Important Compound Classes
Title
Degraders of WEE1 Kinase.
Patent Publication Number
WO 2020/069105 A1
Publication Date
April 02, 2020
Priority Application
US 62/737,523
Priority Date
September 27, 2018
Inventors
Gray, N. S.; Scott, D.; Li, Z.; Pinch, B. J.; Olson, C.; Fischer, E. S.; Nowak, R. P.; Donovan, K. A.
Assignee Company
Dana-Farber Cancer Institute, Inc., 450 Brookline Avenue, Boston, Massachusetts 02215 USA.
Disease Area
Cancer
Biological Target
WEE1 Tyrosine Kinase.
Summary
The cell cycle is a highly regulated process, and several mechanisms exist by which the cells modulate the progression, including factors that affect DNA replication or DNA damage. The cell-cycle checkpoints enable the cells to repair damaged DNA prior to transmission into mitosis, and the cyclin-dependent kinases (CDK) coordinate the progression through the cell cycle. For instance, the progression from G2 into mitosis is controlled by the CDC2/cyclin B complex (CDK1/cyclin B). The blockade at the G2 checkpoint is especially important for p53 mutant cells, which have the opportunity to arrest the cell cycle at the G1 checkpoint such that defective P53 pathway relies mainly on DNA repair at the G2 checkpoint. In normal cells, the G2 checkpoint is not burdened with halting the cell cycle prior to DNA damage repair. In cancer cells, however, there is a deficient G1 checkpoint that impairs the ability of the cell to halt the cell cycle in order to repair DNA damage prior to replication, which accumulates mutations and propagates irregularities that are favorable to cancer formation. WEE1 is a protein kinase involved in many cellular processes, one of which is its role as a regulator of the S-phase and G2-M cell-cycle checkpoint, which respond to DNA damage or replication stress. The majority of human cancer cells have a deficient G1-S checkpoint, often via mutation of p53, and are particularly reliant on a functional G2-M checkpoint to avoid mitotic catastrophe and apoptosis. WEE1 phosphorylates CDK and restrains their activity and prevents premature entry into mitosis until DNA is repaired. Thus, WEEl is essential to the DNA repair process and is viewed as a mitotic gatekeeper, whose activity is reduced after the damaged DNA is repaired and the cells transition into cell division (mitosis). The overexpression of WEE1 has been reported in several cancer types, including breast, gastric, ovarian, colorectal, sarcoma, and malignant melanoma.
Many anticancer treatments such as ionizing radiation, alkylating agents, antimetabolites, platinum compounds, and DNA topoisomerase inhibitors exert their activity by DNA damage in tumor cells, which also initiate activation of cell cycle checkpoints, including WEEl and CDK1 and 2. This gives the tumor cell time to repair the damaged DNA before it begins mitosis. Consequently, tumor cells can exploit the DNA repair process and render them refractory or even immune to the anticancer therapy. Therefore, the abrogation of the G2-M checkpoint by the inhibition of WEEl sensitizes tumors to the effects of DNA-damaging therapies mentioned above.
AZD1775 is an adenosine triphosphate (ATP)-competitive WEEl small molecule inhibitor that inhibits downstream phosphorylation of CDK1 on Tyr15, which has been shown to induce premature mitotic entry, sensitize p53 mutant tumor cells to DNA-damaging agents, and cause tumor regression in preclinical cancer models, and it enabled numerous clinical trials in combination with a variety of DNA-damaging agents in advanced leukemia and solid tumors. There are over 20 completed or actively recruiting AZD1775 clinical trials (https://clinicaltrials.gov/ct2/results?cond=AZD1775&term=&type=&rslt=&recrs=a&recrs=e&age_v=&gndr=&intr=&titles=&outc=&spons=&lead=&id=&cntry=&state=&city=&dist=&locn=&rsub=&strd_s=&strd_e=&prcd_s=&prcd_e=&sfpd_s=&sfpd_e=&rfpd_s=&rfpd_e=&lupd_s=&lupd_e=&sort=, accessed 2020-06-09). However, AZD1775 promising efficacy in the clinic has been associated with a number of dose-limiting toxicities, including anemia, nausea, neutropenia, thrombocytopenia, and off-target activity against other kinases such as equipotent activity against recombinant WEEl and the Ser/Thr kinase, PLK1.
Bifunctional compounds may be used in the treatment of cancer as a monotherapy or by way of combination therapy. The combination treatment regimens include radiation therapy, chemotherapeutics such as mitotic inhibitors, alkylating agents, HDAC inhibitors, angiogenesis inhibitors, antihormones, autophagy Inhibitors etc., immunomodulators, therapeutic antibodies, CHK1 inhibitors, and CAR-T therapy.
This Patent Highlight shows bifunctional compounds (degraders) of targeted WEEl kinase for degradation. The linker provides a covalent attachment to the targeting ligand and the degron. The PROTAC compounds tag WEE1 for ubiquitination and degradation via the cullin 4A/B-DDB1–cereblon E3–ubiquitin ligase complex. For the catalytic activity, after destruction of a WEE1 bound complex, the degrader is released and continues to be active, which may represent a potential improvement over traditional small molecule inhibitors of aberrant proteins in the treatment of cancers.
Key Structures
Biological Assay
Immunoassay was visualized using the ODYSSEY Infrared Imaging System (LICOR). Cell viability assays were assessed by using the CellTiter-Glo Luminescent Cell Viability Assay. In vitro Wee1 kinase dose–response was done using LanthaScreen assays. Compound 13 induced potent degradation of WEE1 in a CRBN- and proteasome-dependent manner with maximal degradation at 100 nM.
Biological Data
The table below
shows the extent to
which representative compounds induced degradation of WEE1 at 1 μM,
via the immunoblots in MOLT4 cells after a 6 h treatment.
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The author declares no competing financial interest.