Our previous data illustrated that activation of the canonical Wnt signaling pathway was enriched in triple-negative breast cancer and associated with reduced overall survival in all patients. To ...determine whether Wnt signaling may be a promising therapeutic target for triple-negative breast cancer, we investigated whether β-catenin was necessary for tumorigenic behaviors in vivo and in vitro. β-catenin expression level was significantly reduced in two human triple-negative breast cancer cell lines, MDA-MB-231 and HCC38, using lentiviral delivery of β-catenin-specific small hairpin RNAs (shRNAs). Upon implantation of the cells in the mammary fat pad of immunocompromised mice, we found that β-catenin shRNA HCC38 cells formed markedly smaller tumors than control cells and grew much more slowly. In in vitro assays, β-catenin silencing significantly reduced the percentage of Aldefluor-positive cells, a read-out of the stem-like cell population, as well as the expression of stem cell-related target genes including Bmi-1 and c-Myc. β-catenin-knockdown cells were also significantly impaired in their ability to migrate in wound-filling assays and form anchorage-independent colonies in soft agar. β-catenin-knockdown cells were more sensitive to chemotherapeutic agents doxorubicin and cisplatin. Collectively, these data suggest that β-catenin is required for triple-negative breast cancer development by controlling numerous tumor-associated properties, such as migration, stemness, anchorage-independent growth and chemosensitivity.
Background
Genomic assays such as Oncotype Dx (ODX) and MammaPrint are used for risk‐adapted treatment decisions among patients with early breast cancer. However, to the authors' knowledge, ...concordance between genomic assays is modest. Using real‐world data, the authors performed a comparative analysis of ODX and MammaPrint.
Methods
A cohort of women diagnosed with early‐stage, hormone receptor–positive breast cancer who received ODX or MammaPrint was established using the National Cancer Data Base (NCDB) for 2010 through 2016. Using the propensity score matching method, 2 groups of patients with similar clinical and demographic characteristics were defined: one group received ODX and the other received MammaPrint. The authors examined the association between use of the ODX or MammaPrint assays and overall survival using Cox models.
Results
Of the 451,693 eligible patients, approximately 45.3% received ODX and 1.8% received MammaPrint testing. The use of ODX increased from 36.1% in 2010 to 49.9% in 2016, whereas use of MammaPrint increased from 0.5% in 2010 to 3.3% in 2016. The authors matched 5042 patients who received ODX with 5042 patients who received MammaPrint. The 5‐year risks of death for the MammaPrint low‐risk group and the ODX low‐risk group were 3.4% and 4.7%, respectively. The prognostic value of MammaPrint was similar to that of ODX; the C‐index was 0.614 (95% confidence interval, 0.572‐0.657) for MammaPrint and 0.581 (95% confidence interval, 0.530‐0.631) for ODX. There was a difference in the performance of the ODX assay observed across racial and/or ethnic groups (P < .001), with a slightly better performance noted among white compared with African American and Hispanic individuals.
Conclusions
Both the ODX and MammaPrint tests are good at identifying low‐risk individuals who could be spared chemotherapy. The suboptimal performance of ODX in ethnic minority individuals deserves further investigation.
The findings of the current study will inform clinicians regarding the prognostic comparison between 2 genomic assays that are widely used in clinical practice. In addition, the current study also emphasizes the need to understand the tumor biology underlying racial and/or ethnic disparities in the era of precision medicine.
The contribution of BRCA germline mutational status to breast cancer patients' prognosis is unclear. We aimed to systematically review and perform meta-analysis of the available evidence of effects ...of BRCA germline mutations on multiple survival outcomes of breast cancer patients as a whole and in specific subgroups of interest, including those with triple negative breast cancer, those with Ashkenazi Jewish ancestry, and patients with stage I-III disease.
Sixty studies met all inclusion criteria and were considered for this meta-analysis. These studies involved 105,220 breast cancer patients, whose 3588 (3.4%) were BRCA mutations carriers. The associations between BRCA genes mutational status and overall survival (OS), breast cancer-specific survival (BCSS), recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) were evaluated using random-effect models.
BRCA1 mutation carriers have worse OS than BRCA-negative/sporadic cases (hazard ratio, HR 1.30, 95% CI: 1.11-1.52) and worse BCSS than sporadic/BRCA-negative cases among patients with stage I-III breast cancer (HR 1.45, 95% CI: 1.01-2.07). BRCA2 mutation carriers have worse BCSS than sporadic/BRCA-negative cases (HR 1.29, 95% CI: 1.03-1.62), although they have similar OS. Among triple negative breast cancer, BRCA1/2 mutations carriers had better OS than BRCA-negative counterpart (HR 0.49, 95% CI: 0.26-0.92). Among Ashkenazi Jewish women, BRCA1/2 mutations carriers presented higher risk of death from breast cancer (HR 1.44, 95% CI: 1.05-1.97) and of distant metastases (HR 1.82, 95% CI: 1.05-3.16) than sporadic/BRCA-negative patients.
Our results support the evaluation of BRCA mutational status in patients with high risk of harboring BRCA germline mutations to better define the prognosis of breast cancer in these patients.
The Cancer Genome Atlas (TCGA) is one of the largest biorepositories of digital histology. Deep learning (DL) models have been trained on TCGA to predict numerous features directly from histology, ...including survival, gene expression patterns, and driver mutations. However, we demonstrate that these features vary substantially across tissue submitting sites in TCGA for over 3,000 patients with six cancer subtypes. Additionally, we show that histologic image differences between submitting sites can easily be identified with DL. Site detection remains possible despite commonly used color normalization and augmentation methods, and we quantify the image characteristics constituting this site-specific digital histology signature. We demonstrate that these site-specific signatures lead to biased accuracy for prediction of features including survival, genomic mutations, and tumor stage. Furthermore, ethnicity can also be inferred from site-specific signatures, which must be accounted for to ensure equitable application of DL. These site-specific signatures can lead to overoptimistic estimates of model performance, and we propose a quadratic programming method that abrogates this bias by ensuring models are not trained and validated on samples from the same site.
Treatment of advanced breast cancer remains challenging. Copper and some of the copper-dependent proteins are emerging therapeutic targets because they are essential for cell proliferation and ...survival, and have been shown to stimulate angiogenesis and metastasis. Here, we show that DCAC50, a recently developed small-molecule inhibitor of the intracellular copper chaperones, ATOX1 and CCS, reduces cell proliferation and elevates oxidative stress, triggering apoptosis in a panel of triple-negative breast cancer (TNBC) cells. Inhibition of ATOX1 activity with DCAC50 disrupts copper homeostasis, leading to increased copper levels, altered spatial copper redistribution, and accumulation of ATP7B to the cellular perinuclear region. The extent and impact of this disruption to copper homeostasis vary across cell lines and correlate with cellular baseline copper and glutathione levels. Ultimately, treatment with DCAC50 attenuates tumor growth and suppresses angiogenesis in a xenograft mouse model, and prevents endothelial cell network formation
Co-treatment with paclitaxel and DCAC50 enhances cytotoxicity in TNBC and results in favorable dose reduction of both drugs. These data demonstrate that inhibition of intracellular copper transport targets tumor cells and the tumor microenvironment, and is a promising approach to treat breast cancer.
Precision oncology has been successful in targeting oncogenes but therapies for cancers driven by tumor suppressor loss are much more of a challenge Yes, the classic divide between a tumor suppressor ...and an oncogene persists but regulatory networks are interconnected, and the more tools we have to probe these perturbations, the more therapeutic options we open. ...immunotherapy is more successful in tumors that have abundant neoantigens likely to arise from deficient DNA repair, such as upon loss of BRCA1, something that we were able to fully understand by combining genome sequencing – both germline and cancer – with lab research. In a recent plenary lecture, you talked about studying breast cancer risk variants in Black women, a population that the health system in the US continuously underserves. Because African Americans are still distrusting the medical establishment, for valid reasons, we need community engagement to explain how genetics can work for their benefit.
Hypoxic tumor microenvironment and maintenance of stemness contribute to drug resistance in breast cancer. However, whether Hypoxia-inducible factor-2α (HIF-2α) in hypoxic tumor microenvironment ...mediates conversion to a stem cell phenotype and chemoresistance of breast tumors has not been elucidated.
The mRNA and protein expressions of HIF-1α, HIF-2α, Wnt and Notch pathway were determined using qRT-PCR and western blot. Cell viability and renew ability were assessed by MTT, Flow cytometric analysis and soft agar colony formation.
In our study, acute hypoxia (6-12 h) briefly increased HIF-1α expression, while chronic hypoxia (48 h) continuously enhanced HIF-2α expression and induced the resistance of breast cancer cells to Paclitaxel (PTX). Furthermore, HIF-2α overexpression induced a stem cell phenotype, the resistance to PTX and enhanced protein expression of stem cell markers, c-Myc, OCT4 and Nanog. Most importantly, Wnt and Notch signaling, but not including Shh, pathways were both activated by HIF-2α overexpression. Dickkopf-1 (DKK-1), a Wnt pathway inhibitor, and L685,458, an inhibitor of the Notch pathway, reversed the resistance to PTX and stem phenotype conversion induced by HIF-2α overexpression. In addition, HIF-2α overexpression enhanced tumorigenicity and resistance of xenograft tumors to PTX, increased activation of the Wnt and Notch pathways and induced a stem cell phenotype in vivo.
In conclusion, HIF-2α promoted stem phenotype conversion and induced resistance to PTX by activating Wnt and Notch pathways.
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