Triple-negative breast cancer (TNBC) has limited therapeutic options, is highly metastatic and characterized by early recurrence. Lipid metabolism is generally deregulated in TNBC and might reveal vulnerabilities to be targeted or used as biomarkers with clinical value. Ferroptosis is a type of cell death caused by iron-dependent lipid peroxidation which is facilitated by the presence of polyunsaturated fatty acids (PUFA). Here we identify fatty acid desaturases 1 and 2 (FADS1/2), which are responsible for PUFA biosynthesis, to be highly expressed in a subset of TNBC with a poorer prognosis. Lipidomic analysis, coupled with functional metabolic assays, showed that FADS1/2 high-expressing TNBC are susceptible to ferroptosis-inducing agents and that targeting FADS1/2 by both genetic interference and pharmacological approach renders those tumors ferroptosis-resistant while unbalancing PUFA/MUFA ratio by the supplementation of exogenous PUFA sensitizes resistant tumors to ferroptosis induction. Last, inhibiting lipid droplet (LD) formation and turnover suppresses the buffering capacity of LD and potentiates iron-dependent cell death. These findings have been validated in vitro and in vivo in mouse- and human-derived clinically relevant models and in a retrospective cohort of TNBC patients.

Extracellular matrix (ECM) is a major component of the tumor environment, promoting the establishment of a pro-invasive behavior. Such environment is supported by both tumor- and stromal-derived metabolites, particularly lactate. In prostate cancer (PCa), cancer-associated fibroblasts (CAFs) are major contributors of secreted lactate, able to impact on metabolic and transcriptional regulation in cancer cells. Here, we describe a mechanism by which CAF-secreted lactate promotes in PCa cells the expression of genes coding for the collagen family. Lactate-exploiting PCa cells rely on increased α-ketoglutarate (α-KG) which activates the α-KG-dependent collagen prolyl-4-hydroxylase (P4HA1) to support collagen hydroxylation. De novo synthetized collagen plays a signaling role by activating discoidin domain receptor 1 (DDR1), supporting stem-like and invasive features of PCa cells. Inhibition of lactate-induced collagen hydroxylation and DDR1 activation reduces the metastatic colonization of PCa cells. Overall, these results provide a new understanding of the link between collagen remodeling/signaling and the nutrient environment exploited by PCa.

Targeting aromatase deprives ER ⁺ breast cancers of estrogens and is an effective therapeutic approach for these tumors. However, drug resistance is an unmet clinical need. Lipidomic analysis of long-term estrogen-deprived (LTED) ER ⁺ breast cancer cells, a model of aromatase inhibitor resistance, revealed enhanced intracellular lipid storage. Functional metabolic analysis showed that lipid droplets together with peroxisomes, which we showed to be enriched and active in the LTED cells, controlled redox homeostasis and conferred metabolic adaptability to the resistant tumors. This reprogramming was controlled by acetyl-CoA-carboxylase-1 (ACC1), whose targeting selectively impaired LTED survival. However, the addition of branched- and very long–chain fatty acids reverted ACC1 inhibition, a process that was mediated by peroxisome function and redox homeostasis. The therapeutic relevance of these findings was validated in aromatase inhibitor–treated patient-derived samples. Last, targeting ACC1 reduced tumor growth of resistant patient-derived xenografts, thus identifying a targetable hub to combat the acquisition of estrogen independence in ER ⁺ breast cancers.

The majority of breast cancers express the estrogen receptor (ER) and are dependent on estrogen for their growth and survival. Endocrine therapy (ET) is the standard of care for these tumors. However, a superior outcome is achieved in a subset of ER positive (ER⁺)/human epidermal growth factor receptor 2 negative (HER2⁻) metastatic breast cancer patients when ET is administrated in combination with a cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitor, such as palbociclib. Moreover, CDK4/6 inhibitors are currently being tested in ER⁺/HER2⁺ breast cancer and reported encouraging results. Despite the clinical advances of a combinatorial therapy using ET plus CDK4/6 inhibitors, potential limitations (i.e., resistance) could emerge and the metabolic adaptations underlying such resistance warrant further elucidation. Here we investigate the glucose-dependent catabolism in a series of isogenic ER⁺ breast cancer cell lines sensitive to palbociclib and in their derivatives with acquired resistance to the drug. Importantly, ER⁺/HER2⁻ and ER⁺/HER2⁺ cell lines show a different degree of glucose dependency. While ER⁺/HER2⁻ breast cancer cells are characterized by enhanced aerobic glycolysis at the time of palbociclib sensitivity, ER⁺/HER2⁺ cells enhance their glycolytic catabolism at resistance. This metabolic phenotype was shown to have prognostic value and was targeted with multiple approaches offering a series of potential scenarios that could be of clinical relevance.

Although there is broad information about the influence of spurious hemolysis on several laboratory tests, less is known on the bias produced on D-dimer testing. Four different pools were obtained from primary blood tubes, and each of them was divided into four aliquots. The first nonhemolyzed was centrifuged, the plasma was separated and then tested for hemolysis index and D-dimer. The second (hemolyzed aliquot A), third (hemolyzed aliquot B) and fourth (hemolyzed aliquot C) aliquots were mechanically hemolyzed by aspirating whole blood one, two and three times through a fine needle. The plasma was then separated and tested for hemolysis index and D-dimer. D-dimer was quantified by HemosIL AcuStar D-dimer and HemosIL D-dimer HS for ACL TOP. Undetectable hemolysis was present in aliquot nonhemolyzed (<0.5 g/l), whereas the concentration of cell-free hemoglobin significantly increased from hemolyzed aliquot A (5.5–7.0 g/l hemoglobin) to hemolyzed aliquot B (11.5 and 15.0 g/l hemoglobin) and hemolyzed aliquot C (20–22 g/l hemoglobin). The plasma concentration of D-dimer decreased from aliquots nonhemolyzed to hemolyzed aliquot C, achieving clinical significance fromhemolyzed aliquot A and hemolyzed aliquot B when measured with D-dimer HS for ACL TOP and AcuStar D-dimer, respectively. The decrease with AcuStar D-dimer was −5 ± 3% in hemolyzed aliquot A, −7 ± 3% in hemolyzed aliquot B, and −9 ± 3% in hemolyzed aliquot C, whereas the decrease with D-dimer HS for ACL TOP was −5 ± 3% in hemolyzed aliquot A, −8 ± 3% in hemolyzed aliquot B and −9 ± 3% in hemolyzed aliquot C. The similar trend towards decreasing values observed when measuring D-dimer with chemiluminescent and turbidimetric immmunoassays on four heterogeneous plasma pools suggest that the hemolysis interference is more likely to be biological than analytical. The modest bias observed in samples with frank hemolysis (i.e. cell-free hemoglobin of 11.5 g/l) confirms that both methods are robust against this type of interference, so that test results might be released in the majority of mildly hemolyzed samples.