Triple Negative Breast Cancer: A Tale of Two Decades

Osteopontin promotes tumor growth and metastasis and GPX4-mediated anti-lipid peroxidation in triple-negative breast cancer by activating the PI3k/Akt/mTOR pathway

PURPOSE

Triple-negative breast cancer (TNBC) features high aggressiveness, metastasis rate, drug resistance as well as poor prognosis. Osteopontin (OPN) is a key protein in the process of osteogenesis and has emerged as a new tumor marker in recent years.

METHODS

Cell viability was tested with the CCK-8 kit. Transwell and wound healing were adopted to test cell invasive and migratory abilities. Tumor sphere formation was detected by tumor sphere formation assay. Human umbilical vein endothelial cell (HUVEC) tube formation assay was used to measure the angiogenesis of tumor cells. Western blot was applied for the estimation of the expression of cancer stem cell markers, angiogenesis-, signaling pathway-related proteins as well as OPN. Bioinformatics tools predicted OPN expression in breast cancer tissues. The levels of oxidative stress-related markers were assessed with ELISA. Following the overexpression of OPN in MD-MB-436 cells and the addition of the PI3K/AKT/mTOR pathway inhibitor LY294002, the aforementioned functional experiments were implemented again to investigate the mechanism. Finally, in vivo experiments of tumor-bearing mice were performed for further verification.

RESULTS

The proliferative, invasive, migratory and tumor sphere formation capabilities as well as angiogenesis of TNBC cells were conspicuously increased in contrast to non-TNBC cell lines. OPN expression in TNBC tissues and cells was dramatically enhanced. OPN upregulation significantly elevated cell proliferative, invasive and migratory capabilities as well as tumor sphere formation and angiogenesis. The mechanism might be achieved by activating PI3K/AKT/mTOR signaling to regulate glutathione peroxidase 4 (GPX4)-mediated anti-lipid peroxidation.

CONCLUSION

OPN promoted tumor sphere formation and angiogenesis in TNBC by activating the PI3K/AKT/mTOR pathway to regulate GPX4-mediated anti-lipid peroxidation levels.

Design and synthesis of 4-aminophenol-1,3,4-oxadiazole derivative potentiates apoptosis by targeting MAP kinase in triple negative breast cancer cells

Women below 40 years greatly suffer from triple negative breast cancers (TNBCs). Compared to other breast cancer cases, the poor prognosis and lower survival rate of TNBC patients make it an alarming task to save the human era from this dreadful disease. Therefore, identifying potential novel leads is urgently required to combat the TNBC. To discover a novel anticancer agent, we synthesized a series of novel 4-aminophenolbenzamide-1,3,4 oxadiazole hybrid analogues (7a-l). The structure of the compounds was confirmed by spectral methods (1H & 13C NMR, IR and MS). All the compounds were subjected to their in-silico and in-vitro antiproliferative studies against the TNBC cell lines MDA-MB-468 and MDA-MB-231. The investigations revealed that 7i has significantly promoted apoptosis against MDA-MB-468 and MDA-MB-231 cells with IC50 values of 16.89 and 19.43 µM, respectively. Molecular docking of 7i, with MAPK has exhibited the highest binding score of -7.10 kcal/mol by interacting with crucial amino acids present at the active sites. Molecular docking is further validated with molecular dynamic studies with simulation for 100 ns, depicting various stable interactions with MAPK. Compound 7i, forms stable H-bonds and π-π stacking with amino acid residues. Molecular dynamic simulation (MDS) reveals that hydrophobic and water bridges were very prominent for 7i to bind, with the amino acid residues in close proximity to the active site of p38 MAPK. The investigations show that the In-vitro antiproliferative study of 7i agreed with the in-silico studies. Collectively, our investigations depict 7i as a potent novel lead for the inhibition of TNBCs by targeting p38 MAPK.Communicated by Ramaswamy H. Sarma.

Capecitabine-based chemotherapy in early-stage triple-negative breast cancer: a meta-analysis

Introduction

The efficacy and safety of adjuvant capecitabine in early-stage triple-negative breast cancer remains undefined. A meta-analysis was conducted to elucidate whether capecitabine-based regimens could improve survival in early-stage triple-negative breast cancer (TNBC).

Methods

The current study searched Medline, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov proceedings up to 2023.9. Disease-free survival (DFS), overall survival (OS), and grade 3-4 adverse events (AEs) were assessed. Extracted or calculated hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were pooled.

Results

The capecitabine-based regimens showed significant advantages in DFS (HR = 0.81, 95% CI: 0.73-0.90; P <.001) and OS (HR = 0.75, 95% CI: 0.65-0.87; P <.001) from 12 randomized controlled trials (RCTs) with 5,390 unselected participants. Subgroup analysis of DFS showed analogous results derived from patients with lymph node negative (HR = 0.68, 95% CI: 0.50-0.92; P = .006) and capecitabine duration no less than six cycles (HR = 0.73; 95% CI: 0.62-0.86; P <.001). Improvement of DFS in the addition group (HR = 0.77, 95% CI: 0.68-0.87; P <.001) and adjuvant setting (HR = 0.79, 95% CI: 0.70-0.89; P <.001) was observed. As to safety profile, capecitabine was associated with more frequent stomatitis (OR = 5.05, 95% CI: 1.45-17.65, P = .011), diarrhea (OR = 6.11, 95% CI: 2.12-17.56; P =.001), and hand-foot syndrome (OR = 31.82, 95% CI: 3.23-313.65, P = .003).

Conclusions

Adjuvant capecitabine-based chemotherapy provided superior DFS and OS to early-stage TNBC. The benefits to DFS in selected patients with lymph node negative and the addition and extended duration of capecitabine were demonstrated.

Small EV in plasma of triple negative breast cancer patients induce intrinsic apoptosis in activated T cells

Small extracellular vesicles (sEV) in TNBC patients' plasma promote T cell dysfunction and tumor progression. Here we show that tumor cell-derived exosomes (TEX) carrying surface PDL-1, PD-1, Fas, FasL, TRAIL, CTLA-4 and TGF-β1 induce apoptosis of CD8+T and CD4+T cells but spare B and NK cells. Inhibitors blocking TEX-induce receptor/ligand signals and TEX pretreatments with proteinase K or heat fail to prevent T cell apoptosis. Cytochalasin D, Dynosore or Pit Stop 2, partly inhibit TEX uptake but do not prevent T cell apoptosis. TEX entry into T cells induces cytochrome C and Smac release from mitochondria and caspase-3 and PARP cleavage in the cytosol. Expression of survival proteins is reduced in T cells undergoing apoptosis. Independently of external death receptor signaling, TEX entry into T cells induces mitochondrial stress, initiating relentless intrinsic apoptosis, which is responsible for death of activated T cells in the tumor-bearing hosts. The abundance of TEX in cancer plasma represents a danger for adoptively transferred T cells, limiting their therapeutic potential.

Luminal androgen receptor (LAR) subtype of triple-negative breast cancer: molecular, morphological, and clinical features

According to the classification presented by Lehmann BD (2016), triple-negative breast cancer (TNBC) is a heterogeneous group of malignant tumors with four specific subtypes: basal-like (subtype 1 and subtype 2), mesenchymal, and luminal androgen receptor (LAR) subtypes. The basal-like subtypes of carcinomas predominate in this group, accounting for up to 80% of all cases. Despite the significantly lower proportions of mesenchymal and LAR variants in the group of breast carcinomas with a TNBC profile, such tumors are characterized by aggressive biological behavior. To this end, the LAR subtype is of particular interest, since the literature on such tumors presents different and even contradictory data concerning the disease course and prognosis. This review is devoted to the analysis of the relevant literature, reflecting the main results of studies on the molecular properties and clinical features of the disease course of LAR-type TNBC carcinomas.

Preclinical PET Imaging of Granzyme B Shows Promotion of Immunological Response Following Combination Paclitaxel and Immune Checkpoint Inhibition in Triple Negative Breast Cancer

Advancements in monitoring and predicting of patient-specific response of triple negative breast cancer (TNBC) to immunotherapy (IMT) with and without chemotherapy are needed. Using granzyme B-specific positron emission tomography (GZP-PET) imaging, we aimed to monitor changes in effector cell activation in response to IMT with chemotherapy in TNBC. TNBC mouse models received the paclitaxel (PTX) ± immune checkpoint inhibitors anti-programmed death 1 (anti-PD1) and anti-cytotoxic T-lymphocyte 4 (anti-CTLA4). GZP-PET imaging was performed on treatment days 0, 3, and 6. Mean standard uptake value (SUVmean), effector cell fractions, and SUV histograms were compared. Mice were sacrificed at early imaging timepoints for cytokine and histological analyses. GZP-PET imaging data revealed differences prior to tumor volume changes. By day six, responders had SUVmean ≥ 2.2-fold higher (p < 0.0037) and effector cell fractions ≥ 1.9-fold higher (p = 0.03) compared to non-responders. IMT/PTX resulted in a significantly different SUV distribution compared to control, indicating broader distribution of activated intratumoral T-cells. IMT/PTX resulted in significantly more necrotic tumor tissue and increased levels of IL-2, 4, and 12 compared to control. Results implicate immunogenic cell death through upregulation of key Th1/Th2 cytokines by IMT/PTX. Noninvasive PET imaging can provide data on the TNBC tumor microenvironment, specifically intratumoral effector cell activation, predicting response to IMT plus chemotherapy.

Role of MicroRNAs and Long Non-Coding RNAs in Regulating Angiogenesis in Human Breast Cancer- A Molecular Medicine Perspective

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are proficient in regulating gene expression post-transcriptionally. Considering the recent trend in exploiting non-coding RNAs (ncRNAs) as cancer therapeutics, the potential use of miRNAs and lncRNAs as biomarkers and novel therapeutic agents against angiogenesis is an important scientific aspect. An estimated 70% of the genome is actively transcribed, only 2% of which codes for known protein-coding genes. Long noncoding RNAs (lncRNAs) are a large and diverse class of RNAs > 200 nucleotides in length, and not translated into protein, and are of utmost importance and it governs the expression of genes in a temporal, spatial, and cell context-dependent manner. Angiogenesis is an essential process for organ morphogenesis and growth during development, and it is relevant during the repair of wounded tissue in adults. It is coordinated by an equilibrium of pro-and anti-angiogenic factors; nevertheless, when affected, it promotes several diseases, including breast cancer. Signaling pathways involved here are tightly controlled systems that regulate the appropriate timing of gene expression required for the differentiation of cells down a particular lineage essential for proper tissue development. Lately, scientific reports are indicating that ncRNAs, such as miRNAs, and lncRNAs, play critical roles in angiogenesis related to breast cancer. The specific roles of various miRNAs and lncRNAs in regulating angiogenesis in breast cancer, with particular focus on the downstream targets and signaling pathways regulated by these ncRNAs with molecular medicine perspective, are highlighted in this write-up.

TGF-β-Induced TMEPAI Promotes Epithelial-Mesenchymal Transition in Doxorubicin-Treated Triple-Negative Breast Cancer Cells via SMAD3 and PI3K/AKT Pathway Alteration

Introduction

Epithelial–mesenchymal transition (EMT) and overexpression of drug efflux transporters have been reported to cause doxorubicin resistance. Our previous study indicated that TMEPAI (transmembrane prostate androgen-induced protein) attenuated doxorubicin sensitivity in triple-negative breast cancer cells. However, how TMEPAI contributes to doxorubicin resistance in TNBC remains unclear. Thus, the present study aimed to elucidate the mechanism of TMEPAI in doxorubicin resistance in triple-negative breast cancer cells.

Methods

We used BT549, triple-negative cells wild type (WT), and BT549 TMEPAI knock-out. Both cells were treated with TGF-β 2 ng/mL for 24 hours, followed by TGF-β 2 ng/mL and doxorubicin 12.9 nM for another 24 hours. Afterward, the cells were harvested and counted. Cells were further lysed and used for RT-PCR and Western blot analysis. We determined the expression levels of proliferation, apoptosis, EMT markers, and drug efflux transporters. Additionally, we investigated the expressions of PI3K as well as SMAD3 and AKT phosphorylation.

Results

TNBC cells were shown to be less sensitive to doxorubicin in the presence of TMEPAI. TMEPAI was shown to alleviate the mRNA expressions of apoptosis markers: Bax, Bcl2, Caspase-3, and Caspase-9. Our results indicated that the presence of TMEPAI greatly amplifies EMT and increases drug efflux transporter expressions after doxorubicin treatment. Furthermore, our findings demonstrated that TMEPAI reduced the action of doxorubicin in inhibiting SMAD3 phosphorylation. TMEPAI was also shown to modify the effect of doxorubicin by reducing PI3K expressions and Akt phosphorylation in triple-negative breast cancer cells.

Conclusion

Our findings indicate that TMEPAI promotes EMT and drug efflux transporters at least in part by shifting doxorubicin action from SMAD3 phosphorylation reduction to PI3K/AKT inhibition in triple-negative breast cancer cells.

CircRNA hsa_circ_0006220 acts as a tumor suppressor gene by regulating miR-197-5p/CDH19 in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is one of the most aggressive breast cancer (BC) subtypes. Circular ribonucleic acids (circRNAs) are a class of novel stable and conserved forms of ribonucleic acids (RNAs). circRNAs have been documented to be involved in multiple diseases, especially malignancies, through a competing endogenous RNA (ceRNA) mechanism. However, few studies have been conducted on the function of circRNAs in TNBC. Previously, hsa_circ_0006220 was found to be downregulated in BC tissues. The present study sought to explore the mechanism of hsa_circ_0006220 in TNBC progression.

Methods

A real-time polymerase chain reaction (PCR) was used to validate the expression of hsa_circ_0006220 in TNBC tissues and cells. In addition, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), wound-healing and Transwell assays were conducted to measure the inhibition effects of hsa_circ_0006220 on TNBC cells in vitro. Further, a dual-luciferase reporter assay was performed to confirm the interaction between hsa_circ_0006220 and miR-197-5p. A mimic and an inhibitor of miR-197-5p were constructed to confirm the downstream mechanism of hsa_circ_0006220 in TNBC cells.

Results

Hsa_circ_0006220 was more downregulated in TNBC than other subtypes of BC tissues and cell lines. In vitro data showed that hsa_circ_0006220 remarkably inhibited the proliferation, migration, and invasion of TNBC cells. Further, hsa_circ_0006220 was confirmed to be a sponge of miR-197-5p, and to indirectly regulate CDH19 expression. A rescue assay indicated the biological function of the hsa_circ_0006220/miR-197-5p/CDH19 pathway in TNBC cells.

Conclusions

hsa_circ_0006220 plays an inhibitory role in TNBC progression. It might be a potential diagnostic marker and therapeutic target for TNBC patients.

miR-522 regulates cell proliferation, migration, invasion capacities and acts as a potential biomarker to predict prognosis in triple-negative breast cancer

This study was designed to explore the cell functions and prognostic significance of miR-522 in triple-negative breast cancer. The expression levels of miR-522 in triple-negative breast cancer tissues and cell lines were detected by quantitative real-time PCR analysis. Kaplan-Meier curve and Cox regression analysis were used to investigate the relationship between miR-522 expression and prognosis of patients, and to evaluate the possibility of miR-522 as a potential indicator for predicting the prognosis of triple-negative breast cancer. The CCK-8 and transwell assays were used to assess cell proliferation, migration, and invasion abilities. The expression of miR-522 in triple-negative breast cancer tissues was significantly higher than that in adjacent tissues and its high expression was closely associated with the high incidence of lymph node metastasis, advanced TNM stage, and BRCA1/2 mutation status. High expression of miR-522 is correlated with poor overall survival in patients with triple-negative breast cancer. Besides, functional studies in two triple-negative breast cancer cell lines showed that overexpression of miR-522 significantly promoted cell proliferation, migration, and invasion in vitro. BRCA1 was a potential direct target of miR-522. Our findings indicated that miR-522 was highly expressed in triple-negative breast cancer and was associated with poor prognosis of patients. The upregulation of miR-522 accelerated the progression of triple-negative breast cancer by targeting BRCA1. Therefore, miR-522 provides valuable information for the development of prevention and treatment strategies.

Pathogenesis and Potential Therapeutic Targets for Triple-Negative Breast Cancer

Triple negative breast cancer (TNBC) is a heterogeneous tumor characterized by early recurrence, high invasion, and poor prognosis. Currently, its treatment includes chemotherapy, which shows a suboptimal efficacy. However, with the increasing studies on TNBC subtypes and tumor molecular biology, great progress has been made in targeted therapy for TNBC. The new developments in the treatment of breast cancer include targeted therapy, which has the advantages of accurate positioning, high efficiency, and low toxicity, as compared to surgery, radiotherapy, and chemotherapy. Given its importance as cancer treatment, we review the latest research on the subtypes of TNBC and relevant targeted therapies.

Real-World Clinical Outcomes in Biological Subgroups of Breast Cancer in the Hospital District of Southwest Finland

BACKGROUND

Comparing breast cancer survival trends globally, Finland is among the top three countries in Europe. However, outcome data on breast cancer subgroups in the Finnish population are limited. This retrospective, registry-based study aimed to assess patient characteristics and clinical outcomes of different breast cancer subgroups in early (EBC) and metastatic breast cancer (MBC) in a real-life clinical setting.

MATERIALS AND METHODS

The study consisted of 6,977 adult, female patients with breast cancer diagnosed in Southwest Finland during 2005-2018. Patients were divided into four mutually exclusive groups: human epidermal growth factor receptor 2 positive (HER2+), triple negative, HER2-/hormone receptor positive (HR+), and HER2 and/or HR status unknown, and further into patients with EBC and MBC. Overall survival (OS) was assessed as a clinical outcome, as well as the following real-world (rw) clinical outcomes: disease-free survival (rwDFS), progression-free survival (rwPFS), and distant recurrence-free interval (rwDRFI).

RESULTS

Within EBC, 5-year survival was the highest (88%) in HER2-/HR+, followed by 85% in HER2+, and 75% in triple negative. The rwDFS varied significantly in EBC (5-year rwDFS HER2 -/HR+, HER2+, triple negative: 87%, 80%, 71% respectively). In MBC, median survival was 2 years for both HER2-/HR+ and HER2+ and markedly shorter for triple negative (0.8 years). Independent predictors of mortality were age (hazard ratio [HR], 1.1), other subgroups than HER2-/HR+ (HR, 1.2-1.9), metastatic disease (HR, 9.8), and other malignancies (HR, 2.7).

CONCLUSION

This registry-based study demonstrates significant differences in breast cancer outcomes on the subgroup level, as well as poorer outcomes compared with clinical trials, giving complementary insight on clinical characteristics in an unselected patient population.

IMPLICATIONS FOR PRACTICE

This retrospective, registry-based study assessed the clinical outcomes of different breast cancer subgroups in 6,977 adult, female patients with breast cancer diagnosed in Southwest Finland during 2005-2018. Results demonstrated significant variation in the survival between subgroups in both early breast cancer and metastatic breast cancer, as well as differences between unselected patients representing the standard of care and randomized clinical trials. Although, according to the global comparison of survival trends, the net survival of patients with breast cancer in Finland is generally high, there is great variation between subgroups. These real-life breast cancer data provide tools to further evaluate medical need in different breast cancer subgroups.

A ten N6-methyladenosine-related long non-coding RNAs signature predicts prognosis of triple-negative breast cancer

Background

Patients with triple‐negative breast cancer (TNBC) face a major challenge of the poor prognosis, and N6‐methyladenosine‐(m6A) mediated regulation in cancer has been proposed. Therefore, this study aimed to explore the prognostic roles of m6A‐related long non‐coding RNAs (LncRNAs) in TNBC.

Methods

Clinical information and expression data of TNBC samples were collected from TCGA and GEO databases. Pearson correlation, univariate, and multivariate Cox regression analysis were employed to identify independent prognostic m6A‐related LncRNAs to construct the prognostic score (PS) risk model. Receiver operating characteristic (ROC) curve was used to evaluate the performance of PS risk model. A competing endogenous RNA (ceRNA) network was established for the functional analysis on targeted mRNAs.

Results

We identified 10 independent prognostic m6A‐related LncRNAs (SAMD12‐AS1, BVES‐AS1, LINC00593, MIR205HG, LINC00571, ANKRD10‐IT1, CIRBP‐AS1, SUCLG2‐AS1, BLACAT1, and HOXB‐AS1) and established a PS risk model accordingly. Relevant results suggested that TNBC patients with lower PS had better overall survival status, and ROC curves proved that the PS model had better prognostic abilities with the AUC of 0.997 and 0.864 in TCGA and GSE76250 datasets, respectively. Recurrence and PS model status were defined as independent prognostic factors of TNBC. These ten LncRNAs were all differentially expressed in high‐risk TNBC compared with controls. The ceRNA network revealed the regulatory axes for nine key LncRNAs, and mRNAs in the network were identified to function in pathways of cell communication, signaling transduction and cancer.

Conclusion

Our findings proposed a ten‐m6A‐related LncRNAs as potential biomarkers to predict the prognostic risk of TNBC.

[Triple-negative breast cancer. Modern molecular genetic concepts and their clinical significance]

Triple negative breast cancer (BC) is a heterogeneous group of carcinomas that substantially differ in clinical, morphological, and molecular genetic characteristics, tumor response to chemotherapy, and prognosis. These features define triple negative BC today as a special clinical problem that has not yet been completely solved. The review is devoted to the description and systematization of the currently available literature data concerning molecular and genetic features and differences in a fairly significant group of breast carcinomas with a severe, aggressive course and an extremely poor prognosis. The review presents the existing molecular genetic classification of triple negative BC based on the results of studies conducted by M.D. Burstein (2015) and B.D. Lehmann (2016), which determines the presence of 4 tumor-specific subtypes: basal-like type (type 1 and type 2), mesenchymal, and luminal androgen receptor types. The paper reflects the main stages of transformation of the proposed classification over the past decade and an attempt has been make to describe the molecular characteristics of each subtype of these carcinomas.

Autocrine TGFβ1 Opposes Exogenous TGFβ1-Induced Cell Migration and Growth Arrest through Sustainment of a Feed-Forward Loop Involving MEK-ERK Signaling

Simple Summary

Transforming growth factor (TGF) β signaling is intimately involved in nearly all aspects of tumor development and is known for its role as both a tumor suppressor in benign tissues and a tumor promoter in advanced cancers. This dual role is also reflected by cancer cell-produced TGFβ that eventually acts on the same cell(s) in an autocrine fashion. Recently, we observed that endogenous TGFB1 can inhibit rather than stimulate cell motility in cell lines with high autocrine TGFβ production. The unexpected anti-migratory role prompted us to evaluate how autocrine TGFβ1 impacts the cells’ migratory and proliferative responses to exogenous (recombinant human) TGFβ. Surprisingly, endogenous TGFB1 opposed the migratory and growth-inhibitory responses induced by exogenous TGFβ1 by driving a self-perpetuating feedforward loop involving MEK-ERK signaling. Our observation has implications for the use of TGFβ signaling inhibitors in cancer therapy.

Abstract

Autocrine transforming growth factor β (aTGFβ) has been implicated in the regulation of cell invasion and growth of several malignant cancers such as pancreatic ductal adenocarcinoma (PDAC) or triple-negative breast cancer (TNBC). Recently, we observed that endogenous TGFB1 can inhibit rather than stimulate cell motility in cell lines with high aTGFβ production and mutant KRAS, i.e., Panc1 (PDAC) and MDA-MB-231 (TNBC). The unexpected anti-migratory role prompted us to evaluate if aTGFβ1 may be able to antagonize the action of exogenous (recombinant human) TGFβ (rhTGFβ), a well-known promoter of cell motility and growth arrest in these cells. Surprisingly, RNA interference-mediated knockdown of the endogenous TGFB1 sensitized genes involved in EMT and cell motility (i.e., SNAI1) to up-regulation by rhTGFβ1, which was associated with a more pronounced migratory response following rhTGFβ1 treatment. Ectopic expression of TGFB1 decreased both basal and rhTGFβ1-induced migratory activities in MDA-MB-231 cells but had the opposite effect in Panc1 cells. Moreover, silencing TGFB1 reduced basal proliferation and enhanced growth inhibition by rhTGFβ1 and induction of cyclin-dependent kinase inhibitor, p21^WAF1. Finally, we show that aTGFβ1 promotes MEK-ERK signaling and vice versa to form a self-perpetuating feedforward loop that is sensitive to SB431542, an inhibitor of the TGFβ type I receptor, ALK5. Together, these data suggest that in transformed cells an ALK5-MEK-ERK-aTGFβ1 pathway opposes the promigratory and growth-arresting function of rhTGFβ1. This observation has profound translational implications for TGFβ signaling in cancer.

The Ratio of RAC1B to RAC1 Expression in Breast Cancer Cell Lines as a Determinant of Epithelial/Mesenchymal Differentiation and Migratory Potential

Breast cancer (BC) is a heterogenous disease encompassing tumors with different histomorphological phenotypes and transcriptionally defined subtypes. However, the non-mutational/epigenetic alterations that are associated with or causally involved in phenotype diversity or conversion remain to be elucidated. Data from the pancreatic cancer model have shown that the small GTPase RAC1 and its alternatively spliced isoform, RAC1B, antagonistically control epithelial–mesenchymal transition and cell motility induced by transforming growth factor β. Using a battery of established BC cell lines with either a well-differentiated epithelial or poorly differentiated mesenchymal phenotype, we observed subtype-specific protein expression of RAC1B and RAC1. While epithelial BC lines were RAC1B^high and RAC1^low, mesenchymal lines exhibited the reverse expression pattern. High RAC1B and/or low RAC1 abundance also correlated closely with a poor invasion potential, and vice versa, as revealed by measuring random cell migration (chemokinesis), the preferred mode of cellular movement in cells that have undergone mesenchymal transdifferentiation. We propose that a high RAC1B:RAC1 ratio in BC cells is predictive of an epithelial phenotype, while low RAC1B along with high RAC1 is a distinguishing feature of the mesenchymal state. The combined quantitative assessment of RAC1B and RAC1 in tumor biopsies of BC patients may represent a novel diagnostic tool for probing molecular subtype and eventually predict malignant potential of breast tumors.

The role of capecitabine-based neoadjuvant and adjuvant chemotherapy in early-stage triple-negative breast cancer: a systematic review and meta-analysis

BACKGROUND

The role of capecitabine in neoadjuvant and adjuvant chemotherapy for early-stage triple-negative breast cancer (TNBC) is highly controversial. Our meta-analysis was designed to further elucidate the effects of capecitabine on survival in early-stage TNBC patients and its safety.

METHODS

PubMed, Embase, and papers presented at several main conferences were searched up to December 19, 2019, to investigate capecitabine-based versus capecitabine-free neoadjuvant and adjuvant chemotherapy in TNBC patients. Heterogeneity was assessed using I2 test, combined with hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CI) computed for disease-free survival (DFS), overall survival (OS), and over grade 3 adverse events (AEs).

RESULTS

A total of 9 randomized clinical trials and 3842 TNBC patients were included. Overall, the combined capecitabine regimens in neoadjuvant and adjuvant chemotherapy showed significantly improved DFS (HR = 0.75; 95% CI, 0.65-0.86; P < 0.001) and OS (HR = 0.63; 95% CI, 0.53-0.77; P < 0.001). In subgroup analysis, there were improvements in DFS in the groups with addition of capecitabine (HR = 0.64; 95% CI, 0.53-0.78; P < 0.001), adjuvant chemotherapy (HR = 0.73; 95% CI, 0.63-0.85; P < 0.001), and lymph node positivity (HR = 0.62; 95% CI, 0.44-0.86; P = 0.005). Capecitabine regimens were related to higher risks of diarrhea (OR = 2.88, 95% CI 2.23-3.74, P < 0.001), stomatitis (OR = 2.01, 95% CI 1.53-2.64, P < 0.001) and hand-foot syndrome (OR = 8.67, 95% CI 6.70-11.22, P < 0.001).

CONCLUSION

This meta-analysis showed that neoadjuvant and adjuvant chemotherapy combined with capecitabine significantly improved both DFS and OS in early-stage TNBC patients with tolerable AEs. There were benefits to DFS in the groups with the addition of capecitabine, adjuvant chemotherapy, and lymph node positivity.

A review of current progress in triple-negative breast cancer therapy

Triple-negative breast cancer (TNBC) is a particularly aggressive subtype known for its extremely high drug resistance, progression, poor prognosis, and lack of clear therapeutic targets. Researchers are aiming to advance TNBC treatment worldwide. In the past 2–3 years, more positive results have emerged in the clinical research on TNBC treatment. Based on the results, several impressive drugs have been approved to benefit patients with TNBC, including the PARP inhibitors olaparib and talazoparib for germline BRCA mutation-associated breast cancer (gBRCAm-BC) and immunotherapy using the checkpoint inhibitor atezolizumab in combination with nab-paclitaxel for programmed cell death-ligand 1-positive (PD-L1+) advanced TNBC. Although neoadjuvant therapy has focused on combinations of systemic agents to optimize pathologically complete response, metastatic TNBC still has a poor prognosis. Innovative multidrug combination systemic therapies based on neoadjuvants and adjuvants have led to significant improvements in outcomes, particularly over the past decade.

BCL11A: a potential diagnostic biomarker and therapeutic target in human diseases

Transcription factor B-cell lymphoma/leukemia 11A (BCL11A) gene encodes a zinc-finger protein that is predominantly expressed in brain and hematopoietic tissue. BCL11A functions mainly as a transcriptional repressor that is crucial in brain, hematopoietic system development, as well as fetal-to-adult hemoglobin switching. The expression of this gene is regulated by microRNAs, transcription factors and genetic variations. A number of studies have recently shown that BCL11A is involved in β-hemoglobinopathies, hematological malignancies, malignant solid tumors, 2p15-p16.1 microdeletion syndrome, and Type II diabetes. It has been suggested that BCL11A may be a potential prognostic biomarker and therapeutic target for some diseases. In this review, we summarize the current research state of BCL11A, including its biochemistry, expression, regulation, function, and its possible clinical application in human diseases.

RAC1B Induces SMAD7 via USP26 to Suppress TGFβ1-Dependent Cell Migration in Mesenchymal-Subtype Carcinoma Cells

The small GTPase RAC1B has been shown to act as a powerful inhibitor of the transforming growth factor (TGF)β type I receptor ALK5 and TGFβ1/ALK5-induced epithelial–mesenchymal transition and cell motility. However, the precise mechanism has remained elusive. RNAi-mediated knockdown of RAC1B in the pancreatic ductal adenocarcinoma (PDAC)-derived cell line Panc1 failed to alter transcriptional activity from a transfected ALK5 promoter–reporter construct. In contrast, pharmacological inhibition of the proteasome decreased the abundance of ALK5 protein in cell lines of the mesenchymal subtype (Panc1, IMIM-PC-1, and breast cancer MDA-MB-231), but not in a PDAC cell line of the epithelial subtype (Colo357). Here, we focused on the inhibitory Smad protein, SMAD7, as a potential candidate for RAC1B-mediated inhibition of cell migration. In Panc1 cells devoid of RAC1B, SMAD7 protein was dramatically reduced and these cells were refractory to TGFβ1-induced upregulation of SMAD7 protein but not mRNA expression. Intriguingly, RNAi-mediated knockdown or ectopic overexpression of SMAD7 in Panc1 cells up- or downregulated, respectively, ALK5 protein expression and mimicked the suppressive effect of RAC1B on TGFβ/SMAD3-dependent transcriptional activity, target gene expression and cell migration. Transfection of SMAD7 was further able to partially rescue cells from the RAC1B knockdown-mediated increase in migratory properties. Conversely, knockdown of SMAD7 was able to partially rescue Panc1 and MDA-MB-231 cells from the antimigratory effect of ectopically expressed RAC1B. Finally, we demonstrate that RAC1B upregulation of SMAD7 protein requires intermittent transcriptional induction of the deubiquitinating enzyme USP26. Our data suggest that RAC1B induces SMAD7 by promoting its deubiquitination and establishes this Smad as one of RAC1B’s downstream effectors in negative regulation of ALK5 and TGFβ1-induced cell migration in mesenchymal-type carcinoma cells.

Expression and clinical significance of MAPK and EGFR in triple-negative breast cancer

To investigate the expression and clinical significance of mitogen-activated protein kinase (MAPK) and epidermal growth factor receptor (EGFR) in triple-negative breast cancer (TNBC), a total of 300 TNBC and 120 paired paracancerous tissues were examined. Immunohistochemistry was conducted to determine the expression levels of MAPK and EGFR, and the correlation between MAPK and EGFR expression was evaluated using Cramer's V test. The association between MAPK and EGFR expression, and various clinicopathological variables (such as lymph node metastasis, clinical stage, recurrence and metastasis) was also evaluated, using the χ2 test. MAPK and EGFR expression levels in TNBC tissues were significantly higher than in the paired paracancerous tissues. Moreover, MAPK expression was associated with that of EGFR in TNBC tissues. The positive expression rates of MAPK and EGFR in patients with lymph node metastasis, advanced clinical stage, tumor recurrence and metastasis were higher than those without. Patients with positive expression of MAPK and EGFR in TNBC tissues had poorer prognoses and lower overall survival times than those without expression. In summary, the expression of MAPK and EGFR is closely associated with tumor invasion and the metastasis of TNBC, and may therefore be used as an indicator of poor prognosis in patients with TNBC.

Quadruple negative breast cancer

Quadruple negative breast cancer (QNBC), lacking the expression of ER (estrogen receptor), PR (progesterone receptor), HER2 (human epidermal growth factor receptor-2) and AR (androgen receptor), was regarded as one breast cancer subtype with the worst prognosis. Recently, the molecular features of QNBC are not well understood. Different from AR-positive triple-negative breast cancer, QNBC is insensitive to conventional chemotherapeutic agents and has no efficient treatment targets. However, QNBC has been shown to express unique proteins that may be amenable to use in the development of targeted therapies. Here we reviewed the features of QNBC and proteins that may serve as effective targets for QNBC treatment, such as ACSL4, SKP2, immune checkpoint inhibitors, EGFR, MicroRNA signatures and Engrailed 1.

Palladium(ii) complexes bearing 1-iminothiolate-3,5-dimethylpyrazoles: synthesis, cytotoxicity, DNA binding and enzymatic inhibition studies

This work describes the enzymatic inhibitory activity of four novel Pd(ii) complexes towards topoisomerase IIα and cathepsins B and L.In silicostudies agree well with the enhancedin vitrocathepsin B inhibition induced by compound4(58% at 10 μM).

Adjuvant addition of capecitabine to early-stage triple-negative breast cancer patients receiving standard chemotherapy: a meta-analysis

PURPOSE

Triple-negative breast cancer (TNBC) pertains to a breast cancer subtype that has the highest metastatic and recurrence rates. The effectiveness of capecitabine as adjuvant chemotherapy for TNBC has remained unclear. This study conducted a meta-analysis of the efficacy of capecitabine as adjuvant chemotherapy for early-stage TNBC treated with taxane-/anthracycline-based chemotherapy.

METHODS

We identified relevant research reports in online databases until May 2019. We finally included seven randomized clinical trials to perform this meta-analysis. Altogether, the seven trials enrolled 3151 early-stage TNBC patients, with 1552 receiving standard (neo)adjuvant chemotherapy regimens and 1599 receiving addition of capecitabine in the adjuvant settings besides standard regimens.

RESULTS

A meta-analysis of the seven trials revealed a significant increase in disease-free survival (DFS) with the addition of capecitabine (Hazard ratio (HR) = 0.77, 95% CI 0.66-0.90). This improvement in DFS was significant both in trials conducted in America-Europe and in Asia. In trials involving six to eight cycles of capecitabine addition, we observed a significant improvement in DFS. Furthermore, in the meta-analysis of six trials, we detected a significant increase in overall survival (OS) favoring capecitabine (HR = 0.69, 95% CI 0.56-0.85).

CONCLUSIONS

Adjuvant addition of capecitabine to early-stage TNBC patients receiving standard chemotherapy showed significant DFS and OS improvement. Future studies involving the selection of patients that may have the highest survival benefit from adding capecitabine are warranted.

Research Progress of the Functional Role of ACK1 in Breast Cancer

ACK1 is a nonreceptor tyrosine kinase with a unique structure, which is tightly related to the biological behavior of tumors. Previous studies have demonstrated that ACK1 was involved with multiple signaling pathways of tumor progression. Its crucial role in tumor cell proliferation, apoptosis, invasion, and metastasis was tightly related to the prognosis and clinicopathology of cancer. ACK1 has a unique way of regulating cellular pathways, different from other nonreceptor tyrosine kinases. As an oncogenic kinase, recent studies have shown that ACK1 plays a critical regulatory role in the initiation and progression of tumors. In this review, we will be summarizing the structural characteristics, activation, and regulation of ACK1 in breast cancer, aiming to deeply understand the functional and mechanistic role of ACK1 and provide novel therapeutic strategies for breast cancer treatment.

HDAC inhibitors induce proline dehydrogenase (POX) transcription and anti-apoptotic autophagy in triple negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with poor clinical outcomes and without effective targeted therapies. Numerous studies have suggested that HDAC inhibitors (TSA/SAHA) may be effective in TNBCs. Proline oxidase, also known as proline dehydrogenase (POX/PRODH), is a key enzyme in the proline metabolism pathway and plays a vital role in tumorigenesis. In this study, we found that HDAC inhibitors (TSA/SAHA) significantly increased POX expression and autophagy through activating AMPK. Depletion of POX decreased autophagy and increased apoptosis induced by HDAC inhibitors in TNBC cells. These results suggest that POX contributes to cell survival under chemotherapeutic stresses and might serve as a potential target for treatment of TNBC.

Small molecule HDAC inhibitors: Promising agents for breast cancer treatment

Breast cancer, a heterogeneous disease, is the most frequently diagnosed cancer and the second leading cause of cancer-related death among women worldwide. Recently, epigenetic abnormalities have emerged as an important hallmark of cancer development and progression. Given that histone deacetylases (HDACs) are crucial to chromatin remodeling and epigenetics, their inhibitors have become promising potential anticancer drugs for research. Here we reviewed the mechanism and classification of histone deacetylases (HDACs), association between HDACs and breast cancer, classification and structure-activity relationship (SAR) of HDACIs, pharmacokinetic and toxicological properties of the HDACIs, and registered clinical studies for breast cancer treatment. In conclusion, HDACIs have shown desirable effects on breast cancer, especially when they are used in combination with other anticancer agents. In the coming future, more multicenter and randomized Phase III studies are expected to be conducted pushing promising new therapies closer to the market. In addition, the design and synthesis of novel HDACIs are also needed.

Ecotropic virus integration-1 and calreticulin as novel prognostic markers in triple-negative breast cancer: A retrospective cohort study

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer, for which no specific targete d therapy is currently available. The present study aimed to examine the associations of ecotropic virus integration site 1 (EVI-1) and calreticulin (CRT) with other clinicopathological variables and the prognosis of patients with TNBC. The present retrospective cohort study reviewed the medical records of patients with TNBC treated in the Affiliated Hospitals of Jinzhou Medical University between January 2010 and June 2015. The protein expression levels of EVI-1 and CRT in tumor samples obtained from the patients were examined by immunohistochemical analysis. Univariate and multivariate regression analyses were used to identify associations between clinical characteristics and disease-free survival (DFS) or overall survival (OS). Kaplan-Meier analysis was performed to observe the survival condition (DFS/OS) according to EVI-1 and CRT expression. A total of 88 TNBC patients were included in the present study. Tumor tissues in 52 (59.1%) patients were EVI-1 positive, and tumor tissues in 64 (72.7%) patients were CRT-positive, and these rates were significantly higher compared with those in the corresponding paracancerous tissues (P<0.05). Multivariate analysis revealed that EVI-1 and CRT expression levels were independent variables associated with OS and DFS, and high expression of both CRT and EVI-1 was significantly associated with decreased OS and DFS compared with the other subgroups (low EVI-1/low CRT expression, low EVI-1/high CRT expression and high EVI-1/low CRT expression) of patients with TNBC. EVI-1 and CRT expression in TNBC was significantly correlated with poor outcome. Evaluation of the EVI-1 and CRT status may provide insight into prognosis prediction for patients with TNBC.

Differential Expression and Pathway Analysis in Drug-Resistant Triple-Negative Breast Cancer Cell Lines Using RNASeq Analysis

Triple-negative breast cancer (TNBC) is among the most notorious types of breast cancer, the treatment of which does not give consistent results due to the absence of the three receptors (estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) as well as high amount of molecular variability. Drug resistance also contributes to treatment unresponsiveness. We studied differentially expressed genes, their biological roles, as well as pathways from RNA-Seq datasets of two different TNBC drug-resistant cell lines of Basal B subtype SUM159 and MDA-MB-231 treated with drugs JQ1 and Dexamethasone, respectively, to elucidate the mechanism of drug resistance. RNA sequencing(RNA-Seq) data analysis was done using edgeR which is an efficient program for determining the most significant Differentially Expressed Genes (DEGs), Gene Ontology (GO) terms, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. iPathway analysis was further used to obtain validated results using analysis that takes into consideration type, function, and interactions of genes in the pathway. The significant similarities and differences throw light into the molecular heterogeneity of TNBC, giving clues into the aspects that can be focused to overcome drug resistance. From this study, cytokine-cytokine receptor interaction pathway appeared to be a key factor in TNBC drug resistance.

Gene expression profiling of triple-negative breast tumors with different expression of secreted protein acidic and cysteine rich (SPARC)

Aim: To determine the expression signature of triple-negative breast cancer (TNBC) with differences of secreted protein acidic and rich in cysteine expression and clinical behavior. Patients, materials & methods: cDNA microarray analysis was performed to determine the expression profiling of TNBC, characterized regarding secreted protein acidic and rich in cysteine expression status. Immunohistochemistry analysis on tissue microarrays containing an independent cohort of TNBC was performed for validation. Results: Negative staining of SOHLH2 and positive staining of DNAJC12 and LIM1 was correlated with a poor outcome of the patients. Conclusion: Our findings provide new information on transcriptome changes associated with the clinical behavior of TNBC that may serve as a potential tool for the identification and characterization of new candidate biomarkers.

The ERβ4 variant induces transformation of the normal breast mammary epithelial cell line MCF-10A; the ERβ variants ERβ2 and ERβ5 increase aggressiveness of TNBC by regulation of hypoxic signaling

Triple negative breast cancer (TNBC) still remains a challenge to treat in the clinic due to a lack of good targets for treatment. Although TNBC lacks expression of ERα, the expression of ERβ and its variants are detected quite frequently in this cancer type and can represent an avenue for treatment. We show that two of the variants of ERβ, namely ERβ2 and ERβ5, control aggressiveness of TNBC by regulating hypoxic signaling through stabilization of HIF-1α. RNA-seq of patient derived xenografts (PDX) from TNBC shows expression of ERβ2, ERβ4 and ERβ5 variants in more than half of the samples. Furthermore, expression of ERβ4 in the immortalized, normal mammary epithelial cell line MCF-10A that is resistant to tumorsphere formation caused transformation and development of tumorspheres. By contrast, ERβ1, ERβ2 or ERβ5 were unable to support tumorsphere formation. We have previously shown that all variants except ERβ1 stabilize HIF-1α but only ERβ4 appears to have the ability to transform normal mammary epithelial cells, pointing towards a unique property of ERβ4. We propose that ERβ variants may be good diagnostic tools and also serve as novel targets for treatment of breast cancer.

Combined calcitriol and menadione reduces experimental murine triple negative breast tumor

BACKGROUND

Calcitriol (D) or 1,25(OH)₂D₃ inhibits the growth of several tumor cells including breast cancer cells, by activating cell death pathways. Menadione (MEN), a glutathione-depleting compound, may be used to potentiate the antiproliferative actions of D on cancer cells. We have previously shown in vitro that MEN improved D-induced growth arrest on breast cancer cell lines, inducing oxidative stress and DNA damage via ROS generation. Treatment with MEN+D resulted more effective than D or MEN alone.

OBJECTIVE

To study the in vivo effect of calcitriol, MEN or their combination on the development of murine transplantable triple negative breast tumor M-406 in its syngeneic host.

METHODS

Tumor M-406 was inoculated s.c., and when tumors reached the desired size, animals were randomly assigned to one of four groups receiving daily i.p. injections of either sterile saline solution (controls, C), MEN, D, or both (MEN+D). Body weight and tumor volume were recorded three times a week. Serum calcium was determined before and at the end of the treatment, at which time tumor samples were obtained for histological examination.

RESULTS

None of the drugs, alone or in combination, affected mice body weight in the period studied. The combined treatment reduced tumor growth rate (C vs. MEN+D, P<0.05) and the corresponding histological sections exhibited small remaining areas of viable tumor only in the periphery. A concomitant DNA fragmentation was observed in all treated groups and MEN potentiated the calcitriol effect on tumor growth.

CONCLUSIONS

As previously observed in vitro, treatment with MEN and D delayed tumor growth in vivo more efficiently than the individual drugs, with evident signals of apoptosis induction. Our results propose an alternative protocol to treat triple negative breast cancer, using GSH depleting drugs together with calcitriol, which would allow lower doses of the steroid to maintain the antitumor effect while diminishing its adverse pharmacological effects.