Oncolytic vaccines increase the response to PD-L1 blockade in immunogenic and poorly immunogenic tumors.

Activation of immune checkpoint pathways and limited T- cell infiltration result in immunological escape of tumors. Although immune checkpoint inhibitors are currently approved for several types of cancers, the response rate is often limited by the lack of tumor specific T-cells within the malignant tissue. Therefore, new combinatorial strategies are needed to enhance the clinical benefit of immune checkpoint inhibitors. We have previously developed PeptiCRAd, an oncolytic vaccine platform capable of directing the immune response toward tumor epitopes. In this study, we evaluated whether the platform could be used to increase the response rate to checkpoint inhibitors in both highly immunogenic and poorly immunogenic tumors, such as melanoma and triple negative breast cancer (TNBC). We report here that anti-PD-L1 therapy in combination with PeptiCRAd significantly reduced the growth of melanomas and increased the response rate to checkpoint inhibition. In fact, we registered a higher rate of complete responses among mice treated with the combination. This approach promoted the presence of non-exhausted antigen-specific T-cells within the tumor in comparison to anti-PD-L1 monotherapy. Furthermore, we found that targeting both MHC-I and II restricted tumor epitopes was necessary to decrease the growth of the poorly immunogenic TNBC model 4T1 and that combination with PD-L1 blockade increased the number of responders to checkpoint inhibition. Finally, the described strategy was validated in a translational in vitro model using HLA matched human PBMCs and tumor cell lines. Consistent to our previous results, improved cytotoxicity was observed with combination of PeptiCRAd and anti-PD-L1. These results demonstrate that oncolytic virus based cancer vaccine can significantly improve the response rate to checkpoint blocking antibodies in the context of immunogenic and non-immunogenic tumors.

Endothelin-1 induces increased fibronectin expression in human bronchial epithelial cells.

Endothelin-1 may be involved in the pathogenesis of asthma by causing bronchial smooth muscle constriction and airway remodelling. Bronchial epithelial cells represent an important source of endothelin-1 in this disease, and increased release of epithelial cell-derived endothelin-1 may contribute to the genesis of subepithelial fibrosis by promoting fibroblast proliferation and collagen production. In this study, we demonstrate that endothelin-1 upregulates fibronectin gene expression and fibronectin release in bronchial epithelial cells via an ETA receptor. Fibronectin is an important component of the extracellular matrix which is deposited in excess in the subepithelial area of asthmatic bronchial mucosa, and it represents a potent chemotactic factor for fibroblasts. Thus, endothelin-1 may induce subepithelial fibrosis both directly and by the autocrine mechanism reported here.

Constitutive expression of endothelin in bronchial epithelial cells of patients with symptomatic and asymptomatic asthma and modulation by histamine and interleukin-1.

BACKGROUND: An upregulation of endothelin-1 expression occurs in bronchial epithelial cells of asthmatic patients. This peptide may mediate bronchoconstriction in asthma, but the mechanisms that modulate endothelin-I synthesis and release are unknown. OBJECTIVE: This study was done to compare the pattern of endothelin-1 expression in patients with symptomatic and asymptomatic asthma and evaluate the ability of inflammatory factors to upregulate endothelin-1 synthesis and release in the epithelial cells of subjects who are free of symptoms. METHODS: Two groups of 10 asthmatic patients were selected. One group had symptomatic asthma with airflow obstruction and moderately to severely increased airway responsiveness. The second group was free of symptoms: they did not show airflow obstruction, and airway responsiveness was borderline or slightly increased. Bronchial biopsy specimens were obtained by means of bronchoscopy and used for immunohistochemical evaluation, epithelial cell isolation, and stimulation experiments with interleukin-1 and histamine. RESULTS: Endothelin-1 immunoreactivity was detected in vivo in the bronchial epithelial cells of all the patients with symptoms and in only two subjects without current symptoms. Incubation of bronchial epithelial cells from patients with asymptomatic asthma with interleukin-1 or histamine, for 8 to 24 hours, resulted in increased expression of endothelin-1 messenger RNA and release of appreciable amounts of the peptide to the culture medium. Those effects were dose- and time-dependent. Histamine and interleukin-1 were effective at concentrations similar to those detected in the bronchoalveolar lavage of patients with symptomatic asthma. CONCLUSION: Endothelin-expression is upregulated in bronchial epithelial cells of asthmatic patients with symptoms and evidence of functional derangement as compared with patients without symptoms and airflow obstruction. Exposure of cells from patients with asymptomatic asthma to factors that are released during acute exacerbation of the disease induces endothelin synthesis and release.

Bronchoconstrictive responses to inhaled ultrasonically nebulized distilled water and airway inflammation in asthma.

Twenty-two asthmatic patients with a range of airway hyperresponsiveness to methacholine underwent a bronchial challenge with ultrasonically nebulized distilled water (UNDW). The presence of positive responses to this stimulus was related to the extent of airway inflammation, as assessed by histochemical and immunohistochemical evaluation of bronchial biopsy specimens. Twelve patients had airflow obstruction during distilled water inhalation and they showed more severe disease than subjects with no response, as demonstrated by the higher degree of nonspecific bronchial hyperresponsiveness (p < 0.01), higher variability of peak expiratory flow rates (p < 0.01), symptom scores (p < 0.01), and daily use of bronchodilators (p < 0.01). Those patients also had increased numbers of mast cells and eosinophils (p < 0.01) and increased percentage of bronchial epithelial cells expressing endothelin 1 immunoreactivity (p < 0.01). Thus, positive responses to inhaled UNDW reflect the bronchial hyperresponsiveness consistent with moderate to severe asthma and may be due to the release of mediators with bronchoconstrictive properties from inflammatory cells or activated resident cells or both.