Melanoma is the most aggressive and deadly form of skin cancer with increasing case numbers worldwide.,The development of inhibitors targeting mutated BRAF (found in around 60% of melanoma patients) has markedly improved overall survival of patients with late-stage tumors, even more so when combined with MEK inhibitors targeting the same signaling pathway.,However, invariably patients become resistant to this targeted therapy resulting in rapid progression with treatment-refractory disease.,The purpose of this study was the identification of new kinase inhibitors that do not lead to the development of resistance in combination with BRAF inhibitors (BRAFi), or that could be of clinical benefit as a 2nd line treatment for late-stage melanoma patients that have already developed resistance.,We have screened a 274-compound kinase inhibitor library in 3 BRAF mutant melanoma cell lines (each one sensitive or made resistant to 2 distinct BRAFi).,The screening results were validated by dose-response studies and confirmed the killing efficacies of many kinase inhibitors.,Two different tools were applied to investigate and quantify potential synergistic effects of drug combinations: the Chou-Talalay method and the Synergyfinder application.,In order to exclude that resistance to the new treatments might occur at later time points, synergistic combinations were administered to fluorescently labelled parental and resistant cells over a period of > 10 weeks.,Eight inhibitors targeting Wee1, Checkpoint kinase 1/2, Aurora kinase, MEK, Polo-like kinase, PI3K and Focal adhesion kinase killed melanoma cells synergistically when combined with a BRAFi.,Additionally, combination of a Wee1 and Chk inhibitor showed synergistic killing effects not only on sensitive cell lines, but also on intrinsically BRAFi- and treatment induced-resistant melanoma cells.,First in vivo studies confirmed these observations.,Interestingly, continuous treatment with several of these drugs, alone or in combination, did not lead to emergence of resistance.,Here, we have identified new, previously unexplored (in the framework of BRAFi resistance) inhibitors that have an effect not only on sensitive but also on BRAFi-resistant cells.,These promising combinations together with the new immunotherapies could be an important step towards improved 1st and 2nd line treatments for late-stage melanoma patients.,The online version of this article (10.1186/s13046-019-1038-x) contains supplementary material, which is available to authorized users.
Germline mutations in BAP1 have been associated with BAP1-Tumor Predisposition Syndrome (BAP1-TPDS), a predisposition to multiple tumors within a family that includes uveal melanoma (UM), cutaneous melanoma, malignant mesothelioma and renal cell carcinoma.,Alternatively, somatic mutations in BAP1 in UM have been associated with high risk for metastasis.,In this study, we compare the risk of metastasis in UM that carry germline versus somatic BAP1 mutations and mutation-negative tumors.,DNA extracted from 142 UM and matched blood samples was sequenced using Sanger or next generation sequencing to identify BAP1 gene mutations.,Eleven of 142 UM (8%) carried germline BAP1 mutations, 43 (30%) had somatic mutations, and 88 (62%) were mutation-negative.,All BAP1 mutations identified in blood samples were also present in the matched UM.,There were 52 unique mutations in 54 tumors.,All were pathogenic or likely pathogenic.,A comparison of tumors carrying somatic vs. germline mutations, or no mutations, showed a higher frequency of metastasis in tumors carrying somatic mutations: 74% vs.,36%, P=0.03 and 74% vs.,26% P<0.001, respectively.,Tumors with a somatic mutation compared to mutation-negative had an older age of diagnosis of (61.8 vs.,52.2 years, P=0.002), and shorter time to metastasis (16 vs. 26 months, P=0.04).,Kaplan-Meier analysis further showed that tumors with somatic (vs. germline) mutations demonstrated a greater metastatic risk (P=0.03).,Cox multivariate analysis showed in addition to chromosome-3 monosomy and larger tumor diameter, the presence of BAP1 somatic, but not germline mutations, was significantly associated with risk of metastasis(P=0.02).,Personal or family history of BAP1-TPDS was available for 79 of the cases.,All eight cases with germline mutations reported a history of BAP1-TPDS, which was significantly greater than what was observed in cases with somatic mutations (10 of 23, P=0.009) or mutation-negative cases (11 of 48, P<0.001).,Defining germline vs. somatic nature of BAP1 mutations in UM can inform the individual about both the risk of metastasis, and the time to metastasis, which are critically important outcomes for the individual.,This information can also change the cascade screening and surveillance of family members.,The online version of this article (10.1186/s12885-018-5079-x) contains supplementary material, which is available to authorized users.