p53 status identifies triple-negative breast cancer patients who do not respond to adjuvant chemotherapy

Investigation the apoptotic effect of silver nanoparticles (Ag-NPs) on MDA-MB 231 breast cancer epithelial cells via signaling pathways

Background

The discovery of novel cancer therapeutic strategies leads to the development of nanotechnology-based methods for cancer treatment. Silver nanoparticles (Ag-NPs) have garnered considerable interest owing to their size, shape, and capacity to modify chemical, optical, and photonic properties. This study aimed to investigate the impact of Ag-NPs on inducing of apoptosis in MDA-MB 231 cells by examining specific signaling pathways.

Materials and methods

The cytotoxicity of Ag-NPs was determined using an MTT assay in MDA-MB 231 cells. The apoptotic effects were assessed using the Annexin-V/PI assay. Real-time PCR and western blotting were conducted to analyze the expression of apoptosis-related genes and proteins, respectively. Levels of ERK1/2 and cyclin D1 were measured using ELISA. Cell cycle assay was determined by flow cytometry. Cell migration was evaluated by scratch assay.

Results

The results revealed that Ag-NPs triggered apoptosis and cell cycle arrest in MDA-MB 231 cells. The expression level of Bax (pro-apoptotic gene) was increased, while Bcl-2 (anti-apoptotic gene) expression was decreased. Increased apoptosis was correlated with increased levels of p53 and PTEN. Additionally, notable alterations were observed in protein expression related to the Janus kinase/Signal transducers (JAK/STAT) pathway, including p-AKT. Additionally, reduced expression of h-TERT was observed following exposure to Ag-NPs. ELISA results demonstrated a significant reduction in p-ERK/Total ERK and cyclin D1 levels in Ag-NPs-exposed MDA-MB 231 cells. Western blotting analysis also confirmed the reduction of p-ERK/Total ERK and cyclin D1. Decreased level of cyclin D is associated with suppression of cell cycle progression. The migratory ability of MDA-MB-231 cells was reduced upon treatment with Ag-NPs.

Conclusions

Our findings revealed that Ag-NPs influenced the proliferation, apoptosis, cell cycle, and migration in MDA-MB 231 cells, possibly by modulating protein expression of the AKT/ERK/Cyclin D1 axis.

A combination of novel NSC small molecule inhibitor along with doxorubicin inhibits proliferation of triple-negative breast cancer through metabolic reprogramming

Treatment of patients with triple-negative breast cancer (TNBC) has been challenging due to the absence of well-defined molecular targets and the highly invasive and proliferative nature of TNBC cells. Current treatments against TNBC have shown little promise due to high recurrence rate in patients. Consequently, there is a pressing need for novel and efficacious therapies against TNBC. Here, we report the discovery of a novel small molecule inhibitor (NSC33353) with potent anti-tumor activity against TNBC cells. The anti-proliferative effects of this small molecule inhibitor were determined using 2D and 3D cell proliferation assays. We found that NSC33353 significantly reduces the proliferation of TNBC cells in these assays. Using proteomics, next generation sequencing (NGS), and gene enrichment analysis, we investigated global regulatory pathways affected by this compound in TNBC cells. Proteomics data indicate a significant metabolic reprograming affecting both glycolytic enzymes and energy generation through oxidative phosphorylation. Subsequently, using metabolic (Seahorse) and enzymatic assays, we validated our proteomics and NGS analysis findings. Finally, we showed the inhibitory and anti-tumor effects of this small molecule in vitro and confirmed its inhibitory activity in vivo. Doxorubicin is one of the most effective agents in the treatment of TNBC and resistance to this drug has been a major problem. We show that the combination of NSC33353 and doxorubicin suppresses the growth of TNBC cells synergistically, suggesting that NSC33353 enhances TNBC sensitivity to doxorubicin. In summary, our data indicate that the small molecule inhibitor, NSC33353, exhibits anti-tumor activity in TNBC cells, and works in a synergistic fashion with a well-known chemotherapeutic agent.

Aberrant calcium signalling downstream of mutations in TP53 and the PI3K/AKT pathway genes promotes disease progression and therapy resistance in triple negative breast cancer

Triple-negative breast cancer (TNBC) is characterized as an aggressive form of breast cancer (BC) associated with poor patient outcomes. For the majority of patients, there is a lack of approved targeted therapies. Therefore, chemotherapy remains a key treatment option for these patients, but significant issues around acquired resistance limit its efficacy. Thus, TNBC has an unmet need for new targeted personalized medicine approaches. Calcium (Ca²⁺) is a ubiquitous second messenger that is known to control a range of key cellular processes by mediating signalling transduction and gene transcription. Changes in Ca²⁺ through altered calcium channel expression or activity are known to promote tumorigenesis and treatment resistance in a range of cancers including BC. Emerging evidence shows that this is mediated by Ca²⁺ modulation, supporting the function of tumour suppressor genes (TSGs) and oncogenes. This review provides insight into the underlying alterations in calcium signalling and how it plays a key role in promoting disease progression and therapy resistance in TNBC which harbours mutations in tumour protein p53 (TP53) and the PI3K/AKT pathway.

Novel microtubule inhibitor SQ overcomes multidrug resistance in MCF-7/ADR cells by inhibiting BCRP function and mediating apoptosis

The occurrence of multidrug resistance (MDR) is one of the impediments in the clinical treatment of breast cancer, and MDR breast cancer has abnormally high breast cancer resistance protein (BCRP/ABCG2) expression. However, there are currently no clinical drugs that inhibit this target. Our previous study found that 2-Methoxy-5((3,4,5-trimethosyphenyl)seleninyl) phenol (SQ0814061/SQ), a small molecule drug with low toxicity to normal tissues, could target microtubules, inhibit the proliferation of breast cancer, and reduce its migration and invasion abilities. However, the effect and the underlying mechanism of SQ on MDR breast cancers are still unknown. Therefore, in this study, we investigated the effect of SQ on adriamycin-resistant MCF-7 (MCF-7/ADR) cells and explored the underlying mechanism. The MTT assay showed that SQ had potent cytotoxicity to MCF-7/ADR cells. In particular, the results of western blot and flow cytometry proved that SQ could effectively inhibit the expression of BCRP in MCF-7/ADR cells to decrease its drug delivery activity. In addition, SQ could block the cell cycle at G2/M phase in parental and MCF-7/ADR cells, thereby mediating cell apoptosis, which was related with the inhibition of PI3K-Akt-MDM2 pathway. Taken together, our findings indicate that SQ overcomes multidrug resistance in MCF-7/ADR cells by inhibiting BCRP function and mediating apoptosis through PI3K-Akt-MDM2 pathway inhibition.

EphA8 inhibits cell apoptosis via AKT signaling and is associated with poor prognosis in breast cancer

Erythropoietin‑producing hepatocellular receptors (Ephs) comprise the largest subfamily of receptor tyrosine kinases and have been reported to be involved in a variety of biological cellular processes, including tumorigenesis and cancer progression. The present study aimed to determine the expression levels and clinicopathological significance of EphA8 in breast cancer (BC) using immunohistochemistry analysis of tissue microarrays. The results of the present study revealed that EphA8 expression levels were upregulated in BC tissue and were associated with tumor size and TNM stage. In addition, upregulated expression levels of EphA8 were identified to be a poor prognostic biomarker for patients with BC. The knockdown of EphA8 expression using short hairpin RNA resulted in increased levels of apoptosis as well as decreased proliferation, migration and invasion of BC cells both in vivo and in vitro. The knockdown of EphA8 also decreased the phosphorylation of AKT, which was accompanied by downregulation of Bcl‑2 expression levels and upregulation of p53, Caspase‑3 and Bax expression levels. Moreover, knockdown of EphA8 expression increased the chemosensitivity of BC cells to paclitaxel. In conclusion, the results of the present study indicated that EphA8 may be a useful prognostic marker in BC and that knockdown of EphA8 may represent a novel strategy in adjuvant chemotherapy for the treatment of BC.

miRNome and Functional Network Analysis of PGRMC1 Regulated miRNA Target Genes Identify Pathways and Biological Functions Associated With Triple Negative Breast Cancer

Background

Increased expression of the progesterone receptor membrane component 1, a heme and progesterone binding protein, is frequently found in triple negative breast cancer tissue. The basis for the expression of PGRMC1 and its regulation on cellular signaling mechanisms remain largely unknown. Therefore, we aim to study microRNAs that target selective genes and mechanisms that are regulated by PGRMC1 in TNBCs.

Methods

To identify altered miRNAs, whole human miRNome profiling was performed following AG-205 treatment and PGRMC1 silencing. Network analysis identified miRNA target genes while KEGG, REACTOME and Gene ontology were used to explore altered signaling pathways, biological processes, and molecular functions.

Results

KEGG term pathway analysis revealed that upregulated miRNAs target specific genes that are involved in signaling pathways that play a major role in carcinogenesis. While multiple downregulated miRNAs are known oncogenes and have been previously demonstrated to be overexpressed in a variety of cancers. Overlapping miRNA target genes associated with KEGG term pathways were identified and overexpression/amplification of these genes was observed in invasive breast carcinoma tissue from TCGA. Further, the top two genes (CCND1 and YWHAZ) which are highly genetically altered are also associated with poorer overall survival.

Conclusions

Thus, our data demonstrates that therapeutic targeting of PGRMC1 in aggressive breast cancers leads to the activation of miRNAs that target overexpressed genes and deactivation of miRNAs that have oncogenic potential.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Analysis of the radio-pathological factors of triple negative breast cancer and determination of risk profiles

OBJECTIVE

Triple-negative tumors are the most aggressive type of breast cancer. We aimed to analyze the main radiologic and histopathologic factors of these tumors to create a risk profile.

MATERIALS AND METHODS

We analyzed data from 140 patients diagnosed with triple-negative breast cancer between January 2007 and December 2016, with follow-up through April 2018. We analyzed the following variables in the breast MRI done for staging: size, necrosis, associated findings, adenopathies, and perfusion and diffusion parameters. We analyzed the following variables in histopathologic studies of biopsy specimens: histological type, Scarf-Bloom, Ki67, and p53 in the infiltrating component as well as in the in situ component. We analyzed the following variables in histopathologic studies of positive lymph nodes and surgical specimens: size, lymphovascular/perineural invasion, and microglandular adenosis. We analyzed the relation between the radiologic and histopathologic factors and recurrence and disease-free survival.

RESULTS

MRI tumor size>25mm, non-nodular enhancement, breast edema, areola-nipple complex retraction, and lymph-node involvement were associated with recurrence and lower disease-free survival. Invasive lobular carcinoma, postsurgical size>20mm, and p53<15% were also associated with recurrence and lower disease-free survival. Histologically positive lymph nodes were associated with a greater percentage of recurrence and lymphovascular invasion and with lower disease-free survival. The multivariate analysis found that the variables MRI size>25mm, non-nodular enhancement, adenopathies on MRI, and p53 expression <15% were independent predictors of lower disease-free survival.

CONCLUSIONS

In triple-negative breast tumors, factors associated with lower disease-free survival are non-nodular enhancement, size>25mm, and adenopathies on MRI, and p53 expression <15% on histopathologic study.

Profiling molecular regulators of recurrence in chemorefractory triple-negative breast cancers

Background

Approximately two thirds of patients with localized triple-negative breast cancer (TNBC) harbor residual disease (RD) after neoadjuvant chemotherapy (NAC) and have a high risk-of-recurrence. Targeted therapeutic development for TNBC is of primary significance as no targeted therapies are clinically indicated for this aggressive subset. In view of this, we conducted a comprehensive molecular analysis and correlated molecular features of chemorefractory RD tumors with recurrence for the purpose of guiding downstream therapeutic development.

Methods

We assembled DNA and RNA sequencing data from RD tumors as well as pre-operative biopsies, lymphocytic infiltrate, and survival data as part of a molecular correlative to a phase II post-neoadjuvant clinical trial. Matched somatic mutation, gene expression, and lymphocytic infiltrate were assessed before and after chemotherapy to understand how tumors evolve during chemotherapy. Kaplan-Meier survival analyses were conducted categorizing cancers with TP53 mutations by the degree of loss as well as by the copy number of a locus of 18q corresponding to the SMAD2, SMAD4, and SMAD7 genes.

Results

Analysis of matched somatic genomes pre-/post-NAC revealed chaotic acquisition of copy gains and losses including amplification of prominent oncogenes. In contrast, significant gains in deleterious point mutations and insertion/deletions were not observed. No trends between clonal evolution and recurrence were identified. Gene expression data from paired biopsies revealed enrichment of actionable regulators of stem cell-like behavior and depletion of immune signaling, which was corroborated by total lymphocytic infiltrate, but was not associated with recurrence. Novel characterization of TP53 mutation revealed prognostically relevant subgroups, which were linked to MYC-driven transcriptional amplification. Finally, somatic gains in 18q were associated with poor prognosis, likely driven by putative upregulation of TGFß signaling through the signal transducer SMAD2.

Conclusions

We conclude TNBCs are dynamic during chemotherapy, demonstrating complex plasticity in subclonal diversity, stem-like qualities, and immune depletion, but somatic alterations of TP53/MYC and TGFß signaling in RD samples are prominent drivers of recurrence, representing high-yield targets for additional interrogation.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1171-7) contains supplementary material, which is available to authorized users.

Double-positive in triple-negative? How significant is basal cytokeratin expression in breast cancer?

Background

Basal-like breast cancer has an unfavorable prognosis. Immunohistochemically, they are predominantly estrogen receptor (ER), progesterone receptor (PR) and CerbB2 receptor (HER2)-negative, show expression of Cytokeratins (CKs) 5/6, CK14, CK 17 and P-cadherin and are associated with germline BRCA1 mutations. Immunohistochemistry (IHC) is an easily available and relatively inexpensive technique that can detect this cancer subtype, and patients can benefit from aggressive management protocols. The aim of this study was to evaluate the expression of CK 5/6 and CK14 in breast cancer and its correlation with age, tumor grade, tumor size, histomorphological pattern, nodal status, ER, PR, HER2/neu, and Ki-67 index.

Methods

Fifty treatment-naїve patients of breast carcinoma who underwent surgery constituted the study group. No core cut biopsy specimens were considered. Histopathological examination along with IHC was performed for CK5/6, CK14, ER, PR, HER2/neu, and Ki-67. Comparison between the expression of CK5/6 and CK14 with age, tumor size, tumor grade, histological subtype, nodal status, ER, PR, HER2/neu, and Ki-67 expression was performed using SPSS 20 version software.

Results

Twenty-six percent of cases showed expression of CK5/6 and CK14. CK5/6 and CK14 expression correlated strongly with ER/PR negativity, young age, and Ki-67 proliferative index greater than 15%. No significant association with HER2/neu negativity was demonstrated. Contrasting results were obtained between CK5/6 and CK14 expression with respect to tumor grade and lymph node status.

Conclusion

IHC can be used to identify patients with basal phenotype breast cancer with good sensitivity and specificity, and such patients can benefit from aggressive management.

Apoptosis regulator Bcl-2 is an independent prognostic marker for worse overall survival in triple-negative breast cancer patients

BACKGROUND

The objective of this study was to examine the prognostic significance of carbonic anhydrase IX (CAIX), an endogenous marker for tumor hypoxia; the cellular tumor antigen p53; and the apoptosis regulator Bcl-2, in triple-negative breast cancer (TNBC) patients.

METHODS

Immunohistochemically determined expression of CAIX, p53, Bcl-2 and proliferation factor Ki-67, analyzed in 64 paraffin-embedded TNBC tissue samples, was used to assess their relation to clinicopathological variables and prognostic implications for overall survival (OS).

RESULTS

Bcl-2 expression was negatively correlated with histological grade of tumor, while expression of p53 was positively correlated with the same clinical variable (p = 0.036 and p = 0.033, respectively). The p53 expression was also positively correlated with tumor size (p = 0.010). Survival analysis showed that patients with high Bcl-2 expression (above cutoff value determined by receiver operator characteristic [ROC] curve analysis) had shorter OS (p = 0.020). The same was observed for patients with tumors larger than 5 cm (p = 0.034) or positive lymph nodes (p = 0.004). Among all 3 examined markers, multivariate analysis showed that only Bcl-2 expression was a strong independent prognostic indicator for decreased OS (hazard ratio [HR] = 15.16, 95% confidence interval [95% CI], 2.881-79.727, p = 0.001).

CONCLUSIONS

Elevated expression of Bcl-2 was an independent prognostic factor for poorer OS in TNBC and as such a significant marker for tumor aggressiveness.

Constitutively activated ERK sensitizes cancer cells to doxorubicin: Involvement of p53-EGFR-ERK pathway

The tumour suppressor gene p53 is mutated in approximately 50% of the human cancers. p53 is involved in genotoxic stress-induced cellular responses. The role of EGFR and ERK in DNA-damage-induced apoptosis is well known. We investigated the involvement of activation of ERK signalling as a consequence of non-functional p53, in sensitivity of cells to doxorubicin. We performed cell survival assays in cancer cell lines with varying p53 status: MCF-7 (wild-type p53, WTp53), MDA MB-468 (mutant p53, MUTp53), H1299 (absence of p53, NULLp53) and an isogenic cell line MCF-7As (WTp53 abrogated). Our results indicate that enhanced chemosensitivity of cells lacking wild-type p53 function is because of elevated levels of EGFR which activates ERK. Additionally, we noted that independent of p53 status, pERK contributes to doxorubicin-induced cell death.

Immunohistochemical Surrogates for Molecular Classification of Breast Carcinoma: A 2015 Update

CONTEXT

-The pioneering works on molecular classification (MC) by Perou and Sorlie et al in the early 2000s using global gene expression profiling identified 5 intrinsic subtypes of invasive breast cancers (IBCs): luminal A, luminal B, normal breast-like, HER2-enriched, and basal-like subtypes, each unique in incidence, survival, and response to therapy. Because the application of gene expression profiling in daily practice is not economical or practical at the present time, many investigators have studied the use of immunohistochemical (IHC) surrogates as a substitute for determining the MC of IBC.

OBJECTIVE

-To discuss the continuing efforts that have been made to develop clinically significant and readily available IHC surrogates for the MC of IBC.

DATA SOURCES

-Data were obtained from pertinent peer-reviewed English-language literature.

CONCLUSIONS

-The most commonly used IHC surrogates are estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2), dividing IBC into luminal, HER2, and triple-negative subtypes. The addition of Ki-67, cytokeratin 5, and epidermal growth factor receptor (EGFR) separates luminal B from luminal A subtypes, and basal-like subtype from triple-negative breast cancer. More recently, biomarkers such as androgen receptor and p53 have been shown to further stratify these molecular subtypes. Although many studies of IHC-based MC have shown clinical significance similar to gene expression profiling-defined MC, its critical limitations are: (1) a lack of standardization in terminology, (2) a lack of standardization in biomarkers used for each subtype, and (3) the lack of a uniform cutoff for each biomarker. A panel of IHC surrogates for each subtype of IBC is proposed.

Imaging and histologic prognostic factors in triple-negative breast cancer and carcinoma in situ as a prognostic factor

OBJECTIVES

To analyze what factors in magnetic resonance imaging (MRI) and histological study of triple-negative breast cancers are related to tumor recurrence and to shorter disease-free survival. To analyze survival and recurrence in function of the presence of an in situ component.

MATERIAL AND METHODS

This was a retrospective study of MRI staging examinations in 122 women with triple-negative breast cancer done from 2007 through 2014. In the MRI, we evaluated morphological variables (size, margins, morphology, internal signal in T2-weighted sequences) and dynamic variables (perfusion and diffusion). In the histological study, we evaluated Ki67, p53, CK5/6, nuclear grade, and Scarff-Bloom grade, as well as the presence of an in situ component and tumor grade (high grade or not high grade). We compared the variables between patients with tumor recurrence and those without, and we conducted a survival analysis.

RESULTS

Non-nodular enhancement was more common in patients with tumor recurrence (p=0.038) and was associated with shorter disease-free survival (p=0.023). Neither diffusion restriction (p=0.079) nor ki67 (p=0.052) was associated with a worse prognosis. An in situ component was detected in 44% of triple-negative tumors, and a greater proportion of patients in the group with tumor recurrence had an in situ component; however, the presence of an in situ component was not associated with shorter survival (p = 0.185).

CONCLUSION

Non-nodular enhancement was associated with a worse prognosis. Diffusion restriction, ki67, and the presence of an in situ component were not associated with shorter disease-free survival.