Distinct Chemokine Receptor Expression Profiles in De Novo DLBCL,Transformed Follicular Lymphoma,Richter’s Trans-Formed DLBCL and Germinal Center B-Cells

Chemokine receptors and their ligands have been identified as playing an important role in the development of diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, and Richter syndrome (RS). Our aim was to investigate the different expression profiles in de novo DLBCL, transformed follicular lymphoma (tFL), and RS. Here, we profiled the mRNA expression levels of 18 chemokine receptors (CCR1–CCR9, CXCR1–CXCR7, CX3CR1 and XCR1) using RQ-PCR, as well as immunohistochemistry of seven chemokine receptors (CCR1, CCR4–CCR8 and CXCR2) in RS, de novo DLBCL, and tFL biopsy-derived tissues. Tonsil-derived germinal center B-cells (GC-B) served as non-neoplastic controls. The chemokine receptor expression profiles of de novo DLBCL and tFL substantially differed from those of GC-B, with at least 5-fold higher expression of 15 out of the 18 investigated chemokine receptors (CCR1–CCR9, CXCR1, CXCR2, CXCR6, CXCR7, CX3CR1 and XCR1) in these lymphoma subtypes. Interestingly, the de novo DLBCL and tFL exhibited at least 22-fold higher expression of CCR1, CCR5, CCR8, and CXCR6 compared with RS, whereas no significant difference in chemokine receptor expression profile was detected when comparing de novo DLBCL with tFL. Furthermore, in de novo DLBCL and tFLs, a high expression of CCR7 was associated with a poor overall survival in our study cohort, as well as in an independent patient cohort. Our data indicate that the chemokine receptor expression profile of RS differs substantially from that of de novo DLBCL and tFL. Thus, these multiple dysregulated chemokine receptors could represent novel clinical markers as diagnostic and prognostic tools. Moreover, this study highlights the relevance of chemokine signaling crosstalk in the tumor microenvironment of aggressive lymphomas.     

Sensitivity of Cutaneous T-Cell Lymphoma Cells to the Mcl-1 Inhibitor S63845 Correlates with the Lack of Bcl-w Expression

Long-term, curative treatment of cutaneous T-cell lymphomas (CTCL) remains a major challenge. Therapy resistance is often based on apoptosis deficiency, and may depend on antiapoptotic Bcl-2 proteins, such as Bcl-2, Bcl-x_L, Bcl-w and Mcl-1. For their targeting, several antagonists have been generated, which mimic the Bcl-2 homology domain 3 (BH3 mimetics). As dysregulation and overexpression of Mcl-1 has been reported in CTCL, the use of Mcl-1 inhibitors appears as an attractive strategy. Here, we investigated the effects of the selective Mcl-1 inhibitor {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845 in a series of four CTCL cell lines, in comparison to ABT-263 and ABT-737 (inhibitors of Bcl-2, Bcl-x_L and Bcl-w). In two cell lines (HH, HuT-78), {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845 resulted in significant apoptosis induction, decrease in cell viability, loss of mitochondrial membrane potential and caspase activation, while two other cell lines (MyLa, SeAx) remained completely resistant. An inverse correlation was found, as {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845-resistant cells were highly sensitive to ABT-263/-737, and {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845-sensitive cells showed only moderate sensitivity to ABTs. Combinations of {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845 and ABT-263 partially yielded synergistic effects. As concerning Bcl-2 protein expression, weaker Mcl-1 expression was found in {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845-resistant MyLa and SeAx, while for Bcl-2 and Bcl-x_L, the lowest expression was found in the highly sensitive cell line HH. The most striking difference between {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845-resistant and -sensitive cells was identified for Bcl-w, which was exclusively expressed in {"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540"}}S63845-resistant cells. Thus, CTCL may be efficiently targeted by BH3 mimetics, providing the right target is preselected, and Bcl-w expression may serve as a suitable marker.     

Canine B Cell Lymphoma- and Leukemia-Derived Extracellular Vesicles Moderate Differentiation and Cytokine Production of T and B Cells In Vitro

Extracellular vesicles (EVs) are formed in physiological and pathological conditions by almost all mammalian cells. They are known as submicron “molecules” that transport and horizontally transfer their cargo from maternal cells to donor cells. Moreover, cancer cells produce tumor-derived EVs (TEVs), which are present in blood of patients with solid tumors and those with hematological malignancies. Their role in evading immune system surveillance and induction of immunosuppression in hematological cancer is limited. According to the authors’ best knowledge, there is no information about the impact of TEVs from canine lymphoma (CLBL-1) and leukemia (CLB70) on lymphocytes isolated from peripheral blood mononuclear cells (PBMCs). In conclusion, we demonstrate in in vitro experiments that CLBL-1 EVs and CLB70 EVs are effectively taken up by T and B lymphocytes. TEVs decrease the percentage of B lymphocytes and increase that of T lymphocytes, and change T cells’ phenotype into the effector memory (EM) or terminally differentiated effector memory (TEMRA) subtype after in vitro co-culturing. Moreover, CLBL70 EVs have pro-tumorogenic properties by inhibiting the production of CD8⁺IL-17⁺ cells.     

Anti-Angiogenic Therapy in ALK Rearranged Non-Small Cell Lung Cancer (NSCLC)

The management of advanced lung cancer has been transformed with the identification of targetable oncogenic driver alterations. This includes anaplastic lymphoma kinase (ALK) gene rearrangements. ALK tyrosine kinase inhibitors (TKI) are established first-line treatment options in advanced ALK rearranged non-small cell lung cancer (NSCLC), with several next-generation ALK TKIs (alectinib, brigatinib, ensartinib and lorlatinib) demonstrating survival benefit compared with the first-generation ALK TKI crizotinib. Still, despite high objective response rates and durable progression-free survival, drug resistance inevitably ensues, and treatment options beyond ALK TKI are predominantly limited to cytotoxic chemotherapy. Anti-angiogenic therapy targeting the vascular endothelial growth factor (VEGF) signaling pathway has shown efficacy in combination with platinum-doublet chemotherapy in advanced NSCLC without a driver alteration, and with EGFR TKI in advanced EGFR mutated NSCLC. The role for anti-angiogenic therapy in ALK rearranged NSCLC, however, remains to be elucidated. This review will discuss the pre-clinical rationale, clinical trial evidence to date, and future directions to evaluate anti-angiogenic therapy in ALK rearranged NSCLC.     

Micro-RNAs in Response to Active Forms of Vitamin D3 in Human Leukemia and Lymphoma Cells

Non-coding micro-RNA (miRNAs) regulate the protein expression responsible for cell growth and proliferation. miRNAs also play a role in a cancer cells’ response to drug treatment. Knowing that leukemia and lymphoma cells show different responses to active forms of vitamin D₃, we decided to investigate the role of selected miRNA molecules and regulated proteins, analyzing if there is a correlation between the selected miRNAs and regulated proteins in response to two active forms of vitamin D₃, calcitriol and tacalcitol. A total of nine human cell lines were analyzed: five leukemias: MV-4-1, Thp-1, HL-60, K562, and KG-1; and four lymphomas: Raji, Daudi, Jurkat, and U2932. We selected five miRNA molecules—miR-27b, miR-32, miR-125b, miR-181a, and miR-181b—and the proteins regulated by these molecules, namely, CYP24A1, Bak1, Bim, p21, p27, p53, and NF-kB. The results showed that the level of selected miRNAs correlates with the level of proteins, especially p27, Bak1, NFκB, and CYP24A1, and miR-27b and miR-125b could be responsible for the anticancer activity of active forms of vitamin D₃ in human leukemia and lymphoma.     

Molecular Aspects of Resistance to Immunotherapies—Advances in Understanding and Management of Diffuse Large B-Cell Lymphoma

Despite the unquestionable success achieved by rituximab-based regimens in the management of diffuse large B-cell lymphoma (DLBCL), the high incidence of relapsed/refractory disease still remains a challenge. The widespread clinical use of chemo-immunotherapy demonstrated that it invariably leads to the induction of resistance; however, the molecular mechanisms underlying this phenomenon remain unclear. Rituximab-mediated therapeutic effect primarily relies on complement-dependent cytotoxicity and antibody-dependent cell cytotoxicity, and their outcome is often compromised following the development of resistance. Factors involved include inherent genetic characteristics and rituximab-induced changes in effectors cells, the role of ligand/receptor interactions between target and effector cells, and the tumor microenvironment. This review focuses on summarizing the emerging advances in the understanding of the molecular basis responsible for the resistance induced by various forms of immunotherapy used in DLBCL. We outline available models of resistance and delineate solutions that may improve the efficacy of standard therapeutic protocols, which might be essential for the rational design of novel therapeutic regimens.     

Identification of Recurrent Mutations in the microRNA-Binding Sites of B-Cell Lymphoma-Associated Genes in Follicular Lymphoma

Follicular lymphoma (FL) is a common indolent B-cell lymphoma that can transform into the more aggressive transformed FL (tFL). However, the molecular process driving this transformation is uncertain. In this work, we aimed to identify microRNA (miRNA)-binding sites recurrently mutated in follicular lymphoma patients, as well as in transformed FL patients. Using whole-genome sequencing data from FL tumors, we discovered 544 mutations located in bioinformatically predicted microRNA-binding sites. We then studied these specific regions using targeted sequencing in a cohort of 55 FL patients, found 16 recurrent mutations, and identified a further 69 variants. After filtering for QC, we identified 21 genes with mutated miRNA-binding sites that were also enriched for B-cell-associated genes by Gene Ontology. Over 40% of mutations identified in these genes were present exclusively in tFL patients. We validated the predicted miRNA-binding sites of five of the genes by luciferase assay and demonstrated that the identified mutations in BCL2 and EZH2 genes impaired the binding efficiency of miR-5008 and miR-144 and regulated the endogenous levels of messenger RNA (mRNA).