In breast tumors, activation of the nuclear factor B (NFB) pathway promotes survival, migration, invasion, angiogenesis, stem cell-like properties, and resistance to therapy-all phenotypes of aggressive disease where therapy options remain limited. Adding an anti-inflammatory/anti-NFB agent to breast cancer treatment would be beneficial, but no such drug is approved as either a monotherapy or adjuvant therapy. To address this need, we examined whether dimethyl fumarate (DMF), an anti-inflammatory drug already in clinical use for multiple sclerosis, can inhibit the NFB pathway. We found that DMF effectively blocks NFB activity in multiple breast cancer cell lines and abrogates NFB-dependent mammosphere formation, indicating that DMF has anti-cancer stem cell properties. In addition, DMF inhibits cell proliferation and significantly impairs xenograft tumor growth. Mechanistically, DMF prevents p65 nuclear translocation and attenuates its DNA binding activity but has no effect on upstream proteins in the NFB pathway. Dimethyl succinate, the inactive analog of DMF that lacks the electrophilic double bond of fumarate, is unable to inhibit NFB activity. Also, the cell-permeable thiol N-acetyl L-cysteine, reverses DMF inhibition of the NFB pathway, supporting the notion that the electrophile, DMF, acts via covalent modification. To determine whether DMF interacts directly with p65, we synthesized and used a novel chemical probe of DMF by incorporating an alkyne functionality and found that DMF covalently modifies p65, with cysteine 38 being essential for the activity of DMF. These results establish DMF as an NFB inhibitor with anti-tumor activity that may add therapeutic value in the treatment of aggressive breast cancers.In the United States, breast cancer is the second most prevalent cancer among women and claims over 40,000 lives each year. Despite major advancements in breast cancer treatment, a successful therapy outcome is limited to early detection of cancer at the primary organ. Therapy options for aggressive breast cancer disease (i.e. advanced stage, therapy-resistant, recurrent, or metastatic) are limited. As a result, the prognosis remains poor, and aggressive disease accounts for more than 90% of breast cancer-related deaths.Although the underlying mechanisms are not fully understood, inflammation has emerged as a key instigator and driver of aggressive breast cancers (1, 2). More specifically, the nuclear factor B (NFB) 2 pathway promotes multiple aggressive tumor phenotypes, including cell survival, migration, invasion, angiogenesis, and resistance to therapy (3, 4). The link between the inflammatory NFB pathway and breast cancer is also supported by the fact that a deregulated, or constitutively active, NFB pathway is associated with aggressive breast cancer phenotypes and therapy resistance (5-9). More recently, activation of the NFB pathway has been shown to regulate the survival and propagation of breast cancer stem cells (CSCs) (10 -12), which are a small subset of tumor cells that evade all standar...

Background:Previous studies have uncovered heightened prostatic susceptibility to hormone-induced neoplasia from early-life exposure to low-dose bisphenol A (BPA). However, significant data gaps remain that are essential to address for biological relevance and necessary risk assessment.Objectives:A complete BPA dose–response analysis of prostate lesions across multiple prostatic lobes was conducted that included internal BPA dosimetry, progression to adenocarcinoma with aging and mechanistic connections to epigenetically reprogramed genes.Methods:Male neonatal Sprague-Dawley rats were briefly exposed to 0.1 to 5,000μg BPA/kg BW on postnatal days (PND) 1, 3, and 5. Individual prostate lobes plus periurethral prostatic ducts were evaluated at 7 mo or 1 y of age without or with adult testosterone plus estradiol (T+E) to promote carcinogenesis. DNA methylation of five genes was quantified by bisulfite genomic sequencing in d-200 dorsal prostates across BPA doses. Serum free-BPA and BPA-glucuronide were quantitated in sera of individual PND 3 pups collected 1 hr postexposure utilizing ultra-high-pressure tandem mass spectrometry (UHPLC-MS-MS).Results:The lowest BPA dose initiated maximal hormonal carcinogenesis in lateral prostates despite undetectable free BPA 1 hr postexposure. Further, prostatic intraepithelial neoplasia (PIN) progressed to carcinoma in rats given neonatal low-dose BPA with adult T+E but not in rats given adult T+E alone. The dorsal and ventral lobes and periurethral prostatic ducts exhibited a nonmonotonic dose response with peak PIN, proliferation and apoptotic values at 10–100μg/kg BW. This was paralleled by nonmonotonic and dose-specific DNA hypomethylation of genes that confer carcinogenic risk, with greatest hypomethylation at the lowest BPA doses.Conclusions:Developmental BPA exposures heighten prostate cancer susceptibility in a complex dose- and lobe-specific manner. Importantly, elevated carcinogenic risk is found at doses that yield undetectable serum free BPA. Dose-specific epigenetic modifications of selected genes provide a mechanistic framework that may connect early-life BPA to later-life predisposition to prostate carcinogenesis. https://doi.org/10.1289/EHP1050

Studies using rodent and adult human prostate stem-progenitor cell models suggest that developmental exposure to the endocrine disruptor Bisphenol-A (BPA) can predispose to prostate carcinogenesis with aging. Unknown at present is whether the embryonic human prostate is equally susceptible to BPA during its natural developmental window. To address this unmet need, we herein report the construction of a pioneer in vitro human prostate developmental model to study the effects of BPA. The directed differentiation of human embryonic stem cells (hESC) into prostatic organoids in a spatial system was accomplished with precise temporal control of growth factors and steroids. Activin-induced definitive endoderm was driven to prostate specification by combined exposure to WNT10B and FGF10. Matrigel culture for 20–30 days in medium containing R-Spondin-1, Noggin, EGF, retinoic acid and testosterone was sufficient for mature prostate organoid development. Immunofluorescence and gene expression analysis confirmed that organoids exhibited cytodifferentiation and functional properties of the human prostate. Exposure to 1 nM or 10 nM BPA throughout differentiation culture disturbed early morphogenesis in a dose-dependent manner with 1 nM BPA increasing and 10 nM BPA reducing the number of branched structures formed. While differentiation of branched structures to mature organoids seemed largely unaffected by BPA exposure, the stem-like cell population increased, appearing as focal stem cell nests that have not properly entered lineage commitment rather than the rare isolated stem cells found in normally differentiated structures. These findings provide the first direct evidence that low-dose BPA exposure targets hESC and perturbs morphogenesis as the embryonic cells differentiate towards human prostate organoids, suggesting that the developing human prostate may be susceptible to disruption by in utero BPA exposures.

High grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy in women worldwide and the fifth most common cause of cancer related deaths among U.S. women. New therapies are needed to treat HGSOC particularly since most patients develop resistance to current frontline therapies. Many natural product and fungal metabolites exhibit anti-cancer activity and represent an untapped reservoir of potential new agents with unique mechanism(s) of action. Verticillin A, an epipolythiodioxopiperazine (ETP) alkaloid, is one such compound and our recent advances in fermentation and isolation are now enabling evaluation of its anti-cancer activity. Verticillin A demonstrated cytotoxicity in HGSOC cell lines in a dose-dependent manner with a low nM IC 50 . Furthermore, treatment with verticillin A induced DNA damage and caused apoptosis in HGSOC cell lines OVCAR4 and OVCAR8. RNA-Seq analysis of verticillin A treated OVCAR8 cells revealed an enrichment of transcripts in the apoptosis signaling and the oxidative stress response pathways. Mass spectrometry histone profiling confirmed reports that verticillin A caused epigenetic modifications with global changes in histone methylation and acetylation marks. To facilitate in vivo delivery of verticillin A and to monitor its ability to reduce HGSOC tumor burden, verticillin A was encapsulated into an expansile nanoparticle (verticillin A-eNP) delivery system. In an in vivo human ovarian cancer xenograft model, verticillin A-eNPs decreased tumor *

Major advances during the past decade have permitted a clearer understanding of processes that regulate stem cell self-renewal and lineage commitment toward differentiated progeny that populate all tissues. Considerable evidence has also accumulated to indicate that aberrations in the stem and progenitor cell populations can lead to increased cancer risk in specific organs systems. It is long recognized that environmental factors play a major role in cancer etiology, and emerging data suggest that endocrine-disrupting chemicals (EDCs) may contribute to an increased cancer risk. Using the prostate gland as a model system, the present review highlights recent data that find that estrogens and EDCs can reprogram prostate stem and progenitor cell populations, leading to increased cancer susceptibility. We propose that stem cell programming during early development in hormone-regulated tissues may lead to heightened sensitivity to early-life EDC exposures and that aberrant stem cell reprogramming by EDCs may contribute to the developmental basis of adult cancer risk.

Despite major advances in breast cancer treatment, successful therapy outcome is limited to early detection of cancer at the primary organ. Therapy options for aggressive, advanced stage, metastatic and recurring cancers are limited and this translates to poor patient outcome contributing to over 40,000 deaths each year in the United States. A key underlying factor of aggressive breast cancers is activation of the inflammatory nuclear factor κB (NFκB) pathway because it promotes numerous phenotypes such as cell survival, migration, invasion, angiogenesis, stem cell-like properties, and resistance to therapy. Therefore, adding an anti-inflammatory/anti-NFκB agent to breast cancer treatment would be beneficial, but no such drug is approved as either a mono- or adjuvant therapy. One option is Tecfidera® (dimethyl fumarate, DMF), the anti-inflammatory drug already in clinical use for multiple schlerosis. DMF is neuroprotective and is proposed to act via inhibition of the NFκB and activation of Nrf2 pathway. Most importantly, DMF has a proven safety in humans. This makes DMF an attractive candidate for NFκB inhibition in breast cancer therapy. Moreover, its therapeutic potential in treating breast cancer has yet to be explored. We find that DMF inhibits proliferation of breast cancer cells in vitro. In addition, DMF abrogates mammosphere formation, a functional measure of cancer stem cell (CSC) properties. This prompted us to examine its activity in a murine breast cancer xenograft model. We find that DMF (30mg/kg daily) significantly impairs MDA-MB-231 tumor growth in athymic nude mice. As an anti-inflammatory agent, we show that DMF effectively blocks NFκB activity in multiple breast cancer cell lines. Mechanistically, DMF prevents p65 nuclear translocation and attenuates its DNA binding activity, but has no effect on upstream proteins in the NFκB pathway. Dimethyl succinate, the inactive analog of DMF that lacks the electrophilic double bond of fumarate, is unable to inhibit NFκB activity. Also, the cell permeable thiol, N-acetyl L-cysteine, reverses DMF's inhibition of the NFκB pathway, supporting the notion that the electrophile, DMF, acts via covalent modification. To determine whether DMF directly interacts with p65, we synthesized and used a novel chemical probe of DMF by incorporating an alkyne functionality, and found that DMF covalently modifies p65 at the cysteine 38 residue. Altogether, these results establish DMF as a safe and effective NFκB inhibitor in breast cancer cells and elucidate its mechanism of action. These in addition to DMF's anti-tumor activity support the advancement of DMF as a therapeutic option to treat aggressive breast cancers in the clinic. Citation Format: Irida Kastrati, Marton I. Siklos, Esther L. Calderon-Gierszal, Gregory R. J. Thatcher, Jonna Frasor. Dimethyl fumarate impairs breast cancer growth and inhibits the nuclear factor κB pathway in breast cancer cells by covalent modification of p65. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4716.

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<div>Abstract<p>High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy in women worldwide and the fifth most common cause of cancer-related deaths among U.S. women. New therapies are needed to treat HGSOC, particularly because most patients develop resistance to current first-line therapies. Many natural product and fungal metabolites exhibit anticancer activity and represent an untapped reservoir of potential new agents with unique mechanism(s) of action. Verticillin A, an epipolythiodioxopiperazine alkaloid, is one such compound, and our recent advances in fermentation and isolation are now enabling evaluation of its anticancer activity. Verticillin A demonstrated cytotoxicity in HGSOC cell lines in a dose-dependent manner with a low nmol/L IC₅₀. Furthermore, treatment with verticillin A induced DNA damage and caused apoptosis in HGSOC cell lines OVCAR4 and OVCAR8. RNA-Seq analysis of verticillin A–treated OVCAR8 cells revealed an enrichment of transcripts in the apoptosis signaling and the oxidative stress response pathways. Mass spectrometry histone profiling confirmed reports that verticillin A caused epigenetic modifications with global changes in histone methylation and acetylation marks. To facilitate <i>in vivo</i> delivery of verticillin A and to monitor its ability to reduce HGSOC tumor burden, verticillin A was encapsulated into an expansile nanoparticle (verticillin A-eNP) delivery system. In an <i>in vivo</i> human ovarian cancer xenograft model, verticillin A-eNPs decreased tumor growth and exhibited reduced liver toxicity compared with verticillin A administered alone. This study confirmed that verticillin A has therapeutic potential for treatment of HGSOC and that encapsulation into expansile nanoparticles reduced liver toxicity.</p></div>