Project description:To development our gene expression approach, we have employed whole genome microarray expression profiling as a discovery platform to identify genes potentialy regulated by the transcription factor MAX.Human SCLC cell lines waere analyzed for mutations at the MAX locus. Those cell lines that were found mutated in MAX and showed no MAX protein expression were used as a models to restore the expression of MAX transcription factor, and Identify MAX signature on Human SCLC.
Project description:To development our gene expression approach, we have employed whole genome microarray expression profiling as a discovery platform to identify genes potentialy regulated by the transcription factor MAX.Human SCLC cell lines waere analyzed for mutations at the MAX locus. Those cell lines that were found mutated in MAX and showed no MAX protein expression were used as a models to restore the expression of MAX transcription factor, and Identify MAX signature on Human SCLC. Human SCLC cell lines were hybridyzed in the following manner according for different conditions (Mock -Ø, MAX, shBRG1, MAX-shBRG1): 3 different biological samples for Mock, 3 different biological samples for MAX, 3 different samples for shBRG1 and 3 replicates of the same sample for MAX-shBRG1.
Project description:The MYC axis is commonly disrupted in cancer, mostly by activation of the MYC family of oncogenes, but also by genetic inactivation of MAX, the obligate partner of MYC, and of the MAX partner, MGA, both of which are members of the polycomb repressive complex, ncPRC1.6. While the oncogenic properties of the MYC family have been extensively studied, the tumor suppressor functions of MAX and MGA and the role of the MYC genes in MAX-mutant cells remain unclear. To address these knowledge gaps, we used chromatin immunoprecipitation, RNA-sequencing and mass spectrometry-based proteomic analysis in MAX-restituted and MYC oncogenic-transformed cell lines derived from human small cell lung cancer (SCLC), which is a high-grade neuroendocrine type of lung cancer. We found that MAX-mutant SCLC cells express ASCL1 and ASCL1-dependent targets, implying that these cells belong to the ASCL1-dependent group of SCLCs. In the absence of MAX, even after ectopic overexpression of MYC, we found no recruitment of MYC to the DNA. Furthermore, MAX reconstitution triggered pro-differentiation expression profiles that shifted when MAX and oncogenic MYC were co-expressed. Although ncPRC1.6 could be formed, the lack of MAX restricted global MGA occupancy, selectively driving its recruitment towards E2F6 motifs. Conversely, MAX restitution enhanced MGA occupancy and global gene repression of genes involved in different functions, including stem-cell and DNA repair/replication. Our data reveal that MAX-mutant SCLCs have ASCL1 characteristics, and are MYC-independent, and that their oncogenic features include deficient ncPRC1.6-mediated gene repression.
Project description:To identify the immune peptides in SCLC tumour cells that can be processed and presented by HLA-I, we performed LC–MS/MS analysis on 11 SCLC cell lines, representing the heterogeneity of SCLC subtypes. Ten of the cell lines were confirmed positive for HLA-I, and one was HLA-I-deficient. To analyse cell surface antigens on the HLA-I-deficient cells, PBMCs isolated from healthy blood donors were treated with DMS53 cell lysate and matured into DCs to present the tumour cell antigens.