Singh, S. R. | bioRxiv Science

bioRxiv2022

Brief Report: Prognostic relevance of 3q amplification in squamous cell carcinoma of the lung

IntroductionAmplification of 3q is the most common genetic alteration identified in squamous cell carcinoma of the lung (LUSC) with the most frequent amplified region being 3q26-3q28. MethodsIn this analysis, we aim to describe the prognostic relevance of 3q by focusing on a minimal common region (MCR) of amplification within 3q constituted by 25 genes. We analyzed 511 cases of LUSC from The Cancer Genome Atlas (TCGA) and included 476 in the final analysis. ResultsWe identified a 25-gene MCR that was amplified in 221 (44.3%) cases and was associated with better disease specific-survival (DSS) (NR versus 9.25 years; 95% CI [5.24-NR]; log-rank p=0.011) and a progression-free interval (PFI) of 8 years (95% CI [5.1-NR]) versus 4.9 years (95% [3.5-NR]) (Log-rank p=0.020). Multivariable analysis revealed MCR amplification was associated with improved DSS and PFI. ConclusionAmplification of the 25-gene MCR within 3q was present in 44% of this cohort mainly composed of Caucasian patients with early-stage LUSC. This analysis is a strong indicator of the prognostic relevance of the 25-gene MCR within 3q. We are further evaluating its prognostic relevance in a racially diverse patient population with advanced LUSC.

genomics↗

bioRxiv2021

ACTN2 missense variant causes proteopathy in human iPSC-derived cardiomyocytes

Genetic variants in -actinin-2 (ACTN2) are associated with several forms of (cardio)myopathy. We previously reported a heterozygous missense (c.740C>T) ACTN2 gene variant, associated with hypertrophic cardiomyopathy, and characterized by an electro-mechanical phenotype in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Here, we created with CRISPR/Cas9 genetic tools two heterozygous functional knock-out hiPSC lines with a second wild-type (ACTN2wt) and missense ACTN2 (ACTN2mut) allele, respectively. We evaluated their impact on cardiomyocyte structure and function, using a combination of different technologies, including immunofluorescence and live cell imaging, RNA-seq, and mass spectrometry. This study showed that ACTN2mut present a higher percentage of multinucleation, protein aggregation, hypertrophy, myofibrillar disarray and activation of both the ubiquitin-proteasome system and the autophagy-lysosomal pathway as compared to ACTN2wt in 2D-cultured hiPSC-CMs. Furthermore, the expression of ACTN2mut was associated with a marked reduction of sarcomere-associated protein levels in 2D-cultured hiPSC-CMs and force impairment in engineered heart tissues. In conclusion, our study highlights the activation of proteolytic systems in ACTN2mut hiPSC-CMs likely to cope with ACTN2 aggregation and therefore directs towards proteopathy as an additional cellular pathology caused by this ACTN2 variant, which may contribute to human ACTN2-associated cardiomyopathies.

cell biology↗