Inhibition of oral mucosal cell wound healing by bisphosphonates.
OBJECTIVE
Bisphosphonates (BPs) are a widely used class of drugs that are effective in the treatment and prevention of osteoporosis, hypercalcemia of malignancy, and bone metastases associated with multiple myeloma, breast cancer, and other solid tumors. In the past several years there have been numerous reports describing the occurrence of osteonecrosis of the jaws (ONJ) associated with these drugs. Whether the ONJ lesion initiates in the oral mucosa or derives from the underlying bone is not well understood. In this report we describe the effect of pamidronate, a second-generation BP, on oral mucosal cells.


METHODS
Murine oral keratinocytes were isolated and exposed to pamidronate at a range of clinically relevant doses. Cellular proliferation was measured using a MTS/PMS reagent-based kit and wound healing was examined with a scratch assay. To determine whether oral keratinocytes undergo apoptosis following exposure to pamidronate, TUNEL, caspase-3, and DAPI apoptosis assays were performed.


RESULTS
We show that BP pretreatment of oral mucosal cells inhibits proliferation and wound healing at clinically relevant doses, and that this inhibition is not due to cellular apoptosis.


CONCLUSIONS
To our knowledge this is the first report investigating the effect of nitrogen-containing BPs on oral mucosal cells. This study suggests that BPs inhibit oral keratinocyte wound healing which may play a significant role in the initiation of ONJ.
Landesberg
Regina
R
Columbia University, College of Dental Medicine, Division of Oral and Maxillofacial Surgery, New York, NY 10032, USA. rl351@columbia.edu
Cozin
Matthew
M
Cremers
Serge
S
Woo
Victoria
V
Kousteni
Stavroula
S
Sinha
Satrajit
S
Garrett-Sinha
LeeAnn
L
Raghavan
Srikala
S
D000818:Animals; D017209:Apoptosis; D050071:Bone Density Conservation Agents / Q000737:chemistry / Q000633:toxicity*; D053148:Caspase 3 / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004164:Diphosphonates / Q000737:chemistry / Q000633:toxicity*; D005456:Fluorescent Dyes / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D007211:Indoles / Q000378:metabolism; D007571:Jaw Diseases / Q000139:chemically induced; D015603:Keratinocytes / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D009061:Mouth Mucosa / Q000187:drug effects* / Q000201:enzymology; D009584:Nitrogen; D010020:Osteonecrosis / Q000139:chemically induced; D000077268:Pamidronate; D014945:Wound Healing / Q000187:drug effects*
D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D005456:Fluorescent Dyes; D007211:Indoles; C007293:DAPI; D053148:Caspase 3; D009584:Nitrogen; D000077268:Pamidronate