Clinical significance of integrin αV and ß superfamily members and focal adhesion kinase activity in oral squamous cell carcinoma: a retrospective observational study.

Objectives: Integrins are heterodimeric transmembrane plasma membrane proteins composed of α- and ß-chains. They bind to extracellular matrix (ECM) and cytoskeletal proteins as ECM protein receptors. Upon ECM protein binding, integrins activate focal adhesion kinase (FAK) and transduce various signals. Despite their importance, integrin and FAK expression in oral squamous cell carcinoma (OSCC) tissue and the prognosis of patients with OSCC remains elusive. Methods: In a retrospective observational study, we immunohistochemically evaluated integrin αV, ß1, ß3, ß5, ß6, FAK, and phosphorylated-FAK (pFAK) expressions as prognostic predictors in 96 patients with OSCC. Patients were classified as positive or negative based on staining intensity, and clinicopathologic characteristics and survival rates of the two groups were compared. The association between above integrin-related proteins and PD-1 or PD-L1 in OSCC tissues was investigated. Results: We observed immunohistochemical integrin αV, ß1, ß6, ß8, and FAK expressions in the cell membrane and cytoplasm but not integrin ß3 and ß5 in the OSCC tissues. pFAK was expressed in the cytoplasm of OSCC cells. The overall survival rate significantly decreased in pFAK-positive OSCC patients compared to the negative group, and cervical lymph node metastasis significantly increased in integrin ß8-positive patients with OSCC (p < 0.05). No association between integrin-related proteins and PD-1 or PD-L1 in OSCC tissues was observed. Conclusion: Our results indicate that pFAK and integrin ß8 are prognostic factors for OSCC. Therefore, pFAK- and integrin ß8-targeting new oral cancer diagnostic and therapeutic methods hold a promising potential.

Interaction of Integrin αvß8 With Type I Collagen Promotes Squamous Cell Carcinoma Cell Motility via RAC1 Activation.

BACKGROUND/AIM: The interaction of integrin αvß8 with type I collagen was shown to promote oral squamous cell carcinoma (SCC) cell proliferation via the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. However, the role of integrin αvß8 in SCC progression remains poorly understood. In this study, the role of integrin αvß8 in oral SCC progression was therefore investigated. MATERIALS AND METHODS: Integrin αv and ß8 protein expression in oral SCC cells was examined by western blotting. Oral SCC cell motility was investigated using modified Boyden chamber assays. Behavior of oral SCC cells was examined in three-dimensional culture using type I collagen gel. Ras homolog family member A (RHOA), Ras-related C3 botulinum toxin substrate 1 (RAC1), and cell division control protein 42 homolog (CDC42) activity of oral SCC cells was analyzed by pull-down assays. RESULTS: SCC cells with high integrin αvß8 expression levels had a high ability to migrate on type I collagen and exhibited enhanced invasion into type I collagen gel. In SCC cells with high integrin αvß8 expression level, cultivation on type I collagen induced RAC1 activation. Treatment with RAC1 inhibitor reduced type I collagen-induced motility of SCC cells. Down-regulation of integrin ß8 by specific antisense oligonucleotide reduced type I collagen-induced RAC1 activation and suppressed cell motility and invasion into type I collagen gel. CONCLUSION: The interaction of integrin αvß8 with type I collagen facilitates SCC cell motility and invasion via RAC1 activation. Therefore, integrin αvß8 and RAC1 may represent new targets for inhibiting metastasis and invasion in patients with oral SCC.

Suture granulomas developing after the treatment of oral squamous cell carcinoma.

INTRODUCTION: Suture granuloma is a benign tumor that develops because of the presence of surgical suture materials. It commonly occurs several years after different types of surgeries. Here we report a case involving a 64-year-old man who underwent head and neck surgery for oral squamous cell carcinoma and developed multiple suture granulomas mimicking tumor recurrence in the radiation field just a few days after the completion of adjuvant chemoradiation therapy. PRESENTATION OF CASE: The patient underwent surgery for lymph node metastasis in the neck at 6 months after the resection of primary oral squamous cell carcinoma. Fifteen days after the completion of adjuvant chemoradiation therapy at a total dose of 50 Gy, small nodules appeared in the radiation field, along the areas of the subcutaneous surgical sutures. Cancer recurrence was initially suspected, but histopathological analysis of a biopsy specimen confirmed foreign body granuloma. DISCUSSION: Chemoradiation therapy may enhance the immunoreaction of macrophages in the radiation field and promote the formation of granulation tissue in a short period of time. In addition, cisplatin, which was concurrently administered with radiation in our case, could have influenced the development of the suture granuloma. CONCLUSION: In addition to tumor recurrence, suture granulomas should be considered a differential diagnosis for nodules occurring after surgery, even if they develop in the field of radiation.

Management of an Internal Carotid Artery Injury Caused by a Displaced Titanium Plate With a Combination of Interventional Vascular Radiology and Surgery.

Treatment of pseudoaneurysms in the internal carotid artery (ICA) is associated with a high risk of cerebral infarction; therefore, vessel ligation for hemostasis must be avoided. A 66-year-old man had intraoral hemorrhaging. At the time of the initial examination, computed tomography angiography showed jaw plate displacement near the ICA. A more detailed image was obtained using digital-subtraction angiography. After evaluation of the image, a pseudoaneurysm was diagnosed. Six days later, there were concerns about aspiration and airway obstruction; therefore, tracheostomy was performed. Interventional vascular radiology (IVR) and surgery were planned to facilitate complete recovery, removal of the jaw plate, and repair of the pseudoaneurysm. Before surgery, it was confirmed that it would be possible to block blood flow for approximately 20 minutes. Surgery was performed with the patient under general anesthesia. Before plate removal, cardiovascular surgeons exposed the left large saphenous vein and prepared it so that it could be used to patch the vascular wall defect. A balloon type of embolic protection device was placed so that it could be inflated at any time after plate removal via oral surgery. The pseudoaneurysm was found directly under the plate; however, it had adhered to the scar tissue. As removal progressed, hemorrhaging occurred. To achieve hemostasis, the balloon embolic protection device was inflated. The pseudoaneurysm was removed, and a red thrombus was aspirated. On postoperative day 41, bleeding reoccurred. Two days later, embolization using a platinum coil and stent placement were performed through IVR monotherapy. Postoperative progress was favorable, and the patient was discharged 83 days after treatment without neurologic sequelae. ICA pseudoaneurysms located near the skull base are risky and challenging to repair. However, for traumatic aneurysms such as the one in this case, a combination of IVR therapy and surgery is useful for controlling intraoperative hemorrhage.

Overexpression of FGF9 in prostate epithelial cells augments reactive stroma formation and promotes prostate cancer progression.

Bone metastasis is the major cause of morbidity and mortality of prostate cancer (PCa). Fibroblast growth factor 9 (FGF9) has been reported to promote PCa bone metastasis. However, the mechanism by which overexpression of FGF9 promotes PCa progression and metastasis is still unknown. Herein, we report that transgenic mice forced to express FGF9 in prostate epithelial cells (F9TG) developed high grade prostatic intraepithelial neoplasia (PIN) in an expression level- and time-dependent manner. Moreover, FGF9/TRAMP bigenic mice (F9TRAMP) grew advanced PCa earlier and had higher frequencies of metastasis than TRAMP littermates. We observed tumor microenvironmental changes including hypercellularity and hyperproliferation in the stromal compartment of F9TG and F9TRAMP mice. Expression of TGFß1, a key signaling molecule overexpressed in reactive stroma, was increased in F9TG and F9TRAMP prostates. Both in vivo and in vitro data indicated that FGF9 promoted TGFß1 expression via increasing cJun-mediated signaling. Moreover, in silico analyses showed that the expression level of FGF9 was positively associated with expression of TGFß1 and its downstream signaling molecules in human prostate cancers. Collectively, our data demonstrated that overexpressing FGF9 in PCa cells augmented the formation of reactive stroma and promoted PCa initiation and progression.

Type 2 Fibroblast Growth Factor Receptor Signaling Preserves Stemness and Prevents Differentiation of Prostate Stem Cells from the Basal Compartment.

Prostate stem cells (P-SCs) are capable of giving rise to all three lineages of prostate epithelial cells, which include basal, luminal, and neuroendocrine cells. Two types of P-SCs have been identified in both human and mouse adult prostates based on prostasphere or organoid cultures, cell lineage tracing, renal capsule implantation, and expression of luminal- and basal-specific proteins. The sphere-forming P-SCs are from the basal cell compartment that express P63, and are therefore designated as basal P-SCs (P-bSCs). Luminal P-SCs (P-lSCs) express luminal cytokeratins and Nkx3.1. Herein, we report that the type 2 FGF receptor (FGFR2) signaling axis is crucial for preserving stemness and preventing differentiation of P-bSCs. FGFR2 signaling mediated by FGFR substrate 2α (FRS2α) is indispensable for formation and maintenance of prostaspheres derived from P63(+) P-bSCs. Ablation of Fgfr2 in P63(+) cells in vitro causes the disintegration of prostaspheres. Ablation of Fgfr2 in vivo reduces the number of P63-expressing basal cells and enriches luminal cells. This suggests a basal stem cell-to-luminal cell differentiation. In addition, ablation of Fgfr2 in P63(+) cells causes defective postnatal development of the prostate. Therefore, the data indicate that FGFR2 signaling is critical for preserving stemness and preventing differentiation of P-bSCs.

Prostate Sphere-forming Stem Cells Are Derived from the P63-expressing Basal Compartment.

Prostate stem cells (P-SCs) are capable of giving rise to all three lineages of prostate epithelial cells, including basal, luminal, and neuroendocrine cells. Multiple methods have been used to identify P-SCs in adult prostates. These include in vivo renal capsule implantation of a single epithelial cell with urogenital mesenchymal cells, in vitro prostasphere and organoid cultures, and lineage tracing with castration-resistant Nkx3.1 expression (CARN), in conjunction with expression of cell type-specific markers. Both organoid culture and CARN tracing show the existence of P-SCs in the luminal compartment. Although prostasphere cells predominantly express basal cell-specific cytokeratin and P63, the lineage of prostasphere-forming cells in the P-SC hierarchy remains to be determined. Using lineage tracing with P63(CreERT2), we show here that the sphere-forming P-SCs are P63-expressing cells and reside in the basal compartment. Therefore we designate them as basal P-SCs (P-bSCs). P-bSCs are capable of differentiating into AR(+) and CK18(+) organoid cells, but organoid cells cannot form spheres. We also report that prostaspheres contain quiescent stem cells. Therefore, the results show that P-bSCs represent stem cells that are early in the hierarchy of overall prostate tissue stem cells. Understanding the contribution of the two types of P-SCs to prostate development and prostate cancer stem cells and how to manipulate them may open new avenues for control of prostate cancer progression and relapse.

Induction of alpha2-antiplasmin inhibits E-cadherin processing mediated by the plasminogen activator/plasmin system, leading to suppression of progression of oral squamous cell carcinoma via upregulation of cell-cell adhesion.

The plasminogen activator/plasmin system is one of the main protease systems involved in tumor cell invasion and metastasis. Our previous study has shown that plasmin degrades E-cadherin and promotes cell dissemination by downregulation of E-cadherin-mediated cell-cell adhesion in oral squamous cell carcinoma (SCC) cells. To examine the effect of downregulation of the plasminogen activator/plasmin system by alpha2-antiplasmin (alpha2-AP) on cell-cell adhesion mediated by E-cadherin in oral SCC cells, the oral SCC cell line SCCKN was stably transfected with alpha2-AP cDNA. Induction of alpha2-AP expression led to the inhibition of the proteolysis of E-cadherin by plasminogen activator/plasmin in SCC cells, resulting in the enhancement of the cell aggregation and the suppression of the cell motility. Moreover, alpha2-AP also reduced the ability of SCC cells to invade type I collagen gel, and suppressed tumorigenicity in vivo. These results suggested that downregulation of the plasminogen activator/ plasmin system by alpha2-AP might be a potent therapeutic approach to prevent the progression of oral SCC.

Plasminogen activator/plasmin system suppresses cell-cell adhesion of oral squamous cell carcinoma cells via proteolysis of E-cadherin.

The participation of plasminogen activator/plasmin system in the expression and function of E-cadherin was examined in oral squamous cell carcinoma (SCC) cells. Treatment of SCC cells with plasminogen reduced the Ca2+-dependent cell aggregation. SCC cells expressed E-cadherin at the cell membrane, and released a small amount of soluble E-cadherin at 80 kDa in the culture medium. Addition of plasminogen to SCC cells led to a decrease in the amount of E-cadherin of the cell membrane and the enhancement of the shedding of E-cadherin ectodomain. Plasmin directly cleaved E-cadherin of SCC cells and enhanced the motility of SCC cells. These results suggested that plasminogen activator/plasmin system might directly mediate the proteolytic processing of E-cadherin in oral SCC cells and that might facilitate the progression of oral SCC by downregulation of E-cadherin-mediated cell-cell adhesion.

Role of stromal thrombospondin-1 in motility and proteolytic activity of oral squamous cell carcinoma cells.

The immunohistochemical localization of thrombospondin-1 (TSP-1) in human normal oral mucosa and oral squamous cell carcinoma (SCC) was examined. The immunostaining of TSP-1 was mainly localized in the connective tissues adjacent to the epithelium of oral mucosa, whereas epithelial cells showed negligible immunoreactivity for TSP-1. TSP-1 expression was striking in the stroma of SCC. TSP-1 synthesis by SCC cells and fibroblasts in culture was examined by immunoprecipitation with anti-TSP-1 antibody. Fibroblasts produced a large amount of TSP-1, whereas SCC cells secreted little amount of TSP-1. Treatment of fibroblasts by the conditioned medium of SCC cells led to an increase in TSP-1 synthesis. TSP-1 induced haptotactic migration and stimulated the production of matrix metalloproteinase-9 (MMP-9) in SCC cells. These results suggest that TSP-1 in the stroma of oral SCC might be synthesized by mesenchymal cells but not by epithelial cells, and that the synthesis of TSP-1 might be regulated by interaction with SCC cells. TSP-1 accumulated in the stroma might promote the progression of oral SCC by enhancing the motility and proteolytic activity in a paracrine manner.