wogonoside and Leukemia--Myeloid--Acute

Decreasing bone marrow (BM) microvessel density and circulating angiogenic cytokine levels are promising strategies for the treatment of relapsed and resistant acute myeloid leukemia (AML). Previous studies have reported that wogonoside could inhibit the progression of AML and suppress angiogenesis in a solid tumor, but the correlation of these two effects was ignored. In this research, we determined whether wogonoside could inhibit angiogenesis in this hematologic malignancy. We found that wogonoside could inhibit tumor growth and progression, and prolong the survival of nude mice inoculated with U937/MDR. Besides, reducing BM angiogenesis might cause therapeutic effect against resistant AML. Therefore, coculture between AML cells and BM stromal cells was established to imitate their crosstalk. Then, the effect of wogonoside on BM angiogenesis was tested in vitro and in vivo. We found that wogonoside could suppress microvessel formation in the chicken chorioallantoic membrane assay model and matrigel plug assay. The mechanism research revealed that wogonoside could block the JAK2-STAT3 pathway in AML cells and stromal cells to break their positive feedback. We detected several cytokines related to AML or angiogenesis and found that secreted interleukin-8 was a significant angiogenic cytokine to induce BM angiogenesis. These findings supported that new diagnostics and promising treatment strategies could be developed in relapsed and resistant AML patients.

Topics: Angiogenesis Inhibitors; Animals; Bone Marrow; Chick Embryo; Chorioallantoic Membrane; Coculture Techniques; Female; Flavanones; Glucosides; Humans; Interleukin-8; Janus Kinase 2; Janus Kinase Inhibitors; Leukemia, Myeloid, Acute; Mice, Inbred BALB C; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Neovascularization, Pathologic; Neovascularization, Physiologic; Paracrine Communication; Signal Transduction; STAT3 Transcription Factor; Stromal Cells; Tumor Cells, Cultured; U937 Cells; Xenograft Model Antitumor Assays

Acute myeloid leukaemia (AML) comprises a range of disparate genetic subtypes, involving complex gene mutations and specific molecular alterations. Post-translational modifications of specific proteins influence their translocation, stability, aggregation and even leading disease progression. Therapies that target to post-translational modification of specific proteins in cancer cells represent a novel treatment strategy. Non-homogenous subcellular distribution of PLSCR1 is involved in the primary AML cell differentiation. However, the nuclear translocation mechanism of PLSCR1 remains poorly understood. Here, we leveraged the observation that nuclear translocation of PLSCR1 could be induced during wogonoside treatment in some primary AML cells, despite their genetic heterogeneity that contributed to the depalmitoylation of PLSCR1 via acyl protein thioesterase 1 (APT-1), an enzyme catalysing protein depalmitoylation. Besides, we found a similar phenomenon on another AML-related protein, N-RAS. Wogonoside inhibited the palmitoylation of small GTPase N-RAS and enhanced its trafficking into Golgi complex, leading to the inactivation of N-RAS/RAF1 pathway in some primary AML cells. Taken together, our findings provide new insight into the mechanism of wogonoside-induced nuclear translocation of PLSCR1 and illuminate the influence of N-RAS depalmitoylation on its Golgi trafficking and RAF1 signalling inactivation in AML.

Topics: Cell Differentiation; Cell Line, Tumor; Cell Nucleus; Flavanones; Glucosides; Golgi Apparatus; GTP Phosphohydrolases; Humans; Leukemia, Myeloid, Acute; Lipoylation; Membrane Proteins; Phospholipid Transfer Proteins; Protein Transport; Thiolester Hydrolases; Tumor Cells, Cultured

Topics: Active Transport, Cell Nucleus; Animals; Calcium; Calcium Signaling; Cell Differentiation; Cell Nucleus; Female; Flavanones; Glucosides; Humans; Inositol 1,4,5-Trisphosphate Receptors; Leukemia, Myeloid, Acute; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Proteins; Phospholipid Transfer Proteins; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

Wogonoside is the main flavonoid component derived from the root of Scutellaria baicalensis Georgi. It is a popular Chinese herbal medicine with the potential to treat hematologic malignancies. In this study, we investigated the anticancer effects of wogonoside in acute myeloid leukemia (AML) cell lines and primary patient-derived AML cells. Wogonoside exerted antiproliferative properties both in vitro and in vivo. Furthermore, it efficiently inhibited the proliferation of U937 and HL-60 cells through the induction of G1 phase arrest and the promotion of differentiation. We also demonstrated that wogonoside significantly increased the transcription of phospholipid scramblase 1 (PLSCR1) due to its influence on the expression of cell cycle- and differentiation-related genes, including the upregulation of p21waf1/cip1 and downregulation of the oncogenic protein c-Myc. Wogonoside also promoted PLSCR1 trafficking into the nucleus and facilitated its binding to the inositol 1,4,5-trisphosphate receptor 1 (IP3R1) promoter, thus increasing the expression of IP3R1. Finally, inhibition of PLSCR1 expression with small interfering RNA partially blocked wogonoside-induced cell cycle arrest and differentiation and disturbed the wogonoside-associated molecular events. The results of this study therefore suggest that wogonoside may represent a therapeutic candidate for the treatment of AML.

Topics: Active Transport, Cell Nucleus; Animals; Antineoplastic Agents; Cell Cycle Checkpoints; Cell Differentiation; Cell Nucleus; Flavanones; Gene Expression Regulation, Leukemic; Glucosides; HL-60 Cells; Humans; Leukemia, Myeloid, Acute; Mice; Mice, Inbred BALB C; Mice, Nude; Mice, SCID; Phospholipid Transfer Proteins; Protein Transport; Tissue Distribution; U937 Cells; Xenograft Model Antitumor Assays