eIF3 mRNA selectivity profiling reveals eIF3k as a cancer-relevant regulator of ribosome content.

eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA-selective functions of individual subunits remain poorly defined. Using multiomic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo-complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5'-UTR of RSP15A mRNA negated them. eIF3k and eIF3l are selectively downregulated in response to endoplasmic reticulum and oxidative stress. Supported by mathematical modeling, our data uncover eIF3k-l as a mRNA-specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content, possibly to secure spare translational capacity that can be mobilized during stress.

The Value of Perioperative Immunotherapy for Non-Small Cell Lung Cancer: A Pool- and Meta-Analysis.

Purpose: This study aimed to analyze the efficacy and safety of neoadjuvant and adjuvant immunotherapies for non-small cell lung cancer (NSCLC). Methods: Electronic literature searches were conducted in PubMed, OVID, Web of SCI, Embase, Cochrane Library, and the Chinese National Knowledge Infrastructure databases. The deadline for literature update and retrieval is February 16, 2024. Studies presented at meetings were also screened. Randomized controlled trials (RCTs) and single-arm trials were included, and the data were extracted according to the inclusion and exclusion criteria. Data analysis was performed using Stata (16.0) software. Results: A total of 5850 patients in 11 RCTs and 6 single-arm trial studies involving neoadjuvant and/or adjuvant immune checkpoint inhibitor (ICI)-based therapies were included. Regarding neoadjuvant therapy, the overall complication rate after surgery reached 35% (95% CI, 0.21-0.49). Higher rates of pathological complete response (OR = 7.83; 95% CI, 5.95-10.31; P < .001) and major pathological response (OR = 5.13; 95% CI, 3.56-7.40; P < .001) were found in the resectable NSCLC patients who received neoadjuvant therapy with ICIs combined with chemotherapy compared with patients treated with chemotherapy alone. Of note, compared with chemotherapy, neoadjuvant ICIs combined with chemotherapy significantly improved the overall survival (OS) (HR = 0.65; 95% CI, 0.52-0.82; P < .001) and event-free survival (EFS) (HR = 0.59; 95% CI, 0.52-0.67; P < .001) in patients with resectable NSCLC. Regarding adjuvant therapy, a lower risk of disease progression or death (HR = 0.78; 95% CI, 0.69-0.90; P < .001) was found in the adjuvant ICI group compared with the adjuvant chemotherapy-alone group. In terms of safety, perioperative immunotherapy combined with chemotherapy did not increase toxicity compared with chemotherapy alone. Conclusion: In patients with resectable NSCLC, perioperative immunotherapy was safe and efficacious. Perioperative immunotherapy combined with chemotherapy improved the pathologic response and EFS/DFS/OS over chemotherapy alone without increasing toxicity.

CSN7B defines a variant COP9 signalosome complex with distinct function in DNA damage response.

Mammalian COP9 signalosome (CSN) exists as two variant complexes containing either CSN7A or CSN7B paralogs of unknown functional specialization. Constructing knockout cells, we found that CSN7A and CSN7B have overlapping functions in the deneddylation of cullin-RING ubiquitin ligases. Nevertheless, CSNCSN7B has a unique function in DNA double-strand break (DSB) sensing, being selectively required for ataxia telangiectasia mutated (ATM)-dependent formation of NBS1S343p and γH2AX as well as DNA-damage-induced apoptosis triggered by mitomycin C and ionizing radiation. Live-cell microscopy revealed rapid recruitment of CSN7B but not CSN7A to DSBs. Resistance of CSN7B knockout cells to DNA damage is explained by the failure to deneddylate an upstream DSB signaling component, causing a switch in DNA repair pathway choice with increased utilization of non-homologous end joining over homologous recombination. In mice, CSN7B knockout tumors are resistant to DNA-damage-inducing chemotherapy, thus providing an explanation for the poor prognosis of tumors with low CSN7B expression.