Life science
Medical & healthcare, Drug development, Cancer treatment

Therapeutic implication for regulationof immune cells via tumor vessels
Surgical Center, Osaka University Hospital
Associate Professor Takehiro Noda

https://researchmap.jp/t-noda?lang=en

Life science

Department of Gastroenterological Surgery, Graduate School of Medicine
Associate Professor Shogo Kobayashi

https://researchmap.jp/30452436?lang=en

Professor Hidetoshi Eguchi			https://researchmap.jp/abcdabcdabcd?lang=en

Abstract
Tumor blood vessels in the tumor microenvironment play important roles insolid tumor progression. The characteristics and functions of tumor endothelialcells (TEC) in tumor blood vessels are different from those of normal endothelial
cells (NEC). Indeed, compared with NECs, TECs have different morphology, altered blood flow, enhanced permeability, and structural abnormalities. The tumor
microenvironment consist of cancer cells, endothelial cells, immune cells andfibroblasts and the interaction of these cells influences cancer progression.
In the present study, we investigated the influence of TECs on tumor growth
and the host immune response. We compared TECs to NECs for their effects
on CD8+ T-cell functions. We performed next-generation sequencing on TECs
and NECs to investigate potential treatment targets, and we identified glycoprotein nonmetastatic melanoma protein B (GPNMB) as a candidate target.
Finally, we investigated the effects of targeting GPNMB in TECs.

some cancers. This indicates that targeting the constituent cells of the cancer
microenvironment can be a treatment for cancer itself. The main drugs for cancer treatment have been shifted to immune checkpoint inhibitors. In the future,
it is expected that research on immune cells mediated by tumor endothelial
cells in the cancer microenvironment will progress in order to maximize the effects of immunotherapy.

▍ Background & Results
In the field of cancer research, many studies have been conducted using
human cancer cell lines and immunodeficient mice. On the other hand, to create a model that reproduces the cancer microenvironment including immune
cells, it is impossible to perform sufficient analysis using immunodeficient mice.
In this study, we used immunocompetent mice to analyze the immune functionin the cancer microenvironment and created a novel mice model that is reproductive of tumor microenvironment.
Tumor formation was promoted in the group with cancer cells (BNL-T)
and TEC (BNL-T+TEC) compared to the control administered with normal
vascular endothelial cells (NEC) (BNL-T+NEC). The tumor volume increased
approximately 1.5 times (Fig. 1A, B). In the tumor tissue, it was confirmedthat CD8-positive T cells (green) remained in the CD31-positive tumor bloodvessel lumen (red) in the BNL-T+TEC group (Fig. 1C). The IFN-γ productionof CD8-positive T cells was significantly decreased, and CD8-positive T cells
exhaustion was observed.
The next-generation sequencing of TEC and NEC identified 42 genes, andexpression analysis using GSEA revealed that IFN-γ response signals wereinvolved (Sup. Fig. 1A, B). GPNMB, which is a transmembrane protein, wasone of the IFN signal-related genes, and GPNMB expression was observed in
the cytoplasm of TECs. In vivo, GPNMB was expressed in TEC in vitro and invivo. (Sup. Fig. 1C, D).
The knockdown of GPNMB expression in TEC significantly decreased thetumor volume, and increased the number of tumor-infiltrating CD8-positive
T cells. The PD-1-positive Tim-3-positive CD8-positive T cells, which are exhausted T cell markers, were significantly decreased (Fig. 2A). Furthermore,
the ability of CD8-positive T cells to produce IFN-γ was significantly restored,
indicating an improvement in T cell exhaustion (Fig. 2B).

Figure 1

Figure 2▍ Significance of the research and Future perspective
For the comprehensive control of the tumor microenvironment, it is necessary to clarify the intercellular interactions of not only cancer cells but also constituent cells such as endothelial cells and immune cells. In recent years, there
has been remarkable progression in immunotherapy using immune checkpoint
inhibitors, and synergistic effects have also been shown by the combination
therapy with immune checkpoint inhibitors and anti-angiogenesis inhibitors inSupplementary Figure 1

P a t e n t
Tr e a t i s e

Sakano, Yoshihiro; Noda, Takehiro; Kobayashi, Shogo et al. Tumor endothelial cell-induced CD8+ T-cell exhaustion via GPNMB in hepatocellular
carcinoma. Cancer Sci. 2022, 113(5), 1625-1638. doi: 10.1111/cas.15331

URLK e y w o r d tumor endothelial cell, GPNMB, exhaustion, immune cell