Dissecting the Origin of Breast Cancer Subtype Stem Cell and the Potential Mechanism of Malignant Transformation

Fetal Alcohol Exposure Alters Mammary Epithelial Cell Subpopulations and Promotes Tumorigenesis

BACKGROUND

Fetal alcohol exposure (FAE) increases the risk of mammary tumorigenesis in adult offspring; however, the underlying mechanism remains unknown. This study tested the hypothesis that FAE shifts the mammary epithelial cell (MEC) composition toward one that promotes tumorigenesis.

METHODS

Pregnant Friend Virus B NIH Jackson dams bred to MMTV-Wnt1 male mice were given ad libitum access to 5% alcohol in 0.2% saccharin solution from GD9-10 and 10% alcohol in 0.2% saccharin from GD11-GD19 or 0.2% saccharin solution from GD9-GD19. Thoracic and inguinal mammary glands from wild-type (WT) and transgenic (Tg) female offspring were harvested at 5 and 10 weeks of age and dissociated to yield a single cell suspension enriched for MECs for flow cytometry, mammosphere assay, and gene analysis. A subset of Tg offspring was followed for tumor formation.

RESULTS

WT glands of FAE animals exhibited a decreased basal cell population and increased luminal: basal ratio at 10 weeks of age. qRT-PCR analysis of total MECs found that Hey1 mRNA expression was increased in the WT FAE group at 10 weeks of age. In Tg glands, FAE increased the luminal progenitor cell population at 5 weeks of age but did not alter MEC composition at 10 weeks of age. Tertiary mammosphere-forming efficiency was greater in the WT glands of FAE animals at 10 weeks of age. Tumor latency was decreased in the FAE group. Flow cytometry analysis indicated that FAE females developed tumors with an increased basal cell population.

CONCLUSIONS

These data indicate that FAE can shift MEC subpopulations, increasing the proportion of cells that are potentially vulnerable to transformation and affecting cancer risk.

Concise Reviews: Cancer Stem Cell Targeted Therapies: Toward Clinical Success

Cancer stem cells (CSCs) are a subpopulation of cells within tumors that possess the stem cell characteristics of self-renewal, quiescence, differentiation, and the ability to recapitulate the parental tumor when transplanted into a host. CSCs are correlated with poor clinical outcome due to their contribution to chemotherapy resistance and metastasis. Multiple cell surface and enzymatic markers have been characterized to identify CSCs within a heterogeneous tumor, and here we summarize ongoing preclinical and clinical efforts to therapeutically target these cells and improve patient outcomes. Stem Cells Translational Medicine 2019;8:75-81.

Notch and Wnt Dysregulation and Its Relevance for Breast Cancer and Tumor Initiation

Breast cancer is the second leading cause of cancer deaths among women in the world. Treatment has been improved and, in combination with early detection, this has resulted in reduced mortality rates. Further improvement in therapy development is however warranted. This will be particularly important for certain sub-classes of breast cancer, such as triple-negative breast cancer, where currently no specific therapies are available. An important therapy development focus emerges from the notion that dysregulation of two major signaling pathways, Notch and Wnt signaling, are major drivers for breast cancer development. In this review, we discuss recent insights into the Notch and Wnt signaling pathways and into how they act synergistically both in normal development and cancer. We also discuss how dysregulation of the two pathways contributes to breast cancer and strategies to develop novel breast cancer therapies starting from a Notch and Wnt dysregulation perspective.

Targeting Stemness: Implications for Precision Medicine in Breast Cancer

The genomic landscape of breast cancer has been delineated in recent years. Advances in molecular characterization and targeting strategies are making it feasible to integrate clinical, genome-based and phenotype-based diagnostic and therapeutic methods and apply them to individual patient in the era of precision medicine. Cancer stem cells (CSCs) are a subpopulation in the tumor which have the capability of self-renewal and differentiation. Breast CSCs have important clinical implications as they account for tumor initiation, maintenance, metastasis, therapy resistance, and relapse. In this chapter, we will introduce approaches used to characterize breast CSCs, crucial pathways involved in regulating cancer stemness, and implications of breast CSCs in the precision diagnosis and treatment of breast cancer. We will also discuss novel compounds and therapeutic strategies that selectively target breast CSCs. Integration of breast CSC-related molecular diagnosis and targeted therapy into the clinical workflow of precision medicine has the potential to deliver more effective treatment to breast cancer patients.

Targeting tumor microenvironment to curb chemoresistance via novel drug delivery strategies

INTRODUCTION

Tumor is a heterogeneous mass of malignant cells co-existing with non-malignant cells. This co-existence evolves from the initial developmental stages of the tumor and is one of the hallmarks of cancer providing a protumorigenic niche known as tumor microenvironment (TME). Proliferation, invasiveness, metastatic potential and maintenance of stemness through cross-talk between tumors and its stroma forms the basis of TME.

AREAS COVERED

The article highlights the developmental phases of a tumor from dysplasia to the formation of clinically detectable tumors. The authors discuss the mechanistic stages involved in the formation of TME and its contribution in tumor outgrowth and chemoresistance. The authors have reviewed various approaches for targeting TME and its hallmarks along with their advantages and pitfalls. The authors also highlight cancer stem cells (CSCs) that are resistant to chemotherapeutics and thus a primary reason for tumor recurrence thereby, posing a challenge for the oncologists.

EXPERT OPINION

Recent understanding of the cellular and molecular mechanisms involved in acquired chemoresistance has enabled scientists to target the tumor niche and TME and modulate and/or disrupt this communication leading to the transformation from a tumor-supportive niche environment to a tumor-non-supporting environment and give synergistic results towards an effective management of cancer.

FGF8 promotes cell proliferation and resistance to EGFR inhibitors via upregulation of EGFR in human hepatocellular carcinoma cells

Fibroblast growth factor 8 (FGF8), a member of the fibroblast growth factor (FGF) family, is upregulated in several human cancers, including HCC (HCC). Previous studies have demonstrated that FGF8 increased cell growth and invasion of tumor cells. In the present study we investigated whether FGF8 is involved in the cell proliferation and resistance to several drugs in human HCC cells. We stably overexpressed FGF8 by lentiviral transfection. In addition, we also added recombinant FGF8 instead of stably overexpressing FGF8 in human HCC cells. Stable overexpression of FGF8 or exogenous recombinant FGF8 resulted in significantly enhanced cell proliferation in human HCC cells. With the use of CellTiter-Glo assay for the determination of cell viability, we found that FGF8 increased the resistance to epidermal growth factor receptor (EGFR) inhibitors in human HCC cells. Additionally, the expression of EGFR was also upregulated by stably overexpressing FGF8 or exogenous recombinant FGF8. Yes-associated protein 1 (YAP1) was reported to upregulate the expression of EGFR. Moreover, we also found that FGF8 increased the expression of YAP1 and knockdown of YAP1 eliminated the upregulation of EGFR and the resistance to EGFR inhibition induced by FGF8. Our study provides evidence that FGF8 plays an important role in the resistance to EGFR inhibition of human HCC cells.

Breast cancer and Flammer syndrome: any symptoms in common for prediction, prevention and personalised medical approach?

An epidemic scale of the breast cancer (BC) prevalence is actually recognised as the reality of the early twenty-first century. Particularly alarming is that the sporadic BC (about 90% of all patients) creates currently unpredictable subpopulations in terms of disease predisposition, development and progression. Despite broad discussions run since years in BC area, no any plausible approach has been suggested so far to get the overall situation better controlled in the populations. Here, we present highly innovative concepts considering investigation of specific syndromes and symptoms underestimated till now in relationship with BC predisposition and development. Consequently, the purpose of our pilot project was to evaluate the prevalence of Flammer Syndrome (FS) in BC patient cohort. The results achieved here support the main hypothesis of the project clearly demonstrating the tendency of BC patients to the increased prevalence of FS symptoms compared to the disease-free individuals. Our study strongly indicates the relevance of FS symptoms for BC pathology such as feeling inadequately cold, deficient thermoregulation, altered sensitivity to different stimuli, potential dehydration, altered sleep patterns, tendency towards headache, migraine attacks and dizziness. Moreover, the symptoms' appearance is specifically linked to the individual BC subtypes. Potential mechanisms interconnecting FS with BC pathology are discussed.

Feeling cold and other underestimated symptoms in breast cancer: anecdotes or individual profiles for advanced patient stratification?

Breast cancer (BC) epidemic is recognised as being characteristic for the early twenty-first century. BC is a multifactorial disease, and a spectrum of modifiable (preventable) factors significantly increasing risks has been described. This article highlights a series of underestimated symptoms for consequent BC risk assessment and patient stratification. Phenomena of the deficient thermoregulation, altered sensitivity to different stimuli (pain, thirst, smell, light, stress provocation), dehydration, altered circadian and sleep patterns, tendency towards headache, migraine attacks and dizziness, as well as local and systemic hypoxic effects are discussed for BC patients providing functional links and proposing new approaches in the overall BC management.