| Objective:The primary laryngeal squamous cell carcinoma is the most common (90%) tumor of primary site in the larynx. Treatment of laryngeal cancer, including surgery, radiotherapy and chemotherapy. According to the situation of diseases we can choose one or a combination of a variety of methods to treat it. Cyclooxygenase-2(COX-2), also as known as a key enzyme in the arachidonic acid synthesis of prostaglandin, has COX-1and COX-2two isozymes present in human body. A large number of studies have shown that high COX-2expression playing an important role in the pathogenesis of a variety of tumors in recent years. The present studies indicate that the role of COX-2in the pathogenesis of tumor through a variety of ways. Our pre-research has confirmed selective COX-2inhibitor nimesulide (NIM) can inhibit human laryngeal squamous cell carcinoma Hep-2cell xenografts in nude mice growing by inhibiting proliferation and inducing apoptosis. In this experiment, the impact of NIM on the angiogenesis(MVD), the expression of COX-2, Angiopoietin-2(Ang-2) and basic fibroblast growth factor (bFGF) in human laryngeal squamous cell carcinoma Hep-2cell xenografts in nude mice were tested in order to provide a theoretical basis for the treatment of laryngeal squamous cell carcinoma with MIM. Methods:In the pre-trial[1], human laryngeal squamous cell carcinoma Hep-2cells were inoculated in nude mice subcutaneously to establish xenograft model. Nude mice were randomly divided into experimental group and control group, the experimental group were intraperitoneal injected NIM (50mg/kg/2d,0.2ml); the control group were received intraperitoneal injection0.2ml saline.4weeks later, the mice were sacrificed and the tumors were obtained. In this experiment, immunohistochemical staining was used to detect CD31expression in laryngeal cancer in xenografts tissue intervened by NIM for positioning microvascular density (MVD) and the image analysis system was used for detecting the average optical density value. Then the differences between the two groups were compared. COX-2, Ang-2and bFGF protein expression were observed microscopically after assessed immunohistochemically. The average optical density values of COX-2, Ang-2and bFGF protein in xenogratts were analyzed by image analysis system. Reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression of COX-2, Ang-2and bFGF mRNA in xenografis, then the gray values were analyzed by Biod-rad softveares. Then the correlation between the expression of COX-2, Ang-2, bFGF and MVD were analyzed in the experimental group. Results:(1)Average MVD value were detected by immunohistochemistry SP method in xenografts in nude mice. The average MVD value of the experimental group was (12.83±3.06), significantly lower than that in the control group (25.50±4.85)(t=-5.412, P<0.05), showed that tumor angiogenesis reduced after selective COX-2inhibitors NIM intervened.(2)Immunohistochemistry SP method was used to detect the expression of COX-2, Ang-2and bFGF protein in xenograft tissues. COX-2protein optical density(38.12+15.56) in NIM treatment group was significantly decreased compared with the control group (140.92±23.12), the difference was statistically significant (t=-9.825, PO<0.05). The expression of Ang-2protein in NIM treatment group of was (49.02±7.67), the control group is (110.04±6.76), the difference between them was statistically significant (t=-14.607, P<0.05). The expression of bFGF protein(62.25±7.50) in NIM treatment group was significantly decreased compared to the control group (119.04±17.30), the difference was statistically significant (t=-7.391, P<0.05).(3)Gray value of COX-2mRNA detected by RT-PCR in NIM treatment group was (0.70±0.18), and the control group was (2.23±0.38), the difference was statistically significant (t=-9.825, P<0.05). Ang-2mRNA expression in the NIM treatment group was (0.49±0.03), the control group was (0.98±0.10), and the differences was statistically significant (t=-11.509, P<0.05). In NIM treatment group the bFGF mRNA expression was (0.65±0.08), the control group was (1.19±0.19), the differences was also statistically significant (t=-6.209, P<0.05).(4)There was a correlation between the expression of COX-2, Ang-2, bFGF protein and MVD in the experimental group. Correlation coefficient r were0.832,0.944,0.844(all P<0.05). Conclusion:(1)The selective COX-2inhibitors NIM could inhibit angiogenesis of human laryngeal squamous cell carcinoma Hep-2cell xenografts in nude mice.(2)There were a line relationships between the expression of COX-2, Ang-2, bFGF protein and MVD in experimental group separately, the relationship between the latter two angiogenesis promoting factors and MVD suggested that they played a significant role in tumor angiogenesis.(3)Because of the using of NIM, Ang-2and bFGF protein and mRNA expression decreased, indicating that the mechanism of angiogenesis inhibition in laryngeal squamous cell carcinoma Hep-2cell xenografts in nude mice by NIM may be related to the inhibition of the Ang-2and bFGF expression.(4)Selective COX-2inhibitor NIM can inhibit the growth of laryngeal squamous cell carcinoma Hep-2cell xenografts in nude mice by a variety of mechanisms, provides new ideas and means for the future comprehensive treatment of laryngeal squamous cell carcinoma... |
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