Katrin Schierle

In-depth characterization has introduced new molecular subtypes of gastric cancer (GC). To identify these, new approaches and techniques are required. Liquid biopsies are trendsetting and provide an easy and feasible method to identify and to monitor GC patients. In a prospective cohort of 87 GC patients, extracellular vesicles (EVs) were isolated from 250 µL of plasma. The total RNA was isolated with TRIZOL. The total RNA amount and the relative mRNA levels of CD44, PTEN, and FASN were measured by qRT-PCR. The isolation of EVs and their contained mRNA was possible in all 87 samples investigated. The relative mRNA levels of PTEN were higher in patients already treated by chemotherapy than in chemo-naïve patients. In patients who had undergone neoadjuvant chemotherapy followed by gastrectomy, a decrease in the total RNA amount was observed after neoadjuvant chemotherapy and gastrectomy, while FASN and CD44 mRNA levels decreased only after gastrectomy. The amount of RNA and the relative mRNA levels of FASN and CD44 in EVs were affected more significantly by chemotherapy and gastrectomy than by chemotherapy alone. Therefore, they are a potential biomarker for monitoring treatment response. Future analyses are needed to identify GC-specific key RNAs in EVs, which could be used for the diagnosis of gastric cancer patients in order to determine their molecular subtype and to accompany the therapeutic response.

Currently, colorectal cancer (CRC) is mainly identified via a visual assessment during colonoscopy, increasingly used artificial intelligence algorithms, or surgery. Subsequently, CRC is confirmed through a histopathological examination by a pathologist. Hyperspectral imaging (HSI), a non-invasive optical imaging technology, has shown promising results in the medical field. In the current study, we combined HSI with several artificial intelligence algorithms to discriminate CRC. Between July 2019 and May 2020, 54 consecutive patients undergoing colorectal resections for CRC were included. The tumor was imaged from the mucosal side with a hyperspectral camera. The image annotations were classified into three groups (cancer, CA; adenomatous margin around the central tumor, AD; and healthy mucosa, HM). Classification and visualization were performed based on a four-layer perceptron neural network. Based on a neural network, the classification of CA or AD resulted in a sensitivity of 86% and a specificity of 95%, by means of leave-one-patient-out cross-validation. Additionally, significant differences in terms of perfusion parameters (e.g., oxygen saturation) related to tumor staging and neoadjuvant therapy were observed. Hyperspectral imaging combined with automatic classification can be used to differentiate between CRC and healthy mucosa. Additionally, the biological changes induced by chemotherapy to the tissue are detectable with HSI.

In the original article, the title of the article is “Restoration of MARCK enhances chemosensitivity in cancer”. The authors would like to chan

Purpose: Increased ATP-binding-cassette (ABC) transporter activity is a major cause of chemotherapy resistance in cancer. The ABC transporter family member ABCB1 is often overexpressed in colorectal cancer (CRC). Phosphatidylinositol-4,5-bisphosphat (PI(4,5)P₂)-dependent pathways are involved in the regulation of ABCB1 function. The protein Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS) is a pivotal regulator of PI(4,5)P₂ and inactivated in many CRC cancers via genetic deletion or hyperphosphorylation. Therefore, MARCKS may critically impact ABCB1. Methods: CRC samples as well as CRC cell lines were tested for a connection between MARCKS and ABCB1 via immunofluorescence and Western-blot analysis. ABCB1 function was studied via calcein influx assay under treatment with known ABCB1 inhibitors (verapamil, tariquidar) as well as the kinase inhibitor bosutinib. ABCB1 internalization and MARCKS translocation was analyzed via confocal microscopy exploiting the endocytosis inhibitors chlorpromazine and dynasore. Abundance of PI(4,5)P₂ was monitored by intramolecular fluorescence resonance energy transfer (FRET). Reproductive cell survival was studied via colorimetric WST-1 and clonogenic assays in combination with exposure to the chemotherapeutics doxorubicin and 5-fuorouracil (5-FU). Results: We found increased ABCB1 expression in MARCKS negative CRC patient tumor samples and established CRC cell lines. Mechanistically, the reconstitution of MARCKS function via recombinant expression or the pharmacological inhibition of MARCKS phosphorylation led to a substantial decrease in ABCB1 activity. In CRC cells, bosutinib treatment resulted in a MARCKS translocation from the cytosol to the plasma membrane, while simultaneously, ABCB1 was relocated to intracellular compartments. Inhibition of MARCKS phosphorylation via bosutinib rendered cells more sensitive to the chemotherapeutics doxorubicin and 5-FU. Conclusions: Cells devoid of MARCKS function showed incomplete ABCB1 internalization, leading to higher ABCB1 activity enhancing chemoresistance. Vice versa our data suggest the prevention of MARCKS inhibition by reversing hyperphosphorylation or genomic restoration after deletion as two promising approaches to overcome tumor cell resistance towards chemotherapeutic ABCB1 substrates.

Zusammenfassung Das Ideal eines Instituts für Pathologie bestand aus dem großen Sektionsbereich und einer breiten Präparatesammlung für die Ausbildung von Studenten und klinisch tätigen Ärzten. Zusätzliche Abteilungen, die den Sektionsbereich unterstützten, waren ein chemisches und bakteriologisches Labor. In weiteren Abteilungen waren experimentelle Labors für Biologie, Immunologie, Zellforschung und Tierställe angesiedelt. Ein Hauptpfeiler des Medizinstudiums stellte die Pathologie für das Verständnis des Krankheitsbegriffs und der Krankheitsentstehung dar. In diesem Zusammenhang wurde meist der Endzustand einer Erkrankung im Rahmen einer Sektion erfasst. Der Sonderverdienst Virchows war die zusätzliche Betrachtung der zellulären Ebene unter Hinzuziehung mikroskopischer Präparate. Im Gegensatz dazu wurden in Großbritannien und USA in den Instituten neben den Sektionen klinisch relevante Arbeiten durchgeführt. Die Analyse von Zeitschriftartikeln aus den Jahren 1920 bis 1940 von zwei deutschsprachigen Zeitschriften, Virchows Archiv und Naunyn-Schmiedebergs Archiv für experimentelle Pathologie und Pharmakologie (heute: Naunyn-Schmiedeberg’s Archives of Pharmacology), sowie zwei englischsprachigen Zeitschriften, Journal of Pathology and Bacteriology sowie American Journal of Pathology, zeigte stark schwankende Veröffentlichungszahlen. Anhand von Publikationen konnte nachvollzogen werden, dass in deutschen Zeitschriften der Pathologie überwiegend Erkrankungen großer Bandbreite beschrieben und auch häufig erstbeschrieben wurden. In der britischen Zeitschrift für Pathologie wurden vor allem infektiologische Themen sowie zahlreiche Tierexperimente veröffentlicht. In der amerikanischen Zeitschrift war ein sehr breites Spektrum – von klinisch relevanten Tätigkeitsfeldern des Pathologen einschließlich klinischer Chemie bis tierexperimentellen Arbeiten – abgebildet, unter anderem viele Ausführungen zu histologischen Techniken.

Question: Tumor angiogenesis is modulated on epigenetic and protein levels with potential implications on immune cell responses. However, the importance of related angiogenic biomarkers in cholangiocarcinoma (CCA) is unknown. We tested human samples of CCA for expression of microRNA involved in angiogenesis, angiopoietins (Angs) and monocyte subsets expressing Ang-receptor TIE2 (TEMs) with regard to their prognostic significance after liver resection. Methods: Expression of miR-107, miR-126, miR-128 and miR-145 was analyzed in frozen samples of intrahepatic cholangiocarcinoma (iCC; n = 43) and hilar cholangiocarcinoma (HC; n = 45), whereas Ang-1 and Ang-2 patterns, as well as TEMs, were detected in paraffin-embedded iCC (n = 88) sections. MiRNA expression and abundance of TEMs and Angs were correlated with clinicopathologic characteristics and survival. Results: MiR-126 was downregulated in ˜70% of all CCA samples with high relative expression being associated with smaller tumors in HC and less lymph node metastasis in iCC. High Ang-1 expression was associated with less lymphangiosis carcinomatosa and better histological grading (all ρ< 0.05). Absence of TEMs in iCC correlated with elevated CA19 – 9 levels. High relative miR-126 and low miR-128 were associated with decreased survival in iCC and HC, respectively (all p < 0.05). High miR-126 and low miR-128 and TEMs were confirmed as independent prognostic factors for recurrence-free and overall survival (all p < 0.05). Conclusions: Our results suggest angiogenic miRNA, Ang-1 expression profiles and TEMs responses of prognostic value in human CCA. Besides possible functional links between angiogenic miRNA expression profiles, Angs and immune cell responses by TEM, our data have clinical implications as novel diagnostic tools.