Yaewon Yang

Phase I study of random, healthy donor-derived allogeneic natural killer cell therapy in patients with malignant lymphoma or advanced solid tumors

Completely allogeneic NK cells could provide a ready source of antitumor activity. This preliminary clinical trial shows that such cells are well tolerated and have potential benefits for cancer patients by upregulating the host immune responses against cancer. Natural killer (NK) cells with mismatched killer cell immunoglobulin-like receptor–ligand pairs have shown efficacy and been proven safe in treatment of cancer patients. Ex vivo–expanded and highly activated NK cells (MG4101) had been generated under good manufacturing practice conditions, which demonstrated potent anticancer activity in vitro and in vivo in preclinical studies. The current phase I clinical trial was designed to evaluate safety and possible clinical efficacy of repetitive administrations of MG4101 derived from random unrelated healthy donors into patients with malignant lymphoma or advanced, recurrent solid tumors. The maximum dose (3 × 107 cells/kg, triple infusion) was tolerable without significant adverse events. Of 17 evaluable patients, 8 patients (47.1%) showed stable disease and 9 (52.9%) showed progressive disease. We also evaluated the capacity of MG4101 to influence host immune responses. Administration of MG4101 augmented NKG2D expression on CD8+ T cells and upregulated chemokines that recruit T cells. In contrast, administration of MG4101 reduced regulatory T cells and myeloid-derived suppressor cells and suppressed TGFβ production. In conclusion, administration of a large number of MG4101 cells was not only safe and feasible, but also exhibited efficacy in maintaining the effector arm of the host immune response. Cancer Immunol Res; 4(3); 215–24. ©2016 AACR.

AZD6738, A Novel Oral Inhibitor of ATR, Induces Synthetic Lethality with ATM Deficiency in Gastric Cancer Cells

Ataxia telangiectasia and Rad3-related (ATR) can be considered an attractive target for cancer treatment due to its deleterious effect on cancer cells harboring a homologous recombination defect. The aim of this study was to investigate the potential use of the ATR inhibitor, AZD6738, to treat gastric cancer. In SNU-601 cells with dysfunctional ATM, AZD6738 treatment led to an accumulation of DNA damage due to dysfunctional RAD51 foci formation, S phase arrest, and caspase 3–dependent apoptosis. In contrast, SNU-484 cells with functional ATM were not sensitive to AZD6738. Inhibition of ATM in SNU-484 cells enhanced AZD6738 sensitivity to a level comparable with that observed in SNU-601 cells, showing that activation of the ATM-Chk2 signaling pathway attenuates AZD6738 sensitivity. In addition, decreased HDAC1 expression was found to be associated with ATM inactivation in SNU-601 cells, demonstrating the interaction between HDAC1 and ATM can affect sensitivity to AZD6738. Furthermore, in an in vivo tumor xenograft mouse model, AZD6738 significantly suppressed tumor growth and increased apoptosis. These findings suggest synthetic lethality between ATR inhibition and ATM deficiency in gastric cancer cells. Further clinical studies on the interaction between AZD 6738 and ATM deficiency are warranted to develop novel treatment strategies for gastric cancer. Mol Cancer Ther; 16(4); 566–77. ©2017 AACR.

Anti‐tumor activity of the ATR inhibitor AZD6738 in HER2 positive breast cancer cells

Ataxia telangiectasia and Rad3‐related (ATR) proteins are sensors of DNA damage, which induces homologous recombination (HR)‐dependent repair. ATR is a master regulator of DNA damage repair (DDR), signaling to control DNA replication, DNA repair and apoptosis. Therefore, the ATR pathway might be an attractive target for developing new drugs. This study was designed to investigate the antitumor effects of the ATR inhibitor, AZD6738 and its underlying mechanism in human breast cancer cells. Growth inhibitory effects of AZD6738 against human breast cancer cell lines were studied using a 3‐(4,5‐dimethylthiazol‐2‐yl)−2,5‐diphenyltetrazolium bromide (methyl thiazolyl tetrazolium, MTT) assay. Cell cycle analysis, Western blotting, immunofluorescence and comet assays were also performed to elucidate underlying mechanisms of AZD6738 action. Anti‐proliferative and DDR inhibitory effects of AZD6738 were demonstrated in human breast cancer cell lines. Among 13 cell lines, the IC50 values of nine cell lines were less than 1 μmol/L using MTT assay. Two cell lines, SK‐BR‐3 and BT‐474, were chosen for further evaluation focused on human epidermal growth factor receptor 2 (HER2)‐positive breast cancer cells. Sensitive SK‐BR‐3 but not the less sensitive BT‐474 breast cancer cells showed increased level of apoptosis and S phase arrest and reduced expression levels of phosphorylated check‐point kinase 1 (CHK1) and other repair markers. Decreased functional CHK1 expression induced DNA damage accumulation due to HR inactivation. AZD6738 showed synergistic activity with cisplatin. Understanding the antitumor activity and mechanisms of AZD6738 in HER2‐positive breast cancer cells creates the possibility for future clinical trials targeting DDR in HER2‐positive breast cancer treatment.

Prognostic impact of AJCC response criteria for neoadjuvant chemotherapy in stage II/III breast cancer patients: breast cancer subtype analyses.

BackgroundNeoadjuvant chemotherapy (NAC) is a standard treatment for stage II/III breast cancer patients, and response to NAC is a useful prognostic marker. Since its introduction, 6–8 cycles of NAC has become the standard regimen to improve the outcome of these patients. The purpose of this study is to evaluate the prognostic impact of the American Joint Committee on Cancer (AJCC) response criteria and this tool’s usefulness in four different breast cancer subtypes.MethodsWe conducted a retrospective cohort study of clinical stage II/III breast cancer patients who received NAC of more than 6xa0cycles. Response after NAC and the clinicopathological factors were reviewed. AJCC response criteria for NAC were adopted from the AJCC Manual, 7th edition: complete response (CR), partial response (PR), and no response (NR).ResultsA total of 183 patients were enrolled; 22 (12.0xa0%), 123 (67.2xa0%), and 38 (20.8xa0%) patients showed CR, PR, and NR, respectively. The AJCC response was significantly associated with relapse-free survival (RFS) (Pu2009<u20090.001), whereas pathologic CR (pCR), the current gold standard for response evaluation for NAC, was not (Pu2009=u20090.140). AJCC response was a significant prognostic factor for RFS in all four breast cancer subtypes, namely luminal A (Pu2009=u20090.006), luminal B (Pu2009=u20090.001), HER-2 enriched (Pu2009=u20090.039), and triple-negative breast cancer (Pu2009=u20090.035).ConclusionsThe AJCC response criteria represent a simple and easily reproducible tool for response evaluation of NAC patients and a useful clinical prognostic marker for RFS. These criteria also have a prognostic impact in all four breast cancer subtypes, including luminal A in which pCR has a limited role.

CA19-9 or CEA Decline after the First Cycle of Treatment Predicts Survival in Advanced Biliary Tract Cancer Patients Treated with S-1 and Cisplatin Chemotherapy

Purpose While tumor markers (carbohydrate antigen 19-9 [CA 19-9] and carcinoembryonic antigen [CEA]) can aid in the diagnosis of biliary tract cancer, their prognostic role has not been clearly elucidated. Therefore, this study was conducted to evaluate the prognostic role of tumor markers and tumor marker change in patients with advanced biliary tract cancer. Materials and Methods Patients with pathologically proven metastatic or relapsed biliary tract cancer who were treated in a phase II trial of first-line S-1 and cisplatin chemotherapy were enrolled. Serum tumor markers were measured at baseline and after the first cycle of chemotherapy. Results Among a total of 104 patients, 80 (77%) had elevated baseline tumor markers (69 with CA 19-9 elevation and 40 with CEA). A decline ≥ 30% of the elevated tumor marker level after the first cycle of chemotherapy conferred an improved time to progression (TTP), overall survival (OS), and better chemotherapy response. Multivariate analysis revealed tumor marker decline as an independent positive prognostic factor of TTP (adjusted hazard ratio [HR], 0.44; p=0.003) and OS (adjusted HR, 0.37; p < 0.001). Subgroup analysis revealed similar results in each group of patients with CA 19-9 elevation and CEA elevation. In addition, elevated baseline CEA was associated with poor survival in both univariate and multivariate analysis. Conclusion Tumor marker decline was associated with improved survival in biliary tract cancer. Measuring tumor marker after the first cycle of chemotherapy can be used as an early assessment of treatment outcome.

Anti-tumor Effect of KX-01 Through Inhibiting Src Family Kinases and Mitosis

Purpose KX-01 is a novel dual inhibitor of Src and tubulin. Unlike previous Src inhibitors that failed to show clinical benefit during treatment of breast cancer, KX-01 can potentially overcome the therapeutic limitations of current Src inhibitors through inhibition of both Src and tubulin. The present study further evaluates the activity and mechanism of KX-01 in vitro and in vivo. Materials and Methods The antitumor effect of KX-01 in triple negative breast cancer (TNBC) cell lines was determined by MTT assay. Wound healing and immunofluorescence assays were performed to evaluate the action mechanisms of KX-01. Changes in the cell cycle and molecular changes induced by KX-01 were also evaluated. A MDA-MB-231 mouse xenograft model was used to demonstrate the in vivo effects. Results KX-01 effectively inhibited the growth of breast cancer cell lines. The expression of phospho-Src and proliferative-signaling molecules were down-regulated in KX-01-sensitive TNBC cell lines. In addition, migration inhibition was observed by wound healing assay. KX-01-induced G2/M cell cycle arrest and increased the aneuploid cell population in KX-01-sensitive cell lines. Multi-nucleated cells were significantly increased after KX-01 treatment. Furthermore, KX-01 effectively delayed tumor growth in a MDA-MB-231 mouse xenograft model. Conclusion KX-01 effectively inhibited cell growth and migration of TNBC cells. Moreover, this study demonstrated that KX-01 showed antitumor effects through the inhibition of Src signaling and the induction of mitotic catastrophe. The antitumor effects of KX-01 were also demonstrated in vivo using a mouse xenograft model.

Sequential spinal and intracranial dural metastases in gastric adenocarcinoma: A case report

Dural metastasis from primary gastric adenocarcinoma has been rarely reported, and its prognosis is very poor because it frequently leads to acute subdural hematoma. Here, we describe a case with sequential spinal and cranial dural metastases from gastric adenocarcinoma without subdural hematoma. A 43-year-old woman with gastric adenocarcinoma and well-controlled peritoneal carcinomatosis presented with back pain, right radiating leg pain, left facial palsy, and hearing loss. Magnetic resonance imaging of the spine and brain revealed dural masses at the lumbosacral junction with invasion to the L5 and S1 nerve roots and at the skull base with invasion to the internal auditory canal. She was treated with local radiotherapy, and her pain and neurologic symptoms improved after palliative radiotherapy. This is the first reported case of dural metastases of gastric adenocarcinoma of the spine and skull base but with a relatively indolent course and without subdural hematoma.

EGFR Mutation Status in Lung Adenocarcinoma-Associated Malignant Pleural Effusion and Efficacy of EGFR Tyrosine Kinase Inhibitors

Purpose Malignant pleural effusions (MPEs) are often observed in lung cancer, particularly adenocarcinoma. The aim of this study was to investigate epidermal growth factor receptor (EGFR) mutation status in lung adenocarcinoma-associated MPEs (LA-MPEs) and its correlation with efficacy of EGFR tyrosine kinase inhibitor (TKI) therapy. Materials and Methods Samples comprised 40 cell blocks of pathologically-confirmed LA-MPEs collected before the start of EGFR TKI therapy. EGFR mutation status was re-evaluated by peptide nucleic acid clamping and the clinical outcomes of EGFR TKI‒treated patients were analyzed retrospectively. Results EGFR mutations were detected in 72.5% of LA-MPE cell blocks (29/40). The median progression-free survival for patients with EGFR mutations in LA-MPEs was better than that for patients with wild-type EGFR (7.33 months vs. 2.07 months; hazard ratio, 0.486; 95% confidence interval, 0.206 to 1.144; p=0.032). The objective response rate (ORR) of 26 patients with EGFR mutations in LA-MPEs among the 36 patients with measurable lesions was 80.8%, while the ORR of the 10 patients with wild-type EGFR in LA-MPEs was 10% (p < 0.001). Among the 26 patients with EGFR mutations in LA-MPEs, the ORR of target lesions and LA-MPEs were 88.5% and 61.5%, respectively (p=0.026). Conclusion EGFR mutation status in cell blocks of LA-MPEs confirmed by pathologic diagnosis is highly predictive of EGFR TKI efficacy. For patients with EGFR mutations in LA-MPEs, the response to EGFR TKIs seems to be worse for pleural effusions than for solid tumors.

Abstract LB-107: Androgen receptor inhibitor enhances the antitumor effect of PARP inhibitor in breast cancer cells via modulation of DNA damage response

Introduction: Olaparib, a PARP inhibitor has produced promising antitumor efficacy in patients with BRCA mutation. However, cancers with BRCAness represent only a small proportion of breast cancer cases. To make olaparib useful to the broader cancer population, the development of new combinational strategies are required. The androgen receptor (AR) is expressed in 60∼70% of breast cancers regardless of ER status and has been proposed as a therapeutic target in breast cancers that retain AR. AR signaling was recently demonstrated to be a key regulator of the DNA damage response (DDR) in prostate cancer cells. AR inhibition increased cell death induced by DNA damage from cytotoxic insults. Based on these evidence, we hypothesized that AR inhibition using AZD3514, a novel AR inhibitor, would enhance the anti-tumor effect of PARP inhibitor in breast cancer cells by blocking DNA repair pathway. Materials and Methods: The cytotoxic assay, cell cycle analysis and western blotting were conducted to determine whether AZD3514, an AR inhibitor could enhance the anti-tumor effects of olaparib on breast cancer cells. The regulation of DDR activity by AZD3514 was accessed by the comet and IFA analysis. The molecular mechanism of DDR regulation by AZD3514 was also determined through gene knockdown experiments. These in vitro data were validated in vivo model as well. Results: AR inhibition had a minimal anti-proliferative effect on most of the breast cancer cell lines irrespective of the degree of AR expression levels as a monotherapy. However, AZD3514 downregulated the expressions of DDR molecules, including ATM and chk2 in some breast cancer cell lines. Breast cancer cell lines exhibited a various level of response of the combination treatment irrespective of their subtype as well as their AR expression levels. Co-targeting AR and PARP suppressed the proliferation and induced G2/M cell cycle arrest and apoptosis in MDA-MB-468 cells, but not that of MDA-MB-453 cells. Furthermore, AZD3514 treatment decreased the activity of ATM-chk2 axis resulting in the accumulation of DNA damage via compromising DDR activity in MDA-MB-468 cells. The results indicated that the mechanism underlying that AZD3514 enhances cellular sensitivity to olaparib would be through abrogation of the DNA DSB repair pathway in MDA-MB-468 cells. We also found that down-regulation of NKX3.1 expression correlated with suppressed activation of ATM-chk2 axis in MDA-MB-468 cells. In addition, the suppressed levels of NKX3.1 following AZD3514 treatment were a result of that AZD3514 induced TOPORS expression resulting in acceleration of NKX3.1 degradation. Finally, these in vitro findings were validated in a MDA-MB-468 xenograft model. Conclusions: Our data revealed that post-translational regulation of NKX3.1 by modulation of TOPORS expression following AZD3514 treatment induced ATM inactivation which can increase olaparib sensitivity in AR positive and TOPORS expressed breast cancer cells. This study firstly demonstrated the anti-tumor effect of AZD3514 in a combination with olaparib via compromising DDR activity in breast cancer cell lines as well as in a xenograft model. Our results provide a rationale for the future clinical trials of olaparib combined with AR inhibition in the treatment of breast cancers. Citation Format: Ahrum Min, Seock-Ah Im, Hyemin Jang, Seongyeong Kim, So Hyeon Kim, Yu Jin Kim, Debora Keunyoung Kim, Yaewon Yang, Koung Jin Suh, Kyung-Hun Lee, Tae-Yong Kim, Do-Youn Oh, Yung-Jue Bang. Androgen receptor inhibitor enhances the antitumor effect of PARP inhibitor in breast cancer cells via modulation of DNA damage response. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-107.

Abstract 2422: Pan-pim kinases inhibitor, AZD1208 suppresses tumor growth and synergistically interacts with an AKT inhibitor in gastric cancer cells

Introduction: Pim kinases are highly conserved serine/threonine kinases that control proliferation and survival pathways in cancer cells. Different expression patterns of each isoforms (Pim-1, Pim-2, and Pim-3) have been observed in various types of human cancer including gastric cancer. AZD1208 is a potent and selective inhibitor that affects all three isoforms of Pim. We investigated the effect of AZD1208 as a single agent or in combination with an Akt inhibitor on the growth and cell death in gastric cancer cells. Materials and Methods: The antitumor activity of AZD1208 with/without an Akt inhibitor was evaluated in a large panel of gastric cancer cell lines through growth inhibition assay. The underlying mechanism was also examined by western blotting, immunofluorescence assay (IFA), and cell cycle analysis. Results: Direct substrates of Pim kinases were downregulated by the treatment with AZD1208, but we could not find any reduction of cell viability in short-term cell cultures. In contrast, cell viability decreased significantly in long-term cultures. Light chain 3B (LC3B), a marker for autophagy, increased in sensitive cells in dose dependent manner with AZD1208 treatment, which suggest that the growth inhibition effect of AZD1208 was achieved through autophagy, but not through apoptosis. Moreover, we found that ATM and Chk2, two critical components of the DNA repair pathway, were activated in an AZD1208-resistant cell line. We also confirmed that the combination of an Akt inhibitor with AZD1208 produced a highly synergistic effect in gastric cancer cell lines. Conclusion: AZD1208 induced cell death through autophagy in gastric cancer cells. Additionally, the combination of AZD1208 with an Akt inhibitor shows synergistic antitumor effects. Citation Format: Miso Lee, Kyung-Hun Lee, Ahrum Min, Jungeun Kim, Seock-Ah Im, Seon-Gyeong Kim, Hyemin Jang, Yae-Won Yang, Tae-Yong Kim, Sae-Won Han, Do-Youn Oh, Tae-You Kim, Yung-Jue Bang. Pan-pim kinases inhibitor, AZD1208 suppresses tumor growth and synergistically interacts with an AKT inhibitor in gastric cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2422. doi:10.1158/1538-7445.AM2015-2422