Genomic Biomarkers to Predict Response to Atezolizumab Plus Bevacizumab Immunotherapy in Hepatocellular Carcinoma: Insights from the IMbrave150 Trial.

Introduction: Combination immunotherapy, exemplified by atezolizumab plus bevacizumab, has become the standard of care for inoperable hepatocellular carcinoma (HCC). However, the lack of predictive biomarkers and limited understanding of response mechanisms remain a challenge. Methods: Using data from the IMbrave150plus cohort, we applied an immune signature score (ISS) predictor to stratify HCC patients treated with atezolizumab plus bevacizumab or with sorafenib alone into potential high and low response groups. By applying multiple statistical approaches including a Bayesian covariate prediction algorithm, we refined the signature to 10 key genes (ISS10) for clinical use while maintaining similar predictive power to the full model. We further validated ISS10 in an independent HCC cohort treated with nivolumab plus ipilimumab. Results: The study identified a significant association between the ISS and treatment response. Among patients classified as high responders, those treated with the atezolizumab plus bevacizumab combination exhibited improved overall and progression-free survival as well as better objective response rate compared to those treated with sorafenib. We also observed a significant correlation between ISS10 and response to nivolumab plus ipilimumab treatment. Analysis of immune cell subpopulations revealed distinct characteristics associated with ISS subtypes. In particular, the ISS10 high subtype displayed a more favorable immune environment with higher proportions of anti-tumor macrophages and activated T-cells, potentially explaining its better response. Conclusions: Our study suggests that ISS and ISS10 are promising predictive biomarkers for enhanced therapeutic outcomes in HCC patients undergoing combination immunotherapy. These markers are crucial for refining patient stratification and personalized treatment approaches to advance the effectiveness of standard-of-care regimens.

STING agonist 8803 reprograms the immune microenvironment and increases survival in preclinical models of glioblastoma.

STING agonists can reprogram the tumor microenvironment to induce immunological clearance within the central nervous system. Using multiplexed sequential immunofluorescence (SeqIF) and the Ivy Glioblastoma Atlas, STING expression was found in myeloid populations and in the perivascular space. The STING agonist 8803 increased median survival in multiple preclinical models of glioblastoma, including QPP8, an immune checkpoint blockade-resistant model, where 100% of mice were cured. Ex vivo flow cytometry profiling during the therapeutic window demonstrated increases in myeloid tumor trafficking and activation, alongside enhancement of CD8+ T cell and NK effector responses. Treatment with 8803 reprogrammed microglia to express costimulatory CD80/CD86 and iNOS, while decreasing immunosuppressive CD206 and arginase. In humanized mice, where tumor cell STING is epigenetically silenced, 8803 therapeutic activity was maintained, further attesting to myeloid dependency and reprogramming. Although the combination with a STAT3 inhibitor did not further enhance STING agonist activity, the addition of anti-PD-1 antibodies to 8803 treatment enhanced survival in an immune checkpoint blockade-responsive glioma model. In summary, 8803 as a monotherapy demonstrates marked in vivo therapeutic activity, meriting consideration for clinical translation.

Bilateral first metatarsophalangeal joint arthrodesis: An investigation of functional, surgical and radiological outcomes.

BACKGROUND: First metatarsophalangeal joint (MTPJ) arthrodesis is a commonly utilised procedure. In this study, the authors aim to explore functional outcomes of patients undergoing nonsynchronous bilateral first MTPJ arthrodesis under the care of a single surgeon using a compression screw/locking plate construct. METHODS: This is a prospectively collected, retrospectively analysed case series of fifty five patients who underwent bilateral nonsynchronous first MTPJ arthrodesis. Clinical and radiological outcomes were assessed preoperatively and at a minimum of two years postoperatively. Clinical outcomes were assessed using the Foot and Ankle Outcome Score (FAOS), the Self-Reported Foot and Ankle Score (SEFAS) and the Sports Questionnaire version 1 (SQ). Postoperative radiographs were used to assess evidence of union and compare both hallux valgus and intermetatarsal angles. Removal of hardware, revision surgery and correction of deformities were also recorded. RESULTS: Fifty five patients were included in the study. There was statistically significant improvements in all five facets of the FAOS (p value < 0.05). The mean postoperative SEFAS was 45.1. In total, patients participated in thirteen different sporting activities. This represented 92 patient specific activities preoperatively and 104 postoperatively. The most common activities were walking, cycling and swimming. Overall, 94.5% (N = 52) of the cohort were satisfied with their return to sport while 98.2% (N = 54) would recommend bilateral first MTPJ arthrodesis. Mean reductions in hallux valgus angles and intermetatarsal angles were noted at 18.87 and 4.69 degrees respectively. There was one non-union in the cohort which required revision surgery. One patient required removal of hardware. CONCLUSIONS: Bilateral first MTPJ arthrodesis is a safe and effective surgical option for patients with bilateral first MTPJ pathology. It has a high union rate, low complication rate and significantly improves clinical outcomes and allows patients reliably return to physical activities.

Palliative care in a Graduate Entry Medical Curriculum: exploring students' attitudes on the importance of receiving teaching in palliative care.

BACKGROUND: As people live longer with life-limiting illnesses, there is greater need for skills and knowledge in palliative care (PC). Medical students should acquire the knowledge, attitudes, and confidence during training for future decision-making. However, most graduates across Europe feel unprepared to provide PC. To develop PC training for medical students, we must gain perspective on their understanding of PC and their learning needs. OBJECTIVES: The aim was to investigate graduate entry medical students' views on the importance of education in PC and how well PC topics were covered within their curriculum. The objective was to highlight areas that could be reviewed for future PC curricula. METHODS: In this prospective quantitative study, penultimate and final-year students were recruited from a graduate entry medical school. Ethical approval was granted. Students completed an online questionnaire. RESULTS: From 281 recruited students, 82 responded. Ninety-five percent of respondents felt everyone should have a PC rotation. The aspects of education perceived to be most important were knowledge of symptom control, communication, ethical issues, self-care, and grief. The only aspect considered well covered within the curriculum was ethical issues. Ninety-six percent of penultimate and 75% of final years wanted more teaching in PC. CONCLUSION: Graduate entry medical students view PC as a vital subject within their medical school training. The study highlights challenges in providing education and sufficient placement in PC to correlate with the respondents' perceived needs. The findings contribute to the growing literature surrounding the importance of PC education within the medical school curriculum.

Identification of Nonfunctional Alternatively Spliced Isoforms of STING in Human Acute Myeloid Leukemia.

Lack of robust activation of Stimulator of Interferon Genes (STING) pathway and subsequent induction of type I IFN responses is considered a barrier to antitumor immunity in acute myeloid leukemia (AML). Using common human AML cell lines as in vitro tools to evaluate the efficacy of novel STING agonists, we found most AML lines to be poor producers of IFNs upon exposure to extremely potent agonists, suggesting cell-intrinsic suppression of STING signaling may occur. We observed unexpected patterns of response that did not correlate with levels of STING pathway components or of known enzymes associated with resistance. To identify a genetic basis for these observations, we cloned and sequenced STING from the cDNA of human AML cell lines and found both frequent mutations and deviations from normal RNA splicing. We identified two novel spliced isoforms of STING in these lines and validated their expression in primary human AML samples. When transduced into reporter cells, these novel STING isoforms exhibited complete insensitivity to agonist stimulation. These observations identify alternative splicing as a mechanism of STING pathway suppression and suggest that most AML silences the STING pathway through direct modification rather than through engagement of external inhibitory factors. SIGNIFICANCE: We find that AML acquires resistance to innate immune activation via the STING pathway through aberrant splicing of the STING transcript including two novel forms described herein that act as dominant negatives. These data broaden understanding of how cancers evolve STING resistance, and suggest that the AML tumor microenvironment, not the cancer cell, should be the target of therapeutic interventions to activate STING.

A biogeographical appraisal of the threatened South East Africa Montane Archipelago ecoregion.

Recent biological surveys of ancient inselbergs in southern Malawi and northern Mozambique have led to the discovery and description of many species new to science, and overlapping centres of endemism across multiple taxa. Combining these endemic taxa with data on geology and climate, we propose the 'South East Africa Montane Archipelago' (SEAMA) as a distinct ecoregion of global biological importance. The ecoregion encompasses 30 granitic inselbergs reaching > 1000 m above sea level, hosting the largest (Mt Mabu) and smallest (Mt Lico) mid-elevation rainforests in southern Africa, as well as biologically unique montane grasslands. Endemic taxa include 127 plants, 45 vertebrates (amphibians, reptiles, birds, mammals) and 45 invertebrate species (butterflies, freshwater crabs), and two endemic genera of plants and reptiles. Existing dated phylogenies of endemic animal lineages suggests this endemism arose from divergence events coinciding with repeated isolation of these mountains from the pan-African forests, together with the mountains' great age and relative climatic stability. Since 2000, the SEAMA has lost 18% of its primary humid forest cover (up to 43% in some sites)-one of the highest deforestation rates in Africa. Urgently rectifying this situation, while addressing the resource needs of local communities, is a global priority for biodiversity conservation.

A comparison of available guidelines for the detection of cauda equina syndrome and assessing the need for further clinical guidance in Ireland.

The cauda equina syndrome (CES) is a rare but critical disorder, which can result in devastating motor weakness and sensory deficit, alongside often irreversible bladder, bowel and sexual dysfunction. In addition to the clinical burden of disease, this syndrome results in a disproportionately high medicolegal strain due to missed or delayed diagnoses. Despite being an emergency diagnosis, often necessitating urgent surgical decompression to treat, we believe there is a lack of clarity for clinicians in the current literature, with no published Irish guideline concerning screening or detection. The current study aims to identify and analyse appropriate guidelines in relation to CES screening which are available to clinicians in Ireland. The study design included a comprehensive literature review and comparison of existing guidelines. The review identified 13 sources of appropriate guidance for clinicians working in Ireland. These resources included textbooks, websites and guidelines developed in the UK. No Irish guidelines or advice were available on CES screening/treatment at the time of review. This review demonstrated the lack of consensus and guidance for clinicians in Ireland on how to effectively screen for CES, judge who requires further imaging and investigations and how to rule out the condition. A national consensus on thorough screening and prompt investigation for CES is necessary, and the formulation of new CES guidelines would be a welcome addition to what is available to clinicians currently.

Outcomes following tibiotalocalcaneal arthrodesis using a solid posterior offset intramedullary nail in 44 patients with a minimum 30-month follow-up.

BACKGROUND: Tibiotalocalcaneal arthrodesis is frequently performed by foot and ankle surgeons in the management of complex ankle and hindfoot pathology. In this study, the authors describe the clinical and radiological outcomes of tibiotalocalcaneal arthrodesis using a solid posterior offset hindfoot arthrodesis nail. METHODS: Forty-four consecutive patients underwent tibiotalocalcaneal arthrodesis by a single surgeon operating in two centers. Clinical and radiological outcomes were assessed preoperatively and at 6-month, 12-month and final follow-up (mean 47 months). Clinical outcomes were assessed with VAS, AOFAS and MOXFQ scores. Serial radiographs were used to assess union at each follow-up visit. RESULTS: Forty-four patients attended 12-month and final follow-up (mean 47 months). A total of 44 (100%) ankle joints and 44 (100%) subtalar joints were completely united at 12-month follow-up. The VAS score improved significantly from a mean of 6.5 preoperatively to a mean of 0.98 at final follow-up (P = <0.0001). AOFAS score improved significantly from a mean of 36.4 preoperatively to a mean of 73 at final follow-up (P = <0.0001). MOXFQ score improved significantly from a mean of 44.5 preoperatively to a mean of 12.7 at final follow-up (P = <0.0001). The mean change in frontal plane alignment was 5.7 degrees (P = 0.005). A total of 6 patients (13.6%) had an adverse event during the course of the study. CONCLUSIONS: Tibiotalocalcaneal arthrodesis with a solid posterior offset hindfoot arthrodesis nail is a safe and effective surgical option for patients with severe ankle and hindfoot pathology. It has a high union rate, low complication rate and significantly improves clinical outcomes.

Differing impacts of the COVID-19 pandemic on farmers and intermediaries: insights into the Ecuadorian cocoa value chain.

The COVID-19 pandemic generated diverse impacts and responses in agricultural value chains worldwide. Cocoa is a key crop for Ecuadorian exports, and the analysis of effects the pandemic had on value chain actors contributes to the understanding of their individual capacities to coping with a major shock. The purpose of this study was to assess the number and severity of impacts and responses implemented by two links in the cocoa value chain to the pandemic, based on a survey of 158 cocoa farmers and 52 cocoa intermediaries from the main cocoa-producing provinces of the northern coast of Ecuador in 2021. Surveyed farmers and part of the intermediaries form part of the sustainability program of a large Swiss chocolate manufacturer. The impacts and responses reported were grouped into seven resources according to the Activity System Approach. Then, a comparison between groups was applied using the Wilcoxon rank sum test for nonparametric data, determining the most severe impacts and effective resilience responses among the actors. The results reveal that farmers and intermediaries were similarly affected by the pandemic, reporting 21 and 16 negative impacts, respectively. Farmers experienced a higher number and severity of impacts on financial and social resources, while intermediaries on human and material resources. The strongest impact was the loss of sales, reported by 65% of farmers and 58% of intermediaries. Farmers implemented more social responses that they judged highly effective, while intermediaries implemented more human responses that they judged highly effective. Public policy should enhance the social resources of farmers by strengthening their associativity and the capacities of their members, as mechanisms to mitigate their vulnerability to future health and climate crises. The financial resources of both actors should be protected through public credit and agricultural insurance.

Hypoxia-activated prodrug and antiangiogenic therapies cooperatively treat pancreatic cancer but elicit immunosuppressive G-MDSC infiltration.

We previously showed that ablation of tumor hypoxia can sensitize tumors to immune checkpoint blockade (ICB). Here, we used a Kras+/G12D TP53+/R172H Pdx1-Cre-derived (KPC-derived) model of pancreatic adenocarcinoma to examine the tumor response and adaptive resistance mechanisms involved in response to 2 established methods of hypoxia-reducing therapy: the hypoxia-activated prodrug TH-302 and vascular endothelial growth factor receptor 2 (VEGFR-2) blockade. The combination of both modalities normalized tumor vasculature, increased DNA damage and cell death, and delayed tumor growth. In contrast with prior cancer models, the combination did not alleviate overall tissue hypoxia or sensitize these KPC tumors to ICB therapy despite qualitative improvements to the CD8+ T cell response. Bulk tumor RNA sequencing, flow cytometry, and adoptive myeloid cell transfer suggested that treated tumor cells increased their capacity to recruit granulocytic myeloid-derived suppressor cells (G-MDSCs) through CCL9 secretion. Blockade of the CCL9/CCR1 axis could limit G-MDSC migration, and depletion of Ly6G-positive cells could sensitize tumors to the combination of TH-302, anti-VEGFR-2, and ICB. Together, these data suggest that pancreatic tumors modulate G-MDSC migration as an adaptive response to vascular normalization and that these immunosuppressive myeloid cells act in a setting of persistent hypoxia to maintain adaptive immune resistance.

PD-1 blockade in combination with dasatinib potentiates induction of anti-acute lymphocytic leukemia immunity.

Immunotherapy, in the form of hematopoietic stem cell transplantation (HSCT), has been part of the standard of care in the treatment of acute leukemia for over 40 years. Trials evaluating novel immunotherapeutic approaches, such as targeting the programmed death-1 (PD-1) pathway, have unfortunately not yielded comparable results to those seen in solid tumors. Major histocompatibility complex (MHC) proteins are cell surface proteins essential for the adaptive immune system to recognize self versus non-self. MHC typing is used to determine donor compatibility when evaluating patients for HSCT. Recently, loss of MHC class II (MHC II) was shown to be a mechanism of immune escape in patients with acute myeloid leukemia after HSCT. Here we report that treatment with the tyrosine kinase inhibitor, dasatinib, and an anti-PD-1 antibody in preclinical models of Philadelphia chromosome positive B-cell acute lymphoblastic leukemia is highly active. The dasatinib and anti-PD-1 combination reduces tumor burden, is efficacious, and extends survival. Mechanistically, we found that treatment with dasatinib significantly increased MHC II expression on the surface of antigen-presenting cells (APC) in a tumor microenvironment-independent fashion and caused influx of APC cells into the leukemic bone marrow. Finally, the induction of MHC II may potentiate immune memory by impairing leukemic engraftment in mice previously cured with dasatinib, after re-inoculation of leukemia cells. In summary, our data suggests that anti-PD-1 therapy may enhance the killing ability of dasatinib via dasatinib driven APC growth and expansion and upregulation of MHC II expression, leading to antileukemic immune rewiring.

Testing the hierarchy of predictability in grassland restoration across a gradient of environmental severity.

Ecological restoration is critical for recovering degraded ecosystems but is challenged by variable success and low predictability. Understanding which outcomes are more predictable and less variable following restoration can improve restoration effectiveness. Recent theory asserts that the predictability of outcomes would follow an order from most to least predictable from coarse to fine community properties (physical structure > taxonomic diversity > functional composition > taxonomic composition) and that predictability would increase with more severe environmental conditions constraining species establishment. We tested this "hierarchy of predictability" hypothesis by synthesizing outcomes along an aridity gradient with 11 grassland restoration projects across the United States. We used 1829 vegetation monitoring plots from 227 restoration treatments, spread across 52 sites. We fit generalized linear mixed-effects models to predict six indicators of restoration outcomes as a function of restoration characteristics (i.e., seed mixes, disturbance, management actions, time since restoration) and used variance explained by models and model residuals as proxies for restoration predictability. We did not find consistent support for our hypotheses. Physical structure was among the most predictable outcomes when the response variable was relative abundance of grasses, but unpredictable for total canopy cover. Similarly, one dimension of taxonomic composition related to species identities was unpredictable, but another dimension of taxonomic composition indicating whether exotic or native species dominated the community was highly predictable. Taxonomic diversity (i.e., species richness) and functional composition (i.e., mean trait values) were intermittently predictable. Predictability also did not increase consistently with aridity. The dimension of taxonomic composition related to the identity of species in restored communities was more predictable (i.e., smaller residuals) in more arid sites, but functional composition was less predictable (i.e., larger residuals), and other outcomes showed no significant trend. Restoration outcomes were most predictable when they related to variation in dominant species, while those responding to rare species were harder to predict, indicating a potential role of scale in restoration predictability. Overall, our results highlight additional factors that might influence restoration predictability and add support to the importance of continuous monitoring and active management beyond one-time seed addition for successful grassland restoration in the United States.

Galectin-3 Cooperates with CD47 to Suppress Phagocytosis and T-cell Immunity in Gastric Cancer Peritoneal Metastases.

The peritoneal cavity is a common site of gastric adenocarcinoma (GAC) metastasis. Peritoneal carcinomatosis (PC) is resistant to current therapies and confers poor prognosis, highlighting the need to identify new therapeutic targets. CD47 conveys a "don't eat me" signal to myeloid cells upon binding its receptor signal regulatory protein alpha (SIRPα), which helps tumor cells circumvent macrophage phagocytosis and evade innate immune responses. Previous studies demonstrated that the blockade of CD47 alone results in limited clinical benefits, suggesting that other target(s) might need to be inhibited simultaneously with CD47 to elicit a strong antitumor response. Here, we found that CD47 was highly expressed on malignant PC cells, and elevated CD47 was associated with poor prognosis. Galectin-3 (Gal3) expression correlated with CD47 expression, and coexpression of Gal3 and CD47 was significantly associated with diffuse type, poor differentiation, and tumor relapse. Depletion of Gal3 reduced expression of CD47 through inhibition of c-Myc binding to the CD47 promoter. Furthermore, injection of Gal3-deficient tumor cells into either wild-type and Lgals3-/- mice led to a reduction in M2 macrophages and increased T-cell responses compared with Gal3 wild-type tumor cells, indicating that tumor cell-derived Gal3 plays a more important role in GAC progression and phagocytosis than host-derived Gal3. Dual blockade of Gal3 and CD47 collaboratively suppressed tumor growth, increased phagocytosis, repolarized macrophages, and boosted T-cell immune responses. These data uncovered that Gal3 functions together with CD47 to suppress phagocytosis and orchestrate immunosuppression in GAC with PC, which supports exploring a novel combination therapy targeting Gal3 and CD47. SIGNIFICANCE: Dual inhibition of CD47 and Gal3 enhances tumor cell phagocytosis and reprograms macrophages to overcome the immunosuppressive microenvironment and suppress tumor growth in peritoneal metastasis of gastric adenocarcinoma.

Molecular mechanisms of snoRNA-IL-15 crosstalk in adipocyte lipolysis and NK cell rejuvenation.

Obesity, in which the functional importance of small nucleolar RNAs (snoRNAs) remains elusive, correlates with risk for many cancer types. Here, we identify that the serum copies of adipocyte-expressed SNORD46 correlate with body mass index (BMI), and serum SNORD46 antagonizes interleukin-15 (IL-15) signaling. Mechanically, SNORD46 binds IL-15 via G11, and G11A (a mutation that significantly enhances binding affinity) knockin drives obesity in mice. Functionally, SNORD46 blocks IL-15-induced, FER kinase-dependent phosphorylation of platelet glycoprotein 4 (CD36) and monoglyceride lipase (MGLL) in adipocytes, leading to inhibited lipolysis and browning. In natural killer (NK) cells, SNORD46 suppresses the IL-15-dependent autophagy, leading to reduced viability of obese NK. SNORD46 power inhibitors exhibit anti-obesity effects, concurring with improved viability of obese NK and anti-tumor immunity of CAR-NK cell therapy. Hence, our findings demonstrate the functional importance of snoRNAs in obesity and the utility of snoRNA power inhibitors for antagonizing obesity-associated immune resistance.

Pan-cancer T cell atlas links a cellular stress response state to immunotherapy resistance.

Tumor-infiltrating T cells offer a promising avenue for cancer treatment, yet their states remain to be fully characterized. Here we present a single-cell atlas of T cells from 308,048 transcriptomes across 16 cancer types, uncovering previously undescribed T cell states and heterogeneous subpopulations of follicular helper, regulatory and proliferative T cells. We identified a unique stress response state, TSTR, characterized by heat shock gene expression. TSTR cells are detectable in situ in the tumor microenvironment across various cancer types, mostly within lymphocyte aggregates or potential tertiary lymphoid structures in tumor beds or surrounding tumor edges. T cell states/compositions correlated with genomic, pathological and clinical features in 375 patients from 23 cohorts, including 171 patients who received immune checkpoint blockade therapy. We also found significantly upregulated heat shock gene expression in intratumoral CD4/CD8+ cells following immune checkpoint blockade treatment, particularly in nonresponsive tumors, suggesting a potential role of TSTR cells in immunotherapy resistance. Our well-annotated T cell reference maps, web portal and automatic alignment/annotation tool could provide valuable resources for T cell therapy optimization and biomarker discovery.

Tumor-associated nonmyelinating Schwann cell-expressed PVT1 promotes pancreatic cancer kynurenine pathway and tumor immune exclusion.

One of the major obstacles to treating pancreatic ductal adenocarcinoma (PDAC) is its immunoresistant microenvironment. The functional importance and molecular mechanisms of Schwann cells in PDAC remains largely elusive. We characterized the gene signature of tumor-associated nonmyelinating Schwann cells (TASc) in PDAC and indicated that the abundance of TASc was correlated with immune suppressive tumor microenvironment and the unfavorable outcome of patients with PDAC. Depletion of pancreatic-specific TASc promoted the tumorigenesis of PDAC tumors. TASc-expressed long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) was triggered by the tumor cell-produced interleukin-6. Mechanistically, PVT1 modulated RAF proto-oncogene serine/threonine protein kinase-mediated phosphorylation of tryptophan 2,3-dioxygenase in TASc, facilitating its enzymatic activities in catalysis of tryptophan to kynurenine. Depletion of TASc-expressed PVT1 suppressed PDAC tumor growth. Furthermore, depletion of TASc using a small-molecule inhibitor effectively sensitized PDAC to immunotherapy, signifying the important roles of TASc in PDAC immune resistance.

IL6 Mediates Suppression of T- and NK-cell Function in EMT-associated TKI-resistant EGFR-mutant NSCLC.

PURPOSE: Patients with advanced non-small cell lung cancer (NSCLC) harboring activating EGFR mutations are initially responsive to tyrosine kinase inhibitors (TKI). However, therapeutic resistance eventually emerges, often via secondary EGFR mutations or EGFR-independent mechanisms such as epithelial-to-mesenchymal transition. Treatment options after EGFR-TKI resistance are limited as anti-PD-1/PD-L1 inhibitors typically display minimal benefit. Given that IL6 is associated with worse outcomes in patients with NSCLC, we investigate whether IL6 in part contributes to this immunosuppressed phenotype. EXPERIMENTAL DESIGN: We utilized a syngeneic genetically engineered mouse model (GEMM) of EGFR-mutant NSCLC to investigate the effects of IL6 on the tumor microenvironment and the combined efficacy of IL6 inhibition and anti-PD-1 therapy. Corresponding in vitro studies used EGFR-mutant human cell lines and clinical specimens. RESULTS: We identified that EGFR-mutant tumors which have oncogene-independent acquired resistance to EGFR-TKIs were more mesenchymal and had markedly enhanced IL6 secretion. In EGFR-mutant GEMMs, IL6 depletion enhanced activation of infiltrating natural killer (NK)- and T-cell subpopulations and decreased immunosuppressive regulatory T and Th17 cell populations. Inhibition of IL6 increased NK- and T cell-mediated killing of human osimertinib-resistant EGFR-mutant NSCLC tumor cells in cell culture. IL6 blockade sensitized EGFR-mutant GEMM tumors to PD-1 inhibitors through an increase in tumor-infiltrating IFNγ+ CD8+ T cells. CONCLUSIONS: These data indicate that IL6 is upregulated in EGFR-mutant NSCLC tumors with acquired EGFR-TKI resistance and suppressed T- and NK-cell function. IL6 blockade enhanced antitumor immunity and efficacy of anti-PD-1 therapy warranting future clinical combinatorial investigations.

Novel murine glioblastoma models that reflect the immunotherapy resistance profile of a human disease.

BACKGROUND: The lack of murine glioblastoma models that mimic the immunobiology of human disease has impeded basic and translational immunology research. We, therefore, developed murine glioblastoma stem cell lines derived from Nestin-CreERT2QkL/L; Trp53L/L; PtenL/L (QPP) mice driven by clinically relevant genetic mutations common in human glioblastoma. This study aims to determine the immune sensitivities of these QPP lines in immunocompetent hosts and their underlying mechanisms. METHODS: The differential responsiveness of QPP lines was assessed in the brain and flank in untreated, anti-PD-1, or anti-CTLA-4 treated mice. The impact of genomic landscape on the responsiveness of each tumor was measured through whole exome sequencing. The immune microenvironments of sensitive (QPP7) versus resistant (QPP8) lines were compared in the brain using flow cytometry. Drivers of flank sensitivity versus brain resistance were also measured for QPP8. RESULTS: QPP lines are syngeneic to C57BL/6J mice and demonstrate varied sensitivities to T cell immune checkpoint blockade ranging from curative responses to complete resistance. Infiltrating tumor immune analysis of QPP8 reveals improved T cell fitness and augmented effector-to-suppressor ratios when implanted subcutaneously (sensitive), which are absent on implantation in the brain (resistant). Upregulation of PD-L1 across the myeloid stroma acts to establish this state of immune privilege in the brain. In contrast, QPP7 responds to checkpoint immunotherapy even in the brain likely resulting from its elevated neoantigen burden. CONCLUSIONS: These syngeneic QPP models of glioblastoma demonstrate clinically relevant profiles of immunotherapeutic sensitivity and potential utility for both mechanistic discovery and evaluation of immune therapies.