G007-LK Tankyrase 1/2 Inhibitor: Precision Tool for Wnt/β-catenin Research

Executive Summary: G007-LK is a potent and selective small-molecule inhibitor of tankyrase 1 (TNKS1) and tankyrase 2 (TNKS2), with IC₅₀ values of 46 nM and 25 nM, respectively, measured in biochemical assays (APExBIO). It robustly suppresses Wnt/β-catenin signaling in cell-based systems, such as Wnt3a-induced HEK 293 cells (IC₅₀ = 0.05 μM), and induces β-catenin degradation in APC-mutant colorectal cancer models (Jia et al. 2017). In vivo, G007-LK reduces tumor growth in COLO-320DM xenograft mouse models (dosed at 20–40 mg/kg) and stabilizes AXIN1/2, thereby suppressing oncogenic signaling (DOI). The compound is supplied as a solid with high solubility in DMSO and is recommended for short-term solution use at -20°C (APExBIO).

Biological Rationale

Tankyrase 1 and 2 (TNKS1/2) are members of the poly(ADP-ribosyl) polymerase (PARP) family. They regulate multiple cellular processes, including Wnt/β-catenin signaling, telomere maintenance, and cell cycle progression (Jia et al. 2017). In the canonical Wnt pathway, tankyrases mediate poly(ADP-ribosyl)ation and subsequent proteasomal degradation of AXIN1/2, key negative regulators of β-catenin. Inhibiting tankyrase activity stabilizes AXIN1/2, promotes β-catenin degradation, and attenuates Wnt-driven transcription. Dysregulated Wnt/β-catenin signaling is implicated in colorectal cancer, especially in contexts of APC gene mutation. Tankyrase expression is elevated in several cancer types, including hepatocellular carcinoma and colorectal tumors (Jia et al. 2017).

Mechanism of Action of G007-LK tankyrase 1/2 inhibitor

G007-LK is a small molecule that binds to the catalytic domains of TNKS1 and TNKS2. It inhibits auto-poly(ADP ribosyl)ation and substrate modification with nanomolar potency (IC₅₀ = 46 nM for TNKS1; 25 nM for TNKS2) (APExBIO). By blocking tankyrase activity, G007-LK prevents degradation of AXIN1/2, leading to assembly of degradasomes containing phosphorylated β-catenin, β-TrCP, and ubiquitin. This process reduces both cytosolic and nuclear β-catenin levels, thereby inhibiting downstream Wnt signaling (see also: G007-LK as a precise Wnt/β-catenin tool). G007-LK also indirectly modulates Hippo pathway signaling by stabilizing AMOTL1 and AMOTL2, negative regulators of YAP/TAZ, further restraining oncogenic growth (Jia et al. 2017).

Evidence & Benchmarks

• G007-LK inhibits tankyrase auto-poly(ADP ribosyl)ation with IC₅₀ values of 46 nM (TNKS1) and 25 nM (TNKS2) in biochemical enzyme assays (APExBIO).
• In Wnt3a-stimulated HEK 293 cells, G007-LK inhibits the ST-Luc Wnt signaling reporter with an IC₅₀ of 0.05 μM (APExBIO).
• In APC-mutant colorectal cancer cell lines (e.g., SW480), G007-LK induces formation of degradasomes and reduces cytosolic/nuclear β-catenin, as shown by Western blot and immunofluorescence (Jia et al. 2017, Fig. 3).
• G007-LK demonstrates dose-dependent tumor growth inhibition in COLO-320DM xenograft mouse models at 20–40 mg/kg (once daily, oral gavage, 21 days), reducing both TNKS1/2 and β-catenin protein levels and stabilizing AXIN1/2 (Jia et al. 2017, Table 2).
• G007-LK, when combined with MEK or AKT inhibitors, synergistically suppresses proliferation in hepatocellular carcinoma cells (Jia et al. 2017, Fig. 6).
• Tankyrase inhibition by G007-LK upregulates AMOTL1/2, leading to YAP/TAZ downregulation and reduced YAP/TEAD transcriptional activity (Jia et al. 2017, Fig. 4).

This article updates and extends previous overviews by integrating new quantitative in vivo data and clarifying the cross-talk between Wnt and Hippo pathways in cancer biology.

Applications, Limits & Misconceptions

G007-LK is used in basic and translational research to modulate Wnt/β-catenin signaling, study tankyrase biology, and model APC mutation-driven cancers, especially colorectal cancer (see also: in-depth mechanism review). The compound is suitable for cell-based assays (e.g., viability, proliferation, reporter activity), in vivo tumor models, and studies exploring Hippo/YAP pathway interactions. It is not approved for human therapeutic use and should be handled as a research reagent only.

Common Pitfalls or Misconceptions

• G007-LK is not a general PARP inhibitor: It selectively targets TNKS1/2 and does not block classical PARP1/2 activity.
• Not active in water/ethanol: G007-LK is insoluble in water and ethanol; DMSO is required for stock solutions (≥26.5 mg/mL).
• Does not rescue Wnt-inactive cells: In cell lines lacking active Wnt signaling or tankyrase expression, G007-LK has limited effect.
• Not a direct YAP/TEAD inhibitor: YAP pathway modulation is secondary via AMOTL1/2 stabilization, not by direct YAP binding.
• Short-term solution stability: G007-LK should be used in solution only for short durations and stored at -20°C to preserve activity (APExBIO).

This article clarifies boundaries not emphasized in previous summaries such as best-practice laboratory guides, by explicitly noting the limits of solubility and target specificity.

Workflow Integration & Parameters

For in vitro studies, G007-LK should be dissolved in DMSO at concentrations up to 26.5 mg/mL. Typical working concentrations in cell culture range from 10 nM to 1 μM, depending on cell type and pathway activation status. In vivo, published studies report efficacy at 20–40 mg/kg, administered by oral gavage once daily for 2–3 weeks in murine xenograft models (Jia et al. 2017). The compound is supplied as a solid, molecular weight 529.96, chemical formula C₂₅H₁₆ClN₇O₃S. Storage at -20°C is recommended for both powder and short-term stock solutions. APExBIO provides detailed product documentation and batch-specific certificates (G007-LK tankyrase 1/2 inhibitor).

Conclusion & Outlook

G007-LK (SKU B5830) is a validated, high-potency, and highly selective inhibitor of tankyrase 1/2, supporting mechanistic and translational research in Wnt/β-catenin and Hippo pathway modulation. Its robust activity in APC-mutant colorectal cancer and hepatocellular carcinoma models demonstrates its value for cancer biology and drug discovery workflows. Researchers should use G007-LK in accordance with solubility and storage guidelines and recognize its pathway and target specificity. For more information, refer to the APExBIO product page.