Complex Formation of Sulfobetaine Surfactant and Ionic Polymers and Their Stimuli Responsivity.

We investigated the kinds of complexes sulfobetaine surfactant and ionic polymer formed using lauramidopropyl hydroxysultane (LAPHS) as a sulfobetaine surfactant, poly(sodium styrenesulfonate) (PSSNa) as the anionic polymer and poly[3-(methacrylamido)propyl trimethylammonium chloride] (PMAPTAC) as the cationic polymer. The fundamental properties of LAPHS at various salt concentrations were estimated by various measurements, and it was confirmed that the LAPHS micelles alone did not show temperature responsiveness. The presence of large aggregates in addition to LAPHS micelles was confirmed in the aggregates prepared by adding PSSNa to LAPHS at a charge ratio of 1:0.5, 1:1, and 1:2. However, the aggregates could not be formed when the salt concentration was high or when a monomer was added instead of the polymer. This revealed that the cation part of sulfobetaine, which is the shell of LAPHS micelles, and the anion part of PSSNa electrostatically interacted with each other to form a large aggregate. On the other hand, unlike the case of LAPHS micelles alone and the aggregate consisting of LAPHS micelles and PSSNa, the aggregate of LAPHS micelles and PMAPTAC showed an unprecedented phenomenon of "clear → opaque → clear" with increasing concentration in the concentration range above CMC. The change in the transition temperature due to the change of concentration was a factor. Additionally, we confirmed that the transition temperature was lowered when the concentration was higher than CMC or the salt concentration was increased, and the transition temperature was increased when the PMAPTAC with a high degree of polymerization was added. These results suggested that the LAPHS micelles and the ionic polymer form an aggregate, and the temperature responsivity can be expressed by the interaction with the cationic polymer.

The Evolutionary Origins of Recurrent Pancreatic Cancer.

Surgery is the only curative option for stage I/II pancreatic cancer; nonetheless, most patients will experience a recurrence after surgery and die of their disease. To identify novel opportunities for management of recurrent pancreatic cancer, we performed whole-exome or targeted sequencing of 10 resected primary cancers and matched intrapancreatic recurrences or distant metastases. We identified that recurrent disease after adjuvant or first-line platinum therapy corresponds to an increased mutational burden. Recurrent disease is enriched for genetic alterations predicted to activate MAPK/ERK and PI3K-AKT signaling and develops from a monophyletic or polyphyletic origin. Treatment-induced genetic bottlenecks lead to a modified genetic landscape and subclonal heterogeneity for driver gene alterations in part due to intermetastatic seeding. In 1 patient what was believed to be recurrent disease was an independent (second) primary tumor. These findings suggest routine post-treatment sampling may have value in the management of recurrent pancreatic cancer. SIGNIFICANCE: The biological features or clinical vulnerabilities of recurrent pancreatic cancer after pancreaticoduodenectomy are unknown. Using whole-exome sequencing we find that recurrent disease has a distinct genomic landscape, intermetastatic genetic heterogeneity, diverse clonal origins, and higher mutational burden than found for treatment-naïve disease.See related commentary by Bednar and Pasca di Magliano, p. 762.This article is highlighted in the In This Issue feature, p. 747.

A unifying paradigm for transcriptional heterogeneity and squamous features in pancreatic ductal adenocarcinoma.

Pancreatic cancer expression profiles largely reflect a classical or basal-like phenotype. The extent to which these profiles vary within a patient is unknown. We integrated evolutionary analysis and expression profiling in multiregion-sampled metastatic pancreatic cancers, finding that squamous features are the histologic correlate of an RNA-seq-defined basal-like subtype. In patients with coexisting basal and squamous and classical and glandular morphology, phylogenetic studies revealed that squamous morphology represented a subclonal population in an otherwise classical and glandular tumor. Cancers with squamous features were significantly more likely to have clonal mutations in chromatin modifiers, intercellular heterogeneity for MYC amplification and entosis. These data provide a unifying paradigm for integrating basal-type expression profiles, squamous histology and somatic mutations in chromatin modifier genes in the context of clonal evolution of pancreatic cancer.

Preoperative periodontal treatment and its effects on postoperative infection in cardiac valve surgery.

Objectives: Oral infection control is important for patients undergoing cardiac valve replacement (CVR) as prophylaxis for postoperative complications. This study examined the changes in oral health status by preoperative periodontal treatment and its effects on postsurgical complications in CVR patients. Material and methods: We recruited 64 patients undergoing CVR who received preoperative periodontal treatment at our hospital as the intervention group and retrospectively reviewed the medical records of 38 patients who had undergone CVR surgery without dental intervention as the control group. Oral health status was assessed at the first visit to our dental office, 1 day before surgery, and >7 days after surgery. Days of high fever, antibiotics use, and postoperative hospitalization were recorded for the intervention and control groups for statistical comparisons. Results: In the intervention group, oral health status significantly improved from the initial visit to >7 days after surgery. There were significantly fewer days of high fever (>37.5°C) in the intervention group than in the control group, with comparable results for other events. Conclusions: This study's findings suggest that preoperative periodontal treatment can improve oral health status surrounding CVR surgery and could be the contributor of the reduction in the risk of postoperative infection.

Perioperative changes in oral bacteria number in patients undergoing cardiac valve surgery.

Perioperative oral care can reduce the risk of postoperative infections. This study examined 1) changes in oral bacteria counts during the perioperative period and 2) differences in bacteria counts in patients with or without endotracheal intubation. 47 patients who visited our hospital dental clinic prior to cardiac valve surgery were prospectively recruited. The number of bacteria on the tongue, tooth surface, and buccal vestibule was measured on the day before and 1, 4, and 7 days after surgery. Oral bacteria counts were statistically compared among time points and between intubation and extubation statuses. The oral bacteria counts on the tooth surface and buccal vestibule significantly increased from the day before surgery to 1 day after surgery, and then decreased from 1 to 4 days after surgery. On the day after surgery, the bacteria counts on the tooth surface and buccal vestibule were significantly higher in the intubated compared with the extubated group. Our findings suggest that the oral bacteria count is elevated just after surgery, especially if the patient has endotracheal intubation, which may increase the risk of aspiration pneumonia. These results highlight the importance of perioperative oral care to prevent postoperative pneumonia.

Quantification of nucleic acid quality in postmortem tissues from a cancer research autopsy program.

The last decade has seen a marked rise in the use of cancer tissues obtained from research autopsies. Such resources have been invaluable for studying cancer evolution or the mechanisms of therapeutic resistance to targeted therapies. Degradation of biomolecules is a potential challenge to usage of cancer tissues obtained in the post-mortem setting and remains incompletely studied. We analysed the nucleic acid quality in 371 different frozen tissue samples collected from 80 patients who underwent a research autopsy, including eight normal tissue types, primary and metastatic tumors. Our results indicate that RNA integrity number (RIN) of normal tissues decline with the elongation of post-mortem interval (PMI) in a tissue-type specific manner. Unlike normal tissues, the RNA quality of cancer tissues is highly variable with respect to post-mortem interval. The kinetics of DNA damage also has tissue type-specific features. Moreover, while DNA degradation is an indicator of low RNA quality, the converse is not true. Finally, we show that despite RIN values as low as 5.0, robust data can be obtained by RNA sequencing that reliably discriminates expression signatures.

Whole exome sequencing reveals recurrent mutations in BRCA2 and FAT genes in acinar cell carcinomas of the pancreas.

Acinar cell carcinoma of the pancreas is a rare tumor with a poor prognosis. Compared to pancreatic ductal adenocarcinoma, its molecular features are poorly known. We studied a total of 11 acinar cell carcinomas, including 3 by exome and 4 by target sequencing. Exome sequencing revealed 65 nonsynonymous mutations and 22 indels with a mutation rate of 3.4 mutations/Mb per tumor, on average. By accounting for not only somatic but also germline mutations with loss of the wild-type allele, we identified recurrent mutations of BRCA2 and FAT genes. BRCA2 showed somatic or germline premature termination mutations, with loss of the wild-type allele in 3 of 7 tumors. FAT1, FAT3, and FAT4 showed somatic or germline missense mutations in 4 of 7 tumors. The germline FAT mutations were with loss of the wild-type allele. Loss of BRCA2 expression was observed in 5 of 11 tumors. One patient with a BRCA2-mutated tumor experienced complete remission of liver metastasis following cisplatinum chemotherapy. In conclusion, acinar cell carcinomas show a distinct mutation pattern and often harbor somatic or germline mutations of BRCA2 and FAT genes. This result may warrant assessment of BRCA2 abrogation in patients with the carcinoma to determine their sensitivity to chemotherapy.

Clinicopathological significance of somatic RNF43 mutation and aberrant expression of ring finger protein 43 in intraductal papillary mucinous neoplasms of the pancreas.

Mutations in RNF43, which encodes the ubiquitin E3 ligase ring finger protein 43, were recently found in intraductal papillary mucinous neoplasms of the pancreas. We evaluated somatic mutations of RNF43 and the expression of ring finger protein 43 as well as their associations with the molecular and clinicopathological features in 176 surgically resected intraductal papillary mucinous neoplasms. Frozen tissues were available for 57 cases and were used for next-generation sequencing analysis of the entire coding exons of RNF43. Formalin-fixed and paraffin-embedded tissues from all 176 cases were used for the immunohistochemical analysis of the expression of ring finger protein 43. Mutations detected with the next-generation sequencing analysis were validated by using Sanger sequencing. Statistical analysis was used to evaluate the associations between RNF43 aberrations and molecular and clinicopathological features including GNAS mutations, KRAS mutations, loss of SMA and MAD4 homologue expression, tumor protein 53 overexpression, tumor grade, histological type, mural nodule detection, macroscopic type, stage, recurrence, and survival. Somatic RNF43 mutations were found in 8 (14%) of the 57 examined cases, and included 5 frameshift mutations (p.F69fs, p.S264fs, p.L311fs, p.R363fs, and p.V490fs), 1 non-sense mutation (p.Q153X), and 2 missense mutations (p.I164N and p.P310A). The expression of ring finger protein 43 was downregulated in 52 (29.5%) of the 176 examined cases. RNF43 mutations were significantly associated with the downregulated expression of ring finger protein 43 (P=0.011), GNAS mutation (P=0.020), and mural nodule detection (P=0.038). The expression of ring finger protein 43 was not associated with any clinicopathological features except RNF43 mutation. These results indicate that RNF43 mutation might cause downregulation of the expression of ring finger protein 43 and play a crucial role and associate synergistically with GNAS mutation during development of intraductal papillary mucinous neoplasm of the pancreas.

Protein phosphatase 6 controls BCR-induced apoptosis of WEHI-231 cells by regulating ubiquitination of Bcl-xL.

Crosslinking BCR in the immature B cell line WEHI-231 causes apoptosis. We found that Bcl-xL was degraded by polyubiquitination upon BCR crosslinking and in this study explored the mechanism that controls the degradation of Bcl-xL. Ser(62) of Bcl-xL was phosphorylated by JNK to trigger polyubiquitination, and this was opposed by serine/threonine protein phosphatase 6 (PP6) that physically associated with Bcl-xL. We show BCR crosslinking decreased PP6 activity to allow Ser(62) phosphorylation of Bcl-xL. CD40 crosslinking rescues BCR-induced apoptosis, and we found PP6 associated with CD40 and PP6 activation in response to CD40. Our data suggest that PP6 activity is regulated to control apoptosis by modulating Ser(62) phosphorylation of Bcl-xL, which results in its polyubiquitination and degradation.