Application of MRI Water-Fat Separation Technology in Patients with Multiple Myeloma / 中国实验血液学杂志

OBJECTIVE@#To explore the clinical significance of magnetic resonance imaging water-fat separation (Dixon) technique in patients with multiple myeloma.@*METHODS@#A total of 41 newly diagnosed patients with multiple myeloma who underwent Dixon in The Affiliated Hospital of Qingdao University from April 2019 to April 2021 were included in this study. Patients were divided into observation group and control group according to whether Dixon performance was normal or not. The differences of clinical data and fat fraction (FF) between the two groups were compared. The correlation between FF and clinical data, disease stages and differences before and after treatment were also compared. The receiver operator characteristic curve of patients was drawn to analyze the diagnostic value of FF combined with serum alkaline phosphatase for bone destruction in patients with multiple myeloma.@*RESULTS@#Among the 41 patients, there were 12 cases in the control group and 29 cases in the observation group. There was no significant difference in age and sex between the two groups. In the observation group, β2-microglobulin concentration and M protein were significantly higher than those in the control group, while serum alkaline phosphatase and FF were lower (P<0.05). In all 41 patients included in the study, there was a significant negative correlation between FF value and β2-microglobulin concentration (r=-0.57), and a significant positive correlation between FF value and serum alkaline phosphatase (r=0.31). After treatment, FF value increased, while myeloma cell percentage, β2-microglobulin concentration and M protein decreased in 11 patients who completed 4 cycles of chemotherapy, and the differences before and after treatment were statistically significant (P<0.05). The value of serum alkaline phosphatase combined with FF value in predicting bone destruction is higher than that of FF value or serum alkaline phosphatase alone.@*CONCLUSION@#Dixon's different imaging manifestations can reflect the severity of the disease. FF value is correlated with clinical examination results and R-ISS staging, and there is a significant difference before and after treatment. Serum alkaline phosphatase combined with FF value is better than two indicators alone in predicting bone destruction.

Effect of 5-aza-2'-deoxycytidine combined with trichostatin A on RPMI-8226 cell proliferation, apoptosis and DLC-1 gene expression / 中国实验血液学杂志

This study was aimed to investigate the effects of the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) and histone deacetylase inhibitor trichostatin A (TSA) on DLC-1 gene transcription regulation and molecular biological behaviours in the human multiple myeloma RPMI-8226 cells. The cells were treated respectively with 5-Aza-CdR and TSA alone, or the both combination; the cell proliferation and apoptosis, DLC-1 expression, the protein expression of Ras homolog family member A (RhoA) and Ras-related C3 botulinum toxin substrate 1 (Rac1) were examined by CCK-8 method, RT-PCR and ELISA, respectively. The results showed that the 5-Aza-CdR and TSA had cell growth inhibitory and apoptosis-inducing effects in dose-dependent manner (P < 0.05). Compared with a single drug (5-Aza-CdR or TSA alone), the effects were significantly enhanced after treatment with the combination of 5-Aza-CdR and TSA (P < 0.05). DLC-1 was weakly expressed in the control group; the treatment with 5-Aza-CdR alone enhanced its re-expression dose-dependently (P < 0.05). Compared with 5-Aza-CdR alone, 5-Aza-CdR plus TSA enhanced DLC-1 re-expression significantly.Compared with the control, 5-Aza-CdR and TSA significantly decreased RhoA and Rac1 protein expression (P < 0.05). It is concluded that 5-Aza-CdR and TSA can effectively reverse DLC-1 expression of RPMI-8226 cells; TSA has a synergistic effect on its re-expression. 5-Aza-CdR and TSA have significant cell growth inhibitory and apoptosis-inducing effects on RPMI-8226 cells. These effects may be related to the inhibition of Rho/Rho kinase signalling pathway.

Effects of HOXB4-transfecting directly and HOXB4-transfected HUCMSC on in vitro expansion of human umbilical cord blood CD34+ cells / 中国实验血液学杂志

This study was purposed to investigate the difference of nucleated cell (NC) count, CD34(+) cell ratio and expansion multiple, cell cycle and colony formation capability in in vitro expanded human umbilical cord blood CD34(+) cells from HOXB4-transfecting directly and HOXB4-transfected human umbilical cord mesenchymal stem cells (HUCMSC) by means of prepared feeder layers of HUCMSC. The HUCMSC were divided into 2 groups:first group, in which HOXB4 gene was transfected into HUCMSC by using lentiviral vecfor, and feeder layers were set up; and second group in which feeder layers for HUCMSC of non-transfected HOXB4 gene were set up. The CD34(+) cells were separated from HUCB by magmatic activated cell sorting(MACS). After culture in medium with cytokines for 2 days, CD34(+) cells were divided into 5 groups, including control group and experimental group. The control groups included CD34(+) cells as group A (blank control group) and GFP-CD34(+) cells as group B (negative control group) and experimental groups included HOXB4-CD34(+) cells as group C, HUCMSC+CD34(+) cells as group D, HOXB4-HUCMSC+ CD34(+) cells as group E and cells in all groups were cultured in vitro. The number of nucleated cells were counted at day 6, 10, 14 of culture and CD34 immunophenotypes, cell cycle and colony forming capability were measured at day 10 of culture in different conditions. The results indicated that HOXB4 gene could be transfected into HUCMSC by lentiviral vector and feeder layers were set up successfully. After culture for 14 days, the nucleated cells in 5 groups could be amplified effectively, and the expansion levels in 5 groups were in order HOXB4-HUCMSC+CD34(+) cell group> HOXB4-CD34(+) cell group>HUCMSC+CD34(+) cell group> control groups (P < 0.05). At day 10 of in vitro expansion the CD34(+) cell percentage decreased significantly in all groups, while the number of CD34(+) cell increased in experiment groups, which were in order HOXB4-CD34(+) cells group> HOXB4-HUCMSC+CD34(+) cell group>HUCMSC+CD34(+) cell group>control groups (P < 0.05). The cell cycle detection showed that the percentage of cells in S+G2/M phase in experiment groups were higher than that in control groups (P < 0.05), and percentage of cells in HOXB4-HUCMSC+CD34(+) cells group was higher (41.57%) than that in HOXB4-CD34(+) cells group(37.87%) and HUCMSC+CD34(+) cell group (28.65%) (P < 0.05). There was no statistical difference in the CFU number between HOXB4-HUCMSC+CD34(+) cell group and HOXB4-CD34(+) cell group, which were both higher than that in HUCMSC+CD34(+) cell group and control groups (P < 0.05).It is concluded that the CD34(+) cells cultured on HOXB4-HUCMSC feeder layers can be amplified significantly and kept the characteristics of stem cells, The feeder lager of HOXB4-HUCMSC is relative safe for amplification of CD34(+) cells in vitro, it possesses the potential useful value.

Construction of lentivirus vector containing human homeobox gene HOXB4 and its expression in human umbilical cord mesenchymal stem cells / 中国实验血液学杂志

This study was purposed to construct lentivirus vector containing human homeobox gene HOXB4 and explore changes of human umbilical cord mesenchymal stem cells (HUCMSC) after infected with HOXB4 mediated by lentivirus. PCR amplification was performed to obtain HOXB4, which was cloned in lenti-shuttle vector. Four-plasmid lentivirus packaging system was used to transfect HEK293T cells. After 48 h, lentivirus Lenti-HOXB4 was harvested and lentivirus titer was determined. Lenti-HOXB4 was used to infect HUCMSC. The infected cells were observed under inverted fluorescence microscope to determine the optimal multiplicity of infection (MOI). Meanwhile, RT-PCR, immune fluorescence staining, CCK-8 and flow cytometry (FCM) were used to determine the expression of HOXB4 and its effect on cell growth. The results indicated that lenti-HOXB4 was successfully obtained by co-transfecting the 293T cells with four plasmids. The determined virus titer was 3×10(8) TU/ml; when MOI was 20. Lenti-HOXB4 had a high transfection rate in HUCMSC, over 80%. In HUCMSC infected with lenti-HOXB4, the expression of target gene could be detected both at mRNA and protein levels. It could promote the proliferation of HUCMSC. FCM results indicated HOXB4 gene did not significantly influence the surface marker of HUCMSC. It is concluded that HOXB4 gene can promote the high proliferation of HUCMSC and does not significantly influence the expression of the surface marker of HUCMSC.

Thapsigargin-induced apoptosis of K562 cells and its mechanism / 中国实验血液学杂志

The aim was to study the apoptotic induction effect of thapsigargin on leukemia cell line K562 and its possible mechanism. After the treatment of leukemia cell line K562 by thapsigargin, morphological change of apoptotic cells was investigated by AO/EB fluorescent staining under fluorescent microscope; apoptosis rate was determined with annexin V-FITC/PI double staining by flow cytometry; intracellular calcium concentrations ([Ca(2+)]i) were measured by fluorescence spectrophotometer with calcium sensitive fluorescence indicator Fura-2/AM; mitochondrial transmembrance potentials (Delta Psi m) was detected on flow cytometry through staining of Rhodamine (Rh123); the changes of caspase-3, -7, -9, -12, cytochrome C, GRP78 proteins were detected by Western blot. The results showed that K562 cells cultured in 4 micromol/L thapsigargin for 48 hours exhibited typical morphological changes of apoptotic cells under fluorescent microscope, including shrinkage of cell, condensation of chromatin, breakage of nuclear, formation of apoptotic bodies, fluorescence of yellow green and pellet observed in early apoptoyic cells and hyacinth fluorescence of chromatin showed in late apoptotic cells. 24 and 48 hours after exposure to 1, 2, 4, 8 micromol/L thapsigargin, the apoptotic rates of K562 were respectively 7.51%, 11.65%, 23.22%, 30.56% and 12.85%, 20.27%, 31.51%, 44.16%, in dose-dependent manner, and were statistically significant when compared with the controls (P < 0.05). The apoptotic rate of K562 was dose- and time-dependent in experiment range. The enhancement of [Ca(2+)]i and the decrease of the Delta Psi m in K562 cells were induced by thapsigargin and were dose-dependent in experiment range, compared with control, P < 0.05. Western blot results indicated that cleavage and activation of caspase-3, -7, -9, -12, releasing of cytochrome C from mitochondria, upregulation of GRP78 expression at the endoplasmic reticulum were induced in K562 cells after 24 hours exposure of 4 micromol/L thapsigargin. It is concluded that thapsigargin induces endoplasmic reticulum stress-induced apoptosis in K562 cells. Endoplasmic reticulum is a novel important initiatory site of apoptosis in cells; the cleavage and activation of caspase-3, -7, -9, -12 play very important role in endoplasmic reticulum stress-induced apoptosis of K562 cells and is one of the important mechanisms for thapsigargin-induced apoptosis. Thapsigargin-induced apoptosis in K562 cells is associated closely with the disruption of the Delta Psi m and the release of cytochrome C from mitochondria, mitochondria participates in endoplasmic reticulum stress-induced apoptosis in K562 cells.

Expression and significance of melanoma antigen gene-3 in endoplasmic reticulum stress-induced apoptosis of K562 cells / 中国实验血液学杂志

This study was aimed to explore the expression and significance of melanoma antigen gene-3 (MAGE-3) in endoplasmic reticulum stress-induced apoptosis. After the treatment of leukemia cell line K562 and its multidrug-resistant cell line K562/A02 by thapsigargin, intracellular calcium concentrations ([Ca(2+)]i) in K562 and K562/A02 were measured by fluorescence spectrophotometer with calcium sensitive fluorescence indicator Fura-2/AM; expression changes of glucose-regulated protein 78 (GRP78) were detected by Western blot; morphological change of apoptotic cell was investigated by AO/EB fluorescent staining under fluorescent microscope; apoptosis rate was determined by terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick end labelling (TUNEL) staining; the expression of MAGE-3 gene mRNA was detected by RT-PCR. The results showed that (1) thapsigargin induced the enhancement of [Ca(2+)]i with different extent in K562 and K562/A02 cells, and the enhancement of [Ca(2+)]i was dose-dependent in experiment range. At the same time, thapsigargin induced upregulation of GRP78 protein expression and typical apoptotic changes of K562 and K562/A02 cells, apoptotic rate was also dose-dependent in experiment range. The [Ca(2+)]i in K562/A02 cells were higher than that in K562 cells. (2) in the course of endoplasmic reticulum stress-induced apoptosis by thapsigargin, the expression of MAGE-3 gene mRNA was remarkably downregulated. Moreover, the expression of MAGE-3 gene mRNA in K562/A02 cells was higher than that in K562 cells. It is concluded that (1) thapsigargin induces endoplasmic reticulum stress-induced apoptosis of K562 and K562/A02 cells in experiment range, and this may be associated with downregulation of MAGE-3 mRNA expression or MAGE-3 gene may participates in the regulation of endoplasmic reticulum stress-induced apoptosis. (2) MAGE-3 gene may possess anti-apoptotic activity, multidrug resistance in K562/A02 cells can be associated with [Ca(2+)]i increase and upregulation of MAGE-3 expression.

Expression of BLM mRNA in six tumor cell strains / 中国实验血液学杂志

The mutations of BLM gene may result in Bloom's syndrome which includes immunodeficiency, predisposition to malignant tumors and so on, and enhances sister chromati exchange (SCE), DNA replication failure, genome instability, and increases cancer susceptibility. This study was aimed to investigate the variability of mRNA expression level and cDNA structure of BLM gene in tumor cell strains so as to look for a new cancerogenic mechanism and to find a new therapeutic target. The expression level of mRNA and the structure of cDNA of BLM gene in six tumor cell strains and the normal human bone marrow mononuclear cells were detected with RT-PCR and DNA sequencing was performed. The results indicated that these tumors cells expressed BLM mRNA higher than the normal human bone marrow mononuclear cells (P < 0.01), but no cDNA sequence abnormality of BLM gene in these tumors cells was observed. It is concluded that the increase of expressing level of BLM mRNA may play an important role in the development of these tumors.