Mechanisms of resistance to EGFR targeted therapies

Tumor Microenvironment Modifications Induced by Afatinib in Squamous Cell Carcinoma of the Head and Neck: A Window-of-Opportunity Study (EORTC-90111-24111)

PURPOSE

The EORTC-90111-24111 phase II window study evaluated afatinib versus no preoperative treatment in patients with primary squamous cell carcinoma of the head and neck (HNSCC). We investigated afatinib-induced tumor and microenvironment modifications by comparing pre- and posttreatment tumor biopsies.

PATIENTS AND METHODS

Thirty treatment-naïve patients with primary HNSCC were randomized. Twenty-five patients received afatinib for 14 days before surgery (40 mg 1×/day) and 5 patients were attributed to the control arm. Biopsies were taken at work-up and during surgery. Good quality RNA samples were used for omics analyses. The control arm was enlarged by samples coming from our previous similar window study.

RESULTS

IHC analyses of afatinib-treated tumor biopsies showed a decrease in pEGFR (P ≤ 0.05) and pERK (P ≤ 0.05); and an increase in CD3+ (P ≤ 0.01) and CD8+ (P ≤ 0.01) T-cell infiltration, and in CD3+ (P ≤ 0.05) T-cell density. RNA sequencing analyses of afatinib-treated tumor samples showed upregulation of inflammatory genes and increased expression scores of signatures predictive of response to programmed cell death protein 1 blockade (P ≤ 0.05). In posttreatment biopsies of afatinib-treated patients, two clusters were observed. Cluster 1 showed a higher expression of markers and gene sets implicated in epithelial-to-mesenchymal transition (EMT) and activation of cancer-associated fibroblasts (CAF) compared with cluster 2 and controls.

CONCLUSIONS

Short-term treatment with afatinib in primary HNSCC induces CD3+ and CD8+ tumor infiltration and, in some patients, EMT and CAF activation. These results open perspectives to overcome resistance mechanisms to anti-HER therapy and to potentiate the activity of immune checkpoint inhibitors.

Design, synthesis and molecular docking study of new pyrimidine-based hydrazones with selective anti-proliferative activity against MCF-7 and MDA-MB-231 human breast cancer cell lines

Efforts were directed on the design, synthesis and evaluation of the anticancer activity of some pyrimidine-based hydrazones against two breast cancer cell lines, MCF-7 and MDA-MB-231. Preliminary screening results revealed that some candidates scrutinized for their antiproliferative activities exhibited IC50 values of 0.87 μM-12.91 μM in MCF-7 and 1.75 μM-9.46 μM in MDA-MB-231 cells, indicating almost equal activities on both cell lines and better growth inhibition activities than those of the positive control 5-fluorouracil (5-FU) which displayed IC50 values of 17.02 μM and 11.73 μM respectively. Selectivity of the significantly active compounds was estimated against MCF-10A normal breast cells when compounds 7c, 8b, 9a and 10b exhibited superior activity for cancerous cells than for normal cells when compound 10b presented the best selectivity Index (SI) with respect to both MCF-7 and MDA-MB-231 cancer cells in comparison to the reference drug 5-FU. Mechanisms of their actions were explored by inspecting activation of caspase-9, annexin V staining and cell cycle analysis. It was noticed that compounds 7c, 8b, 8c 9a-c and 10b produced an increase in caspase-9 levels in MCF-7 treated cells with 10b inducing the highest elevation (27.13 ± 0.54 ng/mL) attaining 8.26-fold when compared to control MCF-7 which was higher than that of staurosporine (19.011 ± 0.40 ng/mL). The same compounds boosted caspase-9 levels in MDA-MB-231 treated cells when an increase in caspase-9 concentration reaching 20.40 ± 0.46 ng/mL (4.11-fold increase) was observed for compound 9a. We also investigated the role of these compounds for their increasing apoptosis ability against the 2 cell lines. Compounds 7c, 8b and 10b tested on MCF-7 cells displayed pre-G1 apoptosis and arrested cell cycle in particular at the S and G1 phases. Further clarification of their effects was made by modulating their related activities as inhibitors of ARO and EGFR enzymes when 8c and 9b showed 52.4% and 58.9% inhibition activity relative to letrozole respectively and 9b and 10b showed 36% and 39% inhibition activity of erlotinib. Also, the inhibition activity was verified by docking into the chosen enzymes.

Nuclear epidermal growth factor receptor as a therapeutic target

Epidermal growth factor receptor (EGFR) is one of the most well-studied oncogenes with roles in proliferation, growth, metastasis, and therapeutic resistance. This intense study has led to the development of a range of targeted therapeutics including small-molecule tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and nanobodies. These drugs are excellent at blocking the activation and kinase function of wild-type EGFR (wtEGFR) and several common EGFR mutants. These drugs have significantly improved outcomes for patients with cancers including head and neck, glioblastoma, colorectal, and non-small cell lung cancer (NSCLC). However, therapeutic resistance is often seen, resulting from acquired mutations or activation of compensatory signaling pathways. Additionally, these therapies are ineffective in tumors where EGFR is found predominantly in the nucleus, as can be found in triple negative breast cancer (TNBC). In TNBC, EGFR is subjected to alternative trafficking which drives the nuclear localization of the receptor. In the nucleus, EGFR interacts with several proteins to activate transcription, DNA repair, migration, and chemoresistance. Nuclear EGFR (nEGFR) correlates with metastatic disease and worse patient prognosis yet targeting its nuclear localization has proved difficult. This review provides an overview of current EGFR-targeted therapies and novel peptide-based therapies that block nEGFR, as well as their clinical applications and potential for use in oncology.

BCA101 Is a Tumor-Targeted Bifunctional Fusion Antibody That Simultaneously Inhibits EGFR and TGFβ Signaling to Durably Suppress Tumor Growth

The EGFR and TGFβ signaling pathways are important mediators of tumorigenesis, and cross-talk between them contributes to cancer progression and drug resistance. Therapies capable of simultaneously targeting EGFR and TGFβ could help improve patient outcomes across various cancer types. Here, we developed BCA101, an anti-EGFR IgG1 mAb linked to an extracellular domain of human TGFβRII. The TGFβ "trap" fused to the light chain in BCA101 did not sterically interfere with its ability to bind EGFR, inhibit cell proliferation, or mediate antibody-dependent cellular cytotoxicity. Functional neutralization of TGFβ by BCA101 was demonstrated by several in vitro assays. BCA101 increased production of proinflammatory cytokines and key markers associated with T-cell and natural killer-cell activation, while suppressing VEGF secretion. In addition, BCA101 inhibited differentiation of naïve CD4+ T cells to inducible regulatory T cells (iTreg) more strongly than the anti-EGFR antibody cetuximab. BCA101 localized to tumor tissues in xenograft mouse models with comparable kinetics to cetuximab, both having better tumor tissue retention over TGFβ "trap." TGFβ in tumors was neutralized by approximately 90% in animals dosed with 10 mg/kg of BCA101 compared with 54% in animals dosed with equimolar TGFβRII-Fc. In patient-derived xenograft mouse models of head and neck squamous cell carcinoma, BCA101 showed durable response after dose cessation. The combination of BCA101 and anti-PD1 antibody improved tumor inhibition in both B16-hEGFR-expressing syngeneic mouse models and in humanized HuNOG-EXL mice bearing human PC-3 xenografts. Together, these results support the clinical development of BCA101 as a monotherapy and in combination with immune checkpoint therapy.

SIGNIFICANCE

The bifunctional mAb fusion design of BCA101 targets it to the tumor microenvironment where it inhibits EGFR and neutralizes TGFβ to induce immune activation and to suppress tumor growth.

Cooperation between Prostaglandin E2 and Epidermal Growth Factor Receptor in Cancer Progression: A Dual Target for Cancer Therapy

It is recognized that prostaglandin E2 (PGE2) is one key lipid mediator involved in chronic inflammation, and it is directly implicated in tumor development by regulating cancer cell growth and migration, apoptosis, epithelial-mesenchymal transition, angiogenesis, and immune escape. In addition, the expression of the enzymes involved in PGE2 synthesis, cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase 1 (mPGES1), positively correlates with tumor progression and aggressiveness, clearly indicating the crucial role of the entire pathway in cancer. Moreover, several lines of evidence suggest that the COX2/mPGES1/PGE2 inflammatory axis is involved in the modulation of epidermal growth factor receptor (EGFR) signaling to reinforce the oncogenic drive of EGFR activation. Similarly, EGFR activation promotes the induction of COX2/mPGES1 expression and PGE2 production. In this review, we describe the interplay between COX2/mPGES1/PGE2 and EGFR in cancer, and new therapeutic strategies that target this signaling pathway, to outline the importance of the modulation of the inflammatory process in cancer fighting.

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Introduction: Cancer stem cells (CSC), a major culprit of drug-resistant phenotypes and tumor relapse, represent less than 2 % of the bulk of TNBC cells, making them difficult to isolate, study, and thus, limiting our understanding of the pathogenesis of the disease. Current methods for CSC enrichment, such as 3D spheroid culture, genetic modification, and stem cell conditioning, are time consuming, expensive, and unsuitable for high-throughput assays. One way to address these limitations is to use topographical stimuli to enhance CSC populations in planar culture. Physical cues in the breast tumor microenvironment can influence cell behavior through changes in the mechanical properties of the extracellular matrix (ECM). In this study, we used topographical cues on polystyrene films to investigate their effect on the proteome and stemness of standard TNBC cell lines. Methods: The topographical polystyrene-based array was generated using razor printing and polishing methods. Proteome data were analyzed and enriched bioprocesses were identified using R software. Stemness was assessed measuring CD44, CD24 and ALDH markers using flow cytometry, immunofluorescence, detection assays, and further validated with mammosphere assay. EGF/EGFR expression and activity was evaluated using enzyme-linked immunosorbent assay (ELISA), immunofluorescence and antibody membrane array. A dose-response assay was performed to further investigate the effect of surface topography on the sensitivity of cells to the EGFR inhibitor. Results: Surface roughness enriched the CSC population and modulated epidermal growth factor receptor (EGFR) signaling activity in TNBC cells. Enhanced proliferation of MDA-MB-468 cells in roughness correlated with upregulation of the epidermal growth factor (EGF) ligand, which in turn corresponded with a 3-fold increase in the expression of EGFR and a 42% increase in its phosphorylation compared to standard smooth culture surfaces. The results also demonstrated that phenotypic changes associated with topographical (roughness) stimuli significantly decreased the drug sensitivity to the EGFR inhibitor gefitinib. In addition, the proportion of CD44+/CD24-/ALDH+ was enhanced on surface roughness in both MDA-MB-231 and MDA-MB-468 cell lines. We also demonstrated that YAP/TAZ activation decreased in a roughness-dependent manner, confirming the mechanosensing effect of the topographies on the oncogenic activity of the cells. Discussion: Overall, this study demonstrates the potential of surface roughness as a culture strategy to influence oncogenic activity in TNBC cells and enrich CSC populations in planar cultures. Such a culture strategy may benefit high-throughput screening studies seeking to identify compounds with broader tumor efficacy.

Evaluation of the Mechanism of Jiedu Huazhuo Quyu Formula in Treating Wilson's Disease-Associated Liver Fibrosis by Network Pharmacology Analysis and Molecular Dynamics Simulation

The Jiedu Huazhuo Quyu formula (JHQ) shows significant beneficial effects against liver fibrosis caused by Wilson's disease (WD). Hence, this study aimed to clarify the mechanisms of the JHQ treatment in WD-associated liver fibrosis. First, we collected 103 active compounds and 527 related targets of JHQ and 1187 targets related to WD-associated liver fibrosis from multiple databases. Next, 113 overlapping genes (OGEs) were obtained. Then, we built a protein-protein interaction (PPI) network with Cytoscape 3.7.2 software and performed the Gene Ontology (GO) term and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analyses with GENE DENOVO online sites. Furthermore, module analysis was performed, and the core target genes in the JHQ treatment of WD-associated liver fibrosis were obtained. Pathway and functional enrichment analyses, molecular docking studies, molecular dynamic (MD) simulation, and Western blot (WB) were then performed. The results indicated that 8 key active compounds including quercetin, luteolin, and obacunone in JHQ might affect the 6 core proteins including CXCL8, MAPK1, and AKT1 and 107 related signaling pathways including EGFR tyrosine kinase inhibitor resistance, Kaposi sarcoma-associated herpesvirus infection, and human cytomegalovirus infection signaling pathways to exhibit curative effects on WD-associated liver fibrosis. Mechanistically, JHQ might inhibit liver inflammatory processes and vascular hyperplasia, regulate the cell cycle, and suppress both the activation and proliferation of hepatic stellate cells (HSCs). This study provides novel insights for researchers to systematically explore the mechanism of JHQ in treating WD-associated liver fibrosis.

ARID1A serves as a receivable biomarker for the resistance to EGFR-TKIs in non-small cell lung cancer

ARID1A is a key component of the SWI/SNF chromatin remodeling complexes which is important for the maintaining of biological processes of cells. Recent studies had uncovered the potential role of ARID1A alterations or expression loss in the therapeutic sensitivity of cancers, but the studies in this field requires to be further summarized and discussed. Therefore, we proposed a series of mechanisms related to the resistance to EGFR-TKIs induced by ARID1A alterations or expression loss and the potential therapeutic strategies to overcome the resistance based on published studies. It suggested that ARID1A alterations or expression loss might be the regulators in PI3K/Akt, JAK/STAT and NF-κB signaling pathways which are strongly associated with the resistance to EGFR-TKIs in NSCLC patients harboring sensitive EGFR mutations. Besides, ARID1A alterations or expression loss could lead to the resistance to EGFR-TKIs via a variety of processes during the tumorigenesis and development of cancers, including epithelial to mesenchymal transition, angiogenesis and the inhibition of apoptosis. Based on the potential mechanisms related to ARID1A, we summarized that the small molecular inhibitors targeting ARID1A or PI3K/Akt pathway, the anti-angiogenic therapy and immune checkpoint inhibitors could be used for the supplementary treatment for EGFR-TKIs among NSCLC patients harboring the concomitant alterations of sensitive EGFR mutations and ARID1A.

Current Aspects and Future Considerations of EGFR Inhibition in Locally Advanced and Recurrent Metastatic Squamous Cell Carcinoma of the Head and Neck

Simple Summary

Squamous cell carcinoma of the head and neck (SCCHN) is a debilitating disease that affects hundreds of thousands of individuals worldwide and has a high mortality rate. Mainstay treatment largely consists of surgery, radiation, and chemotherapy which has been met with significant morbidity. The epidermal growth factor receptor is one that which plays a major role in cell signaling and has been extensively studied in locally advanced (LA) and recurrent metastatic (RM) SCCHN. This review paper details the major roles of the epidermal growth factor receptor (EGFR), previous and current EGFR inhibition therapeutics, resistance mechanisms, and the possible integration of immunotherapy and EGFR inhibition in this disease process.

Abstract

Recurrent metastatic (RM) and locally advanced (LA) squamous cell carcinoma of the head and neck (SCCHN) are devasting disease states with limited therapeutic options and poor overall survival. Targeting the epidermal growth factor receptor (EGFR) is one area that has helped improve outcomes in this disease. Anti-EGFR based therapies have been shown to improve overall survival and mitigate the significant toxicities incurred from standard radiation, chemotherapy, and/or surgical options. Cetuximab, the most well-studied anti-EGFR monoclonal antibody, has demonstrated a positive impact on outcomes for RM and LA SCCHN. However, the development of early resistance to cetuximab highlights the need for a wider arsenal of therapy for RM and LA diseases. The use of immune checkpoint inhibitors has recently transformed the treatment of recurrent SCCHN. Drugs such as pembrolizumab and nivolumab have demonstrated success in recent clinical trials and have been approved for the treatment of advanced disease. Given the positive results of both EGFR targeted agents and immune checkpoint inhibitors, ongoing trials are studying their synergistic effects.

mTOR-Rictor-EGFR axis in oncogenesis and diagnosis of glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the aggressive brain cancers with patients having less survival period upto 12-15 months. Mammalian target of rapamycin (mTOR) is a serine/threonine kinase, belongs to the phosphatidylinositol 3-kinases (PI3K) pathway and is involved in various cellular processes of cancer cells. Cancer metabolism is regulated by mTOR and its components. mTOR forms two complexes as mTORC1 and mTORC2. Studies have identified the key component of the mTORC2 complex, Rapamycin-insensitive companion of mammalian target of rapamycin (Rictor) plays a prominent role in the regulation of cancer cell proliferation and metabolism. Apart, growth factor receptor signaling such as epidermal growth factor signaling mediated by epidermal growth factor receptor (EGFR) regulates cancer-related processes. In EGFR signaling various other signaling cascades such as phosphatidyl-inositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR pathway) and Ras/Raf/mitogen-activated protein kinase/ERK kinase (MEK)/extracellular-signal-regulated kinase (ERK) -dependent signaling cross-talk each other. From various studies about GBM, it is very well established that Rictor and EGFR mediated signaling pathways majorly playing a pivotal role in chemoresistance and tumor aggressiveness. Recent studies have shown that non-coding RNAs such as microRNAs (miRs) and long non-coding RNAs (lncRNAs) regulate the EGFR and Rictor and sensitize the cells towards chemotherapeutic agents. Thus, understanding of microRNA mediated regulation of EGFR and Rictor will help in cancer prevention and management as well as a future therapy.

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

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

Mesenchymal stem cells promote metastasis through activation of an ABL-MMP9 signaling axis in lung cancer cells

Mesenchymal stem cells (MSCs) are recruited and activated by solid tumors and play a role in tumor progression and metastasis. Here we show that MSCs promote metastasis in a panel of non-small cell lung cancer (NSCLC) cells. MSCs elicit transcriptional alterations in lung cancer cells leading to increased expression of factors implicated in the epithelial-to-mesenchymal transition (EMT) and secreted proteins including matrix metalloproteinase-9 (MMP9). MSCs enhance secretion of enzymatically active MMP9 in a panel of lung adenocarcinoma cells. High expression of MMP9 is linked to low survival rates in lung adenocarcinoma patients. Notably, we found that ABL tyrosine kinases are activated in MSC-primed lung cancer cells and functional ABL kinases are required for MSC-induced MMP9 expression, secretion and proteolytic activity. Importantly, ABL kinases are required for MSC-induced NSCLC metastasis. These data reveal an actionable target for inhibiting MSC-induced metastatic activity of lung adenocarcinoma cells through disruption of an ABL kinase-MMP9 signaling axis activated in MSC-primed lung cancer cells.

PDGFD induces ibrutinib resistance of diffuse large B‑cell lymphoma through activation of EGFR

Ibrutinib, an FDA approved, orally administered BTK inhibitor, has demonstrated high response rates to diffuse large B-cell lymphoma (DLBCL), however, complete responses are infrequent and acquired resistance to BTK inhibition can emerge. The present study investigated the role of the platelet-derived growth factor D (PDGFD) gene and the ibrutinib resistance of DLBCL in relation to epidermal growth factor receptor (EGFR). Bioinformatics was used to screen and analyze differentially expressed genes (DEGs) in complete response (CR), partial response (PR) and stable disease (SD) in DLBCL treatment with ibrutinib, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to analyze enriched the signaling pathways increasing DEGs. The Search Tool for Interactions of Chemicals database was used to analyze the target genes of ibrutinib. An interaction network of DEGs, disease-related genes and ibrutinib was constructed. The expression of PDGFD in tissues that were resistant or susceptible to DLBCL/ibrutinib was detected via immunohistochemistry (IHC), and the expression of PDGFD in DLBCL/ibrutinib-resistant strains and their parental counterparts were examined via reverse transcription-quantitative PCR and western blot analyses. Subsequently, a drug-resistant cell model of DLBCL/ibrutinib in which PDGFD was silenced was constructed. The apoptosis of the DLBCL/ibrutinib-resistant strains was examined using MTT and flow cytometry assays. EGFR gene expression was then assessed. At the same time, a PDGFD-interfering plasmid and an EGFR overexpression plasmid were transfected into the DLBCL drug-resistant cells (TMD8-ibrutinib, HBL1-ibrutinib) separately or together. MTT was used to measure cell proliferation and changes in the IC₅₀ of ibrutinib. A total of 86 DEGs that increased in the CR, PR and SD tissues were screened, and then evaluated with GO and KEGG. The interaction network diagram showed that there was a regulatory relationship between PDGFD and disease-related genes, and that PDGFD could indirectly target the ibrutinib target gene EGFR, indicating that PDGFD could regulate DLBCL via EGFR. IHC results showed high expression of PDGFD in diffuse large B-cell lymphoma tissues with ibrutinib tolerance. PDGFD expression in ibrutinib-resistant DLBCL cells was higher compared with in parental cells. Following interference with PDGFD expression in ibrutinib-resistant DLBCL cells, the IC₅₀ value of ibrutinib decreased, the rate of apoptosis increased and EGFR expression decreased. In brief, EGFR overexpression can reverse the resistance of DLBCL to ibrutinib via PDGFD interference, and PDGFD induces the resistance of DLBCL to ibrutinib via EGFR.

Model-based analysis of response and resistance factors of cetuximab treatment in gastric cancer cell lines

Targeted cancer therapies are powerful alternatives to chemotherapies or can be used complementary to these. Yet, the response to targeted treatments depends on a variety of factors, including mutations and expression levels, and therefore their outcome is difficult to predict. Here, we develop a mechanistic model of gastric cancer to study response and resistance factors for cetuximab treatment. The model captures the EGFR, ERK and AKT signaling pathways in two gastric cancer cell lines with different mutation patterns. We train the model using a comprehensive selection of time and dose response measurements, and provide an assessment of parameter and prediction uncertainties. We demonstrate that the proposed model facilitates the identification of causal differences between the cell lines. Furthermore, our study shows that the model provides predictions for the responses to different perturbations, such as knockdown and knockout experiments. Among other results, the model predicted the effect of MET mutations on cetuximab sensitivity. These predictive capabilities render the model a basis for the assessment of gastric cancer signaling and possibly for the development and discovery of predictive biomarkers.

Unraveling the causal differences between drug responders and non-responders is an important challenge. The information can help to understand molecular mechanisms and to guide the selection and design of targeted therapies. Here, we approach this problem for cetuximab treatment for gastric cancer using mechanistic mathematical modeling. The proposed model describes responder and non-responder gastric cancer cell lines and can predict the response in several validation experiments. Our analysis provides a differentiated view on mutations and explains, for instance, the relevance of MET mutations and the insignificance of PIK3CA mutation in the considered cell lines. The model might potentially provide the basis for understanding the recent failure of several clinical studies.

A Proteomic Connectivity Map for Characterizing the Tumor Adaptive Response to Small Molecule Chemical Perturbagens

A powerful means to understand the cellular function of corrupt oncogenic signaling programs requires perturbing the system and monitoring the downstream consequences. Here, using a unique pair of non-small cell lung cancer (NSCLC)/normal lung epithelial patient-derived cell lines (HCC4017/HBEC30KT), we systematically interrogated the remodeling of the NSCLC proteome upon treatment with 35 chemical perturbagens targeting a diverse array of mechanistic classes. HCC4017 and HBEC30KT cells differ significantly in their proteomic response to the same compound treatment. Using protein covariance analyses, we identified a large number of functional protein networks. For example, we found that a poorly studied protein, C5orf22, is a novel component of the WBP11/PQBP1 splicing complex. Depletion of C5orf22 leads to the aberrant splicing and expression of genes involved in cell growth and immunomodulation. In summary, we show that by systematically measuring the tumor adaptive responses at the proteomic level, an understanding could be generated that provides critical circuit-level biological insights for these pharmacologic perturbagens.

Factors Associated With Distant Metastasis in EGFR-mutated Non-small Cell Lung Cancer Patients: Logistic Analysis

BACKGROUND/AIM

The aim of this retrospective study was to identify, using logistic analysis, the factors associated with distant metastasis in non-small cell lung cancer patients carrying mutations in epidermal growth factor receptor.

PATIENTS AND METHODS

Patients who were diagnosed with distant metastasis at the time of diagnosis up to their death and during the period from April 2009 to March 2019, were included in this study. Clinical charts and imaging studies were reviewed.

RESULTS

A total of 64 patients during the research period. The factors associated with pleural metastasis were "female" and "no bone metastasis". The factor associated with brain metastasis was "lung metastasis". The factors associated with liver metastasis were "age under 70" and "Exon 19 deletion".

CONCLUSION

Knowing the factors associated with distant metastasis will provide useful information to conduct targeted and efficient imaging studies.

Transglutaminase 2 induces intrinsic EGFR-TKI resistance in NSCLC harboring EGFR sensitive mutations

The non-small cell lung cancer (NSCLC) patients with EGFR-sensitive mutations can be therapeutically treated by EGFR-TKI such as erlotinib and gefitinib. However, about 40% of individuals harboring EGFR-TKI sensitive mutations are still resistant to EGFR-TKI. And, it has been reported that both PTEN loss and NF-κB activation contribute to intrinsic EGFR-TKI resistance in EGFR-mutant lung cancer. Transglutaminse 2 (TG2) is post-translational modification enzyme and known to induce degradation of tumor suppressors including PTEN and IκBα with peptide cross-linking activity. Because TG2 was known as a regulator of PTEN and IκBα (NF-κB inhibitor) level in cytosol, we have explored if TG2 can be another key regulator to the intrinsic resistance of EGFR-TKI in the intrinsic EGFR-TKI resistant NSCLC cell. We first found that higher TG2 expression level and lower PTEN and IκBα expression levels in the intrinsic EGFR-TKI resistant NSCLC compare with EGFR-TKI sensitive NSCLC. TG2 stably expressing EGFR-TKI sensitive NSCLC cells harboring EGFR mutations showed reduction of both PTEN and IκBα and exhibited EGFR-TKI resistance. In reverse, When TG2 is downregulated by TG2 inhibitor in H1650, intrinsic EGFR-TKI resistant NSCLC cell harboring EGFR sensitive mutation, reversed EGFR-TKI resistance via IκBα restoration. Moreover, combination treatment of TG2 inhibitor and EGFR-TKI decreased the tumor growth in mouse xenograft models of EGFR mutant NSCLCs. Therefore, we have demonstrated that TG2 elicits the intrinsic EGFR-TKI resistance via PTEN loss and activation of NF-κB pathway. These results suggest that TG2 may be a useful predictive marker and also be a target for overcoming the resistance.

Glucocorticoid Receptor Modulates EGFR Feedback upon Acquisition of Resistance to Monoclonal Antibodies

Evidences of a crosstalk between Epidermal Growth Factor Receptor (EGFR) and Glucocorticoid Receptor (GR) has been reported, ranging from the modulation of receptor levels or GR mediated transcriptional repression of EGFR target genes, with modifications of epigenetic markers. The present study focuses on the involvement of EGFR positive and negative feedback genes in the establishment of cetuximab (CTX) resistance in metastatic Colorectal Cancer (CRC) patients. We evaluated the expression profile of the EGFR ligands TGFA and HBEGF, along with the pro-inflammatory cytokines IL-1B and IL-8, which were previously reported to be negatively associated with monoclonal antibody response, both in mice and patient specimens. Among EGFR negative feedback loops, we focused on ERRFI1, DUSP1, LRIG3, and LRIG1. We observed that EGFR positive feedback genes are increased in CTX-resistant cells, whereas negative feedback genes are reduced. Next, we tested the expression of these genes in CTX-resistant cells upon GR modulation. We unveiled that GR activation leads to an increase in ERRFI1, DUSP1, and LRIG1, which were shown to restrict EGFR activity, along with a decrease in the EGFR activators (TGFA and IL-8). Finally, in a cohort of xenopatients, stratified for response to cetuximab, we observed an inverse association between the expression level of LRIG1 and CRC progression upon CTX treatment. Our model implies that combining GR modulation to EGFR inhibition may yield an effective treatment strategy in halting cancer progression.

Schizandrin A enhances the efficacy of gefitinib by suppressing IKKβ/NF-κB signaling in non-small cell lung cancer

The emergence of resistance to EGF receptor (EGFR) inhibitor therapy is a significant challenge for patients with non-small cell lung cancer (NSCLC). During the past few years, a correlation between EGFR TKIs resistance and dysregulation of IKKβ/NF-κB signaling has been increasingly suggested. However, few studies have focused on the effects of combining IKK/NF-κB and EGFR inhibitors to overcome EGFR TKIs resistance. In this study, we discovered that Schizandrin A (Sch A), a lignin compound isolated from Schisandra chinesnesis, could synergize with the EGFR receptor inhibitor Gefitinib to inhibit cell growth, induce cell cycle arrest and apoptosis of HCC827/GR cells. Sch A effectively suppressed the phosphorylation of IKKβ and IκBα, as well as the nuclear translocation of NF-κB p65, and showed high and selective affinity for IKKβ in surface plasmon resonance (SPR) experiments, indicating that Sch A was a selective IKKβ inhibitor. Molecular modeling between IKKβ and Sch A suggested that Sch A formed key hydrophobic interactions with IKKβ, which may contribute to its potent IKKβ inhibitory effect. These findings suggest a novel approach to improve poor clinical outcomes in EGFR TKIs therapy, by combining it with Sch A.

Molecular Profiling of Druggable Targets in Clear Cell Renal Cell Carcinoma Through Targeted RNA Sequencing

Clear cell renal cell carcinoma (ccRCC) comprises more than 80% of all renal cancers and when metastasized leads to a 5-year survival rate of only 10%. The high rate of therapy failure and resistance development calls for reliable methods that provide information on the actionable biological pathways and predict optimal treatment protocols for individual patients. We here applied targeted RNA sequencing (t/RNA-NGS) using single molecule Molecular Inversion Probes on tumor nephrectomy samples of five ccRCC patients, comparing tumor with healthy kidney tissues. Transcriptome profiling focused on expression of genes with involvement in ccRCC biology that can be targeted with clinically available drugs. Results confirm high expression of vascular endothelial growth factor-A (VEGF-A) in tumor tissue relative to healthy-appearing kidney, in line with the angiogenic nature of ccRCC. PDGFRα and KIT, targets of the multi-kinase inhibitor sunitinib which is one of the current choices of first-line drug in metastasized ccRCC patients, were expressed at relatively low levels in tumor tissues, whereas significantly increased in normal kidney. Of all measured druggable tyrosine kinases, MET, AXL, or EGFR were expressed at higher levels in tumors than in normal kidney tissues, although intertumor differences were observed. Using cancer cell lines we show that t/RNA-NGS gene expression profiles can be used to predict in vitro sensitivity to targeted drugs. In conclusion, t/RNA-NGS analysis may provide insights into the (druggable) molecular make-up of individual renal cancers, and may guide personalized therapy of renal cell cancers.

A large scale proteome analysis of the gefitinib primary resistance overcome by KDAC inhibition in KRAS mutated adenocarcinoma cells overexpressing amphiregulin

KDAC inhibitors (KDACi) overcome gefitinib primary resistance in non-small cell lung cancer (NSCLC) including mutant-KRAS lung adenocarcinoma. To identify which proteins are involved in the restoration of this sensitivity and to provide new therapeutic targets for mutant-KRAS lung adenocarcinoma, we performed an iTRAQ quantitative proteomic analysis after subcellular fractionation of H358-NSCLC treated with gefitinib and KDACi (TSA/NAM) versus gefitinib alone. The 86 proteins found to have been significantly dysregulated between the two conditions, were mainly involved in cellular metabolism and cell transcription processes. As expected, the pathway related to histone modifications was affected by the KDACi. Pathways known for controlling tumor development and (chemo)-resistance (miRNA biogenesis/glutathione metabolism) were affected by the KDACi/gefitinib treatment. Moreover, 57 dysregulated proteins were upstream of apoptosis (such as eEF1A2 and STAT1) and hence provide potential therapeutic targets. The inhibition by siRNA of eEF1A2 expression resulted in a slight decrease in H358-NSCLC viability. In addition, eEF1A2 and STAT1 siRNA transfections suggested that both STAT1 and eEF1A2 prevent AKT phosphorylation known for enhancing gefitinib resistance in NSCLC. Therefore, altogether our data provide new insights into proteome regulations in the context of overcoming the NSCLC resistance to gefitinib through KDACi in H358 KRAS mutated and amphiregulin-overexpressing NSCLC cells.

USP17 is required for trafficking and oncogenic signaling of mutant EGFR in NSCLC cells

Background

The deubiquitinase USP17 is overexpressed in NSCLC and has been shown to be required for the growth and motility of EGFR wild-type (WT) NSCLC cells. USP17 is also required for clathrin-mediated endocytosis of EGFR. Here, we examine the impact of USP17 depletion on the growth, as well as EGFR endocytosis and signaling, of EGFR mutant (MT) NSCLC cells. In particular, we examine NSCLC cells harboring an EGFR activating exon 19 deletion (HCC827), or both the L858R activating mutation and the T790M resistance gatekeeper mutation (H1975) which renders them resistant to EGFR tyrosine kinase inhibitors (TKIs).

Methods

MTT, trypan blue and clonogenic assays, confocal microscopy, Western blotting and cell cycle analysis were performed.

Results

USP17 depletion blocks the growth of EGFRMT NSCLC cells carrying either the EGFR exon 19 deletion, or L858R/T790M double mutation. In contrast to EGFRWT cells, USP17 depletion also triggers apoptosis of EGFRMT NSCLC cells. USP17 is required for clathrin-mediated endocytosis in these EGFRMT NSCLC cells, but it is not required for the internalization of the mutated EGFR receptors. Instead, USP17 depletion alters the localization of these receptors within the cell, and although it does not decrease basal EGFR activation, it potently reduces activation of Src, a key kinase in mutant EGFR-dependent tumorigenicity. Finally, we demonstrate that USP17 depletion can trigger apoptosis in EGFRWT NSCLC cells, when combined with the EGFR tyrosine kinase inhibitor (TKI) gefitinib.

Conclusions

Our data reveals that USP17 facilitates trafficking and oncogenic signaling of mutant EGFR and indicates targeting USP17 could represent a viable therapeutic strategy in NSCLC tumours carrying either an EGFR activating mutation, or a resistance gatekeeper mutation.

Discovery and Therapeutic Exploitation of Mechanisms of Resistance to MET Inhibitors in Glioblastoma

PURPOSE

Glioblastoma (GBM) is the most common and most lethal primary malignant brain tumor. The receptor tyrosine kinase MET is frequently upregulated or overactivated in GBM. Although clinically applicable MET inhibitors have been developed, resistance to single modality anti-MET drugs frequently occurs, rendering these agents ineffective. We aimed to determine the mechanisms of MET inhibitor resistance in GBM and use the acquired information to develop novel therapeutic approaches to overcome resistance.Experimental Design: We investigated two clinically applicable MET inhibitors: crizotinib, an ATP-competitive small molecule inhibitor of MET, and onartuzumab, a monovalent monoclonal antibody that binds to the extracellular domain of the MET receptor. We developed new MET inhibitor-resistant cells lines and animal models and used reverse phase protein arrays (RPPA) and functional assays to uncover the compensatory pathways in MET inhibitor-resistant GBM.

RESULTS

We identified critical proteins that were altered in MET inhibitor-resistant GBM including mTOR, FGFR1, EGFR, STAT3, and COX-2. Simultaneous inhibition of MET and one of these upregulated proteins led to increased cell death and inhibition of cell proliferation in resistant cells compared with either agent alone. In addition, in vivo treatment of mice bearing MET-resistant orthotopic xenografts with COX-2 or FGFR pharmacological inhibitors in combination with MET inhibitor restored sensitivity to MET inhibition and significantly inhibited tumor growth.

CONCLUSIONS

These data uncover the molecular basis of adaptive resistance to MET inhibitors and identify new FDA-approved multidrug therapeutic combinations that can overcome resistance.

MHC class I presented antigens from malignancies: A perspective on analytical characterization & immunogenicity

The field of cancer immunotherapy has expanded rapidly in the past few years, with many new approaches entering the clinic for T cell mediated killing of tumors. Several of these clinical approaches involve the exploitation of a CD8 + T cell response against MHC I presented tumor antigens. Here, we describe the types of tumor antigens which are considered as targets in the design of T cell based therapeutic approaches, the rationale for targeting MHC I antigens and the analytical tools commonly employed for the discovery of MHC I presented peptides. The advantages and disadvantages of each approach are discussed and a perspective on the future directions of the MHC I peptide exploration field and biotherapeutic strategies is given. SIGNIFICANCE: This work is the first time a review article has been written to summarize all the various types of tumor antigens, and the analytical tools employed to discover and characterize them.

A module of inflammatory cytokines defines resistance of colorectal cancer to EGFR inhibitors

Epidermal Growth Factor Receptor (EGFR) activates a robust signalling network to which colon cancer tumours often become addicted. Cetuximab, one of the monoclonal antibodies targeting this pathway, is employed to treat patients with colorectal cancer. However, many patients are intrinsically refractory to this treatment, and those who respond develop secondary resistance along time. Mechanisms of cancer cell resistance include either acquisition of new mutations or non genomic activation of alternative signalling routes. In this study, we employed a colon cancer model to assess potential mechanisms driving resistance to cetuximab. Resistant cells displayed increased ability to grow in suspension as colonspheres and this phenotype was associated with poorly organized structures. Factors secreted from resistant cells were causally involved in sustaining resistance, indeed administration to parental cells of conditioned medium collected from resistant cells was sufficient to reduce cetuximab efficacy. Among secreted factors, we report herein that a signature of inflammatory cytokines, including IL1A, IL1B and IL8, which are produced following EGFR pathway activation, was associated with the acquisition of an unresponsive phenotype to cetuximab in vitro. This signature correlated with lack of response to EGFR targeting also in patient-derived tumour xenografts. Collectively, these results highlight the contribution of inflammatory cytokines to reduced sensitivity to EGFR blockade and suggest that inhibition of this panel of cytokines in combination with cetuximab might yield an effective treatment strategy for CRC patients refractory to anti-EGFR targeting.

FLNa negatively regulated proliferation and metastasis in lung adenocarcinoma A549 cells via suppression of EGFR

Filamin A (FLNa) is a ubiquitously expressed cytoplasmic protein, which composes of an N-terminal actin binding domain (ABD) followed by 24 Ig-like repeats. FLNa functions as a cytoskeletal protein that links transmembrane receptors, including integrins, to F-actin and serves as a signaling intermediate. Recent studies have identified FLNa as a scaffold protein that interacts with over 90 proteins and plays vital roles in cellular signaling transduction. Mutations or defects in human FLNa gene have been shown to cause numerous developmental defects. Moreover, aberrant expression of FLNa has been observed in many cancers, such as parathyroid tumor, cervical cancer, and breast cancer. However, its role in lung adenocarcinoma has seldom been discussed. In the present study, our in vitro and in vivo studies demonstrated that silencing FLNa expression in lung cancer cell line A549 cells promoted proliferation, migration, and invasiveness of A549 cells by enhancing the activation of epidermal growth factor receptor and ERK signaling pathway. These results shed light on novel functions of FLNa in lung cancer and uncovered novel mechanisms, these results provided possible targets for the prediction and treatment for lung adenocarcinoma.

Integrated genomic approaches identify upregulation of SCRN1 as a novel mechanism associated with acquired resistance to erlotinib in PC9 cells harboring oncogenic EGFR mutation

Therapies targeting the tyrosine kinase activity of Epidermal Growth Factor Receptor (EGFR) have been proven to be effective in treating a subset of non-small cell lung cancer (NSCLC) patients harboring activating EGFR mutations. Inevitably these patients develop resistance to the EGFR-targeted tyrosine kinase inhibitors (TKIs). Here, we performed integrated genomic analyses using an in vitro system to uncover alternative genomic mechanisms responsible for acquired resistance to EGFR-TKIs. Specifically, we identified 80 genes whose expression is significantly increased in the erlotinib-resistant clones. RNAi-based systematic synthetic lethal screening of these candidate genes revealed that suppression of one upregulated transcript, SCRN1, a secernin family member, restores sensitivity to erlotinib by enhancing inhibition of PI3K/AKT signaling pathway. Furthermore, immunohistochemical analysis revealed increased levels of SCRN1 in 5 of 11 lung tumor specimens from EGFR-TKIs resistant patients. Taken together, we propose that upregulation of SCRN1 is an additional mechanism associated with acquired resistance to EGFR-TKIs and that its suppression serves as a novel therapeutic strategy to overcome drug resistance in these patients.

EGFR and Cortactin: Markers for potential double target therapy in oral squamous cell carcinoma

Survival periods of patients following surgical therapy of oral squamous cell carcinoma (OSCC) have previously been demonstrated to decrease over recent decades. Epidermal growth factor receptor (EGFR) and Cortactin are molecular markers that are important in tumour progression and development, and interact within the EGF pathway. Although EGFR antibody therapy exists, sufficient efforts for increased survival are still lacking due to the present limited response rates. The aim of the present study was to examine the association between EGFR and Cortactin expression on survival rates of OSCC patients and to determine whether EGFR and Cortactin expression levels are associated with advanced tumor sizes and lymphnode-metastases. In total, 222 OSCC patients were included in the study. EGFR and Cortactin expression in tumor tissue was evaluated by immunohistochemistry. Cox regression was used for survival analysis. Categories were tested for associations by using cross tabs (Chi-square test). Groups were compared by the non-parametric Mann Whitney U-test. Probabilities of less than 0.05 were considered significant and significant expression of Cortactin was observed in Advanced Union Internationale Contre le Cancer stage (P=0.032), including advanced tumour stage (P=0.021) and lymph node metastasis (P=0.049). High Cortactin expression was significantly associated with poorer survival rates (P=0.037). Further Cortactin expression was not associated with extracapsular spread, however EGFR exhibited a significant association (P=0.034). Neither EGFR nor Cortactin expression was correlated to grading. EGFR and Cortactin co-expression was demonstrated to be significantly associated with poorer survival rates in OSCC patients, suggesting that identification of predictive biomarkers for adjuvant therapies are of primary concern in OSCC. In particular, efficient dual-target therapy may act as an appropriate therapy to improve survival time for patients at advanced OSCC tumor stages.

Prognostic value of plasma EGFR ctDNA in NSCLC patients treated with EGFR-TKIs

OBJECTIVE

Epidermal growth factor receptor (EGFR) specific mutations have been known to improve survival of patients with non-small-cell lung carcinoma (NSCLC). However, whether there are any changes of EGFR mutations after targeted therapy and its clinical significance is unclear. This study was to identify the status of EGFR mutations after targeted therapy and predict the prognostic significance for NSCLC patients.

METHODS

A total of forty-five (45) NSCLC patients who received EGFR-TKI therapy were enrolled. We identified the changes of EGFR mutations in plasma ctDNA by Amplification Refractory Mutation System (ARMS) PCR technology.

RESULTS

In the 45 cases of NSCLC with EGFR mutations, the EGFR mutation status changed in 26 cases, in which, 12 cases (26.7%) from positive to negative, and 14 cases (31.1%) from T790M mutation negative to positive after TKI targeted therapy. The T790M occurance group had a shorter Progression -Free-Survival (PFS) than the groups of EGFR mutation undetected and EGFR mutation turned out to have no change after EGFR-TKI therapy (p < 0.05).

CONCLUSIONS

According to this study, it's necessary to closely monitor EGFR mutations during follow-up to predict the prognosis of NSCLC patients who are to receive the TKI targeted therapy.

ROR1 is a novel prognostic biomarker in patients with lung adenocarcinoma

Currently, there is no reliable biomarker to clinically predict the prognosis of lung adenocarcinoma (ADC). The receptor-tyrosine-kinase like orphan receptor 1 (ROR1) is reported to be overexpressed and associated with poor prognosis in several tumors. This study aimed to examine the expression of ROR1 and evaluate its prognostic significance in human lung ADC patients. In this present study, Western blot analysis and immunohistochemistry were performed to characterize expression of ROR1 protein in lung ADC patients. The results revealed that ROR1 protein expression was significantly higher in lung ADC tissues than that in their adjacent non-tumor tissues. Patients at advanced stages and those with positive lymph node metastasis expressed higher level of ROR1 (P < 0.001). Moreover, Chi-square test showed that ROR1 expression was correlated to gender (P = 0.028), the 7^th edition of the American Joint Committee on Cancer tumor-node-metastasis (AJCC TNM) staging system and lymph node metastasis (P < 0.001). Kaplan-Meier survival analysis indicated an association of high ROR1 expression with worse overall survival (OS) in lung ADC patients (P < 0.001). Multivariate COX regression analysis further confirmed that ROR1 is an independent prognostic predictor (P < 0.001, HR = 4.114, 95% CI: 2.513–6.375) for OS. Therefore, ROR1 expression significantly correlates with malignant attributes of lung ADC and it may serve as a novel prognostic marker in lung ADC patients.

The Evolution of Oncology Companion Diagnostics from Signal Transduction to Immuno-Oncology

Sixteen oncology drugs have been approved with a companion diagnostic (CDx) test by the FDA. These represent only 9.6% of the 167 oncology drug approvals since 1998, the year the first CDx test for Herceptin was approved. The great majority of CDx tests are for drugs that inhibit signal transduction pathways by either inhibiting the intracellular kinase activity with a small molecule or preventing ligand-induced receptor activation with a monoclonal antibody. In most of these cases, prospective patient selection for the biomarker-positive subpopulation was initiated in or before Phase II. The development of CDx tests for emerging immunotherapies will be more complicated because they are not dependent on driver mutations in the drug target, the mechanism of action is often pleiotropic, and will require both protein and cell-based assays to evaluate the interaction of the tumor with the immune system. Consequently, we will need to develop new biomarker strategies for the development of immunotherapies and to determine whether the optimum strategy is to release a prior checkpoint blockade in patients with a suppressed immune response, or to prime a new immune response to the tumor.

Tyrosine dephosphorylation enhances the therapeutic target activity of epidermal growth factor receptor (EGFR) by disrupting its interaction with estrogen receptor (ER)

Protein-protein interactions can increase or decrease its therapeutic target activity and the determining factors involved, however, are largely unknown. Here, we report that tyrosine-dephosphorylation of epidermal growth factor receptor (EGFR) increases its therapeutic target activity by disrupting its interaction with estrogen receptor (ER). Protein tyrosine phosphatase H1 (PTPH1) dephosphorylates the tyrosine kinase EGFR, disrupts its interaction with the nuclear receptor ER, and increases breast cancer sensitivity to small molecule tyrosine kinase inhibitors (TKIs). These effects require PTPH1 catalytic activity and its interaction with EGFR, suggesting that the phosphatase may increase the sensitivity by dephosphorylating EGFR leading to its dissociation with ER. Consistent with this notion, a nuclear-localization defective ER has a higher EGFR-binding activity and confers the resistance to TKI-induced growth inhibition. Additional analysis show that PTPH1 stabilizes EGFR, stimulates the membranous EGFR accumulation, and enhances the growth-inhibitory activity of a combination therapy of TKIs with an anti-estrogen. Since EGFR and ER both are substrates for PTPH1 in vitro and in intact cells, these results indicate that an inhibitory EGFR-ER protein complex can be switched off through a competitive enzyme-substrate binding. Our results would have important implications for the treatment of breast cancer with targeted therapeutics.

The epidermal growth factor receptor (EGFR / HER-1) gatekeeper mutation T790M is present in European patients with early breast cancer

The epidermal growth factor receptor (EGFR) is one of the major oncogenes identified in a variety of human malignancies including breast cancer (BC). EGFR-mutations have been studied in lung cancer for some years and are established as important markers in guiding therapy with tyrosine kinase inhibitors (TKIs). In contrast, EGFR-mutations have been reported to be rare if not absent in human BC, although recent evidence has suggested a significant worldwide variation in somatic EGFR-mutations. Therefore, we investigated the presence of EGFR-mutations in 131 norwegian patients diagnosed with early breast cancer using real-time PCR methods. In the present study we identified three patients with an EGFR-T790M-mutation. The PCR-findings were confirmed by direct Sanger sequencing. Two patients had triple-negative BC (TNBC) while the third was classified as luminal-A subtype. The difference in incidence of T790M mutations comparing the TNBC subgroup with the other BC subgroups was statistical significant (P = 0.023). No other EGFR mutations were identified in the entire cohort. Interestingly, none of the patients had received any previous cancer treatment. To our best knowledge, the EGFR-T790M-TKI-resistance mutation has not been previously detected in breast cancer patients. Our findings contrast with the observations made in lung cancer patients where the EGFR-T790M-mutation is classified as a typical „second mutation”causing resistance to TKI-therapy during ongoing anticancer therapy. In conclusion, we have demonstrated for the first time that the EGFR-T790M-mutation occurs in primary human breast cancer patients. In the present study the EGFR-T790M mutation was not accompanied by any simultaneous EGFR-activating mutation.

Valproic acid, an inhibitor of class I histone deacetylases, reverses acquired Erlotinib-resistance of lung adenocarcinoma cells: a Connectivity Mapping analysis and an experimental study

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have been used as a powerful targeting therapeutic agent for treatment of lung adenocarcinoma for years. Nevertheless, the efficacy of TKI was hampered by the appearance of acquired TKI-resistance. In the present study, we aimed to search, predict, and screen the agents that can overcome the acquired TKI-resistance of lung adenocarcinoma by using the expression profiles of differentially expressed genes (DEGs) and Connectivity map (CMAP). The profiles of DEGs were obtained by searching GEO microarray database, and then, they were submitted to CMAP for analysis in order to predict and screen the agent that might reverse the TKI-resistance of lung cancer cells. Next, the effects of the selected agent on TKI-resistant cancer cells were tested and the possible signaling pathways were also evaluated. As a result, valproic acid (VPA) was selected. Then, we used a low-concentration of VPA that has little effect on the cell growth for analysis. Interestingly, the results showed that treatment with a combination of VPA and Erlotinib significantly led to a decrease in cell viability and an increase in cell apoptosis for TKI-resistant HCC827-ER cells, relative to those treated with VPA or Erlotinib alone. Further experiments confirmed that inhibition of MAPK and AKT might be involved in this process. Analyzing the DEGs through the CMAP is a good strategy for exploitation of anti-tumor agents. VPA might markedly increase the sensitivity of TKI-resistant lung adenocarcinoma cells to Erlotinib, thus reversing the acquired TKI-resistance of cancer cells and raising VPA as a potential agent for TKI-resistant lung cancer therapy.

Silencing of Receptor Tyrosine Kinase ROR1 Inhibits Tumor-Cell Proliferation via PI3K/AKT/mTOR Signaling Pathway in Lung Adenocarcinoma

Receptor tyrosine kinase ROR1, an embryonic protein involved in organogenesis, is expressed in certain hematological malignancies and solid tumors, but is generally absent in adult tissues. This makes the protein an ideal drug target for cancer therapy. In order to assess the suitability of ROR1 as a cell surface antigen for targeted therapy of lung adenocarcinoma, we carried out a comprehensive analysis of ROR1 protein expression in human lung adenocarcinoma tissues and cell lines. Our data show that ROR1 protein is selectively expressed on lung adenocarcinoma cells, but do not support the hypothesis that expression levels of ROR1 are associated with aggressive disease. However silencing of ROR1 via siRNA treatment significantly down-regulates the activity of the PI3K/AKT/mTOR signaling pathway. This is associated with significant apoptosis and anti-proliferation of tumor cells. We found ROR1 protein expressed in lung adenocarcinoma but almost absent in tumor-adjacent tissues of the patients. The finding of ROR1-mediated proliferation signals in both tyrosine kinase inhibitor (TKI)-sensitive and -resistant tumor cells provides encouragement to develop ROR1-directed targeted therapy in lung adenocarcinoma, especially those with TKI resistance.

The role of the small GTPase Rab31 in cancer

Members of the small GTPase family Rab are emerging as potentially important factors in cancer development and progression. A good number of Rabs have been implicated or associated with various human cancers, and much recent excitement has been associated with the roles of the Rab11 subfamily member Rab25 and its effector, the Rab coupling protein (RCP), in tumourigenesis and metastasis. In this review, we focus on a Rab5 subfamily member, Rab31, and its implicated role in cancer. Well recognized as a breast cancer marker with good prognostic value, recent findings have provided some insights as to the mechanism underlying Rab31's influence on oncogenesis. Levels of Oestrogen Receptor α (ERα)- responsive Rab31 could be elevated through stabilization of its transcript by the RNA binding protein HuR, or though activation by the oncoprotein mucin1-C (MUC1-C), which forms a transcriptional complex with ERα. Elevated Rab31 stabilizes MUC1-C levels in an auto-inductive loop that could lead to aberrant signalling and gene expression associated with cancer progression. Rab31 and its guanine nucleotide exchange factor GAPex-5 have, however, also been shown to enhance early endosome-late endosome transport and degradation of the epidermal growth factor receptor (EGFR). The multifaceted action and influences of Rab31 in cancer is discussed in the light of its new interacting partners and pathways.

Lentiviral vector-mediated RBM5 overexpression downregulates EGFR expression in human non-small cell lung cancer cells

Background

RNA binding motif 5 (RBM5) is a tumor suppressor gene that modulates apoptosis through the regulation of alternative splicing of apoptosis-related genes. Our previous studies suggested that RBM5 expression was negatively correlated with the expression of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) tissues. This study was aimed at determining whether RBM5 is able to regulate EGFR expression.

Methods

Both in vitro and in vivo studies were carried out to determine the effect of RBM5 on the expression of EGFR. Lentiviral vector-mediated RBM5 overexpression was employed in lung adenocarcinoma cell line A549. A549 xenograft mice were treated with recombinant RBM5 plasmid carried by attenuated Salmonella typhi Ty21a. Real-time quantitative polymerase chain reaction and Western blot were carried out to detect RBM5 and EGFR expression.

Results

Both in vivo and in vitro studies indicated that the expression of EGFR mRNA and protein was decreased significantly in the RBM5 overexpression group compared to control groups as shown by real-time PCR and Western blot analysis. We identified that RBM5 overexpression inhibited EGFR expression both in A549 cells and in A549 xenograft mice model.

Conclusions

Our study demonstrated that EGFR expression is regulated by RBM5 in lung adenocarcinomas cells either in a direct or indirect way, which might be meaningful with regards to target therapy in lung cancer.

A phase I, dose-escalation trial of continuous- and pulsed-dose afatinib combined with pemetrexed in patients with advanced solid tumors

INTRODUCTION

Afatinib, an irreversible ErbB family blocker, demonstrated synergistic inhibition of epidermal growth factor receptor-mutant cell growth with pemetrexed. This phase I study investigated the maximum tolerated dose (MTD), safety, pharmacokinetics, and antitumor activity of afatinib plus pemetrexed in patients with advanced solid tumors.

METHODS

In a 3 + 3 dose-escalation design, patients were given intravenous pemetrexed (500 mg/m(2)) on day 1 of a 21-day cycle (maximum 6 cycles), combined with continuous daily oral afatinib (schedule A [SA]; starting dose 30 mg, escalation to 50 mg) or pulsed-dose daily oral afatinib (schedule B [SB]; starting dose 50 mg, escalation to 70 mg) on days 1-6 of each 21-day cycle. Primary endpoint was determination of MTD based on dose-limiting toxicities (DLTs) in cycle 1.

RESULTS

Fifty-three patients were treated (SA: n = 23; SB: n = 30). Eight patients had DLTs in SA, 11 patients in SB; diarrhea and fatigue were the most common. MTD of afatinib was 30 mg in SA and 50 mg in SB. Six patients in SA and eight in SB completed 6 treatment cycles. One patient in each schedule had confirmed objective response; 18/53 patients had disease control (SA: n = 7; SB: n = 11). Most frequent drug-related adverse events were diarrhea, rash, fatigue, and stomatitis. No relevant pharmacokinetic interactions were observed.

CONCLUSIONS

Continuous- or pulsed-dose afatinib combined with pemetrexed exhibited a manageable safety profile. Pulsed dosing conferred no apparent safety or dose advantage. Continuous-dose afatinib 30 mg/day with pemetrexed is recommended for phase II studies.

Oncogenic drivers, targeted therapies, and acquired resistance in non-small-cell lung cancer

In the past decade, a shift toward targeted therapies in non-small-cell lung cancer following molecular profiling has dramatically changed the way advanced adenocarcinoma is treated. However, tumor cells inevitably acquire resistance to such therapies, circumventing any sustained clinical benefit. As the genomic classification of lung cancer continues to evolve and as the mechanisms of acquired resistance to targeted therapies become elucidated and more improved target-specific drugs come into sight, the future will see more promising results from the clinic through the development of new therapeutic strategies to overcome, or prevent the development of, resistance for lung cancer patients.

Levels of active tyrosine kinase receptor determine the tumor response to Zalypsis

Background

Zalypsis® is a marine compound in phase II clinical trials for multiple myeloma, cervical and endometrial cancer, and Ewing’s sarcoma. However, the determinants of the response to Zalypsis are not well known. The identification of biomarkers for Zalypsis activity would also contribute to broaden the spectrum of tumors by selecting those patients more likely to respond to this therapy.

Methods

Using in vitro drug sensitivity data coupled with a set of molecular data from a panel of sarcoma cell lines, we developed molecular signatures that predict sensitivity to Zalypsis. We verified these results in culture and in vivo xenograft studies.

Results

Zalypsis resistance was dependent on the expression levels of PDGFRα or constitutive phosphorylation of c-Kit, indicating that the activation of tyrosine kinase receptors (TKRs) may determine resistance to Zalypsis. To validate our observation, we measured the levels of total and active (phosphorylated) forms of the RTKs PDGFRα/β, c-Kit, and EGFR in a new panel of diverse solid tumor cell lines and found that the IC50 to the drug correlated with RTK activation in this new panel. We further tested our predictions about Zalypsis determinants for response in vivo in xenograft models. All cells lines expressing low levels of RTK signaling were sensitive to Zalypsis in vivo, whereas all cell lines except two with high levels of RTK signaling were resistant to the drug.

Conclusions

RTK activation might provide important signals to overcome the cytotoxicity of Zalypsis and should be taken into consideration in current and future clinical trials.