Geospatial characterization of immune cell distributions and dynamics across the microenvironment in clear cell renal cell carcinoma.

INTRODUCTION: In clear cell renal cell carcinoma (ccRCC), tumor-associated macrophage (TAM) induction of CD8+T cells into a terminally exhausted state has been implicated as a major mechanism of immunotherapy resistance, but a deeper biological understanding is necessary. METHODS: Primary ccRCC tumor samples were obtained from 97 patients between 2004 and 2018. Multiplex immunofluorescence using lymphoid and myeloid markers was performed in seven regions of interest per patient across three predefined zones, and geospatial analysis was performed using Ripley's K analysis, a methodology adapted from ecology. RESULTS: Clustering of CD163+M2 like TAMs into the stromal compartment at the tumor-stroma interface was associated with worse clinical stage (tumor/CD163+nK(75): stage I/II: 4.4 (IQR -0.5 to 5.1); stage III: 1.4 (IQR -0.3 to 3.5); stage IV: 0.6 (IQR -2.1 to 2.1); p=0.04 between stage I/II and stage IV), and worse overall survival (OS) and cancer-specific survival (CSS) (tumor/CD163+nK(75): median OS-hi=149 months, lo=86 months, false-discovery rate (FDR)-adj. Cox p<0.001; median CSS-hi=174 months, lo=85 months; FDR-adj. Cox p<0.001). An RNA-seq differential gene expression score was developed using this geospatial metric, and was externally validated in multiple independent cohorts of patients with ccRCC including: TCGA KIRC, and the IMmotion151, IMmotion150, and JAVELIN Renal 101 clinical trials. In addition, this CD163+ geospatial pattern was found to be associated with a higher TIM-3+ proportion of CD8+T cells, indicative of terminal exhaustion (tumor-core: 0.07 (IQR 0.04-0.14) vs 0.40 (IQR 0.15-0.66), p=0.05). CONCLUSIONS: Geospatial clustering of CD163+M2 like TAMs into the stromal compartment at the tumor-stromal interface was associated with poor clinical outcomes and CD8+T cell terminal exhaustion.

Spatiotemporal evolution of the clear cell renal cell carcinoma microenvironment links intra-tumoral heterogeneity to immune escape.

BACKGROUND: Intratumoral heterogeneity (ITH) is a hallmark of clear cell renal cell carcinoma (ccRCC) that reflects the trajectory of evolution and influences clinical prognosis. Here, we seek to elucidate how ITH and tumor evolution during immune checkpoint inhibitor (ICI) treatment can lead to therapy resistance. METHODS: Here, we completed a single-arm pilot study to examine the safety and feasibility of neoadjuvant nivolumab in patients with localized RCC. Primary endpoints were safety and feasibility of neoadjuvant nivolumab. Then, we spatiotemporally profiled the genomic and immunophenotypic characteristics of 29 ccRCC patients, including pre- and post-therapy samples from 17 ICI-treated patients. Deep multi-regional whole-exome and transcriptome sequencing were performed on 29 patients at different time points before and after ICI therapy. T cell repertoire was also monitored from tissue and peripheral blood collected from a subset of patients to study T cell clonal expansion during ICI therapy. RESULTS: Angiogenesis, lymphocytic infiltration, and myeloid infiltration varied significantly across regions of the same patient, potentially confounding their utility as biomarkers of ICI response. Elevated ITH associated with a constellation of both genomic features (HLA LOH, CDKN2A/B loss) and microenvironmental features, including elevated myeloid expression, reduced peripheral T cell receptor (TCR) diversity, and putative neoantigen depletion. Hypothesizing that ITH may itself play a role in shaping ICI response, we derived a transcriptomic signature associated with neoantigen depletion that strongly associated with response to ICI and targeted therapy treatment in several independent clinical trial cohorts. CONCLUSIONS: These results argue that genetic and immune heterogeneity jointly co-evolve and influence response to ICI in ccRCC. Our findings have implications for future biomarker development for ICI response across ccRCC and other solid tumors and highlight important features of tumor evolution under ICI treatment. TRIAL REGISTRATION: The study was registered on ClinicalTrial.gov (NCT02595918) on November 4, 2015.

TMEM27 expression and clinical characteristics and survival in clear cell renal cell carcinoma.

BACKGROUND: Transmembrane protein 27 (TMEM27/collectrin), a glycoprotein and homolog of angiotensin-converting enzyme 2 (ACE2), is a regulator of renal amino acid uptake in the proximal tubule and may have a protective role in hypertension. Two previous reports have shown that the absence of TMEM27 expression in clear cell renal cell carcinoma (ccRCC) correlates with poorer cancer-related survival. We report our findings of TMEM27 expression in ccRCC and clinical outcomes in an independent third cohort. MATERIAL AND METHODS: We conducted a retrospective analysis to identify all 321 cases of ccRCC diagnosed between 2010 and 2015 at the University of Rochester Medical Center. The intensity of TMEM27 immunostaining on tumor tissue was semi-quantitatively graded on a scale of 0, 0.5, 1, 1.5, 2, 2.5, and 3 by a single pathologist, and correlated with tumor characteristics and survival. RESULTS: There was evidence of metastasis at time of nephrectomy in 36 (11.2%) cases, and at the latest follow-up in 70 (21.8%) cases. As of Spring 2021, 82 (25.5%) had died. TMEM27 staining intensity correlated inversely with various tumor characteristics. Kaplan-Meier survival analysis showed worse overall all-cause mortality (p = 0.02) and disease-free survival (p = 0.028) for tumors without any TMEM27 staining (0) compared to 0.5 or higher by log-rank test. CONCLUSION: The absence of TMEM27 expression is associated with more aggressive tumor characteristics and poorer all-cause mortality and disease-free survival in ccRCC. TMEM27 may be a useful biomarker to assess cancer prognosis. Further studies are needed to better assess if TMEM27 is protective in RCC, and its potential role in active surveillance and prediction of response to target therapy.

Systemic Immunological Determinants of Oncological Outcomes After Surgery for Localized Renal Cell Carcinoma.

INTRODUCTION & OBJECTIVES: In systemic therapy trials, a decreasing neutrophil-to-lymphocyte ratio (NLR) after treatment for metastatic renal cell carcinoma (RCC) has been associated with improved oncologic outcomes. Paradoxically, for patients with localized RCC treated with upfront surgery the opposite effect has been reported. We thus aimed to evaluate NLR dynamics on localized RCC recurrence. MATERIALS AND METHODS: Treatment naïve patients with localized RCC managed surgically between 2005 and 2020 were included. Preoperative NLR was calculated within 6-weeks prior to surgery and postoperative NLR was calculated between 4 and twelve-weeks after surgery. Patients were followed for disease recurrence, noting metastatic sites and postoperative infections. Cox regression were used to determine whether the relative change in postoperative NLR was associated with metastasis-free survival (MFS) and cancer-specific survival (CSS), adjusted for preoperative NLR. RESULTS: In the cohort of 3310 patients, 996 (30%) had postoperative NLR available. These patients generally had more advanced disease, with 100 developing metastases and 38 dying from kidney cancer. Median MFS follow-up was 4.4 years. Decreasing 2-month postoperative NLR was associated with non-statistically significant worse MFS and CSS (HR 0.79, 95% 0.50, 1.24, P = .3; HR 0.83, 95% C.I. 0.40, 1.73; P = .6). On sensitivity analysis, across all NLR measurements, with NLR as a time-dependent covariate, results were similar, with a declining NLR associated with adverse MFS (HR 0.85, 95% CI 0.69, 1.30, P-value = .10), though not meeting conventional levels of significance. CONCLUSION: In higher-risk localized RCC patients, postoperative NLR is not suitable as a biomarker for predicting recurrences.

A Targetable Myeloid Inflammatory State Governs Disease Recurrence in Clear-Cell Renal Cell Carcinoma.

It is poorly understood how the tumor immune microenvironment influences disease recurrence in localized clear-cell renal cell carcinoma (ccRCC). Here we performed whole-transcriptomic profiling of 236 tumors from patients assigned to the placebo-only arm of a randomized, adjuvant clinical trial for high-risk localized ccRCC. Unbiased pathway analysis identified myeloid-derived IL6 as a key mediator. Furthermore, a novel myeloid gene signature strongly correlated with disease recurrence and overall survival on uni- and multivariate analyses and is linked to TP53 inactivation across multiple data sets. Strikingly, effector T-cell gene signatures, infiltration patterns, and exhaustion markers were not associated with disease recurrence. Targeting immunosuppressive myeloid inflammation with an adenosine A2A receptor antagonist in a novel, immunocompetent, Tp53-inactivated mouse model significantly reduced metastatic development. Our findings suggest that myeloid inflammation promotes disease recurrence in ccRCC and is targetable as well as provide a potential biomarker-based framework for the design of future immuno-oncology trials in ccRCC. SIGNIFICANCE: Improved understanding of factors that influence metastatic development in localized ccRCC is greatly needed to aid accurate prediction of disease recurrence, clinical decision-making, and future adjuvant clinical trial design. Our analysis implicates intratumoral myeloid inflammation as a key driver of metastasis in patients and a novel immunocompetent mouse model. This article is highlighted in the In This Issue feature, p. 2221.

Genomic and Metabolic Hallmarks of SDH- and FH-deficient Renal Cell Carcinomas.

BACKGROUND: Succinate dehydrogenase-deficient and fumarate hydratase-deficient renal cell carcinomas (SDHRCC and FHRCC) are rare kidney cancers driven by loss of TCA cycle enzymes. OBJECTIVE: To define and compare the genomic and metabolomic hallmarks of SDHRCC and FHRCC. DESIGN, SETTING, AND PARTICIPANTS: We analyzed SDHRCC and FHRCC tumors with either immunohistochemical evidence of loss of protein expression or genomically confirmed biallelic inactivation of SDHA/B/C/D/AF2 or FH. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Somatic alterations were identified using clinical pipelines, with allele-specific copy number alterations (CNAs) identified using FACETS. Mass spectrometry-based metabolomic profiling was performed on available SDHRCC and FHRCC tumors. RESULTS AND LIMITATIONS: Tumors were analyzed for 42 patients (25 FHRCC, 17 SDHRCC). In the germline analysis, 16/17 SDHRCCs harbored a germline alteration in SDHB, whereas only 17/22 FHRCCs had pathogenic germline FH variants. SDHRCCs had a lower mutation burden (p = 0.02) and CNA burden (p = 0.0002) than FHRCCs. All SDHRCCs presented with deletion of chromosome 1p (overlapping SDHB), whereas FHRCCs demonstrated high but not ubiquitous loss of 1q (FH locus). Both SDHRCCs and FHRCCs exhibited significant idiopathic accumulation of the metabolite guanine. FHRCC tumors had elevated levels of urea cycle metabolites (argininosuccinate, citrulline, and fumarate), whereas SDHRCC tumors had elevation of numerous acylcarnitines. These characteristic metabolic changes allowed identification of a previously unrecognized SDH-deficient RCC. CONCLUSIONS: Despite sharing similar genetic etiology, SDHRCC and FHRCC represent distinct molecular entities with unique genetic and metabolic abnormalities. PATIENT SUMMARY: Kidney cancers driven by loss of the gene encoding either the succinate dehydrogenase or fumarate hydratase enzyme are rare. We sought to define and compare the genetic and metabolic features of these cancer entities.

Prevalence and Landscape of Actionable Genomic Alterations in Renal Cell Carcinoma.

PURPOSE: We report our experience with next-generation sequencing to characterize the landscape of actionable genomic alterations in renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: A query of our institutional clinical sequencing database (MSK-IMPACT) was performed that included tumor samples from 38,468 individuals across all cancer types. Somatic variations were annotated using a precision knowledge database (OncoKB) and the available clinical data stratified by level of evidence. Alterations associated with response to immune-checkpoint blockade (ICB) were analyzed separately; these included DNA mismatch repair (MMR) gene alterations, tumor mutational burden (TMB), and microsatellite instability (MSI). Data from The Cancer Genome Atlas (TCGA) consortium as well as public data from several clinical trials in metastatic RCC were used for validation purposes. Multiregional sequencing data from the TRAcking Cancer Evolution through Therapy (TRACERx) RENAL cohort were used to assess the clonality of somatic mutations. RESULTS: Of the 753 individuals with RCC identified in the MSK-IMPACT cohort, 115 showed evidence of targetable alterations, which represented a prevalence of 15.3% [95% confidence interval (CI), 12.7%-17.8%). When stratified by levels of evidence, the alterations identified corresponded to levels 2 (11.3%), 3A (5.2%), and 3B (83.5%). A low prevalence was recapitulated in the TCGA cohort at 9.1% (95% CI, 6.9%-11.2%). Copy-number variations predominated in papillary RCC tumors, largely due to amplifications in the MET gene. Notably, higher rates of actionability were found in individuals with metastatic disease (stage IV) compared with those with localized disease (OR, 2.50; 95% CI, 1.16-6.16; Fisher's P = 0.01). On the other hand, the prevalence of alterations associated with response to ICB therapy was found to be approximately 5% in both the MSK-IMPACT and TCGA cohorts and no associations with disease stage were identified (OR, 1.35; 95% CI, 0.46-5.40; P = 0.8). Finally, multiregional sequencing revealed that the vast majority of actionable mutations occurred later during tumor evolution and were only present subclonally in RCC tumors. CONCLUSIONS: RCC harbors a low prevalence of clinically actionable alterations compared with other tumors and the evidence supporting their clinical use is limited. These aberrations were found to be more common in advanced disease and seem to occur later during tumor evolution. Our study provides new insights on the role of targeted therapies for RCC and highlights the need for additional research to improve treatment selection using genomic profiling.

Immune checkpoint blockade in renal cell carcinoma.

Immune checkpoint blockade (ICB) is the foundation of current first-line therapies in patients with metastatic renal cell carcinoma (mRCC) with the potential for eliciting long-lasting remissions. With the expanding arsenal of ICB-based therapies, biomarkers of response are urgently needed to guide optimal therapeutic selection. We review the data behind ICB therapy in RCC, emerging biomarkers of response, and the evolving role of surgery in patients with mRCC.

Drp1 inhibition attenuates neurotoxicity and dopamine release deficits in vivo.

Mitochondrial dysfunction has been reported in both familial and sporadic Parkinson's disease (PD). However, effective therapy targeting this pathway is currently inadequate. Recent studies suggest that manipulating the processes of mitochondrial fission and fusion has considerable potential for treating human diseases. To determine the therapeutic impact of targeting these pathways on PD, we used two complementary mouse models of mitochondrial impairments as seen in PD. We show here that blocking mitochondrial fission is neuroprotective in the PTEN-induced putative kinase-1 deletion (PINK1(-/-)) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse models. Specifically, we show that inhibition of the mitochondrial fission GTPase dynamin-related protein-1 (Drp1) using gene-based and small-molecule approaches attenuates neurotoxicity and restores pre-existing striatal dopamine release deficits in these animal models. These results suggest Drp1 inhibition as a potential treatment for PD.

Paraquat neurotoxicity is mediated by the dopamine transporter and organic cation transporter-3.

The herbicide paraquat (PQ) has increasingly been reported in epidemiological studies to enhance the risk of developing Parkinson's disease (PD). Furthermore, case-control studies report that individuals with genetic variants in the dopamine transporter (DAT, SLC6A) have a higher PD risk when exposed to PQ. However, it remains a topic of debate whether PQ can enter dopamine (DA) neurons through DAT. We report here a mechanism by which PQ is transported by DAT: In its native divalent cation state, PQ(2+) is not a substrate for DAT; however, when converted to the monovalent cation PQ(+) by either a reducing agent or NADPH oxidase on microglia, it becomes a substrate for DAT and is accumulated in DA neurons, where it induces oxidative stress and cytotoxicity. Impaired DAT function in cultured cells and mutant mice significantly attenuated neurotoxicity induced by PQ(+). In addition to DAT, PQ(+) is also a substrate for the organic cation transporter 3 (Oct3, Slc22a3), which is abundantly expressed in non-DA cells in the nigrostriatal regions. In mice with Oct3 deficiency, enhanced striatal damage was detected after PQ treatment. This increased sensitivity likely results from reduced buffering capacity by non-DA cells, leading to more PQ(+) being available for uptake by DA neurons. This study provides a mechanism by which DAT and Oct3 modulate nigrostriatal damage induced by PQ(2+)/PQ(+) redox cycling.

D-ß-hydroxybutyrate is protective in mouse models of Huntington's disease.

Abnormalities in mitochondrial function and epigenetic regulation are thought to be instrumental in Huntington's disease (HD), a fatal genetic disorder caused by an expanded polyglutamine track in the protein huntingtin. Given the lack of effective therapies for HD, we sought to assess the neuroprotective properties of the mitochondrial energizing ketone body, D-ß-hydroxybutyrate (DßHB), in the 3-nitropropionic acid (3-NP) toxic and the R6/2 genetic model of HD. In mice treated with 3-NP, a complex II inhibitor, infusion of DßHB attenuates motor deficits, striatal lesions, and microgliosis in this model of toxin induced-striatal neurodegeneration. In transgenic R6/2 mice, infusion of DßHB extends life span, attenuates motor deficits, and prevents striatal histone deacetylation. In PC12 cells with inducible expression of mutant huntingtin protein, we further demonstrate that DßHB prevents histone deacetylation via a mechanism independent of its mitochondrial effects and independent of histone deacetylase inhibition. These pre-clinical findings suggest that by simultaneously targeting the mitochondrial and the epigenetic abnormalities associated with mutant huntingtin, DßHB may be a valuable therapeutic agent for HD.

Critical role of aquaporin-4 (AQP4) in astrocytic Ca2+ signaling events elicited by cerebral edema.

Aquaporin-4 (AQP4) is a primary influx route for water during brain edema formation. Here, we provide evidence that brain swelling triggers Ca(2+) signaling in astrocytes and that deletion of the Aqp4 gene markedly interferes with these events. Using in vivo two-photon imaging, we show that hypoosmotic stress (20% reduction in osmolarity) initiates astrocytic Ca(2+) spikes and that deletion of Aqp4 reduces these signals. The Ca(2+) signals are partly dependent on activation of P2 purinergic receptors, which was judged from the effects of appropriate antagonists applied to cortical slices. Supporting the involvement of purinergic signaling, osmotic stress was found to induce ATP release from cultured astrocytes in an AQP4-dependent manner. Our results suggest that AQP4 not only serves as an influx route for water but also is critical for initiating downstream signaling events that may affect and potentially exacerbate the pathological outcome in clinical conditions associated with brain edema.

Astrocytes and therapeutics for Parkinson's disease.

Astrocytes play direct, active, and critical roles in mediating neuronal survival and function in various neurodegenerative disorders. This role of astrocytes is well illustrated in amyotrophic lateral sclerosis (ALS), in which the removal of glutamate from the extracellular space by astrocytes confers neuroprotection, whereas astrocytic release of soluble toxic molecules promotes neurodegeneration. In recent years, this context-dependent dual role of astrocytes has also been documented in experimental models of Parkinson's disease. The present review addresses these studies and some potential mechanisms by which astrocytes may influence the neurodegenerative processes in Parkinson's disease, and in particular examines how astrocytes confer neuroprotection either through the removal of toxic molecules from the extracellular space or through the release of trophic factors and antioxidant molecules. In contrast, under pathological conditions, astrocytes release proinflammatory cytokines and other toxic molecules that are detrimental to dopaminergic neurons. These emerging roles of astrocytes in the pathogenesis of Parkinson's disease constitute an exciting development with promising novel therapeutic targets.

The organic cation transporter-3 is a pivotal modulator of neurodegeneration in the nigrostriatal dopaminergic pathway.

Toxic organic cations can damage nigrostriatal dopaminergic pathways as seen in most parkinsonian syndromes and in some cases of illicit drug exposure. Here, we show that the organic cation transporter 3 (Oct3) is expressed in nondopaminergic cells adjacent to both the soma and terminals of midbrain dopaminergic neurons. We hypothesized that Oct3 contributes to the dopaminergic damage by bidirectionally regulating the local bioavailability of toxic species. Consistent with this view, Oct3 deletion and pharmacological inhibition hampers the release of the toxic organic cation 1-methyl-4-phenylpyridinium from astrocytes and protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopaminergic neurodegeneration in mice. Furthermore, Oct3 deletion impairs the removal of the excess extracellular dopamine induced by methamphetamine and enhances striatal dopaminergic terminal damage caused by this psychostimulant. These results may have far-reaching implications for our understanding of the mechanism of cell death in a wide range of neurodegenerative diseases and may open new avenues for neuroprotective intervention.