Dataset Information

Whole-genome characterization of lung adenocarcinomas lacking the RTK/RAS/RAF pathway.

ABSTRACT: RTK/RAS/RAF pathway alterations (RPAs) are a hallmark of lung adenocarcinoma (LUAD). In this study, we use whole-genome sequencing (WGS) of 85 cases found to be RPA(-) by previous studies from The Cancer Genome Atlas (TCGA) to characterize the minority of LUADs lacking apparent alterations in this pathway. We show that WGS analysis uncovers RPA(+) in 28 (33%) of the 85 samples. Among the remaining 57 cases, we observe focal deletions targeting the promoter or transcription start site of STK11 (n = 7) or KEAP1 (n = 3), and promoter mutations associated with the increased expression of ILF2 (n = 6). We also identify complex structural variations associated with high-level copy number amplifications. Moreover, an enrichment of focal deletions is found in TP53 mutant cases. Our results indicate that RPA(-) cases demonstrate tumor suppressor deletions and genome instability, but lack unique or recurrent genetic lesions compensating for the lack of RPAs. Larger WGS studies of RPA(-) cases are required to understand this important LUAD subset.

SUBMITTER: Carrot-Zhang J

PROVIDER: S-EPMC8009291 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Whole-genome characterization of lung adenocarcinomas lacking the RTK/RAS/RAF pathway.

Carrot-Zhang Jian J Yao Xiaotong X Devarakonda Siddhartha S Deshpande Aditya A Damrauer Jeffrey S JS Silva Tiago Chedraoui TC Wong Christopher K CK Choi Hyo Young HY Felau Ina I Robertson A Gordon AG Castro Mauro A A MAA Bao Lisui L Rheinbay Esther E Liu Eric Minwei EM Trieu Tuan T Haan David D Yau Christina C Hinoue Toshinori T Liu Yuexin Y Shapira Ofer O Kumar Kiran K Mungall Karen L KL Zhang Hailei H Lee Jake June-Koo JJ Berger Ashton A Gao Galen F GF Zhitomirsky Binyamin B Liang Wen-Wei WW Zhou Meng M Moorthi Sitapriya S Berger Alice H AH Collisson Eric A EA Zody Michael C MC Ding Li L Cherniack Andrew D AD Getz Gad G Elemento Olivier O Benz Christopher C CC Stuart Josh J Zenklusen J C JC Beroukhim Rameen R Chang Jason C JC Campbell Joshua D JD Hayes D Neil DN Yang Lixing L Laird Peter W PW Weinstein John N JN Kwiatkowski David J DJ Tsao Ming S MS Travis William D WD Khurana Ekta E Berman Benjamin P BP Hoadley Katherine A KA Robine Nicolas N Meyerson Matthew M Govindan Ramaswamy R Imielinski Marcin M

Cell reports 20210201 5

RTK/RAS/RAF pathway alterations (RPAs) are a hallmark of lung adenocarcinoma (LUAD). In this study, we use whole-genome sequencing (WGS) of 85 cases found to be RPA(-) by previous studies from The Cancer Genome Atlas (TCGA) to characterize the minority of LUADs lacking apparent alterations in this pathway. We show that WGS analysis uncovers RPA(+) in 28 (33%) of the 85 samples. Among the remaining 57 cases, we observe focal deletions targeting the promoter or transcription start site of STK11 (n ...[more]

PMID: 33535033

Similar Datasets

Project description:Activating B-RAF(V600E) (also known as BRAF) kinase mutations occur in ?7% of human malignancies and ?60% of melanomas. Early clinical experience with a novel class I RAF-selective inhibitor, PLX4032, demonstrated an unprecedented 80% anti-tumour response rate among patients with B-RAF(V600E)-positive melanomas, but acquired drug resistance frequently develops after initial responses. Hypotheses for mechanisms of acquired resistance to B-RAF inhibition include secondary mutations in B-RAF(V600E), MAPK reactivation, and activation of alternative survival pathways. Here we show that acquired resistance to PLX4032 develops by mutually exclusive PDGFR? (also known as PDGFRB) upregulation or N-RAS (also known as NRAS) mutations but not through secondary mutations in B-RAF(V600E). We used PLX4032-resistant sub-lines artificially derived from B-RAF(V600E)-positive melanoma cell lines and validated key findings in PLX4032-resistant tumours and tumour-matched, short-term cultures from clinical trial patients. Induction of PDGFR? RNA, protein and tyrosine phosphorylation emerged as a dominant feature of acquired PLX4032 resistance in a subset of melanoma sub-lines, patient-derived biopsies and short-term cultures. PDGFR?-upregulated tumour cells have low activated RAS levels and, when treated with PLX4032, do not reactivate the MAPK pathway significantly. In another subset, high levels of activated N-RAS resulting from mutations lead to significant MAPK pathway reactivation upon PLX4032 treatment. Knockdown of PDGFR? or N-RAS reduced growth of the respective PLX4032-resistant subsets. Overexpression of PDGFR? or N-RAS(Q61K) conferred PLX4032 resistance to PLX4032-sensitive parental cell lines. Importantly, MAPK reactivation predicts MEK inhibitor sensitivity. Thus, melanomas escape B-RAF(V600E) targeting not through secondary B-RAF(V600E) mutations but via receptor tyrosine kinase (RTK)-mediated activation of alternative survival pathway(s) or activated RAS-mediated reactivation of the MAPK pathway, suggesting additional therapeutic strategies.

Project description:The RTK/RAS pathway is an oncogenic signaling pathway for which many targeted drugs have been developed; however, survival remains poor. A combination of targeted therapy and immunotherapy has emerged as an option for improving cancer treatment responses. In this study, on the basis of the expression, survival, single nucleotide variation (SNV), copy number variation (CNV), and methylation data of lung adenocarcinoma (LUAD) from The Cancer Genome Atlas database, we comprehensively analyzed the genomic changes in the RTK/RAS pathway and their associations with tumor-infiltrating lymphocytes (TIL) and prognosis in LUAD to provide the genomics landscape of RTK/RAS with TIL and prognosis. We found that two rarely mutated genes, mitogen-activated protein kinase kinase 1 and insulin-like growth factor 1 receptor, were significantly associated with the worse survival of patients with LUAD. Patients with LUAD and co-mutation of KRAS proto-oncogene (KRAS) and neurofibromin 1 genes had worse survival, and the underlying mechanism could be insufficient for protein synthesis and intracellular signal deactivation. Methylation of the Rac family small GTPase 1 (RAC1) was associated with better survival. The SNVs of the top mutated genes, including epidermal growth factor receptor (12.7%), neurotrophic receptor tyrosine kinase 3 (7.8%), erb-b2 receptor tyrosine kinase 4 (8.5%), and KRAS (29.6%), were associated with T cell exhaustion in LUAD. To construct nomograms, we further screened the genes whose genomic changes were closely associated with survival and immune infiltration. The nomograms performed well in predicting disease-specific survival (DSS) with a concordance index of 0.7 (0.589, 0.811) and overall survival with a concordance index of 0.689 (0.603, 0.775) in test set; they also showed good correspondence between actual and ideal nomogram predictions. Tumor stage, RAC1 methylation, and type 1 regulatory T cells greatly contributed to DSS and OS nomograms. In summary, we provided a comprehensive genomic profile of the RTK/RAS pathway in LUAD and its association with immune cell infiltration and prognosis of LUAD. This profile would serve as a basis for developing better therapeutic strategies, improving patient prognosis, and understanding the mechanisms of immune disturbance from the perspective of oncogenic pathways of LUAD.

Project description:Alternative splicing analysis of laser micro-dissected lung dysplasia RNA samples Lung dysplasia is a precancerous condition with high risk of malignant transformation. Little is known about alternative spliced (AS) genes in dysplasia. We therefore investigated laser micro-dissected microscopic foci of non-contaminant dysplasia and/or lung adenocarcinoma of c-Raf transgenic mice and searched genome wide for AS genes using exon arrays. Notably, bioinformatics defined 34 and 36 AS genes in the comparison dysplasia versus transgenic unaltered and non-transgenic lung tissue while the comparison adenocarcinoma versus transgenic unaltered and non-transgenic lung tissue revealed 54 and 56 genes, respectively. So far only 6 of these were reported for lung cancer. Importantly, dysplasia related AS genes were also regulated in lung cancer to suggest a role in disease onset. Next to exon skipping/inclusion alternative splicing at the 3’ and 5’ was common and included genes of the splicing regulatory pathway. Disease dependent changes of variant transcripts were confirmed by RT-PCR while Western blotting identified alternative splicing to modulate protein levels of AS genes. For the AS genes Add3, Cast, Osbpl6, Nedd4l, Numb, Picalm and Slk transcript and protein level agreed well, whereas for Arhgef11, Clstn1, Dlg1, Dock9, Mbnl2, Mfge8, Npnt, Pdlim5, Ppp2r5c, Tjp1 notable differences in the abundance of variant transcripts were observed by RT-PCR and gel electrophoresis. Moreover, expression of individual variants differed between dysplasia and carcinoma to suggest their disease dependent regulation. Western blotting of IQGAP1, MYO6, PTPRM, RABGAP1L and RAD50 confirmed significant regulation of isoforms in lung cancer as compared to non-transgenic, transgenic unaltered and dysplastic lung tissue. For 46 AS genes expression of the non-variant protein was reported in human lung cancer (www.proteinatlas.org) and for 13 of these, cancer related AS events are known. Overall, new insight into lung dysplasia was obtained with 43 new cancer related AS genes to aid diagnosis and molecular intervention strategies.

Project description:Alternative splicing analysis of laser micro-dissected lung dysplasia RNA samples Lung dysplasia is a precancerous condition with high risk of malignant transformation. Little is known about alternative spliced (AS) genes in dysplasia. We therefore investigated laser micro-dissected microscopic foci of non-contaminant dysplasia and/or lung adenocarcinoma of c-Raf transgenic mice and searched genome wide for AS genes using exon arrays. Notably, bioinformatics defined 34 and 36 AS genes in the comparison dysplasia versus transgenic unaltered and non-transgenic lung tissue while the comparison adenocarcinoma versus transgenic unaltered and non-transgenic lung tissue revealed 54 and 56 genes, respectively. So far only 6 of these were reported for lung cancer. Importantly, dysplasia related AS genes were also regulated in lung cancer to suggest a role in disease onset. Next to exon skipping/inclusion alternative splicing at the 3M-bM-^@M-^Y and 5M-bM-^@M-^Y was common and included genes of the splicing regulatory pathway. Disease dependent changes of variant transcripts were confirmed by RT-PCR while Western blotting identified alternative splicing to modulate protein levels of AS genes. For the AS genes Add3, Cast, Osbpl6, Nedd4l, Numb, Picalm and Slk transcript and protein level agreed well, whereas for Arhgef11, Clstn1, Dlg1, Dock9, Mbnl2, Mfge8, Npnt, Pdlim5, Ppp2r5c, Tjp1 notable differences in the abundance of variant transcripts were observed by RT-PCR and gel electrophoresis. Moreover, expression of individual variants differed between dysplasia and carcinoma to suggest their disease dependent regulation. Western blotting of IQGAP1, MYO6, PTPRM, RABGAP1L and RAD50 confirmed significant regulation of isoforms in lung cancer as compared to non-transgenic, transgenic unaltered and dysplastic lung tissue. For 46 AS genes expression of the non-variant protein was reported in human lung cancer (www.proteinatlas.org) and for 13 of these, cancer related AS events are known. Overall, new insight into lung dysplasia was obtained with 43 new cancer related AS genes to aid diagnosis and molecular intervention strategies. We analyzed and compared dysplastic (n=4) and adenocarcinoma (n=4) lesions and with transgenic but unaltered (n=4) and non-transgenic (n=5) lung tissue obtained from SPC/c-Raf transgenic mice with aid of laser micro dissection pressure catapulted (LMPC) technique. Dysplasia is a pre-neoplastic condition and developed at 5 month of age in the proposed mouse model. LMPC provides precise microscopic lesion collection without contamination. The RNA samples were analyzed using the Affymetrix Mouse Exon 1.0 ST platform. Alternative splicing was analyzed using Biotique XRAY tool. No technical replicates were performed.

Dataset Information

Whole-genome characterization of lung adenocarcinomas lacking the RTK/RAS/RAF pathway.

Publications

Whole-genome characterization of lung adenocarcinomas lacking the RTK/RAS/RAF pathway.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets