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Proffered Paper: In young women with atypical hyperplasia, high ERβ expression in background breast lobules correlates with decreased risk of future breast cancer
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EACR24 Oral Presentations, Monday 11 July 2016 / European Journal of Cancer 61, Suppl. 1 (2016) S5–S8 Conclusion: We identify microenvironmental signaling (PgR signaling), oncogenic signaling (Her2) and cellular density as central regulators of early dissemination and metastasis. In light of the patient-derived data we suggest that (i) dissemination is mostly early and (ii) clones that evolved over time at the primary site and became pre-dominant are less able to disseminate. We predict the findings not only to be relevant for Her2-driven cancers but for many other cancers as well. No conflict of interest.
Monday 11 July 2016
10:45–12:30
Symposium
Tumour Suppressors 15 Proffered Paper: In young women with atypical hyperplasia, high ERb expression in background breast lobules correlates with decreased risk of future breast cancer T. Hieken1 , J. Carter2 , J. Hawse3 , T. Hoskin4 , M. Bois2 , M. Frost5 , L. Hartmann5 , D. Radisky6 , D. Visscher2 , A. Degnim1 . 1 Mayo Clinic, Surgery, Rochester- Minnesota, USA, 2 Mayo Clinic, Laboratory Medicine and Pathology, Rochester- Minnesota, USA, 3 Mayo Clinic, Biochemistry and Molecular Biology, Rochester- Minnesota, USA, 4 Mayo Clinic, Health Sciences Research, Rochester- Minnesota, USA, 5 Mayo Clinic, Oncology, Rochester- Minnesota, USA, 6 Mayo Clinic, Biochemistry and Molecular Biology, Jacksonville- Florida, USA Background: Estrogen receptor beta (ERb), a putative tumor suppressor, is highly expressed in normal breast epithelia. ERb is distinct from ERa and shows promise as a prognostic biomarker and target for anticancer therapy. Although ERb expression is lost in ~60% of breast cancers (BCs), its expression in the remaining 40% of cases is associated with enhanced therapeutic response and improved survival. However, its role as an inhibitor of carcinogenesis remains unknown. Atypical hyperplasia increases future BC risk 4-fold but further risk stratification is needed to improve patient care. Thus we investigated ERb expression as a potential biomarker in these high risk women. Methods: We examined ERb expression by immunohistochemistry in breast tissues from a cohort of 171 women with atypical hyperplasia diagnosed from 1967 to 1991. Nuclear ERb percent staining and intensity were scored in the atypia and background normal lobules. A calculated sum score (percent + intensity) was used to categorize ERb expression as low, moderate or high. Competing risks regression was used to assess associations of ERb expression with BC risk. Results: After 15 years median follow-up, 36 women developed BC. ERb expression was lower in the atypia lobules than in background lobules, by percent staining and intensity (both p < 0.001). Higher ERb expression in the atypia or background lobules decreased the risk of subsequent BC by 2 (p = 0.04) and 2.5-fold (p = 0.006) independent of other risk biomarkers. To explore the hypothesis that ERb may be more effective in an “estrogenrich” environment, we examined the association within age groups of premenopause (age <45), peri-menopause (age 45−55) and post-menopause (age >55). Interestingly, we observed a dramatic increase in BC risk in women < age 45 with low-moderate ERb expression compared to high ERb expression in background lobules (HR 15.2, 95% CI: 1.8 to >100), vs HR 1.5 (95% CI: 0.6−3.8) in women age 45−55 and HR 2.3 (95% CI: 0.8−7.4) for age >55. The 20-year cumulative BC incidence was 0% (0/15) for women < age 45 at biopsy with high ERb in background lobules vs 40% (6/15) for women < age 45 with low-moderate ERb expression (p = 0.0008). Conclusion: These data suggest ERb may be a useful BC risk biomarker and potential target for pharmacologic risk reduction. High background lobule ERb expression conferred the strongest protective effect in pre-menopausal women indicating that the tumor suppressive effects of ERb may be conferred through paracrine signaling, effects that are more robust in an estrogen-rich environment. Further investigation of the functions of ERb is warranted to understand the mechanisms by which it suppresses BC development in benign breast disease. No conflict of interest.
Monday 11 July 2016
14:00–15:45
Symposium
Novel Targeted Therapies 16 Proffered Paper: Targeting PA2G4, a novel MYCN co-factor, for the treatment of neuroblastoma J. Koach1 , J.E. Murray1 , J. McCarroll1 , G. Milazzo2 , G. Perini2 , M. Haber1 , M.D. Norris1 , J.I. Fletcher1 , B.B. Cheung1 , G.M. Marshall3 . 1 Children’s Cancer Institute of Australia for Medical Research, Lowy Cancer Research Centre, Sydney, Australia, 2 University of Bologna, Department of Pharmacy and Biotechnology, Bologna, Italy, 3 Kids Cancer Centre, Sydney Children’s Hospital, Sydney, Australia Introduction: MYCN oncogene amplification is found in one third of primary neuroblastoma at diagnosis, and correlates with poor prognosis. We have identified Proliferation-associated protein 2G4 (PA2G4) as a direct binding partner for MYCN oncoprotein. PA2G4 belongs to a family of DNA/RNA binding proteins already implicated in cell growth, apoptosis and differentiation. The long isoform of PA2G4 (p48) has a known oncogenic function, whereas the short isoform (p42) acts as a tumour suppressor. However, the role of PA2G4 in neuroblastoma and its link with MYCN is currently unknown. Material and Method: Using a panel of human neuroblastoma cell lines and 477 patient tumour samples, we analysed the expression of PA2G4 by real-time PCR and Western blotting. Co-immunoprecipitation and chromatin immunoprecipitation were performed to assess the interaction between MYCN and PA2G4. Protein half-life was measured by cycloheximide chase assays. PA2G4 and MYCN expression were suppressed using siRNAs specifically targeting these genes. PA2G4 overexpressing cells were xenograft into nude mice to assess tumorigenicity while the TH-MYCN mouse model was used to assess the effectiveness of a PA2G4 inhibitor, WS6. Nanoparticles were used to deliver siRNA targeting PA2G4 intratumorally into xenograft mice. Results and Discussion: For the first time, we have identified ProliferationAssociated protein 2G4 (PA2G4) as a direct protein-binding partner of MYCN which acts in a forward feedback expression loop with MYCN to drive neuroblastoma tumorigenesis. We found high expression of PA2G4 was a strong independent clinical predictor of poor survival and positively correlated with MYCN expression. Suppression of PA2G4 by siRNAs decreases neuroblastoma cell growth, cell migration and colony formation. Most significantly, our in vivo data showed stable overexpression of PA2G4 in a non-tumorigenic neuroblastoma cell line was able to induce tumour growth. Conversely, using nanoparticles to deliver siRNA targeting PA2G4, we were able to delay neuroblastoma tumour growth significantly in a mouse xenograft model. Furthermore, a small molecule known to bind PA2G4, WS6, significantly decreased PA2G4 levels in tumour tissue and tumorigenicity in TH-MYCN mice. Conclusion: Collectively, our data suggest that PA2G4 acts as an oncogenic co-factor, binding and protecting MYCN from proteolysis, thus increasing MYCN levels. Our research provides strong evidence demonstrating PA2G4 is a driver of tumorigenicity and for the first time identifies PA2G4 as a novel therapeutic target for the treatment of neuroblastoma. No conflict of interest.
Monday 11 July 2016
14:00–15:45
Symposium
Inflammation and Cancer 17 Proffered Paper: Obesity-induced inflammation and desmoplasia promote pancreatic cancer progression and resistance to chemotherapy J. Incio1 , P. Suboj2 , S. Chin1 , H. Liu1 , R. Soares3 , Y. Boucher1 , D. Fukumura1 , R. Jain1 . 1 Massachusetts General Hospital, Radiation Oncology, BostonMassachusetts, USA, 2 MGH, Radiation Oncology, Boston, USA, 3 Porto Medical School, Biochemistry, Porto, Portugal Background: With the current epidemic of obesity, the majority of pancreatic cancer patients are overweight or obese at diagnosis. Importantly, obesity worsens treatment outcomes in pancreatic cancer patients. Therefore, understanding the mechanisms that underlie the poorer prognosis of obese cancer patients is of paramount importance. Obesity causes inflammation and fibrosis in the normal pancreas due to the accumulation of dysfunctional hypertrophic adipocytes. Importantly, desmoplasia − a fibroinflammatory microenvironment − is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and we have shown that activation of pancreatic stellate cells (PSCs) via angiotensin-II type 1 receptor (AT1) pathway is a major contribution to tumor
EACR24 Oral Presentations, Monday 11 July 2016 / European Journal of Cancer 61, Suppl. 1 (2016) S5–S8 Conclusion: We identify microenvironmental signaling (PgR signaling), oncogenic signaling (Her2) and cellular density as central regulators of early dissemination and metastasis. In light of the patient-derived data we suggest that (i) dissemination is mostly early and (ii) clones that evolved over time at the primary site and became pre-dominant are less able to disseminate. We predict the findings not only to be relevant for Her2-driven cancers but for many other cancers as well. No conflict of interest.
Monday 11 July 2016
10:45–12:30
Symposium
Tumour Suppressors 15 Proffered Paper: In young women with atypical hyperplasia, high ERb expression in background breast lobules correlates with decreased risk of future breast cancer T. Hieken1 , J. Carter2 , J. Hawse3 , T. Hoskin4 , M. Bois2 , M. Frost5 , L. Hartmann5 , D. Radisky6 , D. Visscher2 , A. Degnim1 . 1 Mayo Clinic, Surgery, Rochester- Minnesota, USA, 2 Mayo Clinic, Laboratory Medicine and Pathology, Rochester- Minnesota, USA, 3 Mayo Clinic, Biochemistry and Molecular Biology, Rochester- Minnesota, USA, 4 Mayo Clinic, Health Sciences Research, Rochester- Minnesota, USA, 5 Mayo Clinic, Oncology, Rochester- Minnesota, USA, 6 Mayo Clinic, Biochemistry and Molecular Biology, Jacksonville- Florida, USA Background: Estrogen receptor beta (ERb), a putative tumor suppressor, is highly expressed in normal breast epithelia. ERb is distinct from ERa and shows promise as a prognostic biomarker and target for anticancer therapy. Although ERb expression is lost in ~60% of breast cancers (BCs), its expression in the remaining 40% of cases is associated with enhanced therapeutic response and improved survival. However, its role as an inhibitor of carcinogenesis remains unknown. Atypical hyperplasia increases future BC risk 4-fold but further risk stratification is needed to improve patient care. Thus we investigated ERb expression as a potential biomarker in these high risk women. Methods: We examined ERb expression by immunohistochemistry in breast tissues from a cohort of 171 women with atypical hyperplasia diagnosed from 1967 to 1991. Nuclear ERb percent staining and intensity were scored in the atypia and background normal lobules. A calculated sum score (percent + intensity) was used to categorize ERb expression as low, moderate or high. Competing risks regression was used to assess associations of ERb expression with BC risk. Results: After 15 years median follow-up, 36 women developed BC. ERb expression was lower in the atypia lobules than in background lobules, by percent staining and intensity (both p < 0.001). Higher ERb expression in the atypia or background lobules decreased the risk of subsequent BC by 2 (p = 0.04) and 2.5-fold (p = 0.006) independent of other risk biomarkers. To explore the hypothesis that ERb may be more effective in an “estrogenrich” environment, we examined the association within age groups of premenopause (age <45), peri-menopause (age 45−55) and post-menopause (age >55). Interestingly, we observed a dramatic increase in BC risk in women < age 45 with low-moderate ERb expression compared to high ERb expression in background lobules (HR 15.2, 95% CI: 1.8 to >100), vs HR 1.5 (95% CI: 0.6−3.8) in women age 45−55 and HR 2.3 (95% CI: 0.8−7.4) for age >55. The 20-year cumulative BC incidence was 0% (0/15) for women < age 45 at biopsy with high ERb in background lobules vs 40% (6/15) for women < age 45 with low-moderate ERb expression (p = 0.0008). Conclusion: These data suggest ERb may be a useful BC risk biomarker and potential target for pharmacologic risk reduction. High background lobule ERb expression conferred the strongest protective effect in pre-menopausal women indicating that the tumor suppressive effects of ERb may be conferred through paracrine signaling, effects that are more robust in an estrogen-rich environment. Further investigation of the functions of ERb is warranted to understand the mechanisms by which it suppresses BC development in benign breast disease. No conflict of interest.
Monday 11 July 2016
14:00–15:45
Symposium
Novel Targeted Therapies 16 Proffered Paper: Targeting PA2G4, a novel MYCN co-factor, for the treatment of neuroblastoma J. Koach1 , J.E. Murray1 , J. McCarroll1 , G. Milazzo2 , G. Perini2 , M. Haber1 , M.D. Norris1 , J.I. Fletcher1 , B.B. Cheung1 , G.M. Marshall3 . 1 Children’s Cancer Institute of Australia for Medical Research, Lowy Cancer Research Centre, Sydney, Australia, 2 University of Bologna, Department of Pharmacy and Biotechnology, Bologna, Italy, 3 Kids Cancer Centre, Sydney Children’s Hospital, Sydney, Australia Introduction: MYCN oncogene amplification is found in one third of primary neuroblastoma at diagnosis, and correlates with poor prognosis. We have identified Proliferation-associated protein 2G4 (PA2G4) as a direct binding partner for MYCN oncoprotein. PA2G4 belongs to a family of DNA/RNA binding proteins already implicated in cell growth, apoptosis and differentiation. The long isoform of PA2G4 (p48) has a known oncogenic function, whereas the short isoform (p42) acts as a tumour suppressor. However, the role of PA2G4 in neuroblastoma and its link with MYCN is currently unknown. Material and Method: Using a panel of human neuroblastoma cell lines and 477 patient tumour samples, we analysed the expression of PA2G4 by real-time PCR and Western blotting. Co-immunoprecipitation and chromatin immunoprecipitation were performed to assess the interaction between MYCN and PA2G4. Protein half-life was measured by cycloheximide chase assays. PA2G4 and MYCN expression were suppressed using siRNAs specifically targeting these genes. PA2G4 overexpressing cells were xenograft into nude mice to assess tumorigenicity while the TH-MYCN mouse model was used to assess the effectiveness of a PA2G4 inhibitor, WS6. Nanoparticles were used to deliver siRNA targeting PA2G4 intratumorally into xenograft mice. Results and Discussion: For the first time, we have identified ProliferationAssociated protein 2G4 (PA2G4) as a direct protein-binding partner of MYCN which acts in a forward feedback expression loop with MYCN to drive neuroblastoma tumorigenesis. We found high expression of PA2G4 was a strong independent clinical predictor of poor survival and positively correlated with MYCN expression. Suppression of PA2G4 by siRNAs decreases neuroblastoma cell growth, cell migration and colony formation. Most significantly, our in vivo data showed stable overexpression of PA2G4 in a non-tumorigenic neuroblastoma cell line was able to induce tumour growth. Conversely, using nanoparticles to deliver siRNA targeting PA2G4, we were able to delay neuroblastoma tumour growth significantly in a mouse xenograft model. Furthermore, a small molecule known to bind PA2G4, WS6, significantly decreased PA2G4 levels in tumour tissue and tumorigenicity in TH-MYCN mice. Conclusion: Collectively, our data suggest that PA2G4 acts as an oncogenic co-factor, binding and protecting MYCN from proteolysis, thus increasing MYCN levels. Our research provides strong evidence demonstrating PA2G4 is a driver of tumorigenicity and for the first time identifies PA2G4 as a novel therapeutic target for the treatment of neuroblastoma. No conflict of interest.
Monday 11 July 2016
14:00–15:45
Symposium
Inflammation and Cancer 17 Proffered Paper: Obesity-induced inflammation and desmoplasia promote pancreatic cancer progression and resistance to chemotherapy J. Incio1 , P. Suboj2 , S. Chin1 , H. Liu1 , R. Soares3 , Y. Boucher1 , D. Fukumura1 , R. Jain1 . 1 Massachusetts General Hospital, Radiation Oncology, BostonMassachusetts, USA, 2 MGH, Radiation Oncology, Boston, USA, 3 Porto Medical School, Biochemistry, Porto, Portugal Background: With the current epidemic of obesity, the majority of pancreatic cancer patients are overweight or obese at diagnosis. Importantly, obesity worsens treatment outcomes in pancreatic cancer patients. Therefore, understanding the mechanisms that underlie the poorer prognosis of obese cancer patients is of paramount importance. Obesity causes inflammation and fibrosis in the normal pancreas due to the accumulation of dysfunctional hypertrophic adipocytes. Importantly, desmoplasia − a fibroinflammatory microenvironment − is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and we have shown that activation of pancreatic stellate cells (PSCs) via angiotensin-II type 1 receptor (AT1) pathway is a major contribution to tumor