{"doi":"10.1002/ctm2.1662","title":"Inhibition of autophagy antagonizes breast cancer brain metastogenesis and augments the anticancer activity of lapatinib","abstract":"Dear Editor, Brain metastases are the most prevalent adult central nervous system tumours with 20%−30% of cases resulting from breast cancer patients, particularly those with triple-negative (ER-, PR-, HER2 unamplified) and HER2 amplified disease. The prognosis for individuals with brain metastases from breast cancer continues to be extremely unfavourable, with a mere 20% achieving 5-year survival.1 New targeted approaches are clearly needed to improve outcomes for this patient population. Autophagy is a lysosomal catabolic process that controls the turnover of organelles and selected proteins.2, 3 During metastogenesis, tumour cells face diverse stressors including nutrient and oxygen deprivation and may activate autophagy to avert bioenergetic failure and sustain their survival.4 We investigated the role of autophagy competence as a regulator of the brain metastogenic potential of breast cancer cells and assessed inhibition of autophagy as a clinically actionable approach to prevent and treat brain metastases. We first used the well characterized breast cancer cell line MDA-MB-231 and its brain-targeted metastatic variants (231-BR and 231-BR-HER2) to investigate differences in energy metabolism in cells that preferentially metastasize to the brain (Figure S1A,B).5-7 Global metabolic profiling identified the nucleotide biosynthesis super pathway as one of the most significantly altered between parental and brain metastatic breast cancer cells (Figure 1A,B). Quantification of individual nucleotide pathway components revealed that adenosine 5′-monophosphate (AMP) and adenosine 5′-disphosphate (ADP_ levels were remarkably higher, while ATP levels were significantly lower in the brain metastatic variants (Figure 1C). Notably, differences in ATP production between other types of primary tumours and metastases were also recently reported.8 We detected diminished levels of the TCA cycle intermediates citrate, cis-aconitate, and malate (Figure S2), lower pyrophosphate and higher phosphate levels (Figure S3), lower ATP levels (Figure 1D) and significantly higher levels of FAD+ and NADH in brain metastatic cells (Figure S4). To determine if brain metastatic cells utilize autophagy to compensate for their altered metabolic profiles, we assessed the levels of phospho-AMPK and its downstream target phospho-ULK1. Both were elevated in the brain-targeted variants (Figure 1E). Additionally, brain metastatic cells exhibited decreased p62 levels and increased LC3B expression (Figure 1F), and increased numbers of autophagosomes (Figure 1G) and LC3B puncta (Figure 1H), which collectively support enhanced basal autophagy. We next genetically impaired the essential autophagy gene ATG7 in 231-BR-HER2 cells using shRNA to investigate the role of autophagy during brain metastogenesis in mice (Figure 2A). Representative brains were collected from mice on day 23 and whole brain fluorescence imaging was performed to quantify brain metastases. Metastatic burden was dramatically reduced in mouse brains injected with cells with stably silenced ATG7 (Figure 2B). To evaluate how autophagy competence impacts the number and size of breast cancer brain metastases, brains from each group were serially cut and stained with H&E and subjected to image-based quantification. Notably, the number of both micrometastases (<50 μm2) and large metastases (>50 μm2) were significantly reduced in the ATG7 shRNA injected mice (Figures 2C and S5). The remaining mice were monitored over 100 days to verify the long-term effect of ATG7 silencing on autophagic inhibition and animal survival. Consistent with their decreased brain metastatic burden, mice injected with 231-BR-HER2 ATG7 shRNA cells displayed elevated p62 levels (Figure 2D) and experienced considerably increased overall survival (Figure 2E). The factors that limit the efficacy of the FDA approved HER2/EGFR inhibitor lapatinib against breast cancer brain metastases have yet to be fully elucidated, but its effects on HER2","journal":"Clinical and Translational Medicine","year":2024,"id":463980,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":5,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9553,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":384849,"name":"Claudia M. Espitia","orcid":"0000-0002-4109-2584","position":1,"is_corresponding":false},{"id":1295069,"name":"Maria Janina Carrera Espinoza","orcid":null,"position":2,"is_corresponding":false},{"id":907342,"name":"Trace M. Jones","orcid":"0000-0001-6198-2712","position":3,"is_corresponding":false},{"id":1295070,"name":"Madison E. Gamble","orcid":null,"position":4,"is_corresponding":false},{"id":1295071,"name":"S. Sureshkumar","orcid":null,"position":5,"is_corresponding":false},{"id":878940,"name":"Mengyang Chang","orcid":"0000-0001-9679-8616","position":6,"is_corresponding":false},{"id":332006,"name":"Wei Wang","orcid":"0000-0001-6043-0860","position":7,"is_corresponding":false},{"id":384851,"name":"Jennifer S. Carew","orcid":"0000-0002-8578-8292","position":8,"is_corresponding":false},{"id":384852,"name":"Steffan T. Nawrocki","orcid":"0000-0001-8767-3969","position":0,"is_corresponding":true}],"reference_count":11,"raw_metadata":null,"created_at":"2026-07-19T02:04:37.468651Z","pmid":"38658768","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}