American journal of physiology. Cell physiology最新文献

{"title":"MCF7 breast cancer anabolic capacity reduced with CRISPR/Cas9-mediated stable overexpression of DEPTOR.","authors":"J William Deaver, Patrick J Ryan, Colleen L O'Reilly, Selina Uranga, Sara Mata López, Melinda Sheffield-Moore, Peter P Nghiem, Steven E Riechman, James D Fluckey","doi":"10.1152/ajpcell.00682.2023","DOIUrl":"https://doi.org/10.1152/ajpcell.00682.2023","url":null,"abstract":"<p><p>The hyperactivation of mTOR is a significant contributor to the development and progression of a number of human diseases, including a majority of human cancers. Although there have been many scientific and clinical efforts to reduce the impact of mTOR hyperactivation on downstream cellular metabolism, we aimed to mitigate this hyperactivation through a novel targeted gene edit of the intrinsic mTOR inhibitor, DEP domain containing MTOR interacting protein (DEPTOR), in MCF7 human breast cancer cells. Using publicly available bioinformatics tools, we demonstrate that DEPTOR gene expression is low in breast cancers compared with healthy tissues and that DEPTOR expression predicts overall survival, recurrence-free survival, and distant metastasis-free survival in breast cancer patients. We show that a directed overexpression of DEPTOR protein leads to significant alteration of downstream mTORC1 targets and subsequently reduces overall rates of protein synthesis. In addition, treatment of DEPTOR overexpressing cells with small-molecule DEPTOR inhibitor NSC126405 leads to a reversal of this effect, indicating a direct causal mechanism between DEPTOR protein levels and mTORC1 activation.<b>NEW & NOTEWORTHY</b> We identify DEPTOR as a predictor of mortality in breast cancer and show that precision gene editing to restore DEPTOR expression in breast cancer slows cell growth by inhibiting mTOR activity.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":"328 2","pages":"C670-C678"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143405139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HOXA3 activates USP15 to suppress autophagy and promote M2-type macrophage polarization in renal cell carcinoma via facilitating the deubiquitination of SQSTM1.","authors":"Huihuang Li, Yang Li, Zhiyong Chen, Cheng He","doi":"10.1152/ajpcell.00712.2024","DOIUrl":"10.1152/ajpcell.00712.2024","url":null,"abstract":"<p><p>The disease burden of renal cell carcinoma (RCC) has decreased in recent years with advances in treatment, but its pathogeny still remains elusive. We aim to study the role of homeobox A3 (HOXA3)/ubiquitin-specific peptidase 15 (USP15)/SQSTM1 axis on autophagy and M2-type macrophage polarization in RCC. In this study, cell apoptosis and proliferation were assessed by flow cytometry and CCK-8. Autolysosome fusion was observed by immunofluorescence detection of LC3 and LAMP2. The binding between HOXA3 and USP15 promoter was tested by chromatin immunoprecipitation (ChIP), EMSA, and dual-luciferase reporter assays. Also, the interaction between deubiquitinated enzyme (DUB) USP15 and SQSTM1, and ubiquitinated level of SQSTM1 were determined by co-immunoprecipitation (Co-IP) assay. Expression levels of HOXA3, USP15, C-C motif chemokine 2 (CCL2), CCL2 receptor (CCR2), M2-type macrophages, and autophagy-related markers were measured by Western blot, quantitative reverse transcription PCR (RT-qPCR), ELISA, and immunohistochemistry. Role of HOXA3/USP15 axis was verified by xenograft tumor experiment in vivo. We showed upregulated HOXA3 in RCC tissues and cells, and RCC tissues with metastasis showed higher HOXA3 level. The higher HOXA3 expression was relevant to worse overall survival in patients with RCC. HOXA3 induced RCC cell proliferation, and suppressed autophagy and apoptosis via transcriptionally activating USP15 expression. USP15 then induced deubiquitination modification of SQSTM1 in RCC cells. SQSTM1 supported M2-type macrophage polarization by inducing CCL2 secretion. HOXA3 or USP15 knockdown suppressed tumor growth and M2-type macrophage infiltration in vivo. In conclusion, HOXA3 transcriptionally activates USP15 expression, and upregulated USP15 facilitates the deubiquitination of SQSTM1 in RCC. This process on the one hand suppresses autophagy, on the other hand increases M2-type macrophage polarization through stimulating the secretion of CCL2.<b>NEW & NOTEWORTHY</b> We report a novel finding that highly expressed homeobox A3 (HOXA3) transcriptionally activates the expression of ubiquitin-specific peptidase 15 (USP15), resulting in the promotion of deubiquitination of SQSTM1. This process on the one hand suppresses autophagy in renal cell carcinoma (RCC), on the other hand increases M2-type macrophage polarization in the tumor microenvironment through stimulating the secretion of C-C motif chemokine 2 (CCL2).</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C576-C594"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142909089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The tRF-33/IGF1 axis dysregulates mitochondrial homeostasis in HER2-negative breast cancer.","authors":"Yuming Lou, Bifei Fu, Lutong Liu, Jialu Song, Mengying Zhu, Chaoyang Xu","doi":"10.1152/ajpcell.00588.2024","DOIUrl":"10.1152/ajpcell.00588.2024","url":null,"abstract":"<p><p>Transfer RNA-derived small RNAs (tsRNAs), a recently identified noncoding RNA subset, are mainly classified into transfer RNA (tRNA)-derived small RNA fragments (tRFs) and tRNA-derived stress-induced RNAs (tiRNAs). tsRNAs dysregulation is frequently observed in numerous cancer types, suggesting involvement in tumorigenesis. However, their functions in breast cancer (BC) remain to be fully understood. Here, it was discovered that tRF-33-MEF91SS2PMFI0Q (tRF-33), derived from mature tRNA-Lys^TTT, was markedly upregulated in human epidermal receptor 2 (HER2)-negative BC cells and tissue samples. tRF-33 stimulated the proliferation, migration, and invasiveness of BC cells in vitro and facilitated tumor progression in vivo. Mechanistically, tRF-33 was found for the first time to bind directly to the 3'-UTR of IGF1, resulting in downregulation of both its mRNA and protein and thus affecting mitochondrial homeostasis and progression of BC. These results demonstrate a novel tsRNA modulatory mechanism and a potential direction for treating HER2-negative BC.<b>NEW & NOTEWORTHY</b> In this study, we identified differential expression of tRNA fragments in HER2-negative BC tissues compared with adjacent normal tissues, observing significant upregulation of an i-tRF type tRF-33-MEF91SS2PMFI0Q (tRF-33) in the tumor tissue. We also found that tRF-33 promoted tumorigenesis in BC cells. We demonstrated for the first time that IGF1 was a target gene of tRF-33 and also showed that the tRF-33/IGF1 axis impaired mitochondrial dynamics, thus affecting mitochondrial homeostasis and promoting HER2-negative BC progression.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C627-C638"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142942639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"p300 maintains primordial follicle activation by repressing <i>VEGFA</i> transcription.","authors":"Meina He, Yaoyun Liang, Xiaoran Nie, Tuo Zhang, Danqing Zhao, Jixian Zhang, Huan Lin, Zhirui Zeng, Xingyu Song, Yitong Wang, Shiling Ran, Shuyun Zhao, Tengxiang Chen, Chunlin Zhang, Zhanhui Feng","doi":"10.1152/ajpcell.00198.2024","DOIUrl":"10.1152/ajpcell.00198.2024","url":null,"abstract":"<p><p>During the reproductive life, most primordial follicles (PFs) remain dormant for years or decades, while some are progressively activated for development. Misactivation of primordial follicles can cause ovarian diseases, for example, premature ovarian insufficiency (POI). Our results show that p300 expression increased with primordial follicle activation. Using a p300 inhibitor resulted in premature activation of primordial follicles in cultured mouse ovaries. Conversely, the ratio of primordial follicle activation was markedly decreased upon culturing with the p300 agonist. Furthermore, p300 regulated primordial follicle activation by inhibiting <i>Vegfa</i> transcription in granulosa cells. In addition, this study was extended to potential clinical applications, showing that short-term treatment with a p300 inhibitor in vitro significantly increased primordial follicle activation in newborn mouse ovaries after the renal subcapsular transplantation in female NSG mice. Our results revealed that p300 controls the activation of primordial follicles in mammalian ovaries.<b>NEW & NOTEWORTHY</b> In this study, our results show that p300 expression increases with primordial follicle activation. A p300 inhibitor results in premature activation of primordial follicles in cultured mouse ovaries. Conversely, the ratio of primordial follicle activation markedly decreases upon culturing with the p300 agonist. Furthermore, p300 regulates primordial follicle activation by inhibiting <i>Vegfa</i> transcription in granulosa cells.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C514-C527"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142602600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"USP35 promotes breast cancer progression by regulating PFK-1 ubiquitination to mediate glycolysis.","authors":"Weibin Lian, Chengye Hong, Debo Chen, Chuan Wang","doi":"10.1152/ajpcell.00733.2024","DOIUrl":"10.1152/ajpcell.00733.2024","url":null,"abstract":"<p><p>Ubiquitin-specific protease 35 (<i>USP35</i>) was found to be involved in various tumor progression, but its role in breast cancer remains largely unknown. USP35 mRNA and protein expression in breast cancer tissues and cells were evaluated by quantitative real-time PCR and Western blot, respectively. Subsequently, flow cytometry and 5-ethynyl-2'-deoxyuridine labeling were used to evaluate breast cancer cell apoptosis and proliferation. Cellular glycolytic function was analyzed using the Seahorse assay and various kits. Furthermore, co-immunoprecipitation (Co-IP) and immunoprecipitation assays were utilized to validate the deubiquitylation mechanism of USP35. Finally, a subcutaneous human xenograft tumor model was established in nude mice to verify the effect of USP35 in vivo. By examining the clinical samples and cell lines, we found that USP35 expression was significantly upregulated in breast cancer. Further functional studies showed that knockdown USP35 expression inhibited cell proliferation and promoted apoptosis. In addition, knockdown of USP35 decreased phosphofructokinase1 (PFK-1) expression and was associated with lower extracellular acidification rate and oxygen consumption rate compared with sh-Control. Co-IP assays identified PFK-1 as a direct deubiquitiation target of USP35. Importantly, we demonstrated that PFK-1 is an essential mediator for USP35-induced cell proliferation and glycolysis in vitro and in vivo. This study identified that USP35 regulates the proliferation and glycolysis of breast cancer cells by mediating the ubiquitination level of PFK-1. The USP35/PFK-1 axis offers novel insight for the treatment of breast cancer.<b>NEW & NOTEWORTHY</b> This study identified that USP35 regulates the proliferation and glycolysis of breast cancer cells by mediating the ubiquitination level of PFK-1. The USP35/PFK-1 axis offers novel insight for the treatment of breast cancer.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C355-C366"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142876021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Filamin A C-terminal fragment modulates Orai1 expression by inhibition of protein degradation.","authors":"Alvaro Macias-Díaz, Joel Nieto-Felipe, Isaac Jardín, Pedro J Camello, Eva M Martinez-Quintana, Gines M Salido, Tarik Smani, Jose J Lopez, Juan A Rosado","doi":"10.1152/ajpcell.00745.2024","DOIUrl":"10.1152/ajpcell.00745.2024","url":null,"abstract":"<p><p>Filamin A (FLNA) is an actin-binding protein that has been reported to interact with STIM1 modulating the activation of Orai1 channels. Cleaving of FLNA by calpain leads to a C-terminal fragment that is involved in a variety of functional and pathological events, including pro-oncogenic activity in different types of cancer. Here, we show that full-length FLNA is downregulated in samples from patients with colon cancer as well as in the adenocarcinoma cell line HT-29. This is consistent with an increased calpain-dependent FLNA cleaving with enhanced expression of the C-terminal FLNA fragment accompanied by enhanced expression of Orai1 and STIM1, as well as store-operated Ca²⁺ entry (SOCE). To further explore the mechanism underlying the enhancement of SOCE by the C-terminal FLNA fragment, we expressed in HEK-293 cells the C-terminal FLNA region encompassing repeats 16-24 (FLNA^16-24 fragment), which enhanced both Orai1 and STIM1 as well as SOCE. Transfection of the FLNA^16-24 fragment attenuates Orai1 and STIM1 protein degradation, and, specifically, abrogates Orai1α lysosomal degradation and retains this channel in the plasma membrane. However, the C-terminal FLNA fragment did not induce a detectable modification in Orai1β degradation. Due to the relevance of SOCE in cell physiology, our results provide evidence of a novel mechanism for the regulation of Ca²⁺ influx with relevant pathophysiological implications.<b>NOTE & NOTEWORTHY</b> FLNA cleaving by calpain has been observed in a variety of tumoral, including prostate and colorectal cancer cells, as well as in nontumoral cells, leading to a C-terminal fragment encompassing repeats 16-24. Expression of the FLNA^16-24 fragment in HEK-293 cells enhances Orai1 and STIM1 expression, as well as SOCE, a mechanism mediated by attenuation of Orai1α and STIM1 degradation, providing evidence for a novel mechanism for the regulation of SOCE in normal and malignant cells.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":"328 2","pages":"C657-C669"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel endocytosis inhibitors block entry of HIV-1 Tat into neural cells.","authors":"Olga Klaudia Szewczyk-Roszczenko, Piotr Roszczenko, Anna Shmakova, Ihor Yushyn, Serhii Holota, Olexandr Karpenko, Robert Czarnomysy, Anna Bielawska, Yegor Vassetzky, Roman Lesyk, Krzysztof Bielawski","doi":"10.1152/ajpcell.00723.2024","DOIUrl":"10.1152/ajpcell.00723.2024","url":null,"abstract":"<p><p>Many pathogens including viruses enter cells by endocytosis. We identified and evaluated novel endocytosis inhibitors capable of blocking the entry of the HIV-1 Transactivation of Transcription protein (Tat) protein into neuronal cells and investigated their potential protective properties against Tat-induced neurotoxicity. In this study, the compounds Les-6631 and Les-6633 were synthesized and assessed. The effects of these compounds on the internalization of dextran and the cell-penetrating peptide (CPP) Tat-Cy5 complex in nerve cells were examined. In addition, the ability of these compounds to protect against oxidative stress and DNA damage induced by the full-length Tat protein was investigated. Les-6631 and Les-6633 were found to inhibit endocytosis better than the classical endocytosis inhibitor chlorpromazine, thereby effectively preventing the entry of the Tat protein into nerve cells. Moreover, compounds demonstrated the capacity to reduce oxidative stress and protect DNA from Tat-induced damage. In a neuro-AIDS model, both compounds proved effective in preventing neurotoxicity associated with HIV-1 infection, indicating its potential for therapeutic applications. Les-6631 and Les-6633 thus can protect cells from the harmful effects of pathogens. Their use in a neuro-AIDS model suggests a potential application in protective therapies for the nervous system in patients with HIV.<b>NEW & NOTEWORTHY</b> This study identifies novel rhodadyn-based inhibitors, Les-6631 and Les-6633, which selectively block dynamin's GTPase activity while sparing clathrin-mediated pathways. They effectively inhibit cellular uptake, protect neural cells from HIV-1 Tat-induced oxidative stress, and reduce mitochondrial and DNA damage. Their selective dynamin inhibition and antioxidant properties highlight their therapeutic potential for neurodegeneration and viral infections, offering cell protection without disrupting essential endocytic functions.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C404-C413"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142881074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative response of casein protein hydrolysate-fed young and older human serum on in vitro muscle protein metabolism and myotube size.","authors":"Martina Pauk, Miryam Amigo-Benavent, Bijal Patel, Philip M Jakeman, Brian P Carson","doi":"10.1152/ajpcell.00117.2024","DOIUrl":"10.1152/ajpcell.00117.2024","url":null,"abstract":"<p><p>In this study, we used an ex vivo-in vitro model to assess the effect of feeding older (50-70 yr) adults a casein protein hydrolysate (CPH) compared with nonbioactive nonessential amino acid (NEAA) supplement on muscle protein synthesis (MPS) and markers of muscle protein breakdown (MPB). As a secondary objective, to assess any attenuation with aging, we compared the anabolic response to CPH-fed serum from older and young adults. Serum from seven healthy older and seven young men following overnight fast and 60-min postprandial ingestion of CPH or NEAA (0.33 g·kg^-1 body mass) was used to condition C2C12 myotube media. Analysis by two-way ANOVA of the fed relative to fasted MPS response revealed a main effect for protein type in pmTOR (<i>P</i> = 0.009), p70S6K (<i>P</i> = 0.031), p4E-BP1 (<i>P</i> = 0.047), and MPS (<i>P</i> = 0.041) with a greater response to CPH-fed serum, and interaction effects (age × protein) between young and old serum for pmTOR (<i>P</i> = 0.009) and p70S6K (<i>P</i> = 0.016). In addition, significant changes in myotube diameter (<i>P</i> = 0.049), atrogin-1 (<i>P</i> = 0.004), and MuRF-1 (<i>P</i> = 0.012) in response to CPH-fed compared with fasted serum were observed with no differences between young and old serum. In conclusion, this study demonstrated that CPH-fed serum from both young and older (50-70 yr) adults can stimulate MPS and muscle growth and can suppress biomarkers of muscle protein breakdown processes.<b>NEW & NOTEWORTHY</b> This study extended previously developed coculture models and found that treating skeletal muscle cells with ex vivo human serum following feeding with a casein protein hydrolysate resulted in greater protein signaling, muscle protein synthesis, muscle growth, and lower expression of genes related to muscle protein breakdown compared with feeding with a nonessential amino acid control. These findings were similar using serum from young and older adults.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C595-C603"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142977208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth differentiation factor 15 is a glucose-downregulated gene acting as the cross talk between stroma and cancer cells of the human bladder.","authors":"Kang-Shuo Chang, Syue-Ting Chen, Wei-Yin Lin, Shu-Yuan Hsu, Hsin-Ching Sung, Yu-Hsiang Lin, Tsui-Hsia Feng, Chen-Pang Hou, Horng-Heng Juang","doi":"10.1152/ajpcell.00230.2024","DOIUrl":"10.1152/ajpcell.00230.2024","url":null,"abstract":"<p><p>Hyperglycemia and hyperglycosuria, two primary characteristics of diabetes mellitus, may increase the risk of cancer initiation, particularly for bladder cancer. The effectiveness of metformin, a common antidiabetic agent, is determined by its ability to induce growth differentiation factor 15 (GDF15). However, the mechanism of the GDF15 in relation to glucose, which influences the tumor microenvironment in the human bladder, is not fully understood. This study explores the potential roles of GDF15 in response to glucose in the human bladder. High glucose treatment (30 mM) enhanced phosphorylation of AKT at S473 and AMP-activated protein kinase α1/2 (AMPKα1/2) at S485 to block the counteracting effect of metformin on the AMPK activity in bladder cancer and stroma [human bladder stromal fibroblast (HBdSF) and human bladder smooth muscle cell (HBdSMC)] cells compared with normal glucose treatment (5 mM). Metformin modulated the expressions of GDF15, NDRG1, Maspin, and epithelial-to-mesenchymal transition (EMT) markers to attenuate cell proliferation and invasion of bladder cancer cells. Caffeic acid phenethyl ester (CAPE), like metformin, behaves as an inducer of AMPK activity to stimulate GDF15 expression. Knockdown of GDF15 blocked the downregulation of CAPE on the contraction of HBdSMCs. Both CAPE-induced GDF15 expression and the supernatant from bladder cancer cells with overexpressing GDF15 impeded the HBdSF and HBdSMC migration, suggesting that CAPE-upregulated GDF15 blocked the cell migration. These findings reveal that high glucose treatment inhibits the counteracting effects of either metformin or CAPE on the AMPK activity and GDF15 is downregulated by glucose and induced by metformin and CAPE in both stroma and cancer cells. Furthermore, GDF15 is an antitumor gene facilitating communication between stroma and cancer cells in the human bladder.<b>NEW & NOTEWORTHY</b> This study investigates the counteraction of either CAPE or metformin with the AMPK activity increasing GDF15 expression in human bladder cells. The findings are the first study to indicate the secretion of GDF15 from cancer and stroma cells via autocrine or paracrine mechanisms. Our study suggests that GDF15, an antitumor gene in the human bladder induced by AMPK inducers, acts as a communication link between stroma and cancer cells in the human bladder.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C557-C573"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142977223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbohydrate ingestion eliminates hypoglycemia and improves endurance exercise performance in triathletes adapted to very low- and high-carbohydrate isocaloric diets.","authors":"Philip J Prins, Timothy D Noakes, Alex Buga, Hayden D Gerhart, Brandon M Cobb, Dominic P D'Agostino, Jeffrey S Volek, Jeffrey D Buxton, Kara Heckman, Emma Plank, Samuel DiStefano, Isaak Flaming, Lauren Kirsch, Britta Lagerquist, Emily Larson, Andrew P Koutnik","doi":"10.1152/ajpcell.00583.2024","DOIUrl":"10.1152/ajpcell.00583.2024","url":null,"abstract":"<p><p>Very-low-carbohydrate diets (LCHF; <50 g/day) have been debated for their potential to lower pre-exercise muscle and liver glycogen stores and metabolic efficiency, risking premature fatigue. It is also hypothesized that carbohydrate ingestion during prolonged exercise delays fatigue by increasing carbohydrate oxidation, thereby sparing muscle glycogen. Leveraging a randomized crossover design, we evaluated performance during strenuous time-to-exhaustion (70% V̇o_2max) tests in trained triathletes following 6-wk high-carbohydrate (HCLF, 380 g/day) or very-low-carbohydrate (LCHF, 40 g/day) diets to determine <i>1</i>) if adoption of the LCHF diet impairs time-to-exhaustion performance, <i>2</i>) whether carbohydrate ingestion (10 g/h) 6-12× lower than current CHO fueling recommendations during low glycogen availability (>15-h pre-exercise overnight fast and/or LCHF diet) improves time to exhaustion by preventing exercise-induced hypoglycemia (EIH; <3.9 mmol/L; <70 mg/dL), and <i>3</i>) the \"keto-adaptation\" time course through continuous substrate monitoring while caloric intake, physical activity, and fat-free mass are maintained. Time-to-exhaustion performance was similar across both dietary interventions. Minimal carbohydrate supplementation prevented EIH and significantly increased time to exhaustion equivalently in LCHF and HCLF interventions (22%). The LCHF diet significantly lowered 24-h glucose concentrations, which normalized after 4 wk, at the same timepoint peak blood ketone (<i>R</i>-β-hydroxybutyrate) concentrations normalized. These findings <i>1</i>) demonstrate that an LCHF diet sustains strenuous endurance performance, <i>2</i>) establish that minimal carbohydrate supplementation was sufficient to enhance exercise performance on LCHF and HCLF diets by mitigating EIH, and <i>3</i>) indicate that a minimum 4-wk adaptation period to an LCHF diet is required to ensure normalization of metabolic homeostasis, glycemic control, and exercise performance.<b>NEW & NOTEWORTHY</b> This study examines the belief that very-low-carbohydrate diets (LCHF) impair prolonged exercise performance during strenuous exercise by comparing it with high-carbohydrate diets in competitive triathletes. After 6-wk diet adaptation, time-to-exhaustion (TTE) performance was similar across both diets. Minimal carbohydrate supplementation (10 g/h) during exercise eliminated exercise-induced hypoglycemia and improved TTE by 22% on both diets. These findings suggest that LCHF diets do not impair exercise performance and require a 4-wk adaptation period for metabolic homeostasis.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C710-C727"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142942637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}