bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A083: Neutrophils promote metastasis of invasive lobular carcinoma
Authors: Coffelt Seth B. , Doornebal Chris W. , Kersten Kelly , Ciampricotti Metamia , Hau Cheei-Sing , Vrijland Kim , Weiden Jorieke , Jonkers Jos , Visser. Karin E. de
Published: May 2015

The multistep process of metastasis is highly dependent on the intrinsic mutations that accumulate in cancer cells. However, recent experimental evidence has shown that these mutations are not sufficient to facilitate metastatic disease. Cues from the tumor microenvironment are also required. In order to understand how systemic changes might affect metastasis formation, we profiled the cellular and molecular alterations in various organs of K14cre;EcdF/F;p53F/F mammary tumor-bearing mice – a model of invasive lobular breast cancer. Among all immune cells, increased neutrophil accumulation was the most pronounced. To test the functional importance of neutrophils in the metastatic process, we utilized our recently described model of spontaneous metastasis. This model is based on the transplantation of K14cre;EcdF/F;p53F/F tumor pieces into wild-type recipient mice, and subsequent surgical removal of the primary tumor, permitting us to investigate neutrophil function in both the neoadjuvant and adjuvant settings. Interestingly, mice treated with neutrophil-depleting antibodies in the neoadjuvant setting displayed a profound reduction in pulmonary metastasis, whereas metastases in the adjuvant group were equivalent to controls. These data indicate that neutrophils play a prominent role during the very early stages of the metastatic cascade. Our preliminary data suggest that these tumor-educated neutrophils can suppress the activation of T cells, as one mechanism by which they may promote metastasis. In addition, cytokine analysis of K14cre;EcdF/F;p53F/F mammary tumors demonstrated an increase in the IL17 pathway when compared to wild-type mammary glands. Subsets of T cells are known producers of IL17 and this pathway regulates neutrophil expansion indirectly. In accordance with this, K14cre;EcdF/F;p53F/F mice lacking the adaptive immune system displayed reduced IL17 levels and reduced circulating neutrophils. Current efforts are underway to determine whether T cells play a role in the pro-metastatic function of neutrophils. Together, these findings indicate that neutrophils are crucial for the establishment of breast cancer metastasis.

Citation Format: Seth B. Coffelt, Chris W. Doornebal, Kelly Kersten, Metamia Ciampricotti, Cheei-Sing Hau, Kim Vrijland, Jorieke Weiden, Jos Jonkers, Karin E. de Visser. Neutrophils promote metastasis of invasive lobular carcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A083.
Abstract A092: Molecular mechanisms of early metastatic dissemination in breast cancer
Authors: Hosseini Hedayatollah , Nanduri Lahiri Kanth , Ehrl Carolin , Maneck Matthias , Husemann Yves , Klein Christoph A.
Published: May 2015

Accumulating evidence indicates that tumor cells spread to distant sites much earlier than previously thought. The analysis of the BALB-neuT transgenic mouse model of breast cancer revealed that the relative number of disseminating cancer cells is highest at early stages of tumorigenesis. To unravel the mechanisms of early dissemination we performed a stage-dependent analysis of gene expression patterns in BALB-neuT mice. At the stage of atypical hyperplasia (ADH) gene expression profiles differed substantially from advanced tumors and lung metastases. We identified an ADH-specific gene expression signature and found that among the several hundred differentially expressed genes, many of them are regulated by sex hormones. We investigated whether this expression pattern might be linked to the propensity to disseminate. For this we established a surrogate signature for the ADH-specific pattern comprising five genes and tracked the regulating role of hormones in vitro or in vivo. Our results indicate that sex hormones act indirectly on mammary stem and progenitor cells to induce dissemination and metastasis and that hormone nuclear receptors are down-regulated in advanced tumors. Thereby, large tumors become less capable of disseminating metastatic cells.

Citation Format: Hedayatollah Hosseini, Lahiri Kanth Nanduri, Carolin Ehrl, Matthias Maneck, Yves Husemann, Christoph A. Klein. Molecular mechanisms of early metastatic dissemination in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A092.
Abstract A096: MT-SP2/TMPRSS4 upregulates uPA gene expression through JNK signaling activation to induce cancer cell invasion
Authors: Lee Yunhee , Min Hye-Jin , Lee Hana , Zhao Xue-Feng , Park Young-Kyu , Kim Semi
Published: May 2015

The invasive nature of tumor cells is critical for cancer metastasis. Urokinase-type plasminogen activator (uPA) is a well-known serine protease involved in normal tissue remodeling, such as wound healing, and in pathological events, such as invasion and metastasis. Increased levels of uPA correlate with invasive properties and poor prognosis in breast, lung, stomach, bladder, colon, prostate and ovarian cancers. MT-SP2/TMPRSS4 is a novel type II transmembrane serine protease that is highly expressed in pancreatic, colon, and other cancer tissues. Previously, we demonstrated that MT-SP2/TMPRSS4 mediates tumor cell invasion, migration, and metastasis. However, the mechanisms by which MT-SP2/TMPRSS4 contributes to invasion are not fully understood. Here, we demonstrated that MT-SP2/TMPRSS4 induced the transcription of the uPA gene through activating the transcription factors Sp1, Sp3, and AP-1 in mainly a JNK-dependent manner and that the induction of uPA was required for MT-SP2/TMPRSS4-mediated cancer cell invasion and signaling events. In addition, the uPA receptor was involved in MT-SP2/TMPRSS4-induced signaling activation and subsequent uPA expression probably through its association with TMPRSS4 on the cell surface. Immunohistochemical analysis showed that uPA expression was significantly correlated with MT-SP2/TMPRSS4 expression in human carcinomas. These observations suggest that MT-SP2/TMPRSS4 is an important regulator of uPA gene expression; the upregulation of uPA by TMPRSS4 contributes to invasion and may represent a novel mechanism for the control of invasion.

Citation Format: Yunhee Lee, Hye-Jin Min, Hana Lee, Xue-Feng Zhao, Young-Kyu Park, Semi Kim. MT-SP2/TMPRSS4 upregulates uPA gene expression through JNK signaling activation to induce cancer cell invasion. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A096.
Abstract A108: Distinct immune suppressive myeloid cell populations are induced by hypoxic mammary tumors and differentially promote metastatic tumor growth
Authors: Hamilton Melisa J. , Bosiljcic Momir , LePard Nancy E. , Harbourne Bryant T. , Krystal Gerald , Bennewith Kevin L.
Published: May 2015

Some primary tumors induce the accumulation of myeloid cells in distant tissues, and a role for these cells in promoting metastasis is emerging. However, the identity and function of these myeloid cells in metastatic breast cancer is unclear. Using transplantable and spontaneous metastatic mammary tumor models, we have found that immune suppressive CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs) and CD11b+F4/80+Gr1- macrophages (MΦs) accumulate in the spleens and lungs of tumor-bearing mice due to proteins secreted by poorly oxygenated (hypoxic) cells in primary tumors. We also found that immunosuppressive MDSCs remain elevated in the lungs for several weeks after surgical resection of the primary tumor, and that these MDSCs profoundly enhance subsequent pulmonary metastatic growth.

To decrease MDSC levels in tissues, we therapeutically targeted hypoxic tumor cells or used all-trans retinoic acid (ATRA) to differentiate immature MDSCs into mature MΦs. Targeting hypoxic tumor cells or ATRA treatment both decreased MDSC levels in tissues, although ATRA-treated mice had more MΦs and significantly more lung metastases than untreated mice. Consistent with these data, we found that MΦs were 30-fold more potent suppressors of T cell-mediated immune responses than MDSCs on a per cell basis, and that MΦs and MDSCs suppress via different reactive oxygen species (ROS)-mediated mechanisms.

Taken together, these data suggest that hypoxia-mediated accumulation of MDSCs in the lungs can have long-lasting implications for the growth of secondary metastatic tumors after treatment. However, due to the immune suppressive function of MΦs, our data caution against inducing the terminal differentiation of MDSCs into MΦs for breast cancer treatment. These studies support the development of therapies to enhance anti-tumor immunity by targeting hypoxic tumor cells, MDSCs, and MΦs for the treatment of metastatic breast cancer.

Citation Format: Melisa J. Hamilton, Momir Bosiljcic, Nancy E. LePard, Bryant T. Harbourne, Gerald Krystal, Kevin L. Bennewith. Distinct immune suppressive myeloid cell populations are induced by hypoxic mammary tumors and differentially promote metastatic tumor growth. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A108.
Abstract B004: Expansion of lineage negative, CD24high, CD61+ mammary cells is an early step in mammary tumorigenesis in NRL-TGFalpha and MMTV-c-neu but not MMTV-c-myc models of luminal breast cancer
Authors: Zhdankin Olga , Bomier Melanie , Parke Donna , Holy Jon , Rose-Hellekant Teresa
Published: May 2015

Our goal was to define the balance of normal, healthy mammary epithelial cell subpopulations, including putative stem, progenitor and mature cells, in mouse models of luminal breast cancer prior to tumor development. We isolated mammary cells using flow cytometric analysis, first by removing immune cells through negative lineage selection followed by labeling of remaining cells with CD24, CD61 and CD49f fluorescently tagged antibodies. We distinguished the presence of cell subpopulations and determined relative fractions of cells with expression patterns of enriched presumptive luminal progenitor cells (CD24 high, CD61positive), mature luminal cells (CD24high, CD61positive) and mammary stem cells (CD24 medium, CD49f high). Mammary glands from 3-4 month TGFalpha mice contained similar fractions of mammary cell subpopulations as wild type mice but at 7-8 month TGFalpha mice had an expanded CD24 high CD61positive fraction associated with hyperplasias and tumors. Four-month-old c-neu mice had expanded CD24 medium, CD49f high cell fractions and by the time tumors developed, both nontumorous glands and tumors also displayed an expanded CD24 high, CD61+ cell fraction. The cell surface marker expression pattern of mammary cells was unique in c-myc mice in that CD24 high (luminal) versus CD24 medium (myoepithelial) populations were not distinguishable at any time point. Our results indicate that early phases of tumorigenesis can be recognized by the disproportion presence of otherwise “normal” epithelial cell subpopulations or by the presence of novel subpopulations.

Citation Format: Olga Zhdankin, Melanie Bomier, Donna Parke, Jon Holy, Teresa Rose-Hellekant. Expansion of lineage negative, CD24high, CD61+ mammary cells is an early step in mammary tumorigenesis in NRL-TGFalpha and MMTV-c-neu but not MMTV-c-myc models of luminal breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B004.
Abstract B009: A role for receptor tyrosine kinase crosstalk in a Met-dependent model of triple-negative breast cancer
Authors: Sung Vanessa , Knight Jennifer F. , Park Morag
Published: May 2015

Triple-negative (TN) breast cancers, which include the basal-like and claudin-low subtypes, account for up to 20% of breast cancer cases. TN breast cancers lack expression of therapeutic targets HER2 and estrogen receptors and are correlated with poor prognosis. In human breast cancer, elevated levels of MET are correlated with TN subtypes and poor outcome. The Met receptor tyrosine kinase (RTK) is a cell surface protein that, upon activation by its ligand hepatocyte growth factor (HGF), initiates a program of cell survival, migration, and invasive growth. To investigate the role of Met in breast tumorigenesis, we have used two mouse models in which mammary specific expression of an oncogenic variant of Met is driven by the MMTV promoter (Metmt). Metmt mice develop mammary tumors with a long latency and display features of basal-like breast cancer. As loss of function mutations in TP53 are found in ~80% of TN breast cancers, we have also generated Metmt mice with conditional deletion of Trp53 in the mammary gland (Metmt;p53-), which results in accelerated tumorigenesis and gene expression profiles that more closely resemble that of the claudin-low subtype of TN breast cancer.

The present work aims to elucidate how Met promotes mammary tumor development and whether this involves regulation of tumor-initiating cells (TICs). TICs have emerged as a key concept in prevailing models of tumor development, and are thought to drive tumorigenesis as well as contribute to disease relapse. To study TICs in our mouse models, we employed the sphere-forming assay, which enriches for TICs based on their stem-like ability to survive, propagate, and self-renew in suspension as spheroid structures (tumorspheres). Tumorspheres cultured from both tumor models express constitutively active Met. Upon treatment with Met inhibitor, Metmt tumorspheres are drastically reduced in both number and size. In contrast, Metmt;p53- tumorspheres are insensitive to Met inhibition, suggesting that other signals compensate for the loss of Met activity. It has been shown that Met can crosstalk with other RTKs such as EGFR. Therefore we hypothesize that activation of an alternative RTK signalling pathway is compensating for loss of Met signalling in Metmt;p53- tumorspheres.

The molecular events that lead to TN breast cancers are poorly understood. Validating a role for Met in TICs and identifying key cooperating pathways involved in the pathogenesis of triple negative breast cancers could provide information for new therapeutic targets.

Citation Format: Vanessa Sung, Jennifer F. Knight, Morag Park. A role for receptor tyrosine kinase crosstalk in a Met-dependent model of triple-negative breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B009.
Abstract B013: Neuregulin signaling in development and transformation of the luminal breast epithelium
Authors: Vaught David B. , Hicks Donna , Cook Rebecca
Published: May 2015

The goal of these studies is to determine how combined loss of ErbB3 and ErbB4 impact the normal and transformed luminal population of the breast epithelium. Although little is known regarding the role of ErbB3 in luminal breast cancers, and even less about ErbB4, we have shown that ErbB3 and ErbB4 (the neuregulin receptors) are required for growth and survival of the two major luminal mammary epithelial cell types, the ductal luminal mammary epithelium, and the milk-producing alveolar mammary epithelium. However, as both ErbB3 and ErbB4 are capable of binding to neuregulins and heterodimerizing with other ErbB family members, there is evidence that ErbB4 may compensate for loss of ErbB3, and vice versa. Further, given that ErbB3 and ErbB4 are uniquely required within the luminal breast epithelium during phases of extreme physiological proliferation (i.e., puberty and pregnancy, respectively) it is likely that the neuregulin receptors drive cell growth and survival of breast cancers derived from the luminal breast epithelium. We hypothesize that elimination of NRG signaling by combined loss of ErbB3 and ErbB4 would prevent expansion of the mammary epithelium in response to physiological cues (i.e. pregnancy) and pathological cues (oncogene expression). Our early studies demonstrate loss of ErbB3 expansion of the alveolar epithelium during pregnancy, decreased expression of genes encoding milk proteins, and decreased milk delivery to nursing pups. This is similar to what is seen in ErbB4-deficient mammary glands. We are currently studying the ErbB3-dependnet molecular mechanisms required for expansion of the alveolar epithelium during pregnancy, and are generating mice that lack ErbB3 and ErbB4 in the alveolar mammary epithelium. We anticipate that combined gene targeting of ErbB3 and ErbB4 will cause a more pronounced lactational deficit.

Citation Format: David B. Vaught, Donna Hicks, Rebecca Cook. Neuregulin signaling in development and transformation of the luminal breast epithelium. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B013.
Abstract B025: The role and regulation of SOX7 in breast cancer
Authors: Stovall Daniel B. , Wan Meimei , Miller Lance D. , Cao Paul , Zhang Qiang , Stampfer Martha , Liu Wennuan , Xu Jianfeng , Sui Guangchao
Published: May 2015

Loss of tumor suppressors by both epigenetic silencing and genetic deletion contributes to the development and progression of breast cancer. SOX7 is an important developmental transcription factor and its downregulation has been reported in tumor tissues and cell lines of prostate, colon and lung cancers. Our current study demonstrates that SOX7 mRNA and protein expression are downregulated in breast cancer tissues and cell lines compared to adjacent normal tissues and nontumorigenic cells, respectively. Further, we show that both hypermethylation of the SOX7 promoter and microRNAs contribute to SOX7 downregulation. SOX7 silencing by shRNAs in nontumorigenic immortal breast cells leads to increased proliferation and invasion, and they form structures resembling that of breast cancer cells in a three-dimensional culture system. Conversely, ectopic SOX7 expression inhibits proliferation, and invasion of breast cancer cells in vitro and tumor growth in vivo. Importantly, we discovered that SOX7 transcript levels positively correlated with clinical outcome of 674 breast cancer patients. Collectively, our data suggest that SOX7 acts as a tumor suppressor in breast cancer. SOX7 expression is likely regulated by multiple mechanisms and potentially serves as a prognostic marker for breast cancer patients.

Citation Format: Daniel B. Stovall, Meimei Wan, Lance D. Miller, Paul Cao, Qiang Zhang, Martha Stampfer, Wennuan Liu, Jianfeng Xu, Guangchao Sui. The role and regulation of SOX7 in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B025.
Abstract B057: Treatment with anti-human GP88/progranulin antibody restores tamoxifen sensitivity to tamoxifen-resistant breast cancer cells
Authors: Serrero Ginette , Dong Jianping , Yue Binbin , Hicks David , Hayashi Jun
Published: May 2015

The 88 kDa glycoprotein GP88 (Progranulin, PCDGF, acrogranin) is the largest member of the granulin/epithelin family consisting of 7.5 repeats of a highly conserved 12-cysteine granulin/epithelin motif. Our laboratory demonstrated the role of GP88 as an autocrine growth and survival factor in breast cancer: 1) GP88 expression increases with tumorigenesis; 2) inhibition of GP88 expression by antisense transfection in MDA-MB-468 cells inhibited tumor formation in nude mice by 90%; 3) in ER+ breast cancer cells, GP88 stimulates proliferation and its overexpression confers estrogen independence; 4) GP88 is a strong survival factor that confers resistance to anti-estrogen and aromatase inhibitors in ER+ breast cancer; 5) GP88 is expressed in 80% invasive ductal carcinoma and 60% of ductal carcinoma whereas it is negative in benign lesions and normal mammary epithelial cells; 6) pathological studies with 530 cases of ER+ invasive ductal carcinoma (ER+ IDC) showed that GP88 tumor expression is a prognostic indicator of recurrence and death in early stage breast cancer patients with high GP88 tissue expression associated with a 4-fold increase in the risk of recurrence; 7) GP88 is secreted and can be detected in the serum of breast cancer patients at an increased level when compared to healthy subjects. Based on these results GP88 represents an ideal therapeutic and diagnostic target in breast cancer. We have characterized a neutralizing anti-GP88 monoclonal antibody that has been expressed in recombinant form and named AG1. AG1 inhibits GP88 biological effect such as migration and invasion of breast cancer cells in a dose-dependent fashion. Since GP88 is a prognostic factor of recurrence in ER+ IDC, the present study investigates the effect of AG1 on the tumor development and tamoxifen responsiveness of tamoxifen resistant ER+ breast cancer cell line (TamR) injected in nude mice. We show that AG1 alone inhibited tumor growth of TamR cells injected into nude mice while tamoxifen alone had moderate effect. Interestingly, AG1 administered in combination with tamoxifen, inhibited by more than 50% tumor formation of TamR cells.

These data suggest that inhibiting GP88 provide a novel and alternate pathway for restoration of tamoxifen sensitivity in ER+ breast cancer.

This works is supported by grant 2R44CA124179 and contract HHSN261201200060C from the National Cancer Institute.

Citation Format: Ginette Serrero, Jianping Dong, Binbin Yue, David Hicks, Jun Hayashi. Treatment with anti-human GP88/progranulin antibody restores tamoxifen sensitivity to tamoxifen-resistant breast cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B057.
Abstract B071: Targeting the antiapoptotic protein Mcl-1 in luminal B breast cancers
Authors: Williams Michelle M. , Fesik Steve , Hicks Donna , Cook Rebecca S.
Published: May 2015

In an effort to improve therapeutic tumor cell killing in luminal B breast cancers, we are investigating the combination of endocrine therapies with targeted inhibition of pro-survival proteins of the Bcl2 family, including Bcl2, Bcl-xL, and Mcl-1. Bcl2-family proteins are often overexpressed in breast cancers and are associated with tumor progression, therapeutic resistance, and poor patient survival. These proteins function by sequestering pro-apoptotic BH3-only proteins (BIM, BID, Noxa and Puma), thus inhibiting caspase-dependent apoptosis. We found Mcl1 gene amplification in 15/133 luminal B breast tumors (11%) curated through the Cancer Genome Atlas (TCGA), and Bcl2l1 (encoding Bcl-xL) gene amplification in 1/133 luminal B breast tumors, although Bcl2l1 mRNA was upregulated in 19/133 samples. Bcl2 was not amplified or overexpressed in TCGA-curated luminal B breast tumors. The BH3 mimetic ABT-263, which specifically binds Bcl2 and Bcl-xL, increased tumor cell killing in 3 out of 4 estrogen-deprived luminal B human breast cancer cell lines. However, ZR75-1 cells, which are Mcl1 gene amplified, were resistant to ABT-263. Further, Mcl-1 protein upregulation was induced in HCC-1428 and T47D cells treated with ABT-263, suggesting that cells may use Mcl-1 upregulation to partially mitigate the effects of Bcl-xL targeting with ABT-263. Mcl-1 knockdown using an shRNA approach, decreased cell growth and increased caspase-dependent apoptosis, and increased sensitivity to ABT-263 in 4 of the 4 cell lines tested, including ZR75-1 cells. We used long-term estrogen withdrawal (LTED) to model the sustained response of breast cancer cells to aromatase inhibitors (e.g., exemestane). As compared to parental breast cancer cell lines under estrogen withdraw conditions, LTED populations drastically increased protein levels of Mcl-1. Future experiments will be aimed at assessing the impact of Mcl-1 depletion on ABT-263-treated LTED populations. We predict that combined inhibition of Bcl-2, Bcl-xL and Mcl-1 will improve response of cells to estrogen deprivation. In summary, these preliminary studies suggest that BH3 mimetics targeting Bcl-2 family proteins may be therapeutically efficacious in endocrine-refractory luminal B breast tumors, and support future endeavors to generate BH3-mimetics specifically targeting Mcl-1.

Citation Format: Michelle M. Williams, Steve Fesik, Donna Hicks, Rebecca S. Cook. Targeting the antiapoptotic protein Mcl-1 in luminal B breast cancers. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B071.
Abstract B097: Innate immune response to cell death in the post-partum mammary gland increases malignancy of parity-associated mammary tumors
Authors: Stanford Jamie C. , FIngleton Barbara , Owen Phil , Cook Rebecca S.
Published: May 2015

Pregnancy-associated breast cancers (PABCs) are associated with decreased overall survival as compared to breast cancers not associated with pregnancy, due in large part to macrophage-dependent changes that occur in the mammary gland during post-lactational involution. We have used the MMTV-PyVmT spontaneous mouse mammary tumor model to demonstrate that, while tumor latency, growth rate and burden were similar in parous and nulliparous mice, metastasis of parity-associated mammary tumors was increased 17-fold over tumors from age-matched virgin nulliparous mice. Th2 cytokines produced in the tumor microenvironment (TME) correlate with increased tumor malignancy. We found profoundly upregulated expression of Th2 cytokines in parity-associated mammary tumors over tumors from nulliparous mice, including interleukin (IL)-4, IL-13, and IL-10. Serum harvested from parous mice induced tumor cell invasion to a greater extent than serum from nulliparous mice. MerTK, a receptor tyrosine kinase (RTK) of the Tyro-3/Axl/MerTK family expressed in M2c tissue macrophages and TAMs, suppresses Th1 cytokine production and promotes Th2 cytokine expression. MerTK expression was profoundly upregulated in parous mammary tumors during post-lactational involution, similar to previous findings of MerTK upregulation in normal mammary glands during involution. Although loss of MerTK did not affect latency or growth of parity-associated mammary tumors, we observed decreased metastasis and Th2 cytokine production in MerTK-deficient tumors. Serum from MerTK-deficient parous mice induced tumor cell invasion to a lesser extent than serum from parous wild-type mice. These results demonstrate that MerTK enhances malignancy of parity-associated mammary tumors, and may represent a therapeutic target to improve the outcome in PABC.

Citation Format: Jamie C. Stanford, Barbara FIngleton, Phil Owen, Rebecca S. Cook. Innate immune response to cell death in the post-partum mammary gland increases malignancy of parity-associated mammary tumors. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B097.
Abstract B115: Excessive milk production during breast feeding prior to breast cancer diagnosis is associated with increased risk for early events
Authors: Gustbée Emma , Anesten Charlotte , Markkula Andrea , Simonsson Maria , Rose Carsten , Ingvar Christian , Jernstrom Helena
Published: May 2015

Background: Breast feeding is a known protective factor against breast cancer. Breast feeding duration is influenced by hormone levels, milk production, and lifestyle factors. We aimed to investigate how breast feeding duration and milk production affect tumor characteristics and risk for early breast cancer events in women who subsequently developed breast cancer.

Methods: Between 2002 and 2008, 634 primary breast cancer patients in Lund, Sweden, took part in an ongoing prospective cohort study. Data were extracted from preoperative questionnaires, pathology reports, patients' charts and Swedish registries from 592 patients without preoperative treatment.

Results: Breast feeding duration ≥12 months of the first child was associated with higher frequency of ER+/PgR+ tumors (P=0.02). Median follow-up time was 4.9 years. Higher risk for early events was observed for breast feeding duration of first child >12 months (LogRank P=0.001), total breast feeding duration >12 months (LogRank P=0.004), as well as ‘excessive milk production’ during breast feeding of the first child (LogRank P=0.003). Patients with ‘almost no milk production’ had no events. In a multivariable model including both ‘excessive milk production’ and breast feeding duration of the first child >12 months, both were significantly associated with a two-fold risk for early events, adjusted HRs 2.19 (95% CI: 1.17-4.11) and 2.61 (1.06-6.38), respectively, adjusted for age, invasive tumor size, axillary lymph node involvement, ER and PgR status, age at first birth, time since last birth, smoking status, and BMI, while total breast feeding duration was not. ‘Excessive milk production’ was associated with a two-fold risk of early distant metastases, adjusted HR 2.41 (1.09-5.32), but not breast feeding duration.

Conclusion: ‘Excessive milk production’ during breast feeding was associated with higher risk for early events independent of tumor characteristics, while patients who reported ‘almost no milk production’ had no events. This finding stresses the need to consider host factors in the evaluation of prognostic markers.

Citation Format: Emma Gustbée, Charlotte Anesten, Andrea Markkula, Maria Simonsson, Carsten Rose, Christian Ingvar, Helena Jernstrom. Excessive milk production during breast feeding prior to breast cancer diagnosis is associated with increased risk for early events. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B115.
Abstract B117: Risk factors of second breast cancer among patients with ductal carcinoma in situ
Authors: Liu Ying , Colditz Graham
Published: May 2015

Background: Women with ductal carcinoma in situ (DCIS) are at increased risk of breast cancer in either ipsilateral or contralateral breasts. However, it is inconclusive about the factors predicting the risk of second breast cancer after DCIS.

Methods: We used US Surveillance, Epidemiology, and End Results data on women with first unilateral DCIS diagnosed between 1988 and 2009. Relative risks (RRs) were estimated using cox regression models to identify the factors associated with the risks of second DCIS and second invasive breast cancer (IBC).

Results: Of the 74,285 eligible DCIS patients, 6,140 (8.3%) had subsequent breast cancer during 8.5 years of follow-up (714 ipsilateral DCIS, 2,003 ipsilateral IBC, 997 contralateral DCIS, and 2,426 contralateral IBC). Patients <50 years (RR=1.45; 95% confidence interval (CI), 1.29-1.64), black patients (RR=1.60; 95% CI, 1.39-1.83), patients with comedo DCIS (RR=1.19; 95% CI, 1.07-1.32), and patients with poorly differentiated DCIS (RR=1.45; 95% CI, 1.15-1.82) were more likely to develop ipsilateral breast cancer. Solid histologic type was more strongly associated with increased risk of ipsilateral IBC (RR=1.49; 95% CI, 1.12-1.99). The risk of contralateral breast cancer was increased among black women (RR=1.33; 95% CI, 1.16-1.52) and was decreased among young women and women with comedo DCIS, which was more obvious for contralateral IBC.

Conclusion: The risk factors were different for second breast cancer in the ipsilateral breast and in the contralateral breast. Improved follow-up of young patients, black patients, patients with poorly differentiated DCIS, and patients with comedo or solid DCIS may reduce the risk of second IBC. Further investigations are needed to identify molecular features of DCIS that predict risk of second breast cancer and/or mediate racial and age differences in second cancer risk.

Citation Format: Ying Liu, Graham Colditz. Risk factors of second breast cancer among patients with ductal carcinoma in situ. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B117.
Abstract IA05: Understanding estrogen receptor transcription in breast cancer
Authors: Carroll Jason S.
Published: May 2015

Estrogen Receptor (ER) is the defining feature of luminal breast cancers, where is functions as a transcription factor. The traditional view of ER getting recruited to promoters of target genes is too simplistic. The recent discovery of ER-DNA interaction regions from ER+ breast cancer cell lines has revealed that ER rarely associates with promoter regions of target genes and instead associates with enhancer elements significant distances from the target genes. The genomic mapping of ER binding events also revealed the enrichment of DNA motifs for Forkhead factors. The Forkhead protein FOXA1 (HNF3a) was subsequently shown to bind to ~half of the ER binding events in the genome and was required for ER to maintain interaction with DNA. We have extended on these findings to explore ER and FoxA1 functional interactions in breast cancer, with a specific focus on changes in binding dynamics that occur during endocrine resistance. To this end, we have established transcription factor mapping approaches (ChIP-seq) in primary tumor material, to investigate differential ER/FoxA1 binding that occurs during tumor progression. We have functionally explored underlying factors that contribute to altered transcription factor binding and activity. In addition, we have recently established a method for rapid unbiased discovery of protein interactomes, which we have applied to discover ER and FoxA1 associated proteins. We find unexpected interactions between ER and additional nuclear receptors in ER+ breast cancer, which appear to be important modulators of cellular growth and endocrine response. These findings help delineate the complexes that influence ER transcriptional activity and ultimately impinge on tumor progression and drug sensitivity.

Citation Format: Jason S. Carroll. Understanding estrogen receptor transcription in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr IA05.
Abstract IA10: Using lineage tracing and clonal analysis to unravel mammary gland expansion and cancer initiation
Authors: Keymeulen Alexandra Van , Lee May Yin , Ousset Marielle , Blanpain Cédric
Published: May 2015

We developed novel lineage tracing approaches in mice to decipher the cellular hierarchy of the mammary epithelium during development, adulthood, pregnancy and lactation and to study the cell of origin of different types of breast cancers. Knowing that luminal cells specifically express the keratins K8 and K18, while myoepithelial cells express K5 an K14, we generated two inducible CRE recombinase (CREER) mice expressed in the luminal cells, under the control of K8 and K18 promoters to target luminal cells. To target myoepithelial cells, we used mice expressing the CREER under the control of K5 promoter, as well as the K14rtTA-TetOCRE mice. We demonstrated that the mammary gland initially develops from multipotent embryonic progenitors expressing K14, which give rise upon differentiation to both myoepithelial and luminal cells. However, during puberty and homeostasis, as well as during pregnancy and lactation, the expansion and the maintenance of luminal cells is ensured by the presence of luminal unipotent SCs, while the expansion and maintenance of myoepithelial cells is ensured by the presence of myoepithelial unipotent SCs, rather than being maintained by rare multipotent SCs. We also demonstrated that transplantation assays, while extremely informative about the differentiation potential of tissue specific SCs, can be misleading in extrapolating the differentiation potential of SCs under physiological conditions.

While the different genes implicated in inherited and sporadic breast cancers have been identified, the cellular origin of the different types of breast cancers remains elusive. Mutations in the cancer suppressor genes BRCA (BRCA1 and BRCA2) account for the majority of inherited breast cancers, and are associated with basal-like tumors. Oncogenic mutations in PIK3CA are found in 20 to 40% of invasive breast cancers and are associated with luminal tumors. To determine the cell of origin of breast cancers, we use the K8CREER mice to introduce oncogenic mutations specifically in luminal cells, while we use the K5CREER mice to introduce the mutations in basal cells. We target deletion of Brca1 and p53 to recapitulate basal-like breast cancers, while expression of the oncogene PIK3CA is used to recapitulate luminal-like breast cancers. Our results show that the differentiation of breast tumors can be misleading to extrapolate their cellular origin and that cell fate changes occur during breast cancer initiation.

Citation Format: Alexandra Van Keymeulen, May Yin Lee, Marielle Ousset, Cédric Blanpain. Using lineage tracing and clonal analysis to unravel mammary gland expansion and cancer initiation. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr IA10.
Abstract A03: Immunoglobulin heavy chain usage in canine CLL
Authors: Burnett Robert , George Stacey , Mancha Serena , Bromerek Julia , Avery Anne
Published: May 2015

Canine B cell chronic lymphocytic leukemia resembles human CLL in presentation and clinical outcomes. The disease is indolent (median survival greater than 1000 days) and presents in older dogs (median age = 10.8 years). Major differences between the human and canine disease include immunophenotype (canine B cell CLL does not express CD5) and a gender ratio in the dog that is 1:1. Risk factors for canine B cell CLL have not been identified, but three breeds are more frequently represented amongst CLL cases than in the general population of dogs with confirmed or suspected lymphoproliferative disease of any type; Boxers, Shih-tsu dogs and English Bull dogs. Remarkably, the breed which most frequently develops a variety of lymphoproliferative disorders, the Golden Retriever, is virtually absent from the population of canine CLL patients. This breed predilection suggests that as in people, genetic factors contribute significantly to risk. We hypothesized that canine B cell CLL would be a useful model for uncovering genetic risk factors for the disease, and here we report initial characterization of this model by examining immunoglobulin V gene usage and mutation status. Our findings are: 1) 34% of dogs with CLL had unmutated IgVH genes, as defined by a difference of greater than 2% from the available germline sequence, 2) While the canine genome has 85 IgH V gene segments (43 pseudogenes, 42 functional genes), almost half (42%) of the CLL cases with unmutated IgH genes used a single V gene segment, VH41; Only 9% of non-neoplastic B cells utilize VH41, and 5% of CLL cases with mutated genes use VH41; 3) All animals of the Boxer breed had unmutated IgH genes; 4) canine VH35 was used in 29% of cases with somatic hypermutation, but was not found in unmutated CLL nor in the normal canine B cell repertoire. The striking breed association and restricted V gene usage suggest that certain dog breeds such as the Boxer could provide a useful model for investigation of genetic factors leading to B cell CLL in both humans and dogs.

Note: This abstract was not presented at the conference.

Citation Format: Robert Burnett, Stacey George, Serena Mancha, Julia Bromerek, Anne Avery. Immunoglobulin heavy chain usage in canine CLL. [abstract]. In: Proceedings of the AACR Special Conference: The Translational Impact of Model Organisms in Cancer; Nov 5-8, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(11 Suppl):Abstract nr A03.
Abstract A06: Interspecific recombination between orthologous human and mouse BAC clones in E. coli: Exploring scalable humanization of cancer-relevant genes in the mouse genome
Authors: Leidy-Davis Tiffany , Bergstrom David E.
Published: May 2015

Our interests lie in humanizing specific regions of the mouse genome using large segments of human DNA with extents of 10s to 100s of kilobase pairs. To that end, we have undertaken a series of projects to transfer large segments of human DNA, from human BAC clones, into the orthologous region of corresponding mouse BAC clones using— (1), traditional recombineering methods; (2), recombinase-mediated cassette exchange (RCME); and (3), a novel technology that we call trans- or trimolecular-recombineering. In each instance the goal is to place human DNA within the larger context of homologous BAC-derived mouse arms in E. coli.

Completed constructs will be used to drive homologous recombination in mouse embryonic stem (ES) cells with positive selection imparted at each end of the transferred human segment using dual, recombinase recognition site-flanked, selectable marker cassettes. Properly targeted ES cells will be used to develop viable mouse strains carrying the humanized segments. Selection cassettes will be removed by crossing to mouse strains with germline expression of the appropriate recombinases. All experiments have been designed to maintain a fixed genetic background from community-standard C57BL/6 strains. Our poster presentation details the specifics of our projects and describes progress to date.

This research is supported by National Cancer Institute Grant Number 5P30CA034196-28.

Citation Format: Tiffany Leidy-Davis, David E. Bergstrom. Interspecific recombination between orthologous human and mouse BAC clones in E. coli: Exploring scalable humanization of cancer-relevant genes in the mouse genome. [abstract]. In: Proceedings of the AACR Special Conference: The Translational Impact of Model Organisms in Cancer; Nov 5-8, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(11 Suppl):Abstract nr A06.
Abstract A27: BLM overexpression promotes tumorigenicity in an azoxymethane/dextran sulfate (AOM/DSS) murine model of intestinal cancer
Authors: Ebede Kenechi , McIlhatton Michael , Hankey William , Groden Joanna
Published: May 2015

The role of genomic instability in colorectal cancer susceptibility is well established by studies of hereditary non-polyposis colon cancer (HNPCC), its associated disruption of DNA mismatch repair, and other DNA repair deficiencies that predispose to colon cancer. DNA repair deficiency that results in loss of capacity to maintain the genome leads to increased mutation or chromosome instability that in turn increases tumor formation. In some recent experiments using mouse models of cancer, deletion of genomic housekeeping genes promoted tumorigenesis. The Blm gene encodes a RecQ helicase that represses aberrant homologous recombination. Previous experiments using ApcMin/+ mice showed that a heterozygous Blm mutation increased intestinal tumor formation and tumor dysplasia. Conversely, mice over-expressing BLM displayed more than a 50% reduction of intestinal tumor number compared to wild-type controls.

In order to isolate the effect of a Blm mutation on tumorigenicity, we used C57Bl/6 mice treated with azoxymethane and dextran sulfate to induce polyp formation. We predicted that mice with homozygous deletion of Blm would show an increase in tumor formation compared to wild-type mice, and transgenic mice over-expressing BLM would display fewer polyps. After treating our mice for 12 weeks and sacrificing them between 155 and 165 days of age, we found that mice with a complete deletion of Blm displayed a decrease in polyp formation compared to wild-type controls (3.0 polyps v. 5.5 polyps, p = 0.004). Transgenic mice over-expressing BLM in this model showed an increase in median polyp formation compared to wild-type controls (8.5 polyps v. 5.5 polyps, p = 0.01). Ongoing experiments will clarify the mechanism by which Blm promotes tumorigenesis in this mouse model of colon cancer.

Citation Format: Kenechi Ebede, Michael McIlhatton, William Hankey, Joanna Groden. BLM overexpression promotes tumorigenicity in an azoxymethane/dextran sulfate (AOM/DSS) murine model of intestinal cancer. [abstract]. In: Proceedings of the AACR Special Conference: The Translational Impact of Model Organisms in Cancer; Nov 5-8, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(11 Suppl):Abstract nr A27.