Anti-proliferative and anti-tumour effects of lymphocyte-derived microparticles are neither species- nor tumour-type specific.
BACKGROUND
Unregulated cell proliferation or growth is a prominent characteristic of cancer. We have previously demonstrated that LMPs (cell membrane microparticles derived from apoptotic human CEM T lymphoma cells stimulated with actinomycin D) strongly suppress the proliferation of not only human endothelial cells but also mouse Lewis lung carcinoma cells.


METHODS
LMPs were generated either from CEM T cells using different stimuli or from 3 different types of lymphocytes. The effects of LMPs on cancer cell proliferation were examined using cell lines from different species and tissues. The cell cycle kinetics was evaluated by FACS and the expression of cell cycle-related genes was determined using quantitative RT-PCR. The in vivo anti-tumor effect of LMPs was investigated using xenografts and allografts.


RESULTS
LMPs at doses far above physiological levels dramatically suppressed the proliferation of cancer cells in a non species-specific manner. LMPs selectively target high proliferating cells and their anti-proliferative effect is not dependent on parental cell origin or stimuli. The anti-proliferative effect of LMPs was due to induction of cell-cycle arrest in G0/G1, with associated increases in expression of the cyclin-dependent kinase inhibitors p15(INK4b), p16(INK4a), and p21(Cip1). In vivo, LMPs significantly suppressed tumor growth in animal tumor models.


CONCLUSIONS
These results highlight the potential role of LMPs in modulating the growth of high proliferating cells. Given that cell-based therapies are considered less toxic than pharmacologic approaches and have the potential to target multiple pathways in a synergistic manner, LMPs may serve as a veritable option for cancer treatment.
Departments of Pediatrics and Pharmacology, University of Montréal, Montréal, QC, Canada.
Chun
C
Yang
Department of Pulmonology, Chongqing Southwest Hospital, Third Military Medical University, Chongqing, China.
Wei
W
Xiong
Department of Pulmonology, Chongqing Southwest Hospital, Third Military Medical University, Chongqing, China.
Qian
Q
Qiu
Departments of Pediatrics and Pharmacology, University of Montréal, Montréal, QC, Canada.
Houda
H
Tahiri
Department of Ophthalmology, University of Montréal, Montréal, QC, Canada.
Rosanne
R
Superstein
Departments of Pediatrics and Pharmacology, University of Montréal, Montréal, QC, Canada.
Anne-Sophie
AS
Carret
Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montréal, Montréal, QC, Canada.
Przemyslaw
P
Sapieha
Departments of Pediatrics and Pharmacology, University of Montréal, Montréal, QC, Canada.
Pierre
P
Hardy
anti-proliferation; cell cycle; lymphocytes; microparticles; tumour growth