Approximately 40% of people will get
cancer in their lifetime in the US, and 20% are predicted to die from the condition when it is invasive and metastatic. Targeted screening for drugs that interact with
proteins that drive
cancer cell growth and migration can lead to new
therapies. We screened molecular libraries with the AtomNet® AI-based
drug design tool to identify compounds predicted to interact with the cytoplasmic domain of
protein tyrosine phosphatase mu.
Protein tyrosine phosphatase mu (
PTPmu) is proteolytically downregulated in
cancers such as
glioblastoma generating fragments that stimulate cell survival and migration. Aberrant nuclear localization of
PTPmu intracellular fragments drives
cancer progression, so we targeted a predicted
drug-binding site between the two cytoplasmic
phosphatase domains we termed a D2 binding pocket. The function of the D2 domain is controversial with various proposed regulatory functions, making the D2 domain an attractive target for the development of allosteric drugs. Seventy-five of the best-scoring and chemically diverse computational hits predicted to interact with the D2 binding pocket were screened for effects on tumour cell motility and growth in 3D culture as well as in a direct assay for
PTPmu-dependent adhesion. We identified two high-priority hits that inhibited the migration and
glioma cell sphere formation of multiple
glioma tumour cell lines as well as aggregation. We also identified one activator of
PTPmu-dependent aggregation, which was able to stimulate cell migration. We propose that the
PTPmu D2 binding pocket represents a novel regulatory site and that inhibitors targeting this region may have therapeutic potential for treating
cancer.