Abstract P2-05-01: Chemotherapy-induced metastasis: Mechanisms and translational opportunities

1 Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, NY, USA

2 Integrated Imaging Program, Albert Einstein College of Medicine, NY, USA

3 Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, NY, USA

4 Department of Pathology, Albert Einstein College of Medicine, NY, USA

Background: Chemotherapy has become essential in the care of patients with advanced breast cancer. However, as we have previously discovered, chemotherapy may induce pro-metastatic changes in the breast cancer microenvironment by promoting the assembly and function of cancer cell intravasation sites called tumor microenvironment of metastasis (TMEM), and by increasing the proportion of the highly-invasive MenaINV-HI tumor cells that utilize TMEM sites for hematogenous dissemination. Consequently, chemotherapy-treated animals demonstrate increased numbers of circulating-tumor cells and micrometastases. Since the formation of metastases depends on both the presence of functional doorways for dissemination (TMEM) and cancer cells capable of using these doorways (MenaINV-HI tumor cells), we investigated the cellular and molecular contexts required for chemotherapy-mediated induction of TMEM function and MenaINV expression. Since TMEM function depends on Tie2 expressing macrophages and MenaINV expression is inducible by cancer cell -macrophage contact, we focused on inhibiting Tie2 receptors and chemotherapy-induced macrophage influx to inhibit chemotherapy-induced metastasis.

Materials and Methods: We used spontaneous models of mouse breast carcinoma (MMTV-PyMT) and patient-derived xenografts treated with chemotherapy with or without co-treatment with either Tie2 inhibitor (rebastinib), inhibitors of Cxcr4+ macrophage chemotaxis (Cxcl12 inhibitors) or macrophage depletion agents (clodronate). Pro-metastatic endpoints were measured by intravital imaging, multichannel immunofluorescence and standard metastasis dissemination assays.

Results: We demonstrated, using multiple methods of macrophage suppression, that chemotherapy-mediated induction of MenaINV-HI tumor cells depends on the presence of macrophages. In particular, depletion of either the entire macrophage lineage using clodronate liposomes or the use of specific inhibitors of the Cxcl12/Cxcr4 chemotactic pathway, resulted in a significant suppression of the MenaINV-hi cancer cell subpopulation in all mammary tumors examined. Moreover, inhibition of Tie2 by rebastinib blocked TMEM function and decreased the number of circulating tumor cells and metastatic foci, despite the chemotherapy-mediated induction of MenaINV-HI tumor cells.

Conclusions: Our data indicate that both the MenaINV-HI disseminating cancer cell population and the TMEM doorways are necessary but not individually sufficient for metastasis. As such, suppression of either the MenaINV-HI population or TMEM function can suppress chemotherapy-induced metastasis, thus providing a target to improve clinical care and eliminate non-beneficial effects of chemotherapy.

Citation Format: Rivera Sanchez LG, Karagiannis GS, Wang Y, Sharma VP, Burt J, Entenberg D, Oktay M, Condeelis JS. Chemotherapy-induced metastasis: Mechanisms and translational opportunities [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-05-01.

Abstract P2-08-18: Tumor microenvironment of metastasis (TMEM) score in residual breast carcinoma post-neoadjuvant chemotherapy as an independent prognosticator of distant recurrence

Background: Tumor microenvironment of metastasis (TMEM) is a microanatomical structure composed by 3 cells in direct contact, including a tumor cell expressing the actin-regulatory protein Mammalian-enabled (Mena), a perivascular Tie2hi/Vegfhi-expressing macrophage, and an endothelial cell. TMEM are intravasation sites that function as doorways for hematogenous tumor cell dissemination and metastases (Harney et al. Cancer Discovery 2015). TMEM may be identified and enumerated by triple immunohistochemistry in mouse and human mammary carcinomas. High TMEM score is associated with increased risk of distant metastasis in early stage breast cancer, and provides complementary prognostic information to IHC4 (Rohan et al. JNCI 2014) and Oncotype DX Recurrence Score in ER+, HER2-negative breast cancer (Sparano et al. NPJ Breast Cancer, 2017). Neoadjuvant chemotherapy (NAC) increases TMEM score in breast carcinoma in animal models and humans, indicating a previously unrecognized mechanism of resistance to cytotoxic therapy (Karagiannis et al. Science Trans Med 2017). Intravasation at TMEM sites may be inhibited using agents that block release of VEGF from TMEM-associated TIE2-hi, VEGF-hi macrophages (Harney et al. Mol Cancer Ther, 2017). Here we investigated whether TMEM score in post-NAC treated breast carcinoma is prognostic of distant recurrence in localized breast cancer after NAC, and thus provides a foundation for testing agents that block TMEM function in combination with NAC.

Methods: We determined TMEM score in 80 evaluable patients' post-NAC specimens with residual invasive ductal carcinomas of at least 0.5 cm. Approximately 60% of patients had ER+/HER2-negative, 28% had triple negative and 12% had HER2+ disease. Most of the patients received doxorubicin/cyclophosphamide + taxane and an anti-HER2 therapy if applicable. Tissue sections from residual tumors were stained for TMEM using triple immunohistochemistry for Mena-expressing cancer cells, CD31-expressing endothelial cells and CD68-expressing macrophages. The stained slides were scanned, and the images were analyzed by three pathologists, blinded to outcome, who independently determined the tissue areas appropriate for TMEM scoring. TMEM was scored within these areas using an automated algorithm.

Results: TMEM score was significantly higher in patients with distant recurrence (average TMEM=106), compared to patients without distant recurrence (average TMEM=71) (p<0.01, two-sided t-test). Moreover, in a Cox proportional hazards model that included TMEM score (upper tertile vs. lower 2 tertiles), age (>50 yrs. vs. <50), race (black vs non-black), tumor stage (T 1-3), estrogen receptor (ER) status (+ vs -), high TMEM score was associated with a increased risk of distant recurrence (HR=2.2, 95% CI=1.0 to 4.9, p=0.05)

Conclusion: TMEM score may provide independent prognostic information for distant recurrence in patients with residual invasive carcinoma after NAC. These results support the use of agents that block TMEM function in combination with NAC, as planned in the I-SPY2 trial.

Citation Format: Oktay MH, D'Alfonso T, Ginter P, Lanjewar S, Entenberg D, Pastoriza JM, Wang Y, Lin Y, Karagiannnis GS, Lin J, Ye X, Anampa J, Xue X, Rohan TE, Sparano JA, Condeelis JS. Tumor microenvironment of metastasis (TMEM) score in residual breast carcinoma post-neoadjuvant chemotherapy as an independent prognosticator of distant recurrence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-18.

Abstract P2-01-06: Intravital imaging of the lung reveals the efficiency of the metastatic cascade

Background: Breast cancer is the leading cause of cancer related-death in women[1] with over 90% of these deaths due to metastasis. In these cases, the lung is the most common anatomical site of metastasis found at autopsy[2]. For the last 100 years, the process of metastasis has been studied through the use of an experimental metastasis (EM) assay [3] consisting of tail vein injection of tumor cells into tumor-free mice, followed by histopathological analysis of the lung weeks later to gain insight into tumor cell arrival, survival, and the growth of metastases. These studies have concluded that metastasis is an inefficient process[4]. Using a new technology developed at Albert Einstein College of Medicine, called the Window for High Resolution Imaging of the Lung (WHRIL)[5], we have directly compared EM to the more clinically relevant process of tumor cells spontaneously metastasizing (SM) from a primary tumor in situ to the lung and have found significant differences in metastatic efficiency between EM and SM.

Methods: Real-time images of tumor cell dissemination were captured using the WHRIL (Figure 1) in both EM and SM models. Metastatic potential was analyzed, and compared between the models, the percentage of tumor cells surviving in the lung over time, their endothelial crossing-time, their frequency of interaction with macrophages, the fraction of cells which are dormant, and the percent of cells that developed into metastases.

Results: Tumor cells which spontaneously metastasize from primary tumors show a ten-fold higher rate of survival in the lung and three times greater efficiency in forming metastases compared to those directly injected into the lung vasculature. Most of SM tumor cells are dormant indicating that the residual disease phenotype is programmed by the primary tumor either directly in the primary site or indirectly at the secondary site.

Conclusion: These results indicate that experimental metastasis does not accurately reflect the true clinical process and that spontaneous dissemination from a primary tumor has significant influence on the survival and growth of disseminated cells. This suggests that the tumor microenvironment of the primary tumor educates disseminating tumor cells for survival, dormancy and growth at the primary site, and/or prepares the pre-metastatic niche, in the secondary site. Understanding where and how disseminated tumor cells are educated is critical to preventing their survival and growth.at secondary sites. This discovery will open the door to new strategies for the treatment of metastatic tumors to prevent metastatic progression and death.

Citation Format: Coste AH, Boriello L, Wang Y, Oktay M, Condeelis JS, Entenberg D. Intravital imaging of the lung reveals the efficiency of the metastatic cascade [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-01-06.

Abstract P2-05-06: Analytical and clinical validation of a fully automated tissue-based quantitative assay (MetaSite Breast™) to detect the likelihood of distant metastasis in hormone receptor (HR)-positive, HER2-negative early stage breast cancer (ESBC)

Background: MetaSite Breast™ is a validated assay to predict risk of distant breast cancer metastasis in patients with HR+/HER2- ESBC. The assay measures the number of MetaSites defined as tumor microanatomic structures composed of MENA protein expressing tumor cells in contact with CD31+ endothelial cells and CD68+ macrophages. Previous studies have demonstrated that an increased number of these microanatomic structures is associated with distant metastasis (DM) in HR+/HER2- ESBC independent of clinicopathologic features. Analytical validation of MetaSite Breast™ demonstrated precision of 97-99% (repeat image analysis of the same slide) and performance of 91-96% (staining and image analysis of serial tumor sections). We sought to further understand the importance of the MetaSite in predicting distant breast cancer metastasis utilizing a fully automated prognostic assay in an independent large patient cohort.

Methods: We conducted a nested case-control study within a cohort of 3,760 patients diagnosed between 1980 and 2000 with invasive breast cancer from the Kaiser Permanente Northwest health care system. Cases (n=259) were women who developed a subsequent distant metastasis; controls, selected using incidence density sampling, were matched closely to cases (1:1) on age at and calendar year of primary diagnosis. Of the 481 patient tumor samples evaluated in this study, 57% were HR+/HER2-, 19% were triple negative (TN), and 15% were HER2+ disease. Multivariate models were adjusted for clinical factors including: lymph node status, tumor size, tumor grade, and HRT; as well as matching variables: age and year of diagnosis. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression.

Results: In the HR+/HER2- group, MetaSite Score (MS) ranged from 0-357 and the mean was 44.6. MS was a significant predictor of DM (P=0.039) in patients with HR+/HER2- disease. Cut-points based on tertiles of MS in all 259 controls defined intermediate (13-41) and high (>41) risk groups that were significantly associated with risk of DM versus the low risk group (OR=2.24; 95%CI=1.23-4.13, P=0.009) and (OR=2.94; 95%CI=1.62-5.41, P=0.0005), respectively. Univariate estimates of absolute risk of DM with cutoffs based on 90% sensitivity and specificity were 9.4% for the low risk group (MS<7), 14.1% for the intermediate (MS=7-91), and 23.4% for the high (MS>91). When adjusted for clinical factors, estimates of absolute risk of DM were 6.6%, 14.1%, and 33.0% for the low, intermediate, and high risk groups, respectively. A binary cut-point for the high risk group was determined (MS>14) and was significant with a 2-fold higher risk of DM versus the low risk group and adjusted for clinical covariates (P=0.036). MS was not positively associated with DM in TN or HER2+ disease.

Conclusions: MetaSite Breast™ significantly predicted the risk of distant breast cancer metastasis in ESBC patients with HR+/HER2-disease, independent of classical clinicopathologic features.

Citation Format: Donovan MJ, Jones JG, Entenberg DR, Condeelis JS, D'alfonso TM, Gustavson M, Molinaro A, Oktay MH, Xue X, Sparano JA, Peterson MA, Podznyakova O, Rohan TE, Shuber AP, Gertler FB, Ly A, Divelbiss ME, Hamilton DA. Analytical and clinical validation of a fully automated tissue-based quantitative assay (MetaSite Breast™) to detect the likelihood of distant metastasis in hormone receptor (HR)-positive, HER2-negative early stage breast cancer (ESBC) [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 P2-05-06.

Abstract S4-04: Tumor microenvironment of metastasis (TMEM) score is associated with early distant recurrence in hormone receptor (HR) positive, HER2-negative early stage breast cancer (ESBC)

Background: Metastasis is the primary cause of death in ESBC. We have shown in mouse models that a subpopulation of tumor cells expressing invasive Mena isoforms stream, form microanatomic structures (“TMEM”) with endothelial cells and macrophages, intravasate into the circulation at TMEM sites, and metastasize (Harney et al. Cancer Discovery, 2015). Further, TMEM sites (“MetaSites”) are identifiable in human ESBC, and “MetaSite score” [MS] is positively associated with distant recurrence in HR+/HER2- ESBC independent of clinicopathologic features, including IHC4 (Rohan et al. JNCI 2014). Here we determined the association between MS and recurrence in an independent ESBC cohort (E2197; NCT00003519).

Methods: We evaluated primary tumors from 600 patients (median followup 14.8 years) with ESBC (weighted % = 50% T1, 54% N0, 46% N1) treated with surgery and 4 cycles of adjuvant chemotherapy (AC or AT) and endocrine therapy. Grade, ER, PR, and HER2, and Oncotype DX Recurrence Score (RS) were evaluated in central labs (Badve et al. JCO 2008), and MS was determined in a CLIA-certified lab using an analytically validated, fully automated digital pathology/image analysis method that identifies Mena expressing tumor cells in direct contact with CD68+ macrophages and CD31+ endothelial cells (ie, “TMEMs”, or “MetaSites”). The objectives were to determine the association between MS and distant relapse free interval (DRFI) and relapse free interval (RFI). Kaplan-Meier survival curves were used to estimate time-to-event distributions. Cox proportional hazards models were used to assess hazard ratio associated with MS while controlling for covariates, and allowing time-varying association with MS. Both Kaplan-Meier and Cox regression methods addressed stratified sampling by incorporating proper weights. All analyses were performed in R 3.2.3.

Results: MS ranged from 0-199; the weighted mean MS was lower in HR+/HER2- than TN (16.1 vs. 23.8, p=0.001) and HER2+ disease (26.2, p=0.003). MS was not associated with T or N status, and correlated poorly with RS (r=0.29). Proportional hazards models revealed a significant positive association between continuous MS and DRFI (p=0.001) and RFI (p=0.00006) in HR+/HER2- disease in years 0-5 (and by MS tertiles for DRFI [p=0.04] and RFI [p=0.01]), but not after year 5 or in TN or HER2+ disease. Proportional hazards models including clinical covariates (N0 vs. N1; T1 vs. T2; high vs. int. vs. low grade) also revealed significant positive associations for continuous MS with RFI (p=0.04), and borderline association with DRFI (p=0.08). Similar findings for MS (RFI p=0.05;DRFI p=0.10) were noted in a joint model including categorical RS (<18,18-30, >30).

Conclusions: MS, a novel metastasis biomarker reflecting interaction between streaming and metastasizing tumor cells and microenvironment, provides prognostic information complementary to classical clinicopathologic features and RS in HR+/HER2- ESBC. Further evaluation is warranted in order to identify patients at highest risk of recurrence within 5 years most likely to benefit from adjuvant chemotherapy or novel therapies. (Supported by BCRF and NCI CA21115, CA180794, CA23318, CA66636, CA180820).

Citation Format: Sparano JA, Gray R, Oktay MH, Entenberg D, Rohan T, Xue X, Donovan M, Peterson M, Shuber A, Hamilton D, D'Alfonso T, Goldstein LJ, Gerlter F, Davidson N, Condeelis J, Jones J. Tumor microenvironment of metastasis (TMEM) score is associated with early distant recurrence in hormone receptor (HR) positive, HER2-negative early stage breast cancer (ESBC) [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 S4-04.

Abstract PD5-02: Paclitaxel induced mena- and TMEM-mediated pro-metastatic changes in the breast cancer microenvironment

Background: Breast cancer cell intravasation and dissemination occurs specifically at microanatomical structures that we call tumor-microenvironment of metastasis (TMEM), representing direct physical contact between a tumor cell expressing the actin-regulatory protein Mammalian-enabled (Mena), a perivascular Tie2hi/Vegfhi-expressing macrophage, and an endothelial cell (Harney et al. Cancer Discovery 2015). TMEM sites have been identified in mouse and human mammary carcinomas, and both TMEM density (Rohan et al. JNCI 2014) and invasive Mena isoform expression (Agarwal et al. Breast Cancer Res, 2012; Forse et al. BMC Cancer, 2015]) correlates with metastasis in early stage breast cancer. Since cytotoxic agents such as PTX induce influx of bone marrow-derived progenitors that differentiate into Tie2hi/VEGFhi macrophages in the primary tumor, we hypothesized that PTX may potentiate tumor cell invasion and metastasis by inducing the formation of TMEM sites and/or function.

Methods and Results in humans: We analyzed the effect of chemotherapy on TMEM and invasive Mena isoforms in 10 patients with localized breast cancer who had residual disease after neoadjuvant chemotherapy (NAC: weekly paclitaxel followed by dose-dense doxorubicin-cyclophosphamide [AC]), of whom 7 had more than 2-fold increase in TMEM density in residual disease compared with pretreatment. In a separate cohort of 5 patients, NAC produced an acute increase of up to 150-fold in invasive Mena isoforms after 1-2 doses of NAC.

Methods and Results in mice: After our preliminary data in humans, we evaluated effects of PTX in 4 different models, including 2 mouse models (PyMT-spontaneous & transplantation) and 2 patient-derived xenograft (PDX) triple negative models (HT17, HT33). Although PTX delayed primary tumor growth, tumors in PTX-treated mice had significantly more TMEM sites, circulating tumor cells (CTCs) and metastatic foci when compared to vehicle-treated animals. Using intravital imaging of MMTV-PyMT-Dendra2/Cfms-CFP mice, PTX induced influx of macrophages into primary tumors and intravasation of cancer cells at TMEM sites. Furthermore, PTX treatment significantly increased expression of Mena at the gene and protein levels, including invasive Mena isoforms. Deletion of the Mena gene completely abolished dissemination and metastasis in all cases, including those treated with PTX.

Conclusions: We show in mammary carcinoma mouse models and PDX models that although PTX delays tumor growth, it induces invasive Mena isoform expression and significantly increases the density of TMEM sites that are responsible for cancer cell intravasation, dissemination and metastasis. Thus, our data indicate that PTX paradoxically induces dissemination of breast cancer cells by promoting invasive Mena isoforms and TMEM-mediated cancer cell intravasation, suggesting that blockade of TMEM assembly and/or function could enhance the effectiveness of PTX and possibly other cytotoxic agents commonly used to treat early and advanced stage breast cancer.

Citation Format: Karagiannis GS, Pastoriza JM, Wang Y, Harney AS, Entenberg D, Pignatelli J, Jones JG, Anampa J, Sparano JA, Rohan TE, Condeelis JS, Oktay MH. Paclitaxel induced mena- and TMEM-mediated pro-metastatic changes in the breast cancer microenvironment [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 PD5-02.