Oncogenic KRAS-induced epiregulin overexpression contributes to aggressive phenotype and is a promising therapeutic target in non-small-cell lung cancer

Coexisting Lung Cancer and Pulmonary Tuberculosis: A Comprehensive Review From Incidence to Management

BACKGROUND

Globally, infections account for 10% of new cancer cases, and cancer can compromise the immune system, increasing the risk of infections. With advances in cancer treatment, widespread use of immunotherapy, and prolonged survival of cancer patients, the coexistence of tuberculosis (TB) and cancer is becoming increasingly common in clinical settings.

AIM

This review aims to explore the interaction between tuberculosis (TB) and tumors, particularly lung cancer (LC), and to identify appropriate clinical management approaches.

RESULTS

LC patients with a history of TB have higher adjusted risk ratios for both all-cause and cancer-specific 3-year mortality compared to those without a history of TB. TB may elevate the risk of developing tumors through mechanisms such as chronic inflammation, altered immune responses, and DNA damage. Conversely, cancer patients, whether due to the disease itself or immune dysfunction caused by anti-tumor treatments, may be more susceptible to TB. The coexistence of TB and tumors presents significant challenges in clinical management, making the development of treatment strategies and quality-of-life improvements crucial.

CONCLUSION

There is a close relationship between TB and cancer, with TB potentially serving as a risk factor for cancer, and cancer influencing susceptibility to TB. Effective clinical management is essential to enhance treatment strategies and improve the quality of life for patients with both TB and cancer.

Antibody-Drug Conjugates Targeting the EGFR Ligand Epiregulin Elicit Robust Antitumor Activity in Colorectal Cancer

As colorectal cancer remains a leading cause of cancer-related death, identifying therapeutic targets and approaches is essential to improve patient outcomes. The EGFR ligand epiregulin (EREG) is highly expressed in RAS wild-type (WT) and mutant colorectal cancer, with minimal expression in normal tissues, making it an attractive target for antibody-drug conjugate (ADC) development. In this study, we produced and purified an EREG mAb, H231, which had high specificity and affinity for human and mouse EREG. H231 also internalized to lysosomes, which is important for ADC payload release. ImmunoPET and ex vivo biodistribution studies showed significant tumor uptake of zirconium-89-labeled H231, with minimal uptake in normal tissues. H231 was conjugated to either cleavable dipeptide or tripeptide chemical linkers attached to the DNA-alkylating payload duocarmycin DM, and the cytotoxicity of EREG ADCs was assessed in a panel of colorectal cancer cell lines. EREG ADCs incorporating tripeptide linkers demonstrated the highest potency in EREG-expressing colorectal cancer cells irrespective of RAS mutations. Preclinical safety and efficacy studies showed that EREG ADCs were well tolerated, neutralized EGFR pathway activity, caused significant tumor growth inhibition or regression, and increased survival in colorectal cancer cell line and patient-derived xenograft models. These data suggest that EREG is a promising target for the development of ADCs for treating colorectal cancer and other cancer types that express high levels of EREG. Although the efficacy of clinically approved anti-EGFR mAbs is largely limited by RAS mutational status, EREG ADCs may show promise for both RAS mutant and WT patients, thus improving existing treatment options. Significance: EREG-targeting antibody-drug conjugates demonstrate acceptable safety and robust therapeutic efficacy in RAS mutant and wild-type colorectal cancer, suggesting their potential as an alternative to EGFR-targeted therapy to benefit a broader patient population.

Non-Genotoxic and Environmentally Relevant Lower Molecular Weight Polycyclic Aromatic Hydrocarbons Significantly Increase Tumorigenicity of Benzo[a]pyrene in a Lung Two-Stage Mouse Model

The World Health Organization has classified air pollution as a carcinogen, and polycyclic aromatic hydrocarbons (PAHs) are major components of air particulates of carcinogenic concern. Thus far, most studies focused on genotoxic high molecular weight PAHs; however, recent studies indicate potential carcinogenicity of the non-genotoxic lower molecular weight PAHs (LMW PAHs) that are found in indoor and outdoor air pollution as well as secondhand cigarette smoke. We hypothesize that LMW PAHs contribute to the promotion stage of cancer when combined with benzo[a]pyrene (B[a]P), a legacy PAH. We specifically determined the effects of an LMW PAH mixture containing 1-methylanthracene (1MeA), fluoranthene (Flthn), and phenanthrene (Phe) combined with B[a]P on lung tumor promotion. To test this hypothesis, we used a two-stage, initiation/promotion BALB/ByJ female lung tumor mouse model. The mice were initiated with 3-methylcholanthrene followed by exposures to B[a]P, the LMW PAH mixture, and the combination of the LMW PAH mixture plus B[a]P, all at 10 mg/kg. The LMW PAHs combined with B[a]P significantly increased the promotion and incidence of lung tumors over that of B[a]P alone. The LMW PAHs in the absence of B[a]P did not significantly promote tumors, indicating strong co-promotional activities. We further assessed the effects of these PAHs on other hallmarks of cancer, namely, bronchoalveolar lavage fluid inflammatory infiltrates, pro-inflammatory transcripts, KC protein content, and mRNA expression of the gap junction (Gja1) and epiregulin (Ereg) genes. The LMW PAHs increased the biomarkers of inflammation, decreased Gja1 expression, and increased Ereg expression, all consistent with tumor promotion. This study indicates that non-genotoxic LMW PAHs can contribute to the cancer process and warrants further studies to assess the carcinogenic risks of other LMW PAHs.

Antibody-Drug Conjugates Targeting the EGFR Ligand Epiregulin Elicit Robust Anti-Tumor Activity in Colorectal Cancer

As colorectal cancer (CRC) remains a leading cause of cancer-related death, identifying therapeutic targets and approaches is essential to improve patient outcomes. The EGFR ligand epiregulin (EREG) is highly expressed in RAS wildtype and mutant CRC with minimal expression in normal tissues, making it an attractive target for antibody-drug conjugate (ADC) development. In this study, we produced and purified an EREG monoclonal antibody (mAb), H231, that had high specificity and affinity for human and mouse EREG. H231 also internalized to lysosomes, which is important for ADC payload release. ImmunoPET and ex vivo biodistribution studies showed significant tumor uptake of 89Zr-labeled H231 with minimal uptake in normal tissues. H231 was conjugated to either cleavable dipeptide or tripeptide chemical linkers attached to the DNA-alkylating payload duocarmycin DM, and cytotoxicity of EREG ADCs was assessed in a panel of CRC cell lines. EREG ADCs incorporating tripeptide linkers demonstrated the highest potency in EREG-expressing CRC cells irrespective of RAS mutations. Preclinical safety and efficacy studies showed EREG ADCs were well-tolerated, neutralized EGFR pathway activity, caused significant tumor growth inhibition or regression, and increased survival in CRC cell line and patient-derived xenograft models. These data suggest EREG is a promising target for the development of ADCs for treating CRC and other cancer types that express high levels of EREG. While the efficacy of clinically approved anti-EGFR mAbs are largely limited by RAS mutational status, EREG ADCs may show promise for both RAS mutant and wildtype patients, thus improving existing treatment options.

5'-Isoforms of miR-1246 Have Distinct Targets and Stronger Functional Impact Compared with Canonical miR-1246 in Colorectal Cancer Cells In Vitro

Colorectal cancer (CRC) is a multifactorial disease involving genetic and epigenetic factors, such as miRNAs. Sequencing-based studies have revealed that miRNAs have many isoforms (isomiRs) with modifications at the 3'- and 5'-ends or in the middle, resulting in distinct targetomes and, consequently, functions. In the present study, we aimed to evaluate the putative targets and functional role of miR-1246 and its two 5'-isoforms (ISO-miR-1246_a and ISO-miR-1246_G) in vitro. Commercial Caco-2 cells of CRC origin were analyzed for the expression of WT-miR-1246 and its 5'-isoforms using small RNA sequencing data, and the overabundance of the two miR-1246 isoforms was determined in cells. The transcriptome analysis of Caco-2 cells transfected with WT-miR-1246, ISO-miR-1246_G, and ISO-miR-1246_a indicated the minor overlap of the targetomes between the studied miRNA isoforms. Consequently, an enrichment analysis showed the involvement of the potential targets of the miR-1246 isoforms in distinct signaling pathways. Cancer-related pathways were predominantly more enriched in dysregulated genes in ISO-miR-1246_G and ISO-miR-1246_a, whereas cell cycle pathways were more enriched in WT-miR-1246. The functional analysis of WT-miR-1246 and its two 5'-isoforms revealed that the inhibition of any of these molecules had a tumor-suppressive role (reduced cell viability and migration and promotion of early cell apoptosis) in CRC cells. However, the 5'-isoforms had a stronger effect on viability compared with WT-miR-1246. To conclude, this research shows that WT-miR-1246 and its two 5'-isoforms have different targetomes and are involved in distinct signaling pathways but collectively play an important role in CRC pathogenesis.

Role of Epiregulin in Lung Tumorigenesis and Therapeutic Resistance

Epidermal growth factor (EGF) signaling regulates multiple cellular processes and plays an essential role in tumorigenesis. Epiregulin (EREG), a member of the EGF family, binds to the epidermal growth factor receptor (EGFR) and ErbB4, and it stimulates EGFR-related downstream pathways. Increasing evidence indicates that both the aberrant expression and oncogenic function of EREG play pivotal roles in tumor development in many human cancers, including non-small cell lung cancer (NSCLC). EREG overexpression is induced by activating mutations in the EGFR, KRAS, and BRAF and contributes to the aggressive phenotypes of NSCLC with oncogenic drivers. Recent studies have elucidated the roles of EREG in a tumor microenvironment, including the epithelial-mesenchymal transition, angiogenesis, immune evasion, and resistance to anticancer therapy. In this review, we summarized the current understanding of EREG as an oncogene and discussed its oncogenic role in lung tumorigenesis and therapeutic resistance.

A novel selective ERK1/2 inhibitor, Laxiflorin B, targets EGFR mutation subtypes in non-small-cell lung cancer

Extracellular regulated protein kinases 1/2 (ERK1/2) are key members of multiple signaling pathways, including the ErbB axis. Ectopic ERK1/2 activation contributes to various types of cancer, especially drug resistance to inhibitors of RTK, RAF and MEK, and specific ERK1/2 inhibitors are scarce. In this study, we identified a potential novel covalent ERK inhibitor, Laxiflorin B, which is a herbal compound with anticancer activity. However, Laxiflorin B is present at low levels in herbs; therefore, we adopted a semi-synthetic process for the efficient production of Laxiflorin B to improve the yield. Laxiflorin B induced mitochondria-mediated apoptosis via BAD activation in non-small-cell lung cancer (NSCLC) cells, especially in EGFR mutant subtypes. Transcriptomic analysis suggested that Laxiflorin B inhibits amphiregulin (AREG) and epiregulin (EREG) expression through ERK inhibition, and suppressed the activation of their receptors, ErbBs, via a positive feedback loop. Moreover, mass spectrometry analysis combined with computer simulation revealed that Laxiflorin B binds covalently to Cys-183 in the ATP-binding pocket of ERK1 via the D-ring, and Cys-178 of ERK1 through non-inhibitory binding of the A-ring. In a NSCLC tumor xenograft model in nude mice, Laxiflorin B also exhibited strong tumor suppressive effects with low toxicity and AREG and EREG were identified as biomarkers of Laxiflorin B efficacy. Finally, Laxiflorin B-4, a C-6 analog of Laxiflorin B, exhibited higher binding affinity for ERK1/2 and stronger tumor suppression. These findings provide a new approach to tumor inhibition using natural anticancer compounds.

The oncogenic role of LGR6 overexpression induced by aberrant Wnt/β-catenin signaling in lung cancer

BACKGROUND

Molecular abnormalities in the Wnt/β-catenin pathway confer malignant phenotypes in lung cancer. Previously, we identified the association of leucine-rich repeat-containing G protein-coupled receptor 6 (LGR6) with oncogenic Wnt signaling, and its downregulation upon β-catenin knockdown in non-small cell lung cancer (NSCLC) cells carrying CTNNB1 mutations. The aim of this study was to explore the mechanisms underlying this association and the accompanying phenotypes.

METHODS

LGR6 expression in lung cancer cell lines and surgical specimens was analyzed using quantitative RT-PCR and immunohistochemistry. Cell growth was assessed using colony formation assay. Additionally, mRNA sequencing was performed to compare the expression profiles of cells subjected to different treatments.

RESULTS

LGR6 was overexpressed in small cell lung cancer (SCLC) and NSCLC cell lines, including the CTNNB1-mutated NSCLC cell lines HCC15 and A427. In both cell lines, LGR6 knockdown inhibited cell growth. LGR6 expression was upregulated in spheroids compared to adherent cultures of A427 cells, suggesting that LGR6 participates in the acquisition of cancer stem cell properties. Immunohistochemical analysis of lung cancer specimens revealed that the LGR6 protein was predominantly overexpressed in SCLCs, large cell neuroendocrine carcinomas, and lung adenocarcinomas, wherein LGR6 overexpression was associated with vascular invasion, the wild-type EGFR genotype, and an unfavorable prognosis. Integrated mRNA sequencing analysis of HCC15 and A427 cells with or without LGR6 knockdown revealed LGR6-related pathways and genes associated with cancer development and stemness properties.

CONCLUSIONS

Our findings highlight the oncogenic roles of LGR6 overexpression induced by aberrant Wnt/β-catenin signaling in lung cancer.

Construction and validation of a novel prognostic model of neutrophil‑related genes signature of lung adenocarcinoma

Lung adenocarcinoma (LUAD) remains an incurable disease with a poor prognosis. This study aimed to explore neutrophil‑related genes (NRGs) and develop a prognostic signature for predicting the prognosis of LUAD. NRGs were obtained by intersecting modular genes identified by weighted gene co-expression network analysis (WGCNA) using bulk RNA-seq data and the marker genes of neutrophils identified from single-cell RNA-sequencing(scRNA-seq) data. Univariate Cox regression, least absolute shrinkage and selection operator (LASSO), and multivariate Cox analyses were run to construct a prognostic signature, follow by delineation of risk groups, and external validation. Analyses of ESTIMAT, immune function, Tumor Immune Dysfunction and Exclusion (TIDE) scores, Immune cell Proportion Score (IPS), and immune checkpoint genes between high- and low-risk groups were performed, and then analyses of drug sensitivity to screen for sensitive anticancer drugs in high-risk groups. A total of 45 candidate NRGs were identified, of which PLTP, EREG, CD68, CD69, PLAUR, and CYP27A1 were considered to be significantly associated with prognosis in LUAD and were used to construct a prognostic signature. Correlation analysis showed significant differences in the immune landscape between high- and low-risk groups. In addition, our prognostic signature was important for predicting drug sensitivity in the high-risk group. Our study screened for NRGs in LUAD and constructed a novel and effective signature, revealing the immune landscape and providing more appropriate guidance protocols in LUAD treatment.

Mimicking Tumor Cell Heterogeneity of Colorectal Cancer in a Patient-derived Organoid-Fibroblast Model

BACKGROUND & AIMS

Patient-derived organoid cancer models are generated from epithelial tumor cells and reflect tumor characteristics. However, they lack the complexity of the tumor microenvironment, which is a key driver of tumorigenesis and therapy response. Here, we developed a colorectal cancer organoid model that incorporates matched epithelial cells and stromal fibroblasts.

METHODS

Primary fibroblasts and tumor cells were isolated from colorectal cancer specimens. Fibroblasts were characterized for their proteome, secretome, and gene expression signatures. Fibroblast/organoid co-cultures were analyzed by immunohistochemistry and compared with their tissue of origin, as well as on gene expression levels compared with standard organoid models. Bioinformatics deconvolution was used to calculate cellular proportions of cell subsets in organoids based on single-cell RNA sequencing data.

RESULTS

Normal primary fibroblasts, isolated from tumor adjacent tissue, and cancer associated fibroblasts retained their molecular characteristics in vitro, including higher motility of cancer associated compared with normal fibroblasts. Importantly, both cancer-associated fibroblasts and normal fibroblasts supported cancer cell proliferation in 3D co-cultures, without the addition of classical niche factors. Organoids grown together with fibroblasts displayed a larger cellular heterogeneity of tumor cells compared with mono-cultures and closely resembled the in vivo tumor morphology. Additionally, we observed a mutual crosstalk between tumor cells and fibroblasts in the co-cultures. This was manifested by considerably deregulated pathways such as cell-cell communication and extracellular matrix remodeling in the organoids. Thrombospondin-1 was identified as a critical factor for fibroblast invasiveness.

CONCLUSION

We developed a physiological tumor/stroma model, which will be vital as a personalized tumor model to study disease mechanisms and therapy response in colorectal cancer.

EREG is a risk factor for the prognosis of patients with cervical cancer

Background

Cervical cancer continues to threaten women's health worldwide. Identifying critical oncogenic molecules is important to drug development and prognosis prediction for patients with cervical cancer. Recent studies have demonstrated that epiregulin (EREG) is upregulated in various cancer types, which contributes to cancer progression by triggering the EGFR signaling pathway. However, the role of EREG is still unclear.

Methods

In this study, we first conducted a comprehensive biological analysis to investigate the expression of EREG in cervical cancer. Then, we investigated the correlations between EREG expression level and clinicopathological features. In addition, we validated the effects of EREG expression on the proliferation and apoptosis of cervical cancer cells.

Results

Based on the public database, we found that the expression of EREG was higher in advanced cervical cancer samples. Survival analysis showed that EREG was a risk factor for the prognosis of cervical cancer. In vitro experiments demonstrated that EREG knockdown undermined proliferation and promoted apoptosis in cancer cells.

Conclusion

EREG plays a vital role in the progression of cervical cancer, which contributes to hyperactive cell proliferation and decreased cell apoptosis. It might be a valuable target for prognosis prediction and drug development for cervical cancer in the future.

The Yin and Yang of ERBB4: Tumor Suppressor and Oncoprotein

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

Mmp12 Is Upregulated by in utero Second-Hand Smoke Exposures and Is a Key Factor Contributing to Aggravated Lung Responses in Adult Emphysema, Asthma, and Lung Cancer Mouse Models

Matrix metalloproteinase-12 (Mmp12) is upregulated by cigarette smoke (CS) and plays a critical role in extracellular matrix remodeling, a key mechanism involved in physiological repair processes, and in the pathogenesis of emphysema, asthma, and lung cancer. While cigarette smoking is associated with the development of chronic obstructive pulmonary diseases (COPD) and lung cancer, in utero exposures to CS and second-hand smoke (SHS) are associated with asthma development in the offspring. SHS is an indoor air pollutant that causes known adverse health effects; however, the mechanisms by which in utero SHS exposures predispose to adult lung diseases, including COPD, asthma, and lung cancer, are poorly understood. In this study, we tested the hypothesis that in utero SHS exposure aggravates adult-induced emphysema, asthma, and lung cancer.

Methods: Pregnant BALB/c mice were exposed from gestational days 6–19 to either 3 or 10mg/m³ of SHS or filtered air. At 10, 11, 16, or 17weeks of age, female offspring were treated with either saline for controls, elastase to induce emphysema, house-dust mite (HDM) to initiate asthma, or urethane to promote lung cancer. At sacrifice, specific disease-related lung responses including lung function, inflammation, gene, and protein expression were assessed.

Results: In the elastase-induced emphysema model, in utero SHS-exposed mice had significantly enlarged airspaces and up-regulated expression of Mmp12 (10.3-fold compared to air-elastase controls). In the HDM-induced asthma model, in utero exposures to SHS produced eosinophilic lung inflammation and potentiated Mmp12 gene expression (5.7-fold compared to air-HDM controls). In the lung cancer model, in utero exposures to SHS significantly increased the number of intrapulmonary metastases at 58weeks of age and up-regulated Mmp12 (9.3-fold compared to air-urethane controls). In all lung disease models, Mmp12 upregulation was supported at the protein level.

Conclusion: Our findings revealed that in utero SHS exposures exacerbate lung responses to adult-induced emphysema, asthma, and lung cancer. Our data show that MMP12 is up-regulated at the gene and protein levels in three distinct adult lung disease models following in utero SHS exposures, suggesting that MMP12 is central to in utero SHS-aggravated lung responses.

The Role of EREG/EGFR Pathway in Tumor Progression

Aberrant activation of the epidermal growth factor receptor (EGFR/ERBB1) by erythroblastic leukemia viral oncogene homolog (ERBB) ligands contributes to various tumor malignancies, including lung cancer and colorectal cancer (CRC). Epiregulin (EREG) is one of the EGFR ligands and is low expressed in most normal tissues. Elevated EREG in various cancers mainly activates EGFR signaling pathways and promotes cancer progression. Notably, a higher EREG expression level in CRC with wild-type Kirsten rat sarcoma viral oncogene homolog (KRAS) is related to better efficacy of therapeutic treatment. By contrast, the resistance of anti-EGFR therapy in CRC was driven by low EREG expression, aberrant genetic mutation and signal pathway alterations. Additionally, EREG overexpression in non-small cell lung cancer (NSCLC) is anticipated to be a therapeutic target for EGFR-tyrosine kinase inhibitor (EGFR-TKI). However, recent findings indicate that EREG derived from macrophages promotes NSCLC cell resistance to EGFR-TKI treatment. The emerging events of EREG-mediated tumor promotion signals are generated by autocrine and paracrine loops that arise from tumor epithelial cells, fibroblasts, and macrophages in the tumor microenvironment (TME). The TME is a crucial element for the development of various cancer types and drug resistance. The regulation of EREG/EGFR pathways depends on distinct oncogenic driver mutations and cell contexts that allows specific pharmacological targeting alone or combinational treatment for tailored therapy. Novel strategies targeting EREG/EGFR, tumor-associated macrophages, and alternative activation oncoproteins are under development or undergoing clinical trials. In this review, we summarize the clinical outcomes of EREG expression and the interaction of this ligand in the TME. The EREG/EGFR pathway may be a potential target and may be combined with other driver mutation targets to combat specific cancers.

Hookah Smoke Mediates Cancer-Associated Epigenomic and Transcriptomic Signatures in Human Respiratory Epithelial Cells

Introduction

Although communal smoking of hookah by means of water pipes is perceived to be a safe alternative to cigarette smoking, the effects of hookah smoke in respiratory epithelia have not been well characterized. This study evaluated epigenomic and transcriptomic effects of hookah smoke relative to cigarette smoke in human respiratory epithelial cells.

Methods

Primary normal human small airway epithelial cells from three donors and cdk4 and hTERT-immortalized small airway epithelial cells and human bronchial epithelial cells were cultured for 5 days in normal media with or without cigarette smoke condensates (CSCs) or water pipe condensates (WPCs). Cell count, immunoblot, RNA sequencing, quantitative real-time reverse-transcriptase polymerase chain reaction, methylation-specific polymerase chain reaction, and quantitative chromatin immunoprecipitation techniques were used to compare effects of hookah and cigarette smoke on cell proliferation, global histone marks, gene expression, and promoter-related chromatin structure.

Results

CSC and WPC decreased global H4K16ac and H4K20me3 histone marks and mediated distinct and overlapping cancer-associated transcriptome signatures and pathway modulations that were cell line dependent and stratified across lung cancer cells in a histology-specific manner. Epiregulin encoding a master regulator of EGFR signaling that is overexpressed in lung cancers was up-regulated, whereas FILIP1L and ABI3BP encoding mediators of senescence that are repressed in lung cancers were down-regulated by CSC and WPC. Induction of epiregulin and repression of FILIP1L and ABI3BP by these condensates coincided with unique epigenetic alterations within the respective promoters.

Conclusions

These findings support translational studies to ascertain if hookah-mediated epigenomic and transcriptomic alterations in cultured respiratory epithelia are detectable and clinically relevant in hookah smokers.

Depletion of EREG enhances the osteo/dentinogenic differentiation ability of dental pulp stem cells via the p38 MAPK and Erk pathways in an inflammatory microenvironment

BACKGROUND

Epiregulin (EREG) is an important component of EGF and was demonstrated to promote the osteo/dentinogenic differentiation of stem cells from dental apical papilla (SCAPs). Whether EREG can stimulate the osteo/dentinogenic differentiation of dental pulp stem cells (DPSCs) in inflammatory environment is not clear. The purpose of the present study is to investigate the role of EREG on the osteo/dentinogenic differentiation ability of DPSCs in inflammatory environment.

METHODS

DPSCs were isolated from human third molars. Short hairpin RNAs (shRNAs) were used to knock down EREG expression in DPSCs. Recombinant human EREG (rhEREG) protein was used in the rescue experiment. TNF-α was employed to mimic the inflammatory environment in vitro. Alkaline phosphatase (ALP) staining, Alizarin red staining, quantitative calcium analysis, and real-time RT-PCR were performed to detect osteo/dentinogenic differentiation markers and related signalling pathways under normal and inflammatory conditions.

RESULTS

EREG depletion promoted the ALP activity and mineralization ability of DPSCs. The expression of BSP, DMP-1, and DSPP was also enhanced. Moreover, 50 ng/mL rhEREG treatment decreased the osteo/dentinogenic differentiation potential of DPSCs, while treatment with 10 ng/mL TNF-α for 4 h increased the expression of EREG in DPSCs. Conversely, EREG knockdown rescued the impaired osteo/dentinogenic differentiation ability caused by TNF-α treatment. Further mechanistic studies showed that EREG depletion activated the p38 MAPK and Erk signalling pathways in DPSCs under normal and inflammatory conditions.

CONCLUSIONS

Our results demonstrated that EREG could inhibit the osteo/dentinogenic differentiation potential of DPSCs via the p38 MAPK and Erk signalling pathways. Under inflammatory environment, EREG depletion enhanced osteo/dentinogenic differentiation potential of DPSCs by improving the expression of p-p38 MAPK and p-Erk.

3-Nitrobenzanthrone promotes malignant transformation in human lung epithelial cells through the epiregulin-signaling pathway

Exposure to environmental and occupational contaminants leads to lung cancer. 3-Nitrobenzanthrone (3-nitro-7H-benz[de]anthracen-7-one, 3-NBA) is a potential carcinogen in ambient air or diesel particulate matter. Studies have revealed that short-term exposure to 3-NBA induces cell death, reactive oxygen species activation, and DNA adduct formation and damage. However, details of the mechanism by which chronic exposure to 3-NBA influences lung carcinogenesis remain largely unknown. In this study, human lung epithelial BEAS-2B cells were continuously exposed to 0-10-μM 3-NBA for 6 months. NanoString analysis was conducted to evaluate gene expression in the cells, revealing that 3-NBA-mediated transformation results in a distinct gene expression signature including carbon cancer metabolism, metastasis, and angiogenesis. Alterations in tumor-promoting genes such as EREG (epiregulin), SOX9, E-cadherin, TWIST, and IL-6 were involved in epithelial cell aggressiveness. Kaplan-Meier plotter analyses indicated that increased EREG and IL-6 expressions in early-stage lung cancer cells are correlated with poor survival. In vivo xenografts on 3-NBA-transformed cells exhibited prominent tumor formation and metastasis. EREG knockout cells exposed to 3-NBA for a short period exhibited high apoptosis and low colony formation. By contrast, overexpression of EREG in 3-NBA-transformed cells markedly activated the PI3K/AKT and MEK/ERK signaling pathways, resulting in tumorigenicity. Furthermore, elevated IL-6 and EREG expressions synergistically led to STAT3 signaling activation, resulting in clonogenic cell survival and migration. Taken together, chronic exposure of human lung epithelial cells to 3-NBA leads to malignant transformation, in which the EREG signaling pathway plays a pivotal mediating role. • Short-term exposure of lung epithelial cells to 3-NBA can lead to ROS production and cell apoptosis. • Long-term chronic exposure to 3-NBA upregulates the levels of tumor-promoting genes such as EREG and IL-6. • Increased EREG expression in 3-NBA-transformed cells markedly contributes to tumorigenesis through PI3K/AKT and MEK/ERK activation and synergistically enhances the IL-6/STAT3 signaling pathway, which promotes tumorigenicity.

The Unsupervised Feature Selection Algorithms Based on Standard Deviation and Cosine Similarity for Genomic Data Analysis

To tackle the challenges in genomic data analysis caused by their tens of thousands of dimensions while having a small number of examples and unbalanced examples between classes, the technique of unsupervised feature selection based on standard deviation and cosine similarity is proposed in this paper. We refer to this idea as SCFS (Standard deviation and Cosine similarity based Feature Selection). It defines the discernibility and independence of a feature to value its distinguishable capability between classes and its redundancy to other features, respectively. A 2-dimensional space is constructed using discernibility as x-axis and independence as y-axis to represent all features where the upper right corner features have both comparatively high discernibility and independence. The importance of a feature is defined as the product of its discernibility and its independence (i.e., the area of the rectangular enclosed by the feature’s coordinate lines and axes). The upper right corner features are by far the most important, comprising the optimal feature subset. Based on different definitions of independence using cosine similarity, there are three feature selection algorithms derived from SCFS. These are SCEFS (Standard deviation and Exponent Cosine similarity based Feature Selection), SCRFS (Standard deviation and Reciprocal Cosine similarity based Feature Selection) and SCAFS (Standard deviation and Anti-Cosine similarity based Feature Selection), respectively. The KNN and SVM classifiers are built based on the optimal feature subsets detected by these feature selection algorithms, respectively. The experimental results on 18 genomic datasets of cancers demonstrate that the proposed unsupervised feature selection algorithms SCEFS, SCRFS and SCAFS can detect the stable biomarkers with strong classification capability. This shows that the idea proposed in this paper is powerful. The functional analysis of these biomarkers show that the occurrence of the cancer is closely related to the biomarker gene regulation level. This fact will benefit cancer pathology research, drug development, early diagnosis, treatment and prevention.

Identification of PDL1-Related Biomarkers to Select Lung Adenocarcinoma Patients for PD1/PDL1 Inhibitors

PD1/PDL1 inhibitors have been adopted for the treatment of advanced non-small-cell lung cancer, and PDL1 expression has been investigated as a predictive biomarker for PD1/PDL1 inhibitor therapy. However, PDL1 lacks diagnostic accuracy in differentiating patients who are likely or unlikely to benefit. So, it is urgent and clinically significant to identify other associated predictive biomarkers for PD1/PDL1 inhibitor therapy. Our work was to identify PDL1-related biomarkers that could improve the patient selection for PD1/PDL1 inhibitor treatment. We obtained 500 genes coexpressed with PDL1 in lung adenocarcinoma from the TCGA database. Then, we identified 125 out of 500 genes differentially expressed in lung adenocarcinoma. A total of 39 genes were distinguished with prognostic value and associated with overall survival. Median survival time analysis based on gene expression level, protein-protein interaction analysis, GO and KEGG enrichment analyses, and significant GO and KEGG function consistency analyses were conducted to screen candidate biomarkers. Three candidate genes, BRCA1, BRIP1, and EREG, were identified to be functionally significantly coexpressed with PDL1. Functional enrichment analysis and protein-protein interaction networks further showed that these genes mainly participated in immune response and cell activation. Additionally, to find potential adjuvant therapeutic targets in PD1/PDL1 inhibitor treatment, we performed transcription factor prediction analysis. A group of negative differential expression but PDL1-related biomarkers has been identified, which might help to assess the clinical management of lung cancer patients. A combination of potential biomarkers and adjuvant therapeutic targets with PDL1 will predict the response to PD1/PDL1 inhibitors more accurately and help with the patient selection for more personalized immune checkpoint inhibitor treatment.

Targeting the Tumor Microenvironment: An Unexplored Strategy for Mutant KRAS Tumors

Current evidence strongly suggests that cancer cells depend on the microenvironment in order to thrive. In fact, signals from the surrounding tumor microenvironment are crucial for cancer cells´ aggressiveness, altering their expression profile and favoring their metastatic potential. As such, targeting the tumor microenvironment to impair cancer progression became an attractive therapeutic option. Interestingly, it has been shown that oncogenic KRAS signaling promotes a pro-tumorigenic microenvironment, and the associated crosstalk alters the expression profile of cancer cells. These findings award KRAS a key role in controlling the interactions between cancer cells and the microenvironment, granting cancer a poor prognosis. Given the lack of effective approaches to target KRAS itself or its downstream effectors in the clinic, exploring such interactions may open new perspectives on possible therapeutic strategies to hinder mutant KRAS tumors. This review highlights those communications and their implications for the development of effective therapies or to provide insights regarding response to existing regimens.

Functional suppression of Epiregulin impairs angiogenesis and aggravates left ventricular remodeling by disrupting the extracellular-signal-regulated kinase1/2 signaling pathway in rats after acute myocardial infarction

Acute myocardial infarction (AMI), a severe consequence of coronary atherosclerotic heart disease, is often associated with high mortality and morbidity. Emerging evidence have shown that the inhibition of the extracellular-signal-regulated kinase (ERK) signaling pathway appears to protect against AMI. Epiregulin (EREG) is an autocrine growth factor that is believed to activate the MEK/ERK signaling pathway. Therefore, the aim of the present study was to determine the expression patterns of EREG in AMI and to further study its effects on AMI induced experimentally in rats focusing on angiogenesis and left ventricular remodeling. Microarray-based gene expression profiling of AMI was used to identify differentially expressed genes. To understand the biological significance of EREG and whether it is involved in AMI disease through the ERK1/2 signaling pathway, rats after AMI were treated with small interfering RNA (siRNA) against EREG, an ERK1/2 pathway inhibitor, PD98059, or both of them. The microarray data sets GSE66360 and GSE46395 showed that EREG was robustly induced in AMI. Both siRNA-mediated depletion of EREG and PD98059 treatment were shown to significantly increase infarct size and left ventricular cardiomyocyte loss and enhance left ventricular remodeling. In addition, we also found that the ERK1/2 signaling pathway was inhibited following siRNA-mediated EREG inhibition and PD98059 could enhance the effects of EREG inhibition on AMI. In conclusion, these findings highlight that the silencing of EREG inhibits angiogenesis and promotes left ventricular remodeling by disrupting the ERK1/2 signaling pathway, providing a novel therapeutic target for limiting AMI.

The miR-186-3p/EREG axis orchestrates tamoxifen resistance and aerobic glycolysis in breast cancer cells

Tamoxifen resistance is one of the major challenges for its medical uses in estrogen receptor (ER)-positive breast cancer. Aerobic glycolysis, an anomalous characteristic of glucose metabolism in cancer cells, has been shown to associate with the resistance to chemotherapeutic agents. It remains, however, largely unclear whether and how tamoxifen resistance contributes to aerobic glycolysis in breast cancer. Here, we report that tamoxifen resistance is associated with enhanced glycolysis in ER-positive breast cancer cells. We demonstrate that EREG, an agonist of EGFR, has an important role in enhancing glycolysis via activating EGFR signaling and its downstream glycolytic genes in tamoxifen-resistant breast cancer cells. We further show that EREG is a direct target of miR-186-3p and that downregulation of miR-186-3p by tamoxifen results in EREG upregulation in tamoxifen-resistant breast cancer cells. Importantly, systemic delivery of cholesterol-modified agomiR-186-3p to mice bearing tamoxifen-resistant breast tumors effectively attenuates both tumor growth and [¹⁸F]-fluoro-deoxyglucose ([¹⁸F]-FDG) uptake. Together, our results reveal a novel molecular mechanism of resistance to hormone therapies in which the miR-186-3p/EREG axis orchestrates tamoxifen resistance and aerobic glycolysis in ER-positive breast cancer, suggesting targeting miR-186-3p as a promising strategy for therapeutic intervention in endocrine-resistant breast tumors.

Dual inhibition of MEK and p38 impairs tumor growth in KRAS-mutated non-small cell lung cancer

Despite the high frequency of KRAS mutations in non-small cell lung cancer (NSCLC), therapeutic modalities targeting KRAS-mutated NSCLC have not been established. Based on our previous findings that mutant KRAS knockdown sensitized NSCLC cells to a p38 inhibitor, the growth-inhibitory effect of dual MEK and p38 inhibition on tumor growth in NSCLC cells harboring KRAS mutations was investigated. In KRAS-mutated NSCLC cells, the MEK inhibitor, selumetinib, inhibited cell growth in a dose-dependent manner, and its growth-inhibitory effect was enhanced by combined treatment with the p38 inhibitor LY2228820. Similarly, another pair of MEK and p38 inhibitors also exhibited antitumor activity. Small interfering RNAs (siRNAs) against MAPK14, which encodes p38α MAPK, enhanced the growth-inhibitory effect of the MEK inhibitors in NSCLC cells with KRAS mutations. Notably, MEK inhibitors reduced p38 expression levels but increased p38 phosphorylation levels, resulting in sensitization to p38 inhibitors in KRAS-mutated NSCLC cells. These results provide evidence that dual MEK and p38 inhibition could be a potent therapeutic strategy against oncogenic KRAS-driven NSCLC.

Elevated epiregulin expression predicts poor prognosis in gastric cancer

Epiregulin (EREG) is a novel family member of EGF-like ligands and have elevated expression in a variety of human cancers. EREG expression promotes tumor progression and metastasis and reduces patient survival. However, the expression of EREG and its prognostic value are not clear in gastric cancer (GC). We assessed EREG mRNA and protein expression in GC tissues from Chinese patients using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical staining of tissue microarray, and analyzed the correlation between the level of EREG expression and patient clinical characteristics and prognosis. We found that EREG expression was significantly higher in GC tissues than in matched adjacent noncancerous tissues. High EREG protein expression in GC was significantly associated with TNM stage including tumor size, lymph node metastases and distant metastases as well as poor overall survival. These finding demonstrate that EREG is an independent prognostic biomarker for GC.

Comparative mRNA and miRNA transcriptome analysis of a mouse model of IGFIR-driven lung cancer

Mouse models of cancer play an important role in elucidating the molecular mechanisms that contribute to tumorigenesis. The extent to which these models resemble one another and their human counterparts at the molecular level is critical in understanding tumorigenesis. In this study, we carried out a comparative gene expression analysis to generate a detailed molecular portrait of a transgenic mouse model of IGFIR-driven lung cancer. IGFIR-driven tumors displayed a strong resemblance with established mouse models of lung adenocarcinoma, particularly EGFR-driven models highlighted by elevated levels of the EGFR ligands Ereg and Areg. Cross-species analysis revealed a shared increase in human lung adenocarcinoma markers including Nkx2.1 and Napsa as well as alterations in a subset of genes with oncogenic and tumor suppressive properties such as Aurka, Ret, Klf4 and Lats2. Integrated miRNA and mRNA analysis in IGFIR-driven tumors identified interaction pairs with roles in ErbB signaling while cross-species analysis revealed coordinated expression of a subset of conserved miRNAs and their targets including miR-21-5p (Reck, Timp3 and Tgfbr3). Overall, these findings support the use of SPC-IGFIR mice as a model of human lung adenocarcinoma and provide a comprehensive knowledge base to dissect the molecular pathogenesis of tumor initiation and progression.

Current Challenges and Opportunities in Treating Glioblastoma

Glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor, has a high mortality rate despite extensive efforts to develop new treatments. GBM exhibits both intra- and intertumor heterogeneity, lending to resistance and eventual tumor recurrence. Large-scale genomic and proteomic analysis of GBM tumors has uncovered potential drug targets. Effective and "druggable" targets must be validated to embark on a robust medicinal chemistry campaign culminating in the discovery of clinical candidates. Here, we review recent developments in GBM drug discovery and delivery. To identify GBM drug targets, we performed extensive bioinformatics analysis using data from The Cancer Genome Atlas project. We discovered 20 genes, BOC, CLEC4GP1, ELOVL6, EREG, ESR2, FDCSP, FURIN, FUT8-AS1, GZMB, IRX3, LITAF, NDEL1, NKX3-1, PODNL1, PTPRN, QSOX1, SEMA4F, TH, VEGFC, and C20orf166AS1 that are overexpressed in a subpopulation of GBM patients and correlate with poor survival outcomes. Importantly, nine of these genes exhibit higher expression in GBM versus low-grade glioma and may be involved in disease progression. In this review, we discuss these proteins in the context of GBM disease progression. We also conducted computational multi-parameter optimization to assess the blood-brain barrier (BBB) permeability of small molecules in clinical trials for GBM treatment. Drug delivery in the context of GBM is particularly challenging because the BBB hinders small molecule transport. Therefore, we discuss novel drug delivery methods, including nanoparticles and prodrugs. Given the aggressive nature of GBM and the complexity of targeting the central nervous system, effective treatment options are a major unmet medical need. Identification and validation of biomarkers and drug targets associated with GBM disease progression present an exciting opportunity to improve treatment of this devastating disease.

The ERBB network facilitates KRAS-driven lung tumorigenesis

KRAS is the most frequently mutated driver oncogene in human adenocarcinoma of the lung. There are presently no clinically proven strategies for treatment of KRAS-driven lung cancer. Activating mutations in KRAS are thought to confer independence from upstream signaling; however, recent data suggest that this independence may not be absolute. We show that initiation and progression of KRAS-driven lung tumors require input from ERBB family receptor tyrosine kinases (RTKs): Multiple ERBB RTKs are expressed and active from the earliest stages of KRAS-driven lung tumor development, and treatment with a multi-ERBB inhibitor suppresses formation of KRASG12D-driven lung tumors. We present evidence that ERBB activity amplifies signaling through the core RAS pathway, supporting proliferation of KRAS-mutant tumor cells in culture and progression to invasive disease in vivo. Brief pharmacological inhibition of the ERBB network enhances the therapeutic benefit of MEK (mitogen-activated protein kinase kinase) inhibition in an autochthonous tumor setting. Our data suggest that lung cancer patients with KRAS-driven disease may benefit from inclusion of multi-ERBB inhibitors in rationally designed treatment strategies.

Transcriptional profiling of human bronchial epithelial cell BEAS-2B exposed to diesel and biomass ultrafine particles

BACKGROUND

Emissions from diesel vehicles and biomass burning are the principal sources of primary ultrafine particles (UFP). The exposure to UFP has been associated to cardiovascular and pulmonary diseases, including lung cancer. Although many aspects of the toxicology of ambient particulate matter (PM) have been unraveled, the molecular mechanisms activated in human cells by the exposure to UFP are still poorly understood. Here, we present an RNA-seq time-course experiment (five time point after single dose exposure) used to investigate the differential and temporal changes induced in the gene expression of human bronchial epithelial cells (BEAS-2B) by the exposure to UFP generated from diesel and biomass combustion. A combination of different bioinformatics tools (EdgeR, next-maSigPro and reactome FI app-Cytoscape and prioritization strategies) facilitated the analyses the temporal transcriptional pattern, functional gene set enrichment and gene networks related to cellular response to UFP particles.

RESULTS

The bioinformatics analysis of transcriptional data reveals that the two different UFP induce, since the earliest time points, different transcriptional dynamics resulting in the activation of specific genes. The functional enrichment of differentially expressed genes indicates that the exposure to diesel UFP induces the activation of genes involved in TNFα signaling via NF-kB and inflammatory response, and hypoxia. Conversely, the exposure to ultrafine particles from biomass determines less distinct modifications of the gene expression profiles. Diesel UFP exposure induces the secretion of biomarkers associated to inflammation (CCXL2, EPGN, GREM1, IL1A, IL1B, IL6, IL24, EREG, VEGF) and transcription factors (as NFE2L2, MAFF, HES1, FOSL1, TGIF1) relevant for cardiovascular and lung disease. By means of network reconstruction, four genes (STAT3, HIF1a, NFKB1, KRAS) have emerged as major regulators of transcriptional response of bronchial epithelial cells exposed to diesel exhaust.

CONCLUSIONS

Overall, this work highlights modifications of the transcriptional landscape in human bronchial cells exposed to UFP and sheds new lights on possible mechanisms by means of which UFP acts as a carcinogen and harmful factor for human health.

PGE2/EP3/SRC signaling induces EGFR nuclear translocation and growth through EGFR ligands release in lung adenocarcinoma cells

Prostaglandin E₂ (PGE₂) interacts with tyrosine kinases receptor signaling in both tumor and stromal cells supporting tumor progression. Here we demonstrate that in non-small cell lung carcinoma (NSCLC) cells, A549 and GLC82, PGE₂ promotes nuclear translocation of epidermal growth factor receptor (nEGFR), affects gene expression and induces cell growth. Indeed, cyclin D1, COX-2, iNOS and c-Myc mRNA levels are upregulated following PGE₂ treatment. The nuclear localization sequence (NLS) of EGFR as well as its tyrosine kinase activity are required for the effect of PGE₂ on nEGFR and downstream signaling activities. PGE₂ binds its bona fide receptor EP3 which by activating SRC family kinases, induces ADAMs activation which, in turn, releases EGFR-ligands from the cell membrane and promotes nEGFR. Amphiregulin (AREG) and Epiregulin (EREG) appear to be involved in nEGFR promoted by the PGE₂/EP3-SRC axis. Pharmacological inhibition or silencing of the PGE₂/EP3/SRC-ADAMs signaling axis or EGFR ligands i.e. AREG and EREG expression abolishes nEGFR induced by PGE₂. In conclusion, PGE₂ induces NSCLC cell proliferation by EP3 receptor, SRC-ADAMs activation, EGFR ligands shedding and finally, phosphorylation and nEGFR. Since nuclear EGFR is a hallmark of cancer aggressiveness, our findings reveal a novel mechanism for the contribution of PGE₂ to tumor progression.

Muc1 knockout potentiates murine lung carcinogenesis involving an epiregulin-mediated EGFR activation feedback loop

Mucin 1 (MUC1) is a tumor antigen that is aberrantly overexpressed in various cancers, including lung cancer. Our previous in vitro studies showed that MUC1 facilitates carcinogen-induced EGFR activation and transformation in human lung bronchial epithelial cells (HBECs), which along with other reports suggests an oncogenic property for MUC1 in lung cancer. However, direct evidence for the role of MUC1 in lung carcinogenesis is lacking. In this study, we used the 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced A/J mouse lung tumor model to investigate the effect of whole-body Muc1 knockout (KO) on carcinogen-induced lung carcinogenesis. Surprisingly, lung tumor multiplicity was significantly increased in Muc1 KO compared to wild-type (WT) mice. The EGFR/AKT pathway was unexpectedly activated, and expression of the EGFR ligand epiregulin (EREG) was increased in the lung tissues of the Muc1 KO compared to the WT mice. EREG stimulated proliferation and protected against cigarette smoke extract (CSE)-induced cytotoxicity in in vitro cultured human bronchial epithelial cells. Additionally, we determined that MUC1 was expressed in human fibroblast cell lines where it suppressed CSE-induced EREG production. Further, suppression of MUC1 cellular activity with GO-201 enhanced EREG production in lung cancer cells, which in turn protected cancer cells from GO-201-induced cell death. Moreover, an inverse association between MUC1 and EREG was detected in human lung cancer, and EREG expression was inversely associated with patient survival. Together, these results support a promiscuous role of MUC1 in lung cancer development that may be related to cell-type specific functions of MUC1 in the tumor microenvironment, and MUC1 deficiency in fibroblasts and malignant cells results in increased EREG production that activates the EGFR pathway for lung carcinogenesis.

Potential lung carcinogenicity induced by chronic exposure to PM2.5 in the rat

Exposure to fine particulate matter (PM_2.5) may increase lung cancer risk, but the underlying mechanisms are poorly understood. This study explored the potential carcinogenicity in rat lung induced by chronic exposure to PM_2.5. Adult male rats (200-220 g) were treated with PM_2.5 (10 mg/kg body weight) by tracheal perfusion once per week for 1 year; the rats were killed, and expression of tumor markers (carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), squamous cell carcinoma antigen (SCCA)), cancer-related genes, and pathological changes were detected. Chronic treatment with PM_2.5 significantly increased SCCA and NSE expression in rat lung tissue and serum. Damaged lung tissue structure was observed by hematoxylin and eosin staining. Although no evidence of tumors was detected, the Wnt/β-catenin signaling, epithelial-mesenchymal transition, vascular endothelial growth factor, and epidermal growth factor receptor pathways were all activated or overexpressed and likely involved in the potential carcinogenicity in the rat model. Additionally, abnormal expression of the proto-oncogenes c-Myc and K-Ras and tumor suppressor p53 can be seen in lung tissue induced by PM_2.5 exposure. Chronic exposure to PM_2.5 has the potential to be carcinogenic in rat lung.

A Phase Ib Dose-Escalation Study of the Safety, Tolerability, and Pharmacokinetics of Cobimetinib and Duligotuzumab in Patients with Previously Treated Locally Advanced or Metastatic Cancers with Mutant KRAS

Lessons Learned.

Cobimetinib and duligotuzumab were well tolerated as single agents and in combination with other agents.

The cobimetinib and duligotuzumab combination was associated with increased toxicity, most notably gastrointestinal, and limited efficacy in the patient population tested.

Background.

KRAS‐mutant tumors possess abnormal mitogen‐activated protein kinases (MAPK) pathway signaling, leading to dysregulated cell proliferation. Cobimetinib blocks MAPK signaling. The dual‐action antibody duligotuzumab (MEHD7945A) inhibits ligand binding to both epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 3 (HER3). Blockade of EGFR/HER3 and inhibition of mitogen‐activated protein kinase (MEK) in KRAS‐mutant tumors may provide additive benefit.

Methods.

Patients with KRAS‐mutant solid tumors were eligible for this phase Ib dose‐escalation study with a planned expansion phase. Duligotuzumab was given intravenously (IV) at 1,100 mg every 2 weeks (q2w), while cobimetinib was given orally in a standard 3 + 3 design to identify the recommended phase II dose (RP2D). The primary objective was to evaluate the safety and tolerability of this combination.

Results.

Twenty‐three patients were enrolled. Dose‐limiting toxicities (DLTs) included grade 4 hypokalemia and grade 3 mucosal inflammation, asthenia, and dermatitis acneiform. Seventy percent of patients experienced grade 3 or worse adverse events (AEs). Five (22%) and 12 (52%) patients missed at least 1 dose of duligotuzumab and cobimetinib, respectively, and 9 (39%) patients required a cobimetinib dose reduction. Three (13%) patients discontinued due to an AE. Best response was limited to 9 patients with stable disease and 13 patients with progressive disease.

Conclusion.

Given the limited tolerability and efficacy of this combination, the study did not proceed to expansion stage and closed for enrollment.

Inactivation of ABL kinases suppresses non-small cell lung cancer metastasis

Current therapies to treat non-small cell lung carcinoma (NSCLC) have proven ineffective owing to transient, variable, and incomplete responses. Here we show that ABL kinases, ABL1 and ABL2, promote metastasis of lung cancer cells harboring EGFR or KRAS mutations. Inactivation of ABL kinases suppresses NSCLC metastasis to brain and bone, and other organs. ABL kinases are required for expression of prometastasis genes. Notably, ABL1 and ABL2 depletion impairs extravasation of lung adenocarcinoma cells into the lung parenchyma. We found that ABL-mediated activation of the TAZ and β-catenin transcriptional coactivators is required for NSCLC metastasis. ABL kinases activate TAZ and β-catenin by decreasing their interaction with the β-TrCP ubiquitin ligase, leading to increased protein stability. High-level expression of ABL1, ABL2, and a subset of ABL-dependent TAZ- and β-catenin-target genes correlates with shortened survival of lung adenocarcinoma patients. Thus, ABL-specific allosteric inhibitors might be effective to treat metastatic lung cancer with an activated ABL pathway signature.

Targeting the KRAS Pathway in Non-Small Cell Lung Cancer

: Lung cancer remains the leading cause of cancer-related deaths worldwide. However, significant progress has been made individualizing therapy based on molecular aberrations (e.g., EGFR, ALK) and pathologic subtype. KRAS is one of the most frequently mutated genes in non-small cell lung cancer (NSCLC), found in approximately 30% of lung adenocarcinomas, and is thus an appealing target for new therapies. Although no targeted therapy has yet been approved for the treatment of KRAS-mutant NSCLC, there are multiple potential therapeutic approaches. These may include direct inhibition of KRAS protein, inhibition of KRAS regulators, alteration of KRAS membrane localization, and inhibition of effector molecules downstream of mutant KRAS. This article provides an overview of the KRAS pathway in lung cancer and related therapeutic strategies under investigation.

IMPLICATIONS FOR PRACTICE

The identification of oncogene-addicted cancers and specific inhibitors has revolutionized non-small cell lung cancer (NSCLC) treatment and outcomes. One of the most commonly mutated genes in adenocarcinoma is KRAS, found in approximately 30% of lung adenocarcinomas, and thus it is an appealing target for new therapies. This review provides an overview of the KRAS pathway and related targeted therapies under investigation in NSCLC. Some of these agents may play a key role in KRAS-mutant NSCLC treatment in the future.

Gene Expression of the EGF System-a Prognostic Model in Non-Small Cell Lung Cancer Patients Without Activating EGFR Mutations

OBJECTIVES: Contradicting results have been demonstrated for the expression of the epidermal growth factor receptor (EGFR) as a prognostic marker in non–small cell lung cancer (NSCLC). The complexity of the EGF system with four interacting receptors and more than a dozen activating ligands is a likely explanation. The aim of this study is to demonstrate that the combined network of receptors and ligands from the EGF system is a prognostic marker. MATERIAL AND METHODS: Gene expression of the receptors EGFR, HER2, HER3, HER4, and the ligands AREG, HB-EGF, EPI, TGF-α, and EGF was measured by quantitative polymerase chain reaction in tumor samples from 100 NSCLC patients without EGFR activating mutations. Results were dichotomized into high or low levels of target expression. Coexpression of the ligands and receptors was observed, and a score was developed based on the summed effect of receptors and ligands. Akaike’s information criteria selected the optimal score. Results were correlated with age, sex, stage, histology, performance status, and overall survival. RESULTS: Patients were randomly split 1:1 to create test and validation cohorts. In multivariate analyses, the only individual prognostic marker was EPI (hazard ratio [HR] 0.38 [0.20-0.72], P = .003). The optimal score in the test cohort was validated as a marker of inferior survival in the validation cohort and by bootstrapping. Multivariate analysis confirmed the combined score as a prognostic marker of inferior survival (HR 3.75 [2.17-6.47], P < .00001). CONCLUSION: Our study has developed a model that takes the complexity of the EGF system into account and shows that this model is a strong prognostic marker in NSCLC patients.

Chronic Obstructive Pulmonary Disease Is Not Associated with KRAS Mutations in Non-Small Cell Lung Cancer

Mutations in epithelial growth factor receptor (EGFR), as well as in the EGFR downstream target KRAS are frequently observed in non-small cell lung cancer (NSCLC). Chronic obstructive pulmonary disease (COPD), an independent risk factor for developing NSCLC, is associated with an increased activation of EGFR. In this study we determined presence of EGFR and KRAS hotspot mutations in 325 consecutive NSCLC patients subjected to EGFR and KRAS mutation analysis in the diagnostic setting and for whom the pulmonary function has been determined at time of NSCLC diagnosis. Information about age at diagnosis, sex, smoking status, forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV₁) was collected. Chronic obstructive pulmonary disease(COPD) was defined according to 2013 GOLD criteria. Chi-Square, student t-test and multivariate logistic regression were used to analyze the data. A total of 325 NSCLC patients were included, 193 with COPD and 132 without COPD. COPD was not associated with presence of KRAS hotspot mutations, while EGFR mutations were significantly higher in non-COPD NSCLC patients. Both female gender (HR 2.61; 95% CI: 1.56–4.39; p<0.001) and smoking (HR 4.10; 95% CI: 1.14–14.79; p = 0.03) were associated with KRAS mutational status. In contrast, only smoking (HR 0.11; 95% CI: 0.04–0.32; p<0.001) was inversely associated with EGFR mutational status. Smoking related G>T and G>C transversions were significantly more frequent in females (86.2%) than in males (61.5%) (p = 0.008). The exon 19del mutation was more frequent in non-smokers (90%) compared to current or past smokers (36.8%). In conclusion, KRAS mutations are more common in females and smokers, but are not associated with COPD-status in NSCLC patients. EGFR mutations are more common in non-smoking NSCLC patients.

Epiregulin is required for lung tumor promotion in a murine two-stage carcinogenesis model

Adenocarcinoma accounts for ∼40% of lung cancer, equating to ∼88 500 new patients in 2015, most of who will succumb to this disease, thus, the public health burden is evident. Unfortunately, few early biomarkers as well as effective therapies exist, hence the need for novel targets in lung cancer treatment. We previously identified epiregulin (Ereg), an EGF-like ligand, as a biomarker in several mouse lung cancer models. In the present investigation we used a primary two-stage initiation/promotion model to test our hypothesis that Ereg deficiency would reduce lung tumor promotion in mice. We used 3-methylcholanthrene (initiator) or oil vehicle followed by multiple weekly exposures to butylated hydroxytoluene (BHT; promoter) in mice lacking Ereg (Ereg^-/- ) and wildtype controls (BALB/ByJ; Ereg^+/+ ) and examined multiple time points and endpoints (bronchoalveolar lavage analysis, tumor analysis, mRNA expression, ELISA, wound assay) during tumor promotion. At the early time points (4 and 12 wk), we observed significantly reduced amounts of inflammation (macrophages, PMNs) in the Ereg^-/- mice compared to controls (Ereg^+/+ ). At 20 wk, tumor multiplicity was also significantly decreased in the Ereg^-/- mice versus controls (Ereg^+/+ ). IL10 expression, an anti-inflammatory mediator, and downstream signaling events (Stat3) were significantly increased in the Ereg^-/- mice in response to BHT, supporting both reduced inflammation and tumorigenesis. Lastly, wound healing was significantly increased with recombinant Ereg in both human and mouse lung epithelial cell lines. These results indicate that Ereg has proliferative potential and may be utilized as an early cancer biomarker as well as a novel potential therapeutic target. © 2016 Wiley Periodicals, Inc.

HGF/Met and FOXM1 form a positive feedback loop and render pancreatic cancer cells resistance to Met inhibition and aggressive phenotypes

Purpose

Hepatocyte growth factor (HGF)/Met signaling plays critical roles in pancreatic ductal adenocarcinoma (PDA) development and progression and is considered a potential therapeutic target for this disease. However, the mechanism of aberrant activation of HGF/Met signaling and resistance to Met inhibition in PDA remains unclear.

Experimental Design

The mechanistic role of cross-talk between Forkhead box M1 (FOXM1) and HGF/Met signaling in promotion of PDA growth and resistance to Met inhibition was examined using cell culture, molecular biology and mouse models; and the relevance of our experimental and mechanistic findings were validated using human PDA tissues.

Results

Met was markedly overexpressed in both PDA cell lines and pancreatic tumor specimens, and the expression of Met correlated directly with that of FOXM1 in human tumor specimens. Mechanistically, FOXM1 bound to the promoter region of the Met gene and transcriptionally increased the expression of Met. Increased expression of FOXM1 enhanced the activation of HGF/Met signaling and its downstream pathways, including RAS/extracellular signal-regulated kinase 1/2, phosphoinositide 3-kinase/AKT, and signal transducer and activator of transcription 3. Furthermore, activation of HGF/Met signaling increased the expression and transcriptional activity of FOXM1, and the cross-talk between FOXM1 and HGF/Met signaling promoted PDA growth and resistance to Met inhibition.

Conclusions

Collectively, our findings identified a positive feedback loop formed by FOXM1 and HGF/Met and revealed that this loop is a potentially effective therapeutic target for PDA.

Laricitrin suppresses increased benzo(a)pyrene-induced lung tumor-associated monocyte-derived dendritic cell cancer progression

Benzo(a)pyrene (BaP) stimulates lung cancer cells, promoting monocyte-derived dendritic cells to secrete soluble factors, including heparin binding-epidermal growth factor and C-X-C motif chemokine 5. The secretions from monocyte-derived dendritic cells stimulate the progression of lung cancer cells, including the migration and invasion of cells. To the best of our knowledge, these secretions remain unknown, and require additional study. The present study identified that treatment with BaP-H1395-tumor-associated dendritic cell-conditioned medium had the most marked effect on cell migration and invasion. This result may be associated with the female gender, stage 2 adenocarcinoma or mutation of the proto-oncogene B-Raf (BRAF), according to the cell line background. Laricitrin, a dietary flavonoid derivative present in grapes and red wine, suppresses certain factors and decreases the progression of lung cancer cells that are promoted by BaP in the lung cancer tumor microenvironment. The results of the present study suggest that prolonged exposure to BaP exacerbates lung cancer, particularly in female lung cancer patients with the BRAF mutation, but that laricitrin may ameliorate this effect.

Epiregulin as a therapeutic target in non-small-cell lung cancer

Epiregulin (EREG) belongs to the ErbB family of ligands. EREG binds to EGFR and ErbB4 receptor and stimulates homodimers of EGFR and ErbB4 in addition to all possible heterodimeric ErbB complexes, resulting in the activation of downstream signaling pathways. EREG is overexpressed in various human cancers and has been implicated in tumor progression and metastasis. Oncogenic activation of the MEK/ERK pathway plays a central role in the regulation of EREG expression. Non-small-cell lung cancers (NSCLCs) harboring KRAS, BRAF, or EGFR mutations overexpress EREG, and abrogation of such mutations or inhibition of MEK or ERK downregulates the expression of EREG. Elevated EREG expression in NSCLC is associated with aggressive tumor phenotypes and unfavorable prognosis, especially in oncogenic KRAS-driven lung adenocarcinomas. The finding that attenuation of EREG inhibits cell growth and induces apoptosis in KRAS-mutant and EREG-overexpressing NSCLC cell lines suggests that targeting EREG might be a treatment option for KRAS-mutant NSCLC, although further studies are necessary to elucidate its therapeutic value. These observations suggest that oncogenic mutations in the EGFR, KRAS, or BRAF genes induce EREG upregulation through the activation of MEK/ERK pathway in NSCLC cells, whereas overproduced EREG stimulates the EGFR/ErbB receptors and activates multiple downstream signaling pathways, leading to tumor progression and metastasis of these oncogene-driven NSCLCs. This paper reviews the current understanding of the oncogenic role of EREG and highlights its potential as a therapeutic target for NSCLC.

Update in Lung Cancer 2014

In the past 2 years, lung cancer research and clinical care have advanced significantly. Advancements in the field have improved outcomes and promise to lead to further reductions in deaths from lung cancer, the leading cause of cancer death worldwide. These advances include identification of new molecular targets for personalized targeted therapy, validation of molecular signatures of lung cancer risk in smokers, progress in lung tumor immunotherapy, and implementation of population-based lung cancer screening with chest computed tomography in the United States. In this review, we highlight recent research in these areas and challenges for the future.

Epidermal growth factor receptor immunohistochemistry: new opportunities in metastatic colorectal cancer

The treatment of cancer is becoming more precise, targeting specific oncogenic drivers with targeted molecular therapies. The epidermal growth factor receptor has been found to be over-expressed in a multitude of solid tumours. Immunohistochemistry is widely used in the fields of diagnostic and personalised medicine to localise and visualise disease specific proteins. To date the clinical utility of epidermal growth factor receptor immunohistochemistry in determining monoclonal antibody efficacy has remained somewhat inconclusive. The lack of an agreed reproducible scoring criteria for epidermal growth factor receptor immunohistochemistry has, in various clinical trials yielded conflicting results as to the use of epidermal growth factor receptor immunohistochemistry assay as a companion diagnostic. This has resulted in this test being removed from the licence for the drug panitumumab and not performed in clinical practice for cetuximab. In this review we explore the reasons behind this with a particular emphasis on colorectal cancer, and to suggest a way of resolving the situation through improving the precision of epidermal growth factor receptor immunohistochemistry with quantitative image analysis of digitised images complemented with companion molecular morphological techniques such as in situ hybridisation and section based gene mutation analysis.

Gene expression markers of efficacy and resistance to cetuximab treatment in metastatic colorectal cancer: results from CALGB 80203 (Alliance)

PURPOSE

Formalin-fixed, paraffin-embedded tumor samples from CALGB 80203 were analyzed for expression of EGFR axis-related genes to identify prognostic or predictive biomarkers for cetuximab treatment.

PATIENTS AND METHODS

Patients (238 total) with first-line metastatic colorectal cancer (mCRC) were randomized to FOLFOX or FOLFIRI chemotherapy ± cetuximab. qRT-PCR analyses were conducted on tissues from 103 patients at baseline to measure gene expression levels of HER-related genes, including amphiregulin (AREG), betacellulin (BTC), NT5E (CD73), DUSP4, EGF, EGFR, epigen (EPGN), epiregulin (EREG), HBEGF, ERBB2 (HER2), ERBB3 (HER3), ERBB4 (HER4), PHLDA1, and TGFA. The interactions between expression levels and treatment with respect to progression-free survival (PFS) and overall survival (OS) were modeled using multiplicative Cox proportional hazards models.

RESULTS

High tumor mRNA levels of HER2 [hazard ratio (HR), 0.64; P = 0.002] and EREG (HR, 0.89; P = 0.016) were prognostic markers associated with longer PFS across all patients. HER3 and CD73 expression levels were identified as potential predictive markers of benefit from cetuximab. In KRAS wild-type (WT) tumors, low HER3 expression was associated with longer OS from cetuximab treatment, whereas high HER3 expression was associated with shorter OS from cetuximab treatment (chemo + cetuximab: HR, 1.15; chemo-only: HR, 0.48; Pinteraction = 0.029). High CD73 expression was associated with longer PFS from cetuximab treatment in patients with KRAS-WT (chemo + cetuximab: HR, 0.91; chemo-only: HR, 1.57; Pinteraction = 0.026) and KRAS-mutant (Mut) tumors (chemo + cetuximab: HR, 0.80; chemo-only: HR, 1.29; P = 0.025).

CONCLUSIONS

Gene expression of HER3 and CD73 was identified as a potential predictive marker for cetuximab. These data implicate HER axis signaling and immune modulation as potential mechanisms of cetuximab action and sensitivity.

Detection of ALK protein expression in lung squamous cell carcinomas by immunohistochemistry

Background

The echinoderm microtubule-associated protein-like 4 (EML4) gene and the anaplastic lymphoma kinase (ALK) gene rearrangements occur in approximately 5% of lung adenocarcimomas (ACA), leading to ALK overexpression and predicting response to targeted therapy. To the present, few studies have been focused on the expression of ALK protein in lung squamous cell carcinomas (SqCC). Only several cases of lung SqCC were reported expression of ALK protein. No clinical study has been published to explicit the relationship between ALK expression and the response to targeted therapy in SqCC.

Methods

In this study, we analyzed ALK protein expression with a specific rabbit monoclonal Ig antibody (D5F3 clone) in 207 cases of lung SqCC. The positive cases were confirmed with ALK fluorescence in situ hybridization (FISH) and RT-PCR.

Results

We found that 3 out of 207 (1.4%) cases of lung SqCC were ALK positive detected by IHC staining, which were confirmed by ALK FISH and RT-PCR.

Conclusions

Our results indicate that ALK protein expression is not a rare molecular event in SqCC. Although the frequency of EML4-ALK rearrangements is lower in lung SqCC than that in lung adenocarcinomas, their presence may provide additional treatment options in lung SqCC. The response of SqCC patients with ALK expression to target therapy of crizotinib should be explored.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-014-0109-2) contains supplementary material, which is available to authorized users.

Epidermal growth factor signaling in transformed cells

Members of the epidermal growth factor receptor (EGFR/ErbB) family play a critical role in normal cell growth and development. However, many ErbB family members, especially EGFR, are aberrantly expressed or deregulated in tumors and are thought to play crucial roles in cancer development and metastatic progression. In this chapter, we provide an overview of key mechanisms contributing to aberrant EGFR/ErbB signaling in transformed cells, which results in many phenotypic changes associated with the earliest stages of tumor formation, including several hallmarks of epithelial-mesenchymal transition (EMT). These changes often occur through interaction with other major signaling pathways important to tumor progression, causing a multitude of transcriptional changes that ultimately impact cell morphology, proliferation, and adhesion, all of which are crucial for tumor progression. The resulting mesh of signaling networks will need to be taken into account as new regimens are designed for targeting EGFR for therapeutic intervention. As new insights are gained into the molecular mechanisms of cross talk between EGFR signaling and other signaling pathways, including their roles in therapeutic resistance to anti-EGFR therapies, a continual reassessment of clinical therapeutic regimes and strategies will be required. Understanding the consequences and complexity of EGF signaling and how it relates to tumor progression is critical for the development of clinical compounds and establishing clinical protocols for the treatment of cancer.

Gefitinib resistance resulted from STAT3-mediated Akt activation in lung cancer cells

Hyperactivation of Epidermal Growth Factor Receptor (EGFR) tyrosine kinase is prevalent in human lung cancer and its inhibition by the tyrosine kinase inhibitors (TKIs), including gefitinib and erlotinib, initially controls tumor growth. However, most patients ultimately relapse due to the development of drug resistance. In this study, we have discovered a STAT3-dependent Akt activation that impairs the efficacy of gefitinib. Mechanistically, gefitinib increased association of EGFR with STAT3, which de-repressed STAT3 from SOCS3, an upstream suppressor of STAT3. Such a de-repression of STAT3 in turn fostered Akt activation. Genetic or pharmacological inhibition of STAT3 abrogated Akt activation and combined gefitinib with STAT3 inhibition synergistically reduced the growth of the tumor cells. Taken together, this study suggests that activation of STAT3 is an intrinsic mechanism of drug resistance in response to EGFR TKIs. Combinational targeting on both EGFR and STAT3 may enhance the efficacy of gefitinib or other EGFR TKIs in lung cancer.

Invasion pattern and histologic features of tumor aggressiveness correlate with MMR protein expression, but are independent of activating KRAS and BRAF mutations in CRC

KRAS/BRAF mutation testing and mismatch repair (MMR) protein immunohistochemistry have an established role in routine diagnostic evaluation of colorectal carcinoma (CRC). However, since the exact impact of these molecular characteristics on tumor morphology and behavior is still subject to research, the aim of our study was to examine associations between molecular and morphologic features that had not been analyzed in this combination before. KRAS (codons 12, 13, and 61) and BRAF (codon 600) mutation status and MMR protein expression were analyzed in a consecutive series of 117 CRC samples using DNA pyrosequencing and immunohistochemistry. Tumor cell budding, infiltration pattern, and peritumoral lymphocytic (PTL) reaction was assessed applying established criteria. Molecular and morphological findings were correlated applying chi-square and Fisher's exact test. We found KRAS or BRAF mutations in 40 and 8 % of samples, while loss of MMR protein expression was observed in 11 %. Tumor budding was significantly associated with infiltrative growth, absence of PTLs, and blood and lymph vessel infiltration. Neither KRAS nor BRAF mutations were associated with a certain growth pattern or budding intensity of CRC, but loss of MMR protein expression was found in context with BRAF mutation, expanding growth, and presence of PTLs. Our results confirm an association between loss of MMR protein expression, presence of activating BRAF mutation, expanding growth, and PTL reaction as well as between tumor budding, infiltrative growth pattern, and tumor aggressiveness; however, there was no such association between the presence of an activating KRAS or BRAF mutation and a distinct invasion pattern or tumor aggressiveness in CRC.