Engagement of CD99 Reduces AP-1 Activity by Inducing BATF in the Human Multiple Myeloma Cell Line RPMI8226.

CD99 signaling is crucial to a diverse range of biological functions including survival and proliferation. CD99 engagement is reported to augment activator protein-1 (AP-1) activity through mitogen-activated protein (MAP) kinase pathways in a T-lymphoblastic lymphoma cell line Jurkat and in breast cancer cell lines. In this study, we report that CD99 differentially regulated AP-1 activity in the human myeloma cell line RPMI8226. CD99 was highly expressed and the CD99 engagement led to activation of the MAP kinases, but suppressed AP-1 activity by inducing the expression of basic leucine zipper transcription factor, ATF-like (BATF), a negative regulator of AP-1 in RPMI8226 cells. By contrast, engagement of CD99 enhanced AP-1 activity and did not change the BATF expression in Jurkat cells. CD99 engagement reduced the proliferation of RPMI8226 cells and expression of cyclin 1 and 3. Overall, these results suggest novel CD99 functions in RPMI8226 cells.

Autophagic Markers BECLIN 1 and LC3 are Associated with Prognosis of Multiple Myeloma.

BACKGROUND/AIMS: Autophagy is crucial for the survival and function of plasma cells including protection from toxic misfolded immunoglobulin and proper energy metabolism. Multiple myeloma (MM) is an indolent but eventually fatal neoplasm of plasma cells. Autophagy may play a critical role in the survival of MM cells and their response to chemotherapeutic agents. In this study, we correlated the expression of autophagy-related proteins with the prognosis of MM. METHODS: In this retrospective cohort study, we examined the expression of the autophagic markers BECLIN 1 and microtubule-associated protein light chain 3 (LC3) in 89 cases of MM biopsied from 2001 to 2004 at the Asan Medical Center. The association of the expression scores of these markers with clinical outcomes was assessed. RESULTS: Patients with strong immunoreactivity to BECLIN 1 or LC3 had a significantly better overall survival (OS) than patients with negative to moderate immunoreactivity (p = 0.036 and 0.018, respectively). This was also true for disease-specific survival (DSS; p = 0.051 and 0.043, respectively). In addition, LC3 immunostaining remained an independent factor impacting OS (p = 0.028) and DSS (p = 0.020) after multivariate analysis. CONCLUSIONS: The results of this study suggest that higher immunoreactivity for autophagic markers in MM is associated with superior patient survival.

Expression of CD99 in Multiple Myeloma: A Clinicopathologic and Immunohistochemical Study of 170 Cases.

BACKGROUND: Multiple myeloma (MM) is a heterogeneous and ultimately fatal disease. Risk stratification using prognostic biomarkers is crucial to individualize treatments. We sought to investigate the role of CD99, a transmembrane protein highly expressed in many hematopoietic cells including subpopulations of normal and neoplastic plasma cells, for MM risk stratification. METHODS: CD99 expression was measured in paraffin samples of bone marrow and extramedullary biopsies of 170 patients with MM. Patients were divided into those with high score (moderately and strongly positive) and low score (negative and weakly positive), with all staining being cytoplasmic and/or membranous. RESULTS: High anti-CD99 immunostaining was observed in 72 of 136 (52.9%) bone marrow biopsies and 24 of 87 (27.6%) extramedullary biopsies in MM. High CD99 expression of extramedullary specimens was associated with significantly longer overall survival (OS; p=.016). High CD99 expression of extramedullary specimens was also associated with better prognosis in the nonautologous stem cell transplantation group of MM patients (p=.044). In multivariate analysis, International Staging System stage was an independent prognostic factor, whereas CD99 expression was no longer statistically significant. CONCLUSIONS: Expression of CD99 in extramedullary specimens was correlated with longer OS, suggesting that CD99 may be a helpful immunohistochemical marker for risk stratification.

Differential expression patterns of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) -1, -4, -5, and -14 in human placenta and gestational trophoblastic diseases.

CONTEXT: The ability of intermediate trophoblasts to invade maternal tissue during placentation depends on how well they can degrade the extracellular matrix. Invasion into the extracellular matrix requires many complex proteases. A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) is a novel family of secreted metalloproteinases. The ADAMTS-1, -4, -5, and -14 subtypes are known to be expressed in human placenta, but little is understood about their expression patterns. OBJECTIVE: To examine the expression patterns of ADAMTS-1, -4, -5, and -14 in specific human placenta cell types during gestation and in gestational trophoblastic diseases. DESIGN: Placental tissues were obtained from 25 pregnant women and 21 cases of gestational trophoblastic diseases (10 early complete moles, 3 placental site trophoblastic tumors, 4 invasive moles, and 4 choriocarcinomas). The expression of the 4 ADAMTS was analyzed by immunohistochemistry. RESULTS: ADAMTS-1, -4, -5, and -14 were differentially expressed by the human placenta throughout gestation in a time-specific and cell type-specific manner, as well as in gestational trophoblastic diseases. ADAMTS-1 showed gradually strong staining intensity in gestational trophoblastic diseases according to the invasive potential but showed consistent strong intensity throughout normal placenta. ADAMTS-4 and ADAMTS-5 exhibited higher and restricted expression in first-trimester intermediate trophoblasts. They also exhibited comparably strong expression in gestational trophoblastic diseases. However, ADAMTS-14 expression remained unchanged throughout gestation. CONCLUSIONS: The restricted expression pattern of ADAMTS-4 and ADAMTS-5 and their increased expression in gestational trophoblastic diseases suggest that these 2 ADAMTS subtypes are associated with a biological phenotype of trophoblasts involved in human placentation and the development of gestational trophoblastic diseases.

Differences in intravascular ultrasound and histological findings in culprit coronary plaques between ST-segment elevation myocardial infarction and stable angina.

A comprehensive evaluation of culprit coronary lesions may help to understand vulnerable plaques responsible for ST-segment elevation myocardial infarction (STEMI). We compared intravascular ultrasound (IVUS) and histological findings in culprit coronary plaques from 94 patients with STEMI (n = 54) or stable angina (n = 40). Tissue specimens were obtained by directional coronary atherectomy and IVUS was performed before percutaneous coronary intervention. IVUS and histological data were analyzed. Clinical characteristics were largely similar between the two groups. Plaque rupture and thrombi were more frequently found in the STEMI group than in the stable angina group. There were no significant differences between plaque types or proximal and distal reference measurements in the two groups. However, the site of minimal lumen area had a greater vessel area, remodeling index, and plaque burden with lesser lumen area in the STEMI group than in the stable angina group. Plaque areas immunopositive for CD68 and CD31 were significantly larger in the STEMI group, while the area immunopositive for α-smooth muscle actin was larger in the stable angina group. In conclusion, culprit lesions in STEMI patients showed a greater plaque burden, remodeling index, and more frequent thrombi with increased inflammation and neovascularization compared to the stable angina group, supporting the current concept of vulnerable plaques being responsible for STEMI.

Expression of stanniocalcin-1 in culprit coronary plaques of patients with acute myocardial infarction or stable angina.

BACKGROUND: Stanniocalcin-1 (STC1) is involved in fundamental biological processes such as angiogenesis, inflammation and wound healing, but little is known about its expression in human coronary atherosclerotic plaques or its relationship to plaque instability. OBJECTIVE: STC1 expression was examined in the culprit coronary plaques of 70 patients with acute myocardial infarction (AMI; n=49) or stable angina (n=21) who underwent directional coronary atherectomy. METHODS: The specimens were stained with H&E, STC1-specific antibodies, and endothelial cells, macrophages and smooth muscle cell markers. RESULTS: The baseline characteristics of the two groups of patients were largely similar. CD31-immunopositive and CD68-immunopositive areas, indicative of the presence of endothelial cells and macrophages, respectively, were proportionately larger while areas immunopositive for α-actin, as a smooth muscle cell marker, were proportionately smaller in the AMI group than in the stable angina group. The proportion of STC1-immunopositive areas was significantly greater in the AMI group than in the stable angina group (20.0% (8.2-29.0%) vs 8.8% (3.9-19.4%), p=0.022). Areas positive for STC1 were independently correlated with those immunopositive for CD31 (r=0.42, p<0.001) and CD68 (r=0.40, p<0.001). STC1 immunoreactivity co-localised with CD31-immunopositive and CD68-immunopositive cells. CONCLUSIONS: STC1 is differentially expressed in the culprit coronary plaques of patients with AMI versus those with stable angina. STC1 may play a role in plaque instability.

Sensitive detection of EML4-ALK fusion oncoprotein of lung cancer by in situ proximity ligation assay.

BACKGROUND: EML4-ALK fusion oncogene has emerged as a novel molecular target in non-small cell lung cancer (NSCLC). Although break-apart fluorescent in situ hybridization (FISH) is the standard method for diagnosis, it is expensive, not readily available and sometimes difficult to interpret. In addition, ALK immunohistochemistry (IHC) may miss the diagnosis because of relatively low level of ALK transcription. METHODS: In situ proximity ligation assay (PLA) originally developed for precise detection and quantification of proteins by dual recognition and amplification process was used for sensitive detection of EML4-ALK fusion oncoprotein in NSCLC cell lines (ALK negative cell: PC-9 and H460, ALK positive cell: H3122 and H2228). EML4-ALK oncogene and protein in lung cancer cells were confirmed by multiplex RT-PCR and Western blots. RESULTS: We detected 117 kDa variant 1 of EML4-ALK in H3122 and 90 kDa variant 3 of EML4-ALK in H2228. These cells were more sensitive to crizotinib, an ALK inhibitor compared with PC-9 and H460 cells without EML4-ALK rearrangement. After fixing on glass slides by cytospin centrifuge, in situ PLA test was performed. Among four cell lines, distinct, tiny spots were visible only in H3122 and H2228 cell lines with ALK rearrangement. The same results were also obtained when paraffin-embedded cell blocks were used. CONCLUSIONS: Highly specific and sensitive detection of EML4-ALK fusion oncoprotein is possible by in situ PLA method suggesting its clinical application.

Comparison of intravascular ultrasound and histological findings in culprit coronary plaques between ST-segment elevation and non-ST-segment elevation myocardial infarction.

It remains uncertain whether the histology of culprit coronary plaques differs between ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). We compared intravascular ultrasound (IVUS) and histologic findings in coronary culprit plaques among patients presenting with STEMI and NSTEMI. Atherectomy specimens were obtained from 96 patients, 70 with STEMI and 26 with NSTEMI, who underwent directional coronary atherectomy for de novo coronary artery lesions. IVUS examinations were performed before directional coronary atherectomy. IVUS and histologic data were analyzed. Clinical characteristics were largely similar between the 2 groups; however, normal antegrade flow before angioplasty was less frequently observed in patients with STEMI than those with NSTEMI. Plaque rupture was more common on the proximal side of the minimal lumen site. There were no differences in vessel area, lumen area, calcification, plaque burden, or remodelling index at the reference and culprit sites. However, the arc of the ruptured cavity was significantly greater in patients with STEMI than those with NSTEMI (69.4 ± 27.9° vs 51.8 ± 20.0°, respectively, p = 0.008). The proportion of atheroma, fibrocellular, and thrombus areas was not different between the 2 groups. Similarly, the relative areas immunopositive for CD31, smooth muscle α-actin, and CD68 were similar in the 2 groups. In conclusion, coronary culprit lesions in patients with STEMI show more severe plaque rupture with similar histologic features than those in patients with NSTEMI, supporting the idea that a large plaque rupture is more likely in STEMI patients.

Macrophage heterogeneity of culprit coronary plaques in patients with acute myocardial infarction or stable angina.

We investigated the polarization states of macrophages in coronary atherectomy tissues retrieved from patients with acute myocardial infarction (AMI, n = 52) or stable angina pectoris (SAP, n = 22). The specimens were analyzed immunohistochemically using antibodies specific to CD11c (M1 marker), CD206 (M2 marker), and to markers of endothelial cells, macrophages, and smooth muscle cells. Baseline characteristics were similar in the 2 groups. The proportion of areas immunopositive for α smooth muscle actin was similar, but those positive for CD31 and CD68 were larger in the AMI group compared with the SAP group. In addition, AMI had significantly greater areas immunopositive for CD11c (P = .007) than did SAP, but CD206 (P = .102) positivity was not different in the 2 groups. In conclusion, M1 macrophage infiltration, not M2 macrophage infiltration, was increased in culprit plaques of patients with AMI. Macrophage heterogeneity may therefore be related to plaque instability.

An effective immune-monitoring protocol based on gene expression profiles in the peripheral T-cell fraction reactive to graft antigens.

BACKGROUND: The ability to induce tolerance, or at least minimize the need for immunosuppressive therapy, is a high priority in organ transplantation. Accomplishing this goal requires a novel method for determining when a patient has become tolerant to or is rejecting their graft. Here, we sought to develop an efficient monitoring protocol based on gene expression profiles of recipient T cells in murine skin and islet allograft models. METHODS: Unlike previous studies, here, gene expression analysis was focused on donor antigen-reactive T cells, which were prepared by collecting CD69(+) T cells from cocultures of recipient peripheral T cells and donor antigen-presenting cells. Candidate tolerance and rejection biomarker genes were selected from a CD69(+) T-cell microarray analysis, and their expression levels were measured in the recipient CD69(+) T-cell fraction using quantitative reverse transcription polymerase chain reaction. RESULTS: Our new monitoring protocol was capable of precisely detecting the immune status of recipients relative to their graft regardless of the organ received, whether they were taking immunosuppressive drugs, or different strains of origin. CONCLUSIONS: Gene expression analysis focusing on recipient CD69(+) T cells as the donor antigen-reactive T-cell population could be used as an effective and sensitive method for monitoring transplant patients.

Innate immunity markers in culprit plaques of acute myocardial infarction or stable angina.

We analyzed the innate immunity markers, C-reactive protein (CRP), serum amyloid P component (SAP) and pentraxin-3 (PTX-3), and metalloproteinase-9 (MMP-9) in coronary atherectomy tissues obtained from patients with acute ST elevation myocardial infarction (STEMI) (n=27) or stable angina (n=15). The relative areas immunopositive for CRP and SAP were similar in the two groups. In contrast, the proportion of areas immunopositive for PTX-3 and MMP-9 was higher in the STEMI group, compared to the stable angina group. PTX-3 or MMP-9-stained areas largely overlapped with those positive for CD68. We concluded that PTX-3 plays a role in the pathogenesis of STEMI.

Expression of ADAMTS-2, -3, -13, and -14 in culprit coronary lesions in patients with acute myocardial infarction or stable angina.

ADAMTS (a disintegrin and metalloproteinase with thrombospondin type 1 motifs) proteases are emerging as key participants in the pathogenesis of vascular diseases. We studied the expression of ADAMTS-2, -3, -4 and -14 in the culprit plaques from patients presenting with acute myocardial infarction (AMI) versus stable angina. Tissue samples were gathered from 52 patients with AMI (n = 35) or stable angina (n = 17) who underwent directional coronary atherectomy. The specimens were stained with hematoxylin-eosin and analyzed immunohistochemically using antibodies specific to ADAMTS-2, -3, -13 and -14, and markers for endothelial cells, macrophages, and smooth muscle cells. Baseline characteristics of the groups were mostly similar. The proportion of smooth muscle α-actin-immunopositive area was smaller in the AMI group than in the stable angina group, but the areas immunopositive for CD31 or CD68 were higher in the AMI group. The relative areas immunopositive for ADAMTS-2, -3, and -13 in AMI were significantly larger than those in stable angina. However, the proportion of areas immunopositive for ADAMTS-14 did not differ between the two groups. Areas that stained for ADAMTS-2, -3, -13, and -14 largely overlapped with those positive for CD31 or CD68. The areas immunopositive for ADAMTS proteases were significantly correlated with CD31- or CD68-immunostained areas. In conclusions, ADAMTS-2, -3, and -13 expression, but not that of ADAMTS-14, are increased in plaques causing AMI compared those associated with stable angina. These results support a role for these enzymes in the pathogenesis of AMI.

Expression of JL1 in Burkitt lymphoma is associated with improved overall survival.

JL1 is a novel molecule expressed in the surface of hematopoietic precursor cells, but not on any other mature human tissue. Accordingly, JL1 is expressed in acute lymphoblastic leukemia (ALL) cells and can be used both for specific diagnosis and as a target for treatment. However, expression of JL1 by lymphomas has not been thoroughly assessed. Burkitt lymphoma is a potentially curable aggressive lymphoma, but prognostic markers that stratify risk have not been established. We therefore assayed JL1 expression in Burkitt lymphoma patients to assess its value as a prognostic marker for this disease. Tissue microarray blocks of formalin-fixed paraffin-embedded tissue samples from patients with Burkitt lymphoma and other B-cell lymphomas, at the Asan Medical Center and Seoul National University Hospital from January 1998 to December 2008 were immunohistochemically assayed using a mouse monoclonal antibody against JL1. We found that 30.2% of Burkitt lymphoma samples, but no other lymphoma samples, were positive for JL1. JL-1 expression was significantly correlated with patient survival (P = 0.022), but not with other clinical manifestations of the disease, with 91.6% of JL1-positive patients achieving complete remission in response to chemotherapy and 6.25% experiencing disease recurrence. JL1 positivity was significantly correlated with prolonged overall survival by both Kaplan-Meier survival (P = 0.035) and Cox proportional hazard model (P = 0.043) analysis. JL1 expression in Burkitt lymphoma was positively correlated with overall survival and better response to chemotherapy, suggesting that JL1 may be a prognostic marker for risk stratification in these patients.

Comparison of differential expression of P2Y12 receptor in culprit coronary plaques in patients with acute myocardial infarction versus stable angina pectoris.

P2Y12 receptor antagonists may have pleiotropic benefits. Little is known, however, about the expression of P2Y12 receptors in coronary atherosclerotic plaques. We investigated the expression of P2Y12 receptor in coronary atherectomy tissues retrieved from patients with acute myocardial infarction (AMI) or stable angina pectoris (SAP). Tissue specimens were collected from 35 patients with AMI and 19 with SAP who underwent directional coronary atherectomy. Specimens were analyzed immunohistochemically using antibodies specific to P2Y12 receptor and to markers of endothelial cells, macrophages, and smooth muscle cells. The 2 groups had similar baseline clinical characteristics. Plaque types were more likely to be cellular in the AMI group. The proportion of areas immunopositive for α-smooth muscle actin was smaller but those positive for CD31 and CD68 were larger in the AMI than in the SAP group. In addition, the relative area immunopositive for P2Y12 receptor was significantly larger for AMI than SAP (1.1 ± 0.9% vs 0.5 ± 0.4%, respectively, p < 0.001). P2Y12 receptor positivity coincided with areas positive for CD31 and α-smooth muscle actin. In conclusion, P2Y12 receptor is present in coronary atherosclerotic plaques and is increased in culprit plaques of patients with AMI. P2Y12 receptor may play a role in plaque destabilization.

Comparison of ruptured coronary plaques in patients with unstable and stable clinical presentation.

It remains uncertain why some plaque ruptures trigger acute coronary syndrome (ACS), whereas others do not. We investigated the anatomic features and tissue factor (TF) expression at the sites of plaque rupture in 42 patients presenting with ACS (n = 23) or stable angina (n = 19). Intravascular ultrasound examination was performed before directional coronary atherectomy. Specimens were stained with antibodies against TF, CD68 positive phagocytic cells, and smooth muscle cells; and intravascular ultrasound and immunohistochemistry results were compared. Baseline demographic and clinical characteristics, as well as vessel and lumen sizes at both reference and lesion sites, were comparable in the two groups. However, the remodeling index and plaque burden at lesion sites were significantly greater in the ACS than in the stable angina group. The TF-immunopositive areas were significantly greater in the ACS than in the stable angina group (0.07%; IQR [0.02-0.16%] vs. 0.02%; IQR [0.01-0.05%], P = 0.022), whereas the proportions of CD68-positive and smooth muscle cell areas were similar. There was a significant correlation between areas positive for TF and those positive for CD68 (r = 0.83, P < 0.001). In conclusion, ruptured plaques in patients with ACS show stronger TF expression, a greater plaque burden, and a higher remodeling index than do plaques in those with stable angina, suggesting that both lesion morphology and local thrombogenicity are related to clinical symptoms after plaque rupture.

Comparison of ADAMTS-1, -4 and -5 expression in culprit plaques between acute myocardial infarction and stable angina.

BACKGROUND: ADAMTS (a disintegrin and metalloproteinase with thrombospondin type 1 motifs) proteases might contribute to plaque destabilisation by weakening the fibrous cap. However, little is known about the expression of ADAMTS proteases in coronary atherosclerotic plaques. OBJECTIVE: To examine the expression of ADAMTS proteases in coronary atherectomy samples obtained from patients with acute myocardial infarction (AMI) or stable angina. METHODS: Atherectomy specimens were obtained from 34 patients with AMI (n=23) or stable angina (n=11) who underwent directional coronary atherectomy. The specimens were stained with H&E and analysed immunohistochemically using antibodies specific to ADAMTS-1, -4 and -5; versican cleavage products; and markers for endothelial cells, macrophages and smooth muscle cells. RESULTS: Baseline characteristics were similar between the two groups. The proportion of CD31 and CD68 immunopositive areas did not differ between the two groups, but the area immunopositive for smooth muscle α-actin was smaller in the AMI group. The relative area immunopositive for ADAMTS-1 in AMI (1.04% (IQR 0.59-2.09%)) was significantly greater than that in stable angina (0.24% (0.15-0.39%); p<0.001). In contrast, the proportion of areas immunopositive for ADAMTS-4 or -5 was similar in the two groups. Areas that stained for ADAMTS-1 largely overlapped with those positive for CD68 and versican cleavage products. The areas immunopositive for ADAMTS-1 were significantly correlated with CD68 immunostained areas (r=0.50, p=0.003). CONCLUSIONS: ADAMTS-1, -4 and -5 were present in human coronary atherosclerotic plaques, and ADATS-1 was more strongly expressed in AMI plaques than in stable plaques. ADAMTS-1 may play a role in plaque instability.