Immune Checkpoint Molecule TIGIT Regulates Kidney T Cell Functions and Contributes to AKI

SIGNIFICANCE STATEMENT

T cells mediate pathogenic and reparative processes during AKI, but the exact mechanisms regulating kidney T cell functions are unclear. This study identified upregulation of the novel immune checkpoint molecule, TIGIT, on mouse and human kidney T cells after AKI. TIGIT-expressing kidney T cells produced proinflammatory cytokines and had effector (EM) and central memory (CM) phenotypes. TIGIT-deficient mice had protection from both ischemic and nephrotoxic AKI. Single-cell RNA sequencing led to the discovery of possible downstream targets of TIGIT. TIGIT mediates AKI pathophysiology, is a promising novel target for AKI therapy, and is being increasingly studied in human cancer therapy trials.

BACKGROUND

T cells play pathogenic and reparative roles during AKI. However, mechanisms regulating T cell responses are relatively unknown. We investigated the roles of the novel immune checkpoint molecule T cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) in kidney T cells and AKI outcomes.

METHODS

TIGIT expression and functional effects were evaluated in mouse kidney T cells using RNA sequencing (RNA-Seq) and flow cytometry. TIGIT effect on AKI outcomes was studied with TIGIT knockout (TIGIT-KO) mice in ischemia reperfusion (IR) and cisplatin AKI models. Human kidney T cells from nephrectomy samples and single cell RNA sequencing (scRNA-Seq) data from the Kidney Precision Medicine Project were used to assess TIGIT's role in humans.

RESULTS

RNA-Seq and flow cytometry analysis of mouse kidney CD4+ T cells revealed increased expression of TIGIT after IR injury. Ischemic injury also increased TIGIT expression in human kidney T cells, and TIGIT expression was restricted to T/natural killer cell subsets in patients with AKI. TIGIT-expressing kidney T cells in wild type (WT) mice had an effector/central memory phenotype and proinflammatory profile at baseline and post-IR. Kidney regulatory T cells were predominantly TIGIT+ and significantly reduced post-IR. TIGIT-KO mice had significantly reduced kidney injury after IR and nephrotoxic injury compared with WT mice. scRNA-Seq analysis showed enrichment of genes related to oxidative phosphorylation and mTORC1 signaling in Th17 cells from TIGIT-KO mice.

CONCLUSIONS

TIGIT expression increases in mouse and human kidney T cells during AKI, worsens AKI outcomes, and is a novel therapeutic target for AKI.

Predictive model for systemic recurrence following cisplatin-based neoadjuvant chemotherapy and radical nephroureterectomy for high risk upper tract urothelial carcinoma

INTRODUCTION

Neoadjuvant chemotherapy (NAC) is increasingly used prior to radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC). Systemic recurrence (SR) carries a dismal prognosis. We sought to determine risk factors associated with SR in this setting.

METHODS

We evaluated a multi-center database of patients with UTUC who received cisplatin-based NAC before RNU. Final pathology at RNU was dichotomized into ypT<2 vs ypT≥2. Univariable and multivariable analyses were performed to identify risk factors associated with SR. Three groups were defined based on the number of significant risk factors (groups 1, 2, 3 for 0-1, 2, 3 risk factors, respectively) and evaluated for recurrence-free survival (RFS) using the Kaplan-Meier method.

RESULTS

106 patients were identified between 2004 and 2018. Median age was 67.0 years [IQR = 61-73.3]; 57 (54%) and 49 (46 %) patients received MVAC and GC, respectively. Final pathological stage was ypT<2 in 57 (54%); 23% (24/106) had SR. On univariable analysis, pathological variables on final specimen including ypT≥2, lymphovascular invasion (ypLVI), and nodal involvement were associated with SR. On multivariable analysis, ypLVI OR = 4.1 (95% CI 1.2-13.6; P = 0.024) and pathological nodal involvement OR = 4.5 (95% CI 1.3-15.7; P = 0.017) were predictive of recurrence. Stratifying by the number of risk factors, the 2-year RFS was 95%, 55%, and 18% for groups 1, 2, and 3 respectively (log-rank <0.001).

CONCLUSION

This model evaluates the risk of SR following NAC and RNU to guide counseling and decision-making after surgery. Adverse pathological variable including ypLVI and nodal involvement, in combination with ypT-stage, are strongly associated with SR.

Improved identification of patients with oligometastatic clear cell renal cell carcinoma with PSMA-targeted 18F-DCFPyL PET/CT

OBJECTIVE

Complete surgical resection of metastatic sites has been shown to prolong survival in select patients with oligometastatic RCC. This treatment strategy is dependent upon the accurate characterization of a patient's extent of disease. The objective of this study was to explore the utility of PSMA-targeted ¹⁸F-DCFPyL PET/CT in patients with presumed oligometastatic clear cell RCC.

METHODS

This is a subset analysis of a prospective study in which patients with RCC were imaged with ¹⁸F-DCFPyL PET/CT (ClinicalTrials.gov identifier NCT02687139). In the present analysis, patients with oligometastatic clear cell RCC, defined as ≤ 3 metastatic lesions on conventional imaging, were evaluated. ¹⁸F-DCFPyL PET/CT scans were reviewed for sites of disease and compared to conventional imaging.

RESULTS

The final cohort included 14 patients with oligometastatic clear cell RCC. Conventional imaging revealed 21 metastatic lesions and 3 primary tumors. ¹⁸F-DCFPyL PET/CT detected 29 sites of metastatic disease and 3 primary tumors. Of the 21 metastatic lesions detected on conventional imaging, 17 (81.0%) had radiotracer uptake. Additionally, all 3 primary tumors had radiotracer uptake. In 4 (28.6%) patients a total of 12 more lesions were identified on ¹⁸F-DCFPyL PET/CT than conventional imaging. Notably, 3 (21.4%) patients were no longer considered oligometastatic. The detection rates of conventional imaging and ¹⁸F-DCFPyL PET/CT for identifying sites of disease were 66.7% and 88.9%, respectively.

CONCLUSIONS

PSMA-targeted PET/CT appears to aid in the identification of patients with oligometastatic clear cell RCC. If borne out in future studies, this suggests that PSMA-targeted imaging has the potential to help select candidates for metastasis-directed therapy.

Abstract 1358: Tumor-derived extracellular vesicles as kidney cancer biomarkers

Renal cell carcinoma (RCC) is a fairly common and lethal cancer. The wide variety of RCC histological subtypes constitutes a challenge in treatment decision-making. Exosomes are extracellular membrane vesicles that are produced by all cell types in physiological conditions. Extracellular vesicles (EVs) are now accepted as a mode of intercellular communication and transport proteins, RNAs, DNA, and lipids to surrounding and distant cells. The lipid bilayer membrane of the EVs helps to protect these cargos. EVs are involved in many pathological processes, such as cancer, and can be easily obtained through liquid biopsy. Currently, EVs are rarely considered as candidate biomarkers for kidney cancer. However, improvements in the characterization of tumor-derived EVs could lead to the implementation of blood- and urine-derived EVs as biomarkers in the management of oncologic patients. Since all organs, not just the tumor, contribute to EV population, the thoughtful discrimination of tumor-derived EVs remains an unmet need for the clinical application of this kind of liquid biopsy technology. To determine the contribution of the tumor to blood- and urine-derived EVs, we utilize a novel approach to isolate tissue-derived EVs in parallel with liquid biopsy-derived EVs. To our knowledge, only a handful of studies (only one in RCC) have studied EVs directly derived from tissue. We propose the use tissue-derived EVs to screen for candidate EV biomarkers in plasma and/or urine. We hypothesize that using tissue-derived EVs would increase the tumor specificity for the characterization of EVs as liquid biopsy biomarkers. We optimized a protocol in which we used tissue of RCC patients (normal kidney or tumor) to condition media and isolate tumor-derived EVs alone by ultracentrifugation. Additionally, we isolated plasma- and urine EVs by ultracentrifugation using standard protocols. Nanoparticle Tracking Analysis (NTA) showed normalized concentrations of &gt;2 x 109 particles/mL with a size distribution in the small EV-range. Transmission Electron Microscopy (TEM) images showed typical exosome morphology, with the characteristic cup-shaped membrane vesicles. Western Blot (WB) confirmed the presence of exosome markers. We successfully isolated EVs from human RCC and healthy kidney tissue. We will proceed with screening the EV-samples for candidate miRNA-biomarkers by multiplexed gene expression analysis, followed by confirmation of the candidate markers by RT-qPCR.

Citation Format: Richard C. Zieren, Liang Dong, Sarah R. Amend, Philip M. Pierorazio, Theo M. de Reijke, Kenneth J. Pienta. Tumor-derived extracellular vesicles as kidney cancer biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1358.

Inconsistent Detection of Sites of Metastatic Non-Clear Cell Renal Cell Carcinoma with PSMA-Targeted [18F]DCFPyL PET/CT

PURPOSE

To investigate the utility of prostate-specific membrane antigen (PSMA)-targeted [¹⁸F]DCFPyL positron emission tomography (PET)/X-ray computed tomography (CT) imaging for the detection of sites of disease in patients with metastatic non-clear cell renal cell carcinoma (RCC).

PROCEDURES

Eight patients with metastatic non-clear cell RCC underwent imaging with PSMA-targeted [¹⁸F]DCFPyL PET/CT. Imaged RCC histologic subtypes included papillary RCC (n = 3), chromophobe RCC (n = 2), unclassified RCC (n = 2), and Xp11 translocation RCC (n = 1). Using comparison to conventional CT and/or magnetic resonance imaging as reference, two radiologists with expertise in nuclear medicine identified putative sites of disease on [¹⁸F]DCFPyL PET/CT and classified each lesion as having no radiotracer uptake, equivocal uptake, or definitive uptake.

RESUTS

In total, 73 metastatic sites and 3 primary tumors compatible with sites of non-clear cell RCC were identified on conventional imaging. Metastatic sites of disease included lymph nodes (n = 40), venous thrombi (n = 3), pulmonary nodules (n = 10), bone lesions (n = 15), brain lesions (n = 3), and retroperitoneal masses (n = 2). Only 10 of the 73 lesions (13.7 %) were classified as having definitive radiotracer uptake (median SUV_max = 3.25, range = 1.2-9.5), 14 lesions (19.2 %) had equivocal uptake (median SUV_max = 2.85, range = 0.5-6.5), and 49 lesions (67.1 %) had no definitive uptake above background (median SUV_max = 1.7, range = 0.2-3.0). The three primary renal tumors demonstrated lower radiotracer avidity relative to surrounding normal renal parenchyma.

CONCLUSIONS

A small proportion of sites of non-clear cell RCC showed uptake of the PSMA-targeted radiotracer [¹⁸F]DCFPyL. Unlike for clear cell RCC, the results of this study indicate that PSMA-based PET is not appropriate for imaging other RCC subtypes.

Very-high-risk localized prostate cancer: definition and outcomes

BACKGROUND

Outcomes in men with National Comprehensive Cancer Network (NCCN) high-risk prostate cancer (PCa) can vary substantially-some will have excellent cancer-specific survival, whereas others will experience early metastasis even after aggressive local treatments. Current nomograms, which yield continuous risk probabilities, do not separate high-risk PCa into distinct sub-strata. Here, we derive a binary definition of very-high-risk (VHR) localized PCa to aid in risk stratification at diagnosis and selection of therapy.

METHODS

We queried the Johns Hopkins radical prostatectomy database to identify 753 men with NCCN high-risk localized PCa (Gleason sum 8-10, PSA >20 ng ml(-1), or clinical stage ≥T3). Twenty-eight alternate permutations of adverse grade, stage and cancer volume were compared by their hazard ratios for metastasis and cancer-specific mortality. VHR criteria with top-ranking hazard ratios were further evaluated by multivariable analyses and inclusion of a clinically meaningful proportion of the high-risk cohort.

RESULTS

The VHR cohort was best defined by primary pattern 5 present on biopsy, or ≥5 cores with Gleason sum 8-10, or multiple NCCN high-risk features. These criteria encompassed 15.1% of the NCCN high-risk cohort. Compared with other high-risk men, VHR men were at significantly higher risk for metastasis (hazard ratio 2.75) and cancer-specific mortality (hazard ratio 3.44) (P<0.001 for both). Among high-risk men, VHR men also had significantly worse 10-year metastasis-free survival (37% vs 78%) and cancer-specific survival (62% vs 90%).

CONCLUSIONS

Men who meet VHR criteria form a subgroup within the current NCCN high-risk classification who have particularly poor oncological outcomes. Use of these characteristics to distinguish VHR localized PCa may help in counseling and selection optimal candidates for multimodal treatments or clinical trials.

Comparison of biochemical recurrence-free survival between periprostatic and pelvic lymph node metastases of prostate cancer

OBJECTIVE

To assess the pathologic characteristics and prognostic significance of periprostatic lymph node (LN) metastasis of prostate cancer. The latter was performed by comparing biochemical recurrence (BCR)-free survival in cases of periprostatic LN metastasis versus matched patients showing pelvic LN metastasis.

METHODS AND MATERIALS

We identified 15 patients who underwent radical prostatectomy in our institution (1984-2011) showing positive periprostatic and negative pelvic LN with available follow-up information (group 1). These patients were matched 1:2 to patients with positive pelvic LN (group 2) for pertinent clinicopathologic parameters.

RESULTS

Main locations of positive periprostatic LN were posterior base and mid posterolateral. Overall higher rate of positive margins, smaller LN, and metastasis size were encountered in group 1 compared with group 2. At 5 years postprostatectomy, 69% of patients in group 1 were free of BCR, whereas 26% of those in group 2 remained BCR free, suggesting that patients with periprostatic node metastasis appeared to have a lower risk of BCR. However, the difference was not statistically significant (P = .072). The same was true when adjusted for the effect of prostate-specific antigen, surgical margin status, size of LNs, size of metastasis, age, and year of surgery.

CONCLUSION

Patients with periprostatic node metastasis may have a lower risk of BCR compared with those with metastasis to pelvic LN. Future analysis of larger cohorts will help establish the biologic significance of prostate cancer metastasis to periprostatic LN.