To test whether this JMN3-003-induced arrest is permanent or temporary, we next incubated cells in the presence of compound or vehicle alone for 30 hours, followed by removal of the substance and reseeding of cells at identical densities. Monitoring cell growth over an additional 72-hour incubation period in the absence of JMN3-003 revealed that proliferation rates resumed those of untreated control cells after removal of the compound (figure 4C), indicating reversibility of the growth arrest.