Abstract P3-07-10: The role of CBP/FOXM1 in triple negative breast cancer

Background: Accurate assessment of prognostic and predictive biomarkers (estrogen receptor, progesterone receptor, HER2) plays a critical role in the clinical management of breast cancer. Triple negative breast cancers (TNBCs) lack the expression of all three targets, and no targetable molecular pathways have been identified to date. Hence, TNBCs are treated with non-targeted, cytotoxic chemotherapeutic agents (e.g. paclitaxel), and are characterized by high rates of drug resistance and metastatic relapse. CREB binding protein (CBP) has been implicated in cell growth and malignant transformation in various cancers. CBP is an important co-activator in the β-catenin driven transcription, including the Wnt signaling pathway, which has been implicated in TNBC biology. The Kahn lab has developed a specific CBP-binding small molecule inhibitor, ICG-001. We hypothesized that CBP-signaling plays an important role in TNBC biology and may provide a novel therapeutic target.

Methods: We used TOP-flash assay to quantify Wnt signaling activity in TNBC. ICG-001 treatment combined with RNA Seq was used to characterize the role of CBP in TNBC cell line models. Co-immunoprecipitation (CoIP), protein and gene expression studies, as well as gene knock-down were used for validation. In vitro drug resistant cell line models as well as in vivo cell line (n=40 mice) and patient derived xenografts (PDX) in NOD scid gamma mouse models (2 patients, n=40 mice per patient) (treatmenent groups: control, paclitaxel, ICG-001, paclitaxel+ICG-001, n=5 mice per condition, primary and secondary implantation) were used to establish the effect of CBP inhibition via ICG-001 in TNBC on drug resistance and metastasis. We used the TCGA breast cancer data set to substantiate the experimental results.

Results: We demonstrated that gene expression in TNBC is CBP, but not Wnt signaling dependent, and can be disrupted via ICG-001. RNA Seq analysis of TNBC cells treated with ICG-001 revealed Forkhead box M1 (FOXM1) as a potential downstream regulator. CoIP demonstrated that CBP binding to the FOXM1/β-catenin transcriptional complex. Treatment with ICG-001 revealed that CBP/FOXM1 binding, but not FOXM1/ β-catenin binding, is critical for FOXM1 expression. The PDX mouse models demonstrated that FOXM1 expression correlates with response to chemotherapy and disease recurrence in vivo. Treatment with ICG-001 sensitized FOXM1 high tumors to chemotherapeutic treatment and statistically significantly reduced tumor growth in serial transplantation experiments. Comparison of clinical data with FOXM1 expression in tumor samples from patients indicated that high levels of FOXM1 were associated with disease relapse and poor survival outcomes.

Conclusion: CBP/FOXM1 binding is critical for FOXM1 expression. Targeting CBP/FOXM1 binding via ICG-001 could provide a novel therapeutic strategy in TNBC. The use of clinically annotated tissue microarrays containing a total of 430 breast tissue cores (51 TNBC cases) is currently pending to correlate nuclear protein expression of CBP and FOXM1 with survival outcomes in TNBC. FOXM1 and CBP could potentially be of value as predictive biomarkers in TNBC. These results could provide a clinical-translational rational for patient stratification based on CBP and FOXM1 expression for clinical trials exploring the therapeutic potential of FOXM1 inhibition via ICG-001 in combination with chemotherapy.

Citation Format: Ring A, Nguyen C, Lenz H-J, Tripathy D, Lang JE, Kahn M. The role of CBP/FOXM1 in triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-10.

Abstract OT3-02-05: NCI-2016-00367: A phase IIB study of neoadjuvant ZT regimen (enzalutamide therapy in combination with weekly paclitaxel) for androgen receptor (AR)-positive triple-negative breast cancer (TNBC)

BACKGROUND: Approximately 50% of TNBC expresses AR by immunohistochemical (IHC) staining. Luminal androgen receptor (LAR) subtype is heavily enriched in hormonally regulated genes, yet negative for ER by IHC. LAR is associated with low pCR rates and long survival. Preclinical data have shown that taxanes inhibit translocation of AR from the cytoplasm to the nucleus where AR is activated. Combining paclitaxel with enzalutamide may inhibit the AR pathway synergistically thereby increasing pCR rates. We hypothesized that patients with AR-positive TNBC who have chemo-insensitive disease (CID) after initial anthracycline-based chemotherapy treated with ZT would have higher RCB-0 and RCB-I rates than those who receive conventional taxane-based chemotherapy. Our team developed a clinical trial to identify patients with CID (ARTEMIS: A Randomized, TNBC Enrolling trial to confirm Molecular profiling Improves Survival). In the ARTEMIS trial, treatment-naïve patients with localized TNBC undergo a pretreatment biopsy and then begin anthracycline-based chemotherapy. Molecular testing results and radiographic response assessment are used to identify CID and will guide the second phase of neoadjuvant chemotherapy (NACT) to overcome CID.

PRIMARY OBJECTIVE: To determine RCB-0 and RCB-I rates of patients with TNBC who have CID to initial anthracycline-based chemotherapy and who received ZT.

TRIAL DESIGN AND STATISTICAL METHODS: Patients with CID from the ARTEMIS trial can enroll in the 12-week ZT (paclitaxel, 80 mg/m2 intravenously per week; enzalutamide, 160 mg orally per day). We will define pCR (RCB-0) or RCB-I as a response, using a Simon optimal 2-stage design with alpha=beta=10% and then setting the threshold for an acceptable pCR or RCB-I rate at 20%. We will enroll 12 patients into the first stage. If no patients experience pCR or RCB-I, we will stop the study after the first stage. If at least 1 patient experiences pCR or RCB-I, we will enroll 25 more patients for a total of 37 patients. We would declare the treatment worthy of further study if at least 4 of the 37 patients experience pCR or RCB-I. This design has a 54% probability of early termination after the first stage if the true pCR or RCB-I probability is 5%. Because patients with CID have a very low chance (5%) of achieving pCR with additional chemotherapy, improving pCR rates to 20% in this patient population would be clinically meaningful.

BRIEF ELIGIBILITY CRITERIA: Inclusion criteria: Primary invasive TNBC patients who have CID under the ARTEMIS trial; AR+ ≥1% nuclear staining by IHC; and adequate physical, organ, bone marrow, and cardiac functions. Exclusion criteria: Pregnant or lactating patients, history of colitis or absorption abnormality, known or suspected brain metastasis or leptomeningeal disease, or history of seizure.

CORRELATIVE SCIENCE: Enumeration of circulating tumor cells (CTCs) and expression of CTC-related gene transcripts will be measured to correlate CTC characteristics and/or gene profiles related to the AR pathway and treatment response to ZT.

Citation Format: Fujii T, Lim B, Helgason T, Hess KR, Gilcrease MZ, Willey JS, Tripathy D, Litton JK, Moulder S, Krishnamurthy S, Yang W, Reuben JM, Symmans WF, Ueno NT. NCI-2016-00367: A phase IIB study of neoadjuvant ZT regimen (enzalutamide therapy in combination with weekly paclitaxel) for androgen receptor (AR)-positive triple-negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT3-02-05.

Abstract P5-11-18: Trajectory of patient (Pt) reported physical function (PF) during and after neoadjuvant chemotherapy in the I-SPY 2 trial

Background

Patients (pts) receiving chemotherapy for breast cancer experience toxicities impacting short and long-term quality of life (QOL). Within I-SPY 2, a trial adaptively randomizing stage II/III breast cancer pts to neoadjuvant chemotherapy +/- an investigational agent, we are collecting pt reported outcome (PRO) data to understand the impact of investigational agents on QOL. This PRO sub-study provides a unique opportunity to study QOL longitudinally and explore how pt and tumor characteristics, exposure to investigational therapies, and surgical outcome impact QOL.

Methods

Pts enrolled in this trial receive paclitaxel (T) +/- an investigational agent for 12 weeks followed by 4 cycles of doxorubicin and cyclophosphamide (AC). Surveys include the EORTC QLQ-C30 and BR-23, and PROMIS measures for QOL metrics including but not limited to physical function (PF), anxiety, and depression. Surveys are administered pre-chemotherapy to 2 years post-surgery. PF data from the EORTC and PROMIS instruments was analyzed for 238 pts at 5 sites (UCSF, UCSD, U of Pennsylvania, U of Minnesota, and Swedish Cancer Center). 48 pts completed baseline, inter-regimen (between T and AC), pre-operative and post-surgery surveys. Of the 48 pts 32 completed a 6-month follow up (FUP) and 31 completed a 1-year FUP survey. A linear mixed effect model, adjusting for HER2 status and treatment type was used to evaluate changes in PF over time. Sample size is small and statistics are descriptive rather than inferential.

Results

Median age of pts in this analysis was 50 (range 27-72).

Table 1 shows PROMIS & EORTC PF scores in this cohort.Time Point  PROMISEORTC  nMeanSEMeanSEPre-TreatmentAll4852.51.092.02.0 HER2+1553.51.594.12.2 HER2-3352.11.391.12.8Inter-RegimenAll4845.51.282.22.7 HER2+1548.62.384.44.2 HER2-3344.11.381.23.4Pre-SurgeryAll4843.91.179.42.3 HER2+1545.12.275.34.1 HER2-3343.41.381.32.86-Month FUPAll3248.11.487.41.9 HER2+1247.52.285.03.3 HER2-2048.41.888.92.41 Year FUPAll3148.91.488.43.1 HER2+949.12.988.95.4 HER2-2248.81.788.33.8

At baseline, mean PROMIS PF scores were higher than the US average (mean = 50) but declined as expected throughout treatment. HER2+ patients experienced a similar degree of recovery as HER2- pts post-surgery despite adjuvant treatment with Herceptin. Analysis of post-operative PROMIS PF indicated an average score within the U.S. general population (mean =50) but did not return to higher functioning seen at baseline levels (mean 52.5, p-value < 0.05). Analysis of the EORTC PF sub-scale demonstrated a similar trend; however, the baseline and post-operative difference was not significant (p-value=0.15 for both FUP). Finding supports PROMIS PF ability to measure high functioning cancer patients.

Conclusions: Among a subset of pts who completed all surveys in the I-SPY 2 QOL substudy, PF did not return to baseline at 6-12 months post-operatively. Through transition to an electronic platform of data collection we hope to improve compliance with survey completion. We continue to analyze other QOL measures and plan to correlate QOL data with treatment arm, adverse events, comorbidities, and response to neoadjuvant treatment.

Citation Format: Shah M, Jensen R, Yau C, Straehley I, Berry DA, DeMichele A, Buxton MB, Hylton NM, Perlmutter J, Symmans WF, Tripathy D, Yee D, Wallace A, Kaplan HG, Clark A, Chien AJ, I-SPY 2 Investigators, Esserman LJ, Melisko ME. Trajectory of patient (Pt) reported physical function (PF) during and after neoadjuvant chemotherapy in the I-SPY 2 trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-11-18.

c-Jun N-terminal kinase promotes stem cell phenotype in triple-negative breast cancer through upregulation of Notch1 via activation of c-Jun

c-Jun N-terminal kinase (JNK) plays a vital role in malignant transformation of different cancers, and JNK is highly activated in basal-like triple-negative breast cancer (TNBC). However, the roles of JNK in regulating cancer stem-like cell (CSC) phenotype and tumorigenesis in TNBC are not well defined. JNK is known to mediate many cellular events via activating c-Jun. Here, we found that JNK regulated c-Jun activation in TNBC cells and that JNK activation correlated with c-Jun activation in TNBC tumors. Furthermore, the expression level of c-Jun was significantly higher in TNBC tumors than in non-TNBC tumors, and high c-Jun mRNA level was associated with shorter disease-free survival of patients with TNBC. Thus, we hypothesized that the JNK/c-Jun signaling pathway contributes to TNBC tumorigenesis. We found that knockdown of JNK1 or JNK2 or treatment with JNK-IN-8, an adenosine triphosphate-competitive irreversible pan-JNK inhibitor, significantly reduced cell proliferation, the ALDH1⁺ and CD44⁺/CD24^- CSC subpopulations, and mammosphere formation, indicating that JNK promotes CSC self-renewal and maintenance in TNBC. We further demonstrated that both JNK1 and JNK2 regulated Notch1 transcription via activation of c-Jun and that the JNK/c-Jun signaling pathway promoted CSC phenotype through Notch1 signaling in TNBC. In a TNBC xenograft mouse model, JNK-IN-8 significantly suppressed tumor growth in a dose-dependent manner by inhibiting acquisition of the CSC phenotype. Taken together, our data demonstrate that JNK regulates TNBC tumorigenesis by promoting CSC phenotype through Notch1 signaling via activation of c-Jun and indicate that JNK/c-Jun/Notch1 signaling is a potential therapeutic target for TNBC.

Abstract P1-14-07: Association between quantitative values of estrogen receptor expression level and pathological complete response in human epidermal growth factor 2-negative breast cancer: Should the clinical definition of triple-negative breast cancer be redefined?

Background: The American Society of Clinical Oncology/College of American Pathologists recommended that the cut-off for negative status of estrogen receptor (ER) should be <1% positively staining cells, although a 10% cut-off has often been used clinically. Prior studies reported that patients with ER ranging from 1% to 9% showed survival outcomes and molecular features similar to those of patients with ER positivity of <1%; however, those studies did not take into account patients' human epidermal growth factor 2 (HER2) status. This means we have yet to clarify the exact clinical definition of triple-negative breast cancer (TNBC) on the basis of response to preoperative chemotherapy. Previous studies reported that hormone receptor–positive tumors were less sensitive to systemic chemotherapies. On the basis of these facts, we hypothesized that in patients with HER2-negative breast cancer ER expression level as a continuous variable has an inverse linear association with pathological complete response (pCR) rate. Our primary objective was to determine whether a quantitative value of ER between 0% and 10% is predictive of pCR rate in HER2-negative patients treated with neoadjuvant chemotherapy. Secondary objective was to find the ideal cut-off value of ER expression.

Methods: We included newly diagnosed stage I-III HER2-negative breast cancer patients with available ER (0%≤ER<10%) who were treated with neoadjuvant systemic chemotherapy. ER status was determined by immunohistochemical (IHC) staining; HER2 status was determined by IHC and/or FISH. We used univariate and multivariate logistic regression models to determine the association between baseline variables and pCR. A backward stepwise method was used to select the covariates for the multivariate analysis. Recursive partitioning and regression tree method were used to identify the potential significant cut-off of ER.

Results: The analysis included 1155 patients with newly diagnosed HER2-negative invasive breast cancer. The univariate logistic regression analysis showed that ER as a continuous variable was not a statistically significant factor for predicting pCR (ER: OR=0.98, 95%CI: 0.9-1.07, P=0.68). In the multivariate analysis, ER status again was not a significant factor for predicting pCR (OR=0.97, 95%CI 0.9-1.06, P=0.55). ER as a categorical variable, there was no significant difference of the pCR rate between 0<ER<1 and 1≤ER<10 groups (OR=1.27, 95%CI: 0.62-2.62, P=0.52). Among ER> 0 (n=229), the recommended cut-off value of ER was 5.5. However, the odds ratio of pCR rate divided by this value of 5.5 was not significant (ER≤5 vs ER>5; OR 1.94 95%CI 0.54-6.95 P=0.31).

Conclusion: Evaluating ER (<10%) as a continuous variable showed no association with pCR rate, and no cut-off of ER was identified with which to stratify patients into groups more or less likely to achieve pCR. A potential meaningful cut-off ER value might exist between 10% and 100% in HER2-negative patients. We will explore whether a meaningful cut-off ER value exists that will change the pCR rate and possibly lead to redefining the clinical definition of TNBC.

Citation Format: Fujii T, Kogawa T, Dong W, Moulder S, Litton JK, Tripathy D, Lim B, Shen Y, Ueno NT. Association between quantitative values of estrogen receptor expression level and pathological complete response in human epidermal growth factor 2-negative breast cancer: Should the clinical definition of triple-negative breast cancer be redefined?. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-14-07.

Abstract P3-07-58: CD44v as a potential predictive biomarker for pathologic complete response in primary HER2+ breast cancer: Utility of adaptive response biopsy in preoperative therapy

Background: Preoperative dual anti-HER2 therapy with lapatinib and trastuzumab in combination with conventional chemotherapy demonstrates a higher pathologic complete response rate (pCR) than trastuzumab with chemotherapy in patients with HER2+ breast cancer. Preoperative chemotherapy has been reported to increase the fraction of cancer stem-like cells (CSCs) in breast cancer, but this effect has not been well validated in clinical setting. Cancer cells with the epithelial-mesenchymal transition (EMT) phenotype also exhibit stem cell–like properties with drug resistance. Our goal was to determine the quantitative values of various biomarkers in baseline and adaptive response biopsy specimens and in subsequent surgical specimens to predict pCR in patients treated with dual anti-HER2 therapy as demonstrated by reduction of CSCs, phosphorylated receptors and signaling kinases, and circulating tumor cells (CTC) with the EMT phenotype. Methods: Eighteen patients with operable primary HER2+ invasive breast cancer (≥T2 excluding inflammatory breast cancer, any N) were eligible. Patients received lapatinib (1000 mg PO daily) + trastuzumab (4 mg/kg at loading, then 2 mg/kg IV weekly) for the first 6 weeks, then lapatinib (750 mg daily) + trastuzumab (2 mg/kg IV weekly) + paclitaxel (80 mg/m2 IV weekly) for 12 weeks, followed by surgery (ClinicalTrials.gov Identifier: NCT01688609). Tumor and blood specimens were collected before (baseline), after the 6 weeks of dual anti-HER2 therapy (adaptive response biopsy), and at 18 weeks, after 12 weeks of dual anti-HER2 therapy + paclitaxel (surgical specimens). We measured CSC biomarkers CD44 variant (CD44v) and aldehyde dehydrogenase-1 in tumor tissues, EMT markers in CTCs (TWIST1, SNAIL1, SLUG, ZEB1, and FOXC2) in blood samples by quantitative RT-PCR, and the ratios of phosphorylated EGFR (pEGFR)/EGFR, pHER2/HER2, pERK/ERK, and pAkt/Akt in tumor tissues. All tissue and CTC biomarker levels at all three time points were evaluated for their association with response via Fisher's exact test, McNemar's test, and Wilcoxon rank sum test according to the variables. Results: Eight of 18 patients (44.4%) achieved pCR after dual anti-HER2 therapy + concurrent paclitaxel. All patients who achieved pCR showed reduction or disappearance of CD44v+ cells over the treatment course. Five of the 10 non-pCR patients showed consistent CD44v expression or enrichment after dual anti-HER2 therapy in both the adaptive response biopsy and the surgical specimens. None of the eight pCR patients had detectable CD44v in the 7-week adaptive response biopsy specimen (Fisher exact test, two-tailed, P = 0.0359). None of the other markers significantly predicted pCR. Conclusion: Persistent expression or enrichment of CD44v was suggested to be predictive for non-pCR in breast cancer patients treated with preoperative dual anti-HER2 therapy plus concurrent cytotoxic chemotherapy. A single evaluation of biomarkers before therapy is insufficient for prediction of clinical response. Application of the adaptive response biopsy during the course of preoperative therapy might play a significant role in the success of therapeutic strategies that target CSCs.

Citation Format: Yamauchi T, Imamura CK, Yamauchi H, Jinno H, Takahashi M, Kitagawa Y, Nakamura S, Lim B, Krishnamurthy S, Reuben JM, Liu D, Tripathy D, Zujewski JA, Chen H, Takebe N, Saya H, Ueno NT. CD44v as a potential predictive biomarker for pathologic complete response in primary HER2+ breast cancer: Utility of adaptive response biopsy in preoperative therapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-58.

Abstract OT2-03-03: Women's triple-negative, first-line treatment: Improving outcomes in triple-negative breast cancer using molecular triaging and diagnostic imaging to guide neoadjuvant therapy

BACKGROUND:

In triple negative breast cancer (TNBC), pathologic compete response/residual cancer burden-0 (pCR/RCB-0) or minimal residual disease (RCB-I) following neoadjuvant chemotherapy (NACT) is associated with a good prognosis. This is in contrast to extensive residual disease (RCB-II-III) which carries approximately a 50% chance of recurrence. These patients have a particularly poor prognosis as there are currently no targeted agents to salvage chemoresistant disease. It is important to predict pCR in order to direct responsive disease toward standard NACT and non-responsive disease (NRD) to therapy on clinical trials.

TRIAL DESIGN:

The use of genomic signatures (JAMA, 2011; 305:1873-81) and imaging to predict response to NACT will be validated, and the clinical impact of selecting patients with predicted NRD for targeted therapy on clinical trial will be determined. Patients will undergo primary tumor biopsy for molecular profiling and will be randomized 2:1 to know the results versus not (control). Following that, all patients will receive 4 cycles of anthracycline-based NACT, with imaging used for response assessment. Patients with molecular/imaging criteria for NRD will be offered enrollment on a clinical trial based upon molecular profiling or based upon physician/patient choice (control).

INCLUSION CRITERIA:

Tumor size ≥1.5 cm diameter; TNBC by standard assays; ≥18 years of age; LVEF ≥50%; adequate organ and bone marrow function

EXCLUSION CRITERIA:

Stage IV disease; invasive cancer within 5 years; excisional biopsy of the primary tumor; features that limit response assessment by imaging; unfit for taxane and/or antracycline regimens; prior anthracycline therapy; ≥grade II neuropathy; Zubrod performance status of ≥2; history of serious cardiac events

PRIMARY AIM:

- Prospectively determine the impact of a molecular diagnostic/imaging platform in patients with localized invasive TNBC

SECONDARY AIMS:

- Compare rates of clinical trial enrollment

- Evaluate disease free survival in the experimental arms compared to control standard NACT

- Perform integrated biomarker analyses and identify therapeutic targets for resistant disease

STATISTICAL METHODS:

A maximum of 360 patients will be randomized (2:1)using a group sequential design with one-sided O'Brien-Fleming boundaries, with two equally spaced binding interim tests for futility and superiority and one final test, having an overall Type I error .05 and power .80 to detect an improvement in pCR/RCB-I from 50% to 64%.

Citation Format: Mitri ZI, Ueno NT, Yang W, Valero V, Litton JK, Murthy RK, Ibrahim NK, Arun BK, Mittendorf EA, Hunt KK, Meric-Bernstam F, Thompson A, Piwnica-Worms H, Tripathy D, Symmans F, Moulder-Thompson S. Women's triple-negative, first-line treatment: Improving outcomes in triple-negative breast cancer using molecular triaging and diagnostic imaging to guide neoadjuvant therapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT2-03-03.

Abstract S3-02: Molecular predictors of outcome on adjuvant CAF plus tamoxifen (T) vs T in postmenopausal patients (pts) with ER+, node+ breast cancer – Transcriptome expression analysis of the phase III trial SWOG-8814

BACKGROUND: In SWOG-8814A, pts with ER+ node+ breast cancer and low 21 gene recurrence scores (RS) had good prognosis and no CAF benefit, but high RS predicted longer survival from CAF followed by T (CAF-T) vs T (Albain, Lancet Oncol 2010). The aims of SWOG-8814B were to identify novel genes and networks for 1) prognosis of early and late relapse and 2) prediction of CAF benefit, using whole transcriptome expression analysis with next generation RNA sequencing (NGS).

METHODS: Stored RNA previously extracted for SWOG-8814A (T, CAF-T arms; T, 5 yrs) was analyzed for RNA/library yield (see companion abstract Cherbavaz et al. for methods). Genes were sequenced and expression of mRNA species was related to disease-free survival (DFS) using Cox proportional hazards. Discovery analyses controlled false discovery rate (FDR) at 10%. Genes were identified for prognosis on T and prediction on CAF-T vs T. Networks of genes/pathways were explored. Early (0-5 yrs) and late (5-13+ yrs) time periods were studied. Gene Ontology, Cytoscape, pathway and hierarchical clustering were used for functional gene and metagene analyses.

RESULTS: Of 367 samples, 354 (96%; 142 T, 212 CAF-T; 141 DFS events) had sufficient RNA/library yield, with 20,101 genes sequenced. For prognosis on T, there were 2327 and 568 genes discovered in early and all-yrs follow-up, with only 9 genes prognostic after 5 yrs. Prognosis analyses for residual risk after CAF-T were uninformative. Functional mapping found that genes prognostic for worse DFS were enriched for proliferation (G2M, M-phase), cellular metabolism, DNA repair, stress response and EMT; whereas, those with better DFS involved transcription regulation/repression via zinc finger proteins. Hierarchical clustering (T arm) found significant DFS prognostic metagene signatures for ER-related genes, immune response, ECM/stroma, chromatin remodeling-transcription factor activity and TGFb pathway. All varied for early vs late DFS events. For example, low ER/high stroma expression signatures correlated with high proliferation gene expression and were strongly associated with early events (standardized [st] HR 2.94, p<0.001). Late recurrence was associated with high proliferation, both individually (stHR 1.51, p=.035) and in combination with higher ER expression (stHR 1.51, p=0.09). Fifteen genes predicted CAF benefit (9 better DFS, 6 worse), or 129 genes if FDR relaxed to 20%. Cluster analysis for CAF prediction is ongoing.

CONCLUSIONS: Unique genes, clusters and pathways were identified by NGS of archival material in ER+ N+ breast cancer, including previously unreported signatures. While ER, stroma and proliferation-related signatures were associated with early prognosis, proliferation best predicted worse DFS after 5 yrs. NGS of the primary tumor is most informative for early events in pts with only 5 years of T, with few genes selecting only for late relapse. If validated, these signatures may identify pts with excellent DFS despite positive nodes for endocrine therapy alone as well as others for whom chemotherapy and/or biologics are also required

.

SUPPORT: NCI CA 180888, 180819, 180821, 180820, 180863; in part, Genomic Health, Inc.

Citation Format: Albain KS, Crager MR, Barlow WE, Baehner FL, Bergamaschi A, Rae JM, Ravdin PM, Tripathy D, Gralow JR, Livingston RB, Osborne CK, Ingle JN, Pritchard KI, Davidson NE, Carey LA, Cherbavaz DB, Sing AP, Shak S, Hortobagyi GN, Hayes DF. Molecular predictors of outcome on adjuvant CAF plus tamoxifen (T) vs T in postmenopausal patients (pts) with ER+, node+ breast cancer – Transcriptome expression analysis of the phase III trial SWOG-8814. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S3-02.

Abstract OT3-01-01: HERMIONE: A phase 2, randomized, open label trial comparing MM-302 plus trastuzumab with chemotherapy of physician's choice plus trastuzumab, in anthracycline naive HER2-positive, locally advanced/metastatic breast cancer patients previously treated with pertuzumab and ado-trastuzumab emtansine (T-DM1)

Background: Although HER2-targeted therapies such as pertuzumab and T-DM1 have improved patient outcomes, treatment resistance typically occurs. MM-302 is a HER2-targeted liposomal doxorubicin in development by Merrimack Pharmaceuticals. In a Phase 1 study, patients with HER2-positive metastatic breast cancer (MBC) were treated with MM-302 alone and in combination with trastuzumab with or without cyclophosphamide. MM-302 had an acceptable safety profile and promising efficacy was observed in patients not previously exposed to an anthracycline.

Trial design: HERMIONE (NCT02213744) is a randomized Phase 2, two-arm, open-label trial designed to evaluate if MM-302 can address an unmet medical need in patients with anthracycline naïve, trastuzumab-, pertuzumab- and T-DM1-pretreated HER2-positive locally advanced breast cancer (LABC)/MBC. Patients are randomized 1:1 to receive MM-302 (30mg/m2, Q3W) plus trastuzumab (6mg/kg, Q3W) or chemotherapy of physician's choice (vinorelbine, capecitabine, or gemcitabine) plus trastuzumab (6mg/kg, Q3W).

Eligibility criteria: Centrally confirmed HER2-positive LABC/MBC, no prior anthracycline exposure, prior trastuzumab in any setting, prior pertuzumab and T-DM1 in the LABC/MBC setting, unlimited prior lines of therapy, ECOG 0-1 and LVEF ≥50%. CNS metastases are permitted if stable and without symptoms or steroids for 4 weeks.

Specific aims: The primary endpoint is independently assessed progression free survival (PFS). Secondary endpoints include investigator assessed PFS, overall survival, response rate, safety and patient related outcomes.

Statistics: 250 patients will be enrolled to observe 191 PFS events for 90% power to detect a Hazard Ratio of 0.625. The MM-302 arm will be compared to the control arm on the primary endpoint of PFS using a stratified log-rank test at one-sided 0.025 level.

Accrual status: First patient in was December 2014 and enrollment is expected to be complete in late 2016. Sites are open in the US, Canada and Western Europe and are currently enrolling patients.

Citation Format: Miller K, Cortes J, Hurvitz SA, Krop IE, Tripathy D, Verma S, Riahi K, Reynolds JG, Wickham T, Molnar I, Yardley DA. HERMIONE: A phase 2, randomized, open label trial comparing MM-302 plus trastuzumab with chemotherapy of physician's choice plus trastuzumab, in anthracycline naive HER2-positive, locally advanced/metastatic breast cancer patients previously treated with pertuzumab and ado-trastuzumab emtansine (T-DM1). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-01-01.

Abstract P4-02-05: Predictors of MRI detection of occult lesions in newly diagnosed breast cancer

BACKGROUND: The appropriate use of preoperative magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer remains a topic of debate. We aimed to determine the usefulness of MRI in the detection of occult multicentric, multifocal and contralateral lesions not seen by ultrasound or mammography.

METHODS: We performed a retrospective analysis of consecutive patients who underwent preoperative MRI for newly diagnosed biopsy-proven stage 0-III breast cancer who were treated surgically from January 2006-March 2013. All newly diagnosed breast cancer patients at our two affiliated institutions were evaluated with pre-operative MRI. Patients who received neoadjuvant systemic therapy or surgery at an outside institution were excluded from our study. Demographic, radiographic and pathologic data points including age, race, body mass index (BMI), lesion size, mammographic density, biopsy histology, and biomarkers were assessed for each patient with respect to the findings of multifocality, multicentricity, and the presence of contralateral lesions on all three imaging modalities. We performed univariate analysis associating factors separately in each of three models with multicentric, multifocal and contralateral disease on surgical pathology followed by multivariable analysis using logistic regression to calculate odds ratios.

RESULTS: Of 857 patients undergoing breast MRI within this time period, 770 patients were identified who met inclusion criteria. All patients underwent diagnostic mammogram and ultrasound followed by MRI. The patient population was 44.2% Hispanic, reflective of the population of our two institutions. Mean age was 54.7 years. MRI identified 86 patients with biopsy-proven multicentricity compared to 66 on conventional imaging. MRI identified 170 patients with biopsy-proven multifocality compared to 132 on conventional imaging. Finally, MRI identified 24 patients with biopsy-proven contralateral cancers compared to 7 on conventional imaging. Biopsy histology of invasive lobular carcinoma was predictive of the presence of multifocality on MRI (p=0.038, OR=1.95, 95% CI 1.09-3.48). Mammographic density was found to be a predictor of multicentricity (p=0.015, OR=2.22, 95% CI 1.13-3.33). Lesion size trended towards statistical significance on multivariate analysis of the multicentric lesions (p=0.057, OR=1.88, 95% CI 1.00-3.51). For contralateral cancers seen on MRI the presence of invasive lobular carcinoma on biopsy (p=0.027, OR=4.83, 95% CI 1.25-16.21) was predictive of finding a contralateral cancer.

CONCLUSIONS: Predictive factors including breast density, biopsy histology, and lesion size should be taken into account as clinical predictors of utility of pre-operative breast MRI. This data is being used to construct nomograms to predict multicentric, multifocal and contralateral disease to aid clinicians in evaluating the potential clinical utility of preoperative breast MRI.

Citation Format: Wecsler JS, Raghavendra A, Mack WJ, Tripathy D, Yamashita M, Sheth P, Hovanessian-Larsen L, Sener SF, Russell CA, MacDonald H, Lang JE. Predictors of MRI detection of occult lesions in newly diagnosed breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-02-05.

Abstract P4-14-22: A single-center, open-label phase 1b study of entinostat, and lapatinib alone, and in combination with and trastuzumab in patients with HER2+ metastatic breast cancer after progression on trastuzumab

Background: Our in vitro and in vivo preclinical data showed that entinostat enhances the efficacy of lapatinib in HER2 positive (HER2+) breast cancer cells via FOXO3-mediated Bim1 expression, which resulted in enhanced apoptosis in HER2 targeted therapy (lapatinib and trastuzumab)-resistant breast cancer (IBC and non-IBC) cells [Lee et al.]. Based on these findings, we conducted a phase 1b trial of entinostat to determine the maximal tolerated dose (MTD) in combination with lapatinib alone and in combination with lapatinib and trastuzumab for metastatic HER2+ breast cancer patients (pts), who progressed on trastuzumab.

Method: This was a single-center, open-label phase 1b study to evaluate the dose limiting toxicity (DLT) and determine MTD. 3+3 dose escalation schedule was used for Cohorts 1 and 2. Pts received lapatinib and entinostat (Cohort 1) or entinostat, lapatinib, and trastuzumab (Cohort 2). Initial dose of lapatinib 1250mg in Cohort 1 and 1000mg for Cohort 2 to match standard dose in combination with trastuzumab dose. In Cohort 1, entinostat was given PO on day 1 and 15 every 28 days cycle at dose levels 10 mg (level 0), 12 mg (level 1), or 15 mg (level 2). The dose levels for Cohort 2 were 12 mg (co-level 0) or 15 mg (co-level 1) on day 1 and 15 every 28 days cycle. While lapatinib and entinostat were given 28 days cycle due to entinostat dosing, the dosing of trastuzumab followed approved schedule every 21 days starting at 8mg/kg loading followed by 6mg/kg q 3 wks in Cohort 2 and 3. After the MTD of entinostat in cohort 2 was determined at 12mg, an expansion cohort of 10 pts (cohort 3) was conducted.

Results: Median age was 52 (26-69 yrs). Median number of prior trastuzumab-based regimens was 2 (1-6), 8 pts had lapatinib containing treatment prior to the trial, including 5 pts who had clinical benefit. 16 had ER+ and 13 ER negative, and 9 had IBC. Clinical efficacy and toxicity of treatment is summarized in table 1. Out of 14 pts who had clinical benefit (CR, PR, SD), 6 had IBC. Three pts are still on therapy (1CR, 1PR, 1SD).

Table 1. Clinical Efficacy, Toxicity of combination Receptor StatusResponseGrade 3 toxicityGrade 4 toxicityCohort 1HER2+/ER- (N=8) HER2+/ER+ (N=7)CR (N=1; 8M), SD (N=4;1,2,4M)Lapatinib dose reduction: 3 pts Rash (2) Abdominal pain + dyspnea (1)Entinostat dose reduction: 2pts Neutropenia (1 at 12mg, 1 at 15mg)Cohort 2/3HER2+/ER- (N=8) HER2+/ER+ (N=6)CR (N=2; 3,6M), PR (N=2;4,5M) SD (N=5;1,2,4,6M)Lapatinib dose reduction: 2 pts Diarrhea (N=1 at 12mg N=1 at 10mg) Entinostat dose reduction: 5 pts Neutropenia (N=2 at 12 mg) Leukopenia (N=1 at 12mg) Anemia (N=1 at 12mg)Entinostat dose reduction: 2pts Hypokalemia (N=1 at 12mg) Thrombocytopenia (N=1 at 15mg)CR: complete response, PR: partial response, SD: stable disease, N=number of pts, M=months

Conclusion: MTD was reached at 12mg q 2wkly entinostat, lapatinib 1000 mg daily and trastuzumab 8 mg/kg followed by 6mg/kg q 3 wks. This combination was safe and had promising clinical efficacy in patients with trastuzumab-resistant metastatic HER2+ breast cancer including IBC, warranting further study.

Citation Format: Lim B, Jackson S, Alvarez RH, Ibrahim NK, Willey JS, Murthy RK, Booser DJ, Giordano SH, Barcenas CH, Brewster A, Walters RS, Brown PH, Tripathy D, Valero V, Ueno NT. A single-center, open-label phase 1b study of entinostat, and lapatinib alone, and in combination with and trastuzumab in patients with HER2+ metastatic breast cancer after progression on trastuzumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-22.

Regulatory and effector T cells changes in remission and resistant state of childhood nephrotic syndrome

Idiopathic minimal change disease is a disorder of T-cell dysfunction. The relative predominance of regulatory T cells (Tregs), Th1, and Th2 cells in nephrotic syndrome (NS) remains controversial. Imbalance in peripheral blood regulatory and effector T cells (Teff) are linked to cell mediated immune response and may be associated with steroid response in NS. Peripheral blood CD4 + CD25 + FoxP3 + (Tregs), CD4 + IFN-γ⁺ (Th1), and CD4 + IL-4 + (Th2) lymphocytes were analyzed in 22 steroid-sensitive NS (SSNS) patients in sustained remission, 21 steroid-resistant NS (SRNS) and 14 healthy controls. The absolute percentage values and ratio of Th1/Tregs, Th2/Tregs, and Th1/Th2 were compared between SSNS, SRNS and control subjects. The percentage of Tregs was lower in SRNS patients (P = 0.001) compared with that of SSNS and healthy control. The percentage of Th1 cells was higher in SRNS (P = 0.001) compared to that of SSNS patients; however, it was similar to healthy controls (P = 1.00). The percentage of Th2 cells in SRNS (P = 0.001) was higher as compared to SSNS and controls. The ratio of Th1/Treg cells in SRNS (P = 0.001) was higher as compared to SSNS patients and controls. The ratio of Th2/Treg was also higher in SRNS as compared to SSNS and controls. The ratio of Th1/Th2 cells in SSNS, SRNS, and healthy controls were similar. The cytokines secretion complemented the change in different T-cell subtypes in SSNS, SRNS and healthy controls. However, the IFN-γ secretion in healthy controles was low inspite of similar percentage of Th1 cells among SRNS cases. We conclude that greater ratio of Tregs compared to that Th1 and Th2 favor steroid sensitivity and reverse ratio results in to SRNS. The difference in ratio is related to pathogenesis or it can be used as marker to predict steroid responsiveness needs further evaluation.

The inflammatory status score including IL-6, TNF-α, osteopontin, fractalkine, MCP-1 and adiponectin underlies whole-body insulin resistance and hyperglycemia in type 2 diabetes mellitus

A state of subclinical systemic inflammation is characteristically present in obesity/insulin resistance and type 2 diabetes mellitus (T2DM). The aim of the study was to develop an integrated measure of the circulating cytokines involved in the subclinical systemic inflammation and evaluate its relation with whole-body insulin sensitivity and glucose metabolism in T2DM. T2DM patients (n = 17, M/F 13/4, age = 55.0 ± 1.7 years, BMI = 33.5 ± 1.5 kg/m(2), HbA(1c) = 7.7 ± 0.3%) and normal glucose-tolerant (NGT) subjects (n = 15, M/F 7/8, age = 49.1 ± 2.5 years, BMI = 31.8 ± 1.2 kg/m(2), HbA(1c) = 5.6 ± 0.1%) were studied in a cross-sectional design. Whole-body insulin sensitivity was quantified by the euglycemic clamp. Beta-cell function [disposition index (DI)] was calculated using insulin and glucose values derived from an oral glucose tolerance test and the euglycemic clamp. Body fat mass was evaluated by dual-energy X-ray absorptiometry. Plasma cytokine [TNF-α, IL-6, MCP-1, osteopontin, fractalkine and adiponectin] values were divided into quintiles. A score ranging from 0 (lowest quintile) to 4 (highest quintile) was assigned. The inflammatory score (IS) was the sum of each cytokine score from which adiponectin score was subtracted in each study subject. Inflammatory cytokine levels were all higher in T2DM. IS was higher in T2DM as compared to NGT (10.0 ± 1.1 vs. 4.8 ± 0.8; p < 0.001). IS positively correlated with fasting plasma glucose (r = 0.638, p < 0.001), 1-h plasma glucose (r = 0.483, p = 0.005), 2-h plasma glucose (r = 0.611, p < 0.001) and HbA1c (r = 0.469, p = 0.007). IS was inversely correlated with insulin sensitivity (r = -0.478, p = 0.006) and DI (r = -0.523, p = 0.002). IS did not correlate with BMI and body fat mass. IS was an independent predictor of fasting plasma glucose and had a high sensibility and sensitivity to predict insulin resistance (M/I < 4). A state of subclinical inflammation defined and quantifiable by inflammatory score including TNF-α, IL-6, MCP-1, osteopontin, fractalkine and adiponectin is associated with both hyperglycemia and whole-body insulin resistance in T2DM.

Abstract P1-04-11: Recovery rates of circulating tumor cells in breast cancer cell lines spiked into peripheral blood

Background: Circulating tumor cells (CTCs) have been demonstrated to be prognostic in all stages of breast cancer. Immunomagnetic enrichment followed by fluorescence activated cell sorting (IE/FACS) isolates enriched populations of CTCs derived from peripheral blood without the need for background subtraction of leukocytes. We previously reported IE/FACS as a strategy for gene expression profiling of CTCs. We hypothesized that variable expression of the epithelial cell adhesion marker (EpCAM) may bias IE/FACS recovery rates and composition.

Patients and Methods: 10 breast cancer cell lines were acquired from the ATCC, authenticated by short tandem repeat profiling, and stratified according to subtype: HER2 positive (SKBR3, MDA-MB-453, SUM190), luminal A (T47D, MCF7, ZR751), luminal B (BT474) and basal-like (SUM149, MDA-MB-231, Hs578T). Unknown quantities of cell lines were spiked into PBS or peripheral blood (PB) from healthy female donors. IE/FACS was performed using EpCAM (MJ37) ferrofluid particles via a magnetic separator followed by incubation with Thioflavin T, CD45 PE-Cy7, and EpCAM (EBA-1) mAb conjugated to phycoerythrin. FACS sorting was performed using a FACS Aria II (BD Biosciences) and a gating strategy devised based on negative controls (n = 23). Absolute cell counts and recovery rates were determined using the TruCOUNT method (BD Biosciences) with acquisition of 35,000 beads. Two-way ANOVA was used to analyze variation in recovery rates between groups (Prism GraphPad 6.0).

Results: Overall mean recovery rates for the 10 cell lines were 51.4% from PBS and 39.5% from PB. The specific cell type being analyzed was a more significant source of variation (p = 0.03) than was whether measurements were made from PBS or PB (p = 0.2). However, analysis by molecular subtype did not show differences between intrinsic groups (p = 0.23) nor did it show differences in recovery rates from PBS or PB (p = 0.26). The two inflammatory breast cancer cell lines (SUM 149 and SUM190) showed no differences in recovery rates compared to other cell lines (p = 0.41) nor in recovery rates from PBS versus PB (p = 0.75). Recovery rates for the 10 cell lines are shown in Table 1.

Recovery Rate Recovery from PBS (%)Recovery from PB (%)SKBR368.051MDA-MB-45361.270.6T47D28.911.4MCF794.024.4BT47497.147.6ZR75152.850.8SUM1496372.9SUM19048.358.3MDA-MB-2310.927.04Hs578T0.250.84Recovery rate of immunomagnetic enrichment/fluorescence activated cell sorting of cell lines spiked into saline (PBS) or peripheral blood (PB)

Conclusions: Significant variation occurred in recovery rates of spiked, sorted cells depending on cell line type. Negative control PB specimens from healthy individuals could successfully define a consistent gating strategy that captured zero CTCs from healthy individuals and permitted acquiring a portion of CTCs from each of the 10 cell lines. Further experiments will characterize the gene expression of the sorted cells compared to bulk RNA for each cell line. Better biomarkers are needed to improve upon the recovery rates of CTCs while minimizing selection bias. Future studies are required to determine if expression profiling of CTCs is an informative biomarker that may be applied clinically as a prognostic or predictive tool.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-04-11.

Abstract P5-08-04: Overexpression of CXCR-4 confers trastuzumab resistance in human breast cancer cell lines

Background: Trastuzumab significantly improves survival in patients with HER2 positive breast cancer; however, de novo or acquired resistance ensues in the advanced setting. We have identified differentially expression genes in acquired trastuzumab resistance cell line models following long-term trastuzumab exposure and have demonstrated consistent overexpression of CXCR-4 at the mRNA and protein levels. The interaction between the cognate ligand CXCL-12 and its receptor CXCR-4 is known to promote malignant cell proliferation and angiogenesis via activation of Akt and MAPK pathways. CXCR-4 shows no to low expression in normal breast epithelium while its expression sequentially increases from precancerous lesions to carcinomas. CXCR-4 overexpression in human breast cancer is also associated with a worse outcome in small studies. We sought to explore the role of CXCR-4 expression on trastuzumab drug responsiveness.

Methods: Trastuzumab-resistant cell lines were generated by serial passaging of HER+ cells lines BT-474 and SKBR-3 for 1 year with continual exposure to 200 μg/ml of trastuzumab. For these resistant cell lines, termed BtRT and SkRT, CXCR-4 mRNA was quantified using qRT-PCR, and CXCR-4 protein expression was quantified by Western blot. Stable clones overexpressing CXCR-4 receptor were selected by transfecting CXCR-4 sequence-containing lentivirus into sensitive parental sensitive BT-474 and SKBR3 cells. Expression of CXCR-4 receptor was assessed by Western blot assay and by flow cytometry. MTT cell viability analysis was performed on these transfected cell lines to characterize trastuzumab dose responsiveness with parental cells as control.

Results: Trastuzumab-resistant cell line BtRT demonstrated a 100-fold increase in IC50 to trastuzumab treatment when compared to parental BT-474 cells and also exhibited a 3-fold further increase in CXCR-4 mRNA and a corresponding increase in CXCR-4 protein. CXCR-4-transfected sensitive BT474 cell lines showed a greater than 100 fold increase in the IC50 value on MTT assay after treatment with trastuzumab as compared to the parental cell line. Semi-quantitative analysis by Western-blot confirmed a 5-fold increase in CXCR-4 expression in CXCR-4-transfected cells as compared to parental cells. CXCR-4 expression in HER2+ human breast tumors and responsiveness in patients treated with neoadjuvant trastuzumab-based therapy will be presented.

Conclusion: CXCR-4 overexpression and activation of the CXCR-4/CXCL-12 pathway contributes to trastuzumab resistance in human breast cancer cell lines. CXCR-4 targeting may represent a therapeutic strategy to improve the efficacy of trastuzumab in HER2-positive breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-08-04.

Abstract P1-04-07: Isolation and expression profiling of EpCAM-negative circulating tumor cells in human and xenograft models of breast cancer

Background: While several assays currently exist to enumerate circulating tumor cells (CTCs), limitations to existing assays include reliance on the expression of the cell surface marker epithelial cell adhesion molecule (EpCAM) and difficulty isolating pure populations of rare CTC RNA from peripheral blood without background subtraction of leukocytes. We evaluated the biomarkers CD146 and CD49f as a strategy to isolate CTCs that underwent epithelial to mesenchymal transition (EMT). We hypothesized that using immunomagnetic separation and fluorescence activated cell sorting (IE/FACS) it is possible to isolate RNA derived from EpCAM-negative CTCs.

Methods: 10 breast cancer cell lines were acquired from the ATCC, authenticated by short tandem repeat profiling, and stratified according to subtype: HER2 positive (SKBR3, MDA-MB-453, SUM190), luminal A (T47D, MCF7, ZR751), luminal B (BT474) and basal-like (SUM149, MDA-MB-231, Hs578T). IE/FACS with EMT gates was performed using CD146 ferrofluid particles via a magnetic separator followed by incubation with Thioflavin T, CD 31 and CD45 PE-Cy7 (for human or mouse blood), CD146-V450, and CD49f-A647. FACS sorting was performed using a FACS Aria II (BD Biosciences). Known quantities of cells were spiked into PBS or peripheral blood (PB) from healthy female donors and subjected to IE/FACS with EMT gates. Absolute cell counts and recovery rates were determined using the TruCOUNT method (BD Biosciences) with acquisition of 35,000 beads. MDA-MB-231 xenografts were established in 4 male NOD/SCID/IL2 gamma chain deficient mice; cardiac punctures were performed to acquire a complete xenograft PB volume for IE/FACS. Sorted xenograft CTCs, human PB and MDA-MB-231 were used to isolate RNA, amplify and profile via Affymetrix human gene ST 1.0 arrays. The effect of sample processing with IE/FACS was assessed using our EpCAM gates (EpCAM ferrofluid, EpCAM-PE, thioflavin, CD45 PE-Cy7) to sort BT474 and profiled via next generation sequencing (NGS) using the Helicos Single Molecule sequencing approach.

Results: MDA-MB-231 spiked into PB from an unaffected mouse and negative mouse PB controls were used to establish gating thresholds. This gating strategy recovered 14% of MDA-MB-231 cells from spiked human PB via the TruCOUNT method, which represented a 200% yield versus EpCAM based IE/FACS. CTCs were successfully isolated from 4/4 mice bearing xenografts (ranging from 193-6352 cells captured per ∼1mL mouse blood). Principal component analysis demonstrated that gene expression may differentiate xenograft CTCs from PB and MDA-MB-231. Recovery rates using the EMT gates for 10 cell lines spiked into PBS and human PB will be reported and compared to our typical EpCAM gating strategy. Pearson's correlation coefficient of BT474 spiked into PB and recovered via IE/FACS using an EpCAM gating strategy was 92% by NGS.

Conclusions: We have established a method for the isolation and expression profiling of EpCAM-negative CTCs as well as EpCAM-positive CTCs. Future studies are required to determine if expression profiling of CTCs can be used as prognostic, predictive and discovery tools.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-04-07.

Effect of pioglitazone on body composition and bone density in subjects with prediabetes in the ACT NOW trial

AIMS

This study examined the effects of pioglitazone on body weight and bone mineral density (BMD) prospectively in patients with impaired glucose tolerance as pioglitazone (TZD) increases body weight and body fat in diabetic patients and increases the risk of bone fractures.

METHODS

A total of 71 men and 163 women aged 49.3 (10.7) years [mean (s.d.)]; body mass index (BMI), 34.5 (5.9) kg/m(2) were recruited at five sites for measurements of body composition by dual energy X-ray absorptiometry at baseline and at conversion to diabetes or study end, if they had not converted.

RESULTS

Mean follow-up was 33.6 months in the pioglitazone group and 32.1 months in the placebo group. Body weight increased 4.63 ± 0.60 (m ± s.e.) kg in the pioglitazone group compared to 0.98 ± 0.62 kg in the PIO group (p < 0.0001). Body fat rose 4.89 ± 0.42 kg in the pioglitazone group compared to 1.41 ± 0.44 kg, (p < 0.0001) in placebo-treated subjects. The increase in fat was greater in legs and trunk than in the arms. BMD was higher in all regions in men and significantly so in most. PIO decreased BMD significantly in the pelvis in men and women, decreased BMD in the thoracic spine and ribs of women and the lumbar spine and legs of men. Bone mineral content also decreased significantly in arms, legs, trunk and in the total body.

CONCLUSIONS

Pioglitazone increased peripheral fat more than truncal fat and decreased BMD in several regions of the body.