Directed therapy for patients with myelodysplastic syndromes (MDS) by suppression of cyclin D1 with ON 01910.Na

Abstract

Background: We previously demonstrated upregulation of c-myc, survivin, and cyclin D1 in CD34+ bone marrow mononuclear cells (BMMNCs) of patients with trisomy 8 and monosomy 7 myelodysplastic syndromes (MDS). "Knockdown" of cyclin D1 by RNA interference decreased trisomy 8 cell growth, suggesting that this might be a therapeutic target in MDS.

Experimental design: We performed preclinical studies using BMMNCs from patients with MDS and AML to examine the effects of the styryl sulfone ON 01910.Na on cyclin D1 accumulation, aneuploidy, and CD34+ blast percentage. We next treated twelve patients with higher risk MDS and two trisomy 8 AML patients with ON 01910.Na on a phase I clinical protocol (NCT00533416).

Results: ON 01910.Na inhibited cyclin D1 expression, and was selectively toxic to trisomy 8 cells in vitro. Flow cytometry studies demonstrated increased mature CD15+ myeloid cells and decreased CD34+ blasts. Three patients treated with ON 01910.Na on a clinical had decreased bone marrow blasts by ≥ 50%, and three patients had hematologic improvements, one of which was sustained for 33 months. Patients with hematologic responses to ON 01910.Na had decreased cyclin D1 expression in their CD34+ cells.

Conclusions: The preclinical results and responses of patients on a clinical trial warrant further investigation of ON 01910.Na as a potential novel targeted therapy for higher risk MDS patients.

Conflict of interest statement

Conflict of interest: Onconova Therapeutics provided ON1910.Na and research funding to Dr. Sloand for correlative laboratory experiments. Francois Wilhelm is Chief Medical Officer and Senior Vice President at Onconova Therapeutics Inc.

Published by Elsevier Ltd.

Figures

Figure 1

Effects of ON 01910.Na on CD34+ blasts, CD15+ myeloid cells, and aneuploidy in MDS cells in vitro. BMMNCs from patients with RAEB-1, RAEB-2 were grown in the presence of vehicle or increasing concentrations of ON 01910.Na. The percentage of CD34+ blasts (panel A), CD15+ myeloid cells (panel B) were determined by flow cytometry, and percentages of aneuploid and diploid cells were determined by FISH expressed as a percentage of the total cell population (panel C) as described in Materials and Methods. Individual lines represent independent patient samples. Each data point in panel C represents a mean +/− SEM from 3 replicate determinations.

Figure 2

Clinical trial design.

Figure 3

Relationship of ON 01910.Na administration and peripheral blood counts. Peripheral blood counts of patients receiving ON 1910.Na who demonstrated increased blood counts coincident with administration of drug. Start of each cycle of infusion indicated by arrows. All counts depicted are without growth factor or transfusion support.

Figure 4

Decreasing levels of cyclin D1 in peripheral blood CD34+ cells following administration of ON 1910.Na Cyclin D1 was measured by flow cytometry as described in Materials and Methods in peripheral bood CD34+ cells of patients receiving ON1910. Gating strategy is seen at far left: live CD33+ cells were discriminated from dead cells by a CD33 versus BiViD gate. Mononuclear cells were identified by a forward scatter-area (FSC-A) versus side scatter-area (SSC-A) plot. Viable CD33+ cells were then dichotomized on the basis of maturation by a CD13+ versus CD34+ bivariate plot. Cyclin-D1 positives were then identified by a CD33 versus cyclin-D plot, with positive events for cyclin-D1 defined on the basis of a fluorescence-minus-one (FMO) control. Percentages of CD34+ cells expressing cyclin D1 from three patients are seen in the right panel.