Martina Cordella1, Claudio Tabolacci2, Cinzia Senatore1, Stefania Rossi1, Sabina Mueller3, Carla Lintas4, Adriana Eramo1, Daniela D'Arcangelo5, Salvatore Valitutti6, Antonio Facchiano5, Francesco Facchiano1. 1. Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy. 2. Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy. Electronic address: claudiotabolacci@tiscali.it. 3. Cancer Research Center of Toulouse, Toulouse, France. 4. Center for Neurodevelopmental Disorders, Laboratory of Molecular Psychiatry and Neurogenetics, Department of Medicine, University Campus Bio-Medico, Rome, Italy. 5. Istituto Dermopatico dell'Immacolata, IDI-IRCSS, Rome, Italy. 6. Cancer Research Center of Toulouse, Toulouse, France; Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse, Toulouse, France.
Abstract
AIMS: Cutaneous melanoma is the most aggressive skin cancer, derived from neoplastic transformation of melanocytes. Since several evidences highlighted the importance of a hierarchical model of differentiation among cancer cells, closely related to resistance mechanisms and tumor relapse, we investigated the effects of theophylline (Theo), a methylxanthine commonly used in treatment of respiratory diseases, on melanoma cells with different degree of differentiation, including patient-derived melanoma-initiating cells. MATERIALS AND METHODS: The antiproliferative and antimetastatic effects of Theo was demonstrated by cell counting, adhesion and migration assays on A375 and SK-MEL-30 cells. Further, Theo ability to reduce cell growth was highly significant in A375-derived spheroids and in two patient-derived melanoma-initiating cells (MICs). In order to identify pathways potentially involved in the antineoplastic properties of Theo, a comparative mass spectrometry proteomic analysis was used. Then, melanin content, tyrosinase and tissue transglutaminase activities as differentiation markers and actin re-organization through confocal microscopy were evaluated. Furthermore, a secretome profile of MICs after Theo treatments was performed by multiplex immunoassay. KEY FINDINGS: Obtained results demonstrate inhibitory effects of Theo on melanoma cell proliferation and migration, mainly in MICs, together with the induction of differentiation parameters. Moreover, our data indicate that the known anti-melanoma effect of Theo is due also to its ability to interfere with cytoskeleton dynamics and to induce the secretion of inflammatory molecules involved in recruitment of immunosuppressive cells in tumor microenvironment. SIGNIFICANCE: Data strongly suggest that Theo supplement, either as drug or as dietary supply, may represent a potent additional weapon against melanoma.
AIMS: Cutaneous melanoma is the most aggressive skin cancer, derived from neoplastic transformation of melanocytes. Since several evidences highlighted the importance of a hierarchical model of differentiation among cancer cells, closely related to resistance mechanisms and tumor relapse, we investigated the effects of theophylline (Theo), a methylxanthine commonly used in treatment of respiratory diseases, on melanoma cells with different degree of differentiation, including patient-derived melanoma-initiating cells. MATERIALS AND METHODS: The antiproliferative and antimetastatic effects of Theo was demonstrated by cell counting, adhesion and migration assays on A375 and SK-MEL-30 cells. Further, Theo ability to reduce cell growth was highly significant in A375-derived spheroids and in two patient-derived melanoma-initiating cells (MICs). In order to identify pathways potentially involved in the antineoplastic properties of Theo, a comparative mass spectrometry proteomic analysis was used. Then, melanin content, tyrosinase and tissue transglutaminase activities as differentiation markers and actin re-organization through confocal microscopy were evaluated. Furthermore, a secretome profile of MICs after Theo treatments was performed by multiplex immunoassay. KEY FINDINGS: Obtained results demonstrate inhibitory effects of Theo on melanoma cell proliferation and migration, mainly in MICs, together with the induction of differentiation parameters. Moreover, our data indicate that the known anti-melanoma effect of Theo is due also to its ability to interfere with cytoskeleton dynamics and to induce the secretion of inflammatory molecules involved in recruitment of immunosuppressive cells in tumor microenvironment. SIGNIFICANCE: Data strongly suggest that Theo supplement, either as drug or as dietary supply, may represent a potent additional weapon against melanoma.