Molecular markers for predicting response to tamoxifen in breast cancer patients

Tamoxifen is one of the most effective treatments for breast cancer. Standard practice is to select patients who are likely to respond to this therapy through the evaluation of estrogen receptor (ER) and progesterone receptor (PR) in the primary tumor tissue. Over the past 25 yr that physicians have been using ER determination to guide tamoxifen use, numerous studies have demonstrated that this molecular marker is useful in predicting benefit from tamoxifen. ER has been analyzed for many years using ligand-binding assays. However, current practice involves the use of immunohistochemical-based assays to detect ERα Immunohistochemistry (IHC) has several advantages. For example, IHC evaluates tumor cell heterogeneity, can be used to study small samples, is less expensive, and allows direct correlation with multiple histopathological tumor features and other molecular markers. PR, an estrogen-responsive protein, can also be useful in predicting response to tamoxifen in specific clinical situations. In recent years, several other markers of tamoxifen response have been examined, including: pS2 (another estrogen-regulated protein), heat-shock proteins 27 and 70, bcl-2 protein, c-erbB-2 (HER-2/neu) oncoprotein, and mutated p53 tumor suppressor protein. In this article, we present an analysis of the data on these new molecular markers. Overall, from numerous studies, the data indicate that in addition to ERα bcl-2 is a potential candidate to help further improve our ability to predict response to tamoxifen. ER and bcl-2 are the most useful molecular markers to better identify breast cancer patients who will respond to tamoxifen and who will have prolonged survival.     

三苯氧胺联合塞来昔布预防大鼠乳腺癌发生的实验研究

背景与目的:三苯氧胺能有效预防乳腺癌的发生,但并非全部有效。多种肿瘤细胞表达环氧化酶-2(cyclooxygenase-2,COX-2),其表达与肿瘤的发生发展有关。本研究观察三苯氧胺联合COX-2选择性抑制剂塞来昔布对化学致癌剂7,12-二甲基苯蒽(7,12-dimethybenzanthracene,DMBA)诱发的大鼠乳腺癌形成的影响。方法:DMBA油剂灌胃制备大鼠乳腺癌模型,每组30只大鼠,分为单纯诱癌组、三苯氧胺组、塞来昔布组和联合药物组4组,观察各组肿瘤发生率、潜伏期、肿瘤数目及体积的差异。结果:(1)乳腺肿瘤发生率三苯氧胺组(48.15%,13/27)、塞来昔布组(50.00%,14/28)低于单纯诱癌组(85.71%,24/28),高于联合药物组(21.43%,6/28);(2)乳腺肿瘤发生时间三苯氧胺组[(97.54±1.85)天]、塞来昔布组[(96.79±2.89)天]晚于单纯诱癌组[(89.50±5.99)天],早于联合药物组[(103.67±3.39)天];(3)乳腺肿瘤数目三苯氧胺组[(1.77±0.73)个]、塞来昔布组[(1.71±0.61)个]小于单纯诱癌组[(3.50±1.62)个],大于联合药物组[(1.17±0.42)个];(4)乳腺肿瘤体积三苯氧胺组[(1.78±0.71)cm3]、塞来昔布组[(2.05±1.04)cm3]小于单纯诱癌组[(6.42±3.96)cm3],大于联合药物组[(0.71±0.96)cm3],且均有统计学意义(均为P<0.05)。结论:塞来昔布和三苯氧胺能抑制DMBA诱发的大鼠乳腺癌的发生、发展,两者联合使用效果更好。     

Changes in DNA Damage Repair Gene Expression and Cell Cycle Gene Expression Do Not Explain Radioresistance in Tamoxifen-Resistant Breast Cancer

Tamoxifen-induced radioresistance, reported in vitro, might pose a problem for patients who receive neoadjuvant tamoxifen treatment and subsequently receive radiotherapy after surgery. Previous studies suggested that DNA damage repair or cell cycle genes are involved, and could therefore be targeted to preclude the occurrence of cross-resistance. We aimed to characterize the observed cross-resistance by investigating gene expression of DNA damage repair genes and cell cycle genes in estrogen receptor-positive MCF-7 breast cancer cells that were cultured to tamoxifen resistance. RNA sequencing was performed, and expression of genes characteristic for several DNA damage repair pathways was investigated, as well as expression of genes involved in different phases of the cell cycle. The association of differentially expressed genes with outcome after radiotherapy was assessed in silico in a large breast cancer cohort. None of the DNA damage repair pathways showed differential gene expression in tamoxifen-resistant cells compared to wild-type cells. Two DNA damage repair genes were more than two times upregulated (NEIL1 and EME2), and three DNA damage repair genes were more than two times downregulated (PCNA, BRIP1, and BARD1). However, these were not associated with outcome after radiotherapy in the TCGA breast cancer cohort. Genes involved in G₁, G₁/S, G₂, and G₂/M phases were lower expressed in tamoxifen-resistant cells compared to wild-type cells. Individual genes that were more than two times upregulated (MAPK13) or downregulated (E2F2, CKS2, GINS2, PCNA, MCM5, and EIF5A2) were not associated with response to radiotherapy in the patient cohort investigated. We assessed the expression of DNA damage repair genes and cell cycle genes in tamoxifen-resistant breast cancer cells. Though several genes in both pathways were differentially expressed, these could not explain the cross-resistance for irradiation in these cells, since no association to response to radiotherapy in the TCGA breast cancer cohort was found.     

ER-α30和ER-α36在乳腺癌组织的表达及意义

目的探讨新型雌激素受体亚型ER-α30和ER-α36在乳腺癌中的表达及与他莫昔芬治疗预后的关系。方法收集2015年1月至2015年11月间在河北北方学院附属第一医院接受他莫昔芬内分泌治疗的Luminal A型乳腺癌患者75例,并收集同时期30例ER(-)乳腺癌患者组织。采用免疫组化染色SP法检测ER-α30和ER-α36蛋白表达。分析ER-α30和ER-α36蛋白表达与Luminal A型乳腺癌临床病理特征的关系。随访患者的无病生存时间(DFS)。采用Cox风险比例回归模型分析影响DFS的因素。结果Luminal A型乳腺癌组织中ER-α30蛋白阳性表达率为32.0%(24/75),低于ER(-)乳腺癌组织(P<0.05)。ER-α30蛋白表达与TNM分期、肿瘤直径、浸润深度、淋巴结转移、孕激素受体状态有关(P<0.05)。ER-α36蛋白阳性表达率为52.0%(39/75),与ER(-)乳腺癌组织比较差异无统计学意义(P>0.05)。ER-α36蛋白表达与TNM分期和肿瘤直径有关(P<0.05)。随访时间为11~54个月,患者48个月无病生存率为64.0%(48/75)。ER-α30阳性患者48个月无病生存率为33.33%(8/24),阴性患者为78.43%(40/51),差异具有统计学意义(P=0.001)。ER-α36阳性患者48个月无病生存率为48.7%(19/39),阴性患者为80.6%(29/36),差异具有统计学意义(P=0.002)。Cox风险比例回归分析显示,ER-α30、ER-α36是影响Luminal A型乳腺癌患者DFS的独立预后因素(P<0.05)。结论Luminal A型乳腺癌ER-α30和ER-α36阳性表达者接受他莫昔芬治疗无病生存期较短,其有望成为预测他莫昔芬治疗反应性的重要指标。     

他莫昔芬体外促进HepG2细胞脂肪变性观察

目的：研究他莫昔芬（TAM）对体外培养的HepG2细胞脂肪变性以及脂类代谢调控关键因子表达的影响。方法应用油酸（50μmol/L）处理HepG2细胞,诱导细胞脂肪变性体外模型,同时给予不同浓度的TAM （5～20μmol/L）干预72 h;采用油红O染色和甘油三酯含量测定检测HepG2细胞内脂质聚集情况;应用蛋白印迹法检测固醇调节元件结合蛋白-1c（SREBP-1c）、脂肪酸合成酶（FAS）、硬脂酰辅酶A去饱和酶（SCD）、肉酯软脂酰基转移酶（CPT1）和微粒体甘油三酯转移蛋白（MTP）的表达;采用细胞活性检测试剂盒测定细胞活性。结果在干预72 h后,模型组细胞内甘油三酯含量为（16.53＆#177;0.17） mg/100 mg蛋白质,在5μmol/L TAM处理细胞内甘油三酯含量为（17.77＆#177;0.05） mg/100mg蛋白质,与模型组无显著性差异,但在10μmol/L和20μmol/L TAM处理组较模型组分别增加了31%[（21.57＆#177;0.16） mg/100 mg蛋白质]和44%[（23.82＆#177;0.44） mg/100 mg蛋白质],（P＆lt;0.05）;TAM上调细胞内SREBP-1c、FAS、SCD和MTP蛋白表达,但并不改变CPT1蛋白表达;TAM在5～20μmol/L范围内不影响HepG2细胞活性。结论 TAM可促进油酸诱导的HepG2细胞脂肪变性,其主要机制可能是通过上调SREBP-1c及其下游基因,如FAS和SCD的表达而增加了脂肪酸的合成。     

Results from a randomized trial of a web-based,tailored decision aid for women at high risk for breast cancer

Objective

To assess the impact of Guide to Decide (GtD), a web-based, personally-tailored decision aid designed to inform women's decisions about prophylactic tamoxifen and raloxifene use.

Methods

Postmenopausal women, age 46–74, with BCRAT 5-year risk ≥1.66% and no prior history of breast cancer were randomized to one of three study arms:intervention (n = 690), Time 1 control (n = 160), or 3-month control (n = 162). Intervention participants viewed GtD prior to completing a post-test and 3 month follow-up assessment. Controls did not. We assessed the impact of GtD on women's decisional conflict levels and treatment decision behavior at post-test and at 3 months, respectively.

Results

Intervention participants had significantly lower decisional conflict levels at post-test (p < 0.001) and significantly higher odds of making a decision about whether or not to take prophylactic tamoxifen or raloxifene at 3-month follow-up (p < 0.001) compared to control participants.

Conclusion

GtD lowered decisional conflict and helped women at high risk of breast cancer decide whether to take prophylactic tamoxifen or raloxifene to reduce their cancer risk.

Practice implications

Web-based, tailored decision aids should be used more routinely to facilitate informed medical decisions, reduce patients’ decisional conflict, and empower patients to choose the treatment strategy that best reflects their own values.     

Tamoxifen对大鼠脊髓损伤后炎症反应的影响

目的：探讨tamoxifen对大鼠脊髓损伤（SCI）后炎症反应的影响。方法：60只SD大鼠采用改良Allen法建立大鼠SCI模型,并随机分为假手术组、对照组和干预组各20只,采用免疫荧光和免疫印迹探讨各组小胶质细胞活化以及炎性因子白介素-1β（IL—1β）的表达情况,采用伊文思蓝定量测定法观察SCI后血脊髓屏障通透性（BSCB）的变化。结果：SCI后小胶质细胞明显活化,并产生大量的炎性因子IL-16,BSCB的通透性也显著升高;干预组大鼠给予tamoxifen干预后,与对照组比较小胶质细胞活化受到抑制,IL-1β的产生有所减少,BSCB的破坏也得到明显改善（均P〈0．05）。结论：Tamoxifen可以减轻大鼠SCI后炎症反应,促进血脊髓屏障的恢复。     

他莫昔芬和莪术油联合治疗大鼠子宫内膜异位症的实验研究

目的观察选择性雌激素受体调节剂他莫昔芬（TAM）与中药促细胞凋亡剂（莪术提取物）联合用药对大鼠子宫内膜异位症的治疗效果。方法建立雌性大鼠子宫内膜异位症模型,随机分为对照组,TAM、阿拉瑞林（GnRHa）和TAM＋莪术油治疗组,治疗4周后观察异位内膜生长情况,切取在位与异位子宫内膜,行HE染色观察组织形态学变化,SP免疫组化法检测异位内膜血管内皮生长因子（VEGF）的表达。结果各治疗组治疗后异位内膜体积较治疗前及对照组减小（P〈0．05）;治疗后各治疗组异位内膜的VEGF表达评分较对照组少,其差异有统计学意义（P〈0．05）;治疗后TAM组与阿拉瑞林（GnRHa）组、TAM组与TAM＋莪术油组异位内膜VEGF表达评分差异有统计学意义（P〈0．05）。结论TAM结合莪术油可使大鼠异位内膜病灶缩小,病灶VEGF表达降低。     

应用他莫昔芬治疗Ⅲ型前列腺炎合并少精症的初步研究

目的 初步研究枸橼酸他莫昔芬治疗Ⅲ型前列腺炎合并少精症的效果.方法 28例诊断为Ⅲ型前列腺炎合并少精症患者,给予枸橼酸他莫昔芬10 mg,每日2次,连续12周,对比分析患者治疗前后的症状、EPS常规、NIH-CPSI评分、精液常规分析、国际勃起功能评分(IIEF-5评分).结果 治疗前后患者前列腺炎常规检查总WBC计数,精液常规中精子量、精子计数比较,差别有统计学意义(P＜0.05);治疗前后患者排尿症状评分、生活质量评分、疼痛评分及NIH-CSPI总评分,A+B级精子相比较,差别无统计学意义(P＞0.05).结论 枸橼酸他莫昔芬对Ⅲ型前列腺炎合并少精症有一定的治疗效果,但仍需要进一步的深入研究.     

三苯氧胺逆转过表达BCRP的JAR/VP16细胞对VP16的耐药性

目的 探讨三苯氧胺(TAM)对过表达乳腺癌耐药蛋白(BCRP)的JAR/VP16细胞的逆转耐药作用.方法 在人绒癌细胞株JAR和对VP16耐药的JAR/VP16细胞株中以MTT法比较单药VP16组、TAM组及两药联合组的药物毒性,并运用流式细胞术以hochest 33342和PI双染观察两株细胞在加与不加TAM时的胞内荧光值强度.以RT-PCR和Western blot方法在mRNA水平和蛋白水平观察TAM、VP16及两药联用时BCRP表达水平.结果 JAR/VP16细胞株与JAR细胞相比,BCRP的表达量上调;TAM能显著增加VP16的抗肿瘤作用,与VP16单药组相比,联合用药组的细胞抑制率增加(P＜0.05);TAM可下调BCRP的表达.结论 BCRP的过表达可能导致了JAR/VP16细胞对VP16的耐药,而TAM可通过下调BCRP的表达及抑制BCRP的功能,从而逆转这种耐药.