Liver Metastatic Breast Cancer Research Articles

The Objective Response and Disease Control Rates in Patients with Liver Metastastic Breast Cancer Receiving Transarterial Radioembolization: A Meta-Analysis.

To meta-analyze the utility of transarterial radioembolization (TARE) in patients with liver metastatic breast cancer (BC), based on the objective response rate (ORR) and disease control rate (DCR). A literature search was performed retrieving studies with (1) at least 10 patients with liver metastatic BC treated with TARE and (2) adequate information to derive ORR and DCR. The ORR is the ratio between patients with liver lesions showing complete response (CR) or partial response (PR) over the total number of patients treated with TARE; the DCR is the ratio between patients with CR, PR, or stable disease (SD) over the total number of patients treated with TARE. Eighteen studies (650 patients) were eligible; the ORR of TARE resulted 50.71% (95% C.I.: 40.04-61.36) and the DCR resulted 88.37% (95% C.I.: 81.89-93.57). Taking into account resin spheres (395 patients), the ORR was 60.35% (95% C.I.: 46.55-73.36) and the DCR was 92.73% (95% C.I.: 87.17-96.80%). Considering glass spheres (144 patients), the ORR was 32.38% (95% C.I.: 18.43-48.16) and the DCR was 82.69% (95% C.I.: 59.29-97.26). This meta-analysis favors the use of TARE in patients with liver metastatic BC either with resin or glass spheres.

Metastatic breast cancer cells are metabolically reprogrammed to maintain redox homeostasis during metastasis

Metabolic rewiring is essential for tumor growth and progression to metastatic disease, yet little is known regarding how cancer cells modify their acquired metabolic programs in response to different metastatic microenvironments. We have previously shown that liver-metastatic breast cancer cells adopt an intrinsic metabolic program characterized by increased HIF-1α activity and dependence on glycolysis. Here, we confirm by in vivo stable isotope tracing analysis (SITA) that liver-metastatic breast cancer cells retain a glycolytic profile when grown as mammary tumors or liver metastases. However, hepatic metastases exhibit unique metabolic adaptations including elevated expression of genes involved in glutathione (GSH) biosynthesis and reactive oxygen species (ROS) detoxification when compared to mammary tumors. Accordingly, breast-cancer-liver-metastases exhibited enhanced de novo GSH synthesis. Confirming their increased capacity to mitigate ROS-mediated damage, liver metastases display reduced levels of 8-Oxo-2′-deoxyguanosine. Depletion of the catalytic subunit of the rate-limiting enzyme in glutathione biosynthesis, glutamate-cysteine ligase (GCLC), strongly reduced the capacity of breast cancer cells to form liver metastases, supporting the importance of these distinct metabolic adaptations.Loss of GCLC also affected the early steps of the metastatic cascade, leading to decreased numbers of circulating tumor cells (CTCs) and impaired metastasis to the liver and the lungs. Altogether, our results indicate that GSH metabolism could be targeted to prevent the dissemination of breast cancer cells.

Single-cell transcriptomics reveals the role of antigen presentation in liver metastatic breast cancer

Liver metastasis (LM) is the primary cause of cancer-related mortality in late-stage breast cancer (BC) patients. Here we report an in-depth analysis of the transcriptional landscape of LM of 11 patients with secondary hepatic carcinoma at single-cell resolution. Our study reveals that terminally exhausted CD4+ and dysfunctional CD8+ Tcells were enriched in LM along with low antigen presentation. We also found that macrophages were associated with the tumor infiltrating CD4+ Tcells, while FCN3+ macrophages, type 1 conventional dendritic cells (cDC1) and LAMP3+ DC regulated Tcell functions, probably via antigen processing and presentation. Major histocompatibility complex expression in FCN3+ macrophage, cDC1 and LAMP3+ DC was reduced in LM compared to those in normal tissues and primary BC. Malfunctioned antigen presentation in these cells is linked to a worse prognosis in invasive BC and hepatocellular carcinoma. Our results provide valuable insights into the role of tumor infiltrating Tcells in LM.

The mechanism of exosome delivered circ-PDE7B promoting liver metastasis of breast cancer.

e13016 Background: According to “seed and soil” hypothesis, tumor microenvironments have major effects on the survival and metastasis of cancers, including breast cancer. Importantly, exosomes are believed to partake in cellular communications through delivering oncogenic ncRNAs (including circRNAs) to the recipient cells and tumor microenvironment, which resulting in distant metastasis. Unfortunately, exosomes delivering circRNAs from breast cancer cells still remained many potential functions that are not completely understood in the progression of liver metastasis of breast cancer. This study aims to provide a theoretical basis to use stable exosomal circRNAs as new biomarkers and target spot for the liver metastasis of breast cancer. Methods: A strategy combining RNA-sequencing technique, RT-qPCR and bioinformatic analysis were used to determine the level of differential expressed circRNAs in tissue exosomes (n=5) and serum exosomes samples (n=5) from liver metastatic breast cancer patients compared with healthy person. The expression of circPDE7B was also detected in tumor tissues (n=10) from liver metastatic patients compared with healthy person, breast cancer cell lines (MDA-MB-231), high-liver metastatic cell lines (LM-MDA-MB-231), exosome from MDA-MB-231 (231/exo) and from LM-MDA-MB-231 (LM-231/exo) by RT-qPCR. In animal experiments, exosomes (enriched in circPDE7B) were injected from tail vein for 24h, follow up with injection with LM-MDA-MB-231 cells, then, fluorescence imaging and pathology showed the metastasis in liver. Results: Isolated serum exosomes were characterization by transmission electron microscope (TEM) and Nanosight 300 (NTA 300) system. We profiled the circRNAs in the tissue and serum exosomes samples from liver metastatic patients and healthy person by RNA sequencing and detected 332 significantly differentially-expressed circRNAs. After bioinformatic analysis with GEO database, circPDE7B was chose to further study. RT-qPCR results showed that higher expression of circPDE7B in liver metastatic tissue and LM-MDA-MB-231, also in LM-231/exo. Moreover, overexpressed circPDE7B in exosomes from breast cancer changes premetastatic microenvironment of the liver microenvironment, which can promote the occurrence of breast cancer liver metastasis. Conclusions: The expression of circPDE7B was found significantly upregulated in tissue and serum exosomes from liver metastatic breast cancer patients. Moreover, circPDE7B could promote liver metastasis of breast cancer. Therefore, this study provides a fresh perspective on novel therapeutic targets and potential biomarkers for liver metastasis from exosomal circRNAs.

IL-6 as a predictor of survival rate in liver metastatic breast cancer patients with Covid-19 infection: A case series

Introduction and importanceBreast cancer is the most common type of cancer in women, with 30 % being metastatic breast cancer. Cancer is known to be a comorbid Covid-19 infection. Interleukin-6 (IL-6) is one of the findings of inflammatory activity due to Covid-19 infection. We report IL-6 levels as a prognostic factor for survival rate in patients with liver metastatic breast cancer. Case presentationWe report five cases of liver metastatic breast cancer with various types of primary breast cancer. All patients are infected with Covid-19. IL-6 levels were reported to be elevated in all five patients. All patients were treated according to the national guidelines for the care of Covid-19 patients. All patients are reported to have deceased after being treated for Covid-19 infection. Clinical discussionMetastatic breast cancer has a low prognostic rate. Cancer has been recognized as one of the comorbidities and increases the severity and mortality of Covid-19 infection. Elevated levels of IL-6 are caused by an immune response to infection, and can worsen the outcome of breast cancer patients. Changes in IL-6 levels implicate the survival rate of metastatic breast cancer patients and outcomes during the treatment of Covid-19 infection. ConclusionElevated levels of IL-6 can be a prognostic factor of the survival rate of metastatic breast cancer patients during the treatment of Covid-19 infection.

Ezrin accelerates breast cancer liver metastasis through promoting furin-like convertase-mediated cleavage of Notch1.

Ezrin, known as a crosslinker between the plasma membrane and actin cytoskeleton, is closely associated with breast cancer (BC) progression. Here, we explored a novel role of ezrin in breast cancer liver metastasis (BCLM). The clinical relevance of ezrin was evaluated using in silico tools and confirmed in BC specimens. The effect of ezrin on proliferation, migration and invasion was examined in vitro and in vivo using murine primary liver-metastatic breast cancer cells (mLM). The molecular mechanism involved in ezrin-mediated activation of the Notch1 signaling pathway was elucidated using in vitro models. Data-mining demonstrated that ezrin mRNA and protein expression is up-regulated in breast cancer cohorts and has prognostic significance. Ezrin overexpression promotes cell proliferation, migration and invasion in vitro and in vivo. Hairy and enhancer of split-1 (Hes1) is one of the most significantly enriched candidates of differentially expressed genes in ezrin overexpression and control mLM cells. Ezrin can positively regulate Hes1 mRNA and protein expression, and their coexpression was associated with poor prognosis in BC patients. Ezrin promoted BC cell proliferation in a Hes1-dependent manner without directly interacting with Hes1. The functional link between ezrin and Hes1 is dependent on Notch1 activation through promotion of furin-like convertase cleavage. Our results demonstrated that ezrin drives BCLM through activation of the Notch signaling pathway via furin-like convertase. These findings provide a better understanding of the mechanism of ezrin in breast cancer progression, with the goal of discovering a novel target for the treatment of BCLM in the future.

The FUS/circEZH2/KLF5/ feedback loop contributes to CXCR4-induced liver metastasis of breast cancer by enhancing epithelial-mesenchymal transition

BackgroundMetastasis of breast cancer have caused the majority of cancer-related death worldwide. The circRNAs are associated with tumorigenesis and metastasis in breast cancer according to recent research. However, the biological mechanism of circRNAs in liver metastatic breast cancer remains ambiguous yet.MethodsMicroarray analysis of three pairs of primary BC tissues and matched hepatic metastatic specimens identified circEZH2. We used RT-qPCR and FISH assays to confirm circEZH2 existence, characteristics, and expression. Both in vivo and in vitro, circEZH2 played an oncogenic role which promoted metastasis as well. A range of bioinformatic analysis, Western blot, RNA pull-down, RIP, ChIP, and animal experiments were used to define the feedback loop involving FUS, circEZH2, miR-217-5p, KLF5, FUS, CXCR4 as well as epithelial and mesenchymal transition.ResultsIn our research, circEZH2 was proved to be upregulated in liver metastases in BC and predicted the worse prognosis in breast cancer patients. Overexpression of circEZH2 notably accentuated the vitality and invasion of BC cells, whereas knockdown of circEZH2 elicited the literally opposite effects. Besides, overexpressed circEZH2 promoted tumorigenesis and liver metastasis in vivo. Moreover, circEZH2 could adsorb miR-217-5p to upregulate KLF5 thus leading to activate FUS transcription which would facilitate the back-splicing program of circEZH2. Meanwhile, KLF5 could upregulated CXCR4 transcriptionally to accelerate epithelial and mesenchymal transition of breast cancer.ConclusionsConsequently, a novel feedback loop FUS/circEZH2/KLF5/CXCR4 was established while circEZH2 could be novel biomarker and potential target for BC patients’ therapy.

Liver Metastatic Breast Cancer: Epidemiology, Dietary Interventions, and Related Metabolism.

The median overall survival of patients with metastatic breast cancer is only 2–3 years, and for patients with untreated liver metastasis, it is as short as 4–8 months. Improving the survival of women with breast cancer requires more effective anti-cancer strategies, especially for metastatic disease. Nutrients can influence tumor microenvironments, and cancer metabolism can be manipulated via a dietary modification to enhance anti-cancer strategies. Yet, there are no standard evidence-based recommendations for diet therapies before or during cancer treatment, and few studies provide definitive data that certain diets can mediate tumor progression or therapeutic effectiveness in human cancer. This review focuses on metastatic breast cancer, in particular liver metastatic forms, and recent studies on the impact of diets on disease progression and treatment.

Intra-Arterial Therapies for Liver Metastatic Breast Cancer: A Systematic Review and Meta-Analysis.

Performing a systematic review and meta-analysis to assess the evidence of intra-arterial therapies in liver metastatic breast cancer (LMBC) patients. A systemic literature search was performed in PubMed, EMBASE, SCOPUS for studies regarding intra-arterial therapies in LMBC patients. Full text studies of LMBC patients (n ≥ 10) published between January 2010 and December 2020 were included when at least one outcome among response rate, adverse events or survival was available. Response rates were pooled using generalized linear mixed models. A weighted estimate of the population median overall survival (OS) was obtained under the assumption of exponentially distributed survival times. A total of 26 studies (1266 patients) were included. Eleven articles reported on transarterial radioembolization (TARE), ten on transarterial chemoembolization (TACE) and four on chemo-infusion. One retrospective study compared TARE and TACE. Pooled response rates were 49% for TARE (95%CI 32-67%), 34% for TACE (95%CI 22-50%) and 19% for chemo-infusion (95%CI 14-25%). Pooled median survival was 9.2months (range 6.1-35.4months) for TARE, 17.8months (range 4.6-47.0) for TACE and 7.9months (range 7.0-14.2) for chemo-infusion. No comparison for OS was possible due to missing survival rates at specific time points (1 and 2year OS) and the large heterogeneity. Although results have to be interpreted with caution due to the large heterogeneity, the superior response rate of TARE and TACE compared to chemo-infusion suggests first choice of TARE or TACE in chemorefractory LMBC patients. Chemo-infusion could be considered in LMBC patients not suitable for TARE or TACE. 3a.

Impact of Pharmaceutical Prophylaxis on Radiation-Induced Liver Disease Following Radioembolization.

Simple SummaryRadioembolization has failed to prove survival benefit in randomized trials, and, depending on various factors including tumor biology, response rates may vary considerably. Studies showed positive correlations between survival and absorbed tumor dose. Therefore, increasing currently prescribed tumor doses may be favorable for improving patient outcomes. The dominant limiting factor for increasing RE dose prescriptions is the relatively low tolerance of liver parenchyma to radiation with the possible consequence of a radiation-induced liver disease. Advances in RILD prevention may help increasing tolerable radiation doses to improve patient outcomes. Our study aimed to evaluate the impact of post-therapeutic RILD-prophylaxis in a cohort of intensely pretreated liver metastatic breast cancer patients. The results of this study as well as pathophysiological considerations warrant further investigations of RILD prophylaxis to increase dose prescriptions in radioembolization.Background: Radioembolization (RE) with yttrium-90 (90Y) resin microspheres yields heterogeneous response rates in with primary or secondary liver cancer. Radiation-induced liver disease (RILD) is a potentially life-threatening complication with higher prevalence in cirrhotics or patients exposed to previous chemotherapies. Advances in RILD prevention may help increasing tolerable radiation doses to improve patient outcomes. This study aimed to evaluate the impact of post-therapeutic RILD-prophylaxis in a cohort of intensely pretreated liver metastatic breast cancer patients; Methods: Ninety-three patients with liver metastases of breast cancer received RE between 2007 and 2016. All Patients received RILD prophylaxis for 8 weeks post-RE. From January 2014, RILD prophylaxis was changed from ursodeoxycholic acid (UDCA) and prednisolone (standard prophylaxis [SP]; n = 59) to pentoxifylline (PTX), UDCA and low-dose low molecular weight heparin (LMWH) (modified prophylaxis (MP); n = 34). The primary endpoint was toxicity including symptoms of RILD; Results: Dose exposure of normal liver parenchyma was higher in the modified vs. standard prophylaxis group (47.2 Gy (17.8–86.8) vs. 40.2 Gy (12.5–83.5), p = 0.017). All grade RILD events (mild: bilirubin ≥ 21 µmol/L (but <30 μmol/L); severe: (bilirubin ≥ 30 µmol/L and ascites)) were observed more frequently in the SP group than in the MP group, albeit without significance (7/59 vs. 1/34; p = 0.140). Severe RILD occurred in the SP group only (n = 2; p > 0.1). ALBI grade increased in 16.7% patients in the MP and in 27.1% patients in the SP group, respectively (group difference not significant); Conclusions: At established dose levels, mild or severe RILD events proved rare in our cohort. RILD prophylaxis with PTX, UDCA and LMWH appears to have an independent positive impact on OS in patients with metastatic breast cancer and may reduce the frequency and severity of RILD. Results of this study as well as pathophysiological considerations warrant further investigations of RILD prophylaxis presumably targeting combinations of anticoagulation (MP) and antiinflammation (SP) to increase dose prescriptions in radioembolization.

C3a elicits unique migratory responses in immature low-density neutrophils.

Neutrophils represent the immune system's first line of defense and are rapidly recruited into inflamed tissue. In cancer associated inflammation, phenotypic heterogeneity has been ascribed to this cell type, whereby neutrophils can manifest anti- or pro-metastatic functions depending on the cellular/micro-environmental context. Here, we demonstrate that pro-metastatic immature low-density neutrophils (iLDNs) more efficiently accumulate in the livers of mice bearing metastatic lesions compared with anti-metastatic mature high-density neutrophils (HDNs). Transcriptomic analyses reveal enrichment of a migration signature in iLDNs relative to HDNs. We find that conditioned media derived from liver-metastatic breast cancer cells, but not lung-metastatic variants, specifically induces chemotaxis of iLDNs and not HDNs. Chemotactic responses are due to increased surface expression of C3aR in iLDNs relative to HDNs. In addition, we detect elevated secretion of cancer-cell derived C3a from liver-metastatic versus lung-metastatic breast cancer cells. Perturbation of C3a/C3aR signaling axis with either a small molecule inhibitor, SB290157, or reducing the levels of secreted C3a from liver-metastatic breast cancer cells by short hairpin RNAs, can abrogate the chemotactic response of iLDNs both in vitro and in vivo, respectively. Together, these data reveal novel mechanisms through which iLDNs prefentially accumulate in liver tissue harboring metastases in response to tumor-derived C3a secreted from the liver-aggressive 4T1 breast cancer cells.

Sequential intra-arterial infusion of 90Y-resin microspheres and mitomycin C in chemo refractory liver metastatic breast cancer patients: a single centre pilot study.

BackgroundThe aim of the study was to evaluate the safety and feasibility of intra-arterial mitomycin C (MMC) infusion after selective internal radiation therapy (SIRT) using Yttrium-90 (90Y) resin microspheres in liver metastatic breast cancer (LMBC) patients.Patients and methodsThe prospective pilot study included LMBC patients from 2012–2018. Patients first received infusion of 90Y resin microspheres, after 6–8 weeks response to treatment was assessed by MRI, 18F-FDG PET/CT and laboratory tests. After exclusion of progressive disease, MMC infusion was administrated 8 weeks later in different dose cohorts; A: 6 mg in 1 cycle, B: 12 mg in 2 cycles, C: 24 mg in 2 cycles and D: maximum of 72 mg in 6 cycles. In cohort D the response was evaluated after every 2 cycles and continued after exclusion of progressive disease. Adverse events (AE) were reported according to CTCAE version 5.0.ResultsSixteen patients received 90Y treatment. Four patients were excluded for MMC infusion, because of extra hepatic disease progression (n = 3) and clinical and biochemical instability (n = 1). That resulted in the following number of patient per cohort; A: 2, B: 1, C: 3 and D: 6. In 4 of the 12 patients (all cohort D) the maximum dose of MMC was adjusted due biochemical toxicities (n = 2) and progressive disease (n = 2). One grade 3 AE occurred after 90Y treatment consisting of a gastrointestinal ulcer whereby prolonged hospitalization was needed.ConclusionsSequential treatment of intra-arterial infusion of MMC after 90Y SIRT was feasible in 75% of the patients when MMC was administrated in different escalating dose cohorts. However, caution is needed to prevent reflux after 90Y SIRT in LMBC patients.

N-Dihydrogalactochitosan Potentiates the Radiosensitivity of Liver Metastatic Tumor Cells Originated from Murine Breast Tumors.

Radiation is a widely used therapeutic method for treating breast cancer. N-dihydrogalactochitosan (GC), a biocompatible immunostimulant, is known to enhance the effects of various treatment modalities in different tumor types. However, whether GC can enhance the radiosensitivity of cancer cells remains to be explored. In this study, triple-negative murine 4T1 breast cancer cells transduced with multi-reporter genes were implanted in immunocompetent Balb/C mice to track, dissect, and identify liver-metastatic 4T1 cells. These cells expressed cancer stem cell (CSC) -related characteristics, including the ability to form spheroids, the expression of the CD44 marker, and the increase of protein stability. We then ex vivo investigated the potential effect of GC on the radiosensitivity of the liver-metastatic 4T1 breast cancer cells and compared the results to those of parental 4T1 cells subjected to the same treatment. The cells were irradiated with increased doses of X-rays with or without GC treatment. Colony formation assays were then performed to determine the survival fractions and radiosensitivity of these cells. We found that GC preferably increased the radiosensitivity of liver-metastatic 4T1 breast cancer cells rather than that of the parental cells. Additionally, the single-cell DNA electrophoresis assay (SCDEA) and γ-H2AX foci assay were performed to assess the level of double-stranded DNA breaks (DSBs). Compared to the parental cells, DNA damage was significantly increased in liver-metastatic 4T1 cells after they were treated with GC plus radiation. Further studies on apoptosis showed that this combination treatment increased the sub-G1 population of cells, but not caspase-3 cleavage, in liver-metastatic breast cancer cells. Taken together, the current data suggest that the synergistic effects of GC and irradiation might be used to enhance the efficacy of radiotherapy in treating metastatic tumors.

Intra-arterial Mitomycin C infusion in a large cohort of advanced liver metastatic breast cancer patients: safety, efficacy and factors influencing survival.

The aim of this study was to determine the safety and efficacy of Mitomycin C (MMC) infusion in a large cohort of advanced liver metastatic breast cancer patients (LMBC) and to determine factors influencing overall survival (OS). We retrospectively analysed LMBC patients, treated with MMC infusion between 2000 and 2017. Hepatic response was measured with baseline CT scans and first available CT scan after MMC infusion by RECIST 1.1 criteria. Adverse events were registered by the CTCAE version 5.0. OS and hepatic progression free survival (hPFS) were evaluated using Kaplan-Meier estimates. After univariable analysis, a stepwise forward multivariable (MV) prediction analysis was developed to select independent pre-treatment factors associated with OS. We included 176 patients with a total of 599 MMC infusions, mostly heavily pre-treated patients with a median time from diagnosis of MBC to MMC infusion of 36.9months. RECIST evaluation of liver lesions (n = 132) showed a partial response rate of 15%, stable disease of 43% and progressive disease in 17%. Adverse events grade 3 and 4 were reported in 17.5%. Median PFS was 5.5months and median OS was 7.8months. Significant independent baseline predictors of worse OS included number of prior systemic chemotherapy lines, prior liver ablation, higher liver tumour burden and elevated levels of bilirubin and ALT. MMC infusion is safe and effective in advanced LMBC patients. An increased number of prior therapies, a higher liver tumour burden and elevated levels of bilirubin and ALT were associated with a worse OS.

Afadin cooperates with Claudin-2 to promote breast cancer metastasis.

Claudin-2 promotes breast cancer liver metastasis by enabling seeding and early cancer cell survival. We now demonstrate that the PDZ-binding motif of Claudin-2 is necessary for anchorage-independent growth of cancer cells and is required for liver metastasis. Several PDZ domain-containing proteins were identified that interact with the PDZ-binding motif of Claudin-2 in liver metastatic breast cancer cells, including Afadin, Arhgap21, Pdlim2, Pdlim7, Rims2, Scrib, and ZO-1. We specifically examined the role of Afadin as a potential Claudin-2-interacting partner that promotes breast cancer liver metastasis. Afadin associates with Claudin-2, an interaction that requires the PDZ-binding motif of Claudin-2. Loss of Afadin also impairs the ability of breast cancer cells to form colonies in soft agar and metastasize to the lungs or liver. Immunohistochemical analysis of Claudin-2 and/or Afadin expression in 206 metastatic breast cancer tumors revealed that high levels of both Claudin-2 and Afadin in primary tumors were associated with poor disease-specific survival, relapse-free survival, lung-specific relapse, and liver-specific relapse. Our findings indicate that signaling downstream from a Claudin-2/Afadin complex enables the efficient formation of breast cancer metastases. Moreover, combining Claudin-2 and Afadin as prognostic markers better predicts the potential of breast cancer to metastasize to soft tissues.

Abstract P5-05-06: Development of advanced pre-clinical in vivo models of metastatic breast cancer

Abstract Backgrounds: The fact that we continue to lose 40,000 women with breast cancer every year in the US despite the recent advance in basic research clearly demonstrate disconnect in translation of basic research findings to clinic. This is largely due to lack of appropriate animal model that mimic clinical conditions for preclinical studies that result in high failure rate of clinical trials. To date, we had established many syngeneic mouse models, which are not free from limitations; 1) few clinically relevant animal models with bone metastasis have been established, 2) syngeneic mouse model cannot address human cancer genomics and tumor heterogeneity. Patient-Derived Xenograft (PDX) model has emerged as pre-clinical model to address these issues, however, it suffers low tumor take rate of around 20-40%, and lack metastatic model. Here, we describe development of orthotopic implantation, and bone and liver metastatic breast cancer mouse models to overcome these limitations. Methods: 1) 4T1.2-luc3 cells that has metastatic potential to the bone were orthotropically inoculated as a syngeneic mouse model, imaged with IVIS and MRI. 2) Patient tumor tissues of 1mm(3) were implanted surgically into dorsal subcutaneous space (SQ), or orthotropically into mammary fat pat #2 and #4 (MFP). Results: 1) We established a syngeneic breast cancer bone metastasis model. Primary tumors were surgically resected days after 4T1.2-luc3 cells were orthotopically implanted under direct vision. Removal of primary tumor allowed bioluminescent visualization and quantification of bone metastasis by IVIS. We found that MRI was effective in evaluating bone metastasis and bone related events in these mice. MRI allows differentiation of bone metastasis from metastasis to the surrounding organs with bone destruction image, whereas conventional bioluminescence imaging shows only existence of cancer cells. 2) The overall tumor take rate of the tumor in PDX model was 46.0% (74/161 implantation site). Take rate from triple-negative breast cancer tumors was 56.1% (74/132), on the other hand, that from ER positive tumors was 0% (0/39). Tumor take rate was significantly better in MFP implantation than SQ (39.5%, 30/76 vs 51.2%, 44/85, p&amp;lt;0.01). Tumor weight were significantly heavier in MFP compared to SQ (0.072g vs 0.328g, p&amp;lt;0.00001). With more passage, the difference in tumor weight between SQ and MFP was significantly increased(p&amp;lt;0.0001). Finally, we developed a PDX breast cancer liver metastasis model by surgically implanting tissue fragment into liver using direct vision technique. We found MRI to be very useful as a living imaging modality to evaluate cancer progression in the deeply located metastatic sites of PDX models. Conclusions: We have established orthotropic syngeneic breast cancer bone metastasis model as well as improved breast cancer PDX model with synchronous liver metastasis utilizing MRI. Our novel models could be powerful tools for preclinical studies. Citation Format: Okano M, Kawaguchi T, Okano I, Katsuta E, Takabe K. Development of advanced pre-clinical in vivo models of metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-05-06.

PDK1-Dependent Metabolic Reprogramming Dictates Metastatic Potential in Breast Cancer

Metabolic reprogramming is a hallmark of cellular transformation, yet little is known about metabolic changes that accompany tumor metastasis. Here we show that primary breast cancer cells display extensive metabolic heterogeneity and engage distinct metabolic programs depending on their site of metastasis. Liver-metastatic breast cancer cells exhibit a unique metabolic program compared to bone- or lung-metastatic cells, characterized by increased conversion of glucose-derived pyruvate into lactate and a concomitant reduction in mitochondrial metabolism. Liver-metastatic cells displayed increased HIF-1α activity and expression of the HIF-1α target Pyruvate dehydrogenase kinase-1 (PDK1). Silencing HIF-1α reversed the glycolytic phenotype of liver-metastatic cells, while PDK1 was specifically required for metabolic adaptation to nutrient limitation and hypoxia. Finally, we demonstrate that PDK1 is required for efficient liver metastasis, and its expression is elevated in liver metastases from breast cancer patients. Our data implicate PDK1 as a key regulator of metabolism and metastatic potential in breast cancer.

A role for hepatic surgery in patients with liver metastatic breast cancer: review of literature.

Traditionally, patients with metastatic breast cancer were seen as carrying a grim prognosis and therapy was based mainly on palliative chemotherapy and hormonal therapy, with surgery being considered as ineffective. However, in the last 20 years different centers worldwide published series of metastatic breast cancer patients who underwent resection for different metastatic sites (liver, brain, lung), reporting favorable results. Most of these papers addressed to the role of liver surgery in patients with breast cancer liver metastases, mainly due to the favorable results achieved by liver resection in patients with metastatic colorectal cancer. In this review are presented the results achieved by liver surgery in patients with breast cancer liver metastases.

HER2 amplification and overexpression between primary and liver metastatic breast cancer: Significance and implication.

150 Background: The systemic management of metastatic breast cancer (MBC) is mostly based on the ER or HER2 status of the primary tumor. However, the hormonal status or the amplificaction/overexpression HER2 may change in every metastatic site because of the effects of the long-term treatment of metastatic cancer with endocrine therapy, chemotherapy, or targeted agents. The purpose of this study was to investigate the frequency of change in HER2 expression in primary and distant metastatic tumors (especially in liver) in HER2+ breast cancer patients. Methods: We retrospectively analyzed the results of 31 consecutive metastatic breast cancer patients that were seen in our center over 4 months from February 2014 through May 2014. All patients were rebiopsied after consultation and samples were sent for standard immunohistochemistry (IHC) for ER, PR, and HER2 and formalin-fixed, paraffin-embedded (FFPE) samples were sent for genomic (Foundation Medicine) and proteomic analysis (Theranostics). All results from the metastatic samples were compared to the baseline IHC and/or FISH results for HER2. Results: A change in HER2 status was observed in 26% of the cases. 16% of cases underwent a negative to positive conversion in HER2 status while 10% of cases underwent a positive to negative conversion. It is notable that all 5 patients that underwent a negative to positive conversion in HER2 status had biopsies taken from metastatic disease in the liver. Overall, 45% of patients with metastatic disease in the liver had a negative to positive conversion in HER2 status. Conclusions: The results of this study emphasize the significance of confirming HER2 expression in a recurrence lesion. This discordance may be due to the increasing level of genetic instability occurring throughout disease progression that can significantly influence the alterations of the HER2 gene. If feasible, HER2 reassessment in metastatic lesions should be carefully taken into account, especially for metastases coming from non-HER2 amplified breast cancer. Although HER2 status is usually appraised in primary tumor, knowledge of the HER2 status in metastases may be of potential value for therapeutic decision making.

Claudin-2 Promotes Breast Cancer Liver Metastasis by Facilitating Tumor Cell Interactions with Hepatocytes

We previously identified claudin-2 as a functional mediator of breast cancer liver metastasis. We now confirm that claudin-2 levels are elevated in liver metastases, but not in skin metastases, compared to levels in their matched primary tumors in patients with breast cancer. Moreover, claudin-2 is specifically expressed in liver-metastatic breast cancer cells compared to populations derived from bone or lung metastases. The increased liver tropism exhibited by claudin-2-expressing breast cancer cells requires claudin-2-mediated interactions between breast cancer cells and primary hepatocytes. Furthermore, the reduction of the claudin-2 expression level, either in cancer cells or in primary hepatocytes, diminishes these heterotypic cell-cell interactions. Finally, we demonstrate that the first claudin-2 extracellular loop is essential for mediating tumor cell-hepatocyte interactions and the ability of breast cancer cells to form liver metastases in vivo. Thus, during breast cancer liver metastasis, claudin-2 shifts from acting within tight-junctional complexes to functioning as an adhesion molecule between breast cancer cells and hepatocytes.