Targeting initial tumour-osteoclast spatiotemporal interaction to prevent bone metastasis.

Bone is the most common site of metastasis, and although low proliferation and immunoediting at the early stage make existing treatment modalities less effective, the microenvironment-inducing behaviour could be a target for early intervention. Here we report on a spatiotemporal coupling interaction between tumour cells and osteoclasts, and named the tumour-associated osteoclast 'tumasteoclast'-a subtype of osteoclasts in bone metastases induced by tumour-migrasome-mediated cytoplasmic transfer. We subsequently propose an in situ decoupling-killing strategy in which tetracycline-modified nanoliposomes encapsulating sodium bicarbonate and sodium hydrogen phosphate are designed to specifically release high concentrations of hydrogen phosphate ions triggered by tumasteoclasts, which depletes calcium ions and forms calcium-phosphorus crystals. This can inhibit the formation of migrasomes for decoupling and disrupt cell membrane for killing, thereby achieving early prevention of bone metastasis. This study provides a research model for exploring tumour cell behaviour in detail and a proof-of-concept for behaviour-targeting strategy.

Immune Modulation with RANKL Blockade through Denosumab Treatment in Patients with Cancer.

Denosumab is a fully human mAb that binds receptor activator of NFκB ligand (RANKL). It is routinely administered to patients with cancer to reduce the incidence of new bone metastasis. RANK-RANKL interactions regulate bone turnover by controlling osteoclast recruitment, development, and activity. However, these interactions also can regulate immune cells including dendritic cells and medullary thymic epithelial cells. Inhibition of the latter results in reduced thymic negative selection of T cells and could enhance the generation of tumor-specific T cells. We examined whether administering denosumab could modify modulate circulating immune cells in patients with cancer. Blood was collected from 23 patients with prostate cancer and 3 patients with renal cell carcinoma, all of whom had advanced disease and were receiving denosumab, prior to and during denosumab treatment. Using high-dimensional mass cytometry, we found that denosumab treatment by itself induced modest effects on circulating immune cell frequency and activation. We also found minimal changes in the circulating T-cell repertoire and the frequency of new thymic emigrants with denosumab treatment. However, when we stratified patients by whether they were receiving chemotherapy and/or steroids, patients receiving these concomitant treatments showed significantly greater immune modulation, including an increase in the frequency of natural killer cells early and classical monocytes later. We also saw broad induction of CTLA-4 and TIM3 expression in circulating lymphocytes and some monocyte populations. These findings suggest that denosumab treatment by itself has modest immunomodulatory effects, but when combined with conventional cancer treatments, can lead to the induction of immunologic checkpoints. See related Spotlight by Nasrollahi and Davar, p. 383.

Prevention of Skeletal-Related Events With Extended-Interval Denosumab: A Review of the Literature.

OBJECTIVE: To review published clinical trial data related to efficacy and safety of administering denosumab at extended dosing intervals for prevention of skeletal-related events (SREs) in cancer patients. DATA SOURCES: A literature search of PubMed was performed (January 2006 to February 2023) using the following search terms: denosumab, bone metastasis, bone lesions, and lytic lesions. Abstracts from conferences, article bibliographies, and product monographs were also reviewed. STUDY SELECTION AND DATA EXTRACTION: Relevant English-language studies were considered. DATA SYNTHESIS: Early phase II denosumab trials included treatment arms that utilized extended-interval denosumab, and various retrospective reviews, meta-analyses, and prospective trials have included extended-interval regimens. Most recently, the ongoing randomized REDUSE trial is comparing the efficacy and safety of extended-interval denosumab to standard dosing. At this time, the best available data are restricted to small, randomized trials not designed to compare efficacy and safety of extended-interval denosumab to conventional dosing and did not use consistent endpoints. Furthermore, primary endpoints of available trials largely consisted of surrogate markers of efficacy that may not be reflective of clinical outcomes. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Historically, denosumab has been dosed at 4-week intervals for prevention of SREs. If efficacy is maintained, extending the dosing interval could potentially reduce toxicity, drug cost, and clinic visits compared to every 4-week dosing. CONCLUSIONS: At this time, data demonstrating efficacy and safety of extended-interval denosumab remain limited, and the results of the REDUSE trial are eagerly anticipated to help answer remaining questions.

The bone-muscle connection in breast cancer: implications and therapeutic strategies to preserve musculoskeletal health.

Breast cancer and its therapies frequently result in significant musculoskeletal morbidity. Skeletal complications include bone metastases, pain, bone loss, osteoporosis, and fracture. In addition, muscle loss or weakness occurring in both the metastatic and curative setting is becoming increasingly recognized as systemic complications of disease and treatment, impacting quality of life, responsiveness to therapy, and survival. While the anatomical relationship between bone and muscle is well established, emerging research has led to new insights into the biochemical and molecular crosstalk between the skeletal and muscular systems. Here, we review the importance of both skeletal and muscular health in breast cancer, the significance of crosstalk between bone and muscle, and the influence of mechanical signals on this relationship. Therapeutic exploitation of signaling between bone and muscle has great potential to prevent the full spectrum of musculoskeletal complications across the continuum of breast cancer.

Use of Adjuvant Bisphosphonates and Other Bone-Modifying Agents in Breast Cancer: ASCO-OH (CCO) Guideline Update.

PURPOSE: To update recommendations of the American Society of Clinical Oncology (ASCO)-Ontario Health (Cancer Care Ontario [CCO]) adjuvant bone-modifying agents in breast cancer guideline. METHODS: An Expert Panel conducted a systematic review to identify new, potentially practice-changing data. RESULTS: Four articles met eligibility criteria and form the evidentiary basis for revision of the previous recommendations. RECOMMENDATIONS: Adjuvant bisphosphonate therapy should be discussed with all postmenopausal patients (natural or therapy-induced) with primary breast cancer, irrespective of hormone receptor status and human epidermal growth factor receptor 2 status, who are candidates to receive adjuvant systemic therapy. Adjuvant bisphosphonates, if used, are not substitutes for standard anticancer modalities. The benefit of adjuvant bisphosphonate therapy will vary depending on the underlying risk of recurrence and is associated with a modest improvement in overall survival. The NHS PREDICT tool provides estimates of the benefit of adjuvant bisphosphonate therapy and may aid in decision making. Factors influencing the decision to recommend adjuvant bisphosphonate use should include patients' risk of recurrence, risk of side effects, financial toxicity, drug availability, patient preferences, comorbidities, and life expectancy. When an adjuvant bisphosphonate is used to prevent breast cancer recurrence, the therapeutic options recommended by the Panel include oral clodronate, oral ibandronate, and intravenous zoledronic acid. The Panel supports starting bisphosphonate therapy early, consistent with the points outlined in the parent CCO-ASCO guideline; this is a consensus recommendation. The Panel does not recommend adjuvant denosumab to prevent breast cancer recurrence, because studies did not show a consistent reduction of breast cancer recurrence in any subset of those with early-stage breast cancer.Additional information can be found at www.asco.org/breast-cancer-guideline.

Targeting Bone Metastases Signaling Pathway Using Moringa oleifera Seed Nutri-miRs: A Cross Kingdom Approach.

Moringa oleifera is a medicinally important plant that has various medical and nutritional uses. Plant miRNAs are a class of non-coding endogenous small RNAs that regulate human-specific mRNA but the mechanistic actions are largely unknown. Here, in this study, we aim to explore the mechanistic action and influence of M. oleifera seed miRNAs on vital human target genes using computer based approaches. The M. oleifera seed miRNAs sequence was taken from published data and identified its human gene targets using a psRNA target analysis server. We identified 94 miRNAs that are able to significantly regulate 47 human target genes, which has enormous biological and functional importance. Out of 47 human targeted genes, 23 genes were found to be associated with PI3K-AKT, RUNX, and MAPK1/MAPK3 signaling pathway which has shown to play key roles in bone metastases during cancer progression. The M. oleifera seed miRNAs hold a strong potential for future research that might uncover the possibility of miRNA-facilitated cross-kingdom regulation and therapeutic targets for bone metastases.

Curcumin Inhibition of TGFß signaling in bone metastatic breast cancer cells and the possible role of oxidative metabolites.

TGFß signaling promotes progression of bone-metastatic (BMET) breast cancer (BCa) cells by driving tumor-associated osteolysis, a hallmark of BCa BMETs, thus allowing for tumor expansion within bone. Turmeric-derived bioactive curcumin, enriched in bone via local enzymatic deconjugation of inactive circulating curcumin-glucuronides, inhibits osteolysis and BMET progression in human xenograft BCa BMET models by blocking tumoral TGFß signaling pathways mediating osteolysis. This is a unique antiosteolytic mechanism in contrast to current osteoclast-targeting therapeutics. Therefore, experiments were undertaken to elucidate the mechanism for curcumin inhibition of BCa TGFß signaling and the application of this finding across multiple BCa cell lines forming TGFß-dependent BMETs, including a possible role for bioactive curcumin metabolites in mediating these effects. Immunoblot analysis of TGFß signaling proteins in bone tropic human (MDA-SA, MDA-1833, MDA-2287) and murine (4T1) BCa cells revealed uniform curcumin blockade of TGFß-induced Smad activation due to down-regulation of plasma membrane associated TGFßR2 and cellular receptor Smad proteins that propagate Smad-mediated gene expression, resulting in downregulation of PTHrP expression, the osteolytic factor driving in vivo BMET progression. With the exception of early decreases in TGFßR2, inhibitory effects appeared to be mediated by oxidative metabolites of curcumin and involved inhibition of gene expression. Interestingly, while not contributing to changes in Smad-mediated TGFß signaling, curcumin caused early activation of MAPK signaling in all cell lines, including JNK, an effect possibly involving interactions with TGFßR2 within lipid rafts. Treatment with curcumin or oxidizable analogs of curcumin may have clinical relevancy in the management of TGFß-dependent BCa BMETs.

Perillaldehyde inhibits bone metastasis and receptor activator of nuclear factor-κB ligand (RANKL) signaling-induced osteoclastogenesis in prostate cancer cell lines.

Perillaldehyde (PAH), one of the active ingredients of the traditional Chinese medicine (TCM) plant Perilla frutescens, is widely used and exerts crucial anti-cancer activities. The aim of current study is to illustrate the potential mechanisms of PAH-mediated regulation of bone metastasis and osteoclastogenesis in prostate cancer (PCa) cell lines. Effects of PAH on proliferation, invasion and migration of PC-3 cells were assessed with the Cell Counting Kit-8 (CCK-8) assay and Transwell assays, respectively. Effects of PAH on stem cell characteristics of PC-3 cells were evaluated by cell-matrix adhesion assay, colony formation assay, spheroid formation assay, as well as western blot . The anti-metastasis and anti-osteoclastogenesis activity of PAH in RAW264.7 cells was examined by osteoclast differentiation assay and western blot. The protein levels of CD133 and CD44 in PC-3 cells and the activity of nuclear factor kappa B (NF-κB) signaling pathway in RAW264.7 cells were measured by western blot. PAH suppressed proliferation, invasion and migration of PC-3 cells, prevented stem cell characteristics including cell-matrix adhesion, colony formation, spheroid formation as well as CD133 and CD44 expression. PAH inhibited bone metastasis and osteoclastogenesis via repressing the activation of NF-κB pathway as well as (RANKL) - and cancer cell-induced osteoclastogenesis in PCa cells. These findings suggested the potential therapeutic effects of PAH on the metastasis of patients with PCa.

Downregulation of the Proton-Activated Cl- Channel TMEM206 Inhibits Malignant Properties of Human Osteosarcoma Cells.

Transmembrane protein 206 (TMEM206), a proton-activated chloride channel, has been implicated in various biochemical processes, including bone metabolism, and has emerged as a novel cancer-related protein in multiple tumor types. However, its role in primary malignant bone tumors, particularly in osteosarcoma (OS), remains unclear. This study is aimed at exploring the effects of TMEM206 gene silencing on the proliferation, migration, invasion, and metastasis of human OS cells in vitro and in vivo using an shRNA-knockdown strategy. We found that TMEM206 is frequently overexpressed and that high levels of TMEM206 correlated with clinical stage and pulmonary metastasis in patients with OS. We provided evidence that TMEM206-silenced OS cancer cells exhibit decreased proliferation, migration, and invasion in vitro. Mechanistically, we identified ß-catenin, a key member of Wnt/ß-catenin signaling, as a downstream effector of TMEM206. TMEM206 silencing inhibits the Wnt/ß-catenin signaling pathway in expression rescue experiments, confirming that TMEM206 silencing attenuates OS cell tumorigenic behavior, at least in part, via the ß-catenin mediated downregulation of Wnt/ß-catenin signaling. More importantly, TMEM206 knockdown-related phenotype changes were replicated in a xenograft nude mouse model where pulmonary metastases of OS cells were suppressed. Together, our results demonstrate that silencing TMEM206 negatively modulates the Wnt/ß-catenin signaling pathway via ß-catenin to suppress proliferation, migration, invasion, and metastasis in OS carcinogenesis, suggesting TMEM206 as a potential oncogenic biomarker and a potential target for OS treatment.

Melatonin Inhibits Osteoclastogenesis and Osteolytic Bone Metastasis: Implications for Osteoporosis.

Osteoblasts and osteoclasts are major cellular components in the bone microenvironment and they play a key role in the bone turnover cycle. Many risk factors interfere with this cycle and contribute to bone-wasting diseases that progressively destroy bone and markedly reduce quality of life. Melatonin (N-acetyl-5-methoxy-tryptamine) has demonstrated intriguing therapeutic potential in the bone microenvironment, with reported effects that include the regulation of bone metabolism, acceleration of osteoblastogenesis, inhibition of osteoclastogenesis and the induction of apoptosis in mature osteoclasts, as well as the suppression of osteolytic bone metastasis. This review aims to shed light on molecular and clinical evidence that points to possibilities of melatonin for the treatment of both osteoporosis and osteolytic bone metastasis. It appears that the therapeutic qualities of melatonin supplementation may enable existing antiresorptive osteoporotic drugs to treat osteolytic metastasis.

Intracellular Signaling Responses Induced by Radiation within an In Vitro Bone Metastasis Model after Pre-Treatment with an Estrone Analogue.

2-Ethyl-3-O-sulfamoyl-estra-1,3,5(10)16-tetraene (ESE-16) is an in silico-designed estradiol analogue which has improved the parent compound's efficacy in anti-cancer studies. In this proof-of-concept study, the potential radiosensitizing effects of ESE-16 were investigated in an in vitro deconstructed bone metastasis model. Prostate (DU 145) and breast (MDA-MB-231) tumor cells, osteoblastic (MC3T3-E1) and osteoclastic (RAW 264.7) bone cells and human umbilical vein endothelial cells (HUVECs) were representative components of such a lesion. Cells were exposed to a low-dose ESE-16 for 24 hours prior to radiation at non-lethal doses to determine early signaling and molecular responses of this combination treatment. Tartrate-resistant acid phosphatase activity and actin ring formation were investigated in osteoclasts, while cell cycle progression, reactive oxygen species generation and angiogenic protein expression were investigated in HUVECs. Increased cytotoxicity was evident in tumor and endothelial cells while bone cells appeared to be spared. Increased mitotic indices were calculated, and evidence of increased deoxyribonucleic acid damage with retarded repair, together with reduced metastatic signaling was observed in tumor cells. RAW 264.7 macrophages retained their ability to differentiate into osteoclasts. Anti-angiogenic effects were observed in HUVECs, and expression of hypoxia-inducible factor 1-α was decreased. Through preferentially inducing tumor cell death and potentially inhibiting neovascularization whilst preserving bone physiology, this low-dose combination regimen warrants further investigation for its promising therapeutic application in bone metastases management, with the additional potential of limited treatment side effects.

NMNAT1 Is a Survival Factor in Actinomycin D-Induced Osteosarcoma Cell Death.

Osteosarcoma is a frequent and extremely aggressive type of pediatric cancer. New therapeutic approaches are needed to improve the overall survival of osteosarcoma patients. Our previous results suggest that NMNAT1, a key enzyme in nuclear NAD+ synthesis, facilitates the survival of cisplatin-treated osteosarcoma cells. A high-throughput cytotoxicity screening was performed to identify novel pathways or compounds linked to the cancer-promoting role of NMNAT1. Nine compounds caused higher toxicity in the NMNAT1 KO U2OS cells compared to their wild type counterparts, and actinomycin D (ActD) was the most potent. ActD-treatment of NMNAT1 KO cells increased caspase activity and secondary necrosis. The reduced NAD+ content in NMNAT1 KO cells was further decreased by ActD, which partially inhibited NAD+-dependent enzymes, including the DNA nick sensor enzyme PARP1 and the NAD+-dependent deacetylase SIRT1. Impaired PARP1 activity increased DNA damage in ActD-treated NMNAT1 knockout cells, while SIRT1 impairment increased acetylation of the p53 protein, causing the upregulation of pro-apoptotic proteins (NOXA, BAX). Proliferation was decreased through both PARP- and SIRT-dependent pathways. On the one hand, PARP inhibitors sensitized wild type but not NMNAT1 KO cells to ActD-induced anti-clonogenic effects; on the other hand, over-acetylated p53 induced the expression of the anti-proliferative p21 protein leading to cell cycle arrest. Based on our results, NMNAT1 acts as a survival factor in ActD-treated osteosarcoma cells. By inhibiting both PARP1- and SIRT1-dependent cellular pathways, NMNAT1 inhibition can be a promising new tool in osteosarcoma chemotherapy.

RANKL immunisation inhibits prostate cancer metastasis by modulating EMT through a RANKL-dependent pathway.

Prostate cancer (PCa) morbidity in the majority of patients is due to metastatic events, which are a clinical obstacle. Therefore, a better understanding of the mechanism underlying metastasis is imperative if we are to develop novel therapeutic strategies. Receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL) regulates bone remodelling. Thus, agents that suppress RANKL signalling may be useful pharmacological treatments. Here, we used preclinical experimental models to investigate whether an inactive form of RANKL affects bone metastasis in RANKL-induced PCa. RANKL was associated with epithelial-mesenchymal transition (EMT) and expression of metastasis-related genes in PC3 cells. Therefore, we proposed a strategy to induce anti-cytokine antibodies using mutant RANKL as an immunogen. RANKL promoted migration and invasion of PC3 cells through EMT, and induced a significant increase in binding of ß-catenin to TCF-4, an EMT-induced transcription factor in PCa cells, via mitogen-activated protein kinase and ß-catenin/TCF-4 signalling. Thus, RANKL increased EMT and the metastatic properties of PC3 cells, suggesting a role as a therapeutic target to prevent PCa metastasis. Treatment with mutant RANKL reduced EMT and metastasis of PC3 PCa cells in an experimental metastasis model. Thus, mutant RANKL could serve as a potential vaccine to prevent and treat metastatic PCa.

Targeting Intercellular Communication in the Bone Microenvironment to Prevent Disseminated Tumor Cell Escape from Dormancy and Bone Metastatic Tumor Growth.

Metastasis to the bone is a common feature of many cancers including those of the breast, prostate, lung, thyroid and kidney. Once tumors metastasize to the bone, they are essentially incurable. Bone metastasis is a complex process involving not only intravasation of tumor cells from the primary tumor into circulation, but extravasation from circulation into the bone where they meet an environment that is generally suppressive of their growth. The bone microenvironment can inhibit the growth of disseminated tumor cells (DTC) by inducing dormancy of the DTC directly and later on following formation of a micrometastatic tumour mass by inhibiting metastatic processes including angiogenesis, bone remodeling and immunosuppressive cell functions. In this review we will highlight some of the mechanisms mediating DTC dormancy and the complex relationships which occur between tumor cells and bone resident cells in the bone metastatic microenvironment. These inter-cellular interactions may be important targets to consider for development of novel effective therapies for the prevention or treatment of bone metastases.

Androgen receptor decreases renal cell carcinoma bone metastases via suppressing the osteolytic formation through altering a novel circEXOC7 regulatory axis.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) has gender differences, with the androgen receptor (AR) linked positively with metastasis to the lung. Its linkage to ccRCC bone metastases (RBMs), however, remains unclear. METHODS: In the current study, five human RCC and five RCC bone metastasis tissues were deeply sequenced using Arraystar human circRNA V2.0 microarray. We conducted gain-of-function screening in vitro and in vivo to elucidate the AR's role in the RBM. Loss/gain-of-function was also implemented to verify the roles of related non-coding RNAs and proteins. RESULTS: We uncovered that RBM also has a gender difference showing higher AR expression may be linked to fewer RBMs, which might involve suppressing osteolytic formation. Mechanism dissection indicates that AR can decrease the circular RNA EXOC7 (circEXOC7), expression via enhancing transcription of DHX9, a regulatory protein in circRNA biogenesis. The circEXOC7 can sponge/suppress miR-149-3p resulting in suppressing the CSF1 expression by directly binding to the 3'UTR region of CSF1 mRNA. Results from clinical epidemiological surveys also found that AR has a positive correlation with miR-149-3p and a negative correlation with CSF1 in AR-positive ccRCC tissues. Preclinical studies with Balb/c nude mouse model also validated that targeting this newly verified AR/DHX9/circEXOC7/miR-149-3p/CSF1 signaling via altering circEXOC7 or AR could lead to suppressing the RBM progression. CONCLUSIONS: These data showed that AR/DHX9/circEXOC7/miR-149-3p/CSF1 signaling acts as a valuable feature in the bone metastasis of renal cancer, which may benefit in suppressing the RBM progression.

Novel bone-targeted parathyroid hormone-related peptide antagonists inhibit breast cancer bone metastases.

Patients with advanced breast cancer often develop bone metastases. Treatment is limited to palliative care. Parathyroid hormone (PTH)/parathyroid hormone-related peptide (PTHrP) antagonists for bone metastases failed clinically due to short half-life and inadequate concentration in bone. We synthesized two novel PTHrP antagonists fused to an inert bacterial collagen binding domain (CBD) that directs drugs to bone. PTH(7-33)-CBD is an N-terminal truncated PTHrP antagonist. [W2]PTH(1-33)-CBD is an PTHrP inverse-agonist. The aim of this study was to assess PTH(7-33)-CBD to reduce breast cancer bone metastases and prevent osteolytic destruction in mice and to assess both drugs for apoptosis of breast cancer cells in vitro and inhibition of PTH receptor (PTHR1). PTH(7-33)-CBD (1000 µg/kg, subcutaneous) or vehicle was administered 24 h prior to MDA-MB-231 breast cancer cell inoculation into the tibia marrow. Weekly tumor burden and bone density were measured. Pharmacokinetic analysis of PTH(7-33)-CBD in rat serum was evaluated. Drug effect on cAMP accumulation in SaOS-2 osteosarcoma cells and apoptosis of MDA-MB-231 cells was assessed. PTH(7-33)-CBD reduced MDA-MB-231 tumor burden and osteolytic destruction in mice 4-5 weeks post-treatment. PTH(7-33)-CBD (1000 µg/kg i.v. and subcutaneous) in rats was rapidly absorbed with peak concentration 5-min and terminal half-life 3-h. Bioavailability by the subcutaneous route was 43% relative to the i.v. route. PTH(7-33)-CBD was detected only on rat periosteal bone surfaces that stained positive for collagen-1. PTH(7-33)-CBD and [W2]PTH(1-33)-CBD (10-8M) blocked basal and PTH agonist-induced cAMP accumulation in SaOS-2 osteosarcoma cells. Both drugs induced PTHR1-dependent apoptosis of MDA-MB-231 cells in vitro. Novel bone-targeted PTHrP antagonists represent a new paradigm for treatment of breast cancer bone metastases.

Conditional knockdown of integrin beta-3 reveals its involvement in osteolytic and soft tissue lesions of breast cancer skeletal metastasis.

Integrin ß3 (ITGB3) is probably related to skeletal metastasis, which is the most frequent complication in breast cancer progression. We aimed to define its role and suitability as target for anti-metastatic therapy. We generated two MDA-MB-231 cell clones with conditional miRNA-mediated ITGB3 knockdown for analyzing the resulting effects in vitro regarding mRNA expression, proliferation and migration, as well the impact on skeletal metastasis in a nude rat model. Furthermore, ITGB3 levels were analyzed in exosomes from plasma of rats with skeletal metastases, and from MDA-MB-231 cells incubated with these vesicles, as well as from exosomes secreted by cells with conditional ITGB3 knockdown. This inhibition of ITGB3 expression decreased cellular proliferation and more distinctly inhibited cellular migration. Reduction and even complete remissions of respective soft tissue and osteolytic lesions were detected after ITGB3 knockdown in vivo. Furthermore, ITGB3 levels were increased in exosomes isolated from plasma of rats harboring MDA-MB-231 lesions as well as in respective cells incubated with these vesicles in vitro. ITGB3 was distinctly decreased in exosomes from cells with ITGB3 knockdown. The observed in vitro and in vivo anti-ITGB3 effects can be explained by downregulation of specific genes, which have roles in angiogenesis (NPTN, RRM2), tumor growth (NPTN), energy metabolism (ISCA1), cytokinesis (SEPT11), migration (RRM2, STX6), cell proliferation, invasiveness, senescence, tumorigenesis (RRM2) and vesicle trafficking (SEPT11, STX6). ITGB3 has a role in breast cancer skeletal metastasis via gene expression modulation, as mirrored for ITGB3 in exosomes, thus it could serve as target for anti-metastatic therapy.

Safety evaluation of the canine osteosarcoma vaccine, live Listeria vector.

Canine osteosarcoma (OSA) is an aggressive bone tumour in dogs. Standard-of-care treatment typically results in relatively short survival times; thus, alternative treatments are needed to confer a survival advantage. It has been shown that OSA is an immunogenic tumour, suggesting that immune modulation may result in superior outcomes. A cryopreserved, Listeria-based OSA vaccine was recently developed and an initial study in dogs reported prolonged survival for patients receiving the vaccine in conjunction with standard-of-care. The goal of the current observational study was to report on the safety of the lyophilized formulation of this vaccine (the canine OSA vaccine, live Listeria vector [COV-LLV]) in a group of dogs previously diagnosed with OSA. Forty-nine (49) dogs received the COV-LLV and were included for analysis. Adverse events (AEs) noted during and after vaccinations were recorded. The AEs observed were typically mild and self-limiting, with nausea, lethargy and fever being most common. Four dogs (8%) cultured positive for Listeria (three infections including an amputation site abscess, septic stifle joint and bacterial cystitis; and one dog whose lungs cultured Listeria-positive on necropsy within 24 hours of COV-LLV administration). These cases join the previously reported Listeria-positive thoracic abscess that developed in a canine following use of COV-LLV. Although uncommon, it is important to realize this clinically significant AE is possible in patients treated with live therapeutic Listeria vaccines. As Listeria is zoonotic, caution is required not only for the patient receiving the vaccine, but also for the health care workers and family caring for the patient.

The botanical component p-hydroxycinnamic acid suppresses the growth and bone metastatic activity of human prostate cancer PC-3 cells in vitro.

Bone metastatic prostate cancer is one of the most common malignancies in developed countries and the second leading cause of cancer-related death in men. There remains no effective treatment for metastatic prostate cancer. We investigate here the anticancer effects of botanical component p-hydroxycinnamic acid (HCA) on the PC-3 cells in vitro model of bone metastatic human prostate cancer. Culturing with HCA (10-1000 nM) suppressed colony formation and growth of PC-3 cells. Mechanistically, culturing with HCA decreased protein levels of Ras, PI3K, Akt, MAPK, NF-κB p65 and ß-catenin related to processes of cell signaling and transcription, and it increased levels of p21, p53, retinoblastoma and regucalcin, which are suppressors in carcinogenesis. These alterations can lead to suppression of cell growth. Furthermore, culturing with HCA increased cell death and caspase-3 levels. The effects of HCA on the growth and death of PC-3 cells were blocked by culturing with CH223191, an antagonist of aryl hydrocarbon receptor (AHR), suggesting that HCA effects are partly involved in AHR signaling. Interestingly, HCA suppressed the stimulatory effects of Bay K 8644, an agonist of L-type calcium channel, on the growth of PC-3 cells. Coculturing of PC-3 cells and preosteoblastic MC-3T3 E1 cells increased osteoblastic mineralization. This increase was not attenuated by treatment of HCA that stimulated mineralization. Notably, osteoclastogenesis from preosteoclastic RAW264.7 cells was enhanced by coculturing with PC-3 cells, and this enhancement was suppressed by treatment with HCA (10-1000 nM). Thus, HCA has anticancer effects on bone metastatic human prostate cancer, potentially providing a novel therapeutic tool.