• MAPK
• Myeloma
• NRAS
• PI3K/AKT
• siRNA

Multiple myeloma (MM) is a malignancy characterized by the monoclonal proliferation of plasma cells within the bone marrow. Mutations in the KRAS and NRAS genes, particularly at codons 12, 13, and 61, are common and regulate the MAPK and PI3K/AKT/mTOR signaling pathways. Association studies in MM highlight the connection between these mutations and drug resistance or disease progression. However, the specific effects and biological implications of these mutations in MM remain poorly explored. Therefore, this thesis focuses on the role of the NRAS 182 A>G (Q61R) mutation in MM cells.
We inhibited the endogenous mutated gene using siRNA in ARK cells heterozygous for the mutation. The efficiency and specificity of a siRNA panel targeting the NRAS 182 A>G mutation were evaluated. NRAS expression and protein levels of NRAS WT, Q61R, pERK, and pAKT were measured using real-time PCR, Western blot, and flow cytometry. NRAS inhibition resulted in a reduction of pERK, G1 phase cell cycle arrest, and decreased cell proliferation. In the OPM2 cell line, which possesses only one WT allele of NRAS, overexpression analyses were conducted using a stable and inducible system. The overexpression of the NRAS 182 A>G mutation led to increased pERK levels, cell proliferation, and migration. While pAKT was increased in both samples: NRAS 182 A>G and NRAS WT.
The findings suggest that the NRAS mutation induces MAPK activation through ERK, promoting cell proliferation, cell cycle progression, and migration.