Bladder Cancer Patient-derived Xenograft Research Articles

Enhanced chemo-photodynamic therapy of an enzyme-responsive prodrug in bladder cancer patient-derived xenograft models

Patient-derived xenograft (PDX) models are powerful tools for understanding cancer biology and drug discovery. In this study, a polymeric nano-sized drug delivery system poly (OEGMA)-PTX@Ce6 (NPs@Ce6) composed of a photosensitizer chlorin e6 (Ce6) and a cathepsin B-sensitive polymer-paclitaxel (PTX) prodrug was constructed. The photochemical internalization (PCI) effect and enhanced chemo-photodynamic therapy (PDT) were achieved via a two-stage light irradiation strategy. The results showed that the NPs@Ce6 had great tumor targeting and rapid cellular uptake induced by PCI, thereby producing excellent anti-tumor effects on human bladder cancer PDX models with tumor growth inhibition greater than 98%. Bioinformatics analysis revealed that the combination of PTX chemotherapy and PDT up-regulated oxidative phosphorylation and reactive oxygen species (ROS) generation, blocked cell cycle and proliferation, and down-regulated the pathways related to tumor progression, invasion and metastasis, including hypoxia, TGF-β signaling and TNF-α signaling pathways. Western blots analysis confirmed that proteins promoting apoptosis (Bax, Cleaved caspase-3, Cleaved PARP) and DNA damage (γH2A.X) were up-regulated, while those inhibiting apoptosis (Bcl-2) and mitosis (pan-actin and α/β-tubulin) were down-regulated after chemo-PDT treatment. Therefore, this stimuli-responsive polymer-PTX prodrug-based nanomedicine with combinational chemotherapy and PDT evaluated in the PDX models could be a potential candidate for bladder cancer therapy.

Patient-derived microvesicles/AIE luminogen hybrid system for personalized sonodynamic cancer therapy in patient-derived xenograft models

Sonodynamic therapy (SDT), as an efficient way of tumor treatment, has the advantages of deep tumor penetration and high therapeutic efficacy. However, developing efficient sonosensitizers are still challenging. AIEgen-based SDT is rarely reported and it is urgent to develop novel AIEgen-active sonosensitizers. Furthermore, the AIEgen-based theranostic system is promisingly needed to be proved on PDX models to be closer to the clinic. Herein, we constructed a novel AIEgen based SDT system and found that DCPy has advantages over traditional sonosensitizers in SDT. Then, a patient-derived MVs/AIEgen hybrid system (AMVs) prepared by electroporation was used for personalized SDT in bladder cancer patient-derived xenograft (PDX) models. Impressively, AMVs displayed the superior tumor targeting ability and efficient personalized SDT therapy on PDX models, both of which were much more improved compared with PLGA/AIEgens nanoparticles and cell line-derived micro vesicles. This work provides new ideas for both the design of AIE-active sonosensitizers and the SDT treatment of cancers, further expanding the potential clinical application of AIEgens in the future.

A bladder\xa0cancer\xa0patient-derived xenograft displays aggressive growth dynamics in vivo and in organoid culture

Bladder cancer is among the most prevalent cancers worldwide. Currently, few bladder cancer models have undergone thorough characterization to assess their fidelity to patient tumors, especially upon propagation in the laboratory. Here, we establish and molecularly characterize CoCaB 1, an aggressive cisplatin-resistant muscle-invasive bladder cancer patient-derived xenograft (PDX) and companion organoid system. CoCaB 1 was a subcutaneous PDX model reliably transplanted in vivo and demonstrated an acceleration in growth upon serial transplantation, which was reflected in organoid and 2D cell culture systems. Transcriptome analysis revealed progression towards an increasingly proliferative and stem-like expression profile. Gene expression differences between organoid and PDX models reflected expected differences in cellular composition, with organoids enriched in lipid biosynthesis and metabolism genes and deprived of extracellular components observed in PDXs. Both PDX and organoid models maintained the histological fidelity and mutational heterogeneity of their parental tumor. This study establishes the CoCaB 1 PDX and organoid system as companion representative tumor models for the development of novel bladder cancer therapies.

Targeting EphA2 in Bladder Cancer Using a Novel Antibody-Directed Nanotherapeutic.

Ephrin receptor A2 (EphA2) is a member of the Ephrin/Eph receptor cell-to-cell signaling family of molecules, and it plays a key role in cell proliferation, differentiation, and migration. EphA2 is overexpressed in a broad range of cancers, and its expression is in many cases associated with poor prognosis. We recently developed a novel EphA2-targeting antibody-directed nanotherapeutic encapsulating a labile prodrug of docetaxel (EphA2-ILs-DTXp) for the treatment of EphA2-expressing malignancies. Here, we characterized the expression of EphA2 in bladder cancer using immunohistochemistry in 177 human bladder cancer samples and determined the preclinical efficacy of EphA2-ILs-DTXp in four EphA2-positive patient-derived xenograft (PDX) models of the disease, either as a monotherapy, or in combination with gemcitabine. EphA2 expression was detected in 80–100% of bladder cancer samples and correlated with shorter patient survival. EphA2 was found to be expressed in tumor cells and/or tumor-associated blood vessels in both primary and metastatic lesions with a concordance rate of approximately 90%. The EphA2-targeted antibody-directed nanotherapeutic EphA2-ILs-DTXp controlled tumor growth, mediated greater regression, and was more active than free docetaxel at equitoxic dosing in all four EphA2-positive bladder cancer PDX models. Combination of EphA2-ILs-DTXp and gemcitabine in one PDX model led to improved tumor growth control compared to monotherapies or the combination of free docetaxel and gemcitabine. These data demonstrating the prevalence of EphA2 in bladder cancers and efficacy of EphA2-ILs-DTXp in PDX models support the clinical exploration of EphA2 targeting in bladder cancer.

Abstract A27: Fidelity of a PDX-CR model for bladder cancer

Abstract Current efforts for cancer drug discovery have predominantly been deterred by the lack of appropriate preclinical cancer models that recapitulate the characteristics of this complex disease. Patient-derived xenografts (PDXs) are widely recognized as a more physiologically relevant preclinical model than organoids and standard cell lines, and often resemble the original tumor histology, genetic profile, and gene-expression patterns. Despite these benefits, PDX models are limited by their variable engraftment rate, lack of sustained growth in vitro, low throughput for drug screening, lower amenability to experimental manipulation, and high cost. In this study, we utilized conditional reprogramming (CR) technology to generate four CR cell (CRC) lines from bladder cancer PDXs. The CR cells were then employed to evaluate the genetic status and drug sensitivity and compared with the parental PDX tumors. All the established CRC lines maintained parental mutations and allele frequencies without clonal drift. Moreover, the drug responses of the parental PDX tumors in vivo were retained in the established CRC lines in vitro. Altogether, CR technology offers the ability to generate cell lines and expand PDX cells without compromising fundamental biologic properties of the model, thereby allowing for in vitro use to reduce animal usage, variability, and study cost. Perhaps more importantly, the CR cell lines established here can be used for personalized high-throughput drug screening as well as for studying drug-resistance mechanisms. Citation Format: Abdul M. Mondal, Ai-Hong Ma, Guangzhao Li, Ewa Krawczyk, Lu Jie, Richard Schlegel, Chong-Xian Pan, Xuefeng Liu. Fidelity of a PDX-CR model for bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2019 May 18-21; Denver, CO. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(15_Suppl):Abstract nr A27.

Patient-Derived Urothelial Cancer Xenograft Models: A Systematic Review and Future Perspectives

BACKGROUND: Lack of appropriate models that recapitulate the diversity, heterogeneity, and tumor microenvironment of urothelial cancer (UC) is a limitation to preclinical models. Patient-derived xenograft (PDX) models are a promising tool to overcome some of these issues, and thus we present an up-to-date and comprehensive overview of UC PDX models to aid in their future use. OBJECTIVE: To provide an overview on methodology, applications and limitations as well as future perspectives on bladder cancer PDX models. METHODS: Literature searches using PubMed and Web of Science databases were performed for relevant articles according to the following MeSH terms: “urothelial carcinoma(s)” OR “urothelial cancer” OR “urothelial tumor” OR “bladder cancer(s)” OR “bladder carcinoma(s)” OR “transitional cell carcinoma(s)” AND “xenograft(s)” OR “xenotransplant” at December 6th, 2019. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: Of the 49 studies extracted, 41 studies after the year 2000 were finally analyzed. Published studies show that (1) UC PDX platforms retained the histology and genomic characteristics of the corresponding patient tumors. (2) UC PDX can be applied to ask various questions including to study the mechanisms of disease progression and treatment resistance, to develop novel drugs and biomarkers, as well as to potentially realize personalized drug selection. Recent topics of research using PDX have included the development of humanized mice as well as the use of 3D culture to complement some of the limitations of PDX models. CONCLUSIONS: UC PDX models serve as tools for understanding cancer biology, drug development and empowering precision medicine. The improvement of experimental systems using humanized mice to recapitulate the immune microenvironment of tumors will optimize UC PDX to study future questions in the field of immunotherapy.

Methionine Adenosyltransferase 1a (MAT1A) Enhances Cell Survival During Chemotherapy Treatment and is Associated with Drug Resistance in Bladder Cancer PDX Mice.

Bladder cancer is among the top ten most common cancers, with about ~380,000 new cases and ~150,000 deaths per year worldwide. Tumor relapse following chemotherapy treatment has long been a significant challenge towards completely curing cancer. We have utilized a patient-derived bladder cancer xenograft (PDX) platform to characterize molecular mechanisms that contribute to relapse following drug treatment in advanced bladder cancer. Transcriptomic profiling of bladder cancer xenograft tumors by RNA-sequencing analysis, before and after relapse, following a 21-day cisplatin/gemcitabine drug treatment regimen identified methionine adenosyltransferase 1a (MAT1A) as one of the significantly upregulated genes following drug treatment. Survey of patient tumor sections confirmed elevated levels of MAT1A in individuals who received chemotherapy. Overexpression of MAT1A in 5637 bladder cancer cells increased tolerance to gemcitabine and stalled cell proliferation rates, suggesting MAT1A upregulation as a potential mechanism by which bladder cancer cells persist in a quiescent state to evade chemotherapy.

Fidelity of a PDX-CR model for bladder cancer

Patient-derived xenografts (PDXs) are widely recognised as a more physiologically relevant preclinical model than standard cell lines, but are expensive and low throughput, have low engraftment rate and take a long time to develop. Our newly developed conditional reprogramming (CR) technology addresses many PDX drawbacks, but lacks many in vivo factors. Here we determined whether PDXs and CRCs of the same cancer origin maintain the biological fidelity and complement each for translational research and drug development. Four CRC lines were generated from bladder cancer PDXs. Short tandem repeat (STR) analyses revealed that CRCs and their corresponding parental PDXs shared the same STRs, suggesting common cancer origins. CRCs and their corresponding parental PDXs contained the same genetic alterations. Importantly, CRCs retained the same drug sensitivity with the corresponding downstream signalling activity as their corresponding parental PDXs. This suggests that CRCs and PDXs can complement each other, and that CRCs can be used for in vitro fast, high throughput and low cost screening while PDXs can be used for in vivo validation and study of the in vivo factors during translational research and drug development.

Abstract 1067: A patient-derived xenograft (PDX) platform for cancer translational, precision medicine and health disparity research

Abstract Introduction and Objective: This purpose of this program is to develop and characterize PDXs from multiple organ sites and patients of multiple ethnic backgrounds, and to make these resources available to the scientific community for translational, precision medicine, and health disparity research. Methods: PDXs were directly developed from patient cancer specimens, molecularly characterized with next-generation sequencing, and annotated with clinical information. Various aspects of its applications were tested. Results: UC Davis, working in collaboration with The Jackson Laboratory (JAX), has developed PDX models, reflecting a wide range of tumor types, from 150 of our patients. Each of these models is annotated with clinical and genomic information. The fidelity of these PDXs was validated by the retention of histopathological features and the conservation of genetic aberrations (i.e., 92-97%) of the original patient tumors in bladder cancer PDXs tested. Extensive preclinical studies showed that these PDXs could potentially be used to screen multiple therapeutic agents simultaneously to identify the most efficacious drugs or drug combinations, re-purpose FDA-approved drugs, decipher the mechanisms of primary resistance, decrypt the mechanisms of secondary resistance, guide drug development, and identify biomarkers. For drug repurposing, the EGFR/ERBB2 dual inhibitor lapatinib effectively prolonged the overall survival (OS) of mice carrying ERBB2+ bladder cancer PDXs from 18.4 days to 25.4 days (p=0.007). For screening of targeted therapy in a PDX carrying PI3K, ERBB2 and Src alterations, only a PI3K inhibitor (BEZ235) prolonged the OS (p<0.0001) while lapatinib and a Src inhibitor ponatinib had no effect. For biomarker development, DNA adduct levels correlated with cancer response to alkylating agents and this project has already been translated into a clinical trial. For determination of the mechanisms of secondary resistance, loss of tumor suppressor gene LSP1 expression was associated with secondary resistance to an inhibitor of the PI3K pathway which is commonly mutated in many cancers. With the support of the Minority PDX Development and Trial Center (M-PDTC) U54 grant, UC Davis will continue to establish over 200 PDX models from bladder, lung squamous cell, gastric and hepatocellular carcinoma, with >60% of the specimens coming from minority patients, for health disparity research. Conclusions: PDXs have great potential for cancer translational, precision medicine and health disparity research. The NCI-funded U54 center with minority PDXs is open for collaboration through the PDX Development and Trial Centers Research Network (PDXNet). Citation Format: Chong-Xian Pan, Hongyong Zhang, Ai-Hong Ma, Shuxiong Zeng, Maike Zimmermann, Clifford Tepper, Paul Henderson, Luis Carvajal-Carmona, Regina Gandour-Edwards, Moon Chen, Susan Airhart, Ralph de Vere Whtie. A patient-derived xenograft (PDX) platform for cancer translational, precision medicine and health disparity research [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 1067.

Patient-derived bladder cancer xenograft models reveal VEGF and CDK4 enhancing tumor metastasis behavior.

New strategies to treat advanced bladder cancer are urgently required. A patient-derived xenograft (PDX) model has become a useful tool to evaluate chemotherapeutics and investigate personalized cancer treatment options. In this study, fresh human bladder cancer specimens (C09303 and C21391) were transplanted subcutaneously into nude mice to establish PDX models. These models well retained pathological characteristics and molecular markers of the original tumor. Primary cells derived from C09303 were cultured and perfused into the bladders of nude mice to establish orthotopic xenograft models. Evident signals of lung and kidney metastases were detected by whole-body optical imaging. Gemcitabine displayed a significant therapeutic effect on the subcutaneous or orthotopic xenograft tumors of C09303. In vitro, matrigel invasion assays showed that C09303 primary culture cells are remarkably invasive. To study the metastatic properties of C09303, we sequenced the genomes of C09303 and C21391, and found that the expression of VEGF and CDK4 was significantly upregulated, and VEGF-knockdown or CDK4-knockdown C09303 cells showed attenuated invasiveness and migration. This PDX model revealed that VEGF and CDK4 enhanced tumor metastasis behavior, suggesting them as novel molecular therapeutic targets. This framework provides a tool for research on metastasis mechanism and individualized treatment for bladder cancer.

Abstract 908: Overexpression of nicotinamide N-methyltransferase confers gemcitabine resistance in bladder cancer

Abstract Bladder cancer is among the top ten most common cancers diagnosed, with about ~380,000 new cases and ~150,000 deaths per year reported worldwide. Platinum-based chemotherapy in combination with gemcitabine, a nucleoside analog, is a widely used treatment option for advanced bladder cancer. It has been shown that only ~50% of the patients with advanced bladder cancer respond to platinum-based therapy. Cancer cells often become non-responsive to therapy that once proved efficacious and are now drug resistant. Drug resistance represents a significant, ongoing challenge in eradicating cancer. We have employed a patient-derived bladder cancer xenograft (PDX) platform to further investigate the molecular mechanisms that contribute to gemcitabine-induced drug resistance in advanced bladder cancer. Transcriptome profiling of passage 4 bladder cancer xenograft tumors from 2 gemcitabine sensitive PDX lines (BL0440 & BL0293) was performed using RNA sequencing (RNAseq) analysis, before and after a 21-day cisplatin/gemcitabine drug treatment regimen. Key regulatory pathways and genes contributing to drug resistant bladder cancer have been identified and validated by overexpression in a 5637 bladder cancer cell line. RNA sequencing data has indicated significant differences between the transcriptional profiles of drug-sensitive and drug-resistant tumors. PDXs retained morphology and shared 92-97% of genetic alterations of parental cancer cells. We identified 106 genes >1.5 fold up-regulated and 45 genes >1.5 fold down-regulated in the drug resistant tumors compared to their drug sensitive counterparts. Of the genes that were significantly upregulated, two methyltransferase enzymes were further validated: Nicotinamide N-methyltransferase (NNMT) and methionine methyltransferase 1A (MAT1A). These genes were found to be contributors to gemcitabine-mediated drug resistance. 5637 cells overexpressing NNMT yielded a 200-fold increase in gemcitabine resistance relative to parental strain. In conclusion, chemoresistance to gemcitabine is associated with differential expression of genes and alteration of downstream signaling pathways. Upregulation of NNMT & MAT1A can potentially be used as novel biomarkers for subpopulations of drug resistant bladder cancer for which improved therapeutics can be developed. Future direction will likely include studies to elucidate exact molecular mechanisms by which cancer cells utilize methyltransferases to no longer respond to gemcitabine therapy. This work was conducted under the auspices of the USDOE by LLNL (DE-AC52-07NA27344). Citation Format: Kelly A. Martin, Aimy Sebastian, Nicholas R. Hum, Deepa K. Murugesh, Chong-xian Pan, Ai-Hong Ma, Ralph W. de Vere White, Gabriela G. Loots. Overexpression of nicotinamide N-methyltransferase confers gemcitabine resistance in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 908.

1078 - An extensive panel of patient-derived bladder cancer xenografts representing the various molecular subtypes of muscle-invasive bladder cancers (MIBC)

1078 - An extensive panel of patient-derived bladder cancer xenografts representing the various molecular subtypes of muscle-invasive bladder cancers (MIBC)

Bladder cancer rapid autopsy: A mechanism for collecting metastatic tumor tissue and establishing xenograft models of metastatic disease.

478 Background: Patients with metastatic bladder cancer have a poor prognosis with a median survival of only 9-15 months. Understanding the biology of metastatic bladder cancer has been historically difficult due to a paucity of specimens and models that recapitulate human disease. We established a bladder cancer rapid autopsy program to systemically acquire metastases, and build patient-derived xenograft (PDX) and organoid models for biological studies. Methods: Patients with metastatic bladder cancer were consented and a rapid autopsy was performed 2-6 hours after death to allow acquisition of normal and metastasis specimens. Frozen and formalin-fixed and paraffin embedded specimens were collected and pathological evaluation was performed on each specimen. Additionally, tumors were implanted subcutaneously into SCID mice to establish PDXs. Once PDXs were developed, PDXs were dissociated for companion organoid culture. Clinical history and treatment information was documented for each patient. Results: We have performed 10 bladder cancer rapid autopsies to date, and have acquired 105 metastatic and 45 normal specimens. The pathological subtypes of patients include urothelial cell carcinoma (5/10), squamous cell carcinoma (3/10), and plasmacytoid variant of urothelial carcinoma (2/10). The cohort has been treated BCG only (1/10), chemotherapy (3/10), and chemotherapy and immune checkpoint inhibitors (6/10). The leading site of metastasis was the liver (7/10) and lung (7/10), followed by lymph node (5/10), bone (5/10), intestine (4/10), and omentum (2/10). Half (5/10) of the patients had extensive liver metastases that allow acquisition of multiple tumor foci. For the first time, PDX and organoids from two independent metastases (omentum – CoCaB 14.1 and liver –CoCaB 14.2) from the same patient were successfully developed. Conclusions: This bladder cancer rapid autopsy program provides an important volume of metastatic tumor specimens for study. Importantly, the first bladder cancer PDX derived from metastasis has been developed. The availability of metastatic bladder cancer specimens, PDXs, and organoids will allow biological studies of advanced disease.

Characterization of human bladder cancer patient-derived xenograft in vivo and in organoids.

479 Background: To establish and molecularly characterize a human bladder cancer patient-derived xenograft (PDX) in vivo and in an organoid system derived from the PDX for preclinical studies. Methods: Two-mm3 bits of urothelial carcinoma originated from muscle invasive disease excised in cystectomy were implanted subcutaneously into male severe combined immunodeficient mice to establish PDXs. Established PDXs (CoCaB 1) were passaged subcutaneously in SCID mice and histopathology of each passage was compared with the originating tumor. Tumor size was measured weekly by caliper to determine the growth rate of PDXs from early (P1/P2) through late passage (P8/P9). Representative early and late passages were collected for organoid establishment. For both early and late passages, proliferation was assessed by Ki67 in PDXs and organoids, and cell cycle analysis and MTS assay specifically in organoids. RNA sequencing was performed to compare the fidelity of PDX and organoids vs. primary tumor. Results: Histologically, 16 of the 16 (100%) PDXs generated from early through late passage (1-2 tumors per passage) were similar to the original high-grade urothelial carcinoma. In vivo, the latency of PDX establishment decreased upon passage (9 weeks to take in early P1/2 vs. 2 weeks to take in late P8/9) and the growth rate increased upon passage. Concordantly, Ki67 proliferation index increased from 40% in P1 to 95% in P8 and was positively correlated with increasing passage (Spearman R=0.804, p=0.001). Similarly, in organoids, late passage demonstrated a shorter growth doubling time, higher Ki67 proliferation index, and faster progression through cell cycle. Transcriptional analysis showed that the PDX contained 81-92% human transcripts, whereas organoids contained >99% human transcripts. Conclusions: Bladder cancer PDXs histologically represented the originating disease. PDX and organoid systems demonstrated concordant increase in proliferation upon serial passages, suggesting clonal selection may take place in this aggressive tumor type. Despite more mouse stromal content in PDX, PDX and organoid represent two independent model systems with highly similar biological responses that allow therapeutic studies.

COX-2/sEH Dual Inhibitor PTUPB Potentiates the Antitumor Efficacy of Cisplatin.

Cisplatin-based therapy is highly toxic, but moderately effective in most cancers. Concurrent inhibition of cyclooxygenase-2 (COX-2) and soluble epoxide hydrolase (sEH) results in antitumor activity and has organ-protective effects. The goal of this study was to determine the antitumor activity of PTUPB, an orally bioavailable COX-2/sEH dual inhibitor, in combination with cisplatin and gemcitabine (GC) therapy. NSG mice bearing bladder cancer patient-derived xenografts were treated with vehicle, PTUPB, cisplatin, GC, or combinations thereof. Mouse experiments were performed with two different PDX models. PTUPB potentiated cisplatin and GC therapy, resulting in significantly reduced tumor growth and prolonged survival. PTUPB plus cisplatin was no more toxic than cisplatin single-agent treatment as assessed by body weight, histochemical staining of major organs, blood counts, and chemistry. The combination of PTUPB and cisplatin increased apoptosis and decreased phosphorylation in the MAPK/ERK and PI3K/AKT/mTOR pathways compared with controls. PTUPB treatment did not alter platinum-DNA adduct levels, which is the most critical step in platinum-induced cell death. The in vitro study using the combination index method showed modest synergy between PTUPB and platinum agents only in 5637 cell line among several cell lines examined. However, PTUPB is very active in vivo by inhibiting angiogenesis. In conclusion, PTUPB potentiated the antitumor activity of cisplatin-based treatment without increasing toxicity in vivo and has potential for further development as a combination chemotherapy partner. Mol Cancer Ther; 17(2); 474-83. ©2017 AACR.

Image-guided photo-therapeutic nanoporphyrin synergized HSP90 inhibitor in patient-derived xenograft bladder cancer model

Photodynamic therapy is a promising and effective non-invasive therapeutic approach for the treatment of bladder cancers. Therapies targeting HSP90 have the advantage of tumor cell selectivity and have shown great preclinical efficacy. In this study, we evaluated a novel multifunctional nanoporphyrin platform loaded with an HSP90 inhibitor 17AAG (NP-AAG) for use as a multi-modality therapy against bladder cancer. NP-AAG was efficiently accumulated and retained at bladder cancer patient-derived xenograft (PDX) over 7 days. PDX tumors could be synergistically eradicated with a single intravenous injection of NP-AAG followed by multiple light treatments within 7 days. NP-AAG mediated treatment could not only specifically deliver 17AAG and produce heat and reactive oxygen species, but also more effectively inhibit essential bladder cancer essential signaling molecules like Akt, Src, and Erk, as well as HIF-1α induced by photo-therapy. This multifunctional nanoplatform has high clinical relevance and could dramatically improve management for bladder cancers with minimal toxicity.

The Phosphatidylinositol 3-Kinase Pathway as a Potential Therapeutic Target in Bladder Cancer

Purpose: Activation of the PI3K pathway occurs in over 40% of bladder urothelial cancers. The aim of this study is to determine the therapeutic potential, the underlying action, and the resistance mechanisms of drugs targeting the PI3K pathway.Experimental Design: Urothelial cancer cell lines and patient-derived xenografts (PDXs) were analyzed for alterations of the PI3K pathway and for their sensitivity to the small-molecule inhibitor pictilisib alone and in combination with cisplatin and/or gemcitabine. Potential predictive biomarkers for pictilisib were evaluated, and RNA sequencing was performed to explore drug resistance mechanisms.Results: The bladder cancer cell line TCCSUP, which harbors a PIK3CA E545K mutation, was sensitive to pictilisib compared to cell lines with wild-type PIK3CA Pictilisib exhibited stronger antitumor activity in bladder cancer PDX models with PI3KCA H1047R mutation or amplification than the control PDX model. Pictilisib synergized with cisplatin and/or gemcitabine in vitro, significantly delayed tumor growth, and prolonged survival compared with single-drug treatment in the PDX models. The phosphorylation of ribosomal protein S6 correlated with response to pictilisib both in vitro and in vivo, and could potentially serve as a biomarker to predict response to pictilisib. Pictilisib activated the compensatory MEK/ERK pathway that likely contributed to pictilisib resistance, which was reversed by cotreatment with the RAF inhibitor sorafenib. RNA sequencing of tumors resistant to treatment suggested that LSP1 downregulation correlated with drug resistance.Conclusions: These preclinical results provide new insights into the therapeutic potential of targeting the PI3K pathway for the treatment of bladder cancer. Clin Cancer Res; 23(21); 6580-91. ©2017 AACR.

Patient-Derived Bladder Cancer Xenografts.

Patient-derived xenograft (PDX ) tumors are models developed by direct transplant of human tumors into immune-compromised hosts such as nude mice. These models retain the histological and genetic characteristics of the primary tumor and are considered a valuable platform for translational cancer research. This chapter describes the methodology to establish and propagate bladder cancer PDX model.

Abstract 97: RNA sequencing of bladder cancer patient-derived xenograft models identifies genes associated with chemoresistance

Abstract Background: Bladder cancer is among the top ten most common cancers, with about ~380,000 new cases and ~150,000 deaths per year worldwide. Platinum-based combination chemotherapy is commonly used to treat advanced bladder cancer. It has been shown that only ~50% of the patients with advanced bladder cancer respond to platinum-based therapy. Methods: We have utilized a patient-derived bladder cancer xenograft (PDX) platform to characterize the molecular mechanisms that contribute to resistance of gemcitabine-cisplatin combination therapy in advanced bladder cancer. We have also identified key regulatory pathways in our PDX models that can be targeted to treat chemotherapy resistant bladder cancer using RNAseq analysis. Transcriptome profiling of P0 (passage 0) bladder cancer xenograft tumors from 4 PDX lines (2 gemcitabine-cisplatin resistant lines and 2 drug sensitive lines) was performed by RNA-Seq analysis, before and after a 21-day cisplatin/gemcitabine drug treatment regimen. Results: The RNA-seq data has indicated significant differences between the transcriptional profiles of drug-sensitive and drug-resistant tumors. PDXs retained morphology and shared 92-97% of genetic alterations of parental cancer cells. We identified 333 genes >2 fold up or down regulated in the drug resistant tumors compared to the drug sensitive tumors. Significantly up-regulated genes in drug resistant tumors analyzed include metabolic enzymes ALDH2, ALDH3A1, ALDH4A1 and ALDH7A1, transporter proteins ABCA1, SLC1A4, SLC2A5, SLC30A1, SLC39A6, SLC7A5 and SLC9A3, Notch ligand JAG2, Growth hormone receptor GHR and transmembrane protein GPNMB. Consistent with the change of cell surface proteins such as GHR and GPNMB, the MAPK and the PI3K-AKT pathways were upregulated when PDXs became resistant to cisplatin treatment. Additional changes in gene expression based on RNA-seq data before and after drug treatment were also found. Conclusion: Chemoresistance to gemcitabine and cisplatin is associated with altered expression of several cell surface proteins and upregulation of the downstream signaling pathways. Targeting these cell surface proteins can possibly be harnessed to overcome chemoresistance. GPNMB is a type I transmembrane protein that has previously been shown to be up-regulated in many metastatic cancers including breast cancer. Potentially targeting GPNMB with glembatumumab vedotin, an antibody-drug-conjugate has shown promising results in treating several cancers including breast cancer and osteosarcoma. Further studies will elucidate whether targeting GPNMB is an effective strategy for the treatment of chemotherapy resistant bladder cancer. This study received funding by a developmental grant from the UCDCC. This work was conducted under the auspices of the USDOE by LLNL (DE-AC52-07NA27344). IM number: LLNL-688318 Citation Format: Kelly A. Martin, Nicholas R. Hum, Aimy Sebastian, Deepa K. Murugesh, Chong-Xian Pan, Ai-Hong Ma, Ralph de Vere White, Gaby Loots. RNA sequencing of bladder cancer patient-derived xenograft models identifies genes associated with chemoresistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 97. doi:10.1158/1538-7445.AM2017-97

Establishment and application of bladder cancer patient-derived xenografts as a novel preclinical platform

Establishment and application of bladder cancer patient-derived xenografts as a novel preclinical platform