TC14012 inhibits protective effects of CXCL12 and accessory cells. (A) CLL cells were grown on NLCs for 2 weeks and then reseeded on the NLCs (controls; 100% viability) or seeded into wells without NLCs and treated with or without CXCL12 and with CXCL12 and TC14012 (100 μ/mL), as indicated. Presented are the mean ± SEM relative viabilities related to the viabilities of CLL cells remaining on NLCs of 10 experiments with cells from different CLL patients. CLL cells cultured without NLCs or without NLCs in the presence of CXCL12 and TC14012 had significantly reduced viability at each of the indicated time points (^*P < .05). Synthetic CXCL12 partially restores the antiapoptotic effect of NLCs, resulting in a significantly higher viability of CLL cells without NLCs in the presence of synthetic CXCL12 (third block; ^**P < .05) when compared with CLL cells without NLCs (second block). (B) CLL cells were seeded onto M1-10B4 stromal cells with or without TC14012, and cell viability was measured after 24, 48, and 72 hours. Cell viability was related to the viability of M1-10B4 stromal cells (100%). Presented are the mean ± SEM relative viabilities related to the viabilities of CLL cells remaining on M2-10B4 cells of 8 experiments with cells from different patients (^*P < .05).