全反式维甲酸对甲状腺癌细胞形态及凋亡的影响

目的：观察全反式维甲酸(all-trans-retinoic acid，ATRA)体外诱导甲状腺癌细胞株的形态学变化和细胞凋亡。方法：分别以终浓度为0、10^-7、10^-6、10^-5、10^-4mol／L作用3种甲状腺癌细胞株(FTC-133、K1、8505C)，在倒置显微镜下观察细胞生长情况及形态特征变化；利用Annexin-V FITC／PI染色，荧光显微镜下观察细胞的凋亡。结果：ATRA作用后．FTC-133细胞与对照组比较．细胞排列较规整．呈梭形；对照组K1细胞成团生长，经维甲酸作用后细胞成团减少：8505C细胞经ATRA处理后．形态未见明显变化，但ATRA浓度为10^-4mol／L时可见细胞贴壁能力下降。ATRA在10^-5、10^-4mol/L时，FTC-133细胞凋亡率分别为(7．8±2．6)％和(11．6±3．7)％．K1细胞凋亡率分别为(7．9±2．6)％和(10．8±3．3)％、ATRA在10^-4mol/L时．8505C细胞凋亡率为(15．3±4．7)％，与对照组[(2．8±0．7)％、(3．1±0．9)％、(6．7±2．2)%]比较．差异均有统计学意义．P<0．05。结论：不同浓度的ATRA可诱导FTC-133、K1、8505C细胞形态学变化和细胞凋亡。     

二甲双胍对人滤泡状甲状腺癌细胞生长和能量代谢的影响

目的:观察不同浓度二甲双胍对人滤泡状甲状腺癌(follicular thyroid cancer,FTC）细胞增殖、凋亡及能量代谢的影响。方法:体外培养人FTC细胞(FTC-133),分为对照组和不同浓度二甲双胍处理组（1、3和10mmol/L）,分别培养24h、48h和72h。四甲基偶氮唑蓝（MTT）法检测细胞增殖,Annexin V-FITC/PI流式细胞术检测细胞凋亡,Seahorse能量代谢分析仪检测细胞糖酵解及线粒体呼吸的变化。结果:与对照组相比,二甲双胍抑制FTC-133增殖,随浓度及处理时间的增加,抑制效应加大,呈剂量-时间依赖性（P＜0.05）。二甲双胍诱导FTC-133凋亡,随浓度及处理时间的增加,其中晚期凋亡率明显增加,呈剂量-时间依赖性（P＜0.05）。二甲双胍可影响FTC-133糖代谢,与对照组相比,随二甲双胍浓度增加,糖酵解和线粒体呼吸可明显抑制,呈剂量-时间依赖性（P＜0.05）。结论:二甲双胍抑制FTC-133增殖并诱导凋亡,其机制可能是影响癌细胞能量代谢进而抑制其能量供应。     

^131I照射对分化型甲状腺癌细胞摄碘水平及NIS mRNA表达的影响

目的：探讨^131I不同时间照射后分化型甲状腺癌细胞摄取放射性碘（^131I）水平的变化以及检测是否影响NIS mRNA表达。方法：分化型乳头状甲状腺癌细胞株（GTHW3）培养在DMEM培养基中,应用同一活度（20μCi）的^131I对培养癌细胞进行不同时间（6h、12h、24h、48h）的照射。γ计数仪测定放射性碘（^131I）摄取率。采用RT—PCR法检测甲状腺癌细胞的NIS mRNA表达。结果：不同时间的放射性^131I照射使甲状腺癌细胞摄取^131I降低;凝胶电泳显示放射性^131I照射24h后GTHW3细胞NIS mRNA表达降低;照射组各时间点的^131I摄取率及24h和48h的NIS mRNA表达与未照射对照组比较均有显著性差异。结论：^131I照射可使DTC细胞的NIS mRNA表达降低,提示^131I照射致DTC细胞失分化及其摄碘能力降低可能与DTC细胞NIS mRNA表达降低有关。     

毛蕊异黄酮通过Nrf2/HO-1信号途径诱导人甲状腺癌FTC-133细胞发生铁死亡

目的:观察毛蕊异黄酮（CA）是否可诱导人甲状腺癌细胞系FTC-133细胞铁死亡并探讨其可能机制。方法: 采用RPMI 1640培养液培养FTC-133细胞,分为对照和CA、铁死亡抑制剂ferrostatin-1、血红素氧合酶-1（HO-1）激动剂CoPP、CA+ferrostatin-1和CA+CoPP组。CCK-8法检测细胞增殖。相应试剂盒检测细胞活性氧（ROS）、还原型谷胱甘肽（GSH）、丙二醛（MDA）、总铁和二价铁离子水平。Western Blot检测细胞中谷胱甘肽过氧化物酶4（GPX4）、铁蛋白重链1（FTH1）、核因子E2相关因子2（Nrf2）和HO-1蛋白表达。结果:与对照组比较,CA（50、100和150 μmol/L）处理在24 h、48 h和72 h三个时间点均降低细胞存活率,并呈现剂量依赖性（均P＜0.05）。与对照组比较,CA（50、100和150 μmol/L）处理48 h降低细胞中GSH的浓度（均P＜0.05）,增加了FTC-133细胞中ROS、MDA、总铁和二价铁离子浓度（均P＜0.05）。与对照组比较,CA（50、100和150 μmol/L）处理48 h显著降低细胞中GPX4（P＜0.05）和FTH1（P＜0.05）蛋白表达水平（均P＜0.05）。Ferrostatin-1部分逆转了CA诱导FTC-133细胞铁死亡的作用（均P＜0.05）。与对照组比较,CA（50、100和150 μmol/L）处理均降低Nrf2在细胞核中的表达及Nrf2在细胞核中表达与Nrf2总蛋白表达的比值（均P＜0.05）,而没有影响Nrf2总蛋白表达（均P＞0.05）。与对照组比较,CA（50、100和150 μmol/L）处理均降低细胞中HO-1的蛋白表达（均P＜0.05）。CoPP部分逆转了CA诱导FTC-133细胞铁死亡的作用（均P＜0.05）。结论:CA诱导了人甲状腺癌细胞系FTC-133细胞发生铁死亡,而其机制可能是通过Nrf2/HO-1信号通路。     

维甲酸联合曲古抑素对甲状腺癌细胞的诱导分化作用

背景与目的:维甲酸诱导甲状腺癌分化的有效率约30%,但其毒副作用限制了临床应用。两种以上诱导剂联合应用于肿瘤的分化,临床已开展了Ⅰ～Ⅲ期试验。但对维甲酸和组蛋白脱乙酰基酶的抑制剂的联合应用,未有报道。本试验初步研究全反式维甲酸(retinoic acid,RA)联合曲古抑素(trichostain A,TSA)诱导人乳头状甲状腺癌细胞株(K1)和人滤泡状甲状腺癌细胞株(FTC-133)的分化,增强诱导作用的效果,同时降低单一药物的毒副作用,为临床前期试验提供理论依据。方法:RA联合TSA,分为4种浓度,分别为1组RA1×10-4mol/L+TSA1.65×10-7mol/L、2组RA1×10-4mol/L+TSA3.31×10-7mol/L、3组RA1×10-5mol/L+TSA1.65×10-7mol/L、4组RA1×10-5mol/L+TSA3.31×10-7mol/L,在3个时间点(12、24、48h)处理两种细胞后,采用苏木精-伊红染色后,观察细胞生长的数量、形态;采用氮蓝四唑盐法(methythiazoly ltetrazolium,MTT)计算细胞生存率(survival rate,SR),研究联合药物对细胞的增殖、抑制和毒性作用;采用电化学发光法测定两种细胞株培养液中,甲状腺球蛋白(thyroglobulin,Tg)的水平,研究联合药物对肿瘤细胞的诱导分化作用。结果:联合药物作用K1和FTC-133后,细胞形态趋于规则,细胞间隔增大,细胞核明显缩小。4种浓度、3个时间点SR的方差分析,K1的F值分别为:23.52、170.14,FTC-133的F值分别为:57.09、224.35(P=0.000,均0.01),有统计学意义。SNK分析,SR由低到高的排列分别为:2组1组4组3组。4种浓度、3个时间点Tg方差分析,K1的F值分别为:69.63、101.07,FTC-133的F值分别为:79.77、81.72(P=0.000,均0.01),差异有统计学意义。LSD两两比较:K1和FTC-133的1组与3组比较,P分别为:0.06、0.2,0.05,两者之间差异无统计学意义,其他组均有统计学意义。结论:低浓度RA联合低浓度TSA,既可以抑制K1和FTC-133增殖,降低药物毒性作用,又可以增强对肿瘤细胞的诱导分化。其可能的机制是,TSA作用于转录步骤的DNA前调节,RA可能作用于转录步骤的信号后续调节,两种作用可能形成增强作用。通过转录后的传导系统,达到了抑制肿瘤细胞增殖和增强诱导分化的作用。     

全反式维甲酸与单纯疱疹病毒胸苷激酶基因对胶质瘤的协同杀伤作用

背景与目的：细胞间缝隙连接通讯（gap junctional intercellular communication,GJIC)是介导单纯疱疹病毒胸苷激酶（herpes simplx virus thymidine kinase,HSV-tk)基因治疗中旁观者效应的重要机制。全反式维甲酸(all-trans-retinotic acid,ATRA)或能通过上调胶质细胞GJIC和抑制肿瘤细胞生长的双重作用,促进HSV-tk基因治疗的疗效。本研究的目的在于证实HSV-tk和ATRA联合应用对胶质瘤细胞的协同杀伤作用。方法：分别以1μmol/L、10μmol/L、100μmol/L3种浓度的ARTA作用于培养的大鼠C6胶质瘤细胞,并研究ATRA对C6胶质瘤细胞分化、增殖、GJIC及connexin43(Cx43)基因转录等方面的影响。将C6细胞与稳定表达HSV-tk基因的C6tk细胞按不同比例混合,分别在含GCV和不同浓度ATRA或仅含GCV的培养基中培养,并于药物作用7天后用MTT法检测旁观者效应。结果：经3种浓度的ARTA作用后,C6胶质瘤细胞均显示出细胞分化的形态学特征。C6细胞的增殖也明显受到ATRA的抑制,绝大多数的活细胞都静止于G1期,100μmol/L ATRA对C6细胞增殖的抑制尤其明显,并诱导细胞凋亡。经3种浓度的ATRA分别作用后,C6细胞的GJIC也明显提高,而Cx43基因的转录未受明显影响。旁观者效应实验的结果显示,3种浓度的ATRA均可明显增强旁观者效应。结论：联合应用ATRA与HSV-TK基因治疗可以产生显著的杀伤胶质瘤细胞的作用。     

全反式维甲酸对甲状腺癌细胞形态及凋亡的影响

目的 :观察全反式维甲酸 (all trans retinoicacid ,ATRA)体外诱导甲状腺癌细胞株的形态学变化和细胞凋亡。方法 :分别以终浓度为 0、10 -7、10 -6、10 -5、10 -4mol/L作用 3种甲状腺癌细胞株(FTC 13 3、K1、85 0 5C) ,在倒置显微镜下观察细胞生长情况及形态特征变化 ;利用Annexin VFITC/PI染色 ,荧光显微镜下观察细胞的凋亡。结果 :ATRA作用后 ,FTC 13 3细胞与对照组比较 ,细胞排列较规整 ,呈梭形 ;对照组K1细胞成团生长 ,经维甲酸作用后细胞成团减少 ;85 0 5C细胞经ATRA处理后 ,形态未见明显变化 ,但ATRA浓度为 10 -4mol/L时可见细胞贴壁能力下降。ATRA在 10 -5、10 -4mol/L时 ,FTC 13 3细胞凋亡率分别为 ( 7 8± 2 6) %和( 11 6± 3 7) % ,K1细胞凋亡率分别为 ( 7 9±2 6) %和 ( 10 8± 3 3 ) %、ATRA在 10 -4mol/L时 ,85 0 5C细胞凋亡率为 ( 15 3± 4 7) % ,与对照组[( 2 8± 0 7) %、( 3 1± 0 9) %、( 6 7± 2 2 ) % ]比较 ,差异均有统计学意义 ,P <0 0 5。结论 :不同浓度的ATRA可诱导FTC 13 3、K1、85 0 5C细胞形态学变化和细胞凋亡。     

131I照射对分化型甲状腺癌细胞摄碘水平及NIS mRNA表达的影响

目的:探讨131I不同时间照射后分化型甲状腺癌细胞摄取放射性碘(125I)水平的变化以及检测是否影响NIS mRNA表达.方法:分化型乳头状甲状腺癌细胞株(GTHW3)培养在DMEM培养基中,应用同一活度(20μCi)的131I对培养癌细胞进行不同时间(6h、12h、24h、48h)的照射.γ计数仪测定放射性碘(125I)摄取率.采用RT-PCR法检测甲状腺癌细胞的NIS mRNA表达.结果:不同时间的放射性131I照射使甲状腺癌细胞摄取125I降低;凝胶电泳显示放射性131I照射24h后GTHW3细胞NIS mRNA表达降低;照射组各时间点的125I摄取率及24h和48h的NIS mRNA表达与未照射对照组比较均有显著性差异.结论:131I照射可使DTC细胞的NIS mRNA表达降低,提示131I照射致DTC细胞失分化及其摄碘能力降低可能与DTC细胞NIS mRNA表达降低有关.     

全反式维甲酸诱导人卵巢癌细胞凋亡的实验研究

目的：观察全反式维甲酸(A11一trans retinoic acid，ATRA)诱导人卵巢癌细胞CAOV3产生凋亡。方法：应用扫描电镜、透射电镜、DNA断裂分析及流式细胞术观察ATRA诱导人卵巢癌细胞CAOV3凋亡。结果：ATRA作用后电镜下细胞逐渐变圆，细胞表面微绒毛消失，核染色质更加致密，浓缩分块，胞质中有空泡形成，细胞表面出泡，脱落形成膜包裹的凋亡小体。流式细胞术不同浓度ATRA对CAOV3细胞凋亡作用的结果显示在DNA直方图上均出现低于G1期二倍体DNA含量的亚二倍体峰，随药物浓度增加，亚二倍体细胞从10^-8mol／L ATRA时的18．7％增加到10^-6mol／L的37．4％；10^-6mol／LATRA作用24h即诱导CAOV3细胞产生典型的梯形DNA条带(DNAlallder)，大小约180bp的整数倍递增，随ATRA作用时间延长而逐渐加强；结论：ATRA可以诱导卵巢癌细胞产生细胞凋亡，呈时间和浓度依赖性。     

miR-143-3p靶向KRAS阻滞PI3K/Akt信号通路抑制分化型甲状腺癌细胞增殖、侵袭和迁移

目的:探讨miR-143-3p对分化型甲状腺癌细胞增殖、侵袭和迁移的影响及其作用机制。方法:采用qRT-PCR检测miR-143-3p在30例分化型甲状腺癌组织和对应的癌旁组织,以及人分化型甲状腺癌细胞（TCP-1、FTC-133、SW579、BCPAP）和甲状腺滤泡上皮正常细胞（Nthy-ori3-1）中的表达水平。将miR-143-3p mimic和miR-143-3p mimic+pcDNA3.1-KRAS转染于FTC-133细胞中,采用CCK-8检测FTC-133细胞增殖活力;Transwell检测FTC-133细胞侵袭和迁移能力。双荧光素酶报告基因验证miR-143-3p和KRAS的靶向关系。Western blot检测蛋白的表达水平。结果:miR-143-3p在分化型甲状腺癌组织中的表达水平明显低于对应的癌旁组织。miR-143-3p在分化型甲状腺癌细胞系中的表达水平低于甲状腺滤泡上皮正常细胞的表达,尤其在FTC-133细胞中表达最低。过表达miR-143-3p显著抑制了FTC-133细胞增殖、侵袭和迁移能力。此外,双荧光素酶报告基因证实,KRAS为miR-143-3p的靶基因。进一步,过表达KRAS通过激活PI3K/Akt信号通路缓解了仅过表达miR-143-3p对FTC-133细胞增殖、侵袭和迁移能力的抑制作用。结论:过表达miR-143-3p通过靶向KRAS且阻滞PI3K/Akt信号通路,进而抑制分化型甲状腺癌细胞恶性生物学行为。     

The comparative effects of gene modulators on thyroid-specific genes and radioiodine uptake

The aim of this study was to comparatively investigate the effects of 5-azacytidine-C (5-Aza), trichostatin-A (TSA), and all-trans retinoic acid (ATRA) on mRNA expressions of Na/I symporter (NIS), thyroglobulin (Tg), thyroid peroxidase (TPO), and thyroid stimulating hormone receptor (TSH-R), and radioiodine (RAI) uptake in cancer (B-CPAP) and normal (Nthy-ori 3-1) thyroid cell lines. Cell lines were treated with 10 ng/mL of TSA, 5 microM of 5-Aza, and 1 microM of ATRA, according to the MTT (methyl-thiazol-tetrazolium) test results. Additionally, recombinant thyroid stimulating hormone (rTSH) was also applied, with a selected dose of 100 ng/mL. Following the treatment, NIS, Tg, TPO, and TSH-R mRNA levels were detected by real-time-polymerase chain reaction (RT-PCR) and RAI uptakes were measured by using a well counter as the counts/cell number. 5-Aza increased TSH-R mRNA expression in both of the cell lines and decreased TPO, NIS, and Tg mRNA levels in the cancer cell line. In the normal thyroid cell line, 5-Aza increased TPO mRNA levels 2-fold and made no differences in NIS and Tg mRNA levels. TSA treatment repressed NIS and Tg mRNA levels, and made no differences on other thyroid specific genes investigated in the cancer cell line. In the normal thyroid cell line, TSA increased TSH-R mRNA levels in 72 hours and created no important differences in other genes. ATRA repressed the TSH-R mRNA levels in the normal thyroid cell line and increased the TPO and Tg mRNA levels slightly in both cell lines. Furthermore, in short-term treatment, ATRA repressed NIS gene expression slightly, but in the long term, this repression turned to basal levels. 5-Aza, TSA, and ATRA did not make any differences in RAI uptake in the cancer cell line, but rTSH increased RAI uptake significantly. In the normal thyroid cell line, TSA and ATRA decreased RAI uptake (to 1/10 and 1/2, respectively), but 5-Aza and rTSH increased RAI uptake significantly (2- and 4-fold, respectively). We have shown an increase in TSH-R gene expression and radioiodine uptake with 5-Aza. Further in vitro and in vivo studies are needed to support our findings and the potential clinical use of this agent.     

The comparative effects of gene modulators on thyroid-specific genes and radioiodine uptake

The aim of this study was to comparatively investigate the effects of 5-azacytidine-C (5-Aza), trichostatin-A (TSA), and all-trans retinoic acid (ATRA) on the mRNA expressions of the sodium and iodine (Na/I) symporter (NIS), thyroglobulin (Tg), thyroid peroxidase (TPO), and the thyroid-stimulating hormone receptor (TSH-R), as well as radioiodine (RAI) uptake in cancer (B-CPAP) and normal (Nthy-ori 3-1) thyroid cell lines. Cell lines were treated with 10 ng/mL of TSA, 5 microM of 5-AZA, and 1 microM of ATRA, according to the MTT (methyl-thiazol-tetrazolium) test results. Additionally, recombinant thyroid-stimulating hormone (rTSH) was also applied, with a selected dose of 100 ng/mL. Following the treatment, NIS, Tg, TPO, and TSH-R mRNA levels were detected by real-time-polymerase chain reaction (RT-PCR) and RAI uptakes were measured by using a well counter as counts/cell number. 5-Aza increased TSH-R mRNA expression in both of the cell lines and decreased TPO, NIS, and Tg mRNA levels in the cancer cell line. In the normal thyroid cell line, 5-AZA increased TPO mRNA levels by 2-fold and made no differences in NIS and Tg mRNA levels. TSA treatment repressed NIS and Tg mRNA levels and made no change on other thyroid-specific genes that were investigated in the cancer cell line. In the normal thyroid cell line, TSA increased TSH-R mRNA levels in 72 hours and created no important difference in the other genes. ATRA repressed the TSH-R mRNA levels in the normal thyroid cell line and increased the TPO and Tg mRNA levels slightly in both the cell lines. Furthermore, in short-term treatment, ATRA repressed the NIS gene expression slightly, but in the long term, this repression turned to basal levels. 5-Aza, TSA, and ATRA did not make any changes in RAI uptake in the cancer cell line, but rTSH increased RAI uptake significantly. In the normal thyroid cell line, TSA and ATRA decreased RAI uptake (to 1/10 and 1/2, respectively), but 5-Aza and rTSH increased RAI uptake significantly (2- and 4-fold, respectively). In our study, we showed an increase in TSH-R gene expression and radioiodine uptake with 5-Aza. Further in vitro and in vivo studies are needed to support our findings and the potential clinical use of this agent.     

Ectopic expression of the thyroperoxidase gene augments radioiodide uptake and retention mediated by the sodium iodide symporter in non-small cell lung cancer

Radioiodide is an effective therapy for thyroid cancer. This treatment modality exploits the thyroid-specific expression of the sodium iodide symporter (NIS) gene, which allows rapid internalization of iodide into thyroid cells. To test whether a similar treatment strategy could be exploited in nonthyroid malignancies, we transfected non-small cell lung cancer (NSCLC) cell lines with the NIS gene. Although the expression of NIS allowed significant radioiodide uptake in the transfected NSCLC cell lines, rapid radioiodide efflux limited tumor cell killing. Because thyroperoxidase (TPO) catalyzes iodination of proteins and subsequently causes iodide retention within thyroid cells, we hypothesized that coexpression of both NIS and TPO genes would overcome this deficiency. Our results show that transfection of NSCLC cells with both human NIS and TPO genes resulted in an increase in radioiodide uptake and retention and enhanced tumor cell apoptosis. These findings suggest that single gene therapy with only the NIS gene may have limited efficacy because of rapid efflux of radioiodide. In contrast, the combination of NIS and TPO gene transfer, with resulting TPO-mediated organification and intracellular retention of radioiodide, may lead to more effective tumor cell death. Thus, TPO could be used as a therapeutic strategy to enhance the NIS-based radioiodide concentrator gene therapy for locally advanced lung cancer.     

ATRA对甲状腺鳞癌细胞生长及RARβ和p21mRNA表达的影响

目的：观察全反式维甲酸（ATRA）对甲状腺鳞癌SW579细胞株生长增殖及维甲酸受体β（RARβ）和p21表达的影响,进而探讨维甲酸的抗癌作用机制。方法：甲状腺鳞癌SW579细胞株经不同浓度ATRA作用48h后,在倒置显微镜下观察细胞生长情况及形态变化;MTT法测定细胞增殖活性;流式细胞仪检测细胞周期;RT-PCR方法检测细胞RARβ及p21 mRNA的表达。结果：随着ATRA的升高,SW579细胞的生长呈显著抑制状态,细胞生长滞留在G1期,RARβ和p21 mRNA表达水平均显著上调,呈剂量依赖性。结论：ATRA在一定浓度范围内对甲状腺鳞癌SW579细胞株有剂量依赖性的增殖抑制作用,其机制可能与提高细胞RARβ基因的表达、进而再上调p21的表达有关。     

In vivo radioiodide imaging and treatment of breast cancer xenografts after MUC1-driven expression of the sodium iodide symporter.

PURPOSE: Expression of the sodium iodide symporter (NIS) in the thyroid gland provides for effective imaging and treatment of thyroid cancer using radiolabeled iodide. Transfer of NIS into other tumors would expand the utility of this treatment to tumors of nonthyroid origin. MUC1 is a transmembrane glycoprotein that is overexpressed in many tumor types, including breast, pancreatic, and ovarian. The aim of this study was to create a construct containing NIS under the control of the MUC1 promoter to target expression specifically to MUC1-positive breast cancer cells. EXPERIMENTAL DESIGN: A replication-deficient adenoviral construct was created containing the MUC1 promoter followed by the human NIS gene. Iodide uptake assays, Western blot, and immunohistochemistry were used to confirm NIS expression and function. Breast cancer xenografts in mice were infected with Ad5/MUC1/NIS and then imaged and treated using radioiodide. RESULTS: A 58-fold increase in iodide uptake was observed in infected MUC1-positive T47D cells with no significant increase observed in MUC1-negative MDA-MB-231 cells or in cells infected with the control virus. The in vivo study yielded clear images of Ad/MUC1/NIS-infected tumor xenografts using (123)I. Administration of a therapeutic dose of (131)I resulted in an 83% reduction in tumor volume, whereas control tumors continued to increase in size (P < 0.01). CONCLUSIONS: These results show that the MUC1 promoter is capable of directing efficient and selective expression of the NIS gene in MUC1-positive breast tumor cells. This could potentially have applications for both imaging and therapy in a range of MUC1-positive tumor types.     

Biology and clinical application of the NIS gene

The sodium iodide symporter (NIS) is a plasma basolateral membrane protein that actively transports iodide to the thyroid follicular cells as the first step of thyroid hormone biosynthesis. NIS also mediates active iodide transport in other human tissues including the salivary glands, lactating mammary gland and gastric mucosa. NIS expression has been recently reported also in several other human tissues but its physiological role is still unclear. Cloning of the NIS gene and the development of specific NIS antibodies have allowed the characterization of the pathogenic role of NIS in thyroid cancer, thyroid autoimmune diseases, congenital hypothyroidism and other, non-thyroidal human diseases. The possibility to increase its levels of expression or to reinduce its expression in thyroid carcinomas that have lost the ability to take up radioiodine is one of the most promising clinically related fields of research. The recent discovery that more than 80% of human breast carcinomas endogenously express NIS protein has opened a very interesting new area of research into the possibility of using radioiodide in the diagnosis and treatment of breast cancer. In an attempt to make tumor cells susceptible to radioiodide destruction, several types of cancer cells have been transfected with the NIS gene. This has demonstrated the feasibility of the in vitro technique but also raised the problem of the absence of the iodide organification machinery in non-thyroidal cells, which, at the moment, represents the major limit of this strategy.     

The rat sodium iodide symporter gene permits more effective radioisotope concentration than the human sodium iodide symporter gene in human and rodent cancer cells

Expression of the sodium iodide symporter (NIS) gene in tumor cells may provide a novel mechanism for treating cancer. The NIS mediates the normal physiological transport of iodide across the thyroid cell membrane. This mechanism of iodide uptake has been used to both diagnose and treat thyroid cancer. Tissue expression of the NIS is largely limited to the thyroid; therefore, expression of the NIS gene in cancer cells would allow for specific iodine uptake, radioisotope accumulation, and treatment. In this study, we directly compared the human and rat NIS (rNIS) for their ability to concentrate radioisotope into human and rodent cancer cells. Perchlorate-sensitive (125)I uptake in multiple cell lines was demonstrated following transduction with retroviral vectors expressing either the human or rNIS gene. Surprisingly, iodine uptake was consistently higher with the rNIS gene, up to 5-fold greater, when compared to the human gene, even within a variety of human tumor cell lines. This iodine uptake allowed for cell killing following (131)I treatment in NIS-transduced cells when assayed by in vitro clonogenic assays. These results demonstrate that the rNIS gene provides superior iodine uptake ability, and may be preferable for use in designing anticancer gene therapy approaches.     

Effects of a Phosphoinositide-3-Kinase Inhibitor on Anaplastic Thyroid Cancer Stem Cells

Background: Thyroidectomy, radioactive iodine therapy, chemotherapy, or their combination are treatments of choice for thyroid cancers. However, cancer stem cells (CSCs) may become resistant to therapy, and mutations in somatic genes affect radioiodine uptake. This study determined the effect of a phosphoinositide-3-kinase (PI3K) inhibitor on anaplastic thyroid CSCs. Materials and Methods: The magnetic-activated cell sorting assay was used for segregating CD133-positive CSCs from three anaplastic thyroid carcinoma (ATC) cell lines (C643, SW1736, and 8305C). After confirming the cells’ purity by flow cytometry, they were treated with 5, 10, 20, or 25 μM LY294002, a PI3K inhibitor, and then evaluated at 24 and 48 h. The sodium-iodide symporter (NIS) mRNA level was determined using the quantitative real-time polymerase chain reaction. NIS protein expression was evaluated using western blotting. Results: The PI3K inhibitor, at different concentrations and times, increased the NIS mRNA level (1.30-6.17-fold, P < 0.0001). If the NIS mRNA level in LY294002-treated CD133-positive CSCs was increased more than 2-fold, the NIS protein content was detectable. Conclusions: CD133-positive CSCs isolated from ATC cell lines expressed NIS mRNA and protein after PI3K inhibition. Our findings suggest that molecularly targeted CSC therapy may improve the treatment efficacy of aggressive cancers like ATC.