Reversing immunosuppression in the tumor microenvironment of fibrolamellar carcinoma via PD-1 and IL-10 blockade

Fibrolamellar carcinoma (FLC) is a rare liver tumor driven by the DNAJ-PKAc fusion protein that affects healthy young patients. Little is known about the immune response to FLC, limiting rational design of immunotherapy. Multiplex immunohistochemistry and gene expression profiling were performed to characterize the FLC tumor immune microenvironment and adjacent non-tumor liver (NTL). Flow cytometry and T cell receptor (TCR) sequencing were performed to determine the phenotype of tumor-infiltrating immune cells and the extent of T cell clonal expansion. Fresh human FLC tumor slice cultures (TSCs) were treated with antibodies blocking programmed cell death protein-1 (PD-1) and interleukin-10 (IL-10), with results measured by cleaved caspase-3 immunohistochemistry. Immune cells were concentrated in fibrous stromal bands, rather than in the carcinoma cell compartment. In FLC, T cells demonstrated decreased activation and regulatory T cells in FLC had more frequent expression of PD-1 and CTLA-4 than in NTL. Furthermore, T cells had relatively low levels of clonal expansion despite high TCR conservation across individuals. Combination PD-1 and IL-10 blockade signficantly increased cell death in human FLC TSCs. Immunosuppresion in the FLC tumor microenvironment is characterized by T cell exclusion and exhaustion, which may be reversible with combination immunotherapy.

Production of an interleukin-10 blocking antibody by genetically engineered macrophages increases cancer cell death in human gastrointestinal tumor slice cultures

Although it can promote effector T-cell function, the summative effect of interleukin-10 (IL-10) in the tumor microenvironment (TME) appears to be suppressive; therefore, blocking this critical regulatory cytokine has therapeutic potential to enhance antitumor immune function. As macrophages efficiently localize to the TME, we hypothesized that they could be used as a delivery vehicle for drugs designed to block this pathway. To test our hypothesis, we created and evaluated genetically engineered macrophages (GEMs) that produce an IL-10-blocking antibody (αIL-10). Healthy donor human peripheral blood mononuclear cells were differentiated and transduced with a novel lentivirus (LV) encoding BT-063, a humanized αIL-10 antibody. The efficacy of αIL-10 GEMs was assessed in human gastrointestinal tumor slice culture models developed from resected specimens of pancreatic ductal adenocarcinoma primary tumors and colorectal cancer liver metastases. LV transduction led to sustained production of BT-063 by αIL-10 GEMs for at least 21 days. Transduction did not alter GEM phenotype as evaluated by flow cytometry, but αIL-10 GEMs produced measurable quantities of BT-063 in the TME that was associated with an ~5-fold higher rate of tumor cell apoptosis than control.

Leveraging immune resistance archetypes in solid cancer to inform next-generation anticancer therapies

Anticancer immunotherapies, such as immune checkpoint inhibitors, bispecific antibodies, and chimeric antigen receptor T cells, have improved outcomes for patients with a variety of malignancies. However, most patients either do not initially respond or do not exhibit durable responses due to primary or adaptive/acquired immune resistance mechanisms of the tumor microenvironment. These suppressive programs are myriad, different between patients with ostensibly the same cancer type, and can harness multiple cell types to reinforce their stability. Consequently, the overall benefit of monotherapies remains limited. Cutting-edge technologies now allow for extensive tumor profiling, which can be used to define tumor cell intrinsic and extrinsic pathways of primary and/or acquired immune resistance, herein referred to as features or feature sets of immune resistance to current therapies. We propose that cancers can be characterized by immune resistance archetypes, comprised of five feature sets encompassing known immune resistance mechanisms. Archetypes of resistance may inform new therapeutic strategies that concurrently address multiple cell axes and/or suppressive mechanisms, and clinicians may consequently be able to prioritize targeted therapy combinations for individual patients to improve overall efficacy and outcomes.

Blockade of interleukin 10 potentiates antitumour immune function in human colorectal cancer liver metastases

OBJECTIVE

Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of interleukin 10 (IL-10) blockade on endogenous T cell and chimeric antigen receptor T (CAR-T) cell antitumour function in CRLM slice cultures.

DESIGN

We created organotypic slice cultures from human CRLM (n=38 patients' tumours) and tested the antitumour effects of a neutralising antibody against IL-10 (αIL-10) both alone as treatment and in combination with exogenously administered carcinoembryonic antigen (CEA)-specific CAR-T cells. We evaluated slice cultures with single and multiplex immunohistochemistry, in situ hybridisation, single-cell RNA sequencing, reverse-phase protein arrays and time-lapse fluorescent microscopy.

RESULTS

αIL-10 generated a 1.8-fold increase in T cell-mediated carcinoma cell death in human CRLM slice cultures. αIL-10 significantly increased proportions of CD8⁺ T cells without exhaustion transcription changes, and increased human leukocyte antigen - DR isotype (HLA-DR) expression of macrophages. The antitumour effects of αIL-10 were reversed by major histocompatibility complex class I or II (MHC-I or MHC-II) blockade, confirming the essential role of antigen presenting cells. Interrupting IL-10 signalling also rescued murine CAR-T cell proliferation and cytotoxicity from myeloid cell-mediated immunosuppression. In human CRLM slices, αIL-10 increased CEA-specific CAR-T cell activation and CAR-T cell-mediated cytotoxicity, with nearly 70% carcinoma cell apoptosis across multiple human tumours. Pretreatment with an IL-10 receptor blocking antibody also potentiated CAR-T function.

CONCLUSION

Neutralising the effects of IL-10 in human CRLM has therapeutic potential as a stand-alone treatment and to augment the function of adoptively transferred CAR-T cells.

An In Vivo Model of Human Macrophages in Metastatic Melanoma

Despite recent therapeutic progress, advanced melanoma remains lethal for many patients. The composition of the immune tumor microenvironment (TME) has decisive impacts on therapy response and disease outcome, and high-dimensional analyses of patient samples reveal the heterogeneity of the immune TME. Macrophages infiltrate TMEs and generally associate with tumor progression, but the underlying mechanisms are incompletely understood. Because experimental systems are needed to elucidate the functional properties of these cells, we developed a humanized mouse model reconstituted with human immune cells and human melanoma. We used two strains of recipient mice, supporting or not supporting the development of human myeloid cells. We found that human myeloid cells favored metastatic spread of the primary tumor, thereby recapitulating the cancer-supportive role of macrophages. We next analyzed the transcriptome of human immune cells infiltrating tumors versus other tissues. This analysis identified a cluster of myeloid cells present in the TME, but not in other tissues, which do not correspond to canonical M2 cells. The transcriptome of these cells is characterized by high expression of glycolytic enzymes and multiple chemokines and by low expression of gene sets associated with inflammation and adaptive immunity. Compared with humanized mouse results, we found transcriptionally similar myeloid cells in patient-derived samples of melanoma and other cancer types. The humanized mouse model described here thus complements patient sample analyses, enabling further elucidation of fundamental principles in melanoma biology beyond M1/M2 macrophage polarization. The model can also support the development and evaluation of candidate antitumor therapies.

Gastrointestinal Stromal Tumor

Over the past 20 years, gastrointestinal stromal tumor (GIST) has evolved into an increasingly complex clinical entity with ever more challenges. While surgical resection is the gold standard, advancements in genetic testing, therapeutic options, immunotherapy, and management of metastatic disease necessitate a comprehensive, multimodal approach for these tumors. This chapter highlights the importance of genomic testing of GIST, the use of neoadjuvant and adjuvant therapy for localized disease, surgical principles for GIST, as well as current and new approaches for addressing metastatic disease.

Neoadjuvant Therapy Induces a Potent Immune Response to Sarcoma, Dominated by Myeloid and B Cells

PURPOSE

To characterize changes in the soft-tissue sarcoma (STS) tumor immune microenvironment induced by standard neoadjuvant therapy with the goal of informing neoadjuvant immunotherapy trial design.

EXPERIMENTAL DESIGN

Paired pre- and postneoadjuvant therapy specimens were retrospectively identified for 32 patients with STSs and analyzed by three modalities: multiplexed IHC, NanoString, and RNA sequencing with ImmunoPrism analysis.

RESULTS

All 32 patients, representing a variety of STS histologic subtypes, received neoadjuvant radiotherapy and 21 (66%) received chemotherapy prior to radiotherapy. The most prevalent immune cells in the tumor before neoadjuvant therapy were myeloid cells (45% of all immune cells) and B cells (37%), with T (13%) and natural killer (NK) cells (5%) also present. Neoadjuvant therapy significantly increased the total immune cells infiltrating the tumors across all histologic subtypes for patients receiving neoadjuvant radiotherapy with or without chemotherapy. An increase in the percentage of monocytes and macrophages, particularly M2 macrophages, B cells, and CD4+ T cells was observed postneoadjuvant therapy. Upregulation of genes and cytokines associated with antigen presentation was also observed, and a favorable pathologic response (≥90% necrosis postneoadjuvant therapy) was associated with an increase in monocytic infiltrate. Upregulation of the T-cell checkpoint TIM3 and downregulation of OX40 were observed posttreatment.

CONCLUSIONS

Standard neoadjuvant therapy induces both immunostimulatory and immunosuppressive effects within a complex sarcoma microenvironment dominated by myeloid and B cells. This work informs ongoing efforts to incorporate immune checkpoint inhibitors and novel immunotherapies into the neoadjuvant setting for STSs.

Neoantigen-specific CD4+ T cells in human melanoma have diverse differentiation states and correlate with CD8+ T cell, macrophage, and B cell function

CD4⁺ T cells that recognize tumor antigens are required for immune checkpoint inhibitor efficacy in murine models, but their contributions in human cancer are unclear. We used single-cell RNA sequencing and T cell receptor sequences to identify signatures and functional correlates of tumor-specific CD4⁺ T cells infiltrating human melanoma. Conventional CD4⁺ T cells that recognize tumor neoantigens express CXCL13 and are subdivided into clusters expressing memory and T follicular helper markers, and those expressing cytolytic markers, inhibitory receptors, and IFN-γ. The frequency of CXCL13⁺ CD4⁺ T cells in the tumor correlated with the transcriptional states of CD8⁺ T cells and macrophages, maturation of B cells, and patient survival. Similar correlations were observed in a breast cancer cohort. These results identify phenotypes and functional correlates of tumor-specific CD4⁺ T cells in melanoma and suggest the possibility of using such cells to modify the tumor microenvironment.

Is Chemotherapy Associated with Improved Overall Survival in Patients with Dedifferentiated Chondrosarcoma? A SEER Database Analysis

BACKGROUND

Dedifferentiated chondrosarcoma is a chondrosarcoma subtype associated with high rates of recurrence and a poor prognosis. Others have proposed treatment of dedifferentiated chondrosarcoma using osteosarcoma protocols, including perioperative chemotherapy. However, the rarity of this condition poses difficulties in undertaking single- institution studies of sufficient sample size.

QUESTION/PURPOSE

Is perioperative chemotherapy associated with improved overall survival in patients with dedifferentiated chondrosarcoma?

METHODS

We queried the Surveillance, Epidemiology, and End Results (SEER) 1973 to 2016 database for patients with a diagnosis of dedifferentiated chondrosarcoma (n = 308). As dedifferentiated chondrosarcoma was only classified as a distinct entity in SEER starting in 2000, only patients treated in 2000 and later were included. We excluded from our analyses those patients with distant disease at diagnosis, a primary site of disease other than bone or joints, and those who did not receive cancer-directed surgery. These criteria yielded 185 dedifferentiated chondrosarcoma patients for inclusion. We used Kaplan-Meier analyses and Cox proportional hazards models to assess the association of clinical, demographic, and treatment characteristics on overall survival (OS).

RESULTS

After controlling for confounding variables, including age, sex, tumor size, stage, grade, location, and radiation treatment status, and after adjusting for missing data, no overall survival benefit was associated with receipt of chemotherapy in patients with dedifferentiated chondrosarcoma (hazard ratio 0.75 [95% confidence interval 0.49 to 1.12]; p = 0.16).

CONCLUSION

Chemotherapy treatment of dedifferentiated chondrosarcoma was not associated with improved OS. These results must be viewed cautiously, given the limited granularity of information on chemotherapy treatment, the concerns regarding chemotherapy misclassification in SEER data, and the small sample of patients with dedifferentiated chondrosarcoma, all of which limit the power to detect a difference. Our findings are nevertheless consistent with those of prior reports in which no benefit of chemotherapy could be detected. Lack of clear benefit from perioperative chemotherapy in dedifferentiated chondrosarcoma argues that it should be used only after careful consideration, and ideally in the context of a clinical trial.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Abstract P037: Interleukin-10 is a dominant and reversible mechanism of immune evasion in human colorectal cancer liver metastasis

Background: Colorectal cancer liver metastasis (CRLM) causes major morbidity and mortality. Improved systemic therapies are crucial. We previously reported that macrophages infiltrated CRLM and expressed the immunosuppressive cytokine interleukin-10 (IL-10). In patient-derived CRLM tumor slice cultures, we found that a neutralizing antibody against IL-10 (anti-IL-10) caused tumor apoptosis. Here, we investigated the efficacy and immune-dependent mechanisms of IL-10 blockade in a larger cohort of CRLM patients.

Methods: Tumor specimens were obtained from consenting patients at the time of surgery and cut into 250mm-thick tumor slice cultures as previously described. Tumor slices were treated with control or neutralizing antibodies against programmed cell death protein 1 (PD-1, EH12.1), IL-10 (JES3-9D7), IL-10 receptor alpha (IL-10RA, 3F9), major histocompatibility complex (MHC) class I (G46-2.6) or class II (Tu39). After 4-6 days of treatment, tumor apoptosis was evaluated by cleaved caspase-3 (CC3) immunohistochemistry (IHC) or terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Tumors were evaluated by IHC and in situ hybridization (ISH) for immune markers. Student's t-test, paired t-test, or 1-way ANOVA was used as indicated. p < 0.05 was defined as significant.

Results: We generated tumor slice cultures from 34 unique CRLM patients, 76% (26/34) of whom received preoperative chemotherapy, and all of whom had either microsatellite stable tumors (76%, 26/34) or unknown microsatellite status. Anti-PD-1 did not generate tumor apoptosis (n = 4 patients' tumors). In contrast, anti-IL-10 caused nearly 2-fold increased tumor apoptosis compared with control, in the majority of 34 CRLM patients' tumors evaluated (median 50.1% versus 27.4% apoptotic cells, p < 0.0001). IL-10 receptor blockade generated a similar but non-significant increase in apoptosis. Tumors treated with anti-IL-10 demonstrated increased frequency of CD8+ T cells (median 17.8% versus 7.0% of total cells, n = 5 patients' tumors, p = 0.02) and a non-significant increase in activated PD-1+CD3+ T cells. IL-10 blockade also increased tumor IFNG expression (median 2.9 versus 2.3 counts per total cell number, n = 6 patients' tumors, p < 0.05). Macrophage frequency did not increase, but MHC class II expression nearly doubled (median 19.5% versus 11.5% of total cells, n = 5 patients' tumors, p = 0.02). To test which immune cells were required for anti-IL-10 effect, we treated human CRLM slices with anti-IL-10 +/- blocking antibodies against MHC class I or II. In the 3 of 4 patients' tumors that responded to anti-IL-10, the effect was nearly completely reversed by aMHC-I or aMHC-II (p = 0.0005).

Conclusion: IL-10 is a dominant and reversible mechanism of immune evasion in human CRLM. IL-10 blockade nearly doubled tumor apoptosis in a heterogeneous cohort of CRLM patients' tumors, through a mechanism that required intact CD8+ T cell and antigen-presenting cell function. IL-10 is a compelling immunotherapeutic target for CRLM.

Citation Format: Teresa S. Kim, Kevin Sullivan, Xiuyun Jiang, Cynthia Hsu, Kevin Labadie, Karan Kohli, Heidi Kenerson, Sara Daniel, Arezou Abbasi, Raymond Yeung, Venu Pillarisetty. Interleukin-10 is a dominant and reversible mechanism of immune evasion in human colorectal cancer liver metastasis [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P037.

Key chemokines direct migration of immune cells in solid tumors

Immune cell infiltration into solid tumors, their movement within the tumor microenvironment (TME), and interaction with other immune cells are controlled by their directed migration towards gradients of chemokines. Dysregulated chemokine signaling in TME favors the growth of tumors, exclusion of effector immune cells, and abundance of immunosuppressive cells. Key chemokines directing the migration of immune cells into tumor tissue have been identified. In this review, we discuss well-studied chemokine receptors that regulate migration of effector and immunosuppressive immune cells in the context of cancer immunology. We discuss preclinical models that have described the role of respective chemokine receptors in immune cell migration into TME and review preclinical and clinical studies that target chemokine signaling as standalone or combination therapies.

CD4+ T cell and M2 macrophage infiltration predict dedifferentiated liposarcoma patient outcomes

Background

Dedifferentiated liposarcoma (DDLPS) is one of the most common soft tissue sarcoma subtypes and is devastating in the advanced/metastatic stage. Despite the observation of clinical responses to PD-1 inhibitors, little is known about the immune microenvironment in relation to patient prognosis.

Methods

We performed a retrospective study of 61 patients with DDLPS. We completed deep sequencing of the T-cell receptor (TCR) β-chain and RNA sequencing for predictive modeling, evaluating both immune markers and tumor escape genes. Hierarchical clustering and recursive partitioning were employed to elucidate relationships of cellular infiltrates within the tumor microenvironment, while an immune score for single markers was created as a predictive tool.

Results

Although many DDLPS samples had low TCR clonality, high TCR clonality combined with low T-cell fraction predicted lower 3-year overall survival (p=0.05). Higher levels of CD14+ monocytes (p=0.02) inversely correlated with 3-year recurrence-free survival (RFS), while CD4+ T-cell infiltration (p=0.05) was associated with a higher RFS. Genes associated with longer RFS included PD-1 (p=0.003), ICOS (p=0.006), BTLA (p=0.033), and CTLA4 (p=0.02). In a composite immune score, CD4+ T cells had the strongest positive predictive value, while CD14+ monocytes and M2 macrophages had the strongest negative predictive values.

Conclusions

Immune cell infiltration predicts clinical outcome in DDLPS, with CD4+ cells associated with better outcomes; CD14+ cells and M2 macrophages are associated with worse outcomes. Future checkpoint inhibitor studies in DDLPS should incorporate immunosequencing and gene expression profiling techniques that can generate immune landscape profiles.

Abstract 607: IL-15 is the most potent of tested gamma chain cytokines at inducing in situ proliferation of T cells in human pancreatic cancer

Background: Multiple factors, including dense stroma and high infiltration of suppressive immune cells make pancreatic ductal adenocarcinoma (PDA) challenging to treat with immunotherapy. The presence of intra-tumoral T cells positively correlates with improved survival for PDA patients. Gamma chain cytokines (GCCs) can augment T cell mediated anti-tumor immunity and various GCC agonist drugs have been applied in clinical trials for cancer. Besides evaluating the effect of GCC derived agonists using recovered blood or biopsies of treated patients, it is challenging to mechanistically study the effect of GCCs on tumor-resident immune cells in human samples.

Methods: Here we apply organotypic slice culture of surgically resected tumor tissues to study the effect of GCCs on intra-tumoral immune cells. We treated slices of PDAs with GCCs (IL-2, IL-7, IL-15 and IL-21) for 6 days. Immune cells, especially T cells emigrated from the tumor slices into the culture supernatant. On day 6 we fixed intact tumor slices for multiplex immunohistochemistry (mIHC) and analyzed emigrated cells using flow cytometry.

Results: IL-15 and IL-7 potently induced T cell proliferation. The effect of IL-7 and IL-15 on T cell proliferation was higher for T cells that expressed markers of antigen experience such as CD39 and PD1 (Table 1). While IL-15 had the strongest effect on tumor-derived T cells, IL-15 and IL-7 were similar in their effect on T cells in the blood of the same patient, suggesting that IL-15 is especially effective in inducing the proliferation of tumor-infiltrating T cells. The effect of IL-15 on enhanced T cell proliferation was also seen within tumor slices, as revealed by mIHC.

Conclusion: Our data suggest that IL-15 is the most potent GCC at inducing in situ expansion of tumor-resident T cells, including T cells that show signs of antigen experience.

Table 1.IL-15 induces in situ T cell proliferation in PDA.AssayGroupsUntreatedIL-2IL-7IL-15IL-21ParameterFlow Cytometry%Ki67+CD8+cells of live cells0.090.040.360.595.001.3514.331.200.310.14%CD39+CD103+of CD8+0.130.150.110.040.290.140.620.180.130.08%PD1+of CD8+25.107.2223.233.1030.484.7446.483.5037.402.32mIHC%CD8+Ki67+ of all cells0.16 0.04(n=2)0.83 (n=1)0.550.38(n=2)2.200.04(n=2)0.490.41(n=2)n=4 slices for each group for flow cytometry. Data are from one experiment*. MeanSD is shown. Two doses (10-fold difference) for each cytokine were tested and results only for the low dose are shown.*Another experiment with groups IL-2 and IL-2+IL-15 was performed and had similar results for the effect of IL-15

Citation Format: Karan Kohli, Shihong Zhang, Xiuyun Jiang, Cynthia Hsu, Arezou Abbasi, Teresa S. Kim, Venu G. Pillarisetty. IL-15 is the most potent of tested gamma chain cytokines at inducing in situ proliferation of T cells in human pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 607.

Ribosomal protein S3 associates with the TFIIH complex and positively regulates nucleotide excision repair

In mammalian cells, the bulky DNA adducts caused by ultraviolet radiation are mainly repaired via the nucleotide excision repair (NER) pathway; some defects in this pathway lead to a genetic disorder known as xeroderma pigmentosum (XP). Ribosomal protein S3 (rpS3), a constituent of the 40S ribosomal subunit, is a multi-functional protein with various extra-ribosomal functions, including a role in the cellular stress response and DNA repair-related activities. We report that rpS3 associates with transcription factor IIH (TFIIH) via an interaction with the xeroderma pigmentosum complementation group D (XPD) protein and complements its function in the NER pathway. For optimal repair of UV-induced duplex DNA lesions, the strong helicase activity of the TFIIH complex is required for unwinding damaged DNA around the lesion. Here, we show that XP-D cells overexpressing rpS3 showed markedly increased resistance to UV radiation through XPD and rpS3 interaction. Additionally, the knockdown of rpS3 caused reduced NER efficiency in HeLa cells and the overexpression of rpS3 partially restored helicase activity of the TFIIH complex of XP-D cells in vitro. We also present data suggesting that rpS3 is involved in post-excision processing in NER, assisting TFIIH in expediting the repair process by increasing its turnover rate when DNA is damaged. We propose that rpS3 is an accessory protein of the NER pathway and its recruitment to the repair machinery augments repair efficiency upon UV damage by enhancing XPD helicase function and increasing its turnover rate.

Correction to: Rates of TP53 Mutation are Significantly Elevated in African American Patients with Gastric Cancer

In the original article Kaitlin C. McLoughlin's name is spelled incorrectly. It is correct as reflected here.

Age-Specific Incidence of Melanoma in the United States

Importance

Melanoma is epidemiologically linked to UV exposure, particularly childhood sunburn. Public health campaigns are increasing sun-protective behavior in the United States, but the effect on melanoma incidence is unknown.

Objective

To examine the incidence of melanoma in the United States and whether any age-specific differences are present.

Design, Setting, and Participants

Observational, population-based registry data were extracted on July 3, 2018, from the combined National Program of Cancer Registries-Surveillance Epidemiology and End Results United States Cancer Statistics database for 2001-2015. Deidentified data for 988 103 cases of invasive melanoma, with International Classification of Diseases for Oncology histologic categorization codes 8720 to 8790, were used for analysis. Data analysis was performed from July 1, 2018, to March 1, 2019.

Main Outcomes and Measures

The annual rates of melanoma in pediatric, adolescent, young adult, and adult age groups were determined. Analyses were stratified by sex, and incidence rates were age-adjusted to the 2000 US standard population. Annual percentage change (APC) in incidence rate was calculated over the most recent decade for which data were available (2006-2015) using the weighted least squares method.

Results

In 2015, 83 362 cases of invasive melanoma were reported in the United States, including 67 in children younger than 10 years, 251 in adolescents (10-19 years), and 1973 in young adults (20-29 years). Between 2006 and 2015, the overall incidence rate increased from 200.1 to 229.1 cases per million person-years. In adults aged 40 years or older, melanoma rates increased by an APC of 1.8% in both men (95% CI, 1.4%-2.1%) and women (95% CI, 1.4%-2.2%). In contrast, clinically and statistically significant decreases were seen in melanoma incidence for adolescents and young adults. Specifically, incidence rates decreased by an APC of -4.4% for male adolescents (95% CI, -1.7% to -7.0%), -5.4% for female adolescents (95% CI, -3.3% to -7.4%), -3.7% for male young adults (95% CI, -2.5% to -4.8%), and -3.6% for female young adults (95% CI, -2.8% to -4.5%). Data on skin pigmentation and sun protection history were unavailable; similar trends were observed with data limited to non-Hispanic whites. Young adult women appeared to have twice the risk of melanoma as young adult men.

Conclusions and Relevance

The incidence of invasive melanoma in the United States appeared to decrease in adolescents and young adults from 2006 to 2015, and this finding contrasted with increases in older populations. These incidence trends suggest that public health efforts may be favorably influencing melanoma incidence in the United States.

Long-term Outcomes for Extraskeletal Myxoid Chondrosarcoma: A SEER Database Analysis

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMCS) is a rare tumor that typically has an indolent course but high rate of recurrence. We queried the Surveillance, Epidemiology, and End Results (SEER) database to assess factors associated with metastasis, treatment, and survival.

METHODS

We queried the SEER 1973-2016 database for patients with myxoid chondrosarcoma (ICD-O-3: 9231/3). Kaplan-Meier analyses and Cox proportional hazard models assessed effects on overall survival (OS) of demographics and clinical characteristics. Logistic regression assessed associations between tumor location and distant disease. Primary analysis was a complete case analysis; multiple imputation (MI) was used in a sensitivity analysis.

RESULTS

Locoregional disease (LRD) was found in 373 (85%) of patients. In univariate analysis with LRD, surgery correlated with superior OS [HR = 0.27; 95% confidence interval (CI), 0.16-0.47]; chemotherapy and radiotherapy associated with inferior OS (HR = 1.90; 95% CI, 1.11-3.27 and HR = 1.45; 95% CI, 1.03-2.06, respectively). No treatment modality associated with OS in the adjusted, complete case model. In the adjusted sensitivity analysis, surgery associated with superior outcomes (HR = 0.36; 95% CI, 0.19-0.69). There was no OS difference by primary tumor site. 10-year OS with distant disease was 10% (95% CI, 2%-25%).

CONCLUSIONS

Surgery in LRD associated with improved OS in univariate analysis and adjusted models correcting for missing data. There was no OS benefit with chemotherapy or radiotherapy.

IMPACT

This represents the largest report of EMCS with long-term follow-up. Despite the reputedly indolent nature of EMCS, outcomes with metastatic disease are poor. We provide OS benchmarks and guidance for stratification in future prospective trials.

Targeting NLRP3 Inflammasome Reduces Age-Related Experimental Alveolar Bone Loss

The cause of chronic inflammatory periodontitis, which leads to the destruction of periodontal ligament and alveolar bone, is multifactorial. An increasing number of studies have shown the clinical significance of NLRP3-mediated low-grade inflammation in degenerative disorders, but its causal linkage to age-related periodontitis has not yet been elucidated. In this study, we investigated the involvement of the NLRP3 inflammasome and the therapeutic potential of NLRP3 inhibition in age-related alveolar bone loss by using in vivo and in vitro models. The poor quality of alveolar bones in aged mice was correlated with caspase-1 activation by macrophages and elevated levels of IL-1β, which are mainly regulated by the NLRP3 inflammasome, in periodontal ligament and serum, respectively. Aged mice lacking Nlrp3 showed better bone mass than age-matched wild-type mice via a way that affects bone resorption rather than bone formation. In line with this finding, treatment with MCC950, a potent inhibitor of the NLRP3 inflammasome, significantly suppressed alveolar bone loss with reduced caspase-1 activation in aged mice but not in young mice. In addition, our in vitro studies showed that the addition of IL-1β encourages RANKL-induced osteoclastogenesis from bone marrow-derived macrophages and that treatment with MCC950 significantly suppresses osteoclastic differentiation directly, irrelevant to the inhibition of IL-1β production. Our results suggest that the NLRP3 inflammasome is a critical mediator in age-related alveolar bone loss and that targeting the NLRP3 inflammasome could be a novel option for controlling periodontal degenerative changes with age.

Enhanced antimicrobial stewardship based on rapid phenotypic antimicrobial susceptibility testing for bacteraemia in patients with haematological malignancies: a randomized controlled trial

OBJECTIVES

Recently, rapid phenotypic antimicrobial susceptibility testing (AST) based on microscopic imaging analysis has been developed. The aim of this study was to determine whether implementation of antimicrobial stewardship programmes (ASP) based on rapid phenotypic AST can increase the proportion of patients with haematological malignancies who receive optimal targeted antibiotics during early periods of bacteraemia.

METHODS

This randomized controlled trial enrolled patients with haematological malignancies and at least one positive blood culture. Patients were randomly assigned 1:1 to conventional (n = 60) or rapid phenotypic (n = 56) AST. The primary outcome was the proportion of patients receiving optimal targeted antibiotics 72 hr after blood collection for culture.

RESULTS

The percentage receiving optimal targeted antibiotics at 72 hr was significantly higher in the rapid phenotypic AST group (45/56, 80.4%) than in conventional AST group (34/60, 56.7%) (relative risk (RR) 1.42, 95% confidence interval (CI) 1.09-1.83). The percentage receiving unnecessary broad-spectrum antibiotics at 72 hr was significantly lower (7/26, 12.5% vs 18/60, 30.0%; RR 0.42, 95% CI 0.19-0.92) and the mean time to optimal targeted antibiotic treatment was significantly shorter (38.1, standard deviation (SD) 38.2 vs 72.8, SD 93.0 hr; p < 0.001) in the rapid phenotypic AST group. The mean time from blood collection to the AST result was significantly shorter in the rapid phenotypic AST group (48.3, SD 17.6 vs 83.1, SD 22.2 hr).

DISCUSSION

ASP based on rapid phenotypic AST can rapidly optimize antibiotic treatment for bacteraemia in patients with haematological malignancy. Rapid phenotypic AST can improve antimicrobial stewardship in immunocompromised patients.

Abstract 4489: IL-10 blockade reactivates antitumor immunity in human colorectal cancer liver metastases

Background: Colorectal cancer (CRC) is the 4th most common cancer in the US, and the liver is the most common site of metastatic disease. Immune checkpoint inhibitor therapy has not been successful in achieving a clinical response in most patients with CRC liver metastases (CRCLM). The liver is known to induce tolerance to foreign antigens as a result of immunosuppressive cytokines including IL-10. We hypothesized that blockade of IL-10 signaling in CRCLM would potentiate tumor infiltrating lymphocyte (TIL)-mediated tumor cell death.

Methods: We performed single-cell RNA sequencing (scRNAseq) of CRCLM using the 10x platform to evaluate for expression of IL-10 or IL-10 receptor (IL-10R) RNA within the tumor (n=8). To confirm if the IL-10R protein was present within the tumor microenvironment (TME), we also performed immunohistochemistry (IHC) (n=3). In order to study the functional effects of IL-10 blockade, we utilized a tumor slice culture (TSC) model, which allows for the study of cancers with their intact TME including immune cells. For TSCs, cores (6 mm diameter) were taken from freshly resected sterile human CRCLM and cut to 250 µm thick slices using a vibratome (n=3). Duplicate slices were treated with either IgG control or anti-IL-10 monoclonal antibodies and cultured for up to 6 days. To evaluate for histological evidence of necrosis and cell apoptosis within the tumor slice, we stained slides with either hematoxylin and eosin (H&E) or cleaved-Caspase-3 (CC3). To gain insight into the activation state of TIL after treatment, we measured levels of cytokines within the culture supernatants.

Results: We found by scRNAseq that that IL-10 was expressed by a subset of tumor-associated macrophages, and IL-10R was expressed by both CD4+ and CD8+ T cells as well as macrophages. We confirmed that IL-10R protein was present within the CRCLM TME by IHC, and IL-10R expression was distributed throughout the stroma in non-tumor cells. In TSC treated with anti-IL-10 antibody, CC3+ cells were found to be 82.8% of total cells, compared to 36.1% of control (p = 1 x 10-6) at day 6. These findings were consistent across all human tumor samples treated with IL-10 blockade versus control at all time points examined. Furthermore, IL-10 blockade led to histologic evidence of generalized necrosis compared to an intact TME seen in the control group. Analysis of cytokines released into the media confirmed that IL-10 was present in controls, but absent in slices blocked with anti-IL-10 antibody. We also found increased levels of granzyme B, IL-2, GM-CSF, and IL-18, as well as a reduction in the immune checkpoint receptor TIM3, after one day of IL-10 blockade in culture.

Conclusion: Treatment of human CRCLM TSCs with anti-IL-10 antibody leads to a marked increase in immune-mediated cell death within the tumor. Our data suggest that IL-10 serves as a critical regulator of anti-tumor immunity in the CRCLM TME and may serve as an important immunotherapeutic target.

Citation Format: Kevin M. Sullivan, Xiuyun Jiang, Yongwoo David Seo, Heidi L. Kenerson, Xiaowei Yan, Chris Lausted, Changting Meng, Neda Jabbari, Kevin P. Labadie, Sara K. Daniel, Qiang Tian, Teresa S. Kim, Raymond S. Yeung, Venu G. Pillarisetty. IL-10 blockade reactivates antitumor immunity in human colorectal cancer liver metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4489.

Mobilization of CD8+ T Cells via CXCR4 Blockade Facilitates PD-1 Checkpoint Therapy in Human Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDA) is rarely cured, and single-agent immune checkpoint inhibition has not demonstrated clinical benefit despite the presence of large numbers of CD8⁺ T cells. We hypothesized that tumor-infiltrating CD8⁺ T cells harbor latent antitumor activity that can be reactivated using combination immunotherapy.

EXPERIMENTAL DESIGN

Preserved human PDA specimens were analyzed using multiplex IHC (mIHC) and T-cell receptor (TCR) sequencing. Fresh tumor was treated in organotypic slice culture to test the effects of combination PD-1 and CXCR4 blockade. Slices were analyzed using IHC, flow cytometry, and live fluorescent microscopy to assess tumor kill, in addition to T-cell expansion and mobilization.

RESULTS

mIHC demonstrated fewer CD8⁺ T cells in juxtatumoral stroma containing carcinoma cells than in stroma devoid of them. Using TCR sequencing, we found clonal expansion in each tumor; high-frequency clones had multiple DNA rearrangements coding for the same amino acid binding sequence, which suggests response to common tumor antigens. Treatment of fresh human PDA slices with combination PD-1 and CXCR4 blockade led to increased tumor cell death concomitant with lymphocyte expansion. Live microscopy after combination therapy demonstrated CD8⁺ T-cell migration into the juxtatumoral compartment and rapid increase in tumor cell apoptosis.

CONCLUSIONS

Endogenous tumor-reactive T cells are present within the human PDA tumor microenvironment and can be reactivated by combined blockade of PD-1 and CXCR4. This provides a new basis for the rational selection of combination immunotherapy for PDA.See related commentary by Medina and Miller, p. 3747.

Rates of TP53 Mutation are Significantly Elevated in African American Patients with Gastric Cancer

BACKGROUND

Gastric adenocarcinoma is a heterogenous disease that results from complex interactions between environmental and genetic factors, which may contribute to the disparate outcomes observed between different patient populations. This study aimed to determine whether genomic differences exist in a diverse population of patients by evaluating tumor mutational profiles stratified by race.

METHODS

All patients with gastric adenocarcinoma between 2012 and 2016 who underwent targeted next-generation sequencing of cancer genes by the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets platform were identified. Patient race was categorized as Asian, African American, Hispanic, or Caucasian. Fisher's exact test was used to examine differences in mutation rates between racial designations for the most common mutations identified. The p values in this study were adjusted using the false discovery rate method.

RESULTS

The study investigated 595 mutations in 119 patients. The DNA alterations identified included missense mutations (66%), frame-shift deletions (13%), and nonsense mutations (9%). Silent mutations were excluded. The most frequently mutated genes were ARID1A, CDH1, ERBB3, KRAS, PIK3CA, and TP53. Of these, TP53 was the most frequently mutated gene, affecting 50% of patients. The proportion of patients with TP53 mutations differed significantly between races (p = 0.012). The findings showed TP53 mutations for 89% (16/18) of the African American patients, 56% (10/18) of the Asian patients, 43% (9/21) of the Hispanic patients, and 40% (25/62) of the Caucasian patients.

CONCLUSIONS

Significantly higher rates of TP53 mutations were identified among the African American patients with gastric adenocarcinoma. This is the first study to evaluate tumor genomic differences in a diverse population of patients with gastric adenocarcinoma.

Standardisation of defined approaches for skin sensitisation testing to support regulatory use and international adoption: position of the International Cooperation on Alternative Test Methods

Skin sensitisation is the regulatory endpoint that has been at the centre of concerted efforts to replace animal testing in recent years, as demonstrated by the Organisation for Economic Co-operation and Development (OECD) adoption of five non-animal methods addressing mechanisms under the first three key events of the skin sensitisation adverse outcome pathway. Nevertheless, the currently adopted methods, when used in isolation, are not sufficient to fulfil regulatory requirements on the skin sensitisation potential and potency of chemicals comparable to that provided by the regulatory animal tests. For this reason, a number of defined approaches integrating data from these methods with other relevant information have been proposed and documented by the OECD. With the aim to further enhance regulatory consideration and adoption of defined approaches, the European Union Reference Laboratory for Alternatives to Animal testing in collaboration with the International Cooperation on Alternative Test Methods hosted, on 4-5 October 2016, a workshop on the international regulatory applicability and acceptance of alternative non-animal approaches, i.e., defined approaches, to skin sensitisation assessment of chemicals used in a variety of sectors. The workshop convened representatives from more than 20 regulatory authorities from the European Union, United States, Canada, Japan, South Korea, Brazil and China. There was a general consensus among the workshop participants that to maximise global regulatory acceptance of data generated with defined approaches, international harmonisation and standardisation are needed. Potential assessment criteria were defined for a systematic evaluation of existing defined approaches that would facilitate their translation into international standards, e.g., into a performance-based Test Guideline. Informed by the discussions at the workshop, the ICATM members propose practical ways to further promote the regulatory use and facilitate adoption of defined approaches for skin sensitisation assessments.

ETV4 collaborates with Wnt/β-catenin signaling to alter cell cycle activity and promote tumor aggressiveness in gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common sarcoma, often resulting from a KIT or platelet-derived growth factor receptor alpha (PDGFRA) mutation. The lineage transcription factor ETV1 is expressed similarly in GISTs regardless of malignant potential. Although the related transcription factor ETV4 has been associated with metastasis and tumor progression in other cancers, its role in GIST is unknown. In this study, we found that ETV4 levels were high in a subset of human GISTs and correlated with high mitotic rate. Through Gene Set Enrichment Analysis in selected human GISTs, we identified a relationship between ETV4 levels and β-catenin signaling, especially in advanced GISTs. GIST specimens with high ETV4 levels overexpressed cell cycle regulating genes and had aberrant activation of the canonical Wnt pathway. In human GIST cell lines, ETV4 RNA interference suppressed cell cycle genes and Wnt/β-catenin signaling. ETV4 knockdown also reduced tumor cell proliferation, invasion, and tumor growth in vivo. Conversely, ETV4 overexpression increased cyclin D1 expression and Wnt/β-catenin signaling. Moreover, we determined that ETV4 knockdown destabilized nuclear β-catenin and increased its degradation via COP1, an E3 ligase involved in both ETV4 and β-catenin turnover. Aberrant accumulation of ETV4 and nuclear β-catenin was found in patient derived xenografts created from metastatic GISTs that became resistant to tyrosine kinase inhibitors. Collectively, our findings highlight the significance of ETV4 expression in GIST and identify ETV4 as a biomarker in human GISTs.

Wnt/β-catenin Signaling Contributes to Tumor Malignancy and Is Targetable in Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumor (GIST) is the most common type of sarcoma and usually harbors either a KIT or PDGFRA mutation. However, the molecular basis for tumor malignancy is not well defined. Although the Wnt/β-catenin signaling pathway is important in a variety of cancers, its role in GIST is uncertain. Through analysis of nearly 150 human GIST specimens, we found that some human GISTs expressed β-catenin and contained active, dephosphorylated nuclear β-catenin. Furthermore, advanced human GISTs expressed reduced levels of the Wnt antagonist DKK4. Accordingly, in human GIST T1 cells, Wnt stimulation increased β-catenin-mediated transcriptional activity in a reporter assay as well as transcription of the downstream target genes Axin2 and CCND1 In contrast, DKK4 overexpression in GIST T1 cells reduced Wnt/β-catenin signaling. In addition, we showed that nuclear β-catenin stability was partially regulated by the E3 ligase COP1, as demonstrated with coimmunoprecipitation and COP1 knockdown. Three molecular inhibitors of the Wnt/β-catenin pathway demonstrated antitumor efficacy in various GIST models, both in vitro and in vivo Notably, the tankyrase inhibitor G007-LK alone had substantial activity against tumors of genetically engineered Kit^V558Δ/+ mice, and the effect was increased by the addition of the Kit inhibitor imatinib mesylate. Collectively, our findings demonstrate that Wnt/β-catenin signaling is a novel therapeutic target for selected untreated or imatinib-resistant GISTs. Mol Cancer Ther; 16(9); 1954-66. ©2017 AACR.

Genome and transcriptome profiling of fibrolamellar hepatocellular carcinoma demonstrates p53 and IGF2BP1 dysregulation

Fibrolamellar hepatocellular carcinoma (FL-HCC) is a rare variant of HCC that most frequently affects young adults. Because of its rarity and an absence of preclinical models, our understanding of FL-HCC is limited. Our objective was to analyze chromosomal alterations and dysregulated gene expression in tumor specimens collected at a single center during two decades of experience with FL-HCC. We analyzed 38 specimens from 26 patients by array comparative genomic hybridiziation (aCGH) and 35 specimens from 15 patients by transcriptome sequencing (RNA-seq). All tumor specimens exhibited genomic instability, with a higher frequency of genomic amplifications or deletions in metastatic tumors. The regions encoding 71 microRNAs (miRs) were deleted in at least 25% of tumor specimens. Five of these recurrently deleted miRs targeted the insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) gene product, and a correlating 100-fold upregulation of IGF2BP1 mRNA was seen in tumor specimens. Transcriptome analysis demonstrated intrapatient tumor similarity, independent of recurrence site or time. The p53 tumor suppressor pathway was downregulated as demonstrated by both aCGH and RNA-seq analysis. Notch, EGFR, NRAS, and RB1 pathways were also significantly dysregulated in tumors compared with normal liver tissue. The findings illuminate the genomic and transcriptomic landscape of this rare disease and provide insight into dysregulated oncogenic pathways and potential therapeutic targets in FL-HCC.

PD-1/PD-L1 Blockade Enhances T-cell Activity and Antitumor Efficacy of Imatinib in Gastrointestinal Stromal Tumors

PURPOSE

Tyrosine kinase inhibitors are effective in gastrointestinal stromal tumors (GISTs) but often are of transient benefit as resistance commonly develops. Immunotherapy, particularly blockade of the inhibitory receptor programmed death 1 (PD-1) or the ligand programmed death ligand 1 (PD-L1), has shown effectiveness in a variety of cancers. The functional effects of PD-1/PD-L1 blockade are unknown in GISTs.

EXPERIMENTAL DESIGN

We analyzed tumor and matched blood samples from 85 patients with GISTs and determined the expression of immune checkpoint molecules using flow cytometry. We investigated the combination of imatinib with PD-1/PD-L1 blockade in Kit^V558Δ/+ mice that develop GISTs.

RESULTS

The inhibitory receptors PD-1, lymphocyte activation gene 3, and T-cell immunoglobulin mucin-3 were upregulated on tumor-infiltrating T cells compared with T cells from matched blood. PD-1 expression on T cells was highest in imatinib-treated human GISTs. Meanwhile, intratumoral PD-L1 expression was variable. In human GIST cell lines, treatment with imatinib abrogated the IFNγ-induced upregulation of PD-L1 via STAT1 inhibition. In Kit^V558Δ/+ mice, imatinib downregulated IFNγ-related genes and reduced PD-L1 expression on tumor cells. PD-1 and PD-L1 blockade in vivo each had no efficacy alone but enhanced the antitumor effects of imatinib by increasing T-cell effector function in the presence of KIT and IDO inhibition.

CONCLUSIONS

PD-1/PD-L1 blockade is a promising strategy to improve the effects of targeted therapy in GISTs. Collectively, our results provide the rationale to combine these agents in human GISTs. Clin Cancer Res; 23(2); 454-65. ©2016 AACR.

Evaluation of Xpert(®) MTB/RIF assay: diagnosis and treatment outcomes in rifampicin-resistant tuberculosis

SETTING

The Xpert(®) MTB/RIF assay is endorsed by the World Health Organization for the detection of rifampicin (RMP) resistant tuberculosis (TB).

OBJECTIVE

To evaluate Xpert for its diagnostic accuracy in detecting RMP-resistant TB and its impact on treatment outcomes.

DESIGN

Patients with available phenotypic drug susceptibility testing (DST) results and those in whom RMP-resistant pulmonary TB was diagnosed using Xpert were evaluated. The accuracy and turnaround time (TAT) of Xpert for determining RMP-resistant TB was calculated. The TATs for treatment between patients diagnosed with RMP-resistant TB using Xpert and those diagnosed without the assay (phenotypic DST group) were compared.

RESULTS

In 321 patients, when phenotypic DST was used as the gold standard, Xpert sensitivity and specificity for RMP resistance diagnosis was respectively 100% and 98.7%; the positive and negative predictive values were respectively 86.2% and 100%. The Xpert group had a much shorter interval from initial evaluation to commencing second-line anti-tuberculosis treatment (64 vs. 2 days, P < 0.001), and negative conversion of mycobacterial cultures (197 vs. 62.5 days, P < 0.001) than the phenotypic DST group.

CONCLUSION

Xpert was accurate at diagnosing RMP resistance in this setting with an intermediate TB burden and a low level of RMP resistance. Xpert might reduce disease transmission by reducing the sputum culture conversion times for patients with RMP-resistant TB.

Applicability of the Sparse Temporal Acquisition Technique in Resting-State Brain Network Analysis

BACKGROUND AND PURPOSE

The ability of sparse temporal acquisition to minimize the effect of scanner background noise is of utmost importance in auditory fMRI; however, it has considerably lower temporal efficiency and resolution than the conventional continuous acquisition method. The purpose of this study was to determine whether sparse sampling could be applied to resting-state research by comparing its results with those obtained by using continuous acquisition.

MATERIALS AND METHODS

We identified resting-state networks by using independent component analysis and measured their functional connectivity strength in 14 healthy subjects who underwent two 6-minute sparse (60 volumes) and continuous (360 volumes) imaging sessions. To account for the sample size difference, an additional continuous dataset was generated by temporally matching the continuous dataset to 60 volumes of the sparse dataset.

RESULTS

Consistent resting-state network maps were produced through all 3 datasets. Scanner background noise did not appear to affect the spatial constitution of the networks, whereas a larger sample size influenced it substantially. The strength of the intranetwork connectivity was similar through the 3 datasets.

CONCLUSIONS

Our results indicated that continuous acquisition is a recommended technique that should be applied in most of the resting-state studies due to its superior temporal efficiency and increased statistical power. The use of sparse temporal acquisition should be restricted to very particular conditions when continuous scanner noise is unacceptable.

Modification to the accelerator of the NBI-1B ion source for improving the injection efficiency

Minimizing power loss of a neutral beam imposes modification of the accelerator of the ion source for further improvement of the beam optics. The beam optics can be improved by focusing beamlets. The injection efficiencies by the steering of ion beamlets are investigated numerically to find the optimum modification of the accelerator design of the NBI-1B ion source. The beam power loss was reduced by aperture displacement of three edge beamlets arrays considering power loadings on the beamline components. Successful testing and operation of the ion source at 60 keV/84% of injection efficiency led to the possibility of enhancing the system capability to a 2.4 MW power level at 100 keV/1.9 μP.

Predisposition to and effects of methamphetamine use on the adolescent brain

Adolescence is a period of heightened vulnerability both to addictive behaviors and drug-induced brain damage. Yet, only limited information exists on the brain mechanisms underlying these adolescent-specific characteristics. Moreover, distinctions in brain correlates between predisposition to drug use and effects of drugs in adolescents are unclear. Using cortical thickness and diffusion tensor image analyses, we found greater and more widespread gray and white matter alterations, particularly affecting the frontostriatal system, in adolescent methamphetamine (MA) users compared with adult users. Among adolescent-specific gray matter alterations related to MA use, smaller cortical thickness in the orbitofrontal cortex was associated with family history of drug use. Our findings highlight that the adolescent brain, which undergoes active myelination and maturation, is more vulnerable to MA-related alterations than the adult brain. Furthermore, MA-use-related executive dysfunction was greater in adolescent MA users than in adult users. These findings may provide explanation for the severe behavioral complications and relapses that are common in adolescent-onset drug addiction. Additionally, these results may provide insights into distinguishing the neural mechanisms that underlie the predisposition to drug addiction from effects of drugs in adolescents.

Histologic Analysis of Retrieved Clots in Acute Ischemic Stroke: Correlation with Stroke Etiology and Gradient-Echo MRI

BACKGROUND AND PURPOSE

It is unclear whether clot composition analysis is helpful to predict a stroke mechanism in acute large vessel occlusion. In addition, the relationship between early vessel signs on imaging studies and clot compositions has been poorly understood. The purpose of this study was to elucidate the relationship between clot composition and stroke etiology following mechanical thrombectomy and to investigate the effect of varied clot compositions on gradient-echo MR imaging of clots.

MATERIALS AND METHODS

Histopathologic analysis of retrieved clots from 37 patients with acute MCA occlusion was performed. Patients underwent gradient-echo imaging before endovascular therapy. Retrieved clots underwent semiquantitative proportion analysis to quantify red blood cells, fibrin, platelets, and white blood cells by area. Correlations between clot compositions and stroke subtypes and susceptibility vessel signs on gradient-echo imaging were assessed.

RESULTS

Stroke etiology was classified as cardioembolism in 22 patients (59.4%), large-artery atherosclerosis in 8 (21.6%), and undetermined in 7 (18.9%). The clots from cardioembolism had a significantly higher proportion of red blood cells (37.8% versus 16.9%, P = .031) and a lower proportion of fibrin (32.3% versus 48.5%, P = .044) compared with those from large-artery atherosclerosis. The proportion of red blood cells was significantly higher in clots with a susceptibility vessel sign than in those without it (48.0% versus 1.9%, P < .001), whereas the proportions of fibrin (26.4% versus 57.0%, P < .001) and platelets (22.6% versus 36.9%, P = .011) were significantly higher in clots without a susceptibility vessel sign than those with it.

CONCLUSIONS

The histologic composition of clots retrieved from cerebral arteries in patients with acute stroke differs between those with cardioembolism and large-artery atherosclerosis. In addition, a susceptibility vessel sign on gradient-echo imaging is strongly associated with a high proportion of red blood cells and a low proportion of fibrin and platelets in retrieved clots.

Diagnosis and Management of Pancreatic Cystic Neoplasms

Incidentally discovered pancreatic cystic lesions are increasingly common, affecting up to 10% to 15% of patients undergoing cross-sectional imaging. Although some pancreatic cystic neoplasms harbor invasive malignancy or the potential to progress over time, a majority are benign and can be observed safely. Accurate diagnosis is key to appropriate management. Diagnosis requires a multidisciplinary and multimodal approach. This review discusses each type of pancreatic cystic neoplasm and the current data on diagnosis and treatment.

Pharmacological Inhibition of KIT Activates MET Signaling in Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GIST) are the most common adult sarcomas and the oncogenic driver is usually a KIT or PDGFRA mutation. Although GISTs are often initially sensitive to imatinib or other tyrosine kinase inhibitors, resistance generally develops, necessitating backup strategies for therapy. In this study, we determined that a subset of human GIST specimens that acquired imatinib resistance acquired expression of activated forms of the MET oncogene. MET activation also developed after imatinib therapy in a mouse model of GIST (KitV558del/+ mice), where it was associated with increased tumor hypoxia. MET activation also occurred in imatinib-sensitive human GIST cell lines after imatinib treatment in vitro. MET inhibition by crizotinib or RNA interference was cytotoxic to an imatinib-resistant human GIST cell population. Moreover, combining crizotinib and imatinib was more effective than imatinib alone in imatinib-sensitive GIST models. Finally, cabozantinib, a dual MET and KIT small-molecule inhibitor, was markedly more effective than imatinib in multiple preclinical models of imatinib-sensitive and imatinib-resistant GIST. Collectively, our findings showed that activation of compensatory MET signaling by KIT inhibition may contribute to tumor resistance. Furthermore, our work offered a preclinical proof of concept for MET inhibition by cabozantinib as an effective strategy for GIST treatment.

Evaluation of the bonding strength of dental zirconia with veneering porcelains

The effect of thermo-cycling treatment on the bond strength and flexural strength of porcelain veneered zirconia was evaluated. After thermo-cycling treatment between 5 degrees C to 55 degrees C, porcelain-zirconia bond strength and zirconia flexural strength was not significantly affected. In the phase analyses using XRD after thermo-cycling treatment, both the experimental group and the control group showed only tetragonal phases. That is, the porcelain-zirconia bond strength and zirconia flexural strength were not affected by low temperature degradation. So low temperature aging treatment did not reduce the flexural strength and the effect of temperature applied to the aging treatment could beignorable.

Abstract 3873: Hedgehog signaling maintains gastric cancer stem cells and promotes chemotherapy resistance: results from laboratory and clinical studies

Introduction: Gastric cancers may harbor a small subset of cancer stem cells (CSCs) with the exclusive ability to self-renew and differentiate into heterogenous cell types. These CSCs may also contribute to chemotherapy resistance. The Hedgehog (HH) pathway is a key developmental pathway that can be subverted by CSCs during tumorigenesis. However in a recent randomized phase II trial of chemotherapy with or without the small molecule HH inhibitor vismodegib for advanced gastric cancers, the addition of vismodegib did not increase progression-free survival (PFS) or overall survival (OS). In this study, we examine the role of HH signaling in gastric CSC maintenance and chemotherapy resistance.

Methods and Results: Gastric cancer cell lines AGS, MKN-45, and NCI-N87 were grown as spheroids to enrich for CSCs. Spheroid cells were found to have upregulation of the putative gastric CSC marker CD44 along with HH pathway proteins Shh, Ptch1, Smo, and Gli1. Inhibition of the HH signaling using Smo shRNA or vismodegib decreased spheroid formation by 70.3-78.4% or 66.9-70.8%, respectively, and attentuated another CSC phenotype, single cell colony formation, by 66.9-78.4%. Transformation phenotypes such as migration, invasion, and anchorage-independent colony formation were also inhibited in gastric CSCs by 50.2-65.6%, 57.4-66.3%, and 3.8-4.6 fold, respectively. CD44(+) gastric CSCs from all 3 cell lines were resistant to 5-fluorouracil or cisplatin chemotherapy, and this resistance was reversed with the addition of Smo shRNA or vismodegib. The combination of Smo shRNA and cisplatin synergistically blocked the growth of MKN-45 xenografts, and treated tumors demonstrated a 1.8-2.6 fold increase in tumor cell apoptosis compared to tumors treated with cisplatin alone. Clinical tumor samples from the phase II vismodegib trial were analyzed for CD44 expression (as a surrogate to levels of CSCs). In the chemotherapy alone group, high CD44 expression was associated with worse PFS and OS. However in the chemotherapy with vismodegib group, high CD44 expression was associated with improved PFS and OS. For two patients in the vismodegib arm of the study who had a complete response, CD44 levels were 6.1-fold higher than the other patients in the group (p=0.001).

Conclusions: HH signaling is required to maintain gastric CSC phenotypes such as spheroid formation and colony formation from single cells as well malignant transformation phenotypes such as migration, invasion, and anchorage-independent growth. Gastric CSCs are resistant to chemotherapy compared to unselected cells, and HH inhibition can reverse this resistance. Given gastric cancer is a heterogeneous disease, the strategy of combining chemotherapy with HH inhibition may only be effective in a subset of gastric cancer patients with high levels of CD44(+) gastric CSCs.

Citation Format: Changhwan Yoon, Do Joong Park, Benjamin Schmidt, Nicholas J. Thomas, Hae-June Lee, Teresa S. Kim, Yelena Y. Janjigian, Deirdre J. Cohen, Sam S. Yoon. Hedgehog signaling maintains gastric cancer stem cells and promotes chemotherapy resistance: results from laboratory and clinical studies. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3873. doi:10.1158/1538-7445.AM2014-3873

Comparison and correlation analysis of different Swine breeds meat quality

This study was performed to determine the influence of pig breed and gender on the ultimate pH and physicochemical properties of pork. The correlations between pH and pork quality traits directly related to carcass grade, and consumer’s preference were also evaluated. The pH and meat grading scores for cold carcasses of 215 purebred pigs (Duroc, Landrace, and Yorkshire) from four different farms were obtained. Meat quality parameters of the pork loin were analyzed. Duroc and female animals were more affected compared to other breeds and male pigs. Duroc animals had the highest ultimate pH, carcass back fat thickness, marbling scores, yellowness, and fat content (p<0.05). Landrace pigs had the highest color lightness and cooking loss values (p<0.05). Among all trait parameters, marbling scores showed the highest significant differences when evaluating the impact of breed and gender on meat quality characteristics (p<0.001). Ultimate pH was positively correlated with carcass weight (0.20), back fat thickness (0.19), marbling score (0.17), and color score (0.16) while negatively correlated with cooking loss (−0.24) and shear force (−0.20). Therefore, pork samples with lower ultimate pH had lower cooking loss, higher lightness, and higher shear force values irrespective of breed.

Pulmonary tuberculosis among patients hospitalised with community-acquired pneumonia in a tuberculosis-prevalent area

SETTING

A suburban teaching hospital in a tuberculosis (TB) prevalent area.

OBJECTIVES

To evaluate the proportion of pulmonary TB among patients hospitalised with suspected community-acquired pneumonia (CAP), and to develop a diagnostic index for identifying TB among these patients.

DESIGN

TB cases confirmed using 1) sputum culture, or 2) both sputum acid-fast bacilli smear and polymerase chain reaction for Mycobacterium tuberculosis, were compared with non-tuberculous CAP by demographic, clinical, laboratory and radiographic information. Using multiple logistic regression analysis, risk factors for TB were identified. A diagnostic index was developed by summing up their simplified regression coefficients. Its performance was checked using c-statistic.

RESULTS

TB was the second leading cause of CAP (37/528, 7.0%). Risk factors were initial symptoms >7 days, serum albumin <3.5 g/dl, cavitary/nodular infiltrates and upper lobe involvement (1 point for each). The c-statistic of the index was 0.856 (95%CI 0.789-0.923), and for bootstrapping samples of 1000 repetitions it was 0.856 (95%CI 0.791-0.921). For scores ≥2, sensitivity and specificity were respectively 81.1% and 75.8%.

CONCLUSION

TB is one of the leading causes of CAP in TB-prevalent areas. Our diagnostic index may help clinicians identify TB immediately from CAP and initiate appropriate isolation and optimal treatment.

CD44 expression denotes a subpopulation of gastric cancer cells in which Hedgehog signaling promotes chemotherapy resistance

PURPOSE

Gastric cancers may harbor a subset of cells with cancer stem cell (CSC) properties, including chemotherapy resistance, and CD44 is a gastric CSC marker. The Hedgehog (HH) pathway is a key developmental pathway that can be subverted by CSCs during tumorigenesis. Here, we examine the role of HH signaling in CD44(+) gastric cancer cells.

EXPERIMENTAL DESIGN

Gastric cancer cell lines, tumor xenografts, and patient tumors were examined.

RESULTS

Gastric cancer cell lines AGS, MKN-45, and NCI-N87 grown as spheroids or sorted for CD44(+) were found to have upregulation of HH pathway proteins. HH inhibition using Smoothened (Smo) shRNA or vismodegib (VIS) decreased spheroid formation and colony formation. CD44(+) cells, compared with unselected cells, were also resistant to 5-fluorouracil and cisplatin chemotherapy, and this resistance was reversed in vitro and in xenografts with Smo shRNA or VIS. CD44(+) cells also had significantly more migration, invasion, and anchorage-independent growth, and these properties could all be blocked with HH inhibition. Clinical tumor samples from a phase II trial of chemotherapy with or without VIS for advanced gastric cancer were analyzed for CD44 expression. In the chemotherapy alone group, high CD44 expression was associated with decreased survival, whereas in the chemotherapy plus VIS group, high CD44 expression was associated with improved survival.

CONCLUSIONS

HH signaling maintains CSC phenotypes and malignant transformation phenotypes in CD44(+) gastric cancer cells, and HH inhibition can reverse chemotherapy resistance in CD44(+) cells. Gastric cancer is a heterogeneous disease, and the strategy of combining chemotherapy with HH inhibition may only be effective in tumors with high CD44 levels.

A review of MR spectroscopy studies of pediatric bipolar disorder

Pediatric bipolar disorder is a severe mental illness whose pathophysiology is poorly understood and for which there is an urgent need for improved diagnosis and treatment. MR spectroscopy is a neuroimaging method capable of in vivo measurement of neurochemicals relevant to bipolar disorder neurobiology. MR spectroscopy studies of adult bipolar disorder provide consistent evidence for alterations in the glutamate system and mitochondrial function. In bipolar disorder, these 2 phenomena may be linked because 85% of glucose in the brain is consumed by glutamatergic neurotransmission and the conversion of glutamate to glutamine. The purpose of this article is to review the MR spectroscopic imaging literature in pediatric bipolar disorder, at-risk samples, and severe mood dysregulation, with a focus on the published findings that are relevant to glutamatergic and mitochondrial functioning. Potential directions for future MR spectroscopy studies of the glutamate system and mitochondrial dysfunction in pediatric bipolar disorder are discussed.

Outbreak among healthy newborns due to a new variant of USA300-related meticillin-resistant Staphylococcus aureus

BACKGROUND

The prevalence of community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) is increasing throughout the world and is an important cause of skin and soft tissue infection (SSTI) in children and neonates.

AIM

To describe the successful control of an outbreak caused by a new strain of CA-MRSA in a newborn nursery.

METHODS

The investigation of the outbreak in July 2012 is reported with the control measures taken. Molecular typing of the MRSA isolates was performed.

FINDINGS

An outbreak of SSTI caused by CA-MRSA occurred in a newborn nursery. Six neonates were infected in a one-month period [infection rate: 8.5% (6/71)]. A new variant of CA-MRSA was responsible, which was characterized as USA300-related, Panton-Valentine Leucocidin (PVL) positive, arginine catabolic mobile element (ACME) negative, sequence type 8 (ST8), staphylococcal cassette chromosome mec (SCCmec) type IVa, agr type I and spa type t008. The outbreak among term neonates followed a rapid transmission pattern and was successfully controlled by implementing various outbreak control measures, including universal chlorhexidine bathing.

CONCLUSION

This is the first report of a hospital outbreak caused by a USA300-related CA-MRSA clone in Korea. Early recognition and reinforcement of infection control measures are important in decreasing transmission of CA-MRSA in a hospital setting.

Increased KIT inhibition enhances therapeutic efficacy in gastrointestinal stromal tumor

PURPOSE

Gastrointestinal stromal tumor (GIST) is the most common human sarcoma and a model of targeted molecular therapy. GIST depends on oncogenic KIT signaling and responds to the tyrosine kinase inhibitor imatinib. However, imatinib is rarely curative. We hypothesized that PLX3397, which inhibits KIT and colony-stimulating-factor-1 receptor (CSF1R), would be more efficacious than imatinib in GIST by also depleting tumor-associated macrophages, which are generally thought to support tumor growth.

EXPERIMENTAL DESIGN

We treated Kit(V558del/+) mice that develop GIST or mice with subcutaneous human GIST xenografts with imatinib or PLX3397 and analyzed tumor weight, cellular composition, histology, molecular signaling, and fibrosis. In vitro assays on human GIST cell lines were also performed.

RESULTS

PLX3397 was more effective than imatinib in reducing tumor weight and cellularity in both Kit(V558del)(/+) murine GIST and human GIST xenografts. The superiority of PLX3397 did not depend on depletion of tumor-associated macrophages, because adding CSF1R inhibition did not improve the effects of imatinib. Instead, PLX3397 was a more potent KIT inhibitor than imatinib in vitro. PLX3397 therapy also induced substantial intratumoral fibrosis, which impaired the subsequent delivery of small molecules.

CONCLUSIONS

PLX3397 therapy has greater efficacy than imatinib in preclinical GIST models and warrants study in patients with GIST. The resultant intratumoral fibrosis may represent one of the barriers to achieving complete tumor eradication.