Strategy For Triple-negative Breast Cancer Research Articles

Chemotherapy-induced high expression of IL23A enhances efficacy of anti-PD-1 therapy in TNBC by co-activating the PI3K-AKT signaling pathway of CTLs

Treatment of advanced triple-negative breast cancer (TNBC) is a great challenge in clinical practice. The immune checkpoints are a category of immunosuppressive molecules that cancer could hijack and impede anti-tumor immunity. Targeting immune checkpoints, such as anti-programmed cell death 1 (PD-1) therapy, is a promising therapeutic strategy in TNBC. The efficacy and safety of PD-1 monoclonal antibody (mAb) with chemotherapy have been validated in TNBC patients. However, the precise mechanisms underlying the synergistic effect of chemotherapy and anti-PD-1 therapy have not been elucidated, causing the TNBC patients that might benefit from this combination regimen not to be well selected. In the present work, we found that IL-23, an immunological cytokine, is significantly upregulated after chemotherapy in TNBC cells and plays a vital role in enhancing the anti-tumor immune response of cytotoxic T cells (CTLs), especially in combination with PD-1 mAb. In addition, the combination of IL-23 and PD-1 mAb could synergistically inhibit the expression of Phosphoinositide-3-Kinase Regulatory Subunit 1 (PIK3R1), which is a regulatory subunit of PI3K and inhibit p110 activity, and promote phosphorylation of AKT in TNBC-specific CTLs. Our findings might provide a molecular marker that could be used to predict the effects of combination chemotherapy therapy and PD-1 mAb in TNBC.

Abstract PS03-02: Single-cell metabolic profiling uncovers new precision immunotherapy strategy in triple-negative breast cancer

Abstract Background: Immunotherapy has emerged as a novel cornerstone in the treatment of triple-negative breast cancer (TNBC), while its benefits have been observed in only a limited subset of patients. The intricate metabolic interplay between cancer cells and microenvironmental cells remodels the tumor microenvironment and exerts a significant influence on the responses to immunotherapy. However, there is still a lack of clarity regarding the strategies to target this metabolic crosstalk in order to predict efficacy and enhance sensitivity for immunotherapy. Methods: We conducted single-cell RNA sequencing (scRNA-seq) analysis on a cohort of 27 patients with TNBC receiving either immunotherapy combination regimen or chemotherapy alone. Building upon this foundation, we embarked on a comprehensive investigation of the single-cell metabolic landscape from three distinct perspectives: metabolic genes, metabolic pathways, and metabolic flux, represented by the flux balance analysis (FBA) algorithm Compass. Furthermore, we identified crucial cell subgroups that exhibited a strong correlation with immunotherapy efficacy and elucidated their metabolic characteristics to postulate potential metabolic crosstalk. Then, we employed the in vitro, in vivo, and patient-derived models to unravel the underlying mechanisms of metabolic crosstalk and proposed the translational strategies. Results: Utilizing newly-developed single-cell FBA method, we illustrated that different cell types have distinct metabolic features. Specifically, tumor cells and macrophages had more active metabolic reprogramming and higher metabolic heterogeneity. Furthermore, we illustrated that a subset of tumor cells having active antioxidant metabolism (featured by the upregulation of GSTP1) and macrophage subset depending on glutamine metabolism (characterized by CCL3+) were negatively and positively predictive of immunotherapy responses, respectively. Mechanistically, GSTP1-mediated excessive consumption of glutamine by tumor cells competitively restrained the intake of glutamine into CCL3+ macrophages to promote their ferroptosis and reduce their infiltration. Clinically, we demonstrated that targeting the GSTP1, which is specifically expressed in tumor cells, remodeled immune-metabolic microenvironment and enhanced immunotherapy efficacy. Furthermore, we established the utility of plasma CCL3 abundance, GSTP1 protein abundance, and CCL3 protein abundance, as robust predictors of response to immunotherapy, in several independent immunotherapy cohorts. Conclusion: Our study presented a comprehensive and multidimensional analysis of the single-cell metabolic landscape. Identifying the crucial metabolic crosstalk remodeling the immune microenvironment, our promising finding highlights the potential significance of modulating cell-cell metabolic interactions in sensitizing TNBC to immunotherapy, providing valuable insights for future therapeutic interventions. Citation Format: Ying Xu, Yi Xiao, Han Wang, Zhimin Shao, Yi-Zhou Jiang. Single-cell metabolic profiling uncovers new precision immunotherapy strategy in triple-negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS03-02.

Current therapeutic targets and promising strategies for triple-negative breast cancer

TNBC refers to breast cancer patients with negative estrogen receptor ER, PR and HER-2. It accounts for about 1520% of all breast cancer cases and has a higher rate of disease recurrence and a worse prognosis than other breast cancer subtypes. Chemotherapy is the most effective treatment now available for TNBC, but it has major adverse consequences on human health. Therefore, the development of new TNBC treatment strategies has become an urgent clinical need. This article first starts with the different subtypes of TNBC, analyzes and summarizes the pathogenesis of TNBC and recent research progress. Secondly, the potential targets of TNBC and the development of targeted treatments based on these targets are analyzed. Finally, it is concluded that it is easier to achieve curative effect by using appropriate specific treatments for different subtypes of TNBC. By summarizing existing treatment regimens and their applicable TNBC subtypes, this article aims to provide new insights for follow-up treatment.

Targeting EMSY-mediated methionine metabolism is a potential therapeutic strategy for triple-negative breast cancer

Cancer stem cells (CSCs) are the most intractable subpopulation of triple-negative breast cancer (TNBC) cells, which have been associated with a high risk of relapse and poor prognosis. However, eradication of CSCs continues to be difficult. Here, we integrate the multiomics data of a TNBC cohort (n= 360) to identify vital markers of CSCs. We discover that EMSY, inducing a BRCAness phenotype, is preferentially expressed in breast CSCs, promotes ALDH+ cells enrichment, and is positively correlated with poor relapse-free survival. Mechanistically, EMSY competitively binds to the Jmjc domain, which is critical for KDM5B enzyme activity, to reshape methionine metabolism, and to promote CSC self-renewal and tumorigenesis in an H3K4 methylation-dependent manner. Moreover, EMSY accumulation in TNBC cells sensitizes them to PARP inhibitors against bulk cells and methionine deprivation against CSCs. These findings indicate that clinically relevant eradication of CSCs could be achieved with a strategy that targets CSC-specific vulnerabilities in amino acid metabolism.

Identification of TFR2 as a novel ferroptosis‑related gene that serves an important role in prognosis and progression of triple‑negative breast cancer.

Effective targeted therapeutic strategies for triple-negative breast cancer (TNBC), the most malignant subtype of breast cancer, are currently lacking. Ferroptosis has been reported to be associated with the onset and advancement of various cancer types, including TNBC. However, there are limited studies on the correlation between TNBC and ferroptosis-related genes. In addition, the potential biomarkers of ferroptosis in TNBC need further investigation. The present study aimed to assess the prognostic role of a novel ferroptosis-related gene signature in the context of TNBC. The signature was established utilizing The Cancer Genome Atlas dataset. This three-gene model [transferrin receptor 2 (TFR2), regulator of G protein signaling 4 and zinc finger protein 36] was developed utilizing least absolute shrinkage and selection operator regression analysis and demonstrated satisfactory predictive performance in TNBC. The area under the curve values of the receiver operating characteristic curves in this model concerning the 1-, 2- and 3-year survival prediction were 0.721, 0.840 and 0.856, respectively. The predictive performance of the model was verified using the TNBC dataset GSE25307. Gene set enrichment analysis (GSEA) demonstrated the enrichment of genes in the low-risk group in a number of important metabolic pathways. Single-sample GSEA demonstrated a variation in the expression levels of immune checkpoint molecules between the high- and low-risk groups. The inhibitory impact of TFR2 knockdown on the proliferative capacity of TNBC cells was verified through in vitro experiments. The data also demonstrated that TFR2 knockdown facilitated the ferroptosis of TNBC cells. Additional assessments indicated that the effects of TFR2 knockdown were partially reversed upon treatment with the ferroptosis inhibitor ferrostatin-1. In conclusion, in the present study, a novel and accurate ferroptosis-related predictive signature was established for TNBC with potential future clinical applications. To the best of our knowledge, the present study is the first to report that TFR2 regulated ferroptosis in TNBC cells in vitro.

SCFβTrCP-mediated degradation of SHARP1 in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer associated with metastasis, high recurrence rate, and poor survival. The basic helix-loop-helix transcription factor SHARP1 (Split and Hairy-related Protein 1) has been identified as a suppressor of the metastatic behavior of TNBC. SHARP1 blocks the invasive phenotype of TNBC by inhibiting hypoxia-inducible factors and its loss correlates with poor survival of breast cancer patients. Here, we show that SHARP1 is an unstable protein that is targeted for proteasomal degradation by the E3 ubiquitin ligase complex SCFβTrCP. SHARP1 recruits βTrCP via a phosphodegron encompassing Ser240 and Glu245 which are required for SHARP1 ubiquitylation and degradation. Furthermore, mice injected with TNBC cells expressing the non-degradable SHARP1(S240A/E245A) mutant display reduced tumor growth and increased tumor-free survival. Our study suggests that targeting the βTrCP-dependent degradation of SHARP1 represents a therapeutic strategy in TNBC.

Molecular targets and therapeutic strategies for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is known for its heterogeneous complexity and is often difficult to treat. TNBC lacks the expression of major hormonal receptors like estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 and is further subdivided into androgen receptor (AR) positive and AR negative. In contrast, AR negative is also known as quadruple-negative breast cancer (QNBC). Compared to AR-positive TNBC, QNBC has a great scarcity of prognostic biomarkers and therapeutic targets. QNBC shows excessive cellular growth and proliferation of tumor cells due to increased expression of growth factors like EGF and various surface proteins. This study briefly reviews the limited data available as protein biomarkers that can be used as molecular targets in treating TNBC as well as QNBC. Targeted therapy and immune checkpoint inhibitors have recently changed cancer treatment. Many studies in medicinal chemistry continue to focus on the synthesis of novel compounds to discover new antiproliferative medicines capable of treating TNBC despite the abundance of treatments currently on the market. Drug repurposing is one of the therapeutic methods for TNBC that has been examined. Moreover, some additional micronutrients, nutraceuticals, and functional foods may be able to lower cancer risk or slow the spread of malignant diseases that have already been diagnosed with cancer. Finally, nanomedicines, or applications of nanotechnology in medicine, introduce nanoparticles with variable chemistry and architecture for the treatment of cancer. This review emphasizes the most recent research on nutraceuticals, medication repositioning, and novel therapeutic strategies for the treatment of TNBC.

Neutrophil extracellular traps mediate TLR9/Merlin axis to resist ferroptosis and promote triple negative breast cancer progression.

Neutrophil and neutrophil extracellular traps (NETs) were reported to be associated with tumor development, but the exact role and concrete mechanisms are still poorly understood, especially in triple negative breast cancer (TNBC). In this study, our results exhibited that NETs formation in TNBC tissues was higher than that in non-TNBC tissues, and NETs formation was distinctly correlated with tumor size, ki67 level and lymph node metastasis in TNBC patients. Subsequent in vivo experiments demonstrated that NETs inhibition could suppress TNBC tumor growth and lung metastasis. Further in vitro experiments uncovered that oncogenic function of NETs on TNBC cells were possibly dependent on TLR9 expression. We also found that neutrophils from peripheral blood of TNBC patients with postoperative fever were prone to form NETs and could enhance the proliferation and invasion of TNBC cells. Mechanistically, we revealed that NETs could interact with TLR9 to decrease Merlin phosphorylation which contributed to TNBC cell ferroptosis resistance. Our work provides a novel insight into the mechanism of NETs promoting TNBC progression and blocking the key modulator of NETs might be a promising therapeutic strategy in TNBC.

Comprehensively analysis of immunophenotyping signature in triple-negative breast cancer patients based on machine learning.

Immunotherapy is a promising strategy for triple-negative breast cancer (TNBC) patients, however, the overall survival (OS) of 5-years is still not satisfactory. Hence, developing more valuable prognostic signature is urgently needed for clinical practice. This study established and verified an effective risk model based on machine learning methods through a series of publicly available datasets. Furthermore, the correlation between risk signature and chemotherapy drug sensitivity were also performed. The findings showed that comprehensive immune typing is highly effective and accurate in assessing prognosis of TNBC patients. Analysis showed that IL18R1, BTN3A1, CD160, CD226, IL12B, GNLY and PDCD1LG2 are key genes that may affect immune typing of TNBC patients. The risk signature plays a robust ability in prognosis prediction compared with other clinicopathological features in TNBC patients. In addition, the effect of our constructed risk model on immunotherapy response was superior to TIDE results. Finally, high-risk groups were more sensitive to MR-1220, GSK2110183 and temsirolimus, indicating that risk characteristics could predict drug sensitivity in TNBC patients to a certain extent. This study proposes an immunophenotype-based risk assessment model that provides a more accurate prognostic assessment tool for patients with TNBC and also predicts new potential compounds by performing machine learning algorithms.

Structural immunoinformatics approach for rational design of a multi-epitope vaccine against triple negative breast cancer

TNBC is a highly malignant breast cancer known for its aggressive behavior affecting young female adults. The standard treatment for TNBC includes surgery, chemotherapy, and radiotherapy, which often have significant side effects. Therefore, novel preventive methods are required to combat TNBC effectively. In this study, we utilized immunoinformatics to construct an in-silico vaccine against TNBC using the TRIM25 molecule via the reverse vaccinology method. Four vaccines were designed by generating T and B-cell epitopes linked with four different linkers. The modeled vaccine was docked and the results showed that vaccine-3 exhibited the highest affinity with the immune receptors. The molecular dynamics results revealed that the binding affinity and stability of Vaccine-3 were greater than those of Vaccine 2 complexes. This study has great potential preventive measures for TNBC, and further research is warranted to evaluate its efficacy in preclinical settings. This study presents an innovative preventive strategy for triple-negative breast cancer (TNBC) through immunoinformatics and reverse vaccinology to develop an in-silico vaccine. Leveraging these innovative techniques offers a novel avenue for combating the complex challenges associated with TNBC. This approach demonstrates considerable potential as a significant breakthrough in preventive measures for this particularly aggressive and malignant form of breast cancer.

PRMT5 reduces immunotherapy efficacy in triple-negative breast cancer by methylating KEAP1 and inhibiting ferroptosis

BackgroundAs an emerging treatment strategy for triple-negative breast cancer (TNBC), immunotherapy acts in part by inducing ferroptosis. Recent studies have shown that protein arginine methyltransferase 5 (PRMT5) has distinct roles...

FSTL1 Suppresses Triple-Negative Breast Cancer Lung Metastasis by Inhibiting M2-like Tumor-Associated Macrophage Recruitment toward the Lungs.

Immune cell infiltration into the tumor microenvironment is associated with cancer prognosis. Tumor-associated macrophages play essential roles in tumor initiation, progression, and metastasis. Follistatin-like protein 1 (FSTL1), a widely expressed glycoprotein in human and mouse tissues, is a tumor suppressor in various cancers and a regulator of macrophage polarization. However, the mechanism by which FSTL1 affects crosstalk between breast cancer cells and macrophages remains unclear. By analyzing public data, we found that FSTL1 expression was significantly low in breast cancer tissues compared to normal breast tissues, and high expression of FSTL1 in patients indicated prolonged survival. Using flow cytometry, we found that total and M2-like macrophages dramatically increased in the metastatic lung tissues during breast cancer lung metastasis in Fstl1+/- mice. Transwell assay in vitro and q-PCR experimental results showed that FSTL1 inhibited macrophage migration toward 4T1 cells by decreasing CSF1, VEGF-α, and TGF-β secretion in 4T1 cells. We demonstrated that FSTL1 inhibited M2-like tumor-associated macrophage recruitment toward the lungs by suppressing CSF1, VEGF-α, and TGF-β secretion in 4T1 cells. Therefore, we identified a potential therapeutic strategy for triple-negative breast cancer.

Inflammatory response-based subtyping and potential therapeutic strategies for triple-negative breast cancer

Objective: Inflammatory response plays a crucial role in the development and treatment of cancer. However, the role of inflammatory response in triple-negative breast cancer (TNBC) remains unclear. Based on the heterogeneity of the inflammatory response, we classified TNBC, elucidated its subtype features, and revealed potential therapeutic strategies. Methods: We established inflammatory response subtyping based on the RNA sequencing data of TNBCs derived from a cohort at the Fudan University Shanghai Cancer Center (FUSCC). Next, we explored the features and potential therapeutic strategies for each subgroup by analyzing transcriptome data. Using a machine-learning method, we validated and generalized the TNBC inflammatory response subtypes in an external dataset. Results: A total of 360 TNBC samples and 88 normal tissues were collected from a cohort at FUSCC. Patients with TNBC were divided into four inflammatory response groups (IRGs) based on the expression of inflammatory response genes: high inflammatory response gene expression with pronounced pyroptosis phenotype and high immune cell infiltration (IRG 1), low inflammatory response gene expression and low immune cell infiltration (IRG 2), ITGB8 specific inflammatory response with a predominant proliferation phenotype (IRG 3), and low M1/M2 ratio with a marked angiogenesis phenotype (IRG 4). Relapse-free survival (RFS) was better in IRG 1 and 2 and worse in IRG 3 and 4. Owing to their poor prognosis, we mainly focused on IRG 3 and IRG 4 to investigate potential treatment strategies. ITGB8 was highly expressed in IRG 3; thus, targeting ITGB8 may be a potential therapeutic strategy for patients in IRG 3. IRG 4 had a lower M1/M2 ratio and a marked angiogenesis phenotype; therefore, therapeutic strategies, such as anti-angiogenesis or M2 to M1 repolarization of macrophages, could be recommended for these patients. Additionally, we validated and generalized the TNBC inflammatory response subtyping in an external dataset using a machine-learning method. Conclusion: TNBC patients with different inflammatory response subtypes have different characteristics and may need subtype-specific treatment strategies.

Postsurgical wound management and prevention of triple-negative breast cancer recurrence with a pryoptosis-inducing, photopolymerizable hydrogel.

Surgical removal remains the predominant treatment strategy for triple-negative breast cancer (TNBC). However, risks that include high locoregional recurrence and remote metastasis threaten patient survival and quality of life after surgery. In this study, a hydrogel based on poly (ethylene glycol) dimethacrylate and sericin methacryloyl was fabricated by photopolymerization to fill the resection cavity and prevent recurrence. The obtained hydrogel exhibited mechanical properties compatible with breast tissue and facilitated postsurgical wound management by promoting tissue regeneration. The DNA methylation inhibitor decitabine (DEC) and poly (lactic-co-glycolic acid)-encapsulated phytochemical gambogic acid (GA) were loaded into the hydrogel. The as-prepared hydrogel promoted fast release of DEC and sustained release of GA, leading to gasdermin E-mediated tumor cell pyroptosis and activating antitumor immune responses. Inducing postsurgical tumor cell pyroptosis inhibited local tumor recurrence and lung metastasis. While the dual-drug-loaded hydrogel system cured less than half of tumor-bearing mice, the cured mice survived for over half a year. These findings indicate that our hydrogel system is an excellent biocompatible platform for postsurgical TNBC therapy.

Exploring immune interactions in triple negative breast cancer: IL-1β inhibition and its therapeutic potential.

Triple negative breast cancer (TNBC) has poor prognosis when compared to other breast cancer subtypes. Despite pre-clinical data supporting an immune targeted approach for TNBCs, immunotherapy has failed to demonstrate the impressive responses seen in other solid tumor malignancies. Additional strategies to modify the tumor immune microenvironment and potentiate response to immunotherapy are needed. In this review, we summarise phase III data supporting the use of immunotherapy for TNBC. We discuss the role of IL-1β in tumorigenesis and summarize pre-clinical data supporting IL-1β inhibition as a potential therapeutic strategy in TNBC. Finally, we present current trials evaluating IL-1β in breast cancer and other solid tumor malignancies and discuss future studies that may provide a strong scientific rationale for the combination of IL-1β and immunotherapy in the neoadjuvant and metastatic setting for people with TNBC.

The Cytoplasmic Region of SARAF Reduces Triple-Negative Breast Cancer Metastasis through the Regulation of Store-Operated Calcium Entry

Triple-negative breast cancer has a poor prognosis and is non-responsive to first-line therapies; hence, new therapeutic strategies are needed. Enhanced store-operated Ca2+ entry (SOCE) has been widely described as a contributing factor to tumorigenic behavior in several tumor types, particularly in breast cancer cells. SOCE-associated regulatory factor (SARAF) acts as an inhibitor of the SOCE response and, therefore, can be a potential antitumor factor. Herein, we generated a C-terminal SARAF fragment to evaluate the effect of overexpression of this peptide on the malignancy of triple-negative breast cancer cell lines. Using both in vitro and in vivo approaches, we showed that overexpression of the C-terminal SARAF fragment reduced proliferation, cell migration, and the invasion of murine and human breast cancer cells by decreasing the SOCE response. Our data suggest that regulating the activity of the SOCE response via SARAF activity might constitute the basis for further alternative therapeutic strategies for triple-negative breast cancer.

Abstract GS5-05: ZNF689 deficiency promotes intratumor heterogeneity and resistance to immune checkpoint blockade in triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) is an aggressive disease characterized by remarkable intratumor heterogeneity (ITH), which poses a significant therapeutic challenge. However, the key determinants and underlying mechanisms of ITH in TNBC remain to be fully elucidated. Methods: We used multi-omics data from our cohort (n = 260) and The Cancer Genome Atlas (n = 134) cohort to comprehensively characterize ITH at the genetic and histologic levels. Transcriptomic differences between high ITH and low ITH tumors were compared to identify the core genes contributing ITH in TNBC. Xenograft models were used to examine the role of key determinants in TNBC ITH. The molecular mechanism was investigated by mass spectrometry, coimmunoprecipitation, pull-down, RNA-seq, long interspersed element-1 (LINE-1) reporter, ATAC-seq, luciferase reporter assays, chromatin immunoprecipitation, flow cytometry and coculture assay. Results: We found that high ITH was associated with poor patient survival and immune checkpoint blockade (ICB) resistance, which were validated in four independent ICB-treated trials. Further analysis indicated zinc finger protein 689 (ZNF689) deficiency as an important determinant of TNBC ITH. Mechanistically, the ZNF689-TRIM28 complex directly bound to the promoter of LINE-1, inducing H3K9me3-mediated transcriptional silencing. ZNF689 deficiency reactivated LINE-1 retrotransposition to exacerbate genomic instability, which promoted ITH. ZNF689 deficiency-induced ITH inhibited antigen presentation and CD8+ T cell infiltration, leading to ICB resistance. Pharmacological inhibition of LINE-1 retrotransposition reduced ITH, augmented antitumor immunity, and eventually sensitized ZNF689-deficient tumors to ICB. Consistently, ZNF689 expression positively correlated with favorable prognosis and ICB responsiveness in clinical samples. Conclusions: Our study uncovers a new mechanism underlying ZNF689 deficiency-induced ITH and suggests LINE-1 inhibition combined with ICB as a novel treatment strategy in TNBC. Citation Format: Li-Ping Ge, Xi Jin, Gen-Hong Di, Yi-Zhou Jiang, Zhi-Ming Shao. ZNF689 deficiency promotes intratumor heterogeneity and resistance to immune checkpoint blockade in triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-05.

Combination immunotherapy strategies for triple-negative breast cancer: current progress and barriers within the pharmacological landscape

Introduction : Triple-negative breast cancer (TNBC) is a breast cancer subtype characterized by poorer prognosis. Despite that TNBC can display immunogenic features, anti-PD(L)1 monotherapy strategies have resulted in disappointing results, underscoring the need to optimize their use in TNBC. Among many, combining immunotherapy with other agents to exploit the synergistic effect of different drugs has been explored. Such a combination approach led to the approval of immune checkpoint inhibitors (ICIs) plus chemotherapy in both metastatic and early setting. Nevertheless, primary or secondary resistance to ICIs remains a major hurdle to overcome, with a major need to explore novel combination strategies. Areas covered : This review summarizes the biological rationale, current evidence, and ongoing clinical trials of immunotherapy combined with novel immunotherapeutics, chemotherapy, targeted compounds, and antibody-drug conjugates. Expert opinion : The treatment landscape of TNBC is in continuous changes. ICIs are now part of the clinical practice; however, several unmet needs still remain, including the need to overcome resistance and prolong benefit of ICIs. Exploiting synergism between different agent has emerged as an attractive strategy to extend the benefit obtained with ICIs. The goal of future research will be to unveil the mechanisms underlying resistance to ICIs and to identify better biomarkers for patient selection.

Enhanced antitumor effect of doxorubicin through active-targeted nanoparticles in doxorubicin-resistant triple-negative breast cancer

Breast cancer is the most common cancer in women worldwide, and the incidence and mortality rates have been increasing. Chemotherapy remains the main treatment strategy for triple-negative breast cancer (TNBC). However, multidrug resistance often affects the efficiency of chemotherapy and is the main reason for the failure of current clinical cancer treatments in patients with TNBC. Therefore, we developed a nanocarrier with biodegradable polymer materials and encapsulated a clinical chemotherapeutic drug to form an active targeting nanoparticle drug delivery system. In this study, the biopolymers fucoidan (FD) and arginine-gelatin (Arg-GL) were used to synthesize nanoparticles through electrostatic forces and to encapsulate the chemotherapeutic drug doxorubicin (Dox). Our study demonstrated that the Dox-loaded FD/Arg-GL nanoparticles exhibited high drug loading capacity and pH-responsive characteristics. The results of in vitro experiments showed that the nanoparticles actively targeted P-selectin expressed by cancer cells, thereby enhancing the anticancer effect and inhibiting the migration and invasion of Dox-resistant TNBC cells. Moreover, in vivo studies further confirmed the antitumor activity of the nanoparticles, as they enabled the drug to accumulate at the tumor site. In conclusion, Dox-loaded FD/Arg-GL nanoparticles offer a potential therapeutic strategy for drug-resistant TNBC.

MiR-589-5p Inhibits Cell Proliferation by Targeting Histone Deacetylase 3 in Triple Negative Breast Cancer

Histone deacetylase 3 (HDAC3) is a potential oncogene that is significantly up-regulated in patients with breast cancer. MicroRNAs (miRs) are a group of small non-coding and regulatory RNAs which have recently been proposed as promising molecules for breast cancer target therapy. In the current study, we investigated the impact of miR-589-5p/ HDAC3 axis on cancer cell development in triple negative breast cancer (TNBC) cells. In-silico analysis determined that miR-589-5p potentially targets HDAC3. We evaluated the HDAC3 and mir-589-5p expression levels in clinical samples and breast cancer cell lines including MDA-MB-231, MDA-MB-468, MCF-7 and MCF-10A. HDAC3 was knocked out to investigate its role on cancer cell progression. Anti-cancerous role of the miR-589-5p was assessed using an expression vector. We evaluated possible alteration in the cell cycle progression, cell viability and cell proliferation, after transient transfection. HDAC3 was over-expressed in TNBC clinical samples and breast cancer cell lines compared to non-cancerous controls while miR-589-5p was down regulated in cancer cells. Suppression of HDAC3 decreased the cell viability, cell proliferation and colony formation. Similar results were observed after over-expression of the miR-589-5p. Dual-Luciferase reporter assay confirmed the direct targeting of HDAC3 by miR-589-5p. Our results showed that miR-589-5p mediates its anti-proliferative effects on breast cancer cells via targeting HDAC3. These findings suggest that the miR-589-5p/ HDAC3 axis could be considered as a possible therapeutic strategy in TNBC.