The expression of cell adhesion molecule 1 and its splicing variants in Sézary cells and cell lines from cutaneous T‐cell lymphoma

Cell adhesion molecule 1 expression in mycosis fungoides versus parapsoriasis versus inflammatory dermatosis: an immunohistochemical comparative study

Cell adhesion molecule 1 (CADM1) is one of the immunoglobulin super family adhesion molecules, that is proposed to contribute in the pathogenesis of various types of cutaneous T-cell lymphoma, including mycosis fungoides (MF). In this work, we decided to examine the immunohistochemical expression of CADM1 in MF specimens compared to premycotic parapsoriasis, benign inflammatory dermatosis and normal control skin specimens. 125 participants were enrolled (50 MF, 25 parapsoriasis, 25 inflammatory dermatosis, and 25 healthy controls). Patients were selected from the Outpatient Clinic of Dermatology and Venereology Department, Tanta University Hospitals. From all, 4 mm punch skin biopsies were taken and examined for CADM1 immunohistochemical expression. The current study revealed statistically significant upregulation of CADM1 expression in MF specimens in comparison to parapsoriasis, inflammatory dermatosis, and normal control specimens. Additionally, there was statistically significant positive correlation between CADM1 expression and progression of TNMB staging of MF disease. Therefore, it is possible to recommend CADM1 as a beneficial diagnostic immunohistochemical marker for differentiation between early stages of MF and both the premycotic parapsoriasis and benign inflammatory dermatosis. Moreover, it may be of value in early detection of neoplastic transformation of parapsoriasis as well as in assessment of MF progression.

mAb14, a Monoclonal Antibody against Cell Surface PCNA: A Potential Tool for Sezary Syndrome Diagnosis and Targeted Immunotherapy

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common types of primary cutaneous T-cell lymphoma (CTCL). Proliferating cell nuclear antigen (PCNA) is expressed on the cell surface of cancer cells (csPCNA), but not on normal cells. It functions as an immune checkpoint ligand by interacting with natural killer (NK) cells through the NK inhibitory receptor NKp44, leading to the inhibition of NK cytotoxicity. A monoclonal antibody (mAb14) was established to detect csPCNA on cancer cells and block their interaction with NKp44. In this study, three CTCL cell lines and peripheral blood mononuclear cells (PBMCs) from patients with SS and healthy donors were analyzed for csPCNA using mAb14, compared to monoclonal antibody PC10, against nuclear PCNA (nPCNA). The following assays were used: immunostaining, imaging flow cytometry, flow cytometry, cell sorting, cell cycle analysis, ELISA, and the NK-cell cytotoxic assay. mAb14 successfully detected PCNA on the membrane and in the cytoplasm of viable CTCL cell lines associated with the G2/M phase. In the Sézary PBMCs, csPCNA was expressed on lymphoma cells that had an atypical morphology and not on normal cells. Furthermore, it was not expressed on PBMCs from healthy donors. In the co-culture of peripheral blood NK (pNK) cells with CTCL lines, mAb14 increased the secretion of IFN-γ, indicating the reactivation of pNK activity. However, mAb14 did not enhance the cytotoxic activity of pNK cells against CTCL cell lines. The unique expression of csPCNA detected by mAb14 suggests that csPCNA and mAb14 may serve as a potential biomarker and tool, respectively, for detecting malignant cells in SS and possibly other CTCL variants.

Genome-wide identification of alternative splicing associated with histone deacetylase inhibitor in cutaneous T-cell lymphomas

Cutaneous T-cell lymphomas (CTCLs) are a kind of non-Hodgkin lymphoma that originates from skin, which is difficult to treat with traditional drugs. Human histone deacetylase inhibitors (HDACi) targeted therapy has become a promising treatment strategy in recent years, but some patients can develop resistance to the drug, leading to treatment failure. There are no public reports on whether alternative splicing (AS) and RNA binding proteins (RBP) affect the efficacy of targeted therapy. Using data from the Gene Expression Omnibus (GEO) database, we established a co-change network of AS events and RBP in CTCLs for the first time, and analyzed the potential regulatory effects of RBP on HDACi-related AS events. The dataset GSE132053, which contained the RNA sequence data for 17 HDACi samples, was downloaded and clean reads were aligned to the human GRCh38 genome by hierarchical indexing for spliced alignment of the transcripts, allowing four mismatches. Gene expression levels were evaluated using exons per million fragments mapped for each gene. Student’s t-tests were performed to evaluate the significance of changes in ratios for AS events, and regulated alternative splicing events (RASEs) were defined as events with p values less than 0.05. To sort the differentially expressed genes functional categories, Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were identified using the KOBAS 2.0 server. The regulatory mechanisms of the RASEs and RBPs were evaluated using Pearson’s correlation coefficient. Seven indirect events of HDACi resistance or sensitivity were identified: NIR_5151_RP11-977G19.10, NIR_4557_IRAG2, NIR_11870_SUMO1, NIR_5347_ING4, NIR_17935_DNAJC2, NIR_17974_CBLL1, and NIR_422_SLC50A1. The potential regulatory relationships between RBPs and HDACi-sensitive RASEs were also analyzed. LEPR and HNRNPAO significantly affected NIR_11870_SUMO1, suggesting a potential regulatory relationship. Additionally, CNN1 may regulate NIR_5347_ING4, CNOT3 may regulate NIR_17935_DNAJC2, and DQX1 and LENG9 may regulate NIR_422_SLC5A1. Overall, our findings establish a theoretical foundation for the precise targeted treatment of CTCLs with HDACi.

Trans-homophilic interaction of CADM1 promotes organ infiltration of T-cell lymphoma by adhesion to vascular endothelium

The initial step of organ infiltration of malignant cells is the interaction with host vascular endothelial cells, which is often mediated by specific combinations of cell adhesion molecules. Cell adhesion molecule 1 (CADM1) is overexpressed in adult T-cell leukemia/lymphoma (ATL) and provides a cell-surface diagnostic marker. CADM1 promotes the adhesion of ATL cells to vascular endothelial cells and multiple organ infiltration in mice. However, its binding partner on host cells has not yet been identified. In this study, we show that CADM1 promotes transendothelial migration of ATL cells in addition to the adhesion to vascular endothelial cells. Moreover, CADM1 enhances liver infiltration of mouse T-cell lymphoma cells, EL4, after tail vein injection, whereas a CADM1 mutant lacking adhesive activity did not. Among the known CADM1-binding proteins expressed in primary endothelial cells, only CADM1 and CADM4 could induce morphological extension of ATL cells when plated onto glass coated with these proteins. Furthermore, CADM1-mediated liver infiltration of EL4 cells was canceled in conventional and vascular endothelium-specific Cadm1 knockout mice, whereas it was not canceled in Cadm4 knockout mice. These results suggest that CADM1 on host vascular endothelial cells is required for organ infiltration of ATL and other T-cell lymphomas expressing CADM1.

Diagnosis and prognostic stratification of cutaneous lymphoma

Primary cutaneous lymphomas are a heterogenous group of non-Hodgkin's lymphoma of both T/natural killer-cell and B-cell origin and defined to primarily present in the skin without extracutaneous involvement at diagnosis. In contrast to nodal non-Hodgkin's lymphoma, cutaneous T-cell lymphomas (CTCL) are more generally seen than cutaneous B-cell lymphomas (CBCL). CTCL and CBCL have various subtypes and each subtype has specifically characteristic clinical, pathological, and prognostic features. The diagnostic methods and staging evaluation of cutaneous lymphomas is mostly common in various guidelines created by professional societies. The diagnosis is made comprehensively based on clinical, pathological, laboratory, radiological, and genetic findings. On the other hand, definite prognostic stratification has not been completely established yet in most cutaneous lymphomas. This article focuses on the general and novel diagnostic methods and the current findings about prognostic factors and stratification in cutaneous lymphomas.

Cell Adhesion Molecule 1 (CADM1) Is an Independent Prognostic Factor in Patients with Cutaneous Squamous Cell Carcinoma

Cell adhesion molecular 1 (CADM1) is a multifunctional cell adhesion molecule belonging to the immunoglobulin superfamily, which suppresses malignant solid tumor development. However, the correlation between CADM1 expression and prognosis in cutaneous squamous cell carcinoma (cSCC) patients remains unclear. In a retrospective analysis of 88 patients diagnosed with cSCC at our institution between January 2006 and December 2016, the degree of CADM1 expression in tumor cells was evaluated by immunostaining. Fifty-five and 33 patients had tumors with high and low CADM1 expression, respectively. Low CADM1 expression on the tumor was associated with poor differentiation, whereas the Kaplan–Meier curve and log-lank test indicated a favorable prognosis with high CADM1 expression. Multivariate analysis excluding the effect of the degree of differentiation and clinical stages showed that the hazard ratio (HR) of survival was significantly increased with low CADM1 expression. Thus, CADM1 expression is an independent prognostic factor for cSCC patients.

The Role of Cell Adhesion Molecule 1 (CADM1) in Cutaneous Malignancies

Cell adhesion ability is one of the components to establish cell organization and shows a great contribution to human body construction consisting of various types of cells mixture to orchestrate tissue specific function. The cell adhesion molecule 1 (CADM1) is a molecule of cell adhesion with multiple functions and has been identified as a tumor suppressor gene. CADM1 has multifunctions on the pathogenesis of malignancies, and other normal cells such as immune cells. However, little is known about the function of CADM1 on cutaneous cells and cutaneous malignancies. CADM1 plays an important role in connecting cells with each other, contacting cells to deliver their signal, and acting as a scaffolding molecule for other immune cells to develop their immune responses. A limited number of studies reveal the contribution of CADM1 on the development of cutaneous malignancies. Solid cutaneous malignancies, such as cutaneous squamous cell carcinoma and malignant melanoma, reduce their CADM1 expression to promote the invasion and metastasis of the tumor. On the contrary to these cutaneous solid tumors except for Merkel cell carcinoma, cutaneous lymphomas, such as adult-T cell leukemia/lymphoma, mycosis fungoides, and Sézary syndrome, increase their CADM1 expression for the development of tumor environment. Based on the role of CADM1 in the etiology of tumor development, the theory of CADM1 contribution will desirably be applied to skin tumors according to other organ malignancies, however, the characteristics of skin as a multicomponent peripheral organ should be kept in mind to conclude their prognoses.