Research Progress on Molecular Subtyping and Modern Treatment of Triple-Negative Breast Cancer

Concept of Targeted Drug Conjugate and Its Application in Reversing Drug Resistance

Small-molecule targeted drugs have become the mainstream cancer treatment due to their specific therapy. However, drug resistance inevitably happens to cancer patients. Herein, we propose the "targeted drug conjugate (TDC)" concept to design drugs that enhance antitumor activity, reduce toxicity, and reverse resistance. Upon this idea, compounds Lapa-603 and Lapa-604 were obtained by modifying Pt(II) units with Lapatinib's pharmacophore. Research has found that Lapa-604 can potently inhibit the proliferation of the tested cancer cells and reverse multiple cancer cell resistance by targeting the EGFR protein and causing severe DNA damage. More importantly, Lapa-604 presented higher tumor growth inhibitory efficacy than Lapatinib, Cisplatin, or their physical mixtures in both MDA-MB-231 and BT474 xenograft tumor models. Our research has provided promise for the design and development of novel drugs based on the TDC concept that can effectively overcome drug resistance with stronger antitumor activity and lower toxicity than the corresponding combination therapy.

Ex.50.T aptamer impairs tumor-stroma cross-talk in breast cancer by targeting gremlin-1

The tumor microenvironment profoundly influences tumor complexity, particularly in breast cancer, where cancer-associated fibroblasts play pivotal roles in tumor progression and therapy resistance. Extracellular vesicles are involved in mediating communication within the TME, specifically highlighting their role in promoting the transformation of normal fibroblasts into cancer-associated fibroblasts. Recently, we identified an RNA aptamer, namely ex.50.T, that binds with remarkable affinity to extracellular vesicles shed from triple-negative breast cancer cells. Here, through in vitro assays and computational analyses, we demonstrate that the binding of ex.50.T to extracellular vesicles and parental breast cancer cells is mediated by recognition of gremlin-1 (GREM1), a bone morphogenic protein antagonist implicated in breast cancer aggressiveness and metastasis. Functionally, we uncover the role of ex.50.T as an innovative therapeutic agent in the process of tumor microenvironment re-modeling, impeding GREM1 signaling, blocking triple-negative breast cancer extracellular vesicles internalization in recipient cells, and counteracting the transformation of normal fibroblasts into cancer-associated fibroblasts. Altogether, our findings highlight ex.50.T as a novel therapeutical avenue for breast cancer and potentially other GREM1-dependent malignancies, offering insights into disrupting TME dynamics and enhancing cancer treatment strategies.

Divide and Conquer-Targeted Therapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive and malignant type of breast cancer with limited treatment options and poor prognosis. One of the most significant impediments in TNBC treatment is the high heterogeneity of this disease, as highlighted by the detection of several molecular subtypes of TNBC. Each subtype is driven by distinct mutations and pathway aberrations, giving rise to specific molecular characteristics closely connected to clinical behavior, outcomes, and drug sensitivity. This review summarizes the knowledge regarding TNBC molecular subtypes and how it can be harnessed to devise tailored treatment strategies instead of blindly using targeted drugs. We provide an overview of novel targeted agents and key insights about new treatment modalities with an emphasis on the androgen receptor signaling pathway, cancer stem cell-associated pathways, phosphatidylinositol 3-kinase (PI3K)/AKT pathway, growth factor signaling, and immunotherapy.

Naphthoquinone-derived ZSW-4B induces apoptosis in triple-negative breast cancer via AMPK signalling activation

Triple-negative breast cancer (TNBC) is the most malignant molecular subtype of breast cancer and is characterized by aggressiveness, high mortality, significant heterogeneity, and poor prognosis. AMPK plays a critical role in maintaining the cellular energy balance, and its inactivation is associated with malignant breast cancer. Here, we identified the pharmacological mechanism of the 1,4-naphthoquinone derivative ZSW-4B. MTT, colony formation, and nude mouse xenograft tumour models demonstrated that ZSW-4B selectively inhibits the proliferation of TNBC cells both in vitro and in vivo. Flow cytometry and Western blot analysis revealed that ZSW-4B induces apoptosis in TNBC cells. Phosphoproteomic analysis revealed activation of the AMPK signalling pathway by ZSW-4B. Additionally, the application of the CRISPR-Cas9 system to genetically knockout AMPK in TNBC cell lines was demonstrated to reverse the antitumour effects elicited by ZSW-4B both in vitro and in vivo. In summary, ZSW-4B inhibits TNBC by inducing cellular apoptosis through the activation of AMPK.

Energy and endoplasmic reticulum stress induction by gold(III) dithiocarbamate and 2-deoxyglucose synergistically trigger cell death in breast cancer

The elusiveness of triple-negative breast cancer from targeted therapy has redirected focus towards exploiting the metabolic shortcomings of these highly metastatic subtypes of breast cancer. Cueing from the metabolic heterogeneity of TNBC and the exposition of the dual dependence of some TNBCs on OXPHOS and glycolysis for ATP, we herein report the efficacy of cotreatment of TNBCs with an OXPHOS inhibitor, 2a and 2DG, a potent glycolysis inhibitor. 2a-2DG cotreatment inhibited TNBC cell proliferation with IC50 of ∼5 to 36 times lower than that of 2a alone and over 5000 times lower than IC50 of 2DG alone. 2a-2DG cotreatment suppressed mitochondrial ATP production and significantly induced AMPK activation. Mechanistic studies revealed the distinct yet synergistic contributions of 2a and 2DG to the antiproliferative effect of the cotreatment. While 2a induced apoptotic cell death, 2DG sensitized TNBCs to the antiproliferative effects of 2a via endoplasmic reticulum stress induction. Strikingly, the combination of 2a-2DG ablated SUM159 tumors in an orthotopic xenograft mouse model. This study highlights the synergistic effect of a gold-based complex with 2DG and the potential benefit of multi-metabolic pathways targeting as an effective therapeutic strategy against TNBCs.

Decoding Cancer through Silencing the Mitochondrial Gatekeeper VDAC1

Mitochondria serve as central hubs for regulating numerous cellular processes that include metabolism, apoptosis, cell cycle progression, proliferation, differentiation, epigenetics, immune signaling, and aging. The voltage-dependent anion channel 1 (VDAC1) functions as a crucial mitochondrial gatekeeper, controlling the flow of ions, such as Ca2+, nucleotides, and metabolites across the outer mitochondrial membrane, and is also integral to mitochondria-mediated apoptosis. VDAC1 functions in regulating ATP production, Ca2+ homeostasis, and apoptosis, which are essential for maintaining mitochondrial function and overall cellular health. Most cancer cells undergo metabolic reprogramming, often referred to as the "Warburg effect", supplying tumors with energy and precursors for the biosynthesis of nucleic acids, phospholipids, fatty acids, cholesterol, and porphyrins. Given its multifunctional nature and overexpression in many cancers, VDAC1 presents an attractive target for therapeutic intervention. Our research has demonstrated that silencing VDAC1 expression using specific siRNA in various tumor types leads to a metabolic rewiring of the malignant cancer phenotype. This results in a reversal of oncogenic properties that include reduced tumor growth, invasiveness, stemness, epithelial-mesenchymal transition. Additionally, VDAC1 depletion alters the tumor microenvironment by reducing angiogenesis and modifying the expression of extracellular matrix- and structure-related genes, such as collagens and glycoproteins. Furthermore, VDAC1 depletion affects several epigenetic-related enzymes and substrates, including the acetylation-related enzymes SIRT1, SIRT6, and HDAC2, which in turn modify the acetylation and methylation profiles of histone 3 and histone 4. These epigenetic changes can explain the altered expression levels of approximately 4000 genes that are associated with reversing cancer cells oncogenic properties. Given VDAC1's critical role in regulating metabolic and energy processes, targeting it offers a promising strategy for anti-cancer therapy. We also highlight the role of VDAC1 expression in various disease pathologies, including cardiovascular, neurodegenerative, and viral and bacterial infections, as explored through siRNA targeting VDAC1. Thus, this review underscores the potential of targeting VDAC1 as a strategy for addressing high-energy-demand cancers. By thoroughly understanding VDAC1's diverse roles in metabolism, energy regulation, mitochondrial functions, and other cellular processes, silencing VDAC1 emerges as a novel and strategic approach to combat cancer.

Comparison of the effectiveness of neoadjuvant chemotherapy and adjuvant chemotherapy for improving prognosis in triple-negative breast cancer patients

OBJECTIVE

To compare the effectiveness of surgery combined with neoadjuvant chemotherapy and radiotherapy (SNCR) versus surgery combined with adjuvant chemotherapy and radiotherapy (SACR) in improving the prognosis of triple-negative breast cancer (TNBC) patients.

METHODS

Clinical data from 112 TNBC patients treated between January 2014 and February 2019 were retrospectively collected. Data included clinical characteristics and 5-year disease-free survival (DFS). Kaplan-Meier (K-M) survival curves were used to analyze the associations of various factors with DFS. Lasso-Cox regression was used to screen significant variables identified by K-M survival analysis. Multivariate Cox regression was used to determine independent prognostic factors affecting DFS.

RESULTS

K-M survival analysis showed that treatment regimen (P=0.012), TNM (tumor, node, metastasis) staging (P=0.049), N staging (P=0.015), P53 (P=0.015), KI-67 (P=0.002), neutrophil-to-lymphocyte ratio (NLR) (P<0.001), platelet-to-lymphocyte ratio (PLR) (P<0.001), and cancer antigen 153 (CA153) (P<0.001) were associated with DFS in TNBC patients. Lasso-Cox regression analysis identified treatment regimen, TNM stage, P53, KI-67, NLR, PLR, and CA153 as features related to DFS when λ=0.053741 (1se). Multivariate Cox regression analysis revealed that treatment regimen (P<0.001, 95% CI: 2.309-14.396, HR=5.765), P53 (P=0.010, 95% CI: 1.315-7.864, HR=3.216), and NLR (P=0.001, 95% CI: 2.098-14.553, HR=5.525) were independent prognostic factors affecting DFS. A nomogram model was constructed, and time-dependent receiver operating characteristic (ROC) curve analysis showed that the model's areas under the curve (AUC) for predicting 1-, 3-, and 5-year DFS were 0.928, 0.816, and 0.665, respectively.

CONCLUSION

The SNCR regimen significantly improves DFS in patients with stage IIb to IIIa TNBC compared to the traditional SACR regimen.

Multifunctional calcium-based nanocarriers for synergistic treatment of triple-negative breast cancer

Targeted breast cancer therapies hold the potential to improve the efficiency of drug delivery to the pathology site without impacting the viability and function of healthy cells. Herein, we developed multifunctional nanocarriers that target simultaneously several downstream signaling processes in triple negative breast cancer cells. The system comprises pH sensitive CaCO3 nanoparticles (NPs) as carriers of the anticancer drug doxorubicin (DOX). The NPs were coated in a layer-by-layer (LbL) fashion using poly-l-lysine and hyaluronic acid to target receptors overexpressed in breast cancer (e.g. CD44, RHAMM). Spheroids of the triple-negative Hs578T cell line were used as a 3D model to assess the therapeutic potential of this system. Our results showed that the NPs act via a synergistic mechanism that combines Ca2+ overload causing cell calcification and DNA damage by DOX. The LbL coating was crucial for the protection of the healthy cells, i.e. it provides NPs with targeting capacity. The overall data suggests that the LbL-coated NPs loaded with DOX hold great potential for the treatment of breast cancer.

Research and experimental verification on the mechanisms of cellular senescence in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with high heterogeneity, poor prognosis, and a low 10-year survival rate of less than 50%. Although cellular senescence displays extensive effects on cancer, the comprehensions of cellular senescence-related characteristics in TNBC patients remains obscure.

Method

Single-cell RNA sequencing (scRNA-seq) data were analyzed by Seurat package. Scores for cellular senescence-related pathways were computed by single-sample gene set enrichment analysis (ssGSEA). Subsequently, unsupervised consensus clustering was performed for molecular cluster identification. Immune scores of patients in The Cancer Genome Atlas (TCGA) dataset and associated immune cell scores were calculated using Estimation of STromal and Immune cells in MAlignantTumours using Expression data (ESTIMATE) and Microenvironment Cell Populations-counter (MCP-counter), Tumor Immune Estimation Resource (TIMER) and Estimating the Proportion of Immune and Cancer cells (EPIC) methods, respectively. Immunotherapy scores were assessed using TIDE. Furthermore, feature genes were identified by univariate Cox and Least Absolute Shrinkage and Selection Operator (LASSO) regression analyses; these were used to construct a risk model. Additionally, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and transwell assay were conducted for in vitro validation of hub genes.

Result

TNBC was classified into three subtypes based on cellular senescence-related pathways as clusters 1, 2, and 3. Specifically, cluster 1 showed the best prognosis, followed by cluster 2 and cluster 3. The levels of gene expression in cluster 2 were the lowest, whereas these were the highest in cluster 3. Moreover, clusters 1 and 3 showed a high degree of immune infiltration. TIDE scores were higher for cluster 3, suggesting that immune escape was more likely in patients with the cluster 3 subtype who were less likely to benefit from immunotherapy. Next, the TNBC risk model was constructed and validated. RT-qPCR revealed that prognostic risk genes (MMP28, ACP5 and KRT6A) were up-regulated while protective genes (CT83) were down-regulated in TNBC cell lines, validating the results of the bioinformatics analysis. Meanwhile, cellular experiments revealed that ACP5 could promote the migration and invasion abilities in two TNBC cell lines. Finally, we evaluated the validity of prognostic models for assessing TME characteristics and TNBC chemotherapy response.

Conclusion

In conclusion, these findings help to assess the efficacy of targeted therapies in patients with different molecular subtypes, have practical applications for subtype-specific treatment of TNBC patients, and provide information on prognostic factors, as well as guidance for the revelation of the molecular mechanisms by which senescence-associated genes influence TNBC progression.