C2-ceramide as a cell death inducer in HC11 mouse mammary epithelial cells

AbstractPrototheca zopfiiis an alga increasingly isolated from bovine mastitis. Of the two genotypes ofP. zopfii(genotype I and II (GT-I and II)),P. zopfiiGT-II is the genotype associated with acute mastitis and decreased milk production by unknown mechanisms. The objective was to determine inflammatory and apoptotic roles ofP. zopfiiGT-II in cultured mammary epithelial cells (from cattle and mice) and murine macrophages and using a murine model of mastitis.Prototheca zopfiiGT-II (but not GT-I) invaded bovine and murine mammary epithelial cells (MECs) and induced apoptosis, as determined by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling assay. ThisP. zopfiiGT-II driven apoptosis corresponded to mitochondrial pathways; mitochondrial transmembrane resistance (ΔΨm) was altered and modulation of mitochondrion-mediated apoptosis regulating genes changed (increased transcriptionalBax, cytochrome-c andApaf-1and downregulatedBcl-2), whereas caspase-9 and -3 expression increased. Apoptotic effects byP. zopfiiGT-II were more pronounced in macrophages compared to MECs. In a murine mammary infection model,P. zopfiiGT-II replicated in the mammary gland and caused severe inflammation with infiltration of macrophages and neutrophils and upregulation of pro-inflammatory genes (TNF-α,IL-1βandCxcl-1) and also apoptosis of epithelial cells. Thus, we concludedP. zopfiiGT-II is a mastitis-causing pathogen that triggers severe inflammation and also mitochondrial apoptosis.Author summaryBovine mastitis (inflammation of the udder) reduces milk production and quality, causing huge economic losses in the dairy industry worldwide. Although the algaPrototheca zopfiiis a major cause of mastitis in dairy cows, mechanisms by which it damages mammary tissues are not well known. Here, we used cell cultures and a mouse model of mastitis to determine howProtothecacaused inflammation and cell death in mammary tissues.Protothecainvaded mammary gland cells, from cattle and mice, as well as macrophages (white cells that take up and kill pathogens) and caused cell death by interfering with mitochondria. Furthermore,Protothecacauses severe inflammation and tissue damage when injected into the mammary glands of mice. Although there are two genotypes ofP. zopfii, only genotype II causes tissue damage, whereas gentotype I, common in farm environments, does not damage mammary tissues. SinceP. zopfiiis an alga and not a bacterium, antibiotic treatments, frequently used to treat mastitis in cattle, are not effective against this organism. Understanding howP. zopfiidamages mammary tissue and causes mastitis is important new knowledge to promote future development of evidence-based approaches to prevent and treat mammary gland infections with this organism.

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TNFα redistributes ZnT2 to accumulate zinc in lysosomes and activate autophagic cell death in mammary epithelial cells

The FASEB Journal ◽

10.1096/fasebj.27.1_supplement.234.3 ◽

2013 ◽

Vol 27 (S1) ◽

Author(s):

Stephen R Hennigar ◽

Michael C Lanz ◽

Shannon L Kelleher

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Autophagic Cell Death

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Developmental regulation of Bcl-2 family protein expression in the involuting mammary gland

Journal of Cell Science ◽

10.1242/jcs.112.11.1771 ◽

1999 ◽

Vol 112 (11) ◽

pp. 1771-1783 ◽

Cited By ~ 6

Author(s):

A.D. Metcalfe ◽

A. Gilmore ◽

T. Klinowska ◽

J. Oliver ◽

A.J. Valentijn ◽

...

Keyword(s):

Cell Death ◽

Mammary Gland ◽

Epithelial Cells ◽

De Novo ◽

Mammary Epithelial Cells ◽

Expression Profiles ◽

Mammary Epithelial ◽

Mammary Tissue ◽

Pregnancy And Lactation

Epithelial cells within the mammary gland undergo developmental programmes of proliferation and apoptosis during the pregnancy cycle. After weaning, secretory epithelial cells are removed by apoptosis. To determine whether members of the Bcl-2 gene family could be involved in regulating this process, we have examined whether changes in their expression occur during this developmental apoptotic program in vivo. Bax and Bcl-x were evenly expressed throughout development. However, expression of Bak and Bad was increased during late pregnancy and lactation, and the proteins were present during the time of maximal apoptotic involution. Thereafter, their levels declined. In contrast, Bcl-w was expressed in pregnancy and lactation but was downregulated at the onset of apoptosis. Bcl-2 was not detected in lactating or early involuting mammary gland. Thus, the pro-apoptotic proteins Bax, Bak and Bad, as well as the death-suppressors Bcl-x, Bcl-2 and Bcl-w, are synthesised in mouse mammary gland, and dynamic changes in the expression profiles of these proteins occurs during development. To determine if changes in Bak and Bcl-w expression could regulate mammary apoptosis, their effect on cultured mouse mammary epithelial cells was examined in transient transfection assays. Enforced expression of Bak induced rapid mammary apoptosis, which could be suppressed by coexpression of Bcl-w. In extracts of mammary tissue in vivo, Bak heterodimerized with Bcl-x whereas Bax associated with Bcl-w, but Bak/Bcl-w heterodimers were not detected. Thus, Bak and Bcl-w may regulate cell death through independent pathways. These results support a model in which mammary epithelial cells are primed for apoptosis during the transition from pregnancy to lactation by de novo expression of the death effectors Bak and Bad. It is suggested that these proteins are prevented from triggering apoptosis by anti-apoptotic Bcl-2 family proteins until involution, when the levels of Bcl-w decline. Our study provides evidence that regulated changes in the expression of cell death genes may contribute to the developmental control of mammary apoptosis.

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JS-K, a nitric oxide-releasing prodrug, induces breast cancer cell death while sparing normal mammary epithelial cells

International Journal of Oncology ◽

10.3892/ijo.2011.925 ◽

2011 ◽

Vol 38 (4) ◽

Cited By ~ 3

Author(s):

Tari

Keyword(s):

Breast Cancer ◽

Nitric Oxide ◽

Cell Death ◽

Epithelial Cells ◽

Breast Cancer Cell ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Cancer Cell Death ◽

Nitric Oxide Releasing ◽

Normal Mammary Epithelial

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Breast-Specific Epigenetic Regulation of DeltaNp73 and Its Role in DNA-Damage-Response of BRCA1-Mutated Human Mammary Epithelial Cells

Cancers ◽

10.3390/cancers12092367 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2367

Author(s):

Ayelet Avraham ◽

Susanna Feldman ◽

Sean Soonweng Cho ◽

Ayala Kol ◽

Lior Heler ◽

...

Keyword(s):

Dna Damage ◽

Cell Death ◽

High Risk ◽

Epithelial Cell ◽

Epithelial Cells ◽

Mammary Epithelial Cells ◽

Brca1 Mutation ◽

Cell Types ◽

Mammary Epithelial ◽

Human Mammary Epithelial

The function of BRCA1/2 proteins is essential for maintaining genomic integrity in all cell types. However, why women who carry deleterious germline mutations in BRCA face an extremely high risk of developing breast and ovarian cancers specifically has remained an enigma. We propose that breast-specific epigenetic modifications, which regulate tissue differentiation, could team up with BRCA deficiency and affect tissue susceptibility to cancer. In earlier work, we compared genome-wide methylation profiles of various normal epithelial tissues and identified breast-specific methylated gene promoter regions. Here, we focused on deltaNp73, the truncated isoform of p73, which possesses antiapoptotic and pro-oncogenic functions. We showed that the promoter of deltaNp73 is unmethylated in normal human breast epithelium and methylated in various other normal epithelial tissues and cell types. Accordingly, deltaNp73 was markedly induced by DNA damage in human mammary epithelial cells (HMECs) but not in other epithelial cell types. Moreover, the induction of deltaNp73 protected HMECs from DNA damage-induced cell death, and this effect was more substantial in HMECs from BRCA1 mutation carriers. Notably, when BRCA1 was knocked down in MCF10A, a non-malignant breast epithelial cell line, both deltaNp73 induction and its protective effect from cell death were augmented upon DNA damage. Interestingly, deltaNp73 induction also resulted in inhibition of BRCA1 and BRCA2 expression following DNA damage. In conclusion, breast-specific induction of deltaNp73 promotes survival of BRCA1-deficient mammary epithelial cells upon DNA damage. This might result in the accumulation of genomic alterations and allow the outgrowth of breast cancers. These findings indicate deltaNp73 as a potential modifier of breast cancer susceptibility in BRCA1 mutation carriers and may stimulate novel strategies of prevention and treatment for these high-risk women.

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