Breast Tumors In Mice Research Articles

Correlation of micro vessel density and c- Myc expression in breast tumor of mice following mesenchymal stem cell therapy

Stem cell therapy for degenerative diseases has been established; however there are controversies over the treatment of solid tumors with stem cell transplantation. In the present study, the anti-tumor action of mesenchymal stem cells (MSCs) has been examined in a mouse model of breast cancer with emphasize on tumor growth, angiogenesis and c-Myc expression in breast tumors. For this purpose, MSCs were isolated from bone marrow of Balb/c mice and characterized. A Balb/c mouse model of breast cancer was developed and subjected to cell therapy intra venous (I.V) or intra tumor (I.T) with MSCs. Tumor growth was measured using a digital caliber for until the end of experiment (30days). Then the mice were sacrificed and their tumors were removed and processed for histopathological examination, immunohistochemical assay of CD31 and measuring of c-Myc expression using quantitative PCR. Detection of the labeled-MSCs in tumors following injection of the cells (I.V or I.T) clearly showed the homing of MSCs into tumors. Tumor growth in case of MSC-treated mice by I.V and I.T routes was inhibited by approximately 28% and 34% respectively compared to controls. The suppression of angiogenesis was reflected in Micro Vessel Density (MVD) following I.V or I.T delivery of the MSCs. c-Myc gene expression in tumor tissues of mice treated I.V or IT with MSCs was down-regulated to 28.0% and 16.0% respectively compare to control groups. In conclusion, growth inhibition of breast tumors in mice due to MSC therapy is associated with modulation of c-Myc activation and angiogenesis markers.

Anti-Tumor Responses By Ibrutinib and Anti-PD-1 Blockade Is Enhanced By Phosphatidylserine-Targeting Antibody Therapy

Introduction: Phosphatidylserine (PS) is a phospholipid normally residing in the inner leaflet of the plasma membrane that becomes exposed on vascular endothelial cells and tumor cells in the tumor microenvironment, particularly in response to chemotherapy and irradiation. Binding of antibodies targeting PS on the tumor endothelial cells and tumors induces the recruitment of immune cells and engages the immune system to destroy tumor and associated vasculature and by blocking the immunosuppressive action of PS. Recent studies have demonstrated that PS-targeting antibodies enhance the anti-tumor activity of immune checkpoint antibody blockade to CTLA-4 and PD-1 in mouse breast and melanoma tumor models (Freimark et al. Cancer Immunol. Res. 2016; Gray et al. Breast Cancer Res 2016). Ibrutinib is an approved anticancer drug targeting B-cell malignancies that is a selective, covalent inhibitor of the enzyme Bruton's tyrosine kinase(BTK) in B-cell tumors. Data from recent mouse tumor studies demonstrate that ibrutinib in combination with anti-PD-1 antibody blockade inhibits growth of solid tumors (lacking BTK expression) suggesting that ibrutinib may inhibit kinases of the immune system such as interleukin-2 inducible T-cell kinase (ITK), to enhance specific anti-tumor responses (Sagiv-Barfli et al. PNAS 20 2015).Methods: The present study was conducted to evaluate the anti-tumor effects of combination therapy including PS-targeting antibody mouse chimeric 1N11 (mch1N11), ibrutinib (32765) and anti-PD-1 antibody using C57BL/6 mice bearing triple negative E0771 breast tumors. Tumors were staged to an initial volume of ~100mm3and randomized to treatment groups (N=10) with mch1N11 or isotype at 10 mg/kg qw, anti-PD-1 at 2.5 mg/kg qw or ibrunitib 6 mg/kg or vehicle qd x 8. Tumor volumes were measured twice per week to determine tumor growth inhibition (TGI) relative to control treated animals until a maximum volume of 1500-2000mm3. The in vitro sensitivity of E0771 tumor cells to ibrutinib was compared to drug sensitive Jeko-1 lymphoma cells in a 72 hour growth and viability assay.Results: The E0771 cell line is resistant in vitroto 10 mM ibrutinib compared to the drug-sensitive Jeko-1 cell line (Figure 1). Mice bearing E0771 tumors treated with mch1N11, ibrutinib and anti-PD-1 alone had 22.2%, 23.5% and 32.6% TGI respectively. Combination of two agents increased the TGI for mch1N11 and ibrutinib to 30.5%, ibrutinib and anti-PD-1 to 34.5%, mch1N11 and anti-PD-1 to 36.1%. A triple combination therapy had statistically greater TGI compared to control treated mice (59.9%, p = 0.0084) and was greater than single and double combination therapies.Conclusion:Treatment of solid tumors with a combination of inhibitors that target PS, ITK and the PD-1/PD-L1 axis in the tumor microenvironment provides a novel treatment for solid tumors, including triple negative breast cancer. [Display omitted] [Display omitted] DisclosuresGong:Peregrine Pharmaceuticals, Inc.: Employment. Gray:Peregrine Pharmaceuticals, Inc.: Employment. Hutchins:Peregrine Pharmaceuticals, Inc.: Employment. Freimark:Peregrine Pharmaceuticals, Inc.: Employment.

Calcitriol stimulates gene expression of cathelicidin antimicrobial peptide in breast cancer cells with different phenotype.

BackgroundIn normal and neoplastic cells, growth-promoting, proangiogenic, cytotoxic and pro-apoptotic effects have all been attributed to cathelicidin antimicrobial peptide (CAMP). Nevertheless, little is known about the factors regulating this peptide expression in breast cancer. Herein we asked if the well-known antineoplastic hormone calcitriol could differentially modulate CAMP gene expression in human breast cancer cells depending on the cell phenotype in terms of efficacy and potency.MethodsThe established breast cancer cell lines MCF7, BT-474, HCC1806, HCC1937, SUM-229PE and a primary cell culture generated from invasive ductal breast carcinoma were used in this study. Calcitriol regulation of cathelicidin gene expression in vitro and in human breast cancer xenografts was studied by real time PCR. Tumorigenicity was evaluated for each cell line in athymic mice.ResultsEstrogen receptor (ER)α + breast cancer cells showed the highest basal CAMP gene expression. When incubated with calcitriol, CAMP gene expression was stimulated in a dose-dependent and cell phenotype-independent manner. Efficacy of calcitriol was lower in ERα + cells when compared to ERα- cells (<10 vs. >70 folds over control, respectively). Conversely, calcitriol lowest potency upon CAMP gene expression was observed in the ERα-/EGFR+ SUM-229PE cell line (EC50 = 70.8 nM), while the highest was in the basal-type/triple-negative cells HCC1806 (EC50 = 2.13 nM) followed by ERα + cells MCF7 and BT-474 (EC50 = 4.42 nM and 14.6 nM, respectively). In vivo, lower basal CAMP gene expression was related to increased tumorigenicity and lack of ERα expression. Xenografted triple-negative breast tumors of calcitriol-treated mice showed increased CAMP gene expression compared to vehicle-treated animals.ConclusionsIndependently of the cell phenotype, calcitriol provoked a concentration-dependent stimulation on CAMP gene expression, showing greater potency in the triple negative HCC1806 cell line. Efficacy of calcitriol was lower in ERα + cells when compared to ERα- cells in terms of stimulating CAMP gene expression. Lower basal CAMP and lack of ERα gene expression was related to increased tumorigenicity. Our results suggest that calcitriol anti-cancer therapy is more likely to induce higher levels of CAMP in ERα- breast cancer cells, when compared to ERα + breast cancer cells.

Anti-tumor activity of SL4 against breast cancer cells: induction of G2/M arrest through modulation of the MAPK-dependent p21 signaling pathway.

SL4, a chalcone-based compound, has been shown to retard tumor invasion and angiogenesis by suppressing HIF1 activity and to induce apoptosis by promoting ROS release. Here, we report that SL4 is able to inhibit the proliferation of different types of breast cancer cell in vitro and in vivo by inducing G2/M cell cycle arrest. Our results showed that SL4 exhibited strong anti-proliferative activity in several human breast cancer cell lines, with IC50 values lower than 1.3 μM. Further studies indicated that SL4 induced G2/M arrest in these cell lines. Mechanistically, SL4 reduces the expression of cyclin A2 and cdc25C and decreases the activity of the cdc2/cyclin B1 complex. Notably, SL4 treatment resulted in an obvious increase in p21 mRNA and protein levels through activation of MAPK signaling pathways, but not the TGF-β pathway. SP600125 and PD98059, specific inhibitors of JNK kinase and ERK kinase, significantly blocked the SL4-induced G2/M phase arrest and upregulation of p21. Furthermore, SL4 suppressed the growth of established breast tumors in nude mice through upregulation of p21 and downregulation of cdc25C, and displayed a good safety profile. Taken together, these findings demonstrate the potential value of SL4 as a novel multi-target anti-tumor drug candidate.

Deficiency of X-Linked Protein Kinase Nrk during Pregnancy Triggers Breast Tumor in Mice

The onset and/or growth of breast tumor are controlled, at least in part, by estrogen. Therefore, to prevent the development of breast tumor, estrogen-dependent proliferation of mammary epithelial cells during pregnancy needs to be suppressed once the mammary gland is fully developed to enable lactation. However, the underlying molecular mechanisms remain unknown. Nrk is an X-linked protein serine/threonine kinase in the germinal center kinase family. Herein, we demonstrate a frequent occurrence of breast tumors in homozygous and heterozygous Nrk mutant mice that have experienced pregnancy/parturition. The tumors never developed in the mutant mice without a history of pregnancy/parturition. They exhibited histopathological features of noninvasive tubular adenocarcinoma, and expressed estrogen receptor α. At late gestation when estrogen receptor α expression was significantly reduced in the wild-type mammary gland, grossly normal mammary glands in the pregnant Nrk mutant mice occasionally contained hyperplastic foci continuously expressing the receptor. Consistently, Nrk expression was induced in the wild-type mammary gland at this period of pregnancy. On the other hand, the pregnant Nrk mutant mice also showed elevated blood estrogen levels at late gestation. We suggest that Nrk suppresses the excessive proliferation of mammary epithelial cells during pregnancy, and the impairment of this regulatory system leads to frequent occurrence of breast tumor in Nrk mutant mice.

Bioresponsive and fluorescent hyaluronic acid-iodixanol nanogels for targeted X-ray computed tomography imaging and chemotherapy of breast tumors

Nanotheranostics is a rapidly growing field combining disease diagnosis and therapy, which ultimately may add in the development of ‘personalized medicine’. Here, we designed and developed bioresponsive and fluorescent hyaluronic acid-iodixanol nanogels (HAI-NGs) for targeted X-ray computed tomography (CT) imaging and chemotherapy of MCF-7 human breast tumors. HAI-NGs were obtained with a small size of ca. 90nm, bright green fluoresence and high serum stability from hyaluronic acid-cystamine-tetrazole and reductively degradable polyiodixanol-methacrylate via nanoprecipitation and a photo-click crosslinking reaction. Notably, paclitaxel (PTX)-loaded HAI-NGs showed a fast glutathione-responsive drug release. Confocal microscopy displayed efficient uptake of HAI-NGs by CD44 overexpressing MCF-7 cells via a receptor-mediated mechanism. MTT assays revealed that HAI-NGs were nontoxic to MCF-7 cells even at a high concentration of 1mg/mL whereas PTX-loaded HAI-NGs exhibited strong inhibition of MCF-7 cells. The in vivo pharmcokinetics, near-infrared imaging and biodistribution studies revealed that HAI-NGs significantly prolonged the blood circulation time and enhanced tumor accumulation of PTX. Interestingly, significantly enhanced CT imaging was observed for MCF-7 breast tumors in nude mice via either intratumoral or intravenous injection of HAI-NGs as compared to iodixanol. HAI-NGs fluoresence was distributed thoughout the whole tumor indicating deep tumor penetration. PTX-loaded HAI-NGs showed effective suppression of tumor growth with little systemic toxicity. HAI-NGs appear as a “smart” theranostic nanoplatform for the treatment of CD44 positive tumors.

The effects of low-level laser irradiation on breast tumor in mice and the expression of Let-7a, miR-155, miR-21, miR125, and miR376b.

Low-level laser therapy (LLLT) is a form of photon therapy which can be a non-invasive therapeutic procedure in cancer therapy using low-intensity light in the range of 450-800nm. One of the main functional features of laser therapy is the photobiostimulation effects of low-level lasers on various biological systems including altering DNA synthesis and modifying gene expression, and stopping cellular proliferation. This study investigated the effects of LLLT on mice mammary tumor and the expression of Let-7a, miR155, miR21, miR125, and miR376b in the plasma and tumor samples. Sixteen mice were equally divided into four groups including control, and blue, green, and red lasers at wavelengths of 405, 532, and 632nm, respectively. Weber Medical Applied Laser irradiation was carried out with a low power of 1-3mW and a series of 10 treatments at three times a week after tumor establishment. Tumor volume was weekly measured by a digital vernier caliper, and qRT-PCR assays were performed to accomplish the study. Depending on the number of groups and the p value of the Kolmogorov-Smirnov test of normality, a t test, a one-way ANOVA, or a non-parametric test was used for data analyses, and p < 0.05 was considered to be statistically significant. The average tumor volume was significantly less in the treated blue group than the control group on at days 21, 28, and 35 after cancerous cell injection. Our data also showed an increase of Let-7a and miR125a expression and a decrease of miR155, miR21, and miR376b expression after LLLT with the blue laser both the plasma and tumor samples compared to other groups. It seems that the non-invasive nature of laser bio-stimulation can make LLLT an attractive alternative therapeutic tool.

Redox-Sensitive and Intrinsically Fluorescent Photoclick Hyaluronic Acid Nanogels for Traceable and Targeted Delivery of Cytochrome c to Breast Tumor in Mice.

In spite of their high specificity and potency, few protein therapeutics are applied in clinical cancer therapy owing to a lack of safe and efficacious delivery systems. Here, we report that redox-sensitive and intrinsically fluorescent photoclick hyaluronic acid nanogels (HA-NGs) show highly efficient loading and breast tumor-targeted delivery of cytochrome c (CC). HA-NGs were obtained from hyaluronic acid-graft-oligo(ethylene glycol)-tetrazole (HA-OEG-Tet) via inverse nanoprecipitation and catalyst-free photoclick cross-linking with l-cystine dimethacrylamide (MA-Cys-MA). HA-NGs exhibited a superb CC loading content of up to 40.6 wt %, intrinsic fluorescence (λem = 510 nm), and a small size of ca. 170 nm. Notably, CC-loaded nanogels (CC-NGs) showed a fast glutathione-responsive protein release behavior. Importantly, released CC maintained its bioactivity. MTT assays revealed that CC-NGs were highly potent with a low IC50 of 3.07 μM to CD44+ MCF-7 human breast tumor cells. Confocal microscopy observed efficient and selective internalization of fluorescent HA-NGs into MCF-7 cells. Interestingly, HA-NGs exhibited also effective breast tumor penetration. The therapeutic results demonstrated that CC-NGs effectively inhibited the growth of MCF-7 breast tumor xenografts at a particularly low dose of 80 or 160 nmol CC equiv./kg. Moreover, CC-NGs did not cause any change in mice body weight, corroborating their low systemic side effects. Redox-sensitive and intrinsically fluorescent photoclick hyaluronic acid nanogels have appeared as a "smart" protein delivery nanoplatform enabling safe, efficacious, traceable, and targeted cancer protein therapy in vivo.

M2-polarized and tumor-associated macrophages alter NK cell phenotype and function in a contact-dependent manner

The crosstalk between NK cells and M1 macrophages has a vital role in the protection against infections and tumor development. However, macrophages in the tumor resemble an M2 phenotype, and, at present, their effect on NK cells is less clear. This study investigated whether tumor-associated macrophages (TAMs) have a role in altering NK cell function and phenotype using in vitro cocultures of murine NK cells with peritoneal or bone marrow-derived, M2-polarized macrophages or TAMs isolated from spontaneous mouse breast tumors. We report here that both peritoneal and bone marrow-derived M2 macrophages, as well as TAMs, substantially inhibit NK cell activation and concordant cytotoxicity against tumor cells. The mechanism for this inhibition was found to require contact between the respective cell types. Both M2 macrophages and TAMs are producers of the immunosuppressive cytokine TGF-β. The inhibition of TGF-β restored the cytotoxicity of NK cells in contact with M2 macrophages, implicating TGF-β in the mechanism for NK cell inhibition. In addition to affecting NK cell function, TAMs also induced a CD27lowCD11bhigh-exhausted NK cell phenotype, which corresponds with the reduced activation and cytotoxicity observed. This study reveals a novel implication of TAMs in the tumor-associated inhibition of NK cell function by demonstrating their capacity to directly alter NK cell cytotoxicity and phenotype in a contact-dependent mechanism involving TGF-β. These findings identify the interaction between NK cells and TAMs as a prospective therapeutic target to enhance NK cell effector function for effective NK cell cancer therapies.

Abstract 724: MicroRNA-100/mTOR/IL-1ra signaling maintains TAMs phenotype and enhances tumor cell stemness property in mouse breast cancer

Abstract Tumor-associated macrophages(TAMs),the main part of immune cells in tumor microenvironment(TME),play a potent role in promoting tumorigenesis. MicroRNAs (miRs) are considered to be crucial regulators in tumor progression. However, the role that miRs play in TAMs phenotype regulation still remains unclear. In this study, we demonstrated that miR-100 played an important role in maintaining TAMs phenotype and enhancing tumor stemness properties. First, miRNome of TAMs isolated from mouse breast tumor was performed. Compared with macrophages from normal spleen, 40 miRs candidates, in 150 TAMs-high and 169 TAMs-low expressed miRs which were selected from miRNome, were further identified by real-time PCR. Importantly, miR-100 was found with TAMs-high expression pattern(about 70 folds changes). Moreover, we found that miR-100 overexpressed RAW264.7 cells and peritoneal macrophages gained M2 phenotype such as CD206+ cells percentage. Mechanism study demonstrated that miR-100 up-regulated IL-1ra expression detected by cytokine array. Furthermore we found that IL-1ra could enhance 4T1 breast cancer cell stemness properties including increasing tumor cell sphere formation and drug resistance in vitro. Taken together, our results demonstrate that TAMs-high expressed miR-100 could function to maintain the phenotype of TAMs via targeting mTOR pathway, and promote tumorigenesis by enhancing IL-1ra secretion, which would also serve as a promising therapy target to remodel TME and tumor metastasis. Citation Format: Wei Wang, Yan Liu, Jian Guo, Huiwen He, Junling Xie, Chong Chen, Yunping Luo. MicroRNA-100/mTOR/IL-1ra signaling maintains TAMs phenotype and enhances tumor cell stemness property in mouse breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 724.

Abstract 4194: Assessment of novel benzosuberene-based vascular disrupting agents (VDA) on diverse tumor lines

Abstract Introduction: In developing any new drug, non-invasive assays of efficacy provide vital insight into activity with respect to dosing and pharmacodynamics of action. We have previously demonstrated the utility of dynamic bioluminescence imaging (dBLI) to evaluate VDA activity [1,2]. The current study, which evaluated the vascular-disrupting activity upon treatment with the promising novel benzosuberene-based agents KGP18 and KGP265 [structurally inspired by the natural product, combretastatin A-4 (CA4)] led to significantly decreased and delayed light emission indicative of vascular disruption. Methods: Human breast cancer cells (MDA-MB-231), prostate cancer cells (PC3), and lung cancer cells (A549) along with mouse breast tumor 4T1 cells were implanted in male SCID/Balb/c mice. The dose of KGP265 ranged from 5 to 15 mg/kg and the well studied VDA combretastatin A-4P (CA4P; 120 mg/kg) was used as positive control. Dynamic BLI was performed at baseline, 4, 24, 48 and 72 hours after IP administration of each VDA. Fresh D-luciferin was administered at each time point. As a control, additional tumor bearing mice were injected with the same volume of saline. Results: Dose escalation indicated that higher doses produced more effective vascular shutdown, and doses of 3 mg/kg KGP18 and 7.5 mg/kg KGP265 appeared optimal, being effective while causing little observable toxicity with the MBA-MD-231 tumor model. The optimal dose of KGP265 was 5 mg/kg for 4T1, and 10 mg/kg for A549 and PC3. Treatment of the 4T1, PC3 and A549 tumors with the above dose of KGP265 greatly reduced signal output in BLI images. By 4 hours, about 90% of signal was reduced and the signal stayed down for the next 48 hours post-injection. In vivo observations were confirmed by post mortem histology. Treatment with KGP265 led to significantly decreased and delayed light emission indicative of vascular disruption in different tumor types. The BLI signal was reduced by 90% at 4 hours compared to baseline. Light emission remained significantly depressed up to 48 hours and 72 hours, whereas CA4P showed substantial recovery by 24 hours and further recovery by 48 hours. Meanwhile light emission was highly consistent following administration of saline as control with reproducible kinetics and intensities. Conclusion: The results indicate that KGP18 and KGP265 cause significant vascular disruption. KGP265 is a phosphorylated prodrug of KGP18; it has enhanced water solubility, and maintains substantial vascular disrupting efficacy. Compared to CA4P (optimal dose 120 mg/kg), the new VDAs are effective at lower doses and achieve similar imaging results, suggesting enhanced efficacy. We are continuing to explore efficacy and therapeutic response through combination studies. Acknowledgment: CA4P was kindly provided by Dr. David Chaplin of OXiGENE. Supported by NIH R01CA140674

Abstract 3806: Phosphaplatins are potent inducers of pigment epithelial- derived factor (PEDF)

Abstract Pigment Epithelial Derived Factor (PEDF) is a secreted glycoprotein that exhibits several biological activities, most notably as a potent anti-angiogenic agent as well as a neurotrophic factor. As such, this molecule has potential application as therapeutics for cancer and a variety of neurological diseases. However, prior art methods directed towards enhancing and stabilizing PEDF expression in vivo have met with little success. Therefore, methods that could lead to the stable expression of PEDF in vivo are still needed. We have recently shown that PEDF protein is overexpressed in tumor cells treated with platinum based drugs; phosphaplatins that are platinum-(II) and platinum-(IV) complexes coordinated to a pyrophosphate moiety. The objective of this study is to extend our previous findings by measuring PEDF expression in both malignant cells and normal neuronal tissues after treating them with these compounds. We also investigated the impact of PEDF upregulation on important biological processes such as apoptosis, proliferation and invasion of tumor cells. Our data showed that there was a significant upregulation (over 4-fold) of PEDF in brain of mice treated with phosphoplatins when compared to the control animals. The compounds were found to stimulate PEDF expression in cultured neuronal cells when assessed in vitro (P&amp;lt;0.05 vs. untreated control groups). In tumor cells, phosphoplatins upregulated PEDF expression in a dose-dependent manner in various tumor cell lines. In one particular mouse breast tumor cell line (4T1), the data showed that phosphaplatin doses in the range of 25 to 100 μM stimulated the expression of PEDF at 12 and 24 hrs, which declined thereafter. Remarkably, a subsequent treatment of the tumor cells with phosphaplatins at 24 hrs prevented the decline of PEDF expression, suggesting a direct correlation between phosphaplatins and PEDF overexpression. The upregulation of PEDF in the tumor cells was paralleled by increased apoptosis and decreased cell proliferation and invasion. In summary, phosphaplatins mediated overexpression of PEDF in vivo suggests a potential neuroprotective effect of these compounds. While in tumors, phosphaplatins may exhibit antitumor activity via multiple effects, including anti-angiogenesis, enhanced apoptosis, and decreased proliferation and invasion, predominately through stimulating overexpression of PEDF. Citation Format: Louiza Belkacemi, Armando Rivera, Lu Yang, Rathindra N. Bose, Shaun X. Zhang. Phosphaplatins are potent inducers of pigment epithelial- derived factor (PEDF). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3806.

Serotonin transporter antagonists target tumor-initiating cells in a transgenic mouse model of breast cancer.

Accumulating data suggests that the initiation and progression of human breast tumors is fueled by a rare subpopulation of tumor cells, termed breast tumor-initiating cells (BTIC), which resist radiotherapy and chemotherapy. Consequently, therapies that abrogate BTIC activity are needed to achieve durable cures for breast cancer patients. To identify such therapies we used a sensitive assay to complete a high-throughput screen of small molecules, including approved drugs, with BTIC-rich mouse mammary tumor cell populations. We found that inhibitors of the serotonin reuptake transporter (SERT) and serotonin receptors, which include approved drugs used to treat mood disorders, were potent inhibitors of mouse BTIC activity as determined by functional sphere-forming assays and the initiation of tumor formation by transplant of drug-exposed tumor cells into syngeneic mice. Moreover, sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), synergized with docetaxel (Taxotere) to shrink mouse breast tumors in vivo. Hence drugs targeting the serotonergic system might be repurposed to treat breast cancer patients to afford more durable breast cancer remissions.

Delphinidin-3-glucoside suppresses breast carcinogenesis by inactivating the Akt/HOTAIR signaling pathway.

BackgroundThe long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) plays a crucial role in cancer progression, which is regulated by the interferon regulatory factor-1 (IRF1) and up-streaming Akt activation. The present study evaluated the chemopreventive effects of delphinidin-3-glucoside (Dp), a major anthocyanin present in pigmented fruits and vegetables, on breast carcinogenesis, and investigate the role of the Akt/HOTAIR signaling pathway.MethodsHuman breast epithelial cells MCF10A were treated with carcinogens (NNK and B[a]P) or co-treated with carcinogens plus Dp for 30 days. Then, the cancer-associated properties of the treated cells were evaluated to assess the carcinogenesis and the effects of Dp. HOTAIR levels were detected by qRT-PCR. The proteins expression was measured by western blots, immunofluorescence and immunohistochemistry. Xenografted tumors were made by implanting breast cancer cells MDA-MB-231-Luc-GFP in athymic mice. ChIP-qPCR analysis was used to detect the IRF1 binding to the HOTAIR promoter.ResultsCarcinogens treatment induces apparent carcinogenic transformation in MCF10A cells including reduced dependence on growth factors, anchorage-independent cell growth and aberrant wound-healing ability, which is effectively suppressed by Dp co-treatment. The level of HOTAIR significantly increases in a time-dependent manner during chronic breast carcinogenesis. Dp treatment down-regulates HOTAIR expression in breast carcinogenesis and breast cancer cells. Furthermore, Dp administration inhibits the growth of xenografted breast tumors in athymic mice, and decreases HOTAIR in vivo. Further studies showed that Dp represses Akt activation, promotes IRF1 expression and increases IRF1 binding to the HOTAIR promoter. Silence of IRF1 expression via transfecting cells with IRF1 siRNAs significantly reduced the effects of Dp on HOTAIR, resulting in decreased cytotoxic effects of Dp on breast cancer cells.ConclusionsThese data suggest the effective chemopreventive effect of Dp on breast carcinogenesis, in which down-regulation of HOTAIR plays a critical role.

Intravital microscopy for evaluating tumor perfusion of nanoparticles exposed to non-invasive radiofrequency electric fields.

Poor biodistribution and accumulation of chemotherapeutics in tumors due to limitations on diffusive transport and high intra-tumoral pressures (Jain RK, Nat Med. 7(9):987–989, 2001) have prompted the investigation of adjunctive therapies to improve treatment outcomes. Hyperthermia has been widely applied in attempts to meet this need, but it is limited in its ability to reach tumors in deeply located body regions. High-intensity radiofrequency (RF) electric fields have the potential to overcome such barriers enhancing delivery and extravasation of chemotherapeutics. However, due to factors, including tumor heterogeneity and lack of kinetic information, there is insufficient understanding of time-resolved interaction between RF fields and tumor vasculature, drug molecules and nanoparticle (NP) vectors. Intravital microscopy (IVM) provides time-resolved high-definition images of specific tumor microenvironments, overcoming heterogeneity issues, and can be integrated with a portable RF device to enable detailed observation over time of the effects of the RF field on kinetics and biodistribution at the microvascular level. Herein, we provide a protocol describing the safe integration of IVM with a high-powered non-invasive RF field applied to 4T1 orthotopic breast tumors in live mice. Results show increased perfusion of NPs in microvasculature upon RF hyperthermia treatment and increased perfusion, release and spreading of injected reagents preferentially in irregular vessels during RF exposure.Electronic supplementary materialThe online version of this article (doi:10.1186/s12645-016-0016-7) contains supplementary material, which is available to authorized users.

The Action of Discoidin Domain Receptor 2 in Basal Tumor Cells and Stromal Cancer-Associated Fibroblasts Is Critical for Breast Cancer Metastasis.

High levels of collagen deposition in human and mouse breast tumors are associated with poor outcome due to increased local invasion and distant metastases. Using a genetic approach, we show that, in mice, the action of the fibrillar collagen receptor discoidin domain receptor 2 (DDR2) in both tumor and tumor-stromal cells is critical for breast cancer metastasis yet does not affect primary tumor growth. In tumor cells, DDR2 in basal epithelial cells regulates the collective invasion of tumor organoids. In stromal cancer-associated fibroblasts (CAFs), DDR2 is critical for extracellular matrix production and the organization of collagen fibers. The action of DDR2 in CAFs also enhances tumor cell collective invasion through a pathway distinct from the tumor-cell-intrinsic function of DDR2. This work identifies DDR2 as a potential therapeutic target that controls breast cancer metastases through its action in both tumor cells and tumor-stromal cells at the primary tumor site.

The influence of miR-34a expression on stemness and cytotoxic susceptibility of breast cancer stem cells

ABSTRACTIn this study, we investigate the effect of miR-34a expression and biological characteristics of breast cancer stem cells (BCSCs). The mammospheres were formed from murine breast cancer cell line 4T1 and regarded as murine BCSCs. Identification of stemness molecules and cloning experiments validate the biological characteristics of BCSCs we have established. We showed that miR-34a, as a tumor suppressor, could separately reduce the stemness of BCSCs and activate the cytotoxic susceptibility of BCSCs to natural killer (NK) cells in vitro via down regulating the expression of Notch1 signaling molecules. Moreover, miR-34a could completely restrain established mice breast tumor xenografts in vivo in the NOD/SCID mice that have functional NK cells at a normal level, whereas it was less effective in NOD/SCID/ CD122/IL-2Rβ mice that do not have functional NK cells. We conclude that miR-34a is a crucial, dual tumor suppressor and BCSCs-targeting immunotherapeutic agent and has shown efficacy in the treatment of murine breast cancer. The results also suggest that impaired NK cells could contribute to the resistance to therapies.

Hyaluronidase Embedded in Nanocarrier PEG Shell for Enhanced Tumor Penetration and Highly Efficient Antitumor Efficacy.

One of the major challenges in applying nanomedicines to cancer therapy is their low interstitial diffusion in solid tumors. Although the modification of nanocarrier surfaces with enzymes that degrade extracellular matrix is a promising strategy to improve nanocarrier diffusion in tumors, it remains challenging to apply this strategy in vivo via systemic administration of nanocarriers due to biological barriers, such as reduced blood circulation time of enzyme-modified nanocarriers, loss of enzyme function in vivo, and life-threatening side effects. Here, we report the conjugation of recombinant human hyaluronidase PH20 (rHuPH20), which degrades hyaluronic acid, on the surfaces of poly(lactic-co-glycolic acid)-b-polyethylene glycol (PLGA-PEG) nanoparticles followed by anchoring a relatively low density layer of PEG, which reduces the exposure of rHuPH20 for circumventing rHuPH20-mediated clearance. Despite the extremely short serum half-life of rHuPH20, our unique design maintains the function of rHuPH20 and avoids its effect on shortening nanocarrier blood circulation. We also show that rHuPH20 conjugated on nanoparticles is more efficient than free rHuPH20 in facilitating nanoparticle diffusion. The facile surface modification quadruples the accumulation of conventional PLGA-PEG nanoparticles in 4T1 syngeneic mouse breast tumors and enable their uniform tumor distribution. The rHuPH20-modified nanoparticles encapsulating doxorubicin efficiently inhibit the growth of aggressive 4T1 tumors under a low drug dose. Thus, our platform technology may be valuable to enhance the clinical efficacy of a broad range of drug nanocarriers. This study also provides a general strategy to modify nanoparticles with enzymes that otherwise may reduce nanoparticle circulation or lose function in the blood.

Upregulated Expression of GRP78 Supports ER Stress‐induced Apoptosis in Tunicamycin Treated Triple Negative Breast Tumor

Breast cancer affects nearly 1.5 million women (5–10%) worldwide per year. Triple negative breast cancer (TNBC) accounts for 15% of all breast cancer with a disproportionate share of mortality. The patients are younger and pre‐menopausal. The cancers are poorly differentiated, and most fall into the basal subgroup of breast cancers. The long‐term survival is extremely low because specific treatment guidelines are lacking. The patients are managed with standard treatment causing a high rate of local and systemic relapse. This make them resistant to existing targeted therapies (endocrine/biologics/adjuvant/neo‐adjuvant). Anthracycline/taxane combination therapy and PARP inhibitor are currently being explored but not known if they would achieve a pathological complete response (pCR). Protein glycosylation has been claimed as a universal feature of helping cancer cells escaping immune surveillance, facilitate tumor invasion, and increase malignancy with increased tumor burden and poor prognosis as well as enhanced angiogenesis. Based on the glycomics profile of human breast cancer cells as well as tumor specimen, we have hypothesized that targeting asparagine‐linked (N‐linked) protein glycosylation would evolve a new generation therapeutic preventing breast tumor progression and eliminating the disease. To test our hypothesis, we have used tunicamycin a natural product that competitively inhibits the N‐acetyl glucosaminyl 1‐phosphate transferase activity in the ER and consequently the N‐linked protein glycosylation. When tested in a triple negative breast tumor in nude mice, the tumor progression is inhibited by ~65% in one week at tunicamycin concentration of 0.25 mg/Kg administered orally twice a week. Human triple negative breast cancer cells (MDA‐MB‐231) are also equally susceptible to tunicamycin action. The cells are arrested in G1 and exhibit ER stress followed by induction of apoptosis mediated by unfolded protein response (upr) signaling. Western blotting and qRT‐PCR support increased expression of the ER stress master regulator GRP78. But, the immunofluorescence microscopy could not detect GRP78 on the surface of control or tunicamycin treated cells. The result is the same in cells cultured in the absence of serum. GRP78 fluorescence however, is detectable in cells after either they are fixed with ice‐cold methanol or permeabilized with digitonin. We, therefore, conclude that GRP78 is not expressed on the outer‐leaflet of the cell surface of the triple negative human breast cancer cells MDA‐MB‐231. But, its intracellular expression is anti‐tumorigenic.Support or Funding InformationSupported in part by NIH U54‐CA096297 and Komen for the Cure BCTR06582 (DKB) and NIH/NIMHD 2G12MD007583 (KB).

Cleavage of Type I Collagen by Fibroblast Activation Protein-α Enhances Class A Scavenger Receptor Mediated Macrophage Adhesion.

Pathophysiological conditions such as fibrosis, inflammation, and tumor progression are associated with modification of the extracellular matrix (ECM). These modifications create ligands that differentially interact with cells to promote responses that drive pathological processes. Within the tumor stroma, fibroblasts are activated and increase the expression of type I collagen. In addition, activated fibroblasts specifically express fibroblast activation protein-α (FAP), a post-prolyl peptidase. Although FAP reportedly cleaves type I collagen and contributes to tumor progression, the specific pathophysiologic role of FAP is not clear. In this study, the possibility that FAP-mediated cleavage of type I collagen modulates macrophage interaction with collagen was examined using macrophage adhesion assays. Our results demonstrate that FAP selectively cleaves type I collagen resulting in increased macrophage adhesion. Increased macrophage adhesion to FAP-cleaved collagen was not affected by inhibiting integrin-mediated interactions, but was abolished in macrophages lacking the class A scavenger receptor (SR-A/CD204). Further, SR-A expressing macrophages localize with activated fibroblasts in breast tumors of MMTV-PyMT mice. Together, these results demonstrate that FAP-cleaved collagen is a substrate for SR-A-dependent macrophage adhesion, and suggest that by modifying the ECM, FAP plays a novel role in mediating communication between activated fibroblasts and macrophages.