Sub-micron microparticles with tunable fluorescence emission obtained via co-self-assembly of amidoximed polymeric ligands and lanthanide ions.

Lanthanide coordinating polymeric microparticles have witnessed increasing research interests during the past decades due to their versatile morphology and tunable fluorescent properties. Herein, we have synthesized an amidoximed block copolymer containing aromatic backbone and pendent amidoxime as well as carboxyl groups, which has been employed as the ligand to sensitize the intrinsic fluorescence emission of lanthanide ions of Tb3+ and Eu3+. Furthermore, the lanthanide coordinating polymeric microparticles showing tunable green and red emission fluorescence have been prepared via the emulsion confinement co-self-assembly of amidoximed polymeric ligands with Tb3+ and Eu3+. It is found that both the fluorescence emission and sizes of obtained fluorescent microparticles can be easily modulated in a wide range by tuning concentration of polymers and lanthanide ions, as well as emulsion evaporation temperature. Thanks to their tunable sizes (250-900 nm), fluorescence emission as well as presence of surface active functional groups, the present fluorescent microparticles would find potential applications in in-vitro detection, optical encoding and devices.

Atp8a1 deletion increases the proliferative activity of hematopoietic stem cells by impairing PTEN function.

PURPOSE: The eukaryotic cell plasma membrane contains several asymmetrically distributed phospholipids, which is maintained by the P4-ATPase flippase complex. Herein, we demonstrated the biological effects and mechanisms of asymmetrical loss in hematopoietic stem cells (HSCs). METHODS: An Atp8a1 knockout mouse model was employed, from which the HSC (long-term HSCs and short-term HSCs) population was analyzed to assess their abundance and function. Additionally, competitive bone marrow transplantation and 5-FU stress assays were performed. RNA sequencing was performed on Hematopoietic Stem and Progenitor Cells, and DNA damage was assayed using immunofluorescence staining and comet electrophoresis. The protein abundance for members of key signaling pathways was confirmed using western blotting. RESULTS: Atp8a1 deletion resulted in slight hyperleukocytosis, associated with the high proliferation of HSCs and BCR/ABL1 transformed leukemia stem cells (LSCs). Atp8a1 deletion increased the repopulation capability of HSCs with a competitive advantage in reconstitution assay. HSCs without Atp8a1 were more sensitive to 5-FU-induced apoptosis. Moreover, Atp8a1 deletion prevented HSC DNA damage and facilitated DNA repair processes. Genes involved in PI3K-AKT-mTORC1, DNA repair, and AP-1 complex signaling were enriched and elevated in HSCs with Atp8a1 deletion. Furthermore, Atp8a1 deletion caused decreased PTEN protein levels, resulting in the activation of PI3K-AKT-mTORC1 signaling, further increasing the activity of JNK/AP-1 signaling and YAP1 phosphorylation. CONCLUSION: We identified the role of Atp8a1 on hematopoiesis and HSCs. Atp8a1 deletion resulted in the loss of phosphatidylserine asymmetry and intracellular signal transduction chaos.

Liver cancer stem cell dissemination and metastasis: uncovering the role of NRCAM in hepatocellular carcinoma.

BACKGROUND: Liver cancer stem cells (LCSCs) play an important role in hepatocellular carcinoma (HCC), but the mechanisms that link LCSCs to HCC metastasis remain largely unknown. This study aims to reveal the contributions of NRCAM to LCSC function and HCC metastasis, and further explore its mechanism in detail. METHODS: 117 HCC and 29 non-HCC patients with focal liver lesions were collected and analyzed to assess the association between NRCAM and HCC metastasis. Single-cell RNA sequencing (scRNA-seq) was used to explore the biological characteristics of cells with high NRCAM expression in metastatic HCC. The role and mechanism of NRCAM in LCSC dissemination and metastasis was explored in vitro and in vivo using MYC-driven LCSC organoids from murine liver cells. RESULTS: Serum NRCAM is associated with HCC metastasis and poor prognosis. A scRNA-seq analysis identified that NRCAM was highly expressed in LCSCs with MYC activation in metastatic HCC. Moreover, NRCAM facilitated LCSC migration and invasion, which was confirmed in MYC-driven LCSC organoids. The in vivo tumor allografts demonstrated that NRCAM mediated intra-hepatic/lung HCC metastasis by enhancing the ability of LCSCs to escape from tumors into the bloodstream. Nrcam expression inhibition in LCSCs blocked HCC metastasis. Mechanistically, NRCAM activated epithelial-mesenchymal transition (EMT) and metastasis-related matrix metalloproteinases (MMPs) through the MACF1 mediated ß-catenin signaling pathway in LCSCs. CONCLUSIONS: LCSCs typified by high NRCAM expression have a strong ability to invade and migrate, which is an important factor leading to HCC metastasis.

TSPAN32 suppresses chronic myeloid leukemia pathogenesis and progression by stabilizing PTEN.

We report herein that TSPAN32 is a key node factor for Philadelphia (Ph+) leukemia pathogenesis. We found that TSPAN32 expression was repressed by BCR-ABL and ectopic TSPAN32 expression upon Imatinib treatment inhibited the proliferation of Ph+ cell lines. Tspan32 overexpression significantly prevented BCR-ABL induced leukemia progression in a murine model and impaired leukemia stem cell (LSC) proliferation. LSCs represent an obstacle for chronic myeloid leukemia (CML) elimination, which continually replenish leukemia cells and are associated with disease relapse. Therefore, the identification of essential targets that contribute to the survival and self-renewal of LSCs is important for novel curative CML. Mechanistically, TSPAN32 was shown to interact with PTEN, increased its protein level and caused a reduction in PI3K-AKT signaling activity. We also found that TSPAN32 was repressed by BCR-ABL via the suppression of an important transcription factor, TAL1. Ectopic expression of TAL1 significantly increased TSPAN32 mRNA and protein level, which indicated that BCR-ABL repressed TSPAN32 transcription by decreasing TAL1 expression. Overall, we identified a new signaling axis composed of "BCR-ABL-TAL1-TSPAN32-PTEN-PI3K-AKT". Our findings further complement the known mechanisms underlying the transformation potential of BCR-ABL in CML pathogenesis. This new signaling axis also provides a potential means to target PI3K-AKT for CML treatment.

HDAC I/IIb selective inhibitor Purinostat Mesylate combined with GLS1 inhibition effectively eliminates CML stem cells.

Purinostat Mesylate (PM) is a novel highly selective and active HDAC I/IIb inhibitor, and the injectable formulation of PM (PMF) based on the compound prescription containing cyclodextrin completely can overcome PM's poor solubility and improves its stability and pharmacokinetic properties. Here, we showed that PM effectively repressed the survival of Ph+ leukemia cells and CD34+ leukemia cells from CML patients in vitro. In vivo studies demonstrated that PMF significantly prevented BCR-ABL(T315I) induced CML progression by restraining leukemia stem cells (LSCs), which are insensitive to chemotherapy and responsible for CML relapse. Mechanism studies revealed that targeting HDAC I/IIb repressed several important factors for LSCs survival including c-Myc, ß-Catenin, E2f, Ezh2, Alox5, and mTOR, as well as interrupted some critical biologic processes. Additionally, PMF increased glutamate metabolism in LSCs by increasing GLS1. The combination of PMF and glutaminase inhibitor BPTES synergistically eradicated LSCs by altering multiple key proteins and signaling pathways which are critical for LSC survival and self-renewal. Overall, our findings represent a new therapeutic strategy for eliminating LSCs by targeting HDAC I/IIb and glutaminolysis, which potentially provides a guidance for PMF clinical trials in the future for TKI resistance CML patients.

The suppressive functions of Rora in B lineage cell proliferation and BCR/ABL1-induced B-ALL pathogenesis.

RORA plays an important role in regulating circadian rhythms, inflammation, metabolism and cellular development. Herein, we explore the roles of Rora in B cell proliferation and differentiation, as well as in Ph+ B-ALL. By using Roraloxp/loxp Mx-1-Cre mice, Rora was deleted in hematopoietic cells post Pipc induction. Rora deficiency mice were associated with an obvious accumulation of B cells in the peripheral blood, bone marrow, and spleen. On the other hand, activation of Rora with Cholesterol sulfate (CS) was associated with decreased B cell numbers. RNA-seq analysis revealed that the transcription level of Lmo1 was decreased in Rora deficient B cells. Moreover, the expression of RORA was shown to be decreased in Ph+ B-ALL cells compared to peripheral blood derived B cells from healthy donors. The overexpression of Rora in BaF3 cells with BCR/ABL1 was also associated with impeded the cell growth and an increased apoptotic rate compared to cells transduced with BCR/ABL1 alone. The co-expression of BCR/ABL1 and Rora induced B-ALL mouse model was associated with the significant inhibition of BCR/ABL1-transformed cell growth and prolonged the survival of the diseased mice. These results suggest a novel role for Rora in B cell development and Ph+ leukemogenesis.

Targeting glutaminase1 and synergizing with clinical drugs achieved more promising antitumor activity on multiple myeloma.

Multiple myeloma (MM) pathogenesis remains incompletely understood and biomarkers predicting treatment response still remain lacking. Here we describe the rational mechanisms of combining targeting glautaminase1 (GLS1) with other chemo-reagents for MM treatment. Gls1 is highly expressed cMYC/KRAS12V-drived plasmacytoma (PCT) cells. Down-regulation of Gls1 with miRNAi in cMYC/KRAS12V-expressing BaF3 cells prevented them from growing independence of interleukin 3 (IL3). By using our cMYC/KRAS12V-transduced adoptive plasmacytoma mouse model, we found that Gls1 is involved in PCT pathogenesis. Down-regulation of Gls1 significantly prolonged the survival of PCT recipients. Knockdown of Gls1 increased the expression of Cdkn1a and Cdkn1b and decreased the expression of some critical oncogenes for cancer cell survival, such as c-Myc, Cdk4, and NfκB, as well as some genes which are essential for MM cell survival, such as Irf4, Prdm1, Csnk1α1, and Rassf5. Combination of Gls1 inhibition with LBH589, Bortezomib, or Lenalidomide significantly impaired tumor growth in a MM xenograft mouse model. Our data strongly suggest that Gls1 plays an important role for MM pathogenesis and that combination of GLS1 inhibitor with other MM therapy agents could benefit to MM patients.