Prognostic significance of activation and differentiation antigen expression in B-cell non-Hodgkin's lymphoma

CD98hc promotes drug resistance in extranodal natural killer/T cell lymphoma through tumor cell-derived small extracellular vesicles

Extranodal natural killer/T cell lymphoma (ENKTL) shows a high rate of recurrence after chemoradiotherapy. Drug resistance can be mediated by the cargo of small extracellular vesicles (sEVs). Here, we show that high abundance of the transmembrane glycoprotein CD98hc in tumor cells and serum sEVs was associated with ENKTL progression and drug resistance. Mechanistically, PEGylated-asparaginase (PEG-asp) treatment, a common therapy against ENKTL, promoted the translocation of the transcription factor ATF4 to the nucleus, where it was stabilized by USP1 and subsequently increased CD98hc expression. CD98hc delivered in tumor cell-derived sEVs increased tumor cell proliferation and drug resistance in a cultured human NK lymphoma cell line, animal models, and samples from patients with refractory/relapse ENKTL. Moreover, inhibiting both USP1 and EV secretion synergistically enhanced the cytotoxicity of PEG-asp. These data suggest that targeting CD98hc in the treatment of ENKTL may be beneficial in overcoming drug resistance.

A novel SLC3A2-targeting antibody-drug conjugate exerts potent antitumor efficacy in head and neck squamous cell cancer

The development of innovative therapeutic strategies for head and neck squamous cell carcinoma (HNSCC) is a critical medical requirement. Antibody-drug conjugates (ADC) targeting tumor-specific surface antigens have demonstrated clinical effectiveness in treating hematologic and solid malignancies. Our investigation revealed high expression levels of SLC3A2 in HNSCC tissue and cell lines. This study aimed to develop a novel anti-SLC3A2 ADC and assess its antitumor effects on HNSCC both in vitro and in vivo. This study developed a potent anti-SLC3A2 ADC (19G4-MMAE) and systematically investigated its drug delivery potential and antitumor efficacy in preclinical models. This study revealed that 19G4-MMAE exhibited specific binding to SLC3A2 and effectively targeted lysosomes. Moreover, 19G4-MMAE induced a significant accumulation of reactive oxygen species (ROS) and apoptosis in SLC3A2-positive HNSCC cells. The compound demonstrated potent antitumor effects derived from MMAE against SLC3A2-expressing HNSCC in preclinical models, displaying a favorable safety profile. These findings suggest that targeting SLC3A2 with an anti-SLC3A2 ADC could be a promising therapeutic approach for treating HNSCC patients.

Design of a surrogate Anticalin protein directed against CD98hc for preclinical studies in mice

The human CD98 heavy chain (CD98hc) offers a promising biomedical target both for tumor therapy and for drug delivery to the brain. We have previously developed a cognate Anticalin protein with picomolar affinity and demonstrated its effectiveness in a xenograft animal model. Due to the lack of cross‐reactivity with the murine ortholog, we now report the development and X‐ray structural analysis of an Anticalin with high affinity toward CD98hc from mouse. This binding protein recognizes the same protruding epitope loop—despite distinct structure—in the membrane receptor ectodomain as the Anticalin selected against human CD98hc. Thus, this surrogate Anticalin should be useful for the preclinical assessment of CD98hc targeting in vivo and support the translational development for medical application in humans.

PDB Code(s): 6SUA;

Development of a high affinity Anticalin® directed against human CD98hc for theranostic applications

Enhanced amino acid supply and dysregulated integrin signaling constitute two hallmarks of cancer and are pivotal for metastatic transformation of cells. In line with its function at the crossroads of both processes, overexpression of CD98hc is clinically observed in various cancer malignancies, thus rendering it a promising tumor target.

Methods: We describe the development of Anticalin proteins based on the lipocalin 2 (Lcn2) scaffold against the human CD98hc ectodomain (hCD98hcED) using directed evolution and protein design. X-ray structural analysis was performed to identify the epitope recognized by the lead Anticalin candidate. The Anticalin - with a tuned plasma half-life using PASylation^® technology - was labeled with ⁸⁹Zr and investigated by positron emission tomography (PET) of CD98-positive tumor xenograft mice.

Results: The Anticalin P3D11 binds CD98hc with picomolar affinity and recognizes a protruding loop structure surrounded by several glycosylation sites within the solvent exposed membrane-distal part of the hCD98hcED. In vitro studies revealed specific binding activity of the Anticalin towards various CD98hc-expressing human tumor cell lines, suggesting broader applicability in cancer research. PET/CT imaging of mice bearing human prostate carcinoma xenografts using the optimized and ⁸⁹Zr-labeled Anticalin demonstrated strong and specific tracer accumulation (8.6 ± 1.1 %ID/g) as well as a favorable tumor-to-blood ratio of 11.8.

Conclusion: Our findings provide a first proof of concept to exploit CD98hc for non-invasive biomedical imaging. The novel Anticalin-based αhCD98hc radiopharmaceutical constitutes a promising tool for preclinical and, potentially, clinical applications in oncology.

Ubiquitylation of CD98 limits cell proliferation and clonal expansion

CD98 heavy chain (SLC3A2) facilitates lymphocyte clonal expansion that enables adaptive immunity; however, increased expression of CD98 is also a feature of both lymphomas and leukemias and represents a potential therapeutic target in these diseases. CD98 is transcriptionally regulated and ectopic expression of the membrane-associated RING-CH (MARCH) E3 ubiquitin ligases MARCH1 or MARCH8 leads to ubiquitylation and lysosomal degradation of CD98. Here, we examined the potential role of ubiquitylation in regulating CD98 expression and cell proliferation. We report that blocking ubiquitylation by use of a catalytically inactive MARCH or by creating a ubiquitylation-resistant CD98 mutant, prevents MARCH-induced CD98 downregulation in HeLa cells. March1-null T cells display increased CD98 expression. Similarly, T cells expressing ubiquitylation-resistant CD98 manifest increased proliferation in vitro and clonal expansion in vivo. Thus, ubiquitylation and the resulting downregulation of CD98 can limit cell proliferation and clonal expansion.

Genetic variations in SLC3A2/CD98 gene as prognosis predictors in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is characterized by poor prognosis and only a few molecular markers may be potentially used to predict the risk of progression. This study aims to assess the effects of single nucleotide polymorphisms (SNPs) in the CD98 gene on prognosis of NSCLC patients. We genotyped three potential functional SNPs in CD98 gene using Sequenom iPLEX genotyping system in a cohort of 482 NSCLC patients. Multivariate cox proportional hazards model and Kaplan-Meier curve were used for the survival analysis. The variant-containing genotypes of rs1059292 in 5'-flanking region of CD98 gene were significantly associated with an increased risk of death in the multivariate analysis (Hazard ratio [HR], 1.49; 95% confidence interval [95% CI]: 1.04-2.14 in a dominant model). In stratified analysis, the association remained significant in patients with poor differentiation (HR=1.81, 95% CI=1.01-3.25). In addition, rs1059292 also showed a borderline significant association with T stage (OR=1.49; 95% CI: 0.96-2.35) and N stage (OR=1.53; 95% CI: 0.98-2.39). Functional analysis demonstrated that variant genotype of SNP rs1059292 significantly enhanced the transcription activity of CD98 gene promoter. Our data suggest that genetic variation of rs1059292 in CD98 gene may affect clinical outcome of NSCLC in Chinese population.

CD98 at the crossroads of adaptive immunity and cancer

Adaptive immunity, a vertebrate specialization, adds memory and exquisite specificity to the basic innate immune responses present in invertebrates while conserving metabolic resources. In adaptive immunity, antigenic challenge requires extremely rapid proliferation of rare antigen-specific lymphocytes to produce large, clonally expanded effector populations that neutralize pathogens. Rapid proliferation and resulting clonal expansion are dependent on CD98, a protein whose well-conserved orthologs appear restricted to vertebrates. Thus, CD98 supports lymphocyte clonal expansion to enable protective adaptive immunity, an advantage that could account for the presence of CD98 in vertebrates. CD98 supports lymphocyte clonal expansion by amplifying integrin signals that enable proliferation and prevent apoptosis. These integrin-dependent signals can also provoke cancer development and invasion, anchorage-independence and the rapid proliferation of tumor cells. CD98 is highly expressed in many cancers and contributes to formation of tumors in experimental models. Strikingly, vertebrates, which possess highly conserved CD98 proteins, CD98-binding integrins and adaptive immunity, also display propensity towards invasive and metastatic tumors. In this Commentary, we review the roles of CD98 in lymphocyte biology and cancer. We suggest that the CD98 amplification of integrin signaling in adaptive immunity provides survival benefits to vertebrates, which, in turn, bear the price of increased susceptibility to cancer.

Prognostic value of bcl-6, CD10 and CD38 immunoreactivity in stage I-II gastric lymphomas: identification of a subset of CD10+ large B-cell lymphomas with a favorable outcome

bcl-6, CD10 and CD38 are useful markers for identifying 2 molecularly and prognostically distinct profiles of diffuse large B-cell lymphomas (LCLs), defined as germinal-center B-like and activated B-like. We investigated the prognostic role of bcl-6, CD10 and CD38 immunoreactivity in 102 gastrectomized patients with primary gastric lymphomas (PGLs). There were 41 low-grade marginal zone lymphomas of MALT-type (LGML) and 61 diffuse large B-cell lymphomas with (DLCLMLs; n = 31) or without (DLCLs; n = 30) an LGML component. bcl-6, CD10 and CD38 were significantly more commonly expressed in DLCL or DLCML as compared with LGML (50% vs. 48% vs. 17%, p = 0.0002 for bcl-6; 27% vs. 26% vs. 0%, p = 0.0004 for CD10; 45% vs. 48% vs. 13%, p = 0.0005 for CD38, respectively). CD10 immunoreactivity was independently associated with a better survival in diffuse LCL patients (5-year overall survival: 88% +/- 8% vs. 66% +/- 7%; p = 0.04); bcl-6 or CD38 immunoreactivities did not disclose any prognostic implication. Age, presence of LGML component, lactic dehydrogenase serum levels and use of chemotherapy were additional independent prognostic factors. We conclude that CD10 immunoreactivity assessment could be a clear, easy-to-interpret and reliable prognostic factor in PGL. Accordingly, patients with CD10(+) gastric large B-cell lymphomas may be at reduced risk and eligible for clinical trials evaluating more conservative therapeutic options.

Epstein-Barr virus (EBV)-positive pyothorax-associated lymphoma (PAL): chromosomal integration of EBV in a novel CD2-positive PAL B-cell line

Pyothorax-associated lymphoma (PAL) is a clinico-pathological entity arising in the pleural cavity of patients with long-standing inflammatory pyothorax. PAL is closely associated with Epstein-Barr virus (EBV), but how this virus contributes to the development of the lymphoma is unknown. We have successfully obtained a novel EBV-infected PAL cell line, designated Pal-1. The cell line and its source coexpressed CD2 and CD20 molecules, but other representative B- and T-cell markers such as CD1, CD3, CD5, CD7, CD10 and CD19 were not found. The B-cell origin of Pal-1 cells was proven by rearrangement of the immunoglobulin heavy- and light-chain genes without rearranged T-cell receptor genes. Both the cell line and primary tumour cells carried monoclonal EBV genome. Although EBV genome is known to be maintained as circular extrachromosomal DNA, neither circular nor linear extrachromosomal EBV DNA was detectable in Pal-1 cells by in situ lysis gel analysis. Fluorescence in situ hybridization demonstrated viral integration at a marker chromosome mostly consisting of the centromere region of chromosome 1. The viral integration event may enhance a chromosomal instability at the insertion site. This cell line represents the first example of EBV integration in PAL and could enable the study of the potential role of integrated viral infection in the development of PAL as well as mechanism of the aberrant phenotype expression.

Correlation and prognostic value of serum soluble ICAM-1, beta-2 microglobulin, and IL-2alphaR levels in non-Hodgkin's lymphoma

Serum levels of sICAM-1, sIL-2alphaR, and beta-2 microglobulin were measured in 63 patients with non-Hodgkin's lymphoma (NHL). The correlation between these serum markers as well as their relationship with NHL features and disease outcome were analyzed. Although in high-grade NHL sICAM-1 levels correlated with tumor mass, no correlation was found between sICAM-1 levels and tumor burden in low-grade NHL. When compared with sICAM-1 and beta-2 microglobulin, sIL-2alphaR showed the strongest correlation with the tumor burden. However, in multivariate analysis, including serum markers employed as continuous variables, the only parameteres which entered the regression model were beta-2 microglobulin (p=0.012) and sICAM-1 (p=0.019). In a dichotomized model, beta-2 microglobulin, aggressive histology, sICAM-1, age and number of nodal involved sites were found to be prognostically significant. Finally, by combining sICAM-1 and beta-2 microglobulin serum levels, a simple prognostic model useful for NHL was obtained.

Levels of CAF7 (CD98) expression correlate with the complete remission duration in childhood acute leukemia

The levels of expression of the activation antigen CD98 were studied by mAB CAF7 in 51 newly diagnosed consecutive cases of childhood acute lymphoblastic leukemia aged from 1 to 13 years. The mean follow-up was 8 months. A wide range of CAF7 expression was observed, the highest mean fluorescence intensity exceeding the lowest by 20 times. No correlation was revealed between CAF7 cell surface density on the one hand and sex, age, WBC, platelet count, LDH level, FAB groups and immunophenotypes on the other. A positive association between the levels of CAF7 expression and the complete remission (CR) duration was observed. The group of CAF7(low) patients had a significantly shorter CR duration compared to the CAF7(intermediate) and CAF7(high) cases (P=0.0099). Half of the CAF7(low) patients did not respond to the induction therapy and failed to achieve remission. These correlations were clearly marked in common ALL (cALL), which was usually considered to have a favorable outcome. All CAF7(low) cALL cases had a significantly shorter CR duration (P=0.027). Thus CAF7 appears to provide additional information on the biological characteristics of childhood ALL and may have prognostic value regarding the response to therapy and remission duration.

The usefulness of cell surface markers in predicting the prognosis of non-Hodgkin's lymphomas

The Working Formulation for classification of non-Hodgkin's lymphomas provides useful prognostic information. Since this scheme was published in 1982, many studies have investigated the prognostic significance of various cell surface markers in lymphoma cases. This article reviews the value of distinguishing T cells from B cells, CD5+ B cells, immunoglobulin light chain types, proliferation antigens such as Ki 67, other markers of B-cell differentiation, and chromosomal anomalies. Each of these contributes some further prognostic significance to that already determined by the Working Formulation.

Immunohistochemical, molecular, and cytogenetic analysis of a consecutive series of 20 peripheral T-cell lymphomas and lymphomas of uncertain lineage, including 12 Ki-1 positive lymphomas

Although several independent series of non-Hodgkin's lymphomas (NHLs) have been subjected to cytogenetic studies or analyses of lineages by assaying for clonal immunophenotypes and clonal rearrangements affecting immunoglobulin (IG) and T-cell receptor (TCR) genes, no published reports exist of series of non-B-cell NHLs on which cytogenetic, immunohistochemical, and IG and TCR gene rearrangement studies have been undertaken together. Among 343 NHLs ascertained prospectively between January 1984 and December 1988 at the Memorial Sloan-Kettering Cancer Center, 278 cases with clonal chromosome abnormalities were identified. Of the latter, 20 were non-B-cell NHLs, which in turn comprised 15 peripheral T-cell lymphomas (PTCLs) and 5 lymphomas of uncertain lineage (LULs). The LULs either were biogenotypic, had discordant immunophenotype and immunogenotype, or showed no evidence of B-cell, T-cell, or histiocytic derivation. Of the 15 PTCLs, eight expressed the Ki-1 antigen and four of these had translocations involving the band 5q35 [t(5q35)]. Of the five LULs, four expressed the Ki-1 antigen and one of these had a translocation involving band 5q35. Previous studies have associated t(5q35) with Ki-1 positive NHLs characterized histologically by a pleomorphic diffuse large cell morphology. In our series of 12 Ki-positive non-B-cell NHLs, five (42%) had a 5q35 translocation. They were histologically indistinguishable from the subset without the translocation. The frequent lineage uncertainty exhibited by Ki-1 positive NHLs of similar histology and cytogenetic abnormalities suggests their derivation from an early uncommitted lymphoid cells.