Takeshi Yoshikawa

The Expression Profile of Phosphatidylinositol in High Spatial Resolution Imaging Mass Spectrometry as a Potential Biomarker for Prostate Cancer

High-resolution matrix-assisted laser desorption/ionization imaging mass spectrometry (HR-MALDI-IMS) is an emerging application for the comprehensive and detailed analysis of the spatial distribution of ionized molecules in situ on tissue slides. HR-MALDI-IMS in negative mode in a mass range of m/z 500–1000 was performed on optimal cutting temperature (OCT) compound-embedded human prostate tissue samples obtained from patients with prostate cancer at the time of radical prostatectomy. HR-MALDI-IMS analysis of the 14 samples in the discovery set identified 26 molecules as highly expressed in the prostate. Tandem mass spectrometry (MS/MS) showed that these molecules included 14 phosphatidylinositols (PIs), 3 phosphatidylethanolamines (PEs) and 3 phosphatidic acids (PAs). Among the PIs, the expression of PI(18:0/18:1), PI(18:0/20:3) and PI(18:0/20:2) were significantly higher in cancer tissue than in benign epithelium. A biomarker algorithm for prostate cancer was formulated by analyzing the expression profiles of PIs in cancer tissue and benign epithelium of the discovery set using orthogonal partial least squares discriminant analysis (OPLS-DA). The sensitivity and specificity of this algorithm for prostate cancer diagnosis in the 24 validation set samples were 87.5 and 91.7%, respectively. In conclusion, HR-MALDI-IMS identified several PIs as being more highly expressed in prostate cancer than benign prostate epithelium. These differences in PI expression profiles may serve as a novel diagnostic tool for prostate cancer.

Decreased expression of lysophosphatidylcholine (16:0/OH) in high resolution imaging mass spectrometry independently predicts biochemical recurrence after surgical treatment for prostate cancer.

Human prostate cancers are highly heterogeneous, indicating a need for various novel biomarkers to predict their prognosis. Lipid metabolism affects numerous cellular processes, including cell growth, proliferation, differentiation, and motility. Direct profiling of lipids in tissue using high‐resolution matrix‐assisted laser desorption/ionization imaging mass spectrometry (HR‐MALDI‐IMS) may provide molecular details that supplement tissue morphology.

An EP4 Antagonist ONO-AE3-208 Suppresses Cell Invasion, Migration, and Metastasis of Prostate Cancer

EP4 is one of the prostaglandin E2 receptors, which is the most common prostanoid and is associated with inflammatory disease and cancer. We previously reported that over-expression of EP4 was one of the mechanisms responsible for progression to castration-resistant prostate cancer, and an EP4 antagonist ONO-AE3-208 in vivo suppressed the castration-resistant progression regulating the activation of androgen receptor. The aim of this study was to analyze the association of EP4 with prostate cancer metastasis and the efficacy of ONO-AE3-208 for suppressing the metastasis. The expression levels of EP4 mRNA were evaluated in prostate cancer cell lines, LNCaP, and PC3. EP4 over-expressing LNCaP was established, and their cell invasiveness was compared with the control LNCaP (LNCaP/mock). The in vitro cell proliferation, invasion, and migration of these cells were examined under different concentrations of ONO-AE3-208. An in vivo bone metastatic mouse model was constructed by inoculating luciferase expressing PC3 cells into left ventricle of nude mice. Their bone metastasis was observed by bioluminescent imaging with or without ONO-AE3-208 administration. The EP4 mRNA expression levels were higher in PC3 than in LNCaP, and EP4 over-expression of LNCaP cells enhanced their cell invasiveness. The in vitro cell invasion and migration were suppressed by ONO-AE3-208 in a dose-dependent manner without affecting cell proliferation. The in vivo bone metastasis of PC3 was also suppressed by ONO-AE3-208 treatment. EP4 expression levels were correlated with prostate cancer cell invasiveness and EP4 specific antagonist ONO-AE3-208 suppressed cell invasion, migration, and bone metastasis, indicating that it is a potential novel therapeutic modality for the treatment of metastatic prostate cancer.

An original patient-derived xenograft of prostate cancer with cyst formation.

The high rate of failure of new agents in oncology clinical trials indicates a weak understanding of the complexity of human cancer. Recent understanding of the mechanisms underlying castration resistance in prostate cancer led to the development of new agents targeting the androgen receptor pathway; however, their effectiveness is limited. Hence, there is a need for experimental systems that are able to better reproduce the biological diversity of prostate cancer in preclinical settings. In this study, we established a unique patient‐derived xenograft (PDX) model to identify biomarkers for treatment efficacy and resistance and better understand prostate cancer biology.

Image Overlay Support with 3DCG Organ Model for Robot-Assisted Laparoscopic Partial Nephrectomy

We have developed a surgery support system for robot-assisted laparoscopic partial nephrectomy. In our system, a 3D computer graphics (3DCG) model, which includes a kidney, arteries, veins, and tumors, is saved separately and overlaid on the surgeon’s viewing endoscopic camera image through the operator’s console monitor in real time. The position and orientation of the 3DCG model is calculated from the optical flow of the endoscopic camera images, and the model is moved semi-automatically. The display condition of each part of the 3DCG model is independently controlled anytime by using a mouse, rotary controllers, or key board.

Abstract 2813: EP4 antagonist suppresses bone metastasis in prostate cancer.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Introduction Bone metastasis is one of the most common complications in clinical intractable castration-resistant prostate cancer (CRPC) and advanced prostate cancer period. The invasion ability of cancer cells was thought to have important relationship with the potential of cancer metastasis. EP4 receptor is overexpressed in several cancers, and enhanced EP4 receptor signaling has been previously shown to correlate with the invasion of several different cancer types. In present study, we found that EP4 antagonist can in vitro suppress the invasion phenotype abilities of CRPC PC3 cells, LNCaP cells with EP4 overexpressed which have the tendency to castration-resistance and in vivo suppress the CRPC bone metastasis animal models. Materials and methods Materials In vitro: PC3 cell and LNCaP cell in vivo: PC3/Luc cell. EP4-specific antagonist: ONO-AE3-208 Methods RNA interference was used to stably transfected EP4 to LNCaP with the pcDNA3.1-EP4, so as to be the LNCaP with vector control (LNCaP-mock) and LNCaP with EP4 overexpressed (LNCaP/EP4+) as described in our previous article. Effect on cell proliferation was determined firstly by the MTT assay. Transwell invasion assay was used to in vitro examine the metastasis abilities of PC3 cells, LNCaP cells, LNCaP/EP4+ and all after EP4 antagonist affected. Cells with ONO-AE3-208 at the final concentration of 0.1μmol/L, 1μmol/L and 10μmol/L were administrated to be the experimental group. To observe the effect of EP4 antagonist on the bone metastasis of prostate cancer in vivo, PC3/Luc cells were inoculated into the left cardiac ventricle of 5-week-old male nude mice. The mice developed osteolytic lesions with a mean endpoint at 52±7 days.To assess whether EP4 antagonist suppresses bone metastasis, ONO-AE3-208 (10 mg/kg/d) was given to the animals 5 days a week I.p. which the same volume of DDW was given as the control.To detect PC3 cell dissemination, bioluminescent imaging (BLI) was applied using a cooled CCD camera. We evaluated the efficacy of ONO-AE3-208 by measuring the photon counts of the metastatic lesions in the mandible and both hip joints in a blinded manner. Results The invasion assay showed that ONO-AE3-208 can inhibit the invasive abilities of both PC3 and LNCaP/EP4+ in a dose-dependent manner (p < 0.01). In animal experiment, metastatic bone lesions in the control group progressed while the photon emission was significantly suppressed in the ONO-AE3-208 treatment group during the observation period from day 28 every 7 days (p < 0.01). Conclusion We demonstrated that EP4 antagonist can in vitro inhibit the invasive abilities of CRPC PC3 and LNCaP/EP4+ cells. The administration of it can also suppress the bone metastasis of CRPC in vivo. Citation Format: Song Xu, Takayuki Goto, Takeshi Yoshikawa, Zhengyu Zhang, Liming Wang, Naoki Terada, Osamu Ogawa. EP4 antagonist suppresses bone metastasis in prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2813. doi:10.1158/1538-7445.AM2013-2813