Aggressive Type Of Breast Cancer Research Articles

A novel combinatorial approach usingsulforaphane- and withaferin A-rich extracts for prevention of estrogen receptor-negative breast cancer through epigenetic and gut microbial mechanisms.

Estrogen receptor-negative [ER(-)] mammary cancer is the most aggressive type of breast cancer (BC) with higher rate of metastasis and recurrence. In recent years, dietary prevention of BC with epigenetically active phytochemicals has received increased attention due to its feasibility, effectiveness, and ease of implementation. In this regard, combinatorial phytochemical intervention enables more efficacious BC inhibition by simultaneously targeting multiple tumorigenic pathways. We, therefore, focused on investigation of the effect of sulforaphane (SFN)-rich broccoli sprouts (BSp) and withaferin A (WA)-rich Ashwagandha (Ash) combination on BC prevention in estrogen receptor-negative [ER(-)] mammary cancer using transgenic mice. Our results indicated that combinatorial BSp + Ash treatment significantly reduced tumor incidence and tumor growth (~ 75%) as well as delayed (~ 21%) tumor latency when compared to the control treatment and combinatorial BSp + Ash treatment was statistically more effective in suppressing BC compared to single BSp or Ash intervention. At the molecular level, the BSp and Ash combination upregulated tumor suppressors (p53, p57) along with apoptosis associated proteins (BAX, PUMA) and BAX:BCL-2 ratio. Furthermore, our result indicated an expressional decline of epigenetic machinery HDAC1 and DNMT3A in mammary tumor tissue because of combinatorial treatment. Interestingly, we have reported multiple synergistic interactions between BSp and Ash that have impacted both tumor phenotype and molecular expression due to combinatorial BSp and Ash treatment. Our RNA-seq analysis results also demonstrated a transcriptome-wide expressional reshuffling of genes associated with multiple cell-signaling pathways, transcription factor activity and epigenetic regulations due to combined BSp and Ash administration. In addition, we discovered an alteration of gut microbial composition change because of combinatorial treatment. Overall, combinatorial BSp and Ash supplementation can prevent ER(-) BC through enhanced tumor suppression, apoptosis induction and transcriptome-wide reshuffling of gene expression possibly influencing multiple cell signaling pathways, epigenetic regulation and reshaping gut microbiota.

Racial and survival disparities in inflammatory breast cancer (IBC) and non-IBC: a population-based study focused on Native Hawaiians and other Pacific Islanders

BackgroundIt is well known that race is an independent predictor of breast cancer mortality and advanced stage at diagnosis. Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer and has distinct clinical and biological features. Previous studies have shown that Blacks have a higher incidence of IBC than Whites. However, the proportion of IBC and the role of race on prognosis in Native Hawaiian and other Pacific Islander (NH/PI) populations with breast cancer are poorly understood. In this study, we aimed to examine the proportion of IBC to non-IBC in NH/PIs and to identify the clinicopathological, biological, and socioeconomic factors associated with the overall survival of NH/PIs compared to other races.MethodsUtilizing a comprehensive cancer registry from the largest hospital in Hawaii, newly diagnosed primary invasive breast cancer patients diagnosed between 2000 and 2018 were identified. Univariate and multivariate Cox proportional hazards models were used to test the association between race and clinical outcomes. Variables with P-values <0.05 in the univariate analysis and race (variable of interest) were included in a multivariate analysis.ResultsThe cohort included 3691 patients, 60 of whom had IBC. NH/PI race had the highest proportion of IBC compared to other races (3.44%) but was not found to be an independent poor prognostic factor in IBC (HR 1.17 [95%CI 0.26-5.22]). Conversely, NH/PI race was associated with worse survival outcomes in patients with non-IBC (HR 1.65 [95%CI, 1.14-2.39]) along with other factors such as lack of insurance, underinsured status, triple-negative breast cancer (TNBC) subtype, age, and advanced clinical stage.ConclusionsThe findings of this study highlight that NH/PIs had higher rates of IBC and inferior survival in non-IBC compared to other races but not in IBC. It is essential to disaggregate NH/PI race from Asians in future population-based research studies. Further research is needed to understand the factors contributing to higher rates of IBC and poor survival outcomes in NH/PIs with non-IBC as well as targeted interventions to improve breast cancer outcomes in this population to ultimately help improve survival rates and reduce health inequities in NH/PIs with breast cancer.

Towards a More Efficient Breast Cancer Therapy Using Active Human Cell Membrane-Coated Metal–Organic Frameworks

The recent description of well-defined molecular subtypes of breast cancer has led to the clinical development of a number of successful molecular targets. Particularly, triple-negative breast cancer (TNBC) is an aggressive type of breast cancer with historically poor outcomes, mainly due to the lack of effective targeted therapies. Recent progresses in materials science have demonstrated the impressive properties of metal–organic framework nanoparticles (NPs) as antitumoral drug delivery systems. Here, in a way to achieve efficient bio-interfaces with cancer cells and improve their internalization, benchmarked MIL-100(Fe) NPs were coated with cell membranes (CMs) derived from the human TNBC cell line MDA-MB-468. The prepared CMs-coated metal–organic framework (CMs_MIL-100(Fe)) showed enhanced colloidal stability, cellular uptake, and cytotoxicity in MDA-MB-468 cells compared to non-coated NPs, paving the way for these human CMs-coated MIL-100(Fe) NPs as effective targeted therapies against the challenging TNBC.

Chlorin Conjugates in Photodynamic Chemotherapy for Triple-Negative Breast Cancer.

Breast cancer (BC) is the most common type of cancer in women and the number of new cases in the US is still increasing each year. Triple-negative breast cancer (TNBC), which comprises 15-20% of all breast cancer, is a heterogeneous disease and is considered the most aggressive type of breast cancer due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expressions for treatments. Traditional chemotherapy is the standard protocol for the treatment of TNBC. Toxicity and multidrug resistance are major drawbacks to chemotherapy. The lack of molecular targets and poor prognosis for TNBC prompts an urgent need to discover novel therapeutic strategies to improve clinical outcomes and quality of life for patients. Photodynamic therapy (PDT) or light treatment is a binary anti-cancer procedure that uses a photosensitizer (PS) that, upon light activation, produces cytotoxic oxygen species, destroying tumor cells. PDT is minimally invasive and can be repeated a few times without accumulating significant toxicity in the surrounding tissues. The primary goal of this study was to investigate in vitro photodynamic chemotherapy as a ternary combination therapy using our synthesized photosensitizers (chlorin-vitamin conjugates and their corresponding indium complexes) co-treated with known chemotherapeutic agents (taxol, doxorubicin, cisplatin, fluorouracil, or methotrexate) in the presence of light and determine the optimum conditions as a pre-clinical study of an enhanced tumoricidal effect against TNBC. Our results indicated that the best combination for an effective chemophotodynamic effect involves a ternary treatment of the indium complex of the chlorin-lipoic acid conjugate (InCLA) co-treated with taxol, which exhibited strong synergism at the nanomolar concentration when combined in the presence of visible light irradiation. Other ternary combinations containing taxol with a synergistic anti-tumor effect against TNBC include chlorin-pantothenic acid (CPA) and chlorin-biotin (CBTN) conjugates. Several other ternary combinations containing InCLA, CBTN, and CPA with either cisplatin, fluorouracil, or methotrexate were identified to generate a synergistic or additive effect. The light dosage remained constant, but the dosages of photosensitizers and chemotherapy drugs were varied to obtain the lowest possible concentration for the desired effect. The synergistic, additive or antagonistic effects of the drug combinations were determined based on the Chou-Talalay method, with InCLA-taxol having the lowest combination index (CI) of 0.25. Fluorescence and transmission electron microscopy (TEM) images provided evidence of apoptosis as the preferred mode of cell death. Our study demonstrated the combination of PDT and chemotherapy as a potential treatment option for TNBC patients.

Mitochondria-targeted ruthenium complexes can be generated in vitro and in living cells to target triple-negative breast cancer cells by autophagy inhibition

Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer, which owned severe resistance to platinum-based anticancer agents. Herein, we report a new metal-arene complex, Ru-TPE-PPh3, which can be synthesized in vitro and in living cells with copper catalyzed the cycloaddition reaction of Ru-azide and alkynyl (CuAAC). The complex Ru-TPE-PPh3 exhibited superior inhibition of the proliferation of TNBC MDA-MB-231 cells with an IC50 value of 4.0 μM. Ru-TPE-PPh3 could induce the over production of reactive oxygen species (ROS) to initiate the oxidative stress, and further damage the mitochondria both functionally and morphologically, as loss of mitochondrial membrane potential (MMP) and cutting the supply of adenosine triphosphate (ATP), the disappearance of cristae structure. Moreover, the damaged mitochondria evoked the occurrence of mitophagy with the autophagic flux blockage and cell death. The complex Ru-TPE-PPh3 also demonstrated excellent anti-proliferative activity in 3D MDA-MB-231 multicellular tumor spheroids (MCTSs), indicating the potential to inhibit solid tumors in living cells. This study not only provided a potent agent for the TNBC treatment, but also demonstrated the universality of the bioorthogonally catalyzed lethality (BCL) strategy through CuAAC reation.

Combination Nano-Delivery Systems Remodel the Immunosuppressive Tumor Microenvironment for Metastatic Triple-Negative Breast Cancer Therapy.

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer for which effective therapies are lacking. Targeted remodeling of the immunosuppressive tumor microenvironment (TME) and activation of the body's immune system to fight tumors with well-designed nanoparticles have emerged as pivotal breakthroughs in tumor treatment. To simultaneously remodel the immunosuppressive TME and trigger immune responses, we designed two potential therapeutic nanodelivery systems to inhibit TNBC. First, the bromodomain-containing protein 4 (BRD4) inhibitor JQ1 and the cyclooxygenase-2 (COX-2) inhibitor celecoxib (CXB) were coloaded into chondroitin sulfate (CS) to obtain CS@JQ1/CXB nanoparticles (NPs). Then, the biomimetic nanosystem MM@P3 was prepared by coating branched polymer poly(β-amino ester) self-assembled NPs with melittin embedded macrophage membranes (MM). Both in vitro and in vivo, the CS@JQ1/CXB and MM@P3 NPs showed excellent immune activation efficiencies. Combination treatment exhibited synergistic cytotoxicity, antimigration ability, and apoptosis-inducing and immune activation effects on TNBC cells and effectively suppressed tumor growth and metastasis in TNBC tumor-bearing mice by activating the tumor immune response and inhibiting angiogenesis. In summary, this study offers a novel combinatorial immunotherapeutic strategy for the clinical TNBC treatment.

Abstract 5697: MILIP drives triple-negative breast cancer through complexing with transfer RNAs to promote protein production

Abstract Despite the progress in endocrine therapy, targeted therapy and immunotherapy, the treatment of triple-negative breast cancer (TNBC), one of the most aggressive types of breast cancer, is challenging. This is closely associated with the lack of effective molecular targets in TNBC cells for therapeutic intervention. Here we report that the long noncoding RNA (lncRNA) MILIP drives TNBC cell survival, proliferation and tumorigenicity through complexing with transfer RNAs (tRNAs) to promote protein production, and thus represents a potential therapeutic target in TNBC. MILIP was expressed at high levels in TNBC cells that commonly harbor loss-of-function mutations of the tumor suppressor p53, yet MILIP silencing diminished TNBC cell viability and retarded TNBC xenograft growth, indicating that MILIP functions distinctively in TNBC beyond its well-established role in repressing p53 in other types of cancers. Mechanistical investigations revealed that MILIP interacted with eukaryotic translation elongation factor 1 alpha 1 (eEF1α1) and formed an RNA-RNA duplex with tRNALeu and tRNASer, type II tRNAs, through their variable loops, thus facilitating the binding of eEF1α1 to these tRNAs. Disrupting the interaction between MILIP and eEF1α1 or tRNAs diminished protein production and cell viability, with therapeutic potential revealed where targeting MILIP using Gapmers inhibited TNBC growth and cooperated with the clinically available protein synthesis inhibitor omacetaxine mepesuccinate in vivo. Collectively, these results identified MILIP as an RNA translation elongation factor to promote protein production in TNBC cells and demonstrated that experimental therapy with MILIP Gapmers inhibits TNBC growth, indicating MILIP targeting is a potential avenue for developing improved TNBC treatment through blocking protein synthesis. Citation Format: Yuchen Feng, Simin Zheng, Xiaohong Zhao, Yuanyuan Zhang, Ran Xu, Liang Xu, Thomas Preiss, Lei Jin, Jinnan Gao, Xu Dong Zhang. MILIP drives triple-negative breast cancer through complexing with transfer RNAs to promote protein production [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5697.

Abstract 5935: Non-allosteric inhibition of enolase 1 sensitizes triple-negative breast cancer for checkpoint inhibitors

Abstract Background: Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer that commonly returns and spreads. Currently, very few options are available for TNBC treatment. Cancer cells exploit glycolytic machinery for the Warburg effect and aerobic glycolysis. Enolase 1 (ENO1) is the glycolytic enzyme expressed in most tissues, and many cancer cells have higher expression. Apart from the glycolytic role in the cytosol, ENO1 also plays different roles in cancer cells, including as a surface receptor. Method: non-allosteric chemical inhibition was developed and tested in vitro for its efficacy and target validation. Subsequently, in vivo examinations were conducted on emerging small molecules in syngeneic and patient-derived murine models of breast cancer to unveil their anti-tumor efficacy. Results: Our non-allosteric small molecule inhibitor, SU212, binds to ENO1 and restricts its movement within cells. SU212 treatment leads to the accumulation of ENO1 in the nucleus where it restrains the activity of c-Myc. The treatment causes the production of truncated ENO1 called myc promoter-binding protein 1 (MBP-1), which limits the activity of c-Myc. Stand-alone treatment of SU212 restrains the tumor progression and metastasis in orthotopic syngeneic and PDX mouse models. Combining SU212 and Anti-PD1 significantly inhibits tumor growth and metastasis in mouse models. C-Myc is linked to protein transcription that aids immune resistance and tumor evasion of immune surveillance. Suppression of c-Myc activity via SU212 treatment sensitizes the TNBC tumors for anti-PD1 therapy. Conclusions: This study provides compelling preclinical data for further development of SU0212 as an immune therapy sensitizer for the treatment of TNBC. Citation Format: Dhanir Tailor, Fernando Jose Garcia-Marques, Abel Bermudez, Wenqi Li, Arpit Dheeraj, Sharon J. Pitteri, Sanjay V. Malhotra. Non-allosteric inhibition of enolase 1 sensitizes triple-negative breast cancer for checkpoint inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5935.

Abstract 6933: Decoding the archetypes and eco-hubs of triple-negative breast cancer in responses to chemotherapy

Abstract Triple-negative breast cancer (TNBC) is a highly aggressive type of breast cancer commonly treated with neoadjuvant chemotherapy (NAC). While about 50% of patients achieve a pathological complete response (pCR), the remainder often develop resistance and metastasis, leading poor survivals. Currently, the factors linking pre-treatment cancer cells and the tumor microenvironment (TME) to NAC response are unclear. To investigate this question, we conducted single-cell RNA sequencing on fresh pre-treatment core biopsy samples collected from patients in the ARTEMIS clinical trial. We identified 13 gene expression meta-programs of cancer cells and about 50 cell states of immune and stromal cell types. Based on the cancer cells alone, we identified four TNBC archetypes at patient-level: luminal secretory-associated (LSA), basal-associated (BA), immunoreactive (IR), and luminal androgen receptor (LAR). Notably, the archetype BA and IR were associated with non-pCR and pCR, respectively. Additionally, we found the TNBC ecosystem was composed of eight eco-hubs, reflecting the co-occurrence patterns of cancer and TME cell states. These eco-hubs revealed different cell community across archetypes and NAC outcomes. For example, an eco-hub with a co-occurrence of interferon response-related cancer cells and immune cells was prevalent in the archetype IR and pCR patients. To facilitate a clinical application, we further developed a 13-gene-based machine learning model to predict NAC response. In summary, these results provide new insights into the cellular determinants of TNBC biology and chemotherapeutic response. Citation Format: Yun Yan, Yiyun Lin, Tapsi Kumar, Shanshan Bai, Jianzhuo Li, Tuan Tran, Min Hu, Elizabeth Ravenberg, Maia Rauch, Alyson Clayborn, Alastair Thompson, Bora Lim, Lei Huo, Stacy Moulder, Clinton Yam, Nicholas Navin. Decoding the archetypes and eco-hubs of triple-negative breast cancer in responses to chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6933.

Abstract 6951: The role of estrogen-dependent activation of p38 MAPK signaling pathway in inflammatory breast cancer

Abstract Inflammatory breast cancer (IBC) is a rare and aggressive type of breast cancer in which the lymphatic vessels become blocked by cancer cells in the breast tissue. The five-year survival rate for this type of cancer is around 40%, one of the worst among breast cancer. Most IBCs are estrogen receptor (ER) and progesterone receptor (PR) negative and HER2 positive, with some presenting an amplification of HER2 while others are ER, PR, and HER2 negative, formally known as the triple-negative (TNBC) subtype. However, it has been reported that treatment with 17β-Estradiol (E2) of ER-negative IBC and non-IBC cells can exert rapid non-genomic signaling mediated by ERα-36, GPR30, and/or estrogen receptor beta, activating MAPK pathways involved in oncogenic phenotypes. Previous data generated in our lab showed that when cells were treated with estradiol it led to increased phosphorylation levels of p38. However, the specific role p38 MAPK signaling takes on in IBC is unknown. Thus, this study centers on examining the role of estradiol and p38 regulation in the triple-negative IBC cell line model, SUM149PT. We hypothesize that upon estradiol treatment p38 signaling pathway is activated resulting in the over-expression of pro-inflammatory cytokines which regulate pro-tumorigenic phenotypes including the growth and survival of IBC cells. Inflammatory cytokines can promote pro-oncogenic features by promoting cell proliferation, angiogenesis, and immune suppression. We treated SUM149 IBC cells with 10nM of estradiol and measured the levels of human cytokines using a Human Cytokine Antibody Array. In addition, treatment using SB202190, a potent p38 inhibitor, caused a significant decrease in cell viability of several breast cancer cell lines in a dose-dependent manner. Ongoing studies include assessing the effects of p38 inhibition proliferation, invasion, and migration. In summary, a better characterization of the effect of E2 and p38 activation in ER-negative cell lines may provide great insight into novel targeted therapies for IBC. Citation Format: Keyla V. Ramirez, Adrian D. Bonilla-González, Jeisac Guzman-Rivera, Esther A. Peterson-Peguero. The role of estrogen-dependent activation of p38 MAPK signaling pathway in inflammatory breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6951.

Abstract 7151: Targeting metabolic pathway in triple negative breast cancer with a small molecule inhibitor

Abstract Background: Triple Negative Breast Cancer (TNBC) is the most aggressive type of breast cancer, making up 15-20% of diagnosed cases, and has high rates of metastasis and recurrence. Most women with this disease experience a recurrence after curative-intent therapy for early breast cancer, while a smaller proportions are diagnosed with distant metastases initially. Cancer cells are characterized by their reprogramming of glucose metabolism. Cancer cells show increased proliferation along with higher energy and substrate demands. Through our efforts to find effective therapies for TNBC, we have identified CET019, a new small molecule that effectively suppresses the growth of breast cancer cells. Methods: Cell viability and clonogenic assays were performed on a range of TNBC cells, including MDA-MB-231, MDA-MB-468, SUM159, HCC1395, HCC1806, EMT6, and 4T1. Cell cycle distribution was assessed through flow cytometry. LC-MS/MS analysis was performed on TMT-labeled samples for global proteome profiling. The efficacy of CET019 (30 mg/kg) was tested using tumor and patient derived xenograft studies. Results: Our studies show that CET019 suppresses the clonogenic potential and growth of various triple-negative breast cancer cells. The CET019 treatment causes cell cycle arrest in TNBC cells at the G2/M phase. Proteomics analysis suggests that CET019 specifically affects metabolic and proteosomal pathways. In vivo studies with CET019 found an inhibition of tumor growth kinetics in the mouse xenograft study with different TNBC models, as compared to the control group. We also observed that CET019 inhibited metastatic lung nodules. The results were further substantiated in three Patient Derived Xenograft (PDX) models. Conclusion: In summary, our study has identified a novel small molecule candidate CET019 as a promising lead candidate for TNBC treatment, paving the way for further development.“The complete chemical structures of the compounds used will be disclosed at the time of presentation at the meeting.” Citation Format: Arpit Dheeraj, Fernando Jose Marques, Dhanir Tailor, Abel Bermudez, Benedikt Grau, Sharon Pitteri, Sanjay V. Malhotra. Targeting metabolic pathway in triple negative breast cancer with a small molecule inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7151.

Abstract 5288: Soy isoflavone genistein reboosts targeted therapy sensitivity in triple negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is a very aggressive type of breast cancer that does not expression important proteins called estrogen, progesterone and HER2. This makes TNBC hard to treat because it does not respond to common targeted treatments. However, recent treatments using the immune system to target key immune proteins such as PD-1 and PD-L1 have been successful in many types of cancer. This form of immunotherapy works by blocking PD-1/PD-L1 pathway and leads to stimulating the body's own immune system to recognize and attack cancer cells, thus providing a potential new treatment option for TNBC patients. Nevertheless, only approximately 30% of TNBC patients may respond to these drugs, suggesting the majority of TNBC patients would not benefit from these innovative immunotherapies. It is believed that low levels of immune cells and PD-L1 expression in tumors are the primary reasons for the lack of response or resistance to anti-PD-1/PD-L1 treatments. The use of nontoxic and healthy food and nutrition to increase treatment response is an emerging field of cancer research. Our studies showed that adding genistein (GE), a bioactive dietary component found in soybean products such as soy milk, soy protein and tofu, could significantly enhance the efficacy of anti-PD-1 immunotherapy in a TNBC mouse model that was previously not responsive to the treatment. Our research also found that soybean GE can increase tumor immune response by significantly recruiting active immune cells into the tumor and increasing PD-L1 expression. Our studies will help to establish a novel nutrition-based intervention targeting TNBC patients who might not qualify for this treatment initially. Eventually, we will develop a novel strategy of administering a tailored dietary plan to resensitize these patients to emerging anti-PD-1/PD-L1 immunotherapies. Citation Format: Taiwo Bankole, Zhenhai Li, Yuanyuan Li. Soy isoflavone genistein reboosts targeted therapy sensitivity in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5288.

Abstract 4529: Characterization of PARP inhibitor combination therapies in triple-negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer, with limited targeted treatment options. TNBC patients can, however, benefit from targeted drugs known as Poly (ADP-Ribose) Polymerase inhibitors (PARPi). PARPi disrupt DNA repair pathways by targeting tumors with germline BRCA1/2 mutations (BRCA-MUT) via synthetic lethality and PARP-DNA trapping mechanisms. Only 15-20% of the TNBC patient population are BRCA-MUT and can thus benefit from PARPi. However, preclinical studies and clinical trials have suggested that PARPi can also be effective in BRCA1/2 wild-type (BRCA-WT) cancer cells that have genomic phenotypes similar to BRCA-MUT cells, a phenomenon known as BRCAness. Previously, we used whole transcriptome analysis in a panel of TNBC cell lines to identify a 63-gene signature for BRCAness. The 63-gene signature was shown to predict response to PARPi with an accuracy of 86% in patient-derived xenografts, and was present in 45% of TNBC patients. We hypothesize that targeting genes in this 63-gene signature can enhance the sensitivity of PARPi in BRCA-WT and BRCA-MUT TNBC cells. Our aim is to identify and target genes from this signature that are involved in DNA synthesis and repair pathways, to identify effective combination strategies with PARPi. Methods: Using a PARPi-resistant TNBC cell line, MDAMB231, we carried out an siRNA screen of six genes from the 63-gene signature (BARD1, BUB1, RRM2, FEN1, EXO1, and USP1), chosen based on DNA repair functions and small-molecule inhibitor availability. The gene knockdowns were combined with the application of a potent PARPi, talazoparib, to determine the impact on DNA damage and cell death in TNBC cell lines. We then focused on targeting FEN1 function with the inhibitor LNT1. Using the Chou & Talalay combination index, we combined LNT1 with talazoparib to determine drug synergy in TNBC cell lines. Results: The individual siRNA knockdowns of BARD1, BUB1, FEN1, EXO1, and USP1, in combination with talazoparib, led to increased γ-H2AX and cleaved-caspase 3 levels, indicating augmentation of DNA damage and apoptosis. In particular, the FEN1 inhibitor, LNT1 demonstrated efficacy as a single-agent and synergy in combination with talazoparib in both BRCA-WT and BRCA-MUT TNBC cell lines. Conclusions: The siRNA screens, in combination with talazoparib, show that there are indeed targets within the 63-gene signature that can be used with PARPi that enhance DNA damage and cell death. The drug synergy shown between LNT1 and talazoparib in both BRCA-WT and BRCA-MUT TNBC cells suggests that LNT1 with PARPi could be an effective targeted combination approach, with great potential for TNBC patients. Citation Format: Elicia Fyle, Djihane Abdesselam, Mallory Frederick, Saima N. Hassan. Characterization of PARP inhibitor combination therapies in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4529.

Epithelial to mesenchymal transition (EMT) in metaplastic breast cancer and phyllodes breast tumors.

Epithelial-mesenchymal transition (EMT), a transdifferentiation program whereby epithelial cells acquire mesenchymal phenotype, is essential during embryonic development. EMT has also been implicated in cancer progression by conferring migratory and metastatic potential, as well as cell plasticity and stem cell like traits, to cancer cells. Metaplastic breast carcinoma (MBC) is a rare aggressive type of breast cancer characterized by the presence of heterologous elements, typically by the existence of epithelial and mesenchymal components. Phyllodes tumors (PTs) are uncommon fibroepithelial neoplasms consisting of epithelial and mesenchymal elements. Although various hypotheses have been proposed on the pathogenesis of these biphasic tumors, there is growing evidence supporting the theory that PTs and MBC could both correlate with cancer related EMT. This review summarizes the existing literature on the emerging role of EMT in the pathogenesis of MBC and PTs. Both malignant PTs and MBC are characterized by poor prognosis. Therefore, several anti-EMT targeting strategies such as blocking upstream signaling pathways, targeting the molecular drivers of EMT and targeting mesenchymal cells and the extracellular matrix, could potentially represent a promising therapeutic approach for patients suffering from these aggressive neoplasms.

Estrogen receptor beta suppresses the androgen receptor oncogenic effects in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer associated with poor prognosis and limited treatment options. The androgen receptor (AR) has emerged as a potential therapeutic target for luminal androgen receptor (LAR) TNBC. However, multiple studies have claimed that anti-androgen therapy for AR-positive TNBC only has limited clinical benefits. This study aimed to investigate the role of AR in TNBC and its detailed mechanism. Immunohistochemistry and TNBC tissue sections were applied to investigate AR and nectin cell adhesion molecule 4 (NECTIN4) expression in TNBC tissues. Then, in vitro and in vivo assays were used to explore the function of AR and estrogen receptor beta (ERβ) in TNBC. Chromatin immunoprecipitation sequencing (ChIP-seq), co-immunoprecipitation (co-IP), molecular docking method, and luciferase reporter assay were performed to identify key molecules that affect the function of AR. Based on the TNBC tissue array analysis, we revealed that ERβ and AR were positive in 21.92% (32/146) and 24.66% (36/146) of 146 TNBC samples, respectively, and about 13.70% (20/146) of TNBC patients were ERβ positive and AR positive. We further demonstrated the pro-tumoral effects of AR on TNBC cells, however, the oncogenic biology was significantly suppressed when ERβ transfection in LAR TNBC cell lines but not in AR-negative TNBC. Mechanistically, we identified that NECTIN4 promoter -42bp to -28bp was an AR response element, and that ERβ interacted with AR thus impeding the AR-mediated NECTIN4 transcription which promoted epithelial-mesenchymal transition in tumor progression. This study suggests that ERβ functions as a suppressor mediating the effect of AR in TNBC prognosis and cell proliferation. Therefore, our current research facilitates a better understanding of the role and mechanisms of AR in TNBC carcinogenesis.

Downregulation of TAB182 promotes cancer stem-like cell properties and therapeutic resistance in triple-negative breast cancer cells

TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.

Anti-migratory Properties of Cryoprotective Isoliquiritigenin-zein Phosphatidylcholine Nanoparticles Prevent Triple-negative Breast Cancer through PI3K-mTOR and MMP2/9 Pathways.

Triple-negative breast cancer (TNBC), an aggressive type of breast cancer, remains difficult to treat. Isoliquiritigenin (ISL) is a bioactive compound that is insoluble in water and exhibits significant anti-TNBC activity. We previously prepared oral aqueous ISL@ZLH NPs; however, they were less stable in a freezing environment. Hence, the present study aimed to improve the stability of ISL@ZLH NPs using cryoprotectants that can withstand long storage times and are effective in TNBC treatment by creating an efficient oral drug delivery system. Freeze-dried ISL@ZLH NP powder was prepared by solvent evaporation, followed by the addition of trehalose and sucrose. The freeze-dried ISL@ZLH NP pow was optimized and characterized. The anti-TNBC efficacy and pharmacokinetics of the ISL@ZLH NP-pow were examined in plasma and organs, compared with those of aqueous ISL@ZLH NPs. The ideal particle size of the ISL@ZLH NP pow was 118 nm, which was not filtered out by the glomerulus and allowed the drug to be delivered to the lesions more effectively. Cellular uptake and biodistribution of the ISL@ZLH NP-pow in vivo and in vitro showed prolonged storage in the organs. In addition, cryopreserved ISL@ZLH NP-treated tumors showed significant anti-proliferative and anti-migratory effects through the downregulation of the PI3K-Akt-mToR and MMP2/9 signaling pathways. These results suggest that oral ingestion of cryopreserved ISL@ZLH NP has the potential for longterm storage and can be employed as a clinical therapeutic approach to treat TNBC.

TRIM21 mediates the synergistic effect of Olaparib and Sorafenib by degrading BRCA1 through ubiquitination in TNBC

Triple-negative breast cancer (TNBC) is a heterogeneous and aggressive type of breast cancer with a poor prognosis and a high recurrence rate. Chemotherapy is still the mainstay of treatment for cancer patients without a genetic BRCA mutation, despite the approval of Olaparib, an inhibitor of the poly (ADP-ribose) polymerase (PARP) enzyme. Tripartite motif containing-21 (TRIM21) is one of the TRIM family members that has been investigated in various types of cancer. Here, we found that a low TRIM21 expression level was correlated with poor overall survival of TNBC patients. Knockout of TRIM21 promoted the proliferation of TNBC cells in vivo and in vitro, as well as migratory and invasive capabilities in vitro. Importantly, breast cancer susceptibility gene 1 (BRCA1) was identified as a ubiquitination substrate of TRIM21. It was confirmed that BRCA1 was upregulated after Olaparib treatment, which may explain the relative resistance of BRCA1-proficient TNBC cells to Olaparib. Moreover, Sorafenib, a standard treatment for hepatocellular carcinoma, increased the sensitivity of TNBC cells to Olaparib by promoting TRIM21-mediated ubiquitination degradation of BRCA1. Thus, a synergic effect of Olaparib and Sorafenib was found in vitro and in vivo. This combined treatment also aggravated DNA damage, cell cycle arrest, and apoptosis of TNBC cells. In summary, the findings verified the synergistic effect of Olaparib and Sorafenib and revealed TRIM21 as a potential target for TNBC therapy.

Spindle Cell Carcinoma of the Breast in a Patient with Previous History of Rectal Cancer: A Case Report

Abstract Background Spindle cell carcinoma of the breast is a very rare subtype of metaplastic breast cancer with aggressive behaviour in comparison with invasive ductal carcinoma, which is the most common histological type of breast cancer. It has a poor prognosis and a controversial response to systemic therapy. Aim of this study The aim of this study is to shed light on this uncommon but aggressive type of breast cancer. Case Presentation In this case report, we present a 56-year-old woman with spindle cell carcinoma of the breast with a previous history of treated rectal cancer. She presented with a left breast mass. Ultrasound-guided fine needle aspiration gave results positive for malignancy. A left mastectomy with axillary clearance was done, and the histopathology was spindle cell carcinoma of the breast. The patient refused chemotherapy until five months post-operation when she presented with local recurrence of two small masses at the site of mastectomy. New imaging revealed bilateral pulmonary metastasis. She started on single agent Adriamycin and received a total of six cycles. A CT scan of the chest and abdomen with contrast revealed disease progression. Imaging of the brain showed brain metastasis. The patient refused any kind of further chemotherapy or radiotherapy treatment until she passed away one month later from aspiration pneumonia and its complications. Conclusion Metaplastic breast cancer is an aggressive subtype of breast cancer with rapid progression, a high tendency for distant metastases, a poor response to treatment, and a short survival time.

Radiological characteristics of invasive micropapillary carcinoma of the breast

To analyse the various imaging features of invasive micropapillary carcinoma (IMPC), a distinct variant of breast cancer, by mammography, ultrasound, and contrast-enhanced mammography. This study included 68 female patients with histopathologically proven invasive micropapillary carcinoma who underwent mammography, ultrasound, and contrast-enhanced mammography examinations. The findings encountered by each imaging tool were analysed using the Breast Imaging Reporting and Data System (BI-RADS) lexicon. In this retrospective study, 64.7% of cases were of the pure form of IMPC. Most of the cases showed an aggressive clinical course, with lymphovascular invasion noted in 76.5% of cases, while 60.3% of cases showed associated pathological lymphadenopathy. The N3 stage was reported in 25% of cases. On analysing the mammographic and ultrasound imaging findings, a significant association between irregular shape and a non-circumscribed margin with IMPC was found. Associated calcification was noted in 47% of cases. Pathological enhancement of moderate or marked conspicuity was noted in cases that underwent contrast-enhanced mammography, with the most commonly encountered finding being enhancing irregular and non-circumscribed masses. The mammographic and ultrasound imaging features of IMPC are indistinguishable from other aggressive types of breast cancer. At contrast-enhanced mammography examination, pathological enhancement of moderate to marked conspicuity was shown in all cases. The observed strong association of IMPC with lymphovascular invasion and lymph node metastasis with higher nodal stage in this study mandate meticulous sonographic examination of the axilla, as well as the infra, and supraclavicular regions if pathological axillary lymphadenopathy was noted.