Inhibition of BCR signaling using the Syk inhibitor TAK-659 prevents stroma-mediated signaling in chronic lymphocytic leukemia cells

Abstract

Proliferation and survival of chronic lymphocytic leukemia (CLL) cells depend on microenvironmental signals coming from lymphoid organs. One of the key players involved in the crosstalk between CLL cells and the microenvironment is the B-cell receptor (BCR). Syk protein, a tyrosine kinase essential for BCR signaling, is therefore a rational candidate for targeted therapy in CLL. Against this background, we tested the efficacy of the highly specific Syk inhibitor TAK-659 in suppressing the favorable signaling derived from the microenvironment. To ex vivo mimic the microenvironment found in the proliferation centers, we co-cultured primary CLL cells with BM stromal cells (BMSC), CD40L and CpG ODN along with BCR stimulation. In this setting, TAK-659 inhibited the microenvironment-induced activation of Syk and downstream signaling molecules, without inhibiting the protein homologue ZAP-70 in T cells. Importantly, the pro-survival, proliferative, chemoresistant and activation effects promoted by the microenvironment were abrogated by TAK-659, which furthermore blocked CLL cell migration toward BMSC, CXCL12, and CXCL13. Combination of TAK-659 with other BCR inhibitors showed synergistic effect in inducing apoptosis, and the sequential addition of TAK-659 in ibrutinib-treated CLL cells induced significantly higher cytotoxicity. These findings provide a strong rationale for the clinical development of TAK-659 in CLL.

Microenvironment regulates the expression of miR-21 and tumor suppressor genes PTEN, PIAS3 and PDCD4 through ZAP-70 in chronic lymphocytic leukemia

“…Using this approach we observed an increase in survival, proliferation and chemoresistance in primary CLL cells. Interestingly, the co-culture also induced activation and modulation of expression of different molecules, including increased expression of ZAP-70 7 and phosphorylation of ERK1/2 and STAT3 22 . Since we observed the involvement of the ZAP-70-ERK1/2-STAT3 axis in the induction of miR-21 expression in Ramos cells, we co-cultured primary CLL cells from 40 patients and observed a relative mean increase of 2.57 fold of miR-21 expression after 48 hours compared to the expression observed in cells kept in suspension (from 7.921 AU ± 1.091 to 20.35 AU ± 1.938; p < 0.0001) (Fig.…”

Phase I Study of TAK-659, an Investigational, Dual SYK/FLT3 Inhibitor, in Patients with B-Cell Lymphoma

“…The estimated sample sizes for the DLBCL and iNHL expansion cohorts were based on a Simon 2-stage design using the following parameters: a 1-sided test at the significance level of =0.1, a power of 80%, a null hypothesis of an ORR of ≤20% for DLBCL and ≤35% for iNHL, and an alternative hypothesis of an ORR of ≥40% for DLBCL and ≥60% for iNHL. A total of 12-25 DLBCL patients (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) patients projected based on a 15% dropout rate) and 10-23 iNHL patients (14-27 patients projected based on a 15% dropout rate) would be needed for the expansion cohorts.…”

“…TAK-659 is an investigational, oral, reversible, and potent dual inhibitor of SYK and FMS-like tyrosine kinase 3 (FLT3) (16). TAK-659 has demonstrated inhibitory activity in preclinical models of diffuse large B-cell lymphoma (DLBCL), in a RL follicular lymphoma (FL) cell line (17), and in chronic lymphocytic leukemia (CLL) cells (18). Preclinical studies in multiple syngeneic or xenograft models have also shown that TAK-659 administration can result in reductions in immunosuppressive cell populations, such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells, which are mediated by both SYK and FLT3 signaling (19), suggesting an immune-modulating effect (20, 21 Based on these preclinical data, we conducted a first-in-human study of TAK-659 to determine the safety, tolerability, and maximum tolerated dose (MTD)/recommended phase II dose (RP2D) of TAK-659 in patients with solid tumors and B-cell lymphomas.…”

Syk inhibitors in clinical development for hematological malignancies

“…Combination of TAK-659 with other BCR inhibitors showed synergistic effect in inducing apoptosis. Combination of TAK-659 and ibrutinib induced significantly higher cytotoxicity toward CLL cells [ 84 ].…”