title: Anti-Apoptotic Effects of Lentiviral Vector Transduction Promote Increased Rituximab Tolerance in Cancerous B-Cells.
abstract: Diffuse large B-cell lymphoma (DLBCL) is characterized by great genetic and clinical heterogeneity which complicates prognostic prediction and influences treatment efficacy. The most common regimen, R-CHOP, consists of a combination of anthracycline- and immuno-based drugs including Rituximab. It remains elusive how and to which extent genetic variability impacts the response and potential tolerance to R-CHOP. Hence, an improved understanding of mechanisms leading to drug tolerance in B-cells is crucial, and modelling by genetic intervention directly in B-cells is fundamental in such investigations. Lentivirus-based gene vectors are widely used gene vehicles, which in B-cells are an attractive alternative to potentially toxic transfection-based methodologies. Here, we investigate the use of VSV-G-pseudotyped lentiviral vectors in B-cells for exploring the impact of microRNAs on tolerance to Rituximab. Notably, we find that robust lentiviral transduction of cancerous B-cell lines markedly and specifically enhances the resistance of transduced germinal center B-cells (GCBs) to Rituximab. Although Rituximab works partially through complement-mediated cell lysis, increased tolerance is not achieved through effects of lentiviral transduction on cell death mediated by complement. Rather, reduced levels of PARP1 and persistent high levels of CD43 in Rituximab-treated GCBs demonstrate anti-apoptotic effects of lentiviral transduction that may interfere with the outcome and interpretation of Rituximab tolerance studies. Our findings stress that caution should be exercised exploiting lentiviral vectors in studies of tolerance to therapeutics in DLBCL. Importantly, however, we demonstrate the feasibility of using the lentiviral gene delivery platform in studies addressing the impact of specific microRNAs on Rituximab responsiveness.
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Benyamin
authors.initials: B
authors.lastname: Ranjbar
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Louise Bechmann
authors.initials: LB
authors.lastname: Krogh
authors.affiliation: Department of Hematology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Maria Bach
authors.initials: MB
authors.lastname: Laursen
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Maria Nascimento
authors.initials: MN
authors.lastname: Primo
authors.affiliation: Department of Hematology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Sara Correia
authors.initials: SC
authors.lastname: Marques
authors.affiliation: Department of Hematology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Karen
authors.initials: K
authors.lastname: Dybkær
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Jacob Giehm
authors.initials: JG
authors.lastname: Mikkelsen
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D001402:B-Lymphocytes / Q000187:drug effects*; D045744:Cell Line, Tumor; D005822:Genetic Vectors; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000473:pathology*; D000069283:Rituximab / Q000627:therapeutic use*; D014161:Transduction, Genetic
chemical_list: D000970:Antineoplastic Agents; D000069283:Rituximab