Establishment and characterization of a novel vincristine‐resistant diffuse large B‐cell lymphoma cell line containing the 8q24 homogeneously staining region

• Published in: FEBS open bio 2018-12, Vol.8 (12), p.1977-1991
• Main Authors: Mizuno, Shohei, Hanamura, Ichiro, Ota, Akinobu, Karnan, Sivasundaram, Kanasugi, Jo, Nakamura, Ayano, Takasugi, Souichi, Uchino, Kaori, Horio, Tomohiro, Goto, Mineaki, Murakami, Satsuki, Gotou, Mayuko, Yamamoto, Hidesuke, Watarai, Masaya, Shikami, Masato, Hosokawa, Yoshitaka, Miwa, Hiroshi, Taniwaki, Masafumi, Ueda, Ryuzo, Nitta, Masakazu, Takami, Akiyoshi
• Format: Article
• Language: English
• Subjects: Artificial chromosomes; B-cell lymphoma; Blood; Bone marrow; Cell growth; Cell proliferation; Chromosome 8; chromosome 8q24; Cloning; Cyclin D; Deoxyribonucleic acid; diffuse large B‐cell lymphoma; DNA; Fluorescence in situ hybridization; Frameshift mutation; Gene amplification; Gene expression; Genomes; Heterozygosity; homogeneously staining region; Hybridization; Hybridization analysis; Labeling; Leukemia; Loss of heterozygosity; Lymphoma; Morphology; MYC; Myc protein; oncogene amplification; p53 Protein; patient‐derived cell line; TOR protein; Tumors; Vincristine
• ISSN: 2211-5463; 2211-5463
• DOI: 10.1002/2211-5463.12538

Chromosome band 8q24 is the most frequently amplified locus in various types of cancers. MYC has been identified as the primary oncogene at the 8q24 locus, whereas a long noncoding gene, PVT1, which lies adjacent to MYC, has recently emerged as another potential oncogenic regulator at this position. In this study, we established and characterized a novel cell line, AMU‐ML2, from a patient with diffuse large B‐cell lymphoma (DLBCL), displaying homogeneously staining regions at the 8q24 locus. Fluorescence in situ hybridization clearly detected an elevation in MYC copy numbers corresponding to the homogenously staining region. In addition, a comparative genomic hybridization analysis using high‐resolution arrays revealed that the 8q24 amplicon size was 1.4 Mb, containing the entire MYC and PVT1 regions. We also demonstrated a loss of heterozygosity for TP53 at 17p13 in conjunction with a TP53 frameshift mutation. Notably, AMU‐ML2 cells exhibited resistance to vincristine, and cell proliferation was markedly inhibited by MYC‐shRNA‐mediated knockdown. Furthermore, genes involved in cyclin D, mTOR, and Ras signaling were downregulated following MYC knockdown, suggesting that MYC expression was closely associated with tumor cell growth. In conclusion, AMU‐ML2 cells are uniquely characterized by homogenously staining regions at the 8q24 locus, thus providing useful insights into the pathogenesis of DLBCL with 8q24 abnormalities. We established a novel cell line, AMU‐ML2, from a patient with diffuse large B‐cell lymphoma, displaying homogeneously staining regions at the 8q24 locus. The amplicon contained the entire MYC and PVT1 regions. Notably, cell proliferation was markedly inhibited by MYC‐shRNA‐mediated knockdown. Furthermore, genes involved in Cyclin D, mTOR, and Ras signaling were downregulated following MYC knockdown. AMU‐ML2 can provide insights into the pathogenesis of the 8q24 amplicon.