人甲状腺髓样癌细胞株的研究进展

甲状腺髓样癌是常见的头颈部恶性肿瘤,也是近年来发病率增加最快的恶性肿瘤之一,近年来对其基础研究较为关注。本文复习有关文献,对已建株的人甲状腺髓样癌细胞株(TT细胞株)的特性及研究进展全面总结,以期对临床及药物的研发提供帮助。     

甲状腺髓样癌研究进展

甲状腺髓样癌来源于分泌降钙素的甲状腺滤泡旁细胞（又称C细胞），且多因RET基因突变引发，其发病、诊断和治疗等都独具特点，本文重点综述了近年来甲状腺髓样癌基础研究和临床治疗方面的进展。     

Abnormal expression of the MOS proto-oncogene in human thyroid medullary carcinoma

We have been studying the expression of a range of proto-oncogenes in human thyroid tumour tissue by using Northern blot analysis. We have demonstrated the expression of a MOS mRNA of 1 kb in all thyroid samples. Furthermore, in a medullary carcinoma sample we also observed additional mRNA species of 1.7 and 2.2 kb. Southern blot analysis of DNA prepared from the same tumour sample did not reveal a rearrangement of the gene. These findings are the first report of MOS expression in any human tissue, and indicate that MOS oncogene activation might be important in the development of some thyroid tumours.     

Neck management in medullary thyroid carcinoma

Aims

The aims of this study were to retrospectively evaluate incidence and patterns of lymph node metastases, surgical treatment and prognostic factors of medullary thyroid carcinoma.

Methods

Out of a group of 70 MTC patients data of 67 patients were collected. Sixty-two of these patients underwent surgery. Apart from thyroidectomy, 16 patients underwent a bilateral neck dissection, 21 a unilateral neck dissection and 29 a paratracheal dissection or node-picking operation. Thirty-six patients were irradiated, of which 31 postoperatively and five with palliative intent.

Results

Lymph node metastases were found in 91% of the ipsilateral neck dissection specimens, 91% of the paratracheal dissections and 63% of the contralateral dissections. Of the 12 elective neck dissections, 5 were tumor positive. Level VI was positive in 91% of the cases where a dissection was done, whereas preoperatively only 16% were scored tumor positive. During follow-up 22 of the 67 patients developed one or more locoregional recurrences (in total 28 recurrences). The most important factors that were correlated with a worse prognosis of survival were late stage of disease (stage III and IV) (p = 0.0014), high number of positive lymph nodes (p = 0.0023) and incomplete surgical resection (p = 0.0002).

Conclusions

The high rate of locoregional recurrences in this study are a strong argument for a more aggressive approach to the primary and neck. A routine central and ipsilateral selective neck dissection of levels II–V should be considered in all MTC patients based on the high incidence of metastases and the relative low morbidity of a unilateral neck dissection. Patients referred after thyroidectomy alone with elevated (stimulated) calcitonin levels should be re-operated, performing an elective or therapeutic central and unilateral neck dissection.     

甲状腺髓样癌临床病理分析

目的:探讨甲状腺髓样癌(MTC)的临床病理特点、免疫表型及电镜诊断特点。方法:回顾性分析10例甲状腺髓样癌的临床资料,采用免疫组化、组织化学方法研究其病理形态特点,结合文献分析甲状腺髓样癌的电镜诊断特点。结果:散发型甲状腺髓样癌8例,家族型甲状腺髓样癌2例,6例淋巴结转移;9例肿瘤间质刚果红染色( );免疫组化:癌组织中降钙素( )10例、铬粒素A( )10例、突触素( )7例,1例见甲状腺球蛋白阳性细胞,CD44V6在髓样癌中的阳性表达率为60%;电镜下见癌细胞胞质内有大小不一的神经内分泌颗粒。结论:MTC具有多分化肿瘤的特点,可产生多种神经内分泌物质;其诊断依赖于组织病理学、免疫组化和组织化学,电镜在MTC的诊断中有重要价值;降钙素(CT)是其特异性标记物;CD44V6的高表达与MTC的颈部淋巴结转移密切相关。     

Lethal efficacy of doxorubicin on human medullary thyroid carcinoma cells in vitro

Cytotoxicity of doxorubicin was evaluated on a cultured human thyroid carcinoma (MTC) cell line, TT, by the colony-formation technique. The concentration-dependent survival curve showed a biphasic exponential pattern. Doxorubicin in concentrations of 5 X 10(-9) to 3 X 10 (-5) M produced a 15% to 71% cell kill after 1 hr of treatment. Mean lethal concentrations, 0.6 and 59 micrograms/ml, were considerably higher than those reported for cells of other tumors. Prolonged continuous treatment with a single concentration (1 X 10(-8) M) resulted in a cell kill of only 39% by 20 hr, and no further improvement was achieved with extended treatment of up to 48 hr. That doxorubicin activity was not enhanced by prolonged treatment was shown by controls not to be due to inactivation of the drug. Our results suggest that TT cells are somewhat resistant to doxorubicin and that acute administration of larger doses rather than continuous infusion of small doses should perhaps be considered when doxorubicin is used in patients with metastatic MTC.     

Inhibition effects of parathyroid hormone on human medullary thyroid carcinoma cells

Objective:The purpose of the study was to investigate the ef ects of parathyroid hormone and parathyroid hor-mone receptor monoclonal antibody on in vitro growth and proliferation of human medul ary thyroid carcinoma celllines. Methods:The medul ary thyroid carcinoma cellline was cultured in vitro, with parathyroid hormone and parathyroid hormone receptor monoclonal antibody treatment intervention, the growth of the cells was observed under an inverted contrast micro-scope, the MTT assay was used to detect the cellgrowth inhibition rate. Results:Under the inverted contrast microscope, the cells changed significantly, the parathyroid hormone and parathyroid hormone receptor monoclonal antibodies can ef ectively inhibit the proliferation of medul ary thyroid cancer cells in a time and dose dependent. When parathyroid hormone concentra-tion reached a concentration of 2.0μmol/L, the parathyroid hormone receptor monoclonal antibody reached a concentration of 1.0μmol/L, the cellgrowth was most significantly inhibited (P<0.05). Conclusion:Parathyroid hormone and parathyroid hormone receptor monoclonal antibody were able to inhibit the proliferation of medul ary thyroid carcinoma cells and signifi-cantly reduce the proliferation index.     

Cytophotometric DNA measurements in medullary thyroid carcinoma

The prognostic significance of objectively measured karyometric variables (ploidy pattern, nuclear roundness, area, elongation, chromatin texture, and nearest nucleus distance) was investigated in relation to clinical (stage and type of disease) and morphologic (histologic patterns) variables in 27 patients with the diagnosis of medullary thyroid carcinoma (MTC). The DNA and karyometric measurements of Feulgen-stained nuclei were made with a video cytometry system. The five-year and ten-year adjusted survival rates were 74.4 +/- 10.1% and 59.5 +/- 15.6%, respectively. Cox's survival analysis for mortality showed that only stage, age, sex, and 5N exceeding rate had predictive value (overall P = 0.0012) in decreasing order. Patients with the best prognosis were young females with clinical Stage I disease and low 5N exceeding rate tumors. When karyometric and histometric variables were considered by themselves survival correlates with the standard deviation (SD) of the nearest nuclear distance and nuclear elongation; that is, patients with crowded, high cellularity tumors and elongated cells had the worst prognosis. In univariate analyses only clinical stage correlated with adjusted survival rate. Multivariate survival analysis for morbidity showed that patients in Stages greater than or equal to II and high SD of ploidy values were free of symptoms for short intervals. When morphometric data were considered alone, patients with high variance in the chromatin texture and highly variable nuclear areas had shorter asymptomatic intervals.     

Melanin production in a medullary thyroid carcinoma

Melanin production by a medullary thyroid carcinoma (MTC) is reported and discussed. Immunohistochemically, the tumor cells contained calcitonin; by electron microscopy, they bore numerous, heterogeneous granules similar to those described previously in MTCs. One small focus of tumor was pigmented. Here, melanosomes in different stages of maturation were found in dendritic cells that ramified among granule-bearing cells. The remarkable phenotypic divergence in this solitary, nongerm cell neoplasm is unusual but not so surprising in light of the APUD nature and neural crest origin of both the melanocyte and the thyroid C cell, which gives rise to MTC. The authors view the calcitonin and melanosome phenotypes as closely related tumor clones evolving from a common precursor neoplastic cell. This unique "experiment of nature" adds to the set of rare human tumors that make melanin "ectopically."     

Gastrin-releasing peptide immunoreactivity in medullary thyroid carcinoma

Two cases of gastrin releasing peptide (GRP)-producing medullary thyroid carcinoma are presented. Immunohistochemical examination revealed the presence of GRP-like immunoreactivity (IR-GRP) in the primary tumor tissues. High concentration of IR-GRP was also demonstrated in extracts of the primary tumors by radioimmunologic means with use of a GRP-specific antiserum. Chromatographic analysis showed that the immunoreactivity was composed of at least two molecular forms: one behaved as synthetic porcine GRP on Sephadex G-50 gel filtration and the other as porcine GRP (14-27), a C-terminal active fragment of GRP. The IR-GRP was shown not to be attributed to bombesin-like immunoreactivity. Substance P-like immunoreactivity was not detected in the tumor tissues by either immunohistochemical or radioimmunologic means. This is, as far as the authors are aware, the first finding of IR-GRP as an ectopic product in medullary carcinoma.     

alpha-Neoendorphin-like immunoreactivity in medullary carcinoma of the thyroid

alpha-Neoendorphin-like immunoreactivities (alpha-NE-IR) were demonstrated in tissues from three patients with medullary carcinoma of the thyroid (MCT). A large amount of alpha-NE-IR was detected in the extracts of primary tumors and metastatic lymphatic tissues by a highly sensitive and specific radioimmunoassay (RIA). Gel filtration analyses showed two different molecular-weight forms of the alpha-NE-IR: One eluted at the void fraction and the other at the position of [125I]-alpha-NE on Sephadex (Pharmacia Fine Chemical, Uppsala, Sweden) G-50 chromatography. Immunohistochemical examination revealed the presence of alpha-NE-IR in the C-cell carcinoma. These data presumably reflect that alpha-NE, the opioid peptide derived from preproenkephalin B, is synthesized in the MCT.     

甲状腺髓样癌的预后因素分析

目的　评估影响甲状腺髓样癌预后的因素。方法　采用统计学单、多因素分析研究本院初治 5 3例甲状腺髓样癌的预后因素。结果　总的 5年、10年、15年生存率各自为 6 6 %、5 9.9%和 5 3.2 %。单因素分析示 :原发灶累及双侧 ,原发灶 >4cm ,病灶外侵甲状腺包膜 ,无腹泻症状 ,远处转移 ,手术彻底程度影响预后。多因素示 :手术彻底程度是影响甲状腺髓样癌生存的独立预后因素。结论　手术彻底程度是影响甲状腺髓样癌生存的独立预后因素。     

以RET为靶点治疗甲状腺髓样癌

甲状腺髓样癌(MTC)是甲状腺滤泡旁细胞的恶性肿瘤,分为散发型和遗传型,它是MEN2A、MEN2B和FMTC 3种遗传性综合征共同的临床特征.RET原癌基因编码跨膜的酪氨酸激酶受体,该基因的突变及多态性可以通过不同的信号转导途径激活RET酪氨酸激酶区引起MTC的发生.目前,RET原癌基因已被作为MTC分子治疗的靶点,但尚无针对RET基因相关肿瘤的有效治疗策略.     

Dendritic cell vaccination in medullary thyroid carcinoma.

PURPOSE: Prognosis and treatment effectiveness for medullary thyroid carcinoma (MTC) are strictly related to tumor stage. Palliative treatment options show no significant benefit. A promising treatment approach for human cancer is based on the vaccination of autologous dendritic cells (DCs). EXPERIMENTAL DESIGN: The objective of this study was to evaluate the effectiveness of DC vaccines in MTC patients. Therefore, we generated autologous tumor lysate-pulsed DCs from 10 patients suffering from advanced MTC for repeated vaccination. Mature DCs were derived from peripheral blood monocytes by using CD14 magnetic bead selection and subsequent culture in the presence of granulocyte macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor alpha with or without addition of IFN-gamma. DCs were loaded with tumor lysate and further injected into a groin lymph node. Toxicity, tumor marker profile, immune response, and clinical response were determined. RESULTS: Vaccination was well tolerated and induced a positive immunological response in all of the tested patients as evaluated by in vivo delayed-type hypersensitivity reactivity or in vitro intracytoplasmic IFN-gamma detection assay. Three patients had a partial response, 1 patient presented a minor response, and 2 patients showed stable disease. The remaining 4 patients had progressive disease. CONCLUSIONS: These data provide strong evidence that vaccination with tumor-lysate pulsed DCs results in the induction of a specific immune response in patients suffering from MTC. Objective clinical responses could be observed even for far-advanced disease. Therefore, we suggest that MTC is particularly suited for DC-based immunotherapy.     

甲状腺髓样癌的辅助治疗

目的 评价放射治疗、化学治疗和放射性核素186Re对晚期甲状腺髓样癌的疗效。方法 回顾性分析本院1960年6月～2000年7月间接受放疗、化疗或放射性核素治疗的甲状腺髓样癌患者疗效。结果 放射治疗对术后肉眼残留者3年局控率为33．3％(3／9例)，对镜下残留者3年局控率达63．6％(7／11例)，单用放射治疗无效(3例)。化学治疗疗效不明显(11例)。放射性核素186Re对晚期甲状腺髓样癌肿瘤灶有抑制生长作用。结论 放射治疗对术后镜下残留、肉眼残留者不失为手术治疗的有益补充，能明显提高局控率。放射性核素186Re的治疗价值有待研究。     

Low telomerase activity: possible role in the progression of human medullary thyroid carcinoma

Maintenance of telomere length has been reported to be an absolute requirement for unlimited growth of human tumour cells and in about 85% of cases, this is achieved by reactivation of telomerase, the enzyme that elongates telomeres. Only in rare cases, like in human medullary thyroid carcinomas (MTC), telomerase activity (TA) is low or undetectable; however, this does not limit tumours to become clinically significant. Here, we report that very low TA (below 5% of HEK293) observed in MTC cell strains derived from different patients, although not sufficient for immortalising the cells, is necessary for prolonging their replicative life span. Telomere erosion led to induction of a crisis period after long-term in vitro cultivation, which was reached earlier when treating the cells with MST-312, a telomerase inhibitor at non-toxic concentrations. Crisis was bypassed either by ectopic hTERT introduction or by infrequent spontaneous immortalisation, the latter of which was always associated with telomerase reactivation and changes of the cellular phenotype. While confirming the high importance of telomerase for tumour development, these data draw attention to the relevance of low TA: although insufficient for telomere stabilisation, it allows MTC cells to reach more population doublings, increasing both cell numbers as well as the risk of accumulating mutations and thus might support the development of clinically significant MTC.     

Expression of p8 protein in medullary thyroid carcinoma

BACKGROUND: The p8 protein is involved in various cells under cellular stress, such as apoptotic stimuli. In this study, p8 protein expression was investigated in human medullary thyroid carcinoma. in order to elucidate its physiological significance. MATERIALS AND METHODS: We immunohistochemically investigated p8 expression in 69 cases of medullary thyroid carcinoma. RESULTS: Thirty cases (43.4%) were regarded as a high group of p8 expression with a labelling index of 50% or higher. The p8 expression level was directly linked to lymph node metastasis, extrathyroid extension and UICC stage. Furthermore, there were no cases showing low p8 expression, but 24.8% of those with high p8 expression showed recurrence. However, p8 expression was not linked to the apoptotic index. CONCLUSION: These findings suggest that p8 expression plays an important role in the progression of medullary carcinoma, but does not have an anti-apoptotic function.