曲妥珠单抗对HER-2过表达乳腺癌细胞株mTOR信号通路影响的观察

目的:探讨曲妥珠单抗对HER-2过表达乳腺癌细胞株mTOR信号通路的影响。方法:在培养的乳腺癌细胞株MDA-MB-453中加入曲妥珠单抗,采用蛋白质印迹法检测细胞中mTOR、S6、4EBP1和Akt的蛋白磷酸化水平,同时检测该药对MDA-MB-453增殖及克隆形成的影响。结果:乳腺癌细胞株MDA-MB-453在加入曲妥珠单抗作用下,mTOR、S6、4EBP1和Akt磷酸化明显受抑制,并具有浓度依赖性;乳腺癌细胞株MDA-MB-453在加入曲妥珠单抗后,细胞相对增殖率随着药物浓度增大由(77±6.3)%降至(21±1.5)%,克隆形成率随着药物浓度增大由(55±4)%降至(4±1)%。结论:曲妥珠单抗可通过抑制mTORC1和mTORC2信号通路,从而抑制乳腺癌细胞株MDA-MB-453的生长与增殖。     

血清miR-129-5p水平与HER-2阳性晚期乳腺癌患者曲妥珠单抗敏感性的相关性分析

目的:探索HER-2阳性晚期乳腺癌患者的血清miR-129-5p水平对曲妥珠单抗敏感性的预测价值。方法:入组HER-2阳性晚期乳腺癌患者107例,均接受曲妥珠单抗靶向治疗,依据实体瘤疗效评价标准（RECIST 1.0）将患者分为曲妥珠单抗敏感组（76例）和曲妥珠单抗耐药组（31例）,实时荧光定量PCR法检测初次曲妥珠单抗治疗前患者血清miR-129-5p水平,并与同期35名健康体检女性人群的血清miR-129-5p水平比较;分析患者的血清miR-129-5p水平与其临床病理特征的关系;使用受试者工作特征曲线（receiver operating characteristic,ROC）确定患者血清miR-129-5p水平对曲妥珠单抗治疗敏感性的预测价值和其阈值。结果:曲妥珠单抗敏感组患者的血清miR-129-5p水平显著低于健康对照组（0.627±0.058 vs 1.027±0.129,P=0.001）,而曲妥珠单抗耐药组患者的血清miR-129-5p水平显著低于敏感组患者（0.276±0.031 vs 0.627±0.058,P=0.002）。HER-2阳性晚期乳腺癌患者的血清miR-129-5p水平与年龄、月经情况、ECOG评分、肿瘤转移部位均无关,但与组织学分级及肿瘤转移部位数量有关,I-II级患者的miR-129-5p水平显著低于III级患者,有一个或两个肿瘤转移部位的患者的血清miR-129-5p水平显著低于有三个或以上肿瘤转移部位的患者,差异有统计学意义（P＜0.05）。ROC曲线分析表明患者的血清miR-129-5p水平对区分曲妥珠单抗敏感与耐药患者的阈值为0.43,灵敏度为0.89,特异度为0.72,且曲妥珠单抗耐药组患者血清miR-129-5p≤0.43的患者比例显著高于敏感组患者（71.0% vs 26.3 %,P＜0.05）。结论:HER-2阳性晚期乳腺癌患者的血清miR-129-5p水平可有效预测其对曲妥珠单抗的疗效,有望成为预测患者曲妥珠单抗疗效的有效生物标记物。     

曲妥珠单抗抑制辐射诱导下的乳腺癌细胞系SKBR3细胞的Her-2核转运过程研究

 【摘要】　目的　观察曲妥珠单抗对乳腺癌SKBR3细胞中Her-2的入核过程和核内DNA损伤修复的影响,探讨曲妥珠单抗的放疗增敏机制。方法　克隆形成实验检测曲妥珠单抗对辐射后细胞存活分数（SF）的影响,荧光共聚焦观察曲妥珠单抗对DNA 双链断裂（DSB）损伤标志物γH2AX表达和Her-2核转运过程的影响,免疫印迹法检测曲妥珠单抗对辐射诱导细胞的胞核内Her-2蛋白、DNA依赖蛋白激酶（DNA-PK）功能亚单位DNA-PKcs的表达量的改变。结果　细胞克隆形成实验中,曲妥珠单抗干预组接受2 Gy时SF（SF2）为0.321±0.022,单纯照射组为0.547±0.046（P＝0.000）;辐射后γH2AX的荧光灰度表达提高,曲妥珠单抗干预组为85.40±25.63,单纯照射组为18.53±44.32（P＝0.000）;Her-2蛋白入核灰度表达降低,单纯照射组为52.80±19.74,曲妥珠单抗组为21.41±10.55（P＝0.000）;免疫印迹实验表明曲妥珠单抗干预组辐射后早期核内DNA-PKcs及Her-2的表达下降。结论　曲妥珠单抗能够抑制辐射诱导的Her-2入核过程,并减少核内Her-2和DNA-PKcs的表达,从而可能提高辐射后早期的DSB损伤。     

阿司匹林联合曲妥珠单抗对HER-2阳性乳腺癌细胞增殖和凋亡的影响#br# #br#

目的 探讨阿司匹林联合曲妥珠单抗对表皮生长因子受体2（HER 2）阳性乳腺癌SKBR 3细胞增殖和凋亡的影响。方法 将SKBR 3细胞分为对照组、阿司匹林组（5 mmol／L）、曲妥珠单抗组（30 μg／ml）和联合组（5 mmol／L 阿司匹林+30 μg／ml 曲妥珠单抗）,采用MTT法、流式细胞术分别观察不同药物处理对SKBR-3细胞增殖和凋亡的影响。结果 阿司匹林组SKBR 3细胞增殖率为（79.6±2.61）％,曲妥珠单抗组为（48.2±3.35）％,联合组为（21.5±1.66）％,组间差异有统计学意义（P＜0.05）。阿司匹林、曲妥珠单抗联合作用指数（CI）为1.0,属于叠加作用。阿司匹林组SKBR 3细胞凋亡率为（273±347）％,曲妥珠单抗组为（35.3±2.80）％,联合组为（56.2±3.95）％,组间差异有统计学意义（P＜0.05）。结论 阿司匹林联合曲妥珠单抗能有效抑制HER-2阳性乳腺癌细胞的增殖,两药联合有可能成为HER 2阳性乳腺癌的临床治疗新模式。     

芹菜素与曲妥珠单抗联用对HER2阳性乳腺癌协同抗肿瘤作用

目的 探讨芹菜素与曲妥珠单抗联合应用对人表皮生长因子受体2(HER2)阳性乳腺癌细胞系BT474及SK-BR-3的抗肿瘤作用及其机制。方法 采用流式细胞术检测曲妥珠单抗与人乳腺癌细胞的结合活性;细胞计数试剂盒(CCK-8)检测芹菜素、曲妥珠单抗单药及联合应用对BT474和SK-BR-3细胞的生长抑制活性;EdU染色法检测芹菜素、曲妥珠单抗单药及联合应用对BT474和SK-BR-3细胞DNA复制的影响;蛋白质印迹法检测芹菜素、曲妥珠单抗单药及联合应用对BT474和SK-BR-3细胞中表皮生长因子受体(EGFR)、HER2、HER3、Akt等蛋白及其各自磷酸化蛋白表达水平的影响。设置芹菜素组、曲妥珠单抗组、芹菜素+曲妥珠单抗联合用药组、对照组和空白对照组。结果 生长抑制实验结果显示,芹菜素抑制BT474和SK-BR-3细胞生长的半数抑制浓度值分别为25.70和29.34μmol/L。EdU染色实验结果表明,不同浓度芹菜素(16、32、64μmol/L)单药作用于SK-BR-3和BT474细胞后,与对照组比较差异均有统计学意义,F值分别为99.25和309.10,均P<0.001。芹菜...     

曲妥珠单抗对HER-2高表达胃癌细胞珠抑制作用观察

目的:观察曲妥珠单抗对HER-2高表达人胃癌NCI-N87细胞株的抑制作用.方法:免疫组化法检测HER-2蛋白在NCI-N87细胞中的表达.荧光免疫杂交法(FISH)检测HER-2基因在NCI-N87细胞中的扩增情况.根据是否应用曲妥珠单抗分为对照组与药物组,其中药物组浓度分别为0.1、1、10和100 μg/mL,作用72 h后以CCK8法测定曲妥珠单抗对NCI-N87细胞的生长抑制作用.结果:免疫组化法检测显示,HER-2蛋白在NCI-N87细胞中的表达以细胞膜分布为主,呈棕褐色颗粒状,HER-2蛋白为可疑阳性表达(++).荧光免疫杂交法检测显示,NCI-N87细胞HER-2/CEP17＞2,存在HER-2基因扩增.CCK8实验显示,曲妥珠单抗浓度为0.1、1、10和100 μg/mL时细胞存活率分别为(84.17±1.70)％、(81.21±3.94)％、(83.65±2.48)％和(80.59±4.25)％,四组间比较差异无统计学意义,P＞0.05;与对照组(100％)相比,差异有统计学意义,P=0.000.结论:曲妥珠单抗对HER-2高表达人胃癌NCI-N87细胞具有一定的生长抑制作用;曲妥珠单抗浓度在0.1～100 μg/mL对NCI-N87细胞的抑制作用相似.     

阿帕替尼联合曲妥珠单抗对胃癌细胞的协同增敏作用

目的观察阿帕替尼联合曲妥珠单抗杀伤胃癌NCI-N87细胞的协同增敏作用并探讨可能作用机制。方法CCK-8法检测空白对照组、曲妥珠单抗组(0.1、1、10μg/ml)、阿帕替尼组(1μmol/L)及曲妥珠单抗(0.1、1、10μg/ml)+阿帕替尼(1μmol/L)组对NCI-N87细胞的增殖抑制作用,流式细胞术检测NCI-N87细胞凋亡,Western blotting检测HER-2、VEGFR2、Bax、Bcl-2蛋白表达。结果CCK-8检测提示曲妥珠单抗、阿帕替尼能够抑制NCI-N87细胞增殖,在一定浓度范围内作用呈浓度依赖性和时间依赖性(P<0.01);q值计算提示曲妥珠单抗与阿帕替尼具有协同抑制NCI-N87细胞增殖的作用。流式细胞术检测显示联合组NCI-N87胃癌细胞凋亡较单药组明显升高(P<0.05),其中空白对照组、阿帕替尼组(1μmol/L)、曲妥珠单抗(0.1μg/ml)组及曲妥珠单抗(0.1μg/ml)+阿帕替尼(1μmol/L)组的凋亡率分别为(3.0±1.28)%、(5.8±1.63)%、(8.0±3.92)%和(21.6±6.85)%。曲妥珠单抗+阿帕替尼组与空白对照组、曲妥珠单抗及阿帕替尼单药组比较,HER-2蛋白表达显著下调(P<0.05);曲妥珠单抗+阿帕替尼组与空白对照组比较,Bcl-2蛋白表达、Bcl-2/Bax比值明显降低(P<0.01)。结论阿帕替尼联合曲妥珠单抗可能通过下调HER-2蛋白及调控凋亡相关蛋白Bcl-2、Bax的表达,协同抑制NCI-N87细胞增殖和促进细胞凋亡。     

靶向HER-2受体二聚化的新药——帕妥珠单抗研究进展

帕妥珠单抗（pertuzumab）系新一代人源化单克隆抗体类药物,通过与HER-2胞外受体结构域Ⅱ区的结合,特异性地抑制HER-2受体二聚化。实验研究表明,帕妥珠单抗联合曲妥珠单抗能够更全面地阻断HER-2的信号转导。2012年6月FDA批准帕妥珠单抗用于联合曲妥珠单抗和多西他赛治疗HER-2阳性的转移性乳腺癌,2013年9月30日FDA进一步加速批准该方案作为新辅助治疗用于高风险HER-2阳性的早期乳腺癌。本文全面回顾了帕妥珠单抗的研究进展,并重点介绍该药的临床试验情况,以期为帕妥珠单抗的临床实践应用提供相关的参考依据。     

曲妥珠单抗联合新辅助化疗对HER-2阳性乳腺癌患者近远期疗效的影响

目的 探讨曲妥珠单抗联合新辅助化疗对表皮生长因子受体-2(HER-2)阳性乳腺癌患者的疗效.方法 选取HER-2阳性乳腺癌患者58例,随机分为观察组和对照组,各29例.对照组给予表柔比星联合多西他赛的方案进行新辅助化疗,观察组在对照组的基础上给予曲妥珠单抗治疗.比较两组患者的近期、远期疗效.结果 观察组有效率(RR)及病理完全缓解(pCR)率明显优于对照组,5年总生存率(OS)及5年无病生存率(DFS)明显高于对照组.结论 曲妥珠单抗联合新辅助化疗治疗HER-2阳性乳腺癌近期疗效显著,并可有效改善患者预后,值得临床推广应用.     

曲妥珠单抗治疗失败的HER-2阳性乳腺癌患者不同后续治疗方案的疗效及影响因素分析

目的:观察人表皮生长因子受体2（human epidermal growth factor receptor-2,HER-2）阳性乳腺癌患者曲妥珠单抗治疗失败后不同后续治疗方案的疗效,分析影响因素。方法:回顾性分析2014年1月至2016年12月在我院肿瘤科治疗的曲妥珠单抗治疗失败的94例HER-2阳性晚期乳腺癌患者,根据其后续治疗方案不同将其分为A组（接受单纯化疗）、B组（接受曲妥珠单抗+化疗）和C组（接受拉帕替尼+化疗）;比较三组患者治疗效果,并分析可能影响抗HER-2治疗效果的相关因素。结果:94例患者均完成随访,中位随访时间22.3个月。三组患者中位无进展生存期（median progression free survival,mPFS）分别为3个月、4.5个月及6个月,差异有统计学意义（P<0.000 1）;C组PFS较A组及B组均明显延长,B组PFS较A组明显延长。A、B、C三组客观有效率（objective response rate,ORR）分别为8.7%、29.7%、38.2%,三组的临床获益率（clinical benefit rate,CBR）分别为21.7%、54.1%、64.7%,以上差异均有统计学意义（P<0.05）。对可能影响PFS的单因素进行分析,拉帕替尼、一线疗程（曲妥珠单抗）获益时间≥6个月、无内脏转移是PFS的影响因素;而拉帕替尼、一线疗程（曲妥珠单抗）获益时间≥6个月是PFS的独立影响因素。结论:对于曲妥珠单抗治疗失败的HER-2阳性晚期乳腺癌患者,后续治疗方案中含抗HER-2靶向药物可改善患者预后。     

Selective inhibition of ADAM metalloproteases blocks HER-2 extracellular domain (ECD) cleavage and potentiates the anti-tumor effects of trastuzumab

The HER-2 receptor tyrosine kinase is an important regulator of cell proliferation and survival, and it is a clinically validated target of therapeutic intervention for HER-2 positive breast cancer patients. Its extracellular domain (ECD) is frequently cleaved by protease(s) in HER-2 overexpressing breast cancer patients, rendering the remaining membrane-bound portion (p95) a constitutively activated kinase. The presence of both serum ECD and cellular p95 protein has been linked to poor clinical outcome as well as reduced effectiveness of some therapeutic treatments. We have identified a series of potent, selective small molecule inhibitors of ADAM proteases, exemplified here by INCB003619, and demonstrate that these inhibitors effectively block HER-2 cleavage in HER-2 overexpressing human breast cancer cell lines. Intriguingly, when used in combination, INCB003619 dramatically enhances the antiproliferative activity of suboptimal doses of the anti-HER-2 antibody, trastuzumab, in HER-2 overexpressing/shedding breast cancer cell lines, accompanied by reduced ERK and AKT phosphorylation. Furthermore, INCB003619, in combination with trastuzumab, augments the pro-apoptotic and antiproliferative effects of the chemotherapeutic agent paclitaxel. Consistent with these in vitro data, INCB003619 reduces serum ECD levels and enhances the antitumor effect of trastuzumab in a xenograft tumor model derived from the HER-2 overexpressing BT-474 breast cancer cell line. Collectively, these findings suggest that blocking HER-2 cleavage with selective ADAM inhibitors may represent a novel therapeutic approach for treating HER-2 overexpressing breast cancer patients.     

曲妥珠单抗联合氟尿嘧啶或顺铂治疗胃癌的实验研究

目的：探讨曲妥珠单抗（Herceptin,HCP）联合氟尿嘧啶（5-FU）或顺铂（PDD）治疗胃癌的效果及机制。方法：采用流式细胞检查确定胃癌细胞株的HER-2/neu（HER2）表达情况,并测定药物对细胞周期的影响;以MTT法评价药物的细胞毒性作用;以Westernblot法分析药物对HER2-PI3K-AKT信号转导的影响;以RT-PCR分析药物对靶蛋白酶mRNA的影响。结果：HCP单抗可增强化疗药对HER2阳性细胞的毒性作用。先予5-FU后予HCP单抗、先HCP单抗和PDD联合再序贯使用HCP单抗的方案效果最佳,但先予HCP单抗再和5-FU联合可拮抗5-FU的化疗效果。HCP单抗单用或与化疗药联用均可抑制AKT的磷酸化,HCP单抗与PDD同时使用可抑制NF-κB的核移位;HCP单抗不能增强5-FU对胸苷酸合成酶（TS）mRNA表达的抑制,但可使PDD上调的核苷酸切除修复交叉互补基因（ERCC1）mRNA恢复至正常水平;联合方案对细胞周期的改变影响明显。结论：HCP单抗更适于与PDD联合用于HER2阳性胃癌的治疗,HCP单抗与PDD同时使用再序贯使用HCP单抗的给药方法可能是最佳联合模式;而HCP单抗与5-FU联合则要注意正确的用药次序,以免减弱5-FU的化疗效果。     

Trastuzumab plus paclitaxel or docetaxel in HER-2-negative/HER-2 ECD-positive anthracycline- and taxane-refractory advanced breast cancer

Trastuzumab is considered effective against human epidermal growth factor receptor (HER)-2-positive breast cancer as assessed by immunohistochemistry (IHC) and fluorescence or chromogenic in situ hybridization (FISH/CISH) on biopsy material. Trastuzumab is now approved in both the adjuvant and metastatic settings for this patient population. Because HER-2 extracellular domain (ECD) levels have been correlated with disease progression in the metastatic setting, we considered trastuzumab salvage therapy plus a taxane in heavily pretreated trastuzumab-naive relapsed breast cancer patients with high serum levels of HER-2 ECD (> or =15 ng/ml). All patients had previously failed at least two lines of anthracycline- and taxane-based regimens and were HER-2 negative by IHC and FISH/CISH prior to a centralized reanalysis, and were serum positive for HER-2 ECD (> or =15 ng/ml) at baseline. Regular serum accounts of HER-2 ECD were recorded and compared with response and survival outcomes. Twenty-two patients were finally eligible for salvage therapy. Minor responses were observed in five (23%) and stable disease (SD) was observed in 11 patients, leading to a clinical benefit rate of 73% (16 of 22 patients). The median time to progression and overall survival time were 5 (6.5 months in minor responders and SD) and 12 months, respectively; 11 and eight patients remained progression free for >6 and >12 months, respectively. Eleven and seven patients were alive at 12 and 15 months, respectively, after treatment start. Furthermore, in total, 13 (59.1%) patients obtained a biochemical response. In our study, patients with conventionally HER-2-negative disease but with expression of HER-2 ECD above the normal limit (> or =15 ng/ml) displayed a rapid response, both biochemically and clinically, to the trastuzumab-taxane combination. This is the first study assessing anti-HER-2-based treatment in HER-2-negative advanced breast cancer according to HER-2 ECD positivity; if our results are confirmed, additional patients with "hidden" HER-2-positive breast cancer might benefit from anti-HER-2 treatment.     

Prognostic and Predictive Impact of the HER-2/neu Extracellular Domain (ECD) in the Serum of Patients Treated with Chemotherapy for Metastatic Breast Cancer

BACKGROUND: The extracellular domain of the HER-2/neu -receptor (ECD) is shed from the receptor protein and can be detected in serum. However, the clinical implication of HER-2/neu ECD measurement must be further evaluated. METHODS: In patients with metastatic breast cancer participating in a trial on first-line chemotherapy, the association of serum HER-2/neu ECD with progression-free interval, survival, and response was studied. Blood samples of patients receiving epirubicin and either cyclophosphamide (EC) or paclitaxel (ET) were collected before (n = 103) and in addition, after three courses of therapy (n = 46). RESULTS: HER-2/neu ECD levels correlate with HER-2/neu overexpression of corresponding primary tumors determined by immunohistochemistry (antibody CB11, p = 0.018) with an optimized cut-off at 15 ng/mL. Elevated serum levels of HER-2/neu ECD before chemotherapy were correlated with shorter overall survival (p = 0.0097), but not with reduced progression-free survival and response to chemotherapy. In subgroup analyses, patients with elevated pretherapeutic HER-2/neu ECD levels treated with EC showed shorter overall survival (p = 0.0092); no difference was seen in the ET group. With regard to progression-free survival, patients with elevated HER-2/neu ECD levels tended to benefit from ET (p = 0.0341), in patients with low levels no difference was observed between EC and ET. A decrease of HER-2/neu ECD levels after three courses of therapy was associated with response to therapy (p = 0.006). CONCLUSION: In our group of metastatic breast cancer patients, elevated HER-2/neu ECD levels are associated with decreased overall survival. With regard to progression-free survival, particularly patients with high HER-2/neu ECD levels seem to benefit from taxane-containing chemotherapy.     

Trastuzumab induces antibody-dependent cell-mediated cytotoxicity (ADCC) in HER-2-non-amplified breast cancer cell lines

BackgroundAntibody-dependent cell-mediated cytotoxicity (ADCC) mediated by CD56 + natural killer (NK) cells may contribute to the activity of trastuzumab in HER-2-amplified tumours. In this study, we investigated the possibility that trastuzumab might induce ADCC against HER-2-non-amplified breast cancer cells.MethodsInduction of NK cell-mediated ADCC was examined in trastuzumab-treated HER-2-non-amplified breast cancer cell lines. HER-2 protein levels were also determined in tumour and autologous normal tissue samples from patients with HER-2 negative breast cancer.ResultsTrastuzumab induced a significant ADCC response in the HER-2-amplified HCC1954 and SKBR3 cell lines, and in all five of the non-amplified cell lines, which had low levels of detectable HER-2 by western blot (CAL-51, CAMA-1, MCF-7, T47D, and EFM19). Trastuzumab did not induce ADCC in the K562 control cell line or MDA-MB-468, which has very low levels of HER-2 detectable by enzyme-linked immunosorbent assay (ELISA) only. HER-2 protein was detected by ELISA in 14/15 patient tumour samples classified as HER-2-non-amplified. Significantly lower levels of HER-2 were detected in normal autologous tissue compared with tumour samples from the same patients.ConclusionOur results suggest that HER-2-non-amplified breast cancer cells, with low but detectable levels of HER-2 protein, can bind trastuzumab and initiate ADCC.     

Serum EGF-receptor and HER-2 extracellular domains and prognosis of non-small-cell lung cancer

This retrospective study aimed at evaluating the prognostic impact of high serum levels of either the HER-2 extracellular domain (ECD) or the epidermal growth factor receptor (EGFR) ECD measured using two specific ELISAs in 221 patients with non-small-cell lung cancer (NSCLC) receiving conventional therapy and 41 nonmalignant pulmonary diseases patients. It was not possible to discriminate between lung cancer and benign lung disease owing to the lack of sensitivity-specificity relationship of HER-2 and EGFR ECD levels. Neither HER-2 nor EGFR ECD specific levels were associated with a particular prognosis of NSCLC patients receiving conventional therapy.     

P27(kip1) down-regulation is associated with trastuzumab resistance in breast cancer cells

Trastuzumab (Herceptin) is a recombinant humanized monoclonal antibody directed against HER-2. The objective response rate to trastuzumab monotherapy is 12-34% for a median duration of 9 months, by which point most patients become resistant to treatment. We created two trastuzumab-resistant (TR) pools from the SKBR3 HER-2-overexpressing breast cancer cell line to study the mechanisms by which breast cancer cells escape trastuzumab-mediated growth inhibition. Both pools maintained her-2 gene amplification and protein overexpression. Resistant cells demonstrated a higher S-phase fraction by flow cytometry and a faster doubling time of 24-36 h compared with 72 h for parental cells. The cyclin-dependent kinase inhibitor p27(kip1) was decreased in TR cells, and cyclin-dependent kinase 2 activity was increased. Importantly, exogenous addition of p27(kip1) increased trastuzumab sensitivity. Additionally, resistant cells displayed heightened sensitivity to the proteasome inhibitor MG132, which induced p27(kip1) expression. Thus, we propose that trastuzumab resistance may be associated with decreased p27(kip1) levels and may be susceptible to treatments that induce p27(kip1) expression.     

Resistance to human epidermal growth factor receptor type 2-targeted therapies

The overexpression of the human epidermal growth factor receptor type 2 (HER-2) is an independent prognostic factor of poor outcome in patients with breast cancer. Two compounds have been registered for HER-2-positive tumour treatment: trastuzumab, a humanised antibody directed against the HER-2 extracellular domain, and lapatinib, a small molecule acting as a dual EGF-R and HER-2 tyrosine kinase inhibitor. Although both drugs improve progression-free survival, many patients’ tumours will exhibit primary resistance, or develop secondary resistance, to anti-HER-2 therapies. The recent significant improvement of survival gained with pertuzumab (an antibody disrupting dimerisation of the receptor) or trastuzumab emtansine (T-DM1, a cytotoxic drug vectored by trastuzumab binding) opened the way for new registrations.This review describes the molecular mechanisms by which tumour cells may adapt to and evade HER-2 inhibition by HER-2-targeted therapies and discusses strategies to prevent and overcome resistance to trastuzumab and lapatinib. These strategies may include the establishment of predictive markers, exploration of combination therapies and modulation of nodal targets.     

Inhibition of IGF1R activity enhances response to trastuzumab in HER-2-positive breast cancer cells

Background: Although trastuzumab has improved the prognosis for HER-2-positive breast cancer patients, not all HER-2-positive breast tumours respond to trastuzumab treatment and those that initially respond frequently develop resistance. Insulin-like growth factor-1 receptor (IGF1R) signalling has been previously implicated in trastuzumab resistance. We tested IGF1R inhibition to determine if dual targeting of HER-2 and IGF1R improves response in cell line models of acquired trastuzumab resistance.Materials and methods: HER-2, IGF1R, phospho-HER-2, and phospho-IGF1R levels were measured by enzyme-linked immunosorbent assays in parental and trastuzumab-resistant SKBR3 and BT474 cells. IGF1R signalling was targeted in these cells using both small interfering RNA (siRNA) and the tyrosine kinase inhibitor, NVP-AEW541.Results: IGF1R levels were significantly increased in the trastuzumab-resistant model, SKBR3/Tr, compared with the parental SKBR3 cell line. In both the SKBR3/Tr and BT474/Tr cell lines, inhibition of IGF1R expression with siRNA or inhibition of tyrosine kinase activity by NVP-AEW541 significantly increased response to trastuzumab. The dual targeting approach also improved response in the parental SKBR3 cells but not in the BT474 parental cells.Conclusions: Our results confirm that IGF1R inhibition improves response to trastuzumab in HER-2-positive breast cancer cells and suggest that dual targeting of IGF1R and HER-2 may improve response in HER-2-positive tumours.     

Trastuzumab, paclitaxel, cisplatin, and radiation for adenocarcinoma of the esophagus: a phase I study

Purpose: To conduct a phase I study incorporating trastuzumab with paclitaxel, cisplatin, and radiation for adenocarcinoma of the esophagus. Methods and Materials: Patients with adenocarcinoma of the esophagus without distant organ metastases were eligible. All patients received cisplatin 25 mg/m² and paclitaxel 50 mg/m² weekly for 6 weeks with radiation 50.4 Gy. HER-2/neu-positive patients (2 + /3 + by immunohistochemistry) received weekly trastuzumab at dose levels of 1, 1.5, or 2 mg/kg weekly for 5 weeks after an initial bolus of 2, 3, or 4 mg/kg, respectively. HER-2/neu-negative patients received the same chemoradiation without trastuzumab as a control for toxicity. Dose-limiting toxicities were defined as grade 3 esophageal, cardiac, or pulmonary toxicity. Results: Twelve of 36 screened patients (33%) overexpressed HER-2/neu by immunohistochemistry (seven 3 + and five 2 + ). Eight of 12 patients with HER-2/neu overexpression by IHC had an increase in the number of HER-2/neu genes, six from amplification of the HER-2/neu gene and two were hypderdiploid for chromosome 17. Thirty patients were enrolled (12 HER-2/neu-positive and 18 HER-2/neu-negative controls). No increase in toxicity was seen with the addition of trastuzumab. One of 12 patients in the trastuzumab arm and 8 of 17 in the control arm had grade 3 esophagitis (p ≤ .026). Mean left ventricular ejection fraction for the trastuzumab group was 57% before treatment and 56% after treatment. Conclusion: HER-2/neu is overexpressed in approximately one-third of esophageal adenocarcinomas. Trastuzumab can be added at full dose to cisplatin, paclitaxel, and radiation. Future studies of trastuzumab in esophageal adenocarcinoma are indicated.