Obesity Suppresses Estrogen Receptor Beta Expression in Breast Cancer Cells via a HER2-Mediated Pathway

Obesity is associated with a worse breast cancer prognosis, while greater breast tumor estrogen receptor beta (ERβ) expression is correlated with improved therapy response and survival. The objective of this study was to determine the impact of obesity on breast cancer cell ERβ expression, which is currently unknown. We utilized an in vitro model of obesity in which breast cancer cells were exposed to patient serum pooled by body mass index category (obese (OB): ≥30 kg/m²; normal weight (N): 18.5–24.9 kg/m²). Four human mammary tumor cell lines representing the major breast cancer subtypes (SKBR3, MCF-7, ZR75, MDA-MB-231) and mammary tumor cells from MMTV-neu mice were used. ERβ expression, assessed by qPCR and western blotting, was suppressed in the two HER2-overexpressing cell lines (SKBR3, MMTV-neu) following OB versus N sera exposure, but did not vary in the other cell lines. Expression of Bcl-2 and cyclin D1, two genes negatively regulated by ERβ, was elevated in SKBR3 cells following exposure to OB versus N sera, but this difference was eliminated when the ERβ gene was silenced with siRNA. Herceptin, a HER2 antagonist, and siRNA to HER2 were used to evaluate the role of HER2 in sera-induced ERβ modulation. SKBR3 cell treatment with OB sera plus Herceptin increased ERβ expression three-fold. Similar results were obtained when HER2 expression was silenced with siRNA. OB sera also promoted greater SKBR3 cell viability and growth, but this variance was not present when ERβ was silenced or the cells were modified to overexpress ERβ. Based on this data, we conclude that obesity-associated systemic factors suppress ERβ expression in breast cancer cells via a HER2-mediated pathway, leading to greater cell viability and growth. Elucidation of the mechanism(s) mediating this effect could provide important insights into how ERβ expression is regulated as well as how obesity promotes a more aggressive disease.     

Estrogen Receptor and HER2 Status on Disseminated Tumor Cells and Primary Tumor in Patients with Early Breast Cancer

BACKGROUND: We evaluated both estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status on disseminated tumor cells (DTCs) in the bone marrow of 54 patients with early breast cancer and compared these with the corresponding primary tumor (PT). MATERIALS AND METHODS: Bone marrow aspirates were obtained at the time of first surgery, and ER and HER2 status on DTCs was assessed simultaneously by immunocytochemistry using a triple fluorescence staining method. RESULTS: The median number of DTCs was 13 (range 1-95). The concordance rate between ER status on DTC and PT was 74%. Patients with an ER-positive PT were significantly more likely to have at least one ER-positive DTC (34 out of 42) than patients with an ER-negative PT (6 out of 12; P = .031). Thirty-nine (93%) of the 42 patients with ER-positive PT had at least one ER-negative DTC. The concordance rate between HER2 status on DTC and PT was 52%. The probability of having at least one HER2-positive DTC was not related to the HER2 status of the PT (P = 0.56). Twenty-two (46%) of the 48 patients with a HER2-negative PT had at least one HER2-positive DTC. All the six patients with a HER2-positive PT had at least one HER2-negative DTC. CONCLUSION: Taken together, our study confirms that ER and/or HER2 status may differ between DTC and PT. This discordance could be important for patients lacking ER or HER2 expression on the PT but showing ER-positive or HER2-positive DTC because they might benefit from an endocrine and/or HER2-targeted therapy.     

乳腺癌细胞表皮生长因子受体、HER-2对雌激素受体的调控及三苯氧胺耐药机制

雌激素受体(ER)在乳腺癌的发生和发展中起重要作用,抗雌激素治疗的内分泌治疗为重要的治疗方案,但易产生三苯氧胺(TAM)的耐药性而使治疗失效,原因之一可能是由于表皮生长因子受体(EGFR)和HER-2高表达引起ER磷酸化所致。本文概述了其中的分子机制和可能涉及的传导通路等。     

乳腺癌人类表皮生长因子受体2表达与X线表现的相关性分析

目的：对比分析人类表皮生长因子受体2（HER-2）阳性和阴性乳腺癌X线特征,探讨乳腺癌X线征象与HER-2基因之间的相关性。方法：回顾性分析经手术病理确诊的1153例女性乳腺癌患者的X线表现,根据免疫组织化学结果分为HER-2阳性组（314例）和HER-2阴性组（839例）。对比分析两组乳腺癌肿块和钙化的X线特征,肿块主要分析形态、边界及边缘,钙化主要分析形状及分布形式,并对各项分析结果进行X2检验,P〈0.05为差异性有统计学意义。结果：HER-2阳性组乳腺癌较阴性组多表现为钙化（X2=42.528,P=0.001）,HER-2阴性组乳腺癌X线表现多为单纯肿块（389/839,X2=16.374,P=0.001）。星芒状肿块在HER-2阴性组比例较高（57/514,X2=5.912,P=0.015）,两组类圆形（P=0.480）、分叶状（P=0.111）、不规则形肿块（P=0.152）分布比例则无明显统计学差异。HER-2阳性组乳腺癌肿块边界多模糊不清（X2=8.319,P=0.004）,阴性组肿块边界多为部分清楚（X2=5.818,P=0.016）。HER-2阳性组乳腺癌钙化形态多表现为沙砾状（X2=8.955,P=0.001）、多形性和不定形（X2=7.137,P=0.001）,分布形式无明显统计学差异。结论：HER-2阳性乳腺癌X线表现钙化居多,且多为沙砾状、多形性和不定形钙化,肿块边界多模糊不清;HER-2阴性乳腺癌多表现为单纯肿块,边界多为部分清楚,星芒状肿块多见。     

Aptamer-Assisted Detection of the Altered Expression of Estrogen Receptor Alpha in Human Breast Cancer

An increase in the expression of estrogen receptors (ER) and the expanded population of ER-positive cells are two common phenotypes of breast cancer. Detection of the aberrantly expressed ERα in breast cancer is carried out using ERα-antibodies and radiolabelled ligands to make decisions about cancer treatment and targeted therapy. Capitalizing on the beneficial advantages of aptamer over the conventional antibody or radiolabelled ligand, we have identified a DNA aptamer that selectively binds and facilitates the detection of ERα in human breast cancer tissue sections. The aptamer is identified using the high throughput sequencing assisted SELEX screening. Biophysical characterization confirms the binding and formation of a thermodynamically stable complex between the identified DNA aptamer (ERaptD4) and ERα (Ka = 1.55±0.298×10⁸ M^-1; ΔH = 4.32×10⁴±801.1 cal/mol; ΔS = -108 cal/mol/deg). Interestingly, the specificity measurements suggest that the ERaptD4 internalizes into ERα-positive breast cancer cells in a target-selective manner and localizes specifically in the nuclear region. To harness these characteristics of ERaptD4 for detection of ERα expression in breast cancer samples, we performed the aptamer-assisted histochemical analysis of ERα in tissue samples from breast cancer patients. The results were validated by performing the immunohistochemistry on same samples with an ERα-antibody. We found that the two methods agree strongly in assay output (kappa value = 0.930, p-value <0.05 for strong ERα positive and the ERα negative samples; kappa value = 0.823, p-value <0.05 for the weak/moderate ER+ve samples, n = 20). Further, the aptamer stain the ERα-positive cells in breast tissues without cross-reacting to ERα-deficient fibroblasts, adipocytes, or the inflammatory cells. Our results demonstrate a significant consistency in the aptamer-assisted detection of ERα in strong ERα positive, moderate ERα positive and ERα negative breast cancer tissues. We anticipate that the ERaptD4 aptamer targeting ERα may potentially be used for an efficient grading of ERα expression in cancer tissues.     

Expression of Autophagy-Related Proteins According to Androgen Receptor and HER-2 Status in Estrogen Receptor-Negative Breast Cancer

Purpose

The purpose of this study was to investigate the expression of autophagy-related proteins in relation to androgen receptor (AR) status in estrogen receptor (ER)-negative breast cancers.

Methods

We extracted 334 ER-negative breast cancer samples to construct tissue microarrays (TMAs), which were immunohistochemically stained for autophagy-related proteins (beclin-1, LC3A, LC3B, p62) and for AR and HER-2.

Results

There were 127 AR-positive cases and 207 AR-negative cases, and 140 HER-2-positive cases and 194 HER-2 negative cases. The AR-negative group was associated with tumoral LC3A expression (P<0.001), while the AR-positive group was associated with tumoral BNIP3 expression (P<0.001). Tumoral LC3A was most highly expressed in the AR-negative and HER-2 negative group, while stromal LC3A showed the highest expression in the AR-negative and HER-2-positive group. Tumoral BNIP3 and stromal BNIP3 were highest in the AR-positive and HER-2-negative group. In the AR-positive and HER-2-negative group, stromal p62 positivity was an independent factor that was statistically significant in its association with shorter disease-free survival (DFS) (Hazard ratio: 10.21, 95% CI: 1.130–92.31, P = 0.039). Shorter DFS was associated with tumoral LC3A positivity (Hazard ratio: 10.28, 95% CI: 2.068–51.19, P = 0.004) in the AR-negative and HER-2-positive group.

Conclusion

In ER-negative breast cancers, AR status was associated with expression of different types of autophagy-related proteins. Tumoral LC3A was most highly expressed in AR-negative breast cancers, while tumor BNIP3 was highest in AR-positive breast cancers.     

Estrogen Receptor Expression Is Associated with DNA Repair Capacity in Breast Cancer

Estrogen-receptor-positive (ER+) tumors employ complex signaling that engages in crosstalk with multiple pathways through genomic and non-genomic regulation. A greater understanding of these pathways is important for developing improved biomarkers that can better determine treatment choices, risk of recurrence and cancer progression. Deficiencies in DNA repair capacity (DRC) is a hallmark of breast cancer (BC); therefore, in this work we tested whether ER signaling influences DRC. We analyzed the association between ER positivity (% receptor activation) and DRC in 270 BC patients, then further stratified our analysis by HER2 receptor status. Our results show that among HER2 negative, the likelihood of having low DRC values among ER- women is 1.92 (95% CI: 1.03, 3.57) times the likelihood of having low DRC values among ER+ women, even adjusting for different potential confounders (p<0.05); however, a contrary pattern was observed among HER2 positives women. In conclusion, there is an association between DRC levels and ER status, and this association is modified by HER2 receptor status. Adding a DNA repair capacity test to hormone receptor testing may provide new information on defective DNA repair phenotypes, which could better stratify BC patients who have ER+ tumors. ER+/HER2- tumors are heterogeneous, incompletely defined, and clinically challenging to treat; the addition of a DRC test could better characterize and classify these patients as well as help clinicians select optimal therapies, which could improve outcomes and reduce recurrences.     

雌激素受体β在乳腺癌生长中的作用研究进展

雌激素受体 β(ERβ) 是雌激素受体的另一亚型。众多体内外实验证明,ERβ 与乳腺癌的生长有密切联系。ERβ 低表达会促进乳腺 癌增殖,介导转移,还能抑制乳腺癌细胞的凋亡。临床数据证明,ERβ 在乳腺癌患者的癌旁组织中表达高于癌组织,且与乳腺癌患者的 总生存率相关。ERβ 与雌激素受体 α(ERα)、表皮生长因子受体(EGFR)、孕激素受体(PR)均有密切联系:ERα 和 ERβ mRNA 平 均表达水平比值(ERβ/ERα)升高,对抗癌药物有拮抗作用,反之则有协同作用;ERβ 的表达量受 PR 调节,并能通过 EGFR 及下游信 号通路,抑制上皮-间充质转化。临床乳腺癌样本表明,ERβ 低表达可能与启动子甲基化有关。因此,采用药物调节 ERβ 的表达以及敏感性, 是具有很大临床价值的潜在治疗手段。综述 ERβ 以及 ERβ 与相关受体之间的联系在乳腺癌生长中的作用。     

Adjuvant Trastuzumab in HER2-Positive Early Breast Cancer by Age and Hormone Receptor Status: A Cost-Utility Analysis

BackgroundThe anti–human epidermal growth factor receptor 2 (HER2) monoclonal antibody trastuzumab improves outcomes in patients with node-positive HER2+ early breast cancer. Given trastuzumab’s high cost, we aimed to estimate its cost-effectiveness by heterogeneity in age and estrogen receptor (ER) and progesterone receptor (PR) status, which has previously been unexplored, to assist prioritisation.ConclusionsThis study highlights how cost-effectiveness can vary greatly by heterogeneity in age and hormone receptor subtype. Resource allocation and licensing of subsidised therapies such as trastuzumab should consider demographic and clinical heterogeneity; there is currently a profound disconnect between how funding decisions are made (largely agnostic to heterogeneity) and the principles of personalised medicine.     

Interaction of Vault Particles with Estrogen Receptor in the MCF-7 Breast Cancer Cell

A 104-kD protein was coimmunoprecipitated with the estrogen receptor from the flowtrough of a phosphocellulose chromatography of MCF-7 cell nuclear extract. mAbs to this protein identified several cDNA clones coding for the human 104-kD major vault protein. Vaults are large ribonucleoprotein particles of unknown function present in all eukaryotic cells. They have a complex morphology, including several small molecules of RNA, but a single protein species, the major vault protein, accounts for >70% of their mass. Their shape is reminiscent of the nucleopore central plug, but no proteins of known function have been described to interact with them. Western blot analysis of vaults purified on sucrose gradient showed the presence of estrogen receptor co-migrating with the vault peak. The AER317 antibody to estrogen receptor coimmunoprecipitated the major vault protein and the vault RNA also in the 20,000 g supernatant fraction. Reconstitution experiments of estrogen receptor fragments with the major vault protein mapped the site of the interaction between amino acids 241 and 280 of human estrogen receptor, where the nuclear localization signal sequences are located. Estradiol treatment of cells increased the amount of major vault protein present in the nuclear extract and coimmunoprecipitated with estrogen receptor, whereas the anti-estrogen ICI182,780 had no effect. The hormone-dependent interaction of vaults with estrogen receptor was reproducible in vitro and was prevented by sodium molybdate. Antibodies to progesterone and glucocorticoid receptors were able to coimmunoprecipitate the major vault protein. The association of nuclear receptors with vaults could be related to their intracellular traffic.     

Support Vector Machine Classifier for Estrogen Receptor Positive and Negative Early-Onset Breast Cancer

Two major breast cancer sub-types are defined by the expression of estrogen receptors on tumour cells. Cancers with large numbers of receptors are termed estrogen receptor positive and those with few are estrogen receptor negative. Using genome-wide single nucleotide polymorphism genotype data for a sample of early-onset breast cancer patients we developed a Support Vector Machine (SVM) classifier from 200 germline variants associated with estrogen receptor status (p<0.0005). Using a linear kernel Support Vector Machine, we achieved classification accuracy exceeding 93%. The model indicates that polygenic variation in more than 100 genes is likely to underlie the estrogen receptor phenotype in early-onset breast cancer. Functional classification of the genes involved identifies enrichment of functions linked to the immune system, which is consistent with the current understanding of the biological role of estrogen receptors in breast cancer.     

Efficacy of Histone Deacetylase and Estrogen Receptor Inhibition in Breast Cancer Cells Due to Concerted down Regulation of Akt

Hormonal therapy resistance remains a considerable barrier in the treatment of breast cancer. Activation of the Akt-PI3K-mTOR pathway plays an important role in hormonal therapy resistance. Our recent preclinical and clinical studies showed that the addition of a histone deacetylase inhibitor re-sensitized hormonal therapy resistant breast cancer to tamoxifen. As histone deacetylases are key regulators of Akt, we evaluated the effect of combined treatment with the histone deacetylase inhibitor PCI-24781 and tamoxifen on Akt in breast cancer cells. We demonstrate that while both histone deacetylase and estrogen receptor inhibition down regulate AKT mRNA and protein, their concerted effort results in down regulation of AKT activity with induction of cell death. Histone deacetylase inhibition exerts its effect on AKT mRNA through an estrogen receptor-dependent mechanism, primarily down regulating the most abundant isoform AKT1. Although siRNA depletion of AKT modestly induces cell death, when combined with an anti-estrogen, cytotoxicity is significantly enhanced. Thus, histone deacetylase regulation of AKT mRNA is a key mediator of this therapeutic combination and may represent a novel biomarker for predicting response to this regimen.     

过表达ER恢复雌激素对子宫内膜癌KLE细胞中Notch信号通路的调控

目的:通过观察雌激素对子宫内膜癌KLE细胞中Notch信号通路的影响,探讨过表达雌激素核受体（estrogen receptor,ER）是否可以恢复雌激素对Notch信号通路的调控作用,继而调节细胞增殖活性。方法:MTT检测雌激素及Notch信号通路对细胞增殖活性的影响;RT-PCR及Western-blotting检测雌激素及Notch通路抑制剂DAPT对Notch表达的影响;质粒的抽提及转染使KLE细胞中的雌激素核受体ER过表达。结果:雌激素呈剂量依赖效应促进KLE细胞的增殖活性,其中以雌激素浓度为1.0×10^-9M时最明显（相对于对照组为1.25±0.026,P<0.05）;抑制Notch信号通路的表达可以明显下调KLE细胞的增殖活性（0.76±0.02,P<0.05）;在KLE细胞中,雌激素对Notch的表达没有明显的调控作用,但是将其雌激素核受体过表达后,雌激素可明显上调Notch的表达,并显著促进细胞的增殖活性（1.24±0.02,P<0.05）。结论:在ER阴性的子宫内膜癌细胞中过表达ER,可以恢复雌激素对Notch信号通路的调控,从而进一步的调控细胞增殖活性。     

过表达ER恢复雌激素对子宫内膜癌KLE细胞中Notch信号通路的调控

目的：通过观察雌激素对子宫内膜癌KLE细胞中Notch信号通路的影响,探讨过表达雌激素核受体（estrogenreceptor,ER）是否可以恢复雌激素对Notch信号通路的调控作用,继而调节细胞增殖活性。方法：MTT检测雌激素及Notch信号通路对细胞增殖活性的影响;RT．PCR及Westem．blotting检测雌激素及Notch通路抑制剂DAPT对Notch表达的影响;质粒的抽提及转染使KLE细胞中的雌激素核受体ER过表达。结果：雌激素呈剂量依赖效应促进KLE细胞的增殖活性,其中以雌激素浓度为1．0×10-9M时最明显（相对于对照组为1．25±0．026,P〈0．05）;抑制Notch信号通路的表达可以明显下调KLE细胞的增殖活性（0．76±0．02,P〈0．05）;在KLE细胞中,雌激素对Notch的表达没有明显的调控作用,但是将其雌激素核受体过表达后,雌激素可明显上调Notch的表达,并显著促进细胞的增殖活性（1．24±0．02,P〈0．05）。结论：在ER阴性的子宫内膜癌细胞中过表达ER,可以恢复雌激素对Notch信号通路的调控,从而进一步的调控细胞增殖活性。     

Expression of NgBR Is Highly Associated with Estrogen Receptor Alpha and Survivin in Breast Cancer

NgBR is a type I receptor with a single transmembrane domain and was identified as a specific receptor for Nogo-B. Our recent findings demonstrated that NgBR binds farnesylated Ras and recruits Ras to the plasma membrane, which is a critical step required for the activation of Ras signaling in human breast cancer cells and tumorigenesis. Here, we first use immunohistochemistry and real-time PCR approaches to examine the expression patterns of Nogo-B and NgBR in both normal and breast tumor tissues. Then, we examine the relationship between NgBR expression and molecular subtypes of breast cancer, and the roles of NgBR in estrogen-dependent survivin signaling pathway. Results showed that NgBR and Nogo-B protein were detected in both normal and breast tumor tissues. However, the expression of Nogo-B and NgBR in breast tumor tissue was much stronger than in normal breast tissue. The statistical analysis demonstrated that NgBR is highly associated with ER-positive/HER2-negative breast cancer. We also found that the expression of NgBR has a strong correlation with the expression of survivin, which is a well-known apoptosis inhibitor. The correlation between NgBR and survivin gene expression was further confirmed by real-time PCR. In vitro results also demonstrated that estradiol induces the expression of survivin in ER-positive T47D breast tumor cells but not in ER-negative MDA-MB-468 breast tumor cells. NgBR knockdown with siRNA abolishes estradiol-induced survivin expression in ER-positive T47D cells but not in ER-negative MDA-MB-468 cells. In addition, estradiol increases the expression of survivin and cell growth in ER-positive MCF-7 and T47D cells whereas knockdown of NgBR with siRNA reduces estradiol-induced survivin expression and cell growth. In summary, these results indicate that NgBR is a new molecular marker for breast cancer. The data suggest that the expression of NgBR may be essential in promoting ER-positive tumor cell proliferation via survivin induction in breast cancer.     

Breast Cancer Incidence in Black and White Women Stratified by Estrogen and Progesterone Receptor Statuses

Background

There is increasing evidence that breast cancer is a heterogeneous disease presented by different phenotypes and that white women have a higher breast cancer incidence rate, whereas black women have a higher mortality rate. It is also well known that white women have lower incidence rates than black women until approximately age 40, when rate curves cross over and white women have higher rates. The goal of this study was to validate the risk of white and black women to breast cancer phenotypes, stratified by statuses of the estrogen (ER) and progesterone (PR) receptors.

Methodology/Principal Findings

SEER17 data were fractioned by receptor status into [ER+, PR+], [ER−, PR−], [ER+, PR−], and [ER−, PR+] phenotypes. It was shown that in black women compared to white women, cumulative age-specific incidence rates are: (i) smaller for the [ER+, PR+] phenotype; (ii) larger for the [ER−, PR−] and [ER−, PR+] phenotypes; and (iii) almost equal for the [ER+, PR−] phenotype. Clemmesen''s Hook, an undulation unique to women''s breast cancer age-specific incidence rate curves, is shown here to exist in both races only for the [ER+, PR+] phenotype. It was also shown that for all phenotypes, rate curves have additional undulations and that age-specific incidence rates are nearly proportional in all age intervals.

Conclusions/Significance

For black and white women, risk for the [ER+, PR+], [ER−, PR−] and [ER−, PR+] phenotypes are race dependent, while risk for the [ER+, PR−] phenotype is almost independent of race. The processes of carcinogenesis in aging, leading to the development of each of the considered breast cancer phenotypes, are similar in these racial groups. Undulations exhibited on the curves of age-specific incidence rates of the considered breast cancer phenotypes point to the presence of several subtypes (to be determined) of each of these phenotypes.     

A Mathematical Model for the Effects of HER2 Overexpression on Cell Proliferation in Breast Cancer

We present a mathematical model to study the effects of HER2 over-expression on cell proliferation in breast cancer. The model illustrates the proliferative behavior of cells as a function of HER2 and EGFR receptors numbers, and the growth factor EGF. This mathematical model comprises kinetic equations describing the cell surface binding of EGF growth factor to EGFR and HER2 receptors, coupled to a model for the dependence of cell proliferation rate on growth factor receptors binding. The simulation results from this model predict: (1) a growth advantage associated with excess HER2 receptors; (2) that HER2-over-expression is an insufficient parameter to predict the proliferation response of cancer cells to epidermal growth factors; and (3) the EGFR receptor expression level in HER2-over-expressing cells plays a key role in mediating the proliferation response to receptor-ligand signaling. This mathematical model also elucidates the interaction and roles of other model parameters in determining cell proliferation rate of HER2-over-expressing cells.     

Efficacy and Safety of HER2-Targeted Agents for Breast Cancer with HER2-Overexpression: A Network Meta-Analysis

BackgroundClinical trials of human epidermal growth factor receptor 2 (HER2)-targeted agents added to standard treatment have been efficacious for HER2-positive (HER2+) advanced breast cancer. To our knowledge, no meta-analysis has evaluated HER2-targeted therapy including trastuzumab emtansine (T-DM1) and pertuzumab for HER2-positive breast caner and ranked the targeted treatments. We performed a network meta-analysis of both direct and indirect comparisons to evaluate the effect of adding HER2-targeted agents to standard treatment and examined side effects.MethodsWe performed a Bayesian-framework network meta-analysis of randomized controlled trials to compare 6 HER2-targeted treatment regimens and 1 naïve standard treatment (NST, without any-targeted drugs) in targeted treatment of HER2+ breast cancer in adults. These treatment regimens were T-DM1, LC (lapatinib), HC (trastuzumab), PEC (pertuzumab), LHC (lapatinib and trastuzumab), and PEHC (pertuzumab and trastuzumab). The main outcomes were overall survival and response rates. We also examined side effects of rash, LVEF (left ventricular ejection fraction), fatigue, and gastrointestinal disorders, and performed subgroup analysis for the different treatment regimens in metastatic or advanced breast cancer.ResultsWe identified 25 articles of 21 trials, with data for 11,276 participants. T-DM1 and PEHC were more efficient drug regimens with regard to overall survival as compared with LHC, LC, HC and PEC. The incidence of treatment-related rash occurs more frequently in the patients who received LC treatment regimen than PEHC and T-DM1 and HC. In subgroup analysis, T-DM1 was associated with increased overall survival as compared with LC and HC. PEHC was associated with increased overall response as compared with LC, HC, and NST.ConclusionsOverall, the regimen of T-DM1 as well as pertuzumab in combination with trastuzumab and docetaxel is efficacious with fewer side effects as compared with other regimens, especially for advanced HER2+ breast cancer.ImpactThis study suggests that both T-DM1 and PEHC therapy are potentially and equally useful treatments for HER2+ breast cancer.     

Co-Targeting of JNK and HUNK in Resistant HER2-Positive Breast Cancer

Strategies for successful primary treatment of HER2-positive breast cancer include use of the HER2 inhibitors trastuzumab or lapatinib in combination with standard chemotherapy. While successful, many patients develop resistance to these HER2 inhibitors indicating an unmet need. Consequently, current research efforts are geared toward understanding mechanisms of resistance and the signaling modalities that regulate these mechanisms. We have undertaken a study to examine whether signaling molecules downstream of epidermal growth factor receptor, which often act as compensatory signaling outlets to circumvent HER2 inhibition, can be co-targeted to overcome resistance. We identified JNK signaling as a potential area of intervention and now show that inhibiting JNK using the pan-JNK inhibitor, SP600125, is effective in the HER2-positive, resistant JIMT-1 xenograft mammary tumor model. We also investigate potential combination strategies to bolster the effects of JNK inhibition and find that co-targeting of JNK and the protein kinase HUNK can prohibit tumor growth of resistant HER2-positive mammary tumors in vivo.