PB1975: THE RESEARCH ON THE MECHANISM OF RRAD GENE IN MULTIPLE MYELOMA

Background: Multiple myeloma is the second most common hematological malignancy with a high incidence. The pathogenesis of multiple myeloma is still unclear, and specific gene expression abnormalities may play a key role in the pathogenesis of MM.

Aims: The research on the mechanism of RRAD gene in multiple myeloma

Methods: The study collected bone marrow specimens and 9 healthy volunteers from 20 newly diagnosed MM patients admitted to the Affiliated Hospital of Zunyi Medical University from January 2019 to June 2020.The RT-qPCR method was used to detect the transcription level of RRAD in 20 newly diagnosed MM patients, 9 healthy donors and human MM cell lines; RRAD overexpression cell lines were constructed in SKO-007 and H929 by lentivirus infection, and flow cytometry Cytometry, RT-PCR and Western Blot verified the efficiency of overexpression; CCK8 method was used to study the effect of RRAD on cell proliferation; flow cytometry was used to detect cell apoptosis and cycle.Decitabine was used to treat MM cell lines, and RT-qPCR was used to detect changes in RRAD gene expression; CCK8 was used to detect the effect of cell proliferation; flow cytometry was used to detect cell apoptosis and cycle; MSP method was used to detect RRAD methylation of MM cells Level.

Results: Compared with 9 healthy donors, the expression level of RRAD was lower in 20 newly diagnosed MM patients (P = 0.017).Compared with 9 healthy donors, the expression level of RRAD in the MM cell line is low.The ROC curve results show that the expression level of RRAD has a significant diagnostic value for the diagnosis of MM (P <0.001).RRAD gene overexpression can promote MM cell apoptosis and block cell cycle into S phase.DAC can inhibit the proliferation of SKO-007, H929, U266 cells in a dose-dependent manner.Promote the apoptosis of SKO-007, H929, U266 cells, block the cell cycle into S phase or G2 phase and increase the expression of RRAD.After SKO-007, H929, and U266 cells were treated by DAC, the RRAD methylation level of SKO-007 cells decreased, but the RRAD methylation level of H929 and U266 cells did not change significantly.

Summary/Conclusion: 1. RRAD expression in MM is low.2. The expression level of RRAD is closely related to the presence or absence of bone disease, which affects the patient’s quality of life and prognosis assessment.3. The expression level of RRAD has significant diagnostic value for the diagnosis of MM.4. Overexpression of RRAD can block the cell cycle in S phase and promote MM cell apoptosis.5. Hypermethylation of RRAD in MM leads to epigenetic inactivation, which reduces the expression of RRAD and reduces MM Apoptosis of cells loses its anti-tumor effect, which is a new molecular mechanism for the occurrence and development of MM.