Current Management Strategies in Breast Cancer by Targeting Key Altered Molecular Players

In Vivo Chemosuppressive Effects of Kolaviron on 7,12-Dimethylbenzanthracene-Induced Mammary Lesions are Associated with Changes in Levels of Estrogen Receptor-α, CYP 1A1, Proinflammatory Cytokines, and Alterations to Metabolic Pathways Implicated in Mammary Carcinogenesis

Garcinia kola is a medicinal food commonly consumed in Sub-Sahara Africa, for which Kolaviron (KV) is the active portion. As a follow-up to our earlier chemopreventive studies, we investigated the chemotherapeutic effects of KV on experimentally induced mammary carcinogenesis in female Wistar rats. Mammary carcinogenesis was induced using 80 mg/kg of 7,12-dimethylbenzanthracene (DMBA) administered by oral gavage. One hundred-fifty days post-DMBA induction, estrogen receptor-α (ER-α) levels were determined in the experimental rats before treatment with KV commenced. Treatment was done using 50, 100, and 200 mg/kg KV thrice a week for 4 weeks, after which the experiment was terminated. Significantly higher levels of estrogen receptor-α, CYP 1A1, malondialdehyde, formation of lobular neoplastic cells, epithelial hyperplasia, lymphocyte infiltration, and increased cytokine (interleukin-6 and tumor necrosis factor-α) activity were observed in DMBA-induced rats, which were attenuated in KV-treated rats. Tyrosine metabolism was exclusively enriched in DMBA-induced rats in contrast to KV-treated rats. Collectively, the results point to the chemotherapeutic potential of KV.

siRNA treatment targeting integrin α11 overexpressed via EZH2-driven axis inhibits drug-resistant breast cancer progression

BACKGROUND

Breast cancer, the most prevalent cancer in women worldwide, faces treatment challenges due to drug resistance, posing a serious threat to patient survival. The present study aimed to identify the key molecules that drive drug resistance and aggressiveness in breast cancer cells and validate them as therapeutic targets.

METHODS

Transcriptome microarray and analysis using PANTHER pathway and StemChecker were performed to identify the most significantly expressed genes in tamoxifen-resistant and adriamycin-resistant MCF-7 breast cancer cells. Clinical relevance of the key genes was determined using Kaplan-Meier survival analyses on The Cancer Genome Atlas dataset of breast cancer patients. Gene overexpression/knockdown, spheroid formation, flow cytometric analysis, chromatin immunoprecipitation, immunocytochemistry, wound healing/transwell migration assays, and cancer stem cell transcription factor activation profiling array were used to elucidate the regulatory mechanism of integrin α11 expression. Tumour-bearing xenograft models were used to demonstrate integrin α11 is a potential therapeutic target.

RESULTS

Integrin α11 was consistently upregulated in drug-resistant breast cancer cells, and its silencing inhibited cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) while restoring sensitivity to anticancer drugs. HIF1α, GLI-1, and EZH2 contributed the most to the regulation of integrin α11 and EZH2 expression, with EZH2 being more necessary for EZH2 autoinduction than HIF1α and GLI-1. Additionally, unlike HIF1α or EZH2, GLI-1 was the sole transcription factor activated by integrin-linked focal adhesion kinase, indicating GLI-1 as a key driver of the EZH2-integrin α11 axis operating for cancer stem cell survival and EMT. Kaplan-Meier survival analysis using The Cancer Genome Atlas (TCGA) dataset also revealed both EZH2 and integrin α11 could be strong prognostic factors of relapse-free and overall survival in breast cancer patients. However, the superior efficacy of integrin α11 siRNA therapy over EZH2 siRNA treatment was demonstrated by enhanced inhibition of tumour growth and prolonged survival in murine models bearing tumours.

CONCLUSION

Our findings elucidate that integrin α11 is upregulated by EZH2, forming a positive feedback circuit involving FAK-GLI-1 and contributing to drug resistance, cancer stem cell survival and EMT. Taken together, the results suggest integrin α11 as a promising prognostic marker and a powerful therapeutic target for drug-resistant breast cancer.

Functionalized liposomes for targeted breast cancer drug delivery

Despite the exceptional progress in breast cancer pathogenesis, prognosis, diagnosis, and treatment strategies, it remains a prominent cause of female mortality worldwide. Additionally, although chemotherapies are effective, they are associated with critical limitations, most notably their lack of specificity resulting in systemic toxicity and the eventual development of multi-drug resistance (MDR) cancer cells. Liposomes have proven to be an invaluable drug delivery system but of the multitudes of liposomal systems developed every year only a few have been approved for clinical use, none of which employ active targeting. In this review, we summarize the most recent strategies in development for actively targeted liposomal drug delivery systems for surface, transmembrane and internal cell receptors, enzymes, direct cell targeting and dual-targeting of breast cancer and breast cancer-associated cells, e.g., cancer stem cells, cells associated with the tumor microenvironment, etc.

Significance of Nuclear Factor-Kappa B (NF-κB) and Survivin in Breast Cancer and Their Association with Radiosensitivity and Prognosis

Purpose

Analyze the expression of NF-κB and survivin genes and mRNAs in breast cancer, and evaluate their impact on prognosis. Investigate their association with radiosensitivity in breast cancer.

Methods

The expression levels of NF-κB and survivin genes in breast cancer were analyzed by bioinformatics, NF-κB and survivin mRNA was verified by RTRCR, and their association with prognosis were assessed. Knockdown of survivin by siRNA was used to analyze its association with radiosensitivity in breast cancer.

Results

The gene expression of NFKB1 and BIRC5 are differentially expressed in a variety of tumours and their corresponding normal tissue species. In breast cancer tissues, NFKB1 expression levels were reduced compared to normal tissue, while BIRC5 expression levels were increased (P<0.05). In different molecular subtypes of breast cancer, NFKB1 and BIRC5 were differentially expressed (P<0.05), NFKB1 was highly expressed in the luminal subtype and BIRC5 was highly expressed in the TNBC subtype. In TNBC subtype, NFKB1 expression is higher in IM subtype than other subtypes (P<0.05), and BIRC5 expression is higher in BL-2 than other subtypes (P<0.05). NFKB1 was not associated with tumour size, lymph node stage and distant metastasis (P≥0.05), while BRIC5 was associated with these clinical features (P<0.05). NF-κB and survivin genes were negatively correlated (R = - 0.193, P<0.05). The mRNA levels of NF-κB and survivin are expressed in the same trend in breast cancer patients. NF-κB and survivin were not significantly different in recurrent and non-recurrent patients (P≥0.05). The mRNA levels of the both were not correlated with breast cancer subtypes (P≥0.05). The mRNA expression of NF-κB and survivin correlated with distant metastasis. NF-κB and survivin mRNAs were positively correlated (R=0.903, P<0.05). Gene and mRNA expression of NF-κB and survivin were not associated with patients' survival overall survival (OS) (P≥0.05). Down-regulation of survivin has little effect on the proliferation rate of breast cancer cells (P≥0.05), but increase the apoptosis rate of breast cancer cells (P<0.05).The proliferation rate of cells decreased and the apoptosis rate increased significantly (P<0.05) after the implementation of radiotherapy, and this technique could improve the radiosensitivity of breast cancer cells.

Conclusion

NF-κB and survivin interact at the gene and mRNA levels. Regulation of mRNA expression of NF-κB or survivin may help to improve the radiosensitivity of breast cancer cells, more experiments are needed to verify this in the future.

Multimodal MRI examination of structural and functional brain changes in older women with breast cancer in the first year of antiestrogen hormonal therapy

PURPOSE

Cancer patients are concerned about treatment-related cognitive problems. We examined effects of antiestrogen hormonal therapy on brain imaging metrics in older women with breast cancer.

METHODS

Women aged 60 + treated with hormonal therapy only and matched non-cancer controls (n = 29/group) completed MRI and objective and self-reported cognitive assessment at pre-treatment/enrollment and 12 months later. Gray matter was examined using voxel-based morphometry (VBM), FreeSurfer, and brain age calculations. Functional MRI (fMRI) assessed working memory-related activation. Analyses examined cross-sectional and longitudinal differences and tested associations between brain metrics, cognition, and days on hormonal therapy.

RESULTS

The cancer group showed regional reductions over 12 months in frontal, temporal, and parietal gray matter on VBM, reduced FreeSurfer cortical thickness in prefrontal, parietal, and insular regions, and increased working memory-related fMRI activation in frontal, cingulate, and visual association cortex. Controls showed only reductions in fusiform gyrus on VBM and FreeSurfer temporal and parietal cortex thickness. Women with breast cancer showed higher estimated brain age and lower regional gray matter volume than controls at both time points. The cancer group showed a trend toward lower performance in attention, processing speed, and executive function at follow-up. There were no significant associations between brain imaging metrics and cognition or days on hormonal therapy.

CONCLUSION

Older women with breast cancer showed brain changes in the first year of hormonal therapy. Increased brain activation during working memory processing may be a sign of functional compensation for treatment-related structural changes. This hypothesis should be tested in larger samples over longer time periods.

CLINICALTRIALS

GOV IDENTIFIER

NCT03451383.

Knockdown of ATG4A inhibits breast cancer progression and promotes tamoxifen chemosensitivity by suppressing autophagy

Autophagy-related 4A (ATG4A) is an autophagy regulator. The current study investigated the role of ATG4A in the development of tamoxifen-resistant breast cancer. ATG4A expression was assessed in tumor and adjacent normal tissue obtained from The Cancer Genome Atlas database. Analyses of the disease-free survival between the ATG4A high and low expression groups was then evaluated in patients with breast cancer. Cell viability and apoptosis in MCF7/R cells was detected using Cell Counting Kit-8 assay and flow cytometry, respectively. Gene set enrichment analysis identified the pathway responsible for the effects of ATG4A. The protein expression of ATG4A, LC3, p62, Bcl-2, Bax, GSK-3β, phosphorylated (p)-GSK-3β, β-catenin, cyclinD1 and c-myc in MCF and MCF7/R cells was determined using western blot. In this study, ATG4A expression was increased in the tumor tissues, and a higher ATG4A expression exhibited poor disease-free survival. While 4-hydroxytamoxifen (4-OHT) increased ATG4A expression in MCF7 and MCF7/R cells, ATG4A expression decreased in the cells treated with 3-methyladenine (3MA). Treatment with 4-OHT and rapamycin (an autophagy activator) increased the LC3-II/LC3-I ratio, LC3 puncta number and decreased the level of p62 in MCF7/R cells. However, the effects of 4-OHT and rapamycin were reversed by 3MA and knockdown of ATG4A, respectively. After treatment with 4-OHT, knockdown of ATG4A suppressed proliferation, triggered apoptosis, decreased the expression of Bcl-2, β-catenin, cyclin D1 and c-myc, and increased the expression of Bax and p-GSK3β in MCF7/R cells. Moreover, SKL2001, an activator of the Wnt/β-catenin signaling pathway, reversed the effects of ATG4A knockdown on cell viability and apoptosis in MCF7/R cells. In conclusion, the knockdown of ATG4A inhibited the anticancer effects of 4-OHT in breast cancer.

A systematic review of datasets that can help elucidate relationships among gene expression, race, and immunohistochemistry-defined subtypes in breast cancer

Scholarly requirements have led to a massive increase of transcriptomic data in the public domain, with millions of samples available for secondary research. We identified gene-expression datasets representing 10,214 breast-cancer patients in public databases. We focused on datasets that included patient metadata on race and/or immunohistochemistry (IHC) profiling of the ER, PR, and HER-2 proteins. This review provides a summary of these datasets and describes findings from 32 research articles associated with the datasets. These studies have helped to elucidate relationships between IHC, race, and/or treatment options, as well as relationships between IHC status and the breast-cancer intrinsic subtypes. We have also identified broad themes across the analysis methodologies used in these studies, including breast cancer subtyping, deriving predictive biomarkers, identifying differentially expressed genes, and optimizing data processing. Finally, we discuss limitations of prior work and recommend future directions for reusing these datasets in secondary analyses.

Progress in the Understanding of the Mechanism of Tamoxifen Resistance in Breast Cancer

Tamoxifen is a drug commonly used in the treatment of breast cancer, especially for postmenopausal patients. However, its efficacy is limited by the development of drug resistance. Downregulation of estrogen receptor alpha (ERα) is an important mechanism of tamoxifen resistance. In recent years, with progress in research into the protective autophagy of drug-resistant cells and cell cycle regulators, major breakthroughs have been made in research on tamoxifen resistance. For a better understanding of the mechanism of tamoxifen resistance, protective autophagy, cell cycle regulators, and some transcription factors and enzymes regulating the expression of the estrogen receptor are summarized in this review. In addition, recent progress in reducing resistance to tamoxifen is reviewed. Finally, we discuss the possible research directions into tamoxifen resistance in the future to provide assistance for the clinical treatment of breast cancer.

Downregulation of CXXC Finger Protein 4 Leads to a Tamoxifen-resistant Phenotype in Breast Cancer Cells Through Activation of the Wnt/β-catenin Pathway

Tamoxifen is a successful endocrine therapy drug for estrogen receptor-positive (ER+) breast cancer. However, resistance to tamoxifen compromises the efficacy of endocrine treatment. In the present study, we identified potential tamoxifen resistance-related gene markers and investigated their mechanistic details. First, we established two ER + breast cancer cell lines resistant to tamoxifen, named MCF-7/TMR and BT474/TMR. Gene expression profiling showed that CXXC finger protein 4 (CXXC4) expression is lower in MCF-7/TMR cells than in MCF-7 cells. Furthermore, CXXC4 mRNA and protein expression are lower in the resistant cell lines than in the corresponding parental cell lines. We also investigated the correlation between CXXC4 and endocrine resistance in ER + breast cancer cells. CXXC4 knockdown accelerates cell proliferation in vitro and in vivo and renders breast cancer cells insensitive to tamoxifen, whereas CXXC4 overexpression inhibits cancer cell growth and increases tamoxifen sensitivity of resistant cells. In addition, we demonstrated that CXXC4 inhibits Wnt/β-catenin signaling in cancer cells by modulating the phosphorylation of GSK-3β, influencing the integrity of the β-catenin degradation complex. Silencing the CXXC4 gene upregulates expression of cyclinD1 and c-myc (the downstream targets of Wnt signaling) and promotes cell cycle progression. Conversely, ectopic expression of CXXC4 downregulates the expression of these proteins and arrests the cell cycle in the G0/G1 phase. Finally, the small-molecule inhibitor XAV939 suppresses Wnt signaling and sensitizes resistant cells to tamoxifen. These results indicate that components of Wnt pathway that are early in response to tamoxifen could be involved as an intrinsic factor of the transition to endocrine resistance, and inhibition of Wnt signaling may be an effective therapeutic strategy to overcome tamoxifen resistance.

Cytokine profile of CD4+CD25-FoxP3+ T cells in tumor-draining lymph nodes from patients with breast cancer

BACKGROUND

A T cell subtype with the CD4+CD25-FoxP3+ phenotype was recently described. We aimed to investigate the frequency of these cells and their ability to produce cytokines in tumor-draining lymph nodes from patients with breast cancer (BC).

MATERIALS AND METHODS

Mononuclear cells from lymph nodes of 20 patients with BC were activated and stained for appropriate markers. The cells were assayed with four-color flow cytometry.

RESULTS

A very small fraction of CD4+CD25-FoxP3+ cells produced cytokines at levels that were significantly lower than in the regulatory (CD4+CD25+FoxP3+) and effector cell (CD4+CD25+FoxP3-) subpopulations. The expression of IFNγ and IL-2 in the CD4+CD25-FoxP3+ subset was significantly higher than in Treg cells, but lower than in the effector subset. Conversely, IL-22 expression in Treg cells was significantly higher than in the CD4+CD25-FoxP3+ subpopulation. The expression of IL-10 in the CD4+CD25-FoxP3+ subset was also significantly higher than in effector cells.

CONCLUSION

We suggest that CD4+CD25-FoxP3+ cells in patients with BC are exhausted cells with an intermediate phenotype between effector and regulatory cells.

hERG1 channel expression associates with molecular subtypes and prognosis in breast cancer

Background

Breast cancer (BC) is the most frequent malignancy among females worldwide. Despite several efforts and improvements in early diagnosis and treatment, there are still tumors characterized by an aggressive behavior due to unfavorable biology, thus quite difficult to treat. In this view, searching for novel potential biomarkers is mandatory. Among them, in the recent years data have been gathered addressing ion channel as important players in oncology.

Methods

A retrospective pilot study was performed on 40 BC samples by means of immunohistochemistry in order to evaluate hERG1 potassium channels expression in BC.

Results

We provide evidence that hERG1 is expressed in all the BC samples analyzed. hERG1 expression was significantly associated with molecular subtype with the highest expression in Luminal A and the lowest in basal-like tumors (p = 0.001), tumor grading (the highest hERG1 expression in well-moderate differentiated tumors, p = 0.020), estrogen receptors (high hERG1 expression in ER-positive samples, p = 0.008) and Ki67 proliferative index (high hERG1 scoring in samples with low proliferative index, p = 0.038). Also, a p value close to significance was noticed for the association between hERG1 and HER2 expression (p = 0.079). At the survival analysis, patients with high hERG1 expression turned out to have a longer progression-free survival, although statistical significance was not reached (p = 0.195). The same trend was observed analyzing local relapse free-survival (LRFS) and metastases-free survival (MFS): patients with higher hERG1 scoring had longer LRFS and MFS (p = 0.124 and p = 0.071, respectively).

Conclusions

The results of this pilot study provide the first evidence that the hERG1 protein is expressed in primary BC, and its expression associates with molecular subtype. hERG1 apparently behaves as a protective factor, since it contributes to identify a subset of patients with better outcome. Overall, these data suggest that hERG1 might be an additional tool for the management of BC, nevertheless further investigations are warranted to better clarify hERG1 role and clinical usefulness in BC.

High serum uric acid concentration predicts poor survival in patients with breast cancer

BACKGROUND

Uric acid is a product of purine metabolism. Recently, uric acid has gained much attraction in cancer. In this study, we aim to investigate the clinicopathological and prognostic significance of serum uric acid concentration in breast cancer patients.

METHODS

A total of 443 female patients with histopathologically diagnosed breast cancer were included. After a mean follow-up time of 56months, survival was analysed using the Kaplan-Meier method. To further evaluate the prognostic significance of uric acid concentrations, univariate and multivariate Cox regression analyses were applied.

RESULTS

Of the clinicopathological parameters, uric acid concentration was associated with age, body mass index, ER status and PR status. Univariate analysis identified that patients with increased uric acid concentration had a significantly inferior overall survival (HR 2.13, 95% CI 1.15-3.94, p=0.016). In multivariate analysis, we found that high uric acid concentration is an independent prognostic factor predicting death, but insufficient to predict local relapse or distant metastasis. Kaplan-Meier analysis indicated that high uric acid concentration is related to the poor overall survival (p=0.013).

CONCLUSIONS

High uric acid concentration predicts poor survival in patients with breast cancer, and might serve as a potential marker for appropriate management of breast cancer patients.

MicroRNAs and Their Impact on Breast Cancer, the Tumor Microenvironment, and Disparities

Breast cancer is a worldwide health issue as it represents the leading cause of cancer in women and the second-leading cause of cancer-related mortality in women, with an increasing incidence. Nothing speaks more clearly to the shocking breast cancer health disparities than the fact that African American (AA) women are as likely to get breast cancer as Caucasian American (CA) women, yet have a higher breast cancer death rate. It is becoming increasingly apparent that racial disparity in cancer exists due to molecular differences in tumor biology as well as, or in addition to, socioeconomic and standard of care issues (Albain, Unger, Crowley, Coltman, & Hershman, 2009). A greater understanding of the risk factors and biological links associated with breast cancer, will significantly impact AA communities due to the higher deaths associated with this disease in this population. microRNAs are small noncoding RNA molecules that were recently discovered as major players in the regulation of many diseases including cancer. Although, there are many studies that have investigated the role of miRNAs in breast cancer, few have investigated their role if any in breast cancer disparities. This review serves to summarize the current published literature that is involved in the study of microRNAs and their impact on breast cancer disparities.

Molecular mechanisms and mode of tamoxifen resistance in breast cancer

Breast cancer is one of the most common cancers in women around the globe Tamoxifen is used for the last 40 years as an endocrine therapy for breast cancer. This resulted in the reduction of mortality rate by 30% and it still remains one of the most effective therapies against breast cancer. However, resistance against tamoxifen is still one of the major hurdles in the effective management of breast cancer. Intense research has been conducted in the past decade to further explore its resistance mechanism, but still a lot of research will be needed to effectively alleviate this problem. Several biochemical factors and molecular pathways, such as the modulation of ER signaling, upregulation of growth factors had been observed as key factors for tamoxifen resistance (TR). After, initial therapy of five to ten years, breast cancer patients develops resistance towards this drug. The resistance leads to the development of other cancers like uterine cancer. Here, we briefly explore all the molecular events related to tamoxifen resistance and focus on its mechanism of action as well as other pharmacological approaches to better its beneficial effects in the treatment of breast carcinoma.