Abstract 4823: Characterization of newly established WM-1-SNU cell line harboring negative for MYD88 L265P derived from Waldenstrom macroglobulinemia patient's peripheral blood using xenograft model
Authors: Park Hyejoo , Koh Youngil , Ahn Kwang-Sung , Kim Hyo Jung , Yoon Sung-Soo 
Published: July 2017

Abstract
Waldenstrom macroglobulinemia (WM) is a rare hematologic malignancy that is a lymphoplasmacytic lymphoma a type of B-cell disease. The common characteristics of WM cells are expression of B cell markers, CD19 and CD20 and secretion of monoclonal immunoglobulin (Ig) M. The other critical feature of WM is MYD88 L265P that is found almost 90% patients. MYD88 gene is related with immune response and inflammatory signaling. Many researches are underway about MYD88 L265P role in WM. However, there is a lack of functional studies in the negative for MYD88 L265P in WM due to the absence of the MYD88 L265P negative cell line. Each cell lines represent the heterogeneity and molecular diversity by genetic features, it is important to establish the MYD88 L265P negative WM cell line for elucidating the biological characteristics of WM. Mononuclear cells obtained from patient’s peripheral blood by ficoll separation and were injected to NRG (JAX, USA) mouse via tail vein. After 24 days, mouse sacrificed and extracted bone marrow (BM) cells from mouse tibia by syringe flushing. Mouse BM cells were cultured in Iscove's Modified Dulbecco's Medium (IMDM) supplemented with 20% heat-inactivated FBS, Penicillin-Streptomycin (10,000 U/mL) (Gibco, USA). G-banding was used to confirm the human chromosomes. Sanger sequencing conducted for detecting the MYD88 L265P mutation. Flow cytometry was used for screening cell surface markers and ELISA was used for the detection of immunoglobulin level. For confirm the tumorigenicity of the cell line, we re-injected the cell line to NSG (JAX, USA) mouse by subcutaneously. After 3 weeks, tumor mass and metastatic tissues were cultured in conditioned medium. Tumor cells have had adherent phenotype and human chromosomes were identified by G-banding. MYD88 L265P mutation that genetic signature of WM was not detected both patient’s peripheral blood and established cell line. CD19 and CD20 expressions were not detected, but CD138 highly expression was confirmed about 90%. Lambda and Kappa secretion were not detected in cell culture supernatant. We confirmed the tumorigenicity through re-injection the cell line by subcutaneously. Tumor mass was formed with a 100% probability and metastasis to lung and bone marrow occurred in about 66%. Tumor mass and metastatic tissues were cultured in in vitro and confirmed the reproducibility. In this study, we describe the newly established human WM cell line derived from peripheral blood of the WM patient who negative for MYD88 L265P using xenograft model having unique biological characteristics comparing to MYD88 L265P positive cells that high tumor formation ability and high expression of CD138 and does not secrete IgM.
Citation Format: Hyejoo Park, Youngil Koh, Kwang-Sung Ahn, Hyo Jung Kim, Sung-Soo Yoon. Characterization of newly established WM-1-SNU cell line harboring negative for MYD88 L265P derived from Waldenstrom macroglobulinemia patient's peripheral blood using xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4823. doi:10.1158/1538-7445.AM2017-4823