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Peng L, Guangshi L, Wusman LB, Tao L. STK16 promoted colorectal cancer progress in a c-MYC signaling-dependent manner. Mol Med 2024; 30:50. [PMID: 38622518 PMCID: PMC11020453 DOI: 10.1186/s10020-024-00816-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 04/01/2024] [Indexed: 04/17/2024] Open
Abstract
BACKGROUND Colorectal cancer standed as a global health challenge, ranking third in cancer incidence and second in cancer-related deaths worldwide. A deeper understanding of the intricate mechanisms driving colorectal cancer development was pressing need. STK16 had garnered attention in recent researches, while its involvement in cancer had been minimally explored. c-MYC had emerged as a key player in cancer biology. Due to its complex structure, multifunctionality, and intricate interactions, directly inhibiting the activity of c-MYC proves to be challenging. Hence, current research was directing efforts towards modulating c-MYC expression levels. METHODS Immunoblot, Immunohistochemistry and immunoprecipitation assays were conducted to assess the indicated protein expression levels. RT-PCR was performed to detect the corresponding mRNA expression levels. The proliferation, migration, invasion, and colony formation abilities of the specified cancer cells were investigated using CCK8 assays, Brdu assays, transwell assays, and colony formation assays, respectively. Cellular and animal experiments were performed to investigate the correlation between STK16 signaling and c-MYC signaling. RESULTS STK16 plays a positive regulatory role in the progression of colorectal cancer. Delving into the molecular mechanisms, we unveiled that STK16 phosphorylated c-MYC at serine 452, a pivotal event hindering the ubiquitin-proteasome pathway degradation of c-MYC. Importantly, colorectal cancer proliferation mediated by STK16 was found to be dependent on the phosphorylation of c-MYC at S452. Furthermore, the researchers demonstrated that STK16 knockout or pharmacological inhibition significantly curtailed colorectal cancer proliferation and c-MYC expression in in vivo animal models. CONCLUSION We discovered that STK16 phosphorylates c-MYC at serine 452, hindering its degradation via the ubiquitin-proteasome pathway. STK16 inhibition, either genetically or pharmacologically, effectively curtails cancer growth and c-MYC expression in vivo. These findings highlight STK16 as a potential therapeutic target for colorectal cancer.
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Affiliation(s)
- Li Peng
- Gastrointestinal Surgery department, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi City, Xinjiang Province, China
| | - Liu Guangshi
- Gastrointestinal Surgery department, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi City, Xinjiang Province, China
| | - Lai Bijiang Wusman
- Gastrointestinal Surgery department, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi City, Xinjiang Province, China
| | - Li Tao
- Gastrointestinal Surgery department, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi City, Xinjiang Province, China.
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Deprez MA, Caligaris M, Rosseels J, Hatakeyama R, Ghillebert R, Sampaio-Marques B, Mudholkar K, Eskes E, Meert E, Ungermann C, Ludovico P, Rospert S, De Virgilio C, Winderickx J. The nutrient-responsive CDK Pho85 primes the Sch9 kinase for its activation by TORC1. PLoS Genet 2023; 19:e1010641. [PMID: 36791155 PMCID: PMC9974134 DOI: 10.1371/journal.pgen.1010641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 02/28/2023] [Accepted: 01/27/2023] [Indexed: 02/16/2023] Open
Abstract
Yeast cells maintain an intricate network of nutrient signaling pathways enabling them to integrate information on the availability of different nutrients and adjust their metabolism and growth accordingly. Cells that are no longer capable of integrating this information, or that are unable to make the necessary adaptations, will cease growth and eventually die. Here, we studied the molecular basis underlying the synthetic lethality caused by loss of the protein kinase Sch9, a key player in amino acid signaling and proximal effector of the conserved growth-regulatory TORC1 complex, when combined with either loss of the cyclin-dependent kinase (CDK) Pho85 or loss of its inhibitor Pho81, which both have pivotal roles in phosphate sensing and cell cycle regulation. We demonstrate that it is specifically the CDK-cyclin pair Pho85-Pho80 or the partially redundant CDK-cyclin pairs Pho85-Pcl6/Pcl7 that become essential for growth when Sch9 is absent. Interestingly, the respective three CDK-cyclin pairs regulate the activity and distribution of the phosphatidylinositol-3 phosphate 5-kinase Fab1 on endosomes and vacuoles, where it generates phosphatidylinositol-3,5 bisphosphate that serves to recruit both TORC1 and its substrate Sch9. In addition, Pho85-Pho80 directly phosphorylates Sch9 at Ser726, and to a lesser extent at Thr723, thereby priming Sch9 for its subsequent phosphorylation and activation by TORC1. The TORC1-Sch9 signaling branch therefore integrates Pho85-mediated information at different levels. In this context, we also discovered that loss of the transcription factor Pho4 rescued the synthetic lethality caused by loss of Pho85 and Sch9, indicating that both signaling pathways also converge on Pho4, which appears to be wired to a feedback loop involving the high-affinity phosphate transporter Pho84 that fine-tunes Sch9-mediated responses.
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Affiliation(s)
- Marie-Anne Deprez
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Marco Caligaris
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Joëlle Rosseels
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Riko Hatakeyama
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Ruben Ghillebert
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Braga/Guimarães, Braga, Portugal
| | - Kaivalya Mudholkar
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Elja Eskes
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Els Meert
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Christian Ungermann
- Department of Biology/Chemistry & Center of Cellular Nanoanalytics (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Braga/Guimarães, Braga, Portugal
| | - Sabine Rospert
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail: (CDV); (JW)
| | - Joris Winderickx
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
- * E-mail: (CDV); (JW)
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Yeast cell death pathway requiring AP-3 vesicle trafficking leads to vacuole/lysosome membrane permeabilization. Cell Rep 2022; 39:110647. [PMID: 35417721 PMCID: PMC9074372 DOI: 10.1016/j.celrep.2022.110647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/17/2022] [Accepted: 03/16/2022] [Indexed: 12/24/2022] Open
Abstract
Unicellular eukaryotes have been suggested as undergoing self-inflicted destruction. However, molecular details are sparse compared with the mechanisms of programmed/regulated cell death known for human cells and animal models. Here, we report a molecular cell death pathway in Saccharomyces cerevisiae leading to vacuole/lysosome membrane permeabilization. Following a transient cell death stimulus, yeast cells die slowly over several hours, consistent with an ongoing molecular dying process. A genome-wide screen for death-promoting factors identified all subunits of the AP-3 complex, a vesicle trafficking adapter known to transport and install newly synthesized proteins on the vacuole/lysosome membrane. To promote cell death, AP-3 requires its Arf1-GTPase-dependent vesicle trafficking function and the kinase Yck3, which is selectively transported to the vacuole membrane by AP-3. Video microscopy revealed a sequence of events where vacuole permeability precedes the loss of plasma membrane integrity. AP-3-dependent death appears to be conserved in the human pathogenic yeast Cryptococcus neoformans. Details about how mammalian cells die have yielded effective cancer therapies. Similarly, details about fungal cell death may explain failed responses to anti-fungal agents and inform next-generation anti-fungal strategies. Stolp et al. describe a potential mechanism of yeast cell death subversion, by inhibiting AP-3 vesicle trafficking to block vacuole/lysosome permeability.
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