Clinical significance and functional role of adhesion G-protein-coupled receptors in human pancreatic ductal adenocarcinoma.

BACKGROUND: The adhesion G-protein-coupled receptors (GPCRs) play crucial roles in tumour pathogenesis, however, their clinical significance in pancreatic ductal adenocarcinoma (PDAC) remains unclear. METHODS: We analysed 796 PDAC patients, including 331 from public data sets (TCGA, ICGC and GSE57495) and 465 from independent cohorts (training: n = 321, validation: n = 144). Using in-vitro studies, we confirmed the biological function of the candidate GPCRs. RESULTS: Analysis of all 33 adhesion GPCRs, led to identify GPR115, as the only significant prognostic factor in all public data sets. The patients with high GPR115 expression exhibited significantly poorer prognosis for OS and RFS, in training (P < 0.01, P < 0.01) and validation cohort (P < 0.01, P = 0.04). Multivariate analysis indicated that GPR115 high expression was an independent prognostic factor in both cohorts (HR = 1.43; P = 0.01, HR = 2.55; P < 0.01). A risk-prediction model using Cox regression by incorporating GPR115 and clinicopathological factors accurately predicted 5-year survival following surgery. In addition, GPR115 silencing inhibited cell proliferation and migration in PDAC cells. CONCLUSION: We demonstrated that GPR115 has important prognostic significance and functional role in tumour progression; providing a rationale that this may be a potential therapeutic target in patients with PDAC.

A Liquid Biopsy Signature for the Detection of Patients With Early-Onset Colorectal Cancer.

BACKGROUND & AIMS: Early-onset colorectal cancer (EOCRC) is a distinct clinical and molecular entity with poor survival outcomes compared with late-onset CRC. Although the incidence of EOCRC is rising, current CRC screening strategies have several limitations in diagnostic performance for EOCRC. In view of this clinical challenge, novel and robust biomarkers for detection of EOCRC are necessary. The aim of this study was to develop a circulating micro RNA (miRNA) signature for the diagnosis of patients with EOCRC. METHODS: A systematic discovery approach by analyzing a large, publicly available, noncoding RNA expression profiling dataset (GSE115513) was used. A panel of miRNAs was identified, which was subsequently validated in blood samples from patients with EOCRC in 2 independent cohorts (n = 149) compared with controls (n = 110) and pre/postoperative plasma specimens (n = 22) using quantitative reverse-transcription polymerase chain reaction assays. RESULTS: In the discovery phase, 4 miRNAs were found to be expressed in blood samples. A combination signature of these 4 miRNAs (miR-193a-5p, miR-210, miR-513a-5p, and miR-628-3p) yielded an area under the curve of 0.92 (95% confidence interval, 0.85-0.96) for identification of EOCRC in the training cohort. The miRNA panel performance was then confirmed in an independent validation cohort (area under the curve, 0.88; 95% confidence interval, 0.82-0.93). Moreover, the miRNA panel robustly identified patients with early-stage EOCRC (P < .001). The decreased expression of miRNAs in postsurgery plasma specimens indicated their tumor specificity. CONCLUSIONS: Our novel miRNA signature for the diagnosis of EOCRC has the potential to identify patients with EOCRC with high accuracy for clinical application in the noninvasive diagnosis of EOCRC.

An Exosome-based Transcriptomic Signature for Noninvasive, Early Detection of Patients With Pancreatic Ductal Adenocarcinoma: A Multicenter Cohort Study.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) incidence is rising worldwide, and most patients present with an unresectable disease at initial diagnosis. Measurement of carbohydrate antigen 19-9 (CA19-9) levels lacks adequate sensitivity and specificity for early detection; hence, there is an unmet need to develop alternate molecular diagnostic biomarkers for PDAC. Emerging evidence suggests that tumor-derived exosomal cargo, particularly micro RNAs (miRNAs), offer an attractive platform for the development of cancer-specific biomarkers. Herein, genomewide profiling in blood specimens was performed to develop an exosome-based transcriptomic signature for noninvasive and early detection of PDAC. METHODS: Small RNA sequencing was undertaken in a cohort of 44 patients with an early-stage PDAC and 57 nondisease controls. Using machine-learning algorithms, a panel of cell-free (cf) and exosomal (exo) miRNAs were prioritized that discriminated patients with PDAC from control subjects. Subsequently, the performance of the biomarkers was trained and validated in independent cohorts (n = 191) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. RESULTS: The sequencing analysis initially identified a panel of 30 overexpressed miRNAs in PDAC. Subsequently using qRT-PCR assays, the panel was reduced to 13 markers (5 cf- and 8 exo-miRNAs), which successfully identified patients with all stages of PDAC (area under the curve [AUC] = 0.98 training cohort; AUC = 0.93 validation cohort); but more importantly, was equally robust for the identification of early-stage PDAC (stages I and II; AUC = 0.93). Furthermore, this transcriptomic signature successfully identified CA19-9 negative cases (<37 U/mL; AUC = 0.96), when analyzed in combination with CA19-9 levels, significantly improved the overall diagnostic accuracy (AUC = 0.99 vs AUC = 0.86 for CA19-9 alone). CONCLUSIONS: In this study, an exosome-based liquid biopsy signature for the noninvasive and robust detection of patients with PDAC was developed.

Activating transcription factor 5 (ATF5) controls intestinal tuft and goblet cell expansion upon succinate-induced type 2 immune responses in mice.

Intestinal tuft cells, a chemosensory cell type in mucosal epithelia that secrete interleukin (IL)-25, play a pivotal role in type 2 immune responses triggered by parasitic infections. Tuft cell-derived IL-25 activates type 2 innate lymphoid cells (ILC2) to secrete IL-13, which, in turn, acts on intestinal stem or transient amplifying cells to expand tuft cells themselves and mucus-secreting goblet cells. However, the molecular mechanisms of tuft cell differentiation under type 2 immune responses remain unclear. The present study investigated the effects of the deletion of activating transcription factor 5 (ATF5) on the type 2 immune response triggered by succinate (a metabolite of parasites) in mice. ATF5 mRNAs were expressed in the small intestine, and the loss of the ATF5 gene did not affect the gross morphology of the tissue or the basal differentiation of epithelial cell subtypes. Succinate induced marked increases in tuft and goblet cell numbers in the ATF5-deficient ileum. Tuft cells in the ATF5-deficient ileum are assumed to be a subtype of intestinal tuft cells (Tuft-2 cells) marked by the transcription factor Spib. Exogenous IL-25 induced similar increases in tuft and goblet cell numbers in wild-type and ATF5-deficient ilea. IL-13 at a submaximal dose enhanced tuft cell differentiation more in ATF5-deficient than in wild-type intestinal organoids. These results indicate that the loss of ATF5 enhanced the tuft cell-ILC2 type 2 immune response circuit by promoting tuft cell differentiation in the small intestine, suggesting its novel regulatory role in immune responses against parasitic infections.

Significance of multiple tumor markers measurements in conversion surgery for unresectable locally advanced pancreatic cancer.

BACKGROUND: This study aimed to evaluate the significance of multiple tumor markers (TMs) measurements in determining the indications for conversion surgery (CS) in the management of unresectable locally advanced pancreatic cancer (UR-LAPC). METHODS: A total of 103 patients with UR-LAPC, treated between 2008 and June 2021, were enrolled in this study. Three TMs, including carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA), and Duke pancreatic monoclonal antigen type 2 (DUPAN-2), were measured. RESULTS: Twenty-five patients (24%) underwent CS. The median preoperative treatment period was 9.5 months. The median survival time (MST) from the initial treatment for patients with CS was significantly longer than that for patients without surgery (34.6 vs. 18.9 months, P < 0.001). The number of elevated TMs before CS was one in five patients and two in five patients, while 15 patients had normal levels of all three TMs. Notably, the MST from the initial treatment for patients with all three preoperative normal TMs levels was favorable for 70.5 months. In contrast, patients with one or two preoperatively elevated TMs levels had a significantly worse prognosis (25.4 and 21.0 months, respectively, P < 0.001). Furthermore, the relapse-free survival of patients with three preoperative normal TMs levels was significantly longer than those with one or two elevated TMs levels (21.9 vs. 11.3 or 3.0 months, respectively, P < 0.001). Non-normal values of all TMs before CS were identified as independent poor prognostic factors. CONCLUSIONS: Simultaneous measurement and assessment of the three TMs levels may help determine the surgical indications for UR-LAPC after systemic anticancer treatment.

Combination of carbohydrate antigen 19-9 level and tumor size after neoadjuvant chemoradiation therapy may predict early recurrence of resectable pancreatic ductal adenocarcinoma.

BACKGROUND: Although the overall survival rate of patients with resectable pancreatic cancer has gradually improved, some patients relapse early and have a poor prognosis. This study aimed to identify the preoperative risk factors for early recurrence after neoadjuvant chemoradiotherapy in patients with resectable pancreatic cancer. METHODS: This study analyzed patients who underwent pancreatectomy after receiving neoadjuvant chemoradiotherapy for resectable pancreatic cancer between January 2009 and June 2021 and excluded those with borderline resectable and unresectable pancreatic cancers. Early recurrence was defined as recurrence within 6 months after surgery. RESULTS: This study included 203 patients, of whom 22 experienced early recurrence. The median survival time of patients with early recurrence was 18.3 months, which was significantly worse than that of patients with late recurrence (44.0 months, p < 0.001) or no recurrence (not reached, p < 0.001). Logistic regression analysis revealed that a carbohydrate antigen 19-9 level of >100 units/mL and a T status of ≥T2 after neoadjuvant chemoradiotherapy were independent predictive risk factors for early recurrence. The median recurrence-free survival time of patients with two risk factors was 9.7 months and significantly worse than that of those with either risk factors (20.5 months, p = 0.024) and those with no risk factor (26.2 months, p < 0.001). CONCLUSIONS: A combination of a high-level carbohydrate antigen 19-9 and a T status of ≥T2 after neoadjuvant chemoradiotherapy are predictors of early recurrence and may be helpful for selecting patients who require a stronger preoperative treatment.

Impact of the Prolonged Intermittent Pringle Maneuver on Post-Hepatectomy Liver Failure: Comparison of Open and Laparoscopic Approaches.

BACKGROUND: The influence of prolonged intermittent Pringle maneuver (IPM) on post-hepatectomy liver failure (PHLF) remains unclear. We evaluated the impact of the prolonged IPM on PHLF in patients undergoing open and laparoscopic hepatectomy. METHODS: We retrospectively included 546 patients who underwent hepatectomy using IPM. The patients were divided into open (n = 294) and laparoscopic (n = 252) groups. Odds ratios for PHLF occurrence were estimated in each group according to cumulative Pringle time (CPT). The cut-off value was set at CPT of 120 min. Risk factors for PHLF were evaluated in the open and laparoscopic groups. Additionally, we analyzed the post-operative outcomes in the open and laparoscopic groups with CPT ≥ 120 min and performed propensity score matching analysis based on PFLF-associated factors. RESULTS: In the open group, the risk of PHLF increased as CPT increased, particularly after 120 min. However, in the laparoscopic group, PHLF did not occur at less than 60 min, and the risk of PHLF was not significantly different at more than 60 min. Multivariate analysis identified CPT ≥ 120 min as an independent risk factor for PHLF in the open group (p < 0.001), but not in the laparoscopic group. Propensity score matching analysis showed that the PHLF rate was significantly lower in the laparoscopic group with CPT ≥ 120 min (p = 0.027). The post-operative transaminase levels were significantly lower in the laparoscopic group with CPT ≥ 120 min. CONCLUSIONS: Laparoscopic hepatectomy may cause less PHLF with prolonged IPM compared with open hepatectomy.

Clinical impact of sarcopenia in early-stage intrahepatic recurrent hepatocellular carcinoma: an association with impaired host immunity.

PURPOSE: This study investigated the role of sarcopenia in the long-term outcomes of patients with early-stage intrahepatic recurrent hepatocellular carcinoma (HCC). METHODS: The study included 136 patients with intrahepatic recurrent Barcelona Clinic Liver Cancer (BCLC) stage 0/A HCC following liver resection diagnosed between 2006 and 2020 and underwent surgery, radiofrequency ablation (RFA), or transcatheter arterial chemoembolization (TACE). Sarcopenia was defined based on the skeletal muscle index using computed tomography at the time of recurrence, and its association with long-term outcomes was evaluated. Tumor-infiltrating lymphocytes (CD4 + , CD8 + , and CD45RO + T cells) were assayed using immunohistochemistry on specimens obtained from repeat hepatectomies, and their association with sarcopenia was evaluated. RESULTS: The overall survival (OS) and recurrence-free survival (RFS) rates after initial recurrence of patients with sarcopenia were significantly lower than those without sarcopenia (p < 0.001 and p < 0.001, respectively). Multivariate analysis identified sarcopenia as an independent prognostic factor for RFS (p < 0.001). In patients without sarcopenia, surgery resulted in better RFS than RFA or TACE. Contrastingly, in patients with sarcopenia, the RFS was extremely poor regardless of the treatment type: surgery, RFA, or TACE (median RFS, 11.7, 12.7, and 10.1 months). Significantly low levels of tumor-infiltrating CD4 + , CD8 + , and CD45RO + lymphocytes were observed in patients with sarcopenia (p = 0.001, p = 0.001, and p = 0.001, respectively). CONCLUSIONS: This study suggests that patients with sarcopenia have poor RFS regardless of the treatment type for early-stage intrahepatic recurrent HCC. Impaired host immunity might be one of the underlying mechanisms.

Transcriptomic Profiling Identifies an Exosomal microRNA Signature for Predicting Recurrence Following Surgery in Patients With Pancreatic Ductal Adenocarcinoma.

OBJECTIVE: We performed genome-wide expression profiling to develop an exosomal miRNA panel for predicting recurrence following surgery in patients with PDAC. SUMMARY OF BACKGROUND DATA: Pretreatment risk stratification is essential for offering individualized treatments to patients with PDAC, but predicting recurrence following surgery remains clinically challenging. METHODS: We analyzed 210 plasma and serum specimens from 4 cohorts of PDAC patients. Using a discovery cohort (n = 25), we performed genome-wide sequencing to identify candidate exosomal miRNAs (exo-miRNAs). Subsequently, we trained and validated the predictive performance of the exo-miRNAs in two clinical cohorts (training cohort: n = 82, validation cohort: n = 57) without neoadjuvant therapy (NAT), followed by a post-NAT clinical cohort (n = 46) as additional validation. RESULTS: We performed exo-miRNA expression profiling in plasma specimens obtained before any treatment in a discovery cohort. Subsequently we optimized and trained a 6-exo-miRNA risk-prediction model, which robustly discriminated patients with recurrence [area under the curve (AUC): 0.81, 95% confidence interval (CI): 0.70-0.89] and relapse-free survival (RFS, P < 0.01) in the training cohort. The identified exo-miRNA panel was successfully validated in an independent validation cohort (AUC: 0.78, 95% CI: 0.65- 0.88, RFS: P < 0.01), where it exhibited comparable performance in the post-NAT cohort (AUC: 0.72, 95% CI: 0.57-0.85, RFS: P < 0.01) and emerged as an independent predictor for RFS (hazard ratio: 2.84, 95% CI: 1.30-6.20). CONCLUSIONS: We identified a novel, noninvasive exo-miRNA signature that robustly predicts recurrence following surgery in patients with PDAC; highlighting its potential clinical impact for optimized patient selection and improved individualized treatment strategies.

A gene expression signature for predicting response to neoadjuvant chemoradiotherapy in pancreatic ductal adenocarcinoma.

In patients with pancreatic ductal adenocarcinoma (PDAC), optimal treatment selection, including multimodality regimens such as neoadjuvant chemoradiotherapy (NACRT), can be clinically transformative. Unfortunately, currently no predictive biomarkers are available that can guide the use of NACRT in PDAC patients. Accordingly, herein we developed a novel gene signature that can preoperatively predict NACRT-sensitivity in PDAC patients. Herein, we evaluated the performance of a 10-gene panel in 749 PDAC cases, which included two public datasets (The Cancer Genome Atlas and International Cancer Genome Consortium; n = 276), and three clinical specimen cohorts (n = 417), and a pre-NACRT endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy cohort (n = 56). The potential predictive performance of this signature was evaluated and compared to CA-19-9 levels and key clinicopathological factors. We first evaluated the prognostic potential of a 10-gene panel which significantly predicted overall survival in both public datasets (P < .01, P < .01), and two in-house patient cohorts (P < .01, P = .04). In the pre-NACRT EUS-FNA cohort, we established a radio-sensitivity gene panel (RSGP) which yielded highly robust (area under the curve [AUC] = 0.91; 95% CI: 0.81-0.97) for predicting response to gemcitabine-based NACRT. Multivariate logistic regression analysis revealed that RSGP was an independent predictor for response to NACRT (OR = 2.70; 95% CI: 1.25-5.85), and this response-prediction was even more robust when CA-19-9 levels were included into the model. In conclusion, we have validated and developed a novel gene signature that is highly robust in predicting response to NACRT, even in preoperative settings, highlighting its clinical significance for optimizing and personalizing treatment strategies in PDAC patients.

A MicroRNA Signature Identifies Pancreatic Ductal Adenocarcinoma Patients at Risk for Lymph Node Metastases.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinomas (PDACs) frequently metastasize to the lymph nodes; strategies are needed to identify patients at highest risk for lymph node metastases. We performed genome-wide expression profile analyses of PDAC specimens, collected during surgery or endoscopic ultrasound-guided fine-need aspiration (EUS-FNA), to identify a microRNA (miRNA) signature associated with metastasis to lymph nodes. METHODS: For biomarker discovery, we analyzed miRNA expression profiles of primary pancreatic tumors from 3 public data sets (The Cancer Genome Atlas, GSE24279, and GSE32688). We then analyzed 157 PDAC specimens (83 from patients with lymph node metastases and 74 without) from Japan, collected from 2001 through 2017, for the training cohort and 107 PDAC specimens (63 from patients with lymph node metastases and 44 without) from a different medical center in Japan, from 2002 through 2016, for the validation cohort. We also analyzed samples collected by EUS-FNA before surgery from 47 patients (22 patients with lymph node metastases and 25 without; 17 for the training cohort and 30 from the validation cohort) and 62 specimens before any treatment from patients who received neoadjuvant chemotherapy (9 patients with lymph node metastasis and 53 without) for additional validation. Multivariate logistic regression analyses were used to evaluate the statistical differences in miRNA expression between patients with vs without metastases. RESULTS: We identified an miRNA expression pattern associated with diagnosis of PDAC metastasis to lymph nodes. Using logistic regression analysis, we optimized and trained a 6-miRNA risk prediction model for the training cohort; this model discriminated patients with vs without lymph node metastases with an area under the curve (AUC) of 0.84 (95% confidence interval [CI], 0.77-0.89). In the validation cohort, the model identified patients with vs without lymph node metastases with an AUC of 0.73 (95% CI, 0.64-0.81). In EUS-FNA biopsy samples, the model identified patients with vs without lymph node metastases with an AUC of 0.78 (95% CI, 0.63-0.89). The miRNA expression pattern was an independent predictor of PDAC metastasis to lymph nodes in the validation cohort (odds ratio, 17.05; 95% CI, 2.43-119.57) and in the EUS-FNA cohort (95% CI, 0.65-0.87). CONCLUSIONS: Using data and tumor samples from 3 independent cohorts, we identified an miRNA signature that identifies patients at risk for PDAC metastasis to lymph nodes. The signature has similar levels of accuracy in the analysis of resected tumor specimens and EUS-FNA biopsy specimens. This model might be used to select treatment and management strategies for patients with PDAC.

Clinical Importance of CD200 Expression in Colorectal Liver Metastasis.

BACKGROUND: Approximately 30% of patients diagnosed with colorectal cancer (CRC) develop liver metastases. We evaluated the role of CD200, a potent immunosuppressive molecule, in colorectal liver metastases (CRLM). METHODS: We examined 110 patients who underwent curative liver resection for CRLM at our institution between 2000 and 2016. Based on the results of immunohistochemical analysis, the patients were divided into high-CD200 (n = 47) and low-CD200 (n = 63) expression groups. The relationships between CD200 expression and various clinicopathological outcomes were investigated. RESULTS: The overall survival (OS) of patients in the high-CD200 group was significantly worse than that in the low-CD200 group (p = 0.009). Multivariate analysis showed that the independent prognostic factors in CRLM were maximum tumor size > 30 mm (p = 0.002), preoperative carcinoembryonic antigen level > 20 ng/mL (p < 0.001), primary CRC N2-3 (p = 0.049), and high-CD200 expression (p = 0.004). Furthermore, CD4+, CD8+, and CD45RO+ tumor-infiltrating lymphocytes in CRLM were significantly higher in the low-CD200 group than in the high-CD200 group (p = 0.005, p = 0.001, and p < 0.001, respectively). In addition, patients who had received preoperative chemotherapy had higher CD200 expression than those who had not received preoperative chemotherapy, and OS was significantly worse in patients in the high-CD200 group who had received preoperative chemotherapy. CONCLUSIONS: CD200 expression was an independent prognostic factor in CRLM. CD200 may play a critical role in tumor immunity in CRLM, and can therefore be used as a potential therapeutic target in CRLM.

Clinical relevance of CD70 expression in resected pancreatic cancer: Prognostic value and therapeutic potential.

BACKGROUND: Aberrant expression of CD70 in several malignancies is potentially associated with poor patient prognosis and could serve as a therapeutic target. However, the clinical relevance of CD70 expression in pancreatic cancer has not been thoroughly explored. METHODS: We evaluated CD70 expression in 166 surgical specimens obtained from human patients with pancreatic cancer. We analyzed the function of CD70 in proliferation and migration using pancreatic cancer cell lines with silenced CD70 expression. RESULTS: CD70 expression was positively stained in 42 patients (25%). In the whole cohort, high CD70 expression was not associated with overall survival (OS: 33.1 vs. 40.8 months, P = 0.256), although it was significantly associated with inferior OS in a population of patients that completed adjuvant chemotherapy (OS: 45.4 vs. 63.8 months, P = 0.027). Moreover, the incidence of hematogenous metastasis was significantly higher in patients with high CD70 expression than in those with low CD70 expression (P = 0.020). This finding was also statistically significant in multivariate analyses (P = 0.001). In vitro experiments demonstrated that CD70 expression contributed to cancer cell proliferation independently of gemcitabine treatment as well as cell migration. Furthermore, real-time polymerase chain reaction analysis of frozen surgical tissues showed a correlation between the expression of CD70 and mesenchymal markers. CONCLUSIONS: CD70 expression in pancreatic cancer might be involved in hematogenous metastasis. Furthermore, our results imply that CD70 overexpression can serve as a novel prognostic factor and a potential therapeutic target in patients who have completed adjuvant chemotherapy.

Correction to: Novel method to estimate the appropriate dosing interval for activated charcoal to avoid interaction with other drugs.

Figure 3 image was inadvertently removed from the original article. The original article has been corrected.

Novel method to estimate the appropriate dosing interval for activated charcoal to avoid interaction with other drugs.

PURPOSE: Activated charcoal is known to adsorb a variety of drugs concomitantly administered and reduce their intestinal absorption, and separating the dosing is considered a practical approach to avoid this drug interaction. The aim of the present study was to develop and validate a simple method to estimate the sufficient dosing interval to avoid drug interaction using the pharmacokinetic profile of the subject drugs administered alone and the amplitude of interaction upon simultaneous administration with activated charcoal. METHODS: For each subject drug, the pharmacokinetic profile and the amplitude of interaction, as assessed by AUCR (the ratio of area under the plasma concentration-time curve (AUC) in the presence of activated charcoal to that in its absence), were collected from previous reports. The AUCR value was estimated based on the compartment model under the assumption that the subject drug in the first gastrointestinal compartment is immediately adsorbed to a certain extent upon the administration of activated charcoal. The estimated AUCR (AUCRe) for each drug with certain dosing interval was compared with the respective AUCR value reported previously (AUCRobs). RESULTS: Among twenty concentration profiles for 14 subject drugs obtained from previous reports, 15 AUCRe values fell in the range of 80-120% of the respective AUCRobs values. CONCLUSION: The developed method enabled estimation of the amplitude of DDI by activated charcoal administered in a certain dosing interval, whereas overestimation of AUCRe was observed for drugs that undergo extensive enterohepatic circulation.

cyAbrB Transcriptional Regulators as Safety Devices To Inhibit Heterocyst Differentiation in Anabaena sp. Strain PCC 7120.

Cyanobacteria are monophyletic organisms that perform oxygenic photosynthesis. While they exhibit great diversity, they have a common set of genes. However, the essentiality of them for viability has hampered the elucidation of their functions. One example of these genes is cyabrB1 (also known as calA in Anabaena sp. strain PCC 7120), encoding a transcriptional regulator. In the present study, we investigated the function of calA/cyabrB1 in the heterocyst-forming cyanobacterium Anabaena sp. PCC 7120 through CRISPR interference, a method that we recently utilized for the photosynthetic production of a useful chemical in this strain. Conditional knockdown of calA/cyabrB1 in the presence of nitrate resulted in the formation of heterocysts. Two genes, hetP and hepA, which are required for heterocyst formation, were upregulated by calA/cyabrB1 knockdown in the presence of combined nitrogen sources. These genes are known to be induced by HetR, a master regulator of heterocyst formation. hetR was not induced by calA/cyabrB1 knockdown. hetP and hepA were repressed by direct binding of CalA/cyAbrB1 to their promoter regions in a HetR-independent manner. In addition, the overexpression of calA/cyabrB1 abolished heterocyst formation upon nitrogen depletion. Also, knockout of calB/cyabrB2 (a paralogue gene of calA/cyabrB1), in addition to knockdown of calA/cyabrB1, enhanced heterocyst formation in the presence of nitrate, suggesting functional redundancy of cyAbrB proteins. We propose that a balance between amounts of HetR and CalA/cyAbrB1 is a key factor influencing heterocyst differentiation during nitrogen stepdown. We concluded that cyAbrB proteins are essential safety devices that inhibit heterocyst differentiation.IMPORTANCE Spore formation in Bacillus subtilis and Streptomyces has been extensively studied as models of prokaryotic nonterminal cell differentiation. In these organisms, many cells/hyphae differentiate simultaneously, which is governed by a network in which one regulator stands at the top. Differentiation of heterocysts in Anabaena sp. strain PCC 7120 is unique because it is terminal, and only 5 to 10% of vegetative cells differentiate into heterocysts. In this study, we identified CalA/cyAbrB1 as a repressor of two genes that are essential for heterocyst formation independently of HetR, a master activator for heterocyst differentiation. This finding is reasonable for unique cell differentiation of Anabaena because CalA/cyAbrB1 could suppress heterocyst differentiation tightly in vegetative cells, while only cells in which HetR is overexpressed could differentiate into heterocysts.

Phase II Study of the Triple Combination Chemotherapy of SOXIRI (S-1/Oxaliplatin/Irinotecan) in Patients with Unresectable Pancreatic Ductal Adenocarcinoma.

LESSONS LEARNED: The triple combination chemotherapy of SOXIRI (S-1/oxaliplatin/irinotecan) in patients with unresectable pancreatic ductal adenocarcinoma was an effective treatment that appeared to be better tolerated than the widely used FOLFIRINOX regimen.SOXIRI regimen may provide an alternative approach for advanced pancreatic cancer. BACKGROUND: In our previous phase I study, we determined the recommended dose of a biweekly S-1, oxaliplatin, and irinotecan (SOXIRI) regimen in patients with unresectable pancreatic ductal adenocarcinoma (PDAC). This phase II study was conducted to assess the safety and clinical efficacy in patients with unresectable PDAC. METHODS: Patients with previously untreated metastatic and locally advanced PDAC were enrolled. The primary endpoint was response rate (RR). Secondary endpoints were adverse events (AEs), progression-free survival (PFS), and overall survival (OS). Patients received 80 mg/m2 of S-1 twice a day for 2 weeks in alternate-day administration, 150 mg/m2 of irinotecan on day 1, and 85 mg/m2 of oxaliplatin on day 1 of a 2-week cycle. RESULTS: Thirty-five enrolled patients received a median of six (range: 2-15) treatment cycles. The RR was 22.8% (95% confidence interval [CI]: 10.4-40.1); median OS, 17.7 months (95% CI: 9.8-22.0); and median PFS, 7.4 months (95% CI: 4.2-8.4). Furthermore, the median OS in patients with distant metastasis was 10.1 months, whereas that in patients with locally advanced PDAC was 22.6 months. Major grade 3 or 4 toxicity included neutropenia (54%), anemia (17%), febrile neutropenia (11%), anorexia (9%), diarrhea (9%), and nausea (9%). There were no treatment-related deaths. CONCLUSION: SOXIRI is considered a promising and well-tolerated regimen in patients with unresectable PDAC.

Significance of the inflammation-based prognostic score in recurrent pancreatic cancer.

BACKGROUND: Although the prognosis of recurrent pancreatic cancer (RPC) is improving with the appearance of new anticancer drugs, prognostic indicators for RPC are still poorly understood. The aim of this study was to evaluate significance of the inflammation-based prognostic score, including modified Glasgow Prognostic Score (mGPS), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and Prognostic Nutritional Index (PNI), in patients with RPC. METHODS: This study reviewed 263 patients of pancreatic ductal adenocarcinoma at our institution between 2006 and 2015. A receiver operating characteristics curve analysis was performed to determine the cut-off values. The prognostic significance of the inflammation-based prognostic scores were evaluated by a multivariate analysis. RESULTS: 172 patients (65.4%) who had recurrence was included in this study. The optimal PNI for predicting 1-year survival after recurrence was 40 with higher area under receiver operating characteristics curve value (0.704) in comparison with other inflammation-based prognostic scores. A univariate and multivariate analysis revealed that liver metastasis (P < 0.001) and PNI < 40 (P < 0.001) were independently associated with the survival time after recurrence. When each of the two predictors was counted as one point and the points were calculated for all cases, a good stratified survival curve was obtained, showing the shorter survival in the higher points: median survival times of 2, 1, and 0 points were 4.3, 11.1, and 21.2 months, respectively (P < 0.001). CONCLUSIONS: Inflammation-based prognostic scores, especially PNI is useful clinical biomarker for predicting the survival time after recurrence in patients with pancreatic adenocarcinoma.

Risk Factors for Late-Onset Gastrointestinal Hemorrhage After Pancreatoduodenectomy for Pancreatic Cancer.

BACKGROUND: Late-onset gastrointestinal hemorrhage after pancreatoduodenectomy (PD) occasionally occurs repeatedly or leads to a serious condition. This retrospective study aimed to clarify its frequency and pathogenesis. METHODS: A total of 147 consecutive patients who underwent PD for pancreatic cancer between 2006 and 2014 were evaluated. Patients were divided into two groups according to the occurrence of late-onset gastrointestinal hemorrhage on postoperative day 100 or later. Furthermore, recurrence and portal vein (PV) hemodynamics were thoroughly reevaluated by computed tomography. RESULTS: Eleven patients experienced late-onset gastrointestinal hemorrhage. The bleeding sites were gastrojejunostomy in four patients, choledochojejunostomy in two, transverse colic marginal vein in one, and unknown in four. The median occurrence time of late-onset gastrointestinal hemorrhage was 13.3 months after PD. PV occlusion (63.6 vs. 8.9%; p < 0.001), no patency of PV-splenic vein (SPV) confluence (54.5 vs. 12.7%; p = 0.002), and SPV ligation (36.4 vs. 9.6%; p = 0.025) were found to be significant risk factors for late-onset gastrointestinal hemorrhage. Among 11 patients who experienced late-onset gastrointestinal hemorrhage, 7 had PV occlusion and 6 had local recurrence. CONCLUSIONS: Our data suggested for the first time that both oncologic and non-oncologic factors might contribute to late-onset gastrointestinal hemorrhage after PD for pancreatic cancer. Furthermore, PV occlusion, no PV-SPV patency, and SPV ligation were found to be significant risk factors for late-onset gastrointestinal hemorrhage. Therefore, to prevent late-onset gastrointestinal hemorrhage, we must consider various approaches to maintain the patency of the PV and SPV.