Towards a mechanistic understanding of patient response to neoadjuvant SBRT with anti-PDL1 in human HPV-unrelated locally advanced HNSCC: Phase I/Ib trial results (Part 2)
Project description:Five-year survival for HPV-unrelated head and neck squamous cell carcinomas (HNSCC) remains below 50%. We assessed the safety of administering combination hypofractionated stereotactic body radiation therapy (SBRT) with anti-PDL-1 neoadjuvantly followed by adjuvant anti-PDL-1 with standard of care therapy (n=21) (NCT03635164). The primary endpoint of the study was safety, which was met. Secondary endpoints included radiographic, pathologic, and objective response, locoregional control (LRC), progression-free survival (PFS), and overall survival (OS). Among evaluable patients at early median follow-up of 16 months (448 days, or 64 weeks), OS was 80.1% with 95% C.I. (62.0%, 100.0%), LRC and PFS were 75.8% with 95% C.I. (57.5%, 99.8%), and major pathological response (MPR) or complete response (CR) was 75% with 95% exact C.I. (51.6%, 100%). Circulating CD8/Treg ratio, CD4 effector memory T cells, and TCR repertoire at time of surgery emerged as biologic correlates of response to therapy. Using high-dimensional multi-omics and spatial data as well as biological correlatives pre- and post-treatment, three major changes were noted in responders within the tumor microenvironment (TME) (and within the blood) post-treatment: 1) an increase in effector T cells; 2) a decrease in immunosuppressive cells; and 3) an increase in antigen presentation. Non-responders appeared to fail due to a lack of one of these three identified steps needed for priming and maintaining activation of T cells. Multiple correlates for response, along with subsets of non-responders that may benefit from additional or alternative immunotherapies, were identified. This treatment is being tested in an ongoing phase II trial with a similar design, where we hope to confirm and expand on our understanding of the mechanisms underlying resistance to therapy.
Project description:Towards a mechanistic understanding of patient response to neoadjuvant SBRT with anti-PDL1 in human HPV-unrelated locally advanced HNSCC: Phase I/Ib trial results
Project description:Five year survival rates for pancreatic cancer remain low, around 11%. We assessed differential gene expression between SBRT responders and non-responders as well as expression pre and post SBRT. Samples were obtained from the University of Colorado biorepository. All patients had borderline resectable pancreatic cancer, treated with neoadjuvant chemotherapy followed by restaging, and treatment with 30–33.6 Gy SBRT to pancreatic tumors, followed by pancreaticoduodenectomy and adjuvant chemotherapy. We observed increases in PDL1, PD1, CD25, and a decrease in CD122 expression following RT. Furthermore, we found that responders to SBRT exhibit decrased CD25 expression with increased CD122 and CD132 expression compared to non-responders. Using GSEA of responders vs. non-responders, we found responders to SBRT exhibit enrichment of inflammatory response, IFN signaling, and IL2/STAT5 signaling.
Project description:CGL (Congenital generalized lipodystrophy) is a genetic disorder characterized by near complete loss of adipose tissue along with increased ectopic fat storage in other organs including liver and muscle. Of the four CGL types, BSCL2 (Berardinelli-Seip Congenital lipodystrophy type 2), resulting from mutations in the BSCL2/seipin gene, exhibits the most severe lipodystrophic phenotype with loss of both metabolic and mechanical adipose depots. The majority of Seipin mutations cause C-terminal truncations, along with a handful of point mutations. Seipin localizes to the ER and is composed of a conserved region including a luminal loop and two transmembrane domains, plus cytosolic N- and C-termini. Animal models deficient in seipin recapitulate the human lipodystrophic phenotype. Cells isolated from seipin knockout mouse models also exhibit impaired adipogenesis. Mechanistically, seipin appears to function as a scaffolding protein to bring together interacting partners essential for lipid metabolism and LD (lipid droplet) formation during adipocyte development. Moreover, cell line and genetic studies indicate that seipin functions in a cell-autonomous manner. Here we will provide a brief overview of the genetic association of the CGLs, and focus on the current understanding of differential contributions of distinct seipin domains to lipid storage and adipogenesis. We will also discuss the roles of seipin-interacting partners, including lipin 1 and 14-3-3?, in mediating seipin-dependent regulation of cellular pathways such as actin cytoskeletal remodelling.
Project description:Schlafen 11 (SLFN11) is an interferon-inducible antiviral restriction factor with tRNA endoribonuclease and DNA binding functions. It is recruited to stalled replication forks in response to replication stress and inhibits replication of certain viruses such as the human immunodeficiency virus 1 (HIV-1) by modulating the tRNA pool. SLFN11 has been identified as a predictive biomarker in cancer, as its expression correlates with a beneficial response to DNA damage inducing anticancer drugs. However, the mechanism and interdependence of these two functions are largely unknown. Here, we present cryo-electron microscopy (cryo-EM) structures of human SLFN11 in its dimeric apoenzyme state, bound to tRNA and in complex with single-strand DNA. Full-length SLFN11 neither hydrolyses nor binds ATP and the helicase domain appears in an autoinhibited state. Together with biochemical and structure guided mutagenesis studies, our data give detailed insights into the mechanism of endoribonuclease activity as well as suggestions on how SLFN11 may block stressed replication forks.
Project description:Vα24-invariant natural killer T cells (NKTs) have antitumor properties that can be enhanced by transgenic expression of tumor-specific receptors. Here, we report the results of the first-in-human clinical evaluation of autologous NKTs co-expressing a GD2-specific chimeric antigen receptor with interleukin (IL)15 (GD2-CAR.15) in 12 children with neuroblastoma (NB) treated on four dose levels (NCT03294954). Objectives included assessing safety, antitumor activity, and immune response. No dose-limiting toxicities occurred, and one patient had grade 2 cytokine release syndrome resolved by tocilizumab. The overall response rate was 25% (3/12) and disease control rate was 58% (7/12) including four patients with stable disease, two partial responses, and one complete response. CD62L+ NKT frequency in infused products correlated with CAR-NKT expansion in patients and was higher in responders than non-responders (71% vs 35.3%, p=0.002). Singe-cell RNA sequencing analysis identified B cell translocation gene 1 (BTG1) as one of the top upregulated genes in GD2-CAR.15-NKTs after in vitro serial tumor challenge. Genetic gain- and loss-of-function experiments revealed that BTG1 is a key driver of hyporesponsiveness in exhausted NKT and T cells. Crucially, NKTs co-expressing GD2-CAR.15 and BTG1-specific shRNA eradicated metastatic NB in mice. These results indicate that CAR-NKTs are safe, produce objective responses in NB patients, and that targeting BTG1 can enhance their therapeutic potency.
Project description:Minerals stabilize organic carbon (OC) in sediments, thereby directly affecting global climate at multiple scales, but how they do it is far from understood. Here we show that manganese oxide (Mn oxide) in a water treatment works filter bed traps dissolved OC as coatings build up in layers around clean sand grains at 3%w/wC. Using spectroscopic and thermogravimetric methods, we identify two main OC fractions. One is thermally refractory (>550 °C) and the other is thermally more labile (<550 °C). We postulate that the thermal stability of the trapped OC is due to carboxylate groups within it bonding to Mn oxide surfaces coupled with physical entrapment within the layers. We identify a significant difference in the nature of the surface-bound OC and bulk OC . We speculate that polymerization reactions may be occurring at depth within the layers. We also propose that these processes must be considered in future studies of OC in natural systems.
Project description:To identify the most appropriate format for results dissemination to maximise understanding of trial results. Qualitative. Of the original 58 4-T trial centres, 34 agreed to take part in this ancillary research. All participants from these centres were eligible. All 343 participants were sent questionnaires. The low response rate meant that we were unable to make any firm conclusions about the patients' preferred method of dissemination; however, we were able to comment on the level of understanding demonstrated by the trial participants. All 40 (12%) returned questionnaires were received from 15 centres. We received no questionnaires from over half of the centres. The questionnaires which were returned demonstrated broad satisfaction with the results letter, general enthusiasm for the trial and a variable level of understanding of the results; however, there was a high proportion of responders who were not clear on why the research was undertaken or what the results meant. The low response rate may be related to delays during the trial set-up process suggesting that interest in a study quickly wanes for both patients and centres. From this we deduce that rapid dissemination of results is needed if it is to have any impact at all. The responders are likely to reflect a biased cohort who were both enthusiastic about the research and who had a good experience during their 3 years in the 4-T trial. It is perhaps not surprising therefore that the overview is positive. That this population was still not fully informed about the purpose of the research would seem to confirm a low level of understanding among the general public which we suggest should be addressed during the consent process.