INTRODUCTION: Trastuzumab deruxtecan (T-DXd) has revolutionised treatment for metastatic breast cancer (MBC). While effective, its high cost and toxicities, such as fatigue and nausea, pose challenges. METHOD: Medical records from the Joint Breast Cancer Registry in Singapore were used to study MBC patients treated with T-DXd (February 2021-June 2024). This study was conducted to address whether reducing dose intensity and density may have an adverse effect on treatment outcomes. RESULTS: Eighty-seven MBC patients were treated with T-DXd, with a median age of 59 years. At the time of data cutoff, 32.1% of patients were still receiving T-DXd. Over half (54%) of the patients received treatment with an initial relative dose intensity (RDI) of <;85%. Overall median real-world progression-free survival (rwPFS) was 8.1 months. rwPFS was similar between RDI groups (<85%: 8.7 months, <85%: 8.1 months, P=0.62). However, human epidermal growth receptor 2 (HER2)-positive patients showed significantly better rwPFS outcomes compared to HER2-low patients (8.8 versus 2.5 months, P<0.001). Only 16% with central nervous system (CNS) involvement had CNS progressive disease on treatment. No significant progression-free survival (PFS) differences were found between patients with or without CNS disease, regardless of RDI groups. Five patients (5.7%) developed interstitial lung disease (ILD), with 3 (3.4%) having grade 3 events. Two required high-dose steroids and none were rechallenged after ILD. There were no fatalities. CONCLUSION Our study demonstrated that reduced dose intensity and density had no significant impact on rwPFS or treatment-related toxicities. Furthermore, only 5.7% of patients developed ILD. T-Dxd provided good control of CNS disease, with 82% of patients achieving CNS disease control.
Humans ; Female ; Breast Neoplasms/mortality* ; Middle Aged ; Trastuzumab/adverse effects* ; Aged ; Adult ; Singapore/epidemiology* ; Antineoplastic Agents, Immunological/adverse effects* ; Camptothecin/adverse effects* ; Immunoconjugates/adverse effects* ; Retrospective Studies ; Progression-Free Survival ; Receptor, ErbB-2/metabolism* ; Neoplasm Metastasis ; Dose-Response Relationship, Drug ; Treatment Outcome ; Registries

BACKGROUND: In the interim analysis of MONARCH plus, adding abemaciclib to endocrine therapy (ET) improved progression-free survival (PFS) and objective response rate (ORR) in predominantly Chinese postmenopausal women with HR+/HER2- advanced breast cancer (ABC). This study presents the final pre-planned PFS analysis. METHODS: In the phase III MONARCH plus study, postmenopausal women in China, India, Brazil, and South Africa with HR+/HER2- ABC without prior systemic therapy in an advanced setting (cohort A) or progression on prior ET (cohort B) were randomized (2:1) to abemaciclib (150 mg twice daily [BID]) or placebo plus: anastrozole (1.0 mg/day) or letrozole (2.5 mg/day) (cohort A) or fulvestrant (500 mg on days 1 and 15 of cycle 1 and then on day 1 of each subsequent cycle) (cohort B). The primary endpoint was PFS of cohort A. Secondary endpoints included cohort B PFS (key secondary endpoint), ORR, overall survival (OS), safety, and health-related quality of life (HRQoL). RESULTS: In cohort A (abemaciclib: n  = 207; placebo: n  = 99), abemaciclib plus a non-steroidal aromatase inhibitor improved median PFS vs . placebo (28.27 months vs . 14.73 months, hazard ratio [HR]: 0.476; 95% confidence interval [95% CI]: 0.348-0.649). In cohort B (abemaciclib: n  = 104; placebo: n  = 53), abemaciclib plus fulvestrant improved median PFS vs . placebo (11.41 months vs . 5.59 months, HR: 0.480; 95% CI: 0.322-0.715). Abemaciclib numerically improved ORR. Although immature, a trend toward OS benefit with abemaciclib was observed (cohort A: HR: 0.893, 95% CI: 0.553-1.443; cohort B: HR: 0.512, 95% CI: 0.281-0.931). The most frequent grade ≥3 adverse events in the abemaciclib arms were neutropenia, leukopenia, anemia (both cohorts), and lymphocytopenia (cohort B). Abemaciclib did not cause clinically meaningful changes in patient-reported global health, functioning, or most symptoms vs . placebo. CONCLUSIONS: Abemaciclib plus ET led to improvements in PFS and ORR, a manageable safety profile, and sustained HRQoL, providing clinical benefit without a high toxicity burden or reduced quality of life. TRIAL REGISTRATION ClinicalTrials.gov (NCT02763566).
Humans ; Female ; Fulvestrant/therapeutic use* ; Breast Neoplasms/metabolism* ; Aminopyridines/therapeutic use* ; Benzimidazoles/therapeutic use* ; Middle Aged ; Aromatase Inhibitors/therapeutic use* ; Aged ; Receptor, ErbB-2/metabolism* ; Adult ; Letrozole/therapeutic use* ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; Anastrozole/therapeutic use*

The inhibition of cyclin-dependent kinases (CDKs) is considered a promising strategy for cancer treatment due to their role in cell cycle regulation. However, CDK inhibitors with no selectivity among CDK families have not been approved. A CDK inhibitor with high selectivity for CDK4/6 exhibited significant treatment effects on breast cancer and has become a heavy bomb on the market. Subsequently, resistance gradually decreased the efficacy of selective CDK4/6 inhibitors in breast cancer treatment. In this review, we first introduce the development of selective CDK4/6 inhibitors and then explain the role of CDK2 activation in inducing resistance to CDK4/6 inhibitors. Moreover, we focused on the development of CDK2/4/6 inhibitors and selective CDK2 inhibitors, which will aid in the discovery of novel CDK inhibitors targeting the cell cycle in the future.
Humans ; Cell Cycle/drug effects* ; Protein Kinase Inhibitors/chemistry* ; Cyclin-Dependent Kinases/metabolism* ; Neoplasms/genetics* ; Antineoplastic Agents/pharmacology* ; Animals ; Breast Neoplasms/enzymology* ; Cyclin-Dependent Kinase 4/metabolism*

Triple-negative breast cancer (TNBC) represents an aggressive breast cancer subtype with poor prognosis and limited targeted treatment options. This investigation examined the anti-cancer potential of Caerulomycin A (Cae A), a natural compound derived from marine actinomycetes, against TNBC. Cae A demonstrated selective inhibition of viability and proliferation in TNBC cell lines, including 4T1, MDA-MB-231, and MDA-MB-468, through apoptosis induction. Mechanistic analyses revealed that the compound induced sustained endoplasmic reticulum (ER) stress and subsequent upregulation of C/EBP homologous protein (CHOP) expression, resulting in mitochondrial damage-mediated apoptosis. Inhibition of ER stress or CHOP expression knockdown reversed mitochondrial damage and apoptosis, highlighting the essential role of ER stress and CHOP in Cae A's anti-tumor mechanism. Both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) decreased in TNBC cells following Cae A treatment, indicating reduced mitochondrial respiratory and glycolytic capacities. This diminished energy metabolism potentially triggers ER stress and subsequent apoptosis. Furthermore, Cae A exhibited significant anti-tumor effects in the 4T1 tumor model in vivo without apparent toxicity. The compound also effectively inhibited human TNBC organoid growth. These results indicate that Cae A may serve as a potential therapeutic agent for TNBC, with its efficacy likely mediated through the disruption of glucose metabolism and the induction of ER stress-associated apoptosis.
Humans ; Endoplasmic Reticulum Stress/drug effects* ; Triple Negative Breast Neoplasms/genetics* ; Apoptosis/drug effects* ; Cell Line, Tumor ; Female ; Animals ; Glucose/metabolism* ; Mice ; Cell Proliferation/drug effects* ; Transcription Factor CHOP/genetics* ; Antineoplastic Agents/pharmacology* ; Mitochondria/metabolism* ; Mice, Inbred BALB C

BACKGROUND: To date, results on relationship between CYP3A4 gene polymorphism were limited and inconclusive, and no study focused on the influence of CYP3A4 gene-obesity interaction on breast cancer risk, especially in Chinese women. The purpose of this study was to evaluate the impact of four single nucleotide polymorphisms (SNPs) of CYP3A4 gene, the SNP-SNP and gene-environment interactions on the susceptibility to breast cancer in Chinese women. METHODS: Logistic regression was used to explore the relationship between four SNPs of CYP3A4 gene and the risk of breast cancer. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best SNP-SNP and gene-abdominal obesity interaction combinations among four SNPs and abdominal obesity. Haplotype examination among 4 SNPs was conducted using the SHEsis web-based platform. RESULTS: Logistic regression analysis showed that carriers of rs2242480- T allele have significantly higher breast cancer risk, than those with rs2242480- CC genotype, adjusted OR (95%CI) was 1.68 (1.23-2.16) and 2.03 (1.53-2.58) for participants with CT genotype and TT genotype under additive model. We did not find any notable interactions between the four SNPs within the CYP3A4 gene. GMDR model found a significant association in a two-locus model involving rs2242480 and obesity, with a p-value of 0.018. Stratified analysis found that breast cancer risk was the highest in obese participants with rs2242480- CT or TT genotype, compared to those non-obese participants with rs2242480- CC genotype, OR (95%CI) was 3.02 (1.83-4.25). We found that all haplotype combinations were not correlated with breast cancer risk. CONCLUSIONS We found that the T allele of rs2242480 within the CYP3A4 gene and interaction between rs2242480 and obesity were associated with an increased risk of breast cancer. However, the results of this study were only applicable to the Han ethnic group and cannot be generalized to other ethnic groups in China, and more SNPs of CYP3A4 gene should been enrolled in the analysis in the future, to verify the results obtained in this study.
Adult ; Aged ; Female ; Humans ; Middle Aged ; Breast Neoplasms/etiology* ; China/epidemiology* ; Cytochrome P-450 CYP3A/metabolism* ; Gene-Environment Interaction ; Genetic Predisposition to Disease ; Haplotypes ; Obesity/epidemiology* ; Polymorphism, Single Nucleotide ; Risk Factors ; East Asian People

OBJECTIVE: To entrap carvacrol (CAR) in bovine serum albumin nanoparticles (BSANPs) to form CAR-loaded BSANPs (CAR@BSANPs) and to explore the anti-cancer effects in breast adenocarcinoma cells (MCF-7 cells) treated with CAR and CAR@BSANPs. METHODS: A desolvation method was used to synthesize BSANPs and CAR@BSANPs. The BSANPs and CAR@BSANPs were characterized by several physicochemical methods, including visual observation, high-resolution field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and high-performance liquid chromatography. MCF-7 cells were used and analyzed after 24 h of exposure to CAR and CAR@BSANPs at half-maximal inhibitory concentration. The anti-proliferative, apoptotic, reactive oxygen species (ROS), and nitric oxide (NO) scavenging activity as well as gene expression analysis were investigated by the cell viability assay, phase-contrast microscopy, 2',7'-dichlorofluorescein-diacetate assay, Griess-Illosvoy colorimetric assay, and quantitative real-time polymerase chain reaction, respectively. RESULTS: CAR and CAR@BSANPs showed anti-proliferative, apoptotic, ROS generation, and NO scavenging effects on MCF-7 cells. Expression profile of B-cell lymphoma 2-like 11 (BCL2L11), vascular endothelial growth factor A (VEGFA), hypoxia inducible factor factor-1α (HIF1A), BCL2L11/apoptosis regulator (BAX), and BCL2L11/Bcl2 homologous antagonist/killer 1 (BAK1) ratios revealed downregulated genes; and BAX, BAK1, and CASP8 were upregulated by CAR and CAR@BSANPs treatment. In vitro anticancer assays of the CAR and CAR@BSANPs showed that CAR@BSANPs demonstrated higher therapeutic efficacy in the MCF-7 cells than CAR. CONCLUSIONS CAR and CAR@BSANPs affect gene expression and may subsequently reduce the growth and proliferation of the MCF-7 cells. Molecular targeting of regulatory genes of the MCF-7 cells with CAR and CAR@BSANPs may be an effective therapeutic strategy against breast cancer.
Humans ; Cymenes ; Nanoparticles/ultrastructure* ; MCF-7 Cells ; Breast Neoplasms/genetics* ; Apoptosis/drug effects* ; Serum Albumin, Bovine/chemistry* ; Monoterpenes/therapeutic use* ; Adenocarcinoma/genetics* ; Cell Proliferation/drug effects* ; Reactive Oxygen Species/metabolism* ; Female ; Cell Survival/drug effects* ; Animals ; Gene Expression Regulation, Neoplastic/drug effects* ; Nitric Oxide/metabolism* ; Cattle

Breast cancer is one of the most common and fatal malignancies among women worldwide, and its treatment efficacy is often limited by drug resistance and the presence of undruggable targets. Traditional small-molecule drugs have difficulty effectively modulating certain critical targets such as transcription factors and non-coding RNAs, necessitating new therapeutic strategies. Proteolysis-targeting chimeras (PROTACs) function by recruiting pathogenic proteins to the cellular ubiquitin-proteasome system, thereby inducing their specific degradation. In contrast, ribonuclease-targeting chimeras (RIBOTACs) utilize small-molecule ligands but bind to RNA and direct endogenous RNases to selectively degrade pathogenic RNA molecules. By employing a "degradation rather than inhibition" mechanism, targeting chimera technology broadens the druggable landscape and offers a novel precision therapeutic strategy for breast cancer, particularly for refractory and drug-resistant cases. This approach not only overcomes the limitations of traditional drugs, such as the absence of suitable binding sites or poor selectivity, but also reduces required dosages and potential adverse effects. Recent studies have preliminarily demonstrated the therapeutic potential of PROTACs and RIBOTACs in breast cancer, encompassing target design, mechanistic investigation, and preclinical as well as early clinical applications. Research into these technologies reveals their ability to tackle previously undruggable targets, thereby providing theoretical support for the development of safer and more effective precision therapies for breast cancer. In the future, with advances in drug delivery systems and clinical trials, PROTACs and RIBOTACs are expected to be used synergistically with immunotherapy and chemotherapy, offering breast cancer patients more promising comprehensive treatment options and potentially driving oncology toward broader intervention of undruggable targets.
Humans ; Breast Neoplasms/drug therapy* ; Female ; Proteolysis ; Ribonucleases/metabolism* ; Molecular Targeted Therapy/methods* ; Antineoplastic Agents/therapeutic use*

OBJECTIVES: To explore the mechanism by which Pulsatilla saponin D (PSD) inhibits invasion and metastasis of triple-negative breast cancer (TNBC). METHODS: The public databases were used to identify the potential targets of PSD and the invasion and metastasis targets of TNBC to obtain the intersection targets between PSD and TNBC. The "PSD-target-disease" interaction network was constructed and protein-protein interaction (PPI) analysis was performed to obtain the core targets, which were analyzed for KEGG pathway and GO functional enrichment. Molecular docking study of the core targets and PSD was performed, and the therapeutic effect and mechanism of PSD were verified using Transwell assay and Western blotting in cultured TNBC cells. RESULTS: Network pharmacology analysis identified a total of 285 potential PSD targets and 26 drug-disease intersection core targets. GO analysis yielded 175 entries related to the binding of biomolecules (protein, DNA and RNA), enzyme activities, and regulation of gene transcription. KEGG analysis yielded 46 entries involving pathways in cancer, chemical carcinogenesis-receptor activation, microRNAs in cancer, chemical carcinogenesis-reactive oxygen species, PD-L1 expression and PD-1 checkpoint pathway in cancer. Molecular docking showed high binding affinities of PSD to MTOR, HDAC2, ABL1, CDK1, TLR4, TERT, PIK3R1, NFE2L2 and PTPN1. In cultured TNBC cells, treatment with PSD significantly inhibited cell invasion and migration and lowered the expressions of MMP2, MMP9, N-cadherin and the core proteins p-mTOR, ABL1, TERT, PTPN1, HDAC2, PIK3R1, CDK1, TLR4 as well as NFE2L2 expressionin the cell nuclei. CONCLUSIONS The inhibitory effects of PSD on TNBC invasion and metastasis are mediated by multiple targets and pathways.
Humans ; Triple Negative Breast Neoplasms/metabolism* ; Saponins/pharmacology* ; Pulsatilla/chemistry* ; Female ; Molecular Docking Simulation ; Cell Line, Tumor ; Neoplasm Invasiveness ; Protein Interaction Maps ; Neoplasm Metastasis ; Signal Transduction/drug effects* ; Cell Movement/drug effects*

OBJECTIVES: To investigate the effects of dihydroartemisinin (DHA) combined with doxorubicin (DOX) on proliferation and apoptosis of triple-negative breast cancer cells and explore the underlying molecular mechanism. METHODS: MDA-MB-231 cells were treated with 50, 100 or 150 μmol/L DHA, 0.5 μmol/L DOX, or with 50 μmol/L DHA combined with 0.5 μmol/L DOX. The changes in proliferation and survival of the treated cells were examined with MTT assay and colony-forming assay, and cell apoptosis was analyzed with flow cytometry. Western blotting was performed to detect the changes in protein expression levels of PCNA, cleaved PARP, Bcl-2, Bax, STAT3, p-STAT3, HIF-1α and survivin. RESULTS: The IC₅₀ of DHA was 131.37±29.87 μmol/L in MDA-MB-231 cells. The cells with the combined treatment with DHA and DOX showed significant suppression of cell proliferation. Treatment with DHA alone induced apoptosis of MDA-MB-231 cells in a dose-dependent manner, but the combined treatment produced a much stronger apoptosis-inducing effect than both DHA and DOX alone. DHA at 150 μmol/L significantly inhibited clone formation of MDA-MB-231 cells, markedly reduced cellular expression levels of PCNA, p-STAT3, HIF-1α and survivin proteins, and obviously increased the expression level of cleaved PARP protein and the Bax/Bcl-2 ratio, and the combined treatment further reduced the expression level of p-STAT3 protein and increased the Bax/Bcl-2 ratio. CONCLUSIONS DHA combined with DOX produces significantly enhanced effects for inhibiting cell proliferation and inducing apoptosis in MDA-MB-231 cells possibly as result of DHA-mediated negative regulation of the STAT3/HIF-1α pathway.
Humans ; STAT3 Transcription Factor/metabolism* ; Apoptosis/drug effects* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Doxorubicin/pharmacology* ; Triple Negative Breast Neoplasms/metabolism* ; Cell Line, Tumor ; Artemisinins/pharmacology* ; Female ; Cell Proliferation/drug effects* ; Signal Transduction/drug effects* ; Survivin

OBJECTIVES: To investigate the effect of downregulation of medium-chain acyl-coenzyme A dehydrogenase (ACADM) on invasion and migration of estrogen receptor-positive breast cancer cells and the underlying mechanism. METHODS: The Kaplan-Meier Plotter database was used to analyze the ACADM expression levels in breast cancer and normal tissues and their association with patient prognosis. Human breast cancer MCF-7 and T47D cell lines with lentivirus-mediated ACADM knockdown were established, and their in situ tumor formation and metastasis after tail vein injection were evaluated in nude mice. The MCF-7 and T47D cells with ACADM knockdown and their unmodified parental cells were examined with oil-red O staining assay, ROS assay, mitochondrial respiratory chain function assay before and after treatments with ROS scavenger, Elamipretide (a cardiolipin oxidation inhibitor) or SC79 (an AKT activator), and the changes in migration and invasion abilities of the treated cells were analyzed with Transwell invasion assay and Boyden chamber assay. Western blotting was used to detect protein expression levels of related signaling pathways in the treated cells. RESULTS: ACADM overexpression was associated with a significantly shorter overall survival of breast cancer patients. In MCF-7 and T47D cells, ACADM knockdown resulted in downregulation of N calnexin, vimentin, p-P13K and p-AKT proteins, increased levels of free fatty acids and reactive oxygen species, lowered activities of mitochondrial respiratory chain complex III and V, and reduced mitochondrial inner phospholipids. ACADM knockdown significantly decreased the invasive capacity of the cells, which were obviously reversed by treatment with ROS scavenger, Elamipretide, and SC79. CONCLUSIONS Down-regulation of ACADM inhibits migration and invasion ability of estrogen receptor-positive breast cancer cells by lowering lipotoxicity and impairing mitochondrial function through the ROS/PI3K/AKT pathway.
Humans ; Breast Neoplasms/metabolism* ; Female ; Mice, Nude ; Down-Regulation ; Neoplasm Invasiveness ; Animals ; Mice ; Receptors, Estrogen/metabolism* ; MCF-7 Cells ; Cell Movement ; Cell Line, Tumor ; Reactive Oxygen Species/metabolism* ; Acyl-CoA Dehydrogenase/genetics* ; Signal Transduction ; Neoplasm Metastasis ; Proto-Oncogene Proteins c-akt/metabolism*