Abstract: The management of unresectable metastatic melanoma is a major clinical challenge because of the lack of reliably effective systemic therapies. Blocking cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) has recently been proposed as a strategy to enhance cell-mediated immune responses to cancer, and clinical trials have demonstrated that anti-CTLA-4 therapy can produce durable outcomes with different response patterns than cytotoxic chemotherapy. We enrolled eight out of 155 patients with advanced melanoma in a multicentre phase II trial that evaluated the activity and tolerability of ipilimumab, a fully human, anti-CTLA-4 monoclonal antibody ( www.clinicaltrials.gov ; NCT00289627; CA184-008). Here we report our experience with three of these patients, who experienced progressive disease after a variety of previous therapies, including prior immunotherapies, and who achieved good outcomes with ipilimumab. One patient had a partial response ongoing at 17+ months on ipilimumab despite failure with four prior therapies, and the other two patients showed durable stable disease, both still ongoing at 17+ and 20+ months, respectively. The patient achieving a partial response experienced no side effects while receiving ipilimumab. The other two patients developed immune-related adverse events (irAEs) including rash (one case; grade 2) and diarrhoea (both cases; grades 1 and 2, respectively); the histopathology of colon biopsy samples from both was suggestive of colitis, with an abundant CD8+ T-cell infiltrate. Nausea, vomiting and acute pancreatitis were also observed in one patient. In addition, immunohistochemical findings of a dense CD8+, TIA1+ and granzyme B+ lymphoid infiltrate within a biopsied lesion provide indirect evidence of functional T-cell activation induced by treatment. These case reports highlight the potential for anti-CTLA-4-based therapy in previously treated patients with advanced melanoma. Moreover, because the patterns of response to ipilimumab differ from chemotherapy, we need to understand how and when patients may respond to treatment so that appropriate clinical decisions can be made.
Abstract: The role of genetic factors involved in the development of undifferentiated nasopharyngeal carcinoma (UNPC) in nonendemic areas has been poorly investigated. High-resolution human leukocyte antigen (HLA) class I genotyping carried out in 82 Italian UNPC patients and 286 bone marrow donors born in the same province showed that A*0201, B*1801, and B*3501, known to efficiently present Epstein-Barr virus (EBV)-derived epitopes, were significantly under-represented in UNPC patients. Moreover, the A*0201/B*1801 haplotype was significantly less frequent in UNPC cases, with a 90\% reduced risk (odds ratio [OR] 0.1, 95\% confidence interval [CI] = 0.0-0.5) to develop UNPC, suggesting an additive effect. Notably, all 5 BARF1 epitopes and 7 of the 8 LMP-2 epitopes known to bind A*0201 showed a fully conserved sequence in all the 31 Italian EBV isolates investigated. The 4 amino acid changes affecting the 436-447 LMP-2 epitope do not reduce, but rather increase in two cases, the predicted ability of "variant" epitopes to bind the HLA-A*0201 allele, as shown by immunoinformatic analysis. Moreover, a significantly increased risk for UNPC was associated with A*2601 (OR 2.4, 95\% CI = 1.1-4.9) and B*4101 (OR 9.2, 95\% CI = 2.5-34.3). These findings indicate that Italian UNPC patients have a distinct HLA-A and -B genotypic profile and suggest that the decreased risk for UNPC conferred by definite HLA class I molecules is probably related to their ability to efficiently present LMP-2 and BARF1 epitopes that are highly conserved in EBV isolates from this geographic region. These results have practical implications for the immunotherapy of UNPC.
Abstract: Functional characterization of signaling pathways that critically control mantle cell lymphoma (MCL) cell growth and survival is relevant to designing new therapies for this lymphoma. We herein demonstrate that the constitutive activation of Akt correlates with the expression of the phosphorylated, inactive form of PTEN. Phosphatidyl-inositol-3 kinase (PI3-K)/Akt or mammalian target of rapamycin (mTOR) inhibition decreased the growth of both primary MCL cultures and established cell lines and antagonizes the growth-promoting activity of CD40 triggering and IL-4. These effects are mediated by nuclear accumulation of the p27(Kip1) inhibitor induced by down-regulation of the p45(Skp2) and Cks1 proteins, which target p27(Kip1) for degradation. Moreover, Akt inhibition down-regulated cyclin D1 by promoting its proteasome-dependent degradation driven by GSK-3. Intriguingly, mTOR inhibition affected cyclin D1 proteolysis only in MCL cells in which GSK-3 is under the direct control of mTOR, suggesting that different MCL subsets could be differently responsive to mTOR inhibition. Finally, PI3-K/Akt inhibitors, but not rapamycin, induced variable levels of caspase-dependent apoptosis and reduced telomerase activity. These results indicate that Akt and mTOR activation have distinct functional relevance in MCL and suggest that targeting Akt may result in more effective therapeutic effects compared with mTOR inhibition.
Abstract: BACKGROUND: Retinoids have a pronounced antiviral effect against several viruses. In this study we aimed to investigate the effect of retinoids on human herpesvirus 8 (HHV-8). METHODS: A panel of retinoic acid compounds were tested for their antiviral activity against HHV-8 in human umbilical vascular endothelial cells (HUVECs) and in a human epithelial cell line. The presence, transcription and antigen expression of HHV-8 in infected cells - in the presence or absence of retinoic acid compounds - were evaluated by PCR, reverse transcriptase PCR and immunofluorescence assays; HHV-8 viral load was determined by real-time quantitative PCR. Angiogenesis induced by HHV-8 was also assessed using Cultrex basement membrane extract. RESULTS: The compounds tested specifically inhibited viral promoters, during the early and late phases of infection in both cell systems tested, and resulted in up to 100-fold reduction of viral titre and release of progeny virus. The inhibition of viral replication induced by retinoids in endothelial cells, the primary target of HHV-8-driven transformation in Kaposi's Sarcoma, prevented endothelial cells from developing spindle morphology and in vitro tube formation, characteristic changes associated with HHV-8 infection and transformation. CONCLUSIONS: We show that retinoids inhibit HHV-8 replication and identify new retinoid compounds with a strong antiviral effect. Selective retinoids, particularly those with retinoic acid receptor agonist activity, may be good candidates for the development of antiviral drugs.
Abstract: PURPOSE: Chlamydia psittaci (Cp) has been associated to ocular adnexal lymphomas (OAL) with variable geographic distribution. Herein, we used multiple Chlamydia detection tools to identify Cp elementary bodies-containing cell and to assess Cp prevalence in both nodal and extranodal lymphomas. EXPERIMENTAL DESIGN: TETR-PCR, immunohistochemistry, immunofluorescence, electron microscopy, and laser-capture microdissection were done in 35 OALs to define their effect in Chlamydia detection and, moreover, to identify the Cp cellular carrier. Cp prevalence was screened by TETR-PCR in 205 extraorbital lymphomas and 135 nonneoplastic controls. RESULTS: Twenty-six (74\%) OALs were associated with Cp infection: immunohistochemistry, immunofluorescence, and laser-capture microdissection-assisted PCR showed that monocytes/macrophages were the Cp carriers; electron microscopy showed the presence of intact Cp elementary bodies into these cells. Immunohistochemistry and TETR-PCR showed a 70\% concordance rate (P = 0.001). Cp DNA was equally prevalent in non-OAL, nodal, and extranodal lymphomas: among the latter, it was more common in diffuse large B-cell lymphomas of the skin (P = 0.03) and Waldeyer's ring. CONCLUSIONS: This multiparametric approach shows, for the first time, that monocytes/macrophages are the carriers of Cp, Cp seems preferentially associated with lymphomas arising in organs primarily exposed to antigens. The clinical implications of these findings deserve to be prospectively investigated.
Abstract: BACKGROUND: Engagement of CD40 promotes survival of undifferentiated nasopharyngeal carcinoma (UNPC) cells and similar effects are induced by the EBV oncoprotein LMP-1 that is expressed in a fraction of cases. Considering that CD40 may be activated also by the soluble isoform of CD40L (sCD40L), we investigated the serum levels of sCD40L in a series of 61 UNPC patients from Italy, a non-endemic area for this disease. RESULTS: At diagnosis, serum samples of UNPC patients contained significantly higher levels of sCD40L than age-matched healthy controls (p < 0.001). High levels of sCD40L (i.e., >18 ng/ml) were more frequently found in patients <40 years of age (p = 0.03) and with distant metastases at presentation (p = 0.03). Serum levels of sCD40L were inversely associated with the expression of the EBV oncoprotein LMP-1 (p = 0.03), which mimics a constitutively activated CD40. The amount of sCD40L decreased in a fraction of patients treated with local radiotherapy alone. Moreover, CD40L+ lymphoid cells admixed to neoplastic UNPC cells were detected in cases with high serum levels of sCD40L, suggesting that sCD40L is probably produced within the tumor mass. CONCLUSION: sCD40L may contribute to CD40 activation in UNPC cells, particularly of LMP-1-negative cases, further supporting the crucial role of CD40 signalling in the pathogenesis of UNPC. sCD40L levels may be useful to identify UNPC patients with occult distant metastases at presentation.
Abstract: PURPOSE: To investigate the potential of the DNA hypomethylating agent 5-aza-2'-deoxycytidine (5-aza-CdR) to improve the effectiveness of immunotherapeutic approaches against melanocyte differentiation antigens. EXPERIMENTAL DESIGN: The effect of 5-aza-CdR on the constitutive expression of gp100 was investigated in 11 human melanoma cell lines by real-time reverse transcription-PCR and indirect immunofluorescence (IIF) analyses. 5-aza-CdR-mediated changes in the levels of expression of human leukocyte antigen (HLA) class I antigens and HLA-A2 allospecificity, intercellular adhesion molecule-1 (ICAM-1), and leukocyte-function-associated antigen-3 were investigated by IIF analysis on melanoma cells under study. The recognition of gp100-positive Mel 275 melanoma cells, treated or not with 5-aza-CdR, by HLA-A2-restricted gp100((209-217))-specific CTL was investigated by (51)Cr-release assays, IFN-gamma release and IFN-gamma ELISPOT assays. RESULTS: The constitutive expression of gp100 was not affected by 5-aza-CdR on all melanoma cells investigated. Compared with untreated cells, the exposure of Mel 275 melanoma cells to 5-aza-CdR significantly (P < 0.05) up-regulated their expression of HLA class I antigens and of ICAM-1. These phenotypic changes significantly (P < 0.05) increased the lysis of 5-aza-CdR-treated Mel 275 melanoma cells by gp100-specific CTL and increased their IFN-gamma release. 5-aza-CdR treatment of Mel 275 cells also induced a higher number of gp100-specific CTL to secrete IFN-gamma. CONCLUSIONS: Treatment with 5-aza-CdR improves the recognition of melanoma cells by gp100-specific CTL through the up-regulation of HLA class I antigens expression; ICAM-1 also contributes to this phenomenon. These findings highlight a broader range of therapeutic implications of 5-aza-CdR when used in association with active or adoptive immunotherapeutic approaches against a variety of melanoma-associated antigens.
Abstract: DNA methylation regulates gene expression in normal cells. This epigenetic mechanism acts in at least two different ways: at global genomic level by targeting repetitive sequences distributed among the whole genome (LINEs, SINEs, satellite DNA, transposons) and at local level by targeting CpG islands in promoter regions. Both epigenetic mechanisms are involved in the carcinogenetic process; however, different evidences suggest that promoter hypermethylation occurring in genes involved in cell-cycle regulation, DNA repair, cell signalling, transcription and apoptosis likely plays a prominent role. Opposite to genetic defects DNA hypermethylation is a reversible process that can be handled through "epigenetic drugs" in a wide spectrum of tumors. Along this line, recent data have demonstrated the ability of DNA hypomethylating agents to up-regulate and/or induce the expression of genes silenced by promoter hypermethylation in cancer. Particularly relevant seems the ability of these drugs to modulate the expression of genes coding for molecules crucial for tumor immunogenicity and immune recognition of neoplastic cells by host's immune system, such as Cancer Testis Antigens, HLA class I molecules, costimulatory molecules. These evidences, coupled to the well-known cytotoxic, pro-apoptotic, and differentiating activities of epigenetic drugs, encourage to design and to develop new therapeutic strategies able to circumvent the immune escape of neoplastic cells and to potentiate the efficacy of immunotherapy in cancer patients. This review will provide an update on the most recent information about aberrant DNA methylation in cancer and on innovative therapeutic strategies of "epigenetic remodelling" of human malignancies, with particular attention to the immunologic and immunotherapeutic potential of this approach.
Abstract: The ability of the immune system to distinguish between self and non-self is critical to the functioning of the immune response. A breakdown in these mechanisms can lead to the onset of autoimmune disease. Clinical and molecular data suggest that shared immunogenetic mechanisms lead to the autoimmune process. The most studied part of the autoimmune process is the human leukocyte antigen (HLA) region. Recently, progress has been made in narrowing down HLA cluster classifications based on structural and functional features of HLA alleles. Using this approach we have investigated 175 patients with hepatitis C virus (HCV)-induced type II cryoglobulinemia (MC), and compared them to a control group of 14,923 bone marrow donors. Additionally, we investigated the frequency of HLA homozygosity in the same groups of subjects. Our results provide evidence of a role for DR5 and DQ3 HLA class II clusters and a higher frequency of HLA homozygous leading to the clinical outcome of type II mixed cryoglobulinemic autoimmune disease. The DR5 cluster is characterized by a Glu in beta 9 and its polymorphism is connected with preferred anchors at beta 9 of the binding peptide, while the DQ3 cluster is characterized by Glu B86 and Leu B87, which allows the binding of large hydrophobic amino acids at p1 of the binding peptide. The mechanisms by which variations in HLA lead to autoimmunity remain unknown, although they are likely to be mediated by continuous presentation of HCV epitopes to T cells and a genetic background that limits the effective clearance of HCV. The results presented in this paper have increased our knowledge of the mechanism of autoimmune disease and B-cell lymphoproliferation during HCV infection. The work was performed in accordance with the principles of the 1983 Declaration of Helsinki. There is no conflict of interest.
Abstract: BACKGROUND: The prevalence and the clinical impact of gastric Helicobacter pylori (Hp) infection, as well as its possible correlation with Chlamydia psittaci (Cps) infection and the lymphoma regression rate produced by Hp eradicating antibiotic therapy were investigated in patients with MALT-type lymphoma of the ocular adnexa (OAL). METHODS: During staging, the presence of gastric Hp infection was assessed by gastroscopy and multiple biopsies in 31 OAL patients. Immediately after, Hp-positive patients were treated with eradicating antibiotic therapy, alone or associated with other therapies. RESULTS: Gastric Hp infection was detected in 10 (32\%) patients; this feature did not correlate with patients' characteristics and disease. Four Hp-positive patients were treated with Hp-eradicating antibiotics therapy as exclusive strategy (assessable for response), none of them showed lymphoma regression. Conversely, 6 Hp-positive patients were treated with antibiotic therapy concurrently with other therapies, achieving lymphoma regression in all cases. Three Hp-positive patients with Cps-positive lymphoma were treated with doxycycline at relapse, resulting in two CR and one PR, which lasted 24+, 20+, and 18+ months, respectively. One of these patients achieved a CR after doxycycline despite the chronic persistence of Hp infection, whereas Cps-eradication was confirmed in the analysis of PBMC samples. CONCLUSIONS: Gastric Hp infection, even if common among OAL patients, does not influence clinical presentation. Hp-eradicating antibiotic therapy is not active against OAL. Cps-eradicating antibiotic therapy with doxycycline induces lymphoma remission irrespectively of the persistence of Hp infection.
Abstract: PURPOSE: Cytokines such as IL-10 and IL-18 seem to be involved in the inflammatory response of undifferentiated carcinoma of nasopharyngeal type (UCNT). The aim of this study was to evaluate the correlation between functional single nucleotide polymorphisms (SNPs) in the promoter region of IL-10 and IL-18 genes and the virological and clinical characteristics in a large case series of Caucasian patients suffering from UCNT, a tumor regularly associated with the Epstein Barr Virus (EBV). METHODS: Eighty-nine patients with histologically confirmed UCNT and 130 healthy donors were included in our study. DNA was examined for the polymorphisms of IL-10 gene at positions -1082, -819, -592 by direct sequencing and IL-18 gene at position -607 and -137 by allele-specific PCR. EBV DNA serum viremia was evaluated by QC-PCR. RESULTS: The distributions of the IL-10 and IL-18 genetic variants were not different between UCNT patients and healthy controls. The frequency of IL-10 -1082G allele, which is associated with high IL-10 expression, showed a nearly statistically significant increase in UCNT patients EBV DNA-negative as compared to healthy controls (OR=3.3 95\% CI: 1.2-9.8). Subjects with C/C or C/G combined IL-18 genotypes showed an increased risk of being with Stages III-IV (OR=2.1 95\% CI: 1.2-6.6). CONCLUSION: This study was performed to improve the definition of the pathogenetic factors implicated in UCNT by addressing the correlation between cytokine polymorphisms and clinical parameters. This is the first study investigating the possible role of the IL-18 and IL-10 polymorphisms in the development and outcome of UCNT. In our genetic analysis there is no evidence for involvement of IL-10 promoter polymorphisms alone in the genetic predisposition to this tumor. On the other hand, IL18 genetic variants may represent a genetic risk factor for tumor aggressiveness.
Abstract: Mucosa-associated lymphoid tissue (MALT) lymphoma probably constitutes the best in vivo model showing how complex interplay between B lymphocytes and the surrounding microenvironment may lead to a neoplastic disorder. After the seminal discovery of the pathogenic association between Helicobacter pylori and gastric MALT lymphomas, evidence suggests the possible involvement of other infectious agents in the development of MALT lymphomas arising at different body sites. Although several other bacteria (Borrelia burgdorferi, Campylobacter jejuni, and Chlamydia psittaci) and viruses (Hepatitis C virus) seem to play a role in lymphomas presenting at different locations, a possible common pathogenic mechanism is emerging. Several lines of evidence suggest that different infectious agents might provide a chronic antigenic stimulation that elicits host immune responses able to promote clonal B-cell expansion. This model is also substantiated by the increasing number of patients with MALT lymphomas who exhibit objective clinical responses after antimicrobial therapy. A multidisciplinary approach is critical to better understand the complex etiopathogenesis of MALT lymphomas with the final goal to dissect the clinicopathologic heterogeneity of these disorders and design more tailored preventive and therapeutic approaches.
Abstract: BACKGROUND: A pathogenic link between hepatitis C virus (HCV) and MALT-type lymphomas has been suggested. However, studies assessing the role of HCV infection separately in different forms of MALT lymphomas are not available. PATIENTS AND METHODS: The prevalence and clinical implications of HCV seropositivity were analyzed in 55 patients with ocular adnexa lymphoma (OAL) of MALT-type. RESULTS: HCV seropositivity was detected in seven (13\%) patients. At presentation, HCV infection was significantly associated with concomitant extra-orbital disease, lymph node dissemination and involvement of additional extranodal organs. HCV seropositivity was associated also with a higher relapse rate and worse progression-free survival. In fact, 16 patients experienced relapse after first-line treatment: five (71\%) were HCV-seropositive and 11 (23\%) were HCV-seronegative, with a median TTP of 31 and 50+ months (P = 0.01), and a 5-year progression-free survival of 43 +/- 18\% and 77 +/- 7\% (P = 0.005), respectively. HCV-seropositive patients experienced frequent relapses despite further lines of therapy; relapses were systemic in all cases but one; multiple subcutaneous nodules were common at relapse. CONCLUSIONS: HCV seropositivity is present in 13\% of OAL of MALT-type. Concomitant HCV infection is associated with more disseminated disease and aggressive behavior in OAL, with a consequent potential negative impact in patients managed with radiotherapy alone.
Abstract: BACKGROUND: An association between ocular adnexal MALT lymphoma (OAL) and Chlamydia psittaci (Cp) infection has been proposed, and recent reports suggest that doxycycline treatment causes tumor regression in patients with Cp-related OAL. The effectiveness of doxycycline treatment in Cp-negative OAL has not been tested. METHODS: In a prospective trial, 27 OAL patients (15 newly diagnosed and 12 having experienced relapse) were given a 3-week course of doxycycline therapy. Objective lymphoma response was assessed by computerized tomography scans or magnetic resonance imaging at 1, 3, and 6 months after the conclusion of therapy and every 6 months during follow-up. Cp infection in patients was determined by touchdown enzyme time-release polymerase chain reaction (TETR-PCR). Statistical tests were two-sided. RESULTS: Eleven patients were Cp DNA-positive and 16 were Cp DNA negative. Doxycycline was well tolerated. At a median follow-up of 14 months, lymphoma regression was complete in six patients, and a partial response (> or = 50\% reduction of all measurable lesions) was observed in seven patients (overall response rate [complete and partial responses] = 48\%). Lymphoma regression was observed in both Cp DNA-positive patients (seven of 11 experienced regression) and Cp DNA-negative patients (six of 16 experienced regression) (64\% versus 38\%; P = .25, Fisher's exact test). The three patients with regional lymphadenopathies and three of the five patients with bilateral disease achieved objective response. In relapsed patients, response was observed both in previously irradiated and nonirradiated patients. The 2-year failure-free survival rate among the doxycycline-treated patients was 66\% (95\% confidence interval = 54 to 78), and 20 of the 27 patients were progression free. CONCLUSIONS: Doxycycline is a fast, safe, and active therapy for Cp DNA-positive OAL that was effective even in patients with multiple failures involving previously irradiated areas or regional lymphadenopathies. The responses observed in PCR-negative OAL may suggest a need for development of more sensitive methods for Cp detection and investigation of the potential role of other doxycycline-sensitive bacteria.
Abstract: Eight patients with ocular adnexal mucosal-associated lymphpid tissue (MALT) lymphoma were treated with rituximab, at diagnosis (n=5) or relapse (n=3). All untreated patients achieved lymphoma regression, while relapsing patients had no benefit. Four responding patients experienced early relapse. The median time to progression was 5 months. The efficacy of rituximab in ocular adnexal lymphoma is lower than that reported for gastric MALT lymphomas.
Abstract: PURPOSE: Some infectious agents contributing to lymphomagenesis have been considered targets for new therapeutic strategies. Chlamydia psittaci DNA has been detected in 80\% of ocular adnexal lymphomas. The present pilot study was carried out to assess whether C psittaci-eradicating antibiotic therapy is associated with tumor regression in ocular adnexal lymphomas. PATIENTS AND METHODS: Nine patients with C psittaci-positive marginal-zone B-cell lymphoma of the ocular adnexa at diagnosis or relapse were treated with doxycycline 100 mg, bid orally, for 3 weeks. The presence of C psittaci DNA in peripheral-blood mononuclear cells (PBMCs) was also assessed before and after treatment in seven patients. Objective lymphoma regression was assessed 1, 3, and 6 months after therapy conclusion and every 6 months during follow-up. RESULTS: All patients completed antibiotic therapy with excellent tolerability. At 1 month from doxycycline assumption, chlamydial DNA was no longer detectable in PBMCs of all four positive patients. Objective response was complete in two patients, partial response (> 50\%) was observed in two patients, and minimal response (< 50\%) was observed in three patients. Duration of response in the seven responders was 12+, 29+, 31+, 8+, 7+, 2+, and 1+ months, respectively. CONCLUSION: C psittaci-eradicating antibiotic therapy with doxycycline is followed by objective response in patients with ocular adnexal lymphoma, even after multiple relapses of the disease. A confirmatory, large, phase II trial is warranted to confirm whether this fast, cheap, and well-tolerated therapy could replace other more aggressive strategies as first-line treatment against ocular adnexal lymphomas.
Abstract: Retinoic acid (RA) arrests the growth of EBV-immortalized lymphoblastoid B cell lines (LCLs) by upregulating the cyclin-dependent kinase inhibitor p27Kip1. Here, we show that in LCLs, RA inhibits ubiquitination and proteasome-dependent degradation of p27Kip1, a phenomenon that is associated with downregulation of Thr187 phosphorylation of the protein, whereas the phosphorylation on Ser10 is unaffected. Furthermore, we demonstrate that RA downregulates the expression of the p45Skp2 and Cks1 proteins, two essential components of the SCF(Skp2) ubiquitin ligase complex that target p27Kip1 for degradation. Downregulation of p45Skp2)and Cks1 occurs before the onset of growth arrest and is due to enhanced proteasome-mediated proteolysis of these proteins. Moreover, overexpression of p45Skp2 in DG75 cells prevents p27Kip1 protein accumulation and promotes resistance to the antiproliferative effects of RA. Treatment with Leptomycin B (LMB) blocked the translocation of p27Kip1 to the cytoplasm and prevented its degradation, indicating that CRM1-dependent nuclear export is required for p27Kip1 degradation. The shuttle protein p38Jab1, however, does not accumulate in the nucleus upon LMB treatment, nor does it interact with p27Kip1. Conversely, p45Skp2 is associated with p27Kip1 both in the nucleus and in the cytoplasm, accumulating within the nuclei after exposure to LMB and co-localizing with the exportin CRM1, suggesting a possible involvement of p45Skp2 in CRM1-dependent nuclear export of p27Kip1. These results indicate that downregulation of p45Skp2 is a key element underlying RA-induced p27Kip1 stabilization in B cells, resulting in an impaired targeting of the protein to the ubiquitin-proteasome pathway and probably contributing to the nuclear accumulation of p27Kip1.
Abstract: Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin's lymphoma with poor response to therapy and unfavorable prognosis. Here, we show that retinoic acid (RA) isomers significantly inhibit the proliferation of both primary MCL cultures (n = 7) and established cell lines (Granta 519 and SP-53) as shown by [(3)H]thymidine uptake and carboxyfluorescein diacetate succinimidyl ester labeling coupled with cyclin D1 staining. RA induces cell accumulation in G(0)-G(1) together with a marked up-regulation of p27(Kip1) by inhibiting ubiquitination and proteasome-dependent degradation of the protein. The p21(Cip1) inhibitor was also up-regulated by RA in Granta 519 cells, whereas the expression of cyclin D1 is unaffected. Most of RA-induced p27(Kip1) was bound to cyclin D1/cyclin-dependent kinase 4 complexes, probably contributing to the decreased cyclin-dependent kinase 4 kinase activity and pRb hypophosphorylation observed in RA-treated cells. Experiments with receptor-selective ligands indicate that RA receptor alpha cooperates with retinoid X receptors in mediating RA-dependent MCL cell growth inhibition. Notably, RA isomers, and particularly 9-cis-RA, also inhibited the growth-promoting effect induced in primary MCL cells by CD40 activation alone or in combination with interleukin-4. Immunohistochemical analysis showed that significant numbers of CD40L-expressing lymphoid cells are present in lymph node biopsies of MCL patients. These results therefore further strengthen the possibility that triggering of CD40 by infiltrating CD40L+ cells may continuously promote the growth of MCL cells in vivo. On these grounds, our findings that RA inhibits basal MCL proliferation as well as MCL growth-promoting effects exerted by microenvironmental factors make these compounds highly attractive in terms of potential clinical efficacy in this setting.
Abstract: The origin and biological significance of deletions at the 3' end of the Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP-1) gene are still controversial. We herein demonstrate that LMP-1 deletion mutants are highly associated with human immunodeficiency virus-related Hodgkin's lymphoma (HIV-HL) of Italian patients (29 of 31 cases; 93.5\%), a phenomenon that is not due to a peculiar distribution of EBV strains in this area. In fact, although HIV-HL patients are infected by multiple EBV variants, we demonstrate that LMP-1 deletion mutants preferentially accumulate within neoplastic tissues. Subcloning and sequencing of the 3' LMP-1 ends of two HIV-HL genes in which both variants were present showed the presence of molecular signatures suggestive of a likely derivation of the LMP-1 deletion mutant from a nondeletion ancestor. This phenomenon likely occurs within tumor cells in vivo, as shown by the detection of both LMP-1 variants in single microdissected Reed-Sternberg cells, and may at least in part explain the high prevalence of LMP-1 deletions associated with HIV-HL.
Abstract: BACKGROUND: Ocular adnexal lymphomas may be antigen-driven disorders; however, the source of the putative antigen or antigens is still unknown. Hence, we assessed whether Chlamydiae infection is associated with the development of ocular adnexal lymphomas. METHODS: The presence of Chlamydia psittaci, trachomatis, and pneumoniae DNA was investigated by polymerase chain reaction in 40 ocular adnexal lymphoma samples, 20 nonneoplastic orbital biopsies, 26 reactive lymphadenopathy samples, and peripheral blood mononuclear cells (PBMCs) from 21 lymphoma patients and 38 healthy individuals. Seven patients with chlamydia-positive PBMCs were treated with the antibiotic doxycycline, and objective response was assessed in four patients with measurable lymphoma lesions. Differences in Chlamydiae DNA detection between the case patients and the control subjects were analyzed using the Fisher exact test. All statistical tests were two-sided. RESULTS: Thirty-two of the 40 (80\%) ocular adnexal lymphoma samples carried C. psittaci DNA, whereas all lymphoma samples were negative for C. trachomatis and C. pneumoniae. In contrast, none of the 20 nonneoplastic orbital biopsies (0\% versus 80\%; P<.001) and only three of 26 (12\%) reactive lymphadenopathy samples (12\% versus 80\%; P<.001) carried the C. psittaci DNA. Nine of 21 (43\%) patients with chlamydia-positive lymphomas carried C. psittaci DNA in their PBMCs, whereas none (0\%) of the healthy PBMC donors carried C. psittaci DNA in their PBMCs (43\% versus 0\%; P<.001). One month after doxycycline treatment, chlamydial DNA was no longer detectable in the PBMCs of all seven treated patients, and objective response was observed in two of the four evaluable patients. CONCLUSION: Patients with ocular adnexal lymphoma had a high prevalence of C. psittaci infection in both tumor tissue and PBMCs. Persistent C. psittaci infection may contribute to the development of these lymphomas, as was also supported by the clinical responses observed in this study with C. psittaci-eradicating antibiotic therapy.
Abstract: IL-6-mediated B-cell growth promotion is involved in the pathogenesis of EBV+ lymphoproliferative disorders of immunosuppressed patients. Since retinoic acid (RA) inhibits the proliferation of EBV-immortalized lymphoblastoid B-cell lines (LCLs), we have investigated the effects of RA on IL-6 signaling in these cells. RA down-regulated IL-6-receptor components with IL-6 agonist activity (membrane and soluble gp80) and increased the levels of soluble gp130, an IL-6 antagonist. These changes, however, were not related to the enhanced production of endogenous IL-6 induced by RA in LCLs. RA-induced modulation of IL-6 receptor components did not abolish IL-6-mediated phosphorylation of gp130, whereas JAK1 and STAT3 phosphorylation and activation induced by IL-6 were markedly inhibited. Overall, the effects of RA resulted in the induction of a complete resistance of LCLs to IL-6-mediated growth promotion. Conversely, RA did not inhibit the constitutive activation of JAK1, TYK2, STAT3 and ERK1/2, ruling out that the JAK/STAT and MAPK pathways may mediate the antiproliferative activity of RA. The finding that RA severely impairs IL-6-dependent signalings in LCLs and inhibits their growth despite the presence of constitutively active JAK/STAT and MAPK cascades provide additional support for a role of RA in the prevention and treatment of EBV-related lymphoproliferative disorders of immunosuppressed patients.
Abstract: Human immunodeficiency virus-associated Hodgkin lymphoma frequently involves the bone marrow and is usually recognized at staging after Hodgkin lymphoma diagnosis on a lymph node or other tissue biopsies, but occasionally the marrow involvement is the only apparent manifestation of disease. In the latter setting, diagnosis can be problematic. From a total of 42 patients with newly diagnosed human immunodeficiency virus-associated Hodgkin lymphoma, 22 subjects had positive marrow involvement at diagnosis; 16 of them had additional substantial histological and/or clinical extramedullary Hodgkin lymphoma. In the remaining 6 patients the bone marrow was the only site of disease at diagnosis. In all six cases, bone marrow biopsy revealed obvious lymphomatous involvement. Reed-Sternberg cells were identified both morphologically and immunophenotypically in all cases. Spared marrow tissue consistently showed fibrosis. All patients were males with a median age of 35 years (range, 31-58 years). All presented with fever, blood cytopenias, and severe CD4+ lymphocyte depletion (median, 70 cells/mm(3)). After diagnosis, all staging procedures were negative, and all patients were treated with chemotherapy. Median survival was 4 months (range, 2-118 mo). Longer survival was achieved in the patients who completed chemotherapy regimens; three subjects, however, died shortly before the full completion of chemotherapy, two of them from Hodgkin lymphoma. Isolated bone marrow HIV-associated Hodgkin lymphoma may be an underestimated condition in HIV-infected patients; in those individuals with unexplained fever and blood cytopenias, bone marrow biopsy should be performed with the aim of assessing for Hodgkin lymphoma, even in the absence of nodal and visceral lymphomatous involvement. A rapid diagnosis of isolated bone marrow HIV-associated Hodgkin lymphoma could expedite therapy.
Abstract: Colorectal cancers with high-frequency microsatellite instability show peculiar clinicopathological features and a favorable clinical outcome. We investigated whether the improved prognosis for these cancers is related to the content of activated cytotoxic intraepithelial T lymphocytes. Microsatellite instability and the amount of activated cytotoxic lymphocytes were analyzed according to clinicopathological features, survival, and disease recurrence in 109 right-sided colon carcinomas from 245 consecutive patients with stage II/III colon cancer that underwent radical surgery. High-frequency microsatellite instability was found in 43\% of stage II/III proximal colon cancers and was associated with significantly higher numbers of activated cytotoxic lymphocytes. High-frequency microsatellite instability, as well as the content of intratumoral-activated cytotoxic T lymphocytes correlated with improved overall and disease-free survival, particularly in patients with stage III tumors. Multivariate analysis revealed that patients with both features had a risk of death and relapse markedly lower than that associated with microsatellite status or intratumoral cytotoxic lymphocytes separately. The presence of local cytotoxic immune responses is probably the major determinant of the good clinical course of patients with microsatellite unstable colon cancer. Furthermore, high-frequency microsatellite instability coupled with a high content of intratumoral cytotoxic lymphocytes may identify a subset of colon cancer patients with a favorable clinical outcome, particularly in stage III disease.
Abstract: In this study, we have characterized infiltrating T lymphocytes from 13 low-grade and 17 high-grade primary gastric MALT lymphomas by immunohistochemistry, with particular regard to the presence, activation, and topographic distribution of cytotoxic effectors. Although the prevalence of CD4+ and CD8+ cells was similar in low- and high-grade lymphomas, higher numbers of TIA-1+ cytotoxic effectors were found in this latter group of cases (11.6 versus 7. 8\%; P = 0.004). Activation of CD8+ cytotoxic T lymphocytes (CTLs) was significantly more pronounced in high- than in low-grade lymphomas, as shown by immunostaining for perforin (8.7 versus 4.0\%; P = 0.001) and granzyme-B (GrB) (8.7\% versus 3.0\%; P < 0.0001). Of note, CD20/GrB double labeling showed that high-grade lymphomas carried a markedly higher content (about ninefold) of activated CTLs relative to the number of CD20+ lymphoma B cells (0.081 +/- 0.076 versus 0.009 +/- 0.011; P < 0.0001). Moreover, high-grade lymphomas showed significantly increased apoptotic rates compared to low-grade cases (5.3 and 1.1\% of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells, respectively; P < 0.0001). In the whole series, the percentage of GrB+ cells and the GrB+/CD20+ ratio showed a strong linear correlation with the number of TUNEL-labeled cells. These findings, together with the frequent colocalization of CTLs and TUNEL+ neoplastic cells, suggested that apoptotic death of lymphoma cells may be due at least in part to the killing by cytotoxic effectors. Our results are consistent with the occurrence of host antitumor cell-mediated immune responses in gastric MALT lymphomas. Moreover, the finding of stronger cytotoxic responses in high- than in low-grade cases is of potential usefulness in the design of more effective therapeutic strategies for the management of these disorders.
Abstract: Microsatellite instability (MSI) characterizes colorectal carcinomas (CRCs) in hereditary nonpolyposis colorectal cancer (HNPCC) syndrome and a proportion of sporadic CRCs. These MSI+ CRCs share several clinicopathological features, including a reputation for better survival rates than MSI- cases and a pronounced stromal inflammatory reaction of still undefined nature. In the present study, the presence, spatial distribution, and activation status of infiltrating cytotoxic effectors were investigated comparatively in 18 MSI+ and 37 MSI- CRCs by immunohistochemistry. The frequency of apoptosis was also evaluated by morphology and in situ end-labeling. MSI+ cases carried significantly higher numbers of cytotoxic lymphocytes infiltrating within neoplastic epithelial structures, as shown by immunostaining for CD3 (15.1 +/- 6.2 versus 4.6 +/- 4.1, P < 0.001), CD8 (13 +/- 6.4 versus 3.7 +/- 3.8, P < 0.001), and TIA-1 (11.2 +/- 6.5 versus 1.9 +/- 1.7, P < 0.001). These cytotoxic effectors were globally more activated in MSI+ than in MSI- tumors, as revealed by the expression of granzyme B (5.3 +/- 4.5 versus 0.6 +/- 1.3, P < 0.001). In MSI+ CRCs, the number of intraepithelial activated cytotoxic lymphocytes was significantly correlated with the proximal location of the tumor, a poorly differentiated phenotype, and the presence of peritumor lymphoid nodules. Multivariate analysis revealed that MSI was the major determinant of the presence of activated cytotoxic intraepithelial lymphocytes. Moreover, MSI+ CRCs also showed a significantly higher percentage of tumor cells undergoing apoptotic cell death (4.1 +/- 2.1 versus 2.6 +/- 1.1, P < 0.0001, by the TUNEL method), often located in close proximity of activated cytotoxic lymphocytes. These results are consistent with the presence of anti-tumor cytotoxic immune responses in most of MSI+ CRCs, a phenomenon that may at least in part contribute to the survival advantage ascribed to these patients.
Abstract: AIMS AND BACKGROUND: Several simple molecular abnormalities have been detected in bronchial preneoplastic lesions, but the simultaneous presence of these alterations has been scarcely investigated. METHODS: We studied, by an immunohistochemical method, the expression of p53, Rb, Ras and Bcl-2 in 65 samples from surgical specimens and diagnostic biopsies selected for the presence of preneoplastic changes in the bronchial epithelium. To perform an analysis of the combined expression of all markers in the same areas, we accurately mapped every consecutive section on which immunohistochemical reactions were performed, subdividing each specimen into 25x microscopic fields, which allowed good topographical mapping. RESULTS: It was found that the frequency of p53-positive and Rb-negative microscopic fields was directly related to the morphological grading of lesions. On the other hand, Ras expression characterized high-grade lesions not showing squamous differentiation (non-squamous Cis). Regarding Bcl-2 expression, only slight differences in positivity distribution were found between the different lesions. More interesting was the parallel evaluation of all markers in the same areas: one of the main patterns, found to be correlated with the severity of histopathological features, was characterized by combined p53 hyperexpression/Rb hypoexpression; furthermore, when Ras and Bcl-2 hyperexpression were superimposed to the above pattern, the former mainly characterized non-squamous Cis, while the latter was present only in high-grade squamous lesions. However, the most frequently encountered pattern did not show any alteration of the studied markers, suggesting that other mechanisms could be involved in bronchial carcinogenesis. CONCLUSIONS: The detection of combined molecular abnormalities in bronchial preneoplasia could clarify the steps involved in lung carcinogenesis; furthermore, a simple and inexpensive method, such as immunohistochemistry, could be routinely applied also to cytologic specimens in order to detect those lesions, or patients, that are prone to progression towards lung cancer.
Abstract: We have studied by electron microscopy as well as by measurements of low shear viscosity, rigidity and binding, the effect of alpha-actinin on the gel formed at 37 degrees C with F-actin and with tropomyosin-decorated F-actin. Contrary to previous reports in the literature, alpha-actinin at nanomolar concentrations is an efficient actin gelling protein, even at 37 degrees C, provided that the concentration of actin (or of tropomyosin-decorated F-actin) is low (1.2-2.4 microM). The binding of alpha-actinin to F-actin, as a function of actin concentration, is anomalous. The amount of bound alpha-actinin increases when actin concentration increases from 0 to 1.2 microM but does not change significantly when actin concentration is further increased up to 48 microM. A similar result is obtained with tropomyosin-decorated F-actin. These observations can be explained by an hypothesis that binding is a function of the alpha-actinin - F-actin association constant as well as of the rigidity of the gel. When the concentration of actin increases, the rigidity of the gel also increases and more work is required to bring two actin filaments to the reaction distance with alpha-actinin and, consequently, a larger alpha-actinin concentration is required to attain the same ratio of bound alpha-actinin to actin monomers in the filaments.
Abstract: At 37 degrees C, in the presence of 0.1 M KC1 and 2 mM MgCl2, the binding of alpha-actinin to F-actin increases with the concentration of alpha-actinin but not with the concentration of F-actin. This implies that binding is determined by additional factors, beside the alpha-actinin - F-actin association constant. We propose that one of these factors is the rigidity of the gel, which cooperates negatively to the binding by increasing the work needed to bring two actin filaments at the reaction distance with alpha-actinin.
Abstract: Filamin increases and tropomyosin decreases the susceptibility of F-actin to form bundles of filaments in the presence of polyethylene glycol 6000. The two proteins, which are located in the leading edge and in the internal part of the cell, respectively, are thus likely to display divergent effects on the microfilaments into bundles transition in these two areas of the cell.
Abstract: At pH 7.5, in the presence of 0.1 M KCl, 2 mM MgCl2 and 15 mM phosphate, the binding of 1 molecule of alfa-actinin for each strand of 1000 actin monomers doubles the apparent viscosity of an F-actin solution (12 microM as the monomer). Further binding of one molecule of aldolase for each strand of 280 actin monomers halves the apparent viscosity of the alfa-actinin-F-actin system without any desorption of alfa-actinin. The effect of aldolase is not hindered by the addition of 0.1 mM fructose 1,6-bisphosphate. It is shown that orthophosphate acts as a damper of the regulatory effect of fructose bisphosphate on the interaction between aldolase and microfilaments.
Abstract: At 3 degrees C and pH 7.0, the addition of 40 nM ATP-G-actin to F-actin (12 microM as the monomer), polymerized in the presence of 4 mM CaCl2, determines a substantial and rapid increase of the viscosity of the solution, which is accompanied by the incorporation of the ATP-G-actin added into the polymer. The hypothesis that the presence of ATP-actin at the filament end(s) promotes the annealing reaction is substantiated by the finding that, after the addition of ATP-G-actin, the average filament length is increased. This finding is relevant, not only because it provides evidences in favour of the existence of annealing but also because it shows that the concentration of ATP-G-actin influences the filaments length distribution through a mechanism different from the elongation reaction.
