Gene expression classification of colon cancer into molecular subtypes: characterization, validation, and prognostic value

BACKGROUND

Colon cancer (CC) pathological staging fails to accurately predict recurrence, and to date, no gene expression signature has proven reliable for prognosis stratification in clinical practice, perhaps because CC is a heterogeneous disease. The aim of this study was to establish a comprehensive molecular classification of CC based on mRNA expression profile analyses.

METHODS AND FINDINGS

Fresh-frozen primary tumor samples from a large multicenter cohort of 750 patients with stage I to IV CC who underwent surgery between 1987 and 2007 in seven centers were characterized for common DNA alterations, including BRAF, KRAS, and TP53 mutations, CpG island methylator phenotype, mismatch repair status, and chromosomal instability status, and were screened with whole genome and transcriptome arrays. 566 samples fulfilled RNA quality requirements. Unsupervised consensus hierarchical clustering applied to gene expression data from a discovery subset of 443 CC samples identified six molecular subtypes. These subtypes were associated with distinct clinicopathological characteristics, molecular alterations, specific enrichments of supervised gene expression signatures (stem cell phenotype-like, normal-like, serrated CC phenotype-like), and deregulated signaling pathways. Based on their main biological characteristics, we distinguished a deficient mismatch repair subtype, a KRAS mutant subtype, a cancer stem cell subtype, and three chromosomal instability subtypes, including one associated with down-regulated immune pathways, one with up-regulation of the Wnt pathway, and one displaying a normal-like gene expression profile. The classification was validated in the remaining 123 samples plus an independent set of 1,058 CC samples, including eight public datasets. Furthermore, prognosis was analyzed in the subset of stage II-III CC samples. The subtypes C4 and C6, but not the subtypes C1, C2, C3, and C5, were independently associated with shorter relapse-free survival, even after adjusting for age, sex, stage, and the emerging prognostic classifier Oncotype DX Colon Cancer Assay recurrence score (hazard ratio 1.5, 95% CI 1.1-2.1, p = 0.0097). However, a limitation of this study is that information on tumor grade and number of nodes examined was not available.

CONCLUSIONS

We describe the first, to our knowledge, robust transcriptome-based classification of CC that improves the current disease stratification based on clinicopathological variables and common DNA markers. The biological relevance of these subtypes is illustrated by significant differences in prognosis. This analysis provides possibilities for improving prognostic models and therapeutic strategies. In conclusion, we report a new classification of CC into six molecular subtypes that arise through distinct biological pathways.

Effect of Interval (7 or 11 weeks) Between Neoadjuvant Radiochemotherapy and Surgery on Complete Pathologic Response in Rectal Cancer: A Multicenter, Randomized, Controlled Trial (GRECCAR-6)

Purpose A pathologic complete response (pCR; ypT0N0) of a rectal tumor after neoadjuvant radiochemotherapy (RCT) is associated with an excellent prognosis. Several retrospective studies have investigated the effect of increasing the delay after RCT. The aim of this study was to evaluate the effect of increasing the interval between the end of RCT and surgery on the pCR rate. Methods GRECCAR6 was a phase III, multicenter, randomized, open-label, parallel-group controlled trial. Patients with cT3/T4 or Tx N+ tumors of the mid or lower rectum who had received RCT (45 to 50 Gy with fluorouracil or capecitabine) were included. Patients were randomly included in the 7-week or the 11-week (11w) group. Primary end point was the pCR rate defined as a ypT0N0 specimen (NCT01648894). Results A total of 265 patients from 24 centers were enrolled between October 2012 and February 2015. The majority of the tumors were cT3 (82%). After RCT, surgery was not performed in nine patients (3.4%) because of the occurrence of distant metastasis (n = 5) or other reasons. Two patients underwent local resection of the tumor scar. A total of 47 (18.6%) specimens were classified as ypT0 (four had invaded lymph nodes [8.5%]). The primary end point (ypT0N0) was not different (7 weeks: 20 of 133, 15.0% v 11w: 23 of 132, 17.4%; P = .5983). Morbidity was significantly increased in the 11w group (44.5% v 32%; P = .0404) as a result of increased medical complications (32.8% v 19.2%; P = .0137). The 11w group had a worse quality of mesorectal resection (complete mesorectum [I] 78.7% v 90%; P = .0156). Conclusion Waiting 11 weeks after RCT did not increase the rate of pCR after surgical resection. A longer waiting period may be associated with higher morbidity and more difficult surgical resection.

Risk factors for mortality and intra-abdominal complications after pancreatoduodenectomy: multivariate analysis in 300 patients

BACKGROUND

Studies of risk factors after pancreatoduodenectomy are few: some concern restricted populations and others are based on administrative data.

METHODS

Multicenter clinical data were collected for 300 patients undergoing pancreatoduodenectomy to determine (by univariate and multivariate analysis) preoperative and intraoperative risk factors for mortality and intra-abdominal complications (IACs), including pancreatic fistula. Fourteen factors including the center and volume effect were analyzed.

RESULTS

In univariate analysis, mortality was increased with age 70 years or more, extended resection(s), and volume and center effects. IACs occurred more often with main pancreatic duct diameter of 3 mm or less, normal parenchyma texture, extended resection(s), and the center effect. Pancreatic fistula was more frequent with main pancreatic duct diameter of 3 mm or less, normal parenchyma texture, and the center effect. In multivariate analysis, independent risk factor(s) for mortality were age greater than 70 years (odds ratio [OR], 3; 95% confidence interval [CI], 1.3-8) and extended resection (OR, 5; 95% CI, 1.2-22), risk factors for IACs were extended resection (OR, 5; 95% CI, 1.2-22) and main pancreatic duct diameter of 3 mm or less (OR, 2; 95% CI, 1.1-3), and the risk factor for pancreatic fistula was main pancreatic duct diameter of 3 mm or less (OR, 2.5; 95% CI, 1.2-4.6).

CONCLUSIONS

Age more than 70 years, extended resections, and main pancreatic duct diameter less than 3 mm are independent risk factors that should be considered in indications for and techniques of pancreatoduodenectomy.

Expression of a mutant HSP110 sensitizes colorectal cancer cells to chemotherapy and improves disease prognosis

Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorouracil, which are routinely prescribed in the adjuvant treatment of people with CRC. The survival and response to chemotherapy of subjects with MSI CRCs was associated with the tumor expression level of HSP110ΔE9. HSP110 may thus constitute a major determinant for both prognosis and treatment response in CRC.

Sporadic early-onset colorectal cancer is a specific sub-type of cancer: a morphological, molecular and genetics study

Sporadic early onset colorectal carcinoma (EOCRC) which has by definition no identified hereditary predisposition is a growing problem that remains poorly understood. Molecular analysis could improve identification of distinct sub-types of colorectal cancers (CRC) with therapeutic implications and thus can help establish that sporadic EOCRC is a distinct entity. From 954 patients resected for CRC at our institution, 98 patients were selected. Patients aged 45–60 years were excluded to help define “young” and “old” groups. Thirty-nine cases of sporadic EOCRC (patients≤45 years with microsatellite stable tumors) were compared to both microsatellite stable tumors from older patients (36 cases, patients>60 years) and to groups of patients with microsatellite instability. Each group was tested for TP53, KRAS, BRAF, PIK3CA mutations and the presence of a methylator phenotype. Gene expression profiles were also used for pathway analysis. Compared to microsatellite stable CRC from old patients, sporadic EOCRC were characterized by distal location, frequent synchronous metastases and infrequent synchronous adenomas but did not have specific morphological characteristics. A familial history of CRC was more common in sporadic EOCRC patients despite a lack of identified hereditary conditions (p = 0.013). Genetic studies also showed the absence of BRAF mutations (p = 0.022) and the methylator phenotype (p = 0.005) in sporadic EOCRC compared to older patients. Gene expression analysis implicated key pathways such as Wnt/beta catenin, MAP Kinase, growth factor signaling (EGFR, HGF, PDGF) and the TNFR1 pathway in sporadic EOCRC. Wnt/beta catenin signaling activation was confirmed by aberrant nuclear beta catenin immunostaining (p = 0.01). This study strongly suggests that sporadic EOCRC is a distinct clinico-molecular entity presenting as a distal and aggressive disease associated with chromosome instability. Furthermore, several signaling pathways including the TNFR1 pathway have been identified as potential biomarkers for both the diagnosis and treatment of this disease.

UGT1A1 polymorphism can predict hematologic toxicity in patients treated with irinotecan

PURPOSE

Irinotecan (CPT-11) is approved in metastatic colorectal cancer treatment and can cause severe toxicity. The main purpose of our study was to assess the role of different polymorphisms on the occurrence of hematologic toxicities and disease-free survival in high-risk stage III colon cancer patients receiving 5-fluorouracil (5FU) and CPT-11 adjuvant chemotherapy regimen in a prospective randomized trial.

EXPERIMENTAL DESIGN

Four hundred patients were randomized in a phase III trial comparing LV5FU2 to LV5FU2 + CPT-11. DNA from 184 patients was extracted and genotyped to detect nucleotide polymorphism: 3435C>T for ABCB1, 6986A>G for CYP3A5, UGT1A1*28 and -3156G>A for UGT1A1.

RESULTS

Genotype frequencies were similar in both treatment arms. In the test arm, no significant difference was observed in toxicity or disease-free survival for ABCB1 and CYP3A5 polymorphisms. UGT1A1*28 homozygous patients showed more frequent severe hematologic toxicity (50%) than UGT1A1*1 homozygous patients (16.2%), P = 0.06. Moreover, patients homozygous for the mutant allele of -3156G>A UGT1A1 polymorphism showed more frequent severe hematologic toxicity (50%) than patients homozygous for wild-type allele (12.5%), P = 0.01. This toxicity occurred significantly earlier in homozygous mutant than wild-type homozygous patients (P = 0.043). In a Cox model, the hazard ratio for severe hematologic toxicity is significantly higher for patients with the A/A compared with the G/G genotype [hazard ratio, 8.4; 95% confidence interval, 1.9-37.2; P = 0.005].

CONCLUSIONS

This study supports the clinical utility of identification of UGT1A1 promoter polymorphisms before LV5FU2 + CPT-11 treatment to predict early hematologic toxicity. The -3156G>A polymorphism seems to be a better predictor than the UGT1A1 (TA)(6)TAA>(TA)(7)TAA polymorphism.

Epithelial expression and function of trypsin-3 in irritable bowel syndrome

OBJECTIVES

Proteases are key mediators of pain and altered enteric neuronal signalling, although the types and sources of these important intestinal mediators are unknown. We hypothesised that intestinal epithelium is a major source of trypsin-like activity in patients with IBS and this activity signals to primary afferent and enteric nerves and induces visceral hypersensitivity.

DESIGN

Trypsin-like activity was determined in tissues from patients with IBS and in supernatants of Caco-2 cells stimulated or not. These supernatants were also applied to cultures of primary afferents. mRNA isoforms of trypsin (PRSS1, 2 and 3) were detected by reverse transcription-PCR, and trypsin-3 protein expression was studied by western blot analysis and immunohistochemistry. Electrophysiological recordings and Ca²⁺ imaging in response to trypsin-3 were performed in mouse primary afferent and in human submucosal neurons, respectively. Visceromotor response to colorectal distension was recorded in mice administered intracolonically with trypsin-3.

RESULTS

We showed that stimulated intestinal epithelial cells released trypsin-like activity specifically from the basolateral side. This activity was able to activate sensory neurons. In colons of patients with IBS, increased trypsin-like activity was associated with the epithelium. We identified that trypsin-3 was the only form of trypsin upregulated in stimulated intestinal epithelial cells and in tissues from patients with IBS. Trypsin-3 was able to signal to human submucosal enteric neurons and mouse sensory neurons, and to induce visceral hypersensitivity in vivo, all by a protease-activated receptor-2-dependent mechanism.

CONCLUSIONS

In IBS, the intestinal epithelium produces and releases the active protease trypsin-3, which is able to signal to enteric neurons and to induce visceral hypersensitivity.

Meta-analysis: evaluation of adjuvant therapy after curative liver resection for hepatocellular carcinoma

AIM

To evaluate adjuvant modalities after curative resection for hepatocellular carcinoma using a meta-analysis of randomized and non-randomized controlled trials.

METHODS

In a first step, a meta-analysis of randomized controlled trials was carried out. Sensitivity analyses after inclusion of non-randomized controlled trials were performed. Four therapeutic modalities were evaluated: pre-operative transarterial chemotherapy, post-operative transarterial chemotherapy, systemic chemotherapy and a combination of systemic and transarterial chemotherapy.

RESULTS

Only post-operative transarterial chemotherapy improved survival significantly at 2 years [difference, 22.8%; confidence interval (CI), 8.6-36.9%; P = 0.002] and 3 years (difference, 27.6%; CI, 8.2-47.1%; P = 0.005), and decreased the probability of no recurrence at 1 year (difference, 28.8%; CI, 16.7-40.8%; P < 0.001), 2 years (difference, 27.6%; CI, 8.2-47.1%; P = 0.005) and 3 years (difference, 28%; CI, 8.2-47.9%; P = 0.006). In a sensitivity analysis after inclusion of non-randomized controlled trials, post-operative transarterial chemotherapy still improved survival at 1 year (difference, 9.6%; CI, 0.8-18.3%; P = 0.03), 2 years (difference, 13.5%; CI, 0.9-26%, P = 0.04) and 3 years (difference, 18%; CI, 7-28.9%; P < 0.001), and decreased the probability of no recurrence at 1 year (difference, 20.3%; CI, 7.7-33%; P = 0.002), 2 years (difference, 35%; CI, 21.4-46.3%; P < 0.001) and 3 years (difference, 34.5%; CI, 18.7-50.3%; P < 0.001).

CONCLUSION

Post-operative transarterial chemotherapy improved survival and decreased the cumulative probability of no recurrence. New randomized controlled trials evaluating this modality are required.

Characterization of Human Colon Organoids From Inflammatory Bowel Disease Patients

Inflammatory Bowel Diseases (IBD) are chronic inflammatory disorders, where epithelial defects drive, at least in part, some of the pathology. We reconstituted human intestinal epithelial organ, by using three-dimension culture of human colon organoids. Our aim was to characterize morphological and functional phenotypes of control (non-IBD) organoids, compared to inflamed organoids from IBD patients. The results generated describe the epithelial defects associated with IBD in primary organoid cultures, and evaluate the use of this model for pharmacological testing of anti-inflammatory approaches. Human colonic tissues were obtained from either surgical resections or biopsies, all harvested in non-inflammatory zones. Crypts were isolated from controls (non-IBD) and IBD patients and were cultured up to 12-days. Morphological (size, budding formation, polarization, luminal content), cell composition (proliferation, differentiation, immaturity markers expression), and functional (chemokine and tight junction protein expression) parameters were measured by immunohistochemistry, RT-qPCR or western-blot. The effects of inflammatory cocktail or anti-inflammatory treatments were studied in controls and IBD organoid cultures respectively. Organoid cultures from controls or IBD patients had the same cell composition after 10 to 12-days of culture, but IBD organoid cultures showed an inflammatory phenotype with decreased size and budding capacity, increased cell death, luminal debris, and inverted polarization. Tight junction proteins were also significantly decreased in IBD organoid cultures. Inflammatory cytokine cocktail reproduced this inflammatory phenotype in non-IBD organoids. Clinically used treatments (5-ASA, glucocorticoids, anti-TNF) reduced some, but not all parameters. Inflammatory phenotype is associated with IBD epithelium, and can be studied in organoid cultures. This model constitutes a reliable human pre-clinical model to investigate new strategies targeting epithelial repair.

Oncological outcome of ultra-low coloanal anastomosis with and without intersphincteric resection for low rectal adenocarcinoma

BACKGROUND

The value of ultra-low coloanal anastomosis (CAA) for rectal cancer is dependent on the oncological and functional results. The aim of this comparative study was to evaluate the long-term oncological outcome of CAA with or without intersphincteric resection (ISR) for low-lying rectal tumours.

METHODS

The study population comprised consecutive patients with low rectal cancer who underwent CAA in a single institution between 1977 and 2004. Patients were divided into two groups according to whether or not a partial ISR had been performed. Cox multivariate models were used for survival analysis.

RESULTS

Some 278 patients underwent CAA with curative intent; 173 had ISR and 105 had CAA without ISR. Mean follow-up was 66.8 months. The 5-year actuarial rate for local recurrence, regardless of tumour stage, was 10.6 per cent in the ISR group versus 6.7 per cent for CAA alone (P = 0.405), and the 5-year actuarial overall survival rate was 86.1 and 80.0 per cent respectively (P = 0.318). Cox multivariable analysis revealed that resection of the anal canal was not a prognostic factor for local or metastatic recurrence.

CONCLUSION

Sphincter-preserving surgery appears to be oncologically adequate for very low-lying rectal tumours.

Management of rectal cancer: the 2016 French guidelines

AIM

Rectal cancer is a malignant disease requiring multidisciplinary management. In view of the increasing number of studies published over the past decade, a comprehensive update is required to draw recommendations for clinical practice mandated by the French Research Group of Rectal Cancer Surgery and the French National Coloproctology Society.

METHOD

Seven questions summarizing the treatment of rectal cancer were selected. A search for evidence in the literature from January 2004 to December 2015 was performed. A drafting committee and a large group of expert reviewers contributed to validate the statements.

RESULTS

Recommendations include the indications for neoadjuvant therapy, the quality criteria for surgical resection, the management of postoperative disordered function, the role of local excision in early rectal cancer, the place of conservative strategies after neoadjuvant treatment, the management of synchronous liver metastases and the indications for adjuvant therapy. A level of evidence was assigned to each statement.

CONCLUSION

The current clinical practice guidelines are useful for the treatment of rectal cancer. Some statements require a higher level of evidence due to a lack of studies.

The effect of abdominal ventral rectopexy on faecal incontinence and constipation in patients with internal intra-anal rectal intussusception

AIM

Optimal treatment of anal incontinence in a patients with a normal anal sphincter is controversial, as is the role of intra-anal rectal intussusception in anal incontinence. We evaluated the results of abdominal ventral rectopexy on anal continence in such patients.

METHOD

Forty consecutive patients with incontinence and intra-anal rectal intussusception without a sphincter defect were treated by abdominal ventral mesh rectopexy without sigmoidectomy. The Cleveland Clinic Incontinence Score (CCIS), patient satisfaction and constipation before and after surgery and recurrence were recorded.

RESULTS

The mean CCI scores were 13.2 (=/-4.25) preoperatively and 3 (±3.44) postoperatively (P<0.0001). Patient assessment was reported as 'cured' in 26 (65%), 'improved' in 13 (32.5%) and 'unchanged' in one (2.5%) patient. Constipation was induced in two (5%) patients and was cured in 13 of 20 (65%) patients who were constipated before surgery. One case of recurrent prolapse occurred after a mean follow-up of 38 months.

CONCLUSION

Intra-anal rectal intussusception may be associated with anal incontinence. For these patients, abdominal ventral mesh rectopexy appears to be an adequate treatment.

Is Crohn's creeping fat an adipose tissue?

BACKGROUND

In human pathology, the "creeping fat" (CF) of the mesentery is unique to Crohn's disease (CD). CF is usually referred to as an ectopic extension of mesenteric adipose tissue (MAT). However, since no animal model developing CF has ever been established, very little is known about this type of fat-depot expansion and its role in the development of the disease.

METHODS

We developed and standardized an experimental protocol in mice that reproducibly induces CF development when a severe colonic inflammation is obtained by intracolonic instillation of DNBS.

RESULTS

Macro-microscopic observations revealed a fatty appearance of CF. Yet when compared to MAT from the same animals, CF contains very little triglycerides, few adipocytes, and we observed a very low expression and protein levels of both adipose markers (hormone-sensitive lipase, perilipin) and adipocytokines (leptin, adiponectin). The decreased expression of perilipin in CF was also observed by immunohistochemistry. Conversely, the expression of proinflammatory and fibrous markers (Pref-1) was much higher in CF than in MAT. These observations were fully consistent with those made on CF recovered from five CD patients and compared with subcutaneous and mesenteric fat from the same patients.

CONCLUSIONS

Altogether, this work reports an original experimental mice model of CF. In this model we establish for the first time that CF only occurs in severe colonic inflammation and shows an inflammatory, fibrous but not an adipose pattern.

Divergent Roles for Macrophage C-type Lectin Receptors, Dectin-1 and Mannose Receptors, in the Intestinal Inflammatory Response

Colonic macrophages are considered to be major effectors of inflammatory bowel diseases (IBDs) and the control of gut inflammation through C-type lectin receptors is an emerging concept. We show that during colitis, the loss of dectin-1 on myeloid cells prevents intestinal inflammation, while the lack of mannose receptor (MR) exacerbates it. A marked increase in dectin-1 expression in dextran sulfate sodium (DSS)-exposed MR-deficient mice supports the critical contribution of dectin-1 to colitis outcome. Dectin-1 is crucial for Ly6C^highCCR2^high monocyte population enrichment in the blood and their recruitment to inflamed colon as precursors of inflammatory macrophages. Dectin-1 also promotes inflammasome-dependent interleukin-1β (IL-1β) secretion through leukotriene B4 production. Interestingly, colonic inflammation is associated with a concomitant overexpression of dectin-1/CCL2/LTA4H and downregulation of MR on macrophages from IBD patients. Thus, MR and dectin-1 on macrophages are important mucosal inflammatory regulators that contribute to the intestinal inflammation.

Clinical fate of branch duct and mixed forms of intraductal papillary mucinous neoplasia of the pancreas

AIMS

The aim of the present study was to assess the clinical fate of, and to gain new insights into, branch duct and mixed (predominantly main duct type) forms of intraductal papillary mucinous neoplasia of the pancreas (IPMN).

METHODS

During a 17-year period, 99 successive IPMN patients (52 men, 47 women; mean age, 64 years) were included and divided into two groups for further comparison: one group had branch duct IPMN, whereas the other had mixed IPMN.

RESULTS

Patients from the mixed IPMN group (n = 52) displayed a greater rate of symptoms (83% vs 55%, P = 0.004), pancreatic resection (67% vs 38%, P = 0.007), malignancy (35% vs 13%, P = 0.017) and death (15% vs 4%, P = 0.09) than those from the branch duct IPMN group. A 38-month follow up of non-operated, symptom-free patients confirmed that more than 85% of branch duct IPMN patients were asymptomatic without evidence of malignancy. Borderline lesions and carcinoma are found in up to 50% of symptomatic resected branch duct IPMN cases.

CONCLUSION

Patients with the mixed form of IPMN as well as with symptomatic branch duct IPMN should require pancreatic resection because of symptoms and the risk for malignancy. In silent branch duct IPMN without radiological signs of malignancy, a non-operative watch-and-wait strategy can be discussed.

PIK3CA mutations predict recurrence in localized microsatellite stable colon cancer

PIK3CA, which encodes the p110α catalytic subunit of PI3Kα, is one of the most frequently altered oncogenes in colon cancer (CC), but its prognostic value is still a matter of debate. Few reports have addressed the association between PIK3CA mutations and survival and their results are controversial. In the present study, we aimed to clarify the prognostic impact of PIK3CA mutations in stage I-III CC according to mismatch repair status. Fresh frozen tissue samples from two independent cohorts with a total of 826 patients who underwent curative surgical resection of CC were analyzed for microsatellite instability and screened for activating point mutations in exon 9 and 20 of PIK3CA by direct sequencing. Overall, 693 tumors (84%) exhibited microsatellite stability (MSS) and 113 samples (14%) harbored PIK3CA mutation. In the retrospective training cohort (n = 433), patients with PIK3CA-mutated MSS tumors (n = 47) experienced a significant increased 5-year relapse-free interval compared with PIK3CA wild-type MSS tumors (n = 319) in univariate analysis (94% vs. 68%, Log-rank P = 0. 0003) and in multivariate analysis (HR = 0.12; 95% confidence interval, 0.029-0.48; P = 0.0027). In the prospective validation cohort (n = 393), the favorable prognostic impact of PIK3CA mutations in MSS tumors (n = 327) was confirmed (83% vs. 67%, Log-rank P = 0.04). Our study showed that PIK3CA mutations are associated with a good prognosis in patients with MSS stage I-III CC.

Thrombin modifies growth, proliferation and apoptosis of human colon organoids: a protease-activated receptor 1- and protease-activated receptor 4-dependent mechanism

BACKGROUND AND PURPOSE

Thrombin is massively released upon tissue damage associated with bleeding or chronic inflammation. The effects of this thrombin on tissue regrowth and repair has been scarcely addressed and only in cancer cell lines. Hence, the purpose of the present study was to determine thrombin's pharmacological effects on human intestinal epithelium growth, proliferation and apoptosis, using three-dimensional cultures of human colon organoids.

EXPERIMENTAL APPROACH

Crypts were isolated from human colonic resections and cultured for 6 days, forming human colon organoids. Cultured organoids were exposed to 10 and 50 mU·mL^-1 of thrombin, in the presence or not of protease-activated receptor (PAR) antagonists. Organoid morphology, metabolism, proliferation and apoptosis were followed.

KEY RESULTS

Thrombin favoured organoid maturation leading to a decreased number of immature cystic structures and a concomitant increased number of larger structures releasing cell debris and apoptotic cells. The size of budding structures, metabolic activity and proliferation were significantly reduced in organoid cultures exposed to thrombin, while apoptosis was dramatically increased. Both PAR1 and PAR4 antagonists inhibited apoptosis regardless of thrombin doses. Thrombin-induced inhibition of proliferation and metabolic activity were reversed by PAR4 antagonist for thrombin's lowest dose and by PAR1 antagonist for thrombin's highest dose.

CONCLUSIONS AND IMPLICATIONS

Overall, our data suggest that the presence of thrombin in the vicinity of human colon epithelial cells favours their maturation at the expense of their regenerative capacities. Our data point to thrombin and its two receptors PAR1 and PAR4 as potential molecular targets for epithelial repair therapies.

Malone antegrade colonic irrigation: ileal neoappendicostomy is the preferred procedure in adults

BACKGROUND

Antegrade colonic enema, via a caecal access [Malone antegrade continence enema (MACE)], is proposed to selected patients suffering from incontinence and/or constipation when other therapeutic modalities have failed.

METHODS

We compared complication rates after three MACE techniques: appendicostomy, caecal neoappendicostomy, and ileal neoappendicostomy in 28 adult patients having 31 MACE operations.

RESULTS

Stenoses and leakages occurred more frequently after appendicostomy and caecal flap than after ileal neoappendicostomy. This latter technique appears to reduce morbidity for adult patients.

Simplified identification of Lynch syndrome: a prospective, multicenter study

BACKGROUND

Recommended strategies to screen for Lynch syndrome in colorectal cancer are not applied in daily practice and most of Lynch cases remain undiagnosed.

AIMS

We investigated in routine conditions a strategy that uses simplified clinical criteria plus detection of MisMatch Repair deficiency in tumours to identify Lynch carriers.

METHODS

Colorectal cancer patients that met at least one of three clinical criteria were included: (1) colorectal cancer before 50 years, (2) personal history of colorectal or endometrial cancer, (3) first-degree relative history of colorectal or endometrial cancer. All tumours underwent an MisMatch Repair test combining microsatellite instability analysis and MisMatch Repair immunohistochemistry. Patients with an MisMatch Repair-deficient tumour were offered germline testing.

RESULTS

Of the 307 patients fulfilling the clinical criteria, 46 (15%) had a MisMatch Repair-deficient tumour. Amongst them 27 were identified as Lynch carriers (20 with germline mutation: 12 MLH1, 7 MSH2, 1 MSH6; 7 highly suspected cases despite failure of genetic testing). The simplified clinical criteria selected a population whose MisMatch Repair-deficient status was highly predictive (59%) of Lynch syndrome.

CONCLUSION

This bio-clinical strategy based on simplified clinical criteria combined with an MisMatch Repair test efficiently detected LS cases and is easy to use in clinical practice, outside expert centres.

Gastric bleeding risk following spleen preserving distal pancreatectomy with excision of the splenic vessels: a long-term follow-up

BACKGROUND

Spleen-preserving distal pancreatectomy with resection of the splenic vessels (VR-SPDP) is an effective procedure. However, hemodynamic changes in splenogastric circulation may lead to the development of gastric varices (GV) with a risk of gastrointestinal (GI) bleeding. This retrospective study aimed to assess the long-term postoperative clinical follow-up of patients and review the late postoperative abdominal computed tomography (CT) or endoscopic examination.

METHODS

From 1988 to 2015, 48 consecutive VR-SPDP for benign or low-grade malignant disease were included. Late postoperative follow-up was undertaken with the use of a prospective database and assessment undertaken by CT and/or endoscopy.

RESULTS

The median follow-up was 76 months (range: 12-334 months). Two patients were lost to follow-up. Gastrointestinal hemorrhage occurred in one patient. Endoscopy and abdominal CT showed submucosal GV in five patients. Ten patients had perigastric varices (27%), but none developed clinical complications from their varices. All varices occurred within one year after distal pancreatectomy and remained stable during follow-up.

DISCUSSION

Asymptomatic varices frequently occurred in patients who underwent VR-SPDP, but bleeding risk seemed low. Abdominal CT could identify GV and distinguish submucosal varices with a higher risk of gastric bleeding.

Recurrence risk after Ivor Lewis oesophagectomy for cancer

Objective

The aim of this study was to analyze the profile of tumor recurrence for patients operated on for cancer of oesophagogastric junction or oesophagus by Ivor-Lewis oesophagectomy.

Methods

Patients undergoing potentially curative Ivor-Lewis oesophageal resection between January 1999 to December 2008 at a single center institution were retrospectively analyzed. Their clinical records, details of surgical procedure, postoperative course, pathological findings, recurrence and long term survival were reviewed retrospectively. Univariate and multivariate survival analyses were performed.

Results

One hundred and twenty patients were analyzed. Fifty three patients (44%) presented recurrence during median follow-up of 58 months. Five-year relapse free survival (RFS) rate was 51% (95%CI = [46; 65%]). On multivariate analysis, pT stage > 2 (HR = 2.42, 95%CI = [1.22; 4.79] p = 0.011), positive lymph node status (HR = 3.69; 95% CI = [1.53; 8.96] p = 0.004) and lymph node ratio > 0.2 (HR = 2.57; 95%CI = [1.38; 4.76] p = 0.003) were associated with a poorer RFS and their combination was correlated to relapse risk. Moreover, preoperative tumor stenosis was associated with an increased risk of local recurrence (HR = 3.46; 95% CI = [1.38; 8.70] p = 0.008) whereas poor or undifferentiated tumor was associated with an increased risk of distant recurrence (HR = 3.32; 95% CI = [1.03; 10.04] p = 0.044).

Conclusion

pT stage > 2, positive lymph node status and lymph node ratio > 0.2 are independent prognostic factors of recurrence after Ivor-Lewis surgery for cancer. Their combination is correlated with an increasing risk of recurrence that may argue favorably, in addition with preoperative tumor stenosis assessment, for adjuvant treatment or reinforced follow-up.

Colitis Linked to Endoplasmic Reticulum Stress Induces Trypsin Activity Affecting Epithelial Functions

BACKGROUND AND AIMS

Intestinal epithelial cells [IECs] from inflammatory bowel disease [IBD] patients exhibit an excessive induction of endoplasmic reticulum stress [ER stress] linked to altered intestinal barrier function and inflammation. Colonic tissues and the luminal content of IBD patients are also characterized by increased serine protease activity. The possible link between ER stress and serine protease activity in colitis-associated epithelial dysfunctions is unknown. We aimed to study the association between ER stress and serine protease activity in enterocytes and its impact on intestinal functions.

METHODS

The impact of ER stress induced by Thapsigargin on serine protease secretion was studied using either human intestinal cell lines or organoids. Moreover, treating human intestinal cells with protease-activated receptor antagonists allowed us to investigate ER stress-resulting molecular mechanisms that induce proteolytic activity and alter intestinal epithelial cell biology.

RESULTS

Colonic biopsies from IBD patients exhibited increased epithelial trypsin-like activity associated with elevated ER stress. Induction of ER stress in human intestinal epithelial cells displayed enhanced apical trypsin-like activity. ER stress-induced increased trypsin activity destabilized intestinal barrier function by increasing permeability and by controlling inflammatory mediators such as C-X-C chemokine ligand 8 [CXCL8]. The deleterious impact of ER stress-associated trypsin activity was specifically dependent on the activation of protease-activated receptors 2 and 4.

CONCLUSIONS

Excessive ER stress in IECs caused an increased release of trypsin activity that, in turn, altered intestinal barrier function, promoting the development of inflammatory process.

What is the established contribution of laparoscopy in the treatment of rectal cancer?

The results of laparoscopic treatment of rectal cancer have been evaluated in several randomized trials. Still, the validity of this approach remains controversial because of concerns regarding its oncological safety. In this review, oncological results of laparoscopic rectal resection were similar to those of laparotomy, with no observed survival difference. Conversion from laparoscopy to laparotomy seemed to be associated with worse oncological results and an increased post-operative morbidity including nervous sequelae. Intra-operative blood loss was significantly reduced with the laparoscopic approach, but post-operative morbidity was not different. Post-operative pain and length of hospital stay were decreased by the laparoscopic approach, and short-term quality of life was improved. There was no demonstration of significant reduction in late morbidity such as incisional hernia and bowel adhesions.

Identification of a group with high risk of postoperative complications after deep bowel endometriosis surgery: a retrospective study on 164 patients

PURPOSE

Identify a group with a high risk of postoperative complications after deep bowel endometriosis surgery.

METHODS

We conducted a retrospective study on patients treated from 2012 to 2018 in two departments of gynecological surgery at the Toulouse University Hospital, France. The postoperative complications were evaluated in relation to the surgical management, associated with or without non-digestive surgical procedures, initial disease and patient's characteristics.

RESULTS

164 patients were included. A postoperative complication occurred in 37.8% (n = 62) of the cases and required a secondary surgery in 18.3% (n = 30) of the cases. In the univariate analysis, the risk of postoperative complications increased significantly in the presence of segmental resection, disease progression, and associated urinary tract procedure or vaginal incision. In the multivariate analysis, the risk of overall postoperative complications was associated with the surgical management (p = 0.013 and 0.017) and particularly in the presence of segmental resection [Odds Ratio (OR): 20.87; CI 95% (1.96-221.79)]. The risk of rectovaginal fistula increased in the presence of segmental resection [OR: 22.71; CI 95% (2.74-188.01)] as well as in vaginal incision [OR: 19.67; CI 95% (2.43-159.18); p = 0.005].

CONCLUSION

The risk of overall postoperative complications and rectovaginal fistula in particular increases significantly in the presence of vaginal incision, segmental resection and urinary tract procedures after deep bowel endometriosis surgery.