Panoply™ Human ENPP2 Over-expressing Stable Cell Line

Ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) has been found to be associated with tumorigenesis and development. Here, researchers show that ENPP2 expression levels are higher in CD138+ cells isolated from multiple myeloma (MM) patients than in CD138- cells. IL-6 treatment of MM cells upregulates ENPP2 expression. ENPP2 overexpression promotes MM cell proliferation, inhibits apoptosis, increases lysophosphatidic acid (LPA) production, and upregulates the expression of osteoclastogenesis-related factors. Conversely, ENPP2 inhibition induces apoptosis, suppresses cell proliferation and survival, reduces LPA production, and downregulates the expression of osteoclastogenesis-related factors. In a mouse model of MM xenograft, ENPP2 knockdown significantly reduced MM tumor burden by inhibiting cell proliferation and inducing apoptosis. Furthermore, ENPP2 knockdown reduced the levels of LPA and osteoclastogenesis mediators in the serum of MM mice. These results reveal the pro-tumorigenic role of ENPP2 in MM, providing new molecular evidence for targeting the ENPP2-LPA axis for MM treatment.

To investigate the effects of ENPP2 overexpression on metastatic muscular dystrophy (MM) cells, researchers constructed ENPP2-overexpressing U266B1 cells (Figure 1A, B). Proliferation and apoptosis experiments showed that apoptosis was inhibited in ENPP2-overexpressing cells (Figure 1C), while the proliferation of U266B1 cells was enhanced (Figure 1D). ENPP2 is an enzyme capable of generating the bioactive lipid mediator LPA. Therefore, researchers analyzed the levels of LPA and its receptors in the supernatant of MM cells. RT-qPCR results showed that U266B1 cells expressed mRNA of six LPA receptor subtypes (LPAR1, LPAR3, LPAR4, LPAR5, and LPAR6) (Figure 1E). ELISA was used to detect LPA levels in the supernatant of ENPP2-overexpressing cells or control MM cells. The results showed that compared with the control cell supernatant, the LPA level in the supernatant of ENPP2-overexpressing MM cells was significantly increased (Figure 1F). Osteolytic lesions are a hallmark of MM, leading to bone pain and fractures in MM patients. Therefore, researchers investigated the expression of osteoclast activating factor (ENPP2) in MM cells. ENPP2 overexpression led to upregulation of both RANKL and MIP-1α mRNA and protein levels (Figure 1G,H). These results indicate that ENPP2 overexpression promotes MM cell proliferation, inhibits apoptosis, increases LPA production, and upregulates ENPP2 expression.

Figure 1. ENPP2 overexpression promotes proliferation, inhibits apoptosis, increases LPA generation, and upregulates osteoclast activation factors in MM cells. (Li Y, et al., 2022)