Cancer-associated fibroblasts promote bone invasion in oral squamous cell carcinoma

Abstract

Background:The molecular mechanisms involved in the invasion of bone by oral squamous cell carcinomas (OSCC) are poorly understood, and little is known about the role of cancer-associated fibroblasts (CAF), the presence of which confers a poor prognosis.Methods:Clinicopathological data from 277 OSCC cases involving bone resections were reviewed, and 32 cases thoroughly analysed histologically. Immunohistochemistry was used to examine αSMA, RANKL and OPG. Western blotting and qPCR were used to assess myofibroblast (CAF-like) differentiation, RANKL and OPG expression in vitro, and RANKL secretion was analysed by ELISA. Osteoclastogenesis was examined using TRAP staining, multinucleation and pit forming assays.Results:Fibrous stroma intervened between tumour and bone in the majority of cases, with no direct contact between cancer cells and bone. RANKL and OPG, two proteins key to regulating bone resorption, were expressed in tumour cells as well as fibrous stroma adjacent to bone and αSMA-positive myofibroblastic CAF were consistently seen infiltrating into bone ahead of tumour cells. Human primary osteoblasts cultured with conditioned media from human OSCC-derived cells and human primary CAF showed a significant increase in RANKL and a decline in OPG mRNA expression. RANKL secretion was significantly increased in primary oral fibroblasts induced to differentiate into a CAF-like phenotype by transforming growth factor-β1 (TGF-β1) treatment and in primary CAF. Indirect co-culture of murine macrophages with conditioned media from CAF (experimentally derived and isolated from OSCCs) resulted in a marked increase in osteoclastogenesis (in excess of that provoked by cancer cells) determined by tartrate-resistant acid phosphatase activity, multinucleation and resorption pit formation.Conclusions:This study is the first to describe a functional role for CAFs in bone invasion and turnover, identifying a novel potential therapeutic target and diagnostic indicator in this difficult to treat bone invasive malignancy.

The extra domain A of fibronectin facilitates osteoclastogenesis in radicular cysts through vascular endothelial growth factor

“…Fibronectin (FN) is the main component of the ECM, and in most normal adult tissues, isoforms containing domains EDA (EDA + FN), EDB (EDB + FN) and IIICS (CS1‐FN) are absent (Liu et al , Lv et al ). However, myofibroblasts generate these isoforms via alternative splicing of the FN gene, especially during inflammation, wound healing or tumour formation (Kalluri & Zeisberg ), suggesting their involvement in bone destruction (Elmusrati et al ). In odontogenic tumours or cysts, the stroma contains these activated fibroblasts as well (Kouhsoltani et al ), from which EDA + FN can be generated.…”

Interaction between IGF2‐PI3K axis and cancer‐associated‐fibroblasts promotes anal squamous carcinogenesis

“…Similarly, stromal cells, including cancerassociated fibroblasts (CAF), have not yet been studied in ASCC, although CAFs have been reported to play a role in cancer progression in other types of squamous cell carcinoma. 9,10 In this study, we provide the first molecular gene expression profile of targets linked to a panel of targeted therapies in ASCC and demonstrate a central role for the targetable IGF2-PI3K axis, involving tumour cell crosstalk with CAFs.…”

“…Nevertheless, all of these analyses have identified PI3K/AKT/mTOR as the pathway most commonly altered in ASCC. Similarly, stromal cells, including cancer‐associated fibroblasts (CAF), have not yet been studied in ASCC, although CAFs have been reported to play a role in cancer progression in other types of squamous cell carcinoma …”

Cancer stem cells and fibroblast niche cross talk in an in‐vitro oral dysplasia model

“…[20][21][22] CAF and/or endothelial cells have also been reported to induce CSC profile and reduce apoptosis in oral and other cancer cells. 23,24 Studies have also reported an increase in resistance to gemcitabine, 25 cisplatin 26 in parallel with increased MDR gene expressions in lung, breast, and oral squamous cell carcinomas under the influence of CAFs. 26,27 These evidences notwithstanding, CSC behavior and the niche effect in early oral dysplastic lesions have not been delineated.…”

“…Co‐culture of stromal cells such as omental adipose derived and/or bone‐marrow mesenchymal stem cells with tumor associated macrophages have been correlated with aberrant expression of stem cell profile in ovarian, myeloma, breast, and gastric cancer cells . CAF and/or endothelial cells have also been reported to induce CSC profile and reduce apoptosis in oral and other cancer cells . Studies have also reported an increase in resistance to gemcitabine, cisplatin in parallel with increased MDR gene expressions in lung, breast, and oral squamous cell carcinomas under the influence of CAFs .…”