The Possible Preventative Role of Lactate- and Butyrate-Producing Bacteria in Colorectal Carcinogenesis

Background/Aims@#The gut microbiome has emerged as a key player that mechanistically links various risk factors to colorectal cancer (CRC) etiology. However, the role of the gut microbiome in CRC pathogenesis remains unclear. This study aimed to characterize the gut microbiota in healthy controls (HCs) and patients with colorectal adenoma (AD) and CRC in subgroups based on sex and age. @*Methods@#Study participants who visited the hospital for surveillance of CRC or gastrointestinal symptoms were prospectively enrolled, and the gut microbiome was analyzed based on fecal samples. @*Results@#In terms of HC-AD-CRC sequence, commensal bacteria, including lactate-producing (Streptococcus salivarius) and butyrate-producing (Faecalibacterium prausnitzii, Anaerostipes hadrus, and Eubacterium hallii) bacteria, were more abundant in the HC group than in the AD and CRC groups. In the sex comparison, the female HC group had more lactate-producing bacteria (Bifidobacterium adolescentis, Bifidobacterium catenulatum, and Lactobacillus ruminis) than the male HC group. In age comparison, younger subjects had more butyrate-producing bacteria (Agathobaculum butyriciproducens and Blautia faecis) than the older subjects in the HC group.Interestingly, lactate-producing bacteria (B. catenulatum) were more abundant in females than males among younger HC group subjects. However, these sex- and age-dependent differences were not observed in the AD and CRC groups. @*Conclusions@#The gut microbiome, specifically lactate- and butyrate-producing bacteria, which were found to be abundant in the HC group, may play a role in preventing the progression of CRC. In particular, lactate-producing bacteria, which were found to be less abundant in healthy male controls may contribute to the higher incidence of CRC in males.

Anti–PD-L1 Antibody and/or 17β-Estradiol Treatment Induces Changes in the Gut Microbiome in MC38 Colon Tumor Model / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#17β-Estradiol (E2) supplementation suppresses MC38 tumor growth by downregulating the expression of programmed death-ligand 1 (PD-L1). This study aims to figure out the gut microbiota that respond to anti–PD-L1 and/or estrogen treatment in MC38 colon cancer model. @*Materials and Methods@#A syngeneic colon tumor model was developed by injection of MC38 cells into C57BL/6 background male and female mice. Three days before MC38 cells injection, E2 was supplemented to male mice daily for 1 week. Male and female mice with MC38 tumors (50-100 mm3) were injected with anti–PD-L1 antibody. Fresh feces were collected 26 days after injection of MC38 cells and 16S rRNA metagenomics sequencing of DNA extracted from feces was used to assess gut microbial composition. @*Results@#At the taxonomic family level, Muribaculaceae was enriched only in the MC38 male control group. In male mice, linear discriminant analysis effect size analysis at the species level revealed that the four microorganisms were commonly regulated in single and combination treatment with anti–PD-L1 and/or E2; a decrease in PAC001068_g_uc and PAC001070_s (family Muribaculaceae) and increase in PAC001716_s and PAC001785_s (family Ruminococcaceae). Interestingly, in the anti–PD-L1 plus E2 group, a decrease in opportunistic pathogens (Enterobacteriaceae group) and an increase in commensal bacteria (Lactobacillus murinus group and Parabacteroides goldsteinii) were observed. Furthermore, the abundance of Parabacteroides goldsteinii was increased in both males and females in the anti–PD-L1 group. @*Conclusion@#Our results suggest that gut microbial changes induced by the pretreatment of estrogen before anti–PD-L1 might contribute to treatment of MC38 colon cancer.

Supervised Physical Rehabilitation in the Treatment of Patients with Advanced Cancer: a Systematic Review and Meta-analysis

Background@#As the survival rate of cancer patients increases, the clinical importance of rehabilitation provided by healthcare professionals also increases. However, the evidence supporting the relevance of rehabilitation programs is insufficient. This study aimed to review the literature on effectiveness in physical function, quality of life (QOL) or fatigue of supervised physical rehabilitation in patients with advanced cancer. @*Methods@#A systematic review and meta-analysis was conducted following the Cochrane guidelines. We narratively described the results when meta-analysis was not applicable or appropriate. Literature databases including Ovid-MEDLINE, Ovid-EMBASE, and the Cochrane Library, as well as several Korean domestic databases, were searched up to June 2017 for studies that investigated the effectiveness of supervised physical rehabilitation programs on physical function, QOL or fatigue in patients with advanced cancer. The quality of the selected studies was evaluated independently by paired reviewers. @*Results@#Eleven studies with 922 participants were finally selected among 2,459 articles. The meta-analysis revealed that after physical exercise, the physical activity level and strength of patients with advanced cancer increased significantly. The QOL showed a statistically significant improvement after physical rehabilitation according to the European Organization for Research and Treatment of Cancer version C30. Though some of measurements about cardiovascular endurance or strength in several studies were not able to be synthesized, each study reported that they were significantly improved after receiving rehabilitation. @*Conclusion@#Supervised physical rehabilitation for patients with advanced cancer is effective in improving physical activity, strength, and QOL. However, more trials are needed to prove the effectiveness of supervised exercise and to strengthen the evidence.

Walnut phenolic extracts reduce telomere length and telomerase activity in a colon cancer stem cell model

BACKGROUND/OBJECTIVES: Telomeres are located at the chromosomal ends and progressively shortened during each cell cycle. Telomerase, which is regulated by hTERT and c-MYC, maintains telomeric DNA sequences. Especially, telomerase is active in cancer and stem cells to maintain telomere length for replicative immortality. Recently we reported that walnut phenolic extract (WPE) can reduce cell viability in a colon cancer stem cell (CSC) model. We, therefore, investigated the effect of WPE on telomere maintenance in the same model. MATERIALS/METHODS: CD133+CD44+ cells from HCT116, a human colon cancer cell line, were sorted by Fluorescence-activated cell sorting (FACS) and treated with WPE at the concentrations of 0, 10, 20, and 40 µg/mL for 6 days. Telomere lengths were assessed by quantitative real-time PCR (qRT-PCR) using telomere specific primers and DNA extracted from the cells, which was further adjusted with single-copy gene and reference DNA (ddCt ). Telomerase activity was also measured by qRT-PCR after incubating the PCR mixture with cell protein extracts, which was adjusted with reference DNA (dCt ). Transcriptions of hTERT and c-MYC were determined using conventional RT-PCR. RESULTS: Telomere length of WPE-treated cells was significantly decreased in a dose-dependent manner (5.16 ± 0.13 at 0 µg/mL, 4.79 ± 0.12 at 10 µg/mL, 3.24 ± 0.08 at 20 µg/mL and 3.99 ± 0.09 at 40 µg/mL; P = 0.0276). Telomerase activities concurrently decreased with telomere length (1.47 ± 0.04, 1.09 ± 0.01, 0.76 ± 0.08, and 0.88 ± 0.06; P = 0.0067). There was a positive correlation between telomere length and telomerase activity (r = 0.9090; P < 0.0001). Transcriptions of both hTERT and c-MYC were also significantly decreased in the same manner. CONCLUSIONS: In the present cell culture model, WPE reduced telomere maintenance, which may provide a mechanistic link to the effect of walnuts on the viability of colon CSCs.

Comparative Efficacy and Safety of Long-acting Injectable and Oral Second-generation Antipsychotics for the Treatment of Schizophrenia: A Systematic Review and Meta-analysis

We aimed to compare the efficacy and safety of long-acting injectable (LAI) and oral second-generation antipsychotics (SGAs) in treating schizophrenia by performing a systematic review and meta-analysis. MEDLINE, EMBASE, PsycINFO, CINAHL, and the Cochrane Library, as well as five Korean databases, were systemically searched to identify studies published from 2000 to 16 April 2015, which compared the efficacy and safety of LAI and oral SGAs. Using data from randomized controlled trials (RCTs), meta-analyses were conducted. In addition, the GRADE (the Grading of Recommendations, Assessment, Development and Evaluation) approach was applied to explicitly assess the quality of the evidence. A total of 30 studies including 17 RCTs and 13 observational studies were selected. The group treated with LAI SGAs was characterized by significantly lower relapse rates, longer times to relapse and fewer hospital days, but also by a higher occurrence of extrapyramidal syndrome and prolactin-related symptoms than that in the group treated with oral SGAs. Our findings demonstrate that there is moderate to high level of evidence suggesting that in the treatment of schizophrenia, LAI SGAs have higher efficacy and are associated with higher rates of extrapyramidal syndrome and prolactin-related symptoms. Additionally, the use of LAI SGAs should be combined with appropriate measures to reduce dopamine D2 antagonism-related symptoms.