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Sarwar MS, Ramirez CN, Kuo HCD, Chou P, Wu R, Sargsyan D, Yang Y, Shannar A, Peter RM, Yin R, Wang Y, Su X, Kong AN. Triterpenoid ursolic acid regulates the environmental carcinogen benzo[a]pyrene-driven epigenetic and metabolic alterations in SKH-1 hairless mice for skin cancer interception. Carcinogenesis 2024; 45:288-299. [PMID: 38466106 PMCID: PMC11102768 DOI: 10.1093/carcin/bgae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/25/2024] [Accepted: 03/09/2024] [Indexed: 03/12/2024] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental carcinogens accountable to developing skin cancers. Recently, we reported that exposure to benzo[a]pyrene (B[a]P), a common PAH, causes epigenetic and metabolic alterations in the initiation, promotion and progression of non-melanoma skin cancer (NMSC). As a follow-up investigation, this study examines how dietary triterpenoid ursolic acid (UA) regulates B[a]P-driven epigenetic and metabolic pathways in SKH-1 hairless mice. Our results show UA intercepts against B[a]P-induced tumorigenesis at different stages of NMSC. Epigenomic cytosines followed by guanine residues (CpG) methyl-seq data showed UA diminished B[a]P-mediated differentially methylated regions (DMRs) profiles. Transcriptomic RNA-seq revealed UA revoked B[a]P-induced differentially expressed genes (DEGs) of skin cancer-related genes, such as leucine-rich repeat LGI family member 2 (Lgi2) and kallikrein-related peptidase 13 (Klk13), indicating UA plays a vital role in B[a]P-mediated gene regulation and its potential consequences in NMSC interception. Association analysis of DEGs and DMRs found that the mRNA expression of KLK13 gene was correlated with the promoter CpG methylation status in the early-stage comparison group, indicating UA could regulate the KLK13 by modulating its promoter methylation at an early stage of NMSC. The metabolomic study showed UA alters B[a]P-regulated cancer-associated metabolisms like thiamin metabolism, ascorbate and aldarate metabolism during the initiation phase; pyruvate, citrate and thiamin metabolism during the promotion phase; and beta-alanine and pathothenate coenzyme A (CoA) biosynthesis during the late progression phase. Taken together, UA reverses B[a]P-driven epigenetic, transcriptomic and metabolic reprogramming, potentially contributing to the overall cancer interception against B[a]P-mediated NMSC.
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Affiliation(s)
- Md Shahid Sarwar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Christina N Ramirez
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Hsiao-Chen Dina Kuo
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Pochung Chou
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Renyi Wu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Davit Sargsyan
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Yuqing Yang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ahmad Shannar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Rebecca Mary Peter
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ran Yin
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Yujue Wang
- Metabolomics Shared Resource, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901, USA
| | - Xiaoyang Su
- Metabolomics Shared Resource, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901, USA
| | - Ah-Ng Kong
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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Takashima S, Sun W, Otten ABC, Cai P, Peng SI, Tong E, Bui J, Mai M, Amarbayar O, Cheng B, Odango RJ, Li Z, Qu K, Sun BK. Alternative mRNA splicing events and regulators in epidermal differentiation. Cell Rep 2024; 43:113814. [PMID: 38402585 PMCID: PMC11293371 DOI: 10.1016/j.celrep.2024.113814] [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: 04/21/2023] [Revised: 08/22/2023] [Accepted: 02/01/2024] [Indexed: 02/27/2024] Open
Abstract
Alternative splicing (AS) of messenger RNAs occurs in ∼95% of multi-exon human genes and generates diverse RNA and protein isoforms. We investigated AS events associated with human epidermal differentiation, a process crucial for skin function. We identified 6,413 AS events, primarily involving cassette exons. We also predicted 34 RNA-binding proteins (RBPs) regulating epidermal AS, including 19 previously undescribed candidate regulators. From these results, we identified FUS as an RBP that regulates the balance between keratinocyte proliferation and differentiation. Additionally, we characterized the function of a cassette exon AS event in MAP3K7, which encodes a kinase involved in cell signaling. We found that a switch from the short to long isoform of MAP3K7, triggered during differentiation, enforces the demarcation between proliferating basal progenitors and overlying differentiated strata. Our findings indicate that AS occurs extensively in the human epidermis and has critical roles in skin homeostasis.
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Affiliation(s)
- Shota Takashima
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Wujianan Sun
- Department of Oncology, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Auke B C Otten
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Pengfei Cai
- Department of Oncology, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Shaohong Isaac Peng
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Elton Tong
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Jolina Bui
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - McKenzie Mai
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Oyumergen Amarbayar
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Binbin Cheng
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Rowen Jane Odango
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA
| | - Zongkai Li
- Department of Oncology, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Kun Qu
- Department of Oncology, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Bryan K Sun
- Department of Dermatology, University of California San Diego, La Jolla, CA 92109, USA.
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da Silva AM, Yevdokimova V, Benoit YD. Sam68 is a druggable vulnerability point in cancer stem cells. Cancer Metastasis Rev 2024; 43:441-456. [PMID: 37792222 PMCID: PMC11016129 DOI: 10.1007/s10555-023-10145-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 09/27/2023] [Indexed: 10/05/2023]
Abstract
Sam68 (Src associated in mitosis of 68 kDa) is an RNA-binding and multifunctional protein extensively characterized in numerous cellular functions, such as RNA processing, cell cycle regulation, kinase- and growth factor signaling. Recent investigations highlighted Sam68 as a primary target of a class of reverse-turn peptidomimetic drugs, initially developed as inhibitors of Wnt/β-catenin mediated transcription. Further investigations on such compounds revealed their capacity to selectively eliminate cancer stem cell (CSC) activity upon engaging Sam68. This work highlighted previously unappreciated roles for Sam68 in the maintenance of neoplastic self-renewal and tumor-initiating functions. Here, we discuss the implication of Sam68 in tumorigenesis, where central findings support its contribution to chromatin regulation processes essential to CSCs. We also review advances in CSC-targeting drug discovery aiming to modulate Sam68 cellular distribution and protein-protein interactions. Ultimately, Sam68 constitutes a vulnerability point of CSCs and an attractive therapeutic target to impede neoplastic stemness in human tumors.
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Affiliation(s)
- Amanda Mendes da Silva
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Veronika Yevdokimova
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Yannick D Benoit
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
- School of Pharmaceutical Sciences, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
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George N, Bhandari P, Shruptha P, Jayaram P, Chaudhari S, Satyamoorthy K. Multidimensional outlook on the pathophysiology of cervical cancer invasion and metastasis. Mol Cell Biochem 2023; 478:2581-2606. [PMID: 36905477 PMCID: PMC10006576 DOI: 10.1007/s11010-023-04686-3] [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: 07/14/2022] [Accepted: 02/20/2023] [Indexed: 03/12/2023]
Abstract
Cervical cancer being one of the primary causes of high mortality rates among women is an area of concern, especially with ineffective treatment strategies. Extensive studies are carried out to understand various aspects of cervical cancer initiation, development and progression; however, invasive cervical squamous cell carcinoma has poor outcomes. Moreover, the advanced stages of cervical cancer may involve lymphatic circulation with a high risk of tumor recurrence at distant metastatic sites. Dysregulation of the cervical microbiome by human papillomavirus (HPV) together with immune response modulation and the occurrence of novel mutations that trigger genomic instability causes malignant transformation at the cervix. In this review, we focus on the major risk factors as well as the functionally altered signaling pathways promoting the transformation of cervical intraepithelial neoplasia into invasive squamous cell carcinoma. We further elucidate genetic and epigenetic variations to highlight the complexity of causal factors of cervical cancer as well as the metastatic potential due to the changes in immune response, epigenetic regulation, DNA repair capacity, and cell cycle progression. Our bioinformatics analysis on metastatic and non-metastatic cervical cancer datasets identified various significantly and differentially expressed genes as well as the downregulation of potential tumor suppressor microRNA miR-28-5p. Thus, a comprehensive understanding of the genomic landscape in invasive and metastatic cervical cancer will help in stratifying the patient groups and designing potential therapeutic strategies.
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Affiliation(s)
- Neena George
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Planetarium Complex, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Poonam Bhandari
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Planetarium Complex, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Padival Shruptha
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Planetarium Complex, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Pradyumna Jayaram
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Planetarium Complex, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Sima Chaudhari
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Planetarium Complex, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Planetarium Complex, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
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Yu X, Kang W, Zhang J, Chen C, Liu Y. Shortening of the KHDRBS1 3'UTR by alternative cleavage and polyadenylation alters miRNA-mediated regulation and promotes gastric cancer progression. Am J Transl Res 2022; 14:6574-6585. [PMID: 36247240 PMCID: PMC9556470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/05/2022] [Indexed: 06/16/2023]
Abstract
The shortening of the 3' untranslated regions (3'UTRs) due to alternative polyadenylation (APA) has become an important characteristic of cancer. However, the function of APA-induced 3'UTR shortening in gastric cancer (GC) remains unclear. KHDRBS1 (sam68), as an RNA-binding protein (RBP), is significantly upregulated in GC. In this study, we found that the 3'UTR of KHDRBS1 is generally shortened in GC tissues compared to paracancer tissues. Moreover, KHDRBS1 mRNA with a shortened 3'UTR can escape the inhibitory effect of miRNAs, resulting in its increased expression in GC. Overexpression of KHDRBS1, especially KHDRBS1 with a shortened 3'UTR, promotes the growth and metastasis of GC in vivo and in vitro. In conclusion, the experimental results show that shortening of the KHDRBS1 mRNA 3'UTR can mediate the overexpression of KHDRBS1 in GC cells and promote the progression of GC.
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Affiliation(s)
- Xin Yu
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University 218 Jixi Avenue, Hefei 230022, Anhui, China
| | - Weibiao Kang
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University 218 Jixi Avenue, Hefei 230022, Anhui, China
| | - Jiajia Zhang
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University 218 Jixi Avenue, Hefei 230022, Anhui, China
| | - Changyu Chen
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University 218 Jixi Avenue, Hefei 230022, Anhui, China
| | - Yi Liu
- Department of General Surgery, The First Affiliated Hospital of Anhui Medical University 218 Jixi Avenue, Hefei 230022, Anhui, China
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DNA Damage Regulates the Functions of the RNA Binding Protein Sam68 through ATM-Dependent Phosphorylation. Cancers (Basel) 2022; 14:cancers14163847. [PMID: 36010841 PMCID: PMC9405969 DOI: 10.3390/cancers14163847] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/26/2022] [Accepted: 08/05/2022] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Alterations of the complex network of interactions between the DNA damage response pathway and RNA metabolism have been described in several tumors, and increasing efforts are devoted to the elucidation of the molecular mechanisms involved in this network. Previous large-scale proteomic studies identified the RNA binding protein Sam68 as a putative target of the ATM kinase. Herein, we demonstrate that ATM phosphorylates Sam68 upon DNA damage induction, and this post-translational modification regulates both the signaling function of Sam68 in the initial phase of the DNA damage response and its RNA processing activity. Thus, our study uncovers anew crosstalk between ATM and Sam68, which may represent a paradigm for the functional interaction between the DDR pathway and RNA binding proteins, and a possible actionabletarget in human cancers. Abstract Cancer cells frequently exhibit dysregulation of the DNA damage response (DDR), genomic instability, and altered RNA metabolism. Recent genome-wide studies have strongly suggested an interaction between the pathways involved in the cellular response to DDR and in the regulation of RNA metabolism, but the molecular mechanism(s) involved in this crosstalk are largely unknown. Herein, we found that activation of the DDR kinase ATM promotes its interaction with Sam68, leading to phosphorylation of this multifunctional RNA binding protein (RBP) on three residues: threonine 61, serine 388 and serine 390. Moreover, we demonstrate that ATM-dependent phosphorylation of threonine 61 promotes the function of Sam68 in the DDR pathway and enhances its RNA processing activity. Importantly, ATM-mediated phosphorylation of Sam68 in prostate cancer cells modulates alternative polyadenylation of transcripts that are targets of Sam68, supporting the notion that the ATM–Sam68 axis exerts a multifaceted role in the response to DNA damage. Thus, our work validates Sam68 as an ATM kinase substrate and uncovers an unexpected bidirectional interplay between ATM and Sam68, which couples the DDR pathway to modulation of RNA metabolism in response to genotoxic stress.
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Zhang W, Liu L, Zhao S, Chen L, Wei Y, Chen W, Ge F. Research progress on RNA‑binding proteins in breast cancer (Review). Oncol Lett 2022; 23:121. [PMID: 35261635 PMCID: PMC8867207 DOI: 10.3892/ol.2022.13241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 02/03/2022] [Indexed: 11/28/2022] Open
Abstract
Breast cancer is the most common malignancy among women, and the abnormal regulation of gene expression serves an important role in its occurrence and development. However, the molecular mechanisms underlying gene expression are highly complex and heterogeneous, and RNA-binding proteins (RBPs) are among the key regulatory factors. RBPs bind targets in an environment-dependent or environment-independent manner to influence mRNA stability and the translation of genes involved in the formation, progression, metastasis and treatment of breast cancer. Due to the growing interest in these regulators, the present review summarizes the most influential studies concerning RBPs associated with breast cancer to elucidate the role of RBPs in breast cancer and to assess how they interact with other key pathways to provide new molecular targets for the diagnosis and treatment of breast cancer.
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Affiliation(s)
- Wenzhu Zhang
- Department of Breast Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
| | - Linlin Liu
- School of Forensic Medicine, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
| | - Shengdi Zhao
- Department of Breast Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
| | - Liang Chen
- Department of Breast Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
| | - Yuxian Wei
- Department of Endocrine Breast Surgery, First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Wenlin Chen
- Third Department of Breast Surgery, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, P.R. China
| | - Fei Ge
- Department of Breast Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
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Comparative O-GlcNAc Proteomic Analysis Reveals a Role of O-GlcNAcylated SAM68 in Lung Cancer Aggressiveness. Cancers (Basel) 2022; 14:cancers14010243. [PMID: 35008409 PMCID: PMC8749979 DOI: 10.3390/cancers14010243] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/19/2021] [Accepted: 12/30/2021] [Indexed: 01/25/2023] Open
Abstract
Simple Summary Lung cancer claims the most lives annually among cancers; to date, invasion and metastasis still pose challenges to effective treatment. O-GlcNAcylation, an enzymatic modification of proteins after biosynthesis, modulates the functions of many proteins. Aberrant O-GlcNAcylation is linked to pathogenic mechanisms of cancer, including invasion and metastasis. However, little is known about the profile of O-GlcNAcylated proteins involved in cancer aggressiveness. Here, by comparing profiles of O-GlcNAcylated proteins from two lung cancer cell lines different in their invasive potential, we identified candidates for O-GlcNAcylated proteins that may be involved in cancer aggressiveness. One of these candidates, SAM68, was further characterized. Results confirmed O-GlcNAcylation of SAM68; functional analyses on SAM68 with mutations at O-GlcNAcylation sites suggested a role of O-GlcNAcylated SAM68 in modulating lung cancer cell migration/invasion. Future elucidation of the functional significance of differential O-GlcNAcylation of proteins identified in this study may provide new insights into mechanisms of lung cancer progression. Abstract O-GlcNAcylation is a reversible and dynamic post-translational protein modification catalyzed by O-GlcNAc transferase (OGT). Despite the reported association of O-GlcNAcylation with cancer metastasis, the O-GlcNAc proteome profile for cancer aggressiveness remains largely uncharacterized. Here, we report our comparative O-GlcNAc proteome profiling of two differentially invasive lung adenocarcinoma cell lines, which identified 158 down-regulated and 106 up-regulated candidates in highly invasive cells. Among these differential proteins, a nuclear RNA-binding protein, SAM68 (SRC associated in mitosis of 68 kDa), was further investigated. Results showed that SAM68 is O-GlcNAcylated and may interact with OGT in the nucleus. Eleven O-GlcNAcylation sites were identified, and data from mutant analysis suggested that multiple serine residues in the N-terminal region are important for O-GlcNAcylation and the function of SAM68 in modulating cancer cell migration and invasion. Analysis of clinical specimens found that high SAM68 expression was associated with late cancer stages, and patients with high-OGT/high-SAM68 expression in their tumors had poorer overall survival compared to those with low-OGT/low-SAM68 expression. Our study revealed an invasiveness-associated O-GlcNAc proteome profile and connected O-GlcNAcylated SAM68 to lung cancer aggressiveness.
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Wang Y, Chen Y, Xiao S, Fu K. Integrated Analysis of the Functions and Prognostic Values of RNA-Binding Proteins in Colorectal Cancer. Front Cell Dev Biol 2020; 8:595605. [PMID: 33224957 PMCID: PMC7674310 DOI: 10.3389/fcell.2020.595605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/08/2020] [Indexed: 01/10/2023] Open
Abstract
Colorectal cancer (CRC) is one of the most common malignant tumors. Selecting effective treatment for CRC patients, especially in the early stages, remains a challenge because of the lack of adequate biomarkers. Recent evidence suggests that RNA-binding proteins (RBPs) play a vital role in development and progression of carcinogenesis. However, their mechanisms in cancer progression are still limited. The role of RBPs in CRC has been poorly understood. There were 1,542 reported RBPs analyzed between CRC tissues and normal tissues using the Wilcoxon test to identify differentially expressed RBPs (DE RBPs). Then, the potential functions and the prognostic value of these DE RBPs were explored through systematic bioinformatics analysis. There were 177 DE RBPs identified between CRC tissues and normal tissues. A protein–protein interaction network was constructed based on DE RBPs, and critical modules were screened. A regulatory network between prognostic DE RBPs and differentially expressed transcription factors was constructed. Besides, a risk signature was built based on prognostic DE RBPs, which is able to predict overall survival of CRC patients with high accuracy. In conclusion, the results provided a comprehensive understanding of the functions of RBPs in CRC, as well as an RBP-related prognostic signature.
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Affiliation(s)
- Ya Wang
- Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China.,Department of General Surgery, Xiangya Hospital, Central South University, Changsha, China
| | - Yuqiao Chen
- Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China.,Department of General Surgery, Xiangya Hospital, Central South University, Changsha, China
| | - Shuai Xiao
- Department of Gastrointestinal Surgery and Institute of Clinical Medicine, The First Affiliated Hospital, University of South China, Hengyang, China
| | - Kai Fu
- Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China.,Department of General Surgery, Xiangya Hospital, Central South University, Changsha, China.,Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, China
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10
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Zhao J, Li J, Hassan W, Xu D, Wang X, Huang Z. Sam68 promotes aerobic glycolysis in colorectal cancer by regulating PKM2 alternative splicing. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:459. [PMID: 32395503 PMCID: PMC7210197 DOI: 10.21037/atm.2020.03.108] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background Sam68, an RNA-binding protein, exerts oncogenic functions in several types of cancer. However, the specific functions and mechanisms of Sam68 in colorectal cancer (CRC) had not been previously clarified. Pyruvate kinase muscle (PKM)2 is the key rate-limiting enzyme in glycolysis, and PKM2 maintains the glycolysis-dominant energy metabolism in most cancer cells. Methods CCK8 assay was performed to show the effect of Sam68 on cell growth. Pyruvate kinase activity and lactate detection assays were performed to analyze the effects of Sam68 on aerobic glycolysis. RNA immunoprecipitation (RIP) was used to detect the binding of Sam68 to the PKM2 sequence. Western blot and real-time PCR were executed to analyze the regulation of PKM2 by Sam68. Results Gain-of-function and loss-of-function studies showed that ectopic expression of Sam68 promoted glycolysis and cell proliferation in CRC cells, whereas Sam68 knockdown inhibited glycolysis and cell proliferation. Mechanically, Sam68 modulated the expression profile of pyruvate kinase (PKM2 or PKM1) by regulating its alternative splicing. Overexpression of Sam68 was associated with decreased PKM1/PKM2 ratio, which positively contributed to the glycolysis procedure. Sam68 significantly promoted cell proliferation and caused a decrease of PKM1/PKM2 ratio, resulting in the metabolism of glucose switched from oxidative phosphorylation to glycolysis in CRC cells. Besides, Sam68 enhanced PKM2 mRNA transport from the nucleus to cytoplasm and increased the expression of PKM2 protein, resulting in elevated pyruvate kinase activity and lactate production. Conclusions These findings suggested that Sam68 affected cell growth and glycolysis pathway by regulating the alternative splicing and expression of PKM2 in CRC.
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Affiliation(s)
- Jing Zhao
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, Wuxi 214062, China.,Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi 214062, China
| | - Jiuming Li
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, Wuxi 214062, China.,Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi 214062, China
| | - Waseem Hassan
- Department of Pharmacy, COMSATS University Islamabad, Lahore Campus, Lahore, Pakistan
| | - Dongyan Xu
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi 214062, China
| | - Xue Wang
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi 214062, China
| | - Zhaohui Huang
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, Wuxi 214062, China
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11
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Fu K, Sun X, Xia X, Hobbs RP, Guo Y, Coulombe PA, Wan F. Sam68 is required for the growth and survival of nonmelanoma skin cancer. Cancer Med 2019; 8:6106-6113. [PMID: 31436046 PMCID: PMC6792479 DOI: 10.1002/cam4.2513] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/07/2019] [Accepted: 08/11/2019] [Indexed: 12/20/2022] Open
Abstract
Although targeting DNA repair signaling pathways has emerged as a promising therapeutic for skin cancer, the relevance of DNA damage responses (DDR) in the development and survival of nonmelanoma skin cancer (NMSC), the most common type of skin cancer, remains obscure. Here, we report that Src-associated substrate during mitosis of 68 kDa (Sam68), an early signaling molecule in DDR, is elevated in skin tumor tissues derived from NMSC patients and skin lesions from Gli2-transgenic mice. Downregulation of Sam68 impacts the growth and survival of human tumor keratinocytes and genetic ablation of Sam68 delays the onset of basal cell carcinomas (BCC) in Gli2-transgenic mice. Moreover, Sam68 plays a critical role in DNA damage-induced DNA repair and nuclear factor kappa B (NF-κB) signaling pathways in keratinocytes, hence conferring keratinocyte sensitivity to DNA damaging agents. Together, our data reveal a novel function of Sam68 in regulating DDR in keratinocytes that is crucial for the growth and survival of NMSC.
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Affiliation(s)
- Kai Fu
- Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Xin Sun
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,The Rockefeller University, New York, NY, USA
| | - Xue Xia
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Ryan P Hobbs
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Dermatology, College of Medicine, Pennsylvania State University, Hershey, PA, USA
| | - Yajuan Guo
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Dermatology, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Fengyi Wan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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