Triplex DNA-binding proteins are associated with clinical outcomes revealed by proteomic measurements in patients with colorectal cancer

BACKGROUND: Tri- and tetra-nucleotide repeats in mammalian genomes can induce formation of alternative non-B DNA structures such as triplexes and guanine (G)-quadruplexes. These structures can induce mutagenesis, chromosomal translocations and genomic instability. We wanted to determine if proteins that bind triplex DNA structures are quantitatively or qualitatively different between colorectal tumor and adjacent normal tissue and if this binding activity correlates with patient clinical characteristics. METHODS: Extracts from 63 human colorectal tumor and adjacent normal tissues were examined by gel shifts (EMSA) for triplex DNA-binding proteins, which were correlated with clinicopathological tumor characteristics using the Mann-Whitney U, Spearman’s rho, Kaplan-Meier and Mantel-Cox log-rank tests. Biotinylated triplex DNA and streptavidin agarose affinity binding were used to purify triplex-binding proteins in RKO cells. Western blotting and reverse-phase protein array were used to measure protein expression in tissue extracts. RESULTS: Increased triplex DNA-binding activity in tumor extracts correlated significantly with lymphatic disease, metastasis, and reduced overall survival. We identified three multifunctional splicing factors with biotinylated triplex DNA affinity: U2AF65 in cytoplasmic extracts, and PSF and p54nrb in nuclear extracts. Super-shift EMSA with anti-U2AF65 antibodies produced a shifted band of the major EMSA H3 complex, identifying U2AF65 as the protein present in the major EMSA band. U2AF65 expression correlated significantly with EMSA H3 values in all extracts and was higher in extracts from Stage III/IV vs. Stage I/II colon tumors (p = 0.024). EMSA H3 values and U2AF65 expression also correlated significantly with GSK3 beta, beta-catenin, and NF- B p65 expression, whereas p54nrb and PSF expression correlated with c-Myc, cyclin D1, and CDK4. EMSA values and expression of all three splicing factors correlated with ErbB1, mTOR, PTEN, and Stat5. Western blots confirmed that full-length and truncated beta-catenin expression correlated with U2AF65 expression in tumor extracts. CONCLUSIONS: Increased triplex DNA-binding activity in vitro correlates with lymph node disease, metastasis, and reduced overall survival in colorectal cancer, and increased U2AF65 expression is associated with total and truncated beta-catenin expression in high-stage colorectal tumors

Exercise Improves Outcomes of Surgery on Fatty Liver in Mice: A Novel Effect Mediated by the AMPK Pathway.

OBJECTIVE To investigate whether exercise improves outcomes of surgery on fatty liver, and whether pharmacological approaches can substitute exercising programs. SUMMARY OF BACKGROUND DATA Steatosis is the hepatic manifestation of the metabolic syndrome, and decreases the liver's ability to handle inflammatory stress or to regenerate after tissue loss. Exercise activates adenosine monophosphate-activated kinase (AMPK) and mitigates steatosis; however, its impact on ischemia-reperfusion injury and regeneration is unknown. METHODS We used a mouse model of simple, diet-induced steatosis and assessed the impact of exercise on metabolic parameters, ischemia-reperfusion injury and regeneration after hepatectomy. The same parameters were evaluated after treatment of mice with the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). Mice on a control diet served as age-matched controls. RESULTS A 4-week-exercising program reversed steatosis, lowered insulin levels, and improved glucose tolerance. Exercise markedly enhanced the ischemic tolerance and the regenerative capacity of fatty liver. Replacing exercise with AICAR was sufficient to replicate the above benefits. Both exercise and AICAR improved survival after extended hepatectomy in mice challenged with a Western diet, indicating protection from resection-induced liver failure. CONCLUSIONS Exercise efficiently counteracts the metabolic, ischemic, and regenerative deficits of fatty liver. AICAR acts as an exercise mimetic in settings of fatty liver disease, an important finding given the compliance issues associated with exercise. Exercising, or its substitution through AICAR, may provide a feasible strategy to negate the hepatic consequences of energy-rich diet, and has the potential to extend the application of liver surgery if confirmed in humans

Ablation Strategies for Locally Advanced Pancreatic Cancer

With the advent of novel and somewhat effective chemotherapy against pancreas cancer, several groups developed a new interest on locally advanced pancreatic cancer (LAPC). Unresectable tumors constitute up to 80% of pancreatic cancer (PC) at the time of diagnosis and are associated with a 5-year overall survival of less than 5%. To control those tumors locally, with perhaps improved patients survival, significant advances were made over the last 2 decades in the development of ablation methods including cryoablation, radiofrequency ablation, microwave ablation, high intensity focused ultrasound and irreversible electroporation (IRE). Many suggested a call for caution for possible severe or lethal complications in using such techniques on the pancreas. Most fears were on the heating or freezing of the pancreas, while non-thermal ablation (IRE) could offer safer approaches. The multimodal therapies along with high-resolution imaging guidance have created some enthusiasm toward ablation for LAPC. The impact of ablation techniques on primarily non-resectable PC remains, however, unclear

The DNA hypermethylation phenotype of colorectal cancer liver metastases resembles that of the primary colorectal cancers

BACKGROUND Identifying molecular differences between primary and metastatic colorectal cancers-now possible with the aid of omics technologies-can improve our understanding of the biological mechanisms of cancer progression and facilitate the discovery of novel treatments for late-stage cancer. We compared the DNA methylomes of primary colorectal cancers (CRCs) and CRC metastases to the liver. Laser microdissection was used to obtain epithelial tissue (10 to 25 × 10$^{6}$ μm$^{2}$) from sections of fresh-frozen samples of primary CRCs (n = 6), CRC liver metastases (n = 12), and normal colon mucosa (n = 3). DNA extracted from tissues was enriched for methylated sequences with a methylCpG binding domain (MBD) polypeptide-based protocol and subjected to deep sequencing. The performance of this protocol was compared with that of targeted enrichment for bisulfite sequencing used in a previous study of ours. RESULTS MBD enrichment captured a total of 322,551 genomic regions (249.5 Mb or ~ 7.8% of the human genome), which included over seven million CpG sites. A few of these regions were differentially methylated at an expected false discovery rate (FDR) of 5% in neoplastic tissues (primaries: 0.67%, i.e., 2155 regions containing 279,441 CpG sites; liver metastases: 1%, i.e., 3223 regions containing 312,723 CpG sites) as compared with normal mucosa samples. Most of the differentially methylated regions (DMRs; 94% in primaries; 70% in metastases) were hypermethylated, and almost 80% of these (1882 of 2396) were present in both lesion types. At 5% FDR, no DMRs were detected in liver metastases vs. primary CRC. However, short regions of low-magnitude hypomethylation were frequent in metastases but rare in primaries. Hypermethylated DMRs were far more abundant in sequences classified as intragenic, gene-regulatory, or CpG shelves-shores-island segments, whereas hypomethylated DMRs were equally represented in extragenic (mainly, open-sea) and intragenic (mainly, gene bodies) sequences of the genome. Compared with targeted enrichment, MBD capture provided a better picture of the extension of CRC-associated DNA hypermethylation but was less powerful for identifying hypomethylation. CONCLUSIONS Our findings demonstrate that the hypermethylation phenotype in CRC liver metastases remains similar to that of the primary tumor, whereas CRC-associated DNA hypomethylation probably undergoes further progression after the cancer cells have migrated to the liver

Advances in liver surgery for cholangiocarcinoma

PURPOSE OF REVIEW: The purpose of this review is to evaluate the most current strategies of surgical treatment for cholangiocarcinoma including liver resection and transplantation. RECENT FINDINGS: More aggressive surgical approaches have emerged over the past decade to treat patients previously considered to have unresectable lesions, which include combined hepatectomy with vascular resection, liver mass manipulation, oncological nontouch technique and liver transplantation. SUMMARY: Cholangiocarcinoma can occur anywhere along the biliary system. Its detection rate, and consequently its incidence, has risen possibly because of improvements in diagnostic imaging. Cholangiocarcinomas are presently understood within three distinct categories: intrahepatic, perihilar and distal tumors. The perihilar type is the most common, followed by the distal and intrahepatic types. This division has therapeutic relevance because the type of surgery depends on the anatomical location and extension of the tumor. This review will primarily focus on those circumstances in which a hepatectomy is required, which provides the greatest chance of cure. In this setting, liver transplantation for perihilar cholangiocarcinoma has resurged as an excellent option for a selective group of patients, when associated with a neoadjuvant chemoradiation protocol. Despite more aggressive surgical approaches, many cases remain unresectable with a poor prognosis

Timing of surgical repair of bile duct injuries after laparoscopic cholecystectomy: A systematic review

Background: The surgical management of bile duct injuries (BDIs) after laparoscopic cholecystectomy (LC) is challenging and the optimal timing of surgery remains unclear. The primary aim of this study was to systematically evaluate the evidence behind the timing of BDI repair after LC in the literature. Aim: To assess timing of surgical repair of BDI and postoperative complications. Methods: The MEDLINE, EMBASE, and The Cochrane Library databases were systematically screened up to August 2021. Risk of bias was assessed via the Newcastle Ottawa scale. The primary outcomes of this review included the timing of BDI repair and postoperative complications. Results: A total of 439 abstracts were screened, and 24 studies were included with 15609 patients included in this review. Of the 5229 BDIs reported, 4934 (94%) were classified as major injury. Timing of bile duct repair was immediate (14%, n = 705), early (28%, n = 1367), delayed (28%, n = 1367), or late (26%, n = 1286). Standardization of definition for timing of repair was remarkably poor among studies. Definitions for immediate repair ranged from < 24 h to 6 wk after LC while early repair ranged from < 24 h to 12 wk. Likewise, delayed (> 24 h to > 12 wk after LC) and late repair (> 6 wk after LC) showed a broad overlap. Conclusion: The lack of standardization among studies precludes any conclusive recommendation on optimal timing of BDI repair after LC. This finding indicates an urgent need for a standardized reporting system of BDI repair

Liver-fat and liver-function indices derived from Gd-EOB-DTPA-enhanced liver MRI for prediction of future liver remnant growth after portal vein occlusion

OBJECTIVES To evaluate the use of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI)-derived fat- and liver function-measurements for prediction of future liver remnant (FLR) growth after portal vein occlusion (PVO) in patients scheduled for major liver resection. METHODS Forty-five patients (age, 59 ± 13.9 y) who underwent Gd-EOB-DTPA-enhanced liver MRI within 24 ± 18 days prior to PVO were included in this study. Fat-Signal-Fraction (FSF), relative liver enhancement (RLE) and corrected liver-to-spleen ratio (corrLSR) of the FLR were calculated from in- and out-of-phase (n=42) as well as from unenhanced T1-weighted, and hepatocyte-phase images (n=35), respectively. Kinetic growth rate (KGR, volume increase/week) of the FLR after PVO was the primary endpoint. Receiver operating characteristics analysis was used to determine cutoff values for prediction of impaired FLR-growth. RESULTS FSF (%) showed significant inverse correlation with KGR (r=-0.41, p=0.008), whereas no significant correlation was found with RLE and corrLSR. FSF was significantly higher in patients with impaired FLR-growth than in those with normal growth (%FSF, 8.1 ± 9.3 vs. 3.0 ± 5.9, p=0.02). ROC-analysis revealed a cutoff-FSF of 4.9% for identification of patients with impaired FLR-growth with a specificity of 82% and sensitivity of 47% (AUC 0.71 [95%CI:0.54-0.87]). Patients with impaired FLR-growth according to the FSF-cutoff showed a tendency towards higher postoperative complication rates (posthepatectomy liver failure in 50% vs. 19%). CONCLUSIONS Liver fat-content, but not liver function derived from Gd-EOB-DTPA-enhanced MRI is a predictor of FLR-growth after PVO. Thus, liver MRI could help in identifying patients at risk for insufficient FLR-growth, who may need re-evaluation of the therapeutic strategy

Intraoperative adverse events during irreversible electroporation-a call for caution

BACKGROUND Irreversible electroporation is increasingly used for treatment of solid tumors, but safety data remain scarce. This study aimed to describe intraoperative adverse events associated with irreversible electroporation in patients undergoing solid tumor ablation. METHODS We analyzed demographic and intraoperative data for patients (n = 43) undergoing irreversible electroporation for hepato-pancreato-biliary and retroperitoneal malignancies (2012 to 2015). Adverse events were defined as cardiac, surgical, or equipment-related. RESULTS Adverse events (n = 20, 47%) were primarily cardiac (90%, n = 18), including blood pressure elevation (77%, n = 14/18) and arrhythmia (16%, n = 7/43). All but one was managed medically, 1 patient with arrhythmia required termination of ablation. Bleeding and technical problems with the equipment occurred in 1 patient each. Multivariable analysis revealed previous cardiovascular disease and needle placement close to the celiac trunk associated with increased likelihood for cardiac events. CONCLUSIONS Intraoperative cardiac adverse events are common during irreversible electroporation but rarely impair completion of the procedure

Novel Benefits of Remote Ischemic Preconditioning Through VEGF-dependent Protection From Resection-induced Liver Failure in the Mouse

OBJECTIVE To investigate the impact of remote ischemic preconditioning (RIPC) on liver regeneration after major hepatectomy. SUMMARY BACKGROUND DATA RIPC is a strategy applied at remote sites to mitigate ischemic injury. Unlike other preconditioning approaches, RIPC spares target organs as it acts via systemic VEGF elevations. In the liver, however, VEGF is an important driver of regeneration following resection. Therefore, RIPC may have pro-regenerative effects. METHODS RIPC was applied to C57BL/6 mice through intermittent clamping of the femoral vessels prior to standard 68%-hepatectomy or extended 86%-hepatectomy, with the latter causing liver failure and impaired survival. Liver regeneration was assessed through weight gain, proliferative markers (Ki67, pH3, mitoses), cell cycle-associated molecules, and survival. The role of the VEGF-ID1-WNT2 signaling axis was assessed through WIF1 (a WNT antagonist) and recombinant WNT2 injected prior to hepatectomy. RESULTS RIPC did not affect regeneration after 68%-hepatectomy, but improved liver weight gain and hepatocyte mitoses after 86%-hepatectomy. Importantly, RIPC raised survival from 40% to 80% after 86%-hepatectomy, indicating the promotion of functional recovery. Mechanistically, the RIPC-induced elevations in VEGF were accompanied by increases in the endothelial transcription factor Id1, its target WNT2, and its hepatocellular effector β-catenin. WIF1 injection prior to 86%-hepatectomy abrogated the RIPC benefits, while recombinant WNT2 had pro-regenerative effects akin to RIPC. CONCLUSION RIPC improves the regenerative capacity of marginal liver remnants in a VEGF-dependent way. If confirmed in patients, RIPC may become the preconditioning strategy of choice in the setting of extended liver resections