Athymic nude nu nu mice

Kras^LSL-G12D/+ mice^{46 (link)} were a gift from T. Jacks (Massachusetts Institute of Technology). Trp53^Flox/Flox mice^{47 (link)} were a gift from A. Berns (The Netherlands Cancer Institute). Adenovirus expressing Cre recombinase was injected into the hind limb of KP mice^{18 (link)}. Once the primary tumors reached around 250 mm³, the tumor-bearing legs were amputated and the mice were further followed for the development of lung metastases^{3 (link)}. Male (n=7) and female (n=7) mice were included for RNA-sequencing. Paired primary and lung metastases that were used for RNA sequencing were developed from 5 male and 2 female mice. Both male (n=35) and female (n=17) mice that developed primary sarcomas were chosen for qPCR validation of Neat1 expression in primary tumors and lung metastases. Lung metastasis developed in 18 male and 5 female mice. 17 male and 12 female mice did not develop lung metastasis and were euthanized. Athymic nude (nu/nu) mice (5 to 6 weeks old) for the transplant study were purchased from Taconic Biosciences and maintained in Duke University’s accredited animal facility. All animal studies were performed in accordance with protocols approved by the Duke University Institutional Animal Care and Use Committee (IACUC).