FIGURE 6 from Inhibition of NEK2 Promotes Chemosensitivity and Reduces KSHV-positive Primary Effusion Lymphoma Burden

figure

posted on 2024-04-09, 15:20 authored by Maria C. White, Jason P. Wong, Blossom Damania

NEK2 inhibition decreases tumor burden and prolongs survival in PEL xenograft mice. A, Weights of PEL-bearing mice over time treated with vehicle control (DMSO, black line) or 15 mg/kg JH295 (gray line). Data represent mean ± SD. B, Survival curves of PEL-bearing mice treated with DMSO (black line) or 15 mg/kg JH295 (gray line). Data were analyzed using log-rank (Mantel–Cox) test. ****P < 0.0001. C, Quantification of PEL burden (as measured by luminescence) in mice treated with DMSO or 15 mg/kg JH295. Data were analyzed using multiple unpaired t tests. ns, not significant, ****, P < 0.0001. D, Representative IVIS imaging of PEL burden in mice treated with vehicle (DMSO) or 15 mg/kg JH295 at 21 days posttreatment. E, Quantification of total effusion volume isolated from the peritoneal cavity of PEL-bearing mice at endpoint treated with either DMSO or 15 mg/kg JH295. Data were analyzed using unpaired two-tailed t test. **, P = 0.0066. All data (unless otherwise stated) are pooled from three independent biological replicates. F, Quantification of PEL burden (as measured by luminescence) in mice treated with DMSO or 15 mg/kg JH295. Data were analyzed using paired two-tailed t test. ns, not significant; **, P = 0.0025. G, IVIS imaging of PEL burden in mice treated with vehicle (DMSO) or 15 mg/kg JH295 at 22 days posttreatment. Red circles indicate the region of interest, and tumor burden (as measured by luminescence) is indicated above each mouse (same data in F). H, Weight of solid tumors isolated from PEL-bearing mice treated with either DMSO or 15 mg/kg JH295 at 23 days posttreatment. Data were analyzed using unpaired two-tailed t-test. ***P = 0.0002. I, Quantification of total effusion volume isolated from the peritoneal cavity of PEL-bearing mice at 23 days posttreatment. Data were analyzed using unpaired two-tailed t test. **, P = 0.001. J and K, Total number of cells (J) and % dead cells (K) isolated 23 days posttreatment from the peritoneal cavities of PEL-bearing mice treated with either DMSO or 15 mg/kg JH295. For 4/5 JH295-treated mice, no effusion was present, so cells were collected via peritoneal lavage using 1 mL PBS. Two samples in the JH295 treatment group were contaminated with red blood cells and therefore omitted. Data were analyzed using unpaired two-tailed t test. **, P < 0.0025. L, Quantification of ALT present in the sera of PEL-bearing mice at 23 days posttreatment. Data were analyzed using unpaired two-tailed t test. ns, not significant.

Funding

HHS | National Institutes of Health (NIH)

American Cancer Society (ACS)

History

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.