CRISPR/Cas9 genome editing in melanoma cells: new insight of RUNT domain

Incidence of melanoma has increased considerably in Western population in consequence of lifestyle and environmental changes. The mortality rate is very high as it is highly invasive and also genetically resistant to chemotherapeutic treatments. It has been reported that mutation rate and gene modulation in melanoma are higher than in other solid malignancies. In addition, transcription factors by acting on gene expression can affect cellular process. In particular, a higher expression of RUNX2 in melanoma than in normal melanocytes have been shown. RUNX2 is the master gene of the osteogenic commitment of MSC, and it is overexpressed in several tumor tissues, including pancreatic cancer, breast cancer, ovarian epithelial cancer, prostate cancer, lung cancer and osteosarcoma. As no direct RUNX2 inhibitor is available and experiments performed with RNA interference were scarcely reproducible, we applied CRISPR/Cas9 technology, that avoid several of the pitfalls associated with interfering RNA, to knockout the RUNT domain of RUNX2 in melanoma cell line. CRISPR/Cas9 technology could delete, partially, the RUNT domain. The deleted clone showed a reduced proliferation, epithelial-mesenchymal transition features and migration ability, suggesting the involvement of RUNT in different pathways of melanoma. In addition, the deleted clone showed a reduction of genes involved in migration ability and an increased expression of SSBP1 gene proposing RUNT as an oncotarget in melanoma.