A four-arm study of A375 melanoma cell line-derived xenograft tumors in NSG mice treated with Vemurafenib and CB839

Melanoma is a rare but deadly form of skin cancer, which is often treated with BRAF inhibitors such as Vemurafenib (referred to as PLX4032). Whilst Vemurafenib prolongs the survival of patients, BRAF inhibitor resistance inevitably occurs in most cases. Previous studies demonstrated that metabolic rewiring occurs in BRAF inhibitor resistance and causes dependence on glutamine. To investigate whether this vulnerability could be exploited with clinically relevant drugs, we used the BRAF inhibitor, Vemurafenib, and the glutaminase imhibitor, CB839 to treat A375-derived melanoma xenografted tumors. We showed that whilst CB839 did not significantly affect the growth of A375-derived tumors compared to those given a vehicle, the addition of CB839 to Vemurafenib treatment had a significant anti-tumor effect. Tumors were taken at the endpoint (Max tumor length 15mm) from the 6 mice in each treatment group and cut into fragments and stored in RNAlater for RNAseq analysis. RNA extraction was performed on 1-3 fragments per tumor to make up 200-300mg of tissue.