bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P6-02-07: Targeting triple-negative breast cancer with fibroblast growth factor receptor 2 allosteric inhibitor RPT835
Authors: Tjulandin Sergey A , Tsimafeyeu Ilya V , Byakhov Mikhail Y , Yin Wei , Ludes-Meyers John , Daeyaert Frits
Published: May 2015

Background: FGFR2 is amplified in 4% of triple-negative breast cancers (TNBC). In addition, the mRNA expression levels of FGFR2 were significantly increased in amplified vs nonamplified tumor samples, suggesting a potential role for FGFR2 in TNBC (Turner et al. 2010). We evaluated efficacy of allosteric inhibition of FGFR2 in high- and low-expressing TNBC xenografts.

Methods: Immunocompromised mice were used for xenotransplantation of FGFR2 high-expressing TNBC cells (SUM52PE) or FGFR2 low-expressing TNBC cells (HS578T). Forty animals with measurable tumors were selected on day 10 and randomized into treatment groups (low-molecular weight allosteric inhibitor RPT835, 30 mg/kg; gavage, daily) or vehicle (water; gavage, daily). Measurements of tumor volume (mm3) were performed by digital calipers every 3 days during 40 days after tumor inoculation.

Results: RPT835 significantly inhibited aggressive growth of SUM52PE tumor xenograft (P<0.0001). At study day 31, mean tumor volumes (± SE) were 2712.2±37 mm3 in the vehicle group, and 1080.7±49 mm3 in the study group. In addition, animals of the study group received RPT835 from day 31 to day 40 with disease stabilization (no differences in tumor volume between days 31 and 40, P=0.167). The tumor growth curve shows a nearly exponential increase in median tumor volume up to day 31 in the vehicle group and a high rate of slow growing tumors up to day 40 in the study group. In the HS578T xenograft study differences in tumor volume between study and control groups were weak at day 31 (mean tumor volumes ± SE, 703±89.1 mm3 vs. 1053±179.8 mm3, respectively; P<0.001) and at day 40 (1104±162.2 mm3 vs. 1592±335 mm3; P=0.01).

Conclusions: The allosteric FGFR2 inhibitor RPT835 significantly impacts on growth of FGFR2-expressing TNBC.

Citation Format: Sergey A Tjulandin, Ilya V Tsimafeyeu, Mikhail Y Byakhov, Wei Yin, John Ludes-Meyers, Frits Daeyaert. Targeting triple-negative breast cancer with fibroblast growth factor receptor 2 allosteric inhibitor RPT835 [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-02-07.
Abstract P6-03-02: Functional genomic screening identifies USP11 as a novel therapeutic target in breast cancer
Authors: O'Connor Darran P , Dwane Lisa , O'Connor Aisling E , Dirac Annette M , Bernards Rene , Gallagher William M
Published: May 2015

The estrogen receptor (ER) is the principal driver of growth and differentiation in breast cells and de-regulated receptor function is a key feature of almost 75% of breast cancers. Here, we investigated the role of de-ubiquitinating enzymes (DUBs), which act to remove ubiquitin moieties from proteins, in regulating the transcriptional activity of ER in breast cancer.

To identify DUBs involved in the regulation of ER transcriptional activity, we performed an RNAi loss-of-function screen using a library of shRNA vectors targeting all known human DUB genes (108 genes/432 shRNAs in total). We found that suppression of a number of DUBs markedly repressed or enhanced the activity of an estrogen-response-element (ERE) luciferase reporter to estradiol (E2). In particular, suppression of the BRCA2-associated DUB, USP11, was found to down-regulate ERα transcriptional activity (both in the presence and absence of E2), as demonstrated by a pronounced decrease in estrogen-response element (ERE) luciferase reporter activity. Subsequent validation of the screen using multiple individual hairpins and ZR-75-1 stable USP11 knockdown cells confirmed the suppression of ERE-reporter activity and further revealed a notable reduction in expression of the endogenous ER target genes TFF1 and PgR following USP11 knockdown. In vitro phenotypic analysis also revealed a global decrease in cell survival, decreased ERK and AKT phosphorylation and increased sensitivity to DNA-damaging agents in USP11 knockdown cell lines compared to non-targeting controls.

In silico analysis of publically available breast cancer gene expression datasets revealed a highly significant association between high USP11 mRNA levels and poor prognosis. We observed a highly significant correlation between high expression of USP11 mRNA in ER positive patients and poor overall survival (OS)(HR 1.51, CI 1.07-2.14, p=0.018) and distant metastasis-free survival (DMFS)(HR 1.35, CI 1.04-1.73, p=0.023). This correlation was also significant in ER positive patients who had received endocrine therapy (OS, HR 3.4, CI 1.2-9.81, p=0.014), DMFS, HR 2.16, CI 1.23-3.8, p=0.0083). These results suggest a role for USP11 in driving cellular growth and identify USP11 as a rationale and novel therapeutic target in breast cancer.

Citation Format: Darran P O'Connor, Lisa Dwane, Aisling E O'Connor, Annette M Dirac, Rene Bernards, William M Gallagher. Functional genomic screening identifies USP11 as a novel therapeutic target in breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-03-02.
Abstract P6-03-09: Targeting the c-myc/E2F1 pathway in TNBC promotes a DNA damage dependent synthetic lethality
Authors: Carey Jason P , Keyomarsi Khandan
Published: May 2015

The c-myc/E2F1 pathway is highly upregulated in TNBC and dictates increased genomic instability, a higher frequency of relapse and poor overall survival. C-myc is a potent oncogene with overexpression activity that influences several pathways including metabolism, DNA replication, DNA damage, cell cycle and apoptosis. The essential role of c-myc in normal cells has made therapeutic intervention elusive. However the role of c-myc influencing cell cycle progression has demonstrated that CDK inhibition downregulates c-myc expression in TNBC breast cancer cells. We hypothesize that CDK inhibition downregulates c-myc expression resulting in an accumulation of DNA damage thus increasing the susceptibility of TNBC cells to PARP inhibition. A panel of TNBC cell lines was assessed for c-myc/E2F1 pathway expression and downregulation in the presence of CDK inhibitor Dinaciclib. An MTT-based High Throughput Survival Assay (HTSA) was utilized to assess growth inhibition response to drug treatment in TNBC cells. FACS analysis was performed on Dinaciclib treated TNBC cell lines to asses cell cycle response to CDK inhibition. DNA damage and Homologous Recombination DNA repair was assessed by γH2AX, BRCA1, RAD51 foci formation by immunofluorescence. Lentiviral knockdown of c-myc, E2F1, BRCA1 and RAD51 were performed to assess susceptibility to PARP inhibition. Combination treatment of Dinaciclib + PARP inhibitor MK4827 was assessed via combination index values calculated by Calcusyn. CDK inhibition resulted in downregulation of both c-myc and E2F1 in all TNBC cells. The pan-CDK inhibitor Dinaciclib universally inhibited proliferation in all TNBC cell lines in the presence of the drug however drug removal allowed TNBC cells to recover a normal proliferative profile. Dinaciclib induction increased γH2AX foci formation while decreasing BRCA1 and RAD51 foci formation resulting in an increase in DNA damage induced cell death that correlated with c-myc downregulation. CDK inhibition correlated with downregulation of c-myc/E2F1 target genes. Lentiviral knockdown of c-myc and not E2F1 induced susceptibility to PARP inhibitor MK4827. Combination CDK + PARP inhibitor resulted in a dose dependent synthetic lethal increase in PARP inhibitor efficacy in both BRCA1 mutant and wild-type cells. Together these results suggest that c-myc downregulation via CDK inhibition in combination with PARP inhibition may pose a novel combination therapy for TNBC patients.

Citation Format: Jason P Carey, Khandan Keyomarsi. Targeting the c-myc/E2F1 pathway in TNBC promotes a DNA damage dependent synthetic lethality [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-03-09.
Abstract P6-05-03: CD4 Th1 cytokines and HER-2/HER-3 blockade induces tumor senescence in breast cancer
Authors: Rosemblit Cinthia , Czerniecki Brian J
Published: May 2015

Background: HER-2 a molecular oncodriver in breast tumorigenesis is over expressed in 25% of human breast cancers, and its expression correlates with enhanced tumor aggressiveness. While targeted therapies have improved outcomes many patients become resistant or recur. We have recently established a progressive loss in anti-HER-2 CD4 Th1 responses during disease progression and is associated with outcomes. The pleiotropic Th1 cytokines IFN-γ and TNF-α have diverse effects on tumor epithelial cells. In this study we sought to determine whether these Th1 cytokines induce senescence of HER-2 expressing breast cancer cells and assess the impact of IFN-γ and TNF-α with simultaneous HER-2 and HER-3 blockade.

Results: All breast cancer cell lines tested express IFN-γ and TNF-α receptors measured by western blot analysis. The high and intermediate HER-2 expressing cells are sensitive to tumor senescence induction when treated with combinations of IFN-γ and TNF-α in a dose dependent manner. Low HER-2 expressing cells were less sensitive to senescence induction as measured by positive β-galactosidase activity and the expression of p15INK4b and p16INK4a by western blot. Addition of IFN-γ and TNF-α treatment to HER-2-depleted cells by RNAi resulted in an increase senescent phenotype and was increased further when the cells were double HER-2- and HER-3-depleted. To determine whether CD4 Th1 mediated effects on high HER-2 human breast cancer cell lines, we co-cultured increasing number of HER-2 antigen-primed CD4+ T cells with high HER-2 human breast cancer cells in a transwell cell culture system. This resulted in a dose-dependent senescence of breast cancer cells compared with CD4+ T cells primed either with immature dendritic cells (DC) or mature DC plus irrelevant (Class II BRAF) peptide. In addition, SK-BR-3 breast cancer cells incubated with the supernatant of the CD4+ T cells-immature DC or mature DC co-culture demonstrated similar results. CD4+ Th1-elaborated cytokines IFN-γ and TNF-α in the supernatants were confirmed using ELISA. Blocking antibodies against IFN-γ and TNF-α demonstrated reduced senescence induction.

Conclusions: Our results establish a role for IFN-γ and TNF-α in inducing tumor senescence in breast cancer. An effective CD4 Th1 responses combined with HER-2 and HER-3 blockade can significantly drive tumor senescence in breast cancer that can be explored as treatment to effectively eliminate residual breast cancer cells and prevent recurrence.

Citation Format: Cinthia Rosemblit, Brian J Czerniecki. CD4 Th1 cytokines and HER-2/HER-3 blockade induces tumor senescence in breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-05-03.
Abstract P6-08-20: Prognostic significance of the interferon metagene in node-negative breast cancer depends on the molecular subtype
Authors: Schmidt Marcus , van de Sandt Leonie , Edlund Karolina , Sicking Isabel , Battista Marco , Heimes Anne-Sophie , Lebrecht Antje , Hoffmann Gerald , Gehrmann Mathias , Rahnenführer Jörg , Hengstler Jan G
Published: May 2015

Background: Interferons are crucial for adaptive immunity and play an important role as central coordinators of tumor-immune system interactions. We examined the subtype specific prognostic significance of an interferon (IFN) metagene in node-negative breast cancer.

Methods: Using microarray based gene-expression data, we identified co-regulated genes related to biological processes. After hierarchical clustering, we defined an interferon (IFN) metagene which was composed of 36 interferon-stimulated genes. The subtype specific prognostic role of the IFN metagene was analysed in four previously published cohorts (Mainz, Rotterdam, Transbig, Yu) of node-negative breast cancer patients not treated with adjuvant therapy (n=824). A meta-analysis of previously published cohorts was performed using a random effects model. Prognostic significance of the IFN metagene for metastasis-free survival (MFS) was examined in different molecular subtypes: luminal A (ER+/HER2-/aurora kinase A [AURKA]low, luminal B (ER+/HER2-/AURKAhigh), basal-like (ER-/HER2-), and HER2+.

Results: Prognostic significance of the IFN metagene was restricted to the HER2+ positive molecular subtype (HR 0.50, 95% CI 0.28-0.88, P=0.0056). Prognostic effects were not seen in luminal A (HR 1.00, 95% CI 0.65-1.53, P=0.8819), luminal B (HR 1.00, 95% CI 0.76-1.32, P=0.9770) or basal-like (HR 0.87, 95% CI 0.66-1.15, P=0.3282) carcinomas of the breast.

Conclusions: The prognostic significance of the interferon metagene in node-negative breast cancer is subtype specific and confined to the HER2+ molecular subtype. A higher expression of the IFN metagene is associated with improved outcome in HER2+ breast cancer.

Citation Format: Marcus Schmidt, Leonie van de Sandt, Karolina Edlund, Isabel Sicking, Marco Battista, Anne-Sophie Heimes, Antje Lebrecht, Gerald Hoffmann, Mathias Gehrmann, Jörg Rahnenführer, Jan G Hengstler. Prognostic significance of the interferon metagene in node-negative breast cancer depends on the molecular subtype [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-08-20.
Abstract P6-09-05: Value of adding single-nucleotide polymorphism panel markers to phenotypic algorithms of breast cancer risk
Authors: Dite Gillian , Allman Richard , Hopper John L
Published: May 2015

Currently, breast cancer risk prediction algorithms incorporate phenotypic risk factors, including age, family history, reproductive history and benign breast disease.

Since 2007, genome-wide association studies have identified a growing number of single-nucleotide polymorphisms (SNPs) that are associated with an increased risk of breast cancer. While no single SNP is very informative on its own, a polygenic approach to genetic screening could improve estimates of individual risk, creating the possibility of screening strategies individually tailored to each woman.

We studied cases and controls recruited to the Australian Breast Cancer Family Registry, to investigate whether a SNP risk score derived from a panel of 77 SNPs can improve risk estimates obtained from the commonly used breast cancer risk prediction models (BCRAT, IBIS, BRCAPRO and BOADICEA).

SNP risk scores were calculated using previously published Odds Ratios (ORs) and risk-allele frequencies based on the assumption of independence of additive risks on the log OR scale. SNP risk scores were calculated by multiplying adjusted risk scores for each of the SNPs. Combined risk scores were calculated by multiplying the SNP risk score and the algorithm derived risk scores, under the assumption of independence.

Overall, the inclusion of data on 77 SNPs improved the area under the receiver operating characteristic curve (AUC) for all of the breast cancer risk prediction models: Preliminary data analysis provided AUC values as follows: BCRAT+SNP = 0.656, IBIS+SNP= 0.628, BRCAPRO+SNP= 0.689, BOADICEA+SNP= 0.698.

The breast cancer risk prediction models examined place different weighting on the phenotypic components. For example, the IBIS model is weighted towards uncommon high-risk phenotypes, while the BCRAT is weighted towards lower risks in the general population. A combination of the 77 SNP score and the most appropriate model might substantially improve the ability to identify high-risk women in different screening populations.

Citation Format: Gillian Dite, Richard Allman, John L Hopper. Value of adding single-nucleotide polymorphism panel markers to phenotypic algorithms of breast cancer risk [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-09-05.
Abstract P6-09-07: The development of a prediction tool for moderate to severe diarrhea in HER-2/hormone positive metastatic breast cancer (MBC) patients receiving lapatinib in combination with letrozole (L-L)
Authors: Dranitsaris George , Locouture Mario E
Published: May 2015

Background: For patients with HER-2/hormone positive MBC, the addition of lapatinib to letrozole is associated improvements in tumour response rates and a prolongation of progression free survival. However, moderate to severe diarrhea (≥ grade 2) is a potentially serious toxicity which can lead to dose reductions, delays, hospitalizations and even the premature discontinuation of treatment. Patient care could substantially be improved if these diarrhea events could be accurately predicted through the use of validated and easy-to-use mathematical models. In this study, the development of a repeated measures model to predict the risk of ≥ grade 2 diarrhea prior to each month of L-L therapy is described.

Methods Data from 111 patients who received the L-L combination as part of a clinical trial were reviewed [Johnston, 2009]. Generalized estimating equations (GEE) were used to develop the final risk model using a backwards elimination process. Internal validation of the final regression coefficients was done using nonparametric bootstrapping. A risk scoring algorithm (range 0-250) was then derived from the final model coefficients. A receiver operating characteristic curve (ROC) analysis was then undertaken to measure the predictive accuracy of the final scoring algorithm.

Results: Presence of skin and lung metastases at baseline, cumulative lapatinib dose and Hg level (nadir) were identified as being important predictors for ≥ grade 2 diarrhea. There was also a negative association between time on therapy and risk of diarrhea where a higher frequency was observed in the first few months. The ROC analysis indicated good predictive accuracy with an area under the curve of 0.80 (95%CI: 0.72 – 0.88). Prior to each new month of therapy, patients with risk scores > 125 units would be considered at high risk for developing ≥ grade 2 diarrhea.

Conclusions: Risk of ≥ grade 2 diarrhea is associated with cumulative lapatinib exposure, disease related factors as well as Hg level. The planned external validation and eventual clinical application of this prediction tool will be an important source of risk information for the practicing oncologist and can enhance patient care by optimizing preventative therapies earlier in a proactive manner.

Citation Format: George Dranitsaris, Mario E Locouture. The development of a prediction tool for moderate to severe diarrhea in HER-2/hormone positive metastatic breast cancer (MBC) patients receiving lapatinib in combination with letrozole (L-L) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-09-07.
Abstract P6-10-12: Metformin increases survival in hormone receptor-positive, Her2-positive breast cancer patients with diabetes
Authors: Kim Hee Jeong , Kwon Hyun Wook , Lee Jong Won , Lee Sae Byul , Park Hee Seung , Ahn Sei Hyun , Shin Hae Na
Published: May 2015

Purpose

Metformin use has recently been observed to decrease both the rate and mortality of breast cancer. Our study was aim to determine whether metformin use is associated with survival in diabetic breast cancer patients by breast cancer subtype and systemic treatment

Patients and Methods

Data from the Asan Medical Center Breast Cancer Database from 1997 to 2007 were analyzed. The study cohort comprised 6,967 nondiabetic patients, 202 diabetic patients treated with metformin, and 184 diabetic patients that did not receive metformin. Patients who were divided into three groups by diabetes status and metformin use were also divided into four subgroups by hormone receptor and HER2-neu status.

Results

In Kaplan-Meier analysis, the metformin group had a significantly better overall and cancer specific survival outcome compared with non metformin diabetic group (P <0.005 for both). There was no difference in survival between the nondiabetic and metformin groups. In multivariate analysis, Compared with metformin group, patients who did not receive metformin tended to have a higher risk of metastasis with HR 5.37 (95%CI, 1.88 to 15.28) and breast cancer death with HR 6.51 (95% CI, 1.88 to 15.28) on the hormone receptor-positive and Her2-negative breast cancer. The significant survival benefit of metformin observed in diabetic patients who received chemotherapy and endocrine therapy (HR for DFS 2.14; 95% CI 1.14 to 4.04) was not seen in diabetic patients who did not receive these treatments.

Conclusion

Patients receiving metformin treatment when breast cancer diagnosis show a better prognosis only if they have hormone receptor-positive, HER2-positive tumors. Metformin treatment might provide a survival benefit when added to systemic therapy in diabetic patients.

Citation Format: Hee Jeong Kim, Hyun Wook Kwon, Jong Won Lee, Sae Byul Lee, Hee Seung Park, Sei Hyun Ahn, Hae Na Shin. Metformin increases survival in hormone receptor-positive, Her2-positive breast cancer patients with diabetes [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-10-12.
Abstract P6-10-19: Bone mineral density(BMD) monitoring in postmenopausal women with early stage estrogen and/or progesterone receptor positive breast cancer on aromastase inhibitor(AI) therapy at University of Toledo medical center. A quality improvement project
Authors: Taj Asma , Khuder Sadik , Mohamed Iman
Published: May 2015

Background

More than 70% of breast cancer patients develop endocrine-responsive disease with estrogen receptor (ER)-positive or progesterone receptor-positive tumors or both [1] and require endocrine treatment with either estrogen blockage or ablation. The aromatase inhibitors are highly effective well-tolerated treatment for postmenopausal endocrine-responsive breast cancer. However, their use is associated with accelerated bone loss and an increase in fracture risk(2, 3)

Method

Post menopausal patients with early stage breast cancer( stage I and stage II) which was ER and/or PR positive and who were on AI therapy were included. Total patients 243.Stage I (101) and stage II (142).Agents used were Anastrazole, letrozole, exemestane .BMD (bone mineral density monitoring)was done by DEXA(Dual-energy X-ray absorptiometry) scan, and compared with national guidelines.

Results

243 patients were included. At 0 years(at start of AI therapy) 150(62%) did not get a DEXA scan,40(16.4%) had normal DEXA scan, 48(19.8% )had osteopenia and 5( 2%) had osteoporosis. At 2 years from AI therapy 126(51.8%) did not get a DEXA scan, 35(14.4%) had normal DEXA scan, 73(30%) had osteopenia and 9(3.7%) had osteoporosis. At 5 years from AI therapy 180(74%) did not get a DEXA scan,21(8.6%) had normal DEXA scan, 35(14.4%) had osteopenia and 7(2.8%) had osteoporosis. Anastrazole and letrozole were equally associated with osteopenia/osteoporosis. Only 50% of patients with osteoporosis(10/21) received treatment for osteoporosis.

Conclusions

Although there is evidence of negative impact of the aromatase inhibitors on bone, our data still show a poor application of the recommendations in order to prevent osteoporosis related to the administration of these drugs. Part of the problem is the mixed literature on diagnosis and management of osteoporosis. Also medicare covers for a DEXA scan only once very two years.

The national compliance for managing AI induced bone loss is very low which points out tthat this is a global problem. Our suggestion is a more active implementation of the guidelines, also by means of a greater collaboration between the oncologist and the specialist in osteoporosis, and the offer of a diagnostic and therapeutic pathway.

Citation Format: Asma Taj, Sadik Khuder, Iman Mohamed. Bone mineral density(BMD) monitoring in postmenopausal women with early stage estrogen and/or progesterone receptor positive breast cancer on aromastase inhibitor(AI) therapy at University of Toledo medical center. A quality improvement project [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-10-19.
Abstract P6-12-05: Inducible suppression of insulin receptor substrate I inhibits IGF-I/insulin/estradiol dependent cell growth in MCF-7L breast cancer cells
Authors: Zhang Xihong , Varma Sidhant , Yee Douglas
Published: May 2015

Insulin receptor substrate (IRS) proteins are adaptor proteins downstream of insulin-like growth factor (IGF) and insulin receptors. IRS proteins play a role in cancer biology, with IRS1 function linked to mitogenesis and survival and IRS2 associated with metastasis. Moreover, this family of adaptor proteins is also involved in the signal transduction of many other transmembrane receptors. Therefore IRS proteins could be potential therapeutic targets for cancer therapy. To test the function of IRS-1, we created a doxycycline inducible IRS1 shRNA and stably transfected MCF-7L breast cancer cells. The level of IRS1 protein knockdown varied within different clones from 50 to 95% reduction compared to non-induced cells. IRS2 mRNA and protein levels were not significantly affected. We chose a high (3G5) and intermediate (3A7) IRS1 knockdown clones for further study. Doxycycline treated 3G5 and 3A7, showed partial inhibition of IGF-I, IGF-II and insulin stimulated phosphorylation of IRS1(Tyr1222) and AKT. pErk1,2 were slightly increased and pIGF-IR was unchanged compared to doxycycline non-treated cells. IRS-2 tyrosine phosphorylation was stimulated when IRS-1 was suppressed and may account for the persistent downstream cell signaling. Anti IGFIR antibody dalotuzumab (20µg/ml) effectively inhibited cell signaling stimulated by IGF-I, IGF-II and insulin in both doxycycline treated and non-treated cells. There was no obvious difference in cell signaling pattern between plus and minus doxycycline treated cells within 24 hour time course. In monolayer cell growth assays, IGF-I, IGF-II, insulin and estradiol growth stimulation were significantly inhibited when IRS-1 was suppressed in 3G5 cells. In 3A7 cells, which have a lower level of IRS-1 suppression, growth stimulation was moderately inhibited. In anchorage independent growth assays stimulated by IGF-I, colony number and size were inhibited by doxycycline-induced IRS-1 suppression with a reduction of 80% in 3G5 cells and 50% reduction in 3A7 cells. These results show that growth of MCF-7L cells are dependent on IRS-1 expression. Reduced IRS1 can hinder cancer cell growth and tumorigenicity even when signaling was not impaired potentially due to compensation by other adaptor proteins. We conclude that suppression of IRS-1 may inhibit several growth regulatory pathways in breast cancer and could serve as a potential drug target.

Citation Format: Xihong Zhang, Sidhant Varma, Douglas Yee. Inducible suppression of insulin receptor substrate I inhibits IGF-I/insulin/estradiol dependent cell growth in MCF-7L breast cancer cells [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-12-05.
Abstract P6-13-08: The DCIS Score - Potential for healthcare savings?
Authors: Young Rebekah , Gergelis Kimberly , Kalnicki Shalom , Fox Jana L
Published: May 2015

Introduction

The Oncotype Dx Recurrence Score for DCIS (DCIS Score) is a 12-gene assay derived from the original Oncotype DX test that evaluates recurrence risk among women with invasive carcinoma of the breast. The DCIS Score provides a local recurrence risk estimate at 10 years following lumpectomy for ductal carcinoma in situ (DCIS). Results can help guide decisions regarding adjuvant radiation (RT). Foregoing RT can be a source of significant healthcare savings. We investigated the actual healthcare dollar savings to-date in our patient population.

Methods

We evaluated patients in whom the DCIS Score was ordered (x) and calculated total cost of testing. Potential cost of RT was that of IMRT as reimbursed by Medicare for a hypofractionated (16 fraction) course, multiplied by x. Many of our large-breasted patients require IMRT to increase dose homogeneity and to limit dose to normal tissues. We also calculated potential cost with 3D conformal (3D-CRT). Total potential cost was the sum of testing and treatment costs, determined for each modality. The number of patients ultimately treated (y) was also multiplied by these costs. Total actual cost was the sum of test expenses and actual treatment costs. Savings was the difference between the total actual and total potential cost.

Results

From February, 2012 to May, 2014 the DCIS Score was performed in 38 patients (x= 38). Median age was 66 (40-85). Grade was low in 39%, intermediate in 45%, and high in 16%. 50% had necrosis present, and the median size of DCIS was 0.5cm (0.1 - 3.1cm). The total cost of testing was $4125 * 38 = $156,750. IMRT reimburses at approximately $23, 000 and 3D-CRT at approximately $11,000 per treatment. (Medicare reimbursement rates can vary among states.) The potential total cost of RT ranged from $418,000 - $874, 000; testing brought the total potential costs to $574, 750 - $1,030, 750. Upon receipt of the test results, 12 (y) patients ultimately underwent therapy. IMRT was given in 11 patients and 3D-CRT in 1, for a total treatment cost of $264, 000. Therefore, total actual expenditures were $420, 750. Savings amounted to (574, 750 – 420, 750) = $154, 000 to (1,030, 750– 420, 750) = $ 610, 000.

Conclusions

In the era of rising healthcare costs, it is imperative to examine instances of possible over-treatment. The DCIS Score has the potential to save not only healthcare dollars, but to spare patients radiation side effects, time lost from work, and transportation expenses. While there are costs associated with the assay, if ordered judiciously, these can be offset by the subsequent savings from eliminating treatment.

Citation Format: Rebekah Young, Kimberly Gergelis, Shalom Kalnicki, Jana L Fox. The DCIS Score - Potential for healthcare savings? [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-13-08.
Abstract P6-17-02: Inhibition of osteolytic tumor growth by 5-FdU-alendronate, a bisphosphonate conjugate that maintains bone formation: Implications for treatment of osteolytic bone lesions
Authors: Schem Christian , Tower Rob J , Kneissl Philipp , Rambow Anna C , Campbell Graeme M , Heilmann Thorsten , Trauzold Anna , Jonat Walter , Glüer Claus C , Schott Sarah , Tiwari Sanjay
Published: May 2015

Patients with breast cancer bone metastases suffer significant morbity from skeletal-related events but an effective agent that inhibits bone resorption while maintaining bone formation has not been identified. In this study we tested the therapeutic efficacy of a novel drug, 5-FdU-ale, a conjugate between the anti-metabolite 5-FdU and the bisphosphonate alendronate, in a mouse model of breast cancer bone metastases. Administration of 5-FdU-ale in vitro induces cell cycle arrest similar to treatment with unconjugated 5-FdU. In vivo, mice harboring bone lesions treated with 5-FdU-ale showed a reduction in tumor size not observed with administration of either Alendronate or 5-FdU. Since osteolysis mediated release of growth factors from bone contribute to tumor growth, we show 5-FdU-ale treatment significantly reduces bone resorption, although uniquely, the inhibition of osteoclast activity is not mediated through inhibition of prenylation of small GTPases. Furthermore, and in contrast to Alendronate, there is no concomitant decrease in bone formation activity, as determined by serum osteocaclin levels. This finding is supported by micro-CT analyses which reveal significantly higher bone volume and histologically, pockets of tumor cells are observed largely confined to regions of marrow space between endochondral and trabecular bone. Taken together, we conclude that 5-FdU-ale has potent anti-tumor efficacy in osteolytic bone lesions mediated uniquely through bone formation activity of osteoblasts and inhibition of bone resorption. The study identifies the important role of osteoblast in not only preventing the osteolytic metastatic phenotype but as a means of harnessing the therapeutic potential of bone formation to treat osteolytic lesions.

Citation Format: Christian Schem, Rob J Tower, Philipp Kneissl, Anna C Rambow, Graeme M Campbell, Thorsten Heilmann, Anna Trauzold, Walter Jonat, Claus C Glüer, Sarah Schott, Sanjay Tiwari. Inhibition of osteolytic tumor growth by 5-FdU-alendronate, a bisphosphonate conjugate that maintains bone formation: Implications for treatment of osteolytic bone lesions [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-17-02.
Abstract PL-2: Patient Derived Xenografts - Pre-Clinical Models for Prevention and Treatment of Metastasis
Authors: Welm Alana L.
Published: May 2015

Twenty to thirty percent of breast cancer patients eventually develop metastasis despite receiving state-of-the-art therapies. Clearly, identifying better ways to eliminate micro-metastatic tumor cells is paramount to eradicating death from breast cancer. Unfortunately, history suggests that developing yet another drug to target yet another pathway involved in tumor progression will not cure breast cancer. We now know that every tumor is unique; each tumor is heterogenous; tumors hijack multiple, redundant pathways to survive and grow; dormant tumor cells are resistant to chemotherapy; and tumors evolve resistance under pressure of therapy.

To better understand the problem of metastasis, and to develop better treatments, we must utilize in vivo models of metastasis that best recapitulate heterogenous human breast cancers. We have generated a collection of orthotopic patient-derived breast tumor xenograft (PDX) models from all of the major breast cancer subtypes. We found remarkable fidelity between PDX models and bona fide breast tumors, including the ability to metastasize and to evolve under pressure of treatment. This presentation will highlight the strengths and pitfalls of PDX models of breast cancer and how they might be utilized to develop new strategies for treatment.

Citation Format: Alana L. Welm. Patient Derived Xenografts - Pre-Clinical Models for Prevention and Treatment of Metastasis [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PL-2.
Abstract S5-01: The Connecticut experiment: 4 years of screening women with dense breasts with bilateral ultrasound
Authors: Weigert Jean M
Published: May 2015

OBJECTIVE: To determine if the addition of screening breast ultrasound in women with mammographically normal but dense breasts has increased breast cancer detection over the 4 years since the legislation was first enacted in 2009.

METHODS: The study utilized a retrospective chart review. Data collected included: (1) total number of screening mammograms; (2) total number of dense breast screening ultrasounds; (3) screening ultrasound Breast Imaging Reporting Data System (BI-RADS) code results; (4) biopsy results; and (5) demographic data on women with malignant biopsies. Data was obtained from included sites from October 2009 through December 2013.

FINDINGS: Data was collected from 2 Radiology practices with a total of 5 sites.

In year 1, 30670 mammograms and 2706 screening ultrasounds were performed. In year 2, 32050 mammograms and 3351 ultrasounds; in year 3, 32230 mammograms and 4128 ultrasounds and in year 4, 27937 mammograms and 3331 ultrasounds were performed.

In year 1, 151 ultrasounds were BIRADS 4 or 5 with 11 cancers detected. The PPV was 7.1%; the detection rate was 4/1000 and 22% of eligible women had the study (assuming 40% of women have dense breasts). In year 2, 180 ultrasounds were BIRADs 4 and 5 with 11 cancers detected. The PPV was 6.1% and the cancer detection rate was 3.2/1000 with 26% of eligible women having the study. In year 3 148 ultrasounds were BIRAD 4 and 5 with 13 cancers detected. The PPV was 8.1% and the cancer detection rate was 3.2/1000 with 32% of eligible women having the study. In year 4, 53 ultrasounds were BIRAD 4 and 5 with 11 cancers. The PPV was 17.2% with the cancer detection rate of 3.3/1000 and 28% of eligible women having the study.

Four Years of Screening Breast Ultrasound Data Year 1Year 2Year 3Year 4Screening Mammograms30670320503223027937Breast Ultrasounds for Dense Breasts2706335141283331BIRAD 4 and 5 Ultrasounds15118017853Cancers11111311PPV7.16.18.117.2Number Cancers per 1000 Screened4.03.23.23.3% Eligible Screened22.126.132.028.3

CONCLUSIONS: Based on the data collected from these sites, screening breast ultrasound in women with dense breast parenchyma detects mammographically occult malignancy. Over the 4 years studied, the PPV improved from 7% to 17.2% indicating that the selection of lesions biopsied was more accurate with fewer false positives. The rate of detection in the first year was 4.0/1000 and then remained stable at 3.2/1000 in the three subsequent years. Of concern, the number of eligible women who elect to have the additional test remains low at about 30% which is due to several factors including education and cost.

Citation Format: Jean M Weigert. The Connecticut experiment: 4 years of screening women with dense breasts with bilateral ultrasound [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S5-01.
Abstract A059: Context-dependent regulation of breast cancer metastasis by E-cadherin and p120-catenin
Authors: Schackmann Ron CJ , Klarenbeek Sjoerd , Amersfoort Miranda van , Jonkers Jos , Diest Paul van , Derksen Patrick
Published: May 2015

While it is well established that mutational inactivation of E-cadherin is a causal event in the development and progression of invasive breast cancer, still little is known about how this event controls the metastatic process.

Using conditional E-cadherin knockout mouse models of human invasive lobular carcinoma (ILC), we recently demonstrated that p120-catenin (p120) translocates to the cytosol upon E-cadherin inactivation. Here, it acts as an oncogene by regulating Rock-dependent control of tumor growth and metastasis through binding and inhibition of the Rho antagonist Mrip. Furthermore, new evidence indicates that p120 shuttles to the nucleus where it relieves Kaiso-dependent transcriptional repression of Wnt11, leading to autocrine activation of RhoA.

Conversely, since p120 controls E-cadherin stability and turnover, we also addressed the hypothesis that p120 may function as a tumor suppressor in breast cancer. In contrast to E-cadherin loss and the development of metastatic ILC, we show that somatic inactivation of p120 results in the formation of stromal-dense tumors resembling human metaplastic carcinoma that metastasize to lungs and lymph nodes. Mechanistically, we demonstrate that acquisition of metastatic potential was acquired through relieve of E-cadherin-dependent repression of growth factor receptor (GFR) function, leading to hyper-activation of GFR signaling and subsequent anchorage independence.

In summary, our data show that p120 can act as an oncogene or metastasis suppressor, depending on context and timing of junctional inactivation. Furthermore, our experiments indicate that targeted intervention strategies using Rock inhibitors may be applicable for the treatment of ILC. Based on our findings we also anticipate that patients suffering from E-cadherin or p120 negative breast cancer will benefit from clinically established inhibitors targeting GFR/PI3K/AKT/FOXO pathways in the absence of GFR or PIK3CA activating mutations.

Citation Format: Ron CJ Schackmann, Sjoerd Klarenbeek, Miranda van Amersfoort, Jos Jonkers, Paul van Diest, Patrick Derksen. Context-dependent regulation of breast cancer metastasis by E-cadherin and p120-catenin. [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 A059.
Abstract A062: Sensitizing low BIM expressing breast cancers to targeted therapies
Authors: Faber Anthony C. , Vora Sadhna , Engelman Jeffrey A.
Published: May 2015

HER2 amplification is found in up to 20% of breast cancers and PIK3CA mutations occur in up to 30%. These cancers are susceptible to targeted therapies directed against oncogenic HER2 and PI3K. Emerging evidence from clinical trials has revealed a surprising heterogeneity in response to targeted therapies, for example within HER2 positive breast cancer patients, the efficacy of HER2 inhibitors has varied. We have previously shown in breast cancer cell lines and a small cohort of HER2 positive breast cancer patients that low levels of the pro-apoptotic BIM can confer intrinsic resistance to HER2 inhibitors, by repressing the apoptotic response following treatment. Here in, we investigated the ability of a BCL-2/Bcl-XL inhibitor to enhance the apoptotic response specifically in low BIM HER2 amplified and PIK3CA mutant breast cancers with intrinsic resistance to targeted therapies, by freeing up BIM from BCL-2:BIM and BCL-xL:BIM complexes. We found that in these cancers, the addition of BCL-2/BCL-xL inhibitors synergized with HER2 inhibitors and PI3K inhibitors to induce apoptosis, and to similar levels induced by targeted therapy alone in the high BIM expressing breast cancers. Biochemical analysis revealed that PI3K inhibition downregulated MCL-1 in PIK3CA mutants, which leads to a further increase in the amount of free BIM, further “maximizing” the otherwise low levels of cellular BIM in these cells. These results translated to tumor regressions in mouse xenografts treated with the combination, similar to what was seen with single-agent PI3K inhibitor in a high BIM expressing PIK3CA mutant breast cancer xenograft model. Thus, combining a BCL-2/BCL-xL inhibitor with the appropriate targeted therapy may overcome intrinsic resistance caused by low BIM expression in HER2 amplified and PIK3CA mutant breast cancer.

Citation Format: Anthony C. Faber, Sadhna Vora, Jeffrey A. Engelman. Sensitizing low BIM expressing breast cancers to targeted therapies. [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 A062.
Abstract A067: Targeting p21-activated kinases in breast cancer
Authors: Hoeflich Klaus , Ong Christy , Lyle Karen , Jubb Adrian , Zhou Wei , Harris Adrian , Belvin Marcia , Friedman Lori , Koeppen Hartmut , Rudolph Joachim , Staben Steven
Published: May 2015

Luminal breast cancer is the most commonly diagnosed cancer worldwide and mechanisms of innate and acquired resistance are not yet well understood. P21-activated kinases (PAKs) are members of the STE20 family of serine/threonine kinases that lie downstream of receptor tyrosine kinases and Rho family GTPases. PAKs regulate many cellular processes that are commonly perturbed in cancer, including migration, polarization and proliferation, and are therapeutic targets of interest. PAK1 is also overexpressed in several cancers and we recently showed that focal genomic amplification of PAK1 occurs in ~8% of luminal breast cancer (Proc Natl Acad Sci 2011; 108:7177). PAK1 amplification has also been associated with poor patient outcome and PAK1 is a putative mediator of resistance to anti-estrogen therapy (Nature 2012; 486:346). The aim of this study was to further characterize PAK family kinases in breast adenocarcinoma. Luminal breast cancer cells with PAK1 focal amplification rapidly underwent apoptosis following inhibition of this kinase. To identify potential mechanisms of acquired resistance we have derived PAK1-resistant cell lines and begun characterizing via genomic and proteomics approaches. Furthermore, in contrast to the role of PAK1 in luminal breast cancer, elevated expression of PAK4 was associated with poor outcome in basal-like breast cancer. We developed a novel small molecule inhibitor with high potency and selectivity of group II PAKs to delineate the role of PAK4 signaling in basal breast cancer. Together, our results provide evidence for dysregulation of PAK1 and PAK4 in differing subtypes of breast cancer and roles in for these kinases in cellular survival, proliferation and migration in this tumor indication.

Citation Format: Klaus Hoeflich, Christy Ong, Karen Lyle, Adrian Jubb, Wei Zhou, Adrian Harris, Marcia Belvin, Lori Friedman, Hartmut Koeppen, Joachim Rudolph, Steven Staben. Targeting p21-activated kinases 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 A067.