidermal growth factor receptor (EGFR) and the integrin α_vβ₃ in one HBPL would constitute a synergistic combination of binding motifs as these two receptor types are concurrently overexpressed on several human tumor types and are closely associated with disease progression and metastasis. Here, we designed and synthesized two heterobivalent radioligands consisting of the EGFR-specific peptide GE11 and α_vβ₃-specific cyclic RGD peptides, bearing a (1,4,7-triazacyclononane-4,7-diyl)diacetic acid-1-glutaric acid chelator for efficient radiolabeling and linkers of different lengths between both peptides. Both HBPLs were radiolabeled with ⁶⁸Ga³⁺ in high radiochemical yields, purities of 96-99%, and molar activities of 36-88 GBq/μmol. [⁶⁸Ga]Ga-1 and [⁶⁸Ga]Ga-2 were evaluated for their log _D(7.4) and stability toward degradation by human serum peptidases, showing a high hydrophilicity for both agents of -3.07 ± 0.01 and -3.44 ± 0.08 as well as a high stability toward peptidase degradation in human serum with half-lives of 272 and 237 min, respectively. Further on, the in vitro receptor binding profiles of both HBPLs to the target EGF and integrin α_vβ₃ receptors were assessed on EGFR-positive A431 and α_vβ₃-positive U87MG cells. Finally, we investigated the in vivo pharmacokinetics of HBPL [⁶⁸Ga]Ga-1 by positron emission tomography/computed tomography imaging in A431 tumor-bearing xenograft mice to assess its potential for the receptor-specific visualization of EGFR- and/or α_vβ₃-expressing tumors. In these experiments, [⁶⁸Ga]Ga-1 demonstrated a tumor uptake of 2.79 ± 1.66% ID/g, being higher than in all other organs and tissues apart from kidneys and blood at 2 h p.i. Receptor blocking studies revealed the observed tumor uptake to be solely mediated by integrin α_vβ₃, whereas no contribution of the GE11 peptide sequence to tumor uptake via the EGFR could be determined. Thus, the approach to develop radiolabeled EGFR- and integrin α_vβ₃-bispecific HBPLs is in general feasible although another peptide lead structure than GE11 should be used as the basis for the EGFR-specific part of the agents.

Novel 2-(5-Aryl-4,5-Dihydropyrazol-1-yl)thiazol-4-One as EGFR Inhibitors: Synthesis, Biological Assessment and Molecular Docking Insights

Introduction

Epidermal growth factor receptor (EGFR) regulates several cell functions which include cell growth, survival, multiplication, differentiation, and apoptosis. Currently, EGFR kinase inhibitors are of increasing interest as promising targeted antitumor therapeutic agents.

Methods

Different thiazolyl-pyrazoline derivatives (7a-o) were synthesized and were first tested for anti-proliferative effect towards the A549 lung cancer cell line and the T-47D breast cancer cell line in MTT assay. Thereafter, thiazolyl-pyrazolines (7b, 7g, 7l, and 7m) were subsequently evaluated for their PK inhibition for EGFR. Moreover, representative promising derivatives (7g and 7m) in cytotoxic and PK inhibition assays were tested to investigate their impact on the apoptosis and cell cycle phases in T-47D cells in order to explore more insights into the antitumor actions of the target thiazolyl-pyrazolines. Furthermore, docking studies were accomplished to evaluate the patterns of binding of thiazolyl-pyrazolines 7b, 7g, 7l, and 7m in the EGFR active pocket (PDB ID: 1M17).

Results

Testing the thiazolyl pyrazoline compounds 7a-o on A549 and T-47D cell lines showed IC₅₀ arrays between 3.92 and 89.03 µM, and between 0.75 and 77.10 µM, respectively. Also, the tested thiazolyl-pyrazolines (7b, 7g, 7l, and 7m) demonstrated significant sub-micromolar EGFR inhibitory actions with IC₅₀ values 83, 262, 171 and 305 nM, respectively, in comparison to erlotinib (IC₅₀ =57 nM).

Discussion

Generally, it was observed that the tested thiazolyl pyrazolines showed more potent antiproliferative activity toward breast cancer cells T-47D than toward lung cancer cell lines A549. In particular, thiazolyl pyrazolines 7g and 7m showed the best activity against A549 cells (IC₅₀ = 3.92 and 6.53 µM) and T-47D cells (IC₅₀ = 0.88 and 0.75 µM). Compounds 7g and 7m provoked a sub-G1 phase arrest and cell apoptosis which are in agreement with the expected outcome of EGFR inhibition. Finally, the molecular docking of 7g and 7m in the active site of EGFR revealed a common binding pattern similar to that of erlotinib which involves the accommodation of the 1,3 thiazol-4-one ring and pyrazoline ring of target compounds in the binding region of erlotinib’s quinazoline ring and anilino moiety.

Re-Expression of Poly/Oligo-Sialylated Adhesion Molecules on the Surface of Tumor Cells Disrupts Their Interaction with Immune-Effector Cells and Contributes to Pathophysiological Immune Escape

Glycans linked to surface proteins are the most complex biological macromolecules that play an active role in various cellular mechanisms. This diversity is the basis of cell-cell interaction and communication, cell growth, cell migration, as well as co-stimulatory or inhibitory signaling. Our review describes the importance of neuraminic acid and its derivatives as recognition elements, which are located at the outermost positions of carbohydrate chains linked to specific glycoproteins or glycolipids. Tumor cells, especially from solid tumors, mask themselves by re-expression of hypersialylated neural cell adhesion molecule (NCAM), neuropilin-2 (NRP-2), or synaptic cell adhesion molecule 1 (SynCAM 1) in order to protect themselves against the cytotoxic attack of the also highly sialylated immune effector cells. More particularly, we focus on α-2,8-linked polysialic acid chains, which characterize carrier glycoproteins such as NCAM, NRP-2, or SynCam-1. This characteristic property correlates with an aggressive clinical phenotype and endows them with multiple roles in biological processes that underlie all steps of cancer progression, including regulation of cell-cell and/or cell-extracellular matrix interactions, as well as increased proliferation, migration, reduced apoptosis rate of tumor cells, angiogenesis, and metastasis. Specifically, re-expression of poly/oligo-sialylated adhesion molecules on the surface of tumor cells disrupts their interaction with immune-effector cells and contributes to pathophysiological immune escape. Further, sialylated glycoproteins induce immunoregulatory cytokines and growth factors through interactions with sialic acid-binding immunoglobulin-like lectins. We describe the processes, which modulate the interaction between sialylated carrier glycoproteins and their ligands, and illustrate that sialic acids could be targets of novel therapeutic strategies for treatment of cancer and immune diseases.

Using Chitosan or Chitosan Derivatives in Cancer Therapy

Cancer is one of the major causes of death worldwide. Chemotherapeutic drugs have become a popular choice as anticancer agents. Despite the therapeutic benefits of chemotherapeutic drugs, patients often experience side effects and drug resistance. Biopolymers could be used to overcome some of the limitations of chemotherapeutic drugs, as well as be used either as anticancer agents or drug delivery vehicles. Chitosan is a biocompatible polymer derived from chitin. Chitosan, chitosan derivatives, or chitosan nanoparticles have shown their promise as an anticancer agent. Additionally, functionally modified chitosan can be used to deliver nucleic acids, chemotherapeutic drugs, and anticancer agents. More importantly, chitosan-based drug delivery systems improved the efficacy, potency, cytotoxicity, or biocompatibility of these anticancer agents. In this review, we will investigate the properties of chitosan and chemically tuned chitosan derivatives, and their application in cancer therapy.

Covalent N-arylation by the pollutant 1,2-naphthoquinone activates the EGF receptor

The epidermal growth factor receptor (EGFR) is the most intensively investigated receptor tyrosine kinase. Several EGFR mutations and modifications have been shown to lead to abnormal self-activation, which plays a critical role in carcinogenesis. Environmental air pollutants, which are associated with cancer and respiratory diseases, can also activate EGFR. Specifically, the environmental electrophile 1,2-naphthoquinone (1,2-NQ), a component of diesel exhaust particles and particulate matter more generally, has previously been shown to impact EGFR signaling. However, the detailed mechanism of 1,2-NQ function is unknown. Here, we demonstrate that 1,2-NQ is a novel chemical activator of EGFR but not other EGFR family proteins. We found that 1,2-NQ forms a covalent bond, in a reaction referred to as N-arylation, with Lys80, which is in the ligand-binding domain. This modification activates the EGFR-Akt signaling pathway, which inhibits serum deprivation-induced cell death in a human lung adenocarcinoma cell line. Our study reveals a novel mode of EGFR pathway activation and suggests a link between abnormal EGFR activation and environmental pollutant-associated diseases such as cancer.

Growth suppression of colorectal cancer expressing S492R EGFR by monoclonal antibody CH12

Colorectal cancer (CRC) is a common malignant tumor in the digestive tract, and 30%-85% of CRCs express epidermal growth factor receptors (EGFRs). Recently, treatments using cetuximab, also named C225, an anti-EGFR monoclonal antibody, for CRC have been demonstrated to cause an S492R mutation in EGFR. However, little is known about the biological function of S492R EGFR. Therefore, we attempted to elucidate its biological function in CRC cells and explore new treatment strategies for this mutant form. Our study indicated that EGFR and S492R EGFR accelerate the growth of CRC cells in vitro and in vivo and monoclonal antibody CH12, which specifically recognizes an EGFR tumor-specific epitope, can bind efficiently to S492R EGFR. Furthermore, mAb CH12 showed significantly stronger growth suppression activities and induced a more potent antibody-dependent cellular cytotoxicity effect on CRC cells bearing S492R EGFR than mAb C225. mAb CH12 obviously suppressed the growth of CRC xenografts with S492R EGFR mutations in vivo. Thus, mAb CH12 may be a promising therapeutic agent in treating patients with CRC bearing an S492R EGFR mutation.

MicroRNA-374b inhibits the tumor growth and promotes apoptosis in non-small cell lung cancer tissue through the p38/ERK signaling pathway by targeting JAM-2

Background

MicroRNAs (miRNAs) are reportedly involved in various cancers. The present study aimed to investigate the role of miRNA-374b in cell viability, proliferation, apoptosis, and tumor formation in non-small cell lung cancer (NSCLC) in humans.

Methods

The expression level of miRNA-374b in blood and tumor tissues from NSCLC patients was analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to assess the viability of NSCLC cells after transfection with miRNA-374b. Colony formation assay was performed to assess the proliferation of cells pretreated with miRNA-374b. The terminal deoxynucleotidyl transferase-dUTP nick-end labeling (TUNEL) assay was performed to determine the role of miRNA-374b in apoptosis in NSCLC cells. A tumor formation assay was performed to assess the effects of miRNA-374b on tumorigenesis in NSCLC.

Results

miRNA-374b was markedly downregulated in the blood and tumor tissues from NSCLC patients. Furthermore, overexpression of miRNA-374b markedly reduced the viability of NSCLC cells, but miRNA-374b inhibitor increased the viability of NSCLC cells compared with that in negative controls. Moreover, miRNA-374b decreased the number of colonies; however, its corresponding anti-miRNA oligonucleotide (AMO) markedly increased colony formation by NSCLC cells. Also, miRNA-374b promoted the apoptosis and inhibited tumor formation in NSCLC; however, this inhibition was reversed upon treatment with the AMO. Western blot analysis revealed that miRNA-374b regulates tumor progression through the p38/ERK signaling pathway by inhibiting JAM-2 in NSCLC.

Conclusions

The present results indicate that miRNA-374b inhibits tumor growth and promotes apoptosis in NSCLC through the p38/ERK signaling pathway by targeting JAM-2.