Rabbit Anti-Human Wee1 (Phospho Ser123) Polyclonal antibody

Purpose Currently, the DNA damage response (DDR) pathway represents a key target for new cancer drug development. Advanced biliary tract cancer (BTC) has a poor prognosis because of the lack of efficacious treatment options. Although DNA repair pathway alterations have been reported in many patients with BTC, little is known regarding the effects of DDR-targeted agents against BTC. Materials and Methods In this study, nine BTC cell lines were exposed to the WEE1 inhibitor (AZD1775). In vitro, MTT assay, colony-forming assay, cell cycle analysis, phospho-histone H3 staining assay, Transwell migration assay, and western blot were performed. Then, to enhance the antitumor effect of AZD1775, the combination treatment of WEE1 inhibitor and ataxia telangiectasia mutated and Rad3 related (ATR) inhibitor (AZD6738) was conducted using MTT assay and comet assay. Finally, HuCCT-1 and SNU2670 xenograft models were established to confirm the anti-tumor effect of AZD1775 alone. Furthermore, the combination treatment was also evaluated in SNU2670 xenograft models. Results AZD1775 blocked the phosphorylation of CDC2 and CDC25C in all cell lines, but significantly increased apoptosis and S phase arrest in sensitive cells. However, increased p-ATR and phosphorylated ataxia telangiectasia mutated levels were observed in less sensitive cells. In addition, in vitro and in vivo data illustrated that AZD1775 combined with AZD6738 exerted more potent anti-tumor effects than either drug alone. Although WEE1 inhibition has promising anti-tumor effects in some BTC cells, the addition of ATR inhibitors could enhance its efficacy. Conclusion Taken together, this study supports further clinical development of DDR-targeted strategies as monotherapy or combination regimens for BTC.

Over the past decades, it is recognized that loss of DNA damage repair (DDR) pathways is an early and frequent event in tumorigenesis, occurring in 40-50% of many cancer types. The basis of synthetic lethality in cancer therapy is DDR deficient cancers dependent on backup DNA repair pathways. In cancer, the concept of synthetic lethality has been extended to pairs of genes, in which inactivation of one by deletion or mutation and pharmacological inhibition of the other leads to death of cancer cells whereas normal cells are spared the effect of the drug. The paradigm study is to induce cell death by inhibiting PARP in BRCA1/2 defective cells. Since the successful application of PARP inhibitor, a growing number of developed DDR inhibitors are ongoing in preclinical and clinical testing, including ATM, ATR, CHK1/2 and WEE1 inhibitors. Combination of PARP inhibitors and other DDR inhibitors, or combination of multiple components of the same pathway may have great potential synthetic lethality efficiency. As epigenetics joins Knudson's two hit theory, silencing of DDR genes by aberrant epigenetic changes provide new opportunities for synthetic lethal therapy in cancer. Understanding the causative epigenetic changes of loss-of-function has led to the development of novel therapeutic agents in cancer. DDR and related genes were found frequently methylated in human cancers, including BRCA1/2, MGMT, WRN, MLH1, CHFR, P16 and APC. Both genetic and epigenetic alterations may serve as synthetic lethal therapeutic markers.