Discovery of Rezatapopt (PC14586), a First-in-Class, Small-Molecule Reactivator of p53 Y220C Mutant in Development

BTB domain and CNC homolog 2: A master regulator that controls immune response and cancer progression

BTB domain and CNC homolog 2 (BACH2) is a transcription repressor from the basic region leucine zipper (bZIP) family. Although BACH2 is predominantly expressed in lymphoid cells, it plays pivotal roles throughout hematological development and differentiation, ranging from the regulation of hematopoietic stem and progenitor cell (HSPC) lineage commitment to the development of both innate and adaptive immune cells. Given its extensive regulation of immunity, it is not surprising that BACH2 has been implicated in cancer, particularly in hematological malignancies. While multiple findings indicate that BACH2 acts primarily as a tumor suppressor, other findings suggest that BACH2, whether within tumor cells or their surrounding microenvironment, may contribute to tumorigenesis and progression, highlighting the complexity of its roles and the diverse networks involved in different contexts. In this review, we provide a comprehensive overview of the evolving roles of BACH2 across various stages of hematopoiesis, with a particular focus on its associations with cancer and its therapeutic potential in a wide range of cancer types.

Deubiquitinase-Targeting Chimeras (DUBTACs) as a Potential Paradigm-Shifting Drug Discovery Approach

Developing proteolysis-targeting chimeras (PROTACs) is well recognized through target protein degradation (TPD) toward promising therapeutics. While a variety of diseases are driven by aberrant ubiquitination and degradation of critical proteins with protective functions, target protein stabilization (TPS) rather than TPD is emerging as a unique therapeutic modality. Deubiquitinase-targeting chimeras (DUBTACs), a class of heterobifunctional protein stabilizers consisting of deubiquitinase (DUB) and protein-of-interest (POI) targeting ligands conjugated with a linker, can rescue such proteins from aberrant elimination. DUBTACs stabilize the levels of POIs in a DUB-dependent manner, removing ubiquitin from polyubiquitylated and degraded proteins. DUBTACs can induce a new interaction between POI and DUB by forming a POI-DUBTAC-DUB ternary complex. Herein, therapeutic benefits of TPS approaches for human diseases are introduced, and recent advances in developing DUBTACs are summarized. Relevant challenges, opportunities, and future perspectives are also discussed.

Dehydrodiisoeugenol targets the PLK1-p53 axis to inhibit breast cancer cell cycle

Introduction

There are about 2,300,000 new cases of breast cancer worldwide each year. Breast cancer has become the first most common cancer in the world and the leading cause of death among women. At the same time, chemotherapy resistance in patients with advanced breast cancer is still a serious challenge. Alpinia Katsumadai Hayata (AKH), as a traditional Chinese herbal medicine, has a wide range of pharmacological activities. Related studies have found that many compounds in AKH have anti-breast cancer activity. However, it is still worth exploring which component is the main active component of AKH in inhibiting breast cancer and its mechanism of action.

Methods

In this study, dehydrodiisoeugenol (DHIE) was screened as the main active ingredient of AKH against breast cancer based on LC-MS combined with drug similarity and disease enrichment analysis. WGCNA, network pharmacology, molecular docking, transcriptome sequencing analysis, immune infiltration analysis and single-cell sequencing were used to explore the mechanism of DHIE on breast cancer. CCK-8, flow cytometry and Western blot were used to verify the results in vitro. The efficacy of the drugs was verified in vivo by constructing a subcutaneous tumor-bearing mouse model.

Results

Our research showed that DHIE and breast cancer enriched core gene targets mainly act on epithelial cells in breast cancer tissues and significantly inhibit the growth of breast cancer by affecting the PLK1-p53 signaling axis to arrest the breast cancer cell cycle at G0/G1 phase. Further analysis showed that although DHIE had opposite regulatory effects on different isoforms of p53 in different types of breast cancer cells, they eventually caused cell cycle arrest. In addition, in vivo studies showed that DHIE reduced tumor burden, significantly reduced the infiltration level of tumor proliferation-related marker Ki-67, and inhibited the expression of PLK1 in the mouse model, which was further enhanced when combined with DOX.

Discussion

Collectively, our study suggests that DHIE in AHK may eventually induce cell cycle arrest and inhibit breast cancer growth by regulating the PLK1-p53 signaling axis, which may provide a new therapeutic strategy for breast cancer. However, the specific mechanisms by which DHIE regulates p53 in different subtypes of breast cancer and the advantages of chemotherapeutic combinations compared with other drugs are still worth exploring.

Harnessing the TAF1 Acetyltransferase for Targeted Acetylation of the Tumor Suppressor p53

Pharmacological reactivation of the tumor suppressor p53 remains a key challenge for the treatment of cancer. Acetylation Targeting Chimera (AceTAC), a novel technology is previously reported that hijacks lysine acetyltransferases p300/CBP to acetylate the p53Y220C mutant. However, p300/CBP are the only acetyltransferases harnessed for AceTAC development to date. In this study, it is demonstrated for the first time that the TAF1 acetyltransferase can be recruited to acetylate p53Y220C. A novel TAF1-recruiting AceTAC, MS172 is discovered, which effectively acetylates p53Y220C lysine 382 in a concentration-, time- and TAF1-dependent manner via inducing the ternary complex formation between p53Y220C and TAF1. Notably, MS172 suppresses the proliferation in multiple p53Y220C-harboring cancer cell lines more potently than the previously reported p300/CBP-recruiting p53Y220C AceTAC MS78 with little toxicity in p53 WT and normal cells. Additionally, MS172 is bioavailable in mice and suitable for in vivo efficacy studies. Lastly, novel upregulation of metallothionine proteins by MS172-induced p53Y220C acetylation is discovered using RNA-seq and RT-qPCR studies. This work demonstrates that TAF1 can be harnessed for AceTAC development and expands the very limited repertoire of the acetyltransferases that can be leveraged for developing AceTACs, thus advancing the targeted protein acetylation field.