Metastatic Organotropism Research Articles

Determinants of Organotropic Metastasis

The spread of cancer from a primary tumor to distant organ sites is the most devastating aspect of malignancy. Dissemination to specific organs depends upon blood flow patterns and characteristics of the distant organ environment, such as the vascular architecture, stromal cell content, and the biochemical milieu of growth factors, signaling molecules, and metabolic substrates, which can be permissive or antagonistic to metastatic colonization. Metastatic tumor cells possess intrinsic cellular properties selected for adaptation to specific organ environments, where they co-opt growth and survival signals, undergo metabolic reprogramming, and subvert resident stromal cell activities to promote extravasation, immune evasion, angiogenesis, and overt metastatic growth. Recent work and new experimental models of metastatic organotropism are uncovering crucial details of how malignant cells metastasize to specific tissues, revealing key mediators that prepare metastatic niches in specific organs and identifying new targets that offer attractive options for therapeutic intervention.

Metastatic Organotropism: An Intrinsic Property of Breast Cancer Molecular Subtypes.

It has long been known that some cancers have the propensity to metastasize to certain organs thus creating a nonrandom distribution of sites for distant relapse, a phenomenon known as "metastatic organotropism." Some of these examples include ovary primary to abdominal cavity, prostate primary to bone, and pancreas primary to liver. In contrast, other tumor types, such as mammary and renal cell carcinoma, can relapse in multiple organs although approximately half of advanced breast cancers metastasize to bone. On the other hand gene expression profiling studies have identified various breast cancer classes with prognostic significance. Recent studies have revealed that breast cancer subtypes differ not only in primary tumor characteristics but also in their metastatic behavior. In particular, the luminal tumors are remarkable for their significant bone-seeking phenotype; the HER2 subtype demonstrates a significant liver-homing characteristic; whereas so-called triple-negative breast cancers predispose to lung metastases. These findings suggest that this knowledge could potentially be utilized in the development of effective disease surveillance strategies in the pursuit of precision medicine, thus necessitating further investigation.

The Multiple Roles of Exosomes in Metastasis.

Exosomes are important contributors to cell-cell communication and their role as diagnostic markers for cancer and the pathogenesis for cancer is under intensive investigation. Here, we focus on their role in metastasis-related processes. We discuss their impact regarding promotion of invasion and migration of tumor cells, conditioning of lymph nodes, generation of premetastatic niches and organotropism of metastasis. Furthermore, we highlight interactions of exosomes with bone marrow and stromal components such as fibroblasts, endothelial cells, myeloid- and other immune-related cells in the context of metastases. For all processes as described above, we outline molecular and cellular components for therapeutic intervention with metastatic processes.

Tumour exosome integrins determine organotropic metastasis.

Ever since Stephen Paget’s 1889 hypothesis, metastatic organotropism has remained one of cancer’s greatest mysteries. Here we demonstrate that exosomes from mouse and human lung-, liver- and brain-tropic tumour cells fuse preferentially with resident cells at their predicted destination, namely lung fibroblasts and epithelial cells, liver Kupffer cells and brain endothelial cells. We show that tumour-derived exosomes uptaken by organ-specific cells prepare the pre-metastatic niche. Treatment with exosomes from lung-tropic models redirected the metastasis of bone-tropic tumour cells. Exosome proteomics revealed distinct integrin expression patterns, in which the exosomal integrins α6β4 and α6β1 were associated with lung metastasis, while exosomal integrin αvβ5 was linked to liver metastasis. Targeting the integrins α6β4 and αvβ5 decreased exosome uptake, as well as lung and liver metastasis, respectively. We demonstrate that exosome integrin uptake by resident cells activates Src phosphorylation and pro-inflammatory S100 gene expression. Finally, our clinical data indicate that exosomal integrins could be used to predict organ-specific metastasis.

MP37-14 RNA INTERFERENCE-MEDIATED KNOCKDOWN OF CHD1 IN HUMAN PROSTATE XENOGRAFT TUMORS ALTERS TUMOR GROWTH AND METASTATIC BEHAVIOR

You have accessJournal of UrologyProstate Cancer: Basic Research I1 Apr 2015MP37-14 RNA INTERFERENCE-MEDIATED KNOCKDOWN OF CHD1 IN HUMAN PROSTATE XENOGRAFT TUMORS ALTERS TUMOR GROWTH AND METASTATIC BEHAVIOR Su Jung Oh, Derya Tilki, Hüseyin Sirma, Ronald Simon, and Tobias Lange Su Jung OhSu Jung Oh More articles by this author , Derya TilkiDerya Tilki More articles by this author , Hüseyin SirmaHüseyin Sirma More articles by this author , Ronald SimonRonald Simon More articles by this author , and Tobias LangeTobias Lange More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1277AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Chromodomain helicase DNA-binding protein 1 (CHD1) is a tumor suppressor which is frequently homozygously deleted genes in prostate cancer (PCa). It still remains unclear whether this molecule is involved in metastatic behavior of PCa. To elucidate the role of CHD1 in tumor metastatic dissemination, we analyzed the tumorigenic and metastatic potential of PCa cells after RNAi-mediated knockdown (KD) of CHD1. METHODS CHD1 was stably depleted in PC-3 cells by lentiviral transduction of short hairpin RNA (shRNA) with puromycin resistance (PC-3-shCHD1). Control cells had an empty vector (PC-3-shNeg). The KD of CHD1 was confirmed by western blot. In vivo, PC-3-shCHD1 and -shNeg were subcutaneously xenografted into immunodeficient pfp−/−/rag2−/− mice. After 6 weeks, mice were euthanized. Both primary tumors and right lungs were processed for histopathological analysis. Quantification of spontaneous lung metastases was performed by direct microscopic visualization and counting. DNA from blood, left lungs and bone marrow were isolated for quantification of DTC and CTC by Alu-PCR. Effects of CHD1 depletion on cell adhesion were analyzed by static and dynamic flow adhesion assays. RESULTS KD of CHD1 by shRNA resulted in down-regulation of CHD1 protein levels by about 50%. In vivo, xenograft primary tumors were significantly larger in the CHD1-depleted group accompanied by a reduced number of DTC in the bone marrow compared to the control. Strikingly, the number of DTC in the lungs was increased. Spontaneous lung metastases consisted of several cells per metastasis after CHD1-depletion, whereas control cells predominantly formed single cell lung metastases as known from parental PC-3 in this model. Moreover, CHD1-depletion significantly increased the number of adhesive events of PC-3 under dynamic conditions. Static adhesive interactions and CTC-levels did not change upon CHD1-depletion. CONCLUSIONS KD of the tumor suppressor CHD1 increases tumorigenicity and drastically changes metastatic organotropism in a spontaneous metastasis xenograft model of human PCa. In particular, CHD1-depletion specifically promoted spontaneous dissemination into the lung, whereas dissemination into the bone marrow was abrogated. This might be reflected by the increased adhesive properties of CHD1-depleted PC-3 on pulmonary endothelium. We moreover hypothesize that CHD1 might suppress the switch of ‘dormant’ single cell DTC to proliferating metastatic colonies in the lung and indicate a possible novel role of altered CHD1 in metastatic behavior of PCa. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e443 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Su Jung Oh More articles by this author Derya Tilki More articles by this author Hüseyin Sirma More articles by this author Ronald Simon More articles by this author Tobias Lange More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Abstract BS03-1: Tumor-derived exosomes promote pre-metastatic niche formation and organotropism

Abstract Metastasis is the most deadly aspect of cancer due to a lack of appropriate therapies. Tumor-secreted factors have been recently recognized to be one of the main culprits for metastatic progression. Tumor-secreted factors such as VEGF-A, PlGF, TGFb, TNF-a, and LOX have been shown to play active roles in the recruitment of bone marrow (BM)-derived cells to the primary tumor microenvironment and pre-metastatic niches. We have found that tumor-derived exosomes are abundantly secreted into the circulation in highly metastatic murine models and in patients with stage IV metastatic disease. Tumor-derived exosomes induce vascular leakiness, and hypoxic and pro-inflammatory changes at pre-metastatic sites. Moreover, tumor-derived exosomes preferentially fuse and “educate” BM-derived progenitor cells to a pro-vasculogenic phenotype characterized by upregulation of Tie-2, VEGF-A, VEGFR2, TSP1 and ADAM10. We found that B16-F10 melanoma-derived exosomes help establish pre-metastatic niches, including the recruitment of “educated” BM cells, in specific organs destined to be involved in future metastasis whereas LLC lung cancer-derived exosomes predominant in the lung as the main organ of metastasis. These results suggest that tumor-derived exosomes may have a role in metastatic organotropism, whereby cancer metastasizes to specific organs, as proposed by Stephen Paget's ‘seed and soil’ hypothesis more than a 100 years ago. We believe that the identification of exosomes proteins, with their prognostic and therapeutic potential, may also partially explain the specific receptor-ligand binding of exosomes to a pre-metastatic niche defining an organotropic site for future metastasis. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr BS03-1.

A nude mouse model of hepatocellular carcinoma single cell-derived organ site-specific metastasis

To establish a single cell-derived organ site-specific metastatic model of human hepatocellular carcinoma (HCC) in the nude mouse. Using the limited dilution method, HCCLM3-R-LM1 and HCCLM3-R-LnM1 cell lines were used to generate eight (LM1-S2, -S3, -S4, -S5, -S11, -S15, -S21, and -S23) and five (LnM1-S7, -S11, -S13, -S17, and -S20) single cell-derived monoclonal cell lines, respectively. The monoclonal cell lines were seeded into 4-week-old nude mice, and three weeks later the resultant subcutaneous tumor tissues were orthotopically transplanted into the livers of nude mice. At six weeks after implantation, lung and lymph node were extracted for analysis of the metastatic foci fluorescence area and pathology to assess the number of metastatic foci. Among the 13 mice implanted with the established monoclonal cell lines, six grew subcutaneous tumors. When orthotopically transplanted, the six tumors showed remarkably different metastatic potential and organ site-specific tropism. The fluorescence areas of lung metastatic foci were: LM1-S3, 80 923+/-10 162; LM1-S4, 1506 000+/-297 064; LM1-S5, 36 140+/-8 210; and LM1-S11, 508 448+/-134 272 (P less than 0.01); no lymph node metastases were found for these lines. For LnM1-S11, the fluorescence areas of lung and lymph node metastatic foci were 435 062+/-206 620 and 1 254 000+/-225 171, respectively. We successfully established several monoclonal cell lines and nude mouse models of HCC with different metastatic potential and organ tropism. Among them, LM1-S3, LM1-S4, LM1-S5, and LM1-S11 have metastasis organotropism to lung. The LnM1-S11 line exhibits dual metastasis organotropism to lung and lymph node. These monoclonal cell lines and nude mouse models may represent useful tools for study of HCC metastasis organotropism.

NHERF1 acts as a molecular switch to program metastatic behavior and organotropism via its PDZ domains

Metastatic cells are highly plastic for differential expression of tumor phenotype hallmarks and metastatic organotropism. The signaling proteins orchestrating the shift of one cell phenotype and organ pattern to another are little known. Na(+)/H(+) exchanger regulatory factor (NHERF1) is a molecular pathway organizer, PDZ-domain protein that recruits membrane, cytoplasmic, and cytoskeletal signaling proteins into functional complexes. To gain insight into the role of NHERF1 in metastatic progression, we stably transfected a metastatic breast cell line, MDA-MB-231, with an empty vector, with wild-type NHERF1, or with NHERF1 mutated in either the PDZ1- or PDZ2-binding domains to block their binding activities. We observed that NHERF1 differentially regulates the expression of two phenotypic programs through its PDZ domains, and these programs form the mechanistic basis for metastatic organotropism. The PDZ2 domain promotes visceral metastases via increased invadopodia-dependent invasion and anchorage-independent growth, as well as by inhibition of apoptosis, whereas the PDZ1 domain promotes bone metastases by stimulating podosome nucleation, motility, neoangiogenesis, vasculogenic mimicry, and osteoclastogenesis in the absence of increased growth or invasion. Collectively, these findings identify NHERF1 as an important signaling nexus for coordinating cell structure with metastatic behavior and identifies the "mesenchymal-to-vasculogenic" phenotypic transition as an essential step in metastatic progression.

368 The molecular switch NHERF1 induces tumour phenotypic changes associated with distinct metastatic organotropism in breast cancer via its PDZ domains

368 The molecular switch NHERF1 induces tumour phenotypic changes associated with distinct metastatic organotropism in breast cancer via its PDZ domains

Efficient acquisition of dual metastasis organotropism to bone and lung through stable spontaneous fusion between MDA-MB-231 variants

Cell fusion is involved in many critical developmental processes, including zygote formation and organogenesis of placenta, bone, and skeletal muscle. In adult tissues, cell fusion has been shown to play an active role in tissue regeneration and repair, and its frequency of occurrence is significantly increased during chronic inflammation. Fusion between tumor cells and normal cells, or among tumor cells themselves, has also been speculated to contribute to tumor initiation, as well as phenotypic evolution during cancer progression and metastasis. Here, we show that dual metastasis organotropisms can be acquired in the same cell through in vitro or in vivo spontaneous fusion between bone- and lung-tropic sublines of the MDA-MB-231 human breast cancer cell line. The synkaryonic hybrids assimilate organ-specific metastasis gene signatures from both parental cells and are genetically and phenotypically stable. Our study suggests cell fusion as an efficient means of phenotypic evolution during tumor progression and additionally demonstrates the compatibility of different metastasis organotropisms.

Hepatic complications of breast cancer

Hepatic disease associated with breast cancer is common and can result from metastatic spread of the tumour to the liver, or can be caused by systemic treatment with chemotherapeutic or antiendocrine agents. Metastatic disease to the liver can present clinically and pathologically in various ways. Little is known as to why breast cancer can sometimes present as liver dominant disease or with liver involvement as a late event in the disease course. However, there are many postulations involving metastasis organotropism, which might offer future insight. The mainstay of treatment for hepatic metastases continues to be systemic therapy, but several locoregional adjunct therapies exist. Despite these therapies, liver metastasis from breast cancer is associated with a poor prognosis. Ongoing research of the mechanisms and tropism of liver metastasis from breast cancer will hopefully result in improved targeted therapies to reduce their incidence and improve outcomes when they arise.

Organotropism of Breast Cancer Metastasis

Breast cancer causes mortality by metastasizing to a variety of vital organs, such as bone, lung, brain and liver. Effective therapeutic intervention of this deadly process relies on a better mechanistic understanding of metastasis organotropism. Recent studies have confirmed earlier speculations that metastasis is a non-random process and is dependent on intricate tumor-stroma interactions at the target organ. Both the intrinsic properties of breast cancer cells and the host organ microenvironment are important in determining the efficiency of organ-specific metastasis. Advances in animal modeling, in vivo imaging and functional genomics have accelerated the discovery of important molecular mediators of organ-specific metastasis. A conceptual framework of breast cancer organotropism is emerging and will be instrumental in guiding future efforts in this exciting research field.