The Origin of Stroma Influences the Biological Characteristics of Oral Squamous Cell Carcinoma

Simple Summary Normal stromal cells play a significant role in the progression of cancers but are poorly investigated in oral squamous cell carcinoma (OSCC). In this study, we found that stromal cells derived from the gingival and periodontal ligament tissues could inhibit differentiation and promote the proliferation, invasion, and migration of OSCC both in vitro and in vivo. Furthermore, microarray data suggested that genes, such as CDK1, BUB1B, TOP2A, DLGAP5, BUB1, and CCNB2, probably play a role in influencing the different effects of gingival stromal tissue cells (G-SCs) and periodontal ligament stromal cells (P-SCs) on the progression of OSCC. Therefore, both G-SCs and P-SCs could promote the progression of OSCC, which could be a potential regulatory mechanism in the progression of OSCC. Normal stromal cells surrounding the tumor parenchyma, such as the extracellular matrix (ECM), normal fibroblasts, mesenchymal stromal cells, and osteoblasts, play a significant role in the progression of cancers. However, the role of gingival and periodontal ligament tissue-derived stromal cells in OSCC progression is unclear. In this study, the effect of G-SCs and P-SCs on the differentiation, proliferation, invasion, and migration of OSCC cells in vitro was examined by Giemsa staining, Immunofluorescence (IF), (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS), invasion, and migration assays. Furthermore, the effect of G-SCs and P-SCs on the differentiation, proliferation, and bone invasion by OSCC cells in vivo was examined by hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), and tartrate-resistant acid phosphatase (TRAP) staining, respectively. Finally, microarray data and bioinformatics analyses identified potential genes that caused the different effects of G-SCs and P-SCs on OSCC progression. The results showed that both G-SCs and P-SCs inhibited the differentiation and promoted the proliferation, invasion, and migration of OSCC in vitro and in vivo. In addition, genes, including CDK1, BUB1B, TOP2A, DLGAP5, BUB1, and CCNB2, are probably involved in causing the different effects of G-SCs and P-SCs on OSCC progression. Therefore, as a potential regulatory mechanism, both G-SCs and P-SCs can promote OSCC progression

Crosstalk between cancer and different cancer stroma subtypes promotes the infiltration of tumor‑associated macrophages into the tumor microenvironment of oral squamous cell carcinoma

Tumor‑associated macrophages (TAMs) are linked to the progression of numerous types of cancer. However, the effects of the tumor microenvironment (TME) of oral squamous cell carcinoma (OSCC), particularly the cancer stroma on TAMs, remains to be elucidated. In the present study, the effects of verrucous SCC‑associated stromal cells (VSCC‑SCs), SCC‑associated stromal cells (SCC‑SCs) and human dermal fibroblasts (HDFs) on the differentiation, proliferation and migration of macrophages in vitro was assayed using Giemsa staining, and immunofluorescence, MTS and Transwell (migration) assays, respectively. The combined results suggested that both VSCC‑SCs and SCC‑SCs promoted the differentiation of macrophages into M2 type TAMs, as well as the proliferation and migration of macrophages following crosstalk with HSC‑3 cells in vitro. Moreover, the SCC‑SCs exerted a more prominent effect on TAMs than the VSCC‑SCs. Immunohistochemical staining was used to examine the expression of CD34, CD45, CD11b and CD163 to assay the effects of VSCC‑SCs, SCC‑SCs and HDFs on microvessel density (MVD) and the infiltration of CD45(+) monocytes, CD11b(+) TAMs and CD163(+) M2 type macrophages. The results suggested that both VSCC‑SCs and SCC‑SCs promoted MVD and the infiltration of CD45(+) monocytes, CD11b(+) TAMs and CD163(+) M2 type TAMs into the TME of OSCC following crosstalk with HSC‑3 cells in vivo. The SCC‑SCs exerted a more prominent promoting effect than the VSCC‑SCs. Finally, the potential genes underlying the differential effects of VSCC‑SCs and SCC‑SCs on the infiltration of TAMs were investigated using microarray analysis. The results revealed that interleukin 1β, bone morphogenetic protein 4, interleukin 6 and C‑X‑C motif chemokine ligand 12 had great potential to mediate the differential effects of VSCC‑SCs and SCC‑SCs on TAM infiltration. On the whole, the findings presented herein, demonstrate that both VSCC‑SCs and SCC‑SCs promote the infiltration of TAMs into the TME of OSCC following crosstalk with HSC‑3 cells; the SCC‑SCs were found to exert a more prominent promoting effect. This may represent a potential regulatory mechanism for the infiltration of TAMs into the TME of OSCC

Preparation of Absorption-Resistant Hard Tissue Using Dental Pulp-Derived Cells and Honeycomb Tricalcium Phosphate

In recent years, there has been increasing interest in the treatment of bone defects using undifferentiated mesenchymal stem cells (MSCs) in vivo. Recently, dental pulp has been proposed as a promising source of pluripotent mesenchymal stem cells (MSCs), which can be used in various clinical applications. Dentin is the hard tissue that makes up teeth, and has the same composition and strength as bone. However, unlike bone, dentin is usually not remodeled under physiological conditions. Here, we generated odontoblast-like cells from mouse dental pulp stem cells and combined them with honeycomb tricalcium phosphate (TCP) with a 300 mu m hole to create bone-like tissue under the skin of mice. The bone-like hard tissue produced in this study was different from bone tissue, i.e., was not resorbed by osteoclasts and was less easily absorbed than the bone tissue. It has been suggested that hard tissue-forming cells induced from dental pulp do not have the ability to induce osteoclast differentiation. Therefore, the newly created bone-like hard tissue has high potential for absorption-resistant hard tissue repair and regeneration procedures

Impact of the Stroma on the Biological Characteristics of the Parenchyma in Oral Squamous Cell Carcinoma

Solid tumors consist of the tumor parenchyma and stroma. The standard concept of oncology is that the tumor parenchyma regulates the tumor stroma and promotes tumor progression, and that the tumor parenchyma represents the tumor itself and defines the biological characteristics of the tumor tissue. Thus, the tumor stroma plays a pivotal role in assisting tumor parenchymal growth and invasiveness and is regarded as a supporter of the tumor parenchyma. The tumor parenchyma and stroma interact with each other. However, the influence of the stroma on the parenchyma is not clear. Therefore, in this study, we investigated the effect of the stroma on the parenchyma in oral squamous cell carcinoma (OSCC). We isolated tumor stroma from two types of OSCCs with different invasiveness (endophytic type OSCC (ED-st) and exophytic type OSCC (EX-st)) and examined the effect of the stroma on the parenchyma in terms of proliferation, invasion, and morphology by co-culturing and co-transplanting the OSCC cell line (HSC-2) with the two types of stroma. Both types of stroma were partially positive for alpha-smooth muscle actin. The tumor stroma increased the proliferation and invasion of tumor cells and altered the morphology of tumor cells in vitro and in vivo. ED-st exerted a greater effect on the tumor parenchyma in proliferation and invasion than EX-st. Morphological analysis showed that ED-st changed the morphology of HSC-2 cells to the invasive type of OSCC, and EX-st altered the morphology of HSC-2 cells to verrucous OSCC. This study suggests that the tumor stroma influences the biological characteristics of the parenchyma and that the origin of the stroma is strongly associated with the biological characteristics of the tumor

Geometrical Structure of Honeycomb TCP to Control Dental Pulp-Derived Cell Differentiation

Recently, dental pulp has been attracting attention as a promising source of multipotent mesenchymal stem cells (MSCs) for various clinical applications of regeneration fields. To date, we have succeeded in establishing rat dental pulp-derived cells showing the characteristics of odontoblasts under in vitro conditions. We named them Tooth matrix-forming, GFP rat-derived Cells (TGC). However, though TGC form massive dentin-like hard tissues under in vivo conditions, this does not lead to the induction of polar odontoblasts. Focusing on the importance of the geometrical structure of an artificial biomaterial to induce cell differentiation and hard tissue formation, we previously have succeeded in developing a new biomaterial, honeycomb tricalcium phosphate (TCP) scaffold with through-holes of various diameters. In this study, to induce polar odontoblasts, TGC were induced to form odontoblasts using honeycomb TCP that had various hole diameters (75, 300, and 500 mu m) as a scaffold. The results showed that honeycomb TCP with 300-mu m hole diameters (300TCP) differentiated TGC into polar odontoblasts that were DSP positive. Therefore, our study indicates that 300TCP is an appropriate artificial biomaterial for dentin regeneration

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

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

Secretory Carcinoma of Salivary Gland with High-Grade Histology Arising in Hard Palate: A Case Report

Secretory carcinoma (SC) is a recently described salivary gland tumor reported in the fourth edition of World Health Organization classification of head and neck tumors. SC is characterized by strong S-100 protein, mammaglobin, and vimentin immunoexpression, and harbors a t(12;15)(p13;q25) translocation which leads to ETV6-NTRK3 fusion product. Histologically, SC displays a lobulated growth pattern and is often composed of microcystic, tubular, and solid structures with abundant eosinophilic homogenous or bubbly secretion. SC is generally recognized as low-grade malignancy with low-grade histopathologic features, and metastasis is relatively uncommon. In this case, we described a SC of hard palate that underwent high grade transformation and metastasis to the cervical lymph node in a 54-year-old patient. In addition, this case showed different histological findings between primary lesion and metastasis lesion. Therefore, the diagnosis was confirmed by the presence of ETV6 translocation. Here, we report a case that occurred SC with high-grade transformation in the palate, and a review of the relevant literature is also presented

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

The cancer stroma regulates bone invasion in oral squamous cell carcinoma (OSCC). However, data on normal stroma are limited. In the present study, the effects of gingival and periodontal ligament tissue‑derived stromal cells (G‑SCs and P‑SCs, respectively) and human dermal fibroblasts (HDFs) on bone resorption and osteoclast activation were assessed using hematoxylin and eosin and tartrate‑resistant acid phosphatase staining in a cell line‑derived xenograft model. The results demonstrated that G‑SCs promoted bone invasion and osteoclast activation and inhibited osteoclast proliferation following crosstalk with the human OSCC HSC‑3 cell line, whereas P‑SCs inhibited bone resorption and promoted osteoclast proliferation in vitro but had a minimal effect on osteoclast activation both in vitro and in vivo following crosstalk with HSC‑3 cells. Furthermore, the effects of G‑SCs, P‑SCs and HDFs on protein expression levels of matrix metalloproteinase (MMP)‑9, membrane type 1 MMP (MT1‑MMP), Snail, parathyroid hormone‑related peptide (PTHrP) and receptor activator of NF‑κB ligand (RANKL) in HSC‑3 cells in OSCC bone invasion regions were assessed using immunohistochemistry. The results demonstrated that G‑SCs had a more prominent effect on the expression of MMP‑9, MT1‑MMP, Snail, PTHrP, and RANKL, whereas P‑SCs only promoted RANKL and PTHrP expression and exerted a minimal effect on MMP‑9, MT1‑MMP and Snail expression. The potential genes underlying the differential effects of G‑SCs and P‑SCs on bone invasion in OSCC were evaluated using a microarray, which indicated that cyclin‑dependent kinase 1, insulin, aurora kinase A, cyclin B1 and DNA topoisomerase II alpha underlaid these differential effects. Therefore, these results demonstrated that G‑SCs promoted bone invasion in OSCC by activating osteoclasts on the bone surface, whereas P‑SCs exerted an inhibitory effect. These findings could indicate a potential regulatory mechanism for bone invasion in OSCC