Panoply™ Human PRAME Knockdown Stable Cell Line

Multiple myeloma (MM) is a disease characterized by dysfunction of the ubiquitin-proteasome system (UPS). Previous studies have shown that elevated PRAME transcript levels are associated with unfavorable progression-free survival (PFS) in patients not treated with bortezomib, whereas bortezomib-containing regimens significantly improve PFS in patients with elevated PRAME transcript levels, suggesting that PRAME expression is a prognostic marker for MM and is associated with proteasome inhibitor therapy. Here, researchers established MM cell models with both PRAME knockdown and overexpression and found that PRAME plays a proliferative role in MM cells. Overexpression of PRAME was found to activate P-Akt signaling. As the substrate recognition subunit (SRS) of an E3 ubiquitin ligase, PRAME targets substrate proteins and mediates their degradation. CTMP and p21 were identified as novel targets of PRAME in this Cul2-dependent substrate recognition process. PRAME interacts with CTMP and p21 and mediates their ubiquitination and degradation, leading to the accumulation of p-Akt and CCND3 proteins, thereby promoting cell proliferation and increasing the sensitivity of MM cells to bortezomib.

Flow cytometry analysis showed that PRAME knockdown in RPMI8226 and LP-1 cells increased the proportion of cells in the G0/G1 phase and decreased the proportion of cells in the S phase (Figures 1A-D). Overexpression of PRAME in LP-1 cells reversed the observed pattern (Figures 1E and F), suggesting that PRAME promotes the transition from the G0/G1 phase to the S phase of the cell cycle. Furthermore, IHC revealed lower Ki67 expression in tumors from the PRAME knockdown group compared to the control group (Figures 1G and H). Furthermore, the migration and invasion abilities of PRAME knockdown cells were significantly reduced. Overexpression of PRAME produced the opposite effect.

Figure 1. PRAME promotes cell cycle progression in MM cells. (Sun K, et al., 2024)