In carboplatin-resistant canine osteosarcoma cells (HMPOS-2.5R and HMPOS-10R), compound 13 and the atypical Grp78 inhibitor 14 (Figure 3, the celecoxib derivative OSU-03012, which binds directly to the Grp78 ATPase domain) still showed considerable activity (EC50 = 1.9–3.5 μM for 13 and 5.3–8.5 μM for 14), while the Hsp70 inhibitor 1 was distinctly less active against these resistant cells (EC50 = 25–30 μM) than against the parent HMPOS cells (EC50 = 1.8 μM) [75,76]. Here, HSPA5 is linked to osteosarcoma.