A novel combination of chemotherapy and immunotherapy controls tumor growth in mice with a human immune system.

Mice reconstituted with a human immune system and bearing human tumors represent a promising model for developing novel cancer immunotherapies. Here, we used mass cytometry and multi-parametric flow cytometry to characterize human leukocytes infiltrating a human breast cancer tumor model in immunocompromised NOD.SCID.γc-null mice reconstituted with a human immune system and compared it to samples of breast cancer patients. We observed highly activated human CD4+ and CD8+ T cells in the tumor, as well as minor subsets of innate immune cells in both settings. We also report that ICOS+ CD4+ regulatory T cells (Treg) were enriched in the tumor relative to the periphery in humanized mice and patients, providing a target to affect Treg and tumor growth. Indeed, administration of a neutralizing mAb to human ICOS reduced Treg proportions and numbers and improved CD4 + T cell proliferation in humanized mice. Moreover, a combination of the anti-ICOS mAb with cyclophosphamide reduced tumor growth, and that was associated with an improved CD8 to Treg ratio. Depletion of human CD8+ T cells or of murine myeloid cells marginally affected the effect of the combination therapy. Altogether, our results indicate that a combination of anti-ICOS mAb and chemotherapy controls tumor growth in humanized mice, opening new perspectives for the treatment of breast cancer. One sentence summary: Targeting ICOS in combination with chemotherapy is a promising strategy to improve tumor immunity in humans.

Edelfosine: An Antitumor Drug Prototype.

BACKGROUND: Lung cancer is the most prevalent cancer and a high fatality disease. Despite of all available therapeutic approaches, drug resistance of chemotherapy agents for patients remain as an obstacle. New drugs integrating immunotherapeutic and conventional cytotoxic effects is a powerful strategy for the treatment of cancer to overcome this limitation. Antineoplastic phospholipids combine both of these activities by affecting lipid metabolism and signaling through lipid rafts. Therefore, they emerge as interesting scaffolds for designing new drugs. OBJECTIVE: We aimed to evaluate antineoplastic phospholipids as scaffolds for designing new drugs for lung cancer treatment. METHODS: The initial screening in A549 cells was performed by MTT assay. Others cytotoxic effects were evaluated in A549 cells by clonogenic assay, Matrigel 3D culture and flow cytometry analyses of cell cycle, apoptosis, mitochondrial membrane electronic potential and superoxide production. Immunological effects of ED were accessed on dendritic cells (DCs) and the expression of some markers were evaluated by flow cytometry. In vivo lung colonization analysis was performed after intravenously injection of A549 cells and daily treatment with ED. RESULTS: Herein, ED showed to be the most efficient compound concerning cytotoxic, thereby, ED was selected for following tests. ED showed a cytotoxic profile in both monolayer and 3D culture and also in vivo models using A549 cells. This profile is due to G0/G1 phase cellular arrest and apoptosis drove by mitochondrial membrane depolarization and superoxide overproduction. Moreover, ED modulated DCs toward an activated pattern by the increased expression of CD83 and a remarkable decreased expression of PD-L1/CD274 on DCs membrane. CONCLUSIONS: Thus, ED is an interesting antitumor drug prototype due to not only its direct cellular cytotoxicity but also given its immunological features.

Mechanisms of Resistance to Immune Checkpoint Antibodies.

Immunotherapy using checkpoint inhibitors has changed the way we treat several aggressive cancers such as melanoma, non-small cell lung and head & neck cancers, among others, with durable responses achieved in the metastatic setting. However, unfortunately, the vast majority of patients do not respond to checkpoint inhibition therapy and a minority of patients, who do respond to treatment, develop secondary resistance and experience relapse by mechanisms still inadequately understood. Emerging evidence shows that alterations in multiple signaling pathways are involved in primary and/or secondary resistance to checkpoint inhibition. In this review we discuss how selected cancer-cell autonomous cues may influence the outcome of cancer immunotherapy, particularly immune checkpoint inhibition.

Herpes Simplex Virus Glycoprotein D Targets a Specific Dendritic Cell Subset and Improves the Performance of Vaccines to Human Papillomavirus-Associated Tumors.

Cervical cancer is a major public health problem and one of the leading causes of cancer deaths in women. Virtually all cases of cervical cancer, as well as a growing share of anal and head/neck tumors, are associated with human papillomavirus (HPV) infection. Despite the effectiveness, the available prophylactic vaccines do not benefit women with cervical lesions or cancer. Therefore, the search of new immunotherapeutic approaches to treat HPV-induced tumors is still a priority. The present study characterizes a therapeutic antitumor vaccine based on the genetic fusion of the Herpes simplex virus-1 (HSV-1) glycoprotein D (gD) with the E7 oncoprotein from HPV-16 (gDE7). Two subcutaneous doses of gDE7, admixed with poly (I:C), conferred complete and long-lasting therapeutic antitumor protection on mice previously challenged with tumor cells expressing the HPV-16 oncoproteins. The vaccine induced multifunctional E7-specific CD8+ T cells with cytotoxic activity and effector memory phenotype (CD44+ CD62Llow). In addition, gDE7 admixed with poly (I:C) vaccination controlled the expansion of tumor-induced regulatory T cells and myeloid-derived suppressor cells. More importantly, gDE7 activated mouse CD11c+ CD8α+ and human BDCA3+ dendritic cells (DC), specialized in antigen cross-presentation to CD8+ T cells, under in vitro conditions. These results indicated that the activation of a specific DC population, mediated by gD, improved the antigen-specific immune responses and the therapeutic performance induced by antitumor vaccines. These results open perspectives for the clinical testing of gDE7-based vaccines under the concept of active immunization as a tool for the therapeutic control of cancer. Mol Cancer Ther; 16(9); 1922-33. ©2017 AACR.

Integrated innate mechanisms involved in airway allergic inflammation to the serine protease subtilisin.

Proteases are recognized environmental allergens, but little is known about the mechanisms responsible for sensing enzyme activity and initiating the development of allergic inflammation. Because usage of the serine protease subtilisin in the detergent industry resulted in an outbreak of occupational asthma in workers, we sought to develop an experimental model of allergic lung inflammation to subtilisin and to determine the immunological mechanisms involved in type 2 responses. By using a mouse model of allergic airway disease, we have defined in this study that s.c. or intranasal sensitization followed by airway challenge to subtilisin induces prototypic allergic lung inflammation, characterized by airway eosinophilia, type 2 cytokine release, mucus production, high levels of serum IgE, and airway reactivity. These allergic responses were dependent on subtilisin protease activity, protease-activated receptor-2, IL-33R ST2, and MyD88 signaling. Also, subtilisin stimulated the expression of the proallergic cytokines IL-1α, IL-33, thymic stromal lymphopoietin, and the growth factor amphiregulin in a human bronchial epithelial cell line. Notably, acute administration of subtilisin into the airways increased lung IL-5-producing type 2 innate lymphoid cells, which required protease-activated receptor-2 expression. Finally, subtilisin activity acted as a Th2 adjuvant to an unrelated airborne Ag-promoting allergic inflammation to inhaled OVA. Therefore, we established a murine model of occupational asthma to a serine protease and characterized the main molecular pathways involved in allergic sensitization to subtilisin that potentially contribute to initiate allergic airway disease.

Monocyte-derived dendritic cells reflect the immune functional status of a chromophobe renal cell carcinoma patient: could it be a general phenomenon?

PURPOSE: The chromophobe renal cell carcinoma (ChRCC), though associated with a hereditary cancer syndrome, has a good prognosis after tumor removal. The lack of recurrence could be related to the absence of immune system compromise in patients or to an effective functional recovery of immune functions after tumor removal. Thus, we evaluated monocyte-derived dendritic cells (Mo-DCs) in a 34-year-old male who had a ChRCC, before and after tumor removal. METHODS: CD14(+) monocytes from the patient's peripheral blood, 1 week before and 3 months after partial nephrectomy, were differentiated in vitro into immature and mature Mo-DCs. These were harvested, analyzed by flow cytometry and used as stimulators of allogeneic T cells. Supernatants from cultures were collected for cytokine analysis. RESULTS: Tumor removal was associated with decreased expression of PD-L1, but also, surprisingly, of CD205, HLA-DR, CD80 and CD86 by Mo-DCs. Also, Mo-DC's ability to stimulate T cell proliferation increased, along with IL-2Rα expression and IFN-γ production. Simultaneously, the patients' Mo-DCs ability to induce Foxp3(+) T cells decreased after surgery. One-year postoperative follow-up shows no tumor recurrence. CONCLUSION: The presence of a ChRCC affected Mo-DCs generated in vitro, which recovered their function after tumor removal. This indicates that the favorable outcome observed after ChRCC resection may be due to the restoration of immunocompetence. Furthermore, since functional alterations described for DCs within tumors may be also found in Mo-DCs, their accurate functional analysis-not restricted to the determination of their surface immunophenotype-may provide an indirect "window" to the tumor microenvironment.