Human CD30: structural implications from epitope mapping and modeling studies

CD30 in Cutaneous Pathology

ABSTRACT

The discovery of CD30 as a diagnostic marker was essential in the identification of not only some lymphomas but also many other solid tumors and benign reactive conditions. Many CD30+ cutaneous disorders and tumors have been categorized since the identification of the marker. With the design of targeted therapies against CD30+ tumoral cells, the interest in CD30 determination was not only diagnostic but also mainly therapeutic. In this article, we explore the historical aspects of the discovery of CD30 and examine the main CD30-related cutaneous pathology, susceptible of anti-CD30 modern treatments.

New molecular targets in Hodgkin and Reed-Sternberg cells

Recent discoveries shed light on molecular mechanisms responsible for classical Hodgkin lymphoma (HL) development and progression, along with features of Hodgkin - Reed and Sternberg cells (HRS). Here, we summarize current knowledge on characteristic molecular alterations in HL, as well as existing targeted therapies and potential novel treatments for this disease. We discuss the importance of cluster of differentiation molecule 30 (CD30) and the programmed cell death-1 protein (PD-1) and ligands (PD-L1/2), and other molecules involved in immune modulation in HL. We highlight emerging evidence indicating that the altered function of SWI/SNF-type chromatin remodeling complexes, PRC2, and other epigenetic modifiers, contribute to variations in chromatin status, which are typical for HL. We postulate that despite of the existence of plentiful molecular data, the understanding of HL development remains incomplete. We therefore propose research directions involving analysis of reverse signaling in the PD-1/PD-L1 mechanism, chromatin remodeling, and epigenetics-related alterations, in order to identify HL features at the molecular level. Such attempts may lead to the identification of new molecular targets, and thus will likely substantially contribute to the future development of more effective targeted therapies.

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 M^pro, 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.

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.

Understanding CD30 biology and therapeutic targeting: a historical perspective providing insight into future directions

CD30 is a member of the tumor necrosis factor receptor superfamily. It is characteristically expressed in certain hematopoietic malignancies, including anaplastic large cell lymphoma and Hodgkin lymphoma, among others. The variable expression of CD30 on both normal and malignant lymphoid cells has focused research efforts on understanding the pathogenesis of CD30 upregulation, its contribution to lymphomagenesis through anti-apoptotic mechanisms, and its effect on cell survival. Given the restriction of CD30 to certain tumor types, the logical extension of this has been to attempt to exploit it as a therapeutic target. The efficacy of naked anti-CD30 antibodies in practice was, however, modest. Moreover, combinations with bacterial toxins and radioimmunoconjugates have also had limited success. The development of the antibody-drug compound brentuximab vedotin (BV), however, has rejuvenated interest in CD30 as a tumor target. Phase I and II clinical trials in Hodgkin lymphoma, peripheral T-cell lymphoma, cutaneous T cell lymphoma, and even CD30-expressing B-cell lymphomas, have shown the compound is well tolerated, but more importantly, able to deliver meaningful disease control even in patients with multiply relapsed or refractory disease. FDA approval has been granted for its use in relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma. A recent phase III trial of BV in cutaneous T-cell lymphoma has confirmed its superiority to standard of care therapies. In this manuscript, we explore the history of CD30 as a tumor marker and as a therapeutic target, both in the laboratory and in the clinic, with a view to understanding future avenues for further study.

Real-time surface plasmon resonance imaging measurements for the multiplexed determination of protein adsorption/desorption kinetics and surface enzymatic reactions on peptide microarrays

The kinetics of protein adsorption/desorption onto peptide microarrays was studied using real-time surface plasmon resonance (SPR) imaging. S protein binding interactions were examined using an array composed of five different peptides: N terminal and C terminal immobilized wild-type S peptide (S1 and S2), an alternate binding sequence derived by phage display (LB2), an NVOC-protected S peptide, and a FLAG peptide control sequence (F). Kinetic measurements of the S protein-S1 peptide interaction were analyzed to determine a desorption rate constant (k(d)) of 1.1 (+/-0.08) x 10(-2) s(-1), an adsorption rate constant (k(a)) of 1.9 (+/-0.05) x 10(5) M(-1) s(-1), and an equilibrium adsorption constant (K(Ads)) of 1.7 (+/-0.08) x 10(7) M(-1). SPR imaging equilibrium measurements of S protein to S1 peptide were performed to independently confirm the kinetically determined value of K(Ads). Rate constants for the S2 and LB2 peptides on the array were measured as follows: 1.6 (+/-0.04) x 10(5) M(-1) s(-1) (k(a)) and 1.1 (+/-0.07) x 10(-2) s(-1) (k(d)) for S2, 1.2 (+/-0.05) x 10(5) M(-1) s(-1) (k(a)) and 1.1 (+/-0.03) x 10(-2) s(-1) (k(d)) for LB2. In addition to S protein adsorption/desorption, real-time SPR imaging of peptide arrays was applied to study the surface enzymatic activities of the protease factor Xa. Enzymatic cleavage of the substrate peptide (P1) was shown to follow first-order kinetics and proceed at a rate 10 times faster than that of the mutant peptide (P2), with cleavage velocities of 5.6 (+/-0.3) x 10(-4) s(-1) for P1 and 5.7 (+/-0.3) x 10(-5) s(-1) for P2.

Elevation of plasma membrane permeability by laser irradiation of selectively bound nanoparticles

Irradiation of nanoabsorbers with pico- and nanosecond laser pulses could result in thermal effects with a spatial confinement of less than 50 nm. Therefore absorbing nanoparticles could be used to create controlled cellular effects. We describe a combination of laser irradiation with nanoparticles, which changes the plasma membrane permeability. We demonstrate that the system enables molecules to penetrate impermeable cell membranes. Laser light at 532 nm is used to irradiate conjugates of colloidal gold, which are delivered by antibodies to the plasma membrane of the Hodgkin's disease cell line L428 and/or the human large-cell anaplastic lymphoma cell line Karpas 299. After irradiation, membrane permeability is evaluated by fluorescence microscopy and flow cytometry using propidium iodide (PI) and fluorescein isothiocyanate (FITC) dextran. The fraction of transiently permeabilized and then resealed cells is affected by the laser parameter, the gold concentration, and the membrane protein of the different cell lines to which the nanoparticles are bound. Furthermore, a dependence on particle size is found for these interactions in the different cell lines. The results suggest that after optimization, this method could be used for gene transfection and gene therapy.

The fully human anti-CD30 antibody 5F11 activates NF-κB and sensitizes lymphoma cells to bortezomib-induced apoptosis

5F11, a fully human monoclonal antibody directed against CD30, effectively induces killing of CD30-expressing lymphoma cell lines in vitro and in animal models. A recently conducted phase 1/2 study shows that 5F11 is well tolerated in heavily pretreated patients with relapsed and refractory CD30+ lymphoma and has some clinical activity. In the present study, we demonstrate that 5F11 activates nuclear factor κB (NF-κB) and the anti-apoptotic protein cellular FLICE (Fas-associating protein with death domain-like interleukin-1β-converting enzyme) inhibitory protein (c-flip) in Hodgkin lymphoma (HD)-derived cell lines, which might cause apoptosis resistance, thus limiting the clinical use of 5F11. To overcome this resistance, we combined 5F11 with the proteasome inhibitor bortezomib, which has been shown to suppress NF-κB activity. This combination revealed a synergistic cytotoxic effect in vitro and in a human HD xenograft model provided that 5F11 precedes bortezomib treatment. We conclude that initial 5F11-mediated NF-κB signaling sensitizes the tumor cells to bortezomib-induced cell death. These data suggest a therapeutic value of this combination for HD patients. (Blood. 2005;106:1839-1842)

Survey of the year 2003 commercial optical biosensor literature

In the year 2003 there was a 17% increase in the number of publications citing work performed using optical biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as biosensor technology continues to mature.

The ectodomain shedding of CD30 is specifically regulated by peptide motifs in its cysteine-rich domains 2 and 5

Tumor necrosis factor (TNF)-alpha converting enzyme (TACE) is responsible for the ectodomain release of various membrane proteins by proteolytic cleavage in close proximity to the cell membrane. Despite the wide spectrum of possible substrates, selective cleavage can be achieved by substrate cross-linking. To explore the underlying mechanism, we studied the TACE-mediated shedding of CD30. Whereas the constitutive release of the soluble ectodomain of CD30 (sCD30) from the lymphoma cell line Karpas 299 was enhanced by most anti-CD30 antibodies, it was inhibited by antibodies Ber-H2 and Ki-4. On the basis of the recognized epitopes, shedding seemed to depend on the availability of the cysteine-rich domains (CRD) 2 and 5 of the CD30 ectodomain. CRD2 and 5 have almost identical amino acid sequences and are localized distant from the TACE-targeted cleavage site. Soluble CD30, the product of this enzyme reaction, did not inhibit, but on the contrary, it stimulated CD30 shedding in a CRD2/5-dependent manner. This process could also be induced by CRD2/5-derived peptides but not by a CRD1-derived control peptide. This example of a product-activation was CD30 selective since other TACE substrates such as TNFR1 or TNF-alpha were not affected. These data suggest that CD30 shedding is stimulated by an elevated local availability of CRD2 or 5, possibly by forming a docking station for the releasing enzyme through substrate aggregation.

Metalloproteinase inhibition augments antitumor efficacy of the anti-CD30 immunotoxin Ki-3(scFv)-ETA? against human lymphomasin vivo

There is increasing evidence that the shedding of extracellular antigen domains impedes selective immunotherapy. One example is CD30, which is overexpressed on the surface of malignant lymphoma cells and has been identified as a promising target for antibody-based immunotherapy. However, CD30 is cleaved from the surface of target cells and the resulting soluble ectodomain (sCD30) is protecting the cells from antibody binding. Shedding can be inhibited by hydroxamate inhibitors of metalloproteinases such as BB-3644. We thus evaluated the influence of BB-3644 on the efficacy of the anti-CD30 single-chain immunotoxin Ki-3(scFv)-ETA'. In vitro, the addition of BB-3644 augmented the antitumor effect of Ki-3(scFv)-ETA' against Hodgkin-derived L540Cy cells by a factor of 2.75. Severe combined immunodeficiency (SCID) mice challenged with CD30-positive L540Cy cells were treated with the immunotoxin. One single nontoxic dose of BB-3644 increased the mean survival time of animals treated concomitantly with Ki-3(scFv)-ETA' to 93 days as compared with 35 days in the control (p = 0.0017). When BB-3644 was continuously delivered using subcutaneously implanted pumps, this effect was even more pronounced with no observed tumor growth in the animals within 200 days. Thus, concomitant application of metalloproteinase inhibitors might become clinically relevant in antibody-based immunotherapy against targets known to be shed from tumor cells.

Selection of antibody fragments specific for an alpha-helix region of acylphosphatase

The native state of common-type acylphosphatase (AcP) elicits two alpha-helices spanning residues 22-32 and 55-67 in the protein sequence. A peptide corresponding to the second alpha-helix (helix-2) of the protein was used to select phage antibodies consisting of a single chain fragment variable. The selection was performed in the presence of trifluoroethanol, a cosolvent known to induce the formation of helical structure in peptides and proteins. Phage scFv antibodies capable of binding the peptide specifically in a trifluoroethanol-induced alpha-helical conformation were isolated by affinity selection (biopanning). Some of these scFvs were also able to bind the native protein but not the peptide in a non-helical unstructured state. This indicates that the structural determinant recognized by the selected antibodies is the alpha-helical conformation of this specific region, rather than simply its amino acid sequence. This study shows that phage display libraries can be used to raise antibodies one can use as reagents able to target regions of a protein with a specific native-like secondary structure.