Transcriptional regulation of metastatic [Id]entity by KLF17

A new player identified in the regulation of epithelial-to-mesenchyme transition, cell invasiveness and metastasis

Detektory MOSFET jako narzędzie do weryfikowania dawek promieniowania X w radioterapii

SummaryPurposeApplication of MOSFET detectors in photon beam dose measurements in vivo in radiotherapy.Materials and methodsBefore measuring doses in vivo the following parameters such as: the dosimeter response to dose absorption, temperature, gantry angles and field side changes were determined using 6MV and 15MV photon beams. All measurements were made in a phantom to investigate the MOSFET accuracy, in electron equilibrium with a 0.6 cm3 Farmer ionization chamber.ResultsMOSFET parameters are presented in graphs. The conformity between the planned dose and the dose measured in vivo within ±5% was observed in 86% of patients treated with 6MV photon beams and 91% patients treated with 15MV, respectively (SD=3.5%).ConclusionsMOSFET detectors are a useful tool for verifying the planned dose in external photon radiotherapy

MOSFET detectors as a tool for the verification of therapeutic doses of electron beams in radiotherapy

AimTo examine the characteristics of MOSFET (Metal – Oxide Semiconductor Field Effect Transistor) detectors for the purpose of electron beam dose determination in in vivo radiotherapy.Materials/MethodsIndications of MOSFET detectors were recorded from phantom measurements, including: dose values of electron beams, the environmental temperature of the detectors, the incidence direction of an electron beam on the detector, the size of the irradiated field.The change in sensitivity of the detectors when under the effects of accumulated doses was also tested.Because of the very small dimensions of the detectors, they were placed in specially designed aluminium capsules – to ensure electron equilibrium (δ electrons) during the dose measurement. The detector indications were compared to those seen in a Markus type ionization chamber with a calibration certificate. The measurements were made for electron beams with energies of 6, 9, 12, 15, 18 and 21 MeV.ResultsThe following were established experimentally: There is a linear relationship between detector indications and the dose value. A drop in detector sensitivity is associated with increased environmental temperature (as much as 6% as temperatures rise from 22°C to 42°C). There is a non-linear drop in detector sensitivity with accumulated dose. Detector indications are not affected by changes in incident beam angles within the range of –70° to +70°. The dependency of detector indications on the size of the irradiated field conform with those recorded in the ionization chamber, with variations of up to 1.5%. The dependencies and correction coefficients determined in this study allow measurement of electron beam doses with an accuracy of 2.2%.ConclusionsMOSFET detectors are a useful tool for verification of the entrance doses in electron beam radiotherapy

The technique of total body irradiation applied at the leszczyński memorial hospital

PurposeTo improve the reproducibility of patient positioning in fractionated irradiation and to achieve uniform irradiation of the patient, within 12–15Gy, excluding the lungs.MethodTwo special body frames were manufactured, one for treatment planning and the other for the treatment itself. Special tin markers were inserted in the walls to make it possible for a patient to maintain the same position during each fraction of irradiation. Patient treatment was carried out in six fractions (four lateral and two AP/PA fields), twice a day, over three consecutive days. The lungs were shielded during AP/PA fractions and during one lateral fraction. The shape of the shields for AP/PA fields was determined with the use of computer tomography scans, and for lateral fields on the basis of radiographic pictures taken by a simulator. The doses calculated at some selected anatomical points for every patient were checked by in vivo measurements which were carried out by means of MOSFET detectors.Results and conclusionsReproducibility of patient positioning during consecutive treatments and a uniform total dose distribution over the range of 12 – 15 Gy (except in the lungs) have been achieved. This has been confirmed by in vivo measurements

Expression and display of UreA of Helicobacter acinonychis on the surface of Bacillus subtilis spores

<p>Abstract</p> <p>Background</p> <p>The bacterial endospore (spore) has recently been proposed as a new surface display system. Antigens and enzymes have been successfully exposed on the surface layers of the <it>Bacillus subtilis </it>spore, but only in a few cases the efficiency of expression and the effective surface display and have been determined. We used this heterologous expression system to produce the A subunit of the urease of the animal pathogen <it>Helicobater acinonychis</it>. Ureases are multi-subunit enzymes with a central role in the virulence of various bacterial pathogens and necessary for colonization of the gastric mucosa by the human pathogen <it>H. pylori</it>. The urease subunit UreA has been recognized as a major antigen, able to induce high levels of protection against challenge infections.</p> <p>Results</p> <p>We expressed UreA from <it>H. acinonychis </it>on the <it>B. subtilis </it>spore coat by using three different spore coat proteins as carriers and compared the efficiency of surface expression and surface display obtained with the three carriers. A combination of western-, dot-blot and immunofluorescence microscopy allowed us to conclude that, when fused to CotB, UreA is displayed on the spore surface (ca. 1 × 10³recombinant molecules per spore), whereas when fused to CotC, although most efficiently expressed (7-15 × 10³recombinant molecules per spore) and located in the coat layer, it is not displayed on the surface. Experiments with CotG gave results similar to those with CotC, but the CotG-UreA recombinant protein appeared to be partially processed.</p> <p>Conclusion</p> <p>UreA was efficiently expressed on the spore coat of <it>B. subtilis </it>when fused to CotB, CotC or CotG. Of these three coat proteins CotC allows the highest efficiency of expression, whereas CotB is the most appropriate for the display of heterologous proteins on the spore surface.</p

MOSFET detectors as a tool for dose verification in photon beam radiotherapy

CelZastosowanie detektorów typu MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) do pomiaru dawki in vivo w radioterapii.Metody i materiałyWykonano pomiary polegające na zbadaniu zależności wskazań detektorów MOSFET od podanej dawki promieniowania, temperatury ich otoczenia, kierunku padania wiązki promieniowania na detektor oraz od wielkości napromienianego pola – dla wiązek fotonów 6MV i 16 MV. Pomiary zależności wskazań detektorów zostały wykonane w fantomie oraz w powietrzu, w warunkach równowagi elektronowej. W tym celu, ze względu na bardzo małe wymiary detektorów, zaprojektowano nakładki z aluminium, które zapewniały warunki równowagi elektronowej podczas pomiaru dawki. Detektory zostały wykalibrowane z pomocą komory jonizacyjnej typu Farmer 0,6 cm3.WynikiWyniki badań wymienionych wyżej zależności przedstawiono na wykresach. Wykonane, wykalibrowanymi detektorami, pomiary in vivo dawki wejściowej (na głębokości maksymalnej dawki) wykazały zgodność między zaplanowaną i zmierzoną dawką – w granicach tolerancji ±5% – u 86% pacjentów poddanych radioterapii z użyciem wiązki fotonów 6MV i u 91% pacjentów z użyciem wiązki fotonów 15MV (SD=3.5%).WniosekDetektory MOSFET stanowią dobre narzędzie pomiarowe w radioterapii do weryfikowania zaplanowanej dawki promieniowania X wytwarzanego w liniowych przyspieszaczach.PurposeApplication of MOSFET detectors in photon beam dose measurements in vivo in radiotherapy.Materials and methodsBefore measuring doses in vivo the following parameters such as: the dosimeter response to dose absorption, temperature, gantry angles and field side changes were determined using 6MV and 15MV photon beams. All measurements were made in a phantom to investigate the MOSFET accuracy, in electron equilibrium with a 0.6 cm3 Farmer ionization chamber.ResultsMOSFET parameters are presented in graphs. The conformity between the planned dose and the dose measured in vivo within ±5% was observed in 86% of patients treated with 6MV photon beams and 91% patients treated with 15MV, respectively (SD=3.5%).ConclusionsMOSFET detectors are a useful tool for verifying the planned dose in external photon radiotherapy

Deubiquitinase UCHL1 Maintains Protein Homeostasis through the PSMA7–APEH–Proteasome Axis in High-grade Serous Ovarian Carcinoma

High-grade serous ovarian cancer (HGSOC) is characterized by chromosomal instability, DNA damage, oxidative stress, and high metabolic demand that exacerbate misfolded, unfolded, and damaged protein burden resulting in increased proteotoxicity. However, the underlying mechanisms that maintain protein homeostasis to promote HGSOC growth remain poorly understood. This study reports that the neuronal deubiquitinating enzyme, ubiquitin carboxyl-terminal hydrolase L1 (UCHL1), is overexpressed in HGSOC and maintains protein homeostasis. UCHL1 expression was markedly increased in HGSOC patient tumors and serous tubal intraepithelial carcinoma (HGSOC precursor lesions). High UCHL1 levels correlated with higher tumor grade and poor patient survival. UCHL1 inhibition reduced HGSOC cell proliferation and invasion, as well as significantly decreased the in vivo metastatic growth of ovarian cancer xenografts. Transcriptional profiling of UCHL1-silenced HGSOC cells revealed downregulation of genes implicated with proteasome activity along with upregulation of endoplasmic reticulum stress–induced genes. Reduced expression of proteasome subunit alpha 7 (PSMA7) and acylaminoacyl peptide hydrolase (APEH), upon silencing of UCHL1, resulted in a significant decrease in proteasome activity, impaired protein degradation, and abrogated HGSOC growth. Furthermore, the accumulation of polyubiquitinated proteins in the UCHL1-silenced cells led to attenuation of mTORC1 activity and protein synthesis, and induction of terminal unfolded protein response. Collectively, these results indicate that UCHL1 promotes HGSOC growth by mediating protein homeostasis through the PSMA7–APEH–proteasome axis.This study identifies the novel links in the proteostasis network to target protein homeostasis in HGSOC and recognizes the potential of inhibiting UCHL1 and APEH to sensitize cancer cells to proteotoxic stress in solid tumors

Gene Expression Signature of Normal Cell-of-Origin Predicts Ovarian Tumor Outcomes

The potential role of the cell-of-origin in determining the tumor phenotype has been raised, but not adequately examined. We hypothesized that distinct cells-of-origin may play a role in determining ovarian tumor phenotype and outcome. Here we describe a new cell culture medium for in vitro culture of paired normal human ovarian (OV) and fallopian tube (FT) epithelial cells from donors without cancer. While these cells have been cultured individually for short periods of time, to our knowledge this is the first long-term culture of both cell types from the same donors. Through analysis of the gene expression profiles of the cultured OV/FT cells we identified a normal cell-of-origin gene signature that classified primary ovarian cancers into OV-like and FT-like subgroups; this classification correlated with significant differences in clinical outcomes. The identification of a prognostically significant gene expression signature derived solely from normal untransformed cells is consistent with the hypothesis that the normal cell-of-origin may be a source of ovarian tumor heterogeneity and the associated differences in tumor outcome

Starved epithelial cells uptake extracellular matrix for survival

Extracellular matrix adhesion is required for normal epithelial cell survival, nutrient uptake and metabolism. This requirement can be overcome by oncogene activation. Interestingly, inhibition of PI3K/mTOR leads to apoptosis of matrix-detached, but not matrix-attached cancer cells, suggesting that matrix-attached cells use alternate mechanisms to maintain nutrient supplies. Here we demonstrate that under conditions of dietary restriction or growth factor starvation, where PI3K/mTOR signalling is decreased, matrix-attached human mammary epithelial cells upregulate and internalize β4-integrin along with its matrix substrate, laminin. Endocytosed laminin localizes to lysosomes, results in increased intracellular levels of essential amino acids and enhanced mTORC1 signalling, preventing cell death. Moreover, we show that starved human fibroblasts secrete matrix proteins that maintain the growth of starved mammary epithelial cells contingent upon epithelial cell β4-integrin expression. Our study identifies a crosstalk between stromal fibroblasts and epithelial cells under starvation that could be exploited therapeutically to target tumours resistant to PI3K/mTOR inhibition

Modeling of Intracellular Taurine Levels Associated with Ovarian Cancer Reveals Activation of p53, ERK, mTOR and DNA-Damage-Sensing-Dependent Cell Protection

Taurine, a non-proteogenic amino acid and commonly used nutritional supplement, can protect various tissues from degeneration associated with the action of the DNA-damaging chemotherapeutic agent cisplatin. Whether and how taurine protects human ovarian cancer (OC) cells from DNA damage caused by cisplatin is not well understood. We found that OC ascites-derived cells contained significantly more intracellular taurine than cell culture-modeled OC. In culture, elevation of intracellular taurine concentration to OC ascites-cell-associated levels suppressed proliferation of various OC cell lines and patient-derived organoids, reduced glycolysis, and induced cell protection from cisplatin. Taurine cell protection was associated with decreased DNA damage in response to cisplatin. A combination of RNA sequencing, reverse-phase protein arrays, live-cell microscopy, flow cytometry, and biochemical validation experiments provided evidence for taurine-mediated induction of mutant or wild-type p53 binding to DNA, activation of p53 effectors involved in negative regulation of the cell cycle (p21), and glycolysis (TIGAR). Paradoxically, taurine’s suppression of cell proliferation was associated with activation of pro-mitogenic signal transduction including ERK, mTOR, and increased mRNA expression of major DNA damage-sensing molecules such as DNAPK, ATM and ATR. While inhibition of ERK or p53 did not interfere with taurine’s ability to protect cells from cisplatin, suppression of mTOR with Torin2, a clinically relevant inhibitor that also targets DNAPK and ATM/ATR, broke taurine’s cell protection. Our studies implicate that elevation of intracellular taurine could suppress cell growth and metabolism, and activate cell protective mechanisms involving mTOR and DNA damage-sensing signal transduction