Chromosomally clonal T cells in the skin, blood, or lymph nodes of two Sezary syndrome patients express CD45RA, CD45RO, CDw150, and interleukin-4, but no interleukin-2 or interferon-gamma

Inhibition of integrin αVβ3 signaling improves the antineoplastic effect of bexarotene in cutaneous T-cell lymphoma

Bexarotene is a specific RXR agonist that has been used for the treatment of cutaneous T-cell lymphoma (CTCL). Since bexarotene causes hypothyroidism, it requires the administration of levothyroxine. However, levothyroxine, in addition to its ubiquitous nuclear receptors, can activate the αVβ3 integrin that is overexpressed in CTCL, potentially interfering the antineoplastic effect of bexarotene. We thus investigated the biological effect of levothyroxine in relation to bexarotene treatment. Although in isolated CTCL cells levothyroxine decreased, in an αVβ3 -dependent manner, the antineoplastic effect of bexarotene; levothyroxine supplementation in pre-clinical models was necessary to avoid suppression of lymphoma immunity. Accordingly, selective genetic and pharmacologic inhibition of integrin αVβ3 3 improved the antineoplastic effect of bexarotene plus levothyroxine replacement while maintaining lymphoma immunity. Our results provide a mechanistic rationale for clinical testing of integrin αVβ3 inhibitors as part of CTCL regimens based on bexarotene administration.

Cutaneous T-cell lymphoma-associated lung cancers show chromosomal aberrations differing from primary lung cancer

Cutaneous T-cell lymphoma (CTCL) patients have an increased risk of certain secondary cancers, the most common of which are lung cancers, especially small cell lung cancer. To reveal the molecular pathogenesis underlying CTCL-associated lung cancer, we analyzed genomic aberrations in CTCL-associated and reference lung cancer samples. DNA derived from microdissected lung cancer cells of five CTCL-associated lung cancers and five reference lung cancers without CTCL association was analyzed by comparative genomic hybridization (CGH). Fluorescent in situ hybridization (FISH), immunohistochemistry (IHC), and loss of heterozygosity (LOH) analysis were performed for selected genes. In CTCL-associated lung cancer, CGH revealed chromosomal aberrations characterizing both lung cancer and CTCL, but also losses of 1p, and 19, and gains of 4q and 7, hallmarks of CTCL. LOH for the CTCL-associated NAV3 gene was detected in two of the four informative primary lung cancers. FISH revealed increased copy number of the KIT gene in 3/4 of CTCL-associated lung cancers and 1/5 of primary lung cancers. PDGFRA and VEGFR2 copy numbers were also increased. IHC showed moderate KIT expression when the gene copy number was increased. CTCL-associated lung cancer shows chromosomal aberrations different from primary lung cancer, especially amplifications of 4q, a chromosome arm frequently deleted in the latter tumor type. Copy numbers and expression of selected genes in chromosome 4 differed between CTCL-associated and reference lung cancers. These preliminary observations warrant further prospective studies to identify the common underlying factors between CTCL and CTCL-associated lung cancer.

Common chromosomal abnormalities in mycosis fungoides transformation

To identify cytogenetic features of large cell transformation in mycosis fungoides (T-MF), we selected in 11 patients, 16 samples either from skin tumors (13), lymph node (1), or peripheral blood cells (2) collected at the time of the transformation. Comparative genomic hybridization (CGH), G-banding, fluorescence in situ hybridisation (FISH), multicolour FISH (mFISH), and DNA content analysis were used. Fifteen samples displayed unbalanced CGH profiles, with gains more frequently observed than losses. Recurrent chromosomal alterations were observed for chromosomes 1, 2, 7, 9, 17, and 19. The most common imbalances were gain of chromosome regions 1p36, 7, 9q34, 17q24-qter, 19, and loss of 2q36-qter, 9p21, and 17p. In six samples 1p36-pter gain was associated with 9q34-qter gain and whole chromosome 19 gain. In five of these samples whole or partial gain of chromosome 17 was also observed. No specific pattern was seen with regard to the expression of the CD30 antigen by tumor cells. Cytogenetics and/or DNA content analysis of skin tumor cells revealed an abnormal chromosome number in all tested cases (n = 7) with DNA ploidy ranging from hyperdiploid (2.78) to hypotetraploid (3.69) (mean 3.14+/-0.38). Thus, T-MF displayed frequent chromosomal imbalances associated with hypotetraploidy.

Th1 Response and Cytotoxicity Genes Are Down-Regulated in Cutaneous T-Cell Lymphoma

PURPOSE

Increased production of Th2 cytokines characterizes Sezary syndrome, the leukemic form of cutaneous T-cell lymphomas (CTCL). To identify the molecular background and to study whether shared by the most common CTCL subtype, mycosis fungoides, we analyzed the gene expression profiles in both subtypes.

EXPERIMENTAL DESIGN

Freshly isolated cells from 30 samples, representing skin, blood, and enriched CD4(+) cell populations of mycosis fungoides and Sezary syndrome, were analyzed with Affymetrix (Santa Clara, CA) oligonucleotide microarrays, quantitative PCR, or immunohistochemistry. The gene expression profiles were combined with findings of comparative genomic hybridization of the same samples to identify chromosomal changes affecting the aberrant gene expression.

RESULTS

We identified a set of Th1-specific genes [e.g., TBX21 (T-bet), NKG7, and SCYA5 (RANTES)] to be down-regulated in Sezary syndrome as well as in a proportion of mycosis fungoides samples. In both Sezary syndrome and mycosis fungoides blood samples, the S100P and LIR9 gene expression was up-regulated. In lesional skin, IL7R and CD52 were up-regulated. Integration of comparative genomic hybridization and transcriptomic data identified chromosome arms 1q, 3p, 3q, 4q, 12q, 16p, and 16q as likely targets for new CTCL-associated gene aberrations.

CONCLUSIONS

Our findings revealed several new genes involved in CTCL pathogenesis and potential therapeutic targets. Down-regulation of a set of genes involved in Th1 polarization, including the major Th1-polarizing factor, TBX21, was for the first time associated with CTCL. In addition, a plausible explanation for the proliferative response of CTCL cells to locally produced interleukin-7 was revealed.

Biological Insights into the Pathogenesis of Cutaneous T-Cell Lymphomas (CTCL)

Mycosis fungoides and Sezary syndrome, collectively known as cutaneous T-cell lymphomas (CTCLs), are low-grade, indolent, clonal, non-Hodgkin's lymphomas consisting of CD4+ CD45RO+ T cells with a CLA+ CCR4+ skin-homing phenotype. There are several variants of primary CTCLs with differences in clinical behavior and prognosis. Currently, the precise etiologies of mycosis fungoides and Sezary syndrome are unknown. This article reviews our current understanding of the pathogenetic abnormalities involving genomic mutations, abnormal cDNA expression, and dysregulation of signaling pathways in CTCL.

Primary Cutaneous T-Cell Lymphomas Show a Deletion or Translocation AffectingNAV3, the HumanUNC-53Homologue

Multicolor fluorescent in situ hybridization (FISH) was used to identify acquired chromosomal aberrations in 12 patients with mycosis fungoides or Sézary syndrome, the most common forms of primary cutaneous T-cell lymphoma (CTCL). The most frequently affected chromosome was 12, which showed clonal deletions or translocations with a break point in 12q21 or 12q22 in five of seven consecutive Sézary syndrome patients and a clonal monosomy in the sixth patient. The break point of a balanced translocation t(12;18)(q21;q21.2), mapped in the minimal common region of two deletions, fine mapped to 12q2. By locus-specific FISH, the translocation disrupted one gene, NAV3 (POMFIL1), a human homologue of unc-53 in Caenorhabditis elegans. A missense mutation in the remaining NAV3 allele was found in one of six cases with a deletion or translocation. With locus-specific FISH, NAV3 deletions were found in the skin lesions of four of eight (50%) patients with early mycosis fungoides (stages IA-IIA) and in the skin or lymph node of 11 of 13 (85%) patients with advanced mycosis fungoides or Sézary syndrome. Preliminary functional studies with lentiviral small interfering RNA-based NAV3 silencing in Jurkat cells and in primary lymphocytes showed enhanced interleukin 2 expression (but not CD25 expression). Thus, NAV3 may contribute to the growth, differentiation, and apoptosis of CTCL cells as well as to the skewing from Th1-type to Th2-type phenotype during disease progression. NAV3, a novel putative haploinsufficient tumor suppressor gene, is disrupted in most cases of the commonest types of CTCL and may thus provide a new diagnostic tool.

Cellular coincidence of clonal T cell receptor rearrangements and complex clonal chromosomal aberrations-a hallmark of malignancy in cutaneous T cell lymphoma

Detection of a clonal T cell receptor (TCR) gene rearrangement is used in the diagnosis of primary cutaneous T cell lymphomas (CTCL) whereas chromosomal aberrations serve as a diagnostic tool for leukaemias and nodal lymphomas. To what extent both approaches specify the same cell population remains unknown. We investigated the coincidence of TCR clonality with complex clonal chromosomal aberrations, indicating qualitative alteration of the affected cells, in 17 CTCL patients. Out of 41 skin, blood, and lymph node samples studied, 34 gave results in chromosome and TCR analyses. With 88%, most specimens revealed corresponding results by both techniques (27 of 34 clonal, three of 34 non-clonal). In two patients, analysis of micro-dissected cells demonstrated that neoplastic T cells bear both a dominant TCR rearrangement and a complex chromosomal aberration. The cutaneous clone was found in blood samples of 11 of 12 patients (including early stages), and investigation of follow-up skin and blood samples indicated persistence of the T cell clone in 11 of 14 cases. In conclusion, we show that dominant TCR clones and chromosomal clones converge in all stages of CTCL. These clones disseminate into blood and skin at early disease stages and persist despite therapy. The coexistence of a dominant TCR clone and a clonal chromosomal aberration can thus be used as a hallmark of malignancy.

The use of anti-T-cell receptor-Vbeta antibodies for the estimation of treatment success and phenotypic characterization of clonal T-cell populations in cutaneous T-cell lymphomas

Sézary syndrome and Mycosis fungoides are the most common forms of cutaneous T-cell lymphomas. To assess the response to different therapies especially in Sézary syndrome, it is helpful to monitor the percentage of circulating tumour cells in the blood. The use of T-cell receptor (TCR)-Vbeta specific monoclonal antibodies provides a suitable tool for detecting Sézary cells. In this study, we analysed the levels of clonal CD4+Vbeta+ cells of seven patients with various treatment modalities using flow cytometry and investigated the immunophenotype of the clonal cells by double staining with a panel of antibodies recognizing lymphatic surface markers. Additionally, a polymerase chain reaction-denaturing gradient gel electrophoresis assay was performed on clonal CD4+Vbeta2+ cells, showing that these cells carry a Vgamma10/11, JgammaP1/2 TCR rearrangement. Follow-up studies revealed close association of the Vbeta+ clone developmentwith the clinical response to different therapiesinsixpatients. Intwo cases, the CD4+Vbeta+ cells decreased accompanied by partial regression or even complete remission. In four cases, a stable or increasing clonal CD4+Vbeta+ population reflected well a stable or progressing course of the disease. Double staining of Vbeta+ cells revealed the following pattern, CD3+, CD5+, CD7+, CD28+, CD80-, CD86+ and human leucocyte antigen (HLA) class I+. In contrast, HLA-DR was heterogeneously expressed. We conclude that identification and monitoring of CD4+Vbeta+ clonal T cells by fluorescence-activated cell sorting with double staining is a suitable method to assess clinical responses to different therapies.

Proapoptotic and antiapoptotic markers in cutaneous T-cell lymphoma skin infiltrates and lymphomatoid papulosis

BACKGROUND

In cutaneous T-cell lymphoma (CTCL) lesions, both reactive T cells and malignant T cells intermingle. The disease progression is mostly slow. Recent evidence suggests that even if clinical remission is reached, malignant cells persist and a relapse follows sooner or later. To wha extent tumour cell apoptosis occurs in the skin lesions either due to the reactive T cells or t therapeutic efforts is not known.

OBJECTIVES

To determine the extent of tumour cell apoptosis and the expression of proapoptotic an antiapoptotic markers in serial skin lesion samples from patients with CTCL, and to compare th findings with those in patients with lymphomatoid papulosis (LyP).

METHODS

Thirty-four skin samples were obtained from 12 patients with CTCL at the time o diagnosis and at a mean of 1.6, 3 and 6 years later. The patients received psoralen plus ultraviolet (PUVA), electron beam or cytostatic treatments. In addition, fresh post-treatment samples fro three patients with CTCL undergoing PUVA therapy were obtained. For comparison, skin biopsies o five patients with LyP were studied. Immunohistochemical demonstration of the expression of th following markers was performed on formalin-fixed skin sections: Fas (CD95), Fas ligand (FasL) bcl-2, granzyme B, the tumour-suppressor protein PTEN and the effector caspase, caspase-3. Th malignant cells were identified morphologically, and apoptotic cells were identified with th terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling method on parallel sections.

RESULTS

In untreated CTCL lesions, apoptotic lymphocytes were extremely rare, and no increase in the number of apoptotic cells was observed after any of the treatments used. In LyP, apoptotic cell were more frequent, comprising on average 5% of the infiltrate. The apoptosis-associated marker Fas, FasL, caspase-3 and granzyme B were expressed by morphologically neoplastic cells in CTCL and by large atypical cells in LyP, with no significant differences. However, only a few reactive cell in CTCL infiltrates expressed granzyme B while about 10% of the corresponding cells were positive in LyP. The expression of antiapoptotic bcl-2 was more frequent in CTCL than in LyP, while PTE expression was high in both instances. The number of bcl-2 + cells tended to decrease after therapy When comparing the findings between the first and the last samples, a decrease in the number of bcl-2+ cells and an increase in Fas+ cells was associated with disease progression, despite therapy, while the opposite was true for remissions.

CONCLUSIONS

Apoptosis was found to be a rare event in CTCL lesions irrespective of precedin therapy During patient follow-up, no significant differences in the expression of apoptotic marker was observed while in most cases a lower level of antiapoptotic bcl-2 expression was observed after all types of therapies and in association with disease progression when compared with high expression in the untreated lesions. The absence of apoptosis and high expression of bcl-2 together with a low expression of apoptosis-inducing granzyme B in the reactive lymphocytes in CTC could explain the chronic nature of the disease and the poor response to therapy, while th more frequent occurrence of granzyme B and apoptosis together with a lower level of expressio of bcl-2 by the large atypical cells in LyP could contribute to the favourable outcome of the latter.