ZL-1211 Exhibits Robust Antitumor Activity by Enhancing ADCC and Activating NK Cell-mediated Inflammation in CLDN18.2-High and -Low Expressing Gastric Cancer Models

CLDN18.2 (Claudin18.2)-targeting therapeutic antibodies have shown promising clinical efficacy in approximately 30% of gastric cancers expressing high levels of CLDN18.2 and less pronounced activity in low expressing malignancies. Here, we report that ZL-1211 is a mAb targeting CLDN18.2 engineered to promote enhanced antibody-dependent cellular cytotoxicity (ADCC) with the goal of achieving more potent activity in a wider spectrum of high- and low-CLDN18.2 expressing tumors. ZL-1211 demonstrated more robust in vitro ADCC activity than clinical benchmark not only in CLDN18.2-high but also CLDN18.2-low expressing gastric tumor cell lines. Greater antitumor efficacy was also observed in mouse xenograft models. Natural killer (NK) cell played critical roles in ZL-1211 efficacy and NK-cell depletion abrogated ZL-1211-mediated ADCC activity in vitro. ZL-1211 efficacy in vivo was also dependent on the presence of an NK compartment. Strikingly, NK cells strongly induced an inflammatory response in response to ZL-1211 treatment, including increased IFNγ, TNFα, and IL6 production, and were recruited into tumor microenvironment in patient-derived gastric tumors expressing CLDN18.2 upon ZL-1211 treatment to lyse the tumor cells. Taken together, our data suggest that ZL-1211 more effectively targets CLDN18.2-high gastric cancers as well as -low expressing malignancies that may not be eligible for treatment with the leading clinical benchmark by inducing enhanced ADCC response and activating NK cells with robust inflammation to enhance antitumor efficacy. Clinical activity of ZL-1211 is currently under evaluation in a phase I clinical trial (NCT05065710).

Significance

ZL-1211, anti-CLDN18.2 therapeutic antibody can target CLDN18.2-high as well as -low gastric cancers that may not be eligible for treatment with clinical benchmark. ZL-1211 treatment induces NK-cell activation with robust inflammation to further activate antitumor immunity in tumor microenvironment.

Abstract 621: ZL-1211 exhibits robust anti-tumor activity by enhancing ADCC and activating innate and adaptive immunity in CLDN18.2-high and -low expressing gastric cancer models

CLDN18.2 (Claudin18.2)-targeting therapeutic antibodies have shown promising clinical efficacy in ~30% of gastric cancers expressing high levels of CLDN18.2 and less pronounced activity in the majority of low expressing malignancies. ZL-1211 is a monoclonal antibody targeting CLDN18.2 engineered to promote enhanced ADCC with the goal of achieving more potent activity in a wider spectrum of high- and low-CLDN18.2 expressing tumors than the leading clinical benchmark. To further assess the potency of ZL-1211, we utilized a panel of gastric tumor cell lines that endogenously express CLDN18.2 and more accurately reflect target levels in human gastric tumors than engineered overexpressing models. ZL-1211 demonstrated more robust in vitro ADCC activity than clinical benchmark not only in CLDN18.2-high but also -low expressing gastric cell lines. Greater anti-tumor efficacy was also observed in mouse xenograft models with CLDN18.2-high, -medium, and low-expressing gastric cell lines in response to treatment with ZL-1211 compared to the clinical benchmark. NK cell depletion abrogated ZL-1211-mediated ADCC activity in vitro. ZL-1211 efficacy in vivo was also dependent on the presence of an NK compartment, as CLDN18.2-expressing gastric tumors grown in Balb/c nude with an intact NK function were sensitive to ZL-1211 treatment, while NOD-SCID with partially competent NK activity exhibited minimal response, and NCG without NK cells did not display any evidence of in vivo efficacy. Strikingly, NK cells strongly induced an inflammatory response in response to ZL-1211 treatment, including increased IFNγ, TNFα, and IL-6 production. Interestingly, ZL-1211 treatment led to NK cell and monocyte stimulation and enhanced CD8+ T cell activation, suggesting a mechanism of action that not only involves innate but also adaptive immunity. Taken together, our data suggest that ZL-1211 more effectively targets CLDN18.2-high gastric cancers as well as -low expressing malignancies that are not eligible for treatment with the leading clinical benchmark by inducing a robust ADCC response and activating innate and adaptive immunity to enhance anti-tumor efficacy. Clinical activity of ZL-1211 is currently under evaluation in a Phase I clinical trial (NCT05065710).

Citation Format: Hiroyasu Konno, Tracey Lin, Bee-Chun Sun, Renyi Wu, Christopher Szeto, David Bellovin, Karl Hsu, Omar Kabbarah. ZL-1211 exhibits robust anti-tumor activity by enhancing ADCC and activating innate and adaptive immunity in CLDN18.2-high and -low expressing gastric cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 621.

Efficacy of cardiac rehabilitation with motion assistance from wearable cyborg hybrid assistive limb in patients with chronic heart failure: a randomized controlled trial

Background

Recent Cochrane Systematic Review suggested that the participation in cardiac rehabilitation is associated with approximately 20% lower cardiovascular mortality and morbidity. Exercise therapy is the key component of cardiac rehabilitation programs. In recent years, innovative technologies have been introduced into the field of rehabilitation, and a typical example is the wearable cyborg Hybrid Assistive Limb (HAL). The wearable cyborg HAL provides motion assistance based on detection of bioelectrical signals on the skin surface when muscle forces are generated. The lumbar-type HAL is expected to expand the therapeutic options for severe cardiac patients who have difficulty in performing usual cardiac rehabilitation programs, such as bicycle pedaling or walking.

Purpose

We aim to compare the efficacy of exercise therapy performed with motion assistance from a lumbar-type HAL versus conventional training (sit-to-stand exercise without HAL) in patients with chronic heart failure.

Methods

This clinical trial is a randomized, non-blinded, and controlled study. Twenty-eight heart failure patients (73.1±13.8 years) who have difficulty in walking at the usual walking speed of healthy subjects were randomly assigned to 2 groups (HAL group or control group) with a 1:1 allocation ratio and performed sit-to stand exercise either with HAL or without HAL for 5 to 30 minutes once a day, and 6 to 10 days during the study period. The brain natriuretic peptide (BNP), isometric knee extensor strength, standing ability (30-seconds chair-stand test: CS-30), short physical performance battery (SPPB) and 6-minute walking distance (6MWD) were measured before and after the completion of cardiac rehabilitation. Cardiac events such as death, re-hospitalization, myocardial infarction and worsening of angina pectoris and heart failure during 1 year after discharge were evaluated.

Results

There was no significant difference in the number of days of exercise therapy between the two groups. BNP, SPPB and 6MWD were improved in both groups. In the HAL group, the isometric knee extensor strength (0.29±0.11 vs 0.35±0.11 kgf/kg, p=0.003) significantly improved and CS-30 (5.5±5.1 vs 8.2±5.3, p=0.054) tended to improve. However, in the control group, either the isometric knee extensor strength (0.35±0.11 vs 0.36±0.14 kgf/kg, p=0.424) or CS-30 (6.0±4.3 vs 9.2±6.2, p=0.075) did not significantly change. HAL group showed significantly more improvement in the isometric knee extensor strength than control group (p=0.045). Cardiac events occurred in 20% in the HAL group and 43% in the control group.

Conclusion

The improvement in isometric knee extensor strength with the assistance from lumbar-type HAL suggests that exercise therapy using this device may be useful in chronic heart failure patients with flail or sarcopenia, a strong poor prognostic factor in these patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (JSPS KAKENHI grant number JP17K09485) and funded by the ImPACT Program of the Council for Science, Technology and Innovation (Cabinet Office, Government of Japan) (grant number 2017-PM05-03-01).

Pro-inflammation Associated with a Gain-of-Function Mutation (R284S) in the Innate Immune Sensor STING

The cellular sensor stimulator of interferon genes (STING) initiates type I interferon (IFN) and cytokine production following association with cyclic dinucleotides (CDNs) generated from intracellular bacteria or via a cellular synthase, cGAS, after binding microbial or self-DNA. Although essential for protecting the host against infection, unscheduled STING signaling is now known to be responsible for a variety of autoinflammatory disorders. Here, we report a gain-of-function mutation in STING (R284S), isolated from a patient who did not require CDNs to augment activity and who manifested a constitutively active phenotype. Control of the Unc-51-like autophagy activating kinase 1 (ULK1) pathway, which has previously been shown to influence STING function, was potently able to suppress STING (R284S) activity to alleviate cytokine production. Our findings add to the growing list of inflammatory syndromes associated with spontaneous STING signaling and provide a therapeutic strategy for the treatment of STING-induced inflammatory disease.

Ovarian Cancer Cells Commonly Exhibit Defective STING Signaling Which Affects Sensitivity to Viral Oncolysis

Ovarian cancer is the sixth most prevalent cancer in women and the most lethal of the gynecologic malignancies. Treatments have comprised the use of immunotherapeutic agents as well as oncolytic viruses, with varying results for reasons that remain to be clarified. To better understand the mechanisms that may help predict treatment outcome, we have evaluated innate immune signaling in select ovarian cancer cell lines, governed by the Stimulator of Interferon Genes (STING), which controls self or viral DNA-triggered cytokine production. Our results indicate that STING-dependent signaling is habitually defective in majority of ovarian cancer cells examined, frequently through the suppression of STING and/or the cyclic dinucleotide (CDN) enzyme Cyclic GMP-AMP synthase (cGAS) expression, by epigenetic processes. However, STING-independent, dsRNA-activated innate immune cytokine production, which require RIG-I/MDA5, were largely unaffected. Such defects enabled ovarian cancer cells to avoid DNA damage-mediated cytokine production, which would alert the immunosurveillance system. Loss of STING signaling also rendered ovarian cancer cells highly susceptible to viral oncolytic γ34.5 deleted-HSV1 (Herpes simplex virus) infection in vitro and in vivo. IMPLICATIONS: STING signaling evaluation in tumors may help predict disease outcome and possibly dictate the efficacy of oncoviral and other types of cancer therapies.

Biological and Biochemical Roles of Two Distinct Cyclic Dimeric Adenosine 3',5'-Monophosphate- Associated Phosphodiesterases in Streptococcus mutans

Cyclic dimeric adenosine 3′,5′-monophosphate (c-di-AMP), a recently identified secondary messenger in bacteria, plays a role in several bacterial processes, including biofilm formation. It is enzymatically produced by diadenylate cyclase and cleaved by c-di-AMP phosphodiesterase. c-di-AMP is believed to be essential for the viability of bacterial cells that produce it. In the current study, the biochemical and biological roles of GdpP (SMU_2140c) and DhhP (SMU_1297), two distinct Streptococcus mutans phosphodiesterases involved in the pathway producing AMP from c-di-AMP, were investigated. Liquid chromatography-tandem mass spectrometry revealed that c-di-AMP was degraded to phosphoadenylyl adenosine (pApA) by truncated recombinant GdpP, and pApA was cleaved by recombinant DhhP to yield AMP. In-frame deletion mutants lacking the dhhP gene (ΔdhhP) and both the gdpP and dhhP genes (ΔgdpPΔdhhP) displayed significantly more biofilm formation than the wild-type and a mutant strain lacking the gdpP gene (ΔgdpP; p < 0.01). Furthermore, biofilm formation was restored to the level of the wild type strain upon complementation with dhhP. Optical and electron microscopy observations revealed that ΔdhhP and ΔgdpPΔdhhP mutants self-aggregated into large cell clumps, correlated with increased biofilm formation, but cell clumps were not observed in cultures of wild-type, ΔgdpP, or strains complemented with gdpP and dhhP. Thus, deletion of dhhP presumably leads to the formation of bacterial cell aggregates and a subsequent increase in biofilm production.

Suppression of STING signaling through epigenetic silencing and missense mutation impedes DNA damage mediated cytokine production

The production of cytokines in response to DNA damage events may be an important host defense response to help prevent the escape of pre-cancerous cells. The innate immune pathways involved in these events are known to be regulated by cellular molecules such as STING (stimulator of interferon genes), which controls type I interferon and pro-inflammatory cytokine production in response to the presence of microbial DNA or cytosolic DNA that has escaped from the nucleus. STING signaling has been shown to be defective in a variety of cancers, such as colon cancer and melanoma, actions which may enable damaged cells to escape the immunosurveillance system. Here, we report through examination of databases that STING signaling may be commonly suppressed in a greater variety of tumors due to loss-of-function mutation or epigenetic silencing of the STING/cGAS promoter regions. In comparison, RNA activated innate immune pathways controlled by RIG-I/MDA5 were significantly less affected. Examination of reported missense STING variants confirmed that many exhibited a loss of function phenotype and could not activate cytokine production following exposure to cytosolic DNA or DNA-damage events. Our data implies that the STING signaling pathway may be recurrently suppressed by a number of mechanisms in a considerable variety of malignant disease and be a requirement for cellular transformation.

Ubiquitination of STING at lysine 224 controls IRF3 activation

Cytosolic DNA species derived from invading microbes or leaked from the nuclear or mitochondrial compartments of the cell can trigger the induction of host defense genes by activating the endoplasmic reticulum-associated protein STING (stimulator of interferon genes). Using a mass spectrometry-based approach, we show that after association with cyclic dinucleotides, delivery of Tank-binding kinase 1 to interferon regulatory factors (IRFs), such as IRF3, relies on K63-linked ubiquitination of K224 on STING. Blocking K224 ubiquitination specifically prevented IRF3 but not nuclear factor κB activation, additionally indicating that STING trafficking is not required to stimulate the latter signaling pathway. By carrying out a limited small interfering RNA screen, we have identified MUL1 (mitochondrial E3 ubiquitin protein ligase 1) as an E3 ligase that catalyzes the ubiquitination of STING on K224. These data demonstrate the critical role of K224 ubiquitination in STING function and provide molecular insight into the mechanisms governing host defense responses.

Impact of hospital volume on risk-adjusted mortality following oesophagectomy in Japan

Background

Previous studies have reported that patients undergoing oesophagectomy in high-volume hospitals experience lower mortality rates. However, there has been ongoing discussion regarding the validity of evidence for this association. The purpose of this study was to investigate the relationship between hospital volume and risk-adjusted mortality following oesophagectomy in Japan, using a nationwide web-based database.

Methods

The study included patients registered in the database as having undergone oesophagectomy with reconstruction between 2011 and 2013. Outcome measures were 30-day and operative mortality rates. Logistic regression analysis was used to adjust for hospital volume, surgeon volume and risk factors for mortality after oesophagectomy.

Results

A total of 16 556 oesophagectomies at 988 hospitals were included; the overall unadjusted 30-day and operative mortality rates were 1·1 and 3·0 per cent respectively. The unadjusted operative mortality rate in hospitals performing fewer than ten procedures per year (5·1 per cent) was more than three times higher than that in hospitals conducting 30 or more procedures annually (1·5 per cent). Multivariable models indicated that hospital volume had a significant effect on 30-day (odds ratio 0·88 per 10-patient increase; P = 0·012) and operative (odds ratio 0·86 per 10-patient increase; P &lt; 0·001) mortality.

Conclusion

In Japan, high-volume hospitals had lower risk-adjusted 30-day and operative mortality rates following oesophagectomy compared with low-volume hospitals.

Recurrent Loss of STING Signaling in Melanoma Correlates with Susceptibility to Viral Oncolysis

The innate immunoregulator STING stimulates cytokine production in response to the presence of cytosolic DNA, which can arise following DNA damage. Extrinsic STING signaling is also needed for antigen-presenting cells to stimulate antitumor T-cell immunity. Here, we show that STING signaling is recurrently suppressed in melanoma cells, where this event may enable immune escape after DNA damage. Mechanistically, STING signaling was suppressed most frequently by epigenetic silencing of either STING or the cyclic GMP-AMP synthase, which generates STING-activating cyclic dinucleotides after binding cytosolic DNA species. Loss of STING function rendered melanoma cells unable to produce type I IFN and other immune cytokines after exposure to cytosolic DNA species. Consequently, such cells were highly susceptible to infection with DNA viruses including HSV1, a variant of which is being developed presently as a therapeutic oncolytic virus [talimogene laherparepvec (T-VEC)]. Our findings provide insight into the basis for susceptibility to viral oncolysis by agents such as HSV1. Cancer Res; 76(22); 6747-59. ©2016 AACR.

An autopsied case of neuromyelitis optica with a large cavitary cerebral lesion

We report a case of neuromyelitis optica (NMO) with a large cerebral lesion. The patient had an episode of fever and consciousness disturbance with a tumefactive frontal white matter lesion at age 43, and then repeated bilateral optic neuritis and transverse myelitis until she died at age 63. Histopathological examinations revealed that marked tissue destruction, cavities and inflammatory changes typical of NMO were seen in the cerebrum as well as the optic nerves and spinal cord. This is the first autopsied case of NMO with a tumefactive cerebral lesion that later became cavitary.

Activation of STING requires palmitoylation at the Golgi

Stimulator of interferon genes (STING) is essential for the type I interferon response against DNA pathogens. In response to the presence of DNA and/or cyclic dinucleotides, STING translocates from the endoplasmic reticulum to perinuclear compartments. However, the role of this subcellular translocation remains poorly defined. Here we show that palmitoylation of STING at the Golgi is essential for activation of STING. Treatment with palmitoylation inhibitor 2-bromopalmitate (2-BP) suppresses palmitoylation of STING and abolishes the type I interferon response. Mutation of two membrane-proximal Cys residues (Cys88/91) suppresses palmitoylation, and this STING mutant cannot induce STING-dependent host defense genes. STING variants that constitutively induce the type I interferon response were found in patients with autoimmune diseases. The response elicited by these STING variants is effectively inhibited by 2-BP or an introduction of Cys88/91Ser mutation. Our results may lead to new treatments for cytosolic DNA-triggered autoinflammatory diseases.

STING is essential for the type I interferon immune response to foreign DNA. Here, the authors show that palmitoylation of STING at the Golgi is required for activating downstream signalling, and increased Golgi localization of certain STING variants may cause autoimmune disease in some cases.

Deregulation of STING Signaling in Colorectal Carcinoma Constrains DNA Damage Responses and Correlates With Tumorigenesis

Stimulator of interferon genes (STING) has been shown to be critical for controlling antiviral responses as well as anti-tumor adaptive immunity, but little is known regarding its regulation in human tumors. Here, we report that STING signaling is recurrently suppressed in a wide variety of cancers, including colorectal carcinoma. Loss of STING signaling impeded DNA damage responses accountable for generating key cytokines that facilitate tissue repair and anti-tumor T cell priming, such as type I interferons (IFNs). Correspondingly, defective STING function was also highly predictive of effectual DNA-virus-mediated oncolytic activity. Thus, impaired STING responses may enable damaged cells to evade host immunosurveillance processes, although they provide a critical prognostic measurement that could help predict the outcome of effective oncoviral therapy.

Loss of Tifab, a del(5q) MDS gene, alters hematopoiesis through derepression of Toll-like receptor-TRAF6 signaling

Varney et al. report that that deletion of the TRAF-interacting protein TIFAB contributes to an MDS-like phenotype in mice by up-regulating TRAF6 and contributing to hematopoietic dysfunction.

TRAF-interacting protein with forkhead-associated domain B (TIFAB) is a haploinsufficient gene in del(5q) myelodysplastic syndrome (MDS). Deletion of Tifab results in progressive bone marrow (BM) and blood defects, including skewed hematopoietic stem/progenitor cell (HSPC) proportions and altered myeloid differentiation. A subset of mice transplanted with Tifab knockout (KO) HSPCs develop a BM failure with neutrophil dysplasia and cytopenia. In competitive transplants, Tifab KO HSPCs are out-competed by wild-type (WT) cells, suggesting a cell-intrinsic defect. Gene expression analysis of Tifab KO HSPCs identified dysregulation of immune-related signatures, and hypersensitivity to TLR4 stimulation. TIFAB forms a complex with TRAF6, a mediator of immune signaling, and reduces TRAF6 protein stability by a lysosome-dependent mechanism. In contrast, TIFAB loss increases TRAF6 protein and the dynamic range of TLR4 signaling, contributing to ineffective hematopoiesis. Moreover, combined deletion of TIFAB and miR-146a, two genes associated with del(5q) MDS/AML, results in a cooperative increase in TRAF6 expression and hematopoietic dysfunction. Re-expression of TIFAB in del(5q) MDS/AML cells results in attenuated TLR4 signaling and reduced viability. These findings underscore the importance of efficient regulation of innate immune/TRAF6 signaling within HSPCs by TIFAB, and its cooperation with miR-146a as it relates to the pathogenesis of hematopoietic malignancies, such as del(5q) MDS/AML.

Catalytic subunits of the phosphatase calcineurin interact with NF-κB-inducing kinase (NIK) and attenuate NIK-dependent gene expression

Nuclear factor (NF)-κB-inducing kinase (NIK) is a serine/threonine kinase that activates NF-κB pathways, thereby regulating a wide variety of immune systems. Aberrant NIK activation causes tumor malignancy, suggesting a requirement for precise regulation of NIK activity. To explore novel interacting proteins of NIK, we performed in vitro virus screening and identified the catalytic subunit Aα isoform of serine/threonine phosphatase calcineurin (CnAα) as a novel NIK-interacting protein. The interaction of NIK with CnAα in living cells was confirmed by co-immunoprecipitation. Calcineurin catalytic subunit Aβ isoform (CnAβ) also bound to NIK. Experiments using domain deletion mutants suggested that CnAα and CnAβ interact with both the kinase domain and C-terminal region of NIK. Moreover, the phosphatase domain of CnAα is responsible for the interaction with NIK. Intriguingly, we found that TRAF3, a critical regulator of NIK activity, also binds to CnAα and CnAβ. Depletion of CnAα and CnAβ significantly enhanced lymphotoxin-β receptor (LtβR)-mediated expression of the NIK-dependent gene Spi-B and activation of RelA and RelB, suggesting that CnAα and CnAβ attenuate NF-κB activation mediated by LtβR-NIK signaling. Overall, these findings suggest a possible role of CnAα and CnAβ in modifying NIK functions.

The STING controlled cytosolic-DNA activated innate immune pathway and microbial disease

The innate immune system is critically important for the primary sensing of invading pathogens. Over the past decade, the cellular sensors important for recognizing microbial entry into the host cell have been largely elucidated. These sensors, some of which are evolutionarily conserved, include the Toll-like receptor (TLR) and RIG-I-like helicase family (RLH) pathway that can recognize bacterial and viral non-self nucleic acid. In addition, a cellular sensor referred to as STING (for stimulator of interferon genes) has been shown to be critical for triggering host defense countermeasures, including stimulation of the adaptive immune response, following the detection of cytosolic DNA species. The STING pathway has now been shown to be critical for activating innate immune gene transcription in response to infection by DNA pathogens such as herpes simplex virus 1 (HSV1) as well as retroviruses. In addition, it is clear that chronic STING activation can also cause autoinflammatory disease manifested by self-DNA. Here we review recent developments in our understanding of STING function, including importance in the control of microbial disease.

Inflammation-driven carcinogenesis is mediated through STING

Chronic stimulation of innate immune pathways by microbial agents or damaged tissue is known to promote inflammation-driven tumorigenesis by mechanisms that are not well understood. Here we demonstrate that mutagenic 7,12-dimethylbenz(a)anthracene (DMBA), cisplatin and etoposide induce nuclear DNA leakage into the cytosol that intrinsically activates stimulator of interferon genes (STING)-dependent cytokine production. Inflammatory cytokine levels are subsequently augmented in a STING-dependent extrinsic manner by infiltrating phagocytes purging dying cells. Consequently, STING(-/-) mice, or wild-type mice adoptively transferred with STING(-/-) bone marrow, are almost completely resistant to DMBA-induced skin carcinogenesis compared with their wild-type counterparts. Our data establish a role for STING in the control of cancer, shed significant insight into the causes of inflammation-driven carcinogenesis and may provide a basis for therapeutic strategies to help prevent malignant disease.

Cyclic dinucleotides trigger ULK1 (ATG1) phosphorylation of STING to prevent sustained innate immune signaling

Activation of the stimulator of interferon genes (STING) pathway by microbial or self-DNA, as well as cyclic dinucleotides (CDNs), results in the induction of numerous genes that suppress pathogen replication and facilitate adaptive immunity. However, sustained gene transcription is rigidly prevented to avoid lethal STING-dependent proinflammatory disease by mechanisms that remain unknown. We demonstrate here that, after autophagy-dependent STING delivery of TANK-binding kinase 1 (TBK1) to endosomal/lysosomal compartments and activation of transcription factors interferon regulatory factor 3 (IRF3) and NF-κB, STING is subsequently phosphorylated by serine/threonine UNC-51-like kinase (ULK1/ATG1), and IRF3 function is suppressed. ULK1 activation occurred following disassociation from its repressor AMP activated protein kinase (AMPK) and was elicited by CDNs generated by the cGAMP synthase, cGAS. Thus, although CDNs may initially facilitate STING function, they subsequently trigger negative-feedback control of STING activity, thus preventing the persistent transcription of innate immune genes.

Loss of STING eliminates proinflammatory gene induction in TrexI-/- deficient mice. (P4091)

Patients defective in the 3’ repair exonuclease 1 (Trex1) suffer from Aicardi-Goutieres Syndrome (AGS) which instigates lethal encephalitis characterized by high levels of type I IFN production being present in the cerebrospinal fluid. Trex1 deficient mice exhibit a median life span of approximately 9 weeks since as yet uncharacterized self-DNA, presumably normally digested by Trex1, activates intracellular DNA sensors which triggers cytokine production and causes lethal inflammatory aggravated myocarditis. STING is essential for triggering cytoplasmic DNA-dependent innate immune signaling that comprises the production of type I IFN. Loss of TREX1 was observed to augment ssDNA and dsDNA-mediated induction of type I IFN in a STING-dependent manner. The replication of HSV1 was greatly reduced in hTERT-BJ1 or MEF lacking TREX1 due to elevated STING-dependent cytokine production. Loss of STING was observed to significantly extend the lifespan of Trex1-/- due to prevention of myocarditis. Microarray analysis showed dramatically reduced levels of proinflammatory genes in the hearts of Sting-/- Trex1-/-, Sting-/+ Trex1-/- compared to Trex1-/- mice. Anti-nuclear autoantibody (ANA) observed to be highly prevalent in the sera of Trex1-/- mice was almost completely absent in the sera of Sting-/- Trex1-/- mice. These data indicates that STING is responsible for pro-inflammatory gene induction in Trex1 deficient mice and plausibly may be involved in AGS.

STING recognition of cytoplasmic DNA instigates cellular defense (P1393)

How the cell recognizes cytosolic DNA including DNA based microbes to trigger host defense related gene activation remains to be fully resolved. Here, we demonstrate that STING (for Stimulator of Interferon Genes), an endoplasmic reticulum (ER) translocon associated transmembrane protein, acts to detect cytoplasmic DNA species. STING homodimers were able to complex with self (apoptotic, necrotic) or pathogen related ssDNA and dsDNA and were indispensible for HSV-1-mediated transcriptional activation of a wide array of innate immune and pro-inflammatory genes in addition to type I IFN. Our data indicates that STING instigates cytoplasmic DNA-mediated cellular defense gene transcription and facilitates adoptive responses that are required for protection of the host. In contrast, chronic STING activation may manifest inflammatory responses and possibly autoimmune disease triggered by self-DNA.

Abstract P6-04-17: The androgen metabolite-dependent growth in hormone receptor positive breast cancer as a novel aromatase inhibitor-resistance mechanism

Introduction: Aromatase inhibitors (AIs) have been reported to exert their anti-proliferative effects not only by reducing the production of estrogens but also by unmasking the inhibitory effect of androgens such as testosterone (TS) or dihydrotestosterone (DHT) in postmenopausal women with hormone receptor-positive breast cancer. The behavior of androgens in AI-resistance mechanisms is not sufficiently understood. 5α-androstane-3β,17β-diol (3β-diol) generated from DHT by 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD type 1: HSD3B1) has androgenic activity and substantial estrogenic activity, representing a potential mechanism of AI resistance.

Methods: To investigate these issues, ERE-GFP-transfected MCF-7-E10 cells were cultured for 3 months under steroid-depleted, TS-supplemented conditions which is the similar as the AI treatment. Among the surviving cells, two stable variants that show ER activity depending on androgen metabolites were selected as AD-EDR (androgen metabolite-dependent and estrogen depletion-resistant) by monitoring GFP expression. Using these cell lines, we investigated the process of adaptation to androgen-abundant conditions and the role of androgens in AI-resistance mechanisms.

Results: AD-EDR cell lines showed increased growth and induction of estrogen-responsive genes rather than androgen-responsive genes by androgens or 3β-diol. Further analysis revealed increased expressions of HSD3B1 and reduced expression of androgen receptor (AR) in these cell lines. In parental MCF-7-E10 cells, ectopic expression of HSD3B1 or inhibition of AR resulted in adaptation to estrogen-deprived and androgen-abundant conditions. In coculture with stromal cells replicating the local estrogen production from androgen, AD-EDR cell lines showed AI resistance compared with parental MCF-7-E10 cells. Immunohistochemistry and real-time PCR analyses on 9 pairs of primary and recurrent tissue samples from AI-resistant breast cancer revealed the decrease of AR protein expression in all cases and increase of HSD3B1 mRNA expression in 5.

Conclusion: In the present study, we successfully cloned two stable variants that show ER activity depending on androgen metabolites. Investigation of these cell lines suggested that the increased function of 3β-HSD type 1 and reduced function of AR contribute to AI resistance by enhancing the androgen metabolite-dependent growth and reducing the inhibitory effect of androgens. Our data of clinical samples suggest that this mechanism also acts as an AI-resistance in clinical breast cancer in some cases.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-17.

Influence of age and gender on human lymphatic pumping pressure in the leg

Lymph transportation is controlled, at least in part, by the intrinsic pumping of lymphatic vessels. The objectives of this study were to evaluate the influences of age and gender on leg lymphatic pumping pressure. A total of 399 subjects between the ages of 20 and 91 years (199 males and 200 females) volunteered to participate in this study. Lymphatic pumping was measured in 798 legs of the 399 participants. Indocyanine green (ICG) fluorescence lymphography was performed, and the real-time fluorescence images of lymph propulsion were obtained in a sitting position using an infrared-light camera system. A custom-made transparent sphygmomanometer cuff was wrapped around the lower leg and connected to a standard mercury sphygmomanometer. The cuff was inflated, and then gradually deflated until the fluorescent dye exceeded the upper border of the cuff. Lymph pumping pressure was defined as the value of the cuff pressure when the dye exceeded the upper border of the cuff. There was a significant correlation between the leg lymphatic pumping and age: r = -0.34 (p < 0.0001). Comparison of lymphatic pumping between males and females indicated that the age-related decrease in lymphatic pumping pressure was more marked in females of postmenopausal age.

RANK signaling induces interferon-stimulated genes in the fetal thymic stroma

Medullary thymic epithelial cells (mTECs) are essential for thymic negative selection to prevent autoimmunity. Previous studies show that mTEC development is dependent on the signal transducers TRAF6 and NIK. However, the downstream target genes of signals controlled by these molecules remain unknown. We performed a microarray analysis on mRNAs down-regulated by deficiencies in TRAF6 or functional NIK in an in vitro organ culture of fetal thymic stromata (2DG-FTOC). An in silico analysis of transcription factor binding sites in plausible promoter regions of differentially expressed genes suggests that STAT1 is involved in TRAF6- and NIK-dependent gene expression. Indeed, the signal of RANK, a TNF receptor family member that activates TRAF6 and NIK, induces the activation of STAT1 in 2DG-FTOC. Moreover, RANK signaling induces the up-regulation of interferon (IFN)-stimulated gene (ISG) expression, suggesting that the RANKL-dependent activation of STAT1 up-regulates ISG expression. The RANKL-dependent expression levels of ISGs were reduced but not completely abolished in interferon α receptor 1-deficient (Ifnar1(-/-)) 2DG-FTOC. Our data suggest that RANK signaling induces ISG expression in both type I interferon-independent and interferon-dependent mechanisms.

TRAF6 establishes innate immune responses by activating NF-kappaB and IRF7 upon sensing cytosolic viral RNA and DNA

Background

In response to viral infection, the innate immune system recognizes viral nucleic acids and then induces production of proinflammatory cytokines and type I interferons (IFNs). Toll-like receptor 7 (TLR7) and TLR9 detect viral RNA and DNA, respectively, in endosomal compartments, leading to the activation of nuclear factor κB (NF-κB) and IFN regulatory factors (IRFs) in plasmacytoid dendritic cells. During such TLR signaling, TNF receptor-associated factor 6 (TRAF6) is essential for the activation of NF-κB and the production of type I IFN. In contrast, RIG-like helicases (RLHs), cytosolic RNA sensors, are indispensable for antiviral responses in conventional dendritic cells, macrophages, and fibroblasts. However, the contribution of TRAF6 to the detection of cytosolic viral nucleic acids has been controversial, and the involvement of TRAF6 in IRF activation has not been adequately addressed.

Principal Findings

Here we first show that TRAF6 plays a critical role in RLH signaling. The absence of TRAF6 resulted in enhanced viral replication and a significant reduction in the production of IL-6 and type I IFNs after infection with RNA virus. Activation of NF-κB and IRF7, but not that of IRF3, was significantly impaired during RLH signaling in the absence of TRAF6. TGFβ-activated kinase 1 (TAK1) and MEKK3, whose activation by TRAF6 during TLR signaling is involved in NF-κB activation, were not essential for RLH-mediated NF-κB activation. We also demonstrate that TRAF6-deficiency impaired cytosolic DNA-induced antiviral responses, and this impairment was due to defective activation of NF-κB and IRF7.

Conclusions/Significance

Thus, TRAF6 mediates antiviral responses triggered by cytosolic viral DNA and RNA in a way that differs from that associated with TLR signaling. Given its essential role in signaling by various receptors involved in the acquired immune system, TRAF6 represents a key molecule in innate and antigen-specific immune responses against viral infection.

Indocyanine green fluorescence angiography for intraoperative assessment of blood flow: a feasibility study

OBJECTIVE

To introduce our preliminary experience with indocyanine green (ICG) fluorescence angiography for the assessment of lower leg bypasses.

METHODS

1ml of 0.5% indocyanine green was intravenously injected in 9 patients with PAD who underwent paramalleolar artery bypass using saphenous vein grafts. A newly developed near-infrared camera system (PDE; Hamamatsu Photonics K.K. Hamamatsu, Japan) was used for this study.

RESULTS

ICG fluorescence angiography was performed without any adverse events. Fluorescence images of ICG angiography could be viewed as real-time images of the angiography in eight patients, while one patient underwent graft revision with the absence of fluorescence in ICG angiography.

CONCLUSION

ICG fluorescence angiography is clinically feasible and may help surgeons assess the quality of lower leg bypasses.

Multicenter phase II trial of combination chemotherapy with weekly paclitaxel and 5-fluorouracil for the treatment of advanced or recurrent gastric carcinoma

The aim of this study was to investigate the efficacy and safety of combination chemotherapy with weekly paclitaxel and 5-fluorouracil (5-FU) as first-line treatment in patients with advanced or recurrent gastric carcinoma. A total of 65 patients were treated with the following regimen, administered every 28 days; 5-FU 600 mg/m2 by 24-hour continuous infusion from days 1 through 5, and weekly paclitaxel 80 mg/m2 by 3-hour intravenous infusion on days 8, 14, and 21. A total of 272 cycles were conducted with a median of 4 (2-13) cycles per case. Out of 57 patients with measurable disease by RECIST criteria, there were 2 complete responses (3.5%), 20 partial responses (35.1%) and 25 cases with stable disease (43.9%). The overall response rate was 38.6% (95%CI: 26.0-51.2%). The median survival time and 1-year survival rates were 329 days and 47.4%, respectively. Both hematologic and non-hematologic toxicities were well tolerated.

Loss of aquaporin 4 in lesions of neuromyelitis optica: distinction from multiple sclerosis

Neuromyelitis optica (NMO) is an inflammatory and necrotizing disease clinically characterized by selective involvement of the optic nerves and spinal cord. There has been a long controversy as to whether NMO is a variant of multiple sclerosis (MS) or a distinct disease. Recently, an NMO-specific antibody (NMO-IgG) was found in the sera from patients with NMO, and its target antigen was identified as aquaporin 4 (AQP4) water channel protein, mainly expressed in astroglial foot processes. However, the pathogenetic role of the AQP4 in NMO remains unknown. We did an immunohistopathological study on the distribution of AQP4, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), activated complement C9neo and immunoglobulins in the spinal cord lesions and medulla oblongata of NMO (n = 12), MS (n = 6), brain and spinal infarction (n = 7) and normal control (n = 8). The most striking finding was that AQP4 immunoreactivity was lost in 60 out of a total of 67 acute and chronic NMO lesions (90%), but not in MS plaques. The extensive loss of AQP4 accompanied by decreased GFAP staining was evident, especially in the active perivascular lesions, where immunoglobulins and activated complements were deposited. Interestingly, in those NMO lesions, MBP-stained myelinated fibres were relatively preserved despite the loss of AQP4 and GFAP staining. The areas surrounding the lesions in NMO had enhanced expression of AQP4 and GFAP, which reflected reactive gliosis. In contrast, AQP4 immunoreactivity was well preserved and rather strongly stained in the demyelinating MS plaques, and infarcts were also stained for AQP4 from the very acute phase of necrosis to the chronic stage of astrogliosis. In normal controls, AQP4 was diffusely expressed in the entire tissue sections, but the staining in the spinal cord was stronger in the central grey matter than in the white matter. The present study demonstrated that the immunoreactivities of AQP4 and GFAP were consistently lost from the early stage of the lesions in NMO, notably in the perivascular regions with complement and immunoglobulin deposition. These features in NMO were distinct from those of MS and infarction as well as normal controls, and suggest that astrocytic impairment associated with the loss of AQP4 and humoral immunity may be important in the pathogenesis of NMO lesions.

TROY and LINGO-1 expression in astrocytes and macrophages/microglia in multiple sclerosis lesions

Nogo constitutes a family of neurite outgrowth inhibitors contributing to a failure of axonal regeneration in the adult central nervous system (CNS). Nogo-A is expressed exclusively on oligodendrocytes where Nogo-66 segment binds to Nogo receptor (NgR) expressed on neuronal axons. NgR signalling requires a coreceptor p75(NTR) or TROY in combination with an adaptor LINGO-1. To characterize the cell types expressing the NgR complex in the human CNS, we studied demyelinating lesions of multiple sclerosis (MS) brains by immunohistochemistry. TROY and LINGO-1 were identified in subpopulations of reactive astrocytes, macrophages/microglia and neurones but not in oligodendrocytes. TROY was up-regulated, whereas LINGO-1 was reduced in MS brains by Western blot. These results suggest that the ternary complex of NgR/TROY/LINGO-1 expressed on astrocytes, macrophages/microglia and neurones, by interacting with Nogo-A on oligodendrocytes, might modulate glial-neuronal interactions in demyelinating lesions of MS.

Intraoperative Monitoring of Penile and Buttock Blood Flow During Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

The purpose of this study was to assess the pelvic circulation during endovascular abdominal aortic aneurysm repair (EVAR) with a new monitoring system measuring penile and buttock blood flow.

METHODS

We measured penile brachial pressure index (PBI) during EVAR by pulse-volume-plethysmography (form PWV/ABItrade mark). We also measured bilateral gluteal tissue oxygen metabolism with near-infrared spectroscopy to provide a gluteal tissue oxygenation index (TOI). Twenty-two men who underwent aortouni-iliac stentgraft with crossover bypass for exclusion of abdominal aortic aneurysm were studied. Twelve patients underwent aorto-uni-common iliac artery stentgraft (CIA) and ten underwent aorto-uni-external iliac artery stentgraft (EIA).

RESULTS

In all patients, there was an immediate reduction in PBI during the EVAR procedure. After revascularization of the ipsilateral limb of the stent graft, the recovery of PBI was significantly less in EIA group. After the completion of crossover bypass, PBI in both groups recovered to the baseline values. In both groups there was a bilateral reduction in gluteal TOI during malperfusion of the internal iliac artery. After revascularization of ipsilateral limb of the stent graft, the ipsilateral TOI recovered to the baseline level in CIA patients, but recovery was incomplete in EIA patients. In contrast, contra-lateral TOI remained low in both groups after revascularization of ipsilateral limb of the stent graft. Only after completion of crossover bypass did the contra-lateral TOI recover to baseline level in both groups.

CONCLUSIONS

Both TOI at the buttocks and PBI are a sensitive reflection of pelvic haemodynamics. Penile blood flow and bilateral gluteal blood flow are supplied via different circulations and both should be monitored for full assessment of the pelvic circulation.

Association of interleukin-8 and plasminogen activator system in the progression of colorectal cancer

The aim of this study was to investigate the relationship of Interleukin-8 (IL-8) with vascular endothelial growth factor (VEGF) and plasminogen activator system (PA system) in the progression of colorectal cancer (CRC). In eighty-seven patients with CRC, the levels of IL-8, and VEGF as representative angiogenic factors and urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1), and PAI-2 as representative invasive factors were quantitatively assayed in tumor and adjacent normal tissues. The levels of IL-8, VEGF, and PA system factors in tumor tissues were all significantly higher than those in normal tissues. The IL-8 level was significantly associated with tumor size, depth of infiltration, Dukes stage, and liver metastasis, and also significantly correlated with the levels of VEGF, uPAR, uPA, and PAI-1. The VEGF level was significantly associated with tumor size, vascular involvement. The levels of uPAR and PAI-1 were significantly associated with tumor size and depth of infiltration, and the uPAR level was associated with liver metastasis. The VEGF level was significantly correlated with the levels of uPAR and PAI-1. These results reveal that IL-8, VEGF, and PA system factors are contributed to tumor growth, invasion, and metastasis in CRC. Univariate analysis revealed that high levels of IL-8, VEGF, and uPAR were significantly associated with a shorter overall survival time; however, multivariate analysis identified only liver metastasis as an independent prognostic factor. In conclusion, IL-8 is responsible to tumor progression and liver metastasis of CRC, and the activation of PAS induced by IL-8 as well as VEGF may play an important role in the progression of CRC.

The transcriptional landscape of the mammalian genome

This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.