bims-merabr 2025-03-23 papers

Free Radic Biol Med. 2025 Mar 13. pii: S0891-5849(25)00169-8. [Epub ahead of print]232 330-339

YAP-mediated DDX3X confers resistance to ferroptosis in breast cancer cells by reducing lipid peroxidation.

Jia-Zih Dai, Wen-Jing Hsu, Mei-Hsiang Lin, Pei-Wei Shueng, Chi-Ching Lee, Ching-Chieh Yang, Cheng-Wei Lin.

Metabolic shifts in cancer cells were found to participate in tumorigenesis, especially driving chemotherapeutic resistance. Ferroptosis is a newly discovered form of cell death induced by excessive accumulations of iron and lipid peroxidation. Susceptibility to ferroptosis can be intrinsically regulated by various cellular metabolic pathways. Therefore, inducing ferroptosis might be a promising anticancer therapeutic strategy. DEAD-box helicase 3 X-linked (DDX3X), a critical modulator of RNA metabolism, was identified as an oncogene in breast cancer and also participates in cancer metabolism and chemotherapeutic resistance. However, the molecular regulation of the association between DDX3X and ferroptosis is largely unknown. Herein, we investigated the correlation between resistance to ferroptosis and DDX3X expression in breast cancer cells. We found that elevation of DDX3X was associated with increased resistance to a ferroptosis inducer in breast cancer cells, and manipulating DDX3X expression regulated the sensitivity to the ferroptosis inducer. Importantly, DDX3X upregulated expression of the anti-ferroptotic enzyme glutathione peroxidase 4 (GPX4) gene to confer ferroptosis resistance in breast cancer cells. Moreover, DDX3X was transcriptionally upregulated by the yes-associated protein (YAP). Knockdown of YAP downregulated DDX3X mRNA expression and facilitated lipid peroxidation, but that were restored in the presence of DDX3X. Clinically, coexpression of DDX3X and YAP was found in a variety of malignancy, and their elevation conferred poor survival prognosis in patients with breast cancer. Together, our findings reveal the crucial role of DDX3X in sensitivity to ferroptosis and underscore its potential as a diagnostic marker and therapeutic target. DDX3X renders resistance to ferroptosis and plays a role in mitigating lipid peroxidation, paving the way for therapeutic vulnerability via targeting cancer metabolism.

Keywords: Breast cancer; DEAD-box helicase 3 X-linked; Ferroptosis; Glutathione peroxidase 4; Yes-associated protein

DOI: https://doi.org/10.1016/j.freeradbiomed.2025.03.019

Breast Cancer Res Treat. 2025 Mar 17.

FGFR4 in endocrine resistance: overexpression and estrogen regulation without direct causative role.

Kai Ding, Lyuqin Chen, Kevin M Levine, Matthew J Sikora, Nilgun Tasdemir, David Dabbs, Rachel Jankowitz, Rachel Hazan, Osama Shah, Jenny Atkinson, Adrian V Lee, Steffi Oesterreich.

PURPOSE: Endocrine therapy resistance is the major challenge of managing patients with estrogen receptor positive (ER+) breast cancer. We previously reported frequent overexpression of FGFR4 in endocrine-resistant cell lines and breast cancers that recurred and metastasized following endocrine therapy, suggesting FGFR4 as a potential driver of endocrine resistance. In this study, we investigated the role of FGFR4 in mediating endocrine resistance and explored the therapeutic potential of targeting FGFR4 in advanced breast cancer.
METHODS: A gene expression signature of FGFR4 activity was examined in ER+breast cancer pre- and post-neoadjuvant endocrine therapy and the association between FGFR4 expression and patient survival was examined. A correlation analysis was used to uncover potential regulators of FGFR4 overexpression. To investigate if FGFR4 is necessary to drive endocrine resistance, we tested response to FGFR4 inhibition in long-term estrogen-deprived (LTED) cells and their paired parental cells. Doxycycline inducible FGFR4 overexpression and knockdown cell models were generated to examine if FGFR4 was sufficient to confer endocrine resistance. Finally, we examined response to FGFR4 monotherapy or combination therapy with fulvestrant in breast cancer cell lines to explore the potential of FGFR4 targeted therapy for advanced breast cancer and assessed the importance of PAM50 subtype in response to FGFR4 inhibition.
RESULTS: A FGFR4 activity gene signature was significantly upregulated post-neoadjuvant aromatase inhibitor treatment, and high FGFR4 expression predicted poorer survival in patients with ER+breast cancer. Gene expression association analysis using TCGA, METABRIC, and SCAN-B datasets uncovered ER as the most significant gene negatively correlated with FGFR4 expression. ER negatively regulates FGFR4 expression at both the mRNA and protein level across multiple ER+breast cancer cell lines. Despite robust overexpression of FGFR4, LTED cells did not show enhanced responses to FGFR4 inhibition compared to parental cells. Similarly, FGFR4 overexpression and knockdown did not substantially alter response to endocrine treatment in ER+cell lines, nor did FGFR4 and fulvestrant combination treatment show synergistic effects. The HER2-like subtype of breast cancer showed elevated expression of FGFR4 and an increased response to FGFR4 inhibition relative to other breast cancer subtypes.
CONCLUSIONS: Despite ER-mediated upregulation of FGFR4 post-endocrine therapy, our study does not support a general role of FGFR4 in mediating endocrine resistance in ER+breast cancer. The significant upregulation of FGFR4 expression in treatment-resistant clinical samples and models following endocrine therapy does not necessarily establish a causal link between the gene and treatment response. Our data suggest that specific genomic backgrounds such as HER2 expression may be required for FGFR4 function in breast cancer and should be further explored.

Keywords: Breast cancer; Endocrine resistance; Estrogen receptor; FGFR4; HER2

DOI: https://doi.org/10.1007/s10549-025-07666-x

J Biomed Sci. 2025 Mar 17. 32(1): 36

Metformin sensitizes triple-negative breast cancer to histone deacetylase inhibitors by targeting FGFR4.

Zhangyuan Gu, Fugui Ye, Hong Luo, Xiaoguang Li, Yue Gong, Shiqi Mao, Xiaoqing Jia, Xiangchen Han, Boyue Han, Yun Fu, Xiaolin Cheng, Jiejing Li, Zhiming Shao, Peizhen Wen, Xin Hu, Zhigang Zhuang.

BACKGROUND: Triple-negative breast cancer (TNBC) is characterized by high malignancy, strong invasiveness, and a propensity for distant metastasis, leading to poor prognosis and relatively limited treatment options. Metformin, as a first-line oral hypoglycemic agent, has garnered widespread research interest in recent years due to its potential in cancer prevention and treatment. However, its efficacy varies significantly across different tumor types. Histone deacetylase inhibitors (HDACi), such as SAHA, have demonstrated antitumor activity, but TNBC responds poorly to HDACi monotherapy, possibly due to feedback activation of the JAK-STAT pathway. Exploring the synergistic potential and underlying mechanisms of combining metformin with HDACi in TNBC treatment is crucial.
METHODS: We predicted the synergistic effects of metformin and SAHA in TNBC using multiple computational methods (CMap, DTsyn, and DrugComb). We also developed a cancer-specific compound mimic library (CDTSL) and applied a three-step strategy to identify genes fitting the "metformin sensitization" model. Subsequently, we evaluated the synergistic effects of metformin and SAHA in TNBC cell lines through cell proliferation, colony formation, and apoptosis assays. Furthermore, we investigated the molecular mechanisms of the combined treatment using techniques such as transcriptome sequencing, chromatin immunoprecipitation (ChIP), Western blotting, and measurement of extracellular acidification rate (ECAR). Additionally, we assessed the in vivo antitumor effects of the combined therapy in a nude mouse subcutaneous xenograft model.
RESULTS: CMap, DTsyn, and DrugComb all predicted the synergistic effects of SAHA and metformin in TNBC. The screening results revealed that HDAC10 played a key role in metformin sensitization. We found that the combination of metformin and SAHA exhibited synergistic antitumor effects (combination index CI < 0.9) in TNBC cell lines. Mechanistically, metformin inhibited histone acetylation on FGFR4, thereby blocking the feedback activation of FGFR4 downstream pathways induced by SAHA. Furthermore, metformin interfered with the glycolysis process induced by SAHA, altering the metabolic reprogramming of tumor cells. In in vivo experiments, the combined treatment of metformin and SAHA significantly inhibited the growth of subcutaneous tumors in nude mice.
CONCLUSIONS: Metformin enhances the sensitivity of TNBC to HDAC inhibitors by blocking the FGFR4 pathway and interfering with metabolic reprogramming. When used in combination with SAHA, metformin exhibits synergistic antitumor effects. Our study provides a theoretical basis for the combined application of HDAC inhibitors and metformin, potentially offering a new strategy for the treatment of TNBC.

Keywords: Drug synergism; Histone deacetylase inhibitors; Metformin; Triple-negative breast neoplasms

DOI: https://doi.org/10.1186/s12929-025-01129-7

Sci Adv. 2025 Mar 21. 11(12): eads9182

A metabolic shift to the serine pathway induced by lipids fosters epigenetic reprogramming in nontransformed breast cells.

Lipid metabolism and the serine, one-carbon, glycine (SOG) and methionine pathways are independently and significantly correlated with estrogen receptor-negative breast cancer (ERneg BC). Here, we propose a link between lipid metabolism and ERneg BC through phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in the de novo serine pathway. We demonstrate that the metabolism of the paradigmatic medium-chain fatty acid octanoic acid leads to a metabolic shift toward the SOG and methionine pathways. PHGDH plays a role in both the forward direction, contributing to the production of S-adenosylmethionine, and the reverse direction, generating the oncometabolite 2-hydroxyglutarate, leading to epigenomic reprogramming and phenotypic plasticity. The methionine cycle is closely linked to the transsulfuration pathway. Consequently, we observe that the shift increases the antioxidant glutathione, which mitigates reactive oxygen species (ROS), enabling survival of a subset of cells that have undergone DNA damage. These metabolic changes contribute to several hallmarks of cancer.

DOI: https://doi.org/10.1126/sciadv.ads9182