Heterogeneity of BCSCs contributes to the metastatic organotropism of breast cancer

Liver tropism of ER mutant breast cancer is characterized by unique molecular changes and immune infiltration

PURPOSE

Hotspot estrogen receptor alpha (ER/ESR1) mutations are recognized as the driver for both endocrine resistance and metastasis in advanced ER-positive (ER+) breast cancer, but their contributions to metastatic organ tropism remain insufficiently understood. In this study, we aim to comprehensively profile the organotropic metastatic pattern for ESR1 mutant breast cancer.

METHODS

The organ-specific metastatic pattern of ESR1 mutant breast cancer was delineated using multi-omics data from multiple publicly available cohorts of ER+ metastatic breast cancer patients. Gene mutation/copy number variation (CNV) and differential gene expression analyses were performed to identify the genomic and transcriptomic alterations uniquely associated with ESR1 mutant liver metastasis. Upstream regulator, downstream pathway, and immune infiltration analysis were conducted for subsequent mechanistic investigations.

RESULTS

ESR1 mutation-driven liver tropism was revealed by significant differences, encompassing a higher prevalence of liver metastasis in patients with ESR1 mutant breast cancer and an enrichment of mutations in liver metastatic samples. The significant enrichment of AGO2 copy number amplifications (CNAs) and multiple gene expression changes were revealed uniquely in ESR1 mutant liver metastasis. We also unveiled alterations in downstream signaling pathways and immune infiltration, particularly an enrichment of neutrophils, suggesting potential therapeutic vulnerabilities.

CONCLUSION

Our data provide a comprehensive characterization of the behaviors and mechanisms of ESR1 mutant liver metastasis, paving the way for the development of personalized therapy to target liver metastasis for patients with ESR1 mutant breast cancer.

The emerging role and mechanism of HMGA2 in breast cancer

High mobility group AT-hook 2 (HMGA2) is a member of the non-histone chromosomal high mobility group (HMG) protein family, which participate in embryonic development and other biological processes. HMGA2 overexpression is associated with breast cancer (BC) cell growth, proliferation, metastasis, and drug resistance. Furthermore, HMGA2 expression is positively associated with poor prognosis of patients with BC, and inhibiting HMGA2 signaling can stimulate BC cell progression and metastasis. In this review, we focus on HMGA2 expression changes in BC tissues and multiple BC cell lines. Wnt/β-catenin, STAT3, CNN6, and TRAIL-R2 proteins are upstream mediators of HMGA2 that can induce BC invasion and metastasis. Moreover, microRNAs (miRNAs) can suppress BC cell growth, invasion, and metastasis by inhibiting HMGA2 expression. Furthermore, long noncoding RNAs (LncRNAs) and circular RNAs (CircRNAs) mainly regulate HMGA2 mRNA and protein expression levels by sponging miRNAs, thereby promoting BC development. Additionally, certain small molecule inhibitors can suppress BC drug resistance by reducing HMGA2 expression. Finally, we summarize findings demonstrating that HMGA2 siRNA and HMGA2 siRNA-loaded nanoliposomes can suppress BC progression and metastasis.

The intricate interplay between cancer stem cells and cell-of-origin of cancer: implications for therapeutic strategies

Background

Cancer stem cells (CSCs) have emerged as pivotal players in tumorigenesis, disease progression, and resistance to therapies.

Objective

This comprehensive review delves into the intricate relationship between CSCs and the cell-of-origin in diverse cancer types.

Design

Comprehensive review of thematically-relevant literature.

Methods

We explore the underlying molecular mechanisms that drive the conversion of normal cells into CSCs and the impact of the cell-of-origin on CSC properties, tumor initiation, and therapeutic responses. Moreover, we discuss potential therapeutic interventions targeting CSCs based on their distinct cell-of-origin characteristics.

Results

Accruing evidence suggest that the cell-of-origin, the cell type from which the tumor originates, plays a crucial role in determining the properties of CSCs and their contribution to tumor heterogeneity.

Conclusion

By providing critical insights into the complex interplay between CSCs and their cellular origins, this article aims to enhance our understanding of cancer biology and pave the way for more effective and personalized cancer treatments.

Recent advances in micro-physiological systems for investigating tumor metastasis and organotropism

Tumor metastasis involves complex processes that traditional 2D cultures and animal models struggle to fully replicate. Metastatic tumors undergo a multitude of transformations, including genetic diversification, adaptation to diverse microenvironments, and modified drug responses, contributing significantly to cancer-related mortality. Micro-physiological systems (MPS) technology emerges as a promising approach to emulate the metastatic process by integrating critical biochemical, biomechanical, and geometrical cues at a microscale. These systems are particularly advantageous simulating metastasis organotropism, the phenomenon where tumors exhibit a preference for metastasizing to particular organs. Organotropism is influenced by various factors, such as tumor cell characteristics, unique organ microenvironments, and organ-specific vascular conditions, all of which can be effectively examined using MPS. This review surveys the recent developments in MPS research from the past five years, with a specific focus on their applications in replicating tumor metastasis and organotropism. Furthermore, we discuss the current limitations in MPS-based studies of organotropism and propose strategies for more accurately replicating and analyzing the intricate aspects of organ-specific metastasis, which is pivotal in the development of targeted therapeutic approaches against metastatic cancers.

Near-infrared dye IRDye800CW-NHS coupled to Trastuzumab for near-infrared II fluorescence imaging in tumor xenograft models of HER-2-positive breast cancer

Near-infrared II fluorescent probes targeting tumors for diagnostic purposes have received much attention in recent years. In this study, a fluorescent probe for the NIR-II was constructed by using IRDye800CW-NHS fluorescent dye with Trastuzumab, which was investigated for its ability to target HER-2-positive breast cancer in xenograft mice models. This probe was compared with Trastuzumab-ICG which was synthesized using a similar structure, ICG-NHS. The results demonstrated that the IRDye800CW-NHS had significantly stronger fluorescence in the NIR-I and NIR-II than ICG-NHS in the aqueous phase. And the different metabolic modes of IRDye800CW-NHS and ICG-NHS were revealed in bioimaging experiments. IRDye800CW-NHS was mainly metabolised by the kidneys, while ICG-NHS was mainly metabolised by the liver. After coupling with Trastuzumab, Trastuzumab-800CW (TMR = 5.35 ± 0.39) not only had a stronger tumor targeting ability than Trastuzumab-ICG (TMR = 4.42 ± 0.10) based on the calculated maximum tumor muscle ratio (TMR), but also had a comparatively lower hepatic uptake and faster metabolism. Histopathology analysis proved that both fluorescent probes were non-toxic to various organ tissues. These results reveal the excellent optical properties of IRDye800CW-NHS, and the great potential of coupling with antibodies to develop fluorescent probes that will hopefully be applied to intraoperative breast cancer navigation in humans.

SEPTIN3 Promotes Progression of Triple-Negative Breast Cancer via Activating Wnt Pathway

Background

There is a lack of targeted therapies for triple-negative breast cancer (TNBC), necessitating the search for novel targets. Patients with TNBC exhibit elevated expression of neuron-specific septin-3 (SEPTIN3), leading to poor prognosis. This study aimed to investigate the modulation of SEPTIN3 expression in TNBC cells.

Methods

The relative expression levels of SEPTIN3 in TNBC tissues and cell lines were determined using Western blotting and qRT-PCR. We generated lentivirally transduced TNBC cell lines so such that SEPTIN3 was overexpressed or knocked down. Next, the effect of SEPTIN3 on the biological behavior of TNBC cells was detected using a series of functional assays, including CCK8, colony formation, scratch, and transwell assays. We monitored the tumorigenicity of SEPTIN3 overexpressed cells and performed Ki-67 immunostaining in mice. The mechanism mediated by SEPTIN3 was studied using functional enrichment analysis and Western blotting.

Results

Protein and mRNA expression levels of SEPTIN3 were observed to be increased in TNBC tissues and cell lines. SEPTIN3 knockdown reduced cell growth, invasion, and migration, whereas SEPTIN3 overexpression exerted the opposite effects. SEPTIN3 was observed to favor cell growth and tumorigenicity in vivo. In addition, SEPTIN3 promoted TNBC cell aggressiveness and proliferation via activation of the Wnt signaling pathway.

Conclusion

SEPTIN3 emerged as an oncogene that accelerates tumor progression by regulating the Wnt signaling pathway.

Chemotherapy-induced executioner caspase activation increases breast cancer malignancy through epigenetic de-repression of CDH12

Cancer relapse and metastasis are major obstacles for effective treatment. One important mechanism to eliminate cancer cells is to induce apoptosis. Activation of executioner caspases is the key step in apoptosis and was considered "a point of no return". However, in recent years, accumulating evidence has demonstrated that cells can survive executioner caspase activation in response to apoptotic stimuli through a process named anastasis. Here we show that breast cancer cells that have survived through anastasis (anastatic cells) after exposure to chemotherapeutic drugs acquire enhanced proliferation and migration. Mechanistically, cadherin 12 (CDH12) is persistently upregulated in anastatic cells and promotes breast cancer malignancy via activation of ERK and CREB. Moreover, we demonstrate that executioner caspase activation induced by chemotherapeutic drugs results in loss of DNA methylation and repressive histone modifications in the CDH12 promoter region, leading to increased CDH12 expression. Our work unveils the mechanism underlying anastasis-induced enhancement in breast cancer malignancy, offering new therapeutic targets for preventing post-chemotherapy cancer relapse and metastasis.

Cuproptosis engages in c-Myc-mediated breast cancer stemness

BACKGROUND

Intra-tumoral heterogeneity (ITH) is a distinguished hallmark of cancer, and cancer stem cells (CSCs) contribute to this malignant characteristic. Therefore, it is of great significance to investigate and even target the regulatory factors driving intra-tumoral stemness. c-Myc is a vital oncogene frequently overexpressed or amplified in various cancer types, including breast cancer. Our previous study indicated its potential association with breast cancer stem cell (BCSC) biomarkers.

METHODS

In this research, we performed immunohistochemical (IHC) staining on sixty breast cancer surgical specimens for c-Myc, CD44, CD24, CD133 and ALDH1A1. Then, we analyzed transcriptomic atlas of 1533 patients with breast cancer from public database.

RESULTS

IHC staining indicated the positive correlation between c-Myc and BCSC phenotype. Then, we used bioinformatic analysis to interrogate transcriptomics data of 1533 breast cancer specimens and identified an intriguing link among c-Myc, cancer stemness and copper-induced cell death (also known as "cuproptosis"). We screened out cuproptosis-related characteristics that predicts poor clinical outcomes and found that the pro-tumoral cuproptosis-based features were putatively enriched in MYC-targets and showed a significantly positive correlation with cancer stemness.

CONCLUSION

In addition to previous reports on its oncogenic roles, c-Myc showed significant correlation to stemness phenotype and copper-induced cell toxicity in breast cancer tissues. Moreover, transcriptomics data demonstrated that pro-tumoral cuproptosis biomarkers had putative positive association with cancer stemness. This research combined clinical samples with large-scale bioinformatic analysis, covered description and deduction, bridged classic oncogenic mechanisms to innovative opportunities, and inspired the development of copper-based nanomaterials in targeting highly heterogeneous tumors.

STAT family of transcription factors in breast cancer: Pathogenesis and therapeutic opportunities and challenges

Breast cancer is the most commonly diagnosed cancer and second-leading cause of cancer deaths in women. Breast cancer stem cells (BCSCs) promote metastasis and therapeutic resistance contributing to tumor relapse. Through activating genes important for BCSCs, transcription factors contribute to breast cancer metastasis and therapeutic resistance, including the signal transducer and activator of transcription (STAT) family of transcription factors. The STAT family consists of six major isoforms, STAT1, STAT2, STAT3, STAT4, STAT5, and STAT6. Canonical STAT signaling is activated by the binding of an extracellular ligand to a cell-surface receptor followed by STAT phosphorylation, leading to STAT nuclear translocation and transactivation of target genes. It is important to note that STAT transcription factors exhibit diverse effects in breast cancer; some are either pro- or anti-tumorigenic while others maintain dual, context-dependent roles. Among the STAT transcription factors, STAT3 is the most widely studied STAT protein in breast cancer for its critical roles in promoting BCSCs, breast cancer cell proliferation, invasion, angiogenesis, metastasis, and immune evasion. Consequently, there have been substantial efforts in developing cancer therapeutics to target breast cancer with dysregulated STAT3 signaling. In this comprehensive review, we will summarize the diverse roles that each STAT family member plays in breast cancer pathobiology, as well as, the opportunities and challenges in pharmacologically targeting STAT proteins and their upstream activators in the context of breast cancer treatment.

Advances in Biomarkers and Endogenous Regulation of Breast Cancer Stem Cells

Breast cancer is one of the most common cancers. Even if breast cancer patients initially respond to treatment, developed resistance can lead to a poor prognosis. Cancer stem cells (CSCs) are a group of undifferentiated cells with self-renewal and multipotent differentiation characteristics. Existing evidence has shown that CSCs are one of the determinants that contribute to the heterogeneity of primary tumors. The emergence of CSCs causes tumor recurrence, metastasis, and therapeutic resistance. Previous studies indicated that different stemness-associated surface markers can identify other breast cancer stem cell (BCSC) subpopulations. Deciphering the critical signaling networks that are involved in the induction and maintenance of stemness is essential to develop novel BCSC-targeting strategies. In this review, we reviewed the biomarkers of BCSCs, critical regulators of BCSCs, and the signaling networks that regulate the stemness of BCSCs.

Primary neuroendocrine carcinoma of the breast with leptomeninges metastasis: A case report and literature review

Primary neuroendocrine carcinoma of the breast (NECB) is a rare tumour with an incident rate of 0.3-0.5%. The most common metastatic sites of NECB are liver, bones, lung, pancreas, soft tissues and brain, while leptomeninges metastasis (LM) is reported rarely. This current case report describes a 50-year-old female patient with NECB and LM whose overall survival was 2 months. The report also presents the current literature regarding the knowledge of this unusual tumour and metastatic type. The current patient was diagnosed with NECB with right cerebellar metastasis, followed by LM. She underwent modified radical mastectomy of the left breast, left whole breast radiation therapy and incomplete adjuvant chemotherapy until the metastasis occurred. Whole-brain radiation therapy and a first-line salvage regimen of etoposide and cis-platinum were then undertaken. The patient died 2 months after their LM diagnosis. Primary NECB with LM is sporadic, devoid of effective treatment and associated with a poor prognosis. Consequently, it is vitally important to identify LM in order to achieve longer patient survival.

Breast Cancer Genomics: Primary and Most Common Metastases

Specific genomic alterations have been found in primary breast cancer involving driver mutations that result in tumorigenesis. Metastatic breast cancer, which is uncommon at the time of disease onset, variably impacts patients throughout the course of their disease. Both the molecular profiles and diverse genomic pathways vary in the development and progression of metastatic breast cancer. From the most common metastatic site (bone), to the rare sites such as orbital, gynecologic, or pancreatic metastases, different levels of gene expression indicate the potential involvement of numerous genes in the development and spread of breast cancer. Knowledge of these alterations can, not only help predict future disease, but also lead to advancement in breast cancer treatments. This review discusses the somatic landscape of breast primary and metastatic tumors.