Preclinical Modelling and Therapeutic Development for Other Cancer Indications

Division Of Basic Sciences - Nci

Investigators

Linked publications, trials & patents

Abstract

To support research advancements in Dr. Laurie Krug's lab at the CCR HIV and AIDS Malignancy Branch, CAPR has embarked on a project aimed at developing pdx modes from Kaposi sarcoma (KS) biopsies. As the clinical KS samples proven themselves to display very low take rate and slow proliferation in recipient mice, specific set of standard operating procedures have been developed for both clinical sample collections and pdx implantations to increase success rate in deriving stable pdx xenografts. In addition to optimizing the experimental protocols, we have performed evaluation of various growth factors and employed humanized IL-6 transgene expressing NSG recipient mouse sub-strain to implant 9 skin biopsies and 3 gastrointestinal tract colonoscopy biopsies from KS patients. Currently, the pdx models undergo comparative histopathology and biomarker evaluation top confirm the identity and explore potential therapeutic vulnerabilities of these tumors towards potential selection of treatment modalities in teh upcoming drug treatment studies. Alternative procedures for more reliable and sustainable propagation of slowly growing in mice KS tumors are also being evaluated, such as implantation of biopsies into renal capsule. CAPR pancreatic modelling group made progress towards developing an unmet need model for a rare pancreatic malignancy type known as pancreatic acinar cell carcinoma (PACC). To achieve this ambitious objective, we have either imported and characterized two constituent alleles of PACC model (Cela1-CreERT and APC-flox) or engineered in house using CRISPR/Cas9 genome editing technology a conditional allele for Id3 gene. We have evaluated the excision signatures of inducibility of Cela1-CreERT transgenic line by intercrossing these mice onto a ROSA26-R3-tdTom reporter line. Subsequent analyses of induced tdTom fluorescence in bi-transgenic Cela1-CreERT/ROSA26-R3-tdTom animals confirmed high level of Cre-mediated excision in pancreatic acini, but not in ducts or islet located cells, albeit also indicated constitutive activity of Cre recombinase in pancreatic acini, irrespective of tamoxifen induction. The final assembly of the tri-allelic PACC model is currently underway by intercrossing Cela1CreERT recombinase-expressing allele with conditional alleles for Id3 and APC tumor suppressor genes. In collaboration with Dr. del Rivero (CCR Pediatric Oncology Branch) and Dr. Sunita Agarwal (NIDDK), CAPR completed a large-scale cancer prevention study to examine the protective effect of metformin administration again formation of pancreatic neuroendocrine tumors in Multiple Endocrine Neoplasia/MEN1 model that appeared to be a highly penetrant model for MEN1 malignancy. Two cohorts of MEN1-flox/RIP-Cre animals (n=6/cohort) have been prepared and treated ad libitum either with regular drinking water or drinking water containing 2mg/ml metformin. Animals have been monitored for up to 12 months on treatment by longitudinal ultrasound and histopathology examination of pancreatic tissues at the study endpoint. The study has been completed, data reported to CAPR Oversight Committee and CAPR is currently considering a follow up experiment in a different, more clinically relevant, MEN1 murine model.