scholarly journals Exploiting off-target effects of estrogen deprivation to sensitize estrogen receptor negative breast cancer to immune killing

2021 ◽  
Vol 9 (7) ◽  
pp. e002258
Author(s):  
Benjamin Wolfson ◽  
Michelle R Padget ◽  
Jeffrey Schlom ◽  
James W Hodge
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Natural Killer ◽  
Tumor Cells ◽  
Breast Cancer Cells ◽  
Nk Cell ◽  
Cell Killing ◽  
Rna Profiling ◽  
Er Targeting

BackgroundThere are highly effective treatment strategies for estrogen receptor (ER)+, progesterone receptor (PR)+, and HER2+ breast cancers; however, there are limited targeted therapeutic strategies for the 10%–15% of women who are diagnosed with triple-negative breast cancer. Here, we hypothesize that ER targeting drugs induce phenotypic changes to sensitize breast tumor cells to immune-mediated killing regardless of their ER status.MethodsReal-time cell analysis, flow cytometry, qRT-PCR, western blotting, and multiplexed RNA profiling were performed to characterize ER+ and ER− breast cancer cells and to interrogate the phenotypic effects of ER targeting drugs. Sensitization of breast cancer cells to immune cell killing by the tamoxifen metabolite 4-hydroxytamoxifen (4-OHT) and fulvestrant was determined through in vitro health-donor natural killer cell 111IN-release killing assays. A syngeneic tumor study was performed to validate these findings in vivo.ResultsPretreatment with tamoxifen metabolite 4-OHT or fulvestrant resulted in increased natural killer (NK)–mediated cell lysis of both ER+ and ER− breast cancer cells. Through multiplexed RNA profiling analysis of 4-OHT-treated ER+ and ER− cells, we identified increased activation of apoptotic and death receptor signaling pathways and identified G protein-coupled receptor for estrogen (GPR30) engagement as a putative mechanism for immunogenic modulation. Using the specific GPR30 agonist G-1, we demonstrate that targeted activation of GPR30 signaling resulted in increased NK cell killing. Furthermore, we show that knockdown of GPR30 inhibited 4-OHT and fulvestrant mediated increases to NK cell killing, demonstrating this is dependent on GPR30 expression. Moreover, we demonstrate that this mechanism remains active in a 4-OHT-resistant MCF7 cell line, showing that even in patient populations with ER+ tumors that are resistant to the cytotoxic effects of tamoxifen, 4-OHT treatment sensitizes them to immune-mediated killing. Moreover, we find that fulvestrant pretreatment of tumor cells synergizes with the IL-15 superagonist N-803 treatment of NK cells and sensitizes tumor cells to killing by programmed death-ligand 1 (PD-L1) targeting high-affinity natural killer (t-haNK) cells. Finally, we demonstrate that the combination of fulvestrant and N-803 is effective in triple-negative breast cancer in vivo.ConclusionTogether, these findings demonstrate a novel effect of ER targeting drugs on the interaction of ER+ and, surprisingly, ER− tumors cells with the immune system. This study is the first to demonstrate the potential use of ER targeting drugs as immunomodulatory agents in an ER agnostic manner and may inform novel immunotherapy strategies in breast cancer.

750 Malat1 lncRNA controls metastatic reactivation of dormant breast cancer by immune evasion

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A799-A799
Author(s):  
Dhiraj Kumar ◽  
Sreeharsha Gurrapu ◽  
Hyunho Han ◽  
Yan Wang ◽  
Seongyeon Bae ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Single Cell ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Immune Evasion ◽  
Breast Cancer Cells ◽  
Metastatic Potential ◽  
Rna Seq

BackgroundLong non-coding RNAs (lncRNAs) are involved in various biological processes and diseases. Malat1 (metastasis-associated lung adenocarcinoma transcript 1), also known as Neat2, is one of the most abundant and highly conserved nuclear lncRNAs. Several studies have shown that the expression of lncRNA Malat1 is associated with metastasis and serving as a predictive marker for various tumor progression. Metastatic relapse often develops years after primary tumor removal as a result of disseminated tumor cells undergoing a period of latency in the target organ.1–4 However, the correlation of tumor intrinsic lncRNA in regulation of tumor dormancy and immune evasion is largely unknown.MethodsUsing an in vivo screening platform for the isolation of genetic entities involved in either dormancy or reactivation of breast cancer tumor cells, we have identified Malat1 as a positive mediator of metastatic reactivation. To functionally uncover the role of Malat1 in metastatic reactivation, we have developed a knock out (KO) model by using paired gRNA CRISPR-Cas9 deletion approach in metastatic breast and other cancer types, including lung, colon and melanoma. As proof of concept we also used inducible knockdown system under in vivo models. To delineate the immune micro-environment, we have used 10X genomics single cell RNA-seq, ChIRP-seq, multi-color flowcytometry, RNA-FISH and immunofluorescence.ResultsOur results reveal that the deletion of Malat1 abrogates the tumorigenic and metastatic potential of these tumors and supports long-term survival without affecting their ploidy, proliferation, and nuclear speckles formation. In contrast, overexpression of Malat1 leads to metastatic reactivation of dormant breast cancer cells. Moreover, the loss of Malat1 in metastatic cells induces dormancy features and inhibits cancer stemness. Our RNA-seq and ChIRP-seq data indicate that Malat1 KO downregulates several immune evasion and stemness associated genes. Strikingly, Malat1 KO cells exhibit metastatic outgrowth when injected in T cells defective mice. Our single-cell RNA-seq cluster analysis and multi-color flow cytometry data show a greater proportion of T cells and reduce Neutrophils infiltration in KO mice which indicate that the immune microenvironment playing an important role in Malat1-dependent immune evasion. Mechanistically, loss of Malat1 is associated with reduced expression of Serpinb6b, which protects the tumor cells from cytotoxic killing by the T cells. Indeed, overexpression of Serpinb6b rescued the metastatic potential of Malat1 KO cells by protecting against cytotoxic T cells.ConclusionsCollectively, our data indicate that targeting this novel cancer-cell-initiated domino effect within the immune system represents a new strategy to inhibit tumor metastatic reactivation.Trial RegistrationN/AEthics ApprovalFor all the animal studies in the present study, the study protocols were approved by the Institutional Animal Care and Use Committee(IACUC) of UT MD Anderson Cancer Center.ConsentN/AReferencesArun G, Diermeier S, Akerman M, et al., Differentiation of mammary tumors and reduction in metastasis upon Malat1 lncRNA loss. Genes Dev 2016 Jan 1;30(1):34–51.Filippo G. Giancotti, mechanisms governing metastatic dormancy and reactivation. Cell 2013 Nov 7;155(4):750–764.Gao H, Chakraborty G, Lee-Lim AP, et al., The BMP inhibitor Coco reactivates breast cancer cells at lung metastatic sites. Cell 2012b;150:764–779.Gao H, Chakraborty G, Lee-Lim AP, et al., Forward genetic screens in mice uncover mediators and suppressors of metastatic reactivation. Proc Natl Acad Sci U S A 2014 Nov 18; 111(46): 16532–16537.

Role of natural killer cells in hormone-independent rapid tumor formation and spontaneous metastasis of breast cancer cells in vivo

2006 ◽  
Vol 104 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Md. Zahidunnabi Dewan ◽  
Hiroshi Terunuma ◽  
Masahiro Takada ◽  
Yuetsu Tanaka ◽  
Hiroyuki Abe ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Natural Killer Cells ◽  
Cancer Cells ◽  
Natural Killer ◽  
Breast Cancer Cells ◽  
Tumor Formation ◽  
Spontaneous Metastasis ◽  
Killer Cells

529 Cancer cells educate natural killer cells to a metastasis promoting cell state

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A565-A565
Author(s):  
Isaac Chan ◽  
Hildur Knútsdóttir ◽  
Gayathri Ramakrishnan ◽  
Veena Padmanaban ◽  
Manisha Warrier ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Nk Cells ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Nk Cell ◽  
Ex Vivo ◽  
Tumor Bearing ◽  
Growth Promoting ◽  
Tumor Organoids

BackgroundMetastatic disease drives breast cancer mortality. We recently discovered that leading cells at the invasive edge of mammary tumor organoids retain a conserved basal epithelial program defined by their expression of keratin-14 (K14), establishing K14 as a good marker of invasive breast cancer cells. K14-positive invasive cells also exhibit characteristics that make them targets of immunosurveillance by natural killer (NK) cells. While NK cells are key immune mediators in the control of metastasis, our understanding of the specific mechanisms behind this regulation and its eventual evasion by metastatic cells remains incomplete.MethodsWe have developed a novel preclinical 3D co-culture assay to discover mechanisms behind interactions between K14+ invasive breast cancer cells and NK cells. Combined with in vivo assays of metastasis, we are able to determine how NK cells limit the early stages of metastasis and also how tumor cells can influence key NK cell properties.ResultsIn ex vivo co-culture assays of NK cells isolated from healthy mouse donors and mammary tumor organoids from MMTV-PyMT and C31T mouse models of breast cancer, we demonstrate that NK cells limit the early stages of metastasis. Antibodies to invasive K14+ cells were able to enhance the ability of NK cells to limit colony formation, suggesting antibody-dependent cell mediated cytotoxicity. Surprisingly, when isolated from tumor bearing mice, NK cells did not limit invasion and instead promoted colony formation. The in vivo adoptive transfer of NK cells from healthy donors prevents the progression of early lung metastatic seeds to macrometastases, while the adoptive transfer of cells isolated from tumor bearing donors promotes macrometastatic development. Transcriptomic analysis of reprogrammed NK cells demonstrate they have similar profiles to resting NK cells. This growth promoting phenotype can be reversed with antibodies targeting inhibitory cell surface receptors or the epigenome.ConclusionsOur ex vivo and in vivo data demonstrate that healthy donor NK cells can limit metastasis through the directed cytotoxicity against pioneering K14+ invasive cells. However, prolonged exposure to tumors reprogram NK cells from tumor killing to tumor promoting, specifically in promoting the outgrowth of macrometastases. Further, we can neutralize this effect using NK cell specific inhibitory antibodies and epigenetic modifiers. This is the first time inhibitory signaling on NK cells have been linked with a growth promoting phenotype. These data can provide insight into when the use of NK cell directed therapies can be used to treat or prevent clinically relevant metastatic disease.

The Expression of Erythropoietin and Its Receptor in Breast Cancer Is Associated with In Vivo Tumor Hypoxia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4256-4256
Author(s):  
Murat O. Arcasoy ◽  
Khalid Amin ◽  
Shu-Chuan Chou ◽  
Ruth Lininger ◽  
James A. Raleigh ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Primary Breast Cancer ◽  
Breast Cancer Cells ◽  
Significant Positive Correlation ◽  
Tumor Hypoxia ◽  
N 93 ◽  
Epor Expression

Abstract Erythropoietin (EPO) is primarily produced in the adult kidney where hypoxia is the major stimulus for EPO expression under the control of an oxygen-sensing mechanism. A series of previous studies in our laboratories and others have demonstrated the expression of EPO and its receptor (EPOR) in breast cancer cells. In previous work, we found that the administration of antagonists of EPO-EPOR signaling was associated with delayed tumor growth in a rodent syngeneic breast cancer model, suggesting the presence of a functional EPO-EPOR system in cancer. The mechanisms of EPO and EPOR expression in tumor cells requires further study. In vitro experiments using monolayer cultures of breast cancer cells have suggested that EPO and EPOR expression in tumor cells may be hypoxia-regulated. The objective of our current studies was to determine the relationship between the expression of EPO, EPOR and tumor hypoxia in breast cancer to test the hypothesis that EPO or EPOR expression in malignant cells may be associated with the presence of in vivo tumor hypoxia, an important factor involved in resistance to radiation treatment, tumor aggressiveness and poor prognosis. Thirty-eight patients with primary breast cancer were enrolled in a tumor hypoxia study under a research protocol approved by the Institutional Review Board at the University of North Carolina Hospitals. All patients provided signed informed consent. The patients received an intravenous infusion of the hypoxia marker pimonidazole hydrochloride (Hypoxyprobe-1™) prior to tumor biopsy. Two or more biopsies were obtained from 33 tumors and 5 primary tumors had a single biopsy available. Contiguous sections from a total of 93 biopsies were analyzed by immunohistochemistry using monoclonal antibodies for the expression of EPO and EPOR and pimonidazole binding. We found EPO expression in tumor cells in 94% of the biopsies. Focal EPO expression pattern was observed in many tumors. EPOR expression was present in 93% of biopsies. The pattern of EPOR immunoreactivity was predominantly cytoplasmic but was found to be localized to the membrane in some sections. In many tumors, co-localization of EPO and EPOR expression in tumor cells was present when contiguous sections were examined. Tumor hypoxia was detected in 83% of the biopsies at variable levels and did not always co-localize with EPO or EPOR expression in tumor cells. Semi-quantitative analyses for EPO immunostaining and tumor hypoxia on a section-by-section basis revealed a significant positive correlation between levels of micro-regional EPO expression and pimonidazole binding (r = 0.6, P < 0.0001, n=93 by two-tailed Spearman’s rank correlation analysis). A similar significant positive correlation was found between levels of EPOR expression and pimonidazole binding (r = 0.63, P < 0.0001, n=93). In addition, there was a significant association between the semi-quantitative EPO score in tumor cells and the EPOR score (r = 0.6, P < 0.0001, n=93). We also determined the micro-vessel density (MVD), a marker of tumor angiogenesis, in 35 biopsies using factor VIII immunostaining. There was no correlation between EPO or EPOR expression and MVD in these samples. In conclusion, these data demonstrate for the first time that EPO and EPOR expression in breast cancer cells correlates with in vivo tumor hypoxia in clinical specimens of primary breast cancer.

Pleiotrophin Is Highly Produced by Solid Tumors and Transdifferentiates Human Monocytes Into Endothelial Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3050-3050
Author(s):  
Eric Wirtschafter ◽  
Emily Wong ◽  
Mingjie Li ◽  
Eric Sanchez ◽  
Cathy S Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Endothelial Cells ◽  
Blood Vessel ◽  
Cancer Cells ◽  
Solid Tumors ◽  
Tumor Cells ◽  
Breast Cancer Cells ◽  
Human Monocytes ◽  
Rt Pcr

Abstract Abstract 3050 Poster Board II-1026 We have previously shown that tumor cells from multiple myeloma (MM) patients express pleiotrophin (PTN). This protein is elevated in the serum of MM patients and we have shown that, in combination with M-CSF, it induces the transdifferentiation of monocytes into endothelial cells both in vitro and in vivo (Chen et al. Blood 2009). In this study, we determined the level of PTN expression in a variety of solid tumor types including breast, ovarian, prostate, and pancreatic cancers, and examined whether PTN produced by tumor cells from these different types of solid tumors could also induce transdifferentiation of human monocytes into endothelial cells both in vitro and in vivo. Our results showed that breast, ovarian, prostate, and pancreatic cancers all produce high levels of PTN as determined by RT-PCR, Western blot analysis, immunohistochemical staining, and measurement of the level of this growth factor secreted into the medium derived from cultured tumor cells whereas normal peripheral blood mononuclear cells (PBMCs) showed no expression of this protein. Next, monocytes derived from CD14-selected PBMCs or the THP-1 cell line were exposed to breast, ovarian, prostate, and pancreatic cancer cells on collagen I-coated Transwell plates with M-CSF. Following culture of these cells for 5-14 days, both fresh CD14+ cells and THP-1 cells changed their morphology into endothelial-like cells and expressed the endothelial genes and proteins Flk-1 and Tie-2 as determined with RT-PCR and Western blot analysis, respectively. These endothelial cell-inducing effects on monocytes were blocked with anti-PTN antibodies. Next, we determined whether human monocytes could be incorporated into blood vessels and express endothelial cell markers in vivo within solid tumors that express PTN. Human breast cancer cells (MDA-MB-231) alone, THP-1 monocytes transduced with the green fluorescent protein (GFP) gene, or the combination of both cell types were injected subcutaneously into severe combined immunodeficient (SCID) mice. Mice were sacrificed 8 weeks later and the tumor tissue was fixed and cut into frozen sections. Breast cancer cells or GFP+ THP-1 monocytes alone did not demonstrate the presence of GFP-marked cells within tumor blood vessels. When breast cancer cells and GFP+ THP-1 cells were injected together, GFP-marked cells were found within tumor blood vessels; and, moreover, double staining of serial sections of the breast cancer with anti-Tie-2 and CD31 antibodies showed a similar distribution pattern of staining as the blood vessel cells showing the presence of GFP. We also examined endothelial gene expression in these samples using RT-PCR. The results showed that the THP-1 monocytes alone or breast cancer cells alone did not express endothelial genes whereas THP-1 monocytes mixed with breast cancer cells showed endothelial gene (FLK-1, Tie-2) expression. These data show that solid tumors through expression of PTN support new blood vessel formation by the transdifferentiation of monocytes into endothelial cells and provide a new potential target for inhibiting early blood vessel formation within tumors. Disclosures No relevant conflicts of interest to declare.

scholarly journals In Vivo Anti-Tumor Effects of Citral on 4T1 Breast Cancer Cells via Induction of Apoptosis and Downregulation of Aldehyde Dehydrogenase Activity

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3241 ◽  
Author(s):  
Nigjeh ◽  
Yeap ◽  
Nordin ◽  
Rahman ◽  
Rosli
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Aldehyde Dehydrogenase ◽  
Breast Cancer Cells ◽  
Oral Feeding ◽  
Aldh Activity ◽  
Secondary Tumors ◽  
4T1 Breast Cancer

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death among females globally. The tumorigenic activities of cancer cells such as aldehyde dehydrogenase (ALDH) activity and differentiation have contributed to relapse and eventual mortality in breast cancer. Thus, current drug discovery research is focused on targeting breast cancer cells with ALDH activity and their capacity to form secondary tumors. Citral (3,7-dimethyl-2,6-octadienal), from lemon grass (Cymbopogon citrates), has been previously reported to have a cytotoxic effect on breast cancer cells. Hence, this study was conducted to evaluate the in vivo effect of citral in targeting ALDH activity of breast cancer cells. BALB/c mice were challenged with 4T1 breast cancer cells followed by daily oral feeding of 50 mg/kg citral or distilled water for two weeks. The population of ALDH+ tumor cells and their capacity to form secondary tumors in both untreated and citral treated 4T1 challenged mice were assessed by Aldefluor assay and tumor growth upon cell reimplantation in normal mice, respectively. Citral treatment reduced the size and number of cells with ALDH+ activity of the tumors in 4T1-challenged BALB/c mice. Moreover, citral-treated mice were also observed with smaller tumor size and delayed tumorigenicity after reimplantation of the primary tumor cells into normal mice. These findings support the antitumor effect of citral in targeting ALDH+ cells and tumor recurrence in breast cancer cells.

scholarly journals Platelet glycoprotein VI promotes metastasis through interaction with cancer cell-derived Galectin-3

Blood ◽  
2020 ◽  
Author(s):  
Elmina Mammadova-Bach ◽  
Jesus Gil-Pulido ◽  
Edita Sarukhanyan ◽  
Philipp Burkard ◽  
Sergey Shityakov ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Cell ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Breast Cancer Cells ◽  
Platelet Adhesion ◽  
Platelet Glycoprotein ◽  
Glycoprotein Vi ◽  
Galectin 3

Increasing evidence suggests that platelets play a predominant role in colon and breast cancer metastasis but the underlying molecular mechanisms remain elusive. Glycoprotein VI (GPVI) is a platelet-specific receptor for collagen and fibrin that triggers platelet activation through immunoreceptor tyrosine-based activation motif (ITAM)-signaling and thereby regulates diverse functions including platelet adhesion, aggregation and procoagulant activity. GPVI has been proposed as a safe antithrombotic target as its inhibition is protective in models of arterial thrombosis with only minor effects on hemostasis. Here, we demonstrate that genetic deficiency of platelet GPVI in mice decreases experimental and spontaneous metastasis of colon and breast cancer cells. Similar results were obtained with mice lacking the spleen-tyrosine kinase Syk in platelets, an essential component of the ITAM-signaling cascade. In vitro and in vivo analyses show that mouse, as well as human GPVI, supports platelet adhesion to colon and breast cancer cells. Using a CRISPR/Cas9-based gene knock-out approach, we identified Galectin-3 as the major counter-receptor of GPVI on tumor cells. In vivo studies demonstrated that the interplay between platelet GPVI and tumor cell-expressed Galectin-3 utilizes ITAM-signaling components in platelets and favors the extravasation of tumor cells. Finally, we showed that JAQ1 F(ab)2-mediated inhibition of GPVI efficiently impairs platelet-tumor cell interaction and tumor metastasis. Our study reveals a new mechanism by which platelets promote the metastasis of colon and breast cancer cells and suggests that GPVI represents a promising target for antimetastatic therapies.

scholarly journals 931 LncRNA Malat1 regulated Serpinb6b signaling suppresses pyroptosis and governs breast cancer dormancy reactivation and through immune evasion

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A977-A977
Author(s):  
Dhiraj Kumar ◽  
Filippo Giancotti
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Single Cell ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Immune Evasion ◽  
Breast Cancer Cells ◽  
Rna Seq

BackgroundMetastatic relapse is the major causes of mortality in patients with cancer and occur due to metastatic reactivation of dormant tumor cells. Early dissemination of tumor cells undergoing a protected period of dormancy in the target organs potentially explains this prevalent clinical behavior.1–4 Long non-coding RNAs (lncRNAs) are involved in various biological processes and diseases. Malat1 is one of the most abundant and highly conserved nuclear lncRNAs and have shown the associated with metastasis and serving as a predictive marker for various tumor progression.5 However, the correlation of tumor intrinsic lncRNAs in regulation of tumor dormancy and immune evasion is largely unknown.MethodsUsing an in vivo screening platform for the isolation of genetic entities involved in either dormancy or reactivation of breast cancer tumor cells, we have identified Malat1 as a positive mediator of metastatic reactivation.4 To dissect the functional role of Malat1 in metastatic reactivation, we developed a clean Malat1 knockout (KO) model using paired gRNA CRISPR-Cas9 in metastatic murine syngeneic breast cancer. As proof of concept we also used inducible knockdown system under in vivo models. To delineate the immune microenvironment, we used single cell RNA-seq, ChIRP-seq, multicolor flowcytometry, RNA-FISH, and coculture experiments.ResultsOur data revealed that deletion of Malat1 induces dormancy and attenuated the metastatic colonization resulting in long-term survival of syngeneic mice model. In contrast, overexpression of Malat1 leads to metastatic reactivation of dormant breast cancer cells. Interestingly, 4T1-Malat1 KO dormant breast cancer cells exhibit metastatic outgrowth in T cells defective mice. Our single-cell RNA-seq and multicolor flowcytometry evaluation reveal enhanced T cells and reduced neutrophils proportions in mice with Malat1 KO cells. This indicates a critical role of immune microenvironment via Malat1-dependent immune evasion. Additionally, Malat1 KO inhibits cancer stemness properties. Similarly, RNA-seq and ChIRP-seq data suggest that KO of Malat1 hampers immune evasion and downregulates metastasis associated genes including Serpins and Wnts. Additionally, our data strongly suggests that Malat1 KO cells persists as non-proliferative dormant cells in lung due to CD8+ T cell-umpired immune activity. Interestingly, rescue experiments suggest that Malat1 or Serpinb6b protects T cell-induced cell death and induces dormancy re-awakening thereby rescue the metastatic potential of 4T1 Malat1 KO cells. Combination of Malat1 ASO with double immune checkpoint inhibitors greatly affects the metastatic outgrowth in breast cancer.ConclusionsTaken together, our studies demonstrate that tumor intrinsic Malat1 regulates Serpinb6b that eventually controls immune evasion and promote dormancy metastatic reactivation.AcknowledgementsNGS data generated was supported by Core grant CA016672(ATGC) and NIH 1S10OD024977-01 award to the ATGC. Single cell RNA sequencing data was supported by the CPRIT Single Core grant RP180684. The Advanced Cytometry & Sorting Core Facility is supported by NCI P30CA016672.ReferencesArun G, Diermeier S, Akerman M, et al. Differentiation of mammary tumors and reduction in metastasis upon Malat1 lncRNA loss. Genes Dev 2016 January 1;30(1):34–51.Filippo G Giancotti. Mechanisms governing metastatic dormancy and reactivation. Cell 2013 November 7;155(4):750–764.Gao H, Chakraborty G, Lee-Lim AP, et al. The BMP inhibitor Coco reactivates breast cancer cells at lung metastatic sites. Cell 2012b;150:764–779.Gao H, Chakraborty G, Lee-Lim AP, et al. Forward genetic screens in mice uncover mediators and suppressors of metastatic reactivation. Proc Natl Acad Sci U S A 2014 November 18;111(46):16532–16537.Huang D, Chen J, Yang L, et al. NKILA lncRNA promotes tumor immune evasion by sensitizing T cells to activation-induced cell death. Nat Immunol 2018;19:1112–1125.

A novel therapeutic to enhance the immunogenicity of breast cancer cells.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 119-119
Author(s):  
Priya Vishnubhotla ◽  
Amr Khaled ◽  
Anne Showalter ◽  
Jeremiah Oyer ◽  
Robert Igarshi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Nk Cells ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Breast Cancer Cells ◽  
Nk Cell ◽  
Checkpoint Inhibitors ◽  
Cancer Recurrence ◽  
Molecular Signature ◽  
Cellular Immunotherapy

119 Background: Breast cancer is a challenge for immunotherapy because of its inherent genetic heterogeneity and decreased immunogenicity. A possible solution is to generate dying breast cancer cells that operate like a vaccine to stimulate tumor-specific immunity. This is termed immunogenic cell death (ICD) and is characterized by a unique molecular signature, involving the release of molecules that attract and stimulate phagocytes and sensitize tumor cells to killing by natural killer (NK) cells. However, the current doses of drugs used to induce ICD may be too high to translate into clinically relevant regimens. Methods: Our group discovered a novel peptide, CT20p, that is effective at nanomolar concentrations and can be delivered to breast tumors using targeted nanoparticles. CT20p works by inhibiting a unique protein folding complex, called chaperonin-containing TCP-1 (CCT), which is highly expressed in cancer cells but not normal cells. Using triple negative breast cancer (TNBC) and normal cell lines as well as patient-derived tumor cells, we examined the biological consequences of CCT inhibition by CT20p in terms of the induction of endoplasmic reticulum (ER) stress, through the accumulation of unfolded proteins, and the release of the danger signals associate with ICD that could stimulate innate immunity. Results: Dying TNBC cells treated with CT20p displayed alterations in PERK, a mediator of the unfolded protein response (UPR), which resulted in the membrane translocation of calreticulin (Crt), an “eat me”’ signal and a key marker of ICD. CT20p-killed TNBC cells were more readily phagocytosed, and NK cells more effectively killed remaining cancer cells. In our experiments normal breast epithelial cells, macrophages or NK cells were unaffected by CT20p. Conclusions: Our study suggests that inhibition of CCT by CT20p generates dying cancer cells that stimulate innate immune responses, through the release of signals like Crt, to attract phagocytes and promote NK cell cytotoxicity. By enhancing the immunogenicity of breast cancer cells, CT20p could increase responsiveness to to checkpoint inhibitors or cellular immunotherapy, hence providing more complete protection from breast cancer recurrence and metastasis.

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