Targeting Tumor-Stromal IL6/STAT3 Signaling through IL1 Receptor Inhibition in Pancreatic Cancer

A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the presence of a dense, desmoplastic stroma and the consequent altered interactions between cancer cells and their surrounding tumor microenvironment (TME) that promote disease progression, metastasis, and chemoresistance. We have previously shown that IL6 secreted from pancreatic stellate cells (PSC) stimulates the activation of STAT3 signaling in tumor cells, an established mechanism of therapeutic resistance in PDAC. We have now identified the tumor cell-derived cytokine IL1α as an upstream mediator of IL6 release from PSCs that is involved in STAT3 activation within the TME. Herein, we show that IL1α is overexpressed in both murine and human PDAC tumors and engages with its cognate receptor IL1R1, which is strongly expressed on stromal cells. Further, we show that IL1R1 inhibition using anakinra (recombinant IL1 receptor antagonist) significantly reduces stromal-derived IL6, thereby suppressing IL6-dependent STAT3 activation in human PDAC cell lines. Anakinra treatment results in significant reduction in IL6 and activated STAT3 levels in pancreatic tumors from Ptf1a^Cre/+;LSL-Kras^G12D/+; Tgfbr2^flox/flox (PKT) mice. Additionally, the combination of anakinra with cytotoxic chemotherapy significantly extends overall survival compared with vehicle treatment or anakinra monotherapy in this aggressive genetic mouse model of PDAC. These data highlight the importance of IL1 in mediating tumor-stromal IL6/STAT3 cross-talk in the TME and provide a preclinical rationale for targeting IL1 signaling as a therapeutic strategy in PDAC.

Combined Blockade of MEK and CDK4/6 Pathways Induces Senescence to Improve Survival in Pancreatic Ductal Adenocarcinoma

Activating KRAS mutations, a defining feature of pancreatic ductal adenocarcinoma (PDAC), promote tumor growth in part through the activation of cyclin-dependent kinases (CDK) that induce cell-cycle progression. p16INK4a (p16), encoded by the gene CDKN2A, is a potent inhibitor of CDK4/6 and serves as a critical checkpoint of cell proliferation. Mutations in and subsequent loss of the p16 gene occur in PDAC at a rate higher than that reported in any other tumor type and results in Rb inactivation and unrestricted cellular growth. Therefore, strategies targeting downstream RAS pathway effectors combined with CDK4/6 inhibition (CDK4/6i) may have the potential to improve outcomes in this disease. Herein, we show that expression of p16 is markedly reduced in PDAC tumors compared with normal pancreatic or pre-neoplastic tissues. Combined MEK inhibition (MEKi) and CDK4/6i results in sustained downregulation of both ERK and Rb phosphorylation and a significant reduction in cell proliferation compared with monotherapy in human PDAC cells. MEKi with CDK4/6i reduces tumor cell proliferation by promoting senescence-mediated growth arrest, independent of apoptosis in vitro We show that combined MEKi and CDK4/6i treatment attenuates tumor growth in xenograft models of PDAC and improves overall survival over 200% compared with treatment with vehicle or individual agents alone in Ptf1acre/+ ;LSL-KRASG12D/+ ;Tgfbr2flox/flox (PKT) mice. Histologic analysis of PKT tumor lysates reveal a significant decrease in markers of cell proliferation and an increase in senescence-associated markers without any significant change in apoptosis. These results demonstrate that combined targeting of both MEK and CDK4/6 represents a novel therapeutic strategy to synergistically reduce tumor growth through induction of cellular senescence in PDAC.

Assessment of thirty-day readmission rate, timing, causes and predictors after hospitalization with COVID-19

BACKGROUND

There are limited data on the characteristics of 30-day readmission after hospitalization with coronavirus disease 2019 (COVID-19).

OBJECTIVES

To examine the rate, timing, causes, predictors and outcomes of 30-day readmission after COVID-19 hospitalization.

METHODS

From 13 March to 9 April 2020, all patients hospitalized with COVID-19 and discharged alive were included in this retrospective observational study. Multivariable logistic regression was used to identify the predictors of 30-day readmission, and a restricted cubic spline function was utilized to assess the linearity of the association between continuous predictors and 30-day readmission.

RESULTS

A total of 1062 patients were included in the analysis, with a median follow-up time of 62 days. The mean age of patients was 56.5 years, and 40.5% were women. At the end of the study, a total of 48 (4.5%) patients were readmitted within 30 days of discharge, and a median time to readmission was 5 days. The most common primary diagnosis of 30-day readmission was a hypoxic respiratory failure (68.8%) followed by thromboembolism (12.5%) and sepsis (6.3%). The patients with a peak serum creatinine level of ≥1.29 mg/dL during the index hospitalization, compared to those with a creatinine of <1.29 mg/dL, had 2.4 times increased risk of 30-day readmission (adjusted odds ratio: 2.41; 95% CI: 1.23-4.74). The mortality rate during the readmission was 22.9%.

CONCLUSION

With 4.5% of the thirty-day readmission rate, COVID-19 survivors were readmitted early after hospital discharge, mainly due to morbidities of COVID-19. One in five readmitted COVID-19 survivors died during their readmission.

Effects of calcium-magnesium carbonate and calcium-magnesium hydroxide as supplemental sources of magnesium on microbial fermentation in a dual-flow continuous culture

Supplemental sources of Mg can also aid in ruminal pH regulation due to their alkaline properties. Magnesium oxide (MgO) is the most common source of Mg for ruminants and can help controlling ruminal pH; however, the alkaline potential of other sources of Mg has not been evaluated. We aimed to evaluate the inclusion of calcium–magnesium carbonate (CaMg(CO₃)₂) and calcium–magnesium hydroxide (CaMg(OH)₄) alone or in combination as supplemental sources of Mg in corn silage-based diets and its impact on ruminal microbial fermentation. We hypothesized that inclusion of CaMg(OH)₄ would allow for ruminal fermentation conditions resulting in a greater pH compared to the inclusion of CaMg(CO₃)₂. Four treatments were defined by the supplemental source of Mg in the diet: 1) Control (100% MgO, plus sodium sesquicarbonate as a buffer); 2) CO₃ [100% CaMg(CO₃)₂]; 3) OH [100% CaMg(OH)₄]; and 4) CO₃/OH [50% Mg from CaMg(CO₃)₂, 50% Mg from CaMg(OH)₄]. Nutrient concentration was held constant across treatments (16% CP, 30% NDF, 1.66 Mcal NEl/kg, 0.67% Ca, and 0.21% Mg). Four fermenters were used in a 4 × 4 Latin square design with four periods of 10 d each. Samples were collected for analyses of nutrient digestibility, soluble Mg, VFA, and NH₃, while pH was measured at 0, 1, 2, 4, 6, 8, and 10 h post morning feeding to estimate % time when pH was below 6 (pH-B6) and area under the pH curve for pH below 6.0 (pH-AUC). Bacteria pellets were harvested for ¹⁵N analysis and estimates of N metabolism. Treatment effects were analyzed with the mixed procedure of SAS, while effects of using either CaMg(CO₃)₂ or CaMg(OH)₄ as Mg source in comparison to Control treatment were evaluated by orthogonal contrasts. Similar pH-related variables were observed for Control, OH, and CO₃/OH treatments, which had smaller pH-AUC and pH-B6 than CO₃ (P ≤ 0.01). Butyrate molar proportion was greater in Control and CO₃/OH than in CO₃ and OH (P = 0.04). Orthogonal contrasts showed lower flow of bacterial N (P = 0.04), lower butyrate molar proportion (P = 0.08) and greater pH-AUC (P = 0.05) for diets with CaMg(CO₃)₂ in comparison with the Control. Concentration of soluble Mg in ruminal fluid (P = 0.73) and nutrient digestibility (P ≥ 0.52) were similar across treatments. Under the conditions of this experiment, using CaMg(OH)₄ alone or combined with CaMg(CO₃)₂ allowed for a less acidic ruminal fermentation pattern than a diet with only CaMg(CO₃)₂.

[Effect of 2-year resistance exercises on cardiovascular disease risk in prediabetes patients]

Objective: To investigate the effect of a 2-year resistance and aerobic training on reducing the risk of cardiovascular disease in patients with prediabetes. Methods: A total of 248 patients with prediabetes were enrolled from Chinese and Western Medicine Hospital Affiliated to Nanjing University of Chinese Medicine from January to April 2014, and Danyang People's Hospital and The First Affiliated Hospital of Guangxi Medical University from May to December 2014.Based on random number table method, the patients were divided into 3 groups: the resistance training group (RT group, 82 cases), the aerobic training group (AT group, 83 cases) and control group (83 cases). Participants in the RT group and the AT group underwent a total of 24 months of exercise training. Changes in indicators (blood glucose,blood lipid, etc.) at baseline and the end of 12 and 24 months among the groups were compared. Results: After intervention, glycosylated hemoglobin (HbA1c), low density lipoprotein cholesterol (LDL-C), blood pressure and homeostasis model 2 insulin resistance index (HOMA2-IR) in the RT and AT groups tended to decrease, and the steady state model 2 β cell function index (HOMA2-β) tended to increase. At the end of 24 months, HbA1c [5.80 (5.43, 6.20) %, 5.70 (5.50, 6.00)% vs. 6.20 (5.70, 6.60) %, all P ≤ 0.01], LDL-C [3.07 (2.69, 3.58) mmol/L, 2.97 (2.62, 3.95) mmol/L vs. 3.21(2.54, 3.78) mmol/L, all P<0.05] and HOMA2-IR [0.96 (0.82, 1.47), 1.20 (0.99, 1.43) vs. 1.34 (1.09, 1.51), all P<0.05] were significantly decreased in the RT and AT groups than in the control group. In addition, HOMA2-β [84.50 (60.55, 107.33), 93.00 (78.60, 119.75) vs. 53.40 (37.70, 80.40), all P = 0.001] was significantly increased in the AT and RT groups compared with that in the control group. There were no significant differences in triglyceride (TG) and high-density lipoproteincholesterol (HDL-C) levels between the training groups and the control group (all P>0.05). After adjusting for age, sex and blood pressure, the cardiovascular risk of prediabetes was significantly reduced in RT (P =0.017) and AT groups (P =0.018). The Cox regression analyses showed that both the resistance training (HR=0.419, 95%CI =0.415-0.942, P=0.037) and the aerobic training (HR=0.310, 95%CI=0.447-0.866, P=0.026) were protective factors for cardiovascular disease in prediabetic patients after adjustment of age, sex, statins, body mass index and waist-to-hip ratio, which reduced the risks of cardiovascular disease in prediabetic patients by 58.1% and 69.0%, respectively. Conclusions: Two years of aerobic and resistance training interventions have obvious advantages on glycemic and insulin resistance control in prediabetes patients. The resistance training can reduce the risk of cardiovascular disease, and it is, thus, recommended for prediabetic patients without obvious exercise contraindications.

Abstract PO-049: Single-cell transcriptomic analysis reveals interleukin-1 inhibition suppresses inflammatory cancer-associated fibroblast signaling and improves the immune response in pancreatic cancer

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is resistant to immune checkpoint blockade due to its intrinsic immunosuppressive properties. The fibroinflammatory stroma, particularly inflammatory cancer associated fibroblasts (CAFs), are a key determinant of the immune microenvironment in PDAC, however therapies aimed at broad-based targeting of PDAC stroma have been decidedly unsuccessful. Recently, interleukin-1α (IL-1) has emerged as a critical mediator of CAF activation and orchestrator of immune suppression in PDAC. We sought to explore the effects of IL-1 blockade on reprogramming the immune microenvironment and enhancing susceptibility to checkpoint inhibition through suppression of inflammatory stromal signaling in PDAC. Methods: Ptf1acre/+;LSL-KrasG12D/+; Tgfbr2flox/flox (PKT) mice were treated with the recombinant IL-1 receptor antagonist (anakinra, 50 mg/kg IP BID) or vehicle control. Single-cell cDNA library generation was performed using the 10× Chromium System. Expression matrices were processed using the R package Seurat 3.0 and clustered using AUC-based scoring algorithm. Immunophenotyping experiments were performed on single-cell suspensions using the Cytoflex platform. For survival studies, PKT mice were treated with vehicle, anti-PD1 antibody (200 μg/twice weekly), anakinra, or combination until moribund. Tissues were further processed for downstream qPCR and histologic analyses. Human pancreatic stellate cell (hPSC) and immortalized CAF cell lines procured from patient-derived xenografts were utilized for in vitro mechanistic studies. Results: Single-cell analysis revealed that anakinra treatment in PKT mice reduced levels of numerous pro-inflammatory CAF cytokines, including Cxcl1 and Il6, within CAF subclusters. Confirmatory qPCR of bulk tumor samples revealed a significant reduction in Cxcl1 and Il6 gene transcription and a global reduction in stromal fibrosis with anakinra treatment. IL-1 inhibition selectively reduced alternatively-activated macrophage (CD11b+F480+CD206+) and PMN-MDSC (CD11b+Ly6G+) populations within PDAC tumors. Combination treatment of anakinra with anti-PD1 antibody reduced tumor weight, increased intratumoral levels of effector memory (CD8+CD44+CD62L-) and activated cytotoxic (CD8+CD107+) T cells, and improved overall survival in PKT mice. In vitro studies demonstrated that conditioned media from PDAC tumor cells significantly activated Cxcl1 and Il6 gene transcription in hPSCs and CAFs in an IL-1α-dependent manner. IL-1-mediated transcription of these cytokines was abrogated by selective inhibition of both the p38 MAPK and NFκB cascades, demonstrating a coordinated effort between these signaling pathways in modulating the IL-1-induced stress response in stromal cells. Conclusions: These findings provide important mechanistic data and compelling pre-clinical evidence to explore IL-1 inhibition in combination with immune checkpoint blockade in PDAC patients.

Citation Format: Austin R. Dosch, Samara Singh, Xizi Dai, Siddharth Mehra, Anna Bianchi, Iago De Castro Silva, Supriya Srinivasan, Nagaraj Nagathihalli, Jashodeep Datta, Nipun B. Merchant. Single-cell transcriptomic analysis reveals interleukin-1 inhibition suppresses inflammatory cancer-associated fibroblast signaling and improves the immune response in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-049.

Abstract PO-056: Targeting of cancer associated fibroblast-specific MEK1 and STAT3 to overcome immunosuppressive microenvironment in Pancreatic Ductal Adenocarcinoma (PDAC)

Background Activating KRAS mutations, stromal desmoplasia, and immune exclusion are fundamental to therapeutic resistance in PDAC. We have previously shown an inverse correlation of reciprocally-activated MEK1 and STAT3 signaling, combined inhibition of which remodels the tumor stroma resulting in enhanced effector immune cell infiltration and improved survival in an aggressive genetically engineered mouse model (GEM) of PDAC. Based on these results, we sought to determine the effects of cancer-associated fibroblasts (CAF) specific silencing of MEK1 and STAT3 on the immune microenvironment and PDAC tumor growth. Methods CRISPR/Cas9 ablation of MEK1 and STAT3 was performed in CAFs derived from LSL-KrasG12D/+; Trp53fl/+; Pdx1-Cre (KPC) GEM. RNA sequencing identified transcriptomics changes in MEK1 KO / STAT3KO CAFs vs. wildtype KPC-CAFs. The effect of CAF-specific deletion of MEK1/STAT3 in modulating the immune microenvironment was assessed using multiplex immunophenotyping in orthotopic tumor implantation models of co-cultured KPC tumor cells with MEK1KO / STAT3KO CAFs. Results CAF-specific MEK1/STAT3 ablation resulted in significant retardation of growth kinetics of 3D spheroids, as well as migration and invasion, in KPC tumor cell: CAF co-culture systems. Interestingly, the transcriptome of MEK1KO/ STAT3KO CAFs was strongly enriched for antigen-presenting machinery, IL-12, and IFN signaling pathways, while revealing downregulation of Wnt/β-catenin and collagen pathways. Multiplex cytokine arrays confirmed dramatically increased IL-12p70, IL-2, CXCL10 secretion, and decreased IL-10 secretion in MEK1KO / STAT3KO vs. wildtype. Flow cytometric analysis confirmed increased expression of class I and class II MHC, but not co stimulatory molecules, expression in these double knock out CAFs. Orthotopic implantation of MEK1KO / STAT3KO vs. wildtype CAFs with KPC tumor cells in C57BL/6 pancreata revealed significantly increased infiltration of activated effector degranulating CD8+ T-cells (CD62LlowCD44highCD107low) with reduced exhaustion phenotype (PD1highCD107low)in MEK1KO /STAT3KO vs. wild type CAF tumor-bearing mice. Conclusion CAF-specific ablation of MEK1 and STAT3 generates features suggestive of augmented antigen-presenting capacity and results in adaptive immune invigoration in the PDAC tumor microenvironment. Further mechanistic studies exploring this novel CAF-specific phenotype is warranted.

Citation Format: Siddharth Mehra, Xizi Dai, Anna Bianchi, Austin Dosch, Iago de Castro Silva, Prateek Sharma, Samara Singh, Supriya Srinivasan, Nagaraj Nagathihalli, Jashodeep Datta, Nipun Merchant. Targeting of cancer associated fibroblast-specific MEK1 and STAT3 to overcome immunosuppressive microenvironment in Pancreatic Ductal Adenocarcinoma (PDAC) [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-056.

Discontinuous Transitions and Rhythmic States in the D-Dimensional Kuramoto Model Induced by a Positive Feedback with the Global Order Parameter

From fireflies to cardiac cells, synchronization governs important aspects of nature, and the Kuramoto model is the staple for research in this area. We show that generalizing the model to oscillators of dimensions higher than 2 and introducing a positive feedback mechanism between the coupling and the global order parameter leads to a rich and novel scenario: the synchronization transition is explosive at all even dimensions, whilst it is mediated by a time-dependent, rhythmic, state at all odd dimensions. Such a latter circumstance, in particular, differs from all other time-dependent states observed so far in the model. We provide the analytic description of this novel state, which is fully corroborated by numerical calculations. Our results can, therefore, help untangle secrets of observed time-dependent swarming and flocking dynamics that unfold in three dimensions, and where this novel state could thus provide a fresh perspective for as yet not understood formations.

THU0048 THE FUNCTION CHANGES OF SNPS IN THE P2X7 RECEPTOR BY ALA348TO THR, GLU496TO ALA AND ARG307TO GLN IN THP-1 CELLS WITH HIGH URIC ACID

Background:

Previous studies[1] have shown that ATP acts on the sputum receptor P2X ligand-gated ion channel 7 (P2X7R) as a second signal to induce gouty arthritis.

Objectives:

In this study, the functional changes of three SNP genotypes, Ala348 to Thr, Glu 496 to Ala and Arg307 to Gln, in P2X7R were analyzed with high uric acid.

Methods:

After transfection of HEK-293T cells by lentivirus, observing the uptake ability of HEK-293T cells to ethidium bromide. The effect of three different mutants on the P2X7 receptor was thus observed on the P2X7 channel. In addition, THP-1 cells were also transfected, stable expression of a THP-1 cell line that has been transfected with a wild-type or different mutants and thus established. Then three types were set up separately, and each type was randomized into three groups: MSU(labeled M), MSU+ATP (labeled MA), and unstimulated control group (labeled C).Detection of IL-1β protein expression level in serum by ELISA and NLRP3, ASC and Caspase-1 mRNA levels in transfected THP-1 cells by qRT-PCR.

Results:

1.These three variants have different effects on the uptake function of ATP-induced ethidium+bromide in transfection of HEK-293T cells by lentivirus. Ala348to Thr increased P2X7-dependent ethidium+bromide uptake (145% of wild-type P2X7response, P<0.001). In contrast, Absent or very reduced P2X7function was found in Glu496to Ala and Arg307to Gln subjects, appeared to abolish P2X7-dependent dye uptake (38% and 32% of wild-type P2X7responses, P<0.001,), who were compared with wild-type.

2.Compared the IL-1β levels of the three variants with the wide-type and empty virus in THP-1 cells, the Ala348to Thr mutation significantly up-regulated the serum levels of IL-1β compared with the wide-type and empty virus in group MA with high uric acid (P=0.0007;P=0.013, respectively). Moreover, similar results have also been shown in IL-1β mRNA expressions (P=0.0334; P=0.0307, respectively). The Glu496to Ala and Arg307to Gln mutations down-regulated the serum levels of IL-1β compared with the wide-type in group MA (P=0.0189;P=0.0164, respectively).

3.NLRP3 mRNA was significantly increased in the Ala348to Thr mutation compared with the wide-type and empty virus in group MA (p =0.0003;P=0.0001, respectively). However, NLRP3 mRNA was significantly reduced in the Glu496to Ala and Arg307to Gln mutations compared with the wide-type in group MA (p =0.0294;P=0.0279, respectively).

4.Wild-type was signifcantly higher than empty virus in the ASC gene expression in group MA(P=0.0022). Morever, the Ala348to Thr mutation was higher than empty virus while Arg307to Gln mutation was lower than that in group MA (P=0.0138;P=0.0283, respectively).

5.Unlike NLRP3 gene expression, the data showed that the expression of caspase-1 mRNA in group C, M and MA all with no statistical significance, respectively (P>0.05).

Conclusion:

Our data revealed that Ala348to Thr up-regulate the functional status of P2X7R and Glu496to Ala and Gln460to Arg down-regulate the functional status of P2X7R, which resulted in a significant increase or decrease in IL-1β and NLRP3 expression levels with high uric acid.

References:

[1]Tao JH, Zhang Y, Li XP, et al. P2X7R: a potential key regulator of acute gouty arthritis[J].Semin Arthritis Rheum, 2013,43(3):376–380.

Disclosure of Interests:

None declared

AB0530 CHARACTERISTICS AND MEDIUM-TERM OUTCOMES OF TAKAYASU ARTERITIS–RELATED RENAL ARTERY STENOSIS: ANALYSIS OF A LARGE CHINESE COHORT

Background:

The incidence of renal artery stenosis in Takayasu arteritis (TA) was 20%–60% according to previous reports. The specific characteristics of patients with TA-related renal artery stenosis and the effect of revascularization procedures on prognosis have not been fully investigated.

Objectives:

To investigate the characteristics of patients with TA-related renal artery stenosis and identify the predictors of medium-term adverse outcomes.

Methods:

Data for 567 patients registered in a large prospective observational cohort-the East China Takayasu arteritis cohort-up to April 30, 2019, were retrospectively analyzed.

Results:

Renal artery stenosis was confirmed in 172/567 (30.34%) patients, with left renal artery involvement seen in 73/172 (42.44%) patients. Renal insufficiency at presentation (HR = 2.37, 95% CI: 1.76-15.83, p = 0.03), bilateral renal artery involvement (HR = 6.95, 95% CI: 1.18-21.55, p = 0.01), and severe (>75%) stenosis (HR = 4.75, 95% CI 1.08-11.33, p = 0.05) were predictors of adverse outcomes. Revascularization was performed for 46/172 (26.74%) patients. Patients without preoperative treatment had higher rate of restenosis (44.44% vs. 15.79%, p < 0.01) and hypertension deterioration (25.93% vs. 10.53%, p < 0.01) after the procedure. Non-receipt of preoperative treatment (HR = 6.5, 95% CI: 1.77-32.98, p = 0.04) and active disease at revascularization (HR = 4.21, 95% CI 2.01-21.44, p = 0.04) were independent predictors of adverse outcomes after revascularization.

Conclusion:

Patients with uncontrolled or worsening hypertension or/and renal function may benefit from revascularization. Those who have received preoperative treatment may have more favorable revascularization outcomes. Prognosis appears to be poorer for patients with renal insufficiency at presentation, bilateral artery involvement, and severe stenosis.

References:

[1]Watanabe Y, Miyata T, Tanemoto K. Current clinical features of new patients with Takayasu arteritis observed from a cross-country research in Japan: age and sex specificity. Circulation 2015; 132: 1701-9.

[2]Peng M, Jiang XJ, Dong H, et al. Etiology of renal artery stenosis in 2047 patients: a single-center retrospective analysis during a 15-year period in China. J Hum Hypertens 2016; 30: 124-8

Disclosure of Interests:

None declared

Comparative transcriptome profiling reveals candidate genes related to insecticide resistance of Glyphodes pyloalis

Glyphodes pyloalis Walker (Lepidoptera: Pyralididae) is a common pest in sericulture and has developed resistance to different insecticides. However, the mechanisms involved in insecticide resistance of G. pyloalis are poorly understood. Here, we present the first whole-transcriptome analysis of differential expression genes in insecticide-resistant and susceptible G. pyloalis. Clustering and enrichment analysis of DEGs revealed several biological pathways and enriched Gene Ontology terms were related to detoxification or insecticide resistance. Genes involved in insecticide metabolic processes, including cytochrome P450, glutathione S-transferases and carboxylesterase, were identified in the larval midgut of G. pyloalis. Among them, CYP324A19, CYP304F17, CYP6AW1, CYP6AB10, GSTs5, and AChE-like were significantly increased after propoxur treatment, while CYP324A19, CCE001c, and AChE-like were significantly induced by phoxim, suggesting that these genes were involved in insecticide metabolism. Furthermore, the sequence variation analysis identified 21 single nucleotide polymorphisms within CYP9A20, CYP6AB47, and CYP6AW1. Our findings reveal many candidate genes related to insecticide resistance of G. pyloalis. These results provide novel insights into insecticide resistance and facilitate the development of insecticides with greater specificity to G. pyloalis.

Combined Src/EGFR Inhibition Targets STAT3 Signaling and Induces Stromal Remodeling to Improve Survival in Pancreatic Cancer

Lack of durable response to cytotoxic chemotherapy is a major contributor to the dismal outcomes seen in pancreatic ductal adenocarcinoma (PDAC). Extensive tumor desmoplasia and poor vascular supply are two predominant characteristics which hinder the delivery of chemotherapeutic drugs into PDAC tumors and mediate resistance to therapy. Previously, we have shown that STAT3 is a key biomarker of therapeutic resistance to gemcitabine treatment in PDAC, which can be overcome by combined inhibition of the Src and EGFR pathways. Although it is well-established that concurrent EGFR and Src inhibition exert these antineoplastic properties through direct inhibition of mitogenic pathways in tumor cells, the influence of this combined therapy on stromal constituents in PDAC tumors remains unknown. In this study, we demonstrate in both orthotopic tumor xenograft and Ptf1a^cre/+;LSL-Kras^G12D/+;Tgfbr2^flox/flox (PKT) mouse models that concurrent EGFR and Src inhibition abrogates STAT3 activation, increases microvessel density, and prevents tissue fibrosis in vivo. Furthermore, the stromal changes induced by parallel EGFR and Src pathway inhibition resulted in improved overall survival in PKT mice when combined with gemcitabine. As a phase I clinical trial utilizing concurrent EGFR and Src inhibition with gemcitabine has recently concluded, these data provide timely translational insight into the novel mechanism of action of this regimen and expand our understanding into the phenomenon of stromal-mediated therapeutic resistance. IMPLICATIONS: These findings demonstrate that Src/EGFR inhibition targets STAT3, remodels the tumor stroma, and results in enhanced delivery of gemcitabine to improve overall survival in a mouse model of PDAC.

Abstract A11: Combined Src and EGFR inhibition targets STAT3 to induce stromal remodeling and increase drug delivery to improve survival in a mouse model of pancreatic cancer

Lack of durable response to cytotoxic chemotherapy is a major contributor to the dismal outcomes seen in pancreatic ductal adenocarcinoma (PDAC). Extensive tumor desmoplasia and poor vascular supply are two predominant characteristics that hinder the delivery of chemotherapeutic drugs into PDAC tumors and mediate resistance to therapy. Previously, we have shown that STAT3 is a key biomarker of therapeutic resistance to gemcitabine treatment in PDAC, which can be overcome by combined inhibition of the Src kinase and epidermal growth factor receptor (EGFR) pathways. Although it is well established that concurrent EGFR and Src inhibition exert these anti-eoplastic properties through inhibiting mitogenic pathways in tumor cells directly, the influence of this combined therapy on stromal constituents in PDAC tumors remains unknown. In the present study, we demonstrate in both orthotopic tumor xenografts and Ptf1acre/+;LSL-KrasG12D/+;Tgfbr2flox/flox (PKT) mouse models that concurrent EGFR and Src inhibition abrogates STAT3 activation, resulting in stromal remodeling through the depletion of tumor collagen content, increasing microvessel density, and preventing tissue fibrosis in vivo. Furthermore, these stromal changes resulting from combined pathway inhibition produce a direct increase in intratumoral gemcitabine levels as determined by MALDI-IMS and improve overall survival in PKT mice treated with combined EGFR and Src inhibition with gemcitabine. As a phase 1 clinical trial utilizing concurrent EGFR and Src inhibition in combination with gemcitabine has recently concluded, these data provide translational insight into the novel mechanism of action of this regimen and expand our understanding into the phenomenon of stromal-mediated therapeutic resistance.

Citation Format: Austin R. Dosch, Xizi Dai, Michelle L. Reyzer, Deukwoo Kwon, Richard Caprioli, Nipun B. Merchant, Nagaraj S. Nagathihalli. Combined Src and EGFR inhibition targets STAT3 to induce stromal remodeling and increase drug delivery to improve survival in a mouse model of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A11.

Gene duplication and subsequent functional diversification of sucrose hydrolase in Papilio xuthus

Sucrose is the main product of photosynthesis in plants, providing a rich carbon and energy source for the physiological growth and development of insects. In a previous study, we identified a novel sucrose hydrolase (SUH) in the larval midgut of moths. Intriguingly, there are two copies of Suh, namely Suh1 and Suh2, in several species of butterflies. However, the biochemical characteristics of SUHs in butterflies remain unclear. In this study, we found that this duplication and subsequent diversification produced two Suh genes in Papilio xuthus. These two PxSuh genes were significantly divergent in terms of their expression pattern and enzyme properties. PxSuh messenger RNA expression was highest during the larval stage, reduced in the prepupal and pupal stages and, for PxSuh1, slightly increased again in the adult. The observed levels of PxSuh2 were overall below those of PxSuh1 amongst the development stages examined. Compared with PxSUH2, which has maintained the original gene function of maltose hydrolysis, PxSUH1 exhibits substrate specificity for sucrose with an optimum enzyme activity occurring at an alkaline pH. The data show that PxSuh1 is evolutionarily adapted for effective functioning in an alkaline digestive system. Furthermore, we find that functional diversification of Suh facilitates P. xuthus to digestive carbohydrate of host plants. Thus, our findings offer new insights into the ecological and evolutionary adaptation of digestive enzymes in butterflies.

Downregulation of miR-1294 associates with prognosis and tumor progression in epithelial ovarian cancer

OBJECTIVE

Increasing evidence has revealed that microRNAs (miRNAs) act as key players in the regulation of tumor growth and metastasis in epithelial ovarian cancer (EOC). However, the clinical role and functional effects of miR-1294 in EOC remain unknown.

PATIENTS AND METHODS

We examined the expression of miR-1294 in 69 cases of EOC tissues and cell lines by quantitative Real-time polymerase chain reaction (qRT-PCR). The associations of miR-1294 expression with clinicopathologic features and overall survival of EOC patients were analyzed. Biological functional effects of miR-1294 expression on cell growth were analyzed using Cell Counting Kit-8 (CCK8) assays and flow cytometry assays in vitro.

RESULTS

In the present study, we identified that miR-1294 expression was lower in 76 specimens of EOC compared to adjacent normal tissues. Lower miR-1294 expression was related to FIGO stage, lymph node metastasis and shorter overall survival rate in EOC patients. Multivariate Cox analysis demonstrated that miR-1294 expression was an independent prognostic indicator of EOC patients. Gain function assays showed that miR-1294 overexpression inhibited cell proliferation and cell cycle progression in EOC.

CONCLUSIONS

Our results indicated that miR-1294 acted as a prognostic biomarker and potential target of EOC treatment.

MiR-29c suppresses cell invasion and migration by directly targeting CDK6 in gastric carcinoma

OBJECTIVE

Gastric carcinoma (GC) is one common malignant tumor with high morbidity and mortality rates all over the world. Recently, numerous studies have showed that the microRNAs (miRNAs) dysregulation was implicated in GC carcinogenesis. This research aimed to explore the potential associations between miR-29c and cyclin-dependent kinase 6 (CDK6) in GC.

PATIENTS AND METHODS

GC tissues and corresponding normal tissues were collected from 54 GC patients who underwent surgery at the Second Hospital of Anhui Medical University between 2015 and 2017. We measured the expressions of CDK6 and miR-29c in GC tissues using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). We next investigated the functions of miR-29c in GC cells by performing transwell assays. To further determine the correlation between miR-29c and CDK6 in GC cell invasion and migration, the rescue experiments were performed by co-transfecting miR-29c inhibitor and CDK6 siRNA into AGS cells.

RESULTS

MiR-29c expressions were significantly declined in GC tissues and cells. Additionally, functional assays showed that the miR-29c over-expression suppressed the invasion and migration capacities of GC cells. According to TargetScan and dual-luciferase reporter assays, CDK6 was identified as a new miR-29c target. Moreover, the knockout of CDK6 had similar effects as the miR-29c over-expression in GC cells. The current research indicated that miR-29c over-expression could inhibit tumor behaviors in GC partially via down-regulating CDK6.

CONCLUSIONS

We revealed that miR-29c down-regulated in GC tissues and cells. MiR-29c over-expression effectively suppressed the GC cell invasion and migration. Moreover, CDK6 was identified as a direct functional target of miR-29c in GC. The current study provides new insights for the GC treatment and suggests that miR-29c/CDK6 axis is a therapeutic candidate target for GC patients.

A new diagnostic index for sarcopenia and its association with short-term postoperative complications in patients undergoing surgery for colorectal cancer

AIM

Sarcopenia is a robust prognostic indicator of outcomes after surgery for colorectal cancer (CRC). However, there are no serum markers routinely available for estimating skeletal muscle mass (SMM). The present study aimed to describe a new sarcopenia index (SI), serum creatinine (Scr) × cystatin C-based glomerular filtration rate, and investigate its association with short-term complications after curative resection of CRC.

METHOD

Consecutive patients who underwent curative resection of CRC from December 2011 to January 2017 were retrospectively identified. Skeletal muscle cross-sectional area was analysed on L3 computed tomographic images. Receiver operating characteristic curve analysis showed that the cutoff points of SI for sarcopenia were below 56.1 in men and below 43.7 in women. Patients were classified into low and high SI groups in accordance with these cutoff values. The association between SI and body composition and the impact of preoperative SI on postoperative outcomes were analysed.

RESULTS

Among 417 patients, SI showed a stronger correlation with skeletal muscle area (SMA) (r = 0.537, P < 0.001) than with the Scr/cystatin C ratio (r = 0.469, P < 0.001) and Scr (r = 0.447, P < 0.001). The low SI group had a lower SMA, lower preoperative haemoglobin, a higher prevalence of sarcopenia and experienced more postoperative complications compared with the high SI group (all P < 0.001). Multivariate logistic regression analysis showed that the independent risk factors for overall complications were low preoperative haemoglobin, low SI, sarcopenia and American Society of Anesthesiologists grade ≥ 3.

CONCLUSION

This new SI is a simple and useful surrogate marker for estimating SMM, and is associated with outcomes after CRC surgery.

NGF increases FGF2 expression and promotes endothelial cell migration and tube formation through PI3K/Akt and ERK/MAPK pathways in human chondrocytes

OBJECTIVE

Vascular invasion is observed at the osteochondral junction in osteoarthritis (OA). Nerve growth factor (NGF) as an angiogenic factor is expressed in OA. This study is to investigate the effects of NGF on angiogenesis in vitro in human chondrocytes.

DESIGN

Articular cartilages of knee joints were harvested from healthy and OA patients. Expressions of NGF and tropomyosin-related kinase A (TrkA) were detected by western blot, Safranin-O and fast green staining and immunohistochemistry in cartilage. Expression of fibroblast growth factor 2 (FGF2) was detected by western blot in cultured chondrocytes. Chondrocytes were transfected by lentiviral vectors to knock down TrkA. Migration and tube formation of human microvascular endothelial cell (HMVEC) were assessed by using transwell co-culture with chondrocyte after treatment of NGF.

RESULTS

We confirmed expressions of NGF and TrkA were significantly up-regulated in OA. NGF induced expression of FGF2 in a time- and dose-dependent manner. Angiogenic activities of endothelial cells were greatly enhanced after co-cultured with NGF pre-treated chondrocytes, while knock-down of TrkA significantly abolished the above effects. We further found that NGF-induced expression of FGF2 promoted angiogenic activities of endothelial cells through PI3K/Akt and ERK/MAPK signaling pathways.

CONCLUSIONS

NGF promotes expression of FGF2 in vitro via PI3K/Akt and ERK/MAPK signaling pathways in human chondrocytes and it increases angiogenesis, which is mediated by TrkA. NGF could be responsible for vascular up-growth from subchondral bone in OA.

Src kinase inhibition restores E-cadherin expression in dasatinib-sensitive pancreatic cancer cells

The Src family of non-receptor tyrosine kinases are frequently activated in pancreatic ductal adenocarcinoma (PDAC), contributing to disease progression through downregulation of E-cadherin and induction of epithelial-to-mesenchymal transition (EMT). The purpose of this study was to examine the efficacy of Src kinase inhibition in restoring E-cadherin levels in PDAC. Immunohistochemical analysis of human PDAC samples showed Src activation is inversely correlated with E-cadherin levels. Protein and mRNA levels of E-cadherin, the gene expression of its various transcriptional repressors (Zeb1, Snail, Slug, LEF-1, TWIST), and changes in sub-cellular localization of E-cadherin/β-catenin in PDAC cells were characterized in response to treatment with the Src inhibitor, dasatinib (DST). DST repressed Slug mRNA expression, promoted E-cadherin transcription, and increased total and membranous E-cadherin/β-catenin levels in drug-sensitive PDAC cells (BxPC3 and SW1990), however no change was observed in drug-resistant PANC1 cells. BxPC3, PANC1, and MiaPaCa-2 flank tumor xenografts were treated with DST to examine changes in E-cadherin levels in vivo. Although DST inhibited Src phosphorylation in all xenograft models, E-cadherin levels were only restored in BxPC3 xenograft tumors. These results suggest that Src kinase inhibition reverses EMT in drug-sensitive PDAC cells through Slug-mediated repression of E-cadherin and identifies E-cadherin as potential biomarker for determining response to DST treatment.