E7046

Cell experiment:

Bone marrow (BM) cells are flushed from femurs of BALB/c mice using sterile CM. Freshly harvested (BM) cells (0.5×106) are differentiated in the presence of 20 ng/mL recombinant mouse GM-CSF, ±PGE2 (10 nM), at 37°C, for 8 d. CM C fresh GM-CSF ± PGE2 is changed on days 3 and 6. After in vitro differentiation, cells are analyzed by flow cytometry. For certain experiments, CT26, 4T1 cell supernatants, and/or EP1 (SC-57089), EP2 (ER-880696), EP3 (L-798106), or EP4 (E7046) antagonists at 1 mM, are added to the BM cells. To assess the effect of differentiated BM cells on T cell proliferation, mouse BM cells differentiated are co-cultured for 72 hours with anti-CD3/CD28 Dynabeadsstimulated and CFSE (1 mM)-stained T cells. T cell proliferation is assessed by CFSE dilution using flow cytometry.

Animal experiment:

For the tumor isograft efficacy studies, 6-week old female BALB/c mice are implanted with cancer cells: 1×105 CT26 or 4T1 cells or 8×105 H22 cells per mouse s.c., or 1×105 EMT6 cells in the mammary fat pad. C57BL/6 mice are implanted s.c. with 1×106 Pan02 cells per mouse, and A/J mice are implanted s.c. with 2-3 mm3 SAI/N tumor fragments. To investigate the role of T cells in the anti-tumor response, 6 week old female nude mice (which lack T cells) are injected s.c. with 1×105 CT26 cells. When tumors reach approximately 50-100 mm3, tumor-bearing mice are randomly assigned to vehicle or treatment groups, and treatment regimens begin. E7046 is administered per oral (p.o.) as a 100 or 150 mg/kg suspension in 0.5% MC, daily for 21 d (QDx21). For the combination studies, E7777 is administered intravenously (i.v.) at 2.5 mg/mouse in saline, as 2 to 3 doses injected one week apart (Q7Dx2-3). Tumor volumes and body weights are recorded 2-3 times a week. For comparison with current immunotherapies, in addition to vehicle control and E7046 C E7777 groups, mice are assigned to anti-PD1 antibodies or anti-mouse PD-1 C antimouse CTLA4 antibodies treatment groups. Anti-PD-1 and anti-CTLA-4 antibodies (1 mg/mL), are administered i.p. in 100 mL, 3 times 4 d apart (Q4Dx3) for a total of 300 mg each. Isotype controls are administered i.p. at 1 mg/mL to the control group. For the CD4CT and CD8CT lymphocyte depletion, antimouse CD4 or anti-mouse CD8 antibodies or their isotype controls are administered in 100 mL, i.p. at 2.5 mg/mL every 4 days, for a total of 4 injections per mouse (1 mg).

References:

[1]. X. Bao, et al. Combination of a Novel EP4 Antagonist E7046 and Radiation Therapy Promotes Anti-tumor Immune Response and Tumor Rejection in Preclinical Tumor Models. International Journal of Radiation Oncology Biology Physics
[2]. Diana I. Albu, et al. EP4 Antagonism by E7046 diminishes Myeloid immunosuppression and synergizes with Treg-reducing IL-2-Diphtheria toxin fusion protein in restoring anti-tumor immunity. OncoImmunology.