Comparison of the composition of bile acids in bile of patients with adenocarcinoma of the pancreas and benign disease

Gut-Liver-Pancreas Axis Crosstalk in Health and Disease: From the Role of Microbial Metabolites to Innovative Microbiota Manipulating Strategies

The functions of the gut are closely related to those of many other organs in the human body. Indeed, the gut microbiota (GM) metabolize several nutrients and compounds that, once released in the bloodstream, can reach distant organs, thus influencing the metabolic and inflammatory tone of the host. The main microbiota-derived metabolites responsible for the modulation of endocrine responses are short-chain fatty acids (SCFAs), bile acids and glucagon-like peptide 1 (GLP-1). These molecules can (i) regulate the pancreatic hormones (insulin and glucagon), (ii) increase glycogen synthesis in the liver, and (iii) boost energy expenditure, especially in skeletal muscles and brown adipose tissue. In other words, they are critical in maintaining glucose and lipid homeostasis. In GM dysbiosis, the imbalance of microbiota-related products can affect the proper endocrine and metabolic functions, including those related to the gut-liver-pancreas axis (GLPA). In addition, the dysbiosis can contribute to the onset of some diseases such as non-alcoholic steatohepatitis (NASH)/non-alcoholic fatty liver disease (NAFLD), hepatocellular carcinoma (HCC), and type 2 diabetes (T2D). In this review, we explored the roles of the gut microbiota-derived metabolites and their involvement in onset and progression of these diseases. In addition, we detailed the main microbiota-modulating strategies that could improve the diseases' development by restoring the healthy balance of the GLPA.

Bile Acids in Pancreatic Carcinogenesis

Pancreatic cancer (PC) is a dangerous digestive tract tumor that is becoming increasingly common and fatal. The most common form of PC is pancreatic ductal adenocarcinoma (PDAC). Bile acids (BAs) are closely linked to the growth and progression of PC. They can change the intestinal flora, increasing intestinal permeability and allowing gut microbes to enter the bloodstream, leading to chronic inflammation. High dietary lipids can increase BA secretion into the duodenum and fecal BA levels. BAs can cause genetic mutations, mitochondrial dysfunction, abnormal activation of intracellular trypsin, cytoskeletal damage, activation of NF-κB, acute pancreatitis, cell injury, and cell necrosis. They can act on different types of pancreatic cells and receptors, altering Ca2+ and iron levels, and related signals. Elevated levels of Ca2+ and iron are associated with cell necrosis and ferroptosis. Bile reflux into the pancreatic ducts can speed up the kinetics of epithelial cells, promoting the development of pancreatic intraductal papillary carcinoma. BAs can cause the enormous secretion of Glucagon-like peptide-1 (GLP-1), leading to the proliferation of pancreatic β-cells. Using Glucagon-like peptide-1 receptor agonist (GLP-1RA) increases the risk of pancreatitis and PC. Therefore, our objective was to explore various studies and thoroughly examine the role of BAs in PC.

The bacterial metabolite, lithocholic acid, has antineoplastic effects in pancreatic adenocarcinoma

Lithocholic acid (LCA) is a secondary bile acid. LCA enters the circulation after bacterial synthesis in the gastrointestinal tract, reaches distantly located cancer cells, and influences their behavior. LCA was considered carcinogenic, but recent studies demonstrated that LCA has antitumor effects. We assessed the possible role of LCA in pancreatic adenocarcinoma. At the serum reference concentration, LCA induced a multi-pronged antineoplastic program in pancreatic adenocarcinoma cells. LCA inhibited cancer cell proliferation and induced mesenchymal-to-epithelial (MET) transition that reduced cell invasion capacity. LCA induced oxidative/nitrosative stress by decreasing the expression of nuclear factor, erythroid 2-like 2 (NRF2) and inducing inducible nitric oxide synthase (iNOS). The oxidative/nitrosative stress increased protein nitration and lipid peroxidation. Suppression of oxidative stress by glutathione (GSH) or pegylated catalase (pegCAT) blunted LCA-induced MET. Antioxidant genes were overexpressed in pancreatic adenocarcinoma and decreased antioxidant levels correlated with better survival of pancreatic adenocarcinoma patients. Furthermore, LCA treatment decreased the proportions of cancer stem cells. Finally, LCA induced total and ATP-linked mitochondrial oxidation and fatty acid oxidation. LCA exerted effects through the farnesoid X receptor (FXR), vitamin D receptor (VDR), and constitutive androstane receptor (CAR). LCA did not interfere with cytostatic agents used in the chemotherapy of pancreatic adenocarcinoma. Taken together, LCA is a non-toxic compound and has antineoplastic effects in pancreatic adenocarcinoma.

Determination of Bile Acids in Canine Biological Samples: Diagnostic Significance

The comprehensive examination of bile acids is of paramount importance across various fields of health sciences, influencing physiology, microbiology, internal medicine, and pharmacology. While enzymatic reaction-based photometric methods remain fundamental for total BA measurements, there is a burgeoning demand for more sophisticated techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) for comprehensive BA profiling. This evolution reflects a need for nuanced diagnostic assessments in clinical practice. In canines, a BA assessment involves considering factors, such as food composition, transit times, and breed-specific variations. Multiple matrices, including blood, feces, urine, liver tissue, and gallbladder bile, offer insights into BA profiles, yet interpretations remain complex, particularly in fecal analysis due to sampling challenges and breed-specific differences. Despite ongoing efforts, a consensus regarding optimal matrices and diagnostic thresholds remains elusive, highlighting the need for further research. Emphasizing the scarcity of systematic animal studies and underscoring the importance of ap-propriate sampling methodologies, our review advocates for targeted investigations into BA alterations in canine pathology, promising insights into pathomechanisms, early disease detection, and therapeutic avenues.

The role of microbial metabolites in endocrine tumorigenesis: From the mechanistic insights to potential therapeutic biomarkers

Microbial metabolites have been indicated to communicate with the host's endocrine system, regulating hormone production, immune-endocrine communications, and interactions along the gut-brain axis, eventually affecting the occurrence of endocrine cancer. Furthermore, microbiota metabolites such as short-chain fatty acids (SCFAs) have been found to affect the tumor microenvironment and boost immunity against tumors. SCFAs, including butyrate and acetate, have been demonstrated to exert anti-proliferative and anti-protective activity on pancreatic cancer cells. The employing of microbial metabolic products in conjunction with radiation and chemotherapy has shown promising outcomes in terms of reducing treatment side effects and boosting effectiveness. Certain metabolites, such as valerate and butyrate, have been made known to improve the efficiency of CAR T-cell treatment, whilst others, such as indole-derived tryptophan metabolites, have been shown to inhibit tumor immunity. This review explores the intricate interplay between microbial metabolites and endocrine tumorigenesis, spanning mechanistic insights to the discovery of potential therapeutic biomarkers.

Microbiomes in pancreatic cancer can be an accomplice or a weapon

Recently, several investigations have linked the microbiome to pancreatic cancer progression. It is critical to reveal the role of different microbiomes in the occurrence, development, and treatment of pancreatic cancer. The current review summarizes the various microbiota types in pancreatic cancer while updating and supplementing the mechanisms of the representative gut, pancreatic, and oral microbiota, and their metabolites during its pathogenesis and therapeutic intervention. Several novel strategies have been introduced based on the tumor-associated microbiome to optimize the early diagnosis and prognosis of pancreatic cancer. The pros and cons involving different microbiomes in treating pancreatic cancer are discussed. The microbiome-related clinical trials for pancreatic cancer theranostics are outlined. This convergence of cutting-edge knowledge will provide feasible ideas for developing innovative therapies against pancreatic cancer.

The Role of Bile Acids in Pancreatic Cancer

Bile acids are well known to promote the digestion and absorption of fat, and at the same time, they play an important role in lipid and glucose metabolism. More studies have found that bile acids such as ursodeoxycholic acid also have anti-inflammatory and immune-regulating effects. Bile acids have been extensively studied in biliary and intestinal tumors but less in pancreatic cancer. Patients with pancreatic cancer, especially pancreatic head cancer, are often accompanied by biliary obstruction and elevated bile acids caused by tumors. Elevated total bile acid levels in pancreatic cancer patients usually have a poor prognosis. There has been controversy over whether elevated bile acids are harmful or beneficial to pancreatic cancer. Still, there is no doubt that bile acids are important for the occurrence and development of pancreatic cancer. This article summarizes the research on bile acid as a biomarker and regulation of the occurrence, development and chemoresistance of pancreatic cancer, hoping to provide some inspiration for future research.

Oral Delivery of Gemcitabine-Loaded Glycocholic Acid-Modified Micelles for Cancer Therapy

The clinical utility of gemcitabine, an antimetabolite antineoplastic agent applied in various chemotherapy treatments, is limited due to the required intravenous injection. Although chemical structure modifications of gemcitabine result in enhanced oral bioavailability, these modifications compromise complex synthetic routes and cause unexpected side effects. In this study, gemcitabine-loaded glycocholic acid-modified micelles (Gem-PPG) were prepared for enhanced oral chemotherapy. The in vitro transport pathway experiments revealed that intact Gem-PPG were transported across the intestinal epithelial monolayer via an apical sodium-dependent bile acid transporter (ASBT)-mediated pathway. In mice, the pharmacokinetic analyses demonstrated that the oral bioavailability of Gem-PPG approached 81%, compared to less than 20% for unmodified micelles. In addition, the antitumor activity of oral Gem-PPG (30 mg/kg, BIW) was superior to that of free drug injection (60 mg/kg, BIW) in the xenograft model. Moreover, the assessments of hematology, blood chemistry, and histology all indicated the hypotoxicity profile of the drug-loaded micelles.

Potential tactics with certain gut microbiota for the treatment of unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) constitutes an extremely malignant form of primary liver cancer. Intricate connections linking to the immune system might be associated with the pathogenesis of HCC. Meanwhile, immunotherapy with immune checkpoint inhibitors has been established to be a favorable therapeutic possibility for advanced HCC. Although curative opportunities for advanced HCC are restricted, the immune checkpoint immunotherapy has developed as the main choice for treating HCC. However, patients with metabolic-associated fatty liver disease (MAFLD)-linked HCC might be less likely to benefit from the immunotherapy alone. The limitation of the effect of the immunotherapy might be owing to the impaired T cell activation in MAFLD patients, which could be well explained by a dysfunctional gut-liver axis. Gut microbiota and their metabolites including several bile acids could contribute to modulating the responses of the immune checkpoint immunotherapy. Roles of gut microbiota in the development of cancers have expected great interest in the latest studies. Here, an interplay between the gut and liver has been presented, which might suggest to affect the efficacy of immune checkpoint immunotherapy against HCC.

Bile Acids and Microbiota Interplay in Pancreatic Cancer

Evidence suggests the involvement of the microbiota, including oral, intra-tumoral and gut, in pancreatic cancer progression and response to therapy. The gut microbiota modulates the bile acid pool and is associated with maintaining host physiology. Studies have shown that the bile acid/gut microbiota axis is dysregulated in pancreatic cancer. Bile acid receptor expression and bile acid levels are dysregulated in pancreatic cancer as well. Studies have also shown that bile acids can cause pancreatic cell injury and facilitate cancer cell proliferation. The microbiota and its metabolites, including bile acids, are also altered in other conditions considered risk factors for pancreatic cancer development and can alter responses to chemotherapeutic treatments, thus affecting patient outcomes. Altogether, these findings suggest that the gut microbial and/or bile acid profiles could also serve as biomarkers for pancreatic cancer detection. This review will discuss the current knowledge on the interaction between gut microbiota interaction and bile acid metabolism in pancreatic cancer.

Impact of gut microbiome in the development and treatment of pancreatic cancer: Newer insights

The gut microbiome plays an important role in the variation of pharmacologic response. This aspect is especially important in the era of precision medicine, where understanding how and to what extent the gut microbiome interacts with drugs and their actions will be key to individualizing therapy. The impact of the composition of the gut microbiome on the efficacy of newer cancer therapies such as immune checkpoint inhibitors and chimeric antigen receptor T-cell treatment has become an active area of research. Pancreatic adenocarcinoma (PAC) has a poor prognosis even in those with potentially resectable disease, and treatment options are very limited. Newer studies have concluded that there is a synergistic effect for immunotherapy in combination with cytotoxic drugs, in the treatment of PAC. A variety of commensal microbiota can affect the efficacy of conventional chemotherapy and immunotherapy by modulating the tumor microenvironment in the treatment of PAC. This review will provide newer insights on the impact that alterations made in the gut microbial system have in the development and treatment of PAC.

Measuring blood cell DNA damage using the PIG-A mutation and CBMN assay in pancreatic cancer patients: a pilot study

Pancreatic cancer still has one of the worst prognoses of all solid malignancies, despite developments in cancer knowledge and care. Research into pancreatic cancer has not fully translated into clinical improvements and as a result, fewer than 1% of patients survive 10 years post-diagnosis. This bleak outlook for patients could be improved by earlier diagnosis. The human erythrocyte phosphatidylinositol glycan class A (PIG-A) assay monitors the mutation status of the X-linked PIG-A gene by measuring glycosyl phosphatidylinositol (GPI)-anchored proteins on the extracellular surface. We have previously identified an elevated PIG-A mutant frequency in oesophageal adenocarcinoma patients and here investigate whether this could be seen in a pancreatic cancer cohort, given the urgent need for novel pancreatic cancer biomarkers. In our pilot study, an elevated PIG-A mutant frequency (5.775 × 10-6 (95% CI 4.777-10) mutants per million) was seen in pancreatic cancer patients (n = 30) when compared to the non-cancer control group (n = 14) who had an erythrocyte mutant frequency of 4.211 × 10-6 (95% CI 1.39-5.16) mutants per million (p = 0.0052). A cut-off value of 4.7 mutants per million provided an AUROC of 0.7595 with a sensitivity of 70% and specificity of 78.57%. A secondary measure of DNA damage in an alternative blood cell population also showed an increase in peripheral lymphocytes using the cytokinesis-block micronucleus assay (p = 0.0164) (AUROC = 0.77, sensitivity = 72.22%, specificity = 72.73%). The micronucleus frequency and PIG-A status show some potential as blood-based biomarkers of pancreatic cancer, but further investigations of these DNA damage tests are required to assess their utility in pancreatic cancer diagnosis.

The pro- and antineoplastic effects of deoxycholic acid in pancreatic adenocarcinoma cell models

BACKGROUND

Commensal bacteria secrete metabolites that reach distant cancer cells through the circulation and influence cancer behavior. Deoxycholic acid (DCA), a hormone-like metabolite, is a secondary bile acid specifically synthesized by intestinal microbes. DCA may have both pro- and antineoplastic effects in cancers.

METHODS AND RESULTS

The pancreatic adenocarcinoma cell lines, Capan-2 and BxPC-3, were treated with 0.7 µM DCA, which corresponds to the reference concentration of DCA in human serum. DCA influenced the expression of epithelial to mesenchymal transition (EMT)-related genes, significantly decreased the expression level of the mesenchymal markers, transcription factor 7- like 2 (TCF7L2), snail family transcriptional repressor 2 (SLUG), CLAUDIN-1, and increased the expression of the epithelial genes, zona occludens 1 (ZO-1) and E-CADHERIN, as shown by real-time PCR and Western blotting. Consequently, DCA reduced the invasion capacity of pancreatic adenocarcinoma cells in Boyden chamber experiments. DCA induced the protein expression of oxidative/nitrosative stress markers. Moreover, DCA reduced aldehyde dehydrogenase 1 (ALDH1) activity in an Aldefluor assay and ALDH1 protein level, suggesting that DCA reduced stemness in pancreatic adenocarcinoma. In Seahorse experiments, DCA induced all fractions of mitochondrial respiration and glycolytic flux. The ratio of mitochondrial oxidation and glycolysis did not change after DCA treatment, suggesting that cells became hypermetabolic.

CONCLUSION

DCA induced antineoplastic effects in pancreatic adenocarcinoma cells by inhibiting EMT, reducing cancer stemness, and inducing oxidative/nitrosative stress and procarcinogenic effects such as hypermetabolic bioenergetics.

What Dietary Patterns and Nutrients are Associated with Pancreatic Cancer? Literature Review

This narrative review summarizes the main findings of observational studies (case-control and cohort) as well as systematic reviews and meta-analyses on the role of nutrients and dietary patterns on pancreatic cancer (PC) risk and elucidates possible mechanisms for the association between nutrients or specific food components and the risk of PC. A literature search of MEDLINE (PubMed), Google Scholar, ScienceDirect, and Scopus was performed. An extensive search of related articles published in the English language from 1985 to 2022 was carried out. Our search included macro- and micronutrient intake as well as dietary patterns associated with PC. In conclusion, the consumption of a diet high in nutrients such as sugar, fats, and red and processed meats can increase the risk of PC. Conversely, a high dietary intake of fresh fruit and vegetables and their associated nutrients like fiber, antioxidants, and polyphenols may prevent PC. Dietary patterns loaded with red and processed meats were also linked to an increased risk of PC, whereas dietary patterns rich in plant-based foods like vegetables, fruits, whole grains, and legumes were associated with a reduced risk of PC. Dietary fiber, fat-soluble vitamins, water-soluble vitamins, and minerals might also play a protective role against PC.

The role of bile acids in carcinogenesis

Bile acids are soluble derivatives of cholesterol produced in the liver that subsequently undergo bacterial transformation yielding a diverse array of metabolites. The bulk of bile acid synthesis takes place in the liver yielding primary bile acids; however, other tissues have also the capacity to generate bile acids (e.g. ovaries). Hepatic bile acids are then transported to bile and are subsequently released into the intestines. In the large intestine, a fraction of primary bile acids is converted to secondary bile acids by gut bacteria. The majority of the intestinal bile acids undergo reuptake and return to the liver. A small fraction of secondary and primary bile acids remains in the circulation and exert receptor-mediated and pure chemical effects (e.g. acidic bile in oesophageal cancer) on cancer cells. In this review, we assess how changes to bile acid biosynthesis, bile acid flux and local bile acid concentration modulate the behavior of different cancers. Here, we present in-depth the involvement of bile acids in oesophageal, gastric, hepatocellular, pancreatic, colorectal, breast, prostate, ovarian cancer. Previous studies often used bile acids in supraphysiological concentration, sometimes in concentrations 1000 times higher than the highest reported tissue or serum concentrations likely eliciting unspecific effects, a practice that we advocate against in this review. Furthermore, we show that, although bile acids were classically considered as pro-carcinogenic agents (e.g. oesophageal cancer), the dogma that switch, as lower concentrations of bile acids that correspond to their serum or tissue reference concentration possess anticancer activity in a subset of cancers. Differences in the response of cancers to bile acids lie in the differential expression of bile acid receptors between cancers (e.g. FXR vs. TGR5). UDCA, a bile acid that is sold as a generic medication against cholestasis or biliary surge, and its conjugates were identified with almost purely anticancer features suggesting a possibility for drug repurposing. Taken together, bile acids were considered as tumor inducers or tumor promoter molecules; nevertheless, in certain cancers, like breast cancer, bile acids in their reference concentrations may act as tumor suppressors suggesting a Janus-faced nature of bile acids in carcinogenesis.

Sequestration of Intestinal Acidic Toxins by Cationic Resin Attenuates Pancreatic Cancer Progression through Promoting Autophagic Flux for YAP Degradation

Simple Summary

Annually, more than 450,000 people are diagnosed with pancreatic cancer worldwide with over 430,000 mortalities. Pancreatic ductal carcinoma (PDAC) accounts for around 80% of pancreatic cancer cases with an extremely high mortality rate. Emerging research has demonstrated that gut dysbiosis is closely associated with pancreatic cancer, while the underlying mechanisms remain elusive. In this study, we found that elevated levels of endotoxin (LPS) and bile acids were associated with malignant progression in Kras-driven pancreatic cancer mice. Importantly, oral administration of cationic resins to sequestrate intestinal endotoxins and bile acids efficiently attenuated tumor progression. Thus, sequestration of intestinal acidic toxins by oral administration of cationic resins may have potential as an intervention strategy for pancreatic malignancy.

Abstract

Pancreatic cancer is driven by risk factors such as diabetes and chronic pancreatic injury, which are further associated with gut dysbiosis. Intestinal toxins such as bile acids and bacterial endotoxin (LPS), in excess and persistence, can provoke chronic inflammation and tumorigenesis. Of interest is that many intestinal toxins are negatively charged acidic components in essence, which prompted us to test whether oral administration of cationic resin can deplete intestinal toxins and ameliorate pancreatic cancer. Here, we found that increased plasma levels of endotoxin and bile acids in Pdx1-Cre: LSL-Kras^G12D/+ mice were associated with the transformation of the pancreatic ductal carcinoma (PDAC) state. Common bile-duct-ligation or LPS injection impeded autolysosomal flux, leading to Yap accumulation and malignant transformation. Conversely, oral administration of cholestyramine to sequestrate intestinal endotoxin and bile acids resumed autolysosomal flux for Yap degradation and attenuated metastatic incidence. Conversely, chloroquine treatment impaired autolysosomal flux and exacerbated malignance, showing jeopardization of p62/ Sqxtm1 turnover, leading to Yap accumulation, which is also consistent with overexpression of cystatin A (CSTA) in situ with pancreatic cancer cells and metastatic tumor. At cellular levels, chenodeoxycholic acid or LPS treatment activated the ligand–receptor-mediated AKT-mTOR pathway, resulting in autophagy-lysosomal stress for YAP accumulation and cellular dissemination. Thus, this work indicates a potential new strategy for intervention of pancreatic metastasis through sequestration of intestinal acidic toxins by oral administration of cationic resins.

A high bile acid environment promotes apoptosis and inhibits migration in pancreatic cancer

Bile acids, the main organic solutes in bile, have been established to play an important role at physiological concentrations in gastrointestinal metabolism. However, under pathological conditions, such as cholestatic disease, cholestasis can damage hepatocytes/biliary epithelial cells leading to apoptosis or necrosis. Clinically, pancreatic head cancer usually presents with obstructive jaundice and increased serum bile acid levels, suggesting that pancreatic cancer is intricately correlated with a high bile acid environment in the human body. An increasing body of evidence suggests that bile acids are toxic to normal human and colon cancer cells. Nonetheless, the effect of bile acids on the occurrence and development of pancreatic cancer remains a matter of debate. In the present study, to explore the direct effects of high serum concentrations of bile acids on pancreatic cancer and the possible related mechanisms, human pancreatic cancer (PANC-1) cells were subject to different concentrations of bile acid mixtures to assess cell viability and the migration and invasion ability. Besides, we found that a high bile acid environment could inhibit the proliferation and migration of pancreatic cancer cells through ROS(Reactive oxygen species) induction and the EMT(epithelial-mesenchymal transition) pathway, thereby promoting the apoptosis of pancreatic cancer cells.Abbreviations BAs: Bile Acids; EMT: epithelial-mesenchymal transition; FBS: fatal bovine serum;CCK-8: Cell-Counting-Kit-8; ROS: reactive oxygen species; CA: cholic acid; CDCA: chenodeoxycholic acid; GCDCA: Glycochenodeoxycholic acid; PVDF: Poly vinylidene fluoride.

Importance of Bile Composition for Diagnosis of Biliary Obstructions

Determination of the cause of a biliary obstruction is often inconclusive from serum analysis alone without further clinical tests. To this end, serum markers as well as the composition of bile of 74 patients with biliary obstructions were determined to improve the diagnoses. The samples were collected from the patients during an endoscopic retrograde cholangiopancreatography (ERCP). The concentration of eight bile salts, specifically sodium cholate, sodium glycocholate, sodium taurocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium glycochenodeoxycholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate as well as bile cholesterol were determined by HPLC-MS. Serum alanine aminotransferase (ALT), aspartate transaminase (AST), and bilirubin were measured before the ERCP. The aim was to determine a diagnostic factor and gain insights into the influence of serum bilirubin as well as bile salts on diseases. Ratios of conjugated/unconjugated, primary/secondary, and taurine/glycine conjugated bile salts were determined to facilitate the comparison to literature data. Receiver operating characteristic (ROC) curves were determined, and the cut-off values were calculated by determining the point closest to (0,1). It was found that serum bilirubin was a good indicator of the type of biliary obstruction; it was able to differentiate between benign obstructions such as choledocholithiasis (at the concentration of >11 µmol/L) and malignant changes such as pancreatic neoplasms or cholangiocarcinoma (at the concentration of >59 µmol/L). In addition, it was shown that conjugated/unconjugated bile salts confirm the presence of an obstruction. With lower levels of conjugated/unconjugated bile salts the possibility for inflammation and, thus, neoplasms increase.

Deoxycholic acid-modified microporous SiO2nanofibers mimicking colorectal microenvironment to optimize radiotherapy-chemotherapy combined therapy

Radiotherapy and chemotherapy remain the main therapeutics for colorectal cancer. However, due to their inevitable side effects on nomal tissues, it is necessary to evaluate the toxicity of radio-/chemotherapy regimens. The newly developedin vitrohigh throughput strategy is promising for these assessments. Nevertheless, the currently monolayer culture condition adopted in the preclinical screening processesin vitrohas been proved not so efficient asin vivosince its poor physiological similarity toin vivomicroenvironment. Herein, we fabricated microporous SiO₂nanofiber mats and further bioactivated with deoxycholic acid (DCA) to mimic the chemical signals in the colorectal cancer microenvironment forin vitroregimen assessment of radiotherapy and chemotherapy. The colorectal cancer cells contacted with the DCA-modified SiO₂nanofiber (SiO₂-DCA NF) mats spatially, and the human intestinal epithelial cell on SiO₂-DCA NF mats exhibited better x-ray and cisplatin tolerance. The distinguishable irradiation and drug tolerance of cells on SiO₂-DCA NF mats indicated that the actual microenvironment of intestine might instruct colorectal cancer differently compared with the common biological experiments. The presented DCA-modified microporous SiO₂nanofibrous mats endowing a better mimicry of colorectal micro-environment, would provide a promising platform forin vitroassessment of radio-/chemotherapy regimens.

Explainable liver tumor delineation in surgical specimens using hyperspectral imaging and deep learning

Surgical removal is the primary treatment for liver cancer, but frequent recurrence caused by residual malignant tissue remains an important challenge, as recurrence leads to high mortality. It is unreliable to distinguish tumors from normal tissues merely under visual inspection. Hyperspectral imaging (HSI) has been proved to be a promising technology for intra-operative use by capturing the spatial and spectral information of tissue in a fast, non-contact and label-free manner. In this work, we investigated the feasibility of HSI for liver tumor delineation on surgical specimens using a multi-task U-Net framework. Measurements are performed on 19 patients and a dataset of 36 specimens was collected with corresponding pathological results serving as the ground truth. The developed framework can achieve an overall sensitivity of 94.48% and a specificity of 87.22%, outperforming the baseline SVM method by a large margin. In particular, we propose to add explanations on the well-trained model from the spatial and spectral dimensions to show the contribution of pixels and spectral channels explicitly. On that basis, a novel saliency-weighted channel selection method is further proposed to select a small subset of 5 spectral channels which provide essentially as much information as using all 224 channels. According to the dominant channels, the absorption difference of hemoglobin and bile content in the normal and malignant tissues seems to be promising markers that could be further exploited.

Cruciferous vegetable consumption and pancreatic cancer: A case-control study

BACKGROUND

Pancreatic cancer is a deadly malignancy with limited screening and few modifiable risk factors. The objective of this study was to investigate the association between a modifiable lifestyle behavior, cruciferous vegetable consumption, and pancreatic cancer, both overall and by subgroups based on non-modifiable, established risk factors.

METHODS

We conducted a hospital-based, case-control study utilizing data from the Patient Epidemiology Data System (1982-1998) at Roswell Park Comprehensive Cancer Center (Buffalo, NY) which included 183 pancreatic cancer patients and 732 cancer-free controls. Data were collected using a self-administered questionnaire including a 52-item food frequency questionnaire and other epidemiologic data. Multivariable logistic regression, adjusted for age, body mass index (BMI), sex, smoking status, total meat, and family history of pancreatic cancer, was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the associations between cruciferous vegetable consumption and pancreatic cancer. Subgroup analyses were conducted by sex, smoking status, and BMI.

RESULTS

We observed inverse associations between cruciferous vegetable intake and pancreatic cancer, with a significant 40% lower odds of pancreatic cancer among subjects consuming >1.5 servings per week (SPW) of raw cruciferous vegetables compared to those consuming less than 0.5 SPW (OR = 0.60, 95% CI: 0.39-0.93). Each additional SPW of total, raw, and cooked cruciferous vegetables was associated with a significant 7-15% lower odds of pancreatic cancer, with the strongest association seen in raw cruciferous vegetables (OR = 0.85, 95% CI: 0.75-0.95). We observed inverse associations between raw cruciferous vegetable intake and pancreatic cancer among people who were overweight, former smokers, and males, ranging from 50% to 59% lower odds.

CONCLUSION

Consuming cruciferous vegetables, especially raw cruciferous vegetables, is a modifiable lifestyle behavior which may be inversely associated with pancreatic cancer, including among subgroups with other non- or not easily modifiable risk factors for this deadly malignancy.

The pathophysiological function of non-gastrointestinal farnesoid X receptor

Farnesoid X receptor (FXR) influences bile acid homeostasis and the progression of various diseases. While the roles of hepatic and intestinal FXR in enterohepatic transport of bile acids and metabolic diseases were reviewed previously, the pathophysiological functions of FXR in non-gastrointestinal cells and tissues have received little attention. Thus, the roles of FXR in the liver, immune system, nervous system, cardiovascular system, kidney, and pancreas beyond the gastrointestinal system are reviewed herein. Gain of FXR function studies in non-gastrointestinal tissues reveal that FXR signaling improves various experimentally-induced metabolic and immune diseases, including non-alcoholic fatty liver disease, type 2 diabetes, primary biliary cholangitis, sepsis, autoimmune diseases, multiple sclerosis, and diabetic nephropathy, while loss of FXR promotes regulatory T cells production, protects the brain against ischemic injury, atherosclerosis, and inhibits pancreatic tumor progression. The downstream pathways regulated by FXR are diverse and tissue/cell-specific, and FXR has both ligand-dependent and ligand-independent activities, all of which may explain why activation and inhibition of FXR signaling could produce paradoxical or even opposite effects in some experimental disease models. FXR signaling is frequently compromised by diseases, especially during the progressive stage, and rescuing FXR expression may provide a promising strategy for boosting the therapeutic effect of FXR agonists. Tissue/cell-specific modulation of non-gastrointestinal FXR could influence the treatment of various diseases. This review provides a guide for drug discovery and clinical use of FXR modulators.

Feasibility of discrimination of gall bladder (GB) stone and GB polyp using voltage-applied SERS measurement of bile juice samples in conjunction with two-trace two-dimensional (2T2D) correlation analysis

Voltage-applied SERS measurement of bile juice in conjunction with two-trace two-dimensional (2T2D) correlation analysis was demonstrated as a potential tool to enhance discrimination of gall bladder (GB) stone and GB polyp. When SERS spectra of the aqueous phases extracted from raw bile juice samples were measured with applying external voltage from -300 to +300 mV (100 mV intervals), subsequent spectral variations of the adsorbed components (bilirubin-containing compounds) on the SERS substrate were minute, and discrimination of the two GB diseases in a principal component score domain was difficult. Therefore, 2T2D correlation analysis, effectively identifying asynchronous (dissimilar) spectral behaviors in the voltage-induced SERS spectra, was used to improve the discrimination. When two spectra of a sample collected with application of +100 and +300 mV were adopted, the features of subsequent 2T2D slice spectra were characteristic, and discrimination of GB stone and GB polyp substantially improved. External voltage application and recognition of the voltage-induced spectral features by 2T2D correlation analysis were key factors for the improvement. Since the demonstrated method relied on only a few SERS-active compounds, infrared (IR) spectroscopy featuring all the present components in the samples was also evaluated for comparison. However, the IR-based discrimination was inferior because the metabolite compositions in the samples between the GB diseases were not noticeably different.

Bile accelerates carcinogenic processes in pancreatic ductal adenocarcinoma cells through the overexpression of MUC4

Pancreatic cancer (PC) is one of the leading causes of mortality rate globally and is usually associated with obstructive jaundice (OJ). Up to date, there is no clear consensus on whether biliary decompression should be performed prior to surgery and how high levels of serum bile affects the outcome of PC. Therefore, our study aims were to characterise the effect of bile acids (BAs) on carcinogenic processes using pancreatic ductal adenocarcinoma (PDAC) cell lines and to investigate the underlying mechanisms. Liquid chromatography-mass spectrometry was used to determine the serum concentrations of BAs. The effects of BAs on tumour progression were investigated using different assays. Mucin expressions were studied in normal and PDAC cell lines and in human samples at gene and protein levels and results were validated with gene silencing. The levels of BAs were significantly higher in the PDAC + OJ group compared to the healthy control. Treating PDAC cells with different BAs or with human serum obtained from PDAC + OJ patients enhanced the rate of proliferation, migration, adhesion, colony forming, and the expression of MUC4. In PDAC + OJ patients, MUC4 expression was higher and the 4-year survival rate was lower compare to PDAC patients. Silencing of MUC4 decreased BAs-induced carcinogenic processes in PDAC cells. Our results show that BAs promote carcinogenic process in PDAC cells, in which the increased expression of MUC4 plays an important role. Based on these results, we assume that in PC patients, where the disease is associated with OJ, the early treatment of biliary obstruction improves life expectancy.

Analysis of bile acids in human biological samples by microcolumn separation techniques: A review

Bile acids are a group of compounds essential for lipid digestion and absorption with a steroid skeleton and a carboxylate side chain usually conjugated to glycine or taurine. Bile acids are regulatory molecules for a number of metabolic processes and can be used as biomarkers of various disorders. Since the middle of the twentieth century, the detection of bile acids has evolved from simple qualitative analysis to accurate quantification in complicated mixtures. Advanced methods are required to characterize and quantify individual bile acids in these mixtures. This article overviews the literature from the last two decades (2000-2020) and focuses on bile acid analysis in various human biological samples. The methods for sample preparation, including the sample treatment of conventional (blood plasma, blood serum, and urine) and unconventional samples (bile, saliva, duodenal/gastric juice, feces, etc.) are shortly discussed. Eventually, the focus is on novel analytical approaches and methods for each particular biological sample, providing an overview of the microcolumn separation techniques, such as high-performance liquid chromatography, gas chromatography, and capillary electrophoresis, used in their analysis. This is followed by a discussion on selected clinical applications.

Quantification of common and planar bile acids in tissues and cultured cells

Bile acids (BAs) have been established as ubiquitous regulatory molecules implicated in a large variety of healthy and pathological processes. However, the scope of BA heterogeneity is often underrepresented in current literature. This is due in part to inadequate detection methods, which fail to distinguish the individual constituents of the BA pool. Thus, the primary aim of this study was to develop a method that would allow the simultaneous analysis of specific C24 BA species, and to apply that method to biological systems of interest. Herein, we describe the generation and validation of an LC-MS/MS assay for quantification of numerous BAs in a variety of cell systems and relevant biofluids and tissue. These studies included the first baseline level assessment for planar BAs, including allocholic acid, in cell lines, biofluids, and tissue in a nonhuman primate (NHP) laboratory animal, Macaca mulatta, in healthy conditions. These results indicate that immortalized cell lines make poor models for the study of BA synthesis and metabolism, whereas human primary hepatocytes represent a promising alternative model system. We also characterized the BA pool of M. mulatta in detail. Our results support the use of NHP models for the study of BA metabolism and pathology in lieu of murine models. Moreover, the method developed here can be applied to the study of common and planar C24 BA species in other systems.

Bile Acids Quantification by Liquid Chromatography-Tandem Mass Spectrometry: Method Validation, Reference Range, and Interference Study

Bile acids (BA) play a pivotal role in cholesterol metabolism. Their blood concentration has also been proposed as new prognostic and diagnostic indicator of hepatobiliary, intestinal, and cardiovascular disease. Liquid chromatography tandem mass spectrometry (LC-MS/MS) currently represents the gold standard for analysis of BA profile in biological samples. We report here development and validation of a LC-MS/MS technique for simultaneously quantifying 15 BA species in serum samples. We also established a reference range for adult healthy subjects (n = 130) and performed a preliminary evaluation of in vitro and in vivo interference. The method displayed good linearity, with high regression coefficients (>0.99) over a range of 5 ng/mL (lower limit of quantification, LLOQ) and 5000 ng/mL for all analytes tested. The accuracies were between 85-115%. Both intra- and inter-assay imprecision was <10%. The recoveries ranged between 92-110%. Each of the tested BA species (assessed on three concentrations) were stable for 15 days at room temperature, 4 °C, and -20 °C. The in vitro study did not reveal any interference from triglycerides, bilirubin, or cell-free hemoglobin. The in vivo interference study showed that pools obtained from hyper-cholesterolemic patients and hyper-bilirubinemic patients due to post-hepatic jaundice for benign cholestasis, cholangiocarcinoma and pancreatic head tumors had clearly distinct patterns of BA concentrations compared with a pool obtained from samples of healthy subjects. In conclusion, this study proposes a new suitable candidate method for identification and quantitation of BA in biological samples and provides new insight into a number of variables that should be taken into account when investigating pathophysiological changes of BA in human diseases.

Feasibility of Voltage-Applied SERS Measurement of Bile Juice as an Effective Analytical Scheme to Enhance Discrimination between Gall Bladder (GB) Polyp and GB Cancer

A unique surface-enhanced Raman scattering (SERS) measurement scheme to discriminate gall bladder (GB) polyp and GB cancer by analysis of bile juice is proposed. Along with the high sensitivity of SERS, external voltage application during SERS measurement was incorporated to improve sample discriminability. For this purpose, Au nanodendrites were constructed on a screen-printed electrode (referred to as AuND@SPE), and Raman spectra of extracted aqueous phases from raw bile juice samples were acquired using the AuND@SPE at voltages from -300 to 300 mV. The sample spectra resembled that of bilirubin, possessing an open chain tetrapyrrole, showing that bilirubin derivatives in bile juice were mainly responsible for the observed peaks. Discrimination of GB polyp and GB cancer using just the normal SERS spectra was not achieved but became apparent when the spectra were acquired at a voltage of -100 mV. When voltage-applied SERS spectra of bilirubin and urobilinogen (one of bilirubin's derivatives) were examined, a sudden intensity elevation occurring at -100 mV was observed for urobilinogen but not bilirubin. Based on examination of corresponding cyclic voltammograms, the potential-driven strong adsorption of urobilinogen (no faradaic charge transfer) on AuND occurring at -100 mV induced a substantial increase in SERS intensity. It was presumed that the content of urobilinogen in the bile juice of a GB cancer patient would be higher than that of a GB polyp patient, and the contained urobilinogen was sensitively highlighted by applying -100 mV during SERS measurement, allowing clear discrimination of GB cancer against GB polyp.

Oncobiosis and Microbial Metabolite Signaling in Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma is one of the most lethal cancers in both men and women, with a median five-year survival of around 5%. Therefore, pancreatic adenocarcinoma represents an unmet medical need. Neoplastic diseases, such as pancreatic adenocarcinoma, often are associated with microbiome dysbiosis, termed oncobiosis. In pancreatic adenocarcinoma, the oral, duodenal, ductal, and fecal microbiome become dysbiotic. Furthermore, the pancreas frequently becomes colonized (by Helicobacter pylori and Malassezia, among others). The oncobiomes from long- and short-term survivors of pancreatic adenocarcinoma are different and transplantation of the microbiome from long-term survivors into animal models of pancreatic adenocarcinoma prolongs survival. The oncobiome in pancreatic adenocarcinoma modulates the inflammatory processes that drive carcinogenesis. In this review, we point out that bacterial metabolites (short chain fatty acids, secondary bile acids, polyamines, indole-derivatives, etc.) also have a role in the microbiome-driven pathogenesis of pancreatic adenocarcinoma. Finally, we show that bacterial metabolism and the bacterial metabolome is largely dysregulated in pancreatic adenocarcinoma. The pathogenic role of additional metabolites and metabolic pathways will be identified in the near future, widening the scope of this therapeutically and diagnostically exploitable pathogenic pathway in pancreatic adenocarcinoma.

Assessing the progression of gastric cancer via profiling of histamine, histidine, and bile acids in gastric juice using LC-MS/MS

Bile acid (BA) imbalance may be directly associated with gastric cancer and indirectly influence stomach carcinogenesis via overexpression of histidine decarboxylase (HDC), which converts histidine (His) into histamine (HIST). Moreover, the progression of gastric cancer, could change the gut microbiome, including bacteria spp. that produce secondary BAs. Gastric juice has various metabolites that could indicate gastric cancer-related stomach conditions. Therefore, profiling of HIST, His, and BAs in gastric juice is crucial for understanding the etiological mechanisms of gastric cancer. We used a profiling method to simultaneously determine targeted metabolites in gastric juice using liquid chromatography-tandem mass spectrometry (LC-MS/MS). We successfully analyzed 70 human gastric juice samples from patients with chronic superficial gastritis (CSG, n = 20), intestinal metaplasia (IM, n = 12), and gastric cancer (n = 38). Furthermore, we investigated the relevance between BA metabolism and gastric cancer. There were statistical differences in the metabolism of cholic acid (CA) into deoxycholic acid (DCA) based on the progression of CSG into IM and gastric cancer. Hence, the progression of gastric cancer might be related to the alterations in gut microbiome composition. We provide insight into the etiological mechanisms of the progression of gastric cancer and biomarkers to diagnose and treat gastric cancer.

Bile acids in glucose metabolism and insulin signalling - mechanisms and research needs

Of all the novel glucoregulatory molecules discovered in the past 20 years, bile acids (BAs) are notable for the fact that they were hiding in plain sight. BAs were well known for their requirement in dietary lipid absorption and biliary cholesterol secretion, due to their micelle-forming properties. However, it was not until 1999 that BAs were discovered to be endogenous ligands for the nuclear receptor FXR. Since that time, BAs have been shown to act through multiple receptors (PXR, VDR, TGR5 and S1PR2), as well as to have receptor-independent mechanisms (membrane dynamics, allosteric modulation of N-acyl phosphatidylethanolamine phospholipase D). We now also have an appreciation of the range of physiological, pathophysiological and therapeutic conditions in which endogenous BAs are altered, raising the possibility that BAs contribute to the effects of these conditions on glycaemia. In this Review, we highlight the mechanisms by which BAs regulate glucose homeostasis and the settings in which endogenous BAs are altered, and provide suggestions for future research.

Long-term oral administration of Exendin-4 to control type 2 diabetes in a rat model

Exendin-4 is a glucagon-like peptide-1 (GLP-1) receptor agonist and potent insulinotropic agent for type 2 diabetes patients; however, its therapeutic utility is limited due to the frequent injections required. Long-acting agonists reduce the number of injections, but they can compromise potency. In this study, chondroitin sulfate-g-glycocholic acid-coated and Exendin-4 (Ex-4)-loaded liposomes (EL-CSG) were prepared for oral administration of Ex-4. The Ex-4 loading efficiency was 77% and the loading content in the nanoparticles was 1 wt-%. In rat models, a single oral dose (200 μg/kg) of EL-CSG showed a relative oral bioavailability of 19.5%, compared with subcutaneous administration (20 μg/kg), and sustained pharmacokinetics for up to 72 h. The overall long-term pharmacodynamic effects, assessed by hemoglobin A1c (HbA1c), body weight, and blood lipid concentrations, of daily oral EL-CSG (300 μg/kg) for four weeks were equivalent to or better than daily subcutaneous injections of free Ex-4 solution (20 μg/kg).