Figure S4. NEK2 inhibition in PEL results in decreased expression of the transcription factor, beta-catenin, and the pro-survival protein, Bcl-xL. (A) Western blot for total beta-catenin, phosphorylated beta-catenin (Ser33/Ser37/Thr41, ~92 kDa band), and Bcl-xL in PEL cells treated with or without JH295 for 48h. GAPDH was used as the loading control. Data are representative of three independent biological replicates. (B) Western blot for phosphorylated beta-catenin (Ser33/Ser37/Thr41) and Bcl-xL in PEL cells with intact NEK2 expression (NTC) or depleted NEK2 expression (shRNA). GAPDH was used as the loading control. Data are representative of two-three independent biological replicates. (C) Viability of PEL cells treated with vehicle control (DMSO) or the Bcl-xL inhibitor, A-1155463, for 48h. Data are plotted as individual values from three-four independent biological replicates and normalized to the DMSO control values for each treatment. Data represent mean ± SD and were analyzed using two-way ANOVA with Dunnett’s multiple comparisons. ****p < 0.0001.
ARTICLE ABSTRACT
Non–Hodgkin lymphoma (NHL) is a common cancer in both men and women and represents a significant cancer burden worldwide. Primary effusion lymphoma (PEL) is a subtype of NHL infected with Kaposi sarcoma–associated herpesvirus (KSHV). PEL is an aggressive and lethal cancer with no current standard of care, owing largely to its propensity to develop resistance to current chemotherapeutic regimens. Here, we report a reliance of KSHV-positive PEL on the mitotic kinase, NEK2, for survival. Inhibition of NEK2 with the inhibitor, JH295, resulted in caspase 3–mediated apoptotic cell death of PEL. Furthermore, NEK2 inhibition significantly prolonged survival and reduced tumor burden in a PEL mouse model. We also demonstrate that the ABC transporter proteins, MDR1 and MRP, are most active in PEL and that inhibition of NEK2 in PEL reduced the expression and activity of these ABC transporter proteins, which are known to mediate drug resistance in cancer. Finally, we report that JH295 treatment sensitized lymphomas to other chemotherapeutic agents such as rapamycin, resulting in enhanced cancer cell death. Overall, these data offer important insight into the mechanisms underlying PEL survival and drug resistance, and suggest that NEK2 is a viable therapeutic target for PEL.
The mitotic kinase, NEK2, is important for the survival of KSHV-positive PEL. NEK2 inhibition resulted in PEL apoptosis and reduced tumor burden in a mouse model. NEK2 inhibition also reduced drug resistance.
