Osteolytic metastasis in breast cancer: effective prevention strategies

Beyond boundaries: unraveling innovative approaches to combat bone-metastatic cancers

Evidence demonstrated that bones, liver, and lungs are the most common metastasis sites in some human malignancies, especially in prostate and breast cancers. Bone is the third most frequent target for spreading tumor cells among these organs and tissues. Patients with bone-metastatic cancers face a grim prognosis characterized by short median survival time. Current treatments have proven insufficient, as they can only inhibit metastasis or tumor progression within the bone tissues rather than providing a curative solution. Gaining a more profound comprehension of the interplay between tumor cells and the bone microenvironment (BME) is of utmost importance in tackling this issue. This knowledge will pave the way for developing innovative diagnostic and therapeutic approaches. This review summarizes the mechanisms underlying bone metastasis and discusses the clinical aspects of this pathologic condition. Additionally, it highlights emerging therapeutic interventions aimed at enhancing the quality of life for patients affected by bone-metastatic cancers. By synthesizing current research, this review seeks to shed light on the complexities of bone metastasis and offer insights for future advancements in patient care.

Simvastatin prevents BMP-2 driven cell migration and invasion by suppressing oncogenic DNMT1 expression in breast cancer cells

Both epigenetic and genetic changes in the cancer genome act simultaneously to promote tumor development and metastasis. Aberrant DNA methylation, a prime epigenetic event, is often observed in various cancer types. The elevated DNA methyltransferase 1 (DNMT1) enzyme creates DNA hypermethylation at CpG islands to drive oncogenic potential. This study emphasized to decipher the molecular mechanism of endogenous regulation of DNMT1 expression for finding upstream signaling molecules. Cancer database analyses found an upregulated DNMT1 expression in most cancer types including breast cancer. Overexpression of DNMT1 showed an increased cell migration, invasion, and stemness potential whereas 5-azacytidine (DNMT1 inhibitor) and siRNA mediated knockdown of DNMT1 exhibited inhibition of such cancer activities in breast cancer MDA-MB-231 and MCF-7 cells. Infact, cancer database analyses further found a positive correlation of DNMT1 transcript with both cholesterol pathway regulatory genes and BMP signaling molecules. Experimental observations documented that the cholesterol-lowering drug, simvastatin decreased DNMT1 transcript as well as protein, whereas BMP-2 treatment increased DNMT1 expression in breast cancer cells. In addition, expression of various key cholesterol regulatory genes was found to be upregulated in response to BMP-2 treatment. Moreover, simvastatin inhibited BMP-2 induced DNMT1 expression in breast cancer cells. Thus, this study for the first time reveals that both BMP-2 signaling and cholesterol pathways could regulate endogenous DNMT1 expression in cancer cells.

Dysregulated cholesterol regulatory genes as a diagnostic biomarker for cancer

BACKGROUND

A dysregulation of cholesterol homeostasis is often seen in various cancer cell types, and elevated cholesterol content and that of its metabolites appears to be crucial for cancer progression and metastasis. Cholesterol is a precursor of various steroid hormones and a key plasma membrane component especially in lipid-rafts, also modulating many intracellular signaling pathways.

METHODS

To provide an insight of dysregulated cholesterol regulatory genes, their transcript levels were analyzed in different cancers and their influence was correlated with the overall survival of cancer patients using cancer database analysis.

RESULTS

This analysis found a set of genes (e.g., ACAT1, RXRA, SOAT1 and SQLE) that were not only often dysregulated, but also had been associated with poorer overall survival in most cancer types. Quantitative reverse transcriptase-polymerase chain reaction analysis revealed elevated SQLE and SOAT1 transcript levels and downregulated expression of RXRA and ACAT1 genes in triple negative breast cancer tissues compared to adjacent control tissues, indicating that this dysregulated expression of the gene signature is a diagnostic marker for breast cancer.

CONCLUSION

For the first time, the present study identified a gene signature associated with the dysregulation of cholesterol homeostasis in cancer cells that may not only be used as a diagnostic marker, but also comprise a promising drug target for the advancement of cancer therapy.

Extracellular Vesicle-Packaged CDH11 and ITGA5 Induce the Premetastatic Niche for Bone Colonization of Breast Cancer Cells

Although most breast cancer metastases in bone cause osteolytic lesions, the osteogenic niche has commonly been described as an initiator of early-stage bone colonization of disseminated cancer cells. Tumor cell-derived extracellular vesicles (EV) have been shown to determine the organotropism of cancer cells by transferring their cargo, such as nucleic acids and proteins, to resident cells at future metastatic sites and preparing a favorable premetastatic niche. Runt-related transcription factor 2 (RUNX2) and its regulated genes have been shown to facilitate the acquisition of osteomimetic features and to enhance the bone metastatic potential of breast cancer cells. In this study, we present in vivo and in vitro evidence to clarify the role of EVs released by breast cancer cells with high RUNX2 expression in the education of osteoblasts to form an osteogenic premetastatic niche. Furthermore, different extracellular vesicular proteins were identified that mediate events subsequent to the specific recognition of tumor-derived EVs by osteoblasts via cadherin 11 (CDH11) and the induction of the osteogenic premetastatic niche by integrin α5 (ITGA5). CDH11high/ITGA5high EVs were demonstrated to be responsible for the formation of a premetastatic niche that facilitates RUNX2 high-expressing breast cancer cell colonization in bone, revealing a potential EV-based premetastatic niche blockage strategy.

SIGNIFICANCE

This study provides mechanistic insights into the generation of an osteogenic premetastatic niche by breast cancer-derived EVs and identifies potential EV-derived diagnostic biomarkers and targets for breast cancer bone metastasis.

[Surgical treatment of patients with chest wall metastases]

OBJECTIVE

To evaluate postoperative outcomes in patients with chest wall metastases.

MATERIAL AND METHODS

We analyzed 40 patients who underwent surgery for chest wall metastatic lesions. Fourteen (35%) patients had sternal lesion, 26 (65%) ones - rib metastases. We used implants for chest wall defect closure in 15 (37.5%) patients. Chest wall repair with autologous tissues was performed in 19 (47.5%) patients.

RESULTS

Median survival was 17 months. Most patients (n=30, 75%) showed improvement in the quality of life according to Karnofsky and EGOG scale after surgery. Continued tumor growth occurred in 4 (10%) patients within 8-16 months after surgery. There were 2 patients who suffered from tumor recurrence accompanied by other metastatic foci (progression). Complications were diagnosed in 5 (12.5%) patients. Tactical errors were identified in 4 (10%) patients and they were associated with progression of cancer in the form of new metastatic foci within 6 months after surgery.

CONCLUSION

Active surgical approach for bone metastases in patients with favorable cancer-related prognosis can improve quality of life and survival at least in case of solitary lesions. New program for treatment strategy selection based on prognosis of life expectancy and algorithms of surgical treatment will reduce the risk of erroneous management and increase its effectiveness.

Osteosarcoma and Metastasis Associated Bone Degradation-A Tale of Osteoclast and Malignant Cell Cooperativity

Cancer-induced bone degradation is part of the pathological process associated with both primary bone cancers, such as osteosarcoma, and bone metastases originating from, e.g., breast, prostate, and colon carcinomas. Typically, this includes a cancer-dependent hijacking of processes also occurring during physiological bone remodeling, including osteoclast-mediated disruption of the inorganic bone component and collagenolysis. Extensive research has revealed the significance of osteoclast-mediated bone resorption throughout the course of disease for both primary and secondary bone cancer. Nevertheless, cancer cells representing both primary bone cancer and bone metastasis have also been implicated directly in bone degradation. We will present and discuss observations on the contribution of osteoclasts and cancer cells in cancer-associated bone degradation and reciprocal modulatory actions between these cells. The focus of this review is osteosarcoma, but we will also include relevant observations from studies of bone metastasis. Additionally, we propose a model for cancer-associated bone degradation that involves a collaboration between osteoclasts and cancer cells and in which both cell types may directly participate in the degradation process.

Forkhead box F2 as a novel prognostic biomarker and potential therapeutic target in human cancers prone to bone metastasis: a meta-analysis

OBJECTIVE

To undertake a systematic review and meta-analysis to evaluate the prognostic value of Forkhead box F2 (FOXF2) levels in different types of cancers prone to bone metastasis.

METHODS

A systematic search of publications listed in electronic databases (The Web of Science, EMBASE®, PubMed®, PMC, Science Direct and CNKI) from inception to 5 November 2020 was conducted. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) were used to assess the relationship between FOXF2 levels and patient prognosis including overall survival (OS) and disease-free survival (DFS).

RESULTS

Sixteen studies enrolling 8461 participants were included in the meta-analysis. High levels of FOXF2 were a predictor of OS (HR: 0.66; 95% CI 0.51, 0.86) and DFS (HR: 0.60; 95% CI 0.48, 0.76). The trim-and-fill analysis, sensitivity analysis and subgroup analyses stratified by the study characteristics confirmed the robustness of the results.

CONCLUSION

These current findings indicate that high FOXF2 levels could be an indicator of a good prognosis in cancer patients with tumours that are prone to bone metastasis. FOXF2 levels might be a clinically important prognostic biomarker.

Anti-obesity Medications in Cancer Therapy: A Comprehensive Insight

The interplay between cancer and obesity is multifactorial and complex with the increased risk of cancer development in obese individuals posing a significant threat. Obesity leads to the upregulation or hyperactivation of several oncogenic pathways in cancer cells, which drives them towards a deleterious phenotype. The cross-talk between cancer and obesity is considered a large contributing factor in the development of chemotherapeutic drug resistance and the resistance to radiotherapy. The link between obesity and the development of cancer is so strong that a medication that demonstrates effectiveness against both conditions would serve as an essential step. In this context, anti-obesity medications provide a worthy list of candidates based on their chemo-preventive potential and chemotherapeutic properties. The current study focuses on exploring the potential of anti-obesity medicines as dual anticancer drugs. These medications target several key signaling pathways (e.g., AMPK, PI3K/Akt/mTOR, MAPK, NF-κB, JNK/ERK), which prove to be crucial for both cancer growth and metastases. Some of these drugs also play an important role in attenuating the signaling and cellular events which incite cancer-obesity cross-talk and demonstrate efficient counteraction of neoplastic transformation. Thus, this review highlights a comprehensive view of the potential use of anti-obesity medicines to treat both cancer and obesity for patients exhibiting both comorbities.

N-arachidonoyl dopamine inhibits epithelial-mesenchymal transition of breast cancer cells through ERK signaling and decreasing the cellular cholesterol

N-acyl dopamines (NADAs) are bioactive lipids of the endovanilloid family with known cytotoxicity for the cancer cells; however, the available data on the participation of the endovanilloids in epithelial-mesenchymal transition (EMT) and cancer stemness are controversial. This study unveils the inhibitory role of N-arachidonoyl dopamine (AA-DA), a typical representative of the NADA family, in breast cancer cell migration, EMT, and stemness. AA-DA treatment also led to a decrease in cholesterol biosynthesis gene expressions, and addition of exogenous cholesterol reverted these AA-DA-mediated inhibitory effects. Notably, AA-DA treatment inhibited the key regulatory gene of the cholesterol biosynthesis pathway, sterol regulatory element-binding protein 1 (SREBP1), with concurrent repression of the endoplasmic reticulum kinase 1/2 (ERK1/2) pathway. Furthermore, U0126, an ERK inhibitor, inhibited SREBP1 and decreased cellular cholesterol level, unwinding the molecular mechanism behind AA-DA-mediated anticancer activity. Thus, we, for the first time, revealed that AA-DA counteracts breast cancer EMT via inhibition of ERK signaling and cholesterol content.