miRNA-30 family members inhibit breast cancer invasion, osteomimicry, and bone destruction by directly targeting multiple bone metastasis–associated genes

miRNAs are master regulators of gene expression that play key roles in cancer metastasis. During bone metastasis, metastatic tumor cells must rewire their biology and express genes that are normally expressed by bone cells (a process called osteomimicry), which endow tumor cells with full competence for outgrowth in the bone marrow. Here, we establish miR-30 family members miR-30a, miR-30b, miR-30c, miR-30d, and miR-30e as suppressors of breast cancer bone metastasis that regulate multiple pathways, including osteomimicry. Low expression of miR-30 in primary tumors from patients with breast cancer were associated with poor relapse-free survival. In addition, estrogen receptor (ER)-negative/progesterone receptor (PR)-negative breast cancer cells expressed lower miR-30 levels than their ER/PR-positive counterparts. Overexpression of miR-30 in ER/PR-negative breast cancer cells resulted in the reduction of bone metastasis burden in vivo. In vitro, miR-30 did not affect tumor cell proliferation, but did inhibit tumor cell invasion. Furthermore, overexpression of miR-30 restored bone homeostasis by reversing the effects of tumor cell–conditioned medium on osteoclastogenesis and osteoblastogenesis. A number of genes associated with osteoclastogenesis stimulation (IL8, IL11), osteoblastogenesis inhibition (DKK-1), tumor cell osteomimicry (RUNX2, CDH11), and invasiveness (CTGF, ITGA5, ITGB3) were identified as targets for repression by miR-30. Among these genes, silencing CDH11 or ITGA5 in ER-/PR-negative breast cancer cells recapitulated inhibitory effects of miR-30 on skeletal tumor burden in vivo. Overall, our findings provide evidence that miR-30 family members employ multiple mechanisms to impede breast cancer bone metastasis and may represent attractive targets for therapeutic intervention. Significance: These findings suggest miR-30 family members may serve as an effective means to therapeutically attenuate metastasis in triple-negative breast cancer

The role of Dysregulated Microrna in Ovarian Cancer

Ovarian cancer is the most lethal gynaecological malignancy and the sixth most common cause of cancer death in Australian women. Epithelial ovarian cancer accounts for 90% of ovarian cancers, of which, serous epithelial ovarian cancer is the most common and aggressive histological subtype. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that negatively regulate genes involved in cancer. Genomic instability is a hallmark of ovarian cancer which may be exacerbated by DNA hypomethylation. The role of aberrant methylation and copy number variation (CNV) on miRNA dysregulation was assessed by qPCR methylation arrays and integrative analysis of cytogenetic arrays, miRNA expression and gene expression profiles. Several miRNAs identified to be adjacent to CpG islands aberrantly methylated or located in regions of CNV. Of these, the mir-23a/mir-24-2/mir-27a cluster and mir-425 were identified to be in regions of CNV and were predicted to target oncogenic receptor tyrosine kinases AXL and MET. Furthermore, one of the unmet needs for ovarian cancer patient survival is reliable detection. Current diagnostic tests for ovarian cancer may be improved by expansion of biomarker panels such as circulating miRNAs. Assessment of miRNA expression profiles identified the miR-200 family to be over-expressed in ovarian cancer patient serum

Cancer Cell Colonisation in the Bone Microenvironment

Bone metastases are a common complication of epithelial cancers, of which breast, prostate and lung carcinomas are the most common. The establishment of cancer cells to distant sites such as the bone microenvironment requires multiple steps. Tumour cells can acquire properties to allow epithelial-to-mesenchymal transition, extravasation and migration. Within the bone metastatic niche, disseminated tumour cells may enter a dormancy stage or proliferate to adapt and survive, interacting with bone cells such as hematopoietic stem cells, osteoblasts and osteoclasts. Cross-talk with the bone may alter tumour cell properties and, conversely, tumour cells may also acquire characteristics of the surrounding microenvironment, in a process known as osteomimicry. Alternatively, these cells may also express osteomimetic genes that allow cell survival or favour seeding to the bone marrow. The seeding of tumour cells in the bone disrupts bone-forming and bone-resorbing activities, which can lead to macrometastasis in bone. At present, bone macrometastases are incurable with only palliative treatment available. A better understanding of how these processes influence the early onset of bone metastasis may give insight into potential therapies. This review will focus on the early steps of bone colonisation, once disseminated tumour cells enter the bone marrow

Cancer Cell Colonisation in the Bone Microenvironment

Bone metastases are a common complication of epithelial cancers, of which breast, prostate and lung carcinomas are the most common. The establishment of cancer cells to distant sites such as the bone microenvironment requires multiple steps. Tumour cells can acquire properties to allow epithelial-to-mesenchymal transition, extravasation and migration. Within the bone metastatic niche, disseminated tumour cells may enter a dormancy stage or proliferate to adapt and survive, interacting with bone cells such as hematopoietic stem cells, osteoblasts and osteoclasts. Cross-talk with the bone may alter tumour cell properties and, conversely, tumour cells may also acquire characteristics of the surrounding microenvironment, in a process known as osteomimicry. Alternatively, these cells may also express osteomimetic genes that allow cell survival or favour seeding to the bone marrow. The seeding of tumour cells in the bone disrupts bone-forming and bone-resorbing activities, which can lead to macrometastasis in bone. At present, bone macrometastases are incurable with only palliative treatment available. A better understanding of how these processes influence the early onset of bone metastasis may give insight into potential therapies. This review will focus on the early steps of bone colonisation, once disseminated tumour cells enter the bone marrow

Lysyl oxidase is a strong determinant of tumor cell colonization in bone. Short Title: LOX triggers tumor cell colonization in bone

International audienceLysyl oxidase (LOX) is a secreted copper-dependent amine oxidase whose primary function is to drive collagen crosslinking and extracellular matrix stiffness. LOX in colorectal cancer (CRC) synergizes with hypoxia-inducible factor-1 (HIF-1 to promote tumor progression. Here we investigated whether LOX/HIF1 endows CRC cells with full competence for aggressive colonization in bone. We show that a high LOX expression in primary tumors from CRC patients was associated with poor clinical outcome, irrespective of HIF-1. Additionally, LOX was expressed by tumor cells in the bone marrow from CRC patients with bone metastases. In vivo experimental studies show that LOX overexpression in CRC cells or systemic delivery of the conditioned medium from LOX-overexpressing CRC cells promoted tumor cell dissemination in the bone marrow and enhanced osteolytic lesion formation, irrespective of HIF-1. Conversely, silencing or pharmacological inhibition of LOX activity blocked dissemination of CRC cells in the bone marrow and tumor-driven osteolytic lesion formation. In vitro, tumor-secreted LOX supported the attachment and survival of CRC cells to and in the bone matrix, and inhibited osteoblast differentiation. LOX overexpression in CRC cells also induced a robust production of IL-6. In turn, both LOX and IL-6 were acting in concert to promote RANKL-dependent osteoclast differentiation, thereby creating an imbalance between bone resorption and bone formation. Collectively, our findings show that LOX supports CRC cell dissemination in the bone marrow and they reveal a novel mechanism through which LOX-driven IL-6 production by CRC cells impairs bone homeostasis

Lysyl oxidase is a strong determinant of tumor cell colonization in bone. Short Title: LOX triggers tumor cell colonization in bone

International audienceLysyl oxidase (LOX) is a secreted copper-dependent amine oxidase whose primary function is to drive collagen crosslinking and extracellular matrix stiffness. LOX in colorectal cancer (CRC) synergizes with hypoxia-inducible factor-1 (HIF-1 to promote tumor progression. Here we investigated whether LOX/HIF1 endows CRC cells with full competence for aggressive colonization in bone. We show that a high LOX expression in primary tumors from CRC patients was associated with poor clinical outcome, irrespective of HIF-1. Additionally, LOX was expressed by tumor cells in the bone marrow from CRC patients with bone metastases. In vivo experimental studies show that LOX overexpression in CRC cells or systemic delivery of the conditioned medium from LOX-overexpressing CRC cells promoted tumor cell dissemination in the bone marrow and enhanced osteolytic lesion formation, irrespective of HIF-1. Conversely, silencing or pharmacological inhibition of LOX activity blocked dissemination of CRC cells in the bone marrow and tumor-driven osteolytic lesion formation. In vitro, tumor-secreted LOX supported the attachment and survival of CRC cells to and in the bone matrix, and inhibited osteoblast differentiation. LOX overexpression in CRC cells also induced a robust production of IL-6. In turn, both LOX and IL-6 were acting in concert to promote RANKL-dependent osteoclast differentiation, thereby creating an imbalance between bone resorption and bone formation. Collectively, our findings show that LOX supports CRC cell dissemination in the bone marrow and they reveal a novel mechanism through which LOX-driven IL-6 production by CRC cells impairs bone homeostasis

ERRα expression in bone metastases leads to an exacerbated anti-tumor immune response

International audienceBone is the most common metastatic site for breast cancer. Although the estrogen-related receptor alpha (ERRα) has been implicated in breast cancer cell dissemination to the bone from the primary tumor, its role after tumor cell anchorage in the bone microenvironment remains elusive. Here, we reveal that ERRα inhibits the progression of bone metastases of breast cancer cells by increasing the immune activity of the bone microenvironment. Overexpression of ERRα in breast cancer bone metastases induced expression of chemokines CCL17 and CCL20 and repressed production of TGFβ3. Subsequently, CD8(+) T lymphocytes recruited to bone metastases escaped TGFβ signaling control and were endowed with exacerbated cytotoxic features, resulting in significant reduction in metastases. The clinical relevance of our findings in mice was confirmed in over 240 patients with breast cancer. Thus, this study reveals that ERRα regulates immune properties in the bone microenvironment that contributes to decreasing metastatic growth. SIGNIFICANCE: This study places ERRα at the interplay between the immune response and bone metastases of breast cancer, highlighting a potential target for intervention in advanced disease