Relationship between metabolic reprogramming and drug resistance in breast cancer

Immunotherapy in breast cancer: current landscape and emerging trends

Breast cancer remains one of the most prevalent malignancies worldwide, underscoring an urgent need for innovative therapeutic strategies. Immunotherapy has emerged as a transformative frontier in this context. In triple-negative breast cancer (TNBC), the combination of immunotherapy based on PD-1/PD-L1 immune checkpoint inhibitors (ICIs) with chemotherapy has proven efficacious in both early and advanced clinical trials. These encouraging results have led to the approval of ICIs for TNBC, opening up new therapeutic avenues for challenging-to-treat patient populations. Furthermore, a multitude of ongoing trials are actively investigating the efficacy of immunotherapy-based combinations, including ICIs in conjunction with chemotherapy, targeted therapy and radiation therapy, as well as other novel strategies such as bispecific antibodies, CAR-T cells and cancer vaccines across all breast cancer subtypes, including HR-positive/HER2-negative and HER2-positive disease. This review provides a comprehensive overview of current immunotherapeutic approaches in breast cancer, highlighting pivotal findings from recent clinical trials and the potential impact of these advancements on patient outcomes.

Targeting the Hippo Pathway in Breast Cancer: A Proteomic Analysis of Yes-Associated Protein Inhibition

The dysregulation of the Hippo signaling pathway leads to the aberrant activation of oncogenic YAP and TAZ, driving tumor progression. In breast cancer, this disruption promotes proliferation and metastasis. This study investigates the effects of CA3, a selective YAP inhibitor, on the proteome of triple-negative breast cancer MDA-MB-231 and luminal-A-like MCF7 cells. Proteomic changes were analyzed via nano-LC-MS/MS, while cytotoxicity, apoptosis, and autophagy were assessed through WST-1 assays, flow cytometry, and Western blot analyses. Bioinformatics tools were employed to identify enriched pathways. MDA-MB-231 cells exhibited an increased expression of DNA repair proteins (p < 0.05), indicating a compensatory response to maintain genomic stability. In contrast, MCF7 cells showed a downregulation of DNA repair factors (p < 0.005). Additionally, metabolic reprogramming was apparent in MCF7 cells (p < 0.001). Apoptosis assays revealed a rise in cell death, while cell cycle analysis indicated pronounced G1-phase arrest in MDA-MB-231 cells (p < 0.01). Moreover, autophagic suppression was particularly evident in MCF7 cells. This study, for the first time, provides evidence that breast cancer subtypes exhibit distinct dependencies on YAP-driven pathways, revealing potential therapeutic vulnerabilities. Targeting Hippo signaling alongside DNA repair in triple-negative breast cancer or combining YAP inhibition with metabolic blockade in luminal breast cancer holds significant potential to enhance treatment efficacy.

The Adaptation of MCF-7 Breast Cancer Spheroids to the Chemotherapeutic Doxorubicin: The Dynamic Role of Phase I Drug Metabolizing Enzymes

Background/Objectives: Drug resistance (DR) is a major challenge in cancer therapy, contributing to approximately 90% of cancer-related deaths. While alterations in drug metabolism are known to be key drivers of DR, their role-particularly in the early stages of acquired chemoresistance-remains understudied. Phase I drug-metabolizing enzymes (DMEs), especially cytochrome P450s (CYPs), significantly influence the metabolic fate of chemotherapeutic agents, directly affecting drug response. This study aimed to investigate the role of Phase I DMEs in the early metabolic adaptation of breast cancer (BC) MCF-7 cells to doxorubicin (DOX). Methods: Four types of spheroids were generated from MCF-7 cells that were either DOX-sensitive (DOXS) or adapted to low concentrations of the chemotherapeutic agent (DOXA 25, 35, and 45 nM). The expression levels of 92 Phase I DMEs and the activities of specific CYP isoforms were assessed in both DOXS and DOXA spheroids. Results: A total of twenty-four DMEs, including fifteen CYPs and nine oxidoreductases, were found to be differentially expressed in DOXA spheroids. Pathway analysis identified key roles for the differentially expressed DMEs in physiologically relevant pathways, including the metabolism of drugs, arachidonic acid, retinoic acid, and vitamin D. Conclusions: The deconvolution of these pathways highlights a highly dynamic process driving early-stage DOX resistance, with a prominent role of CYP3A-dependent metabolism in DOX adaptation. Our findings provide valuable insights into the underlying molecular mechanisms driving the early adaptation of MCF-7 cells to DOX exposure.

Adaptive Proteomic Changes in Protein Metabolism and Mitochondrial Alterations Associated with Resistance to Trastuzumab and Pertuzumab Therapy in HER2-Positive Breast Cancer

HER2 (human epidermal growth factor receptor 2) is overexpressed in approximately 15-20% of breast cancers, leading to aggressive tumour growth and poor prognosis. Anti-HER2 therapies, such as trastuzumab and pertuzumab, have significantly improved the outcomes for patients with HER2-positive breast cancer by blocking HER2 signalling. However, intrinsic and acquired resistance remains a major clinical challenge, limiting the long-term effectiveness of these therapies. Understanding the mechanisms of resistance is essential for developing strategies to overcome it and improve the therapeutic outcomes. We generated multiple HER2-positive breast cancer cell line models resistant to trastuzumab and pertuzumab combination therapy. Using mass spectrometry-based proteomics, we conducted a comprehensive analysis to identify the mechanisms underlying resistance. Proteomic analysis identified 618 differentially expressed proteins, with a core of 83 overexpressed and 118 downregulated proteins. Through a series of advanced bioinformatics analyses, we identified significant protein alterations and signalling pathways potentially responsible for the development of resistance, revealing key alterations in the protein metabolism, mitochondrial function, and signalling pathways, such as MAPK, TNF, and TGFβ. These findings identify mitochondrial activity and detoxification processes as pivotal mechanisms underlying the resistance to anti-HER2 therapy. Additionally, we identified key proteins, including ANXA1, SLC2A1, and PPIG, which contribute to the tumour progression and resistance phenotype. Our study suggests that targeting these pathways and proteins could form the basis of novel therapeutic strategies to overcome resistance in HER2-positive breast cancer.

Real-world clinical multi-omics analyses reveal bifurcation of ER-independent and ER-dependent drug resistance to CDK4/6 inhibitors

To better understand drug resistance mechanisms to CDK4/6 inhibitors and inform precision medicine, we analyze real-world multi-omics data from 400 HR+/HER2- metastatic breast cancer patients treated with CDK4/6 inhibitors plus endocrine therapies, including 200 pre-treatment and 227 post-progression samples. The prevalences of ESR1 and RB1 alterations significantly increase in post-progression samples. Integrative clustering analysis identifies three subgroups harboring different resistance mechanisms: ER driven, ER co-driven and ER independent. The ER independent subgroup, growing from 5% pre-treatment to 21% post-progression, is characterized by down-regulated estrogen signaling and enrichment of resistance markers including TP53 mutations, CCNE1 over-expression and Her2/Basal subtypes. Trajectory inference analyses identify a pseudotime variable strongly correlated with ER independence and disease progression; and revealed bifurcated evolutionary trajectories for ER-independent vs. ER-dependent drug resistance mechanisms. Machine learning models predict therapeutic dependency on ESR1 and CDK4 among ER-dependent tumors and CDK2 dependency among ER-independent tumors, confirmed by experimental validation.

Phase angle as a potential tool to evaluate chronic inflammatory state and predict quality of life deterioration in women with breast cancer and obesity: A narrative review

The interaction between lifestyle--defined more specifically in health care as the personal exposome--and its implications on obesity and breast cancer development highlights the critical role of body composition and inflammation in these patients. There is clear evidence that the personal and internal exposome triggers biochemical, inflammatory, and metabolic reprogramming, which might favor ectopic lipid accumulation within the body, such as muscles. Additionally, the presence of excessive adipose tissue exacerbates these alterations in the internal exposome, resulting in cell damage and modifying body composition. Understanding the nexus between these lifestyle-induced exposome modifications, such as inflammation, and the resultant changes in body composition is crucial to assess the association with breast cancer progression and treatment responses. Various techniques can be used to evaluate body composition; one of those most used currently is bioelectrical impedance analysis. This analysis provides parameters, including phase angle (PhA), by which cellular health and metabolic activity can be assessed. In addition, PhA is a potential indicator of nutritional status and disease prognosis, as it has been linked to survival and quality of life in patients with cancer. Therefore, PhA might be used in daily oncology practice to implement an accurate nutritional intervention, reducing side effects and complications of oncology management, and improving quality of life during treatment and survival, even in patients with breast cancer with obesity or overweight. The aim of this review is to analyze the existing information on the current application of PhA in patients with breast cancer and its potential use as a tool to assess inflammatory response, identify malnutrition, and predict the deterioration of quality of life so that it could be proposed as an early indicator for nutritional interventions in this group of patients.

Mitochondrial signaling pathways and their role in cancer drug resistance

Mitochondria, traditionally known as cellular powerhouses, now emerge as critical signaling centers influencing cancer progression and drug resistance. The review highlights the role that apoptotic signaling, DNA mutations, mitochondrial dynamics and metabolism play in the development of resistance mechanisms and the advancement of cancer. Targeted approaches are discussed, with an emphasis on managing mitophagy, fusion, and fission of the mitochondria to make resistant cancer cells more susceptible to traditional treatments. Additionally, metabolic reprogramming can be used to effectively target metabolic enzymes such GLUT1, HKII, PDK, and PKM2 in order to avoid resistance mechanisms. Although there are potential possibilities for therapy, the complex structure of mitochondria and their subtle role in tumor development hamper clinical translation. Novel targeted medicines are put forth, providing fresh insights on combating drug resistance in cancer. The study also emphasizes the significance of glutamine metabolism, mitochondrial respiratory complexes, and apoptotic pathways as potential targets to improve treatment effectiveness against drug-resistant cancers. Combining complementary and nanoparticle-based techniques to target mitochondria has demonstrated encouraging results in the treatment of cancer, opening doors to reduce resistance and enable individualized treatment plans catered to the unique characteristics of each patient. Suggesting innovative approaches such as drug repositioning and mitochondrial drug delivery to enhance the efficacy of mitochondria-targeting therapies, presenting a pathway for advancements in cancer treatment. This thorough investigation is a major step forward in the treatment of cancer and has the potential to influence clinical practice and enhance patient outcomes.

Spatial Metabolomics Profiling Reveals Curcumin Induces Metabolic Reprogramming in Three-Dimensional Tumor Spheroids

Curcumin is widely recognized for its diverse antitumor properties, ranging from breast cancer to many other types of cancers. However, its role in the tumor microenvironment remains to be elucidated. In this study, we established a 3D tumor spheroids model that can simulate the growth environment of tumor cells and visualized the antitumor metabolic alteration caused by curcumin using mass spectrometry imaging technology. Our results showed that curcumin not only exerts a profound impact on the growth and proliferation of breast cancer cells but in situ multivariate statistical analysis also reveals the significant effect on the overall metabolic profile of tumor spheroids. Meanwhile, our visualization map characterized curcumin metabolic processes of reduction and glucuronidation in tumor spheroids. More importantly, abnormal metabolic pathways related to lipid metabolism and polyamine metabolism were also remodeled at the metabolite and gene levels after curcumin intervention. These insights deepen our comprehension of the regulatory mechanism of curcumin on the tumor metabolic network, furnishing powerful references for antitumor treatment.

Depicting Biomarkers for HER2-Inhibitor Resistance: Implication for Therapy in HER2-Positive Breast Cancer

HER2 (human epidermal growth factor receptor 2) is highly expressed in a variety of cancers, including breast, lung, gastric, and pancreatic cancers. Its amplification is linked to poor clinical outcomes. At the genetic level, HER2 is encoded by the ERBB2 gene (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2), which is frequently mutated or amplified in cancers, thus spurring extensive research into HER2 modulation and inhibition as viable anti-cancer strategies. An impressive body of FDA-approved drugs, including anti-HER2 monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and HER2-tyrosine kinase inhibitors (TKIs), have demonstrated success in enhancing overall survival (OS) and disease progression-free survival (PFS). Yet, drug resistance remains a persistent challenge and raises the risks of metastatic potential and tumor relapse. Research into alternative therapeutic options for HER2+ breast cancer therefore proves critical for adapting to this ever-evolving landscape. This review highlights current HER2-targeted therapies, discusses predictive biomarkers for drug resistance, and introduces promising emergent therapies-especially combination therapies-that are aimed at overcoming drug resistance in the context of HER2+ breast cancer.

Mitochondrial inhibitors: a new horizon in breast cancer therapy

Breast cancer, due to resistance to standard therapies such as endocrine therapy, anti-HER2 therapy and chemotherapy, continues to pose a major health challenge. A growing body of research emphasizes the heterogeneity and plasticity of metabolism in breast cancer. Because differences in subtypes exhibit a bias toward metabolic pathways, targeting mitochondrial inhibitors shows great potential as stand-alone or adjuvant cancer therapies. Multiple therapeutic candidates are currently in various stages of preclinical studies and clinical openings. However, specific inhibitors have been shown to face multiple challenges (e.g., single metabolic therapies, mitochondrial structure and enzymes, etc.), and combining with standard therapies or targeting multiple metabolic pathways may be necessary. In this paper, we review the critical role of mitochondrial metabolic functions, including oxidative phosphorylation (OXPHOS), the tricarboxylic acid cycle, and fatty acid and amino acid metabolism, in metabolic reprogramming of breast cancer cells. In addition, we outline the impact of mitochondrial dysfunction on metabolic pathways in different subtypes of breast cancer and mitochondrial inhibitors targeting different metabolic pathways, aiming to provide additional ideas for the development of mitochondrial inhibitors and to improve the efficacy of existing therapies for breast cancer.

Evaluation of IP3R3 Gene Silencing Effect on Pyruvate Dehydrogenase (PDH) Enzyme Activity in Breast Cancer Cells with and Without Estrogen Receptor

Background

Inositol 1,4,5-trisphosphate receptor (IP3R), a critical calcium ion (Ca2+) regulator, plays a vital role in breast cancer (BC) metabolism. Dysregulated IP3R in BC cells can drive abnormal growth or cell death. Estradiol increases IP3R type 3 (IP3R3) levels in BC, promoting cell proliferation and metabolic changes, including enhanced pyruvate dehydrogenase (PDH) activity, which, when reduced, leads to cell apoptosis. The study silenced IP3R3 to assess its impact on PDH.

Materials and Methods

The study used IP3R3 small interfering RNA (siRNA) to target Michigan Cancer Foundation-7 (MCF-7) and MDA-MB-231 cell lines. Transfection success was confirmed by flow cytometry. Cell viability and gene silencing were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and real-time quantitative polymerase chain reaction (PCR) assays. Protein expression and cellular activity were analyzed through western blotting and PDH activity measurement.

Results

Transfecting MCF-7 and MDA-MB-231 cells with IP3R3 siRNA achieved a 65% transfection rate without significant toxicity. IP3R3 gene silencing effectively reduced IP3R3 messenger RNA (mRNA) and protein levels in both cell lines, leading to decreased PDH enzyme activity, especially in MDA-MB-231 cells.

Conclusion

The study highlights a link between high IP3R3 gene silencing and reduced PDH activity, with higher IP3R3 expression in estrogen-independent (MDA-MB-231) compared to estrogen-dependent (MCF-7) cell lines. This suggests a potential impact on BC metabolism and tumor growth via regulation of PDH activity.

Lipid metabolism and its implications in tumor cell plasticity and drug resistance: what we learned thus far?

Metabolic reprogramming, a hallmark of cancer, allows cancer cells to adapt to their specific energy needs. The Warburg effect benefits cancer cells in both hypoxic and normoxic conditions and is a well-studied reprogramming of metabolism in cancer. Interestingly, the alteration of other metabolic pathways, especially lipid metabolism has also grabbed the attention of scientists worldwide. Lipids, primarily consisting of fatty acids, phospholipids and cholesterol, play essential roles as structural component of cell membrane, signalling molecule and energy reserves. This reprogramming primarily involves aberrations in the uptake, synthesis and breakdown of lipids, thereby contributing to the survival, proliferation, invasion, migration and metastasis of cancer cells. The development of resistance to the existing treatment modalities poses a major challenge in the field of cancer therapy. Also, the plasticity of tumor cells was reported to be a contributing factor for the development of resistance. A number of studies implicated that dysregulated lipid metabolism contributes to tumor cell plasticity and associated drug resistance. Therefore, it is important to understand the intricate reprogramming of lipid metabolism in cancer cells. In this review, we mainly focused on the implication of disturbed lipid metabolic events on inducing tumor cell plasticity-mediated drug resistance. In addition, we also discussed the concept of lipid peroxidation and its crucial role in phenotypic switching and resistance to ferroptosis in cancer cells. Elucidating the relationship between lipid metabolism, tumor cell plasticity and emergence of resistance will open new opportunities to develop innovative strategies and combinatorial approaches for the treatment of cancer.

The impact of poor metabolic health on aggressive breast cancer: adipose tissue and tumor metabolism

Obesity and type 2 diabetes are chronic metabolic diseases that impact tens to hundreds of millions of adults, especially in developed countries. Each condition is associated with an elevated risk of breast cancer and with a poor prognosis after treatment. The mechanisms connecting poor metabolic health to breast cancer are numerous and include hyperinsulinemia, inflammation, excess nutrient availability, and adipose tissue dysfunction. Here, we focus on adipose tissue, highlighting important roles for both adipocytes and fibroblasts in breast cancer progression. One potentially important mediator of adipose tissue effects on breast cancer is the fibroblast growth factor receptor (FGFR) signaling network. Among the many roles of FGFR signaling, we postulate that key mechanisms driving aggressive breast cancer include epithelial-to-mesenchymal transition and cellular metabolic reprogramming. We also pose existing questions that may help better understand breast cancer biology in people with obesity, type 2 diabetes, and poor metabolic health.

Epigenetic-Metabolic Interplay in the DNA Damage Response and Therapeutic Resistance of Breast Cancer

Therapy resistance is imposing a daunting challenge on effective clinical management of breast cancer. Although the development of resistance to drugs is multifaceted, reprogramming of energy metabolism pathways is emerging as a central but heterogenous regulator of this therapeutic challenge. Metabolic heterogeneity in cancer cells is intricately associated with alterations of different signaling networks and activation of DNA damage response pathways. Here we consider how the dynamic metabolic milieu of cancer cells regulates their DNA damage repair ability to ultimately contribute to development of therapy resistance. Diverse epigenetic regulators are crucial in remodeling the metabolic landscape of cancer. This epigenetic-metabolic interplay profoundly affects genomic stability of the cancer cells as well as their resistance to genotoxic therapies. These observations identify defining mechanisms of cancer epigenetics-metabolism-DNA repair axis that can be critical for devising novel, targeted therapeutic approaches that could sensitize cancer cells to conventional treatment strategies.

Modulating Glycolysis to Improve Cancer Therapy

Cancer cells undergo metabolic reprogramming and switch to a 'glycolysis-dominant' metabolic profile to promote their survival and meet their requirements for energy and macromolecules. This phenomenon, also known as the 'Warburg effect,' provides a survival advantage to the cancer cells and make the tumor environment more pro-cancerous. Additionally, the increased glycolytic dependence also promotes chemo/radio resistance. A similar switch to a glycolytic metabolic profile is also shown by the immune cells in the tumor microenvironment, inducing a competition between the cancer cells and the tumor-infiltrating cells over nutrients. Several recent studies have shown that targeting the enhanced glycolysis in cancer cells is a promising strategy to make them more susceptible to treatment with other conventional treatment modalities, including chemotherapy, radiotherapy, hormonal therapy, immunotherapy, and photodynamic therapy. Although several targeting strategies have been developed and several of them are in different stages of pre-clinical and clinical evaluation, there is still a lack of effective strategies to specifically target cancer cell glycolysis to improve treatment efficacy. Herein, we have reviewed our current understanding of the role of metabolic reprogramming in cancer cells and how targeting this phenomenon could be a potential strategy to improve the efficacy of conventional cancer therapy.

Phytochemical Targeting of Mitochondria for Breast Cancer Chemoprevention, Therapy, and Sensitization

Breast cancer is a common and deadly disease that causes tremendous physical, emotional, and financial burden on patients and society. Early-stage breast cancer and less aggressive subtypes have promising prognosis for patients, but in aggressive subtypes, and as cancers progress, treatment options and responses diminish, dramatically decreasing survival. Plants are nutritionally rich and biologically diverse organisms containing thousands of metabolites, some of which have chemopreventive, therapeutic, and sensitizing properties, providing a rich source for drug discovery. In this study we review the current landscape of breast cancer with a central focus on the potential role of phytochemicals for treatment, management, and disease prevention. We discuss the relevance of phytochemical targeting of mitochondria for improved anti-breast cancer efficacy. We highlight current applications of phytochemicals and derivative structures that display anti-cancer properties and modulate cancer mitochondria, while describing future applicability and identifying areas of promise.