Therapeutic Drug Monitoring in Practice for Inflammatory Bowel Disease.

PURPOSE OF REVIEW: To outline the development, rationale, and practical use of therapeutic drug monitoring in patients with inflammatory bowel disease. RECENT FINDINGS: Therapeutic drug monitoring is traditionally discussed in terms of a proactive or reactive approach. However, these terms are not always consistently defined and can be confusing when translating research to clinical practice. Personalized approaches incorporating clinical context and precision medicine are emerging. Personalized therapeutic drug monitoring combines a structured and proactive strategy for monitoring biologic concentrations as well as identification of antidrug antibody development or subtherapeutic dosing in the setting of loss of response. Optimizing biologic therapy can improve outcomes and avoid loss of response. Why, when, and how we measure drug troughs and anti-drug antibodies is a moving target, though what is known is that the appropriate and evidence-based use of this practice prevents adverse events and improves outcomes in patients with inflammatory bowel disease.

Noninvasive Detection of Colorectal Carcinomas Using Serum Protein Biomarkers.

BACKGROUND: A major roadblock to reducing the mortality of colorectal cancer (CRC) is prompt detection and treatment, and a simple blood test is likely to have higher compliance than all of the current methods. The purpose of this report is to examine the utility of a mass spectrometry-based blood serum protein biomarker test for detection of CRC. MATERIALS AND METHODS: Blood was drawn from individuals (n = 213) before colonoscopy or from patients with nonmetastatic CRC (n = 50) before surgery. Proteins were isolated from the serum of patients using targeted liquid chromatography-tandem mass spectrometry. We designed a machine-learning statistical model to assess these proteins. RESULTS: When considered individually, over 70% of the selected biomarkers showed significance by Mann-Whitney testing for distinguishing cancer-bearing cases from cancer-free cases. Using machine-learning methods, peptides derived from epidermal growth factor receptor and leucine-rich alpha-2-glycoprotein 1 were consistently identified as highly predictive for detecting CRC from cancer-free cases. A five-marker panel consisting of leucine-rich alpha-2-glycoprotein 1, epidermal growth factor receptor, inter-alpha-trypsin inhibitor heavy-chain family member 4, hemopexin, and superoxide dismutase 3 performed the best with 70% specificity at over 89% sensitivity (area under the curve = 0.86) in the validation set. For distinguishing regional from localized cancers, cross-validation within the training set showed that a panel of four proteins consisting of CD44 molecule, GC-vitamin D-binding protein, C-reactive protein, and inter-alpha-trypsin inhibitor heavy-chain family member 3 yielded the highest performance (area under the curve = 0.75). CONCLUSIONS: The minimally invasive blood biomarker panels identified here could serve as screening/detection alternatives for CRC in a human population and potentially useful for staging of existing cancer.

The aryl hydrocarbon receptor as an antitumor target of synthetic curcuminoids in colorectal cancer.

BACKGROUND: Curcumin has proven to be a potent antitumor agent in both preclinical and clinical models of colorectal cancer (CRC). It has also been identified as a ligand of the transcription factor known as the aryl hydrocarbon receptor (AHR). Our laboratory has identified the AHR as a mechanism which contributes to both tumorigenesis in a mouse model of inflammatory CRC as well an apoptotic target in vitro. Curcumin's role as an AHR ligand may modulate its effects to induce colon cancer cell death, and this role may be enhanced via structural modification of the curcumin backbone. We sought to determine if the two piperidone analogs of curcumin, RL66 and RL118, exhibit more robust antitumor actions than their parent compound in the context of colorectal cancer in vitro. Moreover, to ascertain the ability of curcumin, RL66 and RL118 to activate the AHR and evaluate if this activation has any effect on CRC cell death. MATERIALS AND METHODS: DLD1, HCT116, LS513, and RKO colon cell lines were propagated in vitro. Natural curcumin was obtained commercially, whereas RL66 and RL118 were synthesized and characterized de novo. Multiwell fluorescent/luminescent signal detection was used to simultaneously ascertain cell viability, cell cytonecrosis, and relative amounts of apoptotic activity. AHR activity was measured with a dual luciferase reporter gene system. Stable expression of small interfering RNA interference was established in the HCT116 cell lines to create AHR "knock down" cell lines. RESULTS: Both RL66 and RL118 proved to be more potent antitumor agents than their parent compound curcumin in all cell lines tested. The majority of this cell death was due to induction of apoptosis, which occurred earlier and to a greater degree following RL66 and RL118 treatment as opposed to curcumin. Also, RL66 and RL118 were found to be activators of AHR, and a portion of their ability to cause cell death was dependent on this induction. Curcumin was found unable to activate the AHR, and levels of AHR messenger RNA did not change their effects on cell death. CONCLUSIONS: Piperidone analogs of curcumin exhibited enhanced antitumor effects in vitro as opposed to their parent compound. Even more, this enhanced cell death profile may be partially attributed to the ability of these compounds to activate the AHR. Further study of synthetic curcumin analogs as chemopreventives and chemoadjuncts in CRC is warranted. Also, more generally, the AHR may represent a potential putative target for novel anticancer agents for CRC.

The Aryl Hydrocarbon Receptor is a Repressor of Inflammation-associated Colorectal Tumorigenesis in Mouse.

OBJECTIVE: To determine the role of the aryl hydrocarbon receptor (AHR) in colitis-associated colorectal tumorigenesis. BACKGROUND: Colorectal cancer (CRC) is the third most commonly diagnosed cancer in United States. Chronic intestinal inflammation increases the risk for the development of CRC. We investigated the involvement of AHR, a ligand-activated transcriptional regulator, in colitis-associated colorectal tumorigenesis. METHODS: We used a mouse model of colitis-associated colorectal tumorigenesis that employs treatment with azoxymethane and dextran sodium sulfate. We examined the role of AHR using both an Ahr-deletion mouse model (Ahr) and treatment with the AHR pro-agonist indole-3-carbinol (I3C). Incidence, multiplicity, and location of tumors were visually counted. Tumors were defined as neoplasms. Intestinal inflammation was assessed by quantitative PCR for proinflammatory markers and colon length. Data were evaluated and compared using GraphPad Prism software (version 6, La Jolla, CA). RESULTS: Tumor incidence was increased 32% in Ahr null mice and tumor multiplicity was approximately increased 3-fold compared with wild-type mice (2.4 vs 7; P < 0.05). Furthermore, tumor multiplicity was reduced 92% by treatment of I3C in wild-type mice, whereas the suppressor effect of I3C was not observed in Ahr null mice (P < 0.05). CONCLUSIONS: We found that AHR plays a protective role in colitis-associated colorectal tumorigenesis. This conclusion is based on the observations that Ahr null mice showed increased number of colorectal tumors, and mice treated with I3C exhibited fewer tumors. This study supports the use of AHR agonists such as I3C as a chemopreventive therapy for IBD-associated CRC in human patients.

Indole-3-carbinol induces tumor cell death: function follows form.

BACKGROUND: Even with colonoscopy screening and preventive measures becoming more commonplace, colorectal cancer (CRC) remains the third leading cause of oncologic death in the United States as of 2014. Many chemotherapeutics exist for the treatment of colorectal cancer, though they often come with significant side effect profiles or narrow efficacy ranges in terms of patient profile. Dietary phytochemicals such as glucobrassicin and its metabolite indole-3-carbinol (I3C) have been implicated in tumor prevention in many preclinical models across a variety of gastrointestinal tumors and represent an intriguing new class of natural chemotherapeutics for CRC. I3C has been identified as a ligand of the aryl hydrocarbon receptor (AHR), and we aimed to characterize this AHR activation in relation to its cytotoxic properties. METHODS: Human colorectal cancer cell lines DLD1, HCT116, HT-29, LS513, and RKO were treated with indole-3-carbinol or vehicle. Cell viability was assessed via a fluorescent product assay, and apoptotic activity was assessed via a luminescent signal tied to a ratio of caspase-3 and caspase-7 activity. Gene expression of AHR and CYP1A1 messenger ribonucleic acid (mRNA) was measured using quantitative real-time polymerase chain reaction. Small interfering RNA stable expression lines were established on a HCT116 background using a laboratory-developed transfection protocol as published elsewhere. RESULTS: Multiple colorectal cancer cell types express increased CYP1A1 mRNA levels (a specific marker of AHR-driven activity) after treatment with I3C, characterizing I3C treatment as agonistic of this pathway. Also, I3C induced a dose-dependent decrease in cell viability as well as inducing apoptosis. Furthermore, using small interfering RNA interference to knockdown AHR responsiveness generated a significant resistance to the chemotherapeutic actions of indole-3-carbinol regarding both cell viability and apoptotic activity. CONCLUSIONS: Some degree of the cytotoxic and proapoptotic effects of indole-3-carbinol on colon cancer cells is dependent on activation of the aryl hydrocarbon receptor. This represents a novel mechanism for the molecular action of indole-3-carbinol and enhances our understanding of its effects in the context of colorectal cancer. Continued preclinical study of both indole-3-carbinol and the aryl hydrocarbon receptor pathway is warranted, which may one day lead to novel diet-derived colon cancer treatments that enlist the AHR.

Prevalence of cerebrovascular accidents in patients with ulcerative colitis in a single academic health system.

In general, IBD increases arteriovenous thromboembolic events, though the association between UC and cerebrovascular complications remains inconclusive. Some studies suggest young women with UC have an increased risk of cerebrovascular accidents (CVA). The focus of this study was to characterize the rates, anatomic distribution, and risk factors for CVA in patients with UC. We developed a retrospective cohort of patients with UC at a single health care system from June 2010 to June 2015. Neuroimaging was used to document presence, location and type of stroke and traditional risk factors were considered. Prevalence of CVAs in patients with UC was compared to that of the general population of Minnesota (MN) and the United States (U.S.). A total of 2,183 UC patients were identified (1088 females [f-UC], 1095 males [m-UC]). The prevalence of CVA in UC patients (4.7%, 95% CI 3.9-5.6) was higher than in the U.S. (2.5-2.7%, p < 0.0001) and in Minnesota (1.8% CI 1.5-2.2, p < 0.0001) . The prevalence increased in both sexes with a peak prevalence of 24.7% (95% CI 17.1-34.4) in women with UC over the age of 80. Older age, cancer and atrial fibrillation were risk factors for CVA in univariate analysis for both sexes. In multifactorial analysis, both age and atrial fibrillation were risk factors for CVA in the m-UC cohort, but only age was associated with CVA in f-UC. The most common type of CVA was ischemic stroke (77.7%). The most common locations for CVAs in UC patients were frontal and occipital lobes (19% and 18%, respectively). UC patients have an increased risk for CVA, with women over 80 demonstrating the highest risk. Providers should be aware of these risks in making treatment decisions for UC.

Intestinal inflammation and the diet: Is food friend or foe?

Inflammatory bowel disease (IBD) is a chronic intestinal illness of autoimmune origin affecting millions across the globe. The most common subtypes include ulcerative colitis (UC) and Crohn's disease. While many medical treatments for IBD exist, none come without the risk of significant immunosuppression and in general do not have benign side effect profiles. Surgical intervention exists only as radical resection for medically refractory UC. There exists a dire need for novel treatments that target the inherent pathophysiologic disturbances of IBD, rather than global immune suppression. One avenue of investigation that could provide such an agent is the interaction between certain dietary elements and the aryl hydrocarbon receptor (AHR). The AHR is a cytosolic transcription factor with a rich history in environmental toxicant handling, however, recently a role has emerged for the AHR as a modulator of the gastrointestinal immune system. Studies have come to elucidate these effects to include the enhancement of Th cell subset differentiation, interactions between enteric flora and the luminal wall, and modulation of inflammatory interleukin and cytokine signaling. This review highlights advancements in our understanding of AHR activity in the digestive tract and how this stimulation may be wrought by certain dietary "micronutriceuticals", namely indole-3-carbinol (I3C) and its derivatives. Greater clarity surrounding these dynamics could lead to a novel diet-derived agonist of the AHR which is not only non-toxic, but also efficacious in the amelioration of clinical IBD.

Aryl hydrocarbon receptor-dependent apoptotic cell death induced by the flavonoid chrysin in human colorectal cancer cells.

The polyphenolic flavone chrysin has been evaluated as a natural chemopreventive agent due to its anti-cancer effects in a variety of cancer cell lines. However, the mechanism of the chemopreventive effect has been not well established, especially in human colorectal cancer cells. We evaluated the chemopreventive effect of chrysin in three different human colorectal cancer cell lines. We found that chrysin treatment consequently reduced cell viability via induction of apoptosis. We identified that the involvement of up-regulation of pro-apoptotic cytokines tumor necrosis factor (Tnf) α and ß genes and consequent activation of the TNF-mediated transcriptional pathway in chrysin-induced apoptosis. Using our generated AHR siRNA expressing colorectal cancer cells, we demonstrated that the chrysin-induced up-regulation of Tnfα and ß gene expression was dependent on the aryl hydrocarbon receptor (AHR), which is a ligand-receptor for chrysin. Subsequently, we found that the AHR siRNA expressing colorectal cancer cells were resistant to chrysin-induced apoptosis. Therefore, we concluded that AHR is required for the chrysin-induced apoptosis and the up-regulation of Tnfα and ß gene expression in human colorectal cancer cells.