A Novel Anilinoquinazoline Derivative Inhibits Growth of High-Risk Myeloma Cells In Vivo and Regulates Differentiation of Osteoclasts

Abstract 4076 Purpose: Despite recent advances in the use of newly developed drugs, high-risk multiple myeloma (MM) patients harboring del13q, t(4;14) or del17p revealed significantly shorter survival. To overcome the limitation, we have screened forty synthetic anilinoquinazoline (AQ) derivatives, and found a novel compound, Q15, which significantly inhibited the growth of MM cell lines with high-risk chromosomal abnormalities. The purpose of this study is to examine anti-tumor and anti-osteoclastogenic activities of Q15 and to clarify the possibility of development of new drug effective for high-risk MM and bone diseases. Methods and Results: Forty AQ derivatives were synthesized and screened for anti-proliferative effect on KMS34 cells. Q15 strongly inhibited growth of t(4;14)-positive KMS34 cells and induced apoptosis in much lower concentration (IC 50 =78nM) compared with gefitinib (IC 50 =2500nM), a representative AQ. Q15 also inhibited growth of other MM cell lines harboring high-risk chromosomal abnormalities. It was also found that Q15 did not inhibit intracellular tyrosine phosphorylation induced by EGF, FGF-2, HGF and IL-6, suggesting that Q15 showed anti-tumor activity in a different mechanism from that of gefitinib. In vivo anti-myeloma activity was evaluated by intraperitoneal injection of Q15 into KMS34-bearing lcr/SCID mice. Twenty mg/kg Q15 significantly delayed the tumor growth in these mice. Histopathological examinations revealed apoptosis of MM cells in Q15-treated mice. Growth of colony-forming cells was not suppressed by much higher concentrations (25μ M) of Q15 than IC 50 , suggesting low hematopoietic toxicity of Q15. In pharmacokinetic study using high-performance liquid chromatography (HPLC), the plasma concentration of Q15 in mice reached a maximum (C max =4.5μ M) at 1.5hr after injection, and its half life (T 1/2 ) was 4.5hr. In addition, anti-osteoclastogenic activity was also examined by adding Q15 to M-CSF/RANK ligand-induced osteoclastogenic culture of bone marrow mononuclear cells from C57BL/6JJcl mice. The number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts was reduced in the presence of Q15. Conclusion: Q15, a novel AQ derivative, has anti-MM activity in vivo and is a potentially safe and effective drug for high-risk MM with bone lesions. Disclosures: No relevant conflicts of interest to declare.