Discovery of Pancreatic Ductal Adenocarcinoma-Related Aberrant Glycosylations: A Multilateral Approach of Lectin Microarray-Based Tissue Glycomic Profiling With Public Transcriptomic Datasets

Aberrant protein glycosylation is one of the most notable features in cancerous tissues, and thereby glycoproteins with disease-relevant glycosylation alterations are fascinating targets for the development of biomarkers and therapeutic agents. For this purpose, a reliable strategy is needed for the analysis of glycosylation alterations occurring on specific glycoproteins during the progression of cancer. Here, we propose a bilateral approach combining lectin microarray-based tissue glycomic profiling and database-derived transcriptomic datasets. First, lectin microarray was used to perform differential glycomic profiling of crude extracts derived from non-tumor and tumor regions of frozen tissue sections from pancreatic ductal adenocarcinoma (PDAC). This analysis revealed two notable tissue glycome alterations in PDAC samples: increases in sialylated glycans and bisecting N-acetylglucosamine and a decrease in ABO blood group antigens. To examine aberrations in the glycosylation machinery related to these glycomic alterations, we next employed public datasets of gene expression profiles in cancerous and normal pancreases provided by The Cancer Genome Atlas and the Genotype-Tissue Expression projects, respectively. In this analysis, glycosyltransferases responsible for the glycosylation alterations showed aberrant gene expression in the cancerous tissues, consistent with the tissue glycomic profiles. The correlated alterations in glycosyltransferase expression and tissue glycomics were then evaluated by differential glycan profiling of a membrane N-glycoprotein, basigin, expressed in tumor and non-tumor pancreatic cells. The focused differential glycomic profiling for endogenous basigin derived from non-tumor and cancerous regions of PDAC tissue sections demonstrated that PDAC-relevant glycan alterations of basigin closely reflected the notable features in the disease-specific alterations in the tissue glycomes. In conclusion, the present multi-omics strategy using public transcriptomic datasets and experimental glycomic profiling using a tiny amount of clinical specimens successfully demonstrated that basigin is a representative N-glycoprotein that reflects PDAC-related aberrant glycosylations. This study indicates the usefulness of large public data sets such as the gene expression profiles of glycosylation-related genes for evaluation of the highly sensitive tissue glycomic profiling results. This strategy is expected to be useful for the discovery of novel glyco-biomarkers and glyco-therapeutic targets.

Collective and contractile filament motions in the myosin motility assay

Cells require mechanical forces for their physiological functions. The forces are generated mainly from molecular interactions between actin filaments, cross-linking proteins, and myosin motors in the actin cytoskeleton. To better understand the molecular interactions, many studies employed myosin motility assays with actin filaments propelled by myosin heads fixed on a surface. Various interesting behaviors of actin filaments have been observed in the motility assay experiments. Despite the popularity of the motility assays, there were only a few computational models designed for simulating the motility assay systems. Most of the previous models have limitations which precluded full understanding of molecular origins for behaviors of actin filaments. In this study, we used an agent-based computational model based on Brownian dynamics for simulating the motility assay system. Our model rigorously describes the mechanics, dynamics, and interactions of actin filaments, cross-linking proteins, and molecular motors. Using the model, we first investigated how properties of actin filaments and motors affect gliding motions of actin filaments without volume-exclusion effects as a base study. We found that actin filaments can continuously glide at relative fast speed only when they are sufficiently longer than the average spacing between neighboring motors and that the gliding speed of F-actins shows a biphasic dependence on processivity of motors. Then, we showed that volume-exclusion effects between actin filaments can induce diverse collective movements and alignment of actin filaments, thus creating thick bundles and ring-like structures in the absence of cross-linking proteins. Lastly, we demonstrated that cross-linking proteins can lead to distinct contractile behaviors of actin networks depending on the density and kinetics of the cross-linking proteins. Results from our study show the ability of our model to simulate the motility assay system under various conditions and provide insights into understanding of different behaviors of actin filaments.

The Chaperone FACT and Histone H2B Ubiquitination Maintain S. pombe Genome Architecture through Genic and Subtelomeric Functions

The histone chaperone FACT and histone H2B ubiquitination (H2Bub) facilitate RNA polymerase II (Pol II) passage through chromatin, yet it is not clear how they cooperate mechanistically. We used genomics, genetic, biochemical, and microscopic approaches to dissect their interplay in Schizosaccharomyces pombe. We show that FACT and H2Bub globally repress antisense transcripts near the 5' end of genes and inside gene bodies, respectively. The accumulation of these transcripts is accompanied by changes at genic nucleosomes and Pol II redistribution. H2Bub is required for FACT activity in genic regions. In the H2Bub mutant, FACT binding to chromatin is altered and its association with histones is stabilized, which leads to the reduction of genic nucleosomes. Interestingly, FACT depletion globally restores nucleosomes in the H2Bub mutant. Moreover, in the absence of Pob3, the FACT Spt16 subunit controls the 3' end of genes. Furthermore, FACT maintains nucleosomes in subtelomeric regions, which is crucial for their compaction.

Syndapin constricts microvillar necks to form a united rhabdomere in Drosophila photoreceptors

Drosophila photoreceptors develop from polarized epithelial cells that have apical and basolateral membranes. During morphogenesis, the apical membranes subdivide into a united bundle of photosensory microvilli (rhabdomeres) and a surrounding supporting membrane (stalk). By EMS-induced mutagenesis screening, we found that the F-Bin/Amphiphysin/Rvs (F-BAR) protein syndapin is essential for apical membrane segregation. The analysis of the super-resolution microscopy, STORM and the electron microscopy suggest that syndapin localizes to the neck of the microvilli at the base of the rhabdomere. Syndapin and moesin are required to constrict the neck of the microvilli to organize the membrane architecture at the base of the rhabdomere, to exclude the stalk membrane. Simultaneous loss of syndapin along with the microvilli adhesion molecule chaoptin significantly enhanced the disruption of stalk-rhabdomere segregation. However, loss of the factors involving endocytosis do not interfere. These results indicated syndapin is most likely functioning through its membrane curvature properties, and not through endocytic processes for stalk-rhabdomere segregation. Elucidation of the mechanism of this unconventional domain formation will provide novel insights into the field of cell biology.

Mobility of Molecular Motors Regulates Contractile Behaviors of Actin Networks

Cells generate mechanical forces primarily from interactions between F-actin, cross-linking proteins, myosin motors, and other actin-binding proteins in the cytoskeleton. To understand how molecular interactions between the cytoskeletal elements generate forces, a number of in vitro experiments have been performed but are limited in their ability to accurately reproduce the diversity of motor mobility. In myosin motility assays, myosin heads are fixed on a surface and glide F-actin. By contrast, in reconstituted gels, the motion of both myosin and F-actin is unrestricted. Because only these two extreme conditions have been used, the importance of mobility of motors for network behaviors has remained unclear. In this study, to illuminate the impacts of motor mobility on the contractile behaviors of the actin cytoskeleton, we employed an agent-based computational model based on Brownian dynamics. We find that if motors can bind to only one F-actin like myosin I, networks are most contractile at intermediate mobility. In this case, less motor mobility helps motors stably pull F-actins to generate tensile forces, whereas higher motor mobility allows F-actins to aggregate into larger clustering structures. The optimal intermediate motor mobility depends on the stall force and affinity of motors that are regulated by mechanochemical rates. In addition, we find that the role of motor mobility can vary drastically if motors can bind to a pair of F-actins. A network can exhibit large contraction with high motor mobility because motors bound to antiparallel pairs of F-actins can exert similar forces regardless of their mobility. Results from this study imply that the mobility of molecular motors may critically regulate contractile behaviors of actin networks in cells.

Abstract P4-16-13: Prospective study of scalp cooling for hair loss prevention in Japanese breast cancer women receiving (neo)adjuvant chemotherapy

Introduction

Recently scalp cooling during chemotherapy infusion has been reported to be quite effective to mitigate chemotherapy-induced alopecia. But data in Asian patients are quite limited.

Patients and methods

Japanese breast cancer female patients who planned to receive (neo)adjuvant chemotherapy were offered to participate in this prospective study of scalp cooling with Paxman Scalp Cooling System for alopecia prevention. The scalp cooling was done 30 minutes prior to and during and 90 minutes after each chemotherapy infusion. Photographs of the head of the participants were taken from 5 directions, namely front, back, both sides, and top, on the day of chemotherapy infusion and 1 month after the last infusion. Two investigators consisting of a physician and a nurse judged the grade of alopecia by looking at the photographs according to the WHO classification. The primary outcomes were the rates of patients with Grade 3 alopecia (defined as hair loss of > 50%) and the rates of patients who used a wig or hat to conceal the hair loss one month after the last infusion of chemotherapy. This paper reports on the former outcome mainly. They were asked to answer a brief questionnaire regarding headache, fatigue, chill etc. shortly after each cooling. They could use the cooling cap for free on the first cycle of chemotherapy. But they were required to purchase it (about 1,130 US$) for the scalp cooling of the following cycles.

Results

One hundred forty three patients participated in the study and actually used the cooling cap at least once. The mean and median age of them are 50.6 and 50, respectively (28 - 76). One hundred twenty nine patients completed the planned chemotherapy of 4 to 8 cycles (89 Pts 4 cycles, 1 Pt 6 cycles, 39 Pts 8 cycles). Among them (7 patients were not evaluable), 74 patients (60.7 %) had Grade 3 alopecia 1 month after chemotherapy. In 80 patients who used the scalp cooling system throughout the planned chemotherapy (1 patient was not evaluable), 36 patients (45.6 %) experienced Grade 3 alopecia. On the other hand, among 49 patients who discontinued the cooling mostly after the 1st cycle (6 were not evaluable), 38 (88.3 %) had Grade 3 alopecia. When we restrict them to 33 (5 were not evaluable) who decided to discontinue the cooling by day10 of the first cycle of chemotherapy to exclude the patients who discontinued it because of less effect on alopecia prevention than they expected, 25 (89.3 %) experienced Grade 3 alopecia. Comparing the results of those who completed the cooling and patients who decided to discontinue it by day10 of the first cycle, the rates of Grade 3 alopecia (45.6 % vs. 89.3 %) were statistically significantly different in favor of the former (P = 0.0001). Most patients complained of some headache, chill, and pain of the jaw.

Conclusion

Scalp cooling with Paxman Scalp Cooling System during chemotherapy infusion in Asian women seems as effective for hair loss mitigation as in Caucasian women.

Citation Format: Ohsumi S, Kiyoto S, Takahashi M, Hara F, Takashima S, Aogi K, Matsuda M, Yamamura N, Matsuda A, Yamauchi T, Doi M. Prospective study of scalp cooling for hair loss prevention in Japanese breast cancer women receiving (neo)adjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-16-13.

Transition of Spleen Volume Long After Pediatric Living Donor Liver Transplantation for Biliary Atresia

PURPOSE

After undergoing the Kasai procedure for biliary atresia (BA), most patients develop severe splenomegaly that tends to be improved by liver transplantation. However, fluctuations in splenic volume long after transplantation remain to be elucidated.

PATIENTS AND METHODS

Seventy-one consecutive patients who had undergone pediatric living donor liver transplantation (LDLT) for BA were followed up in our outpatient clinic for 5 years. They were classified into 3 groups according to their clinical outcomes: a good course group (GC, n = 41) who were maintained on only 1 or without an immunosuppressant, a liver dysfunction group (LD, n = 18) who were maintained on 2 or 3 types of immunosuppressants, and a vascular complication group (VC, n = 11). Splenic and hepatic volumes were calculated by computed tomography in 464 examinations and the values compared before and after the treatment, especially in the VC group.

RESULTS

Splenic volume decreased exponentially in the GC group, with splenic volume to standard spleen volume ratio (SD) being 1.59 (0.33) 5 years after liver transplantation. Splenic volume to standard spleen volume ratios were greater in the VC and LD groups than in the GC group. Patients in the VC group with portal vein stenosis developed liver atrophy and splenomegaly, whereas those with hepatic vein stenosis developed hepatomegaly and splenomegaly. Interventional radiation therapy tended to improve the associated symptoms.

CONCLUSIONS

Fluctuations in splenic volume long after pediatric LDLT for BA may reflect various clinical conditions. Evaluation of both splenic and hepatic volumes can facilitate understanding clinical conditions following pediatric LDLT.

Novel chemical compound SINCRO with dual function in STING-type I interferon and tumor cell death pathways

Recent years have seen a number of regulatory approvals for immune oncology or immunotherapies based on their ability to enhance antitumor immune responses. Nevertheless, the majority of patients remain refractory to these treatments; hence, new therapies that augment current immunotherapies are required. Innate immune receptors that recognize nucleic acids are potent activators of subsequent T-cell responses and, as a result, can evoke potent antitumor immune responses. Herein, we present a novel compound N-{3-[(1,4'-bipiperidin)-1'-yl]propyl}-6-[4-(4-methylpiperazin-1-yl)phenyl]picolinamide (SINCRO; STING-mediated interferon-inducing and cytotoxic reagent, original) as an anticancer drug that activates the cytosolic DNA-sensing STING (stimulator of interferon genes) signaling pathway leading to the induction of type I interferon (IFN) genes. Indeed, IFN-β gene induction by SINCRO is abolished in STING-deficient cells. In addition to its IFN-inducing activity, SINCRO shows STING-independent cytotoxic activity against cancer cells. SINCRO does not evoke DNA double-strand break or caspase-3 cleavage. Thus, SINCRO induces cell death in a method different from conventional apoptosis-inducing pathways. Finally, we provide evidence that giving SINCRO significantly attenuates in vivo tumor growth by both type I IFN-dependent and independent mechanisms. Thus, SINCRO is an attractive anticancer compound with dual function in that it evokes type I IFN response to promote antitumor immunity as well as inducing tumor cell death. SINCRO may provide a new platform for the development of drugs for effective cancer therapy.

Development of a Highly Sensitive Device for Counting the Number of Disease-Specific Exosomes in Human Sera

BACKGROUND

Although circulating exosomes in blood play crucial roles in cancer development and progression, difficulties in quantifying exosomes hamper their application for reliable clinical testing. By combining the properties of nanobeads with optical disc technology, we have developed a novel device named the ExoCounter to determine the exact number of exosomes in the sera of patients with various types of cancer.

METHOD

In this system, individual exosomes were captured in the groove of an optical disc coated with antibodies against exosome surface antigens. The captured exosomes were labeled with antibody-conjugated magnetic nanobeads, and the number of the labeled exosomes was counted with an optical disc drive.

RESULTS

We showed that the ExoCounter could detect specific exosomes derived from cells or human serum without any enrichment procedures. The detection sensitivity and linearity with this system were higher than those with conventional detection methods such as ELISA or flow cytometry. In addition to the ubiquitous exosome markers CD9 and CD63, the cancer-related antigens CD147, carcinoembryonic antigen, and human epidermal growth factor receptor 2 (HER2) were also used to quantify cancer cell line-derived exosomes. Furthermore, analyses of a cross-sectional cohort of sera samples revealed that HER2-positive exosomes were significantly increased in patients with breast cancer or ovarian cancer compared with healthy individuals and those with noncancer diseases.

CONCLUSIONS

The ExoCounter system exhibits high performance in the direct detection of exosomes in cell culture and human sera. This method may enable reliable analysis of liquid biopsies.

Combined spectroscopic and TDDFT study of single-double anthocyanins for application in dye-sensitized solar cells

This research investigates single-double anthocyanins experimentally and theoretically for the first time.

Charge behavior in a plasmonic photocatalyst composed of Au and TiO2

Redox reaction sites on a Au nanoparticle-deposited TiO₂ (Au/TiO₂) plasmonic photocatalyst are visualized using a chemical microanalytical technique for investigating charge behaviors in Au/TiO₂.