FOXP1 suppresses immune response signatures and MHC class II expression in activated B-cell-like diffuse large B-cell lymphomas.

The FOXP1 (forkhead box P1) transcription factor is a marker of poor prognosis in diffuse large B-cell lymphoma (DLBCL). Here microarray analysis of FOXP1-silenced DLBCL cell lines identified differential regulation of immune response signatures and major histocompatibility complex class II (MHC II) genes as some of the most significant differences between germinal center B-cell (GCB)-like DLBCL with full-length FOXP1 protein expression versus activated B-cell (ABC)-like DLBCL expressing predominantly short FOXP1 isoforms. In an independent primary DLBCL microarray data set, multiple MHC II genes, including human leukocyte antigen DR alpha chain (HLA-DRA), were inversely correlated with FOXP1 transcript expression (P<0.05). FOXP1 knockdown in ABC-DLBCL cells led to increased cell-surface expression of HLA-DRA and CD74. In R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone)-treated DLBCL patients (n=150), reduced HLA-DRA (<90% frequency) expression correlated with inferior overall survival (P=0.0003) and progression-free survival (P=0.0012) and with non-GCB subtype stratified by the Hans, Choi or Visco-Young algorithms (all P<0.01). In non-GCB DLBCL cases with <90% HLA-DRA, there was an inverse correlation with the frequency (P=0.0456) and intensity (P=0.0349) of FOXP1 expression. We propose that FOXP1 represents a novel regulator of genes targeted by the class II MHC transactivator CIITA (MHC II and CD74) and therapeutically targeting the FOXP1 pathway may improve antigen presentation and immune surveillance in high-risk DLBCL patients.

Reciprocal expression of the endocytic protein HIP1R and its repressor FOXP1 predicts outcome in R-CHOP-treated diffuse large B-cell lymphoma patients.

We previously identified autoantibodies to the endocytic-associated protein Huntingtin-interacting protein 1-related (HIP1R) in diffuse large B-cell lymphoma (DLBCL) patients. HIP1R regulates internalization of cell surface receptors via endocytosis, a process relevant to many therapeutic strategies including CD20 targeting with rituximab. In this study, we characterized HIP1R expression patterns, investigated a mechanism of transcriptional regulation and its clinical relevance in DLBCL patients treated with immunochemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone, R-CHOP). HIP1R was preferentially expressed in germinal center B-cell-like DLBCL (P<0.0001) and inversely correlated with the activated B-cell-like DLBCL (ABC-DLBCL) associated transcription factor, Forkhead box P1 (FOXP1). HIP1R was confirmed as a direct FOXP1 target gene in ABC-DLBCL by FOXP1-targeted silencing and chromatin immunoprecipitation. Lower HIP1R protein expression (≤ 10% tumoral positivity) significantly correlated with inferior overall survival (OS, P=0.0003) and progression-free survival (PFS, P=0.0148) in R-CHOP-treated DLBCL patients (n=157). Reciprocal expression with ≥ 70% FOXP1 positivity defined FOXP1(hi)/HIP1R(lo) patients with particularly poor outcome (OS, P=0.0001; PFS, P=0.0016). In an independent R-CHOP-treated DLBCL (n=233) microarray data set, patients with transcript expression in lower quartile HIP1R and FOXP1(hi)/HIP1R(lo) subgroups exhibited worse OS, P=0.0044 and P=0.0004, respectively. HIP1R repression by FOXP1 is strongly associated with poor outcome, thus further understanding of FOXP1-HIP1R and/or endocytic signaling pathways might give rise to novel therapeutic options for DLBCL.

DNA vaccines to target the cancer testis antigen PASD1 in human multiple myeloma.

We previously described PASD1 as a new cancer testis antigen in multiple myeloma (MM) that is retained post-therapy, suggesting the use of vaccination strategies to induce anti-PASD1 immunity in a setting of minimal residual disease. We have focused on DNA fusion gene vaccines, coupling fragment C domain (DOM) of tetanus toxin with PASD1 sequence, and examined efficacy in Human Leukocyte Antigen (HLA)-A2 (HHD) transgenic mice using a human MM cell line expressing PASD1 protein and chimeric HLA-A2 class I molecules as target. DNA vaccines encoded two HLA-A2-restricted epitopes (p.DOM-PASD1(1), p.DOM-PASD1(2)) and full-length PASD1 (p.DOM-PASD1FL). p.DOM-PASD1(1) proved superior to p.DOM-PASD1(2) in generating T-cell responses in HHD mice, able to lyse the chimeric murine RMA-HHD cells. Boosting by electroporation significantly enhanced p.DOM-PASD1(1). Only p.DOM-PASD1(1) induced cytotoxic T-lymphocytes (CTLs) were able to lyse human MM target cells expressing endogenous antigen. The p.DOM-PASD1FL vaccine predominantly induced strong PASD1(1) over PASD1(2) T-cell immune responses, indicative of immunodominance. Importantly, p.DOM-PASD1FL generated immune-mediating killing of native chimeric MM cells, in the absence of exogenous added peptide, implicating PASD1(1) specific CTLs. These data demonstrate that PASD1-derived epitopes are both efficiently and selectively processed and presented by native human MM cells. Notably, they permit the use of PASD1-encoding DNA vaccine therapy in a clinical setting.

Targeted phototherapy of plaque-type psoriasis using ultraviolet B-light-emitting diodes.

BACKGROUND: One of the major technological breakthroughs in the last decade is represented by the diversified medical applications of light-emitting diodes (LEDs). LEDs emitting in the ultraviolet (UV) B spectrum might serve as a more convenient alternative for targeted delivery of phototherapy in inflammatory skin diseases such as psoriasis. OBJECTIVES: We investigated the efficacy and safety of a new UVB-LED phototherapeutic device in chronic plaque-type psoriasis. METHODS: Twenty patients with stable plaque-type psoriasis were enrolled into a prospective, right-left comparative, open study. Symmetrical lesions located on extremities or trunk were chosen; one lesion was treated with the study device, whereas the other lesion served as an untreated control. Two treatment regimens were used in the study, one with an aggressive dose escalation similar to those used for outpatient treatment and one with slow increase in dose, similar to those used for treatment at home. RESULTS: Patients in both groups responded rapidly to the UVB-LED therapy. Early disease resolution was observed in 11 patients (seven in the first group and four in the second group). Overall improvement at end of therapy was 93% in the high-dose group and 84% in the low-dose group. Four patients from the high-dose group and five from the low-dose group were still in remission at the 6-month follow-up visit. CONCLUSIONS: These results suggest that this innovative UVB-LED device is effective in the treatment of localized psoriasis and may be useful in other UV-responsive skin diseases.

Expression of the forkhead box transcription factor FOXP1 is associated with oestrogen receptor alpha, oestrogen receptor beta and improved survival in familial breast cancers.

BACKGROUND: The role of FOXP1 in sporadic breast cancers has been widely studied but its role in familial breast cancers is yet unexplored. AIMS: To investigate FOXP1 expression in different molecular subtypes of familial breast cancers and to correlate its expression with clinicopathological parameters, oestrogen receptors (ER) and survival. METHODS: Immunohistochemical staining for FOXP1 was performed in 126 familial breast carcinomas comprising 35 BRCA1, 34 BRCA2 and 57 BRCAX. RESULTS: Nuclear FOXP1 expression ranged from focal weak to widespread strong expression. Expression of FOXP1 was higher in familial breast cancers (54%) compared with sporadic cancers (46%) (p<0.001). There was a significant correlation between FOXP1 with ERalpha (p = 0.038) and ERbeta (p = 0.007) in familial breast cancers. FOXP1 was more highly expressed in familial breast cancers compared with sporadic cancers for luminal (p = 0.021) and basal (p<0.001), but not HER2 and null phenotypes (both p>0.05). The absence of FOXP1 expression was associated with a shorter relapse-free (p = 0.025) and overall survival (p = 0.009) in familial breast cancer. Negativity for FOXP1 was associated with a significantly worse overall survival in BRCA2 cancers (p = 0.021) and there was a non-significant separation of the survival curves for BRCA1 cancers (p = 0.183). No differences in survival were seen for BRCAX cancers (p = 0.762). CONCLUSION: Results suggest that FOXP1 demonstrates different expression patterns in familial breast cancers than sporadic tumours, even in tumours showing similar phenotypes. They also suggest a different role of FOXP1 as a tumour suppressor in familial tumours, which is unrelated to ER expression and may impact on therapeutic options.

Regulatory T cells in atopic dermatitis: epidermal dendritic cell clusters may contribute to their local expansion.

BACKGROUND: Regulatory T cells (Tregs) have an essential role in tolerance and immune regulation. However, few and controversial data have been published to date on the role and number of these cells in atopic dermatitis (AD). OBJECTIVES: To investigate the number of CD4+CD25+FOXP3+ Tregs and interleukin 10-producing T regulatory type 1 (Tr1) cells in patients with AD. METHODS: Peripheral blood and skin biopsy samples from atopy patch test (APT)-positive patients with acute- and chronic-phase AD were investigated. Immunohistochemistry was applied to identify CD4+CD25+FOXP3+ Tregs in the skin, while flow cytometry was used to detect CD4+CD25highFOXP3+ Tregs and Tr1 cells in the peripheral blood. RESULTS: In the peripheral blood samples of patients with AD significantly elevated numbers of Tr1 cells were found. Although neither the absolute number nor the percentage of CD4+CD25highFOXP3+ Tregs showed significant alteration in the peripheral blood of patients, increased numbers of FOXP3+ Tregs were detected in skin biopsy specimens. All of the APT-positive skin samples showed epidermal dendritic cell aggregates, morphologically consistent with so-called Langerhans cell microgranulomas, which also contained intermingled FOXP3+ Tregs. CONCLUSIONS: Tr1 cell numbers were elevated in the peripheral blood and increased numbers of CD4+CD25highFOXP3+ Tregs were detected in the skin of patients with AD. The epidermal dendritic cell clusters in APT-positive lesional skin showed a close connection to the FOXP3+ Tregs.

Pathway activation patterns in diffuse large B-cell lymphomas.

Deregulation of cell signaling pathways controlling cell growth and cell survival is a common feature of all cancers. Although a core repertoire of oncogenic mechanisms is widely conserved between various malignancies, the constellation of pathway activities can vary even in patients with the same malignant disease. Modern molecularly targeted cancer drugs intervene in cell signaling compensating for pathway deregulation. Hence characterizing tumors with respect to pathway activation will become crucial for treatment decisions. Here we have used semi-supervised machine learning methodology to generate signatures of eight oncogene-inducible pathways, which are conserved across epithelial and lymphoid tissues. We combined them to patterns of pathway activity called PAPs for pathway activation patterns and searched for them in 220 morphologically, immunohistochemically and genetically well-characterized mature aggressive B-cell lymphomas including 134 cases with clinical data available. Besides Burkitt lymphoma, which was characterized by a unique pattern, the PAPs identified four distinct groups of mature aggressive B-cell lymphomas across independent gene expression studies with distinct biological characteristics, genetic aberrations and prognosis. We confirmed our findings through cross-platform analysis in an independent data set of 303 mature aggressive B-cell lymphomas.

Absence of cyclin-D2 and Bcl-2 expression within the germinal centre type of diffuse large B-cell lymphoma identifies a very good prognostic subgroup of patients.

AIMS: To validate and improve the existing algorithm (proposed by Hans et al.) to classify diffuse large B-cell lymphoma (DLBCL). METHODS AND RESULTS: Tissue microarrays constructed from 81 patients with DLBCL were studied by immunohistochemistry for expression of CD10, Bcl-6, MUM1, Bcl-2, cyclin-D2, FOXP1 and PKC-gamma proteins. Cases were classified as either germinal centre B-like (GCB) or non-GC according to Hans et al. An alternative classification was also employed, in which cases positive for either CD10 or Bcl-6 were considered as a GC subgroup and cases negative for both CD10 and Bcl-6 were considered as a non-GC subgroup. GC was further subdivided into favourable GC (negative for both Bcl-2 and cyclin-D2) and unfavourable GC (positive for either Bcl-2 or cyclin-D2). The 5-year event-free survival (EFS) amongst patients classified as favourable GC versus 'others' was 49.5% and 7.3%, respectively (log rank P < 0.0001). Similarly, the 5-year overall survival (OS) amongst patients classified as favourable GC versus 'others' was 58.6% and 13.7%, respectively (log rank P = 0.0001). The difference in survival was independent of the international prognostic index. CONCLUSIONS: In this group of patients the risk stratification based on the new algorithm was better than that proposed by Hans et al.

FMIP controls the adipocyte lineage commitment of C2C12 cells by downmodulation of C/EBP alpha.

Fms interacting protein (FMIP) is a substrate for Fms tyrosine kinase, and a nuclear/cytoplasm shuttling protein with a leucine zipper. As the phosphorylation of FMIP is observed in insulin-stimulated preadipocytes, we examined the role of FMIP in adipocyte differentiation, using the mesenchymal multipotent stem cells, C2C12 cells, that can differentiate into adipocytes, muscle cells and osteoblasts. Ectopic expression of FMIP in C2C12 impairs the adipocyte differentiation induced by treatment with insulin, dexamethasone and 3-isobutyl-1-methylxanthine. These cells exhibit muscle phenotype with multinuclear morphology. Furthermore, knockdown of endogenous FMIP expression by small interfering RNA improves adipocytic lineage commitment of C2C12 cells, while impairing muscle differentiation. Upon stimulation with insulin, CCAAT/enhancer binding protein (C/EBP)beta, but not C/EBPalpha, is upregulated in cells expressing ectopic FMIP, whereas in FMIP knockdown cells, C/EBPalpha is constitutively expressed. Ectopic expression of C/EBPalpha counteracts the effects of FMIP, whereas C/EBPalpha knockdown partially mimics the effects of FMIP in this system. Northern blot analysis and reverse transcriptase-polymerase chain reaction study reveal that ectopic FMIP-expressing cells do not contain the polyadenylated C/EBPalpha mRNA, but contain the C/EBPalpha pre-mRNA, suggesting that FMIP plays a role in RNA processing and/or export. Indeed, a member of the THO complex that plays a role in mRNA export, THOC1, is co-precipitated with FMIP. The data we have acquired on FMIP suggest that it is a target for tyrosine kinase receptors that potentiate mRNA export.

Paucity of FOXP3+ cells in skin and peripheral blood distinguishes Sézary syndrome from other cutaneous T-cell lymphomas.

Cutaneous T-cell lymphomas (CTCL) are mainly comprised of two variants: mycosis fungoides (MF) with CD4(+) tumor cells confined to the skin and the leukemic Sézary syndrome with tumor cell spread to the blood. In this study, we investigated cutaneous expression of the regulatory T-cell (T(reg)) marker FOXP3 in 30 CTCL patients. Immunohistochemical analysis revealed significantly lower numbers of CD4(+)FOXP3(+) cells within the dermal lymphomononuclear infiltrate of Sézary patients (16% FOXP3(+) cells of CD4(+) cells) in contrast to MF (43% FOXP3(+) cells (P<0.05)) and rare types of CTCL (45% FOXP3(+) cells). Furthermore, CD4(+)FOXP3(+) T cells were also markedly reduced in the CD4(+) population within the peripheral blood of Sézary patients compared to controls as determined by fluorescence-activated cell sorter, quantitative PCR and functional analyses. The data support the conclusion that the neoplastic cells in CTCL do not express the T(reg) marker FOXP3. Our data also identify Sézary syndrome as, to our knowledge, the first reported neoplastic disease with a clear reduction in T(reg) numbers within the CD4(+) population. This lack of T(reg) might account for the more aggressive nature of Sézary syndrome compared with other CTCL.

Application of the FICTION technique for the simultaneous detection of immunophenotype and chromosomal abnormalities in routinely fixed, paraffin wax embedded bone marrow trephines.

The use of interphase fluorescence in situ hybridisation (FISH) to study cytogenetic abnormalities in routinely fixed paraffin wax embedded tissue has become commonplace over the past decade. However, very few studies have applied FISH to routinely fixed bone marrow trephines (BMTs). This may be because of the acid based decalcification methods that are commonly used during the processing of BMTs, which may adversely affect the suitability of the sample for FISH analysis. For the first time, this report describes the simultaneous application of FISH and immunofluorescent staining (the FICTION technique) to formalin fixed, EDTA decalcified and paraffin wax embedded BMTs. This technique allows the direct correlation of genetic abnormalities to immunophenotype, and therefore will be particularly useful for the identification of genetic abnormalities in specific tumour cells present in BMTs. The application of this to routine clinical practice will assist diagnosis and the detection of minimal residual disease.

FOXP3, a selective marker for a subset of adult T-cell leukaemia/lymphoma.

FOXP3 is a forkhead transcription factor family member, implicated in T-cell regulation, activation and differentiation. FOXP3 has been shown to be a master control gene for the development and function of CD4+/CD25+ regulatory T-cells (T(reg)). In this study, FOXP3 protein expression has been analysed using a new anti-FOXP3 monoclonal antibody in 172 paraffin-embedded lymphoma samples. FOXP3 expression in tumour cells was confined to adult T-cell leukaemia/lymphoma (ATLL) cases (17/25, 68%), with some variability in the intensity of the staining and the proportion of positive cells. No other lymphoma types studied exhibited FOXP3 expression in the malignant population. The selective expression of FOXP3 by tumour cells in ATLL makes this antibody a potentially useful diagnostic tool.

A novel diffuse large B-cell lymphoma-associated cancer testis antigen encoding a PAS domain protein.

Here we report that the OX-TES-1 SEREX antigen, which showed immunological reactivity with serum from four out of 10 diffuse large B-cell lymphoma (DLBCL) patients, is encoded by a novel gene, PAS domain containing 1 (PASD1). PASD1_v1 cDNA encodes a 639 amino-acid (aa) protein product, while an alternatively spliced variant (PASD1_v2), lacking intron 14, encodes a 773 aa protein, the first 638 aa of which are common to both proteins. The PASD1-predicted protein contains a PAS domain that, together with a putative leucine zipper and nuclear localisation signal, suggests it encodes a transcription factor. The expression of PASD1_v1 mRNA was confirmed by RT-PCR in seven DLBCL-derived cell lines, while PASD1_v2 mRNA appears to be preferentially expressed in cell lines derived from non-germinal centre DLBCL. Immunophenotyping studies of de novo DLBCL patients' tumours with antibodies to CD10, BCL-6 and MUM1 indicated that two patients mounting an immune response to PASD1 were of a poor prognosis non-germinal centre subtype. Expression of PASD1 mRNA was restricted to normal testis, while frequent expression was observed in solid tumours (25 out of 68), thus fulfilling the criteria for a novel cancer testis antigen. PASD1 has potential for lymphoma vaccine development that may also be widely applicable to other tumour types.

The FOXP1 winged helix transcription factor is a novel candidate tumor suppressor gene on chromosome 3p.

The JC12 monoclonal antibody recognizes a previously unknown nuclear protein that showed a restricted distribution in normal tonsil and was also overexpressed in a subset of diffuse large B-cell lymphomas. Using this reagent, we expression cloned cDNAs encoding its antigenic target and identified this protein as a novel putative transcription factor, FOXP1. The FOXP1 protein sequence contains predicted domains characteristic of transcription factors, including a winged helix DNA-binding motif, a second potential DNA-binding motif, a C(2)H(2) zinc finger, nuclear localization signals, coiled-coil regions, PEST sequences, and potential transactivation domains. The FOXP1 gene has been mapped to chromosome 3p14.1, a region that commonly shows loss of heterozygosity in a wide range of tumors and which is reported to contain a tumor suppressor gene(s). Using tissue arrays and immunohistochemistry, we demonstrate that both the FOXP1 mRNA and protein are widely expressed in normal tissues. The levels of FOXP1 mRNA were compared in paired normal and tumor tissues (from the same patient) using a tissue array containing cDNAs extracted from 68 samples taken from kidney, breast, prostate, uterus, ovary, cervix, colon, lung, stomach, rectum, small intestine, and from nine cancer cell lines. Differences in FOXP1 mRNA expression between normal and tumor samples were observed in 51% of cases. Most striking was the comparative loss of expression in 73% of colon tumors and comparative overexpression of FOXP1 mRNA in 75% of stomach tumors. Analysis of the FOXP1 mRNA expression in normal tissues (not taken from cancer patients) indicated that loss of FOXP1 expression may occur in some histologically normal tissues adjacent to tumors. Immunohistochemical analysis of FOXP1 protein expression was performed on 128 solid tumors, including 16 renal, 9 breast, 12 lung, 20 colon, 21 stomach, 10 head and neck, 35 prostate, and 5 pancreatic cases. Complete loss of expression, increased expression, and cytoplasmic mislocalization of the predominantly nuclear FOXP1 protein were frequently observed in neoplastic cells. Our study identifies FOXP1 as a new candidate tumor suppressor gene localized to the chromosome 3p14.1 region.

Immune response to the ALK oncogenic tyrosine kinase in patients with anaplastic large-cell lymphoma.

Oncogenic anaplastic lymphoma kinase (ALK) fusion proteins (nucleophosmin-ALK [NPM-ALK] and other variants) are expressed in many cases of anaplastic large-cell lymphoma (ALCL) but are absent from normal tissues. The possibility that ALK proteins are immunogenic was investigated with the use of an immunocytochemical technique to screen plasma from ALK-positive ALCL on transfectants expressing ALK proteins and by an in vitro kinase assay. Circulating antibodies against NPM-ALK protein were present in all ALK-positive ALCL patients (11 out of 11 cases) studied while 10 patients also had antibodies recognizing normal ALK protein. Weak antibodies reactive with NPM-ALK (which may represent anti-NPM autoantibodies) were detected by the in vitro kinase assay in 3 of the 10 control samples (but not by immunocytochemistry). The presence of anti-ALK antibodies may be relevant to the relatively good prognosis of ALK-positive ALCL. The immunocytochemical technique for detecting anti-ALK activity is simple and semiquantative and may provide a means of detecting B-cell responses to other tumor-associated molecules. (Blood. 2000;96:1605-1607)

Identification of the CD85 antigen as ILT2, an inhibitory MHC class I receptor of the immunoglobulin superfamily.

The CD85 molecule was originally defined at the Fifth Workshop on Leucocyte Antigens in 1993 by two monoclonal antibodies, VMP55 and GHI/75. This cell-surface glycoprotein is expressed on B cells, monocytes, and subpopulations of T and natural killer (NK) cells, and particularly high levels are expressed by normal and neoplastic plasma cells and by hairy cell leukemia B cells. We affinity purified the CD85 antigen and obtained tryptic peptide sequence which indicated that this molecule might be ILT2, a recently described inhibitory major histocompatibility complex class I receptor of the immunoglobulin superfamily. This was confirmed by showing that both of the original anti-CD85 mAbs stained ILT2 transfectants. The cell signaling role demonstrated for ILT2 is consistent with the previously reported involvement of CD85 in T cell activation.