Notch2 Gene Editing    

Notch constitutes an evolutionarily conserved intercellular signalling pathway that determines cell fate in different organs. This pathway is activated by interaction between Notch receptors and ligands between adjacent cells. Upon activation, Notch receptors are cleaved by γ-secretase and the intracellular domains translocate into the nucleus, where the transcription of target genes starts. There are four receptors (Notch1, Notch2, Notch3 and Notch4) and five ligands (Jagged1, Jagged2, DLL (Delta-like ligand)-1, DLL-3 and DLL-4) in mammalian organs. Notch pathways have critical roles in each stage during development. Notch-ligand interactions lead to a series of proteolytic cleavages causing the release of the NICD, which translocates to the nucleus and interacts with C promoter binding factor 1, suppressor of hairless or Lag-1 (CSL), also known as Rbpjk, and with mastermind like (MAML) proteins to regulate transcription. This is considered the Notch canonical signaling pathway, and it is known to induce the transcription of hairy and enhancer of split (Hes) 1, 5, and 7 and Hes related with YRPW-motif (Hey) 1, 2, and L. In the canonical pathway, the formation of the Notch transcriptional complex, consisting of NICD, CSL, or Rbpjk and MAML leads to the displacement of transcriptional repressors and the induction of Notch target gene transcription.

Notch2 and Cancer

Notch1 is suspected to have growth-promoting functions in non-small cell lung cancer (NSCLC), and functions as a tumor suppressor in small cell lung carcinoma (SCLC). Notch3 behaved as a tumor-promoting pathway in NSCLC, and Notch1 as a tumor suppressing pathway in SCLC, but some functional differences were observed between Notch1 and Notch3. On the contrary, Notch2 has not been well investigated in the biological significance of neuroendocrine proliferation, differentiation, metastasis, and drug resistance of lung cancers. A structural study of NOTCH2 has shown that NOTCH1, NOTCH2, and NOTCH3 were similar to each other, but that sequence differences among them suggested subtle, but potentially important differences. In addition, the length and composition of the linker connecting the epidermal growth factor-like repeats to the extracellular negative regulatory region is very different among Notch receptors. The pathobiological significance of Notch2 has been studied in various cancers. In breast cancer, Notch2 is reported to be involved in radiation-induced epithelial to mesenchymal transition (EMT), tumor differentiation, induced malignant tumor growth, and chemo-resistance. In pancreatic cancer, Notch2 positive cells have properties of cancer stem cells, which are positively correlated with the differentiation grade of pancreatic ductal adenocarcinoma (ADC), and contribute to the regulation of EMT of gemcitabine-resistant pancreatic cancer cells. Among malignant lymphoma, Notch2 is implicated in the pathogenesis of B-cell lymphoma, and Notch2 mutations play a role in the pathogenesis and progression of splenic marginal zone lymphoma.

Notch2 as A Potential Therapeutic Target

Sustained Notch2 signaling facilitates the stem-like ability of tumor cells to avoid apoptotic cell death while undergoing self-renewal and promoting the EMT, and increased Notch2 expression is associated with poor clinical prognosis in patients. Notch2 further increases the chemo- and radio-resistance of tumor cells, thereby reducing these cancers less sensitive to therapeutic treatment. At the post-transcriptional level, interfering with the cleavage-mediated maturation of Notch2 represents one potential therapeutic strategy. The S1 and S2 cleavage steps of hNotch2 are different from those of Notch1 and from those of murine Notch2, although the specifics of these differences are incompletely characterized. Therefore, further efforts are needed to fully understand whether these two cleavage steps represent viable targets for pharmacological inhibition. The γ-secretase inhibitor DAPT is able to block S3 cleavage, but it indiscriminately interferes with the cleavage of all Notch subtypes, and Notch2 can in some cases exhibit DAPT resistance. Thus, tankyrase 1 represents a potentially superior target for disrupting Notch2 S3 cleavage and for promoting its proteasomal degradation. Like Notch receptors, Delta-like and Jagged ligands also undergo ADAM10/17 and γ-secretase-mediated proteolysis following receptor interactions after binding to receptors. Using an antibody to block Jagg-ed1 has been found to reduce Jag1-IC activation, thereby reducing cell viability.

Figure 1. Oncogenic Notch2 signaling and potential therapeutic targets. (Xiu M X, Liu Y M., 2019)

NOTCH2 Gene Editing Services

CRISPR/Cas9 Platform^CB at Creative Biogene is dedicated to offering comprehensive CRISPR/Cas9 gene editing services and products for academic research, biotech research and pharmaceutical drug discovery. With deep gene editing knowledge and extensive experience in experimental operation and data processing, we help you effectively control NOTCH2 genes knockout/knockin/point mutation in cells or animals via CRISPR/Cas9 technology.

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