title: A Preliminary Study of the Action of Virtosomes from Non-dividing Cells on Tumour Cell Replication in vitro and in vivo.
abstract: BACKGROUND
  A DNA-RNA-lipoprotein complex, termed as virtosome, is released spontaneously from healthy human, other mammalian, avian, amphibian and plant cells in a regulated and energy-dependent manner. Studies on human and mouse lymphocytes, hepatocytes, NIH 3T3 cells and mouse tumour cell lines have shown that virtosomes may be acting as inter-cellular messengers. In particular, virtosomes from non-dividing cells blocked 3H-thymidine incorporation into DNA in tumour cell lines.
  
  
  OBJECTIVE
  Study of the effect of virtosomes on tumors "in vivo" and "in vitro".
  
  
  RESULTS
  The present study shows in vitro effects of virtosomes isolated from rat liver, essentially nondividing cell populations, on cultures of healthy smooth muscle cells (SMC), human umbilical vein endothelial cells (HUVEC), human fibroblasts (h-fibroblasts) and mouse embryonic fibroblasts (NIH-3T3) together with two tumour cell lines, human Duke's type B colorectal adenocarcinoma cells (SW480) and human connective tissue fibrosarcoma cells (HT1080). Multiplication of all cell lines was inhibited by the liver virtosomal preparation even with various dilutions of the extract (100 - 0.5%). In an in vivo study, tumours were initiated by subcutaneous injection of 1.0 x 106 DHD/K12-PROb cells in 6 weeks old male BIDX rats. Visible tumours (<1cm) appeared after 3 weeks and lung metastases after 8 weeks (80%). Virtosomes introduced via a tail vein on tumour initiation resulted in a reduction in tumour size and number.
  
  
  CONCLUSIONS
  Virtosomal preparation from a non-dividing cell population inhibited cell division, reduced tumour size and partially blocked metastasis.
authors.affiliation: New Therapy Laboratory, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz, Avda Reyes Catolicos 2, 28040 Madrid. Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Garcia-Arranz
authors.affiliation: Surgery Department, Medicine School, Universidad Autonoma de Madrid. C/ Arzobispo Morcillo s/n 28029, Madrid. Spain.
authors.forename: Damian
authors.initials: D
authors.lastname: Garcia-Olmo
authors.affiliation: New Therapy Laboratory, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz, Avda Reyes Catolicos 2, 28040 Madrid. Spain.
authors.forename: Luz
authors.initials: L
authors.lastname: Vega-Clemente
authors.affiliation: 6, Pedro Meylan, 1208 Geneva. Switzerland.
authors.forename: Maurice
authors.initials: M
authors.lastname: Stroun
mesh_terms: D000818:Animals; D002455:Cell Division; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D006801:Humans; D008074:Lipoproteins / Q000378:metabolism*; D008297:Male; D051379:Mice; D041681:NIH 3T3 Cells; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology*; D012313:RNA / Q000378:metabolism*; D051381:Rats
chemical_list: D008074:Lipoproteins; D012313:RNA; D004247:DNA
keywords: Non-dividing cell virtosomes; metastasis; mitotic count; tumour cell replication; tumours