The normal counterpart to the chronic lymphocytic leukemia B cell

Identification of Urine Biomarkers to Improve Eligibility for Prostate Biopsy and Detect High-Grade Prostate Cancer

Simple Summary

The screening of prostate cancer (PCa), based on the serum prostate specific antigen (PSA), is characterized by a high number of false positives, leading to overdiagnosis of healthy men and overtreatment of indolent PCa. This clinical problem severely affects the quality of life of patients, who would benefit from more specific risk stratification models. By performing a mass spectrometry (MS) screening on urine samples collected prior to prostate biopsy, we identified novel biomarkers and validated them by ELISA. Here, we show that an upfront urine test, based on quantitative biomarkers and patient age, has a higher performance compared to PSA (AUC = 0.6020) and is a feasible method to improve the eligibility criteria for prostate biopsy, to detect healthy men (AUC = 0.8196) and clinically significant PCa, thereby reducing the number of unnecessary prostate biopsies.

Abstract

PCa screening is based on the measurements of the serum prostate specific antigen (PSA) to select men with higher risks for tumors and, thus, eligible for prostate biopsy. However, PSA testing has a low specificity, leading to unnecessary biopsies in 50–75% of cases. Therefore, more specific screening opportunities are needed to reduce the number of biopsies performed on healthy men and patients with indolent tumors. Urine samples from 45 patients with elevated PSA were collected prior to prostate biopsy, a mass spectrometry (MS) screening was performed to identify novel biomarkers and the best candidates were validated by ELISA. The urine quantification of PEDF, HPX, CD99, CANX, FCER2, HRNR, and KRT13 showed superior performance compared to PSA. Additionally, the combination of two biomarkers and patient age resulted in an AUC of 0.8196 (PSA = 0.6020) and 0.7801 (PSA = 0.5690) in detecting healthy men and high-grade PCa, respectively. In this study, we identified and validated novel urine biomarkers for the screening of PCa, showing that an upfront urine test, based on quantitative biomarkers and patient age, is a feasible method to reduce the number of unnecessary prostate biopsies and detect both healthy men and clinically significant PCa.

Potential Relevance of B-cell Maturation Pathways in Defining the Cell(s) of Origin for Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a common, incurable disease of undefined cause. Notably, the normal cell equivalents of CLL cells remain elusive, and it is possible that the disease emanates from several normal B-cell subsets. This article reviews the literature relating to this issue, focusing on recent findings, in particular made through epigenetic analyses that strongly support the disease developing from a normal Ag-experienced and memory cell-like B lymphocyte. It also reports the known pathways whereby normal B lymphocytes mature after antigenic challenge and proposes that this information is relevant in defining the cells of origin of this disease.

Chronic Lymphocytic Leukemia B-Cell Normal Cellular Counterpart: Clues From a Functional Perspective

Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of small mature-looking CD19+ CD23+ CD5+ B-cells that accumulate in the blood, bone marrow, and lymphoid organs. To date, no consensus has been reached concerning the normal cellular counterpart of CLL B-cells and several B-cell types have been proposed. CLL B-cells have remarkable phenotypic and gene expression profile homogeneity. In recent years, the molecular and cellular biology of CLL has been enriched by seminal insights that are leading to a better understanding of the natural history of the disease. Immunophenotypic and molecular approaches (including immunoglobulin heavy-chain variable gene mutational status, transcriptional and epigenetic profiling) comparing the normal B-cell subset and CLL B-cells provide some new insights into the normal cellular counterpart. Functional characteristics (including activation requirements and propensity for plasma cell differentiation) of CLL B-cells have now been investigated for 50 years. B-cell subsets differ substantially in terms of their functional features. Analysis of shared functional characteristics may reveal similarities between normal B-cell subsets and CLL B-cells, allowing speculative assignment of a normal cellular counterpart for CLL B-cells. In this review, we summarize current data regarding peripheral B-cell differentiation and human B-cell subsets and suggest possibilities for a normal cellular counterpart based on the functional characteristics of CLL B-cells. However, a definitive normal cellular counterpart cannot be attributed on the basis of the available data. We discuss the functional characteristics required for a cell to be logically considered to be the normal counterpart of CLL B-cells.

Characterization of TET and IDH gene expression in chronic lymphocytic leukemia: comparison with normal B cells and prognostic significance

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most common hematological malignancy in western countries, characterized by a heterogeneous clinical course. Although genetic studies have identified chromosomal aberrations or specific mutations, epigenetic changes have been poorly characterized in CLL.

METHODS

We assessed ten-eleven translocations (TET) 1, 2, and 3, isocitrate dehydrogenase (IDH) 1, and 2 messenger RNA (mRNA) expression using real-time PCR on purified leukemic B cells from 214 CLL patients (median follow-up = 75 months, range 1-380), normal peripheral blood B cells (n = 20), and umbilical cord blood B cells (n = 21). The microenvironment influence was assessed after 24 h co-culture of CLL cells with bone marrow mesenchymal stromal cells (BMSC). Finally, 5-hydroxymethylcytosine level (%5-hmC) was assessed by ELISA in CLL cells alone or with microenvironment stimuli.

RESULTS

TET 1 and 3 and IDH2 were decreased in CLL cells compared with healthy B cells (P = 0.0221, 0.0013, <0.0001, respectively), while IDH1 was overexpressed (P = 0.0037). TET2 and IDH1 were significantly correlated with treatment-free survival (TFS); patients with high TET2/IDH1 expression had a higher median TFS (111 months) than patients with low expression (78 months, P = 0.0071/0.0123). Moreover, TET1 expression decreased (P = 0.0371), while TET3 and IDH2 expression increased (P = 0.0273/0.0039) in co-cultures. However, %5-hmC was not correlated with clinical data and was unchanged following microenvironment stimuli.

CONCLUSIONS

Despite a slight deregulation in CLL cells compared with normal B cells, we identified a significant association between TET/IDH gene expression and prognosis, suggesting that epigenetic changes could potentially be associated with disease progression. Moreover, despite an identical %5-hmC, TET gene expression was influenced by contact with BMSC confirming the crucial role of the microenvironment in CLL pathogenesis.

CTLA-4 affects expression of key cell cycle regulators of G0/G1 phase in neoplastic lymphocytes from patients with chronic lymphocytic leukaemia

Previously, we showed that cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) is overexpressed in chronic lymphocytic leukaemia (CLL) and its expression is correlated with the expression of the major regulators of G1 phase progression: cyclins D2 and D3, and cyclin-dependent kinase inhibitory protein 1 (p27 (KIP1) ). In the present study, we blocked CTLA-4 on the surface of both CLL cells and normal B lymphocytes to investigate the impact of CTLA-4 on the expression of the mentioned G1 phase regulators. We found that in CLL patients and in healthy individuals, the median proportions of cyclin D2-positive cells as well as cyclin D3(+) cells significantly decreased following CTLA-4 blockade. Moreover, CTLA-4 blockade led to an increase in the median frequencies of p27 (KIP1) -positive cells, although this increase was marked only in CLL patients. Our study showed that CTLA-4 affects the expression of the key regulators of G1 phase progression in CLL cells as well as in normal B lymphocytes and may contribute to a better understanding of the role of CTLA-4 in the regulation of G1 phase progression.

The clinical significance of DC-SIGN and DC-SIGNR, which are novel markers expressed in human colon cancer

Background

Colon cancer has always been diagnosed at a late stage, which is associated with poor prognosis. The currently used serum tumor markers CEA and CA19-9 display low sensitivity and specificity and may not have diagnostic value in early stage colon cancer. Thus, there is an urgent need to identify novel serum biomarkers for use in the early detection of colon cancer.

Methods

In this study, the expression of DC-SIGN and DC-SIGNR in serum was detected by enzyme-linked immunosorbent assay (ELISA). DC-SIGN and DC-SIGNR expression was detected in cancer tissues by immunohistochemistry (IHC).

Results

The level of sDC-SIGN was lower in patients than in the healthy controls, while the level of sDC-SIGNR in patients was higher than in the healthy controls. Both sDC-SIGN and sDC-SIGNR had diagnostic significances for cancer patients, and the combined diagnosis of these two markers was higher than both of them alone. Furthermore, there were significant differences between both sDC-SIGN and sDC-SIGNR in stage I/II patients and the healthy controls. Moreover, high sDC-SIGN level was accompanied with the long survival time. Additionally, DC-SIGNR was negative in the cancer foci and matched normal colon tissues but was weakly positive between the cancer foci. DC-SIGN staining was faint in matched normal colon tissues, strong in the tumor stroma and the invasive margin of colon cancer tissues, and negatively correlated with the sDC-SIGN level in serum from the same patient. Interestingly, the percent survival of patients with a DC-SIGN mean density of>0.001219 (the upper 95% confidence interval of matched normal colon tissues) was higher than for all other patients.

Conclusion

DC-SIGN and DC-SIGNR are blood-based molecular markers that can potentially be used for the diagnosis of early stage patients. Moreover, expression of DC-SIGN in serum and cancer tissues may affect the survival time for colon cancer patients.

Morphology and expression status investigations of specific surface markers on B-cell chronic lymphocytic leukemia cells

The morphology of cells and expression status of specific surface markers [cluster of differentiation (CD)], such as CD5, CD19, CD20, CD38, and CD45, have long been considered as the essential indicators for the diagnosis and prognosis of B-cell chronic lymphocytic leukemia (B-CLL). Clinically, it is difficult to simultaneously obtain cell morphology and distribution of surface markers with flow cytometry, especially for some surrogate markers such as CD38. Here, as an alternative and complementary prognostic method, fluorescence microscopy and image processing method are introduced to directly visualize the cells from patients and to quantitatively determine the expression status of surface markers. In this study, the morphological parameters of B-CLL cells were measured to establish the correlation between the cellular morphology and the surface marker expression. It was clear that the CD38+ and CD38- B-CLL cells from the same CD38+ patients had hardly any size differences; however, an increase in perimeter was observed for CD38- patients. Moreover, the expression level of the receptors on the cell was independent of the cell size. There was no evidence showing that the expression intensities of CD19 and CD38 were related to each other for the CD38+ B-CLL cells. On the same cells, CD5 was more selectively expressed on the cell membrane; however, the expression patterns suggested that the cell membrane of CD38- B-CLL cells contained the least expression level of CD19.

A combination of cytokines rescues highly purified leukemic CLL B-cells from spontaneous apoptosis in vitro

B-chronic lymphocytic leukemia (B-CLL), the most common human leukemia, is characterized by predominantly non-dividing malignant mature CD5+ B lymphocytes with an apoptosis defect. Various microenvironmental stimuli confer a growth advantage on these leukemic cells and extend their survival in vivo. Nevertheless, when cultured in vitro, CLL B-cells rapidly die from apoptosis. Certain cytokines may extend the survival capacity of CLL B-cells in vitro and individual anti-apoptotic effects of several cytokines have been reported. The potential cumulative effect of such cytokines has not been studied. We therefore investigated the effects on CLL B-cells survival in vitro of humoral factors, polyclonal lymphocyte activators and a combination of cytokines known for their anti-apoptotic effects. Purified CLL B-cells were cultured in the presence or absence of various soluble molecules and the leukemic cell response was assessed in terms of viability. Apoptotic cell death was detected by flow cytometry using annexinV and 7-amino-actinomycin. The survival of CLL B-cells in vitro was highly variable. When tested separately, cytokines (IL-2, -6, -10, -12, -15, -21, BAFF and APRIL) improved CLL B cell survival moderately; in combination, they significantly enhanced survival of these cells, even up to 7 days of culture. We also report that humoral factors from autologous serum are important for survival of these malignant cells. Our findings support the concept that the CLL microenvironment is critical and suggest that soluble factors may contribute directly to the prolonged survival of CLL B-cells. Therefore, the combination of cytokines we describe as providing strong resistance to apoptosis in vitro might be used to improve the treatment of CLL.

HDAC isoenzyme expression is deregulated in chronic lymphocytic leukemia B-cells and has a complex prognostic significance

Histone deacetylases (HDACs) play a crucial role in chromatin structure and, consequently, gene expression. Their deregulation has been reported in various cancers. We performed a complete and comprehensive study of the expression of 18 HDACs (including Sirtuin; SIRT) by real-time PCR in a cohort of 200 chronic lymphocytic leukemia (CLL) patients with a median follow-up of 77 mo, and compared it with the results obtained from normal B cells. We also compared HDAC expression at diagnosis and after relapse. We observed significant deregulation (mostly upregulation) of HDACs in CLL. In terms of clinical significance, only HDAC6 was significantly correlated with treatment-free survival (TFS), whereas HDAC3 and SIRT2, 3 and 6 were correlated with overall survival (OS). A multivariate Cox regression stepwise analysis indicated that HDAC6, 7 and 10 and SIRT3 were TFS independent predictors. Interestingly, poor prognosis was associated with an overexpression of HDAC7 and 10 but an underexpression of HDAC6 and SIRT3. Therefore, these factors were combined in a TFS score: patients with a score of 0-1-2, 3 and 4 had a median TFS of 107, 57 and 26 mo, respectively (HR = 4.03, p < 0.0001). For OS, SIRT5 and 6 allowed stratification into 3 groups, with a median OS of > 360, 237 and 94 mo (HR = 6.38, p < 0.0001). However, we could not find statistical differences in HDAC expression after relapse. These results, validated by a 5-fold cross-validation, highlight the complex impact of HDAC expression in CLL clinical course.

Systemic in vivo lentiviral delivery of miR-15a/16 reduces malignancy in the NZB de novo mouse model of chronic lymphocytic leukemia

Similar to human chronic lymphocytic leukemia (CLL), the de novo New Zealand Black (NZB) mouse model has a genetically determined age-associated increase in malignant B-1 clones and decreased expression of microRNAs miR-15a and miR-16 in B-1 cells. In the present study, lentiviral vectors were employed in vivo to restore miR-15a/16, and both the short-term single injection and long-term multiple injection effects of this delivery were observed in NZB. Control lentivirus without the mir-15a/16 sequence was used for comparison. We found that in vivo lentiviral delivery of mir-15a/16 increased miR-15a/16 expression in cells that were transduced (detected by GFP expression) and in sera when compared with control lentivirus treatment. More importantly, mice treated with the miR-expressing lentivirus had decreased disease. The lentivirus had little systemic toxicity while preferentially targeting B-1 cells. Short-term effects on B-1 cells were direct effects, and only malignant B-1 cells transduced with miR-15a/16 lentivirus had decreased viability. In contrast, long-term studies suggested both direct and indirect effects resulting from miR-15a/16 lentivirus treatment. A decrease in B-1 cells was found in both the transduced and non-transduced populations. Our data support the potential use of systemic lentiviral delivery of miR-15a/16 to ameliorate disease manifestations of CLL.

The New Zealand black mouse as a model for the development and progression of chronic lymphocytic leukemia

BACKGROUND

Similar to a subset of human patients who progress from monoclonal B lymphocytosis (MBL) to chronic lymphocytic leukemia (CLL), New Zealand Black (NZB) mice have an age-associated progression to CLL. The murine disease is linked to a genetic abnormality in microRNA mir-15a/16-1 locus, resulting in decreased mature miR-15a/16.

METHODS

Spleens of aging NZB were analyzed for the presence of B-1 cells via flow cytometry and for the presence of a side population (SP) via the ability of cells to exclude Hoechst 33342 dye. The SP was assayed for the presence of hyperdiploid B-1 clones and for the ability to differentiate into B-1 cells in vitro and transfer disease in vivo. In addition, enhanced apoptosis of chemoresistant NZB B-1 cells was examined by restoring miR-16 levels in nutlin-treated cells.

RESULTS

Aging NZB mice develop a B-1 expansion and clonal development that evolves from MBL into CLL. An expansion in SP is also seen. Although the SP did contain increased cells with stem cell markers, they lacked malignant B-1 cells and did not transfer disease in vivo. Similar to B-1 cells, splenic NZB SP also has decreased miR-15a/16 when compared with C57Bl/6. Exogenous addition of miR-15a/16 to NZB B-1 cells resulted in increased sensitivity to nutlin.

CONCLUSION

NZB serve as an excellent model for studying the development and progression of age-associated CLL. NZB SP cells do not seem to contain cancer stem cells, but rather the B-1 stem cell. NZB B-1 chemoresistance may be related to reduced miR-15a/16 expression.

CD23/FcεRII: molecular multi-tasking

CD23 is the low-affinity receptor for immunoglobulin (Ig)E and plays important roles in the regulation of IgE responses. CD23 can be cleaved from cell surfaces to yield a range of soluble CD23 (sCD23) proteins that have pleiotropic cytokine-like activities. The regions of CD23 responsible for interaction with many of its known ligands, including IgE, CD21, major histocompatibility complex (MHC) class II and integrins, have been identified and help to explain the structure-function relationships within the CD23 protein. Translational studies of CD23 underline its credibility as a target for therapeutic intervention strategies and illustrate its involvement in mediating therapeutic effects of antibodies directed at other targets.

The B-cell tumor-associated antigen ROR1 can be targeted with T cells modified to express a ROR1-specific chimeric antigen receptor

Monoclonal antibodies and T cells modified to express chimeric antigen receptors specific for B-cell lineage surface molecules such as CD20 exert antitumor activity in B-cell malignancies, but deplete normal B cells. The receptor tyrosine kinase-like orphan receptor 1 (ROR1) was identified as a highly expressed gene in B-cell chronic lymphocytic leukemia (B-CLL), but not normal B cells, suggesting it may serve as a tumor-specific target for therapy. We analyzed ROR1-expression in normal nonhematopoietic and hematopoietic cells including B-cell precursors, and in hematopoietic malignancies. ROR1 has characteristics of an oncofetal gene and is expressed in undifferentiated embryonic stem cells, B-CLL and mantle cell lymphoma, but not in major adult tissues apart from low levels in adipose tissue and at an early stage of B-cell development. We constructed a ROR1-specific chimeric antigen receptor that when expressed in T cells from healthy donors or CLL patients conferred specific recognition of primary B-CLL and mantle cell lymphoma, including rare drug effluxing chemotherapy resistant tumor cells that have been implicated in maintaining the malignancy, but not mature normal B cells. T-cell therapies targeting ROR1 may be effective in B-CLL and other ROR1-positive tumors. However, the expression of ROR1 on some normal tissues suggests the potential for toxi-city to subsets of normal cells.

The autocrine motility factor receptor is overexpressed on the surface of B cells in Binet C chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a heterogeneous disease with a clinical spectrum reaching from discrete lymphocytosis to extensive enlargement of lymph nodes, spleen and liver, and bone marrow failure. The aim of this study was to identify genes that differentiate between patients with disease stage A vs. C according to Binet in order to better understand the disease. To achieve this, we performed DNA microarray analysis on B cells from CLL patients with stage A and C according to Binet and matched controls. Between CLL patients and controls, there were 1,528 differentially expressed genes and 360 genes were differentially expressed between Binet A and C patients. Due to the sheer number of regulated genes, we focused on the autocrine motility factor receptor (AMFR). AMFR has not previously been investigated in hematological disorders, but high expression of AMFR correlates with a more advanced stage and invasive potential in several human tumors. AMFR mRNA expression was higher in Binet A compared with Binet C patients (P=0.0053) and healthy controls (P=0.0051). Total AMFR protein was higher in Binet A patients compared to Binet C as analyzed by intracellular flow cytometry. However, AMFR exist both in the ER involved in protein degradation and on the cell surface involved in metastasis and cell motility. Cell surface AMFR was increased in Binet C compared with Binet A+B (P=0.016). In conclusion, the mRNA levels reflect the total amount of AMFR, whereas cell surface expression is associated with progression in CLL.

The clinical and biological features of a series of immunophenotypic variant of B-CLL

OBJECTIVES

To describe the clinical and biological features of a series of immunophenotypic variant of B-CLL (v-CLL) characterised by intermediate RMH score, in the absence of t(11;14)(q13;q32) in FISH analysis in comparison with a series of typical CLL.

METHODS

We studied the clinical and biological features of 63 cases of v-CLL and 130 cases of CLL.

RESULTS

We observed significant differences in terms of age <70 yr (P < 0.001), lymphocytosis <20 x 10(9)/L (P < 0.001), lymphocyte doubling time <or=12 months (P = 0.02), high serum beta2-microglobulin levels (P < 0.001) and splenomegaly (P = 0.002); CD38, CD49d, CD1c were more expressed in v-CLL, CD43 in CLL (P < 0.001). IgV(H) mutation and trisomy 12 were more frequent in v-CLL group (P = 0.001; P < 0.001); del13q14 in CLL (P = 0.008). Gene expression profiling of nine v-CLL and 60 CLL indicated that the atypical group presented a specific molecular pattern. After a median follow-up of respectively, 55 (4-196) and 60 months (6-180), 25/42 patients with v-CLL (48%) and 55/93 patients with CLL (59%) were treated. Time to treatment was significantly shorter in IgV(H)-mutated v-CLL vs. mutated CLL (P = 0.006). The median overall survival was worse in v-CLL-mutated cases (P = 0.062).

CONCLUSION

v-CLL should be identified and dealt with separately from classic CLL. In particular, the prognostic markers that are routinely used to characterise classical B-CLL should not be interpreted as having the same meaning.

Epigenetic regulation of WNT signaling in chronic lymphocytic leukemia

Certain WNT and WNT network target genes are expressed at higher or lower levels in chronic lymphocytic leukemia compared with normal B-cells. This includes upregulation of nuclear complex genes, as well as genes for cytoplasmic proteins and WNT ligands and their cognate receptors. In addition, epigenetic silencing of several negative regulators of the WNT pathway have been identified. The balance between epigenetic downregulation of negative effector genes and increased expression of positive effector genes demonstrate that the epigenetic downregulation of WNT antagonists is one mechanism, perhaps the main mechanism, that is permissive to active WNT signaling in chronic lymphocytic leukemia. Moreover, constitutive activation of the WNT network and target genes is likely to impact on additional interacting signaling pathways. Based on published studies, we propose a model of WNT signaling that involves mainly permissive expression, and sometimes overexpression, of positive effectors and downregulation of negative regulators in the network. In this model, DNA methylation, histone modifications and altered expression of microRNA molecules interact to allow continuous WNT signaling.

Extensive intraclonal diversification in a subgroup of chronic lymphocytic leukemia patients with stereotyped IGHV4-34 receptors: implications for ongoing interactions with antigen

Several studies indicate that the development of chronic lymphocytic leukemia (CLL) may be influenced by antigen recognition through the clonotypic B-cell receptors (BCRs). However, it is still unclear whether antigen involvement is restricted to the malignant transformation phase or whether the putative antigen(s) may continuously trigger the CLL clone and affect not only the progenitor cell but also the leukemic cells themselves. To address this issue, we conducted a large-scale subcloning study of rearranged immunoglobulin heavy variable (IGHV) genes of diverse mutational status from 71 CLL cases (total, 1496 subcloned sequences), belonging to both the common IgM/IgD variant and the rare IgG-positive variant. Although most cases showed no or low levels of intraclonal diversification (ID), we report intense ID in the IGHV genes of selected cases, especially a subgroup of 13 IgG-switched cases expressing stereotyped, mutated IGHV4-34 rearrangements (subset 4). We demonstrate that the ID evident in subset 4 cases cannot be attributed to IGHV4-34 usage, IGHV gene-mutated status, class-switch recombination, or BCR stereotypy in general; rather, it represents a unique phenomenon strongly correlated with the distinctive BCR of subset 4. In such cases, the observed ID patterns may imply a stereotyped response to an active, ongoing interaction with antigen(s).

Correcting miR-15a/16 genetic defect in New Zealand Black mouse model of CLL enhances drug sensitivity

Alterations in the human 13q14 genomic region containing microRNAs mir-15a and mir-16-1 are present in most human chronic lymphocytic leukemia (CLL). We have previously found the development of CLL in the New Zealand Black murine model to be associated with a point mutation in the primary mir-15a/16-1 region, which correlated with a decrease in mature miR-16 and miR-15a levels. In this study, addition of exogenous miR-15a and miR-16 led to an accumulation of cells in G(1) in non-New Zealand Black B cell and New Zealand Black-derived malignant B-1 cell lines. However, the New Zealand Black line had significantly greater G(1) accumulation, suggesting a restoration of cell cycle control upon exogenous miR-15a/16 addition. Our experiments showed a reduction in protein levels of cyclin D1, a miR-15a/16 target and cell cycle regulator of G(1)/S transition, in the New Zealand Black cell line following miR-15a/16 addition. These microRNAs were shown to directly target the cyclin D1 3' untranslated region using a green fluorescent protein lentiviral expression system. miR-16 was also shown to augment apoptosis induction by nutlin, a mouse double minute 2 (MDM2) antagonist, and genistein, a tyrosine kinase inhibitor, when added to a B-1 cell line derived from multiple in vivo passages of malignant B-1 cells from New Zealand Black mice with CLL. miR-16 synergized with nutlin and genistein to induce apoptosis. Our data support a role for the mir-15a/16-1 cluster in cell cycle regulation and suggest that these mature microRNAs in both the New Zealand Black model and human CLL may be targets for therapeutic efficacy in this disease.

Intrinsic and extrinsic factors influencing the clinical course of B-cell chronic lymphocytic leukemia: prognostic markers with pathogenetic relevance

B-cell chronic lymphocytic leukemia (CLL), the most frequent leukemia in the Western world, is characterized by extremely variable clinical courses with survivals ranging from 1 to more than 15 years. The pathogenetic factors playing a key role in defining the biological features of CLL cells, hence eventually influencing the clinical aggressiveness of the disease, are here divided into "intrinsic factors", mainly genomic alterations of CLL cells, and "extrinsic factors", responsible for direct microenvironmental interactions of CLL cells; the latter group includes interactions of CLL cells occurring via the surface B cell receptor (BCR) and dependent to specific molecular features of the BCR itself and/or to the presence of the BCR-associated molecule ZAP-70, or via other non-BCR-dependent interactions, e.g. specific receptor/ligand interactions, such as CD38/CD31 or CD49d/VCAM-1. A putative final model, discussing the pathogenesis and the clinicobiological features of CLL in relationship of these factors, is also provided.

Molecular cloning and expression analysis of pig CD79alpha

The CD79alpha (immunoglobulin alpha, Igalpha), a part of B cell receptor (BCR) complex, forms a heterodimer with CD79beta (Igbeta) and plays an important role in the B cell signaling. In this study, we have cloned pig Cd79a cDNA using RT-PCR and determined the complete cDNA sequence of pig Cd79a. Pig Cd79a cDNA contains an open reading frame (672bp) encoding 223 amino acids. The putative amino acid identity of pig CD79alpha with those of human, cattle and mouse are 70.4, 81.4, and 67.7%, respectively. Alignment of the CD79alpha amino acid sequence with those of mammalian species showed that the extracellular domain is the most divergent, whereas transmembrane region and cytoplasmic tail including immunoreceptor tyrosine-based activation motif (ITAM) are largely conserved. Pig Cd79a mRNA was detected mainly in lymphoid tissues by RT-PCR. The highest level of Cd79a mRNA expression was observed in mesenteric lymph node and spleen. Relatively low level of Cd79a mRNA expression was observed in lung, thymus and small intestine. The lowest level of Cd79a mRNA expression was observed in large intestine. Flow cytometry analyses demonstrated that human CD79alpha antibody recognizes a CD79alpha in pig B cells. Further, immunohistochemistry analysis using human CD79alpha antibody on pig spleen was revealed that CD79alpha is strongly expressed in the follicular mantle zone rather than in the germinal center. Future study will be focused on defining the functional role of CD79alpha during the course of pig infectious diseases and the formation of neoplasm.