Neutrophil function and cytokine-specific signaling in chronic neutrophilic leukemia.

We diagnosed an 86-year-old woman with chronic neutrophilic leukemia (CNL) because she showed sustained leukocytosis dominated by mature neutrophils, hepatosplenomegaly, high neutrophilic alkaline phosphatase score, absence of the Ph chromosome, low serum level of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF), and no evidence of leukemoid reaction. We found that the extent of stimulation of her neutrophil functions by G-CSF and GM-CSF was greatly reduced compared to healthy donars neutrophils. We showed that CNL neutrophils have intact expression of granulocyte colony-stimulating factor receptor (G-CSFR) and granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR). This suggests that failure of enhancement by G-CSF and GM-CSF in CNL neutrophil functions might be due to disturbances in the intracellular domains of G-CSFR and GM-CSFR, regardless of external cytokine stimulation. However, the patient's neutrophils did not show any mutations in the G-CSFR and GM-CSFR intracellular critical regions. We also showed that stat3 and mitogen-activated protein kinase activation by G-CSF or GM-CSF in the patient's neutrophils were significantly lower than those in healthy donor neutrophils. These results suggest that deficiency of CNL neutrophil function might be due to insufficiency of some inflammatory cytokine-specific signaling. Hence, we are the first to show that CNL neutrophils have partially insufficiency in some cytokine-specific signaling. Further studies are needed to elucidate the signal transduction pathways relating to functional defects in CNL neutrophils.

NFV, an HIV-1 protease inhibitor, induces growth arrest, reduced Akt signalling, apoptosis and docetaxel sensitisation in NSCLC cell lines.

HIV-1 protease inhibitor (PI), nelfinavir (NFV) induced growth arrest and apoptosis of NCI-H460 and -H520, A549, EBC-1 and ABC-1 non-small-cell lung cancer (NSCLC) cells in association with upregulation of p21waf1, p27kip1 and p53, and downregulation of Bcl-2 and matrix metalloproteinase (MMP)-2 proteins. We found that NFV blocked Akt signalling in these cells as measured by Akt kinase assay with glycogen synthase kinase-3alpha/beta (GSK-3alpha/beta) as a substrate. To explore the role of Akt signalling in NFV-mediated growth inhibition of NSCLC cells, we blocked this signal pathway by transfection of Akt small interfering RNA (siRNA) in these cells; transient transfection of Akt siRNA in NCI-H460 cells decreased the level of Bcl-2 protein and slowed their proliferation compared to the nonspecific siRNA-transfected cells. Conversely, forced-expression of Akt partially reversed NFV-mediated growth inhibition of these cells, suggesting that Akt may be a molecular target of NFV in NSCLC cells. Also, we found that inhibition of Akt signalling by NFV enhanced the ability of docetaxel to inhibit the growth of NCI-H460 and -H520 cells, as measured by MTT assay. Importantly, NFV slowed the proliferation and induced apoptosis of NCI-H460 cells present as tumour xenografts in nude mice without adverse systemic effects. Taken together, this family of compounds might be useful for the treatment of individuals with NSCLC.

Intranuclear localization of the transcription coadaptor CBP/p300 and the transcription factor RBP-Jk in relation to EBNA-2 and -5 in B lymphocytes.

We have studied the expression and the localization of the cellular proteins CBP/p300 and RBP-Jk in in vitro EBV-infected human B lymphocytes in relation to the EBNA-2 and EBNA-5 proteins. We found that the level of CBP/p300 was elevated drastically by EBV infection and also after activation by CD40 ligation. Thus the increase in CBP/p300 expression in the EBV-infected cells is related to the virus-induced activation and proliferation of the cells. EBNA-2 and RBP-Jk colocalized in the nucleoplasm, which is in accordance with their functional interaction. We confirmed earlier reports about the presence and colocalization of EBNA-5 and CBP in the nuclear POD bodies. On the other hand, neither EBNA-2 nor p300 was detected in the PODs. The expression of these two proteins overlapped in some distinct dots of the nucleoplasm. Taken together, the different patterns of CBP and p300 expression and their different localization in relation to the PML bodies and two EBV-encoded proteins in the B cells may provide some clue to their distinct functional roles.

Epstein-barr virus can infect B-chronic lymphocytic leukemia cells but it does not orchestrate the cell cycle regulatory proteins.

OBJECTIVES: To understand the mechanism for the refractoriness of B-chronic lymphocytic leukemia (B-CLL) cells for Epstein-Barr virus (EBV)-induced immortalization. STUDY DESIGN/METHODS: Cultures were initiated with EBV-infected tonsillar B and B-CLL cells. Expression of EBNA-2 and some of the key players regulating G1/S phase transition such as c-myc expression, phosphorylation of Rb protein, expression of G1 cyclins, and the cyclin-dependent kinase inhibitor p27 were followed. RESULTS: In line with earlier studies, EBV infection induced c-myc expression, pRb phosphorylation, D2 and D3 expression, and disappearance of p27 in normal B cells. In contrast, EBV-infected B-CLL cells remained resting and they did not express c-myc; cyclin D2, ppRb and cyclin D3 were seen only in occasional cells. Importantly, p27 expression was maintained. CONCLUSIONS: In B-CLL cells, the expression of the EBV-encoded nuclear proteins EBNAs is not followed by entrance to the cell cycle. Thus, the difference in the interaction of EBV-normal B cells and EBV-B-CLL cells is already apparent early after infection.

Human herpesvirus 6 (HHV-6)-positive Burkitt's lymphoma: establishment of a novel cell line infected with HHV-6.

Human herpesvirus 6 (HHV-6) DNA has been detected in several human lymphoproliferative disorders. We report a case of HHV-6-infected Burkitt's lymphoma, from which a cell line, designated Katata, has been established. Katata cells had an immature B-cell phenotype with an L3 morphology and carried a t(8;14)(q24;q32) chromosomal abnormality. The HHV-6 DNA sequences were detected in both the patient's tumor cells and Katata cell line by polymerase chain reaction using three sets of primers that target different regions of HHV-6 DNA. The presence of HHV-6 DNA in Katata cells was also shown by Southern blot hybridization with the BamHI fragment of HHV-6. It is likely that the virus is in a latent state, since (1) virion-associated protein was not expressed in Katata cells, (2) transcriptional level of the immediate-early gene was very low, and (3) no viral particles were observed by electron microscopy. Katata cells were highly tumorigenic in nude mice and the tumor cells also contained HHV-6 DNA. We have successfully obtained several clonal lines by allowing the cells to form colonies in soft agarose and by the limiting dilution method. HHV-6 DNA was detectable in all 13 clones analyzed, suggesting that virtually all Katata cells are infected with HHV-6. This is the first report of a case of HHV-6+ Burkitt's lymphoma in the absence of Epstein-Barr virus. Furthermore, there has been no report of lymphoma cell lines that are persistently and nonproductively infected with HHV-6. The Katata Burkitt's lymphoma cell line, therefore, would provide a useful tool for studies of the mechanisms of HHV-6 latency and reactivation.

High serum levels of CA125 and interleukin-6 in a patient with Ki-1 lymphoma.

We report a 53-year-old-man with an aggressive Ki-1 lymphoma who had high serum CA125, a marker protein of the epithelial ovarian cancer, and interleukin-6 (IL-6) concentrations. Both CA125 and IL-6 levels decreased after chemotherapy and elevated with disease progression. The patient's lymphoma cells obtained before chemotherapy grew continuously in vitro, were IL-6 dependent and were found to secrete CA125 in culture medium. These results indicate that CA125 can be secreted by Ki-1 lymphoma cells and IL-6 may promote the growth of Ki-1 lymphoma cells.