Abstract:
Background:
Although basement membrane was traditionally considered an inert barrier
that tumour cells had to cross before invasion into the surrounding stroma, recent studies
suggest that basement membrane components are not only degraded during tumour
progression, but also newly synthesised at the invasive front.
Objective:
This study aimed at evaluating (1) the expression of basement membrane proteins
in human oral carcinogenesis and (2) the role that epithelial–mesenchymal interactions play
on it, by using an
in vitro
oral cancer progression model.
Material and methods:
In vitro
three-dimensional (3D) organotypic cultures of normal, early
neoplastic and neoplastic human oral mucosa were developed by growing primary normal
human oral keratinocytes, dysplastic human oral keratinocytes (DOK cell line), and neo-
plastic human oral keratinocytes (PE/CA-PJ15 cell line) on type I collagen biomatrices, with
or without primary fibroblasts isolated from normal human oral mucosa. The cultured
tissues were immunohistochemically assessed for the expression of the major basement
membrane proteins laminin-332, type IV collagen, and fibronectin.
Results:
Expression of laminin-332, type IV collagen, and fibronectin was gradually more
pronounced in neoplastic models when compared to normal mucosa models, and, with the
exception of laminin-332, it was further enhanced by presence of fibroblasts. Deposition of
type IV collagen at the epithelium–biomatrix interface occurred only in presence of fibro-
blasts, as well as the extracellular matrix deposition of fibronectin.
Conclusions:
These findings, obtained in a 3D
in vitro
model that closely mirrors the
in vivo
human oral cancer progression, show an enhanced basement membrane protein expres-
sion during human oral cancer progression that is dependent on the epithelial–mesench-
ymal environment, respectively the existence of fibroblasts.
