Abstract P4-08-30: Prognostication of immune related gene expression in patients with triple negative breast cancer

Introduction: To date, the role of immunotherapy with check point inhibitors and/or vaccines in the treatment of breast cancer (BC) is still debating, and the main focus of immunotherapy in BC is on triple negative subtype as a target population in many ongoing clinical trials. Translational research into identifying predictive and prognostic immune biomarkers is of particular clinical relevance, but, there are currently no definite prognostic and predictive immune biomarkers in BC, especially in triple negative breast cancer(TNBC). We investigated the expression profiles of immune genes in patients with TNBC to identify the prognostic value of immune genes in search of clinical implications.

Methods : We investigated expression profiles of 770 pan-cancer immune related genes using the nCounter mRNA expression assay (NanoString®) from paraffin-embedded tumor tissues in 200 patients diagnosed as TNBC who received curative surgery at Samsung Medical Center from 2000 to 2004. We analyzed the relationship between stage adjusted level of gene expressions and patients' survival outcomes using Cox regression model.

Results: Of 770 genes, 186 genes were selected from univariate analysis with clinical stage adjustment. In multivariate analysis using Cox regression, expressions of CD1B, CD45, CD53, CT45A1, GTF3C1, IL11RA, IL1RN, LRRN3, MAPK1, NEFL, PRKCE, SPACA3 and RANKL were associated with distant recurrence free survival (p<0.05, respectively). Among these 13 genes, expression of MAPK1, NEFL, CD45, SPACA3 and RANKL were correlated with favorable outcome in terms of distant recurrence free survival (p<0.05, respectively). In terms of overall survival, C3, IL1RL1, IL1RN, IL7 and PRKCE were associated with poor prognosis (p<0.05, respectively) and expression of SAA1 CXCL9 and RANKL resulted in favorable outcome (p<0.05, respectively).

Table 1ParameterParameter EstimateStandard Errorp-valueHazard Ratio95% Confidence Interval(a) distant recurrence free survival     Stage2.487350.680570.000312.0293.169, 45.661CD1B1.141910.2753<.00013.1331.826, 5.374CD531.531650.34851<.00014.6262.336, 9.159CT45A10.426110.134210.00151.5311.177, 1.992GTF3C11.193110.579720.03963.2971.059, 10.271IL11RA1.671120.461750.00035.3182.151, 13.146IL1RN0.980280.24657<.00012.6651.644, 4.321LRRN31.424170.28742<.00014.1542.365, 7.297MAPK1-0.542740.258240.03560.5810.35, 0.964NEFL-1.12170.335610.00080.3260.169, 0.629PRKCE2.378340.49659<.000110.7874.076, 28.549CD45-2.736780.43154<.00010.0650.028, 0.151SPACA3-0.745930.272270.00610.4740.278, 0.809RANKL-1.288920.2976<.00010.2760.154, 0.494(b) overall survival     Stage1.359280.497810.00633.8931.468, 10.329C30.329830.150350.02831.3911.036, 1.867CXCL9-0.379190.100680.00020.6840.562, 0.834IL1RL10.679360.262940.00981.9731.178, 3.303IL1RN0.437130.172370.01121.5481.104, 2.171IL70.507280.206250.01391.6611.109, 2.488PRKCE0.835340.272910.00222.3061.35, 3.936SAA1-0.564250.13449<.00010.5690.437, 0.74RANKL-0.604990.234510.00990.5460.345, 0.865

Conclusion: High expression of IL1RN, PRKCE were associated with short distant recurrence free survival and overall survival in patients with TNBCs who received curative surgery. In contrast, RANKL expression resulted in prolonged distant recurrence free survival and overall survival.

Citation Format: Kim J-Y, Jung HH, Lim JE, Cho EY, Lee SK, Yu JH, Lee JE, Kim SW, Nam SJ, Park YH, Ahn JS, Im Y-H. Prognostication of immune related gene expression in patients with triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-30.

Abstract P2-08-52: A predictive model for distant metastasis in breast cancer patients using machine learning

Introduction

Tumor metastasis is a major clinical challenge accounting for the vast majority of cancer related deaths.In previous studies, prediction of distant metastasis was based on subtypes,clinical status and sometimes gene expression were used however clinical application was difficult.

In this study, we develop the easy to use prediction tool for distant metastasis using clinical characteristics and gene profiles which came from CancerSCANTM, Next Generation Sequencing based targeted-sequencing platform designed at Samsung Medical Center(SMC).

Methods

We performed a retrospective chart review of 326 breast cancer patients who underwent surgery and CancerSCAN TM between Jan 2001 and Dec 2014 at SMC. Median follow up period was 83 months (Range 1˜190). Cancer scanTM cover 381 genes but 27 genes and 34 occasions (loss of function, mutation or copy number variation) were selected for analysis through gradient boosting and Wilcoxon Signed rank test. Azure Machine Learning is a cloud service that enables the execution of machine learning processes.This was accomplished using the steps of (1) edit the data, (2) split the data, (3) train the model, (4) score the model, and (5) evaluate the model. We split the modeling data into training and testing sets using a randomized 50–50 split. Two-class Decision Forest method was used. After deploying the Azure ML predictive model as a web service, we used a Representational State Transfer application programming interface to send data and obtained predictions in real-time.

Results

No distant metastasis group and distant metastasis group consisted of 267 and 59 patients, respectively. HR-/HER2+ and 50 years old and over patients were higher in metastasis group (p-value = 0.003 and p-value = 0.000). Nuclear grade 3 and N2,3 were higher in metastasis group (p-value = 0.010 and p-value = 0.000, p-value = 0.001 respectively). Stage III was also higher in metastasis group (p-value = 0.000). Among 59 patients with distantmetastasis, multiple sites metastasis was 21 cases (35.6%) and then lung metastasis was 19 cases (32.2%). In the 21 cases of multiple sites metastasis, triple sites was 6 cases (28.6%) and double sites was 15 cases (71.4%). PIK3CA mutation was the most frequent gene variation in all patients (34.5% of no metastasis group and 27.1% of metastasis group) but there was no difference between two groups(p-value = 0.278). BRCA 1 loss of function and BRCA2 loss of function were more frequent in metastasis group than no metastasis group(p-value = 0.033 and p-value = 0.024, respectively) but total counts was too small. We assessed the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for predictive value. The AUC of ROC curve was 1.000 and also accuracy, precision, recall were 1.000. In addition, we conducted internal validation using 83 patients during 2015. When we applied a 0.5 threshold value with our predictive model, true negative was 81 and true positive was 2 among 83 patients. Finally, the accuracy of validation was 1.000.

Conclusion

Our predicted model could represent a useful and easy-to-access tool for the selection of patients with distant metastasis. After additional evaluation with large data and external validation, worldwide use of our model could be expected.

Citation Format: Kim I, Choi HJ, Ryu JM, Lee SK, Yu JH, Kim SW, Nam SJ, Seo SW, Lee JE. A predictive model for distant metastasis in breast cancer patients using machine learning [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-52.

Abstract PD5-08: Neoadjuvant chemotherapy alters the genomic landscape and immune microenvironment of breast cancers

Understanding how standard-of-care drug treatments affect tumor intrinsic biology and microenvironment is critical for elucidating drug resistance mechanisms and developing better combination therapies as well as new therapies. To characterize the effects of neoadjuvant chemotherapy (NAC) on the genome, transcriptome and tumor infiltrating leukocytes (TILs), we have conducted whole exome and whole transcriptome sequencing of a large longitudinal breast cancer cohort consisting of 146 cases and 281 paired tumor samples. In total, 52 (38%) patients achieved pathologic complete response (pCR) while 85 patients (62%) had residual disease with standard chemotherapy regimen. Tumor biopsies were collected for each patient at three time points – pre-treatment, three weeks after the first cycle of anthracycline and cyclophosphamide (AC) and at the time of surgery after 3 more cycles of AC followed by 4 cycles of taxane or taxane plus Herceptin in case of HER2+ subtype. We detected 5,955 protein-altering somatic mutations affecting 4,414 genes in pretreatment samples and 502 acquired mutations in surgery samples affecting 477 genes including 19recurrently mutated genes such as TP53 and NOTCH1. Across all subtypes, 4,346 genes were differentially expressed (DE) following NAC treatment and significantly enriched in pathways such as cell cycle, ER signaling, PI3K/mTOR, immune and metabolism. Expression-based virtual microdissection analysis indicated that NAC treatment induced an increase in the fractions of stromal and adjacent normal tissue compartment, consistent with observed reduction in tumor cellularity. To assess the NAC induced changes in the molecular landscape of these tumors, we compared molecular features including gene expression signatures, mutation prevalence and copy number alteration between three time points while adjusting for confounding effects of molecular subtype and tumor cellularity. We found that NAC induced dynamic changes in gene expression signatures associated with proliferation and immunomodulatory treatment response. We further validated the observed pattern of change in TILs through histopathology and digital imaging analyses. In pretreatment tumors, 116 genes were DE between patients with pCR vs. those with residual disease with significant enrichment in immune/inflammatory pathways. Further, pre-treatment TIL levels were found to be significantly associated with pCR, echoing previous reports in breast cancers that implicated anti-tumor immunity in mediating the efficacy of chemotherapies. Our analyses also revealed associations between NAC response and baseline genomic attributes such as genomic alterations that affect DNA damage repair pathways. Taken together, these results suggest that NAC induced a multitude of changes on the genomic landscape and immune microenvironment of breast cancers, some of which point to combination strategies with immunomodulatory therapies and therapies that target DNA damage repair.

Citation Format: Kan Z, Lal S, Ding Y, Lee JE, Lee S-H, Lee SK, Yu JH, Choi Y-l, Kim SW, Nam SJ, Kim J-Y, Ram S, Powell E, Ching K, Cho SY, Bonato V, Deng S, Park W-Y, Rejto P, Bienkowska J, Park Y-H. Neoadjuvant chemotherapy alters the genomic landscape and immune microenvironment of breast cancers [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD5-08.

Abstract P1-15-18: Not presented

This abstract was not presented at the conference.

Citation Format: Choi HJ, Kim SW, Ryu JM, Kim I, Nam SJ, Yu J, Lee SK, Lee JE. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-18.

Abstract P2-08-29: The impact of time interval between diagnosis and surgery in each type and stage of breast cancer

Background: There are many factors that might contribute to the delay of surgery in patients with breast cancer. Previous studies investigate the influence of delay of surgery, but they reported inconsistent results. The purpose of this study was to evaluate the impact of time of surgery on prognosis of breast cancer.

Methods: We performed a retrospective review of the patients with breast cancer, who received surgery between 1992 and 2009, by using data from Korea Breast Cancer Society Registry. Kaplan-Meier survival analysis and Cox regression model were used to evaluate the impact of time to surgery in breast cancer and subgroup analyses were performed for each disease stage and molecular subtype.

Result: A total 14727 patients were included for analysis. Delay of surgery more than 31 days was associated with worse survival for breast cancer [hazard ratio (HR) = 2.16; 95% confidence interval (CI), 1.936-2.408, p<0.001]. Subgroup analyses revealed that over 31 days of surgical delay were significantly associated with worse survival in hormone receptor positive and HER-2 negative (p<0.001), hormone receptor positive and HER-2 positive (p<0.001), hormone receptor negative and HER-2 positive (p<0.001), triple negative (p<0.001) and stage II, III breast cancer patients (p<0.001).

Conclusion: Surgical delay of more than 31 days were independent risk factors for worse outcome of breast cancer in each molecular subtype and breast cancer group except stage 0 and I. Although preoperative evaluation is required, surgical delay should be shortened to enhance survival of breast cancer, especially in patients with tumor size more than 2cm or presence of lymph node metastasis.

Citation Format: Kim J-M, Choi HJ, Kim I, Ryu JM, Yu J, Lee JE, Kim SW, Nam SJ, Lee SK. The impact of time interval between diagnosis and surgery in each type and stage of breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-29.

Bromopyrrole Alkaloids from the Sponge Agelas kosrae

Two new sceptrin derivatives (1,2) and eight structurally-related known bromopyrrole-bearing alkaloids were isolated from the tropical sponge Agelas kosrae. By a combination of spectroscopic methods, the new compounds, designated dioxysceptrin (1) and ageleste C (2), were determined to be structural analogs of each other that differ at the imidazole moiety. Dioxysceptrin was also found to exist as a mixture of α-amido epimers. The sceptrin alkaloids exhibited weak cytotoxicity against cancer cells. Compounds 1 and 2 also moderately exhibited anti-angiogenic and isocitrate lyase-inhibitory activities, respectively.

The Dominant Role of Forkhead Box Proteins in Cancer

Forkhead box (FOX) proteins are multifaceted transcription factors that are significantly implicated in cancer, with various critical roles in biological processes. Herein, we provide an overview of several key members of the FOXA, FOXC, FOXM1, FOXO and FOXP subfamilies. Important pathophysiological processes of FOX transcription factors at multiple levels in a context-dependent manner are discussed. We also specifically summarize some major aspects of FOX transcription factors in association with cancer research such as drug resistance, tumor growth, genomic alterations or drivers of initiation. Finally, we suggest that targeting FOX proteins may be a potential therapeutic strategy to combat cancer.

Coculture of Marine Streptomyces sp. With Bacillus sp. Produces a New Piperazic Acid-Bearing Cyclic Peptide

Microbial culture conditions in the laboratory, which conventionally involve the cultivation of one strain in one culture vessel, are vastly different from natural microbial environments. Even though perfectly mimicking natural microbial interactions is virtually impossible, the cocultivation of multiple microbial strains is a reasonable strategy to induce the production of secondary metabolites, which enables the discovery of new bioactive natural products. Our coculture of marine Streptomyces and Bacillus strains isolated together from an intertidal mudflat led to discover a new metabolite, dentigerumycin E (1). Dentigerumycin E was determined to be a new cyclic hexapeptide incorporating three piperazic acids, N-OH-Thr, N-OH-Gly, β-OH-Leu, and a pyran-bearing polyketide acyl chain mainly by analysis of its NMR and MS spectroscopic data. The putative PKS-NRPS biosynthetic gene cluster for dentigerumycin E was found in the Streptomyces strain, providing clear evidence that this cyclic peptide is produced by the Streptomyces strain. The absolute configuration of dentigerumycin E was established based on the advanced Marfey's method, ROESY NMR correlations, and analysis of the amino acid sequence of the ketoreductase domain in the biosynthetic gene cluster. In biological evaluation of dentigerumycin E (1) and its chemical derivatives [2-N,16-N-deoxydenteigerumycin E (2) and dentigerumycin methyl ester (3)], only dentigerumycin E exhibited antiproliferative and antimetastatic activities against human cancer cells, indicating that N-OH and carboxylic acid functional groups are essential for the biological activity.

A novel selenonucleoside suppresses tumor growth by targeting Skp2 degradation in paclitaxel-resistant prostate cancer

Prostate cancer (PC) is the most common disease in men over age 50, and its prevalence rate has been gradually increasing since 1980. Taxane-derived anticancer agents are the primary agents used to treat metastatic prostate cancer patients; however, the side effects and acquired drug resistance limit the success of these therapies. Because there is no specific treatment for paclitaxel-resistant prostate cancer, it is necessary to develop new targets and therapeutic strategies to overcome the acquired resistance. In this study, the antitumor activity of a novel selenonucleoside (4'-selenofuranosyl-2,6-dichloropurine, LJ-2618), a third-generation nucleoside, and its plausible mechanisms of action in paclitaxel-resistant prostate cancer (PC-3-Pa) cells were investigated. The established PC-3-Pa cells exhibited over 100-fold resistance against paclitaxel compared to the paclitaxel-sensitive PC-3 cells. LJ-2618, however, effectively inhibited the proliferation of both cell lines with similar IC₅₀ values in vitro. In PC-3-Pa cells, the activated PI3K/Akt signaling pathway was suppressed by LJ-2618 treatment. In addition, Skp2 was found to be over-expressed in paclitaxel-resistant cells, and the transfection of Skp2 siRNA recovered the sensitivity of paclitaxel in PC-3-Pa cells. Furthermore, LJ-2618 significantly down-regulated Skp2 expression in PC-3-Pa cells by promoting degradation and inducing destabilization of Skp2, which triggers G₂/M cell cycle arrest. In a xenograft mouse model implanted with PC-3-Pa cells, LJ-2618 (3 or 10 mg/kg) effectively inhibited tumor growth with the enhancement of Skp2 degradation and induction of p27 expression in tumor tissues. These findings suggest that LJ-2618 may have potential for overcoming paclitaxel resistance via promoting Skp2 degradation and stabilizing p27 expression in PC-3-Pa cells. Therefore, the novel selenonucleoside LJ-2618 may lead to the development of a new treatment strategy for patients with paclitaxel-resistant, castration-resistant prostate cancer.

Transcatheter arterial embolization for iatrogenic bleeding after endoscopic ultrasound-guided pancreaticobiliary drainage

PURPOSE

The purpose of this study was to report the incidence of massive bleeding after endoscopic ultrasound-guided transmural pancreaticobiliary drainage (EUS-TPBD) and the clinical outcomes in patients with this condition treated with transcatheter arterial embolization (TAE).

PATIENTS AND METHODS

We performed a 9-year retrospective analysis of 797 EUS-TPBD procedures (excluding gallbladder or pseudocysts) in 729 patients. Among them, twelve (12/729, 1.65%) patients were referred for TAE to manage active bleeding adjacent to the TPBD sites. There were 8 men and 4 women with a mean age of 66.1 years±13.4 (SD) (range: 45-89 years). The clinical and procedure data of these 12 patients were reviewed.

RESULTS

Thirteen TAE procedures in 12 patients were performed. The bleeding sites were the left hepatic artery (n=7), the right hepatic artery (n=3), the left gastric artery (n=1), the left accessory gastric artery (n=1) and gastroduodenal artery (n=1). TAE was performed with gelatin sponge particles (n=1), coil (n=1) and n-butyl-2 cyanoacrylate with/without coils (n=11), with technical and clinical success rates of 100% (13/13) and 85% (11/13), respectively. Re-bleeding following embolization with gelatin sponge particles occurred in one patient. Procedure-related ischemic hepatitis was observed in another patient with pancreatic cancer with portal vein involvement.

CONCLUSION

On the basis of our results, TAE using n-butyl-2 cyanoacrylate seems safe and effective for the treatment of bleeding after EUS-TPBD procedures. When the portal vein is compromised, TAE of the hepatic artery can cause ischemic liver damage.

Abstract 4407: Targeting BMP4 and miR-139-5p in EGFR-mutant non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) cells with harboring EGF receptor (EGFR) mutations are sensitive to EGFR tyrosine kinase inhibitors (EGFR-TKIs). Recent studies suggest that bone morphogenetic proteins (BMPs) and microRNAs (miRNAs) might act as oncogenes or suppressors in tumor microenvironment. We identified the potential roles of BMPs and miRNAs involved in EGFR TKIs resistance by analyzing datasets from a pair of NSCLC-sensitive and NSCLC-resistant cells. BMP4 was found to be significantly over-expressed in EGFR-TKI resistant cells and its underlying mechanism was highly associated with induction of energy metabolism for cancer cells through modulating Acyl-CoA synthetase long-chain family member 4. In addition, miR-139-5p was found to be importantly down-regulated in the resistant NSCLC cells. The combination of miR-139-5p and yuanhuadine, a natural product-derived antitumor agent, synergistically suppressed the BMP4 expression in the resistant cells. We furthermore confirmed that LDN-193189, a small molecule BMP receptor 1 inhibitor inhibited the tumor growth in a xenograft nude mouse model implanted with drug resistant cells. These findings suggest a role of BMP4-mediated tumorigenesis in the progression of acquired drug resistance in EGFR-mutant NSCLC cells.

Key words: microRNAs, bone morphogenetic proteins, drug resistance, metabolism, EGFR-TKIs, NSCLC.

Acknowledgements

This study was funded by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2015R1D1A1A02062012).

Citation Format: Duc-Hiep Bach, Thi-Thu-Trang Luu, Dong-Hwa Kim, Yong Jin An, Hyen Joo Park, Sunghyouk Park, Sang Kook Lee. Targeting BMP4 and miR-139-5p in EGFR-mutant non-small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4407.

Anti-proliferative Effect of 15,16-Dihydrotanshinone I Through Cell Cycle Arrest and the Regulation of AMP-activated Protein Kinase/Akt/mTOR and Mitogen-activated Protein Kinase Signaling Pathway in Human Hepatocellular Carcinoma Cells

Background

15,16-dihydrotanshinone I (DHTS) is a natural abietane diterpenoid that is mainly found in the roots of Salvia miltiorrhiza Bunge (Labiatae). DHTS exhibits a potential anti-proliferative effect in various human cancer cells. However, the mechanisms of action of DHTS as an anti-cancer agent have not been fully elucidated. Therefore, the present study investigated the anti-cancer effect of DHTS in terms of cell cycle regulation and the regulation of the AMP-activated protein kinase (AMPK)/Akt/mTOR signaling pathway in SK-HEP-1 human hepatocellular carcinoma cells.

Methods

The anti-proliferative effects of DHTS were evaluated by the sulforhodamine B assay in SK-HEP-1 cells. Cell cycle distribution was analyzed by flow cytometry. The elucidation of mechanisms of action such as the AMPK/AKT/mTOR and mitogen-activated protein kinase (MAPK) pathway was assessed by Western blot analysis.

Results

DHTS showed a significant anti-proliferative activity against SK-HEP-1 cells. DHTS induced cell cycle arrest in the G0/G1 phase, which was mediated by downregulation of cyclin D1, cyclin A, cyclin E, CDK4, CDK2, c-Myc and p-Rb expression and with increased expression of the CDK inhibitor p21. DHTS also activated the AMPK signaling. In addition, DHTS downregulated the Akt/mTOR and MAPK signaling pathways.

Conclusions

Our results suggest that the anti-proliferative activity of DHTS might be associated with the induction of G0/G1 phase cell cycle arrest and regulation of AMPK/Akt/mTOR and MAPK signaling pathways in SK-HEP-1 cells.

Cyclopeptides from the Sponge Stylissa flabelliformis

Three new cyclopeptides, phakellistatins 20-22 (1-3), as well as 10 known cyclopeptides of the same structural class were isolated from the tropical sponge Stylissa flabelliformis. By a combination of chemical and spectroscopic methods, the structures of the new compounds were determined to be an epimeric mixture of cycloheptapeptides (1) and two epimeric cyclodecapeptides (2 and 3) related to the phakellistatins. The cyclopeptides were evaluated for in vitro cytotoxicity against a variety of cancer cell lines, and compounds 2 and 3 exhibited significant activity.

Design, synthesis and anticancer activity of fluorocyclopentenyl-purines and - pyrimidines

Based on the potent anticancer activity of 6'-fluorocyclopentenyl-cytosine 2b in phase IIa clinical trials for the treatment of gemcitabine-resistant pancreatic cancer, we carried out a systematic structure-activity relationship study of 6'-fluorocyclopentenyl-pyrimidines 3a-i and -purines 3j-o to discover novel anticancer agents. We also synthesized the phosphoramidate prodrug 3p of adenine derivative 1b to determine if the anticancer activity depended on the inhibition of DNA and/or RNA polymerase in cancer cells and/or on the inhibition of S-adenosylhomocysteine (SAH) hydrolase. All of the synthesized pyrimidine nucleosides exhibited much less potent anticancer activity in vitro than the cytosine derivative 2b, acting as RNA and/or DNA polymerase inhibitor, indicating that they could not be efficiently converted to their triphosphates for anticancer activity. Among all the synthesized purine nucleosides, adenine derivative 1b and N⁶-methyladenine derivative 3k showed potent anticancer activity, showing equipotent inhibitory activity as the positive control, neplanocin A (1a) or Ara-C. However, the phosphoramidate prodrug 3p showed less anticancer activity than 1b, indicating that it did not act as a RNA and/or DNA polymerase inhibitor like 2b. This result also demonstrates that the anticancer activity of 1b largely depends on the inhibition of histone methyltransferase, resulting from strong inhibition of SAH hydrolase. The deamination of the N⁶-amino group, the addition of the bulky alkyl group at the N⁶-amino group, or the introduction of the amino group at the C2 position almost abolished the anticancer activity.

Depsidomycins B and C: New Cyclic Peptides from a Ginseng Farm Soil-Derived Actinomycete

LC/MS-based chemical profiling of a ginseng farm soil-derived actinomycete strain, Streptomyces sp. BYK1371, enabled the discovery of two new cyclic heptapeptides, depsidomycins B and C (1 and 2), each containing two piperazic acid units and a formyl group at their N-terminus. The structures of 1 and 2 were elucidated by a combination of spectroscopic and chemical analyses. These new compounds were determined to possess d-leucine, d-threonine, d-valine, and S-piperazic acid based on the advanced Marfey's method and a GITC (2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate) derivatization of their hydrolysates, followed by LC/MS analysis. Depsidomycins B and C displayed significant antimetastatic activities against metastatic breast cancer cells (MDA-MB-231).

The Dual Role of Bone Morphogenetic Proteins in Cancer

Bone morphogenetic proteins (BMPs) are a diverse class of molecules with over 20 growth factor proteins that belong to the transforming growth factor-β (TGF-β) family and are highly associated with bone formation and disease development. Aberrant expression of various BMPs has been reported in several cancer tissues. Biological function studies have elicited the dual role of BMPs in both cancer development and suppression. Furthermore, a variety of BMP antagonists, ligands, and receptors have been shown to reduce or enhance tumorigenesis and metastasis. Knockout mouse models of BMP signaling components have also revealed that the suppression of BMP signaling impairs cancer metastasis. Herein, we highlight the basic clinical background and involvement of BMPs in modulating cancer progression and their dynamic interactions (e.g., with microRNAs) in the tumor microenvironment in addition to their mutations and roles in chemoprevention. We also suggest that BMPs should be considered a powerful putative therapeutic target in tumorigenesis and bone metastasis.

Targeting Nicotinamide N-Methyltransferase and miR-449a in EGFR-TKI-Resistant Non-Small-Cell Lung Cancer Cells

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are used clinically as target therapies for lung cancer patients, but the occurrence of acquired drug resistance limits their efficacy. Nicotinamide N-methyltransferase (NNMT), a cancer-associated metabolic enzyme, is commonly overexpressed in various human tumors. Emerging evidence also suggests a crucial loss of function of microRNAs (miRNAs) in modulating tumor progression in response to standard therapies. However, their precise roles in regulating the development of drug-resistant tumorigenesis are still poorly understood. Herein, we established EGFR-TKI-resistant non-small-cell lung cancer (NSCLC) models and observed a negative correlation between the expression levels of NNMT and miR-449a in tumor cells. Additionally, knockdown of NNMT suppressed p-Akt and tumorigenesis, while re-expression of miR-449a induced phosphatase and tensin homolog (PTEN), and inhibited tumor growth. Furthermore, yuanhuadine, an antitumor agent, significantly upregulated miR-449a levels while critically suppressing NNMT expression. These findings suggest a novel therapeutic approach for overcoming EGFR-TKI resistance to NSCLC treatment.

Esculetin suppresses tumor growth and metastasis by targeting Axin2/E-cadherin axis in colorectal cancer

Colorectal cancer (CRC) is the most common malignant disease worldwide due to its metastasis via the epithelial-mesenchymal transition (EMT) process. E-cadherin and Wnt signaling are emerging as potential targets for suppressing the EMT. In this context, Axin2 has been recognized as a negative regulator that inhibits glycogen synthase kinase 3β (GSK3β)-mediated degradation of Snail1, a transcriptional repressor of E-cadherin. However, Axin2 can also impede Wnt signaling via β-catenin degradation. Therefore, Axin2 may serve as either a promoter or suppressor of tumors, and the effects of its inhibition on the cell proliferation and metastasis of CRC require further elucidation. Here, esculetin (ES), a coumarin, was found to have the most potential effects on both β-catenin-responsive transcriptional and E-cadherin promoter activities. ES also showed anti-proliferative and anti-invasive activities in CRC cells. Mechanistically, Axin2 suppression by ES contributed to E-cadherin-mediated Wnt signaling inhibition. Moreover, the ability of ES to inhibit tumor growth and metastasis via Axin2 suppression was further supported in an HCT116-implanted orthotopic mouse model. Collectively, these findings suggest that targeting the Axin2/E-cadherin axis by ES may be an attractive therapeutic strategy for the treatment of metastatic CRC.

Abstract P6-09-08: Identification of ESR1 mutation in breast cancers using targeted ultra-deep sequencing data analysis

Introduction: Estrogen Receptor 1 (ESR1) gene encodes an estrogen receptor, which regulates cell proliferation and promotes tumor progression in estrogen receptor(ER)-positive breast cancer (BC). Therefore, endocrine therapy that inhibiting ER downstream signal, is the most effective treatment strategy in ER-positive BC. However, about 25% of patients with primary disease and almost all patients with metastases will present with or eventually develop endocrine resistance. And genetic alteration of ESR1 is now identified as the endocrine resistance mechanism. However, a few data from clinical trials or public data base exists and could not reflect real world clinic. Therefore, we aimed to identify the frequency and type of ESR1 genetic alterations in BCs through this large scaled study.

Methods: We performed targeted ultra-deep sequencing (CancerSCAN™) using BC tissue specimens. This sequencing was covered entire coding area of ESR1 gene and also detected copy number alteration and translocation of ESR1.

Results: Targeted ultra-deep sequencing of ESR1 was performed using 618 BC tissues. Of 618 tissue samples, 253(40.9%) were MBCs, 362(58.6%) were early BCs (EBCs) and 3 were not identified. In terms of subtypes, 220 ER-positive BCs, 122 ER-positive and HER2-positive BCs, 119 HER2-positive and 153 triple-negative BCs (TNBCs) were included. BCs from patients under 40 year-old were 277(44.8%)(Median: 43.0, range: 23.5 -75.6). ESR1 genetic alterations were identified in 21 BCs (5 EBCs and 16 MBCs). In EBCs, 3 cases were observed in TNBCs and 2 cases were in ER-positive BCs (2.6% and 1.2%, respectively). All five EBC were treatment naïve status. Of 16 cases of ESR1 alterations in MBCs, 10 cases of ESR1 alterations were detected in ER-positive BCs (17.6%), 5cases in ER and HER2-positive BCs(6.7%) and 1 in HER2-positive BCs (1.2%). All ER-positive MBCs were treated with more than one line of endocrine therapy. Most commonly detected genetic alteration was single nucleotide variant (SNV) (15 of 21, 71.4%). Thirteen were in ligand binding domain and two cases occurred in activation function-1 (AF-1) domain (P79A and G145S). D538G and V392I were most frequently mutated loci followed by Y537N (3, 3 and 2 cases, respectively) and only metastatic ER-positive BCs harbored ESR1 activating mutation. Four copy number (CN) amplification in 2 ER-positive and 2 ER and HER2-positive BCs, one CN deletion in TNBC and one ESR1 fusion in ER and HER2-positive BC were also detected (19.0%, 4.8% and 4.8%, respectively). In frame ESR1 fusion was occurred between ESR1 and NPHS1 genes.

Conclusion: In this experimental study, ESR1 genetic alterations were frequently detected in ER-positive MBC but ER-negative or EBC also harbored. The type of genetic alterations varied including SNVs, CN alterations and translocation and ESR1-NPHS1 fusion is the novel genetic alteration that has not been reported. To identify the role of ESR1 genetic alteration in ER-negative BCs and novel translocation, further functional validation would be warranted (Clinical trials.gov Number :NCT02591966).

Citation Format: Kim J-Y, Park K, Park W-Y, Nam SJ, Kim SW, Lee JE, Lee SK, Jung HH, Yu JH, Ahn JS, Im Y-H, Park YH. Identification of ESR1 mutation in breast cancers using targeted ultra-deep sequencing data analysis [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-09-08.

Abstract P1-07-25: Differences among young breast cancer patients based on subtype: A study from the Korean Breast Cancer Society – Running head: Do breast cancers in 20s have worse prognosis than 30s?

Purpose Numerous studies demonstrated that breast cancer in young women (BCY) has unfavorable prognostic features and unfavorable subtype. However, there were few studies to evaluate the effect on the prognosis of breast cancer according to the subtype disparities by age especially BCY. We analyzed breast cancer mortality stratified tumor subtype according to age among the patients with less than 50 year-old. Patients and Methods Data obtained from the Korean Breast Cancer Society Registry (KBCSR), patients diagnosed with invasive breast cancer were retrospectively between 2003 and 2010. We excluded patients with male breast cancer, underwent neoadjuvant chemotherapy, distant metastasis or inflammatory breast cancer at presentation, and other histopathology except invasive ductal or invasive lobular carcinoma. We also excluded patients with lack of immunohistochemistry data and short-term follow-up duration (<12 months). Results We identified 37,865 patients, and excluded by study protocol. Among those, 30,793 patients with breast cancer for eligible for analysis, 793 (2.6%) were 20-29 years and 8,926 (28.8%) were 30-39 years of age. Median follow-up duration was 84 months. Mean age was 42.4 years old. Younger patients with breast cancer were more likely to have advanced stage, higher nuclear grade, present lymphovascular invasion, and more likely to be unfavorable subtype such as triple negative breast cancer (TNBC)

Table 1. Baseline Characteristics Age at Presentation 20-29, N(%)30-39, N(%)40-49, N(%)P-valueOverall793 (2.6)8,133 (26.4)21,867 (71.0) Pathologic stage   <.0001I295 (37.2)2,928 (36.0)9,288 (42.5) II373 (47.0)3,644 (44.8)9,078 (41.5) III119 (15.0)1,442 (17.7)3,211 (14.7) Family history   <.0001Yes81 (10.2)674 (8.3)1,391 (6.4) No712 (89.8)7,459 (91.7)20,476 (93.6) Nuclear grade   <.0001Low85 (10.2)941 (11.6)3,824 (17.5) Intermediate288 (36.3)3,340 (41.1)9,688 (44.3) High331 (41.7)3,165 (38.9)6,650 (30.4) LVI   <.0001Yes249 (31.4)2,840 (34.9)6,711 (30.7) No433 (54.6)4,367 (53.7)13,005 (59.5) Subtype   <.0001Luminal A314 (39.6)3,529 (43.4)11,716 (53.6) Luminal B190 (24.0)1,895 (23.3)4,775 (21.8) Her-252 (6.6)724 (8.9)1,723 (7.9) TNBC237 (29.8)1,895 (24.4)3,653 (16.7) HER-2, human epidermal growth factor-2; TNBC, triple negative breast cancer

. Patients with younger age group showed worse prognosis than patients with older age patients. In multivariate analysis for overall survival, as patients were younger group, hazard ratio was increased, and the patients with TNBC showed higher HR than HER-2, Luminal B, and Luminal A subtype (P< .0001, P< .0001, P< .0001, and P< .0001, respectively). Stratified by subtype, luminal subtype showed significant worse prognosis as the age group was younger, while as, Her-2 and TNBC subtype showed no significantly difference by the age group. Conclusion Patients with 20s breast cancer showed unfavorable characteristics and worse prognosis than 30s and older aged group. Stratified by tumor subtype, breast cancer in 20s with luminal subtype showed worse prognosis, while as HER-2 and TNBC showed no significantly different compare to breast cancer in 30s.

Citation Format: Ryu JM, Yu J, Nam SJ, Kim I, Lee JE, Lee SK, Kim JM, Choi HJ, Kim SW. Differences among young breast cancer patients based on subtype: A study from the Korean Breast Cancer Society – Running head: Do breast cancers in 20s have worse prognosis than 30s? [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-25.

Correlation between extension-block K-wire insertion angle and postoperative extension loss in mallet finger fracture

INTRODUCTION

Extension-block pinning represents a simple and reliable surgical technique. Although this procedure is commonly performed successfully, some patients develop postoperative extension loss. To date, the relationship between extension-block Kirschner wire (K-wire) insertion angle and postoperative extension loss in mallet finger fracture remains unclear.

HYPOTHESIS

We aimed to clarify this relationship and further evaluate how various operative and non-operative factors affect postoperative extension loss after extension-block pinning for mallet finger fracture.

MATERIALS AND METHOD

A retrospective study was conducted to investigate a relationship between extension block K-wire insertion angle and postoperative extension loss. The inclusion criteria were: (1) a dorsal intra-articular fracture fragment involving 30% of the base of the distal phalanx with or without volar subluxation of the distal phalanx; and (2) <3 weeks delay from the injury without treatment. Extension-block K-wire insertion angle and fixation angle of the distal interphalangeal (DIP) joint were assessed using lateral radiograph at immediate postoperative time. Postoperative extension loss was assessed by using lateral radiograph at latest follow-up. Extension-block K-wire insertion angle was defined as the acute angle between extension block K-wire and longitudinal axis of middle phalangeal head. DIP joint fixation angle was defined as the acute angle between the distal phalanx and middle phalanx longitudinal axes.

RESULTS

Seventy-five patients were included. The correlation analysis revealed that extension-block K-wire insertion angle had a negative correlation with postoperative extension loss, whereas fracture size and time to operation had a positive correlation (correlation coefficient for extension block K-wire angle: -0.66, facture size: +0.67, time to operation: +0.60). When stratifying patients in terms of negative and positive fixation angle of the DIP joint, the independent t-test showed that mean postoperative extension loss is -3.67° and +4.54° (DIP joint fixation angles of <0° and ≥0°, respectively, P=0.024). When stratifying patients in terms of extension-block K-wire insertion angle (30°, 30°-40°, >40°), ANOVA showed significantly less postoperative extension loss for higher insertion angles (>40°) than for medium insertion angles (30°-40°). Mean postoperative extension loss difference between higher insertion angle (>40°) and medium insertion angle (30°-40°) was 11° (P=0.002).

DISCUSSION

Using an insertion angle of the extension-block K-wire of 40°-45° and a slightly hyperextended position of the DIP joint may help reducing postoperative extension loss.

LEVEL OF EVIDENCE

Therapeutic level III.