Target For Triple-negative Breast Cancer Research Articles

Network Pharmacology and In Silico Elucidation of Phytochemicals Extracted from Ajwa Dates (Phoenix dactylifera L.) to Inhibit Akt and PI3K Causing Triple Negative Breast Cancer (TNBC).

About 10-15% of all breast cancers comprise triple-negative breast cancer (TNBC), defined as cancer cells that lack receptors for the ER, PR, and HER2 protein receptors. Due to the absence of these receptors, treating TNBC using conventional chemotherapy is challenging and, therefore, requires the discovery of novel chemotherapeutic agents derived from natural sources. The current work was intended to study the potential phytochemicals of Ajwa dates (Phoenix dactylifera L.) with the predicted potential targets (namely, Akt and PI3K) to determine possible TNBC inhibitors. We harnessed network pharmacology, molecular docking, drug-likeness studies, Molecular Dynamics (MD) simulation, and binding free energy (MM-GBSA) calculation to get phytochemicals with potential effects against TNBC. Firstly, molecular docking was performed on 125 phytochemicals against the Akt and PI3K proteins utilizing PyRx. Then, the phytochemicals with the highest binding affinity (≤ -8.1 kcal/mol) were examined for in silico drug-likeness and toxicity profiles. Finally, phytochemicals with optimal druglikeness and toxicity profiles were studied by Molecular Dynamics (MD) simulation and binding free energy (MM-GBSA) to identify compounds that can form stable complexes. The results of the network pharmacology revealed that the Akt and PI3K proteins are potential targets of TNBC for the phytochemicals of Phoenix dactylifera L. used in this study. The outcomes of molecular docking displayed that among 125 phytochemicals, 42 of them (with a binding affinity ≤ -8.1 kcal/mol) have potentially inhibiting effects on both proteins PI3K and Akt expressed in TNBC. Then, the results of in silico drug-likeness identified seven phytochemicals with optimal pharmacokinetic profiles. Furthermore, toxicity studies showed that three phytochemicals (namely, Chrysoeriol, Daidzein, and Glycitein) did not cause any toxicities. Finally, the Molecular Dynamics (MD) simulation studies and binding free energy (MM-GBSA) verified that Daidzein stayed within the binding cavities of both proteins (Akt and PI3K) by establishing a stable protein-ligand complex during simulation. Taken together, the current work emphasizes the potential effects of Daidzein from Phoenix dactylifera L. against TNBC, and it can be further studied to establish it as a standard chemotherapy for TNBC.

Abstract A009: Genetic disruption of CAPNS1 impedes triple-negative breast cancer metastasis: A case for selective calpain-1/2 inhibitors

Abstract Calpains are a family of 15 calcium-activated cysteine proteases that have emerged as potential therapeutic targets in triple negative breast cancer (TNBC). They regulate the function of their substrates via limited proteolytic processing and are involved in both pro- and anti-apoptotic signaling pathways, as well as membrane-cytoskeletal remodeling events associated with cell migration and invasion. The most well-understood members of the calpain family are the classical calpain-1 and calpain-2 isoforms, which are ubiquitously expressed heterodimers each consisting of a large catalytic subunit, encoded by the capn1 and capn2 genes, respectively, and a common small regulatory subunit encoded by capns1. Overexpression of calpain-1 and calpain-2 has been associated with shorter survival in HER2+ breast cancer and TNBC, respectively. We hypothesize that inhibition of calpain-1 and calpain-2 may be exploited to improve tumor response to cytotoxic chemotherapy and suppress metastasis. CRISPR-Cas9 mediated knockout of capns1 in AC2M2 mouse mammary carcinoma cells, which results in a loss of both calpain-1 and calpain-2 activity, disrupts migration and invasion in vitro and impedes lung metastasis in tail vein and orthotopic engraftment mouse models. Calpain knockout also sensitizes AC2M2 cells to the microtubule stabilizing drug paclitaxel, and preliminary results suggest that cancer cell intrinsic calpain depletion may prevent neoadjuvant chemotherapy-induced metastasis. To explore potential off-target effects associated with systemic calpain inhibition, we have established a novel transgenic mouse with conditional deletion of capns1 in its hematopoietic stem cell lineage. By comparing the immune profiles of wild-type and capns1 knockout mice, we aim to better understand how calpain inhibitors will affect various immune cell populations and their respective functions. We plan to extend this understanding to anticancer immunity by conducting tumor immunophenotyping experiments in syngeneic orthotopic engraftment models using wild-type and capns1 knockout mice. At present, no clinically relevant calpain inhibitors are available. However, using genetic approaches, we have validated calpain-1 and calpain-2 as relevant therapeutic targets in TNBC, providing rationale for the development of selective calpain inhibitors. Citation Format: Danielle Harper, Ivan Shapovalov, Samantha Cockburn, Jenny Min, Yan Gao, Peter A. Greer. Genetic disruption of CAPNS1 impedes triple-negative breast cancer metastasis: A case for selective calpain-1/2 inhibitors [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr A009.

FAM83H regulated by glis3 promotes triple-negative breast cancer tumorigenesis and activates the NF-κB signaling pathway.

Triple-negative breast cancer (TNBC) is a highly aggressive and invasive form of breast cancer (BC) with a high mortality rate and a lack of effective targeted drugs. Family with sequence similarity 83 member H (FAM83H) is critically implicated in tumorigenesis. However, the potential role of FAM83H in TNBC remains elusive. Here, we discovered that FAM83H exhibited high expression in tumor tissues of patients with TNBC and was associated with TNM stage. Gain- or loss-of-function experiments were conducted to explore the biological role of FAM83H in TNBC. Subsequently, functional enrichment analysis confirmed that FAM83H overexpression promoted TNBC cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT), accompanied by upregulation of cyclin E, cyclin D, Vimentin, N-cadherin and Slug. As observed, FAM83H knockdown showed anti-cancer effects, such as fostering apoptosis and inhibiting tumorigenicity and metastasis of TNBC cells. Mechanistically, FAM83H activated the NF-κB signaling pathway. Moreover, a dual-luciferase reporter assay demonstrated that GLIS family zinc finger 3 (GLIS3) bound to the promoter of FAM83H and enhanced its transcription. Notably, overexpression of GLIS3 significantly stimulated TNBC cell proliferation and invasion, and all of this was reversed by rescue experiments involving the knockdown of FAM83H. Overall, FAM83H exacerbates tumor progression, and in-depth understanding of FAM83H as a therapeutic target for TNBC will provide clinical translational potential for intervention therapy.

Enhancing radiotherapy in triple-negative breast cancer with hesperetin-induced ferroptosis via AURKA targeting nanocomposites

Triple-negative breast cancer (TNBC) is an aggressive cancer type that lacks targeted treatment options. Ferroptosis, a novel therapeutic strategy, induces cell death by disrupting the oxidative-reductive balance. Hesperetin, a potential TNBC therapeutic drug, has unidentified regulatory targets. The objective of this study was to explore the potential targets of hesperetin in TNBC and investigate whether the nanocomposites carrier hesperetin-loaded ferroptosis-inducing nanocomposites (HFPN), which activates ferroptosis, can enhance the anti-tumor efficacy of hesperetin. Bioinformatics methods were employed to screen hesperetin targets in TNBC, and a molecular docking model between hesperetin and the core target aurora kinase A (AURKA) was successfully constructed. The stability and anti-tumor activity of HFPN were validated in cell and mouse models, including tumor suppression and increased radiation sensitivity. These results suggest that HFPN can regulate the core target AURKA in TNBC, disrupt tumor oxidative-reductive balance, promote ferroptosis in tumor cells, and ultimately enhance the effectiveness of radiation therapy for TNBC.Graphical abstract

CD74 promotes the formation of an immunosuppressive tumor microenvironment in triple-negative breast cancer in mice by inducing the expansion of tolerogenic dendritic cells and regulatory B cells.

CD74 is a cell-surface receptor for the cytokine macrophage migration inhibitory factor (MIF). MIF binding to CD74 induces a signaling cascade resulting in the release of its cytosolic intracellular domain (CD74-ICD), which regulates transcription in naïve B and chronic lymphocytic leukemia (CLL) cells. In the current study, we investigated the role of CD74 in the regulation of the immunosuppressive tumor microenvironment (TME) in triple-negative breast cancer (TNBC). TNBC is the most aggressive breast cancer subtype and is characterized by massive infiltration of immune cells to the tumor microenvironment, making this tumor a good candidate for immunotherapy. The tumor and immune cells in TNBC express high levels of CD74; however, the function of this receptor in the tumor environment has not been extensively characterized. Regulatory B cells (Bregs) and tolerogenic dendritic cells) tol-DCs (were previously shown to attenuate the antitumor immune response in TNBC. Here, we demonstrate that CD74 enhances tumor growth by inducing the expansion of tumor-infiltrating tol-DCs and Bregs. Utilizing CD74-KO mice, Cre-flox mice lacking CD74 in CD23+ mature B cells, mice lacking CD74 in the CD11c+ population, and a CD74 inhibitor (DRQ), we elucidate the mechanism by which CD74 inhibits antitumor immunity. MIF secreted from the tumor cells activates CD74 expressed on DCs. This activation induces the binding of CD74-ICD to the SP1 promotor, resulting in the up-regulation of SP1 expression. SP1 binds the IL-1β promotor, leading to the down-regulation of its transcription. The reduced levels of IL-1β lead to decreased antitumor activity by allowing expansion of the tol-DC, which induces the expansion of the Breg population, supporting the cross-talk between these 2 populations. Taken together, these results suggest that CD74+ CD11c+ DCs are the dominant cell type involved in the regulation of TNBC progression. These findings indicate that CD74 might serve as a novel therapeutic target in TNBC.

Overexpression of SLAP2 inhibits triple-negative breast cancer progression by promoting macrophage M1-type polarization

Breast cancer is the most common malignant tumor in women, and triple-negative breast cancer (TNBC) is a specific subtype of breast cancer characterized by high invasiveness, high metastatic potential, ease of recurrence, and poor prognosis. Src-like adaptor protein 2 (SLAP2), which can be involved in the regulation of multiple signaling pathways, may be a key target for TNBC. The aim of this study was to investigate the effect of overexpression of SLAP2 on TNBC and to explore the underlying mechanisms. First, we constructed and transfected SLAP2 overexpressing lentivirus based on MDA-MB-231 human TNBC cell line, screened for differential downstream target genes in combination with mRNA high-throughput sequencing (RNA-Seq), and predicted their functions and enriched pathways in conjunction with bioinformatics analysis. The effects of SLAP2 overexpression on macrophage polarization, as well as on tumor proliferation and apoptosis, were assessed by tail vein injection of a stable transfection line of 4T1 cells transfected with SLAP2 overexpressing lentivirus. The effect of SLAP2 on macrophage polarization was assessed by inducing M1/M2 polarization and transfecting SLAP2 overexpressing lentivirus. Meanwhile, a transwell co-culture system was constructed between differently treated macrophages and 4T1 cells to assess the effect of SLAP2 overexpression on the malignant behavior of the cells via macrophage polarization. Overexpression of SLAP2 revealed 179 genes up-regulated and 74 genes down-regulated by mRNA high-throughput sequencing, and the enriched functions and pathways of differential genes were mainly related to immunity response. In vivo experiments revealed that overexpression of SLAP2 inhibited the growth of tumor in nude mice, decreased the expression of ki67 in tumor tissues, and increased the rate of apoptosis in tumor tissues. Meanwhile, we found that overexpression of SLAP2 promoted macrophage polarization toward M1 type and inhibited M2 type polarization in tumors. In vitro experiments further verified its effect on M1/M2 polarization by transfecting SLAP2 overexpressing lentivirus. By transwell co-culture system, we further demonstrated that overexpression of SLAP2 inhibits cell proliferation and invasion, promotes apoptosis, up-regulates the expression of Bax in cells, and down-regulates the expression of Bcl-2 in cells by promoting macrophage M1-type polarization. Overexpression of SLAP2 inhibits TNBC progression by promoting macrophage M1-type polarization.

Amine-Terminated Silver Nanoparticles Exhibit Potential for Selective Targeting of Triple-Negative Breast Cancer

Silver nanoparticles (AgNPs) demonstrate potential in treating aggressive cancers such as triple-negative breast cancer (TNBC) in preclinical models. To further the development of AgNP-based therapeutics for clinical use, it is essential to clearly define the specific physicochemical characteristics of the nanoparticles and connect these properties to biological outcomes. This study addresses this knowledge gap through detailed investigations into the structural and surface functional relationships, exploring the mechanisms, safety, and efficacy of AgNPs in targeting TNBC. The surface functionality of nanoparticles is crucial not only for their internalization into cancer cells but also for enhancing their toxicity toward tumor cells. Although the nanoparticles internalized into cancer cells, they failed to exhibit their full toxicity against the cancer. Herein we report a solvent-assisted synthesis amine, mercaptohexanol and bifunctional silver nanoparticles and performing comparative study to understand their selectivity and toxicity toward TNBC cells. The nanoparticles are fully characterized by UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and dynamic light scattering measurement (DLS). The synthesis method achieves an extremely high yield and surface coating ratio of synthesized colloidal AgNPs. Our findings reveal that the amine-capped AgNPs exhibit significant selective toxicity against TNBC cell lines MCF7 and MDA-MB-231 at a concentration of 40 µg/mL without affecting normal breast cell lines MCF10A. This study underscores the potential of functionalized AgNPs in developing safe and targeted therapeutic approaches for treating aggressive cancers like TNBC, laying the groundwork for future clinical advancements.

Identification of Tumor Microenvironment Genes in Triple Negative Breast Cancer

Introduction: In triple negative breast cancer (TNBC) an aggressive molecular subtype of breast cancer, tumor microenvironment (TME) is a complex and dynamic ecosystem that plays a pivotal role in the tumor growth, disease metastasis, immune escape and therapeutic resistance. Understanding the TME holds significant potential for identification of biomarkers of TME and pathways associated as therapeutic targets for improving survival in patients with TNBC. Materials and Methods: The current study evaluated 682 TME related genes by Array Comparative Genomic Hybridization (aCGH) in 55 patients with TNBC. Results: Gain/amplification of 411 genes and loss/deletion of 196 genes of tumor microenvironment was observed in TNBC. Further PPI network analysis using Cytoscape plugin and degree ranking method identified GNAQ, MAPK1, AKT1, HRAS, and MAPK3 are five key up-regulated hub genes, and IL4, LCK, STAT6, MTOR, and NFKBIA are five key down-regulated hub genes. Conclusion: Gain/amplification of GNAQ and loss/deletion of LCK leads to activation of PI3K/AKT/mTOR and RAS/MEK pathways which can be targeted to improve survival of patients with TNBC. However, validation of these pathway genes by RT-PCR or protein expression by immunohistochemistry are further needed to establish these biomarkers as therapeutic targets for TNBC.

Integrated analysis reveals prognostic correlation and immune characteristics of a tumor-associated macrophage-based risk signature in triple-negative breast cancer.

Tumor-associated macrophages play a critical role in the progression and immune response of triple-negative breast cancer (TNBC). Our study aimed to explore the characteristics of tumor-associated macrophages (TAMs) in TNBC, construct a risk signature associated with TAM clusters, and verify its relationship with prognosis and immune-related characteristics. Firstly, we identified four TAM clusters and determined prognosis-related clusters in TNBC based on the single-cell RNA sequencing (scRNA-seq) data. Subsequently, the TAM-related prognostic genes were obtained by the univariate Cox regression analysis and an 8-gene risk signature was then constructed by least absolute shrinkage and selection operator (LASSO) regression based on these TAM-related prognostic genes. Analyses of immune characteristics showed a significant association between the signature with stromal and immune scores, as well as some immune cells. Multivariate analysis revealed that the risk signature was an independent prognostic factor for TNBC, and its value in predicting immunotherapeutic outcomes was also confirmed. A novel nomogram integrating the stage and TAM-based risk signature was constructed, which exhibited favorable predictability and reliability in the prognosis prediction of TNBC. Finally, the increasing expression of GPR34 which is one of the eight hub genes was explored in TNBC by experiments including reverse-transcriptase polymerase chain reaction, western blot, and immunohistochemistry. Our study may provide unique insights into obtaining independent prognostic factors, improving immunotherapeutic strategies, and identifying effective therapeutic targets for TNBC.

Integrating network pharmacology, molecular docking and experimental verification to explore the therapeutic effect and potential mechanism of nomilin against triple-negative breast cancer

BackgroundNomilin is a limonoid compound known for its multiple biological activities, but its role in triple negative breast cancer (TNBC) remains unclear. This study aims to uncover the potential therapeutic effect of nomilin on TNBC and elucidate the specific mechanism of its action.MethodsWe employed weighted gene co-expression network analysis (WGCNA), differential expression analysis, and the GeneCards database to identify potential targets for TNBC. Simultaneously, we utilized the Swiss Target Prediction, ChEMBL, and STITCH databases to identify potential targets of nomilin. The core targets and mechanisms of nomilin against TNBC were predicted through protein-protein interaction (PPI) network analysis, molecular docking, and enrichment analysis. The results of the network pharmacology were corroborated by conducting experiments.ResultsA total of 17,204 TNBC targets were screened, and 301 potential targets of nomilin were identified. Through the PPI network, eight core targets of nomilin against TNBC were pinpointed, namely BCL2, Caspase3, CyclinD1, EGFR, HSP90AA1, KRAS, PARP1, and TNF. Molecular docking, molecular dynamics simulation and proteome microarray revealed that nomilin exhibits strong binding activity to these core proteins. Enrichment analysis results indicated that the anti-TNBC effect of nomilin is associated with PI3K/Akt pathway. In vitro and in vivo experiments have demonstrated that nomilin inhibits TNBC cell proliferation and migration while promoting cell apoptosis through the PI3K/Akt pathway.ConclusionFor the first time, the research effectively discovered the objectives and mechanisms of nomilin in combating TNBC using network pharmacology, molecular docking, molecular dynamics simulation, proteome microarray and experimental confirmation, presenting a hopeful approach for treating TNBC.Graphical

MIR4435-2HG: A novel biomarker for triple-negative breast cancer diagnosis and prognosis, activating cancer-associated fibroblasts and driving tumor invasion through EMT associated with JNK/c-Jun and p38 MAPK signaling pathway activation

BackgroundBreast cancer has the highest incidence rate and causes the most fatalities among all female cancers worldwide. Triple-negative breast cancer (TNBC) is known for its strong invasiveness and higher rates of recurrence. In this research, we aimed to identify MIR4435-2HG as a promising long non-coding RNA (lncRNA) biomarker and therapeutic target for TNBC. MethodsUtilizing clinicopathological information and transcriptome data from The Cancer Genome Atlas (TCGA) database, we assessed the clinical relevance of MIR4435-2HG in breast cancer through univariate and multivariate COX regression, receiver operating characteristic (ROC) analysis, as well as Kaplan-Meier survival analysis. To investigate the biological role of MIR4435-2HG in TNBC, we conducted gene set enrichment analysis (GSEA), as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Additionally, we constructed and validated a nomogram to predict disease-free survival (DFS). Both the R package “pRRophetic” and the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm were employed to forecast the sensitivity to different therapeutics between the high- and low-MIR4435-2HG groups. We employed single-cell RNA sequencing analysis and tumor microenvironment infiltration analysis to investigate the potential involvement of MIR4435-2HG in the TNBC tumor microenvironment. Cellular biological behaviors were assessed utilizing CCK-8, transwell assays, and wound-healing assays. Furthermore, we performed RNA-seq, qRT-PCR, and western blotting analyses to elucidate and confirm the specific mechanisms underlying the role of MIR4435-2HG in TNBC. ResultsIn our study, we have identified MIR4435-2HG as a significant diagnostic and prognostic factor for TNBC. We observed that MIR4435-2HG is widely expressed and might have a significant impact on the reshaping of the TNBC tumor microenvironment. Patients with TNBC in the high-MIR4435-2HG group may show reduced sensitivity to cisplatin, doxorubicin, and gemcitabine and have an increased propensity for immune escape. Knockdown of MIR4435-2HG inhibits cancer-associated fibroblasts (CAFs) activation. Notably, MIR4435-2HG predominantly enhances the migratory and invasive capabilities of TNBC cells through the epithelial-mesenchymal transition (EMT) process. Mechanistically, we validated that MIR4435-2HG activates the JNK/c-Jun and p38 non-classical MAPK signaling pathway in TNBC cells. ConclusionsOur findings highlight the significant potential of MIR4435-2HG as a highly promising biomarker for TNBC. Targeting MIR4435-2HG could represent an appealing therapeutic approach for TNBC.

In vivo CRISPR screens identify Mga as an immunotherapy target in triple-negative breast cancer

Immune evasion is not only critical for tumor initiation and progression, but also determines the efficacy of immunotherapies. Through iterative in vivo CRISPR screens with seven syngeneic tumor models, we identified core and context-dependent immune evasion pathways across cancer types. This valuable high-confidence dataset is available for the further understanding of tumor intrinsic immunomodulators, which may lead to the discovery of effective anticancer therapeutic targets. With a focus on triple-negative breast cancer (TNBC), we found that Mga knock-out significantly enhances antitumor immunity and inhibits tumor growth. Transcriptomics and single-cell RNA sequencing analyses revealed that Mga influences various immune-related pathways in the tumor microenvironment. Our findings suggest that Mga may play a role in modulating the tumor immune landscape, though the precise mechanisms require further investigation. Interestingly, we observed that low MGA expression in breast cancer patients correlates with a favorable prognosis, particularly in those with active interferon-γ signaling. These observations provide insights into tumor immune escape mechanisms and suggest that further exploration of MGA's function could potentially lead to effective therapeutic strategies in TNBC.

Unconventional p65/p52 NF-κB module regulates key tumor microenvironment-related genes in breast tumor-associated macrophages (TAMs)

The complex heterogeneity of tumor microenvironment (TME) of triple-negative breast cancer (TNBC) presents a significant obstacle to cytotoxic immune response and successful treatment, building up one of the most hostile oncological phenotypes. Among the most abundant TME components, tumor-associated macrophages (TAMs) have pivotal pro-tumoral functions, involving discordant roles for the nuclear factor kappa-B (NF-κB) transcription factors and directing to higher levels of pathway complexity.In both resting macrophages and TAMs, we recently revealed the existence of the uncharacterized NF-κB p65/p52 dimer. In the present study, we demonstrated its enhanced active nuclear localization in TAMs and validated selected immune target genes as directly regulated by dimer binding on DNA sequences.We demonstrated by ChIP-qPCR that p65/p52 enrichment on HSPG2 and CSF-1 regulatory regions is strictly dependent on macrophage polarization and tumor environment.Our data provide novel mechanisms of transcriptional regulation in TAMs, orchestrated by the varied and dynamic nature of NF-κB combinations, which needs to be considered when targeting this pathway in cancer therapies.Our results offer p65/p52, together with identified regulatory regions on genes impacting macrophage behavior and tumor biology, as novel molecular targets for TNBC, aimed at modulating TAMs functions towards anti-tumoral phenotypes and thus improving cancer treatment outcomes.

CD8+ T cell‑related KCTD5 contributes to malignant progression and unfavorable clinical outcome of patients with triple‑negative breast cancer.

Triple‑negative breast cancer (TNBC) is a highly aggressive and heterogeneous subtype of breast cancer that lacks expression of estrogen receptor, progesterone receptor, and HER2, making it more challenging to treat with targeted therapies. The present study aimed to identify CD8+ T cell‑associated genes, which could provide insight into the mechanisms underlying TNBC to facilitate developing novel immunotherapies. TNBC datasets were downloaded from public databases including The Cancer Genome Atlas, Molecular Taxonomy of Breast Cancer International Consortium, and Gene Expression Omnibus. Candidate genes were identified integrating weighted gene co‑expression network analysis (WGCNA), differential gene expression, protein‑protein‑interaction network construction and univariate Cox regression analysis. Kaplan‑Meier survival, multivariate Cox regression and receiver operating characteristic analysis were performed to evaluate the prognostic value of hub genes. Knockdown experiments, alongside wound healing, Cell Counting Kit‑8 and Transwell migration and invasion assays were performed. In total, seven gene modules were associated with CD8+ T cells using WGCNA, among which potassium channel tetramerization domain 5 (KCTD5) was significantly upregulated in TNBC samples and was associated with poor prognosis. KCTD5 expression inversely associated with infiltration ratios of 'Macrophages M1', 'Plasma cells', and 'γδ T cells', but positively with 'activated Mast cells', 'Macrophages M0', and 'Macrophages M2'. As an independent prognostic indicator for TNBC, KCTD5 was also associated with drug sensitivity and the expression of programmed cell death protein 1, Cytotoxic T‑Lymphocyte‑Associated Protein 4 (CTLA4), CD274), Cluster of Differentiation 86 (CD86), Lymphocyte‑Activation Gene 3 (LAG3), T Cell Immunoreceptor with Ig and ITIM Domains (TIGIT). Knockdown of KCTD5 significantly inhibited viability, migration and invasion of TNBC cells in vitro. KCTD5 was suggested to impact the tumor immune microenvironment by influencing the infiltration of immune cells and may serve as a potential therapeutic target for TNBC.

Therapeutic Potential of PLK1, KIF4A, CDCA5, UBE2C, CDT1, SKA3, AURKB, and PTTG1 Genes in Triple-Negative Breast Cancer: Correlating Their Expression with Sensitivity to GSK 461364 and IKK 16 Drugs.

The treatment of triple-negative breast cancer (TNBC) has been associated with challenges due to the lack of expression of ER, PR, and HER2 receptors in tumor cells. This study aimed to identify genes with potential therapeutic targets in TNBC. Data from the cancer genome atlas regarding breast cancer (BC) were downloaded. After initial preprocessing, cancer samples were categorized into four groups: TNBC, HER2-positive, luminal A, and luminal B. Gene expression differences between these groups were calculated, focusing on genes that showed differential expression in TNBC. A protein-protein interaction network was conducted to identify hub genes among the candidate genes related to TNBC. The protein expression of candidate genes was assessed using immunohistochemistry data from the human protein atlas. Drug resistance and sensitivity associated with hub genes were identified using data from PharmacoDB. TNBC samples and the RT-qPCR method were used to confirm the results. Our findings revealed that eight genes, namely PLK1, KIF4A, CDCA5, UBE2C, CDT1, SKA3, AURKB, and PTTG1, had significant upregulation at the RNA level in TNBC subgroup compared to other subgroups and could be considered hub genes in TNBC. Compared to other subgroups, their expression level in TNBC samples had high sensitivity and specificity. RT-qPCR results also demonstrated a significant increase in levels of SKA3 and PTTG1 in the TNBC compared to healthy tissue and other subgroups. The protein expression of these genes was notably high in some BC samples. PharmacoDB data showed that some candidate genes were closely linked to drug sensitivity of GSK 461364 and IKK 16. The results of this study showed a significant increase in the expression level of PLK1, KIF4A, CDCA5, UBE2C, CDT1, SKA3, AURKB, and PTTG1 in TNBC compared to other BC subgroups. These genes show considerable promise as therapeutic targets for the TNBC subgroup.

SAHA potentiates the activity of repurposed drug promethazine loaded PLGA nanoparticles in triple-negative breast cancer cells.

Triple-negative breast cancer (TNBC) is considered the most aggressive form of breast cancer owing to the negative expression of targetable bioreceptors. Epithelial to mesenchymal transition (EMT) associated with metastatic abilities is its critical feature. As an attempt to target TNBC, nanotechnology was utilised to augment the effects of drug repurposing. Concerning that, a combination therapeutic module was structured with one of the aspects being a repurposed antihistamine, promethazine hydrochloride loaded PLGA nanoparticles. The as-synthesized nanoparticles were 217 nm in size and fluoresced at 522 nm, rendering them suitable for theranostic applications too. The second feature of the module was a common histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), used as a form of pre-treatment. Experimental studies demonstrated efficient cellular internalisation and significant innate anti-proliferative potential. The use of SAHA sensitised the cells to the drug loaded nanoparticle treatment. Mechanistic studies showed increase in ROS generation, mitochondrial dysfunction followed by apoptosis. Investigations into protein expression also revealed reduction of mesenchymal proteins like vimentin by 1.90 fold; while increase in epithelial marker like E-Cadherin by 1.42 fold, thus indicating an altered EMT dynamics. Further findings also provided better insight into the benefits of SAHA potentiated targeting of tumor spheroids that mimic solid tumors of TNBC. Thus, this study paves the avenue to a more rational translational validation of combining nanotherapeutics with drug repurposing.

Low-Molecular Weight Cyclin E Confers a Vulnerability to PKMYT1 Inhibition in Triple-Negative Breast Cancer.

Cyclin E is a regulatory subunit of CDK2 that mediates S phase entry and progression. The cleavage of full-length cyclin E (FL-cycE) to low-molecular weight isoforms (LMW-E) dramatically alters substrate specificity, promoting G1-S cell cycle transition and accelerating mitotic exit. Approximately 70% of triple-negative breast cancers (TNBC) express LMW-E, which correlates with poor prognosis. PKMYT1 also plays an important role in mitosis by inhibiting CDK1 to block premature mitotic entry, suggesting it could be a therapeutic target in TNBC expressing LMW-E. In this study, analysis of tumor samples of patients with TNBC revealed that coexpression of LMW-E and PKMYT1-catalyzed CDK1 phosphorylation predicted poor response to neoadjuvant chemotherapy. Compared with FL-cycE, LMW-E specifically upregulates PKMYT1 expression and protein stability, thereby increasing CDK1 phosphorylation. Inhibiting PKMYT1 with the selective inhibitor RP-6306 (lunresertib) elicited LMW-E-dependent antitumor effects, accelerating premature mitotic entry, inhibiting replication fork restart, and enhancing DNA damage, chromosomal breakage, apoptosis, and replication stress. Importantly, TNBC cell line xenografts expressing LMW-E showed greater sensitivity to RP-6306 than tumors with empty vector or FL-cycE. Furthermore, RP-6306 exerted tumor suppressive effects in LMW-E transgenic murine mammary tumors and patient-derived xenografts of LMW-E-high TNBC but not in the LMW-E null models examined in parallel. Lastly, transcriptomic and immune profiling demonstrated that RP-6306 treatment induced interferon responses and T-cell infiltration in the LMW-E-high tumor microenvironment, enhancing the antitumor immune response. These findings highlight the LMW-E/PKMYT1/CDK1 regulatory axis as a promising therapeutic target in TNBC, providing the rationale for further clinical development of PKMYT1 inhibitors in this aggressive breast cancer subtype. Significance: PKMYT1 upregulation and CDK1 phosphorylation in triple-negative breast cancer expressing low-molecular weight cyclin E leads to suboptimal responses to chemotherapy but sensitizes tumors to PKMYT1 inhibitors, proposing a personalized treatment strategy.

High Glycolytic Activity Signature Reveals CCNB2 as a Key Therapeutic Target in Triple-Negative Breast Cancer.

Aerobic glycolysis and the cell cycle are well-established tumor hallmarks. Understanding their relationship could help to unravel the pathogenic mechanisms of breast cancer (BC) and suggest potential new strategies for treatment. Glycolysis-related genes (GRGs) were downloaded from the Reactome database and screened using univariate Cox analysis. The consensus clustering method was employed to identify a glycolytic activity signature (GAS) using the Gene Expression Omnibus (GEO) dataset. A nomogram risk prediction model was constructed using coefficients from univariate Cox analysis. Immune cell infiltration was evaluated using single-sample gene set enrichment analysis (ssGSEA) and the ESTIMATE algorithm. Gene co-expression modules were created using weighted correlation network analysis (WGCNA) to identify hub genes. Gene expression in three BC cell lines was quantified using Quantitative Reverse Transcriptase Polymera (qRT-PCR). Single-cell RNA sequencing (scRNA-seq) data was used to examine the relationship between GAS and hub genes. The sensitivity of different groups to cell cycle-related clinical drugs was also examined. BC with high GAS (HGAS) showed high tumor grade and recurrence rate. HGAS was a prognostic indicator of worse overall survival (OS) in BC patients. HGAS BC showed more abundant immune cells and significantly higher expression of immunomodulators compared to BC with low GAS (LGAS). HGAS BC also showed enhanced cell cycle pathway, with high mRNA and protein expression levels of Cyclin B2 (CCNB2), a key component of the cell cycle pathway. Importantly, scRNA-seq analysis revealed that elevated CCNB2 expression was positively correlated with HGAS in triple-negative BC (TNBC). This was validated in clinical samples from TNBC patients. High expression of CCNB2 was found in three BC cell lines, and was also an indicator of poor prognosis. HGAS BC showed high sensitivity to several cell cycle-related clinical drugs, with 9 of these also showing activity in BC with high CCNB2 expression. HGAS was associated with enhanced cell cycle pathway and immune activity in BC. These results suggest that CCNB2 is a potential key therapeutic target in BC patients.

Phosphoenolpyruvate carboxykinase-2 (PCK2) is a therapeutic target in triple-negative breast cancer.

Metabolic rewiring in malignant transformation is often accompanied by altered expression of metabolic isozymes. Phosphoenolpyruvate carboxykinase-2 (PCK2) catalyzes the rate-limiting step of gluconeogenesis and is the dominant isoform in many cancers including triple-negative breast cancer (TNBC). Our goal was to identify small molecule inhibitors of PCK2 enzyme activity. We assessed the impact of PCK2 down regulation with shRNA on TNBC cell growth in vitro and used AtomNet® deep convolutional neural network software to identify potential small molecule inhibitors of PCK2-based structure. We iteratively tested candidate compounds in an in vitro PCK-2 enzyme assay. The impact of the top hit on metabolic flux and cell viability was also assessed. PCK2 downregulation decreased growth of BT-549 and MDA-MB-231 cells and reduced metabolic flux through pyruvate carboxylase. The first AtomNet® in silico structural screen of 7 million compounds yielded 86 structures that were tested in PCK2 enzyme assay in vitro. The top hit (IC50 = 2.4µM) was used to refine a second round of in silico screen that yielded 82 candidates to be tested in vitro, which resulted in 45 molecules with inhibition > 20%. In the second in vitro screen we also included 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate, previously suggested to be PCK2 inhibitor based on structure, which emerged as the top hit. The specificity of this compound was tested in PCK1 and PCK2 enzymatic assays and showed IC50 of 500nM and 3.5-27nM for PCK1 and PCK2, respectively. 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate is a high affinity PCK2 enzyme inhibitor that also has significant growth inhibitory activity in breast cell lines in vitro and represents a potential therapeutic lead compound.

Synergistic Activation of LEPR and ADRB2 Induced by Leptin Enhances ROS Generation in TNBC Cells.

Leptin interacts not only with leptin receptor (LEPR) but also engages with other receptors. While the pro-oncogenic effects of the adrenergic receptor β2 (ADRB2) are well-established, the role of leptin in activating ADRB2 in triple-negative breast cancer (TNBC) remains unclear. The pro-carcinogenic effects of LEPR were investigated using murine TNBC cell lines, 4T1 and EMT6, and a tumor-bearing mouse model. Expression levels of LEPR, NOX4, and ADRB2 in TNBC cells and tumor tissues were analyzed via Western blot and qPCR. Changes in reactive oxygen species (ROS) levels were assessed using flow cytometry and MitoSox staining, while immunofluorescence double-staining confirmed the co-localization of LEPR and ADRB2. LEPR activation promoted NOX4-derived ROS and mitochondrial ROS production, facilitating TNBC cell proliferation and migration, effects which were mitigated by the LEPR inhibitor Allo-aca. Co-expression of LEPR and ADRB2 was observed on cell membranes, and bioinformatics data revealed a positive correlation between the two receptors. Leptin activated both LEPR and ADRB2, enhancing intracellular ROS generation and promoting tumor progression, which was effectively countered by a specific ADRB2 inhibitor ICI118551. In vivo, leptin injection accelerated tumor growth and lung metastases without affecting appetite, while treatments with Allo-aca or ICI118551 mitigated these effects. This study demonstrates that leptin stimulates the growth and metastasis of TNBC through the activation of both LEPR and ADRB2, resulting in increased ROS production. These findings highlight LEPR and ADRB2 as potential biomarkers and therapeutic targets in TNBC.