Mechanism of induction of apoptosis by radicals and enhancement of antitumor activity of anticancer drugs and irradiation in head and neck cancer

报道了与甲状腺功能障碍相关的甲状腺组织超氧化物歧化酶含量的变化。本研究发现，给予TSH的大鼠甲状腺组织和添加TSH的大鼠甲状腺细胞中的Mn-SOD含量增加。此外，在MTU抑制T3和T4合成而导致血清TSH水平升高的大鼠甲状腺中，随着TSH浓度的增加，大鼠甲状腺组织中的Mn-SOD含量也随之增加。在培养的甲状腺细胞中，由TSH引起的Mn-SOD含量的升高可被C-激酶抑制剂H17所抑制。提示TSH可诱导甲状腺细胞产生超氧化物歧化酶，并提示C-激酶在此过程中的作用，提示甲状腺功能不全患者血清TSH水平与细胞内超氧化物歧化酶含量的变化有密切关系。一些恶性肿瘤对由自由基介导的抗肿瘤作用的肿瘤坏死因子-α或几种抗肿瘤药物具有耐药性。一个Predical…这一反应的更多原因是体内一种酶--锰-超氧化物歧化酶的诱导，它能清除由肿瘤坏死因子-α产生的氧自由基。在本研究中，我们研究了抑制这种诱导是否恢复了肿瘤坏死因子-α的抗肿瘤作用。本实验采用B16-黑色素瘤BL6细胞株。用抗锰-超氧化物歧化酶抗体(大阪医科大学谷口教授提供的锰-超氧化物歧化酶抗体)用酶联免疫吸附试验测定锰-超氧化物歧化酶的含量。按NBT法测定锰-超氧化物歧化酶活性。在含有肿瘤坏死因子-α的培养液中培养的B16-黑色素瘤BL6细胞株中，没有出现死亡细胞，从而表明没有任何对细胞生长的影响。加入肿瘤坏死因子-α或TPA后，BL6细胞中的锰-超氧化物歧化酶浓度和活性均显著升高，提示肿瘤坏死因子-α和TPA可诱导BL6细胞产生锰-超氧化物歧化酶。H7的加入抑制了这种诱导作用。在加入H7后进一步加入肿瘤坏死因子-α可导致50.3%的BL6细胞死亡。提示C-K可能部分与Mn-SOD的诱导密切相关，抑制C-K可恢复肿瘤坏死效应。已有报道称，自由基在辐射或肿瘤坏死因子诱导肿瘤细胞凋亡中起一定作用。然而，身体里有这些激进分子的清道夫。在本研究中。我们试图研究这些清除剂，特别是清除氧自由基的细胞质铜锌超氧化物歧化酶(铜，锌-超氧化物歧化酶)的抑制是否会诱导细胞凋亡。本实验采用HL60细胞株。用DDC抑制铜、锌超氧化物歧化酶活性，用NBT法测定超氧化物歧化酶活性。用荧光素-荧光素酶法测细胞内三磷酸腺苷水平。DCFH法检测细胞内活性氧，光镜下观察细胞内有无凋亡小体形成，琼脂糖凝胶电泳法检测DNA片段化，证实细胞凋亡。管理较少

Alterations in the SOD content of thyroid tissues occurring in association with thyroid dysfunction were reported. In this study, the Mn-SODcontent was found to increase in thyroid tissues of rats administered TSHand in thyrocytes cultured in medium supplemented with TSH.Furthermore, in the thyroid glands of rats whose serum TSH level was elevated by inhibiting the synthesis of T3 and T4 levels by MTU, the Mn-SOD increased as the TSH concentration increased.In the cultured thyrocytes, the increase in Mn-SOD induced by TSH was inhibited by the C-kinase inhibitor, H17. These findings suggested the induction of Mn-SOD by TSH in the thyroid cells and pointed to a role of C-kinase in this process, thereby indicating that a close relationship exits between the serum TSH level and the change in Mn-SOD content in thyrocytes with thyroid dysfunction. Some malignant tumors are resistantto TNF-alpha or several antineoplastic agents which exert antiturnoral effects mediated by radicals. One predic … More ted reason for this restance is induction of an in vivo enzyme, Mn-SOD, which scavenges O^2. radicals generated by TNF-alpha. In the present study, we investigated whether or not inhibition of this induction recovers the antitumoral effects of TNF-alpha. B 16-melanoma BL6 cell strain was used in this experiments. Mn-SOD content was measured by ELISA using anti-Mn-SOD antibodies (Prof. Taniguchi, Osaka Univ Sch of Med, provided us the Mn-SOD antibodies). Mn-SOD activity was measured according to NBT method. In the B16-melanoma BL6 cell strain cultivated in a medium containing TNF-alpha, there were no deadcells, thereby showing the absence of any influence of the cell growth. Addition of TNF-alpha or TPA significantly increased both the concentration and activity of Mn-SOD, which indicated the induction of Mn-SOD by TNF-alpha and TPA in the BL6 cells. This induction was inhibitedby the addition of H7. Further addition of TNF-alpha after the addition of H7 caused cell death in 50.3% of the BL6 cells. This suggested that C-k inaseybe closely related to the induction of Mn-SOD in part and that the inhibition of C-kinase would recover the tumor necrotizing effect of TNF-alpha .It has been reported that radicals play some role in the induction of apoptosis by irradiation orTNF-alpha. However, the body has scavengers of these radicals. In the present study. we attempted to investigate whether or not inhibition of these scavengers, particularly of cytoplasmic copper, zinc-superoxide dsmutase (Cu, Zn-SOD) that scavenge oxygen radicals induces apoptosis. HL60 cell strain was used in this experiments. DDCwas used to inhibit Cu, Zn-SOD.SODactivities were measured according to NBT method. Cellular ATP levels were determined by luciferin-luciferase method. Intracellular reactive oxygen species were detected by DCFH method Apoptosis was confirmed by the formation of an apoptotic body observed by light microscopy and fragmentation of DNA detected by agarose gel electrophoresis. Admi Less