Preliminary Analysis of Gut Microbiome and Gastrointestinal Symptom Burden in Breast Cancer Patients Receiving Chemotherapy Compared to Healthy Controls

BACKGROUND

Alterations in the naturally occurring bacteria of the gut, known as the gastrointestinal (GI) microbiome, may influence GI symptoms in women with breast cancer.

OBJECTIVE

This work aims to describe GI symptom occurrence, duration, severity, and distress and measures of the GI microbiome among women with breast cancer receiving chemotherapy compared to age- and sex-matched healthy controls.

INTERVENTIONS/METHODS

22 women with breast cancer receiving chemotherapy and 17 healthy control women provided stool specimens and GI symptom data using the modified Memorial Symptom Assessment Scale (MSAS). The fecal microbiome was profiled by metagenomic sequencing of 16S Ribosomal RNA (rRNA). GI microbiome was compared between groups using alpha-diversity (Observed OTU number and Shannon index), beta-diversity (UniFrac distances), and relative abundance of select genera.

RESULTS

GI symptoms with high symptom reports among breast cancer patients included nausea, diarrhea, flatulence, dry mouth, taste change, and poor appetite. Indices of differential abundance (beta diversity) significantly distinguished between breast cancer patients and healthy controls. Unique bacterial features differentiating the 2 groups were Prevotella_9, Akkermansia, Lachnospira, Lachnospiraceae_NK4A136, Lachnoclostridium, and Oscillibacter.

CONCLUSIONS

Gut bacteria are associated with GI inflammation and mucus degradation, suggesting the potential role of the GI microbiome in GI symptom burden. Understanding the influence of GI bacteria on gut health and symptoms will help harness the enormous potential of the GI microbiome as a future diagnostic and therapeutic agent to reduce the symptom burden associated with chemotherapy.

Breast cancer patients from the Midwest region of the United States have reduced levels of short-chain fatty acid-producing gut bacteria

As geographical location can impact the gut microbiome, it is important to study region-specific microbiome signatures of various diseases. Therefore, we profiled the gut microbiome of breast cancer (BC) patients of the Midwestern region of the United States. The bacterial component of the gut microbiome was profiled utilizing 16S ribosomal RNA sequencing. Additionally, a gene pathway analysis was performed to assess the functional capabilities of the bacterial microbiome. Alpha diversity was not significantly different between BC and healthy controls (HC), however beta diversity revealed distinct clustering between the two groups at the species and genera level. Wilcoxon Rank Sum test revealed modulation of several gut bacteria in BC specifically reduced abundance of those linked with beneficial effects such as Faecalibacterium prausnitzii. Machine learning analysis confirmed the significance of several of the modulated bacteria found by the univariate analysis. The functional analysis showed a decreased abundance of SCFA (propionate) production in BC compared to HC. In conclusion, we observed gut dysbiosis in BC with the depletion of SCFA-producing gut bacteria suggesting their role in the pathobiology of breast cancer. Mechanistic understanding of gut bacterial dysbiosis in breast cancer could lead to refined prevention and treatment.

Multiple sclerosis patients have an altered gut mycobiome and increased fungal to bacterial richness

Trillions of microbes such as bacteria, fungi, and viruses exist in the healthy human gut microbiome. Although gut bacterial dysbiosis has been extensively studied in multiple sclerosis (MS), the significance of the fungal microbiome (mycobiome) is an understudied and neglected part of the intestinal microbiome in MS. The aim of this study was to characterize the gut mycobiome of patients with relapsing-remitting multiple sclerosis (RRMS), compare it to healthy controls, and examine its association with changes in the bacterial microbiome. We characterized and compared the mycobiome of 20 RRMS patients and 33 healthy controls (HC) using Internal Transcribed Spacer 2 (ITS2) and compared mycobiome interactions with the bacterial microbiome using 16S rRNA sequencing. Our results demonstrate an altered mycobiome in RRMS patients compared with HC. RRMS patients showed an increased abundance of Basidiomycota and decreased Ascomycota at the phylum level with an increased abundance of Candida and Epicoccum genera along with a decreased abundance of Saccharomyces compared to HC. We also observed an increased ITS2/16S ratio, altered fungal and bacterial associations, and altered fungal functional profiles in MS patients compared to HC. This study demonstrates that RRMS patients had a distinct mycobiome with associated changes in the bacterial microbiome compared to HC. There is an increased fungal to bacterial ratio as well as more diverse fungal-bacterial interactions in RRMS patients compared to HC. Our study is the first step towards future studies in delineating the mechanisms through which the fungal microbiome can influence MS disease.

Abstract PS17-57: Breast cancer patients have reduced levels of short chain fatty acid producing beneficial gut bacteria

The role of the human gut microbiome has been increasingly appreciated in respect to its influence on human health and disease. It has been proposed that dysbiosis in the gut microbiome and subsequent induction of chronic inflammatory state might have an influence on breast cancer development and prognosis. Therefore this study was undertaken to determine the role of gut microbiome in breast cancer. The Breast Molecular Epidemiology Resource (BMER) resources of the Holden Comprehensive Cancer Center (HCCC) were used to recruit 23 women with breast cancer. Fecal samples were used to characterize the gut microbiome of our patient population using 16S rRNA amplification and Illumina sequencing. Reads were then mapped back to amplicon sequence variant using DADA2 pipeline and compared to a cohort of race, age, and gender matched cohort of regional healthy controls. In our preliminary analysis, we observed that breast cancer patients have distinct microbiota compared to age and gender matched healthy controls. We identified depletion of the anti-inflammatory short chain fatty acid producing bacteria specifically Faecalibacterium, Anaerostipes, Parabacteroides and Phascolarctobacterium in feces from BC patients. Additionally, breast cancer cohort showed enrichment of the pro-inflammatory bacteria such as Eubacterium (dolichum), Bifidobacterium, and Blautia. These bacteria have been previously been identified to change with clinical disease stage and/or BMI, as has genus Bifidobacterium (increased in BC cohort). Within BC group, patients with high grade showed lower levels of Eggerthella lenta and Desulfovibrio whereas patients receiving chemotherapy showed depletion of Sulphur reducing Desulfovibrio and methane producing archaea Methanobrevibacter. Further analysis may lead to insights into the interplay between gut microbiome and breast cancer, as well as the feasibility of therapeutic strategies in the form of novel and existing probiotics.

Citation Format: Praveen Vikas, Nicole Cady, Jessica Knobbe, Jemmie Hoang, Meeta Yadav, Melissa Curry, Cathernine Cherwin, Sonia Sugg, Sneha Phadke, Edward Filardo, Ashuthosh Mangalam. Breast cancer patients have reduced levels of short chain fatty acid producing beneficial gut bacteria [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-57.

Bounds on Lorentz Invariance Violation from MAGIC Observation of GRB 190114C

On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording the most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of the speed of light in vacuo for photons as predicted by several quantum gravity models. Based on a set of assumptions on the possible intrinsic spectral and temporal evolution, we obtain competitive lower limits on the quadratic leading order of speed of light modification.

Recent changes in reproductive phenology of a K-selected aquatic insect predator, Belostoma flumineum Say (Heteroptera, Belostomatidae)

The timing of critical events like mating, migration, and development has noticeably and recently shifted in many populations of diverse organisms. Here, we report a change in the breeding phenology of giant waterbugs, Belostoma flumineum Say (Heteroptera, Belostomatidae), in the northeastern United States. Waterbugs collected in 2005 and 2006 exhibited previously typical patterns of mating and reproduction: two annual reproductive peaks in which overwintered adults mated in the spring and young adults from a new generation mated in the fall. In 2012 and 2015, despite similar sampling effort, we detected no fall breeding activity in the study area. Reproductive behaviour under controlled laboratory conditions was also different between the earlier (2005 and 2006) and recent (2012 and 2015) years: waterbugs collected in recent years exhibited significant delays in reproduction (>30 days) under similar photoperiod and thermal conditions. We discuss potential causes of this dramatic change in reproductive behaviour, such as climate change, as well as possible negative impacts of the absence of fall reproduction on populations of B. flumineum in the study region.

Reduction of chronic hepatitis B-related hepatocellular carcinoma with anti-viral therapy, including low risk patients

BACKGROUND

Anti-viral therapy in chronic hepatitis B (CHB) is associated with a reduced risk of hepatocellular carcinoma (HCC) primary described in patients with cirrhosis.

AIM

To examine the effects of treatment on HCC incidence in CHB with and without cirrhosis, after adjustment for background risks.

METHODS

A total of 2255 CHB patients from a US cohort (973 received anti-viral therapy) and 3653 patients from the community-based Taiwanese REVEAL-HBV study, none of whom received treatment. We used Cox proportional hazard models to calculate the risk of developing HCC after adjustment with the previously validated REACH-B risk score.

RESULTS

We found 273 incident cases of HCC. After adjustment, therapy lowered the risk of HCC development in the US treated cohort when compared to the US untreated cohort (HR 0.31; 95% CI: 0.15-0.66; P = 0.002). HCC risk reduction was also confirmed when compared to the REVEAL cohort (HR 0.22; 95% CI: 0.12-0.40; P < 0.001). Each REACH-B point was associated with a 53% increased risk of HCC (HR 1.53; 95% CI 1.46-1.59; P < 0.001). We found a significant statistical reduction in HCC incidence with therapy regardless of gender, age, cirrhosis status, HBeAg serology, alanine aminotransferase level, REACH-B score or treatment medication. Therapy was beneficial to those with mildly- to moderately elevated HBV DNA levels (>2000 IU/mL) and of even greater benefit to those with levels >200 000 IU/mL.

CONCLUSION

After adjustment for background risk, anti-viral therapy was associated with a significant reduction in HCC incidence in both community and real-life clinical cohorts, including in those patients previously thought to be at low risk.

CHOP Contributes to, But Is Not the Only Mediator of, IAPP Induced β-Cell Apoptosis

The islet in type 2 diabetes is characterized by β-cell loss, increased β-cell apoptosis, and islet amyloid derived from islet amyloid polypeptide (IAPP). When protein misfolding protective mechanisms are overcome, human IAPP (h-IAPP) forms membrane permeant toxic oligomers that induce β-cell dysfunction and apoptosis. In humans with type 2 diabetes (T2D) and mice transgenic for h-IAPP, endoplasmic reticulum (ER) stress has been inferred from nuclear translocation of CCAAT/enhancer-binding protein homologous protein (CHOP), an established mediator of ER stress. To establish whether h-IAPP toxicity is mediated by ER stress, we evaluated diabetes onset and β-cell mass in h-IAPP transgenic (h-TG) mice with and without deletion of CHOP in comparison with wild-type controls. Diabetes was delayed in h-TG CHOP(-/-) mice, with relatively preserved β-cell mass and decreased β-cell apoptosis. Deletion of CHOP attenuates dysfunction of the autophagy/lysosomal pathway in β-cells of h-TG mice, uncovering a role for CHOP in mediating h-IAPP-induced dysfunction of autophagy. As deletion of CHOP delayed but did not prevent h-IAPP-induced β-cell loss and diabetes, we examined CHOP-independent stress pathways. JNK, a target of the IRE-1pTRAF2 complex, and the Bcl-2 family proapoptotic mediator BIM, a target of ATF4, were comparably activated by h-IAPP expression in the presence and absence of CHOP. Therefore, although these studies affirm that CHOP is a mediator of h-IAPP-induced ER stress, it is not the only one. Therefore, suppression of CHOP alone is unlikely to be a durable therapeutic strategy to protect against h-IAPP toxicity because multiple stress pathways are activated.

Cushing’s syndrome in a clinic population with diabetes

BACKGROUND

A recent report has suggested that occult Cushing's syndrome (CS) may be present in a significant number of patients with type 2 diabetes mellitus. The aim of this study was to determine whether any patients in our clinic population with diabetes had this condition.

METHODS

One hundred and seventy-one consecutive overweight attendees at the diabetic clinic were enrolled in a study to assess the presence of occult CS. The initial screen was with the 1 mg overnight dexamethasone suppression test and follow-up testing, where indicated was with a 24 h collection for urine-free cortisol.

RESULTS

Thirty-one of 171 patients had a positive result from the overnight dexamethasone suppression test. Follow-up testing with 24 h urine-free cortisol reduced the number of patients with positive results to 3. Two of these were shown to have alcoholic pseudo-CS. The third patient has had several high urine-free cortisol results, in the presence of normal scans of pituitary and adrenals. He has no stigmata of CS and is being observed.

CONCLUSION

Based on the results of our study, there would appear to be little value in screening type 2 diabetics for CS, in the absence of clinical suspicion.

Sex hormone binding globulin stimulates female sexual receptivity

Sex hormone binding globulin (SHBG) is found in the brain and acts directly on plasma membrane-associated receptors in the prostate gland. Infusing SHBG into the medial preoptic area or medial basal hypothalamus of female rats increases their female sexual receptivity. SHBG, SHBG plus estradiol (SHBG-E), and SHBG-E plus oxytocin all significantly increased female sexual receptivity over vehicle or estradiol plus oxytocin infused controls, as measured by lordosis quotients and receptivity scores, at 40, and 90 min after their infusions into the medial preoptic area. When infused into the medial basal hypothalamus, SHBG-E plus oxytocin resulted in significantly increased sexual receptivity 20 and 40 min after infusion when compared to its estradiol plus oxytocin control group. SHBG produced in the brain may be released endogenously to have immediate effects on reproductive physiology and behavior.

Effect of vitamin C on endogenous formation of N-nitrosamines in ureterosigmoidostomy patients

The bacterially catalyzed formation of nitrosamines in the rectosigmoid is a favorite theroy for the increased risk of colon carcinomas following ureterosigmoidostomy. The urine/feces mixtures of 20 ureterosigmoidostomy patients were analyzed for nitrate, nitrite, volatile and nonvolatile nitrosamines prior to, and after, oral administration of vitamin C, a known nitrosation inhibitor. Following a 4-week period of daily ingestion of 2 g vitamin C (1 g in children) there was a slight, but not significant, decrease of volatile and nonvolatile nitrosamines and nitrite, as well as a nonsignificant increase in nitrate in the urine/feces of these patients. No correlation between the vitamin C concentration in serum or urine/feces mixture and the nitrosamine excretion was observed. These results suggest that the administration of vitamin C is not a suitable method for prophylaxis of endogenous nitrosation in ureterosigmoidostomy patients. Clinical and experimental findings implicate that factors other than nitrosamines play an important role in colon carcinogenesis of patients with ureterosigmoidostomies or other forms of urinary diversions using the small or large bowel.

Ureterosigmoidostomy: long-term results, risk of carcinoma and etiological factors for carcinogenesis

We followed postoperatively 75 patients who underwent ureterosigmoidostomy between 1942 and 1987. Of the patients 30 were asked to undergo routine examination, including fiberoptic sigmoidoscopy with biopsy and analysis of a urine-feces slurry for nitrate, nitrite and nitrosamines in comparison to 20 control volunteers. After a mean observation of 14 years 7 months (1 to 46 years) 64.5% of the patients had bilaterally normal kidneys without any previous complications, 77.5% of the renal units being normal. Sigmoidoscopic biopsy revealed 3 carcinomas at the ureterocolonic junction resulting in an 8.5 to 10.5-fold increased risk of colon carcinoma compared to the general population. The excretion of nitrite and N-nitrosamines was increased, and nitrate excretion was decreased compared to healthy control volunteers, suggesting endogenous formation of nitrosamines by bacterially reduced nitrate and endogenous amines. The urological long-term results of ureterosigmoidostomy are similar to those of conduits. However, the increased incidence of colon carcinoma is not yet proved to be higher than in conduits.