In vivo vulnerabilities to GPX4 and HDAC inhibitors in drug-persistent versus drug-resistant BRAFV600E lung adenocarcinoma.

The current targeted therapy for BRAFV600E-mutant lung cancer consists of a dual blockade of RAF/MEK kinases often combining dabrafenib/trametinib (D/T). This regimen extends survival when compared to single-agent treatments, but disease progression is unavoidable. By using whole-genome CRISPR screening and RNA sequencing, we characterize the vulnerabilities of both persister and D/T-resistant cellular models. Oxidative stress together with concomitant induction of antioxidant responses is boosted by D/T treatment. However, the nature of the oxidative damage, the choice of redox detoxification systems, and the resulting therapeutic vulnerabilities display stage-specific differences. Persister cells suffer from lipid peroxidation and are sensitive to ferroptosis upon GPX4 inhibition in vivo. Biomarkers of lipid peroxidation are detected in clinical samples following D/T treatment. Acquired alterations leading to mitogen-activated protein kinase (MAPK) reactivation enhance cystine transport to boost GPX4-independent antioxidant responses. Similarly to BRAFV600E-mutant melanoma, histone deacetylase (HDAC) inhibitors decrease D/T-resistant cell viability and extend therapeutic response in vivo.

Valine aminoacyl-tRNA synthetase promotes therapy resistance in melanoma.

Transfer RNA dynamics contribute to cancer development through regulation of codon-specific messenger RNA translation. Specific aminoacyl-tRNA synthetases can either promote or suppress tumourigenesis. Here we show that valine aminoacyl-tRNA synthetase (VARS) is a key player in the codon-biased translation reprogramming induced by resistance to targeted (MAPK) therapy in melanoma. The proteome rewiring in patient-derived MAPK therapy-resistant melanoma is biased towards the usage of valine and coincides with the upregulation of valine cognate tRNAs and of VARS expression and activity. Strikingly, VARS knockdown re-sensitizes MAPK-therapy-resistant patient-derived melanoma in vitro and in vivo. Mechanistically, VARS regulates the messenger RNA translation of valine-enriched transcripts, among which hydroxyacyl-CoA dehydrogenase mRNA encodes for a key enzyme in fatty acid oxidation. Resistant melanoma cultures rely on fatty acid oxidation and hydroxyacyl-CoA dehydrogenase for their survival upon MAPK treatment. Together, our data demonstrate that VARS may represent an attractive therapeutic target for the treatment of therapy-resistant melanoma.

Atezolizumab plus modified docetaxel, cisplatin, and fluorouracil as first-line treatment for advanced anal cancer (SCARCE C17-02 PRODIGE 60): a randomised, non-comparative, phase 2 study.

BACKGROUND: The modified docetaxel, cisplatin, and fluorouracil (mDCF) regimen has shown efficacy and safety as first-line treatment for advanced squamous cell carcinoma of the anus, making it a standard regimen. Inhibitors of programmed cell death protein 1 and its ligand, such as pembrolizumab, nivolumab, retifanlimab, avelumab, and atezolizumab, have shown some antitumour activity as monotherapy in advanced squamous cell carcinoma of the anus that is refractory to chemotherapy. This phase 2 study evaluated the combination of mDCF and atezolizumab as first-line treatment in advanced squamous cell carcinoma of the anus. METHODS: In this randomised, open-label, non-comparative, phase 2 study, participants from 21 centres (academic, private, and community hospitals and cancer research centres) across France with chemo-naive, metastatic, or unresectable locally advanced recurrent squamous cell carcinoma of the anus, aged 18 years or older, and with an Eastern Cooperative Oncology Group performance status of 0 or 1, were randomly allocated (2:1) to receive either atezolizumab (800 mg intravenously every 2 weeks up to 1 year) plus mDCF (eight cycles of 40 mg per m2 docetaxel and 40 mg per m2 cisplatin on day 1 and 1200 mg per m2 per day of fluorouracil for 2 days, every 2 weeks intravenously; group A) or mDCF alone (group B). Randomisation was done centrally using a minimisation technique and was stratified by age (<65 years vs ≥65 years) and disease status. The primary endpoint was investigator-assessed 12-month progression-free survival in the modified intention-to-treat population in group A (35% for the null hypothesis and 50% for the alternative hypothesis). This trial is registered with ClinicalTrials.gov, NCT03519295, and is closed to new participants. FINDINGS: 97 evaluable participants (64 in group A and 33 in group B) were enrolled between July 3, 2018, and Aug 19, 2020. The median follow-up was 26·5 months (95% CI 24·8-28·4). The median age of participants was 64·1 years (IQR 56·2-71·6), and 71 (73%) were female. 12-month progression-free survival was 45% (90% CI 35-55) in group A and 43% (29-58) in group B. In participants with a PD-L1 combined positive score of 5 or greater, 12-month progression-free survival was 70% (95% CI 47-100) in group A and 40% (19-85) in group B (interaction p=0·051) Both groups showed high compliance. Adverse events of grade 3 or higher were observed in 39 (61%) participants in group A and 14 (42%) in group B. The most common grade 3-4 adverse events were neutropenia (nine [14%] participants in group A vs five [15%] in group B), anaemia (nine [14%] vs one [3%]), fatigue (three [5%] vs four [12%]), and diarrhoea (seven [11%] vs one [3%]). Serious adverse events occurred in 16 (25%) participants in group A and four (12%) in group B, and these were mDCF-related in seven (11%) participants in group A and four (12%) in group B. Atezolizumab-related serious adverse events occurred in nine (14%) participants in group A, including grade 2 infusion-related reaction in three (5%), grade 3 infection in two (3%), and grade 2 colitis, grade 3 acute kidney injury, grade 3 sarcoidosis, and a grade 4 platelet count decrease each in one participant (2%). There were no treatment-related deaths. INTERPRETATION: Despite a higher incidence of adverse events, combining atezolizumab with mDCF is feasible, with similar dose intensity in both groups, although the primary efficacy endpoint was not met. The predictive value of a PD-L1 combined positive score of 5 or greater now needs to be confirmed in future studies. FUNDING: GERCOR, Roche.