Autophagy-mediated degradation of nuclear envelope proteins during oncogene-induced senescence.

Cellular senescence is a largely irreversible form of cell cycle arrest triggered by various types of damage and stress, including oncogene expression (termed oncogene-induced senescence or OIS). We and others have previously demonstrated that OIS occurs in human benign lesions, acting as a potent tumor suppressor mechanism. Numerous phenotypic changes occur during OIS, both in the cytoplasm and in the nucleus. These include the activation of autophagy, a catabolic process operating in the cytoplasm and downregulation of lamin B1, a component of the nuclear lamina. However, it is unknown whether these changes relate to each other. We discovered that cells entering BRAF(V600E)- or H-RAS(G12V)-induced senescence downregulate not only lamin B1 but also lamin A, as well as several other nuclear envelope (NE) proteins, resulting in an altered NE morphology. Depletion of LMNB1 or LMNA/C was sufficient to recapitulate some OIS features, including cell cycle exit and downregulation of NE proteins. We further found that the global loss of NE proteins is a consequence of their degradation by the autophagy machinery, which occurs concomitantly with autophagy induction and increased lysosomal content and activity. Our study therefore reveals a previously unknown connection between autophagy and the disruption of NE integrity during OIS

Metabolic profiles of regulatory T cells in the tumour microenvironment

Metabolic reprogramming of cancer cells generates a tumour microenvironment (TME) characterised by nutrient restriction, hypoxia, acidity and oxidative stress. While these conditions are unfavourable for infiltrating effector T cells, accumulating evidence suggests that regulatory T cells (Tregs) continue to exert their immune-suppressive functions within the TME. The advantages of Tregs within the TME stem from their metabolic profile. Tregs rely on oxidative phosphorylation for their functions, which can be fuelled by a variety of substrates. Even though Tregs are an attractive target to augment anti-tumour immune responses, it remains a challenge to specifically target intra-tumoral Tregs. We provide a comprehensive review of distinct mechanistic links and pathways involved in regulation of Treg metabolism under the prevailing conditions within the tumour. We also describe how these Tregs differ from the ones in the periphery, and from conventional T cells in the tumour. Targeting pathways responsible for adaptation of Tregs in the tumour microenvironment improves anti-tumour immunity in preclinical models. This may provide alternative therapies aiming at reducing immune suppression in the tumour

Vemurafenib plus cobimetinib in unresectable stage IIIc or stage IV melanoma

Background: In patients with BRAFV600 mutated unresectable stage IIIc or metastatic melanoma, molecular targeted therapy with combined BRAF/MEK-inhibitor vemurafenib plus cobimetinib has shown a significantly improved progression-free survival and overall survival compared to treatment with vemurafenib alone. Nevertheless, the majority of BRAFV600 mutation-positive melanoma patients will eventually develop resistance to treatment. Molecular imaging with 18F-Fluorodeoxyglucose (18F-FDG) PET has been used to monitor response to vemurafenib in some BRAFV600 mutated metastatic melanoma patients, showing a rapid decline of 18F-FDG uptake within 2 weeks following treatment. Furthermore, preliminary results suggest that metabolic alterations might predict the development of resistance to treatment. 18F-Fluoro-3'-deoxy-3'L-fluorothymidine (18F-FLT), a PET-tracer visualizing proliferation, might be more suitable to predict response or resistance to therapy than 18F-FDG. Methods: This phase II, open-label, multicenter study evaluates whether metabolic response to treatment with vemurafenib plus cobimetinib in the first 7 weeks as assessed by 18F-FDG/18F-FLT PET can predict progression-free survival and whether early changes in 18F-FDG/18F-FLT can be used for early detection of treatment response compared to standard response assessment with RECISTv1.1 ceCT at 7 weeks. Ninety patients with BRAFV600E/K mutated unresectable stage IIIc/IV melanoma will be included. Prior to and during treatment all patients will undergo 18F-FDG PET/CT and in 25 patients additional 18F-FLT PET/CT is performed. Histopathological tumor characterization is assessed in a subset of 40 patients to unravel mechanisms of resistance. Furthermore, in all patients, blood samples are taken for pharmacokinetic analysis of vemurafenib/cobimetinib. Outcomes are correlated with PET/CT-imaging and therapy response.

Survival and biomarker analyses from the OpACIN-neo and OpACIN neoadjuvant immunotherapy trials in stage III melanoma

Neoadjuvant ipilimumab plus nivolumab showed high pathologic response rates (pRRs) in patients with macroscopic stage III melanoma in the phase 1b OpACIN () and phase 2 OpACIN-neo () studies(1,2). While the results are promising, data on the durability of these pathologic responses and baseline biomarkers for response and survival were lacking. After a median follow-up of 4 years, none of the patients with a pathologic response (n = 7/9 patients) in the OpACIN study had relapsed. In OpACIN-neo (n = 86), the 2-year estimated relapse-free survival was 84% for all patients, 97% for patients achieving a pathologic response and 36% for nonresponders (P < 0.001). High tumor mutational burden (TMB) and high interferon-gamma-related gene expression signature score (IFN-gamma score) were associated with pathologic response and low risk of relapse; pRR was 100% in patients with high IFN-gamma score/high TMB; patients with high IFN-gamma score/low TMB or low IFN-gamma score/high TMB had pRRs of 91% and 88%; while patients with low IFN-gamma score/low TMB had a pRR of only 39%. These data demonstrate long-term benefit in patients with a pathologic response and show the predictive potential of TMB and IFN-gamma score. Our findings provide a strong rationale for a randomized phase 3 study comparing neoadjuvant ipilimumab plus nivolumab versus standard adjuvant therapy with antibodies against the programmed cell death protein-1 (anti-PD-1) in macroscopic stage III melanoma

Neoadjuvant immunotherapy with nivolumab and ipilimumab induces major pathological responses in patients with head and neck squamous cell carcinoma

Surgery for locoregionally advanced head and neck squamous cell carcinoma (HNSCC) results in 30-50% five-year overall survival. In IMCISION (NCT03003637), a non-randomized phase Ib/IIa trial, 32 HNSCC patients are treated with 2 doses (in weeks 1 and 3) of immune checkpoint blockade (ICB) using nivolumab (NIVO MONO, n = 6, phase Ib arm A) or nivolumab plus a single dose of ipilimumab (COMBO, n = 26, 6 in phase Ib arm B, and 20 in phase IIa) prior to surgery. Primary endpoints are feasibility to resect no later than week 6 (phase Ib) and primary tumor pathological response (phase IIa). Surgery is not delayed or suspended for any patient in phase Ib, meeting the primary endpoint. Grade 3-4 immune-related adverse events are seen in 2 of 6 (33%) NIVO MONO and 10 of 26 (38%) total COMBO patients. Pathological response, defined as the %-change in primary tumor viable tumor cell percentage from baseline biopsy to on-treatment resection, is evaluable in 17/20 phase IIa patients and 29/32 total trial patients (6/6 NIVO MONO, 23/26 COMBO). We observe a major pathological response (MPR, 90-100% response) in 35% of patients after COMBO ICB, both in phase IIa (6/17) and in the whole trial (8/23), meeting the phase IIa primary endpoint threshold of 10%. NIVO MONO's MPR rate is 17% (1/6). None of the MPR patients develop recurrent HSNCC during 24.0 months median postsurgical follow-up. FDG-PET-based total lesion glycolysis identifies MPR patients prior to surgery. A baseline AID/APOBEC-associated mutational profile and an on-treatment decrease in hypoxia RNA signature are observed in MPR patients. Our data indicate that neoadjuvant COMBO ICB is feasible and encouragingly efficacious in HNSCC.Immune checkpoint blockade has become standard care for patients with recurrent metastatic head and neck squamous cell carcinoma (HNSCC). Here the authors present the results of a non-randomized phase Ib/IIa trial, reporting safety and efficacy of neoadjuvant nivolumab monotherapy and nivolumab plus ipilimumab prior to standard-of-care surgery in patients with HNSCC. .Otorhinolaryngolog

Communication between the extracellular environment, cytoplasmic signalling cascades and the nuclear cell-cycle machinery

AbstractIn the past decade, we have gained considerable insight into the identities of various cytoplasmic signal transduction cascades and the manner in which they operate in response to changes in the extracellular environment. Moreover, we have begun to understand what the key players are in cell-cycle regulation and how they, in turn, function to promote cell division. A long-standing question, however, has been how communication between signalling routes and the cell-cycle machinery occurs. This review highlights some recent observations that provide possible links between signal transduction and the cell-cycle machinery