The Metabolic Basis of Kidney Cancer

Obesity-Dependent Adipokine Chemerin Suppresses Fatty Acid Oxidation to Confer Ferroptosis Resistance

Clear cell renal cell carcinoma (ccRCC) is characterized by accumulation of neutral lipids and adipogenic transdifferentiation. We assessed adipokine expression in ccRCC and found that tumor tissues and patient plasma exhibit obesity-dependent elevations of the adipokine chemerin. Attenuation of chemerin by several approaches led to significant reduction in lipid deposition and impairment of tumor cell growth in vitro and in vivo. A multi-omics approach revealed that chemerin suppresses fatty acid oxidation, preventing ferroptosis, and maintains fatty acid levels that activate hypoxia-inducible factor 2α expression. The lipid coenzyme Q and mitochondrial complex IV, whose biogeneses are lipid-dependent, were found to be decreased after chemerin inhibition, contributing to lipid reactive oxygen species production. Monoclonal antibody targeting chemerin led to reduced lipid storage and diminished tumor growth, demonstrating translational potential of chemerin inhibition. Collectively, the results suggest that obesity and tumor cells contribute to ccRCC through the expression of chemerin, which is indispensable in ccRCC biology. SIGNIFICANCE: Identification of a hypoxia-inducible factor-dependent adipokine that prevents fatty acid oxidation and causes escape from ferroptosis highlights a critical metabolic dependency unique in the clear cell subtype of kidney cancer. Targeting lipid metabolism via inhibition of a soluble factor is a promising pharmacologic approach to expand therapeutic strategies for patients with ccRCC.See related commentary by Reznik et al., p. 1879.This article is highlighted in the In This Issue feature, p. 1861.

A Web of Science-based scientometric analysis about mammalian target of rapamycin signaling pathway in kidney disease from 1986 to 2020

Background

The mammalian target of rapamycin (mTOR) signaling pathway is vital for the regulation of cell metabolism, growth and proliferation in the kidney. This study aims to show current research focuses and predict future trends about mTOR pathway in kidney disease by the methods of scientometric analysis.

Methods

We referred to publications from the Web of Science^TM Core Collection (WoSCC) Database. Carrot2, VOSviewer and CiteSpace programs were applied to evaluate the distribution and contribution of authors, institutes and countries/regions of extensive bibliographic metadata, show current research focuses and predict future trends in kidney disease's area.

Results

Until July 10, 2020, there are 2,585 manuscripts about mTOR signaling pathway in kidney disease in total and every manuscript is cited 27.39 times on average. The big name of course is the United States. Research hot spots include "diabetic nephropathy", "kidney transplantation", "autosomal dominant polycystic kidney disease", "tuberous sclerosis complex", "renal cell carcinoma" and "autophagy". Seven key clusters are detected, including "kidney transplantation", "autosomal dominant polycystic kidney disease", "renal transplantation", "renal cell carcinoma", "hamartin", "autophagy" and "tuberous sclerosis complex".

Conclusions

Diabetic nephropathy, kidney transplantation, autosomal dominant polycystic kidney disease, tuberous sclerosis complex, renal cell carcinoma and autophagy are future research hot spots by utilizing scientometric analysis. In the future, it is necessary to research these fields.

Precision Surgery and Kidney Cancer: Knowledge of Genetic Alterations Influences Surgical Management

Renal cell carcinoma is a term that represents multiple different disease processes, each driven by different genetic alterations, with distinct histology, and biological potential which necessitates divergent management strategies. This review discusses the genetic alterations seen in several forms of hereditary kidney cancer and how that knowledge can dictate when and how to intervene with a focus on the surgical management of these tumors.

Oncometabolite L-2-hydroxyglurate directly induces vasculogenic mimicry through PHLDB2 in renal cell carcinoma

Metabolism reprograming is a hallmark of cancer and plays an important role in tumor progression. The aberrant metabolism in renal cell carcinoma (RCC) leads to accumulation of the oncometabolite l‐2‐hydroxyglurate (L‐2HG). L‐2HG has been reported to inhibit the activity of some α‐ketoglutarate‐dependent dioxygenases such as TET enzymes, which mediate epigenetic alteration, including DNA and histone demethylation. However, the detailed functions of L‐2HG in renal cell carcinoma have not been investigated thoroughly. In our study, we found that L‐2HG was significantly elevated in tumor tissues compared to adjacent tissues. Furthermore, we demonstrated that L‐2HG promoted vasculogenic mimicry (VM) in renal cancer cell lines through reducing the expression of PHLDB2. A mechanism study revealed that activation of the ERK1/2 pathway was involved in L‐2HG‐induced VM formation. In conclusion, these findings highlighted the pathogenic link between L‐2HG and VM and suggested a novel therapeutic target for RCC.

What's new?

Metabolic reprograming, a hallmark of cancer, influences tumor progression. In the case of renal cell carcinoma (RCC) specifically, progression appears to be facilitated by the oncometabolite L‐2‐hydroxyglurate (L‐2HG), though underlying mechanisms remain enigmatic. Here, the authors investigated the ability of L‐2HG in RCC to promote vasculogenic mimicry (VM), in which aggressive cancer cells form vessel‐like networks that support tumor growth. Analyses of RCC patient tissues revealed elevated L‐2HG levels, wherein tumor cells with greater L‐2HG levels exhibited more VM structures. TCGA data and high‐throughput sequencing analyses further show that L‐2HG contributes to VM formation via reduction of PHLDB2 levels.

Mitochondrial DNA alterations underlie an irreversible shift to aerobic glycolysis in fumarate hydratase-deficient renal cancer

Understanding the mechanisms of the Warburg shift to aerobic glycolysis is critical to defining the metabolic basis of cancer. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an aggressive cancer characterized by biallelic inactivation of the gene encoding the Krebs cycle enzyme fumarate hydratase, an early shift to aerobic glycolysis, and rapid metastasis. We observed impairment of the mitochondrial respiratory chain in tumors from patients with HLRCC. Biochemical and transcriptomic analyses revealed that respiratory chain dysfunction in the tumors was due to loss of expression of mitochondrial DNA (mtDNA)-encoded subunits of respiratory chain complexes, caused by a marked decrease in mtDNA content and increased mtDNA mutations. We demonstrated that accumulation of fumarate in HLRCC tumors inactivated the core factors responsible for replication and proofreading of mtDNA, leading to loss of respiratory chain components, thereby promoting the shift to aerobic glycolysis and disease progression in this prototypic model of glucose-dependent human cancer.

YTHDF2 is a Potential Biomarker and Associated with Immune Infiltration in Kidney Renal Clear Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC or KIRC) has a high mortality rate globally. It is necessary to identify biomarkers and investigate the mechanisms those biomarkers are associated with, to improve the prognosis of patients with KIRC. N6-Methyladenosine (m6A) affects the fate of modified RNA molecules and is involved in tumor progression. Different webservers were used in our research to investigate the mRNA transcription and clinical significance of YTHDF2 in KIRC. Survival analysis revealed that patients with elevated YTHDF2 transcription had a slightly longer OS and DFS than those with low YTHDF2 expression. YTHDF2 expression was shown to be significantly associated with the abundance of immune cells such as B cells, CD8⁺ T cells, CD4⁺ T cells, macrophages, neutrophils, and dendritic cells. For a series of enrichment studies, we combined information on YTHDF2-binding molecules and expression-linked genes and identified the possible influence of "mRNA surveillance pathway," "RNA degradation," and "RNA transport" in the biology or pathogeny of KIRC. In addition, we identified multiple miRNA, kinase, and transcription factor targets of YTHDF2 in KIRC and constructed target networks. Overall, our findings show that YTHDF2 is a possible indicator of immune infiltration in the KIRC.

Bioinformatics Analysis of the Prognostic and Biological Significance of ZDHHC-Protein Acyltransferases in Kidney Renal Clear Cell Carcinoma

ZDHHC-protein acyltransferases (ZDHHCs) are a family of 23 signature Asp-His-His-Cys (DHHC) domain-containing enzymes that mediate palmitoylation by covalent attachment of the 16-carbon fatty acid palmitate to thiol groups of specific cysteine residues in substrate proteins. Emerging evidence has shown abnormal expression of ZDHHCs in a variety of disease states, including cancer. Kidney renal clear cell carcinoma (KIRC) is the eighth most common type of cancer, which accounts for the majority of malignant kidney tumors. However, there are currently no effective therapeutic targets or biomarkers for clinical treatment and prognosis in KIRC. In this study, we first analyzed the expression pattern of the 23 ZDHHCs in KIRC using TCGA and GEPIA database, and found that the expression of ZDHHC2, 3, 6, 14, 15, 21, and 23 was significantly down-regulated whereas the expression of ZDHHC9, 17, 18, 19 and 20 was significantly up-regulated in KIRC patient tissues vs. normal tissues. And the expression of ZDHHC2, 3, 6, 9, 14, 15, and 21 in tumors decreased with the increase of the pathological stage of KIRC patients. Notably, KIRC patients with decreased expression of ZDHHC3, 6, 9, 14, 15, 17, 20, 21, 23 and increased expression of ZDHHC19 were significantly associated with poor prognosis. Further, we found that there was a significant correlation between ZDHHC3, 6, 9, 14, 15, 17, 19, 20, 21, 23 expressions and immune cell infiltration. Besides, high mRNA expression was the most common type of gene alteration and there was a high correlation among the expression of ZDHHC6, 17, 20 and 21. Finally, function prediction indicated that the immune or metabolic disorders or the activation of oncogenic signaling pathways caused by abnormal expression of these ZDHHCs may be important mechanisms of tumor progression and poor prognosis in patients with KIRC. Our results may provide novel insight for identifying tumor markers or molecular targets for the treatment of KIRC.

Identification of Novel Glycolysis-Related Gene Signatures Associated With Prognosis of Patients With Clear Cell Renal Cell Carcinoma Based on TCGA

Objective

The purpose of the present study was to detect novel glycolysis-related gene signatures of prognostic values for patients with clear cell renal cell carcinoma (ccRCC).

Methods

Glycolysis-related gene sets were acquired from the Molecular Signatures Database (V7.0). Gene Set Enrichment Analysis (GSEA) software (4.0.3) was applied to analyze glycolysis-related gene sets. The Perl programming language (5.32.0) was used to extract glycolysis-related genes and clinical information of patients with ccRCC. The receiver operating characteristic curve (ROC) and Kaplan-Meier curve were drawn by the R programming language (3.6.3).

Results

The four glycolysis-related genes (B3GAT3, CENPA, AGL, and ALDH3A2) associated with prognosis were identified using Cox proportional regression analysis. A risk score staging system was established to predict the outcomes of patients with ccRCC. The patients with ccRCC were classified into the low-risk group and high-risk group.

Conclusions

We have successfully constructed a risk staging model for ccRCC. The model has a better performance in predicting the prognosis of patients, which may have positive reference value for the treatment and curative effect evaluation of ccRCC.

An Iron Metabolism-Related SLC22A17 for the Prognostic Value of Gastric Cancer

Purpose

Gastric cancer (GC) is a type of malignant cancer with a poor prognosis. The iron’s metabolism plays an important role in the process of GC. The aim of this study was to evaluate the effectiveness of SLC22A17, associated with iron metabolism, in predicting the prognosis of GC patients.

Materials and Methods

We analyzed genes related to iron metabolism of gastric cancer mRNA-seq data from TCGA database. We identified an iron metabolism-related SLC22A17 as an independent prognostic factor using univariate and multivariate Cox regression analysis.

Results

Further research showed that SLC22A17 was related with many pathways involved in the process of gastric cancer, and the expression was associated with diverse cancer-infiltrating immune cells. The expression of SLC22A17 was associated with T (Topography).

Conclusion

We validated that SLC22A17 associated with iron metabolism could serve as a prognostic biomarker for GC patients.

Genomic Fabric Remodeling in Metastatic Clear Cell Renal Cell Carcinoma (ccRCC): A New Paradigm and Proposal for a Personalized Gene Therapy Approach

Simple Summary

We applied the genomic fabric principles for personalized gene therapy to a case of clear cell renal cell carcinoma (ccRCC). Despite decades of research, the process of finding the molecular mechanisms responsible for the disease and, more importantly, the therapeutic solution is still a work in progress. We analyzed the transcriptomes of the chest wall metastasis, two distinct cancer nodules, and the cancer-free surrounding tissue in the surgically removed right kidney of a Fuhrman grade 3 metastatic ccRCC patient. The studies revealed that even histopathologically equally classified cancer nodules from the same kidney have different transcriptomic topologies, requiring tailored therapeutic solutions not only for each patient but even for each cancer nodule. We identified death-associated protein kinase 3 (DAPK3); transcription activation suppressor (TASOR); family with sequence similarity 27, member C, long non-coding RNA (FAM27C); and UDP-N-acetylglucosaminyltransferase subunit (ALG13) as the gene master regulators of the four profiled regions and proposed molecular mechanisms by which expression manipulation of TASOR and ALG13 may selectively destroy the cancer cells without affecting many of the normal cells.

Abstract

Published transcriptomic data from surgically removed metastatic clear cell renal cell carcinoma samples were analyzed from the genomic fabric paradigm (GFP) perspective to identify the best targets for gene therapy. GFP considers the transcriptome as a multi-dimensional mathematical object constrained by a dynamic set of expression controls and correlations among genes. Every gene in the chest wall metastasis, two distinct cancer nodules, and the surrounding normal tissue of the right kidney was characterized by three independent measures: average expression level, relative expression variation, and expression correlation with each other gene. The analyses determined the cancer-induced regulation, control, and remodeling of the chemokine and vascular endothelial growth factor (VEGF) signaling, apoptosis, basal transcription factors, cell cycle, oxidative phosphorylation, renal cell carcinoma, and RNA polymerase pathways. Interestingly, the three cancer regions exhibited different transcriptomic organization, suggesting that the gene therapy should not be personalized only for every patient but also for each major cancer nodule. The gene hierarchy was established on the basis of gene commanding height, and the gene master regulators DAPK3,TASOR, FAM27C and ALG13 were identified in each profiled region. We delineated the molecular mechanisms by which TASOR overexpression and ALG13 silencing would selectively affect the cancer cells with little consequences for the normal cells.

Endocytosis-Mediated Replenishment of Amino Acids Favors Cancer Cell Proliferation and Survival in Chromophobe Renal Cell Carcinoma

Chromophobe renal cell carcinoma (chRCC) accounts for approximately 5% of all renal cancers and around 30% of chRCC cases have mutations in TP53. chRCC is poorly supported by microvessels and has markably lower glucose uptake than clear cell RCC and papillary RCC. Currently, the metabolic status and mechanisms by which this tumor adapts to nutrient-poor microenvironments remain to be investigated. In this study, we performed proteome and metabolome profiling of chRCC tumors and adjacent kidney tissues and identified major metabolic alterations in chRCC tumors, including the classical Warburg effect, the downregulation of gluconeogenesis and amino acid metabolism, and the upregulation of protein degradation and endocytosis. chRCC cells depended on extracellular macromolecules as an amino acid source by activating endocytosis to sustain cell proliferation and survival. Inhibition of the phospholipase C gamma 2 (PLCG2)/inositol 1,4,5-trisphosphate (IP3)/Ca²⁺/protein kinase C (PKC) pathway significantly impaired the activation of endocytosis for amino acid uptakes into chRCC cells. In chRCC, whole-exome sequencing revealed that TP53 mutations were not related to expression of PLCG2 and activation of endocytosis. Our study provides novel perspectives on metabolic rewiring in chRCC and identifies the PLCG2/IP3/Ca²⁺/PKC axis as a potential therapeutic target in patients with chRCC. SIGNIFICANCE: This study reveals macropinocytosis as an important process utilized by chRCC to gain extracellular nutrients in a p53-independent manner.

A Three-microRNA Panel in Serum: Serving as a Potential Diagnostic Biomarker for Renal Cell Carcinoma

PURPOSE

Renal cell carcinoma (RCC) accounts for about 120,000 death each year. Although surgery is a routine treatment, RCC could be fatal if not diagnosed at an early stage. This study aims to search for suitable serum biomarkers and construct a miRNA panel with high diagnostic sensitivity or specificity.

METHODS

Totally 146 RCC patients and 150 normal control were involved in this three-stage study. Serum expression levels of 30 miRNAs selected from literature were tested by reverse transcription quantitative PCR (RT-qPCR) in the screening stage, the testing stage, and the validation stage. The diagnostic efficiency of miRNAs was evaluated by receiver operating characteristic (ROC) curve and area under curve (AUC) analysis. A panel with the highest diagnostic efficiency was constructed by backward stepwise logistic regression analysis. Additionally, bioinformatics analysis was used to investigate potential biological functions and mechanisms of candidate miRNAs.

RESULTS

MiR-224-5p, miR-34b-3p, miR-129-2-3p and miR-182-5p with low to moderate diagnostic ability (AUC = 0.692, 0.778, 0.687 and 0.745, respectively) were selected as candidate miRNAs after the three-stage study. The final diagnostic panel was consisted by miR-224-5p, miR-34b-3p and miR-182-5p with AUC = 0.855. No significance has been found between these four miRNAs and tumor location, Fuhrman Grade and AJCC clinical stages of RCC. Bioinformatic analysis suggested that the three-miRNAs panel may participate in tumorigenesis of RCC by targeting CORO1C.

CONCLUSIONS

The three-miRNA panel in serum could serve as a non-invasive diagnostic biomarker of RCC.

Evaluation of aminolevulinic acid-mediated protoporphyrin IX fluorescence and enhancement by ABCG2 inhibitors in renal cell carcinoma cells

Aminolevulinic acid (ALA) has been approved as an intraoperative molecular imaging probe for protoporphyrin IX (PpIX) fluorescence-guided resection of glioma. Here we explored its potential application for renal cell carcinoma (RCC) that is showing increased incidence in recent years. ALA-mediated PpIX in cell lysates (intracellular) and culture medium was measured in five human RCC cell lines (786-O, 769-P, A-704, Caki-1, Caki-2) and a non-tumor human kidney epithelial cell line HK-2 by spectrofluorometry and flow cytometry. The activity of PpIX bioconversion enzyme ferrochelatase (FECH) and PpIX efflux transporter ABCG2 was determined to correlate with the PpIX level. We found that ALA-PpIX fluorescence was highly variable among RCC cell lines and A-704 was the only RCC cell line exhibiting significantly higher intracellular PpIX than HK-2 cells. Neither the intracellular PpIX level nor the total amount of PpIX (including PpIX in cell lysates and the medium) had significant correlation with the activity of FECH or ABCG2. To enhance the intracellular PpIX, cells were treated with Ko143, a pharmacological inhibitor of ABCG2. Ko143 significantly increased the intracellular PpIX in cell lines with ABCG2 activity, but not in cell lines with little ABCG2 activity. In fact, there was a positive correlation between the ABCG2 activity and Ko143-induced PpIX enhancement across kidney cell lines. To identify clinically relevant ABCG2 inhibitors, small molecule inhibitors targeting various cell signaling pathways, some of which are known to inhibit ABCG2, were evaluated for the enhancement of ALA-PpIX in Caki-2 cells that had the highest ABCG2 activity in the RCC cell panel. Our screening led to the identification of several clinically available inhibitors that significantly increased the intracellular PpIX. Particularly, kinase inhibitor lapatinib exhibited the strongest enhancement effect. These clinical inhibitors can be used for the enhancement of ALA-PpIX fluorescence in tumors with elevated ABCG2 activity.

Mitochondrial Metabolism as a Target for Cancer Therapy

Recent evidence in humans and mice supports the notion that mitochondrial metabolism is active and necessary for tumor growth. Mitochondrial metabolism supports tumor anabolism by providing key metabolites for macromolecule synthesis and generating oncometabolites to maintain the cancer phenotype. Moreover, there are multiple clinical trials testing the efficacy of inhibiting mitochondrial metabolism as a new cancer therapeutic treatment. In this review, we discuss the rationale of using these anti-cancer agents in clinical trials and highlight how to effectively utilize them in different tumor contexts.

Combination drug regimens for metastatic clear cell renal cell carcinoma

Renal cell carcinomas (RCC) make up about 90% of kidney cancers, of which 80% are of the clear cell subtype. About 20% of patients are already metastatic at the time of diagnosis. Initial treatment is often cytoreductive nephrectomy, but systemic therapy is required for advanced RCC. Single agent targeted therapies are moderately toxic and only somewhat effective, leading to development of immunotherapies and combination therapies. This review identifies limitations of monotherapies for metastatic renal cell carcinoma, discusses recent advances in combination therapies, and highlights therapeutic options under development. The goal behind combining various modalities of systemic therapy is to potentiate a synergistic antitumor effect. However, combining targeted therapies may cause increased toxicity. The initial attempts to create therapeutic combinations based on inhibition of the vascular endothelial growth factor or mammalian target of rapamycin pathways were largely unsuccessful in achieving a profile of increased synergy without increased toxicity. To date, five combination therapies have been approved by the U.S. Food and Drug Administration, with the most recently approved therapies being a combination of checkpoint inhibition plus targeted therapy. Several other combination therapies are under development, including some in the phase 3 stage. The new wave of combination therapies for metastatic RCC has the potential to increase response rates and improve survival outcomes while maintaining tolerable side effect profiles.

Fumarate hydratase-deficient renal cell carcinoma cells respond to asparagine by activation of the unfolded protein response and stimulation of the hexosamine biosynthetic pathway

Background

The loss-of-function mutation of fumarate hydratase (FH) is a driver of hereditary leiomyomatosis and renal cell carcinoma (HLRCC). Fumarate accumulation results in activation of stress-related mechanisms leading to upregulation of cell survival-related genes. To better understand how cells compensate for the loss of FH in HLRCC, we determined the amino acid nutrient requirements of the FH-deficient UOK262 cell line (UOK262) and its FH-repleted control (UOK262WT).

Methods

We determined growth rates and survival of cell lines in response to amino acid depletion and supplementation. RNAseq was used to determine the transcription changes contingent on Asn and Gln supplementation, which was further followed with stable isotope resolved metabolomics (SIRM) using both [U- ¹³C,¹⁵N] Gln and Asn.

Results

We found that Asn increased the growth rate of both cell lines in vitro. Gln, but not Asn, increased oxygen consumption rates and glycolytic reserve of both cell lines. Although Asn was taken up by the cells, there was little evidence of Asn-derived label in cellular metabolites, indicating that Asn was not catabolized. However, Asn strongly stimulated Gln labeling of uracil and precursors, uridine phosphates and hexosamine metabolites in the UOK262 cells and to a much lesser extent in the UOK262WT cells, indicating an activation of the hexosamine biosynthetic pathway (HBP) by Asn. Asn in combination with Gln, but not Asn or Gln alone, stimulated expression of genes associated with the endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in UOK262 to a greater extent than in FH-restored cells. The changes in expression of these genes were confirmed by RT-PCR, and the stimulation of the UPR was confirmed orthogonally by demonstration of an increase in spliced XBP1 (sXBP1) in UOK262 cells under these conditions. Asn exposure also increased both the RNA and protein expression of the HBP regulator GFPT2, which is a transcriptional target of sXBP1.

Conclusions

Asn in the presence of Gln induces an ER stress response in FH-deficient UOK262 cells and stimulates increased synthesis of UDP-acetyl glycans indicative of HBP activity. These data demonstrate a novel effect of asparagine on cellular metabolism in FH-deficient cells that could be exploited therapeutically.

Application Areas of Traditional Molecular Genetic Methods and NGS in relation to Hereditary Urological Cancer Diagnosis

Next generation sequencing (NGS) is widely used for diagnosing hereditary cancer syndromes. Often, exome sequencing and extended gene panel approaches are the only means that can be used to detect a pathogenic germline mutation in the case of multiple primary tumors, early onset, a family history of cancer, or a lack of specific signs associated with a particular syndrome. Certain germline mutations of oncogenes and tumor suppressor genes that determine specific clinical phenotypes may occur in mutation hot spots. Diagnosis of such cases, which involve hereditary cancer, does not require NGS, but may be made using PCR and Sanger sequencing. Diagnostic criteria and professional community guidelines developed for hereditary cancers of particular organs should be followed when ordering molecular diagnostic tests for a patient. This review focuses on urological oncology associated with germline mutations. Clinical signs and genetic diagnostic laboratory tests for hereditary forms of renal cell cancer, prostate cancer, and bladder cancer are summarized. While exome sequencing, or, conversely, traditional molecular genetic methods are the procedure of choice in some cases, in most situations, sequencing of multigene panels that are specifically aimed at detecting germline mutations in early onset renal cancer, prostate cancer, and bladder cancer seems to be the basic solution for molecular genetic diagnosis of hereditary cancers.

Metabolism in tumor microenvironment: Implications for cancer immunotherapy

Tumor microenvironment is a special environment for tumor survival, which is characterized by hypoxia, acidity, nutrient deficiency, and immunosuppression. The environment consists of the vasculature, immune cells, extracellular matrix, and proteins or metabolic molecules. A large number of recent studies have shown that not only tumor cells but also the immune cells in the tumor microenvironment have undergone metabolic reprogramming, which is closely related to tumor drug resistance and malignant progression. Tumor immunotherapy based on T cells gives patients new hope, but faces the dilemma of low response rate. New strategies sensitizing cancer immunotherapy are urgently needed. Metabolic reprogramming can directly affect the biological activity of tumor cells and also regulate the differentiation and activation of immune cells. The authors aim to review the characteristics of tumor microenvironment, the metabolic changes of tumor‐associated immune cells, and the regulatory role of metabolic reprogramming in cancer immunotherapy.

Extracellular Vesicles Enriched in hsa-miR-301a-3p and hsa-miR-1293 Dynamics in Clear Cell Renal Cell Carcinoma Patients: Potential Biomarkers of Metastatic Disease

Clear cell renal cell carcinoma (ccRCC) is the most aggressive subtype of kidney cancer and up to 40% of patients submitted to surgery with a curative intent will relapse. Thus, the aim of this study was to analyze the applicability of an Extracellular vesicle (EV) derived miRNA profile as potential prognosis biomarkers in ccRCC patients. We analyzed a nine-miRNA profile in plasma EVs from 32 ccRCC patients with localized disease (before and after surgery) and in 37 patients with metastatic disease. We observed that the levels of EV-derived hsa-miR-25-3p, hsa-miR-126-5p, hsa-miR-200c-3p, and hsa-miR-301a-3p decreased after surgery, whereas hsa-miR-1293 EV-levels increased. Furthermore, metastatic patients presented higher levels of hsa-miR-301a-3p and lower levels of hsa-miR-1293 when compared to patients with localized disease after surgery. Functional enrichment analysis of the targets of the four miRNAs that decreased after surgery resulted in an enrichment of terms related to cell cycle, proliferation, and metabolism, suggesting that EV-miRNA enrichment in the presence of the tumor could represent an epigenetic mechanism to sustain tumor development. Taken together, these results suggest that EVs content varies depending on the presence or absence of the disease and that an increase of EV-derived hsa-miR-301a-3p, and decrease of EV-derived hsa-miR-1293, may be potential biomarkers of metastatic ccRCC.

The Role of Heat Shock Protein-90 in the Pathogenesis of Birt-Hogg-Dubé and Tuberous Sclerosis Complex Syndromes

Birt-Hogg-Dubé (BHD) and tuberous sclerosis (TS) syndromes share many clinical features. These two diseases display distinct histologic subtypes of renal tumors: chromophobe renal cell carcinoma and renal angiomyolipoma, respectively. Early work suggested a role for mTOR dysregulation in the pathogenesis of these two diseases, however their detailed molecular link remains elusive. Interestingly, a growing number of case reports describe renal angiomyolipoma in BHD patients, suggesting a common molecular origin. The BHD-associated proteins FNIP1/2 and the TS protein Tsc1 were recently identified as regulators of the molecular chaperone Hsp90. Dysregulation of Hsp90 activity has previously been reported to support tumorigenesis, providing a potential explanation for the overlapping phenotypic manifestations in these two hereditary syndromes.

Case of Hereditary Papillary Renal Cell Carcinoma Type I in a Patient With a Germline MET Mutation in Russia

Hereditary papillary renal carcinoma (HPRC) is a rare autosomal dominant disease characterized by the development of multiple papillary type I renal cell carcinomas. This hereditary kidney cancer form is caused by activating mutations in MET. Descriptions of patients with HPRC are scarce in the world literature, and no cases have been described in open sources in Russia. Here, we describe a 28-year-old female Russian patient with 7 and 10 primary papillary renal cell carcinomas in the left and right kidneys, respectively. The patient did not have a family history of any of the known hereditary cancer syndromes. A comprehensive medical examination was performed in 2016 including computed tomography and pathomorphological analysis. The observed tumors were resected in a two-step surgical treatment. In February 2019, no sign of disease progression was detected in follow-up medical examination. Molecular genetic analysis revealed the germline heterozygous missense variant in MET: c.3328G>A (p.V1110I; CM990852). We have discussed the biological effects of the detected mutation and the utility of DNA diagnostics for treating patients with HPRC.

The Role of Serine Peptidase Inhibitor Kazal Type 13 (SPINK13) as a Clinicopathological and Prognostic Biomarker in Patients with Clear Cell Renal Cell Carcinoma

Background

The serine peptidase inhibitor Kazal type 13 (SPINK13) gene has tumor suppressor activity, but its role in renal cell carcinoma (RCC) remains unknown. This study aimed to investigate mRNA expression of SPINK13 in clear cell renal cell carcinoma (CCRCC) in human tissue and to use bioinformatics data to investigate the role of SPINK13 expression as a clinicopathological and prognostic biomarker for patients with CCRCC.

Material/Methods

Patients with CCRCC (N=533) with available RNA sequence data from The Cancer Genome Atlas (TCGA)-CCRCC database were analyzed with patients who had a tissue diagnosis of CCRCC (N=305) at the Fudan University Shanghai Cancer Center (FUSCC). Differential transcriptional and proteome expression profiles were obtained from the ONCOMINE cancer microarray database, TCGA, and the Human Protein Atlas (HPA) database. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR) measured SPINK13 mRNA expression in 305 samples of CCRCC tissue from the FUSCC. The effects of clinicopathological parameters on progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier and log-rank test.

Results

Transcriptional and proteome expression of SPINK13 were significantly increased CCRCC tissue samples. Increased SPINK13 mRNA expression was significantly associated with reduced PFS and OS in 838 patients with CCRCC patients from the two independent cohorts, the FUSCC and the TCGA-CCRCC cohorts (p<0.01). Gene set enrichment analysis (GSEA) showed that SPINK13 expression was involved in complement, apical junction, epithelial-mesenchymal transition (EMT), glycolysis, hypoxia, and inflammation signaling pathways.

Conclusions

Increased expression of SPINK13 was associated with poor prognosis in patients with CCRCC.

CA8 promotes RCC proliferation and migration though its expression level is lower in tumor compared to adjacent normal tissue

Chemotherapy and radiotherapy are not as successful in the case of renal cell carcinoma (RCC) although some targeted drugs were approved for RCC therapy recently. Analysis of whole genomic data will lead to improvements in understanding RCC and identifying novel anticancer targets. Here, we found the differential mRNA expression and copy number variation (CNV) of Carbonic anhydrase-related protein VIII (CA8) gene in RCC through integrated bioinformatics analysis of TCGA database, which was confirmed in 5 cases of samples collected from RCC patients who underwent radical nephrectomy by analysis of CA8 mRNA and protein levels using RT-PCR immunohistochemical assay. However, we got a completely opposite result that CA8 promoted RCC progression, those are CA8 overexpression promoted the proliferative and migratory ability of Caki-1 and 769-P cells in vitro as determined with MTT and transwell assay, and CA8 overexpression could also promote Caki-1 xenograft growth in BALB/C‑nu/nu mice. On the contrary, CA8-knockdown reduced Caki-1 and 769-P cell proliferation and migration. Moreover, knockdown of CA8 decreased pAKT and MMP2 protein levels in Caki-1 cells while overexpressing CA8 increased pAKT and MMP2. In conclusion, we showed that CA8 promoted RCC cell proliferation and migration, but it was down-regulated in RCC, which requires an additional mechanism study.

Prognostic implications of Aquaporin 9 expression in clear cell renal cell carcinoma

Background

Growing evidence has demonstrated immune reactivity as a confirmed important carcinogenesis and therapy efficacy for clear cell renal cell carcinoma (ccRCC). Aquaporin 9 (AQP9) is involved in many immune-related signals; however, its role in ccRCC remains to be elucidated. This study investigated AQP9 expression in tumor tissues and defined the prognostic value in ccRCC patients.

Methods

A total of 913 ccRCC patients with available RNA-sequence data from the Cancer Genome Atlas (TCGA) database and Fudan University Shanghai Cancer Center (FUSCC) were consecutively recruited in analyses. Differential transcriptional and proteome expression profiles were obtained and validated using multiple datasets. A partial likelihood test from Cox regression analysis was developed to address the influence of independent factors on progression-free survival (PFS) and overall survival (OS). The Kaplan–Meier method and log-rank test were performed to assess survival. Receiver operating characteristic (ROC) curves were used to describe binary classifier value of AQP9 using area under the curve (AUC) score. Functional enrichment analyses and immune infiltration analysis were used to describe significantly involved hallmark pathways of hub genes.

Results

Significantly elevated transcriptional and proteomic AQP9 expressions were found in ccRCC samples. Increased AQP9 mRNA expression was significantly associated with advanced clinicopathological parameters and correlated with shorter PFS and OS in TCGA and FUSCC cohorts (p < 0.001). ROC curves suggested the significant diagnostic and prognostic ability of AQP9 (PFS, AUC = 0.823; OS, AUC = 0.828). Functional annotations indicated that AQP9 is involved in the most significant hallmarks including complement, coagulation, IL6/JAK–STAT3, inflammatory response and TNF-alpha signaling pathways.

Conclusion

Our study revealed that elevated AQP9 expression was significantly correlated with aggressive progression, poor survival and immune infiltrations in ccRCC patients, and we validated its prognostic value in a real-world cohort. These data suggest that AQP9 may act as an oncogene and a promising prognostic marker in ccRCC.

Prognostic value and immune infiltration of novel signatures in clear cell renal cell carcinoma microenvironment

Growing evidence has highlighted the immune response as an important feature of carcinogenesis and therapeutic efficacy in clear cell renal cell carcinoma (ccRCC). This study categorized ccRCC cases into high and low score groups based on their immune/stromal scores generated by the ESTIMATE algorithm, and identified an association between these scores and prognosis. Differentially expressed tumor environment (TME)-related genes extracted from common upregulated components in immune and stromal scores were described using functional annotations and protein–protein interaction (PPI) networks. Most PPIs were selected for further prognostic investigation. Many additional previously neglected signatures, including AGPAT9, AQP7, HMGCS2, KLF15, MLXIPL, PPARGC1A, exhibited significant prognostic potential. In addition, multivariate Cox analysis indicated that MIXIPL and PPARGC1A were the most significant prognostic signatures, and were closely related to immune infiltration in TCGA cohort. External prognostic validation of MIXIPL and PPARGC1A was undertaken in 380 ccRCC cases from a real-world cohort. These findings indicate the relevance of monitoring and manipulation of the microenvironment for ccRCC prognosis and precision immunotherapy.

Genome-wide mutation profiling and related risk signature for prognosis of papillary renal cell carcinoma

Background

The papillary renal cell carcinoma (pRCC) is a rare subtype of renal cell carcinoma with limited investigation. Our study aimed to explore a robust signature to predict the prognosis of pRCC from the perspective of mutation profiles.

Methods

In this study, we downloaded the simple nucleotide variation data of 288 pRCC samples from The Cancer Genome Atlas (TCGA) database. "GenVisR" package was utilized to visualize gene mutation profiles in pRCC. The PPI network was conducted based on the STRING database and the modification was performed via Cytoscape software (Version 3.7.1). Top 50 mutant genes were selected and Cox regression method was conducted to identify the hub prognostic mutant signature in pRCC using "survival" package. Mutation Related Signature (MRS) risk score was established by multivariate Cox regression method. Receiver Operating Characteristic (ROC) curve drawn by "timeROC" was conducted to assess the predictive accuracy of overall survival (OS) and Kaplan-Meier analysis was then performed. Relationships between mutants and expression levels were compared by Wilcox rank-sum test. Function enrichment pathway analysis for mutated genes was performed by "org.Hs.eg.db", "clusterProfiler", "ggplot2" and "enrichplot" packages. Gene Set Enrichment Analysis was exploited using the MRS as the phenotypes, which worked based on the JAVA platform. All statistical analyses were achieved by R software (version 3.5.2). P value <0.05 was considered to be significant.

Results

The mutation landscape in waterfall plot revealed that a list of 49 genes that were mutated in more than 10 samples, of which 6 genes (TTN, MUC16, KMT2C, MET, OBSCN, LRP2) were mutated in more than 20 samples. Besides, non-synonymous was the most frequent mutation effect, and missense mutation was one of the most common mutation types in mutated genes across 248 samples. The AUC of MRS model consisted of 17 prognostic mutant signatures was 0.907 in 3-year OS prediction. Moreover, pRCC patients with high level of MRS showed the worse survival outcomes compared with that in low-level MRS group (P=0). In addition, correlation analysis indicated that 6 mutated genes (BAP1, OBSCN, NF2, SETD2, PBRM1, DNAH1) were significantly associated with corresponding expression levels. Last, functional enriched pathway analysis showed that these mutant genes were involved in multiple cancer-related crosstalk, including PI3K-AKT signaling pathway, JAK-STAT signaling pathway, extracellular matrix (ECM)-receptor interaction or cell cycle.

Conclusions

In summary, our study was the first attempt to explore the mutation-related signature for predicting survival outcomes of pRCC based on the high-throughput data, which might provide valuable information for further uncovering the molecular pathogenesis in pRCC.