Optimum Design of Quenching Capacitor Integrated Silicon Photomultipliers for TOF-PET Application

AbstractThe prototype SiPM was designed and fabricated for MRI compatible PET using the customized CMOS process at National Nanofab Center in KAIST. The SiPM was designed to have a size of 3x3 mm2 composed of micro-cells of 65x65μm2 with a fill factor of 68%. The size of a micro-cell was determined by optimization between the photon detection efficiency (PDE) and the dynamic range for the photons of 511 keV from LYSO crystal. In the micro-cell structure, a specially designed quenching capacitor (QC) is added parallel to quenching resistor using the Metal-Insulator-Metal (MIM) process. This QC integrated SiPMs (QC-SiPM) was devised to realize rapid response of output pulses and to enhance the timing resolution of SiPM. Coincidence timing resolution of PET detectors depends on the output pulse shapes which are the convolution of the intrinsic pulse shape of scintillation crystals and the single photon pulse shape at the micro-cell in a SiPM. A quenching capacitor parallel to a quenching resistor provides a fast current path at the beginning stage of avalanche process, than reduces rising time of single photon pulse shape. In this study the rise time of the QC-SiPM signal was analyzed to be 22.5ns while that for the regular SiPM was 34.3ns

Overexpression of the miR-141/200c cluster promotes the migratory and invasive ability of triple-negative breast cancer cells through the activation of the FAK and PI3K/AKT signaling pathways by secreting VEGF-A

Migration in miR-141/200c-transduced HCC-38 and Hs578T cells treated with an anti-VEGF-A-neutralizing antibody. (A, D) Migration in miR-141/200c-transduced HCC-38 and Hs578T cells. Images of the crystal violet-stained cells that migrated horizontally in the trans-well migration assay (upper). The absorbance values of extracted crystal violet in migrated cells (lower). The migratory abilities of the miR-200c cells (~1.6-fold and ~1.7-fold, HCC-38 and Hs578T, respectively) were significantly increased compared with those of the control cells. (B, E) Measurement of the secreted levels of cytokines and growth factors (IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, GM-CSF, IFN-γ, TNF-α, and VEGF-A). Transduction of miR-141/200c into HCC-38 and Hs578T cells promoted significantly higher VEGF-A secretion than that of control cells. (C, F) Trans-well migration of anti-VEGF-A-neutralizing antibody-treated cells. The enhanced migration of the miR-141/200c-transduced HCC-38 cells were significantly suppressed by treatment with anti-VEGF-A-neutralizing antibodies, but miR-141/200c-transduced Hs578T cells still showed increased migratory ability compared with control cells. *p < 0.05, **p < 0.001. (JPG 188 kb

IL-6-mediated cross-talk between human preadipocytes and ductal carcinoma in situ in breast cancer progression

Background The function of preadipocytes in the progression of early stage breast cancer has not been fully elucidated at the molecular level. To delineate the role of preadipocytes in breast cancer progression, we investigated the cross-talk between human breast ductal carcinoma in situ (DCIS) cells and preadipocytes with both an in vitro culture and xenograft tumor model. Methods GFP or RFP was transduced into human DCIS cell line MCF10DCIS.com cells or preadipocytes using lentivirus. Cell sorter was used to separate pure, viable populations of GFP- or RFP-transduced cells. Cell viability and proliferation was assessed by crystal violet assays and cell migration and invasion capability was assayed by the transwell strategy. Gene and protein levels were measured by western blot, RT-PCR and immunostaining. Adipokines and cytokines were quantified using ELISA. Human tumor xenografts in a nude mice model were used. Ultrasound imaging of tumors was performed to evaluate the therapeutic potential of a IL-6 neutralizing antibody. Results In the co-culture system with the MCF10DCIS.com and preadipocytes, MCF10DCIS.com proliferation, migration and invasion were enhanced by preadipocytes. Preadipocytes exhibited in an increased IL-6 secretion and cancer-associated fibroblast markers expression, FSP1 and α-SMC in co-culture with MCF10DCIS.com or in MCF10DCIS.com conditioned media, whereas the adipocyte differentiation capacity was suppressed by co-culture with MCF10DCIS.com. A neutralizing antibody of IL-6 or IL-6R suppressed the promotion of MCF10DCIS.com proliferation and migration by co-culture with preadipocytes. In the xenograft tumor model, the tumor growth of MCF10DCIS.com was enhanced by the co-injection of preadipocytes, and the administration of IL-6 neutralizing antibodies resulted in potent effects on tumor inhibition. Conclusions Our findings suggest that IL-6-mediated cross-talk between preadipocytes and breast DCIS cells can promote the progression of early stage breast cancer. Therefore, blocking IL-6 signaling might be a potential therapeutic strategy for breast DCIS characterized by pathological IL-6 overproduction.This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and future Planning (2015R1A2A1A05001860) and by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2015R1D1A1A01059376). Sul Ki Choi, Hyelim Kim and Yin Ji Piao are the awardees of graduate student fellowship funded by Brain Korea 21 Plus (BK21 Plus)

Different Biological Action of Oleic Acid in ALDHhigh and ALDHlow Subpopulations Separated from Ductal Carcinoma In Situ of Breast Cancer.

The mechanisms underlying breast cancer progression of ductal carcinoma in situ (DCIS) associated with fatty acids are largely unknown. In the present study, we compared the action of oleic acid (OA) on two human DCIS cell lines, MCF10DCIS.COM (ER/PR/HER2-negative) and SUM225 (HER2 overexpressed). OA led to a significant increase in proliferation, migration, lipid accumulation and the expression of lipogenic proteins, such as SREBP-1, FAS and ACC-1, in MCF10DCIS.COM cells but not SUM225 cells. The ALDHhigh subpopulation analyzed by the ALDEFLUOR assay was approximately 39.2±5.3% of MCF10DCIS.COM cells but was small (3.11±0.9%) in SUM225 cells. We further investigated the different biological action of OA in the distinct ALDHlow and ALDHhigh subpopulations of MCF10DCIS.COM cells. OA led to an increase in the expression of ALDH1A1, ALDH1A2 and ALDH1A3 in MCF10DCIS.COM cells. SREBP-1 and ACC-1 were highly expressed in ALDHhigh cells relative to ALDHlow cells, whereas FAS was higher in ALDHlow cells. In the presence of OA, ALDHhigh cells were more likely to proliferate and migrate and displayed significantly high levels of SREBP-1 and FAS and strong phosphorylation of FAK and AKT relative to ALDHlow cells. This study suggests that OA could be a critical risk factor to promote the proliferation and migration of ALDHhigh cells in DCIS, leading to breast cancer progression

Different Biological Action of Oleic Acid in ALDH^high and ALDH^low Subpopulations Separated from Ductal Carcinoma <i>In Situ</i> of Breast Cancer

<div><p>The mechanisms underlying breast cancer progression of ductal carcinoma in situ <b>(</b>DCIS) associated with fatty acids are largely unknown. In the present study, we compared the action of oleic acid (OA) on two human DCIS cell lines, MCF10DCIS.COM (ER/PR/HER2-negative) and SUM225 (HER2 overexpressed). OA led to a significant increase in proliferation, migration, lipid accumulation and the expression of lipogenic proteins, such as SREBP-1, FAS and ACC-1, in MCF10DCIS.COM cells but not SUM225 cells. The ALDH^high subpopulation analyzed by the ALDEFLUOR assay was approximately 39.2±5.3% of MCF10DCIS.COM cells but was small (3.11±0.9%) in SUM225 cells. We further investigated the different biological action of OA in the distinct ALDH^low and ALDH^high subpopulations of MCF10DCIS.COM cells. OA led to an increase in the expression of ALDH1A1, ALDH1A2 and ALDH1A3 in MCF10DCIS.COM cells. SREBP-1 and ACC-1 were highly expressed in ALDH^high cells relative to ALDH^low cells, whereas FAS was higher in ALDH^low cells. In the presence of OA, ALDH^high cells were more likely to proliferate and migrate and displayed significantly high levels of SREBP-1 and FAS and strong phosphorylation of FAK and AKT relative to ALDH^low cells. This study suggests that OA could be a critical risk factor to promote the proliferation and migration of ALDH^high cells in DCIS, leading to breast cancer progression.</p></div

Oleic acid (OA) promotes the proliferation and migration ability of MCF10DCIS.COM cells but not SUM225 cells, whereas palmitic acid (PA) leads to cell death in both cells.

<p>(A and B) MTT assay of cell proliferation in MCF10DCIS.COM and SUM225 cells incubated with increasing OA or PA. OA induced significantly increased viability in MCF10DCIS.COM cells but led to cell death in SUM225 cells. PA induced the death of both MCF10DCIS.COM and SUM225 cells. (C) Trans-well assay of cell migration in MCF10DCIS.COM and SUM 225 cells. OA significantly promoted the migration of MCF10DCIS.COM cell but not SUM225 cells. (D) Wound healing assay of lateral migration of MCF10DCIS.COM cells incubated with OA. OA significantly enhanced the lateral migration of MCF10DCIS.COM cells. All the experiments were performed at least in triplicate and the values are reported as the means ± standard error. *<i>p</i><0.05, **<i>p</i><0.01.</p

Oleic acid (OA) further promotes the proliferation and migration abilities and upregulates lipogenic proteins in ALDH^high cells.

<p>(A) Quantitative real-time RT-PCR of ALDH1A1, ALDH1A2 and ALDH1A3 in MCF10DCIS.COM cells. All subtypes of ALDH1 were significantly increased by OA. Notably, OA led to a remarkable increase in ALDH1A2 in MCF10DCIS.COM cells. (B) MTT assay of cell proliferation in ALDH^high and ALDH^low cells incubated with OA. OA-induced proliferation of ALDH^high cells was greater than that of ALDH^low cells. (C) Trans-well assay of cell migration in ALDH^high and ALDH^low cells. The OA-induced migration ability was higher in ALDH^high cells than ALDH^low cells. (D) Representative Western blot of SREBP-1, FAS and ACC-1 in ALDH^high cells and ALDH^low cells. (E, F and G) Analysis of expression levels of SREBP-1, FAS and ACC-1. Significantly higher expression of SERBP-1 and ACC-1 was observed in ALDH^high cells, whereas FAS was significantly higher in ALDH^low cells. OA led to the significant upregulation of SREBP-1 and FAS in ALDH^high cells and the significant upregulation of SREBP-1 and downregulation of FAS in ALDH^low cells. All experiments were performed at least in triplicate, and the values are reported as the means ± standard error. *<i>p</i><0.05, **<i>p</i><0.01.</p

Oleic acid (OA) induces lipid accumulation and the upregulation of lipogenic proteins in MCF10DCIS.COM cells but not SUM225 cells.

<p>(A) Representative Oil Red O staining in MCF10DCIS.COM and SUM 225 cells incubated with OA. A large number of lipid droplets were observed in MCF10DCIS.COM cells but not SUM225 cells. (B) Quantitative analysis of intracellular lipid contents from Oil Red O staining. OA led to lipid accumulation in MCF10DCIS.COM cells. (C) Representative Western blot of SREBP-1, FAS and ACC-1 in MCF10DCIS.COM and SUM 225 cells incubated with OA. (D) Quantitative analysis of lipogenic protein levels in MCF10DCIS.COM and SUM225 cells. A significantly higher level of SERBP-1 was observed in MCF10DCIS.COM cells relative to SUM225 cells. The FAS level was significantly higher in SUM225 cells than MCF10DCIS.COM cells. The level of ACC-1 was similar between MCF10DCIS.COM cells and SUM225 cells (upper). OA resulted in the significant upregulation of SREBP-1, FAS and ACC-1 in MCF10DCIS.COM cells (middle) but led to the downregulation of SREBP-1 and the upregulation of ACC-1 significantly in SUM225 cells (lower). All experiments were performed at least in triplicate, and the values are reported as the means ± standard error. *<i>p</i><0.05, **<i>p</i><0.01.</p

Distinct subpopulations of ALDH1^high and ALDH1^low cells were separated from MCF10DCIS.COM cells.

<p>(A) Representative flow cytometry for ALDEFLUOR assay showing the percentage of ALDH^high cells in MCD10DCIS.COM and SUM225 cells. Graph showed that the ALDH^high cell population obtained from experiments performed at least in triplicate. Cells exhibiting high ALDH activity were higher in MCF10DCIS.COM cells relative to SUM225 cells. (B) Quantitative real-time RT-PCR of ALDH1A1, ALDH1A2 and ALDH1A3 in ALDH1^high and ALDH1^low subpopulation cells separated from MCF10DCIS.COM cells. Significantly higher expression levels of ALDH1A2 and ALDH1A3 mRNAs were detected in ALDH^high cells relative to ALDH^low cells. The experiments were performed at least in triplicate, and the values are reported as the means ± standard error. *<i>p</i><0.05, **<i>p</i><0.01. (C) RT-PCR analysis of CD24 and CD44 mRNAs in ALDH^high and ALDH^low cells. CD44 mRNA was higher in ALDH1^high cells than ALDH1^low cells. (D) Flow cytometric analysis of CD44 and CD24. Of MCF10DCIS.COM cells, 70% exhibited the CD44+/CD24- phenotype. CD44+/CD24- cell populations were higher in separated ALDH1^high cells than ALDH1^low cells. (E) Immunofluorescence staining of CD44, CD24 and ALDH1. ALDH1^high cells expressed a high level of ALDH1 and CD44, whereas ALDH1^low cells displayed a high level of CD24 and a low level of ALDH1 and CD44.</p