CD27 signals through PKC in human B cell lymphomas

The CD70-CD27 axis in oncology: the new kids on the block

The immune checkpoint molecule CD70 and its receptor CD27 are aberrantly expressed in many hematological and solid malignancies. Dysregulation of the CD70-CD27 axis within the tumor and its microenvironment is associated with tumor progression and immunosuppression. This is in contrast to physiological conditions, where tightly controlled expression of CD70 and CD27 plays a role in co-stimulation in immune responses. In hematological malignancies, cancer cells co-express CD70 and CD27 promoting stemness, proliferation and survival of malignancy. In solid tumors, only expression of CD70 is present on the tumor cells which can facilitate immune evasion through CD27 expression in the tumor microenvironment. The discovery of these tumor promoting and immunosuppressive effects of the CD70-CD27 axis has unfolded a novel target in the field of oncology, CD70.

In this review, we thoroughly discuss current insights into expression patterns and the role of the CD70-CD27 axis in hematological and solid malignancies, its effect on the tumor microenvironment and (pre)clinical therapeutic strategies.

New Generation of Meso and Antiprogestins (SPRMs) into the Osteoporosis Approach

Receptor activator of nuclear factor κB (RANK) and its ligand (RANKL) play key roles in bone metabolism and the immune system. The RANK/RANKL complex has also been shown to be critical in the formation of mammary epithelia cells. The female hormones estradiol and progesterone closely control the action of RANKL with RANK. Blood concentration of these sex hormones in the postmenopausal period leads to an increase in RANK/RANKL signaling and are a major cause of women's osteoporosis, characterized by altered bone mineralization. Knowledge of the biochemical relationships between hormones and RANK/RANKL signaling provides the opportunity to design novel therapeutic agents to inhibit bone loss, based on the anti-RANKL treatment and inhibition of its interaction with the RANK receptor. The new generation of both anti- and mesoprogestins that inhibit the NF-κB-cyclin D1 axis and blocks the binding of RANKL to RANK can be considered as a potential source of new RANK receptor ligands with anti-RANKL function, which may provide a new perspective into osteoporosis treatment itself as well as limit the osteoporosis rise during breast cancer metastasis to the bone.

Potential Molecular Mechanisms of Rare Anti-Tumor Immune Response by SARS-CoV-2 in Isolated Cases of Lymphomas

Recently, two cases of complete remission of classical Hodgkin lymphoma (cHL) and follicular lymphoma (FL) after SARS-CoV-2 infection were reported. However, the precise molecular mechanism of this rare event is yet to be understood. Here, we hypothesize a potential anti-tumor immune response of SARS-CoV-2 and based on a computational approach show that: (i) SARS-CoV-2 Spike-RBD may bind to the extracellular domains of CD15, CD27, CD45, and CD152 receptors of cHL or FL and may directly inhibit cell proliferation. (ii) Alternately, upon internalization after binding to these CD molecules, the SARS-CoV-2 membrane (M) protein and ORF3a may bind to gamma-tubulin complex component 3 (GCP3) at its tubulin gamma-1 chain (TUBG1) binding site. (iii) The M protein may also interact with TUBG1, blocking its binding to GCP3. (iv) Both the M and ORF3a proteins may render the GCP2-GCP3 lateral binding where the M protein possibly interacts with GCP2 at its GCP3 binding site and the ORF3a protein to GCP3 at its GCP2 interacting residues. (v) Interactions of the M and ORF3a proteins with these gamma-tubulin ring complex components potentially block the initial process of microtubule nucleation, leading to cell-cycle arrest and apoptosis. (vi) The Spike-RBD may also interact with and block PD-1 signaling similar to pembrolizumab and nivolumab- like monoclonal antibodies and may induce B-cell apoptosis and remission. (vii) Finally, the TRADD interacting "PVQLSY" motif of Epstein-Barr virus LMP-1, that is responsible for NF-kB mediated oncogenesis, potentially interacts with SARS-CoV-2 Mpro, NSP7, NSP10, and spike (S) proteins, and may inhibit the LMP-1 mediated cell proliferation. Taken together, our results suggest a possible therapeutic potential of SARS-CoV-2 in lymphoproliferative disorders.

CD70 reverse signaling enhances NK cell function and immunosurveillance in CD27-expressing B-cell malignancies

CD27 expression on malignant B cells triggers CD70 reverse signaling in NK cells and improves lymphoma immunosurveillance. CD70 reverse signaling in NK cells is mediated via the AKT signaling pathway and enhances survival and effector function.

Receptor-specific signaling for both the alternative and the canonical NF-kappaB activation pathways by NF-kappaB-inducing kinase

The NF-kappaB-inducing kinase (NIK) induces proteolytic processing of NF-kappaB2/p100 and, hence, the generation of NF-kappaB dimers such as p52:RelB but was suggested not to signal for the processing of IkappaB. Here, we show that although the induction of IkappaB degradation in lymphocytes by TNF is independent of NIK, its induction by CD70, CD40 ligand, and BLyS/BAFF, which all also induce NF-kappaB2/p100 processing, does depend on NIK function. Both CD70 and TNF induce recruitment of the IKK kinase complex to their receptors. In the case of CD70, but not TNF, this process is associated with NIK recruitment and is followed by prolonged receptor association of just IKK1 and NIK. Recruitment of the IKK complex to CD27, but not that of NIK, depends on NIK kinase function. Our findings indicate that NIK participates in a unique set of proximal signaling events initiated by specific inducers, which activate both canonical and noncanonical NF-kappaB dimers.

Phenotypic characterization of subsets of T cell lymphoma: towards a functional classification of T cell lymphoma

T cell non-Hodgkin's lymphomas (T-NHL) have traditionally been classified according to a variety of criteria including histological and clinical features, sites of involvement and etiologic agents. Except in select T-NHL types (e.g. CD30-positive anaplastic large cell lymphoma (ALCL)), immunophenotypic criteria are not used for routine subclassification of T-NHL. In this article. we outline the current models for classification and diagnosis of T cell tumors. We also briefly review the current understanding of non-neoplastic T cell subsets with regards to expression of activation markers belonging to the tumor necrosis factor receptor (TNFR) gene family. We summarize the currently available information on expression of these subset markers in T cell tumors, focusing on TNFR family members CD30 and CD134/OX40. CD134/OX40 expression is characteristic of certain entities (angioimmunoblastic lymphoma, angiocentric T-NHL) and a subset of T-NHLs of unspecified type, whereas CD30 expression is characteristic of ALCL and a largely non-overlapping subset of T-NHLs of unspecified type. Immunophenotypic stratification of T-NHL, using TNFR family members and other T cell subset-specific gene products, may provide a functional model for T-NHL classification as is currently the case for B cell tumors.