National Cancer Institute pediatric preclinical testing program: Model description for in vitro cytotoxicity testing

Abstract

Background The National Cancer Institute (NCI) has established the Pediatric Preclinical Testing Program (PPTP) for testing drugs against in vitro and in vivo childhood cancer models to aid in the prioritization of drugs considered for early phase pediatric clinical trials. Procedures In vitro cytotoxicity testing employs a semi-automated fluorescence-based digital imaging cytotoxicity assay (DIMSCAN) that has a 4-log dynamic range of detection. Curve fitting of the fractional survival data of the cell lines in response to various concentrations of the agents was used to calculate relative IC50, absolute IC50, and Ymin values The panel of 23 pediatric cancer cell lines included leukemia (n=6), lymphoma (n=2), rhabdomyosarcoma (n=4), brain tumors (n=3), Ewing family of tumors (EFT, n=4), and neuroblastoma (n=4). The doubling times obtained using DIMSCAN were incorporated into data analyses to estimate the relationship between input cell numbers and final cell number. Results We report in vitro activity data for three drugs (vincristine, melphalan, and etoposide) that are commonly used for pediatric cancer and for the mTOR inhibitor rapamycin, an agent that is currently under preclinical investigation for cancer. To date, the PPTP has completed in vitro testing of 39 investigational and approved agents for single drug activity and two investigational agents in combination with various “standard” chemotherapy drugs. Conclusions This robust in vitro cytotoxicity testing system for pediatric cancers will enable comparisons to response data for novel agents obtained from xenograft studies and from clinical trials.

Activity of MM-398, Nanoliposomal Irinotecan (nal-IRI), in Ewing's Family Tumor Xenografts Is Associated with High Exposure of Tumor to Drug and High SLFN11 Expression

“…Relative IC 50 (rIC 50 ) was calculated based on NCI Pediatric Preclinical Testing Program (PPTP) guidelines (32). SLFN11 expression was also measured by Human Exon (HuEx) 1.0 ST Array (Affymetrix) in 17 EFT cell lines and expression measured by HuEx arrays correlated with expression by RT-PCR (r ¼ 0.62, P ¼ 0.007).…”

“…We assessed cytotoxicity of SN-38 using the DIMSCAN cytotoxicity assay as previously described (31,32) and SLFN11 expression by Taqman real-time reverse transcription-PCR (RT-PCR) as previously described (33) Table S1). Relative IC 50 (rIC 50 ) was calculated based on NCI Pediatric Preclinical Testing Program (PPTP) guidelines (32).…”

The impact of the written request process on drug development in childhood cancer

“…Until recently, pre-clinical assessments of new oncology drugs excluded pediatric cancer cell lines and model systems [10,11]. Little evidence exists to suggest that the efficacy of a new drug in an adult cancer may predict activity in a childhood malignancy.…”

A Review on Surgical Techniques and Organ Sparing Procedures in Bladder/Prostate Rhabdomyosarcoma

“…In the United States, Pediatric Preclinical Testing Program (PPTP) systematically evaluates new agents against relapsed childhood solid tumors and leukemias already. 40,41 Another promising development may be associated with the progress of regenerative medicine and construction of artificial neobladders using urinary epithelium and collagen matrix scaffolds, which is already on the experimental way in some centers. 42,43 In addition, composite cystoplasty, which entails the use of combined autologous urothelial cell sheets and deepithelialized smooth muscle segments from organs, such as the intestine, seems possible and has been explored.…”