Stromal cells engineered to express T cell factors induce robust CLL cell proliferation in vitro and in PDX co-transplantations allowing the identification of RAF inhibitors as anti-proliferative drugs

• Published in: Leukemia Vol. 38; no. 8; pp. 1699 - 1711
• Main Authors: Hoferkova, Eva, Seda, Vaclav, Kadakova, Sona, Verner, Jan, Loja, Tomas, Matulova, Kvetoslava, Skuhrova Francova, Hana, Ondrouskova, Eva, Filip, Daniel, Blavet, Nicolas, Boudny, Miroslav, Mladonicka Pavlasova, Gabriela, Vecera, Josef, Ondrisova, Laura, Pavelkova, Petra, Hlavac, Krystof, Kostalova, Lenka, Michaelou, Androniki, Pospisilova, Sarka, Dorazilova, Jana, Chochola, Vaclav, Jaros, Josef, Doubek, Michael, Jarosova, Marie, Hampl, Ales, Vojtova, Lucy, Kren, Leos, Mayer, Jiri, Mraz, Marek
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2024; Nature Publishing Group
• Subjects: 13; 13/107; 13/21; 13/95; 631/67/1990/283/1895; 631/67/327; Allografts; Animals; Cancer Research; CD40 Ligand - genetics; CD40 Ligand - metabolism; CD40L protein; Cell culture; Cell growth; Cell Proliferation; Chronic lymphocytic leukemia; Coculture Techniques; Critical Care Medicine; Culture; Drug screening; E2F protein; Gene expression; Hematology; Humans; Immunosuppressive agents; Inhibitors; Intensive; Interleukin 21; Interleukins - genetics; Interleukins - metabolism; Internal Medicine; Leukemia; Leukemia, Lymphocytic, Chronic, B-Cell - drug therapy; Leukemia, Lymphocytic, Chronic, B-Cell - genetics; Leukemia, Lymphocytic, Chronic, B-Cell - pathology; Lymph nodes; Lymphocytes; Lymphocytes T; Medicine; Medicine & Public Health; Mice; Myc protein; NF-κB protein; Oncology; Protein Kinase Inhibitors - pharmacology; Raf protein; Robustness; Stromal cells; Stromal Cells - metabolism; Stromal Cells - pathology; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; Xenograft Model Antitumor Assays; Xenotransplantation
• ISSN: 0887-6924; 1476-5551; 1476-5551
• DOI: 10.1038/s41375-024-02284-w

Several in vitro models have been developed to mimic chronic lymphocytic leukemia (CLL) proliferation in immune niches; however, they typically do not induce robust proliferation. We prepared a novel model based on mimicking T-cell signals in vitro and in patient-derived xenografts (PDXs). Six supportive cell lines were prepared by engineering HS5 stromal cells with stable expression of human CD40L, IL4, IL21, and their combinations. Co-culture with HS5 expressing CD40L and IL4 in combination led to mild CLL cell proliferation (median 7% at day 7), while the HS5 expressing CD40L, IL4, and IL21 led to unprecedented proliferation rate (median 44%). The co-cultures mimicked the gene expression fingerprint of lymph node CLL cells (MYC, NFκB, and E2F signatures) and revealed novel vulnerabilities in CLL-T-cell-induced proliferation. Drug testing in co-cultures revealed for the first time that pan-RAF inhibitors fully block CLL proliferation. The co-culture model can be downscaled to five microliter volume for large drug screening purposes or upscaled to CLL PDXs by HS5-CD40L-IL4 ± IL21 co-transplantation. Co-transplanting NSG mice with purified CLL cells and HS5-CD40L-IL4 or HS5-CD40L-IL4-IL21 cells on collagen-based scaffold led to 47% or 82% engraftment efficacy, respectively, with ~20% of PDXs being clonally related to CLL, potentially overcoming the need to co-transplant autologous T-cells in PDXs.