Basal-like breast cancer: update on clinicopathologic, immunohistochemical, and molecular features

Bcl-2 Up-Regulation Mediates Taxane Resistance Downstream of APC Loss

Triple-negative breast cancer (TNBC) patients are treated with traditional chemotherapy, such as the taxane class of drugs. One such drug, paclitaxel (PTX), can be effective in treating TNBC; however, many tumors will develop drug resistance, which can lead to recurrence. In order to improve patient outcomes and survival, there lies a critical need to understand the mechanism behind drug resistance. Our lab made the novel observation that decreased expression of the Adenomatous Polyposis Coli (APC) tumor suppressor using shRNA caused PTX resistance in the human TNBC cell line MDA-MB-157. In cells lacking APC, induction of apoptosis by PTX was decreased, which was measured through cleaved caspase 3 and annexin/PI staining. The current study demonstrates that CRISPR-mediated APC knockout in two other TNBC lines, MDA-MB-231 and SUM159, leads to PTX resistance. In addition, the cellular consequences and molecular mechanisms behind APC-mediated PTX response have been investigated through analysis of the BCL-2 family of proteins. We found a significant increase in the tumor-initiating cell population and increased expression of the pro-survival family member Bcl-2, which is widely known for its oncogenic behavior. ABT-199 (Venetoclax), is a BH3 mimetic that specifically targets Bcl-2. ABT-199 has been used as a single or combination therapy in multiple hematologic malignancies and has shown promise in multiple subtypes of breast cancer. To address the hypothesis that APC-induced Bcl-2 increase is responsible for PTX resistance, we combined treatment of PTX and ABT-199. This combination treatment of CRISPR-mediated APC knockout MDA-MB-231 cells resulted in alterations in apoptosis, suggesting that Bcl-2 inhibition restores PTX sensitivity in APC knockout breast cancer cells. Our studies are the first to show that Bcl-2 functional inhibition restores PTX sensitivity in APC mutant breast cancer cells. These studies are critical to advance better treatment regimens in patients with TNBC.

Identification of the new molecular subtypes related to inflammation in breast cancer

Breast cancer is a prevalent ailment among women, and the inflammatory response plays a crucial role in the management and prediction of breast cancer (BRCA). However, the new subtypes based on inflammation in BRCA research are still undefined. The databases including The Cancer Genome Atlas and gene expression omnibus were utilized to gather clinical data and somatic mutation information for approximately 1069 BRCA patients. Through Consensus Clustering, novel subtypes linked to inflammation were identified. A comparative analysis was conducted on the prognosis, and immune cell infiltration, and somatic mutation of the new subtypes. Additionally, an investigation into drug therapy and immunotherapy was conducted to distinguish high-risk individuals from low-risk ones. The findings of this investigation proposed the categorization of BRCA into innovative subtypes predicated on the inflammatory response and 6 key genes were a meaningful approach. Specifically, the low-, medium-, and high-inflammation subtypes exhibited varying degrees of association with clinicopathological features, tumor microenvironment, and prognosis. Notably, the high-inflammation subtype was characterized by a strong correlation with immunosuppressive microenvironments and a higher frequency of somatic mutations, which was an indication of poorer health. This study revealed that a brand-new classification could throw new light on the effective prognosis. The integration of multiple key genes was a new characterization that could promote more immunotherapy strategies and contribute to predicting the efficacy of the chemotherapeutic drugs.

HDAC11: A novel target for improved cancer therapy

Histone deacetylase 11 (HDAC11) is a unique member of the histone deacetylase family that plays an important role in the regulation of gene expression and protein function. In recent years, research on the role of HDAC11 in tumors has attracted increasing attention. This review summarizes the current knowledge on the subcellular localization, structure, expression, and functions of HDAC11 in tumors, as well as the regulatory mechanisms involved in its network, including ncRNA and substrates. Moreover, we focus on the progress made in targeting HDAC11 to overcome tumor therapy resistance, and the development of HDAC11 inhibitors for cancer treatment. Collectively, this review provides comprehensive insights into the potential clinical implications of HDAC11 for cancer therapy.

Delineating intra-tumoral heterogeneity and tumor evolution in breast cancer using precision-based approaches

The burden of breast cancer continues to increase worldwide as it remains the most diagnosed tumor in females and the second leading cause of cancer-related deaths. Breast cancer is a heterogeneous disease characterized by different subtypes which are driven by aberrations in key genes such as BRCA1 and BRCA2, and hormone receptors. However, even within each subtype, heterogeneity that is driven by underlying evolutionary mechanisms is suggested to underlie poor response to therapy, variance in disease progression, recurrence, and relapse. Intratumoral heterogeneity highlights that the evolvability of tumor cells depends on interactions with cells of the tumor microenvironment. The complexity of the tumor microenvironment is being unraveled by recent advances in screening technologies such as high throughput sequencing; however, there remain challenges that impede the practical use of these approaches, considering the underlying biology of the tumor microenvironment and the impact of selective pressures on the evolvability of tumor cells. In this review, we will highlight the advances made thus far in defining the molecular heterogeneity in breast cancer and the implications thereof in diagnosis, the design and application of targeted therapies for improved clinical outcomes. We describe the different precision-based approaches to diagnosis and treatment and their prospects. We further propose that effective cancer diagnosis and treatment are dependent on unpacking the tumor microenvironment and its role in driving intratumoral heterogeneity. Underwriting such heterogeneity are Darwinian concepts of natural selection that we suggest need to be taken into account to ensure evolutionarily informed therapeutic decisions.

Comparative analysis of clinicopathological characteristics of central necrotizing breast cancer and basal cell-like breast cancer

Purpose

This study aims to compare the clinicopathological and immunohistochemical characteristics of centrally necrotizing carcinoma of the breast (CNC) and basal-like breast cancer (BLBC), as well as to analyze the characteristics of the molecular typing of the CNC.

Methods

The clinicopathological features of 69 cases of CNC and 48 cases of BLBC were observed and compared. EnVision immunohistochemical staining was performed to detect the expressions of hypoxia-inducible factor 1α (HIF-1α), breast cancer susceptibility gene 1 (BRCA1), and vascular endothelial growth factor (VEGF) in CNC and BLBC.

Results

The age of the 69 patients ranged from 32 to 80 years, with an average of 54.55 years. Gross examination showed that most tumors were well-defined single central nodules with a diameter of 1.2~5.0 cm. Microscopically, there is a large necrotic or acellular area in the center of the tumor, mainly composed of tumor coagulative necrosis with varying degrees of fibrosis or hyaline degeneration. A small amount of cancer tissue remained in the form of a ribbon or small nest around the necrotic focus. Among 69 cases of CNC, the proportion of basal cell type (56.5%) was significantly higher than that of lumen type A (18.84%), lumen type B (13.04%), HER2 overexpression (5.8%), and nonexpression (5.8%). A total of 31 cases were followed up for 8~50 months, with an average of 33.94 months. There have been nine cases of disease progression. When compared to BLBC, there were no significant differences in BRCA1 and VEGF protein expression in response to CNC (p > 0.05), but there were significant differences in protein expression in HIF-1α (p < 0.05).

Conclusion

The molecular typing of CNC showed that over half of those were BLBC. No statistically significant difference in the expression of BRCA1 was observed between CNC and BLBC; thus, we predict that targeted therapy for BRCA1 in BLBC may also have considerable effects in CNC patients. The expression of HIF-1α is significantly different in CNC and BLBC, and perhaps HIF-1α can be used as a new entry point to distinguish between the two. There is a significant correlation between the expression of VEGF and HIF-1α in BLBC, and there was no significant correlation between the expression levels of the two proteins in CNC.

Isopimaric acid, an ion channel regulator, regulates calcium and oxidative phosphorylation pathways to inhibit breast cancer proliferation and metastasis

Breast cancer is the globally most common malignant tumor and the biggest threat to women. Even though the diagnosis and treatment of breast cancer are progressing continually, a large number of breast cancer patients eventually develop a metastatic tumor, especially triple-negative breast cancer (TNBC). Recently, metal ion homeostasis and ion signaling pathway have become important targets for cancer therapy. In this study, We analyzed the effects and mechanisms of isopimaric acid (IPA), an ion channel regulator, on the proliferation and metastasis of breast cancer cells (4 T1, MDA-MB-231and MCF-7) by cell functional assay, flow cytometry, western blot, proteomics and other techniques in vitro and in vivo. Results found that IPA significantly inhibited the proliferation and metastasis of breast cancer cells (especially 4 T1). Further studies on the anti-tumor mechanism of IPA suggested that IPA might affect EMT and Wnt signaling pathways by targeting mitochondria oxidative phosphorylation and Ca²⁺ signaling pathways, and then inducing breast cancer cell cycle arrest and apoptosis. Our research reveals the therapeutic value of IPA in breast cancer and provides a theoretical basis for the new treatment of breast cancer.

Proteins Found in the Triple-Negative Breast Cancer Secretome and Their Therapeutic Potential

The cancer secretome comprises factors secreted by tumors, including cytokines, growth factors, proteins from the extracellular matrix (ECM), proteases and protease inhibitors, membrane and extracellular vesicle proteins, peptide hormones, and metabolic proteins. Secreted proteins provide an avenue for communication with other tumor cells and stromal cells, and these in turn promote tumor growth and progression. Breast cancer is the most commonly diagnosed cancer in women in the US and worldwide. Triple-negative breast cancer (TNBC) is characterized by its aggressiveness and its lack of expression of the estrogen receptor (ER), progesterone receptor (PR), and HER2, making it unable to be treated with therapies targeting these protein markers, and leaving patients to rely on standard chemotherapy. In order to develop more effective therapies against TNBC, researchers are searching for targetable molecules specific to TNBC. Proteins in the TNBC secretome are involved in wide-ranging cancer-promoting processes, including tumor growth, angiogenesis, inflammation, the EMT, drug resistance, invasion, and development of the premetastatic niche. In this review, we catalog the currently known proteins in the secretome of TNBC tumors and correlate these secreted molecules with potential therapeutic opportunities to facilitate translational research.

Aberrant promoter methylation contributes to LRIG1 silencing in basal/triple-negative breast cancer

BACKGROUND

LRIG1, the founding member of the LRIG (leucine-rich repeat and immunoglobulin-like domain) family of transmembrane proteins, is a negative regulator of receptor tyrosine kinases and a tumour suppressor. Decreased LRIG1 expression is consistently observed in cancer, across diverse tumour types, and is linked to poor patient prognosis. However, mechanisms by which LRIG1 is repressed are not fully understood. Silencing of LRIG1 through promoter CpG island methylation has been reported in colorectal and cervical cancer but studies in breast cancer remain limited.

METHODS

In silico analysis of human breast cancer patient data were used to demonstrate a correlation between DNA methylation and LRIG1 silencing in basal/triple-negative breast cancer, and its impact on patient survival. LRIG1 gene expression, protein abundance, and methylation enrichment were examined by quantitative reverse-transcription PCR, immunoblotting, and methylation immunoprecipitation, respectively, in breast cancer cell lines in vitro. We examined the impact of global demethylation on LRIG1 expression and methylation enrichment using 5-aza-2'-deoxycytidine. We also examined the effects of targeted demethylation of the LRIG1 CpG island, and transcriptional activation of LRIG1 expression, using the RNA guided deadCas9 transactivation system.

RESULTS

Across breast cancer subtypes, LRIG1 expression is lowest in the basal/triple-negative subtype so we investigated whether differential methylation may contribute to this. Indeed, we find that LRIG1 CpG island methylation is most prominent in basal/triple-negative cell lines and patient samples. Use of the global demethylating agent 5-aza-2'-deoxycytidine decreases methylation leading to increased LRIG1 transcript expression in basal/triple-negative cell lines, while having no effect on LRIG1 expression in luminal/ER-positive cell lines. Using a CRISPR/deadCas9 (dCas9)-based targeting approach, we demonstrate that TET1-mediated demethylation (Tet1-dCas9) along with VP64-mediated transcriptional activation (VP64-dCas9) at the CpG island, increased endogenous LRIG1 expression in basal/triple-negative breast cancer cells, without transcriptional upregulation at predicted off-target sites. Activation of LRIG1 by the dCas9 transactivation system significantly increased LRIG1 protein abundance, reduced site-specific methylation, and reduced cancer cell viability. Our findings suggest that CRISPR-mediated targeted activation may be a feasible way to restore LRIG1 expression in cancer.

CONCLUSIONS

Our study contributes novel insight into mechanisms which repress LRIG1 in triple-negative breast cancer and demonstrates for the first time that targeted de-repression of LRIG1 in cancer cells is possible. Understanding the epigenetic mechanisms associated with repression of tumour suppressor genes holds potential for the advancement of therapeutic approaches.

Preoperative Rim Enhancement on Magnetic Resonance Imaging Indicates Larger Tumor Size and Poor Prognosis in Chinese Basal-Like Breast Cancer Patients

Background: This study was to investigate the prevalence of preoperative rim enhancement, and its association with clinicopathological features, relapse, and survival profiles in Chinese basal-like breast cancer (BC) patients. Materials and Methods: The preoperative breast magnetic resonance imaging images of 145 basal-like BC patients who underwent surgical excision were obtained to determine rim enhancement. Besides, based on disease status and survival status during follow-up, the 1-year relapse rate/mortality, 3-year relapse rate/mortality, 5-year relapse rate/mortality were calculated; disease-free survival (DFS) and overall survival (OS) were determined. Results: There were 51 (35.2%) patients with rim enhancement and 94 (64.8%) patients without rim enhancement. Furthermore, rim enhancement was associated with larger tumor size and advanced T stage, whereas it did not associate with age, pathological differentiation, N stage, or TNM stage. In addition, rim enhancement was associated with higher 1-, 3-, and 5-year relapse rate and shorter DFS; meanwhile, rim enhancement was associated with increased 1-, 3-, and 5-year mortality rate and decreased OS. By multivariate Cox's regression analyses, rim enhancement, pathological differentiation, and N stage independently predicted reduced DFS; T stage independently predicted declined OS. Conclusion: Preoperative rim enhancement on MRI might be a possible noninvasive indicator for guiding personalized treatment strategies and improving prognosis in Chinese basal-like BC patients.

A clinicopathological study of triple-negative breast carcinoma in a patient cohort from a tertiary care center in Sri Lanka

Background

Triple negative breast carcinoma (TNBC) and basal-like breast carcinoma (BLBC) are subtypes of breast carcinoma (BCa) that are associated with poor survival.

Aims

To study the prevalence, clinicopathological profile and survival of TNBC among a Sri Lankan patient cohort and to determine the proportion and predictive histological features of BLBC among TNBCs.

Study Setting and Design

A cohort of 221 women undergoing primary surgery for BCa at a tertiary-care center in Sri Lanka was studied.

Materials and Methods

Clinicopathological and follow-up information were collected by patient interviews and review of slides and clinical records. Estrogen, progesterone, HER2 receptors, and basal markers (CK5/6, CK14, EGFR, 34βE12) were evaluated immunohistochemically.

Statistical Analysis

Data was analyzed with Chi-square test, multinomial logistic regression, and Cox regression using SPSS20.0.

Results

Fifty-three (24%) tumors were triple-negative (95%CI = 18.37%-29.63%). On multivariate analysis, young age (P = 0.002), high Nottingham grade (P = 0.005), moderate to severe tumor necrosis (P = 0.004), absent ductal carcinoma in situ (DCIS) (P = 0.04), reduced vascular density at tumor edge (P = 0.016) and distinct cell margins (P = 0.047) predicted TNBC over luminal subgroups, whereas reduced vascular density (P = 0.004) and low TNM stage (P = 0.011) distinguished TNBC and HER2. BLBC accounted for 45.28% (95%CI 32.66%-58.55%-24/53) of TNBC. The presence of extensive necrosis in TNBC correlated significantly with BLBC (P = 0.03). The survival among the TNBC subgroup did not differ significantly from other subgroups.

Conclusion

Twenty four percent were TNBCs by immunohistochemical analysis, comparable to studies in the Indian subcontinent, however higher than the West. TNBC status correlated with younger age, high tumor grade, necrosis, absent DCIS, reduced vascular density at tumor edge, and distinct cell margins. The presence of moderate to extensive necrosis in TNBC was predictive of BLBC.

High frequency of p16 and SOX10 coexpression but not androgen receptor expression in triple-negative breast cancers

Triple-negative breast cancers (TNBCs) represent approximately 12-17% of all breast cancers and have distinctively aggressive clinical courses. Because routine biomarkers for breast cancer do not apply for TNBCs, it is essential to find novel prognostic markers and potential targets for therapeutic agents. p16 and SOX10 are emerging biomarkers with relatively unexplored expressions in TNBCs. We present an analysis of the expression of p16 and SOX10 in combination with that of androgen receptor (AR) and cytokeratin (CK) 5/6 in TNBCs. In addition, we used tissue microarrays (TMAs) to compare frequencies of p16 and SOX10 between TNBCs and non-TNBCs. Fifty-six TNBC samples with clinical data were stained immunohistochemically with p16, SOX10, AR, and CK5/6. Fifty-four cases (96.4%) were invasive ductal carcinoma, not otherwise specified, and 46 cases (82.1%) were Nottingham histologic grade 3. The majority of TNBC cases were positive for p16 (n = 44; 78.6%) and SOX10 (n = 48; 85.7%). AR was positive in 15 cases (26.8%). CK5/6 was positive in 24 cases (42.9%), which were classified as basal-like breast cancer (BLBC) subtype. The frequencies of p16 and SOX10 expression in BLBC and non-BLBC subtypes did not reveal significant statistical difference in a separate analysis. Using archived TNBC and non-TNBC TMAs, we observed that 56% of TNBC cases were positive for p16 compared with 16% of non-TNBC cases (p-value <0.0001). SOX10 was positive in 80% of TNBC cases compared with 35% of non-TNBC cases (p-value <0.0001). A significant correlation was observed between p16 and SOX10 coexpression in TNBC cases (n = 56/80, p = 0.02) but not in non-TNBC cases (n = 23/348; p = 0.626). In conclusion, p16 and SOX10 are frequently expressed in TNBC, regardless of CK5/6 expression. Furthermore, p16 and SOX10 are often coexpressed in TNBCs compared with non-TNBCs.

Pathology of triple negative breast cancer

Triple negative breast cancer (TNBC) is a subtype of breast tumor lacking hormone receptors expression and HER2 gene amplification and represents 24 % of newly diagnosed breast neoplasms. In this review, pathological aspects of triple-negative breast cancer are illustrated, with particular attention to the seminal studies that defined this subtype of breast cancer by a molecular point of view. This paper also focuses on practical issues raised in clinical routine by the introduction of genetic expression breast cancer profiling and the innovative prognostic and predictive impact on triple-negative breast cancer pathology. Moreover, histopathological aspects of triple-negative neoplasms are also mentioned, underlying the importance of histologic diagnosis of particular cancer subtypes with decisive impact on clinical outcome. Importantly, focus on new therapeutic frontier represented by immunotherapy is illustrated, with particular mention of immune checkpoint inhibitors introduction in TNBC therapy and their impact on future treatments.

N-glycosylated SGK196 suppresses the metastasis of basal-like breast cancer cells

SGK196 is a protein O-mannose kinase involved in an indispensable phosphorylation step during laminin-binding glycan synthesis on alpha-dystroglycan (α-DG). However, the function of SGK196 in cancer diseases remains elusive. In the current study, we demonstrated that SGK196 is primarily modified by N-glycosylation in breast cancer (BC) cells. Furthermore, gain and loss-of-function studies showed that N-glycosylated SGK196 suppresses cell migration, invasion, and metastasis in BC, particularly in the basal-like breast cancer (BLBC) type. In addition, we found that SGK196 N-glycosylation performs the regulatory function through the PI3K/AKT/GSK3β signaling pathway. Collectively, our results show that N-glycosylated SGK196 plays suppression roles in BLBC metastases, therefore providing new insights into SGK196 function in BC.

Deubiquitinase Activity Profiling Identifies UCHL1 as a Candidate Oncoprotein That Promotes TGFβ-Induced Breast Cancer Metastasis

PURPOSE

Therapies directed to specific molecular targets are still unmet for patients with triple-negative breast cancer (TNBC). Deubiquitinases (DUB) are emerging drug targets. The identification of highly active DUBs in TNBC may lead to novel therapies.

EXPERIMENTAL DESIGN

Using DUB activity probes, we profiled global DUB activities in 52 breast cancer cell lines and 52 patients' tumor tissues. To validate our findings in vivo, we employed both zebrafish and murine breast cancer xenograft models. Cellular and molecular mechanisms were elucidated using in vivo and in vitro biochemical methods. A specific inhibitor was synthesized, and its biochemical and biological functions were assessed in a range of assays. Finally, we used patient sera samples to investigate clinical correlations.

RESULTS

Two DUB activity profiling approaches identified UCHL1 as being highly active in TNBC cell lines and aggressive tumors. Functionally, UCHL1 promoted metastasis in zebrafish and murine breast cancer xenograft models. Mechanistically, UCHL1 facilitates TGFβ signaling-induced metastasis by protecting TGFβ type I receptor and SMAD2 from ubiquitination. We found that these responses are potently suppressed by the specific UCHL1 inhibitor, 6RK73. Furthermore, UCHL1 levels were significantly increased in sera of patients with TNBC, and highly enriched in sera exosomes as well as TNBC cell-conditioned media. UCHL1-enriched exosomes stimulated breast cancer migration and extravasation, suggesting that UCHL1 may act in a paracrine manner to promote tumor progression.

CONCLUSIONS

Our DUB activity profiling identified UCHL1 as a candidate oncoprotein that promotes TGFβ-induced breast cancer metastasis and may provide a potential target for TNBC treatment.

Drug Combinations in Breast Cancer Therapy

Breast cancer therapy involves a multidisciplinary approach comprising surgery, radiotherapy, neoadjuvant and adjuvant therapy. Effective therapy of breast cancer requires maximum therapeutic efficacy, with minimal undesirable effects to ensure a good quality of life for patients. The carefully selected combination of therapeutic interventions provides patients with the opportunity to derive maximum benefit from therapy while minimizing or eliminating recurrence, resistance and toxic effects, as well as ensuring that patients have a good quality of life. This review discusses therapeutic options for breast cancer treatments and various combinations that had been previously exploited. The review will also give an insight into the potential application of the nanotechnology platform for codelivery of therapeutics in breast cancer therapy.

Genomics applied to the treatment of breast cancer

Breast cancer remains a major health issue in the world with 1.7 million new cases in 2012 worldwide. It is the second cause of death from cancer in western countries. Genomics have started to modify the treatment of breast cancer, and the developments should become more and more significant, especially in the present era of treatment personalization and with the implementation of new technologies. With molecular signatures, genomics enabled a de-escalation of chemotherapy and personalized treatments of localized forms of estrogen-dependent breast cancers. Genomics can also make a real contribution to constitutional genetics, so as to identify mutations in a panel of candidate genes. In this review, we will discuss the contributions of genomics applied to the treatment of breast cancer, whether already validated contributions or possible future applications linked to research data.

Genome-wide association study of cervical cancer suggests a role for ARRDC3 gene in human papillomavirus infection

The development of cervical cancer is initiated by human papillomavirus (HPV) infection and involves both viral and host genetic factors. Genome-wide association studies (GWAS) of cervical cancer have identified associations in the HLA locus and two loci outside HLA, but the principal genes that control infection and pathogenesis have not been identified. In the present study, we performed GWAS of cervical cancer in East Asian populations, involving 2609 cases and 4712 controls in the discovery stage and 1461 cases and 3295 controls in the follow-up stage. We identified novel-significant associations at 5q14 with the lead single nucleotide polymorphism (SNP) rs59661306 (P = 2.4 × 10-11) and at 7p11 with the lead SNP rs7457728 (P = 1.2 × 10-8). In 5q14, the chromatin region of the GWAS-significant SNPs was found to be in contact with the promoter of the ARRDC3 (arrestin domain-containing 3) gene. In our functional studies, ARRDC3 knockdown in HeLa cells caused significant reductions in both cell growth and susceptibility to HPV16 pseudovirion infection, suggesting that ARRDC3 is involved in the infectious entry of HPV into the cell. Our study advances the understanding of host genes that are responsible for cervical cancer susceptibility and guides future research on HPV infection and cancer development.

The Proliferative and Apoptotic Landscape of Basal-like Breast Cancer

Basal-like breast cancer (BLBC) is an aggressive molecular subtype that represents up to 15% of breast cancers. It occurs in younger patients, and typically shows rapid development of locoregional and distant metastasis, resulting in a relatively high mortality rate. Its defining features are that it is positive for basal cytokeratins and, epidermal growth factor receptor and/or c-Kit. Problematically, it is typically negative for the estrogen receptor and human epidermal growth factor receptor 2 (HER2), which means that it is unsuitable for either hormone therapy or targeted HER2 therapy. As a result, there are few therapeutic options for BLBC, and a major priority is to define molecular subgroups of BLBC that could be targeted therapeutically. In this review, we focus on the highly proliferative and anti-apoptotic phenotype of BLBC with the goal of defining potential therapeutic avenues, which could take advantage of these aspects of tumor development.

NrF2/ARE and NF-κB pathway regulation may be the mechanism for lutein inhibition of human breast cancer cell

Aim: Though lutein can inhibit cancer cell proliferation via alleviating oxidative injury, the molecular mechanisms of lutein involvement in the NrF2/antioxidant response element (ARE) and NF-κB pathways remain poorly understood. Materials & methods: MTT, flow cytometry, quantitative real-time PCR (qRT-PCR) and western blot assays were performed. Results: After treatment with lutein, breast cancer cell proliferation was significantly decreased in a dose-dependent manner. Lutein induced nuclear translocation and protein expression of NrF2, improved the expression of cellular antioxidant enzymes and attenuated reactive oxygen species levels. Moreover, lutein treatment decreased NF-κB signaling pathway related NF-κB p65 protein expression. Conclusion: The effect of lutein antiproliferation was mediated by activation of the NrF2/ARE pathway, and blocking of the NF-κB signaling pathway.

G-protein-coupled receptor 81 promotes a malignant phenotype in breast cancer through angiogenic factor secretion

G-protein-coupled receptor 81 (GPR81) functions as a receptor for lactate and plays an important role in the regulation of anti-lipolytic effects in adipocytes. However, to data, a role for GPR81 in the tumor microenvironment has not been clearly defined. Here, GPR81 expression in breast cancer patients and several breast cancer cell lines was significantly increased compared with normal mammary tissues and cells. GPR81 knockdown resulted in impaired breast cancer growth and led to apoptosis both in vitro and in vivo. Furthermore, the inhibition of GPR81 signaling suppressed angiogenesis through a phosphoinositide 3-OH kinase (PI3K)/Akt-cAMP response element binding protein (CREB) pathway, which led to decreased production of the pro-angiogenic mediator amphiregulin (AREG). Overall, these findings identify GPR81 as a tumor-promoting receptor in breast cancer progression and suggest a novel mechanism that regulates GPR81-dependent activation of the PI3K/Akt signaling axis in tumor microenvironment.

The suppression of DUSP5 expression correlates with paclitaxel resistance and poor prognosis in basal-like breast cancer

Basal-like breast cancer (BLBC) is resistant to endocrinotherapy and targeted therapy and new molecular therapies are needed for BLBC. In this study, we evaluated the role of DUSP1 and DUSP5, negative regulators of mitogen-activated protein kinase pathway, in the aggressiveness of BLBC. MDA-MB-231 cells were given paclitaxel (PTX) treatment and subsequently PTX resistant cell clones were established. Microarray analysis, real-time quantitative reverse transcription PCR (qRT-PCR), and online analysis of large cohorts of breast cancer patients were performed. The PTX resistant cells showed stronger cell proliferation ability by exhibiting the upregulation of CENPF, CDC6, MCM3, CLSPN and SMC1A expression. Furthermore, DUSP1 and DUSP5 expression was significantly downregulated in PTX resistant cells. In addition, in large breast cancer patients' database, both DUSP1 and DUSP5 correlated negatively with higher histological grade. DUSP1 low expression was obvious in HER2 positive and basal like while DUSP5 low expression was peculiar for basal like compared with other subtypes. Remarkably, low expression of DUSP5, but not DUSP1, was significantly correlated with poor survival of BLBC patients. In conclusion, our data suggest that loss of DUSP5 expression results in PTX resistance and tumor progression, providing a rationale for a therapeutic agent that restores DUSP5 in BLBC.

Characterization of immortalized human mammary epithelial cell line HMEC 2.6

Primary human mammary epithelial cells have a limited life span which makes it difficult to study them in vitro for most purposes. To overcome this problem, we have developed a cell line that was immortalized using defined genetic elements, and we have characterized this immortalized non-tumorigenic human mammary epithelial cell line to establish it as a potential model system. human mammary epithelial cells were obtained from a healthy individual undergoing reduction mammoplasty at SIU School of Medicine. The cells were transduced with CDK4R24C followed by transduction with human telomerase reverse transcriptase. Post all manipulation, the cells displayed a normal cell cycle phase distribution and were near diploid in nature, which was confirmed by flow cytometry and karyotyping. In vitro studies showed that the cells were anchorage dependent and were non-invasive in nature. The cell line expressed basal epithelial markers such as cytokeratin 7, CD10, and p63 and was negative for the expression of estrogen receptor and progesterone receptor. Upon G-band karyotyping, the cell line displayed the presence of a few cytogenic abnormalities, including trisomy 20 and trisomy 7, which are also commonly present in other immortalized mammary cell lines. Furthermore, the benign nature of these cells was confirmed by multiple in vitro and in vivo experiments. Therefore, we think that this cell line could serve as a good model to understand the molecular mechanisms involved in the development and progression of breast cancer and to also assess the effect of novel therapeutics on human mammary epithelial cells.

Cancer-associated fibroblasts release exosomal microRNAs that dictate an aggressive phenotype in breast cancer

Cancer-associated fibroblasts (CAFs) are the major components of the tumor microenvironment. They may drive tumor progression, although the mechanisms involved are still poorly understood. Exosomes have emerged as important mediators of intercellular communication in cancer. They mediate horizontal transfer of microRNAs (miRs), mRNAs and proteins, thus affecting breast cancer progression. Differential expression profile analysis identified three miRs (miRs -21, -378e, and -143) increased in exosomes from CAFs as compared from normal fibroblasts. Immunofluorescence indicated that exosomes may be transferred from CAFs to breast cancer cells, releasing their cargo miRs. Breast cancer cells (BT549, MDA-MB-231, and T47D lines) exposed to CAF exosomes or transfected with those miRs exhibited a significant increased capacity to form mammospheres, increased stem cell and epithelial-mesenchymal transition (EMT) markers, and anchorage-independent cell growth. These effects were reverted by transfection with anti-miRs. Similarly to CAF exosomes, normal fibroblast exosomes transfected with miRs -21, -378e, and -143 promoted the stemness and EMT phenotype of breast cancer cells. Thus, we provided evidence for the first time of the role of CAF exosomes and their miRs in the induction of the stemness and EMT phenotype in different breast cancer cell lines. Indeed, CAFs strongly promote the development of an aggressive breast cancer cell phenotype.

Loss of constitutive ABCB1 expression in breast cancer associated with worse prognosis

ABCB1 gene encodes an adenosine 5′-triphosphate–binding cassette transporter, which not only confers multidrug resistance phenotype in malignant cells, but is also present in several nonmalignant tissues. For the last thirty years, ABCB1 expression in breast cancer has been described by many authors, but the extent of expression differs among the studies, and there is no consensus regarding its potential role in carcinogenesis or in the tumor response to antineoplastic drugs. This study aimed to characterize the expression of ABCB1 in breast tumors as a function of genetic, clinical, and histopathological variables. The ABCB1 expression was also evaluated in nonmalignant mammary tissues adjacent to tumors and in benign lesions. The detection of ABCB1 protein was performed by immunohistochemistry in tissue specimens of excised breasts obtained from a prospective cohort of Brazilian women with breast cancer. The association of ABCB1 protein levels with ABCB1 mRNA, gene polymorphisms, and clinical and histopathological variables was also evaluated. The Kaplan–Meier curves and multivariate Cox regression analyses were conducted to identify independent predictors of disease-free survival of patients with breast cancer. ABCB1 was detected in 86.3% (656) of breast tumors, 98.8% (606) of nonmalignant mammary tissue adjacent to tumors, and 100% (28) of benign lesions. Reduced ABCB1 protein levels in breast tumors was associated with triple-negative subtype (adjusted odds ratio [OR_adj] =0.24; 95% confidence interval [CI] =0.13–0.45), lymph node status < pN2 (OR_adj =0.27; 95% CI =0.10–0.71), tumor size >2 cm (OR_adj =0.55; 95% CI =0.32–0.93), and hypertensive status (OR_adj =0.42; 95% CI =0.24–0.73), and it was significantly associated with shorter disease-free survival, either for all breast cancer patients (p log-rank =0.012; hazard ratio [HR] =3.46; 95% CI =1.21–9.91) or for those with triple-negative tumors (p log-rank =0.007; HR =11.41; 95% CI =1.29–100.67). The loss of constitutive ABCB1 expression in breast cancer, especially in triple-negative tumors, seems to indicate a subgroup of worse prognosis.

Cytokeratin 5/6 expression, prognosis, and association with estrogen receptor α in high-grade serous ovarian carcinoma

High-grade serous ovarian carcinoma remains one of the most lethal malignancies in women. For histopathologic differentiation from mesothelioma cytokeratin, 5/6 immunohistochemistry is widely used. Another preferred marker for differential diagnosis to mesothelioma is estrogen receptor α (ER-α). In this study, we determined the rate of cytokeratin 5/6-positive cells in primary high-grade serous carcinoma. A cohort of 215 patients with high-grade serous ovarian carcinoma was evaluated immunohistochemically for the protein expression of cytokeratin 5/6. Most tumors demonstrated at least partly positive for cytokeratin 5/6 (n=148; 68.3%), showing different staining patterns from scattered stained cells to a diffuse staining, at times with a distinctive tumor-stroma border motif. Sixty-seven (31%) were entirely negative. No correlation of cytokeratin immunoreactivity score (IRS) with conventional staging parameters could be demonstrated. From the different IRS values for cytokeratin 5/6, IRS=12 (n=6; 2.9%) seemed to indicate a worse prognosis, albeit not statistically significant. An association with ER-α expression could not be detected but the combination of cytokeratin 5/6 IRS=12 and ER-α negativity resulted in a significant negative prognostic marker (overall survival: P=.003 and progression-free survival: P<.0001). We substantiate cytokeratin 5/6 protein expression as a frequent feature of high-grade serous ovarian carcinoma with various staining patterns, an important fact for the routine differential diagnosis with mesothelioma. Furthermore, cytokeratin 5/6 in combination with ER-α proved to be a negative prognostic marker, wherefore we suggest further investigation of its biological significance and possible manifestation of a basal differentiation.

Cell-specific biomarkers and targeted biopharmaceuticals for breast cancer treatment

Breast cancer is the second leading cause of cancer death among women, and its related treatment has been attracting significant attention over the past decades. Among the various treatments, targeted therapy has shown great promise as a precision treatment, by binding to cancer cell-specific biomarkers. So far, great achievements have been made in targeted therapy of breast cancer. In this review, we first discuss cell-specific biomarkers, which are not only useful for classification of breast cancer subtyping but also can be utilized as goals for targeted therapy. Then, the innovative and generic-targeted biopharmaceuticals for breast cancer, including monoclonal antibodies, non-antibody proteins and small molecule drugs, are reviewed. Finally, we provide our outlook on future developments of biopharmaceuticals, and provide solutions to problems in this field.

Immunohistochemical Subtypes of Breast Cancer: Correlation with Clinicopathological and Radiological Factors

BACKGROUND

The relationship between biomarkers and imaging features is important because imaging findings can predict molecular features.

OBJECTIVES

To investigate the relationship between clinicopathologic and radiologic factors and the immunohistochemical (IHC) profiles associated with breast cancer.

PATIENTS AND METHODS

From December 2004 to September 2013, 200 patients (mean age, 56 years; range, 29 - 82 years) were diagnosed with breast cancer and underwent surgery at our institution. Their medical records were reviewed to determine age, symptom presence, mammographic findings (including mass, asymmetry, microcalcifications, or negativity), sonographic Breast Imaging-Reporting and Data System (BI-RADS) category, pathologic type of cancer (invasive ductal, mucinous, medullary, or papillary carcinoma), histologic grade, T-stage, and IHC subtypes. Based on the IHC profiles, tumor subtypes were classified as luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) enriched, or triple-negative (TN) cancers. Using univariate and multivariate logistic regression analyses, we looked for correlations between four IHC subtypes and two IHC subtypes (TN and non-triple negative [non-TN]) and clinicopathologic and radiologic factors, respectively.

RESULTS

Based on our univariate analyses with the four subtypes, the TN subtype showed a higher incidence of masses on mammography compared to the other subtypes (P = 0.037), and the TN subtype also tended to have the highest histologic grade among the subtypes (P < 0.001). With regard to the two IHC subtypes, the TN subtype had a significant association with medullary cancer (P = 0.021), higher histologic grade (grade 3; P < 0.001), and higher T stage (T2; P = 0.027) compared to the non-TN subtypes. In a multivariate logistic regression analysis of the clinicoradiologic factors compared to luminal A, the HER2 subtype had a significant association with BI-RADS category 4b (odds ratio [OR], 9.005; 95% confidence interval [CI], 1.414 - 57.348; P = 0.020) and borderline significance with category 4c (OR, 4.669; 95% CI, 0.970 - 22.468; P = 0.055). In a multivariate logistic regression analysis of the clinicoradiologic factors associated with the non-TN subtypes, the TN subtype was significantly correlated with medullary carcinoma (OR, 7.092; 95% CI, 1.149 - 43.772; P = 0.035).

CONCLUSION

These results suggest that patients with the TN subtypes are more likely to have higher-histologic-grade tumors and medullary cancer. The HER2 subtype was typically associated with a higher BI-RADS category.

Targeting lactate transport suppresses in vivo breast tumour growth

BACKGROUND

Most cancers, including breast cancer, have high rates of glucose consumption, associated with lactate production, a process referred as "Warburg effect". Acidification of the tumour microenvironment by lactate extrusion, performed by lactate transporters (MCTs), is associated with higher cell proliferation, migration, invasion, angiogenesis and increased cell survival. Previously, we have described MCT1 up-regulation in breast carcinoma samples and demonstrated the importance of in vitro MCT inhibition. In this study, we performed siRNA knockdown of MCT1 and MCT4 in basal-like breast cancer cells in both normoxia and hypoxia conditions to validate the potential of lactate transport inhibition in breast cancer treatment.

RESULTS

The effect of MCT knockdown was evaluated on lactate efflux, proliferation, cell biomass, migration and invasion and induction of tumour xenografts in nude mice. MCT knockdown led to a decrease in in vitro tumour cell aggressiveness, with decreased lactate transport, cell proliferation, migration and invasion and, importantly, to an inhibition of in vivo tumour formation and growth.

CONCLUSIONS

This work supports MCTs as promising targets in cancer therapy, demonstrates the contribution of MCTs to cancer cell aggressiveness and, more importantly, shows, for the first time, the disruption of in vivo breast tumour growth by targeting lactate transport.

A homeobox protein, NKX6.1, up-regulates interleukin-6 expression for cell growth in basal-like breast cancer cells

Among breast cancer subtypes, basal-like breast cancer is particularly aggressive, and research on the molecules involved in its pathology might contribute to therapy. In this study, we found that expression of NKX6.1, a homeobox transcription factor, is higher in basal-like breast cancer than in other subtypes. In loss-of-function experiments on basal-like breast cancer cell lines, NKX6.1-depleted cells exhibited reduced cell growth. Because cytokine interleukin-6 (IL-6) is expressed in basal-like breast cancer, and increases cell growth, we analyzed expression levels of IL6, an IL-6 gene, and observed reduced IL6 expression in NKX6.1-depleted cells. In a reporter assay, IL6 promoter activity was reduced by loss of NKX6.1 function. A pull-down assay showed that NKX6.1 binds to the proximal region in IL6 promoter. These results indicate that NKX6.1 directly up-regulates IL6 expression. To investigate further, we established cells with forced expression of IL-6. We observed that exogenous IL-6 expression restored the reduced cell growth of NKX6.1-depleted cells. Furthermore, orthotopic xenografts showed that NKX6.1-depleted cells lost the capacity for tumor formation. We therefore conclude that NKX6.1 is a factor for IL-6-regulated growth and tumor formation in basal-like breast cancer. Our findings facilitate profound understanding of basal-like breast cancer, and the development of suitable therapy.

lnflammation-induced epigenetic switches in cancer

The link between inflammation and cancer is well established. Chronic inflammation promotes cancer initiation and progression. Various studies showed that the underlying mechanisms involve epigenetic alterations. These epigenetic alterations might culminate into an epigenetic switch that transforms premalignant cells into tumor cells or non-invasive into invasive tumor cells, thereby promoting metastasis. Epigenetic switches require an initiating event, which can be inflammation, whereas the resulting phenotype is inherited without the initiating signal. Epigenetic switches are induced and maintained by DNA methylation, histone modifications, polycomb group (PcG)/trithorax group (TrxG) proteins, and feedback loops consisting of transcription factors and microRNAs. Since epigenetic switches are reversible, they might represent an important basis for the design of novel anticancer therapeutics. This review summarizes published evidence of epigenetic switches in cancer development that are induced by inflammation.

LRIG1 opposes epithelial-to-mesenchymal transition and inhibits invasion of basal-like breast cancer cells

LRIG1, a member of the LRIG family of transmembrane leucine rich repeat-containing proteins, is a negative regulator of receptor tyrosine kinase signaling and a tumor suppressor. LRIG1 expression is broadly decreased in human cancer and in breast cancer, low expression of LRIG1 has been linked to decreased relapse-free survival. Recently, low expression of LRIG1 was revealed to be an independent risk factor for breast cancer metastasis and death. These findings suggest that LRIG1 may oppose breast cancer cell motility and invasion, cellular processes which are fundamental to metastasis. However, very little is known of LRIG1 function in this regard. In this study, we demonstrate that LRIG1 is down-regulated during epithelial to mesenchymal transition (EMT) of human mammary epithelial cells, suggesting that LRIG1 expression may represent a barrier to EMT. Indeed, depletion of endogenous LRIG1 in human mammary epithelial cells expands the stem cell population, augments mammosphere formation and accelerates EMT. Conversely, expression of LRIG1 in highly invasive Basal B breast cancer cells provokes a mesenchymal to epithelial transition accompanied by a dramatic suppression of tumorsphere formation and a striking loss of invasive growth in three-dimensional culture. LRIG1 expression perturbs multiple signaling pathways and represses markers and effectors of the mesenchymal state. Furthermore, LRIG1 expression in MDA-MB-231 breast cancer cells significantly slows their growth as tumors, providing the first in vivo evidence that LRIG1 functions as a growth suppressor in breast cancer.

Differential involvement of RASSF2 hypermethylation in breast cancer subtypes and their prognosis

Breast cancer is a heterogeneous disease that can be subdivided into clinical, histopathological and molecular subtypes (luminal A-like, luminal B-like/HER2-negative, luminal B-like/HER2-positive, HER2-positive, and triple-negative). The study of new molecular factors is essential to obtain further insights into the mechanisms involved in the tumorigenesis of each tumor subtype. RASSF2 is a gene that is hypermethylated in breast cancer and whose clinical value has not been previously studied. The hypermethylation of RASSF1 and RASSF2 genes was analyzed in 198 breast tumors of different subtypes. The effect of the demethylating agent 5-aza-2'-deoxycytidine in the re-expression of these genes was examined in triple-negative (BT-549), HER2 (SK-BR-3), and luminal cells (T-47D). Different patterns of RASSF2 expression for distinct tumor subtypes were detected by immunohistochemistry. RASSF2 hypermethylation was much more frequent in luminal subtypes than in non-luminal tumors (p = 0.001). The re-expression of this gene by lentiviral transduction contributed to the differential cell proliferation and response to antineoplastic drugs observed in luminal compared with triple-negative cell lines. RASSF2 hypermethylation is associated with better prognosis in multivariate statistical analysis (P = 0.039). In conclusion, RASSF2 gene is differently methylated in luminal and non-luminal tumors and is a promising suppressor gene with clinical involvement in breast cancer.

MicroRNAs expression in triple negative vs non triple negative breast cancer in Tunisia: interaction with clinical outcome

Introduction

MicroRNAs are small, non coding regulatory molecules containing approximately 21 to 25 nucleotides. They function as controllers of expression at post transcriptional levels of most human protein-coding genes and play an essential role in cell signaling pathways. The objective of the present study is to evaluate the expression profile of the following micro-RNAs: miR-10b, miR-17, miR-21, miR-34a, miR-146a, miR-148a and miR-182, and to determine their possible interaction in triple-negative and non triple-negative primary breast cancers based on clinical outcome.

Methods

60 triple-negative and non triple-negative breast cancer cases, along with their corresponding normal samples were investigated in relation to the expression of the seven studied miRNAs using qPCR Syber Green.

Results

We observed that miR-21, miR-146a and miR-182 were significantly over expressed in triple negative breast cancer. Moreover, miR-10b, miR-21 and miR-182 were significantly associated to lymph node metastases occurrence in triple negative breast carcinoma while only miR-10b was associated with grade III in non triple negative breast cancer cases. Almost all the analyzed microRNAs were strongly associated with patients’ genico-obstetric history in non triple negative breast cancer cases except for miR-34a. All the studied microRNAs were strongly correlated with the use of the contraceptive pills in non triple negative breast cancer groups. The additive effect of hormonal factors in triple negative breast cancer cases showed an association with all the studied miRs except for miR-34 and miR-146a.

Conclusion

The studied microRNAs are strongly influenced by environmental factors especially with hormonal patients’ history. Moreover, miR-10b, miR-21 and miR-182 could be defined as biomarkers in breast cancer to predict both lymph node metastases and grade III occurrence.

Obesity and resistance to cancer chemotherapy: interacting roles of inflammation and metabolic dysregulation

The prevalence of obesity, an established risk factor for many chronic diseases, including several types of cancer, has risen steadily over the past four decades in the United States and worldwide. To date, research in this area has focused on the epidemiologic associations between obesity and cancer risk, as well as on the mechanisms underlying those associations. However, an emerging but understudied issue of clinical importance is the diminution of chemotherapeutic efficacy in obese cancer patients. The mechanisms underlying the negative impact of obesity on therapeutic responses are likely multifactorial. The effects of obesity on chemotherapy drug pharmacokinetics and dosage have been extensively reviewed elsewhere, so this review will focus on the interplay among obesity, increased inflammation, metabolic perturbations, and chemoresistance. The ultimate goal of this review is to delineate areas for future research that could lead to the identification of new targets and strategies for improved cancer outcomes in obese patients.