The tumor microenvironment in renal cell cancer

BAG3 as a novel prognostic biomarker in kidney renal clear cell carcinoma correlating with immune infiltrates

PURPOSE

BCL-2-associated athanogene 3 (BAG3) is an anti-apoptotic protein that plays an essential role in the onset and progression of multiple cancer types. However, the clinical significance of BAG3 in kidney renal clear cell carcinoma (KIRC) remains unclear.

METHODS

Using Tumor IMmune Estimation Resource (TIMER), The Cancer Genome Atlas (TCGA), and Gene Expression Omnibus (GEO) database, we explored the expression, prognostic value, and clinical correlations of BAG3 in KIRC. In addition, immunohistochemistry (IHC) of HKH cohort further validated the expression of BAG3 in KIRC and its impact on prognosis. Gene Set Cancer Analysis (GSCA) was utilized to scrutinize the prognostic value of BAG3 methylation. Gene Ontology (GO) term analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene set enrichment analysis (GSEA) were used to identify potential biological functions of BAG3 in KIRC. Single-sample gene set enrichment analysis (ssGSEA) was performed to confirm the correlation between BAG3 expression and immune cell infiltration.

RESULTS

BAG3 mRNA expression and protein expression were significantly downregulated in KIRC tissues compared to normal kidney tissues, associated with adverse clinical-pathological factors and poor clinical prognosis. Multivariate Cox regression analysis indicated that low expression of BAG3 was an independent prognostic factor in KIRC patients. GSEA analysis showed that BAG3 is mainly involved in DNA methylation and the immune-related pathways in KIRC. In addition, the expression of BAG3 is closely related to immune cell infiltration and immune cell marker set.

CONCLUSION

BAG3 might be a potential therapeutic target and valuable prognostic biomarker of KIRC and is closely related to immune cell infiltration.

Mechanisms of tyrosine kinase inhibitor resistance in renal cell carcinoma

Renal cell carcinoma (RCC), the most prevalent type of kidney cancer, is a significant cause of cancer morbidity and mortality worldwide. Antiangiogenic tyrosine kinase inhibitors (TKIs), in combination with immune checkpoint inhibitors (ICIs), are among the first-line treatment options for patients with advanced RCC. These therapies target the vascular endothelial growth factor receptor (VEGFR) tyrosine kinase pathway and other kinases crucial to cancer proliferation, survival, and metastasis. TKIs have yielded substantial improvements in progression-free survival (PFS) and overall survival (OS) for patients with advanced RCC. However, nearly all patients eventually progress on these drugs as resistance develops. This review provides an overview of TKI resistance in RCC and explores different mechanisms of resistance, including upregulation of alternative proangiogenic pathways, epithelial-mesenchymal transition (EMT), decreased intracellular drug concentrations due to efflux pumps and lysosomal sequestration, alterations in the tumor microenvironment including bone marrow-derived cells (BMDCs) and tumor-associated fibroblasts (TAFs), and genetic factors such as single nucleotide polymorphisms (SNPs). A comprehensive understanding of these mechanisms opens the door to the development of innovative therapeutic approaches that can effectively overcome TKI resistance, thereby improving outcomes for patients with advanced RCC.

Prognostic value of neutrophil extracellular trap signature in clear cell renal cell carcinoma

Introduction

Clear cell renal cell carcinoma (ccRCC) is the most prevalent type of urological carcinoma. Although targeted therapy and immunotherapy are usually employed, they often result in primary and acquired resistance. There is currently a lack of dependable biomarkers that can accurately anticipate the prognosis of ccRCC. Recent research has indicated the critical role of neutrophil extracellular traps (NETs) in the development, metastasis, and immune evasion of cancer. The aim of this study was to explore the value of NETs in the development and prognosis of ccRCC.

Methods

Clinical features and genetic expression information of ccRCC patients were acquired from The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC) and E-MTAB-1980 database. NETs-related gene set were obtained from previous studies. A NETs-related gene signature was constructed based on TCGA data and validated using ICGC and E-MTAB-1980 databases. Furthermore, the immune microenvironment and responsiveness to anticancer medications in ccRCC patients with varying levels of NETs risks were investigated.

Results

A total of 31 NET-related genes were differently expressed between normal kidney and ccRCC tissues. 17 out of 31 were significantly associated with overall survival. After LASSO Cox regression analysis, nine NETs-related genes were enrolled to construct the NETs prognosis signature, and all the ccRCC patients from TCGA were divided into low and high risk group. This signature demonstrated excellent performance in predicting the overall survival of TCGA patients as well as the validation ICGC and E-MTAB-1980 patients. Additionally, the NETs signature was significantly correlated with immune infiltration and drug sensitivity.

Conclusions

The NETs signature established by the current study has prognostic significance in ccRCC, and may serve as a useful biomarker for patient stratification and treatment decisions. Further validation and clinical studies are required to fully translate these findings into clinical practice.

Mechanisms and clinical implications in renal carcinoma resistance: narrative review of immune checkpoint inhibitors

Clear cell renal cell carcinoma (ccRCC) is the most common histological subtype of renal cell carcinoma. The prognosis for patients with ccRCC has improved over recent years with the use of combination therapies with an anti-programmed death-1 (PD-1) backbone. This has enhanced the quality of life and life expectancy of patients with this disease. Unfortunately, not all patients benefit; eventually, most patients will develop resistance to therapy and progress. Recent molecular, biochemical, and immunological research has extensively researched anti-angiogenic and immune-based treatment resistance mechanisms. This analysis offers an overview of the principles underpinning the resistance pathways related to immune checkpoint inhibitors (ICIs). Additionally, novel approaches to overcome resistance that may be considered for the trial context are discussed.

A novel prognostic signature of chemokines for survival and immune infiltration in kidney renal clear cell carcinoma

Objective: Studies have revealed the alteration of chemokines in the tumour microenvironment in renal clear cell carcinoma (KIRC), which is closely related with immune infiltration and the prognosis of patients with KIRC. This research aims to comprehensively clarify the signature of chemokines in KIRC and the correlation between chemokines and immune infiltration in the TME of KIRC. Methods: The chemokine expression in KIRC were investigated by using multiple multiomics and bioinformatics tools. Hub-chemokines that were significantly related with the cancer stage and survival were identified. The role of hub-chemokines in the tumor microenvironment of KIRC was further assessed by using enrichment analysis, cancer-related pathway and immune infiltration analysis. Results: A total of 20 chemokines were significantly elevated in KIRC. Based on the correlation with KIRC stages and survival, 13 hub-chemokines were identified. Among the hub-chemokines, the high expression of CXCL2, CXCL5 and CXCL13 were related with worse survival of KIRC patients. The hub-chemokines were associated with the activation of multiple cancer-related signaling pathways. The functions of hub-chemokines were mainly enriched in chemokine-mediated signaling pathway, immunocytes chemotaxis and chemokine activity. CCL4, CCL5, CXCL9, CXCL10 and CXCL11 were related with various types immune infiltration such as CD8⁺T cell, neutrophil, B cell and dendritic cell. Using the hub-chemokine CXCL10, multiple immune checkpoints including LAG3, CTLA-4 and PD-1 were identified. Conclusion: Our research sheds light on the chemokines and their important role in promoting the tumor microenvironment of KIRC. The findings could provide more data about the prognosis prediction and treatment targets for KIRC.

Tumor lineage-specific immune response in brain metastatic disease: opportunities for targeted immunotherapy regimen?

Metastases in the brain are the most severe and devastating complication of cancer. The incidence of brain metastasis is increasing. Therefore, the need of finding specific druggable targets for brain metastasis is demanding. The aim of this study was to compare the brain (immune) response to brain metastases of the most common tumor lineages, viz., lung adenocarcinoma and breast cancer. Targeted gene expression profiles of 11 brain metastasis of lung adenocarcinoma (BM-LUAD) were compared to 11 brain metastasis of breast cancer (BCBM) using NanoString nCounter PanCancer IO 360™ Panel. The most promising results were validated spatially using the novel GeoMx™ Digital Spatial Profiler (DSP) Technology. Additionally, Immune cell profiles and expression of drug targets were validated by multiplex immunohistochemistry. We found a more active immune response in BM-LUAD as compared to BCBM. In the BM-LUAD, 138 genes were upregulated as compared to BCBM (adj. p ≤ 0.05). Conversely, in BCBM 28 genes were upregulated (adj. p ≤ 0.05). Additionally, genes related to CD45 + cells, T cells, and cytotoxic T cells showed to be expressed higher in BM-LUAD compared to BCBM (adj. p = 0.01, adj. p = 0.023, adj. p = 0.023, respectively). The spatial quantification of the immune cells using the GeoMx DSP technique revealed the significantly higher quantification of CD14 and CD163 in tumor regions of BM-LUAD as compared to BCBM. Importantly, the immune checkpoint VISTA and IDO1 were identified as highly expressed in the BM-LUAD. Multiplex immunohistochemistry confirmed the finding and showed that VISTA is expressed mainly in BM-LUAD tumor cells, CD3 + cells, and to fewer levels in some microglial cells in BM-LUAD. This is the first report on differences in the brain immune response between metastatic tumors of different lineages. We found a far more extensive infiltration of immune cells in BM-LUAD as compared to BCBM. In addition, we found higher expression of VISTA and IDO1 in BM-LUAD. Taken together, targeted immune therapy should be considered to treat patients with BM-LUAD.

A chemokine network of T cell exhaustion and metabolic reprogramming in renal cell carcinoma

Renal cell carcinoma (RCC) is frequently infiltrated by immune cells, a process which is governed by chemokines. CD8+ T cells in the RCC tumor microenvironment (TME) may be exhausted which most likely influence therapy response and survival. The aim of this study was to evaluate chemokine-driven T cell recruitment, T cell exhaustion in the RCC TME, as well as metabolic processes leading to their functional anergy in RCC. Eight publicly available bulk RCC transcriptome collectives (n=1819) and a single cell RNAseq dataset (n=12) were analyzed. Immunodeconvolution, semi-supervised clustering, gene set variation analysis and Monte Carlo-based modeling of metabolic reaction activity were employed. Among 28 chemokine genes available, CXCL9/10/11/CXCR3, CXCL13/CXCR5 and XCL1/XCR1 mRNA expression were significantly increased in RCC compared to normal kidney tissue and also strongly associated with tumor-infiltrating effector memory and central memory CD8+ T cells in all investigated collectives. M1 TAMs, T cells, NK cells as well as tumor cells were identified as the major sources of these chemokines, whereas T cells, B cells and dendritic cells were found to predominantly express the cognate receptors. The cluster of RCCs characterized by high chemokine expression and high CD8+ T cell infiltration displayed a strong activation of IFN/JAK/STAT signaling with elevated expression of multiple T cell exhaustion-associated transcripts. Chemokinehigh RCCs were characterized by metabolic reprogramming, in particular by downregulated OXPHOS and increased IDO1-mediated tryptophan degradation. None of the investigated chemokine genes was significantly associated with survival or response to immunotherapy. We propose a chemokine network that mediates CD8+ T cell recruitment and identify T cell exhaustion, altered energy metabolism and high IDO1 activity as key mechanisms of their suppression. Concomitant targeting of exhaustion pathways and metabolism may pose an effective approach to RCC therapy.

Prognostic biomarker NEIL3 and its association with immune infiltration in renal clear cell carcinoma

Background

Kidney renal clear cell carcinoma (KIRC) is a malignant tumor with a high degree of immune infiltration. Identifying immune biomarkers is essential for the treatment of KIRC. Studies have identified the potential of NEIL3 to modulate the immune microenvironment and promote tumor progression. However, the role of NEIL3 in KIRC remains uncertain. This study was to investigate the effect of NEIL3 on the prognosis and immune infiltration of patients with KIRC.

Methods

TCGA and GEO databases were used to study the expression of NEIL3 in KIRC. Cox regression analysis was used to examine the relationship between the expression of NEIL3 and clinicopathological variables and survival. Furthermore, Gene Set Cancer Analysis (GSCA) was applied to study the impact of NEIL3 methylation on outcomes of KIRC. Through gene ontology (GO) and Gene set enrichment (GSEA) analysis, the biological processes and signal pathways related to NEIL3 expression were identified. In addition, immune infiltration analysis was conducted via CIBERSORT analysis, ssGSEA analysis and TISIDB database.

Results

NEIL3 was overexpressed in KIRC, and it was significantly related with histologic grade, pathologic stage, T stage, M stage, and vital status of KIRC patients (P < 0.001). The expression of NEIL3 was associated with worse outcomes. Univariate and multivariate Cox analysis showed that NEIL3 may be an indicator of adverse outcomes in KIRC. GSEA analysis revealed that NEIL3 may be involved in signal pathways including cell cycle, DNA replication, mismatch repair, P53 signal pathway, and antigen processing and presentation. In addition, immune infiltration analysis showed a positive correlation between NEIL3 expression and multiple immune cells (activated CD8 T cells, activated dendritic cells, myeloid-derived suppressor cells, follicular helper T cells, and regulatory T cells) and immunoinhibitors (PD1, CTLA4, LAG3, TIGHT, IL10, and CD96).

Conclusion

NEIL3 is a potential independent biomarker of KIRC, which is relevant to immune infiltration.

The role of hyaluronan in renal cell carcinoma

Renal cell carcinoma (RCC) is associated with high mortality rates worldwide and survival among RCC patients has not improved significantly in the past few years. A better understanding of the pathogenesis of RCC can enable the development of more effective therapeutic strategies against RCC. Hyaluronan (HA) is a glycosaminoglycan located in the extracellular matrix (ECM) that has several roles in biology, medicine, and physiological processes, such as tissue homeostasis and angiogenesis. Dysregulated HA and its receptors play important roles in fundamental cellular and molecular biology processes such as cell signaling, immune modulation, tumor progression and angiogenesis. There is emerging evidence that alterations in the production of HA regulate RCC development, thereby acting as important biomarkers as well as specific therapeutic targets. Therefore, targeting HA or combining it with other therapies are promising therapeutic strategies. In this Review, we summarize the available data on the role of abnormal regulation of HA and speculate on its potential as a therapeutic target against RCC.

Novel Expression of Thymine Dimers in Renal Cell Carcinoma, Demonstrated through Immunohistochemistry

Despite significant developments in renal cell carcinoma (RCC) detection and molecular pathology, mortality has been steadily rising. Advanced RCC remains an incurable disease. Better clinical management tools, i.e., RCC biomarkers, have yet to emerge. Thymine-dimers (TDs) were traditionally considered photo-dependent pre-mutagenic lesions, occurring exclusively during ultra-violet light exposure. Non-oxidative, direct, and preferential byproducts of DNA photochemical reactions, TDs, have recently shown evidence regarding UVR-independent formation. In this study, we investigate, for the first time, TD expression within RCC tumor tissue and tumor-adjacent healthy renal parenchyma using a TD-targeted IHC monoclonal antibody, clone KTM53. Remarkably, out of the 54 RCCs evaluated, 77.8% showed nuclear TD-expression in RCC tumor tissue and 37% in the tumor-adjacent healthy renal parenchyma. A comprehensive report regarding quantitative/qualitative TD-targeted immunostaining was elaborated. Two main distribution models for TD expression within RCC tumor tissue were identified. Statistical analysis showed significant yet moderate correlations regarding TD-positivity in RCC tissue/tumor-adjacent healthy renal parenchyma and TNM stage at diagnosis/lymphatic dissemination, respectively, indicating possible prognostic relevance. We review possible explanations for UVR-independent TD formation and molecular implications regarding RCC carcinogenesis. Further rigorous molecular analysis is required in order to fully comprehend/validate the biological significance of this newly documented TD expression in RCC.

Immune checkpoint receptor VISTA on immune cells is associated with expression of T-cell exhaustion marker TOX and worse prognosis in renal cell carcinoma with venous tumor thrombus

PURPOSE

The study aimed to determine the expression of VISTA and TOX within venous tumor thrombus and primary clear cell renal cell carcinoma (ccRCC) and to assess their prognostic value.

METHODS

The study enrolled 82 patients with ccRCC and coexisting venous tumor thrombus treated radically from 2012 to 2019 in two tertiary centers. Tissue microarrays were prepared and stained with respective antibodies. The expression of markers was assessed separately on tumor cells (TCs) and/or tumor-associated immune cells (TAICs).

RESULTS

TOX expression was positively correlated with the percentage of VISTA-positive TAICs in venous thrombus (p = 0.011), but not in the primary tumor (p = 0.674). High TOX expression was associated with a higher percentage of PD-L1-positive TAICs in both compartments (p = 0.001, p = 0.011, respectively). Positive expression of VISTA on TAICs was associated with PD-L1 expression on TCs (p = 0.005) and TAICs (p = 0.004) in the primary tumor, and only with PD-L1 on TAICs in thrombus (p = 0.006). The presence of VISTA-positive TAICs in venous thrombus was significantly more common in females (p = 0.034), and positively correlated with metastases (p = 0.028), and tumor necrosis (p = 0.013). The cases with VISTA-positive TAICs in venous tumor thrombi had significantly shorter OS than VISTA-negative cases (p = 0.041).

CONCLUSION

For the first time, we demonstrated the expression of VISTA- and TOX-positive TAICs in the venous tumor thrombus. We found the association between immune checkpoint receptors and T cell exhaustion markers in both tumor mass and venous thrombus. Finally, we demonstrated that abundance of VISTA-positive TAICs in venous tumor thrombus correlates with worse outcomes in ccRCC.

Distinct Predictive Immunogenomic Profiles of Response to Immune Checkpoint Inhibitors and IL2: A Real-world Evidence Study of Patients with Advanced Renal Cancer

Recombinant human high-dose IL2 (HD-IL2; aldesleukin) was one of the first approved immune-oncology agents based upon clinical activity in renal cell carcinoma (RCC) and metastatic melanoma but use was limited due to severe toxicity. Next-generation IL2 agents designed to improve tolerability are in development, increasing the need for future identification of genomic markers of clinical benefit and/or clinical response. In this retrospective study, we report clinical and tumor molecular profiling from patients with metastatic RCC (mRCC) treated with HD-IL2 and compare findings with patients with RCC treated with anti-PD-1 therapy. Genomic characteristics common and unique to IL2 and/or anti-PD-1 therapy response are presented, with insight into rational combination strategies for these agents. Residual pretreatment formalin-fixed paraffin embedded tumor samples from n = 36 patients with HD-IL2 mRCC underwent RNA-sequencing and corresponding clinical data were collected. A de novo 40-gene nearest centroid IL2 treatment response classifier and individual gene and/or immune marker signature differences were correlated to clinical response and placed into context with a separate dataset of n = 35 patients with anti-PD-1 mRCC. Immune signatures and genes, comprising suppressor and effector cells, were increased in patients with HD-IL2 clinical benefit. The 40-gene response classifier was also highly enriched for immune genes. While several effector immune signatures and genes were common between IL2 and anti-PD-1 treated patients, multiple inflammatory and/or immunosuppressive genes, previously reported to predict poor response to anti-PD-L1 immunotherapy, were only increased in IL2-responsive tumors. These findings suggest that common and distinct immune-related response markers for IL2 and anti-PD-1 therapy may help guide their use, either alone or in combination.

Significance

Next-generation IL2 agents, designed for improved tolerability over traditional HD-IL2 (aldesleukin), are in clinical development. Retrospective molecular tumor profiling of patients treated with HD-IL2 or anti-PD-1 therapy provides insights into genomic characteristics of therapy response. This study revealed common and distinct immune-related predictive response markers for IL2 and anti-PD-1 therapy which may play a role in therapy guidance, and rational combination strategies for these agents.

Methods for Establishing a Renal Cell Carcinoma Tumor Spheroid Model With Immune Infiltration for Immunotherapeutic Studies

Tumor spheroids play an increasingly important role in cancer research. Their ability to recapitulate crucial features of tumor biology that are lost in the classically used 2D models along with their relative simplicity and handiness have made them the most studied 3D tumor model. Their application as a theranostic tool or as a means to study tumor-host interaction is now well-established in various cancers. However, their use in the field of Renal Cell Carcinoma (RCC) remains very limited. The aim of this work is to present methods to implement a basic RCC spheroid model. These methods cover the steps from RCC tumor dissociation to spheroid infiltration by immune cells. We present a protocol for RCC dissociation using Liberase TM and introduce a culture medium containing Epithelial Growth Factor and Hydrocortisone allowing for faster growth of RCC primary cells. We show that the liquid overlay technique allows for the formation of spheroids from cell lines and from primary cultures. We present a method using morphological criteria to select a homogeneous spheroid population based on a Fiji macro. We then show that spheroids can be infiltrated by PBMCs after activation with OKT3 or IL-15. Finally, we provide an example of application by implementing an immune spheroid killing assay allowing observing increased spheroid destruction after treatment with PD-1 inhibitors. Thus the straightforward methods presented here allow for efficient spheroid formation for a simple RCC 3D model that can be standardized and infused with immune cells to study immunotherapies.

Preliminary study on the role of the C5orf46 gene in renal cancer

•

The C5orf46 gene was first studied in tumors.

•

C5orf46 gene is involved in tumor immunity.

•

C5orf46 gene as a possible target for immunotherapy in renal cancer

Background

C5orf46 has been found to have antibacterial and anti-inflammatory effects via sequencing and microarray technologies, but its effects on cancer are unclear.

Methods

C5orf46 expression in renal cancer patients and cell lines was measured by quantitative polymerase chain reaction (qPCR). RNA sequencing data and clinicopathological information from renal cancer patients extracted from The Tumor Genome Atlas (TCGA) were analyzed to evaluate the prognostic value of C5orf46. The role of C5orf46 in vitro was verified by migration, proliferation and apoptosis experiments in renal cancer cell lines. Furthermore, the transcriptome of renal cancer cell lines with C5orf46 knocked down was sequenced to analyze potential signaling network pathways. Finally, the possible mechanisms of C5orf46 involvement in renal cancer development were analyzed by evaluating the immune microenvironment, mutation status and methylation levels.

Results

C5orf46 was highly expressed in renal cancer and was an independent prognostic factor. In vitro cell experiments showed that inhibition of C5orf46 expression could reduce renal cancer cell proliferation and migration and increase apoptosis. Transcriptomic sequencing after knockdown of C5orf46 in renal cancer cells revealed that it is involved in the malignant phenotype and immune microenvironment regulation of renal cancer. Finally, public databases suggest that C5orf46-related immune cell infiltration, mutational potential, and low methylation levels may contribute to poor prognosis in renal cancer.

Conclusion

These findings suggest that C5orf46 is associated with renal cancer progression and could be a potential target for improving renal cancer prognosis.

Current State of Cell Therapies for Genitourinary Malignancies

ABSTRACT

Genitourinary (GU) cancers have greatly benefited from immunotherapy treatments, such as immune checkpoint inhibitors. However, the durable clinical response rate for these agents remains relatively low, calling for more innovative immunotherapy approaches. Adoptive cell therapy has shown a significant advancement in the treatment of cancer in recent years and represents a great potential for the treatment of GU cancers. This review summarizes the current advancements in cellular therapy strategies for the treatment of renal cell carcinoma, bladder cancer, and prostate and penile cancers. Further, current and past clinical trials of adoptive cell therapy in GU tumors are reviewed. Finally, a perspective on the future of cell therapy in GU tumors is discussed.

Comprehensive analysis of lower mitochondrial complex I expression is associated with cell metastasis of clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is characterized by high metastasis potential. It is of great importance to explore the mechanisms underlying ccRCC metastasis and to enable development of potent therapeutics. The mitochondrial complex I (CI) had been considered to play an important role in the development of cancers, but less known in ccRCC.

Methods

We utilized available public databases of ccRCC, including single-cell RNA sequencing (scRNA-seq) data GSE73121 and The Cancer Genome Atlas-kidney renal clear cell carcinoma (TCGA-KIRC). Principal component analysis (PCA) and t-Distributed Stochastic Neighbor Embedding (tSNE) analysis were evaluated the heterogeneity of metastatic renal cell carcinoma (mRCC) and primary renal cell carcinoma (pRCC). Protein-protein interaction (PPI) network identified critical gene. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) performed to explore the potential biologic pathways.

Results

Our study revealed a significant gene expression heterogeneity between pRCC and mRCC. A PPI network based on differentially expressed genes (DEGs) identified electron transport chain (ETC), especially mitochondrial CI, as the key network hub. Further analysis revealed that the role of mitochondrial CI is associated with tumor metastasis and immune responds of ccRCC. Although CI had low frequency mutations in ccRCC, CI expression is associated with the high frequency mutated genes. A prognosis model included 7 CI genes, and these had a significant effect on overall survival (OS). The area under the curve at 1, 3, and 5 years was 0.717, 0.685, and 0.728, respectively. Transcription factor analysis predicted that PPARG possibly is a potential transcription activator of CI genes in ccRCC.

Conclusions

Overall, we found that CI expression is associated with ccRCC progress. CI and PPARG may be potential biomarkers for metastatic ccRCC.

The genomic landscape of pediatric renal cell carcinomas

Pediatric renal cell carcinomas (RCC) differ from their adult counterparts not only in histologic subtypes but also in clinical characteristics and outcome. However, the underlying biology is still largely unclear. For this reason, we performed whole-exome and transcriptome sequencing analyses on a cohort of 25 pediatric RCC patients with various histologic subtypes, including 10 MiT family translocation (MiT) and 10 papillary RCCs. In this cohort of pediatric RCC, we find only limited genomic overlap with adult RCC, even within the same histologic subtype. Recurrent somatic mutations in genes not previously reported in RCC were detected, such as in CCDC168, PLEKHA1, VWF, and MAP3K9. Our papillary pediatric RCCs, which represent the largest cohort to date with comprehensive molecular profiling in this age group, appeared as a distinct genomic subtype differing in terms of gene mutations and gene expression patterns not only from MiT-RCC but also from their adult counterparts.

•

WES and RNA-seq of 25 pediatric RCCs with various histologic subtypes

•

Detected only limited genomic overlap with adult RCC

•

Revealed recurrent somatic mutations in genes not previously reported in RCC

•

Discovery of a CRK-PITPNA fusion gene in a pediatric papillary RCC

Adoptive T-cell Immunotherapy: Perfecting Self-Defenses

As an important part of the immune system, T lymphocytes exhibit undoubtedly an important role in targeting and eradicating cancer. However, despite these characteristics, their natural antitumor response may be insufficient. Numerous clinical trials in terminally ill cancer patients testing the design of novel and efficient immunotherapeutic approaches based on the adoptive transfer of autologous tumor-specific T lymphocytes have shown encouraging results. Moreover, this also led to the approval of engineered T-cell therapies in patients. Herein, we will expand on the development and the use of such strategies using tumor-infiltrating lymphocytes or genetically engineered T-cells. We will also comment on the requirements and potential hurdles encountered when elaborating and implementing such treatments as well as the exciting prospects for this kind of emerging personalized medicine therapy.

Identification of a Six-Gene Prognostic Signature Characterized by Tumor Microenvironment Immune Profiles in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is widely acknowledged to be extremely sensitive to immunotherapy, emphasizing the tremendous impacts on which the tumor microenvironment (TME) has shown. However, the molecular subgroups characterized by the TME features scarcely serve as the risk stratification guides in clinical practice for survival outcomes and immunotherapy response prediction. This study generated fresh insights into a novel TME-related prognostic signature derived from The Cancer Genome Atlas database using integrated bioinformatics analyses. Subsequently, Kaplan–Meier survival analysis, receiver operating characteristic analysis, and univariate and multivariate Cox regression analysis were performed to evaluate and validate the efficacy and the accuracy of the signature in ccRCC prognosis. Furthermore, we discovered that the risk score presented an increased likelihood of correlation with miscellaneous clinicopathological characteristics, natural killer cell-mediated cytotoxicity, immune cell infiltration levels, and immune checkpoint expression. These findings highlighted the notion that the six-gene signature characterized by the TME features may have implications on the risk stratification for personalized and precise immunotherapeutic management.

Molecular Mechanisms of Resistance to Immunotherapy and Antiangiogenic Treatments in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common histological subtype arising from renal cell carcinomas. This tumor is characterized by a predominant angiogenic and immunogenic microenvironment that interplay with stromal, immune cells, and tumoral cells. Despite the obscure prognosis traditionally related to this entity, strategies including angiogenesis inhibition with tyrosine kinase inhibitors (TKIs), as well as the enhancement of the immune system with the inhibition of immune checkpoint proteins, such as PD-1/PDL-1 and CTLA-4, have revolutionized the treatment landscape. This approach has achieved a substantial improvement in life expectancy and quality of life from patients with advanced ccRCC. Unfortunately, not all patients benefit from this success as most patients will finally progress to these therapies and, even worse, approximately 5 to 30% of patients will primarily progress. In the last few years, preclinical and clinical research have been conducted to decode the biological basis underlying the resistance mechanisms regarding angiogenic and immune-based therapy. In this review, we summarize the insights of these molecular alterations to understand the resistance pathways related to the treatment with TKI and immune checkpoint inhibitors (ICIs). Moreover, we include additional information on novel approaches that are currently under research to overcome these resistance alterations in preclinical studies and early phase clinical trials.

Establishment of a prognosis Prediction Model Based on Pyroptosis-Related Signatures Associated With the Immune Microenvironment and Molecular Heterogeneity in Clear Cell Renal Cell Carcinoma

Background

Pyroptosis is essential for tumorigenesis and progression of neoplasm. However, the heterogeneity of pyroptosis and its relationship with the tumor microenvironment (TME) in clear cell renal cell carcinoma (ccRCC) remain unclear. The purpose of the present study was to identify pyroptosis-related subtypes and construct a prognosis prediction model based on pyroptosis signatures.

Methods

First, heterogenous pyroptosis subgroups were explored based on 33 pyroptosis-related genes and ccRCC samples from TCGA, and the model established by LASSO regression was verified by the ICGC database. Then, the clinical significance, functional status, immune infiltration, cell–cell communication, genomic alteration, and drug sensitivity of different subgroups were further analyzed. Finally, the LASSO-Cox algorithm was applied to narrow down the candidate genes to develop a robust and concise prognostic model.

Results

Two heterogenous pyroptosis subgroups were identified: pyroptosis-low immunity-low C1 subtype and pyroptosis-high immunity-high C2 subtype. Compared with C1, C2 was associated with a higher clinical stage or grade and a worse prognosis. More immune cell infiltration was observed in C2 than that in C1, while the response rate in the C2 subgroup was lower than that in the C1 subgroup. Pyroptosis-related genes were mainly expressed in myeloid cells, and T cells and epithelial cells might influence other cell clusters via the pyroptosis-related pathway. In addition, C1 was characterized by MTOR and ATM mutation, while the characteristics of C2 were alterations in SPEN and ROS1 mutation. Finally, a robust and promising pyroptosis-related prediction model for ccRCC was constructed and validated.

Conclusion

Two heterogeneous pyroptosis subtypes were identified and compared in multiple omics levels, and five pyroptosis-related signatures were applied to establish a prognosis prediction model. Our findings may help better understand the role of pyroptosis in ccRCC progression and provide a new perspective in the management of ccRCC patients.

Development of an Individualized Immune Prognostic Signature for Clear Cell Renal Cell Carcinoma through the Identification of Differential Immune Genes

Increasing evidence has shown that tumor microenvironments are an important feature in clear cell renal cell carcinoma (ccRCC) carcinogenesis and therapeutic efficacy. In this study, two subtypes of ccRCC, high- and low-immune groups, were identified based on the immune gene datasets, of which the differential immune genes were identified accordingly. Furthermore, we constructed a risk prognosis model using five immune genes, specifically, AQP9, KIAA1429, HAMP, CCL13, and CCL21. This model was highly predictive of ccRCC clinical characteristics and showed potential for use in immunotherapy. Furthermore, the five identified genes were highly correlated with the abundance of B cells, CD4 T cells, CD8 T cells, macrophages, neutrophils, and dendritic cells in the tumor microenvironments. Among them, AQP9, KIAA1429, and HAMP exhibited significant prognostic potential. These findings indicate that monitoring and operating tumor microenvironments are of great significance for ccRCC prognosis and precise immunotherapy.

Cancer-associated fibroblasts in renal cell carcinoma: implication in prognosis and resistance to anti-angiogenic therapy

OBJECTIVES

To investigate the role of cancer-associated fibroblasts (CAFs) in clear cell renal cell carcinoma (ccRCC) with respect to tumour aggressiveness, metastasis development, and resistance to anti-angiogenic therapy (vascular endothelial growth factor receptor-tyrosine kinase inhibitors [VEGFR-TKI]).

PATIENTS AND METHODS

Our study involved tissue samples from three distinct and independent cohorts of patients with ccRCC. The presence of CAFs and tumour lymphangiogenesis was investigated, respectively, by transcriptional signatures and then correlated with tumour development and prognosis. The effect of these CAFs on tumour cell migration and VEGFR-TKI resistance was analysed on co-cultures of ccRCC cells with CAFs.

RESULTS

Results from our cohorts and from in silico investigations showed that VEGFR-TKI significantly increase the number of CAFs in tumours. In the same populations of patients with ccRCC, the proportion of intra-tumoral CAFs correlated to shorter disease-free and overall survival. The presence of CAFs was also correlated with lymphangiogenesis and lymph node metastasis. CAFs increased the migration and decreased the VEGFR-TKI-dependent cytotoxic effect of tumour cells.

CONCLUSIONS

Our results show that VEGFR-TKI promote the development of CAFs, and CAFs favour tumour aggressiveness, metastatic dissemination, and resistance to treatment in ccRCC. CAFs could represent a new therapeutic target to fight resistance to treatment of ccRCC. Targeting CAF and immunotherapies combination are emerging as efficient treatments in many types of solid tumours. Our results highlight their relevance in ccRCC.

Identification and biological characteristics of clear cell renal cell carcinoma associated urine-derived stem cells

Urine-derived stem cells (USC) are isolated from voided urine and have demonstrated potential for use in tissue engineering and regenerative medicine therapies. Clear cell renal cell carcinoma (ccRCC) is a common urological malignancy that originates in the kidney. Since USC also originate in the kidney, the objective of this study was to investigate any biological differences between USC isolated from healthy patients and those isolated from ccRCC patients (rc-USC). We found that USC can be isolated from the voided urine of ccRCC patients (rc-USC) and have a morphology and function similar to those isolated from healthy donors. However, the rc-USC showed greater proliferation and invasion capacity than USC, and possessed some features of cancer cells; but the rc-UC were not able to form xenografts when implanted in vivo. We further performed RNA sequencing of rc-USC and USC and found several differentially expressed lncRNAs and mRNAs; however subsequent GO and KEGG enrichment analysis showed few pathway differences between these cells. Bioinformatic analyses and RT-PCR showed the expression of several known ccRCC-related genes in rc-USC expressed, as compared to USC derived from healthy donors. This study demonstrates that rc-USC displayed several cellular and genetic features of ccRCC cells, which suggests that this population of cells could provide a non-invasive approach for for the diagnosis, predication, disease modeling and therapeutic strategies targeting ccRCC.

VISTA: A Mediator of Quiescence and a Promising Target in Cancer Immunotherapy

V-domain Ig suppressor of T cell activation (VISTA) is a B7 family member that maintains T cell and myeloid quiescence and is a promising target for combination cancer immunotherapy. During inflammatory challenges, VISTA activity reprograms macrophages towards reduced production of proinflammatory cytokines and increased production of interleukin (IL)-10 and other anti-inflammatory mediators. The interaction of VISTA with its ligands is regulated by pH, and the acidic pH ~6.0 in the tumor microenvironment (TME) facilitates VISTA binding to P-selectin glycoprotein ligand 1 (PSGL-1). Targeting intratumoral pH might be a way to reduce the immunoinhibitory activity of the VISTA pathway and enhance antitumor immune responses. We review differences among VISTA therapeutics under development as candidate immunotherapies, focusing on VISTA binding partners and the unique structural features of this interaction.

Targeting Strategies for Renal Cancer Stem Cell Therapy

Renal cell carcinoma (RCC) is an intractable genitourinary malignancy that accounts for approximately 4% of adult malignancies. Currently, there is no approved targeted therapy for RCC that has yielded durable remissions, and they remain palliative in intent. Emerging evidence has indicated that renal tumorigenesis and RCC treatment-resistance may originate from renal cancer stem cells (CSCs) with tumor-initiating capacity (CSC hypothesis). A better understanding of the mechanism underlying renal CSCs will help to dissect RCC heterogeneity and drug treatment efficiency, to promote more personalized and targeted therapies. In this review, we summarized the stem cell characteristics of renal CSCs. We outlined the targeting strategies and challenges associated with developing therapies that target renal CSCs angiogenesis, immunosuppression, signaling pathways, surface biomarkers, microRNAs and nanomedicine. In conclusion, CSCs are an important role in renal carcinogenesis and represent a valid target for treatment of RCC patients.

Identification of Key Genes of Prognostic Value in Clear Cell Renal Cell Carcinoma Microenvironment and a Risk Score Prognostic Model

Objective

We aimed at identifying the key genes of prognostic value in clear cell renal cell carcinoma (ccRCC) microenvironment and construct a risk score prognostic model.

Materials and Methods

Immune and stromal scores were calculated using the ESTIMATE algorithm. A total of 539 ccRCC cases were divided into high- and low-score groups. The differentially expressed genes in immune and stromal cells for the prognosis of ccRCC were screened. The relationship between survival outcome and gene expression was evaluated using univariate and multivariate Cox proportional hazard regression analyses. A risk score prognostic model was constructed based on the immune/stromal scores.

Results

The median survival time of the low immune score group was longer than that of the high immune score group (p = 0.044). Ten tumor microenvironment-related genes were selected by screening, and a predictive model was established, based on which patients were divided into high- and low-risk groups with markedly different overall survival (p < 0.0001). Multivariate Cox analyses showed that the risk score prognostic model was independently associated with overall survival, with a hazard ratio of 1.0437 (confidence interval: 1.0237-1.0641, p < 0.0001).

Conclusions

Low immune scores were associated with extended survival time compared to high immune scores. The novel risk predictive model based on tumor microenvironment-related genes may be an independent prognostic biomarker in ccRCC.

Synergies of Antiangiogenic Therapy and Immune Checkpoint Blockade in Renal Cell Carcinoma: From Theoretical Background to Clinical Reality

The hallmarks of renal cell carcinoma (RCC) are angiogenesis and immunogenic tumor microenvironment. Over the past decades, treatment options for metastatic RCC (mRCC) have been expanding, from the inhibition of vessel formation via antiangiogenic agents (AAs) to the stimulation of immune system by immune checkpoint inhibitors (ICIs). Since 2005, the introduction of antiangiogenic agents targeting vascular endothelial growth factor (VEGF), its receptors (VEGFRs), and mammalian target of rapamycin (mTOR) pathway have experienced moderate success in the therapeutics of mRCC, but patient outcomes remain suboptimal. Recently, the development of ICIs targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and the programmed death-1/programmed death ligand 1 (PD-1/PD-L1) pathways has dramatically changed the treatment landscape of mRCC. Expressly, the combination of ipilimumab and nivolumab has been confirmed to improve clinical outcomes and approved as a standard care for intermediate- or poor-risk mRCC patients. Nevertheless, innate or adaptive drug resistance is observed within both treatment approaches, limiting overall clinical benefit. This phenomenon will underscore the urgent need for new combinational therapy strategies with different mechanisms of action, which can improve efficacy in an extended patient population without severe toxic effects. In 2019, as the results of two critical phase III trials came to light, FDA approved axitinib plus avelumab, or pembrolizumab as first-line standard management for mRCC, which cements the combination of AAs plus ICIs and advances the mRCC treatment field. This review summarizes current evidence on the interplay and synergies between AAs and immunomodulating drugs in mRCC, focusing on the theoretical background and the status of current clinical development.

Resistance to cancer immunotherapy in metastatic renal cell carcinoma

The prognosis of metastatic clear cell renal cell carcinoma (mccRCC) has changed dramatically over the years with the emergence of immune checkpoint inhibitors (ICI) used alone, or in combination with another ICI, or with vascular endothelial growth factor receptor tyrosine kinase inhibitor. Although major response rates have been observed with ICI, many patients do not respond, reflecting primary resistance, and durable responses remain exceptional, reflecting secondary resistance. Factors contributing to primary and acquired resistance are manifold, including patient-intrinsic factors, tumor cell-intrinsic factors and factors associated with the tumoral microenvironment (TME). While some mechanisms of resistance are common to several tumor types, others are specific to mccRCC. Predictive biomarkers and alternative strategies are needed to overcome this resistance. This review provides an overview of the major ICI resistance mechanisms, highlights the potential of the TME to induce resistance to ICI, and discusses the predictive biomarkers available to guide therapeutic choice.

The pattern and prognostic relevance of immune activity scores and tumor-infiltrating immune cells in metastatic clear cell renal cell carcinoma: Evidence from multiple datasets

PURPOSE

To investigate the immune activity scores (IAS) and tumor-infiltrating immune cells (TIIC) in metastatic clear cell renal cell carcinoma (mccRCC) patients and to explore their patterns and potential prognostic values.

METHODS

The gene expression profiles and clinical information of ccRCC patients from multiple Gene Expression Omnibus (GEO) datasets and TCGA were used as study cohorts. Overall, 3 sets of 69 variables associated with tumor-immune interactions were collected from several tumor immunophenotype analysis websites. Least absolute shrinkage and selection operator (LASSO) and area under receiver operating characteristic (AUC) analyses were performed to establish and evaluate the predictive models.

RESULTS

Several TIIC and IAS variables are significantly different between patients and between different sites within the same patient. The AUC of the multivariable logistic models based on IAS and the two TIIC groups is 0.705 (95%CI 0.643-0.766), 0.719 (95%CI 0.650-0.788), and 0.685 (95%CI 0.623-0.747), respectively. The AUC of the LASSO model is 0.715 (95%CI 0.652-0.777). Certain subtypes identified by the consensus clustering method show a favorable OS (log-rank, p < 0.01) in both nonmetastatic and metastatic ccRCC patients.

CONCLUSION

IAS and TIIC could vary between patients and different sites within the same patient, and distinct patterns of these variables could correlate with clinical features. Heterogeneity might exist in the biological process of metastasis. LASSO logistic regression reveals that the infiltration of two TIICs would be a predictor of metastatic ccRCC. Last, certain subtypes may have a better prognosis in both ccRCC and mccRCC patients.