High FA2H and UGT8 transcript levels predict hydroxylated hexosylceramide accumulation in lung adenocarcinoma

Lung cancer causes more deaths than any other cancer. Sphingolipids encompass metabolically interconnected species whose balance has pivotal effects on proliferation, migration, and apoptosis. In this study, we paralleled quantification of sphingolipid species with quantitative (q)PCR analyses of metabolic enzymes in order to identify dysregulated routes of sphingolipid metabolism in different subtypes of lung cancers. Lung samples were submitted to histopathological reexamination in order to confirm cancer type/subtype, which included adenocarcinoma histological subtypes and squamous cell and neuroendocrine carcinomas. Compared with benign lesions and tumor-free parenchyma, all cancers featured decreased sphingosine-1-phosphate and SMs. qPCR analyses evidenced differential mechanisms leading to these alterations between cancer types, with neuroendocrine carcinomas upregulating SGPL1, but CERT1 being downregulated in adenocarcinomas and squamous cell carcinomas. 2-Hydroxyhexosylceramides (2-hydroxyHexCers) were specifically increased in adenocarcinomas. While UDP-glycosyltransferase 8 (UGT8) transcript levels were increased in all cancer subtypes, fatty acid 2-hydroxylase (FA2H) levels were higher in adenocarcinomas than in squamous and neuroendocrine carcinomas. As a whole, we report differing mechanisms through which all forms of lung cancer achieve low SM and lysosphingolipids. Our results also demonstrate that FA2H upregulation is required for the accumulation of 2-hydroxyHexCers in lung cancers featuring high levels of UGT8. Lung cancer causes more deaths than any other cancer. Sphingolipids encompass metabolically interconnected species whose balance has pivotal effects on proliferation, migration, and apoptosis. In this study, we paralleled quantification of sphingolipid species with quantitative (q)PCR analyses of metabolic enzymes in order to identify dysregulated routes of sphingolipid metabolism in different subtypes of lung cancers. Lung samples were submitted to histopathological reexamination in order to confirm cancer type/subtype, which included adenocarcinoma histological subtypes and squamous cell and neuroendocrine carcinomas. Compared with benign lesions and tumor-free parenchyma, all cancers featured decreased sphingosine-1-phosphate and SMs. qPCR analyses evidenced differential mechanisms leading to these alterations between cancer types, with neuroendocrine carcinomas upregulating SGPL1, but CERT1 being downregulated in adenocarcinomas and squamous cell carcinomas. 2-Hydroxyhexosylceramides (2-hydroxyHexCers) were specifically increased in adenocarcinomas. While UDP-glycosyltransferase 8 (UGT8) transcript levels were increased in all cancer subtypes, fatty acid 2-hydroxylase (FA2H) levels were higher in adenocarcinomas than in squamous and neuroendocrine carcinomas. As a whole, we report differing mechanisms through which all forms of lung cancer achieve low SM and lysosphingolipids. Our results also demonstrate that FA2H upregulation is required for the accumulation of 2-hydroxyHexCers in lung cancers featuring high levels of UGT8. Lung cancer is the leading cause of cancer-related deaths worldwide, with an estimated 1.8 million deaths per year (1Torre L.A. Siegel R.L. Jemal A. Lung cancer statistics.In Lung Cancer and Personalized Medicine: Current Knowledge and Therapies. A. Ahmad and S. Gadgeel, editors. Springer International Publishing, Cham, Switzerland2016: 1-19Crossref Scopus (1326) Google Scholar). The overall prognosis of lung cancer patients is poor, with an 18% survival rate after 5 years (1Torre L.A. Siegel R.L. Jemal A. Lung cancer statistics.In Lung Cancer and Personalized Medicine: Current Knowledge and Therapies. A. Ahmad and S. Gadgeel, editors. Springer International Publishing, Cham, Switzerland2016: 1-19Crossref Scopus (1326) Google Scholar). Given the clinical advantage of cancer type-specific therapies, it is required to enhance our understanding of differential mechanisms underlying lung cancers. Sphingolipid alterations are increasingly associated with oncogenesis (2Don A.S. Lim X.Y. 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Considering the dynamic metabolic links between these bioactive lipids, a more global pathway analysis should enhance our understanding of their involvement in different types of cancer and potentially lead to the identification of new targets, or combinations of targets, to interfere with lesion-specific mechanisms of oncogenesis. Histological types of lung cancer are associated with specific biological processes (16Li L. Wei Y. To C. Zhu C.Q. Tong J. Pham N.A. Taylor P. Ignatchenko V. Ignatchenko A. Zhang W. et al.Integrated omic analysis of lung cancer reveals metabolism proteome signatures with prognostic impact.Nat. Commun. 2014; 5: 5469Crossref PubMed Scopus (73) Google Scholar), which could be specifically targeted if better understood. In the last decade, the development of several targeted lung cancer therapies based on histological characteristics increased progression-free survival (17Chan B.A. Hughes B.G.M. Targeted therapy for non-small cell lung cancer: current standards and the promise of the future.Transl. Lung Cancer Res. 2015; 4: 36-54PubMed Google Scholar), but the need for identifying alterations with therapeutic potential for specific histological types of lung cancers remains. In this study, we compared sphingolipid species and the transcript levels of selected sphingolipid-metabolizing enzymes across adenocarcinoma and squamous and neuroendocrine lung cancers classified using the latest recommendations of the World Health Organization (18Travis W.D. Brambilla E. Nicholson A.G. Yatabe Y. Austin J.H. Beasley M.B. Chirieac L.R. Dacic S. Duhig E. Flieder D.B. et al.The 2015 World Health Organization classification of lung tumors: impact of genetic, clinical and radiologic advances since the 2004 classification.J. Thorac. Oncol. 2015; 10: 1243-1260Abstract Full Text Full Text PDF PubMed Scopus (2592) Google Scholar). We found SMs, sphingosine, sphinganine, and sphingosine-1-phosphate (S1P) to be decreased in all of the investigated types of lung cancer, while hexosylceramides (HexCers) and 2-hydroxyhexosylceramides (2-hydroxyHexCers) were specifically increased in adenocarcinomas. The patients included in this study were diagnosed with low stage lung cancers and underwent surgical resection between the years 2000 and 2016 at the Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ). The patients signed a consent form allowing the utilization of their tissues for research purposes. Samples were collected and using that Y. M. C. P. V. M. M. et of in human lung Res. PubMed Scopus Google Scholar). Samples were at the of the Health of the de of tumor and to were required for included of that sphingolipid levels (12Truman J-P. García-Barros M. Obeid L.M. Hannun Y.A. Evolving concepts in cancer therapy through targeting sphingolipid metabolism.Biochim. Biophys. Acta. 2014; 1841: 1174-1188Crossref PubMed Scopus (92) Google and sphingolipid or this we samples patients whose histological types were by a to the 2015 World Health Organization (18Travis W.D. Brambilla E. Nicholson A.G. Yatabe Y. Austin J.H. Beasley M.B. Chirieac L.R. Dacic S. Duhig E. Flieder D.B. et al.The 2015 World Health Organization classification of lung tumors: impact of genetic, clinical and radiologic advances since the 2004 classification.J. Thorac. Oncol. 2015; 10: 1243-1260Abstract Full Text Full Text PDF PubMed Scopus (2592) Google were classified and solid or or adenocarcinoma patients were also In and patients for benign lung were were to the recommendations A. J. R. M. L.M. et for the and of lung J. Med. 2017; PubMed Scopus Google Scholar). The study by the and by the of of high low different neuroendocrine patients different neuroendocrine patients per different neuroendocrine patients different neuroendocrine patients different adenocarcinoma low and neuroendocrine patients different adenocarcinoma low and neuroendocrine patients different neuroendocrine patients different neuroendocrine patients different neuroendocrine patients different neuroendocrine patients stage of the lung for different neuroendocrine patients different adenocarcinoma low and neuroendocrine patients in a new of the lung for samples L. D. D. B. A.S. and analysis of sphingolipids in J. 2011; PubMed Scopus Google Scholar). of lung in using of the for quantification and of to the of the for a of A of standards in to at the of the standards included sphingosine and SM and were were on a and using a A.S. quantification of metabolites in selected Chem. PubMed Scopus Google Scholar). were the species for The for SM the for all other sphingolipids containing a sphingosine and the for using and using a of samples were analysis to levels the of of lung samples with an and with an to quantitative (q)PCR were for using in a and to the of for across ceramide in a new ceramide and are using and a were using or were using with the could be to a analysis with the The of for for which analyses were using The with the after a on the analyses were using the and for characteristics of patients were different between cancer types, with the of and of patients with neuroendocrine a higher of the lung for in this As A. W.D. of classification of lung prognostic and for of based on analysis of stage I 2011; PubMed Scopus Google Scholar), adenocarcinomas and squamous cell carcinoma featured the high and overall clinical lesions featured lesions A. M. tumors of the 4: PubMed Scopus Google Scholar). The adenocarcinoma featured all adenocarcinoma types with a of the and As patients with while the of to between the cancer and featured 1 and 2 our to of patients whose clinical were with A. W.D. of classification of lung prognostic and for of based on analysis of stage I 2011; PubMed Scopus Google Scholar, A. M. tumors of the 4: PubMed Scopus Google Scholar, J.A. A. H. factors for survival of stage I cell lung cancer 2007; PubMed Scopus Google Scholar). Given the between a of cell and phospholipid in lung The of the of cell PubMed Scopus Google Scholar), lipids were to the in order to between samples with differing levels of lipid class were compared between were between lipid class of in with the of that with higher than between In with sphingolipid levels in lung E. M. T. S. S. R. J. de R. J. J. et cell lung cancer is by in phospholipid J. Cancer. 2015; PubMed Scopus Google Scholar), we found that the species SM were by ceramides 1 and 1 In our lung tumor survival with the of sphingolipid We found of sphingolipid between benign lung samples and cancer patients 1 The of ceramides between tumor and tumor-free tissues for squamous cell ceramides were decreased to their In tumor levels of sphingosine and SMs compared with tumor-free of the cancer Sphingolipid that cancer types were also to tumor-free 2-hydroxyHexCers were increased in adenocarcinoma tumors and this in and adenocarcinomas with and of patients more 2-hydroxyHexCers in their tumor than in in any of the other cancer types lesions the levels of sphingosine, and and with levels different the other cancer sphingolipid levels are in tumors compared with and specific alterations were in adenocarcinomas and squamous cell and neuroendocrine lung cancers. to of adenocarcinomas in patients have and lung cancers in this have clinical and biological R. Zhang W. R. P. C.E. et adenocarcinoma of and differential of and different levels of PubMed Scopus Google that different our results that have a impact on lipid levels in lung and benign patients levels of all lipid The lipid alterations in tumor tissues of adenocarcinoma patients were also in tumor tissues adenocarcinoma patients including the in have an impact at the sphingolipid in adenocarcinoma Sphingolipids to a family of lipids by specific enzymes (12Truman J-P. García-Barros M. Obeid L.M. Hannun Y.A. Evolving concepts in cancer therapy through targeting sphingolipid metabolism.Biochim. Biophys. Acta. 2014; 1841: 1174-1188Crossref PubMed Scopus (92) Google Scholar). We of sphingolipid-metabolizing enzymes and to the lipid levels of for the were different between benign and adenocarcinoma UDP-glycosyltransferase 8 which the increased in all cancer types to acid 2-hydroxylase (FA2H) higher in types of adenocarcinomas compared with the other cancer types Compared with benign lesions and the of the investigated featured decreased transcript including ceramide 1 which decreased in squamous cell carcinoma and adenocarcinomas We also with decreased specifically in the cancer types, squamous carcinomas and including SM sphingosine kinase 2 and SM carcinomas featured the with in 1 and and a in to be between transcript levels and the of sphingolipids in the several cancer types, of sphingolipid-metabolizing transcript levels were between cancer Cancer to benign were to study the between and the metabolites carcinomas featured the in sphinganine, sphingosine, and all of which could be by a in SGPL1, the for of sphingolipids cancer types were by a in SMs, which could be by a in for CERT1 to the of ceramide to the for SM K. 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Google and our of in tissues featuring low levels of is with this We that lung cancers and sphingolipid While sphingolipids and SMs are could be for we a upregulation of in all adenocarcinomas featured high levels of which is by of FA2H in this cancer carcinoma featured the in several including which associated with the upregulation of compared with all the other cancer As a whole, our study associated with sphingolipid

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