Carbonic
anhydrase IX (CAIX) is a membrane-bound enzyme associated
with tumor hypoxia and found to be over expressed in various tumor
conditions. Targeting CAIX catalytic activity is proven to be efficient
modality in modulating pH homeostasis in cancer cells. Proteoglycan-like
(PG) region is unique to CAIX and is proposed to serve as an antenna
enhancing the export of protons in conjunction with facilitated efflux
of lactate ions via monocarboxylate transporters. Moreover, the PG
region is also reported to contribute to the assembly and maturation
of focal adhesion links during cellular attachment and dispersion
on solid supports. Thus, drug targeting of this region shall efficiently
modulate pH homeostasis and cell adhesion in cancer cells. As the
PG region is intrinsically disordered, the complete crystal structure
is not elucidated. Hence, in this study, we intend to sample the conformational
landscape of the PG region at microsecond scale simulation in order
to sample the most probable conformations that shall be utilized for
structure-based drug design. In addition, the sampled conformations
were subjected to high-throughput virtual screening against NCI and
Maybridge datasets to identify potential hits based on consensus scoring
and validation by molecular dynamics simulation. Further, the identified
hits were experimentally validated for efficacy by in vitro and direct
enzymatic assays. The results reveal 5-(2-aminoethyl)-1,2,3-benzenetriol
to be the most promising hit as it showed significant CAIX inhibition
at all levels of in silico and experimental validation.