Is the differentiation into molecular subtypes of breast cancer important for staging, local and systemic therapy, and follow up?

Potentiating Antibody-Dependent Cellular Cytotoxicity in Triple-Negative Breast Cancer via the Humanized Anti-CD147 Antibody

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype with high metastatic potential, poor prognosis, and the absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2). The lack of these receptors limits the standard treatments, such as hormone therapies and HER2-targeted antibodies like trastuzumab. These challenges highlight the critical need for novel therapeutic strategies. CD147, a transmembrane glycoprotein overexpressed in TNBC, promotes tumor progression, metastasis, and chemoresistance, making it a promising therapeutic target. This study evaluates the antibody-dependent cellular cytotoxicity (ADCC) of HuM6-1B9, a humanized anti-CD147 antibody, against MDA-MB-231 cells, a TNBC model.

METHODS

CFSE-labelled MDA-MB-231 cells were co-cultured with PBMCs as effector cells (E:T ratio 80:1) in the presence of HuM6-1B9 and incubated for 4 h. Cells were then collected and stained with PI, and CFSE+/PI+ dead target cells were analyzed by flow cytometry.

RESULTS

Co-culturing MDA-MB-231 cells with peripheral blood mononuclear cells (PBMCs) in the presence of HuM6-1B9 demonstrated effective ADCC induction without direct cytotoxicity. HuM6-1B9 induced 54.01% cancer cell death via ADCC, significantly outperforming trastuzumab (26.14%) while sparing PBMCs.

CONCLUSION

These findings support HuM6-1B9 as a prospective TNBC therapeutic and warrant further investigation into its clinical potential.

Genetic Alterations in HER2-Positive and Equivocal Breast Cancer by Immunohistochemistry

Purpose

We aimed to identify genetic alterations in groups with different HER2 immunohistochemical (IHC) scores.

Patients and Methods

A total of 120 patients with HER2-positive breast cancers, including 89 cases with IHC 3+ tumors and 31 cases with IHC 2+ and positive for in situ hybridization (ISH) were enrolled. Molecular profiles were determined using Thermo Fisher TMO comprehensive assay on surgically removed tissues. All called variants were compared between IHC3+ and IHC2+/ISH+ groups by Fisher exact test.

Results

There was a significantly higher sample frequency 94.4% (84/89) of ERBB2 amplification in IHC3+ group than that in IHC2+/ISH+ group 45.2% (14/31). By contrast, there was a significantly lower sample frequency of MYC_AMP_CNA 10.1% (9/89) and CCND3_AMP_CNA 0% (0/89) in IHC3+ group than those in IHC2+/ISH+ group with sample frequency 25.8% (8/31), and 9.7% (3/31), respectively.

Conclusion

We conclude that HER2 IHC3+ tumors have higher frequency of ERBB2_ AMP_CNA and lower frequency of CCND3_ AMP_CNA and MYC_AMP_CNA than IHC2+/ISH+ tumors. These results provide therapeutic strategies in treatment of HER2-positive breast cancer.

Correlation Between PIK3R1 Expression and Cell Growth in Human Breast Cancer Cell Line BT-474 and Clinical Outcomes

Background

While mutations in the PIK3CA gene play important roles in human breast carcinogenesis, PIK3R1 gene alterations are recognized as actionable mutations for clinical cancer treatment. We aimed to elucidate the role of PIK3R1 in cell proliferation on breast carcinoma and to correlate the PIK3R1 expression with patients' outcome using human tumor tissue arrays.

Methods

Using human BT-474 (estrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2)-high) breast carcinoma cell line as in vitro model, the role of PIK3R1 in cell proliferation was elucidated by knock-down of the PIK3R1 gene (ΔPIK3R1) in this cell line. Between January 2000 to December 2015, the records of a cohort of 440 patients in our hospital were retrospectively reviewed, including patients' survival. The correlations between PIK3R1 expression and patient prognosis, such as overall survival (OS) and disease-free survival (DFS), were elucidated by human breast cancer tumor tissue array immunostaining.

Results

After the PIK3R1 gene was silenced in the BT-474 line, there was an increased cell number and a decrease in the G0G1-fraction, and increased S-fraction and the S+G2M-fraction for the ΔPIK3R1-BT-474 cell line, as compared to their cell wild type (WT) line. Western blot analysis showed that decreased PIK3R1 protein levels were accompanied by an increase of the p-AKT and p-mTOR proteins in the ΔPIK3R1-BT-474 cell line, compared to the equivalent WT line. Using a human tumor tissue array, patients with high-expressed PIK3R1 protein had better outcomes in terms of DFS and OS, compared to those with low-expressed PIK3R1 protein, when breast cancer was at an early stage (stage I/II), but not across all stages of breast cancer in human patients.

Conclusions

We concluded that downregulated PIK3R1 in BT-474 cells resulted in an increased cell growth and upregulated AKT-mTOR signaling. Clinically, the high-expressed PIK3R1 protein in tumors correlates positively with patients' outcome in stage I and II breast cancer.

Follow-up of early breast cancer in a public health system: A 2024 AIGOM consensus project

Breast cancer stands as the most frequently diagnosed cancer and the primary cause of cancer-related mortality among women worldwide, including Italy. With the increasing number of survivors, many are enrolled in regular follow-up programs. However, adherence to recommendations from scientific societies (such as ASCO, ESMO, AIOM) for breast cancer follow-up management varies in daily clinical practice across different cancer centers, potentially resulting in unequal management and escalating costs. To address these concerns, the Italian Association of Multidisciplinary Oncology Groups (AIGOM) orchestrated a Consensus on early Breast Cancer follow-up utilizing the Estimate-Talk-Estimate methodology. Following the identification of 18 Items and 38 statements by a select Board, 46 out of 54 (85.1%) experts comprising a multidisciplinary and multiprofessional panel expressed their degree of consensus (Expert Panel). The Expert Panel underscores the potential for the multidisciplinary team to tailor follow-up intensity based on the individual risk of recurrence. In selected cases, the general practitioner may be recommended as the clinical lead for breast cancer follow-up, both after completion of adjuvant treatment and at early initiation of endocrine therapy in low-risk patients. Throughout follow-up, and alongside oncologic surveillance, the expert panel advises osteometabolic, cardiologic, and gynecologic surveillance for the early detection and management of early and late treatment toxicities. Moreover, preserving quality of life is emphasized, with provisions for psycho-oncologic support and encouragement to adopt protective lifestyle behaviors.

Exploring SALL4 as a significant prognostic marker in breast cancer and its association with progression pathways involved in cancer genesis

Breast carcinoma is the leading factor in women's cancer-related fatalities. Due to its numerous inherent molecular subtypes, breast cancer is an extremely diverse illness. The human epidermal growth factor receptor 2 (HER2) positive subtypes stands out among these subtypes as being especially prone to cancer development and illness recurrence. The regulation of embryonic stem cells' pluripotency and self-renewal is carried out by the SALL4 (Spalt-like transcription factor 4) family member. Numerous molecular pathways operating at the transcriptional, post-transcriptional, and epigenomic levels regulate the expression of SALL4. Many transcription factors control the expression of SALL4, with STAT3 being the primary regulator in hepatocellular carcinoma (HCC) and breast carcinoma. Moreover, this oncogene has been connected to a number of cellular functions, including invasion, apoptosis, proliferation, and resistance to therapy. Reduced patient survival rates and a worse prognosis have been linked to higher levels of SALL4. In order to target the undruggable SALL4 that is overexpressed in breast carcinoma, we investigated the prognostic levels of SALL4 in breast carcinoma and its interaction with various related proteins. Using TIMER 2.0 analysis, the expression pattern of SALL4 was investigated across all TCGA datasets. The research revealed that SALL4 expression was elevated in various cancers. The UALCAN findings demonstrated that SALL4 was overexpressed in all tumor samples including breast cancer especially TNBC (Triple negative breast cancer). The web-based ENRICHR program was used for gene ontology analysis that revealed SALL4 was actively involved in the development of the nervous system, positive regulation of stem cell proliferation, regulation of stem cell proliferation, regulation of the activin receptor signaling pathway, regulation of transcription using DNA templates, miRNA metabolic processes, and regulation of transcription by RNA Polymerase I. Using the STRING database, we analyzed the interaction and involvement of SALL4 with other abruptly activated proteins and used Cytoscape 3.8.0 for visualization. Additionally, using bc-GenExMiner, we studied the impact of SALL4 on pathways abruptly activated in different breast cancer subtypes that revealed SALL4 was highly correlated with WNT2B, NOTCH4, AKT3, and PIK3CA. Furthermore, to target SALL4, we evaluated and analyzed the impact of CLP and its analogues, revealing promising outcomes.

The Multifaceted Roles of Myrrha in the Treatment of Breast Cancer: Potential Therapeutic Targets and Promises

BACKGROUND

Breast cancer is a critical threat to human health, and effective targeted agents showing lower systemic toxicity are still lacking. Therefore, exploring new potent therapeutic candidates with a broader safety margin is warranted. Alternative medicine, which has historically been used in traditional Chinese medicine, has played an increasingly prominent role in this area of research. This study introduces Commiphora myrrha (or myrrh) as a potential therapeutic candidate for treating breast cancer patients. Myrrh bioactive extracts have been used traditionally for decades to treat numerous medical disorders, including cancers, specifically breast cancer. Nonetheless, myrrh's precise rudimentary mechanisms of action in regulating genes involved in breast cancer evolution and progression remain elusive.

PURPOSE

Herein, we use a network pharmacology platform to identify the potential genes targeted by myrrh-active molecules in breast cancer.

METHOD

The identified targets' expression profiles were determined at the mRNA and protein levels using The Breast Cancer Gene-Expression Miner v5.0 (bcGen-ExMiner v5.0) and The Human Protein Atlas datasets, respectively. A gene signature composed of the specifically designated genes was constructed, and its association with different breast cancer molecular subtypes was investigated through the Gene expression-based Outcome for Breast Cancer (GOBO) online tool. The protein mapping relationship between potential myrrh targets and their partner proteins during breast cancer development was screened and constructed through the STRING and ShinyGO databases. In addition, the Kaplan-Meier plots (KM-plot) prognostic tool was applied to assess the survival rate associated with the expression of the current gene signature in different human cancers, including breast cancer.

RESULTS

Combining the results of network pharmacology with other bioinformatics databases suggests that myrrh's active components exert anti-cancer effects by regulating genes involved in breast cancer pathogenesis, particularly PTGS2, EGFR, ESR2, MMP2, and JUN. An individual evaluation of the expression profiles of these genes at both mRNA and protein levels reveals that a high expression profile of each gene is associated with breast cancer advancement. Moreover, the GOBO analysis shows an elevated expression profile of the PTGS2/ESR2/EGFR/JUN/MMP2 genes' signature in the most aggressive breast cancer subtype (Basal) in breast tumor samples and breast cancer cell lines. Furthermore, the STRING protein interaction network and the KEGG analyses indicate that myrrh exerts therapeutic effects on breast cancer by regulating several biological processes such as cell proliferation, cell migration, apoptosis, and various signaling pathways, including TNF, PI3K-Akt, NF-κB, and MAPK. Consistently, breast cancer patients with high expression of this genes' signature display poor survival outcomes.

CONCLUSIONS

The present study is the first attempt to explore the biological involvement of myrrh-targeted genes during breast cancer development. Therefore, suppressing the effects of the intended genes' signature using myrrh extracts would provide encouraging results in blocking breast cancer tumorigenesis. Thus, our findings provide conclusive evidence and deepen the current understanding of the molecular role of myrrh in the treatment of breast cancer, further supporting its clinical application.

Update on the Use of Molecular Subtyping in Breast Cancer

The standard of care for invasive cancers of the breast has been and continues to be to evaluate them for breast prognostic markers: estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 by immunohistochemistry. Over 2 decades ago, a study was the first to report on the molecular subtypes of breast cancer. Four main subtypes were reported. Since then there have been some changes in the molecular subtype classification, but overall many studies have shown that this subtyping has clinical prognostic and predictive value. More recently, molecular assays have been developed and studies have shown similar clinical prognostic and predictive value. We reviewed the literature for studies evaluating the clinical significance of all 3 of these methods of evaluation and the follow-up findings of that review are presented below.

Impact of the OncotypeDX score and HER2 RNA PCR levels on HER2-low IHC levels in primary and metastasized tumors

PURPOSE

One-half of hormone receptor-positive (HR +) breast cancer (BC) patients have low expression of HER2 (HER2-low) and may benefit from trastuzumab deruxtecan (TDXd). This study aimed to identify parameters associated with HER2-low levels in primary and metastatic tumors. We specifically sought to determine whether OncotypeDX and HER2 mRNA levels could identify patients who would otherwise be considered HER2-negative by immunohistochemistry (IHC).

METHODS

This retrospective analysis of all consecutive HR + patients who underwent OncotypeDX from January 2004 to December 2020 was conducted in a single medical center (n = 1429). We divided HER2-negative cases into HER2-low (IHC = 1 + or 2 + and non-amplified fluorescent situ hybridization) and HER2-0 (IHC = 0). HER2 RT-PCR was evaluated from the OncotypeDX results.

RESULTS

HER2-low cases exhibited significantly higher HER2 RT-PCR scores (p = 2.1e-9), elevated estrogen receptor (ER) levels (p = 0.0114), and larger tumor sizes compared to HER2-0 cases (> 2 cm; 36.6% vs. 22.1%, respectively, p < 0.00001). Primary tumors > 2 cm were more likely to be HER2-low (OR = 2.07, 95% CI: 1.6317 to 2.6475, p < 0.0001). Metastatic BCs expressed higher HER2 IHC scores compared with primary BCs (Wilcoxon signed-rank, p = 0.046). HER2 IHC scores were higher for low-risk vs. medium-risk OncotypeDX (p = 0.0067). No other clinical or pathological parameters were associated with the increase in HER2 levels in the metastatic samples.

CONCLUSION

It might be beneficial to use clinical data from the primary tumor, including the HER2 RT-PCR score, to determine a HER2-low status.

Origanum syriacum L. Attenuates the Malignant Phenotype of MDA-MB231 Breast Cancer Cells

Breast cancer is the leading cause of cancer-related deaths among women. Among breast cancer types, triple negative breast cancer (TNBC) is the most aggressive, and is resistant to hormonal and chemotherapeutic treatments. As such, alternative approaches that may provide some benefit in fighting this debilitating pathology are critically needed; hence the utilization of herbal medicine. Origanum syriacum L., one of the most regularly consumed plants in the Mediterranean region, exhibits antiproliferative effect on several cancer cell lines. However, whether this herb modulates the malignant phenotype of TNBC remains poorly investigated. Here, we show that in MDA-MB-231, a TNBC cell line, Origanum syriacum L. aqueous extract (OSE) inhibited cellular viability, induced autophagy determined by the accumulation of lipidized LC3 II, and triggered apoptosis. We also show that OSE significantly promoted homotypic cell-cell adhesion while it decreased cellular migration, adhesion to fibronectin, and invasion of MDA-MB-231 cells. This was supported by decreased activity of focal adhesion kinase (FAK), reduced α2 integrin expression, and downregulation of secreted PgE2, MMP2 and MMP-9, in OSE-treated cells. Finally, we also show that OSE significantly inhibited angiogenesis and downregulated the level of nitric oxide (NO) production. Our findings demonstrate the ability of OSE to attenuate the malignant phenotype of the MDA-MB-231 cells, thus presenting Origanum syriacum L. as a promising potential source for therapeutic compounds for TNBC.

Melissa officinalis L. bitkisinin apoptoz ve otofaji yoluyla insan meme kanser hücre hattı üzerine etkisi

Amaç: Bu araştırmanın amacı, Melissa officinalis L. bitkisinin in vitro olarak MCF-7 meme kanseri hücrelerindeki ölüm yollarını nasıl etkilediğini görmektir. Gereç ve Yöntem: Melissa officinalis bitkisinin topraküstü kısımlarından hazırlanan %70 metanolik ekstrenin sitotoksik aktivitesi ve IC50 değerini belirlemek için MCF-7 meme kanseri hücre hattı farklı konsantrasyonlar da ve sürelerde Melissa officinalis’ e maruz bırakılarak MTT analizi yapıldı. Melissa officinalis' in belirlenen IC50 dozunda meme kanseri hücreleri üzerindeki apoptotik etkileri TUNEL yöntemi ile, otofajik etkileri Beclin-1 ve LC3 immünofloresan boyama yöntemi kullanılarak ortaya çıkarıldı. Bulgular: Melissa officinalis’ in, MCF-7 meme kanseri hücreleri üzerindeki etkileri değerlendirildiğinde, MCF-7 meme kanseri hücre hattındaki hücre canlılığını doza ve zamana bağlı bir şekilde azalttığı görüldü. Bunun yanı sıra, apopitozu indüklediği ve otofaji belirteçleri olan Beclin-1 ve LC3 immunreaktivitesini de artırdığı gözlendi. Sonuç: Çalışmadan elde edilen bulgular, Melissa officinalis’in hem apoptoz hem de otofaji hücre ölümü yolları üzerinden MCF-7 meme kanseri hücreleri üzerinde sitotoksik bir etkiye sahip olduğunu göstermiştir. Bu veriler, antitümör etki mekanizmasını aydınlatmak için gerekli olan daha ileri in vitro çalışmalara öncülük edecektir.

ETV7 regulates breast cancer stem-like cell features by repressing IFN-response genes

Cancer stem cells (CSCs) represent a population of cells within the tumor able to drive tumorigenesis and known to be highly resistant to conventional chemotherapy and radiotherapy. In this work, we show a new role for ETV7, a transcriptional repressor member of the ETS family, in promoting breast cancer stem-like cells plasticity and resistance to chemo- and radiotherapy in breast cancer (BC) cells. We observed that MCF7 and T47D BC-derived cells stably over-expressing ETV7 showed reduced sensitivity to the chemotherapeutic drug 5-fluorouracil and to radiotherapy, accompanied by an adaptive proliferative behavior observed in different culture conditions. We further noticed that alteration of ETV7 expression could significantly affect the population of breast CSCs, measured by CD44⁺/CD24^low cell population and mammosphere formation efficiency. By transcriptome profiling, we identified a signature of Interferon-responsive genes significantly repressed in cells over-expressing ETV7, which could be responsible for the increase in the breast CSCs population, as this could be partially reverted by the treatment with IFN-β. Lastly, we show that the expression of the IFN-responsive genes repressed by ETV7 could have prognostic value in breast cancer, as low expression of these genes was associated with a worse prognosis. Therefore, we propose a novel role for ETV7 in breast cancer stem cells’ plasticity and associated resistance to conventional chemotherapy and radiotherapy, which involves the repression of a group of IFN-responsive genes, potentially reversible upon IFN-β treatment. We, therefore, suggest that an in-depth investigation of this mechanism could lead to novel breast CSCs targeted therapies and to the improvement of combinatorial regimens, possibly involving the therapeutic use of IFN-β, with the aim of avoiding resistance development and relapse in breast cancer.

Improving Model Performance on the Stratification of Breast Cancer Patients by Integrating Multiscale Genomic Features

In clinical cancer research, it is a hot topic on how to accurately stratify patients based on genomic data. With the development of next-generation sequencing technology, more and more types of genomic features, such as mRNA expression level, can be used to distinguish cancer patients. Previous studies commonly stratified patients by using a single type of genomic features, which can only reflect one aspect of the cancer. In fact, multiscale genomic features will provide more information and may be helpful for clinical prediction. In addition, most of the conventional machine learning algorithms use a handcrafted gene set as features to construct models, which is generally selected by a statistical method with an arbitrary cut-off, e.g., p value < 0.05. The genes in the gene set are not necessarily related to the cancer and will make the model unreliable. Therefore, in our study, we thoroughly investigated the performance of different machine learning methods on stratifying breast cancer patients with a single type of genomic features. Then, we proposed a strategy, which can take into account the degree of correlation between genes and cancer patients, to identify the features from mRNAs and microRNAs, and evaluated the performance of the models with the new combined features of the multiscale genomic features. The results showed that, compared with the models constructed with a single type of features, the models with the multiscale genomic features generated by our proposed method achieved better performance on stratifying the ER status of breast cancer patients. Moreover, we found that the identified multiscale genomic features were closely related to the cancer by gene set enrichment analysis, indicating that our proposed strategy can well reflect the biological relevance of the genes to breast cancer. In conclusion, modelling with multiscale genomic features closely related to the cancer not only can guarantee the prediction performance of the models but also can effectively provide candidate genes for interpreting the mechanisms of cancer.

Population-based validation of the National Cancer Comprehensive Network recommendations for breast cancer staging

OBJECTIVE

The aim of the current study is to evaluate the performance characteristics of the National Comprehensive Cancer Network (NCCN) staging recommendations for breast cancer with regard to the detection of lung, bone, and liver metastases.

METHODS

Surveillance, epidemiology, and end points (SEER) database (2010-2015) was accessed, and patients with breast cancer and complete information about T stage and clinical N stage, ER status, Her2 status, and metastatic sites were extracted. Performance characteristics evaluated for the current study included sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), number needed to investigate (NNI), and accuracy.

RESULTS

A total of 239,196 patients were included in the analysis. For the overall cohort, the required PPV (for the recognition of lung metastases) is 10.6% and NNI to detect one case of lung metastasis is 9.4. Likewise, PPV (for the recognition of bone metastases) is 18.6% and NNI to detect one case of bone metastasis is 5.3. Moreover, PPV (for the recognition of liver metastases) is 7.6% and NNI to detect one case of liver metastasis is 13.1. When changing the threshold for baseline imaging to includeT2N1 patients, a better balance between sensitivity and specificity among ER+/Her2- patients (> 92% for both sensitivity and specificity for the three metastatic sites) was observed. On the other hand, the proposed change improved sensitivity while it lowers significantly the specificity among Her2+ and triple negative subtypes (specificity < 84% for Her2+ disease for the three metastatic sites; specificity < 87% for triple negative disease for the three metastatic sites).

CONCLUSION

The current NCCN recommendations for breast cancer staging have an excellent NPV and miss only few patients with lung, liver, or bone metastases. Future studies incorporating the subtype of breast cancer as a determinant of staging pathway is needed.

Rapid micro fluorescence in situ hybridization in tissue sections

This paper describes a micro fluorescence in situ hybridization (μFISH)-based rapid detection of cytogenetic biomarkers on formalin-fixed paraffin embedded (FFPE) tissue sections. We demonstrated this method in the context of detecting human epidermal growth factor 2 (HER2) in breast tissue sections. This method uses a non-contact microfluidic scanning probe (MFP), which localizes FISH probes at the micrometer length-scale to selected cells of the tissue section. The scanning ability of the MFP allows for a versatile implementation of FISH on tissue sections. We demonstrated the use of oligonucleotide FISH probes in ethylene carbonate-based buffer enabling rapid hybridization within <1 min for chromosome enumeration and 10-15 min for assessment of the HER2 status in FFPE sections. We further demonstrated recycling of FISH probes for multiple sequential tests using a defined volume of probes by forming hierarchical hydrodynamic flow confinements. This microscale method is compatible with the standard FISH protocols and with the Instant Quality FISH assay and reduces the FISH probe consumption ∼100-fold and the hybridization time 4-fold, resulting in an assay turnaround time of <3 h. We believe that rapid μFISH has the potential of being used in pathology workflows as a standalone method or in combination with other molecular methods for diagnostic and prognostic analysis of FFPE sections.

Differential prognostic impact of interleukin-34 mRNA expression and infiltrating immune cell composition in intrinsic breast cancer subtypes

Interleukin-34 (IL-34) is a ligand for the CSF-1R and has also two additional receptors, PTPRZ1 and syndecan-1. IL-34 plays a role in innate immunity, inflammation, and cancer. However, the role of IL-34 in breast cancer is still ill-defined. We analyzed IL-34 mRNA expression in breast cancer cell lines and breast cancer patients and applied established computational approaches (CIBERSORT, ESTIMATE, TIMER, TCIA), to analyze gene expression data from The Cancer Genome Atlas (TCGA). Expression of IL-34 was associated with a favorable prognosis in luminal and HER2 but not basal breast cancer patients. Gene expression of CSF-1 and CSF-1R was strongly associated with myeloid cell infiltration, while we found no or only weak correlations between IL-34, PTPRZ1, syndecan-1 and myeloid cells. In vitro experiments showed that tyrosine phosphorylation of CSF-1R, ERK, and FAK and cell migration are differentially regulated by IL-34 and CSF-1 in breast cancer cell lines. Collectively, our data suggest that correlation of IL-34 gene expression with survival is dependent on the molecular breast cancer subtype. Furthermore, IL-34 is not associated with myeloid cell infiltration and directly regulates breast cancer cell migration and signaling.

CPSF6 is a Clinically Relevant Breast Cancer Vulnerability Target: Role of CPSF6 in Breast Cancer

Breast cancer represents a major health challenge. The majority of breast cancer deaths are due to cancer progression/recurrence for which no efficient therapies exist. Aggressive breast cancers are characterized by loss of cellular differentiation. Defining molecular mechanisms/targets contributing to cancer aggressiveness is needed to guide the design of new screening and targeted treatments. Here, we describe a novel tumor promoting function for the Cleavage and Polyadenylation Factor-6 (CPSF6). Importantly, aggressive breast cancer cells of luminal B, HER2-overexpressing and triple negative subtypes show dependency on CPSF6 for viability and tumorigenic capacity. Mechanistically, we found CPSF6 to interact with components of the A-to-I RNA editing machinery, paraspeckles and ADAR1 enzyme, and to be required for their physical integrity. Clinically, we found CPSF6 and all core paraspeckles proteins to be overexpressed in human breast cancer cases and their expression to correlate with poor patient outcomes. Finally, we found prolactin, a key mammary differentiation factor, to suppress CPSF6/RNA editing activity. Together, this study revealed CPSF6 as a molecular target with clinical relevance for prognosis and therapy in breast cancer.

Precision medicine in breast cancer: reality or utopia?

Many cancers, including breast cancer, have demonstrated prognosis and support advantages thanks to the discovery of targeted therapies. The advent of these new approaches marked the rise of precision medicine, which leads to improve the diagnosis, prognosis and treatment of cancer. Precision medicine takes into account the molecular and biological specificities of the patient and their tumors that will influence the treatment determined by physicians. This new era of medicine is accessible through molecular genetics platforms, the development of high-speed sequencers and means of analysis of these data. Despite the spectacular results in the treatment of cancers including breast cancer, described in this review, not all patients however can benefit from this new strategy. This seems to be related to the many genetic mutations, which may be different from one patient to another or within the same patient. It comes to give new impetus to the research—both from a technological and biological point of view—to make the hope of precision medicine accessible to all.

Role of estrogen receptors and Src signaling in mechanisms of bone metastasis by estrogen receptor positive breast cancers

BACKGROUND/AIM

Evidence shows that Luminal A breast cancer is likely to undergo bone metastasis, but the mechanisms involved remain unknown. This study's aim was to demonstrate a correlation between estrogen receptor (ER) positivity and bone metastasis as the clinically preferred site of metastasis, as well as investigating the role of ERα-Src signaling in MCF-7 cells using Snail over-expression as an in vivo bone metastasis model.

METHODS

Clinically, the records of breast cancer with distant metastasis were retrospectively reviewed to correlate breast cancer subtypes and preferential metastatic sites. An in vivo bone metastasis model was created by injection of MCF-7 cells with/without Snail over-expression into the tibia of nude mice. The human MCF-7 cells that over-expressed (o/e) Snail were examined and the expression of epithelial-mesenchymal transitions (EMT) markers, ER-Src signaling proteins and p190 RhoGAP analyzed by Western blotting and real-time PCR. The role of ERα was elucidated using ESR1 silence by transfecting shRNA (∆ESR1) into MCF-7 o/e Snail cells in vitro and in vivo.

RESULTS

The clinical results showed that ER ≥1% breast cancers showed a positive correlation with bone metastasis, which was found to be the preferred site of metastasis. An in vivo bone metastasis was successfully established using injection of MCF-7 o/e Snail cells into the tibia of nude mice, but no such metastasis was found using control MCF-7 cells. The proteins expressed in MCF-7 o/e Snail cells showed an EMT pattern, while those of the MCF-7 o/e Snail metastatic tissue showed a mesenchymal-epithelial pattern. There was an increase in cytosolic Src, p190 RhoGAP and nuclear ERα proteins, but not in Snail, in MCF-7 o/e Snail tissue compared to the same cell line in vitro. ESR1 knock down decreased Src and p190 RhoGAP expression in vitro and also decreased the incidence of bone metastasis in vivo.

CONCLUSION

We conclude that ER-Src signaling plays an important role in ER (+) breast cancer, which shows a high potential for bone metastasis.

Low-Dose Bisphenol A Exposure: A Seemingly Instigating Carcinogenic Effect on Breast Cancer

Breast cancer is the fifth most common cause of cancer death in the world and the second most common fatal cancer in women. Epidemiological studies and clinical data have indicated that hormones, including estrogen, progesterone, and prolactin, play important roles in the initiation and progression of breast cancer. Bisphenol A (BPA) is one of the most commonly used and thoroughly studied endocrine disruptors. It can be released from consumer products and deposited in the environment, thus creating potential for human exposure through oral, inhaled, and dermal routes. Some recent reviews have summarized the known mechanisms of endocrine disruptions by BPA in human diseases, including obesity, reproductive disorders, and birth defects. However, large knowledge gaps still exist on the roles BPA may play in cancer initiation and development. Evidence from animal and in vitro studies has suggested an association between increased incidence of breast cancer and BPA exposure at doses below the safe reference doses that are the most environmentally relevant. Most current studies have paid little attention to the cancer-promoting properties of BPA at low doses. In this review, recent findings on the carcinogenic effects of low-dose BPA on breast cancer and discussed possible biologic mechanisms are summarized.

S100A8/A9 is associated with estrogen receptor loss in breast cancer

S100A8 and S100A9 are calcium-binding proteins that are secreted primarily by granulocytes and monocytes, and are upregulated during the inflammatory response. S100A8 and S100A9 have been identified to be expressed by epithelial cells involved in malignancy. In the present study, the transcriptional levels of S100A8 and S100A9 were investigated in various subtypes of breast cancer (BC), and the correlation with estrogen receptor 1 (ESR1) and GATA binding protein 3 (GATA3) gene expression was evaluated using microarray datasets. The expression of S100A8 and S100A9 in BC cells was assessed by reverse transcription-polymerase chain reaction (RT-PCR). The regulation of ESR1 and GATA3 by administration of recombinant S100A8/A9 was examined in the BC MCF-7 cell line using quantitative (q)PCR. The association between S100A8 and S100A9 and overall survival (OS) was investigated in GeneChip® data of BC. The expression levels of S100A8 and S100A9 were higher in human epidermal growth factor receptor 2 (Her2)-amplified and basal-like BC. The messenger (m)RNA levels of S100A8 and S100A9 were inversely correlated with ESR1 and GATA3 expression. S100A8/A9 induced a 10-fold decrease in the mRNA levels of ESR1 in MCF-7 cells. Poor OS was associated with high expression levels of S100A9, but not with high expression levels of S100A8 in BC. In conclusion, strong expression and secretion of S100A8/A9 may be associated with the loss of estrogen receptor in BC, and may be involved in the poor prognosis of Her2+/basal-like subtypes of BC.

Progesterone and Overlooked Endocrine Pathways in Breast Cancer Pathogenesis

Worldwide, breast cancer incidence has been increasing for decades. Exposure to reproductive hormones, as occurs with recurrent menstrual cycles, affects breast cancer risk, and can promote disease progression. Exogenous hormones and endocrine disruptors have also been implicated in increasing breast cancer incidence. Numerous in vitro studies with hormone-receptor-positive cell lines have provided insights into the complexities of hormone receptor signaling at the molecular level; in vivo additional layers of complexity add on to this. The combined use of mouse genetics and tissue recombination techniques has made it possible to disentangle hormone action in vivo and revealed that estrogens, progesterone, and prolactin orchestrate distinct developmental stages of mammary gland development. The 2 ovarian steroids that fluctuate during menstrual cycles act on a subset of mammary epithelial cells, the hormone-receptor-positive sensor cells, which translate and amplify the incoming systemic signals into local, paracrine stimuli. Progesterone has emerged as a major regulator of cell proliferation and stem cell activation in the adult mammary gland. Two progesterone receptor targets, receptor activator of NfκB ligand and Wnt4, serve as downstream paracrine mediators of progesterone receptor-induced cell proliferation and stem cell activation, respectively. Some of the findings in the mouse have been validated in human ex vivo models and by next-generation whole-transcriptome sequencing on healthy donors staged for their menstrual cycles. The implications of these insights into the basic control mechanisms of mammary gland development for breast carcinogenesis and the possible role of endocrine disruptors, in particular bisphenol A in this context, will be discussed below.

Breast Cancer: Conventional Diagnosis and Treatment Modalities and Recent Patents and Technologies

Breast cancer is the most prevalent cancer among women worldwide. However, increased survival is due to the dramatic advances in the screening methods, early diagnosis, and breakthroughs in treatments. Over the course of the last decade, many acquisitions have taken place in this critical field of research in the pharmaceutical industry. Advances in molecular biology and pharmacology aided in better understanding of breast cancer, enabling the design of smarter therapeutics able to target cancer and respond to its microenvironment efficiently. Patents and research papers investigating diagnosis and treatment strategies for breast cancer using novel technologies have been surveyed for the past 15 years. Various nanocarriers have been introduced to improve the therapeutic efficacy of anticancer drugs, including liposomes, polymeric micelles, quantum dots, nanoparticles, and dendrimers. This review provides an overview of breast cancer, conventional therapy, novel technologies in the management of breast cancer, and rational approaches for targeting breast cancer.

HIGHLIGHTS

Breast cancer is the most common cancer in women worldwide. However, survival rates vary widely, optimistically heading toward a positive trend. Increased survival is due to the drastic shift in the screening methods, early diagnosis, and breakthroughs in treatments.Different strategies of breast cancer classification and staging have evolved over the years. Intrinsic (molecular) subtyping is essential in clinical trials and well understanding of the disease.Many novel technologies are being developed to detect distant metastases and recurrent disease as well as to assess response to breast cancer management.Intensive research efforts are actively ongoing to take novel breast cancer therapeutics to potential clinical application.Most of the recent research papers and patents discuss one of the following strategies: the development of new drug entities that specifically target the breast tumor cells; tailor designing a novel carrier system that can multitask and multifunction as a drug carrier, targeting vehicle and even as a diagnostic tool, direct conjugation of a therapeutic drug moiety with a targeting moiety, diagnostic moiety or pharmacokinetics altering moiety; or the use of innovative nontraditional approaches such as genetic engineering, stem cells, or vaccinations.

Designing and Testing of Novel Taxanes to Probe the Highly Complex Mechanisms by Which Taxanes Bind to Microtubules and Cause Cytotoxicity to Cancer Cells

Our previous work identified an intermediate binding site for taxanes in the microtubule nanopore. The goal of this study was to test derivatives of paclitaxel designed to bind to this intermediate site differentially depending on the isotype of β-tubulin. Since β-tubulin isotypes have tissue-dependent expression--specifically, the βIII isotype is very abundant in aggressive tumors and much less common in normal tissues--this is expected to lead to tubulin targeted drugs that are more efficacious and have less side effects. Seven derivatives of paclitaxel were designed and four of these were amenable for synthesis in sufficient purity and yield for further testing in breast cancer model cell lines. None of the derivatives studied were superior to currently used taxanes, however computer simulations provided insights into the activity of the derivatives. Our results suggest that neither binding to the intermediate binding site nor the final binding site is sufficient to explain the activities of the derivative taxanes studied. These findings highlight the need to iteratively improve on the design of taxanes based on their activity in model systems. Knowledge gained on the ability of the engineered drugs to bind to targets and bring about activity in a predictable manner is a step towards personalizing therapies.