American Association for Cancer Research
10780432ccr143379-sup-141372_2_supp_3156097_nv3f6c.doc (107.5 kB)

Supplementary Table S2 from Mithramycin Depletes Specificity Protein 1 and Activates p53 to Mediate Senescence and Apoptosis of Malignant Pleural Mesothelioma Cells

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journal contribution
posted on 2023-03-31, 18:22 authored by Mahadev Rao, Scott M. Atay, Vivek Shukla, Young Hong, Trevor Upham, R. Taylor Ripley, Julie A. Hong, Mary Zhang, Emily Reardon, Patricia Fetsch, Markku Miettinen, Xinmin Li, Cody J. Peer, Tristan Sissung, William D. Figg, Assunta De Rienzo, Raphael Bueno, David S. Schrump

Genes Modulated by MM (25 or 100nM) and SP1knockdown/p53 over-expression in MES1 and/or MES7 Cells.





Purpose: Specificity protein 1 (SP1) is an oncogenic transcription factor overexpressed in various human malignancies. This study sought to examine SP1 expression in malignant pleural mesotheliomas (MPM) and ascertain the potential efficacy of targeting SP1 in these neoplasms.Experimental Design: qRT-PCR, immunoblotting, and immunohistochemical techniques were used to evaluate SP1 expression in cultured MPM cells and MPM specimens and normal mesothelial cells/pleura. MTS, chemotaxis, soft agar, β-galactosidase, and Apo-BrdUrd techniques were used to assess proliferation, migration, clonogenicity, senescence, and apoptosis in MPM cells following SP1 knockdown, p53 overexpression, or mithramycin treatment. Murine subcutaneous and intraperitoneal xenograft models were used to examine effects of mithramycin on MPM growth in vivo. Microarray, qRT-PCR, immunoblotting, and chromatin immunoprecipitation techniques were used to examine gene expression profiles mediated by mithramycin and combined SP1 knockdown/p53 overexpression and correlate these changes with SP1 and p53 levels within target gene promoters.Results: MPM cells and tumors exhibited higher SP1 mRNA and protein levels relative to control cells/tissues. SP1 knockdown significantly inhibited proliferation, migration, and clonogenicity of MPM cells. Mithramycin depleted SP1 and activated p53, dramatically inhibiting proliferation and clonogenicity of MPM cells. Intraperitoneal mithramycin significantly inhibited growth of subcutaneous MPM xenografts and completely eradicated mesothelioma carcinomatosis in 75% of mice. Mithramycin modulated genes mediating oncogene signaling, cell-cycle regulation, senescence, and apoptosis in vitro and in vivo. The growth-inhibitory effects of mithramycin in MPM cells were recapitulated by combined SP1 knockdown/p53 overexpression.Conclusions: These findings provide preclinical rationale for phase II evaluation of mithramycin in patients with mesothelioma. Clin Cancer Res; 22(5); 1197–210. ©2015 AACR.