Project Summary
The past two decades of cancer research have identified one or more drivers for most human
malignancies. In addition, multiple cell death genes and pathways have been identified that
normally protect the organism against developmental mutations or defects in genomic
maintenance. These observations suggest that one might be able to rewire the transcriptional
circuitry to cause the cancer cell to kill itself with its own driver. We have invented a new class
of molecules that use Chemically Induced Proximity (CIP) to rewire the cancer cell such that the
cancer driver activates proapoptotic pathways. We call these molecules Transcriptional
Chemical Inducers of Proximity or TCIPs because they induce proximity or recruit a cancer
driver to the promoters of proapopotic genes. For development of these two-sided, “bifunctional”
molecules, we will focus on Diffuse Large Cell B Cell Lymphoma (DLBCL), using the master
inhibitor of cell death, BCL6, as an anchoring transcription factor on the promoters of
proapoptotic genes. For an activator we use any of several aberrantly-expressed transcription
or epigenetic activators, to simultaneously derepress and activate proapoptotic genes. We have
synthesized bifunctional small molecules that recruit transcriptional activators over-expressed in
DLBCL to the promoters of proapoptotic genes normally bound and repressed by BCL6. In our
preliminary studies, these molecules lead to rapid and robust killing of DLBCL that is superior to
the best-in-class inhibitors and also specific for cells that over-express the targets of the
bifunctional molecule. Using a strategy similar to genetic dominant gain-of-function mutations,
TCIP can engage cancers with multiple drivers, thereby going beyond conventional inhibitors
and degraders. Because bifunctional molecules rely on two separately overexpressed proteins,
TCIP takes advantage of the natural, fundamental basis of transcriptional specificity to provide
precise, predictable and selective killing of cancer cells. To further develop this approach, we
will first optimize these molecules for stability, solubility and specificity of killing of DLBCL.
Secondly, we will define the mechanism by which they produce robust and rapid killing. Finally,
we will test them in established PDX models. Our studies will involve a multidisciplinary
approach drawing on expertise in chemistry, clinical lymphoma treatment, cancer biology and
genomic biology. If successful, we will lay the foundation for a new concept in the treatment of
lymphoma, and more broadly, cancer chemotherapy, that is more specific than many existing
approaches. The use of a novel dominant gain-of-function strategy by TCIPs addresses the
issue of treatment of cancers, such as DLBCL, that have multiple, concurrent drivers.