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Wang H, Ma B, Stevens T, Knapp J, Lu J, Prochownik EV. MYC Binding Near Transcriptional End Sites Regulates Basal Gene Expression, Read-Through Transcription and Intragenic Contacts. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.603118. [PMID: 39071289 PMCID: PMC11275772 DOI: 10.1101/2024.07.11.603118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
The MYC oncoprotein regulates numerous genes involved in cellular processes such as cell cycle and mitochondrial and ribosomal structure and function. This requires heterodimerization with its partner, MAX, and binding to specific promoter and enhancer elements. Here, we show that MYC and MAX also bind near transcriptional end sites (TESs) of over one-sixth of all annotated genes. These interactions are dose-dependent, evolutionarily conserved, stabilize the normally short-lived MYC protein and regulate expression both in concert with and independent of MYC's binding elsewhere. MYC's TES binding occurs in association with other transcription factors, alters the chromatin landscape, increases nuclease susceptibility and can alter transcriptional read-through, particularly in response to certain stresses. MYC-bound TESs can directly contact promoters and may fine-tune gene expression in response to both physiologic and pathologic stimuli. Collectively, these findings support a previously unrecognized role for MYC in regulating transcription and its read-through via direct intragenic contacts between TESs and promoters.
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Wang H, Stevens T, Lu J, Roberts A, Van't Land C, Muzumdar R, Gong Z, Vockley J, Prochownik EV. Body-Wide Inactivation of the Myc-Like Mlx Transcription Factor Network Accelerates Aging and Increases the Lifetime Cancer Incidence. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2401593. [PMID: 38976573 DOI: 10.1002/advs.202401593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 06/08/2024] [Indexed: 07/10/2024]
Abstract
The "Mlx" and "Myc" transcription factor networks cross-communicate and share many common gene targets. Myc's activity depends upon its heterodimerization with Max, whereas the Mlx Network requires that the Max-like factor Mlx associate with the Myc-like factors MondoA or ChREBP. The current work demonstrates that body-wide Mlx inactivation, like that of Myc, accelerates numerous aging-related phenotypes pertaining to body habitus and metabolism. The deregulation of numerous aging-related Myc target gene sets is also accelerated. Among other functions, these gene sets often regulate ribosomal and mitochondrial structure and function, genomic stability, and aging. Whereas "MycKO" mice have an extended lifespan because of a lower cancer incidence, "MlxKO" mice have normal lifespans and a higher cancer incidence. Like Myc, the expression of Mlx, MondoA, and ChREBP and their control over their target genes deteriorate with age in both mice and humans. Collectively, these findings underscore the importance of lifelong and balanced cross-talk between the two networks to maintain proper function and regulation of the many factors that can affect normal aging.
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Affiliation(s)
- Huabo Wang
- Division of Hematology/Oncology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Taylor Stevens
- Division of Hematology/Oncology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Jie Lu
- Division of Hematology/Oncology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Alexander Roberts
- Division of Hematology/Oncology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Clinton Van't Land
- Division of Medical Genetics, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Radhika Muzumdar
- Division of Endocrinology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Zhenwei Gong
- Division of Endocrinology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Jerry Vockley
- Division of Medical Genetics, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
| | - Edward V Prochownik
- Division of Hematology/Oncology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, 15201, USA
- The Department of Microbiology and Molecular Genetics, UPMC, Pittsburgh, PA, 15201, USA
- The Hillman Cancer Center of UPMC, 5115 Centre Ave, Pittsburgh, PA, 15232, USA
- The Pittsburgh Liver Research Center, UPMC, Pittsburgh, PA, 15224, USA
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3
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Li S, Wang Y, Yin J, Li K, Liu L, Gao J. Design, synthesis, and activity evaluation of 2-iminobenzimidazoles as c-Myc inhibitors for treating multiple myeloma. Heliyon 2024; 10:e28411. [PMID: 38590884 PMCID: PMC10999938 DOI: 10.1016/j.heliyon.2024.e28411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 03/18/2024] [Accepted: 03/18/2024] [Indexed: 04/10/2024] Open
Abstract
Multiple myeloma (MM) is a plasma cell malignancy that remains incurable and poses a significant threat to global public health. The multifunctional transcription factor c-Myc plays a crucial role in various cellular processes and is closely associated with MM progression. As part of the basic-helix-loop-helix-leucine zipper (bHLHZip) family, c-Myc forms heterodimers with its obligate partner Max, binds to the Enhancer-box (E-box) of DNA, and ultimately co-regulates gene expression. Therefore, impeding the capacity for heterodimerization to bind to DNA represents a favored strategy in thwarting c-Myc transcription. In this study, we first synthesized a series of novel 2-iminobenzimidazole derivatives and further estimated their potential anti-MM activity. Notably, among all the derivatives, 5b and 5d demonstrated remarkable inhibitory activity against RPMI-8226 and U266 cells, with IC50 values of 0.85 μM and 0.97 μM for compound 5b, and 0.96 μM and 0.89 μM for compound 5d. Western blot and dual-luciferase reporter assays demonstrated that compounds 5b and 5d effectively suppressed both c-Myc protein expression and transcriptional activity of the c-Myc promoter in RPMI-8226 and U266 cells. Furthermore, these compounds induced apoptosis and G1 cell cycle arrest in the aforementioned MM cells. Molecular docking studies revealed that 5b and 5d exhibited strong binding affinity to the interface between c-Myc/Max and E-box of DNA. Taken together, our findings suggest that further investigations are warranted for potential therapeutic applications of 5b and 5d for c-Myc-related diseases.
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Affiliation(s)
- Shihao Li
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, PR China
| | - Yinchuan Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, PR China
| | - Jiacheng Yin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, PR China
| | - Kaihang Li
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, PR China
| | - Linlin Liu
- College of Medical Imaging, Xuzhou Medical University, Xuzhou, Jiangsu 221004, PR China
| | - Jian Gao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, PR China
- School of Medicine, Anhui University of Science and Technology, Huainan, PR China
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Wang H, Stevens T, Lu J, Roberts A, Land CV, Muzumdar R, Gong Z, Vockley J, Prochownik EV. The Myc-Like Mlx Network Impacts Aging and Metabolism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.26.568749. [PMID: 38076995 PMCID: PMC10705233 DOI: 10.1101/2023.11.26.568749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The "Mlx" and "Myc" Networks share many common gene targets. Just as Myc's activity depends upon its heterodimerization with Max, the Mlx Network requires that the Max-like factor Mlx associate with the Myc-like factors MondoA or ChREBP. We show here that body-wide Mlx inactivation, like that of Myc, accelerates numerous aging-related phenotypes pertaining to body habitus and metabolism. The deregulation of numerous aging-related Myc target gene sets is also accelerated. Among other functions, these gene sets often regulate ribosomal and mitochondrial structure and function, genomic stability and aging. Whereas "MycKO" mice have an extended lifespan because of a lower cancer incidence, "MlxKO" mice have normal lifespans and a somewhat higher cancer incidence. Like Myc, Mlx, MondoA and ChREBP expression and that of their target genes, deteriorate with age in both mice and humans, underscoring the importance of life-long and balanced cross-talk between the two Networks to maintain normal aging.
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Affiliation(s)
- Huabo Wang
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh
| | - Taylor Stevens
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh
| | - Jie Lu
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh
| | - Alexander Roberts
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh
| | | | - Radhika Muzumdar
- Division of Endocrinology, UPMC Children’s Hospital of Pittsburgh
| | - Zhenwei Gong
- Division of Endocrinology, UPMC Children’s Hospital of Pittsburgh
| | - Jerry Vockley
- Division of Medical Genetics, UPMC Children’s Hospital of Pittsburgh
| | - Edward V. Prochownik
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh
- The Department of Microbiology and Molecular Genetics, UPMC
- The Hillman Cancer Center of UPMC
- The Pittsburgh Liver Research Center, UPMC, Pittsburgh, PA. 15224
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5
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Liu F, Liao Z, Zhang Z. MYC in liver cancer: mechanisms and targeted therapy opportunities. Oncogene 2023; 42:3303-3318. [PMID: 37833558 DOI: 10.1038/s41388-023-02861-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023]
Abstract
MYC, a major oncogenic transcription factor, regulates target genes involved in various pathways such as cell proliferation, metabolism and immune evasion, playing a critical role in the tumor initiation and development in multiple types of cancer. In liver cancer, MYC and its signaling pathways undergo significant changes, exerting a profound impact on liver cancer progression, including tumor proliferation, metastasis, dedifferentiation, metabolism, immune microenvironment, and resistance to comprehensive therapies. This makes MYC an appealing target, despite it being previously considered an undruggable protein. In this review, we discuss the role and mechanisms of MYC in liver physiology, chronic liver diseases, hepatocarcinogenesis, and liver cancer progression, providing a theoretical basis for targeting MYC as an ideal therapeutic target for liver cancer. We also summarize and prospect the strategies for targeting MYC, including direct and indirect approaches to abolish the oncogenic function of MYC in liver cancer.
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Affiliation(s)
- Furong Liu
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Hubei Key Laboratory of Hepato-Pancreato-Biliary Diseases, Wuhan, Hubei, 430030, China
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
| | - Zhibin Liao
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Hubei Key Laboratory of Hepato-Pancreato-Biliary Diseases, Wuhan, Hubei, 430030, China
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
| | - Zhanguo Zhang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.
- Hubei Key Laboratory of Hepato-Pancreato-Biliary Diseases, Wuhan, Hubei, 430030, China.
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China.
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García-Caballero D, Hart JR, Vogt PK. Long Non-Coding RNAs as "MYC Facilitators". PATHOPHYSIOLOGY 2023; 30:389-399. [PMID: 37755396 PMCID: PMC10534484 DOI: 10.3390/pathophysiology30030030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 09/28/2023] Open
Abstract
In this article, we discuss a class of MYC-interacting lncRNAs (long non-coding RNAs) that share the following criteria: They are direct transcriptional targets of MYC. Their expression is coordinated with the expression of MYC. They are required for sustained MYC-driven cell proliferation, and they are not essential for cell survival. We refer to these lncRNAs as "MYC facilitators" and discuss two representative members of this class of lncRNAs, SNHG17 (small nuclear RNA host gene) and LNROP (long non-coding regulator of POU2F2). We also present a general hypothesis on the role of lncRNAs in MYC-mediated transcriptional regulation.
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Affiliation(s)
| | | | - Peter K. Vogt
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Prochownik EV, Wang H. Lessons in aging from Myc knockout mouse models. Front Cell Dev Biol 2023; 11:1244321. [PMID: 37621775 PMCID: PMC10446843 DOI: 10.3389/fcell.2023.1244321] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023] Open
Abstract
Despite MYC being among the most intensively studied oncogenes, its role in normal development has not been determined as Myc-/- mice do not survival beyond mid-gestation. Myc ± mice live longer than their wild-type counterparts and are slower to accumulate many age-related phenotypes. However, Myc haplo-insufficiency likely conceals other important phenotypes as many high-affinity Myc targets genes continue to be regulated normally. By delaying Myc inactivation until after birth it has recently been possible to study the consequences of its near-complete total body loss and thus to infer its normal function. Against expectation, these "MycKO" mice lived significantly longer than control wild-type mice but manifested a marked premature aging phenotype. This seemingly paradoxical behavior was potentially explained by a >3-fold lower lifetime incidence of cancer, normally the most common cause of death in mice and often Myc-driven. Myc loss accelerated the accumulation of numerous "Aging Hallmarks", including the loss of mitochondrial and ribosomal structural and functional integrity, the generation of reactive oxygen species, the acquisition of genotoxic damage, the detrimental rewiring of metabolism and the onset of senescence. In both mice and humans, normal aging in many tissues was accompaniued by the downregulation of Myc and the loss of Myc target gene regulation. Unlike most mouse models of premature aging, which are based on monogenic disorders of DNA damage recognition and repair, the MycKO mouse model directly impacts most Aging Hallmarks and may therefore more faithfully replicate the normal aging process of both mice and humans. It further establishes that the strong association between aging and cancer can be genetically separated and is maintained by a single gene.
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Affiliation(s)
- Edward V. Prochownik
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States
- The Department of Microbiology and Molecular Genetics, UPMC, Pittsburgh, PA, United States
- The Hillman Cancer Center of UPMC, Pittsburgh, PA, United States
- The Pittsburgh Liver Research Center, UPMC, Pittsburgh, PA, United States
| | - Huabo Wang
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States
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Xin S, Liu X, Li Z, Sun X, Wang R, Zhang Z, Feng X, Jin L, Li W, Tang C, Mei W, Cao Q, Wang H, Zhang J, Feng L, Ye L. ScRNA-seq revealed an immunosuppression state and tumor microenvironment heterogeneity related to lymph node metastasis in prostate cancer. Exp Hematol Oncol 2023; 12:49. [PMID: 37221625 PMCID: PMC10204220 DOI: 10.1186/s40164-023-00407-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 04/25/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Metastasis is a crucial aspect of disease progression leading to death in patients with prostate cancer (PCa). However, its mechanism remains unclear. We aimed to explore the mechanism of lymph node metastasis (LNM) by analyzing the heterogeneity of tumor microenvironment (TME) in PCa using scRNA-seq. METHODS A total of 32,766 cells were obtained from four PCa tissue samples for scRNA-seq, annotated, and grouped. InferCNV, GSVA, DEG functional enrichment analysis, trajectory analysis, intercellular network evaluation, and transcription factor analysis were carried out for each cell subgroup. Furthermore, validation experiments targeting luminal cell subgroups and CXCR4 + fibroblast subgroup were performed. RESULTS The results showed that only EEF2 + and FOLH1 + luminal subgroups were present in LNM, and they appeared at the initial stage of luminal cell differentiation, which were comfirmed by verification experiments. The MYC pathway was enriched in the EEF2 + and FOLH1 + luminal subgroups, and MYC was associated with PCa LNM. Moreover, MYC did not only promote the progression of PCa, but also led to immunosuppression in TME by regulating PDL1 and CD47. The proportion of CD8 + T cells in TME and among NK cells and monocytes was lower in LNM than in the primary lesion, while the opposite was true for Th and Treg cells. Furthermore, these immune cells in TME underwent transcriptional reprogramming, including CD8 + T subgroups of CCR7 + and IL7R+, as well as M2-like monocyte subgroups expressing tumor-associated signature genes, like CCR7, SGKI, and RPL31. Furthermore, STEAP4+, ADGRF5 + and CXCR4+, and SRGNC + fibroblast subgroups were closely related to tumor progression, tumor metabolism, and immunosuppression, indicating their contributions in PCa metastasis. Meanwhile, The presence of CXCR4 + Fibroblasts in PCa was confirmed by polychromatic immunofluorescence. CONCLUSIONS The significant heterogeneity of luminal, immune, and interstitial cells in PCa LNM may not only directly contribute to tumor progression, but also indirectly result in TME immunosuppression, which may be the cause of metastasis in PCa and in which MYC played an role.
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Affiliation(s)
- Shiyong Xin
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
- Department of Urology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, 471003, China
| | - Xiang Liu
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
- Department of Urology, Putuo People's Hospital, School of Medicine, Shanghai, China
| | - Ziyao Li
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
| | - Xianchao Sun
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
| | - Rong Wang
- School of Pharmacy, Inner Mongolia Medical University, Hohhot, 010000, China
| | - Zhenhua Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Xinwei Feng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Liang Jin
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
| | - Weiyi Li
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
| | - Chaozhi Tang
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
| | - Wangli Mei
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China
| | - Qiong Cao
- Department of Pathology, The Third Affiliated Hospital of Henan University of Science and Technology, Henan, 471003, China
| | - Haojie Wang
- Department of Central Laboratory, Zhengzhou University, Luoyang Central Hospital, Luoyang, 471003, China
| | - Jianguo Zhang
- Department of Urology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, 471003, China
| | - Lijin Feng
- Department of Pathology, Jing'an District Zhabei Central Hospital, No.619, Zhonghuaxin Road, Shanghai, 200070, China.
| | - Lin Ye
- Department of Urology, Shanghai East Hospital, School of Medicine, Tongji University, No.150, Ji-mo Rd, Pu-dong new District, Shanghai, 200120, China.
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Wang H, Stevens T, Lu J, Airik M, Airik R, Prochownik EV. Disruption of Multiple Overlapping Functions Following Stepwise Inactivation of the Extended Myc Network. Cells 2022; 11:4087. [PMID: 36552851 PMCID: PMC9777503 DOI: 10.3390/cells11244087] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Myc, a member of the "Myc Network" of bHLH-ZIP transcription factors, supervises proliferation, metabolism, and translation. It also engages in crosstalk with the related "Mlx Network" to co-regulate overlapping genes and functions. We investigated the consequences of stepwise conditional inactivation of Myc and Mlx in primary and SV40 T-antigen-immortalized murine embryonic fibroblasts (MEFs). Myc-knockout (MycKO) and Myc × Mlx "double KO" (DKO)-but not MlxKO-primary MEFs showed rapid growth arrest and displayed features of accelerated aging and senescence. However, DKO MEFs soon resumed proliferating, indicating that durable growth arrest requires an intact Mlx network. All three KO MEF groups deregulated multiple genes and functions pertaining to aging, senescence, and DNA damage recognition/repair. Immortalized KO MEFs proliferated in Myc's absence while demonstrating variable degrees of widespread genomic instability and sensitivity to genotoxic agents. Finally, compared to primary MycKO MEFs, DKO MEFs selectively downregulated numerous gene sets associated with the p53 and retinoblastoma (Rb) pathways and G2/M arrest. Thus, the reversal of primary MycKO MEF growth arrest by either Mlx loss or SV40 T-antigen immortalization appears to involve inactivation of the p53 and/or Rb pathways.
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Affiliation(s)
- Huabo Wang
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Taylor Stevens
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Jie Lu
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Merlin Airik
- Division of Nephrology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Rannar Airik
- Division of Nephrology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
- Department of Developmental Biology, The University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Edward V. Prochownik
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
- The Department of Microbiology and Molecular Genetics, The University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
- The UPMC Hillman Comprehensive Cancer Center, Pittsburgh, PA 25232, USA
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA 15261, USA
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10
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Regulation of Normal and Neoplastic Proliferation and Metabolism by the Extended Myc Network. Cells 2022; 11:cells11243974. [PMID: 36552737 PMCID: PMC9777120 DOI: 10.3390/cells11243974] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
The Myc Network, comprising a small assemblage of bHLH-ZIP transcription factors, regulates many hundreds to thousands of genes involved in proliferation, energy metabolism, translation and other activities. A structurally and functionally related set of factors known as the Mlx Network also supervises some of these same functions via the regulation of a more limited but overlapping transcriptional repertoire. Target gene co-regulation by these two Networks is the result of their sharing of three members that suppress target gene expression as well as by the ability of both Network's members to cross-bind one another's consensus DNA sites. The two Networks also differ in that the Mlx Network's control over transcription is positively regulated by several glycolytic pathway intermediates and other metabolites. These distinctive properties, functions and tissue expression patterns potentially allow for sensitive control of gene regulation in ways that are differentially responsive to environmental and metabolic cues while allowing for them to be both rapid and of limited duration. This review explores how such control might occur. It further discusses how the actual functional dependencies of the Myc and Mlx Networks rely upon cellular context and how they may differ between normal and neoplastic cells. Finally, consideration is given to how future studies may permit a more refined understanding of the functional interrelationships between the two Networks.
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11
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Polyphenon E Effects on Gene Expression in PC-3 Prostate Cancer Cells. Int J Mol Sci 2022; 23:ijms232214328. [PMID: 36430806 PMCID: PMC9697490 DOI: 10.3390/ijms232214328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/22/2022] Open
Abstract
Polyphenon E (Poly E) is a standardized, caffeine-free green tea extract with defined polyphenol content. Poly E is reported to confer chemoprotective activity against prostate cancer (PCa) progression in the TRAMP model of human PCa, and has shown limited activity against human PCa in human trials. The molecular mechanisms of the observed Poly E chemopreventive activity against PCa are not fully understood. We hypothesized that Poly E treatment of PCa cells induces gene expression changes, which could underpin the molecular mechanisms of the limited Poly E chemoprevention activity against PCa. PC-3 cells were cultured in complete growth media supplemented with varied Poly E concentrations for 24 h, then RNA was isolated for comparative DNA microarray (0 vs. 200 mg/L Poly E) and subsequent TaqMan qRT-PCR analyses. Microarray data for 54,613 genes were filtered for >2-fold expression level changes, with 8319 genes increased and 6176 genes decreased. Eight genes involved in key signaling or regulatory pathways were selected for qRT-PCR. Two genes increased expression significantly, MXD1 (13.98-fold; p = 0.0003) and RGS4 (21.98-fold; p = 0.0011), by qRT-PCR. MXD1 and RGS4 significantly increased gene expression in Poly E-treated PC-3 cells, and the MXD1 gene expression increases were Poly E dose-dependent.
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12
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Wang H, Lu J, Alencastro F, Roberts A, Fiedor J, Carroll P, Eisenman RN, Ranganathan S, Torbenson M, Duncan AW, Prochownik EV. Coordinated Cross-Talk Between the Myc and Mlx Networks in Liver Regeneration and Neoplasia. Cell Mol Gastroenterol Hepatol 2022; 13:1785-1804. [PMID: 35259493 PMCID: PMC9046243 DOI: 10.1016/j.jcmgh.2022.02.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND & AIMS The c-Myc (Myc) Basic helix-loop-helix leucine zipper (bHLH-ZIP) transcription factor is deregulated in most cancers. In association with Max, Myc controls target genes that supervise metabolism, ribosome biogenesis, translation, and proliferation. This Myc network crosstalks with the Mlx network, which consists of the Myc-like proteins MondoA and ChREBP, and Max-like Mlx. Together, this extended Myc network regulates both common and distinct gene targets. Here, we studied the consequence of Myc and/or Mlx ablation in the liver, particularly those pertaining to hepatocyte proliferation, metabolism, and spontaneous tumorigenesis. METHODS We examined the ability of hepatocytes lacking Mlx (MlxKO) or Myc+Mlx (double KO [DKO]) to repopulate the liver over an extended period of time in a murine model of type I tyrosinemia. We also compared this and other relevant behaviors, phenotypes, and transcriptomes of the livers with those from previously characterized MycKO, ChrebpKO, and MycKO × ChrebpKO mice. RESULTS Hepatocyte regenerative potential deteriorated as the Extended Myc Network was progressively dismantled. Genes and pathways dysregulated in MlxKO and DKO hepatocytes included those pertaining to translation, mitochondrial function, and hepatic steatosis resembling nonalcoholic fatty liver disease. The Myc and Mlx Networks were shown to crosstalk, with the latter playing a disproportionate role in target gene regulation. All cohorts also developed steatosis and molecular evidence of early steatohepatitis. Finally, MlxKO and DKO mice showed extensive hepatic adenomatosis. CONCLUSIONS In addition to showing cooperation between the Myc and Mlx Networks, this study showed the latter to be more important in maintaining proliferative, metabolic, and translational homeostasis, while concurrently serving as a suppressor of benign tumorigenesis. GEO accession numbers: GSE181371, GSE130178, and GSE114634.
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Affiliation(s)
- Huabo Wang
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Jie Lu
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Frances Alencastro
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; McGowan Institute for Regenerative Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Alexander Roberts
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Julia Fiedor
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Patrick Carroll
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Robert N Eisenman
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | | | - Michael Torbenson
- Department of Laboratory Medicine and Pathology, The Mayo Clinic, Rochester, Minnesota
| | - Andrew W Duncan
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; McGowan Institute for Regenerative Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Edward V Prochownik
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania; Hillman Comprehensive Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; Department of Microbiology and Molecular Genetics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
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