Signal transducer and activator of
transcription 3 (STAT3) is a
transcription factor that regulates various biological processes,
including proliferation, metastasis, angiogenesis, immune response,
and chemoresistance. In normal cells, STAT3 is tightly regulated to
maintain a transiently active state, while persistent STAT3 activation
occurs frequently in cancers, associating with a poor prognosis and
tumor progression. Targeting the STAT3 protein is a potentially promising
therapeutic strategy for tumors. Although none of the STAT3 inhibitors
has been marketed yet, a few of them have succeeded in entering clinical
trials. This Review aims to systematically summarize the progress
of the last 5 years in the discovery of directive STAT3 small-molecule
inhibitors and degraders, focusing primarily on their structural features,
design strategies, and bioactivities. We hope this Review will shed
light on future drug design and inhibitor optimization to accelerate
the discovery process of STAT3 inhibitors or degraders.