Abstract 390: A comparison of the activity of the quadruplex-targeting experimental drugs QN-302 and CX-5461 (pidnarulex) in wild-type and gemcitabine-resistant pancreatic cancer cell lines

Abstract

Abstract The compound QN-302, a tetra-substituted naphthalene diimide (ND) derivative has been designed as a potent compound for targeting quadruplex sequences in cancer genes. It has single-digit nM anti-proliferative activity in a panel of human pancreatic cancer (PDAC) cell lines (Ahmed et al., ACS Med Chem Lett, 2020, 11, 1634-1644). It also has significant anti-tumor activity in xenograft, orthotopic and genetic (KPC) models for PDAC. Its mode of action involves the targeting of quadruplex (G4)-forming sites in promoter regions of cancer-associated genes, where their prevalence is over-represented compared to other genes. The structurally unrelated compound CX-5461 has also been reported to be a G4-binding agent, with selective activity in BRCA1/2 deficient cells and tumors (Xu and Hurley, Bioorg Med Chem Lett. 2022; Xu et al., Nat Commun, 2017). It is currently in early-stage clinical trials in breast and other solid cancers with deficiencies in DNA repair (Hilton et al., Nat Commun. 2022). We have previously reported that a precursor to QN-302, the tri-substituted naphthalene diimide compound CM03, is highly active in both wild-type and gemcitabine-resistant PDAC cell lines (Ahmed et al, Sci Rep, 2020). This is explained by the finding using whole-genome transcriptome analysis that the CM03-sensitive genes are largely unaffected in the resistant lines. We now report that the clinical candidate compound QN-302, which is 10-fold more potent than CM03, retains its potency in both MIA-PACA2 and PANC-1 PDAC cell lines with >1000-fold increase in gemcitabine resistance. This is also the case for CX-5461, although this compound is 50-100 times less potent, with GI50 values of 83-95 nM in cell proliferation assays treated for 96 h. Gemcitabine either alone or in combination is still a mainstay of current PDAC treatment. Resistance to gemcitabine is common and is a major contributor to the poor outcomes for most PDAC patients. The ability of QN-302 to retain activity in chemo-resistant PDAC cell lines suggests that it will offer significant advantage in the clinic over gemcitabine-based therapies. QN-302 is bio-available at therapeutic doses and is well tolerated at these levels in animal models. It is being developed for clinical evaluation by Qualigen Therapeutics Inc and is currently at the pre-IND stage. Citation Format: Ahmed Ahmed, Tariq Arshad, Stephen Neidle. A comparison of the activity of the quadruplex-targeting experimental drugs QN-302 and CX-5461 (pidnarulex) in wild-type and gemcitabine-resistant pancreatic cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 390.