title: Pre-clinical evaluation of voltage-gated calcium channel blockers derived from the spider P. nigriventer in glioma progression.
abstract: This study investigated the effects of P/Q- and N-type voltage-gated calcium channel (VGCC) blockers derived from P. nigriventer in glioma progression, by means of in vitro and in vivo experiments. Glioma cells M059J, U-138MG and U-251MG were used to evaluate the antiproliferative effects of P/Q- and N-type VGCC inhibitors PhTx3-3 and Phα1β from P. nigriventer (0.3-100 pM), in comparison to MVIIC and MVIIA from C. magus (0.3-100 pM), respectively. The toxins were also analyzed in a glioma model induced by implantation of GL261 mouse cells. PhTx3-3, Phα1β and MVIIA displayed significant inhibitory effects on the proliferation and viability of all tested glioma cell lines, and evoked cell death mainly with apoptosis characteristics, as indicated by Annexin V/propidium iodide (PI) positivity. The antiproliferative effects of toxins were confirmed by flow cytometry using Ki67 staining. None of the tested toxins altered the proliferation rates of the N9 non-tumor glial cell line. Noteworthy, the administration of the preferential N-type VGCC inhibitors, Phα1β (50 pmol/site; i.c.v.), its recombinant form CTK 01512-2 (50 pmol/site; i.c.v. and i.t.), or MVIIA (10 pmol/site; i.c.v.) caused significant reductions of tumor areas in vivo. N-type VGCC inhibition by Phα1β, CTK 01512-2, and MVIIA led to a marked increase of GFAP-activated astrocytes, and Iba-1-positive microglia, in the peritumoral region, which might explain, at least in part, the inhibitory effects of the toxins in tumor development. This study provides novel evidence on the potential effects of P. nigriventer-derived P/Q-, and mainly, N-type VGCC inhibitors, in glioma progression.
authors.affiliation: PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Porto Alegre, RS, Brazil; PUCRS, Instituto de Toxicologia e Farmacologia, Porto Alegre, RS, Brazil.
authors.forename: Natália Fontana
authors.initials: NF
authors.lastname: Nicoletti
authors.affiliation: PUCRS, Faculdade de Farmácia, Porto Alegre, RS, Brazil.
authors.forename: Thaís Cristina
authors.initials: TC
authors.lastname: Erig
authors.affiliation: PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Porto Alegre, RS, Brazil.
authors.forename: Rafael Fernandes
authors.initials: RF
authors.lastname: Zanin
authors.affiliation: Serviço de Neurocirurgia, Hospital São José, Irmandade da Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, RS, Brazil; UCS, Faculdade de Medicina, Departamento de Neurocirurgia, Caxias do Sul, RS, Brazil.
authors.forename: Marcelo Ricardo
authors.initials: MR
authors.lastname: Roxo
authors.affiliation: Serviço de Neurocirurgia, Hospital São José, Irmandade da Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Nelson Pires
authors.initials: NP
authors.lastname: Ferreira
authors.affiliation: UFMG, Faculdade de Medicina, Laboratório de Neurociências, Belo Horizonte, MG, Brazil.
authors.forename: Marcus Vinicius
authors.initials: MV
authors.lastname: Gomez
authors.affiliation: PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Porto Alegre, RS, Brazil; PUCRS, Instituto de Toxicologia e Farmacologia, Porto Alegre, RS, Brazil; PUCRS, Faculdade de Farmácia, Porto Alegre, RS, Brazil.
authors.forename: Fernanda Bueno
authors.initials: FB
authors.lastname: Morrone
authors.affiliation: PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Porto Alegre, RS, Brazil; PUCRS, Instituto de Toxicologia e Farmacologia, Porto Alegre, RS, Brazil; PUCRS, Faculdade de Odontologia, Laboratório de Patologia, Porto Alegre, RS, Brazil. Electronic address: camposmmartha@yahoo.com.
authors.forename: Maria Martha
authors.initials: MM
authors.lastname: Campos
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020864:Calcium Channels, N-Type / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005910:Glioma / Q000188:drug therapy; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009479:Neuropeptides / Q000494:pharmacology*; D013111:Spider Venoms / Q000494:pharmacology*; D013112:Spiders / Q000737:chemistry*
chemical_list: D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D009479:Neuropeptides; D013111:Spider Venoms; C064022:Tx1 neurotoxin; C098736:Tx3 neurotoxin
keywords: Glioblastoma; High-voltage-gated calcium channels; Phoneutria nigriventer