Division of Hematology, Department of General Surgery and Medical-Surgical Specialties, A.O.U. “Policlinico-Vittorio Emanuele”, University of Catania, 95123 Catania, Italy
Lucia Longhitano
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Enrico La Spina
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Sebastiano Giallongo
Division of Hematology, Department of General Surgery and Medical-Surgical Specialties, A.O.U. “Policlinico-Vittorio Emanuele”, University of Catania, 95123 Catania, Italy
Laura Orlando
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Rosario Giuffrida
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Daniele Tibullo
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Paolo Fontana
Department of Medical Oncology, The Mediterranean Institute of Oncology, 95029 Viagrande, Italy
Ignazio Barbagallo
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Vincenzo Giuseppe Nicoletti
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Giovanni Li Volti
Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Vittorio Del Fabro
Division of Hematology, Department of General Surgery and Medical-Surgical Specialties, A.O.U. “Policlinico-Vittorio Emanuele”, University of Catania, 95123 Catania, Italy
Anna Rita Daniela Coda
Department of Medical and Surgical Sciences, University of Foggia, 71100 Foggia, Italy
Arcangelo Liso
Department of Medical and Surgical Sciences, University of Foggia, 71100 Foggia, Italy
Giuseppe Alberto Palumbo
Department of Scienze Mediche Chirurgiche e Tecnologie Avanzate “G.F. Ingrassia”, University of Catania, 95123 Catania, Italy
Chronic myeloid leukemia (CML), BCR-ABL1-positive, is classified as a myeloproliferative characterized by Philadelphia chromosome/translocation t(9;22) and proliferating granulocytes. Despite the clinical success of tyrosine kinase inhibitors (TKi) agents in the treatment of CML, most patients have minimal residual disease contained in the bone marrow microenvironment, within which stromal cells assume a pro-inflammatory phenotype that determines their transformation in cancer-associated fibroblasts (CAF) which, in turn can play a fundamental role in resistance to therapy. Insulin-like Growth Factor Binding Protein-6 (IGFBP-6) is expressed during tumor development, and is involved in immune-escape and inflammation as well, providing a potential additional target for CML therapy. Here, we aimed at investigating the role of IGFBP-6/SHH/TLR4 axis in TKi response. We used a CML cell line, LAMA84-s, and healthy bone marrow stromal cells, HS-5, in mono- or co-culture. The two cell lines were treated with Dasatinib and/or IGFBP-6, and the expression of inflammatory markers was tested by qRT-PCR; furthermore, expression of IGFBP-6, TLR4 and Gli1 were evaluated by Western blot analysis and immumocytochemistry. The results showed that both co-culture and Dasatinib exposure induce inflammation in stromal and cancer cells so that they modulate the expression of TLR4, and these effects were more marked following IGFBP-6 pre-treatment suggesting that this molecule may confer resistance through the inflammatory processes. This phenomenon was coupled with sonic hedgehog (SHH) signaling. Indeed, our data also demonstrate that HS-5 treatment with PMO (an inducer of SHH) induces significant modulation of TLR4 and overexpression of IGFPB-6 suggesting that the two pathways are interconnected with each other and with the TLR-4 pathway. Finally, we demonstrated that pretreatment with IGFBP-6 and/or PMO restored LAMA-84 cell viability after treatment with Dasatinib, suggesting that both IGFBP-6 and SHH are involved in the resistance mechanisms induced by the modulation of TLR-4, thus indicating that the two pathways may be considered as potential therapeutic targets.
