Converged Rab37/IL-6 trafficking and STAT3/PD-1 transcription axes elicit an immunosuppressive lung tumor microenvironment.

Background: Increased IL-6 level, M2 macrophages and PD-1+CD8+ T cells in tumor microenvironments (TME) have been identified to correlate with resistance to checkpoint blockade immunotherapy, yet the mechanism remains poorly understood. Rab small GTPase-mediated trafficking of cytokines is critical in immuno-modulation. We have previously reported dysregulation of Rab37 in lung cancer cells, whereas the roles of Rab37 in tumor-infiltrating immune cells and cancer immunotherapy are unclear. Methods: The tumor growth of the syngeneic mouse allograft in wild type or Rab37 knockout mice was analyzed. Imaging analyses and vesicle isolation were conducted to determine Rab37-mediated IL-6 secretion. STAT3 binding sites at PD-1 promoter in T cells were identified by chromatin immunoprecipitation assay. Multiplex fluorescence immunohistochemistry was performed to detect the protein level of Rab37, IL-6 and PD-1 and localization of the tumor-infiltrating immune cells in allografts from mice or tumor specimens from lung cancer patients. Results: We revealed that Rab37 regulates the secretion of IL-6 in a GTPase-dependent manner in macrophages to trigger M2 polarization. Macrophage-derived IL-6 promotes STAT3-dependent PD-1 mRNA expression in CD8+ T cells. Clinically, tumors with high stromal Rab37 and IL-6 expression coincide with tumor infiltrating M2-macrophages and PD1+CD8+ T cells that predicts poor prognosis in lung cancer patients. In addition, lung cancer patients with an increase in plasma IL-6 level are found to be associated with immunotherapeutic resistance. Importantly, combined blockade of IL-6 and CTLA-4 improves survival of tumor-bearing mice by reducing infiltration of PD1+CD8+ T cells and M2 macrophages in TME. Conclusions: Rab37/IL-6 trafficking pathway links with IL-6/STAT3/PD-1 transcription regulation to foster an immunosuppressive TME and combined IL-6/CTLA-4 blockade therapy exerts potent anti-tumor efficacy.

Protein Phosphatase 2A in Lipopolysaccharide-Induced Cyclooxygenase-2 Expression in Murine Lymphatic Endothelial Cells.

The lymphatic endothelium plays an important role in the maintenance of tissue fluid homeostasis. It also participates in the pathogenesis of several inflammatory diseases. However, little is known about the underlying mechanisms by which lymphatic endothelial cell responds to inflammatory stimuli. In this study, we explored the mechanisms by which lipopolysaccharide (LPS) induces cyclooxygenase (COX)-2 expression in murine lymphatic endothelial cells (SV-LECs). LPS caused increases in cox-2 mRNA and protein levels, as well as in COX-2 promoter luciferase activity in SV-LECs. These actions were associated with protein phosphatase 2A (PP2A), apoptosis signal-regulating kinase 1 (ASK1), JNK1/2 and p38MAPK activation, and NF-κB subunit p65 and C/EBPß phosphorylation. PP2A-ASK1 signaling blockade reduced LPS-induced JNK1/2, p38MAPK, p65 and C/EBPß phosphorylation. Transfection with PP2A siRNA reduced LPS's effects on p65 and C/EBPß binding to the COX-2 promoter region. Transfected with the NF-κB or C/EBPß site deletion of COX-2 reporter construct also abrogated LPS's enhancing effect on COX-2 promoter luciferase activity in SV-LECs. Taken together, the induction of COX-2 in SV-LECs exposed to LPS may involve PP2A-ASK1-JNK and/or p38MAPK-NF-κB and/or C/EBPß cascade.

Clinical practice of endoscopic submucosal dissection for early colorectal neoplasms by a colonoscopist with limited gastric experience.

Objectives. Endoscopic submucosal dissection (ESD) for early colorectal neoplasms is regarded as a difficult technique and should commence after receiving the experiences of ESD in the stomach. The implementation of colorectal ESD in countries where early gastric cancer is uncommon might therefore be difficult. The aim is to delineate the feasibility and the learning curve of colorectal ESD performed by a colonoscopist with limited experience of gastric ESD. Methods. The first fifty cases of colorectal ESD, which were performed by a single colonoscopist between July 2010 and April 2013, were enrolled. Results. The mean of age was 64 (±9.204) years with mean size of neoplasm at 33 (±12.63) mm. The mean of procedure time was 70.5 (±48.9) min. The rates of en bloc resection, R0 resection, and curative resection were 86%, 86%, and 82%, respectively. Three patients had immediate perforation, but no patient developed delayed perforation or delayed bleeding. Conclusion. Our result disclosed that it is feasible for colorectal ESD to be performed by a colonoscopist with little experience of gastric ESD through satisfactory training and adequate case selection.

Carbon dioxide insufflation during withdrawal of the colonoscope improved postprocedure discomfort: a prospective, randomized, controlled trial.

In colonoscopy, the question of when and how to use carbon dioxide (CO(2)) insufflation remains uncertain. Inspection for the pathological changes during colonoscopy takes place during the withdrawal of the scope. This study aimed to determine whether CO(2) insufflation only at the withdrawal of the colonoscope has an effect comparable to that of CO(2) usage throughout the course of the procedure. Symptomatic patients were randomized in three groups: (1) patients given air insufflation (A; n = 33); (2) patients given CO(2) insufflation only at the time of scope withdrawal (CW; n = 33); and (3) patients given the CO(2) insufflation (C; n = 34) for the whole course of the colonoscopy. Patients were requested to answer questionnaires about their pain score during, at the end, and 1 h after the colonoscopy by using a pain numerical scale ranging from 0 to 10. The disparities of the pain score were noted at the end of the procedure and 1 h after the procedure (p = 0.026 and p < 0.001, respectively). We further analyzed the scores between two of the three groups. Both CW (vs. A; procedure end: p = 0.012, 1 h after: p = 0.001) and C (vs. A; procedure end: p = 0.072, 1 h after: p < 0.001) showed less postprocedure pain when compared with the group A. The pain score between CW and C were similar at each time segment (procedure end: p = 0.555, 1 h after: p = 0.491). CO(2) insufflation merely at the withdrawal of the colonoscope improved postprocedural abdominal discomfort and the effect was not inferior to that of full course CO(2) insufflation.

Radiofrequency ablation for treatment of hepatocellular carcinoma with cirrhosis.

BACKGROUND/AIMS: The majority of hepatocellular carcinoma patients with cirrhosis are not candidates for surgical resection, and local thermal therapy producing destruction of cancer cells was one of the ideal options for treatment. Heat from radiofrequency ablation is generated through agitation caused by an alternating electrical current. The heat of radiofrequency energy results in local cell coagulation and causes cellular ablation necrosis of tumor tissue. METHODOLOGY: Eighteen cases of hepatocellular carcinoma were treated with radiofrequency ablation in our institute. We used a RFA 2000 generator (Boston Scientific Co, USA) with LeVeen needle with the maximum diameter of 3.5 cm when the array electrodes were fanned out. The indications for this method included; i) normal prothrombin profile, ii) no ascites, iii) tumor can be detected and approached by ultrasound, iv) tumor cannot be resected or patient is not willing to take the operation. RESULTS: No specific complication was noted during or after the procedure. Only two cases needed more analgesics after the procedure. One case was found with burning of the stomach serosa proved by laparoscopic examination, in which radiofrequency ablation was performed to the tumor located in the left lobe of the segment 3. Impedance could not raise up completely in two cases with larger size tumor more than 5 cm. The decreased levels of alpha-fetoprotein were significant (P = 0.005) after radiofrequency ablation treatment. Residual tumor was found in four cases (20%) in the follow-up abdominal computed tomography scan. CONCLUSIONS: Radiofrequency ablation resulted in a higher rate of complete necrosis of tumor tissue and the complication rate was low as well. Therefore, we believed that radiofrequency ablation is an ideal treatment modality for most liver tumors, which cannot tolerate the conventional surgical procedures.