CD95 Receptor Research Articles

TCL-309: Prognostic Role of CD30 From a Retrospective Review of 295 Patients with Angioimmunoblastic T-Cell Lymphoma

Objective The main aim of this single-institution retrospective study was to elucidate the prognostic significance of CD30 expression in AITL. Methods We analyzed patients newly diagnosed with AITL at our institution between 2000 and 2020. Along with CD30 receptor testing, variables, including date of diagnosis, age, gender, stage, LDH level, platelets, hemoglobin, bone marrow involvement, and EBV receptor positivity, were collected. Treatment and progression data, including response to frontline therapy, presence of consolidation stem cell transplant (SCT), and usage of brentuximab-based treatment, were collected. Endpoints were progression-free survival (PFS) and OS. Univariate (UVA) and multivariate (MVA) Cox proportional hazard models were used to determine the significance of variables at diagnosis on PFS and OS. Results Out of the 295 individuals diagnosed with AITL, 129 patients with CD30 testing who had both response and survival data were included. This group had a median age of 65 (range 29–83) years and a male predominance (51%). Median follow-up time was 40 (range 2–137) months, with three-year PFS and OS of 48% and 23%, respectively. Sixty-seven individuals died within the first three years of the study. The 3-year OS is 46% in CD30+ individuals and 55% in those who are CD30– (p=0.578). PFS is 20% in CD30+ individuals and 29% in those who are CD30– (p=0.675). SCT (p=0.0003) was statistically associated with improved survival. For OS, age >65 (HR: 3.131, 95%CI: 1.545–6.344, p=0.0015), BM involvement (HR: 2.134, 95% CI: 1.151–3.956, p=0.0161), incomplete remission (HR: 2.208, 95% CI: 1–4.876, p=0.0499), male gender (HR: 0.367, 95% CI: 0.199–0.678, p=0.0014), no SCT (HR: 4.085, 95% CI: 2.119–7.872, p≤0.0001), and positive CD30 (HR: 0.322, 95% CI: 0.158–0.656, p=0.0018) were associated with inferior OS. Conclusion Age

Lymphomatoid papulosis in a 2-year-old child.

Lymphomatoid papulosis (LP) is a primary cutaneous T-cell lymphoma (6) characterized by clinical benignity despite its malignant histological appearance. Its incidence is 1.2-1.9/1,000,000; it is even rarer in the child (2). Its characteristic self-healing tendency has been attributed to the CD30 receptor glycoprotein which belongs to the superfamily of tumor necrosis factor and, interacting with its ligand, regulates cell survival and apoptosis (2, 7). However, the observation of the same self-healing clinical behavior in forms of LP characterized by the scarcity or absence of CD30+ cells clashes against this hypothesis. The most important problems of LP are the differential diagnosis from other benign and malignant disorders and the possible association with other malignancies. As regards the differential diagnosis, in the cases with one or a few nodules that arise in the hot period insect bites must be considered: the latter are symptomatic and rapidly reach their maximum size, unlike the nodules of LP that continue to grow for a couple of weeks. In forms with many elements, LP must be differentiated from pityriasis lichenoides, in which the elements are more numerous and smaller. The most difficult differential diagnosis is with CD30+ primary cutaneous anaplastic large cell lymphoma which has an identical histological picture, but whose nodules are less numerous, larger and above all do not regress spontaneously. As for the possible association of LP with other malignancies, especially lymphomas, it must be remembered that the latter arise in about 15% of cases in the first 5 years of follow-up; however, the percentage does not increase significantly in the following 5 years and does not exceed 20% after 25 years follow-up. In adults, the most frequent malignancy is mycosis fungoides (3). LP in the child does not differ from the adult form either clinically or histologically. Available data suggest that in children LP has a more indolent course, regresses more easily and is less frequently associated with malignancy (1). In a report on 35 patients with an average follow-up of 9 years the risk was 8.6% (4); in a recent meta-analysis of 251 children with LP (5) the incidence of lymphomas was 5.6%. However, the most frequent lymphoma in children is the primary cutaneous lymphoma with CD30+ large anaplastic cells. Lymphoma can arise before, during or after LP. The chance of developing extracutaneous lymphoma is greater in patients who have multifocal skin lesions.

Updates in the Treatment of Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of rare hematologic malignancies accounting for less than 10% of non-Hodgkin lymphomas. The 2016 classification of World Health Organization recognized 29 different entities of PTCLs. These subgroups are characterized by different molecular and genetic patterns. For nearly 30 years, little improvement in the treatment of PTCLs has been noticed due to the paucity of randomized trials and anthracycline-based chemotherapy remains the mainstay of first-line treatment. In front-line setting, ECHELON-2, the first randomized controlled Phase III clinical trial, recently met its primary endpoint of PFS demonstrating the superiority of BV containing regimen when compared to standard CHOP in patients with CD30 positive PTCLs. The role of therapeutic intensifications such as autologous or allogenic stem cell transplantations remains controversial in first-line setting and in relapsed/refractory disease due to the lack of studies clearly addressing this question and the recently published negative studies. PTCLs are often refractory to first-line chemotherapy and tend to relapse after an initial response. New agents have been approved for relapsed/refractory disease such as Histone deacetylase inhibitors, folate analogue metabolic inhibitor or CD30 antibody drug conjugated. Despite an acceptable response to these agents, progression-free survival remains very poor. New strategies such as combinations of different agents have been evaluated in order to improve outcomes. Innovative drugs in the fields of epigenetics, immunomodulation within the tumor microenvironment, and direct targeting of tumor cells to CD30 and T-cell receptor abnormalities open new perspectives to improve the treatment of PTCLs.

Linfoma T anaplásico de células grandes asociado a prótesis mamarias con afectación sistémica

Breast implant associated anaplastic large cell lymphoma (BIA-ALCL) is a rare type of T-cell lymphoma (cancer of the immune system) with an expression of the CD30 receptor. After the first case was described in 1997, more than 600 cases have been identified worldwide and. The published estimated lifetime risk of BIA-ALCL in international series ranges from 1:1000 to 1:10,000 women with textured breast implants. Many of these epidemiologic data are approximated, and it is a common opinion that the risk might be higher, especially for macrotextured high-surface implants. Mortality is very low because the lymphoma is mainly diagnosed in early stages.We hereby report one case of BIA-ALCL in a 78-year-old female who received a silicone breast implant. She showed a sudden breast volume increase and erythema that was diagnosed and treated as a mastitis that did not get better after antibiotics treatment. Some biopsies was taken and pathologic examination inform about a breast implant associated anaplastic large cell lymphoma. There were lymphadenopathies positive so a chemotherapy treatment was started. Patient had an excellent evolution and illness regression.

Bile Acid Toxicity and Protein Kinases.

If the bile acids reach to pathological concentrations due to cholestasis, accumulation of hydrophobic bile acids within the hepatocyte may result in cell death. Thus, hydrophobic bile acids induce apoptosis in hepatocytes, while hydrophilic bile acids increase intracellular adenosine 3',5'-monophosphate (cAMP) levels and activate mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways to protect hepatocytes from apoptosis.Two apoptotic pathways have been described in bile acids-induced death. Both are controlled by multiple protein kinase signaling pathways. In mitochondria-controlled pathway, caspase-8 is activated with death domain-independent manner, whereas, Fas-dependent classical pathway involves ligand-independent oligomerization of Fas.Hydrophobic bile acids dose-dependently upregulate the inflammatory response by further stimulating production of inflammatory cytokines. Death receptor-mediated apoptosis is regulated at the cell surface by the receptor expression, at the death-inducing signaling complex (DISC) by expression of procaspase-8, the death receptors Fas-associated death domain (FADD), and cellular FADD-like interleukin 1-beta (IL-1β)-converting enzyme (FLICE) inhibitory protein (cFLIP). Bile acids prevent cFLIP recruitment to the DISC and thereby enhance initiator caspase activation and lead to cholestatic apoptosis. At mitochondria, the expression of B-cell leukemia/lymphoma-2 (Bcl-2) family proteins contribute to apoptosis by regulating mitochondrial cytochrome c release via Bcl-2, Bcl-2 homology 3 (BH3) interacting domain death agonist (Bid), or Bcl-2 associated protein x (Bax). Fas receptor CD95 activation by hydrophobic bile acids is initiated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) signaling. However, activation of necroptosis by ligands of death receptors requires the kinase activity of receptor interacting protein1 (RIP1), which mediates the activation of RIP3 and mixed lineage kinase domain-like protein (MLKL). In this chapter, mainly the effect of protein kinases signal transduction on the mechanisms of hydrophobic bile acids-induced inflammation, apoptosis, necroptosis and necrosis are discussed.

Memory stem T cells modified with a redesigned CD30-chimeric antigen receptor show an enhanced antitumor effect in Hodgkin lymphoma.

ObjectivesAdoptive cell therapy (ACT) with mature T cells modified with a chimeric antigen receptor has demonstrated improved outcome for B‐cell malignancies. However, its application for others such as Hodgkin lymphoma remains a clinical challenge. CD30 antigen, expressed in Hodgkin lymphoma cells, is absent in most healthy tissues, representing an ideal target of ACT for this disease. Despite that, efficacy of CD30‐chimeric antigen receptor (CAR) T cells for Hodgkin lymphoma remains modest. Here, we have developed and tested a novel CD30‐CAR T to improve efficacy of CD30‐CAR therapy, using a targeting epitope within the non‐cleavable part of CD30 receptor, and memory stem T cells (TSCM) to improve engraftment, persistence and antitumor activity.MethodsTSCM‐like cultures were generated and expanded ex vivo and transduced at day 1 or 2 with a lentiviral vector encoding the CD30‐CAR. Therapeutic in vivo experiments were performed using NSG mice injected with L540 (sc) or L428 (iv) and treated with CD30‐CAR T cells when the tumor was established.ResultsCD30‐CAR TSCM‐like cells generated and expanded ex vivo, despite CD30 expression and fratricide killing of CD30+ CAR T cells, were not impaired by soluble CD30 and completely eradicated Hodgkin lymphoma in vivo, showing high persistence and long‐lasting immunity. In addition, highly enriched CD30‐CAR TSCM‐like products confer a survival advantage in vivo, in contrast to more differentiated CAR T cells, with higher tumor infiltration and enhanced antitumor effect.ConclusionThis study supports the use of a refined CD30‐CAR T cells with highly enriched TSCM‐like products to improve clinical efficacy of CAR T for Hodgkin lymphoma.

Primary cutaneous CD30+ Anaplastic large cell lymphoma

Defining features of Anaplastic large cell lymphoma (ALCL) consist of a proliferation of predominantly large lymphoid cells with a strong expression of the cytokine receptor CD30 and a characteristic growth pattern.

Downregulation of thioredoxin-1-dependent CD95 S-nitrosation by Sorafenib reduces liver cancer

Hepatocellular carcinoma (HCC) represents 80% of the primary hepatic neoplasms. It is the sixth most frequent neoplasm, the fourth cause of cancer-related death, and 7% of registered malignancies. Sorafenib is the first line molecular targeted therapy for patients in advanced stage of HCC. The present study shows that Sorafenib exerts free radical scavenging properties associated with the downregulation of nuclear factor E2-related factor 2 (Nrf2)-regulated thioredoxin 1 (Trx1) expression in liver cancer cells. The experimental downregulation and/or overexpression strategies showed that Trx1 induced activation of nitric oxide synthase (NOS) type 3 (NOS3) and S-nitrosation (SNO) of CD95 receptor leading to an increase of caspase-8 activity and cell proliferation, as well as reduction of caspase-3 activity in liver cancer cells. In addition, Sorafenib transiently increased mRNA expression and activity of S-nitrosoglutathione reductase (GSNOR) in HepG2 cells. Different experimental models of hepatocarcinogenesis based on the subcutaneous implantation of HepG2 cells in nude mice, as well as the induction of HCC by diethylnitrosamine (DEN) confirmed the relevance of Trx1 downregulation during the proapoptotic and antiproliferative properties induced by Sorafenib. In conclusion, the induction of apoptosis and antiproliferative properties by Sorafenib were related to Trx1 downregulation that appeared to play a relevant role on SNO of NOS3 and CD95 in HepG2 cells. The transient increase of GSNOR might also participate in the deactivation of CD95-dependent proliferative signaling in liver cancer cells.

Role of ADAM10 as a CD30 Sheddase in Classical Hodgkin Lymphoma.

Cancer cells generally recruit and influence non-malignant immune cells to support the tumor growth. Classical Hodgkin lymphoma (cHL) is a good example because the affected lymphoid tissue contains only a few malignant Hodgkin and Reed-Sternberg (H-RS) cells, which are supported by a massive infiltrate of lymphocytes, fibroblasts, and innate immune cells. The transmembrane receptor CD30, which is selectively expressed on the H-RS cells, plays an important role, not only in cell stimulation and intercellular communication but also in tumor diagnosis and targeted tumor therapy. Different protein processing pathways influence its functionality. Depending on the conditions, the receptor is internalized or released. The release of CD30 occurs either as an intact molecule, embedded in the membrane of extracellular vesicles (EVs), or as a cleaved soluble ectodomain (sCD30). CD30 cleavage is predominantly catalyzed by ADAM10. The enzyme is catalytically active in cells as well as in EVs and gradually releases sCD30. Because the circulation contains no CD30+ donor cells, this mechanism explains that the cleaved ectodomain represents the predominant form of CD30 in the plasma of cHL patients. CD30 processing might influence the impact of CD30 antibody-drug conjugates, such as Brentuximab Vedotin (BV). Whereas, ADAM10-degraded CD30 impedes the BV efficacy, tumor-derived EVs load bystander cells with CD30 and generate new targets among supporter cells. This crossfire effect might contribute to the enormous clinical impact of BV, whereas the ADAM10-dependent cleavage to the mild systemic off-target effects of the treatment with BV.

Synergistic Treatment of Tumor by Targeted Biotherapy and Chemotherapy via Site-Specific Anchoring of Aptamers on DNA Nanotubes.

BackgroundAptamers have been widely used as targeted therapeutic agents due to its relatively small physical size, flexible structure, high specificity, and selectivity. Aptamers functionalized nanomaterials, not only enhance the targeting of nanomaterials, but can also improve the stability of the aptamers. We developed aptamer C2NP (Apt) conjugated straight DNA nanotubes (S-DNT-Apt) and twisted DNA nanotubes (T-DNT-Apt) as nanocarriers for doxorubicin (DOX).MethodsThe twisted DNA nanotubes (T-DNT) and straight DNA nanotubes (S-DNT) were assembled with a scaffold and hundreds of staples. Apt was site-specifically anchored on DNA nanotubes with either different spatial distribution (3 or 6 nm) or varied stoichiometry (15Apt or 30Apt). The developed nanocarriers were characterized with agarose gel electrophoresis and transmission electron microscopy. The drug loading and release in vitro were evaluated by measuring the fluorescence intensity of DOX using a microplate reader. The stability of DNT in cell culture medium plus 10% of FBS was evaluated by agarose gel electrophoresis. The cytotoxicity of DNA nanostructures against K299 cells was tested with a standard CCK8 method. Cellular uptake, cell apoptosis, cell cycle and reactive oxygen species level were investigated by flow cytometry. The expression of p53 was examined by Western Blot.ResultsT-DNT-30Apt-6 exhibited the highest cytotoxicity when the concentration of Apt was 120 nM. After intercalation of DOX, the cytotoxicity of DOX@T-DNT-30Apt-6 was further enhanced due to the combination of chemotherapy of DOX and biotherapy of Apt. The enhanced cytotoxicity of DOX@T-DNT-30Apt-6 can be explained by the increase in the cellular uptake, cell apoptosis and intracellular ROS levels. Additionally, the interaction between Apt and its receptor CD30 could upregulate the expression of p53.ConclusionThese results demonstrate that both stoichiometry and spatial arrangement of Apt on T-DNT-Apt influence the anticancer activity. The developed twisted DNA nanotubes may be a solution for the synergistic treatment of cancer.

Fingolimod Augments Monomethylfumarate Killing of GBM Cells.

Previously we demonstrated that the multiple sclerosis drug dimethyl fumarate (DMF) and its plasma breakdown product MMF could interact with chemotherapeutic agents to kill both GBM cells and activated microglia. The trial NCT02337426 demonstrated the safety of DMF in newly diagnosed GBM patients when combined with the standard of care Stupp protocol. We hypothesized that another multiple sclerosis drug, fingolimod (FTY720) would synergize with MMF to kill GBM cells. MMF and fingolimod interacted in a greater than additive fashion to kill PDX GBM isolates. MMF and fingolimod radiosensitized glioma cells and enhanced the lethality of temozolomide. Exposure to [MMF + fingolimod] activated an ATM-dependent toxic autophagy pathway, enhanced protective endoplasmic reticulum stress signaling, and inactivated protective PI3K, STAT, and YAP function. The drug combination reduced the expression of protective c-FLIP-s, MCL-1, BCL-XL, and in parallel caused cell-surface clustering of the death receptor CD95. Knock down of CD95 or over-expression of c-FLIP-s or BCL-XL suppressed killing. Fingolimod and MMF interacted in a greater than additive fashion to rapidly enhance reactive oxygen species production and over-expression of either thioredoxin or super-oxide dismutase two significantly reduced the drug-induced phosphorylation of ATM, autophagosome formation and [MMF + fingolimod] lethality. In contrast, the production of ROS was only marginally reduced in cells lacking ATM, CD95, or Beclin1. Collectively, our data demonstrate that the primary generation of ROS by [MMF + fingolimod] plays a key role, via the induction of toxic autophagy and death receptor signaling, in the killing of GBM cells.

NK Cell Impairment after Haploidentical Allogeneic Hematopoietic Cell Transplant in Patients Receiving Post-Transplant Cyclophosphamide (PTCy)

Haploidentical hematopoietic cell transplantation (haplo-HCT) with post-transplant cyclophosphamide (PTCy) as graft versus host disease (GVHD) prophylaxis is frequently used for patients who do not have HLA-identical donors. However, the effect of PTCy on immune reconstitution (IR) has not been studied extensively in large prospective cohorts, despite a high incidence of early viral infections. We quantified IR in 60 patients after haplo-HCT with PTCy, mycophenolate mofetil and tacrolimus (TAC) and compared results to 34 patients with 8/8 HLA matched related or unrelated donors (MD) receiving TAC and methotrexate for GVHD prophylaxis. Both groups received reduced intensity conditioning for hematologic malignancies. Samples were prospectively collected at 1, 2, 3, 6, 9, 12, 18, 24 and 30 months after HCT and analyzed using multi-color flow cytometry to characterize distinct lymphocyte populations. Peripheral blood NK cells 1 month after PTCy were characterized using CyTOF and a panel of 35 metal-labeled monoclonal antibodies and compared to age-matched healthy donor NK cells. Recovery of all T cell subsets (CD4Tcon, CD4Treg, CD8) was significantly reduced in the PTCy cohort compared to MD early after HCT (Figure 1A, B, C). Despite delayed CD4Treg recovery, the Treg:Tcon ratio was significantly higher early after HCT in the PTCY cohort due to relatively deeper depression in CD4Tcon (0.18 vs 0.06, p<0.0001 at 1 month, 0.12 vs 0.06, p=0.0004 at 3 months, Figure 1D). Absolute NK cells were lower at 1 month after PTCy (Figure 1E), entirely due to reduced numbers of CD56^dimCD16⁺ NK cells (Figure 1G). Subsequently, CD56^dim NK cells remained significantly lower in the PTCy group until 3 months after HCT. In contrast, recovery of CD56^brightCD16⁻ NK cells was significantly increased in the PTCy cohort at 2, 3 and 6 months after HCT (p<0.01. Figure 1F). The distribution of NK subsets 1 month post-HCT was also significantly different between two cohorts due to a higher frequency of immature NK cells in the PTCY cohort (Figure 1H). CyTOF analysis performed 1 month after haplo-HCT showed that NK cells expressed higher level of activating receptor NKp46, CD95, granzyme-B and inhibitory receptor NKG2A and lower expression of CD57 compared to HD (Figure 2). Functional assays showed that PTCy NK cells displayed reduced degranulation and release of IFNγ after activation compared to HD. These functions were rescued after priming with low dose IL-15 in vitro. In summary, the effect of PTCy on IR was most pronounced at 1 month with significantly delayed recovery of CD3, CD4Tcon, CD4Treg, CD8 and CD56^dim NK cells. After PTCy, NK cells display an immature phenotype and functional impairment that is at least partly corrected by priming with low dose IL-15. Impairment of NK and T cell recovery early after PTCy-based HCT underscores the need to adopt novel strategies to overcome immune defects induced by this platform.

Blockade of CD95/CD95L Death Signaling Enhances CAR T Cell Persistence and Antitumor Efficacy

Introduction Despite the encouraging outcome of anti-CD19 chimeric antigen receptor T (CAR T) cell therapy in patients with B cell malignancies, CAR T cell persistence remains a major clinical challenge. Activation-induced cell death (AICD) is a programmed cell death caused by the interaction of CD95 and CD95L. Through specific blocking of the CD95-CD95L pathway, the CD95L inhibitor APG101 (Asunercept, Apogenix AG, Heidelberg) could prevent activated T cells from AICD. APG101 is a fully human fusion protein consisting of the extracellular domain of CD95 receptor and the Fc domain of an IgG antibody. Thus, we evaluated whether a blockade of the CD95L pathway through APG101 might improve CAR T cell persistence and enhance antitumor efficacy. Methods Human peripheral blood mononuclear cells (PBMCs) from healthy donors were stimulated by plate-bound CD3 and CD28 antibodies, and thereafter transduced with a 3rd generation CD19.CAR.CD28.CD137zeta retroviral vector. An in vitro co-culture stress test assay was employed to assess the functional status and viability of CD19.CAR T cells upon repetitive stimulation with CD19+ tumor cells, i.e. Daudi cells. CAR T cells (5.0 x 105 per well) were co-cultured with tumor cells at a 1:1 E:T ratio (round I) in the presence of APG101. Additional tumor cells were supplied to the co-culture every 24 hours. After 3 rounds (72 hr) of stimulation, tumor cells (CD3-CD19+) and CAR T cells (CD3+CD19-) were harvested for FACS analysis. To assess the antigen-induced CAR T cell proliferation, CAR T cells were preloaded with Cell Trace Violet cytosolic dye and cocultured with tumor cells for 72 hours. Results Activation-induced cell death of CAR T cells was observed after repeated antigenic stimulation, accompanied by increased CD95L expression. CD4+ CAR T cells were more susceptible to AICD compared to CD8+ CAR T cells. But, there was no difference in the expression of CD95L between CD4+ and CD8+ CAR T cells. Interestingly, addition of APG101 significantly inhibited CD95L expression and resulted in a lower level of CAR T cell death. Importantly, APG101 did not hamper the activation and proliferation of CAR T cells but was able to restore CAR T cell viability. The expression of PD1, TIM3 and LAG3 were also up-regulated after successive stimulation, however, their expression on CAR T cells were not influenced by APG101. After 3 days of co-culture, the number of CAR T cells increased in the presence of APG101 (7.9 x 105 vs6.0 x 105, P = 0.01) and residual tumor cells were diminished (1.7 x 105 vs2.7 x 105, P = 0.02). Of note, APG101 itself did not affect CAR T cells or tumor cells when cultured separately. Moreover, the central memory CAR T (TCM) cell subset showed higher CD95L expression after coculturing which could be inhibited by APG101. Therefore, the addition of APG101 to the coculture resulted in a significant accumulation of TCM subset after APG101 treatment. Conclusion Upregulation of CD95L after repeated antigen stimulation was reversed by APG101. CD95L blockade enhanced CAR T cell survival and promoted killing of tumor cells in vitro. Combining CAR T cell therapy with CD95L inhibitor might improve CAR T cell persistence in vivo and thus enhance the effect of CAR T cell therapy. Disclosures Schmitt: Therakos Mallinckrodt: Other: Financial Support . Kneisel:Apogenix AG: Employment. Hoeger:Apogenix AG: Employment, Membership on an entity's Board of Directors or advisory committees. Schmitt:MSD: Membership on an entity's Board of Directors or advisory committees, Other: Sponsoring of Symposia; Therakos Mallinckrodt: Other: Financial Support.

3D Cellular Architecture Modulates Tyrosine Kinase Activity, Thereby Switching CD95-Mediated Apoptosis to Survival

The death receptor CD95 is expressed in every cancer cell, thus providing a promising tool to target cancer. Activation of CD95 can, however, lead to apoptosis or proliferation. Yet the molecular determinants of CD95's mode of action remain unclear. Here, we identify an optimal distance between CD95Ligand molecules that enables specific clustering of receptor-ligand pairs, leadingto efficient CD95 activation. Surprisingly, efficientCD95 activation leads to apoptosis in cancer cells invitro and increased tumor growth invivo. We show that allowing a 3D aggregation of cancercells invitro switches the apoptotic response to proliferation. Indeed, we demonstrate that the absence or presence of cell-cell contactsdictates the cell response to CD95. Cellcontacts increase global levels of phosphorylated tyrosines, including CD95's tyrosine. A tyrosine-to-alanine CD95 mutant blocks proliferation in cellsin contact. Our study sheds light intothe regulatory mechanism of CD95 activation that canbe further explored for anti-cancer therapies.

CD30 Cross-Reactivity and Expression in Feline Normal Tissues and Lymphomas.

CD30 is a transmembrane glycoprotein of the tumor necrosis factor receptor superfamily included in the diagnostic algorithm of human cutaneous, anaplastic large cell and Hodgkin lymphomas and represents an optimal therapeutic target for CD30+ tumors. Similar diagnostic and therapeutic approaches are largely missing for feline lymphomas. Cross-reactivity of the antihuman CD30 receptor clone Ber-H2 was investigated in feline lymphomas. Comparative analysis of feline and human CD30 identified 61% identity of the amino acid sequence, with 100% identity of the main sequence of the epitope targeted by the antibody (RKQCEPDYYL). CD30 expression in normal feline tissues was restricted to rare lymphoid cells in perifollicular and interfollicular lymph node areas and in the thymic medulla. In feline lymphoma, CD30 was expressed in 4 of 33 (13%) T-cell lymphomas, 3 of 22 (14%) B-cell lymphomas, and 5 of 7 (71%) mixed-cell lymphomas, showing diffuse (1/5) or multifocal (4/5) positivity restricted to neoplastic multinucleated lymphoid cells and binucleated cells consistent with Reed-Sternberg-like cells. Based on the human classification system, cell morphology, expression of multiple markers (mixed cell components), and CD30 positivity, these cases were considered most consistent with classical Hodgkin-like lymphoma (HLL). The other 2 mixed-cell lymphomas were CD30 negative and thus most consistent with either T-cell-rich large B-cell lymphoma (TCRLBCL) or nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). These findings provide multiple data supporting the cross-reactivity of the Ber-H2 anti-CD30 clone in feline tissues and give evidence of the usefulness of CD30 in the diagnostic evaluation of feline lymphoma.

Probing the side chain tolerance for inhibitors of the CD95/PLCγ1 interaction.

Proceeding our effort to study protein-protein interaction between the death receptor CD95 and phospholipase PLCγ1, we present in the current work chameleon-like traits of peptidomimetic inhibitors. Minute analysis of the interaction suggests that most of the binding energy relies on van der Waals contacts rather than more specific features, such as hydrogen bonds or salt bridges. The two most important positions of the peptoid for its interaction with PLCγ1 (Arg184 and Arg187) were modified to test this hypothesis. While Arg184 proves to be exchangeable for Trp, with no alteration in affinity, the nature of the amino acid replacing Arg187 is more dependent on its positive charge. However, affinity can be partially recovered by increasing van der Waals interactions. Overall, this study shows that for both positions, a subtle balance exists between hydrophobicity, surface contacts and affinity for CD95/PLCγ1, and provides information for the generation of new therapeutic compounds toward this druggable target.

Repression of Death Receptor–Mediated Apoptosis of Hepatocytes by Hepatitis B Virus e Antigen

Hepatitis B virus (HBV) e antigen (HBeAg) is associated with viral persistence and pathogenesis. Resistance of HBV-infected hepatocytes to apoptosis is seen as one of the primary promotors for HBV chronicity and malignancy. Fas receptor/ligand (Fas/FasL) and the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) system plays a key role in hepatic death during HBV infection. We found that HBeAg mediates resistance of hepatocytes to FasL or TRAIL-induced apoptosis. Introduction of HBeAg into human hepatocytes rendered resistance to FasL or TRAIL cytotoxicity in a p53-dependent manner. HBeAg further inhibited the expression of p53, total Fas, membrane-bound Fas, TNF receptor superfamily member 10a, and TNF receptor superfamily member 10b at both mRNA and protein levels. Incontrast, HBeAg enhanced the expression of soluble forms of Fas through facilitation of Fas alternative mRNA splicing. In a mouse model, expression of HBeAg in mice injected with recombinant adenovirus-associated virus 8 inhibited agonistic anti-Fas antibody-induced hepatic apoptosis. Xenograft tumorigenicity assay also found that HBeAg-induced carcinogenesis was resistant to the proapoptotic effect of TRAIL and chemotherapeutic drugs. These results indicate that HBeAg may prevent hepatocytes from FasL and TRAIL-induced apoptosis by regulating the expression of the proapoptotic and antiapoptotic forms of death receptors, which may contribute to the survival and persistence of infected hepatocytes during HBV infection.

Synthesis of peptidomimetics and chemo-biological tools for CD95/PLCγ1 interaction analysis.

The death receptor CD95 (also known as Fas) induces apoptosis through protein/protein association and the formation of the death-inducing signaling complex. On the other hand, in certain biological conditions, this receptor recruits different proteins and triggers the formation of another complex designated motility-inducing signaling complex, which promotes cell migration and inflammation. This pathway relies on a short sequence of CD95, called calcium-inducing domain (CID), which interacts with the phospholipase PLCγ1. To better understand how CID/PLCγ1 interaction occurs, we synthesized different α-AA peptides mimicking CID. Some of these peptidomimetics are as potent as the natural peptide to disrupt the CID/PLCγ1 interaction and cell migration, and showed improved pharmacokinetic properties. We also generated biotinyl- and palmitoyl-labelled peptidomimetics, useful chemico-biological tools to further explore the pro-inflammatory signal of CD95, which plays an important role in the pathogenesis of lupus and other autoimmune diseases.

Chronic CD30 signaling in B cells results in lymphomagenesis by driving the expansion of plasmablasts and B1 cells

AbstractCD30 is expressed on a variety of B-cell lymphomas, such as Hodgkin lymphoma, primary effusion lymphoma, and a diffuse large B-cell lymphoma subgroup. In normal tissues, CD30 is expressed on some activated B and T lymphocytes. However, the physiological function of CD30 signaling and its contribution to the generation of CD30+ lymphomas are still poorly understood. To gain a better understanding of CD30 signaling in B cells, we studied the expression of CD30 in different murine B-cell populations. We show that B1 cells expressed higher levels of CD30 than B2 cells and that CD30 was upregulated in IRF4+ plasmablasts (PBs). Furthermore, we generated and analyzed mice expressing a constitutively active CD30 receptor in B lymphocytes. These mice displayed an increase in B1 cells in the peritoneal cavity (PerC) and secondary lymphoid organs as well as increased numbers of plasma cells (PCs). TI-2 immunization resulted in a further expansion of B1 cells and PCs. We provide evidence that the expanded B1 population in the spleen included a fraction of PBs. CD30 signals seemed to enhance PC differentiation by increasing activation of NF-κB and promoting higher levels of phosphorylated STAT3 and STAT6 and nuclear IRF4. In addition, chronic CD30 signaling led to B-cell lymphomagenesis in aged mice. These lymphomas were localized in the spleen and PerC and had a B1-like/plasmablastic phenotype. We conclude that our mouse model mirrors chronic B-cell activation with increased numbers of CD30+ lymphocytes and provides experimental proof that chronic CD30 signaling increases the risk of B-cell lymphomagenesis.

CD95/Fas and metastatic disease: What does not kill you makes you stronger.

CD95 (also known as Fas) is the prototype of death receptors; however, evidence suggests that this receptor mainly implements non-apoptotic signaling pathways such as NF-κB, MAPK, and PI3K that are involved in cell migration, differentiation, survival, and cytokine secretion. At least two different forms of CD95 L exist. The multi-aggregated transmembrane ligand (m-CD95 L) is cleaved by metalloproteases to release a homotrimeric soluble ligand (s-CD95 L). Unlike m-CD95 L, the interaction between s-CD95 L and its receptor CD95 fails to trigger apoptosis, but instead promotes calcium-dependent cell migration, which contributes to the accumulation of inflammatory Th17 cells in damaged organs of lupus patients and favors cancer cell invasiveness. Novel inhibitors targeting the pro-inflammatory roles of CD95/CD95 L may provide attractive therapeutic options for patients with chronic inflammatory disorders or cancer. This review discusses the roles of the CD95/CD95 L pair in cell migration and metastasis.