Dynamic changes in B cell subpopulations in response to triple-negative breast cancer development

Despite presenting a worse prognosis and being associated with highly aggressive tumors, triple-negative breast cancer (TNBC) is characterized by the higher frequency of tumor-infiltrating lymphocytes, which have been implicated in better overall survival and response to therapy. Though recent studies have reported the capacity of B lymphocytes to recognize overly-expressed normal proteins, and tumor-associated antigens, how tumor development potentially modifies B cell response is yet to be elucidated. Our findings reveal distinct effects of 4T1 and E0771 murine tumor development on B cells in secondary lymphoid organs. Notably, we observe a significant expansion of total B cells and plasma cells in the tumor-draining lymph nodes (tDLNs) as early as 7 days after tumor challenge in both murine models, whereas changes in the spleen are less pronounced. Surprisingly, within the tumor microenvironment (TME) of both models, we detect distinct B cell subpopulations, but tumor development does not appear to cause major alterations in their frequency over time. Furthermore, our investigation into B cell regulatory phenotypes highlights that the B10 Breg phenotype remains unaffected in the evaluated tissues. Most importantly, we identified an increase in CD19 + LAG-3 + cells in tDLNs of both murine models. Interestingly, although CD19 + LAG-3 + cells represent a minor subset of total B cells (< 3%) in all evaluated tissues, most of these cells exhibit elevated expression of IgD, suggesting that LAG-3 may serve as an activation marker for B cells. Corroborating with these findings, we detected distinct cell cycle and proliferation genes alongside LAG-3 analyzing scRNA-Seq data from a cohort of TNBC patients. More importantly, our study suggests that the presence of LAG-3 B cells in breast tumors could be associated with a good prognosis, as patients with higher levels of LAG-3 B cell transcripts had a longer progression-free interval (PFI). This novel insight could pave the way for targeted therapies that harness the unique properties of LAG-3 + B cells, potentially offering new avenues for improving patient outcomes in TNBC. Further research is warranted to unravel the mechanistic pathways of these cells and to validate their prognostic value in larger, diverse patient cohorts.

ADAM10 and Neprilysin level decreases in immune cells of mice bearing metastatic breast carcinoma: Possible role in cancer inflammatory response

OBJECTIVE AND DESIGN

ADAM10 and Neprilysin, proteases, play critical role in inflammatory disease, however their role in cancer immune response is not clear. We here evaluated changes in immune response using an experimental model for breast cancer.

MATERIAL AND METHOD

Highly metastatic breast cancer cells (4T1-derived) were injected orthotopically (mammary-pad of Balb-c mice) to induce tumors. Changes in enzyme level and activity as well as alterations in inflammatory cytokine release in the presence or absence of ADAM10 and NEP activity was determined using specific inhibitors and recombinant proteins. Cytokine response was evaluated using mix leucocyte cultures obtained from control and tumor-bearing mice. ANOVA with Dunnett's posttest was used for statistical analysis.

RESULTS

ADAM10 and NEP expression was decreased markedly in lymph nodes and spleens of tumor-bearing mice. ADAM10 activity was reduced together with apparent alterations of ADAM10 processing. ADAM10 and NEP activity decreased TNF-α, IL-6 and IFN-ɣ secretion. Suppression of these inflammatory cytokines were more prominent in cultures obtained from control mice demonstrating counteracting factors that are exist in tumor-bearing mice.

CONCLUSION

Loss of ADAM10 and NEP activity in immune cells during breast cancer metastasis might be one of the main factors involved in induction of chronic inflammation by tumors.

Assessing the Therapeutic Efficacy of Proton Transport Inhibitors in a Triple-Negative Breast Cancer Murine Model with Magnetic Resonance Imaging-Chemical Exchange Saturation Transfer Tumor pH Imaging

Proton transporters play a key role in maintaining the acidic tumor microenvironment; hence, their inhibition has been proposed as a new therapeutic treatment, although few methods can accurately assess their effect in vivo. In this study, we investigated whether MRI-CEST (Magnetic Resonance Imaging-Chemical Exchange Saturation Transfer) tumor pH imaging can be a useful tool to evaluate in vivo the therapeutic efficacy of several Proton Pump Inhibitors (PPIs) in breast cancer. Cell viability and extracellular pH assays were carried out in breast cancer cells cultured at physiological pH (7.4) or acid-adapted (pH of 6.5 and 6.8) following the exposure to inhibitors of V-ATPase (Lansoprazole, Esomeprazole) or NHE1 (Amiloride, Cariporide) at several concentrations. Next, triple-negative breast cancer 4T1 tumor-bearing mice were treated with Lansoprazole or Amiloride and MRI-CEST tumor pH imaging was utilized to assess the in vivo efficacy. Only Lansoprazole induced, in addition to breast cancer cell toxicity, a significant inhibition of proton extrusion. A significant reduction in tumor volume, prolonged survival, and increase in extracellular tumor pH after 1 and 2 weeks were observed after Lansoprazole treatment, whereas no significant changes were detected upon Amiloride treatment. Our results suggested that MRI-CEST tumor pH imaging can monitor the therapeutic efficacy of PPIs in breast cancer murine models.

Combination of verteporfin-photodynamic therapy with 5-aza-2'-deoxycytidine enhances the anti-tumour immune response in triple negative breast cancer

Introduction

Triple negative breast cancer (TNBC) is a subtype of breast cancer characterised by its high tumourigenic, invasive, and immunosuppressive nature. Photodynamic therapy (PDT) is a focal therapy that uses light to activate a photosensitizing agent and induce a cytotoxic effect. 5-aza-2'-deoxycytidine (5-ADC) is a clinically approved immunomodulatory chemotherapy agent. The mechanism of the combination therapy using PDT and 5-ADC in evoking an anti-tumour response is not fully understood.

Methods

The present study examined whether a single dose of 5-ADC enhances the cytotoxic and anti-tumour immune effect of low dose PDT with verteporfin as the photosensitiser in a TNBC orthotopic syngeneic murine model, using the triple negative murine mammary tumour cell line 4T1. Histopathology analysis, digital pathology and immunohistochemistry of treated tumours and distant sites were assessed. Flow cytometry of splenic and breast tissue was used to identify T cell populations. Bioinformatics were used to identify tumour immune microenvironments related to TNBC patients.

Results

Functional experiments showed that PDT was most effective when used in combination with 5-ADC to optimize its efficacy. 5-ADC/PDT combination therapy elicited a synergistic effect in vitro and was significantly more cytotoxic than monotherapies on 4T1 tumour cells. For tumour therapy, all types of treatments demonstrated histopathologically defined margins of necrosis, increased T cell expression in the spleen with absence of metastases or distant tissue destruction. Flow cytometry and digital pathology results showed significant increases in CD8 expressing cells with all treatments, whereas only the 5-ADC/PDT combination therapy showed increase in CD4 expression. Bioinformatics analysis of in silico publicly available TNBC data identified BCL3 and BCL2 as well as the following anti-tumour immune response biomarkers as significantly altered in TNBC compared to other breast cancer subtypes: GZMA, PRF1, CXCL1, CCL2, CCL4, and CCL5. Interestingly, molecular biomarker assays showed increase in anti-tumour response genes after treatment. The results showed concomitant increase in BCL3, with decrease in BCL2 expression in TNBC treatment. In addition, the treatments showed decrease in PRF1, CCL2, CCL4, and CCL5 genes with 5-ADC and 5-ADC/PDT treatment in both spleen and breast tissue, with the latter showing the most decrease.

Discussion

To our knowledge, this is the first study that shows which of the innate and adaptive immune biomarkers are activated during PDT related treatment of the TNBC 4T1 mouse models. The results also indicate that some of the immune response biomarkers can be used to monitor the effectiveness of PDT treatment in TNBC murine model warranting further investigation in human subjects.

Exosomes derived from rapamycin-treated 4T1 breast cancer cells induced polarization of macrophages to M1 phenotype

M2 macrophages are the most prevalent type in the tumor microenvironment and their polarization to M1 type can be used as a potential cancer immunotherapy. Here, we investigated the role of tumor microenvironment and particularly purified exosomes in M2 to M1 macrophage polarization. Rapamycin treatment on triple-negative breast cancer cells (TNBC) was performed. Tumor cells-derived exosomes (called texosomes) were isolated and characterized using scanning electron microscopy, transmission electron microscopy, dynamic light scattering, high-performance liquid chromatography, Fourier transform infrared, and Western blot assays. M2 mouse peritoneal macrophages were treated with rapamycin or rapamycin-texosome. Then, M1/M2 phenotype-specific marker genes and proteins were measured to assess the degree of M2 to M1 polarization. Finally, nitric oxide (NO) production, phagocytosis, and efferocytosis assays were assessed to verify the functionality of the polarized macrophages. Purified rapamycin-texosomes significantly increased the expression of the M1 markers (Irf5, Nos2, and CD86) and decreased M2 markers (Arg, Ym1, and CD206). In addition, the levels of M1-specific cytokines tumor necrosis factor alpha and interleukin 1β (IL-1β) were increased, whereas the levels of M2 specific cytokines IL-10 and transforming growth factor beta were declined. Furthermore, texosome treatment increased NO concentration and phagocytosis and decreased efferocytosis indicating M1 polarization. These findings suggest rapamycin-texosomes can induce M2 to M1 macrophages polarization as a potential immunotherapy for TNBC.

Bisphenol A increases the size of primary mammary tumors and promotes metastasis in a murine model of breast cancer

Triple negative breast cancer (TNBC) is a subtype of breast tumor characterized for the absence of estrogen and progesterone receptors expression and low HER2/neu expression. Bisphenol A (BPA) is an endocrine disrupting chemical with estrogenic activity that has been associated with increasing rates of breast cancer. Moreover, BPA is a solid organic synthetic chemical employed in the manufacture of many consumer products, epoxy resins and polycarbonate plastics including baby bottles, containers for food and beverages, and the lining of beverage cans. The G-protein-coupled estrogen receptor (GPER) is activated by endogenous hormones and synthetic ligands, such as BPA. GPER is expressed in TNBC cells and its expression is associated with larger tumor size, metastasis and worse survival prognosis. In breast cancer cells, BPA induces activation of signal transduction pathways that mediates migration and invasion via GPER in human TNBC MDA-MB-231 cells. In this study, we demonstrate that BPA induces an increase of GPER expression and its translocation from cytosol to cytoplasmic membrane, metalloproteinase (MMP)-2 and MMP-9 secretion, migration and invasion in murine TNBC 4T1 cells. In a murine TNBC model "in vivo" using 4T1 cells, BPA induces the formation of mammary tumors with more weight and volume, and an increase in the number of mice with metastasis to lung and nodules in lung compared with tumors and metastasis to lung of untreated Balb/cJ mice. In conclusion, our findings demonstrate that BPA mediates the growth of mammary primary tumors and metastasis to lung in a murine model of breast cancer.

Regression and Eradication of Triple-Negative Breast Carcinoma in 4T1 Mouse Model by Combination Immunotherapies

Triple-negative breast carcinoma (TNBC) is one of the most aggressive types of solid-organ cancers. While immune checkpoint blockade (ICB) therapy has significantly improved outcomes in certain types of solid-organ cancers, patients with immunologically cold TNBC are afforded only a modest gain in survival by the addition of ICB to systemic chemotherapy. Thus, it is urgently needed to develop novel effective therapeutic approaches for TNBC. Utilizing the 4T1 murine model of TNBC, we developed a novel combination immunotherapeutic regimen consisting of intratumoral delivery of high-mobility group nucleosome binding protein 1 (HMGN1), TLR2/6 ligand fibroblast-stimulating lipopeptide (FSL-1), TLR7/8 agonist (R848/resiquimod), and CTLA-4 blockade. We also investigated the effect of adding SX682, a small-molecule inhibitor of CXCR1/2 known to reduce MDSC trafficking to tumor microenvironment, to our therapeutic approach. 4T1-bearing mice responded with significant tumor regression and tumor elimination to our therapeutic combination regimen. Mice with complete tumor regressions did not recur and became long-term survivors. Treatment with HMGN1, FSL-1, R848, and anti-CTLA4 antibody increased the number of infiltrating CD4+ and CD8+ effector/memory T cells in both tumors and draining lymph nodes and triggered the generation of 4T1-specific cytotoxic T lymphocytes (CTLs) in the draining lymph nodes. Thus, we developed a potentially curative immunotherapeutic regimen consisting of HMGN1, FSL-1, R848, plus a checkpoint inhibitor for TNBC, which does not rely on the administration of chemotherapy, radiation, or exogenous tumor-associated antigen(s).

Tumor-derived interleukin-34 creates an immunosuppressive and chemoresistant tumor microenvironment by modulating myeloid-derived suppressor cells in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype characterized by a lack of therapeutic targets. The paucity of effective treatment options motivated a number of studies to tackle this problem. Immunosuppressive cells infiltrated into the tumor microenvironment (TME) of TNBC are currently considered as candidates for new therapeutic targets. Myeloid-derived suppressor cells (MDSCs) have been reported to populate in the TME of TNBC, but their roles in the clinical and biological features of TNBC have not been clarified. This study identified that interleukin-34 (IL-34) released by TNBC cells is a crucial immunomodulator to regulate MDSCs accumulation in the TME. We provide evidence that IL-34 induces a differentiation of myeloid stem cells into monocytic MDSCs (M-MDSCs) that recruits regulatory T (Treg) cells, while suppressing a differentiation into polymorphonuclear MDSCs (PMN-MDSCs). As a result, the increase in M-MDSCs contributes to the creation of an immunosuppressive TME, and the decrease in PMN-MDSCs suppresses angiogenesis, leading to an acquisition of resistance to chemotherapy. Accordingly, blockade of M-MDSC differentiation with an estrogen receptor inhibitor or anti-IL-34 monoclonal antibody suppressed M-MDSCs accumulation causing retardation of tumor growth and restores chemosensitivity of the tumor by promoting PMN-MDSCs accumulation. This study demonstrates previously poorly understood mechanisms of MDSCs-mediated chemoresistance in the TME of TNBC, which is originated from the existence of IL-34, suggesting a new rationale for TNBC treatment.

Gemini curcumin inhibits 4T1 cancer cell proliferation and modulates the expression of apoptotic and metastatic genes in Balb/c mice model

BACKGROUND

Despite the attractive anti-cancer effects, poor solubility and low bioavailability have restricted the clinical application of Curcumin. Recent findings show that Gemini nano-curcumin (Gemini-Cur) significantly improves the cellular uptake of Curcumin and its anti-cancer effect in tumor cells. Here, we aimed to assess the suppressive effect of Gemini-Cur on 4T1 breast cancer cells in vitro and, subsequently, in BALB/c mouse models.

MATERIALS AND METHODS

Fluorescence microscopy was employed to visualize cellular uptake and morphological changes of 4T1 cells during treatment with Gemini-Cur and void curcumin. MTT and annexin V/FITC assays were performed to study the toxic effect of Gemini-Cur on mouse cancer cells. For in vivo studies, BALB/c tumor-bearing mice were used to evaluate the inhibitory effect of Gemini-Cur in comparison with mice receiving free Curcumin and nanoparticles.

RESULTS

Our data showed that Gemini-Cur enters the cells and inhibits proliferation in a time- and dose-dependent manner. Annexin V/FITC confirmed apoptotic effect on 4T1 cells. In vivo studies also illustrated that tumor growth is suppressed in Gemini-Cur treated mice rather than controls. Expression studies demonstrated the modulation of apoptotic and metastatic genes, including Bax, Bcl-2, MMP-9, VEGF, and COX-2 in treated mice.

CONCLUSION

In conclusion, these data demonstrate the promising anti-cancer properties of Gemini-Cur on mice models. However, further studies at molecular and cellular levels are required to conclude this therapeutic advantage.

NSC243928 Treatment Induces Anti-Tumor Immune Response in Mouse Mammary Tumor Models

NSC243928 induces cell death in triple-negative breast cancer cells in a LY6K-dependent manner. NSC243928 has been reported as an anti-cancer agent in the NCI small molecule library. The molecular mechanism of NSC243928 as an anti-cancer agent in the treatment of tumor growth in the syngeneic mouse model has not been established. With the success of immunotherapies, novel anti-cancer drugs that may elicit an anti-tumor immune response are of high interest in the development of novel drugs to treat solid cancer. Thus, we focused on studying whether NSC243928 may elicit an anti-tumor immune response in the in vivo mammary tumor models of 4T1 and E0771. We observed that NSC243928 induced immunogenic cell death in 4T1 and E0771 cells. Furthermore, NSC243928 mounted an anti-tumor immune response by increasing immune cells such as patrolling monocytes, NKT cells, B1 cells, and decreasing PMN MDSCs in vivo. Further studies are required to understand the exact mechanism of NSC243928 action in inducing an anti-tumor immune response in vivo, which can be used to determine a molecular signature associated with NSC243928 efficacy. NSC243928 may be a good target for future immuno-oncology drug development for breast cancer.

Molecular Imaging of Oxygenation Changes during Immunotherapy in Combination with Paclitaxel in Triple Negative Breast Cancer

Hypoxia is a common feature of the tumor microenvironment, including that of triple-negative breast cancer (TNBC), an aggressive breast cancer subtype with a high five-year mortality rate. Using [18F]-fluoromisonidazole (FMISO) positron emission tomography (PET) imaging, we aimed to monitor changes in response to immunotherapy (IMT) with chemotherapy in TNBC. TNBC-tumor-bearing mice received paclitaxel (PTX) ± immune checkpoint inhibitors anti-programmed death 1 and anti-cytotoxic T-lymphocyte 4. FMISO-PET imaging was performed on treatment days 0, 6, and 12. Max and mean standard uptake values (SUVmax and SUVmean, respectively), histological analyses, and flow cytometry results were compared. FMISO-PET imaging revealed differences in tumor biology between treatment groups prior to tumor volume changes. 4T1 responders showed SUVmean 1.6-fold lower (p = 0.02) and 1.8-fold lower (p = 0.02) than non-responders on days 6 and 12, respectively. E0771 responders showed SUVmean 3.6-fold lower (p = 0.001) and 2.7-fold lower (p = 0.03) than non-responders on days 6 and 12, respectively. Immunohistochemical analyses revealed IMT plus PTX decreased hypoxia and proliferation and increased vascularity compared to control. Combination IMT/PTX recovered the loss of CD4+ T-cells observed with single-agent therapies. PET imaging can provide timely, longitudinal data on the TNBC tumor microenvironment, specifically intratumoral hypoxia, predicting therapeutic response to IMT plus chemotherapy.

Cellulose Nanofiber-Coated Perfluoropentane Droplets: Fabrication and Biocompatibility Study

Purpose

To study the effect of cellulose nanofiber (CNF)-shelled perfluoropentane (PFP) droplets on the cell viability of 4T1 breast cancer cells with or without the addition of non-encapsulated paclitaxel.

Methods

The CNF-shelled PFP droplets were produced by mixing a CNF suspension and PFP using a homogenizer. The volume size distribution and concentration of CNF-shelled PFP droplets were estimated from images taken with an optical microscope and analyzed using Fiji software and an in-house Matlab script. The thermal stability was qualitatively assessed by comparing the size distribution and concentration of CNF-shelled PFP droplets at room temperature (~22°) and 37°C. The cell viability of 4T1 cells was measured using a 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, a hemolysis assay was performed to assess blood compatibility of CNF-shelled PFP droplets.

Results

The droplet diameter and concentration of CNF-shelled PFP droplets decreased after 48 hours at both room temperature and 37°C. In addition, the decrease in concentration was more significant at 37°C, from 3.50 ± 0.64×10⁶ droplets/mL to 1.94 ± 0.10×10⁶ droplets/mL, than at room temperature, from 3.65 ± 0.29×10⁶ droplets/mL to 2.56 ± 0.22×10⁶ droplets/mL. The 4T1 cell viability decreased with increased exposure time and concentration of paclitaxel, but it was not affected by the presence of CNF-shelled PFP droplets. No hemolysis was observed at any concentration of CNF-shelled PFP droplets.

Conclusion

CNF-shelled PFP droplets have the potential to be applied as drug carriers in ultrasound-mediated therapy.

Mathematical Model of Triple-Negative Breast Cancer in Response to Combination Chemotherapies

Triple-negative breast cancer (TNBC) is a heterogenous disease that is defined by its lack of targetable receptors, thus limiting treatment options and resulting in higher rates of metastasis and recurrence. Combination chemotherapy treatments, which inhibit tumor cell proliferation and regeneration, are a major component of standard-of-care treatment of TNBC. In this manuscript, we build a coupled ordinary differential equation model of TNBC with compartments that represent tumor proliferation, necrosis, apoptosis, and immune response to computationally describe the biological tumor affect to a combination of chemotherapies, doxorubicin (DRB) and paclitaxel (PTX). This model is parameterized using longitudinal [18F]-fluorothymidine positron emission tomography (FLT-PET) imaging data which allows for a noninvasive molecular imaging approach to quantify the tumor proliferation and tumor volume measurements for two murine models of TNBC. Animal models include a human cell line xenograft model, MDA-MB-231, and a syngeneic 4T1 mammary carcinoma model. The mathematical models are parameterized and the percent necrosis at the end time point is predicted and validated using histological hematoxylin and eosin (H&E) data. Global Sobol' sensitivity analysis is conducted to further understand the role each parameter plays in the model's goodness of fit to the data. In both the MDA-MB-231 and the 4T1 tumor models, the designed mathematical model can accurately describe both tumor volume changes and final necrosis volume. This can give insight into the ordering, dosing, and timing of DRB and PTX treatment. More importantly, this model can also give insight into future novel combinations of therapies and how the immune system plays a role in therapeutic response to TNBC, due to its calibration to two types of TNBC murine models.

Cancer Progression Is not Different in Mice of Different Gender Inoculated With Cells of the Triple-Negative 4T1 Breast Cancer Model

BACKGROUND

Breast cancer in men is a rare and poorly studied disease, and its treatment is based on women breast cancer studies. However, clinical outcome is not the same in men and women. Basic studies and clinical trials in animal models provide detailed information on cancer, origin, development, cell signaling pathways, sites of metastasis, and target molecules. It is necessary to explore the biology of breast cancer in male animal models that allow observing their similarity.

METHODS

The triple-negative 4T1 breast cancer model was developed in both male and female mice and studied weekly during 4 weeks. For that, twenty 8-week-old female and male BALB/c mice were used. Sixteen mice (eight males and eight females) were inoculated into the second left thoracic mammary pad with 20,000 4T1 cells, resuspended in 20 µL phosphate-buffered saline (PBS). All samples were processed for immunodetection, characterized histopathologically and immunohistochemically.

RESULTS

In this work, we describe the development of a triple-negative 4T1 breast cancer model in male BALB/c mice. Breast tumors were characterized histopathologically at different time points and corresponded to a moderately differentiated invasive ductal carcinoma, estrogen receptor ER-/progesterone receptor PR-/human epidermal growth factor receptor 2 HER2-/Ki67+, with histological grade II (moderately differentiated; a solid mass with occasional duct formation and moderate to severe nuclear pleomorphism), infiltrating the adipose and muscular tissue, and metastasis to lungs. From the results, we did not observe differences in the time of tumor development, necrosis, color change of tumor tissue, and lung metastasis between male and female mice. Even though we did not find histological differences, response to treatment and molecular signaling may be different.

CONCLUSIONS

The histogenesis of male breast tumors was similar to that of female BALB/c mice. The histological and immunohistochemical characteristics of male tumors also match the features reported for stage IV human breast cancer of men and women. The murine male breast cancer model described here can be a significant tool to explore the molecular mechanisms involved in male breast cancer tumorigenesis and metastasis and may bring new approaches for clinical treatment of triple-negative breast cancer in men.

Cloning, expression and characterization of a peptibody to deplete myeloid derived suppressor cells in a murine mammary carcinoma model

BACKGROUND

Myeloid derived suppressor cells (MDSCs) are an immature heterogeneous population of myeloid lineage that attenuate the anti-tumor immune responses. Depletion of MDSCs has been shown to improve efficacy of cancer immunotherapeutic approaches. Here, we expressed and characterized a peptibody which had previously been defined by phage display technique capable of recognizing and depleting murine MDSCs.

MATERIALS AND METHODS

Using splicing by overlap extension (SOE) PCR, the coding sequence of the MDSC binding peptide and linker were synthesized and then ligated into a home-made expression plasmid containing mouse IgG2a Fc. The peptibody construct was transfected into CHO-K1 cells by lipofectamine 3000 reagent and the resulting fusion protein was purified with protein G column and subsequently characterized by ELISA, SDS-PAGE and immunoblotting. The binding profile of the peptibody to splenic MDSCs and its MDSC depletion ability were then tested by flow cytometry.

RESULTS

The purified peptibody appeared as a 70 KDa band in Western blot. It could bind to 98.8% of splenic CD11b⁺/Gr-1⁺ MDSCs. In addition, the intratumoral MDSCs were significantly depleted after peptibody treatment compared to their PBS-treated negative control counterparts (P < 0.05).

CONCLUSION

In this study, a peptibody capable of depleting intratumoral MDSCs, was successfully expressed and purified. Our results imply that it could be considered as a potential tool for research on cancer immunotherapy.

Isolation and anticancer activity evaluation of rare Bisaryl anthraquinone antibiotics from novel Streptomyces sp. strain of NW Himalayan region

Biosynthesis of bisaryl preanthraquinone antibiotics by various microorganisms differs in monomeric subunits as well as their dimerization positions leading to different configurations. The present study relates to the production of rare bisaryl anthraquinone antibiotics by a new Streptomyces strain isolated from Shivalik region of NW Himalayas. In vitro anticancer and anti-migratory effects of Setomimycin (9,9' bisanthraquinone antibiotic) was seen with a significant reduction in the expression of both MEK as well as ERK pathways in a dose dependent manner at 6.5 μM & 8 μM concentration in HCT-116 and 5.5 μM & 7 μM concentration in MCF-7 cells. In vivo studies in aggressive orthotopic mouse mammary carcinoma model (4T1) demonstrated about 76% reduction of primary tumor weight and 90.5% reduction in the tumor volume within two weeks. In vivo pharmacokinetics study of setomimycin revealed that it can be rapidly absorbed with an adequate plasma exposure and half-life which can be linked to its in vivo efficacy.

64CuCl2 PET Imaging of 4T1-Related Allograft of Triple-Negative Breast Cancer in Mice

⁶⁴CuCl₂ is an economic radiotracer for oncologic PET investigations. In the present study, we characterized the uptake of ⁶⁴CuCl₂ in vivo by µPET/CT in an allograft 4T1-related mouse model (BALB/c) of advanced breast cancer. ¹⁸F-FDG was used as a comparator. Twenty-two animals were imaged 7–9 days following 4T1-cell implantation inside mammary glands. Dynamic ⁶⁴CuCl₂ µPET/CT acquisition or iterative static images up to 8 h p.i. were performed. Animal biodistribution and tumor uptake were first evaluated in vivo by µPET analysis and then assessed on tissue specimens. Concerning ¹⁸F-FDG µPET, a static acquisition was performed at 15 min and 60 min p.i. Tumor ⁶⁴CuCl₂ accumulation increased from 5 min to 4 h p.i., reaching a maximum value of 5.0 ± 0.20 %ID/g. Liver, brain, and muscle ⁶⁴CuCl₂ accumulation was stable over time. The tumor-to-muscle ratio remained stable from 1 to 8 h p.i., ranging from 3.0 to 3.7. Ex vivo data were consistent with in vivo estimations. The ¹⁸F-FDG tumor accumulation was 8.82 ± 1.03 %ID/g, and the tumor-to-muscle ratio was 4.54 ± 1.11. ⁶⁴CuCl₂ PET/CT provides good characterization of the 4T1-related breast cancer model and allows for exploration of non-glycolytic cellular pathways potentially of interest for theragnostic strategies.

Antitumor efficacy of MUC1-derived variable epitope library treatments in a mouse model of breast cancer

The identification of novel targets for cancer immunotherapy and the development of new vaccine immunogens are subjects of permanent interest. MUC1 is an overexpressed antigen found in most tumors, and its overexpression correlates with poor prognosis. Many attempts to direct the immune response against MUC1 in tumor cells have failed, including several clinical trials. We have previously developed an innovative Variable Epitope Library (VEL) vaccine platform that carries massively substituted mutant variants of defined epitopes or epitope regions as an alternative to using wild-type peptide sequences-based immunogens. Here, two murine MUC1-derived epitopes equivalent to the previously tested in cancer immunotherapy human MUC1 regions were used to generate VELs. We observed that vaccination with the 23L VEL immunogens, encompassing the entire signal peptide region of MUC1, reduces the tumor area compared to the wild-type sequence treatment. Contrastingly, vaccination with the MUC1 signal peptide-derived predicted CD8⁺+ T cell epitope-based VEL, 9MUC1spL, showed similar tumor area reduction as the wild-type treatment; however, a decrease in lung metastasis after 9MUC1spL treatment was observed. In addition, vaccination induced a large pool of CD8⁺ T cells which recognized most variant epitopes from 9MUC1spL. Also, we generated MUC1 variable number tandem repeat (VNTR)-based VELs that reduced the metastatic burden when dendritic cells and M13 recombinant bacteriophages were used as vaccine carriers. Collectively, our data demonstrate the immunogenic and antitumor properties of MUC1 signal peptide- and VNTR-derived VEL immunogens.

Amplification of the CXCR3/CXCL9 axis via intratumoral electroporation of plasmid CXCL9 synergizes with plasmid IL-12 therapy to elicit robust anti-tumor immunity

Clinical studies have demonstrated that local expression of the cytokine IL-12 drives interferon-gamma expression and recruits T cells to the tumor microenvironment, ultimately yielding durable systemic T cell responses. Interrogation of longitudinal biomarker data from our late-stage melanoma trials identified a significant on-treatment increase of intratumoral CXCR3 transcripts that was restricted to responding patients, underscoring the clinical relevance of tumor-infiltrating CXCR3⁺ immune cells. In this study, we sought to understand if the addition of DNA-encodable CXCL9 could augment the anti-tumor immune responses driven by intratumoral IL-12. We show that localized IL-12 and CXCL9 treatment reshapes the tumor microenvironment to promote dendritic cell licensing and CD8⁺ T cell activation. Additionally, this combination treatment results in a significant abscopal anti-tumor response and provides a concomitant benefit to anti-PD-1 therapies. Collectively, these data demonstrate that a functional tumoral CXCR3/CXCL9 axis is critical for IL-12 anti-tumor efficacy. Furthermore, restoring or amplifying the CXCL9 gradient in the tumors via intratumoral electroporation of plasmid CXCL9 can not only result in efficient trafficking of cytotoxic CD8⁺ T cells into the tumor but can also reshape the microenvironment to promote systemic immune response.

Transfection by Electroporation of Cancer and Primary Cells Using Nanosecond and Microsecond Electric Fields

Gene transfer into primary immune cells as well as into cell lines is essential for scientific and therapeutical applications. One of the methods used for gene transfer is electroporation (EP). EP is a method where a pulsed electric field (PEF) causes a highly transient permeability of the targeted cell membrane. In this work, we present the electrotransfection of CHO-K1, 4T1 cell lines, and primary murine DCs with detectable protein-encoding plasmids in the sub-microsecond range. Microsecond (µs)- and nanosecond (ns)-range pulsed electric field transfection protocols were used. The efficiency of electrotransfection was evaluated using green fluorescent protein (GFP)-encoding plasmids (4.7 kbp; p-EGFP-N1) and plasmids expressing a firefly luciferase and red fluorescent protein (tdTomato) (8.5 kbp; pcDNA3.1(+)/Luc2 = tdT)). It was shown that the used nsPEFs protocol (7 kV/cm × 300 ns × 100, 1 MHz) ensured a better transfection efficiency than µsPEFs (1.2 kV/cm × 100 µs × 8, 1 Hz). Plasmid size and concentration had a strong impact on the cell transfection efficiency too. We also showed that there were no significant differences in transfection efficiency between immature and mature DCs. Finally, the nsPEF protocols were successfully applied for the stable transfection of the CHO-K1 cell line with the linearized pcDNA3.1(+)/Luc2 = tdT plasmid. The results of the study are applicable in gene therapy and DNA vaccination studies for the derivation of optimal electrotransfection conditions.

A novel cocktail therapy based on quintuplet combination of oncolytic herpes simplex virus-2 vectors armed with interleukin-12, interleukin-15, GM-CSF, PD1v, and IL-7 × CCL19 results in enhanced antitumor efficacy

BACKGROUND

Selectively replicating herpes simplex virus-2 (HSV-2) vector is a promising treatment for cancer therapy. The insertion of multiple transgenes into the viral genome has been performed to improve its oncolytic activity.

METHODS

Herein, we simultaneously constructed five "armed" oncolytic viruses (OVs), designated oHSV2-IL12, -IL15, GM-CSF, -PD1v, and IL7 × CCL19. These OVs delete the ICP34.5 and ICP47 genes with the insertion of transgenes into the deleted ICP34.5 locus. The anti-tumor efficacy in vivo was tested in the syngeneic 4T1 and CT26 tumor-bearing mice model.

RESULTS

The OVs showed comparable oncolytic capability in vitro. The combination therapy of oHSV2-IL12, -IL15, GM-CSF, -PD1v, and IL7 × CCL19 exhibited the highest tumor inhibition efficacy compared with the treatment of single OV or two OVs combination.

CONCLUSIONS

The OVs armed with different transgenes combination therapy also named 5-valent oHSV2 (also called cocktail therapy) might be an effective therapeutic strategy for solid tumors.

Magnolol-loaded Cholesteryl Biguanide Conjugate Hydrochloride Nanoparticles for Triple-negative Breast Cancer Therapy

The potential of combination therapy using nanoparticle delivery systems in improving triple-negative breast cancer treatment efficacy remains to be explored. Here, we report a novel nanoparticle system using a cholesterol biguanide conjugate hydrochloride (CBH) as both a drug and carrier to load magnolol (MAG). Poly(ethylene glycol)-poly(lactic-co-glycolic acid) (mPEG-PLGA) and aminoethyl anisamide-poly(ethylene glycol)-poly(lactic-co-glycolic acid) (AEAA-PEG-PLGA) were added to form nanoparticles. Nanoparticles accumulated most in tumor tissues when the weight ratio of AEAA-PEG-PLGA to mPEG-PLGA was 4:1. MAG and CBH exerted a synergistic inhibitory effect on 4T1 cells. An in vitro study showed that nanoparticles displayed the highest tumor cell uptake rate, highest apoptosis rate, and strongest inhibitory effect on tumor cell migration and monoclonal formation. CBH might promote nanoparticle uptake by cells and lysosomal escape. After intravenous administration to mice with 4T1 breast tumors in situ, the nanoparticles inhibited tumor growth without obvious toxicity. Western blot results showed that nanoparticles altered the levels of p53, p-AKT, and p-AMPK in the tumor tissue. Moreover, cell apoptosis was found in the same area of H&E-stained and TUNEL-stained tumors treated with the nanoparticles. Collectively, this nanoparticle system provides a novel combination drug delivery strategy for treating triple-negative breast cancer.

The Growth Suppression Activity of Diosmin and PGV-1 Co-Treatment on 4T1 Breast Cancer Targets Mitotic Regulatory Proteins

Objective:

We aim to enhance the effectiveness of curcumin analog PGV-1 through co-treatment with diosmin, a citrus flavonoid, on 4T1 cells and evaluate the molecular targets underlying its effect on the cell cycle.

Methods:

Cytotoxic effects were performed by MTT assay against 4T1 cells. The May Grünwald-Giemsa staining was used to observe cell cycle arrest. The senescence was assayed with SA-ß-gal staining. Bioinformatic studies were utilized to discover protein targets of PGV-1 and diosmin on triple-negative breast cancer (TNBC) using SwissTargetPrediction, then exploration of protein targets was performed using the TCGA dataset via the UALCAN website. Kaplan-Meier was performed using GraphPad with data from the TCGA dataset via Oncoln. Using MOE 2010, we conducted the binding affinity between PGV-1 and diosmin to protein targets.

Results:

PGV-1 and diosmin showed cytotoxic effect with IC₅₀ values of 9 µM and 389 µM, respectively, and the combined cytotoxic assay exhibited a synergistic effect with a combination index (CI) of <1. PGV-arrested 4T1 cells in pro-metaphase and induced mitotic catastrophe, while the combination of diosmin with PGV-1 increased the number of mitotic catastrophes. The SA-ß-gal assay revealed that both compounds were capable of inducing senescence in 4T1 cells. Study bioinformatics and molecular docking showed that PGV-1 and diosmin target cell cycle regulatory proteins in TNBC, namely CDK1, KIF11, and AURKA. Thus, the combination of diosmin and PGV-1 modulating the cell cycle that causes senescence and catastrophic death of 4T1 cancer cells is related to the inhibition of these cell cycle proteins.

Conclusion:

Diosmin enhances the cytotoxic effect of PGV-1 synergistically on 4T1 cancer cells, which correlates to the increasing senescence and mitotic catastrophe. The synergistic effect of the co-treatment is likely to target AURKA, CDK1, and KIF11. The combination of PGV-1 and diosmin performs a potential as a combinatorial anticancer drug for TNBC.

Eupatorin Suppressed Tumor Progression and Enhanced Immunity in a 4T1 Murine Breast Cancer Model

Eupatorin is a polymethoxy flavone extracted from Orthosiphon stamineus and was reported to exhibit cytotoxic effects on several cancer cell lines. However, its effect as an anti-breast cancer agent in vivo has yet to be determined. This study aims to elucidate the potential of eupatorin as an anti-breast cancer agent in vivo using 4T1 challenged BALB/c mice model. In this article, BALB/c mice (20-22 g) challenged with 4T1 cells were treated with 5 mg/kg or 20 mg/kg eupatorin, while the untreated and healthy mice were fed with olive oil (vehicle) via oral gavage. After 28 days of experiment, the mice were sacrificed and blood was collected for serum cytokine assay, while tumors were harvested to extract RNA and protein for gene expression assay and hematoxylin-eosin staining. Organs such as spleen and lung were harvested for immune suppression and clonogenic assay, respectively. Eupatorin (20 mg/kg) was effective in delaying the tumor development and reducing metastasis to the lung compared with the untreated mice. Eupatorin (20 mg/kg) also enhanced the immunity as the population of NK1.1+ and CD8+ in the splenocytes and the serum interferon-γ were increased. Concurrently, eupatorin treatment also has downregulated the expression of pro-inflammatory and metastatic related genes (IL-1β. MMP9, TNF-α, and NF-κB). Thus, this study demonstrated that eupatorin at the highest dosage of 20 mg/kg body weight was effective in delaying the 4T1-induced breast tumor growth in the animal model.

Antitumorigenic Effect of Memantine via Interfering Glutamate Metabolism in Mouse 4T1 Breast Tumor Model

BACKGROUND

Repurposing drug is an efficient strategy as the drug discovery process is timeconsuming, laborious and costly. Memantine is already used in Alzheimer's disease to prevent neurons from excess glutamate toxicity. As cancer cells benefit from higher amounts of cellular energetics like glucose and glutamine, we used memantine to interfere with the glutamate metabolism in order to restrict cancer cells' glutamine as a source for their growth.

OBJECTIVE

To investigate the potential antitumor effect of memantine by reducing glutamate levels in 4T1 mouse breast cancer model.

METHODS

24 Balb/c female mice were subcutaneously inoculated with 4T1 cells. When tumors were palpable, memantine treatment was initiated as 5 and 10 mg/kg daily intraperitoneal injection. Tumor growth was recorded every 2-3 days. Tumor volumes, serum glutamate levels, spleen IL-6 levels, genome-wide DNA methylation levels and GSK3B. pGSK3B protein expressions were measured to enlighten the anticancer mechanism of action for memantine.

RESULTS

We found that both two doses (5 and 10mg/kg) decreased tumor growth rates and serum glutamate levels significantly (p<0.05). 10mg/kg treatment increased spleen IL-6 levels (p<0.05) and decreased genomewide DNA methylation levels. Memantine treatment decreased GSK3B protein expression levels in tumor tissue samples.

CONCLUSION

To the best of our knowledge, this is the first study that investigates the antitumor activity of memantine in a breast cancer tumor model. Our results suggest a potent anticancer mechanism of the action for memantine. Memantine decreased genome wide methylation and serum glutamate levels that are associated with a poor prognosis. Therefore, Memantine might be used for targeting glutamine metabolism in cancer treatment.

Apoptotic Effects of Melittin on 4T1 Breast Cancer Cell Line is associated with Up Regulation of Mfn1 and Drp1 mRNA Expression

BACKGROUND AND PURPOSE

Melittin, as the main ingredient of honeybee venom, that has shown anticancer properties. The present study aimed at investigating the cytotoxic impacts of melittin on 4T1 breast cancer cells.

METHODS

Hemolytic activity of different concentrations (0.125, 0.25, 0.5, 1, 2, 4, 8μg/ml) of melittin was assayed and then cytotoxicity of selected concentrations of melittin (2, 4, 8, 16, 32, and 64μg/ml), 2 and 4μg/ml of cisplatin and 0.513, 0.295 and 0.123μg/ml of doxorubicin was evaluated on 4T1 cells using MTT assay. We used Morphological evaluation and flow cytometric analysis was used. Real time PCR was also used to determine mRNA expression of Mfn1 and Drp1 genes.

RESULTS

All compounds showed anti-proliferative effects on the tumor cell line with different potencies. Melittin had higher cytotoxicity against 4T1 breast cancer cells (IC50= 32μg/ml-72h) and higher hemolytic activity (HD50= 1μg/ml), as compared to cisplatin and doxorubicin. Mellitin at 16 and 32μg/ml showed apoptotic effects on 4T1 cells according to the flow cytometric analysis. The Real time PCR analysis of Drp1 and Mfn1 expression in cells treated with 16μg/ml of melittin revealed an up-regulation in Drp1 and Mfn1 genes mRNA expression in comparison with control group. Treatment with 32μg/ml of melittin was also associated with a rise in mRNA expression of Drp1 and Mfn1 as compared to the control group.

CONCLUSION

The results of this study showed that melittin has anticancer effects on 4T1 cell lines in a dose and time dependent manner and can be a good candidate for further research on breast cancer treatment.

In vivo murine breast cancer targeting by magnetic iron nanoparticles involving L. GG cytoplasmic fraction

OBJECTIVES

Use of chemical anti-cancer drugs frequently creates serious side effects. However, probiotics are natural and treat different kinds of cancer without undesired effects.

MATERIALS AND METHODS

In this study, a nano delivery system was planned to transport the Lactobacillus rhamnosus GG (L. GG) cytoplasmic fraction (Cf) to cancerous tissue in a mouse model. Magnetic iron nanoparticles (MINPs) were synthesized and loaded with L. GG-Cf(0, 0.312, 0.625, 1.25, and 2.5 mg/ml) and were administrated for three weeks to treat experimentally induced murine breast cancer in a constant magnetic field. At the end of the trial, the treating efficacy of this complex molecule was evaluated via western blotting, immunohistochemistry, and qPCR.

RESULTS

Results showed that MINPS can deliver and accumulate L. GG-Cf in cancer tissue, and reduce the size and volume of the tumors. Additionally, in cancer tissues of treated mice with 2.5 mg/ml of Cf-MINPs, significantly induced apoptosis was seen compared with untreated mice (control), and our data proved that this induction may be due to the caspase-3 pathway.

CONCLUSION

L. GG-Cf could treat murine breast cancer, and MINPs are a suitable candidate for drug delivery because of their safety, uniformity, and magnetic properties.

Bark Fraction Induced Intrinsic Apoptotic Pathway in 4T1 Cells by Decreasing Bcl-2 and Inducing Bax Expression

BACKGROUND AND OBJECTIVE

Pterygota alata (Roxb.) R.Br. bark extract has been studied to have cytotoxic activity on 4T1 cells. This study was conducted to determine the cytotoxic activity of several fractions of Pterygota alata (Roxb.) R.Br. bark against 4T1 breast cancer cells and to investigate the most active fractions on Bcl-2 and Bax expressions.

MATERIALS AND METHODS

The bark of Pterygota alata (Roxb.) R.Br. was extracted using 80% methanol and was fractionated into fractions of n-hexane, chloroform, ethyl acetate, n-butanol and insoluble n-butanol with liquid-liquid partition. Cytotoxic tests were performed using the MTT method and expressions of Bax and Bcl-2 on 4T1 breast cancer cells were detected with immunocytochemical staining. Identification of compounds in the most active fraction using GC-MS.

RESULTS

The results showed that the most active fraction was the insoluble fraction of n-butanol (IFB) with an IC50 of 15.14 μg mL-1. IFB also decreases the expression of Bcl-2 and increases the expression of Bax.

CONCLUSION

It can be concluded that Pterygota alata (Roxb.) R.Br. bark has the potential to be developed for medical use, especially for breast cancer therapy.

(Red clover) extract synergistically inhibits brain and lung metastases in 4T1 tumor-bearing BALB/c mice

Trifolium pratense L. (Red clover-T. pratense) commonly consumed as a healthy beverage has been demonstrated to have various biological activities including antioxidant and anticancer effects. The aim of this study was to investigate the antimetastasis effects of doxorubicin (DOX) and T. pratense extract in 4T1 tumor-bearing BALB/c mice. In this study, 56 female BALB/c mice were randomly divided into seven groups (n = 8/group) to receive DOX and T. pratense extract in three different doses (100, 200, and 400 mg/kg/day) for 35 days. On day 36 after starting treatments, serum cytokines (IL-8 and IL-6) were measured. Immunohistochemical (IHC) staining was performed for GATA-3 in the brain and lung, and for CK5/6 in tumor tissues. Metastasis-related gene (matrix metalloproteinase-2 [MMP-2] and sirtuin-1 [SIRT-1]) expressions were also measured by real-time PCR. Our results showed that cotreatment with DOX and T. pratense extract improved stereological parameters (i.e., reduction in the volume of metastatic tumors) in the lung and brain and decreased the serum levels of inflammatory cytokines (IL-8 and IL-6). DOX and T. pratense extract synergistically down-regulated MMP-2 and up-regulated SIRT-1 genes, decreased the number of CK5/6-positive cells in tumor tissues, and inhibited metastasis of GATA-3-positive cells into the lung and brain. The combination of T. pratense extract and DOX synergistically inhibited the metastasis of 4T1 xenograft cells in a dose-dependent manner.

Interleukin-34 contributes to poor prognosis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype characterized by the absence of therapeutic targets. It shows rapid progression, higher relapse, and poor prognosis, so the establishment of an effective therapeutic target is required. We focused on interleukin-34 (IL-34) that is a novel cytokine relating to inflammation and tumorigenesis. It has been reported that IL-34 correlates with poor prognosis of various cancers. In this study, we evaluated the relationship of IL-34 and prognosis in TNBC using human clinical information and mice model. We found that IL-34 was highly expressed in TNBC, and the survival rate in TNBC was significantly lower in patients with high IL-34 expression. Furthermore, multivariate analysis revealed that IL-34 independently affects prognosis. In murine TNBC model, IL-34 deficiency in tumor cells decreased in vivo tumor growth and increased inflammatory cytokine production from macrophages. These results suggest that tumor-derived IL-34 creates a favorable environment for TNBC cells. Thus, we showed a novel pathological role of IL-34 in TNBC and the potential of IL-34 as a therapeutic target for it.

Optimization of a syngeneic murine model of bone metastasis

•

A method to generate bone metastases in over 95% of mice.

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Tumors can be detected within one to two weeks.

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Low rates of vital organ metastases, relative to other methods.

•

Consistent tumor localization in lower body.

•

Growth rate and consistency of tumors can be controlled by quantity of cancer cells injected.

Many cancers metastasize to the bones, particularly in cases of breast and prostate cancers. Due to the “vicious cycle” of cancer cells inducing bone resorption, which promotes further tumor growth, they are difficult to treat and may lead to extreme pain. These factors increase the urgency for emerging therapeutics that target bone metastases more specifically and effectively. Animal studies are essential to the development of any therapeutics, but also require robust animal models of human diseases. Robust animal models are often challenging to develop in the case of bone metastasis studies. Previous methods to induce bone metastasis include intracardiac, intravenous, subcutaneous via mammary fat pad, and intraosseous cancer cell injections, but these methods all have limitations. By contrast, the caudal artery route of injection offers more robust bone metastasis, while also resulting in a lower rate of vital organ metastases than that of other routes of tumor implantation. A syngeneic animal model of bone metastasis is necessary in many cancer studies, because it allows the use of immunocompetent animals, which more accurately mimic cancer development observed in immunocompetent humans. Here we present a detailed method to generate robust and easily monitored 4T1-CLL1 syngeneic bone metastases with over 95% occurrence in BALB/c mice, within two weeks. This method can potentially increase consistency between animals in bone cancer metastasis studies and reduce the number of animals needed for studying bone metastases in mice.

Comparative Molecular Analysis of Cancer Behavior Cultured In Vitro, In Vivo, and Ex Vivo

Current pre-clinical models of cancer fail to recapitulate the cancer cell behavior in primary tumors primarily because of the lack of a deeper understanding of the effects that the microenvironment has on cancer cell phenotype. Transcriptomic profiling of 4T1 murine mammary carcinoma cells from 2D and 3D cultures, subcutaneous or orthotopic allografts (from immunocompetent or immunodeficient mice), as well as ex vivo tumoroids, revealed differences in molecular signatures including altered expression of genes involved in cell cycle progression, cell signaling and extracellular matrix remodeling. The 3D culture platforms had more in vivo-like transcriptional profiles than 2D cultures. In vivo tumors had more cells undergoing epithelial-to-mesenchymal transition (EMT) while in vitro cultures had cells residing primarily in an epithelial or mesenchymal state. Ex vivo tumoroids incorporated aspects of in vivo and in vitro culturing, retaining higher abundance of cells undergoing EMT while shifting cancer cell fate towards a more mesenchymal state. Cellular heterogeneity surveyed by scRNA-seq revealed that ex vivo tumoroids, while rapidly expanding cancer and fibroblast populations, lose a significant proportion of immune components. This study emphasizes the need to improve in vitro culture systems and preserve syngeneic-like tumor composition by maintaining similar EMT heterogeneity as well as inclusion of stromal subpopulations.

IMMUNEPOTENT CRP plus doxorubicin/cyclophosphamide chemotherapy remodel the tumor microenvironment in an air pouch triple-negative breast cancer murine model

In 1889, Steven Paget postulated the theory that cancer cells require a permissive environment to grow. This permissive environment is known as the tumor microenvironment (TME) and nowadays it is evident that the TME is involved in the progression and response to therapy of solid cancer tumors. Triple-negative breast cancer is one of the most lethal types of cancer for women worldwide and chemotherapy remains the standard treatment for these patients. IMMUNEPOTENT CRP is a bovine dialyzable leukocyte extract with immunomodulatory and antitumor properties. The combination of chemotherapy and IMMUNEPOTENT CRP improves clinical parameters of breast cancer patients. In the current study, we aimed to evaluate the antitumor effect of doxorubicin/cyclophosphamide chemotherapy plus IMMUNEPOTENT CRP and its impact over the tumor microenvironment in a triple-negative breast cancer murine model. We evaluated CD8⁺, CD4⁺, T regulatory cells, memory T cells, myeloid-derived suppressor cells, CD71⁺, innate effector cells and molecules such as α-SMA, VEGF, CTLA-4, PD-L1, Gal-3, IDO, IL-2, IFN-γ, IL-12, IL-6, MCP-1, and IL-10 as part of the components of the TME. Doxorubicin/cyclophosphamide + IMMUNEPOTENT CRP decreased tumor volume, prolonged survival, increased infiltrating and systemic CD8⁺ T cells and decreased tumor suppressor molecules (such as PD-L1, Gal-3, and IL-10 among others). In conclusion, we suggest that IMMUNEPOTENT CRP act as a modifier of the TME and the immune response, potentiating or prolonging anti-tumor effects of doxorubicin/cyclophosphamide in a triple-negative breast cancer murine model.

Docetaxel-loaded solid lipid nanoparticles prevent tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells

BACKGROUND

Metastasis causes the most breast cancer-related deaths in women. Here, we investigated the antitumor effect of solid lipid nanoparticles (SLN-DTX) when used in the treatment of metastatic breast tumors using 4T1-bearing BALB/c mice.

RESULTS

Solid lipid nanoparticles (SLNs) were produced using the high-energy method. Compritol 888 ATO was selected as the lipid matrix, and Pluronic F127 and Span 80 as the surfactants to stabilize nanoparticle dispersion. The particles had high stability for at least 120 days. The SLNs' dispersion size was 128 nm, their polydispersity index (PDI) was 0.2, and they showed a negative zeta potential. SLNs had high docetaxel (DTX) entrapment efficiency (86%), 2% of drug loading and showed a controlled drug-release profile. The half-maximal inhibitory concentration (IC₅₀) of SLN-DTX against 4T1 cells was more than 100 times lower than that of free DTX after 24 h treatment. In the cellular uptake test, SLN-DTX was taken into the cells significantly more than free DTX. The accumulation in the G2-M phase was significantly higher in cells treated with SLN-DTX (73.7%) than in cells treated with free DTX (23.0%), which induced subsequent apoptosis. TEM analysis revealed that SLN-DTX internalization is mediated by endocytosis, and fluorescence microscopy showed DTX induced microtubule damage. In vivo studies showed that SLN-DTX compared to free docetaxel exhibited higher antitumor efficacy by reducing tumor volume (p < 0.0001) and also prevented spontaneous lung metastasis in 4T1 tumor-bearing mice. Histological studies of lungs confirmed that treatment with SLN-DTX was able to prevent tumor. IL-6 serum levels, ki-67 and BCL-2 expression were analyzed and showed a remarkably strong reduction when used in a combined treatment.

CONCLUSIONS

These results indicate that DTX-loaded SLNs may be a promising carrier to treat breast cancer and in metastasis prevention.

Disease progression model of 4T1 metastatic breast cancer

Cancer metastasis is the main cause of death in various types of cancer. However, in the field of pharmacometrics, cancer disease progression models focus on the growth of primary tumors with tumor volume or weight as target values, while the metastasis process is less mentioned. We propose a series of mathematical models to quantitatively describe and predict the disease progression of 4T1 breast cancer in the aspect of primary breast tumor, lung metastasis and white blood cell. The 4T1 cells were injected into breast fat pad of female BALB/c mice to establish an animal model of breast cancer metastasis. The number and volume of lung metastases at different times were measured. Based on the above data, a disease progression model of breast cancer lung metastasis was established and parameter values were estimated. The white blood cell growth and the primary tumor growth of 4T1 mouse are also modeled. The established models can describe the lung metastasis of 4T1 breast cancer in three aspects: (1) the increase in metastasis number; (2) the growth of metastasis volume; (3) metastasis number-size distribution at different time points. Compared with the prior metastasis models based on von Forester equation, our models distinguished the growth rate of primary tumor and metastasis and got parameter values for 4T1 mouse model. And the current models optimized the metastasis number-size distribution model by utilizing logistic function instead of the prior power function. This study provides a comprehensive description of lung metastasis progression for 4T1 breast cancer model, as well as an alternative disease progression model structure for further pharmacodynamics modeling.

Lipophilic Near-Infrared Dyes for In Vivo Fluorescent Cell Tracking

Cells can be easily and noninvasively tracked in the body by labeling them with a lipophilic, near-infrared dye and using a live fluorescence imaging system to image the position of the dye in the body. Near-infrared dyes provide several advantages, primarily that tissue is mostly highly transparent to near-infrared light, resulting in clearer and more accurate images. Briefly, cells are labeled with a near-infrared dye such as DiR and injected into a disease model. The model is then imaged using the live fluorescence imaging system on an hourly and/or daily basis to track cell migration and final location. The relative number of cells that migrate to the desired location can be measured by measuring the fluorescent intensity at the location versus elsewhere in the body. This paper describes a method for using DiR dye to label and track C17.2 neural progenitor cells to a murine model of mammary carcinoma.

Na+/K+ ATPase-targeted delivery to metastatic breast cancer models

In this study, we reported doxorubicin (DOX)-encapsulated nanoparticles (NPs) formulated with biocompatible and biodegradable poly (lactic-co-glycolic acid) (PLGA) and modified with a 13-amino acid peptide (S3) against sodium/potassium (Na⁺/K⁺)-ATPase pump alpha subunit to investigate its potential as antitumor agent. The morphological properties and size dispersity of the prepared nanoparticles were evaluated using scanning electron microscope (SEM) and dynamic light scattering (DLS). The encapsulation efficiency and in vitro release during 7 days were evaluated. Comparative in vitro cytotoxicity experiments demonstrated that the S3-conjugated nanoparticles (S3-PLGA-DOX NPs) had higher antiproliferative activity. Flow cytometry analysis confirmed the enhanced cellular uptake of S3-PLGA-DOX NPs in comparison with PLGA-DOX. In vivo study in 4T1 tumor-bearing BALB/C mice revealed that the S3-functionalized DOX-loaded NPs improved antitumor activity and survival rate of 4T1 tumor bearing mice. In this regard, conjugation of S3 peptide to the surface of DOX-loaded PLGA NPs provides site-specific delivery of DOX, inhibits 4T1 tumor growth in vivo and significantly decreases systemic toxicity. The obtained results suggested that the new (Na⁺/K⁺)-ATPase pump-targeted PLGA NPs as a target-selective delivery system for DOX has great potential for the treatment of breast cancer.

Adenovirus and Oxaliplatin cooperate as agnostic sensitizers for immunogenic cell death in colorectal carcinoma

Treatments with cytotoxic agents or viruses may cause Immunogenic Cell Death (ICD) that immunize tumor-bearing hosts but do not cause complete regression of tumor. We postulate that combining two ICD inducers may cause durable regression in immunocompetent mice. ICD was optimized in vitro by maximizing calreticulin externalization in human colorectal carcinoma (CRC) cells by exposure to mixtures of Oxaliplatin (OX) and human adenovirus (AdV). Six mm diameter CT26 or 4T1 carcinomas in flanks of BALB/c mice were injected once intratumorally (IT) with OX, AdV or their mixture. Tumor growth, Tumor-Infiltrating Lymphocytes (TIL), nodal cytotoxicity, and rejection of a viable cell challenge were measured. Tumors injected IT once with an optimum mixture of 80 µM OX - AdV 25 Multiplicity of Infection (MOI) in PBS buffer were 17-29% the volume of control tumors. When buffer was changed from PBS to 5% dextrose in water (D5W), volumes of tumors injected IT with 80 µM OX-AdV 25 MOI were 10% while IT OX or AdV alone were 32% and 40% the volume of IT buffer-treated tumors. OX-AdV IT increased CD3+ TIL by 4-fold, decreased CD8+ PD-1+ TIL from 79% to 19% and induced cytotoxicity to CT26 cells in draining node lymphocytes while lymphocytes from CT26-bearing untreated mice were not cytotoxic. OX-AdV IT in D5W caused complete regression in 40% of mice. Long-term survivors rejected a contralateral challenge of CT26. The buffer for Oxaliplatin is critical. The two ICD inducer mixture is promising as an agnostic sensitizer for carcinomas like colorectal carcinoma.

Cytosolic Phospholipase A2 Alpha Regulates TLR Signaling and Migration in Metastatic 4T1 Cells

Metastatic disease is the leading cause of death in breast cancer patients. Disrupting the cancer cell’s ability to migrate may be a strategy for hindering metastasis. Cytosolic phospholipase A2 α (cPLA2α), along with downstream proinflammatory and promigratory metabolites, has been implicated in several aspects of tumorigenesis, as well as metastasis, in various types of cancer. In this study, we aim to characterize the response to reduced cPLA2α activity in metastatic versus non-metastatic cells. We employ an isogenic murine cell line pair displaying metastatic (4T1) and non-metastatic (67NR) phenotype to investigate the role of cPLA2α on migration. Furthermore, we elucidate the effect of reduced cPLA2α activity on global gene expression in the metastatic cell line. Enzyme inhibition is achieved by using a competitive pharmacological inhibitor, cPLA2α inhibitor X (CIX). Our data show that 4T1 expresses significantly higher cPLA2α levels as compared to 67NR, and the two cell lines show different sensitivity to the CIX treatment with regards to metabolism and proliferation. Inhibition of cPLA2α at nontoxic concentrations attenuates migration of highly metastatic 4T1 cells, but not non-metastatic 67NR cells. Gene expression analysis indicates that processes such as interferon type I (IFN-I) signaling and cell cycle regulation are key processes regulated by cPLA2a in metastatic 4T1 cells, supporting the findings from the biological assays. This study demonstrates that two isogenic cancer cell lines with different metastatic potential respond differently to reduced cPLA2α activity. In conclusion, we argue that cPLA2α is a potential therapeutic target in cancer and that enzyme inhibition may inhibit metastasis through an anti-migratory mechanism, possibly involving Toll-like receptor signaling and type I interferons.

Targeting myeloid-derived suppressor cells in combination with primary mammary tumor resection reduces metastatic growth in the lungs

BACKGROUND

Solid tumors produce proteins that can induce the accumulation of bone marrow-derived cells in various tissues, and these cells can enhance metastatic tumor growth by several mechanisms. 4T1 murine mammary tumors are known to produce granulocyte colony-stimulating factor (G-CSF) and increase the numbers of immunosuppressive CD11b⁺Gr1⁺ myeloid-derived suppressor cells (MDSCs) in tissues such as the spleen and lungs of tumor-bearing mice. While surgical resection of primary tumors decreases MDSC levels in the spleen, the longevity and impact of MDSCs and other immune cells in the lungs after tumor resection have been less studied.

METHODS

We used mass cytometry time of flight (CyTOF) and flow cytometry to quantify MDSCs in the spleen, peripheral blood, and lungs of mice bearing orthotopic murine mammary tumors. We also tested the effect of primary tumor resection and/or gemcitabine treatment on the levels of MDSCs, other immune suppressor and effector cells, and metastatic tumor cells in the lungs.

RESULTS

We have found that, similar to mice with 4T1 tumors, mice bearing metastatic 4T07 tumors also exhibit accumulation of CD11b⁺Gr1⁺ MDSCs in the spleen and lungs, while tissues of mice with non-metastatic 67NR tumors do not contain MDSCs. Mice with orthotopically implanted 4T1 tumors have increased granulocytic (G-) MDSCs, monocytic (M-) MDSCs, macrophages, eosinophils, and NK cells in the lungs. Resection of primary 4T1 tumors decreases G-MDSCs, M-MDSCs, and macrophages in the lungs within 48 h, but significant numbers of functional immunosuppressive G-MDSCs persist in the lungs for 2 weeks after tumor resection, indicative of an environment that can promote metastatic tumor growth. The chemotherapeutic agent gemcitabine depletes G-MDSCs, M-MDSCs, macrophages, and eosinophils in the lungs of 4T1 tumor-bearing mice, and we found that treating mice with gemcitabine after primary tumor resection decreases residual G-MDSCs in the lungs and decreases subsequent metastatic growth.

CONCLUSIONS

Our data support the development of therapeutic strategies to target MDSCs and to monitor MDSC levels before and after primary tumor resection to enhance the effectiveness of immune-based therapies and improve the treatment of metastatic breast cancer in the clinic.

PiggyBac-modified CD19-expressing 4T1 cell line for the evaluation of CAR construct

Reliable and stable target cell lines are required for evaluating the efficiency and studying the mechanism of chimeric antigen receptor T (CAR-T) immunotherapy both in vitro and in vivo. Jurkat cells can be used as an alternative for human primary lymphocytes to evaluate the constructs and function of the "CAR". This study established a murine 4T1-CD19 cell line that stably expressed a cd19 gene. The 4T1-CD19 cells had similar growth kinetics to its parent cell 4T1. The protein CD19 expression of the 4T1-CD19 was detected by reverse transcription-polymerase chain reaction (RT-PCR) and western blot. The second-generation CAR was constructed and transfected into Jurkat cells. The expression of CAR protein was analyzed by flow cytometry and western blot. Finally, the interaction between the CAR and CD19 was confirmed by the upregulation of the IL-2 mRNA level of Jurkat-CAR stimulated by 4T1-CD19. Therefore, the 4T1-CD19 cell line and Jurkat-CAR have been successfully established, and may be used to access the function of various CAR constructs both in vitro and in vivo.

Evaluation of the Radiosensitizing Potency of Bromelain for Radiation Therapy of 4T1 Breast Cancer Cells

Breast cancer (BC) remains the leading cause of death in women worldwide, despite the improvements of cancer screening and treatment methods. Recently, development of novel anticancer drugs for the improved prevention and treatment of BC is in the center of research. The anticancer effects of bromelain, as enzyme extract derived from the pineapples, contains chemicals that interfere with the growth of tumor cells. The aim of this study was to evaluate the effect of radiosensitizing of bromelain in 4T1 BC cells. This investigation utilized the 3-(4,5-dimethylthiazol-2-yl)-2,5-dimethyltetrazolium bromide assay to characterize the cytotoxicity of bromelain. Colony formation method was used to establish the truth of the capability of bromelain to make sensitive to radiation therapy. Flowcytometry performed to define the contribution the apoptosis effect to bromelain mediated radiosensitization of 4T1 cells. Bromelain reduced growth and proliferation of 4T1 cell as a concentration-dependence manner significantly. The survival of 4T1 cancer cells was decreased after combined treatment in a number and size-dependent manner with regard to the control group (P < 0.05). Combination of bromelain with radiation does not influence 4T1 cell apoptosis. The results suggested that bromelain can inhibit the growth and proliferation and reduce survival of 4T1 BC cells and might be used as a candidate radiosensitizer in BC patient.

Strobilanthes crispus inhibits migration, invasion and metastasis in breast cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Strobilanthes crispus (L.) Blume, locally known in Malaysia as "Pecah kaca" or "Jin batu", has been traditionally used for treatment of various ailments including cancer. We previously demonstrated that a standardized bioactive subfraction of S. crispus, termed as F3, possessed potent anticancer effects in both in vitro and in vivo breast cancer models.

AIM OF THE STUDY

To investigate the potential of F3 from S. crispus to prevent metastasis in breast cancer.

MATERIALS AND METHODS

The antimetastatic effects of F3 were first investigated on murine 4T1 and human MDA-MB-231 breast cancer cell (BCC) lines using cell proliferation, wound healing and invasion assays. A 4T1-induced mouse mammary carcinoma model was then used to determine the expression of metastasis tumor markers, epithelial (E)-cadherin, matrix metalloproteinase (MMP)-9, mucin (MUC)-1, nonepithelial (N)-cadherin, Twist, vascular endothelial growth factor (VEGF) and vimentin, using immunohistochemistry, following oral treatment with F3 for 30 days.

RESULTS

Significant growth arrest was observed with F3 IC₅₀ values of 84.27 µg/ml (24 h) and 74.41 µg/ml (48 h) for MDA-MB-231, and 87.35 µg/ml (24 h) and 78.75 µg/ml (48 h) for 4T1 cells. F3 significantly inhibited migration of both BCC lines at 50 μg/ml for 24 h (p = 0.018 and p = 0.015, respectively). Similarly, significant inhibition of invasion was demonstrated in 4T1 (75 µg/ml, p = 0.016) and MDA-MB-231 (50 µg/ml, p = 0.040) cells compared to the untreated cultures. F3 treatment resulted in reduced tumor growth compared to untreated mice (p < 0.01) or mice treated with tamoxifen (p < 0.05). Statistical parameters (absolute count, proportion, intensity and overall scores) indicating upregulation of E-cadherin expression were statistically significant in F3-treated compared to the untreated tumor-bearing mice. Similarly, F3 significantly reduced the expression of MMP-9, MUC1, N-cadherin, Twist, VEGF and vimentin in comparison with the TM (p < 0.01) group CONCLUSIONS: Our findings suggest that F3 exerts anti-metastatic effects independent of its cytotoxic effects, and these are supported by the increased expression of E-cadherin concurrent with downregulation of MMP-9, MUC1, N-cadherin, Twist, VEGF and vimentin expression in breast cancer.

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.

Brain permeant and impermeant inhibitors of fatty-acid amide hydrolase suppress the development and maintenance of paclitaxel-induced neuropathic pain without producing tolerance or physical dependence in vivo and synergize with paclitaxel to reduce tumor cell line viability in vitro

Activation of cannabinoid CB₁ receptors suppresses pathological pain but also produces unwanted side effects, including tolerance and physical dependence. Inhibition of fatty-acid amide hydrolase (FAAH), the major enzyme catalyzing the degradation of anandamide (AEA), an endocannabinoid, and other fatty-acid amides, suppresses pain without unwanted side effects typical of direct CB₁ agonists. However, FAAH inhibitors have failed to show efficacy in several clinical trials suggesting that the right partnership of FAAH inhibition and pathology has yet to be identified. We compared efficacy of chronic treatments with a centrally penetrant FAAH inhibitor (URB597), a peripherally restricted FAAH inhibitor (URB937) and an orthosteric pan-cannabinoid agonist (WIN55,212-2) in suppressing neuropathic pain induced by the chemotherapeutic agent paclitaxel. Each FAAH inhibitor suppressed the development of paclitaxel-induced neuropathic pain and reduced the maintenance of already established allodynia with sustained efficacy. Tolerance developed to the anti-allodynic efficacy of WIN55,212-2, but not to that of URB597 or URB937, in each dosing paradigm. Challenge with the CB₁ antagonist rimonabant precipitated CB₁-dependent withdrawal in paclitaxel-treated mice receiving WIN55,212-2 but not URB597 or URB937. When dosing with either URB597 or URB937 was restricted to the development of neuropathy, paclitaxel-induced allodynia emerged following termination of drug delivery. These observations suggest that both FAAH inhibitors were anti-allodynic rather than curative. Moreover, neither URB597 nor URB937 impeded the ability of paclitaxel to reduce breast (4T1) or ovarian (HeyA8) tumor cell line viability. In fact, URB597 and URB937 alone reduced 4T1 tumor cell line viability, albeit with low potency, and the dose matrix of each combination with paclitaxel was synergistic in reducing 4T1 and HeyA8 tumor cell line viability according to Bliss, Highest Single Agent (HSA) and Loewe additivity models. Both FAAH inhibitors synergized with paclitaxel to reduce 4T1 and HeyA8 tumor cell line viability without reducing viability of non-tumor HEK293 cells. Neither FAAH inhibitor reduced viability of non-tumor HEK293 cells in either the presence or absence of paclitaxel, suggesting that nonspecific cytotoxic effects were not produced by the same treatments. Our results suggest that FAAH inhibitors reduce paclitaxel-induced allodynia without the occurrence of CB₁-dependence in vivo and may, in fact, enhance the anti-tumor actions of paclitaxel in vitro.

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.

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.