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He X, Yeung SJ, Esteva FJ. A new paradigm for classifying and treating HER2-positive breast cancer. Cancer Rep (Hoboken) 2023; 6:e1841. [PMID: 37254964 PMCID: PMC10432420 DOI: 10.1002/cnr2.1841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/10/2023] [Accepted: 05/22/2023] [Indexed: 06/01/2023] Open
Abstract
BACKGROUND Because of the phenomenal success of treatment with monoclonal antibodies and antibody-drug conjugates targeting human epidermal growth factor receptor 2 (HER2), most patients with early-stage HER2-positive breast cancer (HER2+ BC) and some with limited metastatic diseases have been cured, and those who have not been cured have achieved significant improvements in overall survival, which has weakened the role of the TNM staging system in the prognosis of HER2+ BC today. Given that the disease is now highly curable, treatment conception, classification, and modalities should differ from those of cancer types with a poor prognosis. It is warranted to build a new paradigm for classifying and treating HER2+ BC. RECENT FINDINGS In our personal view, we suggest that the classification system should be based not only on traditional anatomy and cancer biology but also on available treatment regimens, their exceptional outcomes, and their toxicities. In this regard, we developed a new concise classification of HER2+ BC based on the TNM staging system, a review of the literature, research results, and our clinical experience, dividing the patients into four distinct groups: curable (lymph-node negative and small (≤3 cm) early breast cancer), do our best to cure (locally advanced or tumors >3 cm early breast cancer), hope for cure (local-regional recurrent, limited metastases, and exceptional responders), and incurable (metastatic breast cancer with poor performance status or non-exceptional responders). CONCLUSION It will assist clinicians in developing an optimal treatment regimen at the outset, curing more HER2+ BC patients and improving their quality of life.
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Affiliation(s)
- Xuexin He
- Department of Medical OncologyHuashan Hospital of Fudan UniversityShanghaiChina
| | | | - Francisco J. Esteva
- Division of Hematology/OncologyNorthwell Health Cancer Institute at Lenox Hill HospitalNew YorkNew YorkUSA
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Xiong X, Ke X, Wang L, Lin Y, Wang S, Yao Z, Li K, Luo Y, Liu F, Pan Y, Yeung SJ, Helfrich W, Zhang H. Neoantigen-based cancer vaccination using chimeric RNA-loaded dendritic cell-derived extracellular vesicles. J Extracell Vesicles 2022; 11:e12243. [PMID: 35927827 PMCID: PMC9451527 DOI: 10.1002/jev2.12243] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 06/09/2022] [Accepted: 06/21/2022] [Indexed: 02/05/2023] Open
Abstract
Cancer vaccines critically rely on the availability of targetable immunogenic cancer-specific neoepitopes. However, mutation-based immunogenic neoantigens are rare or even non-existent in subgroups of cancer types. To address this issue, we exploited a cancer-specific aberrant transcription-induced chimeric RNA, designated A-Pas chiRNA, as a possible source of clinically relevant and targetable neoantigens. A-Pas chiRNA encodes a recently discovered cancer-specific chimeric protein that comprises full-length astrotactin-2 (ASTN2) C-terminally fused in-frame to the antisense sequence of the 18th intron of pregnancy-associated plasma protein-A (PAPPA). We used extracellular vesicles (EVs) from A-Pas chiRNA-transfected dendritic cells (DCs) to produce the cell-free anticancer vaccine DEXA-P . Treatment of immunocompetent cancer-bearing mice with DEXA-P inhibited tumour growth and prolonged animal survival. In summary, we demonstrate for the first time that cancer-specific transcription-induced chimeric RNAs can be exploited to produce a cell-free cancer vaccine that induces potent CD8+ T cell-mediated anticancer immunity. Our novel approach may be particularly useful for developing cancer vaccines to treat malignancies with low mutational burden or without mutation-based antigens. Moreover, this cell-free anticancer vaccine approach may offer several practical advantages over cell-based vaccines, such as ease of scalability and genetic modifiability as well as enhanced shelf life.
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Affiliation(s)
- Xiao Xiong
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Xiurong Ke
- Department of SurgeryLaboratory for Translational Surgical OncologyUniversity of GroningenUniversity Medical Center GroningenGroningenThe Netherlands
- Shantou University Medical CollegeShantouGuangdongChina
| | - Lu Wang
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Yusheng Lin
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
- Shantou University Medical CollegeShantouGuangdongChina
- Department of HematologyUniversity of GroningenUniversity Medical Center GroningenGroningenThe Netherlands
| | - Shuhong Wang
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Zhimeng Yao
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Kai Li
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Yichen Luo
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Fan Liu
- Institute of Precision Cancer Medicine and Pathology, and Department of PathologySchool of Medicineand Department of General SurgeryThe First Affiliated Hospital of Jinan UniversityJinan UniversityGuangzhouGuangdongChina
| | - Yunlong Pan
- Department of General SurgeryThe First Affiliated Hospital of Jinan University, and Institute of Precision Cancer Medicine and PathologySchool of MedicineJinan UniversityGuangzhouGuangdongChina
| | - Sai‐Ching J. Yeung
- Department of Emergency MedicineUniversity of Texas MD Anderson Cancer CenterHoustonTexasUSA
- Department of Endocrine Neoplasia and Hormonal DisordersUniversity of Texas MD Anderson Cancer CenterHoustonTexasUSA
| | - Wijnand Helfrich
- Department of SurgeryLaboratory for Translational Surgical OncologyUniversity of GroningenUniversity Medical Center GroningenGroningenThe Netherlands
| | - Hao Zhang
- Department of General SurgeryThe First Affiliated Hospital of Jinan University, and Institute of Precision Cancer Medicine and PathologySchool of MedicineJinan UniversityGuangzhouGuangdongChina
- Minister of Education Key Laboratory of Tumor Molecular BiologyJinan UniversityGuangzhouGuangdongChina
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Hudson MF, Strassels SA, Durham DD, Siddique S, Adler D, Yeung SJ, Bernstein SL, Baugh CW, Coyne CJ, Grudzen CR, Henning DJ, Klotz A, Madsen TE, Pallin DJ, Rico JF, Ryan RJ, Shapiro NI, Swor R, Venkat A, Wilson J, Thomas CR, Bischof JJ, Lyman GH, Caterino JM. Examining pain among non-Hispanic Black and non-Hispanic White patients with cancer visiting emergency departments: CONCERN (Comprehensive Oncologic Emergencies Research Network). Acad Emerg Med 2022; 29:364-368. [PMID: 34606137 DOI: 10.1111/acem.14395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 11/28/2022]
Affiliation(s)
| | - Scott A. Strassels
- Division of Pharmacy Atrium Health Charlotte North Carolina USA
- Department of Surgery The Ohio State University Columbus Ohio USA
| | - Danielle D. Durham
- Department of Radiology School of Medicine University of North Carolina Chapel Hill North Carolina USA
| | - Sunny Siddique
- Healthcare Delivery Research Program Division of Cancer Control and Population Sciences National Cancer Institute Rockville Maryland USA
| | - David Adler
- Department of Emergency Medicine University of Rochester Rochester New York USA
| | - Sai‐Ching J. Yeung
- Department of Emergency Medicine The University of Texas MD Anderson Cancer Center Houston Texas USA
| | - Steven L. Bernstein
- Department of Emergency Medicine Dartmouth Hitchcock Medical Center Hanover New Hampshire USA
| | - Christopher W. Baugh
- Department of Emergency Medicine Brigham and Women’s Hospital Boston Massachusetts USA
| | - Christopher J. Coyne
- Department of Emergency Medicine University of California San Diego San Diego California USA
| | - Corita R. Grudzen
- Ronald O. Perelman Department of Emergency Medicine and Population Health New York University School of Medicine New York New York USA
| | - Daniel J. Henning
- Department of Emergency Medicine University of Washington Seattle Washington USA
| | - Adam Klotz
- Department of Medicine Memorial Sloan Kettering Cancer Center New York New York USA
| | - Troy E. Madsen
- Division of Emergency Medicine University of Utah Salt Lake City, Utah USA
| | - Daniel J. Pallin
- Department of Emergency Medicine Brigham and Women’s Hospital Boston Massachusetts USA
| | - Juan F. Rico
- Department of Pediatrics University of South Florida Morsani College of Medicine Tampa Florida USA
| | - Richard J. Ryan
- Department of Emergency Medicine University of Cincinnati Cincinnati Ohio USA
| | - Nathan I. Shapiro
- Department of Emergency Medicine Beth Israel Deaconess Medical Center Boston Massachusetts USA
| | - Robert Swor
- Department of Emergency Medicine William Beaumont Hospital Royal Oak Michigan USA
| | - Arvind Venkat
- Department of Emergency Medicine Allegheny Health Network Pittsburgh Pennsylvania USA
| | - Jason Wilson
- Department of Emergency Medicine University of South Florida Morsani College of Medicine Tampa Florida USA
| | - Charles R. Thomas
- Department of Radiation Medicine Knight Cancer Institute Oregon Health & Sciences University Portland Oregon USA
| | - Jason J. Bischof
- Department of Emergency Medicine The Ohio State University, Wexner Medical Center Columbus Ohio USA
| | - Gary H. Lyman
- Hutchinson Institute for Cancer Outcomes Research, Fred Hutchinson Cancer Research Center and the Department of Medicine University of Washington School of Medicine Seattle Washington USA
| | - Jeffrey M. Caterino
- Department of Emergency Medicine The Ohio State University, Wexner Medical Center Columbus Ohio USA
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Choi HH, Zou S, Wu J, Wang H, Phan L, Li K, Zhang P, Chen D, Liu Q, Qin B, Nguyen TAT, Yeung SJ, Fang L, Lee M. EGF Relays Signals to COP1 and Facilitates FOXO4 Degradation to Promote Tumorigenesis. Adv Sci (Weinh) 2020; 7:2000681. [PMID: 33101846 PMCID: PMC7578864 DOI: 10.1002/advs.202000681] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/19/2020] [Indexed: 05/10/2023]
Abstract
Forkhead-Box Class O 4 (FOXO4) is involved in critical biological functions, but its response to EGF-PKB/Akt signal regulation is not well characterized. Here, it is reported that FOXO4 levels are downregulated in response to EGF treatment, with concurrent elevation of COP9 Signalosome subunit 6 (CSN6) and E3 ubiquitin ligase constitutive photomorphogenic 1 (COP1) levels. Mechanistic studies show that CSN6 binds and regulates FOXO4 stability through enhancing the E3 ligase activity of COP1, and that COP1 directly interacts with FOXO4 through a VP motif on FOXO4 and accelerates the ubiquitin-mediated degradation of FOXO4. Metabolomic studies demonstrate that CSN6 expression leads to serine and glycine production. It is shown that FOXO4 directly binds and suppresses the promoters of serine-glycine-one-carbon (SGOC) pathway genes, thereby diminishing SGOC metabolism. Evidence shows that CSN6 can regulate FOXO4-mediated SGOC gene expression. Thus, these data suggest a link of CSN6-FOXO4 axis and ser/gly metabolism. Further, it is shown that CSN6-COP1-FOXO4 axis is deregulated in cancer and that the protein expression levels of CSN6 and FOXO4 can serve as prognostic markers for cancers. The results illustrate a pathway regulation of FOXO4-mediated serine/glycine metabolism through the function of CSN6-COP1 axis. Insights into this pathway may be strategically designed for therapeutic intervention in cancers.
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Affiliation(s)
- Hyun Ho Choi
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Shaomin Zou
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Jian‐lin Wu
- State Key Laboratory of Quality Research in Chinese MedicineMacau Institute for Applied Research in Medicine and HealthMacau University of Science and TechnologyMacao999078China
| | - Huashe Wang
- Department of Colorectal SurgeryThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Liem Phan
- Department of Molecular and Cellular OncologyDivision of Basic Science ResearchThe University of Texas MD Anderson Cancer CenterHoustonTX77030USA
| | - Kai Li
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Peng Zhang
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Daici Chen
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Qingxin Liu
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Baifu Qin
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | | | - Sai‐Ching J. Yeung
- Department of Emergency MedicineDivision of Internal MedicineThe University of Texas MD Anderson Cancer CenterHoustonTX77030USA
| | - Lekun Fang
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Department of Colorectal SurgeryThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
| | - Mong‐Hong Lee
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor DiseaseThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
- Guangdong Research Institute of GastroenterologyThe Sixth Affiliated HospitalSun Yat‐sen UniversityGuangzhou510655China
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Thein KZ, Yeung SJ, Oo TH. Reply to M. Alexander et al. Asia Pac J Clin Oncol 2019; 15:185. [DOI: 10.1111/ajco.13098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 10/13/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Kyaw Zin Thein
- Department of Emergency MedicineThe University of Texas MD Anderson Cancer Center, Houston Texas USA
- Texas Tech University Health Sciences Center Lubbock Texas USA
| | - Sai‐Ching J Yeung
- Department of Emergency MedicineThe University of Texas MD Anderson Cancer Center, Houston Texas USA
| | - Thein Hlaing Oo
- Section of Thrombosis & Benign HematologyThe University of Texas MD Anderson Cancer Center Houston Texas USA
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Huyghe E, Kamar N, Wagner F, Yeung SJ, Capietto AH, El-Kahwaji L, Muscari F, Plante P, Rostaing L. Erectile dysfunction in liver transplant patients. Am J Transplant 2008; 8:2580-9. [PMID: 18853955 DOI: 10.1111/j.1600-6143.2008.02424.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The objectives of the study were to determine the frequency of erectile dysfunction (ED) after liver transplantation (LT) and discuss potential risk factors. Of 123 eligible LT men, 98 (79.7%) responded to a questionnaire about sexual function at a mean time posttransplant of 5.4 +/- 4.0 years (1.0-21). Erection was evaluated using the five-question international index for erectile function score, and sexual satisfaction by the patient-baseline treatment-satisfaction status (TSS) score. Questions also focused on patient perception of changes overtime. We found that after LT, the proportion of sexually inactive men decreased from 29% to 15% (p = 0.01), but the proportion of men with ED remained unchanged. The absence of sexual activity was associated with pretransplant sexual inactivity (p = 0.001), age (p = 0.008), cardiovascular disease (p = 0.03), use of diuretics (p = 0.04), anticoagulants (p = 0.001), statins (p = 0.01) and treatment for diabetes (p = 0.03). Cardiovascular disease (p = 0.05), posttransplantation diabetes (p = 0.04), alcohol abuse (p = 0.03), antidepressants (p = 0.05) and angiotensin II receptor blockers (p = 0.05) were associated with having ED after LT. Having a low TSS score was associated with a history of endocrine disease (p = 0.03), antidepressants (p = 0.04) and diuretics (p = 0.03). In conclusion, LT improves sexual activity, but ED is multifactorial and remains a long-term condition in the majority of patients.
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Affiliation(s)
- E Huyghe
- Department of Urology and Andrology, University Hospital, CHU Rangueil, Toulouse, France.
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Yeung SJ, McCutcheon IE, Schultz P, Gagel RF. Use of long-term intravenous phosphate infusion in the palliative treatment of tumor-induced osteomalacia. J Clin Endocrinol Metab 2000; 85:549-55. [PMID: 10690854 DOI: 10.1210/jcem.85.2.6368] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Tumor-induced osteomalacia is characterized by paraneoplastic defects in vitamin D metabolism, proximal renal tubular functions, and phosphate transport. The resulting hypophosphatemia can cause generalized pain and muscle weakness, which significantly affect the quality of life of the patients. Palliative treatment with calcium, vitamin D, and phosphate replacement is indicated for patients in whom the causative tumor cannot be completely resected. In this report we describe a case of tumor-induced osteomalacia in whom adequate oral doses of phosphate could not be used because of gastrointestinal side-effects. Long term (3-6 months) iv phosphate infusion delivered by ambulatory infusion pumps in combination with oral calcium and vitamin D was used successfully to decrease pain and increase muscle strength. Careful monitoring of serum calcium, phosphate, and creatinine levels and reliable microinfusion technology have allowed the long term use of iv phosphate infusion without serious morbidity. This patient received repeated (three times) phosphate infusions over 8 yr, resulting in laboratory and symptomatic improvement after each course. However, this patient did suffer two episodes of central venous catheter-related infection. Because of potentially serious complications, such as severe hypocalcemia, calcified right ventricular thrombi, and nephrocalcinosis, long term iv phosphate infusion should be reserved for patients who cannot tolerate adequate doses of oral phosphate and for whom the benefits outweigh the risks.
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Affiliation(s)
- S J Yeung
- Section of Endocrine Neoplasia and Hormonal Disorders, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
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Abstract
Newly synthesized apolipoprotein B (apoB) is degraded by a proteolytic process in the pre-Golgi compartment that can be inhibited by N-acetyl-L-leucinyl-L-leucinyl-L-norleucinal (ALLN) but not by several other protease inhibitors. We have tested the hypothesis that the ubiquitin-proteasome pathway is involved in the intracellular degradation of apoB in liver cells. We found that inhibitors of proteasomes blocked the degradation of apoB in cultured human hepatoma (HepG2) cells. Protein degradation by proteasomes is ATP-dependent, and ATP depletion by dinitrophenol and 2-deoxyglucose also inhibited apoB degradation in these cells. Furthermore, the intracellular human apoB isolated by immunoprecipitation was shown to react specifically with anti-ubiquitin antibody by immunoblotting. This result was corroborated by sequential immunoprecipitation of [35S]methionine-labeled proteins by anti-human apoB and anti-ubiquitin antisera. In contrast, secreted apoB was not ubiquitinated. The amount of intracellular ubiquitinated apoB was increased by the proteasome inhibitors, ALLN and carbobenzoxyl-leucinyl-leucinyl-norvalinal-H (MG115). Our findings suggest that the ubiquitin-proteasome pathway is one mechanism for the intracellular degradation of apoB.
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Affiliation(s)
- S J Yeung
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
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Bem WT, Yeung SJ, Belcheva M, Barg J, Coscia CJ. Age-dependent changes in the subcellular distribution of rat brain mu-opioid receptors and GTP binding regulatory proteins. J Neurochem 1991; 57:1470-7. [PMID: 1655974 DOI: 10.1111/j.1471-4159.1991.tb06340.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The relative subcellular distributions of mu-opioid receptors and guanine nucleotide binding regulatory proteins (G proteins) in 1-day-old (P1) and adult rat forebrain were compared. Light membranes (LMs) were resolved from heavy membranes (HM) by sucrose density gradient centrifugation. Marker enzyme analyses indicated that LMs contained most of the endoplasmic reticulum and Golgi complexes, whereas HMs were enriched in plasma membranes. Binding distribution and properties of mu-opioid sites were assessed using [3H] [D-Ala2,Me-Phe4,Gly-ol5]enkephalin. P1 LMs possessed 43% of the total mu-opioid binding detected compared to 16% in the adult. Although NaCl inhibited mu binding in LMs to a greater extent than in HMs, age-dependent differences were not observed. P1 LM mu binding possessed greater sensitivity to 5'-guanylylimidodiphosphate than their adult counterpart. Moreover, P1 LMs contained more Go alpha protein than P1 HMs or adult LMs, as demonstrated by immunoblotting with antisera against Go alpha after one- or two-dimensional gel electrophoresis. These results suggest that P1 LMs contain a greater proportion of newly synthesized intracellular mu sites than adult LMs.
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Affiliation(s)
- W T Bem
- Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University, Missouri
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Abstract
The effect of inhibitors of protein synthesis on the phase shifting action of light was investigated. Anisomycin and cycloheximide appeared to block advance phase shifts produced by light. This result suggested that light might phase shift by changing the synthesis of some proteins. Examining proteins separated by two-dimensional gel electrophoresis, we found that incorporation of amino acids into 11 proteins was changed during a 6-h light pulse. Nine of these 11 proteins were affected by light in a phase-dependent manner. Elevated extracellular potassium and 8-bromo-guanosine 3',5'-cyclic monophosphate (cGMP), two treatments that mimic effects of light on the rhythm, also changed amino acid incorporation into a number of proteins. All of the five proteins affected by 8-bromo-cGMP were also affected in the same manner by light. Three proteins were affected similarly by elevated potassium, light, and 8-bromo-cGMP. Exposure of eyes to label at different times after light treatment showed that the effects of light on some proteins were long lasting. In addition, some proteins were not affected during light but were affected only several hours after light. Some of the eye proteins affected by light were also altered by serotonin (5-HT), another phase-shifting agent. The proteins affected by light, elevated potassium, 8-bromo-cGMP, and 5-HT are candidates for components of the circadian system either as an element of the entrainment pathway or the oscillator mechanism.
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Affiliation(s)
- U Raju
- Department of Biochemical and Biophysical Sciences, University of Houston, Texas 77204-5500
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Abstract
Our previous results indicated that protein synthesis was necessary for serotonin (5-hydroxytryptamine, 5-HT) to regulate the phase of the biological clock in the Aplysia eye. Also, we showed that 5-HT appeared to increase the synthesis of a 34-kDa protein with an isoelectric point of 7.2. Subsequent studies were carried out to quantitate the effect of 5-HT on the 34-kDa protein and to examine whether the 34-kDa protein was involved in the circadian timing system. The regional specificity of the effect of 5-HT on the 34-kDa protein was investigated. The proximal portion of the eye appeared to synthesize much more of the 34-kDa protein than the distal portion. Also, 5-HT had a much larger effect on the synthesis of the 34-kDa protein in the proximal portion than in the distal portion. The proximal location of synthesis and the 5-HT effect on the synthesis of the 34-kDa protein correlate with the proximal location of cells and processes that are necessary for the expression of the circadian rhythm. The relationship between the effect of 5-HT on the circadian rhythm and the effect of 5-HT on the 34-kDa protein was also examined. As 5-HT causes phase shifts in the rhythm by activating adenylate cyclase to increase cAMP, forskolin and 8-benzylthioadenosine 3',5'-cyclic monophosphate mimicked the effect of 5-HT on the 34-kDa protein. We also found that 5-HT significantly increased the synthesis of the 34-kDa protein at phases when 5-HT delays or advances the phase of the rhythm but did not increase the synthesis of the 34-kDa protein at a phase when 5-HT did not phase shift. This phase-dependent effect of 5-HT on the 34-kDa protein qualitatively accounts for the phase dependence of the effect of 5-HT on the circadian rhythm. These results, when considered together with our earlier data, suggest that the synthesis of the 34-kDa protein is directly involved in the phase shift produced by 5-HT. The 34-kDa protein is worthy of future investigation as a candidate for a component of the circadian oscillator.
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Abstract
Serotonin (5-HT, 5-hydroxytryptamine) regulates the phase of a circadian pacemaker located within the eye of Aplysia. We are attempting to define the cellular and biochemical events involved in the regulatory pathway through which serotonin acts. Previously, we have shown that an activation of adenylate cyclase and an increase in cAMP are events in the 5-HT phase-shifting pathway. In this paper, we examine the role of protein synthesis in mediating the effect of 5-HT and cAMP on the phase of the circadian rhythm. Exposure of eyes to anisomycin, an inhibitor of protein synthesis, completely blocked the advance shift in phase produced by 5-HT. Although anisomycin by itself can produce phase shifts, it did not affect the rhythm at the phases where the blocking experiments were performed. The specificity of action of anisomycin was investigated in two ways. First, deacetylanisomycin, an analogue of anisomycin that is inactive in inhibiting protein synthesis, did not affect the shift in phase produced by 5-HT. Second, anisomycin did not inhibit two other effects of 5-HT on the eye that also appear to be mediated by cAMP: an inhibition of spontaneous optic nerve activity and an increase in the photosensitivity of the eye. The step in the 5-HT phase-shifting pathway that is sensitive to anisomycin appears to occur after the cAMP step because anisomycin also inhibits the ability of 8-benzylthio-cAMP to shift the phase of the rhythm. We have also examined whether 5-HT directly regulates the synthesis of any proteins in the eye. Using two-dimensional gel electrophoresis, we have found that 5-HT appears to increase the synthesis of a protein with an apparent molecular weight of 67,000. Our results indicate that protein synthesis is necessary for 5-HT to shift the phase of the rhythm and that 5-HT appears to regulate the expression of at least one protein in the eye.
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