The cytotoxic activity of the phage E protein suppress the growth of murine B16 melanomas in vitro and in vivo.
Novel treatment modalities, including gene therapy, are needed for patients with advanced melanoma. The E gene from the phage varphiX174 encodes a 91-aa protein which lyses Escherichia coli by formation of a transmembrane tunnel structure. To evaluate whether this E gene has a cytotoxic impact on melanoma cells in vitro and in vivo, and could therefore be used as a new therapeutic strategy for this tumor type, we selected the B16-F10 murine melanoma cell line as a model. We used a nonviral gene delivery approach (pcDNA3.1/E plasmid) to study the inhibition of melanoma cells' proliferation in vitro and direct intratumoral injection of pcDNA3.1/E complexed with jetPEI to deliver E cDNA to rapidly growing murine melanomas, and found that the E gene has both a strong antiproliferative effect in B16-F10 cells in vitro and induces an efficient decrease in melanoma tumor volume in vivo (90% in 15 days). Interestingly, the GFP-E fusion protein expressed in melanoma cells was located in the mitochondria. In vitro and in vivo analysis demonstrated significant functional and morphological mitochondrial alterations accompanied by a significant increase of cytochrome c and active caspase-3 and -9 in transfected cells, which suggests that tumoral cell death is mediated by the mitochondrial apoptotic pathway. These results show that E gene expression in melanoma cells has an extraordinary antitumor effect, which means it may be a new candidate for an effective strategy for melanoma treatment.
Ortiz
Raúl
R
Instituto de Biopatología y Medicina Regenerativa (IBIMER), Depto. de Anatomía y Embriología, Facultad de Medicina, Universidad de Granada, 18071, Granada, Spain.
Prados
Jose
J
Melguizo
Consolacion
C
Rama
Ana R
AR
Segura
Ana
A
Rodríguez-Serrano
Fernando
F
Boulaiz
Houria
H
Hita
Fidel
F
Martinez-Amat
Antonio
A
Madeddu
Roberto
R
Ramos
Juan L
JL
Aranega
Antonia
A
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004279:DNA, Viral / Q000008:administration & dosage; D008546:Melanoma, Experimental; D051379:Mice; D008928:Mitochondria / Q000187:drug effects; D024101:Mitochondrial Proteins / Q000187:drug effects; D012097:Repressor Proteins / Q000494:pharmacology* / Q000627:therapeutic use; D054334:Viral Regulatory and Accessory Proteins / Q000494:pharmacology* / Q000627:therapeutic use
D000970:Antineoplastic Agents; D004279:DNA, Viral; D024101:Mitochondrial Proteins; D012097:Repressor Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins