Immunohistochemical validation study of 15-gene biomarker panel predictive of benefit from adjuvant chemotherapy in resected non-small-cell lung cancer: analysis of JBR.10
ESMO OPEN
Authors: Grieve, Stacy; Ding, Keyue; Moore, Jonathan; Finniss, Mathew; Ray, Ayush; Lees, Miranda; Hossain, Faisal; Murugesan, Alli; Agar, Jane; Acar, Cenk; Taylor, James; Shepherd, Frances A.; Reiman, Tony
Abstract
Objective There are no validated approaches to predict benefit from adjuvant chemotherapy for resected patients with non-small-cell lung cancer (NSCLC). The aim of this study was to translate a 15-gene mRNA expression profile published by Zhu et al, shown to be prognostic and predictive of benefit, into a readily applicable immunohistochemistry (IHC) panel. Methods For seven of the genes in the gene expression profile (GEP) for which suitable commercial antibodies were available, we semiquantitatively assessed the IHC expression and prognostic significance for 173 patients treated at the Saint John Regional Hospital (SJRH). Cut-offs for high and low expression were defined for each marker and applied to IHC scores from 291 of the 482 patients in JBR.10, including patients on both the adjuvant chemotherapy and observation arms. The prognostic and predictive value of these markers on overall survival (OS) or recurrence-free survival (RFS) was assessed by Cox regression models. Results In the SJRH cohort, in 62 patients with resected stage II-III NSCLC, the prognostic significance of IHC assays for four proteins were concordant with Zhu's GEP results. Low FOSL2 (OS, HR=0.15; p=0.0001; RFS, HR=0.14; p<0.0001) and high STMN2 (RFS, HR=2.501; p=0.0197) were adverse prognostic factors. Low ATP1B1 and low TRIM14 expression trended toward worse OS and RFS. Validation of these markers with JBR.10 patients failed to show prognostic significance either individually or in combined risk classifications. Additionally, the interaction between these markers and chemotherapy treatment in predicting OS (FOSL2, p=0.52; STMN2 p=0.14; ATP1B1, p=0.33; TRIM14, p=0.81) or RFS (FOSL2, p=0.63; STMN2, p=0.12; ATP1B1, p=0.66; TRIM14, p=0.57) did not reach significance, individually or in combination panels. Conclusions Zhu's GEP could not be translated into an IHC panel predictive of benefit from adjuvant chemotherapy. Future predictive biomarker analysis in the adjuvant NSCLC setting may need to focus on novel therapies.
Alternative splicing regulates mouse embryonic stem cell pluripotency and differentiation
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Authors: Salomonis, Nathan; Schlieve, Christopher R.; Pereira, Laura; Wahlquist, Christine; Colas, Alexandre; Zambon, Alexander C.; Vranizan, Karen; Spindler, Matthew J.; Pico, Alexander R.; Cline, Melissa S.; Clark, Tyson A.; Williams, Alan; Blume, John E.; Samal, Eva; Mercola, Mark; Merrill, Bradley J.; Conklin, Bruce R.
Abstract
Two major goals of regenerative medicine are to reproducibly transform adult somatic cells into a pluripotent state and to control their differentiation into specific cell fates. Progress toward these goals would be greatly helped by obtaining a complete picture of the RNA isoforms produced by these cells due to alternative splicing (AS) and alternative promoter selection (APS). To investigate the roles of AS and APS, reciprocal exon-exon junctions were interrogated on a genome-wide scale in differentiating mouse embryonic stem (ES) cells with a prototype Affymetrix microarray. Using a recently released open-source software package named AltAnalyze, we identified 144 genes for 170 putative isoform variants, the majority (67%) of which were predicted to alter protein sequence and domain composition. Verified alternative exons were largely associated with pathways of Wnt signaling and cell-cycle control, and most were conserved between mouse and human. To examine the functional impact of AS, we characterized isoforms for two genes. As predicted by AltAnalyze, we found that alternative isoforms of the gene Serca2 were targeted by distinct microRNAs (miRNA-200b, miRNA-214), suggesting a critical role for AS in cardiac development. Analysis of the Wnt transcription factor Tcf3, using selective knockdown of an ES cell-enriched and characterized isoform, revealed several distinct targets for transcriptional repression (Stmn2, Ccnd2, Atf3, Klf4, Nodal, and Jun) as well as distinct differentiation outcomes in ES cells. The findings herein illustrate a critical role for AS in the specification of ES cells with differentiation, and highlight the utility of global functional analyses of AS.