CD36 expression in both immune and non-immune cells is known to be directly involved in cancer metastasis. Extracellular vesicles (EVs) secreted by malignant melanocytes play a vital role in developing tumor-promoting microenvironments, but it is unclear whether this is mediated through CD36. To understand the role of CD36 in melanoma, we first analyzed the SKCM dataset for clinical prognosis, evaluated the percentage of CD36 in lymphatic fluid-derived EVs (LEVs), and tested whether melanoma-derived EVs increase CD36 expression and induce M2-macrophage-like characteristics. Furthermore, we performed a multiplex immunofluorescence (MxIF) imaging analysis to evaluate the CD36 expression and its colocalization with various other cells in the lymph node (LN) of patients and control subjects. Our findings show that cutaneous melanoma patients have a worse clinical prognosis with high CD36 levels, and a higher percentage of CD36 in total LEVs were found at baseline in melanoma patients compared to control. We also found that monocytic and endothelial cells treated with melanoma EVs expressed more CD36 than untreated cells. Furthermore, melanoma-derived EVs can regulate immunosuppressive macrophage-like characteristics by upregulating CD36. The spatial imaging data show that cells in tumor-involved sentinel LNs exhibit a higher probability of CD36 expression than cells from control LNs, but this was not statistically significant. Conclusively, our findings demonstrated that CD36 plays a vital role in controlling the immunosuppressive microenvironment in the LN, which can promote the formation of a protumorigenic niche.

Background: The immune system and vascular endothelial growth factor (VEGF) may be influential in melanoma behavior. We performed a prospective, exploratory analysis in 10 stage III and 22 stage IV melanoma patients to observe factors influencing outcomes. Patients and methods: Patients accrued during 2010 and 2011 were treated according to standard protocols for disease stage. We analyzed selected biomarkers for predictive patterns of clinical response. Survival outcomes were calculated using Kaplan-Meier curves. Results: Baseline LDH was negatively correlated with length of survival and positively correlated to baseline VEGF in stage IV melanoma patients. We found a positive correlation between peripheral blood Treg concentrations and baseline VEGF in stage IV patients. No stage III patients died during the study period; median survival for stage IV patients was 48 months using a Kaplan-Meier survival curve, which illustrates the enrichment for exceptional stage IV survivors. Six stage IV patients remain disease free, including 4 of the 10 patients who received IL-2 +/− metastatectomy. Conclusions: Recent advances in immunotherapy have demonstrated durable therapeutic responses which may favorably impact survival. Examining T-cell characteristics of metastatic melanoma patients may gain further insight into underlying immunomodulation mechanisms to guide improved therapies.

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer. Common treatments following surgical resection include PD-1-targeting checkpoint inhibitors (pembrolizumab), as 20% of tumors are PD-L1 positive with or without systemic chemotherapy. Over the last several years, our laboratory has developed nano-immune conjugates (NIC) in which hydrophobic chemotherapy drugs like paclitaxel (PTX) and SN38, the active metabolite of irinotecan, are made water soluble by formulating them into albumin-based nanoparticles (nab) that are hydrophobically linked to various IgG1 monoclonal antibodies, creating an antigen-targetable nano-immune conjugate. To date, we have successfully tested PTX containing NICs linked to either VEGF- or CD20-targeted antibodies in two phase I clinical trials against multiple relapsed ovarian/uterine cancer or non-Hodgkin’s lymphoma, respectively. Herein, we describe a novel NIC created with either PTX or SN38 that is coated with anti-PD-L1-targeting antibodies for the treatment of a preclinical model of TNBC. In vitro testing suggests that the chemotherapy drug and antibody retain their toxicity and ligand binding capability in the context of the NIC. Furthermore, both the PTX and SN-38 NIC demonstrate superior anti-tumor efficacy relative to antibody and chemotherapy drugs alone in a PD-L1 + MDA-MB-231 human TNBC xenograft model, which could translate clinically to patients with TNBC.

Human cytomegalovirus (HCMV) induces long-lasting T cell immune responses that control but do not clear infection. Typical responses involve private T cell clones, expressing T cell antigen receptors (TCR) unique to a person, and also public T cell clones with identical TCRs active in different people. Here, we report the development of a pre-therapeutic immunostimulation modality against HCMV for human T cells, CD3 co-potentiation , and the clonal analysis of its effects in recall assays at single-cell resolution. CD3 co-potentiation of human T cells required identification of an intrinsically inert anti-CD3 Fab fragment that conditionally augmented signaling only when TCR was co-engaged with antigen. When applied in recall assays, CD3 co-potentiation enhanced the expansion of both public and private T cell clones responding to autologous HLA-A2(+) antigen-presenting cells and immunodominant NLV peptide from HCMV pp65 protein. Interestingly, public versus private TCR expression was associated with distinct clonal expansion signatures in response to recall stimulus. This implied that besides possible differences in their generation and selection in an immune response, public and private T cells may respond differently to pharmaco-immunomodulation. Furthermore, a third clonal expansion profile was observed upon CD3 co-potentiation of T cell clones from HLA-A2(-) donors and one HLA-A2(+) presumed-uninfected donor, where NLV was of low intrinsic potency. We conclude that human T cell copotentiation can increase the expansion of different classes of T cell clones responding to recall antigens of different strengths, and this may be exploitable for therapeutic development against chronic, persistent infections such as HCMV. Key Points: Human CD3 co-potentiation can enhance the clonal expansion of several classes of recall T cells responding to antigens. Enhanced expansion follows a unique pattern based on the immunodominance or weakness of antigen, and public or private TCR status.