Combination Treatment With Sorafenib and Everolimus Regresses a Doxorubicin-resistant Osteosarcoma in a PDOX Mouse Model.

BACKGROUND/AIM: Osteosarcoma is a rare but recalcitrant type of bone cancer. To discover an effective therapy for osteosarcoma, we used a patient-derived orthotopic xenograft (PDOX) mouse model. A PDOX mouse model has been established for all major cancer types. Strong synergistic efficacy of sorafenib (SFN) and everolimus (EVL) has been demonstrated in several cancers. In the present study, we examined the efficacy of a SFN and EVL combination on a doxorubicin (DOX)-resistant osteosarcoma PDOX. MATERIALS AND METHODS: The osteosarcoma PDOX models were randomly divided into five treatment groups, each containing six mice: Control; DOX; SFN; EVL; and a combination of SFN and EVL. Mice were treated for 14 days. To observe the efficacy of these treatments, tumor size and body weight were measured, and histological sections were analyzed. RESULTS: Tumor growth regression was observed only in the mice treated with the combination of SFN-EVL. Histological analysis revealed necrosis with degenerative changes in tumors treated with a combination of SFN-EVL. CONCLUSION: A SFN-EVL combination could be a novel effective treatment option for osteosarcoma.

Generation and molecular characterization of pancreatic cancer patient-derived xenografts reveals their heterologous nature.

Pancreatic ductal adenocarcinoma (PDAC) is the most challenging type of cancer to treat, with a 5-year survival rate of <10%. Furthermore, because of the large portion of the inoperable cases, it is difficult to obtain specimens to study the biology of the tumors. Therefore, a patient-derived xenograft (PDX) model is an attractive option for preserving and expanding these tumors for translational research. Here we report the generation and characterization of 20 PDX models of PDAC. The success rate of the initial graft was 74% and most tumors were re-transplantable. Histological analysis of the PDXs and primary tumors revealed a conserved expression pattern of p53 and SMAD4; an exome single nucleotide polymorphism (SNP) array and Comprehensive Cancer Panel showed that PDXs retained over 94% of cancer-associated variants. In addition, Polyphen2 and the Sorting Intolerant from Tolerant (SIFT) prediction identified 623 variants among the functional SNPs, highlighting the heterologous nature of pancreatic PDXs; an analysis of 409 tumor suppressor genes and oncogenes in Comprehensive Cancer Panel revealed heterologous cancer gene mutation profiles for each PDX-primary tumor pair. Altogether, we expect these PDX models are a promising platform for screening novel therapeutic agents and diagnostic markers for the detection and eradication of PDAC.