Vascular reconstitution in the tumor for more effective tumor immunotherapy

[The effect of PHD inhibitor on tumor microenvironment and tumor immune response]

Since the approval of HIF-PH inhibitors, HIF-PH inhibitors have been used clinically, and many studies and clinical case reports have been reported in Japan. A lot of information has been accumulated on clinical usage. However, HIF-PH inhibitors require careful administration for cancer patients due to their action mechanism through upregulating hypoxia-inducible factors (HIFs) level. In cancer cells, HIFs affect tumor progression and contribute to chemo- and radio-resistance. On the other hand, upregulation of HIFs in immune cells is associated with inflammation and suppress tumor progression. However, these controversial effects are not clear in in vivo model. It is needed to reveal whether upregulating HIFs level is beneficial for cancer therapy or not. We have previously reported that HIF-PH inhibitor treatment in tumor bearing mice model led to reconstitute tumor blood vessel and inhibit tumor growth. In addition, these phenomena were caused by tumor infiltrated macrophages and they altered these phenotypes. In this review, we will describe our findings on the mechanism of tumor growth suppression by HIF-PH inhibitors. We also want to mention the risks and benefits of future HIF-PH inhibitors.

Manipulation of the crosstalk between tumor angiogenesis and immunosuppression in the tumor microenvironment: Insight into the combination therapy of anti-angiogenesis and immune checkpoint blockade

Immunotherapy has been recognized as an effective and important therapeutic modality for multiple types of cancer. Nevertheless, it has been increasing recognized that clinical benefits of immunotherapy are less than expected as evidenced by the fact that only a small population of cancer patients respond favorably to immunotherapy. The structurally and functionally abnormal tumor vasculature is a hallmark of most solid tumors and contributes to an immunosuppressive microenvironment, which poses a major challenge to immunotherapy. In turn, multiple immune cell subsets have profound consequences on promoting neovascularization. Vascular normalization, a promising anti-angiogenic strategy, can enhance vascular perfusion and promote the infiltration of immune effector cells into tumors via correcting aberrant tumor blood vessels, resulting in the potentiation of immunotherapy. More interestingly, immunotherapies are prone to boost the efficacy of various anti-angiogenic therapies and/or promote the morphological and functional alterations in tumor vasculature. Therefore, immune reprograming and vascular normalization appear to be reciprocally regulated. In this review, we mainly summarize how tumor vasculature propels an immunosuppressive phenotype and how innate and adaptive immune cells modulate angiogenesis during tumor progression. We further highlight recent advances of anti-angiogenic immunotherapies in preclinical and clinical settings to solidify the concept that targeting both tumor blood vessels and immune suppressive cells provides an efficacious approach for the treatment of cancer.

Elucidating the binding mechanism of LPA species and analogs in an LPA4 receptor homology model

Lysophosphatidic acid receptor 4 (LPA₄) has emerged as a potential therapeutic target for the treatment of a variety of diseases, including cancer and obesity-induced diabetes, but its structure remains to be revealed. In the present work, a homology model of LPA₄ was built for studying the binding mechanism of LPA species and analogs. Then five selected LPA species and analogs with structural variations in their phosphate groups, substitutions on the glycerol backbone, and fatty acyl chains were docked into the LPA₄ model, followed by molecular dynamics simulations and energy analyses. The computational results revealed that the aliphatic residues located at the vertical cleft of LPA₄ may form a hydrophobic environment for the fatty acyl moiety of LPA species and their analogs. Meanwhile, the positively charged residues in the central cavity of LPA₄ may form ionic interactions with the negatively charged hydrophilic head group of LPA species and their analogs. In addition, it was noted that a different binding mode of the hydrophilic head group in each species with the central cavity of the LPA₄ might lead to a special rearrangement of the fatty acyl moiety. Taken together, these results may facilitate understanding of the activation mechanism of LPA₄ and help design selective ligands to modulate its function for therapeutic purposes.

Oncolytic adenovirus promotes vascular normalization and nonclassical tertiary lymphoid structure formation through STING-mediated DC activation

Inducing a full antitumor immune response in the tumor microenvironment (TME) is essential for successful cancer immunotherapy. Here, we report that an oncolytic adenovirus carrying mIL-15 (Ad-IL15) can effectively induce antitumor immune response and inhibit tumor growth in a mouse model of cancer. We found that Ad-IL15 facilitated the activation and infiltration of immune cells, including dendritic cells (DCs), T cells and natural killer (NK) cells, in the TME. Unexpectedly, we observed that Ad-IL15 also induced vascular normalization and tertiary lymphoid structure formation in the TME. Moreover, we demonstrated these Ad-IL15-induced changes in the TME were depended on the Ad-IL15-induced activation of the STING-TBK1-IRF3 pathway in DCs. Taken together, our findings suggest that Ad-IL15 is a candidate for cancer immunotherapy that promotes immune cell activation and infiltration, tumor vascular normalization and tertiary lymphoid structure formation in the TME.

Molecular underpinnings of glandular tropism in metastatic clear cell renal cell carcinoma: therapeutic implications

BACKGROUND

Glandular metastases (GM) have been associated with improved survival in metastatic clear cell renal cell carcinoma (m-ccRCC). We aimed to molecularly characterize m-ccRCC with GM.

MATERIAL AND METHODS

We performed a retrospective cohort study on all m-ccRCC patients with available tissue at our institution, diagnosed with metastatic disease from 2000 to 2019. We determined previously described angiogenesis- and immune-related gene expression signatures (GES) and ccrcc molecular subtypes through whole transcriptome RNA sequencing of primary tumors and metastases. We tested differences in GES and molecular subtypes across groups and studied overall (OS) and progression-free survival (PFS) using Kaplan-Meier survival analysis and Cox regression models.

RESULTS

Primary tumors of patients who developed GM (n = 55) had higher IMmotion Angio (p < 0.001) and JAVELIN Angio (p = 0.003) GES as well as a higher proportion of angiogenic ccrcc2 molecular subtypes (p = 0.008) than primary tumors of patients with non-GM (n = 128). Metastatic lesions in glandular organs (n = 32) also had higher IMmotion Angio (p = 0.008) and JAVELIN Angio (p = 0.02) GES and were more frequently of the ccrcc2 molecular subtype (p = 0.03), compared to metastatic lesions in non-glandular organs in patients who did not develop any GM (n = 231), but not compared to metastatic lesions in non-glandular organs in patients who also developed GM (n = 18). Patients with GM had better OS (HR 0.49, p < 0.001) and PFS on first-line vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) (HR 0.64, p = 0.045) than patients with non-GM. PFS on first- or any-line immuno-oncology (IO) was not different. IMmotion Angio, JAVELIN Angio GES, and ccrcc2 molecular subtype were associated with better OS and PFS on first-line VEGFR-TKIs, but not PFS on first or any-line IO.

CONCLUSIONS

Patients with m-ccRCC who develop GM are molecularly characterized by heightened angiogenesis, translating into better prognosis and better outcomes on VEGFR-TKIs, but not IO. Based on these findings, VEGFR-TKIs should be included in the first-line treatment of m-ccRCC patients with GM.

Modeling fusion gene-associated sarcoma: Advantages for understanding sarcoma biology and pathology

Disease-specific gene fusions are reportedly major driver mutations in approximately 30% of bone and soft tissue sarcomas. Most fusion genes encode transcription factors or co-factors that regulate downstream target genes, altering cell growth, lineage commitment, and differentiation. Given the limitations of investigating their functions in vitro, the generation of mouse models expressing fusion genes in the appropriate cellular lineages is pivotal. Therefore, we generated a series of mouse models by introducing fusion genes into embryonic mesenchymal progenitors. This review describes mouse models of Ewing, synovial, alveolar soft part, and CIC-rearranged sarcomas. Furthermore, we describe the similarities between these models and their human counterparts. These models provide remarkable advantages to identify cells-of-origin, specific collaborators of fusion genes, angiogenesis key factors, or diagnostic biomarkers. Finally, we discuss the relationship between fusion proteins and the epigenetic background as well as the possible role of the super-enhancers.

Vascular reconstitution in the tumor for more effective tumor immunotherapy

It has been widely accepted that the regulation of the tumor microenvironment is an important strategy in cancer treatment. Particularly, control of the tumor vasculature has been suggested to be critical for antitumor immunotherapy. Effectiveness of cancer immunotherapy depends on the quality and quantity of immune cells infiltrating into tumor tissues, which may be affected by the status of the tumor vasculature. Under physiological conditions, immune cells migrate from the intravascular lumen into the parenchyma especially by passing through the vascular wall of venulae. Extravasation of immune cells is induced from venulae where endothelial cells (ECs) are fully covered with pericytes from the basal side. Interaction of pericytes with ECs contributes to immune cell extravasation by several steps, ie, adhesion of immune cells to intraluminal ECs, transmigration, and chemotaxis of immune cells. Blood vessels are structurally immature and non‐functional in tumors, and therefore, induction of maturation in the tumor vasculature is a promising strategy for effective cancer therapies and is relevant not only for immune cell migration but also drug delivery.