Estrogen receptors and extracellular matrix: the critical interplay in cancer development and progression

Mimicking the Complexity of Solid Tumors: How Spheroids Could Advance Cancer Preclinical Transformative Approaches

Traditional 2D cell culture models present significant limitations in replicating the intricate architecture and microenvironment of in vivo solid tumors, which are essential for accurately studying cancer initiation, growth, progression, and metastasis. This underscores the need for the development of advanced preclinical models to accelerate research outcomes. Emerging 3D cell culture systems, particularly spheroid models, provide a more realistic representation of solid tumor properties by capturing the complex interactions occurring within the tumor microenvironment, including the extracellular matrix dynamics that influence cancer progression. Among solid tumors, breast cancer remains the most frequently diagnosed cancer among women globally and a leading cause of cancer-related mortality. Here we emphasize the value of breast cancer cell-derived spheroids in revealing differential molecular characteristics and understanding cancer cell properties during the early stages of invasion into adjacent tissues. Conclusively, this study underscores the urgent need to adopt 3D cell culture platforms, given their significant contributions to advanced cancer research and pharmaceutical targeting. This may well offer a transformative approach for preclinical studies and enhance our ability to test therapeutic efficiency in conditions that closely mimic the growth and progression of in vivo solid tumors.

Harnessing the Role of ESR1 in Breast Cancer: Correlation with microRNA, lncRNA, and Methylation

Breast cancer (BC) is a multifactorial condition and it primarily expresses the estrogen receptor α (ERα) that is encoded by the gene estrogen receptor 1 (ESR1), which modulates estrogen signaling. ESR1, by facilitating estrogen overproduction, plays an indispensable role in the progression and survival of the majority of BCs. To obtain molecular insights into these phenomena, we analyzed The Cancer Genome Atlas (TCGA) breast invasive carcinoma (BRCA) RNA-Seq datasets for the expression of ESR1 and its correlation to microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), along with its methylation patterns. Regulation of ESR1 was also assessed with a total of 43 cancerous and non-cancerous breast cell lines. Analyses of both TCGA BRCA and breast cell line RNA-Seq data revealed that specific lncRNAs, i.e., MEG3, BIK, MLL, and FAS are negatively correlated with the ESR1, in which PARP1 demonstrates a positive association. Additionally, both miR-30a and miR-145 showed negative correlations with the ESR1 expression. Of the 54 ESR1 methylation loci analyzed, the majority of them exhibited a negative correlation with the ESR1 expression, highlighting a potentially modifiable regulatory mechanism. These findings underscore the complex regulatory events influencing ESR1 expression and its interaction with diverse signaling pathways, demonstrating novel insights into breast pathogenesis and its potential therapeutics.

Simulated Galactic Cosmic Radiation Exposure-Induced Mammary Tumorigenesis in ApcMin/+ Mice Coincides with Activation of ERα-ERRα-SPP1 Signaling Axis

BACKGROUND

Exposure to galactic cosmic radiation (GCR) is a breast cancer risk factor for female astronauts on deep-space missions. However, the specific signaling mechanisms driving GCR-induced breast cancer have not yet been determined.

METHODS

This study aimed to investigate the role of the estrogen-induced ERα-ERRα-SPP1 signaling axis in relation to mammary tumorigenesis in female ApcMin/+ mice exposed to simulated GCR (GCRsim) at 100-110 days post-exposure.

RESULTS

In GCRsim-exposed mice, we observed marked elevations in serum estradiol, increased ductal overgrowth, ERα activation, and upregulation of ERα target genes with pro-tumorigenic functions in mammary tissues that was coupled with a higher mammary tumorigenesis, relative to control. Additionally, the ERα target gene Esrra, which encodes ERRα, was also upregulated along with its oncogenic target gene Spp1, indicating the activation of the ERα-ERRα-SPP1 axis in mouse mammary tissues after GCRsim exposure. Using a human tissue microarray and human breast cancer gene expression analysis, we also highlighted the conserved nature of the ERα-ERRα-SPP1 signaling in human breast cancer development.

CONCLUSIONS

We identified the ERα-ERRα-SPP1 signaling axis as a potential key mediator in GCR-induced breast cancer with conserved activation in human breast cancer. These findings suggest that targeting this pathway could serve as a potential target for therapeutic intervention to safeguard female astronauts during and after a prolonged outer space mission.