Association of RANKL and EGFR gene expression with bone metastases in patients with metastatic non-small cell lung cancer

Connecting the dots: (RANKL+) extracellular vesicle count in blood plasma in relation to bone metastases, skeletal related events and osimertinib treatment in patients with EGFR mutated non-small cell lung cancer

Background

The biological mechanisms responsible for the different incidences of bone metastases in molecular subgroups of non-small cell lung cancer (NSCLC) are not identified. Extracellular vesicles (EVs) may play a role, as they are involved in organotrophic metastasis. Phosphorylation of epidermal growth factor receptor (EGFR) in exosomes possibly leads to an increase in receptor activator of nuclear factor κB ligand (RANKL) triggering osteoclastogenesis. In search for new biomarkers with focus on EVs and RANKL, we studied in plasma of patients with EGFR + NSCLC the associations between the total concentration of EVs, RANKL+ EVs, RANKL, and osteoprotegerin (OPG) protein levels, osimertinib treatment, presence of bone metastases and skeletal related events (SREs).

Methods

From the prospective biomarker cohort study START-TKI (NCT05221372), including patients with metastatic EGFR + NSCLC, we collected deep frozen plasma samples at initiation and during osimertinib treatment. Imaging flow cytometry (IFC) was used to determine the concentration of tetraspanin positive EVs and detection of RANKL on EVs. RANKL and OPG levels were measured by enzyme-linked immunosorbent assay (ELISA). Data on demographics, date of NSCLC diagnosis, date of initiation of osimertinib, presence of bone metastases and SREs were collected. Primary endpoint was the relation between (RANKL+) EV levels and bone metastases.

Results

Forty unique patients with in total 50 plasma samples (45% at initiation of osimertinib, 55% during osimertinib treatment) were included. Identification of EVs was possible in 38/40 patients, and determination of RANKL and OPG plasma levels in all samples. Of these 40 patients, 25 (63%) had bone metastases at sample collection. Both total EV and RANKL+ EV concentrations were significantly higher in samples at initiation of osimertinib compared to samples during treatment [mean ± standard deviation (SD), 6.3×1012±2.1×1012/mL plasma vs. 3.2×1012±1.9×1012/mL plasma, P≤0.001 for total EV concentrations; and 2.2×1010±9.3×109/mL plasma vs. 1.1×1010±8.0×109/mL plasma, P=0.001 for RANKL+ EVs]. Patients without a SRE had a significantly higher concentration of RANKL+ EVs compared to patients with an SRE (mean ± SD, 1.8×1010±1.1×1010/mL plasma vs. 1.1×1010±7.4×109/mL plasma, P=0.02). No association was found between the total EV concentration or RANKL+ EVs, plasma levels of OPG and RANKL and bone metastases.

Conclusions

No association was found between the presence of bone metastases and the total concentration of EVs, RANKL+ EVs, or plasma values of RANKL and OPG. In patients without SREs the concentration of RANKL+ EVs was significantly increased. Both the total EV and RANKL+ EV concentrations significantly decreased during osimertinib treatment. This opens new perspectives for the role of (RANKL+) EVs as prognostic biomarkers for EGFR + NSCLC disease progression and response to therapy.

Lung Adenocarcinoma With Bone Metastases: Clinicogenomic Profiling and Insights Into Prognostic Factors

IntroductionLung adenocarcinoma is the leading cause of cancer-related mortality worldwide. Understanding the clinicopathological profiles and genomic drivers of its metastatic patterns is a crucial step for risk stratification. Herein, we investigated the clinicogenomic features of bone metastases in lung adenocarcinoma and their prognostic value.MethodsA retrospective cohort study with a total of 4064 patients with various metastatic patterns of lung adenocarcinoma were included, obtaining relevant clinical data and genomic profiles. Patients were categorized based on the presence or absence of bone metastases. A comparative analysis of both groups in terms of demographics, disease status, somatic mutations, and microsatellite instability was carried out. Significantly different variables were tested for their association with bone metastases. Cox regression analyses were utilized to identify independent survival prognostic variables in the bone metastases sub-cohort.ResultsGender, concomitant metastases (to adrenal gland, nervous system, lymph nodes, liver, lung, mediastinum, pleura, and skin), and aberrations in TP53, EGFR, KEAP1, and MYC were associated with bone metastases in lung adenocarcinoma. Survival analyses within the bone metastases sub-cohort have illustrated the following variables to possess poor prognostic signature including age > 75, female gender, White ethnicity, distant metastases (adrenal gland, central nervous system, intra-abdominal, and liver), EGFR (wild type), KEAP1 (mutant), MYC (mutant), KRAS (mutant), and SMARCA4 (mutant).ConclusionKey clinical and genomic factors associated with lung adenocarcinoma bone metastases have been highlighted, providing exploratory insights into high-risk individuals. Future studies should be directed to validate these prognostic variables in larger, more diverse cohorts to enhance generalizability.

New insights into non-small cell lung cancer bone metastasis: mechanisms and therapies

Bone metastasis is a common cause of death in patients with non-small cell lung cancer (NSCLC), with approximately 30-40% of NSCLC patients eventually developing bone metastases. Bone metastasis, especially the occurrence of skeletal-related events (SREs), significantly reduces overall survival (OS) and quality of life (QoL) in patients. Although bone-targeting agents (BTAs) have been shown to reduce SREs and improve QoL in NSCLC patients with bone metastases, the prognosis for these patients remains poor. Understanding the underlying molecular pathways of bone metastasis is crucial for the development of novel therapeutic approaches. Bone metastasis is a complex, multistep process that involves interactions between tumor cells and the bone microenvironment. The bone microenvironment provides a fertile soil for tumor cells, and crosstalk among various signaling pathways and secreted factors also plays a role in regulating the occurrence and progression of bone metastasis in NSCLC. In this article, we provide a comprehensive review of the process, regulatory mechanisms, and clinical treatment in NSCLC bone metastasis, with the hope of assisting with clinical treatment.

Bone marrow adipocytes and lung cancer bone metastasis: unraveling the role of adipokines in the tumor microenvironment

Bone is a common site of metastasis for lung cancer. The "seed and soil" hypothesis suggests that the bone marrow microenvironment ("soil") may provide a conducive survival environment for metastasizing tumor cells ("seeds"). The bone marrow microenvironment, comprising a complex array of cells, includes bone marrow adipocytes (BMAs), which constitute about 70% of the adult bone marrow volume and may play a significant role in tumor bone metastasis. BMAs can directly provide energy for tumor cells, promoting their proliferation and migration. Furthermore, BMAs participate in the tumor microenvironment's osteogenesis regulation, osteoclast(OC) regulation, and immune response through the secretion of adipokines, cytokines, and inflammatory factors. However, the precise mechanisms of BMAs in lung cancer bone metastasis remain largely unclear. This review primarily explores the role of BMAs and their secreted adipokines (leptin, adiponectin, Nesfatin-1, Resistin, chemerin, visfatin) in lung cancer bone metastasis, aiming to provide new insights into the mechanisms and clinical treatment of lung cancer bone metastasis.