Primary Patient-derived Tumor Xenograft Research Articles

Drug Screening of Primary Patient Derived Tumor Xenografts in Zebrafish.

Patient derived xenograft models are critical in defining how different cancers respond to drug treatment in an in vivo system. Mouse models are the standard in the field, but zebrafish have emerged as an alternative model with several advantages, including the ability for high-throughput and low-cost drug screening. Zebrafish also allow for in vivo drug screening with large replicate numbers that were previously only obtainable with in vitro systems. The ability to rapidly perform large scale drug screens may open up the possibility for personalized medicine with rapid translation of results back to clinic. Zebrafish xenograft models could also be used to rapidly screen for actionable mutations based on tumor response to targeted therapies or to identify new anti-cancer compounds from large libraries. The current major limitation in the field has been quantifying and automating the process so that drug screens can be done on a larger scale and be less labor-intensive. We have developed a workflow for xenografting primary patient samples into zebrafish larvae and performing large scale drug screens using a fluorescence microscope equipped imaging unit and automated sampler unit. This method allows for standardization and quantification of engrafted tumor area and response to drug treatment across large numbers of zebrafish larvae. Overall, this method is advantageous over traditional cell culture drug screening as it allows for growth of tumor cells in an in vivo environment throughout drug treatment, and is more practical and cost-effective than mice for large scale in vivo drug screens.

Drug Screening of Primary Patient Derived Tumor Xenografts in Zebrafish

Drug Screening of Primary Patient Derived Tumor Xenografts in Zebrafish

Novel Richter Syndrome Xenograft Models to Study Genetic Architecture, Biology, and Therapy Responses.

Richter syndrome represents the evolution of chronic lymphocytic leukemia into an aggressive tumor, most commonly diffuse large B-cell lymphoma. The lack of in vitro and in vivo models has severely hampered drug testing in a disease that is poorly responsive to common chemoimmunotherapeutic combinations as well as to novel kinase inhibitors. Here we report for the first time the establishment and genomic characterization of two patient-derived tumor xenograft (PDX) models of Richter syndrome, RS9737 and RS1316. Richter syndrome xenografts were genetically, morphologically, and phenotypically stable and similar to the corresponding primary tumor. RS9737 was characterized by biallelic inactivation of CDKN2A and TP53, monoallelic deletion of 11q23 (ATM), and mutations of BTK, KRAS, EGR2, and NOTCH1 RS1316 carried trisomy 12 and showed mutations in BTK, KRAS, MED12, and NOTCH2 RNA sequencing confirmed that in both cases >80% of the transcriptome was shared between primary tumor and PDX. In line with the mutational profile, pathway analyses revealed overactivation of the B-cell receptor, NFκB, and NOTCH pathways in both tumors, potentially providing novel tumor targets. In conclusion, these two novel models of Richter syndrome represent useful tools to study biology and response to therapies of this highly aggressive and still incurable tumor.Significance: Two patient-derived xenograft models of Richter syndrome represent the first ex vivo model to study biology of the disease and to test novel therapeutic strategies. Cancer Res; 78(13); 3413-20. ©2018 AACR.

Abstract 1035: A comprehensive patient-derived tumor xenograft (PDX) collection representing the heterogeneity of kidney, prostate and bladder cancers

Abstract Kidney, prostate and bladder cancers (KCa, PCa and BCa, respectively) represent 1 700 000 cases and 450 000 deaths worldwide per year, with an incidence rising yearly by 1-10%. Surgery is usually curative at early and localized stages but there are no efficient therapies at advanced and metastatic stages for any of them. Although genetically-modified and/or chemically-induced avatar models do exist for these cancers and may help to identify new therapeutic targets, they suffer from a lack of an extended biological concordance with the natural history and heterogeneity of the diseases. Patient-derived tumor xenograft models are now well recognized as reliably reproducing tumor heterogeneity and have become over the past few years the preclinical tools of choice to test drugs and identify biomarkers. Since 10 years, we are continuously developing a unique panel of PDX models for these major urological cancers. Tumor tissues along with normal corresponding tissues were obtained from patients at surgery. Patient informed consent and clinical history are available for all patients. Tumor tissues pieces were xenografted subcutaneously in the interscapular space of nude mice, and serially passaged into mice after the first engraftment, up to passage 10. To ensure model stability between primary tumors and tumors growing in mice but also from passage to passage, we performed various analyses at histopathological, genetic (short tandem repeat fingerprinting) and molecular (cDNA profiling) levels. In addition, growth characteristics and responses to standards of care (SOCs) were examined. Finally, specific molecular characteristics were also explored including expression of the androgen receptor, PSA and pan-cytokeratin for PCa models and hotspot mutations of FGFR3, PIK3CA, K/N/H-RAS for BCa models. Up to now, we have xenografted 336 (on 569 samples), 247 and 152 KCa, PCa and BCa tumor tissues, and developed 30 (8.9% success rate), 6 (2.1%) and 30 (19.7%) PDX models, respectively. We recently published part of the KCa PDX models collection (Lang et al., Oncotarget, 2016). Characterization studies showed that PDX models are stable at all levels analyzed considering concordance to primary tumors and from passage to passage; and less than 5% of genes were differentially expressed between the primary tumors and PDX tumors at various passages. Responses to SOCs recapitulated the clinical state. Only for KCa PDX models, the take rate was correlated to tumor stage and grade, and sarcomatoid components. Importantly, several molecular subtypes were defined in our collection of BCa PDX models including PDXs with FGFR3 mutations and PDXs of basal subtype, the most aggressive one. Overall, this panel of PDX models for urological cancers should definitely help to find molecularly guided targeted therapies for these still incurable cancers at metastatic stages. Citation Format: Hervé Lang, Claire Béraud, Myriam Lassalle, Isabelle Bernard-Pierrot, Véronique Lindner, Yves Allory, Michel Soulié, Xavier Gamé, Pascal Rischmann, Eric Potiron, François Radvanyi, Philippe Lluel, Thierry Massfelder. A comprehensive patient-derived tumor xenograft (PDX) collection representing the heterogeneity of kidney, prostate and bladder cancers [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 1035.

Genomic profiling is predictive of response to cisplatin treatment but not to PI3K inhibition in bladder cancer patient-derived xenografts.

PurposeEffective systemic therapeutic options are limited for bladder cancer. In this preclinical study we tested whether bladder cancer gene alterations may be predictive of treatment response.Experimental designWe performed genomic profiling of two bladder cancer patient derived tumor xenografts (PDX). We optimized the exome sequence analysis method to overcome the mouse genome interference.ResultsWe identified a number of somatic mutations, mostly shared by the primary tumors and PDX. In particular, BLCAb001, which is less responsive to cisplatin than BLCAb002, carried non-sense mutations in several genes associated with cisplatin resistance, including MLH1, BRCA2, and CASP8. Furthermore, RNA-Seq analysis revealed the overexpression of cisplatin resistance associated genes such as SLC7A11, TLE4, and IL1A in BLCAb001. Two different PIK3CA mutations, E542K and E545K, were identified in BLCAb001 and BLCAb002, respectively. Thus, we tested whether the genomic profiling was predictive of response to a dual PI3K/mTOR targeting agent, LY3023414. Despite harboring similar PIK3CA mutations, BLCAb001 and BLCAb002 exhibited differential response, both in vitro and in vivo. Sustained target modulation was observed in the sensitive model BLCAb002 but not in BLCAb001, as well as decreased autophagy. Interestingly, computational modelling of mutant structures and affinity binding to PI3K revealed that E542K mutation was associated with weaker drug binding than E545K.ConclusionsOur results suggest that the presence of activating PIK3CA mutations may not necessarily predict in vivo treatment response to PI3K targeted therapies, while specific gene alterations may be predictive for cisplatin response in bladder cancer models and, potentially, in patients as well.

Abstract IA28: Innovative PDX models for studying immunotherapy of cancer

Abstract PDX models are limited by the absence of a complete and functional immune system. Overwhelming evidence now exists to suggest that immune cells play an integral role in the development and maintenance of tumors. Without a functional immune system, PDX models cannot reflect the dynamic processes of tumor-immune surveillance and immune-mediated editing, limiting the translation of antitumor results obtained in these models. Another important consequence of lacking an immune system is the impossibility to test in these models anticancer drugs that directly target immune cells. To overcome these important limitations, PDX models with human immune systems are needed. There are different approaches to enrich PDX models with human immune cells: engrafting human peripheral blood mononuclear cells, engrafting hematopoietic stem cells, or engrafting primary patient-derived tumor xenografts with human tumor infiltrating lymphocytes. All these alternatives have different strengths and weaknesses that are important to know for obtaining preclinical results that are meaningful for clinical translation. Citation Format: Miguel F. Sanmamed. Innovative PDX models for studying immunotherapy of cancer. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA28.

Abstract P4-07-04: PARP1/2 inhibition in a subset of triple negative breast cancer (TNBC) patient-derived tumor xenografts (PDX) identifies predictive biomarkers of response

Abstract Background: BRCA1/2 mutation carriers (gBRCA) have a higher risk of breast or ovarian cancer, since BRCA1/2 mutation results in impaired high-fidelity DNA repair by homologous recombination (HR) and subsequently genetic instability. In non-gBRCA TNBC, HR deficiency occurs at the somatic level, by means of BRCA1 mutation, BRCA1 epigenetic loss or mutation in other HR-associated genes. Because PARP1/2 inhibitors (PARPi) are well-tolerated and active anti-cancer agents in the advanced setting of gBRCA tumors, we sought to expand their applicability by identifying response biomarkers in TNBC. Methods: We have assessed the antitumor response of the PARP1/2 inhibitor olaparib as single agent in a panel of 12 primary and advanced TNBC PDX models. On PDXs exhibiting primary sensitivity to olaparib, we have developed models of acquired resistance by continuous exposure to the drug and identifying progression on treatment. We have characterized the models through targeted sequencing and the analysis of the hypermethylation and expression levels of BRCA1 transcript to find potential correlates of drug-sensitivity. Results: Three out of 12 PDXs (25%) treated with single agent olaparib, exhibit tumor regression or disease stabilization. BRCA1 is hypermethylated in two of these PARPi-sensitive TNBC PDX models and is associated with loss of BRCA1 mRNA expression. The third PARPi-sensitive TNBC PDX harbors a frameshift, heterozygous PALB2 mutation, which is no longer detected in the acquired resistance PDX model. Acquired resistance in the hypermethylated PDXs is under study as well as the duration of response compared to gBRCA PDX models. Conclusions: Our study highlights that somatic HR-deficiency is frequent in TNBC and provides the basis of sensitivity to PARPi. Citation Format: Serra V, Cruz C, Bruna A, Ibrahim YH, Vivancos A, Vivancos A, Nuciforo P, Bellet M, Gómez P, Pérez JM, Saura C, Vidal M, Serres X, Rueda OM, Peg V, Caldas C, O'Connor MJ, Baselga J, Cortés J. PARP1/2 inhibition in a subset of triple negative breast cancer (TNBC) patient-derived tumor xenografts (PDX) identifies predictive biomarkers of response. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-07-04.

Tumor P-Glycoprotein Correlates with Efficacy of PF-3758309 in in vitro and in vivo Models of Colorectal Cancer

P-glycoprotein (P-gp), a member of the ATP-binding cassette transporter family, is overexpressed in a number of different cancers and some studies show that P-gp overexpression can be correlated to poor prognosis or therapeutic resistance. Here we sought to elucidate if PF-3758309 (PF-309), a novel p-21 activated kinase inhibitor, efficacy was influenced by tumor P-gp. Based on in vitro proliferation data, a panel of colorectal cancer cell lines were ranked as sensitive or resistant and ABCB1 (P-gp) expression was evaluated by microarray for these cell lines. P-gp expression was determined by western blot and activity determined by rhodamine efflux assay. Knock down of P-gp and pharmacologic inhibition of P-gp to restore PF-309 activity was performed in vitro. PF-309 activity was evaluated in vivo in cell line xenograft models and in primary patient derived tumor xenografts (PDTX). Mice were treated with 25 mg/kg PF-309 orally, twice daily. On the last day of treatment, tumor and plasma were collected for PF-309 analysis. Here we show that ABCB1 gene expression correlates with resistance to PF-309 treatment in vitro and the expression and activity of P-gp was verified in a panel of resistant cells. Furthermore, inhibition of P-gp increased the sensitivity of resistant cells, resulting in a 4–100-fold decrease in the IC50s. Eleven cell line xenografts and 12 PDTX models were treated with PF-309. From the cell line xenografts, we found a significant correlation between ABCB1 gene expression profiles and tumor response. We evaluated tumor and plasma concentrations for eight tumor models (three cell line xenografts and five PDTX models) and a significant correlation was found between tumor concentration and response. Additionally, we show that tumor concentration is approximately fourfold lower in tumors that express P-gp, verified by western blot. Our in vitro and in vivo data strongly suggests that PF-309 efficacy is influenced by the expression of tumor P-gp.