Unraveling the Potential of EphA4: A Breakthrough Target and Beacon of Hope for Neurological Diseases

Back-Pocket Optimization of 2-Aminopyrimidine-Based Macrocycles Leads to Potent EPHA2/GAK Kinase Inhibitors

“…Introduction of polar groups such as the carboxymethyl (41) or methoxy (44) did not improve potency. Having a fluorine (23,48,49,51,53), chlorine (42,54), or bromine (55) substituent at the 4′-position correlated with high ΔT m values, as long as the substituent in position 3 was not too bulky. For example, introduction of isopropoxy (43), trifluoromethyl (47), or carboxymethyl (50) at the 3-position resulted in almost complete loss of binding, highlighting the spatial limitations of the back pocket.…”

“…Macrocycles 75 and 79 exhibited only micromolar EC 50 values for EPHA2 in the NanoBRET assay but displayed significantly improved potency against EPHA4, whereas their potency against GAK remained unchanged. This observation could serve as a promising starting point for future inhibitor development, especially as EPHA4 represents an intriguing target not only in different types of cancers but also in neurological pathologies such as amyotrophic lateral sclerosis or Alzheimer’s disease. − …”

Back-pocket optimization of 2-aminopyrimidine-based macrocycles leads to potent dual EPHA2/GAK kinase inhibitors with antiviral activity

“…This observation could serve as a promising starting point for future inhibitor development, especially as EPHA4 represents an intriguing target not only in different types of cancers but also in neurological pathologies such as amyotrophic lateral sclerosis or Alzheimer's disease. [44][45][46][47][48] Notably, the in cellulo GAKselective compounds 75 and 79 showed no antiviral activity against DENV infection, which was unexpected, given that GAK is a known antiviral target. 27 To the best of our knowledge, inhibition of EPHA2 has not been reported as a strategy to combat DENV infection so far.…”

“…Having a fluorine(23,48,49,51,53), chlorine(42,54), or bromine(55) substituent at the 4'-position correlated with high Tm values, as long as the substituent in position 3 was not too bulky. For example, introduction of isopropoxy(43), trifluoromethyl(47), or carboxymethyl(50) at the 3position resulted in almost complete loss of binding, highlighting the spatial limitations of the back pocket. The highest Tm values for EPHA2 were observed for 23, 48, and 52, which had all Tm values >8 K. For GAK, compounds 42, 52, 53, and 55 showed Tm values of more than 7 K. Compounds 45, 46, 48, and 49 showed the highest Tm stabilization for the off-targets FGFR1/2 and FLT1.…”