Endoscopic drainage of malignant distal biliary obstruction. Will ERCP no longer be necessary?

We read with interest the Editorial by Vila et al. on the paradigm shift for endoscopic biliary drainage of malignant distal biliary obstruction (MDBO) which places Endoscopic Ultrasound (EUS) drainage as the first option instead of traditional ERCP drainage. The modern biliary endoscopist must have the duodenoscope in one hand and the therapeutic echoendoscope in the other. ERCP training alone is no longer appropriate because the goal is to drain the obstruction during a single session. That is why in more and more centers the patient signs a single consent for endoscopic biliary drainage, whether by ERCP, EUS or combined. Should EUS drainage be used first for MDBO without attempting ERCP? A possible protocol for endoscopic drainage of MDBO could be to start with the duodenoscope for ERCP. If the papilla of Vater is accessible, try cannulation considering the ESGE criteria for a difficult cannulation: more than 5 contacts with the papilla; more than 5 minutes spent attempting to cannulate following visualization of the papilla; more than one unintended pancreatic duct cannulation or opacification. If biliary cannulation is not achieved, immediately switch to EUS drainage during the same session. Occasionally, the double guidewire technique or even transpancreatic biliary sphincterotomy could be used, but not needle-knife precut.

Use a biodegradable stent in ERCP and it will never be forgotten.

The easiest way to drain the bile duct or the main pancreatic duct by means of ERCP is the insertion of a plastic stent. Once cannulation has been achieved, which is generally the most complex and limiting step in ERCP, stent insertion is straightforward and rewarding. The main problem in benign pancreato-biliary conditions comes in the follow-up. Indications for biliary stent insertion in non-neoplastic diseases are common bile duct (CBD) stones that could not be completely extracted, benign strictures and leaks. In the pancreas stents are frequently inserted to prevent post-ERCP pancreatitis and for benign strictures and other less frequent conditions such as main pancreatic duct disruption. Currently in all centers more and more ERCPs are performed in patients without naive Papilla of Vater, generally for stent extraction or exchange. For example, in the recent study by Barakat and Banerjee, carried out in a tertiary care academic medical center, only 25% were index or initial ERCP, without previous sphincterotomy or stent, and subsequent procedures comprised the remaining 75 %.

Safety in digestive endoscopy during the ongoing COVID-19 pandemic.

We read with interest the study by Hernández-Camba et al. about the low value of antibody testing for COVID-19 before endoscopic procedures and we would like to make some comments. Nine months after the first state of alarm was declared in Spain due to the SARS-CoV-2 pandemic, we knew that infections in endoscopy staff were scarce if adequate protection was worn and non-urgent procedures were postponed in patients with an active infection. Therefore, the conclusions of the study currently appear to be self-evident. However, things were different at the time it was performed.

Straight plastic stents in tumors at the hepatic hilum and related duodenal perforations.

We read with interest the paper on the endoscopic treatment of a duodenal perforation related to a plastic biliary stent that was reported by Roa et al. We would like to add some comments about biliary stents inserted during endoscopic retrograde cholangiopancreatography (ERCP) to palliate malignant jaundice in hilar strictures. It is our belief that the most convenient strategy in non-operable patients should be the insertion of at least one uncovered self-expanding metal stent.

The best plastic pancreatic stent to prevent post-ERCP pancreatitis.

We consider very interesting the comments made by Serrano Díaz et al. on pancreatic stents inserted as prophylaxis for acute post-ERCP pancreatitis. As we recently stated in an editorial related to the prevention of this frequent complication, the aggressive way in which the pancreatic gland may respond to contact with the devices that are used for common bile duct cannulation via the papilla of Vater is almost philosophically surprising. It is our opinion that, usually, a pancreatic stent should only be inserted if the guidewire has spontaneously entered the main pancreatic duct (MPD). In ERCPs aiming at bile duct drainage, even when bile duct cannulation has been troublesome with extensive papillary manipulation, attempting cannulation of the MPD with the sole purpose of stent insertion can be more harmful than beneficial.

Regulation of the MDM2-p53 pathway by the ubiquitin ligase HERC2.

The p53 tumor suppressor protein is a transcription factor that plays a prominent role in protecting cells from malignant transformation. Protein levels of p53 and its transcriptional activity are tightly regulated by the ubiquitin E3 ligase MDM2, the gene expression of which is transcriptionally regulated by p53 in a negative feedback loop. The p53 protein is transcriptionally active as a tetramer, and this oligomerization state is modulated by a complex formed by NEURL4 and the ubiquitin E3 ligase HERC2. Here, we report that MDM2 forms a complex with oligomeric p53, HERC2, and NEURL4. HERC2 knockdown results in a decline in MDM2 protein levels without affecting its protein stability, as it reduces its mRNA expression by inhibition of its promoter activation. DNA damage induced by bleomycin dissociates MDM2 from the p53/HERC2/NEURL4 complex and increases the phosphorylation and acetylation of oligomeric p53 bound to HERC2 and NEURL4. Moreover, the MDM2 promoter, which contains p53-response elements, competes with HERC2 for binding of oligomeric, phosphorylated and acetylated p53. We integrate these findings in a model showing the pivotal role of HERC2 in p53-MDM2 loop regulation. Altogether, these new insights in p53 pathway regulation are of great interest in cancer and may provide new therapeutic targets.

HERCing: Structural and Functional Relevance of the Large HERC Ubiquitin Ligases.

Homologous to the E6AP carboxyl terminus (HECT) and regulator of chromosome condensation 1 (RCC1)-like domain-containing proteins (HERCs) belong to the superfamily of ubiquitin ligases. HERC proteins are divided into two subfamilies, Large and Small HERCs. Despite their similarities in terms of both structure and domains, these subfamilies are evolutionarily very distant and result from a convergence phenomenon rather than from a common origin. Large HERC genes, HERC1 and HERC2, are present in most metazoan taxa. They encode very large proteins (approximately 5,000 amino acid residues in a single polypeptide chain) that contain more than one RCC1-like domain as a structural characteristic. Accumulating evidences show that these unusually large proteins play key roles in a wide range of cellular functions which include neurodevelopment, DNA damage repair, and cell proliferation. To better understand the origin, evolution, and function of the Large HERC family, this minireview provides with an integrated overview of their structure and function and details their physiological implications. This study also highlights and discusses how dysregulation of these proteins is associated with severe human diseases such as neurological disorders and cancer.

The best approach to treat concomitant gallstones and common bile duct stones. Is ERCP still needed?

The authors analyze what should be the best approach to treat patients who had concomitant gallstones and common bile duct stones (CBDS). Laparoscopic common bile duct exploration (LCBDE) appears to be an atractive way to cure all kind of biliary stones in a single procedure. However, when scientific literature is reviewed most patients continue to need from ERCP for CBDS removal. ERCP can be performed before, after or during the same LC procedure. Patients with LCBDE had less pancreatitis rate because the Papilla of Vater is not manipulated but more bile leaks. Large CBDS continue to need, in general, from ERCP techniques.

Endoscopic biliary stenting: indications, choice of stents, and results: European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline - Updated October 2017.

ESGE recommends against routine preoperative biliary drainage in patients with malignant extrahepatic biliary obstruction; preoperative biliary drainage should be reserved for patients with cholangitis, severe symptomatic jaundice (e. g., intense pruritus), or delayed surgery, or for before neoadjuvant chemotherapy in jaundiced patients. Strong recommendation, moderate quality evidence. ESGE recommends the endoscopic placement of a 10-mm diameter self-expandable metal stent (SEMS) for preoperative biliary drainage of malignant extrahepatic biliary obstruction. Strong recommendation, moderate quality evidence.ESGE recommends SEMS insertion for palliative drainage of of extrahepatic malignant biliary obstruction. Strong recommendation, high quality evidence. ESGE recommends against the insertion of uncovered SEMS for the drainage of extrahepatic biliary obstruction of unconfirmed etiology. Strong recommendation, low quality evidence. ESGE suggests against routine preoperative biliary drainage in patients with malignant hilar obstruction. Weak recommendation, low quality evidence.ESGE recommends uncovered SEMSs for palliative drainage of malignant hilar obstruction. Strong recommendation, moderate quality evidence.ESGE recommends temporary insertion of multiple plastic stents or of a fully covered SEMS for treatment of benign biliary strictures. Strong recommendation, moderate quality evidence.ESGE recommends endoscopic placement of plastic stent(s) to treat bile duct leaks that are not due to transection of the common bile duct or common hepatic duct. Strong recommendation, moderate quality evidence.

Autophagic cell death associated to Sorafenib in renal cell carcinoma is mediated through Akt inhibition in an ERK1/2 independent fashion.

OBJECTIVES: To fully clarify the role of Mitogen Activated Protein Kinase in the therapeutic response to Sorafenib in Renal Cell Carcinoma as well as the cell death mechanism associated to this kinase inhibitor, we have evaluated the implication of several Mitogen Activated Protein Kinases in Renal Cell Carcinoma-derived cell lines. MATERIALS AND METHODS: An experimental model of Renal Cell Carcinoma-derived cell lines (ACHN and 786-O cells) was evaluated in terms of viability by MTT assay, induction of apoptosis by caspase 3/7 activity, autophagy induction by LC3 lipidation, and p62 degradation and kinase activity using phospho-targeted antibodies. Knock down of ATG5 and ERK5 was performed using lentiviral vector coding specific shRNA. RESULTS: Our data discard Extracellular Regulated Kinase 1/2 and 5 as well as p38 Mitogen Activated Protein Kinase pathways as mediators of Sorafenib toxic effect but instead indicate that the inhibitory effect is exerted through the PI3K/Akt signalling pathway. Furthermore, we demonstrate that inhibition of Akt mediates cell death associated to Sorafenib without caspase activation, and this is consistent with the induction of autophagy, as indicated by the use of pharmacological and genetic approaches. CONCLUSION: The present report demonstrates that Sorafenib exerts its toxic effect through the induction of autophagy in an Akt-dependent fashion without the implication of Mitogen Activated Protein Kinase. Therefore, our data discard the use of inhibitors of the RAF-MEK-ERK1/2 signalling pathway in RCC and support the use of pro-autophagic compounds, opening new therapeutic opportunities for Renal Cell Carcinoma.

Enhancing the current evidence on endoscopist-directed propofol-based sedation.

During the last years, there is more and more scientific evidence about the safety and feasibility of non-anesthesiologist administration of propofol (NAAP) in gastrointestinal endoscopy, reducing sedation induction and recovery time as well as increasing patient and endoscopist satisfaction. Furthermore, a similar risk of adverse events compared with traditional agents or anesthesiologist administration of propofol (AAP) has been described. The present special issue of the Spanish Journal of Gastroenterology (Revista Española de Enfermedades Digestivas) focusses on NAAP in different settings, including complex endoscopic procedures.

Implication of VHL, ERK5, and HIF-1alpha in clear cell renal cell carcinoma: Molecular basis.

OBJECTIVES: To determine the expression status of several proteins related to VHL gene function and its relationship with common clinicopathological parameters. MATERIAL AND METHODS: Observational, analytical, cross-sectional study with 50 patients diagnosed with clear cell renal cell carcinoma. The study analyzed VHL mutations and hypermethylation as well as protein expression of VHL, CA-IX, HIF-1alpha, VEGF, ERK1/2, and ERK5, relating them to clinical variables. A bivariate and multivariate descriptive logistical regression analysis was performed, using the presence of metastasis at diagnosis as dependent variable. RESULTS: The study identified 13 (26%) VHL mutations related to nuclear grade (P = 0.036). VHL hypermethylation was found in 20% of cases. VHL expression was associated with the presence of mutations (P = 0.013), and the absence of expression was associated with nuclear grade and the presence of metastasis (P<0.05). HIF-1alpha was negative in only 5 cases. Vascular endothelial growth factor (VEGF) was positive in 31 of 47 cases and was associated with Fuhrman nuclear grade, presence of metastasis, and stage (P<0.05). ERK5 expression was increased in 58% of cases and associated with the presence of metastasis and more advanced stages (P<0.05). In the logistic regression analysis, the only variable remaining in the model was VEGF expression (P = 0.014). CONCLUSIONS: VEGF has prognostic value in clear cell renal cell carcinoma, and ERK5 may be a new prognostic marker in this type of tumor owing to its relationship with metastasis and more advanced stages.

p38MAPK and Chemotherapy: We Always Need to Hear Both Sides of the Story.

The p38MAPK signaling pathway was initially described as a stress response mechanism. In fact, during previous decades, it was considered a pathway with little interest in oncology especially in comparison with other MAPKs such as ERK1/2, known to be target of oncogenes like Ras. However, its involvement in apoptotic cell death phenomena makes this signaling pathway more attractive for many cancer research laboratories. This apoptotic role allows to establish a link between p38MAPK and regular chemotherapeutic agents such as Cisplatin or base analogs (Cytarabine, Gemcitabine or 5-Fluorouracil) which are currently used in hospitals across the world. In fact, and more recently, p38MAPK has also been connected with targeted therapies like tyrosine kinase inhibitors (vg. Imatinib, Sorafenib) and, to a lesser extent, with monoclonal antibodies. In addition, the oncogenic or tumor suppressor potential of this signaling pathway has aroused the interest of the scientific community in evaluating p38MAPK as a novel target for cancer therapy. In this review, we will summarize the role of p38MAPK in chemotherapy as well as the potential that p38MAPK inhibition can bring to cancer therapy. All the evidences suggest that p38MAPK could be a double-edged sword and that the search for the most appropriate candidate patients, depending on their pathology and treatment, will lead to a more rational use of this new therapeutic tool.

MKP1 mediates chemosensitizer effects of E1a in response to cisplatin in non-small cell lung carcinoma cells.

The adenoviral gene E1a is known to enhance the antitumor effect of cisplatin, one of the cornerstones of the current cancer chemotherapy. Here we study the molecular basis of E1a mediated sensitivity to cisplatin in an experimental model of Non-small cell lung cancer. Our data show how E1a blocks the induction of autophagy triggered by cisplatin and promotes the apoptotic response in resistant cells. Interestingly, at the molecular level, we present evidences showing how the phosphatase MKP1 is a major determinant of cisplatin sensitivity and its upregulation is strictly required for the induction of chemosensitivity mediated by E1a. Indeed, E1a is almost unable to promote sensitivity in H460, in which the high expression of MKP1 remains unaffected by E1a. However, in resistant cell as H1299, H23 or H661, which display low levels of MKP1, E1a expression promotes a dramatic increase in the amount of MKP1 correlating with cisplatin sensitivity. Furthermore, effective knock down of MKP1 in H1299 E1a expressing cells restores resistance to a similar extent than parental cells.  In summary, the present work reinforce the critical role of MKP1 in the cellular response to cisplatin highlighting the importance of this phosphatase in future gene therapy approach based on E1a gene.

Exploiting the potential of autophagy in cisplatin therapy: A new strategy to overcome resistance.

Resistance to cisplatin is a major challenge in the current cancer therapy. In order to explore new therapeutic strategies to cisplatin resistance, we evaluated, in a model of lung cancer (H1299 and H460 cell lines), the nature of the pathways leading to cell death. We observed that H1299 displayed a natural resistance to cisplatin due to an inability to trigger an apoptotic response that correlates with the induction of autophagy. However, pharmacological and genetic approaches showed how autophagy was a mechanism associated to cell death rather than to resistance. Indeed, pro-autophagic stimuli such as mTOR or Akt inhibition mediate cell death in both cell lines to a similar extent. We next evaluated the response to a novel platinum compound, monoplatin, able to promote cell death in an exclusive autophagy-dependent manner. In this case, no differences were observed between both cell lines. Furthermore, in response to monoplatin, two molecular hallmarks of cisplatin response (p53 and MAPKs) were not implicated, indicating the ability of this pro-autophagic compound to overcome cisplatin resistance. In summary, our data highlight how induction of autophagy could be used in cisplatin resistant tumours and an alternative treatment for p53 mutated patient in a synthetic lethally approach.

Perforation in colorectal stenting: a meta-analysis and a search for risk factors.

BACKGROUND: Recent studies suggest that there is a substantial risk of perforation after colorectal stent placement. OBJECTIVE: To identify risk factors for perforation from colonic stenting. DESIGN: A meta-analysis of 86 studies published between 2005 and 2011. SETTING: Multicenter review. PATIENTS: All patients who underwent colorectal stent placement. INTERVENTION: Colorectal stent placement. MAIN OUTCOME MEASUREMENTS: The occurrence of perforation with subgroup analyses for stent design, stricture etiology, stricture dilation, and concomitant chemotherapy, including the use of bevacizumab. RESULTS: A total of 4086 patients underwent colorectal stent placement; perforation occurred in 207. Meta-analysis revealed an overall perforation rate of 7.4%. Of the 9 most frequently used stent types, the WallFlex, the Comvi, and the Niti-S D-type had a higher perforation rate (>10%). A lower perforation rate (<5%) was found for the Hanarostent and the Niti-S covered stent. Stenting benign strictures was associated with a significantly increased perforation rate of 18.4% compared with 7.5% for malignant strictures. Dilation did not increase the risk of perforation: 8.5% versus 8.5% without dilation. The subgroup of post-stent placement dilation had a significantly increased perforation risk of 20.4%. With a perforation rate of 12.5%, bevacizumab-based therapy was identified as a risk factor for perforation, whereas the risk for chemotherapy without bevacizumab was 7.0% and not increased compared with the group without concomitant therapies during stent therapy (9.0%). LIMITATIONS: Heterogeneity; a considerable proportion of data is unavailable for subgroup analysis. CONCLUSIONS: The perforation rate of colonic stenting is 7.4%. Stent design, benign etiology, and bevacizumab were identified as risk factors for perforation. Intraprocedural stricture dilation and concomitant chemotherapy were not associated with an increased risk of perforation.

E1a promotes c-Myc-dependent replicative stress: implications in glioblastoma radiosensitization.

The E1a gene from adenovirus is known to be a potent inducer of chemo/radiosensitivity in a wide range of tumors. However, the molecular bases of its radiosensitizer properties are still poorly understood. In an attempt to study this effect, U87MG cells, derived from a radio-resistant tumor as glioblastoma, where infected with lentivirus carrying E1a gene developing an acute sensitivity to ionizing radiation. The induction of radiosensitivity correlated with a marked G 2/M phase accumulation and a potent apoptotic response. Our findings demonstrate that c-Myc plays a pivotal role in E1a-associated radiosensitivity through the induction of a replicative stress situation, as our data support by genetic approaches, based in interference and overexpression in U87MG cells. In fact, we present evidence showing that Chk1 is a novel transcriptional target of E1a gene through the effect exerted by this adenoviral protein onto c-Myc. Moreover, c-Myc upregulation also explains the marked phosphorylation of H2AX associated to E1a expression in the absence of DNA damage. Indeed, all these observations were applicable to other experimental models, such as T98G, LN-405 and A172, rendering the same pattern in terms of radiosensitivity, cell cycle distribution, upregulation of Chk1, c-Myc, and phosphorylation pattern of H2AX. In summary, our data propose a novel mechanism to explain how E1a mediates radiosensitivity through the signaling axis E1a→c-Myc→ replicative stress situation. This novel mechanism of E1a-mediated radiosensitivity could be the key to open new possibilities in the current therapy of glioblastoma.

Colorectal stenting as first-line treatment in acute colonic obstruction.

Tumoral obstructions in almost the entire gastrointestinal tract can be resolved with interventional digestive endoscopy techniques. Self-expanding metal stent (SEMS) insertion in the obstructed colon is a minimally invasive and relatively simple procedure providing an effective first-line treatment for relief of acute malignant obstruction symptoms and serving either as a preoperative or "bridge to surgery" procedure or as palliative definitive care. This technique was introduced in the early 1990s. Although there is still debate about its real value, a lot of reports have been published since then and the procedure is advocated by many surgical groups as the method of choice for the initial treatment of left-sided tumoral colonic obstruction. Before the procedure, colonic obstruction has to be diagnosed by abdominal radiographs, water contrast enema and/or a computed tomography scan. The greatest information is provided by the latter and it is perhaps the method of choice prior to stenting. Skills and training are mandatory, as in all interventional procedures. The key step for success is to cross the malignant stricture with a guidewire. Care must be taken not to over insufflate an obstructed colon during the procedure. SEMS slide over the guidewire through the endoscope working channel or in parallel, outside the endoscope. An average 7% perforation rate has been reported during the procedure and other minor complications can appear in the follow up. However, as a whole, this technique seems to compare favorably with surgery.

ERK5/BMK1 is a novel target of the tumor suppressor VHL: implication in clear cell renal carcinoma.

Extracellular signal-regulated kinase 5 (ERK5), also known as big mitogen-activated protein kinase (MAPK) 1, is implicated in a wide range of biologic processes, which include proliferation or vascularization. Here, we show that ERK5 is degraded through the ubiquitin-proteasome system, in a process mediated by the tumor suppressor von Hippel-Lindau (VHL) gene, through a prolyl hydroxylation-dependent mechanism. Our conclusions derive from transient transfection assays in Cos7 cells, as well as the study of endogenous ERK5 in different experimental systems such as MCF7, HMEC, or Caki-2 cell lines. In fact, the specific knockdown of ERK5 in pVHL-negative cell lines promotes a decrease in proliferation and migration, supporting the role of this MAPK in cellular transformation. Furthermore, in a short series of fresh samples from human clear cell renal cell carcinoma, high levels of ERK5 correlate with more aggressive and metastatic stages of the disease. Therefore, our results provide new biochemical data suggesting that ERK5 is a novel target of the tumor suppressor VHL, opening a new field of research on the role of ERK5 in renal carcinomas.