Effects of human bone marrow stromal cell line (HFCL) on the proliferation, differentiation and apoptosis of acute myeloid leukemia cell lines U937, HL-60 and HL-60/VCR.

This study investigated the effects of human bone marrow fibroblastoid stromal cell line (HFCL) on the proliferation, differentiation and chemosensitivity of acute myeloid leukemia cells (AML) in vitro coculture. By setting up coculture system of sensitive U937, HL-60 cell line and multidrug-resistant (MDR) HL-60/VCR cells in direct contact with human bone marrow fibroblastoid stromal cell line HFCL, or separated by transwell, the proliferation of AML cells cocultured with HFCL cells was inhibited, compared with AML cells alone. And NBT positive cells increased slightly. The percentage of G1 phase cells of AML cells cocultured with HFCL cells was higher than that without HFCL cells, and that of S phase cells was lower. The expression of CD11b and CD14 increased. Meanwhile HL-60 and HL-60/VCR cells treated by TPT were observed to have apoptosis characteristic morphological changes. The proportion of G0/G1 HL-60 and HL-60/VCR cells treated with TPT increased and the sub-G1 increased. The percentage of Annexin V-positive cells and apoptotic cells increased with expression of activated Caspase-3 and the reduced expression of Bcl-2. But when they were cocultured with HFCL cells, the percentage of Annexin V-positive cells and apoptotic cells decreased and sub-G1 reduced. After indirect contact with HFCL cells the expression of activated Caspase-3 decreased and the expression of Bcl-2 increased. After direct contact with HFCL cells for 96 h, the expression levels of 582 genes in HL-60 cells were up-regulated, and 1,323 genes were down-regulated at least twofold by Affymetrix GeneChip Human Genome U133 set A. The expression change in some genes, such as HL14, was confirmed by RT-PCR and northern blot. In a word, HFCL cells could inhibit the proliferation, induce the monocytic differentiation of U937, HL-60 and HL-60/VCR cells, and prevent TPT-induced apoptosis in HL-60 and HL-60/VCR cells via modulation of Bcl-2 and active Caspase-3. Many genes might take part in the influence of HFCL cells on AML cells, which may give important insights into the interaction of bone marrow stromal cells and leukemic cells.

An association between parvovirus B19 and Kikuchi-Fujimoto disease.

Although Kikuchi-Fujimoto disease (KFD) has a higher prevalence among Asian countries, it is a well-defined entity throughout the world. However, its etiology and pathogenesis remain undetermined. To study whether B19 infection is associated with idiopathic KFD (iKFD), we examined the presence of the viral genome and proteins in paraffin-embedded tissues of lymph nodes retrospectively from 33 iKFD patients and 16 age- and sex-matched control subjects by nested PCR (nPCR), in situ hybridization (ISH), and immunohistochemistry (IHC). B19 was detected in 87.1, 69.7, and 57.6% of iKFD specimens by nPCR, ISH, and IHC, respectively, whereas the virus was positive in only 56.3, 31.3, and 25.0% of control tissues by the respective methods (nPCR: p = 0.029; ISH: p = 0.011; IHC: p = 0.032). The IHC-ISH double-staining assay demonstrated that B19-infected cells were mainly lymphocytes and a small number of histiocytes. These results showed for the first time a high frequency of localized persistence of B19 in lymph nodes from iKFD patients, suggesting that B19 might play an important role in the pathogenesis of iKFD.

PRDM1 expression via human parvovirus B19 infection plays a role in the pathogenesis of Hashimoto thyroiditis.

Ectopic lymphoid follicle infiltration is a key event in Hashimoto thyroiditis (HT). Positive regulatory domain zinc finger protein 1 (PRDM1), which is induced by antigen stimulation, can regulate all lymphocyte lineages. Several groups independently demonstrated that human parvovirus B19 (PVB19) is closely associated with HT. Hence, we determined whether PRDM1 is expressed in HT thyroid tissue and whether there is any correlation between PRDM1 expression and PVB19 in the pathogenesis of HT. We detected PRDM1 expression in HT (n = 86), normal thyroid tissue (n = 30), and nontoxic nodular goiter (n = 20) samples using immunohistochemistry. We also detected PVB19 protein in HT samples in a double-blind manner and analyzed the correlation between the 2 proteins using immunofluorescence confocal detection and coimmunoprecipitation. Furthermore, we detected changes of the expression levels of PRDM1 and PVB19 in transfected primary thyroid follicular epithelial cells using real-time quantitative polymerase chain reaction. We found that PRDM1 protein is significantly highly expressed in the injured follicular epithelial cells in HT (83/86 cases) than in normal thyroid cells (0/30 cases) or in nontoxic nodular goiter cells (0/20 cases) (P < .001). In HT, the PRDM1 expression pattern was the same as that of PVB19, whereas PRDM1 and PVB19 were coexistent in the involved epithelial cells. Statistical analysis showed a significant correlation between PRDM1 and PVB19 (P < .001). In addition, primary thyroid epithelial cells also showed PRDM1 up-regulation after PVB19 NS1 transfection. Our findings suggest a previously unrecognized role of PRDM1 and PVB19 in the pathogenesis of HT.

Systematically experimental investigation on carcinogenesis or tumorigenicity of VERO cell lines of different karyotypes in nude mice in vivo used for viral vaccine manufacture.

Many cell lines used for vaccine production have a potentially strong tumorigenic character. Some of those routinely used need to be checked at different passage numbers for this characteristic. Using HeLa cell cultures as positive controls, and primary canine kidney cell (CKC) or feline kidney cell (FKC) cultures purified in vitro on passage three as negative controls, the tumorigenicity of VERO cell sublines was tested in 219 nude mice. The master cell stocks (MCS) and working cell banks (WCB) of eight strains of VERO African green monkey kidney cell (AGMKC) line used for canine, feline and mink vaccine preparation were established in China. The hypo-tetra-ploid JA or hyper-diploid KA strain of VERO line was highly tumorigenic. These data showed a variable chromosome karyotype of VERO line, and contraindicated the use of JA or KA strain of VERO line for the preparation of attenuated viral vaccines. JA or KA strain of VERO line could be a substitute for HeLa line as a positive-control malignant tumor (MT) cell model. The non-carcinogenic YB, JC, M and JB strains of VERO line were therefore selected for the preparation of modified live rabies viral vaccine in place of BHK-21. The cell sub-lines are comparatively stable in terms of their heritable characters, and show little significant changes between passages. In summary, we have found that: 1) the tumorigenicity of cell line is different among different-karyotypic cells; 2) it is the genetic characteristics of chromosomes of cell lines that determines their tumorigenicity, but with species-specific carcinogenicity; 3) the chromosome number variation of cell lines has positive relationship with their carcinogenesis; 4) highly variable strains of tumor cell line can be selected quickly and successfully in nude mice by alternate cultivation in vitro and in vivo. Malignant rhabdoid tumor (MRT) was evolved in nude mice inoculated with violently variable HeLa or VERO cells. The importance of assessing the tumorigenicity in cell sublines used for vaccine production is emphasised.

[Retrospective analysis of 1905 patients with skin cancer from two general hospitals in western China from 1981 to 2000].

OBJECTIVE: To investigate the clinical features and changes in the incidence of skin cancer in two hospitals located in western China. METHODS: The patients diagnosed pathologically as skin cancer from 1981 to 2000 were retrospectively collected from the two hospitals. Clinical data of patients with skin cancer were collected and analyzed. RESULTS: (1) Of the 1 905 patients with skin cancer, squamous cell carcinoma accounted for 29.4%(560 patients), basal cell carcinoma 28.0% (534), and cutaneous malignant melanoma(CMM) 16.0% (305). (2) There were 591 patients with skin cancer diagnosed between 1980 and 1990, and 1 314 between 1991 and 2000, and accounted for 0.34% and 0.58% of all biopsy cases, respectively. The number of total biopsy patients increased 1.6% every year during the 20 years. The number of biopsy patients with skin cancer and with CMM increased 3.5% and 3.9% every year,respectively. (3) Of the 305 CMM patients, 63.3% located on the acra. These patients were elder, and have a higher rate of trauma and a higher incidence in the male than that in patients with CMM located on the other sites. (4) Of the 305 CMM patients, 64 (21%) had history of trauma at the primary onset sites, and 47 (15.4%) had history of small congenital nevi at the primary sites. CONCLUSION: There are some differences in the clinical features such as location and age between the skin cancer patients in our study and those in white population. The incidence of skin cancer in the two hospitals had been increasing in the 20 years (between 1981 and 2000). Both trauma and small congenital nevi are important risk factors of CMM.

[Matrine effects on JM cells by inhibiting proliferation and inducing apoptosis].

OBJECTIVE: To study effects of matrine on JM cell strain. METHOD: Morphologic changes were observed under light microscope with Wright-Giemsa staining, fluorescence microscope with Hoechst 33,258 staining and electron microscope. Alteration of cell cycle of different dose treating groups at the fourth day and 0.8 mg.mL-1 treatment group at the first, second, third, fourth day was analyzed by Flow cytometry. DNA ladder was detected with gel electrophoresis. RESULT: From the third day after treatment of matrine, typical apoptosis features of cells were observed under light microscope and electron microscope in all test groups, and the features were more prominent with the time prolonging. At fourth day, flow cytometry analysis showed that there were sub-G1 peaks in all groups. From 0.1, 0.2, 0.4, 0.6 to 0.8 g.L-1 treatment groups, the rate of apoptotic cells to total cells were 3.1%, 2. 5%, 13.3%, 40.4%, 48.6%, respectively, and what in the control group was 1.4%; the rate of S phase cells to total cells was 28.9%, 26.1%, 27.7%, 0.9%, 14.2%, what in the control group was 30.4%; the rate of G1 phase cells to total cells was 63. 2%, 67.5%, 68.1%, 75.2%, 83.6%, what in the control group was 41.8%; From the first, second, third to fourth day, the rate of apoptotic cells to total cells of 0.8 mg.mL-1 treatment group were 3.0%, 3.7%, 9.1%, 48.6%, respectively; the rate of S phase cells to total cells was 28.6%, 17.5%, 19.1%, 14.2%; the rate of G1 phase cells to total cells were 45.5%, 77.3%, 77.2%, 83.6%. Gel electrophoresis displayed "DNA ladder" in 0.4, 0.6, 0.8 g.L-1 groups, while 0.1 and 0.2 g.L-1 groups didn't show such result. CONCLUSION: Matrine can repress DNA synthesis and arrest JM cell strain at G1 phase, sequentially inhibiting the proliferation of the cell. Besides, this alkaloid can induce the apoptosis of JM cells.

Identification of genuine primary pulmonary NK cell lymphoma via clinicopathologic observation and clonality assay.

Extranodal natural killer (NK)/T-cell lymphoma, nasal type, is an uncommon lymphoma associated with the Epstein-Barr virus (EBV). It most commonly involves the nasal cavity and upper respiratory tract. Primary pulmonary NK/T cell lymphoma is extremely rare. If a patient with a NK or T-cell tumor has an unusual reaction to treatment or an unusual prognosis, it is wise to differentiate NK from T-cell tumors. The clinicopathologic characteristics, immunophenotype, EBV in situ hybridization, and T cell receptor (TCR) gene rearrangement of primary pulmonary NK cell lymphoma from a 73-year-old Chinese woman were investigated and the clonal status was determined using female X-chromosomal inactivation mosaicism and polymorphisms at the phosphoglycerate kinase (PGK) gene. The lesion showed the typical histopathologic characteristics and immunohistochemical features of NK/T cell lymphoma. However, the sample was negative for TCR gene rearrangement. A clonality assay demonstrated that the lesion was monoclonal. It is concluded that this is the first recorded case of genuine primary pulmonary NK cell lymphoma. The purpose of the present work is to recommend that pathologists carefully investigate the whole lesion to reduce the likelihood that primary pulmonary NK cell lymphoma will be misdiagnosed as an infectious lesion. In addition, TCR gene rearrangement and clonal analysis, which is based on female X-chromosomal inactivation mosaicism and polymorphisms at PGK and androgen receptor (AR) loci, were found to play important roles in differentiating NK cell lymphoma from T cell lymphoma. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5205300349457729.

[Effects of human cytomegalovirus on the cell cycle of duct epithelial cell cultures of human salivary gland in vitro and relative mechanism].

OBJECTIVE: To investigate the effects of human cytomegalovirus (HCMV) on the cell cycle of duct epithelial cell cultures of human salivary gland (HSG) in vitro and relative mechanism. METHODS: HSG was cultured in vitro. Reverse transcriptase polymerase chain reaction (RT-PCR) and nest-RT-PCR were used respectively to investigate ie1/ie2 transcription in HSG infected by human cytomegalovirus(HCMV). The effects of HCMV on the cell cycle of HSG were studied by flow cytometry in vitro. The expression of cyclin D1 in HSG infected by HCMV was detected by Western blotting. RESULTS: HCMV iel/ie2 transcription could be detected in HSG infected by HCMV. HCMV arrested productively infected cells in G1 stage. And cyclin D1 was down-regulated in HCMV infected HSG. CONCLUSION: HCMV inhibits proliferation of HSG by affecting G1/S check point and down-regulating cyclin D1 in vitro.

Primary extranodal soft-tissue B-cell lymphoma with abundant immunoglobulin inclusions mimicking adult rhabdomyoma: a case report.

INTRODUCTION: Immunoglobulin inclusions are found in B-cell neoplasms as well as in crystal-storing histiocytosis associated with B-cell lymphoproliferative disorders. At times, the deposits may be so profound as to obscure the diagnosis and may even lead to misdiagnosis. We report one case of low-grade extranodal lymphoplasmacytic lymphoma with abundant immunoglobulin inclusions and emphasize the need for immunophenotyping and molecular assay to make the right decision in diagnosis. To the best of our knowledge, this is the first report of extranodal B-cell lymphoma with abundant intracellular immunoglobulin accumulation. CASE PRESENTATION: A 62-year-old Asian man from China presented with a 13-year history of a right shoulder mass with recent ongoing pain. A desmoplastic fibroma located in the posterior muscles of the neck was suggested by magnetic resonance imaging, and extended local excision was performed. A biopsy, however, revealed large, isolated rhabdoid cells in a diffuse pattern with mild atypia and eosinophilic cytoplasm. Clustered lymphoid cells were interspersed among these cells. The diagnosis was initially suggested to be adult rhabdomyoma. The final diagnosis of lymphoma was made after immunohistochemical, ultrastructural and molecular studies. CONCLUSION: We emphasize this histopathologic and immunohistochemical finding because of the potential for confusion with other tumors or disorders, such as adult rhabdomyoma or crystal-storing histiocytosis.

[Effect of curcumin in combination with bortezomib on proliferation and apoptosis of human multiple myeloma cell line H929 and its mechanism].

This study was aimed to investigate the effect of curcumin in combination with bortezomib on the proliferation and apoptosis of human MM cell line H929 in vitro, and to explore its mechanisms. MTT assay was applied to detect the inhibitory effects of curcumin and bortezomib either alone or combined at different concentrations on H929 cells, and flow cytometry was employed to assay the apoptosis rate. In addition, RT-PCR was used to analyze the mRNA expression of gene BCL-2, BAX, cyclin D1. Immunofluorescence technique was performed to study the location changes of NF-κB P65 in different groups. The results showed that both curcumin and bortezomib inhibited the proliferation of MM cell line H929 in dose-dependent manner, and combination of these two drugs displayed synergistical effect. A much higher apoptosis rate was determined by flow cytometry in combinative groups than that in single or control group. And RT-PCR showed, as compared with curcumin or bortezomib group, there was mRNA expression decrease of BCL-2, cyclin D1 but increase of BAX in combined group. The expression of NF-κB P65 in nucleus was downregulated in either the curcumin or bortezomib group, however, distribution of NF-κB P65 in cytoplasm was observed in combined group. It is concluded that the combination of curcumin and bortezomib is much more effective for the inhibiting proliferation and promoting apoptosis of H929 cell line, which may function by inhibiting the transcription of NF-κB and apoptosis-related genes.

[Bortezomib depresses osteoblast apoptosis induced by mouse myeloma cells].

The purpose of this study was to explore the effect of proteasome inhibitor, bortezomib (Bzb), on osteoblast in pathologic status of myeloma bone disease. The myeloma bone disease was modeled by co-culture of mouse myeloma cell RPMI8226 with osteoblast line MC-3T3E1 from mouse calvaria, and intervenient culture of supernatant. The inhibitory effect of Bzb on proliferation of MC-3T3E1 assayed by modified MTT method, the apoptosis of MC-3T3E1 cells was determined by flow cytometry with Annexin V/PI staining, the expressions of osteoblast markers, Runx2/cbfa1, osteocalcin (OCN) and osterix (OSX) in MC-3T3E1 treated with Bzb were detected by RT-PCR and Western blot respectively. Experiments were divided into 3 group: single cultured, co-cultured and supernatant-interveniently cultured groups. The results showed the Bzb in higher concentration inhibited proliferation of MC-3T3E1 cells in a dose-dependent manner, with the IC(50) of 38.1 nmol/L for 48 hours, the Bzb in low concentration (5 nmol/L) did not show the inhibitory effect on proliferation of MC-3T3E1 in single cultured group (p>0.10), but could decrease apoptotic rate of MC-3T3E1 by 32.5% and 24.6% respectively in cocultured and supernatant-interveniently cultured groups, moreover increased the expression of osteoblast-related gene OSX, OCN mRNA and protein (p<0.05), while no obvious change of Runx2/cbfa1 expression was observed (p>0.05). It is concluded that the proteasome inhibitor, Bzb, in low concentration promotes the activity of osteoblast internal mechanisms, and prevents the apoptosis of osteoblasts induced by myeloma cells. In addition, it can up-regulate transcription and expression of osteoblast markers related to Runx2/cbfa1 path way, thus may protect osteoblasts in myeloma bone disease.

[Bcl-6 expression in K562 cells and its role in mechanism underlying induced differentiation into various myelocytic lineages].

This study was purposed to investigate the changes of bcl-6 expression in K562 cells and the mechanism inducing differentiation into different myelocyte lineages. Models of K562 cells inducing differentiation to lineages of megakaryocyte, erythrocyte and macrophagocyte were established with inducers TPA (tetradecanoylphorbol 13-acetate), Hu (hydroxyurea) and HMBA (hexamethylene bisacetamide) respectively. Western blot assay was applied to detect the expression of bcl-6 in K562 cells before and after the induction. Meanwhile, PCR, cloning and direct DNA sequencing were used to identify mutations in the 5' regulatory region of bcl-6 in K562 cells before and after induction with TPA. The results indicated that up-regulation of bcl-6 expression was found only in K562 cells being induced differentiating into megakaryocyte-lineage, while mutation of 5' regulatory region of bcl-6 gene was not found. It is concluded that expression of bcl-6 increases only when K562 cells differentiate into megakaryocyte lineage and bcl-6 expression may play an important role in K562 cells induced differentiation into megakaryocyte lineage. The up-regulation of bcl-6 expression may not be related with the mutation of 5' regulatory regions of the gene.

[Changes and mechanism of apoptosis-related gene expression in T lymphocytic leukemia JM cells induced with matrine].

This study was purposed to investigate the changes of apoptosis-related gene expression in T lymphocytic leukemia JM cells induced with matrine, and its possible mechanism. JM cells was induced with 0.4 mg/ml matrine for 4 days, the total RNA was extracted from JM cells before and after matrine induction, the differential expression of apoptosis-related genes were screened with cDNA Expression Array Kit, the expression change of a part of gene was checked by Western blot. The results indicated that after induction of JM cells with matrine, differential expression of 31 genes were found by gene chip hybridization, the expression of caspase 8 was up-regulated more than 5 times. Western blot analysis showed that the up-regulation of caspase 8 gene expression positively correlated with induction time. It is concluded that differential expressions of many apoptosis-related genes in JM cells can be induced by matrine, in which gene expression of caspase 8 is up-regulated notably.

[Apoptosis of multiple myeloma cells induced by gossypol acetic acid in vitro and its mechanism].

This study was aimed to investigate the apoptosis effect of gossypol acetic acid on classic human multiple myeloma RPMI8226 cell line in vitro and its mechanism. The inhibitory effect on proliferation of RPMI8226 cells was evaluated by means of MTT assay. Cytotoxic effect and apoptosis was identified and analyzed with the aid of transmission electron microscopy, mitochondria membrane potential (MMP) and DNA gel electrophoresis. Meanwhile, Western-blot assay was used to detect the changes of several key cell apoptosis regulatory proteins such as BAX, caspase-3 and caspase-8 in these cells before and after treatment. The results showed that low concentrations of gossypol acetic acid (> 16 micromol/L) could suppress the proliferation and induce the apoptosis in RPMI8226 cells effectively. At the same time, gossypol acetic acid could also down-regulate the mitochondrial membrane potential, up-regulate the expression of the apoptosis-related protein such as BAX and caspase-3. It is concluded that the gossypol acetic acid can selectively induce proliferation inhibition and apoptosis of multiple myeloma RPMI8226 cells with a smaller dose.

Overexpression of CYP2E1 enhances sensitivity of hepG2 cells to fas-mediated cytotoxicity.

Hepatocellular carcinoma (HCC) has been reported to be resistant to Fas-mediated apoptosis. In present study, experiments were conducted to investigate the potential effects of CYP2E1 overexpression on susceptibility of HCC to Fas-mediated cytotoxicity. HCC cell line HepG2 was infected with Ad-CYP2E1 to enhance the expression of CYP2E1, followed by treatment with low toxic dose of recombinant human Fas ligand (FasL, 0.5 ng/ml) in the presence of Actinomycin D (Act D, 125 ng/ml). High level of Fas expression was found in HepG2 cells. Its protein level and distribution kept unchanged after different treatments. Compared with control, CYP2E1 expressed HepG2 cells were more sensitive to FasL plus Act D. The sensitivity was elevated in a multiplicity of infection (m.o.i)-dependent manner, which was dramatically suppressed by CYP2E1 inhibitor diallyl disulfide (DAS) (p < 0.01). The percentage of apoptotic cells caused by FasL/Act D was increased from 18.7 to 75% after infection with Ad-CYP2E1 (p < 0.01). DAS treatment resulted in 60% reduction of apoptotic ratio (p < 0.01). Antioxidants GSH ethyl ester, Vitamin C and Vitamin E efficiently protected against cytotoxicity induced by FasL plus Act D in CYP2E1-expressed HepG2 cells. After adding FasL/Act D, increased caspases activities, lipid preoxidation and reduced GSH level, as well as mitochondrial release of cytochrome c were found in Ad-CYP2E1 infected cells (all p < 0.01); these changes were significantly attenuated by DAS (all p < 0.05). These results suggested that CYP2E1 potentiates Fas-mediated HepG2 cells toxicity via the induction of oxidative stress to promote apoptosis. Adenovirus-mediated overexpresson of CYP2E1 may have an important role in the elimination of hepatoma cells mediated by immune effector cells in the liver.

[Differentiation of HL-60 cells directly cocultured with HFCL cells and alteration of their gene expression profile].

To study the molecular mechanism of the effect of fibroblastoid stromal cells (HFCL) from human bone marrow on the proliferation and differentiation in acute myeloid leukemia HL-60 cells, the cell cycle was analyzed by flow cytometry (FCM); the cell differentiation was determined by morphology NBT test and flow cytometric detection for expression of CD11b, CD14, CD13 and CD33; the genes differently expressed between HL-60 cells and HL-60 cells directly cocultured with HFCL were detected by using Affymetric oligo microarray technique. The changes of expression in some key genes were confirmed by using RT-PCR and Northern blot. The results showed that the percentage of G(1) phase cells in AML cells cocultured with HFCL cells was higher than that without HFCL cells, and the percentage of S phase cells was lower. The NBT positive cells and the expression of CD11b and CD14 increased. It was found that after direct contact of HL-60 cells with HFCL cells for 96 hours, the expression levels of 582 genes were up-regulated, 1 323 genes down-regulated. It is concluded that many genes may take part in the influence of HFCL cells on HL-60 cells, which may give important insights into the important molecules and pathways or cross-talk involved in the interaction between the AML cells and stromal cells.

Bcl2-negative follicular lymphomas frequently have Bcl6 translocation and/or Bcl6 or p53 expression.

Bcl2 is an important protein involved in the pathogenesis of follicular lymphoma (FL). However, approximately 10% of FL cases do not express Bcl2. The present study was designed to compare gene aberrations, prosurvival gene expression, apoptosis and proliferation rates in Bcl2-positive and -negative FL cases. Bcl2 translocation and Bcl6 translocation were detected and compared using fluorescence in situ hybridization (FISH). A tendency for Bcl6 translocation to occur was found more frequently in Bcl2-negative FL than in the Bcl2-positive cases. The expression of Bcl-X, BAX, p53, Bcl6 was analyzed by immunohistochemistry. Bcl2 family proteins Bcl-X and BAX were expressed similarly in the two FL types. In some cases of Bcl2-negative FL there was high expression of Bcl6 or p53 but no such Bcl2-positive FL cases were detected. Furthermore, there was an inverse relationship between the expression of Bcl6 and p53. These results indicate that the Bcl6 translocation occurs more frequently in Bcl2-negative FL. Furthermore, other prosurvival proteins such as p53 and Bcl6 may play an important role in the pathogenesis of Bcl2-negative FL.

[Difference of gene expression profiles between HL-60/VCR and HL-60 cells detected by human genome genechip].

This study was aimed to detect the gene expression profile changes between human acute leukemia cell line HL-60 and VCR-resistance HL-60, and to investigate the underlying mechanisms of MDR by using genechip technology. In experiments, mRNA were harvested using TrizoL reagent from these two cell lines, through RT-PCR, the biotinylated nucleotide were incorporated into the cRNA during the in vitro transcription reaction. The high quality RNA was hybridized to the gene expression array--human genome U133A developed by Affymetrix. It was scanned by G2500A GeneArray Scanner and the acquired image was analysed by a series of softwares. The results showed that 5,507 genes were differentially expressed between human acute leukemia cell line HL-60 and VCR-resistant HL-60. Compared with HL-60, 3,100 genes were up-regulated and 2,407 genes were down-regulated in VCR-resistant cell line. These genes were involved in different cell activities such as growth regulation and signal transduction. Among the genes with remarkable differential expression between the two cell lines, 435 were up-regulated and 605 were down-regulated. It is concluded that many different kinds of genes are involved in the mechanism of MDR and there is an intricate molecular network that controls the sensitivity of leukemia cells to the chemotherapeutic agents. Genechip is an efficient tool for parallel gene expression analysis.

Glucosamine sulfate-induced apoptosis in chronic myelogenous leukemia K562 cells is associated with translocation of cathepsin D and downregulation of Bcl-xL.

Cathepsin D (cat D) reportedly plays an important role in certain apoptotic processes, the downstream pathways of which involve release of cytochrome c (cyt c) from mitochondria and activation of the caspase cascade. Previous studies revealed that the B-cell lymphoma 2 (Bcl-2) family members Bax or Bid play important roles in apoptotic signal transduction between cat D and mitochondria. Here, we show that glucosamine sulfate (GS) inhibits the proliferation and induces apoptosis of human chronic myelogenous leukemia K562 cells in vitro. GS interfered with the maturation of cat D. Activation of caspase-3, cleavage of poly-(ADP-ribose)-polymerase, release of cyt c, and downregulation of Bcl-xL accompanied GS-induced apoptosis, and these processes were inhibited by the cat D inhibitor pepstatin A. However, we did not detect any altered gene expression of Bcl-2, Bax, or Bid during apoptosis. Translocation of cat D from the lysosome to the cytosol was observed in GS-treated K562 cells. These findings suggest that GS-induced K562 cell apoptosis involves the translocation of cat D from the lysosome to the cytosol. Furthermore, our findings suggest that downregulation of Bcl-xL (but not Bcl-2, Bax, or Bid) connects cat D and the mitochondrial pathway, which causes the release of cyt c and activation of the caspase cascade during GS-induced apoptosis of K562 cells.