Experimental Hematology & Oncology

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is characterized by lymphocyte-predominant (LP) cells in a background of CD4+ CD57+ T-cells. These cells are normally present in the germinal center of lymphoid tissues. The cells rosetting LP cells are described to be PD-1 and BCL-6 positive, which are markers of T-follicular helper cells. This study was designed to address the question: are the CD57+ T cells in germinal centers of tonsil and NLPHL TFH cells? Immunohistochemistry was performed on tonsil and NLPHL. For tonsil, cells per germinal center and for NLPHL, the area around LP cells was counted. Cells rosetting LP cells were also determined. In addition, flowcytometry was performed on cell suspensions. Cells directly rosetting LP cells are positive for CD57 and/or for two markers of T-follicular helper (TFH) cells, PD-1 and BCL-6. We show that in both tonsil and NLPHL more than 90 % of CD57+ T-cells are also positive for PD-1, whereas roughly half of the PD-1+ T-cells are CD57+. CD57+ cells co-express BCL-6 in tonsil and in the rosetting cells of NLPHL. We conclude that CD57+ T-cells are TFH cells and form a subpopulation of TFH cells in tonsils and NLPHL.

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of relapsed/refractory B-cell malignancies. However, there is no data on the safety and efficacy of CAR T-cell therapy in patients with end stage renal disease (ESRD) requiring dialysis. In this report, we present two patients with DLBCL and ESRD who were successfully treated with different CAR T-cell products. Patient #1 is a 66 year-old woman with a history of HIV who was treated to complete response with axicabtagene ciloleucel with treatment complicated by grade 1 cytokine release syndrome (CRS) and grade 2 immune effector cell-associated neurolotoxicity syndrome (ICANS). Patient #2 is 52 year old woman whose ESRD was caused by ifosphamide toxicity and was treated to complete response with lisocabtagene maraleucel and did not experience either CRS or ICANS. Both patients received lymphodepletion chemotherapy with fludarabine and cyclophosphamide, which was dose-adjusted for ESRD with scheduled dialysis 12 h after each dose of lymphodepletion chemotherapy. Patients with DLBCL and ESRD can be safely administered both lymphodepletion chemotherapy and CAR T-cell therapy. Additionally, the fact that both patients achieved complete response to therapy suggests that CAR T-cell therapy should be strongly considered in patients with ESRD. Long-term follow up is needed to determine if therapy in this setting is of curative intent.

Cancer stem cells (CSCs) have been identified in multiple myeloma (MM) and are widely regarded as a key driver of MM initiation and progression. E-cadherin, in addition to its established role as a marker for epithelial-mesenchymal transition, also plays critical roles in controlling the aggressive behaviors of various tumor cells. Here, we show that depletion of E-cadherin in MM cells remarkably inhibited cell proliferation and cell cycle progression, in part through the decreased prosurvival CD138 and Bcl-2 and the inactivated Akt and MAPK pathways. CSC features, including the ability of the cells to form clonogenic colonies indicative of self-renewal and side population, were greatly suppressed upon the depletion of E-cadherin and subsequent loss of SOX9 stem-cell factor. We further provide evidence that SOX9 is a downstream target of E-cadherin-mediated CSC growth and self-renewal—ectopic re-expression of SOX9 in E-cadherin-depleted cells rescued its inhibitory effects on CSC-like properties and survival signaling. Collectively, our findings unveil a novel regulatory mechanism of MM CSCs via the E-cadherin/SOX9 axis, which could be important in understanding the long-term cell survival and outgrowth that leads to relapsed/refractory MM.

Dendritic cell (DC) vaccines induce specific immune responses that can selectively eliminate target cells. In recent years, many studies have been conducted to explore DC vaccination in the treatment of hematological malignancies, including acute myeloid leukemia and myelodysplastic syndromes, as well as other nonleukemia malignancies. There are at least two different strategies that use DCs to promote antitumor immunity: in situ vaccination and canonical vaccination. Monocyte-derived DCs (mo-DCs) and leukemia-derived DCs (DCleu) are the main types of DCs used in vaccines for AML and MDS thus far. Different cancer-related molecules such as peptides, recombinant proteins, apoptotic leukemic cells, whole tumor cells or lysates and DCs/DCleu containing a vaster antigenic repertoire with RNA electroporation, have been used as antigen sources to load DCs. To enhance DC vaccine efficacy, new strategies, such as combination with conventional chemotherapy, monospecific/bispecific antibodies and immune checkpoint-targeting therapies, have been explored. After a decade of trials and tribulations, much progress has been made and much promise has emerged in the field. In this review we summarize the recent advances in DC vaccine immunotherapy for AML/MDS as well as other nonleukemia malignancies.

Multiple myeloma is an incurable malignant disorder of mature B-cells that predominantly affects the elderly. The immunomodulatory drug (IMiD) thalidomide and its newer analogs demonstrate increased antitumor activity, and have had a positive impact on the natural history of multiple myeloma. Recent advances in the clinical application of these agents and in our understanding of their mechanism of action, and toxicity have made safer and smarter use of these drugs possible. This review discusses the available information regarding mechanisms of action, toxicity and clinical results on thalidomide, lenalidomide and pomalidomide in the therapy of multiple myeloma.

Cellular immunotherapy, particularly CAR-T cells, has shown potential in the improvement of outcomes in patients with refractory and recurrent malignancies of the blood. However, achieving sustainable long-term complete remission for blood cancer remains a challenge, with resistance and relapse being expected outcomes for many patients. Although many studies have attempted to clarify the mechanisms of CAR-T cell therapy failure, the mechanism remains unclear. In this article, we discuss and describe the current state of knowledge regarding these factors, which include elements that influence the CAR-T cell, cancer cells as a whole, and the microenvironment surrounding the tumor. In addition, we propose prospective approaches to overcome these obstacles in an effort to decrease recurrence rates and extend patient survival subsequent to CAR-T cell therapy.

Acute myeloid leukemia (AML) is a complex, heterogeneous malignant hematologic disease. Although multiple prognostic-related genes gave been explored in previous studies, there are still many genes whose prognostic value remains unclear. In this study, a total of 1532 AML patients from three GEO databases were included, five genes with potential prognostic value (DLC1, NF1B, DENND5B, TANC2 and ELAVL4) were screened by weighted gene co-expression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE). Based on this, we conducted survival analysis of the above five genes through the TCGA database and found that low level of DLC1 was detrimental to the long-term prognosis of AML patients. We also performed external validation in 48 AML patients from our medical center to analyze the impact of DLC1 level on prognosis. In conclusion, DLC1 may be a potential marker affecting the prognosis of AML, and its deficiency is associated with poor prognosis.