Pyrotinib is effective in both trastuzumab-sensitive and primary resistant HER2-positive breast tumors

Objective: Primary resistance to trastuzumab frequently occurs in human epidermal growth factor receptor 2(HER2)-positive(+) breast cancer patients and remains a clinical challenge. Pyrotinib is a novel tyrosine kinase inhibitor that has shown efficacy in the treatment of HER2+ breast cancer. However, the efficacy of pyrotinib in HER2+ breast cancer with primary trastuzumab resistance is unknown.Methods: HER2+ breast cancer cells sensitive or primarily resistant to trastuzumab were treated with trastuzumab, pyrotinib, or the combination. Cell proliferation, migration, invasion, and HER2 downstream signal pathways were analyzed. The effects of pyrotinib plus trastuzumab and pertuzumab plus trastuzumab were compared in breast cancer cells in vitro and a xenograft mouse model with primary resistance to trastuzumab.Results: Pyrotinib had a therapeutic effect on trastuzumab-sensitive HER2+ breast cancer cells by inhibiting phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT) and rat sarcoma virus(RAS)/rapidly accelerated fibrosarcoma(RAF)/mitogen-activated protein kinase(MAPK)/extracellular-signal regulated kinase(ERK)pathways. In primary trastuzumab-resistant cells, pyrotinib inhibited cell growth, migration, invasion, and HER2 downstream pathways, whereas trastuzumab had no effects. The combination with trastuzumab did not show increased effects compared with pyrotinib alone. Compared with pertuzumab plus trastuzumab, pyrotinib plus trastuzumab was more effective in inhibiting cell proliferation and HER2 downstream pathways in breast cancer cells and tumor growth in a trastuzumab-resistant HER2+ breast cancer xenograft model.Conclusions: Pyrotinib-containing treatments exhibited anti-cancer effects in HER2+ breast cancer cells sensitive and with primary resistance to trastuzumab. Notably, pyrotinib plus trastuzumab was more effective than trastuzumab plus pertuzumab in inhibiting tumor growth and HER2 downstream pathways in HER2+ breast cancer with primary resistance to trastuzumab. These findings support clinical testing of the therapeutic efficacy of dual anti-HER2 treatment combining an intracellular small molecule with an extracellular antibody.

Mechanisms of resistance to trastuzumab in HER2-positive gastric cancer

Gastric cancer is one of the most prevalent cancers worldwide,and human epidermal growth factor receptor 2(HER2)-positive cases account for approximately 20%of the total cases.Currently,trastuzumab+chemotherapy is the recommended first-line treatment for patients with HER2-positive advanced gastric cancer,and the combination has exhibited definite efficacy in HER2-targeted therapy.However,the emergence of drug resistance during treatment considerably reduces its effectiveness;thus,it is imperative to investigate the potential mechanisms underlying resistance.In the present review article,we comprehensively introduce multiple mechanisms underlying resistance to trastuzumab in HER2-positive gastric cancer cases,aiming to provide insights for rectifying issues associated with resistance to trastuzumab and devising subsequent treatment strategies.

Xianling Lianxia formula improves the efficacy of trastuzumab by enhancing NK cell-mediated ADCC in HER2-positive BC

Trastuzumab has improved survival rates in human epidermal growth factor receptor 2(HER2)-positive breast cancer(BC),but drug resistance leads to treatment failure.Natural killer(NK)cell-mediated antibody-dependent cell cytotoxicity(ADCC)represents an essential antitumor immune mechanism of trastuzumab.Traditional Chinese medicine(TCM)has been used for centuries to treat diseases because of its capacity to improve immune responses.Xianling Lianxia formula(XLLXF),based on the principle of“strengthening body and eliminating toxin”,exhibits a synergistic effect in the trastuzumab treatment of patients with HER2-positive BC.Notably,this synergistic effect of XLLXF was executed by enhancing NK cells and ADCC,as demonstrated through in vitro co-culture of NK cells and BC cells and in vivo intervention experiments.Mechanistically,the augmented impact of XLLXF on NK cells is linked to a decrease in cytokine inducible Src homology 2(SH2)containing protein(CISH)expression,which in turn activates the Janus kinase 1(JAK1)/signal transducer and activator of transcription 5(STAT5)pathway.Collectively,these findings suggested that XLLXF holds promise for enhancing NK cell function and sensitizing patients with HER2-positive BC to trastuzumab.

BIRC3 induces the phosphoinositide 3-kinase-Akt pathway activation to promote trastuzumab resistance in human epidermal growth factor receptor 2-positive gastric cancer

BACKGROUND Trastuzumab-targeted therapy is currently the standard of care for advanced human epidermal growth factor receptor 2(HER2)-positive gastric cancer.However,the emergence of resistance to trastuzumab poses significant challenges.AIM To identify the key genes associated with trastuzumab resistance.These results provide a basis for the development of interventions to address drug resistance and improve patient outcomes.METHODS High-throughput sequencing and bioinformatics were used to identify the differentially expressed pivotal gene BIRC3 and delineate its potential function and pathway regulation.Tumor samples were collected from patients with HER2-positive gastric cancer to evaluate the correlation between BIRC3 expression and trastuzumab resistance.We established gastric cancer cell lines with both highly expressed and suppressed levels of BIRC3,followed by comprehensive in vitro and in vivo experiments to confirm the involvement of BIRC3 in trastuzumab resistance and to elucidate its underlying mechanisms.RESULTS In patients with HER2-positive gastric cancer,there is a significant correlation between elevated BIRC3 expression in tumor tissues and higher T stage,tumor node metastasis stage,as well as poor overall survival and progressionfree survival.BIRC3 is highly expressed in trastuzumab-resistant gastric cancer cell lines,where it inhibits tumor cell apoptosis and enhances trastuzumab resistance by promoting the phosphorylation and activation of the phosphoinositide 3-kinase-Akt(PI3K-AKT)pathway in HER2-positive gastric cancer cells,both in vivo and in vitro.CONCLUSION This study revealed a robust association between high BIRC3 expression and an unfavorable prognosis in patients with HER2-positive gastric cancer.Thus,the high expression of BIRC3 stimulated PI3K-AKT phosphorylation and activation,stimulating the proliferation of HER2-positive tumor cells and suppressing apoptosis,ultimately leading to trastuzumab resistance.

Impact of oxaliplatin and trastuzumab combination therapy on tumor markers and T lymphocyte subsets for advanced gastric cancer

BACKGROUND Advanced gastric cancer(AGC)remains a challenging malignancy with poor prognosis.The combination of oxaliplatin and trastuzumab has shown promising results in AGC treatment.This study aimed to investigate the effects of oxaliplatin and trastuzumab combination therapy on serum tumor markers and T lymphocyte subsets in patients with AGC and to explore their potential as predictive biomarkers for treatment response.AIM To investigate the impact of oxaliplatin and trastuzumab combination therapy on serum markers and T cell subsets in patients with AGC.METHODS This prospective study enrolled 60 patients with AGC.All patients received oxaliplatin(130 mg/m^(2),every 3 weeks)and trastuzumab(8 mg/kg loading dose,followed by 6 mg/kg every 3 weeks)for six cycles.Serum carcinoembryonic antigen(CEA),cancer antigen 19-9(CA19-9),and cancer antigen 72-4(CA72-4)were measured before and after treatment.T-lymphocyte subsets,including CD3+,CD4+,CD8+,and CD4+/CD8+ratios,were also evaluated.The clinical response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1.RESULTS After six cycles of treatment,the CEA,CA19-9,and CA72-4 serum levels significantly decreased compared to baseline levels(P<0.001).The percentages of CD3+and CD4+T lymphocytes increased significantly(P<0.05),whereas the percentage of CD8+T lymphocytes decreased(P<0.05).The CD4+/CD8+ratio also significantly increased after treatment(P<0.05).Patients with a higher decrease in serum tumor markers(≥50%reduction)and a higher increase in CD4+/CD8+ratio(≥1.5-fold)showed better clinical response rates(P<0.05).CONCLUSION Oxaliplatin and trastuzumab combination therapy effectively reduced serum tumor marker levels and modulated T lymphocyte subsets in patients with AGC.Combination therapy not only has a direct antitumor effect,but also enhances the immune response in patients with AGC.Serum tumor markers and T lymphocyte subsets may serve as potential predictive biomarkers for treatment response in patients with AGC receiving combination therapy.

Quercetin inhibits truncated isoform of dopamine-and cAMP-regulated phosphoprotein as adjuvant treatment for trastuzumab therapy resistance in HER2-positive breast cancer

Trastuzumab resistance is one of the causes of poor prognosis in patients with human epidermal growth factor receptor 2(HER2)-positive(HER2+)breast cancer(BC).The truncated isoform of dopamine-and cAMPregulated phosphoprotein(t-DARPP)has been reported to be involved in trastuzumab therapy resistance and promoting tumor progression.To evaluate the t-DARPP expression in BC,paired tumors and surrounding normal tissues were analyzed by real-time polymerase chain reaction and confirmed higher DARPP-32 kDa family mRNA expression in HER2+BC tumor tissues.We established 2 patient-derived xenografts(PDX)mice models to test the efficacy of trastuzumab,named model 1(non-responder)and model 2(responder).t-DARPP and p95-HER2 protein-protein interactions were detected in PDX tumor tissue from non-responders using Förster resonance energy transfer assays.Instead,there is no response from the responder.Furthermore,mechanistic studies using transwell and western blot assays demonstrated that t-DARPP could upregulate epithelial-mesenchymal transition signaling proteins,enhance p95-HER2 expression and promote cell migration.We found that quercetin effectively reduced t-DARPP expression in HER2+BC cells.In t-DARPP ShRNA-suppressed cells,quercetin synergistically enhanced trastuzumab-induced apoptotic cell death and G2/M phase arrest.In conclusion,the combination of quercetin and trastuzumab treatment by targeting t-DARPP in HER2+BC patients has the potential as a biomarker for mitigating drug resistance.

Trastuzumab联合卡铂对过表达Her-2/neu食管癌细胞的抑制作用

目的:探讨trastuzumab联合卡铂(CBP)对过表达Her-2/neu的食管癌细胞增殖的抑制作用.方法:常规培养食管癌细胞株EC109及TE3,采用流式细胞仪筛选出高表达Her-2/neu的食管癌细胞株EC109;将对数期生长的食管癌EC109细胞分为trastuzumab治疗组、CBP治疗组以及trastu-zumab联合CBP治疗组,分别采用不同工作浓度的trastuzum-ab、CBP以及trastuzumab联合CBP对相应实验组的EC109细胞给药,MTT法检测各组药物在不同工作浓度时对食管癌EC109细胞增殖抑制率,AnnexinV/PI双染色法检测肿瘤细胞凋亡率.结果:Trastuzumab单药、CBP单药或Trastuzumab联合CBP均能有效抑制EC109细胞的增殖,其抑制效应呈剂量依赖性(P<0.05),当药物工作浓度≥1PPC(血浆峰浓度,PPC)时,Trastuzumab联合CBP对EC109细胞的增殖抑制效应明显强于Trastuzumab单药组或CBP单药组,差异有统计学意义(P<0.05).Trastuzumab单药或CBP单药均能诱导EC109细胞凋亡,当药物工作浓度≥1PPC时,Trastuzumab联合CBP诱导的EC109细胞平均凋亡率明显高于Trastuzumab单药组或CBP单药组,差异有统计学意义(P<0.05).结论:Trastuzumab与卡铂联合应用具有协同效应,可以有效地抑制过表达Her-2/neu的食管癌EC109细胞增殖,诱导肿瘤细胞凋亡.

乳腺癌新的生物标志物及其治疗靶点——HER2及trastuzumab的研究进展

近年来 ,HER2及其单克隆抗体trastuzumab(商品名Herceptin)是乳腺癌研究的热点之一。被认为是一新的判断乳腺癌预后的独立标志物和治疗靶点。抗HER2的单抗trastuzumab对晚期。

Trastuzumab修饰四代聚酰胺-胺型枝状聚合物纳米粒靶向结肠癌细胞SW480的研究

目的该研究旨在探讨Trastuzumab修饰四代聚酰胺-胺型枝状聚合物纳米粒对结肠癌SW480的靶向效果,为构建新型的靶向结肠癌的纳米递送系统提供实验数据。方法 MTT法确定SW480细胞摄取PAMAM NPs和PAMAM-Trastuzumab NPs适当的浓度;通过激光共聚焦和荧光显微镜定性观察SW480对罗丹明B标记的PAMAM NPs和PAMAM-Trastuzumab NPs的摄取;并采用流式细胞计数仪定量研究SW480细胞对两者的摄取差别;尾静脉注射荷SW480瘤裸鼠研究两者体内分布情况。结果 PAMAM NPs和PAMAM-Trastuzumab NPs的浓度在0.2 mg/mL时细胞存活率较高且对SW480细胞的毒性较小。激光共聚焦断层扫描显示SW480细胞可以较好地摄取PAMAM-Trastuzumab NPs,同时流式细胞仪定量显示PAMAM-TrastuzumabNPs在SW480细胞的分布较PAMAM NPs高40%(P<0.05)。PAMAM NPs和PAMAM-Trastuzumab NPs在移植瘤中的分布明显多于其他脏器,并且随时间的延长PAMAM-Trastuzumab NPs体现了更好的靶向效果。结论体外与体内实验证明Trastuzumab修饰的PAMAM NPs对结肠癌细胞SW480有很好的靶向效果,可为结肠癌的靶向治疗提供较好的药物载体。

Pertuzumab联合trastuzumab和化疗一线治疗转移性HER2^+胃或胃食管交界癌(JACOB)研究解读

[简评]JACOB研究是继ToGA研究之后又一项针对人类表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)阳性的转移性胃癌的重磅研究,旨在评价另一不同机制的HER2抑制剂-帕妥珠单抗,加入标准一线方案曲妥珠单抗加双药化疗,是否能协同增效、进一步延长HER2阳性转移性胃癌患者的生存时间。遗憾的是,尽管双靶向HER2治疗组的总生存时间(overall survival,OS)较对照组延长3.3个月,但差异无统计学意义(P=0.057)。

Trastuzumab对放射诱导下HER-2的入核及DNA损伤的影响

目的:通过观察HER-2单克隆抗体trastuzumab对BT474细胞中HER-2的入核效应和对核内DNA损伤修复的影响,来探讨HER-2直接入核通路上trastuzumab放疗增敏机制。方法:将BT474细胞随机分成单纯照射组和trastuzumab干预组,通过克隆形成实验来观察各剂量下放射后两组BT474细胞的存活分数的差异,共聚焦显微镜下观测trastuzumab对放射后HER-2核转运和DNA DSB标志物γH_2AX表达的影响,免疫印迹实验检测trastuzumab对放射后早期BT474细胞核内HER-2蛋白、DNA-PKcs的表达影响。结果:与单纯照射组相比,trastuzumab干预组可降低放射后各剂量下BT474细胞的存活分数(SF),共聚焦显微镜可观察到trastuzmnab推迟了照射后HER-2蛋白由细胞膜进入核内的过程,并增加放射后12 h时间点的γH_2AX表达,Western blot实验结果显示trastuzumab干预下调了放射后早期核内DNA-PKcs和HER-2的表达。结论:trastuzumab能够通过减少HER-2的入核,并进一步下调DNA-PKcs活性,抑制放射诱导下BT474的早期DSB修复。

Efficacy and safety of trastuzumab combined with chemotherapy for first-line treatment and beyond progression of HER2-overexpressing advanced breast cancer

Objective： To observe the efficacy and safety of trastuzumab combined with chemotherapy in patients with human epidermal growth factor receptor 2 （HER2）-overexpressing advanced breast cancer. Methods： A total of 90 patients with HER2-overexpressing advanced breast cancer were enrolled in this study. All patients were diagnosed with ductal invasive breast cancer by pathological analysis, and were aged between 31-73 years with a median of 51 years. HER2-positivity was defined as 3（＋） staining in immunochemistry or amplification of fluorescence in situ hybridization （FISH, ratio ≥2.0）. Trastuzumab was administered in combination with chemotherapy as first-line treatment and beyond progression as a second- line, third-line, and above treatment in 90, 34, 14, and 6 patients, respectively. The chemotherapy regimen was given according to normal clinical practice. The response rate was evaluated every two cycles, and the primary endpoints were progression-free survival （PFS） and overall survival （OS）. Survival curves were estimated by using Kaplan-Meier graphs and were compared by using log-rank test statistics. Multivariate analysis was done using Cox＇s proportional hazards regression model, and the level of significance was P〈0.05. Results： All 90 patients received at least one dose of trastuzumab, and efficacy could be evaluated in 85 patients. The median follow-up was 50 months. In total, 72 （80.00%） patients had visceral metastasis, and 43 （47.78%） patients had progressed after one or more extensive chemotherapy regimens for metastatic diseases. The median PFS for first-line trastuzumab was 10 months （range, 2-59 months）, and the median OS after metastasis or initially local advanced disease was 22 months （range, 2-1 16 months）. Conclusions： Trastuzumab combined with chemotherapy was active and well-tolerated as a first-line treatment and even beyond progression in HER2-overexpressing advanced breast cancer as a second-line or third-line treatment. However, its efficacy is certainly less beyond this point.

Trastuzumab plus adjuvant chemotherapy for human epidermal growth factor receptor 2(HER2)-positive early-stage breast cancer: A real-world retrospective study in Chinese patients

Objective: To assess the long-term effectiveness and safety of trastuzumab in adjuvant therapy for Chinese patients with early-stage human epidermal growth factor 2(HER2)-positive breast cancer in a real-world setting.Methods: This retrospective observational study analyzed the medical records of HER2-positive breast cancer patients between 2000 and 2012 at the Chinese Academy of Medical Sciences. Patients who received adjuvant chemotherapy alone or adjuvant chemotherapy followed by/combined with trastuzumab were included. The Kaplan-Meier method was used to estimate disease-free survival(DFS) and overall survival(OS). Hazard ratios(HR) and 95% confidence intervals(95% CI) were calculated using the Cox regression model.Results: Of the 1,348 patients analyzed, 909 received chemotherapy alone and 439 received chemotherapy plus trastuzumab. The 3-year, 5-year and 10-year DFS rates were 83.70%, 76.38% and 68.94%, respectively, in the chemotherapy-alone cohort, and 90.21%, 86.19% and 83.45% in the chemotherapy plus trastuzumab cohort. The3-year, 5-year and 10-year OS rates were 96.10%, 91.40% and 81.88% in the chemotherapy-alone cohort, and98.17%, 94.91% and 90.01% in the chemotherapy plus trastuzumab cohort. The chemotherapy plus trastuzumab group had a significantly lower risk of disease recurrence and death than the chemotherapy-alone group(DFS:HR=0.50, 95% CI, 0.37-0.68;P<0.001;OS: HR=0.53, 95% CI, 0.34-0.81;P=0.004) after adjusting for covariates.In the 439 patients treated with trastuzumab, multivariate analysis suggested that lymph node positivity, higher T stages, and hormone receptor-negative status were significantly associated with higher risks of disease recurrence,and lymph node positivity and hormone receptor-negative status were significantly associated with higher risks of death. Grade 3/4 adverse events(incidence ≥1%) were more common in patients receiving trastuzumab(54.44% vs.15.73%).Conclusions: Early-stage HER2-positive breast cancer patients treated with trastuzumab plus adjuvant chemotherapy have a significant survival benefit compared with chemotherapy-alone in real-world settings. Lymph node positivity, hormone receptor-negative status, and higher T stages may be associated with higher risks of recurrence, and effective therapy for patients with these factors is required.

Surgical resection of advanced gastric cancer following trastuzumab/oxaliplatin/capecitabine combination therapy

Late-stage gastric adenocarcinoma patients have a poor prognosis because of high recurrence rates. To improve long-term outcomes, perioperative chemotherapies are combined with surgery. Human epidermal growth factor receptor 2 (HER2) overexpression had been noted in gastric cancer; therefore, trastuzumab has been used occasionally in this setting. A 63-year-old male Chinese patient, who was diagnosed with adenocarcinoma in the gastric antrum, as well as lymph node metastases along the left gastric and hepatic artery, and left adrenal area, was admitted to our hospital. HER2 expression was positive, and cluster amplification was detected in a fluorescence in situ hybridization assay. The patient received three cycles of a neoadjuvant trastuzumab/oxaliplatin /capecitabine regimen. He subsequently underwent distal gastrectomy, D2+ lymphadenectomy, left adrenalectomy, cholecystectomy and Billroth II anastomosis. Treatment was continued with another five postoperative cycles of the same medication and trastuzumab application for 1 year. No recurrence has been observed 18 mo after the operation. Trastuzumab as perioperative and adjuvant medication, in combination with oxaliplatin and capecitabine for a HER2-overexpressing advanced gastric adenocarcinoma, led to recurrence-free survival of at least 18 mo after surgery.

Cardiac toxicity of trastuzumab in elderly patients with breast cancer

Breast cancer （BC） is diagnosed in 〉 65 year old women in about half of cases. Experts currently recommend that systemic therapy is offered to elderly patients with BC, if, based on their overall conditions and life expectancy, it can be reasonably anticipated that the benefits will outweigh the risks of treatment. Like for young subjects, the monoclonal antibody against human epidermal growth factor receptor-2 （HER-2）, trastuzumab, represents a valid therapeutic option when BC over-expresses this receptor. Unforttmately, administration of trastu- zumab is associated with the occurrence of left ventricular dysfunction and chronic heart failure （CHF）, possibly because of interference with the homeostatic functions of HER-2 in the heart. Registry-based, retrospective analyses have reported an incidence of CHF around 25% in elderly women receiving trastuzumab compared with 10%-15% in those not given any therapy for BC, and the risk of CHF has been estimated to be two-fold higher in 〉 60455 year old trastuzumab users vs. non-users. Extremely advanced age and preexisting cardiac disease have been shown to predispose to trastuzumab cardiotoxicity. Therefore, selection of older patients for treatment with trastuzumab should be primarily based on their general status and the presence of comorbidities; previous chemotherapy, especially with anthracyclines, should be also taken into account. Once therapy has started, efforts should be made to ensure regular cardiac surveillance. The role of selected biomarkers, such as cardiac troponin, or new imaging techniques （three-dimension, tissue Doppler echocardiography, magnetic resonance imaging） is promising, but must be further investigated especially in the elderly. Moreover, additional studies are needed in order to better understand the mechanisms by which trastuzumab affects the old heart.

检测恒河猴血清中trastuzumab浓度的一种直接酶联免疫竞争法(英)

采用ELISA法建立检测恒河猴血清中trastuzumab的酶联免疫竞争法,为研究人体内trastuzumab的药物动力学学和药效学提供依据。方法的测量范围是1～100μg/mL,最低检测限为1.0μg/mL。板内精密度范围91%～107%,相对标准偏差为1.5%～4.9%。板间精密度范围102%～110%,相对标准偏差为2.7%～15.4%。方法中未显示与重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白、重组抗CD20单克隆抗体、丙种球蛋白等的交叉反应。此方法的特异性、灵敏度、精密度和准确度均满足恒河猴血清样品的分析,是检测猴和人体内trastuzumab的理想方法。

Maintenance treatment of trastuzumab for patients with advanced breast cancer to achieve long term survival: two case reports and literature review

Molecular subtyping of breast cancer may provide additional prognostic information regarding patient outcome. The epidermal growth factor receptor （HER2） overexpressing breast cancers are designated as HER2-postive （HER2＋） breast cancer and carry a particularly unfavorable prognosis. We present two cases of HER2-postive metastatic breast cancer （MBC） who are found to be a challenge to treat, especially due to the occurrence of brain metastasis. Trastuzumab-based therapy improves clinical outcomes, even if the patient has undergone multi-line treatment. These case reports also emphasize the importance of retesting HER2 status because it can be discordance in receptor status between primary and recurrent breast cancer.

Effect of Trastuzumab on Notch-1 Signaling Pathway in Breast Cancer SK-BR3 Cells

Objective： To investigate the effects and mechanisms of trastuzumab on Notch-1 pathway in breast cancer cells, recognizing the significance of Notch-1 signaling pathway in trastuzumab resistance. Methods： Immunocytochemistry staining and Western blotting were employed to justify the expression of Notch-1 protein in HER2-overexpressing SK-BR3 cells and HER2-non-overexpressing breast cancer MDA-MB-231 cells. Western blotting and reverse transcription PCR （RT-PCR） were used to detect the activated Notch-1 and Notch-1 target gene HES-1 mRNA expression after SK-BR3 cells were treated with trastuzumab. Double immunofluorescence staining and co-immunoprecipitation were used to analyze the relationship of Notch-1 and HER2 proteins. Results： The level of Notch-1 nuclear localization and activated Notch-1 proteins in HER2-overexpressing cells were significantly lower than in HER2-non-overexpressing cells （P0.01）, and the expressions of activated Notch-1 and HES-1 mRNA were obviously increased after trastuzumab treatment （P0.05）, but HER2 expression did not change significantly for trastuzumab treating （P0.05）. Moreover, Notch-1 was discovered to co-localize and interact with HER2 in SK-BR3 cells. Conclusion： Overexpression of HER2 decreased Notch-1 activity by the formation of a HER2-Notch1 complex, and trastuzumab can restore the activity of Notch-1 signaling pathway, which could be associated with cell resistance to trastuzumab.

Preclinical characterization and validation of a dual-labeled trastuzumab-based imaging agent for diagnosing breast cancer

Objective： The combination of both nuclear and fluorescent reporters provides unique opportunities for noninvasive nuclear imaging with subsequent fluorescence image-guided resection and pathology. Our objective was to synthesize and optimize a dual-labeled trastuzumab-based imaging agent that can be used to validate an optical imaging agent with potential use in identifying tumor metastases in human epidermal growth factor receptor 2 （HER2） positive breast cancer patients. Methods： [111In]-DTPA-trastuzumab-IRDye 800 was synthesized by a three-step procedure. Purity, stability, immunoreactivity, internalization and biodistribution were explored in HER2＋ SKBR-3 cells. Biodistribution of [111In]-DTPA-trastuzumab-IRDye 800 was performed in a SKBR-3 xenograft model. Results： [111In]-DTPA-trastuzumab-IRDye 800 demonstrated high purity by both chemical and fluorometric determinations. Both flow cytometry and the Lindmo assay demonstrated a high binding affinity of [111In]-DTPA-trastuzumab-IRDye 800 to HER2-overexpressing cells. The dual-labeled conjugate was stable in PBS, but not in serum after 24 h at 37 ℃. Larger molecules （〉150 kD） were seen after a 24 h-incubation in human serum. Biodistribution studies revealed tumor-specific accumulation of [111In]-DTPA- trastuzumab-IRDye 800 in SKBR-3 tumors, and tumor uptakes at 24 and 48 h were （12.42±1.72）% and （9.96±1.05） %, respectively, following intravenous administration. The tumor-to-muscle ratio was 9.13±1.68 at 24 h, and increased to 12.79±2.13 at 48 h. Liver and kidney showed marked uptake of the dual-labeled imaging agent. Conclusions： [111In]-DTPA-trastuzumab-IRDye 800 is an effective diagnostic biomarker that can be used to validate dual-labeled, molecularly targeted imaging agents and can allow these agents to be translated into clinical practice for identifying HER2＋ lesions.

Complete response to trastuzumab and chemotherapy in recurrent urothelial bladder carcinoma with HER2 gene amplification: A case report

BACKGROUND Targeted treatments may greatly affect the natural history of urothelial carcinoma based on their pharmacokinetics. A phase II trial has explored the combination of cytotoxic chemotherapy with the anti-HER-2 monoclonal antibody trastuzumab in selected patients with metastatic bladder cancer, but it failed.CASE SUMMARY Here, we report a case of recurrent urothelial bladder carcinoma(UBC) in a patient who has undergone three operations, and further illuminate its diagnosis and treatment. The diagnosis of UBC was rendered according to the pathological indices. Next-generation sequencing on formalin fixed paraffin-embedded(FFPE)tissue was also performed and suggested HER2 gene amplification in the FFPE tissue. Based on HER2 gene amplification in FFPE, the patient was treated with chemotherapy in combination with trastuzumab after his third surgery.Fortunately, the patient got a clinically complete remission to trastuzumab for 34 mo.CONCLUSION There is not enough clinical evidence for incorporating trastuzumab in routine treatment of UBC. This case hinted that recurrent UBC patients with HER2 gene amplification may benefit from targeted trastuzumab. Further studies are needed to further investigate the status of HER2 gene and better determine trastuzumab in the management of UBC.