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Lee J, Yun S, Kim Y, Chen T, Kellis M, Park C. Single-cell RNA sequencing data imputation using bi-level feature propagation. Brief Bioinform 2024; 25:bbae209. [PMID: 38706317 PMCID: PMC11070731 DOI: 10.1093/bib/bbae209] [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: 12/23/2023] [Revised: 04/08/2024] [Accepted: 04/19/2024] [Indexed: 05/07/2024] Open
Abstract
Single-cell RNA sequencing (scRNA-seq) enables the exploration of cellular heterogeneity by analyzing gene expression profiles in complex tissues. However, scRNA-seq data often suffer from technical noise, dropout events and sparsity, hindering downstream analyses. Although existing works attempt to mitigate these issues by utilizing graph structures for data denoising, they involve the risk of propagating noise and fall short of fully leveraging the inherent data relationships, relying mainly on one of cell-cell or gene-gene associations and graphs constructed by initial noisy data. To this end, this study presents single-cell bilevel feature propagation (scBFP), two-step graph-based feature propagation method. It initially imputes zero values using non-zero values, ensuring that the imputation process does not affect the non-zero values due to dropout. Subsequently, it denoises the entire dataset by leveraging gene-gene and cell-cell relationships in the respective steps. Extensive experimental results on scRNA-seq data demonstrate the effectiveness of scBFP in various downstream tasks, uncovering valuable biological insights.
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Affiliation(s)
- Junseok Lee
- Department of Industrial and Systems Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sukwon Yun
- Department of Computer Science, 201 S. Columbia St. CB 3175, UNC-Chapel Hill, Chapel Hill, NC 27599, United States
| | - Yeongmin Kim
- School of Computing, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Tianlong Chen
- Department of Computer Science, 201 S. Columbia St. CB 3175, UNC-Chapel Hill, Chapel Hill, NC 27599, United States
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, MA 02139, United States
- Broad Institute of MIT and Harvard, Merkin Building, 415 Main St., Cambridge, MA 02142, United States
| | - Manolis Kellis
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, MA 02139, United States
- Broad Institute of MIT and Harvard, Merkin Building, 415 Main St., Cambridge, MA 02142, United States
| | - Chanyoung Park
- Department of Industrial and Systems Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
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Zheng X, Wu M, Li S, Er L, Deng H, Guo S, Liu Z. Clinicopathological characteristics of rectal multiple neuroendocrine neoplasms and literature review. BMC Surg 2023; 23:147. [PMID: 37264328 DOI: 10.1186/s12893-023-02050-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/21/2023] [Indexed: 06/03/2023] Open
Abstract
BACKGROUND There are only a few epidemiological reports available for reference. The clinicopathological features are not clear, so there is no consensus on treating rectal multiple neuroendocrine neoplasms. This study aims to summarize the clinicopathological characteristics and preliminarily discuss the clinical diagnosis and treatment of rectal multiple neuroendocrine neoplasms. METHODS This study retrospectively analyzed rectal neuroendocrine neoplasm patients diagnosed and treated at the Fourth Hospital of Hebei Medical University from February 2007 to May 2021. The clinicopathological characteristics of rectal multiple neuroendocrine neoplasms were summarized and analyzed in combination with 14 studies on rectal multiple neuroendocrine neoplasms. RESULTS The incidence of RM-NENs accounted for 3.8% of all R-NENs in this study. The number of tumors varied to some extent, the size of tumors was basically no more than 10 mm, and there were more G1 grade tumors. In the analysis of 46 cases with known lymph node metastasis, the difference in lymph node metastasis rate between the number of tumors < 8 and ≥ 8 was statistically significant (p = 0.002). CONCLUSIONS The incidence of rectal multiple neuroendocrine neoplasms accounted for 3.8% of all rectal neuroendocrine neoplasms. For rectal multiple neuroendocrine neoplasms, the lymph node metastasis rate was higher when the number of tumors was ≥ 8. The influence of the number of tumors on lymph node metastasis should be considered in the selection of treatment.
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Affiliation(s)
- Xiuli Zheng
- Department of Endoscopy, Fourth Hospital of Hebei Medical University, No. 12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China
| | - Mingli Wu
- Department of Endoscopy, Fourth Hospital of Hebei Medical University, No. 12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China.
| | - Shengmian Li
- Department of Gastroenterology, Fourth Hospital of Hebei Medical University, No.12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China
| | - Limian Er
- Department of Endoscopy, Fourth Hospital of Hebei Medical University, No. 12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China
| | - Huiyan Deng
- Department of Pathology, Fourth Hospital of Hebei Medical University, No. 12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China
| | - Shuo Guo
- Department of Endoscopy, Fourth Hospital of Hebei Medical University, No. 12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China
| | - Zhihuan Liu
- Department of Endoscopy, Fourth Hospital of Hebei Medical University, No. 12 Jiankang Road, Chang'an District, Shijiazhuang, 050000, Hebei, China
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Vitale G, Dicitore A, Barrea L, Sbardella E, Razzore P, Campione S, Faggiano A, Colao A, Albertelli M, Altieri B, Bottiglieri F, De Cicco F, Di Molfetta S, Fanciulli G, Feola T, Ferone D, Ferraù F, Gallo M, Giannetta E, Grillo F, Grossrubatscher E, Guadagno E, Guarnotta V, Isidori AM, Lania A, Lenzi A, Calzo FL, Malandrino P, Messina E, Modica R, Muscogiuri G, Pes L, Pizza G, Pofi R, Puliani G, Rainone C, Rizza L, Rubino M, Ruggieri RM, Sesti F, Venneri MA, Zatelli MC. From microbiota toward gastro-enteropancreatic neuroendocrine neoplasms: Are we on the highway to hell? Rev Endocr Metab Disord 2021; 22:511-525. [PMID: 32935263 PMCID: PMC8346435 DOI: 10.1007/s11154-020-09589-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/04/2020] [Indexed: 02/06/2023]
Abstract
Gut microbiota is represented by different microorganisms that colonize the intestinal tract, mostly the large intestine, such as bacteria, fungi, archaea and viruses. The gut microbial balance has a key role in several functions. It modulates the host's metabolism, maintains the gut barrier integrity, participates in the xenobiotics and drug metabolism, and acts as protection against gastro-intestinal pathogens through the host's immune system modulation. The impaired gut microbiota, called dysbiosis, may be the result of an imbalance in this equilibrium and is linked with different diseases, including cancer. While most of the studies have focused on the association between microbiota and gastrointestinal adenocarcinomas, very little is known about gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs). In this review, we provide an overview concerning the complex interplay between gut microbiota and GEP NENs, focusing on the potential role in tumorigenesis and progression in these tumors.
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Affiliation(s)
- Giovanni Vitale
- Istituto Auxologico Italiano IRCCS, Laboratory of Geriatric and Oncologic Neuroendocrinology Research, Cusano Milanino, MI, Italy.
- Department of Clinical Sciences and Community Health (DISCCO), University of Milan, Milan, Italy.
| | - Alessandra Dicitore
- Department of Clinical Sciences and Community Health (DISCCO), University of Milan, Milan, Italy
| | - Luigi Barrea
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Emilia Sbardella
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Paola Razzore
- Endocrinology Unit, A.O. Ordine Mauriziano, Turin, Italy
| | | | | | - Annamaria Colao
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
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4
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Liu JF, Chen PC, Chang TM, Hou CH. Monocyte Chemoattractant Protein-1 promotes cancer cell migration via c-Raf/MAPK/AP-1 pathway and MMP-9 production in osteosarcoma. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2020; 39:254. [PMID: 33228783 PMCID: PMC7684958 DOI: 10.1186/s13046-020-01756-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/30/2020] [Indexed: 01/07/2023]
Abstract
Background Osteosarcoma is generally reported among younger individuals and has a very poor prognosis, particularly for the development of metastasis. However, more effective metastatic biomarkers and therapeutic methods are absent. Monocyte chemoattractant protein-1 (MCP-1) is involved in cancer progression and inflammatory recruitment. Although previous studies have reported higher serum MCP-1 levels in patients with osteosarcoma, the role of MCP-1 in osteosarcoma progression remains to be addressed. Methods The osteosarcoma cell migratory ability was assessed by transwell migration assay. The MCP-1 and MMP-9 expression levels were analyzed by Western blot and qPCR. The signal activation was conducted by Western blot. The in vivo mouse experiment and tumor tissue array were performed to confirm our findings in vitro. Results The present study demonstrates that MCP-1 regulates cell mobility through matrix metalloproteinase (MMP)-9 expression in osteosarcoma cells. Moreover, MCP-1 promotes MMP-9 expression, cell migration, and cell invasion by mediating CCR2, c-Raf, MAPK, and AP-1 signal transduction. Using MCP-1 knockdown stable cell lines, we found that MCP-1 knockdown reduces MMP-9 expression and cell mobility. Finally, we found high MCP-1 expression levels in osteosarcoma specimens. Conclusions Our results provide prognostic value of MCP-1 in osteosarcoma by promoting MMP-9 expression. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-020-01756-y.
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Affiliation(s)
- Ju-Fang Liu
- School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Po-Chun Chen
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, 40447, Taiwan.,Translational medicine center, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei City, 11101, Taiwan.,Department of Biotechnology, College of Medical and Health Science, Asia University, Taichung, 41354, Taiwan
| | - Tsung-Ming Chang
- School of Medicine, Institute of Physiology, National Yang-Ming University, Taipei City, 11221, Taiwan
| | - Chun-Han Hou
- Department of Orthopedic Surgery, National Taiwan University Hospital, 100, NO. 1, Jen-Ai Road, Taipei City, 11102, Taiwan, ROC.
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5
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Xie R, Fu KI, Chen SM, Tuo BG, Wu HC. Neurofibromatosis type 1-associated multiple rectal neuroendocrine tumors: A case report and review of the literature. World J Gastroenterol 2018; 24:3806-3812. [PMID: 30197486 PMCID: PMC6127664 DOI: 10.3748/wjg.v24.i33.3806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/12/2018] [Accepted: 07/21/2018] [Indexed: 02/06/2023] Open
Abstract
Neurofibromatosis type 1 (NF-1) is commonly associated with benign or malignant tumors in both the central and peripheral nervous systems. However, rare cases of NF-1-associated multiple rectal neuroendocrine tumors have been reported. This report describes a case of a 39 year old female with NF-1 and intermittent hematochezia as a primary symptom. Physical examination showed multiple subcutaneous nodules and café au lait spots with obvious scoliosis of the back. Imaging examinations and colonoscopy found malformation of the left external iliac vein and multiple gray-yellow nodules with varying sizes and shapes in the rectal submucosal layer. Histological and immunohistochemical results suggested multiple rectal neuroendocrine tumors, a rare disease with few appreciable symptoms and a particularly poor prognosis. The patient with NF-1 presented here had not only multiple rectal neuroendocrine neoplasms but also vascular malformations, scoliosis and other multiple system lesions. This case therefore contributes to improving clinical understanding, diagnosis and treatment of related complications for patients with NF-1 who present with associated medical conditions.
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Affiliation(s)
- Rui Xie
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Kuang-I Fu
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563003, Guizhou Province, China
- Department of Endoscopy, Kanma Memorial Hospital, Tokyo 3250046, Japan
| | - Shao-Min Chen
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Bi-Guang Tuo
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Hui-Chao Wu
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563003, Guizhou Province, China
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Aristizabal Prada ET, Auernhammer CJ. Targeted therapy of gastroenteropancreatic neuroendocrine tumours: preclinical strategies and future targets. Endocr Connect 2018; 7:R1-R25. [PMID: 29146887 PMCID: PMC5754510 DOI: 10.1530/ec-17-0286] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/16/2017] [Indexed: 12/12/2022]
Abstract
Molecular targeted therapy of advanced neuroendocrine tumours (NETs) of the gastroenteropancreatic (GEP) system currently encompasses approved therapy with the mammalian target of rapamycin (mTOR) inhibitor everolimus and the multi-tyrosinkinase inhibitor sunitinib. However, clinical efficacy of these treatment strategies is limited by low objective response rates and limited progression-free survival due to tumour resistance. Further novel strategies for molecular targeted therapy of NETs of the GEP system are needed. This paper reviews preclinical research models and signalling pathways in NETs of the GEP system. Preclinical and early clinical data on putative novel targets for molecular targeted therapy of NETs of the GEP system are discussed, including PI3K, Akt, mTORC1/mTORC2, GSK3, c-Met, Ras-Raf-MEK-ERK, embryogenic pathways (Hedgehog, Notch, Wnt/beta-catenin, TGF-beta signalling and SMAD proteins), tumour suppressors and cell cycle regulators (p53, cyclin-dependent kinases (CDKs) CDK4/6, CDK inhibitor p27, retinoblastoma protein (Rb)), heat shock protein HSP90, Aurora kinase, Src kinase family, focal adhesion kinase and epigenetic modulation by histone deacetylase inhibitors.
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Affiliation(s)
- E T Aristizabal Prada
- Department of Internal Medicine IVCampus Grosshadern, University-Hospital, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - C J Auernhammer
- Department of Internal Medicine IVCampus Grosshadern, University-Hospital, Ludwig-Maximilians-University of Munich, Munich, Germany
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Wang M, Xia X, Chu W, Xia L, Meng T, Liu L, Liu Y. Roles of miR-186 and PTTG1 in colorectal neuroendocrine tumors. Int J Clin Exp Med 2015; 8:22149-22157. [PMID: 26885189 PMCID: PMC4729975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/28/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVES This work aims to investigate the expression of miRNA-186 in patients with colorectal cancer tissues, blood and feces and its roles in regulating the infiltration and invasion in colorectal cancer. METHODS Totally 39 patients with surgical resection were included from August 2012 to February 2015 in Jilin Province People's Hospital as the Colorectal Neuroendocrine tumor (CNET). Peripheral blood, stool, and resected tumor tissues with adjacent normal of each patient was collected. In the same period, the blood and stool from 25 patients with hemorrhoids or other non-neoplastic diseases were collected and these samples used as clinical control group. MiR-186 expression and PTTG1 (pituitary tumor-transforming 1) expression were detected by quantitative Real-Time PCR (qRT-PCR). The PTTG1 protein expression in tumor samples were detected by Western Blot, while its expression in blood and stool were detected by Elisa. RESULTS Compared with the control group, the expression of PTTG1 mRNA and protein was significantly up-regulated in tumor samples, blood, and stool of patients with CNET, while the expression of miR-186 was down-regulated (P < 0.05). CONCLUSION PTTG1 expression was significantly up-regulated in patients with CNET, which was induced by the down-regulated miR-186. MiR-186 may participate in the regulation of infiltration and invasion in CNET patients through targeting PTTG1 expression.
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Affiliation(s)
- Maonan Wang
- Department of Anorectal Surgery, Jilin Province People’s HospitalChangchun 130021, Jilin, China
| | - Xin Xia
- Department of Anesthesiology, Jilin Province People’s HospitalChangchun 130021, Jilin, China
| | - Wenxiang Chu
- Department of Anorectal Surgery, Jilin Province People’s HospitalChangchun 130021, Jilin, China
| | - Liyan Xia
- Department of Anorectal Surgery, Jilin Province People’s HospitalChangchun 130021, Jilin, China
| | - Tao Meng
- Department of Anorectal Surgery, Jilin Province People’s HospitalChangchun 130021, Jilin, China
| | - Lintao Liu
- Department of Anorectal Surgery, Jilin Province People’s HospitalChangchun 130021, Jilin, China
| | - Yushi Liu
- Department of Anorectal Surgery, Jilin Province People’s HospitalChangchun 130021, Jilin, China
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Fazio N, Abdel-Rahman O, Spada F, Galdy S, De Dosso S, Capdevila J, Scarpa A. RAF signaling in neuroendocrine neoplasms: from bench to bedside. Cancer Treat Rev 2014; 40:974-9. [PMID: 24998490 DOI: 10.1016/j.ctrv.2014.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 12/23/2022]
Abstract
Neuroendocrine neoplasms are a low-incidence and heterogeneous group of malignancies. In the advanced stage, several therapeutic options can be discussed, including molecular-targeted agents, but biological predicting factors are lacking. A number of molecular targets have been studied over the last decade leading to several phase II studies; however, very few agents progressed to phase III clinical trials. The RAF family of proteins belongs to the mitogen-activated protein kinase (MAPK) pathway, that has a role in several types of cancers, particularly related to BRAF mutations. Indeed BRAF inhibitors have been reported as being effective, mainly in melanoma. However, in neuroendocrine neoplasms BRAF mutations are extremely rare and RAF-1 activation has been reported to inhibit tumor growth in a pre-clinical setting. Therefore, in this field, RAF-1 activators rather than BRAF inhibitors should be clinically investigated. This article reviews the basic science as well as clinical data of RAF signaling in advanced neuroendocrine neoplasms with special emphasis on the potential role of both RAF activators and inhibitors.
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Affiliation(s)
- Nicola Fazio
- Unit of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology, Milan, Italy.
| | - Omar Abdel-Rahman
- Clinical Oncology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Francesca Spada
- Unit of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology, Milan, Italy
| | - Salvatore Galdy
- Unit of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology, Milan, Italy
| | - Sara De Dosso
- Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
| | - Jaume Capdevila
- Medical Oncology Department, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Aldo Scarpa
- Department of Pathology and Diagnostics, ARC-NET Research Center, University of Verona, Italy
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Singh NS, Paul RK, Ramamoorthy A, Torjman MC, Moaddel R, Bernier M, Wainer IW. Nicotinic acetylcholine receptor antagonists alter the function and expression of serine racemase in PC-12 and 1321N1 cells. Cell Signal 2013; 25:2634-45. [PMID: 24012499 PMCID: PMC3846540 DOI: 10.1016/j.cellsig.2013.08.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/14/2013] [Accepted: 08/15/2013] [Indexed: 01/17/2023]
Abstract
Western blot analysis demonstrated that PC-12 cells express monomeric and dimeric forms of serine racemase (m-SR, d-SR) and that 1321N1 cells express m-SR. Quantitative RT-PCR and functional studies demonstrated that PC-12 cells express homomeric and heteromeric forms of nicotinic acetylcholine receptors (nAChR) while 1321N1 cells primarily express the α7-nAChR subtype. The effect of nAChR agonists and antagonists on SR activity and expression was examined by following concentration-dependent changes in intracellular d-Ser levels and SR protein expression. Incubation with (S)-nicotine increased d-Ser levels, which were attenuated by the α7-nAChR antagonist methyllycaconitine (MLA). Treatment of PC-12 cells with mecamylamine (MEC) produced a bimodal reduction of d-Ser reflecting MEC inhibition of homomeric and heteromeric nAChRs, while a unimodal curve was observed with 1321N1 cells, reflecting predominant expression of α7-nAChR. The nAChR subtype selectivity was probed using α7-nAChR selective inhibitors MLA and (R,S)-dehydronorketamine and α3β4-nAChR specific inhibitor AT-1001. The compounds reduced d-Ser in PC-12 cells, but only MLA and (R,S)-dehydronorketamine were effective in 1321N1 cells. Incubation of PC-12 and 1321N1 cells with (S)-nicotine, MEC and AT-1001 did not affect m-SR or d-SR expression, while MLA and (R,S)-dehydronorketamine increased m-SR expression but not SR mRNA levels. Treatment with cycloheximide indicated that increased m-SR was due to de novo protein synthesis associated with phospho-active forms of ERK1/2, MARCKS, Akt and rapamycin-sensitive mTOR. This effect was attenuated by treatment with the pharmacological inhibitors U0126, LY294002 and rapamycin, which selectively block the activation of ERK1/2, Akt and mTOR, respectively, and siRNAs directed against ERK1/2, Akt and mTOR. We propose that nAChR-associated changes in Ca(2+) flux affect SR activity, but not expression, and that MLA and (R,S)-dehydronorketamine bind to allosteric sites on the α7-nAChR and promote multiple signaling cascades that converge at mTOR to increase m-SR levels.
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Affiliation(s)
- Nagendra S. Singh
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Rajib K. Paul
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Anuradha Ramamoorthy
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Marc C. Torjman
- Biostatistical Group, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Ruin Moaddel
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Michel Bernier
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Irving W. Wainer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Abstract
Pancreatic neuroendocrine tumors (PNETs), also known as islet cell tumors, are mostly indolent neoplasms that probably arise from a network of endocrine cells that includes islet cells and pluripotent precursors in the pancreatic ductal epithelium. The incidence and prevalence of PNETs continue to rise in recent years because of more sensitive detection. The molecular pathogenesis, early detection, molecular predictors of tumor behavior, and targeted drug therapy of PNETs are not well understood and require additional basic and translational research. The rarity and indolent nature of these tumors, difficulty of access to appropriate patient tissue samples, and varying histopathology and secreted hormones pose particular challenges to PNET researchers. Animal models and cell lines are indispensable tools for investigating the pathogenesis, pathophysiology, mechanisms for tumor invasion and metastasis, and therapeutics of PNETs. This review summarizes currently available animal models and cell lines of PNETs, which have provided valuable insights into the pathogenesis and natural history of human PNETs. In the future, animal models and cell lines of PNETs should also be used to study early tumor detection and molecular predictors of tumor behavior and to test the responses to, and mechanisms for, novel targeted drug therapies.
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11
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Zhang J, Francois R, Iyer R, Seshadri M, Zajac-Kaye M, Hochwald SN. Current understanding of the molecular biology of pancreatic neuroendocrine tumors. J Natl Cancer Inst 2013; 105:1005-17. [PMID: 23840053 PMCID: PMC6281020 DOI: 10.1093/jnci/djt135] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/05/2013] [Accepted: 04/06/2013] [Indexed: 12/11/2022] Open
Abstract
Pancreatic neuroendocrine tumors (PanNETs) are complicated and often deadly neoplasms. A recent increased understanding of their molecular biology has contributed to expanded treatment options. DNA sequencing of samples derived from patients with PanNETs and rare genetic syndromes such as multiple endocrine neoplasia type 1 (MEN1) and Von Hippel-Lindau (VHL) syndrome reveals the involvement of MEN1, DAXX/ATRX, and the mammalian target of rapamycin (mTOR) pathways in PanNET tumorigenesis. Gene knock-out/knock-in studies indicate that inactivation of factors including MEN1 and abnormal PI3K/mTOR signaling uncouples endocrine cell cycle progression from the control of environmental cues such as glucose, leading to islet cell overgrowth. In addition, accumulating evidence suggests that further impairment of endothelial-endocrine cell interactions contributes to tumor invasion and metastasis. Recent phase III clinical trials have shown that therapeutic interventions, such as sunitinib and everolimus, targeting those signal transduction pathways improve disease-free survival rates. Yet, cure in the setting of advanced disease remains elusive. Further advances in our understanding of the molecular mechanisms of PanNETs and improved preclinical models will assist in developing personalized therapy utilizing novel drugs to provide prolonged control or even cure the disease.
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Affiliation(s)
- Jianliang Zhang
- Affiliations of authors:Department of Surgical Oncology (JZ, SNH), Department of Medical Oncology (RI), and Department of Pharmacology and Therapeutics (MS), Roswell Park Cancer Institute, Buffalo, NY; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL (RF, MZ-K)
| | - Rony Francois
- Affiliations of authors:Department of Surgical Oncology (JZ, SNH), Department of Medical Oncology (RI), and Department of Pharmacology and Therapeutics (MS), Roswell Park Cancer Institute, Buffalo, NY; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL (RF, MZ-K)
| | - Renuka Iyer
- Affiliations of authors:Department of Surgical Oncology (JZ, SNH), Department of Medical Oncology (RI), and Department of Pharmacology and Therapeutics (MS), Roswell Park Cancer Institute, Buffalo, NY; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL (RF, MZ-K)
| | - Mukund Seshadri
- Affiliations of authors:Department of Surgical Oncology (JZ, SNH), Department of Medical Oncology (RI), and Department of Pharmacology and Therapeutics (MS), Roswell Park Cancer Institute, Buffalo, NY; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL (RF, MZ-K)
| | - Maria Zajac-Kaye
- Affiliations of authors:Department of Surgical Oncology (JZ, SNH), Department of Medical Oncology (RI), and Department of Pharmacology and Therapeutics (MS), Roswell Park Cancer Institute, Buffalo, NY; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL (RF, MZ-K)
| | - Steven N. Hochwald
- Affiliations of authors:Department of Surgical Oncology (JZ, SNH), Department of Medical Oncology (RI), and Department of Pharmacology and Therapeutics (MS), Roswell Park Cancer Institute, Buffalo, NY; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL (RF, MZ-K)
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Abstract
The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. It divides the seminiferous epithelium into the basal and the apical (adluminal) compartments. Meiosis I and II, spermiogenesis, and spermiation all take place in a specialized microenvironment behind the BTB in the apical compartment, but spermatogonial renewal and differentiation and cell cycle progression up to the preleptotene spermatocyte stage take place outside of the BTB in the basal compartment of the epithelium. However, the BTB is not a static ultrastructure. Instead, it undergoes extensive restructuring during the seminiferous epithelial cycle of spermatogenesis at stage VIII to allow the transit of preleptotene spermatocytes at the BTB. Yet the immunological barrier conferred by the BTB cannot be compromised, even transiently, during the epithelial cycle to avoid the production of antibodies against meiotic and postmeiotic germ cells. Studies have demonstrated that some unlikely partners, namely adhesion protein complexes (e.g., occludin-ZO-1, N-cadherin-β-catenin, claudin-5-ZO-1), steroids (e.g., testosterone, estradiol-17β), nonreceptor protein kinases (e.g., focal adhesion kinase, c-Src, c-Yes), polarity proteins (e.g., PAR6, Cdc42, 14-3-3), endocytic vesicle proteins (e.g., clathrin, caveolin, dynamin 2), and actin regulatory proteins (e.g., Eps8, Arp2/3 complex), are working together, apparently under the overall influence of cytokines (e.g., transforming growth factor-β3, tumor necrosis factor-α, interleukin-1α). In short, a "new" BTB is created behind spermatocytes in transit while the "old" BTB above transiting cells undergoes timely degeneration, so that the immunological barrier can be maintained while spermatocytes are traversing the BTB. We also discuss recent findings regarding the molecular mechanisms by which environmental toxicants (e.g., cadmium, bisphenol A) induce testicular injury via their initial actions at the BTB to elicit subsequent damage to germ-cell adhesion, thereby leading to germ-cell loss, reduced sperm count, and male infertility or subfertility. Moreover, we also critically evaluate findings in the field regarding studies on drug transporters in the testis and discuss how these influx and efflux pumps regulate the entry of potential nonhormonal male contraceptives to the apical compartment to exert their effects. Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men.
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Affiliation(s)
- C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA.
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