Discovery Of Novel GPR132 Agonist And Its Application For The Treatment Of Acute Myeloid Leukemia

Acute myeloid leukemia(AML)is a hematologic malignancy with high heterogeneity and aggressivity.Differentiation therapy is only successful in a small subset of AML patients.The five-year survival rate of AML is less than 30%,underlining the great need for targeting of alternative differentiation mechanisms.G-protein coupled receptors(GPCR)play a key role in a variety of physiological and pathological processes,representing the most important drug target families.In this study,we focused on the exploring the role of orphan GPCR in AML cell differentiation.Cancer genomics analysis revealed that orphan GPCRs are widely expressed in AML and are involved in regulating the development of AML.Orphan GPR132 is specifically expressed in myeloid cells,and its high expression is associated with a better prognosis of AML,suggesting that GPR132 is a potential therapeutic target for AML.Via biological experimental validation,we show that genetic activation of GPR132 significantly induced cell differentiation and suppressed cell growth of AML in vivo and in vitro,suggesting that GPR132 is a novel myeloid differentiation trigger.To further explore the therapeutic role of GPR132 signaling pathway in AML,we identified a novel and highly effective GPR132 agonist,8-Gingerol,through a series of GPCR screening systems such as Tango and Nano Bit.8-Gingerol is a bioactive component of ancient medicinal plant ginger with an EC₅₀ of 0.30?M on GPR132.Through flow cytometry,NBT reduction and Wright-Giems analysis,we found that GPR132 activation by 8-Gingerol could induce cell differentiation as reflected by significantly up-regulated expression of CD11b,enhanced energy metabolism level,and increased morphological maturation of AML cells.The proliferation ability of AML cells also can be weakened by 8-Gingerol in clone formation assay.Moreover,the pro-differentiation activity of was observed across a panel of AML cell lines with dictinct genetic mutations.Further mechanism study showed that 8-Gingerol inhibited the mammalian target of rapamycin(mTOR)signaling pathway by activating the GPR132-G_s-PKA pathway in AML cells.8-Gingerol combined with mTOR inhibitor could cooperatively induce AML cell differentiation in vitro.More importantly,we confirmed that 8-Gingerol alone or in combination with mTOR inhibitor can significantly suppress tumor growth and improve the survival of AML-bearing mice.In summary,our study have indicated that GPR132 is a potential drug target for differentiation induction therapy in AML,and identified 8-Gingerol as a novel GPR132 agonist.Furthermore,we explored the underlying mechanism that8-Gingerol control myeloid differentiation by GPR132-G_s-PKA-mTOR signaling axis,and confirmed the therapeutic effect of 8-Gingerol alone or in combination with mTOR inhibitor in AML mice model.Together,our study demonstrates that pharmacological activation of orphan GPR132 represent a potential strategy for inducing myeloid normal differentiation to treat patients with refractory AML.