To comprehensively understand transcription factors (TFs), we created a barcoded library of all human TF splice isoforms and applied it to build a TF Atlas charting single-cell expression profiles of pluripotent stem cells overexpressing each TF. We validated TFs for generation of diverse cell types, spanning all three germ layers and trophoblasts. We further developed a strategy for predicting TF combinations that produce target cell types to accelerate cellular engineering.

We have developed synthetic cancer-targeting gene circuits that specifically target cancer cells. Once the circuits enter cells, they will sense the activity of several cancer-associated transcription factors and get activated in tumor cells to trigger tumor-localized combinatorial immunotherapy. Circuits mediate robust therapeutic efficacy in ovarian cancer mouse models. This platform can be adjusted to treat multiple cancer types and can potentially trigger genetically encodable immunomodulators as therapeutic outputs.

E1A binding protein (p300) and its paralog CREB binding protein (CBP or CREBBP) are key transcriptional co-activators that play a critical role in gene expression in both tumor and immune cells. Our efforts in understanding the distinct advantages of inhibition vs. degradation of CBP/p300 for use in cancer therapy resulting from a combination of synthetic lethality, inhibition of pro-tumorigenic signaling, and activation of anti-tumor immune response will be presented.

MYC proteins are highly validated but challenging targets for cancer therapy. In this talk, I will describe our efforts—in collaboration with Dr. Stephen Fesik—to target MYC via its chromatin cofactor WDR5. These efforts, now nearing completion, have generated highly potent, orally bioavailable, and safe drug-like WDR5 inhibitors that stymie the ability of MYC to promote protein synthesis and display anti-tumor activity in multiple MYC-driven cancer models.

TF-Scan is a live-cell assay that reports the proteome-wide changes in protein:DNA binding activity in response to small molecule perturbations. Using this technology, we discovered covalent compounds capable of binding and disrupting the activity of brachyury, a previously undruggable TF that drives sarcoma. Hit validation and medicinal chemistry led to a covalent chemical probe for brachyury, effective in chordoma cell line models with in vivo activity against patient-derived xenografts.

High-throughput CETSA (HT-CETSA) is a promising screening strategy for identifying target binders in the native cellular environment. We have performed HT-CETSA screening to enable chemical engagement of transcription factors. Here we will discuss key learnings from our HT-CETSA screening efforts.

I describe preclinical and clinical data for NX2127, a degrader of Bruton Tyrosine Kinase (BTK), a master regulator of B cells and implicated in cancer. We developed two unique and functionally distinct BTK degraders that harness cereblon (CRBN), an E3 ligase active in hematopoietic cells. I describe the BTK degrader that also has the ability to induce degradation of neosubstrates Ikaros (IKZF1) and Aiolos (IKZF3).

Transcription factors are known to bind to cereblon in the presence of molecular glues and some reports implicate interactions with multiple zinc fingers. We present biophysical and structural assessments of the minimal binding domains of IKZF2 and another transcription factor revealing that two zinc fingers interact with cereblon:glue complexes. In these examples, the binding modes are distinct and may have implications for the design of selective degraders.

IKZF2 (Helios) plays an important role in maintaining stability and function of regulatory T cells (Tregs). Proteovant applied a structure-guided drug discovery approach to identify an IKZF2 selective molecular glue degrader, PVTX-405. PVTX-405 shows selective degradation of IKZF2 in vitro and in vivo. PVTX-405 treatment reduces suppressive activity of human Treg cells ex vivo and delays growth of MC38 tumors in immune competent mice in vivo.

The Jian Jin Laboratory at Mount Sinai is a leader in discovering novel degraders targeting oncogenic proteins and developing new technologies for advancing the targeted protein degradation field. Our lab’s recent progress advancing the targeted protein degradation, including TF-PROTAC, Bridged PROTAC, Folate-caged PROTAC, opto-PROTAC, and KEAP1-recruiting PROTAC technologies will be presented.

STAT (signal transducer and activator of transcription) proteins are a family of transcription factors that mediate signal transduction downstream of cytokine and growth factor receptors. Hyperactivation of STAT3 and STAT5 has been linked to cancer cell proliferation, survival, stemness, and immune evasion, making them attractive targets for cancer therapy. STATs have been difficult to target by traditional small-molecule inhibitors. Employing the PROTAC technology, we have developed highly selective and potent STAT3 or STAT5 degraders with strong anti-tumor activities in hematologic cancer models.