Telomeric G4s ligand 2

Telomeric G4s ligand 2 is an orally active and selective telomeric G-quadruplex (G4) ligand, with an IC50 of 0.4 μM. It binds to dimeric telomeric G4 structures, inhibiting the helicase activity of DHX36 and BLM. The compound activates the cGAS-STING and TERRA-ZBP1 pathways, inducing autophagy and G2/M phase cell cycle arrest, and exhibits antiproliferative effects in various cancer cell lines. Telomeric G4s ligand 2 is applicable in colorectal cancer research.

Telomeric G4s ligand 2 (CA11) selectively binds to the dimeric telomeric G-quadruplex HTG57 with a dissociation constant (K d) of 5.8 μM. When used at 1 μM and allowed to equilibrate for 2 minutes, this ligand exhibits high-affinity binding to dimeric telomeric DNA and RNA G4s, with dissociation constants of 0.4 μM and 0.1 μM, respectively. Incubation of Telomeric G4s ligand 2 at concentrations ranging from 0 to 50 μM for 30 minutes at 37°C inhibits the binding of G4 helicases DHX36 and BLM to telomeric G4, achieving maximum inhibition rates of 80% and 50% at 50 μM, respectively. Additionally, at concentrations from 0 to 25 μM, it effectively inhibits telomeric G4 DNA unwinding mediated by complementary antisense strands, reaching a 90% inhibition rate at 25 μM. Telomeric G4s ligand 2 also demonstrates potent inhibition of HCT116 colorectal cancer cell proliferation, with an IC 50 of 0.4 μM. In a dose-dependent manner, concentrations of 0.25 to 0.5 μM over 48 hours induce telomere-specific DNA damage and dysfunction in HCT116 and U2OS cancer cells, activating dual innate immune sensors. It induces autophagy via the TERRA-ZBP1 and cGAS-STING pathways. Furthermore, at 0 to 100 nM over 9 days, Telomeric G4s ligand 2 effectively suppresses long-term clonogenic formation in U2OS, MC38, HCT116, and HeLa cancer cells.

The telomeric G4s ligand 2 [administered via gavage every other day for 26 days at a dose of 20-40 mg/kg] effectively inhibits the growth of MC38 colorectal tumors in mice, activates antitumor immunity, and is well-tolerated systemically.