bims-merabr 2024-10-27 papers

Discov Oncol. 2024 Oct 23. 15(1): 584

Loss of miR-634 contributes to the formation FOXA1-positive triple negative breast cancer subtype.

BACKGROUND: Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer, lacks targeted therapies, posing a substantial challenge for treatment. Therefore, investigating its pathogenesis is a crucial research focus. FOXA1 and miR-634 are involved in tumorigenesis. However, the molecular mechanisms underlying the aberrant upregulation of FOXA1 expression in TNBC remain unclear. Therefore, we explore the role of miR-634 in the FOXA1-positive TNBC subtype.
METHODS: Quantitative reverse transcription polymerase chain reaction was used to detect miR-634 expression in breast cancer tissues and cell lines. Aberrantly activated signaling pathways and related genes in TNBC were analyzed using The Cancer Genome Atlas. The potential target of miR-634 was predicted by TargetScan, the TNBC cell proliferation rate was detected using an MTT assay, the in vitro metastatic capacity was determined by transwell assay and the cell cycle distribution was tested using flow cytometry. Western blotting was performed to measure the expression of proteins involved in the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway.
RESULTS: The expression of miR-634 was significantly down-regulated in both TNBC tissues and cells, compared with adjacent non-cancerous tissues and MCF10A, respectively. Ectopic expression of miR-634 inhibits breast cancer cell proliferation and in vitro metastasis. The TCGA-based expression profile analysis of TNBC revealed that aberrantly activated PI3K/AKT signaling may contribute to its malignant phenotype. FOXA1, the top hit of aberrantly upregulated genes in TNBC, was a direct target of miR-643. Moreover, forced expression of miR-643 drastically suppressed FOXA1 expression by the inactivation PI3K/AKT signaling.
CONCLUSION: MiR-634 suppresses FOXA1 to inhibit the proliferation and metastasis of TNBC cells by inactivating the PI3K/AKT signaling pathway.

DOI: https://doi.org/10.1007/s12672-024-01472-5

Cell Metab. 2024 Oct 18. pii: S1550-4131(24)00395-4. [Epub ahead of print]

Adipocyte-derived glutathione promotes obesity-related breast cancer by regulating the SCARB2-ARF1-mTORC1 complex.

Chenxi Zhao, Tingting Zhang, Si-Tu Xue, Peitao Zhang, Feng Wang, Yunxuan Li, Ying Liu, Luyao Zhao, Jie Wu, Yechao Yan, Xiaoyun Mao, Yuping Chen, Jian Yuan, Zhuorong Li, Ke Li.

Obesity is a major risk factor for poor breast cancer outcomes, but the impact of obesity-induced tumor microenvironment (TME) metabolites on breast cancer growth and metastasis remains unclear. Here, we performed TME metabolomic analysis in high-fat diet (HFD) mouse models and found that glutathione (GSH) levels were elevated in the TME of obesity-accelerated breast cancer. The deletion of glutamate-cysteine ligase catalytic subunit (GCLC), the rate-limiting enzyme in GSH biosynthesis, in adipocytes but not tumor cells reduced obesity-related tumor progression. Mechanistically, we identified that GSH entered tumor cells and directly bound to lysosomal integral membrane protein-2 (scavenger receptor class B, member 2 [SCARB2]), interfering with the interaction between its N and C termini. This, in turn, recruited mTORC1 to lysosomes through ARF1, leading to the activation of mTOR signaling. Overall, we demonstrated that GSH links obesity and breast cancer progression by acting as an activator of mTOR signaling. Targeting the GSH/SCARB2/mTOR axis could benefit breast cancer patients with obesity.

Keywords: ARF1; GSH; SCARB2; adipocyte; breast cancer; glutathione; lysosomal integral membrane protein-2; mTORC1; mammalian target of rapamycin complex 1; obesity

DOI: https://doi.org/10.1016/j.cmet.2024.09.013

Genes Genet Syst. 2024 Oct 18.

FOXM1 derived from Triple negative breast cancer exosomes promotes cancer progression by activating IDO1 transcription in macrophages to suppress ferroptosis and induce M2 polarization of Tumor-associated macrophages.

Tielin Wang, Yan Zhang, Hong Liu, Jian Wu.

To explore the oncogenic mechanism of FOXM1 in the tumor microenvironment (TME) regarding triple negative breast cancer (TNBC) promotion. The mRNA and protein levels of target genes in TNBC cells and their exosomes were detected by RT-qPCR and western blot. Co-culture models of TNBC cells and THP-1/M0 macrophages was established to detect the impact of co-culture on FOXM1 expression and macrophage polarization direction. The bioinformatics website was used to predict the binding sites between the FOXM1 and IDO1 promoter, which were further validated using dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay. Finally, after erastin-induced ferroptosis, Cell Counting Kit-8 (CCK-8), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and other experiments were conducted to investigate whether the FOXM1/IDO1 axis regulates M2 macrophage polarization through ferroptosis. It was found that FOXM1 was highly expressed in exosomes derived from TNBC cells, and TNBC cells upregulated FOXM1 expression in THP-1 cells through exosomes to promote M2 macrophage polarization. Furthermore, FOXM1 upregulated IDO1 in M2-type TAMs by regulating transcription. Lastly, FOXM1/IDO1 inhibited ferroptosis, promoting M2 macrophage polarization, thereby advancing TNBC progression. In conclusions, FOXM1 derived from TNBC cell-derived exosomes activated IDO1 transcription in TAMs to inhibit ferroptosis, promoting TAMs' M2 polarization and exerting carcinogenic effects.

Keywords: FOXM1; IDO1; M2 macrophage polarization; TNBC; exosomes

DOI: https://doi.org/10.1266/ggs.24-00079

Cell Oncol (Dordr). 2024 Oct 21.

SUMOylation regulates the aggressiveness of breast cancer-associated fibroblasts.

Angelica Martínez-López, Guiomar Infante, Marina Mendiburu-Eliçabe, Andrés Machuca, Olga M Antón, Mónica González-Fernández, José L Luque-García, Robert B Clarke, Sonia Castillo-Lluva.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are the most abundant stromal cellular component in the tumor microenvironment (TME). CAFs contribute to tumorigenesis and have been proposed as targets for anticancer therapies. Similarly, dysregulation of SUMO machinery components can disrupt the balance of SUMOylation, contributing to tumorigenesis and drug resistance in various cancers, including breast cancer. We explored the role of SUMOylation in breast CAFs and evaluated its potential as a therapeutic strategy in breast cancer.
METHODS: We used pharmacological and genetic approaches to analyse the functional crosstalk between breast tumor cells and CAFs. We treated breast CAFs with the SUMO1 inhibitor ginkgolic acid (GA) at two different concentrations and conditioned media was used to analyse the proliferation, migration, and invasion of breast cancer cells from different molecular subtypes. Additionally, we performed quantitative proteomics (SILAC) to study the differential signalling pathways expressed in CAFs treated with low or high concentrations of GA. We confirmed these results both in vitro and in vivo. Moreover, we used samples from metastatic breast cancer patients to evaluate the use of GA as a therapeutic strategy.
RESULTS: Inhibition of SUMOylation with ginkgolic acid (GA) induces death in breast cancer cells but does not affect the viability of CAFs, indicating that CAFs are resistant to this therapy. While CAF viability is unaffected, CAF-conditioned media (CM) is altered by GA, impacting tumor cell behaviour in different ways depending on the overall degree to which SUMO1-SUMOylated proteins are dysregulated. Breast cancer cell lines exhibited a concentration-dependent response to conditioned media (CM) from CAFs. At a low concentration of GA (10 µM), there was an increase in proliferation, migration and invasion of breast cancer cells. However, at a higher concentration of GA (30 µM), these processes were inhibited. Similarly, analysis of tumor development revealed that at 10 µM of GA, the tumors were heavier and there was a greater degree of metastasis compared to the tumors treated with the higher concentration of GA (30 µM). Moreover, some of these effects could be explained by an alteration in the activity of the GTPase Rac1 and the activation of the AKT signalling pathway. The results obtained using SILAC suggest that different concentrations of GA affected cellular processes differentially, possibly influencing the secretome of CAFs. Treatment of metastatic breast cancer with GA demonstrated the use of SUMOylation inhibition as an alternative therapeutic strategy.
CONCLUSION: The study highlights the importance of SUMOylation in the tumor microenvironment, specifically in cancer-associated fibroblasts (CAFs). Targeting SUMOylation in CAFs affects their signalling pathways and secretome in a concentration-dependent manner, regulating the protumorigenic properties of CAFs.

Keywords: Breast cancer; CAFs; Ginkgolic acid; SILAC; SUMOylation

DOI: https://doi.org/10.1007/s13402-024-01005-w

Int Immunopharmacol. 2024 Oct 18. pii: S1567-5769(24)01909-X. [Epub ahead of print]143(Pt 2): 113387

Tumor-associated macrophages induce epithelial-mesenchymal transition and promote lung metastasis in breast cancer by activating the IL-6/STAT3/TGM2 axis.

Yana Qi, Ranran Li, Mingyong Han.

Breast cancer is one of the most common tumors in the world and metastasis is the major cause of tumor-related death. Tumor-associated macrophages (TAMs) are a major component of the tumor microenvironment (TME) and often associated with cancer metastasis. Nevertheless, the mechanism by which TAMs regulate breast cancer metastasis remain unclear. In this study, we found that transglutaminase 2 (TGM2) could serve as a crucial target in the modulation of TAMs-induced epithelial-mesenchymal transition (EMT) and invasion of breast cancer cells. Further analysis revealed that IL-6 secreted from TAMs, which was capable of inducing TGM2 expression through the activation of the JAK/STAT3 signaling pathway. Subsequent luciferase reporter assays demonstrated that STAT3 binds to the TGM2 promoter region, thereby transcriptionally enhancing TGM2 expression. In conclusion, our current research has identified the IL-6/STAT3/TGM2 axis as a pivotal regulator in breast tumorigenesis caused by TAMs, presenting a novel target for the treatment of breast cancer.

Keywords: Breast cancer; Epithelial-mesenchymal transition; Interleukin-6; Metastasis; TGM2; Tumor-associated macrophages

DOI: https://doi.org/10.1016/j.intimp.2024.113387

EMBO Mol Med. 2024 Oct 21.

Breast cancer secretes anti-ferroptotic MUFAs and depends on selenoprotein synthesis for metastasis.

Tobias Ackermann, Engy Shokry, Ruhi Deshmukh, Jayanthi Anand, Laura C A Galbraith, Louise Mitchell, Giovanny Rodriguez-Blanco, Victor H Villar, Britt Amber Sterken, Colin Nixon, Sara Zanivan, Karen Blyth, David Sumpton, Saverio Tardito.

The limited availability of therapeutic options for patients with triple-negative breast cancer (TNBC) contributes to the high rate of metastatic recurrence and poor prognosis. Ferroptosis is a type of cell death caused by iron-dependent lipid peroxidation and counteracted by the antioxidant activity of the selenoprotein GPX4. Here, we show that TNBC cells secrete an anti-ferroptotic factor in the extracellular environment when cultured at high cell densities but are primed to ferroptosis when forming colonies at low density. We found that secretion of the anti-ferroptotic factors, identified as monounsaturated fatty acid (MUFA) containing lipids, and the vulnerability to ferroptosis of single cells depends on the low expression of stearyl-CoA desaturase (SCD) that is proportional to cell density. Finally, we show that the inhibition of Sec-tRNAsec biosynthesis, an essential step for selenoprotein production, causes ferroptosis and impairs the lung seeding of circulating TNBC cells that are no longer protected by the MUFA-rich environment of the primary tumour.

Keywords: Breast Cancer; Ferroptosis; Lipid Metabolism; Metastasis; Selenium Metabolism

DOI: https://doi.org/10.1038/s44321-024-00142-x