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.

Effects of CD44 siRNA on inhibition, survival, and apoptosis of breast cancer cell lines (MDA-MB-231 and 4T1)

BACKGROUND

Breast cancer (BC) is one of the most common cancers in the world. Despite the many advances that have been made in treating patients, many patients are still resistant to treatment. CD44 is one of the surface glycoproteins of BC cells that plays an important role in the proliferation of these cells and inhibition of their apoptosis. Therefore, targeting it can be a treatment way for BC patients.

METHODS

In this study, the effect of anti-CD44 siRNA on the proliferation, apoptosis, and migration rate of MDA-MB-231 and 4T1 cells was investigated. The techniques used in this study were MTT assay, RT-PCR, and flow cytometry.

RESULTS

The apoptosis and proliferation rates in CD44 siRNA-treated cells were higher and lower, respectively, compared to untreated cells. Also, cell migration was less in treated cells compared to untreated cells. CD44 siRNA also decreased the expression of CXCR4, c-myc, Vimentin, ROCK, and MMP-9.

CONCLUSION

Finally, CD44 targeting can be a good treatment option to make BC cells more sensitive to apoptosis.

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.