Colorimetric Detection of HER2-Overexpressing-Cancer-Derived Exosomes in Mouse Urine Using Magnetic-Polydiacetylene Nanoparticles.

Breast cancer (BC) is a major global health problem, with ≈20-25% of patients overexpressing human epidermal growth factor receptor 2 (HER2), an aggressive marker, yet access to early detection and treatment varies across countries. A low-cost, equipment-free, and easy-to-use polydiacetylene (PDA)-based colorimetric sensor is developed for HER2-overexpressing cancer detection, designed for use in low- and middle-income countries (LMICs). PDA nanoparticles are first prepared through thin-film hydration. Subsequently, hydrophilic magnetic nanoparticles and HER2 antibodies are sequentially conjugated to them. The synthesized HER2-MPDA can be concentrated and separated by a magnetic field while inheriting the optical characteristics of PDA. The specific binding of HER2 antibody in HER2-MPDA to HER2 receptor in HER2-overexpressing exosomes causes a blue-to-red color change by altering the molecular structure of the PDA backbone. This colorimetric sensor can simultaneously separate and detect HER2-overexpressing exosomes. HER2-MPDA can detect HER2-overexpressing exosomes in the culture medium of HER2-overexpressing BC cells and in mouse urine samples from a HER2-overexpressing BC mouse model. It can selectively isolate and detect only HER2-overexpressing exosomes through magnetic separation, and its detection limit is found to be 8.5 × 108 particles mL-1. This colorimetric sensor can be used for point-of-care diagnosis of HER2-overexpressing BC in LMICs.

ß2-microglobulin induced apoptosis of tumor cells via the ERK signaling pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

BACKGROUND: Our previous study demonstrated that ß2-microglobulin (ß2M) promoted ER+/HER2- breast cancer survival via the SGK1/Bcl-2 signaling pathway. However, the role of ß2M has not been investigated in ER-/HER2+ breast cancer. Here, we aimed to determine the role of ß2M in ER-/HER2+ breast cancer. METHODS: The interaction between ß2M and HFE was confirmed by co-immunoprecipitation, mass spectrometry, yeast two-hybrid screening, and His pull-down. The knockdown and overexpression of ß2M or HFE were performed in MDA-MB-453 cells, and ERK signaling pathway was subsequently analyzed via western blotting. Apoptotic cells were detected using flow cytometer. ß2M, HFE, and p-ERK1/2 were examined in tumor and paired adjacent tissues via immunohistochemistry. RESULTS: HFE was found to be an interacting protein of ß2M in ER-/HER2+ breast cancer cells MDA-MB-453 by co-immunoprecipitation and mass spectrometry. A yeast two-hybrid system and His-pull down experiments verified that ß2M directly interacted with HFE. ß2M and HFE as a complex were mainly located in the cytoplasm, with some on the cytomembrane of MDA-MB-453 cells. In addition to breast cancer cells BT474, endogenous ß2M directly interacted with HFE in breast cancer cells MDA-MB-453, MDA-MB-231, and MCF-7. ß2M activated the ERK signaling pathway by interacting with HFE and induced apoptosis of MDA-MB-453 cells. The expression of HFE and p-ERK1/2 showed significantly high levels in HER2-overexpressing breast cancer tumor tissue compared with adjacent normal tissue, consistent with the results obtained from the cell experiments. CONCLUSIONS: ß2M induced apoptosis of tumor cells via activation of the ERK signal pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

Inhibiting HER3 Hyperphosphorylation in HER2-Overexpressing Breast Cancer through Multimodal Therapy with Branched Gold Nanoshells.

Treatment failure in breast cancers overexpressing human epidermal growth factor receptor 2 (HER2) is associated mainly to the upregulation of human epidermal growth factor receptor 3 (HER3) oncoprotein linked to chemoresitence. Therefore, to increase patient survival, here a multimodal theranostic nanoplatform targeting both HER2 and HER3 is developed. This consists of doxorubicin-loaded branched gold nanoshells functionalized with the near-infrared (NIR) fluorescent dye indocyanine green, a small interfering RNA (siRNA) against HER3, and the HER2-specific antibody Transtuzumab, able to provide a combined therapeutic outcome (chemo- and photothermal activities, RNA silencing, and immune response). In vitro assays in HER2+ /HER3+ SKBR-3 breast cancer cells have shown an effective silencing of HER3 by the released siRNA and an inhibition of HER2 oncoproteins provided by Trastuzumab, along with a decrease of the serine/threonine protein kinase Akt (p-AKT) typically associated with cell survival and proliferation, which helps to overcome doxorubicin chemoresistance. Conversely, adding the NIR light therapy, an increment in p-AKT concentration is observed, although HER2/HER3 inhibitions are maintained for 72 h. Finally, in vivo studies in a tumor-bearing mice model display a significant progressively decrease of the tumor volume after nanoparticle administration and subsequent NIR light irradiation, confirming the potential efficacy of the hybrid nanocarrier.

Adjuvant treatment with paclitaxel plus trastuzumab for node-negative breast cancer: real-life experience.

Background: In node-negative HER2-overexpressed breast cancers, adjuvant paclitaxel plus trastuzumab treatment is a successful de-escalation approach with excellent survival outcomes. Methods: All patients with HER2+ breast cancer treated in our centers were retrospectively reviewed. Results: We analyzed 173 patients who were treated with adjuvant paclitaxel plus trastuzumab. The mean tumor size was 2.2 cm. There were eight invasive disease events or death: four distant recurrences (2.3%), three locoregional recurrences (1.7%) and one death without documented recurrence after a 52 month follow-up. The 3-year disease-free survival and recurrence-free interval rate was 96.6%. Conclusion: This real-life experience with adjuvant paclitaxel plus trastuzumab demonstrated few distant recurrences and is compatible with the APT trial findings.

Lay abstract In oncology practice, there have been some efforts to avoid the toxicity of combination chemotherapies and reduce the amount of treatment given in recent decades. These strategies have been studied especially for patients with a specific subtype of early-stage breast cancer. We present the results from patients treated in our centers and discuss them in relation to the literature.

Antihypertensive medications and risks of recurrence and mortality in luminal, triple-negative, and HER2-overexpressing breast cancer.

PURPOSE: Antihypertensives are commonly prescribed medications and their effect on breast cancer recurrence and mortality is not clear, particularly among specific molecular subtypes of breast cancer: luminal, triple-negative (TN), and HER2-overexpressing (H2E). METHODS: A population-based prospective cohort study of women aged 20-69 diagnosed with a first primary invasive breast cancer between 2004 and 2015 was conducted in the Seattle, Washington and Albuquerque, New Mexico greater metropolitan areas. Multivariable-adjusted Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for risks of breast cancer recurrence, breast cancer-specific mortality, and all-cause mortality associated with hypertension and antihypertensives. RESULTS: In this sample of 2,383 luminal, 1,559 TN, and 615 H2E breast cancer patients, overall median age was 52 (interquartile range, 44-60). Hypertension and current use of antihypertensives were associated with increased risks of all-cause mortality in each subtype. Current use of angiotensin-converting enzyme inhibitors was associated with increased risks of both recurrence and breast cancer-specific mortality among luminal patients (HR: 2.5; 95% CI: 1.5, 4.3 and HR: 1.9; 95% CI: 1.2, 3.0, respectively). Among H2E patients, current use of calcium channel blockers was associated with an increased risk of breast cancer-specific mortality (HR: 1.8; 95% CI: 0.6, 5.4). CONCLUSION: Our findings suggest that some antihypertensive medications may be associated with adverse breast cancer outcomes among women with certain molecular subtypes. Additional studies are needed to confirm these findings.

Pathological complete response rates with pertuzumab-based neoadjuvant chemotherapy in breast cancer: A single-center experience.

BACKGROUND: Pertuzumab-based neoadjuvant chemotherapy (NAC) has demonstrated successful pathologic complete response (pCR) rates when administered to patients with human epidermal growth factor receptor 2 (HER2)-positive, locally advanced breast cancer and has become standard of care. This study aimed to identify pCR rates in patients receiving a variety of pertuzumab-based NAC regimens. The effect of the addition of an anthracycline and impact of anthracycline and taxane sequencing on pCR was also assessed. METHODS: A retrospective, single-center review was conducted on patients with operable, human epidermal growth factor receptor 2 (HER2)-positive breast cancer that received one of five pertuzumab-containing NAC regimens followed by definitive surgery. RESULTS: Ninety-six patients were included in the analysis; overall, pCR was attained in 49 patients (51%). Of the 61 patients who received an anthracycline-containing NAC regimen, 30 (49%) attained a pCR. Of the 35 patients who received the non-anthracycline NAC regimen, 19 (54%) attained a pCR; difference in pCR was not statistically significant (p = 0.63). Anthracycline/taxane sequence analysis showed that of the patients attaining pCR with an anthracycline-containing NAC, 77% of patients received the taxane portion upfront (p = 0.17). Relative dose intensity of the anthracycline portion was similar irrespective of treatment sequence. However, relative dose intensity of the taxane portion was decreased with upfront anthracycline administration. CONCLUSION: These findings support current recommendations of adding pertuzumab to established regimens for treatment of locally advanced, HER2-positive, early stage breast cancer. The benefit of adding an anthracycline in the neoadjuvant setting remains unclear. Patients treated with the taxane portion of NAC upfront appeared to have a higher rate of pCR and better relative dose intensity than patients who received the anthracycline portion upfront, but differences were not statistically significant. These findings should be verified in a prospective clinical trial.

Can trastuzumab emtansine be replaced by additional chemotherapy plus targeted therapy for HER2-overexpressing breast cancer patients with residual disease after neoadjuvant chemotherapy?

Human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer is an aggressive phenotype with a poor prognosis, and can easily metastasize and recur. Currently, chemotherapy plus HER2-targeted therapy is the standard systemic treatment for most of these patients. Given that neoadjuvant chemotherapy (NAC) has an efficacy equivalent to that of adjuvant chemotherapy and some additional benefits, many patients, especially those with more advanced tumors, prefer NAC and generally will not receive additional chemotherapy after surgery, irrespective of the pathological response. However, achieving pathological complete response to NAC is strongly correlated with prognosis, especially in triple-negative and HER2-overexpressing breast cancer. Therefore, postoperative treatment of these patients with residual diseases should be optimized to achieve favorable outcomes. The CREATE-X study has confirmed that additional chemotherapy can improve the outcomes of patients with HER2-negative residual disease after NAC. In addition, chemotherapy plays an indispensable role in the treatment of patients who receive surgery directly or who have recurrent lesions. Therefore, can additional chemotherapy improve prognosis of patients with HER2-overexpressing residual breast cancer? At present, no studies have compared the efficacy of additional chemotherapy plus trastuzumab with that of anti-HER2 therapy alone in residual cancer. The KATHERINE study revealed that trastuzumab emtansine (T-DM1) can reduce the risk of recurrence or death by 50% compared with trastuzumab in patients with HER2-positive residual invasive breast cancer after neoadjuvant therapy. T-DM1 is an antibody-drug conjugate of trastuzumab and the cytotoxic agent emtansine, and thus, to an extent, T-DM1 is equivalent to simultaneous application of chemotherapy and targeted therapy. However, high cost and low accessibility limit its use especially in low- and middle-income countries and regions. Hence, we proposed this perspective that additional chemotherapy plus trastuzumab should be given to HER2-overexpressing breast cancer patients with residual disease after NAC to improve their prognosis by discussing that the efficacy of additional chemotherapy plus trastuzumab is superior to that of anti-HER2 therapy alone and not inferior to T-DM1. Additional chemotherapy plus trastuzumab-based HER2-targeted therapy can be used as an alternative regimen to T-DM1 when T-DM1 is unavailable. However, further clinical research on the selection of chemotherapeutic agents is warranted.

Alcohol, smoking, and risk of Her2-overexpressing and triple-negative breast cancer relative to estrogen receptor-positive breast cancer.

Epidemiological evidence is limited on how alcohol consumption and smoking are associated with risk of different subtypes of breast cancer, such as triple-negative (TN) and human epidermal growth factor receptor 2-overexpressing (H2E) breast cancers, which may have different etiologies from more common luminal (estrogen receptor [ER+]) breast cancers. In this population-based case-case study, we evaluated the association between alcohol, smoking, and risk of H2E and TN breast cancer, compared with ER+ breast cancers, among women aged 20-69 years. Using polytomous regression, associations between alcohol consumption, smoking, and breast cancer risk were evaluated in 909 ER+, 1,290 TN, and 489 H2E breast cancer patients, with ER+ breast cancer patients as the reference group. Current alcohol consumption at diagnosis was associated with a lower risk of H2E breast cancer (odds ratio = 0.74, 95% confidence interval: 0.58-0.92) relative to ER+ cancers. No difference in association was observed by menopausal status. No association between alcohol consumption and TN breast cancer relative to ER+ breast cancer was observed. Women who smoked did not have an altered risk of TN or H2E breast cancer, relative to ER+ cancer. Our results suggest that alcohol is associated with lower risk of H2E breast cancer relative to ER+ breast cancer. This study adds to the body of epidemiologic evidence that breast cancer etiology differs by breast cancer subtype.

A non-randomized dose-escalation Phase I trial of a protein-based immunotherapeutic for the treatment of breast cancer patients with HER2-overexpressing tumors.

This Phase I dose-escalation study (NCT00058526) assessed the safety and immunogenicity of an anti-cancer immunotherapeutic (recombinant HER2 protein (dHER2) combined with the immunostimulant AS15) in patients with early-stage HER2-overexpressing breast cancer (BC). Sixty-one trastuzumab-naive patients with stage II-III HER2-positive BC received the dHER2 immunotherapeutic after surgical resection and adjuvant therapy. They were allocated into four cohorts receiving different doses of dHER2 (20, 100, 500 µg) combined with a fixed AS15 dose. Safety and immunogenicity (dHER2-specific antibody responses) were assessed. After completing the immunization schedule (three or six doses over 14 weeks) and a six-month follow-up, the patients were followed for 5 years for late toxicity, long-term immunogenicity, and clinical status. The immunizations were well tolerated, and increasing doses of dHER2 had no impact on the frequency or severity of adverse events. Few late toxicities were reported, and after 5 years 45/54 patients (83.3 %) were still alive, while 28/45 (62 %) with known disease status were disease free. Regarding the immunogenicity of the compound, a positive association was found between the dHER2 dose, the immunization schedule, and the prevalence of dHER2-specific humoral responses. Among the patients receiving the most intense immunization schedule with the highest dHER2 dose, 6/8 maintained their dHER2-specific antibody response 5 years after immunization. The dHER2 immunotherapeutic had an acceptable safety profile in early HER2-positive BC patients. dHER2-specific antibody responses were induced, with the rate of responders increasing with the dHER2 dose and the number and frequency of immunizations.

PGC-1ß regulates HER2-overexpressing breast cancer cells proliferation by metabolic and redox pathways.

Breast cancer is a prevalent neoplastic disease among women worldwide which treatments still present several side effects and resistance. Considering that cancer cells present derangements in their energetic homeostasis, and that peroxisome proliferator-activated receptor- gamma coactivator 1 (PGC-1) is crucial for cellular metabolism and redox signaling, the main objective of this study was to investigate whether there is a relationship between PGC-1 expression, the proliferation of breast cancer cells and the mechanisms involved. We initially assessed PGC-1ß expression in complementary DNA (cDNA) from breast tumor of patients bearing luminal A, luminal B, and HER2-overexpressed and triple negative tumors. Our data showed that PGC-1ß expression is increased in patients bearing HER2-overexpressing tumors as compared to others subtypes. Using quantitative PCR and immunoblotting, we showed that breast cancer cells with HER2-amplification (SKBR-3) have greater expression of PGC-1ß as compared to a non-tumorous breast cell (MCF-10A) and higher proliferation rate. PGC-1ß expression was knocked down with short interfering RNA in HER2-overexpressing cells, and cells decreased proliferation. In these PGC-1ß-inhibited cells, we found increased citrate synthase activity and no marked changes in mitochondrial respiration. Glycolytic pathway was decreased, characterized by lower intracellular lactate levels. In addition, after PGC-1ß knockdown, SKBR-3 cells showed increased reactive oxygen species production, no changes in antioxidant activity, and decreased expression of ERRα, a modulator of metabolism. In conclusion, we show an association of HER2-overexpression and PGC-1ß. PGC-1ß knockdown impairs HER2-overexpressing cells proliferation acting on ERRα signaling, metabolism, and redox balance.

Neural Stem Cells Secreting Anti-HER2 Antibody Improve Survival in a Preclinical Model of HER2 Overexpressing Breast Cancer Brain Metastases.

The treatment of human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer has been revolutionized by trastuzumab. However, longer survival of these patients now predisposes them to forming HER2 positive brain metastases, as the therapeutic antibodies cannot cross the blood brain barrier. The current oncologic repertoire does not offer a rational, nontoxic targeted therapy for brain metastases. In this study, we used an established human neural stem cell line, HB1.F3 NSCs and generated a stable pool of cells secreting a high amount of functional full-length anti-HER2 antibody, equivalent to trastuzumab. Anti-HER2Ab secreted by the NSCs (HER2Ab-NSCs) specifically binds to HER2 overexpressing human breast cancer cells and inhibits PI3K-Akt signaling. This translates to HER2Ab-NSC inhibition of breast cancer cell growth in vitro. Preclinical in vivo experiments using HER2Ab overexpressing NSCs in a breast cancer brain metastases (BCBM) mouse model demonstrate that intracranial injection of HER2Ab-NSCs significantly improves survival. In effect, these NSCs provide tumor localized production of HER2Ab, minimizing any potential off-target side effects. Our results establish HER2Ab-NSCs as a novel, nontoxic, and rational therapeutic approach for the successful treatment of HER2 overexpressing BCBM, which now warrants further preclinical and clinical investigation.

Human epidermal growth receptor-2 overexpressing early operable primary breast cancers in older (≥70 years) women: biology and clinical outcome in comparison with younger (<70 years) patients.

INTRODUCTION: There is dearth of literature reporting the prevalence and biological characteristics as well as the long-term clinical outcome of human epidermal growth factor receptor-2 (HER2) overexpressing tumours in older women. Currently, research involving trastuzumab at large focuses on the younger population. This study aimed to analyse their biological characteristics and to compare them with their younger counterparts from a single centre with a long-term clinical follow-up. METHODS: Over 37 years (1973-2010), 1758 older (≥70 years) women with early operable (<5 cm) primary breast cancer were managed in a dedicated clinic and have complete clinical information available. Of these, 813 patients underwent primary surgery and 575 had good quality tumour samples available for tissue microarray analysis using indirect immunohistochemistry. Comparison was made with data from a well-characterised younger (<70 years) series (N = 1711) treated between 1986 and 1998 (before adjuvant trastuzumab became standard) in our institution. Forty five (7.6%) and 140 (8.2%) patients from the older and younger series, respectively, had HER2-positive tumours. RESULTS: HER2 overexpression was seen in 45 (7.6%) older women and 140 (8.2%) in younger patients (P = 0.56). HER2 overexpressing tumours in older women when compared with that in their younger counterparts were associated with low Ki67 and high bcl2 expression (P < 0.05). Only 26% of the younger patients and none of the older patients received adjuvant chemotherapy, and no patients at the time received trastuzumab. However, there was no significant difference in the outcome of the two age groups (5-year breast cancer-specific survival rate: <70 years = 65% versus >70 years = 70%, P = 0.51). CONCLUSION: HER2 overexpressing tumours in older women showed relatively a less aggressive phenotype and did not show any inferior long-term clinical outcome despite not having received chemotherapy when compared with the younger patients. The precise role of different adjuvant systemic therapies in this population needs to be delineated.

Deep learning-assisted monitoring of trastuzumab efficacy in HER2-Overexpressing breast cancer via SERS immunoassays of tumor-derived urinary exosomal biomarkers.

Monitoring drug efficacy is significant in the current concept of companion diagnostics in metastatic breast cancer. Trastuzumab, a drug targeting human epidermal growth factor receptor 2 (HER2), is an effective treatment for metastatic breast cancer. However, some patients develop resistance to this therapy; therefore, monitoring its efficacy is essential. Here, we describe a deep learning-assisted monitoring of trastuzumab efficacy based on a surface-enhanced Raman spectroscopy (SERS) immunoassay against HER2-overexpressing mouse urinary exosomes. Individual Raman reporters bearing the desired SERS tag and exosome capture substrate were prepared for the SERS immunoassay; SERS tag signals were collected to prepare deep learning training data. Using this deep learning algorithm, various complicated mixtures of SERS tags were successfully quantified and classified. Exosomal antigen levels of five types of cell-derived exosomes were determined using SERS-deep learning analysis and compared with those obtained via quantitative reverse transcription polymerase chain reaction and western blot analysis. Finally, drug efficacy was monitored via SERS-deep learning analysis using urinary exosomes from trastuzumab-treated mice. Use of this monitoring system should allow proactive responses to any treatment-resistant issues.

Dual-Targeted Therapy in HER2-Overexpressing Breast Cancer with Trastuzumab and Novel Cholesterol-Based Nioplexes Silencing Mcl-1.

The challenge in HER2-overexpressing breast cancer therapy lies in creating an effective target therapy to overcome treatment resistance. Monoclonal antibodies and target gene silencing by siRNA are two potential strategies that have been widely developed for treating HER2-positive breast cancer. The siRNA delivery system is a crucial factor that influences siRNA therapy's success. In this study, lipid-based nanoparticles (cationic niosomes) composed of different cholesterol-based cationic lipids were formulated and characterized for delivering siRNA into HER2-overexpressing breast cancer cells. Niosomes containing a trimethylammonium headgroup showed the highest siRNA delivery efficiency with low toxicity. The myeloid cell leukemia-1 (Mcl-1) siRNA nioplex treatment significantly decreased mRNA expression and breast cancer cell growth. Dual-targeted therapy, consisting of treatment with an Mcl-1 siRNA nioplex and trastuzumab (TZ) solution, noticeably promoted cell-growth inhibition and apoptosis. The synergistic effect of dual therapy was also demonstrated by computer modeling software (CompuSyn version 1.0). These findings suggest that the developed cationic niosomes were effective nanocarriers for siRNA delivery in breast cancer cells. Furthermore, the Mcl-1 nioplex/TZ dual treatment establishes a synergistic outcome that may have the potential to treat HER2-overexpressing breast cancer.

Inhibitory Effect of Lentivirus-Mediated Gag-Caspase-8 on the Growth of HER-2 Overexpressing Primary Human Breast Cancer Cells.

Background: Apoptosis plays an essential role in the development and treatment of tumors, and caspase-8 (CASP8) plays an important role in the enzyme cascade reaction that leads to apoptosis. Human epidermal growth factor receptor 2 (HER-2) overexpressing breast cancer is highly aggressive and has a high recurrence rate and poor prognosis. This study investigated whether lentivirus-mediated Gag-CASP8 can effectively deliver activated CASP8 into primary human breast cancer cells overexpressing HER-2 to induce apoptosis and explore the underlying mechanism. Materials and Methods: HER-2 overexpressing primary human breast cancer cells were infected with lentivirus-like particles carrying Gag-CASP8. Results: After a 48h infection of primary human breast cancer cells with HER-2 by lentivirus-mediated Gag-CASP8, significant differences were observed in the survival rate, migration ability, S-phase number of cells, apoptosis rate, and intracellular activated CASP8 and caspase-3 levels in tumor cells compared with those in the control group (p < 0.05). Conclusions: Lentivirus-mediated Gag-CASP8 can deliver activated CASP8 into HER-2 overexpressing primary human breast cancer cells and induce apoptosis by activating caspase-3, a downstream apoptotic executive molecule. By blocking the S-phase to inhibit cell proliferation and migration, lentivirus-mediated Gag-CASP8 provides a reference for tumor gene therapy.

Evaluation of the antimetastatic and anticancer activities of morin in HER2­overexpressing breast cancer SK­BR­3 cells.

Morin (2',3,4',5,7­pentahydroxyflavone), a flavonoid isolated from members of the Moraceae family and the leaves of Cudranaia tricuspidata Buread, is a well­known natural substance with anti­inflammatory, antioxidative, antimetastasis, and anticancer effects. However, its anticancer activity has not been comprehensively investigated in human epidermal growth factor receptor 2 (HER2)­overexpressing breast cancer cells. Here, we evaluated the effects of morin on metastasis and cell viability in HER­2­overexpressing human breast cancer SK­BR­3 cells. Our results revealed that morin (150­200 µM) prevented endothelial growth factor (EGF)­induced metastatic potential and suppressed cell migration and MMP­9 activity by inhibiting the EGFR signaling pathway in SK­BR­3 cells by gelatin zymography, wound healing assay and western blotting. Interestingly, morin­induced reductions in cell viability were found to be associated with inhibition of the HER2/EGFR signaling pathway by sulforhodamine B assay and western blotting. Morin also induced the phosphorylation of H2A.X and downregulated the expression levels of RAD51 and survivin, which implied morin­induced DNA damage and that this damage accumulated in HER­2­overexpressing SK­BR­3 cells. Western blot analysis and fluorescent immunocytochemisty showed that morin also activated autophagy after 24 h of treatment and this was maintained at 48 h when activation of apoptosis via PARP cleavage resulted in the activation of caspase­3 and ­7, which was associated with the release of cytochrome c to the cytosol from mitochondria. In addition, the phosphorylation of p38 and JNK was enhanced in the HER­2­overexpressing SK­BR­3 cells by morin after 24 and 48 h of treatment, which suggested p38 and JNK participate in morin­induced cell death. Taken together, the present investigation indicates that morin is a powerful therapeutic candidate for the treatment of HER2­overexpressing breast cancer because it suppresses the EGFR signaling pathway, induces cell death by inhibiting the HER2/EGFR signaling pathway, and suppresses metastatic potential.

Arctigenin-mediated cell death of SK-BR-3 cells is caused by HER2 inhibition and autophagy-linked apoptosis.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) is well-known as the therapeutic marker in breast cancer. Therefore, we evaluated anti-cancer activity of arctigenin (ATG) on in SK-BR-3 HER2-overexpressing human breast cancer cells. METHODS: Cell viability and cytotoxicity were analyzed with MTT and colony-forming assay and cell cycle analysis was performed by flow cytometry. The expression and/or phosphorylation of proteins in whole cell lysate and mitochondrial fraction were analyzed by Western blotting. Cellular levels of LC3 and sequestosome 1 (SQSTM1/P62) were observed by immunofluorescence analysis. RESULTS: The result showed that ATG decreased cell viability of SK-BR-3 cells in a concentration-dependent manner. Moreover, ATG increased the sub G1 population linked to the suppression of HER2/EGFR1 signaling pathway. Furthermore, ATG increased the phosphorylation of H2AX and down-regulated RAD51 and survivin expressions, indicating that ATG induced DNA damage and inhibited the DNA repair system. We also found that cleavages of caspase-7 and PARP by releasing mitochondrial cytochrome c into the cytoplasm were induced by ATG treatment for 72 h through the reduction of Bcl-2 and Bcl-xL levels in mitochondria. In contrast, the levels of LC-3 and SQSTM1/P62 were increased by ATG for 24 h through the Akt/mTOR and AMPK signaling pathway. CONCLUSIONS: Taken together, this study indicates that autophagy-linked apoptosis is responsible for the anti-cancer activity of ATG in SK-BR-3 cells, and suggests that ATG is considered a potential therapeutic for the treatment of HER2-overexpressing breast cancer.

Efficacy and safety of a novel anti-HER2 therapeutic antibody RC48 in patients with HER2-overexpressing, locally advanced or metastatic gastric or gastroesophageal junction cancer: a single-arm phase II study.

BACKGROUND: Current treatment options for human epidermal growth factor receptor 2 (HER2)-overexpressing gastric cancer at third-line have shown limited clinical benefit. Further, there is no specific treatment for HER2 immunohistochemistry (IHC) 2+ and fluorescence in-situ hybridization-negative patients. Here, we report the efficacy and safety of a novel anti-HER2 antibody RC48 for patients with HER2-overexpressing, advanced gastric or gastroesophageal junction cancer. METHODS: Patients with HER2-overexpressing (IHC 2+ or 3+), locally advanced or metastatic gastric or gastroesophageal junction cancer who were under at least second-line therapy were eligible and received RC48 2.5 mg/kg alone every 2 weeks. The primary endpoint was the objective response rate (ORR) assessed by an independent review committee. Secondary endpoints included progression-free survival (PFS), overall survival (OS), duration of response, time to progression, disease control rate, and safety. RESULTS: Of 179 patients screened, 125 were eligible and received RC48 treatment. The ORR was 24.8% (95% confidence interval [CI]: 17.5%-33.3%). The median PFS and OS were 4.1 months (95% CI: 3.7-4.9 months) and 7.9 months (95% CI: 6.7-9.9 months), respectively. The most frequently reported adverse events were decreased white blood cell count (53.6%), asthenia (53.6%), hair loss (53.6%), decreased neutrophil count (52.0%), anemia (49.6%), and increased aspartate aminotransferase level (43.2%). Serious adverse events (SAEs) occurred in 45 (36.0%) patients, and RC48-related SAEs were mainly decreased neutrophil count (3.2%). Seven patients had adverse events that led to death were not RC48-related. CONCLUSIONS: RC48 showed promising activity with manageable safety, suggesting potential application in patients with HER2-overexpressing, advanced gastric or gastroesophageal junction cancer who have previously received at least two lines of chemotherapy.

Bioengineering bacterial encapsulin nanocompartments as targeted drug delivery system.

The development of Drug Delivery Systems (DDS) has led to increasingly efficient therapies for the treatment and detection of various diseases. DDS use a range of nanoscale delivery platforms produced from polymeric of inorganic materials, such as micelles, and metal and polymeric nanoparticles, but their variant chemical composition make alterations to their size, shape, or structures inherently complex. Genetically encoded protein nanocages are highly promising DDS candidates because of their modular composition, ease of recombinant production in a range of hosts, control over assembly and loading of cargo molecules and biodegradability. One example of naturally occurring nanocompartments are encapsulins, recently discovered bacterial organelles that have been shown to be reprogrammable as nanobioreactors and vaccine candidates. Here we report the design and application of a targeted DDS platform based on the Thermotoga maritima encapsulin reprogrammed to display an antibody mimic protein called Designed Ankyrin repeat protein (DARPin) on the outer surface and to encapsulate a cytotoxic payload. The DARPin9.29 chosen in this study specifically binds to human epidermal growth factor receptor 2 (HER2) on breast cancer cells, as demonstrated in an in vitro cell culture model. The encapsulin-based DDS is assembled in one step in vivo by co-expressing the encapsulin-DARPin9.29 fusion protein with an engineered flavin-binding protein mini-singlet oxygen generator (MiniSOG), from a single plasmid in Escherichia coli. Purified encapsulin-DARPin_miniSOG nanocompartments bind specifically to HER2 positive breast cancer cells and trigger apoptosis, indicating that the system is functional and specific. The DDS is modular and has the potential to form the basis of a multi-receptor targeted system by utilising the DARPin screening libraries, allowing use of new DARPins of known specificities, and through the proven flexibility of the encapsulin cargo loading mechanism, allowing selection of cargo proteins of choice.

Recent Use of Oral Contraceptives and Risk of Luminal B, Triple-Negative, and HER2-Overexpressing Breast Cancer.

Oral contraceptive use is a well-established risk factor for breast cancer and is common among reproductive-aged women in the USA. Its relationship with less common, more aggressive, molecular subtypes is less clear. A population-based case-case analysis was conducted comparing three less common molecular subtypes to luminal A breast cancer among 1701 premenopausal cases aged 21-49 diagnosed with a first primary invasive breast cancer between 2004 and 2015. Medical record reviews and structured interviewer-administered questionnaires were used to collect data on oral contraceptive use. Multinomial logistic regression was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (95% CI) for recency of oral contraceptive use for each subtype of breast cancer. Current use of oral contraceptives and use within 5 years before diagnosis was associated with lower odds of H2E tumors compared with luminal A tumors [OR = 0.5, 95% CI: 0.3, 0.9 and OR = 0.5, 95% CI: 0.4, 0.8, respectively] with increasing duration associated with decreasing odds (p for trend < 0.05). Oral contraceptive use was not associated with risks of TN or luminal B breast cancer. Oral contraceptive use may be more strongly positively associated with risks of luminal A, luminal B, and TN breast cancer than with risk of H2E tumors. These findings contribute to the etiological understanding of different molecular subtypes of breast cancer.