Acta Neuropathol (2007) 114:135–145 DOI 10.1007/s00401-007-0212-y 123 ORIGINAL PAPER Human parathyroid hormone-related protein and human parathyroid hormone receptor type 1 are expressed in human medulloblastomas and regulate cell proliferation and apoptosis in medulloblastoma-derived cell lines Marco Gessi · Giovanni Monego · Gabriella Calviello · Paola Lanza · Felice Giangaspero · Andrea Silvestrini · Libero Lauriola · Franco O. Ranelletti Received: 12 December 2006 / Revised: 21 February 2007 / Accepted: 22 February 2007 / Published online: 20 March 2007  Springer-Verlag 2007 Abstract Human parathyroid hormone-related protein (hPTHrP), identiWed in patients with paraneoplastic hyper- calcemia and expressed by diVerent cell types during devel- opment and adult life, plays important roles in many human neoplasms. Immunohistochemical and RT-PCR analyses of hPTHrP and human parathyroid hormone receptor type 1 (PTHR-1) in primary medulloblastoma conWrmed their expression in both classic and desmoplastic variants at RNA and protein levels. To evaluate the functional role of hPTHrP, DAOY and D283 medulloblastoma and U87MG glioma cells, expressing high levels of hPTHrP and PTHR- 1, were treated with anti-sense oligonucleotides for hPTHrP. Anti-sense treatment produced in all cell lines a decrease of cell proliferation and clonogenic activity and an increase of apoptosis, while addition of exogenous hPTHrP (1–37) pre- vented these eVects. Anti-sense induced the increase of Caspase-3, Fas (CD95) mRNAs and Bax/Bcl-2 mRNA ratio after 12 h of cell treatment. Exogenous hPTHrP (1–37) increased intracellular Ca 2+ concentration in DAOY cells as revealed by FURA. Anti-sense treated cells showed a sig- niWcant decrease of steady-state levels of intracellular Ca 2+ , which was reverted by addition of exogenous hPTHrP (1–37). This study indicates that hPTHrP and PTHR-1 are expressed in medulloblastoma and could promote tumor growth, protecting cells from apoptosis. Keywords hPTHrP · PTHR-1 · Medulloblastoma · Cell proliferation · Apoptosis Introduction Human parathyroid hormone-related protein (hPTHrP), identiWed in patients with paraneoplastic hypercalcemia, is expressed by various tissues during development and adult life [29, 38, 39]. PTHrP is secreted in a regulated or constit- utive fashion, depending on the cell type [19, 35], function- ing in a classical endocrine, paracrine, and autocrine pathways or via intracrine way, through a functional nuclear localization segment (NLS) that can target the pro- tein to the nucleus [16]. M. Gessi and G. Monego contributed equally to this work. M. Gessi · P. Lanza · L. Lauriola Department of Pathology, Catholic University, Rome, Italy M. Gessi Division of Neuropathology, National Neurological Institute “C.Besta”, Milan, Italy G. Monego Institute of Human Anatomy and Cellular Biology, Catholic University, Rome, Italy G. Calviello Institute of General Pathology, Catholic University, Rome, Italy F. Giangaspero Department of Experimental Medicine and Pathology, University of Rome “La Sapienza”, Rome, Italy A. Silvestrini Institute of Biochemistry, Catholic University, Rome, Italy F. O. Ranelletti (&) Institute of Histology, Catholic University, Largo F.Vito 1, 00168 Rome, Italy e-mail: ranelletti@rm.unicatt.it F. Giangaspero IRCCS Pozzilli, (IS), Italy