ELTD1-deletion reduces vascular abnormality and improves T-cell recruitment after PD-1 blockade in glioma

Combination of tumor antigen drainage and immune activation to promote a cancer-immunity cycle against glioblastoma

While conventional cancer modalities, such as chemotherapy and radiotherapy, act through direct killing of tumor cells, cancer immunotherapy elicits potent anti-tumor immune responses thereby eliminating tumors. Nevertheless, promising outcomes have not been reported in patients with glioblastoma (GBM) likely due to the immune privileged status of the central nervous system and immunosuppressive micro-environment within GBM. In the past years, several exciting findings, such as the re-discovery of meningeal lymphatic vessels (MLVs), three-dimensional anatomical reconstruction of MLV networks, and the demonstration of the promotion of GBM immunosurveillance by lymphatic drainage enhancement, have revealed an intricate communication between the nervous and immune systems, and brought hope for the development of new GBM treatment. Based on conceptual framework of the updated cancer-immunity (CI) cycle, here we focus on GBM antigen drainage and immune activation, the early events in driving the CI cycle. We also discuss the implications of these findings for developing new therapeutic approaches in tackling fatal GBM in the future.

Single-cell analysis reveals ADGRL4+ renal tubule cells as a highly aggressive cell type in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a highly heterogeneous cancer that poses great challenge to clinical treatment and prognostic prediction. Characterizing the cellular landscape of ccRCC in a single-cell dimension can help better understand the tumor heterogeneity and molecular mechanisms of ccRCC. This study analyzed single-cell profiles in ccRCC samples and para-tumor samples from Gene Expression Omnibus and identified a highly heterogeneous subcluster of renal tubule cells. Single-cell regulatory network inference and clustering analyses and cell communication analysis were performed to develop transcription factor-target gene regulatory networks and cell-cell interactions. Additionally, the distribution and prognostic risk of renal tubule cells from spatial transcriptome data (GSM6415706) and The Cancer Genome Atlas-Kidney Clear Cell Carcinoma data were analyzed. A total of 10 cell types were identified in ccRCC and para-tumor samples. The ccRCC renal tubule cells showed a high expression of the oncogene nicotinamide N-methyltransferase and a significantly high degree of tumor heterogeneity. We further identified 6 cell subclusters with specific expression of BEX2, PTHLH, SFRP2, KLRB1, ADGRL4, and HGF from the ccRCC renal tubule cells. ADGRL4+ renal tubule cells had highly metastatic and angiogenesis-inducing characteristics, with more ADGRL4+ renal tubule cells indicating a worse survival. ADGRL4+ renal tubule cells regulated the metastasis of other renal tubule cells through metastasis-related receptor-ligand communication. We also found that ADGRL4+ renal tubule cells clustered around the glomeruli but the rest of the renal tubule cell subclusters rarely localized in ccRCC tissues. ETS1 and ELK3 -dominant GRNs were remarkably activated in ADGRL4+ renal tubule cells, functionally, knockdown of ELK3 in A498 significantly disturbedaffected the cell migration and invasion. ADGRL4+ renal tubule cells, which were highly metastatic and invasive, might be an essential cell subcluster for ccRCC, and ADGRL4 could be used a novel therapeutic target.

Tanshinone IIA normalized hepatocellular carcinoma vessels and enhanced PD-1 inhibitor efficacy by inhibiting ELTD1

BACKGROUND

Hepatocellular carcinoma responds poorly to immune checkpoint inhibitors, such as PD-1 inhibitors, primarily due to the low infiltration capacity of TILs in the TME. Abnormal vasculature is an important factor which limiting the infiltration of TILs. According to recent research, targeting ELTD1 expression may improve TILs delivery to reverse immunosuppression and boost tumor responses to immunotherapy. Research has demonstrated that Tanshinone IIA (TSA) improves blood vessel normalization, but the precise mechanism is yet unknown.

PURPOSE

The purpose of this study is to investigate the molecular processes for TSA's pro-vascular normalization of HCC in vitro and in vivo.

METHODS

We established a mouse H22-luc in situ liver tumor model to evaluate the role of TSA vascular normalization and the immunosuppressive microenvironment. The role of ELTD1 in vascular and immune crosstalk was evaluated by bioinformatic analysis of the TCGA database. By creating a transwell co-culture cell model, the effects of TSA on enhancing tumor endothelial cell activities and ELTD1 intervention were evaluated.

RESULTS

We investigated the effect of Tanshinone IIA (TSA), a major component of Salvia miltiorrhiza Bge., on the normalization of vasculature in situ HCC models. Our results demonstrated that TSA elicited vascular normalization in a hepatocellular carcinoma model in situ. In addition, the combination of TSA with anti-PD-1 significantly inhibited tumor development due to increased infiltration of immune cells in the tumor. Mechanistically, we demonstrated that TSA improved the immunosuppressive microenvironment by inhibiting tumor growth by suppressing ELTD1 expression, inhibiting downstream JAK1 and JAK2, promoting the expression of ZO-1, occlaudin, Claudin 5, and Col IV, and promoting vascular integrity and perfusion in situ.

CONCLUSIONS

This study reveals a new mechanism between TSA and ELTD1 for vascular normalization, suggesting that therapeutic or pharmacological intervention with ELTD1 may enhance the efficacy of PD-1 inhibitors in HCC.

Limited Effects of Class II Transactivator-Based Immunotherapy in Murine and Human Glioblastoma

BACKGROUND

The major histocompatibility complex type II is downregulated in glioblastoma (GB) due to the silencing of the major transcriptional regulator class II transactivator (CIITA). We investigated the pro-immunogenic potential of CIITA overexpression in mouse and human GB.

METHODS

The intracerebral growth of wildtype GL261-WT cells was assessed following contralateral injection of GL261-CIITA cells or flank injections with GL261-WT or GL261-CIITA cells. Splenocytes obtained from mice implanted intracerebrally with GL261-WT, GL261-CIITA cells or phosphate buffered saline (PBS) were transferred to other mice and subsequently implanted intracerebrally with GL261-WT. Human GB cells and (syngeneic) GB-infiltrating immune cells were isolated from surgical samples and co-cultured with GB cells expressing CIITA or not, followed by RT-qPCR assessment of the expression of key immune regulators.

RESULTS

Intracerebral vaccination of GL261-CIITA significantly reduced the subsequent growth of GL261-WT cells implanted contralaterally. Vaccination with GL261-WT or -CIITA subcutaneously, however, equivalently retarded the intracerebral growth of GL261 cells. Adoptive cell transfer experiments showed a similar antitumor potential of lymphocytes harvested from mice implanted intracerebrally with GL261-WT or -CIITA. Human GB-infiltrating myeloid cells and lymphocytes were not activated when cultured with CIITA-expressing GB cells. Tumor-infiltrating NK cells remained mostly inactivated when in co-culture with GB cells, regardless of CIITA.

CONCLUSION

these results question the therapeutic potential of CIITA-mediated immunotherapy in glioblastoma.

A Trojan-Horse-Like Biomimetic Nano-NK to Elicit an Immunostimulatory Tumor Microenvironment for Enhanced GBM Chemo-Immunotherapy

Although the chemo- and immuno-therapies have obtained good responses for several solid tumors, including those with brain metastasis, their clinical efficacy in glioblastoma (GBM) is disappointing. The lack of safe and effective delivery systems across the blood-brain barrier (BBB) and the immunosuppressive tumor microenvironment (TME) are two main hurdles for GBM therapy. Herein, a Trojan-horse-like nanoparticle system is designed, which encapsulates biocompatible PLGA-coated temozolomide (TMZ) and IL-15 nanoparticles (NPs) with cRGD-decorated NK cell membrane (R-NKm@NP), to elicit the immunostimulatory TME for GBM chemo-immunotherapy. Taking advantage of the outer NK cell membrane cooperating with cRGD, the R-NKm@NPs effectively traversed across the BBB and targeted GBM. In addition, the R-NKm@NPs exhibited good antitumor ability and prolonged the median survival of GBM-bearing mice. Notably, after R-NKm@NPs treatment, the locally released TMZ and IL-15 synergistically stimulated the proliferation and activation of NK cells, leading to the maturation of dendritic cells and infiltration of CD8+ cytotoxic T cells, eliciting an immunostimulatory TME. Lastly, the R-NKm@NPs not only effectively prolonged the metabolic cycling time of the drugs in vivo, but also has no noticeable side effects. This study may offer valuable insights for developing biomimetic nanoparticles to potentiate GBM chemo- and immuno-therapies in the future.

[Latest Research Findings on the Role of Non-Tumor Cells in Glioma Microenvironment]

As the tumor cell-centered treatment strategies cannot curb the malignant progression of glioblastoma effectively, the therapeutic effect of glioblastoma is still not satisfactory. In addition to glioma cells, glioma microenvironment (GME) comprises massive numbers of non-tumor cells and soluble cytokines. The non-tumor cells include endothelial cells, pericytes, microglia/macrophages, mesenchymal cells, astrocytes, neurons, etc. These non-tumor cell components, together with glioma cells, form one organism which regulates the progression of glioma. Considerable progress has been been in research on GME, which will be conducive to the development of non-tumor cell targeted therapies and and improvements in the prognosis of glioma patients. Herein, we summarized the interaction of glioma cells with endothelial cells, pericytes, microglia/macrophages, astrocytes, neurons and mesenchymal cells, a topic that has been extensively researched, as well as the corresponding translational studies. We also discussed the potential challenges and opportunities of developing glioma treatments based on tumor microenvironment.

Perspectives on Vascular Regulation of Mechanisms Controlling Selective Immune Cell Function in the Tumor Immune Response

The vasculature plays a major role in regulating the tumor immune cell response although the underlying mechanisms explaining such effects remain poorly understood. This review discusses current knowledge on known vascular functions with a viewpoint on how they may yield distinct immune responses. The vasculature might directly influence selective immune cell infiltration into tumors by its cell surface expression of cell adhesion molecules, expression of cytokines, cell junction properties, focal adhesions, cytoskeleton and functional capacity. This will alter the tumor microenvironment and unleash a plethora of responses that will influence the tumor’s immune status. Despite our current knowledge of numerous mechanisms operating, the field is underexplored in that few functions providing a high degree of specificity have yet been provided in relation to the enormous divergence of responses apparent in human cancers. Further exploration of this field is much warranted.