Discovery of Novel Inhibitor for WNT/β-Catenin Pathway by Tankyrase 1/2 Structure-Based Virtual Screening

Abstract

Aberrant activation of the WNT/β-catenin signaling pathway is implicated in various types of cancers. Inhibitors targeting the Wnt signaling pathway are intensively studied in the current cancer research field, the outcomes of which remain to be determined. In this study, we have attempted to discover novel potent WNT/β-catenin pathway inhibitors through tankyrase 1/2 structure-based virtual screening. After screening more than 13.4 million compounds through molecular docking, we experimentally verified one compound, LZZ-02, as the most potent inhibitor out of 11 structurally representative top hits. LiCl-induced HEK293 cells containing TOPFlash reporter showed that LZZ-02 inhibited the transcriptional activity of β-catenin with an IC50 of 10 ± 1.2 μM. Mechanistically, LZZ-02 degrades the expression of β-catenin by stabilizing axin 2, thereby diminishing downstream proteins levels, including c-Myc and cyclin D1. LZZ-02 also inhibits the growth of colonic carcinoma cell harboring constitutively active β-catenin. More importantly, LZZ-02 effectively shrinks tumor xenograft derived from colonic cell lines. Our study successfully identified a novel tankyrase 1/2 inhibitor and shed light on a novel strategy for developing inhibitors targeting the WNT/β-catenin signaling axis.

Targeting the Wnt/β-catenin signaling pathway in cancer

“…A decreased nuclear β-catenin level predicted for apoptosis suggesting the tankyrase inhibitor could overcome resistance to AKT and PI3K inhibitors [61]. The same antineoplastic effect was observed in LZZ-02, a novel Tankyrase 1/2 inhibitor [69]. Concerns of gastrointestinal toxicity have been noted in analysis of these inhibitors, and further studies are needed [70].…”

Tankyrases as modulators of pro-tumoral functions: molecular insights and therapeutic opportunities

“…The nicotinamide subsite is highly conserved among the PARP family while the adenosine subsite is more specific of tankyrases. This fact allows those inhibitors that target adenosine subsite present high selectivity towards TNKS [ 102 , 116 ]. In the next section we will update the information about the role of tankyrases in cancer as well as the recent approaches using TNKS inhibitors as single and combined antitumor therapies.…”

“…LZZ-02 blockades the proliferation of APC mutated SW480 and DLD1 cells through the inhibition of the Wnt/β-catenin signaling. In addition, this inhibitor showed a robust antitumor effect in a DLD1-derived colon tumor xenograft model, pointing out the promising therapeutic application [ 116 ].…”

“…However, a recent report proved that long-type truncated APC mutation cells are also sensitive to TNKS inhibitors [ 92 , 93 ]. In fact, the recently discovered TNKS inhibitor LZZ-02 has shown a potent therapeutic effect in a xenograft model derived from the DLD-1 colon cells [ 116 ]. All this information points out the need to get representative genetic models to define the genetic context, understand the molecular mechanism of a signaling pathway as well as achieve an accurate and effective treatment.…”

“…Weight loss and general toxicity were not observed at moderate dosage, although modest levels of intestinal toxicity were appreciated at high dosage, pointing out the unavoidable intestinal toxicity of TNKS inhibitors at high doses suggested by Zhong and collaborators [ 13 , 115 ]. On the other hand, LZZ-02 was shown to have a potent antitumor effect as well as an extraordinary in vivo toxicity profile without body weight loss, which indicates that the inhibitor was well tolerated by mice [ 116 ]. These new inhibitors could become an effective cancer treatment, although the molecular mechanism requires additional investigation together with a better characterization in clinic.…”