Zinc deficiency is associated with impaired antiviral response, cytokine releasing syndrome (CRS), and acute respiratory distress syndrome. Notably, similar complications are being observed during severe SARS-CoV-2 infection. We conducted a prospective, single-center, observational study in a tertiary university hospital (CUB-Hôpital Erasme, Brussels) to address the zinc status, the association between the plasma zinc concentration, development of CRS, and the clinical outcomes in PCR-confirmed and hospitalized COVID-19 patients. One hundred and thirty-nine eligible patients were included between May 2020 and November 2020 (median age of 65 years [IQR = 54, 77]). Our cohort's median plasma zinc concentration was 57 µg/dL (interquartile range [IQR] = 45, 67) compared to 74 µg/dL (IQR = 64, 84) in the retrospective non-COVID-19 control group (N = 1513; p <.001). Markedly, the absolute majority of COVID-19 patients (96%) were zinc deficient (<80 µg/dL). The median zinc concentration was lower in patients with CRS compared to those without CRS (-5 µg/dL; 95% CI = -10.5, 0.051; p = 0.048). Among the tested outcomes, zinc concentration is significantly correlated with only the length of hospital stay (rho = -0.19; p = 0.022), but not with mortality or morbidity. As such, our findings do not support the role of zinc as a robust prognostic marker among hospitalized COVID-19 patients who in our cohort presented a high prevalence of zinc deficiency. It might be more beneficial to explore the role of zinc as a biomarker for assessing the risk of developing a tissue-damaging CRS and predicting outcomes in patients diagnosed with COVID-19 at the early stage of the disease.

Non-small cell lung cancer (NSCLC) patients harboring activating mutations in epidermal growth factor receptor (EGFR) are sensitive to therapy with EGFR tyrosine kinase inhibitors (TKI). Despite remarkable clinical responses using EGFR TKI, surviving drug tolerant cells serve as a reservoir from which drug resistant tumors may emerge. This study addresses the need for improved efficacy of EGFR TKI by identifying targets involved in functional drug tolerance against them. To this aim, a high-throughput siRNA kinome screen was performed using two EGFR TKI-sensitive EGFR-mutant NSCLC cell lines in the presence/absence of the second-generation EGFR TKI afatinib. From the screen, Serine/Threonine/Tyrosine Kinase 1 (STYK1) was identified as a target that when downregulated potentiates the effects of EGFR inhibition in vitro. We found that chemical inhibition of EGFR combined with the siRNA-mediated knockdown of STYK1 led to a significant decrease in cancer cell viability and anchorage-independent cell growth. Further, we show that STYK1 selectively interacts with mutant EGFR and that the interaction is disrupted upon EGFR inhibition. Finally, we identified fibroblast growth factor 1 (FGF1) as a downstream effector of STYK1 in NSCLC cells. Accordingly, downregulation of STYK1 counteracted the afatinib-induced upregulation of FGF1. Altogether, we unveil STYK1 as a valuable target to repress the pool of surviving drug tolerant cells arising upon EGFR inhibition. Co-targeting of EGFR and STYK1 could lead to a better overall outcome for NSCLC patients.

The tumor suppressor gene TP53 is the most frequently mutated gene in various cancers. Unlike other tumor suppressors, TP53 is mostly hit by missense mutations, of which more than 2,000 have been described in cancer patients. To take advantage of TP53 mutation status for personalized therapy, a deeper knowledge of the functional ramifications of specific mutations is required as evidence of the functional heterogeneity of mutant p53 proteins mounts. Here, we report on a CRISPR-based saturation mutagenesis screen of 9,225 variants expressed from the endogenous TP53 gene locus of a cancer cell. By tracking changes in the abundance of individual variants in response to specific p53-pathway stimulation, we were able to construct high-resolution functional activity maps of the TP53 mutome, covering ~94.5% of all cancer-associated missense mutations. The results demonstrate the impact of individual mutations on tumor cell fitness with unprecedented precision and coverage, even revealing underlying mechanisms such as apoptosis. The high discriminatory power also resolves subtle loss-of-function phenotypes and highlights a subset of mutants as particularly promising targets for pharmacological reactivation. Moreover, the data offer intriguing insight into the role of aberrant splicing and nonsense-mediated mRNA decay in clearing truncated proteins due to not only nonsense, frameshift, and splice-site mutations but also missense and synonymous mutations. Surprisingly, no missense mutation provided an immediate proliferative advantage over a null mutation. Nonetheless, cells with a missense, but not null mutations, acquired pro-metastatic properties after prolonged growth in mice, emphasizing the significance of mutant p53-directed clonal evolution in the progression of tumors towards metastasis.