Changes in Breast Cancer Presentation during COVID-19: Experience in an Urban Academic Center

The COVID-19 pandemic strained healthcare systems worldwide, delaying breast cancer screening and surgery. In 2019, approximately 80% of breast cancers in the U.S. were diagnosed on screening examinations, with 76.4% of eligible Medicare patients undergoing screening at least every two years. Since the start of the pandemic, many women have been reluctant to seek elective screening mammography, even with the lifting of pandemic-related restrictions in access to routine healthcare. We describe the effect of the COVID-19 pandemic on breast cancer presentation at a tertiary academic medical center greatly impacted by the pandemic.

BTLA+CD200+ B cells dictate the divergent immune landscape and immunotherapeutic resistance in metastatic vs. primary pancreatic cancer

Response to cancer immunotherapy in primary versus metastatic disease has not been well-studied. We found primary pancreatic ductal adenocarcinoma (PDA) is responsive to diverse immunotherapies whereas liver metastases are resistant. We discovered divergent immune landscapes in each compartment. Compared to primary tumor, liver metastases in both mice and humans are infiltrated by highly anergic T cells and MHCII^loIL10⁺ macrophages that are unable to present tumor-antigen. Moreover, a distinctive population of CD24⁺CD44^-CD40^- B cells dominate liver metastases. These B cells are recruited to the metastatic milieu by Muc1^hiIL18^hi tumor cells, which are enriched >10-fold in liver metastases. Recruited B cells drive macrophage-mediated adaptive immune-tolerance via CD200 and BTLA. Depleting B cells or targeting CD200/BTLA enhanced macrophage and T-cell immunogenicity and enabled immunotherapeutic efficacy of liver metastases. Our data detail the mechanistic underpinnings for compartment-specific immunotherapy-responsiveness and suggest that primary PDA models are poor surrogates for evaluating immunity in advanced disease.

Intrahepatic microbes govern liver immunity by programming NKT cells

The gut microbiome shapes local and systemic immunity. The liver is presumed to be a protected sterile site. As such, a hepatic microbiome has not been examined. Here, we showed a liver microbiome in mice and humans that is distinct from the gut and is enriched in Proteobacteria. It undergoes dynamic alterations with age and is influenced by the environment and host physiology. Fecal microbial transfer experiments revealed that the liver microbiome is populated from the gut in a highly selective manner. Hepatic immunity is dependent on the microbiome, specifically Bacteroidetes species. Targeting Bacteroidetes with oral antibiotics reduced hepatic immune cells by ~90%, prevented APC maturation, and mitigated adaptive immunity. Mechanistically, our findings are consistent with presentation of Bacteroidetes-derived glycosphingolipids to NKT cells promoting CCL5 signaling, which drives hepatic leukocyte expansion and activation, among other possible host-microbe interactions. Collectively, we reveal a microbial - glycosphingolipid - NKT - CCL5 axis that underlies hepatic immunity.

Abstract P2-03-01: Changes in breast cancer presentation during Covid-19: Experience in an Urban Academic Center

Background: The COVID-19 pandemic strained healthcare systems worldwide, delaying breast cancer screening and surgery. In 2019, approximately 80% of breast cancers in the U.S. were diagnosed on screening examinations, with 76.4% of eligible Medicare patients undergoing screening at least every two years. Since the start of the pandemic, many women have been reluctant to seek elective screening mammography, even with the lifting of “lock-down”. We describe the effect of the COVID-19 pandemic on breast cancer presentation at an academic medical center in a city hit hard by the pandemic. Materials and Methods: The institutional IRB-approved Breast Cancer Registry Database was queried for patients enrolled during two time periods, those undergoing first surgical procedure before the start of the pandemic (4/1/2019-3/31/2020) to those the year after the pandemic started (4/1/2020-3/31/2021). Elective cancer surgery was paused for 3 weeks, ending 4/20/2020, and access to routine breast care was limited for 3 months. Variables included age, method of detection, palpability, histologic subtype and staging, neoadjuvant systemic therapy, cancer specific treatments, and radiation uptake. Results: 349 patients were in the 2019 cohort; 246 in the 2020 cohort. No differences in baseline characteristics, including age at presentation, nodal status, or operation type. Fewer cancers were detected on routine mammography post-COVID vs. pre-COVID. Increase in detection of breast cancer through self-exams in 2020 was seen compared to 2019. Palpability on presentation also increased. More patients were treated with neo-adjuvant therapy chemotherapy, and 36 of 45 (80%) eligible early-stage breast cancer patients accepted neoadjuvant hormonal therapy during the period that elective cancer surgery was on hold. Patients received radiation therapy less frequently during the pandemic. The proportion of patients diagnosed with invasive ductal cancers was higher in the 2020 cohort and the proportion of patients diagnosed with ductal carcinoma in situ (DCIS) and for invasive lobular cancers (ILC) was lower. Conclusions: Patients at an academic New York City medical center presented with more palpable and invasive breast cancers during the COVID-19 pandemic compared to the preceding year, and fewer patients with DCIS and ILC, cancers typically detected following screening mammography. While stage migration with an increase in diagnosis of late stage cancers has been described, in our population the stage shift occurred in early stage breast cancer, with decreases in DCIS and increases in Stages I-II, with the higher stages III-IV essentially unchanged. This reflects the effect of delay in our previously highly-screened population, with an average screening delay of 3 + months, and many patients missing their yearly screening altogether. While many medical interactions during COVID-19 were via telemedicine, radiation therapy requires daily office visits, and fear of exposure contributed to the lower rate of radiation. Given the increase in invasiveness and stage of breast cancers diagnosed during the COVID-19 pandemic, this study emphasizes the importance of screening for diagnosis and treatment of breast cancer, even in the face of a concurrent health crisis.

Variable2019 Population N=3492020 Population N=246P-ValueMethod of DetectionSelf-Exam19.80%26.0%0.0688Mammography67.0%60.0%Palpability31.50%39.20%0.0533Neoadjuvant Therapy8.30%10.20%0.4384Radiation Therapy65.0%54%<0.0001Age at presentation60.0460.680.6171Type of surgeryBreast Conserving Surgery69%66%<0.8508Mastectomy31%34%HistologyIDC60.70%66.7%0.5822DCIS20.9%16.7%ILC10.6%8.10%

Citation Format: Amber Azniv Guth, Brian Diskin, Freya Schnabel, Nakisa Pourkey, Deborah Axelrod, Richard Shapiro. Changes in breast cancer presentation during Covid-19: Experience in an Urban Academic Center [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-03-01.

SHP2 inhibition diminishes KRASG12C cycling and promotes tumor microenvironment remodeling

KRAS is the most frequently mutated human oncogene, and KRAS inhibition has been a longtime goal. Recently, inhibitors were developed that bind KRASG12C-GDP and react with Cys-12 (G12C-Is). Using new affinity reagents to monitor KRASG12C activation and inhibitor engagement, we found that an SHP2 inhibitor (SHP2-I) increases KRAS-GDP occupancy, enhancing G12C-I efficacy. The SHP2-I abrogated RTK feedback signaling and adaptive resistance to G12C-Is in vitro, in xenografts, and in syngeneic KRASG12C-mutant pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer (NSCLC). SHP2-I/G12C-I combination evoked favorable but tumor site-specific changes in the immune microenvironment, decreasing myeloid suppressor cells, increasing CD8+ T cells, and sensitizing tumors to PD-1 blockade. Experiments using cells expressing inhibitor-resistant SHP2 showed that SHP2 inhibition in PDAC cells is required for PDAC regression and remodeling of the immune microenvironment but revealed direct inhibitory effects on tumor angiogenesis and vascularity. Our results demonstrate that SHP2-I/G12C-I combinations confer a substantial survival benefit in PDAC and NSCLC and identify additional potential combination strategies.

Targeting Piezo1 unleashes innate immunity against cancer and infectious disease

Piezo1 is a mechanosensitive ion channel that has gained recognition for its role in regulating diverse physiological processes. However, the influence of Piezo1 in inflammatory disease, including infection and tumor immunity, is not well studied. We postulated that Piezo1 links physical forces to immune regulation in myeloid cells. We found signal transduction via Piezo1 in myeloid cells and established this channel as the primary sensor of mechanical stress in these cells. Global inhibition of Piezo1 with a peptide inhibitor was protective against both cancer and septic shock and resulted in a diminution in suppressive myeloid cells. Moreover, deletion of Piezo1 in myeloid cells protected against cancer and increased survival in polymicrobial sepsis. Mechanistically, we show that mechanical stimulation promotes Piezo1-dependent myeloid cell expansion by suppressing the retinoblastoma gene Rb1 We further show that Piezo1-mediated silencing of Rb1 is regulated via up-regulation of histone deacetylase 2. Collectively, our work uncovers Piezo1 as a targetable immune checkpoint that drives immunosuppressive myelopoiesis in cancer and infectious disease.

γδ T Cells Promote Steatohepatitis by Orchestrating Innate and Adaptive Immune Programming

BACKGROUND AND AIMS

The recruitment and activation of inflammatory cells in the liver delineates the transition from hepatic steatosis to steatohepatitis (SH).

APPROACH AND RESULTS

We found that in SH, γδT cells are recruited to the liver by C-C chemokine receptor (CCR) 2, CCR5, and nucleotide-binding oligomerization domain-containing protein 2 signaling and are skewed toward an interleukin (IL)-17A⁺ phenotype in an inducible costimulator (ICOS)/ICOS ligand-dependent manner. γδT cells exhibit a distinct Vγ4⁺ , PD1⁺ , Ly6C⁺ CD44⁺ phenotype in SH. Moreover, γδT cells up-regulate both CD1d, which is necessary for lipid-based antigens presentation, and the free fatty acid receptor, CD36. γδT cells are stimulated to express IL-17A by palmitic acid and CD1d ligation. Deletion, depletion, and targeted interruption of γδT cell recruitment protects against diet-induced SH and accelerates disease resolution.

CONCLUSIONS

We demonstrate that hepatic γδT cells exacerbate SH, independent of IL-17 expression, by mitigating conventional CD4⁺ T-cell expansion and modulating their inflammatory program by CD1d-dependent vascular endothelial growth factor expression.

CDK7 Inhibition Potentiates Genome Instability Triggering Anti-tumor Immunity in Small Cell Lung Cancer

Cyclin-dependent kinase 7 (CDK7) is a central regulator of the cell cycle and gene transcription. However, little is known about its impact on genomic instability and cancer immunity. Using a selective CDK7 inhibitor, YKL-5-124, we demonstrated that CDK7 inhibition predominately disrupts cell-cycle progression and induces DNA replication stress and genome instability in small cell lung cancer (SCLC) while simultaneously triggering immune-response signaling. These tumor-intrinsic events provoke a robust immune surveillance program elicited by T cells, which is further enhanced by the addition of immune-checkpoint blockade. Combining YKL-5-124 with anti-PD-1 offers significant survival benefit in multiple highly aggressive murine models of SCLC, providing a rationale for new combination regimens consisting of CDK7 inhibitors and immunotherapies.

Innate αβ T Cells Mediate Antitumor Immunity by Orchestrating Immunogenic Macrophage Programming

Unconventional T-lymphocyte populations are emerging as important regulators of tumor immunity. Despite this, the role of TCRαβ⁺CD4^-CD8^-NK1.1^- innate αβ T cells (iαβT) in pancreatic ductal adenocarcinoma (PDA) has not been explored. We found that iαβTs represent ∼10% of T lymphocytes infiltrating PDA in mice and humans. Intratumoral iαβTs express a distinct T-cell receptor repertoire and profoundly immunogenic phenotype compared with their peripheral counterparts and conventional lymphocytes. iαβTs comprised ∼75% of the total intratumoral IL17⁺ cells. Moreover, iαβT-cell adoptive transfer is protective in both murine models of PDA and human organotypic systems. We show that iαβT cells induce a CCR5-dependent immunogenic macrophage reprogramming, thereby enabling marked CD4⁺ and CD8⁺ T-cell expansion/activation and tumor protection. Collectively, iαβTs govern fundamental intratumoral cross-talk between innate and adaptive immune populations and are attractive therapeutic targets. SIGNIFICANCE: We found that iαβTs are a profoundly activated T-cell subset in PDA that slow tumor growth in murine and human models of disease. iαβTs induce a CCR5-dependent immunogenic tumor-associated macrophage program, T-cell activation and expansion, and should be considered as novel targets for immunotherapy.See related commentary by Banerjee et al., p. 1164.This article is highlighted in the In This Issue feature, p. 1143.

Specialized dendritic cells induce tumor-promoting IL-10+IL-17+ FoxP3neg regulatory CD4+ T cells in pancreatic carcinoma

The drivers and the specification of CD4+ T cell differentiation in the tumor microenvironment and their contributions to tumor immunity or tolerance are incompletely understood. Using models of pancreatic ductal adenocarcinoma (PDA), we show that a distinct subset of tumor-infiltrating dendritic cells (DC) promotes PDA growth by directing a unique TH-program. Specifically, CD11b+CD103- DC predominate in PDA, express high IL-23 and TGF-β, and induce FoxP3neg tumor-promoting IL-10+IL-17+IFNγ+ regulatory CD4+ T cells. The balance between this distinctive TH program and canonical FoxP3+ TREGS is unaffected by pattern recognition receptor ligation and is modulated by DC expression of retinoic acid. This TH-signature is mimicked in human PDA where it is associated with immune-tolerance and diminished patient survival. Our data suggest that CD11b+CD103- DC promote CD4+ T cell tolerance in PDA which may underscore its resistance to immunotherapy.

Targeting SYK signaling in myeloid cells protects against liver fibrosis and hepatocarcinogenesis

Liver fibrosis and fibrosis-associated hepatocarcinogenesis are driven by chronic inflammation and are leading causes of morbidity and death worldwide. SYK signaling regulates critical processes in innate and adaptive immunity, as well as parenchymal cells. We discovered high SYK expression in the parenchymal hepatocyte, hepatic stellate cell (HSC), and the inflammatory compartments in the fibrotic liver. We postulated that targeting SYK would mitigate hepatic fibrosis and oncogenic progression. We found that inhibition of SYK with the selective small molecule inhibitors Piceatannol and PRT062607 markedly protected against toxin-induced hepatic fibrosis, associated hepatocellular injury and intra-hepatic inflammation, and hepatocarcinogenesis. SYK inhibition resulted in increased intra-tumoral expression of the p16 and p53 but decreased expression of Bcl-xL and SMAD4. Further, hepatic expression of genes regulating angiogenesis, apoptosis, cell cycle regulation, and cellular senescence were affected by targeting SYK. We found that SYK inhibition mitigated both HSC trans-differentiation and acquisition of an inflammatory phenotype in T cells, B cells, and myeloid cells. However, in vivo experiments employing selective targeted deletion of SYK indicated that only SYK deletion in the myeloid compartment was sufficient to confer protection against fibrogenic progression. Targeting SYK promoted myeloid cell differentiation into hepato-protective TNFα^low CD206^hi phenotype downregulating mTOR, IL-8 signaling and oxidative phosphorylation. Collectively, these data suggest that SYK is an attractive target for experimental therapeutics in treating hepatic fibrosis and oncogenesis.

RIP1 Kinase Drives Macrophage-Mediated Adaptive Immune Tolerance in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDA) is characterized by immune tolerance and immunotherapeutic resistance. We discovered upregulation of receptor-interacting serine/threonine protein kinase 1 (RIP1) in tumor-associated macrophages (TAMs) in PDA. To study its role in oncogenic progression, we developed a selective small-molecule RIP1 inhibitor with high in vivo exposure. Targeting RIP1 reprogrammed TAMs toward an MHCII^hiTNFα⁺IFNγ⁺ immunogenic phenotype in a STAT1-dependent manner. RIP1 inhibition in TAMs resulted in cytotoxic T cell activation and T helper cell differentiation toward a mixed Th1/Th17 phenotype, leading to tumor immunity in mice and in organotypic models of human PDA. Targeting RIP1 synergized with PD1-and inducible co-stimulator-based immunotherapies. Tumor-promoting effects of RIP1 were independent of its co-association with RIP3. Collectively, our work describes RIP1 as a checkpoint kinase governing tumor immunity.

SHP2 Inhibition Prevents Adaptive Resistance to MEK Inhibitors in Multiple Cancer Models

Adaptive resistance to MEK inhibitors (MEKi) typically occurs via induction of genes for different receptor tyrosine kinases (RTK) and/or their ligands, even in tumors of the same histotype, making combination strategies challenging. SHP2 (PTPN11) is required for RAS/ERK pathway activation by most RTKs and might provide a common resistance node. We found that combining the SHP2 inhibitor SHP099 with a MEKi inhibited the proliferation of multiple cancer cell lines in vitro PTPN11 knockdown/MEKi treatment had similar effects, whereas expressing SHP099 binding-defective PTPN11 mutants conferred resistance, demonstrating that SHP099 is on-target. SHP099/trametinib was highly efficacious in xenograft and/or genetically engineered models of KRAS-mutant pancreas, lung, and ovarian cancers and in wild-type RAS-expressing triple-negative breast cancer. SHP099 inhibited activation of KRAS mutants with residual GTPase activity, impeded SOS/RAS/MEK/ERK1/2 reactivation in response to MEKi, and blocked ERK1/2-dependent transcriptional programs. We conclude that SHP099/MEKi combinations could have therapeutic utility in multiple malignancies.Significance: MEK inhibitors show limited efficacy as single agents, in part because of the rapid development of adaptive resistance. We find that SHP2/MEK inhibitor combinations prevent adaptive resistance in multiple cancer models expressing mutant and wild-type KRAS. Cancer Discov; 8(10); 1237-49. ©2018 AACR. See related commentary by Torres-Ayuso and Brognard, p. 1210 This article is highlighted in the In This Issue feature, p. 1195.

SHP2 Inhibition Prevents Adaptive Resistance to MEK Inhibitors in Multiple Cancer Models

Adaptive resistance to MEK inhibitors (MEKi) typically occurs via induction of genes for different receptor tyrosine kinases (RTK) and/or their ligands, even in tumors of the same histotype, making combination strategies challenging. SHP2 (PTPN11) is required for RAS/ERK pathway activation by most RTKs and might provide a common resistance node. We found that combining the SHP2 inhibitor SHP099 with a MEKi inhibited the proliferation of multiple cancer cell lines in vitro PTPN11 knockdown/MEKi treatment had similar effects, whereas expressing SHP099 binding-defective PTPN11 mutants conferred resistance, demonstrating that SHP099 is on-target. SHP099/trametinib was highly efficacious in xenograft and/or genetically engineered models of KRAS-mutant pancreas, lung, and ovarian cancers and in wild-type RAS-expressing triple-negative breast cancer. SHP099 inhibited activation of KRAS mutants with residual GTPase activity, impeded SOS/RAS/MEK/ERK1/2 reactivation in response to MEKi, and blocked ERK1/2-dependent transcriptional programs. We conclude that SHP099/MEKi combinations could have therapeutic utility in multiple malignancies.Significance: MEK inhibitors show limited efficacy as single agents, in part because of the rapid development of adaptive resistance. We find that SHP2/MEK inhibitor combinations prevent adaptive resistance in multiple cancer models expressing mutant and wild-type KRAS. Cancer Discov; 8(10); 1237-49. ©2018 AACR. See related commentary by Torres-Ayuso and Brognard, p. 1210 This article is highlighted in the In This Issue feature, p. 1195.

Abstract LB-338: SHP2 inhibition enhances sensitivity to MEK inhibitors in multiple resistant cancer models

Targeting tumors with kinase inhibitors induces complex adaptive programs that enable the persistence of a fraction of the original cell population, facilitating the eventual outgrowth of inhibitor-resistant tumor clones. Most tumors developing resistance to MEK inhibitors upregulate and/or activation of at least one of several different receptor tyrosine kinases (RTKs), which drive resistance. Notably, different RTKs or RTK combinations are upregulated in different cancer cells, even those from the same histotype. SHP2 (encoded by PTPN11) is required for RAS/ERK pathway activation downstream of most RTKs, suggesting that it might provide a common targetable resistance node in multiple resistant cancer cell lines. We show that the addition of a newly identified SHP2 inhibitor, SHP099, to MEK therapy enhances cell killing and impedes the emergence of drug-resistant cell populations in diverse cancer models in vitro and in vivo. These effects occurred in a wide range of malignancies, including KRAS mutant pancreas, lung cancer, triple negative breast cancer, and serous ovarian cancer cell lines, as well as in PDX and GEMM models. SHP099 effects were overcome by expressing an SHP2 mutant that loses drug binding but retain catalytic activity and regulation, demonstrating that on target effects of the inhibitor. Mechanistic studies across multiple cellular cancer models suggest that SHP2 inhibition by SHP099 prevents the compensatory RAS and ERK1/2 reactivation in response to MEK therapy and impedes the engagement of the ERK1/2 transcriptional programs (i.e., MYC, ETV1, FOSL1, etc.) and signaling outputs that characterize the drug-tolerant state. Combining full doses of MEK inhibitors and SHP099 causes significant toxicity in mice, but non-toxic, efficacious dosing regimens can be achieved. Our findings suggest that SHP099, in combination with MEK inhibition is a promising therapeutic strategy for enhancing the effectiveness of targeted therapies.

Citation Format: Carmine Fedele, Kwan Ho Tang, Hao Ran, Wei Wei, Brian Diskin, George Miller, Benjamin G. Neel. SHP2 inhibition enhances sensitivity to MEK inhibitors in multiple resistant cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-338.

The Pancreatic Cancer Microbiome Promotes Oncogenesis by Induction of Innate and Adaptive Immune Suppression

We found that the cancerous pancreas harbors a markedly more abundant microbiome compared with normal pancreas in both mice and humans, and select bacteria are differentially increased in the tumorous pancreas compared with gut. Ablation of the microbiome protects against preinvasive and invasive pancreatic ductal adenocarcinoma (PDA), whereas transfer of bacteria from PDA-bearing hosts, but not controls, reverses tumor protection. Bacterial ablation was associated with immunogenic reprogramming of the PDA tumor microenvironment, including a reduction in myeloid-derived suppressor cells and an increase in M1 macrophage differentiation, promoting TH1 differentiation of CD4⁺ T cells and CD8⁺ T-cell activation. Bacterial ablation also enabled efficacy for checkpoint-targeted immunotherapy by upregulating PD-1 expression. Mechanistically, the PDA microbiome generated a tolerogenic immune program by differentially activating select Toll-like receptors in monocytic cells. These data suggest that endogenous microbiota promote the crippling immune-suppression characteristic of PDA and that the microbiome has potential as a therapeutic target in the modulation of disease progression.Significance: We found that a distinct and abundant microbiome drives suppressive monocytic cellular differentiation in pancreatic cancer via selective Toll-like receptor ligation leading to T-cell anergy. Targeting the microbiome protects against oncogenesis, reverses intratumoral immune tolerance, and enables efficacy for checkpoint-based immunotherapy. These data have implications for understanding immune suppression in pancreatic cancer and its reversal in the clinic. Cancer Discov; 8(4); 403-16. ©2018 AACR.See related commentary by Riquelme et al., p. 386This article is highlighted in the In This Issue feature, p. 371.

NLRP3 signaling drives macrophage-induced adaptive immune suppression in pancreatic carcinoma

The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDA) is characterized by immune tolerance, which enables disease to progress unabated by adaptive immunity. However, the drivers of this tolerogenic program are incompletely defined. In this study, we found that NLRP3 promotes expansion of immune-suppressive macrophages in PDA. NLRP3 signaling in macrophages drives the differentiation of CD4+ T cells into tumor-promoting T helper type 2 cell (Th2 cell), Th17 cell, and regulatory T cell populations while suppressing Th1 cell polarization and cytotoxic CD8+ T cell activation. The suppressive effects of NLRP3 signaling were IL-10 dependent. Pharmacological inhibition or deletion of NLRP3, ASC (apoptosis-associated speck-like protein containing a CARD complex), or caspase-1 protected against PDA and was associated with immunogenic reprogramming of innate and adaptive immunity within the TME. Similarly, transfer of PDA-entrained macrophages or T cells from NLRP3-/- hosts was protective. These data suggest that targeting NLRP3 holds the promise for the immunotherapy of PDA.

Dectin 1 activation on macrophages by galectin 9 promotes pancreatic carcinoma and peritumoral immune tolerance

The progression of pancreatic oncogenesis requires immune-suppressive inflammation in cooperation with oncogenic mutations. However, the drivers of intratumoral immune tolerance are uncertain. Dectin 1 is an innate immune receptor crucial for anti-fungal immunity, but its role in sterile inflammation and oncogenesis has not been well defined. Furthermore, non-pathogen-derived ligands for dectin 1 have not been characterized. We found that dectin 1 is highly expressed on macrophages in pancreatic ductal adenocarcinoma (PDA). Dectin 1 ligation accelerated the progression of PDA in mice, whereas deletion of Clec7a-the gene encoding dectin 1-or blockade of dectin 1 downstream signaling was protective. We found that dectin 1 can ligate the lectin galectin 9 in mouse and human PDA, which results in tolerogenic macrophage programming and adaptive immune suppression. Upon disruption of the dectin 1-galectin 9 axis, CD4⁺ and CD8⁺ T cells, which are dispensable for PDA progression in hosts with an intact signaling axis, become reprogrammed into indispensable mediators of anti-tumor immunity. These data suggest that targeting dectin 1 signaling is an attractive strategy for developing an immunotherapy for PDA.

Incidence of patellar clunk syndrome in fixed versus high-flex mobile bearing posterior-stabilized total knee arthroplasty

The geometry of the intercondylar box plays a significant role in the development of patellar clunk syndrome. We reviewed the incidence of patella clunk at mid-to-long-term follow-up of a rotating high-flex versus fixed bearing posterior stabilized TKA design. 188-mobile and 223-fixed bearing TKAs were reviewed for complications, incidence of patellar clunk, treatment, recurrence rates, range of motion, and patient satisfaction. Patellar clunk developed in 22 knees in the mobile (11.7%) and in 4 (1.8%) in the fixed bearing group (P<0.001). 23 out of 26 cases resolved with a single arthroscopic treatment and 2 resolved with a second procedure. The mean postoperative range of motion was 122.4°. All but one patient reported overall satisfaction with the index procedure. In contrast with other recent studies we found a significant incidence of patellar clunk in high-flex mobile bearings. Despite the high rate of patellar clunk syndrome, overall patients did well and were satisfied with their outcomes.

Isolation and subunit structure of polycytidylate-dependent RNA polymerase of encephalomyocarditis virus

A polycytidylate-dependent RNA polymerase of encephalomyocarditis virus was isolated from infected BHK 21 cells. The enzyme was associated with a smooth-membrane fraction, from which it was extracted by a mixture of sodium dodecyl sulfate, Triton X-100, and dithiothreitol, and further purified by chromatography on a Dowex-1 column and by glycerol gradient sedimentation. Analysis of a 6S glycerol gradient peak of RNA polymerase activity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of five polypeptides, of molecular weights 72,000, 65,000, 57,000, 45,000, and 35,000. The molecular weights of four of the polypeptides (72,000, 65,000, 45,000, and 35,000) are almost identical to the reported molecular weights of the four subunits of Qbeta replicase.