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Effect of Covalent TAK1 Inhibitors on the Viability of Pancreatic, Renal and Colon Cancer Cells
Author(s) -
Bernard Faviola,
Singer William D.,
Gurbani Deepak,
Li Tan,
Lim Sang Min,
Gray Nathanael,
Westover Kenneth
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.650.2
Subject(s) - covalent bond , viability assay , chemistry , cell culture , biochemistry , cysteine , enzyme , biophysics , cancer research , cell , biology , genetics , organic chemistry
Many types of pancreatic, renal, and colon cancers are highly resistant to chemotherapy. A major contributor to this resistance is relatively high levels of TGF‐b‐activated kinase‐1 (TAK1) in the cancer cells, whose kinase activity leads to the suppression of pro‐apoptotic signaling pathways. Molecules which impede the binding of ATP to TAK1 have been developed as a strategy to overcome this resistance. They contain acrylamide groups that covalently attach to a cysteine in close proximity to the ATP‐binding site and irreversibly inhibit the activity of TAK1. Reversible analogs lacking the acrylamide group have been synthesized for comparison. We hypothesize that covalent inhibition of TAK1 will lead to loss of cell viability for selected cancer cell lines. The goal is to find cell lines where the covalent compound has significantly more activity than the non‐covalent counter‐part, suggesting that covalent TAK1 inhibition is responsible for the anti‐proliferative effects observed. We have examined the effect of three covalent‐ and non‐covalent‐binding pairs of inhibitors on the viability of six cell lines derived from these cancers. To test the viability we use the CellTiter‐Glow Assay, to determine the amount of ATP present in the cells. In many instances, the viability of these cell lines in culture was inhibited 50% – 100% compared to untreated controls following a 72‐hour exposure with 1 mM concentrations of the drugs. The covalent inhibitors were generally more effective than their non‐covalent analogs. One of the three pairs, Covalent SM1‐71, reduced viability of every cell line to a greater extent than the other two. The IC 50 values for this effect were determined by dose‐response analysis, and the most potent covalent inhibitor often produced values lower than 100 nM. Future experiments will examine whether the reduction in vitality is a direct result of inhibition of the TAK1 signaling axis. Ultimately, these compounds may have potential as clinical candidates.