BRCA1 and Breast Cancer: Molecular Mechanisms and Therapeutic Strategies

Enhancing therapeutic efficacy: sustained delivery of 5-fluorouracil (5-FU) via thiolated chitosan nanoparticles targeting CD44 in triple-negative breast cancer

Our current study reports the successful synthesis of thiolated chitosan-based nanoparticles for targeted drug delivery of 5-Fluorouracil. This process was achieved through the ionic gelation technique, aiming to improve the efficacy of the chemotherapeutic moiety by modifying the surface of the nanoparticles (NPs) with a ligand. We coated these NPs with hyaluronic acid (HA) to actively target the CD44 receptor, which is frequently overexpressed in various solid malignancies, including breast cancer. XRD, FTIR, SEM, and TEM were used for the physicochemical analysis of the NPs. These 5-Fluorouracil (5-FU) loaded NPs were evaluated on MDA-MB-231 (a triple-negative breast cell line) and MCF-10A (normal epithelial breast cells) to determine their in vitro efficacy. The developed 5-FU-loaded NPs exhibited a particle size within a favorable range (< 300 nm). The positive zeta potential of these nanoparticles facilitated their uptake by negatively charged cancer cells. Moreover, they demonstrated robust stability and achieved high encapsulation efficiency. These nanoparticles exhibited significant cytotoxicity compared to the crude drug (p < 0.05) and displayed a promising release pattern consistent with the basic diffusion model. These traits improve the pharmacokinetic profile, efficacy, and ability to precisely target these nanoparticles, offering a potentially successful anticancer treatment for breast cancer. However, additional in vivo assessments of these formulations are obligatory to confirm these findings.

The Molecular Detection of Germline Mutations in the BRCA1 and BRCA2 Genes Associated with Breast and Ovarian Cancer in a Romanian Cohort of 616 Patients

The objective of this study was to identify and classify the spectrum of mutations found in the BRCA1 and BRCA2 genes associated with breast and ovarian cancer in female patients in Romania. Germline BRCA1 and BRCA2 mutations were investigated in a cohort of 616 female patients using NGS and/or MLPA methods followed by software-based data analysis and classification according to international guidelines. Out of the 616 female patients included in this study, we found that 482 patients (78.2%) did not have any mutation present in the two genes investigated; 69 patients (11.2%) had a BRCA1 mutation, 34 (5.5%) had a BRCA2 mutation, and 31 (5%) presented different type of mutations with uncertain clinical significance, moderate risk or a large mutation in the BRCA1 gene. Our investigation indicates the most common mutations in the BRCA1 and BRCA2 genes, associated with breast and ovarian cancer in the Romanian population. Our results also bring more data in support of the frequency of the c.5266 mutation in the BRCA1 gene, acknowledged in the literature as a founder mutation in Eastern Europe. We consider that the results of our study will provide necessary data regarding BRCA1 and BRCA2 mutations that would help to create a genetic database for the Romanian population.

Toxoplasma gondii suppresses proliferation and migration of breast cancer cells by regulating their transcriptome

BACKGROUND

Breast cancer is the most common cancer in women worldwide. Toxoplasma gondii (T. gondii) has shown anticancer activity in breast cancer mouse models, and exerted beneficial effect on the survival of breast cancer patients, but the mechanism was unclear.

METHODS

The effect of tachyzoites of T. gondii (RH and ME49 strains) on human breast cancer cells (MCF-7 and MDA-MB-231 cells) proliferation and migration was assessed using cell growth curve and wound healing assays. Dual RNA-seq was performed for T. gondii-infected and non-infected cells to determine the differentially expressed genes (DEGs). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Protein-Protein Interaction Networks analysis (PPI) were performed to explore the related signaling pathway and hub genes. Hub genes were validated using the Kaplan-Meier plotter database, and Pathogen Host Interaction (PHI-base) database. The results were verified by qRT-PCR.

RESULTS

The tachyzoites of T. gondii decreased the expression of Ki67 and increased the expression of E-cadherin, resulting in suppressing the proliferation and migration of infected human breast cancer cells. The inhibitory effect of T. gondii on breast cancer cells showed a significant dose-response relationship. Compared with the control group, 2321 genes were transcriptionally regulated in MCF-7 cells infected with T. gondii, while 169 genes were transcriptionally regulated in infected MDA-MB-231 cells. Among these genes, 698 genes in infected MCF-7 cells and 67 genes in infected MDA-MB-231 cells were validated by the publicly available database. GO and KEGG analyses suggested that several pathways were involved in anticancer function of T. gondii, such as ribosome, interleukin-17 signaling, coronavirus disease pathway, and breast cancer pathway. BRCA1, MYC and IL-6 were identified as the top three hub genes in infected-breast cancer cells based on the connectivity of PPI analysis. In addition, after interacting with breast cancer cells, the expression of ROP16 and ROP18 in T. gondii increased, while the expression of crt, TgIST, GRA15, GRA24 and MIC13 decreased.

CONCLUSIONS

T. gondii transcriptionally regulates several signaling pathways by altering the hub genes such as BRCA1, MYC and IL-6, which can inhibit the breast tumor growth and migration, hinting at a potential therapeutic strategy.

Optimizing therapeutic targets for breast cancer using boolean network models

Studying gene regulatory networks associated with cancer provides valuable insights for therapeutic purposes, given that cancer is fundamentally a genetic disease. However, as the number of genes in the system increases, the complexity arising from the interconnections between network components grows exponentially. In this study, using Boolean logic to adjust the existing relationships between network components has facilitated simplifying the modeling process, enabling the generation of attractors that represent cell phenotypes based on breast cancer RNA-seq data. A key therapeutic objective is to guide cells, through targeted interventions, to transition from the current cancer attractor to a physiologically distinct attractor unrelated to cancer. To achieve this, we developed a computational method that identifies network nodes whose inhibition can facilitate the desired transition from one tumor attractor to another associated with apoptosis, leveraging transcriptomic data from cell lines. To validate the model, we utilized previously published in vitro experiments where the downregulation of specific proteins resulted in cell growth arrest and death of a breast cancer cell line. The method proposed in this manuscript combines diverse data sources, conducts structural network analysis, and incorporates relevant biological knowledge on apoptosis in cancer cells. This comprehensive approach aims to identify potential targets of significance for personalized medicine.

Cost-Effectiveness Analysis of Adjuvant Olaparib Versus Watch and Wait in the Treatment of Germline BRCA1/2-Mutated, High-Risk, HER2-Negative Early Breast Cancer in Sweden

INTRODUCTION

This study evaluated the cost effectiveness of adjuvant olaparib versus watch and wait (WaW) in patients with germline breast cancer susceptibility gene 1/2 (gBRCA1/2)-mutated, high-risk, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer (eBC), previously treated with neoadjuvant or adjuvant chemotherapy, from a Swedish healthcare perspective.

METHODS

A five-state (invasive disease-free survival [IDFS], non-metastatic breast cancer [non-mBC], early-onset mBC, late-onset mBC, death) semi-Markov state transition model with a lifetime horizon was developed. Transition probabilities were informed by data from the Phase III OlympiA trial, supplemented with data from additional studies in BRCA-mutated, HER2-negative mBC. Health state utilities were derived via mapping of OlympiA data and supplemented by literature estimates. Treatment, adverse events and other medical costs were extracted from publicly available Swedish sources. Incremental cost per life-year (LY) and quality-adjusted life-year (QALY) gained were estimated. Costs and outcomes were discounted at 3% annually. One-way deterministic and probabilistic sensitivity analyses (PSA) were conducted.

RESULTS

Over a lifetime horizon, adjuvant olaparib was associated with an additional 1.50 LYs and 1.22 QALYs, and incremental cost of 471,156 Swedish krona (SEK) versus WaW (discounted). The resulting ICER was 385,183SEK per QALY gained for olaparib versus WaW. ICERs remained below 1,000,000SEK across a range of scenarios, and were consistent across subgroups (hormone receptor [HR]-positive/HER2-negative and triple-negative breast cancer [TNBC]). In PSA, the probability of olaparib being cost effective at 1,000,000SEK per QALY was 99.8%.

CONCLUSIONS

At list price, adjuvant olaparib is a cost-effective alternative to WaW in patients with gBRCA1/2-mutated, high-risk, HER2-negative eBC in Sweden.

A network-based drug prioritization and combination analysis for the MEK5/ERK5 pathway in breast cancer

BACKGROUND

Prioritizing candidate drugs based on genome-wide expression data is an emerging approach in systems pharmacology due to its holistic perspective for preclinical drug evaluation. In the current study, a network-based approach was proposed and applied to prioritize plant polyphenols and identify potential drug combinations in breast cancer. We focused on MEK5/ERK5 signalling pathway genes, a recently identified potential drug target in cancer with roles spanning major carcinogenesis processes.

RESULTS

By constructing and identifying perturbed protein-protein interaction networks for luminal A breast cancer, plant polyphenols and drugs from transcriptome data, we first demonstrated their systemic effects on the MEK5/ERK5 signalling pathway. Subsequently, we applied a pathway-specific network pharmacology pipeline to prioritize plant polyphenols and potential drug combinations for use in breast cancer. Our analysis prioritized genistein among plant polyphenols. Drug combination simulations predicted several FDA-approved drugs in breast cancer with well-established pharmacology as candidates for target network synergistic combination with genistein. This study also highlights the concept of target network enhancer drugs, with drugs previously not well characterised in breast cancer being prioritized for use in the MEK5/ERK5 pathway in breast cancer.

CONCLUSION

This study proposes a computational framework for drug prioritization and combination with the MEK5/ERK5 signaling pathway in breast cancer. The method is flexible and provides the scientific community with a robust method that can be applied to other complex diseases.

Onco-Breastomics: An Eco-Evo-Devo Holistic Approach

Known as a diverse collection of neoplastic diseases, breast cancer (BC) can be hyperbolically characterized as a dynamic pseudo-organ, a living organism able to build a complex, open, hierarchically organized, self-sustainable, and self-renewable tumor system, a population, a species, a local community, a biocenosis, or an evolving dynamical ecosystem (i.e., immune or metabolic ecosystem) that emphasizes both developmental continuity and spatio-temporal change. Moreover, a cancer cell community, also known as an oncobiota, has been described as non-sexually reproducing species, as well as a migratory or invasive species that expresses intelligent behavior, or an endangered or parasite species that fights to survive, to optimize its features inside the host's ecosystem, or that is able to exploit or to disrupt its host circadian cycle for improving the own proliferation and spreading. BC tumorigenesis has also been compared with the early embryo and placenta development that may suggest new strategies for research and therapy. Furthermore, BC has also been characterized as an environmental disease or as an ecological disorder. Many mechanisms of cancer progression have been explained by principles of ecology, developmental biology, and evolutionary paradigms. Many authors have discussed ecological, developmental, and evolutionary strategies for more successful anti-cancer therapies, or for understanding the ecological, developmental, and evolutionary bases of BC exploitable vulnerabilities. Herein, we used the integrated framework of three well known ecological theories: the Bronfenbrenner's theory of human development, the Vannote's River Continuum Concept (RCC), and the Ecological Evolutionary Developmental Biology (Eco-Evo-Devo) theory, to explain and understand several eco-evo-devo-based principles that govern BC progression. Multi-omics fields, taken together as onco-breastomics, offer better opportunities to integrate, analyze, and interpret large amounts of complex heterogeneous data, such as various and big-omics data obtained by multiple investigative modalities, for understanding the eco-evo-devo-based principles that drive BC progression and treatment. These integrative eco-evo-devo theories can help clinicians better diagnose and treat BC, for example, by using non-invasive biomarkers in liquid-biopsies that have emerged from integrated omics-based data that accurately reflect the biomolecular landscape of the primary tumor in order to avoid mutilating preventive surgery, like bilateral mastectomy. From the perspective of preventive, personalized, and participatory medicine, these hypotheses may help patients to think about this disease as a process governed by natural rules, to understand the possible causes of the disease, and to gain control on their own health.

Target-based drug discovery: Applications of fluorescence techniques in high throughput and fragment-based screening

Target-based discovery of first-in-class therapeutics demands an in-depth understanding of the molecular mechanisms underlying human diseases. Precise measurements of cellular and biochemical activities are critical to gain mechanistic knowledge of biomolecules and their altered function in disease conditions. Such measurements enable the development of intervention strategies for preventing or treating diseases by modulation of desired molecular processes. Fluorescence-based techniques are routinely employed for accurate and robust measurements of in-vitro activity of molecular targets and for discovering novel chemical molecules that modulate the activity of molecular targets. In the current review, the authors focus on the applications of fluorescence-based high throughput screening (HTS) and fragment-based ligand discovery (FBLD) techniques such as fluorescence polarization (FP), Förster resonance energy transfer (FRET), fluorescence thermal shift assay (FTSA) and microscale thermophoresis (MST) for the discovery of chemical probe to exploring target's role in disease biology and ultimately, serve as a foundation for drug discovery. Some recent advancements in these techniques for compound library screening against important classes of drug targets, such as G-protein-coupled receptors (GPCRs) and GTPases, as well as phosphorylation- and acetylation-mediated protein-protein interactions, are discussed. Overall, this review presents a landscape of how these techniques paved the way for the discovery of small-molecule modulators and biologics against these targets for therapeutic benefits.

Conditional in vivo deletion of LYN kinase has little effect on a BRCA1 loss-of-function-associated mammary tumour model

LYN kinase is expressed in BRCA1 loss-of-function-dependent mouse mammary tumours, in the cells of origin of such tumours, and in human breast cancer. Suppressing LYN kinase activity in BRCA1-defective cell lines as well as in in vitro cultures of Brca1-null mouse mammary tumours is deleterious to their growth. Here, we examined the interaction between LYN kinase and BRCA1 loss-of-function in an in vivo mouse mammary tumour model, using conditional knockout Brca1 and Lyn alleles. Comparison of Brca1 tumour cohorts showed little difference in mammary tumour formation between animals that were wild type, heterozygous or homozygous for the conditional Lyn allele, although this was confounded by factors including incomplete Lyn recombination in some tumours. RNA-sequencing analysis demonstrated that tumours with high levels of Lyn gene expression had a slower doubling time, but this was not correlated with levels of LYN staining in tumour cells themselves. Rather, high Lyn expression and slower tumour growth were likely a result of B-cell infiltration. The multifaceted role of LYN indicates that it is likely to present difficulties as a therapeutic target in breast cancer.

Current Status of Cancer Genomics and Imaging Phenotypes: What Radiologists Need to Know

Ongoing discoveries in cancer genomics and epigenomics have revolutionized clinical oncology and precision health care. This knowledge provides unprecedented insights into tumor biology and heterogeneity within a single tumor, among primary and metastatic lesions, and among patients with the same histologic type of cancer. Large-scale genomic sequencing studies also sparked the development of new tumor classifications, biomarkers, and targeted therapies. Because of the central role of imaging in cancer diagnosis and therapy, radiologists need to be familiar with the basic concepts of genomics, which are now becoming the new norm in oncologic clinical practice. By incorporating these concepts into clinical practice, radiologists can make their imaging interpretations more meaningful and specific, facilitate multidisciplinary clinical dialogue and interventions, and provide better patient-centric care. This review article highlights basic concepts of genomics and epigenomics, reviews the most common genetic alterations in cancer, and discusses the implications of these concepts on imaging by organ system in a case-based manner. This information will help stimulate new innovations in imaging research, accelerate the development and validation of new imaging biomarkers, and motivate efforts to bring new molecular and functional imaging methods to clinical radiology. Keywords: Oncology, Cancer Genomics, Epignomics, Radiogenomics, Imaging Markers Supplemental material is available for this article. © RSNA, 2023.

The RANK-RANKL-OPG System: A Multifaceted Regulator of Homeostasis, Immunity, and Cancer

The RANK-RANKL-OPG system is a complex signaling pathway that plays a critical role in bone metabolism, mammary epithelial cell development, immune function, and cancer. RANKL is a ligand that binds to RANK, a receptor expressed on osteoclasts, dendritic cells, T cells, and other cells. RANKL signaling promotes osteoclast differentiation and activation, which leads to bone resorption. OPG is a decoy receptor that binds to RANKL and inhibits its signaling. In cancer cells, RANKL expression is often increased, which can lead to increased bone resorption and the development of bone metastases. RANKL-neutralizing antibodies, such as denosumab, have been shown to be effective in the treatment of skeletal-related events, including osteoporosis or bone metastases, and cancer. This review will provide a comprehensive overview of the functions of the RANK-RANKL-OPG system in bone metabolism, mammary epithelial cells, immune function, and cancer, together with the potential therapeutic implications of the RANK-RANKL pathway for cancer management.

Allo: Accurate allocation of multi-mapped reads enables regulatory element analysis at repeats

Transposable elements (TEs) and other repetitive regions have been shown to contain gene regulatory elements, including transcription factor binding sites. Unfortunately, regulatory elements harbored by repeats have proven difficult to characterize using short-read sequencing assays such as ChIP-seq or ATAC-seq. Most regulatory genomics analysis pipelines discard "multi-mapped" reads that align equally well to multiple genomic locations. Since multi-mapped reads arise predominantly from repeats, current analysis pipelines fail to detect a substantial portion of regulatory events that occur in repetitive regions. To address this shortcoming, we developed Allo, a new approach to allocate multi-mapped reads in an efficient, accurate, and user-friendly manner. Allo combines probabilistic mapping of multi-mapped reads with a convolutional neural network that recognizes the read distribution features of potential peaks, offering enhanced accuracy in multi-mapping read assignment. Allo also provides read-level output in the form of a corrected alignment file, making it compatible with existing regulatory genomics analysis pipelines and downstream peak-finders. In a demonstration application on CTCF ChIP-seq data, we show that Allo results in the discovery of thousands of new CTCF peaks. Many of these peaks contain the expected cognate motif and/or serve as TAD boundaries. We additionally apply Allo to a diverse collection of ENCODE ChIP-seq datasets, resulting in multiple previously unidentified interactions between transcription factors and repetitive element families. Finally, we show that Allo may be particularly effective in identifying ChIP-seq peaks in younger TEs, which hold evolutionary significance due to their emergence during human evolution from primates.

The Tumor Suppressor BRCA1/2, Cancer Susceptibility and Genome Instability in Gynecological and Mammary Cancers

BRCA1 and BRCA2 germline alterations highly predispose women to breast and ovarian cancers. They are mostly found within the TNBC (Triple-Negative Breast Cancer) and the HGSOC (High-Grade Serous Ovarian Carcinoma) subsets, known by an aggressive phenotype, the lack of therapeutic targets and poor prognosis. Importantly, there is an increased risk for cervical cancer in BRCA1 and BRCA2 mutation carriers that raises questions about the link between the HPV-driven genome instability and BRCA1 and BRCA2 germline mutations. Clinical, preclinical, and in vitro studies explained the increased risk for breast and ovarian cancers by genome instability resulting from the lack or loss of many functions related to BRCA1 or BRCA2 proteins such as DNA damage repair, stalled forks and R-loops resolution, transcription regulation, cell cycle control, and oxidative stress. In this review, we decipher the relationship between BRCA1/2 alterations and genomic instability leading to gynecomammary cancers through results from patients, mice, and cell lines. Understanding the early events of BRCA1/2-driven genomic instability in gynecomammary cancers would help to find new biomarkers for early diagnosis, improve the sensitivity of emerging therapies such as PARP inhibitors, and reveal new potential therapeutic targets.

Deciphering Common Traits of Breast and Ovarian Cancer Stem Cells and Possible Therapeutic Approaches

Breast cancer (BC) and ovarian cancer (OC) are among the most common and deadly cancers affecting women worldwide. Both are complex diseases with marked heterogeneity. Despite the induction of screening programs that increase the frequency of earlier diagnosis of BC, at a stage when the cancer is more likely to respond to therapy, which does not exist for OC, more than 50% of both cancers are diagnosed at an advanced stage. Initial therapy can put the cancer into remission. However, recurrences occur frequently in both BC and OC, which are highly cancer-subtype dependent. Therapy resistance is mainly attributed to a rare subpopulation of cells, named cancer stem cells (CSC) or tumor-initiating cells, as they are capable of self-renewal, tumor initiation, and regrowth of tumor bulk. In this review, we will discuss the distinctive markers and signaling pathways that characterize CSC, their interactions with the tumor microenvironment, and the strategies they employ to evade immune surveillance. Our focus will be on identifying the common features of breast cancer stem cells (BCSC) and ovarian cancer stem cells (OCSC) and suggesting potential therapeutic approaches.

RANKL and RANK in Cancer Therapy

Receptor activator of nuclear factor-κB (RANK) and its ligand (RANKL) are key regulators of mammalian physiology such as bone metabolism, immune tolerance and antitumor immunity, and mammary gland biology. Here, we explore the multiple functions of RANKL/RANK in physiology and pathophysiology and discuss underlying principles and strategies to modulate the RANKL/RANK pathway as a therapeutic target in immune-mediated cancer treatment.

Prospects for limiting access to prenatal genetic information about Down syndrome in light of the expansion of prenatal genomics

Down syndrome (Trisomy 21) is a mild to moderate intellectual disability. Historically, this condition has been a primary target for prenatal testing. However, Down syndrome has not been targeted for prenatal testing because it is an especially severe illness. The condition was just one that could be easily identified prenatally using the techniques first available decades ago. We are moving into an era in which we can prenatally test for a vast range of human traits. I argue that when we can test for anything, there is no longer any reason to continue targeting Down syndrome. I present an argument based on the value of nondiscrimination. It is justified to set limits on access to prenatal information if the information is going to be used for discriminatory purposes. I use the examples of (1) prenatal testing for misogynistic fetal sex selection, and (2) homophobia-motivated prenatal testing for potential homosexuality, as compelling analogies.

Oral Contraceptive Use and Breast Cancer Risk for BRCA1 and BRCA2 Mutation Carriers: Systematic Review and Meta-Analysis of Case–Control Studies

Oral contraceptive use is one of the major modifiable risk factors for breast cancer. To investigate the effect of oral contraceptive taking on breast cancer risk by BRCA 1 and BRCA 2 mutation status, we conducted a systematic review and meta-analysis of case-controlled studies. Therefore, English language articles were retrieved by searching MEDLINE (PubMed), EMBASE and the Cochrane Library up to August 2021. Data were pooled from none case–control studies, comprising a total of 33,162 subjects, including 23,453 who had never used oral contraceptives. Overall meta-analysis indicated a statistically insignificant risk reduction: OR = 0.86, 95% CI: 0.70 to 1.06, p = 0.1594. However, increased breast cancer risk was associated with age at first use of OCs ≥20 years: OR = 1.21, 95% CI:1.07 to 1.36, p = 0.002. Multivariable meta-regression with covariates of age of first OC use (β = 0.21, 95% CI: −0.25 to 0.67, p = 0.3767), duration of OC use (β = −0.08, 95% CI; −0.51 to 0.34, p = 0.7093), and time since last OC use (β = 0.32, 95% CI: −0.22 to 0.85, p = 0.2461) did not have a significant effect on the breast cancer risk. This meta-analysis suggests a diverse effect of oral contraceptive use against breast cancer in BRCA carrier mutation. The association between OC use and breast and ovarian cancers needs more investigation.