Lestaurtinib inhibition of the Jak/STAT signaling pathway in hodgkin lymphoma inhibits proliferation and induces apoptosis

Abstract

Standard cytotoxic chemotherapy for Hodgkin Lymphoma (HL) has changed little in 30 years; the treatment for patients with relapsed or refractory disease remains challenging and novel agents are under development. JAK/STAT constitutive activation plays an important role in the pathogenesis of HL. Lestaurtinib is an orally bioavailable multikinase inhibitor that has recently been shown to inhibit JAK2 in myeloproliferative disorders. The potential role of Lestaurtinib in HL therapy is unknown. We have analyzed the effect of Lestaurtinib treatment in five HL cell lines from refractory patients, L-428, L-1236, L-540, HDML-2 and HD-MY-Z. At 48 h, a dose-dependent cell growth inhibition (23%-66% at 300 nM) and apoptotic increment (10%-64% at 300 nM) were observed. Moreover, Lestaurtinib inhibited JAK2, STAT5 and STAT3 phosphorylation and reduced the mRNA expression of its downstream antiapoptotic target Bcl-xL. In addition, we have analyzed the effect of Lestaurtinib treatment in lymph nodes from four classic HL patients. We observed a decrease in cell viability at 24 hours of treatment in three patients (mean decrease of 27% at 300 nM). Our findings provide, for the first time, a molecular rationale for testing JAK2 inhibitors, specifically Lestaurtinib, in HL patients.

Figure 1. Proliferation (A) and apoptosis (B) analysis after 48 h of Lestaurtinib treatment in L-428, L-1236, L-540, HDLM-2 and HD-MY-Z cell lines.

The data are shown as mean ± SEM of three independent replicates. *p<0.05; **p<0.01; ***p<0.001.

Figure 2. Western blot analysis of JAK2/STAT5 pathway protein levels in L-428, L-1236, L-540, HDLM-2 and HD-MY-Z cells after 1 h of Lestaurtinib treatment at different doses: 30, 100 and 300 nM.

Figure 3. Bcl-xL mRNA analysis after 1 h of Lestaurtinib treatment in L-428, L-1236, L-540, HDLM-2 and HD-MY-Z cell lines.

Figure 4. Analysis of cell viability after 24 h of Lestaurtinib treatment in four lymph nodes from classic HL patients.

A: representative example of population selected for analysis (anexin-negative, CD3−, CD40+, CD30+ and CD95+). B: cell viability after treatment compared to DMSO control. The data are shown as mean ± SEM of two independent replicates. SEM was calculated on the proportion (treated/untreated cells).