title: Proteomic profile of KSR1-regulated signalling in response to genotoxic agents in breast cancer.
abstract: Kinase suppressor of Ras 1 (KSR1) has been implicated in tumorigenesis in multiple cancers, including skin, pancreatic and lung carcinomas. However, our recent study revealed a role of KSR1 as a tumour suppressor in breast cancer, the expression of which is potentially correlated with chemotherapy response. Here, we aimed to further elucidate the KSR1-regulated signalling in response to genotoxic agents in breast cancer. Stable isotope labelling by amino acids in cell culture (SILAC) coupled to high-resolution mass spectrometry (MS) was implemented to globally characterise cellular protein levels induced by KSR1 in the presence of doxorubicin or etoposide. The acquired proteomic signature was compared and GO-STRING analysis was subsequently performed to illustrate the activated functional signalling networks. Furthermore, the clinical associations of KSR1 with identified targets and their relevance in chemotherapy response were examined in breast cancer patients. We reveal a comprehensive repertoire of thousands of proteins identified in each dataset and compare the unique proteomic profiles as well as functional connections modulated by KSR1 after doxorubicin (Doxo-KSR1) or etoposide (Etop-KSR1) stimulus. From the up-regulated top hits, several proteins, including STAT1, ISG15 and TAP1 are also found to be positively associated with KSR1 expression in patient samples. Moreover, high KSR1 expression, as well as high abundance of these proteins, is correlated with better survival in breast cancer patients who underwent chemotherapy. In aggregate, our data exemplify a broad functional network conferred by KSR1 with genotoxic agents and highlight its implication in predicting chemotherapy response in breast cancer.
authors.affiliation: Division of Cancer, Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital Campus, ICTEM Building, Du Cane Road, London, W12 ONN, UK, h.zhang10@imperial.ac.uk.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Nicos
authors.initials: N
authors.lastname: Angelopoulos
authors.forename: Yichen
authors.initials: Y
authors.lastname: Xu
authors.forename: Arnhild
authors.initials: A
authors.lastname: Grothey
authors.forename: Joao
authors.initials: J
authors.lastname: Nunes
authors.forename: Justin
authors.initials: J
authors.lastname: Stebbing
authors.forename: Georgios
authors.initials: G
authors.lastname: Giamas
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000401:mortality; D045744:Cell Line, Tumor; D016000:Cluster Analysis; D004317:Doxorubicin / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D053263:Gene Regulatory Networks; D006801:Humans; D009153:Mutagens / Q000494:pharmacology*; D011379:Prognosis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020543:Proteome; D040901:Proteomics / Q000379:methods; D015398:Signal Transduction / Q000187:drug effects*; D016019:Survival Analysis
chemical_list: D000970:Antineoplastic Agents; D009153:Mutagens; D020543:Proteome; D005047:Etoposide; D004317:Doxorubicin; D011494:Protein Kinases; C097199:KSR-1 protein kinase