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Tumor growth increases compressive stress within a tissue, which is associated with solid tumor progression. However, very little is known about how compressive stress contributes to tumor progression. Here, we show that compressive stress induces glycolysis in human breast cancer associated fibroblast (CAF) cells and thereby contributes to the expression of epithelial to mesenchymal (EMT)- and angiogenesis-related genes in breast cancer cells. Lactate production was increased in compressed CAF cells, in a manner dependent on the expression of metabolic genes ENO2 , HK2 , and PFKFB3 . Conditioned medium from compressed CAFs promoted the proliferation of breast cancer cells and the expression of EMT and/or angiogenesis-related genes. In patient tissues with high compressive stress, the expression of compression-induced metabolic genes was significantly and positively correlated with EMT and/or angiogenesis-related gene expression and metastasis size. These findings illustrate a mechanotransduction pathway involving stromal glycolysis that may be relevant also for other solid tumours.

ObjectiveThe mechanisms underlying type 2 diabetes resolution after Roux-en-Y gastric bypass (RYGB) are unclear. We suspected that glucose excretion may occur in the small bowel based on observations in humans. The aim of this study was to evaluate the mechanisms underlying serum glucose excretion in the small intestine and its contribution to glucose homeostasis after bariatric surgery.Design2-Deoxy-2-[18F]-fluoro-D-glucose (FDG) was measured in RYGB-operated or sham-operated obese diabetic rats. Altered glucose metabolism was targeted and RNA sequencing was performed in areas of high or low FDG uptake in the ileum or common limb. Intestinal glucose metabolism and excretion were confirmed using 14C-glucose and FDG. Increased glucose metabolism was evaluated in IEC-18 cells and mouse intestinal organoids. Obese or ob/ob mice were treated with amphiregulin (AREG) to correlate intestinal glycolysis changes with changes in serum glucose homeostasis.ResultsThe AREG/EGFR/mTOR/AKT/GLUT1 signal transduction pathway was activated in areas of increased glycolysis and intestinal glucose excretion in RYGB-operated rats. Intraluminal GLUT1 inhibitor administration offset improved glucose homeostasis in RYGB-operated rats. AREG-induced signal transduction pathway was confirmed using IEC-18 cells and mouse organoids, resulting in a greater capacity for glucose uptake via GLUT1 overexpression and sequestration in apical and basolateral membranes. Systemic and local AREG administration increased GLUT1 expression and small intestinal membrane translocation and prevented hyperglycaemic exacerbation.ConclusionBariatric surgery or AREG administration induces apical and basolateral membrane GLUT1 expression in the small intestinal enterocytes, resulting in increased serum glucose excretion in the gut lumen. Our findings suggest a novel, potentially targetable glucose homeostatic mechanism in the small intestine.

Introduction: Hyperlipidemia has been associated with increased risk of advanced stage and high Gleason grade prostate cancer (PCa), yet the underlying mechanism is not completely understood. Quaking (QKI) is an RNA-binding protein (RBP) that regulate lipid metabolism. For PCa, QKI overexpression has been associated with increased chance of metastatic recurrence. Method: We performed RNA sequencing of prostate cancer tissues of hyperlipidemia (n = 12) and normolipidemia (n=32). Tissue samples were acquired by MRI-US fusion targeted biopsy. DESeq2 and GSEA was used to identify differently expressed genes and enriched genesets. A web-based RBP motif screening tool TRANSITE was utilized to identify active RBPs in hyperlipidemia-associated PCa. Results: PCa samples of hyperlipidemia patients exhibited poorer histology than normolipidemia PCA. RNA sequencing found that hyperlipidemia-associated PCa is enriched of Myc-regulated genes as well as interferon or innate immunity-associated genes. Interestingly, hyperlipidemia-associated PCa gene expression signature identified PCa samples devoid of common PCa genetic alterations - TMPRSS2-ERG fusion and PTEN deletion/mutation. RBP motif screening found QKI as one of the top enriched RBP in hyperlipidemia-associated PCa transcriptome. In a separate a consecutive radical prostatectomy series (n=190), we found that QKI-high (immunohistochemistry staining score 2-3) tumors had significantly higher serum cholesterol than QKI-low (score 0-1) tumors. Overexpression and knockdown experiments proved that QKI is responsible of rapid cell proliferation and interferon-related inflammatory gene expressions, In silico analysis predicted QKI overexpressing cancer cells are susceptive to stain-mediated ferroptosis-like cell death. Mechanistically, QKI regulates expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), which dictates the sensitivity of QKI overexpressing cells to ferroptosis. Conclusion: Hyperlipidemia was associated with aggressive pathologic characteristics of PCa without TMPRSS2-ERG fusion or PTEN deletion/mutation, and high tissue expression of QKI, an RNA-binding protein. QKI overexpression in PCa increased sensitivity to ACSL4-mediated ferroptosis by statins. This explains the epidemiological associations between hyperlipidemia and PCa, and will guide molecular subtype-driven drug repurposing studies. Citation Format: Hyun Ho Han, Jin Sol Sung, Dong Wook Song, Cheol Keun Park, Nam Hoon Cho, Young Deuk Choi, Woo Jin Ko. Hyperlipidemia promotes aggressive variant prostate cancer via RNA-binding protein Quaking [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2270.

Integrin beta4 neoexpression is induced in cancer-associated fibroblasts (CAFs) by some triple negative breast cancer cells (MDA-MB-231 and BT-20) through a contact-dependent manner. Integrin beta4 expression is well known to contribute to the migration and survival of cancer cells. However, there is very little known about the role of integrin beta4 expression in CAFs, especially in the aspect of tumor progression. In our study, we found that the exogenous expression of integrin beta4 increased the lactate production of CAFs. The observation made us to hypothesize that integrin beta4 neoexpression is associated with the mitophagy, a cause for aerobic glycolysis, in CAFs. To confirm the assumption, the expression alteration of mitophagy-related genes was first screened in the CAF transfected with integrin beta4 overexpression plasmid. BCL2 interacting protein 3 like (BNIP3L) and microtubule associated protein 1 light chain 3 alpha-II (LC3-II) were significantly upregulated in the integrin beta4 overexpressing CAFs, which was reversed both in the knockdown of integrin beta4 expression and the treatment with an integrin beta4 inhibitor. Autophagosome maturation and lysosomal fusion were also increased in the integrin beta4 overexpressing CAFs compared to the control. Phosphorylation level of c-Jun was upregulated by integrin beta4 overexpression in CAFs and was able to bind to the putative promoter regions of BNIP3L and LC3-II. Taken together, these results demonstrate that integrin beta4 neoexpression induces upregulation of BNIP3L and LC3-II ultimately leading to mitophagy in CAFs, contributing to cancer metabolism via mitophagy-induced lactate production, namely reverse Warburg effect. Citation Format: Jin Sol Sung, Suki Kang, Joo Hyun Lee, Seong Gyeong Mun, Baek Gil Kim, Nam Hoon Cho. Integrin beta4-induced mitophagy promotes the lactate production of cancer-associated fibroblasts in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1456.