Development of a core descriptor set for Crohn's anal fistula

AIM

Crohn's anal fistula (CAF) is a complex condition, with no agreement on which patient characteristics should be routinely reported in studies. The aim of this study was to develop a core descriptor set of key patient characteristics for reporting in all CAF research.

METHOD

Candidate descriptors were generated from published literature and stakeholder suggestions. Colorectal surgeons, gastroenterologists and specialist nurses in inflammatory bowel disease took part in three rounds of an international modified Delphi process using nine-point Likert scales to rank the importance of descriptors. Feedback was provided between rounds to allow refinement of the next ratings. Patterns in descriptor voting were assessed using principal component analysis (PCA). Resulting PCA groups were used to organize items in rounds two and three. Consensus descriptors were submitted to a patient panel for feedback. Items meeting predetermined thresholds were included in the final set and ratified at the consensus meeting.

RESULTS

One hundred and thirty three respondents from 22 countries completed round one, of whom 67.0% completed round three. Ninety seven descriptors were rated across three rounds in 11 PCA-based groups. Forty descriptors were shortlisted. The consensus meeting ratified a core descriptor set of 37 descriptors within six domains: fistula anatomy, current disease activity and phenotype, risk factors, medical interventions for CAF, surgical interventions for CAF, and patient symptoms and impact on quality of life.

CONCLUSION

The core descriptor set proposed for all future CAF research reflects characteristics important to gastroenterologists and surgeons. This might aid transparent reporting in future studies.

Multivisceral resection of locally advanced colorectal cancer in an African referral centre

BACKGROUND

Colorectal cancer (CRC) is common and often presents with advanced disease in Africa. Multivisceral resection (MVR) improves survival in locally advanced (T4b) CRC. The aim was to describe the management and outcomes of patients with clinical T4b CRC without metastatic disease who underwent MVR.

METHODS

A retrospective review of patients with T4 CRC who underwent MVR between January 2008 and December 2013.

RESULTS

Four hundred and ninety-four patients were included. Of the 158 with suspected T4 cancer, 44 had MVR, of which one was excluded due to metastases. The mean age was 64 years. The male to female ratio was 1:1. The most commonly resected extra-colorectal structure was the abdominal wall (21%). The median survival was 68 months (SD 13.9). The 5-year disease free (DFS) and overall survival (OS) were 46% and 55%, respectively. Survival of patients with colon and rectum cancer was similar. Intraoperative tumour spillage, vascular/perineural invasion, and anastomotic leakage were independent predictors of survival.

CONCLUSION

Multivisceral resection of locally advanced (T4b) CRC is feasible in the African context. Complete resection improves survival and should be the goal.

Bilateral versus unilateral botulinum toxin injections for chronic anal fissure: a randomised trial

BACKGROUND

Botulinum toxin injected into the internal anal sphincter is used in the treatment of chronic anal fissure but there is no standardised technique for its administration. This randomised single centre trial compares bilateral (either side of fissure) to unilateral injection.

METHODS

Participants were randomised to receive bilateral (50 + 50 units) or unilateral (100 units) Dysport® injections into the internal anal sphincter in an outpatient setting. Injection-related pain assessed by visual analogue scale was the primary outcome measure. Secondary outcomes were healing rate, fissure pain, incontinence, and global health scores.

RESULTS

Between October 2008 and April 2012, 100 patients with chronic anal fissure were randomised to receive bilateral or unilateral injections. Injection-related pain was comparable in both groups. There was no difference in healing rate. Initially, there was greater improvement in fissure pain in the bilateral group but at 1 year the unilateral group showed greater improvement. Cleveland Clinic Incontinence score was lower in the unilateral group in the early post-treatment period and global health assessment (EuroQol EQ-VAS) was higher in the unilateral group at 1 year.

CONCLUSIONS

Injection-related pain was similar in bilateral and unilateral injection groups. Unilateral injection was as effective as bilateral injections in healing and improving fissure pain without any deterioration in continence.

Abstract PD8-02: Mechanisms of recurrence: Paired analysis of primary and metastatic triple negative breast cancer

Background: Triple negative breast cancer (TNBC) is the most aggressive subtype of invasive breast cancer that lacks ER, PR, and HER2 expression. It is a heterogeneous disease with several molecular subtypes: basal-like1 (BL-1), basal-like 2 (BL-2), mesenchymal (M), and luminal androgen receptor (LAR). Treatment for TNBC is normally limited to chemotherapy, and relapse is common. Here we report molecular alterations associated with TNBC metastasis by analyzing the genomic profiles of paired primary and metastatic TNBCs.

Methods:50 paired TNBCs were identified through an IRB-approved protocol via the City of Hope (COH) Biospecimen Repository. DNA mutation and mRNA expression profiles of 10 paired primary and metastatic TNBCs were analyzed. DNA mutations were identified using exome sequencing by FoundationOne®. Affymetrix Human Genechip 2.0 was used for mRNA expression profiling. Raw data were normalized and processed using Expression Console, and linear regression was performed using Limma to identify the differentially expressed genes between primary and metastatic TNBCs.

Results: DNA mutation profiling showed that multiple mutations occurred within genes covering pathways of PI3K/AKT/mTOR, DNA repair, RAS/MAPK, cell cycle, and growth factor receptor signaling, reconfirming genomic heterogeneity of TNBCs. Gene expression profiles were analyzed for Lehmann's TNBC molecular subtypes (BL-1, BL-2, M, and LAR). Six of ten TNBCs showed phenotype shift between the primary and metastatic TNBCs. Several unique gene expression patterns were identified by comparing the paired TNBCs. CCNE1 and TPX2 were co-overexpressed in metastatic TNBCs compared to paired primaries. This mirrored prior studies in ovarian cancer, where co-overexpression of CCNE1 and TPX2 were found related to clonal resistance against chemotherapy. Splicing factors TRA2B and SRSF7 were also over-expressed in metastatic TNBCs compared with primaries. The analysis studying the association of CCNE1 and TPX2 with overall survival is ongoing using TCGA.

Conclusion: Overall, these results show the comparative changes between primary and relapsed TNBCs and indicate the heterogeneity of molecular mechanisms of recurrence. CNNE1 and TPX2 may represent important genes involved in TNBC metastasis. Further analyses including a total of 50 paired TNBCs are currently underway.

Study Contact: Yuan Yuan MD PhD, City of Hope Comprehensive Cancer Center; Duarte, CA 91030; Email: yuyuan@coh.org

Citation Format: Zhao Z-M, Yost S, Yuan Y-C, Warden C, Chuang J, Yuan Y. Mechanisms of recurrence: Paired analysis of primary and metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD8-02.

Abstract P1-05-26: Genomic analysis of molecular discordance of paired primary and recurrent triple negative breast cancer

Background: Triple negative breast cancer (TNBC) is a heterogeneous disease with several molecular subtypes: basal-like1 (BL1), basal-like 2 (BL-2), mesenchymal(M), mesenchymal-stem-like(MSL), immune-modulatory(IM) and unclassified (UNC) Molecular evolution of TNBC through chemotherapy selection pressure is well recognized but poorly understood. This study was carried out to perform paired genomic analysis of TNBC comparing primary breast cancer with recurrent/refractory disease. Here we report the result of the first10 paired tissue analysis.

Methods: 49 paired specimens were identified through an IRB-approved protocol via COH biorepository search (2002- 2015). miRNA and mRNA profiling of 22 samples were performed. The miRNA libraries were prepared and sequenced on Hiseq2500. Sequences were aligned to hg19 genome and miRNA expression levels were counted by in house built R scripts. Go and pathway annotation was performed using DAVID online tool. Affymetrix human Genechip 2.0st was used for mRNA expression profiling. Raw data were normalized and processed using Expression Console, and linear regression was performed using Limma to identify the differentially expressed genes between primary and recurrent/refractory TNBCs.

Result: Through mRNA profiling, we identified several unique gene expression patterns comparing the paired TNBC. Significant mRNA expression alterations were observed in: cell cycle, DNA repair and adhesion. Using Vanderbilt TNBC sub-classification tool, we have identified “phenotype shift” between primary and recurrent TNBCs. Of the 8 paired specimen analyzed, 3 paired tissue remain in the same subclass (2 in IM, 1 in M). Phenotype shift observed in: 1 from BL1 to BL2, 1 from BL2 to BL1, 1 UNC to IM; 1 MSL to UNC; 1 from M to UNC. 15 up regulated and 13 down regulated miRNAs were identified. Most significantly differentially expressed miRNA (with more than 4 fold expression changes, P-value < 0.001) included: miR-206, miR-203, miR-144, miR-16-2, miR-15b, and miR-20b (un-regulated) and miR-10b, miR-125b and let-7c(down-regulated). These miRNA genes are involved in regulation of hormonal receptor signaling, cell cycle, proliferation and metastases. Statistically significant differentially expressed miRNAs identified from our TNBC patient cohort will be further validated using RT-PCR.

Conclusion: A number of mRNA gene pathways and miRNAs showed differential expression between paired recurrent and primary TNBC tumor specimen. The underlying biology driven the phenotype shift is being studied. Further analysis to include a total of 49 paired TNBCs is currently underway.

Contact information: Yuan Yuan MD PhD, Email: yuyuan@coh.org.

Citation Format: Yuan Y, Li A, Yost S, Yuan Y-C, Chu P, Warden C, Wang J, Liu Z, Liang Y, Goldstein L, Wu X. Genomic analysis of molecular discordance of paired primary and recurrent triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-05-26.

Abstract P6-04-06: Targeting cancer stem cells in triple negative breast cancer by a combination treatment of LBH589 and salinomycin

Background and purpose:

Triple-negative breast cancer (TNBC) is aggressive with poorer prognosis compared to breast cancer that is positive for hormone receptors or HER2. This can be explained further due in part to the existence of breast cancer stem cells (BCSCs). Our lab has found that histone deacetylase (HDAC) inhibitors are effective in the growth suppression of TNBC in vitro and in vivo. To understand the mechanisms involved, we performed RNA-seq analysis for TNBC cells treated with two HDAC inhibitors (LBH589 and Entinostat). Our RNA-seq analysis and studies from other laboratories have found that HDAC inhibitors may modify multiple signaling pathways with undesired effects due to its broad reactivity. To improve the efficacy of HDAC inhibitors in the treatment of TNBCs, we have examined the effects of LBH589 in combination with several drugs. Among them, Salinomycin works effectively with LBH589. It has been used as an antibiotic for farm animals, but has been identified from a screen of a large library of chemicals to target BCSCs (Gupta et al., Cell, 2009). The purpose of this study is to examine the synergistic effect between LBH589 and Salinomycin in the anticipation of their clinical utility and to evaluate a new target therapy to treat TNBC more efficiently and completely.

Material and method:

Two TNBC cell lines (HCC1937, MDA-MB-231) were used as models to examine the combined effects of Salinomycin and LBH589. Cell proliferation studies were performed through 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. To evaluate the effects on BCSC population, mammosphere assay was used for estimating self-renewal capacity and ALDEFLUOR analysis was used for monitoring the distribution of BCSCs in treated samples. For tumor induction experiments, ALDH+ cells were injected into NSG mice. As a therapeutic study, single or combined use of LBH589 (10mg/kg) and Salinomycin (5mg/kg) were peritoneally injected into non-obese diabetic scid gamma (NSG) mice 3 days a week. Tumor volume, body weight and food intake were checked weekly. For mechanistic analysis, qPCR, Western blotting and IHC were performed for gene and protein expression using tumors from mice from different treatments.

Results:

Salinomycin and LBH589 worked synergistically in the suppression of the proliferation of TNBCs (IC50 was 68.8nM and 13.1nM, respectively). Similarly, both drugs inhibited mammosphere formation and ALDH positive population in a synergistic manner. The combination of LBH589 (16nM) with Salinomycin (60nM) reduced 60% of mammosphere formation and 94% of ALDH positive population compared with DMSO treatment. In a mouse model, the combination of LBH589 and Salinomycin had an inhibitory effect on tumor growth compared with the control group and the groups treated with single drug. In all groups, no side effect was seen. The results from mechanistic studies showed that the combination of LBH589 and Salinomycin regulated the Wnt/b-catenin pathway.

Discussion:

We have evidence that the combination of LBH589 and Salinomycin has a synergistic effect on TNBC through Wnt pathway and suggested this combination could potentially be a new therapeutic strategy for exploring targeting therapy in TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-04-06.

Stenting as first-line management for all patients with nonperforating left-sided obstructing colorectal cancer

AIM

Since 2005, we have used self-expanding metal stents (SEMS) as primary treatment for all patients with left-sided obstructing colorectal cancer without evidence of perforation. The purpose of this study was to assess the safety and efficacy of this treatment.

METHOD

This was a prospective study of consecutive patients with left-sided obstructing colorectal cancer without perforation or peritonitis treated between January 2005 and June 2009. SEMS placement was attempted in all cases. Emergency surgery was reserved for patients in whom a stent placement failed. After successful decompression, surgery was offered to patients with potentially curable disease.

RESULTS

Seventy-seven patients were included, with successful SEMS placement in 60/77 (78%) patients, 25 as a bridge to surgery and 35 for palliation. Immediate complications occurred in two (3%) cases. There was no mortality. Of 35 patients in whom SEMS was for palliation, 32 (91%) avoided surgery altogether. A stoma was fashioned in 5 (8.3%) of the 60 patients who were successfully stented, and in 12 (71%) of the 17 patients in whom stenting failed (P = 0.0001).

CONCLUSION

A SEMS-based management protocol for patients with large bowel obstruction due to colorectal cancer is safe and effective.

Genetics of uncoupling proteins in humans

Genetic studies in humans provide a method to test hypotheses about the biological roles of specific genes. So far, ten published papers have chosen to examine the hypothesis that uncoupling protein-2 (UCP2) and/or UCP3 influence energy expenditure and/or body fat accumulation. These genes were chosen because they are candidate energy expenditure genes, based on their homology to UCP1. Studies of UCP2 and UCP3 are intrinsically intertwined because the two genes are separated by only 6000 base pairs on human chromosome 11. Linkage studies in families have suggested that UCP2 and/or UCP3, or a closely linked gene, may influence resting metabolic rate (RMR) Some association studies using a 3' untranslated region insertion/deletion variant of UCP2 have produced statistically positive evidence for association with body mass index (BMI) and RMR. In contrast, association studies of UCP2 using an Ala to Val variant at amino acid 55 have produced negative results. Positive results have also been reported for association of a UCP3 splice variant with respiratory quotient in African Americans. In addition, no studies have reported linkage or association of UCP2 or UCP3 with diabetes. Overall, the results suggest that some variants of UCP2 and UCP3 may be associated with obesity traits in some populations. The UCPs, to date, show positive results in associations with obesity traits but not with diabetes traits. Further work will be needed to settle the role of UCP2 and UCP3 alleles in human body weight regulation.

Obesity and increased contractile activity influence the protein content of UCP2 in human skeletal muscle

The newly discovered uncoupling protein-2 (UCP2) has been proposed to play a critical role in thermoregulatory and substrate oxidation processes. Skeletal muscle mRNA expression and, more recently, the protein content of UCP2 were investigated in humans. These studies have shown that the content of this protein varies quite substantially and that several factors could be responsible for its variation in human skeletal muscle. The aim of this review is to determine whether obesity and low-intensity increased contractile activity contribute to variation in muscle UCP2 content. A recent study from our laboratories revealed that, in obesity, UCP2 content in skeletal muscle is over-expressed by about 1.5-fold compared to lean. Body weight loss in obese subjects did not cause any change in skeletal muscle UCP2 content. On the other hand, when increased muscular contractile activity of knee extensor muscles is induced by several weeks of low-frequency electrical stimulation, UCP2 content increased by about 15%. Obesity and increased contractile activity do not appear sufficient, however, to explain the magnitude of the human skeletal muscle variation in UCP2 content. Since intensive efforts are being devoted to this area of research, it is expected that our understanding of the causes contributing to its variation in humans will soon be substantially improved.

An uncoupling protein 2 gene variant is associated with a raised body mass index but not Type II diabetes

AIMS/HYPOTHESIS

Linkage between markers close to the uncoupling protein 2 and 3 genes (11q13) and resting metabolic rate and a pre-diabetic phenotype have been found. The syntenic region in mouse has been found to be linked to quantitative traits associated with obesity and diabetes. UCP2 and UCP3 could therefore have an important role in body weight regulation and susceptibility to diabetes. We investigated a recently identified variant of the UCP2 gene in exon 8 as a marker for glucose and weight homeostasis.

METHODS

Length variation of the UCP2 exon 8 variant was studied by the polymerase chain reaction and agarose gel electrophoresis. Sequence variants of the UCP3 gene were sought by semi-automated DNA sequencing.

RESULTS

In 453 South Indian subjects, we found an association in women between the UCP2 exon variant and body mass index (p = 0.018). These findings were replicated in a separate group of South Indian subjects (n = 143, p < 0.001) irrespective of sex. Although no association was found between the UCP2 exon 8 variant and overt obesity in British subjects, the UCP2 genotype of obese women (n = 83) correlated with fasting serum leptin concentration (p = 0.006) in the presence of extreme obesity. These observations could not be explained by tight linkage disequilibrium with a coding region variant in the region of the UCP3 gene of biological significance. Lastly, no association was found between UCP2 and Type II (non-insulin-dependent) diabetes using either a family based design (85 families) or case control study (normal glucose tolerance n = 335, impaired glucose tolerance n = 42, Type II diabetes n = 76).

CONCLUSION/INTERPRETATION

We have described a UCP2 gene exon 8 variant that may affect susceptibility to weight gain by influencing regulation of leptin.

BMCP1, a novel mitochondrial carrier with high expression in the central nervous system of humans and rodents, and respiration uncoupling activity in recombinant yeast

We report here the cloning and functional analysis of a novel homologue of the mitochondrial carriers predominantly expressed in the central nervous system and referred to as BMCP1 (brain mitochondrial carrier protein-1). The predicted amino acid sequence of this novel mitochondrial carrier indicates a level of identity of 39, 31, or 30%, toward the mitochondrial oxoglutarate carrier, phosphate carrier, or adenine nucleotide translocator, respectively, and a level of identity of 34, 38, or 39% with the mitochondrial uncoupling proteins UCP1, UCP2, or UCP3, respectively. Northern analysis of mouse, rat, or human tissues demonstrated that mRNA of this novel gene is mainly expressed in brain, although it is 10-30-fold less expressed in other tissues. In situ hybridization analysis of brain showed it is particularly abundant in cortex, hippocampus, thalamus, amygdala, and hypothalamus. Chromosomal mapping indicates that BMCP1 is located on chromosome X of mice and at Xq24 in man. Expression of the protein in yeast strongly impaired growth rate. Analysis of respiration of total recombinant yeast or yeast spheroplasts and in particular of the relationship between respiratory rate and membrane potential of yeast spheroplasts revealed a marked uncoupling activity of respiration, suggesting that although BMCP1 sequence is more distant from the uncoupling proteins (UCPs), this protein could be a fourth member of the UCP family.

Linkage between markers in the vicinity of the uncoupling protein 2 gene and resting metabolic rate in humans

The recent cloning of a gene that codes for a novel uncoupling protein, UCP2, which is expressed in a wide range of adult human tissues, has raised the possibility that it may be involved in regulation of energy balance. To explore this concept we have investigated potential linkage relationships between three microsatellite markers which encompass the UCP2 gene location on 11q13 with resting metabolic rate (RMR), body mass index, percentage body fat (%FAT) and fat mass (FM) in 640 individuals from 155 pedigrees from the Québec Family Study. Using a linkage analysis strategy based on sibling, avuncular, grandparental and cousin pairs, strong evidence of linkage was found between the marker D11S911 (P = 0.000002) and RMR, with more moderate evidence for D11S916 (P = 0.006) and D11S1321 (P = 0.02). Suggestive evidence of linkage was also observed between D11S1321 and %FAT (P = 0.04) and FM (P = 0.02). It is concluded that the three markers encompassing the UCP2 locus and spanning a 5 cM region on 11q13 are linked to resting energy expenditure in adult humans. The evidence is strong enough to warrant a search for DNA sequence variation in the gene itself.

Macrophage lipoprotein receptors

Macrophages possess a number of surface receptors that are capable of mediating the internalization of lipoproteins. The low-density lipoprotein (LDL) receptor of human monocyte macrophages recognizes apolipoprotein B-100 and apolipoprotein E and is rapidly regulated in response to changes in intracellular cholesterol levels. In contrast, in J774 macrophages LDL receptor regulation is defective and LDL can cause massive cholesterol accumulation. The beta migrating very low density lipoprotein (beta-VLDL) receptor is poorly regulated by cellular cholesterol concentrations, readily recognizes apolipoprotein E, poorly recognizes apolipoprotein B-100, and is immunologically related to the LDL receptor. The scavenger receptor (acetyl-LDL receptor) appears to have a molecular weight of 250,000 and is not regulated by cellular cholesterol levels. This receptor recognizes LDL that has been chemically or biologically altered. LDL complexes can also enter macrophages and cause cholesterol accumulation. Examples of such complexes are LDL-dextran sulphate complexes, LDL-proteoglycan aggregates, LDL-mast cell granule complexes, LDL-heparin-fibronectin-denatured collagen complexes, and LDL-antibody complexes. The entry of lipoprotein into macrophages by a pathway that is poorly regulated or is not regulated by cellular cholesterol concentrations appears to be a prerequisite for the formation of arterial foam cells.