Patient-derived Renal Cell Carcinoma Research Articles

Abstract C091: Uncovering genetic regulators of metabolic plasticity in renal cell carcinoma

Abstract We aim to offer new insights on the regulation of metabolic plasticity in renal cell carcinoma (RCC) and identify novel metabolic regulatory targets that can be used for potential treatment therapies of the disease. RCC affects an estimated 400,000 people worldwide each year with over 100,00 deaths annually that disproportionately affects racial/ethnic minorities in the United States. RCC is a term that covers an array of kidney cancer subtypes differing in incidence, histopathology, genetic and molecular alterations, as well as in clinical outcomes and prognoses. However, a common characteristic of many RCCs is that they are driven by metabolic rewiring, due to a high frequency of mutations in genes that regulate major metabolic processes in the cell. It was recently discovered that patient overall survival and prognosis has been linked to the expression of certain metabolic signatures in RCC tumor cells. Metabolic plasticity allows cancer cells to survive and adapt to different environments and metabolic stress conditions, such as nutrient deprivation. Therefore, exploring and exploiting metabolic rewiring in these cells may reveal genetic vulnerabilities and dependencies. This could lead to discovery of novel biomarkers and molecular targets that can be implicated as future therapeutic interventions for this disease. To this end, we applied functional genomic screening to expose genetic dependencies and vulnerabilities under different physiologic and metabolic conditions in patient derived medullary (PDM) RCC cells. The medullary RCC is a rare and aggressive RCC subtype that disproportionately affects the African American/Black population. We applied a CRISPR- based combinatorial screening platform that is based on co-expression of Cas9 and Cas12a nucleases and libraries of hybrid guide RNAs (hgRNA) to achieve ultra-efficient gene knockout (Aregger et al., 2021; Gonatopoulos-Pournatzis et al., 2020) in PDM RCC cells. Additionally, cells were screened under different media conditions that mimic human physiological nutrient conditions and a media deprived of lipids, one of the major metabolic substrates of the cell. By utilizing a genome-wide pooled CRISPR gene knockout screen we were able to systematically uncover genes required for cell survival and proliferation in a panel of patient-derived RCCs. We have begun to uncover genetic dependencies and major metabolic pathways that can be elucidated and exploited for future studies, such as those involving ferroptosis which is a targetable pathway for the development of cancer treatment therapies. Our findings demonstrate some of the key genetic drivers underlying cellular adaptations to different physiological environments and nutrient deprivation. In future studies we will further explore the relationship between different key metabolic regulatory genes in RCC and map for genetic interactions in major metabolic pathways. Citation Format: Chelsee Holloway, Josef Horak, Youngkyu Jeon, Michael Aregger. Uncovering genetic regulators of metabolic plasticity in renal cell carcinoma [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C091.

Patient-derived renal cell carcinoma organoids for personalized cancer therapy.

BackgroundKidney cancer is one of the most common solid tumors. The advancement of human kidney cancer research and treatment has been hindered by a lack of research models that faithfully recapitulate the diversity of the disease.MethodsWe established an effective three‐dimensional culture system for generating kidney cancer organoids from clinical renal cell carcinoma samples. Renal cell carcinoma (RCC) organoids were characterized by H&E staining, immunofluorescence, whole‐exome sequencing, RNA sequencing and single‐cell RNA sequencing. The use of RCC organoids in personalized cancer therapy was assessed by testing their responses to treatment drugs and chimeric antigen receptor T cells.ResultsUsing this organoid culture system, 33 kidney cancer organoid lines from common kidney cancer subtypes, including clear cell renal cell carcinoma (ccRCC), papillary renal cell carcinoma (pRCC), and chromophobe renal cell carcinoma (chRCC), were generated. RCC organoids preserved the histological architectures, mutational landscapes, and transcriptional profile of the parental tumor tissues. Single‐cell RNA‐sequencing revealed inter‐ and intra‐tumoral heterogeneity in RCC organoids. RCC organoids allowed for in vitro drug screening and provided a tool for assessing the efficacy of chimeric antigen receptor T cells.ConclusionsPatient‐derived RCC organoids are valuable pre‐clinical models for academic research and personalized medicine.

Abstract 3097: Patient-derived renal cell carcinoma xenografts engraftment identifies patients at risk of disease relapse, progression and death

Abstract Renal cell carcinoma (RCC) represents up to 90% of all kidney tumors, with 30% of patients presenting metastasis at diagnosis while 20-50% of those treated for curable localized disease experience recurrence. A better understanding of RCC biology is necessary to define the most efficient and personalized treatment or develop better antineoplastic drugs. Patient-derived xenografts (PDX) have emerged as one of the most promising approaches for that. This tool was generated by using surgical specimens of 87 patients implanted in immunodeficient NOD/SCID/gamma (NSG) mice, 17 of those subcutaneously and 70 at the renal subcapsular space. A total of 19 PDX developed only after orthotopic implantation and included 15 cases of clear cell RCC subtype, 3 cases of papillary subtype, and one unclassifiable tumor. One case of a PDX of a clear cell RCC recapitulated the phenotype of vena cava tumor thrombus extension that had been diagnosed in the source patient. The overall take rate was 27%, and the time to observed tumor growth varied from 5 to 13 months. An association between tumor growth and take rate was suggested by increasing take rates of 18%, 36%, and 100% among pT1 (pT1a + pT1b), pT3a, and pT3b stage tumors, respectively. PDX take rate was unrelated to tumor size (p =0.071). Patients whose tumor fragments engrafted experienced worse overall survival (OS) than those whose tumor fragments did not engraft (p = 0.003). Data also suggested a similar trend of association with metastasis-free survival (MFS) (p = 0.063). The median MFS for patients with successful PDX was 21.6 months (95% CI: 14.9, 28.3;), compared to a median of 34.4 months (95% CI: 30.4, 38.5 p = 0.003) among PDX engraftment-negative patients. PDX characterization by immunohistochemistry and targeted sequencing of the 21 most frequently mutated genes in the kidney indicated that all PDXs preserved RCC identity and major molecular alterations. From 19 PDX, the sequences of 13 patients’ tumor samples were compared with their respective PDX. In most patients (92% - 11/12), at least one mutation in patients’ tumor was identified in the PDX and in one case, no alterations were mapped. The most frequently mutated genes were VHL (50% - 6/12) and PBRM1 (41.7% - 5/12), followed by SETD2 (25% - 3/12), BAP1 and KDM5C (both 16.7% - 2/12), and ARID1A (8.3% - 1/12), indicating that all PDXs preserved RCC identity and major molecular alterations. These findings suggest that tumor engraftment capacity can identify patients at increased risk of relapse or death. Furthermore, pT1 stage tumors with the ability to engraft could also facilitate the identification of risk factors related to the rare pT1 cases with disease progression. These results suggest that the orthotopic xenograft model of RCC represents a suitable tool to study RCC biology, identify biomarkers, and test therapeutic candidates. Citation Format: Vilma Regina Martins, Adriano Beserra, Ethiene C. Estevan, Stephania Bezerra, Giovana T. Torrezan, Amanda Ikegani, Dellê Humberto, Isabela V. Cunha, Isabella T. Meira, Dirce M. Carraro, Primo N. Lara, Stenio Zequi, Tiago G. Santos. Patient-derived renal cell carcinoma xenografts engraftment identifies patients at risk of disease relapse, progression and death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3097.

Patient-Derived Renal Cell Carcinoma Xenografts Capture Tumor Genetic Profiles and Aggressive Behaviors

BACKGROUND: Patient-derived xenografts (PDX) have emerged as one of the most promising model systems to study cancer biology and to develop new antineoplastic drugs. Renal cell carcinoma (RCC) represents up to 90% of all kidney tumors, exhibits aggressive behavior, and has a propensity for metastasis. At diagnosis, 30% of patients with RCC have metastases, while up to 50% of those with localized disease treated with curative protocols experience recurrence. OBJECTIVE: This study aimed to establish an RCC PDX platform to identify novel clinical and molecular biomarkers of recurrence risk in order to facilitate precision medicine. METHODS: Tumor samples were obtained from surgical specimens of 87 RCC patients; fragments were implanted in immunodeficient NOD/SCID/gamma (NSG) mice. 17 Fragments were implanted subcutaneously in an initial group while a second group of 70 samples were implanted orthotopically in the subcapsular space. RESULTS: A total of 19 PDX developed only after orthotopic implantation, and included 15 cases of clear cell RCC subtype, 3 cases of papillary subtype, and 1 unclassifiable tumor. 1 PDX of clear cell RCC recapitulated the phenotype of vena caval tumor thrombus extension that had been diagnosed in the source patient. PDX characterization by immunohistochemistry and targeted sequencing indicated that all PDXs preserved RCC identity and major molecular alterations. Moreover, the capacity of tumor engraftment was a strong prognostic indicator for patients with locally advanced disease. CONCLUSION: Taken together, these results suggest that the orthotopic xenograft model of RCC represents a suitable tool to study RCC biology, identify biomarkers, and to test therapeutic candidates.

Abstract 1007: Patient-derived metastatic renal carcinoma cells are highly sensitive to in vitro Tumor Treating Fields (TTFields)

Abstract Background: Until the advent of checkpoint inhibitor (CI) therapies, renal cell carcinoma (RCC) was clinically challenging to treat given its radio- and chemotherapy resistance. Despite the advances with CIs, patients with brain metastases derived from RCC still face challenges with treatment due to limited brain penetration of CI compounds. Anti-mitotic TTFields therapy is FDA-approved for the treatment of glioblastoma and mesothelioma, and clinical trials are underway for the application of TTFields therapy to primary lung cancer as well as lung cancer brain metastases. In this study, in vitro TTFields were applied to patient-derived brain metastasis RCC cells to determine the potential efficacy of this emerging treatment modality. Methods: This study was approved by the Institutional Review Board. A single-cell suspension was generated from tumor tissues obtained from a patient with newly-diagnosed RCC brain metastasis (male, age 52, mutant p53). Cells were cultured in DMEM/F12 media with 10% fetal bovine serum and gentamicin. Prior to TTFields initiation, cells were plated on plastic coverslips (1×104cells/coverslip; n=8/group) and incubated overnight. Then, TTFields were applied at 200 kHz with a field intensity of ~1.6 V/cm for 14 days, with one group of coverslips maintained as untreated controls. At the conclusion of the experiment, cells were harvested, stained with acridine orange/propidium iodide and counted with a Cellometer K2 (Nexcelom Bioscience, Lawrence, MA) that provides viable cell counts and average cell diameter. Groups were compared with a two-tailed t-test (GraphPad Prism v9, GraphPad Software, San Diego, CA) with significance set at P<0.05. Results: Viable cell count per coverslip for the control group was 149,863 ± 85644 (mean ± SD; n=8) and for the TTFields (200 kHz) group was 1,426 ± 1345 (n=6, 2 coverslips had no cell recovery). Average cell diameter was 9.713 ± 0.6312 for the control group and 16.92 ± 2.903 for the TTFields group. TTFields application significantly reduced cell count (P=0.0012) and increased the average cell diameter (P<0.0001) compared to the controls. Conclusions: TTFields application (200 kHz) demonstrated efficacy by markedly reducing cell proliferation (i.e., decreased cell counts) in RCC. The increase in average cell diameter observed with TTFields is consistent with previously reported findings of other research groups also showing increases in cell volume with TTFields in multiple cancer types (brain, lung, pancreas, breast, ovarian, and cervical). This study is the first to demonstrate the efficacy of in vitro TTFields treatment in patient-derived RCC and suggests that patients with renal carcinoma brain metastases may benefit from TTFields therapy. Citation Format: Sharon K. Michelhaugh, Blake C. Walker, Susan Coombe, Sandeep Mittal. Patient-derived metastatic renal carcinoma cells are highly sensitive to in vitro Tumor Treating Fields (TTFields) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1007.

Functional inhibition of cancer stemness-related protein DPP4 rescues tyrosine kinase inhibitor resistance in renal cell carcinoma.

Tyrosine kinase inhibitors (TKIs) are used as targeted drugs for advanced renal cell carcinoma (RCC), although most cases eventually progress by acquiring resistance. Cancer stemness plays critical roles in tumor aggressiveness and therapeutic resistance, and dipeptidyl peptidase IV (DPP4) has been recently identified as a cancer stemness-related protein. A question arises whether DPP4 contributes to TKI efficacy in RCC. We established patient-derived RCC spheroids and showed that DPP4 expression is associated with stemness-related gene expression. TKI sunitinib resistance was rescued by DPP4 inhibition using sitagliptin or specific siRNAs in RCC cells and tumors. DPP4 expression can be inducible by retinoic acid and repressed by ALDH1A inhibition. Among type 2 diabetes patients with clinical RCC tumors, higher TKI efficacy is observed in those bearing DPP4high tumors treated with DPP4 inhibitors. This study provides new insights into TKI resistance and drug repositioning of DPP4 inhibitor as a promising strategy for advanced RCC.

Adoptive cell therapy of patient-derived renal cell carcinoma xenograft model with IL-15-induced γδT cells.

Adoptive transfer of γδ T cells is an attractive approach for cell-based immunotherapy in treatment of renal cell carcinoma (RCC). Interleukin-15 (IL-15) is the key physiological cytokine that regulates γδ T cell differentiation, proliferation and survival. In this work, we determined that IL-15 have the capacity to enhance the anti-tumoral functions of γδ T cells. IL-15 can induce the upregulation of cytotoxicity-associated molecules on the γδ T cell surface, incite γδ T cell proliferation and decrease apoptosis. Moreover, the enhanced cytotoxicity of IL-15-induced γδ T cell was dependent on the interaction of NKG2D and MICA. Most importantly, we found that IL-15-induced γδ T cells effectively suppressed the tumor growth in vivo and prolonged the survival time of RCC-bearing patient‑derived xenograft (PDX) mice. These results are important for the prospective use of γδ T cells in clinical practice when designing novel cell-based immunotherapies against RCC.

Facio‐genital dysplasia 5 (FGD5) regulates G‐protein coupled receptors (GPCRs) signaling to phosphatidylinositol 3 kinase (PI3K) pathway

IntroductionDrugs targeting the VEGF‐pathway have been approved to treat various cancers. However, tumors become resistant to this therapy due to the recruitment of alternative growth factors, acting via cognate endothelial cells (EC) receptor tyrosine kinases (RTK) or g‐protein coupled receptors (GPCR), to cue neo‐angiogenesis. Facio‐genital dysplasia 5 (FGD5) regulates vascular endothelial growth factor (VEGF)‐mediated angiogenesis, and VEGF receptor‐2 trafficking at the endosome. However, the role of FGD5 to regulate other pro‐angiogenic signaling pathways that co‐operate with VEGF has not been explored. Here, we identify a novel role of FGD5 to control G protein‐coupled receptor (GPCR) signaling.MethodsHuman umbilical vein endothelial cells (HUVEC) were mounted on microcarrier beads, suspended in fibrin gels, then co‐cultured with freshly harvested patient‐derived renal cell carcinoma (PD‐RCC) samples. The effect of FGD5 loss on sprouting angiogenesis was evaluated using RNAi against FGD5 in HUVEC. Stromal cell derived factor (SDF)‐1 was used as a model GPCR ligand to study the role of FGD5 in endothelial angiogenesis and PI3K signaling. Further, FDG5 domain‐deletant mutants were transiently overexpressed to rescue the effect of FGD5 knockdown on endothelial PI3K signaling. Western blot and confocal imaging were performed to readout the role of FGD5 in the GPCR/PI3K signaling pathway.ResultsLoss of FGD5 in HUVEC decreased sprouting angiogenesis stimulated by growth factors released from PD‐RCCs. The defect in angiogenesis was accompanied by downregulation of the expression of endothelial tip cell specific marker genes. Knockdown of endothelial FGD5 abolished the SDF‐1 angiogenic effect and SDF‐1 signaling to PI3K‐β and Akt. Inhibition of Rac1, a Rho GTP‐binding protein required for PI3K‐β activity, recapitulated the signaling defects of FGD5 deficiency, suggesting that FGD5 may control PI3K‐β activity through Rac1‐GTP. Overexpression of Dbl (Rho guanine nucleotide exchange factor) domain‐deleted FGD5 (FGD5ΔDbl) reduced SDF‐1‐stimulated Akt phosphorylation, and failed to rescue defective PI3K signalling in FGD5‐deficient cells, indicating that the Dbl domain of FGD5 regulates the activity of PI3K‐β. PI3K‐β and phosphorylated Akt localized to early endosomes after SDF‐1 stimulation, but loss of FGD5 decreased endosomal phosphorylated‐Akt. Failure of Akt activation at PI3K‐β‐positive endosomes suggests a defect in PI3K‐β activity after FGD5 loss.ConclusionsWe identify a novel role of FGD5 to regulate GPCR signaling to PI3K‐β. FGD5 acts at an endosomal convergence node regulating RTK and GPCR angiogenic pathways that may serve as a target for anti‐angiogenic therapy.Support or Funding InformationUniversity of Alberta Doctoral Recruitment Scholarship, Translational Medicine Research Award, Alberta Graduate Excellence Scholarship, Canadian Cancer Society, Division of Nephrology

Establishment of patient-derived renal cell carcinoma (RCC) models based on orthotopic xenografts (PDX) and cancer stem cell (CSC) isolation to provide prognostic and predictive information.

e16055 Background: The introduction of VEGF/VEGFR- and mTOR, and immune checkpoint-targeted agents has radically changed metastatic RCC treatment; however, predictive biomarkers are still lacking and the potential for curative impact of such treatments in earlier disease stages is hotly debated. To identify potential diagnostic, prognostic, and predictive biomarkers, we developed patient-derived preclinical RCC models based on PDX obtained from freshly dissociated cancer tissues and combining isolation of cell populations endowed with self renewal and multi-lineage differentiation abilities (CSC). Methods: 182 surgical RCC specimens (clear cell, n = 110; papillary type I/II, n = 23, chromophobe/oncocytoma, n = 26, other, n = 23; stage I-III, n = 124, stage IV, n = 28, n/a n = 30) were collected; tumor spheroids were obtained and characterized in 57 cases, using a stem-cell isolating medium supplemented with EGF/b-FGF; 30 cancer samples were orthotopically injected in immunocompromised mice and were able to engraft in 67% of cases (G3-G4 cases more frequently than G1-G2 cases, p = 0.04). Results: PDX tumors recapitulated histological appearance, sarcomatoid features when they were present, and tumor heterogeneity of their human counterpart; interestingly, PDX engraftment was significantly correlated with shorter DFS in the corresponding patient population (p = 0.12). We conducted proteomic analysis by Reverse Phase Protein Array (RPPA) in 21 patient-derived CSC models in vitro: a panel of established (HIF, VEGFR, mTOR) and novel (EGFR(Y1148)), AKT, PI3K) oncogenic signals were deregulated in our isolated cell populations; molecular endpoints were correlated with grading and with angiogenesis and mTOR pathways (p < 0.05). Data analysis is ongoing to ascertain whether specific RPPA-signatures can potentially complement clinical prognostic information and suggest candidate biomarkers and potential targets for therapy. Conclusions: In the era of personalized therapy, the combined use of PDX and RPPA from tumor specimens may be very useful for drug testing and patient stratification in RCC.

Metabolic barriers to immunotherapy in renal cell carcinoma.

11560 Background: Cancer cells can inhibit effector T cells through both immunomodulatory receptors and alteration of the tumor microenvironment as a result of cancer metabolism. A majority of patients treated with immune checkpoint inhibitors recently approved by the FDA fail to exhibit a clinical response. The extent to which metabolic conditions within the tumor impede T cell activation and anti-tumor effector function in renal cell carcinoma (RCC) are unknown. Methods: Under the IACUC protocol M1600005-00, BALB/c or Rag mice were subcutaneously injected with 100,000 Renca cells obtained from ATCC and growth monitored by caliper measurements in 3 dimensions every 3 days. In vivoPD-1 blockade was performed by 200 mcg/i.p. injection every 3 days using purified mPD-1 (BioXcell, J43). Deidentified tissue donations from patients with RCC were collected under the IRB protocol #151549 and processed into single cell suspensions following mechanical dissociation for the functional assays indicated below. Results: Through work with Rag deficient mice lacking functional B and T cells, we have established that tumor growth is regulated in a T cell dependent manner as evidenced by earlier formation and faster tumor growth. In a syngeneic mouse model of RCC (RenCa), we find that inhibition of PD-1 delays tumor growth and size. Tumor infiltrating lymphocytes (TILs) were abundant in patient-derived RCC, but are phenotypically distinct and are impaired both functionally and metabolically from healthy control. Instead of efficient use of aerobic glycolysis, TILs fail to increase glucose metabolism, and instead display increased reactive oxygen species (ROS) and mitochondrial dysfunction. CD8 effector cells found in tumors have notable differences in mitochondrial morphology compared to healthy control CD8 T cells by electron microscopy and immunofluorescence where CD8 TIL are punctate and dispersed throughout the cell while healthy control CD8 mitochondria are fused in networks. Thus bypassing metabolic defects may partially restore TIL activation. Conclusions: Preclinical data suggests that improved understanding of metabolic dysfunction in TILs of RCC may allow for combined therapies to improve response rates of checkpoint inhibition in this disease.

Resistance to Antiangiogenic Therapies by Metabolic Symbiosis in Renal Cell Carcinoma PDX Models and Patients.

SummaryAntiangiogenic drugs are used clinically for treatment of renal cell carcinoma (RCC) as a standard first-line treatment. Nevertheless, these agents primarily serve to stabilize disease, and resistance eventually develops concomitant with progression. Here, we implicate metabolic symbiosis between tumor cells distal and proximal to remaining vessels as a mechanism of resistance to antiangiogenic therapies in patient-derived RCC orthoxenograft (PDX) models and in clinical samples. This metabolic patterning is regulated by the mTOR pathway, and its inhibition effectively blocks metabolic symbiosis in PDX models. Clinically, patients treated with antiangiogenics consistently present with histologic signatures of metabolic symbiosis that are exacerbated in resistant tumors. Furthermore, the mTOR pathway is also associated in clinical samples, and its inhibition eliminates symbiotic patterning in patient samples. Overall, these data support a mechanism of resistance to antiangiogenics involving metabolic compartmentalization of tumor cells that can be inhibited by mTOR-targeted drugs.

Abstract B02: Ultrasound evaluation of anti-angiogenic therapy on patient-derived renal cell carcinoma xenograft tumors in the chicken embryo model

Abstract Introduction: The avian embryo patient-derived xenograft (PDX) model's use as a platform for pre-clinical drug testing is a promising application. However, conventional methods of monitoring, such as tumor-take rates, light microscopy, and histology, either do not provide sufficient detail for in-depth therapy evaluation or are reserved for end-point analysis. Ultrasound monitoring permits non-destructive longitudinal evaluation of tumor growth, progression, and angiogenesis in the chorioallantoic membrane (CAM) xenograft ex ovo model. High-frequency ultrasound was selected for its low cost, lack of ionizing radiation, and high spatial and temporal resolutions. Methods: A subset of tumor initiating cells (RCC243) was isolated from a patient-derived parental renal carcinoma cell line (RCC22). Cells were grown to confluence, pelleted, and combined with an equal volume of Matrigel. On the ninth day of embryonic development (EDD-9), the CAM surface of 8 animals was pierced, and 10µL of the cell-Matrigel mix was deposited into the opening. Half of the embryos were treated every two days with 10µL of TAK-441, a Hedgehog inhibitor with hypothesized anti-angiogenic effects. Three-dimensional anatomical (B-mode) and contrast-enhanced images were acquired using a Vevo 2100 ultrasound system (VisualSonics Inc.) equipped with a 20 MHz linear array transducer. On EDD-18, tumor volumes were assessed using the B-mode images. The CAM vasculature was then cannulated with a glass capillary needle, and a 50µL solution of Vevo MicroMarker (VisualSonics Inc.) microbubble contrast agent (2 x 109 microbubbles/mL) was injected in a pulsatile manner. Tumor blood perfusion (blood volume, velocity, and flow) was then assessed using destruction-reperfusion contrast ultrasound. Image analysis was performed within manually segmented tumor volumes. Results: Hedgehog inhibition of RCC243 tumors via TAK-441 therapy produced a significant decrease in mean tumor volume (vehicle: 187.68 ± 69.55 mm3 vs. treatment: 78.94 ± 52.35 mm3; p < 0.05) and blood flow (vehicle: 645.7 ± 261.5 mm3/min vs. treatment: 190.8 ± 133.4 mm3/min; p < 0.05). There was a non-significant trend of reduced blood volume (vehicle: 97.0 ± 64.7 mm3 vs. treatment: 33.7 ± 23.8 mm3; p = 0.12), and flow velocity (vehicle: 6.34 ± 1.07 mm/s vs. treatment: 5.52 ± 1.18 mm/s; p = 0.34) in the treated tumors. Conclusions: This proof of principal study shows that tumors implanted in an ex ovo chick CAM model can successfully be imaged using high-frequency ultrasound and quantitative measures of tumor volume, blood volume, velocity and flow can be obtained. Responses to anti-angiogenic therapy can be successfully quantified. This approach to therapy evaluation is inexpensive and permits observation of tumor-induced angiogenesis over a 9 day timeframe. Citation Format: Matthew R. Lowerison, Chantalle J. Willie, Siddika Pardhan, Nicholas E. Power, Ann F. Chambers, Hon S. Leong, James C. Lacefield. Ultrasound evaluation of anti-angiogenic therapy on patient-derived renal cell carcinoma xenograft tumors in the chicken embryo model. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Angiogenesis and Vascular Normalization: Bench to Bedside to Biomarkers; Mar 5-8, 2015; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl):Abstract nr B02.

Real-time measurement of hyperpolarized lactate production and efflux as a biomarker of tumor aggressiveness in an MR compatible 3D cell culture bioreactor.

We have developed a 3D cell/tissue culture bioreactor compatible with hyperpolarized (HP) (13)C MR and interrogated HP [1-(13)C]lactate production and efflux in human renal cell carcinoma (RCC) cells. This platform is capable of resolving intracellular and extracellular HP lactate pools, allowing the kinetic measurement of lactate production and efflux in the context of cancer aggressiveness and response to therapy. HP (13)C MR studies were performed on three immortalized human renal cell lines: HK2, a normal renal proximal tubule cell line from which a majority of RCCs arise, UMRC6, a cell line derived from a localized RCC, and UOK262, an aggressive and metastatic RCC. The intra- (Lacin ) and extracellular (Lacex ) HP lactate signals were robustly resolved in dynamic (13)C spectra of the cell lines due to a very small but reproducible chemical shift difference (0.031 ± 0.0005 ppm). Following HP [1-(13)C]pyruvate delivery, the ratio of HP Lacin /Lacex was significantly lower for UOK262 cells compared with both UMRC6 and HK2 cells due to a significant (p < 0.05) increase in the Lacex pool size. Lacin /Lacex correlated with the MCT4 mRNA expression of the cell lines, and inhibition of MCT4 transport using DIDS resulted in a significant reduction in the HP Lacex pool size. The extension of these studies to living patient-derived RCC tissue slices using HP [1,2-(13)C2]pyruvate demonstrated a similarly split lactate doublet with a high Lacex pool fraction; in contrast, only a single NMR resonance is noted for HP [5-(13)C]glutamate, consistent with intracellular localization. These studies support the importance of lactate efflux as a biomarker of cancer aggressiveness and metastatic potential, and the utility of the MR compatible 3D cell/tissue culture bioreactor to study not only cellular metabolism but also transport. Additionally, this platform offers a sophisticated way to follow therapeutic interventions and screen novel therapies that target lactate export.

Renal cell carcinoma avatar mouse models for the personalized cancer therapy era.

e15627 Background: Anti-angiogenic (AA) drugs are the cornerstone of fist-line (FL) treatment in renal cell carcinoma (RCC). While several mechanisms of resistance to AA have been described, second line (SL) therapies are disappointing with short PFS reported. A recent strategy makes use of individual patient-derived tumor models in animals for drug testing simultaneously with that patient’s FL and SL treatments (AVATAR). The predictive value of each specific AVATAR for that same original patient will be key in order to predict SL treatment response in the clinic trying to help in decision making in this setting. Methods: We generated a unique panel of patient-derived RCC mouse models based on orthotopic implantation of primary renal tumor biopsies or metastasis directly obtained from patients. Sunitinib FL treatment followed by different SL treatments are evaluated in each mouse model. Response to treatments in these models and molecular profiling in search of predictive factors of response/resistance wi...

Abstract 1192: Establishment and characterization of a new patient-derived renal cell carcinoma xenograft panel

Abstract Objective: Patients with advanced kidney cancer have a poor prognosis. The majority of patients develops treatment resistance towards Standard of Care (SoC) drugs within months. The successful development of novel personalized therapies depends on the availability of preclinical models with high clinical relevance. Our aim was to establish a panel of patient-derived renal cell carcinoma xenograft models for translational research. Methods: Specimens from primary and metastatic renal cell carcinoma tumors from consenting patients were collected after surgery and transplanted subcutaneously to immunodeficient mice within 24 hours. Tumor engraftment was followed for an initial period of up to 4 months. Successful engrafted patient-derived tumors were subsequently passaged to further mice. HE stained tumor sections were histopathologically examined to assess morphological concordance between patient tumor and PDX model. Renal cell carcinoma marker expression was determined by immunohistochemistry. Stably growing xenografts were tested for sensitivity towards SoC drugs, such as Avastin, Sunitinib, Sorafenib and Everolimus. Response to treatment was evaluated by comparing growth inhibition of treated in relation to untreated tumors. Primary tumors and the derived xenografts are currently under characterization for common oncogenic mutations using the Illumina TruSeq Amplicon Cancer Panel. Results: Nearly 200 tumor samples were transplanted since 2011. To date, 30% were successfully engrafted in immunodeficient mice and further patient-derived tumors are presently under establishment. Engraftment rates of samples from pT3 and pT4 tumors were higher (34%) than those from pT1 and pT2 tumors (12%). Two tumor samples which were pre-treated before surgery engrafted so far (11%). We show that specific tumor histology and renal cell carcinoma marker expression remained preserved over the passages. The drug sensitivity testings revealed a heterogeneous response to SoC treatments with Sunitinib (79% significant growth inhibition) and Everolimus (64%) as most effective treatments in the PDX models. Avastin showed a significant growth inhibition in 57% whereas Sorafenib was effective in 36% of the RCC models. We are furthermore presenting the individual gene mutation status of each RCC model. Conclusions: Our newly established patient-derived renal cell carcinoma panel provides a novel tool for the investigation of mechanisms of drug resistance and sensitivity in kidney cancer, biomarker research and the development of new therapeutic approaches. Citation Format: Susanne Flechsig, Annika Wulf-Goldenberg, Christian Schmees, Burkhard Jandrig, Jörg Hennenlotter, Jens Bedke, Martin Schostak, Andrew Crockford, Marco Gerlinger, James Larkin, Charles Swanton, Zoltan Szallasi, Iduna Fichtner, Jens Hoffmann. Establishment and characterization of a new patient-derived renal cell carcinoma xenograft panel. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1192. doi:10.1158/1538-7445.AM2014-1192

Establishing a human renal cell carcinoma tumorgraft platform for preclinical drug testing.

Traditionally, xenograft models have been used to study tumors in vivo. However, their utility is reduced by the use of tumor cell lines for implantation. Tumorgrafts (TGs; also known as patient-derived xenografts (PDXs)), which involve patient-derived tumor samples, are increasingly recognized as more representative models than traditional xenografts. Furthermore, we showed previously that renal cell carcinoma (RCC) TGs retain the histology, gene expression, DNA copy number alterations, mutations and treatment responsiveness of patient tumors. In skilled hands, implantations require ≤5 min per mouse, and TGs typically grow to 1 cm in 1-4 months. Here we outline the process of implantation of patient-derived RCC samples into the kidneys of immunodeficient mice, as well as the s.c. implantation for preclinical drug testing, including guidelines for the design and execution of drug trials. TGs have extensive applications besides therapeutic studies and may identify biomarkers and mechanisms of resistance. In addition, they may provide insights into tumor biology.

MP35-15 DEVELOPING A PATIENT-DERIVED XENOGRAFT MODEL USING CHICKEN EMBRYOS TO PREDICT TARGETED THERAPY TUMOR RESISTANCE IN RENAL CELL CARCINOMAS

You have accessJournal of UrologyKidney Cancer: Basic Research III1 Apr 2014MP35-15 DEVELOPING A PATIENT-DERIVED XENOGRAFT MODEL USING CHICKEN EMBRYOS TO PREDICT TARGETED THERAPY TUMOR RESISTANCE IN RENAL CELL CARCINOMAS Clarisse R. Mazzola, Chantalle Willie, Connor MacMillan, Khurram M. Siddiqui, Michele Billia, Jonathan I. Izawa, Ann F. Chambers, James Brugarolas, Ahn Tram, Nicholas Power, and Hon S. Leong Clarisse R. MazzolaClarisse R. Mazzola More articles by this author , Chantalle WillieChantalle Willie More articles by this author , Connor MacMillanConnor MacMillan More articles by this author , Khurram M. SiddiquiKhurram M. Siddiqui More articles by this author , Michele BilliaMichele Billia More articles by this author , Jonathan I. IzawaJonathan I. Izawa More articles by this author , Ann F. ChambersAnn F. Chambers More articles by this author , James BrugarolasJames Brugarolas More articles by this author , Ahn TramAhn Tram More articles by this author , Nicholas PowerNicholas Power More articles by this author , and Hon S. LeongHon S. Leong More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1058AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Approximately 30% of patients with metastatic renal cell carcinoma (RCC) will have primary resistance to targeted agents. The remainder will develop resistance over a longer time course. Improved ability to predict patient response prior to the initiation of treatment may improve patient outcomes. Our aim was to develop a patient-derived xenograft model to determine the sensitivity of each RCC patient’s tumor cells to a defined targeted therapy prior to the start of systemic treatment. METHODS We developed a patient−derived xenograft model using chicken embryos that enables the investigator to evaluate the interplay of tumor angiogenesis, growth, and drug sensitivities. Seven patient-derived primary RCC cell lines were implanted into the chorioallantoic membrane (CAM, N>15/cell line) to assess the effect of sunitinib on tumor take ratios. Three of these cell lines are sensitive to sunitinib (XP206, XP158, XP185) and four are resistant to sunitinib (XP127, XP121, XP258, PF22), as determined previously in murine heterotopic models. A secondary cell line that is sensitive to sunitinib (786-0) was also implanted as a control. Each cell line was prepared for xenografting by mixing cell pellets with Matrigel and 10 uL of this mix was implanted into the CAM of day-9 chicken embryos. To evaluate sunitinib sensitivities in vivo, cell lines were pre−treated overnight with 5 uM of this drug. Intravital imaging was performed to assess tumor size. Tumor microvessel density was determined by histology of resected tumors. Tumor take rates were determined 6−8 days post implantation. RESULTS Using the 786-0 cell line, tumor take rates were 82% in vehicle treated tumors compared to 46% in sunitinib treated tumors. Using the 7 patient derived RCC cell lines implanted into the CAM, tumor take rates varied amongst cell lines (Table 1). Decreased tumor take rates were observed in sunitinib-sensitive cell lines treated with sunitinib, when compared to their vehicle-treated controls. Tumor xenografts underwent extensive angiogenesis as observed by IV injection of Dextran-Alexa555 (10 kDa size). CONCLUSIONS We believe our patient-derived xenograft model could be a useful tool for drug sensitivity evaluation, enabling the investigator to potentially individualize targeted treatments to each patient with metastatic RCC prior to initiating systemic therapy. Further studies will be performed using other drugs that are used in the treatment of RCCs. Table 1: Tumor Take Rates in our Patient-Derived Cell Lines Patient-Derived Cell Line Treatment Tumor Take Rate XP206-GFP Vehicle 68.8% (11/16) XP206-GFP Sunitinib 26.3% (5/18) XP185-GFP Vehicle 64.7% (11/17) XP185-GFP Sunitinib 25.0% (5/20) XP158-tdTomato Vehicle 59.1% (13/22) XP158-tdTomato Sunitinib 28.0% (7/25) XP121-GFP Vehicle 65.0% (13/20) XP121-GFP Sunitinib 52.4% (11/21) XP127-GFP Vehicle 58.8% (20/34) XP127-GFP Sunitinib 53.6% (15/28) XP258-GFP Vehicle 63.0% (17/27) XP258-GFP Sunitinib 65.2% (15/23) PF22-GFP Vehicle 21.6% (8/37) PF22-GFP Sunitinib 24.1% (7/29) © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e376 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Clarisse R. Mazzola More articles by this author Chantalle Willie More articles by this author Connor MacMillan More articles by this author Khurram M. Siddiqui More articles by this author Michele Billia More articles by this author Jonathan I. Izawa More articles by this author Ann F. Chambers More articles by this author James Brugarolas More articles by this author Ahn Tram More articles by this author Nicholas Power More articles by this author Hon S. Leong More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Abstract B50: A patient-derived renal cell carcinoma model as a platform for the identification of novel diagnostic markers and therapeutic targets

Abstract Clear-cell renal cell carcinoma (ccRCC) is highly resistant to conventional therapies and to date effective treatment is restricted to surgical resection. Pre-clinical in vitro and in vivo models, which accurately mimic this disease, are critical for the development of novel effective therapies. Previous attempts to culture ccRCC cells have been proven difficult and thus, only few ccRCC cell lines are currently available. In addition long-term culturing often causes loss of primary tumor characteristics including tumor heterogeneity. This might explain why in contrast to other tumor entities, tumor-initiating cell (TIC) subpopulations have so far not been reported for ccRCC. TICs have been associated with tumor progression, metastasis and drug-resistance. Consequently these cells have also been named cancer stem cells (CSCs). Furthermore, distinct combinations of genetic and epigenetic alterations result in profound inter-patient heterogeneity and can in part promote TIC activity. Therefore, the development and characterization of clinically relevant patient derived ccRCC-models would provide an experimental basis to study the complex mechanisms leading to and maintaining ccRCCs. Hence, we established a patient-derived serum-free spheroid culture system that can be used to propagate primary ccRCC cells. These ccRCC cells retain their tumor-initiating potential and mimic the human malignancy upon orthotopic injection into immunodeficient mice. They not only mirror the histological properties but also the molecular features of the parental tumor. Moreover, these cells show the capacity to form de novo metastasis in lungs, which is the most common metastatic site for ccRCC in patients. The established ccRCC cultures were then used as a screening platform for the identification of surface proteins, which are heterogeneously expressed among tumor cells. Functional in vitro and in vivo assays showed that subpopulations defined by expression of these markers also displayed distinct functional characteristics including TIC activity. Gene Set Enrichment Analysis (GSEA) revealed differences in the signaling networks active in these sub-populations. In addition, molecular and cellular assays addressed the significance of these pathways for the maintenance of ccRCC malignancy. Currently the identified surface markers and underlying pathways are validated as potential novel diagnostic and therapeutic targets. Therefore, our novel patient-derived serum-free spheroid culture system serves as a platform to expand patient derived ccRCCs. It further allows the analysis and characterization of different subpopulations, which may ultimately contribute to the understanding of the molecular basis underlying progression, therapy-resistance and metastasis of this disease. Citation Format: Teresa Rigo-Watermeier, Corinna Klein, Vanessa Vogel, Christian Eisen, Thomas Hoefner, Wilko Weichert, Sascha Pahernik, Markus Hohenfellner, Martin R. Sprick, Andreas Trumpp. A patient-derived renal cell carcinoma model as a platform for the identification of novel diagnostic markers and therapeutic targets. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr B50.

Abstract 2411: A combination trial of SGN-75 and everolimus in patients with CD70-positive metastatic renal cell carcinoma (RCC).

Abstract Background. SGN-75 is an antibody-drug conjugate composed of a humanized anti-CD70 mAb conjugated to the microtubule-disrupting agent MMAF via a plasma-stable maleimidocaproyl linker. Upon binding to CD70, SGN-75 internalizes and releases cys-mcMMAF, which binds tubulin and induces G2/M arrest and apoptosis. In a phase 1, dose-escalation trial of SGN-75 in patients with CD70-positive relapsed/refractory NHL or metastatic RCC, single-agent activity of SGN-75 was observed in both NHL and RCC patients (Thompson 2011). In RCC, objective responses were observed with SGN-75 administered IV every 3 weeks at doses of 2 and 3 mg/kg. In vitro synergy in target cell killing was observed when SGN-75 was combined with mTOR inhibitors (everoliumus, temsirolimus, or sirolimus), a PI3K/mTOR inhibitor (NVP-BEZ235), or a dual mTORC1/mTORC2 inhibitor (PP242), as assessed by the Chou-Talalay method (Lewis 2011). Consistent with this observation, xenograft experiments using RCC cell lines (786-O and UM-RC-3) and a patient-derived RCC model (108963P) also demonstrated significantly improved antitumor activity with the combination of SGN-75 and everolimus compared to either agent alone. Based on the clinical activity of SGN-75 observed in patients with metastatic RCC and the synergistic effects observed in combination with mTOR inhibitors in preclinical models, a phase 1b study of the combination of SGN-75 and everolimus was initiated in patients with CD70-positive metastatic RCC (ClinicalTrials.gov #NCT01677390). Methods. The primary objective of this phase 1 study is to evaluate the safety and tolerability, and to identify the MTD, of SGN-75 in combination with everolimus. Pharmacokinetics, immunogenicity, and antitumor activity will also be evaluated. Eligible patients are ≥18 years old with pathologically confirmed CD70-positive metastatic RCC on archived or fresh tumor biopsy. Patients must have previously received treatment with 1 or 2 VEGF-receptor TKIs and must not have received prior treatment with any mTOR inhibitor. Patients must have measurable disease as defined in RECIST Version 1.1. SGN-75 will be administered IV every 3 weeks at protocol-defined doses up to 2 mg/kg in combination with everolimus 10 mg daily. After establishing the MTD, an expansion cohort of 15 efficacy-evaluable patients will be enrolled and treated with a dose at or below the MTD to further characterize the safety and pharmacokinetic profile and to obtain a preliminary estimate of antitumor activity of the combination. Patients who achieve CR, PR, or SD will be eligible to continue treatment in the study until disease progression. Patients who achieve a response of SD or better and discontinue study treatment prior to disease progression will be followed for progression-free survival and all patients will be followed for overall survival. Citation Format: Nancy C. Whiting, Che-Leung Law, Tim Lewis. A combination trial of SGN-75 and everolimus in patients with CD70-positive metastatic renal cell carcinoma (RCC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2411. doi:10.1158/1538-7445.AM2013-2411

Combination of the ERK inhibitor AZD6244 and low-dose sorafenib in a xenograft model of human renal cell carcinoma

Sorafenib, a multikinase inhibitor, is currently used as monotherapy for advanced renal cell carcinoma (RCC). However, adverse effects associated with its use have been experienced by some patients. In this study, we examined the antitumor and antiangiogenic activities of low-dose sorafenib in combination with the MEK inhibitor AZD6244 (sorafenib/AZD6244) in a preclinical model of RCC. Primary RCC 08-0910 and RCC786-0 cells as well as patient-derived RCC models were used to study the antitumor and antiangiogenic activities of sorafenib/AZD6244. Changes of biomarkers relevant to angiogenesis and cell cycle were determined by western immunoblotting. Microvessel density, apoptosis and cell proliferation were analyzed by immunohistochemistry. Treatment of RCC 786-0 cells with sorafenib/AZD6244 resulted in G1 cell cycle arrest and blockade of serum-induced cell migration. Sorafenib/AZD6244 induced apoptosis in primary RCC 08-0910 cells at low concentrations. Invivo addition of AZD6244 to sorafenib significantly augmented the antitumor activity of sorafenib and allowed dose reduction of sorafenib without compromising its antitumor activity. Sorafenib/AZD6244 potently inhibited angiogenesis and phosphorylation of VEGFR-2, PDGFR-β and ERK, p90RSK, p70S6K, cdk-2 and retinoblastoma. Sorafenib/AZD6244 also caused upregulation of p27, Bad and Bim but downregulation of survivin and cyclin B1. These resulted in a reduction in cellular proliferation and the induction of tumor cell apoptosis. Our findings showed that AZD6244 and sorafenib complement each other to inhibit tumor growth. This study provides sound evidence for the clinical investigation of low-dose sorafenib in combination with AZD6244 in patients with advanced RCC.