Apoptosis induction by combination of drugs or a conjugated molecule associating non-steroidal anti-inflammatory and nitric oxide donor effects in medullary thyroid cancer models: implication of the tumor suppressor p73.
BACKGROUND
Medullary thyroid cancer (MTC) is a C-cell neoplasm. Surgery remains its main treatment. Promising therapies based on tyrosine kinase inhibitors demand careful patient selection. We previously observed that two non-steroidal anti-inflammatory drugs (NSAID), indomethacin, celecoxib, and nitric oxide (NO) prevented tumor growth in a model of human MTC cell line (TT) in nude mice.


METHODS
In the present study, we tested the NO donor: glyceryl trinitrate (GTN), at pharmacological dose, alone and in combination with each of the two NSAIDs on TT cells. We also assessed the anti-proliferative potential of NO-indomethacin, an indomethacin molecule chemically conjugated with a NO moiety (NCX 530, Nicox SA) on TT cells and indomethacin/GTN association in rMTC 6-23 cells. The anti-tumoral action of the combined sc. injections of GTN with oral delivery of indomethacin was also studied on subcutaneous TT tumors in nude mice. Apoptosis mechanisms were assessed by expression of caspase-3, TAp73α, TAp73α inhibition by siRNA or Annexin V externalisation.


RESULTS
The two NSAIDs and GTN reduced mitotic activity in TT cells versus control (cell number and PCNA protein expression). The combined treatments amplified the anti-tumor effect of single agents in the two tested cell lines and promoted cell death. Moreover, indomethacin/GTN association stopped the growth of established TT tumors in nude mice. We observed a significant cleavage of full length PARP, a caspase-3 substrate. The cell death appearance was correlated with a two-fold increase in TAp73α expression, with inhibition of apoptosis after TAp73α siRNA addition, demonstrating its crucial role in apoptosis.


CONCLUSIONS
Association of NO with NSAID exhibited amplified anti-tumoral effects on in vitro and in vivo MTC models by inducing p73-dependent apoptotic cell death.
UMR 8203, Gustave Roussy, Laboratoire de Vectorologie et de Thérapeutiques Anticancéreuses, Villejuif, 94805 France ; UMR 8203, CNRS, Laboratoire de Vectorologie et Thérapeutiques Anticancéreuses, Villejuif, 94805 France ; UMR 8203, Univ Paris-Sud, Laboratoire de Vectorologie et Thérapeutiques Anticancéreuses, Villejuif, 94805 France.
Thierry
T
Ragot
Sorbonne Universités, UPMC University Paris 06, plateforme LIMP, Laboratoire d'Imagerie Médicale Positonique, Hôpital Tenon, Paris, 75020 France.
Claire
C
Provost
Sorbonne Universités, UPMC University Paris 06, plateforme LIMP, Laboratoire d'Imagerie Médicale Positonique, Hôpital Tenon, Paris, 75020 France.
Aurélie
A
Prignon
Hopital Delafontaine, Endocrinology Unit, Saint Denis, France.
Régis
R
Cohen
IBBMC, CNRS 8619, bat 430, Université Paris Sud XI, Orsay, Paris, 91405 France.
Michel
M
Lepoivre
Sorbonne Universités, UPMC University Paris 06, plateforme LIMP, Laboratoire d'Imagerie Médicale Positonique, Hôpital Tenon, Paris, 75020 France.
Sylvie
S
Lausson
Apoptosis; Medullary thyroid carcinoma; NO-donors; Non-steroidal anti-inflammatory drugs; TT cells; rMTC 6–23 cells