G401 Xenograft Model

G401 / G402 Xenograft Models

Solid pediatric tumors, especially in hepatoblastoma and malignant rhabdoid kidney tumors (MRKT), are prone to relapse and unresponsiveness to therapy. MRKTs are particularly aggressive, rare, often found in children under the age of four, and are often accompanied with distant metastasis. This makes treatment innovation critical. The G401 cell line was established from a patient, 3 months of age, Caucasian, male, and diagnosed with a kidney carcinoma rhabdoid tumor. The G401 has been used in many renal cancer research studies. Megison et al. (PLoS ONE, 2014) used G401 cells in their evaluation of M002, an oncolytic neuroattenuated herpes simplex virus-1 (oHSV), in the treatment of solid pediatric tumors. M002 is capable of replicating in tumor cells but is incapable of infecting normal cells. It was found that M002 can decrease cell survival in hepatoblastoma and increase survival in renal xenograft models. Clinical Cancer Research released a 2016 study (Muscat et al.) using the G401 model to investigate the use of a histone deacetylase inhibitor (HDACi) in the treatment of malignant rhabdoid tumors (MRT). A common characteristic of MRTs is the homozygous inactivation or deletion of SMARCB1, a chromatin remodeling gene. Sustained low dose treatment of the HDACi panobinostat (LBH589) in vitro and in xenograft models resulted in morphology changes, changes to gene expression, calcification mediated tumor growth inhibition, histological ossification, and neuronal/renal differentiation changes (indicated via TUJ1 and PAX2 immunohistochemical staining). This data overall suggests that HDACi treatment in MRT cells induces terminal differentiation and inhibits self-renewal. Finally, the 2017 Pediatric Blood Cancer study by Kurmasheva et al. used G401 xenografts to characterize the EZH2 inhibitor tazemetostat (EPZ-6438) against pediatric tumors for developmental therapeutics. EFS distribution, survival, and tumor growth were monitored; these preclinical testing results demonstrated significant tazemetostat antitumor activity accompanied by a decrease in H3K27me3 levels. The G401 cell line is used to create the CDX (Cell Line Derived Xenograft) G401 xenograft mouse model. The G401 xenograft model has been used to investigate pediatric solid renal cancer characteristics and therapies.

G401 and G402 In Vivo Models

Renal leiomyoma is a rare pediatric renal tumor with most cases being reported in adults. Renal leiomyoma is a benign smooth muscle tumor, although can progress to the malignant renal leiomyoblastoma. On the other hand, Wilms tumors, or nephroblastomas, account for most pediatric renal cancer cases and arise from mesodermal precursors of metanephros (renal parenchyma). The G402 cell line was established from a female patient, 9 months of age, Caucasian, diagnosed with renal leiomyoblastoma. The G402 has been used in many renal cancer research studies. Wohrle et al. used G402 cells in the 2013 PLoS ONE study evaluating fibroblast growth factor receptors (FGFR) as targets for malignant rhabdoid tumors (MRTs) with SNF5-deleted mutations. SNF5 is involved in the SWI/SNF chromatin remodeling complex; data demonstrated loss of SNF6 is correlated to increased FGFRs and that treatment in xenografts with NVP-BGJ398, a FGFR inhibitor, blocks tumor progression. In 2013 Knutson released a PNAS study using the G402 model to evaluate the small molecule N-((4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl)-5-(ethyl(tetrahydro-2H-pyran-4-yl)amino)-4-methyl-4′-(morpholinomethyl)-[1,1′-biphenyl]-3-carboxamide, a EZH2 inhibitor, in MRTs. Treatment with this compound in vitro induced differentiation and apoptosis in SMARCB1-deleted MRT cells and in vivo induced tumor regression correlated to decreased lysine 27/histone H3 trimethylation. Overall data demonstrated the potential utilization of epigenetic cancer therapy via EZH2 inhibition. Finally, Brenca et al. (Molecular Cancer Therapeutics, 2013) used G402 among other cells to investigate the effect of SMARCB1/INI1 in epithelioid sarcoma. It was found that homozygous deletions of SMARCB1 contribute to epithelioid sarcoma pathogenesis including proliferation, migration, and decreased irradiation sensitivity. The G402 cell line is used to create the CDX (Cell Line Derived Xenograft) G402 xenograft mouse model. The G402 xenograft model has been used to investigate pancreatic cancer characteristics and therapies such as gemcitabine and erlotinib.

Basic Study Design

  1. G401/G402 cells are maintained in exponential growth phase under aseptic conditions.
  2. Cells are trypsinized and cell count viability is determined using a trypan blue exclusion assay (98% of cell viability is required).  
  3. Each mouse is singly subcutaneously injected into the right flank with 106 cells in 100 µL of a Matrigel-G401/G402 cell suspension.
  4. The injection sites are palpated up to three times weekly until tumors are established to an average size of 50-150 mm3 as measured via digital caliper.
  5. Animals are randomized into treatment groups. Administration of test compound is performed according to the pre-established treatment schedule.
  6. Mice weights are measured and recorded 3 times weekly; tumors are measured and recorded daily.
  7. End of study is reached when tumor size reaches 2,000 mm3 or the predetermined size limit per approved IACUC protocol.
  8. Final necropsy and tissue collections are performed for appropriate downstream analysis. Tumors are excised, weighed and documented by digital imaging. Tumors and tissues can be stabilized in RNAlater, snap frozen in LN2 or prepared for histology