Panoply™ Human TTK Over-expressing Stable Cell Line

Multiple myeloma (MM) is a malignant proliferative disease of plasma cells that remains incurable. Threonine and tyrosine kinase (TTK) is a dual-specificity protein kinase that phosphorylates serine/threonine and tyrosine residues. Its elevated expression is associated with poor prognosis in various cancers. Here, researchers found that TTK is significantly overexpressed in multiple myeloma patients and cell lines. TTK knockdown promoted MM cell apoptosis and G0/G1 phase arrest while inhibiting cell proliferation; conversely, TTK overexpression reduced MM cell apoptosis and G0/G1 phase arrest, and enhanced cell proliferation. Next, proteomic analysis identified regucalcin (RGN) as a downstream target of TTK. Cell function experiments showed that RGN knockdown significantly promoted MM cell proliferation, inhibited apoptosis, and reduced cell cycle arrest, and reversed the increased apoptosis, decreased proliferation, and enhanced cell cycle arrest caused by TTK knockdown. Finally, a xenograft mouse model showed that TTK significantly promoted the development and progression of MM. In summary, these results indicate that the TTK-RGN axis regulates apoptosis, G0/G1 phase arrest, and proliferation of MM cells, suggesting that TTK is a potential therapeutic target for multiple myeloma.

To better understand the regulatory role of TTK in the behavior of multiple myeloma (MM) cells, researchers constructed AMO-1 cells that stably overexpressed TTK (Figure 1A, B). CCK-8 assay was used to assess cell proliferation, and the results showed that the proliferative capacity of TTK-overexpressing AMO-1 cells was significantly increased (Figure 1C). The researchers also evaluated the effect of TTK overexpression on the cell cycle. Flow cytometry results showed that TTK overexpression effectively inhibited apoptosis in MM cells (Figure 1D). Western blotting results showed that the expression levels of apoptosis-related proteins Bax, Cleaved-PARP1, and Cleaved-caspase were decreased in TTK-overexpressing AMO-1 cells, while the level of Bcl-2 was increased (Figure 1E). Furthermore, flow cytometry results showed that TTK overexpression reduced the proportion of AMO-1 cells in the G0/G1 phase, while increasing the proportion in the S and G2/M phases (Figure 1F). The expression levels of CCNE1, CDK2, CDK4, and CCND1 proteins were increased in TTK-overexpressing cells (Figure 1G). Therefore, TTK overexpression can promote the proliferation of MM cells, reduce apoptosis, and regulate the cell cycle, preventing it from being arrested in the G0/G1 phase.

Figure 1. Overexpression of TTK could inhibit apoptosis, promote proliferation, and modulate the cell cycle of MM cells. (Zhu X F, et al., 2024)