Low-dose adjuvant epigenetic therapy (AET) reduced metastasis and promoted survival in mouse models.

LGR5^– cells seed colorectal cancer metastases and produce stemlike LGR5⁺ outgrowth-promoting cells.

Tumor-derived retinoic acid promotes monocyte differentiation into immunosuppressive macrophages.

T cell–expressed PD-L1 exerts tolerogenic effects on tumor immunity in pancreatic cancer.

Symmetric division of stem cells positive for gastrin receptor CCK2R is linked to gastric cancer.

In a draft guidance, the FDA urges researchers to take steps to increase enrollment of adults age 65 and older in clinical trials of investigational of cancer drugs. Noting that a drug's risk–benefit profile can vary significantly across age groups, the FDA recommends including older adults in early-phase studies and modifying trial designs and recruitment strategies to make it easier for them to participate.

Genomic analysis of a patient's tumor is the cornerstone of precision oncology, but it does not address whether metastases should be treated differently. Here we tested whether comparative single-cell RNA sequencing (scRNA-seq) of a primary small intestinal neuroendocrine tumor to a matched liver metastasis could guide the treatment of a patient's metastatic disease. Following surgery, the patient was put on maintenance treatment with a somatostatin analog. However, the scRNA-seq analysis revealed that the neuroendocrine epithelial cells in the liver metastasis were less differentiated and expressed relatively little SSTR2, the predominant somatostatin receptor. There were also differences in the tumor microenvironments. RNA expression of vascular endothelial growth factors was higher in the primary tumor cells, reflected by an increased number of endothelial cells. Interestingly, vascular expression of the major VEGF receptors was considerably higher in the liver metastasis, indicating that the metastatic vasculature may be primed for expansion and susceptible to treatment with angiogenesis inhibitors. The patient eventually progressed on Sandostatin, and although consideration was given to adding an angiogenesis inhibitor to her regimen, her disease progression involved non-liver metastases that had not been characterized. Although in this specific case comparative scRNA-seq did not alter treatment, its potential to help guide therapy of metastatic disease was clearly demonstrated.

Wilms tumor (WT) is the most common renal malignancy of childhood and accounts for 6% of all childhood malignancies. With current therapies, the 5-yr overall survival (OS) for children with unilateral favorable histology WT is greater than 85%. The prognosis is worse, however, for the roughly 15% of patients who relapse, with only 50%–80% OS reported in those with recurrence. Herein, we describe the extended and detailed clinical course of a rare case of a child with recurrent, pulmonary metastatic, favorable histology WT harboring a BRAF V600E mutation. The BRAF V600E mutation, commonly found in melanoma and other cancers, and previously undescribed in WT, has recently been reported by our group in a subset of epithelial-predominant WT. This patient, who was included in that series, presented with unilateral, stage 1, favorable histology WT and was treated with standard chemotherapy. Following the completion of therapy, the patient relapsed with pulmonary metastatic disease, that then again recurred despite an initial response to salvage chemotherapy and radiation. Next-generation sequencing (NGS) on the metastatic pulmonary nodule revealed a BRAF V600E mutation. After weighing the therapeutic options, a novel approach with dual BRAF/MEK inhibitor combination therapy was initiated. Complete radiographic response was observed following 4 months of therapy with dabrafenib and trametinib. At 12 months following the start of BRAF/MEK combination treatment, the patient continues with a complete response and has experienced minimal treatment-related side effects. This represents the first case, to our knowledge, of effective treatment with BRAF/MEK molecularly targeted therapy in a pediatric Wilms tumor patient.

A chambered heart is common to all vertebrates, but reptiles show unparalleled variation in ventricular septation, ranging from almost absent in tuataras to full in crocodilians. Because mammals and birds evolved independently from reptile lineages, studies on reptile development may yield insight into the evolution and development of the full ventricular septum. Compared with reptiles, mammals and birds have evolved several other adaptations, including compact chamber walls and a specialized conduction system. These adaptations appear to have evolved from precursor structures that can be studied in present-day reptiles. The increase in the number of studies on reptile heart development has been greatly facilitated by sequencing of several genomes and the availability of good staging systems. Here, we place reptiles in their phylogenetic context with a focus on features that are primitive when compared with the homologous features of mammals. Further, an outline of major developmental events is given, and variation between reptile species is discussed.

Understanding how coronary blood vessels form and regenerate during development and progression of cardiac diseases will shed light on the development of new treatment options targeting coronary artery diseases. Recent studies with the state-of-the-art technologies have identified novel origins of, as well as new, cellular and molecular mechanisms underlying the formation of coronary vessels in the postnatal heart, including collateral artery formation, endocardial-to-endothelial differentiation and mesenchymal-to-endothelial transition. These new mechanisms of coronary vessel formation and regeneration open up new possibilities targeting neovascularization for promoting cardiac repair and regeneration. Here, we highlight some recent studies on cellular mechanisms of coronary vessel formation, and discuss the potential impact and significance of the findings on basic research and clinical application for treating ischemic heart disease.

Inflammasomes assemble in the cytosol of myeloid and epithelial cells on sensing of cellular stress and pathogen-associated molecular patterns and serve as scaffolds for recruitment and activation of inflammatory caspases. Inflammasomes play beneficial roles in host and immune responses against diverse pathogens but may also promote inflammatory tissue damage if uncontrolled. Gasdermin D (GSDMD) is a recently identified substrate of murine caspase-1 and caspase-11, and human caspases-1, -4, and -5 that mediates a regulated lytic cell death mode termed pyroptosis. Recent studies have identified pyroptosis as a critical inflammasome effector mechanism that controls inflammasome-dependent cytokine secretion and contributes to antimicrobial defense and inflammasome-mediated autoinflammatory diseases. Here, we review recent developments on inflammasome-associated effector functions with an emphasis on the emerging roles of gasdermin pores and pyroptosis.

Maintenance of the proteome, ensuring the proper locations, proper conformations, appropriate concentrations, etc., is essential to preserve the health of an organism in the face of environmental insults, infectious diseases, and the challenges associated with aging. Maintaining the proteome is even more difficult in the background of inherited mutations that render a given protein and others handled by the same proteostasis machinery misfolding prone and/or aggregation prone. Maintenance of the proteome or maintaining proteostasis requires the orchestration of protein synthesis, folding, trafficking, and degradation by way of highly conserved, interacting, and competitive proteostasis pathways. Each subcellular compartment has a unique proteostasis network compromising common and specialized proteostasis maintenance pathways. Stress-responsive signaling pathways detect the misfolding and/or aggregation of proteins in specific subcellular compartments using stress sensors and respond by generating an active transcription factor. Subsequent transcriptional programs up-regulate proteostasis network capacity (i.e., ability to fold and degrade proteins in that compartment). Stress-responsive signaling pathways can also be linked by way of signaling cascades to nontranscriptional means to reestablish proteostasis (e.g., by translational attenuation). Proteostasis is also strongly influenced by the inherent kinetics and thermodynamics of the folding, misfolding, and aggregation of individual proteins, and these sequence-based attributes in combination with proteostasis network capacity together influence proteostasis. In this review, we will focus on the growing body of evidence that proteostasis deficits leading to human pathology can be reversed by pharmacologic adaptation of proteostasis network capacity through stress-responsive signaling pathway activation. The power of this approach will be exemplified by focusing on the ATF6 arm of the unfolded protein response stress responsive-signaling pathway that regulates proteostasis network capacity of the secretory pathway.

Quality Improvement Success Stories are published by the American Diabetes Association in collaboration with the American College of Physicians, Inc. (ACP), and the National Diabetes Education Program. This series is intended to highlight best practices and strategies from programs and clinics that have successfully improved the quality of care for people with diabetes or related conditions. Each article in the series is reviewed and follows a standard format developed by the editors of Clinical Diabetes. The following article describes an initiative of the Cleveland Clinic’s internal medicine residents to improve diabetes care and outcomes within an underserved patient population at an East Cleveland, OH, health center.

Adolescents with type 1 diabetes face self-management challenges that make it difficult for them to achieve good glycemic control. In our population of adolescents with poorly controlled type 1 diabetes, the use of continuous glucose monitoring (CGM) improved patients’ glycemic time in range (TIR) and identified hypoglycemia more frequently than with intermittent self-monitoring of blood glucose throughout a 4-week interval. However, the adolescents were unable to synthesize this information to problem-solve or reduce the frequency of hypoglycemic events. Setting SMART (specific, measurable, achievable, relevant, and time-bound) diabetes management goals and providing intensive diabetes education and support could increase adolescents’ TIR and prevent hypoglycemia.

The T1D Exchange established a learning platform by evaluating the current state of care and engaging 10 diabetes clinics in collaborative quality improvement (QI) activities. Participating clinics are sharing data and best practices to improve care delivery for people with type 1 diabetes. This article describes the design and initial implementation of this platform, known as the T1D Exchange Quality Improvement Collaborative. This effort has laid a foundation for learning from variation in type 1 diabetes care delivery via QI methodology and has demonstrated success in improving processes through iterative testing cycles and transparent sharing of data.

Background:

Lipid traits have been inconsistently linked to risk of non-Hodgkin lymphoma (NHL). We examined the association of genetically predicted lipid traits with risk of diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), and marginal zone lymphoma (MZL) using Mendelian randomization (MR) analysis.

Background:

The impact of light-intensity physical activity (LPA) in preventing cancer mortality has been questioned. To address this concern, the present meta-analysis aimed to quantify the association between objectively-measured LPA and risk of cancer mortality.

Background:

Sex steroid hormones and sex hormone–binding globulin (SHBG) have been implicated in the etiology of invasive breast cancer, but their associations with risk of the precursor lesion, ductal carcinoma in situ (DCIS) of the breast, remain unclear.

Background:

Percent density (PD) is a strong risk factor for breast cancer that is potentially modifiable by lifestyle factors. PD is a composite of the dense (DA) and nondense (NDA) areas of a mammogram, representing predominantly fibroglandular or fatty tissues, respectively. Alcohol and tobacco use have been associated with increased breast cancer risk. However, their effects on mammographic density (MD) phenotypes are poorly understood.

Background:

Research on the relationship of meat, fish, and egg consumption and mortality among prostate cancer survivors is limited.

Background:

Despite smoking being a well-established risk factor for pancreatic cancer, there is a need to further characterize pancreatic cancer risk according to lifespan smoking patterns and other smoking features, such as tobacco type. Our aim was to deeply investigate them within a large European case–control study.

Background:

Energy balance–related factors, such as body mass index (BMI), diet, and physical activity, may influence colorectal cancer etiology through interconnected metabolic pathways, but their combined influence is less clear.

Background:

Visceral adipose tissue (VAT) may play a greater role than subcutaneous fat in increasing cancer risk but is poorly estimated in epidemiologic studies.

Background:

The associations of abdominal skeletal muscle mass index (SMI), visceral and subcutaneous adipose tissue (VAT and SAT, respectively), and mortality among patients with stage I–III colorectal cancer may differ for men and women, but only few studies stratified their data into men and women. We investigated associations of abdominal SMI, VAT, and SAT with overall mortality among men and among women with stage I–III colorectal cancer.

Background:

Limited treatment options are available for oral mucositis, a common, debilitating complication of cancer therapy. We examined the association between daily delivery time of radiotherapy and the severity of oral mucositis in patients with head and neck cancer.

Background:

The recent expansion of treatment options in acute myeloid leukemia (AML) has necessitated a greater understanding of patient preferences for treatment benefits, about which little is known.

Background:

We assessed the ability to supplement existing epidemiologic/etiologic studies with data on treatment and clinical outcomes by linking to publicly available cancer registry and administrative databases.

Background:

The success of multisite collaborative research relies on effective data collection, harmonization, and aggregation strategies. Data Coordination Centers (DCC) serve to facilitate the implementation of these strategies. The utility of a DCC can be particularly relevant for research on rare diseases where collaboration from multiple sites to amass large aggregate datasets is essential. However, approaches to building a DCC have been scarcely documented.

Background:

Relatives of patients with bladder cancer have been shown to be at increased risk for kidney, lung, thyroid, and cervical cancer after correcting for smoking-related behaviors that may concentrate in some families. We demonstrate a novel approach to simultaneously assess risks for multiple cancers to identify distinct multicancer configurations (multiple different cancer types that cluster in relatives) surrounding patients with familial bladder cancer.

Background:

Asian Americans are at higher risk for noncardia gastric cancers (NCGC) relative to non-Hispanic Whites (NHW). Asian Americans are genetically, linguistically, and culturally heterogeneous, yet have mostly been treated as a single population in prior studies. This aggregation may obscure important subgroup-specific cancer patterns.

Background:

New technologies are being developed for early detection of multiple types of cancer simultaneously. To quantify the potential benefit, we estimated reductions in absolute cancer–related deaths that could occur if cancers diagnosed after metastasis (stage IV) were instead diagnosed at earlier stages.

The 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Score was developed to establish a simple, standardized scoring system for researchers to quantify adherence to the 2018 WCRF/AICR Cancer Prevention Recommendations and assess its impact on cancer risk and other health-related outcomes. The aim of this commentary is to clarify potential points of ambiguity in its application, focusing on aspects related to specific subscore components (physical activity, fast foods, alcohol, and sugar-sweetened drinks), how to address different data needs due to varied data collection instruments, and future exploratory score approaches. Overall, we encourage researchers to utilize the standardized score to enhance comparability across populations and countries. Researchers who may adapt or augment the 2018 WCRF/AICR Score are strongly encouraged to provide detailed descriptions of their methods to promote transparency and reproducibility.

Escherichia coli DNA Pol I can carry out three enzymatic reactions: It possesses 5' -> 3' DNA polymerase activity and 3' -> 5' and 5' -> 3' exonuclease activity. Pol I can be cleaved by mild treatment with subtilisin into two fragments; the larger fragment is known as the Klenow fragment. The Klenow fragment retains the polymerizing activity and the 3' -> 5' exonuclease of the holo-enzyme but lacks its powerful 5' -> 3' exonuclease activity. These enzymes and their applications in molecular cloning are introduced here.

The Klenow fragment, which retains the template-dependent deoxynucleotide polymerizing activity and the 3' -> 5' exonuclease of the holo-enzyme but lacks its powerful 5' -> 3' exonuclease activity, is used to fill recessed 3' termini of dsDNA. In this protocol, fragments suitable as templates for the end-filling reaction are produced by digestion of DNA with an appropriate restriction enzyme. The Klenow enzyme is then used to catalyze the attachment of dNTPs to the recessed 3'-hydroxyl groups.

High-throughput sequencing methods have created exciting opportunities to explore the regulatory landscape of the entire genome. Here we introduce methods to characterize the genomic locations of bound proteins, open chromatin, and sites of DNA–DNA contact in Xenopus embryos. These methods include chromatin immunoprecipitation followed by sequencing (ChIP-seq), a combination of DNase I digestion and sequencing (DNase-seq), the assay for transposase-accessible chromatin and sequencing (ATAC-seq), and the use of proximity-based DNA ligation followed by sequencing (Hi-C).

Adeno-associated virus (AAV) recombinants are currently the vector of choice for many gene therapy applications. As experimental therapies progress to clinical trials, the need to characterize recombinant adeno-associated viruses (rAAVs) accurately and reproducibly increases. Accurate determination of rAAV infectious titer is important for determining the activity of each vector lot and for ensuring lot-to-lot consistency. The following protocol developed in our laboratory uses a 96-well TCID₅₀ format and quantitative polymerase chain reaction (qPCR) detection for the determination of rAAV infectious titer.

This protocol is used to determine the concentration of DNase-resistant vector genomes (i.e., packaged in the capsid) in purified recombinant adeno-associated virus (rAAV) preparations. The protocol begins with treatment of the vector stock with DNase I to eliminate unencapsidated AAV DNA or contaminating plasmid DNA. This is followed by a heat treatment to heat-inactivate DNase I, to disrupt the viral capsid, and to release the packaged vector genomes for quantification by real-time polymerase chain reaction (PCR) using a set of standards (linearized plasmid used for vector production) containing known copy numbers. To accomplish high-throughput titration, the primer and probe sets used in real-time PCR are usually designed to target common elements present in most rAAV genomes, such as promoters and poly(A) signals. This strategy significantly reduces the number of PCRs, controls, and turnaround time. Several important controls should be included in the assay as follows: The first two controls should have a known copy number of the rAAV genome plasmid treated or not treated with DNase I. This control tests the effectiveness of DNase treatment. To control for potential cross-contamination between samples during the preparation process, a blank control containing nuclease-free water only should be processed and tested in parallel. A validation vector sample with a known titer should be included in every assay to monitor interassay variability. Finally, for the PCR run, a no-template control (NTC) is included to indicate cross-contamination during PCR setup.

Tobacco smoking is the primary risk factor for lung cancer, driven by the addictive nature of nicotine and the indisputable carcinogenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) as well as other compounds. The integration of lung cancer chemoprevention with smoking cessation is one potential approach to reduce this risk and mitigate lung cancer mortality. Experimental data from our group suggest that kava, commonly consumed in the South Pacific Islands as a beverage to promote relaxation, may reduce lung cancer risk by enhancing NNK detoxification and reducing NNK-derived DNA damage. Building upon these observations, we conducted a pilot clinical trial to evaluate the effects of a 7-day course of kava on NNK metabolism in active smokers. The primary objective was to compare urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL plus its glucuronides, major metabolites of NNK) before and after kava administration as an indicator of NNK detoxification. Secondary objectives included determining kava's safety, its effects on DNA damage, tobacco use, and cortisol (a biomarker of stress). Kava increased urinary excretion of total NNAL and reduced urinary 3-methyladenine in participants, suggestive of its ability to reduce the carcinogenicity of NNK. Kava also reduced urinary total nicotine equivalents, indicative of its potential to facilitate tobacco cessation. Plasma cortisol and urinary total cortisol equivalents were reduced upon kava use, which may contribute to reductions in tobacco use. These results demonstrate the potential of kava intake to reduce lung cancer risk among smokers.

Mammographic breast density is a strong risk factor for breast cancer. We comprehensively investigated the associations of body mass index (BMI) change from ages 10, 18, and 30 to age at mammogram with mammographic breast density in postmenopausal women. We used multivariable linear regression models, adjusted for confounders, to investigate the associations of BMI change with volumetric percent density, dense volume, and nondense volume, assessed using Volpara in 367 women. At the time of mammogram, the mean age was 57.9 years. Compared with women who had a BMI gain of 0.1–5 kg/m² from age 10, women who had a BMI gain of 5.1–10 kg/m² had a 24.4% decrease [95% confidence interval (CI), 6.0%–39.2%] in volumetric percent density; women who had a BMI gain of 10.1–15 kg/m² had a 46.1% decrease (95% CI, 33.0%–56.7%) in volumetric percent density; and women who had a BMI gain of >15 kg/m² had a 56.5% decrease (95% CI, 46.0%–65.0%) in volumetric percent density. Similar, but slightly attenuated associations were observed for BMI gain from ages 18 and 30 to age at mammogram and volumetric percent density. BMI gain over the life course was positively associated with nondense volume, but not dense volume. We observed strong associations between BMI change over the life course and mammographic breast density. The inverse associations between early-life adiposity change and volumetric percent density suggest that childhood adiposity may confer long-term protection against postmenopausal breast cancer via its effect of mammographic breast density.

While smoking is inextricably linked to oral/head and neck cancer (HNSCC), only a small fraction of smokers develop HNSCC. Thus, we have sought to identify other factors, which may influence the development of HNSCC in smokers including microbiology. To determine microbial associations with HNSCC among tobacco users, we characterized oral microbiome composition in smokers with and without HNSCC. 16S rRNA MiSeq sequencing was used to examine the oral mucosa microbiome of 27 smokers with (cases) and 24 without HNSCC (controls). In addition, we correlated previously reported levels of DNA damage with the microbiome data. Smokers with HNSCC showed lower microbiome richness compared with controls (q = 0.012). Beta-diversity analyses, assessed as UniFrac (weighted and unweighted) and Bray–Curtis distances, showed significant differences in oral mucosal microbiome signatures between cases and controls (r² = 0.03; P = 0.03) and higher interindividual microbiome heterogeneity in the former (q ≤ 0.01). Higher relative abundance of Stenotrophomonas and Comamonadaceae and predicted bacterial pathways mainly involved in xenobiotic and amine degradation were found in cases compared with controls. The latter, in contrast, exhibited higher abundance of common oral commensals and predicted sugar degradation pathways. Finally, levels of DNA damage in the oral cavity were correlated with the microbiome profiles above. Oral microbiome traits differ in smokers with and without HNSCC, potentially informing the risk of eventual HNSCC and shedding light into possible microbially mediated mechanisms of disease. These findings present data that may be useful in screening efforts for HNSCC among smokers who are unable to quit.

Women of Latin American origin in the United States are more likely to be diagnosed with advanced breast cancer and have a higher risk of mortality than non-Hispanic White women. Studies in U.S. Latinas and Latin American women have reported a high incidence of HER2 positive (+) tumors; however, the factors contributing to this observation are unknown. Genome-wide genotype data for 1,312 patients from the Peruvian Genetics and Genomics of Breast Cancer Study (PEGEN-BC) were used to estimate genetic ancestry. We tested the association between HER2 status and genetic ancestry using logistic and multinomial logistic regression models. Findings were replicated in 616 samples from Mexico and Colombia. Average Indigenous American (IA) ancestry differed by subtype. In multivariate models, the odds of having an HER2+ tumor increased by a factor of 1.20 with every 10% increase in IA ancestry proportion (95% CI, 1.07–1.35; P = 0.001). The association between HER2 status and IA ancestry was independently replicated in samples from Mexico and Colombia. Results suggest that the high prevalence of HER2+ tumors in Latinas could be due in part to the presence of population-specific genetic variant(s) affecting HER2 expression in breast cancer.Significance:The positive association between Indigenous American genetic ancestry and HER2+ breast cancer suggests that the high incidence of HER2+ subtypes in Latinas might be due to population and subtype-specific genetic risk variants.

Although ample evidence indicates that immune cell homeostasis is an important prognostic outcome determinant in patients with cancer, few studies have examined whether it also determines cancer risk among initially healthy individuals. We performed a case–cohort study including incident cases of breast (n = 207), colorectal (n = 111), lung (n = 70), and prostate (n = 201) cancer as well as a subcohort (n = 465) within the European Prospective Investigation into Cancer and Nutrition-Heidelberg cohort. Relative counts of neutrophils, monocytes, and lymphocyte sublineages were measured by qRT-PCR. HRs and 95% confidence intervals were used to measure the associations between relative counts of immune cell and cancer risks. When relative counts of immune cell types were taken individually, a significant positive association was observed between relative counts of FOXP3+ regulatory T cells (Tregs) and lung cancer risk, and significant inverse associations were observed between relative CD8+ counts and risks of lung and breast cancer (overall and ER+ subtype). Multivariable models with mutual adjustments across immune markers showed further significant positive associations between higher relative FOXP3+ T-cell counts and increased risks of colorectal and breast cancer (overall and ER− subtype). No associations were found between immune cell composition and prostate cancer risk. These results affirm the relevance of elevated FOXP3+ Tregs and lower levels of cytotoxic (CD8+) T cells as risk factors for tumor development.Significance:This epidemiologic study supports a role for both regulatory and cytotoxic T cells in determining cancer risk among healthy individuals.See related commentary by Song and Tworoger, p. 1801

Recurrent hotspot (p.Gly17Val) mutations in RHOA encoding a small GTPase, together with loss-of-function mutations in TET2 encoding an epigenetic regulator, are genetic hallmarks of angioimmunoblastic T-cell lymphoma (AITL). Mice expressing the p.Gly17Val RHOA mutant on a Tet2-null background succumbed to AITL-like T-cell lymphomas due to deregulated T-cell receptor (TCR) signaling. Using these mice to investigate therapeutics for AITL, we found that dasatinib, a multikinase inhibitor prolonged their survival through inhibition of hyperactivated TCR signaling. A phase I clinical trial study of dasatinib monotherapy in 5 patients with relapsed/refractory AITL was performed. Dasatinib was started at a dose of 100 mg/body once a day and continued until days 10–78 (median day 58). All the evaluable patients achieved partial responses. Our findings suggest that AITL is highly dependent on TCR signaling and that dasatinib could be a promising candidate drug for AITL treatment.Significance:Deregulated T-cell receptor signaling is a critical molecular event in angioimmunoblastic T-cell lymphoma and can be targeted with dasatinib.

Skeletal muscle wasting is a devastating consequence of cancer that contributes to increased complications and poor survival, but is not well understood at the molecular level. Herein, we investigated the role of Myocilin (Myoc), a skeletal muscle hypertrophy-promoting protein that we showed is downregulated in multiple mouse models of cancer cachexia. Loss of Myoc alone was sufficient to induce phenotypes identified in mouse models of cancer cachexia, including muscle fiber atrophy, sarcolemmal fragility, and impaired muscle regeneration. By 18 months of age, mice deficient in Myoc showed significant skeletal muscle remodeling, characterized by increased fat and collagen deposition compared with wild-type mice, thus also supporting Myoc as a regulator of muscle quality. In cancer cachexia models, maintaining skeletal muscle expression of Myoc significantly attenuated muscle loss, while mice lacking Myoc showed enhanced muscle wasting. Furthermore, we identified the myocyte enhancer factor 2 C (MEF2C) transcription factor as a key upstream activator of Myoc whose gain of function significantly deterred cancer-induced muscle wasting and dysfunction in a preclinical model of pancreatic ductal adenocarcinoma (PDAC). Finally, compared with noncancer control patients, MYOC was significantly reduced in skeletal muscle of patients with PDAC defined as cachectic and correlated with MEF2c. These data therefore identify disruptions in MEF2c-dependent transcription of Myoc as a novel mechanism of cancer-associated muscle wasting that is similarly disrupted in muscle of patients with cachectic cancer.Significance:This work identifies a novel transcriptional mechanism that mediates skeletal muscle wasting in murine models of cancer cachexia that is disrupted in skeletal muscle of patients with cancer exhibiting cachexia.

Determining mechanisms of resistance to αPD-1/PD-L1 immune-checkpoint immunotherapy is key to developing new treatment strategies. Cancer-associated fibroblasts (CAF) have many tumor-promoting functions and promote immune evasion through multiple mechanisms, but as yet, no CAF-specific inhibitors are clinically available. Here we generated CAF-rich murine tumor models (TC1, MC38, and 4T1) to investigate how CAFs influence the immune microenvironment and affect response to different immunotherapy modalities [anticancer vaccination, TC1 (HPV E7 DNA vaccine), αPD-1, and MC38] and found that CAFs broadly suppressed response by specifically excluding CD8+ T cells from tumors (not CD4+ T cells or macrophages); CD8+ T-cell exclusion was similarly present in CAF-rich human tumors. RNA sequencing of CD8+ T cells from CAF-rich murine tumors and immunochemistry analysis of human tumors identified significant upregulation of CTLA-4 in the absence of other exhaustion markers; inhibiting CTLA-4 with a nondepleting antibody overcame the CD8+ T-cell exclusion effect without affecting Tregs. We then examined the potential for CAF targeting, focusing on the ROS-producing enzyme NOX4, which is upregulated by CAF in many human cancers, and compared this with TGFβ1 inhibition, a key regulator of the CAF phenotype. siRNA knockdown or pharmacologic inhibition [GKT137831 (Setanaxib)] of NOX4 “normalized” CAF to a quiescent phenotype and promoted intratumoral CD8+ T-cell infiltration, overcoming the exclusion effect; TGFβ1 inhibition could prevent, but not reverse, CAF differentiation. Finally, NOX4 inhibition restored immunotherapy response in CAF-rich tumors. These findings demonstrate that CAF-mediated immunotherapy resistance can be effectively overcome through NOX4 inhibition and could improve outcome in a broad range of cancers.Significance:NOX4 is critical for maintaining the immune-suppressive CAF phenotype in tumors. Pharmacologic inhibition of NOX4 potentiates immunotherapy by overcoming CAF-mediated CD8+ T-cell exclusion.Graphical Abstract:http://cancerres.aacrjournals.org/content/canres/80/9/1846/F1.large.jpg.See related commentary by Hayward, p. 1799

T-cell immunoglobulin and mucin domain–containing molecule 3 (TIM-3), a potential immunotherapeutic target for cancer, has been shown to display diverse characteristics in a context-dependent manner. Thus, it would be useful to delineate the precise functional features of TIM-3 in a given situation. Here, we report that glial TIM-3 shows distinctive properties in the brain tumor microenvironment. TIM-3 was expressed on both growing tumor cells and their surrounding cells including glia and T cells in an orthotopic mouse glioma model. The expression pattern of TIM-3 was distinct from those of other immune checkpoint molecules in tumor-exposed and tumor-infiltrating glia. Comparison of cells from tumor-bearing and contralateral hemispheres of a glioma model showed that TIM-3 expression was lower in tumor-infiltrating CD11b+CD45mid glial cells but higher in tumor-infiltrating CD8+ T cells. In TIM-3 mutant mice with intracellular signaling defects and Cre-inducible TIM-3 mice, TIM-3 affected the expression of several immune-associated molecules including iNOS and PD-L1 in primary glia-exposed conditioned media (CM) from brain tumors. Further, TIM-3 was cross-regulated by TLR2, but not by TLR4, in brain tumor CM- or Pam3CSK4-exposed glia. In addition, following exposure to tumor CM, IFNγ production was lower in T cells cocultured with TIM-3–defective glia than with normal glia. Collectively, these findings suggest that glial TIM-3 actively and distinctively responds to brain tumor, and plays specific intracellular and intercellular immunoregulatory roles that might be different from TIM-3 on T cells in the brain tumor microenvironment.Significance:TIM-3 is typically thought of as a T-cell checkpoint receptor. This study demonstrates a role for TIM-3 in mediating myeloid cell responses in glioblastoma.