Abstract 2836: H2S donors as radiosensitizers for glioblastoma multiforme (GBM)

Glioblastoma multiforme (GBM) is an extremely aggressive CNS cancer in adults. Radiation is a cornerstone therapy but poses high risk of healthy tissue necrosis. Despite maximal treatment, GBM results in death within 15-21 months of diagnosis. These poor statistics suggest the need for a novel therapy. The use of radiosensitizing agents is a novel approach to minimizing radiation mediated healthy tissue necrosis by allowing use of lower doses to achieve comparable cytotoxic effects. Our lab has shown that sodium sulfide (Na2S), a hydrogen sulfide (H2S) donor, selectively kills GBM (T98G) cells while sparing normal human brain endothelial (hCMEC/D3) cells. Na2S also selectively radiosensitizes GBM cells and enhances cell killing with photon or proton radiation. We are currently exploring Diallyl Trisulfide (DATS), another H2S donor, as a radiosensitizing agent and have demonstrated that DATS can kill GBM cells. At a given dose of 2 Gy, radiation alone decreases T98G survival by 10%. With DATS, survival decreases by 70%, suggesting an additive effect. To determine if DATS increases DNA damage mediated cell death, T98G cells were treated with DATS, radiation, or combined DATS + radiation treatment and then analyzed for γH2AX foci, an indicator of double stand breaks (DSB). Our results show that compared to no treatment, DATS increased the number of γH2AX foci per cell by 1.5-fold, by 3-fold with radiation, and by 4-fold with combined DATS + radiation, an additive response. To elucidate the mechanism of increased DNA damage, a novel fluorescence multiplex host cell reactivation (FM-HCR) reporter system was used to assess repair activity of DSBs in live cells. T98G cells pre-treated with DATS were transfected with reporter plasmids containing site-specific lesions, mimicking radiation-like DNA damage. Repair resulted in expression of a fluorescent reporter protein, which was quantitated using flow cytometry. Our results show that DATS did not alter non-homologous end joining (NHEJ) or homologous repair (HR) activity of DSB. However, DATS did alter base excision repair (BER) activity by decreasing repair of abasic lesions and increasing repair 8oxoG lesions. We hypothesize that this attempted BER via simultaneous strand cleavage by AP endonuclease (Ape1) or glycosylase (Ogg1) may lead to build up of repair intermediates, threatening genomic stability and inducing DSB. Pursuing specific DNA repair biochemical assays is required to further understand this effect of DATS on DNA damage and repair inhibition.

Citation Format: Morni Modi, Camila Weber, Qinqin Xu, Kuanling Chen, Ana Cheong, Zachery Nagel, Lynn Harrison. H2S donors as radiosensitizers for glioblastoma multiforme (GBM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2836.

A Human MSH6 Germline Variant Associated With Systemic Lupus Erythematosus Induces Lupus-like Disease in Mice

OBJECTIVE

To determine if single-nucleotide polymorphisms (SNPs) in DNA repair genes are enriched in individuals with systemic lupus erythematosus (SLE) and if they are sufficient to confer a disease phenotype in a mouse model.

METHODS

Human exome chip data of 2499 patients with SLE and 1230 healthy controls were analyzed to determine if variants in 10 different mismatch repair genes (MSH4, EXO1, MSH2, MSH6, MLH1, MSH3, POLH, PMS2, ML3, and APEX2) were enriched in individuals with SLE. A mouse model of the MSH6 SNP, which was found to be enriched in individuals with SLE, was created using CRISPR/Cas9 gene targeting. Wildtype mice and mice heterozygous and homozygous for the MSH6 variant were then monitored for 2 years for the development of autoimmune phenotypes, including the presence of high levels of antinuclear antibodies (ANA). Additionally, somatic hypermutation frequencies and spectra of the intronic region downstream of the VH J558-rearranged JH4 immunoglobulin gene was characterized from Peyer's patches.

RESULTS

Based on the human exome chip data, the MSH6 variant (rs63750897, p.Ser503Cys) is enriched among patients with SLE versus controls after we corrected for ancestry (odds ratio = 8.39, P = 0.0398). Mice homozygous for the MSH6 variant (Msh6S502C/S502C ) harbor significantly increased levels of ANA. Additionally, the Msh6S502C/S502C mice display a significant increase in the infiltration of CD68+ cells (a marker for monocytes and macrophages) into the lung alveolar space as well as apoptotic cells. Furthermore, characterization of somatic hypermutation in these mice reveals an increase in the DNA polymerase η mutational signature.

CONCLUSION

An MSH6 mutation that is enriched in humans diagnosed with lupus was identified. Mice harboring this Msh6 mutation develop increased autoantibodies and an inflammatory lung disease. These results suggest that the human MSH6 variant is linked to the development of SLE.

Human Variation in DNA Repair, Immune Function, and Cancer Risk

DNA damage constantly threatens genome integrity, and DNA repair deficiency is associated with increased cancer risk. An intuitive and widely accepted explanation for this relationship is that unrepaired DNA damage leads to carcinogenesis due to the accumulation of mutations in somatic cells. But DNA repair also plays key roles in the function of immune cells, and immunodeficiency is an important risk factor for many cancers. Thus, it is possible that emerging links between inter-individual variation in DNA repair capacity and cancer risk are driven, at least in part, by variation in immune function, but this idea is underexplored. In this review we present an overview of the current understanding of the links between cancer risk and both inter-individual variation in DNA repair capacity and inter-individual variation in immune function. We discuss factors that play a role in both types of variability, including age, lifestyle, and environmental exposures. In conclusion, we propose a research paradigm that incorporates functional studies of both genome integrity and the immune system to predict cancer risk and lay the groundwork for personalized prevention.

Gene expression and DNA methylation changes in the hypothalamus and hippocampus of adult rats developmentally exposed to bisphenol A or ethinyl estradiol: a CLARITY-BPA consortium study

Bisphenol A (BPA), an endocrine disrupting chemical (EDC), is a ubiquitous pollutant. As part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA), we sought to determine whether exposure of Sprague-Dawley rats to 2,500 μg/kg/day BPA (BPA) or 0.5 μg/kg/day ethinyl estradiol (EE) from gestational day 6 through postnatal day 21 induces behavior-relevant gene expression and DNA methylation changes in hippocampus and hypothalamus at adulthood. RNA and DNA were isolated from both regions. Expression of ten genes (Dnmt1, Dnmt3a, Dnmt3b, Esr1, Esr2, Avp, Ar, Oxt, Otr, and Bdnf) presumably altered by early-life BPA/EE exposure was examined. Three genes (Bdnf, Dnmt3b, and Esr1) were studied for DNA methylation changes in their putative 5' promoter regions. Molecular changes in hippocampus were correlated to prior Barnes maze performance, including sniffing correct holes, distance traveled, and velocity. Exposure to BPA and/or EE disrupted patterns of sexually dimorphic gene expression/promoter DNA methylation observed in hippocampus and hypothalamus of controls. In the hippocampus of female offspring, BPA exposure resulted in hypermethylation of the putative 5' promoter region of Bdnf, while EE exposure induced hypomethylation. Bdnf methylation was weakly associated with Bdnf expression in hippocampi of female rats. Hippocampal Bdnf expression in females showed a weak negative association with sniffing correct hole in Barnes maze. Hippocampal expression of Avp, Esr2, Oxt, and Otr was strongly associated with velocity of control rats in Barnes maze. Findings suggest BPA exposure induced non-EE-like gene expression and epigenetic changes in adult rat hippocampi, a region involved in spatial navigation.

Prostate Cancer Risk and DNA Methylation Signatures in Aging Rats following Developmental BPA Exposure: A Dose-Response Analysis

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 5,000 μg 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 10–100 μg/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.

Gestational high-fat diet and bisphenol A exposure heightens mammary cancer risk

In utero exposure to bisphenol A (BPA) increases mammary cancer susceptibility in offspring. High-fat diet is widely believed to be a risk factor of breast cancer. The objective of this study was to determine whether maternal exposure to BPA in addition to high-butterfat (HBF) intake during pregnancy further influences carcinogen-induced mammary cancer risk in offspring, and its dose-response curve. In this study, we found that gestational HBF intake in addition to a low-dose BPA (25 µg/kg BW/day) exposure increased mammary tumor incidence in a 50-day-of-age chemical carcinogen administration model and altered mammary gland morphology in offspring in a non-monotonic manner, while shortening tumor-free survival time compared with the HBF-alone group. In utero HBF and BPA exposure elicited differential effects at the gene level in PND21 mammary glands through DNA methylation, compared with HBF intake in the absence of BPA. Top HBF + BPA-dysregulated genes (ALDH1B1, ASTL, CA7, CPLX4, KCNV2, MAGEE2 and TUBA3E) are associated with poor overall survival in The Cancer Genomic Atlas (TCGA) human breast cancer cohort (n = 1082). Furthermore, the prognostic power of the identified genes was further enhanced in the survival analysis of Caucasian patients with estrogen receptor-positive tumors. In conclusion, concurrent HBF dietary and a low-dose BPA exposure during pregnancy increases mammary tumor incidence in offspring, accompanied by alterations in mammary gland development and gene expression, and possibly through epigenetic reprogramming.

Abstract 2537: MicroRNA targeting anti-apoptotic and G2/M pathways as therapeutic targets for castration resistant prostate cancer

Prostate cancer (PC) is one of the most common cancers in men. Unfortunately, limited treatment options currently exist for those who have developed advanced castration-resistant PC (CRPC). G-1 is a GPER1/GPR30 agonist, and a promising candidate for CRPC therapy. G-1 is effective in halting the growth of CR tumors but not those grown in intact hosts. These findings suggest GPER1 is a therapeutic target for CRPC. We found that G-1, through activation of GPER1, inhibited growth of CRPC cells via cell-cycle arrest at the G2-M phase, probably leading to mitotic catastrophy. However, the exact mode of action of G-1 was not known. To better understand the pathways involved in G-1 action, we conducted a genome-wide mRNA-seq and miRNA-seq study on G-1 treated xenografts. We identified a panel of novel G-1-associated tumor suppressive miRNAs and genes. Moreover, Ingenuity Pathway Analysis revealed that the G-1 differentially regulated genes are involved in “Cellular Growth and Proliferation”, “endocrine function” and “Cancer” pathways. We validated the expression of the key miRNA (miR-34c, miR-10b, miR-138 and miR218) and genes in G-1 treated castration resistant xenografts and cell lines (C4-2 and 22Rv1). Furthermore, we have shown the tumor suppressor function of these miRNA in cell survival, migration, and invasion. The predicted target genes were next examined for decreased expression by qRT-PCR. We confirmed decreased expression of some of the downstream targets, which consist of genes involved in cell cycle regulation (CCNA and CCND, CDK1, CDK4, PLK1), cell survival (Bcl2, Survivin), cell migration/F-actin formation (LASP, PCDH7, ITGA9, ROBO1, SLIT1) and G2/M checkpoint (CDK1, PLK1, BCL-2 Survivin). Thus these miRNAs - miR-34c, miR-10b, miR-138 and miR218 - are ideal candidates for therapy of CRPC.

Citation Format: Pheruza Tarapore, Sarah To, Bin Ouyang, Yuet-Kin Leung, Ana Cheong, Shuk-mei Ho. MicroRNA targeting anti-apoptotic and G2/M pathways as therapeutic targets for castration resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2537. doi:10.1158/1538-7445.AM2017-2537

Abstract 4826: Maternal high butter fat intake heightens mammary cancer risk in offsprings gestationally exposed to bisphenol A at environmentally relevant dose

In utero exposure to bisphenol A (BPA) at 250ug/kg BW was shown to augment mammary cancer risk in rodent models. High fat diet is widely believed to be a major risk of breast cancer (BCa). It is therefore important to investigate whether maternal high fat intake could potentially heighten mammary cancer risk associated to gestational BPA exposure. In this study, we exposed Sprague Dawley rats with different doses of BPA (2.5-2500ug/kg BW) mixed with high butter-based diet (HBF) in the period from preconception to birth. DMBA-PND50 protocol was followed. In the presence of HBF, we observed non-monotonic effects of BPA in cancer incidence as well as in the number of terminal end buds of PND21 mammary glands. Both results were peaked at a dosage of 25ug/kg BW BPA and the effects were significant when compared with HBF alone group. We further analyzed transcriptomic data of microdissected epithelia of PND21 mammary glands from BPA (25ug/kg BW) group as well as HBF group and revealed that two specific cancer networks involving ERK and androgen receptor signaling were dysregulated. DNA methylation is one of the key mechanisms to dysregulate and impair the transcription of two selected top genes, Car7 and Kcnv2, as supported by our bisulfite-sequencing data. These data suggest that in utero BPA exposure could epigenetically modify gene expression and predispose cancer risk during early development. More importantly, some BPA genes are of high human relevance because seven selected BPA genes could dichotomize patients into two groups with significant difference in overall survival in a TCGA cancer cohort. The prognostic power of the genes was further enhanced in the survival analysis of Caucasian with ER positive patients. In conclusion, our data strongly suggest that BPA predisposes higher cancer risk by dysregulating gene expression during early mammary gland development in the presence of HBF, which could facilitate cancer development later in life.

Citation Format: Yuet-Kin Leung, Vinothini Govindarajah, Ana Cheong, Dan Song, Xuegong Zhu, Jun Ying, Ady Kendler, Mario Medvedovic, Scott Belcher, Shuk-Mei Ho. Maternal high butter fat intake heightens mammary cancer risk in offsprings gestationally exposed to bisphenol A at environmentally relevant dose [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4826. doi:10.1158/1538-7445.AM2017-4826

DNA methylome changes by estradiol benzoate and bisphenol A links early-life environmental exposures to prostate cancer risk

Developmental exposure to endocrine-disrupting chemicals (EDCs), 17β-estradiol-3-benzoate (EB) and bisphenol A (BPA), increases susceptibility to prostate cancer (PCa) in rodent models. Here, we used the methylated-CpG island recovery assay (MIRA)-assisted genomic tiling and CpG island arrays to identify treatment-associated methylome changes in the postnatal day (PND)90 dorsal prostate tissues of Sprague-Dawley rats neonatally (PND1, 3, and 5) treated with 25 µg/pup or 2,500 µg EB/kg body weight (BW) or 0.1 µg BPA/pup or 10 µg BPA/kg BW. We identified 111 EB-associated and 86 BPA-associated genes, with 20 in common, that have significant differentially methylated regions. Pathway analysis revealed cancer as the top common disease pathway. Bisulfite sequencing validated the differential methylation patterns observed by array analysis in 15 identified candidate genes. The methylation status of 7 (Pitx3, Wnt10b, Paqr4, Sox2, Chst14, Tpd52, Creb3l4) of these 15 genes exhibited an inverse correlation with gene expression in tissue samples. Cell-based assays, using 5-aza-cytidine-treated normal (NbE-1) and cancerous (AIT) rat prostate cells, added evidence of DNA methylation-mediated gene expression of 6 genes (exception: Paqr4). Functional connectivity of these genes was linked to embryonic stem cell pluripotency. Furthermore, clustering analyses using the dataset from The Cancer Genome Atlas revealed that expression of this set of 7 genes was associated with recurrence-free survival of PCa patients. In conclusion, our study reveals that gene-specific promoter methylation changes, resulting from early-life EDC exposure in the rat, may serve as predictive epigenetic biomarkers of PCa recurrence, and raises the possibility that such exposure may impact human disease.

Environmental factors, epigenetics, and developmental origin of reproductive disorders

Sex-specific differentiation, development, and function of the reproductive system are largely dependent on steroid hormones. For this reason, developmental exposure to estrogenic and anti-androgenic endocrine disrupting chemicals (EDCs) is associated with reproductive dysfunction in adulthood. Human data in support of "Developmental Origins of Health and Disease" (DOHaD) comes from multigenerational studies on offspring of diethylstilbestrol-exposed mothers/grandmothers. Animal data indicate that ovarian reserve, female cycling, adult uterine abnormalities, sperm quality, prostate disease, and mating behavior are susceptible to DOHaD effects induced by EDCs such as bisphenol A, genistein, diethylstilbestrol, p,p'-dichlorodiphenyl-dichloroethylene, phthalates, and polyaromatic hydrocarbons. Mechanisms underlying these EDC effects include direct mimicry of sex steroids or morphogens and interference with epigenomic sculpting during cell and tissue differentiation. Exposure to EDCs is associated with abnormal DNA methylation and other epigenetic modifications, as well as altered expression of genes important for development and function of reproductive tissues. Here we review the literature exploring the connections between developmental exposure to EDCs and adult reproductive dysfunction, and the mechanisms underlying these effects.

Exposure of Human Prostaspheres to Bisphenol A Epigenetically Regulates SNORD Family Noncoding RNAs via Histone Modification

Bisphenol A (BPA) is a ubiquitous endocrine disruptor exerting lifelong effects on gene expression in rodent prostate cancer (PCa) models. Here, we aimed to determine whether epigenetic events mediating the action of BPA on human prostaspheres enriched in epithelial stem-like/progenitor cells is linked to PCa. We performed genome-wide transcriptome and methylome analyses to identify changes in prostaspheres treated with BPA (10 nM, 200 nM, and 1000 nM) or estradiol-17β (E2) (0.1 nM) for 7 days and validated changes in expression, methylation, and histone marks in parallel-treated prostaspheres. BPA/E2-treatment altered expression of 91 genes but not the methylation status of 485,000 CpG sites in BPA/E2-treated prostaspheres. A panel of 26 genes was found repressed in all treatment groups. Fifteen of them were small nucleolar RNAs with C/D motif (SNORDs), which are noncoding, small nucleolar RNAs known to regulate ribosomal RNA assembly and function. Ten of the most down-regulated SNORDs were further studied. All 10 were confirmed repressed by BPA, but only 3 ratified as E2-repressed. SNORD suppression showed no correlation with methylation status changes in CpG sites in gene regulatory regions. Instead, BPA-induced gene silencing was found to associate with altered recruitments of H3K9me3, H3K4me3, and H3K27me3 to 5'-regulatory/exonic sequences of 5 SNORDs. Expression of 4 out of these 5 SNORDs (SNORD59A, SNORD82, SNORD116, and SNORD117) was shown to be reduced in PCa compared with adjacent normal tissue. This study reveals a novel and unique action of BPA in disrupting expression of PCa-associated SNORDs and a putative mechanism for reprogramming the prostasphere epigenome via histone modification.

Effects of High-Butterfat Diet on Embryo Implantation in Female Rats Exposed to Bisphenol A

Bisphenol A (BPA) is an endocrine disruptor associated with poor pregnancy outcomes in human and rodents. The effects of butterfat diets on embryo implantation and whether it modifies BPA's actions are currently unknown. We aimed to determine the effects of butterfat diet on embryo implantation success in female rats exposed to an environmentally relevant dose of BPA. Female Sprague-Dawley rats were exposed to dietary butterfat (10% or 39% kcal/kg body weight [BW]) in the presence or absence of BPA (250 μg/kg BW) or ethinylestradiol (0.1 μg/kg BW) shortly before and during pregnancy to assess embryo implantation potentials by preimplantation development and transport, in vitro blastulation, outgrowth, and implantation. On gestational day (GD) 4.5, rats treated with BPA alone had higher serum total BPA level (2.3-3.7 ng/ml). They had more late-stage preimplantation embryos, whereas those receiving high butterfat (HBF) diet had the most advanced-stage embryos; dams cotreated with HBF and BPA had the most number of advanced embryos. BPA markedly delayed embryo transport to the uterus, but neither amount of butterfat had modifying effects. An in vitro implantation assay showed HBF doubled the outgrowth area, with BPA having no effect. In vivo, BPA reduced the number of implanted embryos on GD8, and cotreatment with HBF eliminated this adverse effect. HBF diet overall resulted in more and larger GD8 embryos. This study reveals the implantation disruptive effects of maternal exposure to an environmentally relevant dose of BPA and identifies HBF diet as a modifier of BPA in promoting early embryonic health.

Mesenchymal stem/stromal cells in post-menopausal endometrium

STUDY QUESTION

Does post-menopausal endometrium contain mesenchymal stem/stromal cells (MSC) that have adult stem cell properties and can be prospectively isolated from a biopsy?

SUMMARY ANSWER

Perivascular W5C5(+) cells isolated from post-menopausal endometrial biopsies displayed characteristic MSC properties of clonogenicity, multipotency and surface phenotype irrespective of whether the women were or were not pre-treated with estrogen to regenerate the endometrium.

WHAT IS KNOWN ALREADY

Recently MSCs have been identified in human premenopausal endometrium, and can be prospectively isolated using a single marker, W5C5/SUSD2.

STUDY DESIGN, SIZE, DURATION

Endometrial tissue of both the functional and basal layers, from 17 premenopausal (pre-MP) women, 19 post-menopausal (post-MP) women without hormonal treatment and 15 post-menopausal women on estrogen replacement therapy (post-MP+ E2), was collected through a prospective phase IV clinical trial over 2 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Post-menopausal women <65 years of age were treated with or without E2 for 6-8 weeks prior to tissue collection. Serum E2 levels were determined by estradiol immunoenzymatic assay. Endometrial tissue was obtained from women by biopsy (curettage) just prior to the hysterectomy. The effect of E2 on endometrial thickness and glandular and luminal epithelial height was determined using image analysis. Endometrial tissue was dissociated into single cell suspensions and MSC properties were examined in freshly isolated and short-term cultured, magnetic bead-purified W5C5(+) cells. MSC properties were assessed using clonogenicity, serial cloning, mesodermal differentiation in adipogenic, chondrogenic, osteogenic and myogenic induction culture media, and surface phenotype analysis by flow cytometry. Estrogen receptor α expression in W5C5(+) cells was examined using dual colour immunofluorescence. Vascularity was analysed using CD34 and alpha smooth muscle actin immunostaining and subsequent image analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

A small population of stromal cells with MSC properties was purified with the W5C5 antibody from post-menopausal endometrium, whether atrophic from low circulating estrogen or regenerated from systemic estrogen treatment, similar to premenopausal endometrium. The MSC derived from post-menopausal endometrium treated with or without E2 fulfilled the minimum MSC criteria: clonogenicity, surface phenotype (CD29(+), CD44(+), CD73(+), CD105(+), CD140b(+), CD146(+)) and multipotency. The post-menopausal endometrial MSCs also showed comparable properties to premenopausal eMSC with respect to self-renewal in vitro and W5C5 expression. The W5C5(+) cells were located perivascularly as expected and did not express estrogen receptor α.

LIMITATIONS, REASONS FOR CAUTION

The properties of the MSC derived from post-menopausal endometrium were evaluated in vitro and their in vivo tissue reconstitution capacity has not been established as it has for premenopausal endometrial MSC.

WIDER IMPLICATIONS OF THE FINDINGS

The endometrium is an accessible source of MSC obtainable with minimum morbidity that could be used for future clinical applications as a cell-based therapy. This study shows that menopausal women can access their endometrial MSC by a simple biopsy for use in autologous therapies, particularly if their endometrium has been regenerated by short-term E2 treatment, provided they have an intact uterus and are not contraindicated for short-term E2 treatment. Endometrial MSC in post-menopausal women possess key MSC properties and are a promising source of MSC independent of a woman's age.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the National Health and Medical Research Council (NHMRC) of Australia grant (1021126) (C.E.G., A.R.) and Senior Research Fellowship (1042298) (C.E.G.), Australian Gynaecological Endoscopic Society grant (A.R.) , Monash International Postgraduate Research Scholarship (DU), Australian Stem Cell Centre, South East Melbourne Alliance for Regenerative Therapies and Australian Stem Cell Centre top up scholarships (DU) and Victorian Government's Operational Infrastructure Support Program. Competing interests: AR receives Preceptorship fees from AMS, advisory board fees and sponsored study from Astellas, and conducts investigator led studies sponsored by AMS and Boston Scientific for other projects.

TRIAL REGISTRATION NUMBER

CTNRN12610000563066.

Screening for cardiovascular disease risk factors at baseline and post intervention among adults with intellectual disabilities in an urbanised Asian society

BACKGROUND

Adults with intellectual disabilities (ID) face significant barriers to screening participation. We determined predictors for regular cardiovascular health screening at baseline among adults with ID in Singapore, and evaluated the effectiveness of a 3-month screening intervention.

METHODS

The study population involved all adults with ID aged ≥40 years receiving services from the Movement for the Intellectually Disabled of Singapore (MINDS), the largest such provider in Singapore. Over 3 months in 2011, adult clients not screened regularly at baseline for hypertension, diabetes and dyslipidaemia were offered free and convenient blood pressure, fasting blood glucose and lipid testing; data on other cardiovascular disease risk factors were also collected. Chi-square and logistic regression identified predictors of regular screening at baseline.

RESULTS

Participation was 95.0% (227/239). At baseline, among adults with ID, 61.8% (118/191), 24.8% (52/210) and 18.2% (34/187) had gone for regular hypertension, diabetes and dyslipidaemia screening respectively; post intervention, rates rose to 96.9%, 89.5% and 88.8% respectively. Prevalence of cardiovascular disease risk factors (22.5% with hypertension, 10.6% with diabetes, 34.8% with dyslipidaemia, 10.7% obese and 90.6% lacking regular exercise) was high compared against the general population. While receiving residential services was associated with regular hypertension screening, receiving non-residential services and being independently mobile were associated with regular participation in fasting blood tests (all P < 0.05).

CONCLUSION

Cardiovascular disease risk factors are common among adults with ID and clinicians should proactively screen such populations. Provision of free and convenient screening for cardiovascular disease risk improved screening participation.

Pacritinib (SB1518), a JAK2/FLT3 inhibitor for the treatment of acute myeloid leukemia

FMS-like tyrosine kinase 3 (FLT3) is the most commonly mutated gene found in acute myeloid leukemia (AML) patients and its activating mutations have been proven to be a negative prognostic marker for clinical outcome. Pacritinib (SB1518) is a tyrosine kinase inhibitor (TKI) with equipotent activity against FLT3 (IC₅₀=22 n) and Janus kinase 2 (JAK2, IC₅₀=23 n). Pacritinib inhibits FLT3 phosphorylation and downstream STAT, MAPK and PI3 K signaling in FLT3-internal-tandem duplication (ITD), FLT3-wt cells and primary AML blast cells. Oral administration of pacritinib in murine models of FLT3-ITD-driven AML led to significant inhibition of primary tumor growth and lung metastasis. Upregulation of JAK2 in FLT3-TKI-resistant AML cells was identified as a potential mechanism of resistance to selective FLT3 inhibition. This resistance could be overcome by the combined FLT3 and JAK2 activities of pacritinib in this cellular model. Our findings provide a rationale for the clinical evaluation of pacritinib in AML including patients resistant to FLT3-TKI therapy.

Local delivery of the KCa3.1 blocker, TRAM-34, prevents acute angioplasty-induced coronary smooth muscle phenotypic modulation and limits stenosis

OBJECTIVE

We previously demonstrated that upregulation of intermediate-conductance Ca(2+)-activated K(+) channels (K(Ca)3.1) is necessary for mitogen-induced phenotypic modulation in isolated porcine coronary smooth muscle cells (SMCs). The objective of the present study was to determine the role of K(Ca)3.1 in the regulation of coronary SMC phenotypic modulation in vivo using a swine model of postangioplasty restenosis.

METHODS AND RESULTS

Balloon angioplasty was performed on coronary arteries of swine using either noncoated or balloons coated with the specific K(Ca)3.1 blocker TRAM-34. Expression of K(Ca)3.1, c-jun, c-fos, repressor element-1 silencing transcription factor (REST), smooth muscle myosin heavy chain (SMMHC), and myocardin was measured using qRT-PCR in isolated medial cells 2 hours and 2 days postangioplasty. K(Ca)3.1, c-jun, and c-fos mRNA levels were increased 2 hours postangioplasty, whereas REST expression decreased. SMMHC expression was unchanged at 2 hours, but decreased 2 days postangioplasty. Use of TRAM-34 coated balloons prevented K(Ca)3.1 upregulation and REST downregulation at 2 hours, SMMHC and myocardin downregulation at 2 days, and attenuated subsequent restenosis 14 and 28 days postangioplasty. Immunohistochemical analysis demonstrated corresponding changes at the protein level.

CONCLUSIONS

Blockade of K(Ca)3.1 by delivery of TRAM-34 via balloon catheter prevented smooth muscle phenotypic modulation and limited subsequent restenosis.

Upregulated TRPC1 channel in vascular injury in vivo and its role in human neointimal hyperplasia

Occlusive vascular disease is a widespread abnormality leading to lethal or debilitating outcomes such as myocardial infarction and stroke. It is part of atherosclerosis and is evoked by clinical procedures including angioplasty and grafting of saphenous vein in bypass surgery. A causative factor is the switch in smooth muscle cells to an invasive and proliferative mode, leading to neointimal hyperplasia. Here we reveal the importance to this process of TRPC1, a homolog of Drosophila transient receptor potential. Using 2 different in vivo models of vascular injury in rodents we show hyperplasic smooth muscle cells have upregulated TRPC1 associated with enhanced calcium entry and cell cycle activity. Neointimal smooth muscle cells after balloon angioplasty of pig coronary artery also express TRPC1. Furthermore, human vein samples obtained during coronary artery bypass graft surgery commonly exhibit an intimal structure containing smooth muscle cells that expressed more TRPC1 than the medial layer cells. Veins were organ cultured to allow growth of neointimal smooth muscle cells over a 2-week period. To explore the functional relevance of TRPC1, we used a specific E3-targeted antibody to TRPC1 and chemical blocker 2-aminoethoxydiphenyl borate. Both agents significantly reduced neointimal growth in human vein, as well as calcium entry and proliferation of smooth muscle cells in culture. The data suggest upregulated TRPC1 is a general feature of smooth muscle cells in occlusive vascular disease and that TRPC1 inhibitors have potential as protective agents against human vascular failure.

Functional up-regulation of KCNA gene family expression in murine mesenteric resistance artery smooth muscle

This study focused on the hypothesis that KCNA genes (which encode K(V)alpha1 voltage-gated K(+) channels) have enhanced functional expression in smooth muscle cells of a primary determinant of peripheral resistance - the small mesenteric artery. Real-time PCR methodology was developed to measure cell type-specific in situ gene expression. Profiles were determined for arterial myocyte expression of RNA species encoding K(V)alpha1 subunits as well as K(V)beta1, K(V)alpha2.1, K(V)gamma9.3, BK(Ca)alpha1 and BK(Ca)beta1. The seven major KCNA genes were expressed and more readily detected in endothelium-denuded mesenteric resistance artery compared with thoracic aorta; quantification revealed dramatic differential expression of one to two orders of magnitude. There was also four times more RNA encoding K(V)alpha2.1 but less or similar amounts encoding K(V)beta1, K(V)gamma9.3, BK(Ca)alpha1 and BK(Cabeta)1. Patch-clamp recordings from freshly isolated smooth muscle cells revealed dominant K(V)alpha1 K(+) current and current density twice as large in mesenteric cells. Therefore, we suggest the increased RNA production of the resistance artery impacts on physiological function, although there is quantitatively less K(+) current than might be expected. The mechanism conferring up-regulated expression of KCNA genes may be common to all the gene family and play a functional role in the physiological control of blood pressure.

Discrete store-operated calcium influx into an intracellular compartment in rabbit arteriolar smooth muscle

This study tested the hypothesis that store-operated channels (SOCs) exist as a discrete population of Ca2+ channels activated by depletion of intracellular Ca(2+) stores in cerebral arteriolar smooth muscle cells and explored their direct contractile function. Using the Ca2+ indicator fura-PE3 it was observed that depletion of sarcoplasmic reticulum (SR) Ca2+ by inhibition of SR Ca2+-ATPase (SERCA) led to sustained elevation of [Ca2+]i that depended on extracellular Ca2+ and slightly enhanced Mn2+ entry. Enhanced background Ca2+ influx did not explain the raised [Ca2+]i in response to SERCA inhibitors because it had marked gadolinium (Gd3+) sensitivity, which background pathways did not. Effects were not secondary to changes in membrane potential. Thus SR Ca2+ depletion activated SOCs. Strikingly, SOC-mediated Ca2+ influx did not evoke constriction of the arterioles, which were in a resting state. This was despite the fura-PE3-indicated [Ca2+]i rise being greater than that evoked by 20 mM [K+]o (which did cause constriction). Release of endothelial vasodilators did not explain the absence of SOC-mediated constriction, nor did a change in Ca2+ sensitivity of the contractile proteins. We suggest SOCs are a discrete subset of Ca2+ channels allowing Ca2+ influx into a 'non-contractile' compartment in cerebral arteriolar smooth muscle cells.

Activation thresholds of K(V), BK andCl(Ca) channels in smooth muscle cells in pial precapillary arterioles

We have previously shown expression of voltage-gated K+ channels (K(V)) in smooth muscle of cerebral arterioles and suggested the channels function to oppose voltage-dependent Ca2+ entry. However, other studies indicate that large conductance Ca2+-activated K+ (BK) channels serve this function and chloride (Cl-) channels may have the opposite effect. In this study we compared the activation thresholds and absolute current amplitudes for K(V) channels, BK channels and Cl- channels at physiological membrane potentials in intact precapillary arterioles from the rabbit cerebral circulation. Patch-clamp recordings were made to measure current and membrane potential, and a video scan line was used to detect external diameter. Two strategies to determine the basal current-voltage relationship of BK channels showed the channels contributed current only at voltages positive of -35 mV, even though voltage-dependent Ca2+-entry occurred. Ca2+-activated and niflumic acid-sensitive Cl- current was detected but, between -50 and -10 mV, both BK and Cl- channel currents were much smaller and contributed less to the membrane potential compared with K(V) channel current. Furthermore, in the absence of an exogenous vasoconstrictor agent, block of K(V) channels but not BK or Cl- channels caused constriction, although in the presence of endothelin-1 block of BK or K(V) channels caused constriction. The data indicate K(V) channels are the first inhibitory mechanism to activate when there is depolarisation in precapillary arteriolar smooth muscle cells of the cerebral circulation.

Na+-H+ exchanger 3 (NHE3) is present in lipid rafts in the rabbit ileal brush border: a role for rafts in trafficking and rapid stimulation of NHE3

1. Rabbit ileal Na+-absorbing cell Na+-H+ exchanger 3 (NHE3) was shown to exist in three pools in the brush border (BB), including a population in lipid rafts. Approximately 50% of BB NHE3 was associated with Triton X-100-soluble fractions and the other approximately 50% with Triton X-100-insoluble fractions; approximately 33% of the detergent-insoluble NHE3 was present in cholesterol-enriched lipid microdomains (rafts). 2. The raft pool of NHE3 was involved in the stimulation of BB NHE3 activity with epidermal growth factor (EGF). Both EGF and clonidine treatments were associated with a rapid increase in the total amount of BB NHE3. This EGF- and clonidine-induced increase of BB NHE3 was associated with an increase in the raft pool of NHE3 and to a smaller extent with an increase in the total detergent-insoluble fraction, but there was no change in the detergent-soluble pool. In agreement with the rapid increase in the amount of NHE3 in the BB, EGF also caused a rapid stimulation of BB Na+-H+ exchange activity. 3. Disrupting rafts by removal of cholesterol with methyl-beta-cyclodextrin (MbetaCD) or destabilizing the actin cytoskeleton with cytochalasin D decreased the amount of NHE3 in early endosomes isolated by OptiPrep gradient fractionation. Specifically, NHE3 was shown to associate with endosomal vesicles immunoisolated by anti-EEA1 (early endosomal autoantigen 1) antibody-coated magnetic beads and the endosome-associated NHE3 was decreased by cytochalasin D and MbetaCD treatment. 4. We conclude that: (i) a pool of ileal BB NHE3 exists in lipid rafts; (ii) EGF and clonidine increase the amount of BB NHE3; (iii) lipid rafts and to a lesser extent, the cytoskeleton, but not the detergent-soluble NHE3 pool, are involved in the EGF- and clonidine-induced acute increase in amount of BB NHE3; (iv) lipid rafts and the actin cytoskeleton play important roles in the basal endocytosis of BB NHE3.

K(V)alpha1 channels in murine arterioles: differential cellular expression and regulation of diameter

The primary objectives of this study were to reveal cell-specific expression patterns and functions of voltage-gated K(+) channel (K(V)alpha1) subunits in precapillary arterioles of the murine cerebral circulation. K(V)alpha1 were detected using peptide-specific antibodies in immunofluorescence and Western blotting assays. K(V)1.2 was localized almost exclusively to endothelial cells, whereas K(V)1.5 was discretely localized to the nerves and nerve terminals that innervate the arterioles. K(V)1.5 also localized specifically to arteriolar nerves in human pial membrane. K(V)1.5 was notable for its absence from smooth muscle cells. K(V)1.3, K(V)1.4, and K(V)1.6 were localized to endothelial and smooth muscle cells, although K(V)1.4 had a low expression level. K(V)1.1 was not expressed. Therefore, we show that different cell types of pial arterioles have distinct physiological expression profiles of K(V)alpha1, conferring the possibility of differential modulation by extracellular and second messengers. Furthermore, we show recombinant agitoxin-2 and margatoxin are potent vasoconstrictors, suggesting that K(V)alpha1 subunits have a major function in determining arteriolar resistance to blood flow.

Expression and function of native potassium channel [K(V)alpha1] subunits in terminal arterioles of rabbit

1. In this study we investigated the expression and function of the K(V)alpha1 subfamily of voltage-gated K(+) channels in terminal arterioles from rabbit cerebral circulation. 2. K(+) current was measured from smooth muscle cells within intact freshly isolated arteriolar fragments. Current activated on depolarisation positive of about -45 mV and a large fraction of this current was blocked by 3,4-diaminopyridine (3,4-DAP) or 4-aminopyridine (4-AP), inhibitors of K(V) channels. Expression of cRNA encoding K(V)1.6 in Xenopus oocytes also generated a 4-AP-sensitive K(+) current with a threshold for activation near -45 mV. 3. Immunofluorescence labelling revealed K(V)1.2 to be specifically localised to endothelial cells, and K(V)1.5 and K(V)1.6 to plasma membranes of smooth muscle cells. 4. K(V) channel current in arteriolar fragments was blocked by correolide (which is specific for the K(V)alpha1 family of K(V) channels) but was resistant to recombinant agitoxin-2 (rAgTX2; which inhibits K(V)1.6 but not K(V)1.5). Heterologously expressed K(V)2.1 was resistant to correolide, and K(V)1.6 was blocked by rAgTX2. 5. Arterioles that were mildly preconstricted and depolarised by 0.1-0.3 nM endothelin-1 constricted further in response to 3,4-DAP, 4-AP or correolide, but not to rAgTX2. 6. We suggest that K(V)alpha1 channels are expressed in smooth muscle cells of terminal arterioles, underlie a major part of the voltage-dependent K(+) current, and have a physiological function to oppose vasoconstriction. K(V)alpha1 complexes without K(V)1.5 appear to be uncommon.

Block of human aorta Kir6.1 by the vascular KATP channel inhibitor U37883A

1. A human aorta cDNA library was screened at low stringency with a rat pancreatic Kir6.1 cDNA probe and a homologue of Kir6.1 (hKir6.1) was isolated and sequenced. 2. Metabolic poisoning of Xenopus laevis oocytes with sodium azide and application of the K+ channel opener drug diazoxide induced K+ channel currents in oocytes co-injected with cRNA for hKir6.1 and hamster sulphonylurea receptor (SUR1), but not in oocytes injected with water or cRNA for hKir6.1 or SUR1 alone. 3. K+ channel currents due to hKir6.1+SUR1 or mouse Kir6.2+SUR1 were strongly inhibited by 1 microM glibenclamide. K+-current carried by hKir6.1+SUR1 was inhibited by the putative vascular-selective KATP channel inhibitor U37883A (IC50 32 microM) whereas current carried by Kir6.2+SUR1 or Shaker K+ channels was unaffected. 4. The data support the hypothesis that hKir6.1 is a component of the vascular KATP channel, although the lower sensitivity of hKir6.1+SUR1 to U37883A compared with native vascular tissues suggests the need for another factor or subunit. Furthermore, the data suggest that pharmacology of KATP channels can be determined by the pore-forming subunit as well as the sulphonylurea receptor and point to a molecular basis for the pharmacological distinction between vascular and pancreatic/cardiac KATP channels.