Establishing and Maintaining an Extensive Library of Patient-Derived Xenograft Models

Abstract

Patient-derived xenograft (PDX) models have recently emerged as a highly desirable platform in oncology and are expected to substantially broaden the way in vivo studies are designed and executed and to reshape drug discovery programs. However, acquisition of patient-derived samples, and propagation, annotation and distribution of PDXs are complex processes that require a high degree of coordination among clinic, surgery and laboratory personnel, and are fraught with challenges that are administrative, procedural and technical. Here, we examine in detail the major aspects of this complex process and relate our experience in establishing a PDX Core Laboratory within a large academic institution.

Keywords: patient sample acquisition; patient-derived xenograft; patient-derived xenograft database; patient-derived xenograft implantation techniques; patient-derived xenograft propagation techniques.

Figure 1

Administrative, clinical, and research personnel involved in establishing patient-derived xenograft (PDX) models.

Figure 2

Flow chart detailing the numerous steps involved in the successful establishment, annotation, and propagation of novel patient-derived xenograft models.

Figure 3

Recommended minimum sample size and storage media for clinical samples used for establishment of patient-derived xenograft models. Saline solution: 0.9% sodium chloride. Tissue culture media: DMEM or RPMI-1640, 10% fetal bovine serum (FBS) and antibiotics. Freezing media: 10% DMSO, at least 20% FBS in DMEM.

Figure 4

Recommended media and equipment needed to process clinical samples ahead of their implantation into mice. Requirements vary depending on tissue sample and chosen processing modality. Saline solution: 0.9% Sodium Chloride. Tissue Culture Media: DMEM or RPMI-1640, 10% fetal bovine serum (FBS) and antibiotics. Freezing media: 10% DMSO, at least 20% FBS in DMEM. Abbreviations: PBS, phosphate buffer saline; ACK lysis buffer, ammonium chloride potassium lysis buffer.

Figure 5

Techniques recommended for processing clinical samples based on sample type and size.

Figure 6

Characteristics of common sample processing and implantation methods.

Figure 7

Factors influencing patient-derived xenograft take rate. Potential issues and corresponding suggestions for improvement. GVHD, graft versus host disease; OT, orthotopic; SC, subcutaneous.

Figure 8

Recommended number of tumor samples needed for patient-derived xenograft propagation based on propagation scope and tissue processing preferences. *Always implant 20% more mice to account for variability in tumor volume.

Figure 9

Patient-derived xenograft (PDX) database annotation should include clinical information pertinent to diagnosis, relevant medical and treatment history for each patient. Additionally data on histopathology and genomics characterization of both patient and PDX samples should be readily available. Finally, a timeline aligning patient treatment and time of PDX model generation can be very useful, especially for cases in which multiple PDXs have been generated from the same patient.

Figure 10

PDX database annotation should include information about sample processing and implantation, and records of PDX growth, propagation, and banking.

Figure 11

List of infrastructure, labor, and reagent costs likely to be incurred when establishing PDX models. IRB, Institutional Review Board; IACUC, Institutional Animal Care and Use Committee; IBC, Institutional Biosafety Committee; MTA, Material Transfer Agreement; IT, Information Technology; IHC, Immunohistochemistry.