Resveratrol (REV) is a naturally occurring phytoalexin that inhibits neuronal K⁺ channels; however, the molecular mechanisms behind the effects of REV and the relevant α-subunit are not well defined. With the use of patch-clamp technique, cultured cerebellar granule cells, and HEK-293 cells transfected with the K(v)2.1 and K(v)2.2 α-subunits, we investigated the effect of REV on K(v)2.1 and K(v)2.2 α-subunits. Our data demonstrated that REV significantly suppressed Kv2.2 but not Kv2.1 currents with a fast, reversible, and mildly concentration-dependent manner and shifted the activation or inactivation curve of Kv2.2 channels. Activating or inhibiting the cAMP/PKA pathway did not abolish the inhibition of K(v)2.2 current by REV. In contrast, activation of PKC with phorbol 12-myristate 13-acetate mimicked the inhibitory effect of REV on K(v)2.2 by modifying the activation or inactivation properties of Kv2.2 channels and eliminated any further inhibition by REV. PKC and PKC-α inhibitor completely eliminated the REV-induced inhibition of K(v)2.2. Moreover, the effect of REV on K(v)2.2 was reduced by preincubation with antagonists of GPR30 receptor and shRNA for GPR30 receptor. Western blotting results indicated that the levels of PKC-α and PKC-β were significantly increased in response to REV application. Our data reveal, for the first time, that REV inhibited K(v)2.2 currents through PKC-dependent pathways and a nongenomic action of the oestrogen receptor GPR30.

Curcumin inhibited AML cell survival and angiogenesis and induced chemosensitivity. Aberrant expression of FoxM1 induces AML cell survival and chemoresistance. Inactivation of FoxM1 contributes to curcumin-induced anti-leukemic effects. Curcumin together with FoxM1 targeting agents may be effective for AML therapy.

Aims: PGE₂ is one of the most abundant prostanoids in mammalian tissues, but its effect on neuronal receptors has not been well investigated. This study examines the effect of PGE₂ on GABA_A receptor currents in rat cerebellar granule neurons. Methods: GABA_A currents were recorded using a patch-clamp technique. Cell surface and total protein of GABA_A β1/2/3 subunits was carried out by Western blot analysis. Results: Upon incubation of neurons with PGE₂ (1 µM) for 60 minutes, GABA_A currents were significantly potentiated. This PGE₂-driven effect could be blocked by PKC or CaMKII inhibitors as well as EP1 receptor antagonist, and mimicked by PMA or EP1 receptor agonist. Furthermore, Western blot data showed that PGE₂ did not increase the total expression level of GABA_A receptors, but significantly increased surface levels of GABA_A β1/2/3 subunits after 1 h of treatment. Consistently, both PKC and CaMKII inhibitors were able to reduce PGE₂-induced increases in cell surface expression of GABA_A receptors. Conclusion: Activation of either the PKC or CaMKII pathways by EP1 receptors mediates the PGE₂-induced increase in GABA_A currents. This suggests that upregulation of postsynaptic GABA_A receptors by PGE₂ may have profound effects on cerebellar functioning under physiological and pathological conditions.

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DNA methyltransferase 3A (DNMT3A) is one of two human de novo DNA methyltransferases essential for the regulation of gene expression. DNMT3A mutations and deletions have been previously observed in acute myeloid leukemia (AML), myelodysplastic sydromes and myeloproliferative neoplasms. However, the involvement of DNMT3A in acute lymphoblastic leukemia (ALL) has rarely been reported. In the present study, PCR and direct sequencing was performed to analyze mutations of DNMT3A amino acid residue 882 in 99 acute leukemia patients, including 57 AML patients, 41 ALL patients and a single biphenotypic acute leukemia (BAL) patient. DNMT3A expression was detected in mono-nuclear cells of the bone marrow in these patients and in normal individuals using real-time quantitative polymerase chain reaction, and 17.5% (10/57) of AML patients were found to exhibit DNMT3A mutations. Four missense mutations were observed in the DNMT3A-mutated AML patients, including R882 mutations and a novel single nucleotide polymorphism resulting in the M880V amino acid substitution. However, the ALL and BAL patients were not found to exhibit DNMT3A mutations. The DNMT3A expression levels in the AML patients were significantly higher compared with those of the ALL patients or normal controls. The reduced expression levels of DNMT3A were associated with a significantly lower complete remission rate in the AML patients. However, in the ALL patients, no statistical significance was identified. The results of the present study indicate that DNMT3A may play varying roles in the regulation of DNA methylation in AML and ALL.