Services Provided and Model Protocol
Patient Derived Xenograft Services offers the following PDTX services:
Engraftment, expansion, characterization and archiving Patient-derived tumor xenografts.
Following receipt of the tumor tissue we will immediately process the tissue for engraftment, cryopreservation and analysis.
Archive—store frozen tissue, FFPE, DNA, RNA.
- Tissue will be cut into 3 mm3 pieces and frozen in cryopreservation medium. Long-term storage will be in liquid nitrogen.
- Tissue will be formalin fixed and embedded in paraffin for sectioning and histological examination. At the client’s request, tissue will be frozen in OTC.
- Tissue will be snap frozen in liquid nitrogen to be used for extraction of DNA, RNA and protein.
Implantation and engraftment—typically 2-4 months, possibly up to 6 months.
- Tissue will be immediately engrafted to establish the xenograft tumor.
- Establishment of patient-derived xenograft tumors will take between two and four months but can take as long as 6 months if necessary.
- Expansion—established PDTX tumors will be removed from the host and cut into 3 mm3 pieces.
- Tumor pieces will be cryopreserved, snap frozen and prepared for histological examination.
- Multiple tumor pieces will be engrafted into multiple host animals for expansion.
- Each re-engraftment is recorded as a passage.
- Each passage will be cryopreserved, prepared for histological examination and frozen for DNA and RNA extraction.
- When tumors reach the third passage they are ready for therapeutic studies.
Analysis—Specific methods of analysis will be discussed with the client prior to performing the analysis.
- At the minimum histological analysis will be performed for comparison to original tissue.
- Immunohistochemical/immunofluorescence staining will be performed to characterize expression of specific biomarkers as defined by the client.
- Genomic analysis: Varying levels of genomic analysis will be performed from characterization of gene amplification/deletion, genomic rearrangements, gene mutation to genome wide association studies (GWAS).
- Gene-expression analysis: Patient Derived Xenografting Services offers a wide variety of gene-expression profiling options. Expression of specific genes will be done using real-time quantitative PCR (TaqMan assays) and global transcriptome analysis will be done using RNA-seq analysis.
PDX tumor bearing mice available:
Specific Cancer Models available:
Murine models are described in our science of Patient-Derived Xenografting page here. Some commonly-used models for PDX experiments include:
- 6- to 7-week-old female BALB/c athymic (nude) mice
- 9-11 week old NOD/SCID immunocompromised mice
Clients choose a tumor tissue of interest, an animal (typically immunocompromised murine) model, and work with our experienced scientists to select the number and size of experimental groups. Once in-house, the animals are acclimatized to the vivarium and sorted according to body mass. The selected tissue is thawed and grafted into either the flank area or orthotopically into the area selected by the client. Tumor appearance and other clinical signs are monitored daily, and once tumors appear, the animals are sorted based on tumor volume.
Experimental dosing of desired compounds is initiated either when the mean tumor size reaches a defined volume (known as a staged study) or immediately after the xenograft is inserted (in an unstaged study). The animals are dosed according to the schedule determined by the client, and via client-selected administration route. Administration route options include:
- intratracheal, or
Other administration options available include the frequency of doses, and the duration of the dose administration. Patient Derived Xenograft services also offers a standard positive control option that utilizes cyclophosphamide, at a dosage of 50 mg/kg given by intramuscular injection to the control group daily for the selected study duration.
Experimental studies at Patient Derived Xenograft Services include daily observation of animals by experienced personnel, and typically tumor volume and body weight measurements performed every two days. Additional services available include tumor preservation and other histology, as well as terminal collection of blood sera.