Loss of maspin is a negative prognostic factor for invasion and metastasis in oral squamous cell carcinoma.

OBJECTIVE: Maspin, a 42-kDa protein, belongs to the serpin family of protease inhibitors and is known to have tumor-suppressor function. In this study, we investigated the interrelationship between clinicopathologic findings and maspin expression in oral squamous cell carcinoma (OSCC). METHODS: Using immunohistochemical techniques to examine the expression levels of maspin in OSCC, maspin expression in OSCC was detected in 46 (64.8%) of 71 cases. We also compared the clonicopathologic features of OSCC cases with maspin expression levels. Moreover, we examined expression of maspin in eight cell lines derived from OSCC using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. RESULTS: There was a significant correlation between decreased maspin expression and T-category (P < 0.01), lymph metastasis (P < 0.0001), and mode of invasion (P < 0.0001). Patients with positive maspin expression had a significantly better prognosis (P < 0.001). Lower expression of maspin was also seen in cell lines derived from grade 4D, which shows stronger invasive potential than other grades of OSCC. CONCLUSION: Maspin may be a useful marker to identify the potential for progression in OSCC.

Significance of stromal desmoplasia and myofibroblast appearance at the invasive front in squamous cell carcinoma of the oral cavity.

BACKGROUND: Tumor invasion involves complex interactions between tumor and stromal cells. We examined the extent of connective tissue in the tumor stroma and whether myofibroblasts play a role in assisting cancer invasion and metastasis. METHODS: Biopsy materials from 84 patients with oral squamous cell carcinoma (SCC) were used. We compared data from intrastromal collagen fibers using Azan staining, immunohistochemical identification of myofibroblasts by cytoskeletal markers, alpha-smooth muscle actin, vimentin, desmin, and clinicopathological parameters. Clinical outcome was compared by 5-year survival rate. RESULTS: There were high levels of stromal collagen fibers in invasive tumors. Myofibroblast appearance increased with increasing tumor invasiveness. Lymph node metastasis occurred more frequently in the myofibroblast-positive group, and the survival rate was significantly poorer in this group. CONCLUSIONS: Fibrous stroma in SCC appeared to have a desmoplastic response. However, an independent invasive mechanism may regulate the stroma, with tumor desmoplasia occurring in highly developed, invasive tumors.

Integrin expression levels correlate with invasion, metastasis and prognosis of oral squamous cell carcinoma.

The present study evaluated the relationship between alpha 3, alpha 6A, and beta 1 integrin expression in cancer cells at the invasive front of oral squamous cell carcinoma (OSCC) and survival rates, as well as the clinical and pathological characteristics. Sections of 100 specimens of primary OSCC were immunostained to assess alpha 3, alpha 6A, and beta 1 integrin expression in cancer cells at the invasive front. OSCC patients with higher expression levels of alpha 3, alpha 6A, and beta 1 integrin had significantly better prognosis than those with lower expression levels (median survival at low vs. high expression levels: alpha 3, 37.1 months vs. 55.7 months; alpha 6A , 38.3 months vs. 47.9 months; and beta 1, 26.1 months vs. 46.1 months) (P < 0.05). In addition, beta 1 integrin expression showed the highest correlation with clinical and pathological characteristics. This study concludes that alpha 3, alpha 6A, and beta 1 integrin expression in cancer cells at the invasive front are related to the mode of invasion and prognosis in OSCC.

Copper efflux transporter (ATP7B) contributes to the acquisition of cisplatin-resistance in human oral squamous cell lines.

Acquired resistance to cisplatin (CDDP) is an issue in cancer chemotherapy. This resistance has been reported to be correlated with the expression of the Cu influx copper transporter 1 (CTR1) and two copper efflux transporters (ATP7A, ATP7B). We investigated the correlation between the expression of these transporters and the sensitivity to CDDP using three pairs of parent cell lines and resistant cell lines derived from various types of invasive oral squamous cell carcinoma (OSCC). Using multiple steps, each of the CDDP-resistant cell lines, HSC-4-R, OSC-19-R, HOC313-R, was selected from HSC-4 cells derived from a cancer with medium invasiveness, OSC-19 cells derived from a cancer with high invasiveness and HOC313 cells derived from a cancer with the highest invasiveness. Resistant cell lines had a stronger expression of ATP7B in conjunction with the acquisition of CDDP-resistance than parent cell lines. Furthermore, OSC-19-R cells transfected with the ATP7B siRNA had a 10.6-fold higher sensitivity to CDDP compared to OSC-19-R cells transfected with a nonsense siRNA. These results suggest that each of the resistant cell lines had acquired resistance to CDDP due to the overexpression of ATP7B. On the other hand, the expression of CTR1 was the same between sensitive cell lines and resistant cell lines and ATP7A mRNA expression was barely noted. We conclude that ATP7B is correlated with the acquisition of CDDP resistance more closely than either CTR1 or ATP7A. ATP7B may be a key determinant in the acquired resistance to CDDP in OSCC.

Expression of bone morphogenetic protein 2 and fibroblast growth factor 2 during bone regeneration using different implant materials as an onlay bone graft in rabbit mandibles.

OBJECTIVES: The purpose of this study was to histologically and immunohistochemically evaluate bone regeneration using 3 different implant materials in rabbit mandibles and to compare the bone regenerative capability of these materials in an animal model. STUDY DESIGN: Adult male Japanese white rabbits (n = 48; 12-16 wks old; 2.5-3.0 kg) were divided into 4 groups, consisting of 12 animals each. The implant materials were beta-tricalcium phosphate (beta-TCP), autologous bone derived from the radius, and recombinant human bone morphogenetic protein 2 (rhBMP-2) with polylactic acid/polyglycolic acid copolymer and gelatin sponge (PGS) complex. After incising along the inferior border of the mandible, the materials were implanted as only grafts and covered by titanium mesh with screws. No material was implanted into the control group. The rabbits were killed at 2, 4, 8, 12, and 24 wks postoperatively, and formalin-fixed specimens containing titanium mesh were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immunohistochemical analysis, the specimens were treated with BMP-2 and fibroblast growth factor 2 (FGF-2) antibodies. Finally, they were examined microscopically. RESULTS: The autologous bone induced substantially more new bone formation compared with beta-TCP at 4 wks postoperatively. However, rhBMP-2/PGS induced new bone formation at 8 wks postoperatively. No growth of bony tissue was observed in the control group at any period. In the autologous bone and rhBMP-2/PGS groups, both BMP-2 and FGF-2 were observed later in the beta-TCP group than in other groups. CONCLUSION: This study suggests that autologous bone as well as rhBMP-2/PGS implants induce expression of both BMP-2 and FGF-2 specifically at the operated sites, even at early stages.

Targeting urokinase-type plasminogen activator and its receptor for cancer therapy.

Cancer invasion and metastasis are highly complex processes and a serine protease urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system has been postulated to play a central role in the mediation of cancer progression. Of note, malignant tumor urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor levels have been found to vary considerably, and to be related to patient prognosis. In mouse models, the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system has been studied extensively as a target for anticancer therapy using a variety of approaches. In this review, we discuss the advances in the various modalities that have been used to target the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system, including protein-based and peptide-based drugs, antisense therapy, and RNA interference technology. In particular, preclinical mouse model studies that used human tumor xenografts are reviewed.