Chemotherapy for Triple-Negative Breast Cancer: Is More Better?

A second-generation eIF4A RNA helicase inhibitor exploits translational reprogramming as a vulnerability in triple-negative breast cancer

In this study, we aimed to address the current limitations of therapies for macro-metastatic triple-negative breast cancer (TNBC) and provide a therapeutic lead that overcomes the high degree of heterogeneity associated with this disease. Specifically, we focused on well-documented but clinically underexploited cancer-fueling perturbations in mRNA translation as a potential therapeutic vulnerability. We therefore developed an orally bioavailable rocaglate-based molecule, MG-002, which hinders ribosome recruitment and scanning via unscheduled and non-productive RNA clamping by the eukaryotic translation initiation factor (eIF) 4A RNA helicase. We demonstrate that MG-002 potently inhibits mRNA translation and primary TNBC tumor growth without causing overt toxicity in mice. Importantly, given that metastatic spread is a major cause of mortality in TNBC, we show that MG-002 attenuates metastasis in pre-clinical models. We report on MG-002, a rocaglate that shows superior properties relative to existing eIF4A inhibitors in pre-clinical models. Our study also paves the way for future clinical trials exploring the potential of MG-002 in TNBC and other oncological indications.

Antiproliferative Effect of Inorganic and Organic Selenium Compounds in Breast Cell Lines

Triple-negative breast cancer (TNBC) is an aggressive, fast-growing tumor that is more likely to spread to distant organs. Among women diagnosed with breast cancer, the prevalence of TNBC is 20%, and treatment is currently limited to chemotherapy. Selenium (Se), an essential micronutrient, has been explored as an antiproliferative agent. Therefore, this study aimed to evaluate the effects of exposure to organic (selenomethionine, ebselen, and diphenyl diselenide) and inorganic (sodium selenate and sodium selenite) Se molecules in different breast cell lines. The compounds were tested at 1, 10, 50, and 100 μM for 48 h in the non-tumor breast cell line (MCF-10A) and TNBC derivatives cell lines (BT-549 and MDA-MB-231). The effects of Se on cell viability, apoptotic and necrotic processes, colony formation, and cell migration were analyzed. Exposure to selenomethionine and selenate did not alter the evaluated parameters. However, selenomethionine had the highest selectivity index (SI). The exposure to the highest doses of selenite, ebselen, and diphenyl diselenide resulted in antiproliferative and antimetastatic effects. Selenite had a high SI to the BT cell line; however, the SI of ebselen and diphenyl diselenide was low in both tumoral cell lines. In conclusion, the Se compounds had different effects on the breast cell lines, and additional tests are needed to reveal the antiproliferative effects of Se compounds.

The oncogenic roles and clinical implications of YAP/TAZ in breast cancer

Breast cancer (BC) is the most commonly diagnosed form of cancer and a leading cause of cancer-related deaths among women worldwide. Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are homologous transcriptional coactivators and downstream effectors of Hippo signalling. YAP/TAZ activation has been revealed to play essential roles in multiple events of BC development, including tumour initiation, progression, metastasis, drug resistance and stemness regulations. In this review, we will first give an overview of YAP/TAZ-mediated oncogenesis in BC, and then systematically summarise the oncogenic roles of YAP/TAZ in various BC subtypes, BC stem cells (BCSCs) and tumour microenvironments (TMEs). Based on these findings, we will further discuss the clinical implications of YAP/TAZ-based targeted therapies in BC and the potential future direction.

Addition of Capecitabine to Adjuvant Chemotherapy May be the Most Effective Strategy for Patients With Early-Stage Triple-Negative Breast Cancer: A Network Meta-Analysis of 9 Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

Previous studies determined the therapeutic effects of capecitabine-based chemotherapy regimens on early-stage triple-negative breast cancer (TNBC). However, the optimal strategy of capecitabine-based chemotherapy remains uncertain. We conducted this network meta-analysis to address this issue.

METHODS

We systematically searched PubMed, Embase, and the Cochrane Registry of Controlled Trials (CENTRAL) to retrieve eligible studies published before September 2021. Two independent reviewers extracted information from eligible studies using a pre-designed data extraction sheet. The primary outcome included disease-free survival, and the second outcome showed overall survival and adverse events. Direct meta-analysis was performed using RevMan 5.4, and Bayesian network analysis was performed using R version 3.6.1 with the "gemtc" and "rjags" packages.

RESULTS

Nine studies involving 3661 TNBC patients met the selection criteria. The network meta-analysis suggested that the addition of capecitabine to adjuvant chemotherapy achieved a significantly longer disease-free (HR = 0.66, 95% CrI = 0.49 to 0.86) and overall survival time (HR = 0.60, 95% CrI = 0.43 to 0.83) than standard chemotherapy. All comparisons did not achieve statistical significance. The addition of capecitabine to adjuvant chemotherapy was the most effective treatment for improving disease-free (81.24%) and overall survival (78.46%) times, and the replacement of capecitabine to adjuvant chemotherapy was the safest regime.

CONCLUSIONS

Based on available evidence, capecitabine-based chemotherapy benefits TNBC patients, and the addition of capecitabine with adjuvant chemotherapy was the most effective regime. In contrast, the replacement of capecitabine to adjuvant chemotherapy was the safest regime. More studies of high quality and large scale are needed to confirm our findings.

Recent Advancements in Mitochondria-Targeted Nanoparticle Drug Delivery for Cancer Therapy

Mitochondria are critical subcellular organelles that produce most of the adenosine triphosphate (ATP) as the energy source for most eukaryotic cells. Moreover, recent findings show that mitochondria are not only the "powerhouse" inside cells, but also excellent targets for inducing cell death via apoptosis that is mitochondria-centered. For several decades, cancer nanotherapeutics have been designed to specifically target mitochondria with several targeting moieties, and cause mitochondrial dysfunction via photodynamic, photothermal, or/and chemo therapies. These strategies have been shown to augment the killing of cancer cells in a tumor while reducing damage to its surrounding healthy tissues. Furthermore, mitochondria-targeting nanotechnologies have been demonstrated to be highly efficacious compared to non-mitochondria-targeting platforms both in vitro and in vivo for cancer therapies. Moreover, mitochondria-targeting nanotechnologies have been intelligently designed and tailored to the hypoxic and slightly acidic tumor microenvironment for improved cancer therapies. Collectively, mitochondria-targeting may be a promising strategy for the engineering of nanoparticles for drug delivery to combat cancer.

Platinum-based systematic therapy in triple-negative breast cancer

Due to the lack of definitive hormone receptors, triple negative breast cancer (TNBC) patients receive little clinical benefit from endocrine or molecular targeted therapies, leading to a highly aggressive disease with a high recurrence rate and poor prognosis. In the past decades, chemotherapy has been the mainstay of treatment for TNBC, with taxane/anthracyclines as the representative regimen. However, increasing irreversible cardiotoxicity of anthracyclines and drug-resistance had to be noticed. Gradually, platinum-based chemotherapy has become a topic of interest for researchers. Based on the accumulating studies on platinum-containing regimens for TNBC patients, we will summarize the progress of relevant clinical trials focusing on platinum monotherapy (e.g., cisplatin, carboplatin and oxaliplatin) or in combination with other therapeutic modalities (e.g., other chemotherapeutic agents, molecular targeted therapies and immunotherapy). To further evaluate patient response to platinum and screen for the optimal population to benefit from platinum, we will also analyze current potential biomarkers, such as breast cancer susceptibility genes (BRCA1/2), homologous recombination repair deficiency (HRD), tumor infiltrating lymphocytes (TILs), TP53 family and other emerging indicators (e.g., intrinsic subtype, cyclin-dependent kinase 2 (CDK2) expression, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9)).

Graphene nanoribbon-based supramolecular ensembles with dual-receptor targeting function for targeted photothermal tumor therapy

Triple negative breast cancer (TNBC) is one of the most malignant subtypes of breast cancer. Here, we report the construction of graphene nanoribbon (GNR)-based supramolecular ensembles with dual-receptor (mannose and αvβ3 integrin receptors) targeting function, denoted as GNR-Man/PRGD, for targeted photothermal treatment (PTT) of TNBC. The GNR-Man/PRGD ensembles were constructed through the solution-based self-assembly of mannose-grafted GNRs (GNR-Man) with a pyrene-tagged αvβ3 integrin ligand (PRGD). Enhanced PTT efficacies were achieved both in vitro and in vivo compared to that of the non-targeting equivalents. Tumor-bearing live mice were administered (tail vein) with GNR-Man/PRGD and then each mice group was subjected to PTT. Remarkably, GNR-Man/PRGD induced complete ablation of the solid tumors, and no tumor regrowth was observed over a period of 15 days. This study demonstrates a new and promising platform for the development of photothermal nanomaterials for targeted tumor therapy.

Optimizing cisplatin delivery to triple-negative breast cancer through novel EGFR aptamer-conjugated polymeric nanovectors

BACKGROUND

Management of triple-negative breast cancer (TNBC) is still challenging because of its aggressive clinical behavior and limited targeted treatment options. Cisplatin represents a promising chemotherapeutic compound in neoadjuvant approaches and in the metastatic setting, but its use is limited by scarce bioavailability, severe systemic side effects and drug resistance. Novel site-directed aptamer-based nanotherapeutics have the potential to overcome obstacles of chemotherapy. In this study we investigated the tumor targeting and the anti-tumorigenic effectiveness of novel cisplatin-loaded and aptamer-decorated nanosystems in TNBC.

METHODS

Nanotechnological procedures were applied to entrap cisplatin at high efficacy into polymeric nanoparticles (PNPs) that were conjugated on their surface with the epidermal growth factor receptor (EGFR) selective and cell-internalizing CL4 aptamer to improve targeted therapy. Internalization into TNBC MDA-MB-231 and BT-549 cells of aptamer-decorated PNPs, loaded with BODIPY505-515, was monitored by confocal microscopy using EGFR-depleted cells as negative control. Tumor targeting and biodistribution was evaluated by fluorescence reflectance imaging upon intravenously injection of Cyanine7-labeled nanovectors in nude mice bearing subcutaneous MDA-MB-231 tumors. Cytotoxicity of cisplatin-loaded PNPs toward TNBC cells was evaluated by MTT assay and the antitumor effect was assessed by tumor growth experiments in vivo and ex vivo analyses.

RESULTS

We demonstrate specific, high and rapid uptake into EGFR-positive TNBC cells of CL4-conjugated fluorescent PNPs which, when loaded with cisplatin, resulted considerably more cytotoxic than the free drug and nanovectors either unconjugated or conjugated with a scrambled aptamer. Importantly, animal studies showed that the CL4-equipped PNPs achieve significantly higher tumor targeting efficiency and enhanced therapeutic effects, without any signs of systemic toxicity, compared with free cisplatin and untargeted PNPs.

CONCLUSIONS

Our study proposes novel and safe drug-loaded targeted nanosystems for EGFR-positive TNBC with excellent potential for the application in cancer diagnosis and therapy.

Transport-driven engineering of liposomes for delivery of α-particle radiotherapy to solid tumors: effect on inhibition of tumor progression and onset delay of spontaneous metastases

PURPOSE

Highly cytotoxic α-particle radiotherapy delivered by tumor-selective nanocarriers is evaluated on metastatic Triple Negative Breast Cancer (TNBC). On vascularized tumors, the limited penetration of nanocarriers (<50-80 μm) combined with the short range of α-particles (40-100 μm) may, however, result in only partial tumor irradiation, compromising efficacy. Utilizing the α-particle emitter Actinium-225 (²²⁵Ac), we studied how the therapeutic potential of a general delivery strategy using nanometer-sized engineered liposomes was affected by two key transport-driven properties: (1) the release from liposomes, when in the tumor interstitium, of the highly diffusing ²²⁵Ac-DOTA that improves the uniformity of tumor irradiation by α-particles and (2) the adhesion of liposomes on the tumors' ECM that increases liposomes' time-integrated concentrations within tumors and, therefore, the tumor-delivered radioactivities.

METHODS

On an orthotopic MDA-MB-231 TNBC murine model forming spontaneous metastases, we evaluated the maximum tolerated dose (MTD), biodistributions, and control of tumor growth and/or spreading after administration of ²²⁵Ac-DOTA-encapsulating liposomes, with different combinations of the two transport-driven properties.

RESULTS

At 83% of MTD, ²²⁵Ac-DOTA-encapsulating liposomes with both properties (1) eliminated formation of spontaneous metastases and (2) best inhibited the progression of orthotopic xenografts, compared to liposomes lacking one or both properties. These findings were primarily affected by the extent of uniformity of the intratumoral microdistributions of ²²⁵Ac followed by the overall tumor uptake of radioactivity. At the MTD, long-term toxicities were not detected 9.5 months post administration.

CONCLUSION

Our findings demonstrate the potential of a general, transport-driven strategy enabling more uniform and prolonged solid tumor irradiation by α-particles without cell-specific targeting.

Adjuvant chemotherapy for small, lymph node-negative, triple-negative breast cancer: A single-center study and a meta-analysis of the published literature

BACKGROUND

Current guidelines recommend adjuvant chemotherapy for patients with small, lymph node-negative, triple-negative breast cancer (TNBC) measuring >5 mm (T1b disease), but clinical evidence to support this recommendation is lacking. Thus, the current study aimed to evaluate the survival benefit of adjuvant chemotherapy in patients with T1N0M0 (measuring ≤2 cm) TNBC with different tumor sizes.

METHODS

The authors retrospectively evaluated consecutive patients with pT1N0M0 TNBC who were diagnosed between 2000 and 2016 at Sun Yat-Sen University Cancer Center. For the meta-analysis, electronic medical databases were searched for all relevant studies regarding the effect of adjuvant chemotherapy on the target population.

RESULTS

Of the 351 enrolled patients, 309 (88%) received adjuvant chemotherapy and 42 patients (12%) did not. The distribution by T classification was T1a in 19 patients (5.4%), T1b in 67 patients (19.1%), and T1c in 265 patients (75.5%). Adjuvant chemotherapy significantly improved recurrence-free survival (RFS) in the patients with T1c disease, but not those with T1b and T1a disease. Meanwhile, there was no difference in RFS noted according to the chemotherapy regimen among patients with T1c disease. Seven eligible studies comprising 1525 patients with T1N0M0 (941 with T1a/bN0M0) were included in the meta-analysis. The meta-analysis demonstrated that adjuvant chemotherapy significantly reduced the rate of disease recurrence for patients with T1a/b disease as a group, but the population driving that was only patients with T1b disease, not those with T1a disease.

CONCLUSIONS

Although the retrospective analysis demonstrated a survival benefit of adjuvant chemotherapy only for patients with T1cN0 TNBC, the meta-analysis showed it also is beneficial for individuals with T1bN0 TNBC. For patients with T1cN0M0 TNBC, less intensive chemotherapy regimens achieve an excellent survival outcome similar to that of intensive anthracycline and taxane combination chemotherapy.

The Shuganhuazheng Formula in Triple-Negative Breast Cancer: A Study Based on Network Pharmacology and In Vivo Experiments

Breast cancer is the most common cancer in women. Among breast cancer subtypes, triple-negative breast cancer (TNBC) has the highest degree of malignancy and the worst prognosis. The Shuganhuazheng formula (SGHZF) is a traditional Chinese herbal formula for the treatment of TNBC, but the mechanism of SGHZF in the treatment of TNBC remains unclear. In this study, the therapeutic effect and mechanism of SGHZF against TNBC were preliminarily determined based on in vivo experimental verification and network pharmacology. In terms of therapeutic effects, the antitumour effect was verified by measuring and calculating tumour volume, and the expression of proto-oncogene c-Myc was verified by PCR. In terms of the mechanism, potential therapeutic targets were identified by overlapping the SGHZF-related and TNBC-related targets. After comprehensively analysing the results of the protein-protein interaction (PPI), gene ontology (GO) function, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, Akt and HIF-1α were selected for verification by using immunohistochemical and Western blot analyses. The results of the study indicated that SGHZF can inhibit breast tumour growth in mice and that the mechanism may be related to the inhibition of Akt and HIF-1α expression.

Inhibition of DOT1L by Half-Selenopsammaplin A Analogs Suppresses Tumor Growth and EMT-Mediated Metastasis in Triple-Negative Breast Cancer

Due to a lack of hormone receptors, current treatment strategies for triple-negative breast cancer (TNBC) are limited with frequent disease recurrence and metastasis. Recent findings have suggested that aberrant methylation of histone H3 lysine 79 residue (H3K79me) by the histone methyltransferase disruptor of telomeric silencing 1-like (DOT1L) is a potential therapeutic target for TNBC clinical management. Therefore, we developed DOT1L inhibitors as potential antitumor agents against TNBC cells. We reveal that a synthetic half-selenopsammaplin A analog 9l (subsequently known as 9l) exhibited inhibitory activity against DOT1L-mediated H3K79 methylation, and showed antitumor activity in TNBC cells. The analog 9l also significantly inhibited TNBC invasion and migration via the modulation of epithelial-mesenchymal transition (EMT) markers, including N-cadherin and vimentin downregulation and E-cadherin upregulation. In an MDA-MB-231/Luc-implanted orthotopic mouse metastasis model, treatment with 9l effectively inhibited tumor growth and lung metastasis via DOT1L regulatory activity and EMT processes. Taken together, these findings highlight the potential of 9l as a novel therapeutic candidate for treating metastatic TNBC via DOT1L modulation.

Mass Spectrometry-Based Omics for the Characterization of Triple-Negative Breast Cancer Bio-Signature

Triple-negative breast cancer (TNBC) represents an unmet medical need due to a high rate of metastatic occurrence and poor overall survival, pathology aggressiveness, heterogeneous clinical behavior and limited cytotoxic chemotherapy options available because of the absence of targetable receptors. The current standard of care in TNBC is represented by chemotherapy and surgery associated with low overall survival and high relapse rates. Hopes of overcoming current limited and unspecific approaches of TNBC therapy lie in studying the metabolic rewiring of these types of breast cancer, thus understanding the mechanisms involved in the occurrence and progression of the disease. Due to its heterogeneity, a clinically relevant sub-classification of this type of breast cancer based on biomarker panels is greatly needed in order to guide treatment decisions. Mass spectrometry-based omics may provide very useful tools to address the current needs of targetable biomarker discovery and validation. The present review aims to provide a comprehensive view of the current clinical diagnosis and therapy of TNBC highlighting the need for a new approach. Therefore, this paper offers a detailed mass spectrometry-based snapshot of TNBC metabolic adjustment, emphasizing a complex network of variables governing the diverse and aggressive clinical behavior of TNBC.

Targeted Heating of Mitochondria Greatly Augments Nanoparticle-Mediated Cancer Chemotherapy

Cancer is the second leading cause of mortality globally. Various nanoparticles have been developed to improve the efficacy and safety of chemotherapy, photothermal therapy, and their combination for treating cancer. However, most of the existing nanoparticles are low in both subcellular precision and drug loading content (<≈5%), and the effect of targeted heating of subcellular organelles on the enhancement of chemotherapy has not been well explored. Here, a hybrid Py@Si-TH nanoparticle is reported to first target cancer cells overexpressed with the variant CD44 via its natural ligand HA on the outermost surface of the nanoparticle before cellular uptake, and then target mitochondria after they are taken up inside cells. In addition, the nanoparticle is ultraefficient for encapsulating doxorubicin hydrochloride (DOX) to form Py@Si-TH-DOX nanoparticle. The encapsulation efficiency is ≈100% at the commonly used low feeding ratio of 1:20 (DOX:empty nanoparticle), and >80% at an ultrahigh feeding ratio of 1:1. In combination with near infrared (NIR, 808 nm) laser irradiation, the tumor weight in the Py@Si-TH-DOX treatment group is 8.5 times less than that in the Py@Si-H-DOX (i.e., DOX-laden nanoparticles without mitochondrial targeting) group, suggesting targeted heating of mitochondria is a valuable strategy for enhancing chemotherapy to combat cancer.

Albumin Nanoparticle of Paclitaxel (Abraxane) Decreases while Taxol Increases Breast Cancer Stem Cells in Treatment of Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) has a high rate of metastasis, which is associated with breast cancer stem-like cells (CSCs). Although Taxol (micelle formulation of paclitaxel) is the first line chemotherapy to treat TNBC, it increases CSCs in residual tumors. Abraxane, albumin nanoparticle of paclitaxel, showed lower plasma concentration compared to Taxol in both human and animal models, but it is not clear why Abraxane showed superior efficacy to Taxol in treatment of metastatic breast cancer in humans. In this study, we intend to investigate if Abraxane eliminates CSCs for its better efficacy. The results showed that Abraxane showed similar cytotoxicity in SUM149 cells in comparison with Taxol. Although Abraxane showed 3- to 5-fold lower blood drug concentration compared to Taxol, it achieved similar tumor drug concentration and 10-fold higher tumor/plasma ratio in SUM149 xenograft NOD/SCID mouse model. In addition, Abraxane and Taxol showed similar efficacy to shrink the tumor size in orthotopic breast cancer NOD/SCID mouse model. However, Abraxane decreased breast CSCs frequency by 3- to 9-fold, while Taxol increased breast CSCs frequency in an orthotopic breast cancer NOD/SCID mouse model. Furthermore, Abraxane increased 3- to 15-fold intracellular uptake in both ALDH+ CSCs and differentiated ALDH- cells in comparison with Taxol, which provides a mechanism for Abraxane's superior efficacy to eliminate CSCs in comparison with Taxol. Our data suggest albumin nanoparticle Abraxane may have a broad implication to enhance drug's efficacy by eliminating breast cancer stem cells for treatment of metastatic diseases.

Targeting lysyl oxidase (LOX) overcomes chemotherapy resistance in triple negative breast cancer

Chemoresistance is a major obstacle in triple negative breast cancer (TNBC), the most aggressive breast cancer subtype. Here we identify hypoxia-induced ECM re-modeler, lysyl oxidase (LOX) as a key inducer of chemoresistance by developing chemoresistant TNBC tumors in vivo and characterizing their transcriptomes by RNA-sequencing. Inhibiting LOX reduces collagen cross-linking and fibronectin assembly, increases drug penetration, and downregulates ITGA5/FN1 expression, resulting in inhibition of FAK/Src signaling, induction of apoptosis and re-sensitization to chemotherapy. Similarly, inhibiting FAK/Src results in chemosensitization. These effects are observed in 3D-cultured cell lines, tumor organoids, chemoresistant xenografts, syngeneic tumors and PDX models. Re-expressing the hypoxia-repressed miR-142-3p, which targets HIF1A, LOX and ITGA5, causes further suppression of the HIF-1α/LOX/ITGA5/FN1 axis. Notably, higher LOX, ITGA5, or FN1, or lower miR-142-3p levels are associated with shorter survival in chemotherapy-treated TNBC patients. These results provide strong pre-clinical rationale for developing and testing LOX inhibitors to overcome chemoresistance in TNBC patients.

The development of chemoresistance is a major hurdle in triple negative breast cancer (TNBC). Here, the authors show that lysyl oxidase (LOX) is overexpressed in chemoresistant TNBCs, and when inhibited reduces collagen cross-linking, fibronectin fibril assembly, and downstream integrin signalling, overcoming resistance.

Adjuvant Capecitabine With Docetaxel and Cyclophosphamide Plus Epirubicin for Triple-Negative Breast Cancer (CBCSG010): An Open-Label, Randomized, Multicenter, Phase III Trial

PURPOSE

Standard adjuvant chemotherapy for triple-negative breast cancer (TNBC) includes a taxane and an anthracycline. Concomitant capecitabine may be beneficial, but robust data to support this are lacking. The efficacy and safety of the addition of capecitabine into the TNBC adjuvant treatment regimen was evaluated.

PATIENTS AND METHODS

This randomized, open-label, phase III trial was conducted in China. Eligible female patients with early TNBC after definitive surgery were randomly assigned (1:1) to either capecitabine (3 cycles of capecitabine and docetaxel followed by 3 cycles of capecitabine, epirubicin, and cyclophosphamide) or control treatment (3 cycles of docetaxel followed by 3 cycles of fluorouracil, epirubicin, and cyclophosphamide). Randomization was centralized without stratification. The primary end point was disease-free survival (DFS).

RESULTS

Between June 2012 and December 2013, 636 patients with TNBC were screened, and 585 were randomly assigned to treatment (control, 288; capecitabine, 297). Median follow-up was 67 months. The 5-year DFS rate was higher for capecitabine than for control treatment (86.3% v 80.4%; hazard ratio, 0.66; 95% CI, 0.44 to 0.99; P = .044). Five-year overall survival rates were numerically higher but not significantly improved (capecitabine, 93.3%; control, 90.7%). Overall, 39.1% of patients had capecitabine dose reductions, and 8.4% reported grade ≥ 3 hand-foot syndrome. The most common grade ≥ 3 hematologic toxicities were neutropenia (capecitabine, 136 [45.8%]; control, 118 [41.0%]) and febrile neutropenia (capecitabine, 50 [16.8%]; control, 46 [16.0%]). Safety data were similar to the known capecitabine safety profile and generally comparable between arms.

CONCLUSION

Capecitabine when added to 3 cycles of docetaxel followed by 3 cycles of a 3-drug anthracycline combination containing capecitabine instead of fluorouracil significantly improved DFS in TNBC without new safety concerns.

FKBP12 is a predictive biomarker for efficacy of anthracycline-based chemotherapy in breast cancer

Background

FK506-binding protein 12 (FKBP12) is abundant, ubiquitously expressed cytoplasmic protein with multiple functions in cell signaling transduction. Recently, we reported a novel function for FKBP12 in oncoprotein mouse double minute 2 (MDM2) self-ubiquitination and degradation, which greatly enhanced the sensitivity of cancer cells to chemotherapy. However, the clinical relevance remains unclear.

Methods

An immunohistochemical analysis of FKBP12 expression was performed in a cohort of 524 patients with invasive breast cancer. The correlations of FKBP12 expression with patient survival and chemoresponse were statistically analyzed. MDA-MB-468 cells were transfected with FKBP12 siRNA or Myc-tagged FKBP12, and then, the tumor cells were treated with doxorubicin followed by western blot, cell viability, and apoptosis assay.

Results

The expression of FKBP12 was decreased in breast cancer tissues, and there was a significant correlation between FKBP12 loss and MDM2 overexpression. Furthermore, FKBP12 loss was specifically correlated with poor prognosis and increased resistance to anthracycline-based chemotherapy. Kaplan–Meier survival analysis showed that overall survival (OS) and disease-free survival (DFS) were both significantly lower in the low FKBP12 expression group than those in the high FKBP12 expression group. In patients treated with anthracycline-based preoperative chemotherapy, low FKBP12 expression patients had a significant lower rate of pathologic complete response (pCR). Importantly, these results seemed to be driven mainly by MDM2. These observations were especially prominent in the MDM2-positive subgroup. Univariate and multivariate analyses revealed that FKBP12 loss was an independent factor for predicting prognosis and pCR. In in vitro assay, FKBP12 silence led to significant upregulation of MDM2. Accordingly, MDA-MB-468 cells with FKBP12 silence were less responsive to doxorubicin-induced cytotoxic and apoptotic effect. In contrast, in FKBP12-transfected MDA-MB-468 cells, MDM2 was more greatly inhibited by doxorubicin, resulting in greater cytotoxic and apoptotic effect.

Conclusions

We propose that FKBP12 loss, which can be enhanced by MDM2 overexpression, predicts poor prognosis and chemoresistance. Increasing the expression of FKBP12 may be a valuable strategy to add to anthracycline-based chemotherapy, especially in MDM2-overexpressed patients.

Precise targeting of POLR2A as a therapeutic strategy for human triple negative breast cancer

TP53 is the most frequently mutated or deleted gene in triple negative breast cancer (TNBC). Both the loss of TP53 and the lack of targeted therapy are significantly correlated with poor clinical outcomes, making TNBC the only type of breast cancer that has no approved targeted therapies. Through in silico analysis, we identified POLR2A in the TP53-neighbouring region as a collateral vulnerability target in TNBC tumours, suggesting that its inhibition via small interfering RNA (siRNA) may be an amenable approach for TNBC targeted treatment. To enhance bioavailability and improve endo/lysosomal escape of siRNA, we designed pH-activated nanoparticles for augmented cytosolic delivery of POLR2A siRNA (siPol2). Suppression of POLR2A expression with the siPol2-laden nanoparticles leads to enhanced growth reduction of tumours characterized by hemizygous POLR2A loss. These results demonstrate the potential of the pH-responsive nanoparticle and the precise POLR2A targeted therapy in TNBC harbouring the common TP53 genomic alteration.

MiR-25-3p promotes the proliferation of triple negative breast cancer by targeting BTG2

Background

Triple-negative breast cancer (TNBC) is highly invasive and aggressive and lacks specific molecular targets to improve the prognosis. MiR-25-3p promotes proliferation of many tumors and its role and underlying mechanisms in TNBC remain to be well elucidated.

Methods

Differential expression of miR-25-3p in TNBC was measured with quantitative real-time PCR (qRT-PCR) in both TNBC tissues and cell lines and was validated in the Cancer Genome Atlas (TCGA) database. The effects of miR-25-3p on proliferation, apoptosis capacity of TNBC were evaluated using Cell counting kit-8 (CCK-8), colony formation assay and Annexin V-FITC/PI analyses. The tumor growth in vivo was observed in xenograft model. Luciferase reporter assay, qPCR and western blot were performed to validate a potential target of miR-25-3p in TNBC. Involvement of the AKT and MAPK pathways was investigated by western blot.

Results

MiR-25-3p was found to be upregulated in TNBC in tissues and cell lines. MiR-25-3p promoted TNBC cell proliferation in vitro and tumor growth in xenograft model, while suppression of miR-25-3p induced cell apoptosis. The luciferase reporter assay confirmed that B-cell translocation gene 2 (BTG2) might be a direct target of miR-25-3p, and its expression was negatively regulated by miR-25-3p. Moreover, inhibition of BTG2 expression accounted for the role of miR-25-3p in TNBC. Furthermore, BTG2 suppression might indirectly activate the AKT and ERK-MAPK signaling pathways to mediate the downstream effects of miR-25-3p.

Conclusions

This study demonstrates that miR-25-3p promotes proliferation by targeting tumor suppressor BTG2 and may identify new diagnostic and therapeutic targets in TNBC.

Electronic supplementary material

The online version of this article (10.1186/s12943-017-0754-0) contains supplementary material, which is available to authorized users.

Metronomic chemotherapy for non-metastatic triple negative breast cancer: Selection is the key

Triple negative breast cancer (TNBC) accounts for 15%-20% of all breast cancer, and is still defined as what it is not. Currently, TNBC is the only type of breast cancer for which there are no approved targeted therapies and maximum tolerated dose chemotherapy with taxanes and anthracycline-containing regimens is still the standard of care in both the neoadjuvant and adjuvant settings. In the last years, metronomic chemotherapy (MC) is being explored as an alternative to improve outcomes in TNBC. In the neoadjuvant setting, purely metronomic and hybrid approaches have been developed with the objective of increasing complete pathologic response (pCR) and prolonging disease free survival. These regimens proved to be very effective achieving pCR rates between 47%-60%, but at the cost of great toxicity. In the adjuvant setting, MC is used to intensify adjuvant chemotherapy and, more promisingly, as maintenance therapy for high-risk patients, especially those with no pCR after neoadjuvant chemotherapy. Considering the dismal prognosis of TNBC, any strategy that potentially improves outcomes, specially being the oral agents broadly available and inexpensive, should be considered and certainly warrants further exploration. Finally, the benefit of MC needs to be validated in properly designed clinical trials were the selection of the population is the key.

Practical Approach to Triple-Negative Breast Cancer

Triple negative is a term applied to breast cancers that do not meaningfully express the estrogen or progesterone hormone receptors or overexpress the human epidermal growth factor receptor 2 tyrosine kinase. At present, the only proven method for systemic management of triple-negative breast cancer for both early-stage and metastatic settings is cytotoxic chemotherapy. Here, we provide a comprehensive review of management strategies that are best supported by available data. We also review recent advances most likely to affect treatment of triple-negative breast cancer in the coming years with particular emphasis on targeted agents, biologics, and immunotherapy.

Metronomics in the neoadjuvant and adjuvant treatment of breast cancer

The concept of metronomic chemotherapy (MC) has evolved from a descriptive preclinical phenomenon encompassing inhibition of angiogenesis to a clinically validated treatment concept involving multiple potential mechanisms of action. Clinicians are progressively more incline to consider MC as a component of mainstream medical oncology practice in advanced breast cancer. However, more recently MC has been tested even in the adjuvant/neoadjuvant setting, taking the opportunity to obtain tumor specimens and blood samples, in order to identify tumor-specific or patient-specific biomarkers for personalizing treatments. In addition, the antiangiogenic and pro-immune nature of metronomic chemotherapy made triple negative breast cancer (TNBC) a good candidate for exploring low-dose maintenance treatment in the adjuvant setting or in combination with immunomodulatory drugs. The potential development of MC in breast cancer pass through the research to identify biomarkers and individual tumor characteristics that can better address the use of this treatment strategy in the future. Finally, the subjective attitude of patients represents one of the major factors that influence the choice and acceptance of a therapeutic program. Personal preference and considerations about quality of life should guide the treatment choice eventually prioritizing the use of MC. Nevertheless, more robust data from randomized phase III trials are needed in the future, in order to make clinicians more confident in using metronomic strategies.