Activating mutations in the neuroblastoma rat sarcoma viral oncogene homolog (NRAS) gene are common genetic events in malignant melanoma being found in 15–25% of cases. NRAS is thought to activate ...both mitogen activated protein kinase (MAPK) and PI3K signaling in melanoma cells. We studied the influence of different components on the MAP/extracellular signal-regulated (ERK) kinase (MEK) and PI3K/mammalian target of rapamycin (mTOR)-signaling cascade in NRAS mutant melanoma cells. In general, these cells were more sensitive to MEK inhibition compared with inhibition in the PI3K/mTOR cascade. Combined targeting of MEK and PI3K was superior to MEK and mTOR ₁,₂ inhibition in all NRAS mutant melanoma cell lines tested, suggesting that PI3K signaling is more important for cell survival in NRAS mutant melanoma when MEK is inhibited. However, targeting of PI3K/mTOR ₁,₂ in combination with MEK inhibitors is necessary to effectively abolish growth of NRAS mutant melanoma cells in vitro and regress xenografted NRAS mutant melanoma. Furthermore, we showed that MEK and PI3K/mTOR ₁,₂ inhibition is synergistic. Expression analysis confirms that combined MEK and PI3K/mTOR ₁,₂ inhibition predominantly influences genes in the rat sarcoma (RAS) pathway and growth factor receptor pathways, which signal through MEK/ERK and PI3K/mTOR, respectively. Our results suggest that combined targeting of the MEK/ERK and PI3K/mTOR pathways has antitumor activity and might serve as a therapeutic option in the treatment of NRAS mutant melanoma, for which there are currently no effective therapies.
Background BRAF inhibitor (BRAFi) and MEK inhibitor (MEKi) frequently cause cutaneous adverse events. Objective We sought to investigate the cutaneous safety profile of BRAFi versus BRAFi and MEKi ...combination regimens. Methods We performed a retrospective cohort study, collecting data from 44 patients with melanoma treated either with BRAFi (vemurafenib or dabrafenib) or BRAFi and MEKi combination regimens (vemurafenib + cobimetinib or dabrafenib + trametinib). Patient characteristics, and the occurrence and severity of cutaneous adverse events, are described. Results The development of cutaneous adverse events was significantly less frequent ( P = .012) and occurred after longer treatment time ( P = .025) in patients treated with BRAFi and MEKi combination regimen compared with patients treated with BRAFi monotherapy. Among patients who received both BRAFi and the combination of BRAFi and MEKi at different time points during their treatment course, the development of squamous cell carcinoma or keratoacanthoma was significantly less frequent when they received the combination regimen ( P = .008). Patients receiving vemurafenib developed more cutaneous adverse events ( P = .001) and in particular more photosensitivity ( P = .010) than patients who did not. Limitations There were a limited number of patients. Conclusion Combination regimen with BRAFi and MEKi shows fewer cutaneous adverse events and longer cutaneous adverse event-free interval compared with BRAFi monotherapy.
Recent advances in uveal melanoma treatment Álvarez‐Rodríguez, Beatriz; Latorre, Alfonso; Posch, Christian ...
Medicinal research reviews,
November 2017, Letnik:
37, Številka:
6
Journal Article
Recenzirano
Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Recent advances in the understanding of molecular characteristics helped to determine which tumors are most likely to ...progress. About 50% of patients carrying genetic alterations such as chromosomal aberrations and mutations are at significant risk for metastatic disease of which the majority will succumb to UM within few months. Currently, there is no effective treatment for metastatic uveal melanoma, and we hope this review will encourage researchers and clinicians to work to find a better standard of care. In this article we provide a comprehensive overview of the molecular framework of UM, highlighting the most common mutations involved in this kind of cancer. It also covers the most recent treatments from basic research to clinical trials, including small molecules, nucleic acids or immunotherapy, among others. It is intended to serve as a key reference for clinicians and researchers working in this field.
Immune checkpoint inhibition (ICI) improves outcomes in melanoma patients, but associated T-cell activation frequently leads to immune-related cutaneous adverse events (cutAEs). To dynamically ...identify T-cell subtypes and immune signatures associated with cutAEs, a pilot study was performed in stage III-IV melanoma patients using blood samples for flow cytometry and cytokine analysis. Blood samples were taken from patients before initiation of ICI (naive), at the onset of a cutAE, and after 6 months of ICI treatment. Overall, 30 patients were treated either with anti-PD1 monotherapy or with anti-PD-1/anti-CTLA-4 combination therapy. Flow cytometry analysis of PBMCs showed that ICI induced an overall shift from a Th2 towards a Th1 profile. Twelve patients (40%) developed cutAEs, which were associated with increased Th22 cells and Th17 cells, supported by a tendency to have elevated Th17/Th22-associated cytokines such as IL-17A, IL-22 and IL-23 levels in the plasma. Cytokine signatures specific for urticaria and T-cell-mediated cutAEs were identified in the plasma of patients by a bead-based assay. IL-10 was elevated in non-responders and, interestingly, during cutAEs. In conclusion, we identified distinct immune signatures based on the Th17/Th22 pathway in cutAEs, both in PBMCs and plasma. In addition, our finding of upregulated IL-10 during cutAEs supports the notion of treating these patients early and adequately to avoid implications for the overall outcome.
PDF
