scholarly journals Deciphering the temporal heterogeneity of cancer-associated fibroblast subpopulations in breast cancer

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Freja Albjerg Venning ◽  
Kamilla Westarp Zornhagen ◽  
Lena Wullkopf ◽  
Jonas Sjölund ◽  
Carmen Rodriguez-Cupello ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Flow Cytometry ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Ex Vivo ◽  
Smooth Muscle Actin ◽  
Mammary Tissue ◽  
Temporal Heterogeneity ◽  
Alpha Smooth Muscle Actin ◽  
Murine Tumours

Abstract Background Cancer-associated fibroblasts (CAFs) comprise a heterogeneous population of stromal cells within the tumour microenvironment. CAFs exhibit both tumour-promoting and tumour-suppressing functions, making them exciting targets for improving cancer treatments. Careful isolation, identification, and characterisation of CAF heterogeneity is thus necessary for ex vivo validation and future implementation of CAF-targeted strategies in cancer. Methods Murine 4T1 (metastatic) and 4T07 (poorly/non-metastatic) orthotopic triple negative breast cancer tumours were collected after 7, 14, or 21 days. The tumours were analysed via flow cytometry for the simultaneous expression of six CAF markers: alpha smooth muscle actin (αSMA), fibroblast activation protein alpha (FAPα), platelet derived growth factor receptor alpha and beta (PDGFRα and PDGFRβ), CD26/DPP4 and podoplanin (PDPN). All non-CAFs were excluded from the analysis using a lineage marker cocktail (CD24, CD31, CD45, CD49f, EpCAM, LYVE-1, and TER-119). In total 128 murine tumours and 12 healthy mammary fat pads were analysed. Results We have developed a multicolour flow cytometry strategy based on exclusion of non-CAFs and successfully employed this to explore the temporal heterogeneity of freshly isolated CAFs in the 4T1 and 4T07 mouse models of triple-negative breast cancer. Analysing 128 murine tumours, we identified 5–6 main CAF populations and numerous minor ones based on the analysis of αSMA, FAPα, PDGFRα, PDGFRβ, CD26, and PDPN. All markers showed temporal changes with a distinct switch from primarily PDGFRα+ fibroblasts in healthy mammary tissue to predominantly PDGFRβ+ CAFs in tumours. CD26+ CAFs emerged as a large novel subpopulation, only matched by FAPα+ CAFs in abundance. Conclusion We demonstrate that multiple subpopulations of CAFs co-exist in murine triple negative breast cancer, and that the abundance and dynamics for each marker differ depending on tumour type and time. Our results form the foundation needed to isolate and characterise specific CAF populations, and ultimately provide an opportunity to therapeutically target specific CAF subpopulations.

scholarly journals Optimizing cisplatin delivery to triple-negative breast cancer through novel EGFR aptamer-conjugated polymeric nanovectors

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Lisa Agnello ◽  
Silvia Tortorella ◽  
Annachiara d’Argenio ◽  
Clarissa Carbone ◽  
Simona Camorani ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Tumor Targeting ◽  
Triple Negative ◽  
Ex Vivo ◽  
Treatment Options ◽  
Negative Control ◽  
Therapeutic Effects ◽  
Metastatic Setting

Abstract Background Management of triple-negative breast cancer (TNBC) is still challenging because of its aggressive clinical behavior and limited targeted treatment options. Cisplatin represents a promising chemotherapeutic compound in neoadjuvant approaches and in the metastatic setting, but its use is limited by scarce bioavailability, severe systemic side effects and drug resistance. Novel site-directed aptamer-based nanotherapeutics have the potential to overcome obstacles of chemotherapy. In this study we investigated the tumor targeting and the anti-tumorigenic effectiveness of novel cisplatin-loaded and aptamer-decorated nanosystems in TNBC. Methods Nanotechnological procedures were applied to entrap cisplatin at high efficacy into polymeric nanoparticles (PNPs) that were conjugated on their surface with the epidermal growth factor receptor (EGFR) selective and cell-internalizing CL4 aptamer to improve targeted therapy. Internalization into TNBC MDA-MB-231 and BT-549 cells of aptamer-decorated PNPs, loaded with BODIPY505-515, was monitored by confocal microscopy using EGFR-depleted cells as negative control. Tumor targeting and biodistribution was evaluated by fluorescence reflectance imaging upon intravenously injection of Cyanine7-labeled nanovectors in nude mice bearing subcutaneous MDA-MB-231 tumors. Cytotoxicity of cisplatin-loaded PNPs toward TNBC cells was evaluated by MTT assay and the antitumor effect was assessed by tumor growth experiments in vivo and ex vivo analyses. Results We demonstrate specific, high and rapid uptake into EGFR-positive TNBC cells of CL4-conjugated fluorescent PNPs which, when loaded with cisplatin, resulted considerably more cytotoxic than the free drug and nanovectors either unconjugated or conjugated with a scrambled aptamer. Importantly, animal studies showed that the CL4-equipped PNPs achieve significantly higher tumor targeting efficiency and enhanced therapeutic effects, without any signs of systemic toxicity, compared with free cisplatin and untargeted PNPs. Conclusions Our study proposes novel and safe drug-loaded targeted nanosystems for EGFR-positive TNBC with excellent potential for the application in cancer diagnosis and therapy.

scholarly journals Substance P Antagonism as a Novel Therapeutic Option to Enhance Efficacy of Cisplatin in Triple Negative Breast Cancer and Protect PC12 Cells against Cisplatin-Induced Oxidative Stress and Apoptosis

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3871
Author(s):  
Emma Rodriguez ◽  
Guangsheng Pei ◽  
Sang T. Kim ◽  
Alexis German ◽  
Prema Robinson
Keyword(s):  
Breast Cancer ◽  
Flow Cytometry ◽  
Cell Line ◽  
Pc12 Cells ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Therapeutic Option ◽  
Neuronal Cell ◽  
Receptor Antagonism ◽  
Tnbc Cell

Although cisplatin is very effective as a treatment strategy in triple-negative breast cancer (TNBC), it has unwarranted outcomes owing to recurrence, chemoresistance and neurotoxicity. There is critically important to find new, effective and safe therapeutics for TNBC. We determined if SP-receptor antagonism in combination with cisplatin may serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC. We used a neuronal cell line (PC12) and two TNBC cell lines (Sum 185 and Sum 159) for these studies. We determined that the levels of cells expressing the high-affinity SP-receptor (neurokinin 1 receptor (NK1R)), as determined by flow-cytometry was significantly elevated in response to cisplatin in all three cells. We determined that treatment with aprepitant, an SP-receptor antagonist decreased cisplatin-induced, loss of viability (studied by MTT assay), production of reactive oxygen species (by DCFDA assay) and apoptosis (by flow-cytometry) in PC12 cells while it was increased in the two TNBC cells. Furthermore, we demonstrated that important genes associated with metastases, inflammation, chemoresistance and cell cycle progression are attenuated by SP-receptor antagonism in the TNBC cell line, Sum 185. These studies implicate that SP-receptor antagonism in combination with cisplatin may possibly serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC.

scholarly journals 614 Investigating immune mediated mechanisms of PARPi resistance in BRCA1-associated triple negative breast cancer (TNBC)

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A644-A644
Author(s):  
Anita Mehta ◽  
Madeline Townsend ◽  
Madisson Oliwa ◽  
Patrice Lee ◽  
Nicholas Saccomano ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Flow Cytometry ◽  
Immune Response ◽  
T Cell ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Parp Inhibitor ◽  
Triple Combination ◽  
Tumor Clearance ◽  
Sting Pathway

BackgroundPoly(ADP-ribose) polymerase inhibitors (PARPi) have improved the outcomes of BRCA-associated breast cancer; however, treatment responses are often not durable. Our preclinical studies demonstrated that PARPi activates the cGAS/STING pathway and recruitment of anti-tumor CD8+ T-cells that are required for tumor clearance [1]. These studies contributed to development of clinical trials testing PARPi plus immune checkpoint blockade (ICB). Unfortunately, early phase trials of PARPi + ICB have not yet suggested efficacy will be superior to PARPi monotherapy. Lack of demonstrated clinical synergy between PARPi + ICB underscores the need to study the tumor microenvironment (TME) during PARPi therapy to identify optimal strategies to enhance T-cell activation. We recently showed that PARPi induces CSF-1R+ suppressive tumor associated macrophages (TAMs) that restrict antitumor immune responses, contributing to PARPi resistance [2]. Removing TAMs with anti-CSF-1R therapy in combination with PARPi significantly enhanced overall survival (OS) compared to PARPi monotherapy in preclinical models [2]. Here, we investigate how modulating TAMs can enhance PARPi + ICB.MethodsMice bearing BRCA1-deficient TNBC (K14-Cre;Brca1f/f;p53f/f) tumors were treated for 98 days with PARPi (Talazoparib) ± small molecule inhibitor of CSF-1R (ARRAY-382; CSF-1Ri) ± anti-PD-1 and then followed for survival. Flow cytometry was employed to elucidate changes in the TME after treatment.ResultsPARPi conferred a significant survival advantage over vehicle treated mice (median OS 33 v. 14 days; p=0.0034) and 2/8 PARPi-treated mice experienced complete tumor clearance at day 98. PARPi + CSF-1Ri treated mice (median OS 140 days) remarkably cleared 7/10 tumors by day 98. The addition of anti-PD-1 to PARPi did not enhance OS compared to PARPi monotherapy. The triple combination of anti-PD-1 + PARPi + CSF-1Ri has not yet significantly enhanced the median OS compared to PARPi + CSF-1Ri (ongoing; 168 v. 140 days); nor did it increase clearance of tumor by day 98 (7/10). However, the triple combination led to superior long term tumor clearance. At day 161 the triple combination exhibited 5/10 tumor free mice compared to 2/10 treated with PARPi + CSF-1Ri. To elucidate how CSR-1Ri enhanced PARPi + ICB responses, flow cytometry was performed and revealed increased expression of the co-stimulatory molecule CD80, reduced tissue resident macrophages (CX3CR1+) and lower CSF-1R expression compared to PARPi + ICB.ConclusionsThese data suggest that targeting immunosuppressive macrophages may induce a favorable anti-tumor immune response and enhance responses to PARPi plus ICB. We are currently evaluating the adaptive immune response in this context.ReferencesPantelidou, C., et al., PARP inhibitor efficacy depends on CD8+ T cell recruitment via intratumoral STING pathway activation in BRCA-deficient models of triple-negative breast cancer. Cancer Discovery, 2019: p. CD-18-1218.Mehta, A.K., et al., Targeting immunosuppressive macrophages overcomes PARP inhibitor resistance in BRCA1-associated triple-negative breast cancer. Nat Cancer, 2021. 2(1): p. 66–82.

scholarly journals Targeting of prostate-specific membrane antigen for radio-ligand therapy of triple-negative breast cancer

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Agnieszka Morgenroth ◽  
Ebru Tinkir ◽  
Andreas T. J. Vogg ◽  
Ramya Ambur Sankaranarayanan ◽  
Fatima Baazaoui ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Triple Negative Breast Cancer ◽  
Breast Cancer Cells ◽  
Triple Negative ◽  
Ex Vivo ◽  
Tube Formation ◽  
Huvec Cells ◽  
Specific Membrane

Abstract Background Triple-negative breast cancer has extremely high risk of relapse due to the lack of targeted therapies, intra- and inter-tumoral heterogeneity, and the inherent and acquired resistance to therapies. In this study, we evaluate the potential of prostate-specific membrane antigen (PSMA) as target for radio-ligand therapy (RLT). Methods Tube formation was investigated after incubation of endothelial HUVEC cells in tumor-conditioned media and monitored after staining using microscopy. A binding study with 68Ga-labeled PSMA-addressing ligand was used to indicate targeting potential of PSMA on tumor-conditioned HUVEC cells. For mimicking of the therapeutic application, tube formation potential and vitality of tumor-conditioned HUVEC cells were assessed following an incubation with radiolabeled PSMA-addressing ligand [177Lu]-PSMA-617. For in vivo experiments, NUDE mice were xenografted with triple-negative breast cancer cells MDA-MB231 or estrogen receptor expressing breast cancer cells MCF-7. Biodistribution and binding behavior of [68Ga]-PSMA-11 was investigated in both tumor models at 30 min post injection using μPET. PSMA- and CD31-specific staining was conducted to visualize PSMA expression and neovascularization in tumor tissue ex vivo. Results The triple-negative breast cancer cells MDA-MB231 showed a high pro-angiogenetic potential on tube formation of endothelial HUVEC cells. The induced endothelial expression of PSMA was efficiently addressed by radiolabeled PSMA-specific ligands. 177Lu-labeled PSMA-617 strongly impaired the vitality and angiogenic potential of HUVEC cells. In vivo, as visualized by μPET, radiolabeled PSMA-ligand accumulated specifically in the triple-negative breast cancer xenograft MDA-MB231 (T/B ratio of 43.3 ± 0.9), while no [68Ga]-PSMA-11 was detected in the estrogen-sensitive MCF-7 xenograft (T/B ratio of 1.1 ± 0.1). An ex vivo immunofluorescence analysis confirmed the localization of PSMA on MDA-MB231 xenograft-associated endothelial cells and also on TNBC cells. Conclusions Here we demonstrate PSMA as promising target for two-compartment endogenous radio-ligand therapy of triple-negative breast cancer.

scholarly journals Neoantigen DNA vaccines are safe, feasible, and capable of inducing neoantigen-specific immune responses in patients with triple negative breast cancer

2021 ◽  
Author(s):  
Xiuli Zhang ◽  
S. Peter Goedegebuure ◽  
Nancy Myers ◽  
Tammy Vickery ◽  
Michael McLellan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Flow Cytometry ◽  
Immune Responses ◽  
Dna Vaccine ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Dna Vaccines ◽  
Laboratory Evaluation ◽  
Minimal Risk ◽  
Free Survival

PURPOSE: Cancer neoantigens are important targets of cancer immunotherapy. Neoantigen vaccines have the potential to induce or enhance highly specific antitumor immune responses with minimal risk of autoimmunity. We have developed a neoantigen DNA vaccine platform capable of efficiently presenting both HLA class I and II epitopes. To test the safety, feasibility and efficacy of this platform, we performed a phase 1 clinical trial in triple negative breast cancer patients with persistent disease following neoadjuvant chemotherapy, a patient population at high risk of disease recurrence. EXPERIMENTAL DESIGN: Expressed somatic mutations were identified by tumor/normal exome sequencing and tumor RNA sequencing. The pVACtools software suite was used to identify and prioritize cancer neoantigens. Neoantigen DNA vaccines were designed and manufactured in an academic GMP facility at Washington University School of Medicine. Neoantigen DNA vaccines were administered via electroporation following completion of standard of care therapy. Safety was measured by clinical and laboratory evaluation. Immune responses were assessed by ELISPOT, flow cytometry and TCR sequencing. RESULTS: 18 subjects received three doses of a personalized neoantigen DNA vaccine encoding on average 11 neoantigens per patient (range 4-20). The vaccinations were well tolerated with limited adverse events, primarily related to injection site reactions. Neoantigen-specific immune responses were induced in 16/18 patients as measured by ELISPOT and flow cytometry. At a median follow-up of 36 months, progression-free survival was 87.5% (95% CI: 72.7-100%) in the cohort of vaccinated patients compared to 49% (95% CI: 36.4-65.9%) in a cohort of institutional historical control patients (p=0.011). CONCLUSIONS: Neoantigen DNA vaccines are safe, feasible, and capable of inducing a neoantigen-specific immune response. There is preliminary evidence of improved disease-free survival compared to historical controls.

scholarly journals Deciphering the temporal heterogeneity of cancer-associated fibroblast subpopulations in breast cancer

2020 ◽  
Author(s):  
Freja Albjerg Venning ◽  
Kamilla Westarp Zornhagen ◽  
Lena Wullkopf ◽  
Morteza Chalabi Hajkarim ◽  
Kyoung Jae Won ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Smooth Muscle Actin ◽  
Growth Factor Receptor ◽  
Tumour Microenvironment ◽  
Temporal Heterogeneity ◽  
Alpha Smooth Muscle Actin ◽  
Cancer Treatments ◽  
Cancer Associated Fibroblast ◽  
Factor Receptor Alpha ◽  
Fibroblast Activation Protein Alpha

AbstractCancer-associated fibroblasts (CAFs) comprise a heterogeneous population of stromal cells within the tumour microenvironment. CAFs exhibit both tumour-promoting and tumour-suppressing functions, making them exciting targets for improving cancer treatments. A careful identification and characterisation of the CAF heterogeneity is thus necessary before implementing CAF-targeted strategies in cancer. With that in mind, we developed a flow cytometry strategy based on exclusion of non-CAF cells and successfully employed it to explore the temporal heterogeneity of CAFs in two models of triple-negative breast cancer (4T1 and 4T07). Analysing 128 murine tumours we identified 5-6 main CAF subpopulations and numerous minor ones based on the analysis of alpha smooth muscle actin, fibroblast activation protein alpha, platelet derived growth factor receptor alpha and beta, CD26/DPP4 and podoplanin. All markers showed temporal changes, and CD26+ CAFs emerged as a large novel subpopulation. These results form the foundation needed for the future elucidation of tumour-promoting CAF subpopulations.

scholarly journals Aptamer targeted therapy potentiates immune checkpoint blockade in triple-negative breast cancer

2020 ◽  
Author(s):  
Simona Camorani ◽  
Margherita Passariello ◽  
Lisa Agnello ◽  
Silvia Esposito ◽  
Francesca Collina ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Triple Negative Breast Cancer ◽  
Immune Checkpoint ◽  
Triple Negative ◽  
Lung Metastases ◽  
Ex Vivo ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade

Abstract Background: Triple-negative breast cancer (TNBC) is a uniquely aggressive cancer with high rates of relapse due to resistance to chemotherapy. TNBC expresses higher levels of programmed cell death-ligand 1 (PD-L1) compared to other breast cancers, providing the rationale for the recently approved immunotherapy with anti-PD-L1 monoclonal antibodies (mAbs). A huge effort is dedicated to identify actionable biomarkers allowing for combination therapies with immune-checkpoint blockade. Platelet-derived growth factor receptor β (PDGFRβ) is highly expressed in invasive TNBC, both on tumor cells and tumor microenvironment. We recently proved that tumor growth and lung metastases are impaired in mouse models of human TNBC by a high efficacious PDGFRβ aptamer. Hence, we aimed at investigating the effectiveness of a novel combination treatment with the PDGFRβ aptamer and anti-PD-L1 mAbs in TNBC.Methods: The targeting ability of the anti-human PDGFRβ aptamer toward the murine receptor was verified by streptavidin-biotin assays and confocal microscopy, and its inhibitory function by transwell migration assays. The anti-proliferative effects of the PDGFRβ aptamer/anti-PD-L1 mAbs combination was assessed in human MDA-MB-231 and murine 4T1 TNBC cells, both grown as monolayer or co-cultured with lymphocytes. Tumor cell lysis and cytokines secretion by lymphocytes were analyzed by LDH quantification and ELISA, respectively. Orthotopic 4T1 xenografts in syngeneic mice were used for dissecting the effect of aptamer/mAb combination on tumor growth, metastasis and lymphocytes infiltration. Ex vivo analyses through immunohistochemistry, RT-qPCR and immunoblotting were performed. Results: We show that the PDGFRβ aptamer potentiates the anti-proliferative activity of anti-PD-L1 mAbs on both human and murine TNBC cells, according to its human/mouse cross-reactivity. Further, by binding to activated human and mouse lymphocytes, the aptamer enhances the anti-PD-L1 mAb-induced cytotoxicity of lymphocytes against tumor cells. Importantly, the aptamer heightens the antibody efficacy in inhibiting tumor growth and lung metastases in mice. It acts on both tumor cells, inhibiting Akt and ERK1/2 signaling pathways, and immune populations, increasing intratumoral CD8+T cells and reducing FOXP3+Treg cells. Conclusion: Co-treatment of PDGFRβ aptamer with anti-PD-L1 mAbs is a viable strategy, thus providing for the first an evidence of the efficacy of PDGFRβ/PD-L1 co-targeting combination therapy in TNBC.

scholarly journals Effect of tetrandrine combined with arsenic trioxide on stem cells of triple negative breast cancer

2019 ◽  
Author(s):  
Yubo Guo ◽  
Yingyi Fan ◽  
Ruixian Wu ◽  
Xiaohua Pei
Keyword(s):  
Breast Cancer ◽  
Stem Cells ◽  
Flow Cytometry ◽  
Stem Cell ◽  
Arsenic Trioxide ◽  
Triple Negative Breast Cancer ◽  
Cancer Metastasis ◽  
Triple Negative ◽  
Breast Cancer Metastasis ◽  
Blue Staining

Abstract Background Although the triple negative breast cancer is sensitive to chemotherapy, breast cancer stem cells (BCSCs) is the origin of tumor chemotherapy resistance, tumor recurrence and tumor invasion and metastasis. This study aims to examine the effect of tetrandrine combine with arsenic trioxide on BCSCs and potential mechanism of anti- triple negative breast cancer metastasis. Methods We cultured the triple negative breast cancer cell MDA-MB-231 and induced BCSCs sphere formation by serum-free medium for 5 days. In the MDA-MB-231 cell and MDA-MB-231 stem cell, we compared the ratio of CD44+/CD24- and sorted stem cells by flow cytometry, the expression of Oct4 and Sox2mRNA were by rt-PCR, invasion ability were by Transwell assay. We subsequently measured the effect of tetrandrine combine with arsenic trioxide on BCSCs proliferation by CCK8 method. The stem cell morphology observation was by trypan blue staining. Stem cell cycle and apoptosis were evaluated by flow cytometry. Western Blot was used to measure the protein levels of Hedgehog, Notch1 and PTEN signaling of BCSCs. Results The ratio of CD44+/CD24- in MDA-MB-231 stem cells was 95.0%, while MDA-MB-231 cell was 89.3%. The invasion number of MDA-MB-231 stem cell was significantly higher than that of MDA-MB-231 cells (p<0.01). Furthermore, we demonstrated that tetrandrine and arsenic trioxide could inhibit the BCSCs proliferation. Tetrandrine combine with arsenic trioxide could significantly promote the apoptosis (p<0.01) and increase the percentage of G0/G1 phase and decrease the G2/M phase (p<0.01) of BCSCs. Compared with the control group, arsenic trioxide, tetrandrine and the combined group could significantly reduce the expression of GLI1 and SMO and increase the expression of PTEN protein (P<0.05). Conclusions These findings revealed that tetrandrine combined with arsenic trioxide could suppress the proliferation and induce apoptosis of BCSCs by decreased Gli and SMO expression and increased PTEN expression. Targeting BCSCs treatment, this study provides potential therapeutic drugs against triple negative breast cancer metastasis.

scholarly journals Lung-Derived Selectins Enhance Metastatic Behavior of Triple Negative Breast Cancer Cells

Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1580
Author(s):  
Sami U. Khan ◽  
Ying Xia ◽  
David Goodale ◽  
Gabriella Schoettle ◽  
Alison L. Allan
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Therapeutic Target ◽  
Triple Negative ◽  
Ex Vivo ◽  
Metastatic Progression ◽  
Wild Type ◽  
Potential Therapeutic Target ◽  
Metastatic Behavior

The lung is one of the deadliest sites of breast cancer metastasis, particularly for triple negative breast cancer (TNBC). We have previously shown that the lung produces several soluble factors that may enhance the metastatic behavior of TNBC, including E-, L-, and P-selectin. In this paper, we hypothesize that lung-derived selectins promote TNBC metastatic behavior and may serve as a potential therapeutic target. Lungs were isolated from mice and used to generate lung-conditioned media (CM). Lung-derived selectins were immunodepleted and TNBC migration and proliferation were assessed in response to native or selectin-depleted lung-CM. A 3D ex vivo pulmonary metastasis assay (PuMA) was used to assess the metastatic progression of TNBC in the lungs of wild-type versus triple-selectin (ELP-/-) knockout mice. We observed that individual lung-derived selectins enhance in vitro migration (p ≤ 0.05), but not the proliferation of TNBC cells, and that ex vivo metastatic progression is reduced in the lungs of ELP-/- mice compared to wild-type mice (p ≤ 0.05). Treatment with the pan-selectin inhibitor bimosiamose reduced in vitro lung-specific TNBC migration and proliferation (p ≤ 0.05). Taken together, these results suggest that lung-derived selectins may present a potential therapeutic target against TNBC metastasis. Future studies are aimed at elucidating the pro-metastatic mechanisms of lung-derived selectins and developing a lung-directed therapeutic approach.

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