High FOXA1 protein expression might predict late recurrence in patients with estrogen-positive and HER2-negative breast cancer

Risk factors for recurrence in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative early breast cancer in Japan: a systematic literature review and meta-analysis

BACKGROUND

The clinicopathological factors indicating risk of recurrence are used to guide the choice of perioperative therapy in patients with breast cancer. Although several risk factors for recurrence have been reported in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) early breast cancer in Japan, there has been no systematic review quantifying potential risk factors.

METHODS

We performed a systematic literature review and meta-analysis using the MEDLINE, Embase, Cochrane CENTRAL, and Japan Medical Abstract Society databases to identify risk factors for recurrence in HR+/HER2- early breast cancer in Japan. The primary outcome was relapse-free or disease-free survival (RFS/DFS), and the secondary outcomes were overall survival and breast cancer-specific survival (BCSS).

RESULTS

Searches identified 42 eligible publications. Meta-analyses identified lymph node metastasis (hazard ratio: 2.76 [95% confidence interval: 1.97-3.88]), large tumor size (1.67 [1.24-2.23]), high histological grade (1.50 [1.04-2.16]), and high nuclear grade (2.02 [1.61-2.54]) as risk factors for RFS/DFS. Lymph node metastasis (2.43 [1.28-4.63]), large tumor size (1.80 [1.24-2.62]), and high histological grade (2.02 [1.44-2.84]) were also risk factors for overall survival, and high progesterone status was a possible favorable prognostic factor for BCSS (0.20 [0.10-0.42]).

CONCLUSIONS

Identified risk factors were consistent with the previous reports, and this study provides quantitative summary of risk factors for HR+/HER2- early breast cancer recurrence in Japan. (PROSPERO Registration ID, CRD42022338391.).

FOXA1 O-GlcNAcylation-mediated transcriptional switch governs metastasis capacity in breast cancer

FOXA1, a transcription factor involved in epigenetic reprogramming, is crucial for breast cancer progression. However, the mechanisms by which FOXA1 achieves its oncogenic functions remain elusive. Here, we demonstrate that the O-linked β-N-acetylglucosamine modification (O-GlcNAcylation) of FOXA1 promotes breast cancer metastasis by orchestrating the transcription of numerous metastasis regulators. O-GlcNAcylation at Thr432, Ser441, and Ser443 regulates the stability of FOXA1 and promotes its assembly with chromatin. O-GlcNAcylation shapes the FOXA1 interactome, especially triggering the recruitment of the transcriptional repressor methyl-CpG binding protein 2 and consequently stimulating FOXA1 chromatin-binding sites to switch to chromatin loci of adhesion-related genes, including EPB41L3 and COL9A2. Site-specific depletion of O-GlcNAcylation on FOXA1 affects the expression of various downstream genes and thus inhibits breast cancer proliferation and metastasis both in vitro and in vivo. Our data establish the importance of aberrant FOXA1 O-GlcNAcylation in breast cancer progression and indicate that targeting O-GlcNAcylation is a therapeutic strategy for metastatic breast cancer.

FOXA1 in Breast Cancer: A Luminal Marker with Promising Prognostic and Predictive Impact

The present review focuses on the function of the forkhead protein FOXA1 in breast cancer (BC) in relation to steroid hormone receptors. We explored the currently available analytic approaches for FOXA1 assessment both at gene and protein levels, comparing the differences between the available techniques used for its diagnostic assessment. In addition, we elaborated on data regarding the prognostic and predictive role of this marker in BC based on several studies that evaluated its expression in relation to the outcome and/or response to therapy. FOXA1, similar to the androgen receptor (AR), may have a dual role in BC according to hormonal status. In luminal cancers, its expression contributes to a better prognosis, while in triple-negative breast cancers (TNBC), it implies an adverse outcome. Consequently, we observed that FOXA1-positive expression in a neoadjuvant setting may predict a lack of response in luminal BC as opposed to TNBC, in which FOXA1 allegedly increases its chemosensitivity. In conclusion, considering its accessible and convenient identification by immunohistochemistry, its important impact on prognosis, and its suitability to identify patients with different responses to chemotherapy, we propose that FOXA1 could be tested in routine diagnostics as an additional prognostic and predictive marker in BC.

MicroRNA-100 inhibits breast cancer cell proliferation, invasion and migration by targeting FOXA1

MicroRNAs (miRNAs/miRs) are highly conserved single-stranded small non-coding RNAs, which are involved in the physiological and pathological processes of breast cancer, and affect the prognosis of patients with breast cancer. The present study used the Gene Expression Omnibus (GEO)2R tool to detect miR-100 expression in breast cancer tissues obtained from GEO breast cancer-related datasets. Bioinformatics analysis revealed that miR-100 expression was downregulated in different stages, grades and lymph node metastasis stages of breast cancer, and patients with high miR-100 expression had a more favorable prognosis. Based on these analyses, Cell Counting Kit-8, wound healing and Transwell assays were performed, and the results demonstrated that overexpression of miR-100 inhibited the proliferation, migration and invasion of breast cancer cells. To verify the tumor-suppressive effect of miR-100 in breast cancer, the LinkedOmics and PITA databases were used to assess the association between miR-100 and forkhead box A1 (FOXA1). The results demonstrated that miR-100 had binding sites within the FOXA1 gene, and FOXA1 expression was negatively associated with miR-100 expression in breast cancer tissues. Similarly, a negative association was observed between miR-100 and FOXA1 expression, using the StarBase V3.0 database. The association between miR-100 and FOXA1 was further verified via reverse transcription-quantitative PCR and western blot analyses, and the dual-luciferase reporter assay. The results demonstrated that miR-100 targeted the 3′-untranslated region of FOXA1 in breast cancer cells. Furthermore, rescue experiments were performed to confirm whether miR-100 exerts its antitumor effects by regulating FOXA1. The results demonstrated that overexpression of FOXA1 promoted the proliferation, migration and invasion of breast cancer cells; thus, the antitumor effects of miR-100 in breast cancer were reversed following overexpression of FOXA1. Taken together, the results of the present study suggest that miR-100 inhibits the proliferation, migration and invasion of breast cancer cells by targeting FOXA1 expression. These results may provide a novel insight and an experimental basis for identifying effective therapeutic targets of high specificity for breast cancer.

FOXA1 of regulatory variant associated with risk of breast cancer through allele-specific enhancer in the Chinese population

BACKGROUND

FOXA1 is a pioneer transcription factor which has been established as a carcinogenic factor and can regulate the expression of downstream target genes in breast cancer. We hypothesized that genetic variants modulating FOXA1 expression might play a role in the risk of breast cancer.

METHODS

Physical interaction predicted by PreSTIGE analysis and CHIA-PET data integration with cis-expression quantitative trait loci (cis-eQTL) based SNP-FOXA1 analysis were used to identify potentially regulatory variants modulating the expression of FOXA1. Then, we utilized a case-control study consisting of 855 new diagnosed breast cancer cases and 920 controls in the Chinese population to identify breast cancer associated variants. Biological assays were conducted in breast cancer cell lines to illustrate the effects of associated variants on breast cancer risk.

RESULTS

We identified that rs7160774 G > A variant was associated with lower risk of breast cancer (OR = 0.77, 95% confidence interval = 0.62-0.96, P = 0.022). Biological experiments indicated that rs7160774[A] allele down-regulated the expression of FOXA1 compared to the G allele by influencing transcription factor binding affinity, thus playing an important role in the development of breast cancer.

CONCLUSION

Our study suggested that the regulatory variant rs7160774 was associated with risk of breast cancer by long-range modulating FOXA1 expression and provided critical insights into pinpoint causal genetic variants.

Genome-Wide Analysis Unveils DNA Helicase RECQ1 as a Regulator of Estrogen Response Pathway in Breast Cancer Cells

Susceptibility to breast cancer is significantly increased in individuals with germ line mutations in RECQ1 (also known as RECQL or RECQL1), a gene encoding a DNA helicase essential for genome maintenance. We previously reported that RECQ1 expression predicts clinical outcomes for sporadic breast cancer patients stratified by estrogen receptor (ER) status. Here, we utilized an unbiased integrative genomics approach to delineate a cross talk between RECQ1 and ERα, a known master regulatory transcription factor in breast cancer. We found that expression of ESR1, the gene encoding ERα, is directly activated by RECQ1. More than 35% of RECQ1 binding sites were cobound by ERα genome-wide. Mechanistically, RECQ1 cooperates with FOXA1, the pioneer transcription factor for ERα, to enhance chromatin accessibility at the ESR1 regulatory regions in a helicase activity-dependent manner. In clinical ERα-positive breast cancers treated with endocrine therapy, high RECQ1 and high FOXA1 coexpressing tumors were associated with better survival. Collectively, these results identify RECQ1 as a novel cofactor for ERα and uncover a previously unknown mechanism by which RECQ1 regulates disease-driving gene expression in ER-positive breast cancer cells.

Time-varying effects of FOXA1 on breast cancer prognosis

PURPOSE

Results of previous studies on the associations between Forkhead box A1 (FOXA1) expression in breast cancer tissues and the prognosis varied depending on the follow-up durations. The present study would investigate whether there is a time-varying effect of FOXA1 in breast cancer tissues on the prognosis.

METHODS

FOXA1 expressions were evaluated in 1041 primary invasive breast tumors with tissue microarrays by immunohistochemistry. Cox models with restricted cubic splines and Kaplan-Meier survival analysis were used to examine the associations between FOXA1 and the prognosis. Flexible parametric models were applied to explore the time-varying effect of FOXA1.

RESULTS

Overall, the association between FOXA1 expression and the prognosis was not significant but varied on the time of follow-up. Compared to FOXA1 ≤ 270 of H-score, the hazard ratios (HRs) of death for those with 271-285 of FOXA1 expression increased from 0.35 (95% CI 0.14-0.86) at 6 months after diagnosis to 2.88 (95% CI 1.35-6.15) at 120 months with a crossover at around 36 months. Similar patterns were also observed for FOXA1 > 285 of H-score and for progression free survival (PFS). Moreover, when allowed both FOXA1 and estrogen receptor (ER) to change over time in the model (considering that ER had a similar time-varying effect), these time-varying effects remained for FOXA1 on both overall survival (OS) (P < 0.01) and PFS (P = 0.01) but were attenuated for ER (P = 0.13 for OS).

CONCLUSIONS

This study revealed an independent time-varying effect of FOXA1 on breast cancer prognosis, which would provide an insight into the roles of FOXA1 as a marker of breast cancer prognosis and may help optimize the medication strategies.