Multiplexed Spatial Imaging at the Single-Cell Level Reveals Mutually Exclusive Expression of B7 Family Proteins.

Targeting novel inhibitory ligands beyond anti-PD-1 and PD-L1 and CTLA-4 therapies is essential for the next decade of the immunotherapy era. Agents for the B7 family molecules B7-H3, B7-H4, and B7-H5 are emerging in clinical trial phases; therefore, further accumulation of evidence from both clinical and basic aspects is vital. Here, we applied a 7-color multiplexed imaging technique to analyze the profile of B7 family B7-H3/B7-H4/B7-H5 expression, in addition to PD-L1, and the spatial characteristics of immune cell infiltrates in urothelial carcinoma (UC). The results revealed that B7-H3 and B7-H4 were mainly expressed on tumor cells and B7-H5 on immune cells in UC, and most of the B7-H3/B7-H4/B7-H5-positive cells were mutually exclusive with PD-L1-positive cells. Also, the expression of B7-H4 was elevated in patients with advanced pathologic stages, and high B7-H4 expression was a significant factor affecting overall mortality following surgery in UC. Furthermore, spatial analysis revealed that the distance from the B7-H4+ cells to the nearest CD8+ cells was markedly far compared with other B7 family-positive tumor cells. Interestingly, the distance from B7-H4+ cells to the nearest CD8+ cells was significantly farther in patients dying from cancer after surgery or immune checkpoint inhibitors compared with cancer survivors; thus, high B7-H4 expression in tumor cells may inhibit CD8 infiltration into the tumor space and that B7-H4-positive cells form a specific spatial niche. In summary, we performed a comprehensive evaluation of B7 family member expression and found that the spatial distribution of B7-H4 suggests the potentially useful role of combination blockade with both B7-H4 and the current anti-PD-1/PD-L1 axis in the treatment of UC.

Heterozygous mutations in the straitjacket region of the latency-associated peptide domain of TGFB2 cause Camurati-Engelmann disease type II.

Camurati-Engelmann disease (CED) is an autosomal dominant bone dysplasia characterized by progressive hyperostosis of the skull base and diaphyses of the long bones. CED is further divided into two subtypes, CED1 and CED2, according to the presence or absence of TGFB1 mutations, respectively. In this study, we used exome sequencing to investigate the genetic cause of CED2 in three pedigrees and identified two de novo heterozygous mutations in TGFB2 among the three patients. Both mutations were located in the region of the gene encoding the straitjacket subdomain of the latency-associated peptide (LAP) of pro-TGF-ß2. Structural simulations of the mutant LAPs suggested that the mutations could cause significant conformational changes and lead to a reduction in TGF-ß2 inactivation. An activity assay confirmed a significant increase in TGF-ß2/SMAD signaling. In vitro osteogenic differentiation experiment using iPS cells from one of the CED2 patients showed significantly enhanced ossification, suggesting that the pathogenic mechanism of CED2 is increased activation of TGF-ß2 by loss-of-function of the LAP. These results, in combination with the difference in hyperostosis patterns between CED1 and CED2, suggest distinct functions between TGFB1 and TGFB2 in human skeletal development and homeostasis.

Mitochondrial Responses to Sublethal Doxorubicin in H9c2 Cardiomyocytes: The Role of Phosphorylated CaMKII.

Background: Doxorubicin (Dox) is effective against different types of cancers, but it poses cardiotoxic side effects, frequently resulting in irreversible heart failure. However, the complexities surrounding this cardiotoxicity, especially at sublethal dosages, remain to be fully elucidated. We investigated early cellular disruptions in response to sublethal Dox, with a specific emphasis on the role of phosphorylated calcium/calmodulin-dependent protein kinase II (CaMKII) in initiating mitochondrial dysfunction. Methods: This study utilized the H9c2 cardiomyocyte model to identify a sublethal concentration of Dox and investigate its impact on mitochondrial health using markers such as mitochondrial membrane potential (MMP), mitophagy initiation, and mitochondrial calcium dynamics. We examined the roles of and interactions between CaMKII, dynamin-related protein 1 (Drp1), and the mitochondrial calcium uniporter (MCU) in Dox-induced mitochondrial disruption using specific inhibitors, such as KN-93, Mdivi-1, and Ru360, respectively. Results: Exposure to a sublethal dose of Dox reduced the MMP red-to-green fluorescence ratio in H9c2 cells by 40.6% compared with vehicle, and increased the proportion of cells undergoing mitophagy from negligible levels compared with vehicle to 62.2%. Mitochondrial calcium levels also increased by 8.7-fold compared with the vehicle group. Notably, the activation of CaMKII, particularly its phosphorylated form, was pivotal in driving these mitochondrial changes, as inhibition using KN-93 restored MMP and decreased mitophagy. However, inhibition of Drp1 and MCU functions had a limited impact on the observed mitochondrial disruptions. Conclusion: Sublethal administration of Dox is closely linked to CaMKII activation through phosphorylation, emphasizing its pivotal role in early mitochondrial disruption. These findings present a promising direction for developing therapeutic strategies that may alleviate the cardiotoxic effects of Dox, potentially increasing its clinical efficacy.

Reinforced antimyeloma therapy via dual-lymphoid activation mediated by a panel of antibodies armed with bridging-BiTE.

Immunotherapy using bispecific antibodies including bispecific T-cell engager (BiTE) has the potential to enhance the efficacy of treatment for relapsed/refractory multiple myeloma. However, myeloma may still recur after treatment because of downregulation of a target antigen and/or myeloma cell heterogeneity. To strengthen immunotherapy for myeloma while overcoming its characteristics, we have newly developed a BiTE-based modality, referred to as bridging-BiTE (B-BiTE). B-BiTE was able to bind to both a human immunoglobulin G-Fc domain and the CD3 molecule. Clinically available monoclonal antibodies (mAbs) were bound with B-BiTE before administration, and the mAb/B-BiTE complex induced antitumor T-cell responses successfully while preserving and supporting natural killer cell reactivity, resulting in enhanced antimyeloma effects via dual-lymphoid activation. In contrast, any unwanted off-target immune-cell reactivity mediated by mAb/B-BiTE complexes or B-BiTE itself appeared not to be observed in vitro and in vivo. Importantly, sequential immunotherapy using 2 different mAb/B-BiTE complexes appeared to circumvent myeloma cell antigen escape, and further augmented immune responses to myeloma relative to those induced by mAb/B-BiTE monotherapy or sequential therapy with 2 mAbs in the absence of B-BiTE. Therefore, this modality facilitates easy and prompt generation of a broad panel of bispecific antibodies that can induce deep and durable antitumor responses in the presence of clinically available mAbs, supporting further advancement of reinforced immunotherapy for multiple myeloma and other refractory hematologic malignancies.

Epstein-Barr virus reactivation in peripheral B lymphocytes induces IgM-type thyrotropin receptor autoantibody production in patients with Graves' disease.

Epstein-Barr virus (EBV) is a human herpes virus that latently infects B lymphocytes. When EBV is reactivated, host B cells differentiate into plasma cells and produce IgM-dominant antibodies as well as many progeny virions. The aims of the present study were to confirm the IgM dominance of thyrotropin-receptor antibodies (TRAbs) produced by EBV reactivation and investigate the roles of TRAb-IgM in Graves' disease. Peripheral blood mononuclear cells (PBMCs) containing TRAb-producing cells were stimulated for EBV reactivation, and TRAb-IgM and TRAb-IgG were measured by ELISA. TRAb-IgM were purified and TSH-binding inhibitory activities were assessed using a radio-receptor assay. Porcine thyroid follicular epithelial cells were cultured with TRAb-IgM and/or complements to measure the intracellular levels of cAMP and the amount of LDH released. TRAb-IgM/TRAb-IgG (the MG ratio) was examined in sequential serum samples of Graves' disease and compared among groups of thyroid function. The results obtained showed that IgM-dominant TRAb production was induced by EBV reactivation. TRAb-IgM did not inhibit TSH binding to TSH receptors and did not transduce hormone-producing signals. However, it destroyed thyroid follicular epithelial cells with complements. The MG ratio was significantly higher in samples of hyperthyroidism or hypothyroidism than in those with normal function or in healthy controls. A close relationship was observed between TRAb-IgM produced by EBV reactivation and the development and exacerbation of Graves' disease. The present results provide novel insights for the development of prophylaxis and therapeutics for Graves' disease.

[The mechanisms of glucose transporter type 4 translocation regulated by insulin receptor signaling].

Insulin-regulated glucose transport is dependent on glucose transporter GLUT4 translocation to the plasma membrane, which incorporates glucose into the cells, mainly in adipose tissue and skeletal muscle. Insulin receptor signaling can stimulate GLUT4 vesicle transport from perinuclear pool to the plasma membrane via the vesicle transport machinery. At first, insulin signaling is divided to the multiple pathways, such as Akt/PKB and PKC-zeta/lambda. Subsequently, PKC-zeta/lambda activates KIF3, motor protein based on microtubules, and sequentially Akt/PKB activates Myosin-Va, motor protein based on actin filaments. KIF3 motor moves GLUT4 vesicles from perinuclear pool to the end of microtubules, and Myosin-Va transports GLUT4 vesicles from the end of microtubules to the plasma membrane. Here we indicate the machinery of insulin-regulated GLUT4 vesicle translocation, showing that these motor proteins are the destinations of insulin receptor signaling to regulate glucose transport into the cells.

Single-Cell Phenotyping of CD73 Expression Reveals the Diversity of the Tumor Immune Microenvironment and Reflects the Prognosis of Bladder Cancer.

The cutting edge of cancer immunotherapy extends to ecto-5'-nucleotidase (CD73), a cell membrane enzyme that targets the metabolism of extracellular adenosine. We herein focused on the expression of CD73 to clarify the state of CD73 positivity in cancer immunity and tumor microenvironment, thereby revealing a new survival predictor for patients with bladder cancer (BCa). We used clinical tissue microarrays of human BCa and simultaneously performed the fluorescent staining of cell type-specific markers (CD3, CD8, Foxp3, programmed cell death protein 1, and programmed death-ligand 1 [PD-L1]) and CD73 together with DAPI for nuclear staining. In total, 156 participants were included. Multiplexed cellular imaging revealed a unique interaction between CD73 expression and CD8+ cytotoxic T cells (CTLs) and Foxp3+ regulatory T (Treg) cells in human BCa, showing the high infiltration of CD8+CD73+ CTLs and Foxp3+CD73+ Treg cells in tumors to be associated with tumorigenesis and poor prognosis in BCa. Interestingly, from a biomarker perspective, the high infiltration of CD73+ Treg cells in tumors was identified as an independent risk factor for overall survival in addition to clinicopathologic features. Regarding the relationship between immune checkpoint molecules and CD73 expression, both CD73+ CTLs and CD73+ Treg cells tended to coexpress programmed cell death protein 1 as tumor invasiveness and nuclear grade increased. Additionally, they may occupy a spatial niche located distantly from PD-L1+ cells in tumors to interfere less with the cancerous effects of PD-L1+ cells. In conclusion, the present results on the status of CD73 in cancer immunity suggest that CD73 expression on specific T-cell types has a negative immunoregulatory function. These findings may provide further insights into the immunobiological landscape of BCa, which may be translationally linked to improvements in future immunotherapy practice.

Cell-matrix interface regulates dormancy in human colon cancer stem cells.

Cancer relapse after chemotherapy remains a main cause of cancer-related death. Although the relapse is thought to result from the propagation of resident cancer stem cells1, a lack of experimental platforms that enable the prospective analysis of cancer stem cell dynamics with sufficient spatiotemporal resolution has hindered the testing of this hypothesis. Here we develop a live genetic lineage-tracing system that allows the longitudinal tracking of individual cells in xenotransplanted human colorectal cancer organoids, and identify LGR5+ cancer stem cells that exhibit a dormant behaviour in a chemo-naive state. Dormant LGR5+ cells are marked by the expression of p27, and intravital imaging provides direct evidence of the persistence of LGR5+p27+ cells during chemotherapy, followed by clonal expansion. Transcriptome analysis reveals that COL17A1-a cell-adhesion molecule that strengthens hemidesmosomes-is upregulated in dormant LGR5+p27+ cells. Organoids in which COL17A1 is knocked out lose the dormant LGR5+p27+ subpopulation and become sensitive to chemotherapy, which suggests that the cell-matrix interface has a role in the maintenance of dormancy. Chemotherapy disrupts COL17A1 and breaks the dormancy in LGR5+p27+ cells through FAK-YAP activation. Abrogation of YAP signalling prevents chemoresistant cells from exiting dormancy and delays the regrowth of tumours, highlighting the therapeutic potential of YAP inhibition in preventing cancer relapse. These results offer a viable therapeutic approach to overcome the refractoriness of human colorectal cancer to conventional chemotherapy.

Reduced dynamic loads due to hip dislocation induce acetabular cartilage degeneration by IL-6 and MMP3 via the STAT3/periostin/NF-κB axis.

Developmental dysplasia of the hip (DDH) is characterized by anatomical abnormalities of the hip joint, ranging from mild acetabular dysplasia to hip subluxation and eventually dislocation. The mechanism underlying the cartilage degeneration of the hip joints exposed to reduced dynamic loads due to hip dislocation remains unknown. We established a rodent hip dislocation (disarticulation; DA) model of DDH (DA-DDH rats and mice) by swaddling. Expression levels of periostin (Postn) and catabolic factors, such as interleukin-6 (IL-6) and matrix metalloproteinase 3 (Mmp3), increased and those of chondrogenic markers decreased in the acetabular cartilage of the DA-DDH models. Postn induced IL-6 and Mmp3 expression in chondrocytes through integrin αVß3, focal adhesion kinase, Src, and nuclear factor-κB (NF-κB) signaling. The microgravity environment created by a random positioning machine induced Postn expression in chondrocytes through signal transducer and activator of transcription 3 (STAT3) signaling. IL-6 stimulated Postn expression via STAT3 signaling. Furthermore, cartilage degeneration was suppressed in the acetabulum of Postn-/- DA-DDH mice compared with that in the acetabulum of wild type DA-DDH mice. In summary, reduced dynamic loads due to hip dislocation induced acetabular cartilage degeneration via IL-6 and MMP3 through STAT3/periostin/NF-κB signaling in the rodent DA-DDH models.

Computer-Aided Detection of Quantitative Signatures for Breast Fibroepithelial Tumors Using Label-Free Multi-Photon Imaging.

Fibroadenomas (FAs) and phyllodes tumors (PTs) are major benign breast tumors, pathologically classified as fibroepithelial tumors. Although the clinical management of PTs differs from FAs, distinction by core needle biopsy diagnoses is still challenging. Here, a combined technique of label-free imaging with multi-photon microscopy and artificial intelligence was applied to detect quantitative signatures that differentiate fibroepithelial lesions. Multi-photon excited autofluorescence and second harmonic generation (SHG) signals were detected in tissue sections. A pixel-wise semantic segmentation method using a deep learning framework was used to separate epithelial and stromal regions automatically. The epithelial to stromal area ratio and the collagen SHG signal strength were investigated for their ability to distinguish fibroepithelial lesions. An image segmentation analysis with a pixel-wise semantic segmentation framework using a deep convolutional neural network showed the accurate separation of epithelial and stromal regions. A further investigation, to determine if scoring the epithelial to stromal area ratio and the SHG signal strength within the stromal area could be a marker for differentiating fibroepithelial tumors, showed accurate classification. Therefore, molecular and morphological changes, detected through the assistance of computational and label-free multi-photon imaging techniques, enable us to propose quantitative signatures for epithelial and stromal alterations in breast tissues.

Differences in interaction lead to the formation of different types of insulin amyloid.

Insulin balls, localized insulin amyloids formed at the site of repeated insulin injections in patients with diabetes, cause poor glycemic control and cytotoxicity. Our previous study has shown that insulin forms two types of amyloids; toxic amyloid formed from the intact insulin ((i)-amyloid) and less-toxic amyloid formed in the presence of the reducing reagent TCEP ((r)-amyloid), suggesting insulin amyloid polymorphism. However, the differences in the formation mechanism and cytotoxicity expression are still unclear. Herein, we demonstrate that the liquid droplets, which are stabilized by electrostatic interactions, appear only in the process of toxic (i)-amyloid formation, but not in the less-toxic (r)-amyloid formation process. The effect of various additives such as arginine, 1,6-hexanediol, and salts on amyloid formation was also examined to investigate interactions that are important for amyloid formation. Our results indicate that the maturation processes of these two amyloids were significantly different, whereas the nucleation by hydrophobic interactions was similar. These results also suggest the difference in the formation mechanism of two different insulin amyloids is attributed to the difference in the intermolecular interactions and could be correlated with the cytotoxicity.

Aryl hydrocarbon receptor signals in epithelial cells govern the recruitment and location of Helios+ Tregs in the gut.

CD4+Foxp3+ regulatory T cells (Tregs) are essential for homeostasis in the colon, but the mechanism by which local environmental cues determine the localization of colonic Tregs is unclear. Here, we administer indigo naturalis (IN), a nontoxic phytochemical aryl hydrocarbon receptor (AhR) agonist used for treating patients with ulcerative colitis (UC) in Asia, and we show that IN increases Helios+ Tregs and MHC class II+ epithelial cells (ECs) in the colon. Interactions between Tregs and MHC class II+ ECs occur mainly near the crypt bottom in the steady state, whereas Tregs dramatically increase and shift toward the crypt top following IN treatment. Moreover, the number of CD25+ T cells is increased near the surface of ECs in IN-treated UC patients compared with that in patients treated with other therapies. We also highlight additional AhR-signaling mechanisms in intestinal ECs that determine the accumulation and localization of Helios+ Tregs in the colon.

Tumor-targeted fluorescence labeling systems for cancer diagnosis and treatment.

Conventional imaging techniques are available for clinical identification of tumor sites. However, detecting metastatic tumor cells that are spreading from primary tumor sites using conventional imaging techniques remains difficult. In contrast, fluorescence-based labeling systems are useful tools for detecting tumor cells at the single-cell level in cancer research. The ability to detect fluorescent-labeled tumor cells enables investigations of the biodistribution of tumor cells for the diagnosis and treatment of cancer. For example, the presence of fluorescent tumor cells in the peripheral blood of cancer patients is a predictive biomarker for early diagnosis of distant metastasis. The elimination of fluorescent tumor cells without damaging normal tissues is ideal for minimally invasive treatment of cancer. To capture fluorescent tumor cells within normal tissues, however, tumor-specific activated target molecules are needed. This review focuses on recent advances in tumor-targeted fluorescence labeling systems, in which indirect reporter labeling using tumor-specific promoters is applied to fluorescence labeling of tumor cells for the diagnosis and treatment of cancer. Telomerase promoter-dependent fluorescence labeling using replication-competent viral vectors produces fluorescent proteins that can be used to detect and eliminate telomerase-positive tumor cells. Tissue-specific promoter-dependent fluorescence labeling enables identification of specific tumor cells. Vimentin promoter-dependent fluorescence labeling is a useful tool for identifying tumor cells that undergo epithelial-mesenchymal transition (EMT). The evaluation of tumor cells undergoing EMT is important for accurately assessing metastatic potential. Thus, tumor-targeted fluorescence labeling systems represent novel platforms that enable the capture of tumor cells for the diagnosis and treatment of cancer.

TGFß selects for pro-stemness over pro-invasive phenotypes during cancer cell epithelial-mesenchymal transition.

Transforming growth factor ß (TGFß) induces epithelial-mesenchymal transition (EMT), which correlates with stemness and invasiveness. Mesenchymal-epithelial transition (MET) is induced by TGFß withdrawal and correlates with metastatic colonization. Whether TGFß promotes stemness and invasiveness simultaneously via EMT remains unclear. We established a breast cancer cell model expressing red fluorescent protein (RFP) under the E-cadherin promoter. In 2D cultures, TGFß induced EMT, generating RFPlow cells with a mesenchymal transcriptome, and regained RFP, with an epithelial transcriptome, after MET induced by TGFß withdrawal. RFPlow cells generated robust mammospheres, with epithelio-mesenchymal cell surface features. Mammospheres that were forced to adhere generated migratory cells, devoid of RFP, a phenotype which was inhibited by a TGFß receptor kinase inhibitor. Further stimulation of RFPlow mammospheres with TGFß suppressed the generation of motile cells, but enhanced mammosphere growth. Accordingly, mammary fat-pad-transplanted mammospheres, in the absence of exogenous TGFß treatment, established lung metastases with evident MET (RFPhigh cells). In contrast, TGFß-treated mammospheres revealed high tumour-initiating capacity, but limited metastatic potential. Thus, the biological context of partial EMT and MET allows TGFß to differentiate between pro-stemness and pro-invasive phenotypes.

The sodium-glucose cotransporter 2 inhibitor ipragliflozin improves liver function and insulin resistance in Japanese patients with type 2 diabetes.

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment is a therapeutic approach for type 2 diabetes mellitus (T2DM). Some reports have shown that SGLT2i treatment improves insulin resistance; however, few studies have evaluated insulin resistance by the glucose clamp method. Hepatic insulin clearance (HIC) is a new pathophysiological mechanism of T2DM. The effect of SGLT2i treatment on hepatic insulin clearance and insulin resistance is not well known. We investigated the effect of SGLT2i treatment on insulin resistance, insulin secretion, incretin levels, body composition, and hepatic insulin clearance. We conducted a meal tolerance test (MTT) and a hyperinsulinemic-euglycemic clamp test in 9 T2DM patients. Ipragliflozin (50 mg/day) was administered, and the MTT and clamp test were performed after 4 months. We calculated HIC as the postprandial C-peptide AUC-to-insulin AUC ratio. We also measured GLP-1, GIP, and glucagon levels during the MTT. Body weight and HbA1c were decreased, although not significantly, after 4 months of treatment. Postprandial glucose, fasting insulin and postprandial insulin were significantly decreased. Insulin resistance with the glucose clamp was not changed, but the HOMA-IR and insulin sensitivity indices were significantly improved. Incretin and glucagon levels were not changed. Hepatic insulin clearance was significantly increased, but whole-body insulin clearance was not changed. The FIB-4 index and fatty liver index were significantly reduced. The HOMA-beta and insulinogenic indices were not changed, but the C-peptide index was significantly increased. Although the number of patients was small, these results suggested that SGLT2i treatment improved liver function, decreased hepatic insulin resistance, and increased hepatic insulin clearance, despite the small weight reduction.

Synthesis and photophysical properties of a new push-pull pyrene dye with green-to-far-red emission and its application to human cellular and skin tissue imaging.

Herein, we discuss a new pyrene-based push-pull dye (PC) and our investigation of its photophysical properties and applicability to biological studies. The newly synthesized dye exhibits highly polarity-sensitive fluorescence over a significantly wide range (i.e., the green to far-red region), accompanied by high fluorescence quantum yields (ΦFL > 0.70 in most organic solvents) and superior photostability to that of the commonly used Nile Red (NR) dye, which also fluoresces in the green to red region. When human prostate cancer cells stained with PC were imaged using a confocal laser scanning fluorescence microscope, PC was found to selectively stain the lipid droplets. Under the cell conditions where the formation of droplets was inhibited, PC could be distributed to both the remaining droplets and the intercellular membranes, which could be distinguished based on the fluorescence solvatochromic function of PC. Furthermore, PC efficiently stained normal human skin tissue blocks treated with a transparency-enhancing agent and enabled clear visualization of individual cells in each tissue architecture by means of two-photon fluorescence microscopy (2PM). Interestingly, PC provides bright 2PM images under tissue-penetrative 960 nm excitation, realizing much clearer and deeper tissue imaging than conventional pyrene dyes and NR. These results suggest that PC could replace several commonly used dyes in various biological applications, particularly the rapid and accurate diagnosis of tissue diseases, typified by biopsy.

Profiling the inhibitory receptors LAG-3, TIM-3, and TIGIT in renal cell carcinoma reveals malignancy.

A cutting edge therapy for future immuno-oncology is targeting a new series of inhibitory receptors (IRs): LAG-3, TIM-3, and TIGIT. Both immunogenomic analyses and diagnostic platforms to distinguish candidates and predict good responders to these IR-related agents are vital in clinical pathology. By applying an automated single-cell count for immunolabelled LAG-3, TIM-3, and TIGIT, we reveal that individual IR levels with exclusive domination in each tumour can serve as valid biomarkers for profiling human renal cell carcinoma (RCC). We uncover the immunogenomic landscape associated with individual IR levels in human RCC tumours with metastases in various organs and histological subtypes. We then externally validate our results and devise a workflow with optimal biomarker cut-offs for discriminating the LAG-3, TIM-3, and TIGIT tumour profiles. The discrimination of LAG-3, TIM-3, and TIGIT profiles in tumours may have a broad impact on investigations of immunotherapy responses after targeting a new series of IRs.

Multiplexed single-cell pathology reveals the association of CD8 T-cell heterogeneity with prognostic outcomes in renal cell carcinoma.

Despite the high sensitivity of renal cell carcinoma (RCC) to immunotherapy, RCC has been recognized as an unusual disease in which CD8+ T-cell infiltration into the tumor beds is related to a poor prognosis. To approach the inner landscape of immunobiology of RCC, we performed multiplexed seven-color immunohistochemistry (CD8, CD39, PD-1, Foxp3, PD-L1, and pan-cytokeratin AE1/AE3 with DAPI), which revealed the automated single-cell counts and calculations of individual cell-to-cell distances. In total, 186 subjects were included, in which CD39 was used as a marker for distinguishing tumor-specific (CD39+) and bystander (CD39-) T-cells. Our clear cell RCC cohort also revealed a poor prognosis if the tumor showed increased CD8+ T-cell infiltration. Intratumoral CD8+CD39+ T-cells as well as their exhausted CD8+CD39+PD-1+ T-cells in the central tumor areas enabled the subgrouping of patients according to malignancy. Analysis using specimens post-antiangiogenic treatment revealed a dramatic increase in proliferative Treg fraction Foxp3+PD-1+ cells, suggesting a potential mechanism of hyperprogressive disease after uses of anti-PD-1 antibody. Our cell-by-cell study platform provided spatial information on tumors, where bystander CD8+CD39- T-cells were dominant in the invasive margin areas. We uncovered a potential interaction between CD8+CD39+PD-1+ T-cells and Foxp3+PD-1+ Treg cells due to cell-to-cell proximity, forming a spatial niche more specialized in immunosuppression under PD-1 blockade. A paradigm shift to the immunosuppressive environment was more obvious in metastatic lesions; rather the infiltration of Foxp3+ and Foxp3+PD-1+ Treg cells was more pronounced. With this multiplexed single-cell pathology technique, we revealed further insight into the immunobiological standing of RCC.