Investigating Novel Food Sensitization: A Real-Life Prevalence Study of Cricket, Locust, and Mealworm IgE-Reactivity in Naïve allergic Individuals

BACKGROUND AND OBJECTIVE

With the global population on the rise, edible insects are considered a potential solution to food security, although concerns about risks such as anaphylaxis exist.

METHODS

2,014 participants underwent testing with the Allergy Explorer-ALEX-2 including extracts of three novel foods: Acheta Domesticus (Ad), Locusta migratoria (Lm), and Tenebrio molitor (Tm). The IgE-mediated sensitization status was investigated in participants who had never knowingly consumed these insects. Data was recorded using an electronic database.

RESULTS

195 individuals (9.7% of all participants) were sensitized to insects. Tropomyosin was co-recognized by 34%, and 18.5% were positive for arginine kinases. Reactivity to Sarcoplasmic-CB, Troponin-C, Paramyosin, or Myosin-light-chain was found in less than 5% of the population, whereas 108 individuals (55.4%) did not show any reactivity to invertebrate panallergens. Additionally, 33 individuals (16.9%) exhibited monosensitization exclusively to insects. Multivariate analysis revealed an inverse association between arachnid reactivity and sensitization to insect allergens, while Mollusca, Blattoidea, and tropomyosin reactivity displayed a direct relationship. Furthermore, Myosin-light-chain reactivity correlated with Ad and Lm, and Troponin-C with Ad and Tm sensitization.

CONCLUSION

Edible insect extract IgE sensitization was observed in individuals without prior exposure to such foods. Mites showed a low likelihood of being primary sensitizers due to their inverse association with insect reactivity. Conversely, the direct association of insect sensitization with mollusk and cockroach extract reactivity suggests their potential as primary sensitizers in these participants. Tropomyosin consistently exhibited a positive association with reactivity to all studied insects, supporting its role as a primary sensitizer.

Clinical severity of LTP syndrome is associated with an expanded IgE repertoire, FDEIA, FDHIH, and LTP mono reactivity

Summary

Background. LTP allergy is often a challenge for clinicians. We evaluated a multiplex diagnostic approach with diverse cofactors to stratify LTP syndrome risk. Methods. Of the 1,831 participants screened with 'Allergy Explorer-ALEX-2', 426 had reactions to at least one LTP. Data was gathered and recorded via an electronic database. Results. Reactivity to peach Pru p 3 was found in 77% of individuals with LTP allergy. Higher levels of specific IgE and concurrent sensitization to more than 5 molecules (50% of all LTP-sensitised participants, 62% of symptomatic cases) were significantly associated with an increased risk of severe reactions (p = 0.001). Several cofactors, either alone or in combination, also influenced patients' clinical outcomes. Some cofactors increased the risk of severe reactions, such as mono reactivity to LTP in 44.6% of cases (p = 0.001), FDEIA in 10.8% of patients (p = 0.001), and FDNIH in 11.5% (p = 0.005). On the other hand, reactivity to PR10 (24.2%; p = 0.001), profilin hypersensitivity (10.3%; p = 0.001), and/or atopic dermatitis (16.7%; p = 0.001) had a mitigating effect on symptom severity. Conclusions. Clinical severity of LTP syndrome is associated with an expanded IgE repertoire in terms of the number of LTP components recognized and increased IgE levels in individual molecules. Ara h 9, Cor a 8, and Mal d 3 showed the strongest association with clinical severity. In addition, several cofactors may either exacerbate (FDEIA, FDHIH, and LTP monoreactivity) or ameliorate (atopic dermatitis and co-sensitization to profilin and/or PR10) individual patient outcomes. These factors may be utilized for the daily clinical management of LTP syndrome.

A spindle cell neoplasm with MYH9::EGFR fusion and co-expression of S100 and CD34, further expanding the family of kinase fusion positive spindle cell neoplasms

Soft tissue neoplasms displaying CD34 and S100 positivity with immunohistochemistry are rare with a wide morphological range and frequent neurotrophic tyrosine receptor kinase (NTRK) alterations. Recent reports describe fusions in other kinases besides NTRK in these tumors. In the present article, we report a case of a young male suffering from a soft tissue neoplasm in the lumbar region. At microscopic examination, it was a CD34 and S100-positive soft tissue tumor showing a multilobulated growth pattern composed of cells with pale cytoplasm and abundant normal smooth muscle stroma. The genetic profile showed two alterations affecting EGFR gene represented by a novel MYH9::EGFR fusion transcript and a p.K714N mutation.

Human papilomaviru-related oropharyngeal squamous cell carcinoma and radiomics: A new era?

BACKGROUND

The increase of the incidence of human papillomavirus dependent oropharyngeal squamous cell carcinoma is alarming, although we have greatly progressed in the classification and staging of this disease. We now know that human papillomavirus related oropharyngeal squamous cell carcinoma is a sub-type of head and neck squamous cell carcinoma with favourable prognosis and good response to therapy that needs a proper system of classification and staging. Thus, in routine practice it is essential to test patients for the presence of human papillomavirus. The most popular technique to assess human papillomavirus status is immunohistochemistry on biopsy samples with p16, which is an excellent surrogate for high-risk human papillomavirus infection. Another highly sensitive and specific tissue-based technique for the detection of human papillomavirus is RNAscope In situ hybridization that has a prohibitive cost, limiting its use in routine practice. Radiomics is an artificial intelligence based non-invasive method of computational analysis of computed tomography, magnetic resonance imaging, positron emission tomography, and ultrasound images.

METHODS

In this review, we summarise the last findings of radiomics applied to human papillomavirus associated oropharyngeal squamous cell carcinoma.

RESULTS

A growing body of evidence suggest that radiomics is able to characterise and detect early relapse after treatment, and enable development of tailored therapy of human papillomavirus positive oropharyngeal squamous cell carcinoma.

IgE Sensitization Profile in Patients with Netherton Syndrome

BACKGROUND

Scant data are currently available on the allergen-specific immunoglobulin (Ig)E sensitization profile in primary immunodeficiencies with hyper IgE. Netherton syndrome (NS, OMIM 266500) is an extremely rare form of congenital ichthyosis characterized by congenital scaly erythroderma, hair abnormalities, and deregulated IgE reactivity associated with severe atopic manifestations.

OBJECTIVE

The aim of this study was to evaluate the feasibility and reliability of a multiplex proteomic approach in the detection of specific IgE in NS.

METHODS

Specific IgE was evaluated in 10 individuals with an established molecular diagnosis of NS using an allergenic molecules microarray (immuno-solid-phase allergen chip).

RESULTS

Polireactivity to airway allergens, mainly house dust mites and olive tree pollen, and food allergens were observed in NS. Eighty per cent of patients were responsive to LTP or profilins. A clinical history suggestive of severe egg, milk, and fish allergy was confirmed by reactivity to the thermostable molecules Gal d 1, Bod 8, and parvalbumin Gad c 1, respectively. Latex reactivity was associated with Hev b 5 and 6 reactivity. Two distinct clusters of reactivity were observed after hierarchical analysis. Extremely high IgE levels (> 10,000 kU/L) do not affect the results obtained with microarrays.

CONCLUSION

IgE multiplex evaluation allows (i) to profile IgE polyreactivity pictures, in the presence of LTP and profilin sensitization, (ii) to verify the clinical history of food allergy to milk, egg, and seafood, (iii) to confirm the allergic events associated with latex exposure, and (iv) to disclose the presence of preclinical sensitizations in patients affected by primary immunodeficiencies with hyper IgE, such as the NS.

Mollusk allergy in shrimp-allergic patients: Still a complex diagnosis. An Italian real-life cross-sectional multicenter study

Introduction

Shellfish allergy is an important cause of food allergies worldwide. Both in vivo and in vitro diagnostics failure nowadays is caused by the poor quality of the extracts associated with the scarce availability of allergenic molecules in the market. It is known that not all patients with shellfish allergies experience adverse reactions to mollusks. It is still unclear how to detect and diagnose these patients correctly.

Aim

To investigate the features of shrimp-allergic patients either reactive or tolerant to mollusks, with the currently available diagnostic methods.

Methods

Nineteen centers, scattered throughout Italy, participated in the real-life study, enrolling patients allergic to shrimp with or without associated reactions to mollusks. Patients underwent skin tests using commercial extracts or fresh raw and cooked shrimp and mollusks, and IgE reactivity to currently available allergenic extracts and molecules was measured in vitro.

Results

Two hundred and forty-seven individuals with a self reported adverse reactions to shrimp participated in the study; of these 47.8% reported an adverse reaction to mollusks ingestion (cephalopod and/or bivalve). Neither of the tests used, in vivo nor in vitro, was able to detect all selected patients. Accordingly, a great heterogeneity of results was observed: in vivo and in vitro tests agreed in 52% and 62% of cases. Skin tests were able to identify the mollusk reactors (p < 0.001), also using fresh cooked or raw food (p < 0.001). The reactivity profile of mollusk reactors was dominated by Pen m 1, over Pen m 2 and Pen m 4 compared to tolerant subjects, but 33% of patients were not detected by any of the available molecules. Overall, a higher frequency of IgE rectivity to shrimp was recorded in northern Italy, while mollusk reactivity was more frequent in the center-south.

Conclusion

The current diagnostic methods are inadequate to predict the cross-reactivity between crustaceans and mollusks. The detection of mollusks hypersensitivity should still rely on skin tests with fresh material. The exclusion of mollusks from shrimp allergic patients’ diets should occur when clinical history, available diagnostic instruments, and/or tolerance tests support such a decision.

1

Current diagnostic methods are inadequate to predict cross-reactivity between crustaceans and mollusks;

2.

The detection of mollusks hypersensitivity must still rely on skin tests with fresh material (and oral challenges where possible);

3.

Clinically, there is no need to exclude a priori mollusks from shrimp allergic patients' diets;

A qualitative and quantitative comparison of IgE antibody profiles with two multiplex platforms for component-resolved diagnostics in allergic patients

BACKGROUND

Clinically complex phenotypes require more and more sophisticated and comprehensive diagnostic approaches, able to discriminate genuine sensitizations from cross-reactivity. Interpretative complexity of multiplex diagnostic arrays has somewhat limited their diffusion. This study compares two currently available methods, namely ISAC^® test and ALEX2^® test.

METHODS

In total, 140 allergic individuals, with a history of atopic dermatitis, adverse food reactions, allergic rhinitis and/or bronchial asthma were studied by Allergy Explorer-ALEX2^® macroarray and ImmunoCAP ISAC112^® . Lin's concordance correlation coefficient, intraclass correlation coefficient and Bland-Altman plots were used to verify the agreement between continuous values. Cohen's kappa coefficient (k) was assessed for the molecules available in both tests. The degree of relationship was analysed using Spearman's correlation (quantitative variables) and Pearson's χ² or Fisher's exact test (categorical variables).

RESULTS

A substantial agreement (κ = 0.795) was observed between the two methods with 94,3% concordant results when results were dichotomized as negative or positive, but if double-negative results were discarded, the agreement dropped to 71%. Conversely, little or no concordance was observed comparing raw data. Considering the 102 molecules shared by both systems, 28/102 (27%) showed an almost perfect agreement (k > 0.81), and concordance was good (k > 0.61) in a further 32 (31%) cases. A perfect to substantial agreement was observed by comparing species-specific aeroallergens. Heterogeneous results emerged comparing panallergens (co-recognition ranging from 30% for tropomyosin/serum albumins to 70% for PR-10/profilin). The correlation among LTP, profilin and PR-10 assayed with ISAC^® was better than ALEX2^® , but the latter identified more positive cases due to the wider number of molecules available. The CCD blocker provided by ALEX^® test abolishes the carbohydrate determinants signal in 60% of the 33 cases reactive to MUXF3 on the ISAC^® test.

CONCLUSION

Despite the excellent concordance of the species-specific markers, the analysis of the panallergens provided in both methods suggests a better performance of the ISAC^® test on those components, while the ALEX2^® test, which includes a larger number of allergens, allowing a broader molecular detection.

Abstract 3912: The PI3K/mTOR dual inhibitor PF-04691502 shows antitumor activity in Sezary cells and in a xenograft mouse model

Introduction: Cutaneous T-cell Lymphomas (CTCLs) are extranodal non-Hodgkin’s lymphomas deriving from neoplastic transformation of T lymphocytes that home to the skin. Mycosis fungoides (MF) is the most diffuse form, usually having an indolent course but presenting in some cases as an aggressive disease with a poor prognosis. Sézary syndrome (SS) is a rare and aggressive variant, with erythroderma, leukemia, and lymph node involvement. Despite recent advances, CTCLs are still incurable cancers and the clinical symptoms are highly disabling. Among the landscape of genomic alterations identified in CTCL, we and others have described alterations of the PI3K pathway members (loss of PTEN, LKB1 and PDCD4, and gain of p70S6K). As a consequence, several SS patients show hyper-activation of PI3K/AKT/mTOR pathway. Hence, inhibition of this pathway represents a potential therapeutic choice against CTCL.

Objective: In this work, we investigated the therapeutic potential of the dual-PI3K/mTOR inhibitor PF-04691502 (hereafter PF-502) against CTCL.

Materials and Methods: PF-502 therapeutic efficacy was evaluated in four CTCL cell lines and in patient-derived SS cells, for its ability to inhibit cell growth, to induce apoptosis and to inhibit chemotaxis toward the chemokine SDF-1. Moreover, to evaluate PF-502 therapeutic effects in vivo we used a xenograft mouse model, consisting of nude mice transplanted with the CTCL-derived HH cell line.

Results: PF-502 inhibited the cell growth of all the CTCL cell lines (0.07-0.32 µM, IC50 range), and of tumor cells derived from six SS patients (2.3 µM, mean IC50). The mechanism of action of PF-502 in CTCL cell lines was a combination of apoptosis induction and G1 block, while in SS patients it was mostly based on a strong apoptosis induction. Of note, PF-502 showed an only modest effect in T-lymphocytes from 3 healthy donors. PF-502 inhibited also cell migration toward the chemokine SDF-1, in both the systems. This result might have an important clinical implication because we have recently demonstrated that malignant lymphocytes are activated by the skin microenvironment. Thus, blocking the homing to the skin could affect the disease course. Finally, PF-502 has a robust antitumor activity in the xenograft mouse model, by reducing tumor volume (400 mm3 in treated mice vs 936 mm3 in controls) as well as tumor weight (0.2 g in treated mice vs 0.56 g in controls). Moreover, the Kaplan-Meier curve, in these mice, revealed that PF-502 treatment prolongs survival (P&lt;0.005).

Conclusions: Our results strongly support the therapeutic potential of targeting PI3K/AKT/mTOR pathway in CTCL.

Citation Format: Antonella Bresin, Cristina Cristofoletti, Francesca Monzo, Elisabetta Caprini, Mauro Helmer Citterich, Alessandra Frezzolini, Alessandro Monopoli, Roberto Benucci, Maria Cantonetti, Enrico Scala, Giandomenico Russo, Maria Grazia Narducci. The PI3K/mTOR dual inhibitor PF-04691502 shows antitumor activity in Sezary cells and in a xenograft mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3912.

Loss of β-arrestin-2 gene and possible functional consequences on Sezary Syndrome

Sezary Syndrome is an aggressive T-cell Lymphoma involving blood, skin and lymphonodes Involvement of the CXCR4-SDF1 has been previously shown. We here present evidence also of the involvement of B-arrestin a downstream regulator of CXCR4, that is depleted and downregulated as well as a potential functional role for this depletion.

Abstract 761: The role of PI3 kinase pathway in the the skin of Sezary syndrome

Sezary Syndrome (SS) is an aggressive variant of cutaneous T cell lymphoma (CTCL) characterized by an accumulation of malignant T lymphocytes - the Sezary (SS) cells - in the skin, lymph nodes and blood. Until now, most studies on the characterization of this lymphoma have been performed on circulating SS cells because of the easy availability of tumor material from this compartment. For this reason, the role of skin microenvironment has not been characterized although it might play a fundamental role in the pathogenesis and in the disease progression of this neoplasia. According to this view, we recently demonstrated that PTEN downregulation, due to genetic loss and microRNA deregulation, commonly observed in SS patients, mainly activates AKT in skin-resident respect to blood-derived SS cells. This data underline how microenvironment signals amplify genetic abnormalities. Based on these observations, we investigated the effect of the skin microenvironment on SS cells in vivo. Comparing skin and blood-derived SS cells concurrently obtained from SS patients, we demonstrate that skin milieu promotes proliferation and PI3K/AKT/mTORC1 activation, a pathway that we prove to have multiple copy number (CN) alterations in our cohort of forty-three patients, thus indicating these genetic lesions as valid therapeutic targets to treat SS. At the end, we also demonstrate that the progressive increase of these CN alterations is associated to the shortening of overall survival of SS patients.

Citation Format: Cristina Cristofoletti, Antonella Bresin, Mario Picozza, Maria Cristina Picchio, Francesca Passarelli, Francesca Monzo, Mauro Helmer Citterich, Alessandro Monopoli, Roberto Benucci, Maria Cantonetti, Alessandra Frezzolini, Enrico Scala, Elisabetta Caprini, Giandomenico Russo, Maria Grazia Narducci. The role of PI3 kinase pathway in the the skin of Sezary syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 761.

Abstract 936: Skin microenvironment enhances proliferation index and activates mTORC 1 signaling in sezary syndrome

Introduction

Sézary Syndrome (SS) is a rare and aggressive variant of Cutaneous-T-Cell Lymphoma (CTCL) characterized by the presence of malignant lymphocytes named Sezary (SS) cells in the skin, lymph nodes, and peripheral blood. With a poor prognosis, SS has not a specific therapy still available. As a role of skin in SS pathogenesis is not elucidated yet, here we study the contribution of this microenvironment by comparing matched skin and blood derived SS cells for tumor cell proliferation and activation levels of PI3k/AKT pathway. Using our previous SNP array data we also verified the genomic status of members belonging to this pathway in a large cohort of SS patients.

Methods

Expression of Ki67 proliferation marker was evaluated in perfect-paired blood and skin-paraffin biopsies

obtained from eleven SS patients by flow cytometry analysis and immunohistochemistry respectively. KI67+ neoplastic cells were calculated as percentage within neoplastic CD4+ cells recognized by a co-staining with the specific TCRVb rearrangement.

Phosphorylation levels of members of PI3k/AKT pathway were compared between matched circulating and skin resident SS cells proteins derived from 2 SS patients using an AKT kinase array (Cell Signaling). Affymetrix SNP6.0 arrays was used to investigate the copy number (CN) status of members of mTORC 1 pathway in a cohort in 37 SS samples derived from 23 SS patients and 3 cell lines.

Results

Skin derived SS cells showed a significant higher proliferation index (PI) respect to SS cells obtained from blood (12%±11 vs 1,24%+1,18; P = 0,00025). In order to identify the signals responsible for SS proliferation, we used a PI3K/AKT kinase array that revealed an enhanced phosphorylation levels of many components of this cascade, particularly of PRAS40 with a Fold change (Fc) of 6,15; GSK3a (Fc = 4.83), mTOR (Fc = 4.61) mP70S6K (Fc = 4.64) BAD (Fc = 7.09) and 4EBP1 (Fc = 5.40)in skin-SS cells respect to circulating ones.

We next deepen our observations in mTORC1 signaling because of this and earlier observations made in CTCL cell lines. Using our SNP6 array data we have verified the genomic status of members of this pathway. Results obtained showed that P70S6K, the kinase downstream TORC1 that plays a crucial role in protein synthesis, showed a mono-allelic gain in 9 out 23 patients (39%) whereas PDCD4, a protein that inhibits protein translation displayed a mono-allelic loss in 10 of 23 individuals (43%). 4 of these patients showed a concomitant P70S6K gain and PDCD4 loss. Overall these genetic defects suggest that an abnormal protein synthesis can occur in these patients..

Conclusion:

Our data demonstrate that skin microenvironment enhances SS cell proliferation index and activates mTORC1 signaling, an unbalanced pathway that reveals novel potential therapeutic targets for Sezary Syndrome.

Citation Format: Cristina Cristofoletti, Mario Picozza, Antonella Bresin, Maria Cristina Picchio, Enrico Scala, Giuseppe A. Lombardo, Francesca Passarelli, Elisabetta Caprini, Giandomenico Russo, Maria Grazia Narducci. Skin microenvironment enhances proliferation index and activates mTORC 1 signaling in sezary syndrome. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 936.

Targeting the PI3K/AKT/mTOR pathway overcomes the stimulating effect of dabrafenib on the invasive behavior of melanoma cells with acquired resistance to the BRAF inhibitor

BRAF inhibitors (BRAFi) have proven clinical benefits in patients with BRAF-mutant melanoma. However, acquired resistance eventually arises. The effects of BRAFi on melanoma cell proliferation and survival have been extensively studied, and several mechanisms involved in acquired resistance to the growth suppressive activity of these drugs have been identified. Much less is known about the impact of BRAFi, and in particular of dabrafenib, on the invasive potential of melanoma cells. In the present study, the BRAF-mutant human melanoma cell line A375 and its dabrafenib-resistant subline A375R were analyzed for invasive capacity, expression of vascular endothelial growth factor receptor (VEGFR)-2, and secretion of VEGF-A and matrix metalloproteinase (MMP)-9, under basal conditions or in response to dabrafenib. The consequences of inhibiting the PI3K/AKT/mTOR pathway on A375R cell responses to dabrafenib were also evaluated. We found that A375R cells were more invasive and secreted higher levels of VEGF-A and MMP-9 as compared with A375 cells. Dabrafenib reduced invasiveness, VEGFR-2 expression and VEGF-A secretion in A375 cells, whereas it increased invasiveness, VEGF-A and MMP-9 release in A375R cells. In these latter cells, the stimulating effects of dabrafenib on the invasive capacity were markedly impaired by the anti-VEGF‑A antibody bevacizumab, or by AKT1 silencing. A375R cells were not cross-resistant to the PI3K/mTOR inhibitor GSK2126458A. Moreover, this inhibitor given in combination with dabrafenib efficiently counteracted the stimulating effects of the BRAFi on invasiveness and VEGF-A and MMP-9 secretion. Our data demonstrate that melanoma cells with acquired resistance to dabrafenib possess a more invasive phenotype which is further stimulated by exposure to the drug. Substantial evidence indicates that continuing BRAFi therapy beyond progression produces a clinical benefit. Our results suggest that after the development of resistance, a regimen combining BRAFi with bevacizumab or with inhibitors of the PI3K/AKT/mTOR pathway might be more effective than BRAFi monotherapy.

miR-181b as a therapeutic agent for chronic lymphocytic leukemia in the Eµ-TCL1 mouse model

The involvement of microRNAs (miRNAs) in chronic lymphocytic leukemia (CLL) pathogenesis suggests the possibility of anti-CLL therapeutic approaches based on miRNAs. Here, we used the Eµ-TCL1 transgenic mouse model, which reproduces leukemia with a similar course and distinct immunophenotype as human B-CLL, to test miR-181b as a therapeutic agent.In vitro enforced expression of miR-181b mimics induced significant apoptotic effects in human B-cell lines (RAJI, EHEB), as well as in mouse Eµ-TCL1 leukemic splenocytes. Molecular analyses revealed that miR-181b not only affected the expression of TCL1, Bcl2 and Mcl1 anti-apoptotic proteins, but also reduced the levels of Akt and phospho-Erk1/2. Notably, a siRNA anti-TCL1 could similarly down-modulate TCL1, but exhibited a reduced or absent activity in other relevant proteins, as well as a reduced effect on cell apoptosis and viability. In vivo studies demonstrated the capability of miR-181b to reduce leukemic cell expansion and to increase survival of treated mice.These data indicate that miR-181b exerts a broad range of actions, affecting proliferative, survival and apoptotic pathways, both in mice and human cells, and can potentially be used to reduce expansion of B-CLL leukemic cells.

Abstract 3974: A preclinical study for miR181b as therapeutic in Eu-TCL1FL-tg mouse model for CLL

Chronic lymphocytic leukemia (CLL) is a malignancy of B cells with immunophenotype of memory cells. Downstream pathways to BCR, like NFkB, AKT and ERK, and anti-apoptotic proteins such as Bcl2 and Mcl1, are thought to contribute to expansion and survival of the malignant cells. CLL patients show different clinical course: tumor clones having no V-gene mutations, many CD38+ or ZAP-70+ B cells, chromosome 11q deletion and high expression of TCL1, had an aggressive, usually fatal course, whereas patients with mutated clones, few CD38+ or ZAP-70+ B cells and low TCL1 expression, had an indolent course. Recent studies identified a microRNA signature associated with prognosis and progression in B-CLL. Particularly, miR181b is down-regulated in aggressive forms of CLL and its expression is inversely correlated to Tcl1 levels.

An increasing number of studies are considering microRNAs as potentially useful therapeutic agents. Given that MCL-1, BCL-2 and TCL1 are proved targets for miR181b, that Akt activation is enhanced by Tcl1 and a crosstalk between Akt and ERK or NFkB exists, we performed a preclinical evaluation of miR181b therapeutic efficacy in a mouse model of CLL, the Eu-TCL1 transgenic mouse, previously generated by us.

In vitro enforced expression of miR-181b mimics induced a significant apoptotic effect in human B-cell line EHEB, as well as in mouse Eμ-TCL1 leukemic splenocytes. Molecular analyses revealed that miR-181b not only affected the expression of Tcl1, Bcl2 and Mcl1 anti-apoptotic proteins, but also increased the expression level of the NFkB inhibitor protein IkB-alpha and reduced the phosphorylation levels of Akt and Erk1/2. Notably, an anti-TCL1 siRNA could similarly down-modulate Tcl1 but exhibited a reduced or absent activity on other relevant proteins, as well as a reduced effect on cell apoptosis and viability. In vivo studies indicated a significant capability of miR-181b in reducing leukemic cells expansion and increasing survival of treated mice. These data indicate that miR-181b exerts a broad range of actions, affecting proliferative, survival and apoptotic pathways, both in mice and human, and can potentially be employed to reduce expansion of B-CLL leukemic cells.

Citation Format: Antonella Bresin, Elisa Callegari, Lucilla D'Abundo, Caterina Cattani, Cristian Bassi, Barbara Zagatti, Maria Grazia Narducci, Elisabetta Caprini, Yuri Pekarsky, Carlo Maria Croce, Silvia Sabbioni, Massimo Negrini, Giandomenico Russo. A preclinical study for miR181b as therapeutic in Eu-TCL1FL-tg mouse model for CLL. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3974. doi:10.1158/1538-7445.AM2015-3974

Skewed T-cell receptor variable β repertoire and massive T-cell activation in idiopathic orofacial granulomatosis

Orofacial granulomatosis (OFG) is a clinicopathologic entity describing oral lesions with noncaseating granulomas including a spectrum of diseases such as the Melkersson-Rosenthal syndrome. The involvement of abnormal T-cell responses has been suggested in the pathogenesis of OFG although few and contrasting data are currently available on this issue. In a patient with OFG, we observed virtually complete CD4 and CD8 T-cell receptor (TCR) β-chain variable region (BV) repertoires at the lesion level and in circulation. However, oligoclonal profiles were found in CD4 and, to a greater extent, in CD8 subsets. These findings were seen in association with a massive peripheral T-cell activation, decreased naive T cells, reduced thymic output, altered cytokine production, and increased apoptosis. Our data, pointing to a random influx of T cells at the site of inflammation, argue against the hypothesis of a main allergen acting at the level of oral mucosa. The profound dysregulation of the peripheral T-cell compartment suggests that OFG should be regarded as a systemic disorder with localized manifestations.

Abstract 4178: Tcl1 enhances keratinocytes’ survival/proliferation by promoting erk and jnk/sap phosphorylation at the expense of p38 and by controlling c-fos expression through miR-29b and miR-181a-1

The Tcl1 oncogene has been initially isolated for its involvement in chromosomal translocations of T-prolymphocytic leukemias and overexpression in B chronic lymphocytic leukemia by enhancing AKT nuclear translocation and allowing the Ser-473 transphosphorylation. Tcl1, also, acts as AP-1 transcriptional inhibitor, by interacting with c-fos and c-jun. More recent works have associated Tcl1 to proliferation and self-renewal ability of ES cells under the direct activation of OCT3/4, Zfx, KLF5 transcription factors, being Tcl1 expressed in preimplantation embryos where it allows the progression beyond the 4-cells stage. We have recently shown that the Tcl1 oncogene is expressed in epidermis and defines secondary hair germ (transient-amplifying, TA) cells differentiation at catagen-telogen (the degenerative-resting phase of the hair follicle (HF)) transition, allowing the proliferation of TA cells in anagen (regenerative phase of the HF), giving the slow-cycling stem cells, the ability to incorporate BrdU. In fact, Tcl1 mutant (Tcl1-/-) affects stem-cell marker CD34 expression and BrdU incorporation in the bulge and TA cells, resulting in skin defects in adults with the onset of alopecia followed by skin wounding. Phenomena that are almost completely rescued by K14-TCL1 transgenic expression, in vivo. Since Tcl1 has a role in maintenance of a normal skin homeostasis in mice, involving both hair growth and epidermis, we used the approach of the expression chip analysis to unravel the pathways that are affected by loss of function and overexpression of Tcl1 in epidermal keratinocytes, by using Tcl1-/- and K14-TCL1;Tcl1-/- mice models. Our findings show that Tcl1 function involves the MAPK pathway, since Tcl1-/- shows increasing in p38MAPK phosphorylation linked to terminal differentiation/senescence/apoptosis of keratinocytes, while K14-driven overexpression shows increasing of p-Erk and p-Sapk/p-Jnk phosphorylations, linked to proliferation/commitment of keratinocytes. These signals flow through the MAPK cascade lead to altered AP1 factor function. In particular, the phosphorylation of AP-1 subunit c-Jun and c-fos transcriptional regulation and cellular localization result also affected.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4178. doi:1538-7445.AM2012-4178

Proteomics plus genomics approaches in primary immunodeficiency: the case of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is a rare syndrome due to a mutation in the forkhead box protein 3 gene (FOXP3) leading to an impaired regulatory T cell (T(reg) ) activity associated both with skewed T helper type 2 (Th2) response and autoreactive phenomena. The purpose of this study was to describe a combined proteomics and genomics approach to comprehensively evaluate clinical and immunological phenotypes of patients affected by IPEX. T cell receptor (TCR)-Vβ repertoire and peripheral blood lymphocytes phenotype from three brothers affected by IPEX were studied by flow cytometry. Specific immunoglobulin (Ig)E were evaluated by means of an allergenic molecules microarray [immuno solid-phase allergen chip (ISAC)]. Total RNA was extracted and hybridized to Affymetrix oligonucleotide arrays to obtain quantitative gene-expression levels. No FOXP3 protein was detectable within CD127(-) CD25(high) CD4(+) T cells from peripheral blood. A T cell-naive phenotype (CD62L(+) CD45R0(-)) associated with a reduction of both CD26 and CD7 expression and a TCR-Vβ 8 and 22 family expansions were found. B lymphocytes were mainly CD5(+) (B1) cells expressing a naive phenotype (tcl1(+) CD27(-)). The three IPEX patients had severe food allergy and specific IgE reactivity to cow's milk allergens, a hen's egg allergen and a wheat allergen. Gene expression profile analysis revealed a dysregulation associated mainly with Th1/Th2 pathways. The multiplexing evaluation reported in this study represents a comprehensive approach in the assessment of genetic conditions affecting the immune system such as the IPEX syndrome, paving the way for the development of diagnostic tools to improve the standard clinical and immunological profiling of the disease.

MicroRNA profiling reveals that miR-21, miR486 and miR-214 are upregulated and involved in cell survival in Sézary syndrome

Sézary syndrome (SS) is an incurable leukemic variant of cutaneous T-cell lymphoma and its pathogenesis is still unknown. Diagnosis/prognosis may strongly ameliorate the management of SS individuals. Here, we profiled the expression of 470 microRNAs (miRNAs) in a cohort of 22 SS patients, and we identified 45 miRNAs differentially expressed between SS and controls. Using predictive analysis, a list of 19 miRNAs, including miR-21, miR-214, miR-486, miR-18a, miR-342, miR-31 and let-7 members were also found. Moreover, we defined a signature of 14 miRNAs including again miR-21, potentially able to discriminate patients with unfavorable and favorable outcome. We validated our data for miR-21, miR-214 and miR-486 by qRT-PCR, including an additional set of array-independent SS cases. In addition, we also provide an in vitro evidence for a contribution of miR-214, miR-486 and miR-21 to apoptotic resistance of CTCL cell line.

The role of 9-O-acetylated ganglioside D3 (CD60) and {alpha}4{beta}1 (CD49d) expression in predicting the survival of patients with Sezary syndrome

BACKGROUND

Sézary syndrome is a rare and very aggressive leukemic variant of cutaneous T-cell lymphoma characterized by extensive skin involvement and a malignant circulating CD4(+) T-cell clone which homes to the skin, over-expresses CD60, and lacks CD7, CD26 and CD49d. So far prognostic markers in this disease are limited to treatment with systemic steroids, age, serum lactate dehydrogenase, and a white blood cell count of 20×10(9)/L or higher: no other biological marker with prognostic value, especially related to malignant cells, has been described.

DESIGN AND METHODS

We used flow activated cell sorting analysis to compare the distribution of the T-cell receptor-Vβ repertoire and several surface molecules (CD7, CD26, CD49d and CD60) within the circulating CD4(+) T-cell population in 62 patients with Sézary syndrome, 180 with mycosis fungoides, 6 with B-cell lymphomas, and 19 with chronic eczema. We calculated the 5-year overall survival of patients with Sézary syndrome after first hospital admission using Kaplan-Meier product-limit estimates and hazard ratios from the Cox proportional hazards model.

RESULTS

We found that both higher number of CD60(+) and lower number of CD49d(+) cells within circulating CD4(+) T cells at disease presentation were significantly associated with a lower probability of survival. An exceedingly high risk of death was observed for patients with a combination of a high proportion of CD4(+)CD60(+) cells (≥ 0.5×10(9)/L) and low proportion of CD4(+)CD49d(+) cells (<0.5×10(9)/L) (hazard ratio = 12.303, 95% confidence interval 1.5-95.9; P<0.02). In addition, a skewed usage of T-cell receptor-Vβ subfamilies was observed in the circulating T-cell clone for 61.9% of all patients with Sézary syndrome, T-cell receptor-Vβ 2 and 5.1 subfamilies being the most frequently represented (42.8%), followed by T-cell receptor-Vβ 12 and 13.1.

CONCLUSIONS

In this study we showed that up-regulation of CD60 and down-regulation of CD49d on circulating CD4(+) T cells are two useful markers for predicting a very poor outcome in patients with Sézary syndrome.

Abstract 1736: Skewed usage of TCRVbeta repertoire and predictive role of CD60 and CD49d expression in the survival rate of patients with Sézàry Syndrome

Background: Sézary Syndrome (SS) is a rare and aggressive leukemic variant of Cutaneous T-Cell Lymphoma (CTCL) characterised by erythroderma and the presence of a malignant circulating memory CD4+ T cell clone with skin homing characteristics, lack of CD26 and CD49d and over-expression of CD60. The availability of a large panel of monoclonal antibodies to CDR3 Vß epitopes, allows the study of the TCR repertoire by flow cytometry and a more precise identification of the malignant clone phenotypic characteristics.

Objective: The aim of this study was to evaluate both the distribution of TCR-Vß family and CD60/CD49d expression within the clonal T cell population in patients affected by SS.

Methods: We studied, by five-color flow cytometry analysis, TCR-Vß repertoire in 62 patients affected by SS, in 180 patients with MF, 6 cases of B cell Lymphomas (BCL), 19 with chronic Eczema (CE) recruited and followed from 1998 to 2008. A sequential gating strategy was used in order to examine the CD60 and CR49d expression within the neoplastic clonal population identified through the TCR-Vß repertoire analysis.

Results and Conclusion: A skewed usage of only 4 out of 25 TCR-Vß subfamilies was observed in circulating T cell clone in 61.9% of patients affected by SS. TCR-Vß 2 and 5.1 were the most frequently represented (42.8% of TCR-Vß reactive patients), followed by TCR-Vß 12 and 13.1. In 20 cases the TCR-Vß panel was unable to identify the neoplastic clone, recognizing less than 5% of T cells, thus representing an indirect proof for the presence of a clonal population. CD60 was over expressed and CD49d down regulated within clonal T lymphocytes. This phenotype of the dominant T cell clone in the peripheral blood of patients with SS was significantly associated with a lower survival rate (chi-square 5.467, p &lt;0.019).

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1736.

CXCL13 is highly produced by Sézary cells and enhances their migratory ability via a synergistic mechanism involving CCL19 and CCL21 chemokines

Chemokine and chemokine receptors expressed by normal and neoplastic lymphocytes play a key role in cell recruitment into skin and lymph nodes. The aim of this study was to get further insights into the role of chemokines in pathogenesis and progression of cutaneous T-cell lymphoma (CTCL) with particular regard to Sézary Syndrome (SS), a CTCL variant with blood involvement. Here, we show that functional CXCL13 homeostatic chemokine is strongly up-regulated in SS cells, well-detectable in skin lesions and lymph nodes, and measurable at high concentration in plasma of SS patients, at different levels during disease progression. Furthermore, we show that the addition of CXCL13 to CCL19 or to CCL21, the selective CCR7 agonists responsible for lymph node homing, strongly enhances the migration of CCR7+ SS cells. We also show that neutralization of the CCR7 receptor strongly impairs CCL19/21-induced chemotaxis of SS cells both in the absence or presence of CXCL13. Additional experiments performed to investigate the survival, adhesion, and metalloproteases secretion indicate that CXCL13 combined with CCL19 and CCL21 mainly affects the chemotaxis of SS cells. Our findings suggest that this newly described CXCL13 expression in SS represents a new pathogenetic mechanism of diagnostic significance.

Skin homing of Sézary cells involves SDF-1-CXCR4 signaling and down-regulation of CD26/dipeptidylpeptidase IV

Sézary syndrome (SS) is a rare form of cutaneous T-cell lymphoma (CTCL) characterized by a distinct metastatic pattern mainly involving blood and skin. Chemokines and their receptors play a critical role in cellular recruitment and homing to tissues and in the metastatic process of several tumors including non-Hodgkin T-cell lymphomas (NHLs). Here we report that SS cells express a functionally active CXCR4 and that its ligand SDF-1 is abundantly produced in the skin, which represents the main destination of SS cell spreading. SDF-1 is normally inactivated by proteolytic cleavage by the CD26/dipeptidylpeptidase IV (DPPIV). The lack of CD26 from the cell surface is a hallmark of circulating SS cells. We also show that the CD26(-) phenotype is maintained also in skin-infiltrating neoplastic T lymphocytes and that SS-affected individuals exhibit a reduced activity of plasma soluble CD26. Finally, we observe that the addition of soluble CD26 reduces the migratory response of SS cells to SDF-1 whereas the inhibition of the CD26 peptidase activity in Hut78, a CD26(+) CTCL cell line, enhances the SDF-1-induced migration of these cells. Our findings suggest that the SDF-1-CXCR4 axis could play an important role in skin homing of SS through the regulatory activity of CD26.

Loss of RALT/MIG-6 expression in ERBB2-amplified breast carcinomas enhances ErbB-2 oncogenic potency and favors resistance to Herceptin

An emerging paradigm holds that loss of negative signalling to receptor tyrosine kinases (RTKs) is permissive for their oncogenic activity. Herein, we have addressed tumor suppression by RALT/MIG-6, a transcriptionally controlled feedback inhibitor of ErbB RTKs, in breast cancer cells. Knockdown of RALT expression by RNAi enhanced the EGF-dependent proliferation of normal breast epithelial cells, indicating that loss of RALT signalling in breast epithelium may represent an advantageous condition during ErbB-driven tumorigenesis. Although mutational inactivation of the RALT gene was not detected in human breast carcinomas, RALT mRNA and protein expression was strongly and selectively reduced in ERBB2-amplified breast cancer cell lines. Reconstitution of RALT expression in ERBB2-amplified SKBr-3 and BT474 cells inhibited ErbB-2-dependent mitogenic signalling and counteracted the ability of ErbB ligands to promote resistance to the ErbB-2-targeting drug Herceptin. Thus, loss of RALT expression cooperates with ERBB2 gene amplification to drive full oncogenic signalling by the ErbB-2 receptor. Moreover, loss of RALT signalling may adversely affect tumor responses to ErbB-2-targeting agents.

Hepatitis C virus drives the unconstrained monoclonal expansion of VH1-69-expressing memory B cells in type II cryoglobulinemia: a model of infection-driven lymphomagenesis

Chronic hepatitis C virus infection causes B cell lymphoproliferative disorders that include type II mixed cryoglobulinemia and lymphoma. This virus drives the monoclonal expansion and, occasionally, the malignant transformation of B cells producing a polyreactive natural Ab commonly encoded by the V(H)1-69 variable gene. Owing to their property of producing natural Ab, these cells are reminiscent of murine B-1 and marginal zone B cells. We used anti-Id Abs to track the stages of differentiation and clonal expansion of V(H)1-69(+) cells in patients with type II mixed cryoglobulinemia. By immunophenotyping and cell size analysis, we could define three discrete stages of differentiation of V(H)1-69(+) B cells: naive (small, IgM(high)IgD(high)CD38(+)CD27(-)CD21(high)CD95(-)CD5(-)), "early memory" (medium-sized, IgM(high)IgD(low)CD38(-)CD27(+)CD21(low)CD95(+)CD5(+)), and "late memory" (large-sized, IgM(low)IgD(low-neg)CD38(-)CD27(low)CD21(low-neg)CD5(-)CD95(-)). The B cells expanded in cryoglobulinemia patients have a "memory" phenotype; this fact, together with the evidence for intraclonal variation, suggests that antigenic stimulation by hepatitis C virus causes the unconstrained expansion of activated V(H)1-69(+) B cells. In some cases, these cells replace the entire pool of circulating B cells, although the absolute B cell number remains within normal limits. Absolute monoclonal V(H)1-69(+) B lymphocytosis was seen in three patients with cryoglobulinemia and splenic lymphoma; in two of these patients, expanded cells carried trisomy 3q. The data presented here indicate that the hepatitis C virus-driven clonal expansion of memory B cells producing a V(H)1-69(+) natural Ab escapes control mechanisms and subverts B cell homeostasis. Genetic alterations may provide a further growth advantage leading to an overt lymphoproliferative disorder.

Impaired T- and B-cell development in Tcl1-deficient mice

TCL1, the overexpression of which may result in T-cell leukemia, is normally expressed in early embryonic tissues, the ovary, and lymphoid lineage cells. Our analysis of mouse B-lineage cells indicates that Tcl1 expression is initiated in pro-B cells and persists in splenic marginal zone and follicular B cells. T-lineage Tcl1 expression begins in thymocyte progenitors, continues in CD4(+)CD8(+) thymocytes, and is extinguished in mature T cells. In Tcl1-deficient mice, we found B lymphopoiesis to be compromised at the pre-B cell stage and T-cell lymphopoiesis to be impaired at the CD4(+)CD8(+) thymocyte stage. A corresponding increase was observed in thymocyte susceptibility to anti-CD3epsilon-induced apoptosis. Reduced numbers of splenic follicular and germinal center B cells were accompanied by impaired production of immunoglobulin G1 (IgG1) and IgG2b antibodies in response to a T-dependent antigen. The marginal zone B cells and T-cell-independent antibody responses were also diminished in Tcl1(-/-) mice. This analysis indicates a significant role for Tcl1, a coactivator of Akt signaling, in normal T- and B-cell development and function.

Persistently Biased T-Cell Receptor Repertoires in HIV-1-Infected Combination Antiretroviral Therapy???Treated Patients Despite Sustained Suppression of Viral Replication

In most HIV-1-infected patients, highly active antiretroviral therapy (HAART) reduces plasma viral load to <50 copies/mL and increases CD4+ T-cell number and function. However, it is still unclear whether alterations of T-cell receptor (TCR) beta-chain variable region (BV) repertoire, tightly related to disease progression, can be fully recovered by long-term treatment with HAART. This study analyzed the evolution of both T-cell subset composition and TCRBV perturbations in chronically HIV-1-infected patients with moderate immunodeficiency during 36 months of HAART. Despite persistently suppressed HIV replication, the rate of CD4+ T-cell repopulation, after an initial burst, progressively declined throughout the study period, resulting in a mean CD4+ T-cell count at the end of follow-up that was still significantly lower in HIV patients than in HIV-seronegative controls. This was seen in association with an incomplete restitution of both CD4 and CD8 TCRBV repertoire disruptions and was also demonstrated by the appearance of new TCRBV oligoclonal expansions occurring during HAART. In conclusion, these data indicate that 3 years of fully suppressive HAART may be not adequate to normalize CD4 counts and TCRBV repertoires in patients starting HAART with moderately advanced disease.

Biased T-cell receptor repertoires in patients with chromosome 22q11.2 deletion syndrome (DiGeorge syndrome/velocardiofacial syndrome)

Chromosome 22q11.2 deletion (del22q11.2) syndrome (DiGeorge syndrome/velocardiofacial syndrome) is a common syndrome typically consisting of congenital heart disease, hypoparathyroidism, developmental delay and immunodeficiency. Although a broad range of immunologic defects have been described in these patients, limited information is currently available on the diversity of the T-cell receptor (TCR) variable beta (BV) chain repertoire. The TCRBV repertoires of nine patients with del22q11.2 syndrome were determined by flow cytometry, fragment size analysis of the third complementarity determining region (CDR3 spectratyping) and sequencing of V(D)J regions. The rate of thymic output and the phenotype and function of peripheral T cells were also studied. Expanded TCRBV families were detected by flow cytometry in both CD4+ and CD8+ T cells. A decreased diversity of TCR repertoires was also demonstrated by CDR3 spectratyping, showing altered CDR3 profiles in the majority of TCRBV families investigated. The oligoclonal nature of abnormal peaks detected by CDR3 spectratyping was confirmed by the sequence analysis of the V(D)J regions. Thymic output, evaluated by measuring TCR rearrangement excision circles (TRECs), was significantly decreased in comparison with age-matched controls. Finally, a significant up-regulation in the percentage, but not in the absolute count, of activated CD4+ T cells (CD95+, CCR5+, HLA-DR+), IFN-gamma - and IL-2-expressing T cells was detected. These findings suggest that the diversity of CD4 and CD8 TCRBV repertoires is decreased in patients with del22q11.2 syndrome, possibly as a result of either impaired thymic function and/or increased T-cell activation.

Skewed T-cell receptor repertoire, decreased thymic output, and predominance of terminally differentiated T cells in ataxia telangiectasia

Ataxia telangiectasia (A-T), a genetic disorder caused by the homozygous mutation of the ATM gene, frequently associates with variable degrees of cellular and humoral immunodeficiency. However, the immune defects occurring in patients with A-T are still poorly characterized. Here we show that the T-cell receptor (TCR) variable beta (BV)-chain repertoire of 9 A-T patients was restricted by diffuse expansions of some variable genes prevalently occurring within the CD4 subset and clustering to certain TCRBV genes (eg, 5.1, 11, 14, and 23). In addition, the study of the third complementarity-determining region (CDR3) showed, in all patients, significantly altered profiles in most BV genes examined suggesting diffuse oligoclonal expansions. The sequencing of TCR CDR3 regions revealed completely normal V(D)J coding joints and confirmed a reduced diversity of the antigen-receptor repertoire. The B-cell repertoire was similarly restricted and skewed by diffuse oligoclonal expansions with normal V(D)J joints. Thymic output, evaluated by measuring TCR rearrangement excision circles, was extremely low. The majority of peripheral T cells had the phenotype and the function of effector memory cells, indicating that in vivo they are able to respond normally by terminal differentiation to antigenic stimulation. These results indicate that ATM mutation limits the generation of a wide repertoire of normally functioning T and B cells.

Low frequency of alterations of the alpha (PPP2R1A) and beta (PPP2R1B) isoforms of the subunit A of the serine-threonine phosphatase 2A in human neoplasms

The phosphatase 2A (PP2A) is one of the major cellular serine-threonine phosphatases. It was recently shown that the gene encoding for the beta isoform of its subunit A, PPP2R1B, is altered in human lung and colorectal carcinomas, suggesting a role in human tumorigenesis. Here, we report the detection of mutations in breast, lung carcinomas and melanomas in the genes of both alpha (PPP2R1A) and beta isoforms. Mutations affecting PPP2R1B were found in four breast carcinomas, while mutations in PPP2R1A were found in carcinomas of the breast and of the lung and in one melanoma. Most of the mutations affecting PPP2R1B were exons deletions, suggesting abnormal splicing. These splicing abnormalities were detected in tumor samples in the absence of the normal splicing product, and were not found in several normal controls. In one case, a homozygous deletion present in tumor DNA, and not in the matched normal control was demonstrated. Mutations affecting the PPP2R1A gene were nucleotide substitutions changing highly conserved amino acids and one frame-shift. Although the frequency of alterations is low, the inclusion of both isoforms of subunit A in the genes mutated in human cancer and the addition of breast cancer to the list of neoplasms in which PPP2R1B is altered, strengthen the potential role of PP2A in human tumorogenesis.

Molecular cloning and characterization of ZNF202: a new gene at 11q23.3 encoding testis-specific zinc finger proteins

Two distinct regions of loss of heterozygosity (LOH) in breast carcinomas were previously identified at chromosome 11q23. With the aim of identifying a tumor suppressor gene, we undertook the isolation and characterization of genes within LOH region 2, defined between loci D11S1345 and D11S1316, which spans an area of about 1 Mb. Here, we describe the cloning and characterization of a new gene, ZNF202. The gene, which spans a genomic area of approximately 10 kb, is almost exclusively expressed in testis as a 4-kb mRNA. The predicted amino acid sequence of the protein product revealed significant homologies with zinc finger proteins, indicating that the ANF202 protein may function as a transcription factor. The presence of multiple CK2 and PKC phosphorylation sites suggests that its activity may be regulated by phosphorylation. The gene is also expressed in breast carcinoma cell lines. However, mutation analysis of 39 breast cancer samples revealed no evidence of mutations, indicating that ZNF202 is unlikely to be involved in the pathogenesis of this neoplasm. Nevertheless, a role for ZNF202 in the tumorigenic process of other tissues cannot be excluded.

Translation and ribosome assembly in extremely thermophilic archaebacteria

Several features of translation and ribosome structure in extremely thermophilic, sulfur-dependent archaebacteria are described, including: i) a peculiar mechanism of transfer RNA-mediated 70S ribosome formation from free subunits; ii) poly(U)translation by hybrid ribosomes composed by one archaebacterial and one eucaryotic subunit; iii) ribosome assembly and homologous and heterologous RNA/protein recognition.

Early assembly proteins of the large ribosomal subunit of the thermophilic archaebacterium Sulfolobus. Identification and binding to heterologous rRNA species

Studies of ribosome structure in thermophilic archaebacteria may provide valuable information on (i) the mechanisms involved in the stabilization of nucleic acid-protein complexes at high temperatures and (ii) the degree of evolutionary conservation of the ribosomal components in the primary kingdoms of cell descent. In this work we investigate certain aspects of RNA/protein interaction within the large ribosomal subunits of the extremely thermophilic archaebacterium Sulfolobus solfataricus. The ribosomal proteins involved in the early reactions leading to in vitro particle assembly have been identified; it is shown that they can interact with the RNA in a temperature-independent fashion, forming a thermally stable "core" particle that can subsequently be converted into complete 50 S ribosomes. Among the protein components of the core particle, those capable of independently binding to 23 and 5 S RNA species have also been identified. Finally, we show that the early assembly proteins of Sulfolobus large ribosomal subunits are able to interact cooperatively with 23 S RNAs from other archaebacteria or from eubacteria, thereby suggesting that RNA/protein recognition sites are largely conserved within prokaryotic ribosomes. By contrast, no specific binding of the archaebacterial proteins to eukaryotic RNA could be demonstrated.