bims-merabr Biomed News
on Metabolic rewiring in aggressive breast cancer
Issue of 2024–05–19
fourteen papers selected by
Barbara Mensah Sankofi, University of Oklahoma Health Sciences Center
  1. Genome-wide association analyses of breast cancer in women of African ancestry identify new susceptibility loci and improve risk prediction.
  2. CRISPR-Cas13d screens identify KILR, a breast cancer risk-associated lncRNA that regulates DNA replication and repair.
  3. Pyrotinib is effective in both trastuzumab-sensitive and primary resistant HER2-positive breast tumors.
  4. Type II Interleukin-4 Receptor Activation in Basal Breast Cancer Cells Promotes Tumor Progression via Metabolic and Epigenetic Modulation.
  5. Isolation and Characterization of a Novel Mammary Adenocarcinoma, MCa-P1362, with Hormone Receptor Expression, Human Epidermal Growth Factor Receptor 2 Positivity, and Enrichment in Cancer and Mesenchymal Stem Cells.
  6. RPGRIP1L as a new biomarker for prognosis and tumor immune of breast cancer.
  7. Continuous TNF-α exposure in mammary epithelial cells promotes cancer phenotype acquisition via EGFR/TNFR2 activation.
  8. LINC02535 + miR-30a-5p combination enhances proliferation and inhibits apoptosis in metastatic breast Cancer cells.
  9. D-arabinose induces cell cycle arrest by promoting autophagy via p38 MAPK signaling pathway in breast cancer.
  10. Hypomethylation of ATP1A1 Is Associated with Poor Prognosis and Cancer Progression in Triple-Negative Breast Cancer.
  11. Chemoresistance to additive PARP/PI3K dual inhibition in triple-negative breast cancer cell lines is associated with adaptive stem cell-like prevalence.
  12. FGFR2-triggered autophagy and activation of Nrf-2 reduce breast cancer cell response to anti-ER drugs.
  13. Extracellular matrix marker LAMC2 targets ZEB1 to promote TNBC malignancy via up-regulating CD44/STAT3 signaling pathway.
  14. Insulin Resistance Increases TNBC Aggressiveness and Brain Metastasis via Adipocyte-derived Exosomes.
  1. Nat Genet. 2024 May;56(5): 819-826
    Genome-wide association analyses of breast cancer in women of African ancestry identify new susceptibility loci and improve risk prediction.
    Guochong Jia, Jie Ping, Xingyi Guo, Yaohua Yang, Ran Tao, Bingshan Li, Stefan Ambs, Mollie E Barnard, Yu Chen, Montserrat Garcia-Closas, Jian Gu, Jennifer J Hu, Dezheng Huo, Esther M John, Christopher I Li, James L Li, Katherine L Nathanson, Barbara Nemesure, Olufunmilayo I Olopade, Tuya Pal, Michael F Press, Maureen Sanderson, Dale P Sandler, Xiao-Ou Shu, Melissa A Troester, Song Yao, Prisca O Adejumo, Thomas Ahearn, Abenaa M Brewster, Anselm J M Hennis, Timothy Makumbi, Paul Ndom, Katie M O'Brien, Andrew F Olshan, Mojisola M Oluwasanu, Sonya Reid, Ebonee N Butler, Maosheng Huang, Atara Ntekim, Huijun Qian, Haoyu Zhang, Christine B Ambrosone, Qiuyin Cai, Jirong Long, Julie R Palmer, Christopher A Haiman, Wei Zheng.
      We performed genome-wide association studies of breast cancer including 18,034 cases and 22,104 controls of African ancestry. Genetic variants at 12 loci were associated with breast cancer risk (P < 5 × 10-8), including associations of a low-frequency missense variant rs61751053 in ARHGEF38 with overall breast cancer (odds ratio (OR) = 1.48) and a common variant rs76664032 at chromosome 2q14.2 with triple-negative breast cancer (TNBC) (OR = 1.30). Approximately 15.4% of cases with TNBC carried six risk alleles in three genome-wide association study-identified TNBC risk variants, with an OR of 4.21 (95% confidence interval = 2.66-7.03) compared with those carrying fewer than two risk alleles. A polygenic risk score (PRS) showed an area under the receiver operating characteristic curve of 0.60 for the prediction of breast cancer risk, which outperformed PRS derived using data from females of European ancestry. Our study markedly increases the population diversity in genetic studies for breast cancer and demonstrates the utility of PRS for risk prediction in females of African ancestry.
    DOI:  https://doi.org/10.1038/s41588-024-01736-4
  2. Mol Cancer. 2024 May 15. 23(1): 101
    CRISPR-Cas13d screens identify KILR, a breast cancer risk-associated lncRNA that regulates DNA replication and repair.
    Lu Wang, Mainá Bitar, Xue Lu, Sebastien Jacquelin, Sneha Nair, Haran Sivakumaran, Kristine M Hillman, Susanne Kaufmann, Rebekah Ziegman, Francesco Casciello, Harsha Gowda, Joseph Rosenbluh, Stacey L Edwards, Juliet D French.
       BACKGROUND: Long noncoding RNAs (lncRNAs) have surpassed the number of protein-coding genes, yet the majority have no known function. We previously discovered 844 lncRNAs that were genetically linked to breast cancer through genome-wide association studies (GWAS). Here, we show that a subset of these lncRNAs alter breast cancer risk by modulating cell proliferation, and provide evidence that a reduced expression on one lncRNA increases breast cancer risk through aberrant DNA replication and repair.
    METHODS: We performed pooled CRISPR-Cas13d-based knockdown screens in breast cells to identify which of the 844 breast cancer-associated lncRNAs alter cell proliferation. We selected one of the lncRNAs that increased cell proliferation, KILR, for follow-up functional studies. KILR pull-down followed by mass spectrometry was used to identify binding proteins. Knockdown and overexpression studies were performed to assess the mechanism by which KILR regulates proliferation.
    RESULTS: We show that KILR functions as a tumor suppressor, safeguarding breast cells against uncontrolled proliferation. The half-life of KILR is significantly reduced by the risk haplotype, revealing an alternative mechanism by which variants alter cancer risk. Mechanistically, KILR sequesters RPA1, a subunit of the RPA complex required for DNA replication and repair. Reduced KILR expression promotes breast cancer cell proliferation by increasing the available pool of RPA1 and speed of DNA replication. Conversely, KILR overexpression promotes apoptosis in breast cancer cells, but not normal breast cells.
    CONCLUSIONS: Our results confirm lncRNAs as mediators of breast cancer risk, emphasize the need to annotate noncoding transcripts in relevant cell types when investigating GWAS variants and provide a scalable platform for mapping phenotypes associated with lncRNAs.
    Keywords:  Breast cancer; CRISPR; Cas13 screen; Cell proliferation; DNA replication; GWAS; Genetic variants; Long noncoding RNA; lncRNA
    DOI:  https://doi.org/10.1186/s12943-024-02021-y
  3. Chin J Cancer Res. 2024 Apr 30. 36(2): 124-137
    Pyrotinib is effective in both trastuzumab-sensitive and primary resistant HER2-positive breast tumors.
    Jialin Zhang, Gengshen Yin, Chunmiao Ye, Man Feng, Changhua Ji, Wenzhong Zhou, Fei Wang, Lixiang Yu, Shuya Huang, Zhigang Yu.
       Objective: Primary resistance to trastuzumab frequently occurs in human epidermal growth factor receptor 2 (HER2)-positive (+) breast cancer patients and remains a clinical challenge. Pyrotinib is a novel tyrosine kinase inhibitor that has shown efficacy in the treatment of HER2+ breast cancer. However, the efficacy of pyrotinib in HER2+ breast cancer with primary trastuzumab resistance is unknown.
    Methods: HER2+ breast cancer cells sensitive or primarily resistant to trastuzumab were treated with trastuzumab, pyrotinib, or the combination. Cell proliferation, migration, invasion, and HER2 downstream signal pathways were analyzed. The effects of pyrotinib plus trastuzumab and pertuzumab plus trastuzumab were compared in breast cancer cells in vitro and a xenograft mouse model with primary resistance to trastuzumab.
    Results: Pyrotinib had a therapeutic effect on trastuzumab-sensitive HER2+ breast cancer cells by inhibiting phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) and rat sarcoma virus (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase (MAPK)/extracellular-signal regulated kinase (ERK) pathways. In primary trastuzumab-resistant cells, pyrotinib inhibited cell growth, migration, invasion, and HER2 downstream pathways, whereas trastuzumab had no effects. The combination with trastuzumab did not show increased effects compared with pyrotinib alone. Compared with pertuzumab plus trastuzumab, pyrotinib plus trastuzumab was more effective in inhibiting cell proliferation and HER2 downstream pathways in breast cancer cells and tumor growth in a trastuzumab-resistant HER2+ breast cancer xenograft model.
    Conclusions: Pyrotinib-containing treatments exhibited anti-cancer effects in HER2+ breast cancer cells sensitive and with primary resistance to trastuzumab. Notably, pyrotinib plus trastuzumab was more effective than trastuzumab plus pertuzumab in inhibiting tumor growth and HER2 downstream pathways in HER2+ breast cancer with primary resistance to trastuzumab. These findings support clinical testing of the therapeutic efficacy of dual anti-HER2 treatment combining an intracellular small molecule with an extracellular antibody.
    Keywords:  Breast cancer; HER2; pertuzumab; primary resistance; pyrotinib; trastuzumab
    DOI:  https://doi.org/10.21147/j.issn.1000-9604.2024.02.03
  4. Int J Mol Sci. 2024 Apr 24. pii: 4647. [Epub ahead of print]25(9):
    Type II Interleukin-4 Receptor Activation in Basal Breast Cancer Cells Promotes Tumor Progression via Metabolic and Epigenetic Modulation.
    Demond Williams, Ebony Hargrove-Wiley, Wendy Bindeman, Daniel Valent, Adam X Miranda, Jacob Beckstead, Barbara Fingleton.
      Interleukin-4 (IL4) is a Th2 cytokine that can signal through two different receptors, one of which-the type II receptor-is overexpressed by various cancer cells. Previously, we have shown that type II IL4 receptor signaling increases proliferation and metastasis in mouse models of breast cancer, as well as increasing glucose and glutamine metabolism. Here, we expand on those findings to determine mechanistically how IL4 signaling links glucose metabolism and histone acetylation to drive proliferation in the context of triple-negative breast cancer (TNBC). We used a combination of cellular, biochemical, and genomics approaches to interrogate TNBC cell lines, which represent a cancer type where high expression of the type II IL4 receptor is linked to reduced survival. Our results indicate that type II IL4 receptor activation leads to increased glucose uptake, Akt and ACLY activation, and histone acetylation in TNBC cell lines. Inhibition of glucose uptake through the deletion of Glut1 ablates IL4-induced proliferation. Additionally, pharmacological inhibition of histone acetyltransferase P300 attenuates IL4-mediated gene expression and proliferation in vitro. Our work elucidates a role for type II IL4 receptor signaling in promoting TNBC progression, and highlights type II IL4 signaling, as well as histone acetylation, as possible targets for therapy.
    Keywords:  glucose; histone acetylation; interleukin-13; interleukin-4
    DOI:  https://doi.org/10.3390/ijms25094647
  5. Am J Pathol. 2024 Jun;pii: S0002-9440(24)00079-8. [Epub ahead of print]194(6): 1137-1153
    Isolation and Characterization of a Novel Mammary Adenocarcinoma, MCa-P1362, with Hormone Receptor Expression, Human Epidermal Growth Factor Receptor 2 Positivity, and Enrichment in Cancer and Mesenchymal Stem Cells.
    Samir Jana, Wende Li, Pin-Ji Lei, Zixiong Wang, Shaye Kibara, Peigen Huang, Dennis Jones.
      Preclinical models that display spontaneous metastasis are necessary to improve the therapeutic options for hormone receptor-positive breast cancers. Within this study, detailed cellular and molecular characterization was conducted on MCa-P1362, a newly established mouse model of metastatic breast cancer that is syngeneic in BALB/c mice. MCa-P1362 cancer cells express estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2. MCa-P1362 cancer cells proliferate in vitro and in vivo in response to estrogen, yet do not depend on steroid hormones for growth and tumor progression. Analysis of MCa-P1362 tumor explants revealed the tumors contained a mixture of cancer cells and mesenchymal stromal cells. Through transcriptomic and functional analyses of both cancer and stromal cells, stem cells were detected within both populations. Functional studies demonstrated that MCa-P1362 cancer stem cells drove tumor initiation, whereas stromal cells from these tumors contributed to drug resistance. MCa-P1362 may serve as a useful preclinical model to investigate the cellular and molecular basis of breast tumor progression and therapeutic resistance.
    DOI:  https://doi.org/10.1016/j.ajpath.2024.02.013
  6. FASEB J. 2024 May 15. 38(9): e23624
    RPGRIP1L as a new biomarker for prognosis and tumor immune of breast cancer.
    Jianing Yi, Luyao Liu, Yongzhi Chen, Tianjinhao Ding, Peizhi Fan, Jie Yu, Jie Zeng.
      The Retinitis pigmentosa GTPase regulator interacting protein 1-like (RPGRIP1L) gene encodes an important protein that performs various physiological functions. Variants of RPGRIP1L are related to a number of diseases. However, it is currently unknown whether RPGRIP1L is correlated with breast invasive carcinoma (BRCA). In BRCA tissue specimens, the expression of RPGRIP1L was found to be elevated in comparison to its levels in normal breast tissue. A notable decline in survival rates was associated with patients exhibiting heightened RPGRIP1L gene expression. Consistent with these findings, our data also show the above results. Furthermore, elevated expression of RPGRIP1L corresponded with a spectrum of unfavorable clinicopathological features, including the presence of human epidermal growth factor receptor 2 (HER2) positive, estrogen receptor (ER) positive, over 60 years old, T2, N0, and N3. At the same time, our research indicated that 50 genes and 15 proteins were positively related to RPGRIP1L, and that these proteins and genes were mostly involved in T cell proliferation, immune response, cytokine activity, and metabolic regulation. In addition, in the present study, there was a significant correlation between RPGRIP1L expression and immune cell infiltration. Finally, we found that four Chemicals could downregulate the expression of RPGRIP1L. Altogether, our results strongly indicated that RPGRIP1L might serve as a new prognostic biomarker for BRCA.
    Keywords:   RPGRIP1L ; biomarker; breast cancer; cytokine; immune infiltrate; prognosis
    DOI:  https://doi.org/10.1096/fj.202302523R
  7. Arch Pharm Res. 2024 May 11.
    Continuous TNF-α exposure in mammary epithelial cells promotes cancer phenotype acquisition via EGFR/TNFR2 activation.
    Jin-Hee Lee, Steffanus Pranoto Hallis, Mi-Kyoung Kwak.
      Tumor necrosis factor alpha (TNF-α), an abundant inflammatory cytokine in the tumor microenvironment (TME), is linked to breast cancer growth and metastasis. In this study, we established MCF10A cell lines incubated with TNF-α to investigate the effects of continuous TNF-α exposure on the phenotypic change of normal mammary epithelial cells. The established MCF10A-LE cell line, through long-term exposure to TNF-α, displayed cancer-like features, including increased proliferation, migration, and sustained survival signaling even in the absence of TNF-α stimulation. Unlike the short-term exposed cell line MCF10A-SE, MCF10A-LE exhibited elevated levels of epidermal growth factor receptor (EGFR) and subsequent TNF receptor 2 (TNFR2), and silencing of EGFR or TNFR2 suppressed the cancer-like phenotype of MCF10A-LE. Notably, we demonstrated that the elevated levels of NAD(P)H oxidase 4 (NOX4) and the resulting increase in reactive oxygen species (ROS) were associated with EGFR/TNFR2 elevation in MCF10A-LE. Furthermore, mammosphere-forming capacity and the expression of cancer stem cell (CSC) markers increased in MCF10A-LE. Silencing of EGFR reversed these effects, indicating the acquisition of CSC-like properties via EGFR signaling. In conclusion, our results reveal that continuous TNF-α exposure activates the EGFR/TNFR2 signaling pathway via the NOX4/ROS axis, promoting neoplastic changes in mammary epithelial cells within the inflammatory TME.
    Keywords:  Breast cancer; Epidermal growth factor receptor; Reactive oxygen species; Tumor necrosis factor receptor 2; Tumor necrosis factor-alpha
    DOI:  https://doi.org/10.1007/s12272-024-01497-y
  8. Toxicol In Vitro. 2024 May 14. pii: S0887-2333(24)00075-4. [Epub ahead of print] 105845
    LINC02535 + miR-30a-5p combination enhances proliferation and inhibits apoptosis in metastatic breast Cancer cells.
    Wei Lv, Hui Liu, Qi Zheng, Hu Niu.
      Current clinical therapies for metastatic breast cancer (MBC) have limited therapeutic efficacy and induce significant systemic side effects, leading to poor patient compliance. To address this challenge, this investigation focuses on the design of LINC02535 + miR-30a-5p for treating breast cancer. In vitro cytotoxicity studies confirmed that LINC02535 + miR-30a-5p was more effective in 4 T1 cells, with reduced toxicity in NIH3T3 cells. Further verification of cellular morphology was achieved through various biochemical staining methods. Additionally, the antimetastatic attributes of LINC02535 + miR-30a-5p have been evaluated using both migration scratch and Transwell migration assays, which have collectively revealed excellent antimetastatic potential. The DNA fragmentation of the 4 T1 cells was assessed using a comet assay. LINC02535 + miR-30a-5p improved ROS levels and caused mitochondrial membrane potential alterations and DNA damage, which resulted in apoptosis. Therefore, we propose that LINC02535 + miR-30a-5p could be an alternative therapeutic strategy for breast cancer therapy.
    Keywords:  Antimetastasis; Apoptosis; Breast cancer; DNA fragmentation; LINC02535
    DOI:  https://doi.org/10.1016/j.tiv.2024.105845
  9. Sci Rep. 2024 05 16. 14(1): 11219
    D-arabinose induces cell cycle arrest by promoting autophagy via p38 MAPK signaling pathway in breast cancer.
    Zhenning Tang, Hanying Song, Shaojie Qin, Zengjian Tian, Chaolin Zhang, Yang Zhou, Ruizhi Cai, Yongzhao Zhu.
      Breast cancer patients often have a poor prognosis largely due to lack of effective targeted therapy. It is now well established that monosaccharide enhances growth retardation and chemotherapy sensitivity in tumor cells. We investigated whether D-arabinose has capability to restrict the proliferation of tumor cells and its mechanism. Here, we report that D-arabinose induced cytotoxicity is modulated by autophagy and p38 MAPK signaling pathway in breast cancer cell lines. The proliferation of cells was evaluated by CCK-8 and Colony formation assay. The distribution of cells in cell cycle phases was analyzed by flow cytometry. Cell cycle, autophagy and MAPK signaling related proteins were detected by western blotting. Mouse xenograft model was used to evaluate the efficacy of D-arabinose in vivo. The proliferation of cells was dramatically inhibited by D-arabinose exposure in a dose-dependent manner, which was relevant to cell cycle arrest, as demonstrated by G2/M cell cycle restriction and ectopic expression of cell cycle related proteins. Mechanistically, we further identified that D-arabinose is positively associated with autophagy and the activation of the p38 MAPK signaling in breast cancer. In contrast, 3-Ma or SB203580, the inhibitor of autophagy or p38 MAPK, reversed the efficacy of D-arabinose. Additionally, D-arabinose in vivo treatment could significantly inhibit xenograft growth of breast cancer cells. Our findings were the first to reveal that D-arabinose triggered cell cycle arrest by inducing autophagy through the activation of p38 MAPK signaling pathway in breast cancer cells.
    Keywords:   d-Arabinose; Autophagy; Breast cancer; Cell cycle arrest; p38 MAPK signaling pathway
    DOI:  https://doi.org/10.1038/s41598-024-61309-7
  10. Cancers (Basel). 2024 Apr 25. pii: 1666. [Epub ahead of print]16(9):
    Hypomethylation of ATP1A1 Is Associated with Poor Prognosis and Cancer Progression in Triple-Negative Breast Cancer.
    Yesol Kim, Je Yeong Ko, Hyun Kyung Kong, Minyoung Lee, Woosung Chung, Sera Lim, Dasom Son, Sumin Oh, Jee Won Park, Do Yeon Kim, Minju Lee, Wonshik Han, Woong-Yang Park, Kyung Hyun Yoo, Jong Hoon Park.
      Dysregulated DNA methylation in cancer is critical in the transcription machinery associated with cancer progression. Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, but no treatment targeting TNBC biomarkers has yet been developed. To identify specific DNA methylation patterns in TNBC, methyl-binding domain protein 2 (MBD) sequencing data were compared in TNBC and the three other major breast cancer subtypes. Integrated analysis of DNA methylation and gene expression identified a gene set showing a correlation between DNA methylation and gene expression. ATPase Na+/K+-transporting subunit alpha 1 (ATP1A1) was found to be specifically hypomethylated in the coding sequence (CDS) region and to show increased expression in TNBC. The Cancer Genome Atlas (TCGA) database also showed that hypomethylation and high expression of ATP1A1 were strongly associated with poor survival in patients with TNBC. Furthermore, ATP1A1 knockdown significantly reduced the viability and tumor-sphere formation of TNBC cells. These results suggest that the hypomethylation and overexpression of ATP1A1 could be a prognostic marker in TNBC and that the manipulation of ATP1A1 expression could be a therapeutic target in this disease.
    Keywords:  ATP1A1; DNA methylation; prognostic marker; triple-negative breast cancer
    DOI:  https://doi.org/10.3390/cancers16091666
  11. bioRxiv. 2024 Apr 30. pii: 2024.04.28.591568. [Epub ahead of print]
    Chemoresistance to additive PARP/PI3K dual inhibition in triple-negative breast cancer cell lines is associated with adaptive stem cell-like prevalence.
    Paula E Petrella, Jason W Chen, Gabrielle O Ravelo, Benjamin D Cosgrove.
      Cancer stem-like cells (CSCs) are posited to exhibit specialized oncogenic capacity to drive malignancies. CSCs are distinguished by enhanced hallmarks of cancer, including apoptosis avoidance, phenotypic plasticity and aberrant growth pathway signaling. Standard-of-care chemotherapies targeted to rapidly cycling cells routinely fail to eliminate this resistant subpopulation, leading to disease recurrence and metastasis. Triple-negative breast cancer (TNBC), a highly aggressive subtype of breast cancer, is enriched for tumor-propagating CD44 + /CD24 -/low CSCs, which are poorly ablated by chemotherapeutics and are associated with poor prognosis. CD44 governs sustained PI3K signaling in breast cancer, which is essential for CSC maintenance. PI3K inhibition can elicit DNA damage and down-regulate BRCA1 expression, which in turn enhance the synthetic lethality of PARP inhibitors. Here, we examined a dual chemotherapeutic approach targeting these pathways by combining a pan-PI3K inhibitor (Buparlisib) and a PARP1 inhibitor (Olaparib) on a panel of TNBC cell lines with distinct mutational profiles and proportions of CSCs. We observed differential sensitivity to this dual inhibition strategy and varying cellular stress and resistance responses across eight TNBC lines. The dual chemotherapeutic effect is associated with a reduction in S-phase cells, an increased in apoptotic cells and elevated expression of cleaved PARP, indicating a provoked replicative stress response. We observed that PARP/PI3K inhibition efficacy was potentiated by repeated administration in some TNBC lines and identified critical treatment schedules, which further potentiated the dual chemotherapeutic effect. Dual inhibition induced small but significant increases in CSC relative abundance as marked by CD44 + /CD24 -/low or ALDH1 + cells and increased stress and survival signaling in multiple TNBC cell lines, suggesting this sub-population contributes to TNBC chemoresistance. These results suggest the additive effects of PARP and PI3K inhibition against CSC phenotypes may be enhanced by temporally-staged administration in TNBC cells.
    DOI:  https://doi.org/10.1101/2024.04.28.591568
  12. Cell Mol Biol Lett. 2024 May 14. 29(1): 71
    FGFR2-triggered autophagy and activation of Nrf-2 reduce breast cancer cell response to anti-ER drugs.
    Monika Gorska-Arcisz, Marta Popeda, Marcin Braun, Dominika Piasecka, Joanna I Nowak, Kamila Kitowska, Grzegorz Stasilojc, Marcin Okroj, Hanna M Romanska, Rafal Sadej.
       BACKGROUND: Genetic abnormalities in the FGFR signalling occur in 40% of breast cancer (BCa) patients resistant to anti-ER therapy, which emphasizes the potential of FGFR-targeting strategies. Recent findings indicate that not only mutated FGFR is a driver of tumour progression but co-mutational landscapes and other markers should be also investigated. Autophagy has been recognized as one of the major mechanisms underlying the role of tumour microenvironment in promotion of cancer cell survival, and resistance to anti-ER drugs. The selective autophagy receptor p62/SQSTM1 promotes Nrf-2 activation by Keap1/Nrf-2 complex dissociation. Herein, we have analysed whether the negative effect of FGFR2 on BCa cell response to anti-ER treatment involves the autophagy process and/or p62/Keap1/Nrf-2 axis.
    METHODS: The activity of autophagy in ER-positive MCF7 and T47D BCa cell lines was determined by analysis of expression level of autophagy markers (p62 and LC3B) and monitoring of autophagosomes' maturation. Western blot, qPCR and proximity ligation assay were used to determine the Keap1/Nrf-2 interaction and Nrf-2 activation. Analysis of 3D cell growth in Matrigel® was used to assess BCa cell response to applied treatments. In silico gene expression analysis was performed to determine FGFR2/Nrf-2 prognostic value.
    RESULTS: We have found that FGFR2 signalling induced autophagy in AMPKα/ULK1-dependent manner. FGFR2 activity promoted dissociation of Keap1/Nrf-2 complex and activation of Nrf-2. Both, FGFR2-dependent autophagy and activation of Nrf-2 were found to counteract the effect of anti-ER drugs on BCa cell growth. Moreover, in silico analysis showed that high expression of NFE2L2 (gene encoding Nrf-2) combined with high FGFR2 expression was associated with poor relapse-free survival (RFS) of ER+ BCa patients.
    CONCLUSIONS: This study revealed the unknown role of FGFR2 signalling in activation of autophagy and regulation of the p62/Keap1/Nrf-2 interdependence, which has a negative impact on the response of ER+ BCa cells to anti-ER therapies. The data from in silico analyses suggest that expression of Nrf-2 could act as a marker indicating potential benefits of implementation of anti-FGFR therapy in patients with ER+ BCa, in particular, when used in combination with anti-ER drugs.
    Keywords:  Autophagy; FGFR2; Keap1; Luminal breast cancer; Nrf-2; p62
    DOI:  https://doi.org/10.1186/s11658-024-00586-6
  13. Mol Med. 2024 May 17. 30(1): 61
    Extracellular matrix marker LAMC2 targets ZEB1 to promote TNBC malignancy via up-regulating CD44/STAT3 signaling pathway.
    Ding Wang, Kailibinuer Keyoumu, Rongji Yu, Doudou Wen, Hao Jiang, Xinchun Liu, Xiaotang Di, Shubing Zhang.
       BACKGROUND: Triple negative breast cancer (TNBC) is a heterogeneous and aggressive disease characterized by a high risk of mortality and poor prognosis. It has been reported that Laminin γ2 (LAMC2) is highly expressed in a variety of tumors, and its high expression is correlated with cancer development and progression. However, the function and mechanism by which LAMC2 influences TNBC remain unclear.
    METHODS: Kaplan-Meier survival analysis and Immunohistochemical (IHC) staining were used to examine the expression level of LAMC2 in TNBC. Subsequently, cell viability assay, wound healing and transwell assay were performed to detect the function of LAMC2 in cell proliferation and migration. A xenograft mouse model was used to assess tumorigenic function of LAMC2 in vivo. Luciferase reporter assay and western blot were performed to unravel the underlying mechanism.
    RESULTS: In this study, we found that higher expression of LAMC2 significantly correlated with poor survival in the TNBC cohort. Functional characterization showed that LAMC2 promoted cell proliferation and migration capacity of TNBC cell lines via up-regulating CD44. Moreover, LAMC2 exerted oncogenic roles in TNBC through modulating the expression of epithelial-mesenchymal transition (EMT) markers. Luciferase reporter assay verified that LAMC2 targeted ZEB1 to promote its transcription. Interestingly, LAMC2 regulated cell migration in TNBC via STAT3 signaling pathway.
    CONCLUSION: LAMC2 targeted ZEB1 via activating CD44/STAT3 signaling pathway to promote TNBC proliferation and migration, suggesting that LAMC2 could be a potential therapeutic target in TNBC patients.
    Keywords:  CD44; EMT; LAMC2; Migration; STAT3; Triple negative breast cancer; ZEB1
    DOI:  https://doi.org/10.1186/s10020-024-00827-6
  14. bioRxiv. 2024 May 02. pii: 2024.05.01.592097. [Epub ahead of print]
    Insulin Resistance Increases TNBC Aggressiveness and Brain Metastasis via Adipocyte-derived Exosomes.
    Yuhan Qiu, Andrew Chen, Rebecca Yu, Pablo Llevenes, Michael Seen, Naomi Y Ko, Stefano Monti, Gerald V Denis.
      Patients with triple negative breast cancer (TNBC) and comorbid Type 2 Diabetes (T2D), characterized by insulin resistance of adipose tissue, have higher risk of metastasis and shorter survival. Adipocytes are the main non-malignant cells of the breast tumor microenvironment (TME). However, adipocyte metabolism is usually ignored in oncology and mechanisms that couple T2D to TNBC outcomes are poorly understood. Here we hypothesized that exosomes, small vesicles secreted by TME breast adipocytes, drive epithelial-to-mesenchymal transition (EMT) and metastasis in TNBC via miRNAs. Exosomes were purified from conditioned media of 3T3-L1 mature adipocytes, either insulin-sensitive (IS) or insulin-resistant (IR). Murine 4T1 cells, a TNBC model, were treated with exosomes in vitro (72h). EMT, proliferation and angiogenesis were elevated in IR vs. control and IS. Brain metastases showed more mesenchymal morphology and EMT enrichment in the IR group. MiR-145a-3p is highly differentially expressed between IS and IR, and potentially regulates metastasis.
    Significance: IR adipocyte exosomes modify TME, increase EMT and promote metastasis to distant organs, likely through miRNA pathways. We suggest metabolic diseases such as T2D reshape the TME, promoting metastasis and decreasing survival. Therefore, TNBC patients with T2D should be closely monitored for metastasis, with metabolic medications considered.
    DOI:  https://doi.org/10.1101/2024.05.01.592097
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