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Abstract 2653: Synthetic, small molecule glycosaminoglycan mimetics induce novel anti-cancer activity through preferential targeting of a growth factor receptor


 Glycosaminoglycans (GAGs), such as heparan sulfate (HS), have been implicated in tumor initiation, progression and metastasis. Earlier we have shown that a defined GAG sequence of six residues, but not four or eight residues, inhibits colorectal cancer stem cells (CSCs) by inducing activation of p38 MAPK. To transform this sequence into a drug-like molecule, we developed a synthetic mimetic of the GAG sequence, labeled as G2.2, which was also found to selectively target CSCs over bulk adherent tumor cells. Unfortunately, G2.2’s oral bioavailability was low. To improve upon its drug-like properties, we pursued a hypothesis-driven analog design to derive three lipid-modified analogs (LMAs). Across a panel of > 15 patient-derived colorectal cancer (CRC) cell lines, which could be stratified according to their clinically-relevant consensus molecular subtypes, LMAs showed enhanced potency while retaining selectivity against CSCs in spheroid inhibition assays. Both G2.2 and LMAs displayed better inhibition of cell lines with mesenchymal phenotypes and metabolic dysregulation. Microarray-based screening against more than a dozen receptor tyrosine kinases led to identification of IGF1R as a potential receptor of the synthetic GAG mimetics. To ascertain these screening results, biophysical studies were performed to clarify preferred soluble and/or cell surface target receptors. In line with microarray results, G2.2 preferentially bound to IGF1R in comparison to its soluble ligand IGF-1. G2.2 also preferred IGF1R as compared to an alternative receptor FGFR1. Further, LMAs bound to IGF1R with improved affinities as compared to parent mimetic G2.2, which could explain anti-CSC inhibition results. Unexpectedly, detailed fluorescence titrations revealed that IGF1R affinity of LMAs is minimally impacted by salt concentration, suggesting that these GAG mimetics utilize non-ionic forces in binding, which support the selectivity of target engagement. Overall, this work proves a powerful proof of concept that synthetic GAG mimetics, such as G2.2 and LMAs, present a unique class of anti-cancer therapeutics with high potential for selective elimination of the tumor initiating subpopulation of CRC cells in patient tumors.
 Citation Format: Connor O'Hara, Shravan Morla, Ravikumar Ongolu, Nirmita Patel, Rio Boothello, Bhaumik Patel, Umesh Desai. Synthetic, small molecule glycosaminoglycan mimetics induce novel anti-cancer activity through preferential targeting of a growth factor receptor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2653.