Platelets from metastatic cancer patients have increased aggregation and activation

Platelets from metastatic cancer patients have increased aggregation and activation

abstracts Annals of Oncology Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest. 1916P Platelets...

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abstracts

Annals of Oncology Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.

1916P

Platelets from metastatic cancer patients have increased aggregation and activation

M. Chauhan1, A. Thomas1, A. Goodall2, J. Wright3, D. Adlam3 Leicester Cancer Research Centre, University of Leicester, Leicester, UK, 2College of Life Sciences, University of Leicester, Leicester, UK, 3Cardiovascular Sciences, University of Leicester, Leicester, UK

genes during the embryonic stage, we suppose a Wnt pathway activated, poor prognostic subgroup in luminal B breast cancer which can be identified by the expression of HOX genes. The cluster prediction model by machine learning was acceptable for its future adaptation in clinical settings. We also proved that HOX genes strongly covariate within the gene family in cancer, not only during the embryonic stage. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.

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Long non-coding RNA E2F4as promotes tumor progression and predicts patient prognosis in human ovarian cancer

S-A. Park, L.K. Kim, H.J. Kim Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, Republic of Korea Background: The functions of many long non-coding RNAs (lncRNAs) in human cancers remain to be clarified. Induction of E2F4as (antisense) by Wnt signaling may contribute to carcinogenesis by reducing levels of the E2F4as cell cycle repressor in colorectal cancer. Disruption of Wnt signaling is common in ovarian cancer. Despite the proposed models of E2F4as function, the significance of E2F4as RNA remains unclear in cancer. In this study, we examined the expression level of E2F4as in the serum of ovarian cancer patients and the functional role of E2F4as in ovarian cancer. Methods: The serum samples were obtained from 116 pathological diagnosed ovarian cancer patients and 39 normal age-matched women. The expression of E2F4as was measured by real time RT-PCR. To investigate the role of E2F4as in cell proliferation, invasion, and migration, E2F4as expression in ovarian cancer cells was knocked down using RNA interference. Results: The expression of E2F4as was significantly higher in the serum of ovarian cancer patients than in control patients (P < 0.05). E2F4as siRNA in SKOV3 cells decreased cell proliferation, invasion, and migration. Moreover, Knockdown of E2F4as decreased the expression of epithelial-mesenchymal transition (EMT), which are important for cell motility and metastasis. Mechanistic investigation revealed that Notch1, Hes1 and p300 proteins could be inhibited by E2F4as depletion. Conclusions: These findings highlight the clinical significance of E2F4as in predicting the prognosis of ovarian cancer patients and suggest its potential in promoting tumor aggressiveness by regulation of the Notch signaling pathway and EMT-related mechanisms. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.

Pierre Fabre; Advisory / Consultancy, Speaker Bureau / Expert testimony: Amgen. A. Goodall: Research grant / Funding (institution): Hoffmann La Roche; Research grant / Funding (institution): AstraZeneca. D. Adlam: Research grant / Funding (institution): Abbott Vascular Inc; Research grant / Funding (institution): AstraZeneca. All other authors have declared no conflicts of interest.

1919P

FGF19 promotes esophageal squamous cell carcinoma progression by inhibiting autophagy

L. Ying1, M. Huang1, J. Jin2, Y. Wu1, D. Su2 Zhejiang Cancer Hospital, Zhejiang Cancer Research Institution, Hangzhou, China, 2 Department of Pathology, Zhejiang Cancer Hospital, Hangzhou, China

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Luminal B breast cancer prognosis prediction by comprehensive analysis of Homeobox genes

A. Nakashoji, T. Hayashida, S. Yamaguchi, Y. Kitagawa Department of Surgery, Keio University School of Medicine, Tokyo, Japan Background: Homeobox (HOX) family consists of 39 genes which act as master regulators in embryonic development. Each of the genes is also known to play key roles in progression of breast cancer, including epithelial to mesenchymal transition, tumor angiogenesis and endocrine therapy resistance. Although there are numerous reports on individual HOX genes and cancer, none of them have comprehensively analyzed the whole gene family. Since HOX genes strongly coordinate within the family during the embryonic period, we considered that the analysis of the whole HOX family is also indispensable in breast cancer. Methods: We collected 702 breast cancer data from four publicly available array datasets (GSE11121, GSE7390, GSE3494, GSE2990) and performed unsupervised hierarchal clustering into two clusters by the expression of HOX genes. We constructed model formulas for cluster prediction by dividing the samples into learning and validation groups. We used three machine learning methods: support-vector machine (SVM), neural network and Bayes. The model formulas were validated by validation samples. We also used 512 TCGA breast cancer data to calculate covariations of the genes in breast cancer. Results: By the clustering of four array datasets, the DFS of the two clusters in PAM50classified luminal B patients were statistically different (p ¼ 0.016), and the gene ontology analysis revealed that the Wnt pathway was activated in the poor prognostic cluster. All cluster prediction models for luminal B sample achieved accuracies of over 90%. From TCGA breast cancer data, we found that HOX genes covariate the most with other HOX genes, especially within the chromosomally proximal groups. Conclusions: Comprehensive analysis of the whole HOX family lead to the prediction of luminal B breast cancer prognosis. Considering that Wnt signaling controls HOX

Volume 30 | Supplement 5 | October 2019

Background: Esophageal squamous cell carcinoma (ESCC) with high mortality is particularly prevalent in China and the prognosis is poor. Although genetic amplification and overexpression of the fibroblast growth factor 19 (FGF19) gene are found in ESCC, mechanisms that contribute to such functional alterations remain elusive. Methods: Gene-Panel Sequencing was used to detect genetic variants that may be associated with a risk of ESCC. The effect of proliferation inhibition of LY2874455, which is inhibitor of fibroblast growth factor receptors (FGFR), was assessed in ESCC patientderived cell (PDC) and xenograft (PDX) models. Autophagic activity was evaluated by immunoblotting for microtubule-associated protein 1 light chain 3 (LC3) and p62. Results: Using Gene-Panel Sequencing of 161 FFPE tissues, we found that FGF19 copy number amplified in almost 30% ESCC. Pharmacological of FGF19/FGFR by LY2874455 significantly induces repression of FGF19 amplificated ESCC progression in either PDC or PDX models. Mechanistic study revealed that treatment with LY2874455 induced activity of autophagy by inhibiting the ERK/MAPK pathway not by AKT pathway. Conclusions: Our findings reveal that FGF19 amplification inhibits autophagic activity by increasing the phosphorylation level of ERK, which may play an essential role in the pathogenesis of ESCC. Using FGFR inhibitor may represent an effective strategy to suppress FGF19 amplificated ESCC development and progression. Legal entity responsible for the study: The authors. Funding: The Major Project of Health Commission of Zhejiang Province of China (No. WKJ-ZJ-1902), the Public Welfare Technology Foundation of Zhejiang Province of China (No. 2017C34001), Zhejiang high-level innovative talent program, and the 1022 program of Zhejiang Cancer Hospital. Disclosure: All authors have declared no conflicts of interest.

doi:10.1093/annonc/mdz268 | v775

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Background: Platelet activation by tumour cells contributes to critical steps in the formation of metastases. Mechanisms include protection of tumour cells from immune destruction, interaction of platelet receptors with tumour ligands to facilitate adhesion, and enrichment of the tumour microenvironment to promote extravasation and proliferation. This study investigated the differences in platelet activation markers in cancer patients compared to healthy donors, and the effect of the addition of in vitro antiplatelet agents. Methods: Blood was collected from consented healthy volunteers and patients with metastatic cancer. Platelet rich plasma was prepared. Light transmission aggregometry measured spontaneous aggregation of platelet samples, without the addition of exogenous agonists. Flow cytometry measured the platelet activation markers P-selectin and fibrinogen binding on unstimulated, untreated platelets, and on unstimulated platelets incubated with aspirin, Ticagrelor and dual antiplatelet therapy. Results: 62 cancer patients and 17 healthy donors provided blood samples. There was increased spontaneous aggregation of platelets from cancer patients compared to healthy platelets (961.1% vs 460.9% p ¼ 0.02). Platelets from cancer patients had increased basal levels of P-selectin expression compared to healthy platelets (17.262.7% vs 8.460.3%) and incubation of platelets with antiplatelets had no effect. There was no difference in the basal level of fibrinogen binding between populations, however incubation with dual antiplatelet therapy reduced baseline fibrinogen binding in platelets from cancer patients (3.160.7% vs 10.863.7%). Conclusions: Platelets from cancer patients are hyperactive and easily form aggregates compared to healthy platelets. Platelets from cancer patients have higher levels of the activation marker P-selectin. Aggregation requires fibrinogen binding and incubation with dual antiplatelet therapy reduces this binding in platelets from cancer patients. The interaction between tumour cells and platelets could be a potential biomarker of disease, and this is reduced by antiplatelet drugs. Further studies determining the effect of in vivo antiplatelet therapy on platelets in cancer patients are being undertaken. Clinical trial identification: EudraCT: 2014-004049-29; Start date: 10-03-2015. Legal entity responsible for the study: University of Leicester. Funding: AstraZeneca. Disclosure: A. Thomas: Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy: