Acute Acquired Metabolic Encephalopathy Based on Diffusion MRI

Metabolic encephalopathy is a critical condition that can be challenging to diagnose. Imaging provides early clues to confirm clinical suspicions and plays an important role in the diagnosis, assessment of the response to therapy, and prognosis prediction. Diffusion-weighted imaging is a sensitive technique used to evaluate metabolic encephalopathy at an early stage.Metabolic encephalopathies often involve the deep regions of the gray matter because they have high energy requirements and are susceptible to metabolic disturbances. Understanding the imaging patterns of various metabolic encephalopathies can help narrow the differential diagnosis and improve the prognosis of patients by initiating proper treatment regimen early.

Bortezomib inhibits the survival and proliferation of bone marrow stromal cells

BACKGROUND: Bortezomib is widely used for the treatment of multiple myeloma. Bone marrow stromal cells (BMSCs) endow myeloma cells with survival and growth advantages. However, the influence of bortezomib on BMSCs is not well elucidated. We examined the effects of bortezomib on the survival and growth of BMSCs in vitro. METHODS: The effects of bortezomib on the survival and proliferation of the BMSC MS-5 cell line and on BMSCs obtained from healthy individuals (N=4) and newly diagnosed myeloma patients (N=5) were investigated in vitro. Transmembrane cell migration was evaluated using the Transwell system. A short interfering RNA strategy was used to knock down the expression of chemokine (CXC motif) ligand 12 (CXCL12) mRNA. To examine the effects of bortezomib-exposed BMSCs on the migration and localization of myeloma cells, MS-5 monolayers were treated with bortezomib for 24 hr, washed, and then overlaid with human RPMI8226 myeloma cells. RESULTS: Bortezomib inhibited BMSC proliferation in a concentration-dependent manner, and induced cellular apoptosis. Bortezomib decreased CXCL12 production by BMSCs. Knockdown of CXCL12 mRNA in BMSCs revealed that CXCL12 served as an autocrine growth factor. Short-term bortezomib treatment of BMSC monolayers reduced the tendency of myeloma cells to locate to positions under the monolayers. CONCLUSION: Bortezomib inhibits the survival and growth of BMSCs via downregulation of CXCL12, which may contribute to the clinical effects of this agent.

Expression and functional roles of the chemokine receptor CXCR7 in acute myeloid leukemia cells

BACKGROUND: The C-X-C chemokine receptor 7 (CXCR7) has been shown to be a decoy receptor for CXCR4 in certain cell types. We investigated the expression status and functional roles of CXCR7 in acute myeloid leukemia (AML) cells in vitro. METHODS: CXCR7 mRNA was knocked down in AML cells by using small interfering RNA (siRNA) technology, and subsequent biological alterations in the cells were evaluated in vitro. RESULTS: All AML cell lines examined in this study (U937, K562, KG1a, HL-60, and MO7e) and primary CD34+ cells obtained from patients with AML expressed CXCR7 mRNA at various levels. Western blotting showed that all AML cells produced CXCR7. Furthermore, all AML cells expressed CXCR7 in both the cytoplasm and on the cell surface at various levels. Stromal cell-derived factor-1 (SDF-1; C-X-C motif ligand 12 (CXCL12)) induced internalization of cell surface CXCR7. However, neither hypoxia nor the examined hematopoietic growth factors (interleukin-1beta (IL-1beta), IL-3, IL-6, granulocyte-colony-stimulating factor, granulocyte, macrophage-colony-stimulating factor, and stem cell factor) and proinflammatory cytokines (interferon-gamma, transforming growth factor-beta, and tumor necrosis factor-alpha) were found to alter cell surface CXCR7 expression. The transfection of AML cells with CXCR4 siRNA, but not CXCR7 siRNA, significantly impaired the CXCL12-induced transmigration of the cells. The transfection of AML cells with CXCR7 siRNA did not affect the survival or proliferation of these cells. Knockdown of CXCR7, but not CXCR4, induced the upregulation of CXCL12 mRNA expression and CXCL12 production in AML cells. CONCLUSION: CXCR7 is involved in the regulation of autocrine CXCL12 in AML cells.

Differential effects of CXCR4 antagonists on the survival and proliferation of myeloid leukemia cells in vitro

BACKGROUND: Antagonists of CXC chemokine receptor 4 (CXCR4), including AMD3100, induce peripheral mobilization of hematopoietic stem cells and have been approved for clinical use. We explored whether the CXCR4 antagonists affected the survival and proliferation of myeloid leukemia cells in vitro. METHODS: The effects of CXCR4 antagonists AMD3100 and T140 on the survival and proliferation of myeloid leukemia cell lines (U937, HL-60, MO7e, KG1a, and K562) as well as CD34+ cells obtained from patients with AML and CML were analyzed by flow cytometry by using annexin V and a colorimetric cell proliferation assay. RESULTS: AMD3100, but not T140, stimulated the proliferation of leukemia cells in vitro in a dose-dependent manner for up to 5 days (~2-fold increase at a concentration of 10-5 M), which was not abrogated by pretreatment of the cells with pertussis toxin, but was attenuated by RNAi knockdown of CXCR7 transcripts. In contrast, AMD3100 induced a marked decrease in the cell numbers after 5-7 days. AMD3100, but not T140, induced phosphorylation of MAPK p44/p42. AMD3100 increased the number and size of leukemia cell colonies and reduced cell apoptosis during the first 5-7 days of incubation, but the phenomena were reversed during the later period of incubation. CONCLUSION: The effects of CXCR4 antagonists on the proliferation of myeloid leukemia cells are not uniform. AMD3100, but not T140, exerts dual effects, initially enhancing and subsequently inhibiting the survival and proliferation of the cells in vitro.

The CXCR4 Antagonist AMD3100 Has Dual Effects on Survival and Proliferation of Myeloma Cells In Vitro / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: AMD3100, an antagonist of the CXCR4 chemokine receptor is soon to be used clinically for the peripheral mobilization of hematopoietic stem cells (HSCs) in patients with multiple myeloma. AMD3100 has been shown to activate a G protein coupled with CXCR4 and thus acts as a partial CXCR4 agonist in vitro. Thus, we explored whether AMD3100 affected the survival and proliferation of myeloma cells in vitro. MATERIALS AND METHODS: The effects of AMD3100 on survival and proliferation of two myeloma cell lines (RPMI8226 and U266) as well as CD138+ cells obtained from several patients with multiple myeloma were analyzed by flow cytometry using annexin V and a colorimetric cell proliferation assay (CCK-8 assay). RESULTS: AMD3100, but not T140, another CXCR4 antagonist, stimulated the proliferation of myeloma cell lines and CD138+ primary human myeloma cells (-2-fold increase) in a dose-dependent manner in serum-free culture for up to 5 days, which was inhibited by pretreating the cells with pertussis toxin. AMD3100 enhanced the proliferation of U266 cells induced by interleukin-6 and partially reversed AG490-mediated growth inhibition and apoptosis induced by serum deprivation in RPMI8226 cells. AMD3100 induced the phosphorylation of Akt and MAPK p44/p42 in U266 cells and MAPK p44/p42 in RPMI8226 cells. In contrast, AMD3100 markedly increased the cell apoptosis and reduced the number of RPMI8226 cells after 5 to 7 days of culture under serum-free conditions. CONCLUSION: AMD3100 exerts dual effects, initially enhancing and subsequently inhibiting the survival and proliferation of myeloma cells, signaling via CXCR4 in vitro.

Stromal Cell-Derived Factor-1 Promotes Myeloma Cell Growth in Both Autocrine and Paracrine Manners

BACKGROUND: The question as to whether stromal cell-derived factor-1 (SDF-1) stimulated myeloma cell growth has been controversial. We explored the possibility that SDF-1 may function as an autocrine growth factor of myeloma cells. METHODS: CD138+ primary bone marrow myeloma cells and myeloma cell lines (RPMI8226, U266, and ARH77) were used. Chemotaxis in response to SDF-1 of the cells was analyzed using Transwells(TM). Cell proliferation was measured by a colorimetric assay. SDF-1 mRNA expression was analyzed by RT-PCR (reverse-transcription-polymerase chain reaction). SDF-1 and interleukin-6 (IL-6) receptor expression as well as signaling molecule phosphorylation levels, were examined using Western blot analysis. Concentrations of SDF-1 in the cell culture supernatants were measured by ELISA assay. RESULTS: SDF-1 alone had no discernible effect on the proliferation of CD138+ primary myeloma cells or myeloma cell lines. In contrast, SDF-1 significantly enhanced IL-6-induced proliferation of these cells. SDF-1 up-regulated the expression of IL-6 receptor and enhanced phosphorylation of AKT in an additive manner with IL-6. Co-culture of the myeloma cells with umbilical vein endothelial cells over-expressing the SDF-1 gene revealed that SDF-1 played an important role in not only the migration of the cells underneath the stromal cells but also the proliferation of the cells in contact with stromal cells. All the myeloma cell lines expressed SDF-1 mRNA, and SDF-1 was detected in the culture supernatants of the cells. The G protein-coupled receptor inhibitor, pertussis toxin, inhibited the proliferation of these cells in suspension cultures. CONCLUSION: SDF-1, most likely in concert with IL-6, enhanced the proliferation of myeloma cells in a both paracrine and autocrine manner.

Cytoplasmic Trapping of CXCR4 in Hepatocellular Carcinoma Cell Lines / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The chemokine receptor CXCR4 plays a role in the metastasis and progression of a broad range of malignant tumors; however, its influence on hepatocellular carcinoma (HCC) is not well defined. Thus, we analyzed the expression of CXCR4 and its functions in HCC cell lines in vitro. MATERIALS AND METHODS: Five HCC cell lines (HepG2, Hep3B, SK-HEP-1, NCI-H630 and PLC/PRF5) were investigated. The CXCR4 expression was analyzed by RT-PCR, Western blotting, flow cytometry and immunofluorescence staining. In addition, the effects of stromal cell-derived factor-1 (SDF-1) on the migration, proliferation and survival of the cells were investigated, as well as the SDF-1-induced phosphorylation of signaling molecules. RESULTS: All five cell lines had abundant CXCR4 in their cytoplasm, whereas a cell surface CXCR4 expression was only detected in a very small population of PLC/ PRF5 cells. In contrast, SDF-1 bound to all the cells. SDF-1 induced the phosphorylation of AKT and ERK1/2 in the PLC/PRF5 cells and the phosphorylation of Stat3, AKT and ERK1/2 in the Hep3B cells. Nonetheless, SDF-1 did not induce migration or proliferation in any of the cells, nor did it rescue the cells from serum deprivation-induced apoptosis. Recruitment of CXCR4 from the cytoplasm to the cell surface was not elicited by dexamethasone, proinflammatory cytokines or VEGF. Hypoxia increased both the cytoplasmic and cell surface expressions of CXCR4 in only the PLC/PRF5 cells. CONCLUSIONS: CXCR4 is trapped in the cytoplasm and it is not recruited to the cell surface by standard extrinsic stimuli in the majority of HCC cell lines, and the result of this is a negligible response to SDF-1.