Vascularized 3D Human Skin Models in the Forefront of Dermatological Research

In vitro engineered skin models are emerging as an alternative platform to reduce and replace animal testing in dermatological research. Despite the progress made in recent years, considerable challenges still exist for the inclusion of diverse cell types within skin models. Blood vessels, in particular, are essential in maintaining tissue homeostasis and are one of many primary contributors to skin disease inception and progression. Substantial efforts in the past have allowed the successful fabrication of vascularized skin models that are currently utilized for disease modeling and drugs/cosmetics testing. This review first discusses the need for vascularization within tissue-engineered skin models, highlighting their role in skin grafting and disease pathophysiology. Second, the review spotlights the milestones and recent progress in the fabrication and utilization of vascularized skin models. Additionally, advances including the use of bioreactors, organ-on-a-chip devices, and organoid systems are briefly explored. Finally, the challenges and future outlook for vascularized skin models are addressed.

Checkpoint inhibitor/interleukin-based combination therapy of cancer

BACKGROUND

Immunotherapy using immune checkpoint inhibitors (ICIs) is the current focus in cancer immunotherapy. However, issues are raised in the area, as the recent studies showed that such therapeutic modality suffers from low durability and low or no efficacy for patients with some tumor types including cases with non-inflamed or cold cancers. Therefore, efforts have been made to solve the issue using immune combination therapy, such as the use of immunocytokines. The combination of ICI with interleukins (ILs) and IL-targeting agents is now under consideration in the area of therapy, and the primary results are promising.

PURPOSE

The focus of this review is to discuss the possibility of using ILs and IL-targeting drugs in combination with ICI in cancer immunotherapy and describing recent advances in the field using PEGylated ILs and fusion proteins. The key focus in this area is to reduce adverse events and to increase the efficacy and durability of such combination therapy.

Elevated serum interleukin-8 is associated with enhanced intratumor neutrophils and reduced clinical benefit of immune-checkpoint inhibitors

Serum interleukin-8 (IL-8) levels and tumor neutrophil infiltration are associated with worse prognosis in advanced cancers. Here, using a large-scale retrospective analysis, we show that elevated baseline serum IL-8 levels are associated with poor outcome in patients (n = 1,344) with advanced cancers treated with nivolumab and/or ipilimumab, everolimus or docetaxel in phase 3 clinical trials, revealing the importance of assessing serum IL-8 levels in identifying unfavorable tumor immunobiology and as an independent biomarker in patients receiving immune-checkpoint inhibitors.

Paradigms of vascularization in melanoma: Clinical significance and potential for therapeutic targeting

Melanoma is the most aggressive form of skin cancer. Malignant melanoma in particular has a poor prognosis and although treatment has improved, drug resistance continues to be a challenge. Angiogenesis, the formation of blood vessels from existing microvessels, precedes the progression of melanoma from a radial growth phase to a malignant phenotype. In addition, melanoma cells can form networks of vessel-like fluid conducting channels through vasculogenic mimicry (VM). Both angiogenesis and VM have been postulated to contribute to the development of resistance to treatment and to enable metastasis. Also, the metastatic spread of melanoma is highly dependent on lymphangiogenesis, the formation of lymphatic vessels from pre-existing vessels. Interestingly, the design and clinical testing of drugs that target VM and lymphangiogenesis lag behind that of angiogenesis inhibitors. Despite this, antiangiogenic drugs have not significantly improved the overall survival of melanoma patients, thus necessitating the targeting of alternative mechanisms. In this article, I review the roles of the three paradigms of tissue perfusion, namely, angiogenesis, VM and lymphangiogenesis, in promoting melanoma progression and metastasis. This article also explores the latest development and potential opportunities in the therapeutic targeting of these processes.

Melanoma immunotherapy: strategies to overcome pharmacological resistance

Introduction: Although checkpoint inhibitors have provided a breakthrough in how melanoma is treated, about half of patients still do not respond due to primary or acquired resistance. New strategies are, therefore, required to increase the number of patients benefiting from immunotherapy. This systematic review investigates novel combinations that may overcome immune resistance in patients with melanoma.Areas covered: We provide an overview of immune-related resistance mechanisms and the various therapeutic strategies that can be considered in attempting to overcome these barriers, including combined immunotherapy approaches and combinations with chemotherapy, radiotherapy, and targeted therapy.Expert opinion: The immune response is a dynamic process in which the tumor microenvironment and immune cells interact in a variety of ways. New treatment approaches aim to enrich the tumor microenvironment with immune-infiltrate and increase response to immune checkpoint inhibitors.

Simultaneous inhibition of CXCR1/2, TGF-β, and PD-L1 remodels the tumor and its microenvironment to drive antitumor immunity

BACKGROUND

Despite the success of immune checkpoint blockade therapy in the treatment of certain cancer types, only a small percentage of patients with solid malignancies achieve a durable response. Consequently, there is a need to develop novel approaches that could overcome mechanisms of tumor resistance to checkpoint inhibition. Emerging evidence has implicated the phenomenon of cancer plasticity or acquisition of mesenchymal features by epithelial tumor cells, as an immune resistance mechanism.

METHODS

Two soluble factors that mediate tumor cell plasticity in the context of epithelial-mesenchymal transition are interleukin 8 (IL-8) and transforming growth factor beta (TGF-β). In an attempt to overcome escape mechanisms mediated by these cytokines, here we investigated the use of a small molecule inhibitor of the IL-8 receptors CXCR1/2, and a bifunctional agent that simultaneously blocks programmed death ligand 1 (PD-L1) and traps soluble TGF-β.

RESULTS

We demonstrate that simultaneous inhibition of CXCR1/2, TGF-β, and PD-L1 signaling synergizes to reduce mesenchymal tumor features in murine models of breast and lung cancer, and to markedly increase expression of tumor epithelial E-cadherin while reducing infiltration with suppressive granulocytic myeloid-derived suppressor cells, significantly enhancing T-cell infiltration and activation in tumors, and leading to improved antitumor activity.

CONCLUSIONS

This study highlights the potential benefit of combined blockade of CXCR1/2 and TGF-β signaling for modulation of tumor plasticity and potential enhancement of tumor responses to PD-L1 blockade. The data provide rationale for the evaluation of this novel approach in the clinic.