Panoply™ Human DLL3 Over-expressing Stable Cell Line

The notch signal pathway is important in the development of both tumor-associated macrophages (TAMs) and stomach cancer, but how Notch signaling affects TAMs in gastric cancer remains unclear. Here, researchers demonstrate that co-culture of macrophages with gastric cancer cells MKN45 and BGC823 promotes cell proliferation, concurrently activating Notch1/Notch2 signaling and upregulating DLL3. This process can be blocked by Notch signaling γ-secretase inhibitor (DAPT). Overexpression of DLL3 in gastric cancer cells promotes cancer cell proliferation, enhances Notch1/Notch2 signaling, induces IL-33 expression, leads to degradation of galectin 3-binding protein (LG3BP) and heat shock cognate 71 kDa protein (HSPA8), and increases macrophage secretion of IL-1β, IL-12, and IL-10. This demonstrates that DLL3 regulates macrophages in gastric cancer and suggests that DLL3 may be a novel potential target for stomach-cancer therapy.

In DLL3-overexpressing MKN45 (DLL3-MKN45) and BGC823 (DLL3-BGC823) cells, N1ICD and N2ICD protein expression levels were upregulated (Figure 1A). Conversely, those were downregulated in siRNA-mediated DLL3-inhibited MKN45 (siRNA-DLL3-MKN45) and BGC823 (siRNA-DLL3-BGC823) cells (Figure 1B). On days 3 and 6, DLL3-overexpressing MKN45 and BGC823 cells proliferated faster than corresponding control cells (Figure 1C). Conversely, cells with DLL3 knockdown exhibited a slower proliferation rate compared to control cells (Figure 1D). Furthermore, migration was enhanced in DLL3-overexpressing MKN45 and BGC823 cells. Regarding the cell cycle, DLL3 overexpressing stable Cells were first analyzed by flow cytometry, and Annexin V fluorescein isothiocyanate/propidium iodide (Annexin V FITC/PI) staining was used to distinguish the apoptotic state of the cells. The results showed no significant differences between the treated cells and the control group, suggesting that DLL3 may not act through apoptotic signaling. In MKN45 and BGC823 cells, DLL3 knockdown increased the proportion of cells in the G0/G1 phase, while decreasing the proportion of cells in the S phase, indicating that DLL3 knockdown reduces the G1/S transition in gastric cancer cells. Taken together, these data indicate that DLL3 promotes the proliferation and migration of gastric cancer cells.

Figure 1. The changes in Notch signal proteins in stomach-cancer cells and cell proliferation after the overexpression and downregulation of DLL3. (Ye J B, et al., 2022)