Lenvatinib plus anti-PD-1 antibody combination treatment activates CD8+ T cells through reduction of tumor-associated macrophage and activation of the interferon pathway

Lenvatinib is a multiple receptor tyrosine kinase inhibitor targeting mainly vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) receptors. We investigated the immunomodulatory activities of lenvatinib in the tumor microenvironment and its mechanisms of enhanced antitumor activity when combined with a programmed cell death-1 (PD-1) blockade. Antitumor activity was examined in immunodeficient and immunocompetent mouse tumor models. Single-cell analysis, flow cytometric analysis, and immunohistochemistry were used to analyze immune cell populations and their activation. Gene co-expression network analysis and pathway analysis using RNA sequencing data were used to identify lenvatinib-driven combined activity with anti-PD-1 antibody (anti-PD-1). Lenvatinib showed potent antitumor activity in the immunocompetent tumor microenvironment compared with the immunodeficient tumor microenvironment. Antitumor activity of lenvatinib plus anti-PD-1 was greater than that of either single treatment. Flow cytometric analysis revealed that lenvatinib reduced tumor-associated macrophages (TAMs) and increased the percentage of activated CD8+ T cells secreting interferon (IFN)-γ+ and granzyme B (GzmB). Combination treatment further increased the percentage of T cells, especially CD8+ T cells, among CD45+ cells and increased IFN-γ+ and GzmB+ CD8+ T cells. Transcriptome analyses of tumors resected from treated mice showed that genes specifically regulated by the combination were significantly enriched for type-I IFN signaling. Pretreatment with lenvatinib followed by anti-PD-1 treatment induced significant antitumor activity compared with anti-PD-1 treatment alone. Our findings show that lenvatinib modulates cancer immunity in the tumor microenvironment by reducing TAMs and, when combined with PD-1 blockade, shows enhanced antitumor activity via the IFN signaling pathway. These findings provide a scientific rationale for combination therapy of lenvatinib with PD-1 blockade to improve cancer immunotherapy.

Abstract 5231: Undifferentiated cell maker rBC2LC-N lectin have high affinity to pancreatic cancer cells and residual cancer cells

The glycosylation in cancer cells remains still unclear despite the whole human genome understanding. Recent technical advances give us great awareness about the consequence of the glycosylation. The glycomes of cancer cell surfaces are often unique with aberrant glycans, including sialylation, fucosylation, O-glycan truncation, and N-and O-linked glycan branching. The sugar binding proteins named ‘lectins’ are helpful materials to recognize the glycan structure and characterization. Recent study suggested lectins are more widely accepted that involved in many biological phenomena inside mammalian or as chemical research tools. Despite years of effort to develop cancer therapies, there were no effective molecular targeting drugs for pancreatic adenocarcinoma (PDAC). One possible reason for this difficulties, PDAC cells are densely covered with glycans which may cause the recalcitrance to approach molecular targeting drugs. Our group developed a high-density lectin microarray using 96 kinds of lectins, in which a panel well-defined lectins is immobilized onto a slide, has been successfully used for high-throughput analysis of complex carbohydrates included in serum glycoproteins and whole cells. Using this approach, we demonstrated that a recombinant lectin probe, rBC2LC-N, specifically bound to undifferentiated pluripotent stem cells (ES/iPS cells), but not differentiated somatic cells; this has now been developed as a useful undifferentiation marker. In this study, we employed this lectin microarray to investigate the specific glycan that covered pancreatic cancer cells with stem cell features. Firstly, we selected a cell line which reflect clinical PDAC cells among 6 pancreatic cancer cell lines by morphological analysis and cancer stem cell marker expressions. As previously reported, we regarded Capan-1 cell line as a closest one which maintains both self-renewal and differentiation capacity. As a result, we successfully identified top 10 highlighted lectins which have significant specificity to pancreatic cancer cells. rBC2LC-N lectin was the most significant one (P value = 9.44E-17), followed by ADA (P= 7.05E-9), TJA2 (P= 1.4E-8), ACG (P= 1.11E-6). We reconfirmed the specific reactivity of these lectins to Capan-1 by FACS and lectin histochemistry. rBC2LC-N lectin reactivity in 70 clinical cases of PDAC revealed that all cases were confirmed to be positive. Furthermore, we investigated this rBC2LC-N lectin have a high affinity to residual cancer cells after gemcitabine treatment in patient derived xenograft models. These reactions well agreed with those of undifferentiated iPS/ES cells. These coincidental match of glycan expression between on iPS/ES cells and on pancreatic cancer cells may suggest a great benefit to understand the ambiguous stem cell recognition in cancer community and novel therapeutic strategy.

Citation Format: Osamu Shimomura, Tastsuya Oda, Hiroaki Tateno, Sho Tachino, Junji Matsui, Yuusuke Ozawa, Jun Hirabayashi, Nobuhiro Ohkohchi. Undifferentiated cell maker rBC2LC-N lectin have high affinity to pancreatic cancer cells and residual cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5231. doi:10.1158/1538-7445.AM2017-5231

Functional human Th17 clones with WT1-specific helper activity

Th17 plays important roles in the pathogenesis of various inflammatory and autoimmune diseases. Although the importance of Th17 in tumor immunity has also been suggested, precise roles of tumor-associated antigen-specific Th17 still remain poorly understood, especially in humans. We previously identified WT1332, a 16-mer helper epitope derived from tumor-associated antigen Wilms' tumor gene 1 (WT1) product, and WT1332-specific Th1 clones were established. In the present study, WT1-specific Th17 clones were established by the stimulation of peripheral blood mononuclear cells with the WT1332 helper peptide under human Th17-polarizing conditions. The WT1-specific Th17 clone exhibited the helper function for proliferation of conventional CD4(+) T cells in the antigenic stimulation-specific manner. This is the first report of establishment of functional Th17 clones with both antigen (WT1332) specificity and antigen-specific helper activity. Th17 clones established here and the method to establish antigen-specific Th17 clones should be a useful tool to further analyze the roles of human Th17 in tumor immunity.

Recognition of a natural WT1 epitope by a modified WT1 peptide-specific T-cell receptor

Wilms' tumor gene WT1 is highly expressed in leukemia and in various types of solid tumors and exerts an oncogenic function. Thus, WT1 protein is a most promising tumor-associated antigen. We have been successfully performing WT1 vaccination with a 9-mer modified WT1(235) peptide, which has one amino acid substitution (M→Y) at position 2 of 9-mer natural WT1(235) peptide (235-243 a.a.), for close to 700 HLA-A*24:02-positive patients with leukemia or solid tumors. Although vaccination of modified WT1(235) peptide induced natural WT1(235) peptide-recognizing cytotoxic T-lymphocytes (CTLs) and exerted cytotoxic activity towards leukemia and solid tumor cells that expressed the natural WT1(235) peptide (epitope) but not the vaccinated modified WT1(235) peptide (epitope), the molecular basis has remained unclear. In this study, we established a modified WT1(235) peptide-specific CTL clone, we isolated T-cell receptor (TCR) genes from it and transduced the TCR genes into CD8(+) T-cells. The TCR-transduced CD8(+) T-cells produced interferon-γ (IFNγ) and tumor necrosis factor-α (TNFα) in response to stimulation not only with the modified WT1(235) peptide but also with the natural WT1(235) peptide and lysed modified or natural WT1(235) peptide-pulsed target cells and endogenously WT1-expressing leukemia cells in a HLA-A*24:02-restriction manner. These results provided us, for the first time at molecular basis, with a proof-of-concept of modified WT1(235) peptide-based immunotherapy for natural WT1(235) peptide-expressing malignancies.