[The anti-proliferative and anti-inflammatory mechanisms of JAK1 inhibitor SHR0302 versus Ruxolitinib in SET2 cell line and primary cells].

Objective: To explore the effects and molecular mechanism of the selective JAK1inhibitor SHR0302 and Ruxolitinib on myeloproliterative neoplasms (MPN) cell line SET2 and primary cells in vitro. Methods: Cell proliferation was detected by CCK8 kit. Colony forming experiment was conducted to evaluate erythroid burst colony formation unit (BFU-E) of primary cells from MPN patients. Multi-factor kits were used to detect six inflammatory cytokines. Phosphorylated proteins of Jak-Stat signaling pathway were tested by Western blot. Results: At different time points after treated with SHR0302 and Ruxolitinib, the inhibition of cell proliferation was dose dependent by both drugs (P<0.01) . The inhibitory rates of 2.5 μmol/L SHR0302 and 0.1 μmol/L Ruxolitinib on SET2 cells for 72 h were comparable, i.e. (59.94±0.60) % and (64.00±0.66) %, respectively, suggesting that the inhibitory effect of SHR0302 was weaker than that of Ruxolitinib. Similarly, both SHR0302 and Ruxolitinib inhibited BFU-E in primary marrow cells from MPN patients in a dose-dependent manner. SHR0302 1.0 μmol/L produced similar degree of inhibition compared to Ruxolitinib 0.2 μmol/L. Except IL-12, the expression of other 5 cytokines (IL-6, TNF-α, IL-1β, IL-2, IL-8) was significantly inhibited by 1.6 μmol/L SHR0302 in SET2 cells at 24 h (P<0.01) , while Ruxolitinib 1.0 μmol/L had the same effect. Several phosphorylated molecules of Jak-Stat signaling pathway were significantly inhibited by SHR0302 in SET2 cells only for 3 h. P-stat1 (Tyr701) , p-stat3 (Tyr705) were down-regulated when treated with SHR0302 1.0 μmol/L (P<0.05) , p-jak1 (tyr1022/1023) and p-stat5 (Tyr694) were inhibited at 5.0 μmol/L (P<0.05) . Ruxolitinib significantly inhibited the downstream STAT protein at 0.1 μmol/L. Again, the inhibitory effect of SHR0302 on protein expression was weaker than that of Ruxolitinib. Conclusion: SHR0302 can effectively inhibit the proliferation of MPN cell line and patients' primary cells, as well as the expression of inflammatory factors. The molecular mechanism is possibly related to the down-regulation of phosphorylated proteins of Jak-Stat signaling pathway. Overall, the anti-proliferative and anti-inflammatory effects of SHR0302 are weaker than those of Ruxolitinib.