Relationship between V617F mutation and 46/1 haplotype in JAK2 gene in patients with chronic myeloproliferative diseases and frequencies of 46/1 haplotype in different Chinese nationalities / 中国实验血液学杂志

Somatic gene V617F mutation in JAK2 is a critical molecular and biological indicator to diagnosis of chronic myeloproliferative disease (MPD). This study was aimed to investigate the genetic background of V617F mutation in 46/1 gene haplotype in Chinese MPD patients, and the frequencies of 46/1 gene haplotype and V617F mutation in three nationalities of Chinese populations. Peripheral blood or bone marrow samples of 150 V617F mutation positive MPD patients, 123 V617F mutation negative MPD patients, 124 healthy Han individuals, 395 healthy Tibetan individuals and 315 healthy Yugu individuals were collected. The allele-specific multiplex PCR method was established, the presence or absence of V617F mutation, the presence or absence of 46/1 haplotype, and the relationship between V617F and 46/1 haplotype were easily identified by agarose gel image. The results showed that the V617F mutation located in the 46/1 haplotype of 88 cases (58.67) among 150 V617F-positive MPD cases. In 814 Chinese healthy individuals including Han, Tibetan, Yugu nationalities, the frequency of the 46/1 gene haplotype was 38.37 without difference in the frequency among different nationalities, and no V617F mutation was found in Chinese healthy populations, The frequency of the 46/1 gene haplotype was 43.09 in V617F mutation negative MPD patients and was 69.33 in V617F mutation positive MPD patients, the latter was obviously higher than former and than that in healthy Han individuals. In conclusion, a multiplex PCR method has been developed that is simple and useful to identify V617F mutation in JAK2 gene and its relationship to the 46/1 haplotype. In more than half of Chinese V617F-positive MPD patients, the V617F mutation locates in 46/1 haplotype in JAK2. The frequencies of 46/1 haplotype are statistically insignificant among Han, Tibetan and Yugu nationality populations.

A1381T and -1793G/C polymorphisms of vWF gene impact the plasma vWF levels in Yugur, Tibetan and Han nationalities of China / 中国实验血液学杂志

The aim of this study was to investigate the similarities and differences of A1381T (rs216311) and -1793G/C (rs7966230) single nucleotide polymorphisms (SNP) in Chinese Yugur, Tibetan, and Han nationalities and their influence on plasma vWF concentration in order to explore the sensitivity of these 3 nationalities to vWF-related diseases. Peripheral venous blood was obtained from 322 Yugur, 399 Tibetan, and 120 Han healthy people. The DNA were then extracted. vWF gene A1381T and -1793G/C polymorphisms were analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequenced when it was necessary. The vWF:Ag level in plasma was determined by ELISA. The results showed that the genotype distribution of vWF gene at both A1381T and -1793G/C loci in Yugur, Tibetan and Han nationalities was different with statistically significance (P < 0.05). GG genotype of A1381T locus accounted for 69.9% in Yugur nationality, which was much higher than 56.6% and 53.3% in Tibetan and Han nationalities respectively(P < 0.01); AA genotype of A1381T locus expressed a low level of vWF in plasma. For the -1793G/C locus, the proportion of CG genotype in Yugur was much higher than that in Han, CC genotype expressed a high level of vWF in plasma. The plasma vWF levels with different nationalities and the polymorphism of vWF gene were significantly different. It is concluded that the polymorphisms of vWF gene at both A1381T and -1793G/C loci in Yugur, Tibetan and Han are significantly different; the polymorphism of vWF gene influences the plasma vWF level; the plasma vWF levels in Yugur and Tibetan are significantly higher than that in Han, which may be associated with the living environment and habits.

Effects of ICAM-1 gene K469E, K56M polymorphisms on plasma sICAM-1 expression levels in Chinese Yugur, Tibetan and Han nationalities / 中国实验血液学杂志

This study was purposed to investigate the intercellular cell adhesion molecule-1 (ICAM-1) gene K469E (A/G) (rs5498) and K56M (A/T) (rs5491) single nucleotide polymorphisms (SNP) and soluble ICAM-1 (sICAM-1) levels in plasma in three Chinese populations of Yugur, Tibetan and Han nationalities, to analyze comparatively the genotypes and allele frequencies distribution in different ethnic groups, and to explore the effects of ICAM-1 K469E and K56M polymorphism and sICAM-1 levels in plasma. EDTA-anticoagulant venous blood from Yugur(327 cases), Tibetan (400 cases) and Han (126 cases) people was collected, the DNA was extracted by using whole blood genomic DNA extraction kit, DNA SNP were analyzed by PCR-RFLP, genotype was judged by gel scan imaging system after agarose gel electrophoresis, the gene sequence was determined and the distribution of ICAM-1 genotypes and allele frequencies were compared among different ethnic groups, besides, the group representativeness was tested via the Hardy-Weinberg genetic equilibrium. Finally, the human sICAM-1 plasma levels were detected by using human ICAM-1 ELISA kit. The results showed that DNA sequencing result was consistent with PCR-RFLP analysis. In Yugur, Tibetan and Han nationalities, the KK, KE and EE three genotypes at ICAM-1 K469E gene locus were detected, the genotype distribution was not statistically significantly different, while the K, E allele frequency distribution was statistically significantly different (P < 0.05). Both of genotype and allele frequency distribution between Yugur, Tibetan and Han nationalities were statistically significantly different (P < 0.05). In K56M site only KK, KM two genotypes were detected, but the MM genotype was not detected in the three ethnic groups; the difference of two genotypes and K, M allele frequencies between Yugur and Han population was statistically significantly different (P < 0.05). Among three ethnic groups, the sex ratio and age distribution of K469E, K56M genotypes and allele frequencies of ICAM-1 gene were not significantly different, and distribution was in accordance with Hardy-Weinberg genetic equilibrium (P > 0.05). The plasma sICAM-1 level at ICAM-1 K469E allele locus in K individuals [(253 ± 122), (185 ± 97) µg/L] was higher than that at non-K allele [(145 ± 110) µg/L, P < 0.01]; the plasma sICAM-1 level of ICAM-1 K56M sites with KK genotype [(253 ± 122) µg/L] was higher than that of the KM genotypes [(168 ± 103) µg/L, P < 0.01]. In Yugur and Tibetan groups, the plasma sICAM-1 levels [(224 ± 80), (214 ± 111) µg/L] were higher than that in the Han group [(175 ± 125)µg/L, P < 0.05]. Pairwise comparison indicated that the plasma sICAM-1 levels between Yugur and Han group were statistically significantly different (P < 0.01), that was significantly different between Tibetan and Han group (P < 0.05). It is concluded that in Yugur, Tibetan and Han population, the genotypes and gene frequencies of two amino acid sites K469E and K56M in ICAM-1 were KK/KE-type, KK-type and K allele, moreover, the ratio of them in Yugur and Tibetan group was higher than that in Han, while there is not significant difference in sex ratio and age distribution, therefore, ICAM-1 genotype and allele frequency distribution in this study had ethnic representativeness. ICAM-1 gene K469E and K56M polymorphisms were likely to affect the plasma sICAM-1 expression level. K469E gene K allele may be a genetic risk factor, while K56M gene M allele a may be genetic protective factor for some diseases.

Arsenic trioxide inhibits P-glycoprotein expression in multidrug-resistant human leukemia K562/ADM cell line that overexpresses mdr-1 gene and enhances their chemotherapeutic sensitivity / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of arsenic trioxide (As(2)O(3)) on the apoptosis and P-glyco-protein (P-gp) expression of multidrug-resistant human leukemia K562/ADM cells, and the combined effects of As(2)O(3) with conventional chemotherapeutic agents.</p><p><b>METHODS</b>Multidrug-resistant human leukemia cell line K562/ADM that overexpresses mdr-1 gene was used as the target cells. The cell proliferating activity was assessed with a MTT assay. Cell morphology was examined by light microscopy, confocal microscopy and electron-microscopy. P-gp expression, cell-cycle status were determined by flow cytometry.</p><p><b>RESULTS</b>K562/ADM cells were highly resistant to adriamycin, and cross-resistant to daunorubicin and etoposide. As(2)O(3) at concentrations of 0.5 to 20 micromol/L inhibited the proliferation of K562/ADM cells, and K562/ADM cells were more sensitive to As(2)O(3) than their parent K562 cells did. As(2)O(3) induced marked apoptosis of K562/ADM cells showed by typical apoptotic morphological changes and the appearance of high sub-G(1) cell population. As(2)O(3) significantly inhibited the P-gp expression in K562/ADM cells, and exerted a synergistic effect on the enhancement of the cell sensitivity to adriamycin, daunorubicin and etoposide.</p><p><b>CONCLUSION</b>As(2)O(3) induces growth-inhibition and apoptosis of multidrug-resistant K562/ADM cells, and augments synergistically the sensitivity of the cells to conventional chemotherapeutic agents via down-regulation of P-gp expression.</p>