Ya Ping Chen

Glucosylceramide synthase inhibitor PDMP sensitizes chronic myeloid leukemia T315I mutant to Bcr-Abl inhibitor and cooperatively induces glycogen synthase kinase-3-regulated apoptosis

Inactivation of glycogen synthase kinase (GSK)‐3 has been implicated in cancer progression. Previously, we showed an abundance of inactive GSK‐3 in the human chronic myeloid leukemia (CML) cell line. CML is a hematopoietic malignancy caused by an oncogenic Bcr‐Abl tyrosine kinase. In Bcr‐Abl signaling, the role of GSK‐3 is not well defined. Here, we report that enforced expression of constitutively active GSK‐3 reduced proliferation and increased Bcr‐Abl inhibition‐induced apoptosis by nearly 1‐fold. Bcr‐Abl inhibition activated GSK‐3 and GSK‐3‐dependent apoptosis. Inactivation of GSK‐3 by Bcr‐Abl activity is, therefore, confirmed. To reactivate GSK‐3, we used glucosylceramide synthase (GCS) inhibitor PDMP to accumulate endogenous ceramide, a tumor‐suppressor sphingo‐lipid and a potent GSK‐3 activator. We found that either PDMP or silence of GCS increased Bcr‐Abl inhibition‐induced GSK‐3 activation and apoptosis. Furthermore, PDMP sensitized the most clinical problematic drug‐resistant CML T315I mutant to Bcr‐Abl inhibitor GNF‐2‐, imatinib‐, or nilotinib‐induced apoptosis by >5‐fold. Combining PDMP and GNF‐2 eliminated transplanted‐CML‐T315I‐mutants in vivo and dose dependently sensitized primary cells from CML T315I patients to GNF‐2‐induced proliferation inhibition and apoptosis. The synergistic efficacy was Bcr‐Abl restricted and correlated to increased intracellular ceramide levels and acted through GSK‐3‐mediated apoptosis. This study suggests a feasible novel anti‐CML strategy by accumulating endogenous ceramide to reactivate GSK‐3 and abrogate drug resistance.—Huang, W.‐C., Tsai, C.‐C., Chen, C.‐L., Chen, T.‐Y., Chen, Y.‐P., Lin, Y.‐S., Lu, P.‐J., Lin, C.‐M., Wang, S.‐W., Tsao, C.‐W., Wang, C.‐Y., Cheng, Y.‐L., Hsieh, C.‐Y., Tseng, P.‐C., Lin, C.‐F. Glucosylceramide synthase inhibitor PDMP sensitizes chronic myeloid leukemia T315I mutant to Bcr‐Abl inhibitor and cooperatively induces glycogen synthase kinase‐3‐regulated apoptosis. FASEB J. 25, 3661–3673 (2011). www.fasebj.org

Aberrantly expressed AURKC enhances the transformation and tumourigenicity of epithelial cells

Over‐expression of AURKC has been detected in human colorectal cancers, thyroid carcinoma and several cancer cell lines. However, the regulation and clinical implications of over‐expressed AURKC in cancer cells are unclear. Here we show that elevated AURKC increases the proliferation, transformation and migration of cancer cells. Importantly, the kinase activity of AURKC is required for these tumour‐associated properties. Analysis of human cancer specimens shows that the expression of AURKC is increased in cervical cancer, and is highly correlated with staging in colorectal cancer. Over‐expressed AURKC‐GFP localizes to the centromeric regions of mitotic chromosomes and results in a decreased level of AURKB, a key regulator of spindle checkpoint. Expression of AURKC is down‐regulated by PLZF, a transcriptional repressor, through recruitment to its promoter region. The expression levels of PLZF and AURKC mRNA display opposite patterns in human cervical and colorectal cancers. Taken together, our results provide important insights into human cancers with AURKC expression, which may serve as a potential target for cancer therapy in the future. Copyright

Large B cell lymphoma presenting initially in bone marrow, liver and spleen: An aggressive entity associated frequently with haemophagocytic syndrome

Yeh Y‐M, Chang K‐C, Chen Y‐P, Kao L‐Y, Tsai H‐P, Ho C‐L, Wang J‐R, Jones D & Chen T‐Yu2028(2010) Histopathology57, 785–795

Low incidence of thromboembolism in relapsed/refractory myeloma patients treated with thalidomide without thromboprophylaxis in Taiwan

Thromboembolism (TE) is a common complication in patients with multiple myeloma (MM). Immunomodulatory agents, e.g., thalidomide, have expanded the therapeutic options for treating myeloma; however, Western countries report a high incidence of thrombosis in thalidomide-treated MM patients who lack thromboprophylaxis. A Korean trial reported low TE incidence in thalidomide-treated myeloma patients (39xa0% were given aspirin prophylactically). We aimed to elucidate the TE frequency in MM patients in Taiwan who were treated with thalidomide without TE prophylaxis. We retrospectively collected the records of MM patients who had used thalidomide from a single institute between 2004 and 2010, combined these records with two other Taiwanese studies, and compared all three with the Korean trial. In the current Taiwanese series, five of 144 patients (3.5xa0%) developed TE as follows: three (2.1xa0%) were venous and two (1.3xa0%) were arterial. Only 6.1xa0% of the patients had undergone TE prophylaxis, which is less than in the Korean trial (38.9xa0%, pu2009<u20090.05). Of the patients in the relapsed/refractory cohort (nu2009=u2009114) who were given thalidomide alone, none (0/52) developed venous TE (VTE); however, two patients (2/35, 5.7xa0%) who were given thalidomide–dexamethasone as a salvage treatment developed VTE. In the thrombosis cohort, four patients (80xa0%) were treated with thalidomide plus dexamethasone. In conclusion, the frequency of thalidomide-related TE in myeloma patients without effective TE prophylaxis was low in Taiwan. In relapsed/refractory myeloma patients, the VTE frequency was slightly lower compared with Western patients irrespective of treatment with thalidomide alone or combined with dexamethasone. Even in low TE incidence areas, thalidomide combined with dexamethasone was more thrombogenic compared with others.

Translational up-regulation of Aurora-A in EGFR-overexpressed cancer.

Abnormal expression of Aurora‐A and epidermal growth factor receptor (EGFR) is observed in different kinds of cancer and associated with poor prognosis in cancer patients. However, the relationship between Aurora‐A and EGFR in tumour development was not clear. In previous reports, we found that EGFR translocates to nucleus to activate Aurora‐A expression after EGF treatment in EGFR‐overexpressed cells. However, we also observed that not all the EGFR‐overexpressed cells have the nuclear EGFR pathway to mediate the Aurora‐A expression. In this study, we demonstrated that EGF signalling increased the Aurora‐A protein expression in EGFR‐overexpressed colorectal cancer cell lines via increasing the translational efficiency. In addition, the overexpression of EGFR was also associated with higher expression of Aurora‐A in clinical colorectal samples. Activation of the PI3K/Akt/mTOR and MEK/ERK pathways mediated the effect of EGF‐induced translational up‐regulation. Besides, only the splicing variants containing exon 2 of Aurora‐A mRNA showed increased interaction with the translational complex to synthesize Aurora‐A protein under EGF stimulus. Besides, the exon 2 containing splicing variants were the major Aurora‐A splicing forms expressed in human colorectal cancers. Taken together, our results propose a novel regulatory mechanism for the abnormal expression of Aurora‐A in EGFR‐overexpressed cancers, and highlight the importance of alternative 5′‐UTR splicing variants in regulating Aurora‐A expression. Furthermore, the specific expression of exon 2 containing splicing variants in cancer tissues may serve as a potential target for cancer therapy in the future.

Dominant expression of survival signals of endoplasmic reticulum stress response in Hodgkin lymphoma

The accumulation of viral proteins in endoplasmic reticulum (ER) may cause ER stress responses and lead to either apoptosis or survival depending on the driving signals. The strong expression of latent membrane protein‐1 (LMP1) in Epstein–Barr virus (EBV)‐positive Hodgkin lymphoma (HL) cells raises the question whether LMP1‐induced ER stress response is associated with the characteristic tumor biology in HL. In this study, we investigated the expression of ER stress signals (glucose‐regulated protein 78 [GRP78], X‐box binding protein 1 [XBP1], activating transcription factor 6 [ATF6], CCAAT enhance‐binding protein homologous protein [CHOP] and phospho‐apoptosis signal‐regulating kinase 1 [pASK1]) on 156 cases of HL. Furthermore, LMP1 transfection on EBV‐negative HL cell lines was used to explore the regulation of ER stress signals by EBV‐LMP1. Interestingly, we demonstrated that the survival signals of ER stress response (GRP78, 62%; XBP1u [unspliced], 55%; XBP1s [spliced], 38%; ATF6, 91%) were dominantly expressed over the ER death signals (CHOP, 10%; pASK1, 7%) in all histological subtypes of HL with a similar level in both EBV‐positive and EBV‐negative cases. However, expression of ER signals did not bear prognostic significance. In vitro, LMP1 transfection increased the expression of GRP78 and XBP1, but attenuated the expression of death signals, CHOP and pASK1. These data indicate that EBV‐LMP1 may play a role in shifting EBV‐infected cells towards the survival pathway in the presence of ER stress in EBV‐positive HL cases. (Cancer Sci 2011; 102: 275–281)

Systemic Mycobacterium kansasii infection mimicking peripheral T-cell lymphoma

Nontuberculous mycobacteria are opportunistic pathogens which predominantly infect the immunocompromised host. The clinical and pathologic diagnosis of mycobacterial infection is generally not difficult. However, it may mimic malignancy on account of the clinical manifestations or the morphology of atypical lymphocytes with epithelioid histiocytes. The latter can be found in some types of lymphomas, especially T‐cell lymphoma. This report describes two immunocompetent patients with systemic Mycobacterium kansasii infection presenting with fever, systemic lymphadenopathy, and osteolytic bone lesions. The microscopic features of these two cases were similar and were characterized by effacement of the nodal architecture by lymphocytic infiltrates and small aggregates of epithelioid histiocytes throughout. These lymphocytes showed mild atypia and expressed predominantly CD3. Bone marrow was also involved in the same process in one case and T‐cell lymphoma with lymphoepithelioid features was the initial impression. However, further studies reported germline arrangements of T‐cell receptor genes, presence of acid‐fast bacilli, and recovery of M. kansasii in culture. At follow‐up, the lymphadenopathy was seen to have disappeared during antimycobacterial treatment. This report describes two infectious cases with small aggregates of epithelioid histiocytes and atypical lymphocytes mimicking peripheral T‐cell lymphoma; and such cases may become more common as the number of immunosuppressed hosts is increasing worldwide. We have reviewed the literature and summarized useful morphologic criteria for differentiation.

The expression and prognostic significance of platelet-derived growth factor receptor alpha in mature T- and natural killer-cell lymphomas.

Platelet-derived growth factor receptor alpha (PDGFRA) is important in numerous malignancies and can serve as a target for therapeutic strategy. We aimed to assess the role of PDGFRA expression in mature T- and natural killer (NK)-cell lymphomas. We used immunohistochemistry to analyze PDGFRA expression in mature T- and NK-cell lymphomas in tissue samples from 50 patients. In positive samples, we then did a mutational analysis of the PDGFRA gene on exons 10, 12, 14, and 18. The relationship between PDGFRA expression and overall survival in mature T- and NK-cell lymphomas was statistically analyzed in the study. We analyzed PDGFRA expression in four subtypes: angioimmunoblastic T-cell lymphoma (3/8, 37.5%); anaplastic large cell lymphoma (5/7, 71.4%); NK/T-cell lymphoma, nasal type (9/12, 75%); and peripheral T-cell lymphoma, unspecified (PTCLu; 7/23, 30.4%). It was lower in PTCLu than in other subtypes (30.4% vs. 63%, pu2009=u20090.022). PDGFRA expression was not related to PDGFRA gene mutation. Overall survival in mature T- and NK-cell lymphomas correlated significantly with disease subtypes and an international prognostic index but not PDGFRA expression. Our study showed that PDGFRA expression was different in mature T- and NK-cell lymphomas. PDGFRA expression in PTCLu was lower in the present study than in previous reports done in Western countries. It suggests that this disease is biologically distinct in different races (30.4% vs. 91–100%).

Infectious dengue vesicles derived from CD61+ cells in acute patient plasma exhibited a diaphanous appearance

The levels of neutralizing antibody to a pathogen are an effective indicator to predict efficacy of a vaccine in trial. And yet not all the trial vaccines are in line with the theory. Using dengue virus (DENV) to investigate the viral morphology affecting the predictive value, we evaluated the viral morphology in acute dengue plasma compared to that of Vero cells derived DENV. The virions in plasma were infectious and heterogeneous in shape with a “sunny-side up egg” appearance, viral RNA was enclosed with CD61+ cell-derived membrane interspersed by the viral envelope protein, defined as dengue vesicles. The unique viral features were also observed from ex vivo infected human bone marrow. Dengue vesicles were less efficiently neutralized by convalescent patient serum, compared to virions produced from Vero cells. Our results exhibit a reason why potencies of protective immunity fail in vivo and significantly impact dengue vaccine and drug development.

Malignant Effusions Correlate With Poorer Prognosis in Patients With Diffuse Large B-Cell Lymphoma

OBJECTIVESnSerous effusions are a common manifestation of diffuse large B-cell lymphoma (DLBCL). However, their prognostic significance is controversial.nnnMETHODSnWe searched for consecutive patients who had DLBCL with effusions from 1999 through 2007. Primary effusion lymphoma was excluded. The presence of tumor cells in effusions (malignant effusions) was determined by cytology supplemented by flow cytometry, cell blocks with special studies, polymerase chain reaction for clonality, or conventional cytogenetics.nnnRESULTSnForty-one (18.4%) patients had effusions, with 24 (58.5%) developing at diagnosis and 17 (41.5%) during tumor course. Nineteen patients (46.0%) had malignant effusions, with six (31.6%) from local extension and 13 (68.4%) through wide dissemination. Interestingly, malignant effusion correlated with a high International Prognostic Index (IPI) score (r = 0.490, P = .002) and high tumor stage (r = 0.342, P = .031) and was a poor prognosticator (P < .001, log-rank test), even worse than stage IV disease (P = .036). In the multivariate analysis, malignant effusion (P = .056) and supportive care (P = .014) retained significance and were more powerful than IPI score and stage.nnnCONCLUSIONSnPatients who have DLBCL with lymphomatous effusions have a poor prognosis and should be treated as having stage IV disease. The analysis of effusions for tumor cells would be a useful addition to the routine workup.