Gene expression-based prediction of myeloma cell sensitivity to histone deacetylase inhibitors.

BACKGROUND: Multiple myeloma (MM) is still a fatal plasma cell cancer. Novel compounds are currently clinically tested as a single agent in relapsing patients, but in best cases with partial response of a fraction of patients, emphasising the need to design tools predicting drug efficacy. Histone deacetylase inhibitors (HDACi) are anticancer agents targeting epigenetic regulation of gene expression and are in clinical development in MM. METHODS: To create a score predicting HDACi efficacy, five MM cell lines were treated with trichostatin A (TSA) and gene expression profiles were determined. RESULTS: The expression of 95 genes was found to be upregulated by TSA, using paired supervised analysis with Significance Analysis of Microarrays software. Thirty-seven of these 95 genes had prognostic value for overall survival in a cohort of 206 newly diagnosed MM patients and their prognostic information was summed up in a histone acetylation score (HA Score); patients with the highest HA Score had the shorter overall survival. It is worth noting that MM cell lines or patients' primary MM cells with a high HA Score had a significant higher sensitivity to TSA, valproic acid, panobinostat or vorinostat. CONCLUSION: In conclusion, the HA Score allows identification of MM patients with poor survival, who could benefit from HDACi treatment.

Bone morphogenic protein 6: a member of a novel class of prognostic factors expressed by normal and malignant plasma cells inhibiting proliferation and angiogenesis.

Pathogenesis of multiple myeloma is associated with an aberrant expression of pro-proliferative, pro-angiogenic and bone-metabolism-modifying factors by malignant plasma cells. Given the frequently long time span from diagnosis of early-stage plasma cell dyscrasias to overt myeloma and the mostly low proliferation rate of malignant plasma cells, we hypothesize these to similarly express a novel class of inhibitory factors of potential prognostic relevance. Bone morphogenic proteins (BMPs) represent possible candidates as they inhibit proliferation, stimulate bone formation and have an effect on the survival of cancer patients. We assessed the expression of BMPs and their receptors by Affymetrix DNA microarrays (n=779) including CD138-purified primary myeloma cell samples (n=635) of previously untreated patients. BMP6 is the only BMP expressed by malignant and normal plasma cells. Its expression is significantly lower in proliferating myeloma cells, myeloma cell lines or plasmablasts. BMP6 significantly inhibits the proliferation of myeloma cell lines, survival of primary myeloma cells and in vitro angiogenesis. A high BMP6 expression in primary myeloma cell samples delineates significantly superior overall survival for patients undergoing high-dose chemotherapy independent of conventional prognostic factors (International Staging System (ISS) stage, beta(2) microglobulin).

Gene expression profile of human endometrial receptivity: comparison between natural and stimulated cycles for the same patients.

BACKGROUND: The adjunction of exogenous hormones for controlled ovarian stimulation (COS) may alter endometrial receptiveness. In order to identify the genes misregulated under COS, we compared the endometrium gene expression profiles, from the same patients, in a natural cycle and in a subsequent COS cycle. METHODS: For the same normal-responder patients (n = 21), endometrial biopsies (n = 84) were collected during the pre-receptive (LH + 2) and receptive stages (LH + 7) of a natural cycle and, subsequently, on oocyte retrieval day (hCG + 2) and on transfer day (hCG + 5) of a stimulated cycle. Samples were analyzed using DNA microarrays. Gene expression profiles and biological pathways involved in endometrial receptivity were analyzed. RESULTS: Although endometrium transition profiles from pre-receptive to receptive phases are similar between patients, COS regimens alter endometrial receptivity in comparison with natural cycle. Under COS conditions, two endometrial profiles were identified and were associated either with a moderately altered receptivity profile for the majority of the patients or a strongly altered profile for a sub-category of patients. The receptive endometrium transcription profile under COS was defective for biological functions such as TGFbeta signaling, leukocyte transendothelial migration and the cell cycle. CONCLUSIONS: Gonadotrophin treatments in COS cycles led to disruptions of the transcriptional activation of genes involved in normal endometrial receptivity. We propose that when the receptiveness of the endometrium is seriously compromised by the COS protocol, fresh embryo replacement should be cancelled, the embryo frozen and thawed embryo replacement should be performed under natural cycles.

Identification of new biomarkers of human endometrial receptivity in the natural cycle.

BACKGROUND: Identification of new markers assessing endometrial receptivity may help in improving the clinical outcome of IVF. This study aimed at identifying genes expressed in human endometrium during the implantation window that could be used as such markers. METHODS: A series of normoresponder patients (n = 31) underwent endometrial biopsies (n = 62, 2 per patient) during the early secretory phase, 2 days after the LH surge (LH + 2) and the mid-secretory phase (LH + 7) of the same natural cycle that preceded a new ICSI attempt for male infertility factor. Samples were analyzed using DNA microarrays and gene expression profiles at the time of the implantation window were computed. Systems biology analysis allowed the identification of biological pathways that were over-represented in this signature. A new approach for class prediction applied to microarray experiments was then used to identify biomarkers putatively involved in endometrial receptiveness. RESULTS: Five genes expressed during the implantation window were all up-regulated in the LH + 7 samples compared with LH + 2 [laminin beta3 (P = 0.002), microfibril-associated protein 5 (P = 0.009), angiopoietin-like 1 (P = 0.005), endocrine gland-derived vascular endothelial growth factor (P = 0.049) and nuclear localized factor 2 (P = 0.007)]. Increased expression was validated by quantitative RT-PCR. CONCLUSIONS: Five genes have been identified for the first time as being up-regulated during the implantation window and are proposed as new biomarkers for exploration of endometrial receptiveness. As the endometrial biopsy procedure can be performed during a natural cycle, it would be worth testing this approach as a novel strategy in patients with poor implantation after IVF or ICSI.

Bone marrow mesenchymal stem cells are abnormal in multiple myeloma.

Recent literature suggested that cells of the microenvironment of tumors could be abnormal as well. To address this hypothesis in multiple myeloma (MM), we studied bone marrow mesenchymal stem cells (BMMSCs), the only long-lived cells of the bone marrow microenvironment, by gene expression profiling and phenotypic and functional studies in three groups of individuals: patients with MM, patients with monoclonal gamopathy of undefined significance (MGUS) and healthy age-matched subjects. Gene expression profile independently classified the BMMSCs of these individuals in a normal and in an MM group. MGUS BMMSCs were interspersed between these two groups. Among the 145 distinct genes differentially expressed in MM and normal BMMSCs, 46% may account for a tumor-microenvironment cross-talk. Known soluble factors implicated in MM pathophysiologic features (i.e. IL (interleukin)-6, DKK1) were revealed and new ones were found which are involved in angiogenesis, osteogenic differentiation or tumor growth. In particular, GDF15 was found to induce dose-dependent growth of MOLP-6, a stromal cell-dependent myeloma cell line. Functionally, MM BMMSCs induced an overgrowth of MOLP-6, and their capacity to differentiate into an osteoblastic lineage was impaired. Thus, MM BMMSCs are abnormal and could create a very efficient niche to support the survival and proliferation of the myeloma cells.

Heparan sulphate proteoglycans are essential for the myeloma cell growth activity of EGF-family ligands in multiple myeloma.

The epidermal growth factor (EGF)/EGF-receptor (ErbB1-4) family is involved in the biology of multiple myeloma (MM). In particular, ErbB-specific inhibitors induce strong apoptosis of myeloma cells (MMC) in vitro. To delineate the contribution of the 10 EGF-family ligands to the pathogenesis of MM, we have assessed their expression and biological activity. Comparing Affymetrix DNA-microarray-expression-profiles of CD138-purified plasma-cells from 65 MM-patients and 7 normal individuals to those of plasmablasts and B-cells, we found 5/10 EGF-family genes to be expressed in MMC. Neuregulin-2 and neuregulin-3 were expressed by MMC only, while neuregulin-1, amphiregulin and transforming growth factor-alpha were expressed by both MMC and normal plasma-cells. Using real-time polymerase chain reaction, we found HB-EGF, amphiregulin, neuregulin-1 and epiregulin to be expressed by cells from the bone marrow-environment. Only the EGF-members able to bind heparan-sulphate proteoglycans (HSPGs) - neuregulin-1, amphiregulin, HB-EGF - promote the growth of MMC. Those ligands strongly bind MMC through HSPGs. The binding and the MMC growth activity was abrogated by heparitinase, heparin or deletion of the HS-binding domain. The number of HS-binding EGF ligand molecules bound to MMC was higher than 10(5) molecules/cell and paralleled that of syndecan-1. Syndecan-1, the main HSPG present on MM cells, likely concentrates high levels of HS-binding-EGF-ligands at the cell membrane and facilitates ErbB-activation. Altogether, our data further identify EGF-signalling as promising target for MM-therapy.

Growth and immortalization of human myeloma cells in immunodeficient severe combined immunodeficiency mice: a preclinical model.

Human multiple myeloma (MM) purified tumour cells readily undergo apoptosis in vitro. Interleukin 6 (IL-6), a main growth factor of tumour cells, has enabled the development of IL-6-dependent MM cell lines. Recently, we developed anti-gp130 monoclonal antibodies (mAbs), two of which (B1 + I2) were able to dimerize gp130 and replace IL-6 in vitro. We show here that the injection of B1 + I2 IL-6 agonistic mAbs via the inguinal subcutaneous (SC) route efficiently produced tumours in severe combined immunodeficiency (SCID) mice grafted with IL-6-dependent myeloma cell lines compared with either the intraperitoneal (IP) or abdominal surgical bursa (SB) routes. The SC tumour graft, together with Matrigel and vascular endothelial growth factor (VEGF), leads to a strong vascularization and early detection of serum human immunoglobulins (huIgs). SCID mice treated with B1 + I2 mAbs were injected with fresh MM cells from five patients, four of whom had consistent levels of huIgs, and tumour growth was present in two. For one patient, tumour plasma cells that were passed several times subcutaneously in new SCID mice, still expressed their initial markers after several months. They remained unable to grow in vitro in the presence of B1 + I2 or IL-6. The nature of the SCID factors involved and the triggered genes are under investigation.

MBR rearrangement and P-glycoprotein expression are not independent prognostic factors like p53 protein in malignant lymphoma.

Non-Hodgkin's lymphomas (NHL) are B-cell malignancies which generally present molecular abnormalities, such as bcl-2 translocation t(14; 18) predominantly in the follicular subgroup. Other molecular events have been described in NHL, including p53 gene mutation and overexpression of one chemoresistance mechanism, the multidrug resistance system, P-glycoprotein (MDR 1/P-gp). In this study, we analysed samples from 44 NHL patients with the presence of the bcl-2 major breakpoint region (MBR) rearrangement in 29 and without in 15. Immunochemical analysis revealed that 39 samples were positive for bcl-2 protein expression in tumoral cells (88.6%). Seventeen (38.6%) patients expressed P-gp and 9 (20.5%) expressed p53 proteins. Eleven patients expressed both bcl-2 and P-gp proteins, four expressed bcl-2 and p53 proteins whereas four expressed bcl-2, p53 and P-gp proteins. Our results confirm the importance of p53 expression as a key prognostic factor, and no objective response (OR) was found in patients with p53 positivity. MBR rearrangement was not associated with poor response to chemotherapy (62.1% OR in MBR positive patients v. 60% OR in MBR negative patients). The clinical impact of P-gp cannot be identified because no relationship was observed between P-gp expression and prognosis (58.8% OR in P-gp positive patients v. 63% OR in P-gp negative patients).

Mutations of the p53 tumour suppressor gene in erosive rheumatoid synovial tissue.

Erosive rheumatoid arthritis (RA) is accompanied by synovial tissue hyperplasia associated with the proliferation of transformed-appearing synovial lining cells. In the present study we have analysed the expression of the p53 tumour suppressor gene in the synovial pannus tissue from patients at various stages of the disease. We used a combination of polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP) on DNA and reverse transcription, PCR and sequencing on cDNAs from synovial tissues or purified synovial cell populations of 24 RA and three osteoarthritis (OA) patients. We also studied p53 expression by immunohistochemical analysis. Mutations suspected after SSCP were identified by systematic sequencing of the p53 exon 6, especially in the fibroblast-like, adherent synovial cell population, associated with an erosive disease. Some accumulation of the protein was detected in immunohistochemical analysis of the p53 tumour suppressor gene in the patients' synovial tissues. However, no sign of malignancy was seen in these patients after a 2-year survey. These results show some abnormalities in the p53 tumour suppressor gene in RA patients, but do not allow this to be related to characteristic proliferative features of the rheumatoid synovium.

Mononuclear cell retention in rheumatoid synovial tissue engrafted in severe combined immunodeficient (SCID) mice is up-regulated by tumour necrosis factor-alpha (TNF-alpha) and mediated through intercellular adhesion molecule-1 (ICAM-1).

The aim of this study was to assess regulation of mononuclear cell (MNC) traffic to human synovial tissue by TNF-alpha and IL-1 and the involvement of ICAM-1 in MNC retention in rheumatoid synovial tissue. Human rheumatoid arthritis synovium was engrafted subcutaneously in 6-8 week-old SCID/CB17 mice. Three weeks later, we injected 20 x 10(6) human peripheral blood mononuclear cells (PBMC) previously labelled with 111indium intraperitoneally into mice containing control or cytokine-injected grafts. Total body scintigraphy was performed 72 h postinjection. The graft was removed and immunochemical analysis carried out to assess ICAM-1, vascular cell adhesion molecule-1 (VCAM-1) and E-selectin expression. In some experiments, mice were treated intravenously with 500 micrograms MoAb anti-ICAM-1 (BIRR-1) or an isotype-matched control MoAb before introduction of MNC. TNF-alpha, but not IL-1 alpha, enhanced MNC retention in the rheumatoid synovial graft 72 h post-injection (graft activity 989 +/- 1227 ct/min per 200 pixels or 3.36 +/- 4.16% of initial injected activity versus 411 +/- 157 ct/min per 200 pixels or 1.13 +/- 0.45% in controls; P < 0.03). TNF-alpha enhanced ICAM-1 expression by synovial cells and endothelial cells, whereas VCAM-1 or E-selectin expression was not enhanced on either cell type. After MoAb treatment of ICAM-1, synovial lymphocyte recruitment of TNF-alpha-treated mice decreased significantly to levels below that of control mice (160 +/- 97 ct/min per 200 pixels, 0.54 +/- 0.33%; P < 0.01). Mononuclear cell retention in rheumatoid synovial tissue engrafted into SCID mice was up-regulated by TNF-alpha and blocked by MoAb to ICAM-1. These results suggest that ICAM-1 is involved in mononuclear cell retention in rheumatoid synovium.

Growth factor activity of IL-6 in the synovial fluid of patients with rheumatoid arthritis.

OBJECTIVE: We set out to determine whether the ability of synovial fluids (SF) in patients with rheumatoid arthritis (RA) to facilitate the proliferation of synovial tissue-derived fibroblastic cell lines was related to the presence of growth factors and/or cytokines. METHODS: The growth factor activity of 20 RA SF was measured by their ability to induce anchorage-independent growth of the rat NRK-49F (49F) fibroblastic strain. The presence of transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF) was also assessed using neutralising anti-TGF-beta or anti-PDGF-AB mAbs. Cytokines were measured by functional assays or ELISA: RESULTS: We observed a correlation between growth factor activity and the IL-6 levels in SF. Both were correlated to the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in SF and serum. IL-6 (at concentrations above 10(4) U/ml), synergized with growth factors in the induction of the anchorage independent (AI) growth of 49F cells. Pretreatment of SF with a neutralising anti-IL-6 mAb substantially reduced the capacity of these SF to induce AI growth of 49F cells, confirming the growth factor activity of IL-6 in this test. In contrast, IL-6 alone or in association with PDGF, epidermal growth factor (EGF) or TGF-beta had no effect on the anchored growth of synovial tissue-derived fibroblasts, and treatment of SF with a neutralising anti-IL-6 mAb did not affect their ability to increase the growth rate of synovial tissue-derived fibroblasts. CONCLUSIONS: These results strongly suggest that IL-6 is responsible for the observed correlation between the growth factor activity of SF and inflammatory indexes such as ESR and CRP. However, neither IL-6 nor PDGF were responsible for the observed positive effect of SF on synovial fibroblastic cell lines.

Peripheral neuropathy after autologous blood stem cell transplantation for multiple myeloma.

We report a case of peripheral neuropathy occurring after autologous blood stem cell transplantation (ABSCT) for multiple myeloma. The patient, free of neurological symptoms, was transplanted in partial remission, and achieved a complete remission after transplantation. A severe peripheral, symmetric, distal sensori-motor polyneuropathy appeared at day 25 and worsened progressively until commencement of corticosteroid therapy. A peripheral nerve biopsy showed endoneurial cellular infiltrates which were predominantly composed of T cells identified by immunocytochemistry. Ultrastructural examination showed acute axonal damage. Electrophysiologic studies performed before and during the treatment were consistent with a severe axonal degeneration and showed a marked improvement, concomitant with the favorable clinical outcome. This is the first report of peripheral neuropathy after ABSCT.

Contrasting effect of transforming growth factor type beta 1 (TGF-beta 1) on proliferation and interleukin-2 receptor expression in activated and rapidly cycling immature (CD3-CD4-CD8-) thymocytes.

Transforming growth factor beta (TGF-beta) is a cytokine with immunoregulatory properties that acts negatively on T lymphocyte proliferation. However, with the EL 4-6.1 variant of the murine thymoma EL 4 activated with phorbol ester and/or interleukin-1 (IL-1), we recently found that it up-regulates interleukin-2-receptor (IL-2R) expression. Since EL 4-6.1 cells share phenotypic and functional characteristics with the immature thymic subset lacking CD4 and CD8 accessory molecules (DN), we investigated the effect of TGF-beta 1 on the IL-2R 55kD alpha chain expression and proliferation of activated DN cells and especially in DN cells that do not express CD3. We observed that TGF-beta 1 was able to increase both the percentage of CD3-DN cells expressing IL-2R alpha chains and the expression of IL-2R alpha chain in these cells. This stimulatory effect of TGF-beta 1 was distal from early transduction events. In addition, TGF-beta 1 was found to modulate CD3-DN cell proliferation. During differentiation in the thymus, CD3-DN cells transiently express the IL-2R alpha chain of the IL-2R and these IL-2R+ CD3-DN cells are preprogrammed to down-regulate the IL-2R alpha chain and up-regulate the CD4 and CD8 accessory molecule. We thus also tested the effect of TGF-beta 1 on IL-2R alpha chain expression in these in vitro differentiating CD3-DN cells. We found that TGF-beta 1 neither significantly affected IL-2R expression nor changed CD4 or CD8 expression. Hence, in CD3-DN cells, the effect of TGF-beta 1 on IL-2R expression seems to be restricted to proliferating cells.

In vitro primary allo-CTL generation by enucleated antigen-presenting cells.

It is generally thought that only viable cells can elicit a primary cytotoxic T-lymphocyte (CTL) response. We present evidence that this is not so, since enucleated tumor cells can generate a strong cytolytic response of unprimed allogeneic human T lymphocytes. Cytoplasts (enucleated cells) were obtained by incubation with cytochalasin B and subsequent isopycnic centrifugation. Their purity was assessed by electron microscopy and flow cytometry. Membrane fractions were prepared by nitrogen cavitation, and used in parallel with cytoplasts and intact cells as stimulators in primary allo-CTL generation; although all cell fractions expressed high amounts of class I and II histocompatibility antigens, as assessed by flow cytometry and ELISA technique, only the cytoplasts generated a strong cytotoxic response of naive peripheral T cells, like that induced by intact cells. The dogma that an intact and metabolically active stimulator cell is required for the primary generation of CTLs is questioned.

Stimulator cell requirements for allospecific T cell subsets: specialized accessory cells are required to activate helper but not cytolytic T lymphocyte precursors.

Murine cortisone-resistant thymocytes were separated by staining with monoclonal anti-Lyt-2 antibody and FMF into Lyt-2- and Lyt-2+ subsets in order to analyze the nature of stimulator accessory cells required to activate each of these functionally distinct T cell subpopulations. The Lyt-2- fraction was able to proliferate but not to generate cytotoxic cells when stimulated by irradiated allogeneic spleen cells. Fractionation of the stimulator population showed that low numbers of dendritic cells and splenic macrophages, but not equivalent numbers of whole spleen cells or peritoneal macrophages, were able to stimulate the Lyt-2- population. On the other hand, the Lyt-2+ population, which showed little if any proliferation in response to irradiated spleen cells, contained all the precursors of cytolytic T lymphocytes. In contrast to the highly specific stimulator requirement of the Lyt-2- fraction, allospecific cytotoxic cells were generated from Lyt-2+ cells by any alloantigen-bearing stimulator cell provided interleukin 2 was present. This was confirmed by limiting dilution analysis: alloreactive CTL-P frequencies in spleen and thymus were not influenced by the nature of the stimulator cell. These data collectively indicate that heterogeneous Ia+ accessory cells are required to stimulate helper but not cytolytic T cell precursors.

Use of concanavalin A to analyse the mechanism of memory cell differentiation into killer cells.

The renewing by ConA of the cytolytic activity evaluated in a short-term chromium release assay in a population of memory cells obtained in a long-term mixed lymphocyte culture is shown to be largely dependent upon the dose of ConA used; a three staged phenomenon in terms of dose response and kinetics is analysed and suggests that at least for low concentration of ConA (0.5 micrograms/ml) the lectin acts on the same subpopulation and through the same mechanism as the specific antigen, as shown by DNA-synthesis inhibition experiments. Preincubation with ConA at doses giving the best secondary-like response strongly inhibits further response to the primary alloantigen. Experiments using mixtures of ConA and alloantigens as stimulators show that both agents can compete in differentiating memory cells into killer cells. All these data suggest an important overlap of the structures on memory cells which are triggered by ConA or specific antigen.