Significance of cancer stroma for bone destruction in oral squamous cell carcinoma using different cancer stroma subtypes

Abstract

Stromal cells in the tumor microenvironment (TME) can regulate the progression of numerous types of cancer; however, the bone invasion of oral squamous cell carcinoma (OSCC) has been poorly investigated. In the present study, the effect of verrucous SCC-associated stromal cells (VSCC-SCs), SCC-associated stromal cells (SCC-SCs) and human dermal fibroblasts on bone resorption and the activation of HSC-3 osteoclasts in vivo were examined by hematoxylin and eosin, AE1/3 (pan-cytokeratin) and tartrate-resistant acid phosphatase staining. In addition, the expression levels of matrix metalloproteinase (MMP)9, membrane-type 1 MMP (MT1-MMP), Snail, receptor activator of NF-κB ligand (RANKL) and parathyroid hormone-related peptide (PTHrP) in the bone invasion regions of HSC-3 cells were examined by immunohistochemistry. The results suggested that both SCC-SCs and VSCC-SCs promoted bone resorption, the activation of osteoclasts, and the expression levels of MMP9, MT1-MMP, Snail, RANKL and PTHrP. However, SCC-SCs had a more prominent effect compared with VSCC-SCs. Finally, microarray data were used to predict potential genes underlying the differential effects of VSCC-SCs and SCC-SCs on bone invasion in OSCC. The results revealed that IL1B, ICAM1, FOS, CXCL12, INS and NGF may underlie these differential effects. In conclusion, both VSCC-SCs and SCC-SCs may promote bone invasion in OSCC by enhancing the expression levels of RANKL in cancer and stromal cells mediated by PTHrP; however, SCC-SCs had a more prominent effect. These findings may represent a potential regulatory mechanism underlying the bone invasion of OSCC.

Investigation of bone invasion and underlying mechanisms of oral cancer using a cell line‑derived xenograft model

“…However, the effects of different properties of the normal stroma on bone resorption have not yet been fully elucidated. Our previous studies assessed the effect of different subtypes of cancer stroma on bone invasion of both HSC-2 and HSC-3 cells (20)(21)(22). Furthermore, our previous study also assayed the effects of normal stroma G-SCs and P-SCs on bone invasion of OSCC but did not provide a detailed description of the bone invasion type and potential regulatory mechanism (5).…”

“…However, previous studies on the tumor stroma have only reported that the cancer parenchyma subordinately dominates the stroma and contributes to the progression of cancerous tissue (18,19); therefore, the mechanisms underlying the effect of the cancer stroma on the parenchyma are not clear. Our previous studies reported that the cancer stroma regulates bone invasion of human OSCC cell lines, HSC-2 and HSC-3 cells (20)(21)(22)(23). Therefore, not only gingival cancer but also tongue cancer induces bone invasion.…”

“…In the present study, the role of G-SCs and P-SCs in bone invasion in OSCC and their potential regulatory mechanisms were assessed. The differences in bone resorption capacity between gingival connective tissue and the PDL with respect to osteoclasts, MMPs and epithelial-mesenchymal transition (EMT) and RANKL and PTHrP, which have been reported as associated with bone resorption ( 22 ), were evaluated. The human OSCC HSC-3 cell line was selected for use as a cancer cell model as it is a moderately to poorly differentiated oral cancer cell line with bone invasion ability and is widely used in bone invasion studies ( 17 , 22 ).…”

“…The differences in bone resorption capacity between gingival connective tissue and the PDL with respect to osteoclasts, MMPs and epithelial-mesenchymal transition (EMT) and RANKL and PTHrP, which have been reported as associated with bone resorption ( 22 ), were evaluated. The human OSCC HSC-3 cell line was selected for use as a cancer cell model as it is a moderately to poorly differentiated oral cancer cell line with bone invasion ability and is widely used in bone invasion studies ( 17 , 22 ). Similarly, the murine leukemia RAW264.7 cell line was selected for use as an osteoclast cell model based on its reported applications in bone invasion research ( 22 , 24 ).…”

“…The human OSCC HSC-3 cell line was selected for use as a cancer cell model as it is a moderately to poorly differentiated oral cancer cell line with bone invasion ability and is widely used in bone invasion studies ( 17 , 22 ). Similarly, the murine leukemia RAW264.7 cell line was selected for use as an osteoclast cell model based on its reported applications in bone invasion research ( 22 , 24 ). Human dermal fibroblasts (HDFs) were selected for use as a negative control for G-SCs and P-SCs as they are normal fibroblasts that remain unaffected by the cancer cells ( 23 ).…”