Metastatic breast cancer cells overexpress and secrete miR-218 to regulate type I collagen deposition by osteoblasts

A novel interplay between PRC2 and miR-3189 regulates epithelial-mesenchymal transition (EMT) via modulating COL6A2 in glioblastoma

Recent studies have shed light on disrupted collagen signaling in Gliomas, yet the regulatory landscape remains largely unexplored. This study enquired into the role of polycomb repressive complex-2 (PRC2)-mediated H3K27me3 modification, a key epigenetic factor in glioma. Using in-house data, we identified miRNAs downregulated in glioblastoma (GBM) with the potential to regulate Collagen VI family genes. Notably, miR-3189 emerged as a prime PRC2 target. Its expression was significantly downregulated in Indian GBM patients as well as other glioma cohorts. Mechanistic insights, involving Luciferase assays, mutagenesis, and Western blot analysis, confirmed direct targeting of Collagen VI member COL6A2 by miR-3189-3p. Functional assays demonstrated that miR-3189-3p restrained GBM malignancy by inhibiting proliferation, migration, and epithelial-mesenchymal transition (EMT). Conversely, COL6A2 overexpressed in GBM patients, countered miR-3189, and promoted the malignant phenotype. Gene set enrichment analysis highlighted EMT enrichment in GBM patients with elevated COL6A2 expression, carrying prognostic implications. This study uncovers intricate interactions between two epigenetic regulators-H3K27me3 and miR-3189-working synergistically to modulate Collagen VI gene; thus, influencing the malignancy of GBM. Targeting this H3K27me3|miR-3189-3p|COL6A2 axis presents a potential therapeutic avenue against GBM.

Breast cancer cell-secreted miR-199b-5p hijacks neurometabolic coupling to promote brain metastasis

Breast cancer metastasis to the brain is a clinical challenge rising in prevalence. However, the underlying mechanisms, especially how cancer cells adapt a distant brain niche to facilitate colonization, remain poorly understood. A unique metabolic feature of the brain is the coupling between neurons and astrocytes through glutamate, glutamine, and lactate. Here we show that extracellular vesicles from breast cancer cells with a high potential to develop brain metastases carry high levels of miR-199b-5p, which shows higher levels in the blood of breast cancer patients with brain metastases comparing to those with metastatic cancer in other organs. miR-199b-5p targets solute carrier transporters (SLC1A2/EAAT2 in astrocytes and SLC38A2/SNAT2 and SLC16A7/MCT2 in neurons) to hijack the neuron-astrocyte metabolic coupling, leading to extracellular retention of these metabolites and promoting cancer cell growth. Our findings reveal a mechanism through which cancer cells of a non-brain origin reprogram neural metabolism to fuel brain metastases.

DDR1-targeted therapies: current limitations and future potential

Discoidin domain receptor (DDR)-1 has a crucial role in regulating vital processes, including cell differentiation, proliferation, adhesion, migration, invasion, and matrix remodeling. Overexpression or activation of DDR1 in various pathological scenarios makes it a potential therapeutic target for the treatment of cancer, fibrosis, atherosclerosis, and neuropsychiatric, psychiatric, and neurodegenerative disorders. In this review, we summarize current therapeutic approaches targeting DDR1 from a medicinal chemistry perspective. Furthermore, we analyze factors other than issues of low selectivity and risk of resistance, contributing to the infrequent success of DDR1 inhibitors. The complex interplay between DDR1 and the extracellular matrix (ECM) necessitates additional validation, given that DDR1 might exhibit complex and synergistic interactions with other signaling molecules during ECM regulation. The mechanisms involved in DDR1 regulation in cancer and inflammation-related diseases also remain unknown.

Exosomal microRNAs in breast cancer: towards theranostic applications

Breast cancer is one of the top two reproductive cancers responsible for high rates of morbidity and mortality among women globally. Despite the advancements in the treatment of breast cancer, its early diagnosis remains a challenge. Recent evidence indicates that despite the adroit use of numerous strategies to facilitate rapid and precision-oriented screening of breast cancer at the community level through the use of mammograms, Fine-needle aspiration cytology (FNAC) and biomarker tracking, no strategy has been unequivocally accepted as a gold standard for facilitating rapid screening for disease. This necessitates the need to identify novel strategies for the detection and triage of breast cancer lesions at higher rates of specificity, and sensitivity, whilst taking into account the epidemiologic and social-demographic features of the patients. Recent shreds of evidence indicate that exosomes could be a robust source of biomaterial for the rapid screening of breast cancer due to their high stability and their presence in body fluids. Increasing evidence indicates that the Exosomal microRNAs- play a significant role in modifying the tumour microenvironment of breast cancers, thereby potentially aiding in the proliferation, invasion and metastasis of breast cancer. In this review, we summarize the role of ExomiRs in the tumour microenvironment in breast cancer. These ExomiRs can also be used as candidate biomarkers for facilitating rapid screening and triaging of breast cancer patients for clinical intervention.

Collagen 1A1 (COL1A1) and Collagen11A1(COL11A1) as diagnostic biomarkers in Breast, colorectal and gastric cancers

PURPOSE

Collagen family genes (CFGs) play a significant role in the pathogenesis of cancers. This study aimed to evaluate changes in the expression levels (Els) of CFGs related to epithelial-mesenchymal transition (EMT) and metastasis in gastric (GC), breast (BC), and colorectal (CRC) cancers to introduce these genes as potential diagnostic biomarkers for these three types of cancer.

METHODS

The Cancer Genome Atlas (TCGA) examined ELS changes in CFGs associated with EMT and metastasis to determine their diagnostic value for GC, BC, and CRC. InteractiVenn was used to find genes shared by these three cancers. The biomarker role of CFGs was determined using the receiver operating characteristic (ROC) analysis. GC, BC, and CRC samples were analyzed using the RT-qPCR method to verify the bioinformatics results and evaluate the EL of the selected genes as biomarkers for these cancers.

RESULTS

The in-silico results showed a significant increase in the EL of several CFGs involved in EMT and metastasis in GC, BC, and CRC samples compared to healthy samples. Six common genes (COL11A1, COL12A1, COL1A1, COL1A2, COL5A1, and COL5A2) showed significantly increased in these three cancers, therebysupporting their oncogenic role. Furthermore, the biomarker-related analyses indicated that COL11A1 and COL1A1 were common diagnostic biomarkers for the three cancers. The RT-qPCR method confirmed that the ELs of COL11A1 and COL1A1 in the GC, BC, and CRC samples increased significantly compared to the adjacent normal samples.

CONCLUSION

CFGs in EMT and metastasis of GC, BC, and CRC are strong common diagnostic biomarkers for these cancers.

Mesenchymal stem cell-derived exosomes enriched with miR-218 reduce the epithelial-mesenchymal transition and angiogenesis in triple-negative breast cancer cells

BACKGROUND

The epithelial-mesenchymal transition (EMT) and angiogenesis are morphogenetic processes implicated in tumor invasion and metastasis. It is found that the aberrant expression of microRNAs (miRNAs) contributes to these processes. Exosomes are considered potential natural vehicles for miRNA delivery in cancer therapy. miR-218 is one of the tumor suppressor miRNAs and its downregulation is associated with EMT and angiogenesis. We aimed to use adipose mesenchymal stem cells-derived exosomes (ADMSC-exosomes) for miR-218 delivery to breast cancer cells and evaluate miR-218 tumor-suppressing properties in vitro.

METHODS

Exosomes were isolated from conditioned media of ADMSCs. miR-218 was loaded to exosomes using electroporation. mRNA expression of target genes (Runx2 and Rictor) in MDA-MB-231 breast cancer cells was evaluated by qPCR. To explore the effects of miR-218 containing exosomes on breast cancer cells, viability, apoptosis, and Boyden chamber assays were performed. The angiogenic capacity of MDA-MB-231 cells after treatment with miR-218 containing exosomes was assessed by in vitro tube formation assay.

RESULTS

miR-218 mimic was efficiently loaded to ADMSC-exosomes and delivered to MDA-MB-231 cells. Exposure to miR-218 containing exosomes significantly decreased miR-218 target genes (Runx2 and Rictor) in MDA-MB-231 cells. They increased the expression of epithelial marker (CDH1) and reduced mesenchymal marker (CDH2). miR-218 restoration using miR-218 containing exosomes reduced viability, motility, invasion, and angiogenic capacity of breast cancer cells.

CONCLUSIONS

These findings suggest that ADMSC-exosomes can efficiently restore miR-218 levels in breast cancer cells and miR-218 can prevent breast cancer progression with simultaneous targeting of angiogenesis and EMT.

MicroRNAs mediated interaction of tumor microenvironment cells with breast cancer cells during bone metastasis

Breast cancer (BC) bone metastasis is primarily osteolytic and has limited therapeutic options. Metastasized BC cells prime the secondary environment in bone by forming a tumor niche, which favors their homing and colonization. The tumor microenvironment (TME) is primarily generated by the cancer cells. Bone TME is an intricate network of multiple cells, including altered bone, tumor, stromal, and immune cells. Recent findings highlight the significance of small non-coding microRNAs (miRNAs) in influencing TME during tumor metastasis. MiRNAs from TME-resident cells facilitate the interaction between the tumor and its microenvironment, thereby regulating the biological processes of tumors. These miRNAs can serve as oncogenes or tumor suppressors. Hence, both miRNA inhibitors and mimics are extensively utilized in pre-clinical trials for modulating the phenotypes of tumor cells and associated stromal cells. This review briefly summarizes the recent developments on the functional role of miRNAs secreted directly or indirectly from the TME-resident cells in facilitating tumor growth, progression, and metastasis. This information would be beneficial in developing novel targeted therapies for BC.

The role of non-coding RNAs in extracellular vesicles in breast cancer and their diagnostic implications

Breast Cancer (BC) is the most common form of cancer worldwide, responsible for 25% of cancers in women. Whilst treatment is effective and often curative in early BC, metastatic disease is incurable, highlighting the need for early detection. Currently, early detection relies on invasive procedures, however recent studies have shown extracellular vesicles (EVs) obtained from liquid biopsies may have clinical utility. EVs transport diverse bioactive cargos throughout the body, play major roles in intercellular communication and, importantly, mirror their cell of origin. In cancer cells, EVs alter the behaviour of the tumour microenvironment (TME), forming a bridge of communication between cancerous and non-cancerous cells to alter all aspects of cancer progression, including the formation of a pre-metastatic niche. Through gene regulatory frameworks, non-coding RNAs (ncRNAs) modulate vital molecular and cellular processes and can act as both tumour suppressors and oncogenic drivers in various cancer types. EVs transport and protect ncRNAs, facilitating their use clinically as liquid biopsies for early BC detection. This review summarises current research surrounding ncRNAs and EVs within BC, focusing on their roles in cancer progression through bi-directional communication with the microenvironment and their diagnostic implications. The role of EV ncRNAs in breast cancer. A representation of the different EV ncRNAs involved in tumourigenic processes in breast cancer. Pro-tumourigenic ncRNAs displayed in green and ncRNAs which inhibit oncogenic processes are shown in red.

Recent advances in novel miRNA mediated approaches for targeting breast cancer

Breast cancer (BC) is considered one of the most frequent cancers among woman worldwide. While conventional therapy has been successful in treating many cases of breast cancer, drug resistance, heterogenicity, tumour features and recurrence, invasion, metastasis and the presence of breast cancer stem cells can hinder the effect of treatments, and can reduce the quality of life of patients. MicroRNAs (miRNAs) are short non-coding RNA molecules that play a crucial role in the development and progression of breast cancer. Several studies have reported that aberrant expression of specific miRNAs is associated with the pathogenesis of breast cancer. However, miRNAs are emerging as potential biomarkers and therapeutic targets for breast cancer. Understanding their role in breast cancer biology could help develop more effective treatments for this disease. The present study discusses the biogenesis and function of miRNAs, as well as miRNA therapy approaches for targeting and treating breast cancer cells.

Extracellular Vesicles-A Source of RNA Biomarkers for the Detection of Breast Cancer in Liquid Biopsies

Over the past decade, extracellular vesicles (EVs) have emerged as a promising source of cancer-derived RNAs for liquid biopsies. However, blood contains a pool of heterogeneous EVs released by a variety of cell types, making the identification of cancer RNA biomarkers challenging. Here, we performed deep sequencing of plasma EV RNA cargo in 32 patients with locally advanced breast cancer (BC) at diagnosis and 7 days after breast surgery and in 30 cancer-free healthy controls (HCs). To identify BC-derived RNA biomarkers, we searched for RNAs that had higher levels in BC EVs at the time of diagnosis compared with HCs and decreased after surgery. Data analysis showed that the fractions of miRNAs, snRNAs, snoRNAs, and tRFs were increased, but the fraction of lncRNAs was decreased in BC EVs as compared to HCs. BC-derived biomarker candidates were identified across various RNA biotypes. Considered individually, they had very high specificity but moderate sensitivity for the detection of BC, whereas a biomarker model composed of eight RNAs: SNORD3H, SNORD1C, SNORA74D, miR-224-5p, piR-32949, lnc-IFT-122-2, lnc-C9orf50-4, and lnc-FAM122C-3 was able to distinguish BC from HC EVs with an AUC of 0.902 (95% CI = 0.872-0.931, p = 3.4 × 10-9) in leave-one-out cross-validation. Furthermore, a number of RNA biomarkers were correlated with the ER and HER2 expression and additional biomarker models were created to predict hormone receptor and HER2 status. Overall, this study demonstrated that the RNA composition of plasma EVs is altered in BC patients and that they contain cancer-derived RNA biomarkers that can be used for BC detection and monitoring using liquid biopsies.

Extracellular vesicles in the treatment and diagnosis of breast cancer: a status update

Breast cancer is one of the leading causes of cancer-related death in women. Currently, the treatment of breast cancer is limited by the lack of effectively targeted therapy and patients often suffer from higher severity, metastasis, and resistance. Extracellular vesicles (EVs) consist of lipid bilayers that encapsulate a complex cargo, including proteins, nucleic acids, and metabolites. These bioactive cargoes have been found to play crucial roles in breast cancer initiation and progression. Moreover, EV cargoes play pivotal roles in converting mammary cells to carcinogenic cells and metastatic foci by extensively inducing proliferation, angiogenesis, pre-metastatic niche formation, migration, and chemoresistance. The present update review mainly discusses EVs cargoes released from breast cancer cells and tumor-derived EVs in the breast cancer microenvironment, focusing on proliferation, metastasis, chemoresistance, and their clinical potential as effective biomarkers.

Extracellular matrix-derived mechanical force governs breast cancer cell stemness and quiescence transition through integrin-DDR signaling

The extracellular matrix (ECM) serves as signals that regulate specific cell states in tumor tissues. Increasing evidence suggests that extracellular biomechanical force signals are critical in tumor progression. In this study, we aimed to explore the influence of ECM-derived biomechanical force on breast cancer cell status. Experiments were conducted using 3D collagen, fibrinogen, and Matrigel matrices to investigate the role of mechanical force in tumor development. Integrin-cytoskeleton-AIRE and DDR-STAT signals were examined using RNA sequencing and western blotting. Data from 1358 patients and 86 clinical specimens were used for ECM signature-prognosis analysis. Our findings revealed that ECM-derived mechanical force regulated tumor stemness and cell quiescence in breast cancer cells. A mechanical force of ~45 Pa derived from the extracellular substrate activated integrin β1/3 receptors, stimulating stem cell signaling pathways through the cytoskeleton/AIRE axis and promoting tumorigenic potential and stem-like phenotypes. However, excessive mechanical force (450 Pa) could drive stem-like cancer cells into a quiescent state, with the removal of mechanical forces leading to vigorous proliferation in quiescent cancer stem cells. Mechanical force facilitated cell cycle arrest to induce quiescence, dependent on DDR2/STAT1/P27 signaling. Therefore, ECM-derived mechanical force governs breast cancer cell status and proliferative characteristics through stiffness alterations. We further established an ECM signature based on the fibrinogen/fibronectin/vitronectin/elastin axis, which efficiently predicts patient prognosis in breast cancer. Our findings highlight the vital role of ECM-derived mechanical force in governing breast cancer cell stemness/quiescence transition and suggest the novel use of ECM signature in predicting the clinical prognosis of breast cancer.

Non-coding RNA's prevalence as biomarkers for prognostic, diagnostic, and clinical utility in breast cancer

Noncoding RNAs (ncRNAs), which make up a significant portion of the mammalian transcriptome and plays crucial regulatory roles in expression of genes and other biological processes, have recently been found. The most extensively researched of the sncRNAs, microRNAs (miRNAs), have been characterized in terms of their synthesis, roles, and significance in the tumor development. Its crucial function in the stem cell regulation, another class of sncRNAs known as aspirRNAs, has attracted attention in cancer research. The investigations have shown that long non-coding RNAs have a crucial role in controlling developmental stages, such as mammary gland development. Additionally, it has been discovered that lncRNA dysregulation precedes the development of several malignancies, including breast cancer. The functions of sncRNAs (including miRNAs and piRNAs) and lncRNAs in the onset and development of the breast cancer are described in this study. Additionally, future perspectives of various ncRNA-based diagnostic, prognostic, and therapeutic approaches also discussed.

Non-Coding RNAs Derived from Extracellular Vesicles Promote Pre-Metastatic Niche Formation and Tumor Distant Metastasis

Metastasis is a critical stage of tumor progression, a crucial challenge of clinical therapy, and a major cause of tumor patient death. Numerous studies have confirmed that distant tumor metastasis is dependent on the formation of pre-metastatic niche (PMN). Recent studies have shown that extracellular vesicles (EVs) play an important role in PMN formation. The non-coding RNAs (ncRNAs) derived from EVs mediate PMN formation and tumor-distant metastasis by promoting an inflammatory environment, inhibiting anti-tumor immune response, inducing angiogenesis and permeability, and by microenvironmental reprogramming. Given the stability and high abundance of ncRNAs carried by EVs in body fluids, they have great potential for application in tumor diagnosis as well as targeted interventions. This review focuses on the mechanism of ncRNAs derived from EVs promoting tumor PMN formation and distant metastasis to provide a theoretical reference for strategies to control tumor metastasis.

Comparison of Characterization in Two-Dimensional and Three-Dimensional Canine Mammary Gland Tumor Cell Models

Background

Canine mammary gland tumors can be used as predictive models for human breast cancer. There are several types of microRNAs common in human breast cancer and canine mammary gland tumors. The functions of microRNAs in canine mammary gland tumors are not well understood.

Methods

We compared the characterization of microRNA expression in two-dimensional and three-dimensional canine mammary gland tumor cell models. We evaluated the differences between two- and three-dimensional cultured canine mammary gland tumor SNP cells by assessing microRNA expression levels, morphology, drug sensitivity, and hypoxia.

Results

The expression of microRNA-210 in the three-dimensional-SNP cells was 10.19 times higher than that in the two-dimensional-SNP cells. The intracellular concentrations of doxorubicin in the two- and three-dimensional-SNP cells were 0.330 ± 0.013 and 0.290 ± 0.048 nM/mg protein, respectively. The IC₅₀ values of doxorubicin for the two- and three-dimensional-SNP cells were 5.2 and 1.6 μM, respectively. Fluorescence of the hypoxia probe, LOX-1, was observed inside the sphere of three-dimensional-SNP cells without echinomycin but not in two-dimensional-SNP cells. The three-dimensional-SNP cells treated with echinomycin showed weak LOX-1 fluorescence.

Conclusion

The present study showed a clear difference in microRNA expression levels in cells cultured in a two-dimensional adherent versus a three-dimensional spheroid model.

Recent advances of small extracellular vesicle biomarkers in breast cancer diagnosis and prognosis

Current clinical tools for breast cancer (BC) diagnosis are insufficient but liquid biopsy of different bodily fluids has recently emerged as a minimally invasive strategy that provides a real-time snapshot of tumour biomarkers for early diagnosis, active surveillance of progression, and post-treatment recurrence. Extracellular vesicles (EVs) are nano-sized membranous structures 50-1000 nm in diameter that are released by cells into biological fluids. EVs contain proteins, nucleic acids, and lipids which play pivotal roles in tumourigenesis and metastasis through cell-to-cell communication. Proteins and miRNAs from small EVs (sEV), which range in size from 50-150 nm, are being investigated as a potential source for novel BC biomarkers using mass spectrometry-based proteomics and next-generation sequencing. This review covers recent developments in sEV isolation and single sEV analysis technologies and summarises the sEV protein and miRNA biomarkers identified for BC diagnosis, prognosis, and chemoresistance. The limitations of current sEV biomarker research are discussed along with future perspective applications.

MicroRNAs: A Link between Mammary Gland Development and Breast Cancer

Breast cancer is among the most common cancers in women, second to skin cancer. Mammary gland development can influence breast cancer development in later life. Processes such as proliferation, invasion, and migration during mammary gland development can often mirror processes found in breast cancer. MicroRNAs (miRNAs), small, non-coding RNAs, can repress post-transcriptional RNA expression and can regulate up to 80% of all genes. Expression of miRNAs play a key role in mammary gland development, and aberrant expression can initiate or promote breast cancer. Here, we review the role of miRNAs in mammary development and breast cancer, and potential parallel roles. A total of 32 miRNAs were found to be expressed in both mammary gland development and breast cancer. These miRNAs are involved in proliferation, metastasis, invasion, and apoptosis in both processes. Some miRNAs were found to have contradictory roles, possibly due to their ability to target many genes at once. Investigation of miRNAs and their role in mammary gland development may inform about their role in breast cancer. In particular, by studying miRNA in development, mechanisms and potential targets for breast cancer treatment may be elucidated.

Tumor-Derived Exosomes and Their Role in Breast Cancer Metastasis

Breast cancer has been the most common cancer in women worldwide, and metastasis is the leading cause of death from breast cancer. Even though the study of breast cancer metastasis has been extensively carried out, the molecular mechanism is still not fully understood, and diagnosis and prognosis need to be improved. Breast cancer metastasis is a complicated process involving multiple physiological changes, and lung, brain, bone and liver are the main metastatic targets. Exosomes are membrane-bound extracellular vesicles that contain secreted cellular constitutes. The biogenesis and functions of exosomes in cancer have been intensively studied, and mounting studies have indicated that exosomes play a crucial role in cancer metastasis. In this review, we summarize recent findings on the role of breast cancer-derived exosomes in metastasis organotropism and discuss the potential promising clinical applications of targeting exosomes as novel strategies for breast cancer diagnosis and therapy.

Breast Cancer-Delivered Exosomal miRNA as Liquid Biopsy Biomarkers for Metastasis Prediction: A Focus on Translational Research with Clinical Applicability

Metastasis represents the most important cause of breast cancer-associated mortality. Even for early diagnosed stages, the risk of metastasis is significantly high and predicts a grim outcome for the patient. Nowadays, efforts are made for identifying blood-based biomarkers that could reliably distinguish patients with highly metastatic cancers in order to ensure a closer follow-up and a more personalized therapeutic method. Exosomes are nano vesicles secreted by cancer cells that can transport miRNAs, proteins, and other molecules and deliver them to recipient cells all over the body. Through this transfer, cancer cells modulate their microenvironment and facilitate the formation of the pre-metastatic niche, leading to sustained progression. Exosomal miRNAs have been extensively studied due to their promising potential as prognosis biomarkers for metastatic breast cancer. In this review, we tried to depict an overview of the existing literature regarding exosomal miRNAs that are already validated as potential biomarkers, and which could be immediately available for the clinic. Moreover, in the last section, we highlighted several miRNAs that have proven their function in preclinical studies and could be considered for clinical validation. Considering the lack of standard methods for evaluating exosomal miRNA, we also discussed the challenges and the technical aspects underlying this issue.

Extracellular vesicles in bone homeostasis: key roles of physiological and pathological conditions

Extracellular vesicles (EVs) are small particles with lipid bilayer membranes that are secreted by all cell types and are widely known as crucial intercellular communication mediators, shuttling biologically active molecules. The bone is a typically preferred site of cancer metastasis due to its unique cellular compositions and dynamics. Bone cell-derived EVs serve as regulators that orchestrate harmonious bone homeostasis. Cancer cells secrete specific EVs in a series of the bone metastatic process to dominate the bone microenvironment. Additionally, cancer cell-related EVs contribute to pre-metastatic niche formation, bone homeostasis disruption, and tumor bone progression and survival. Here, we investigated recent studies on EV-mediated crosstalk in the bone tumor microenvironment. Furthermore, this review aimed to elucidate the EV-based therapeutic perspectives for bone metastasis.

Prognosticating 2-Year Survival Rate of Breast Cancer Patients Through Plasma miRNA-21 and Other Associating Factors

Background

miRNA-21, one of breast cancer (BC) predictive markers, is now gaining cardinal attention from researchers worldwide to evaluate BC patients' survival rate. However, cancer staging, hormonal status, and other BC markers still have to be discussed. We aim to determine the relationship between miRNA-21 and associating factors such as BC staging, other tumor markers, and hormonal status to predict the 2-year survival rate of BC patients.

Methods

We conducted a prospective cohort study on 49 BC patients (26 early stage, 23 advanced stage). Apart from cancer staging, we also examined CEA, Ca15-3, and hormonal status (ER, PR, Her2) and correlated them with miRNA-21 to predict 2-year survival rate. We did bivariate, multivariate, and survival analyses to determine the link between miRNA-21 and those factors to prognosticate on 2-year survival rate.

Results

There are significances between advanced and loco-regional stage (p < 0.001); high and low miRNA-21 (p = 0.002) and CA 15-3 (p = 0.001), and low survival rate in patients with ER/PR-Her2- status (p=0.0015). Cox proportional hazard showed miRNA-21 (Adjusted HR 1.41; 95% CI = 1.205-1.632), cancer stage (Adjusted HR 9.5; 95% CI = 1.378-20.683), and CA15-3 (Adjusted HR 4.64; 95% CI = 1.548-13.931) affected patients' mortality within 2 years.

Conclusion

Low two-year survival rate depends on miRNA-21, cancer stage, CA15-3, and ER/PR-Her2-. Cancer stage is robustly associated with miRNA-21 in predicting 2-year survival rate.

Targeting Type I Collagen for Cancer Treatment

Collagen is the most abundant protein in animals. Interactions between tumor cells and collagen influence every step of tumor development. Type I collagen is the main fibrillar collagen in the extracellular matrix and is frequently up-regulated during tumorigenesis. The binding of type I collagen to its receptors on tumor cells promotes tumor cell proliferation, epithelial-mesenchymal transition, and metastasis. Type I collagen also regulates the efficacy of tumor therapies, such as chemotherapy, radiotherapy, and immunotherapy. Furthermore, type I collagen fragments are diagnostic markers of metastatic tumors and have prognostic value. Inhibition of type I collagen synthesis has been reported to have anti-tumor effects in animal models. However, collagen has also been shown to possess anti-tumor activity. Therefore, the roles that type I collagen plays in tumor biology are complex and tumor type-dependent. In this review, we discuss the expression and regulation of synthesis of type I collagen, as well as the role up-regulated type I collagen plays in various stages of cancer progression. We also discuss the role of collagen in tumor therapy. Finally, we highlight several recent approaches targeting type I collagen for cancer treatment. This article is protected by copyright. All rights reserved.

MicroRNAs: Emerging Regulators of Metastatic Bone Disease in Breast Cancer

Bone metastasis is a frequent complication in patients with advanced breast cancer. Once in the bone, cancer cells disrupt the tightly regulated cellular balance within the bone microenvironment, leading to excessive bone destruction and further tumor growth. Physiological and pathological interactions in the bone marrow are mediated by cell-cell contacts and secreted molecules that include soluble proteins as well as RNA molecules. MicroRNAs (miRNAs) are short non-coding RNAs that post-transcriptionally interfere with their target messenger RNA (mRNA) and subsequently reduce protein abundance. Since their discovery, miRNAs have been identified as critical regulators of physiological and pathological processes, including breast cancer and associated metastatic bone disease. Depending on their targets, miRNAs can exhibit pro-tumorigenic or anti-tumorigenic functions and serve as diagnostic and prognostic biomarkers. These properties have encouraged pre-clinical and clinical development programs to investigate miRNAs as biomarkers and therapeutic targets in various diseases, including metastatic cancers. In this review, we discuss the role of miRNAs in metastatic bone disease with a focus on breast cancer and the bone microenvironment and elaborate on their potential use for diagnostic and therapeutic purposes in metastatic bone disease and beyond.

Secreted Non-Coding RNAs: Functional Impact on the Tumor Microenvironment and Clinical Relevance in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subtype of breast carcinoma characterized by poor prognosis and high rate of metastasis. Current treatment is based on chemo- and/or radiotherapy and surgery. TNBC is devoid of estrogen, progesterone and HER2 receptors. Although precision medicine has come a long way to ameliorate breast cancer disease management, targeted therapies for the treatment of TNBC patients are still limited. Mounting evidence has shown that non-coding RNAs (ncRNAs) drive many oncogenic processes at the basis of increased proliferation, invasion and angiogenesis in TNBC, strongly contributing to tumor progression and resistance to treatments. Many of these ncRNAs are secreted in the tumor microenvironment (TME) and impinge on the activity of the diverse immune and stromal cell types infiltrating the TME. Importantly, secreted ncRNAs may be detected as circulating molecules in serum/plasma from cancer patients and are emerging a promising diagnostic/therapeutic tools in TNBC. This review aims to discuss novel insights about the role of secreted circulating ncRNAs in the intercellular communication in the tumor microenvironment and their potential clinical use as diagnostic and prognostic non-invasive biomarkers in TNBC.

Exosomes in the Healthy and Malignant Bone Marrow Microenvironment

The bone marrow (BM) is a complex organ that sustains hematopoiesis via mechanisms involving the microenvironment. The microenvironment includes several cell types, neurotransmitters from innervated fibers, growth factors, extracellular matrix proteins, and extracellular vesicles. The main function of the BM is to regulate hematopoietic function to sustain the production of blood and immune cells. However, the BM microenvironment can also accommodate the survival of malignant cells. A major mechanism by which the cancer cells communicate with cells of the BM microenvironment is through the exchange of exosomes, a subset of extracellular vesicles that deliver molecular signals bidirectionally between malignant and healthy cells. The field of exosomes is an active area of investigation since an understanding of how the exosomal packaging, cargo, and production can be leveraged therapeutically to deter cancer progression and sensitize malignant cells to other therapies. Altogether, this chapter discusses the crucial role of exosomes in the development and progression of BM-associated cancers, such as hematologic malignancies and marrow-metastatic breast cancer. Exosome-based therapeutic strategies and their limitations are also considered.

Mutual Modulation Between Extracellular Vesicles and Mechanoenvironment in Bone Tumors

The bone microenvironment homeostasis is guaranteed by the balanced and fine regulated bone matrix remodeling process. This equilibrium can be disrupted by cancer cells developed in the bone (primary bone cancers) or deriving from other tissues (bone metastatic lesions), through a mechanism by which they interfere with bone cells activities and alter the microenvironment both biochemically and mechanically. Among the factors secreted by cancer cells and by cancer-conditioned bone cells, extracellular vesicles (EVs) are described to exert pivotal roles in the establishment and the progression of bone cancers, by conveying tumorigenic signals targeting and transforming normal cells. Doing this, EVs are also responsible in modulating the production of proteins involved in regulating matrix stiffness and/or mechanotransduction process, thereby altering the bone mechanoenvironment. In turn, bone and cancer cells respond to deregulated matrix stiffness by modifying EV production and content, fueling the vicious cycle established in tumors. Here, we summarized the relationship between EVs and the mechanoenvironment during tumoral progression, with the final aim to provide some innovative perspectives in counteracting bone cancers.

MicroRNA-106a regulates autophagy-related cell death and EMT by targeting TP53INP1 in lung cancer with bone metastasis

Bone metastasis is one of the most serious complications in lung cancer patients. MicroRNAs (miRNAs) play important roles in tumour development, progression and metastasis. A previous study showed that miR-106a is highly expressed in the tissues of lung adenocarcinoma with bone metastasis, but its mechanism remains unclear. In this study, we showed that miR-106a expression is dramatically increased in lung cancer patients with bone metastasis (BM) by immunohistochemical analysis. MiR-106a promoted A549 and SPC-A1 cell proliferation, migration and invasion in vitro. The results of bioluminescence imaging (BLI), micro-CT and X-ray demonstrated that miR-106a promoted bone metastasis of lung adenocarcinoma in vivo. Mechanistic investigations revealed that miR-106a upregulation promoted metastasis by targeting tumour protein 53-induced nuclear protein 1 (TP53INP1)-mediated metastatic progression, including cell migration, autophagy-dependent death and epithelial-mesenchymal transition (EMT). Notably, autophagy partially attenuated the effects of miR-106a on promoting bone metastasis in lung adenocarcinoma. These findings demonstrated that restoring the expression of TP53INP1 by silencing miR-106a may be a novel therapeutic strategy for bone metastatic in lung adenocarcinoma.

A glitch in the matrix: organ-specific matrisomes in metastatic niches

Modification of the extracellular matrix (ECM) is a critical aspect of developing a metastasis-supportive organ niche. Recent work investigating ECM changes that facilitate metastasis has revealed ways in which different metastatic organ niches are similar as well as the distinct characteristics that make them unique. In this review, we present recent findings regarding how ECM modifications support metastasis in four frequent metastatic sites: the lung, liver, bone, and brain. We discuss ways in which these modifications are shared between metastatic organs as well as features specific to each location. We also discuss areas of technical innovation that could be advantageous to future research and areas of inquiry that merit further investigation.

Bone Metastatic Breast Cancer: Advances in Cell Signaling and Autophagy Related Mechanisms

Bone metastasis is a frequent complication of breast cancer with nearly 70% of metastatic breast cancer patients developing bone metastasis during the course of their disease. The bone represents a dynamic microenvironment which provides a fertile soil for disseminated tumor cells, however, the mechanisms which regulate the interactions between a metastatic tumor and the bone microenvironment remain poorly understood. Recent studies indicate that during the metastatic process a bidirectional relationship between metastatic tumor cells and the bone microenvironment begins to develop. Metastatic cells display aberrant expression of genes typically reserved for skeletal development and alter the activity of resident cells within the bone microenvironment to promote tumor development, resulting in the severe bone loss. While transcriptional regulation of the metastatic process has been well established, recent findings from our and other research groups highlight the role of the autophagy and secretory pathways in interactions between resident and tumor cells during bone metastatic tumor growth. These reports show high levels of autophagy-related markers, regulatory factors of the autophagy pathway, and autophagy-mediated secretion of matrix metalloproteinases (MMP's), receptor activator of nuclear factor kappa B ligand (RANKL), parathyroid hormone related protein (PTHrP), as well as WNT5A in bone metastatic breast cancer cells. In this review, we discuss the recently elucidated mechanisms and their crosstalk with signaling pathways, and potential therapeutic targets for bone metastatic disease.

Extracellular Vesicles and Bone-Associated Cancer

PURPOSE OF REVIEW

In this review, we describe the biology of extracellular vesicles (EV) and how they contribute to bone-associated cancers.

RECENT FINDINGS

Crosstalk between tumor and bone has been demonstrated to promote tumor and metastatic progression. In addition to direct cell-to-cell contact and soluble factors, such as cytokines, EVs mediate crosstalk between tumor and bone. EVs are composed of a heterogenous group of membrane-delineated vesicles of varying size range, mechanisms of formation, and content. These include apoptotic bodies, microvesicles, large oncosomes, and exosomes. EVs derived from primary tumors have been shown to alter bone remodeling and create formation of a pre-metastatic niche that favors development of bone metastasis. Similarly, EVs from marrow stromal cells have been shown to promote tumor progression. Additionally, EVs can act as therapeutic delivery vehicles due to their low immunogenicity and targeting specificity. EVs play critical roles in intercellular communication. Multiple classes of EVs exist based on size on mechanism of formation. In addition to a role in pathophysiology, EVs can be exploited as therapeutic delivery vehicles.

MicroRNAs and Their Roles in Breast Cancer Bone Metastasis

Bone metastasis occurs in advanced stages of breast cancer, worsening the quality of life and increasing the mortality of patients. Current treatments for bone metastasis are only palliative, and efficient therapeutic targets need to be still identified. MicroRNAs (miRNAs) are a large class of small non-coding RNAs that regulate gene expression within cells. Interestingly, the expression of certain miRNAs has been associated with several stages of bone metastasis progression, highlighting the importance of these small RNAs during the course of the metastatic disease. In this review, we aim to summarise the most recent findings on miRNAs and their mRNA targets in driving breast cancer bone metastasis. Furthermore, we discuss the possibility to use miRNAs as direct therapeutic targets or as advanced therapies for breast cancer bone metastasis, as well as their potential as predictive biomarkers of bone metastasis for an early diagnosis and a better tailoring of therapies for cancer patients.

MicroRNAs in Metastasis and the Tumour Microenvironment

Metastasis is the process whereby cancer cells migrate from the primary tumour site to colonise the surrounding or distant tissue or organ. Metastasis is the primary cause of cancer-related mortality and approximately half of all cancer patients present at diagnosis with some form of metastasis. Consequently, there is a clear need to better understand metastasis in order to develop new tools to combat this process. MicroRNAs (miRNAs) regulate gene expression and play an important role in cancer development and progression including in the metastatic process. Particularly important are the roles that miRNAs play in the interaction between tumour cells and non-tumoral cells of the tumour microenvironment (TME), a process mediated largely by circulating miRNAs contained primarily in extracellular vesicles (EVs). In this review, we outline the accumulating evidence for the importance of miRNAs in the communication between tumour cells and the cells of the TME in the context of the pre-metastatic and metastatic niche.

Current Status of MicroRNAs that Target the Wnt Signaling Pathway in Regulation of Osteogenesis and Bone Metabolism: A Review

The directional differentiation of bone mesenchymal stem cells (BMSCs) is regulated by a variety of transcription factors and intracellular signaling pathways. In the past, it was thought that the directional differentiation of BMSCs was related to transforming growth factors, such as bone morphogenetic protein (BMP) and MAPK pathway. However, in recent years, some scholars have pointed out that the Wnt signaling pathway, which is a necessary complex network of protein interactions for biological growth and development, takes a significant role in this process and plays a major part in regulating the development of osteoblasts by exerting signal transduction into cells. Also, they have proved the Wnt protein therapeutic truly have positive effects on the viability and osteogenic capacity of bone graft. Recent studies have shown that microRNAs (miRNAs) play an important regulatory role in this process. MiRNAs such as miRNA-218, miRNA-335, miRNA-29, microRNA-30 and other miRNAs exert negative or positive effects on some crucial molecules in the Wnt/β-catenin pathway, which in turn affect bone metabolism and osteopathy. Thus, miRNAs have been suggested as therapeutic targets for some metabolic bone diseases. This article aims to provide an update on the current status of microRNAs that target the Wnt signaling pathway in the regulation of osteogenesis and bone metabolism and includes a discussion of future areas of research, which can be a theoretical basis for bone metabolism-related diseases.

Extracellular Vesicles: Novel Opportunities to Understand and Detect Neoplastic Diseases

With a size range from 30 to 1000 nm, extracellular vesicles (EVs) are one of the smallest cell components able to transport biologically active molecules. They mediate intercellular communications and play a fundamental role in the maintenance of tissue homeostasis and pathogenesis in several types of diseases. In particular, EVs actively contribute to cancer initiation and progression, and there is emerging understanding of their role in creation of the metastatic niche. This fact underlies the recent exponential growth in EV research, which has improved our understanding of their specific roles in disease and their potential applications in diagnosis and therapy. EVs and their biomolecular cargo reflect the state of the diseased donor cells, and can be detected in body fluids and exploited as biomarkers in cancer and other diseases. Relatively few studies have been published on EVs in the veterinary field. This review provides an overview of the features and biology of EVs as well as recent developments in EV research including techniques for isolation and analysis, and will address the way in which the EVs released by diseased tissues can be studied and exploited in the field of veterinary pathology. Uniquely, this review emphasizes the important contribution that pathologists can make to the field of EV research: pathologists can help EV scientists in studying and confirming the role of EVs and their molecular cargo in diseased tissues and as biomarkers in liquid biopsies.

Restoring Tissue Homeostasis at Metastatic Sites: A Focus on Extracellular Vesicles in Bone Metastasis

Bone is the most common site of cancer metastasis and the spread of cancer cells to the bone is associated with poor prognosis, pain, increased risk of fractures, and hypercalcemia. The bone marrow microenvironment is an attractive place for tumor dissemination, due to the dynamic network of non-malignant cells. In particular, the alteration of the bone homeostasis favors the tumor homing and the consequent osteolytic or osteoblastic lesions. Extracellular vesicles (EVs) are reported to be involved in the metastatic process, promoting tumor invasion, escape from immune surveillance, extravasation, extracellular matrix remodeling, and metastasis, but the role of EVs in bone metastases is still unclear. Current results suggest the ability of tumor derived EVs in promoting bone localization and metastasis formation, altering the physiological balance between bone destruction and new bone depositions. Moreover, EVs from the bone marrow niche may support the onset of tumor metastasis. This review summarizes recent findings on the role of EVs in the pathological alterations of homeostasis that occur during bone metastasis to show novel potential EV-based therapeutic options to inhibit metastasis formation.

miRNAs: Critical mediators of breast cancer metastatic programming

MicroRNA mediated aberrant gene regulation has been implicated in several diseases including cancer. Recent research has highlighted the role of epigenetic modulation of the complex process of breast cancer metastasis by miRNAs. miRNAs play a crucial role in the process of metastatic evolution by facilitating alterations in the phenotype of tumor cells and the tumor microenvironment that promote this process. They act as critical determinants of the multi-step progression starting from carcinogenesis all the way to organotropism. In this review, we focus on the current understanding of the compelling role of miRNAs in breast cancer metastasis.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial-mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Regulators at Every Step—How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Personal Medicine and Bone Metastases: Biomarkers, Micro-RNAs and Bone Metastases

Bone metastasis is a major cause of morbidity within solid tumours of the breast, prostate, lung and kidney. Metastasis to the skeleton is associated with a wide range of complications including bone fractures, spinal cord compression, hypercalcaemia and increased bone pain. Improved treatments for bone metastasis, such as the use of anti-bone resorptive bisphosphonate agents, within post-menopausal women have improved disease-free survival; however, these treatments are not without side effects. There is thus a need for biomarkers, which will predict the risk of developing the spread to bone within these cancers. The application of molecular profiling techniques, together with animal model systems and engineered cell-lines has enabled the identification of a series of potential bone-metastasis biomarker molecules predictive of bone metastasis risk. Some of these biomarker candidates have been validated within patient-derived samples providing a step towards clinical utility. Recent developments in multiplex biomarker quantification now enable the simultaneous measurement of up to 96 micro-RNA/protein molecules in a spatially defined manner with single-cell resolution, thus enabling the characterisation of the key molecules active at the sites of pre-metastatic niche formation as well as tumour-stroma signalling. These technologies have considerable potential to inform biomarker discovery. Additionally, a potential future extension of these discoveries could also be the identification of novel drug targets within cancer spread to bone. This chapter summarises recent findings in biomarker discovery within the key bone metastatic cancers (breast, prostate, lung and renal cell carcinoma). Tissue-based and circulating blood-based biomarkers are discussed from the fields of genomics, epigenetic regulation (micro-RNAs) and protein/cell-signalling together with a discussion of the potential future development of these markers towards clinical development.

Extracellular Vesicles and Metastasis

Secretion of cell contents through extracellular vesicles (EVs), such as exosomes and microvesicles, is a fundamental cell behavior. Compared with their normal counterparts, cancer cells are different in the amount and composition of EVs they secrete as a result of intrinsic and extrinsic (microenvironmental) alterations. Although EVs were originally recognized as a means to remove undesired cell components, recent studies show their critical role in mediating intercellular interaction through cargo transport. In cancer, EVs can be transferred between different cancer cell subpopulations and between cancer and normal cells localized inside and outside of the tumor. By regulating various aspects of cellular functions, EVs contribute to tumor heterogeneity and plasticity, vascular remodeling, cancer-niche coevolution, immunomodulation, and establishment of premetastatic niche, all of which are important to the process of metastasis. Recent discoveries on EV-mediated mechanisms lead to a new understanding of the multifaceted changes in tumor and nontumor tissues before and after cancer metastasis, paving the way for new therapeutic strategies.

Framing cancer progression: influence of the organ- and tumour-specific matrisome

The extracellular matrix (ECM) plays a crucial role in regulating organ homeostasis. It provides mechanical and biochemical cues directing cellular behaviour and, therefore, has control over the progression of diseases such as cancer. Recent efforts have greatly enhanced our knowledge of the protein composition of the ECM and its regulators, the so-called matrisome, in healthy and cancerous tissues; yet, an overview of the common signatures and organ-specific ECM in cancer is missing. Here, we address this by taking a detailed approach to review why cancer grows in certain organs, and focus on the influence of the matrisome at primary and metastatic tumour sites. Our in-depth and comprehensive review of the current literature and general understanding identifies important commonalities and distinctions, providing insight into the biology of metastasis, which could pave the way to improve future diagnostics and therapies.

Establishment and characterization of highly osteolytic luminal breast cancer cell lines by intracaudal arterial injection

Bone is one of the most common metastatic sites of breast cancer, and bone metastasis profoundly affects the quality of life of breast cancer patients. Bone metastasis is commonly observed among all the subtypes of breast cancer; however, its molecular mechanism has been analyzed only in triple-negative subtype of breast cancer (TNBC). To characterize the molecular mechanisms of bone metastasis of luminal breast cancer, we established a bone-metastatic model of the MCF7, luminal breast cancer cell line, with enhanced osteolytic activity by intracaudal arterial injection (CAI). Pathological analysis of the established cell lines revealed that they exhibited fierce osteolytic ability by promoting osteoclast differentiation and activity. The signature genes extracted from highly osteolytic MCF7 cell lines were differed from those of bone-metastatic TNBC cell lines. Our results suggest that unique mechanisms of osteolysis in bone-metastatic lesions of luminal breast cancer. In addition, several up-regulated genes in MCF7-BM (Bone Metastasis) 02 cell lines correlated with poor prognosis with luminal breast cancer patients. Our findings support further study on the bone-metastatic mechanisms of luminal breast cancer.

MicroRNA-218 inhibits type I interferon production and facilitates virus immune evasion via targeting RIG-I

The host protective immunity against viral infection requires the effective detection of viral antigens and the subsequent production of type I interferons (IFNs) by host immune cells. Retinoic acid-inducible gene I (RIG-I) is the crucial signaling element responsible for sensing viral RNA component and initiating the downstream antiviral signaling pathways, leading to the production of type I IFNs. In this work, we identified microRNA-218 (miR-218) as a new virus-induced miRNA that dampens the expression of RIG-I in mouse and human macrophages, leading to the impaired production of type I IFNs. Interfering miR-218 expression rescued RIG-I-mediated antiviral signaling and thus protected macrophages from viral infection. Hence, our results provide new understanding of miRNA-mediated viral immune evasion and may be potentially useful for the treatment of viral infection in the future.

Over-expression of CDX2 alleviates breast cancer by up-regulating microRNA let-7b and inhibiting COL11A1 expression

Background

microRNA Let-7 serves as a tumor suppressor by targeting various oncogenic pathways in cancer cells. However, the underlying mechanism of its involvement in breast cancer remains largely unknown. With our research, our endeavor is to explore the role of the CDX2/let-7b/COL11A1 axis in breast cancer cell activities.

Methods

Tumor tissues and adjacent normal tissues were collected from 86 patients with breast cancer. Human breast cancer epithelial cell line MCF-7 was treated with over-expressed CDX2, let-7b mimic, shRNA against COL11A1 and their negative controls. The expression of CDX2, let-7b, and COL11A1 in the tissues and cells was determined by RT-qPCR. Interactions among CDX2, let-7b, and COL11A1 were detected by ChIP and dual-luciferase reporter assay, respectively. After different transfections, cell invasion, migration, and proliferation abilities were determined by Transwell and EdU assays. Lastly, tumor xenografts in nude mice were established and hematoxylin and eosin staining was performed to assess the tumor growth and lymph node metastasis.

Results

CDX2 and let-7b were poorly expressed in breast cancer cells and tissues. CDX2 bound to let-7b and promoted the expression of let-7b, which contrarily inhibited the expression of COL11A1. Cancer cell proliferation, invasion, migration, and metastasis were stimulated when CDX2 and let-7b were depleted or COL11A1 was over-expressed. Xenograft tumors growth and metastasis were in accordance with the results of cellular experiments.

Conclusion

In agreement with these observations, we could reach a conclusion that CDX2 could promote let-7b expression, which may exert an inhibitory effect on the proliferation, migration, and metastasis of breast cancer cells via repressing the expression of COL11A1, providing a novel therapeutic strategy for the treatment of metastatic breast cancer.

Novel Techniques to Study the Bone-Tumor Microenvironment

Many cancers commonly metastasize to bone. After entering the bone, cancer cells can interact with surrounding stromal cells, which ultimately influences metastasis progression. Extracellular vesicles, direct cell contact and gap junctions, and cytokines are all mechanisms of intercellular communication that have been observed to occur in the bone microenvironment. These methods of cellular crosstalk can occur between cancer cells and a variety of stromal cells, with each interaction having a different impact on cancer progression. Communication between cancer cells and bone-resident cells has previously been implicated in processes such as cancer cell trafficking and arrest in bone, cancer cell dormancy, cancer cell reactivation, and proliferation. In this chapter we review innovative techniques and model systems that can be used to study bidirectional crosstalk between cancer cells and stromal cells in the bone, with an emphasis specifically on bone-metastatic breast cancer. Investigating how metastatic cancer cells interact with, and are influenced by, the bone microenvironment is crucial to better understanding of the progression of bone metastasis.

Non-coding RNAs in bone remodelling and bone metastasis: Mechanisms of action and translational relevance

Bone metastases are frequent complications in patients with advanced cancer, which can be fatal or may rapidly impede the quality of life of patients. Current treatments for patients with bone metastases are palliative. Therefore, a better understanding of the molecular mechanisms that precede the overt development of skeletal lesions could lead to better therapeutic interventions. In this review, we present evidence that non-coding RNAs (ncRNAs) such as long ncRNAs, microRNAs, and circular RNAs are emerging as master regulators of bone metastasis formation. We highlight potential opportunities for the therapeutic targeting of ncRNAs. Furthermore, we discuss the possibility that ncRNAs may be used as biomarkers in the context of bone metastases, which might provide insight for improving the response to current bone-targeting therapies. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

The role of collagen in cancer: from bench to bedside

Collagen is the major component of the tumor microenvironment and participates in cancer fibrosis. Collagen biosynthesis can be regulated by cancer cells through mutated genes, transcription factors, signaling pathways and receptors; furthermore, collagen can influence tumor cell behavior through integrins, discoidin domain receptors, tyrosine kinase receptors, and some signaling pathways. Exosomes and microRNAs are closely associated with collagen in cancer. Hypoxia, which is common in collagen-rich conditions, intensifies cancer progression, and other substances in the extracellular matrix, such as fibronectin, hyaluronic acid, laminin, and matrix metalloproteinases, interact with collagen to influence cancer cell activity. Macrophages, lymphocytes, and fibroblasts play a role with collagen in cancer immunity and progression. Microscopic changes in collagen content within cancer cells and matrix cells and in other molecules ultimately contribute to the mutual feedback loop that influences prognosis, recurrence, and resistance in cancer. Nanoparticles, nanoplatforms, and nanoenzymes exhibit the expected gratifying properties. The pathophysiological functions of collagen in diverse cancers illustrate the dual roles of collagen and provide promising therapeutic options that can be readily translated from bench to bedside. The emerging understanding of the structural properties and functions of collagen in cancer will guide the development of new strategies for anticancer therapy.

The Bone Extracellular Matrix as an Ideal Milieu for Cancer Cell Metastases

Bone is a preferential site for cancer metastases, including multiple myeloma, prostate, and breast cancers.The composition of bone, especially the extracellular matrix (ECM), make it an attractive site for cancer cell colonization and survival. The bone ECM is composed of living cells embedded within a matrix composed of both organic and inorganic components. Among the organic components, type I collagen provides the tensile strength of bone. Inorganic components, including hydroxyapatite crystals, are an integral component of bone and provide bone with its rigidity. Under normal circumstances, two of the main cell types in bone, the osteoblasts and osteoclasts, help to maintain bone homeostasis and remodeling through cellular communication and response to biophysical signals from the ECM. However, under pathological conditions, including osteoporosis and cancer, bone remodeling is dysregulated. Once in the bone matrix, disseminated tumor cells utilize normal products of bone remodeling, such as collagen type I, to fuel cancer cell proliferation and lesion outgrowth. Models to study the complex interactions between the bone matrix and metastatic cancer cells are limited. Advances in understanding the interactions between the bone ECM and bone metastatic cancer cells are necessary in order to both regulate and prevent metastatic cancer cell growth in bone.