1
|
Kirk AM, Crawford JC, Chou CH, Guy C, Pandey K, Kozlik T, Shah RK, Chung S, Nguyen P, Zhang X, Wang J, Bell M, Mettelman RC, Allen EK, Pogorelyy MV, Kim H, Minervina AA, Awad W, Bajracharya R, White T, Long D, Gordon B, Morrison M, Glazer ES, Murphy AJ, Jiang Y, Fitzpatrick EA, Yarchoan M, Sethupathy P, Croft NP, Purcell AW, Federico SM, Stewart E, Gottschalk S, Zamora AE, DeRenzo C, Strome SE, Thomas PG. DNAJB1-PRKACA fusion neoantigens elicit rare endogenous T cell responses that potentiate cell therapy for fibrolamellar carcinoma. Cell Rep Med 2024; 5:101469. [PMID: 38508137 PMCID: PMC10983114 DOI: 10.1016/j.xcrm.2024.101469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/29/2023] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
Fibrolamellar carcinoma (FLC) is a liver tumor with a high mortality burden and few treatment options. A promising therapeutic vulnerability in FLC is its driver mutation, a conserved DNAJB1-PRKACA gene fusion that could be an ideal target neoantigen for immunotherapy. In this study, we aim to define endogenous CD8 T cell responses to this fusion in FLC patients and evaluate fusion-specific T cell receptors (TCRs) for use in cellular immunotherapies. We observe that fusion-specific CD8 T cells are rare and that FLC patient TCR repertoires lack large clusters of related TCR sequences characteristic of potent antigen-specific responses, potentially explaining why endogenous immune responses are insufficient to clear FLC tumors. Nevertheless, we define two functional fusion-specific TCRs, one of which has strong anti-tumor activity in vivo. Together, our results provide insights into the fragmented nature of neoantigen-specific repertoires in humans and indicate routes for clinical development of successful immunotherapies for FLC.
Collapse
Affiliation(s)
- Allison M Kirk
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jeremy Chase Crawford
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ching-Heng Chou
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Cliff Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kirti Pandey
- Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Tanya Kozlik
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ravi K Shah
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Shanzou Chung
- Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Phuong Nguyen
- Department of Bone Marrow Transplantation and Cellular Therapy, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xiaoyu Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jin Wang
- Department of Microbiology, Immunology, and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Matthew Bell
- Department of Bone Marrow Transplantation and Cellular Therapy, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Robert C Mettelman
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - E Kaitlynn Allen
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Mikhail V Pogorelyy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hyunjin Kim
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Anastasia A Minervina
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Walid Awad
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Resha Bajracharya
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Bone Marrow Transplantation and Cellular Therapy, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Toni White
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Donald Long
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14850, USA
| | - Brittney Gordon
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michelle Morrison
- Center for Cancer Research, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Evan S Glazer
- Center for Cancer Research, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163, USA; Department of Surgery, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Andrew J Murphy
- Department of Surgery, The University of Tennessee Health Science Center, Memphis, TN 38163, USA; Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Yixing Jiang
- Department of Medical Oncology, Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Elizabeth A Fitzpatrick
- Department of Microbiology, Immunology, and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Mark Yarchoan
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Praveen Sethupathy
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14850, USA
| | - Nathan P Croft
- Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Anthony W Purcell
- Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Sara M Federico
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Elizabeth Stewart
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Stephen Gottschalk
- Department of Bone Marrow Transplantation and Cellular Therapy, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Anthony E Zamora
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Christopher DeRenzo
- Department of Bone Marrow Transplantation and Cellular Therapy, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Scott E Strome
- College of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Paul G Thomas
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| |
Collapse
|
2
|
Ma RK, Tsai PY, Farghli AR, Shumway A, Kanke M, Gordan JD, Gujral TS, Vakili K, Nukaya M, Noetzli L, Ronnekleiv-Kelly S, Broom W, Barrow J, Sethupathy P. DNAJB1-PRKACA fusion protein-regulated LINC00473 promotes tumor growth and alters mitochondrial fitness in fibrolamellar carcinoma. PLoS Genet 2024; 20:e1011216. [PMID: 38512964 PMCID: PMC11020935 DOI: 10.1371/journal.pgen.1011216] [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: 09/14/2023] [Revised: 04/16/2024] [Accepted: 03/08/2024] [Indexed: 03/23/2024] Open
Abstract
Fibrolamellar carcinoma (FLC) is a rare liver cancer that disproportionately affects adolescents and young adults. Currently, no standard of care is available and there remains a dire need for new therapeutics. Most patients harbor the fusion oncogene DNAJB1-PRKACA (DP fusion), but clinical inhibitors are not yet developed and it is critical to identify downstream mediators of FLC pathogenesis. Here, we identify long noncoding RNA LINC00473 among the most highly upregulated genes in FLC tumors and determine that it is strongly suppressed by RNAi-mediated inhibition of the DP fusion in FLC tumor epithelial cells. We show by loss- and gain-of-function studies that LINC00473 suppresses apoptosis, increases the expression of FLC marker genes, and promotes FLC growth in cell-based and in vivo disease models. Mechanistically, LINC00473 plays an important role in promoting glycolysis and altering mitochondrial activity. Specifically, LINC00473 knockdown leads to increased spare respiratory capacity, which indicates mitochondrial fitness. Overall, we propose that LINC00473 could be a viable target for this devastating disease.
Collapse
Affiliation(s)
- Rosanna K. Ma
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Pei-Yin Tsai
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
| | - Alaa R. Farghli
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Alexandria Shumway
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Matt Kanke
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - John D. Gordan
- Division of Hematology/Oncology, Helen Diller Family Comprehensive Cancer Center, UCSF, San Francisco, California, United States of America
| | - Taranjit S. Gujral
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Khashayar Vakili
- Department of Surgery, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Manabu Nukaya
- Department of Surgery, Division of Surgical Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Leila Noetzli
- Alnylam Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Sean Ronnekleiv-Kelly
- Department of Surgery, Division of Surgical Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Wendy Broom
- Alnylam Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Joeva Barrow
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
| | - Praveen Sethupathy
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| |
Collapse
|
3
|
Lauer SM, Omar MH, Golkowski MG, Kenerson HL, Lee KS, Pascual BC, Lim HC, Forbush K, Smith FD, Gordan JD, Ong SE, Yeung RS, Scott JD. Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma. Cell Rep 2024; 43:113678. [PMID: 38236773 PMCID: PMC10964278 DOI: 10.1016/j.celrep.2024.113678] [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: 07/21/2023] [Revised: 11/23/2023] [Accepted: 01/02/2024] [Indexed: 01/30/2024] Open
Abstract
The DNAJ-PKAc fusion kinase is a defining feature of fibrolamellar carcinoma (FLC). FLC tumors are notoriously resistant to standard chemotherapies, with aberrant kinase activity assumed to be a contributing factor. By combining proximity proteomics, biochemical analyses, and live-cell photoactivation microscopy, we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates, including proteins involved in translation and the anti-apoptotic factor Bcl-2-associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Tissue samples from patients with FLC exhibit increased levels of BAG2 in primary and metastatic tumors. Furthermore, drug studies implicate the DNAJ-PKAc/Hsp70/BAG2 axis in potentiating chemotherapeutic resistance. We find that the Bcl-2 inhibitor navitoclax enhances sensitivity to etoposide-induced apoptosis in cells expressing DNAJ-PKAc. Thus, our work indicates BAG2 as a marker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.
Collapse
Affiliation(s)
- Sophia M Lauer
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Mitchell H Omar
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Martin G Golkowski
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Heidi L Kenerson
- Department of Surgery, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Bryan C Pascual
- Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Huat C Lim
- Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Katherine Forbush
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - F Donelson Smith
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - John D Gordan
- Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Raymond S Yeung
- Department of Surgery, University of Washington Medical Center, Seattle, WA 98195, USA
| | - John D Scott
- Department of Pharmacology, University of Washington Medical Center, Seattle, WA 98195, USA.
| |
Collapse
|
4
|
Akins RB, Ostberg K, Cherlin T, Tsiouplis NJ, Loher P, Rigoutsos I. The Typical tRNA Co-Expresses Multiple 5' tRNA Halves Whose Sequences and Abundances Depend on Isodecoder and Isoacceptor and Change with Tissue Type, Cell Type, and Disease. Noncoding RNA 2023; 9:69. [PMID: 37987365 PMCID: PMC10660753 DOI: 10.3390/ncrna9060069] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/02/2023] [Accepted: 10/12/2023] [Indexed: 11/22/2023] Open
Abstract
Transfer RNA-derived fragments (tRFs) are noncoding RNAs that arise from either mature transfer RNAs (tRNAs) or their precursors. One important category of tRFs comprises the tRNA halves, which are generated through cleavage at the anticodon. A given tRNA typically gives rise to several co-expressed 5'-tRNA halves (5'-tRHs) that differ in the location of their 3' ends. These 5'-tRHs, even though distinct, have traditionally been treated as indistinguishable from one another due to their near-identical sequences and lengths. We focused on co-expressed 5'-tRHs that arise from the same tRNA and systematically examined their exact sequences and abundances across 10 different human tissues. To this end, we manually curated and analyzed several hundred human RNA-seq datasets from NCBI's Sequence Run Archive (SRA). We grouped datasets from the same tissue into their own collection and examined each group separately. We found that a given tRNA produces different groups of co-expressed 5'-tRHs in different tissues, different cell lines, and different diseases. Importantly, the co-expressed 5'-tRHs differ in their sequences, absolute abundances, and relative abundances, even among tRNAs with near-identical sequences from the same isodecoder or isoacceptor group. The findings suggest that co-expressed 5'-tRHs that are produced from the same tRNA or closely related tRNAs have distinct, context-dependent roles. Moreover, our analyses show that cell lines modeling the same tissue type and disease may not be interchangeable when it comes to experimenting with tRFs.
Collapse
Affiliation(s)
| | | | | | | | | | - Isidore Rigoutsos
- Computational Medical Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| |
Collapse
|
5
|
Fibrolamellar Hepatocellular Carcinoma: Comprehensive Review of Diagnosis, Imaging, and Management. J Am Coll Surg 2023; 236:399-410. [PMID: 36648268 DOI: 10.1097/xcs.0000000000000476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Fibrolamellar hepatocellular carcinoma (FLC) is a rare malignancy that primarily affects patients in late adolescence and young adulthood. FLC tumors are characterized by their unique histologic features and a recently discovered genomic alteration, a chimeric fusion protein found in nearly all tumors. This review article provides the latest advancements in diagnosing, imaging, and managing FLC. STUDY DESIGN A comprehensive systematic review was performed using MEDLINE/PubMed and Web of Science databases, with the end of search date being July 1, 2022, regarding FLC diagnosis, imaging, and management. RESULTS Surgical resection remains the mainstay of therapy offering a chance for cure; however, given the incidence of metastatic disease at diagnosis and high rates of distant relapse, systemic therapies remain a crucial component of disease control. Unfortunately, few systemic therapies have demonstrated proven benefits. Consequently, recent efforts have galvanized around single-institute or small consortia-based studies specifically focused on enrolling patients with FLC or using agents with a biologic rationale. CONCLUSIONS FLC has unique demographic, radiologic, and pathologic features. The rarity of these tumors, coupled with the only recent acknowledgment of the genomic abnormality, has likely led to disease underrecognition and deprioritization of collaborative efforts to establish an evidence-based standard of care. Despite R0 resection, most patients experience recurrence. However, surgical resection is feasible for many recurrences and is associated with good survival. The role of chemotherapy is evolving, and further research is required to define its role in managing this disease.
Collapse
|
6
|
Francisco AB, Li J, Farghli AR, Kanke M, Shui B, Munn PR, Grenier JK, Soloway PD, Wang Z, Reid LM, Liu J, Sethupathy P. Chemical, Molecular, and Single-nucleus Analysis Reveal Chondroitin Sulfate Proteoglycan Aberrancy in Fibrolamellar Carcinoma. CANCER RESEARCH COMMUNICATIONS 2022; 2:663-678. [PMID: 36923282 PMCID: PMC10010304 DOI: 10.1158/2767-9764.crc-21-0177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/21/2022] [Accepted: 06/22/2022] [Indexed: 11/16/2022]
Abstract
Fibrolamellar carcinoma (FLC) is an aggressive liver cancer with no effective therapeutic options. The extracellular environment of FLC tumors is poorly characterized and may contribute to cancer growth and/or metastasis. To bridge this knowledge gap, we assessed pathways relevant to proteoglycans, a major component of the extracellular matrix. We first analyzed gene expression data from FLC and nonmalignant liver tissue (n = 27) to identify changes in glycosaminoglycan (GAG) biosynthesis pathways and found that genes associated with production of chondroitin sulfate, but not other GAGs, are significantly increased by 8-fold. We then implemented a novel LC/MS-MS based method to quantify the abundance of different types of GAGs in patient tumors (n = 16) and found that chondroitin sulfate is significantly more abundant in FLC tumors by 6-fold. Upon further analysis of GAG-associated proteins, we found that versican (VCAN) expression is significantly upregulated at the mRNA and protein levels, the latter of which was validated by IHC. Finally, we performed single-cell assay for transposase-accessible chromatin sequencing on FLC tumors (n = 3), which revealed for the first time the different cell types in FLC tumors and also showed that VCAN is likely produced not only from FLC tumor epithelial cells but also activated stellate cells. Our results reveal a pathologic aberrancy in chondroitin (but not heparan) sulfate proteoglycans in FLC and highlight a potential role for activated stellate cells. Significance This study leverages a multi-disciplinary approach, including state-of-the-art chemical analyses and cutting-edge single-cell genomic technologies, to identify for the first time a marked chondroitin sulfate aberrancy in FLC that could open novel therapeutic avenues in the future.
Collapse
Affiliation(s)
- Adam B Francisco
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Jine Li
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina.,Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Alaa R Farghli
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Matt Kanke
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Bo Shui
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Paul R Munn
- Genomics Innovation Hub, Biotechnology Resource Center, Cornell University, Ithaca, New York
| | - Jennifer K Grenier
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York.,Genomics Innovation Hub, Biotechnology Resource Center, Cornell University, Ithaca, New York
| | - Paul D Soloway
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Zhangjie Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, P.R. China
| | - Lola M Reid
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Jian Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina
| | - Praveen Sethupathy
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| |
Collapse
|
7
|
Bolger GB. The cAMP-signaling cancers: Clinically-divergent disorders with a common central pathway. Front Endocrinol (Lausanne) 2022; 13:1024423. [PMID: 36313756 PMCID: PMC9612118 DOI: 10.3389/fendo.2022.1024423] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 09/27/2022] [Indexed: 12/01/2022] Open
Abstract
The cAMP-signaling cancers, which are defined by functionally-significant somatic mutations in one or more elements of the cAMP signaling pathway, have an unexpectedly wide range of cell origins, clinical manifestations, and potential therapeutic options. Mutations in at least 9 cAMP signaling pathway genes (TSHR, GPR101, GNAS, PDE8B, PDE11A, PRKARA1, PRKACA, PRKACB, and CREB) have been identified as driver mutations in human cancer. Although all cAMP-signaling pathway cancers are driven by mutation(s) that impinge on a single signaling pathway, the ultimate tumor phenotype reflects interactions between five critical variables: (1) the precise gene(s) that undergo mutation in each specific tumor type; (2) the effects of specific allele(s) in any given gene; (3) mutations in modifier genes (mutational "context"); (4) the tissue-specific expression of various cAMP signaling pathway elements in the tumor stem cell; and (5) and the precise biochemical regulation of the pathway components in tumor cells. These varying oncogenic mechanisms reveal novel and important targets for drug discovery. There is considerable diversity in the "druggability" of cAMP-signaling components, with some elements (GPCRs, cAMP-specific phosphodiesterases and kinases) appearing to be prime drug candidates, while other elements (transcription factors, protein-protein interactions) are currently refractory to robust drug-development efforts. Further refinement of the precise driver mutations in individual tumors will be essential for directing priorities in drug discovery efforts that target these mutations.
Collapse
|