Research

TRPM2 mediates distruption of autophagy machinery and correlates with the grade level in prostate cancer Abstract Purpose Transient receptor potential melastatin 2 (TRPM2), a calcium-permeable ion channel, is shown as a prognostic marker candidate in prostate cancer (PCa) and an important regulator of autophagy. We aimed to determine the changes in TRPM2 and autophagic–apoptotic gene expression levels in human prostate adenocarcinomas, and to investigate the affect of TRPM2 on autophagic pathways in PC-3 cell line. Methods Human prostate tissues were classified considering the grade levels and were divided into the control, BPH, and grade 1–5 groups. mRNA expression levels of genes were determined by qPCR. In addition, TRPM2 was evaluated immunohistochemically for each group. In PC-3 cell line, TRPM2 was silenced through siRNA transfection, and autophagy induction was analyzed by acridine orange (AO) staining. Results The qPCR and immunoreactivity results showed that the increased TRPM2 expression levels in human PCa samples were paralleled with higher grade levels. The autophagic–apoptotic gene expressions showed high variability in different grade levels. Also, silencing TRPM2 in PC-3 cells altered autophagic gene expressions and caused autophagy induction according to the AO staining results. Conclusion We showed that the autophagy–TRPM2 association may take place in the molecular basis of PCa and accordingly this connection may be targeted as a new therapeutic approach in PCa.

Impact of EGFR mutation on the clinical efficacy of PD-1 inhibitors in patients with pulmonary adenocarcinoma Abstract Purpose We evaluated the predictive role of EGFR mutation on the efficacy of PD-1/PD-L1 inhibitor therapy in patients with advanced pulmonary adenocarcinoma while considering clinical factors such as PD-L1 expression, gender, and smoking status. Methods Patients were required to have available data for EGFR mutation, PD-L1 expression, and efficacy of PD-1/PD-L1 inhibitors. Results Among 178 patients with EGFR-mutant (n = 38) or wild-type (WT) (n = 140) tumors, the EGFR mutation group had a lower objective response rate (ORR) (15.8% vs. 32.9%, p = 0.04) than the EGFR WT group, similar to the pattern observed for other factors: weak/negative PD-L1 expression vs. strong PD-L1 expression (17.3% vs. 39.2%, p = 0.001); never smokers vs. smokers (19.4% vs. 35.1%, p = 0.03); and females vs. males (21.0% vs. 33.6%, p = 0.08). EGFR mutation and weak/negative PD-L1 expression were associated with a significantly shorter median PFS than EGFR WT (1.9 vs. 3.0 months, p = 0.04) and strong PD-L1 expression (1.6 vs. 3.9 months, p = 0.007), respectively. In multivariate analysis, EGFR mutation predicted worse ORR [hazard ratio (HR) 3.15; 95% confidence interval (CI) 1.15–8.63] and PFS (HR 1.75, 95% CI 1.11–2.75), as did weak/negative PD-L1 expression (ORR, HR 3.46, 95% CI 1.62–7.37; and PFS, HR 1.72, 95% CI 1.17–2.53). Conclusions Together with PD-L1 expression, EGFR mutation status is an important factor to predict the efficacy of PD-1/PD-L1 inhibitors in patients with pulmonary adenocarcinoma.

CD110 promotes pancreatic cancer progression and its expression is correlated with poor prognosis Abstract Purpose This study aimed at investigating the function and significance of CD110 expression in pancreatic cancer. Methods We performed immunohistochemical staining for CD110 expression in tumor samples from 86 patients with pancreatic cancer. We evaluated clinical outcomes and other clinicopathological factors to determine the significance of CD110 on survival and liver metastasis. We examine thrombopoietin–CD110 signaling in cancer cell extravasation in vitro and in vivo. We investigated the effects of CD110 knockdown on liver metastasis in a splenic xenograft mouse model. Results CD110 expression in cancer cells was associated with low-histological-grade invasive ductal carcinoma, and patients with high CD110 expression had poorer prognosis (P = 0.0003). High CD110 expression was an independent predictor of liver metastasis (P = 0.0422). Knockdown of CD110 expression significantly attenuated cell migration and invasion. Treatment with thrombopoietin promoted pancreatic cancer cell extravasation. In the presence of thrombopoietin, CD110 increased cell viability through the activation of the ERK–MYC signaling pathway. Knockdown of CD110 expression inhibited liver metastases in the mouse model. Conclusions CD110 promotes pancreatic cancer progression and it may serve as a predictive factor for liver metastasis.

CD24 targeting bi-specific antibody that simultaneously stimulates NKG2D enhances the efficacy of cancer immunotherapy Abstract Purpose Bi-specific antibody (BsAb) is an emerging novel format of antibody. We aimed to develop the natural killer (NK) cell receptor NK group 2, member D (NKG2D)-mediated, immune surveillance system. In this system, the NKG2D ligand MHC class I-related chain A (MICA) was fused with BsAb, which targeted a cluster of differentiation 24 (CD24), a tumor-initiating cell marker that is over-expressed on hepatocellular carcinoma (HCC). Methods The Homo MICA extracellular domains (hMICA) were fused to the end of the heavy chain of cG7 with the flexible pentapeptide (Gly-Gly-Gly-Gly-Ser; G4S), which formed the cG7-MICA that was further identified using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) and western blotting (WB). The targeting specificity was characterized using the Surface Plasmon Resonance (SPR) technology and a flow cytometry assay. Furthermore, the design of BsAb cG7-MICA that targeted CD24 and NKG2D was proven to enhance antibody-dependent, cell-mediated cytotoxicity (ADCC) in vitro by the CytoTox 96 Nonradioactive Cytotoxicity assay. Degranulation and a cytokine production assay of NK cells demonstrated that NK cells were activated effectively by cG7-MICA. Further, in HCC-bearing nude mice, the anti-tumor effects of cG7-MICA combined with sorafenib were verified again. Results We purified cG7-MICA successfully, and it has a high affinity. In vivo, cG7-MICA recruited NK cells to the tumor site and improved the anti-tumor efficacy of sorafenib. cG7-MICA also activated NK cells to release interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α), and it increased the CD107a expression on the surface of the NK cells in vitro. Conclusion NK cells play a major role in the natural, innate immune system, and they have the function of identifying and killing target cells. cG7-MICA remodels the function of MICA molecules to activate NK cells, which provides a possible strategy for HCC-targeting immunotherapy.

Autoantibody against 14-3-3 zeta: a serological marker in detection of gastric cancer Abstract Purpose Autoantibody to 14-3-3 zeta was identified in gastric cancer (GC) by serological proteome analysis (SERPA) in our previous study. We comprehensively evaluated its ability to detect GC, determined its association with clinical characteristics, and explored its temporal change in GC patients before and after gastrectomy resection in this study. Methods Anti-14-3-3 zeta antibody was examined by immunoassay in sera from 465 GC patients and 465 normal individuals, and also in 69 serial sera from 26 GC patients before and after resection. Results The frequency of anti-14-3-3 zeta were significantly higher in GC group than in control group, with AUC of 0.627. The appearance of anti-14-3-3 zeta showed no difference in different tumor stage, tumor size, tumor differentiation, and lymphatic metastasis, but was higher in GC patients with family tumor history than without family tumor history. When anti-14-3-3 zeta was combined with clinical markers (CEA, CA199 and CA724), the sensitivity increased to 52.7%. In the follow-up analysis, the titer of anti-14-3-3 zeta was higher in post-resection sera than pre-resection sera, and no difference was observed in CEA, CA199 and CA724. Anti-14-3-3 zeta showed an increase from negative status to positive status in six patients after resection, while other three clinical markers presented different change in GC patients after resection. Conclusions Autoantibody against 14-3-3 zeta could be a potential diagnostic biomarker and improve the sensitivity of CEA, CA199 and CA724 in diagnosis of GC. Further largescale studies will be needed to validate its performance in GC patients after resection.

Estrogen receptor beta increases sensitivity to enzalutamide in androgen receptor-positive triple-negative breast cancer Abstract Purpose Androgen receptor (AR) is playing an important role in the progression of a subset of TNBC. We evaluated the impact of ERβ expression along with anti-AR drugs in AR-positive TNBC. Methods ERβ expression was examined in AR-positive TNBC cell line using MTT assay, scratch and Annexin V-FITC assay in the presence or absence of anti-androgens. Protein levels of involved molecules were assessed using Western blot. Receptors' localization was detected by immunofluorescence and their physical association was examined using proximity ligation assay (PLA), which enables the visualization of interacting proteins in fixed cells and tissues. Results Transient transfection of ERβ in MDA-MB 453 AR-positive TNBC cell line significantly inhibited cell proliferation, metastatic potential and induced apoptosis. ERβ expression reversed the aggravating role of AR in both indirect and direct ways. Indirectly, ERβ decreased AR activation through the inhibition of PI3K/AKT signaling pathway. Directly, ERβ formed heterodimers with AR in MDA-MB 453 cells and in human tissue samples impeding AR from forming homodimers. Enzalutamide is a more potent anti-androgen in AR + TNBC compared to bicalutamide. ERβ expression increased the sensitivity of MDA-MB 453 cells to anti-androgens and especially to enzalutamide. The administration of enzalutamide enhanced AR:ERβ heterodimers formation increasing the anti-tumor capacity of ERβ. Conclusions Collectively, our results provide evidence for a novel mechanism by which ERβ exerts oncosuppressive effect in AR-positive TBNC through direct and indirect interactions with AR. Moreover, ERβ expression may identify a new subset of TNBC that would respond more favorable to anti-androgens.

Risk group-adapted adjuvant radiotherapy for WHO grade I and II skull base meningioma Abstract Purpose Salvage treatment including surgery and radiotherapy (RT) for recurrent or progressive meningioma is not an easy task, especially for the skull base location. And yet, criteria for adjuvant radiotherapy after initial surgery are not clearly defined for WHO grade I/II meningioma. We determined prognostic factors for recurrence and evaluated the benefit of risk group-adapted adjuvant RT for WHO grade I/II meningioma in the skull base. Methods We reviewed 272 patients who underwent surgery and were pathologically confirmed with WHO grade I or II skull base meningioma between January 2000 and July 2017. Subgroup analyses were performed for WHO grade I (259 patients) and WHO grade II (13 patients) meningiomas to evaluate the benefit of RT in each subgroup. Results Patients with WHO grade II meningiomas tended to present more neurologic symptoms and to receive RT more frequently. In prognostic factor analysis, tumor size (p = 0.039), surgical extent (p < 0.001), and RT (p = 0.005) were associated with recurrence-free survival (RFS). In subgroup analysis of WHO grade I, RFS was significantly better in RT group after matching other variables. The risk stratification was performed using three risk factors (petroclival location, tumor size, Simpson grade) in WHO grade I patients, and significantly different RFS was observed according to the risk group in non-RT patients. Conclusions Tumor size, Simpson grade, and adjuvant RT were prognostic factors. The risk group-adapted approach can facilitate the selection of patients who may benefit from adjuvant RT for WHO grade I/II skull base meningiomas.

Clinical impact of circulating LAPTM4B-35 in pancreatic ductal adenocarcinoma Abstract Purpose LAPTM4B is upregulated in a wide range of cancers associated with poor prognosis. However, the clinical impact of LAPTM4B as diagnostic and prognostic marker in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Thus, the aim of the present study was to investigate the expression of LAPTM4B as circulating marker in PDAC. Methods Expression analysis of LAPTM4B-35 in pancreatic tissue and preoperative blood serum samples of 169 patients with PDAC UICC Stages I–IV (n = 98), chronic pancreatitis (n = 41), and healthy controls (n = 30) by immunohistochemistry, Western blot, and ELISA. Descriptive and explorative statistical analyses of LAPTM4B-35's potential as diagnostic and prognostic marker in PDAC. Results Expression of LAPTM4B-35 was significantly increased in tumor tissue and corresponding blood serum samples of patients with PDAC (each p < 0.001) and it could well discriminate PDAC from healthy controls and chronic pancreatitis (p < 0.001; p = 0.0037). LAPTM4B-35 in combination with CA.19-9 outperforms the diagnostic accuracy with an AUC of 0.903 (p < 0.001), sensitivity of 82%, and specificity of 92%. Kaplan–Meier survival analysis revealed an improved overall survival in PDAC UICC I–IV with low expression of circulating LAPTM4B-35 (17 versus 10 months, p = 0.039) as well as an improved relapse-free survival in curatively treated PDAC UICC I–III (16 versus 10 months; p = 0.037). Multivariate overall and recurrence-free survival analyses identified LAPTM4B-35 as favorable prognostic factor in PDAC patients (HR 2.73, p = 0.021; HR 3.29, p = 0.003). Conclusion LAPTM4B-35 is significantly deregulated in PDAC with high diagnostic and prognostic impact as circulating tumor marker.

Meeting report of the 14th Japan–Korea joint symposium on cancer and aging research: current status of translational research and approaches to precision medicine Abstract Purpose The 14th Japan–Korea joint symposium on cancer and aging research was held at an auditorium of Saga University, Japan, May 31–Jun 2, 2018. Participants presented 31 oral and 21 poster presentations, two lectures at a luncheon seminar, plus special lectures from two Korean Emeritus Professors and founders of our joint symposia. The essential parts of the lectures are reviewed here. Results This Symposium was called Japan–Korea, because the host country comes first. Our symposia are organized every 18 months and the program includes keynote and plenary lectures, and oral and poster presentations. (1) Subjects related to cancer development at this symposium were: prostate cancer progression, molecules activating GSK3β, suppressing the activation of cancer stem cells, profiling human B cell receptor repertoires, and hereditary gastrointestinal cancer syndrome. (2) Subjects related to treatment were: G-quadruplex ligands for glioma stem cells, tankyrase inhibitor for colorectal cancer, and eradication of ATL. (3) Cancer prevention subjects were: physical adsorption of EGCG to cell membrane, inhibition of immune evasion of cancer cells with EGCG, and prevention with antidiabetic agents. (4) Aging subjects were life span extension with Toll-like receptor 5 vaccine and reversal of senescence with inhibitors of ATM and ROCK. (5) The results of epidemiology focused on aldehyde dehyrogenase-2 and alcohol consumption. Conclusion The 14th symposium demonstrated the cutting-edge of presentations with discussion of numerous ideas by the participants.

Iron oxide–gold core–shell nano-theranostic for magnetically targeted photothermal therapy under magnetic resonance imaging guidance Abstract Recent efforts in the area of photothermal therapy (PTT) follow two important aims: (i) selective targeting of plasmonic nanoparticles to the tumor and (ii) real-time guidance of PTT operation through employing multimodal imaging modalities. In the present study, we utilized a multifunctional theranostic nanoplatform constructed from iron (III) oxide–gold (Fe2O3@Au) core–shell nanoparticles to fulfill these aims. The Au shell exhibits surface plasmon resonance, a property that is exploited to realize PTT. The magnetic core enables Fe2O3@Au to be employed as a magnetic resonance imaging (MRI) contrast agent. Furthermore, the magnetic core has the potential to establish a magnetic drug targeting strategy through which Fe2O3@Au can be directed to the tumor site by means of magnetic field. To test these potentials, Balb/c mice bearing CT26 colorectal tumor model were intravenously injected with Fe2O3@Au. Immediately after injection, a magnet was placed on the tumor site for 3 h to concentrate nanoparticles, followed by the near infrared (NIR) laser irradiation. MRI study confirmed the accumulation of nanoparticles within the tumor due to T2 enhancement capability of Fe2O3@Au. The in vivo thermometry results demonstrated that the tumors in magnetic targeting group had a significantly higher temperature elevation rate upon NIR irradiation than non-targeted group (~ 12 °C vs. 8.5 °C). The in vivo antitumor assessment revealed that systemic injection of Fe2O3@Au in combination with magnetic targeting and NIR irradiation resulted in complete remission of tumor growth. Therefore, Fe2O3@Au can establish a targeted PTT strategy for efficient eradication of tumor cells under the guidance of MRI.