Impact of the mucosal milieu on antibody responses to allergens.

Respiratory and digestive mucosal surfaces are continually exposed to common environmental antigens, which include potential allergens. Although innocuous in healthy individuals, allergens cause allergy in predisposed subjects and do so by triggering a pathologic TH2 cell response that induces IgE class switching and somatic hypermutation in allergen-specific B cells. The ensuing affinity maturation and plasma cell differentiation lead to the abnormal release of high-affinity IgE that binds to powerful FcεRI receptors on basophils and mast cells. When cross-linked by allergen, FcεRI-bound IgE instigates the release of prestored and de novo-induced proinflammatory mediators. Aside from causing type I hypersensitivity reactions underlying allergy, IgE affords protection against nematodes or venoms from insects and snakes, which raises questions as to the fundamental differences between protective and pathogenic IgE responses. In this review, we discuss the impact of the mucosal environment, including the epithelial and mucus barriers, on the induction of protective IgE responses against environmental antigens. We further discuss how perturbations of these barriers may contribute to the induction of pathogenic IgE production.

U937 variant cells as a model of apoptosis without cell disintegration.

The variant cell line U937V was originally identified by a higher sensitivity to the cytocidal action of tumor necrosis factor alpha (TNFα) than that of its reference cell line, U937. We noticed that a typical morphological feature of dying U937V cells was the lack of cellular disintegration, which contrasts to the formation of apoptotic bodies seen with dying U937 cells. We found that both TNFα, which induces the extrinsic apoptotic pathway, and etoposide (VP-16), which induces the intrinsic apoptotic pathway, stimulated U937V cell death without cell disintegration. In spite of the distinct morphological differences between the U937 and U937V cells, the basic molecular events of apoptosis, such as internucleosomal DNA degradation, phosphatidylserine exposure on the outer leaflet of the plasma membrane, caspase activation and cytochrome c release, were evident in both cell types when stimulated with both types of apoptosis inducer. In the U937V cells, we noted an accelerated release of cytochrome c, an accelerated decrease in mitochondrial membrane potential, and a more pronounced generation of reactive oxygen species compared to the reference cells. We propose that the U937 and U937V cell lines could serve as excellent comparison models for studies on the mechanisms regulating the processes of cellular disintegration during apoptosis, such as blebbing (zeiosis) and apoptotic body formation.

Digital multiplexed analysis of circular RNAs in FFPE and fresh non-small cell lung cancer specimens.

Although many studies highlight the implication of circular RNAs (circRNAs) in carcinogenesis and tumor progression, their potential as cancer biomarkers has not yet been fully explored in the clinic due to the limitations of current quantification methods. Here, we report the use of the nCounter platform as a valid technology for the analysis of circRNA expression patterns in non-small cell lung cancer (NSCLC) specimens. Under this context, our custom-made circRNA panel was able to detect circRNA expression both in NSCLC cells and formalin-fixed paraffin-embedded (FFPE) tissues. CircFUT8 was overexpressed in NSCLC, contrasting with circEPB41L2, circBNC2, and circSOX13 downregulation even at the early stages of the disease. Machine learning (ML) approaches from different paradigms allowed discrimination of NSCLC from nontumor controls (NTCs) with an 8-circRNA signature. An additional 4-circRNA signature was able to classify early-stage NSCLC samples from NTC, reaching a maximum area under the ROC curve (AUC) of 0.981. Our results not only present two circRNA signatures with diagnosis potential but also introduce nCounter processing following ML as a feasible protocol for the study and development of circRNA signatures for NSCLC.

Multiplex Analysis of CircRNAs from Plasma Extracellular Vesicle-Enriched Samples for the Detection of Early-Stage Non-Small Cell Lung Cancer.

BACKGROUND: The analysis of liquid biopsies brings new opportunities in the precision oncology field. Under this context, extracellular vesicle circular RNAs (EV-circRNAs) have gained interest as biomarkers for lung cancer (LC) detection. However, standardized and robust protocols need to be developed to boost their potential in the clinical setting. Although nCounter has been used for the analysis of other liquid biopsy substrates and biomarkers, it has never been employed for EV-circRNA analysis of LC patients. METHODS: EVs were isolated from early-stage LC patients (n = 36) and controls (n = 30). Different volumes of plasma, together with different number of pre-amplification cycles, were tested to reach the best nCounter outcome. Differential expression analysis of circRNAs was performed, along with the testing of different machine learning (ML) methods for the development of a prognostic signature for LC. RESULTS: A combination of 500 µL of plasma input with 10 cycles of pre-amplification was selected for the rest of the study. Eight circRNAs were found upregulated in LC. Further ML analysis selected a 10-circRNA signature able to discriminate LC from controls with AUC ROC of 0.86. CONCLUSIONS: This study validates the use of the nCounter platform for multiplexed EV-circRNA expression studies in LC patient samples, allowing the development of prognostic signatures.

Mutated circulating tumor DNA as a liquid biopsy in lung cancer detection and treatment.

Over the past decade, substantial developments have been made in the detection of circulating tumor DNA (ctDNA)-cell-free DNA (cfDNA) fragments released into the circulation from tumor cells and displaying the genetic alterations of those cells. As such, ctDNA detected in liquid biopsies serves as a powerful tool for cancer patient stratification, therapy guidance, detection of resistance, and relapse monitoring. In this Review, we describe lung cancer diagnosis and monitoring strategies using ctDNA detection technologies and compile recent evidence regarding lung cancer-related mutation detection in liquid biopsy. We focus not only on epidermal growth factor receptor (EGFR) alterations, but also on significant co-mutations that shed more light on novel ctDNA-based liquid biopsy applications. Finally, we discuss future perspectives of early-cancer detection and clonal hematopoiesis filtering strategies, with possible inclusion of microbiome-driven liquid biopsy.

Biological therapies in lung cancer treatment: using our immune system as an ally to defeat the malignancy.

INTRODUCTION: Biological therapies, with immunotherapy leading the field, have arisen as one of the quickest expanding areas of research for cancer treatment in the last few years. The clear benefits for patients are undeniable, satisfying the long-awaited necessity of a target-specific therapy. However, its full potential remains still unexploited due to a lack of response in a majority of patients and pending reliable biomarkers. AREAS COVERED: This review provides a summarizing view of the current biological therapies for lung cancer, focusing on immunotherapy - including immune checkpoint inhibitors, adoptive cell therapy and vaccines available in clinical/pre-clinical settings or currently in development. A thorough analysis of the technical and functional differences among all therapies is provided, along with a critical discussion of prospective treatments and potential biomarkers. EXPERT OPINION: The use of immunotherapy in the treatment of cancer has provided clear benefits for patients. Still, exploitation of the full potential of immune checkpoint inhibitors alone or in combination, or adoptive cell therapies is hampered by, amongst other reasons, the lack of reliable biomarkers and possible adverse immune effects. We postulate that the development of liquid biopsy-based diagnostics will help to overcome these limitations in the near future.

ALDH1-positive intratumoral stromal cells indicate differentiated epithelial-like phenotype and good prognosis in prostate cancer.

Aldehyde dehydrogenase 1 (ALDH1) characterizes tumor-initiating cells in solid tumors; however, little is known about its expression in intratumoral stromal cells. Herein, we aimed to dissect its potential dual relevance in prostate cancer (PCa). ALDH1 expression was evaluated immunohistochemically in tumor and stromal cells in primary PCa and metastases. It was correlated to clinico-pathologic parameters, patients' outcome, and selected proteins (CK5/6, CK14, CK8/18, CK19, EpCAM, Ki-67, E-cadherin, N-cadherin, and vimentin). ALDH1 protein was detected in tumor and stromal cells in 16% and 67% of 348 primary PCa, respectively. Tumor cell ALDH1 expression was associated with advanced T stage (P = 0.009), higher Gleason score (P = 0.016), shorter time to biochemical recurrence (TBR P = 0.010) and CK14 expression (P = 0.023). Stromal cell ALDH1 expression correlated to lower T stage (P = 0.008) and Gleason score (P = 0.016), N0 stage (P = 0.017), and longer TBR (P = 0.017). It occurred to be an independent predictor of good prognosis in the subgroup of d'Amico high-risk patients (multivariate analysis, P = 0.050). ALDH1-positive stromal cells were found in tumors characterized frequently by CK8/18 (P = 0.033) or EpCAM expression (P < 0.001) and rarely by epithelial-mesenchymal transition defined as CK8/18(-)vimentin(+) phenotype (P = 0.003). ALDH1-positive tumor and stromal cells were detected in 33% and 41% of hormone naive lymph node metastases (n = 63), 52% and 24% of castration resistant bone metastases, as well as 89% and 28% of castration resistant visceral metastases (n = 21), respectively. We have determined that contrary to tumor cell ALDH1, the presence of stromal ALDH1 is associated with epithelial phenotype of primary PCa, improved clinical outcome, and is less frequent in PCa metastases.

Osimertinib and pterostilbene in EGFR-mutation-positive non-small cell lung cancer (NSCLC).

Monotherapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) still leads to incomplete responses in most EGFR-mutation positive non-small cell lung cancer (NSCLC) patients, often due to acquired resistance through activation of parallel compensatory pathways. We have previously shown that co-targeting EGFR, signal transducer and activator of transcription 3 (STAT3), and Src-yes-associated protein 1 (YAP1) was highly synergistic in vitro and in vivo. In the present study, we treated EGFR-mutation positive cell lines with the combination of osimertinib plus a natural compound, pterostilbene, which has been reported to abrogate Src and STAT3 activation. Methods: Cell viability assays and immunoblotting were performed to reveal the mechanisms of action of pterostilbene, osimertinib and pterostilbene plus osimertinib in five EGFR-mutation positive NSCLC and one triple negative breast cancer (TNBC) cell lines. Results: Osimertinib plus pterostilbene yielded synergistic effects in all EGFR-mutation positive NSCLC cell lines investigated. Surprisingly, pterostilbene alone did not inhibit, nor downregulate Src phosphorylation in the EGFR-mutation positive NSCLC cell lines or the TNBC cell line, MDA-MB-231. However, the double combination of osimertinib plus pterostilbene reversed the osimertinib-induced STAT3, YAP1, and CUB domain-containing protein-1 (CDCP1) phosphorylation and slightly suppressed Src phosphorylation in PC9 and H1975 cells. Conclusion: The results of this study indicate that pterostilbene may be used to abrogate the activated resistance pathways of single osimertinib treatment in EGFR-mutation positive NSCLC. Future studies should focus on in vivo translation and confirmation of these results.

Characterising acquired resistance to erlotinib in non-small cell lung cancer patients.

Introduction: The therapy of patients with lung adenocarcinoma has significantly changed after the discovery of epidermal growth factor receptor (EGFR) mutations. EGFR mutations occur in 10-15% of Caucasian lung cancer patients and are associated with favorable outcome to orally administered EGFR tyrosine kinase inhibitors (TKIs), like erlotinib. However, as soon as the tumor cells are under the pressure of the specific inhibitor, compensatory signaling pathways are activated and resistance emerges. Areas covered: In this review we will focus on the mechanisms of resistance to the first-generation EGFR TKI, erlotinib, and will mainly summarize the findings throughout the last 10 years in the field of EGFR-mutant lung cancer. Expert opinion: Widespread research has been performed and several mechanisms of resistance to EGFR TKIs, especially first- and second-generation, have been identified. Still, no adequate combinatory therapies have received regulatory approval for the treatment of EGFR-mutant patients at the time of resistance. The third-generation EGFR TKI, osimertinib has been approved for patients whose tumor has become resistant through the secondary T790M resistant EGFR mutation. The identification of the mechanisms of resistance and the application of the adequate therapy to each patient is still an unmet need.

Osimertinib and dihydroartemisinin: a novel drug combination targeting head and neck squamous cell carcinoma.

BACKGROUND: Recurrent and metastatic head and neck squamous cell carcinoma (HNSCC) has a dismal prognosis with limited progression-free survival and overall survival, even when treated with different combinations of chemotherapy, targeted therapies and immunotherapy. We explored in vitro and in vivo the effect of the epidermal growth factor receptor (EGFR) inhibitor, osimertinib, alone and in combination with dihydroartemisinin (DHA) in HNSCC. METHODS: The combination of osimertinib with DHA was tested in the FaDu and CAL27 HNSCC cell lines. Tumor cell proliferation assays were conducted in cultured cells and mouse xenografts. Western blotting analysis of related signal pathways was performed to investigate the molecular mechanisms of the inhibitory effect of DHA and the combination. Other compounds, which inhibit signal transducer and activator of transcription 3 (STAT3), Src-family kinases (SFKs), sphingosine kinase 1 (SPHK1), or the receptor tyrosine kinase (RTK) AXL were also combined with osimertinib in vitro. RESULTS: Osimertinib exerted synergistic cytotoxicity toward FaDu and CAL27 HNSCC cells when combined with DHA. DHA reversed the osimertinib-induced STAT3 and Src phosphorylation. The double combination inhibited AXL expression. The anticancer potential of osimertinib plus DHA combination was validated in vivo on FaDu and CAL27 xenografts in mice without notable side effects. CONCLUSIONS: The results illustrate that the combinatory therapy of osimertinib and DHA, as a repurposing anticancer drug, could be a novel therapeutic strategy for recurrent and/or metastatic HNSCC patients. The findings strongly indicate that a clinical trial is warranted to confirm the benefit of the combination.

MiR-192 and miR-662 enhance chemoresistance and invasiveness of squamous cell lung carcinoma.

OBJECTIVES: Overexpression of miR-192, miR-192* and miR-662 was previously found to correlate with poor prognosis of early-stage squamous cell lung cancer (SCC) patients. In this study, we investigated the relevance of these miRNAs to cancer cell biology and chemoresistance. MATERIALS AND METHODS: MiRNA expression profile was analysed in 10 non-small cell lung cancer (NSCLC) cell lines using RT-qPCR. H520 and H1703 cells were transfected with miRNA inhibitors (anti-miR-192, -192* and -662) for functional studies. Chemoresistance to cisplatin and etoposide was evaluated using MTT colorimetric assay. H520 cells were subjected to 3D soft-agar colony formation assay and H1703 cells to wound healing assay. Whole transcriptome analysis was used to assess the effect of miR-192 and miR-662 inhibition on gene expression. RESULTS: SCC cell lines, H520 and H1703, differed in miRNA expression and phenotypic features. MiR-192 and miR-662 inhibition decreased clonogenicity and motility of SCC cells. MiR-192 and miR-662 inhibition sensitized SCC cells to etoposide but not to cisplatin. Whole transcriptome analysis revealed genes regulated by miR-192 and miR-662 in SCC, relevant to maintaining chemoresistance, invasiveness, epithelial-mesenchymal transition (EMT) and immune evasion. CONCLUSIONS: We showed for the first time that miR-192 and miR-662 have functional role in SCC cells. Our findings suggest that targeting these miRNAs may impact both chemoresistance and invasiveness of SCC, and add to the evidence linking these aspects of tumour biology. Overexpression of miR-192 and miR-662 might be useful as a marker of resistance to etoposide.