bioRxiv Science⌕ Search

Biology subjects

Lalou, C.

Publications and source records attributed to Lalou, C..

2 recordsLinked to original sources

Proteomic profiling of advanced hepatocellular carcinoma identifies predictive signatures of response to treatments

PurposeHepatocellular carcinoma (HCC) is the most common form of liver cancer with a bad prognosis in case of advanced HCC, only eligible for palliative systemic therapies. After a decade of exclusive sorafenib monotherapy, with a response rate of <10%, the advent of immunotherapies represents a revolution in HCC. The combination of atezolizumab/bevacizumab is recommended as the first-line systemic treatment, with a response rate around 30%. However, there are currently no predictive factors for response to these treatment options. Experimental DesignWe profiled, by high-resolution mass spectrometry-based proteomics combined with machine learning analysis, a selected cohort of fixed biopsies of advanced HCC. We grouped subjects according to their objective response to treatments, corresponded to a tumor regression vs tumor progression at 4 months after treatment. ResultsWe generated a proteome database of 50 selected HCC samples. We compared the relative protein abundance between tumoral and non-tumoral liver tissues from advanced HCC patients treated. The clear distinction of these two groups for each treatment is based on deregulation for 141 protein or 87 for atezolizumab/bevacizumab and sorafenib treatment, respectively. These specific proteomic signatures were sufficient to predict the response to treatment, and revealed biological pathways involved in treatments resistance. Particularly, we validated a shift in tumor cell metabolism with an immunosuppressive environment involved in the resistance to atezolizumab/bevacizumab combination. ConclusionsWe performed an in-depth analysis of quantitative proteomic data from HCC biopsies to predict the treatment response to advanced HCC giving the ability to optimize patient management.

cancer biology↗

The E3 ubiquitin ligase FBXL6 controls the quality of newly synthesized mitochondrial ribosomal proteins

The large majority of mitochondrial proteins is synthesized in the cytosol and then imported to the organelle. To ensure proper mitochondrial functions, the quality of these proteins needs to be guaranteed. Here, we show that the E3 ubiquitin ligase F-box/LRR-repeat protein 6 (FBXL6) participates to the quality of these mitochondrial proteins at the level of the cytosolic translation. We found that lack of FBXL6 has severe effects including mitochondrial ribosomal protein aggregations, altered mitochondrial metabolism and inhibited cell cycle progression in oxidative conditions. FBXL6 was found to interact specifically with ribosomal-associated quality control proteins and chaperones involved in the regulation of newly synthesized proteins and also it preferentially binds newly synthesized mitochondrial ribosomal proteins. Consistently, deletion of the RQC protein, NEMF or HSP70-family chaperone HSPA1A impedes FBXL6 interaction with its substrate. In addition, cells lacking FBXL6 display altered degradation of defective mitochondrial ribosomal protein containing C-terminal alanyl-threonyl extension.

cell biology↗