Dexamethasone inhibits the proliferation of tumor cells

Objective

Dexamethasone (DEX) is a glucocorticoid that is commonly used in clinics. Previously, DEX has been shown to inhibit the function of immune system; however, DEX is often used to treat side reactions, such as nausea and vomiting caused by chemotherapy in clinics. Therefore, it is necessary to study the role of DEX in the treatment of cancer.

Methods

The effects of DEX on HepG2 were studied in vitro by Cell Counting Kit-8 method, cell cycle, and scratch test. The transplanted tumor model of HepG2 was established in nude mice to study the anti-tumor effect of DEX in vivo. In addition, in order to study the effect of DEX on the immune system, we also established a transplanted tumor model of 4T1 in normal immunized mice to study treatment effect and mechanism of DEX in mice of normal immune function.

Results

The results showed that DEX inhibited the proliferation of HepG2 in vitro and in vivo, affecting the cycle and migration of HepG2 cells, and the expression of c-Myc and the activation of mTOR signaling pathway were inhibited. The expression of key enzymes related to glucose metabolism is altered, especially that of phosphoenolpyruvate carboxykinase2 (PCK2). In normal immunized mice, DEX also inhibits the proliferation of tumor cells 4T1, while the proportion of CD4+CD45+T cells and CD8+CD45+ T cells in CD45+ cells in the lymph nodes upregulated, the proportion of Treg cells in CD4+ T cells downregulated in lymph nodes, and the proportion of MDSCs in tumor tissues downregulated.

Conclusion

DEX can inhibit tumor cells in vitro and in vivo. The mechanism is to inhibit the activation of mTOR signaling pathway by inhibiting the expression of c-Myc, further affecting the expression of key enzymes involved in glucose metabolism, especially PCK2. In addition, DEX has an inhibitory effect on the immune system, which may be the reason why DEX still has anti-tumor effect in normal mice.

A non-toxic approach for treatment of breast cancer and its metastases: capecitabine enhanced photodynamic therapy in a murine breast tumor model

AIM

Breast cancer (BCA) in women is a leading cause of mortality and morbidity; distant metastases occur in ~40% of cases. Here, as an alternative to ionizing radiation therapy and chemotherapy and their associated side effects, we explored a new combination approach using capecitabine (CPBN) and aminolevulinate-based photodynamic therapy (PDT). We had previously developed a combination PDT approach in which 5-fluorouracil (5FU), a differentiation-promoting agent, increases the levels of protoporphyrin IX (PpIX) in cancer cells when given as a neoadjuvant prior to aminolevulinic acid (ALA). However, 5FU can be toxic when administered systemically at high levels. We reasoned that CPBN, a known chemotherapeutic for BCA and less toxic than 5FU (because CPBN is metabolized to 5FU specifically within tumor tissues), might work equally well as a PDT neoadjuvant.

METHODS

Murine 4T1 BCA cells harboring a luciferase transgene were injected into breast fat pads of female nude mice. CPBN (600 mg/kg/day) was administered by oral gavage for 3 days followed by intraperitoneal ALA administration and PDT with red light (633 nm) on day 4. Tumor growth and regression were monitored in vivo using bioluminescence imaging. Histological changes in primary tumors and metastases were assessed by immunohistochemistry after necropsy.

RESULTS

CPBN pretreatment of 4T1 tumors increased cellular differentiation, reduced proliferation, raised PpIX levels, enhanced tumor cell death, and reduced metastatic spread of 4T1 cells post-PDT, relative to vehicle-only controls.

CONCLUSION

The use of CPBN as a non-toxic PDT neoadjuvant for treatment of BCA represents a novel approach with significant potential for translation into the clinic.

Using an in-vivo syngeneic spontaneous metastasis model identifies ID2 as a promoter of breast cancer colonisation in the brain

Background

Dissemination of breast cancers to the brain is associated with poor patient outcome and limited therapeutic options. In this study we sought to identify novel regulators of brain metastasis by profiling mouse mammary carcinoma cells spontaneously metastasising from the primary tumour in an immunocompetent syngeneic host.

Methods

4T1 mouse mammary carcinoma sublines derived from primary tumours and spontaneous brain and lung metastases in BALB/c mice were subject to genome-wide expression profiling. Two differentially expressed genes, Id2 and Aldh3a1, were validated in in-vivo models using mouse and human cancer cell lines. Clinical relevance was investigated in datasets of breast cancer patients with regards to distant metastasis-free survival and brain metastasis relapse-free survival. The role of bone morphogenetic protein (BMP)7 in regulating Id2 expression and promoting cell survival was investigated in two-dimensional and three-dimensional in-vitro assays.

Results

In the spontaneous metastasis model, expression of Id2 and Aldh3a1 was significantly higher in 4T1 brain-derived sublines compared with sublines from lung metastases or primary tumour. Downregulation of expression impairs the ability of cells to colonise the brain parenchyma whereas ectopic expression in 4T1 and human MDA-MB-231 cells promotes dissemination to the brain following intracardiac inoculation but has no impact on the efficiency of lung colonisation. Both genes are highly expressed in oestrogen receptor (ER)-negative breast cancers and, within this poor prognosis sub-group, increased expression correlates with reduced distant metastasis-free survival. ID2 expression also associates with reduced brain metastasis relapse-free survival. Mechanistically, BMP7, which is present at significantly higher levels in brain tissue compared with the lungs, upregulates ID2 expression and, after BMP7 withdrawal, this elevated expression is retained. Finally, we demonstrate that either ectopic expression of ID2 or BMP7-induced ID2 expression protects tumour cells from anoikis.

Conclusions

This study identifies ID2 as a key regulator of breast cancer metastasis to the brain. Our data support a model in which breast cancer cells that have disseminated to the brain upregulate ID2 expression in response to astrocyte-secreted BMP7 and this serves to support metastatic expansion. Moreover, elevated ID2 expression identifies breast cancer patients at increased risk of developing metastatic relapse in the brain.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-1093-9) contains supplementary material, which is available to authorized users.

Sub-10 nm Cu5FeS4 cube for magnetic resonance imaging-guided photothermal therapy of cancer

BACKGROUND

Facile synthesis and small size theranostic agents have shown great potential for cancer diagnosis and treatment.

PURPOSE

A ternary compound (Cu5FeS4), Fe doped copper sulfide, with novel magnetic properties and strong near-infrared absorption was prepared for magnetic resonance imaging (MRI) imaging guided photothermal therapy of cancer.

PATIENTS AND METHODS

Firstly, the capability of magnetic resonance imaging based on the novel magnetic properties and the photothermal performance due to the strong near-infrared absorption was investigated in vitro. Then, the magnetic resonance imaging guided photothermal therapy for 4T1 tumor-bearing mouse was carried out.

RESULTS

The Cu5FeS4 cube with good T1-weighted MRI, excellent photothermal performance and low cytotoxicity has been investigated. More importantly, the T1-weighted MRI for 4T1 tumor-bearing mouse will get the best contrast effect at tumor site after 8 h of intravenous injection of Cu5FeS4 cube. Under the guidance of the T1-weighted MRI, the PTT was carried out at 8 h after intravenous injection of Cu5FeS4 cube and only the group combined intravenous administration of Cu5FeS4 cube and laser irradiation nearly cured the tumor after 14 days.

CONCLUSION

Our study not only provides a new material for personalized treatment of tumors, but also further promotes potential applications of the cancer theranostic agents.

In Vitro and In Vivo Efficacy of the Monocarboxylate Transporter 1 Inhibitor AR-C155858 in the Murine 4T1 Breast Cancer Tumor Model

Monocarboxylate transporter 1 (MCT1), also known as a L-lactate transporter, is a potential therapeutic target in cancer. The objectives of this study were to evaluate efficacy and assess concentration-effect relationships of AR-C155858 (a selective and potent MCT1 inhibitor) in murine 4T1 breast cancer cells and in the 4T1 tumor xenograft model. Western blotting of 4T1 cells demonstrated triple negative breast cancer (TNBC) characteristics and overexpression of MCT1 and CD147 (a MCT1 accessory protein), but absence of MCT4 expression. AR-C155858 inhibited the cellular L-lactate uptake and cellular proliferation at low nanomolar potencies (IC₅₀ values of 25.0 ± 4.2 and 20.2 ± 0.2 nM, respectively). In the xenograft 4T1 mouse model of immunocompetent animals, AR-C155858 (10 mg/kg i.p. once daily) had no effect on tumor volume and weight. Treatment with AR-C155858 resulted in slightly increased tumor lactate concentrations; however, the changes were not statistically significant. AR-C155858 was well tolerated, as demonstrated by the unchanged body weight and blood lactate concentrations. Average blood and tumor AR-C155858 concentrations (110 ± 22 and 574 ± 245 nM, respectively), 24 h after the last dose, were well above the IC₅₀ values. These data indicate that AR-C155858 penetrated 4T1 xenograft tumors and was present at high concentrations but was ineffective in decreasing tumor growth. Evaluations of AR-C155858 in other preclinical models of breast cancer are needed to further assess its efficacy.

Synthetic cannabinoids nano-micelles for the management of triple negative breast cancer

Triple-negative breast cancer (TNBC) is a highly heterogeneous disease with poor prognosis and inadequate therapeutic outcome. This contribution reports the use of a cannabinoid derivative, WIN55,212-2 (WIN) on the growth of TNBC in a 4T1 syngeneic mouse model. To reduce the well-known psychoactive side effects of cannabinoids, we prepared a nanomicellar formulation of WIN (SMA-WIN). In vivo biodistribution, in silico ADME predictions, anticancer activity, and psychoactive effect of WIN and SMA-WIN studies suggest that SMA-WIN formulation can reduce to greater extent tumor growth with milder psychoactive side effects when compared to free drug. Finally, the effects of WIN and SMA-WIN in combination with doxorubicin (Doxo), an established chemotherapeutic agent for the treatment of TNBC, were investigated in vitro and in vivo. SMA-WIN in combination with Doxo showed therapeutic efficacy and was able to reduce the tumor volume of TNBC murine model drastically. Moreover, SMA-WIN, while favoring drug tumor accumulation, minimized the adverse psychoactive effects that have impeded the use of this agent in the clinic. To our knowledge, this is the first report for the assessment of cannabinoid nanoparticles in vivo for the treatment of TNBC and its enhanced anticancer effect at low doses with Doxo. These findings suggest a new therapeutic strategy in the management of TNBC.

Two-photon fluorescence lifetime imaging of intrinsic NADH in three-dimensional tumor models

Most studies using intrinsic NAD(P)H as biomarkers for energy metabolism and mitochondrial anomalies have been conducted in routine two-dimensional (2D) cell culture formats. Cellular metabolism and cell behavior, however, can be significantly different in 2D cultures from that in vivo. As a result, there are emerging interests in integrating noninvasive, quantitative imaging techniques of NAD(P)H with in vivo-like three-dimensional (3D) models. The overall features and metabolic responses of the murine breast cancer cells line 4T1 in 2D cultures were compared with those in 3D collagen matrix using integrated optical micro-spectroscopy. The metabolic responses to two novel compounds, MD1 and TPPBr, that target metabolism by disrupting monocarboxylate transporters or oxidative phosphorylation (OXPHOS), respectively, were investigated using two-photon fluorescence lifetime imaging microscopy (2P-FLIM) of intracellular NAD(P)H in 2D and 3D cultures. 4T1 cells exhibit distinct behaviors in a collagenous 3D matrix from those in 2D culture, forming anastomosing multicellular networks and spherical acini in 3D culture, as opposed to simple flattened epithelial plaques in 2D culture. The cellular NAD(P)H in 3D collagen matrix exhibits a longer fluorescence lifetime as compared with 2D culture, which is attributed to an enhanced population of enzyme-bound NAD(P)H in the 3D culture. TPPBr induces mitochondrial hyperpolarization in 2D culture of 4T1 cells along with an enhanced free NAD(P)H population, which suggest an interference with OXPHOS. In contrast, 2P-FLIM of cellular NAD(P)H revealed an enhanced autofluorescence lifetime in 3D 4T1 cultures after MD1 treatment as compared with MD1-treated 2D culture and the control 3D culture. Physical and chemical microenvironmental signaling are critical factors in understanding how therapeutic compounds target cancer cells by disrupting their metabolic pathways. Integrating 2P-FLIM of intrinsic NAD(P)H with refined 3D tumor-matrix in vitro models promises to advance our understanding of the roles of metabolism and metabolic plasticity in tumor growth and metastatic behavior. © 2018 International Society for Advancement of Cytometry.

AS1411 aptamer-targeted gold nanoclusters effect on the enhancement of radiation therapy efficacy in breast tumor-bearing mice

AIM

Herein, the AS1411 aptamer-targeted ultrasmall gold nanoclusters (GNCs) were assessed at different aspects as a radiosensitizer.

MATERIALS & METHODS

AS1411 aptamer-conjugated gold nanoclusters (Apt-GNCs) efficacy was evaluated at cancer cells targeting, radiosensitizing effect, tumor targeting, and biocompatibility in breast tumor-bearing mice.

RESULTS

Flow cytometry and fluorescence microscopy exhibited more cellular uptake for Apt-GNCs in comparison with GNCs. In addition, inductively coupled plasma optical emission spectrometry results demonstrated its effective tumor targeting as the tumors' gold content for GNCs and Apt-GNCs were 8.53 and 15.33 μg/g, respectively. Apt-GNCs significantly enhanced radiotherapy efficacy as mean tumors' volume decreased about 39% and 9 days increase in the mice survival was observed. Both GNCs and Apt-GNCs were biocompatible.

CONCLUSION

The Apt-GNCs is a novel and efficient  radiosensitizer.

Yulangsan polysaccharide inhibits 4T1 breast cancer cell proliferation and induces apoptosis in vitro and in vivo

Yulangsan polysaccharide (YLSPS) is derived from the root of Millettia pulchra (Benth.) Kurz var. Recent studies have postulated YLSPS as a regimen for cancer treatment. However, the underlying mechanism anti-breast cancer is still poorly unknown. The aim of this study was to examine the suppressive and apoptosis effect of YLSPS on the growth of breast cancer cell 4T1 and its possible underlying mechanism. In this study, breast cancer cell 4T1 viability and apoptosis were assessed by CCK-8 and flow cytometry, relative quantitative real-time PCR and western blot after treated with drug-serum of YLSPS. Furthermore, therapy experiments were conducted using a Balb/c mouse transplanted tumor model of breast cancer. The number of apoptotic cells and microvascular density (MVD) in the tumor tissues were assessed by TUNEL and CD34 immunostaining. Immunohistochemical assays and ELISA were used to detect the expression of VEGF, Bcl-2, Bax and Caspase-3 in the tissues. The in vitro studies showed that the drug-serum of YLSPS significantly inhibition of proliferation and effectively induced apoptosis of 4T1 cells. Oral administration of YLSPS in the breast cancer models significantly reduced the tumor volume and weight. The enhanced antitumor efficacy was associated with decreased angiogenesis, an enhanced antioxidant capacity, an increased induction of apoptosis and an inhibition of lung metastasis. These findings indicate that YLSPS significantly inhibited mouse breast cancer growth in vitro and in vivo. These data suggest that YLSPS may serve as a potential therapeutic agent for breast cancer.

Comparison of [18F]Fluorocholine and [18F]Fluordesoxyglucose for assessment of progression, lung metastasis detection and therapy response in murine 4T1 breast tumor model

The [18F]Fluorocholine ([18F]FCH) tracer for PET imaging has been proven to be effective for several malignances. However, there are only a few studies related to its breast tumor applicability and they are still limited. The aim of this study was investigate the efficacy of [18F]FCH/PET compared to [18F]FDG/PET in a murine 4T1 mammary carcinoma model treated and nontreated. [18F]FCH/PET showed its applicability for primary tumor and lung metastasis detection and their use for response monitoring of breast cancer therapeutics at earlier stages.

Potential anti-proliferative activity of AgNPs synthesized using M. longifolia in 4T1 cell line through ROS generation and cell membrane damage

To overcome the problem of breast cancer, silver nanoparticles (AgNPs) synthesized using Indian medicinal plant Madhuca longifolia could be explored as an alternative anticancer medicine. Synthesized AgNPs were studied their characteristics and their anti-proliferative property was investigated in breast cancer cell line (4T1). Based on zeta sizer analysis, the size of the AgNPs was 103.5 nm and potential -9.57 eV. Fe-SEM results showed particle size of 69.4-99.4 nm while TEM images indicated the particle size of 18-24 nm. In dose-dependent study, AgNPs showed 93% of anti-proliferative activity at 50 μg/ml whereas the methanolic extract of M. longifolia showed 80% activity only at 10-fold increased concentration (500 μg/ml). AgNPs exhibited higher level of cytotoxicity in breast cancer cell line than extract through cell wall degradation and ROS generation. Such effective AgNPs could be investigated further through in vivo models with a view to develop anticancer drug.

The Multifaceted Role of STAT3 in Mammary Gland Involution and Breast Cancer

Since seminal descriptions of signal transducer and activator of transcription 3 (STAT3) as a signal transducer and transcriptional regulator, which is most usually activated by phosphorylation of a specific tyrosine residue, a staggering wealth of research has delineated the key role of this transcription factor as a mediator of mammary gland postlactational regression (involution), and paradoxically, a pro-survival factor in breast cancer and some breast cancer cell lines. STAT3 is a critical regulator of lysosomal-mediated programmed cell death (LM-PCD) during mammary gland involution, where uptake of milk fat globules, and consequent high levels of free fatty acids, cause permeabilisation of lysosomal vesicle membranes, in turn leading to cathepsin protease leakage and cell death. A recent proteomic screen of STAT3-induced changes in lysosomal membrane protein components has highlighted wide-ranging effects of STAT3, which may coordinate LM-PCD via the stimulation of endocytosis, intracellular trafficking, and lysosome biogenesis. In parallel, STAT3 regulates the acute phase response during the first phase of involution, and it contributes to shaping the pro-tumourigenic 'wound healing' signature of the gland during the second phase of this process. STAT3 activation during involution is important across species, although some differences exist in the progression of involution in dairy cows. In breast cancer, a number of upstream regulators can lead to STAT3 activation and the effects of phosphorylation of STAT3 are equally wide-ranging. Recent studies have implicated microRNAs in some regulatory pathways. In this review, we will examine the multifaceted role of STAT3 in mammary gland involution and tumourigenesis, incorporating a review of these fundamental processes in tandem with a discussion of recent developments in this field.

Sialic Acid Metabolism: A Key Player in Breast Cancer Metastasis Revealed by Metabolomics

Metastatic breast cancer is currently incurable. It has recently emerged that different metabolic pathways support metastatic breast cancer. To further uncover metabolic pathways enabling breast cancer metastasis, we investigated metabolic differences in mouse tumors of differing metastatic propensities using mass spectrometry-based metabolomics. We found that sialic acid metabolism is upregulated in highly metastatic breast tumors. Knocking out a key gene in sialic acid metabolism, Cmas, inhibits synthesis of the activated form of sialic acid, cytidine monophosphate-sialic acid and decreases the formation of lung metastases in vivo. Thus, the sialic acid pathway may be a new target against metastatic breast cancer.

pH Responsive Polymer Micelles Enhances Inhibitory Efficacy on Metastasis of Murine Breast Cancer Cells

A pH sensitive micellar cargo was fabricated for pH triggered delivery of hydrophobic drug paclitaxel with pH controlled drug release profiles. The size, drug loading content, and encapsulation efficiency of PTX loaded micelles were 20-30 nm, 7.5%, 82.5%, respectively. PTX loaded PELA-PBAE micelles could enhance the intracellular uptake of a model drug significantly, with increased cytotoxicity and inhibition of tumor metastasis on 4T1 cells, as confirmed by wound healing assay and tumor cells invasion assay. The expression of metastasis and apoptosis correlated proteins on 4T1 cells decreased remarkably after intervention by PTX loaded polymer micelles, as demonstrated by western blotting and quantitative reverse transcriptional-polymerase chain reaction (qRT-PCR). Our results demonstrated the pH responsive polymer micelles might have the potential to be used in the treatment of metastatic breast tumors.

Alterations in NO- and PGI2- dependent function in aorta in the orthotopic murine model of metastatic 4T1 breast cancer: relationship with pulmonary endothelial dysfunction and systemic inflammation

Background

Patients with cancer develop endothelial dysfunction and subsequently display a higher risk of cardiovascular events. The aim of the present work was to examine changes in nitric oxide (NO)- and prostacyclin (PGI₂)-dependent endothelial function in the systemic conduit artery (aorta), in relation to the formation of lung metastases and to local and systemic inflammation in a murine orthotopic model of metastatic breast cancer.

Methods

BALB/c female mice were orthotopically inoculated with 4T1 breast cancer cells. Development of lung metastases, lung inflammation, changes in blood count, systemic inflammatory response (e.g. SAA, SAP and IL-6), as well as changes in NO- and PGI₂-dependent endothelial function in the aorta, were examined 2, 4, 5 and 6 weeks following cancer cell transplantation.

Results

As early as 2 weeks following transplantation of breast cancer cells, in the early metastatic stage, lungs displayed histopathological signs of inflammation, NO production was impaired and nitrosylhemoglobin concentration in plasma was decreased. After 4 to 6 weeks, along with metastatic development, progressive leukocytosis and systemic inflammation (as seen through increased SAA, SAP, haptoglobin and IL-6 plasma concentrations) were observed. Six weeks following cancer cell inoculation, but not earlier, endothelial dysfunction in aorta was detected; this involved a decrease in basal NO production and a decrease in NO-dependent vasodilatation, that was associated with a compensatory increase in cyclooxygenase-2 (COX-2)- derived PGI₂ production.

Conclusions

In 4 T1 metastatic breast cancer in mice early pulmonary metastasis was correlated with lung inflammation, with an early decrease in pulmonary as well as systemic NO availability. Late metastasis was associated with robust, cancer-related, systemic inflammation and impairment of NO-dependent endothelial function in the aorta that was associated with compensatory upregulation of the COX-2-derived PGI₂ pathway.

Coordinated responses to individual tumor antigens by IgG antibody and CD8+ T cells following cancer vaccination

Background

One of today’s greatest hurdles for cancer immunotherapy is the absence of information regarding which tumor antigens are already recognized by patients receiving immunotherapies, and whether those therapies then boost or generate an immune response against tumor proteins. For CD8+ T cells in particular, patient-specific immune recognition and responses at the level of individual tumor antigens are rarely characterized. Because of this, some immunologists have turned to serum antibodies as an alternative measure of antigen-specific anti-tumor immunity. In this work, we sought to simultaneously interrogate serum IgG and CD8+ T cell recognition of individual tumor antigens to determine whether antigen-specific serum IgG antibodies provide a window into the behavior of antigen-specific CD8+ T cell responses. Using antibody-based assays to evaluate immune response repertoires and focus T cell antigen exploration could afford substantial advantages for discovering and monitoring the anti-cancer immune responses of patients enrolled on clinical trials.

Methods

We vaccinated female BALB/c mice with a novel combination of an autophagosome-enriched vaccine derived from 4T1 mammary carcinoma along with poly-I:C adjuvant, then screened serum for IgG binding to arrays of 15mer peptides containing known mutation sites in 4T1. Simultaneously, we primed CD8+ T cell cultures from these same animals with 8-11mer peptides derived from these antigens. These primed T cells were then stimulated to measure recognition of the peptides or live 4T1 cells by IFNγ release.

Results

Vaccinated animals demonstrate increases in antigen-specific CD8+ T cell recognition of 4T1 tumor cells and peptides. For proteins confirmed in 4T1 cells and vaccine by mass spectrometry, there is a correlation between this increased CD8+ T cell IFNγ release and serum IgG binding to individual peptide antigens.

Conclusions

These results suggest it is possible to observe some features of a patient’s antigen-specific T cell repertoire via an antibody surrogate, which has implications for tumor antigen discovery and clinical monitoring of antigen-specific anti-tumor immunity.

Electronic supplementary material

The online version of this article (10.1186/s40425-018-0331-0) contains supplementary material, which is available to authorized users.

Mechanical ventilation promotes lung metastasis in experimental 4T1 breast cancer lung-metastasized models

BACKGROUND/PURPOSE

The aim of this study was to test the hypothesis that mechanical ventilation (MV) during cancer surgery induces lung stroma/tissue milieu changes, creating a favorable microenvironment for postoperative lung metastatic tumor establishment.

MATERIALS AND METHODS

In Protocol A, female BALB/c mice were divided into an MV group and a control (no MV) group, both of which were anesthetized and subjected to intravenous injection of green fluorescent protein (GFP)-labeled mouse mammary carcinoma cell line (4T1) cells. After 24 h, the lung tissue was removed and the number of GFP-labeled 4T1 cells was calculated. In Protocol B, the clinically relevant mouse model of spontaneous breast cancer lung metastasis was used with surgical resection of the primary tumor to investigate the MV event that dictates postoperative lung metastasis. Female BALB/c mice were inoculated in the mammary fat pad with 4T1 cells. After 14-d growth, mice were anesthetized and divided into an MV group and a control (no MV) group during surgical procedures (mastectomy). Metastatic tumor burden was assessed two weeks after mastectomy by both macroscopic metastatic nodule count, hematoxylin-eosin histology, immunohistochemistry for the macrophage marker (CD68), and epithelial cell adhesion molecule (EpCAM).

RESULTS

MV was associated with a significant increase in the number of circulating breast tumor cells (GFP-labeled 4T1 cells) remaining in the microvasculature of the lung (P<0.01). Immunohistochemical results showed increased infiltration of CD68-positive macrophages within injured lung parenchyma and metastatic tumor as well as increased expression of EpCAM in metastatic nodules. Postoperative metastases were more prevalent in the mechanically ventilated mice group compared to the non-ventilated group (P<0.05).

CONCLUSION

MV-induced lung metastasis occurs by attracting circulating tumor cells to the site of the lung injury and by accelerating the proliferation of preexisting micro-metastases in the lung. These observations indicate that the metastasis-enhancing effect of MV should be considered in general anesthesia during cancer surgery.

Treatment with Src inhibitor Dasatinib results in elevated metastatic potential in the 4T1 murine mammary carcinoma model

Introduction

The src inhibitor Dasatinib has been widely studied as an anti-metastatic agent. The aims of this study were to examine the effect of Src inhibition on the metastatic potential of the 4T1 murine mammary carcinoma.

Context

Src is a non-receptor tyrosine kinase well-known to contribute to the metastatic potential of tumour cells. It does so through alteration of signalling pathways important to metastasis. Elevated levels of Src are common in many cancer types, and have been correlated with tumour progression and poor patient prognosis.

Aims

This study examined whether disruption of the Src signalling pathway could inhibit metastases formation.

Settings and Design

The Src inhibitor Dasatinib was evaluated in vitro and in vivo using the highly metastatic 4T1 murine mammary adenocarcinoma cell line.

Methods and Material

In vitro assays included growth curve, western blot, migration, and invasion assays. In vivo assays included intradermal and tail vein injection models.

Statistical analysis used

In vitro data were analysed using one-way ANOVA with Dunnett's multiple comparisons in GraphPad Prism 6.0. In vivo data were analysed using GraphPad Prism 6.0, using the Wilcoxon matched pairs test.

Results

Dasatinib is effective at inhibiting in vitro phosphorylation of Src, migration and invasion in the 4T1 cell line, as well as angiogenesis in vivo. In vitro treatment with Dasatinib impaired the metastatic ability of tumour cells as assessed by a tail vein injection model. However, both the syngeneic BALB/c and the athymic nu/nu mice receiving oral doses of the drug developed significantly higher numbers of 4T1 lung metastases. This effect was not seen in a different breast carcinoma cell line, the MDA-MB-231-4175-LM2, nor was this effect seen in the murine fibrosarcoma KHT cell line.

Conclusions

The 4T1 cell line is not an appropriate model to study Src inhibition.

Subchronic toxicity, immunoregulation and anti-breast tumor effect of Nordamnacantal, an anthraquinone extracted from the stems of Morinda citrifolia L

BACKGROUND

Morinda citrifolia L. that was reported with immunomodulating and cytotoxic effects has been traditionally used to treat multiple illnesses including cancer. An anthraquinone derived from fruits of Morinda citrifolia L., nordamnacanthal, is a promising agent possessing several in vitro biological activities. However, the in vivo anti-tumor effects and the safety profile of nordamnacanthal are yet to be evaluated.

METHODS

In vitro cytotoxicity of nordamnacanthal was tested using MTT, cell cycle and Annexin V/PI assays on human MCF-7 and MDA-MB231 breast cancer cells. Mice were orally fed with nordamnacanthal daily for 28 days for oral subchronic toxicity study. Then, the in vivo anti-tumor effect was evaluated on 4T1 murine cancer cells-challenged mice. Changes of tumor size and immune parameters were evaluated on the untreated and nordamnacanthal treated mice.

RESULTS

Nordamnacanthal was found to possess cytotoxic effects on MDA-MB231, MCF-7 and 4T1 cells in vitro. Moreover, based on the cell cycle and Annexin V results, nordamnacanthal managed to induce cell death in both MDA-MB231 and MCF-7 cells. Additionally, no mortality, signs of toxicity and changes of serum liver profile were observed in nordamnacanthal treated mice in the subchronic toxicity study. Furthermore, 50 mg/kg body weight of nordamncanthal successfully delayed the progression of 4T1 tumors in Balb/C mice after 28 days of treatment. Treatment with nordamnacanthal was also able to increase tumor immunity as evidenced by the immunophenotyping of the spleen and YAC-1 cytotoxicity assays.

CONCLUSION

Nordamnacanthal managed to inhibit the growth and induce cell death in MDA-MB231 and MCF-7 cell lines in vitro and cease the tumor progression of 4T1 cells in vivo. Overall, nordamnacanthal holds interesting anti-cancer properties that can be further explored.

Baker's Yeast Sensitizes Metastatic Breast Cancer Cells to Paclitaxel In Vitro

Our earlier studies have demonstrated that phagocytosis of baker's yeast ( Saccharomyces cerevisiae) induces apoptosis in different cancer cell lines in vitro and in vivo. This study aimed to examine how baker's yeast sensitizes murine and human breast cancer cells (BCC) to paclitaxel in vitro. This sensitizing effect makes lower concentrations of chemotherapy more effective at killing cancer cells, thereby enhancing the capacity of treatment. Three BCC lines were used: the metastatic murine 4T1 line, the murine Ehrlich ascites carcinoma (EAC) line, and the human breast cancer MCF-7 line. Cells were cultured with different concentrations of paclitaxel in the presence or absence of baker's yeast. Cell survival and the IC₅₀ values were determined by MTT assay and trypan blue exclusion method. Percent of DNA damage, apoptosis, and cell proliferation were examined by flow cytometry. Yeast alone and paclitaxel alone significantly decreased 4T1 cell viability postculture (24 and 48 hours), caused DNA damage, increased apoptosis, and suppressed cell proliferation. Baker's yeast in the presence of paclitaxel increased the sensitivity of 4T1 cells to chemotherapy and caused effects that were greater than either treatment alone. The chemosensitizing effect of yeast was also observed with murine EAC cells and human MCF-7 cells, but to a lesser extent. These data suggest that dietary baker's yeast is an effective chemosensitizer and can enhance the apoptotic capacity of paclitaxel against breast cancer cells in vitro. Baker's yeast may represent a novel adjuvant for chemotherapy treatment.

Green synthesis of selenium nanoparticles using Acinetobacter sp. SW30: optimization, characterization and its anticancer activity in breast cancer cells

The aim of this study was to synthesize selenium nanoparticles (SeNPs) using cell suspension and total cell protein of Acinetobacter sp. SW30 and optimize its synthesis by studying the influence of physiological and physicochemical parameters. Also, we aimed to compare its anticancer activity with that of chemically synthesized SeNPs in breast cancer cells. Cell suspension of Acinetobacter sp. SW30 was exposed to various physiological and physicochemical conditions in the presence of sodium selenite to study their effects on the synthesis and morphology of SeNPs. Breast cancer cells (4T1, MCF-7) and noncancer cells (NIH/3T3, HEK293) were exposed to different concentrations of SeNPs. The 18 h grown culture with 2.7×10⁹ cfu/mL could synthesize amorphous nanospheres of size 78 nm at 1.5 mM and crystalline nanorods at above 2.0 mM Na₂SeO₃ concentration. Polygonal-shaped SeNPs of average size 79 nm were obtained in the supernatant of 4 mg/mL of total cell protein of Acinetobacter sp. SW30. Chemical SeNPs showed more anticancer activity than SeNPs synthesized by Acinetobacter sp. SW30 (BSeNPs), but they were found to be toxic to noncancer cells also. However, BSeNPs were selective against breast cancer cells than chemical ones. Results suggest that BSeNPs are a good choice of selection as anticancer agents.

Effects of Epirubicin and Cisplatin Against 4T1 Breast Cancer Cells are Enhanced by Myrtucommulone-A

BACKGROUND

The number of cancer cases around the world has increased according to the World Health Organization (WHO) reports, nearly 14 million new cases and 8.2 million cancer associated mortalities have been reported in 2012. Chemotherapeutic resistance is a major problematic issue in the management of patients with breast tumor.

OBJECTIVE

In this study, the apoptotic gene profile of 4T1 mouse breast cancer cells treated with MC-A in combination with cisplatin or epirubicin was evaluated to decipher the possible apoptotic molecular targets.

METHODS

The effects of MC-A in combination with cisplatin (CIS) or epirubicin (EPI) on cytotoxicity, cell migration, wound healing, clonogenicity along with enhanced effect of these combinations on 84 apoptosis related genes were tested in 4T1 cancer cells.

RESULTS

MC-A in combination with epirubicin or cisplatin robustly induced cytotoxicity in 4T1 cells in vitro. MC-A in combination with cisplatin or epirubicin showed significantly inhibition of cell migration compared to treatment with each agent alone. Genes involved in positive regulation of apoptosis, negative regulator of apoptosis, death-like, mitochondrial apoptotic signaling, induction of apoptosis through DR3 and DR4/5 death receptors, and anti-apoptosis were highly affected in MC-A+cisplatin or MC-A+epirubicin combinations compared to each agent only.

CONCLUSIONS

In conclusion, the apoptotic response of 4T1 cancer cells to chemotherapeutic drugs occurs in different ways. MC-A in combination with these chemotherapeutic drugs could modulate the expression of genes involved in both extrinsic and intrinsic pathways of apoptosis, leading to higly effective apoptotic signalling in cancer treatment.

Arginase inhibition suppresses lung metastasis in the 4T1 breast cancer model independently of the immunomodulatory and anti-metastatic effects of VEGFR-2 blockade

Tumor angiogenesis promotes tumor growth and metastasis. Anti-angiogenic therapy in combination with chemotherapy is used for the treatment of metastatic cancers, including breast cancer but therapeutic benefits are limited. Mobilization and accumulation of myeloid-derived suppressor cells (MDSC) during tumor progression and therapy have been implicated in metastasis formation and resistance to anti-angiogenic treatments. Here, we used the 4T1 orthotopic syngenic mouse model of mammary adenocarcinoma to investigate the effect of VEGF/VEGFR-2 axis inhibition on lung metastasis, MDSC and regulatory T cells (Tregs). We show that treatment with the anti-VEGFR-2 blocking antibody DC101 inhibits primary tumor growth, angiogenesis and lung metastasis. DC101 treatment had no effect on MDSC mobilization, but partially attenuated the inhibitory effect of mMDSC on T cell proliferation and decreased the frequency of Tregs in primary tumors and lung metastases. Strikingly, DC101 treatment induced the expression of the immune-suppressive molecule arginase I in mMDSC. Treatment with the arginase inhibitor N^ω-hydroxy-nor-Arginine (Nor-NOHA) reduced the inhibitory effect of MDSC on T cell proliferation and inhibited number and size of lung metastasis but had little or no additional effects in combination with DC101. In conclusion, DC101 treatment suppresses 4T1 tumor growth and metastasis, partially reverses the inhibitory effect of mMDSC on T cell proliferation, decreases Tregs in tumors and increases arginase I expression in mMDSC. Arginase inhibition suppresses lung metastasis independently of DC101 effects. These observations contribute to the further characterization of the immunomodulatory effect of anti-VEGF/VEGFR2 therapy and provide a rationale to pursue arginase inhibition as potential anti-metastatic therapy.

In vitro Cytotoxicity Effects of 197Au/PAMAMG4 and 198Au/PAMAMG4 Nanocomposites Against MCF7 and 4T1 Breast Cancer Cell Lines

Purpose: Study on gold based therapeutic agents for cancer cells deracination has become under scrutiny in recent years owing to effective treatments are not available for rapidly progressive cancers. The aim of present study was to examine efficiency of radioactive 198Au/PAMAMG4 and non-radioactive 197Au/PAMAMG4 nancomposites against 4T1 and MCF7 breast cancer cell lines. Methods: The PAMAMG4 dendrimer was treated with the gold anions and then, the mixture was chemically reduced by NaBH4. Prepared 197Au/PAMAMG4 was bombarded by thermal neutrons in the Tehran Research Reactor to 198Au/PAMAMG4 be produced. Prepared nanocomposites were characterized by means of FT-IR, 1H NMR, Zeta-potential measurements, TEM and EDX analyses. The radionuclidic purity of the 198Au/PAMAMG4 solution was determined using purity germanium (HPGe) spectroscopy and its stability in the presence of human serum was studied. In vitro studies were carried out to compare toxicity of PAMAMG4, 197Au/PAMAMG4 and 198Au/PAMAMG4 towards 4T1 and MCF7 cancerous cells and C2C12 normal cell lines. Results: Characterization results exhibited that invitro agents, 197Au/PAMAMG4 and 198Au/PAMAMG4, were synthesized successfully. Cells viability after 24 h, 48 h, and 72 h incubation, using MTT assay showed that the toxicity of 198Au/PAMAMG4 is significantly superior in comparison with 197Au/PAMAMG4 and PAMAMG4. Furthermore, the toxicity of 198Au/PAMAMG4 was higher on cancerous cells especially in higher level of concentrations after 72 hours (P<0.05). Conclusion: In the current study, the preparation of 197Au/PAMAMG4 and 198Au/PAMAMG4 is described and the cytotoxic properties of them against the MCF7, 4T1 cancerous cells and C2C12 normal cells were evaluated using MTT assay.

Reelin Deficiency Delays Mammary Tumor Growth and Metastatic Progression

Reelin is a regulator of cell migration in the nervous system, and has other functions in the development of a number of non-neuronal tissues. In addition, alterations in reelin expression levels have been reported in breast, pancreatic, liver, gastric, and other cancers. Reelin is normally expressed in mammary gland stromal cells, but whether stromal reelin contributes to breast cancer progression is unknown. Herein, we used a syngeneic mouse mammary tumor transplantation model to examine the impact of host-derived reelin on breast cancer progression. We found that transplanted syngeneic tumors grew more slowly in reelin-deficient (rl ^{Orl -/-} ) mice and had delayed metastatic colonization of the lungs. Immunohistochemistry of primary tumors revealed that tumors grown in rl ^{Orl -/-} animals had fewer blood vessels and increased macrophage infiltration. Gene expression studies from tumor tissues indicate that loss of host-derived reelin alters the balance of M1- and M2-associated macrophage markers, suggesting that reelin may influence the polarization of these cells. Consistent with this, rl ^{Orl -/-} M1-polarized bone marrow-derived macrophages have heightened levels of the M1-associated cytokines iNOS and IL-6. Based on these observations, we propose a novel function for the reelin protein in breast cancer progression.