Identification of diterpenoid compounds that interfere with Fli-1 DNA binding to suppress leukemogenesis

Abstract

The ETS transcription factor Fli-1 controls the expression of genes involved in hematopoiesis including cell proliferation, survival, and differentiation. Dysregulation of Fli-1 induces hematopoietic and solid tumors, rendering it an important target for therapeutic intervention. Through high content screens of a library of chemicals isolated from medicinal plants in China for inhibitors of a Fli-1 transcriptional reporter cells, we hereby report the identification of diterpenoid-like compounds that strongly inhibit Fli-1 transcriptional activity. These agents suppressed the growth of erythroleukemic cells by inducing apoptosis and differentiation. They also inhibited survival and proliferation of B-cell leukemic cell lines as well as primary B-cell lymphocytic leukemia (B-CLL) isolated from 7 patients. Moreover, these inhibitors blocked leukemogenesis in a mouse model of erythroleukemia, in which Fli-1 is the driver of tumor initiation. Computational docking analysis revealed that the diterpenoid-like compounds bind with high affinity to nucleotide residues in a pocket near the major groove within the DNA-binding sites of Fli-1. Functional inhibition of Fli-1 by these compounds triggered its further downregulation through miR-145, whose promoter is normally repressed by Fli-1. These results uncover the importance of Fli-1 in leukemogenesis, a Fli-1-miR145 autoregulatory loop and new anti-Fli-1 diterpenoid agents for the treatment of diverse hematological malignancies overexpressing this transcription factor.

Fli-1 Activation through Targeted Promoter Activity Regulation Using a Novel 3’, 5’-diprenylated Chalcone Inhibits Growth and Metastasis of Prostate Cancer Cells

“…Based on this strategy, we hypothesized that C10 might act as an agonist for Fli-1 expression in prostate cancer cells, which was opposite to the role of Fli-1 in other cancers. For example, professor Ben-David's group has found that Fli-1 was a proto-oncogene in leukemia, and inhibiting the expression of Fli-1 could inhibit the proliferation of leukemia cells and induce apoptosis [23]. Therefore, interestingly, we focused on the opposite conclusion and want to investigate the molecular mechanism.…”

Single cell characterization of B-lymphoid differentiation and leukemic cell states during chemotherapy in ETV6-RUNX1 positive pediatric leukemia identifies drug-targetable transcription factor activities

“…We tested small molecule drugs targeting the ETS-factors ELK3, or ERG and FLI1 in dexamethasone resistant E/R+ REH cells and found reduced cell viability with sub-micromolar concentration. Inhibitors abrogating FLI1, MEF2C, ELK3, or SP4 activation have been previously shown to have efficacy in different cancers [94][95][96][97][98][99]. Moreover, the small molecule ERG/FLI1 inhibitor tested here has entered a phase 1 study in Ewing sarcoma [100].…”

FLI1 promotes protein translation via the transcriptional regulation of MKNK1 expression

“…Thus, the therapeutic targeting of FLI1 is an attractive strategy. Accordingly, several classes of compounds with a potent anti-FLI1 activity have recently been identified (18)(19)(20)(21)(22). Among these, two flavagline-like compounds exhibiting potent FLI1 inhibition were also identified (22).…”

“…To clone the MKNK1 promoter, various regions of the MKNK1 promoter (for details please see Fig. 2B) were isolated by qPCR (the list of primers is presented in Table SI) and cloned into the luciferase reporter vector PGL3 (Promega), as previously described (21). These promoter vectors (1 µg) with either MigR1 (1 µg) or MigR1-FLI1 (1 µg) were transfected into 293T cells (ATCC-CRL-3216) using Lipofectamine 2000 (Life Technologies; Thermo Fisher Scientific) following the manufacturer's protocol.…”

“…Renilla luciferase was used in transfection as an internal control to examine the transfection efficiency, according to the manufacturer's recommendations (Promega). The transfected cells were then plated 8x10 3 cells/well into 96-well plates and luciferase activity was determined, as previously described (21).…”